JP7670185B2 - User Equipment and Base Station - Google Patents

Description

Non-limiting, exemplary embodiments of the present disclosure relate generally to the field of wireless communication technologies, and more particularly to methods and apparatus for reference signal transmission and reception in wireless communication systems.

The new radio access system, also known as the NR system or network, is the next generation of communication system. At the Radio Access Network (RAN) #71 meeting for the Third Generation Partnership Project (3GPP) Working Group, the study of the NR system was approved. The NR system considers frequencies up to 100 GHz with the aim of a single technical framework that addresses all usage scenarios, requirements, and deployment scenarios defined in Technical Report TR 38.913, including requirements such as enhanced mobile broadband, large-scale machine-type communications, and ultra-high reliability and low latency communications.

Initial work in this research item should assign a high priority to achieving a common understanding of what is required in terms of wireless protocol structure and architecture, and should focus on progress in the following areas:
Basic physical layer signal structure for new RATs OFDM based waveforms, potential support for non-orthogonal waveforms and multiple access FFS: other waveforms where they show legitimate gains Basic frame structure Channel coding schemes

In addition, it is necessary to study and identify the technical features required to enable new wireless access, such as:
Efficient multiplexing of traffic for different services and use cases over the same contiguous spectrum block

Furthermore, dynamic/flexible bandwidth allocation and configurable RS patterns (including density) were also agreed upon for RAN1.

Dynamic/flexible bandwidth allocation means that dynamic/flexible and UE-specific bandwidth allocation is supported in NR. Therefore, in such cases, the UE does not know the full system bandwidth on the network side, different UEs may require different reference signal sequences, and it is not possible to generate a shared RS sequence for the UE using existing RS sequence generation solutions. On the other hand, the RS pattern can also be configurable (e.g., configurable density in the time/or frequency domain), and therefore legacy RS sequences cannot meet the requirements for different patterns, especially with respect to multi-user scheduling.

In the present disclosure, a new solution for transmitting and receiving reference signals in a wireless communication system is provided to alleviate or at least mitigate at least some of the problems in the prior art.

According to a first aspect of the present disclosure, a reference signal transmission method in a wireless communication system is provided. The method includes: generating a common reference signal sequence shared by at least some of the terminal devices, each assigned its own reference signal transmission configuration, based on a frequency range configuration on the network side; and transmitting the common reference signal sequence and sequence configuration information to the terminal devices, the sequence configuration information indicating parameters by which an initial reference signal sequence transmitted to the terminal devices can be obtained.

According to a second aspect of the present disclosure, a method for receiving a reference signal in a wireless communication system is provided. The method includes receiving a reference signal sequence transmitted from a network side and sequence configuration information indicating parameters for acquiring an initial reference signal sequence transmitted to the terminal device, and acquiring an initial reference signal sequence for the terminal device based on the sequence configuration information.

According to a third aspect of the present disclosure, an apparatus for reference signal transmission in a wireless communication system is provided. The apparatus includes a reference signal generation module and a sequence and information transmission module. The reference signal generation module is configured to generate a common reference signal sequence shared by at least some of the terminal devices, each assigned their own reference signal transmission configuration, based on a frequency range configuration on the network side. The sequence and information transmission module is configured to transmit the common reference signal sequence and sequence configuration information to the terminal devices, the sequence configuration information indicating parameters by which an initial reference signal sequence transmitted to the terminal devices can be obtained.

According to a fourth aspect of the present disclosure, an apparatus for receiving a reference signal in a wireless communication system is provided. The apparatus includes a sequence and signal receiving module and a sequence acquisition module. The sequence and signal receiving module is configured to receive a reference signal sequence transmitted from a network side and sequence configuration information indicating parameters for acquiring an initial reference signal sequence transmitted to the terminal device. The sequence acquisition module is configured to acquire the initial reference signal sequence for the terminal device based on the sequence configuration information.

According to a fifth aspect of the present disclosure, there is provided a computer-readable storage medium having computer program code embodied therein, the computer program code being configured, when executed, to cause an apparatus to perform operations within a method according to any embodiment of the first aspect.

According to a sixth aspect of the present disclosure, there is provided a computer-readable storage medium having computer program code embodied therein, the computer program code being configured, when executed, to cause an apparatus to perform operations within a method according to any embodiment of the second aspect.

According to a seventh aspect of the present disclosure, there is provided a computer program product comprising a computer-readable storage medium according to the fifth aspect.

According to an eighth aspect of the present disclosure, there is provided a computer program product comprising a computer-readable storage medium according to the sixth aspect.

In an embodiment of the present disclosure, a low-complexity reference signal sequence solution for wireless communication systems (especially new radio access systems) with dynamic bandwidth allocation and/or configurable reference signal patterns is proposed. A common reference signal sequence is generated and shared by at least some terminal devices regardless of reference signal transmission configurations such as bandwidth allocation and/or reference signal pattern configurations. Thus, it is possible to perform RS measurements and multi-user scheduling for UEs even if they are configured with different bandwidth allocations and/or configurable reference signal patterns. Furthermore, it can achieve better interference cancellation because reference signals from interfering cells are easier to obtain. Moreover, it only requires the terminal device to generate a small number (e.g., only one) of reference signal sequences for different band allocations and/or RS pattern configurations, which means a less complex solution.

The above and other features of the present disclosure will become more apparent through a detailed description of the embodiments shown in the accompanying drawings, in which the same reference numerals represent the same or similar components throughout.

FIG. 1 shows a schematic diagram of a system bandwidth configuration in an LTE system.

FIG. 2 illustrates a schematic example of a potential problem associated with dynamic bandwidth allocation in an NR system.

FIG. 3 illustrates a schematic example of a potential problem associated with a configured RS pattern in an NR system.

FIG. 4 illustrates generally a flow chart of a method for reference signal transmission according to an exemplary embodiment of the present disclosure.

FIG. 5 illustrates generally common RS sequences and RS sequences for respective UEs having different frequency band allocations according to an exemplary embodiment of the present disclosure.

FIG. 6 illustrates a schematic diagram of an exemplary common RS sequence generation according to another embodiment of the present disclosure.

