Raptor Coding for Non-Orthogonal Multiple Access Channels

In this paper, we propose a scheme for increasing the capacity of a communication channel by overloading a pre-existing channel with a controlled interfering channel using Raptor code. Combination of Raptor code and use of interference cancellation in the resulting Multiple Access Channel (MAC) results in almost perfect removal of the effect of the interfering channel. Thus, the primary channel´s performance remains intact. As in the other MAC detection scenarios, for optimal performances, a power difference between the main and interfering transmitters is required. In the case that these two powers are equal, we propose a hard decision stage prior to the decoding at the destination in order to eliminate erased symbols. The proposed technique can also be used for increasing the capacity of forward and/or return links of the DVB Return Channel via Satellite (DVB-RCS).