Transmitting station, transmitting method, and transmitting program

Abstract

This transmitter station comprises: a first transmission unit; a second transmission unit; and a management unit. The management unit establishes, with a receiver station, a multilink in which a first channel is assigned to the first transmission unit and a second channel is assigned to the second transmission unit, and assigns a service period to the first channel. In a case where a first occupancy period for transmitting first data and padding overlaps the service period, the first transmission unit is configured to postpone transmission of the first data and the padding in line with transmission of second data by the second transmission unit.

Description

[Technical Field]

[0001] The embodiments relate to a transmitting station, a transmitting method, and a transmitting program. [Background technology]

[0002] Wireless LANs (Local Area Networks) are known as systems that wirelessly connect access points and terminals. Wireless LANs allow terminals located within the communication range of an access point to access a network via the access point. Access points and terminals may establish service periods to prioritize the exchange of low-latency traffic. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] IEEE P802.11beTM / D1.5, “35.9 Restricted TWT (r-TWT)”, March 18, 2022 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to exchange low latency traffic preferentially, it is desirable to control transmission so that the exchange period of other traffic does not overlap with the service period.

[0005] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a wireless communication environment in which low latency traffic can be exchanged preferentially. [Means for solving the problem]

[0006] A transmitting station according to one aspect includes a first transmitting unit, a second transmitting unit, and a management unit. The management unit establishes a multilink with a receiving station, which assigns a first channel to the first transmitting unit and a second channel to the second transmitting unit, and assigns a service period to the first channel. When a first occupation period for transmitting first data and padding overlaps with the service period, the first transmitting unit assigns a service period to the second transmitting unit. but Second Data Second occupancy period for sending In accordance with hand The first data and the padding of send To do configured to postpone the The service period is a period during which data with lower latency than the first data is exchanged preferentially. [Effects of the Invention]

[0007] According to the embodiment, it is possible to provide a wireless communication environment in which low latency traffic can be exchanged preferentially. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing the configuration of a communication system according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of link management information of the communication system according to the embodiment. [Figure 3] FIG. 3 is a block diagram illustrating an example of a hardware configuration of an access point according to the embodiment. [Figure 4] FIG. 4 is a block diagram illustrating an example of a hardware configuration of a terminal according to the embodiment. [Figure 5] FIG. 5 is a block diagram illustrating an example of a functional configuration of an access point according to the embodiment. [Figure 6] FIG. 6 is a diagram illustrating an example of a format of a beacon frame according to the embodiment. [Figure 7] FIG. 7 is a block diagram illustrating an example of a functional configuration of a terminal according to the embodiment. [Figure 8] FIG. 8 is a block diagram illustrating an example of a functional configuration related to the transmission determination process of the terminal according to the embodiment. [Figure 9] FIG. 9 is a flowchart illustrating an example of a transmission determination process in the radio signal processing unit of the terminal according to the embodiment. [Figure 10] FIG. 10 is a flowchart illustrating an example of a transmission determination process in the transmission timing adjustment unit of the terminal according to the embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of a transmission determination process in the transmitting station according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. In the following description, components having the same functions and configurations will be given the same reference numerals.

[0010] (Embodiment) 1. Configuration The configuration of a communication system according to an embodiment will be described.

[0011] 1.1 Communication Systems FIG. 1 is a block diagram showing an example of the configuration of a communication system according to an embodiment.

[0012] As shown in FIG. 1, the communication system 1 includes an access point 10, a terminal 20, and a network 30.

[0013] The access point 10 is, for example, a base station of a wireless LAN. The access point 10 is configured to communicate with a server (not shown) on the network 30 via wired or wireless communication. The access point 10 is configured to communicate with the terminal 20 via wireless communication. The communication between the access point 10 and the terminal 20 complies with, for example, the IEEE 802.11 standard.

[0014] The terminal 20 is, for example, a wireless terminal such as a smartphone or a PC (Personal Computer), etc. The terminal 20 is configured to communicate with a server on the network 30 via the access point 10.

[0015] The access point 10 and the terminal 20 have wireless communication functions based on, for example, the OSI (Open Systems Interconnection) reference model. In the OSI reference model, wireless communication functions are divided into seven layers (layer 1: physical layer, layer 2: data link layer, layer 3: network layer, layer 4: transport layer, layer 5: session layer, layer 6: presentation layer, and layer 7: application layer). The data link layer includes a Logical Link Control (LLC) sublayer and a Media Access Control (MAC) sublayer.

[0016] Multilink ML can be applied as a wireless connection method between the access point 10 and the terminal 20. Multilink ML is a wireless connection method that can transmit and receive data (exchange traffic) using multiple links simultaneously. The access point 10 and the terminal 20 to which Multilink ML is applied manage the state of Multilink ML using link management information.

[0017] 2 is a diagram illustrating an example of link management information of the communication system according to the embodiment. The link management information includes, for example, information on a "link ID," a "link," a "frequency band," a "channel ID," a "multi-link," and a "traffic."

[0018] A "link ID" is an identifier associated with an STA function. The STA function is a functional configuration that each of the access point 10 and the terminal 20 has in order to establish a link between the access point 10 and the terminal 20. That is, one pair of STA functions is used to establish one link. The example of FIG. 2 shows a case where three pairs of STA functions (STA1, STA2, and STA3) are assigned to wireless communication between the access point 10 and the terminal 20. The STA functions correspond to a wireless signal processing unit, which will be described later.

[0019] "Link" is information indicating whether or not a link has been established between the access point 10 and the terminal 20 by the STA function. The example of Fig. 2 shows a case where all of STA1, STA2, and STA3 have established links between the access point 10 and the terminal 20.

