UE Return to First RAT After SRVCC Call Continuity
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Solution Overview
Problem
Wireless communication systems face challenges in maintaining call continuity and efficiently returning to a first radio access technology (RAT) network after a call in a second RAT network, particularly due to lack of direct mechanisms for redirection from legacy Universal Terrestrial Radio Access (UTRA) to New Radio (NR) networks, leading to suboptimal performance and user experience.
Innovation Solution
The implementation of techniques that allow user equipment (UE) to actively seek and camp on suitable NR cells by obtaining information from system information blocks (SIBs) broadcast in LTE or UTRA, enabling faster return to NR after a Single Radio Voice Call Continuity (SRVCC) procedure in UTRA, without requiring two active radios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UE moves from first RAT to second RAT to maintain call continuity, then call continuity is improved, but time to return to first RAT after call ends deteriorates
Solution Approach 1:
The patent applies preliminary action by having the UE perform measurements and obtain system information about the first RAT network while camped on the second RAT network before the call actually needs to return. The UE proactively acquires necessary information and performs preliminary actions so that when the call ends, the return to the first RAT can be executed immediately without delay, thus resolving the contradiction between maintaining call continuity and quickly returning to the preferred network.
2Reliability
If UE performs full scan for first RAT cells after call ends, then return to first RAT is achieved, but power consumption increases
Solution Approach 1:
The patent applies preliminary action by having the UE perform measurements and obtain system information about the first RAT network while camped on the second RAT network before the call actually needs to return. The UE proactively acquires necessary information and performs preliminary actions so that when the call ends, the return to the first RAT can be executed immediately without delay, thus resolving the contradiction between maintaining call continuity and quickly returning to the preferred network.
Solution Approach 2:
The patent applies self-service by utilizing the UE's existing radio resources and processing capabilities to perform measurements and obtain system information autonomously while camped on the second RAT network. The UE leverages its own resources rather than requiring external assistance or additional dedicated resources, thereby reducing overall power consumption while still achieving reliable return to the first RAT network.
3Use of energy by moving object
If UE uses existing radio resources for measurements, then power consumption is reduced, but measurement accuracy may deteriorate
Solution Approach 1:
The patent applies partial action by having the UE perform selective measurements and obtain only the necessary system information required for the return to the first RAT network. Rather than performing comprehensive measurements of all possible parameters, the UE focuses on acquiring the essential information needed for successful network return, thereby reducing power consumption while maintaining sufficient measurement accuracy for the intended purpose.
Data Source
AI summary
Certain aspects of the present disclosure provide a technique for wireless communications by a user equipment (UE). The UE moves from a first radio access technology (RAT) to a second RAT to maintain continuity of a call and takes one or more actions involving a third RAT to speed a return to the first RAT after the call has ended in the second RAT.