# US 2020/0403687 A1 · Millimeter wave relay link discovery > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0403687 A1 - Document ID: US20200403687A1 - Status: Published application - Kind: A1 - Application number: 16/446,501 - Filed: 2019-06-19 - Published: 2020-12-24 - Earliest claimed: 2019-06-19 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Vasanthan RAGHAVAN; Tianyang BAI; Jung Ho RYU; Junyi LI - Web page: https://patentgrep.com/patent/US20200403687A1 ## CPC - H04B 7/0617: {for beam forming} - H04B 7/1555: {Selecting relay station antenna mode, e.g. selecting omnidirectional -, directional beams, selecting polarizations} - H04W 8/005: {Discovery of network devices, e.g. terminals} - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W 76/14: Direct-mode setup - H04W 48/12: using downlink control channel - H04W 48/16: Discovering, processing access restriction or access information - H04W 84/047: {using dedicated repeater stations} - H04W 88/04: adapted for relaying to or from another terminal or user - H04W 92/18: between terminal devices - H04B: TRANSMISSION - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Aspects of the disclosure relate to millimeter wave (mmWave) device discovery for relay communication using pseudo-omnidirectional beams. A first user equipment (UE) may transmit a synchronization signal over each pseudo-omnidirectional beam to enable a second UE to discover a presence of the second UE within a range of the first UE. Upon the occurrence of an external event, a base station may either trigger a beam training procedure with the second UE to establish a relay link between the first and second UEs or broadcast a message to all UEs requesting a relay link be established with the first UE. The first and second UEs may then select a directional beam pair link (BPL) for the relay link and establish the relay link to enable information to be relayed between the base station and the first UE via the relay link. ## Claims ### Claim 1 A method for wireless communication at a first user equipment (UE) in a wireless communication network, the method comprising: receiving a first signal from a second UE via at least one pseudo-omnidirectional beam to determine that the first UE is within a range of the second UE, wherein the first signal comprises at least one of a primary synchronization signal waveform or a secondary synchronization signal waveform within an uplink reference signal; receiving a second signal from a base station over a first link, the second signal indicating that the first UE establish a relay link with the second UE; and relaying information between the second UE and the base station via the first link and the relay link using a directional beam pair link with the second UE. ### Claim 2 (depends on 1) The method of claim 1, further comprising determining a cell identifier (ID) associated with the second UE based on the first signal. ### Claim 3 (depends on 2) The method of claim 2, further comprising: conveying the cell ID of the second UE to the base station to report a presence of the first UE within the range of the second UE; and storing the cell ID of the second UE. ### Claim 4 (depends on 1) The method of claim 1, wherein the second signal comprises a unicast message, the unicast message comprising a request for the first UE to initiate beam training with the second UE to select the directional beam pair link and to establish the relay link therebetween. ### Claim 5 (depends on 4) The method of claim 4, further comprising: receiving beam training information, wherein the beam training information comprises reference signal resources, a timing offset, and at least one beam pair link option to utilize for beam training. ### Claim 6 (depends on 5) The method of claim 5, wherein the at least one beam pair link option further comprises a list of beam pair link options, and further comprising: selecting the directional beam pair link for the relay link from the list of beam pair link options based on an order of the beam pair link options in the list. ### Claim 7 (depends on 5) The method of claim 5, wherein the reference signal resources for the beam training comprise a set of common resources. ### Claim 8 (depends on 5) The method of claim 5, wherein the reference signal resources for the beam training comprise a set of UE-specific resources. ### Claim 9 (depends on 4) The method of claim 4, further comprising: initiating a random access procedure with the second UE in response to either receiving the unicast message or receiving the first signal to establish a random access link with the second UE over the at least one pseudo-omnidirectional beam. ### Claim 10 (depends on 1) The method of claim 1, wherein the second signal comprises a broadcast message, and further comprising: initiating a random access procedure with the second UE in response to receiving the broadcast message to establish a random access link with the second UE over the at least one pseudo-omnidirectional beam. ### Claim 11 (depends on 10) The method of claim 10, further comprising: performing beam training with the second UE over the random access link to select the directional beam pair link. ### Claim 12 (depends on 1) The method of claim 1, further comprising: communicating with the second UE over the relay link utilizing a millimeter wave carrier frequency. ### Claim 13 (canceled) ### Claim 14 A first user equipment (UE), comprising: a wireless transceiver; a memory; and a processor communicatively coupled to the wireless transceiver and the memory, wherein the processor is configured to: receive a first signal from a second UE via at least one pseudo-omnidirectional beam to determine that the first UE is within a range of the second UE via the wireless transceiver, wherein the first signal comprises at least one of a primary