Pairwise Measurement Compensation for Indoor Positioning Accuracy
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Solution Overview
Problem
Conventional position location techniques in wireless communication systems face challenges in indoor and urban environments due to signal reflection, refraction, multipath, and signal attenuation, leading to reduced accuracy and longer 'time-to-fix' periods, especially when using signals from cellular base stations and satellite positioning systems.
Innovation Solution
The implementation of Pairwise Comparison and Compensation (PCC) methods, which involve collecting and comparing Round Trip Time (RTT) and Received Signal Strength Indicator (RSSI) measurements between nodes to detect and correct biases, thereby improving the accuracy of range-based position determination without requiring costly pre-deployment calibration or infrastructure changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional range-based position determination techniques are used in indoor environments, then position information can be obtained, but measurement accuracy deteriorates due to signal reflection, refraction, multipath, and attenuation
Solution Approach 1:
The patent implements a feedback mechanism where the first node receives measurements from the second node and uses these feedback measurements to compensate for biases in its own measurements. The pairwise comparison process creates a closed-loop system where measurement errors are detected and corrected through iterative refinement, improving position determination accuracy despite harmful RF environmental factors.
Solution Approach 2:
The patent changes the measurement parameters by collecting multiple types of measurements (RTT, RSSI, signal phase) and transforming them through pairwise comparisons to derive compensated range estimates. This parameter transformation approach converts raw measurements affected by multipath and attenuation into corrected measurements that are more reliable for position determination in indoor environments.
2Measurement precision
If pre-deployment fingerprinting and calibration are performed to remove time and amplitude biases, then measurement accuracy improves, but deployment time and complexity increase
Solution Approach 1:
The patent enables the network devices to self-calibrate through pairwise measurements without requiring external pre-deployment fingerprinting or calibration efforts. The devices automatically detect and compensate for their own time and amplitude biases by comparing measurements with neighboring nodes, eliminating the need for manual calibration processes and reducing deployment time while maintaining measurement accuracy.
Solution Approach 2:
The patent performs bias compensation continuously in the background through ongoing pairwise measurements between nodes. This preliminary and continuous calibration action occurs automatically as part of normal operation, preventing measurement errors before they affect position determination without requiring separate pre-deployment calibration activities.
3Measurement precision
If RTT and RSSI measurements are used for ranging, then position information can be derived, but measurement biases from network devices affect accuracy
Solution Approach 1:
The patent introduces pairwise comparisons as an intermediary process between raw RTT and RSSI measurements and final position determination. This intermediary step detects and compensates for time biases in RTT measurements and amplitude biases in RSSI measurements by comparing measurements from both ends of each wireless link, thereby eliminating device-generated measurement errors before they affect position accuracy.
Solution Approach 2:
The patent exploits the asymmetry in measurement biases between transmitting and receiving devices. By recognizing that each device introduces different time and amplitude biases, the pairwise comparison method captures these asymmetric errors and compensates for them by analyzing the difference between forward and reverse measurements, thereby improving range determination accuracy.
Data Source
AI summary
Approaches for enhancing range-based position determination using pairwise error detection and compensation are provided. One method for enhancing a position estimate of a first node may include performing measurements at the first node using a signal received from a second node, and receiving measurements from the second node. The received measurements may be performed at the second node using a signal provided by the first node. The method may further include determining pairwise comparisons of the performed measurements and the received measurements, and compensating the measurements performed at the first node, based on the pairwise comparisons, for estimating the position of the first node. Systems and apparatuses for performing the various position determination methods are further presented.