Indoor Mobile Device Location via RSSI and BER Lookup
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Solution Overview
Problem
In-building location determination using GPS is challenging due to weak satellite signals, and indoor location tracking with RSSI is error-prone and battery-intensive, especially when multiple devices are involved in a piconet system.
Innovation Solution
Combining Received Signal Strength Indication (RSSI) and Bit Error Rate (BER) data to provide a unique signature for accurate location tracking, allowing a mobile device to function as a slave in the network and utilize a lookup table for precise positioning within a building.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RSSI approach is used for indoor location tracking, then location determination is possible, but location accuracy deteriorates due to signal reflection and ferrous materials
Solution Approach 1:
The patent combines multiple measurement parameters (RSSI, BER, and other signal characteristics) to create a composite location determination system. By merging these different types of data, the system compensates for the weaknesses of individual parameters and achieves more accurate and reliable location tracking in environments with signal reflections and ferrous materials.
Solution Approach 2:
The patent changes from relying solely on RSSI to using multiple parameters including BER (Bit Error Rate) and other signal characteristics. This parameter diversification allows the system to distinguish between signal strength variations caused by distance versus those caused by reflections or obstacles, thereby improving location accuracy.
2Area of stationary object
If multiple devices are used in a piconet system for location tracking, then location coverage is improved, but battery consumption increases due to duty cycle requirements
Solution Approach 1:
The patent implements periodic location updates rather than continuous tracking. Devices can enter low-power states between updates, significantly reducing battery consumption while maintaining adequate location coverage. The system determines when updates are necessary based on movement detection or time intervals.
Solution Approach 2:
The system allows devices to autonomously determine their location using pre-stored reference data and local measurements, reducing the need for constant communication with master devices. This self-service capability minimizes energy-consuming communications while maintaining location awareness.
3Ease of operation
If mobile device functions as master in piconet, then communication control is improved, but device compatibility deteriorates as other devices cannot communicate with master
Solution Approach 1:
The patent designs the location determination system to work with devices in any role (master or slave) within the piconet. By making the location measurement capability universal and role-independent, the system maintains both communication control benefits and broad device compatibility, allowing any device to participate in location tracking regardless of its piconet role.
4Measurement precision
If time-of-flight measurements are used for location determination, then location accuracy is improved, but technical complexity increases due to nanosecond timing requirements
Solution Approach 1:
The patent uses readily available, low-cost wireless communication hardware with built-in timing capabilities that can perform time-of-flight measurements without requiring specialized expensive equipment. The system leverages existing radio timing functions that operate at nanosecond precision through standard communication protocols, avoiding the need for complex dedicated timing hardware.
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
This approach reduces location error rates and conserves battery life by using a combination of RSSI and BER data to determine the position of a mobile device within a building, offering a more accurate and efficient indoor location tracking system.
Implementation Method 1
Time-of-flight based on the propagation time of electromagnetic (EM) waves in space
Data Source
AI summary
Briefly, in accordance with one or more embodiments, the location of a mobile device within a floor plan of a building or the like environment may be determined using a single transmission link between transceiver and the mobile device. A bit error rate value and a receiver signal strength indication value are measured for the present location of the mobile device in the floor plan. The coordinates where the mobile device is located may be determined by looking up the measured bit error rate value and the received signal strength indication value in a lookup table. Due to environmental factors of the floor plan, the combination of the bit error rate value and the received signal strength indication value corresponds to a unique coordinate location in the floor plan from which the location of the mobile device may be determined.