Wireless device, communication device, wireless control method, communication control method, and program

There is provided a wireless device configured to perform both multi-user spatial multiplex communication and single user communication with a communication device. The wireless device is configured to set a first waiting time for the single user communication, and count the first waiting time in a period in which a second waiting time for the multi-user spatial multiplex communication is counted. The wireless device then transmits data through the single user communication after the first waiting time expires.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage Application based on PCT/JP2017/029872, filed Aug. 22, 2017, and claims the benefit of Japanese Priority Patent Application JP 2016-172716, filed Sep. 5, 2016, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a wireless device, a communication device, a wireless control method, a communication control method, and a program.

BACKGROUND ART

In recent years, standardization of a new wireless LAN has been under review by IEEE 802.11 working groups and the like. For example, a method in which a plurality of wireless devices simultaneously perform data transmission with one access point device using multi-user spatial multiplex communication is under review. Patent Literature 1 discloses a communication control method in a wireless device that performs both multi-user spatial multiplex communication and single user communication.

CITATION LIST

Patent Literature

SUMMARY

Technical Problem

However, in the wireless LAN system, implementation of the single user communication is delayed due to influence of implementation of the multi-user spatial multiplex communication. For example, when an operation mode is switched from the multi-user spatial multiplex communication to the single user communication, an initial value of a waiting time for the single user communication is reset. For this reason, even when data with high priority is transmitted, a wireless device is on standby until the reset waiting time elapses and performs data transmission using the single user communication after the waiting time elapses.

In this regard, the present disclosure was made in light of the foregoing, and provides a wireless device, a communication device, a wireless control method, a communication control method, and a program, which are novel and improved and capable of preventing the implementation of the single user communication from being delayed due to the influence of the implementation of the multi-user spatial multiplex communication in the wireless device that performs both the multi-user spatial multiplex communication and the single user communication.

Solution to Problem

According to an embodiment of the present disclosure, there is provided a wireless device, including circuitry configured to perform multi-user spatial multiplex communication and single-user communication with a communication device; set a first waiting time for the multi-user spatial multiplex communication and a second waiting time for the single user communication; transmit data to the communication device by the multi-user spatial multiplex communication in accordance with the first waiting time; count the second waiting time in a period during which the first waiting time for the multi-user spatial multiplex communication is counted after transmission of the data; and retransmit the data to the communication device by single-user communication according to the second waiting time in a case it is determined that an error occurred during the transmission of the data by the multi-user spatial multiplex communication.

Further, according to an embodiment of the present disclosure, there is provided a method performed by a wireless device, the method including: performing multi-user spatial multiplex communication and single user communication with a communication device; setting a first waiting time for the multi-user spatial multiplex communication and a second waiting time for the single user communication; transmitting data to the communication device by the multi-user spatial multiplex communication in accordance with the first waiting time; counting the second waiting time in a period during which the first waiting time for the multi-user spatial multiplex communication is counted after transmission of the data; and retransmitting the data to the communication device by single-user communication according to the second waiting time in a case it is determined that an error occurred during the transmission of the data by the multi-used spatial multiplex communication.

Further, according to an embodiment of the present disclosure, there is provided a non-transitory computer-readable medium including computer-program instructions, which when executed by a wireless device, cause the wireless device to: perform multi-user spatial multiplex communication and single-user communication with a communication device; set a first waiting time for the multi-user spatial multiplex communication and a second waiting time for the single user communication; transmit data to the communication device by the multi-user spatial multiplex communication in accordance with the first waiting time; count the second waiting time in a period during which the first waiting time for the multi-user spatial multiplex communication is counted after transmission of the data; and retransmit the data to the communication device by single-user communication according to the second waiting time in a case it is determined that an error occurred during the transmission of the data by the multi-used spatial multiplex communication.

Further, according to an embodiment of the present disclosure, there is provided a communication device, including: circuitry configured to perform multi-user spatial multiplex communication and single user communication with a wireless device; set a first waiting time for the single user communication and a second waiting time for the multi-user spatial multiplex communication; count the second waiting time in a period in which a first waiting time for the single user communication is counted after performing single user communication with the wireless device; and transmit a trigger frame including permission information for the multi-user spatial multiplex communication to the wireless device after the second waiting time expires.

Further, according to an embodiment of the present disclosure, there is provided a method performed by a communication device, the method including: performing multi-user spatial multiplex communication and single user communication with a wireless device; setting a first waiting time for the single user communication and a second waiting time for the multi-user spatial multiplex communication; counting the second waiting time in a period in which a first waiting time for the single user communication is counted after performing single user communication with the wireless device; and transmitting a trigger frame including permission information for the multi-user spatial multiplex communication to the wireless device after the second waiting time expires.

Further, according to an embodiment of the present disclosure, there is provided a non-transitory computer-readable medium including computer-program instructions, which when executed by a wireless device, cause the wireless device to: perform multi-user spatial multiplex communication and single user communication with a wireless device; set a first waiting time for the single user communication and a second waiting time for the multi-user spatial multiplex communication: count the second waiting time in a period in which a first waiting time for the single user communication is counted after performing single user communication with the wireless device; and transmit a trigger frame including permission information for the multi-user spatial multiplex communication to the wireless device after the second waiting time expires.

Advantageous Effects of Invention

As described above, according to an embodiment of the present disclosure, it is possible to prevent the implementation of the single user communication from being delayed due to the influence of the implementation of the multi-user spatial multiplex communication in the wireless device that performs both the multi-user spatial multiplex communication and the single user communication.

DESCRIPTION OF EMBODIMENTS

The description will proceed in the following order.

1. Overview of wireless LAN system

2. Configurations of devices

3. Operations of devices

4. Application examples

1. Overview of Wireless LAN System

An embodiment of the present disclosure relates to a wireless LAN system. First, an overview of a wireless LAN system according to an embodiment of the present disclosure will be described with reference toFIG. 1.

1-1. Configuration of Wireless LAN System

FIG. 1is a diagram illustrating a configuration of the wireless LAN system according to an embodiment of the present disclosure. As illustrated inFIG. 1, the wireless LAN system according to an embodiment of the present disclosure includes an access point device (hereinafter referred to as an “access point (AP)” for convenience)200and a station device (hereinafter referred to as a “station (STA)” for convenience)100. A basic service set (hereinafter referred to as a “BSS” for convenience)10is configured with one AP200and one or more STAs100.

The wireless LAN system according to an embodiment of the present disclosure can be installed in any place. For example, the wireless LAN system according to the present embodiment may be installed in an office building, a residential area, a commercial facility, a public facility, or the like. The BSS10may be arranged so that an area of the BSS10overlaps areas of other BSSs10.

The AP200according to the present embodiment functions as a communication device, is connected to an external network, and provides the STA100with communication with an external network. For example, the AP200is connected to the Internet and provides communication between the STA100and a device on the Internet or a device connected via the Internet.

Further, the AP200receives data using uplink multicast-user spatial multiplex communication (hereinafter referred to as “uplink multi-user (UL MU)” for convenience) or uplink single user communication (hereinafter referred to as “uplink single-user (UL SL)” for convenience).

