Air-Interface Synchronization for Base Station Time Alignment
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Solution Overview
Problem
The high construction and maintenance costs associated with GPS-based time synchronization in wireless networks, particularly in densely deployed LTE systems, lead to increased interference and reduced throughput for users on cell borders.
Innovation Solution
Implementing air-interface-based time synchronization using a central controller that acquires and adjusts time differences between base stations through active random access of user equipment, eliminating the need for expensive synchronization devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS-based time synchronization is used between base stations, then time synchronization accuracy is improved, but construction cost and maintenance cost increase
Solution Approach 1:
The patent uses air interface signaling to copy the time synchronization function that would otherwise require GPS hardware. The central controller creates virtual time references through message exchanges on the existing air interface, eliminating the need for physical GPS receivers at each base station while maintaining synchronization accuracy
Solution Approach 2:
The patent replaces the mechanical/GPS-based synchronization system with an electromagnetic communication-based system. Instead of using GPS satellites and ground-based antenna hardware, the solution uses wireless signaling through the air interface to transmit time reference information between base stations and the central controller
2Measurement precision
If GPS-based time synchronization is used between base stations, then time synchronization accuracy is improved, but maintenance cost increases
Solution Approach 1:
The system enables base stations to self-synchronize using the air interface infrastructure that already exists for normal communication. The central controller automatically manages time reference distribution through standard signaling procedures, eliminating the need for specialized GPS maintenance personnel and equipment
Solution Approach 2:
The air interface signaling system serves multiple functions simultaneously: it provides both normal communication services and time synchronization functions. This multi-functionality eliminates the need for separate GPS hardware maintenance, as the same communication infrastructure handles both data transmission and timing reference distribution
3Productivity
If sites are deployed more densely to increase network capacity, then network capacity is improved, but interference between cells increases
Solution Approach 1:
The patent implements dynamic time domain resource allocation where ABS patterns can be adjusted and reconfigured based on current network conditions and interference levels. This dynamic approach allows the system to adapt to changing traffic patterns and interference scenarios, optimizing edge user throughput while maintaining overall network capacity
Solution Approach 2:
The system uses periodic ABS (Almost Blank Subframes) where interfering cells periodically transmit only reference signals during designated subframes. This periodic structure creates predictable interference patterns that can be coordinated across multiple cells, allowing edge users to experience reduced interference during these scheduled intervals while maintaining high capacity during non-ABS subframes
Data Source
AI summary
The present disclosure discloses an air-interface-based synchronization method, a base station and its control apparatus, and a wireless communications system. By taking advantage of active random access of user equipment, a time difference between base stations is acquired by detecting a random access preamble, and a time adjustment value of a non-reference base station is acquired according to the acquired time difference and reference time of a reference base station; and the non-reference base station performs time adjustment according to the acquired time adjustment value, to complete time synchronization with the reference base station. The present disclosure can easily and effectively implement air-interface-based synchronization between base stations by using an existing wireless network, thereby achieving a technical effect in a convenient and economic manner.