Access point, terminal, and communication station

Abstract

An access point in an embodiment comprises a management unit and a radio communication unit. The management unit sets a service period in which data is preferentially exchanged with a terminal included in members among terminals under management, and sets, for a communication station other than the terminals under management, a transmission suppression period so as to be overlapped with the service period. The radio communication unit transmits a radio signal including information pertaining to the terminals under management and information pertaining to the transmission suppression period to the terminals under management and a communication station capable of radio communication other than the terminals under management.

Description

Access point, terminal and communication station

[0001] The embodiments relate to an access point, a terminal and a communication station.

[0002] A wireless LAN (local area network) is known as a communication system that wirelessly connects an access point (hereinafter referred to as "AP") and a terminal. With a wireless LAN, an AP exchanges data wirelessly with terminals and other APs located within its communication range. The IEEE 802.11be standard is scheduled to specify a restricted target wake time (R-TWT) function. With the R-TWT function, an AP sets a service period during which it prioritizes the transmission and reception of data requiring low latency between the AP and a target terminal. During the service period, the AP prioritizes the exchange of data requiring low latency between the AP and the target terminal.

[0003] In a specific area such as an exhibition, office, or factory, an AP installed by an area owner or the like manages one or more terminals as terminals under its control. The installed AP then sets a service period with at least some of the terminals under its control as members, and during the set service period, it may prioritize the exchange of data requiring low latency with the terminals included in the members. When data requiring low latency is exchanged between the AP and the terminals included in the members, it is required to effectively suppress the interruption of data exchange due to data transmission from communication stations not managed by the AP. In other words, it is required that data be appropriately exchanged between the AP and the terminals included in the members during the set service period, even in a situation where communication stations other than terminals under its control are present.

[0004] IEEE P802.11beTM / D4.1, “35.8 Restricted TWT (R-TWT)”, P622-P626, September, 2023

[0005] The object of the present invention is to provide an access point that properly exchanges data with terminals included in its members during a set service period even in a situation where there are communication stations outside of its management, and to provide a terminal and communication station that are used together with the access point.

[0006] In one embodiment of the present invention, an access point includes a management unit and a wireless communication unit, and the management unit sets a service period during which data is preferentially exchanged with terminals that are members of the terminals under its management, and sets a transmission suppression period during which data transmission is suppressed for communication stations other than the terminals under its management so as to overlap with the service period. The wireless communication unit transmits wireless signals including information about the terminals under its management and information about the transmission suppression period to the terminals under its management and to communication stations other than the terminals under its management that are capable of wireless communication.

[0007] According to the present invention, it is possible to provide an access point that appropriately exchanges data with terminals included in the members during a set service period, even in a situation where there are communication stations that are not under its management, and a terminal and communication station that are used together with the access point.

[0008] FIG. 1 is a schematic diagram showing an example of the configuration of a communication system according to an embodiment. FIG. 2 is a block diagram showing an example of the hardware configuration of an AP according to an embodiment. FIG. 3 is a block diagram showing an example of the hardware configuration of a terminal according to an embodiment. FIG. 4 is a block diagram showing an example of the functional configuration of an AP according to an embodiment. FIG. 5 is a block diagram showing an example of the functional configuration of a terminal according to an embodiment. FIG. 6 is a schematic diagram showing an example of the format of a management frame including management information related to R-TWT, generated by a managed AP according to an embodiment. FIG. 7 is a schematic diagram showing an example of the format of a transmission suppression frame including information about a transmission suppression period, generated by a managed AP according to an embodiment. FIG. 8 is a flowchart showing an example of processing related to the R-TWT function performed by an AP according to an embodiment. FIG. 9 is a flowchart showing an example of processing performed by any one terminal in response to the AP performing the example processing of FIG. 8 according to an embodiment. FIG. 10 is a sequence diagram showing an example of communication operations between a managed AP, a member terminal, a non-member terminal, and a non-managed terminal among a certain R-TWT-SP in a communication system according to an embodiment.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an example of the configuration of a communication system according to an embodiment. As shown in FIG. 1, the communication system 1 includes an access point (hereinafter referred to as an "AP") 10, a terminal 20, and a network 30. The AP 10 is also referred to as a "base station" of a wireless LAN. The AP 10 communicates with a server (not shown) on the network 30 via wired or wireless communication. The terminal 20 is, for example, a smartphone, a mobile phone, a tablet PC (personal computer), a desktop PC, a laptop PC, or an IoT (Internet of Things) sensor / device. The AP 10 and the terminal 20 are also referred to as a "communication station."

[0010] The AP 10 is capable of wireless connection to a terminal 20 located within the communication coverage area CA and communicates with the terminal 20 wirelessly. The wireless communication between the terminal 20 and the AP 10 complies with, for example, the IEEE 802.11 standard. In this case, the AP 10 and the terminal 20 each have a wireless communication function based on the OSI (open systems interconnection) reference model defined by the IEEE 802.11 standard. 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 second layer, the data link layer, includes a logical link control (LLC) sublayer and a media access control (MAC) sublayer.

[0011] In the communication system 1 of FIG. 1 , the AP 10 is installed by an area owner or the like in a specific area such as an exhibition, office, or factory, and wirelessly communicates with terminals located in a communication coverage area CA and other APs in the specific area. In the example of FIG. 1 , five terminals 20A1, 20A2, 20A3, 20B1, and 20B2 are shown as terminals 20 capable of wireless communication with the AP 10. Each of the three terminals 20A1 to 20A3 is installed by an area owner or the like and is a terminal under the management of the AP 10. In other words, each of the terminals 20A1 to 20A3 belongs to the AP 10. Furthermore, each of the two terminals 20B1 and 20B2 is a communication station other than a terminal installed by an area owner or the like and is a terminal outside the management of the AP 10.