[0020] "Frequency band" is information indicating the frequency band used for the link. The applicable frequency bands include, for example, the 6 GHz band, the 5 GHz band, and the 2.4 GHz band. Each frequency band includes multiple channels. The example in FIG. 2 shows a case where the 5 GHz band is assigned to all of STA1, STA2, and STA3.

[0021] "Channel ID" is an identifier of the channel used for the link. In the example of Figure 2, STA1, STA2, and STA3 are respectively assigned channels CH1, CH2, and CH3 in the 5 GHz band. For example, channels CH1, CH2, and CH3 may be assigned frequency bands that are close enough to each other that power leakage occurs.

[0022] "Multilink" is information indicating whether or not a multilink ML has been established between the access point 10 and the terminal 20. In the example of Fig. 2, a case is shown in which a set of STA1, STA2, and STA3 has established a multilink ML.

[0023] "Traffic" is information indicating a TID (Traffic Indicator) assigned to an STA function. A TID is an identifier indicating each type of traffic, and may be associated with an access category. Access categories of traffic include, for example, "VO (Voice)," "VI (Video)," "BE (Best Effort)," "BK (Background)," and "LL (Low Latency)." Access category LL is traffic that requires low delay (low latency). Each of TIDs #1 to #4 in FIG. 2 corresponds to, for example, one of the access categories VO, VI, BE, BK, and LL. The example in FIG. 2 shows a case where TID #1 is assigned to STA1, STA2, and STA3. Also shown is a case where TIDs #2, #3, and #4 are further assigned to STA1, STA2, and STA3, respectively.

[0024] In this way, in a multilink ML, one or more STA functions can be assigned to one TID. The association between traffic and STA functions is set, for example, so that the traffic volume is equalized among the multiple links constituting the multilink ML. Note that the association between traffic and STA functions is not limited to the above example, and for example, similar types of traffic, such as traffic requiring low latency and traffic not requiring low latency, may be collected in specific links constituting the multilink ML.

[0025] The access point 10 and the terminal 20 have an rTWT (restricted Target Wake Time) function to ensure an opportunity to exchange traffic requiring low latency in the above-mentioned multilink ML. By using the rTWT function, the access point 10 and the terminal 20 can set a service period in which the exchange of traffic requiring low latency can be prioritized over the exchange of traffic not requiring low latency. Such a service period is also called an rTWT-SP (Service Period).

[0026] 1.2 Hardware Configuration Next, the hardware configuration of the access point and the terminal in the communication system according to the embodiment will be described.

[0027] 1.2.1 Access point hardware configuration FIG. 3 is a block diagram illustrating an example of a hardware configuration of an access point according to the embodiment.

[0028] As shown in FIG. 3, the access point 10 includes, for example, a central processing unit (CPU) 11, a read only memory (ROM) 12, a random access memory (RAM) 13, a wireless communication module 14, and a wired communication module 15.

[0029] The CPU 11 is a processing circuit that controls the overall operation of the access point 10. The ROM 12 is, for example, a non-volatile semiconductor memory. The ROM 12 stores programs and data for controlling the access point 10. The RAM 13 is, for example, a volatile semiconductor memory. The RAM 13 is used as a working area for the CPU 11. The wireless communication module 14 is a circuit used to send and receive data by wireless signals. The wireless communication module 14 is connected to an antenna. The wired communication module 15 is a circuit used to send and receive data by wired signals. The wired communication module 15 is connected to the network 30.

[0030] 1.2.2 Terminal hardware configuration FIG. 4 is a block diagram illustrating an example of a hardware configuration of a terminal according to the embodiment.

[0031] As shown in FIG. 4, the terminal 20 includes, for example, a CPU 21, a ROM 22, a RAM 23, a wireless communication module 24, a display 25, and a storage 26.

[0032] The CPU 21 is a processing circuit that controls the overall operation of the terminal 20. The ROM 22 is, for example, a non-volatile semiconductor memory. The ROM 22 stores programs and data for controlling the terminal 20. The RAM 23 is, for example, a volatile semiconductor memory. The RAM 23 is used as a working area for the CPU 21. The wireless communication module 24 is a circuit used for transmitting and receiving data via wireless signals. The wireless communication module 24 is connected to an antenna. The display 25 is, for example, an LCD (Liquid Crystal Display) or an EL (Electro-Luminescence) display. The display 25 displays a GUI (Graphical User Interface) corresponding to application software, etc. The storage 26 is a non-volatile storage device. The storage 26 stores system software, etc. of the terminal 20.

[0033] 1.3 Functional Configuration Next, the functional configuration of the access point and the terminal in the communication system according to the embodiment will be described.

[0034] 1.3.1 Access point functional configuration FIG. 5 is a block diagram illustrating an example of a functional configuration of an access point according to the embodiment.

[0035] The access point 10 functions as a computer including an LLC processing unit 110, a data processing unit 120, a management unit 130, a MAC frame processing unit 140, multiple radio signal processing units 150, 160, and 170, and a transmission timing adjustment unit 180. The LLC processing unit 110 is a functional block that executes processing corresponding to the LLC sublayer of the second layer and layers 3 to 7. The data processing unit 120, the management unit 130, and the MAC frame processing unit 140 are functional blocks that execute processing corresponding to the MAC sublayer of the second layer. The multiple radio signal processing units 150, 160, and 170, and the transmission timing adjustment unit 180 are functional blocks that execute processing corresponding to the MAC sublayer of the second layer and layer 1.

[0036] The LLC processing unit 110 generates LLC packets by, for example, adding a DSAP (Destination Service Access Point) header, an SSAP (Source Service Access Point) header, etc. to data received from the network 30. The LLC processing unit 110 then inputs the generated LLC packets to the data processing unit 120. The LLC processing unit 110 also extracts data from the LLC packets input from the data processing unit 120. The LLC processing unit 110 then transmits the extracted data to the network 30.

