# US 2020/0288476 A1 · Data transmission method and device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0288476 A1 - Document ID: US20200288476A1 - Status: Published application - Kind: A1 - Application number: 16/825,749 - Filed: 2020-03-20 - Published: 2020-09-10 - Earliest claimed: 2013-09-29 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Xun YANG; Tianyu WU; Yunbo LI - Web page: https://patentgrep.com/patent/US20200288476A1 ## CPC - H04W 72/0453: Resources in frequency domain, e.g. a carrier in FDMA - H04L 1/1854: {Scheduling and prioritising arrangements} - H04L 1/1874: {Buffer management} - H04L 1/1896: {ARQ related signaling} - H04L 5/0055: {Physical resource allocation for ACK/NACK (for physical mapping arrangements in ARQ protocols H04L1/1861)} - H04W 74/0816: with collision avoidance - 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 Disclosed is a data transmission method. The method comprises: reserving a first channel and a second channel, where the first channel is used for transmitting data and the second channel is used for transmitting ACKs; sending data to a receiving end on the first channel that is reserved; receiving an ACK that is sent by the receiving end and corresponds to the data on the second channel that is reserved and determining whether the data needs to be cached based on information carried in the ACK; and if the information carried in the ACK indicates that the receiving end has correctly received the data, clearing the data that is cached by a sending end. Through separate transmission of the data and the ACK, an efficiency problem of the sending end in providing MAC in a wireless system in a condition of a limited cache capacity is resolved. ## Claims ### Claim 1 A method for transmitting data, the method comprising: reserving, by a first device, a first channel and a second channel by sending a channel reservation frame to a second device, wherein the channel reservation frame indicates a first duration and a second duration and the first channel is for communicating the data during the first duration and the second channel is for communicating an acknowledgement (ACK) associated with the data during the second duration; and in response to successfully reserving the first channel and the second channel: sending, on the reserved first channel, the data to the second device during the first duration; and receiving, on the reserved second channel, the ACK associated with the data from the second device during the second duration. ### Claim 2 (depends on 1) The method according to claim 1, wherein sending the channel reservation frame to the second device comprises: sending, by the first device, on the first channel, a first channel reservation frame to the second device; sending, by the first device, on the second channel, a second channel reservation frame to the second device, wherein the first channel reservation frame is used to reserve the first channel and carry information regarding the first duration for reserving the first channel, and wherein the second channel reservation frame is used to reserve the second channel and carry information regarding the second duration for reserving the second channel; and the method further comprises: determining, by the first device, whether the first channel is successfully reserved, based on at least one of a response frame of the first channel reservation frame and a response frame of the second channel reservation frame from the second device; and determining, by the first device, whether the second channel is successfully reserved, based on at least one of the response frame of the first channel reservation frame and the response frame of the second channel reservation frame from the second device. ### Claim 3 (depends on 2) The method according to claim 2, wherein a maximum cache capacity is carried in a preamble or a capability field of at least one of the first channel reservation frame and the second channel reservation frame, wherein the maximum cache capacity is used by the second device to determine a latest time for sending the ACK. ### Claim 4 (depends on 3) The method according g to the data to the first device to claim 3, wherein the method further comprises: determining, by the second device, a time for reaching the maximum cache capacity of the first device based on a rate at which the first device sends the data, the rate being carried by the preamble; or receiving, by the second device, information regarding the time for reaching the maximum cache capacity of the first device from the first device; and the method further comprises: sending, by the second device, the ACK to the first device in a limited contention-free manner or via carrier sense multiple access (CSMA); or before the time for reaching the maximum cache capacity of the first device: sending, by the second device, the ACK to the first device in response to an idle PCF inter-frame space (PIFS) time of the second channel elapsing, a short inter-frame space (SIFS) time of the preamble elapsing, or a response request frame associated with to the data being sent by the first device. ### Claim 5 (depends on 3) The method according to claim 3, wherein sending, on the reserved first channel, the data to the second device comprises: sending, by the first device, on the reserved first channel, the data to a plurality of second devices via downlink multi-user transmission; the method further comprises: sending, by the first device, on the reserved second channel, response request frames associated with the data to the plurality of second devices; wherein: in response to the plurality of second devices supporting uplink multi-user transmission and receiving the response request frames, the plurality of second devices send acknowledgements (ACKs) to the first device at a same time via uplink multi-user transmission before a minimum time for reaching maximum cache capacities of the first device; or in response to the plurality of second devices not all supporting the uplink multi-user transmission and receiving the response request frames, the plurality of second devices determine the times for reaching the maximum cache capacities of the first device, based on rates carried by the preamble at which the first device sends, respectively, the data to the plurality of second devices, and the plurality of second devices send, respectively, the ACKs to the first device before the times for reaching the maximum cache capacities of the first device; or the plurality of second devices send on the second channel the ACKs to the first device in a limited contention-free manner, wherein receiving, on the reserved second channel, the ACK associated with the data comprises: receiving, by the first device, on the second channel, the ACKs associated with the data from the plurality of second devices. ### Claim 6 (depends on 3) The method according to claim 3, wherein sending, on the reserved first channel, the data to the second device comprises: sending, by a plurality of first devices, on the first channel, the data to the second device via uplink multi-user transmission, and the method further comprises: