Network code design for orthogonal multi-user channel with broadcasting relay: A joint source channel network coding approach

In this paper, a joint source channel and network coding approach to network code design in an orthogonal multiuser channel with a broadcasting relay is presented. The network consists of a source communicating with several destinations with the assistance of a single instantaneous relay. The relay receives the source transmissions and broadcasts to all the destinations. Aiming at a complexity limited solution, we design the proper instantaneous code (mapping) at the relay to minimize the average reconstruction distortion at the destinations. To this end, by decomposing the source and channel-network distortions, an efficient design algorithm is presented. A motivating formulation for a family of structured nonlinear network codes for given rates of source and relay is also proposed. Numerical results and comparison with linear network coding at the relay and the corresponding rate-distortion bound demonstrate the effectiveness of the proposed schemes and a promising research direction.