# US 2018/0324701 A1 · Efficient retransmissions for wakeup radios > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0324701 A1 - Document ID: US20180324701A1 - Status: Published application - Kind: A1 - Application number: 15/970,374 - Filed: 2018-05-03 - Published: 2018-11-08 - Earliest claimed: 2017-05-05 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Yanjun Sun; Alfred Asterjadhi; George Cherian; Abhishek Pramod Patil; Yan Zhou; Bin Tian - Web page: https://patentgrep.com/patent/US20180324701A1 ## CPC - H04W 52/0235: {where the received signal is a power saving command} - H04L 1/189: {Transmission or retransmission of more than one copy of a message} - H04W 4/06: Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services - H04W 52/0219: {where the power saving management affects multiple terminals} - H04W 52/0229: {where the received signal is a wanted signal} - H04W 52/028: {switching on or off only a part of the equipment circuit blocks} - 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 Methods, systems, and devices for wireless communication are described. An access point (AP) may broadcast or multicast a wakeup transmission to wakeup radios (WURs) of a group of wireless and determine to retransmit the first wakeup transmission (e.g., for redundancy). The AP may transmit a second wakeup transmission to the WURs, the second wakeup transmission including an indication that the second wakeup transmission is a retransmission of the first wakeup transmission. The wireless devices may receive the indication that the second wakeup transmission is a retransmission, and may power up a main radio to receive a beacon based on whether or not the previous or originally wakeup transmission was received (e.g., determined via the indication included in the received wakeup message). In some cases, the AP may identify that some wireless devices failed to receive the first wakeup transmission, and may transmit a second wakeup transmission to those identified stations. ## Claims ### Claim 1 An apparatus for wireless communication, comprising: a memory that stores instructions; and a processor coupled with the memory, wherein the processor and the memory are configured to: receive, at a wakeup radio of a station, a first wakeup transmission addressed to a group of stations that includes the station, wherein the first wakeup transmission indicates to the station to power on a second radio of the station to communicate with an access point; and identify that the first wakeup transmission is a retransmission of a prior wakeup transmission for the group of stations based at least in part on an indication included in the first wakeup transmission. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the processor and memory are configured to: determine that the station failed to receive the prior wakeup transmission; and power on the second radio of the station to communicate with the access point based at least in part on receiving the first wakeup transmission. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the processor and memory are configured to: receive, at the wakeup radio of the station, the prior wakeup transmission; and refrain from powering on the second radio of the station to communicate with the access point in response to the first wakeup transmission based at least in part on the identifying that the indication that the first wakeup transmission is the retransmission of the prior wakeup transmission. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the indication that the first wakeup transmission is the retransmission of the prior wakeup transmission comprises a first sequence number. ### Claim 5 (depends on 4) The apparatus of claim 4, wherein the processor and memory are configured to identify that the first wakeup transmission is the retransmission of the prior wakeup transmission for the group of stations by being configured to: compare the first sequence number included in the first wakeup transmission to a second sequence number in the prior wakeup transmission. ### Claim 6 (depends on 4) The apparatus of claim 4, wherein the first sequence number is included in a type dependent control field of the first wakeup transmission. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein: the first wakeup transmission is scrambled based at least in part on a scrambling sequence; the processor and memory are configured to identify that the first wakeup transmission is the retransmission of the prior wakeup transmission for the group of stations by being configured to identify a successful descrambling sequence of one or more candidate descrambling sequences; and the processor and memory are configured to determine that the first wakeup transmission is the retransmission of the prior wakeup transmission based at least in part on the identified successful descrambling sequence. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the first wakeup transmission comprises a unicast transmission addressed to the station. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein the processor and memory are configured to: receive an indication of a time window for the first wakeup transmission. