Broadcast channel with transmitter noncausal interference and receiver side information

This work investigates the broadcast channel with the knowledge of noncausal interference at the transmitter and side information at the receivers. The system studied involves one transmitter sending private information to two receivers. We first obtain an achievable rate region of this system by extending Gelfand and Pinsker´s (GP´s) random binning method, originally designed for point-to-point communications. We then apply the result to Gaussian scalar and vector channels, and consider the design of the auxiliary random variable used in GP´s approach. Asymptotic analysis shows that the proposed scheme in both scalar and vector channels is asymptotically capacity-achieving at high signal-to-noise ratio (SNR). We further investigate the system optimization in the finite SNR regime. For the scalar channel, we derive the optimal auxiliary factor that maximizes the weighed sum-rate. For the vector channel, two kinds of suboptimal designing methods for the auxiliary matrix are proposed. Numerical results show that the proposed scheme can achieve a sum-rate close to the cut-set bound in the entire SNR regime, and significantly outperforms the schemes that do not exploit the knowledge of noncausal interference known at the transmitter.