JP7823085B2 - Terminal, wireless communication method and system - Google Patents

Description

The present disclosure relates to a terminal, a wireless communication method and a system in a next-generation mobile communication system.

Long Term Evolution (LTE) was specified for Universal Mobile Telecommunications System (UMTS) networks with the aim of achieving even higher data rates and lower latency (Non-Patent Document 1). Furthermore, LTE-Advanced (3GPP Rel. 10-14) was specified with the aim of achieving even higher capacity and more advanced features than LTE (Third Generation Partnership Project (3GPP) Release (Rel.) 8, 9).

Successor systems to LTE (also known as 5th generation mobile communication system (5G), 5G+ (plus), 6th generation mobile communication system (6G), New Radio (NR), 3GPP Rel. 15 or later, etc.) are also being considered.

3GPP TS 36.300 V8.12.0 “Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (Release 8)”, April 2010

With regard to future wireless communication technologies, the use of artificial intelligence (AI) technologies such as machine learning (ML) for network/device control and management is being considered. For example, the use of AI/ML complementation to reduce reference signal (RS) resources is being considered.

However, the specifics of the RS resource reduction have not yet been fully explored. Unless these are properly defined, highly efficient resource utilization cannot be achieved, and there is a risk that improvements in communication throughput or communication quality may be hindered.

Therefore, one of the objects of the present disclosure is to provide a terminal, a wireless communication method, and a system that can realize suitable use of RS resources.

A terminal according to one aspect of the present disclosure includes a receiving unit that receives at least one of information regarding a time domain resource for a channel state information reference signal, the time domain resource being indicated in a time unit longer than a slot, and information regarding a frequency domain resource for the channel state information reference signal that supports a frequency domain density of at least less than 0.5; and a control unit that measures the channel state information reference signal based on at least one of the information regarding the time domain resource and the information regarding the frequency domain resource, performs machine learning on the measurement results, and performs channel estimation using the machine learning interpolation .

One aspect of the present disclosure enables the use of suitable RS resources.

FIG. 1 is a diagram showing an example of a resource mapping pattern of CSI-RS. FIG. 2 is a diagram illustrating an example of higher layer parameters related to CSI-RS resource mapping information. FIG. 3 is a diagram showing an example of CSI-RS locations within a slot and RB. 4A and 4B are diagrams illustrating an example of CSI-RS resource mapping for a particular CSI-RS location configuration (eg, row). FIG. 5 illustrates another example of CSI-RS resource mapping for a particular CSI-RS location configuration (eg, row). 6A to 6C are diagrams illustrating an example of CSI-RS resource mapping according to aspect 2-1 of the second embodiment. FIG. 7 is a diagram showing an example of a method for indicating the RB position of the CSI-RS resource according to aspect 2-1 of the second embodiment. 8A to 8C are diagrams illustrating an example of CSI-RS resource mapping according to aspect 2-2 of the second embodiment. 9A and 9B are diagrams illustrating another example of CSI-RS resource mapping according to aspect 2-2 of the second embodiment. 10A and 10B are diagrams illustrating another example of CSI-RS resource mapping according to aspect 2-2 of the second embodiment. 11A and 11B are diagrams illustrating another example of CSI-RS resource mapping according to aspect 2-2 of the second embodiment. FIG. 12 is a diagram showing a configuration (for example, row) of a specific CSI-RS position according to aspect 2-2 of the second embodiment. FIG. 13 is a diagram illustrating another example of CSI-RS resource mapping according to aspect 2-2 of the second embodiment. 14A and 14B are diagrams illustrating an example of CSI-RS resource mapping according to a combination of aspect 2-1 and aspect 2-2 of the second embodiment. 15A and 15B are diagrams illustrating another example of CSI-RS resource mapping according to a combination of aspect 2-1 and aspect 2-2 of the second embodiment. 16A and 16B are diagrams illustrating an example of CSI-RS resource mapping according to aspect 2-3 of the second embodiment. FIG. 17 is a diagram illustrating an example of higher layer parameters related to CSI-RS resource mapping information according to aspect 2-3 of the second embodiment. 18A to 18D are diagrams illustrating other examples of CSI-RS resource mapping according to aspect 2-3 of the second embodiment. 19A and 19B are diagrams illustrating another example of CSI-RS resource mapping according to aspect 2-3 of the second embodiment. 20A and 20B are diagrams illustrating an example of CSI-RS resource mapping according to a combination of aspect 2-2 and aspect 2-3 of the second embodiment. 21A and 21B are diagrams illustrating an example of CSI-RS resource mapping according to a combination of aspect 2-1, aspect 2-2, and aspect 2-3 of the second embodiment. FIG. 22 is a diagram illustrating an example of a schematic configuration of a wireless communication system according to an embodiment. FIG. 23 is a diagram illustrating an example of the configuration of a base station according to an embodiment. FIG. 24 is a diagram illustrating an example of the configuration of a user terminal according to an embodiment. FIG. 25 is a diagram illustrating an example of the hardware configuration of a base station and a user terminal according to an embodiment. FIG. 26 is a diagram illustrating an example of a vehicle according to an embodiment.

(CSI-RS)
In Rel. 15/16 NR, for example, a CSI-RS is used as a DL RS for at least one of channel state information (CSI) acquisition, beam management (BM), beam failure recovery (BFR), and fine tracking of time and frequency.

In Rel. 15/16 NR, multiple CSI-RS ports are multiplexed using at least one of frequency division multiplexing (FDM), time division multiplexing (TDM), and code division multiplexing (CDM (frequency domain OCC, time domain OCC)). CSI-RS supports up to 32 ports.

Multiple-port CSI-RS are used, for example, to orthogonalize multi-input multi-output (MIMO) layers. For example, for single-user MIMO, a different DMRS port is configured for each layer. For multi-user MIMO, a different DMRS port is configured for each layer within one UE and for each UE.

In Rel. 15/16 NR, CSI-RS supports up to 32 ports using at least one of time-domain OCC and frequency-domain OCC (up to 4 in the time direction and up to 2 in the frequency direction), FDM, and TDM. CSI-RS supports periodic, semi-persistent, and aperiodic transmission. The frequency density of CSI-RS is configurable to adjust overhead and CSI estimation accuracy.

<CSI-RS time domain>
A predetermined periodicity (e.g., periodicity) is set for the periodic/semi-persistent CSI-RS. In Rel. 16 NR and earlier, the predetermined periodicity is set in slot units, specifically, any of 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 160, 320, and 640 slots. In the case of aperiodic CSI-RS, all aperiodic CSI-RS resources in the same resource set are transmitted in the same slot.

<CSI-RS resource mapping pattern>
In Rel. 15/16 NR, the CSI-RS supports 1, 2, 4, 8, 12, 16, 24, and 32 ports (antenna ports, CSI-RS ports), and supports frequency domain densities (e.g., frequency domain densities) of 3, 1, and 0.5.

The CDM types supported for CSI-RS are non-CDM (e.g., no CDM) and CDM. Supported CDM types include fd-CDM2, cdm4-FD2-TD2, and cdm8-FD2-TD4 (see Figure 1). fd-CDM2 multiplexes two CSI-RSs at the same time and frequency by multiplying a frequency domain (FD)-orthogonal cover code (OCC) of length 2 on an RE-by-RE basis (FD2). cdm4 multiplexes four CSI-RSs at the same time and frequency by multiplying a length-2 FD-OCC by a length-2 time domain (TD)-OCC on an RE-by-symbol basis (cdm4-FD2-TD2). Cdm8 multiplexes 8-port CSI-RS at the same time and frequency by multiplying a length 2 FD-OCC by a length 4 TD-OCC on an RE-by-symbol basis (cdm8-FD2-TD4).

CSI-RS supports OFDM symbol allocation (e.g., OFDM symbol allocation) of 1 or 2 starting symbols in a slot, and supports allocation of 1/2/4 adjacent symbols from each starting symbol.

The frequency domain allocation of the CSI-RS may be indicated by a bitmap (e.g., bitmap indication). For example, the frequency-domain location of the CSI-RS may be determined based on a bitmap provided by a higher layer parameter related to CSI-RS resources (e.g., frequencyDomainAllocation) and a predetermined value (e.g., ki). The frequencyDomainAllocation may be included in a higher layer parameter related to CSI-RS resource mapping (e.g., CSI-RS-ResourceMapping IE (see Figure 2) or CSI-RS-ResourceConfigMobility IE).

The predetermined value (e.g., ki) for the frequency position of the CSI-RS (e.g., CDM group) within a slot may be a value defined in a table for CSI-RS positions (see Figure 3).

Figure 3 shows an example of the location of CSI-RS within a slot. Each row in the table indicates the row number, the number of ports, the frequency domain density, the CDM type, the time and frequency (time/frequency) location (the location of the component resource (CDM group) (k bar, l bar)), the CDM group index, and the location of each resource within the component resource ((RE, symbol), (k', l')). Here, the time/frequency location is the location of the time and frequency resource (component resource) of the CSI-RS corresponding to one port. The k bar is represented by an overlined "k." The k bar indicates the starting resource element (RE) index of the component resource, and the l bar indicates the starting symbol (OFDM symbol) index of the component resource.

In each row of the table relating to CSI-RS positions shown in FIG. 3, the following relationships may be defined:
Row 1 (row#1): [b3...b0],k _i-1 =f(i)
Row 2 (row#2): [b11...b0],k _i-1 =f(i)
Row 4 (row#4): [b2...b0],k _i-1 =4f(i)
Other rows (cases other than row #1/#2/#4): [b5……b0], k _i-1 =2f(i)
f(i) denotes the number of the i-th bit of a bitmap (e.g., frequencyDomainAllocation) that is set to 1, and is repeated every 1/ρ ceiling function (e.g., ceil(1/ρ)) among the resource blocks configured for CSI-RS reception by the UE.

For example, Figure 4A shows an example of CSI-RS positions corresponding to row #1, where the number of ports is 1, the density is 3, and there is no CDM.

Figure 4B shows an example of CSI-RS positions corresponding to row 4 (row #4). This example shows the case where the number of ports is 4, the density is 1, and fd-CDM2 is used. In the frequency domain and time domain of 1 PRB x 1 slot, two component resources of 2 subcarriers x 1 symbol are multiplexed (FDM) in the frequency domain and one in the time domain, thereby mapping 2 x 1 component resources. Furthermore, the CSI-RS in each component resource is multiplied by an FD-OCC with a length of 2 subcarriers, thereby multiplexing (CDM) two CSI-RS. The CSI-RS includes two CDM groups. For example, the first CDM group (CDM group #0) includes two ports (e.g., port 3000, port 3001), and the second CDM group (CDM group #1) includes two ports (e.g., port 3002, port 3003).

Figure 5 shows an example of the CSI-RS position corresponding to row #17. This example shows the case where the number of ports is 32, the density is 1 (or 0.5), and cdm4-FD2-TD2. In the frequency domain and time domain of 1 PRB x 1 slot, 4 component resources of 2 subcarriers x 2 symbols are multiplexed (FDM) in the frequency domain and 2 component resources are multiplexed (TDM) in the time domain, thereby mapping 4 x 2 component resources. Furthermore, the CSI-RS in each component resource is multiplied by a 2-subcarrier FD-OCC and a 2-symbol TD-OCC, thereby multiplexing (CDM) 4 CSI-RS. The CSI-RS includes 8 CDM groups, each of which includes 4 ports.

(Application of Artificial Intelligence (AI) technology to wireless communications)
Regarding future wireless communication technologies, the use of AI technology for network/device control and management is being considered.

For example, in future wireless communication technologies, particularly in communications using beams, there is a demand for high accuracy in channel estimation (also called channel measurement) for beam management, decoding of received signals, etc.

Channel estimation may be performed using at least one of, for example, a channel state information reference signal (CSI-RS), a synchronization signal (SS), a synchronization signal/physical broadcast channel (SS/PBCH) block, a demodulation reference signal (DMRS), or a sounding reference signal (SRS).

Regarding future wireless communication technologies, it is being considered to utilize artificial intelligence (AI) technologies such as machine learning (ML) for network/device control and management.

For example, it is being considered to use AI/ML complementation to reduce reference signal (RS) resources while maintaining channel estimation accuracy.

For example, if learning using AI/ML has not been performed (completed) in a terminal (user terminal, also referred to as User Equipment (UE))/base station, the following requirements may be necessary to achieve RS reception measurements that enable high channel estimation accuracy or accurate RS reception measurements used for learning:
- Transmitting and receiving RS in a wide band (contributing to improved reception quality);
Repeatedly transmitting RS to combine received channels/signals (combined reception) on the receiving side (contributing to improved reception quality);
High time/frequency density of RS resources (helps to obtain good time/frequency correlation).

Taking these factors into consideration, it is believed that the appropriate allocation of RSs will differ depending on whether AI/ML has been sufficiently trained or not. Therefore, it is desirable to introduce a method and framework for dynamically allocating appropriate RS resources.

However, the specific content of this framework has yet to be fully explored. Unless these are properly defined, highly efficient resource utilization cannot be achieved, and there is a risk that improvements in communication throughput or communication quality may be hindered.

In addition, existing specifications (prior to Rel. 16) stipulate that the mapping settings for reference signals (e.g., CSI-RS) are controlled based on a predetermined periodicity and a predetermined resource mapping.

