Relay station and access point

Abstract

In a relay station according to an embodiment of the present invention, a management unit establishes a link for each of a plurality of transmission / reception units one by one, thereby establishing a plurality of links in a state in which links for wireless communication are different from each other at the plurality of transmission / reception units. In response to receiving, from a transmission station, packet information relating to a packet transmitted from the transmission station through a transmission link, which is among the plurality of links, the management unit starts securing a forwarding opportunity for forwarding the packet from the transmission station to a reception station, using, as a forward link, one or more links separate from the transmission link among the plurality of links.

Description

Relay stations and access points

[0001] The embodiments relate to a relay station and an access point.

[0002] In a wireless communication network such as a wireless LAN (Local Area Network), two communication stations, such as an access point (AP) and a terminal (STA), are wirelessly connected, and packets (data) are transmitted and received between the two communication stations via wireless communication. In addition, in a wireless communication network, a packet from a transmitting station may be transferred to a receiving station via a relay station. When transferring packets via a relay station, it is necessary to suppress transfer delays.

[0003] Here, the IEEE 802.11be standard enables multi-link communication in which multiple links are established between two communication stations and packets are transmitted and received between the two communication stations via each of the multiple links. Therefore, multi-link communication can be used to transfer packets from a transmitting station to a receiving station via a relay station. By using multi-link communication to transfer packets via a relay station, after a packet is transmitted from a transmitting station to a relay station via a transmission link that is one of the multiple links, if the transmission link is busy, the packet can be transferred from the relay station to the receiving station via one or more links other than the transmission link.

[0004] However, even when a packet is transferred from a relay station to a receiving station via a link other than the transmission link as described above, it is not necessarily guaranteed that the link used for transfer from the relay station is in a transmittable state. Under these circumstances, there is a demand for a method that can effectively suppress transfer delays when transferring packets from a transmitting station to a receiving station via a relay station.

[0005] IEEE 802.11-23 / 1146r1, July 2023

[0006] An object of the present invention is to provide a relay station and an access point that can effectively suppress transfer delays when transferring packets from a transmitting station to a receiving station via the relay station.

[0007] In one embodiment of the present invention, the relay station includes a plurality of transceiver units and a management unit. The management unit establishes a link for each of the plurality of transceiver units, thereby establishing a plurality of links in different states for the plurality of transceiver units to perform wireless communication. In response to receiving, from the transmitting station, packet information regarding a packet transmitted from the transmitting station through a transmission link that is one of the plurality of links, the management unit starts reserving a forwarding opportunity to forward the packet from the transmitting station to the receiving station using one or more of the plurality of links other than the transmission link as a forwarding link.

[0008] According to the present invention, it is possible to provide a relay station and an access point that can effectively suppress transfer delays when transferring packets from a transmitting station to a receiving station via the relay station.

[0009] FIG. 1 is a block 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 a relay station according to an embodiment. FIG. 3 is a block diagram showing an example of the hardware configuration of an AP according to an embodiment. FIG. 4 is a block diagram showing an example of the functional configuration of a relay station according to an embodiment. FIG. 5 is a block diagram showing an example of the functional configuration of an AP according to an embodiment. FIG. 6 is a flowchart showing an example of processing performed by a relay station before the relay station forwards a packet from a transmitting station to a receiving station in packet forwarding via a relay station according to an embodiment. FIG. 7 is a flowchart showing an example of processing performed by an AP when the relay station requests the AP to secure a packet forwarding opportunity to the receiving station in packet forwarding via a relay station according to an embodiment. FIG. 8 is a flowchart showing an example of processing performed by a relay station when a packet forwarding opportunity to the receiving station is secured in packet forwarding via a relay station according to an embodiment. FIG. 9 is a sequence diagram showing an example of communication processing performed in packet forwarding via a relay station in a communication system according to an embodiment. FIG. 10 is a sequence diagram showing another example of communication processing performed in packet forwarding via a relay station in a communication system according to an embodiment. Fig. 11 is a flowchart showing an example of processing performed by a relay station before the relay station forwards a packet from a transmitting station to a receiving station in packet forwarding via a relay station according to a modified example. Fig. 12 is a flowchart showing an example of processing performed by a management unit of the relay station according to a modified example to adjust a schedule for forwarding packets from the relay station to a receiving station. Fig. 13 is a sequence diagram showing an example of communication processing performed in packet forwarding via a relay station in a communication system according to a modified example.

[0010] Hereinafter, embodiments will be described with reference to the drawings. In the following description, components having the same functions and configurations will be denoted by the same reference numerals.

[0011] Fig. 1 is a block 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 a relay station 10, an AP 20 which is an access point, a transmitting station 30, and a receiving station 40. In the communication system 1, the AP 20 is connected to a network 50 and communicates with a server (not shown) on the network 50 via wired or wireless communication.

[0012] In the communication system 1, a wireless communication network such as a wireless LAN is formed, and the AP 20 is capable of wireless communication with communication stations located in the communication coverage area. The communication stations capable of wireless communication with the AP 20 include terminals, and may also include APs other than the AP 20. In the example of Fig. 1, the AP 20 is capable of direct wireless communication with the relay station 10 and the receiving station 40. The AP 20 is also capable of wireless communication with the transmitting station 30 via the relay station 10.

[0013] In one example, the relay station 10 and the receiving station 40 are terminals located in a communication area of ​​the AP 20, and the transmitting station 30 is a terminal that can be wirelessly connected to the relay station 10. Also, the terminal that serves as the receiving station 40 can be wirelessly connected to the relay station 10. In another example, the relay station 10 is an AP that can be wirelessly connected to the AP 20, and the communication area of ​​the relay station 10 is different from the communication area of ​​the AP 20. And the transmitting station 30 is located in the communication area of ​​the relay station 10. Also, the receiving station 40 is located in the communication area of ​​both the AP 20 and the relay station 10.

[0014] 1, the wireless communication network formed in the communication system 1 may include one or more communication stations such as terminals in addition to the relay station 10, the AP 20, the transmitting station 30, and the receiving station 40. Each of the one or more communication stations may be capable of wireless communication with any of the relay station 10, the AP 20, the transmitting station 30, and the receiving station 40.

[0015] Furthermore, in the wireless communication network of the communication system 1, each of the relay station 10, the AP 20, the transmitting station 30, and the receiving station 40 can perform multi-link communication with other communication stations. In multi-link communication, each of the relay station 10, the AP 20, the transmitting station 30, and the receiving station 40 establishes multiple links with the communication station of the communication destination, and transmits and receives packets between the communication station of the communication destination via each of the multiple links. In multi-link communication, wireless signals are transmitted and received using different frequency bands or channels between the multiple established links. In the example of FIG. 1 , in multi-link communication, each of the relay station 10, the AP 20, the transmitting station 30, and the receiving station 40 establishes two links L1 and L2.

