# US 2013/0155955 A1 · Wireless communication apparatus and wireless communication method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0155955 A1 - Document ID: US20130155955A1 - Status: Published application - Kind: A1 - Application number: 13/717,361 - Filed: 2012-12-17 - Published: 2013-06-20 - Earliest claimed: 2011-12-20 - Assignees: Kabushki Kaisha Toshiba - Inventors: Toshihisa NABETANI; Ryoko MATSUO; Tomoko ADACHI; Tomoya TANDAI - Web page: https://patentgrep.com/patent/US20130155955A1 ## CPC - H04W 74/0816: with collision avoidance - H04W 28/18: Negotiating wireless communication parameters - H04L 1/1887: {Scheduling and prioritising arrangements} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract There is provided a wireless communication apparatus performing access control which starts transmission after a backoff time passes since an available state of a channel is detected through carrier sense, the backoff time being set based on a random value selected within a contention window width, including: a remaining time calculating unit calculating a remaining time untill a request delay time time-outs after data is generated and a setting unit setting the contention window width according to the remaining time calculated by the remaining time calculating unit. ## Claims ### Claim 1 A wireless communication apparatus performing access control which starts transmission after a backoff time passes since an available state of a channel is detected through carrier sense, the backoff time being set based on a random value selected within a contention window width, comprising: a remaining time calculating unit configured to calculate a remaining time untill a request delay time time-outs after data is generated; and a setting unit configured to set the contention window width according to the remaining time calculated by the remaining time calculating unit. ### Claim 2 (depends on 1) The apparatus according to claim 1, wherein if the remaining time is a first remaining time, the setting unit sets a first contention window width as the contention window width, and if the remaining time is a second remaining time, the setting unit sets a second contention window width as the contention window width, the second remaining time being longer than the first remaining time and the first contention window width being smaller than the second contention window width. ### Claim 3 (depends on 1) The apparatus according to claim 1, wherein the random value is generated using a probability density function of the random value, wherein an expectation value of the probability density function is set according to the remaining time calculated by the remaining time calculating unit, and wherein if the remaining time is a first remaining time, a first expectation value of the probability density function is set and if the remaining time is a second remaining time, a second expectation value of the probability density function is set, the first expectation value being smaller than the second expectation value. ### Claim 4 (depends on 1) The apparatus according to claim 1, wherein the remaining time calculating unit calculates the remaining time when Busy is detected during the backoff time. ### Claim 5 (depends on 1) The apparatus according to claim 1, wherein the remaining time calculating unit calculates the remaining time immediately after the available state of the channel is detected through the carrier sense. ### Claim 6 (depends on 1) The apparatus according to claim 1, wherein the remaining time calculating unit calculates the remaining time whenever retransmission of the data is determined. ### Claim 7 A wireless communication apparatus performing access control which starts transmission after a fixed time and a backoff time pass since an available state of a channel is detected through carrier sense, the backoff time being set based on a random value selected within a contention window width, comprising: a remaining time calculating unit configured to calculate a remaining time until a request delay time time-outs after data is generated; and a setting unit configured to set at least one of the fixed time and the contention window width according to the remaining time calculated by the remaining time calculating unit. ### Claim 8 (depends on 7) The apparatus according to claim 7, wherein if the remaining time is a first remaining time, the setting unit sets a first contention window and a first fixed time as the contention window width and the fixed time and if the remaining time is a second remaining time, the setting units sets a second contention window and a second fixed time as the contention window width and the fixed time, at least one of the first fixed time and the first contention window width being smaller than the second fixed time and the second contention window width. ### Claim 9 (depends on 8) The apparatus according to claim 8, wherein a sum of the first fixed time and a maximum backoff time settable from the first contention window width is smaller than the second fixed time. ### Claim 10 (depends on 7) The apparatus according to claim 7, wherein the remaining time calculating unit calculates the remaining time when Busy is detected during the fixed time. ### Claim 11 A wireless communication method performing access control which starts transmission after a backoff time passes since an available state of a channel is detected through carrier sense, the backoff time being set based on a random value selected within a contention window width, comprising: calculating a remaining time untill a request delay time time-outs after data is generated; and setting the contention window width according to the remaining time. ### Claim 12 (depends on 11) The method according to claim 11, wherein if the remaining time is a first remaining time, a first contention window width is set as the contention window width, and if the remaining time is a second remaining time, a second contention window width is set as the contention window width, the second remaining time being longer than the first remaining time and the first contention window width being smaller than the second contention window width. ### Claim 13 (depends on 11) The method according to claim 11, wherein the random value is generated using a probability density function of the random value, wherein an expectation value of the probability density function is set according to the remaining time, and wherein if the remaining time is a first remaining time, a first expectation value of the probability density function is set and if the remaining time is a second remaining time, a second expectation value of the probability density function is set, the first expectation value being smaller than the second expectation value. ### Claim 14 (depends on 11) The method according to claim 11, further comprising calculating the remaining time when Busy is detected during the backoff time. ### Claim 15 (depends on 11) The method according to claim 11, wherein further comprising calculating the remaining time immediately after the available state of the channel is detected through the carrier sense. ### Claim 16 (depends on 11) The method according to claim 11, wherein further comprising calculating the remaining time whenever retransmission of the data is determined. ### Claim 17 A wireless communication method performing access control which starts transmission after a fixed time and a backoff time pass since an available state of a channel is detected through carrier sense, the backoff time being set based on a random value selected within a contention window width, comprising: calculating a remaining time until a request delay time time-outs after data is generated; and setting at least one of the fixed time and the contention window width according to the remaining time. ### Claim 18 (depends on 17) The method according to claim 17, wherein if the remaining time is a first remaining time, a first contention window and a first fixed time are set as the contention window width and the fixed time and if the remaining time is a second remaining time, a second contention window and a second fixed time are set as the contention window width and the fixed time, at least one of the first fixed time and the first contention window width being smaller than the second fixed time and the second contention window width. ### Claim 19 (depends on 18) The method according to claim 18, wherein a sum of the first fixed time and a maximum backoff time settable from the first contention window width is smaller than the second fixed time. ### Claim 20 (depends on 17) The method according to claim 17, further comprising calculating the remaining time when Busy is detected during the fixed time.