Energy efficient medium access control protocol for in-vivo multiple capsule networks
Date of Issue2012
School of Mechanical and Aerospace Engineering
Wireless capsule endoscopy is a type of medical device for diagnosing diseases inside small intestine giving little discomfort to the patients. It is envisaged that several capsule devices with different functionalities work together to perform some monitoring/therapeutic work. The capsules and the outside coordinator form a wireless network. As the capsule devices are powered by batteries that are difficult to replace, energy efficient MAC protocol plays an important role. This thesis focuses on proposing a novel energy efficient Medium Access Control (MAC) protocol for multiple capsule networks. The thesis reviews the engineering aspects of wireless capsule endoscopy and the current technologies, including in-vivo wireless communication, wireless power supply, active locomotion and localization. Later, a comprehensive survey of MAC protocols for wireless sensor networks and body sensor networks is conducted. Multi-hop communication through the human body is simulated for different circuitry power. The result shows that it can save energy compared with single hop wireless communication when the circuitry power is lowered to 100 µW. This was already achieved in the lab. Based on this result, a novel TDMA based MAC protocol is proposed for multiple capsule networks. It follows an uplink, downlink asymmetric topology giving lower power consumption. The TDMA frame is proposed in detail. Changeable frame format and adaptive power control further reduce the energy consumption. Simulation result shows that the proposed MAC protocol consumes less energy than 802.15.6 draft when circuitry power is 100 µW based on randomly generated mobility pattern. Hardware implementation of the proposed TDMA MAC protocol has been conducted.
DRNTU::Engineering::Electrical and electronic engineering::Wireless communication systems