WO2020031355A1

WO2020031355A1 - Terminal device and radio communication system

Info

Publication number: WO2020031355A1
Application number: PCT/JP2018/029998
Authority: WO
Inventors: 紅陽陳; ジヤンミンウー; 剛史下村
Original assignee: 富士通株式会社
Priority date: 2018-08-09
Filing date: 2018-08-09
Publication date: 2020-02-13
Also published as: JPWO2020031355A1

Abstract

The terminal device has a determination unit, a generation unit, a transmission unit, and an allocation unit. Upon detection of a transmission request for high-priority data to be directly communicated to another terminal device, the determination unit determines whether or not there are sufficient resources for allocation to the data transmission requested in the transmission request from among a plurality of resources which can be allocated for data transmission. When sufficient resources are not available for allocation to the data transmission of the transmission request of the transmission request, the generation unit selects resources reserved for other terminal devices for data transmissions lower in priority than the priority level of the data transmission of the transmission request and generates a command for requesting release of the selected reserved resources. The transmission unit transmits the command generated by the generation unit to each of the other terminal devices. The allocation unit allocates the resources released by the other terminal devices in response to the command to the data transmission of the transmission request. As a result, it is possible to satisfy the service requirement for the allowable maximum delay time corresponding to the data transmission of the transmission request.

Description

Terminal device and wireless communication system

<< The present invention relates to a terminal device and a wireless communication system.

In the current network, for example, traffic of mobile terminals such as smartphones and future 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, along with the development of IoT (Internet of Things) services, for example, services such as monitoring systems such as traffic systems, smart meters, and devices, it is required to support services with various requirements. . Therefore, in the communication standard of the fifth generation mobile communication (5G or NR (New @ Radio)), in addition to the standard technology of 4G (fourth generation mobile communication) (for example, Non-Patent Documents 2 to 12), higher communication standards are used. There is a need for a technology that achieves a higher data rate, larger capacity, and lower delay. Technical studies on the fifth generation communication standard are being conducted by 3GPP working groups (eg, TSG-RAN @ WG1, TSG-RAN @ WG2, etc.) (Non-Patent Documents 13 to 39).

As described above, 5G is classified into eMBB (Enhanced Mobile Broadband), Massive MTC (Machine Type Communications), and URLLC (Ultra-Reliable and Low Latency Communication) in order to support a wide variety of services. It is intended to support many use cases. The 3GPP Working Group is also discussing V2X (Vehicle to Everything) communication. The 3GPP Working Group is also discussing D2D (Device to Device) communication. D2D communication is sometimes called side link communication. Also, V2X is being studied as an example of D2D communication. The V2X communication is, for example, communication using a side link channel, and includes, for example, V2V (Vehicle to Vehicle) communication, V2P (Vehicle to Vehicle) communication, V2I (Vehicle to Infrastructure) communication, and the like. V2V communication is communication between a car and a car, V2P communication is communication between a car and a pedestrian (Pedestrian), and V2I communication is communication between a car and a road infrastructure such as a sign. The rules regarding V2X are described in Non-Patent Document 1, for example.

As a method of allocating V2X resources of # 4G, for example, there are a method in which a mobile communication system performs centralized control and a method in which each terminal device implementing V2X performs autonomous control. The system in which the mobile communication system performs centralized control is applicable when the terminal device implementing V2X is located in the coverage of the base station of the mobile communication system, and is also referred to as mode 3. On the other hand, the method in which each terminal device controls autonomously is applicable even if the terminal device does not exist in coverage of the base station, and is also referred to as mode 4. In mode 4, communication for allocating resources between the terminal device and the base station is not performed.

端末 Each terminal device in mode 4 senses the entire frequency band used for V2X communication. When detecting a packet transmission request, each terminal device selects a resource to be allocated to packet transmission based on a result of sensing. Upon detecting the packet transmission request, the terminal device sets the time width in the selection window according to the allowable maximum delay time allowable for packet transmission. Then, the terminal device sets a resource which is likely to be used by another terminal device in the selection window to be reserved, based on a sensing result from a point in time when the transmission request is detected until a predetermined period before. Then, the terminal device refers to the selection window, selects a free resource other than the reserved resource in the selection window, and allocates the selected free resource to packet transmission of the transmission request and transmits the packet.

However, the current resource allocation method may not be able to satisfy the service requirements of V2X (for example, NR-V2X) currently discussed in 3GPP. For example, when a transmission request for a packet requiring a low delay occurs, as a result of the sensing processing, the available resources for transmitting the transmission request packet are insufficient, the transmission request packet cannot be transmitted, and the service requirement is reduced. Can not be satisfied.

For example, in the terminal device in the mode 4, the time width of the selection window is set according to the allowable maximum delay time of the packet transmission. Therefore, when the transmission request of the high priority packet is detected, the allowable maximum delay of the high priority packet transmission is detected. Since the time is shortened, the time width of the selection window is also shortened. Further, as the time width of the selection window becomes shorter, the amount of resources that can be allocated to packet transmission of a transmission request in the selection window also becomes smaller. As a result, the high priority packet cannot be transmitted within the allowable maximum delay time of the high priority packet due to the decrease in the resource amount, and the service requirement is not satisfied.

The disclosed technology has been made in view of the above, and has as its object to satisfy a request for an allowable maximum delay time according to a packet transmission of a transmission request.

端末 A terminal device according to one aspect includes a determination unit, a generation unit, a transmission unit, and an assignment unit. When detecting a transmission request for high-priority data that directly communicates with another terminal device, the determination unit determines that there is a shortage of resources to be allocated to data transmission of the transmission request among a plurality of resources that can be allocated to data transmission. Is determined. The generating unit selects a resource reserved by another terminal device used for data transmission lower than the priority level of the data transmission of the transmission request when resources allocated to data transmission of the transmission request are insufficient, Generate a command to request release of the selected reserved resource. The transmitting unit transmits the command generated by the generating unit to each of the other terminal devices. The allocating unit 44 allocates resources released by other terminal devices to data transmission of a transmission request in response to the command.

In one aspect, the service requirement of the maximum allowable delay time according to the packet transmission of the transmission request can be satisfied.

FIG. 1 is an explanatory diagram illustrating an example of the wireless communication system according to the first embodiment. FIG. 2 is an explanatory diagram illustrating an example of the sensing window and the selection window. FIG. 3 is an explanatory diagram showing an example when the time width of the selection window changes according to the allowable maximum delay time of the transmission packet. FIG. 4 is a block diagram illustrating an example of the mobile station according to the first embodiment. FIG. 5 is a block diagram illustrating an example of a function of the V2V scheduler unit of the mobile station according to the first embodiment. FIG. 6 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the first embodiment. FIG. 7 is a flowchart illustrating an example of a processing operation of the mobile station related to the transmission-side assignment processing according to the first embodiment. FIG. 8 is a flowchart illustrating an example of a processing operation of the mobile station related to the receiving-side release processing according to the first embodiment. FIG. 9 is an explanatory diagram illustrating an example of the wireless communication system according to the second embodiment. FIG. 10 is a flowchart illustrating an example of a processing operation of the member station related to the member-side assignment processing according to the second embodiment. FIG. 11 is a flowchart illustrating an example of a processing operation of the head station related to the head-side assignment processing according to the second embodiment. FIG. 12 is a flowchart illustrating an example of a processing operation of the member station related to the member-side release processing according to the second embodiment. FIG. 13 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the third embodiment. FIG. 14 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the fourth embodiment. FIG. 15 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the fifth embodiment. FIG. 16 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the sixth embodiment. FIG. 17 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the seventh embodiment. FIG. 18 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the eighth embodiment. FIG. 19 is an explanatory diagram showing an example of an SCI format including information on a mute sign. FIG. 20 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the ninth embodiment. FIG. 21 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the tenth embodiment.

Hereinafter, this embodiment will be described in detail with reference to the drawings. The problems and examples in this specification are merely examples, and do not limit the scope of the present application. In particular, even if the expressions described are different, as long as they are technically equivalent, the technology of the present application can be applied to different expressions, and the scope of rights is not limited. The embodiments can be appropriately combined within a range that does not contradict processing contents.

The terms and technical contents described in this specification may be the terms and technical contents described in specifications and contributions as communication standards such as 3GPP as appropriate. Such a specification is, for example, the above-mentioned 3GPPGPTS 38.211 V15.1.0 (2018-03).

Hereinafter, embodiments of the terminal device and the wireless communication system disclosed in the present application will be described in detail with reference to the drawings. The following embodiments do not limit the disclosed technology.

FIG. 1 is an explanatory diagram illustrating an example of the wireless communication system 1 according to the first embodiment. The wireless communication system 1 illustrated in FIG. 1 includes a plurality of mobile stations 2 and a base station 3. In the wireless communication system 1, for example, LTE-V2V (Long Term Evolution-Vehicle to vehicle) is a resource allocation method for arranging the mobile station 2 in a vehicle and realizing direct communication between the mobile stations 2. The resource allocation method of V2V communication includes, for example, mode 3 and mode 4.

無線 In the wireless communication system 1A used in mode 3, the present invention is applicable when the base station 3 controls resources intensively and the mobile station 2 performing V2V communication is located in the coverage of the base station 3. Further, in the wireless communication system 1B used in the mode 4, each mobile station 2 performing V2V communication controls autonomously, and the present invention is applicable even if the mobile station 2 does not exist in the coverage of the base station 3.

移動 Each mobile station 2 in the wireless communication system 1B used in mode 4 senses a frequency band used for V2V communication. Specifically, the mobile station 2 receives the SCI (Side Link Control Channel) of the entire frequency band used for V2V communication during a predetermined sensing period, and measures the reception power of the corresponding subchannel. Then, the mobile station 2 determines whether or not another mobile station 2 is transmitting a signal in each subframe and subchannel. When detecting a transmission request for packet transmission, the mobile station 2 excludes resources that are likely to be used by other mobile stations 2 based on the sensing result, and selects a free resource to be allocated to packet transmission. When the mobile station 2 in mode 4 detects a transmission request for packet transmission, it sets the time width of the selection window according to the allowable maximum delay time of the transmission packet. Then, based on the sensing result, the mobile station 2 sets a resource that is likely to be used by another mobile station 2 as a reserved resource in the selection window. Then, the mobile station 2 selects a free resource other than the reserved resource in the selection window, and allocates packet transmission to the selected free resource.

