Emergency Call Setup via Cell-Level Location in CSFB
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Solution Overview
Problem
In current communications networks, the selection of an emergency center during circuit switched fallback (CSFB) is inefficient due to the use of relatively coarse RNC ID granularity, leading to prolonged emergency call setup times and poor user experience.
Innovation Solution
The method involves the mobility management entity (MME) sending a handover request message with cell information to the mobile switching center (MSC), allowing the MSC to quickly select an appropriate emergency center by using this cell information, thereby reducing the time required to set up an emergency call.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If RNC ID is used for emergency center selection, then the selection process is simple, but the selection range is too large leading to multiple possible emergency centers and prolonged setup time
Solution Approach 1:
The patent segments the location identification from coarse-grained RNC ID to fine-grained cell ID. By dividing the location information into more granular cell-level data, the system can pinpoint the exact location of the UE, thereby selecting the appropriate emergency center more quickly and accurately without increasing overall system complexity.
Solution Approach 2:
The patent introduces a new dimension of location precision by transitioning from network-level identification (RNC ID) to cell-level identification (cell ID). This dimensional change in location granularity enables faster and more accurate emergency center selection, resolving the contradiction between simplicity and speed.
2Measurement precision
If cell information is included in handover request messages, then emergency center selection accuracy improves, but message complexity increases
Solution Approach 1:
The patent applies preliminary action by obtaining cell information in advance during the handover preparation phase. The MME retrieves cell details before initiating the emergency call setup, so that when emergency center selection is needed, the precise location data is already available. This eliminates the need for complex real-time queries and simplifies the overall message structure.
Solution Approach 2:
The MME acts as an intermediary that pre-processes and stores cell information. Instead of requiring complex direct queries between network elements for location data, the MME mediates by having already retrieved and stored the necessary cell information, simplifying the data exchange process.
Data Source
AI summary
The present application discloses an emergency center selection method, device, and system. The method includes: receiving, by an MME, a request message initiated by UE located in an LTE network for CSFB of an emergency call, and sending, to an eNB, a first notification message that carries an emergency call indication; and sending, to an MSC, a first handover request message that carries information about a cell of a 3G network or information about a cell that is of the LTE network and on which the UE currently camps, so that after the MSC receives the first handover request message, the MSC may select an emergency center according to the information about the cell of the 3G network or the information about the cell of the LTE network in the first handover request message, and further quickly set up a call connection between the UE and the emergency center.