[0012] Here, AP 10 is also referred to as a "managed AP" and a "managed AP." Terminals under the management of managed AP 10, such as terminals 20A1 to 20A3, are also referred to as "managed terminals" and "associated terminals." Communication stations established by area owners, such as managed AP 10 and managed terminal 20A, are also referred to as "managed communication stations." Terminals outside the management of AP 10, such as terminals 20B1 and 20B2, are also referred to as "non-managed terminals" and "non-associated terminals." In one example, an AP outside the management of AP 10 is provided separately from AP 10. In the following description, communication stations outside the management of AP 10, including non-managed terminal 20B, i.e., communication stations other than communication stations established by area owners, are also referred to as "non-managed communication stations."

[0013] 1 shows three managed terminals 20A1 to 20A3 and two non-managed terminals 20B1 and 20B2 as communication stations capable of wireless communication with managed AP 10. However, if one or more managed terminals 20A and one or more non-managed communication stations exist within the communication coverage area CA of managed AP 10, the communication process shown below can be applied.

[0014] In one example, the AP 10 and the terminal 20 each use two or more different wireless links to perform so-called multi-link communication. In this case, the AP 10 includes an AP MLD and multiple affiliated APs, and each terminal 20 includes a non-AP MLD and multiple affiliated STAs. The AP MLD is a multi-link device (MLD) in the AP 10, and is an entity that logically connects the AP 10 to each of the terminals 20 via wireless communication. The affiliated AP is an entity that physically connects the AP 10 to each of the affiliated STAs via wireless communication. In other words, the affiliated AP has a physical configuration that exchanges data with the affiliated STAs via wireless links. The non-AP MLD is a multi-link device (MLD) in each of the terminals 20, and is an entity that logically connects the AP 10 to each of the terminals 20 via wireless communication. An affiliated STA is an entity that has a physical wireless connection with an affiliated AP, i.e., an affiliated STA has a physical configuration that exchanges data with the affiliated AP over a wireless link.

[0015] The AP 10 has an R-TWT (restricted target wake time) function, and uses the R-TWT function to ensure opportunities to exchange data requiring low latency with the terminals 20A under its control. By using the R-TWT function, the AP 10 sets a service period, and during the set service period, the AP 10 preferentially transmits and receives data requiring low latency to and from one or more target terminals among the terminals 20A under its control. The service period set using the R-TWT function is also referred to as an R-TWT-SP (service period).

[0016] In one example, the AP 10 sets multiple service periods that do not overlap with each other in terms of time. In another example, the AP 10 performs multilink communication with the terminal 20A. The AP 10 sets multiple service periods that do not overlap with each other in terms of time or wireless links. In this case, if the wireless links used to exchange data that requires low latency are different from each other, two or more service periods may be set to overlap with each other in terms of time.

[0017] During each service period, the AP 10 preferentially exchanges data requiring low latency with one or more terminals 20A included in the members of the terminals 20A under its management. That is, during each service period, one or more of the managed terminals 20A become targets for preferentially exchanging data requiring low latency with the AP 10. During each service period, only some of the managed terminals 20A may be included in the members that preferentially exchange data requiring low latency, or all of the managed terminals 20A may be included in the members that preferentially exchange data requiring low latency. Furthermore, the AP 10 may set multiple service periods that are different for each of the member managed terminals 20A.

[0018] In one example, two service periods SP1 and SP2 are set using the R-TWT function. During service period SP1, terminal 20A1 is included as a member, and AP 10 exchanges data requiring low latency with terminal 20A1, giving priority to the other communication stations. During service period SP2, terminals 20A2 and 20A3 are included as members, and AP 10 exchanges data requiring low latency with each of terminals 20A2 and 20A3, giving priority to the other communication stations.

[0019] In each of the service periods set using the R-TWT function, a terminal that is included as a member among the managed terminals 20A is also referred to as a "member terminal." In each of the service periods, a terminal that is not included as a member among the managed terminals 20A is also referred to as a "non-member terminal." In addition, the setting of a service period based on the R-TWT function is given priority to the managed terminal 20A over the non-managed terminal 20B. In one example, a service period based on the R-TWT function may not be set for each of the non-managed terminals 20B with respect to data exchange with the AP 10.

[0020] 2 is a block diagram showing an example of a hardware configuration of an AP according to an embodiment. As shown in FIG. 2, the AP 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.

[0021] The CPU 11 is a processing circuit that controls the overall operation of the AP 10. The ROM 12 is, for example, a non-volatile semiconductor memory. The ROM 12 stores programs and data for controlling the AP 10. The RAM 13 is, for example, a volatile semiconductor memory. The RAM 13 is used as a work area for the CPU 11. The wireless communication module 14 is a circuit used to send and receive data via 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 via wired signals. The wired communication module 15 is connected to the network 30.

[0022] Fig. 3 is a block diagram showing an example of the hardware configuration of a terminal according to an embodiment. In one example, each of terminals 20A1 to 20A3, 20B1, and 20B2 has the same hardware configuration as the example shown in Fig. 3. As shown in Fig. 3, terminal 20 includes, for example, a CPU 21, a ROM 22, a RAM 23, a wireless communication module 24, a display 25, and storage 26.

[0023] 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.

[0024] 4 is a block diagram showing an example of the functional configuration of an AP according to an embodiment. As shown in FIG. 4, the AP 10 functions as a computer including an upper layer processing unit 110, a management unit 120, a frame processing unit 130, and one or more wireless communication units 140. The upper layer 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 management unit 120 and the frame processing unit 130 are functional blocks that execute processing corresponding to the MAC sublayer of the second layer. The wireless communication unit 140 is a functional block that executes processing corresponding to the MAC sublayer of the second layer and layer 1.

[0025] 4, only one wireless communication unit 140 is provided. In another example, multiple wireless communication units 140 are provided in the AP 10, and the AP 10 performs multi-link communication. In this case, the management unit 120 and frame processing unit 130 in the AP 10 can operate as an AP MLD. Each of the multiple wireless communication units 140 can operate as an affiliated AP.

