Rateless Raptor Codes for Reliable Wireless Capsule Endoscopy (WCE)

Wireless Capsule Endoscopy (WCE) has established as painless endoscopic imaging of the gastrointestinal (GI) tract. To improve the performance of video transfer, we propose a rateless Raptor coding scheme with low coding rate to overcome the potential interference from other signals due to the low-power transmission characteristic of the WCE communications. In addition, the proposed Raptor codes with rateless capability can protect the information from error under varying channel conditions between capsule and the receiver outside the body. The proposed Raptor codes are constructed from Low-Density Parity Check (LDPC) and Luby Transform (LT) codes suitable for short block length of WCE applications such that the rateless capability of the codes can adapt to the dynamic GI channel modeled by multipath In-Body-to-On-Body (IB-to-OB) ultra wide band (UWB) channels in the 3. 4-4.8GHz. We also evaluate the performance of the codes under the multipath channel model for WCE using Cyclic-Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) in terms of average bit error rate (BER) using a series of computer simulations. The results confirmed that the proposed rateless Raptor codes can adapt Well to the dynamic changes of channel conditions and are suitable for practical reliable WCE applications.