Base Station Synchronization Using Interfering Downlink Signals
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Solution Overview
Problem
Current broadband wireless access systems face challenges in synchronizing base stations, particularly in indoor environments where GPS receivers may not function effectively, leading to interference and increased costs due to the need for GPS-equipped base stations.
Innovation Solution
The method involves using downlink transmissions from interfering base stations to provide synchronization for a base station of interest, establishing a synchronization hierarchy with multiple master/slave levels, and employing a discovery phase to select a master base station for initial and periodic synchronization, eliminating the need for GPS receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS receivers are installed in each base station to provide synchronization, then synchronization accuracy is improved, but system implementation cost increases significantly
Solution Approach 1:
The patent introduces a base station controller as an intermediary that centralizes the synchronization function. Instead of each base station having its own GPS receiver, the controller receives synchronization signals from GPS and distributes timing information to all base stations, eliminating the need for multiple GPS receivers while maintaining synchronization accuracy
Solution Approach 2:
The base station controller performs multiple functions including synchronization management, interference coordination, and resource allocation. By making the controller a multi-functional component, the system avoids duplicating expensive GPS equipment across multiple base stations
2Reliability
If GPS receivers are installed in each base station to provide synchronization, then synchronization reliability is improved, but device complexity increases
Solution Approach 1:
The patent extracts the GPS receiver function from individual base stations and relocates it to a centralized base station controller. This separation removes the complexity of GPS equipment from base stations while maintaining synchronization reliability through the centralized controller
Solution Approach 2:
The base station controller acts as an intermediary that manages synchronization reliability centrally. It receives GPS signals once and distributes synchronized timing information to all base stations, ensuring reliable synchronization without adding GPS equipment to each base station
3Object-affected harmful factors
If base stations are synchronized using traditional methods, then interference between cells is reduced, but implementation cost increases due to GPS requirements
Solution Approach 1:
The patent converts the harmful effect of inter-cell interference into a useful synchronization mechanism. By having base stations detect and measure interference from neighboring cells, the system uses this interference information to establish timing relationships and achieve synchronization without requiring expensive GPS equipment
Solution Approach 2:
Base stations perform self-synchronization by detecting interference signals from neighboring cells and using these signals to adjust their timing. This self-service approach eliminates the need for external GPS equipment while reducing inter-cell interference through coordinated timing
Data Source
AI summary
Synchronization between base stations in a broadband wireless access system is achieved using interfering base stations. Interfering base stations are first identified for a base station of interest (BSOI). One of the interfering base stations is then selected to be a master base station for the BSOI. The BSOI may then establish and maintain synchronization with the master base station.