[0026] The upper layer processing unit 110 generates LLC packets by, for example, adding a destination service access point (DSAP) header, a source service access point (SSAP) header, etc. to data received from the network 30. The upper layer processing unit 110 then inputs the generated LLC packets to the frame processing unit 130. The upper layer processing unit 110 also extracts data from the LLC packets input from the frame processing unit 130. The upper layer processing unit 110 then transmits the extracted data to the network 30.

[0027] The management unit 120 manages wireless communications between the AP 10 and each of the terminals 20. The management unit 120 acquires information about each of the terminals 20 wirelessly connected to the AP 10, and manages wireless communications based on the information about each of the terminals 20. Furthermore, when the AP 10 performs multi-link communication, the management unit 120 acquires information about each of the multiple wireless links used in the multi-link communication, and manages wireless communications based on the information about each of the wireless links. The information about each of the multiple wireless links indicates, for each of the multiple wireless links, information about any of an identifier, a frequency band or channel to be used, and an identifier of assigned traffic.

[0028] The management unit 120 inputs management information and control information to the frame processing unit 130. The management information input from the management unit 120 to the frame processing unit 130 includes management information to be notified to any of the terminals 20 wirelessly connected to the AP 10. The control information input from the management unit 120 to the frame processing unit 130 includes control information related to control of the operation of any of the terminals 20 wirelessly connected to the AP 10. The management information and control information are also input from the frame processing unit 130 to the management unit 120. The management information input from the frame processing unit 130 to the management unit 120 includes management information to be notified to the AP 10. The control information input from the frame processing unit 130 to the management unit 120 includes control information related to control of the operation of the AP 10. The management information and control information input from the frame processing unit 130 to the management unit 120 are included in wireless signals transmitted from the terminals 20 wirelessly connected to the AP 10.

[0029] The frame processing unit 130 adds a MAC header to the LLC packet input from the upper layer processing unit 110 to generate a data frame as a MAC frame. The frame processing unit 130 also generates, as MAC frames, a management frame including management information input from the management unit 120 and a control frame including control information input from the management unit 120. The frame processing unit 130 then inputs the generated MAC frames to the wireless communication unit 140. In one example, multiple wireless communication units 140 are provided, and the frame processing unit 130 distributes the generated MAC frames to one or more of the multiple wireless communication units 140. At this time, the frame processing unit 130 determines the distribution destination of the MAC frame based on, for example, a traffic identifier (TID) associated with an access category.

[0030] Furthermore, frame processing unit 130 receives input of a MAC frame from wireless communication unit 140. When a data frame is received as a MAC frame from wireless communication unit 140, frame processing unit 130 extracts an LLC packet from the data frame and outputs the extracted LLC packet to upper layer processing unit 110. When a management frame is received as a MAC frame from wireless communication unit 140, frame processing unit 130 extracts management information from the management frame and inputs the extracted management information to management unit 120. When a control frame is received as a MAC frame from wireless communication unit 140, frame processing unit 130 extracts control information from the control frame and inputs the extracted control information to management unit 120.

[0031] The wireless communication unit 140 generates wireless frames by adding preambles and the like to MAC frames (data frames, management frames, control frames, etc.) input from the frame processing unit 130, and converts the generated wireless frames into wireless signals. The wireless communication unit 140 then transmits (radiates) the converted wireless signals via an antenna. The conversion process from the wireless frames to the wireless signals includes, for example, convolutional coding, interleaving, subcarrier modulation, inverse fast Fourier transform, orthogonal frequency division multiplexing (OFDM) modulation, and frequency conversion.

[0032] Furthermore, the wireless communication unit 140 converts a wireless signal received from one of the terminals 20 via an antenna into a wireless frame. The conversion process from the wireless signal to the wireless frame includes, for example, frequency conversion, OFDM demodulation, fast Fourier transform, subcarrier demodulation, deinterleaving, and Viterbi decoding. The wireless communication unit 140 extracts a MAC frame from the converted wireless frame and outputs the extracted MAC frame to the frame processing unit 130.

[0033] FIG. 5 is a block diagram showing an example of the functional configuration of a terminal according to an embodiment. In one example, each of terminals 20A1 to 20A3, 20B1, and 20B2 has the same functional configuration as the example shown in FIG. 5. As shown in FIG. 5, terminal 20 functions as a computer including an upper layer processing unit 210, a management unit 220, a frame processing unit 230, and one or more wireless communication units 240. Upper layer processing unit 210 is a functional block that executes processing corresponding to the LLC sublayer of layer 2 and layers 3 to 7. Management unit 220 and frame processing unit 230 are functional blocks that execute processing corresponding to the MAC sublayer of layer 2. Wireless communication unit 240 is a functional block that executes processing corresponding to the MAC sublayer of layer 2 and layer 1.

[0034] 5, only one wireless communication unit 240 is provided. In another example, multiple wireless communication units 240 are provided in the terminal 20, and the terminal 20 performs multi-link communication. In this case, the management unit 220 and frame processing unit 230 in the terminal 20 can operate as a non-AP MLD. Each of the multiple wireless communication units 240 can operate as an affiliated STA.

[0035] The upper layer processing unit 210 generates LLC packets by adding DSAP headers, SSAP headers, etc. to the data. The upper layer processing unit 210 then outputs the generated LLC packets to the frame processing unit 230. The upper layer processing unit 210 also extracts data from the LLC packets input from the frame processing unit 230. The upper layer processing unit 210 then executes an application based on the extracted data. For example, the upper layer processing unit 210 can display application information on the display 25. The upper layer processing unit 210 can also operate based on operations on an input interface.

