JP7757260B2 - Wireless communication device, control method thereof, and program - Google Patents

Description

The present invention relates to increasing the speed of initial access operations in wireless communications.

Currently, the Third Generation Partnership Project (3GPP (registered trademark)) is continuing development of 5G, and studies have begun on Beyond 5G and 6G (B5G/6G), which are more advanced versions of 5G. To achieve faster communications speeds with B5G/6G, the use of the terahertz band, which is higher than the frequency band currently used for wireless communications, is also being considered. As an example, a "virtualized terminal" has been proposed, which connects a user terminal and peripheral devices (such as wearable devices) in the terahertz band (Non-Patent Document 1).

KDDI, "B5G/6G White Paper 2.0.1 Edition," October 2021, pp. 43-45

However, the terahertz band has the property that radio waves tend to travel in a very straight line and have large propagation losses, so it is expected that high-gain, narrow-beam multi-beam antennas will be used for both transmission and reception. Establishing communication using a multi-beam antenna requires control to ensure that both transmission and reception are optimally tuned. For this reason, if existing wireless communication procedures (such as random access procedures) that assume an omnidirectional antenna are used for initial access when using a multi-beam antenna, it will take a long time to establish communication.

The present invention was made in consideration of these problems, and aims to provide technology that speeds up initial access operations in wireless communications.

In order to solve the above-mentioned problems, a wireless communication device according to the present invention has the following arrangement:
a first communication means for performing wireless communication based on a first communication standard using radio waves in the terahertz band, by utilizing a multi-beam antenna configured to selectively use one narrow beam from a plurality of narrow beams each having a different directivity;
a second communication means for performing wireless communication based on a second communication standard different from the first communication standard;
a transmitting means for transmitting, via the second communication means, to a counterpart device that is communicatively connected via the second communication means, setting information to be used in the counterpart device during a period in which the first communication means is executing an initial access operation;
a receiving means for receiving counterpart device side information obtained in the counterpart device regarding the initial access operation during a period in which the first communication means executes the initial access operation;
a determination means for determining a narrow beam on the local device side to be used by the first communication means in its local device multi-beam antenna and a narrow beam on the remote device side to be used by the remote device multi-beam antenna, based on the remote device side information and the local device side information obtained by the local device regarding the initial access operation during the period in which the initial access operation is performed;
and
The device itself and the other device are time-synchronized,
the host device side information includes one or more records associating a narrow beam used in transmission by the host device's multi-beam antenna with time information when the initial access operation is performed,
The counterpart device side information includes one or more records that associate the narrow beam used for reception in the counterpart device multi-beam antenna when the initial access operation is performed, time information, and reception power information .

The present invention provides technology that speeds up initial access operations in wireless communications.

1 is a schematic diagram of a wireless communication system including a UE and a PD. A diagram showing the hardware configuration of a UE and a PD. A diagram showing the functional configuration of a UE. FIG. 2 is a diagram illustrating the functional configuration of a PD. FIG. 10 is a diagram showing an operation sequence when starting terahertz communication. FIG. 10 is a diagram showing data generated when terahertz communication is started. FIG. 1 illustrates initial access via a random access procedure.

The following describes the embodiments in detail with reference to the attached drawings. Note that the following embodiments do not limit the scope of the claimed invention. While the embodiments describe multiple features, not all of these features are necessarily essential to the invention, and multiple features may be combined in any desired manner. Furthermore, in the attached drawings, the same reference numbers are used to designate identical or similar components, and redundant explanations will be omitted.

(First embodiment)
As a first embodiment of a wireless communication device according to the present invention, a wireless communication device capable of communication based on two different communication standards will be described below as an example.

<Overall system configuration>
1 is a schematic diagram of a wireless communication system 100 including a user equipment (UE) 101 and a peripheral device (PD) 102. Here, it is assumed that the UE 101 is a smartphone and the PD 102 is a smart watch, which is a wearable terminal, but the present invention is not limited to these devices. As will be described in detail later, the UE 101 and the PD 102 are configured to be capable of Bluetooth (registered trademark) (hereinafter referred to as BT) communication and terahertz communication.

