# US 11,115,944 B2 · Timing synchronization with neighbor nodes different from parent nodes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,115,944 B2 - Document ID: US11115944B2 - Status: Granted - Kind: B2 - Application number: 16/564,806 - Filed: 2019-09-09 - Published: 2020-04-09 - Granted: 2021-09-07 - Earliest claimed: 2018-10-08 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Muhammad Nazmul Islam; Navid Abedini; Samel Celebi; Tao Luo; Jianghong Luo; Karl Georg Hampel; Junyi Li - Web page: https://patentgrep.com/patent/US11115944B2 ## CPC - H04W 56/001: {Synchronization between nodes} - H04W 56/0015: {one node acting as a reference for the others} - H04L 1/0061: {Error detection codes} - H04L 1/0072: {Error control for data other than payload data, e.g. control data} - H04L 61/35: {involving non-standard use of addresses for implementing network functionalities, e.g. coding subscription information within the address or functional addressing, i.e. assigning an address to a function} - H04W 72/0446: Resources in time domain, e.g. slots or frames - H04W 72/21: in the uplink direction of a wireless link, i.e. towards the network - H04W 74/0833: Random access procedures, e.g. with 4-step access - 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 Methods, systems, and devices for wireless communications are described. A first node of an integrated access and backhaul (IAB) network may identify a second, neighboring non-parent node of the IAB network. The second node may be associated with a timing source which may provide more accurate timing information than the parent node of the first node. The first node may transmit a first random access message to the second node to initiate a random access procedure. The second node may transmit a second random access message to the first node, the second random access message including timing information based on the timing source. The first and second nodes may terminate the random access procedure based at least in part on receiving the second random access message. ## Claims ### Claim 1 A method for wireless communication, comprising: transmitting, at a first node of a wireless communications system, a first random access message to a second node to initiate a random access procedure based at least in part on the second node being associated with a timing source, wherein the second node is a neighbor of the first node and is different from a parent node of the first node; receiving a second random access message from the second node, the second random access message comprising timing information based at least in part on the timing source; and terminating the random access procedure prior to establishing a connection with the second node via the random access procedure based at least in part on receiving the second random access message. ### Claim 2 (depends on 1) The method of claim 1, wherein terminating the random access procedure further comprises: transmitting a third message to the second node, wherein the third message comprises a request for the termination of the random access procedure. ### Claim 3 (depends on 2) The method of claim 2, further comprising: receiving a control channel message scheduling the third message, wherein cyclic redundancy check (CRC) bits of the control channel message are scrambled by a random access radio network temporary identifier (RNTI) or a temporary cell RNTI. ### Claim 4 (depends on 2) The method of claim 2, wherein the third message comprises one or more of a radio resource control connection request message or a radio resource control connection setup complete message. ### Claim 5 (depends on 1) The method of claim 1, wherein terminating the random access procedure further comprises: receiving a radio resource control connection setup message from the second node; and transmitting an uplink message after receiving the radio resource control connection setup message, wherein the uplink message comprises a request for the termination of the random access procedure. ### Claim 6 (depends on 1) The method of claim 1, wherein transmitting the first random access message further comprises: transmitting the first random access message with a preamble that is associated with the termination of the random access procedure. ### Claim 7 (depends on 1) The method of claim 1, further comprising: receiving an indication of the termination of the random access procedure from the second node, wherein the indication is received via one or more of a downlink control channel associated with the second random access message, a downlink shared channel associated with the second random access message, a downlink control channel associated with a third message, a downlink control channel associated with a fourth message, or a downlink shared channel associated with the fourth message. ### Claim 8 (depends on 7) The method of claim 7, wherein the downlink control channel associated with the second random access message and the downlink shared channel associated with the second random access message are scheduled with a random access radio network temporary identifier (RNTI), the downlink control channel of the third message is scheduled with a temporary cell RNTI, or the downlink control channel of the fourth message and the downlink shared channel of the fourth message are scheduled with the random access RNTI or the temporary cell RNTI. ### Claim 9 (depends on 1) The method of claim 1, wherein cyclic redundancy check (CRC) bits of the second random access message are scrambled by a random access radio network temporary identifier (RNTI). ### Claim 10 (depends on 1) The method of claim 1, further comprising: determining a timing advance command based at least in part on the timing information included in the second random access message. ### Claim 11 (depends on 1) The method of claim 1, further comprising: receiving, from the parent node, a list of nodes associated with a timing synchronization process, wherein the list of nodes comprises the second node, and transmitting the first random access message is based at least in part on the list of nodes. ### Claim 12 (depends on 1) The method of claim 1, further comprising: transmitting an indication to the second node that the first random access message was transmitted to receive the timing information, wherein the random access procedure is terminated based at least in part on transmitting the indication. ### Claim 13 (depends on 1) The method of claim 1, wherein the timing source connected to the second node is a Global Navigation Satellite System (GNSS) source. ### Claim 14 A method for wireless communication, comprising: receiving, at a second node of a wireless communications system, a first random access message initiating a random access procedure from a first node based at least in part on the second node being associated with a timing source, wherein the second node is a neighbor of the first node and is different