WO2021161473A1

WO2021161473A1 - Wireless communication device, wireless communication system and wireless resource selection method

Info

Publication number: WO2021161473A1
Application number: PCT/JP2020/005648
Authority: WO
Inventors: 紅陽陳
Original assignee: 富士通株式会社
Priority date: 2020-02-13
Filing date: 2020-02-13
Publication date: 2021-08-19

Abstract

A wireless communication device (100) comprises: a determination unit (115) that determines a wireless resource for which sensing is to be skipped in sensing for investigating the status of wireless resources being used by wireless communication devices other than the local device; a sensing unit (116) that executes sensing while skipping the wireless resource determined by the determination unit (115); a selection unit (117) that selects, on the basis of a result of the sensing by the sensing unit (116), a wireless resource to be used for transmitting data; and a transmission unit (113, 130) that transmits the data by use of the wireless resource selected by the selection unit (117).

Description

Wireless communication device, wireless communication system and wireless resource selection method

The present invention relates to a wireless communication device, a wireless communication system, and a wireless resource selection method.

In the current network, the traffic of mobile terminals (smartphones and feature phones) occupies most of the network resources. In addition, the traffic used by mobile terminals tends to increase in the future.

On the other hand, in line with the development of IoT (Internet of Things) services (for example, monitoring systems for transportation systems, smart meters, devices, etc.), it is required to support services with various requirements. Therefore, in the communication standard of the 5th generation mobile communication (5G or NR (New Radio)), in addition to the standard technology of 4G (4th generation mobile communication) (for example, Non-Patent Documents 2 to 12), further There is a demand for technology that realizes high data rates, large capacities, and low delays.

Regarding the 5th generation communication standard, technical studies are underway by the 3GPP working group (for example, TSG-RAN WG1, TSG-RAN WG2, etc.), and the first edition of the standard document was issued in December 2017. (Non-Patent Documents 13 to 39).

As mentioned above, in order to support a wide variety of services, 5G is often classified into eMBB (Enhanced Mobile Broad Band), Massive MTC (Machine Type Communications), and URLLC (Ultra-Reliable and Low Latency Communication). It is supposed to support the use case of.

In addition, the 3GPP working group is also discussing V2X (Vehicle to Everything) communication. V2X is, for example, V2V (Vehicle to Vehicle) that communicates between automobiles using a side link channel, V2P (Vehicle to Pedestrian) that communicates between automobiles and pedestrians, and road infrastructure such as automobiles and signs. It is a general term for V2I (Vehicle to Infrastructure) that communicates between vehicles and V2N (Vehicle to Network) that communicates between automobiles and networks. The provisions regarding V2X are described in, for example, Non-Patent Document 1. In addition, V2X may be described as X2V (Everything to Vehicle). In this case, for example, V2X represents transmitting a signal from the automobile to another device, and X2V represents transmitting a signal from the other device to the automobile.

Regarding resource allocation in V2X, there are an arrangement method in which a control channel (PSCCH: Physical Sidelink Control Channel) and a data channel (PSSCH: Physical Sidelink Shared CHannle) are adjacent to each other, and a method in which the control channel and the data channel are not adjacent to each other. The PSCCH resource is mapped to, for example, SCI (Sidelink Control Information) including information on the modulation method and coding rate of the corresponding PSCCH data.

Further, in V2X, as a method of allocating resources, for example, there are a method of centrally controlling by a mobile communication system and a method of autonomously controlling each terminal device that implements V2X. The method of centrally controlling the mobile communication system is applicable when the terminal device that implements V2X is in the coverage of the mobile communication system, and is also called mode 3 in LTE V2X. On the other hand, the method in which each terminal device autonomously controls is applicable even if the terminal device does not live in the coverage of the mobile communication system, and is also called mode 4 in LTE V2X. In mode 4, since communication between the terminal device for resource allocation and the mobile communication system is not performed, the transmission delay when transmission data is generated in the terminal device is shortened, and a strict delay request is satisfied. Is possible. In mode 4, each terminal device senses the frequency band used for V2X, excludes resources that are likely to be used by other terminal devices based on the sensing result, and selects a resource to be used for data transmission. do.

Note that mode 3 in LTE V2X corresponds to mode 1 of NR (New Radio) -V2X, and mode 4 in LTE V2X corresponds to mode 2 of NR-V2X.

JP-A-2017-139658 International Publication No. 2019/044208

However, there is a problem that power consumption increases when selecting wireless resources in V2X. That is, for example, when the terminal device selects a radio resource to be used for data transmission by sensing, the terminal device continuously performs sensing for a predetermined period of time for all frequency bands used for V2X. In sensing, demodulation and decoding of the control channel, measurement of the received power of the data channel, and the like are executed, so that the processing amount of the terminal device during sensing increases and the power consumption increases.