In terahertz communications, both UE101 and PD102 use multi-beam antennas with high gain and narrow beams (e.g., beam widths of less than 10°) for both transmission and reception. For example, antennas for terahertz communications are configured to be able to switch directivity in multiple predetermined directions; Figure 1 shows an example of a 32-directional narrow beam for UE101 and a 12-directional narrow beam for PD102. For simplicity's sake, it is assumed here that each device can use narrow beams with similar characteristics for transmission and reception.

When terahertz communication is performed between UE101 and PD102, each device selects a narrow beam in one direction and communicates. In other words, to start data transmission and reception via terahertz communication, a beam pair (a pair of narrow beams used by UE101 and PD102) must be determined in the initial access operation.

On the other hand, BT communication uses an omnidirectional antenna. Therefore, neither UE101 nor PD102 requires beam control for communication.

<Hardware configuration>
2 is a diagram showing the hardware configuration of the UE 101. Note that the hardware configuration related to communication is also common to the PD 102, so the following description will be limited to the UE 101.

In one example, UE101 includes a processor 201, ROM 202, RAM 203, storage device 204, first communication circuit 205, and second communication circuit 206. Processor 201 is a computer including one or more processing circuits, such as a general-purpose CPU (Central Processing Unit) or ASIC (Application Specific Integrated Circuit), and performs the overall processing of the device and each of the processes described below by reading and executing programs stored in ROM 202 and storage device 204.

ROM 202 is a read-only memory that stores information such as programs related to processes executed by UE 101 and various parameters. RAM 203 functions as a workspace when processor 201 executes programs, and is random access memory that stores temporary information. Storage device 204 is configured, for example, by a removable external storage device.

The first communication circuit 205 is composed of a circuit for wireless communication that complies with a first communication standard that requires beam control to establish communication. Therefore, the first communication circuit 205 includes a circuit for beam control of a multi-beam antenna (not shown). In the following explanation, the terahertz communication standard currently under consideration will be used as an example of the first communication standard, but any communication standard that requires beam control for initial access operations can be applied.

The second communication circuit 206 is composed of a wireless communication circuit that complies with any second communication standard. However, it is desirable that the communication standard be one that allows constant communication to be established or that allows communication to be established in a short initial access operation time (for example, no beam control is required for the initial access operation). In the following explanation, BT is used as an example of the second communication standard, but it is also possible to use, for example, a wireless LAN (IEEE 802.11 series) standard or a wireless WAN (4G, 5G, etc.).

<Functional configuration of UE 101>
3 is a diagram showing the functional configuration of UE 101. UE 101 has, as its functions, for example, a first communication control unit 301, a second communication control unit 302, a control unit 303, a storage unit 304, and a display unit 305. Note that FIG. 3 only shows functions particularly related to this embodiment, and various other functions that UE 101 may have are not shown. For example, if UE 101 is a smartphone, it naturally has other functions such as various input functions (GPS receiver, camera, microphone) and various output functions (vibration, speaker, etc.).

Furthermore, the functional blocks in Figure 3 are shown schematically, and the respective functional blocks may be realized as an integrated unit, or may be further subdivided. Furthermore, each function in Figure 3 may be realized, for example, by the processor 201 executing a program stored in the ROM 202 or the storage device 204. Furthermore, each function may be realized, for example, by the processors present inside the first communication circuit 205 and the second communication circuit 206 executing predetermined software.

The first communication control unit 301 controls wireless communication via the first communication circuit 205. Specifically, it performs wireless communication compliant with the first communication standard in accordance with instructions from the control unit 303. In particular, if communication has not been established with the other device (here, PD102), it performs an initial access operation and determines the beam ID to use for communication with the other device. The beam ID is an index corresponding to the beam direction. For example, beam IDs #1 to #32 are set for the 32-directional narrow beams of UE101 as shown in Figure 1. After the beam ID to use for communication with the other device is determined, data transmission and reception with the other device is performed.

The second communication control unit 302 controls wireless communication via the second communication circuit 206. Specifically, it executes wireless communication compliant with the second communication standard in accordance with instructions from the control unit 303. As described above, an omnidirectional antenna is used in wireless communication via the second communication circuit 206, so beam control for communication is not required. Furthermore, in BT communication, if pairing (registering the other device) has been performed in advance, data can be sent and received immediately if the other device (here, PD102) is within the communication range.