[0036] The management unit 220 manages wireless communication between the AP 10 and the terminal 20 itself. The management unit 220 acquires information related to wireless communication between the AP 10 and the terminal 20 itself, and manages wireless communication between the AP 10 and the terminal 20 itself based on the information related to wireless communication. Furthermore, when the terminal 20 performs multi-link communication, the management unit 220 acquires information about each of a plurality of wireless links used in the multi-link communication, and manages wireless communication based on the information about each of the wireless links. The information about each of the plurality of wireless links indicates, for each of the plurality of wireless links, information about any of an identifier, a frequency band or channel to be used, and an identifier of assigned traffic.

[0037] The management unit 220 inputs management information and control information to the frame processing unit 230. The management information input from the management unit 220 to the frame processing unit 230 includes management information to be notified to either the AP 10 or another terminal 20 wirelessly connected to the AP 10. The control information input from the management unit 220 to the frame processing unit 230 includes control information related to control of the operation of either the AP 10 or another terminal 20 wirelessly connected to the AP 10. The management information and control information are also input from the frame processing unit 230 to the management unit 220. The management information input from the frame processing unit 230 to the management unit 220 includes management information to be notified to the terminal 20 that is the local station. The control information input from the frame processing unit 230 to the management unit 220 includes control information related to control of the operation of the terminal 20 that is the local station. The management information and control information input from the frame processing unit 230 to the management unit 220 are included in wireless signals transmitted from the AP 10.

[0038] Frame processing unit 230 adds a MAC header to the LLC packet input from upper layer processing unit 210 to generate a data frame as a MAC frame. Frame processing unit 230 also generates, as MAC frames, a management frame including management information input from management unit 220 and a control frame including control information input from management unit 220. Frame processing unit 230 then inputs the generated MAC frames to wireless communication unit 240. In one example, multiple wireless communication units 240 are provided, and frame processing unit 230 distributes the generated MAC frames to one or more of the multiple wireless communication units 240. At this time, frame processing unit 230 determines the distribution destination of the MAC frame based on, for example, a TID associated with an access category.

[0039] Furthermore, frame processing unit 230 receives input of a MAC frame from wireless communication unit 240. When a data frame is received as a MAC frame from wireless communication unit 240, frame processing unit 230 extracts an LLC packet from the data frame and outputs the extracted LLC packet to upper layer processing unit 210. When a management frame is received as a MAC frame from wireless communication unit 240, frame processing unit 230 extracts management information from the management frame and inputs the extracted management information to management unit 220. When a control frame is received as a MAC frame from wireless communication unit 240, frame processing unit 230 extracts control information from the control frame and inputs the extracted control information to management unit 220.

[0040] The wireless communication unit 240 generates a wireless frame by adding a preamble and the like to the MAC frame input from the frame processing unit 230. The wireless communication unit 240 then converts the generated wireless frame into a wireless signal and transmits (radiates) the converted wireless signal via an antenna. The conversion process from the wireless frame to the wireless signal is performed as described above.

[0041] The wireless communication unit 240 also converts wireless signals received from the AP 10 via the antenna into wireless frames. The conversion process from wireless signals to wireless frames is performed as described above. The wireless communication unit 240 extracts MAC frames from the converted wireless frames and outputs the extracted MAC frames to the frame processing unit 230.

[0042] The operation of the communication system 1 will be described below, focusing mainly on the operation based on the R-TWT function and the operation related to the R-TWT function. In the embodiments, the AP 10 is pre-authenticated as an access point that manages the managed terminal 20A under its management. That is, the AP 10 is pre-authenticated as an AP installed by an area owner or the like, and as a managed AP that manages the managed terminal 20A installed by the area owner or the like. The method by which the AP 10 obtains authentication is not particularly limited. In one example, the management unit 120 of the AP 10 inquires about the possibility of authentication via the network 30, thereby receiving authentication that the AP is a managed AP that manages the managed terminal 20A. In this case, for example, the management unit 120 inquires about the possibility of authentication via the network 30 using EPCS (emergency preparedness communications service) or AFC (automated frequency coordination), etc.

[0043] 4, the management unit 120 of the AP 10 includes an R-TWT management unit 121, and the management unit 120 stores a managed terminal list 122 as information about the terminals 20A under its management. The managed terminal list 122 is a list of the terminals 20A under the management of the AP 20, which is a managed AP. The managed terminal list 122 shows information about each of the managed terminals 20A. The managed terminal list 122 may show, for example, a part or all of the MAC address for each of the managed terminals 20A, or a predetermined unique ID.

[0044] Furthermore, the managed terminal list 122 may indicate the device type of each managed terminal 20A as information about that terminal 20A, rather than information directly indicating that terminal 20A. The device type indicates the category to which the terminal 20A belongs. When the device type of each managed terminal 20A is indicated as information about that terminal 20A, all terminals 20 that belong to the same device type, such as smartphones, are identified as managed terminals 20A. In one example, the managed terminal list 122 is created by an area owner or the like when installing an AP 10 that is a managed AP.

[0045] The management unit 120 of the AP 10 performs setup based on the R-TWT function when exchange of data (traffic) requiring low latency is scheduled between at least some of the managed terminals 20A and the AP 10. In the setup based on the R-TWT function, the terminals 20A with which exchange of data requiring low latency is scheduled are set as members, and the above-mentioned R-TWT-SP is set as a service period for the terminals 20A included in the members. Furthermore, the management unit 120 performs setup based on the R-TWT function to a state in which data requiring low latency is exchanged preferentially with the terminals 20A included in the members, compared to data exchange with communication stations other than the terminals 20A included in the members.

[0046] In a setup based on the R-TWT function, the management unit 120 generates management information related to the R-TWT and inputs the generated management information to the frame processing unit 130. The frame processing unit 130 generates a management frame including the management information related to the R-TWT. In one example, a beacon frame or a trigger frame is generated as the management frame including the management information related to the R-TWT. In this case, a beacon signal or a trigger signal including the management information related to the R-TWT is transmitted as a wireless signal from the wireless communication unit 140.