In order to achieve highly efficient resource utilization as described above, it is desirable to reduce the overhead of reference signals (e.g., CSI-RS/CSI-RS resources) by configuring more flexible and dynamic reference signal mapping.

The inventors therefore considered suitable methods for allocating/utilizing RS resources and came up with the present embodiment.

Note that each embodiment of the present disclosure may be applied when AI/ML/prediction is not used. In this case, it is possible to change RS settings with reduced delay/overhead without RRC reconfiguration.

In one embodiment of the present disclosure, a UE/BS trains an ML model in a training mode and executes the ML model in a test mode (also referred to as a test mode, etc.). In the test mode, the accuracy of the trained ML model may be validated.

In the present disclosure, the UE/BS may input channel state information, reference signal measurements, etc. into the ML model and output highly accurate channel state information/measurements/beam selection/position, future channel state information/radio link quality, etc.

In the present disclosure, AI may be interpreted as an object (also referred to as a subject, object, data, function, program, etc.) having (implementing) at least one of the following characteristics:
- Estimation based on observed or collected information;
- selections based on observed or collected information;
- Predictions based on observed or collected information.

In the present disclosure, the object may be, for example, an apparatus or device such as a terminal or base station. The object may also correspond to a program included in the apparatus.

In addition, in the present disclosure, an ML model may be interpreted as an object having (implementing) at least one of the following characteristics:
- Producing estimates by feeding information,
- Predicting estimates by providing information
- Discover features by providing information,
-Select an action by providing information.

In the present disclosure, the term "ML model" may be interpreted as at least one of an AI model, predictive analytics, a predictive analysis model, etc. The ML model may also be derived using at least one of regression analysis (e.g., linear regression analysis, multiple regression analysis, logistic regression analysis), a support vector machine, a random forest, a neural network, deep learning, etc. In the present disclosure, the term "model" may be interpreted as at least one of an encoder, a decoder, a tool, etc.

Based on the input information, the ML model outputs at least one piece of information, such as an estimate, a prediction, a selected action, or a classification.

Embodiments of the present disclosure will be described in detail below with reference to the drawings. The wireless communication methods according to the embodiments may be applied independently or in combination.

In the following embodiments, to explain the ML model for communication between a UE and a BS, the relevant entities are a UE and a BS, but the application of each embodiment of the present disclosure is not limited to this. For example, for communication between other entities (e.g., communication between UEs), the UE and BS in the following embodiments may be replaced with a first UE and a second UE. In other words, the UE, BS, etc. in the present disclosure may all be replaced with any UE/BS.

In this disclosure, "A/B" and "at least one of A and B" may be read interchangeably, and "A/B/C" and "at least one of A, B, and C" may be read interchangeably.

In this disclosure, terms such as activate, deactivate, indicate, select, configure, update, and determine may be read interchangeably. In this disclosure, terms such as support, control, controllable, operate, and operable may be read interchangeably.

In the present disclosure, the terms Radio Resource Control (RRC), RRC parameters, RRC messages, higher layer parameters, information elements (IEs), and configurations may be interchangeable. In the present disclosure, the terms Medium Access Control (MAC) Control Element (CE), update commands, and activation/deactivation commands may be interchangeable.

In the present disclosure, the terms panel, UE panel, panel group, beam, beam group, precoder, uplink (UL) transmitting entity, TRP, spatial relationship information (SRI), spatial relationship, SRS resource indicator (SRI), SRS resource, control resource set (CONTROLLER RESOLUTION SET (CORESET)), Physical Downlink Shared Channel (PDSCH), codeword, base station, reference signal, predetermined antenna port (e.g., demodulation reference signal (DMRS) port), predetermined antenna port group (e.g., DMRS port group), predetermined group (e.g., code division multiplexing (CDM) group, predetermined reference signal group, CORESET group), predetermined resource (e.g., predetermined reference signal resource), predetermined resource set (e.g., predetermined reference signal resource set), CORESET pool, PUCCH group (PUCCH resource group), spatial relationship group, downlink Transmission Configuration Indication The terms "TCI state" (DL TCI state), uplink TCI state (UL TCI state), unified TCI state, common TCI state, quasi-co-location (QCL), QCL assumption, etc. may be read as interchangeable terms.

In this disclosure, the terms index, ID, indicator, and resource ID may be interchangeable. In this disclosure, the terms sequence, list, set, group, cluster, subset, etc. may be interchangeable.

In the present disclosure, beam report may be interchangeably referred to as beam measurement report, CSI report, CSI measurement report, predicted beam report, predicted CSI report, etc.

In the present disclosure, CSI-RS may be interchangeably read as at least one of non-zero power (NZP) CSI-RS, zero power (ZP) CSI-RS, and CSI interference measurement (CSI-IM).

In this disclosure, the measured/reported RS may refer to the RS measured/reported for beam reporting.

In this disclosure, timing, time, duration, slot, subslot, symbol, subframe, etc. may be interpreted interchangeably.

In this disclosure, terms such as direction, axis, dimension, polarization, and polarization component may be interchangeable.

In this disclosure, estimation, prediction, and inference may be interpreted interchangeably. In this disclosure, estimate, predict, and infer may be interpreted interchangeably.

In the present disclosure, the RS may be, for example, a CSI-RS, an SS/PBCH block (SS block (SSB)), etc. Furthermore, the RS index may be a CSI-RS resource indicator (CSI-RS Resource Indicator (CRI)), an SS/PBCH block resource indicator (SS/PBCH Block Indicator (SSBRI)), etc.

In the present disclosure, CSI feedback, CSI feedback information, CSI report, CSI report, CSI transmission, CSI information, CSI, etc. may be read interchangeably.

In addition, in the present disclosure, subbands may be interchangeably referred to as physical resource blocks (PRBs), subcarriers, arbitrary frequency resource units, etc.

(Wireless communication method)
As an example of a (specific) reference signal described in each embodiment of the present disclosure, a channel state information reference signal (CSI-RS) is used, but this is not limited to this and may be applied to any reference signal.

In the present disclosure, the terms "assigning," "mapping," "transmitting," and "receiving" a reference signal may be interpreted interchangeably.

First Embodiment
In the first embodiment, the time domain configuration of CSI-RS resources is described.

It may be possible to support the setting/application of a value greater than the maximum periodicity in existing systems (e.g., Rel. 16 and earlier) as the periodicity of CSI-RS resources. For example, it may be possible to support the setting/application of a predetermined periodicity value greater than 640 slots as the periodicity of CSI-RS resources. The predetermined periodicity value may be, for example, 1280 slots, 2560 slots, etc.

In this way, by supporting the setting/application of a larger value for the periodicity of CSI-RS resources than in existing systems, it is possible to reduce the overhead of CSI-RS resources.

In addition, a new offset value (e.g., a time offset value) of the CSI-RS resource may be set for a given periodicity value. For example, a setting of 0 to (X-1) slots may be supported as an offset corresponding to a periodicity of X slots.

The predetermined periodicity value may be set at a granularity/unit other than a slot. For example, configuration of the periodicity of CSI-RS resources (e.g., a predetermined periodicity value) may be supported using units with a granularity greater than a slot (e.g., subframes/frames/ms/s/minis/hours). In this case, the periodicity offset value may be set at the granularity of a slot, or may be set at a new granularity (e.g., a unit with a granularity greater than a slot).

For example, the offset corresponding to the subframe/frame/ms/s/min/hours of periodicity X may be set to 0 to (X-1) slots. Alternatively, the offset corresponding to the subframe/frame/ms/s/min/hours of periodicity X may be set to 0 to (X-1) subframe/frame/ms/s/min/hours. The granularity/unit of the periodicity and the granularity/unit of the offset may be set/applied in common.

By supporting a granularity greater than the slot for the CSI-RS periodicity value/offset value, it is possible to suppress the increase in overhead of higher layer signaling even when the periodicity value/offset value becomes large.

Second Embodiment
In the second embodiment, the frequency domain setting of the CSI-RS resource will be described. Note that the configuration shown in the second embodiment may be applied in appropriate combination with the content shown in the first embodiment.

<<Aspect 2-1>>
The frequency domain density (e.g., frequency domain density) value of the CSI-RS resource may be set/applied to a value different from the values (e.g., 3, 1, 0.5) of the existing system. The newly set/applied frequency domain density value may be applied to each row of the CSI-RS resource positions shown in FIG. 3, or may be selectively applied to some rows.

Alternatively, the newly set/applied frequency domain density value may be applied to a new row different from the rows (e.g., row #1 to row #18) indicating the CSI-RS resource positions shown in FIG. 3. Note that in the present disclosure, row may be interpreted as a configuration of CSI-RS positions (e.g., CSI-RS locations within a slot) or a CSI-RS position candidate.

At least one of the following options 2-1-1 to 2-1-2 may be applied as a new frequency domain density (e.g., ρ_new) different from the frequency domain densities of the existing system (e.g., 3, 1, 0.5).

[Option 2-1-1]
The new frequency-domain density (e.g., ρ_new) may be defined as 1/N, where N may be a predetermined integer value. Alternatively, N may be a multiple of 2, 4, 8, 12, etc. For example, the new frequency-domain density value 1/N may be a value less than 0.5.

If the new frequency domain density (e.g., ρ_new) is 1/N, this may mean that the CSI-RS resource mapping pattern (e.g., row) is repeated only once every N (=1/ρ_new) resource blocks (e.g., RBs).

Figure 6A shows an example of a CSI-RS resource mapping pattern (or parameters) corresponding to row #2, and Figure 6B shows an example of a CSI-RS position corresponding to row #2. Here, the number of ports is 1, the density is 1/4 (N = 4, ρ_new = 1/4), and CDM is not used. In other words, the CSI-RS resource mapping pattern (here, row #2) is repeated once every four resource blocks (e.g., RBs).

N in terms of frequency domain density may be signaled to the UE via higher layer signaling.

[Option 2-1-2]
The new frequency domain density (e.g., ρ_new) may be defined as M/N, where M is a predetermined integer value, and N may be a predetermined integer value or a multiple of 2, 4, 8, 12, etc. M and N may be set separately or may be defined as M<N (or M>N). For example, the new frequency domain density value M/N may be a value smaller than 0.5 or a value larger than 0.5. Furthermore, 1/ρ may be an integer value or may not be an integer value.

The M/N ratio related to frequency domain density may be notified to the UE by higher layer signaling. The values of M and N may also be notified to the UE separately. In this case, controlling the values of M and N allows for flexible setting of frequency domain density.

If the new frequency-domain density value (e.g., ρ_new) is M/N, this may mean that the CSI-RS resource mapping pattern is repeated for M resource blocks (e.g., RBs) every N (= 1/ρ_new) resource blocks (e.g., RBs). The M RBs may be consecutive or non-consecutive RBs.

Figure 6C shows an example of a CSI-RS position corresponding to row #2. Here, the number of ports is 1, the density is 2/5 (M = 2, N = 5, ρ_new = 2/5), and CDM is not used. In other words, the CSI-RS resource mapping pattern is repeated for every 5 resource blocks (e.g., RBs) by 2 RBs. Here, the case where the 2 RBs repeated every 5 RBs are non-contiguous is shown, but this is not limited to this.

If the new frequency domain density shown in Option 2-1-1/Option 2-1-2 is supported, the RB positions occupied by CSI-RS (e.g., occupied RB position(s)) may be defined in the specifications or may be instructed to the UE by the network. The RB positions occupied by CSI-RS may also be interpreted as the RB positions where CSI-RS is placed/mapped/assigned.

《Alt2-1-1》
A starting RB position within the N RBs may be defined/indicated, for example, an offset of the starting RB position relative to the lowest (or highest) RB index among the N RBs may be defined/indicated.

In option 2-1-1, the indicated starting RB position may refer to the RB position occupied by CSI-RS.

In option 2-1-2, the M RBs occupied by the CSI-RS may be frequency-allocated with a fixed offset (e.g., Y RB offset) between the RBs occupied by the CSI-RS. In this case, Y may be set by higher layer signaling or may be defined in the specifications. Y defined in the specifications (e.g., Y = 0) may mean that consecutive RBs among the N RBs are allocated to the CSI-RS.

If the starting RB position is not indicated/set, a default starting position may be applied. The default starting position may be, for example, the lowest (or highest) RB index among the N RBs.

The starting RB position among the N RBs may be included in a table used for CSI-RS resource mapping positions or in higher layer parameters for CSI-RS resource mapping.

《Alt2-1-2》
To indicate the RBs occupied by CSI-RS for every N RBs, a bitmap indicating the RB position (e.g., RB position) for the new frequency domain density value may be set (see Figure 7).

For example, in option 2-1-1, only one of the multiple bits indicating the RBs occupied by CSI-RS may be set to 1. In option 2-1-2, the total number of bits set to 1 may be set to be equal to M.

For example, "0001" may mean that the CSI-RS pattern is mapped to the first (or last) RB of every four RBs. "00010101" may mean that the CSI-RS pattern is mapped to the {i, i+2, i+4}th RB or the {i+3, i+5, i+7}th RB of every eight RBs.

If the starting RB position is not specified/configured, a default starting position may be applied. The default starting position may be, for example, a configuration in which the M consecutive RBs with the lowest (or highest) RB index among the N RBs are occupied by the CSI-RS.