To describe data reception using the UL MU in more detail, the AP200decides the STA100that executes the UL MU. Thereafter, the AP200generates a trigger frame (hereinafter referred to as “trigger” for convenience) including information related to the STA100which is permitted to perform the UL MU, information related to a period of time in which data transmission using the UL MU is performed, and the like (hereinafter referred to as “UL MU permission information” for convenience). Then, the AP200sets the waiting time before trigger transmission, and transmits the trigger to the STA100after the waiting time elapses, so that the STA100is allowed to perform the UL MU. The data reception by the AP200using the UL MU or the UL SU will be described later in detail.

The STA100according to the present embodiment is a wireless device that functions as a wireless device and communicates with the AP200. The STA100may be any wireless device. For example, the STA100may be a smartphone including a display having a display function, a memory having a storage function, a keyboard and a mouse having an input function, a speaker having an audio output function, and a function of executing an advanced calculation process.

The STA100according to the present embodiment performs data transmission to the AP200using the UL MU or the UL SU. To describe the data transmission using the UL MU specifically, the STA100receives the trigger from the AP200, and when its own STA100is included in the UL MU permission information included in the trigger, the STA100performs the data transmission to the AP200using the UL MU. In other words, the data transmission is performed to the AP200together with the STA100that is permitted to perform the UL MU other than its own STA. The data transmission by the STA100using the UL MU will be described later in detail.

Further, to describe the data transmission using the UL SU specifically, the STA100sets the waiting time before the UL SU on the basis of a priority of the transmission data, and after the waiting time has elapsed, the STA100performs the data transmission to the AP200using the UL SU. In other words, the STA100can perform the data transmission to the AP200using the UL SU without receiving the trigger of the UL MU. The data transmission by the STA100using the UL SU will be described later in detail.

In recent years, standardization of a new wireless LAN has been under review by IEEE 802.11 working groups and the like. Such review has included review for improving a communication control method using the UL MU and the UL SU in a method of a related art while securing compatibility with the method of the related art.

As the communication control method using the UL MU and the UL SU, for example, there is a disclosure of the related art 1. In this regard, content of the disclosure of the related art 1 will be described with reference toFIG. 2.FIG. 2is a diagram illustrating communication between an AP and an STA in the disclosure of the related art 1. As illustrated inFIG. 2, for example, there is a wireless LAN system including one AP and three STAs (STAs1to3).

First, in step S1000, the AP transmits a polling frame including information related to permission of the UL MU to each of the STAs. Here, the information related to the permission of the UL MU included in the polling refers to information related to an STA which executes the UL MU, a period of time for performing the UL MU (transmission opportunity (TXOP)), and the like. Each STA receives the polling frame, and checks the information related to the permission of the UL MU included in the polling frame. In steps S1004to S1012, each STA transmits the data transmission to the AP using the UL MU during the period of time of the TXOP designated by the polling when its own STA is included as the STA that is permitted to perform the UL MU.

Thus, in the disclosure of the related art 1, the data transmission by each STA is controlled by the polling transmitted from the AP. Therefore, the STA is unable to perform random access control in accordance with the priority of the transmission data. In the disclosure of related art 1, in order to enable the transmission control according to the priority of the transmission data held in the STA, it is necessary for the AP to detect the priority of the transmission data held in the STA in advance, but it is not easy to realize this.

Further, immediately after the TXOP ends, when the AP transmits the polling and sets a new TXOP, the STA has no opportunity to autonomously perform the data transmission. Therefore, the feasibility of the data transmission according to the priority of transmission data by STA is further lowered.

Next, the background of the present disclosure from another point of view will be described. InFIG. 2, it is assumed that the data transmitted by the STA3in step S1012is not received by the AP for some reason. In step S1016, the AP that has received the data transmitted by STA1and STA2generates a Block-ACK frame (hereinafter referred to as a “BA” for convenience) and transmits the BA to the respective STAs. The BA is a response frame including information related to a reception state of the frame transmitted by each STA. Since information indicating that the data transmitted by the STA1and the STA2has been received by the AP is included in the BA, the STA1and the STA2that have received the BA can detect that the transmission data has been properly received by the AP.

On the other hand, since the BA does not include information indicating that the data transmitted by the STA3has been received by the AP, the STA3that has received the BA determines that the transmission data has not been correctly received by the AP, and attempts to retransmit the transmission data. At that time, in step S1020, the STA3resets a contention window (hereinafter referred to as a “CW” for convenience) and resets a backoff counter on the basis of the CW. Therefore, the STA3retransmits the data using the UL SU after an arbitration inter frame space (hereinafter referred to as an “AIFS” for convenience) elapses, and the reset backoff counter becomes 0.

As described above, in the disclosure of related art 1, since the CW and the backoff counter are reset for the data transmission by the UL SU, the data transmission by the UL SU may be delayed from a desired timing. In this case, when the priority of the transmission data is high such as when the transmission data is audio data, the transmission data is significantly influenced.

Next, the background of the present disclosure will be described with reference toFIG. 3.FIG. 3is a diagram illustrating communication between the AP and the STA.

As illustrated inFIG. 3, after the backoff counter set on the basis of the CW corresponding to three slots becomes 0 in step S1100, in step S1104, the AP transmits the trigger including the information related to the permission of the UL MU to each STA. Each STA receives the trigger and checks the information related to the permission of the UL MU included in the trigger. In steps S1108to S1116, each STA performs the data transmission to the AP using the UL MU during a period of time designated by the trigger when its own STA is included as the STA that is permitted to perform the UL MU.

InFIG. 3, it is assumed that the data transmitted by the STA3is not received by the AP for some reason. In step S1120, the AP that has received the data transmitted by the STA1and the STA2generates a Multi-Block-ACK frame (hereinafter referred to as an “M-BA” for convenience) and transmits the M-BA to each STA. The M-BA is a response frame including information related to a reception state of the frame transmitted from each STA using the UL MU.

Since the information indicating that the data transmitted by the STA1and the STA2has been received by the AP is included in the M-BA, the STA1and the STA2that have received the M-BA can detect that the transmission data has been properly received by the AP. On the other hand, since the M-BA does not include information indicating that the data transmitted by the STA3has been received by the AP, the STA3that has received the M-BA can detect that the transmission data has not been correctly received by the AP.

After the backoff counter set on the basis of the CW corresponding to three slots becomes 0 in step S1124, in step S1128, the AP retransmits the trigger to each STA. In steps S1132to S1140, each STA performs the data transmission to the AP using the UL MU during the period of time designated by the trigger when its own STA is included in the STA that is permitted to perform the UL MU. At this time, since the STA3detects that the previous transmission data has not been correctly received by the AP, the STA3retransmits the previous transmission data.

In step S1144, the AP that has received the data transmitted by the STAs1to3generates the M-BA and transmits the M-BA to each STA. InFIG. 3, it is assumed that the M-BA has not been received by the STA3for some reason. When the M-BA is unable to be received during a standby time for reception of the M-BA, the STA3determines that the transmission data has not been correctly received by the AP and attempts to retransmit the transmission data.