determining, by the second device, latest times for reaching maximum cache capacities of the plurality of first devices based on rates carried by preambles at which the plurality of first devices send the data to the second device, so that before a minimum time for reaching the maximum cache capacities of the plurality of first devices, the second device sends acknowledgements (ACKs) to the plurality of first devices at a same time via downlink multi-user transmission; or sending, by the plurality of first devices, information regarding latest times to the second device, so that before the minimum time for reaching the maximum cache capacities of the plurality of first devices, the second device sends the ACKs to the plurality of first devices at a same time via downlink multi-user transmission; or determining, by the second device, the times for reaching the maximum cache capacities of the plurality of first devices based on the rates carried by the preambles at which the plurality of first devices send the data to the second device, so that before the times for reaching the maximum cache capacities of the plurality of first devices, the second device sends the ACKs to the plurality of first devices; or sending, by the second device, on the second channel, the ACKs to the plurality of first devices in a limited contention-free manner or via carrier sense multiple access (CSMA), wherein receiving, on the reserved second channel, the ACK associated with the data from the second device comprises: receiving, by the plurality of first devices, on the second channel, the ACKs associated with the data from the second device. ### Claim 7 (depends on 3) The method according to claim 3, wherein sending, on the reserved first channel, the data to the second device comprises: sending, by a plurality of first devices, on the first channel, the data to a plurality of second devices, via cooperative transmission; and the method further comprises: sending, by the plurality of first devices, on the reserved second channel, response request frames associated with the data, via a poll, so that the plurality of second devices receive the response request frames and after a short inter-frame space (SIFS), sends ACKs to the plurality of first devices; or requesting, by the plurality of first devices, the plurality of second devices to send the ACKs, on the second channel in a limited contention-free manner; or sending, by the plurality of second devices, the ACKs to the plurality of first devices in a limited contention-free manner, wherein receiving, on the reserved second channel, the ACK associated with the data from the second device comprises: receiving, by the plurality of first devices, on the second channel, the ACKs associated with the data from the plurality of second devices. ### Claim 8 (depends on 4) The method according to claim 4, wherein a starting time for channel reservation is carried in at least one of the first channel reservation frame and the second channel reservation frame, in the data or in the preamble. ### Claim 9 (depends on 1) The method according to claim 1, further comprising: sending, by the first device, an instruction for returning to a preset operating mode to the second device in response to successfully reserving, by the first device, at least one of the first channel and the second channel. ### Claim 10 A method for transmitting data, the method comprising: reserving, by a second device, a first channel and a second channel in response to receiving a channel reservation frame from a first device, wherein the channel reservation frame indicates a first duration and a second duration and the first channel is for communicating the data during the first duration and the second channel is for communicating an acknowledgement (ACK) associated with the data during the second duration; and in response to successfully reserving the first channel and the second channel: receiving, by the second device, the data from the first device on the reserved first channel during the first duration; and receiving, by the second device, during the second duration and on the reserved second channel, the ACK associated with the data sent by the first device. ### Claim 11 (depends on 10) The method according to claim 10, wherein receiving the channel reservation frame from the first device comprises: receiving, by the second device, on the first channel, a first channel reservation frame from the first device, and receiving, by the second device, on the second channel, a second channel reservation frame from the first device, wherein the first channel reservation frame is used to reserve the first channel and carry information regarding the first duration for reserving the first channel, and the second channel reservation frame is used to reserve the second channel and carry information regarding the second duration for reserving the second channel, and reserving the first channel and the second channel comprises: sending, by the second device, at least one of a response frame of the first channel reservation frame and a response frame of the second channel reservation frame to the first device for enabling the first device to determine whether the first channel is successfully reserved based on the at least one of the response frames of the first and second channel reservation frames from the second device, and for enabling the first device to determine whether the second channel is successfully reserved based on the at least one of the response frames of the first and second channel reservation frames from the second device. ### Claim 12 (depends on 11) The method according to claim 11, wherein a maximum cache capacity is carried in at least one of the first channel reservation frame and the second channel reservation frame, in a preamble or in a capability field, wherein the maximum cache capacity is used by the second device to determine a latest time for sending the ACK associated with the data to the first device. ### Claim 13 (depends on 12) The method according to claim 12, wherein the method further comprises: determining, by the second device, a time for reaching the maximum cache capacity of the first device, based on a rate at which the first device sends the data, the rate being carried by the preamble; or receiving, by the second device, information regarding the time for reaching the maximum cache capacity of the first device from the first device; and the method further comprises: sending, by the second device, the ACK to the first device in a limited contention-free manner or via carrier sense multiple access (CSMA); or before the time for reaching the maximum cache capacity of the first device: sending, by the second device, the ACK to the first device in response to an idle PCF inter-frame space (PIFS) time of the second channel elapsing, a short inter-frame space (SIFS) time of the preamble elapsing, or a response request frame associated with the data being sent by the first device. ### Claim 14 (depends on 12) The method according to claim 12, wherein receiving the data from the first device on the first channel comprises: sending, by the first device, on