# US 11,452,006 B2 · UE based fast return to 5G > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,452,006 B2 - Document ID: US11452006B2 - Status: Granted - Kind: B2 - Application number: 17/053,649 - Filed: 2018-07-26 - Published: 2021-03-11 - Granted: 2022-09-20 - Earliest claimed: 2018-05-28 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Juan Zhang; Xipeng Zhu; Haris Zisimopoulos; Francesco Pica - Web page: https://patentgrep.com/patent/US11452006B2 ## CPC - H04W 76/30: Connection release - H04W 36/00226: {wherein the core network technologies comprise IP multimedia system [IMS], e.g. single radio voice call continuity [SRVCC]} - H04W 36/0085: {Hand-off measurements} - H04W 60/04: using triggered events - H04W 36/00835: {Determination of neighbour cell lists} - H04W 36/1443: {between licensed networks} - H04W 60/00: Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration - 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 present disclosure provide techniques that allow the user equipment (UE) that initiated single radio voice call continuity (SRVCC) handover during an active voice session from 5G new radio (NR) to 3G legacy system to effectively transition back from 3G legacy systems to 5G NR systems after conclusion of the active voice session. In one example, the UE may override radio resource control (RRC) connection release with evolved universal terrestrial radio access network (E-UTRAN) frequency information that may direct the UE to camp in E-UTRAN cell (LTE cell). In another example, the UE, as a local policy or configuration, may override the UTRAN cell information when the UE is registered in next generation radio access network (NR) cell as 5G capable UE. ## Claims ### Claim 1 A method for wireless communications, comprising: determining, at a user equipment (UE), that a voice call over a legacy cell has terminated; receiving, from the legacy cell, a radio resource control (RRC) release message in response to the termination of the voice call; selecting, in response to the RRC release message, a new radio (NR) cell for communication without camping on either the legacy cell or an intermediate cell after the voice call has terminated, wherein selecting the NR cell includes: overriding at least one procedure associated with the RRC release message by ignoring the at least one procedure that includes camping on the legacy cell or the intermediate cell and reading a system information block (SIB) to identify one or more neighboring evolved universal terrestrial radio access network (E-UTRAN) cells, measuring, by the UE, one or more NR frequencies in lieu of camping on the legacy cell, the intermediate cell, or the one or more E-UTRAN cells and selecting the NR cell for communication based on measuring the one or more NR frequencies; and establishing communication with the NR cell based on the selection. ### Claim 2 (depends on 1) The method of claim 1, wherein the legacy cell is one of a universal terrestrial radio access network (UTRAN) cell, a global system for mobile communication (GSM) cell or a CDMA2000 cell, and wherein the intermediate cell is an evolved universal terrestrial radio access network (E-UTRAN) cell. ### Claim 3 (depends on 1) The method of claim 1, wherein the legacy cell comprises a universal terrestrial radio access network (UTRAN) cell, and the (SIB) comprises a UTRAN SIB, and wherein the at least one procedure associated with the RRC release message that is being ignored includes camping on the UTRAN cell to receive the UTRAN SIB for use in identifying one or more neighboring E-UTRAN cells. ### Claim 4 (depends on 1) The method of claim 1, wherein the legacy cell comprises a global system for mobile communication (GSM) EDGE Radio Access Network (GERAN) cell, and the (SIB) comprises a GERAN SIB, and wherein the at least one procedure associated with the RRC release message that is being ignored includes camping on the GERAN cell to receive the GERAN SIB for use in identifying one or more neighboring evolved universal terrestrial radio access network (E-UTRAN) cells. ### Claim 5 (depends on 1) The method of claim 1, wherein the RRC release message includes RRC redirection information that comprises one or both of cell or frequency information associated with an evolved universal terrestrial radio access network (E-UTRAN) cell. ### Claim 6 (depends on 5) The method of claim 5, wherein overriding the at least one procedure associated with the RRC release message comprises: analyzing the one or both of the cell or frequency information associated with the E-UTRAN cell to determine whether there is at least one NR cell near the E-UTRAN cell. ### Claim 7 (depends on 6) The method of claim 6, further comprising: selecting the NR cell based on determining that there is at least one NR cell near the E-UTRAN cell. ### Claim 8 (depends on 6) The method of claim 6, further comprising: determining that there are a plurality of NR cells near the E-UTRAN cell based on analyzing the E-UTRAN cell information; and selecting the NR cell based on priority associated with each of the plurality of NR cells, wherein the selected NR cell has the highest priority. ### Claim 9 (depends on 8) The method of claim 8, wherein the priority associated with each of the plurality of NR cells is included in a E-UTRAN system information. ### Claim 10 (depends on 1) The method of claim 1, wherein overriding the at least one procedure associated with the RRC release message is based on a policy or configuration information associated with UE. ### Claim 11 (depends on 10) The method of claim 10, wherein the policy or the configuration information association with the UE is received by the UE based on the UE registration with the NR cell by non-access stratum (NAS) message during registration procedure. ### Claim 12 (depends on 10) The method of claim 10, wherein the policy or the configuration information association with the UE is received via Open Mobile Alliance (OMA) Device Management (DM) in the NR cell. ### Claim 13 (depends on 10) The method of claim 10, wherein the policy or the configuration information association with the UE is based on a static configuration. ### Claim 14 (depends on 1) The method of claim 1, wherein the RRC release message is a global system for mobile communications (GSM) enhanced data rates for GSM evolution (EDGE) radio access network (GERAN) release. ### Claim 15 An apparatus for