FIG. 2 is an explanatory diagram showing an example of the sensing window and the selection window. The sensing window and the selection window illustrated in FIG. 2 are an example of the sensing window and the selection window of the V2V communication of the mobile station 2 of the UE 3 of the mode 4 wireless communication system 1B, for example. The sensing window is a sensing result of receiving a PSCCH (Physical Side Link Control Channel) in a frequency band used for V2V communication, and capturing the usage status of resources of the mobile station 2 from the SCI in the PSCCH. As the resource, for example, three sub-channels are arranged for every 1 msec slot, and each sub-channel has control information as a V2V control signal and data as a V2V data signal. For example, the mobile station 2 of the UE 3 can know the reserved resources of each subchannel from the SCI in each PSCCH of the entire frequency band used for V2V communication. The reason why the reserved resources of each subchannel are known from the SCI is that information included in the SCI can be decoded (decoded). Note that the UE 3 can measure PSSCH-RSRP and S-RSSI (side link RSSI) and can select one resource based on the measurement result. The mobile station 2 of the UE 3 executes a sensing process of capturing a resource use state of another mobile station 2 based on a measurement result of whether or not the received power of each sub-channel exceeds a predetermined threshold. The sensing window illustrated in FIG. 2 is a sensing result captured by the mobile station 2 of the UE 3 and indicates resources used by the mobile stations 2 of the UE 1 and the UE 2. When detecting the packet transmission request, the mobile station 2 of the UE 3 sets the time width of the packet transmission selection window, and based on the sensing result up to 1000 ms before the detection of the transmission request, the mobile station 2 of the UE 1 and the UE 2 Set a reserved resource in the selection window. The mobile station 2 of the UE 3 selects a free resource other than the reserved resources in the selection window, and allocates a packet transmission of a transmission request to the selected free resource.

As described above, upon detecting a packet transmission request, the mobile station 2 changes the time width of the selection window according to the allowable maximum delay time of packet transmission. Note that, for example, the allowable maximum delay time specified in LTE is, for example, 20 ms to 100 ms, and the time width of the selected window is also 20 ms to 100 ms.

Further, based on the sensing result, when the reserved resources in the selection window become 80% or more, the mobile station 2 increases the predetermined threshold value of the received power of the resources of each sub-channel to 3 dB, thereby making the use state of the resources highly accurate. Will be captured. As a result, the mobile station 2 can recognize the use state of the resource within the selection window with high accuracy. The mobile station 2 randomly selects an available resource from the selection window, and allocates a packet transmission of a transmission request to the selected resource.

However, R16 @ NR-V2X has services of Advanced @ V2X, such as platooning, advanced driving, extended sensors and remote driving. The platooning is, for example, a service in which a plurality of vehicles on which the mobile stations 2 are mounted automatically travel in a platoon. The advanced driving is, for example, a service such as a support system for preventing a running vehicle equipped with the mobile station 2 from departing from the lane. The extended sensor is a service that uses, for example, a sensor result detected by a vehicle equipped with the mobile station 2 in another vehicle equipped with another mobile station 2. The remote driving is, for example, a driving service by remote control of a vehicle on which the mobile station 2 is mounted.

Service requirements for advanced driving include, for example, a payload of 2000 bytes, a maximum allowed delay (Max３end to end Latency) of 3 ms, a reliability of 99.999%, a data rate of 30 Mbps, and a minimum wireless range of 500 meters. Wireless conditions are required. For the extended sensor, for example, wireless conditions are required such that the maximum allowable delay time is 3 ms, the reliability is 99.999%, the data rate is 50 Mbps, and the minimum wireless range is 200 meters.

FIG. 3 is an explanatory diagram showing an example when the time width of the selection window changes according to the allowable maximum delay time of the transmission packet. For example, in order to satisfy a service condition of 3 ms, which is an allowable maximum delay time of a high-priority packet, it is necessary to shorten the time width of the selection window from 100 ms to 3 ms as shown in FIG. However, for example, when the time width of the selection window is shortened according to the allowable maximum delay time of the high-priority packet, the number of resources in the selection window decreases, and the number of resources available in the selection window decreases. As a result, the V2V mobile station 2 may be unable to transmit a high-priority packet.

Therefore, even when the time width of the selection window is shortened according to the allowable maximum delay time of the high-priority packet, the mobile station 2 is required to secure resources to be allocated to the high-priority packet and satisfy the service requirements. .

FIG. 4 is a block diagram illustrating an example of the mobile station 2 according to the first embodiment. The mobile station 2 illustrated in FIG. 2 includes a cellular antenna 11, a cellular receiving unit 12, a cyclic prefix (CP) removing unit 13, a fast Fourier transform (FFT) unit 14, a decoding unit 15, a scheduler 15, and a scheduler. A part 16. Further, the mobile station 2 includes a data generating unit 17, a data encoding unit 18, an IFFT (Inverse Fast Fourier Transform) unit 19, a CP adding unit 20, and a cellular transmitting unit 21. Further, the mobile station 2 includes a V2V antenna 22, a V2V receiving unit 23, a V2V control decoding unit 24, a V2V data decoding unit 25, a mute indication decoding unit 26, a V2V scheduler unit 27, and a resource pool 28. Have. The mobile station 2 has a V2V control generation unit 29, a V2V data generation unit 30, a mute sign generation unit 31, and a V2V transmission unit 32.

The cellular antenna 11 transmits and receives a radio signal of a radio carrier used for the mode 3 radio communication system 1A, for example. The cellular receiving unit 12 receives a radio signal through the cellular antenna 11, and performs a radio reception process such as down-conversion and A / D conversion on the received signal. CP removing section 13 removes the CP added to the received signal in symbol units. Then, CP removing section 13 outputs the received signal after the CP removal to FFT section 14. The FFT unit 14 performs a fast Fourier transform on the received signal output from the CP removing unit 13, and converts a time-domain received signal into a frequency-domain received signal. The received signal includes data, a control signal, and the like transmitted from the base station 3. The decoding unit 15 demodulates and decodes data from the received signal in the frequency domain converted by the FFT unit 14. The decoding unit 15 demodulates and decodes the control signal from the converted frequency-domain received signal.

The scheduler unit 16 performs scheduling for allocating radio resources to data transmitted to and received from the base station 3. Specifically, the scheduler unit 16 performs uplink scheduling from the mobile station 2 to the base station 3, which allocates radio resources to data transmitted by each mobile station 2. The scheduler unit 16 performs scheduling of a downlink from the base station 3 to the mobile station 2.

The data generation unit 17 generates data to be transmitted to the base station 3. The data encoding unit 18 encodes and modulates the generated data, and outputs the modulated data to the IFFT unit 19. The IFFT unit 19 performs an inverse fast Fourier transform on the data output from the data generation unit 17, and converts a transmission signal in the frequency domain into a transmission signal in the time domain. Then, IFFT section 19 outputs the transmission signal in the time domain to CP adding section 20. CP adding section 20 adds a CP to the transmission signal output from IFFT section 19 in symbol units. Then, CP adding section 20 outputs the transmission signal to which the CP has been added to cellular transmitting section 21. The cellular transmission unit 21 performs radio transmission processing such as D / A conversion and up-conversion on the transmission signal, and transmits the radio signal through the cellular antenna 11.

The V2V antenna 22 transmits and receives, for example, a V2V communication wireless signal used for the mode 4 wireless communication system 1B. The V2V receiving unit 23 receives a wireless signal through the V2V antenna 22, and performs a wireless receiving process such as down-conversion and A / D conversion on the received signal. The V2V control decoding unit 24 decodes a V2V control signal included in the reception signal received and processed by the V2V reception unit 23. The V2V control signal is control information in a sub-channel in the PSSCH in the received signal. The V2V data decoding unit 25 decodes a V2V data signal included in the reception signal received and processed by the V2V reception unit 23. The V2V data signal is data in a sub-channel in the PSSCH in the received signal. The mute sign decoding unit 26 decodes the mute sign included in the reception signal processed by the V2V reception unit 23. The mute indication is control information such as a command stored in a predetermined cycle in the received signal. The mute indication is a command for requesting each mobile station 2 to release a specific reserved resource, which will be described later in detail.

The V2V scheduler unit 27 executes scheduling for allocating resources used for V2V communication to data transmitted / received to / from the V2V mobile station 2. The resource pool 28 manages the use status of resources used for V2V communication, for example, information such as a sensing window and a selection window. The V2V control generation unit 29 generates a V2V control signal to be transmitted to the destination mobile station 2, for example, a sub-channel control information. The V2V data generation unit 30 generates a V2V data signal to be transmitted to the destination mobile station 2, for example, sub-channel data. The mute sign generation unit 31 generates a mute sign to be broadcast-transmitted to each mobile station 2. The V2V transmission unit 32 converts the V2V transmission signal including the V2V control signal generated by the V2V control generation unit 29 and the V2V data signal generated by the V2V data generation unit 30 into radio signals such as D / A conversion and up-conversion. Execute transmission processing. Then, the V2V transmission unit 32 transmits the V2V wireless signal after the execution of the wireless transmission process through the V2V antenna 22. The V2V transmission unit 32 performs wireless transmission processing such as D / A conversion and up-conversion on the mute sign generated by the mute sign generation unit 31, and broadcasts the mute sign to each mobile station 2 via the V2V antenna 22.

FIG. 5 is a block diagram illustrating an example of a function of the V2V scheduler unit 27 of the mobile station 2 according to the first embodiment. The V2V scheduler unit 27 reads a program stored in a ROM (Read Only Memory) (not shown), and executes the read program, so that, for example, the determination unit 41, the generation unit 42, the transmission unit 43, the allocation unit The functions of 44 and the opening unit 45 are executed. When detecting the transmission request of the high-priority packet, the determination unit 41 determines whether there is insufficient free resources to be used for high-priority packet transmission among a plurality of resources that can be allocated to V2V communication, based on the sensing result. Is determined. The generation unit 42 selects a resource reserved by another mobile station 2 in low-priority packet transmission in which the priority level of packet transmission is lower when free resources used for high-priority packet transmission are insufficient. I do. Further, the generation unit 42 controls the mute sign generation unit 31 to generate a mute sign requesting release of the selected resource. The mute indication includes resource information for identifying a resource to be muted which requests release of the selected resource. For the mute indication, for example, among the PSCCHs including the CRC, a PSSCH having a monitoring period described later is used. The mute indicator has the same size (for example, a 16-bit or 32-bit configuration) as the SCI of control information and the like. In order to clarify the difference between the SCI of the mute indication and other SCIs, RNTI (Radio Network Temporary Identifier) is stored in the SCI of the mute indication. Note that the mobile station 2 receiving the mute indication can easily identify the SCI of the mute indication by the RNTI in the SCI.

The transmission unit 43 controls the V2V transmission unit 32 to broadcast the generated mute indication to each of the other mobile stations 2. The allocating unit 44 allocates high-priority packet transmission to a free resource released by another mobile station 2 according to the mute indication. The release unit 45 determines whether the resource to be muted in the mute indication received from the other mobile station 2 is a resource reserved by the own station. The release unit 45 releases the reserved resource to be muted when the resource to be muted for the mute indication detected from the other mobile station 2 is the resource reserved by the own station.

