Capacity analysis for dual-hop cooperative system with multiuser scheduling in Nakagami-m fading channels

Cooperative communication significantly increases the coverage area and enhances the system capacity with the help of relay nodes, whereas multiuser diversity is an important technology to improve spectral efficiency in multiuser system. In this paper, we study the multiuser diversity for a dual-hop cooperative system over Nakagami-m fading channels and derive some analytical expressions of system capacity for amplify-and-forward (AF) and decode-and-forward (DF) protocols. Some numerical results are presented for different Nakagami fading parameter m and user number K. The numerical results show that the derived analytical expressions can provide very well approximations to the simulation results. Moreover, both the theoretical and simulation results indicate that the smaller m yields lower capacity when K is small. However, when K becomes large, the system capacity increases as m decreases.