RNC Common Channel Timing Control for WCDMA Signal Merging
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Solution Overview
Problem
Current 3G mobile communication systems, particularly WCDMA, face challenges in controlling time delays of signals transmitted from adjacent cells via a common channel, which affects signal merging and reception quality, leading to reduced system capacity due to interference and inability to meet the required time delay within a small range.
Innovation Solution
A method involving the RNC obtaining and configuring transmission delays and time differences between base stations, informing UE of frame and chip offsets, and receiving common channel configuration parameters to synchronize and control data transmission start times, ensuring time delays are within a relative small range, allowing for effective signal merging and improved reception quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a common channel is adopted for MBMS service to share radio resources among multiple UEs, then radio resource utilization is improved, but time delay control of signals from adjacent cells deteriorates
Solution Approach 1:
The RNC performs preliminary actions by obtaining transmission delays and time differences between the RNC and respective base stations before configuring cells and common channels. This advance preparation enables the RNC to calculate and set appropriate frame offsets and chip offsets, ensuring that time delay requirements are met before actual data transmission begins.
Solution Approach 2:
The invention changes key timing parameters including frame offset, chip offset, transmission delay, and time difference to control the time delay of signals from adjacent cells. By adjusting these parameters, the RNC ensures that the absolute difference in transmission delays between any two cells is within the required range (±148 chips), thereby resolving the time delay control issue while maintaining common channel resource sharing.
2Reliability
If signals from multiple cells are merged to improve reception quality, then signal quality is improved, but time delay synchronization becomes more difficult to control
Solution Approach 1:
The RNC obtains transmission delays and time differences from base stations, uses this feedback information to calculate appropriate frame offsets and chip offsets, and then configures cells and common channels accordingly. This feedback mechanism ensures that signal merging can be performed while maintaining time delay synchronization within required limits.
Solution Approach 2:
The RNC acts as an intermediary between base stations and UEs, centralizing the time delay control function. By obtaining transmission delay information from base stations and calculating appropriate offsets, the RNC mediates the timing synchronization required for successful signal merging at the UE, simplifying the overall synchronization complexity.
3Manufacturing precision
If frame offset and chip offset are configured to control transmission timing, then time delay control is improved, but system complexity increases
Solution Approach 1:
The base stations self-report their transmission delays to the RNC, and the RNC automatically calculates and configures the appropriate frame offsets and chip offsets for each cell. This self-service approach reduces manual configuration complexity while maintaining precise time delay control, as the system automatically adapts to the actual transmission characteristics of each base station.
Data Source
AI summary
A method for controlling data transmission comprising following steps of: obtaining transmission delays and time differences between a RNC and respective base stations by the RNC; configuring cells and a common channel for data transmitting by the RNC; controlling a start time of data transmission of each cells by the RNC; informing a UE of a frame offset and a chip offset of the common channel through an interface Uu by the RNC; and receiving configuration parameters of the common channel transmitted from the RNC by the UE. In the present invention, merging of signals transmitted from different cells via the common channel has been achieved so that the quality of signals received by the UE has been improved and the throughput of the system has been enlarged.