The control unit 303 controls the operation of the first communication control unit 301 and the second communication control unit 302. Specifically, upon receiving an instruction from a user to start terahertz communication with a partner device via a graphical user interface (GUI) displayed on the display unit 302, the control unit 303 transmits configuration information to the partner device via the second communication control unit 302 and instructs the first communication control unit 301 to start an initial access operation. The configuration information is information used by the partner device when performing the initial access operation for terahertz communication. Then, based on the information obtained by the initial access operation (results obtained from both UE 101 and PD 102), the control unit 303 determines a beam pair (a pair of a beam ID used by UE 101 and a beam ID used by the partner device), and starts data transmission and reception via terahertz communication using the determined beam pair. Details will be described later with reference to Figures 5 and 6.

The memory unit 304 stores various information used by the control unit 303 to control the operation of the first communication control unit 301 and the second communication control unit 302. Details will be described later with reference to Figures 5 and 6. The display unit 305 accepts user input from the user and displays a GUI that provides the user with various information. For example, if the UE 101 is a smartphone, it displays a GUI for a specific application that uses terahertz communication, a communication setting application, etc.

<Functional configuration of PD 102>
FIG. 4 is a diagram showing the functional configuration of the PD 102. The PD 102 has, as its functions, for example, a first communication control unit 401, a second communication control unit 402, a control unit 403, and a storage unit 404. Note that FIG. 4 only shows functions particularly related to this embodiment, and various other functions that the PD 102 may have are not shown. For example, if the PD 102 is a smartwatch, it naturally has other functions such as various input functions (GPS receiver, biometric sensor) and various output functions (vibration, speaker, etc.). Note that, unlike the UE 101 (FIG. 3), a display unit is not shown in FIG. 4; however, this only implicitly indicates that a display unit is not essential for communication-related functions. In other words, a display unit as a peripheral device (smartwatch) may naturally be included.

Furthermore, the functional blocks in Figure 4 are shown schematically, and the respective functional blocks may be realized as an integrated unit, or may be further subdivided. Furthermore, each function in Figure 4 may be realized, for example, by the processor 201 executing a program stored in the ROM 202 or the storage device 204. Furthermore, each function may be realized, for example, by the processors present inside the first communication circuit 205 and the second communication circuit 206 executing predetermined software.

The first communication control unit 401 controls wireless communication via the first communication circuit 205. Specifically, it executes wireless communication compliant with the first communication standard in accordance with instructions from the control unit 403. In particular, it executes an initial access operation in accordance with the setting information received from UE101 via the second communication circuit 206, and stores the result in the memory unit 404. It also executes data transmission and reception via terahertz communication with the other device (UE101 in this case) in accordance with the beam ID received from UE101 via the second communication circuit 206. The beam ID is an index corresponding to the beam direction. For example, beam IDs #1 to #12 are set for the 12-directional narrow beams of PD102 as shown in Figure 1.

The second communication control unit 402 controls wireless communication via the second communication circuit 206. Specifically, it executes wireless communication compliant with the second communication standard in accordance with instructions from the control unit 403. As described above, an omnidirectional antenna is used in wireless communication via the second communication circuit 206, so beam control is not required for communication. Furthermore, in BT communication, if pairing (registering the other device) has been performed in advance, data can be sent and received immediately if the other device (in this case, UE101) is within the communication range.

The control unit 403 controls the operation of the first communication control unit 401 and the second communication control unit 402. Specifically, the control unit 403 causes the first communication control unit 401 to perform an initial access operation in accordance with the setting information received from UE 101 via the second communication circuit 206, and causes the first communication control unit 401 to store the result in the memory unit 404. The control unit 403 then transmits the result stored in the memory unit 404 to UE 101 via the second communication circuit 206. The control unit 403 also causes the first communication control unit 401 to start transmitting and receiving data via terahertz communication with the partner device in accordance with the beam ID received from UE 101 via the second communication circuit 206. Details will be described later with reference to Figures 5 and 6.

The memory unit 404 stores various information used by the control unit 403 to control the operation of the first communication control unit 401 and the second communication control unit 402. Details will be described later with reference to Figures 5 and 6.