FIG. 7 illustrates a schematic diagram of an exemplary common RS sequence generation with a fixed index according to a further embodiment of the present disclosure.

FIG. 8 illustrates generally an exemplary common RS sequence generation with a fixed index according to yet a further embodiment of the present disclosure.

FIG. 9 illustrates generally an example common RS sequence for a UE with a configurable RS pattern according to a still further embodiment of the present disclosure.

FIG. 10 illustrates generally common RS sequences and RS sequences for respective UEs with different RS densities according to one embodiment of the present disclosure.

FIG. 11 illustrates generally a common RS sequence and an RS sequence for each UE having different RS configurations in the time domain according to another example embodiment of the present disclosure.

FIG. 12 illustrates generally common RS sequences and RS sequences for respective UEs having different band allocations in the frequency domain and different RS configurations in the time domain according to another example embodiment of the present disclosure.

FIG. 13 illustrates a schematic diagram of different variable modes of modulation symbols in an RS sequence according to an embodiment of the present disclosure. FIG. 14 illustrates a schematic diagram of different variable modes of modulation symbols in an RS sequence according to an embodiment of the present disclosure. FIG. 15 illustrates a schematic diagram of different variable modes of modulation symbols in an RS sequence according to an embodiment of the present disclosure.

FIG. 16A illustrates a schematic diagram of generation of a common RS sequence for symbols with different densities according to one embodiment of the present disclosure. FIG. 16B illustrates a schematic diagram of generation of common RS sequences for symbols with different densities according to one embodiment of the present disclosure.

FIG. 17 illustrates generally a flow chart of a method for reference signal reception according to one embodiment of the present disclosure.

FIG. 18 illustrates generally a block diagram of an apparatus for reference signal transmission according to one embodiment of the present disclosure.

FIG. 19 illustrates generally a block diagram of an apparatus for reference signal reception according to one embodiment of the present disclosure.

FIG. 20 further shows a simplified block diagram of an apparatus 2010 that may be embodied as or included in a serving node, such as a base station in a wireless network, and an apparatus 2020 that may be embodied as or included in a terminal device, such as described herein as a UE.

The solutions provided in the present disclosure will be described in detail below through embodiments with reference to the accompanying drawings. It should be understood that these embodiments are presented only to enable those skilled in the art to better understand and implement the present disclosure, and are not intended to limit the scope of the present disclosure in any way.

In the accompanying drawings, various embodiments of the present disclosure are illustrated in block diagrams, flow charts and other diagrams. Each block in the flow chart or block may represent a module, program or part of code that includes one or more executable instructions for performing a specific logical function, and in this disclosure, unnecessary blocks are illustrated with dotted lines. Furthermore, although these blocks are illustrated in a specific order for performing the steps of the method, in reality, they may not necessarily be performed according to the strictly illustrated order. For example, they may be performed in reverse order or simultaneously, depending on the nature of the respective operations. Each block in the block diagram and/or flow chart, as well as combinations thereof, may be implemented by a dedicated hardware-based system for performing the specific function/operation, or by a combination of dedicated hardware and computer instructions.

In general, all terms used in the claims should be interpreted according to their ordinary meaning in the art, unless expressly defined otherwise herein. All references to "a/an/the/said [element, apparatus, component, means, step, etc.]" should be openly interpreted as referring to at least one example of said element, apparatus, component, means, unit, etc., and should not be interpreted as excluding a plurality of such apparatus, components, means, units, steps, etc., unless otherwise stated. Furthermore, the indefinite article "a/an" as used herein does not exclude a plurality of such steps, units, modules, devices, objects, etc.

Furthermore, in the context of this disclosure, User Equipment (UE) may refer to a terminal, a Mobile Terminal (MT), a subscriber station, a mobile subscriber station, a Mobile Station (MS), or an Access Terminal (AT), and may include some or all of the functionality of a UE, a terminal, an MT, an SS, a mobile subscriber station, an MS, or an AT. Furthermore, in the context of this disclosure, the term "BS" may represent, for example, a Node B (Node B or NB), an evolved Node B (eNode B or eNB), a gNB (Node B in NR), a Radio Header (RH), a Remote Radio Head (RRH), a relay, or a low-power node such as a femto or pico.

In the following, to facilitate understanding of the embodiments of the present disclosure, we first describe channel state information-reference signal (CSI-RS) sequence generation in an LTE system.

は、以下によって定義される。

ここで、ｎ_ｓは無線フレーム内のスロット番号であり、

はスロット内のＯＦＤＭのシンボル番号である。c（i）は擬似乱数列生成器によって生成された擬似乱数列で、次のように初期化される。

各ＯＦＤＭシンボルの先頭に以下が付加される。

そして、ここで、量

がよりレイヤの高い層によって構成されない場合、量

は

に等しい。 According to the generation of CSI-RS in LTE, the reference signal sequence

is defined as follows:

where _ns is the slot number in the radio frame,

is the OFDM symbol number in the slot. c(i) is the pseudorandom sequence generated by the pseudorandom sequence generator and is initialized as follows:

The following is prepended to each OFDM symbol:

And here, the amount

If not composed of higher layers, the amount

teeth

is equal to.

は、以下に従ったアンテナポートｐ上の基準シンボルとして使用される複素数値変調シンボル

にマッピングされるものとする。

In a subframe configured for CSI reference signal transmission, the reference signal sequence

is the complex-valued modulation symbol used as a reference symbol on antenna port p according to

shall be mapped to

Therefore, it is clear that the CSI-RS sequence is generated with a fixed maximum length N _RB ^{max, DL} and a configured length N _RB ^DL _, ^which is related to the system bandwidth configuration in the network.

The index for CSI-RS sequence generation is known to the UE, N _RB ^max,DL is fixed to 110, N _RB ^DL is obtained from the Physical Broadcast CHannel (PBCH), and CSI-RS is full band one. Thus, the generated CSI-RS can be shared by all UEs in the cell.

Therefore, in LTE systems, the CSI-RS sequence is generated with a fixed maximum length, and as shown in Figure 1, each of the six different configurations of the system bandwidth has the same center frequency and the generated CSI-RS sequence is fixed. Therefore, for the same cell ID, the CSI-RS sequence is common to all UEs in the cell.