The bitmap may be included in a table used for CSI-RS resource mapping locations, or may be included in higher layer parameters for CSI-RS resource mapping.

<<Aspect 2-2>>
If the frequency domain density of the CSI-RS resources (e.g., frequency domain density) is less than 1, mapping/allocation of CSI-RS resources (e.g., different ports/CDM groups) to multiple RBs (or different RBs) may be supported.

For example, when the frequency domain density is less than 1, the configuration of CSI-RS positions within a slot (e.g., CSI-RS locations within a slot) may be applied across multiple RBs (or different RBs). The configuration of CSI-RS positions within a slot may be, for example, at least one of row #1 to row #18 (or a newly defined/configured row) included in the table shown in FIG. 3.

Figure 8A shows an example of a CSI-RS resource mapping pattern (or parameters) corresponding to row #14, and Figure 8B shows an example of a CSI-RS position in an existing system corresponding to row #14. Here, the case is shown where the number of ports is 24, the density is 0.5, and cdm4-FD2-TD2. In other words, the CSI-RS resource mapping pattern (or row 14) is repeated once every two RBs. Also, Figure 8B shows a case where CSI-RS is mapped to one of the two RBs and not mapped to the other.

In Figure 8B, in the frequency domain and time domain of 1 PRB x 1 slot, component resources of 2 subcarriers x 2 symbols are multiplexed three times (FDM) in the frequency domain and two times (TDM) in the time domain to map 3 x 2 component resources. Furthermore, the CSI-RS in each component resource is multiplied by an FD-OCC of length 2 subcarriers and a TD-OCC of length 2 symbols, thereby multiplexing (CDM) four CSI-RS. The CSI-RS includes six CDM groups, each of which includes four ports.

Figure 8C shows an example of the CSI-RS position corresponding to row #14 when the second aspect is applied. Here, the case is shown where the number of ports is 24, the density is 0.5, and cdm4-FD2-TD2. In other words, the CSI-RS resource mapping pattern is repeated once every two resource blocks (e.g., RBs). Also, here, the CSI-RS is mapped to both two RBs (or across two RBs). For example, different ports/CDM groups are mapped to each of the two RBs.

In Figure 8C, in the frequency domain and time domain of 2 PRBs x 1 slot, 3 component resources of 2 subcarriers x 2 symbols are multiplexed (FDM) in the frequency domain and 2 component resources are multiplexed (TDM) in the time domain to map 3 x 2 component resources. Furthermore, the CSI-RS in each component resource is multiplied by a FD-OCC of length 2 subcarriers and a TD-OCC of length 2 symbols, thereby multiplexing (CDM) 4 CSI-RS. The CSI-RS includes 6 CDM groups, each of which includes 4 ports. This example shows the case where CDM groups 0, 1, 3, and 4 are mapped to the first RB, and CDM groups 2 and 5 are mapped to the second RB.

In this way, by mapping different ports/different CDM groups corresponding to CSI-RS (e.g., CSI-RS positions corresponding to a specific row) to multiple RBs, it is possible to achieve flexibility in CSI-RS mapping and obtain frequency domain diversity. It is also possible to reduce the frequency domain density in one slot. Furthermore, by applying this in combination with aspect 2-1, it is possible to effectively reduce the frequency domain density.

When the frequency domain density is less than 1, in cases where different ports/different CDM groups are mapped to multiple RBs, the range of values for kbar/ki in the CSI-RS location configuration (e.g., CSI-RS resource mapping table) may be extended/changed. In this case, the bitmap length (or size) set/signaled by higher layer parameters related to frequency domain allocation (e.g., FrequencyDomainAllocation) may be extended. The higher layer parameters (e.g., frequencyDomainAllocation) may indicate frequency domain resource occupation (e.g., frequency domain resource occupation) in multiple RBs.

The bitmap length set/signaled by higher layer parameters may be changeable (or variable) based on predetermined conditions (e.g., the frequency domain density of the CSI-RS). For example, if the frequency domain density is 0.5, the bitmap length (or size) may be doubled. In addition, the value range of kbar/ki may be expanded (e.g., [0, 22] (for FD2), [0, 23] (for fd-CDM2)).

Furthermore, bitmap length extension may be supported only for a specific CSI-RS position configuration (e.g., a specific row), only for all rows, or for a new row. A specific row may be, for example, a row other than row #1, row #2, and row #4. A new row may be a row introduced for the purpose of mapping different CDM groups/ports to different RBs.

If the bitmap lengths of rows other than row #1, row #2, and row #4 are extended, the following relationship may be defined for each row of the table relating to the CSI-RS position.
Row 1 (row#1): [b3...b0],k _i-1 =f(i)
Row 2 (row#2): [b11...b0],k _i-1 =f(i)
Row 4 (row#4): [b2...b0],k _i-1 =4f(i)
Other rows (cases other than row #1/#2/#4): [b11……b0], k _i-1 =2f(i)
f(i) denotes the number of the i-th bit in the bitmap that is set to 1 and is repeated every two consecutive RBs (for example, when the frequency domain density is 0.5).

Also, higher layer parameters for RBs indicated for frequency domain density 0.5 (e.g., {evenPRBs,oddPRBs}) may indicate the RBs to which a particular CDM group (e.g., CDM group 0) is mapped.

Figure 9A shows an example of a CSI-RS resource mapping pattern corresponding to row #14. The network (e.g., a base station) may indicate to the UE a bitmap with an expanded size as an upper layer parameter (e.g., frequencyDomainAllocation) related to the frequency domain allocation of CSI-RS. Here, the case where "100000001010" is indicated as the bitmap corresponding to row #14 is shown.

The UE selects a row (here, row #14) corresponding to the CSI-RS based on higher layer parameters including a bitmap notified by the base station, and then determines the frequency domain location of the CSI-RS. The UE may determine the row based on the port/density/CDM type notified by the higher layer parameters, or information specifying the row may be notified to the UE by the higher layer parameters.

When the frequency domain density for row #14 is 0.5, the UE determines that the frequency domain location of the CSI-RS (each component resource) is k0=2, k1=6, k2=22 based on [b11...b0], _{k i-1} =2f(i) and the bitmap (100000001010) (see Figure 9B).

Figure 9B shows a case where CSI-RS (different CDM groups/ports) corresponding to row #14 are mapped in two RBs. The frequency domain positions of CSI-RS corresponding to CDM groups 0 and 3 are determined based on k0 (= 2), the frequency domain positions of CSI-RS corresponding to CDM groups 1 and 4 are determined based on k1 (= 6), and the frequency domain positions of CSI-RS corresponding to CDM groups 2 and 5 are determined based on k2 (= 22). Note that the reference point for ki in the frequency direction may be one of multiple (here, two) RBs (e.g., subcarrier 0 of the RB with the smaller index).

Figure 9A illustrates the use of rows included in a table related to CSI-RS locations in an existing system, but this is not limited to this. When mapping different CDM groups/ports to different RBs, new CSI-RS location configurations (e.g., new rows) may be supported (see Figure 10A).

Figure 10A shows an example of a CSI-RS resource mapping pattern corresponding to a new row #x. Here, the number of ports is 48, the density is 0.5, and the frequency domain is cdm4-FD2-TD2. The frequency domain is represented by k0, k1, k2, k3, k4, and k5.

The network (e.g., a base station) may indicate to the UE the expanded-size bitmap as a higher layer parameter (e.g., frequencyDomainAllocation) related to the frequency domain allocation of CSI-RS. Here, we show the case where "101010101010" is indicated as the bitmap corresponding to row #x.

The UE selects a row (here, row #x) corresponding to the CSI-RS based on higher layer parameters including a bitmap notified by the base station, and then determines the frequency domain location of the CSI-RS. The UE may determine the row based on the port/density/CDM type notified by the higher layer parameters, or information specifying the row may be notified to the UE by the higher layer parameters.

For row #x, the UE determines that the frequency domain positions of the CSI-RS (each component resource) are k0=2, _k1 =6, k2=10, k3=14, k4=18, k5=22 based on [b11...b0],k i-1 =2f(i) and the bitmap (101010101010) (see Figure 10B).

Figure 10B shows an example of CSI-RS locations corresponding to row #x. CSI-RS resources are mapped to both of the two RBs (or across the two RBs). For example, different ports/CDM groups are mapped to each of the two RBs. Here, CDM groups 0, 1, 2, 6, 7, and 8 are mapped to the first RB, and CDM groups 3, 4, 5, 9, 10, and 11 are mapped to the second RB.

The frequency domain position of the CSI-RS corresponding to CDM groups 0 and 6 is determined based on k0 (= 2). Similarly, the frequency domain position of the CSI-RS corresponding to CDM groups 1 and 7 is determined based on k1 (= 6), the frequency domain position of the CSI-RS corresponding to CDM groups 2 and 8 is determined based on k2 (= 10), the frequency domain position of the CSI-RS corresponding to CDM groups 3 and 9 is determined based on k3 (= 14), the frequency domain position of the CSI-RS corresponding to CDM groups 4 and 10 is determined based on k4 (= 18), and the frequency domain position of the CSI-RS corresponding to CDM groups 5 and 11 is determined based on k5 (= 22). Note that the reference point for ki in the frequency direction may be one of multiple (here, two) RBs (e.g., subcarrier 0 of the RB with the smaller index).

Figures 9A and 10A show cases where the bitmap length is extended, but it is also possible to have a configuration where the bitmap length is not extended and an offset is added to the k bar (e.g., ki) defined/set in the CSI-RS position configuration (e.g., row) (or the range of the k bar is extended).

In this case, a new row may be introduced in the table related to CSI-RS locations, and the range of kbar/ki in the new row may be defined differently from that of the existing row. For example, 0≦kbar≦12/ρ-1, 0≦ki≦11 may be used. The indicated resource mapping allocation (kbar, lbar) may be repeated in 1/ρ RBs. Higher layer parameters related to frequency domain allocation (e.g., frequencyDomainAllocation) may indicate the location of frequency domain resource allocation in one RB.

Figure 11A shows an example of a CSI-RS resource mapping pattern corresponding to a new row #x. Here, the number of ports is 24, the density is 0.5, and cdm4-FD2-TD2 is shown. It also shows a case where the frequency domain is represented by k0, k1+12, and k2. In other words, an offset (here, +12) is added in the frequency direction to the CDM group corresponding to k1 (here, CDM groups 1 and 4).

The network (e.g., a base station) may indicate to the UE a bitmap whose size is not expanded as a higher layer parameter (e.g., frequencyDomainAllocation) related to the frequency domain allocation of CSI-RS. Here, the case where "101010" is indicated as the bitmap corresponding to row #x is shown.

The UE selects a row (here, row #x) corresponding to the CSI-RS based on higher layer parameters including a bitmap notified by the base station, and then determines the frequency domain location of the CSI-RS. The UE may determine the row based on the port/density/CDM type notified by the higher layer parameters, or information specifying the row may be notified to the UE by the higher layer parameters.

For row #x, the UE determines k0=2, k1=6, k2=10 based on [b5...b0], k _i-1 =2f(i) and the bitmap (101010), and determines the frequency domain location of the CSI-RS (each component resource) (see Figure 11B).

Figure 11B shows an example of CSI-RS locations corresponding to row #x. CSI-RS resources are mapped to both of the two RBs (or across the two RBs). For example, different ports/CDM groups are mapped to each of the two RBs. Here, CDM groups 0, 2, 3, and 5 are mapped to the first RB, and CDM groups 1 and 4 are mapped to the second RB.

The frequency domain location of the CSI-RS corresponding to CDM groups 0 and 3 is determined based on k0 (= 2). The frequency domain location of the CSI-RS corresponding to CDM groups 1 and 4 is determined based on k1 (= 6) + 12. The frequency domain location of the CSI-RS corresponding to CDM groups 2 and 5 is determined based on k2 (= 10).

The reference point of ki in the frequency direction may be one of multiple (here, two) RBs (e.g., subcarrier 0 of the RB with the smaller index). Alternatively, the reference point of ki with a predetermined offset (here, 12) added may be the other RB (e.g., subcarrier 0 of the RB with the larger index).

Figures 12 and 13 show other examples of mapping different CDM groups to different RBs by extending kbar (or adding an offset to ki).

Figure 12 shows an example of a CSI-RS resource mapping pattern (or parameters) corresponding to row #x and row #y, respectively. Here, the number of ports is 48, the density is 0.5, and cdm4-FD2-TD2 is shown. Also, the frequency domain is shown as k0, k1, k2, k0+12, k1+12, k2+12. Here, the values of (k bar, l bar) corresponding to each CDM group are defined differently (or in reverse order) in row #x and row #y.

The network (e.g., a base station) may indicate to the UE a bitmap whose size is not expanded as a higher layer parameter (e.g., frequencyDomainAllocation) related to the frequency domain allocation of CSI-RS. Here, the case where "101010" is indicated as the bitmap corresponding to row #x/row #y is shown.

The UE selects a row (here, row #x or row #y) corresponding to the CSI-RS based on higher layer parameters including a bitmap notified by the base station, and then determines the frequency domain location of the CSI-RS. The UE may determine the row based on the port/density/CDM type notified by the higher layer parameters, or information specifying the row may be notified to the UE by the higher layer parameters.

