# US 2023/0054886 A1 · FLEXIBLE VOICE OVER WIFI (VoWiFi) HANDOVER TO CELLULAR > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0054886 A1 - Document ID: US20230054886A1 - Status: Published application - Kind: A1 - Application number: 17/407,938 - Filed: 2021-08-20 - Published: 2023-02-23 - Earliest claimed: 2021-08-20 - Assignees: T-Mobile USA, Inc. - Applicants: T-Mobile USA, Inc. - Inventors: Lin Zhang - Web page: https://patentgrep.com/patent/US20230054886A1 ## CPC - H04W 36/00837: {Determination of triggering parameters for hand-off} - H04W 36/0058: {Transmission of hand-off measurement information, e.g. measurement reports} - H04W 36/0079: {in case of hand-off failure or rejection} - H04W 36/1446: {wherein at least one of the networks is unlicensed} - H04W 28/0268: {using specific QoS parameters for wireless networks, e.g. QoS class identifier [QCI] or guaranteed bit rate [GBR] (negotiating SLA or negotiating QoS H04W28/24)} - H04W 36/00226: {wherein the core network technologies comprise IP multimedia system [IMS], e.g. single radio voice call continuity [SRVCC]} - H04W 36/302: {due to low signal strength} - H04W 36/36: by user or terminal equipment - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A flexible solution for handling WiFi to cellular (W2C) handover (e.g., for voice over WiFi (VoWiFi) or video calls) includes: determining, for a wireless network, at least one live conversation performance indicator; based on the at least one live conversation performance indicator, determining at least one W2C handover parameter of a set of W2C handover parameters, the set of W2C handover parameters including a first W2C handover parameter indicating a first trigger condition and a second W2C handover parameter indicating a second trigger condition; and transmitting, by the wireless network, to a user equipment (UE), the at least one W2C handover parameter. In some examples, the W2C handover parameters include a reference signal receive power (RSRP) threshold and/or a received signal strength indication (RSSI) threshold. In some examples, live conversation performance indicators may include a cellular call drop rate, a WiFi call drop rate, and a handover failure rate. ## Claims ### Claim 1 A method of wireless communication, the method comprising: determining, for a wireless network, at least one live conversation performance indicator; based on the at least one live conversation performance indicator, determining at least one WiFi to cellular (W2C) handover parameter of a set of W2C handover parameters, the set of W2C handover parameters including a first W2C handover parameter indicating a first trigger condition and a second W2C handover parameter indicating a second trigger condition; and transmitting, by the wireless network, to a user equipment (UE), the at least one W2C handover parameter. ### Claim 2 (depends on 1) The method of claim 1, further comprising: performing, by the wireless network, a W2C handover of a live conversation session in accordance with the set of W2C handover parameters. ### Claim 3 (depends on 2) The method of claim 2, wherein the live conversation session comprises a voice call or a video call. ### Claim 4 (depends on 1) The method of claim 1, wherein determining at least one live conversation performance indicator comprises: determining at least one live conversation performance indicator for a live conversation session over cellular and determining at least one live conversation performance indicator for a live conversation session over WiFi; wherein determining at least one W2C handover parameter comprises: determining the first W2C handover parameter and determining the second W2C handover parameter; and wherein transmitting the at least one W2C handover parameter comprises: transmitting the first W2C handover parameter and transmitting the second W2C handover parameter. ### Claim 5 (depends on 1) The method of claim 1, wherein the at least one live conversation performance indicator is selected from the list consisting of: a cellular call drop rate, a WiFi call drop rate, and a handover failure rate. ### Claim 6 (depends on 1) The method of claim 1, wherein the set of W2C handover parameters includes at least a reference signal receive power (RSRP) threshold and/or a received signal strength indication (RSSI) threshold. ### Claim 7 (depends on 1) The method of claim 1, wherein the set of W2C handover parameters is specific to at least one factor selected from the list consisting of: a cellular technology generation, a model of the UE, and whether a dedicated bearer or quality of service (QoS) flow is already in use for a live conversation session. ### Claim 8 A system for wireless communication, the system comprising: a processor; and a computer-readable medium storing instructions that are operative upon execution by the processor