Video Telephony Call Setup via 3G Cell Selection
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Solution Overview
Problem
In LTE mobile communication systems, video telephony services often experience call setup failures or service quality degradation due to the UE being switched to networks that do not support the required data rate for video telephony, such as 2G networks with insufficient data transmission resources.
Innovation Solution
A method and apparatus that prioritize switching the UE to a 3G network for video telephony by transmitting specific call setup requests, measurement reports, and switching commands, ensuring that only 3G cells are considered for measurement and switching, thereby preventing connections to 2G networks that lack sufficient resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the UE is switched to a 2G network for video telephony, then the call setup process is simplified, but the service quality degrades due to insufficient data rate
Solution Approach 1:
The patent changes the network selection parameter from generic CSFB to service-specific CSFB with video telephony indicators. The MME and eNB use specific message types (Extended Service Request, CSFB Execution Command with video indicator) to identify video telephony calls and prevent switching to 2G networks, thereby maintaining service quality while keeping the call setup process relatively simple.
2Reliability
If the UE connects to an LTE network for video telephony, then the data rate requirement is met, but call setup failure occurs due to inappropriate network switching
Solution Approach 1:
The patent implements preliminary identification of video telephony calls at the MME level before network switching occurs. The MME examines the Extended Service Request message, identifies video telephony indicators, and proactively prevents inappropriate 2G switching by controlling the CSFB execution, thereby avoiding call setup failures and reducing retry time.
3Adaptability or versatility
If the system performs measurement on both 2G and 3G cells, then the cell selection flexibility is increased, but the service quality degrades due to selection of 2G cells
Solution Approach 1:
The patent applies local quality by making the measurement configuration service-specific. For video telephony calls, the system configures measurement only on 3G cells (not 2G cells), while maintaining the ability to measure both 2G and 3G cells for other services. This is achieved through service-specific indication in the measurement configuration messages from eNB to UE.
Data Source
AI summary
A communication method and apparatus is provided for enhancing video telephony service quality by protecting against call setup failure or service quality degradation caused due to switching of the User Equipment (UE) to a network which does not fulfill the data rate required for video telephony in the video call setup process. The communication method of a terminal in a mobile communication system according to the present disclosure includes transmitting a video telephony call setup request message, receiving a switching command for Circuit Switched Fall Back (CSFB), and setting, if the switching command includes a target cell type set to the 2nd Generation (2G) cell and if a 3rd Generation (3G) cell to which the terminal can access exists, up the video telephony call by switching a connection to the 3G cell.