For row #x/row #y, the UE determines k0=2, k1=6, k2=10 based on [b5...b0], k _i-1 =2f(i) and the bitmap (101010), and determines the frequency domain position of the CSI-RS (each component resource) (see Figure 13).

Figure 13 shows an example of CSI-RS locations corresponding to row #x and row #y, respectively. CSI-RS resources are mapped to both of the two RBs (or across the two RBs). For example, different ports/CDM groups are mapped to the two RBs.

Here, for row #x, CDM groups 0, 1, 2, 6, 7, and 8 are mapped to the first RB, and CDM groups 3, 4, 5, 9, 10, and 11 are mapped to the second RB. The frequency domain locations of the CSI-RS corresponding to CDM groups 0 and 6 are determined based on k0 (= 2), the frequency domain locations of the CSI-RS corresponding to CDM groups 1 and 7 are determined based on k1 (= 6), and the frequency domain locations of the CSI-RS corresponding to CDM groups 2 and 8 are determined based on k2 (= 10). The frequency domain locations of the CSI-RS corresponding to CDM groups 3 and 9 are determined based on k0 (= 2) + 12, the frequency domain locations of the CSI-RS corresponding to CDM groups 4 and 10 are determined based on k1 (= 6) + 12, and the frequency domain locations of the CSI-RS corresponding to CDM groups 5 and 11 are determined based on k2 (= 10) + 12.

On the other hand, for row #y, CDM groups 0, 1, 2, 3, 4, and 5 are mapped to the first RB, and CDM groups 6, 7, 8, 9, 10, and 11 are mapped to the second RB. The frequency domain locations of the CSI-RS corresponding to CDM groups 0 and 3 are determined based on k0 (= 2), the frequency domain locations of the CSI-RS corresponding to CDM groups 1 and 4 are determined based on k1 (= 6), and the frequency domain locations of the CSI-RS corresponding to CDM groups 2 and 5 are determined based on k2 (= 10). The frequency domain locations of the CSI-RS corresponding to CDM groups 6 and 9 are determined based on k0 (= 2) + 12, the frequency domain locations of the CSI-RS corresponding to CDM groups 7 and 10 are determined based on k1 (= 6) + 12, and the frequency domain locations of the CSI-RS corresponding to CDM groups 8 and 11 are determined based on k2 (= 10) + 12.

In this way, by adding an offset to ki corresponding to each CDM group, it becomes possible to flexibly control the RB to which the CDM group is mapped when the frequency domain density of the CSI-RS is less than 1.

In the above explanation, a case where the frequency domain density is 0.5 is shown as a case where the frequency domain density is smaller than 1, but the applicable frequency domain density is not limited to 0.5. Aspect 2-2 may be applied to frequency domain densities other than 0.5 (for example, Aspect 2-1 and Aspect 2-2 may be applied in combination).

Figure 14A shows an example of a CSI-RS resource mapping pattern corresponding to row #14. Here, a frequency domain density of 1/4 (N=4) is supported.

The network (e.g., a base station) may indicate to the UE the expanded size bitmap as an upper layer parameter (e.g., frequencyDomainAllocation) regarding the frequency domain allocation of CSI-RS.

The bitmap length set/signaled by higher layer parameters may be changeable (or variable) based on predetermined conditions (e.g., the frequency domain density of CSI-RS). For example, when density ρ_new = 1/N or ρ_new = M/N, the bitmap length (or size) signaled by higher layer parameters (e.g., frequencyDomainAllocation) may be extended by a factor of N. In addition, the range of values for kbar/ki may be extended (e.g., [0, N×12-2]).

In addition, bitmap length extension may be supported only for a specific CSI-RS position configuration (e.g., a specific row), only for all rows, or for a new row. The specific row may be, for example, a row other than row #1, row #2, and row #4.

If the bitmap length is extended, the following relationship may be defined for a given row of the table for CSI-RS positions:
[b6*N-1,b6*N-2...b0],k _i-1 =2f(i)
f(i) denotes the number of the i-th bit in the bitmap that is set to 1, and is repeated every N consecutive RBs.

The occupied RB positions (e.g., occupied RB position(s)) indicated/defined in aspect 2-1 may indicate the RB positions of a specific CDM group index (e.g., CDM group index 0). The occupied RB positions may be indicated by higher layer signaling or may be defined for each row.

Here, we show the case where "000000, 100000, 001000, 000010" is specified as the bitmap corresponding to row #x.

The UE selects a row (here, row #x) corresponding to the CSI-RS based on higher layer parameters including a bitmap notified by the base station, and then determines the frequency domain location of the CSI-RS. The UE may determine the row based on the port/density/CDM type notified by the higher layer parameters, or information specifying the row may be notified to the UE by the higher layer parameters.

For row #14, the UE determines that the frequency domain positions of the CSI-RS (each component resource) are k0=2, k1=18, k2=32 based on [b6*N-1, b6*N-2...b0], k _i-1 =2f(i) and the bitmap (000000, 100000, 001000, 000010) (see Figure 14B).

Figure 14B shows an example of a CSI-RS location corresponding to row #14. CSI-RS resources can be mapped across four RBs (here, they are mapped to three RBs). For example, different ports/CDM groups can be mapped to each of the four RBs. Here, CDM groups 0 and 3 are mapped to the first RB, CDM groups 1 and 4 are mapped to the second RB, CDM groups 2 and 5 are mapped to the third RB, and no CSI group is mapped to the fourth RB.

The frequency domain position of the CSI-RS corresponding to CDM groups 0 and 3 is determined based on k0 (= 2). Similarly, the frequency domain position of the CSI-RS corresponding to CDM groups 1 and 4 is determined based on k1 (= 18), and the frequency domain position of the CSI-RS corresponding to CDM groups 2 and 5 is determined based on k2 (= 32). Note that the reference point for ki in the frequency direction may be a specific RB (for example, subcarrier 0 of the RB with the smallest index) among multiple (here, four) RBs.

Figure 14A shows the case where the bitmap length is extended, but it is also possible to have a configuration where the bitmap length is not extended and an offset is added to the k bar (e.g., ki) defined/set in the CSI-RS position configuration (e.g., row) (or the range of the k bar is extended) (see Figure 15A).

In this case, a new row may be introduced in the table related to CSI-RS locations, and the range of kbar/ki in the new row may be defined differently from that of the existing row. For example, 0≦kbar≦12/ρ-1, 0≦ki≦11 may be used. The indicated resource mapping allocation (kbar, lbar) may be repeated in 1/ρ RBs. Higher layer parameters related to frequency domain allocation (e.g., frequencyDomainAllocation) may indicate the location of frequency domain resource allocation in one RB.

Figure 15A shows an example of a CSI-RS resource mapping pattern corresponding to a new row #x. Here, the number of ports is 24, the density is 1/4, and cdm4-FD2-TD2 is shown. It also shows a case where the frequency domain is represented by k0, k1+12, and k2+24. In other words, an offset is added in the frequency direction to the CDM group corresponding to k1 (here, CDM groups 1 and 4) and the CDM group corresponding to k2 (here, CDM groups 2 and 5).

The offset may be a multiple of a predetermined value (e.g., 12). The value of the offset may be determined based on predetermined parameters. For example, the offset value may be determined based on at least one of the CDM type, the number of ports, the frequency domain density, and parameters configured by the RRC.

The network (e.g., base station) may instruct the UE to use a non-expanded bitmap as a higher layer parameter (e.g., frequencyDomainAllocation) for the frequency domain allocation of CSI-RS. For example, a table of CSI-RS locations within a slot including frequency offsets greater than 12 as described above may be added according to a predetermined rule, and the network may determine whether to use the existing table or the added table based on the higher layer parameter. Alternatively, a new row may be added to an existing column, and the row to reference may be determined based on the higher layer parameter. Here, the case where "101010" is instructed as the bitmap corresponding to row #x is shown.

The UE selects a row (here, row #x) corresponding to the CSI-RS based on higher layer parameters including a bitmap notified by the base station, and then determines the frequency domain location of the CSI-RS. The UE may determine the row based on the port/density/CDM type notified by the higher layer parameters, or information specifying the row may be notified to the UE by the higher layer parameters.

For row #x, the UE determines k0=2, k1=6, k2=10 based on [b5...b0], k _i-1 =2f(i) and the bitmap (101010), and determines the frequency domain location of the CSI-RS (each component resource) (see Figure 15B).

Figure 15B shows an example of CSI-RS locations corresponding to row #x. CSI-RS resources can be mapped across four RBs (here, they are mapped to three RBs). For example, different ports/CDM groups can be mapped to each of the four RBs. Here, CDM groups 0 and 3 are mapped to the first RB, CDM groups 1 and 4 are mapped to the second RB, CDM groups 2 and 5 are mapped to the third RB, and no CSI group is mapped to the fourth RB.

The frequency domain location of the CSI-RS corresponding to CDM groups 0 and 3 is determined based on k0 (= 2). The frequency domain location of the CSI-RS corresponding to CDM groups 1 and 4 is determined based on k1 (= 6) + 12. The frequency domain location of the CSI-RS corresponding to CDM groups 2 and 5 is determined based on k2 (= 10) + 24.

In addition, the reference point for ki in the frequency direction may be one of multiple (here, four) RBs (for example, subcarrier 0 of the RB with the smallest index).

In the above explanation, the offset (e.g., 12/24) is based on the subcarrier, but this is not limited to this. For example, in this disclosure, the unit of offset may be RB. For example, the offset added to k1 may be 1 (RB), and the offset added to k2 may be 2 (RB).

In this way, by combining and applying aspects 2-1 and 2-2, it is possible to flexibly control the mapping of CSI-RS resources in the frequency domain and reduce the overhead of CSI-RS resources mapped to the frequency domain.

<<Aspect 2-3>>
When multiple (eg, two) starting symbols are configured within one slot, setting/application of different frequency domain resource allocations to different starting symbols may be supported.

Note that aspect 2-3 may also be applied to CSI-RS position configurations in which multiple starting symbols are set within one slot (e.g., rows #11, #13, #14, #17, or new rows in the table regarding CSI-RS positions).

When multiple start symbols are configured within one slot, it may be supported that the frequency domain resource allocation of CSI-RS resources is configured separately (e.g., differently) for each start symbol.

Figure 16A shows a case where multiple start symbols are configured within one slot, and the frequency domain resource allocation of CSI-RS is configured in common for multiple start symbols (e.g., l0, l1). In Figure 16A, the frequency domain resource allocation of CDM groups 0-2 mapped to the first start symbol and the frequency domain resource allocation of CDM groups 3-5 mapped to the second start symbol are each configured to be the same. Specifically, CDM group 0 mapped to the first start symbol and CDM group 3 mapped to the second start symbol are assigned common frequency domain resources.

On the other hand, Figure 16B shows a case where multiple start symbols are configured within one slot, and the frequency domain resource allocation of CSI-RS is configured separately (e.g., differently) for each start symbol. For example, in Figure 16B, the frequency domain resource allocation for CDM groups 0-2 mapped to the first start symbol and the frequency domain resource allocation for CDM groups 3-5 mapped to the second start symbol are configured separately. Specifically, CDM group 0 mapped to the first start symbol and CDM group 3 mapped to the second start symbol are assigned to different frequency domain resources.

In this way, by performing frequency domain resource allocation separately for different start symbols, it becomes possible to flexibly control the allocation of subcarriers to different ports. Furthermore, in addition to the number of ports supported in existing systems (e.g., 1/2/4/8/12/16/24/32 ports), it becomes possible to support other numbers of ports/port numbers (e.g., 20 ports/28 ports). This makes it possible to set different numbers of CDM groups corresponding to the first start symbol and the second start symbol.

For multiple (e.g., two) starting symbols in one slot, bitmaps corresponding to multiple (e.g., two) frequency domains may be set/indicated/applied. Bitmaps corresponding to multiple frequency domains may be set by higher layer parameters (see Figure 17).

Figure 17 shows an example of higher layer parameters related to CSI-RS resource mapping (e.g., CSI-RS-ResourceMapping). The network (e.g., base station) may use the higher layer parameters related to CSI-RS resource mapping to notify the UE of two frequency domain bitmaps (e.g., frequencyDomainAllocation and frequencyDomainAllocation2).

The UE may apply the notified multiple (e.g., two) frequency domain bitmaps to different start symbols. While Figure 17 shows the case where the size (or bitmap length) of the second bitmap is 6, this is not limited to this and other values may be supported.

The second bitmap (e.g., frequencyDomainAllocation2) may be an additional bitmap added in addition to the first bitmap (e.g., frequencyDomainAllocation). The second bitmap (e.g., frequencyDomainAllocation2) may be present only when a specific CSI-RS location configuration (e.g., row) is configured/indicated. The specific row may be a row in which multiple starting symbols are configured within one slot (e.g., row #13/#14/#16/#17). If the second bitmap is not included when a specific row is configured, the UE may apply the same rules as the CSI-RS resource mapping pattern of the existing system (Rel. 15/16).

Figure 18A shows an example of a CSI-RS resource mapping pattern corresponding to row #14. Here, the cases are shown where the number of ports is 24, 20, and 28, the density is 1, 0.5, and cdm4-FD2-TD2. Also shown is a case where the frequency domains corresponding to the first start symbol (e.g., l0) and the second start symbol (e.g., l1) are indicated by k0, k1, and k2. Note that the number of ports to be set may be specified by higher layer signaling.