Further, even when the mobile communication system centrally controls the allocation of wireless resources, the terminal device that receives the data determines whether or not the data addressed to the own device is transmitted by monitoring the control channel. to decide. That is, the terminal device that transmits the data transmits the data using the wireless resource allocated by the mobile communication system, but the terminal device that receives the data constantly monitors the control channel and sends the data addressed to the own device. Judge the presence or absence. Therefore, the power consumption of the terminal device increases due to the demodulation and decoding of the control channel.

The disclosed technology has been made in view of such a point, and an object thereof is to provide a wireless communication device, a wireless communication system, and a wireless resource selection method capable of suppressing an increase in power consumption.

In one embodiment, the wireless communication device disclosed in the present application includes a determination unit that determines a wireless resource to skip sensing in sensing for investigating the usage status of a wireless resource by a wireless communication device other than the own device, and the determination unit. A sensing unit that executes sensing while skipping the wireless resource determined by the sensor, a selection unit that selects a wireless resource to be used for data transmission based on the result of sensing by the sensing unit, and a selection unit that is selected by the selection unit. It has a transmission unit that transmits data using the wireless resources.

According to one aspect of the wireless communication device, the wireless communication system, and the wireless resource selection method disclosed in the present application, it is possible to suppress an increase in power consumption.

FIG. 1 is a diagram showing a configuration example of a wireless communication system according to the first embodiment. FIG. 2 is a block diagram showing a configuration of a terminal device according to the first embodiment. FIG. 3 is a block diagram showing a configuration of a skip control unit according to the first embodiment. FIG. 4 is a flow chart showing a radio resource selection method according to the first embodiment. FIG. 5 is a diagram showing an example of a sensing window. FIG. 6 is a diagram illustrating selection of radio resources. FIG. 7 is a block diagram showing a configuration of a skip control unit according to the second embodiment. FIG. 8 is a flow chart showing a radio resource selection method according to the second embodiment. FIG. 9 is a block diagram showing a configuration of a skip control unit according to the third embodiment. FIG. 10 is a flow chart showing a radio resource selection method according to the third embodiment. FIG. 11 is a diagram showing a configuration example of the wireless communication system according to the fourth embodiment. FIG. 12 is a block diagram showing a configuration of the base station apparatus according to the fourth embodiment. FIG. 13 is a block diagram showing the configuration of the terminal device according to the fourth embodiment.

Hereinafter, embodiments of the wireless communication device, the wireless communication system, and the wireless resource selection method disclosed in the present application will be described in detail with reference to the drawings. The present invention is not limited to this embodiment.

(Embodiment 1)
FIG. 1 is a diagram showing a configuration example of a wireless communication system according to the first embodiment. As shown in FIG. 1, the wireless communication system includes a terminal device V-UE mounted on an automobile and a terminal device P-UE possessed by a pedestrian. The terminal device V-UE and the terminal device P-UE are wireless communication devices capable of wireless communication.

The terminal device V-UE and the terminal device P-UE each group cast data to the terminal devices belonging to the same group. At this time, the terminal device V-UE and the terminal device P-UE autonomously select the radio resource used for transmitting the data. Specifically, the terminal device V-UE and the terminal device P-UE estimate the radio resources used by other devices by sensing all available frequency bands in the sensing window for a predetermined period. Then, the terminal device V-UE and the terminal device P-UE exclude the radio resources estimated to be used by other devices from the timing selection window after the sensing window, and transmit the data. Select the wireless resource to use.

When sensing the radio resource of the sensing window, the terminal device V-UE and the terminal device P-UE each determine the priority level of their own device, and skip the sensing of the radio resource according to the priority level. That is, the terminal device V-UE and the terminal device P-UE do not sense all the radio resources, but sense some radio resources while skipping according to the priority level. As a result, the terminal device V-UE and the terminal device P-UE can suppress an increase in power consumption during sensing.

FIG. 2 is a block diagram showing the configuration of the terminal device 100 which is the same as the terminal device V-UE and the terminal device P-UE. The terminal device 100 shown in FIG. 2 has a processor 110, a memory 120, and a wireless communication unit 130.

The processor 110 includes, for example, a CPU (Central Processing Unit), an FPGA (Field Programmable Gate Array), a DSP (Digital Signal Processor), etc., and controls the entire terminal device 100 in an integrated manner. Specifically, the processor 110 includes a control information generation unit 111, a transmission data generation unit 112, a transmission control unit 113, a reception control unit 114, a skip control unit 115, a sensing unit 116, and a resource selection unit 117.

The control information generation unit 111 generates control information such as SCI. In the control information generated by the control information generation unit 111, information on the data coding rate and modulation method, information for specifying the radio resource of the data channel used for data transmission, and radio resource used for data retransmission are specified. Information to be done is included.

The transmission data generation unit 112 generates transmission data to be transmitted to another terminal device. The transmitted data is group cast to a plurality of terminal devices belonging to the same group as the terminal device 100, for example. Further, the transmission data generation unit 112 generates a presence / absence confirmation request requesting the skip control unit 115 to transmit a presence / absence confirmation signal in order to confirm the existence of surrounding terminal devices in response to an instruction.