In step S1148, the STA3resets the CW (the CW is reset to a CW corresponding to six slots inFIG. 3), and resets the backoff counter on the basis of the CW. Then, after the IFS elapses and the re-set backoff counter becomes 0, in step S1152the STA3retransmits the data using the UL SU. When the data transmitted using the UL SU is correctly received by the AP, the AP generates a Single-Block-ACK frame (hereinafter referred to as an “S-BA” for convenience) and transmits the S-BA to the STA3. The S-BA is a response frame including information related to a reception state of the frame transmitted from each STA using the UL SU. Since information indicating that the data transmitted by the STA3has been received by the AP is included in the S-BA, the STA3that has received the S-BA can detect that the transmission data has been correctly received by the AP.

As described above, even in the method ofFIG. 3, the CW is reset for the data transmission using the UL SU, and the backoff counter is also reset on the basis of the CW, similarly to the disclosure of related art 1, and thus the data transmission by the UL SU may be delayed from a desired timing.

In this regard, the disclosures of the present case have devised the present disclosure in view of the above circumstances. An STA100of the wireless LAN system according to an embodiment of the present disclosure can perform the data transmission according to the priority of the transmission data using the UL SU regardless of the UL MU. In addition, the STA100does not reset the backoff counter when the data transmission using the UL SU is performed after the UL MU, and thus it is possible to prevent the data transmission from being delayed due to the resetting of the backoff counter. In other words, the STA100can prevent the implementation of the UL SU from being delayed due to the implementation of the UL MU. The STA100and the AP200according to the present embodiment have compatibility with the STA and the AP employing the method of the related art. For example, the STA100and the AP200according to the present embodiment can correctly communicate with both the STA and the AP that perform random access control based on CSMA/CA using the method of the related art.

1-3. Function Overview of Wireless LAN System

The background of the present disclosure has been described above. Next, a function overview of the wireless LAN system according to an embodiment of the present disclosure will be described with reference toFIGS. 4 and 5.FIGS. 4 and 5are diagrams illustrating communication between the AP200and the STA100according to the present embodiment.

Steps S1200to S1244inFIG. 4are the same as the steps S1100to S1144inFIG. 3, and thus description thereof is omitted. In steps S1248and S1252, an STA100caccording to the present embodiment decreases a UL SU backoff counter during a period in which the AP200decreases a UL MU backoff counter in steps S1200and S1224.

Here, the backoff counter is set in accordance with the priority which is decided in accordance with an access category of transmission data (hereinafter referred to as an “access category (AC)” for convenience). Specifically, as the priority decided in accordance with the AC of the transmission data increases, the backoff counter decreases. In other words, as the priority of transmission data increases, the waiting time of the data transmission using the UL SU decreases. Further, when the trigger transmitted from the AP200is received, the STA100csuspends the decreasing of the UL SU backoff counter.

When the M-BA is unable to be received in step S1244, the STA100cdetermines that the transmission data has not been correctly received by the AP200and attempts to retransmit the transmission data. In this case, in step S1256, the STA100ccontinues to decrease the backoff counter that has already been decreased without resetting the CW and the backoff counter. Then, after the UL SU backoff counter becomes 0, in step S1260, the STA100cretransmits the data using the UL SU. Although not illustrated, when the UL SU backoff counter becomes 0 before the trigger transmission by the AP200, the STA100cperforms the data transmission to the AP200using the UL SU before the trigger transmission by the AP200.

As described above, the STA100of the wireless LAN system according to the present embodiment can perform the data transmission according to the priority of the transmission data using the UL SU regardless of the UL MU. Further, since the STA100does not reset the backoff counter when the data transmission using the UL SU is performed after the UL MU, it is possible to prevent the data transmission from being delayed due to the resetting of the backoff counter. In other words, the STA100can prevent the implementation of the UL SU from being delayed due to the implementation of the UL MU. The STA100and the AP200according to the present embodiment have compatibility with the STA and the AP employing the method of the related art. For example, the STA100and the AP200according to the present embodiment can correctly communicate with both the STA and the AP that perform random access control based on CSMA/CA using the method of the related art.

Next, communication between the AP200and the STA100in a case different from that inFIG. 4will be described with reference toFIG. 5.FIG. 5is a diagram illustrating an operation in which the STA100cperforms the UL SU when the STA100cis not included as the STA100that is permitted to perform the UL MU.

As illustrated inFIG. 5, in step S1300, the AP200decreases the backoff counter set based on the CW corresponding to three slots. Then, similarly toFIG. 4, in step S1308, the STA100cdecreases the UL SU backoff counter during a period in which the UL MU backoff counter is decreased by the AP200.

After the UL MU backoff counter becomes 0, in step S1304, the AP200transmits the trigger including the UL MU permission information to each STA100. Each STA100receives the trigger, and checks the UL MU permission information included in the trigger. In steps S1312to S1316, an STA100aand an STA100bcheck that they, the STAs, themselves are included as the STA100that is permitted to perform the UL MU, and perform the data transmission to the AP200using the UL MU during a period of time designated by the trigger.

In step S1320, the STA100csuspends the decreasing of the UL SU backoff counter at a timing at which the trigger is detected, checks that it, the STA, itself is not included as the STA100that is allowed to perform the UL MU, and sets a transmission prohibition period (hereinafter referred to as a “network allocation vector (NAV)” for convenience). The STA100cis unable to transmit a signal during a period in which the NAV is set.

In step S1324, the AP200that has received the data transmitted by the STA100aand the STA100bgenerates the M-BA and transmits the M-BA to each STA100. Thereafter, in step S1328, the AP200starts to decrease the UL MU backoff counter. The STA100cthat has received the M-BA detects that the UL MU has been completed and cancels the NAV. Then, in step S1332, the STA100crestarts decrease of the UL SU backoff counter which has been suspended.

Then, after the UL SU backoff counter becomes 0, in step S1336, the STA100cperforms the data transmission to the AP200using the UL SU. Upon receiving the data transmitted by the SA100c, the AP200suspends the decreasing of the UL MU backoff counter. Then, when the data transmitted using the UL SU is correctly received by the AP200, the AP200transmits the S-BA to the STA100. Thereafter, in step S1344, the AP200restarts the decreasing of the UL MU backoff counter that has been suspended. Steps S1344to S1364are the same as the steps S1304to S1324, and thus description thereof is omitted.

As described above, the STA100according to the present embodiment can perform the data transmission according to the priority of the transmission data using the UL SU regardless of the UL MU. In other words, the STA100can prevent the implementation of the UL SU from being delayed due to the implementation of the UL MU. The STA100and the AP200according to the present embodiment have compatibility with the STA and the AP employing the method of the related art. For example, the STA100and the AP200according to the present embodiment can correctly communicate with both the STA and the AP that perform random access control based on CSMA/CA using the method of the related art.