FIG. 6 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the first embodiment. The mobile station 2 uses a resource of a predetermined cycle in the same resource as the resource used for the V2V communication as the indication channel for transmitting the mute indication. Then, the mute indication is included in the control information in the resource of the predetermined cycle. The mobile station 2 transmitting the mute indication broadcasts the mute indication to the other mobile stations 2 using the indication channel. Further, the mobile station 2 receiving the mute indication monitors the presence / absence of the mute indication using the indication channel of a predetermined cycle as a monitoring cycle. As described above, since the same resource is used as the V2V communication during the period of the indication channel, V2V communication cannot be performed. For convenience of explanation, the mobile station 2 transmitting the mute indication is the mobile station 2A, and the mobile station 2 of the mobile station 2 receiving the mute indication, in which the resource to be muted in the mute indication has been reserved by its own station, moves. Station 2B.

When the mobile station 2A detects a packet transmission request, the mobile station 2A captures a resource use state by another mobile station 2 based on a sensing result from the time when the transmission request is detected to a time 1000 ms before. The mobile station 2A sets the time width of the selection window according to the permissible maximum delay time of the transmission of the transmission request packet, and the available resources of the other mobile stations 2 are insufficient for the transmission of the transmission request packet. Is determined. The mobile station 2A allocates a free resource to the transmission data of the transmission request when there is no shortage of the free resource used for transmitting the transmission request packet.

{Circle around (2)} When the available resources used for transmitting the transmission request packet are insufficient, the mobile station 2A selects the reserved resource having the lower priority level of the transmission request as the resource to be muted. The mobile station 2A broadcasts a mute indication including resource information for identifying the selected resource to be muted to another mobile station 2 through the indication channel.

In addition, when the mobile station 2 receiving the mute indication receives the mute indication through the indication channel, the mobile station 2 decodes the mute indication, extracts the resource information in the mute indication, and specifies the resource to be muted from the resource information. Further, the mobile station 2 determines whether or not the resource to be muted is a resource that has been reserved by the own station. Further, among the mobile stations 2 that have received the mute indication, the mobile station 2B releases the reserved resources since the resources to be muted are the resources reserved by the own station.

{Circle around (2)} The mobile station 2A that has transmitted the mute indication allocates the packet transmission of the transmission request to the vacant resource to be muted released by the mobile station 2B according to the mute indication. As a result, the mobile station 2A can allocate resources to transmission of a transmission request packet even if there are no or insufficient free resources due to resources reserved for low-priority packet transmission, for example.

For example, when the mobile station 2A of the UE 10 detects the transmission request of the high-priority packet as shown in FIG. 6, based on the sensing result from the time when the transmission request was detected to 1000 ms before, the resource of the other mobile station 2 Capture usage of. Further, the mobile station 2A of the UE 10 sets the time width of the selection window according to the allowable maximum delay time of the high-priority packet transmission, and uses the empty space to be used for the high-priority packet of the transmission request based on the usage status of the other mobile stations 2. Determine whether resources are insufficient.

Since the mobile station 2A of the UE 10 lacks the free resources used for the high-priority packet of the transmission request, the priority level of the transmission of the packet of the transmission request is lower than the high priority and the reserved resource of the lower priority is lower than the high priority based on the sensing result. Is selected as a resource to be muted. Note that the priority level of packet transmission of the mobile station 2A of the UE 10 is high priority, and the priority level of packet transmission used for resources reserved by the mobile station 2 of the UE 2 is low priority. Therefore, the mobile station 2A of the UE 10 selects the reserved resource of the mobile station 2B of the low-priority UE 2 having the lower priority of the packet transmission of the transmission request as the resource to be muted from the sensing result. Then, the mobile station 2A of the UE 10 generates a mute indication including resource information for identifying the selected resource to be muted. The mobile station 2A of the UE 10 broadcasts a mute indication to each of the other mobile stations 2 at the timing of the indication channel monitoring cycle.

When the mobile station 2B of the UE 2 detects the mute indication at the timing of the monitoring cycle, the mobile station 2B decodes the mute indication to extract the resource information, and specifies the resource to be muted from the extracted resource information. The mobile station 2B of the UE 2 releases the reserved resource because the resource indicated by the mute is a resource reserved by the own station.

Further, after transmitting the mute indication, the mobile station 2A of the UE 10 allocates the high-priority packet transmission of the transmission request to the free resources to be muted released by the mobile station 2A of the UE 2 according to the mute indication. As a result, the mobile station 2A of the UE 10 can realize high-priority packet transmission.

Next, the operation of the mode 4 wireless communication system 1B of the wireless communication system 1 according to the first embodiment will be described. FIG. 7 is a flowchart illustrating an example of a processing operation of the mobile station 2A related to the transmission-side assignment processing according to the first embodiment. The mobile station 2A on the transmitting side determines whether or not the transmission request of the mobile station has been detected (step S11). The transmission request is, for example, a request for requesting transmission of a packet by the own station. If the mobile station 2A detects its own transmission request (Yes at step S11), the mobile station 2A determines whether the priority level of packet transmission of the transmission request is high priority (step S12). As described above, the priority levels are, for example, two levels of high priority and low priority.

When the priority level of the packet transmission of the transmission request is high priority (Yes at Step S12), the mobile station 2A determines from the sensing result whether the free resources used for the transmission of the high priority packet of the transmission request are insufficient. (Step S13). If there is not enough free resources to use for high-priority packet transmission (Yes at Step S13), the mobile station 2A continues monitoring the sensing window (Step S14). The mobile station 2A selects a resource to be muted in the selection window based on the sensing result (step S15).

The mobile station 2A generates a mute indication including resource information for identifying the selected resource to be muted (step S16). The mobile station 2A broadcasts the generated mute indication to each mobile station 2 on the indication channel shown in FIG. 6 (step S17). As a result, for example, when the mobile station 2B receives the mute indication from the mobile station 2A, the mobile station 2B releases the reserved resources because the resources to be muted in the mute indication are resources reserved by the own station. become. Then, the mobile station 2A allocates the resource to be muted to the packet transmission of the transmission request, executes the packet transmission (step S18), and ends the processing operation illustrated in FIG.

If the priority level of packet transmission of the transmission request is not high priority (No at Step S12), the mobile station 2A continues monitoring the sensing window (Step S19). Then, the mobile station 2A selects an available resource in the selection window based on the sensing result (step S20). Then, the mobile station 2A allocates the packet transmission of the transmission request to the selected resource, executes the packet transmission (step S21), and ends the processing operation illustrated in FIG. If the available resources are not insufficient (No at Step S13), the mobile station 2A determines that there is available resources that can be used for packet transmission of the transmission request, and proceeds to Step S19 to continue monitoring the sensing window. I do. If the mobile station 2A does not detect its own transmission request (No at Step S11), the mobile station 2A continues monitoring the sensing window (Step S22), and ends the processing operation illustrated in FIG.

When detecting the transmission request of the high-priority packet, the mobile station 2A executing the transmission-side allocation process shown in FIG. 7 determines whether there is insufficient free resources to use for transmitting the high-priority packet of the transmission request based on the sensing result. Determine whether or not. When the available resources are insufficient, the mobile station 2A selects a low-priority reserved resource having a lower priority level, and displays a mute indication including the selected reserved resource in the resources to be muted to each mobile station 2. Broadcast transmission. Further, the mobile station 2A allocates a high-priority packet transmission of a transmission request to a muted free resource released by the mobile station 2B according to the mute indication. As a result, the mobile station 2 can realize high-priority packet transmission even when the available resources are insufficient.

FIG. 8 is a flowchart illustrating an example of a processing operation of the mobile station 2 related to the receiving side release processing according to the first embodiment. The mobile station 2 on the receiving side determines whether or not the current time is the monitoring cycle of the mute indication (step S31). The monitoring cycle is a cycle at which the mute sign can be transmitted or received. If the current period is the monitoring period (Yes at Step S31), the mobile station 2 determines whether or not there is a mute indication from the mobile station 2A within the monitoring period (Step S32). When there is a mute indication within the monitoring period (Yes at Step S32), the mobile station 2 determines whether or not there is a resource reserved by the mobile station 2 (Step S33). If there is a resource reserved in the mobile station 2 (Yes in step S33), the mobile station 2 decodes the mute indication to identify the resource to be muted from the resource information, and the resource reserved in the mobile station is the resource to be muted. Is determined (step S34). If the resource reserved by the mobile station 2 is a resource to be muted (Yes at step S34), the mobile station 2 releases the resource reserved by the mobile station 2 to be muted (step S35), and the processing operation shown in FIG. To end.

If the mobile station 2 is not in the monitoring cycle of the mute indication (No at Step S31), or if there is no mute indication within the monitoring cycle (No at Step S32), the mobile station 2 continues monitoring the sensing window (Step S36), as shown in FIG. The processing operation ends. In addition, when there is no reserved resource (No in step S33), or when the resource reserved in the mobile station is not the resource to be muted in the mute indication (No in step S34), the mobile station 2 is illustrated in FIG. The processing operation ends.

When detecting the mute indication, the mobile station 2 executing the receiving side release processing shown in FIG. 8 identifies the resource to be muted from the resource information in the mute indication, and replaces the resource reserved in its own station with the resource to be muted. Is determined. When the resource reserved by the mobile station 2 is a resource to be muted, the mobile station 2 releases the reserved resource to be muted. As a result, the mobile station 2A that has transmitted the mute indication can allocate the packet transmission of the transmission request to the free resource released according to the mute indication.

When detecting the transmission request of the high-priority packet, the mobile station 2 in the mode 4 of the first embodiment determines, based on the sensing result, whether or not the available resources used for transmitting the high-priority packet of the transmission request are insufficient. judge. If there are not enough free resources to use for high-priority packet transmission, the mobile station 2 selects a low-priority reserved resource and generates a mute indication that includes the selected reserved resource as a mute target resource. . Further, the mobile station 2 broadcasts the generated mute indication to each mobile station 2 on the indication channel. Further, the mobile station 2 allocates a high-priority packet transmission of a transmission request to a muted free resource released by another mobile station 2 according to the mute indication. As a result, the mobile station 2 can realize high-priority packet transmission in response to the transmission request even when the available resources are insufficient. The service requirement of the allowable maximum delay time according to the packet transmission of the transmission request can be satisfied.

In addition, the mobile station 2 in the mode 4 broadcasts the mute indication to the other mobile stations 2 by using the indication channel which is a resource of a predetermined period in the resources used for the V2V communication. As a result, the mobile station 2 that receives the mute indication can also capture the mute indication of the indication channel while performing normal V2V communication sensing because the indication channel uses the resources of V2V communication.