However, things will be different in an NR system. As mentioned above, dynamic/flexible bandwidth allocation is supported in an NR system, and therefore the UE does not know the full system bandwidth on the network side. Furthermore, different UEs may be assigned different frequency bands, and therefore different UEs may require different reference signal sequences. With existing RS sequence generation solutions, it is not possible to generate a single RS sequence that can be shared for UEs.

Figure 2 shows an example of a potential problem associated with dynamic bandwidth allocation in an NR system. As shown in Figure 2, there are three different UEs, namely UE1, UE2, and UE3, which are located in the same cell, but for scheduling/measurement, they are configured with UE-specific frequency bands, each of which is only a portion of the total system bandwidth configured on the network side. As shown in Figure 2, the frequency bands of different UEs may be separated and may overlap partially or completely. From the UE's perspective, the band allocation should be transparent, since its total bandwidth depends on its RF capabilities and it is not mandatory to know the system bandwidth on the network side.

In such cases, RS configuration with dynamic band allocation may cause some problems. For example, for cell or beam specific RS, it shall be common or shared by a group of UEs, like RS for CSI measurement. Furthermore, considering multi-user MIMO scheduling, demodulation RS should also be unified for orthogonally co-scheduling. Even for different sequences of RS for quasi-orthogonal or inter-cell/intra-cell interference management, RS sequence should be known to other UEs for advanced interference cancellation. In such cases, RS configuration with dynamic band allocation would be problematic, although it would not enable RS sharing.

Furthermore, in NR systems, UEs can be configured with UE-specific RS patterns (e.g., UE-specific RS densities) in the time/frequency domain. In such cases, it is also not possible to share common RSs with existing RS generation solutions. However, common RS generation can also be beneficial in many cases, especially when the RS pattern is dynamically changed, since the UE can extract the required RSs from a common sequence. Furthermore, a common sequence can facilitate multi-user scheduling.

しかしながら、そのような場合、図３に示されるように、異なるＲＳパターンに対して直交性は保証され得ず、これは各ＵＥに対するチャネルＨ１およびＨ２が推定できないことを意味する。さらに、各ＵＥは、他のＵＥに干渉を引き起こす可能性があり、高度なＵＥでは、他のＵＥからの干渉を差し引くことができない。したがって、レガシーＲＳシーケンス生成は、異なるＲＳパターン、特にマルチユーザスケジューリングのために、要件も満たすことができない。 As shown in FIG. 3, if the UEs generate their RS sequences separately, the signals received on the REs are _Y1 and _Y2 , which can be expressed as follows, respectively:

However, in such a case, as shown in Fig. 3, orthogonality cannot be guaranteed for different RS patterns, which means that the channels H1 and H2 for each UE cannot be estimated. Furthermore, each UE may cause interference to other UEs, and advanced UEs cannot subtract interference from other UEs. Therefore, legacy RS sequence generation cannot meet the requirements for different RS patterns, especially for multi-user scheduling.

In view of the above, in this disclosure, a common RS sequence design solution is proposed that is independent of UE bandwidth or RS pattern configuration. With common RS sequence design, a group of UEs with their own RS transmission configurations can share a common RS sequence such as their RS for measurement and multi-use scheduling. Moreover, it may achieve better interference cancellation since the RS from the interfering cells is easier to acquire. Moreover, the UE only needs to generate several sequences (e.g. only one) for different band allocation/pattern configurations, which means less complexity in RS sequence generation.

In the following, solutions for reference signal transmission and reception as proposed herein are described with reference to the accompanying drawings. However, it should be noted that these descriptions are for illustrative purposes only and that the present disclosure is not limited thereto.

Referring first to FIG. 4, it generally illustrates a flow chart of a method 400 of reference signal transmission in a wireless communication system according to an embodiment of the present disclosure. The method 400 may be performed in a serving node, such as a BS, a Node B (NodeB or NB), for example.

As shown in FIG. 4, first, in step 401, a common reference signal sequence is generated based on a frequency range configuration on the network side, and the common reference signal can be shared by at least some terminal devices each assigned their own reference signal transmission configuration.

In one embodiment of the present disclosure, the common reference signal sequence is generated on the network side based on the system bandwidth. In other words, the length of the common reference signal sequence is determined based on at least the total system bandwidth on the network side.

As shown in FIG. 5, the common reference signal sequence R_i consists of R_0, R_1, R_2, ..., R_M-2, R_M-1, where M is the length of the reference signal R_i and is at least related to the system bandwidth on the network side. In addition, it may also be further related to the minimum subcarrier spacing (SCS: SubCarrier Space).

、ｃｅｌｌ＿ＩＤ Ｎ^ＩＤ、ＵＥ＿ＩＤ Ｕ^ＩＤ、ＣＰタイプＮ_ＣＰ、ＳＣＳ構成のインデックスＮ_ＳＣＳ、リンクタイプＮ_{ｌｉｎｋ＿ｔｙｐｅ}等の少なくとも一つに関連するパラメータを用いて計算することができる。以下、本開示の例示的な実施形態では、Ｃ＿ｉｎｉｔを決定することができる。

ここで、ａ_ｉは各要素の係数であり、ｉ＝０、１、…、であり、パラメータ数Ｎ_ＳＣＳは、サブキャリア間隔構成のパラメータであり、Ｎ_ＳＣＳの値は、一組の値から選択することができ、サブキャリア間隔に対応する各値Ｎ_{ｌｉｎｋ＿ｔｙｐｅ}は、初期値がダウンリンク、アップリンク、またはサイドリンクであることを示すリンクタイプのパラメータである。端末装置の少なくともいくつかについては、それらは同じＵ^ＩＤを割り当てられ、したがって、それらは生成されたＲＳシーケンスを共有することができることに留意されたい。 The sequence R_i may be defined by a pseudo-random sequence that may be initialized by a pseudo-random sequence generator with an initial value C_init, which is the slot index n _s , the symbol index

, cell_ID N ^ID , UE_ID U ^ID , CP type N _CP , SCS configuration index N _SCS , link type N _{link_type} , etc. In the following, in the exemplary embodiment of the present disclosure, C_init can be determined.

where _ai is the coefficient of each element, i=0, 1, ..., the number of parameters N _SCS is a parameter of subcarrier spacing configuration, the value of N _SCS can be selected from a set of values, and each value N _{link_type} corresponding to the subcarrier spacing is a parameter of link type indicating that the initial value is downlink, uplink, or sidelink. It should be noted that for at least some of the terminal devices, they are assigned the same U ^ID , and therefore they can share the generated RS sequence.