2. Configurations of Devices

2-1. Structure of STA

The function overview of the wireless LAN system according to an embodiment of the present disclosure has been described above. Next, a configuration of the STA100according to the present embodiment will be described with reference toFIG. 6.

FIG. 6is a diagram illustrating a configuration of the STA100according to an embodiment of the present disclosure. As illustrated inFIG. 6, the STA100includes a wireless communication unit110, a data processing unit120, and a control unit130.

As illustrated inFIG. 6, the wireless communication unit110includes an antenna control unit111, a reception processing unit112, and a transmission processing unit113. The wireless communication unit110functions as a communication unit.

The antenna control unit111controls transmission and reception of a signal via at least one antenna. More specifically, the antenna control unit111provides a signal received via the antenna to the reception processing unit112, and transmits a signal generated by the transmission processing unit113via the antenna.

The reception processing unit112performs a reception process on frames on the basis of the signal provided from the antenna control unit111. For example, the reception processing unit112performs an analog process and down-conversion on the signal obtained from the antenna, and outputs a baseband reception signal. Then, the reception processing unit112calculates a correlation between one or two or more signal patterns and the reception signal while shifting the reception signal to be operated on a time axis, and detects a preamble on the basis of the appearance of a correlation peak. Accordingly, the reception processing unit112can detect the trigger, the M-BA, the S-BA, the data frame, and the like which are transmitted by the AP200. Further, the reception processing unit112acquires the frames by performing demodulation, decoding, and the like on the baseband reception signal, and provides the acquired frames to a received frame analyzing unit121. Further, the reception processing unit112provides information related to the success or failure of the frame acquisition to a transmission control unit132.

The transmission processing unit113performs a process of transmitting the frame provided from a transmission frame constructing unit125. More specifically, the transmission processing unit113generates a signal to be transmitted on the basis of the frame provided from the transmission frame constructing unit125and a parameter set according to an instruction given from the transmission control unit132. For example, the transmission processing unit113generates a baseband transmission signal by performing encoding, interleaving, and modulation on the frame provided from the transmission frame constructing unit125in accordance with a coding and modulation scheme or the like instructed by the transmission control unit132. Further, the transmission processing unit113upconverts the baseband transmission signal obtained through the process of a preceding stage.

As illustrated inFIG. 6, the data processing unit120includes the received frame analyzing unit121, a receiving buffer122, an interface unit123, a transmitting buffer124, and a transmission frame constructing unit125.

The received frame analyzing unit121analyzes a received frame. More specifically, the received frame analyzing unit121acquires a type (the trigger, the M-BA, the S-BA, the data frame, or the like), a destination, and a transmission source of a frame received by the wireless communication unit110and data or control information included in the frame. For example, the received frame analyzing unit121acquires data or the like included in the received frame by performing analysis of a header, detection and correction of a code error, a reordering process, and the like on the received frame.

Further, when the trigger transmitted by the AP200is received, the received frame analyzing unit121acquires the UL MU permission information included in the trigger. Then, when its own STA is included as the STA100that is permitted to perform the UL MU, the received frame analyzing unit121provides information indicating that its own STA is included as the STA100that is permitted to perform the UL MU and information used for implementation of the UL MU (a period of time in which the data transmission using the UL MU is performed, information related to a frame length in the UL MU, or the like) to the transmission control unit132. Further, when the M-BA or the S-BA transmitted by the AP200is received, the received frame analyzing unit121acquires transmission data reception result information included in the M-BA or the S-BA, and transmits the information to the transmission control unit132.

The receiving buffer122stores received data. More specifically, the receiving buffer122stores data included in the received frame.

The interface unit123is an interface that is connected with other components installed in the STA100. More specifically, the interface unit123performs reception of data that is desired to be transmitted from the other components, for example, an application, a user interface, provision of received data to an application or a user interface, or the like.

The transmitting buffer124stores transmission data. More specifically, the transmitting buffer124stores the transmission data obtained through the interface unit123so that the transmission data is distinguished for each AC.

The transmission frame constructing unit125generates a frame to be transmitted. More specifically, the transmission frame constructing unit125generates a frame on the basis of the transmission data stored in the transmitting buffer124or the control information set by the control unit130. For example, the transmission frame constructing unit125generates a frame (packet) from the transmission data acquired from the transmitting buffer124and performs a process such as addition of a media access control (MAC) header for MAC and addition of an error detection code to the generated frame.

As illustrated inFIG. 6, the control unit130includes a CW processing unit131and the transmission control unit132.

The CW processing unit131functions as a setting unit, decides the CW in accordance with the priority of the AC of the transmission data, and sets the UL SU backoff counter on the basis of the CW. More specifically, the CW processing unit131sets the CW such that the CW decreases as the priority of the AC increases, and acquires a backoff counter which is a random number between 0 and the CW using the CW.

Then, the CW processing unit131decreases the UL SU backoff counter. More specifically, as long as a transmission path is detected to be in an idle state, the CW processing unit131decreases the UL SU backoff counter by one during the period in which the AP200decreases the UL MU backoff counter.

Here, the STA100and the AP200are in synchronization with each other on the basis of a reception timing of various kinds of frames (the trigger, the M-BA, the S-BA, and the like), and the CW processing unit131decreases the UL SU backoff counter in synchronization with the decreasing of the UL MU backoff counter by the AP200. For example, the CW processing unit131decreases the UL SU backoff counter in step S1248ofFIG. 4, and suspends the decreasing of the backoff counter when the trigger is received from the AP200in step S1204. Then, the CW processing unit131restarts the decreasing of the backoff counter at a timing at which the response frame (the M-BA or the like) is received from the AP200or at a timing at which a reception standby time for the response frame elapses.

Then, when the backoff counter corresponding to a certain AC becomes 0, the CW processing unit131sets a transmission enable flag for the AC. In other words, the transmission enable flag is set for each AC, and an AC in which the data transmission using the UL SU can be performed is determined on the basis of the transmission enable flag. Here, the period in which the backoff counter is decreased for the data transmission using the UL SU is referred to as a “first waiting time.”

As described above, as the priority of the AC increases, the CW decreases, and thus the backoff counter which is a random number between 0 and the CW decreases. In other words, as the priority of the transmission data increases, the waiting time of the data transmission using the UL SU decreases.

Here, the type of the AC and the priority of the AC will be described with reference toFIG. 8.FIG. 8is a diagram illustrating the type of the AC and the priority of the AC. As illustrated inFIG. 8, in IEEE802.11, the AC is classified into four types: AC_VO (Voice); AC_VI (Video); AC_BE (Best Effort); and AC_BK (Background). A priority is assigned to each of the four types of ACs. Specifically, as illustrated inFIG. 8, the priority of AC_VO is set to be highest, and the priority of AC_BK is set to be lowest. Then, priority control is implemented by deciding the data transmission interval (the AIFS or the like) or a setting range of the CW in accordance with the priority for each AC.

