Opportunistic Scheduling in Multiuser OFDM Systems with Clustered Feedback



Taiwen Tang, C.B.Chae, Robert W. Heath Jr., S.H.Cho, and S. Yun


Submitted to Wireless Personal Communications Journal, Jan., 2007


This paper proposes a random access based feedback protocol for the multiuser orthogonal frequency division multiplexing (OFDM) system with clustered feedback, which allows users to feed back their representative channel information to the base station (BS) in a distributed fashion. The proposed protocol employs a contention channel that consists of fixed amount of system resource to carry the feedback for each cluster. We also propose two different feedback messages for the clustered feedback. Active users send the feedback message with some probability if their average channel quality on one cluster is above a threshold. The threshold and feedback probability are jointly adjusted to maximize the estimated average sum rate of all users based on two different limited feedback information. The main advantage of this protocol is that it achieves multiuser diversity with only a small amount of feedback overhead.

This preprint is available on email request.