[0037] The data processing unit 120 generates a MAC frame by adding a MAC header to the LLC packet input from the LLC processing unit 110. The data processing unit 120 then inputs the generated MAC frame to the MAC frame processing unit 140. The data processing unit 120 also extracts the LLC packet from the MAC frame input from the MAC frame processing unit 140. The data processing unit 120 then inputs the extracted LLC packet to the LLC processing unit 110. Hereinafter, a MAC frame containing data will also be referred to as a "data frame."

[0038] The management unit 130 manages the state of the link between the access point 10 and the terminal 20. MAC frames including management information related to the link, rTWT, etc. are input and output between the management unit 130 and the MAC frame processing unit 140. Hereinafter, MAC frames including management information are also referred to as "management frames." The management unit 130 includes link management information 131, a link management unit 132, and a beacon management unit 133.

[0039] The link management information 131 is information relating to the link between the access point 10 and the wirelessly connected terminal 20. The link management information 131 includes, for example, the information shown in FIG.

[0040] The link management unit 132 controls the establishment of a link with the terminal 20. For example, the link management unit 132 executes association processing and subsequent authentication processing in response to a connection request from the terminal 20. The link management unit 132 controls the state of the link established with the terminal 20. For example, the link management unit 132 can determine the association between a TID and an STA function when establishing a multilink ML.

[0041] The beacon management unit 133 manages information transmitted by the access point 10 as a beacon signal. Specifically, the beacon management unit 133 generates a management frame including management information related to the rTWT function. The beacon management unit 133 then inputs the generated management frame to the MAC frame processing unit 140. Hereinafter, the management frame generated by the beacon management unit 133 will also be referred to as a "beacon frame."

[0042] 6 is a diagram illustrating an example of a format of a beacon frame according to an embodiment. As illustrated in FIG. 6, the beacon frame includes, for example, an rTWT-SP start time Ts and an rTWT-SP duration D as management information used in the rTWT function.

[0043] The rTWT-SP start time Ts is information indicating the time when the service period rTWT-SP starts. The rTWT-SP duration D is information indicating the length of the service period rTWT-SP. In other words, the service period rTWT-SP is set as the period from the rTWT-SP start time Ts to the time when the rTWT-SP duration D has elapsed. The rTWT-SP start time Ts and the rTWT-SP duration D are set for each link. The rTWT-SP start time Ts and the rTWT-SP duration D set for each link are managed by the beacon management unit 133.

[0044] Returning to FIG. 5, the functional configuration of the access point 10 will be described.

[0045] When a MAC frame is input from the data processing unit 120 or the management unit 130, the MAC frame processing unit 140 associates the MAC frame with a link. For example, when a MAC frame is input from the data processing unit 120, the MAC frame processing unit 140 identifies the link associated with the TID included in the MAC header by referring to the link management information 131. The MAC frame processing unit 140 then inputs the MAC frame to the radio signal processing unit corresponding to the identified link. Furthermore, when a MAC frame is input from multiple radio signal processing units 150, 160, and 170, the MAC frame processing unit 140 inputs the MAC frame to the data processing unit 120 or the management unit 130 depending on the type of MAC frame. Specifically, if the MAC frame is a data frame, the MAC frame processing unit 140 inputs the MAC frame to the data processing unit 120. If the MAC frame is a management frame, the MAC frame processing unit 140 inputs the MAC frame to the management unit 130.

[0046] The multiple radio signal processing units 150, 160, and 170 correspond to STA1, STA2, and STA3 in the multilink ML shown in FIG. 2, respectively. The multiple radio signal processing units 150, 160, and 170 have the same functional configuration. Each of the multiple radio signal processing units 150, 160, and 170 generates a radio frame by adding a preamble or the like to the MAC frame input from the MAC frame processing unit 140. Each of the multiple radio signal processing units 150, 160, and 170 converts the generated radio frame into a radio signal. Then, each of the multiple radio signal processing units 150, 160, and 170 radiates (transmits) the converted radio signal via an antenna. The conversion process from the radio frame to the radio signal includes, for example, convolutional coding, interleaving, subcarrier modulation, inverse fast Fourier transform, Orthogonal Frequency Division Multiplexing (OFDM) modulation, and frequency conversion. Each of the multiple radio signal processing units 150, 160, and 170 converts a radio signal received from terminal 20 via an antenna into a radio frame. The conversion process from a radio signal to a radio frame includes, for example, frequency conversion, OFDM demodulation, fast Fourier transform, subcarrier demodulation, deinterleaving, and Viterbi decoding. Each of the multiple radio signal processing units 150, 160, and 170 extracts a MAC frame from the converted radio frame. Then, each of the multiple radio signal processing units 150, 160, and 170 inputs the extracted MAC frame to the MAC frame processing unit 140.

[0047] Prior to generating a radio frame, the multiple radio signal processing units 150, 160, and 170 execute a transmission determination process in cooperation with the transmission timing adjustment unit 180. The transmission determination process is a process for determining whether or not to transmit a data frame. The transmission determination process includes a carrier sense process. The carrier sense process is a process for determining the state of a channel used in a link. The transmission determination process will be described in detail later.

[0048] The transmission timing adjustment unit 180 is configured to function when the access point 10 operates as a transmitting station. In other words, when the access point 10 operates as a receiving station, the transmission timing adjustment unit 180 may be omitted. The transmission timing adjustment unit 180 manages the status related to the carrier sense processing in each of the multiple radio signal processing units 150, 160, and 170. Then, the transmission timing adjustment unit 180 adjusts the transmission timing of the data frame by each of the multiple radio signal processing units 150, 160, and 170 based on the status.