The transmission control unit132controls the data transmission. For example, the transmission control unit132controls transmission of signals using the UL SU or the UL MU. To describe the data transmission using the UL SU more specifically, when the transmission data is stored in the transmitting buffer124, the transmission control unit132instructs the transmission frame constructing unit125to generate a frame in which the transmission data is stored. Then, the transmission control unit132instructs the CW processing unit131to set the backoff counter and decrease the backoff counter. Thereafter, when information indicating that the backoff counter becomes 0 (that is, the transmission enable flag of a certain AC is set) is provided from the CW processing unit131, the transmission control unit132instructs the transmission processing unit113to perform the data transmission using the UL SU.

Further, to describe the data transmission using the UL MU more specifically, when the transmission data is stored in the transmitting buffer124, the transmission control unit132instructs the transmission frame constructing unit125to generate a frame in which the transmission data is stored. When information indicating that its own STA is included as the STA100that is permitted to perform the UL MU is provided from the received frame analyzing unit121, the transmission control unit132instructs the transmission processing unit113to perform the data transmission using the UL MU.

2-2. Structure of AP

The configuration of the STA100has been described above. Next, a configuration of the AP200will be described with reference toFIG. 7.

FIG. 7is a diagram illustrating the configuration of the AP200according to an embodiment of the present disclosure. As illustrated inFIG. 7, the AP200may have the same configuration as the STA100illustrated inFIG. 6. It will be appreciated that the AP200may be configured to include a component which is not installed in the STA100. In the following description, description of components having the same functions as those of the STA100will be omitted.

As illustrated inFIG. 7, a wireless communication unit210includes an antenna control unit211, a reception processing unit212, and a transmission processing unit213. The wireless communication unit210functions as a communication unit. Since the reception processing unit212and the transmission processing unit213have the same functions as those in the wireless communication unit110of the STA100, description thereof is omitted.

The antenna control unit211can perform space division multiplex communication by controlling transmission and reception of signals via a plurality of antennas. The number of antennas is arbitrary. Since the other functions of the antenna control unit211are the same as those of the antenna control unit111of the STA100, description thereof is omitted.

As illustrated inFIG. 7, a data processing unit220includes a received frame analyzing unit221, a receiving buffer222, an interface unit223, a transmitting buffer224, and a transmission frame constructing unit225. Since the received frame analyzing unit221, the receiving buffer222, the interface unit223, and the transmitting buffer224have the same functions as those in the data processing unit120of the STA100, description thereof is omitted.

The transmission frame constructing unit225is controlled by the transmission control unit232and generates the trigger, the M-BA or the S-BA. For example, the transmission frame constructing unit225generates the trigger including the UL MU permission information provided from the transmission control unit232. Further, the transmission frame constructing unit225generates the M-BA or the S-BA on the basis of the information related to the success or failure of the frame acquisition provided from the transmission control unit232. It will be appreciated that, similarly to the transmission frame constructing unit125of the STA100, the transmission frame constructing unit225may generate the frame including the transmission data stored in the transmitting buffer224.

As illustrated inFIG. 7, a control unit230includes a CW processing unit231and the transmission control unit232.

The CW processing unit231functions as a setting unit, decides the CW of the trigger for the UL MU, and sets the UL MU backoff counter on the basis of the CW. More specifically, the CW processing unit231decides the CW for transmitting the trigger including the UL MU permission information. Here, the CW processing unit231sets a CW smaller than the CW for the data transmission using the UL SU by the STA100as the CW of the trigger. Accordingly, since the UL MU backoff counter can be set to be smaller than the UL SU backoff counter, the trigger transmission for the UL MU can be performed preferentially over the data transmission using the UL SU by the STA100. It will be appreciated that the CW processing unit231may set the CW which is equal to or more than the CW for the data transmission using the UL SU as the CW of the trigger.

Then, the CW processing unit231decreases the UL MU backoff counter. More specifically, as long as the transmission path is detected to be in the idle state, the CW processing unit231decreases the backoff counter by one during the period in which the STA100decreases the UL SU backoff counter. Here, for example, the CW processing unit231decreases the UL MU backoff counter in step S1328inFIG. 5, and when the data transmitted from the STA100cusing the UL SU is received, the CW processing unit231suspends the decreasing of the backoff counter in step S1336. Then, after the S-BA is transmitted to the STA100cin step S1340, the CW processing unit231restarts the decreasing of the backoff counter in step S1344.

Then, when the backoff counter corresponding to a certain AC becomes 0, the trigger is able to be transmitted. Here, a period in which the backoff counter is decreased for the trigger transmission for the UL MU is referred to as a “second waiting time.” Since the other functions of the CW processing unit231are the same as those of the CW processing unit131of the STA100, description thereof is omitted.

The transmission control unit232controls the data transmission. For example, the transmission control unit232controls transmission of the trigger, the M-BA, the S-BA or the data frame. To describe the transmission control of the trigger more specifically, the transmission control unit232provides the UL MU permission information to the transmission frame constructing unit225and instructs the transmission frame constructing unit225to generate the trigger. Then, the transmission control unit232instructs the CW processing unit231to set the backoff counter and decrease the backoff counter. Thereafter, when the information indicating that the backoff counter has become 0 is provided from the CW processing unit231, the transmission control unit232instructs the transmission processing unit213to transmit the trigger.

Further, if the transmission control of the M-BA or the S-BA is described more specifically, when data is received in accordance with the UL MU or the UL SU, the transmission control unit232provides the information related to the success or failure of the frame acquisition to the transmission frame constructing unit225and instructs the transmission frame constructing unit225to generate the M-BA or the S-BA. Then, the transmission control unit232instructs the transmission processing unit213to transmit the M-BA or the S-BA.

3. Operations of Devices

The configuration of the AP200according to the present embodiment has been described above. Next, the data transmission operation by the STA100will be described with reference toFIGS. 9A and 9B.FIGS. 9A and 9Bare flowcharts illustrating the data transmission operation by the STA100.

First, when the transmission data is provided from the application or the user interface via the interface unit123in step S1400(Yes in step S1400), in step S1404, the transmission data is stored in the transmitting buffer124. In step S1408, the CW processing unit131acquires AC information of the transmission data, and in step S1412, the CW processing unit131decides the CW in accordance with the acquired priority of the AC and sets the backoff counter on the basis of the CW. When the transmission data is not provided in step S1400(No in step S1400), the process proceeds to step S1416.

Thereafter, when the wireless transmission path is in the idle state (Yes in step S1416), after a predetermined slot time period elapses (Yes in step S1420), in step S1424, the CW processing unit131decreases the backoff counter. When the wireless transmission path is not in the idle state in step S1416(No in step S1416), the process proceeds to step S1436. When the predetermined slot time period does not elapse in step S1420(No in step S1420), the process proceeds to step S1416.

When the backoff counter corresponding to a certain AC becomes 0 (Yes in step S1428), in step S1432, the CW processing unit131sets the transmission enable flag for the AC. When there is no AC in which the backoff counter is 0 in step S1428(No in step S1428), the process proceeds to step S1436.

Here, even when the backoff counter of a certain AC becomes 0, and the transmission enable flag is set for the AC, in step S1436, it is checked whether or not the trigger of the UL MU is received. Thus, when the trigger of the UL MU is received at a timing at which the backoff counter of a certain AC becomes 0, the data transmission by the UL MU can be performed preferentially over the data transmission by the UL SU.