[0016] Furthermore, in the communication system 1, a packet can be transferred from the transmitting station 30 to the receiving station 40 via the relay station 10. In this case, the transmitting station 30 transmits the packet to the relay station 10 via wireless communication. Then, in response to completion of reception of the packet from the transmitting station 30, the relay station 10 transfers the packet from the transmitting station 30 to the receiving station 40 via wireless communication. Furthermore, in the communication system 1, the aforementioned multilink communication is used in transferring the packet (data) via the relay station 10.

[0017] The relay station 10, the AP 20, the transmitting station 30, and the receiving station 40 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.

[0018] Fig. 2 is a block diagram showing an example of a hardware configuration of a relay station according to the embodiment. Fig. 2 shows an example in which the relay station 10 is a terminal located in a communication area of ​​the AP 20. As shown in Fig. 2, the relay station 10 includes, for example, a CPU 11, a ROM 12, a RAM 13, a wireless communication module 14, a display 15, and a storage 16.

[0019] The CPU 11 is a processing circuit that controls the overall operation of the relay station 10. The ROM 12 is, for example, a non-volatile semiconductor memory. The ROM 12 stores programs and data for controlling the relay station 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 for transmitting and receiving data via wireless signals. The wireless communication module 14 is connected to an antenna. The display 15 is, for example, a liquid crystal display (LCD) or an electro-luminescence (EL) display. The display 15 displays a graphical user interface (GUI) corresponding to application software, etc. The storage 16 is a non-volatile storage device. The storage 16 stores system software, etc. of the relay station 10. The wireless communication module 14 can be wirelessly connected to the transmitting station 30 and the receiving station 40.

[0020] 3 is a block diagram showing an example of a hardware configuration of an AP according to an embodiment. As shown in FIG. 3, the AP 20 includes, for example, a central processing unit (CPU) 21, a read-only memory (ROM) 22, a random access memory (RAM) 23, a wireless communication module 24, and a wired communication module 25.

[0021] The CPU 21 is a processing circuit that controls the overall operation of the AP 20. The ROM 22 is, for example, a non-volatile semiconductor memory. The ROM 22 stores programs and data for controlling the AP 20. The RAM 23 is, for example, a volatile semiconductor memory. The RAM 23 is used as a work 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 wired communication module 25 is a circuit used for transmitting and receiving data via wired signals. The wireless communication module 24 can be wirelessly connected to the relay station 10 and the receiving station 40. The wired communication module 25 can be connected to the network 50.

[0022] Note that when the AP 20 communicates wirelessly with a server or the like on the network 50, the AP 20 is not provided with a wired communication module 25. In this case, the wireless communication module 24 can be wirelessly connected to the relay station 10 and the receiving station 40, and can also be wirelessly connected to the network 50. Furthermore, when the relay station 10 is an AP that can be wirelessly connected to the AP 20, the hardware configuration of the relay station 10 will be the same as that of the AP 20. Furthermore, when the transmitting station 30 and the receiving station 40 are each a terminal, the hardware configuration of the transmitting station 30 and the receiving station 40 will be the same as the hardware configuration of the relay station 10 shown as an example in FIG. 2 .

[0023] FIG. 4 is a block diagram showing an example of the functional configuration of a relay station according to an embodiment. FIG. 4 illustrates an example in which the relay station 10 is a terminal located in a communication area of ​​the AP 20. As shown in FIG. 4, the relay station 10 functions as a computer including an upper layer processing unit 110, a management unit 120, and multiple transceiver units 130. In the example shown in FIG. 4, two transceiver units 130-1 and 130-2 are provided as the multiple transceiver units 130. The upper layer processing unit 110 is, for example, a functional block that executes processing corresponding to the LLC sublayer of the second layer and layers 3 to 7. The management unit 120 is, for example, a functional block that executes processing corresponding to the MAC sublayer of the second layer. Each of the transceiver units 130 is, for example, a functional block that executes processing corresponding to the MAC sublayer of the second layer and layer 1.

[0024] The upper layer processing unit 110 generates packets such as LLC packets by adding a DSAP (Destination Service Access Point) header, an SSAP (Source Service Access Point) header, or the like to data. The upper layer processing unit 110 then outputs the generated packets to the management unit 120. The upper layer processing unit 110 also extracts data from packets such as LLC packets input from the management unit 120. The upper layer processing unit 110 then executes an application based on the extracted data. In one example, the upper layer processing unit 110 can display application information on the display 15. The upper layer processing unit 110 can also operate based on operations on an input interface.

[0025] The management unit 120 manages the state of wireless communication between the relay station 10 and other communication stations based on management information related to wireless communication, etc. The management information related to wireless communication includes information related to links between the relay station 10 and other communication stations. Furthermore, when the relay station 10 is performing multi-link communication, the management information related to wireless communication includes management information related to each of the multiple links established in the multi-link communication. Therefore, as in the example of FIG. 1 , when the relay station 10 is performing multi-link communication using two links L1 and L2, information related to each of the links L1 and L2 is included in the management information related to wireless communication. Furthermore, when an R-TWT (restricted target wake time) function is used, management information related to the R-TWT is included in the management information related to wireless communication.

[0026] The management unit 120 can exchange notification information related to wireless communication with each of the multiple transceiver units 130. The notification information related to wireless communication includes notification information related to links between the relay station 10 and other communication stations, and notification information related to R-TWT when the R-TWT function is in use. When the relay station 10 is performing multi-link communication, the notification information related to wireless communication includes notification information related to each of the multiple links established in the multi-link communication. The management unit 120 updates the management information related to wireless communication based on the notification information input from each of the transceiver units 130. Furthermore, the management unit 120 notifies the other communication stations of the notification information related to wireless communication via one or more of the transceiver units 130.

[0027] Furthermore, when performing multi-link communication with another communication station, the management unit 120 cooperates with the communication station with which the communication is being performed to establish multiple links to be used for the multi-link communication. In this case, the management unit 120 establishes one link for each of the multiple transceivers 130. The multiple links to be used for the multi-link communication are established so that the links for wireless communication between the multiple transceivers 130 are different from each other. In one example, the management unit 120 establishes two links L1 and L2 in the multi-link communication. The transceiver 130-1 performs wireless communication using link L1, and the transceiver 130-2 performs wireless communication using link L2.

[0028] Furthermore, the management unit 120 distributes packets (data), such as LLC packets, input from the upper layer processing unit 110 to the multiple transceiver units 130. The management unit 120 then inputs the packets (traffic) from the upper layer processing unit 110 to one or more corresponding ones of the multiple transceiver units 130. In one example, the management unit 120 allocates packets based on a traffic identifier (TID) associated with an access category. Furthermore, when a packet (data) is input from one of the multiple transceiver units 130, the management unit 120 inputs the input packet, such as an LLC packet, to the upper layer processing unit 110.