The network (e.g., a base station) may notify the UE of a first frequency domain resource allocation (e.g., frequencyDomainAllocation/first bitmap) and a second frequency domain resource allocation (e.g., frequencyDomainAllocation2/second bitmap) as higher layer parameters related to the frequency domain allocation of CSI-RS.

The UE selects a row (here, row #14) corresponding to the CSI-RS based on higher layer parameters including a bitmap notified by the base station, and then determines the frequency domain location of the CSI-RS. The UE may determine the row based on the port/density/CDM type notified by the higher layer parameters, or information specifying the row may be notified to the UE by the higher layer parameters.

The UE determines the frequency domain position (k0, k1, k2) of the CSI-RS (each component resource) in each start symbol based on [b5...b0],k _i-1 =2f(i), the first bitmap, and the second bitmap (see Figures 18B-18D). Figure 18B corresponds to a CSI-RS resource with 24 ports, Figure 18C corresponds to a CSI-RS resource with 20 ports, and Figure 18D corresponds to a CSI-RS resource with 28 ports.

Figure 18B shows a case where "101010" is notified as the first bitmap and "010101" is notified as the second bitmap when the number of ports is 24 (6 CDM groups). In this case, the UE determines that the frequency domain positions of the CSI-RS (each component resource) in the first start symbol are k0 = 2, k1 = 6, k2 = 10. On the other hand, the UE determines that the frequency domain positions of the CSI-RS (each component resource) in the second start symbol are k0 = 0, k1 = 4, k2 = 8.

Figure 18C shows a case where the number of ports is 20 (5 CDM groups), and "101010" is notified as the first bitmap, and "000101" is notified as the second bitmap. In this case, the UE determines that the frequency domain positions of the CSI-RS (each component resource) in the first start symbol are k0 = 2, k1 = 6, and k2 = 10. On the other hand, the UE determines that the frequency domain positions of the CSI-RS (each component resource) in the second start symbol are k0 = 0 and k1 = 4.

Figure 18D shows a case where "101010" is notified as the first bitmap and "101101" is notified as the second bitmap when the number of ports is 28 (7 CDM groups). In this case, the UE determines that the frequency domain positions of the CSI-RS (each component resource) in the first start symbol are k0 = 2, k1 = 6, k2 = 10. On the other hand, the UE determines that the frequency domain positions of the CSI-RS (each component resource) in the second start symbol are k0 = 0, k1 = 4, k2 = 6, k3 = 10.

Figures 18A-D show cases where multiple bitmaps are notified to the UE, but this is not limited to this. It is also possible to define/set k bars (e.g., ki) corresponding to different start symbols separately without notifying the second bitmap (e.g., frequencyDomainAllocation2).

In this case, a new row may be introduced into the table relating to CSI-RS positions, and the definition of k/ki in the new row may be defined differently from that of the existing row. For example, a configuration in which a predetermined offset is added to ki corresponding to the first start symbol may be applied to the second start symbol. The predetermined offset may be obtained by applying a modulo operation, for example.

Figure 19A shows an example of a CSI-RS resource mapping pattern corresponding to a new row #x. Here, the number of ports is 24, the density is 1, 0.5, and cdm4-FD2-TD2. Also shown is a case where the frequency domain corresponding to the first start symbol is defined by k0, k1, and k2, and the frequency domain corresponding to the second start symbol is defined by (k0+2) mod 2, (k1+2) mod 2, and (k2+2) mod 2.

The network (e.g., a base station) may indicate a bitmap to the UE as an upper layer parameter (e.g., frequencyDomainAllocation) related to the frequency domain allocation of CSI-RS. Here, we show the case where "101010" is indicated as the bitmap corresponding to row #x.

The UE selects a row (here, row #x) corresponding to the CSI-RS based on higher layer parameters including a bitmap notified by the base station, and then determines the frequency domain location of the CSI-RS. The UE may determine the row based on the port/density/CDM type notified by the higher layer parameters, or information specifying the row may be notified to the UE by the higher layer parameters.

For row #x, the UE determines k0=2, k1=6, k2=10 based on [b5...b0],k _i-1 =2f(i) and the bitmap (101010), and determines the positions of the frequency domain resources of the CSI-RS (each component resource) (see FIG. 19B ). Here, the positions of the frequency domain resources corresponding to the first start symbol (the frequency domain resources corresponding to CDM groups 0, 1, and 2, respectively) are k0=2, k1=6, and k2=10, and the positions of the frequency domain resources corresponding to the second start symbol (the frequency domain resources corresponding to CDM groups 3, 4, and 5, respectively) are (k0+2)mod12=4, (k1+2)mod12=8, and (k2+2)mod12=0.

In addition, aspect 2-3 may be applied in combination with at least one of aspects 2-1 and 2-2.

<<Aspect 2-2 + Aspect 2-3>>
When the frequency domain density value of the CSI-RS resource is less than 1 and multiple (e.g., two) starting symbols are configured in one slot, different port/CDM group mappings for multiple RBs (or different RBs) may be supported, and different frequency domain resource allocations for different starting symbols may be supported.

Figure 20A shows an example of a CSI-RS resource mapping pattern corresponding to row #14. Here, the number of ports is 24, the densities are 1, 0.5, and cdm4-FD2-TD2. Also shown is a case where the frequency domains corresponding to the first start symbol (e.g., l0) and the second start symbol (e.g., l1) are indicated by k0, k1, and k2. Note that the density of the frequency domains to be set may be specified by higher layer signaling.

The network (e.g., a base station) may notify the UE of a first frequency domain resource allocation (e.g., frequencyDomainAllocation/first bitmap) and a second frequency domain resource allocation (e.g., frequencyDomainAllocation2/second bitmap) as higher layer parameters related to the frequency domain allocation of CSI-RS.

The UE selects a row (here, row #14) corresponding to the CSI-RS based on higher layer parameters including a bitmap notified by the base station, and then determines the frequency domain location of the CSI-RS. The UE may determine the row based on the port/density/CDM type notified by the higher layer parameters, or information specifying the row may be notified to the UE by the higher layer parameters.

When the frequency domain density is 0.5, the UE determines the frequency domain position (k0, k1, k2) of the CSI-RS (each component resource) in each starting symbol based on [b11...b0],k _i-1 =2f(i), the first bitmap, and the second bitmap (see Figure 20B).

Figure 20B shows a case where the number of ports is 24 (6 CDM groups), and "000000101010" is notified as the first bitmap, and "010101000000" is notified as the second bitmap. In this case, the UE determines that the frequency domain positions of the CSI-RS (each component resource) in the first start symbol are k0 = 2, k1 = 6, and k2 = 10. On the other hand, the UE determines that the frequency domain positions of the CSI-RS (each component resource) in the second start symbol are k0 = 12, k1 = 16, and k2 = 20.

Here, we show the case where CDM groups 0, 1, and 2 corresponding to the first starting symbol are mapped to the first RB, and CDM groups 3, 4, and 5 corresponding to the second starting symbol are mapped to the second RB.

In this way, bitmap indication of different frequency domain allocations is supported for different starting symbols, and when the frequency domain density is less than 1, it is possible to map multiple ports with different frequency domain resource allocations to different RBs.

Figures 20A and 20B show a case where multiple bitmaps are notified to the UE, but this is not limited to this. It is also possible to define/set k bars (e.g., ki) corresponding to different start symbols separately without notifying the second bitmap (e.g., frequencyDomainAllocation2).

<<Aspect 2-1 + Aspect 2-2 + Aspect 2-3>>
When a new frequency domain density (e.g., ρ_new = 1/N or M/N) different from that of existing systems is applied as the frequency domain density value of CSI-RS resources and multiple (e.g., two) starting symbols are set within one slot, mapping of different ports/CDM groups to multiple RBs (or different RBs) is supported, and different frequency domain resource allocations may be supported for different starting symbols.

Figure 21A shows an example of a CSI-RS resource mapping pattern corresponding to row #14. Here, the number of ports is 24, and the densities are 1, 0.5, 1/4, and cdm4-FD2-TD2. Also shown is a case where the frequency domains corresponding to the first start symbol (e.g., l0) and the second start symbol (e.g., l1) are indicated by k0, k1, and k2. Note that the density of the frequency domains to be set may be specified by higher layer signaling.

The network (e.g., a base station) may notify the UE of a first frequency domain resource allocation (e.g., frequencyDomainAllocation/first bitmap) and a second frequency domain resource allocation (e.g., frequencyDomainAllocation2/second bitmap) as higher layer parameters related to the frequency domain allocation of CSI-RS.

The UE selects a row (here, row #14) corresponding to the CSI-RS based on higher layer parameters including a bitmap notified by the base station, and then determines the frequency domain location of the CSI-RS. The UE may determine the row based on the port/density/CDM type notified by the higher layer parameters, or information specifying the row may be notified to the UE by the higher layer parameters.

When the frequency domain density is 1/4, the UE determines the frequency domain position (k0, _{k1, k2) of the CSI-RS (each component resource) in each starting symbol based on [b6*N-1, b6*N-2...b0],k i-1} =2f(i), the first bitmap, and the second bitmap (see Figure 21B).

Figure 21B shows a case where the number of ports is 24 (6 CDM groups), and "000000, 100000, 001000, 000010" is notified as the first bitmap, and "100000, 000001, 000000, 100000" is notified as the second bitmap. In this case, the UE determines that the frequency domain positions of the CSI-RS (each component resource) in the first start symbol are k0 = 2, k1 = 18, k2 = 34. On the other hand, the UE determines that the frequency domain positions of the CSI-RS (each component resource) in the second start symbol are k0 = 10, k1 = 24, k2 = 46.

Here, CDM groups 0, 1, and 2 corresponding to the first start symbol are mapped to different RBs, and CDM groups 3, 4, and 5 corresponding to the second start symbol are mapped to different RBs. Furthermore, the frequency domain resources for CDM groups 0, 1, and 2 corresponding to the first start symbol and the frequency domain resources for CDM groups 3, 4, and 5 corresponding to the second start symbol are configured separately.

In this way, different frequency domain resource allocations are supported for different starting symbols (or for each starting symbol), and when the frequency domain density is less than 1 (e.g., ρ_new = 1/N or M/N), it is possible to map multiple ports with different frequency domain resource allocations to different RBs.

Figures 21A and 21B show a case where multiple bitmaps are notified to the UE, but this is not limited to this. It is also possible to define/set k bars (e.g., ki) corresponding to different start symbols separately without notifying the second bitmap (e.g., frequencyDomainAllocation2).

Which of Aspects 2-1 to 2-3 is applied may be configured in the UE by higher layer parameters, may be reported by the UE as UE capability information, or may be defined by specifications. Alternatively, which of Aspects 2-1 to 2-3 is applied may be determined taking into account the UE capability information reported by the UE and the higher layer parameters configured in the UE.

(UE capability information)
In the first and second embodiments, the following UE capabilities may be configured. Note that the following UE capabilities may be interpreted as parameters (e.g., upper layer parameters) configured in the UE from a network (e.g., a base station).

The operations of each embodiment may only be applied if the corresponding UE capabilities are reported.

UE capability information may be defined regarding whether or not the time domain periodicity of CSI-RS supports values greater than a predetermined value.

UE capability information may be defined regarding whether or not a predetermined value (e.g., a new value not supported in existing systems) is supported for the frequency domain density of CSI-RS.

UE capability information may be defined regarding whether the UE supports mapping different ports/CDM groups to different RBs.

The first and second embodiments may be configured to be applied to a UE that supports/reports at least one of the above-mentioned UE capabilities. Alternatively, the above embodiments may be configured to be applied to a UE configured by the network.

(wireless communication system)
The configuration of a wireless communication system according to an embodiment of the present disclosure will be described below. In this wireless communication system, communication is performed using any one of the wireless communication methods according to the above embodiments of the present disclosure or a combination thereof.

Figure 22 is a diagram showing an example of the schematic configuration of a wireless communication system according to one embodiment. The wireless communication system 1 may be a system that realizes communication using Long Term Evolution (LTE) specified by the Third Generation Partnership Project (3GPP), 5th generation mobile communication system New Radio (5G NR), or the like.

The wireless communication system 1 may also support dual connectivity between multiple Radio Access Technologies (RATs) (Multi-RAT Dual Connectivity (MR-DC)). MR-DC may include dual connectivity between LTE (Evolved Universal Terrestrial Radio Access (E-UTRA)) and NR (E-UTRA-NR Dual Connectivity (EN-DC)), dual connectivity between NR and LTE (NR-E-UTRA Dual Connectivity (NE-DC)), etc.

In EN-DC, the LTE (E-UTRA) base station (eNB) is the master node (MN), and the NR base station (gNB) is the secondary node (SN). In NE-DC, the NR base station (gNB) is the MN, and the LTE (E-UTRA) base station (eNB) is the SN.

The wireless communication system 1 may support dual connectivity between multiple base stations within the same RAT (e.g., dual connectivity in which both the MN and SN are NR base stations (gNBs) (NR-NR Dual Connectivity (NN-DC))).

