Decode-and-Forward Cooperative Protocol for Multiuser Communication Systems

Cooperative diversity is a promising solution for diversity gain, multiplexing gain and energy saving. This technique involves multiple users sharing resources in order to build a virtual antenna array in a distributed manner. In this paper, we propose multi-user cooperation strategy that allows multiple users to transmit their data simultaneously in decode-and-forward relaying systems. We consider non-orthogonal transmission scenario where users interfere each other. The proposed protocol is well-configured to cope with the interfering scenario. We introduce 3-user cooperation strategy and extend the protocol to arbitrary N-user cooperation strategy. Analytical results show that proposed scheme achieves diversity order of 2 without any loss of multiplexing gain while conventional schemes experience half-loss of multiplexing gain or have several drawbacks. We confirm through computer simulations that the proposed protocols provide higher data rate with more reliability than the conventional schemes.