[0049] 1.3.2 Terminal Functional Configuration FIG. 7 is a block diagram illustrating an example of a functional configuration of a terminal according to the embodiment.

[0050] The terminal 20 functions as a computer including an application execution unit 200, an LLC processing unit 210, a data processing unit 220, a management unit 230, a MAC frame processing unit 240, multiple radio signal processing units 250, 260, and 270, and a transmission timing adjustment unit 280. The application execution unit 200 is a functional block that executes processing corresponding to layer 7. The LLC processing unit 210 is a functional block that executes processing corresponding to the LLC sublayer of layer 2 and layers 3 to 6. The data processing unit 220, the management unit 230, and the MAC frame processing unit 240 are functional blocks that execute processing corresponding to the MAC sublayer of layer 2. The multiple radio signal processing units 250, 260, and 270, and the transmission timing adjustment unit 280 are functional blocks that execute processing corresponding to the MAC sublayer of layer 2 and layer 1.

[0051] The application execution unit 200 executes an application based on data input from the LLC processing unit 210. The application execution unit 200 also inputs data to the LLC processing unit 210. For example, the application execution unit 200 can display application information on the display 25. The application execution unit 200 can also operate based on operations on an input interface.

[0052] The LLC processing unit 210 generates an LLC packet by adding a DSAP header, an SSAP header, etc. to the data from the application execution unit 200. Then, the LLC processing unit 210 inputs the generated LLC packet to the data processing unit 220. The LLC processing unit 210 also extracts data from the LLC packet input from the data processing unit 220. Then, the LLC processing unit 210 inputs the extracted data to the application execution unit 200.

[0053] The data processing unit 220 generates a MAC frame by adding a MAC header to the LLC packet input from the LLC processing unit 210. The data processing unit 220 then inputs the generated MAC frame to the MAC frame processing unit 240. The data processing unit 220 also extracts an LLC packet from the MAC frame input from the MAC frame processing unit 240. The data processing unit 220 then inputs the extracted LLC packet to the LLC processing unit 210.

[0054] The management unit 230 manages the state of the link between the access point 10 and the terminal 20. MAC frames including management information related to the link, rTWT, etc. are input and output between the management unit 230 and the MAC frame processing unit 240. The management unit 230 includes link management information 231, a link management unit 232, and a beacon management unit 233.

[0055] The link management information 231 is information relating to the link between the terminal 20 and the wirelessly connected access point 10. The link management information 231 includes, for example, the information shown in FIG.

[0056] The link management unit 232 controls the establishment of a link with the access point 10. For example, the link management unit 232 executes an association process and a subsequent authentication process when transmitting a connection request to the access point 10. The link management unit 232 controls the state of the link established with the access point 10. For example, the link management unit 232 can determine the association between a TID and an STA function when establishing a multilink ML.

[0057] The beacon management unit 233 manages information included in the beacon signal received from the access point 10. Specifically, the beacon management unit 233 extracts management information related to the rTWT function from the beacon frame input from the MAC frame processing unit 240. Then, the beacon management unit 233 manages, for example, the rTWT-SP start time Ts and the rTWT-SP duration D from the extracted management information related to the rTWT function for each link.

[0058] When a MAC frame is input from the data processing unit 220 or the management unit 230, the MAC frame processing unit 240 associates the MAC frame with a link. For example, when a MAC frame is input from the data processing unit 220, the MAC frame processing unit 240 identifies the link associated with the TID included in the MAC header by referring to the link management information 231. The MAC frame processing unit 240 then inputs the MAC frame to the radio signal processing unit corresponding to the identified link. Furthermore, when a MAC frame is input from multiple radio signal processing units 250, 260, and 270, the MAC frame processing unit 240 inputs the MAC frame to the data processing unit 220 or the management unit 230 depending on the type of MAC frame. Specifically, if the MAC frame is a data frame, the MAC frame processing unit 240 inputs the MAC frame to the data processing unit 220. If the MAC frame is a management frame, the MAC frame processing unit 240 inputs the MAC frame to the management unit 230.

[0059] The multiple radio signal processing units 250, 260, and 270 correspond to STA1, STA2, and STA3 in the multilink ML shown in FIG. 2, respectively. The multiple radio signal processing units 250, 260, and 270 have the same functional configuration. Each of the multiple radio signal processing units 250, 260, and 270 generates a radio frame by adding a preamble or the like to the MAC frame input from the MAC frame processing unit 240. Each of the multiple radio signal processing units 250, 260, and 270 converts the generated radio frame into a radio signal. Then, each of the multiple radio signal processing units 250, 260, and 270 radiates (transmits) the converted radio signal via an antenna. The conversion process from the radio frame to the radio signal includes, for example, convolutional coding, interleaving, subcarrier modulation, inverse fast Fourier transform, OFDM modulation, and frequency conversion. Each of the multiple radio signal processing units 250, 260, and 270 converts a radio signal received from the access point 10 via an antenna into a radio frame. The conversion process from the radio signal to the radio frame includes, for example, frequency conversion, OFDM demodulation, fast Fourier transform, subcarrier demodulation, deinterleaving, and Viterbi decoding. Each of the multiple radio signal processing units 250, 260, and 270 extracts a MAC frame from the converted radio frame. Then, each of the multiple radio signal processing units 250, 260, and 270 inputs the extracted MAC frame to the MAC frame processing unit 240.

[0060] Prior to generating a wireless frame, the multiple wireless signal processing units 250, 260, and 270 execute a transmission determination process in cooperation with the transmission timing adjustment unit 280. The transmission determination process in the terminal 20 is the same as the transmission determination process in the access point 10.