In the wireless communication system 1B in the mode 4 of the first embodiment, the case where the master and the slave of the mobile station 2 are not set is illustrated. However, for example, each mobile station 2 traveling in a vehicle platoon forms a group, and one mobile station 2 in the group is a head station 2C, and other mobile stations 2 other than the head station 2C are

member stations

2D, 2E, 2F. Therefore, an embodiment of the wireless communication system 1B having such a master-slave relationship will be described below as a second embodiment. The same components as those of the wireless communication system 1 according to the first embodiment are denoted by the same reference numerals, and the description of the overlapping configurations and operations will be omitted.

FIG. 9 is an explanatory diagram illustrating an example of the wireless communication system 1 according to the second embodiment. In the vehicle platooning, each mobile station 2 forms a group. One mobile station 2 in the group functions as a head station 2C, and other mobile stations 2 other than the head station 2C function as

member stations

2D, 2E, and 2F. The

member stations

2D, 2E, and 2F other than the head station 2C are, for example, a member station 2D that has requested high-priority packet transmission and a member station 2E that releases its reserved resources according to the mute indication. , And the member station 2F in which the resource to be muted is unused.

(4) When the member station 2D detects a transmission request for a high-priority packet, the member station 2D captures the resource usage status of another mobile station 2 based on the sensing result up to 1000 ms before the detection of the transmission request. The member station 2D sets the time width of the selection window according to the maximum permissible delay time of the transmission request, and due to the usage status of the other mobile stations 2, there is a shortage of free resources to be used for transmitting the transmission request with high priority. Is determined. If there is no shortage of free resources, the member station 2D allocates free resources to high-priority packet transmission of the transmission request.

Further, when there is a shortage of free resources to be used for high-priority packet transmission, the member station 2D selects a low-priority reserved resource having a lower priority level of packet transmission of the transmission request as a resource to be muted. . The member station 2D transmits a mute request including resource information for identifying the selected resource to be muted to the head station 2C.

When the head station 2C detects the mute request from the member station 2D, the head station 2C broadcasts a mute indication including the resource information in the mute request to another mobile station (member station) 2 through the indication channel. When receiving the mute indication, the mobile station (member station) 2 receives the mute indication through the indication channel, decodes the mute indication, and specifies the resource to be muted from the resource information in the mute indication. Further, the mobile station (member station) 2 determines whether or not the resource to be muted is a resource reserved by the mobile station. Further, the mobile station 2, for example, the member station 2E releases the reserved resource when the resource to be muted is a resource reserved by the own station.

{Circle around (2)} The member station 2D that has transmitted the mute request allocates the high-priority packet transmission of the transmission request to the mute target free resource released by the member station 2E according to the mute indication. As a result, the member station 2D allocates a high-priority packet transmission to the free resource even when the free resource is insufficient in the selection window.

Next, the operation of the wireless communication system 1B of mode 4 in the wireless communication system 1 of the second embodiment will be described. FIG. 10 is a flowchart illustrating an example of a processing operation of the member station 2D related to the member-side assignment processing according to the second embodiment. The member station 2D determines whether the transmission request of the own station has been detected (step S41). The transmission request is, for example, a request for requesting transmission of a packet. If the member station 2D detects its own transmission request (Yes at step S41), the member station 2D determines whether the priority level of packet transmission of the transmission request is high priority (step S42). The priority levels are, for example, two levels of high priority and low priority.

When the priority level of the packet transmission of the transmission request is high priority (Yes at Step S42), the member station 2D determines whether or not there is insufficient free resources to be used for transmitting the high priority packet of the transmission request (Step S42). S43). If there is not enough free resources to use for high-priority packet transmission (Yes at Step S43), the member station 2D continues monitoring the sensing window (Step S44). The member station 2D selects a resource to be muted in the selection window based on the sensing result (step S45).

The member station 2D transmits a mute request including the selected resource to be muted to the head station 2C (step S46). As a result, the head station 2C generates a mute indication in response to the mute request, and broadcasts the generated mute indication to each mobile station (member station) 2. Then, if the resource to be muted in the received mute indication is a resource reserved by the own station, the mobile station 2 (member station 2E) releases the reserved resource. Then, the member station 2D allocates the resource to be muted released by the member station 2E to the high-priority packet transmission of the transmission request, executes the packet transmission (step S47), and ends the processing operation illustrated in FIG.

If the priority level of packet transmission of the transmission request is not high priority (No at Step S42), the member station 2D continues monitoring the sensing window (Step S48). The member station 2D selects an available resource in the selection window based on the sensing result (step S49). Then, the member station 2D allocates the packet transmission of the transmission request to the selected resource, executes the packet transmission (step S50), and ends the processing operation illustrated in FIG. If there is no shortage of free resources to be used for high-priority packet transmission (No at step S43), the member station 2D determines that there is a free resource that can be allocated to packet transmission of the transmission request, and monitors the sensing window. The process moves to step S48 in order to continue. In addition, when the member station 2D does not detect its own transmission request (No at Step S41), the monitoring of the sensing window is continued (Step S51), and the processing operation illustrated in FIG. 10 ends.

When detecting the transmission request of the high-priority packet, the member station 2D executing the member-side allocation processing shown in FIG. 10 determines whether or not there is insufficient free resources to be used for the high-priority packet of the transmission request based on the sensing result. Is determined. When the available resources are insufficient, the member station 2D selects a reserved resource of low priority, sets the selected reserved resource as a resource to be muted, and issues a mute request including the resource to be muted to the head station 2C. Send to The member station 2D allocates a high-priority packet transmission of a transmission request to a mute target free resource released by the member station 2E according to the mute indication from the head station 2C. As a result, the member station 2D can execute high-priority packet transmission in response to the transmission request even when the available resources are insufficient.

FIG. 11 is a flowchart illustrating an example of a processing operation of the head station 2C related to the head-side assignment processing according to the second embodiment. The head station 2C determines whether a transmission request of the head station has been detected (step S61). The transmission request is, for example, a request for requesting transmission of a packet. When the head station 2C detects its own transmission request (Yes at Step S61), the head station 2C determines whether or not the priority level of packet transmission of the transmission request is high priority (Step S62). The priority levels are, for example, two levels of high priority and low priority.

When the priority level of the packet transmission of the transmission request is high priority (Yes at Step S62), the head station 2C determines whether or not there is not enough free resources to use for the high priority packet transmission of the transmission request (Step S62). S63). When the available resources are insufficient (step S63: YES), the head station 2C continues monitoring the sensing window (step S64). The head station 2C selects a resource to be muted in the selection window based on the sensing result (step S65).

The head station 2C generates a mute indication including resource information for identifying the selected resource to be muted (step S66). The head station 2C broadcasts the generated mute indication to each mobile station (member station) 2 that is a member station (step S67). As a result, the mobile station (member station) 2 receives the mute indication from the head station 2C, and releases the reserved resource when the resource to be muted in the mute indication is a resource reserved by the own station. become. The head station 2C allocates the resource to be muted to the high-priority packet transmission of the transmission request, executes the packet transmission (step S68), and ends the processing operation illustrated in FIG.

If the priority level of the transmission request is not high priority (No at Step S62), the head station 2C continues monitoring the sensing window (Step S69) and selects an available resource in the selection window based on the sensing result. (Step S70). Then, the head station 2C allocates the selected resource to the packet transmission of the transmission request, executes the packet transmission (step S71), and ends the processing operation illustrated in FIG.

If there is no shortage of free resources (No at step S63), the head station 2C determines that there is free resources available for packet transmission of the transmission request, and proceeds to step S69 to continue monitoring the sensing window. I do.

If the head station 2C does not detect its own transmission request (No at Step S61), the head station 2C determines whether a mute request from the member station 2D has been detected (Step S72). When the head station 2C detects the mute request from the member station 2D (Yes at Step S72), the head station 2C determines whether the priority level of the packet transmission of the transmission request related to the mute request is high priority (Step S73). When the priority level of the packet transmission of the transmission request related to the mute request is high priority (Yes at Step S73), the head station 2C generates a mute indication including the resource to be muted in the mute request (Step S74). Further, the head station 2C broadcasts the mute indication to each mobile station (member station) 2 (step S75), and ends the processing operation shown in FIG. If the priority level of the packet transmission of the transmission request related to the mute request is not high priority (No at Step S73), the head station 2C continues monitoring the sensing window (Step S76) and ends the processing operation illustrated in FIG.

ヘッド When the head station 2C executing the head-side assignment processing shown in FIG. 11 receives a mute request related to a high-priority transmission request from the member station 2D, it generates a mute indication including resource information in the mute request. The head station 2C broadcasts the generated mute indication to each mobile station (member station) 2. As a result, the member station 2D allocates high-priority packet transmission to a mute target free resource released by the member station 2E according to the mute indication. As a result, the member station 2D can execute high-priority packet transmission in response to the transmission request even when the available resources are insufficient.

FIG. 12 is a flowchart illustrating an example of a processing operation of the member station 2E related to the member-side release processing according to the second embodiment. The member station 2E determines whether or not the current time is the monitoring cycle of the mute indication (step S81). The monitoring cycle is a cycle for monitoring the mute sign. If the current period is the monitoring period (Yes at Step S81), the member station 2E determines whether or not there is a mute indication from the head station 2C within the monitoring period (Step S82). When there is a mute indication within the monitoring period (Yes at Step S82), the member station 2E determines whether there is a resource reserved at its own station (Step S83). If there is a resource reserved at the own station (Yes at Step S83), the member station 2E identifies the resource to be muted from the resource information by decoding the mute indication, and the resource reserved at the local station is the resource to be muted. Is determined (step S84).

If the resource reserved by the own station is a resource to be muted (Yes at Step S84), the member station 2E releases the reserved resource that is a resource to be muted (Step S85), and performs the processing operation shown in FIG. finish. The member station 2E continues monitoring the sensing window (step S86) when it is not in the monitoring cycle of the mute sign (No in step S81) or when there is no mute sign in the monitoring cycle (no in step S82), as shown in FIG. The processing operation ends. When there is no reserved resource (No at Step S83), or when the resource reserved at the own station is not a resource to be muted (No at Step S84), the member station 2E proceeds to Step S86 to continue monitoring. Transition.

When detecting the mute indication, the member station 2E executing the member-side release processing shown in FIG. 12 specifies the resource to be muted from the resource information in the mute indication, and replaces the resource reserved in its own station with the resource to be muted. Is determined. The member station 2E releases the reserved resource to be muted when the resource reserved at the own station is the resource to be muted. As a result, the member station 2D that has transmitted the mute indication can allocate and transmit the packet transmission of the transmission request to the free resource released according to the mute indication.

