Indoor Positioning Gain Control for NLOS Accuracy
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Solution Overview
Problem
Existing indoor positioning techniques using cellular networks face accuracy issues under non-line-of-sight (NLOS) conditions due to blocked direct paths between communication nodes, leading to incorrect distance measurements and positioning errors.
Innovation Solution
A method involving a communication node that estimates time intervals for direct and reflection paths, adjusts reception gain based on these intervals, and transmits this information to a positioning device to enhance positioning accuracy without requiring additional infrastructure or devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If positioning is performed using received signals under NLOS conditions, then positioning operation can be performed, but positioning accuracy deteriorates due to blocked direct paths and reflected signals
Solution Approach 1:
The system performs preliminary identification of the first arrival path (FAP) and estimates its time interval before processing positioning signals. By预先 determining the FAP and its characteristics, the system can compensate for NLOS effects and improve positioning accuracy while maintaining operation availability
Solution Approach 2:
The system changes the parameter of reception gain by applying a gain control function that varies gain based on the estimated FAP time interval. This parameter change allows the system to enhance direct path signals while suppressing reflected signals, resolving the contradiction between operation availability and positioning accuracy under NLOS conditions
2Measurement precision
If reception gain is increased to capture weak direct path signals, then direct path detection improves, but reflected signals also increase causing measurement errors
Solution Approach 1:
The system preliminarily estimates the FAP time interval before signal reception. This preliminary action enables the system to apply time-selective gain control that enhances direct path signals while suppressing reflected signals that arrive later, resolving the contradiction between detection accuracy and signal interference
Solution Approach 2:
The system applies different reception gain values to different time intervals: a first gain for signals before the FAP time interval and a second (smaller) gain for signals after the FAP time interval. This local quality approach allows selective enhancement of direct path signals while suppressing reflected signals
3Measurement precision
If conventional positioning methods are used without gain control, then system complexity remains low, but positioning accuracy under NLOS conditions is poor
Solution Approach 1:
The system performs preliminary FAP identification and time interval estimation using standard signal processing techniques. This preliminary action provides the basis for subsequent gain control without requiring complex additional hardware or algorithms, achieving improved NLOS positioning accuracy with moderate complexity increase
Solution Approach 2:
The system implements a gain control function that adjusts reception gain based on the estimated FAP time interval. This parameter change approach achieves improved positioning accuracy through software-based control rather than hardware complexity, resolving the contradiction between accuracy and device complexity
Data Source
AI summary
An operation method of a first communication node may comprise: receiving a first signal from a second communication node of the communication system; estimating a first time interval corresponding to a first path detected as a FAP among one or more paths through which the first signal is received; defining a first gain control function based on the estimated first time interval; receiving a second signal transmitted from the second communication node by variably controlling a reception gain based on the first gain control function; estimating a second time interval corresponding to a DP between the first and second communication nodes, based on a result of receiving the second signal based on the first gain control function; and transmitting relative distance information on the second time interval to a first positioning device.