[0029] The management unit 120 also includes a schedule adjustment unit 121 and an inter-link relay unit 122. The schedule adjustment unit 121 and the inter-link relay unit 122 perform part of the processing performed by the management unit 120. The schedule adjustment unit 121 and the inter-link relay unit 122 perform processing, which will be described later, when transferring packets via the relay station 10.

[0030] Each of the multiple transceivers 130 (130-1, 130-2) includes a transmission signal processing unit 131, a reception signal processing unit 132, and a radio signal processing unit 133. In each of the transceivers 130, the transmission signal processing unit 131 performs processing related to a transmission signal to be transmitted to another communication station, etc. In each of the transceivers 130, when a packet (data) such as an LLC packet is input from the management unit 120, the transmission signal processing unit 131 adds a MAC header to the input packet to generate a data frame, which is a MAC frame. In addition, in each of the transceivers 130, when notification information is input from the management unit 120, the transmission signal processing unit 131 generates a notification frame as a MAC frame including the input notification information.

[0031] In each of the transmitter / receivers 130, a MAC frame (data frame or notification frame) is input from the transmission signal processing unit 131 to the radio signal processing unit 133. In each of the transmitter / receivers 130, the radio signal processing unit 133 generates a radio frame by adding a preamble, a PHY (physical layer) header, etc. to the MAC frame input from the transmission signal processing unit 131. Then, in each of the transmitter / receivers 130, the radio signal processing unit 133 performs a predetermined modulation operation on the generated radio frame to convert the radio frame into a radio signal, and radiates (transmits) the radio signal via an antenna. The predetermined modulation operation includes, for example, convolutional coding, interleaving, subcarrier modulation, inverse fast Fourier transform (IFFT), orthogonal frequency division multiplexing (OFDM) modulation, frequency conversion, etc.

[0032] In each of the transmitter / receivers 130, the radio signal processing unit 133 performs a predetermined demodulation operation on radio signals received from other communication stations via the antenna to convert the signals into radio frames. The predetermined demodulation operation includes, for example, frequency conversion, OFDM demodulation, fast Fourier transform (FFT), subcarrier demodulation, deinterleaving, and Viterbi decoding. In each of the transmitter / receivers 130, the radio signal processing unit 133 extracts a MAC frame from the radio frame and outputs the extracted MAC frame to the received signal processing unit 132.

[0033] In each of the transmitting / receiving units 130, the received signal processing unit 132 performs processing on received signals received from other communication stations, etc. In each of the transmitting / receiving units 130, when a MAC frame is input from the radio signal processing unit 133, the received signal processing unit 132 extracts packets (data) such as LLC packets or notification information from the input MAC frame. Then, in each of the transmitting / receiving units 130, the received signal processing unit 132 outputs the extracted packets or notification information to the management unit 120.

[0034] FIG. 5 is a block diagram showing an example of the functional configuration of an AP according to an embodiment. As shown in FIG. 5, the AP 20 functions as a computer including an upper layer processing unit 210, a management unit 220, and multiple transceiver units 230. In the example shown in FIG. 5, two transceiver units 230-1 and 230-2 are provided as the multiple transceiver units 230. The upper layer processing unit 210 is, for example, a functional block that executes processing corresponding to the LLC sublayer of the second layer and layers 3 to 7. The management unit 220 is, for example, a functional block that executes processing corresponding to the MAC sublayer of the second layer. Each of the transceiver units 230 is, for example, a functional block that executes processing corresponding to the MAC sublayer of the second layer and layer 1.

[0035] For example, upper layer processing unit 210 generates packets such as LLC packets by adding a DSAP header, an SSAP header, or the like to data received from network 50. Then, upper layer processing unit 210 inputs the generated packets to management unit 220. Furthermore, upper layer processing unit 210 extracts data from packets such as LLC packets input from management unit 220. Then, upper layer processing unit 210 transmits the extracted data to network 50.

[0036] The management unit 220, which serves as the AP-side management unit, manages the state of wireless communication between the AP 20 and other communication stations based on management information related to wireless communication, similar to the management unit 120 of the relay station 10. The management unit 220 can also exchange notification information related to wireless communication with each of the multiple transceivers 230. Similar to the management unit 120 of the relay station 10, the management unit 220 updates the management information related to wireless communication based on the notification information input from each of the transceivers 230. The management unit 220 also notifies the other communication stations of the notification information related to wireless communication via one or more of the transceivers 230.

[0037] Furthermore, when performing multi-link communication with another communication station, the management unit 220 cooperates with the communication station to establish multiple links to be used for the multi-link communication. In this case, the management unit 220 establishes one link for each of the multiple transceivers 230, just like the management unit 120 of the relay station 10. The multiple links to be used for the multi-link communication are established so that the links for wireless communication differ from one another among the multiple transceivers 230.

[0038] Furthermore, the management unit 220 distributes packets (data), such as LLC packets, input from the upper layer processing unit 210 to the multiple transceiver units 230. The management unit 220 then inputs the packets (traffic) from the upper layer processing unit 210 to one or more corresponding ones of the multiple transceiver units 230. In one example, the management unit 220 assigns packets based on a TID associated with an access category. Furthermore, when a packet (data) is input from one of the multiple transceiver units 230, the management unit 220 inputs the input packet, such as an LLC packet, to the upper layer processing unit 210.

[0039] Each of the multiple transceivers 230 (230-1, 230-2) performs the same processing as the transceiver 130 of the relay station 10 on a transmission signal to be transmitted to another communication station, etc. Therefore, when a packet (data) such as an LLC packet or notification information is input from the management unit 220, each of the transceivers 230 generates a MAC frame (data frame or notification frame). Then, each of the transceivers 230 adds a preamble and a PHY (physical layer) header, etc. to the MAC frame to generate a wireless frame, and performs a predetermined modulation operation on the generated wireless frame to transmit the wireless frame as a wireless signal. Then, each of the transceivers 230 radiates (transmits) a wireless signal via an antenna. The predetermined modulation operation is performed as described above.

[0040] Furthermore, each of the multiple transceivers 230 performs the same processing as the transceiver 130 of the relay station 10 on received signals received from other communication stations, etc. Therefore, each of the transceivers 230 performs a predetermined demodulation operation on the radio signals received via the antenna to convert them into radio frames. The predetermined demodulation operation involves the processing described above. Each of the transceivers 230 extracts a MAC frame (data frame or notification frame) from the radio frame, and extracts a packet (data) such as an LLC packet or notification information from the extracted MAC frame. Then, each of the transceivers 230 outputs the extracted packet or notification information to the management unit 220.

