MAC Protocol for Indoor Location in GPS-Denied Wireless Networks
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Solution Overview
Problem
Current wireless communication networks, especially ad-hoc multi-hopping networks, face challenges in accurately determining the location of mobile nodes within buildings due to the susceptibility of GPS techniques to errors and their inability to function in environments with limited satellite visibility, such as underground tunnels or urban canyons.
Innovation Solution
A MAC protocol system and method that controls communication between Mobile Terminals, Fixed References, and Main Control, optimizing message sequences to collect range measurements and compute precise location data, supporting location applications with a precision of better than two meters more than 90% of the time, and enabling voice exchange between team members in emergency situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS techniques are used for location determination, then location data can be obtained, but accuracy deteriorates in environments with limited satellite visibility such as underground tunnels or urban canyons
Solution Approach 1:
The patent introduces Fixed References as intermediary devices deployed within the building environment. These Fixed References act as mediators between Mobile Terminals and the location computation system, enabling accurate location determination in GPS-denied environments by providing local reference points for range measurements
Solution Approach 2:
The patent replaces the satellite-based GPS system with a terrestrial wireless communication-based location system. Instead of relying on electromagnetic signals from satellites, the system uses wireless signals transmitted between Mobile Terminals and Fixed References within the building to compute locations
2Measurement precision
If a large number of range measurements are collected to improve location accuracy, then measurement precision improves, but communication time and network overhead increase
Solution Approach 1:
The patent implements preliminary actions by having Mobile Terminals and Fixed References pre-synchronize their clocks and establish communication protocols before location measurements begin. This preliminary setup enables efficient measurement collection without repeated synchronization overhead during the actual measurement phase
Solution Approach 2:
The patent employs periodic measurement cycles where Mobile Terminals systematically measure ranges to multiple Fixed References in a structured sequence. This periodic approach ensures comprehensive data collection while maintaining efficient timing, collecting measurements from multiple references without requiring continuous communication
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves accurate and reliable location computation of mobile network members, supporting emergency operations by providing precise positioning and voice communication, even in challenging environments, with a high success rate and efficient data collection.
Implementation Method 1
based upon such measurements, permits a very precise computation of the location of terminals inside a building
Implementation Method 2
System and Method for Identifying the Floor Number Where a Firefighter in Need of Help is Located Using Received Signal Strength Indicator and Signal Propagation Time
Data Source
AI summary
A system and method for providing a MAC protocol that optimizes communication within a wireless network. Specifically, the system and method operates with Mobile Terminals, Fixed References and at least one Main Control, wherein a method defines the sequence of messages exchanged between each Mobile Terminals, Fixed Reference and the Main Control for assuring the data is optimally communicated within the network.