MME CSFB Request Conflict Resolution

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Solution Overview

Problem

The existing LTE network architecture faces challenges in managing circuit switched fallback (CSFB) requests, particularly in scenarios where both mobile originated (MO) and mobile terminated (MT) CSFB requests are simultaneous, leading to potential conflicts and unclear behavior among network nodes due to lack of specified conflict resolution strategies.

Innovation Solution

The proposed solution involves a mobile management entity (MME) detecting pending CSFB requests and communicating instructions to a wireless transmit/receive unit (WTRU) and other network entities to manage these requests, including generating messages for CSFB procedures and handling simultaneous MO and MT CSFB requests through specific message flows and priority determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the network runs both circuit-switched and packet-switched systems concurrently to support legacy devices, then compatibility with existing devices is improved, but system complexity increases

Engineering Contradiction:

Improvedevice compatibilityVSAvoidnetwork architecture complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The MME acts as an intermediary entity that manages CSFB requests by detecting pending requests, generating appropriate messages, and coordinating between the packet-switched LTE network and circuit-switched legacy networks. This mediator approach allows the network to support both circuit-switched and packet-switched devices concurrently without requiring full dual-network operation, thereby improving device compatibility while controlling network architecture complexity through centralized management

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the MME detects and manages pending CSFB requests with conflict resolution strategies, then reliability of CSFB processes is improved, but device complexity increases

Engineering Contradiction:

ImproveCSFB process reliabilityVSAvoidMME management complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The MME performs preliminary detection of pending CSFB requests before conflicts occur. By detecting pending requests in advance and generating appropriate management messages proactively, the system resolves potential race conditions before they manifest as reliability issues. This preliminary action approach improves CSFB process reliability while managing MME complexity through preventive rather than reactive measures

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10945302B2Managing race conditions between circuit switched fallback requests

Publication Date: 2021.03.09 INTERDIGITAL PATENT HOLDINGS INC

AI summary

Circuit switched fallback (CSFB) requests may be managed. A mobile management entity (MME) can detect one or more pending CSFB requests. In response to detecting the pending CSFB request(s), the MME can generate a message that indicates the one or more pending CSFB requests, and can communicate the message to one of a mobile switching center (MSC) and a virtual location register (VLR).