[0047] 6 is a schematic diagram illustrating an example of the format of a management frame including management information related to the R-TWT, generated by a managed AP in an embodiment. In the example of FIG. 6, the management frame including management information related to the R-TWT includes a field storing information regarding the start time of the R-TWT-SP, a field storing information regarding the duration of the R-TWT-SP, and a field storing information regarding a transmission suppression period having a duration of one time unit (TU). The information regarding the duration of the R-TWT-SP may indicate the duration of the R-TWT-SP from the start time, or may indicate the end time of the R-TWT-SP. When a managed terminal 20A, including a member terminal 20A, receives a wireless signal including management information related to the R-TWT, it performs communication operations based on the start time and duration of the R-TWT-SP.

[0048] The transmission suppression period indicated by the information regarding the transmission suppression period is a period during which transmission of data frames by communication stations other than the member terminal 20A is suppressed. The transmission suppression period is set, for example, using the quiet interval defined in the IEEE 802.11 standard. The time length of the quiet interval as the transmission suppression period is, for example, 1TU, which is shorter than the time length of the R-TWT-SP. Furthermore, the transmission suppression period is set to overlap in time with the R-TWT-SP. Even if each of the managed terminals 20A, including the member terminal 20A, receives information regarding the transmission suppression period, it operates its own station as if the transmission suppression period does not exist. On the other hand, when communication stations outside the management of the AP 10, including the non-managed terminal 20B, receive information regarding the transmission suppression period, they suppress (prohibit) data transmission from their own station during the transmission suppression period of 1TU.

[0049] In one example of an embodiment, a transmission suppression period of 1 TU may not be set in data exchange between the AP 10 and the member terminal 20A using the R-TWT function. In this case, a field for storing information about the transmission suppression period of 1 TU is not provided in the management frame including management information about the R-TWT.

[0050] Furthermore, a field for storing information about the member terminal 20 A may be provided in the management frame including the management information about the R-TWT. In this case, by receiving a wireless signal including the management information about the R-TWT, the managed terminal 20 A can determine whether or not the managed terminal 20 A is a member terminal 20 A that exchanges data requiring low latency with the AP 10 in the R-TWT-SP.

[0051] In one example, the information about the member terminals 20A indicates the identifiers of each managed terminal 20A, such as the addresses of each managed terminal 20A. In another example, the managed terminals 20A are divided into a plurality of groups, and the information about the member terminals 20A indicates the identifiers of the groups, such as the addresses of the groups. In this case, based on whether the managed terminal 20A belongs to a group whose identifier is indicated in the information about the member terminals 20A, each managed terminal 20A can determine whether it is a member terminal 20A that exchanges data requiring low latency with the AP 10 in the R-TWT-SP.

[0052] In one example, the AP 10 performs multi-link communication with the terminals 20 and the like that are wirelessly connected. A management frame containing management information about the R-TWT is provided with a field for storing information about the wireless link used for data exchange in the R-TWT-SP. In this case, by receiving a wireless signal containing management information about the R-TWT, the managed terminal 20A can identify the wireless link used for data exchange between the AP 10 and the member terminals 20A in the R-TWT-SP.

[0053] Furthermore, in the embodiments, in data exchange between the AP 10 and the member terminal 20A using the R-TWT function, a transmission suppression period (first transmission suppression period) is set in addition to or instead of the transmission suppression period (second transmission suppression period) having a time length of 1 TU described above. The transmission suppression period is set, for example, using a quiet interval defined in the IEEE 802.11 standard, similar to the transmission suppression period of 1 TU. Furthermore, the time length of the quiet interval as the transmission suppression period is set to be equal to or greater than 1 TU and equal to or less than the time length of the R-TWT-SP. Furthermore, the transmission suppression period is set to overlap with the R-TWT-SP in terms of time. Therefore, if the time length of the transmission suppression period is the same as the time length of the R-TWT-SP, the transmission suppression period is set to span the entire period from the start time to the end time of the R-TWT-SP.

[0054] In processing using the R-TWT function, the management unit 120 generates, as management information, information about a transmission suppression period having a time length of 1 TU or more and equal to or less than the time length of the R-TWT-SP. Information about the transmission suppression period is input from the management unit 120 to the frame processing unit 130, and the frame processing unit 130 generates, as a management frame, a transmission suppression frame including information about the transmission suppression period. Note that the time length of the transmission suppression period (first transmission suppression period) is preferably equal to or more than 1 TU, but in one example, it may be set to be shorter than 1 TU.

[0055] In one example, a beacon frame that serves as a transmission suppression frame is generated, and a beacon signal that includes information about the transmission suppression period is transmitted as a wireless signal from the wireless communication unit 140. Note that the information about the transmission suppression period may be stored in a MAC frame other than the beacon frame. In this case, for example, the MAC frame used in any of the probe request, probe response, association request, and association response serves as the transmission suppression frame that includes information about the transmission suppression period. Then, a wireless signal that includes information about the transmission suppression period is transmitted from the wireless communication unit 140 in any of the probe request, probe response, association request, and association response.

[0056] 7 is a schematic diagram illustrating an example of a format of a transmission suppression frame including information about a transmission suppression period generated by a managed AP in an embodiment. In the example of FIG. 7, the transmission suppression frame includes a Managed Network field, a Managed STAs List field, and an R-TWT E-Protection field.

[0057] The Managed Network field stores information regarding whether the AP 10 is authenticated as a managed AP that manages the managed terminal 20A. In one example, if the AP 10 is not authenticated as a managed AP, the Managed Network field is set to a field value of 0, and authentication is stored as "disable." If the AP 10 is authenticated as a managed AP, the Managed Network field is set to a field value of 1, and authentication is stored as "enable." Therefore, if the AP 10 is authenticated as a managed AP, authentication information indicating that the AP 10 is authenticated as a managed AP that manages the terminal 20A under its management is stored in the Managed Network field.

