Battery-less Tag Location via Controlled Energy Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for locating wireless tags, particularly those using Bluetooth Low Energy (BLE) protocol, face challenges due to noisy Received Signal Strength Indication (RSSI) caused by interference and channel loss, making it difficult to determine the location of battery-less tags accurately.
Innovation Solution
A method involving tag readers transmitting signals with controlled energy levels, monitoring the transmission rates of battery-less wireless tags, and correlating these rates with changes in energizing signal power to determine the tag's location, accounting for channel loss and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RSSI-based triangulation is used to locate wireless tags, then location determination is possible, but measurement precision deteriorates due to noisy RSSI signals caused by channel loss, interference, and multiple readers creating zone bleeding
Solution Approach 1:
The patent changes the measurement parameter from RSSI (which is noisy and unreliable) to packet transmission rate (which is more reliable). By monitoring how many packets a tag transmits in response to reader signals, the system achieves more accurate location determination without being affected by channel loss and interference that plague RSSI measurements
Solution Approach 2:
The patent introduces an intermediary measurement approach - instead of directly measuring the noisy RSSI signal, it uses packet transmission rate as an intermediary indicator that correlates with distance but is less susceptible to noise. The reader sends signals and counts how many packets the tag responds with, using this count rate as a more reliable proxy for location
2Measurement precision
If reader deployment density is increased to improve location accuracy, then measurement precision improves, but use of energy increases due to more readers transmitting energizing signals
Solution Approach 1:
The patent uses partial action by having readers transmit energizing signals only when needed for location measurements, rather than continuously. The system can determine location using data from one or a few readers without requiring all readers to be actively transmitting, thus reducing overall energy consumption while maintaining measurement precision
Solution Approach 2:
The tags are battery-less and harvest energy from reader signals to power their own packet transmissions. This self-service approach means the tags do not require separate power sources, and the energy expenditure is concentrated in the readers only when location measurements are being performed, rather than continuous operation
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 allows for accurate determination of a battery-less wireless tag's location by analyzing transmission rates in response to varying energizing signal power, effectively mitigating the issues of noisy RSSI and channel loss, even in environments with high interference.
Implementation Method 1
transmitting, by the tag reader, at least one wireless signal having a controlled known energy
Implementation Method 2
for battery-less tags that have to harvest energy from an energizing signal transmitted by a reader
Data Source
AI summary
A method for determining a location of a battery-less wireless tag by a tag reader being at a fixed-location. The method comprises: transmitting, by the tag reader, at least one wireless signal having a controlled known energy; receiving at the tag reader at least one packet transmitted by the tag within a time window; and responsive to a determination at the tag reader of at least one transmission rate of packets by the wireless tag based on the at least one received packet, determining information regarding the location of the tag.