# US 2021/0243792 A1 · Communication apparatus, control method therefor and computer-readable storage medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0243792 A1 - Document ID: US20210243792A1 - Status: Published application - Kind: A1 - Application number: 17/233,990 - Filed: 2021-04-19 - Published: 2021-08-05 - Earliest claimed: 2018-10-19 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Masatomo Ouchi - Web page: https://patentgrep.com/patent/US20210243792A1 ## CPC - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04W 74/006: {in the downlink, i.e. towards the terminal} - H04W 72/121: for groups of terminals or users - H04W 74/04: Scheduled access (hybrid access H04W74/02) - H04W 84/12: WLAN [Wireless Local Area Networks] - H04W 74/004: {in the uplink, i.e. towards network} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A communication apparatus for transmitting, to a plurality of terminals, a trigger frame for executing uplink transmission: obtains, from each of the plurality of terminals, ability information indicating a preparation time necessary to start transmission after a resource unit; selects terminals as destinations of one trigger frame from the plurality of terminals; and transmits the trigger frame for the selected terminals by adding a padding area to ensure the preparation times of the selected terminals. The communication apparatus selects the terminals from the plurality of terminals based on the pieces of ability information so that a total sum of the added padding area becomes small. ## Claims ### Claim 1 A communication apparatus for transmitting, to a plurality of terminals, a trigger frame for executing uplink transmission, the apparatus comprising: an obtaining unit configured to obtain, from each of the plurality of terminals, ability information indicating a preparation time necessary to start transmission after a resource unit to be used is designated by the trigger frame; a selecting unit configured to select terminals as destinations of one trigger frame from the plurality of terminals; and a transmitting unit configured to transmit the trigger frame for the selected terminals by adding a padding area to ensure the preparation times of the terminals selected by the selecting unit, wherein the selecting unit selects the terminals from the plurality of terminals based on the pieces of ability information so that a total sum of the padding area added by the transmitting unit becomes small. ### Claim 2 (depends on 1) The communication apparatus according to claim 1, wherein the selecting unit decides a selection order of the plurality of terminals so that terminals of the same preparation time are continuous, and selects the terminals as the destinations of the one trigger frame in the selection order. ### Claim 3 (depends on 1) The communication apparatus according to claim 1, wherein the selecting unit selects the terminals so terminals of different preparation times are not mixed in the one trigger frame as long as the number of trigger frames to be transmitted does not increase. ### Claim 4 (depends on 1) The communication apparatus according to claim 1, wherein the number of trigger frames to be transmitted is a smallest integer value not less than a real value obtained by dividing the number of the plurality of terminals by a maximum number of destinations that can be included in the one trigger frame. ### Claim 5 (depends on 1) The communication apparatus according to claim 1, wherein the transmitting unit adds a padding area corresponding to a maximum preparation time among the preparation times requested by the terminals selected by the selecting unit. ### Claim 6 (depends on 1) The communication apparatus according to claim 1, wherein the plurality of terminals are formed by terminals to which a trigger frame of a type other than a type in which destination terminals are decided based on downlink communication is transmitted. ### Claim 7 (depends on 6) The communication apparatus according to claim 6, wherein the trigger frame of the type other than the type in which the destination terminals are decided based on the downlink communication is a trigger frame of a type other than MU-BAR, MU-RTS, and GCR MU-BAR. ### Claim 8 (depends on 1) The communication apparatus according to claim 1, wherein the plurality of terminals are formed by terminals as transmission targets of a trigger frame, whose effective data of responses have the same length. ### Claim 9 (depends on 8) The communication apparatus according to claim 8, wherein the plurality of terminals are formed by terminals whose trigger frame types are Basic Trigger and whose transmission buffer amounts are equal to each other. ### Claim 10 (depends on 1) The communication apparatus according to claim 1, further comprising an assigning unit configured to assign AIDs so that the terminals of the same preparation time are continuous when the type of the trigger frame is NFRP. ### Claim 11 (depends on 1) The communication apparatus according to claim 1, wherein the transmitting unit decreases the time ensured by the padding area by arranging a field corresponding to a terminal whose preparation time is short after a field corresponding to a terminal whose preparation time is long in the one trigger frame. ### Claim 12 (depends on 1) The communication apparatus according to claim 1, wherein the selecting unit preferentially selects terminals of the same transmission quality as the destination terminals of the one trigger frame. ### Claim 13 (depends on 1) The communication apparatus according to claim 1, wherein the communication apparatus is an access point complying with IEEE802.11ax, and the ability information indicating the preparation time is MinTrigProcTime defined in IEEE802.11ax. ### Claim 14 (depends on 13) The communication apparatus according to claim 13, wherein the obtaining unit obtains MinTrigProcTime from a Trigger Frame Mac Padding Duration of an HE Capabilities element in a Management frame. ### Claim 15 A control method for a communication apparatus for transmitting, to a plurality of terminals, a trigger frame for executing uplink transmission, the method comprising: obtaining, from each of the plurality of terminals, ability information indicating a preparation time necessary to start transmission after a resource unit to be used is designated by the trigger frame; selecting terminals as destinations of one trigger frame from the plurality of terminals; and transmitting the trigger frame for the selected terminals by adding a padding area to ensure the preparation times of the terminals selected in the selecting, wherein in the selecting, the terminals are selected from the plurality of terminals based on the pieces of ability information so that a total sum of the padding area added in the transmitting becomes small. ### Claim 16 A non-transitory computer-readable storage medium storing a program for causing a computer to execute a control method for a communication apparatus for transmitting, to a plurality of terminals, a trigger frame for executing uplink transmission, the method comprising: obtaining, from each of the plurality of terminals, ability information indicating a preparation time necessary to start transmission after a resource unit to be used is designated by the trigger frame; selecting terminals as destinations of one trigger frame from the plurality of terminals; and transmitting the trigger frame for the selected terminals by adding a padding area to ensure the preparation times of the terminals selected in the selecting, wherein in the selecting, the terminals are selected from the plurality of terminals based on the pieces of ability information so that a total sum of the padding area added in the transmitting becomes small.