Base Station Frame Synchronization via Downlink Timing
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Solution Overview
Problem
Existing communication networks face challenges in synchronizing base station frame transmissions without relying on external timing references like GPS, which are costly and unreliable in dense urban areas or indoor environments.
Innovation Solution
The method involves determining the start time of downlink frame reception and radio frequency propagation delay at one base station to estimate a reference downlink frame transmission time, allowing synchronization of frame transmissions among base stations without external timing sources, using internal clock systems and pre-assigned time slots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS receivers are used for base station synchronization, then timing accuracy is improved, but cost and reliability in poor coverage areas worsen
Solution Approach 1:
The patent introduces a downlink frame signal from another base station as an intermediary reference source. Instead of directly using GPS, each base station uses the transmitted downlink frame from a neighboring base station to determine its transmission timing, creating a distributed synchronization network that works independently of GPS coverage
Solution Approach 2:
The system enables base stations to synchronize themselves using signals already present in the network (downlink frames from other base stations). Each base station determines its own transmission start time based on received downlink frames, eliminating the need for external GPS infrastructure and making the system self-sufficient
2Reliability
If GPS receivers are deployed at each base station, then synchronization capability is improved, but production and installation cost worsens
Solution Approach 1:
The system eliminates the need for expensive GPS receivers by enabling base stations to use existing downlink frame signals from other base stations for synchronization. This self-service approach uses already-available network signals rather than requiring additional expensive hardware at each site
Solution Approach 2:
Each base station copies the timing reference from downlink frames transmitted by other base stations. Instead of each station independently acquiring GPS signals, they all use the same synchronization mechanism based on replicated downlink frame structures across the network
3Device complexity
If base stations transmit frames simultaneously without synchronization, then device complexity is reduced, but co-channel interference increases
Solution Approach 1:
The system uses feedback from received downlink frames to adjust transmission timing. Each base station measures the arrival time of downlink frames from other stations and uses this feedback information to calculate and adjust its own transmission start time, creating a closed-loop synchronization system that minimizes interference
Solution Approach 2:
The patent replaces complex hardware-based synchronization mechanisms with a signal-processing approach. Instead of using precise mechanical timing devices or external reference sources, the system uses software-based calculation of transmission times based on received signal characteristics and propagation delay measurements
Data Source
AI summary
A method and apparatus for frame synchronization in a communication network is provided. The communication network includes a plurality of base stations. The method includes determining the start time of reception of a downlink frame received from each of at least a second base station. The method also includes determining the radio frequency propagation delay associated with the downlink frame received from the each of at least a second base station. Further, the method includes determining the reference downlink frame transmission time at the first base station, based on the reception start time of the downlink frame and the radio frequency propagation delay associated with one of the at least a second base station.