[0061] The transmission timing adjustment unit 280 is configured to function when the terminal 20 operates as a transmitting station. In other words, when the terminal 20 operates as a receiving station, the transmission timing adjustment unit 280 may be omitted. The transmission timing adjustment unit 280 manages the status related to the carrier sense processing in each of the multiple radio signal processing units 250, 260, and 270. Then, the transmission timing adjustment unit 280 adjusts the transmission timing of the radio signal by each of the multiple radio signal processing units 250, 260, and 270 based on the status.

[0062] 1.3.3 Functional configuration related to transmission decision processing Next, a functional configuration related to the transmission determination process of each of the access point 10 and the terminal 20 according to the embodiment will be described. When executing the transmission determination process, each of the access point 10 and the terminal 20 functions as a transmitting station. Specifically, when the access point 10 executes the transmission determination process, each of the radio signal processing units 150, 160, and 170 functions as a transmitting unit that operates in cooperation with the transmission timing adjustment unit 180. When the terminal 20 executes the transmission determination process, each of the radio signal processing units 250, 260, and 270 functions as a transmitting unit that operates in cooperation with the transmission timing adjustment unit 280. Below, a functional configuration related to the transmission determination process of the terminal 20 will be described as an example.

[0063] Fig. 8 is a block diagram showing an example of a functional configuration related to transmission determination processing of a terminal according to an embodiment. The example of Fig. 8 shows a beacon management unit 233, a wireless signal processing unit 250, and a transmission timing adjustment unit 280. Note that the functional configurations related to the transmission determination processing of each of the wireless signal processing units 260 and 270 are the same as the functional configuration related to the transmission determination processing of the wireless signal processing unit 250, and therefore descriptions thereof will be omitted.

[0064] The radio signal processing unit 250 includes a classification unit 251, a plurality of queues 252A, 252B, 252C, and 252D, a plurality of carrier sense units 253A, 253B, 253C, and 253D, and an internal collision management unit 254.

[0065] When the MAC frame input from MAC frame processing unit 240 is a data frame, classification unit 251 classifies the data frame into a plurality of access categories based on the TID included in the MAC header. Then, classification unit 251 inputs the data frame to a corresponding queue 252 out of a plurality of queues 252A, 252B, 252C, and 252D. In the example of Fig. 8, classification unit 251 inputs data frames corresponding to access categories VO, VI, BE, and BK to queues 252A, 252B, 252C, and 252D, respectively.

[0066] Each of the multiple queues 252A, 252B, 252C, and 252D buffers input data frames. In the example of Figure 8, the multiple queues 252A, 252B, 252C, and 252D buffer data frames corresponding to the access categories VO, VI, BE, and BK, respectively.

[0067] The plurality of carrier sense units 253A, 253B, 253C, and 253D correspond to the plurality of queues 252A, 252B, 252C, and 252D, respectively. Each of the plurality of carrier sense units 253A, 253B, 253C, and 253D performs carrier sense processing based on CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) in accordance with preset access parameters. If it is determined that the channel is in an idle state for a predetermined time, each of the plurality of carrier sense units 253A, 253B, 253C, and 253D acquires the right to transmit a data frame and terminates the carrier sense processing. If it is determined that the channel is in a busy state, each of the plurality of carrier sense units 253A, 253B, 253C, and 253D stops acquiring the right to transmit and terminates the carrier sense processing.

[0068] Access parameters used in carrier sense processing include, for example, CWmin, CWmax, AIFS (Arbitration Inter Frame Space), and TXOP (Transmission Opportunity) Limit. CWmin and CWmax indicate the minimum and maximum values ​​of the contention window, respectively. The contention window is a parameter used to determine the transmission waiting time to avoid collisions. AIFS is a fixed transmission waiting time set for each access category. TXOPLimit indicates the upper limit of the channel occupation period TXOP. In other words, the shorter the CWmin, CWmax, and AIFS set for an access category, the easier it is to obtain the transmission right. Furthermore, the larger the TXOPLimit set for an access category, the larger the amount of data that can be transmitted with one transmission right.

[0069] During carrier sense processing, each of the multiple carrier sense units 253A, 253B, 253C, and 253D inputs the carrier sense processing status STS, the scheduled time Tcs for acquiring transmission rights, the channel occupation period TXOP, and the like to the transmission timing adjustment unit 280. The status STS is information indicating the status of acquisition of transmission rights through carrier sense processing. The status STS includes information such as "transmission rights being acquired," "transmission rights acquired," and "transmission rights acquisition canceled," for example.

[0070] A transmission control signal CNT is input from the transmission timing adjustment unit 280 to the carrier sense unit 253 that has acquired the transmission right. The transmission control signal CNT includes, for example, a transmission instruction and a transmission standby instruction. When a transmission instruction is input, the carrier sense unit 253 that has acquired the transmission right retrieves a data frame buffered in the corresponding queue 252. When a transmission standby instruction is input, the carrier sense unit 253 that has acquired the transmission right waits without retrieving a data frame from the corresponding queue 252.