The wireless communication system 1 may include a base station 11 that forms a macrocell C1 with relatively wide coverage, and base stations 12 (12a-12c) that are located within the macrocell C1 and form a small cell C2 that is smaller than the macrocell C1. A user terminal 20 may be located within at least one of the cells. The location and number of each cell and user terminal 20 are not limited to the configuration shown in the figure. Hereinafter, when there is no need to distinguish between base stations 11 and 12, they will be collectively referred to as base station 10.

The user terminal 20 may be connected to at least one of the multiple base stations 10. The user terminal 20 may utilize at least one of carrier aggregation (CA) using multiple component carriers (CC) and dual connectivity (DC).

Each CC may be included in at least one of a first frequency band (Frequency Range 1 (FR1)) and a second frequency band (Frequency Range 2 (FR2)). Macro cell C1 may be included in FR1, and small cell C2 may be included in FR2. For example, FR1 may be a frequency band below 6 GHz (sub-6 GHz), and FR2 may be a frequency band above 24 GHz (above-24 GHz). Note that the frequency bands and definitions of FR1 and FR2 are not limited to these, and for example, FR1 may correspond to a higher frequency band than FR2.

In addition, the user terminal 20 may communicate using at least one of Time Division Duplex (TDD) and Frequency Division Duplex (FDD) in each CC.

Multiple base stations 10 may be connected by wire (e.g., optical fiber compliant with the Common Public Radio Interface (CPRI), X2 interface, etc.) or wirelessly (e.g., NR communication). For example, when NR communication is used as a backhaul between base stations 11 and 12, base station 11, which corresponds to the upper station, may be called an Integrated Access Backhaul (IAB) donor, and base station 12, which corresponds to the relay station, may be called an IAB node.

A base station 10 may be connected to a core network 30 via another base station 10 or directly. The core network 30 may include, for example, at least one of an Evolved Packet Core (EPC), a 5G Core Network (5GCN), a Next Generation Core (NGC), etc.

The user terminal 20 may be a terminal compatible with at least one of the communication methods such as LTE, LTE-A, and 5G.

In the wireless communication system 1, a wireless access method based on Orthogonal Frequency Division Multiplexing (OFDM) may be used. For example, in at least one of the downlink (DL) and uplink (UL), Cyclic Prefix OFDM (CP-OFDM), Discrete Fourier Transform Spread OFDM (DFT-s-OFDM), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), etc. may be used.

A radio access method may also be called a waveform. In wireless communication system 1, other radio access methods (e.g., other single-carrier transmission methods, other multi-carrier transmission methods) may be used for the UL and DL radio access methods.

In the wireless communication system 1, a downlink shared channel (Physical Downlink Shared Channel (PDSCH)) shared by each user terminal 20, a broadcast channel (Physical Broadcast Channel (PBCH)), a downlink control channel (Physical Downlink Control Channel (PDCCH)), etc. may be used as a downlink channel.

In addition, in the wireless communication system 1, an uplink shared channel (Physical Uplink Shared Channel (PUSCH)) shared by each user terminal 20, an uplink control channel (Physical Uplink Control Channel (PUCCH)), a random access channel (Physical Random Access Channel (PRACH)), etc. may be used as an uplink channel.

User data, upper layer control information, System Information Block (SIB), etc. are transmitted via PDSCH. User data, upper layer control information, etc. may also be transmitted via PUSCH. Furthermore, Master Information Block (MIB) may also be transmitted via PBCH.

Lower layer control information may be transmitted via the PDCCH. The lower layer control information may include, for example, Downlink Control Information (DCI) including scheduling information for at least one of the PDSCH and the PUSCH.

Note that the DCI that schedules the PDSCH may be called a DL assignment, DL DCI, etc., and the DCI that schedules the PUSCH may be called an UL grant, UL DCI, etc. Note that the PDSCH may be interpreted as DL data, and the PUSCH may be interpreted as UL data.

Detection of the PDCCH may utilize a control resource set (CORESET) and a search space. The CORESET corresponds to the resources to search for DCI. The search space corresponds to the search region and search method for PDCCH candidates. One CORESET may be associated with one or more search spaces. The UE may monitor the CORESET associated with a certain search space based on the search space configuration.

One search space may correspond to PDCCH candidates corresponding to one or more aggregation levels. One or more search spaces may be referred to as a search space set. Note that the terms "search space," "search space set," "search space setting," "search space set setting," "CORESET," "CORESET setting," etc. in the present disclosure may be read interchangeably.

The PUCCH may transmit uplink control information (UCI) including at least one of channel state information (CSI), delivery confirmation information (which may be referred to as, for example, Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK), ACK/NACK, etc.), and scheduling request (SR). The PRACH may transmit a random access preamble for establishing a connection with a cell.

Note that in this disclosure, downlink, uplink, etc. may be expressed without the word "link." Also, various channels may be expressed without the word "Physical" at the beginning.

In the wireless communication system 1, a synchronization signal (SS), a downlink reference signal (DL-RS), etc. may be transmitted. In the wireless communication system 1, a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS), a demodulation reference signal (DMRS), a positioning reference signal (PRS), a phase tracking reference signal (PTRS), etc. may be transmitted as the DL-RS.

The synchronization signal may be, for example, at least one of a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS). A signal block including an SS (PSS, SSS) and a PBCH (and a DMRS for the PBCH) may be referred to as an SS/PBCH block, an SS Block (SSB), etc. Note that SS, SSB, etc. may also be referred to as a reference signal.

In addition, in the wireless communication system 1, a sounding reference signal (SRS), a demodulation reference signal (DMRS), etc. may be transmitted as an uplink reference signal (UL-RS). DMRS may also be called a user equipment-specific reference signal (UE-specific Reference Signal).

(base station)
23 is a diagram showing an example of the configuration of a base station according to an embodiment. The base station 10 includes a control unit 110, a transceiver unit 120, a transceiver antenna 130, and a transmission line interface 140. Note that the base station may include one or more of each of the control unit 110, the transceiver unit 120, the transceiver antenna 130, and the transmission line interface 140.

Note that this example mainly shows the functional blocks that characterize this embodiment, and the base station 10 may also have other functional blocks necessary for wireless communication. Some of the processing of each unit described below may be omitted.

The control unit 110 controls the entire base station 10. The control unit 110 can be composed of a controller, a control circuit, etc., which are described based on common understanding in the technical field related to this disclosure.

The control unit 110 may control signal generation, scheduling (e.g., resource allocation, mapping), etc. The control unit 110 may also control transmission and reception using the transceiver unit 120, the transceiver antenna 130, and the transmission path interface 140, measurements, etc. The control unit 110 may generate data, control information, sequences, etc. to be transmitted as signals and transfer them to the transceiver unit 120. The control unit 110 may also perform call processing of communication channels (setting up, releasing, etc.), status management of the base station 10, management of radio resources, etc.

The transceiver unit 120 may include a baseband unit 121, a radio frequency (RF) unit 122, and a measurement unit 123. The baseband unit 121 may include a transmission processing unit 1211 and a reception processing unit 1212. The transceiver unit 120 may be composed of a transmitter/receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transceiver circuit, etc., which are described based on common understanding in the technical field related to the present disclosure.

The transmitter/receiver unit 120 may be configured as an integrated transmitter/receiver unit, or may be composed of a transmitter unit and a receiver unit. The transmitter unit may be composed of a transmission processing unit 1211 and an RF unit 122. The receiver unit may be composed of a reception processing unit 1212, an RF unit 122, and a measurement unit 123.

The transmitting and receiving antenna 130 may be composed of an antenna described based on common understanding in the technical field to which this disclosure relates, such as an array antenna.

The transceiver 120 may transmit the above-mentioned downlink channel, synchronization signal, downlink reference signal, etc. The transceiver 120 may receive the above-mentioned uplink channel, uplink reference signal, etc.

The transceiver unit 120 may form at least one of the transmit beam and the receive beam using digital beamforming (e.g., precoding), analog beamforming (e.g., phase rotation), etc.

The transceiver unit 120 (transmission processing unit 1211) may perform Packet Data Convergence Protocol (PDCP) layer processing, Radio Link Control (RLC) layer processing (e.g., RLC retransmission control), Medium Access Control (MAC) layer processing (e.g., HARQ retransmission control), etc. on data, control information, etc. obtained from the control unit 110, and generate a bit string to be transmitted.

The transmitter/receiver unit 120 (transmission processing unit 1211) may perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filtering, Discrete Fourier Transform (DFT) processing (if necessary), Inverse Fast Fourier Transform (IFFT) processing, precoding, and digital-to-analog conversion on the bit sequence to be transmitted, and output a baseband signal.

The transceiver unit 120 (RF unit 122) may perform modulation, filtering, amplification, etc. on the baseband signal to a radio frequency band, and transmit the radio frequency band signal via the transceiver antenna 130.

On the other hand, the transceiver unit 120 (RF unit 122) may perform amplification, filtering, demodulation to a baseband signal, etc. on the radio frequency band signal received by the transceiver antenna 130.

The transceiver unit 120 (receiving processing unit 1212) may apply receiving processing such as analog-to-digital conversion, Fast Fourier Transform (FFT) processing, Inverse Discrete Fourier Transform (IDFT) processing (if necessary), filtering, demapping, demodulation, decoding (which may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the acquired baseband signal, thereby acquiring user data, etc.

The transceiver unit 120 (measurement unit 123) may perform measurements on the received signal. For example, the measurement unit 123 may perform Radio Resource Management (RRM) measurements, Channel State Information (CSI) measurements, etc. based on the received signal. The measurement unit 123 may measure received power (e.g., Reference Signal Received Power (RSRP)), received quality (e.g., Reference Signal Received Quality (RSRQ), Signal to Interference plus Noise Ratio (SINR), Signal to Noise Ratio (SNR)), signal strength (e.g., Received Signal Strength Indicator (RSSI)), propagation path information (e.g., CSI), etc. The measurement results may be output to the control unit 110.

The transmission path interface 140 may send and receive signals (backhaul signaling) between devices included in the core network 30, other base stations 10, etc., and may acquire and transmit user data (user plane data), control plane data, etc. for the user terminal 20.

In addition, the transmitting unit and receiving unit of the base station 10 in the present disclosure may be composed of at least one of the transmitting/receiving unit 120, the transmitting/receiving antenna 130, and the transmission path interface 140.

The transceiver unit 120 may transmit, for the channel state information reference signal, at least one of information regarding time domain resources indicated in time units longer than a slot and information regarding frequency domain resources supporting a frequency domain density at least less than 0.5. The control unit 110 may control mapping of the channel state information reference signal corresponding to at least one of the information regarding time domain resources and the information regarding frequency domain resources.

Alternatively, the transceiver unit 120 may transmit information regarding the frequency domain density of the channel state information reference signal. When the frequency domain density is less than 1, the control unit 110 may control the transmission of a channel state information reference signal in which at least one mapping of different ports and different CDM groups is supported for multiple resource blocks.

Alternatively, the transceiver unit 120 may transmit information regarding the start symbol of the channel state information reference signal. When multiple start symbols are included in a slot, the control unit 110 may control the transmission of a channel state information reference signal in which frequency domain resources are set separately for each start symbol.

(user terminal)
24 is a diagram showing an example of the configuration of a user terminal according to one embodiment. The user terminal 20 includes a control unit 210, a transceiver unit 220, and a transceiver antenna 230. Note that the user terminal 20 may include one or more of each of the control unit 210, the transceiver unit 220, and the transceiver antenna 230.

Note that this example mainly shows the functional blocks of the characteristic parts of this embodiment, and it may be assumed that the user terminal 20 also has other functional blocks necessary for wireless communication. Some of the processing of each part described below may be omitted.

The control unit 210 controls the entire user terminal 20. The control unit 210 can be composed of a controller, a control circuit, etc., which are described based on common understanding in the technical field to which this disclosure relates.

The control unit 210 may control signal generation, mapping, etc. The control unit 210 may control transmission and reception, measurement, etc. using the transceiver unit 220 and the transceiver antenna 230. The control unit 210 may generate data, control information, sequences, etc. to be transmitted as signals and transfer them to the transceiver unit 220.

The transceiver unit 220 may include a baseband unit 221, an RF unit 222, and a measurement unit 223. The baseband unit 221 may include a transmission processing unit 2211 and a reception processing unit 2212. The transceiver unit 220 may be composed of a transmitter/receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transceiver circuit, etc., which are described based on common understanding in the technical field related to the present disclosure.

The transmitter/receiver unit 220 may be configured as an integrated transmitter/receiver unit, or may be composed of a transmitter unit and a receiver unit. The transmitter unit may be composed of a transmission processing unit 2211 and an RF unit 222. The receiver unit may be composed of a reception processing unit 2212, an RF unit 222, and a measurement unit 223.

The transmitting/receiving antenna 230 may be composed of an antenna described based on common understanding in the technical field to which this disclosure relates, such as an array antenna.

The transceiver unit 220 may receive the above-mentioned downlink channel, synchronization signal, downlink reference signal, etc. The transceiver unit 220 may transmit the above-mentioned uplink channel, uplink reference signal, etc.

The transceiver unit 220 may form at least one of the transmit beam and the receive beam using digital beamforming (e.g., precoding), analog beamforming (e.g., phase rotation), etc.