wireless communications, comprising: a transceiver; a memory configured to store instructions; a processor communicatively coupled with the transceiver and the memory, wherein the processor is configured to execute the instructions to: determine, at a user equipment (UE), that a voice call over a legacy cell has terminated; receive, from legacy cell via the transceiver, a radio resource control (RRC) release message in response to the termination of the voice call; select, in response to the RRC release message, a new radio (NR) cell for communication without camping on either the legacy cell or an intermediate cell after the voice call has terminated, wherein the selection of the NR cell includes: an override of at least one procedure associated with the RRC release message to ignore the at least one procedure that includes camping on the legacy cell or the intermediate cell and reading a system information block (SIB) to identify one or more neighboring evolved universal terrestrial radio access network (E-UTRAN) cells, a measure of one or more NR frequencies in lieu of camping on the legacy cell, the intermediate cell, or the one or more E-UTRAN cells and selecting the NR cell for communication based on measuring the one or more NR frequencies; and establish, via the transceiver, communication with the NR cell based on the selection. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein the legacy cell is one of a universal terrestrial radio access network (UTRAN) cell, a global system for mobile communication (GSM) cell or a CDMA2000 cell, and wherein the intermediate cell is an evolved universal terrestrial radio access network (E-UTRAN) cell. ### Claim 17 (depends on 15) The apparatus of claim 15, wherein the legacy cell comprises a universal terrestrial radio access network (UTRAN) cell, and the (SIB) comprises a UTRAN SIB, and wherein the processor configured to execute the instructions to override the at least one procedure associated with the RRC release message further includes instructions to: ignore at least one procedure the procedures associated with the RRC release message that includes camping on the UTRAN cell to receive the UTRAN SIB for use in identifying one or more neighboring E-UTRAN cells. ### Claim 18 (depends on 15) The apparatus of claim 15, wherein the legacy cell comprises a global system for mobile communication (GSM) EDGE Radio Access Network (GERAN) cell, and the (SIB) comprises a GERAN SIB, and wherein the processor configured to execute the instructions to override the at least one procedure associated with the RRC release message further includes instructions to: ignore at least one procedure associated with the RRC release message that includes camping on the GERAN cell to receive the GERAN SIB for use in identifying one or more neighboring E-UTRAN cells. ### Claim 19 (depends on 15) The apparatus of claim 15, wherein the RRC release message includes RRC redirection information that comprises one or both of cell or frequency information associated with an evolved universal terrestrial radio access network (E-UTRAN) cell. ### Claim 20 (depends on 19) The apparatus of claim 19, wherein the processor configured to execute the instructions to override the at least one procedure associated with the RRC release message further includes instructions to: analyze the one or both of the cell or frequency information associated with the E-UTRAN cell to determine whether there is at least one NR cell near the E-UTRAN cell. ### Claim 21 (depends on 20) The apparatus of claim 20, wherein the processor is further configured to execute the instructions to: select the NR cell based on determining that there is at least one NR cell near the E-UTRAN cell. ### Claim 22 (depends on 20) The apparatus of claim 20, wherein the processor is further configured to execute the instructions to: determine that there are a plurality of NR cells near the E-UTRAN cell based on analyzing the E-UTRAN cell information; and select the NR cell based on priority associated with each of the plurality of NR cells, wherein the selected NR cell has the highest priority. ### Claim 23 (depends on 22) The apparatus of claim 22, wherein the priority associated with each of the plurality of NR cells is included in a E-UTRAN system information. ### Claim 24 (depends on 15) The apparatus of claim 15, wherein overriding the at least one procedure associated with the RRC release message is based on a policy or configuration information associated with UE. ### Claim 25 (depends on 24) The apparatus of claim 24, wherein the policy or the configuration information association with the UE is received by the UE based on the UE registration with the NR cell by non-access stratum (NAS) message during registration procedure. ### Claim 26 (depends on 24) The apparatus of claim 24, wherein the policy or the configuration information association with the UE is received via Open Mobile Alliance (OMA) Device Management (DM) in the NR cell. ### Claim 27 (depends on 24) The apparatus of claim 24, wherein the policy or the configuration information association with the UE is based on a static configuration. ### Claim 28 An article of manufacture, comprising: a non-transitory computer readable medium having stored therein instructions implementable by one or more processors of a user equipment (UE) to: determine that a voice call over a legacy cell has terminated; receive, from the legacy cell, a radio resource control (RRC) release message in response to the termination of the voice call; select, in response to the RRC release message, a new radio (NR) cell for communication without camping on either the legacy cell or an intermediate cell after the voice call has terminated, wherein the selection of the NR cell includes: an override of overriding at least one procedure associated with the RRC release message to ignore the at least one procedure that includes camping on the legacy cell or the intermediate cell and reading a system information block (SIB) to identify one or more neighboring evolved universal terrestrial radio access network (E-UTRAN) cells, measuring, by the UE, one or more NR frequencies in lieu of camping on the legacy cell, the intermediate cell, or the one or more E-UTRAN cells and selecting the NR cell for communication based on measuring the one or more NR frequencies; and establishing communication with the NR cell based on the selection.