When the member station 2D in the mode 4 of the second embodiment detects the transmission request of the high-priority packet, based on the sensing result, the member station 2D determines whether or not the available resources used for transmitting the high-priority packet of the transmission request are insufficient. judge. When the available resources are insufficient, the member station 2D selects a low-priority reserved resource, sets the selected reserved resource as a resource to be muted, and sends a mute request including the resource to be muted to the head station 2C. Send. When receiving the mute request from the member station 2D, the head station 2C broadcasts a mute indication including the resource to be muted in the mute request to each mobile station (member station) 2. The member station 2E releases the reserved resource according to the mute indication, when the resource to be muted is the resource reserved by the own station. Then, the member station 2D allocates a high-priority packet transmission to a muted target free resource released by the member station 2E according to the mute indication. As a result, the member station 2D can execute high-priority packet transmission in response to the transmission request even when the available resources are insufficient.

In the first and second embodiments, the case where the priority level of the packet transmission is two levels of the high priority and the low priority is exemplified. However, the priority level is not limited to the two levels. It can be changed as appropriate. For example, an embodiment in which the priority levels of packet transmission are set to three levels will be described below as a third embodiment. The same components as those of the first embodiment are denoted by the same reference numerals, and the description of the same components and operations will not be repeated.

FIG. 13 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the third embodiment. The priority levels of the packet transmission are, for example, three levels of LV1 to LV3. LV1 is the packet transmission with the highest priority level, LV2 is the packet transmission with the second priority level, and LV3 is the third priority. Packet transmission. The maximum allowable delay time of packet transmission of LV1 is, for example, 3 msec, the maximum allowable delay time of packet transmission of LV2 is, for example, 10 msec, and the maximum allowable delay time of packet transmission of LV3 is, for example, 15 msec.

For example, when the mobile station 2A of the UE 10 detects the transmission request of the packet transmission of the LV1 as illustrated in FIG. 13, the mobile station 2A of the other mobile station 2 based on the sensing result up to 1000 ms before the detection of the transmission request. Capture resource usage. Further, the mobile station 2A of the UE 10 sets the time width of the selection window according to the allowable maximum delay time of the transmission request of 3 ms, and the available resources used for transmitting the packet of the LV1 are insufficient due to the usage status of the other mobile stations 2. It is determined whether or not.

The mobile station of the UE 10 selects a reserved resource of LV2 or LV3 lower than the packet transmission priority level (LV1) as a resource to be muted because the available resources used for transmitting the packet of LV1 are insufficient. . Note that the priority level of packet transmission of the mobile station 2A of the UE 10 is "LV1", and the priority level of packet transmission used by the mobile station 2 of the UE 2 for reserved resources is "LV3". Therefore, the mobile station 2A of the UE 10 selects the reserved resource of the mobile station 2 of the UE 2 of the LV 3 lower than the priority level LV1 of the packet transmission of the transmission request as the resource to be muted. Then, the mobile station 2A of the UE 10 generates a mute indication including resource information for identifying the selected resource to be muted.

The mobile station 2A of the UE 10 broadcasts a mute indication to each of the other mobile stations 2 at the timing of the monitoring cycle in the indication channel. When the mobile station 2B of the UE 2 receives the mute indication at the timing of the monitoring cycle, the mobile station 2B decodes the mute indication and specifies the resource to be muted from the resource information. The mobile station 2B of the UE 2 releases the reserved resource because the resource to be muted is the resource reserved by the own station.

(4) Further, after transmitting the mute indication, the mobile station 2A of the UE 10 allocates the packet transmission of the transmission request LV1 to the empty resource to be muted released by the mobile station 2A of the UE 2 according to the mute indication. As a result, the mobile station 2A of the UE 10 can execute the packet transmission of the LV1.

Also, the mobile station 2A of the UE 10 detects the transmission request of the LV2 packet transmission, and if there is not enough free resources to use the LV2 packet transmission of the transmission request, the UE2 of the LV3 packet transmission lower than the LV2. Of the mobile station 2B that has been reserved. Then, the mobile station 2A of the UE 10 broadcasts a mute indication with the selected resource as a resource to be muted.

移動 Then, the mobile station 2B of the UE2 that has received the mute indication releases the reserved resource of the LV3 when the resource to be muted in the mute indication is a reserved resource. Then, the mobile station 2A of the UE 10 allocates the packet transmission of the transmission request LV2 to the resource released by the mobile station 2B of the UE 2.

Also, in the wireless communication system 1 according to the first embodiment, a case has been exemplified in which the mute indication is broadcast-transmitted to another mobile station 2 using the indication channel which is a resource of a predetermined period in the resources used for the V2V communication. However, since the indication channel of the first embodiment is a part of the resources used for V2V communication, it is necessary to secure resources even when the mute indication is not transmitted. Therefore, it is conceivable that the resource use efficiency of the V2V communication is reduced. Therefore, a mute indication may be broadcast-transmitted to another mobile station 2 by using a resource of a predetermined cycle in a frequency band different from that used for the V2V communication for the indication channel. This will be described below. The same components as those of the wireless communication system according to the first embodiment are denoted by the same reference numerals, and the description of the overlapping configurations and operations will be omitted.

FIG. 14 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the fourth embodiment. The mobile station 2A uses a resource of a predetermined cycle in a frequency band different from a resource used for V2V communication for the indication channel. The mobile station 2A transmitting the mute indication broadcasts the mute indication to the other mobile stations 2 using the indication channel. Further, the mobile station 2B receiving the mute indication monitors the presence / absence of the mute indication using the indication channel as a monitoring cycle. As described above, since the resource of the frequency band different from that of the V2V communication is used during the period of the indication channel, the V2V communication and the mute indication communication can be used at the same time.

When the mobile station 2A detects a packet transmission request, the mobile station 2A captures the resource usage status of the other mobile station 2 based on the sensing result from the time when the transmission request was detected up to 1000 ms before. The mobile station 2A sets a selection window according to the maximum permissible delay time of the transmission request, and determines whether or not there is insufficient free resources to be used for high-priority packet transmission of the transmission request based on the usage status of the other mobile stations 2. Is determined. The mobile station 2A allocates a free resource to the transmission of the high-priority packet of the transmission request when there is no shortage of the free resources to be used for transmitting the high-priority packet of the transmission request.

{Circle around (2)} When the free resources used for transmitting the high-priority packet of the transmission request are insufficient, the mobile station 2A selects the low-priority reserved resource as the resource to be muted. At this time, if the mobile station 2A is using the resource of the V2V communication at the same timing as the monitoring cycle of the indication channel, the mobile station 2A cannot decode the mute indication of the monitoring cycle. Therefore, reserved resources used by the mobile station 2 using V2V communication at the same timing as the monitoring period are excluded from the resources to be muted. That is, since the mobile station 2 cannot simultaneously decode the mute indication of the monitoring period and the SCI of the V2V communication resource at the same timing, the mobile station 2 replaces the reserved resource of the V2V communication at the same timing as the monitoring period with the resource to be muted. Exclude from Then, the mobile station 2A broadcasts a mute indication including resource information for identifying the selected resource to be muted to another mobile station 2 through the indication channel.

{Circle around (2)} The mobile station 2B receiving the mute indication monitors the monitoring cycle of the indication channel, and determines whether or not the mute indication has been received according to the monitoring cycle. When receiving the mute indication, the mobile station 2B decodes the mute indication and identifies the resource to be muted from the resource information. Further, the mobile station 2B determines whether or not the resource to be muted is a resource that has been reserved by the own station. Further, when the resource to be muted is a resource reserved by the own station, the mobile station 2B releases the reserved resource.

{Circle around (2)} Then, the mobile station 2A that has transmitted the mute indication allocates the packet transmission of the transmission request to the free resource to be muted released according to the mute indication. As a result, the mobile station 2A can allocate a free resource to high-priority packet transmission even when there is a shortage of free resources used for transmitting a transmission request packet.

For example, when the mobile station 2A of the UE 10 detects the transmission request of the high-priority packet as shown in FIG. 14, the mobile station 2A of the other mobile station 2 Capture usage of. Further, the mobile station 2A of the UE 10 sets the time width of the selection window according to the maximum allowable delay time of the transmission request, and uses the available resources for transmitting the high-priority packet of the transmission request based on the usage status of the other mobile stations 2. It is determined whether or not is insufficient.

The mobile station 2A of the UE 10 selects a reserved resource with a low priority as a resource to be muted, because there is not enough free resources to use for transmitting a high-priority packet for a transmission request. Note that the priority level of packet transmission of the transmission request of the mobile station 2A of the UE 10 is high priority, for example, the priority level of packet transmission allocated to the reserved resource by the mobile station 2B of the UE 2 is low priority. The mobile station 2A of the UE 10 excludes the resources of the mobile station 2 of the UE2, UE4, and UE5 using the resources at the same timing as the monitoring cycle of the indication channel from the resources to be muted. Accordingly, the mobile station 2A of the UE 10 selects a reserved resource of the mobile station 2B of the low-priority UE 1 having a low priority of transmission of a high-priority packet of a transmission request as a resource to be muted. Then, the mobile station 2A of the UE 10 generates a mute indication including resource information for identifying the selected resource to be muted. The mobile station 2A of the UE 10 broadcasts a mute indication to each of the other mobile stations 2 at the timing of the indication channel monitoring cycle.

When the mobile station 2B of the UE 1 detects the mute indication at the timing of the monitoring cycle, the mobile station 2B decodes the mute indication and specifies the resource to be muted from the resource information. The mobile station 2B of the UE1 releases the reserved resource because the resource to be muted is the resource reserved by the own station.

Further, after transmitting the mute indication, the mobile station 2A of the UE 10 allocates the high-priority packet transmission of the transmission request to the free resource to be muted released by the mobile station 2B of the UE 1 according to the mute indication. As a result, the mobile station 2A of the UE 10 can execute high-priority packet transmission.

In the fourth embodiment, a resource of a predetermined cycle in a frequency band different from that used for V2V communication is used for the indication channel. As a result, since the resources of the V2V communication are not used as compared with the indication channel of the first embodiment, the wireless efficiency of the V2V communication can be improved.

Note that the number of resources to be muted in the mute indication of the fourth embodiment is exemplified as one, but the number is not limited to one, and may be plural, for example, and can be changed as appropriate. is there. An embodiment in which two mute targets are included in the mute indication will be described below as a fifth embodiment. The same components as those in the above embodiment are denoted by the same reference numerals, and the description of the same components and operations will not be repeated.

FIG. 15 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the fifth embodiment. The number of resources to be muted in the mute indication of the fourth embodiment is one, whereas the number of resources to be muted in the mute indication of the fifth embodiment is two. The case where two mute target lists are generated can be assumed, for example, when the head station 2C receives a mute request from the two member stations 2D.