The transmission control unit 113 encodes and modulates the control information and transmission data, maps them to radio resources, and generates a transmission signal. At this time, the transmission control unit 113 maps the control information and the transmission data to the radio resource designated by the resource selection unit 117. Then, the transmission control unit 113 causes the wireless communication unit 130 to transmit a transmission signal including control information and transmission data. Further, the transmission control unit 113 causes the wireless communication unit 130 to transmit the existence / absence confirmation request generated by the transmission data generation unit 112.

The reception control unit 114 acquires a received signal from the wireless communication unit 130 and executes reception processing for the received signal. Specifically, the reception control unit 114 executes demodulation and decoding of the control channel to acquire control information, and demodulates and decodes the data channel according to the control information. When the reception control unit 114 receives the presence / absence confirmation signal as a response to the presence / absence confirmation request, the reception control unit 114 outputs the presence / absence confirmation signal to the skip control unit 115.

The skip control unit 115 acquires the presence / absence confirmation signal and calculates the density of the terminal device around the terminal device 100. Then, the skip control unit 115 determines the priority level of sensing in the terminal device 100 according to the density of the terminal device, and instructs the sensing unit 116 of the radio resource for skipping the sensing according to the priority level. At this time, the skip control unit 115 determines that if the density of the terminal device around the terminal device 100 is high, the priority level of sensing is high, and the radio resources skipped in the sensing are reduced. On the other hand, if the density of the terminal device around the terminal device 100 is low, the skip control unit 115 determines that the priority level of sensing is low, and increases the number of radio resources skipped in sensing. The radio resource to be skipped may be, for example, a radio resource arranged periodically, or a radio resource arranged at a position that is a constant multiple of a predetermined period. Further, the cycle of the wireless resource to be sensed may be set so that the wireless resource other than the wireless resource to be sensed is skipped. In this way, the frequency of skipping wireless resources in sensing may be adjusted.

Note that the skip control unit 115 instructs the transmission data generation unit 112 to transmit the existence / absence confirmation request in order to transmit the existence / absence confirmation signal to the terminal devices around the terminal device 100. The detailed configuration of the skip control unit 115 will be described in detail later.

When data to be transmitted is generated, the sensing unit 116 senses the wireless resource in the sensing window and investigates the usage status of the wireless resource. Specifically, the sensing unit 116 demodulates and decodes the control channel in the sensing window using a predetermined number of slots in all frequency bands that can be used for data transmission as the sensing window, and confirms the usage status of the data channel. At the same time, the received power of the data channel in the sensing window is measured. At this time, the sensing unit 116 skips the radio resource instructed by the skip control unit 115 and executes sensing. That is, the sensing unit 116 executes decoding of the control channel and measurement of the received power of the data channel, for example, every other slot in the sensing window according to the instruction from the skip control unit 115.

The resource selection unit 117 selects a wireless resource to be used for data transmission based on the result of sensing by the sensing unit 116. Specifically, the resource selection unit 117 selects a radio resource that is estimated not to be used by another terminal device as a result of sensing from the timing selection window after the sensing window. That is, the resource selection unit 117 selects the radio resource from the selection window by excluding the radio resource that is known to be used by another terminal device as a result of decoding the control channel in the sensing window. .. Further, the resource selection unit 117 selects the radio resource from the selection window by excluding the radio resource that is predicted to be used by another terminal device as a result of measuring the received power of the data channel in the sensing window. do.

The memory 120 includes, for example, a RAM (Random Access Memory) or a ROM (Read Only Memory), and stores information used for processing by the processor 110.

The wireless communication unit 130 transmits / receives signals to / from other terminal devices. Specifically, the wireless communication unit 130 performs a predetermined wireless transmission process on the transmission signal and wirelessly transmits the transmission signal to another terminal device via the antenna. Further, the wireless communication unit 130 wirelessly receives a signal via the antenna and performs a predetermined wireless reception process on the received signal.

FIG. 3 is a block diagram showing the configuration of the skip control unit 115 according to the first embodiment. As shown in FIG. 3, the skip control unit 115 includes a presence / absence confirmation request unit 101, a presence / absence confirmation signal acquisition unit 102, a density calculation unit 103, and a priority level determination unit 104.

The existence / non-existence confirmation request unit 101 instructs the transmission data generation unit 112 to transmit the existence / non-existence confirmation request in order to transmit the existence / non-existence confirmation signal from the terminal devices around the terminal device 100. The existence / non-existence confirmation request unit 101 may instruct the transmission of the existence / non-existence confirmation request when the data to be transmitted is generated, or may instruct the transmission of the existence / non-existence confirmation request at a predetermined cycle. Further, when each terminal device is set in advance to transmit a presence / absence confirmation signal or a signal similar thereto, the presence / absence confirmation request may not be transmitted from the terminal device 100. In this case, the presence / absence confirmation request unit 101 is also unnecessary.

