Location Processing Unit for Distributed Antenna Systems
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Solution Overview
Problem
In indoor environments, such as buildings, wireless communication systems face challenges in providing precise location services for client devices due to signal obstruction, which hinders services like emergency 911 and GPS, as traditional methods like triangulation are ineffective in determining device location within distributed antenna systems.
Innovation Solution
A location processing unit (LPU) is integrated into the distributed antenna system to receive and analyze uplink RF signals, determining signal strengths and identifying the antenna unit with the strongest signal to accurately locate client devices, utilizing techniques like RSSI calculation and FFT for precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional triangulation methods are used to determine device location, then location services can be provided, but the methods become ineffective in indoor environments with signal obstruction
Solution Approach 1:
The patent introduces an intermediary approach by using the distributed antenna system's own infrastructure (antenna units and signal processing unit) as mediators to determine location. Instead of relying on external GPS satellites that are blocked by buildings, the system uses the antenna units as intermediaries to receive and analyze signals from client devices, enabling location determination within the indoor environment where traditional GPS fails.
Solution Approach 2:
The patent replaces the mechanical/traditional triangulation approach with a signal processing-based system. The signal processing unit analyzes signal characteristics (such as signal strength, timing information) received from multiple antenna units to determine device location. This substitution of the location determination mechanism allows the system to function effectively in indoor environments where traditional geometric triangulation becomes unreliable due to signal obstruction and multipath effects.
2Area of stationary object
If distributed antenna units are deployed throughout a building to extend wireless coverage, then seamless wireless coverage is provided, but location determination becomes difficult due to the distributed arrangement
Solution Approach 1:
The patent implements feedback mechanisms where the signal processing unit continuously receives and analyzes signal information from multiple distributed antenna units. By processing feedback signals that include characteristics such as signal strength, timing, and signal quality from each antenna unit, the system can accurately determine the location of client devices even though the antenna units are distributed throughout the building. This feedback approach allows the system to leverage the distributed architecture for both coverage and location determination.
Solution Approach 2:
The patent adds another dimension to location determination by utilizing signal processing techniques that analyze multiple signal characteristics simultaneously. Instead of relying solely on geometric positioning, the system incorporates signal strength measurements, timing information, and signal quality metrics as additional dimensions of data. This multi-dimensional approach enables precise location determination while maintaining the distributed antenna architecture that provides seamless wireless coverage throughout the building.
3Reliability
If RF antenna coverage areas are made small to minimize shared bandwidth, then fewer users per area reduce interference, but location services become less accurate
Solution Approach 1:
The patent makes the distributed antenna system multi-functional by enabling it to perform both communication and location determination tasks. The same antenna units that provide wireless communication services also serve as measurement points for location determination. The signal processing unit utilizes the communication signals already being transmitted and received by the antenna units to extract location information, thereby achieving multi-functionality without requiring separate dedicated location antennas or systems.
Solution Approach 2:
The patent changes the parameters used for location determination by analyzing multiple signal characteristics such as signal strength (RSSI), timing information, and signal quality metrics. Instead of relying on a single parameter like geometric distance, the system uses a combination of these parameters to accurately determine device location. This parameter change approach allows the system to maintain small antenna coverage areas for reduced interference while achieving sufficient location accuracy through comprehensive signal analysis.
Data Source
AI summary
Distributed antenna systems provide location information for client devices communicating with remote antenna units. The location information can be used to determine the location of the client devices relative to the remote antenna unit(s) with which the client devices are communicating. A location processing unit (LPU) includes a control system configured to receive uplink radio frequency (RF) signals communicated by client devices and determines the signal strengths of the uplink RF signals. The control system also determines which antenna unit is receiving uplink RF signals from the device having the greatest signal strength.