[0041] When the relay station 10 is an AP, the upper layer processing unit 110 of the relay station 10 performs the same processing as the upper layer processing unit 210 of the AP 20. Therefore, when the relay station 10 is an AP, the upper layer processing unit 110 transmits and receives data to and from the network 50. Similarly to the relay station 10 and the AP 20, the transmitting station 30 and the receiving station 40 each function as a computer equipped with an upper layer processing unit, a management unit, and multiple transceivers. When the transmitting station 30 and the receiving station 40 are terminals located in the communication area of ​​the relay station 10, the upper layer processing unit of each of the transmitting station 30 and the receiving station 40 performs the same processing as the upper layer processing unit 110 described above, and each of the multiple transceivers performs the same processing as the transceiver unit 130 described above. Furthermore, in each of the transmitting station 30 and the receiving station 40, the management unit performs the same processing as the management unit 120 described above, except that the transmitting station 30 and the receiving station 40 do not perform the processing of the schedule adjustment unit 121 and the inter-link relay unit 122 described below.

[0042] Next, the operation of the communication system 1 according to the embodiment will be described, and in particular, the operation of transferring a packet (data) from the transmitting station 30 to the receiving station 40 via the relay station 10 will be described. Fig. 6 is a flowchart showing an example of processing performed by the relay station before transferring a packet from the transmitting station to the receiving station in the packet transfer via the relay station according to the embodiment. The example processing of Fig. 6 is performed by the management unit 120 of the relay station 10. Furthermore, while the example processing of Fig. 6 is being performed, i.e., while the packet is being transferred via the relay station 10, the relay station 10 performs multilink communication with each of the AP 20, the transmitting station 30, and the receiving station 40.

[0043] 6 starts, the management unit 120 determines whether any of the transceiver units 130 has received packet information related to a packet (data) transmitted from the transmitting station 30 (S301). The process then waits in S301 until the packet information is received. In this embodiment, in packet transfer via the relay station 10, the packet is transmitted from the transmitting station 30 to the relay station 10 using one of the multiple links established in multi-link communication as the transmission link. Therefore, the packet is transmitted from the transmitting station 30 to the relay station 10 via the transmission link, which is one of the multiple links.

[0044] In one example, a low-latency packet that requires low latency is transmitted from the transmitting station 30 to the relay station 10 as a packet to be forwarded via the relay station 10. At this time, for example, a physical layer protocol data unit (PPDU) is transmitted from the transmitting station 30 to the relay station 10 as a data unit including the low-latency packet. Furthermore, when two links L1 and L2 are established in multi-link communication as in the example of FIG. 1 , the packet to be forwarded is transmitted from the transmitting station 30 to the relay station 10 using one of the links L1 and L2 as the transmission link.

[0045] Furthermore, packet information regarding a packet is one of the notification information regarding the wireless communication described above. The packet information includes the packet length of the packet to be transferred, and in the packet information, the packet length is indicated, for example, by the number of bytes. Furthermore, if the packet to be transferred is a low-latency packet, the packet information includes the target time for completing the transfer of the packet to the receiving station 40. However, the target time for completing the transfer of the packet to the receiving station 40 does not necessarily have to be indicated as the packet information.

[0046] In one example, before a packet is transmitted from the transmitting station 30 to the relay station 10, the transmitting station 30 transmits packet information to the relay station 10. At this time, the packet information is transmitted to the relay station 10 via, for example, one or more of the transmission links through which the packet is transmitted. Note that, if one or more of the links other than the transmission link among the multiple links is in an idle state, the transmitting station 30 may transmit the packet information to the relay station 10 via a link other than the transmission link. In this case, the link through which the packet information is transmitted is different from the transmission link through which the packet is transmitted from the transmitting station 30 to the relay station 10.

[0047] In another example, a data unit including a packet such as a PPDU is transmitted from the transmitting station 30 to the relay station 10, and packet information is embedded in the data unit including the packet. In this case, the relay station 10 acquires the packet information by receiving the data unit including the packet to be transferred from the transmitting station 30. The packet information is embedded in the beginning of the data unit including the packet to be transferred, for example, in the SIG (signal) field of the data unit including the packet. Furthermore, the packet length may be indicated as packet information at the beginning of the PPDU, which is a data unit including the packet.

[0048] Furthermore, when packet information is transmitted from the transmitting station 30 before the transmission of the packet, information on the transmission link used for transmitting the packet may be included in the packet information. In particular, when the packet information is transmitted through a link other than the transmission link through which the packet is transmitted, or when the packet information is transmitted using only some of the multiple transmission links through which the packet is transmitted, information on the transmission link, such as the identifier of the transmission link, is included in the packet information.

[0049] 6 , when any of the transmitter / receiver units 130 of the relay station 10 receives packet information (S301—Yes), the transmitter / receiver unit 130 that has received a received signal including the packet information extracts the packet information from the received signal as notification information. Then, the transmitter / receiver unit 130 that has received the packet information outputs the extracted packet information to the management unit 120. Then, the schedule adjustment unit 121 of the management unit 120 adjusts the schedule for transferring packets from the relay station 10 to the receiving station 40 based on the packet information (S302).

[0050] In adjusting the transfer schedule, the schedule adjustment unit 121 sets a transfer link to be used for transferring packets to the receiving station 40 from among the multiple links established in the multi-link communication. A link other than the transmission link used for transmitting packets from the transmitting station 30 to the relay station 10 is set as the transfer link. The link set as the transfer link may be one or more links other than the transmission link. Therefore, the number of links set as the transfer link may be one or more. Here, as in the example of FIG. 1 , assume that two links L1 and L2 are established in the multi-link communication, and link L1 is used as the transmission link. In this case, the schedule adjustment unit 121 sets link L2, other than link L1, as the transfer link to be used for transferring packets from the relay station 10.

[0051] In adjusting the transfer schedule, the schedule adjustment unit 121 sets the time to transfer a packet to the receiving station 40 over the transfer link. At this time, the schedule adjustment unit 121 predicts the timing when reception of the packet from the transmitting station 30 at the relay station 10 will end, and sets the time to transfer the packet to the receiving station 40 after the predicted timing when reception of the packet will end. Furthermore, the schedule adjustment unit 121 uses the packet length included in the packet information to calculate the length of time required to transfer the packet from the relay station 10 to the receiving station 40. At this time, the length of time required for transfer is calculated based on the packet length and the MCS (Modulation and Coding Scheme) of the link set as the transfer link.

