# US 10,321,481 B2 · Wireless communication device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,321,481 B2 - Document ID: US10321481B2 - Status: Granted - Kind: B2 - Application number: 15/437,719 - Filed: 2017-02-21 - Published: 2017-06-15 - Granted: 2019-06-11 - Earliest claimed: 2014-11-18 - Assignees: Kabushiki Kaisha Toshiba - Applicants: Kabushiki Kaisha Toshiba - Inventors: Toshihisa Nabetani; Hiroki Mori - Web page: https://patentgrep.com/patent/US10321481B2 ## CPC - H04W 74/08: Non-scheduled access, e.g. ALOHA (hybrid access H04W74/02) - H04B 7/0413: MIMO systems - H04B 7/0452: Multi-user MIMO systems - H04B 7/0848: {Joint weighting} - H04W 4/08: User group management - H04W 8/186: {Processing of subscriber group data} - H04W 72/121: for groups of terminals or users - H04W 72/21: in the uplink direction of a wireless link, i.e. towards the network - H04W 74/002: {Transmission of channel access control information} - H04W 74/085: {collision avoidance} - H04W 74/0808: using carrier sensing, e.g. carrier sense multiple access [CSMA] - H04W 84/12: WLAN [Wireless Local Area Networks] - H04W 88/02: Terminal devices - H04W 88/08: Access point devices - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04B: TRANSMISSION ## Abstract According to one embodiment, a wireless communication device includes: controlling circuitry configured to determine parameter information on a backoff time of carrier sensing performed according to CSMA/CA (carrier sense multiple access/collision avoidance) on basis of a number of other wireless communication devices which have established connections with the wireless communication device; and a transmitter configured to transmit a first frame which instructs to transmit a response frame according to the parameter information. ## Claims ### Claim 1 A wireless communication device communicating with a plurality of other wireless communication devices comprising: controlling circuitry configured to select, from among the other wireless communication devices, first wireless communication devices for inquiring whether to have data for uplink multiuser multiplexing transmission and determine parameter information of a contention window used in CSMA/CA (carrier sense multiple access/collision avoidance) for the first wireless communication devices on basis of a number of the first wireless communication devices; a transmitter configured to transmit a first frame to the first wireless communication devices, wherein the first frame includes information to specify the first wireless communication devices and the parameter information, and the first frame instructs the first wireless communication devices to use the contention window based on the parameter information for acquisition of a transmission right for transmission of a response frame for the first frame; and a receiver configured to sequentially receive second frames transmitted based on the acquired transmission right from the first wireless communication devices in a single user manner wherein the second frames are response frames for the first frame and the transmission right is acquired under carrier sensing during a backoff time determined based on a value selected randomly from the contention window, wherein the controlling circuitry is configured to select second wireless communication devices for execution of uplink multiuser multiplexing transmission from among the first wireless communication devices which have transmitted the second frame. ### Claim 2 (depends on 1) The wireless communication device according to claim 1, wherein the parameter information defines a range of random numbers as the contention window, and the controlling circuitry is configured to determine the parameter information so as to increase the range of random numbers as the number of first wireless communication devices increases. ### Claim 3 (depends on 1) The wireless communication device according to claim 1, wherein the controlling circuitry is configured to determine the parameter information on basis of a number of wireless communication devices supporting an uplink multiuser multiplexing scheme among the first wireless communication devices. ### Claim 4 (depends on 1) The wireless communication device according to claim 1, wherein the controlling circuitry is configured to determine the parameter information on basis of a number of wireless communication devices that are not transited into a low power consumption mode among the first wireless communication devices. ### Claim 5 (depends on 1) The wireless communication device according to claim 1, wherein the transmitter is configured to transmit a fourth frame including information to specify the second wireless communication devices, and the receiver is configured to receive fifth frames transmitted in the uplink multiuser multiplexing from the second wireless communication devices a predetermined time after the fourth frame is transmitted. ### Claim 6 (depends on 5) The wireless communication device according to claim 5, wherein the transmitter is configured to transmit the fourth frame when a predetermined condition is satisfied after the first frame is transmitted. ### Claim 7 (depends on 6) The wireless communication device according to claim 6, wherein the transmitter is configured to transmit the fourth frame when at least any one of following cases is established as the predetermined condition: a case where a predetermined time limit reaches after the first frame is transmitted; a case where response frames are received from a predetermined number of wireless communication devices of the wireless communication devices specified in the fourth frame after the first frame is transmitted; and a case where response frames are received from all of the first wireless communication devices specified in the first frame. ### Claim 8 (depends on 1) The wireless communication device according to claim 1, wherein the receiver is configured to receive a sixth frame from one of the other wireless communication devices, the controlling circuitry is configured to select, when the sixth frame is received from the first wireless communication devices from among wireless communication devices other than one of the other wireless communication devices; and select, the second wireless communication devices from among the one of the other wireless communication devices and the first wireless communication devices which have transmitted the response frames. ### Claim 9 (depends on 1) The wireless communication device according to claim 1, further comprising at least one antenna. ### Claim 10 A wireless communication device communicating with a plurality of other wireless communication devices, comprising: controlling circuitry configured to select, from among the other wireless communication devices, first wireless communication devices for inquiring whether to have data for uplink multiuser multiplexing transmission and determine parameter information of a contention window used in CSMA/CA (carrier sense multiple access/collision avoidance) for the first wireless communication devices on a basis of a number of the first wireless communication devices; a transmitter configured to transmit a first frame to the first wireless communication devices, wherein the first frame includes information to specify the first wireless communication devices and the parameter information, and the first frame instructs the first wireless communication devices to use the contention window based on the parameter information for acquisition of transmission right for transmission of a response frame for the first frame; and a receiver configured to sequentially receive second frames transmitted based on the acquired transmission right from the first wireless communication devices in a single user manner, wherein the second frames are response frames for the first frame and include identification of whether the first wireless communication devices have the data for uplink multiuser multiplexing transmission, wherein the controlling circuitry is configured to specify wireless communication devices having the data for uplink multiuser multiplexing transmission from among the first wireless communication devices based on the received second frames and to select second wireless communication devices for execution of the uplink multiuser multiplexing transmission from among the specified wireless communication devices. ### Claim 11 A wireless communication device comprising: a receiver configured to receive a first frame including information to specify one or more wireless communication devices from a base station; and controlling circuitry configured to determine parameter information of a contention window used in CSMA/CA based on a number of the wireless communication devices specified in the first frame and perform carrier sensing during a backoff time determined based on a value selected randomly from the contention window specified by the parameter information; and a transmitter configured to transmit a response frame for the first frame in a single user manner in accordance with a transmission right acquired when a result of the carrier sensing is idle. ### Claim 12 (depends on 11) The wireless communication device according to claim 11, wherein the parameter information defines a range of random numbers as the contention window. ### Claim 13 (depends on 11) The wireless communication device according to claim 11, wherein the transmitter is configured to transmit the response frame, for the first frame when the first frame includes information to specify the wireless communication device and when the wireless communication device has data for uplink multiuser multiplexing transmission. ### Claim 14 (depends on 13) The wireless communication device according to claim 13, wherein the response frame for the first frame includes information for specifying whether the wireless communication device has the data for uplink multiuser multiplexing transmission. ### Claim 15 (depends on 11) The wireless communication device according to claim 11, further comprising at least one antenna.