Dual-Antenna Bluetooth Signal Processing for Mobile Terminal Location
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Solution Overview
Problem
Existing Bluetooth communication modules in vehicles, equipped with a single antenna, face limitations in accurately determining the location of a mobile terminal using trilateration or triangulation based on received signal strength indicator (RSSI) in the 2.4 GHz band, leading to inefficient location determination performance.
Innovation Solution
A signal processing apparatus employing two antennas with a 90-degree phase difference to receive and process reception signals from a mobile terminal, utilizing a decision tree technique and hysteresis technique to compare RSSI values and determine the terminal's location among defined regions, thereby improving location determination accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single antenna is used for Bluetooth communication, then the device complexity is reduced, but the location determination precision deteriorates
Solution Approach 1:
The single antenna is segmented into multiple antennas (at least two antennas with different polarization directions). Each antenna receives signals with different characteristics, allowing the system to process multiple signal components to determine location, thereby improving precision while keeping each individual antenna simple.
Solution Approach 2:
The system transitions from single-dimension signal reception (one antenna) to multi-dimensional signal reception (multiple antennas with different polarization directions). This dimensional expansion allows the system to extract more information from the signal environment, improving location determination accuracy.
2Device complexity
If RSSI-based trilateration or triangulation is used with a single antenna, then the system simplicity is maintained, but the location determination reliability deteriorates
Solution Approach 1:
The signal processing is segmented into multiple independent RSSI measurement channels, each corresponding to a different antenna. By processing RSSI values from multiple antennas with different polarization directions, the system achieves more reliable location determination while maintaining relatively simple processing logic for each channel.
Solution Approach 2:
The system uses feedback from multiple antenna signals to cross-validate location estimates. By comparing and processing RSSI values from multiple antennas, the system can identify and correct erroneous measurements, improving overall reliability of location determination.
3Measurement precision
If multiple antennas with different polarization directions are used, then the location determination precision is improved, but the device complexity increases
Solution Approach 1:
Each antenna is designed with specific local quality characteristics (different polarization directions) that are optimized for receiving signals from specific directions or under specific conditions. This allows the system to leverage the unique strengths of each antenna without requiring complex omnidirectional capabilities from each individual antenna.
Solution Approach 2:
The system merges the signal processing results from multiple antennas with different polarization directions. By combining the information from these diverse antenna sources, the system achieves improved location precision while distributing the complexity across multiple simpler components rather than requiring one highly complex antenna.
Data Source
AI summary
A method of determining a location of a mobile terminal location is provided. The method includes respectively receiving, by two antennas, first and second reception signals from the mobile terminal, calculating, by a communication module, a reception strength value (hereinafter referred to as RSSI_1) of the first reception signal and a reception strength value (hereinafter referred to as RSSI_2) of the second reception signal, and determining, by a location determination module, a region where the mobile terminal is located, based on a result obtained by comparing one RSSI of the RSSI_1 and the RSSI_2 with a reference value set based on a decision tree technique and a result obtained by comparing the one RSSI with a detailed reference value set based on a hysteresis technique.