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the time window is for wakeup transmissions that are broadcast, or multicast, or a combination thereof. ### Claim 11 (depends on 9) The apparatus of claim 9, wherein the time window comprises a periodicity, an offset from a reference point in time, a length of the time window, or a combination thereof. ### Claim 12 (depends on 1) The apparatus of claim 1, wherein the first wakeup transmission is received in a first time window and the prior wakeup transmission is received in a prior transmission window. ### Claim 13 (depends on 1) The apparatus of claim 1, wherein the apparatus is a wireless communication terminal and further comprises an antenna and a transceiver. ### Claim 14 An apparatus for wireless communication, comprising: a memory that stores instructions; and a processor coupled with the memory, wherein the processor and the memory are configured to: transmit a first wakeup transmission to wakeup radios of a group of stations; determine to retransmit the first wakeup transmission to the group of stations; and transmit a second wakeup transmission to the wakeup radios of the group of stations, the second wakeup transmission including an indication that the second wakeup transmission is a retransmission of the first wakeup transmission. ### Claim 15 (depends on 14) The apparatus of claim 14, wherein the indication that the second wakeup transmission is the retransmission of the first wakeup transmission comprises a sequence number. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein the sequence number is included in a type dependent control field of the first wakeup transmission. ### Claim 17 (depends on 14) The apparatus of claim 14, wherein the processor and memory are configured to: scramble, based at least in part on a first scrambling sequence, at least a portion of the first wakeup transmission prior to transmitting the first wakeup transmission; and scramble, based at least in part on the first scrambling sequence, at least a portion of the second wakeup transmission prior to transmitting the second wakeup transmission to provide the indication that the second wakeup transmission is the retransmission of the first wakeup transmission. ### Claim 18 (depends on 14) The apparatus of claim 14, wherein the second wakeup transmission comprises a unicast transmission addressed to a station of the group of stations. ### Claim 19 (depends on 14) The apparatus of claim 14, wherein the processor and memory are configured to: transmit an indication of a time window for the first wakeup transmission. ### Claim 20 (depends on 19) The apparatus of claim 19, wherein the time window is for wakeup transmissions that are broadcast, or multicast, or a combination thereof. ### Claim 21 (depends on 19) The apparatus of claim 19, wherein the time window comprises a periodicity, an offset from a reference point in time, a length of the time window, or a combination thereof ### Claim 22 An apparatus for wireless communication, comprising: a memory that stores instructions; and a processor coupled with the memory, wherein the processor and the memory are configured to: transmit a first wakeup transmission to wakeup radios of a group of stations, the first wakeup transmission addressed to the group of stations, and the first wakeup transmission indicating to each station of the group of stations to power on a second radio to communicate with the apparatus; identify that one or more stations of the group of stations failed to receive the first wakeup transmission; and transmit a second wakeup transmission to the identified one or more stations, the second wakeup transmission addressed individually to the one or more stations. ### Claim 23 (depends on 22) The apparatus of claim 22, wherein the second wakeup transmission is a retransmission of the first wakeup transmission. ### Claim 24 (depends on 22) The apparatus of claim 22, wherein the second wakeup transmission addressed individually to the one or more stations comprises a unicast transmission or a multicast transmission. ### Claim 25 (depends on 22) The apparatus of claim 22, wherein the processor and memory are configured to: transmit an indication of a time window for the first wakeup transmission. ### Claim 26 A method for wireless communication at a station, comprising: receiving, at a wakeup radio of the station, a first wakeup transmission addressed to a group of stations that includes the station, wherein the first wakeup transmission indicates to the station to power on a second radio of the station to communicate with an access point; and identifying that the first wakeup transmission is a retransmission of a prior wakeup transmission for the group of stations based at least in part on an indication included in the first wakeup transmission. ### Claim 27 (depends on 26) The method of claim 26, further comprising: determining that the station failed to receive the prior wakeup transmission; and powering on the second radio of the station to communicate with the access point based at least in part on receiving the first wakeup transmission. ### Claim 28 (depends on 26) The method of claim 26, further comprising: receiving, at the wakeup radio of the station, the prior wakeup transmission; and refraining from powering on the second radio of the station to communicate with the access point in response to the first wakeup transmission based at least in part on the identifying that the indication that the first wakeup transmission is the retransmission of the prior wakeup transmission. ### Claim 29 (depends on 26) The method of claim 26, wherein the indication that the first wakeup transmission is the retransmission of the prior wakeup transmission comprises a sequence number. ### Claim 30 (depends on 26) The method of claim 26, further comprising: receiving an indication of a time window for the first wakeup transmission, the time window for wakeup transmissions that are broadcast, or multicast, or a combination thereof.