Wireless Signal Propagation Delay Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Propagation delays in wireless signals, caused by mismatches, stray capacitances, antenna cable lengths, tower height, and signal scattering, significantly affect the accuracy of location estimates in mobile networks, particularly in distributed antenna systems and low-power wireless cells, leading to substantial errors in timing advance and round trip time calculations.
Innovation Solution
The system compensates for propagation delays by determining the effective total timing delay through statistical analysis of accurate location estimates from reference positions and time-of-flight measurements, using assisted GPS or other GNSS systems, and calibrating propagation delays iteratively to improve the accuracy of time-of-flight location estimates and enhance radio network performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If propagation delay compensation is not implemented, then the system architecture remains simple and timing measurements are straightforward, but location estimation accuracy deteriorates significantly with errors of several hundred meters
Solution Approach 1:
The patent applies preliminary action by pre-calibrating propagation delay values for different base station configurations (antenna cable lengths, tower heights) before actual location measurements. These pre-determined delay values are stored and automatically applied during location estimation, eliminating the need for complex real-time delay calculation and measurement while significantly improving location accuracy
Solution Approach 2:
The patent introduces propagation delay compensation values as an intermediary element between the raw timing measurements and the final location calculation. These compensation values, derived from known base station parameters and calibration data, mediate the relationship between signal travel time and actual distance, correcting systematic errors without requiring complex real-time measurements
2Measurement precision
If propagation delay compensation is implemented, then location estimation accuracy improves significantly, but the calibration process becomes more complex and time-consuming
Solution Approach 1:
The calibration process is performed preliminarily during system setup or maintenance periods, not during normal operation. Base station parameters (antenna cable lengths, tower heights) are measured and stored in advance, and propagation delay values are pre-calculated and stored in lookup tables, eliminating the need for complex real-time calibration
Solution Approach 2:
The patent changes the approach from dynamic measurement to static parameter storage. Instead of measuring propagation delays in real-time, the system uses predetermined parameters (cable lengths, tower heights) to determine delay values, which are then stored and reused. This transforms a complex measurement process into a simple parameter lookup operation
3Productivity
If propagation delays are assumed negligible, then the system operation remains simple and fast, but location services utility is substantially diminished
Solution Approach 1:
Propagation delay compensation values serve as an intermediary that reconciles the conflict between simple operation and accurate location services. These pre-calculated values allow the system to maintain simple, fast operation while correcting timing delays, thereby preserving location service utility without sacrificing operational efficiency
Solution Approach 2:
By pre-determining propagation delay values during system setup, the patent enables fast location measurements without real-time delay correction. The preliminary calibration allows subsequent location measurements to be both rapid and accurate, maintaining productivity while compensating for timing losses
Data Source
AI summary
Propagation delay offsets of wireless signals are compensated. Compensation is accomplished through determination of an effective wireless signal propagation delay that accounts for signal path delay and propagation delay over the air. Such determination is based at least in part on statistical analysis of accurate location estimates of reference positions throughout a coverage sector or cell, and location estimates of the reference positions generated through time-of-flight (TOF) measurements of wireless signals. Determination of propagation or signal path delay offset also is attained iteratively based at least in part on reference location estimates and TOF location estimates. High-accuracy location estimates such as those obtained through global navigation satellite systems are employed as reference location estimates. Position of probes or wireless beacons, deployed throughout a sector or cell, also are employed as reference locations. Compensation of propagation delay offset improves accuracy of conventional TOF location estimates and radio network performance.