[0071] When a transmission instruction is input, the carrier sense unit 253 that has acquired the transmission right also receives the longest channel occupation period TXOPmax from the transmission timing adjustment unit 280. The longest channel occupation period TXOPmax is the maximum value of the channel occupation periods TXOP input to the transmission timing adjustment unit 280 from each of the radio signal processing units 250, 260, and 270. When a transmission instruction is input, the carrier sense unit 253 that has acquired the transmission right adds padding to the data frame extracted from the corresponding queue 252 so that the longest channel occupation period TXOPmax is equal to the longest channel occupation period TXOPmax. The carrier sense unit 253 that has acquired the transmission right calculates the end time Te of the channel occupation period for the data frame to which the padding has been added and also obtains the rTWT-SP start time Ts of the corresponding link from the beacon management unit 233. The channel occupation period end time Te is, for example, the time when the exchange of the data frame to which the padding has been added and the Ack (Acknowledgement) corresponding to the data frame ends. The carrier sense unit 253 that has acquired the transmission right determines whether the channel occupation period end time Te is before the rTWT-SP start time Ts. If the channel occupation period end time Te is before the rTWT-SP start time Ts, the carrier sense unit 253 that has acquired the transmission right inputs the data frame with padding added to the internal collision management unit 254. If the channel occupation period end time Te is after the rTWT-SP start time Ts, the carrier sense unit 253 that has acquired the transmission right postpones the transmission of the data frame with padding added.

[0072] The internal collision management unit 254 prevents transmission collisions when two or more carrier sense units simultaneously acquire the transmission right. Specifically, for example, when multiple data frames are input simultaneously, the internal collision management unit 254 prioritizes transmission of data frames of higher priority access categories.

[0073] The transmission timing adjustment unit 280 detects the completion of carrier sense processing in all carrier sense units 253 based on the statuses STS input from each of the multiple radio signal processing units 250, 260, and 270. Until the completion of carrier sense processing in all carrier sense units 253, the transmission timing adjustment unit 280 inputs a transmission standby instruction to the carrier sense unit 253 that has acquired the transmission right. After detecting the completion of carrier sense processing in all carrier sense units 253, the transmission timing adjustment unit 280 calculates the longest channel occupation period TXOPmax for the carrier sense unit 253 that has acquired the transmission right based on the scheduled time Tcs for acquiring the transmission right and the channel occupation period TXOP. Then, the transmission timing adjustment unit 280 inputs the calculated longest channel occupation period TXOPmax together with a transmission control signal CNT including a transmission instruction to the carrier sense unit 253 that has acquired the transmission right.

[0074] 2. Operation Next, the operation of the transmitting station of the communication system according to the embodiment will be described.

[0075] When the access point 10 is a receiving station, the terminal 20 is a transmitting station. When the terminal 20 is a receiving station, the access point 10 is a transmitting station. In the following, as an example, a case where the terminal 20 is a transmitting station will be described. Note that in the following, it is assumed that a multilink ML based on the link management information shown in FIG. 2 has been established between the access point 10 and the terminal 20.

[0076] 2.1 Transmission decision processing in the radio signal processing unit 9 is a flowchart showing an example of a transmission determination process in a radio signal processing unit of a transmitting station according to the embodiment. The plurality of radio signal processing units 250, 260, and 270 execute the same transmission determination process. The transmission determination process in the radio signal processing unit 250 will be described below with reference to FIG. 9.

[0077] When the carrier sense process is started (START), each of the carrier sense units 253A, 253B, 253C, and 253D of the radio signal processing unit 250 notifies the transmission timing adjustment unit 280 of a status STS of "acquiring transmission right" (S10).

[0078] Each of the plurality of carrier sense units 253A, 253B, 253C, and 253D notifies the transmission timing adjustment unit 280 of the scheduled time Tcs for acquiring transmission rights and the channel occupation period TXOP (S11).

[0079] Each of the plurality of carrier sense units 253A, 253B, 253C, and 253D determines whether or not it has acquired the transmission right (S12).

[0080] If the transmission right is acquired (S12; yes), the carrier sense unit 253 that has acquired the transmission right notifies the transmission timing adjustment unit 280 of the status STS of "transmission right acquired" (S13).

[0081] If the transmission right cannot be acquired (S12; no), the carrier sense unit 253 that has not been able to acquire the transmission right notifies the transmission timing adjustment unit 280 of the status STS of "transmission right acquisition canceled" (S14).

[0082] After the process of S13, the carrier sense unit 253 that has acquired the transmission right waits until it receives a transmission instruction and the longest channel occupation period TXOPmax from the transmission timing adjustment unit 280 (S15).

[0083] When the transmission instruction and the longest channel occupation period TXOPmax are notified from the transmission timing adjustment unit 280, the carrier sense unit 253 extracts the data frame from the corresponding queue 252. Then, the carrier sense unit 253, which has acquired the transmission right, adds padding to the data frame so that the channel occupation period TXOP is equal to the longest channel occupation period TXOPmax (S16).

[0084] The carrier sense unit 253 that has acquired the transmission right calculates the channel occupation period end time Te based on the data frame to which padding has been added in the process of S16 (S17).

[0085] The carrier sense unit 253 that has acquired the transmission right determines whether the channel occupation period end time Te calculated in the processing of S17 is earlier than the rTWT-SP start time Ts managed by the beacon management unit 233 (S18).

[0086] If the channel occupation period end time Te is before the rTWT-SP start time Ts (S18; yes), the carrier sense unit 253 that has acquired the transmission right starts transmitting the data frame with padding added (S19). Specifically, the carrier sense unit 253 that has acquired the transmission right inputs the data frame with padding added to the internal collision management unit 254. When multiple data frames are input simultaneously, the internal collision management unit 254 selects the data frame with the highest priority. Then, the radio signal processing unit 250 converts the selected data frame into a radio signal and transmits it to the access point 10.

[0087] After the process of S14, or if the channel occupation period end time Te is later than the rTWT-SP start time Ts (S18; no), the carrier sense unit 253 postpones the transmission of the data frame (S20). Specifically, after the process of S14, the carrier sense unit 253 that was unable to acquire the transmission right postpones the transmission of the data frame. If the channel occupation period end time Te is later than the rTWT-SP start time Ts (S18; no), the carrier sense unit 253 that acquired the transmission right postpones the transmission of the data frame to which padding has been added.