[0058] The Managed STAs List field stores information about each of the managed terminals 20A indicated in the managed terminal list 122. In one example, for each of the managed terminals 20A, information about any of a part or all of the MAC address, a predetermined unique ID, and a device type is stored in the Managed STAs List field.

[0059] The R-TWT E-Protection field stores information about the aforementioned transmission suppression period, which has a time length equal to or less than the time length of the R-TWT-SP. For example, the information about the transmission period stores information about the start time of the transmission suppression period and the time length of the transmission suppression period. Communication stations wirelessly connected to the AP 10, including the managed terminal 20A and the non-managed terminal 20B, acquire information about the transmission suppression period by receiving wireless signals converted from the transmission suppression frame.

[0060] Also, in one example, the transmission suppression frame includes a field for storing management information related to the R-TWT in addition to the Managed Network field, the Managed STAs List field, and the R-TWT E-Protection field. In this case, the transmission suppression frame includes, for example, a field for storing information related to the start time of the R-TWT-SP, a field for storing information related to the duration of the R-TWT-SP, and a field for storing information related to the transmission suppression period of 1 TU, similar to the example of FIG.

[0061] 5, the management unit 220 of each terminal 20 includes a determination unit 221. In each managed terminal 20A, when the wireless communication unit 240 receives a wireless signal including management information related to the R-TWT, the management frame including the management information related to the R-TWT is input to the frame processing unit 230. The frame processing unit 230 extracts the management information related to the R-TWT from the management frame and inputs the extracted management information to the management unit 220. As a result, the management unit 220 of each managed terminal 20A acquires the start time of the R-TWT-SP, the duration of the R-TWT-SP, etc.

[0062] Furthermore, when information about the member terminal 20A is indicated as management information about the R-TWT, the determination unit 221 of the management unit 220 of the managed terminal 20A can determine whether the member terminal 20A is a member terminal 20A that exchanges data requiring low latency with the AP 10 in the R-TWT-SP. In one example, information about the member terminal 20A is not indicated as management information about the R-TWT. In this case, before receiving a wireless signal including management information about the R-TWT, the member terminal 20A acquires in advance, by notification from the AP 10 or the like, information about the member terminal 20A that is assigned to the member terminal 20A in the R-TWT-SP.

[0063] In each of the terminals 20, including the managed terminal 20A and the non-managed terminal 20B, when the wireless communication unit 240 receives a wireless signal including information about the transmission suppression period (first transmission suppression period), the aforementioned transmission suppression frame is input as a management frame to the frame processing unit 230. The frame processing unit 230 extracts information about the transmission suppression period and information about each of the managed terminals 20A from the transmission suppression frame, and inputs the extracted information to the management unit 220. As a result, the management unit 220 of each of the terminals 20 obtains information about the start time and duration of the transmission suppression period.

[0064] Furthermore, by inputting the information extracted from the transmission suppression frame to the management unit 220, the management unit 220 of each terminal 20 can determine whether its own station is a managed terminal 20A or a non-managed terminal 20B from the information about each managed terminal 20A. If the AP 10 is authenticated as a managed AP that manages the managed terminal 20A, the management unit 220 of each terminal 20 acquires, from the information extracted from the transmission suppression frame, authentication information indicating that the AP 10 is authenticated as a managed AP that manages the managed terminal 20A. Note that each terminal 20 does not necessarily need to acquire authentication information indicating that the AP 10 is a managed AP.

[0065] In each of the terminals 20B outside the management of AP 10, i.e., non-managed terminals 20B, the management unit 220 prohibits data exchange between AP 10 and the terminal itself during the transmission suppression period in response to receiving a wireless signal including information about the transmission suppression period. On the other hand, in each of the terminals 20A under the management of AP 10, i.e., managed terminals 20A, when receiving a wireless signal including information about the transmission suppression period, the management unit 220 causes the terminal itself to operate for communication as if the transmission suppression period does not exist. Therefore, each of the managed terminals 20A can exchange data with AP 10 even during the transmission suppression period. In other words, the managed terminal 20A can exchange data with AP 10 during the transmission suppression period regardless of whether it is a member terminal 20A of the configured R-TWT-SP.

[0066] However, the transmission suppression period is set to overlap with the service period R-TWT-SP. Therefore, during the transmission suppression period that overlaps in time with the R-TWT-SP, the exchange of data (traffic requiring low latency) between the member terminal 20A and the AP 10 is prioritized over the exchange of data between the non-member terminal 20A and the AP 10. In one example, in the R-TWT-SP, each managed terminal 20A performs carrier sensing to set the member terminal 20A in a state where it is easier for the member terminal 20A to obtain the transmission right than the non-member terminal 20A. In this case, the access parameters for carrier sensing are set to a state where it is easier for the member terminal 20A to obtain the transmission right than the non-member terminal 20A.

[0067] 8 is a flowchart showing an example of processing related to the R-TWT function performed by an AP in the embodiment. The processing in the example of FIG. 8 is performed in response to setting one R-TWT-SP. That is, the processing in the example of FIG. 8 is performed every time one R-TWT-SP is set.

[0068] When the process of the example of FIG. 8 starts, the management unit 120 of the AP 10, which is a managed AP, generates management information related to the R-TWT (S301). As described above, the management information related to the R-TWT includes information related to the start time of the R-TWT-SP and information related to the duration of the R-TWT-SP. Then, the AP 10 generates a management frame that stores the management information related to the R-TWT, and transmits a wireless signal including the management information related to the R-TWT from the wireless communication unit 140 (S302). The wireless signal including the management information related to the R-TWT is transmitted to the terminal 20A under the management of the AP 10.

[0069] The management unit 120 of the AP 10 then sets the aforementioned transmission suppression period (first transmission suppression period) for communication stations outside its management, including the non-managed terminal 20B, with a time length equal to or less than the time length of the R-TWT-SP (S303). The transmission suppression period is set to overlap with the R-TWT-SP. The AP 10 then generates the aforementioned transmission suppression frame including information about each of the terminals under its management (managed terminals) 20A and information about the set transmission suppression period (S304).