The transceiver unit 220 (transmission processing unit 2211) may perform PDCP layer processing, RLC layer processing (e.g., RLC retransmission control), MAC layer processing (e.g., HARQ retransmission control), etc. on data, control information, etc. obtained from the control unit 210, and generate a bit string to be transmitted.

The transceiver unit 220 (transmission processing unit 2211) may perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filtering, DFT processing (if necessary), IFFT processing, precoding, and digital-to-analog conversion on the bit sequence to be transmitted, and output a baseband signal.

Whether or not to apply DFT processing may be based on the settings of transform precoding. If transform precoding is enabled for a certain channel (e.g., PUSCH), the transceiver unit 220 (transmission processing unit 2211) may perform DFT processing as the transmission processing to transmit the channel using a DFT-s-OFDM waveform; if not, it may not be necessary to perform DFT processing as the transmission processing.

The transceiver unit 220 (RF unit 222) may perform modulation, filtering, amplification, etc. on the baseband signal to a radio frequency band, and transmit the radio frequency band signal via the transceiver antenna 230.

On the other hand, the transceiver unit 220 (RF unit 222) may perform amplification, filtering, demodulation to a baseband signal, etc. on the radio frequency band signal received by the transceiver antenna 230.

The transceiver unit 220 (receiving processing unit 2212) may apply receiving processing such as analog-to-digital conversion, FFT processing, IDFT processing (if necessary), filtering, demapping, demodulation, decoding (which may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the acquired baseband signal to acquire user data, etc.

The transceiver unit 220 (measurement unit 223) may perform measurements on the received signal. For example, the measurement unit 223 may perform RRM measurements, CSI measurements, etc. based on the received signal. The measurement unit 223 may measure received power (e.g., RSRP), received quality (e.g., RSRQ, SINR, SNR), signal strength (e.g., RSSI), propagation path information (e.g., CSI), etc. The measurement results may be output to the control unit 210.

In addition, the transmitting unit and receiving unit of the user terminal 20 in the present disclosure may be constituted by at least one of the transmitting/receiving unit 220 and the transmitting/receiving antenna 230.

The transceiver unit 220 may receive, for the channel state information reference signal, at least one of information regarding time domain resources indicated in time units longer than a slot and information regarding frequency domain resources supporting a frequency domain density of at least less than 0.5. The control unit 210 may control reception of the channel state information reference signal based on at least one of the information regarding time domain resources and the information regarding frequency domain resources (aspect 2-1 of the first embodiment/second embodiment).

The information regarding the time domain resource may include information regarding an offset indicated in a time unit longer than a slot. The information regarding the frequency domain resource may include information regarding one or more resource blocks to which the channel state information reference signal is assigned among a plurality of resource blocks. The information regarding one or more resource blocks to which the channel state information reference signal is assigned may be indicated in a bitmap format.

Alternatively, the transceiver unit 220 may receive information regarding the frequency domain density of the channel state information reference signal. When the frequency domain density is less than 1, the control unit 210 may control the reception of a channel state information reference signal in which at least one mapping of different ports and different CDM groups is supported for multiple resource blocks (aspect 2-2 of the second embodiment).

The transceiver unit 220 may receive frequency domain allocation information of the channel state reference signal including a bitmap indicating subcarriers in multiple resource blocks. The size of the bitmap may be variable depending on the frequency domain density. The transceiver unit 220 may receive the frequency domain allocation information of the channel state reference signal, and the control unit 210 may control reception of the channel state information reference signal by applying a predetermined offset to the frequency domain allocation information of the channel state reference signal.

Alternatively, the transceiver unit 220 may receive information regarding the start symbol of the channel state information reference signal. When multiple start symbols are included in a slot, the control unit 210 may control the reception of a channel state information reference signal in which frequency domain resources are set separately for each start symbol (aspect 2-3 of the second embodiment).

The transceiver unit 220 may receive multiple bitmaps indicating frequency domain allocations of channel state information corresponding to each start symbol. When a slot includes a first start symbol and a second start symbol, a predetermined offset may be applied to the frequency domain position of the channel state reference signal corresponding to the second start symbol relative to the frequency domain position of the channel state reference signal corresponding to the first start symbol. The number of CDM groups mapped to each start symbol may be set differently.

(Hardware configuration)
The block diagrams used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of hardware and/or software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are directly or indirectly connected (e.g., wired, wireless, etc.) and these multiple devices. The functional block may also be realized by combining software with the single device or multiple devices.

Here, functions include, but are not limited to, judgment, determination, assessment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, establishment, comparison, assumption, expectation, deeming, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission functions may be called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on how these functions are implemented.

For example, a base station, a user terminal, etc. in one embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Figure 25 is a diagram showing an example of the hardware configuration of a base station and a user terminal according to one embodiment. The above-mentioned base station 10 and user terminal 20 may be physically configured as a computer device including a processor 1001, memory 1002, storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

In this disclosure, terms such as apparatus, circuit, device, section, and unit may be used interchangeably. The hardware configuration of the base station 10 and user terminal 20 may be configured to include one or more of the devices shown in the figures, or may be configured to exclude some of the devices.

For example, although only one processor 1001 is shown, there may be multiple processors. Furthermore, processing may be performed by one processor, or processing may be performed by two or more processors simultaneously, sequentially, or using other techniques. Furthermore, processor 1001 may be implemented by one or more chips.

Each function in the base station 10 and the user terminal 20 is realized, for example, by loading specified software (programs) onto hardware such as the processor 1001 and memory 1002, causing the processor 1001 to perform calculations, control communication via the communication device 1004, and control at least one of reading and writing data in the memory 1002 and storage 1003.

The processor 1001, for example, runs an operating system to control the entire computer. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control unit, an arithmetic unit, registers, etc. For example, at least a portion of the above-mentioned control unit 110 (210), transceiver unit 120 (220), etc. may be realized by the processor 1001.

The processor 1001 also reads programs (program code), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002, and executes various processes in accordance with these. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 110 (210) may be realized by a control program stored in the memory 1002 and running on the processor 1001, and similar implementations may be used for other functional blocks.

Memory 1002 is a computer-readable recording medium and may be composed of, for example, at least one of Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically EEPROM (EEPROM), Random Access Memory (RAM), or other suitable storage medium. Memory 1002 may also be referred to as a register, cache, main memory, etc. Memory 1002 may store executable programs (program code), software modules, etc. for implementing a wireless communication method according to one embodiment of the present disclosure.

Storage 1003 is a computer-readable recording medium and may be constituted by at least one of, for example, a flexible disk, a floppy disk, a magneto-optical disk (e.g., a compact disk (e.g., a Compact Disc ROM (CD-ROM)), a digital versatile disk, a Blu-ray disc), a removable disk, a hard disk drive, a smart card, a flash memory device (e.g., a card, stick, key drive), a magnetic stripe, a database, a server, or other suitable storage medium. Storage 1003 may also be referred to as an auxiliary storage device.

The communication device 1004 is hardware (transmitting/receiving device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as a network device, network controller, network card, or communication module. The communication device 1004 may be configured to include a high-frequency switch, duplexer, filter, frequency synthesizer, etc. to implement at least one of Frequency Division Duplex (FDD) and Time Division Duplex (TDD). For example, the above-mentioned transmitter/receiver unit 120 (220), transmitter/receiver antenna 130 (230), etc. may be implemented by the communication device 1004. The transmitter/receiver unit 120 (220) may be implemented as a transmitter unit 120a (220a) and a receiver unit 120b (220b) that are physically or logically separated.

The input device 1005 is an input device (e.g., a keyboard, mouse, microphone, switch, button, sensor, etc.) that accepts input from the outside. The output device 1006 is an output device (e.g., a display, speaker, Light Emitting Diode (LED) lamp, etc.) that outputs to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one structure (e.g., a touch panel).

Furthermore, each device such as the processor 1001 and memory 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

Furthermore, the base station 10 and the user terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized using such hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

(Modification)
Note that terms described in the present disclosure and terms necessary for understanding the present disclosure may be replaced with terms having the same or similar meanings. For example, a channel, a symbol, and a signal (signal or signaling) may be interchangeable. A signal may also be a message. A reference signal may be abbreviated as RS, and may also be called a pilot, pilot signal, etc. depending on the applicable standard. A component carrier (CC) may also be called a cell, frequency carrier, carrier frequency, etc.

A radio frame may be composed of one or more periods (frames) in the time domain. Each of the one or more periods (frames) constituting a radio frame may be called a subframe. Furthermore, a subframe may be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

Here, numerology may be a communication parameter applied to at least one of the transmission and reception of a signal or channel. Numerology may indicate, for example, at least one of subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, specific filtering operations performed by the transceiver in the frequency domain, and specific windowing operations performed by the transceiver in the time domain.

A slot may consist of one or more symbols in the time domain (such as Orthogonal Frequency Division Multiplexing (OFDM) symbols or Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols). A slot may also be a time unit based on numerology.

A slot may include multiple minislots. Each minislot may consist of one or more symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (PUSCH) mapping type B.

Radio frame, subframe, slot, minislot, and symbol all represent time units for transmitting signals. Radio frame, subframe, slot, minislot, and symbol may be referred to by other names that correspond to them. Note that the time units such as frame, subframe, slot, minislot, and symbol used in this disclosure may be interpreted interchangeably.

For example, one subframe may be referred to as a TTI, multiple consecutive subframes may be referred to as a TTI, or one slot or one minislot may be referred to as a TTI. In other words, at least one of a subframe and a TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (e.g., 1-13 symbols), or a period longer than 1 ms. Note that the unit representing a TTI may be called a slot, minislot, etc. instead of a subframe.

Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station schedules each user terminal by allocating radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) in TTI units. Note that the definition of TTI is not limited to this.

A TTI may be a transmission time unit for a channel-coded data packet (transport block), code block, code word, etc., or may be a processing unit for scheduling, link adaptation, etc. Note that when a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, code block, code word, etc. is actually mapped may be shorter than the TTI.

Note that when one slot or one minislot is referred to as a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the smallest time unit for scheduling. Furthermore, the number of slots (minislots) constituting the smallest time unit for scheduling may be controlled.

A TTI with a time length of 1 ms may be referred to as a regular TTI (TTI in 3GPP Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be referred to as a shortened TTI, short TTI, partial TTI (partial or fractional TTI), shortened subframe, short subframe, minislot, subslot, slot, etc.

Note that a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than that of a long TTI and greater than or equal to 1 ms.

A resource block (RB) is a resource allocation unit in the time domain and frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of numerology, for example, 12. The number of subcarriers included in an RB may also be determined based on numerology.

In addition, an RB may include one or more symbols in the time domain and may be one slot, one minislot, one subframe, or one TTI in length. One TTI, one subframe, etc. may each be composed of one or more resource blocks.

In addition, one or more RBs may also be referred to as a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

A resource block may also be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

A Bandwidth Part (BWP) (which may also be referred to as a partial bandwidth) may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by their index relative to a Common Reference Point of the carrier. PRBs may be defined in a BWP and numbered within that BWP.

BWPs may include UL BWPs (BWPs for UL) and DL BWPs (BWPs for DL). One or more BWPs may be configured for a UE within one carrier.

At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a given signal/channel outside the active BWP. Note that the terms "cell," "carrier," etc. in this disclosure may be read as "BWP."

Note that the structures of the radio frames, subframes, slots, minislots, and symbols described above are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, as well as the number of symbols in a TTI, symbol length, and cyclic prefix (CP) length can be varied in various ways.

Furthermore, the information, parameters, etc. described in this disclosure may be expressed using absolute values, relative values from a predetermined value, or other corresponding information. For example, radio resources may be indicated by a predetermined index.

The names used for parameters and the like in this disclosure are not intended to be limiting in any way. Furthermore, the mathematical formulas and the like using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

In addition, information, signals, etc. may be output from a higher layer to a lower layer and/or from a lower layer to a higher layer. Information, signals, etc. may be input/output via multiple network nodes.

Input and output information, signals, etc. may be stored in a specific location (e.g., memory) or managed using a management table. Input and output information, signals, etc. may be overwritten, updated, or added to. Output information, signals, etc. may be deleted. Input information, signals, etc. may be transmitted to another device.

The notification of information is not limited to the aspects/embodiments described in the present disclosure and may be performed using other methods. For example, the notification of information in the present disclosure may be performed by physical layer signaling (e.g., Downlink Control Information (DCI) and Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, broadcast information (Master Information Block (MIB) and System Information Block (SIB)), Medium Access Control (MAC) signaling), other signals, or a combination thereof.

Note that physical layer signaling may also be referred to as Layer 1/Layer 2 (L1/L2) control information (L1/L2 control signal), L1 control information (L1 control signal), etc. Furthermore, RRC signaling may also be referred to as RRC messages, such as RRC Connection Setup messages and RRC Connection Reconfiguration messages. Furthermore, MAC signaling may also be notified using, for example, MAC Control Elements (CEs).

Furthermore, notification of specified information (e.g., notification that "it is X") is not limited to explicit notification, but may also be made implicitly (e.g., by not notifying the specified information or by notifying other information).

The determination may be made by a value represented by a single bit (0 or 1), by a Boolean value represented by true or false, or by a numerical comparison (e.g., comparison with a predetermined value).

Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

Software, instructions, information, etc. may also be transmitted and received via a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and/or wireless technologies (such as infrared, microwave), these wired and/or wireless technologies are included within the definition of transmission media.