When the wireless communication unit110receives the trigger from the AP200(Yes in step S1436), the received frame analyzing unit121acquires the UL MU permission information included in the trigger. Then, when its own STA is included as the STA100that is permitted to perform the UL MU (Yes in step S1444), the received frame analyzing unit121provides information indicating that its own STA is included as the STA100that is permitted to perform the UL MU and information used for implementation of the UL MU (a period of time in which the data transmission using the UL MU is performed, information related to a frame length in the UL MU, or the like) to the transmission control unit132. In step S1448, the transmission control unit132checks the presence or absence of the transmission data of each AC in the transmitting buffer124.

When there is transmission data (Yes in step S1448), in step S1452, the transmission control unit132instructs the transmission frame constructing unit125to generate a transmission frame. Then, after the transmission frame is generated, the transmission control unit132instructs the transmission processing unit113to perform the data transmission using the UL MU. At this time, the transmission control unit132provides the information used for the implementation of the UL MU to the transmission frame constructing unit125and the transmission processing unit113. When its own STA is not included as the STA100that is permitted to perform the UL MU in step S1444(No in step S1444), the NAV is set, and the process proceeds to step S1428.

After the data transmission using the UL MU, when the wireless communication unit110receives the M-BA from the AP200(Yes in step S1456), the received frame analyzing unit121acquires transmission data reception result information included in the M-BA. When information indicating that the transmission data has been correctly received by the AP200is included in the reception result information (step Yes in S1460), in step S1464, the transmission control unit132deletes the transmission data stored in the transmitting buffer124.

Then, when it is completely checked whether all data stored in the transmitting buffer124has been received (Yes in step S1468), the series of data transmission processes by the STA100is completed. When the wireless communication unit110does not receive the M-BA from the AP200in step S1456(No in step S1456), when information indicating that the transmission data has been received correctly in the AP200is not included in the reception result information in step S1460(No in step S1460), or when it is not completely checked whether all data stored in the transmitting buffer124has been received in step S1468(No in step S1468), the process proceeds to step S1400.

When the wireless communication unit110does not receive the trigger from the AP200in step S1436(No in step S1436), the transmission control unit132checks whether or not there is an AC in which the transmission enable flag is set. When there is an AC in which the transmission enable flag is set (step Yes in S1476), in step S1480, the transmission control unit132instructs the transmission frame constructing unit125to generate the transmission frame using the transmission data of the AC. After the transmission frame is generated, the transmission control unit132instructs the transmission processing unit113to transmit the data transmission using the UL SU.

Thereafter, when the wireless communication unit110receives the S-BA from the AP200(Yes in step S1484), the received frame analyzing unit121acquires transmission data reception result information included in the S-BA. When information indicating that the transmission data has been correctly received by the AP200is included in the reception result information (Yes in step S1488), the process proceeds to step S1464. When there is no AC in which the transmission enable flag is set in step S1476(step No in S1476), when the wireless communication unit110does not receive the S-BA from the AP200in step S1484(No in step S1484), or when the information indicating that the transmission data has been correctly received by the AP200is not included in the reception result information in step S1488(No in step S1488), the process proceeds to step S1400.

4. Application Examples

The data transmission operation by the STA100has been described above, and now application examples of the present disclosure will be described below.

The technology of the present disclosure can be applied to various products. For example, the STA100may be implemented as a mobile terminal such as a smartphone, a tablet personal computer (PC), a laptop PC, a portable game terminal, or a digital camera, a fixed terminal such as a television receiver, a printer, a digital scanner, or a network storage, or an in-vehicle terminal such as a car navigation apparatus. Further, the STA100may be implemented as a terminal that performs machine to machine (M2M) communication (also referred to as a “machine type communication (MTC) terminal”) such as a smart meter, a vending machine, a remote monitoring device, or a point of sale (POS) terminal. Further, the STA100may be a wireless communication module mounted on any such terminal (for example, an integrated circuit module configured with one die).

On the other hand, for example, the AP200may be implemented as a wireless LAN access point having a router function or having no router function (also referred to as a “wireless base station”). Further, the AP200may be implemented as a mobile wireless LAN router. Further, the AP200may be a wireless communication module mounted on any such device (for example, an integrated circuit module configured with one die).

4-1. First Application Example

FIG. 10is a block diagram showing an example of a schematic configuration of a smartphone900to which the technology of the present disclosure can be applied. The smartphone900includes a processor901, a memory902, a storage903, an externally connected interface904, a camera906, a sensor907, a microphone908, a input device909, a display device910, a speaker911, a wireless communication interface913, an antenna switch914, an antenna915, a bus917, a battery918, and an auxiliary controller919.

The processor901may be, for example, a central processing unit (CPU) or a system on chip (SoC), and controls functions of an application layer and other layers of the smartphone900. The memory902includes a random access memory (RAM) and a read only memory (ROM), and stores programs executed by the processor901and data. The storage903can include a storage medium such as a semiconductor memory or a hard disk. The externally connected interface904is an interface for connecting an externally attached device such as a memory card or a universal serial bus (USB) device to the smartphone900.

The camera906has an image sensor, for example, a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) to generate captured images. The sensor907can include a sensor group including, for example, a positioning sensor, a gyro sensor, a geomagnetic sensor, an acceleration sensor, and the like. The microphone908converts sounds input to the smartphone900into audio signals. The input device909includes, for example, a touch sensor that detects touches on a screen of the display device910, a key pad, a keyboard, buttons, switches, and the like to receive manipulations or information inputs from a user. The display device910has a screen such as a liquid crystal display (LCD), or an organic light emitting diode (OLED) display to display output images of the smartphone900. The speaker911converts audio signals output from the smartphone900into sounds.

The wireless communication interface913supports one or more wireless LAN standards of IEEE 802.11a, 11b, 11g, 11n, 11ac, and 11ad to execute wireless LAN communication. The wireless communication interface913can communicate with another apparatus via a wireless LAN access point in the infrastructure mode. In addition, the wireless communication interface913can directly communicate with another apparatus in a direct communication mode, such as an ad hoc mode, Wi-Fi Direct, or the like. In Wi-Fi Direct (registered trademark), one of two terminals operates as an access point unlike in an ad hoc mode, but communication is performed directly between the terminals. The wireless communication interface913can typically have a baseband processor, an radio frequency (RF) circuit, a power amplifier, and the like. The wireless communication interface913may be a single-chip module on which a memory that stores a communication control program, a processor that executes the program, and a relevant circuit are integrated. The wireless communication interface913may support another kind of wireless communication scheme such as a short-range wireless communication scheme, a proximity wireless communication scheme, or the cellular communication scheme in addition to the wireless LAN scheme. The antenna switch914switches a connection destination of the antenna915for a plurality of circuits (for example, a circuit for another wireless communication scheme) included in the wireless communication interface913. The antenna915has a single or a plurality of antenna elements (for example, a plurality of antenna elements included in a MIMO antenna) and is used for transmission and reception of wireless signals from the wireless communication interface913.