In one embodiment of the present disclosure, the following table can be used to illustrate the subcarrier spacing configuration.
Table 1. Example of subcarrier spacing configuration

Regarding the link type parameter N _{link_type} , the following table can be used as a way to indicate the link type.
Table 2. Examples of link type display

For downlink or uplink, the RS sequence is symmetric and the sequences are generated with different initial values.

Thus, for a common RS sequence with length M as shown in FIG. 5, for different UEs with different bandwidth configurations, e.g., configured in different frequency ranges/locations within the system frequency band, their respective RS sequences will start at different indices of the common RS sequence and have different lengths. As shown, the RS sequence of UE1 may start at i_start_1 (R_3 of the common RS sequence) and end at i_end_1 (R_10 of the common RS sequence). The RS sequence of UE2 may start at i_start_2 (R_i of the common RS sequence) and end at i_end_2 (R_M-2 of the common RS sequence). The RS sequence of UE3 may start at i_start_3 (R_2 of the common RS sequence) and end at i_end_3 (R_i+2 of the common RS sequence). In other words, the RS sequences for each UE will correspond to their own assigned frequency band. Here, the starting index of the UE's RS sequence is also called the index of the UE's RS sequence.

Returning to FIG. 4, in step S402, a common reference signal sequence and sequence configuration information are transmitted to the terminal device, and the sequence configuration information indicates parameters by which the initial reference signal sequence transmitted to the terminal device can be obtained.

The common RS sequence can be transmitted to at least some terminal devices, each of which receives the RS sequence for itself in its own assigned band. However, the terminal devices also need to know the initial modulation symbols of the RS sequence (i.e., the initial RS sequence without the channel) to perform, for example, channel measurements or simultaneous scheduling. This allows sequence configuration information to also be transmitted to the terminal devices, indicating parameters with which the initial reference signal sequence transmitted to the terminal devices can be obtained. The parameters carried in the sequence configuration information allow the terminal devices to obtain the RS sequence from the common RS sequence generated in a manner similar to that described in step 401.

In one embodiment of the present disclosure, the sequence configuration information may be transmitted to the terminal device in an explicit manner. For example, the sequence configuration information may include sequence position information indicating a position where the reference signal sequence for the terminal device is located in the common reference signal sequence. The sequence position information may include any of the following:
1) The start and end indexes of the reference signal sequence for the terminal device, i_start_ue and i_end_ue.
2) The starting index and length of the reference signal sequence for the terminal device, i_start_ue and m_ue.
3) The end index and length of the reference signal sequence for the terminal device, i_end_ue and m_ue.

Furthermore, it can be seen that, unlike the RS generation solution in LTE, the index of the RS sequence for the terminal device does not correspond to the index of the frequency band. In such a case, it is also possible to transmit an offset value for the frequency configuration of the terminal device to the terminal device. The offset value indicates the offset of the index of the RS sequence for the terminal device with respect to the index of the frequency band assigned to the terminal device. In another embodiment of the present disclosure, it is also possible to transmit an offset value for a fixed frequency position. In this way, the terminal device also knows how to obtain its RS sequence.

In another embodiment of the present disclosure, it may also transmit the length M of the common RS sequence to the UE.

In another embodiment of the present disclosure, it is also possible to transmit sequence configuration information implicitly. In other words, the sequence configuration information can be implicitly indicated from other parameters. Examples of these parameters include, but are not limited to, the boundaries/lengths of the frequency bands assigned to the terminal device, the frequency band configuration of the terminal device, and the sequence generation initial values of the terminal device.

As mentioned before, the RS sequence for a terminal device corresponds to its own assigned bandwidth, and therefore the boundary/length of the frequency band assigned to the terminal device can be used to implicitly indicate the sequence configuration information. Furthermore, if the band of the terminal device is selected from a group of predefined bands with a predefined indication value, the frequency band configuration allows the terminal device to learn the assigned frequency band from the predefined value and thus obtain the sequence configuration information. Moreover, it is also possible to transmit to the terminal device a sequence initialization value C_init_ue from which the terminal device can generate the RS sequence from itself. C_init_ue is specific to the terminal device, but is derived from C_init for the common RS sequence, thus making the symbols of the RS sequences for different terminal devices the same at the same frequency or time position.

As mentioned above, it should be noted that although the present disclosure is described using an embodiment in which the common RS sequence is generated based on the system bandwidth on the network side, the present disclosure is not limited thereto. In one embodiment of the present disclosure, the common RS sequence can be generated based on a frequency band configured for a node serving a terminal device, rather than the entire system bandwidth. It should be understood that different serving nodes may be assigned different frequency bandwidths, and in such a case, the network may also generate a common RS sequence corresponding to the assigned frequency bandwidth.

For example, for different frequency range configurations, the starting index for RS sequence generation may be different. However, in such a case, a common reference signal sequence can be generated based on a frequency range that covers all possible frequency ranges of the different frequency range configurations. In such a case, it will ensure that the RS sequences for the different frequency range configurations have the same values at the same frequency positions.

For example, as shown in FIG. 6, there are two different frequency range configurations: frequency range 1 and frequency range 2. In other words, two transmission and reception points (TRPs)/cells, or two configurations of one cell, are configured with different frequency bands/or numerology allocations. If the UE needs to measure inter-TRP/cell interference, the RS sequences should be the same in some areas (e.g., for overlapping parts). In this case, it is possible to generate a common sequence from the same starting position idx_rs corresponding to the lower limits of the two frequency ranges.