When the member station 2D of the UE 10 detects a transmission request for high-priority packet transmission, it captures the resource usage status of another mobile station 2 based on the sensing result up to 1000 ms before detecting the transmission request. . The member station 2D of the UE 10 sets the time width of the selection window according to the allowable maximum delay time of the high-priority transmission request, and uses the idle state used for transmitting the high-priority packet of the transmission request based on the usage status of the other mobile stations 2. Determine whether resources are insufficient. If there is no shortage of free resources, the member station 2D of the UE 10 allocates free resources to high-priority packet transmission of the transmission request.

In addition, when the available resources are insufficient, the member station 2D of the UE 10 selects a reserved resource of a low priority with a low priority of transmission of a high priority packet of a transmission request as a resource to be muted. The member station 2D of the UE 10 selects, for example, a reserved resource used by the member station 2E of the low-priority UE 1 as a resource to be muted. The member station 2D of the UE 10 transmits to the head station 2C a mute request including resource information for identifying the selected resource to be muted.

When the member station 2D of the UE 11 detects the transmission request of the high-priority packet after the transmission request of the member station 2D of the UE 10 and before the monitoring period, based on the sensing result from the time when the transmission request was detected to 1000 ms before. , The resource usage status of the other mobile station 2 is captured. The member station 2D of the UE 11 sets the time width of the selection window according to the allowable maximum delay time of the transmission request of the high-priority packet, and an available resource used for transmitting the transmission request packet is determined based on the usage status of the other mobile stations 2. Determine if there is a shortage. If there is no shortage of free resources, the member station 2D of the UE 11 allocates free resources to be used for transmitting a transmission request packet.

In addition, when the available resources are insufficient, the member station 2D of the UE 11 selects a reserved resource lower than the priority level of packet transmission of the transmission request as a resource to be muted. The member station 2D of the UE 11 selects, for example, a reserved resource used by the member station 2E of the low-priority UE 7 as a resource to be muted. The member station 2D of the UE 11 transmits a mute request including resource information for identifying the selected resource to be muted to the head station 2C.

When the head station 2C detects the mute request from the member station 2D of the UE 10, the head station 2C extracts the resource information in the mute request. Further, when detecting the mute request from the member station 2D of the UE 10, the head station 2C extracts the resource information in the mute request. Similarly, when detecting the mute request from the member station 2D of the UE 11, the head station 2C extracts the resource information in the mute request. Then, the head station 2C generates a mute indication including the two resources to be muted extracted from the member stations 2D of the UE 10 and the UE 11.

The head station 2C broadcasts a mute indication including two resources to be muted to other mobile stations 2 through the indication channel. When receiving the mute indication through the indication channel, the mobile station 2 decodes the mute indication and specifies the resource to be muted from the resource information. Further, the mobile station 2 determines whether or not the resource to be muted is a resource that has been reserved by the own station. Further, the mobile station 2, for example, the member station 2E of the UE1 and the UE7 releases the reserved resource when the resource to be muted is a resource reserved by the own station.

Then, the member station 2D of the UE 10 that has transmitted the mute request allocates the packet transmission of the transmission request to the empty resource to be muted released by the member station 2E of the UE 1 according to the mute indication. As a result, the member station 2D of the UE 10 allocates resources to the high-priority packet transmission of the transmission request even when the available resources are insufficient in the selection window.

Then, the member station 2D of the UE 11 that has transmitted the mute request allocates the packet transmission of the transmission request to the empty resource to be muted released by the member station 2E of the UE 7 according to the mute indication. As a result, the member station 2D of the UE 11 allocates resources to the high-priority packet transmission of the transmission request even when the available resources are insufficient in the selection window.

In the fifth embodiment, two muted resources can be stored in one mute indication, so that the transmission efficiency of the mute indication can be improved.

In the wireless communication system 1 according to the first embodiment, the case where the mute indication is broadcast-transmitted to another mobile station 2 using the indication channel which is a resource of a predetermined cycle in the resources used for the V2V communication has been exemplified. Furthermore, the case where the number of resources to be muted in the mute sign is one has been exemplified, but a plurality of resources may be used, and an embodiment thereof will be described below as a sixth embodiment. The same components as those in the first to third embodiments are denoted by the same reference numerals, and the description of the overlapping configurations and operations will be omitted.

FIG. 16 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the sixth embodiment. The number of resources to be muted in the mute indication of the first embodiment is one, whereas the number of resources to be muted in the mute indication of the fifth embodiment is, for example, two. For example, a case where two resources to be muted occur occurs when the head station 2C receives a mute request from two member stations 2D. Further, the priority levels of packet transmission are, for example, three levels of LV1 to LV3.

When the member station 2D of the UE 10 detects the transmission request of the packet transmission of the LV1, the member station 2D of the UE 10 captures the resource use status of the other mobile station 2 based on the sensing result up to 1000 ms before the detection of the transmission request. The member station 2D of the UE 10 sets the time width of the selection window according to the allowable maximum delay time of the packet transmission of the LV1, and the available resources used for transmitting the packet of the transmission request LV1 are determined based on the usage status of the other mobile stations 2. Determine if there is a shortage. If there is no shortage of free resources, the member station 2D of the UE 10 allocates free resources to the packet transmission of the LV1.

In addition, when the free resources are insufficient, the member station 2D of the UE 10 selects the reserved resources of the LV3 lower than the priority level (LV1) of the packet transmission of the transmission request as the resources to be muted. The member station 2D of the UE 10 selects, for example, a reserved resource of the LV 3 used by the member station 2E of the UE 2 as a resource to be muted. The member station 2D of the UE 10 transmits to the head station 2C a mute request including resource information for identifying the selected resource to be muted.

Further, when the member station 2D of the UE 11 detects the transmission request of the LV1 after the transmission request of the member station 2D of the UE 10 and before the monitoring period, based on the sensing result from the time when the transmission request was detected to 1000 ms before. , The resource usage status of the other mobile station 2 is captured. The member station 2D of the UE 11 sets the time width of the selection window according to the maximum permissible delay time of the transmission of the transmission request LV1 packet, and uses the time width of the transmission request LV1 packet based on the usage status of other mobile stations 2. It is determined whether or not free resources are insufficient. If there is no shortage of free resources, the member station 2D of the UE 11 allocates free resources to packet transmission of the transmission request LV1.

In addition, when the free resources are insufficient, the member station 2D of the UE 11 selects the reserved resources of the LV3 lower than the priority level (LV1) of the packet transmission of the transmission request as the resources to be muted. The member station 2D of the UE 11 selects, for example, a reserved resource of the LV 3 used by the member station 2E of the UE 1 as a resource to be muted. The member station 2D of the UE 11 transmits a mute request including resource information for identifying the selected resource to be muted to the head station 2C.

When the head station 2C detects the mute request from the member station 2D of the UE 10, the head station 2C extracts the resource information in the mute request and specifies the resource to be muted. Similarly, when detecting the mute request from the member station 2D of the UE 11, the head station 2C extracts the resource information in the mute request. Then, the head station 2C generates a mute indication including two resources to be muted from the member stations 2D of the UE10 and the UE11.

The head station 2C broadcasts a mute indication including two resources to be muted to other mobile stations 2 through the indication channel. When receiving the mute indication, the mobile station (member station) 2 receives the mute indication through the indication channel, decodes the mute indication, and specifies the resource to be muted from the resource information. Further, the mobile station 2 determines whether or not the resource to be muted is a resource that has been reserved by the own station. Further, the mobile station 2, for example, the member station 2E of the UE1 and the UE2 releases the reserved resource when the resource to be muted is a resource reserved by the own station.

Then, the member station 2D of the UE 10 that has transmitted the mute request allocates the transmission request LV1 packet transmission to the muted target free resource of the released UE2 according to the mute indication. As a result, the member station 2D of the UE 10 can execute transmission of the transmission request LV1 packet even when the available resources are insufficient in the selection window.

Then, the member station 2D of the UE 11 that has transmitted the mute request allocates the packet transmission of the transmission request LV1 to the empty resource to be muted released by the member station 2E of the UE 1 according to the mute indication. As a result, the member station 2D of the UE 11 can execute the packet transmission of the transmission request LV1 even when the available resources are insufficient in the selection window.

In addition, since the monitoring cycle of the indication channel has, for example, three sub-channel resources, a mute indication can be stored in the SCI of each sub-channel. Moreover, the mute indication can store up to two resources to be muted. Therefore, in the monitoring cycle of the indication channel, up to six resources to be muted can be transmitted using three subchannels.

In the sixth embodiment, two muted resources can be stored in one mute indication, so that the transmission efficiency of the mute indication can be improved.

In the above embodiment, the case where the mute indication is transmitted using the SCI in the resource for one slot used for V2V communication has been described as an example. However, the resource is not limited to the resource for one slot, and may be a resource for a slot such as a half slot or two slots, for example, and can be changed as appropriate.

The mute indication in the above embodiment has exemplified the case where the resource information for identifying the resource to be muted is stored. However, the mute indication may store, for example, information in the form of a bitmap so that the position of the resource to be muted in the selection window and whether or not each resource is reserved can be identified. Embodiment 7 will be described below.

FIG. 17 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the seventh embodiment. The mute indication divides the position of each resource in the selection window that fluctuates according to the maximum allowable delay time of packet transmission of the transmission request, and provides resource information in a bitmap format so that the position of the resource to be muted can be identified. Is stored. For example, when the allowable maximum delay time is 3 ms, the time width of the selected window is 3 ms. Therefore, the selection window can be partitioned into 3 × 3 nine resources. The resource information in the bitmap format is partitioned into nine resources, and for example, resources to be muted are represented by “1”, and resources other than resources to be muted are represented by “0”.

When the mobile station 2A of the UE 10 detects the transmission request of the high-priority packet transmission, the mobile station 2A of the UE 10 captures the usage status of the resources of the other mobile stations 2 based on the sensing result up to 1000 ms before detecting the transmission request. . The mobile station 2A of the UE 10 sets a selection window according to the allowable maximum delay time of transmission of a high-priority packet of a transmission request, and uses a free space to be used for transmission of a high-priority packet of a transmission request based on the usage status of other mobile stations 2. Determine whether resources are insufficient. The mobile station 2A of the UE 10 allocates a free resource to the transmission data of the transmission request when there is no shortage of the free resource used for transmitting the transmission request of the high-priority packet.

Also, when the free resources used for high-priority packet transmission are insufficient, the mobile station 2A of the UE 10 assigns a low-priority reserved resource lower than the priority level (high-priority) of the packet transmission of the transmission request. Select as a resource to be muted. At this time, the mobile station 2A of the UE 10 selects, for example, a resource reserved by the mobile station 2B of the UE 1 for low-priority packet transmission as a resource to be muted. The mobile station 2A of the UE 10 generates bitmap format resource information in which the position of the resource to be muted in the selection window is “1”, and the position of other resources other than the resource to be muted in the selection window is “0”. . Then, the mobile station 2A of the UE 10 generates a mute indication including the resource information in the bitmap format. Then, the mobile station 2A of the UE 10 broadcasts the mute indication to the other mobile stations 2 through the indication channel.

