Multiuser diversity with binary feedback

In this paper, we propose a scheduling algorithm that reduces the feedback load with no penalty loss in the spectral efficiency when compared to the optimal selective diversity scheme (Harthi et al. in IEEE Trans Wirel Commun 6(1), 2007). In order to reduce the feedback rate, a two stage probing technique is introduced. In the first stage, the scheduler estimates the threshold level in which the best user is likely to be found. In the second stage, the scheduler permits two users to contend for a mini-slot using only one bit of feedback information per user. After deriving closed-form expressions for the feedback load, we compare the performance of our algorithm with the discrete rate switch-based multiuser diversity (DSMUDiv) scheme (Harthi et al. in IEEE Trans Wirel Commun 6(1), 2007) and the optimal selective diversity scheme. Numerical results show that our scheme further reduces the feedback load, rate and guard time when compared to both the DSMUDiv and the optimal selective diversity schemes under slow Rayleigh fading assumption.