Trellis shaping based dirty paper coding scheme for the overlay cognitive radio channel

In this paper, we propose a dirty paper coding (DPC) scheme that uses trellis shaping for the overlay cognitive radio channel, where a cognitive user and a primary user transmit concurrently in the same spectrum. Interference of the primary user is assumed to be known at the cognitive transmitter non-causally. Based on this knowledge, the shaping code selection, as a key feature of the proposal, is introduced which enables the constellation to be self adaptively changed. The performance of our proposed scheme is compared using simulations with that based on the conventional trellis shaping and it achieves excellent tradeoff between performance and complexity.