The presence / absence confirmation signal acquisition unit 102 acquires the presence / absence confirmation signal transmitted from another terminal device and received by the wireless communication unit 130. The presence / absence confirmation signal includes, for example, identification information of the terminal device of the transmission source, type information indicating whether the terminal device of the transmission source is a terminal device mounted on an automobile or a terminal device possessed by a pedestrian, and a transmission source. Information on the moving speed and moving direction of the terminal device of the above may be included.

The density calculation unit 103 estimates the distance between the terminal device that is the source of the presence / absence confirmation signal and the terminal device 100, and calculates the density of the terminal device around the terminal device 100. That is, the density calculation unit 103 calculates the propagation loss from the received power of the presence / absence confirmation signal, and estimates the distance to the terminal device of the transmission source based on the propagation loss. Then, the density calculation unit 103 calculates the density of the terminal device around the terminal device 100 from the number of terminal devices whose distance from the terminal device 100 is included in the predetermined range.

The priority level determination unit 104 determines the priority level of sensing in the terminal device 100 according to the density of the terminal device around the terminal device 100. Specifically, the priority level determination unit 104 determines that the higher the density of the surrounding terminal devices, the higher the priority level of sensing, and the lower the density of the surrounding terminal devices, the lower the priority level of sensing. do. Then, the priority level determination unit 104 determines the radio resource to be skipped in the sensing window according to the priority level of sensing, and instructs the sensing unit 116 to skip the sensing of the determined radio resource. At this time, the priority level determination unit 104 reduces the number of radio resources to be skipped as the priority level is higher, and increases the number of radio resources to be skipped as the priority level is lower.

Next, the resource selection method by the terminal device 100 configured as described above will be described with reference to the flow chart shown in FIG.

When data to be transmitted is generated in the terminal device 100, or at a predetermined cycle, the existence / absence confirmation request unit 101 instructs the transmission data generation unit 112 to confirm the existence of surrounding terminal devices, and the transmission data generation unit The existence confirmation request is generated by 112. The existence confirmation request is transmitted from the antenna via the transmission control unit 113 and the wireless communication unit 130 (step S101).

The presence / absence confirmation request is received by the terminal devices around the terminal device 100, and these terminal devices transmit a presence / absence confirmation signal as a response to the presence / absence confirmation request. The presence / absence confirmation signal transmitted from the surrounding terminal device is received by the wireless communication unit 130 (step S102), and is acquired by the presence / absence confirmation signal acquisition unit 102 via the reception control unit 114.

Then, the density calculation unit 103 calculates the density of the terminal device around the terminal device 100 using the presence / absence confirmation signal (step S103). Specifically, for example, the propagation loss is calculated from the received power of the presence / absence confirmation signal, and the distance from the terminal device of the source of the presence / absence confirmation signal to the terminal device 100 is estimated. Then, the density of the terminal device around the terminal device 100 is calculated from the number of the terminal devices located within a predetermined distance from the terminal device 100. The calculated density is notified to the priority level determination unit 104.

Then, the priority level determination unit 104 determines the priority level of sensing according to the density of the surrounding terminal devices (step S104). Specifically, if the density of surrounding terminal devices is high, there is a high possibility that a collision will occur in the selection of wireless resources, so it is judged that the priority level of sensing is high. On the other hand, if the density of surrounding terminal devices is low, it is judged that the priority level of sensing is low because the possibility of collision in selecting wireless resources is low.

When the priority level of sensing is determined, the radio resource to skip sensing is determined according to the priority level. That is, the higher the priority level, the less radio resources are skipped, and the lower the priority level, the more radio resources are skipped. The skipping of the determined radio resource is instructed from the priority level determination unit 104 to the sensing unit 116.

Then, the sensing unit 116 executes sensing of the radio resource while skipping the instructed radio resource (step S105). Specifically, the decoding of the control channel and the reception power measurement of the data channel are executed for the sensing window having a predetermined time width for all the frequency bands that can be used for data transmission. The sensing window includes, for example, a plurality of subchannels sch # 0 to # 3 in the frequency direction and a plurality of slots # 0 to # n in the time direction, as shown in FIG. Of these, according to the instruction from the priority level determination unit 104, for example, the sensing of slots # 1, # 3, # 5, # 7, and # 9 indicated by hatching in the figure is skipped, and the control channels of the other slots are decoded. At the same time, the received power of the data channel is measured.

In this way, the radio resources in the sensing window are sensed while being skipped according to the instruction from the priority level determination unit 104. In other words, decoding the control channel in the sensing window and measuring the received power of the data channel is omitted for some radio resources. Therefore, the processing amount related to sensing can be reduced, and the increase in power consumption can be suppressed.

When the wireless resource sensing in the sensing window is executed, the resource selection unit 117 selects the wireless resource to be used for data transmission (step S106). Specifically, for example, as shown in FIG. 6, the selection window 152 is set at a timing after the sensing window 151, and the radio resources estimated to be used by other terminal devices are excluded from the sensing result. , The radio resource in the selection window 152 is selected. That is, as a result of decoding the control channel in the sensing window 151, the radio resource found to be used by the other terminal device and the received power of the data channel in the sensing window 151 are measured, and as a result, the other terminal device. The radio resources in the selection window 152 are selected, excluding the radio resources presumed to be used by.