[0052] The schedule adjustment unit 121 sets the time to transfer the packet to the receiving station 40 based on the calculation result of the length of time required for transfer and the target time for completing the transfer of the packet to the receiving station 40. At this time, the time to transfer the packet to the receiving station 40 is set so that the transfer of the packet to the receiving station 40 will be completed before the target time. In addition, in one example, if the target time is not indicated in the packet information, the schedule adjustment unit 121 considers the packet to be a low-latency packet and sets the target time for completing the transfer of the packet to the receiving station 40. Then, the schedule adjustment unit 121 sets the time to transfer the packet to the receiving station 40 so that the transfer of the packet to the receiving station 40 will be completed before the set target time.

[0053] After adjusting the schedule for transferring packets to the receiving station 40 as described above, the management unit 120 requests the AP 20 to reserve a transfer opportunity for transferring packets to the receiving station 40 (S303). At this time, the request for reserving a transfer opportunity is made by transmitting a wireless signal that serves as a request signal from the relay station 10 to the AP 20. The request signal indicates the link set as the transfer link, the time set as the time for transfer, and the like as the result of adjusting the transfer schedule.

[0054] The management unit 120 transmits a request signal to the AP 20 via a link other than the transmission link used to transmit packets from the transmitting station 30 to the relay station 10. The link used to transmit the request signal may be a link set as a forwarding link, or may be a link other than the forwarding link, as long as it is a link other than the transmission link. Here, assume that two links L1 and L2 are established in multi-link communication as shown in the example of FIG. 1 , and link L1 is used as the transmission link. In this case, the management unit 120 requests the AP 20 to secure a forwarding opportunity to forward packets to the receiving station 40 using link L2, which is other than link L1.

[0055] Furthermore, in parallel with the processing of S302 and S303, the management unit 120 causes the transceiver unit 130, which performs wireless communication via the transmission link, to receive packets from the transmitting station 30 (S304). As a result, the management unit 120 acquires packets transmitted from the transmitting station 30, i.e., packets to be transferred to the receiving station 40. Here, as in the example of FIG. 1, two links L1 and L2 are established in multi-link communication, and link L1 is used as the transmission link. In this case, the transceiver unit 130-1, which performs wireless communication via link L1, receives packets from the transmitting station 30.

[0056] 6 is performed, the management unit 120, in response to receiving packet information from the transmitting station 30, starts securing a transfer opportunity for transferring the packet from the transmitting station 30 to the receiving station 40 using one or more transfer links other than the transmission link among the multiple links. Then, in parallel with receiving the packet from the transmitting station 30 via the transmission link, the management unit 120 performs processing to secure a transfer opportunity for the packet to the receiving station 40 using a link other than the transmission link among the multiple links.

[0057] 7 is a flowchart showing an example of processing performed by an AP when a relay station requests an AP to secure a packet forwarding opportunity to a receiving station in packet forwarding via a relay station according to an embodiment. The example processing of FIG. 7 is performed by the management unit (AP-side management unit) 220 of the AP 20. When the example processing of FIG. 7 starts, the management unit 220 determines whether the AP 20 has received the request signal from the relay station 10 requesting the securing of a forwarding opportunity (S311). The processing then waits in S311 until the request signal is received.

[0058] When a request signal is received (S311—Yes), the management unit 220 determines whether to grant the request to secure a forwarding opportunity (S312). At this time, it is determined whether the packet can be forwarded at the time set as the time for forwarding via the link set as the forwarding link. The determination in S312 is made based on the communication status of communication stations located in the communication area of ​​the AP 20, including the relay station 10 and the receiving station 40, and is made using the above-mentioned management information related to wireless communication. For example, in the determination in S312, it is confirmed based on the management information, etc., whether a service period based on the R-TWT function has already been set by another communication station at the time set as the time for forwarding.

[0059] If the request to secure a transfer opportunity is permitted (S312-Yes), the management unit 220 notifies the relay station 10 of information regarding the secured transfer opportunity (S313). At this time, the AP 20 notifies the relay station 10 of the information regarding the secured transfer opportunity by transmitting a notification signal indicating the information regarding the transfer opportunity as a wireless signal from the AP 20 to the relay station 10. The information regarding the transfer opportunity indicates the time of the secured transfer opportunity and the transfer link to be used for transfer at the transfer opportunity. The transfer opportunity is secured by, for example, setting a service period based on the R-TWT function.

[0060] Furthermore, the management unit 220 notifies communication stations located in the communication area including the relay station 10 and the receiving station 40 of information regarding the secured transfer opportunity (S313). Therefore, a wireless signal serving as a notification signal is transmitted from the AP 20 to all communication stations located in the communication area. As a result, communication stations belonging to the same BSS (basic service set) as the relay station 10 and the receiving station 40 obtain information regarding the secured transfer opportunity. Therefore, in the communication area of ​​the AP 20, communication stations other than the relay station 10 and the receiving station 40 are prohibited from performing wireless communication using a transfer link for the secured transfer opportunity.

[0061] Furthermore, a notification signal notifying information about the secured transfer opportunity is transmitted from the AP 20 via a link other than the transmission link used for transmitting packets from the transmitting station 30 to the relay station 10. In one example, the notification signal is also transmitted via the link used for transmitting a request signal from the relay station 10 to the AP 20. The notification of information about the secured transfer opportunity is also transmitted to the transmitting station 30 directly from the AP 20 or via the relay station 10 or the like.

[0062] If the request to reserve a forwarding opportunity is not permitted (S312-No), the management unit 220 notifies the relay station 10 that a forwarding opportunity will not be reserved (S314). At this time, the notification is made by transmitting a notification signal indicating that a forwarding opportunity will not be reserved from the AP 20 to the relay station 10 as a wireless signal. In this case, the notification signal is also transmitted from the AP 20 via a link other than the transmission link; for example, the notification signal is also transmitted via the link used to transmit the request signal from the relay station 10 to the AP 20.

[0063] 8 is a flowchart showing an example of processing performed by a relay station when a packet transfer opportunity to a receiving station is secured in packet transfer via a relay station according to an embodiment. The example processing of FIG. 8 is performed by the management unit 120 of the relay station 10, for example, when information regarding the secured transfer opportunity is notified by the AP 20 in S313 of FIG. 7. When the example processing of FIG. 8 starts, the management unit 120 determines whether the relay station 10 has received a notification signal indicating information regarding the secured transfer opportunity (S321). The processing then waits in S321 until the notification signal is received.

[0064] If a notification signal is received (S321-Yes), the management unit 120 determines whether or not the relay station 10 has finished receiving the packets transmitted from the transmitting station 30 via the transmission link (S322).Then, the process waits in S322 until the relay station 10 has finished receiving the packets.

[0065] When the reception of the packet at the relay station 10 is completed (S322-Yes), the management unit 120 transfers the packet from the transmitting station 30 to the receiving station 40 at the secured transfer opportunity (S323). At this time, the packet is transferred to the receiving station 40 through the link set as the transfer link. Therefore, the packet is transferred to the receiving station 40 through a transfer link different from the transmission link used for transmission from the transmitting station 30 to the relay station 10.

