An On-Line Decoding Algorithm for 3GPP MBMS Raptor Codes

This paper presents an On-line Gaussian Elimination (OGE) decoding algorithm for 3GPP MBMS Raptor, which can fundamentally shorten the decoding time. As we know, in Gaussian Elimination based Raptor decoding algorithm, calculations start after all data needed have been received. While in the proposed OGE algorithm, decoding calculations are advanced to the moment that only several encoded symbols have been received. By doing so, most of decoding work could be finished during receiving stage and only a small amount of post-processing needs to be done after receiving. Therefore, the period usually used for decoding could be shortened dramatically. Simulation results show that for all kinds of decoding scenarios, OGE algorithm could always shorten the decoding time to less than 1% that of 3GPP Raptor standard decoding algorithm while maintaining the same decoding performance.