The selected radio resource is notified to the transmission control unit 113, and control information and transmission data are mapped to this radio resource. Then, the transmission signal obtained by the mapping is transmitted from the antenna via the wireless communication unit 130 (step S107).

As described above, according to the present embodiment, the density of the surrounding terminal devices is calculated using the presence / absence confirmation signal transmitted from the surrounding terminal devices, and sensing is executed while skipping wireless resources according to the density. do. Therefore, sensing is not executed for all the wireless resources in the sensing window, the processing amount related to sensing can be reduced, and the increase in power consumption can be suppressed.

(Embodiment 2)
The feature of the second embodiment is that the priority level of sensing is determined according to the distance to the nearest terminal device.

Since the configuration of the wireless communication system and the terminal device 100 according to the second embodiment is the same as that of the first embodiment (FIGS. 1 and 2), the description thereof will be omitted. In the second embodiment, the configuration of the skip control unit 115 is different from that of the first embodiment.

FIG. 7 is a block diagram showing the configuration of the skip control unit 115 according to the second embodiment. In FIG. 7, the same parts as those in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted. As shown in FIG. 7, the skip control unit 115 includes a presence / absence confirmation request unit 101, a presence / absence confirmation signal acquisition unit 102, a shortest distance calculation unit 201, and a priority level determination unit 202.

The shortest distance calculation unit 201 estimates the distance between the terminal device of the source of the existence confirmation signal and the terminal device 100, and calculates the shortest distance to the terminal device closest to the terminal device 100. That is, the shortest distance calculation unit 201 calculates, for example, the propagation loss from the received power of the presence / absence confirmation signal, and estimates the distance to the terminal device of the transmission source based on the propagation loss. Then, the shortest distance calculation unit 201 specifies the shortest distance closest to the terminal device 100 from the distance to the terminal device of the transmission source of each presence / absence confirmation signal. In other words, the shortest distance calculation unit 201 specifies the distance to the terminal device located closest to the terminal device 100 as the shortest distance.

The priority level determination unit 202 determines the priority level of sensing in the terminal device 100 according to the shortest distance from the terminal device 100. Specifically, the priority level determination unit 202 determines that the smaller the shortest distance, the higher the priority level of sensing, and the larger the shortest distance, the lower the priority level of sensing. Then, the priority level determination unit 202 determines the radio resource to be skipped in the sensing window according to the priority level of sensing, and instructs the sensing unit 116 to skip the sensing of the determined radio resource. That is, the priority level determination unit 202 reduces the number of radio resources to be skipped as the priority level is higher, and increases the number of radio resources to be skipped as the priority level is lower.

Next, the resource selection method by the terminal device 100 configured as described above will be described with reference to the flow chart shown in FIG. In FIG. 8, the same parts as those in FIG. 4 are designated by the same reference numerals, and detailed description thereof will be omitted.

When data to be transmitted is generated in the terminal device 100, or at a predetermined cycle, a presence / absence confirmation request is transmitted (step S101). The presence / absence confirmation request is received by the terminal devices around the terminal device 100, and these terminal devices transmit a presence / absence confirmation signal in response to the presence / absence confirmation request. The presence / absence confirmation signal transmitted from the surrounding terminal device is received by the wireless communication unit 130 (step S102), and is acquired by the presence / absence confirmation signal acquisition unit 102 via the reception control unit 114.

Then, the shortest distance calculation unit 201 calculates the shortest distance to the terminal device closest to the terminal device 100 using the presence / absence confirmation signal (step S201). Specifically, for example, the propagation loss is calculated from the received power of the presence / absence confirmation signal, and the distance from the terminal device of the source of the presence / absence confirmation signal to the terminal device 100 is estimated. Then, among the plurality of terminal devices that have transmitted the presence / absence confirmation signal, the terminal device having the shortest distance to the terminal device 100 is specified, and the distance to this terminal device is the shortest distance. The shortest distance is notified to the priority level determination unit 202.

Then, the priority level determination unit 202 determines the priority level of sensing according to the shortest distance (step S202). Specifically, if the shortest distance is small, there is a possibility that highly urgent data transmission / reception may occur, and since the certainty of sensing is required, it is judged that the priority level of sensing is high. On the other hand, if the shortest distance is large, it is unlikely that highly urgent data transmission / reception will occur, so it is judged that the priority level of sensing is low.

When the priority level of sensing is determined, the radio resource to skip sensing is determined according to the priority level. That is, the higher the priority level, the less radio resources are skipped, and the lower the priority level, the more radio resources are skipped. The skipping of the determined radio resource is instructed from the priority level determination unit 202 to the sensing unit 116.

Then, the sensing unit 116 executes sensing of the radio resource while skipping the instructed radio resource (step S105). That is, the radio resources in the sensing window are sensed while being skipped according to the instruction from the priority level determination unit 202. Therefore, the processing amount related to sensing can be reduced, and the increase in power consumption can be suppressed.