[0088] After the process of S19 or S20, the transmission determination process in the radio signal processing unit 250 ends (end).

[0089] 2.2 Transmission decision processing in the transmission timing adjustment unit FIG. 10 is a flowchart illustrating an example of a transmission determination process in the transmission timing adjustment unit of the transmitting station according to the embodiment.

[0090] When the carrier sense process starts (START), the transmission timing adjustment unit 280 waits until the status STS of "acquiring transmission right" is updated to "acquired transmission right" or "acquisition of transmission right canceled" (S30).

[0091] After the process of S30, the transmission timing adjustment unit 280 determines whether the status STS, which was updated during the process of S30, has been updated to "transmission right acquired" (S31).

[0092] If the status STS is updated to "transmission right acquired" (S31; yes), the transmission timing adjustment unit 280 notifies a transmission standby instruction to the carrier sense unit 253 whose status STS has been updated to "transmission right acquired" (S32).

[0093] If the status STS is not updated to "transmission right acquired" (S31; no), or after processing S32, the transmission timing adjustment unit 280 determines whether there is a carrier sense unit 253 whose status STS is "transmission right acquired" (S33).

[0094] If there is a carrier sense unit 253 whose status STS is "acquiring transmission right" (S33; yes), the transmission timing adjustment unit 280 waits until the status STS of "acquiring transmission right" is updated to "acquired transmission right" or "acquisition of transmission right canceled" (S30). After the process of S30, the subsequent processes of S31, S32, and S33 are executed. In this way, the processes of S30 to S33 are repeated until there are no more carrier sense units 253 whose status STS is "acquiring transmission right".

[0095] If there is no carrier sense unit 253 whose status STS is "transmission right acquired" (S33; no), the transmission timing adjustment unit 280 calculates the longest channel occupation period TXOPmax among the carrier sense units 253 whose status STS is "transmission right acquired" (S34).

[0096] The transmission timing adjustment unit 280 notifies the carrier sense unit 253 whose status STS is "transmission right acquired" of a transmission instruction and the longest channel occupation period TXOPmax calculated in the process of S34 (S35).

[0097] After the process of S35, the transmission determination process in the transmission timing adjustment unit 280 ends (END).

[0098] 2.3 Example of sending decision process Fig. 11 is a diagram showing an example of a transmission determination process in a transmitting station according to an embodiment. Fig. 11 shows an example of a transmission determination process when a multilink ML is established by three pairs of STA functions (STA1, STA2, and STA3) during a certain period. Fig. 11 shows three situations in chronological order: (A), (B), and (C).

[0099] 11(A) shows the schedule of each STA function when carrier sensing processing starts. In FIG. 11(A), STA1, STA2, and STA3 are attempting to acquire the transmission right for traffic exchange during channel occupation periods TXOP1, TXOP2, and TXOP3, respectively. The end time Te1 of channel occupation period TXOP1 is after the end time Te2 of channel occupation period TXOP2. The end time Te2 of channel occupation period TXOP2 is after the end time Te3 of channel occupation period TXOP3. In addition, in STA3, a service period rTWT-SP is set from the rTWT-SP start time Ts. At this point, the service period rTWT-SP does not overlap with STA3's channel occupation period TXOP3.

[0100] (B) of FIG. 11 shows the schedule of each STA function when the carrier sense process ends. As a result of the carrier sense process, STA1 fails to acquire the transmission right. Thereby, STA1 delays the transmission of the data frame. On the other hand, STA2 and STA3 succeed in acquiring the transmission right. Therefore, the transmission timing adjustment unit 280 notifies STA2 and STA3 of the channel occupancy period TXOP2 as the longest channel occupancy period TXOPmax together with the transmission instruction.

[0101] Each of STA2 and STA3 adds padding to the data frame so as to match the longest channel occupancy period TXOPmax. Specifically, since TXOP2 = TXOPmax for STA2, no padding is added. On the other hand, since TXOP3 < TXOPmax for STA3, padding is added. Thereby, the channel occupancy period end time Te3’ of STA3 becomes equal to the channel occupancy period end time Te2 of STA2. However, due to the addition of padding, the channel occupancy period end time Te3’ in STA3 becomes after the rTWT-SP start time Ts. Therefore, STA3 delays the transmission of the data frame.

[0102] (C) of FIG. 11 shows the schedule of each STA function when the transmission determination process ends. As described above, the transmission of the data frame by STA1 and STA3 is delayed. Therefore, in this occupancy period, the data frame by STA2 is transmitted. And since the transmission of the data frame by STA3 is delayed, the overlap between the service period rTWT-SP set for STA3 and the occupancy period for transmitting the padded data frame is avoided.

[0103] 3. Effects according to the embodiment When the frequency bands assigned to the multiple channels constituting the multilink ML are close to each other, power leakage may occur between the channels. Power leakage between channels makes it difficult to transmit data on one channel while receiving data on another. For example, when data transmission is started simultaneously on multiple channels, it becomes difficult to continue transmitting data on one channel while receiving an ACK for the transmitted data on another channel. For this reason, a method is known in which padding is added to align the channel occupation period end times Te between the multiple channels constituting the multilink ML. However, adding padding may cause unintended overlap between the channel occupation period TXOP and the service period rTWT-SP. Overlapping the channel occupation period TXOP with the service period rTWT-SP is undesirable because it may hinder the exchange of low-latency traffic during the service period rTWT-SP.