[0066] In the process of S323, the packet is moved from the transmission link to the transfer link via the inter-link relay unit 122 of the management unit 120. That is, the packet received from the transmitting station 30 is input to the inter-link relay unit 122 from the transmitting / receiving unit 130, which performs wireless communication via the transmission link. Then, the inter-link relay unit 122 inputs the packet to be transferred to the receiving station 40 to the transmitting / receiving unit 130, which performs wireless communication via the transfer link.

[0067] Furthermore, when a packet is transferred to the receiving station 40 via multiple transfer links during a reserved transfer opportunity, in one example, the relay station 10 generates the same number of packets as the number of transfer links by, for example, duplicating the packet received from the transmitting station 30. Then, on each of the multiple transfer links, one of the multiple packets is transferred from the relay station 10 to the receiving station 40. In this case, even if an error occurs in the transfer of the packet on some of the multiple transfer links, the transferred packet will be properly acquired by the receiving station 40 as long as the packet is properly transferred on the remaining transfer links.

[0068] Furthermore, in another example, when a packet is transferred to the receiving station 40 via multiple transfer links, the relay station 10 divides the packet received from the transmitting station 30 into the same number of divided packets as the number of transfer links. Then, in each of the multiple transfer links, one of the multiple divided packets is transferred from the relay station 10 to the receiving station 40. In this case, the relay station 10 divides the packet received from the transmitting station 30 into multiple divided packets for transfer, thereby reducing the length of time required for transfer from the relay station 10 to the receiving station 40.

[0069] Furthermore, in this embodiment, if the relay station 10 is notified by the process of S314 or the like that no forwarding opportunity is secured, after the relay station 10 has finished receiving the packet from the transmitting station 30, it forwards the packet to the receiving station 40, for example, via the transmission link used to transmit the packet from the transmitting station 30. Furthermore, if the transmission link is busy at the time of forwarding the packet to the receiving station 40, it determines whether or not there is a link other than the transmission link through which the packet can be forwarded. If there is a link through which the packet can be forwarded, such as an idle link, it forwards the packet to the receiving station 40 via one or more of the links through which the packet can be forwarded.

[0070] 7 is performed by the management unit 220 of the AP 20. If the request to reserve a forwarding opportunity is not permitted, the management unit 220 determines whether a forwarding opportunity for the packet to the receiving station 40 can be reserved on a link other than the forwarding link set in the request from the relay station 10. At this time, it is confirmed whether a forwarding opportunity for the packet can be reserved on a link other than the transmitting link and other than the forwarding link set in the request from the relay station 10.

[0071] If there is a link for which a forwarding opportunity can be secured, the management unit 220 sets one or more of the links for which a forwarding opportunity can be secured as forwarding links and secures a forwarding opportunity for the packet to the receiving station 40. The management unit 220 then notifies the communication stations located in the communication coverage area including the relay station 10 and the receiving station 40 of information regarding the secured forwarding opportunity. In this case, the forwarding link indicated in the information regarding the secured forwarding opportunity is different from the link set as the forwarding link in the request from the relay station 10. The information regarding the secured forwarding opportunity is also notified to the transmitting station 30 directly from the AP 20 or via the relay station 10 or the like.

[0072] In one example, in multi-link communication, three links L1, L2, and L3 are established, and a packet is transmitted from the transmitting station 30 to the relay station 10 using link L1 as the transmission link. The relay station 10 then requests the AP 20 to reserve a forwarding opportunity using link L2 as the forwarding link. The AP 20 then does not grant the request from the relay station 10, but reserves a forwarding opportunity for the packet to the receiving station 40 using link L3 as the forwarding link. The AP 20 then notifies communication stations located in a communication coverage area including the relay station 10 and the receiving station 40 of information regarding the forwarding opportunity using link L3 as the forwarding link. The information regarding the forwarding opportunity using link L3 as the forwarding link is also notified to the transmitting station 30.

[0073] 9 is a sequence diagram showing an example of communication processing performed in packet forwarding via a relay station in a communication system according to an embodiment. In the example shown in FIG. 9, two links L1 and L2 are established in multi-link communication, and the transmitting station 30 transmits packet information (info) to the relay station 10 via link L1 (S401). The transmission of the packet information is performed before the transmission of a packet from the transmitting station 30 to the relay station 10. Then, upon completion of reception of the packet information, the relay station 10 returns an ACK signal (ack) indicating that the packet information has been properly received to the transmitting station 30 via link L1 (S402).

[0074] Upon receiving the ACK signal from the relay station 10, the transmitting station 30 transmits a PPDU containing the packet to the relay station 10 via link L1, which serves as the transmission link (S403). Furthermore, in parallel with receiving the packet from the transmitting station 30, the relay station 10 transmits a request signal (req) to the AP 20 via link L2, requesting the AP 20 to reserve a packet forwarding opportunity for the packet to the receiving station 40 (S404). In the example of FIG. 9 , the AP 20 grants the request from the receiving station 40 and reserves a forwarding opportunity A1 using link L2, which is separate from the transmission link, as the forwarding link. The AP 20 then transmits a notification signal (acc) indicating information about the reserved forwarding opportunity A1 to the transmitting station 30, the relay station 10, and the receiving station 40 via link L2 (S405). Thus, in parallel with receiving the packet from the transmitting station 30, the relay station 10 reserves a packet forwarding opportunity A1 for the receiving station 40. The transfer opportunity A1 is secured before the target time Ytar for completing the transfer of the packet to the receiving station 40 .

[0075] Then, when reception of the packet is completed, the relay station 10 returns an ACK signal (ack) indicating that the packet was properly received to the transmitting station 30 via link L1 (S406). In parallel with returning the ACK signal to the transmitting station 30, the relay station 10 also transfers a PPDU including the received packet to the receiving station 40 via link L2, which is a transfer link (S407). The transfer of the packet from the relay station 10 to the receiving station 40 is performed at the reserved transfer opportunity A1. Then, when reception of the packet is completed, the receiving station 40 returns an ACK signal (ack) indicating that the packet was properly received to the relay station 10 via link L2 (S408).

[0076] 10 is a sequence diagram showing another example of a communication process performed in a communication system according to an embodiment, in which packets are transferred via a relay station. In the example shown in FIG. 10, two links L1 and L2 are established in multi-link communication. The transmitting station 30 transmits a PPDU, in which packet information (info) is embedded, as a data unit containing a packet to the relay station via the transmitting link L1 (S411). At this time, the relay station 10 receives the packet information embedded in the beginning of the PPDU (S412).

