Base Station Synchronization via Timing Reference Signals
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Solution Overview
Problem
Current methods for synchronizing base stations in wireless communication systems, such as GNSS and IEEE 1588 Precision Time Protocol, fail to achieve the stringent 100 nanosecond accuracy required for OTDOA and UTDOA position location techniques due to limitations like satellite unavailability, complex retrofitting, packet delay variations, and network path asymmetry, resulting in synchronization accuracy that is several orders of magnitude too large.
Innovation Solution
A method and apparatus for base station synchronization that involves each base station transmitting and receiving timing reference signals to determine timing offsets, combining redundant measurements to achieve optimal synchronization, and accounting for propagation delays to ensure precise timing adjustments, thereby meeting the stringent timing requirements for OTDOA and UTDOA techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS or IEEE 1588 methods are used for base station synchronization, then base stations can achieve timing reference, but the synchronization accuracy cannot meet the 100 nanosecond requirement due to satellite unavailability, complex retrofitting, packet delay variations, and network path asymmetry
Solution Approach 1:
The patent introduces a positioning reference signal as an intermediary medium for timing reference transmission between base stations. Instead of relying on external systems like GNSS or complex network protocols, base stations exchange timing information directly through standardized downlink reference signals that are already part of the LTE infrastructure, thereby achieving 100 nanosecond synchronization accuracy without adding system complexity
Solution Approach 2:
The patent enables base stations to self-synchronize by having them transmit and receive positioning reference signals autonomously. Each base station determines timing offsets based on signals received from neighboring base stations and adjusts its own transmission timing accordingly, eliminating the need for external synchronization infrastructure or complex retrofitting
2Adaptability or versatility
If base stations transmit positioning reference signals with different configurations, then each base station can optimize its signal transmission, but timing offsets between base stations increase, reducing OTDOA measurement accuracy
Solution Approach 1:
The patent changes the configuration parameters of positioning reference signals to achieve both adaptability and timing accuracy. Specifically, it configures base stations to transmit positioning reference signals in the same subframes with consistent timing relationships, while allowing individual base stations to adjust signal-specific parameters like resource element positions and sequence initialization based on their cell-specific parameters. This ensures that timing offsets remain predictable and measurable while maintaining signal optimization for each base station
Data Source
AI summary
A first base station synchronizes with one or more second base stations by transmitting, from the first base station, a first timing reference signal and receiving, at the first base station, one or more second timing reference signals transmitted by the one or more second base stations. The method also includes determining one or more first timing offsets between the first base station and the one or more second base stations based on the one or more second timing reference signals. The method further includes adjusting a timing associated with the first base station based on the one or more first timing offsets and one or more second timing offsets determined based on the first timing reference signal.