Rateless Coded Vector OFDM System for Transmission over Doubly Selective Fading Channels

A joint modulation and coding scheme is proposed based on Rateless Codes and Vector OFDM systems to combat fading over doubly selective channels. A rateless encoder can generate potentially unlimited coded symbol. Vector OFDM is a general transmission scheme, where OFDM and Single-Carrier systems can be seen as two extreme cases. The main focus of this paper is to design and analyze a Rateless Coded Vector OFDM scheme to obtain extra gain and improve the system performance. Firstly, we derive the lower bound of the decoding complexity of the block universal Raptor Codes and the upper bound of the probability to decode successfully in Binary Erasure Channels. Secondly, we analyze the joint scheme of Rateless Coded Vector OFDM with a novel proposition proposed, which reveals the impacts of the degree distribution on the system performance. According to the proposition, two practical Rateless Coded Vector OFDM methods are presented, which can achieve considerable joint Multipath-and-Doppler diversity gain and coded modulation gain to improve the reliability of the system. Finally, simulation results are demonstrated to validate the proposed scheme.