[0104] According to an embodiment, a STA function that has acquired a transmission right is configured to postpone transmission of data to which padding has been added, together with data transmissions by other STA functions that have acquired a transmission right, when the channel occupation period TXOP overlaps with the service period rTWT-SP due to the addition of padding. This prevents the exchange of low-latency traffic during the service period rTWT-SP from being hindered. This provides a wireless communication environment in which low-latency traffic can be preferentially exchanged.

[0105] Furthermore, the carrier sense unit 253 that has acquired the transmission right adds padding so that its own channel occupation period TXOP is equal to the longest channel occupation period TXOPmax. Here, the channel occupation period TXOP includes the period for receiving an Ack from the receiving station. This allows the channel occupation period end times Te to be aligned among the multiple channels that make up the multilink ML. This makes it possible to avoid an operation in which data is transmitted on one channel while data is received on another channel.

[0106] Furthermore, if there is a carrier sense unit 253 that has acquired the transmission right, the transmission timing adjustment unit 280 notifies the carrier sense unit 253 that has acquired the transmission right of a transmission standby instruction. This enables simultaneous data transmission between multiple channels that make up the multilink ML. In addition, it makes it easier to estimate the padding addition period based on the longest channel occupation period TXOPmax.

[0107] Furthermore, during the service period rTWT-SP, the radio signal processor 250 transmits data with lower latency than data transmitted during periods other than the service period rTWT-SP, thereby enabling low-latency traffic to be exchanged preferentially.

[0108] The access point 10 also notifies the terminal 20 of the service period rTWT-SP by using a beacon signal, thereby enabling the terminal 20 to receive the latest rTWT-SP start time Ts and rTWT-SP duration D in a timely manner.

[0109] 4. Modifications, etc. It should be noted that the above-described embodiment can be modified in various ways. For example, in the above-described embodiment, the case where the transmission timing adjustment unit 280 notifies the carrier sense unit 253 that has "acquired the transmission right" of a transmission standby instruction until there are no more carrier sense units 253 that are "currently acquiring the transmission right" has been described, but this is not limiting. For example, the transmission timing adjustment unit 280 does not need to notify the transmission standby instruction. In this case, the carrier sense unit 253 that has "acquired the transmission right" waits until it is notified of a transmission instruction from the transmission timing adjustment unit 280.

[0110] The transmission determination process according to the above-described embodiment and modified examples can also be stored as a program that can be executed by a processor, which is a computer. Alternatively, the program can be stored in a storage medium of an external storage device such as a magnetic disk, an optical disk, or a semiconductor memory and distributed. The processor can then load the program stored in the storage medium of the external storage device and execute the transmission determination process by having its operation controlled by the loaded program.

[0111] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention. [Explanation of symbols]

[0112] 1. Communication systems 10...Access point 20...Terminal 30…Network 11,21...CPU 12,22…ROM 13,23…RAM 14,24...Wireless communication module 15...Wired communication module 25...Display 26…Storage 200...Application execution unit 110,210...LLC Processing Section 120, 220...Data processing section 130,230…Management Department 131,231...Link management information 132,232...Link Management Department 133,233...Beacon Management Department 140, 240...MAC frame processing section 150, 160, 170, 250, 260, 270...Radio signal processing unit 180, 280...Transmission timing adjustment section 251...Classification section 252...Queue 253…Career Sense Department 254…Internal conflict management department

Claims

1. a first transmission unit; A second transmission unit; a management unit that establishes a multilink with a receiving station, the multilink assigning a first channel to the first transmitting unit and a second channel to the second transmitting unit, and assigns a service period to the first channel; Equipped with the first transmitting unit is configured to postpone transmission of the first data and the padding to coincide with a second occupied period for transmitting second data by the second transmitting unit when a first occupied period for transmitting the first data and the padding overlaps with the service period; the service period is a period during which data with lower latency than the first data is preferentially exchanged; Transmitting station.

2. an adjusting unit configured to notify each of the first transmitting unit and the second transmitting unit of a longest occupation period among the second occupation period and a third occupation period for transmitting the first data when the first transmitting unit has acquired the right to transmit the first data and the second transmitting unit has acquired the right to transmit the second data, the first transmission unit is configured to, when the third occupation period is not the longest occupation period, add the padding to the first data so that an end time of the third occupation period is aligned with an end time of the longest occupation period.

2. The transmitting station of claim 1.

3. the adjustment unit is configured to, after one of the first transmission unit and the second transmission unit acquires a transmission right, cause the one transmission unit to wait for transmission of data until the other transmission unit acquires a transmission right; 3. A transmitting station according to claim 2.

4. The service period is announced by a beacon signal.

2. The transmitting station of claim 1.

5. the first occupation period includes a period for receiving an Ack (Acknowledgement) from the receiving station; 2. The transmitting station of claim 1.

6. A transmission method for a transmitting station including a first transmitting unit, a second transmitting unit, and a management unit that establishes a multilink between a receiving station, the multilink assigning a first channel to the first transmitting unit and a second channel to the second transmitting unit, and assigns a service period to the first channel, When a first occupied period for transmitting first data and padding overlaps with the service period, postponing transmission of the first data and the padding by the first transmitter to coincide with a second occupied period for transmitting second data by the second transmitter; the service period is a period during which data with lower latency than the first data is preferentially exchanged; Sending method.

7. A transmitting station including a first transmitting unit, a second transmitting unit, and a management unit that establishes a multilink between a receiving station and the first transmitting unit and assigns a first channel to the first transmitting unit and a second channel to the second transmitting unit, and that assigns a service period to the first channel, the transmitting station including: a transmission program that, when a first occupation period for transmitting first data and padding overlaps with the service period, postpones transmission of the first data and the padding in the first transmission unit to coincide with a second occupation period for transmitting second data by the second transmission unit, the service period is a period during which data with lower latency than the first data is preferentially exchanged; Sending program.

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