Architectures for Ultra-Low-Power Multi-Channel Resonator-Based Wireless Transceivers

Abstract

Wireless capsule endoscope (WCE) has become one of the most popular inspection de-vices which provides visual investigation of entire gastrointestinal (GI) tract. Whilethe other traditional (wired) endoscopic devices are usually used for colon and stom-ach inspection. Locating abnormalities such as tumors, polyps and bleedings with wire-connected endoscope in GI tract is simple as long as we could measure the length ofthe wires inside human body. When WCE is applied, however, this becomes a criticalchallenge of examination since there is no wires connected to WCE while physiciansneed to find the exact locations of WCE to identify the position of abnormalities. To lo-cate the WCE accurately, methods have come up in last decade including time of arrival(TOA) based methods, received signal strength (RSS) based methods, phase difference ofarrival (PDOA) based methods, electromagnetic methods and video-based tracking meth-ods, etc.. In this thesis, the accuracy of TOA, PDOA and video based localization methodsare analyzed. (1) We propose a novel video-based tracking technique based on maximummutual information, which provides a more accurate measurement of the displacementand rotation of the WCE inside the large intestine. (2) We derive the Cramer-Rao lowerbound (CRLB) of TOA ranging using a single tone inside homogeneous tissues to ex-amine the accuracy of three TOA ranging techniques. Then we compare the accuracyof these ranging techniques in non-homogeneous tissues with that in homogeneous tis-sues. (3) We also apply PDOA based ranging technique exploiting phase difference oftwo signals. Since the phase difference is taken into consideration, the ranging ambiguityof single tone is eliminated. We evaluate the accuracy of the proposed PDOA rangingtechnique and compare with that of TOA techniques.