WLAN Location Determination Using OFDM Pilot Signals
Solution Overview
Problem
Existing wireless communication networks face challenges in accurately determining the location of mobile communication devices within mixed communication environments, which hinders the provision of location-based services without requiring specialized signals or significant network modifications.
Innovation Solution
The network determines the location of mobile communication devices by analyzing characteristics such as amplitude, phase, and frequency of existing pilot signals received over multiple signal pathways, using techniques like implicit beamforming and Angle of Arrival calculations, without introducing additional signals, and embeds location information in these signals to facilitate location-based services.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If existing pilot signals are analyzed for location determination, then location-based services can be provided without specialized signals, but accurate location determination in mixed communication environments becomes challenging
Solution Approach 1:
The patent uses existing pilot signals as intermediaries to convey location information. Instead of introducing specialized location determination signals, the system embeds location data within standard WLAN pilot signals that are already present in the mixed communication environment, allowing location determination without modifying the fundamental signal structure
Solution Approach 2:
The patent extracts location information by analyzing changes in signal parameters (amplitude, phase, frequency) of existing pilot signals as they propagate through different pathways. By monitoring parameter variations rather than signal presence, the system achieves location determination using standard signals designed for other purposes
2Quantity of substance
If location information is embedded in existing pilot signals, then no additional signals are needed, but the complexity of extracting location data from communication signals increases
Solution Approach 1:
The patent makes existing pilot signals multi-functional by enabling them to serve both their original communication purpose and location determination function simultaneously. The same pilot signals used for channel estimation and synchronization now also carry location information, eliminating the need for separate location signals
Solution Approach 2:
The system employs feedback mechanisms where the access point transmits pilot signals with embedded location information, the station receives and analyzes these signals to determine its location, and this location data is then used to provide location-based services. The continuous transmission of pilot signals provides ongoing location updates
Data Source
AI summary
A communication network of the present disclosure can determine one or more locations of communication devices within its geographic coverage area based upon one or more communication signals that are communicated within the communication network and/or between the communication network and another communication network. The one or more communication devices within the communication network can be implemented to utilize, for example, pilot signals encoded using orthogonal frequency-division multiplexing (OFDM) on multiple carrier frequencies to concurrently transmit the one or more communication signals over multiple signal pathways. The communication devices can determine one or more characteristics of these various communication signals that are received over the multiple signal pathways to assist in determining the one or more locations. Thereafter, the communication devices can determine one or more properties from the one or more characteristics to determine the one or more locations.