For each UE, an index idx_rs for RS generation may be indicated to the UE, and an offset value k for idx_rs may also be indicated to the UE. In such a case, the UE may determine the start index of its RS sequence, e.g., as idx_rs1=idx_rs+k. Alternatively, a start index idx_b1 for band/numerology allocation for the UE, independent of idx_rs, may be indicated to the UE. RS sequences for two different frequency range configurations may be obtained from a common RS sequence generated from idx_rs. RS sequence parameters (e.g., for the serving cell and neighboring cell) may be indicated to the UE. The parameters may include at least one of a start index, a length, an end index, an offset value, a numerology, etc.

In one embodiment of the present disclosure, the different frequency range configurations may have at least one of different subcarrier spacing configurations and different cyclic prefix configurations.

In an embodiment of the present disclosure, a fixed index can be used for RS sequence generation for different numerologies. The index can be detected by the UE, for example, by a synchronization signal. In other words, for numerologies in different numerology configurations, a common reference signal sequence can be generated based on a frequency range that covers all possible frequency ranges of the numerology. Also, a fixed index and an offset value for the fixed index can be used to indicate sequence configuration information.

Figure 7 illustrates an exemplary common RS sequence generation using a fixed index according to one embodiment of the present disclosure. As shown, for various numerology configurations, including, for example, three numerologies, for each of numerologies 1, 2, and 3 in these numerology configurations, the common RS sequence generation can use a fixed index, i.e., index 1, 2, or 3, respectively. That is, the common RS sequence generation is generated based on a frequency range that covers all possible frequency ranges of the numerology, and a fixed index and an offset value are used as sequence configuration information. In this way, it is possible to keep the reference signal the same at the same frequency position.

Figure 8 illustrates an exemplary common RS sequence generation with fixed indexes, according to another embodiment of the present disclosure. This solution is substantially similar to the solution of Figure 7, except that the indexes are fixed to the center positions of each frequency range. That is, all frequency ranges have the same center frequency position.

In another embodiment of the present disclosure, the index for generating RS sequences for different numerologies can be configured by the network.

Hereinafter, the present disclosure is described primarily with reference to dynamic bandwidth allocation, but the present disclosure is not limited thereto. The present disclosure may also be used in configurable RS patterns, which may include at least one of a reference signal density configuration in the time domain, a reference signal density configuration in the frequency domain, and a reference signal frequency offset configuration. In such cases, it would be advantageous if a common reference signal sequence is generated further based on the full set of resource elements used for RS transmission in different reference signal configurations.

As shown in FIG. 9, the RS patterns are nested in the time-frequency domain, and when configurable RS patterns are supported in the NR system, there may be various RS patterns, with different offsets, with different densities, with/without different transmissions, etc., as shown in the right diagram in FIG. 9. In such a case, as shown in the left diagram in FIG. 9, the entire set of resource elements used for RS transmission in different RS configurations can be obtained, and therefore the REs and modulation symbols on the associated REs can all be selected from the entire set. Then, it is possible to generate a common RS sequence further based on the entire set of resource elements used for RS transmission in different reference signal configurations. Thus, the RS sequence for the RS pattern of the terminal device can be obtained from the common RS sequence.

With a common RS sequence generated based on the entire set of resource elements used for RS transmission in different reference signal pattern configurations, for UEs having different RS patterns, such as different densities, their respective RS sequences obtain a common RS sequence.

、またはＲ＿ｉ、ｉ＝１、３、５…である。 FIG. 10 illustrates a schematic of a common RS sequence and RS sequences for each UE with different RS densities according to an embodiment of the present disclosure. As shown, the common RS sequence has length M, and thus the sequence can be represented by R_i, i=0, 1, ..., M-1. For UEs configured with different densities, the density configuration can be signaled to the UE. For different density configurations, the UE can extract the required sequence from the common sequence R_i. For example, for a density 1 UE, the sequence is R_i, i=0, 1, ..., M-1, and for a density 1/2 UE, the sequence is

, or R_i, i = 1, 3, 5...

Similarly, for different SCS configurations, the UE can also extract the required sequences from the common sequences.

ここで、ｉ＿ｓｔａｒｔはシーケンスの開始インデックス、ｉ＿ｅｎｄはシーケンスの終了インデックス、Ｋは密度のパラメータ（１／２密度構成の場合、Ｋ＝２）、または、ＳＣＳのパラメータ（Ｋ・ｋ０、ここで基準ＳＣＳはｋ０である）、ｏはオフセット構成である。これらのパラメータは、個別に設定することも、一緒に設定することもできる。基準ＳＣＳ ｋ０は、ネットワークによって構成することができる。たとえば、ネットワークによっては、基準ＳＣＳは１５ｋＨｚ、３０ｋＨｚ、６０ｋＨｚ、１２０ｋＨｚ、または２４０ｋＨｚである。 For example, for a UE with maximum density or minimum SCS k0, the sequence is R_i, i=0, 1, ..., M-1. On the other hand, for a UE with density 1/K or SCS K*k0, the sequence can be expressed as:

where i_start is the start index of the sequence, i_end is the end index of the sequence, K is the density parameter (K=2 for 1/2 density configuration) or the SCS parameter (K·k0, where the reference SCS is k0), and o is the offset configuration. These parameters can be set individually or together. The reference SCS k0 can be configured by the network. For example, in some networks, the reference SCS is 15 kHz, 30 kHz, 60 kHz, 120 kHz, or 240 kHz.

In an embodiment of the present disclosure, for different symbols/slots, the RS sequence may be the same or may be generated with different initial values.

In another embodiment of the present disclosure, the RS sequence may be generated for the time-frequency domain. The reference density in one PRB in the frequency domain may be denoted by d0 (e.g., maximum density), the reference SCS may be denoted by k0 (e.g., minimum SCS), and the reference density in the time domain may be denoted by t0 (e.g., maximum density). The number of PRBs (based on SCS k0) may be denoted by N, the length in one symbol in the entire bandwidth may be denoted by L (e.g., L=N*d0), and the maximum length of the sequence may be denoted by M (e.g., M=L*t0). The common sequence is R_i, i=0, 1, ..., M-1. For a UE with a different configuration, it may extract the required sequence from the common RS sequence.