<Device Operation>
First, we will explain the case where a random access procedure used in existing wireless communications assuming an omnidirectional antenna is applied to the initial access operation of communications using a multi-beam antenna. Figure 7 is a diagram showing the operation when the random access procedure is used for initial access. As shown in the figure, for example, the initial access operation is initiated by inputting a user instruction to both UE 701 and PD 702. However, since neither UE 701 nor PD 702 has information about the other device, each device performs beam sweeping (sequential switching of beam direction) at random timing as an autonomous operation. Then, both devices perform beam sweeping transmission operations and beam sweeping reception operations.

As a result, beam sweeping is repeatedly attempted until a pair (beam pair) of the transmit (or receive) beam direction used by UE701 and the receive (or transmit) beam direction used by PD702 coincides with an appropriate combination. In particular, the greater the number of beam directions in a multi-beam antenna, the lower the probability of an appropriate combination occurring by chance, and the longer the initial access operation takes (for example, several minutes). Furthermore, if the initial access operation takes longer, the relative positional relationship between UE701 and PD702 may change during that time (for example, due to a change in the user's position or posture), and it will take even longer for the beam pair to become an appropriate combination.

Next, an example of the flow of processing executed in the wireless communication system of the present invention will be described. Figure 5 is a diagram showing the operational sequence when UE 101 and PD 102 start terahertz communication. Figure 6 is a diagram showing the data generated when terahertz communication starts. Steps S502 to S508 correspond to the initial access operation, and steps S510 and onwards correspond to actual communication via terahertz communication. As will be described in more detail later, steps S502 to S507 are executed repeatedly, and therefore this part will be referred to as the initial access loop below.

For simplicity's sake, the following description will be based on an example in which UE101, which is capable of user input (GUI operation) that triggers the start of terahertz communication, initiates processing. However, as mentioned above, there is essentially no difference between UE101 and PD102 in terms of communication functionality, and processing can be initiated by either device.

In step S501, BT pairing is performed between UE101 and PD102. As described above, once pairing is performed, data can be sent and received immediately via BT communication if the other device is within the communication range. In addition, control is performed to synchronize the time between UE101 and PD102. In addition, UE101 and PD102 should each acquire terahertz communication capability information for the other device. In this embodiment, information regarding the beam ID range of the other device is acquired. Additional information such as the frequency width available to each device may also be acquired.

In step S502, UE 101 determines the beam ID (BeamID@PD) that PD 102 will use in the (current) initial access loop. As mentioned above, in the example of Figure 1, the range of beam IDs for PD 102 is #1 to #12, and one beam ID is selected from this range.

As described above, the initial access loop is executed repeatedly, but the beam IDs used by PD102 are determined to be different for each beam. Here, we will explain an example in which the 12 directional beams shown in Figure 1 are selected and determined in order from top to bottom, but the beam IDs used by PD102 may also be determined using other determination methods.

In step S503, UE101 notifies PD102 of the beam ID determined in S502 via BT communication. In step S504, PD102 sets the beam ID notified via BT communication in the first communication control unit 401.

In step S505, UE101 controls the first communication control unit 301 to perform beam sweeping. In step S506, PD102 controls the first communication control unit 401 to record the reception status of the beam sweeping performed by UE102.

Specifically, UE101 transmits signals while sequentially changing the beam ID (BeamID@UE) it uses (#1 to #32). It also records time information (timestamp) when it changes to each beam ID. Recording table 601 in FIG. 6 is a table (local device information) containing N records generated in storage unit 304 at this time. Meanwhile, PD102 keeps the beam ID set in S504 fixed and records the received power (RSSI, etc.) of the signal transmitted from UE101 along with time information (timestamp). Recording table 602 in FIG. 6 is a table (counter device information) generated in storage unit 404 at this time. Note that PD102 may not be able to receive signals from all beam IDs (BeamID@UE) of UE101, so recording table 602 is a table containing M or fewer records.

In step S507, PD102 transmits the record table 602 created in the memory unit 404 to UE101 via BT communication.

In the above-mentioned initial access loop (S502 to S507), PD102 sequentially changes the beam ID used for reception and sequentially transmits the recording results (recording table 602) to UE101. As a result, UE101 obtains recording table 602 and recording table 602 for the beam IDs of all 12 directions of PD102.

In step S508, UE101 generates table 603 from the obtained set of 24 (= 12 x 2) recording tables. Table 603 is a table that combines 24 recording tables based on time information (timestamp). Therefore, table 603 includes all combinations of UE101's beam ID (BeamID@UE) and PD102's beam ID (BeamID@PD) (excluding combinations that are not received at all). Therefore, by referring to table 603, UE101 determines the beam pair (the pair of UE101's beam ID and PD102's beam ID) with the best reception condition (for example, the highest reception power).