As used in this disclosure, the terms "system" and "network" may be used interchangeably. "Network" may refer to devices included in the network (e.g., base stations).

In this disclosure, terms such as "precoding," "precoder," "weight (precoding weight)," "Quasi-Co-Location (QCL)," "Transmission Configuration Indication state (TCI state)," "spatial relation," "spatial domain filter," "transmit power," "phase rotation," "antenna port," "antenna port group," "layer," "number of layers," "rank," "resource," "resource set," "resource group," "beam," "beam width," "beam angle," "antenna," "antenna element," and "panel" may be used interchangeably.

In this disclosure, terms such as "Base Station (BS)," "Radio Base Station," "Fixed Station," "NodeB," "eNB (eNodeB)," "gNB (gNodeB)," "Access Point," "Transmission Point (TP)," "Reception Point (RP)," "Transmission/Reception Point (TRP)," "Panel," "Cell," "Sector," "Cell Group," "Carrier," and "Component Carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the entire coverage area of the base station can be divided into multiple smaller areas, and each smaller area can also be provided with communication services by a base station subsystem (e.g., a small indoor base station (Remote Radio Head (RRH))). The terms "cell" or "sector" refer to part or all of the coverage area of a base station and/or base station subsystem that provides communication services within this coverage area.

In this disclosure, terms such as "Mobile Station (MS)," "user terminal," "User Equipment (UE)," and "terminal" may be used interchangeably.

A mobile station may also be referred to as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

At least one of the base station and the mobile station may be referred to as a transmitting device, a receiving device, a wireless communication device, etc. Note that at least one of the base station and the mobile station may be a device mounted on a moving object, the moving object itself, etc.

The term "mobile body" refers to a movable object that can move at any speed and naturally includes cases where the mobile body is stationary. Examples of such mobile bodies include, but are not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcarts, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones, multicopters, quadcopters, balloons, and objects carried by these. Furthermore, the mobile body may be a mobile body that moves autonomously based on operational commands.

The mobile object may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, a self-driving car, etc.), or a robot (manned or unmanned). Note that at least one of the base station and the mobile station may also include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor.

Figure 26 is a diagram showing an example of a vehicle according to one embodiment. The vehicle 40 includes a drive unit 41, a steering unit 42, an accelerator pedal 43, a brake pedal 44, a shift lever 45, left and right front wheels 46, left and right rear wheels 47, an axle 48, an electronic control unit 49, various sensors (including a current sensor 50, an RPM sensor 51, an air pressure sensor 52, a vehicle speed sensor 53, an acceleration sensor 54, an accelerator pedal sensor 55, a brake pedal sensor 56, a shift lever sensor 57, and an object detection sensor 58), an information service unit 59, and a communication module 60.

The drive unit 41 is composed of, for example, at least one of an engine, a motor, or a hybrid of an engine and a motor. The steering unit 42 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels 46 and the rear wheels 47 based on the operation of the steering wheel operated by the user.

The electronic control unit 49 is composed of a microprocessor 61, memory (ROM, RAM) 62, and a communication port (e.g., an input/output (IO) port) 63. Signals are input to the electronic control unit 49 from various sensors 50-58 provided in the vehicle. The electronic control unit 49 may also be called an Electronic Control Unit (ECU).

Signals from the various sensors 50-58 include a current signal from a current sensor 50 that senses the motor current, a rotation speed signal for the front wheels 46/rear wheels 47 obtained by a rotation speed sensor 51, an air pressure signal for the front wheels 46/rear wheels 47 obtained by an air pressure sensor 52, a vehicle speed signal obtained by a vehicle speed sensor 53, an acceleration signal obtained by an acceleration sensor 54, a depression amount signal for the accelerator pedal 43 obtained by an accelerator pedal sensor 55, a depression amount signal for the brake pedal 44 obtained by a brake pedal sensor 56, an operation signal for the shift lever 45 obtained by a shift lever sensor 57, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 58.

The information service unit 59 is composed of various devices, such as a car navigation system, audio system, speakers, displays, televisions, and radios, for providing (outputting) various information such as driving information, traffic information, and entertainment information, as well as one or more ECUs that control these devices. The information service unit 59 uses information obtained from external devices via the communication module 60, etc., to provide various information/services (e.g., multimedia information/multimedia services) to the occupants of the vehicle 40.

The information service unit 59 may include input devices (e.g., keyboards, mice, microphones, switches, buttons, sensors, touch panels, etc.) that accept input from the outside, and may also include output devices (e.g., displays, speakers, LED lamps, touch panels, etc.) that output to the outside.

The driving assistance system unit 64 is composed of various devices that provide functions to prevent accidents and reduce the driver's driving burden, such as millimeter-wave radar, Light Detection and Ranging (LiDAR), cameras, positioning locators (e.g., Global Navigation Satellite System (GNSS)), map information (e.g., High Definition (HD) maps, Autonomous Vehicle (AV) maps), gyro systems (e.g., Inertial Measurement Unit (IMU) and Inertial Navigation System (INS)), artificial intelligence (AI) chips, and AI processors, as well as one or more ECUs that control these devices. The driving assistance system unit 64 also transmits and receives various information via the communication module 60 to realize driving assistance or autonomous driving functions.

The communication module 60 can communicate with the microprocessor 61 and components of the vehicle 40 via the communication port 63. For example, the communication module 60 transmits and receives data (information) via the communication port 63 between the drive unit 41, steering unit 42, accelerator pedal 43, brake pedal 44, shift lever 45, left and right front wheels 46, left and right rear wheels 47, axles 48, the microprocessor 61 and memory (ROM, RAM) 62 in the electronic control unit 49, and various sensors 50-58, all of which are provided on the vehicle 40.

The communication module 60 is a communication device that can be controlled by the microprocessor 61 of the electronic control unit 49 and can communicate with external devices. For example, it transmits and receives various information to and from external devices via wireless communication. The communication module 60 may be located either inside or outside the electronic control unit 49. The external device may be, for example, the base station 10 or user terminal 20 described above. Furthermore, the communication module 60 may be, for example, at least one of the base station 10 and user terminal 20 described above (or may function as at least one of the base station 10 and user terminal 20).

The communication module 60 may transmit at least one of the following to an external device via wireless communication: signals from the various sensors 50-58 described above input to the electronic control unit 49; information obtained based on the signals; and information based on input from the outside (user) obtained via the information service unit 59. The electronic control unit 49, the various sensors 50-58, the information service unit 59, etc. may be referred to as input units that accept input. For example, the PUSCH transmitted by the communication module 60 may include information based on the above input.

The communication module 60 receives various information (traffic information, traffic signal information, vehicle distance information, etc.) transmitted from external devices and displays it on the information service unit 59 installed in the vehicle. The information service unit 59 may also be called an output unit that outputs information (for example, outputs information to a device such as a display or speaker based on the PDSCH (or data/information decoded from the PDSCH) received by the communication module 60).

The communication module 60 also stores various information received from external devices in memory 62 that can be used by the microprocessor 61. Based on the information stored in memory 62, the microprocessor 61 may control the drive unit 41, steering unit 42, accelerator pedal 43, brake pedal 44, shift lever 45, left and right front wheels 46, left and right rear wheels 47, axles 48, various sensors 50-58, and the like provided on the vehicle 40.

Furthermore, the base station in the present disclosure may be read as a user terminal. For example, each aspect/embodiment of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between multiple user terminals (which may be called, for example, Device-to-Device (D2D), Vehicle-to-Everything (V2X), etc.). In this case, the user terminal 20 may be configured to have the functions possessed by the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to communication between terminals (for example, "sidelink"). For example, terms such as uplink channel and downlink channel may be read as sidelink channel.

Similarly, the user terminal in this disclosure may be interpreted as a base station. In this case, the base station 10 may be configured to have the functions possessed by the user terminal 20 described above.

In this disclosure, operations described as being performed by a base station may in some cases also be performed by its upper node. It is clear that in a network including one or more network nodes having base stations, various operations performed for communication with terminals may be performed by the base station, one or more network nodes other than the base station (such as, but not limited to, a Mobility Management Entity (MME), a Serving-Gateway (S-GW), etc.), or a combination thereof.

Each aspect/embodiment described in this disclosure may be used alone, in combination, or switched between depending on the implementation. Furthermore, the processing procedures, sequences, flowcharts, etc. of each aspect/embodiment described in this disclosure may be rearranged unless inconsistent. For example, the methods described in this disclosure present elements of various steps in an exemplary order, and are not limited to the particular order presented.

The aspects/embodiments described in this disclosure may be implemented using standards such as Long Term Evolution (LTE), LTE-Advanced (LTE-A), LTE-Beyond (LTE-B), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 6th generation mobile communication system (6G), xth generation mobile communication system (xG (x is, for example, an integer or decimal number)), Future Radio Access (FRA), New-Radio Access Technology (RAT), New Radio (NR), New radio access (NX), Future generation radio access (FX), Global System for Mobile communications (GSM (registered trademark)), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.17 (WiMAX (registered trademark)), IEEE 802.18 (WiMAX (registered trademark)), IEEE 802.19 (WiMAX (registered trademark)), IEEE 802.20 (WiMAX (registered trademark)), IEEE 802.21 (Wi-Fi (registered trademark)), IEEE 802.22 (WiMAX (registered trademark)), IEEE 802.23 (WiMAX (registered trademark)), IEEE 802.24 (WiMAX (registered trademark)), IEEE 802.25 (WiMAX (registered trademark)), IEEE 802.26 (WiMAX (registered trademark)), IEEE 802.27 (WiMAX (registered trademark)), IEEE 802.28 (WiMAX (registered trademark)), IEEE 802.29 ... The present invention may be applied to systems that use IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), or other suitable wireless communication methods, or to next-generation systems that are expanded, modified, created, or defined based on these. Furthermore, the present invention may be applied to a combination of multiple systems (e.g., a combination of LTE or LTE-A and 5G).

As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must in some way precede the second element.

As used in this disclosure, the term "determining" may encompass a wide variety of actions. For example, "determining" may be considered to be judging, calculating, computing, processing, deriving, investigating, looking up, search, inquiry (e.g., searching in a table, database, or another data structure), ascertaining, etc.

"Determining" may also be considered to be "determining" receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), etc.

"Judgment" may also be considered to be "deciding" on resolving, selecting, choosing, establishing, comparing, etc. In other words, "judgment" may also be considered to be "deciding" on some action.

In addition, "judgment (decision)" can also be interpreted as "assuming," "expecting," "considering," etc.

As used in this disclosure, the terms "connected," "coupled," or any variation thereof, mean any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access."

For the purposes of this disclosure, when two elements are connected, they may be considered to be "connected" or "coupled" to one another using one or more wires, cables, printed electrical connections, etc., as well as using electromagnetic energy having wavelengths in the radio frequency range, microwave range, light (both visible and invisible) range, etc., as some non-limiting and non-exhaustive examples.

In this disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "combined" may also be interpreted in the same way as "different."

When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Furthermore, when the term "or" is used in this disclosure, it is not intended to be an exclusive or.

In this disclosure, where articles are added by translation, such as a, an, and the in English, this disclosure may include the noun following these articles being plural.

The invention according to the present disclosure has been described in detail above, but it will be clear to those skilled in the art that the invention according to the present disclosure is not limited to the embodiments described herein. The invention according to the present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the invention as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and explanatory and does not pose any limiting meaning to the invention according to the present disclosure.

Claims (6)

a receiving unit for receiving at least one of information regarding a time domain resource indicated by a channel state information reference signal in a time unit longer than a slot, and information regarding a frequency domain resource supporting a frequency domain density of at least less than 0.5 by the channel state information reference signal ;
A terminal having a control unit that measures the channel state information reference signal based on at least one of information regarding the time domain resource and information regarding the frequency domain resource, performs machine learning on the results of the measurement, and estimates a channel using the machine learning interpolation . The terminal of claim 1, wherein the information about the time domain resource includes information about an offset indicated in time units longer than a slot. The terminal according to claim 1 or claim 2, wherein the information regarding the frequency domain resources includes information regarding one or more resource blocks to which the channel state information reference signal is assigned among a plurality of resource blocks. The terminal according to claim 3, wherein information regarding one or more resource blocks to which the channel state information reference signal is assigned is indicated in a bitmap format. receiving at least one of information regarding time domain resources for a channel state information reference signal indicated in time units longer than a slot, and information regarding frequency domain resources for the channel state information reference signal supporting a frequency domain density at least less than 0.5;
measuring the channel state information reference signal based on at least one of information about the time domain resource and information about the frequency domain resource;
A wireless communication method for a terminal, comprising a step of machine learning the results of the measurement and estimating a channel using the completion obtained by the machine learning . A system comprising a base station and a terminal,
The base station
a transmitter for transmitting at least one of information on a time domain resource indicated by a time unit longer than a slot for a channel state information reference signal and information on a frequency domain resource supporting a frequency domain density at least smaller than 0.5 for the channel state information reference signal;
The terminal
a receiver for receiving at least one of information about the time domain resource and information about the frequency domain resource;
A control unit that measures the channel state information reference signal based on at least one of information about the time domain resource and information about the frequency domain resource, performs machine learning on the results of the measurement, and performs channel estimation using the machine learning interpolation.