Resource Release Logic for Circuit-Switched Fallback in Wireless Networks
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Solution Overview
Problem
In cellular wireless networks, the inefficient release of resources allocated to user equipment devices (UEs) during circuit-switched-fallback (CSFB) calls leads to resource reservation for longer than necessary or premature release, causing inefficiencies, especially when UEs transition back to the original network without completing the CSFB call setup.
Innovation Solution
A method where the first network allocates resources to a UE, signals for CSFB call setup, and only releases these resources after receiving a notification that the CSFB call setup is complete, ensuring resources are reserved if the call is canceled or rejected, and avoiding unnecessary resource reservation after successful call setup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the first network releases resources immediately when UE transitions to the second network for CSFB call setup, then resource availability for other UEs is improved, but resources may be prematurely released if the UE transitions back before call setup completes
Solution Approach 1:
The first network receives feedback in the form of a notification message from the second network indicating whether CSFB call setup was successful. Based on this feedback, the first network decides whether to release the allocated resources. If call setup failed and UE transitioned back, resources are retained. If call setup succeeded, resources are released. This feedback mechanism resolves the contradiction by making resource release contingent on actual call setup outcomes.
Solution Approach 2:
The first network performs preliminary resource allocation to the UE before the UE actually needs them for CSFB call setup. The resources are allocated in advance and held in a reserved state until the call setup outcome is known. This preliminary action ensures resources are available when needed while allowing for later release if the call setup succeeds, thus improving both resource availability and retention reliability.
2Reliability
If the first network retains resources after UE transitions to the second network, then resources are available for UE return, but resource waste occurs when CSFB call setup succeeds
Solution Approach 1:
The notification message from the second network provides critical feedback about call setup success. When the message indicates successful call setup, the first network releases the retained resources, eliminating waste. When the message indicates failed setup or UE return, resources are retained for potential reuse. This feedback-driven approach resolves the contradiction between retention reliability and energy efficiency.
Solution Approach 2:
The resource allocation state is made dynamic rather than static. Resources transition between three states: allocated (before CSFB), retained (during CSFB setup), and released (after successful setup or UE return). This dynamic state management allows the system to adapt resource retention to actual call setup outcomes, preventing waste while maintaining reliability during the transition period.
3Productivity
If the first network waits for notification before releasing resources, then resource release timing is optimized, but system complexity increases due to inter-network signaling
Solution Approach 1:
The notification message mechanism serves multiple functions: it informs the first network of call setup completion, triggers resource release decisions, and coordinates inter-network state synchronization. By making this signaling mechanism multi-functional, the patent reduces the need for separate dedicated resource release signaling, thereby optimizing resource management efficiency while minimizing the increase in signaling complexity.
Data Source
AI summary
A method and system to help manage resources in a fallback scenario is disclosed. A first network may be configured to serve user equipment devices (UEs) according to a first protocol and a second network may be configured to serve UEs according to a second protocol. The method may involve the first network serving a UE, where serving the UE includes allocating at least one resource to the UE. The method may also involve, after the UE has transitioned from being served by the first network to being served by the second network for a circuit-switched-fallback call, (i) if the UE completes call setup, the first network releasing the resources, but (ii) if the UE does not complete call setup, the first network using the allocated resources to serve the UE after the UE transitions back to being served by the first network.