WCDMA Serving Cell Handover via Preliminary Configuration
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Solution Overview
Problem
In WCDMA systems, especially with HSDPA technology, serving cell handovers are delayed due to repeated configurations and signaling delays, leading to high drop call rates and poor user experience, particularly in areas with fast signal fading and high user mobility.
Innovation Solution
A method where a Radio Network Controller (RNC) sets up a radio link with a candidate cell, sends configuration information to User Equipment (UE), and uses an Iub interface signaling message to instruct the target base station to initiate a serving cell handover, avoiding reconfiguration messages and reducing handover delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the prior art uses reconfiguration messages for serving cell handover, then the handover procedure is complete and reliable, but the handover delay is long causing service suspension
Solution Approach 1:
The RNC performs preliminary configuration of the candidate cell during radio link setup before handover is needed. Configuration information including HS-SCCH channelized code, MAC-ehs parameters, and other HSDPA-related settings are prepared in advance and stored at both the RNC and target Node B, eliminating the need for reconfiguration during actual handover execution
Solution Approach 2:
The invention extracts and removes the reconfiguration messaging steps from the handover procedure. By separating the configuration phase (radio link setup) from the handover execution phase, the patent eliminates the time-consuming reconfiguration message exchange that traditionally occurred during handover, keeping only the essential handover command and confirmation messages
2Reliability
If the RNC sends reconfiguration signaling during handover preparation, then the candidate cell can be properly configured, but the signaling transmission time is long causing extra delay
Solution Approach 1:
Configuration of the candidate cell is performed in advance during radio link setup procedure. The RNC sends radio link setup messages to the target Node B with all necessary HSDPA configuration parameters, and the target Node B acknowledges receipt. This preliminary configuration ensures all settings are ready before handover execution, eliminating the need for time-consuming reconfiguration signaling during handover
Solution Approach 2:
The invention merges the configuration signaling with the radio link setup procedure. Instead of sending separate reconfiguration messages during handover, all configuration information is transmitted as part of the initial radio link establishment between the RNC and the target Node B, combining two functions into one efficient process
3Manufacturing precision
If the system waits for reconfiguration response messages during handover, then configuration accuracy is ensured, but the waiting time increases handover delay
Solution Approach 1:
The target Node B acknowledges receipt of configuration information during the radio link setup phase, confirming that all HSDPA parameters and settings are properly stored and ready for use. This preliminary acknowledgment eliminates the need for waiting for reconfiguration responses during actual handover execution, as configuration validity is already confirmed in advance
Data Source
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AI summary
The present invention provides a method, an apparatus and a system for informing a serving cell handover, which relate to radio communication technology, and can greatly reduce delay of the handover of the HS-DSCH serving cell, decrease the drop call rate, and enhance user's experience. The method for informing a serving cell handover includes: a radio network controller (RNC) sets up a radio link with a candidate cell, and sets configuration for the candidate cell during the process of setting up the radio link; the RNC sends configuration information of the candidate cell to user equipment (UE); and after acquiring an optimum cell, the RNC informs, through an Iub interface signaling message, a target base station of sending a serving cell handover instruction to the UE. The serving cell handover instruction instructs the UE to hand over to the optimum cell according to the configuration information. The present invention is suitable for occasions where the serving cell hands over in the radio network.