Low Overhead Spectral Efficient Cooperative Relaying Protocols

We propose two high spectral efficient relaying protocols with low overhead including: the priority based relay selection (PRS), and the priority based relay selection with incremental transmission (PRSIT). In PRS and PRSIT, relay selection and scheduling are integrated to achieve full diversity order and high spectral efficiency. We define the overhead per allocated time slot for a user as the number of required signaling bits for channel estimation and implementing corresponding communication procedures. It is shown that the overhead of our proposed protocols is a logarithmic function of the number of users, thus they have much lower overhead comparing to the other high spectral efficient cooperative protocols such as opportunistic relaying (OR) and OR with incremental transmission in which their overhead is a linear function of the number of users. Simulation results show that with much lower overhead, PRS and PRSIT either outperform or act closely to the existing cooperative