When the wireless resource sensing in the sensing window is executed, the resource selection unit 117 selects the wireless resource to be used for data transmission (step S106). The selected radio resource is notified to the transmission control unit 113, and control information and transmission data are mapped to this radio resource. Then, the transmission signal obtained by the mapping is transmitted from the antenna via the wireless communication unit 130 (step S107).

As described above, according to the present embodiment, the shortest distance to the nearest terminal device is calculated using the presence / absence confirmation signal transmitted from the surrounding terminal device, and the radio resource is set according to the shortest distance. Perform sensing while skipping. Therefore, sensing is not executed for all the wireless resources in the sensing window, the processing amount related to sensing can be reduced, and the increase in power consumption can be suppressed.

(Embodiment 3)
The feature of the third embodiment is that the priority level of sensing is determined according to the channel busy ratio (CBR: Channel Busy Ratio).

Since the configuration of the wireless communication system and the terminal device 100 according to the third embodiment is the same as that of the first embodiment (FIGS. 1 and 2), the description thereof will be omitted. In the third embodiment, the configuration of the skip control unit 115 is different from that of the first embodiment.

FIG. 9 is a block diagram showing the configuration of the skip control unit 115 according to the third embodiment. As shown in FIG. 9, the skip control unit 115 includes a CBR calculation unit 301 and a priority level determination unit 302.

The CBR calculation unit 301 acquires the sensing result when sensing is executed without skipping from the sensing unit 116, and calculates the CBR from the sensing result. That is, the CBR calculation unit 301 acquires the sensing result executed before the sensing unit 116 receives the skip instruction. This sensing result indicates whether or not all the radio resources in the sensing window are being used by other terminal devices. Therefore, the CBR calculation unit 301 calculates the ratio of the radio resources being used by the other terminal device as the CBR among the radio resources of the entire sensing window.

The priority level determination unit 302 determines the priority level of sensing in the terminal device 100 according to the CBR. Specifically, the priority level determination unit 302 determines that the larger the CBR, the higher the priority level of sensing, and the smaller the CBR, the lower the priority level of sensing. Then, the priority level determination unit 302 determines the radio resource to be skipped in the sensing window according to the priority level of sensing, and instructs the sensing unit 116 to skip the sensing of the determined radio resource. That is, the priority level determination unit 302 reduces the number of radio resources to be skipped as the priority level is higher, and increases the number of radio resources to be skipped as the priority level is lower.

Next, the resource selection method by the terminal device 100 configured as described above will be described with reference to the flow chart shown in FIG. In FIG. 10, the same parts as those in FIG. 4 are designated by the same reference numerals, and detailed description thereof will be omitted.

Before the skip control unit 115 instructs the skip control unit 115 to skip the radio resource, the sensing unit 116 sets the sensing window at a predetermined cycle, for example, and executes sensing of all the radio resources in the sensing window (step S301). The sensing result is acquired by the CBR calculation unit 301, and the ratio of the radio resources being used by another terminal device in the sensing window is calculated as CBR (step S302). The calculated CBR is notified to the priority level determination unit 302.

Then, the priority level determination unit 302 determines the priority level of sensing according to the CBR (step S303). Specifically, if the CBR is large, there is a high possibility that a collision will occur in the selection of radio resources, so it is judged that the priority level of sensing is high. On the other hand, if the CBR is small, it is judged that the priority level of sensing is low because the possibility of collision occurring in the selection of radio resources is small.

When the priority level of sensing is determined, the radio resource to skip sensing is determined according to the priority level. That is, the higher the priority level, the less radio resources are skipped, and the lower the priority level, the more radio resources are skipped. The skipping of the determined radio resource is instructed from the priority level determination unit 302 to the sensing unit 116.

Then, the sensing unit 116 executes sensing of the radio resource while skipping the instructed radio resource (step S105). That is, the radio resources in the sensing window are sensed while being skipped according to the instruction from the priority level determination unit 302. Therefore, the processing amount related to sensing can be reduced, and the increase in power consumption can be suppressed.

As described above, according to the present embodiment, the channel busy ratio in the sensing window is calculated from the sensing result executed without skipping, and the sensing is executed while skipping the radio resource according to the channel busy ratio. .. Therefore, sensing is not executed for all the wireless resources in the sensing window, the processing amount related to sensing can be reduced, and the increase in power consumption can be suppressed.

It should be noted that the above embodiments 1 to 3 can be carried out in combination as appropriate. That is, the priority level of sensing may be determined by combining two or more CBRs in the density of surrounding terminal devices, the shortest distance to the nearest terminal device, and the sensing result executed without skipping. ..

Further, in the above-described first to third embodiments, the sensing is skipped in units of slots in the time direction, but the skip does not necessarily have to be in units of slots. That is, for example, sensing may be skipped in units of sub-channels in the frequency direction, or sensing may be skipped in different time cycles in each sub-channel.

