Smart Cooperation through Orthogonal Signaling and Optimal Power Allocation

In this paper, a novel cooperative transmission scheme based on orthogonal signaling is proposed for two-user cooperative systems. Compared to the traditional cooperation alternatives, in our scheme, each user utilizes the in-phase and quadrature components of the QPSK signal constellation to forward its own information as well as the partner´s. The approximate closed form of its frame-error-rate (FER) is derived and the principle of the optimal power allocation is also provided. Simulation results demonstrate that our proposed scheme outperforms traditional alternatives and can still achieve satisfiable FER performance even in low inter-user channel quality due to the power adjustment.