# US 11,910,457 B2 · Unicast sidelink access stratum level connection maintenance > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,910,457 B2 - Document ID: US11910457B2 - Status: Granted - Kind: B2 - Application number: 16/739,952 - Filed: 2020-01-10 - Published: 2020-08-06 - Granted: 2024-02-20 - Earliest claimed: 2019-01-31 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Yuqin Chen; Murtaza A. Shikari; Sree Ram Kodali; Srirang A. Lovlekar; Sethuraman Gurumoorthy; Haitong Sun; Fangli Xu; Haijing Hu; Dawei Zhang; Srinivasan Nimmala; Longda Xing; Xu Ou - Web page: https://patentgrep.com/patent/US11910457B2 ## CPC - H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)} - H04W 76/18: Management of setup rejection or failure - H04L 1/0026: {Transmission of channel quality indication} - H04L 5/0055: {Physical resource allocation for ACK/NACK (for physical mapping arrangements in ARQ protocols H04L1/1861)} - H04L 5/006: {Quality of the received signal, e.g. BER, SNR, water filling} - H04W 4/40: for vehicles, e.g. vehicle-to-pedestrians [V2P] - H04W 4/44: for communication between vehicles and infrastructures, e.g. vehicle-to-cloud [V2C] or vehicle-to-home [V2H] - H04W 4/46: for vehicle-to-vehicle communication [V2V] - H04W 24/08: Testing, {supervising or monitoring} using real traffic - H04W 76/19: Connection re-establishment - H04W 76/23: Manipulation of direct-mode connections - H04W 76/25: Maintenance of established connections - H04W 76/27: Transitions between radio resource control [RRC] states - H04W 80/08: Upper layer protocols {(network arrangements or communication protocols for networked applications H04L67/00)} - H04W 4/027: {using movement velocity, acceleration information} - H04W 76/40: for selective distribution or broadcast - H04W 92/18: between terminal devices - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Embodiments are presented herein of apparatuses, systems, and methods for performing unicast sidelink access stratum level connection maintenance. A first wireless device and a second wireless device may establish a unicast sidelink wireless connection. One or both of the first wireless device and the second wireless device may perform access stratum level connection maintenance on the unicast sidelink wireless connection. This may include performing any or all of radio link monitoring, radio resource management, or physical layer based link quality detection. The access stratum and the non-access stratum of each device may also communicate with each other regarding either or both of link quality or link status of the unicast sidelink wireless connection. ## Claims ### Claim 1 An apparatus, comprising: a memory; and a processor in communication with the memory and configured to cause a first wireless device to: establish a unicast sidelink wireless connection with a second wireless device; and perform access stratum measurements for the unicast sidelink wireless connection, wherein to perform the access stratum measurements for the unicast sidelink wireless connection, the first wireless device is further configured to: measure a plurality of characteristics of the unicast sidelink wireless connection, wherein the plurality of characteristics of the unicast sidelink wireless connection include at least a sidelink reference signal received power (SL RSRP); and provide a measurement report to the second wireless device based at least in part on measuring the plurality of characteristics of the unicast sidelink wireless connection; receive, by an access stratum layer of the first wireless device, an indication from an upper layer of the first wireless device that the unicast sidelink wireless connection with the second wireless device has been released at the upper layer of the first wireless device; and release a radio resource control connection of the unicast sidelink wireless connection with the second wireless device based at least in part on the indication from the upper layer of the first wireless device. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to cause the first wireless device to: receive an indication to reconfigure the unicast sidelink wireless connection from the second wireless device based at least in part on the measurement report. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the indication to reconfigure the unicast sidelink wireless connection indicates to perform one or more of: switching the unicast sidelink wireless connection to a different frequency; modifying a configured number of re-transmissions for the unicast sidelink wireless connection; modifying a modulation and coding scheme for the unicast sidelink wireless connection; switching a data radio bearer of the unicast sidelink wireless connection to a different carrier; modifying a packet data convergence protocol (PDCP) duplication configuration of a data radio bearer of the unicast sidelink wireless connection; or changing a resource pool for the unicast sidelink wireless connection. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to cause the first wireless device to: receive a second measurement report from the second wireless device; and determine to modify a configured transmission power for the unicast sidelink wireless connection based at least in part on the second measurement report received from the second wireless device. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to cause the first wireless device to: provide an indication of a link status of the unicast sidelink wireless connection with the second wireless device from an access stratum layer of the first wireless device to an upper layer of the first wireless device. