Transmitter cooperation by joint dirty paper coding in ad-hoc networks

In wireless ad-hoc networks, users cooperate to transmit each others' messages. To some extent terminals therefore collectively act as an antenna array and create a virtual or distributed multiple-input multiple-output (MIMO) system. In order to mitigate interference at receivers, the dirty paper coding (DPC) schemes for various relaying schemes have become very important. In contrast to the conventional scheme that designs the reconstructed signal using DPC technique for each terminal, respectively, we propose a new scheme called joint dirty paper coding for decode-and-forward (DF) cooperative networks. The transmitter forms the reconstructed signal sequence based on its own signal and its partner's signal in terms of DPC technique. The precoding functions of transmitters are considered together, and interference is canceled at the receiver during the superposition of two signal sequences from the transmitter and its partner. The corresponding numerical results prove that, the gap between our proposed scheme and the perfect system without interference can be quite small. The proposed scheme can lead to a superior performance in the sense of frame error rate (FER), which improves as the power allocation ratio increases.