[0077] Then, upon receiving the packet information, the relay station 10, in parallel with receiving the packet from the transmitting station 30, transmits a request signal (req) to the AP 20 via link L2 requesting the reservation of a packet forwarding opportunity to the receiving station 40 (S413). In the example of FIG. 10 , the AP 20 grants the request from the receiving station 40 and reserves a forwarding opportunity A2 using link L2, which is different from the transmitting link, as the forwarding link. Then, the AP 20 transmits a notification signal (acc) indicating information about the reserved forwarding opportunity A2 to the transmitting station 30, the relay station 10, and the receiving station 40 via link L2 (S414). Thus, the relay station 10, in parallel with receiving the packet from the transmitting station 30, reserves a packet forwarding opportunity A2 to the receiving station 40. The forwarding opportunity A2 is reserved before the target time Ytar for ending the packet forwarding to the receiving station 40.

[0078] Then, when reception of the packet is completed, the relay station 10 returns an ACK signal (ack) indicating that the packet was properly received to the transmitting station 30 via link L1 (S415). In parallel with returning the ACK signal to the transmitting station 30, the relay station 10 also transfers a PPDU including the received packet to the receiving station 40 via link L2, which is a transfer link (S416). The transfer of the packet from the relay station 10 to the receiving station 40 is performed at the reserved transfer opportunity A2. Then, when reception of the packet is completed, the receiving station 40 returns an ACK signal (ack) indicating that the packet was properly received to the relay station 10 via link L2 (S417).

[0079] As described above, in this embodiment, in response to the relay station 10 receiving, from the transmitting station 30, packet information related to a packet transmitted from the transmitting station 30 through a transmission link that is one of the multiple links, the management unit 120 of the relay station 10 starts reserving a transfer opportunity for the packet from the transmitting station 30 to be transferred to the receiving station 40 using one or more transfer links other than the transmission link among the multiple links. This makes it possible to reserve a transfer opportunity for the packet to the receiving station 40 while the relay station 10 is receiving the packet from the transmitting station 30, i.e., before the timing of transferring the packet from the relay station 10 to the receiving station 40. By reserving a transfer opportunity for the packet to the receiving station 40 in advance, transfer delays are effectively suppressed in the transfer of the packet from the transmitting station 30 to the receiving station 40 via the relay station 10.

[0080] Furthermore, by ensuring in advance an opportunity to transfer a packet to the receiving station 40, the relay station 10 can transfer the packet to the receiving station 40 via a transfer link separate from the transmission link in parallel with returning an ACK signal indicating that the packet has been properly received to the transmitting station 30, as shown in the examples of Figures 9 and 10. This effectively reduces transfer delays in the transfer of packets from the transmitting station 30 to the receiving station 40 via the relay station 10.

[0081] Furthermore, in this embodiment, in order to secure a packet transfer opportunity to the receiving station 40 in advance, the relay station 10 performs processing to secure a packet transfer opportunity to the receiving station 40 in parallel with receiving a packet from the transmitting station 30 through the transmission link. The relay station 10 then performs processing to secure a packet transfer opportunity to the receiving station 40 using a link separate from the transmission link. The processing to secure a packet transfer opportunity to the receiving station 40 appropriately prevents the transmission of packets from the transmitting station 30 to the relay station 10 from being interrupted.

[0082] In one modified example, the communication system 1 does not include the AP 20. In this case, for example, an AP located in an area where the transmitting station 30 and the receiving station 40 can communicate with each other serves as the relay station 10. Alternatively, a terminal capable of wireless communication with both the transmitting station 30 and the receiving station 40 may serve as the relay station 10.

[0083] 11 is a flowchart showing an example of processing performed by a relay station before the relay station forwards a packet from a transmitting station to a receiving station in a packet forwarding via a relay station according to a modified example. The example processing of FIG. 11 is performed by the management unit 120 of the relay station 10. Furthermore, while the example processing of FIG. 11 is being performed, i.e., while the packet forwarding is being performed via the relay station 10, the relay station 10 performs multilink communication with each of the transmitting station 30 and the receiving station 40.

[0084] 11 starts, similarly to the above-described embodiment, the management unit 120 determines whether any of the transceiver units 130 has received packet information regarding a packet (data) transmitted from the transmitting station 30 (S331). If any of the transceiver units 130 of the relay station 10 has received the packet information (S331—Yes), the schedule adjustment unit 121 of the management unit 120 adjusts the schedule for transferring the packet from the relay station 10 to the receiving station 40 based on the packet information (S332). In addition, in parallel with the schedule adjustment process of S332, the management unit 120 causes the transceiver units 130 that perform wireless communication via the transmission link to receive the packet from the transmitting station 30 (S333).

[0085] 12 is a flowchart showing an example of a schedule adjustment process for transferring packets from a relay station to a receiving station, the process being performed by a management unit of a relay station according to a modified example. When the schedule adjustment process of the example shown in FIG. 12 is started, the schedule adjustment unit 121 of the management unit 120 sets a time for transferring packets to the receiving station 40 (S341). At this time, the schedule adjustment unit 121 calculates the length of time required for transferring packets from the relay station 10 to the receiving station 40, as described above, using the packet length included in the packet information. Then, based on the calculation result of the length of time required for transfer and the target time for completing the transfer of packets to the receiving station 40, the schedule adjustment unit 121 sets the time for transferring packets to the receiving station 40 so that the transfer of packets to the receiving station 40 will be completed before the target time.

[0086] The schedule adjustment unit 121 then determines whether or not there is a link among the multiple links used in multi-link communication that can secure a transfer opportunity at the set transfer time (S342). At this time, it is confirmed whether or not a packet transfer opportunity can be secured for a link other than the transmission link used to transmit the packet from the transmitting station 30 to the relay station 10. If a link that can secure a transfer opportunity is found (S342—Yes), the schedule adjustment unit 121 sets one or more of the links that can secure a transfer opportunity as the transfer link to be used to transfer the packet from the relay station 10 to the receiving station 40 (S343).

[0087] The schedule adjustment unit 121 then reserves a packet transfer opportunity to the receiving station 40 through the set transfer link (S344). At this time, the packet transfer opportunity is reserved on the transfer link at the time set in the processing of S341. The management unit 120 then notifies communication stations located in the communication coverage area including the transmitting station 30 and the receiving station 40 of information about the reserved transfer opportunity (S345). As a result, communication stations other than the relay station 10 and the receiving station 40 are prohibited from performing wireless communication using the transfer link during the reserved transfer opportunity.

[0088] Furthermore, if there is no link for which a transfer opportunity can be secured (S342-No), the processes of S343 to S345 are not performed. Therefore, a transfer opportunity for the packet to the receiving station 40 is not secured, and the adjustment process of the example of FIG. 12 ends. If a transfer opportunity is not secured, after the relay station 10 has finished receiving the packet from the transmitting station 30, it transfers the packet to the receiving station 40 in the same manner as in the above-described embodiment.

