Pilot Signal Receiver AGC Control for Positioning Accuracy
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Solution Overview
Problem
Mobile stations face difficulties in accurately estimating position location due to signal interference and quantization errors, especially in environments where satellite signals are unavailable or weak, such as indoors or in tunnels, and existing technologies struggle to mitigate the 'hearability problem' and near-far effect in wireless communications systems.
Innovation Solution
The method involves partitioning sectors and signal dimensions to transmit nearly orthogonal enhanced pilot signals, reducing interference and using dynamic AGC adjustments to minimize quantization errors, while employing pseudo-random coloring and notch filters to improve signal detection and processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mobile stations use satellite positioning system signals for position estimation, then position location accuracy is improved, but signal reception reliability deteriorates in indoor or tunnel environments
Solution Approach 1:
The patent introduces terrestrial base station signals as an intermediary alternative when satellite signals are unavailable. The mobile station receives enhanced pilot signals from terrestrial base stations and uses these signals to estimate position location, thereby maintaining positioning capability in indoor or tunnel environments where satellite signals cannot penetrate.
2Measurement precision
If mobile stations receive enhanced pilot signals from multiple sectors, then position estimation capability is improved, but quantization error from digital automatic gain control increases
Solution Approach 1:
The patent applies preliminary action by storing the first DAGC value before receiving enhanced pilot signals and restoring it after reception. This prevents quantization error from occurring during the critical signal reception and processing phase, while still allowing the system to benefit from receiving multiple sector signals for position estimation.
Solution Approach 2:
The patent dynamically changes the DAGC parameter during signal processing by computing a second DAGC value during enhanced pilot signal reception. This parameter adjustment optimizes the digital automatic gain control to minimize quantization error while maintaining the ability to process multiple sector signals for improved position estimation.
3Adaptability or versatility
If mobile stations process signals from multiple base stations for position location, then versatility of positioning is improved, but signal interference increases
Solution Approach 1:
The patent partitions sectors and signal dimensions to transmit nearly orthogonal enhanced pilot signals. This segmentation creates distinct, non-interfering signal paths from multiple base stations, allowing the mobile station to process signals from multiple sources simultaneously without significant interference, thereby maintaining positioning versatility.
Data Source
AI summary
Briefly, in accordance with one embodiment, a method of adjusting for digital automatic gain control (DAGC) quantization error in a mobile station is as follows. A first DAGC value is stored before reception of one or more enhanced pilot signals. A second DAGC value is computed during reception of the one or more enhanced pilot signal. The first DAGC value is restored after reception of the one or more enhanced pilot signals is over. An advantage associated with this particular embodiment may include reduction in quantization error for digital automatic gain control.