5G NR Voice Fallback Mobility Command Indication
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Solution Overview
Problem
In 5G NR deployments, voice calls may experience delays and performance degradation due to a lack of awareness by target base stations about the purpose of handovers or redirections during voice fallback procedures from 5G NR to other radio access technologies like LTE or 3G, leading to inadequate radio resource allocation and failed connections.
Innovation Solution
The source base station transmits a command of mobility with a voice fallback indication to both the user equipment (UE) and the target base station, ensuring that the target station prioritizes radio resources for voice calls and the UE knows to reattempt connections if the initial handover fails, thereby optimizing voice call setup and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a handover or redirection command is transmitted during voice fallback from 5G NR to other RATs, then the UE can be directed to a target base station, but the target base station lacks awareness of the voice fallback purpose leading to inadequate radio resource allocation
Solution Approach 1:
The source base station performs preliminary action by including a voice fallback indication in the handover or redirection command before the UE executes the handover. This ensures that the target base station is pre-informed about the voice fallback purpose, allowing it to prepare appropriate radio resource allocation in advance, thus preventing information loss and improving call establishment reliability.
2Productivity
If the target base station is not informed about voice fallback purpose, then the handover procedure is simpler, but radio resource allocation is inadequate causing delays and performance degradation
Solution Approach 1:
The voice fallback indication is included in the handover command transmitted by the source base station before the handover executes. This preliminary information provision enables the target base station to prioritize radio resource allocation for voice traffic, reducing setup delays and improving call establishment speed without adding significant procedural complexity.
3Reliability
If the UE does not know to reattempt connections on failure, then the protocol is simpler, but voice call establishment fails due to inadequate failover strategies
Solution Approach 1:
The voice fallback indication provides feedback information to the UE about the purpose of the handover. Based on this feedback, the UE can implement appropriate failover strategies by reattempting connections if the initial handover fails, thus improving procedure reliability without significantly increasing device complexity.
Data Source
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AI summary
This disclosure provides systems, methods, apparatuses and computer-readable medium for wireless communication. In some aspects, a user equipment (UE) may receive, from a first base station (BS) associated with a fifth generation New Radio (5G NR) radio access technology (RAT), a command of mobility from the 5G NR RAT to a second RAT. The UE may determine that the command of mobility is for voice fallback. The UE may transmit, to a second BS associated with the second RAT and based at least in part on determining that the command of mobility is for voice fallback, a radio resource control (RRC) connection request communication for attempting to communicatively connect with the second BS for voice fallback.