# US 10,321,480 B2 · Channel access method in wireless LAN system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,321,480 B2 - Document ID: US10321480B2 - Status: Granted - Kind: B2 - Application number: 15/407,843 - Filed: 2017-01-17 - Published: 2017-05-04 - Granted: 2019-06-11 - Earliest claimed: 2012-08-16 - Assignees: Kt Corporation - Applicants: KT Corporation - Inventors: Yang Seok Jeong; Joo Young Kim - Web page: https://patentgrep.com/patent/US10321480B2 ## CPC - H04W 74/06: using polling - H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals} - H04W 52/0209: {in terminal devices} - H04W 52/0235: {where the received signal is a power saving command} - H04W 56/004: {compensating for timing error of reception due to propagation delay} - H04W 74/04: Scheduled access (hybrid access H04W74/02) - H04L 1/16: in which the return channel carries supervisory signals, e.g. repetition request signals - H04L 5/0055: {Physical resource allocation for ACK/NACK (for physical mapping arrangements in ARQ protocols H04L1/1861)} - H04W 84/12: WLAN [Wireless Local Area Networks] - Y02D 30/70: in wireless communication networks - 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) - Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE ## Abstract A channel access method in a wireless LAN system is disclosed. The channel access method for a terminal comprises the steps of: receiving a beacon transmitted from an access point; determining a channel access slot of a terminal allocated on the basis of the beacon; transmitting a data transmission request from the channel access slot to the access point; and receiving data transmission slot allocation information corresponding to the data transmission request from the access point. Thus, the present invention can reduce power consumption of the terminal. ## Claims ### Claim 1 A method for a terminal in a wireless local area network, the method comprising: transmitting a first frame to an access point; and receiving, in response to the first frame, from the access point, a second frame including data transmission time information, wherein a PHY preamble of the second frame includes the data transmission time information, wherein the second frame is a Null Data Packet (NDP) type acknowledgement frame which includes the PHY preamble without a Data field, wherein the terminal is changed to power save mode when the second frame is received, wherein the terminal is changed to awake mode from the power save mode at a time indicated by the data transmission time information, and wherein the data transmission time information includes time information in which data is to be transmitted to the terminal within a data transmission interval. ### Claim 2 (depends on 1) The method according to claim 1, wherein the access point transmits data to the terminal at a time indicated by the data transmission time information. ### Claim 3 (depends on 1) The method according to claim 1, wherein the NDP frame includes the PHY preamble without the Data field, and the PHY preamble includes a Short Training Field (STF) field, a Long Training Field (LTF) field and a Signal (SIG) field. ### Claim 4 (depends on 3) The method according to claim 3, wherein the SIG field includes the data transmission time information. ### Claim 5 (depends on 1) The method according to claim 1, wherein the first frame is a Power Save (PS)-Poll frame or a trigger frame. ### Claim 6 (depends on 1) The method of claim 1, wherein the data transmission time information includes a value for Time Synchronization Function (TSF). ### Claim 7 (depends on 1) The method of claim 1, wherein the data transmission time information includes an offset time information relative to a start time of data transmission period. ### Claim 8 A method for an access point in a wireless local area network, the method comprising: receiving a first frame from a terminal; and transmitting, in response to the first frame, to the terminal, a second frame including data transmission time information, wherein a PHY preamble of the second frame includes the data transmission time information, wherein the second frame is a Null Data Packet (NDP) type acknowledgement frame which includes the PHY preamble without a Data field, wherein the terminal is changed to power save mode when the second frame is received by the terminal, wherein the terminal is changed to awake mode from the power save mode at a time indicated by the data transmission time information, and wherein the data transmission time information includes time information in which data is to be transmitted to the terminal within a data transmission interval. ### Claim 9 A terminal in a wireless local area network, the terminal comprising: a transceiver; and a processor, wherein the processor is configured to: cause the transceiver to transmit a first frame to an access point; and cause the transceiver to receive, in response to the first frame, from the access point, a second frame including data transmission time information, wherein a PHY preamble of the second frame includes the data transmission time information, wherein the second frame is a Null Data Packet (NDP) type acknowledgement frame which includes the PHY preamble without a Data field, wherein the terminal is changed to power save mode when the second frame is received, wherein the terminal is changed to awake mode from the power save mode at a time indicated by the data transmission time information, and wherein the data transmission time information includes time information in which data is to be transmitted to the terminal within a data transmission interval. ### Claim 10 An access point in a wireless local area network, the access point comprising: a transceiver; and a processor, wherein the processor is configured to: cause the transceiver to receive a first frame from a terminal; and cause the transceiver to transmit, in response to the first frame, to the terminal, a second frame including data transmission time information, wherein a PHY preamble of the second frame includes the data transmission time information, wherein the second frame is a Null Data Packet (NDP) type acknowledgement frame which includes the PHY preamble without a Data field, wherein the terminal is changed to power save mode when the second frame is received by the terminal, wherein the terminal is changed to awake mode from the power save mode at a time indicated by the data transmission time information, and wherein the data transmission time information includes time information in which data is to be transmitted to the terminal within a data transmission interval.