For UEs configured with different SCS ki, their RS sequences can be extracted for each ki/k0, as shown in FIG. 10. For UEs configured with different densities di in the frequency domain, their RS sequences can be extracted for each di/d0 from the common RS sequence, also as shown in FIG. 10. For UEs configured with different time densities ti, their RS sequences can be extracted from the RS sequence group, as shown in FIG. 11. For UEs configured with different patterns, their RS sequences can be extracted from the common RS sequence accordingly.

For UEs configured with different patterns in the time domain and different band allocations in the frequency domain, their respective RS sequences can be extracted from a common RS sequence corresponding to their band allocations and their RS patterns, as shown in Figure 12.

In an embodiment of the present disclosure, the RS modulation symbols in one symbol and one PRB are similar, and then the RS sequences of UEs with different densities in the frequency domain can be easily obtained.

In another embodiment of the present disclosure, the modulation symbols in the common reference signal sequence vary by either a predetermined number of subcarriers in the frequency domain or a predetermined number of symbols in the time domain.

As shown in FIG. 13, the modulation symbols in the common RS sequence may vary across a predefined number of subcarriers in the frequency domain. That is, within these subcarriers, the modulation symbols may be the same, but may be different from the modulation symbols in another predefined number of subcarriers.

Alternatively, as shown in FIG. 14, the modulated symbols in the common RS sequence may vary by a predetermined number of symbols in the time domain. That is, the modulated symbols in a predetermined number of symbols may be the same, but different from a predetermined number of other symbols.

Furthermore, the modulation symbols in the common RS sequence may also vary from one time-frequency block to another, as shown in Figure 15. That is, within the same time-frequency block, the modulation symbols will be the same, but from other time-frequency blocks, they will be different. The time-frequency blocks may have no frequency shift between them, as shown on the left side of Figure 15, or may have a predefined frequency shift, as shown on the right side of Figure 15.

In addition, the density of one RS in different symbols may be different as shown in Fig. 16A (without offset) and Fig. 16B (with offset). In such a case, there may be several options. In the first option, an RS sequence may be generated for the first symbol containing an RS, and the modulation symbols of the subsequent symbols may be generated based on the first symbol in the same frequency location. For example, the same as the first offset in the same frequency location or multiplied by a frequency offset (complex number). In the second option, one common RS sequence is generated for the time-frequency block, and the modulation symbols on different symbols are extracted from the common RS sequence. In the third option, an RS sequence is initialized for each symbol.

In the NR system, a phase tracking RS (PT-RS) is introduced, which is used to track phase noise or frequency offset and is a reference signal agreed upon at the RAN1#87 meeting. According to the agreement at the RAN1#87 meeting, the density of PT-RS in the frequency domain can be quite generous. In such a case, the sequence of PT-RS can be generated based on the previous DMRS at the same frequency location. That is, the PT-RS may be the same as or multiplied by the frequency offset (complex value) with the previous DMRS at the same frequency location. Alternatively, it is also possible to generate a sequence of PT-RS using a set sequence index, in which case the sequence setting information can be transmitted to the terminal device.

The above describes the operations related to the new RS solution on the network side. Below, we will explain the operations related to the new RS solution on the terminal device side with reference to Figure 17.

Figure 17 further illustrates a flowchart of a method for reference signal reception according to an example embodiment of the present disclosure. The method 1700 may be implemented in a terminal device, such as a UE, or other similar terminal device.

As shown in FIG. 17, the method starts in step 1701, where a terminal device such as a UE receives a reference signal sequence transmitted from the network side and sequence configuration information indicating parameters by which the reference signal sequence transmitted to the terminal device can be obtained.
In one embodiment of the present disclosure, the sequence configuration information may be explicit information that may include, for example, sequence position information indicating where a reference signal sequence for a terminal device is located within a common reference signal sequence. As an example, the sequence position information may include any of a start index and an end index of the reference signal sequence for the terminal device, a start index and a length of the reference signal sequence for the terminal device, an end index and a length of the reference signal sequence for the terminal device relative to an offset value for the frequency configuration of the terminal device, and an offset value for a fixed frequency position.

In another embodiment of the present disclosure, the sequence configuration information may be implicit information indicated by other parameters including, for example, the boundaries/lengths of the frequency bands assigned to the terminal device, the frequency band configuration of the terminal device, and any of the sequence generation initial values of the terminal device.

Then, in step 1702, an initial reference signal sequence for the terminal device can be obtained based on the sequence configuration information. In the terminal device, the terminal device can generate a common RS sequence in a manner similar to that described with reference to Figs. 4 to 16. Thus, the terminal device can extract its initial RS sequence based on the sequence configuration information received in step 1702. Thus, the terminal device can know the initial RS sequence that does not go through a channel between a serving node, such as a Node B, and a terminal device, such as a UE. In step 702, it is possible for the terminal device to perform, for example, channel estimation or joint scheduling with the initial RS sequence and the RS sequence in its assigned frequency band.
In one embodiment of the present disclosure, obtaining an initial reference signal sequence of the terminal device may include obtaining an initial reference signal sequence of the terminal device based on sequence configuration information of the terminal device and a reference signal pattern, The reference signal pattern may include at least one of a reference signal density configuration in a time domain, a reference signal density configuration in a frequency domain, and a reference signal frequency offset configuration.

Therefore, in the embodiment of the present disclosure, a low-complexity reference signal sequence solution is proposed for wireless communication systems (especially new radio access systems) with dynamic bandwidth allocation and/or configurable reference signal patterns, in which one common reference signal sequence can be generated and shared by at least some terminal devices regardless of the reference signal transmission configuration, such as the bandwidth allocation and/or reference signal pattern configuration. Thus, it is possible to perform RS measurements and multi-user scheduling for UEs even if they are configured with different bandwidth allocations and/or configurable reference signal patterns. Furthermore, it can achieve better interference cancellation because the reference signal from the interfering cell is easier to obtain. Furthermore, it only requires the terminal device to generate a small number (e.g., only one) of common reference signal sequences for different band allocations and/or RS pattern configurations, which means a lower complexity solution.