{Circle around (2)} Each mobile station 2B monitors the monitoring cycle of the indication channel, and determines whether or not the mute indication has been received according to the monitoring cycle. When receiving the mute indication, the mobile station 2B decodes the mute indication and specifies the resource position of the resource information in the mute indication. The mobile station 2B determines whether the specified resource location is the same as the resource location reserved by the mobile station 2B. The mobile station 2B of the UE 1 refers to the resource information in the bitmap format, and when the specified resource position is the same as the resource position reserved by the own station, the resource to be muted is the reserved resource of the own station. And release the reserved resource.

Then, the mobile station 2A of the UE 10 that has transmitted the mute indication allocates the high-priority packet transmission of the transmission request to the empty resource to be muted released by the mobile station 2B of the UE 1 according to the mute indication. As a result, the mobile station 2A of the UE 10 can execute high-priority packet transmission of the transmission request even when the available resources are insufficient.

Since the time width of the resource information in the bitmap format in the selection window varies according to the maximum permissible delay time of packet transmission, the division of the resource position in the bitmap format may also vary according to the time width. Needless to say.

In the seventh embodiment, the identification information that enables the resource position in the selection window and the reservation status of each resource to be identified in the bitmap format is transmitted by the mute indication. As a result, each mobile station 2 receiving the mute indication can easily identify the resource to be muted by referring to the resource information in the bitmap format.

In the above-described embodiment, the wireless communication system 1B of the V2V communication is illustrated, but the present invention is also applicable to, for example, V2X communication such as V2P communication and V2I communication.

The example in which the resource information of the first embodiment includes identification information for identifying the position of the resource to be muted. However, the mobile station identification information for identifying the mobile station 2 using the resource and the priority level of packet transmission used for the resource may be included, and can be changed as appropriate.

When detecting the transmission request of the high-priority packet, the member station 2D of the second embodiment selects the resource to be muted with the lower priority level of the high-priority packet from the sensing result up to 1000 msec from the detection of the transmission request. I do. Then, the case where the member station 2D transmits the selected resource to be muted to the head station 2C as a mute request has been exemplified, but the present invention is not limited to this. For example, when detecting the transmission request of the high-priority packet, the member station 2D transmits the mute request to the head station 2C without selecting the resource to be muted. Then, the head station 2C may select the resource to be muted in response to the mute request, and may broadcast the mute indication including the resource information of the resource to be muted to other mobile stations, and may change it appropriately. In this case, when transmitting the mute indication, the head station 2C notifies the member station 2D that transmitted the mute request of the resource to be muted.

In the fifth and sixth embodiments, the case where the head station 2C receives a mute request from the plurality of member stations 2D is exemplified as the case where there are a plurality of resources to be muted. However, the present invention is not limited to this, and is also applicable when a certain member station 2D detects a plurality of transmission requests.

FIG. 18 is an explanatory diagram showing an example of a mute sign transmission method and a mute operation according to the eighth embodiment. It is assumed that the mobile station 2A of the UE 10 has reserved V2V communication with a resource at a predetermined position (resource has been reserved).

When the mobile station 2A of the UE 10 determines that the resource reserved by the mobile station 2A is smaller than the size of the high-priority packet of the transmission request, it adds the information of the mute indication to the control information (SCI) area of the reserved resource. . In short, a part of the SCI for the data to be transmitted includes information for determining whether or not to execute the mute indication, or information on a mute indication indicating information on a muted target resource for which the mute indication is performed. After that, the other mobile station 2 detects the information of the SCI, decodes the information of the SCI, and decodes the information of the mute indication in the SCI. Further, the mobile station 2 decodes the information of the mute indication to determine whether or not there is information for releasing the resource to be muted. The other mobile station 2 determines whether the resource reserved by the own station is a resource to be muted. If the resource reserved by the mobile station 2 is a resource to be muted, the mobile station 2 releases the resource to be muted.

For example, when the mobile station 2A of the UE 10 detects a transmission request of a high-priority packet larger than the size of the resource reserved by the own station, the mobile station 2A based on the sensing result from the time when the transmission request was detected to 1000 ms before, The usage status of resources of another mobile station 2 is captured. The mobile station 2A sets a selection window according to the maximum permissible delay time of the transmission request, and determines whether or not there is insufficient free resources to be used for high-priority packet transmission of the transmission request based on the usage status of the other mobile stations 2. Is determined. The mobile station 2A of the UE 10 selects a reserved resource with a low priority as a resource to be muted when there is a shortage of free resources to be used for transmitting a high-priority packet for a transmission request. Then, the mobile station 2A adds the information of the mute indication including the resource information for identifying the selected resource to be muted to the SCI area in the reserved resource.

(4) The mobile station 2 decodes the information of the SCI in each resource, and decodes the information of the mute indication in the SCI. Further, the mobile station 2 decodes the information of the mute indication to determine whether or not there is information for releasing the resource to be muted. Among the other mobile stations 2, the mobile station 2B of the UE 2 determines whether or not the resource reserved by the own station is a resource to be muted. As illustrated in FIG. 18, the mobile station 2 </ b> B of the UE 2 releases the resource to be muted when the resource reserved in the own station is the resource to be muted.

Then, the mobile station 2A of the UE 10 allocates the high-priority packet transmission of the transmission request to the reserved resources and the free resources to be muted released by the mobile station 2B of the UE 2 according to the mute indication. As a result, the mobile station 2A of the UE 10 allocates the high-priority packet transmission to the released free resources in addition to the reserved resources.

The mobile station 2A according to the eighth embodiment, when the resources used for transmitting a high-priority packet for a transmission request are not enough resources reserved by the own station and the available resources are insufficient in the selection window. The information of the mute indication is added to the SCI area in the reserved resource of. Each mobile station 2 decodes the SCI of the frequency band of the V2V communication, and releases the resource to be muted when the resource to be muted is a resource reserved in the own station. As a result, the mobile station 2A transmits the high-priority packet even if the resources used for transmitting the high-priority packet are not enough resources reserved by the own station and the available resources are insufficient in the selection window. Can be realized.

Further, when there is a resource reserved by the own station, the mobile station 2 of the eighth embodiment does not reserve a dedicated resource to be used for the mute indication, and displays the mute indication in the SCI area within the resource reserved by the own station. Is added. As a result, even if there is no dedicated resource, the mute indication can be transmitted to each mobile station 2 using the SCI of the resource used by the own station, so that the radio efficiency of V2V communication can be improved.

FIG. 19 is an explanatory diagram showing an example of an SCI format including information on a mute sign. The SCI format shown in FIG. 19 includes, for example, a time difference (Time @ Gap: time interval) between an initial transmission (initial @ transmission) and a retransmission (retransmission), a retransmission index, and frequency resources of the initial transmission and the retransmission. It has a location and a resource reservation. The SCI format has, for example, a mute indication information bit, an MCS, a group destination ID, a priority information bit, and a retransmission index. The time difference between the initial transmission and the retransmission is 4 bits, the retransmission index is 1 bit, the frequency resource position between the initial transmission and the retransmission is 8 bits, and the resource reservation is 4 bits. The MCS has 5 bits, the group destination ID has 8 bits, the priority information bit has 3 bits, the retransmission index has 1 bit, and the mute indication information bit has 9 bits.

The mute indication information bit arranges resource information for identifying the position of the resource to be muted. As shown in FIG. 17, for example, when the resource arrangement in the selection window is partitioned into 3 × 3, the mute indication information bits represent the resource position to be muted in a bitmap format of “9” bits. For example, when the resource arrangement configuration in the selection window is partitioned into 2 × 2, the position of the resource to be muted is expressed in a bitmap format of “4” bits. Further, when the resource arrangement configuration in the selection window is partitioned into 4 × 4, the position of the resource to be muted is expressed in a “16” bit bitmap format. Therefore, the number of mute indication information bits is appropriately changed according to the resource arrangement configuration in the selection window.

Further, when there is a resource reserved in the mobile station 2, the mobile station 2 adds the information of the mute indication to the SCI in the resource reserved in the mobile station without securing a dedicated resource used for the mute indication. . As a result, even if there is no dedicated resource, the mute indication in the bitmap format can be transmitted to each mobile station 2 using the SCI of the resource used by the own station, so that the radio efficiency of V2V communication can be improved.

FIG. 20 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the ninth embodiment. In the subchannel of the eighth embodiment, the SCI area of the subchannel and the data area of the subchannel are in the same time area, whereas the subchannel of the ninth embodiment is different from the SCI area of the subchannel and the subchannel. The data area of the channel is in a different time domain. As shown in FIG. 20, the time domain of the sub-channel data area of the mobile station 2A of the UE 10 and the SCI domain of the sub-channel of the mobile station 2A of the UE 10 are different. It is assumed that the mobile station 2A of the UE 10 has reserved V2V communication with a resource at a predetermined position (resource has been reserved).

When the mobile station 2A of the UE 10 determines that the reserved resource is smaller than the size of the high-priority packet of the transmission request, the mobile station 2A adds the information of the mute indication to the SCI area of the reserved resource. The SCI area of the sub-channel corresponding to the reserved resource and the data area of the sub-channel are in different time areas.

The other mobile station 2 detects the information of the SCI and decodes the information of the SCI, and decodes the information of the mute sign in the SCI. Further, the mobile station 2 decodes the information of the mute indication to determine whether or not there is information for releasing the resource to be muted. The other mobile station 2 determines whether the resource reserved by the own station is a resource to be muted. If the resource reserved by the mobile station 2 is a resource to be muted, the mobile station 2 releases the resource to be muted.

For example, when the mobile station 2A of the UE 10 detects a transmission request of a high-priority packet larger than the size of the resource reserved by the own station, the mobile station 2A based on the sensing result from the time when the transmission request was detected to 1000 ms before, The usage status of resources of another mobile station 2 is captured. The mobile station 2A sets a selection window according to the maximum permissible delay time of the transmission request, and determines whether or not there is a shortage of available resources to be used for transmitting a high-priority packet of the transmission request based on the usage status of the other mobile stations 2. Is determined. The mobile station 2A of the UE 10 selects a reserved resource with a low priority as a resource to be muted when there is a shortage of free resources to be used for transmitting a high-priority packet for a transmission request. Then, the mobile station 2A adds the information of the mute indication including the resource information for identifying the selected resource to be muted to the SCI area in the time area different from the data area of the reserved resource.