[0070] Then, the AP 10 transmits the wireless signal obtained by converting the transmission suppression frame from the wireless communication unit 140 (S305). As a result, a wireless signal including information about each of the terminals 20A under its management and information about the set transmission suppression period is transmitted from the AP 10. The wireless signal including information about the transmission suppression period is transmitted to the managed terminal 20A, and is also transmitted to communication stations outside the management of the AP 10, including the non-managed terminal 20B, as long as they are communication stations capable of wireless communication with the AP 10.

[0071] Fig. 9 is a flowchart showing an example of processing performed by any one terminal in response to the AP performing the example processing of Fig. 8 in an embodiment. In one example, in response to the AP 10 transmitting a wireless signal converted from a transmission suppression frame through the example processing of Fig. 8, each of the terminals 20 capable of wireless communication with the AP 10, including the managed terminal 20A and the non-managed terminal 20B, performs the example processing of Fig. 9. When the example processing of Fig. 9 is started, the terminal 20 receives the wireless signal converted from the transmission suppression frame through the wireless communication unit 240 (S311). The example processing of Fig. 9 is started in response to receiving the wireless signal converted from the transmission suppression frame from the AP 10.

[0072] The terminal 20 then converts the received wireless signal into a transmission suppression frame and extracts from the transmission suppression frame information related to the transmission suppression period and information related to each of the managed terminals 20A. The determination unit 221 of the management unit 220 of the terminal 20 then determines whether the terminal 20 is a managed terminal 20A or not based on the information related to each of the managed terminals 20A (S312). If the terminal 20 is not a managed terminal 20A (S312-No), that is, if the terminal 20 is a non-managed communication station such as a non-managed terminal 20B, the management unit 220 prohibits data exchange between the terminal 20 and AP 10, which is a managed AP, during the transmission suppression period (first transmission suppression period) based on the information related to the transmission suppression period (S313).

[0073] If the own terminal is a managed terminal 20A (S312-Yes), the management unit 220 determines that there is no transmission suppression period and causes the own terminal to perform communication (S314). Therefore, the managed terminal 20A can exchange data with the AP 10 during the transmission suppression period. Furthermore, if the own terminal is a managed terminal 20A, the determination unit 221 of the management unit 220 determines whether the own terminal is a member terminal 20A in the R-TWT-SP (S315).

[0074] If the own terminal is a member terminal 20A (S315-Yes), the management unit 220 prioritizes data exchange between the own terminal and the AP 10 in the R-TWT-SP (S316). In this case, the management unit 220 prioritizes data exchange between the own terminal and the AP 10 in the R-TWT-SP over data exchange between a non-member managed terminal 20A and the AP 10. At this time, for example, access parameters in carrier sense are set for each terminal 20 so that the member terminal 20A is more likely to acquire the transmission right than the non-member terminal 20A.

[0075] If the own terminal is not a member terminal 20A (S315-No), that is, if the own terminal is a non-member terminal 20A, the management unit 220 prioritizes data exchange between the member terminal 20A and the AP 10 in the R-TWT-SP over data exchange between the own terminal and the AP 10. Note that even if the non-member terminal 20A among the managed terminals 20A is an R-TWT-SP, it can exchange data with the AP 10, for example, if data exchange between the member terminal 20A and the AP 10 has not been performed continuously for a certain period of time.

[0076] 10 is a sequence diagram showing an example of communication operations between a managed AP, a member terminal, a non-member terminal, and a non-managed terminal between a certain R-TWT-SP in a communication system according to an embodiment. In the example of FIG. 10, as communication operations of a managed terminal, which is a terminal under the management of a managed AP, the communication operations of one terminal included in the member of the R-TWT-SP and the operation of one terminal not included in the member of the R-TWT-SP are shown. Also, in the example of FIG. 10, the operation of one non-managed terminal is shown as communication operations of a communication station not under the management of the managed AP.

[0077] In the example of Fig. 10, a transmission suppression period (first transmission suppression period) Quiet is set with the same time length as the time length of the R-TWT-SP. Also, in the example of Fig. 10, in addition to the transmission suppression period Quiet, a transmission suppression period (second transmission suppression period) Quiet (1TU) with a time length of 1TU is set. Note that in the example of Fig. 10, it is assumed that a wireless signal containing information about the R-TWT and a wireless signal converted from a transmission suppression frame are transmitted from the managed AP before the start time of the R-TWT-SP, and the R-TWT-SP and the transmission suppression period Quiet are set as described above.

[0078] Each managed terminal identifies itself as a managed terminal based on the information stored in the Managed STAs List field of the transmission suppression frame. The managed terminal then performs communication operations assuming that the set transmission suppression period Quiet does not exist. In R-TWT-SP, managed terminals acquire the transmission right by performing carrier sense CS. At this time, access parameters for the carrier sense CS are set for each managed terminal so that member terminals that are members are more likely to acquire the transmission right than non-member terminals that are not members. The waiting time for carrier sense CS includes fixed waiting times such as AIFS (arbitration inter frame space) and DIFS (DCF (distribution coordination function) inter frame space) and a random backoff time.

[0079] In the example of FIG. 10 , a member terminal among the managed terminals transmits a wireless signal including a data frame (MAC Service Data Unit) to the managed AP based on the absence of wireless signal transmissions by other communication stations during carrier sense CS. The managed AP then returns an acknowledgement ACK to the member terminal in response to receiving the wireless signal from the member terminal. After receiving the acknowledgement ACK, for example, if there are remaining data frames that need to be transmitted to the managed AP or if the managed AP requests a retransmission, the member terminal repeats transmitting the wireless signal including the data frame to the managed AP and receiving the acknowledgement ACK from the managed AP in the same manner. In the example of FIG. 10 , the member terminal repeats transmitting the wireless signal including the data frame to the managed AP and receiving the acknowledgement ACK from the managed AP three times in the R-TWT-SP.