(Embodiment 4)
In the first to third embodiments, the case where the terminal device is not connected to the mobile communication system and autonomously selects a wireless resource to transmit data has been described. However, even when the mobile communication system allocates wireless resources to the terminal device, it is possible to suppress an increase in power consumption.

When the terminal device performs wireless communication using the side link, the transmitting terminal device requests the mobile communication system to allocate wireless resources, and transmits data using the wireless resources allocated by the mobile communication system. I have something to do. At this time, the terminal device on the transmitting side transmits the control information for designating the destination of the data to the control channel of the radio resource allocated by the mobile communication system. The terminal device on the receiving side constantly monitors the control channel used in the side link, and receives the data of the corresponding data channel when the control information indicating that there is data destined for the own device is obtained.

However, since the terminal device on the receiving side constantly monitors the control channel used in the side link, the power consumption increases. Therefore, in the fourth embodiment, a case of suppressing an increase in power consumption in a wireless communication system to which wireless resources are allocated by a mobile communication system will be described.

FIG. 11 is a diagram showing a configuration example of the wireless communication system according to the fourth embodiment. As shown in FIG. 11, the wireless communication system includes a terminal device V-UE mounted on an automobile, a terminal device P-UE possessed by a pedestrian, and a base station device 200 of a mobile communication system.

The terminal device V-UE and the terminal device P-UE each request the base station device 200 to allocate wireless resources when transmitting data to other terminal devices. Then, the terminal device V-UE and the terminal device P-UE transmit data using the radio resources allocated by the base station device 200. Further, the terminal device V-UE and the terminal device P-UE provide control information for specifying the radio resource used for transmitting the data addressed to the own device when the data addressed to the own device is transmitted from the other terminal device. Received from the base station device 200. Then, the terminal device V-UE and the terminal device P-UE receive the data transmitted from the other terminal device to the own device according to the control information received from the base station device 200.

FIG. 12 is a block diagram showing the configuration of the base station apparatus 200 according to the fourth embodiment. The base station apparatus 200 shown in FIG. 12 includes a wireless communication unit 210, a processor 220, and a memory 230.

The wireless communication unit 210 transmits and receives signals to and from a terminal device belonging to the wireless communication system. Specifically, the wireless communication unit 210 performs a predetermined wireless transmission process on the transmission signal and wirelessly transmits the transmission signal to the terminal device via the antenna. Further, the wireless communication unit 210 wirelessly receives a signal via the antenna and performs a predetermined wireless reception process on the received signal.

The processor 220 includes, for example, a CPU, FPGA, DSP, etc., and controls the entire base station apparatus 200 in an integrated manner. Specifically, the processor 220 includes a reception control unit 221, a side link control unit 222, a control information generation unit 223, a transmission data generation unit 224, and a transmission control unit 225.

The reception control unit 221 acquires a reception signal from the wireless communication unit 210 and executes reception processing for the reception signal. Specifically, the reception control unit 221 demodulates and decodes the control channel including the request for allocation of radio resources by the terminal device. Then, the reception control unit 221 outputs the radio resource allocation request to the side link control unit 222.

The side link control unit 222 controls communication by side links between terminal devices belonging to the wireless communication system. Specifically, the side link control unit 222 allocates the radio resource for data transmission to the terminal device in response to the request for allocation of the radio resource from the terminal device. Then, the side link control unit 222 notifies the control information generation unit 223 of the information for identifying the allocated radio resource for data transmission.

The control information generation unit 223 generates the first control information including the information that identifies the radio resource assigned to the terminal device for data transmission. This first control information includes information that identifies the control channel and the data channel used by the terminal device that transmits the data. The control information generation unit 223 also generates second control information to be transmitted to the terminal device of the data reception destination. This second control information includes information that identifies the data channel to which the data reception destination is the destination. Further, the second control information may include wake-up information for activating the terminal device in sleep mode.

The transmission data generation unit 224 generates transmission data when data to be transmitted to the terminal device is generated.

The transmission control unit 225 encodes and modulates the first control information, the second control information, and the transmission data, maps them to the radio resource, and generates a transmission signal. Specifically, the transmission control unit 225 maps the first control information to, for example, individual PDCCHs (Physical Downlink Control Channels), and maps the second control information to group PDCCHs for a plurality of terminal devices that receive data. do. Then, the transmission control unit 225 causes the wireless communication unit 210 to transmit a transmission signal including the first control information, the second control information, and the transmission data.

The memory 230 includes, for example, a RAM or a ROM, and stores information used for processing by the processor 220.

FIG. 13 is a block diagram showing a configuration of a terminal device 100 that receives data transmitted from another terminal device using a side link. In FIG. 13, the same parts as those in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted. The terminal device 100 shown in FIG. 13 has a processor 110 having a configuration different from that of the terminal device 100 shown in FIG. That is, the processor 110 includes a network reception control unit 411, a resource identification unit 412, and a side link reception control unit 413.

