Wireless Tag Area Differentiation via Short-Range Transmitters
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Solution Overview
Problem
Existing wireless location systems face challenges in accurately differentiating between areas without expensive infrastructure, particularly in outdoor and open environments, where methods like signal strength measurement, RFID, infrared, and ultrasonic signals are unreliable or require extensive coverage.
Innovation Solution
The method involves installing short-range transmitters at entrance/exit points to broadcast identifying area information, which wireless tags receive and transmit, allowing location receivers to differentiate between areas without extensive infrastructure, using low-frequency RFID transmitters or other short-range devices to program tags with area IDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If signal strength measurement (RSSI) is used for area differentiation, then the method is simple to implement, but the reliability and accuracy are poor due to environmental conditions and multi-path propagation
Solution Approach 1:
The patent introduces area identification transmitters as intermediary devices that broadcast unique area identifiers. These transmitters act as mediators between the location system and the environment, providing reliable area differentiation signals that are not affected by environmental conditions, multi-path propagation, or signal strength variations that plague RSSI-based methods.
Solution Approach 2:
The patent replaces the physical signal strength measurement approach (which relies on RF signal propagation through the environment) with a information-based identification system. Instead of measuring how strong a signal is (physical quantity), the system uses transmitted area identifier messages (information), which are not subject to the same environmental degradation.
2Reliability
If RFID methods are used for area differentiation, then the reliability is good in closed or open areas, but the infrastructure cost is high due to heavy deployment requirements
Solution Approach 1:
The patent segments the area differentiation function into localized transmitters positioned at specific points (entrances, exits, or key locations within areas) rather than requiring continuous coverage infrastructure. Each transmitter independently broadcasts its area identifier, and the tracking device accumulates these identifiers to determine its location, eliminating the need for dense infrastructure deployment.
Solution Approach 2:
The patent uses partial action by placing transmitters only at critical locations (entrances, exits, or representative points within areas) rather than providing continuous coverage throughout all spaces. This partial deployment is sufficient because the tracking device carries the area identification information with it as it moves, eliminating the need for excessive infrastructure.
3Measurement precision
If infrared or ultrasonic signals are used for area differentiation, then the performance is good in indoor closed areas, but the reliability is very poor in outdoor and open areas
Solution Approach 1:
The patent uses radio frequency transmitters that can operate universally in both indoor and outdoor environments. Unlike infrared or ultrasonic systems that are environment-specific, the RF-based area identification transmitters provide consistent performance across diverse environments, making the system adaptable to various settings from enclosed rooms to open outdoor areas.
4Measurement precision
If tracking algorithms are used to improve area differentiation, then the accuracy is improved, but the system requires frequent location updates which increases complexity and reduces reliability for slow update rates
Solution Approach 1:
The patent performs preliminary action by having area identification transmitters continuously broadcast their area identifiers before the tracking device needs to determine its location. The tracking device receives and stores these identifiers as it moves through areas, so when location determination is needed, the information is already available without requiring complex real-time tracking algorithms or frequent updates.
Data Source
AI summary
A system and method for tracking and locating wireless tags by a wireless location system in limited and well defined areas that provides for differentiation between the well defined areas comprises transmitting identifying area information by short range transmitters, at least one short range transmitter positioned in the proximity of an entry and exit point of each well defined area. The wireless tags receive the identifying area information when in coverage range of one of the short range transmitters. The wireless tags will transmit the identifying information in the tag message. The transmission will include the last identifying information received and accepted by the wireless tag. A plurality of location receivers and/or access points are installed in or in the proximity of the well defined areas for locating the wireless tags.