[0080] 10, a wireless signal is transmitted from a member terminal to a managed AP during carrier sensing of the non-member terminal. Therefore, in the R-TWT-SP, data exchange between the non-member terminal and the managed AP does not occur. However, because the non-member terminal performs communication operations as if a transmission suppression period does not exist, data exchange between the non-member terminal and the managed AP is not prohibited in the R-TWT-SP.

[0081] Furthermore, the non-managed terminal identifies itself as not being a managed terminal based on the information stored in the Managed STAs List field of the transmission suppression frame. The non-managed terminal then prohibits data exchange between itself and the managed AP during the set transmission suppression period Quiet. Here, the transmission suppression period Quiet is set to overlap with the R-TWT-SP, and in the example of FIG. 10 , the duration of the transmission suppression period Quiet is the same as the duration of the R-TWT-SP. Therefore, the non-managed terminal does not perform carrier sensing in the R-TWT-SP and does not acquire the right to transmit data frames. This prevents the transmission of wireless signals by the non-managed terminal from interrupting the transmission of wireless signals by member terminals in the R-TWT-SP.

[0082] In addition, APs (non-managed APs) that are not managed by the managed APs also perform communication operations in the R-TWT-SP in the same way as non-managed terminals. Therefore, in the R-TWT-SP, the transmission of wireless signals by non-managed APs is prevented from interrupting the transmission of wireless signals by member terminals.

[0083] As described above, in the embodiment, the management unit 120 of AP 10, which is a managed AP, sets a service period during which data is preferentially exchanged with terminals 20A that are members of the managed terminals 20A. The management unit 120 also sets a transmission suppression period, which is equal to or shorter than the service period and suppresses data transmission from communication stations other than the managed terminal 20A (e.g., terminal 20B), so that the transmission period overlaps with the service period. The AP 10 then transmits wireless signals containing information about the managed terminal 20A and information about the transmission suppression period to the managed terminal 20A and to communication stations other than the managed terminal 20A that are capable of wireless communication. As a result, non-managed communication stations, including terminal 20B, are prohibited from transmitting data to AP 10 during the transmission suppression period.

[0084] As described above, by prohibiting data transmission from non-managed communication stations to the AP 10, during a service period such as R-TWT-SP in which data requiring low latency is exchanged between the AP 10 and the member terminal 20A, the interruption of data exchange between the AP 10 and the member terminal 20A due to data transmission from a communication station not managed by the AP 10 is effectively suppressed. In other words, even in a situation where a communication station other than the managed terminal 20A exists, data is appropriately exchanged between the AP 10 and the member terminal 20A during the set service period.

[0085] The processes of the above-described embodiments and the like can be stored as a program that can be executed by a processor, which is a computer. Furthermore, the program that executes the above-described processes can be stored and distributed in a storage medium of an external storage device, such as a magnetic disk, an optical disk, or a semiconductor memory. The processor can then read the program stored in the storage medium of the external storage device, and its operation can be controlled by the read program, thereby executing the processes of the embodiments and the like.

[0086] 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.

[0087] 1...Communication system 10...Access point (AP) 20...Terminal 20A...Managed terminal (terminal) 20B...Non-managed terminal (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 110, 210...Upper layer processing unit 120, 220...Management unit 121...R-TWT management unit 122...Managed terminal list 130, 230...Frame processing unit 140, 240...Wireless communication unit 221...Determination unit

Claims

1. An access point comprising: a management unit that sets a service period during which data is preferentially exchanged with terminals that are members of the terminals under its management, and that sets a first transmission suppression period during which data transmission is suppressed for communication stations other than the terminals under its management so that the first transmission suppression period overlaps with the service period; and a wireless communication unit that transmits wireless signals containing information about the terminals under its management and information about the first transmission suppression period to the terminals under its management and to communication stations other than the terminals under its management that are capable of wireless communication.

2. The access point of claim 1, wherein the management unit generates a transmission suppression frame including a field storing the information regarding the terminal under management and a field storing the information regarding the first transmission suppression period, and the wireless communication unit transmits a wireless signal converted from the transmission suppression frame to the terminal under management and to a communication station other than the terminal under management that is capable of wireless communication.

3. The access point according to claim 1, wherein the management unit sets the first transmission suppression period to a time length of one time unit or more.

4. The access point according to claim 1, wherein the management unit sets the first transmission suppression period to a time length equal to or less than the time length of the service period.

5. The access point of claim 1, wherein the management unit notifies, via a wireless signal transmitted from the wireless communication unit, authentication information indicating that the access point is authenticated as managing the terminal under its management, in addition to the information regarding the terminal under its management and the information regarding the first transmission suppression period.

6. The access point of claim 1, wherein the management unit sets, in addition to the first transmission suppression period, a second transmission suppression period for suppressing data transmission with a duration of one time unit, overlapping with the service period, for the communication stations other than the terminals under its management.

7. A terminal used together with an access point according to any one of claims 1 to 6, and which is one of the terminals under the management of said access point, comprising: a wireless communication unit that receives from said access point said wireless signals including said information on said terminals under management and said information on said first transmission suppression period; and a management unit that, when said wireless communication unit receives said information on said terminals under management and said information on said first transmission suppression period, causes its own station to perform communication operations as if said first transmission suppression period does not exist, and, when said own station is included in said members, causes data exchange between said access point and its own station to be prioritized during said service period.

8. A communications station used together with an access point according to any one of claims 1 to 6, other than a terminal under the control of said access point, comprising: a wireless communication unit that receives from said access point said wireless signals including said information on said terminal under its control and said information on said first transmission suppression period; and a management unit that, in response to said wireless communication unit receiving said information on said terminal under its control and said information on said first transmission suppression period, prohibits data exchange between said access point and said station during said first transmission suppression period.

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