The network reception control unit 411 acquires the reception signal received from the base station device 200 from the wireless communication unit 130, and executes reception processing for the reception signal. Specifically, the network reception control unit 411 executes demodulation and decoding of the control channel including the second control information. Then, the network reception control unit 411 outputs the second control information to the resource identification unit 412. The network reception control unit 411 activates the sleeping terminal device 100 when the terminal device 100 is operating even during the sleep and the second control information includes the wakeup information.

The resource specifying unit 412 specifies the radio resource of the data channel destined for the terminal device 100 with reference to the second control information. That is, the resource specifying unit 412 specifies the radio resource of the data channel to which the data addressed to the terminal device 100 is transmitted, which is the radio resource allocated by the base station device 200 for the communication using the side link.

The side link reception control unit 413 acquires a received signal received from another terminal device using the side link from the wireless communication unit 130, and executes reception processing for the received signal. Specifically, the side link reception control unit 413 demodulates and decodes the data channel specified by the resource identification unit 412. At this time, the side link reception control unit 413 executes demodulation and decoding of the control channel corresponding to the data channel, and executes demodulation and decoding of the data channel according to the obtained control information.

In the present embodiment, the terminal device that transmits data using the side link requests the base station device 200 to allocate the radio resource, and the base station device 200 allocates the radio resource and then first. The control information is transmitted to the terminal device from which the data is transmitted. On the other hand, the base station device transmits the second control information including the information of the allocated radio resource to the terminal device 100 of the data reception destination. Therefore, the terminal device 100 can specify the radio resource used for transmitting data to its own device from the second control information without constantly monitoring the control channel used in the side link. As a result, the power for monitoring the control channel can be reduced and the increase in power consumption can be suppressed.

As described above, according to the present embodiment, the base station device allocates radio resources to the communication using the side link, and transmits the first control information for identifying the allocated radio resources to the terminal device of the data transmission source. At the same time, the second control information is also transmitted to the terminal device of the data receiving destination. Then, the terminal device of the data receiving destination identifies the radio resource including the data addressed to its own device from the second control information, and executes the receiving process. Therefore, the terminal device of the data receiving destination does not need to constantly monitor the control channel used in the side link, and can reduce the power related to the monitoring of the control channel and suppress the increase in power consumption.

110 Processor 111 Control information generation unit 112 Transmission data generation unit 113 Transmission control unit 114 Reception control unit 115 Skip control unit 116 Sensing unit 117 Resource selection unit 120 Memory 130 Wireless communication unit 101 Presence / absence confirmation request unit 102 Presence / absence confirmation signal acquisition unit 103 Density Calculation unit 104, 202, 302 Priority level determination unit 201 Shortest distance calculation unit 301 CBR calculation unit

Claims

A decision unit that determines the wireless resource to skip sensing in sensing that investigates the usage status of wireless resources by wireless communication devices other than the own device, and
A sensing unit that executes sensing while skipping the radio resources determined by the determination unit, and
A selection unit that selects wireless resources to be used for data transmission based on the result of sensing by the sensing unit, and a selection unit.
A wireless communication device including a transmission unit that transmits data using a wireless resource selected by the selection unit.
The decision unit
It has a calculation unit that calculates the density of wireless communication devices other than its own device.
The wireless communication device according to claim 1, wherein the higher the calculated density, the smaller the number of wireless resources for which sensing is skipped.
The decision unit
It has a calculation unit that calculates the distance from its own device to another wireless communication device.
The wireless communication device according to claim 1, wherein the smaller the calculated distance, the smaller the number of wireless resources for which sensing is skipped.
The sensing unit
Executes sensing without skipping for wireless resources under predetermined conditions,
The decision unit
It has a calculation unit that calculates the ratio indicating the ratio of wireless resources in use by other wireless communication devices from the result of sensing executed without skipping.
The wireless communication device according to claim 1, wherein the higher the calculated ratio, the smaller the number of wireless resources for which sensing is skipped.
The sensing unit
The wireless communication device according to claim 1, wherein the usage status of the data channel is confirmed by decoding the control channel, and the received power of the data channel is measured.
The control channel
PSCCH (Physical Sidelink Control CHannel)
The data channel
The wireless communication device according to claim 5, wherein the wireless communication device is a PSSCH (Physical Sidelink Shared CHannel).
A wireless communication system including a first wireless communication device and a second wireless communication device capable of wireless communication with the first wireless communication device.
The first wireless communication device is
A determination unit for determining the wireless resource to be skipped in sensing for investigating the usage status of the wireless resource by another wireless communication device including the second wireless communication device, and a determination unit.
A sensing unit that executes sensing while skipping the radio resources determined by the determination unit, and
A selection unit that selects wireless resources to be used for data transmission based on the result of sensing by the sensing unit, and a selection unit.
A wireless communication system including a transmission unit that transmits data using a radio resource selected by the selection unit.
A wireless resource selection method performed by a wireless communication device.
Investigate the usage status of wireless resources by other wireless communication devices Determine the wireless resources to skip sensing in sensing
Perform sensing while skipping determined radio resources,
Based on the sensing results, select the radio resources to use to send the data,
A radio resource selection method comprising a process of transmitting data using a selected radio resource.