Note that the smartphone900may include a plurality of antennas (for example, antennas for a wireless LAN or antennas for a proximity wireless communication scheme, or the like), without being limited to the example ofFIG. 10. In this case, the antenna switch914may be omitted from the configuration of the smartphone900.

The bus917connects the processor901, the memory902, the storage903, the externally connected interface904, the camera906, the sensor907, the microphone908, the input device909, the display device910, the speaker911, the wireless communication interface913, and the auxiliary controller919to one another. The battery918supplies electric power to each of the blocks of the smartphone900shown inFIG. 10via power supply lines partially indicated by dashed lines in the drawing. The auxiliary controller919causes, for example, required minimum functions of the smartphone900to be operated in a sleep mode.

The wireless communication unit110, the data processing unit120, and the control unit130described with reference toFIG. 6in the smartphone900shown inFIG. 10may be mounted on the wireless communication interface913. At least some of the functions may be mounted on the processor901or the auxiliary controller919.

The smartphone900may operate as a wireless access point (software AP) when the processor901performs an access point function at an application level. The wireless communication interface913may have the wireless access point function.

4-2. Second Application Example

FIG. 11is a block diagram showing an example of a schematic configuration of a car navigation apparatus920to which the technology of the present disclosure can be applied. The car navigation apparatus920includes a processor921, a memory922, a global positioning system (GPS) module924, a sensor925, a data interface926, a content player927, a storage medium interface928, an input device929, a display device930, a speaker931, a wireless communication interface933, an antenna switch934, an antenna935, and a battery938.

The processor921may be, for example, a CPU or an SoC controlling a navigation function and other functions of the car navigation apparatus920. The memory922includes a RAM and a ROM storing programs executed by the processor921and data.

The GPS module924measures a position of the car navigation apparatus920(for example, latitude, longitude, and altitude) using GPS signals received from a GPS satellite. The sensor925can include a sensor group including, for example, a gyro sensor, a geomagnetic sensor, a barometric sensor, and the like. The data interface926is connected to an in-vehicle network941via, for example, a terminal that is not illustrated to acquire data generated on the vehicle side such as car speed data.

The content player927reproduces content stored in a storage medium (for example, a CD or a DVD) inserted into the storage medium interface928. The input device929includes, for example, a touch sensor that detects touches on a screen of the display device930, buttons, switches, and the like to receive manipulations or information inputs from a user. The display device930has a screen such as an LCD or an OLED display to display images of the navigation function or reproduced content. The speaker931outputs sounds of the navigation function or reproduced content.

The wireless communication interface933supports one or more wireless LAN standards of IEEE 802.11a, 11b, 11g, 11n, 11ac, and 11ad to execute wireless LAN communication. The wireless communication interface933can communicate with another apparatus via a wireless LAN access point in the infrastructure mode. In addition, the wireless communication interface933can directly communicate with another apparatus in a direct communication mode, such as an ad hoc mode, Wi-Fi Direct, or the like. The wireless communication interface933can typically have a baseband processor, an RF circuit, a power amplifier, and the like. The wireless communication interface933may be a single-chip module on which a memory that stores a communication control program, a processor that executes the program, and a relevant circuit are integrated. The wireless communication interface933may support another kind of wireless communication scheme such as a short-range wireless communication scheme, a proximity wireless communication scheme, or the cellular communication scheme in addition to the wireless LAN scheme. The antenna switch934switches a connection destination of the antenna935for a plurality of circuits included in the wireless communication interface933. The antenna935has a single or a plurality of antenna elements and is used for transmission and reception of wireless signals from the wireless communication interface933.

Note that the car navigation apparatus920may include a plurality of antennas, without being limited to the example ofFIG. 11. In this case, the antenna switch934may be omitted from the configuration of the car navigation apparatus920.

The battery938supplies electric power to each of the blocks of the car navigation apparatus920shown inFIG. 11via power supply lines partially indicated by dashed lines in the drawing. In addition, the battery938accumulates electric power supplied from the vehicle.

The wireless communication unit110, the data processing unit120, and the control unit130described with reference toFIG. 6in the car navigation apparatus920shown inFIG. 11may be mounted on the wireless communication interface933. At least some of the functions may be mounted on the processor921.

Further, the wireless communication interface933may operate as the above-described AP200and may provide wireless connection to a terminal carried by a user getting in a vehicle.

Further, the technology of the present disclosure may be realized as an in-vehicle system (or a vehicle)940including one or more blocks of the above-described car navigation apparatus920, the in-vehicle network941, and a vehicle-side module942. The vehicle-side module942generates vehicle-side data such as a vehicle speed, the number of engine rotations, or failure information and outputs the generated data to the in-vehicle network941.

4-3. Third Application Example

FIG. 12is a block diagram showing an example of a schematic configuration of a wireless access point950to which the technology of the present disclosure can be applied. The wireless access point950includes a controller951, a memory952, an input device954, a display device955, a network interface957, a wireless communication interface963, an antenna switch964, and an antenna965.

The controller951may be, for example, a CPU or a digital signal processor (DSP) and operates various functions (for example, access restriction, routing, encryption, firewall, and log management) of the Internet Protocol (IP) layer and higher layers of the wireless access point950. The memory952includes a RAM and a ROM and stores a program to be executed by the controller951and various kinds of control data (for example, a terminal list, a routing table, an encryption key, security setting, and a log).

The input device954includes, for example, buttons or switches and receives manipulations from a user. The display device955includes an LED lamp or the like and displays operation status of the wireless access point950.

The network interface957is a wired communication interface that connects the wireless access point950to a wired communication network958. The network interface957may include a plurality of connection terminals. The wired communication network958may be a LAN such as Ethernet (registered trademark) or a wide area network (WAN).

The wireless communication interface963supports one or more wireless LAN standards of IEEE 802.11a, 11b, 11g, 11n, 11ac, and 11ad to provide a wireless connection to a terminal located nearby as an access point. The wireless communication interface963can typically have a baseband processor, an RF circuit, a power amplifier, and the like. The wireless communication interface963may be a single-chip module on which a memory that stores a communication control program, a processor that executes the program, and a relevant circuit are integrated. The antenna switch964switches a connection destination of the antenna965for a plurality of circuits included in the wireless communication interface963. The antenna965has a single antenna element or a plurality of antenna elements and is used for transmission and reception of wireless signals from the wireless communication interface963.

The wireless communication unit210, the data processing unit220, and the control unit230described with reference toFIG. 7in the wireless access point950shown inFIG. 12may be mounted on the wireless communication interface963. At least some of the functions may be mounted on the controller951.

As described above, in the present embodiment, the STA100can perform the data transmission according to the priority of the transmission data using the UL SU regardless of the UL MU. In addition, the STA100does not reset the backoff counter when the data transmission using the UL SU is performed after the UL MU, and thus it is possible to prevent the data transmission from being delayed due to the resetting of the backoff counter. In other words, the STA100can prevent the implementation of the UL SU from being delayed due to the implementation of the UL MU. The STA100and the AP200according to the present embodiment have compatibility with the STA and the AP employing the method of the related art. For example, the STA100and the AP200according to the present embodiment can correctly communicate with both the STA and the AP that perform random access control based on CSMA/CA using the method of the related art.