to: determine, for a wireless network, at least one live conversation performance indicator; based on the at least one live conversation performance indicator, determine at least one WiFi to cellular (W2C) handover parameter of a set of W2C handover parameters, the set of W2C handover parameters including a first W2C handover parameter indicating a first trigger condition and a second W2C handover parameter indicating a second trigger condition; and transmit, by the wireless network, to a user equipment (UE), the at least one W2C handover parameter. ### Claim 9 (depends on 8) The system of claim 8, wherein the instructions are further operative to: perform, by the wireless network, a W2C handover of a live conversation session in accordance with the set of W2C handover parameters. ### Claim 10 (depends on 9) The system of claim 9, wherein the live conversation session comprises a voice call or a video call. ### Claim 11 (depends on 8) The system of claim 8, wherein determining at least one live conversation performance indicator comprises: determining at least one live conversation performance indicator for a live conversation session over cellular and determining at least one live conversation performance indicator for a live conversation session over WiFi; wherein determining at least one W2C handover parameter comprises: determining the first W2C handover parameter and determining the second W2C handover parameter; and wherein transmitting the at least one W2C handover parameter comprises: transmitting the first W2C handover parameter and transmitting the second W2C handover parameter. ### Claim 12 (depends on 8) The system of claim 8, wherein the at least one live conversation performance indicator is selected from the list consisting of: a cellular call drop rate, a WiFi call drop rate, handover call drop rate, and a handover failure rate. ### Claim 13 (depends on 8) The system of claim 8, wherein the set of W2C handover parameters includes at least a reference signal receive power (RSRP) threshold and/or a received signal strength indication (RSSI) threshold. ### Claim 14 (depends on 8) The system of claim 8, wherein the set of W2C handover parameters is specific to at least one factor selected from the list consisting of: a cellular technology generation, a model of the UE, and whether a dedicated bearer or quality of service (QoS) flow is already in use for a live conversation session. ### Claim 15 One or more computer storage devices having computer-executable instructions stored thereon, which, upon execution by a computer, cause the computer to perform operations comprising: determining, for a wireless network, at least one live conversation performance indicator; based on the at least one live conversation performance indicator, determining at least one WiFi to cellular (W2C) handover parameter of a set of W2C handover parameters, the set of W2C handover parameters including a first W2C handover parameter indicating a first trigger condition and a second W2C handover parameter indicating a second trigger condition; and transmitting, by the wireless network, to a user equipment (UE), the at least one W2C handover parameter. ### Claim 16 (depends on 15) The one or more computer storage devices of claim 15, wherein the operations further comprise: performing, by the wireless network, a W2C handover of a live conversation session in accordance with the set of W2C handover parameters. ### Claim 17 (depends on 16) The one or more computer storage devices of claim 16, wherein the live conversation session comprises a voice call or a video call. ### Claim 18 (depends on 15) The one or more computer storage devices of claim 15, wherein determining at least one live conversation performance indicator comprises: determining at least one live conversation performance indicator for a live conversation session over cellular and determining at least one live conversation performance indicator for a live conversation session over WiFi; wherein determining at least one W2C handover parameter comprises: determining the first W2C handover parameter and determining the second W2C handover parameter; and wherein transmitting the at least one W2C handover parameter comprises: transmitting the first W2C handover parameter and transmitting the second W2C handover parameter. ### Claim 19 (depends on 15) The one or more computer storage devices of claim 15, wherein the at least one live conversation performance indicator is selected from the list consisting of: a cellular call drop rate, a WiFi call drop rate, and a handover failure rate. ### Claim 20 (depends on 15) The one or more computer storage devices of claim 15, wherein the set of W2C handover parameters includes at least a reference signal receive power (RSRP) threshold and/or a received signal strength indication (RSSI) threshold.