Furthermore, the present disclosure also provides devices for transmitting and receiving reference signals in a serving node and a terminal device in a wireless communication system, which are described below with reference to Figures 18 and 19.

FIG. 18 illustrates a block diagram of an apparatus 1800 for reference signal transmission in a wireless communication system according to an embodiment of the present disclosure. The apparatus 1800 may be implemented in a serving node, e.g., a BS, such as a Node B (NodeB or NB).

As shown in FIG. 18, the device 1800 may include a reference signal generating module 1801 and a sequence and information transmitting module 1802. The reference signal generating module 1801 may be configured to generate a common reference signal sequence shared by at least some terminal devices each assigned their own reference signal transmission configuration based on a frequency range configuration on the network side. The sequence and information transmitting module 1802 is configured to transmit the common reference signal sequence and sequence configuration information to the terminal device, where the sequence configuration information indicates parameters for obtaining the initial reference signal sequence transmitted to the terminal device.

In one embodiment of the present disclosure, the sequence configuration information may include sequence position information indicating where the reference signal sequence for the terminal device is located in the common reference signal sequence.

In another embodiment of the present disclosure, the sequence position information may include any of a start index and an end index of the reference signal sequence for the terminal device, a start index and a length of the reference signal sequence for the terminal device, an end index and a length of the reference signal sequence for the terminal device, and an offset value for the frequency configuration of the terminal device and an offset value for the fixed frequency position.

In further embodiments of the present disclosure, the sequence configuration information may be indicated by any of the boundaries/lengths of the frequency bands assigned to the terminal device, the frequency band configuration of the terminal device, and the sequence generation initial values of the terminal device.

In still further embodiments of the present disclosure, the network side frequency range configuration may include either the system bandwidth or a frequency band configured for a node that provides service to a terminal device.

In yet further embodiments of the present disclosure, the reference signal transmission configuration comprises at least one of a band allocation, a reference signal density configuration in the time domain, a reference signal density configuration in the frequency domain, and a reference signal frequency offset configuration.

In another embodiment of the present disclosure, the reference signal generation module 1801 may be further configured to generate a common reference signal sequence for different frequency range configurations based on a frequency range covering all possible frequency ranges of the different frequency range configurations. The different frequency range configurations may have at least one of different subcarrier spacing configurations and different cyclic prefix configurations.

In further embodiments of the present disclosure, the reference signal generation module 1801 may be further configured to generate a common reference signal sequence further based on the full set of resource elements used for RS transmission in different reference signal configurations.

In yet further embodiments of the present disclosure, the modulation symbols in the common reference signal sequence may vary by either a time-frequency block, a predetermined number of subcarriers in the frequency domain, and a predetermined number of symbols in the time domain.

In yet further embodiments of the present disclosure, a modulation symbol in a reference signal sequence in a symbol may be generated based on a modulation symbol in a reference signal sequence in a previous symbol in the same frequency location.

In another embodiment of the present disclosure, the reference signal sequence in a symbol may have at least one of a different density and a different frequency offset than the reference signal sequence in the previous symbol.

FIG. 19 further illustrates a block diagram of an apparatus 1900 for receiving a reference signal in a wireless communication system according to one embodiment of the present disclosure. The apparatus 1900 may be implemented in a terminal device, such as a UE, or other similar terminal device.

As shown in FIG. 19, the device 1900 may include a sequence and signal receiving module 1901 and a sequence acquisition module 1902. The signal receiving module 1901 may be configured to receive a reference signal sequence transmitted from the network side and sequence configuration information indicating parameters by which the reference signal sequence transmitted to the terminal device can be acquired. The sequence acquisition module 1902 may be configured to acquire an initial reference signal sequence for the terminal device based on the sequence configuration information.

In one embodiment of the present disclosure, the sequence acquisition module 1902 may be further configured to acquire an initial reference signal sequence for the terminal device based on sequence configuration information and a reference signal pattern for the terminal device.

The devices 1800 and 1900 have been described above with reference to Figs. 18 and 19. It should be noted that the devices 1800 and 1900 may be configured to perform the functions as described with reference to Figs. 4 to 17. Therefore, for details regarding the operation of the modules in these devices, reference may be made to the descriptions given with reference to Figs. 4 to 17 for the respective steps of the method.

It is further noted that the components of devices 1800 and 1900 may be embodied in hardware, software, firmware, and/or any combination thereof. For example, the components of devices 1800 and 1900 may each be implemented by a circuit, a processor, or any other suitable selection device.

Those skilled in the art will appreciate that the above examples are for illustrative purposes only and are not limiting, and the present disclosure is not limited thereto. Numerous variations, additions, deletions, and modifications can be readily conceived from the teachings provided herein, and all such variations, additions, deletions, and modifications are within the scope of protection of the present disclosure.

Further, in some embodiments of the present disclosure, each of the devices 1800 and 1900 may include at least one processor. At least one processor suitable for use with embodiments of the present disclosure may include, by way of example, both general-purpose and special-purpose processors, already known or developed in the future. Each of the devices 1800 and 1900 may further include at least one memory. The at least one memory may include, for example, semiconductor memory devices, such as RAM, ROM, EPROM, EEPROM, and flash memory devices. The at least one memory may be used to store a program of computer-executable instructions. The program may be written in any high-level and/or low-level compatible or interpretable programming language. According to an embodiment, the computer-executable instructions may be configured to cause the devices 1800 and 1900, using the at least one processor, to perform operations according to the methods described with reference to each of Figures 4 to 17.

FIG. 20 further illustrates a simplified block diagram of an apparatus 2010 that may be embodied as or included in a serving node, such as a base station in a wireless network, and an apparatus 2020 that may be embodied as or included in a terminal device, such as a UE, as described herein.

The device 2010 comprises at least one processor 2011, such as a data processor (DP), and at least one memory (MEM) 2012 coupled to the processor 2011. The device 2010 further comprises a transmitter TX and a receiver RX 2013 coupled to the processor 2011, which are operable to communicatively connect to the device 2020. The MEM 2012 stores a program (PROG) 2014. The PROG 2014 may include instructions that, when executed on the associated processor 2011, enable the device 2010 to operate according to embodiments of the present disclosure, such as the method 400. The combination of the at least one processor 2011 and the at least one MEM 2012 may form a processing means 2015 adapted to implement various embodiments of the present disclosure.

