Terminal Location Estimation Using Base Station Unique Sequences
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Solution Overview
Problem
Existing methods for estimating the location of a terminal in a multi-cell communication environment, such as ToA-based methods and GPS receivers, are inefficient due to high power consumption and increased costs, and require accurate clock synchronization, which can lead to errors.
Innovation Solution
A location estimating method that involves receiving and processing unique sequences transmitted from adjacent base stations, extracting components corresponding to these stations, and estimating the terminal's location based on signal strengths or delays, without the need for a GPS receiver or synchronized clock, using unique sequences transmitted via a synchronization channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ToA-based location estimating method is applied, then location estimation accuracy is improved, but power consumption of terminal increases
Solution Approach 1:
The patent replaces the terminal's sequential measurement mechanism (mechanical operation) with a base station-based signal processing mechanism. The terminal simply receives and forwards the mixed signal, while the base station performs the complex extraction and measurement operations, thereby reducing terminal power consumption while maintaining location estimation accuracy.
Solution Approach 2:
The patent introduces an intermediary signal processing approach where the terminal receives mixed unique sequences from multiple base stations and forwards them without sequential measurement. The base station acts as an intermediary that performs the actual extraction and time difference calculation, eliminating the need for the terminal to sequentially measure each signal arrival time.
2Measurement precision
If GPS receiver is attached to terminal, then location estimation accuracy is improved, but overall cost of terminal increases
Solution Approach 1:
The patent creates a virtual GPS-like location estimation system using existing base station infrastructure and unique sequences. Instead of requiring physical GPS receivers in terminals, the system copies the functionality of GPS by having base stations transmit unique sequences that enable location estimation through signal processing at the base station side.
Solution Approach 2:
The patent makes the base station infrastructure multi-functional by having it not only provide communication services but also perform location estimation functions. The unique sequences transmitted by base stations serve dual purposes: communication synchronization and location estimation, eliminating the need for separate GPS hardware in terminals.
3Measurement precision
If ToA-based location estimating method is applied, then location estimation accuracy is improved, but clock synchronization requirement increases system complexity
Solution Approach 1:
The patent performs preliminary actions by having base stations transmit unique sequences with known timing relationships before location estimation is needed. The base station stores and transmits these pre-synchronized sequences, so when location estimation is performed, the timing information is already embedded in the transmitted signals, eliminating the need for real-time clock synchronization between terminal and base station.
Solution Approach 2:
The patent replaces the mechanical clock synchronization system with a signal-based timing reference system. Instead of requiring synchronized clocks between terminal and base station, the system uses pre-transmitted unique sequences with known timing characteristics as references, allowing the base station to calculate time differences without requiring the terminal to have a synchronized clock.
Data Source
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AI summary
A terminal receives a unique sequence from each of at least two base stations, and transmits a mixture of quantized unique sequences to a serving base station. The serving base station extracts components respectively corresponding to base stations from the mixture of the quantized unique sequences, and estimates a location of a terminal based on the extracted components. The serving base station may calculate a received signal strength or a delay for each of the unique sequences received by the terminal, based on the extracted components, and estimate the location of the terminal based on the received signal strength or the delay. In addition, the terminal may estimate its own location by performing an algorithm used by the serving base station.