synchronization signal waveform or a secondary synchronization signal waveform within an uplink reference signal; receive a second signal from a base station over a first link, the second signal indicating that the first UE establish a relay link with the second UE via the wireless transceiver; and relay information between the second UE and the base station via the first link and the relay link using a directional beam pair link with the second UE. ### Claim 15 (depends on 14) The first UE of claim 14, wherein the processor is further configured to: determine a cell identifier (ID) associated with the second UE based on the first signal. ### Claim 16 (depends on 15) The first UE of claim 15, wherein the processor is further configured to: convey the cell ID of the second UE to the base station to report the presence of the first UE within the range of the second UE; and store the cell ID of the second UE within the memory. ### Claim 17 (depends on 14) The first UE of claim 14, wherein the second signal comprises a unicast message, the unicast message comprising a request for the first UE to initiate beam training with the second UE to select the directional beam pair link and to establish the relay link therebetween, and wherein the processor is further configured to: receive beam training information, wherein the beam training information comprises reference signal resources, a timing offset, and at least one beam pair link option to utilize for beam training. ### Claim 18 (depends on 17) The first UE of claim 17, wherein the at least one beam pair link option further comprises a list of beam pair link options, and wherein the processor is further configured to: select the directional beam pair link for the relay link from the list of beam pair link options based on an order of the beam pair link options in the list. ### Claim 19 (depends on 14) The first UE of claim 14, wherein the second signal comprises a broadcast message, and the processor is further configured to: initiate a random access procedure with the second UE in response to receiving the broadcast message to establish a random access link with the second UE over the at least one pseudo-omnidirectional beam; perform beam training with the second UE over the random access link to select the directional beam pair link; and establish the relay link utilizing the directional beam pair link. ### Claim 20 A method of wireless communication at a first user equipment (UE) in a wireless communication network, the method comprising: broadcasting a signal via at least one pseudo-omnidirectional beam to enable a second UE to determine that the second UE is within a range of the first UE, wherein the signal comprises at least one of a primary synchronization signal waveform or a secondary synchronization signal waveform within an uplink reference signal; establishing a relay link with the second UE utilizing a directional beam pair link upon an occurrence of an external event; and communicating with a base station via the relay link. ### Claim 21 (depends on 20) The method of claim 20, further comprising: performing beam training with the second UE to select the directional beam pair link utilizing reference signal resources, a timing offset, and at least one beam pair link option provided by the base station to select the directional beam pair link for the relay link. ### Claim 22 (canceled) ### Claim 23 (depends on 20) The method of claim 20, wherein broadcasting the signal further comprises: broadcasting the signal pseudo-randomly over a set of common resources. ### Claim 24 (depends on 20) The method of claim 20, wherein broadcasting the signal further comprises: broadcasting the signal over a set of UE-specific resources. ### Claim 25 (depends on 20) The method of claim 20, wherein establishing the relay link with the second UE further comprises: receiving a random access message from the second UE to establish a random access link with the second UE over the at least one pseudo-omnidirectional beam; performing beam training with the second UE over the random access link to select the directional BPL; and establishing the relay link utilizing the directional beam pair link. ### Claim 26 (depends on 20) The method of claim 20, further comprising: communicating with the second UE over the relay link utilizing a millimeter wave carrier frequency. ### Claim 27 (depends on 20) The method of claim 20, wherein the external event comprises at least one of blockage of a first link between the first UE and the base station, fading of the first link, or initiation of assisted communication for the first link using the relay link. ### Claim 28 A first user equipment (UE), comprising: a wireless transceiver; a memory; and a processor communicatively coupled to the wireless transceiver and the memory, wherein the processor is configured to: broadcast a signal via at least one pseudo-omnidirectional beam and the wireless transceiver to enable a second UE to determine that the second UE is within a range of the first UE, wherein the signal comprises at least one of a primary synchronization signal waveform or a secondary synchronization signal waveform within an uplink reference signal; establish a relay link with the second UE utilizing a directional beam pair link upon an occurrence of an external event; and communicate with a base station via the relay link. ### Claim 29 (canceled) ### Claim 30 (depends on 28) The first UE of claim 28, wherein the processor is further configured to: receive a random access message from the second UE to establish a random access link with the second UE over the at least one pseudo-omnidirectional beam; perform beam training with the second UE over the random access link to select the directional BPL; and establish the relay link utilizing the directional beam pair link.