The device 2020 comprises at least one processor 2021, such as a DP, and at least one MEM 2022 coupled to the processor 2021. The device 2020 may further include a suitable TX/RX 2023 coupled to the processor 2021, which may be operable for wireless communication with the device 2010. The MEM 2022 stores a PROG 2024. The PROG 2024 may include instructions that, when executed on an associated processor 2021, enable the device 2020 to operate according to an embodiment of the present disclosure, e.g., to perform the method 1700. The combination of the at least one processor 2021 and the at least one MEM 2022 may form a processing means 2025 adapted to implement various embodiments of the present disclosure.

Various embodiments of the present disclosure may be implemented by computer programs, software, firmware, hardware, or combinations thereof executable by one or more of the processors 2011, 2021.

MEMs 2012 and 2022 may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory, as non-limiting examples.

Processors 2011 and 2021 may be of any type suitable for the local technical environment and may include, as non-limiting examples, one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors DSPs and processors based on multi-core processor architectures.

Furthermore, the present disclosure may also provide a carrier comprising a computer program as described above, the carrier being one of an electronic signal, an optical signal, a radio signal, or a computer-readable storage medium. The computer-readable storage medium may be, for example, an optical compact disc, or an electronic memory device such as a Random Access Memory (RAM), a Read Only Memory (ROM), a Flash memory, a magnetic tape, a CD-ROM, a DVD, a Blu-ray disc, or the like.

The techniques described herein may be implemented by various means, such that an apparatus performing one or more functions of a corresponding apparatus described in an embodiment is not limited to prior art means, but may also include separate means for performing one or more functions of a corresponding apparatus described in an embodiment, or means that may be configured to perform two or more functions. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or a combination thereof. In the case of firmware or software, it may be implemented via modules (e.g., procedures, functions, etc.) that perform the functions described herein.

The exemplary embodiments herein have been described above with reference to block diagrams and flowchart diagrams of methods and apparatus. It will be understood that each block of the block diagrams and flowchart diagrams, and combinations of blocks in the block diagrams and flowchart diagrams, can each be implemented by various means, including computer program instructions. These computer program instructions can be loaded into a general purpose computer, special purpose computer, or other programmable data processing device, in the flowchart blocks, to produce a machine, such that the instructions, executed on the computer or other programmable data processing device, create means for performing the specified functions.

Although the specification contains many specific implementation details, these should not be construed as limitations on the scope of any implementation or what may be claimed, but rather as descriptions of features that may be specific to a particular embodiment of a particular implementation. Certain features described in the context of separate embodiments herein may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, although features are described above as acting in a particular combination and may initially be claimed as such, one or more features from a claimed combination may be cut out of the combination. And, a claimed combination may be directed to a subcombination or a variation of the subcombination.

It will be obvious to those skilled in the art that as technology advances, the concept of the present invention can be implemented in various ways. The above-mentioned embodiments are given to illustrate rather than limit the present disclosure, and as those skilled in the art will readily understand, modifications and variations can be resorted to without departing from the spirit and scope of the present disclosure. Such modifications and variations are deemed to be within the scope of the present disclosure and the appended claims. The scope of protection of the present disclosure is defined by the appended claims.

Claims (10)

means for generating a first sequence for a Channel State Information Reference Signal (CSI-RS);
the first sequence is mapped within resources for the CSI-RS;
The resource is set within a user equipment (UE) specific bandwidth,
The UE-specific bandwidth is a portion of a cell-specific bandwidth in a cell,
the first sequence is defined by a first set of indexes;
the first sequence corresponds to a second set of indices indicating positions in the resource;
the values of the indices in the first set of indices correspond to the values of the indices in the second set of indices via respective offset values;
each of the index values in the second set of indexes is defined relative to a cell-specific position in the frequency domain;
The cell-specific location is common to each UE in the cell;
means configured to receive the CSI-RS from a base station at the location in the resource;
U.E. The method further comprises: receiving, from the base station, configuration information regarding the UE-specific bandwidth;
The setting information is information corresponding to a start position and a width of the UE-specific bandwidth in the frequency domain.
The UE of claim 1. The UE-specific bandwidth may overlap in the frequency domain with a UE-specific bandwidth configured for another UE.
3. The UE according to claim 1 or 2. The UE may be scheduled within its own bandwidth.
A UE as claimed in any one of claims 1 to 3. A plurality of UEs are located within the cell, and each of the plurality of UEs within the cell has a different UE-specific bandwidth.
A UE as claimed in any one of claims 1 to 4. means for generating a first sequence for a Channel State Information Reference Signal (CSI-RS);
the first sequence is mapped within resources for the CSI-RS;
The resource is set within a user equipment (UE) specific bandwidth,
The UE-specific bandwidth is a portion of a cell-specific bandwidth in a cell,
the first sequence is defined by a first set of indexes;
the first sequence corresponds to a second set of indexes indicating positions in the resource;
the values of the indices in the first set of indices correspond to the values of the indices in the second set of indices via respective offset values;
each of the index values in the second set of indexes is defined relative to a cell-specific position in the frequency domain;
The cell-specific location is common to each UE in the cell;
means configured to transmit the CSI-RS to a UE at the location in the resource.
Base station. The method further comprises: means for transmitting, to the UE, configuration information regarding the UE-specific bandwidth;
The setting information is information corresponding to a start position and a width of the UE-specific bandwidth in the frequency domain.
The base station according to claim 6. The UE-specific bandwidth may overlap in the frequency domain with a UE-specific bandwidth configured for another UE.
A base station as claimed in claim 6 or 7. The UE may be scheduled within its own bandwidth.
A base station according to any one of claims 6 to 8. A plurality of UEs are located within the cell, and each of the plurality of UEs within the cell has a different UE-specific bandwidth.
A base station according to any one of claims 6 to 9.

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