WCDMA to CDMA Handover via Pilot Signal Acquisition
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Solution Overview
Problem
Conventional handover methods from Wideband CDMA (WCDMA) to Code Division Multiple Access (CDMA) networks disconnect calls due to the need to turn off WCDMA modules and turn on CDMA modules, causing interruptions when a mobile communication terminal moves from a WCDMA area to a CDMA area.
Innovation Solution
A method that determines the necessity of handover from WCDMA to CDMA, activates the CDMA module, acquires a pilot signal, and transfers necessary information to enable seamless handover by setting parameters for CDMA mode, allowing continuous communication without disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the WCDMA module is turned off and the CDMA module is turned on during handover, then the terminal can switch between networks, but the call is disconnected
Solution Approach 1:
The terminal performs preliminary actions by acquiring synchronization signals and pilot signals from the target CDMA base station before the actual handover occurs. This preparation includes obtaining system parameters and establishing signal acquisition in advance, so that when the network switch happens, the terminal is already ready to maintain the call connection.
Solution Approach 2:
The invention uses synchronization signals and pilot signals as intermediaries to facilitate the handover process. These signals serve as a bridge between the WCDMA and CDMA networks, allowing the terminal to acquire necessary system information and maintain call continuity during the transition without direct module switching disruption.
2Reliability
If the terminal acquires synchronization signal and pilot signal from CDMA base station, then handover can be performed, but the process becomes complex
Solution Approach 1:
The handover process is segmented into distinct phases: first acquiring the synchronization signal to obtain basic system parameters, then acquiring the pilot signal for channel estimation and signal quality assessment. This segmentation allows each signal type to be processed independently with specific algorithms, reducing overall complexity while improving reliability.
Solution Approach 2:
The terminal performs preliminary signal acquisition and parameter extraction before the actual handover execution. By obtaining synchronization information and pilot signals in advance, the terminal prepares all necessary data structures and parameters, simplifying the subsequent handover process and reducing computational complexity during the critical switching moment.
Data Source
AI summary
A method of performing a handover from a Wideband Code Division Multiple Access (WCDMA) system to a Code Division Multiple Access (CDMA) system in a multi-mode terminal having a WCDMA module and a CDMA module is disclosed. The method includes determining whether a handover to the CDMA system is necessary during a call through a WCDMA system; acquiring a pilot signal from the CDMA system by activating the CDMA module if it is determined that the handover to the CDMA system is necessary; receiving a sync signal if the pilot signal from the CDMA system is acquired; transmitting information for handover to the WCDMA system through the WCDMA module; allowing the CDMA module to enter a CDMA traffic state using handover information if the handover information is received from the WCDMA system through WCDMA module; and releasing a traffic state of WCDMA module.