# US 10,485,029 B2 · System and method for collision detection and mitigation with wake-up packets > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,485,029 B2 - Document ID: US10485029B2 - Status: Granted - Kind: B2 - Application number: 15/907,616 - Filed: 2018-02-28 - Published: 2018-09-13 - Granted: 2019-11-19 - Earliest claimed: 2017-03-07 - Assignees: Futurewei Technologies, Inc. - Applicants: Futurewei Technologies, Inc. - Inventors: Yunsong Yang - Web page: https://patentgrep.com/patent/US10485029B2 ## CPC - H04W 74/0825: {with collision detection} - H04L 1/00: Arrangements for detecting or preventing errors in the information received {(correcting synchronisation H04L7/00)} - H04W 52/0235: {where the received signal is a power saving command} - H04W 74/0816: with collision avoidance - 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 method for collision detection by a transmission device (TD) includes identifying one or more time periods of a signal generated by the TD. The one or more time periods correspond to periods during which the TD will not transmit energy on a shared channel. The method includes transmitting a subset of the signal. While a current time is within one of the one or more time periods, the transmitting the subset of the signal includes turning off a transmitter of the TD at a beginning of the time period, detecting energy received on the shared channel during a portion of the time period, turning on the transmitter of the TD before an end of the time period, and determining that the detected energy meets a collision threshold. Based on the detected energy meeting the collision threshold, the method includes determining that there is a transmission collision. ## Claims ### Claim 1 A method for collision detection by a transmission device (TD), the method comprising: identifying, by the TD, one or more time periods of a signal generated by the TD, the one or more time periods corresponding to periods during which the TD will not transmit energy on a shared channel; and transmitting, by the TD, a subset of the signal, wherein while a current time is within one of the one or more time periods, transmitting the subset of the signal comprises: turning off, by the TD, a transmitter of the TD at a beginning of the time period, detecting, by the TD, energy received on the shared channel during a portion of the time period, turning on, by the TD, the transmitter of the TD before an end of the time period, and determining, by the TD, that the detected energy meets a collision threshold, and based thereon, determining that there is a transmission collision. ### Claim 2 (depends on 1) The method of claim 1, wherein the signal is an On-off-keying (OOK) modulated signal. ### Claim 3 (depends on 1) The method of claim 1, wherein the signal is used for waking up a communications station from a sleep mode. ### Claim 4 (depends on 1) The method of claim 1, wherein the signal is a wake-up radio beacon. ### Claim 5 (depends on 1) The method of claim 1, wherein the TD is an access point (AP). ### Claim 6 (depends on 1) The method of claim 1, further comprising stopping, by the TD, the transmitting the signal when the detected energy meets the collision threshold. ### Claim 7 (depends on 1) The method of claim 1, further comprising retransmitting, by the TD, the signal at a later time in response to determining that the detected energy meets the collision threshold. ### Claim 8 (depends on 1) The method of claim 1, wherein each time period corresponds to an information bit “0” immediately followed by an information bit “1”. ### Claim 9 (depends on 1) The method of claim 1, wherein each time period corresponds to encoded bits “0 0”, and wherein each encoded bit “0” of the encoded bits “0 0” is modulated as an “off” symbol, for which the TD does not transmit energy on the shared channel. ### Claim 10 (depends on 1) The method of claim 1, further comprising obtaining, by the TD, an information related to a distance between the TD and a receiving device (RD), wherein the RD is an intended recipient of the signal. ### Claim 11 (depends on 10) The method of claim 10, wherein the information related to the distance is one of a physical distance between the TD and the RD or a signal path-loss between the TD and the RD. ### Claim 12 (depends on 10) The method of claim 10, wherein the collision threshold is determined in accordance with a function of the information related to the distance. ### Claim 13 (depends on 10) The method of claim 10, wherein determining that there is a transmission collision further comprises determining, by the TD, that the information related to the distance is less than a distance threshold. ### Claim 14 (depends on 1) The method of claim 1, further comprising: turning on, by the TD, a receiver of the TD to perform the detecting after turning off the transmitter; and turning off, by the TD, the receiver before turning the transmitter back on. ### Claim 15 (depends on 14) The method of claim 14, wherein each of the one or more time periods is of sufficient duration allowing sufficient time for the TD to perform all of the following within the time period: turning off the transmitter, turning on the receiver, detecting energy received on the shared channel during a subset of the time period using the receiver, turning off the receiver, and turning on the transmitter. ### Claim 16 (depends on 1) The method of claim 1, further comprising averaging, by the TD, the energy detected during each time period, wherein determining the transmission collision is in accordance with the averaged detected energy and the collision threshold. ### Claim 17 A transmitting device (TD) adapted to perform collision detection, the transmitting device comprising: one or more processors; and a computer readable storage medium storing programming for execution by the one or more processors, the programming including instructions to configure the transmitting device to: identify one or more time periods of a signal generated by the TD, the one or more time periods corresponding to periods during which the TD will not transmit energy on a shared channel, and transmit a subset of the signal, wherein while a current time is within one of the one or more time periods, transmitting the subset of the signal comprises: turn off a transmitter of the TD at a beginning of the time period, detect energy received on the shared channel during a portion of the time period, turn on the transmitter of the TD before an end of the time period, and determine that the detected energy meets a collision threshold, and based thereon, determine that there is a transmission collision. ### Claim 18 (depends on 17) The transmitting device of claim 17, wherein the one or more processors further execute the instructions to stop a transmission of the signal when the detected energy meets the collision threshold. ### Claim 19 (depends on 17) The transmitting device of claim 17, wherein the one or more processors further execute the instructions to retransmit the signal at a later time in response to determining that the detected energy meets the collision threshold. ### Claim 20 (depends on 17) The transmitting device of claim 17, wherein the one or more processors further execute the instructions to obtain an information related to a distance between the TD and a receiving device (RD), wherein the RD is an intended recipient of the signal. ### Claim 21 (depends on 20) The transmitting device of claim 20, wherein the one or more processors further execute the instructions to one of determine the collision threshold in accordance with a function of the information related to the distance or determine that the information related to the distance is less than a distance threshold. ### Claim 22 (depends on 17) The transmitting device of claim 17, wherein the one or more processors further execute the instructions to turn on a receiver of the TD to perform the detecting of the energy after turning off the transmitter, and turn off the receiver before turning the transmitter back on. ### Claim 23 (depends on 17) The transmitting device of claim 17, wherein the one or more processors further execute the instructions to average the energy detected during each time period, wherein the transmission collision is determined in accordance with the averaged detected energy and the collision threshold. ### Claim 24 A method for collision detection by a transmission device (TD), the method comprising: identifying, by the TD, a time period of an On-off-keying (OOK) modulated signal generated by the TD, the time period corresponding to a period during which the TD will not transmit energy on a shared channel; transmitting, by the TD, the OOK modulated signal over the shared channel prior to the time period; turning off, by the TD, a transmitter of the TD at a beginning of the time period; detecting, by the TD, energy received on the shared channel during a portion of the time period; and determining, by the TD, that the detected energy meets a collision threshold, and based thereon, determining that the OOK modulated signal experienced a transmission collision. ### Claim 25 (depends on 24) The method of claim 24, further comprising stopping, by the TD, the transmitting the OOK modulated signal when the detected energy meets the collision threshold. ### Claim 26 (depends on 24) The method of claim 24, further comprising retransmitting, by the TD, the OOK modulated signal at a later time in response to determining that the detected energy meets the collision threshold. ### Claim 27 (depends on 24) The method of claim 24, further comprising turning on, by the TD, a receiver of the TD to perform the detecting after turning off the transmitter.