For example, steps in the operation of the STA100according to the present embodiment need not necessarily be performed chronologically in accordance with the order described in the flowcharts. For example, steps in the process of the STA100may be performed in an order different from the order described in the flowcharts or may be performed in parallel.

Further, some components of the STA100may be appropriately installed outside the STA100. Similarly, some components of the AP200may be appropriately installed outside the AP200.

Further, some functions of the STA100may be implemented by the control unit130. In other words, the control unit130may implement some functions of the wireless communication unit110or the data processing unit120. Similarly, some functions of the AP200may be implemented by the control unit230. In other words, the control unit230may implement some functions of the wireless communication unit210or the data processing unit220.

Further, the effects described in this specification are merely illustrative or exemplified effects, and are not limitative. That is, with or in the place of the above effects, the technology according to an embodiment of the present disclosure may achieve other effects that are clear to those skilled in the art from the description of this specification.

(1) A wireless device, including

circuitry configured to

perform multi-user spatial multiplex communication and single-user communication with a communication device;

set a first waiting time for the multi-user spatial multiplex communication and a second waiting time for the single user communication;

transmit data to the communication device by the multi-user spatial multiplex communication in accordance with the first waiting time;

count the second waiting time in a period during which the first waiting time for the multi-user spatial multiplex communication is counted after transmission of the data; and

retransmit the data to the communication device by single-user communication according to the second waiting time in a case it is determined that an error occurred during the transmission of the data by the multi-user spatial multiplex communication.

(2) The wireless device according to (1), wherein

the circuitry is configured to count the first waiting time in synchronization with the second waiting time after transmission of the data.

(3) The wireless device according to any of (1) to (2), wherein the circuitry is configured to:

receive a trigger frame from the communication device; and

transmit the data using the multi-user spatial multiplex communication in a case where the wireless device is included as a permission target of the multi-user spatial multiplex communication designated by the trigger frame.

(4) The wireless device according to (3), wherein

the circuitry is configured to not reset the second waiting time which is being counted even after the data is transmitted using the multi-user spatial multiplex communication.

(5) The wireless device according to (3), wherein the circuitry is configured to:

suspend counting the second waiting time based on reception of the trigger frame; and

start reception of a response frame with respect to transmission of the data using the multi-user spatial multiplex communication or initiate counting of the second waiting time based on a lapse of a standby time for reception of the response frame.

(6) The wireless device according to any of (1) to (5), wherein

the circuitry is configured to set the second waiting time based on a priority of the data.

(7) The wireless device according to any of (1) to (6), wherein

the circuitry is configured to set the second waiting time to a time longer than the first waiting time.

(8) The wireless device according to (6), wherein

the communication device is an access point,

the wireless device is a station configured to communicate with the access point, the first waiting time and the second waiting time are backoff times that are set based on a contention window, and

the priority of the data is set in accordance with an access category.

(9) The wireless device according to any of (1) to (8), wherein

the multi-user spatial multiplex communication and the single user communication are uplink communications from the wireless device to the communication device.

(10) A method performed by a wireless device, the method including:

performing multi-user spatial multiplex communication and single user communication with a communication device;

setting a first waiting time for the multi-user spatial multiplex communication and a second waiting time for the single user communication;

transmitting data to the communication device by the multi-user spatial multiplex communication in accordance with the first waiting time;

counting the second waiting time in a period during which the first waiting time for the multi-user spatial multiplex communication is counted after transmission of the data; and

retransmitting the data to the communication device by single-user communication according to the second waiting time in a case it is determined that an error occurred during the transmission of the data by the multi-used spatial multiplex communication.

(11) A non-transitory computer-readable medium including computer-program instructions, which when executed by a wireless device, cause the wireless device to:

perform multi-user spatial multiplex communication and single-user communication with a communication device;

set a first waiting time for the multi-user spatial multiplex communication and a second waiting time for the single user communication;

transmit data to the communication device by the multi-user spatial multiplex communication in accordance with the first waiting time;

count the second waiting time in a period during which the first waiting time for the multi-user spatial multiplex communication is counted after transmission of the data; and

retransmit the data to the communication device by single-user communication according to the second waiting time in a case it is determined that an error occurred during the transmission of the data by the multi-used spatial multiplex communication.

circuitry configured to

perform multi-user spatial multiplex communication and single user communication with a wireless device;

set a first waiting time for the single user communication and a second waiting time for the multi-user spatial multiplex communication;

count the second waiting time in a period in which a first waiting time for the single user communication is counted after performing single user communication with the wireless device; and

transmit a trigger frame including permission information for the multi-user spatial multiplex communication to the wireless device after the second waiting time expires.

(13) The communication device according to (12), wherein the circuitry is configured to:

receive data from the wireless device through the multi-user spatial multiplex communication in response to the trigger frame;

generate a response frame for the multi-user spatial multiplex communication based on reception of the data through the multi-user spatial multiplex communication; and

transmit the response frame for the multi-user spatial multiplex communication to the wireless device.

(14) The communication device according to any of (12) to (13), wherein the circuitry is configured to:

receive data from the wireless device through the single user communication;

generate a response frame for the single user communication based on reception of the data through the single user communication; and

transmit the response frame for the single user communication to the wireless device.

(15) The communication device according to (14), wherein the circuitry is configured to:

suspend counting the second waiting time based on the reception of the data through the single user communication; and

start counting the second waiting time based on transmission of the response frame for the single user communication.

(16) The communication device according to any of (12) to (15), wherein

the communication device is an access point device,

the wireless device is a station device configured to communicate with the access point, and

the first waiting time and the second waiting time are backoff times that are set based on a contention window.

(17) The communication device according to any of (12) to (17), wherein

the multi-user spatial multiplex communication and the single user communication are uplink communications from the wireless device to the communication device.

(18) A method performed by a communication device, the method including:

performing multi-user spatial multiplex communication and single user communication with a wireless device;

setting a first waiting time for the single user communication and a second waiting time for the multi-user spatial multiplex communication;

counting the second waiting time in a period in which a first waiting time for the single user communication is counted after performing single user communication with the wireless device; and

transmitting a trigger frame including permission information for the multi-user spatial multiplex communication to the wireless device after the second waiting time expires.

(19) A non-transitory computer-readable medium including computer-program instructions, which when executed by a wireless device, cause the wireless device to:

perform multi-user spatial multiplex communication and single user communication with a wireless device;

set a first waiting time for the single user communication and a second waiting time for the multi-user spatial multiplex communication;

count the second waiting time in a period in which a first waiting time for the single user communication is counted after performing single user communication with the wireless device; and

transmit a trigger frame including permission information for the multi-user spatial multiplex communication to the wireless device after the second waiting time expires.

REFERENCE SIGNS LIST