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the measurement report causes modification by the second wireless device of a transmission power for the unicast sidelink wireless connection. ### Claim 7 A first wireless device, comprising: a radio; a processor operably coupled to the radio, wherein the first wireless device is configured to: establish a unicast sidelink wireless connection with a second wireless device; and perform access stratum measurements for the unicast sidelink wireless connection, wherein to perform the access stratum measurements for the unicast sidelink wireless connection, the first wireless device is further configured to: measure a plurality of characteristics of the unicast sidelink wireless connection, wherein the plurality of characteristics of the unicast sidelink wireless connection include at least a sidelink reference signal received power (SL RSRP); and provide a measurement report to the second wireless device based at least in part on measuring the plurality of characteristics of the unicast sidelink wireless connection; receive, by an access stratum layer of the first wireless device, an indication from an upper layer of the first wireless device that the unicast sidelink wireless connection with the second wireless device has been released at the upper layer of the first wireless device; and release a radio resource control connection of the unicast sidelink wireless connection with the second wireless device based at least in part on the indication from the upper layer of the first wireless device. ### Claim 8 (depends on 7) The first wireless device of claim 7, wherein the first wireless device is further configured to: receive an indication to reconfigure the unicast sidelink wireless connection from the second wireless device based at least in part on the measurement report. ### Claim 9 (depends on 8) The first wireless device of claim 8, wherein the indication to reconfigure the unicast sidelink wireless connection indicates to perform one or more of: switching the unicast sidelink wireless connection to a different frequency; modifying a configured number of re-transmissions for the unicast sidelink wireless connection; modifying a modulation and coding scheme for the unicast sidelink wireless connection; switching a data radio bearer of the unicast sidelink wireless connection to a different carrier; modifying a packet data convergence protocol (PDCP) duplication configuration of a data radio bearer of the unicast sidelink wireless connection; or changing a resource pool for the unicast sidelink wireless connection. ### Claim 10 (depends on 7) The first wireless device of claim 7, wherein the first wireless device is further configured to: provide an indication of a link status of the unicast sidelink wireless connection with the second wireless device from an access stratum layer of the first wireless device to an upper layer of the first wireless device. ### Claim 11 (depends on 7) The first wireless device of claim 7, wherein the measurement report causes modification by the second wireless device of a configured transmission power for the unicast sidelink wireless connection. ### Claim 12 A method for operating a first wireless device, the method comprising: establishing a unicast sidelink wireless connection with a second wireless device; and performing access stratum measurements for the unicast sidelink wireless connection, wherein performing the access stratum measurements for the unicast sidelink wireless connection comprises: measuring a plurality of characteristics of the unicast sidelink wireless connection, wherein the plurality of characteristics of the unicast sidelink wireless connection include at least a sidelink reference signal received power (SL RSRP); and providing a measurement report to the second wireless device based at least in part on measuring the plurality of characteristics of the unicast sidelink wireless connection; receiving an indication from an upper layer of the first wireless device that the unicast sidelink wireless connection with the second wireless device has been released at the upper layer of the first wireless device; and releasing a radio resource control connection of the unicast sidelink wireless connection with the second wireless device based at least in part on the indication from the upper layer of the first wireless device. ### Claim 13 (depends on 12) The method of claim 12, the method further comprising: receiving an indication to reconfigure the unicast sidelink wireless connection from the second wireless device based at least in part on the measurement report. ### Claim 14 (depends on 13) The method of claim 13, wherein the indication to reconfigure the unicast sidelink wireless connection indicates to perform one or more of: switching the unicast sidelink wireless connection to a different frequency; modifying a configured number of re-transmissions for the unicast sidelink wireless connection; modifying a modulation and coding scheme for the unicast sidelink wireless connection; switching a data radio bearer of the unicast sidelink wireless connection to a different carrier; modifying a packet data convergence protocol (PDCP) duplication configuration of a data radio bearer of the unicast sidelink wireless connection; or changing a resource pool for the unicast sidelink wireless connection. ### Claim 15 (depends on 12) The method of claim 12, the method further comprising: receiving a second measurement report from the second wireless device; and determining to modify a configured transmission power for the unicast sidelink wireless connection based at least in part on the second measurement report received from the second wireless device. ### Claim 16 (depends on 12) The method of claim 12, the method further comprising: providing an indication of a link status of the unicast sidelink wireless connection with the second wireless device to an upper layer of the first wireless device. ### Claim 17 (depends on 12) The method of claim 12, wherein the measurement report causes modification by the second wireless device of a transmission power for the unicast sidelink wireless connection. ### Claim 18 (depends on 5) The apparatus of claim 5, wherein the indication of the link status indicates that the unicast sidelink wireless connection with the second wireless device cannot support data exchange. ### Claim 19 (depends on 10) The first wireless device of claim 10, wherein the indication of the link status indicates that the unicast sidelink wireless connection with the second wireless device cannot support data exchange. ### Claim 20 (depends on 16) The method of claim 16, wherein the indication of the link status indicates that the unicast sidelink wireless connection with the second wireless device cannot support data exchange.