In step S509, UE101 notifies PD102 via BT communication of the beam ID (BeamID@PD; beam setting on the other device side) determined in S508. In step S510, UE101 sets the beam ID (BeamID@UE; beam setting on the own device side) determined in S508 in the first communication control unit 301. Also, in step S511, PD102 sets the beam ID notified via BT communication in the first communication control unit 401. Thereafter, in step S512, data transmission and reception via terahertz communication is started between UE101 and PD102.

By going through this procedure, it is possible to determine the beam pair with the best reception conditions. In particular, while UE101 is performing beam sweeping, PD102 waits for signals in one fixed beam direction and records the reception state. This allows UE101 to perform beam sweeping at very high speeds (e.g., several milliseconds/beam ID) depending on the accuracy of time synchronization. Therefore, even if the initial access loop is repeated as many times as the number of beam IDs in PD102, it is possible to significantly reduce the time for the initial access operation compared to when a random access procedure is used (e.g., on the order of several seconds to several tens of seconds). Note that the beam sweep speed may be determined by calculating backwards from the allowable time for the initial access operation.

In the above explanation, the sequence in Figure 5 is executed when a user input (GUI operation) that triggers the start of terahertz communication is made, but it may also be executed at other times. For example, the sequence in Figure 5 may be executed in advance, triggered by an arbitrary operation on UE101 by the user. Furthermore, if a communication interruption occurs in terahertz communication while data is being sent or received via terahertz communication (for example, due to a change in the user's position or posture), the sequence in Figure 5 may be executed again.

As described above, according to the first embodiment, the initial access operation by the first communication unit (terahertz communication) that uses a multi-beam antenna in which each beam is a narrow beam is controlled via communication by a second communication unit that is different from the first communication unit. This makes it possible to shorten the time required for the initial access operation by the first communication unit.

(Modification)
In the first embodiment described above, the reception status is detected for all combinations of beam directions (beam IDs) of UE 101 and PD 102. However, the reception status may be detected by thinning out the beam directions (beam IDs) for at least one of UE 101 and PD 102. For example, UE 101 may perform beam sweeping at intervals of five beam IDs (#1 → #6 → #11, etc.). In this case, the time required for each beam sweep (S505) can be reduced to approximately one-fifth.

Also, PD 102 may receive beam sweeps using, for example, three predetermined beam IDs. For example, in S501, PD 102 reports to UE 101 that it has three beam IDs. In this case, the number of repetitions of the initial access loop (S502 to S507) executed by UE 101 is reduced to three, further shortening the time required for the entire initial access operation.

Furthermore, in the first embodiment described above, the initial access loop (S502 to S507) is repeated the number of times corresponding to the beam IDs of PD102, and then a beam pair is determined (S508). However, a configuration in which a beam pair is determined each time an initial access loop is completed may also be used. In that case, for example, the initial access loop may be terminated when a beam pair having an RSSI value equal to or greater than a predetermined threshold is detected, and operation may proceed to S509 and subsequent steps.

Furthermore, in the above-described first embodiment, a configuration has been described in which UE101 transmits beam sweeps and PD102 receives the beam sweeps in the initial access loop. However, the opposite configuration may also be adopted in which UE101 receives beam sweeps and PD102 transmits beam sweeps in the initial access loop. In this case, in S501, UE101 determines and uses the beam ID (BeamID@UE) to be used by itself. Then, a table equivalent to record table 602 is generated in UE101, and a table equivalent to record table 601 is generated in PD102. Therefore, a configuration may be adopted in which PD102 determines the beam pair (S508), or information generated by PD102 (equivalent to record table 601) is transmitted to UE101, and UE101 determines the beam pair (S508).

The present invention also enables faster initial access operations in wireless communications. This will contribute to achieving Goal 9 of the United Nations' Sustainable Development Goals (SDGs), which states, "Build resilient infrastructure, promote sustainable industrialization and foster innovation."

The invention is not limited to the above-described embodiments, and various modifications and variations are possible within the scope of the invention.