(4) The mobile station 2 decodes the information of the SCI in each resource, and decodes the information of the mute indication in the SCI. Further, the mobile station 2 decodes the information of the mute indication to determine whether or not there is information for releasing the resource to be muted. Among the other mobile stations 2, the mobile station 2B of the UE 2 determines whether or not the resource reserved by the own station is a resource to be muted. As shown in FIG. 20, when the resource reserved in the own station is the resource to be muted, the mobile station 2B of the UE 2 releases the resource to be muted.

The mobile station 2A according to the ninth embodiment, when the resources used for transmitting a high-priority packet for a transmission request are not enough resources reserved by the own station and the available resources are insufficient in the selection window, Adds the information of the mute indication to the SCI area in the reserved resource. Each mobile station 2 decodes the SCI of the frequency band of the V2V communication, and releases the resource to be muted when the resource to be muted is a resource reserved in the own station. As a result, the mobile station 2A can transmit the high-priority packet even if the resources used for transmitting the high-priority packet are not enough resources reserved by the own station and the available resources are insufficient in the selection window. Can be realized.

Further, when there is a resource reserved by the own station, the mobile station 2 according to the ninth embodiment does not secure a dedicated resource used for the mute indication, and the data area and the time area within the resource reserved by the own station. Add mute sign information to different SCI areas. As a result, even if there is no dedicated resource, the mute indication can be transmitted to each mobile station 2 using the SCI of the resource used by the own station, so that the radio efficiency of V2V communication can be improved.

Note that the mobile station 2 of the UE 10 may specify the resource to be muted based on the time domain or the frequency-time domain of the reserved resource, or may specify the resource to be muted based on the time domain to which the information of the mute indication is added. The resource may be specified and can be changed as appropriate.

FIG. 21 is an explanatory diagram illustrating an example of a mute sign transmission method and a mute operation according to the tenth embodiment. The mobile station 2 of the UE 10 secures resources for V2V communication resources according to the eighth embodiment in advance, and adds a mute indication to the SCI area in the same time area. On the other hand, for the resources of the V2V communication of the tenth embodiment, the information of the mute indication is added to the SCI area instead of the mobile station 2 of the UE 10 securing the resources in advance.

The resources of the three sub-channels in the same time domain illustrated in FIG. 21 include, for example, a resource of a frequency band in which three data regions are combined and a resource of a frequency band in which, for example, three SCI regions are combined. .

For example, when detecting the transmission request of the high-priority packet, the mobile station 2A of the UE 10 captures the usage status of the resources of the other mobile stations 2 based on the sensing result from the time when the transmission request was detected to 1000 ms before. . The mobile station 2A sets a selection window according to the maximum permissible delay time of the transmission request, and determines whether or not there is insufficient free resources to be used for high-priority packet transmission of the transmission request based on the usage status of the other mobile stations 2. Is determined. The mobile station 2A of the UE 10 selects a reserved resource with a low priority as a resource to be muted when there is a shortage of free resources to be used for transmitting a high-priority packet for a transmission request. In the example shown in FIG. 21, two resources are selected as resources to be used for a high-priority packet of a transmission request. Then, the mobile station 2A of the UE 10 adds the information of the mute indication including the resource information for identifying the selected resource to be muted to the SCI area.

(4) The mobile station 2 decodes the information of the SCI in each resource, and decodes the information of the mute indication in the SCI. Further, the mobile station 2 decodes the information of the mute indication to determine whether or not there is information for releasing the resource to be muted. Among the other mobile stations 2, the mobile stations 2B of the UE1 and the UE2 determine whether or not the resource reserved by the own station is a resource to be muted. As shown in FIG. 20, when the resource reserved in the own station is a resource to be muted, the mobile station 2B of the UE 1 releases the resource to be muted. Similarly, the mobile station 2B of the UE2 releases the resource to be muted when the resource reserved in the own station is the resource to be muted as shown in FIG.

Then, the mobile station 2A of the UE 10 allocates the high-priority packet transmission of the transmission request to the free resources to be muted released by the mobile stations 2B of the UE1 and the UE2 according to the mute indication. As a result, the mobile station 2A of the UE 10 allocates high-priority packet transmission to the released free resources.

The mobile station 2A according to the tenth embodiment adds the information of the mute indication to the SCI when the available resources used for transmitting the transmission request high-priority packet are insufficient. Each mobile station 2 decodes the SCI of the frequency band of the V2V communication, and releases the reserved resource to be muted when the resource to be muted is a resource reserved by the own station. As a result, the mobile station 2A can realize high-priority packet transmission even when there are insufficient free resources used for high-priority packet transmission.

Further, the mobile station 2 according to the tenth embodiment adds the information of the mute indication to the SCI area without securing the dedicated resource used for the mute indication. As a result, the mute indication can be transmitted to each mobile station 2 using the SCI even without a dedicated resource, so that the radio efficiency of V2V communication can be improved.

Although the resources of the V2 communication according to the tenth embodiment have exemplified the resource configuration having the frequency band in which the SCI area is combined and the frequency band in which the data area is combined in the same time domain, the present invention is not limited to this. For example, the resource configuration shown in FIG. 18 or the resource configuration shown in FIG. 20 may be used, and the mobile station 2A may add a mute indication to one SCI area in the resource, and can change it as appropriate.

Note that the mute indication in the SCI area shown in FIG. 21 specifies the initial position of the resource, and specifies the resource to be muted by indicating a frequency domain or a time domain that is continuous from the initial position. Further, a plurality of resources to be muted may be indicated by the information of the mute indication. In this case, for example, a plurality of resources to be muted having a value indicating “1” out of 9 bits is easily released. The resources to be muted can be released.

As described above, in the eighth to tenth embodiments, the mute sign can be instructed by using the SCI. Therefore, it is possible to cope with the case where the packet size of the transmission request is larger than the resource for which the size is secured. It should be noted that Examples 8 to 10 and Examples 1 to 7 can be used in combination. For example, the first mute target resource is indicated to each mobile station 2 by the mute indication described in the first embodiment. Further, using the SCI described in the eighth to tenth embodiments, a necessary resource may be transmitted to each mobile station 2 as a resource to be muted based on the first resource position to be muted, and may be appropriately changed. is there.

1B

Wireless communication system

2, 2A, 2B Mobile station

2C Head station

2D Member station

2E Member station 41 Judgment unit 42 Generation unit 43 Transmission unit 44 Assignment unit 45 Opening unit

Claims

When detecting a high-priority data transmission request for directly communicating with another terminal device, it is determined whether there is insufficient resource to be allocated to data transmission of the transmission request among a plurality of resources that can be allocated to data transmission. A determining unit for determining,
When there are insufficient resources to be allocated to the data transmission of the transmission request, the other terminal device used for data transmission lower than the priority level of the data transmission of the transmission request selects a reserved resource, and selects A generation unit that generates a command requesting release of the reserved resource that has been
A transmission unit that transmits the command generated by the generation unit to each of the other terminal devices,
A allocating unit that allocates resources released by the other terminal device in response to the command to data transmission of the transmission request.
The apparatus according to claim 1, further comprising: an opening unit that releases the reserved resource when the resource requested to be released by the command received from the other terminal device is a resource reserved by the own device. Terminal device.
The transmission unit,
The terminal device according to claim 1, wherein the command is transmitted to each of the other terminal devices using a resource of a predetermined cycle in the plurality of resources.
4. The command according to claim 3, wherein the command is arranged in control information in a sub-channel of the resource, and has identification information for identifying the command so that the command can be identified from control information used for data transmission. Terminal device.
The plurality of resources has a data area for storing data, and a control information area for storing control information,
The transmission unit,
The terminal device according to claim 1, wherein the command is transmitted to each of the other terminal devices using the control information area.
The transmission unit,
The terminal device according to claim 1, wherein the command is transmitted to each of the other terminal devices by using resources of a predetermined cycle in a frequency band different from the plurality of resources.
The command is
The terminal device according to claim 1, further comprising resource information for identifying a resource for which release is requested.
The command is
The terminal device according to claim 1, wherein the terminal device includes resource information in which a position of each resource in a selection window used for the data transmission and whether or not each resource is to be released can be identified in a bitmap format.
The command is
2. A method according to claim 1, wherein a plurality of resources in the selection window used for the data transmission are partitioned, and resource information in a bitmap format in which the presence or absence of a release target can be identified in a bit format for each partitioned resource is included. A terminal device according to item 1.
When detecting a transmission request for data that directly communicates with another terminal device, an allocating unit that allocates data transmission of the transmission request among a plurality of resources that can be allocated for data transmission,
If the own device receives a command requesting release of a reserved resource from the other terminal device, and the command requesting release is a resource reserved by the own device, the reserved resource A terminal device, comprising: an opening unit that opens the terminal.
A wireless communication system having a first terminal device and a second terminal device that directly communicates with the first terminal device,
The first terminal device includes:
When detecting a transmission request of high-priority data, a determination unit that determines whether there are insufficient resources to be allocated to data transmission of the transmission request among a plurality of resources that can be allocated to data transmission,
When there are insufficient resources to be allocated to the data transmission of the transmission request, another terminal device used for data transmission lower than the priority level of the data transmission of the transmission request selects a reserved resource and selects A generation unit that generates a command requesting release of reserved resources;
A transmitting unit that transmits the command generated by the generating unit to each of the other terminal devices,
The second terminal device includes:
An opening unit that releases the reserved resource when the resource requested to be released by the command received from the first terminal device is a resource reserved by the own device,
The first terminal device includes:
A wireless communication system, comprising: an assignment unit that assigns resources released by the second terminal device to data transmission of the transmission request after transmitting the command.
A wireless terminal comprising: a first terminal device; a second terminal device that directly communicates with the first terminal device; and a third terminal device that directly communicates with the first terminal device and the second terminal device. A communication system,
The first terminal device includes:
When detecting a transmission request of high-priority data, a determination unit that determines whether there are insufficient resources to be allocated to data transmission of the transmission request among a plurality of resources that can be allocated to data transmission,
When there are insufficient resources to be allocated to the data transmission of the transmission request, another terminal device used for data transmission lower than the priority level of the data transmission of the transmission request selects a reserved resource and selects A transmission unit that generates a request for requesting release of reserved resources, and transmits the generated request to the second terminal device;
The second terminal device includes:
A generating unit that, when receiving the request from the first terminal device, generates a command requesting release of resources related to the request;
A transmission unit that transmits the command generated by the generation unit to each of the other terminal devices,
The third terminal device includes:
The resource received by the command from the second terminal device has a release unit that releases the reserved resource when the resource requesting release is a resource reserved by the own device,
The first terminal device includes:
A wireless communication system, comprising: an allocating unit that allocates resources released by the third terminal device to data transmission of the transmission request after transmitting the command.