As one of the BAN applications, wireless Capsule Endoscopy offers a painless visualization of the entire gastrointestinal tract and is currently the only diagnostic technology that can examine the whole length of small intestine. The research in this thesis focuses on two communication technologies, Ultra-Wideband and Human Body Communication, that can meet the higher data rate and lower communication power consumption requirements for the next generation capsules. For UWB, a statistical pathloss model, incorporating antenna orientation and body tissue impact, was obtained using a developed 3D immersive platform with a detailed computational model, practical antennas, and an innovative methodology that enables judicious placement of the capsule inside the small intestine. Partial model verification and the impact of the measurement points distribution on the pathloss exponent was also presented. The obtained pathloss was contributed to the IEEE revision of BAN standard and accepted as a standard channel model document for capsule endoscopy use-case. Time domain analysis was preformed to characterize the channel and analyze multipath propagation. In addition, the algorithms to estimate the orientation of the capsule inside the small intestine using a received signal strength were developed. To study HBC, a parametric FEM-based platform including a full 3D computational human body model was developed. This customizable platform allows comprehensive study of the HBC channel by considering different electrode sizes and placements on the surface and inside the body.