Autonomous LTE Return After Circuit-Switched Fallback
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently transitioning user equipment (UE) from a 2G/3G network back to an LTE network after a circuit-switched fallback (CSFB) call, particularly when standards-based mechanisms are not supported, are delayed, or hindered by ongoing packet data activity.
Innovation Solution
The UE autonomously determines the end of a CSFB call and initiates actions to return to the LTE network by sending a Signaling Connection Release Indication (SCRI) message, followed by cell selection procedures optimized for LTE service, even in the absence of network confirmation or with ongoing data activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE waits for network confirmation to return to LTE network after CSFB call, then the network can control the transition, but the return process is delayed and service disruption increases
Solution Approach 1:
The UE performs preliminary actions by autonomously determining call termination and initiating return to LTE network before receiving explicit network confirmation. The UE sends SCRI message and executes cell selection procedures proactively, rather than passively waiting for network instructions, thereby reducing the time loss while maintaining transition reliability through proper signaling protocols.
2Ease of manufacture
If the UE uses standard mobility mechanisms to return to LTE network, then the process is standardized, but the mechanisms are delayed or hindered by ongoing packet data activity
Solution Approach 1:
The UE performs self-service by autonomously detecting call termination conditions and initiating return to LTE network independently of network control. The UE monitors its own state, determines when to trigger return procedures, and executes cell selection without waiting for network commands, thereby improving transition efficiency while following standardized protocols.
Solution Approach 2:
The UE takes preliminary actions by proactively initiating the return to LTE network procedure before standard mobility mechanisms would naturally trigger it. By sending SCRI messages and starting cell selection procedures in advance, the UE overcomes delays caused by ongoing packet data activity and accelerates the transition process.
3Duration of action of stationary object
If the UE remains on 2G/3G network after CSFB call, then packet data activity can continue uninterrupted, but the UE cannot leverage LTE's higher data rates
Solution Approach 1:
The UE performs preliminary actions by initiating return to LTE network procedures while still on the 2G/3G network, before packet data activity completely terminates. This allows the UE to establish LTE connection in advance and resume data transmission at higher rates sooner, minimizing the duration of low-rate operation while ensuring continuous service availability.
Data Source
AI summary
Certain aspects of the present disclosure relate to techniques for improving a circuit-switched fallback (CSFB) user experience. In aspects, methods and systems for autonomously returning a user equipment (UE) from a 2G (2nd generation)/3G (3rd generation) network to an LTE (Long Term Evolution) network are provided. The UE may store a flag to note whether a current circuit switched (CS) call in the 2G/3G network is a result of a CSFB. The UE, in response to detecting a termination of the current CS call in the 2G/3G network and determining that the terminated call was a CSFB call (e.g., from the status of the flag), may trigger a mobility mechanism to autonomously return the UE to the LTE network.