[0089] 13 is a sequence diagram showing an example of communication processing performed in a communication system according to a modified example when packets are transferred via a relay station. In the example shown in FIG. 13, two links L1 and L2 are established in multi-link communication. Before transmitting a packet, the transmitting station 30 transmits packet information (info) via link L1 to the relay station 10, which is an AP (S421). Then, upon completion of reception of the packet information, the relay station 10 returns an ACK signal (ack) indicating that the packet information has been properly received to the transmitting station 30 via link L1 (S422).

[0090] Upon receiving the ACK signal from the relay station 10, the transmitting station 30 transmits a PPDU including the packet to the relay station 10 via link L1, which serves as the transmission link (S423). Furthermore, the relay station 10 performs a process of securing a packet transfer opportunity to the receiving station 40 in parallel with receiving the packet from the transmitting station 30. In the example of FIG. 13 , the relay station 10 secures a transfer opportunity A3 using link L2, which is separate from the transmission link, as the transfer link through the aforementioned transfer schedule adjustment process. The relay station 10 then transmits a notification signal (note) indicating information about the secured transfer opportunity A3 to the transmitting station 30 and the receiving station 40 via link L2 (S424). Thus, the relay station 10 secures a packet transfer opportunity A3 to the receiving station 40 in parallel with receiving the packet from the transmitting station 30. The transfer opportunity A3 is secured before the target time Ytar for completing the packet transfer to the receiving station 40.

[0091] Then, when reception of the packet is completed, the relay station 10 returns an ACK signal (ack) indicating that the packet was properly received to the transmitting station 30 via link L1 (S425). In parallel with returning the ACK signal to the transmitting station 30, the relay station 10 also transfers a PPDU including the received packet to the receiving station 40 via link L2, which is a transfer link (S426). The transfer of the packet from the relay station 10 to the receiving station 40 is performed at the reserved transfer opportunity A3. Then, when reception of the packet is completed, the receiving station 40 returns an ACK signal (ack) indicating that the packet was properly received to the relay station 10 via link L2 (S427).

[0092] This modification also achieves the same effects and advantages as the above-described embodiment. That is, this modification also makes it possible to secure an opportunity to transfer a packet to the receiving station 40 at the stage when the relay station 10 is receiving a packet from the transmitting station 30. By securing an opportunity to transfer a packet to the receiving station 40 in advance, transfer delays are effectively suppressed when a packet is transferred from the transmitting station 30 to the receiving station 40 via the relay station 10.

[0093] Although the above-described example mainly describes a case where two links are established in multi-link communication, the management unit 120 of the relay station 10 and the like perform the same processing as in any of the above-described examples when three or more links are established in multi-link communication. That is, in response to receiving, from the transmitting station 30, packet information regarding a packet transmitted from the transmitting station 30 through a transmission link that is one of the multiple links, the management unit 120 of the relay station 10 starts securing a transfer opportunity for the packet from the transmitting station 30 to be transferred to the receiving station 40 using one or more transfer links other than the transmission link among the multiple links. Then, in parallel with receiving the packet from the transmitting station 30 through the transmission link, the management unit 120 performs processing for securing a transfer opportunity for the packet to the receiving station 40 using a link other than the transmission link among the multiple links.

[0094] The configuration for executing the communication processing of the above-described embodiment and the like can also be applied to a system configuration in which the transmitting station 30 and the receiving station 40 can communicate with the AP 20 only via the relay station 10. In this case, the relay station 10 is, for example, an AP belonging to the AP 20. In such a system configuration, as long as the relay station 10 is configured to perform multi-link communication with the transmitting station 30 and the receiving station 40, communication with the AP 20 may be performed wirelessly or via a wired connection.

[0095] 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.

[0096] 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.

[0097] DESCRIPTION OF SYMBOLS 1...Communication system 10...Relay station 11, 21...CPU 12, 22...ROM 13, 23...RAM 14, 24...Wireless communication module 15...Display 16...Storage 20...AP 25...Wired communication module 30...Transmitting station 40...Receiving station 50...Network 110, 210...Upper layer processing unit 120, 220...Management unit 121...Schedule adjustment unit 122...Inter-link relay unit 130 (130-1, 130-2), 230 (230-1, 230-2)...Transmitting / receiving unit 131...Transmitting signal processing unit 132...Receiving signal processing unit 133...Wireless signal processing unit

Claims

1. A relay station comprising: a plurality of transmission / reception units; and a management unit configured to establish a plurality of links in different states with respect to each other among the plurality of transmission / reception units by establishing one link for each of the plurality of transmission / reception units, and to start ensuring a transfer opportunity to transfer a packet from a transmitting station to a receiving station using one or more links among the plurality of links other than the transmission link, which is one of the plurality of links, in response to receiving packet information regarding the packet transmitted from the transmitting station through the transmission link.

2. The relay station according to claim 1, wherein the management unit performs a process of ensuring the transfer opportunity of the packet to the receiving station using a link other than the transmission link among the plurality of links in parallel with receiving the packet from the transmitting station through the transmission link.

3. The relay station according to claim 1 or 2, wherein when the management unit ensures the transfer opportunity of the packet to the receiving station, the management unit transfers the packet to the receiving station through the transfer link at the ensured transfer opportunity in response to the reception of the packet from the transmitting station through the transmission link being completed.

4. The relay station according to claim 1 or 2, wherein the management unit starts ensuring the transfer opportunity of the packet to the receiving station in response to receiving the packet information before the packet is transmitted from the transmitting station.

5. The relay station according to claim 1 or 2, wherein the management unit starts ensuring the transfer opportunity of the packet to the receiving station in response to receiving the packet information embedded in a data unit including the packet from the transmitting station.

6. The relay station according to claim 1 or 2, wherein in a process of ensuring the transfer opportunity of the packet to the receiving station, the management unit requests the access point to ensure the transfer opportunity, and the management unit receives information regarding the ensured transfer opportunity from the access point when the request to ensure the transfer opportunity is permitted.

7. When the transmitting station and the receiving station are located in a communicable area, and when the management unit secures the transfer opportunity of the packet to the receiving station, the management unit notifies information regarding the secured transfer opportunity to communication stations located in the communicable area including the transmitting station and the receiving station. The relay station according to claim 1 or 2.

8. An access point capable of wireless communication through the plurality of links with the relay station according to claim 1 or 2, and in response to a request from the relay station to secure the transfer opportunity of the packet to the receiving station, determines whether to permit a request to secure the transfer opportunity, and when permitting the request to secure the transfer opportunity, notifies information regarding the secured transfer opportunity to communication stations located in a communicable area including the relay station and the receiving station. The access point includes an AP side management unit.

Images