Comparison of TOA and RSS based techniques for RF localization inside human tissue.

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Radio Frequency Engineering

Background:

• Accurate radio frequency (RF) localization within the human body is crucial for emerging medical applications like Capsule Endoscopy.
• The precision of RF localization is contingent upon the chosen technology, with Received Signal Strength (RSS) and Time-of-Arrival (TOA) being the most prevalent.
• Simulating radio wave propagation within human tissue presents significant analytical challenges and demands substantial computational resources.

Purpose of the Study:

• To conduct a comparative analysis of the localization accuracy between TOA and RSS techniques within human tissue.
• To evaluate the performance of TOA and RSS localization against the theoretical bounds provided by the Cramér-Rao Lower Bound (CRLB).

Main Methods:

• Utilized a proprietary, high-speed Finite Difference Time Domain (FDTD) algorithm for simulating radio wave transmissions inside the human body, achieving speeds approximately 60 times faster than commercial solvers.
• Extracted Time-of-Arrival (TOA) and Received Signal Strength (RSS) data from simulated waveform transmissions.
• Quantitatively compared the localization accuracy of TOA and RSS methods.

Main Results:

• Demonstrated that Time-of-Arrival (TOA) based localization exhibits higher accuracy within human tissue compared to Received Signal Strength (RSS) based localization.
• The performance of both TOA and RSS methods was benchmarked against the Cramér-Rao Lower Bound (CRLB) to establish theoretical performance limits.

Conclusions:

• Time-of-Arrival (TOA) is a more accurate method for radio frequency (RF) localization inside human tissue than Received Signal Strength (RSS).
• The developed FDTD simulation technique provides a computationally efficient tool for analyzing RF wave propagation in biological tissues.