the reserved first channel, the data to a plurality of second devices via downlink multi-user transmission; wherein the method further comprises: sending, by the first device, on the reserved second channel, response request frames associated with the data to the plurality of second devices; and wherein, in response to the plurality of second devices supporting uplink multi-user transmission and receiving the response request frames, the plurality of second devices send acknowledgements (ACKs) to the first device at a same time via uplink multi-user transmission before a minimum time for reaching maximum cache capacities of the first device; or in response to the plurality of second devices not all supporting the uplink multi-user transmission and receiving the response request frames, the plurality of second devices determine the times for reaching the maximum cache capacities of the first device, based on rates at which the first device sends respectively the data to the plurality of second devices carried by the preamble, and the plurality of second devices send respectively the ACKs to the first device before the times for reaching the maximum cache capacities of the first device; or the plurality of second devices send on the second channel, the ACKs to the first device in a limited contention-free manner, wherein the method further comprises receiving, by the first device, on the second channel, the ACKs associated with the data from the plurality of second devices. ### Claim 15 (depends on 12) The method according to claim 12, wherein receiving the data from the first device on the first channel comprises: sending, by a plurality of first devices, on the first channel, the data to the second device via uplink multi-user transmission; and the method further comprises: determining, by the second device, latest times for reaching maximum cache capacities of the plurality of first devices based on rates carried by preambles at which the plurality of first devices send the data to the second device, so that before a minimum time for reaching the maximum cache capacities of the plurality of first devices, the second device sends acknowledgements (ACKs) to the plurality of first devices at a same time via downlink multi-user transmission; or sending, by the plurality of first devices, information regarding latest times to the second device, so that before the minimum time for reaching the maximum cache capacities of the plurality of first devices, the second device sends the ACKs to the plurality of first devices at a same time via downlink multi-user transmission; or determining, by the second device, the times for reaching the maximum cache capacities of the plurality of first devices based on the rates at which the plurality of first devices send the data to the second device carried by the preambles, so that before the times for reaching the maximum cache capacities of the plurality of first devices, the second device sends the ACKs to the plurality of first devices; wherein sending, on the reserved second channel, the ACK associated with the data to the first device comprises: sending, by the second device, on the second channel, the ACKs to the plurality of first devices in a limited contention-free manner or via carrier sense multiple access (CSMA); and receiving, by the plurality of first devices, on the second channel, the ACKs associated with the data sent by the second device. ### Claim 16 (depends on 12) The method according to claim 12, wherein the method further comprises: sending, by a plurality of first devices, on the first channel, the data to a plurality of second devices via cooperative transmission; and the method further comprises: sending, by the plurality of first devices, on the reserved second channel, response request frames associated with the data, via a poll, so that the plurality of second devices receive the response request frames and after a short inter-frame space (SIFS), and send ACKs to the plurality of first devices; or requesting, by the plurality of first devices, the plurality of second devices to send the ACKs, on the second channel in a limited contention-free manner; or sending, by the plurality of second devices, the ACKs to the plurality of first devices in a limited contention-free manner; and the method further comprises receiving, by the plurality of first devices, on the second channel, the ACKs associated with the data from the plurality of second devices. ### Claim 17 (depends on 13) The method according to claim 13, wherein a starting time for channel reservation is carried in at least one of the first channel reservation frame and the second channel reservation frame and in the data or in the preamble. ### Claim 18 A first device comprising a processor and a non-transitory computer-readable medium having processor-executable instructions stored thereon, the processor-executable instructions, when executed by the processor, facilitating the following: reserving a first channel and a second channel by sending a channel reservation frame to a second device, wherein the channel reservation frame indicates a first duration and a second duration and the first channel is for data during the first duration and the second channel is for an acknowledgement (ACK) associated with the data during the second duration; in response to successfully reserving the first channel and the second channel: sending, on the reserved first channel, the data to the second device during the first duration; and receiving, on the reserved second channel, the ACK associated with the data from the second device during the second duration. ### Claim 19 (depends on 18) The first device according to claim 18, wherein the processor-executable instructions, when executed, further facilitate: sending on the first channel a first channel reservation frame to the second device, and sending on the second channel a second channel reservation frame to the second device, wherein the first channel reservation frame is for reserving the first channel and carry information regarding the first duration for reserving the first channel, and the second channel reservation frame is for reserving the second channel and carry information regarding the second duration for reserving the second channel; determining whether the first channel is successfully reserved based on at least one of a response frame of the first channel reservation frame and a response frame of the second channel reservation frame from the second device; and determining whether the second channel is successfully reserved based on at least one of the response frame of the first channel reservation frame and the response frame of the second channel reservation frame from the second device. ### Claim 20 (depends on 19) The first device according to claim 19, wherein a maximum cache capacity is carried in at least one of the first channel reservation frame and the second channel reservation frame, in a preamble or in a capability field, wherein the maximum cache capacity is usable by the second device to determine a latest time for sending the ACK associated with the data to the first device.