from a parent node of the first node; retrieving timing information from the timing source based at least in part on the first random access message and the random access procedure; transmitting a second random access message to the first node, the second random access message comprising the timing information from the timing source; and terminating the random access procedure prior to establishing a connection with the first node via the random access procedure based at least in part on transmitting the second random access message comprising the timing information. ### Claim 15 (depends on 14) The method of claim 14, wherein terminating the random access procedure further comprises: receiving a third message from the first node, wherein the third message comprises a request for the termination of the random access procedure. ### Claim 16 (depends on 15) The method of claim 15, further comprising: transmitting a control channel message scheduling the third message, wherein cyclic redundancy check (CRC) bits of the control channel message are scrambled by a random access radio network temporary identifier (RNTI) or a temporary cell RNTI. ### Claim 17 (depends on 15) The method of claim 15, wherein the third message comprises one or more of a radio resource control connection request message or a radio resource control connection setup complete message. ### Claim 18 (depends on 14) The method of claim 14, wherein terminating the random access procedure further comprises: transmitting a radio resource control connection setup message to the first node; and receiving an uplink message from the first node after transmitting the radio resource control connection setup message, wherein the uplink message comprises a request for the termination of the random access procedure. ### Claim 19 (depends on 14) The method of claim 14, wherein receiving the first random access message further comprises: identifying a preamble of the first random access message that is associated with the termination of the random access procedure. ### Claim 20 (depends on 14) The method of claim 14, further comprising: transmitting an indication of the termination of the random access procedure to the first node, wherein the indication is transmitted via one or more of a downlink control channel associated with the second random access message, a downlink shared channel associated with the second random access message, a downlink control channel associated with a third message, a downlink control channel associated with a fourth message, or a downlink shared channel associated with the fourth message. ### Claim 21 (depends on 20) The method of claim 20, wherein the downlink control channel associated with the second random access message and the downlink shared channel associated with the second random access message are scheduled with a random access radio network temporary identifier (RNTI), the downlink control channel of the third message is scheduled with a temporary cell RNTI, or the downlink control channel of the fourth message and the downlink shared channel of the fourth message are scheduled with the random access RNTI or the temporary cell RNTI. ### Claim 22 (depends on 14) The method of claim 14, further comprising: scrambling cyclic redundancy check (CRC) bits of the second random access message with a random access radio network temporary identifier (RNTI). ### Claim 23 (depends on 14) The method of claim 14, further comprising: indicating a timing advance command based at least in part on the timing information included in the second random access message. ### Claim 24 (depends on 14) The method of claim 14, further comprising: receiving an indication from the first node that the first random access message was transmitted to receive the timing information, wherein the random access procedure is terminated based at least in part on transmitting the indication. ### Claim 25 (depends on 14) The method of claim 14, wherein the timing source connected to the second node is a Global Navigation Satellite System (GNSS) source. ### Claim 26 An apparatus for wireless communication, comprising: a processor, memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to: transmit, from a first node of a wireless communications system, a first random access message to a second node to initiate a random access procedure based at least in part on the second node being associated with a timing source, wherein the second node is a neighbor of the first node and is different from a parent node of the first node; receive a second random access message from the second node, the second random access message comprising timing information based at least in part on the timing source; and terminate the random access procedure prior to establishing a connection with the second node via the random access procedure based at least in part on receiving the second random access message. ### Claim 27 (depends on 26) The apparatus of claim 26, wherein the instructions to terminate the random access procedure are further executable by the processor to cause the apparatus to: transmit a third message to the second node, wherein the third message comprises a request for the termination of the random access procedure. ### Claim 28 (depends on 27) The apparatus of claim 27, wherein the instructions are further executable by the processor to cause the apparatus to: receive a control channel message scheduling the third message, wherein cyclic redundancy check (CRC) bits of the control channel message are scrambled by a random access radio network temporary identifier (RNTI) or a temporary cell RNTI. ### Claim 29 An apparatus for wireless communication, comprising: a processor, memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to: receive, at a second node of a wireless communications system, a first random access message initiating a random access procedure from a first node based at least in part on the second node being associated with a timing source, wherein the second node is a neighbor of the first node and is different from a parent node of the first node; retrieve timing information from the timing source based at least in part on the first random access message and the random access procedure; transmit a second random access message to the first node, the second random access message comprising the timing information from the timing source; and terminate the random access procedure prior to establishing a connection with the first node via the random access procedure based at least in part on transmitting the second random access message comprising the timing information. ### Claim 30 (depends on 29) The apparatus of claim 29, wherein the instructions to terminate the random access procedure are further executable by the processor to cause the apparatus to: receive a third message from the first node, wherein the third message comprises a request for the termination of the random access procedure.