Impact of Overhead on Spectral Efficiency of Cooperative Relaying

It is well known that cooperative relaying has the potential to improve the performance of wireless communication. However, compared with point-to-point communication, cooperative relaying requires much more overhead to implement. In this paper, we quantitatively analyze the overhead in implementing cooperative relaying, in particular, the overhead to acquire essential channel state information, to select the relay(s), and to provide the required coordination. Factoring in the impact of overhead, the spectral efficiency of cooperative relaying schemes is then investigated. A comparison of three cooperative relaying schemes (Timer-Based Best-Select, Distributed Space-Time-Coded, and M-group) is presented. Numerical results are provided to illustrate the impact of overhead on the spectral efficiency. Finally, based on the analysis and simulations, we provide guidelines for determining the appropriate cooperative relaying scheme for specific scenarios.