101 User Equipment (UE); 102 Peripheral Device (PD); 301 First Communication Control Unit; 302 Second Communication Control Unit; 303 Control Unit; 304 Storage Unit; 305 Display Unit

Claims (9)

a first communication means for performing wireless communication based on a first communication standard using radio waves in the terahertz band, by utilizing a multi-beam antenna configured to selectively use one narrow beam from a plurality of narrow beams each having a different directivity;
a second communication means for performing wireless communication based on a second communication standard different from the first communication standard;
a transmitting means for transmitting, via the second communication means, to a counterpart device that is communicatively connected via the second communication means, setting information to be used in the counterpart device during a period in which the first communication means is executing an initial access operation;
a receiving means for receiving counterpart device side information obtained in the counterpart device regarding the initial access operation during a period in which the first communication means executes the initial access operation;
a determination means for determining a narrow beam on the local device side to be used by the first communication means in its local device multi-beam antenna and a narrow beam on the remote device side to be used by the remote device multi-beam antenna, based on the remote device side information and the local device side information obtained by the local device regarding the initial access operation during the period in which the initial access operation is performed;
and
The device itself and the other device are time-synchronized,
the host device side information includes one or more records associating a narrow beam used in transmission by the host device's multi-beam antenna with time information when the initial access operation is performed,
The counterpart device side information includes one or more records associating a narrow beam used for reception in the counterpart device multi-beam antenna when the initial access operation is executed, time information, and reception power information.
A wireless communication device comprising: The wireless communication device described in claim 1, characterized in that the determination means combines the records contained in the local device side information and the records contained in the remote device side information based on the time information, and determines the local device side narrow beam and the remote device side narrow beam based on the combination of narrow beams that maximizes the received power information. the second communication standard is the Bluetooth (registered trademark) standard,
The wireless communication device and the other device are paired,
The wireless communication device according to claim 1 , wherein the wireless communication device and the partner device are time-synchronized at the time of pairing. The wireless communication device according to claim 3 , wherein the wireless communication device acquires, from the other device during the pairing, information regarding the number of narrow beams available in the multi-beam antenna of the other device. The multi-beam antenna of the device itself can use M (M is a positive integer) different narrow beams ,
The wireless communication device according to claim 1, characterized in that the first communication means performs beam sweeping by sequentially switching between m (m is a positive integer greater than or equal to 1 and less than or equal to M) different narrow beams during the initial access operation. The multi-beam antenna of the remote device can use N different narrow beams (N is a positive integer),
The wireless communication device according to claim 5 , characterized in that the first communication means performs the beam sweep on each of n (n is a positive integer greater than or equal to 1 and less than or equal to N) different narrow beams in the multi-beam antenna of the other device. The wireless communication device according to claim 5 , characterized in that the first communication means determines the switching speed of the narrow beam in the beam sweep depending on the accuracy of time synchronization between the wireless communication device and the other device. A control method for a wireless communication device having a first communication means for performing wireless communication based on a first communication standard using radio waves in the terahertz band by utilizing a multi-beam antenna configured to selectively use one narrow beam from a plurality of narrow beams each having a different directivity, and a second communication means for performing wireless communication based on a second communication standard different from the first communication standard,
a transmitting step of transmitting, via the second communication means, setting information to be used in a counterpart device that is communicatively connected via the second communication means during a period in which the first communication means is performing an initial access operation;
a receiving step of receiving, at the other device, information on the other device side obtained in relation to the initial access operation during a period in which the first communication means executes the initial access operation;
a determination step of determining a narrow beam on the local device side to be used by the first communication means in its local device multi-beam antenna and a narrow beam on the remote device side to be used by the remote device multi-beam antenna, based on the remote device side information and the local device side information obtained by the local device regarding the initial access operation during the period in which the initial access operation is performed;
Including,
The device itself and the other device are time-synchronized,
the host device side information includes one or more records associating a narrow beam used in transmission by the host device's multi-beam antenna with time information when the initial access operation is performed,
The counterpart device side information includes one or more records associating a narrow beam used for reception in the counterpart device multi-beam antenna when the initial access operation is executed, time information, and reception power information.
A control method comprising: A program for causing a computer connected to a first communication unit that performs wireless communication based on the first communication standard and a second communication unit that performs wireless communication based on the second communication standard to execute the control method described in claim 8 .