Proc. of the International Symposium on Wireless personal Multimedia Communications, San Diego, CA, Sept. 17-20, 2006.
This paper proposes a random access based feedback protocol for
the clustered orthogonal frequency division multiplexing (OFDM)
downlink, which allows users to feed back their 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. Active users send a 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 a tight upper bound to the average
sum rate of all users. The main advantage of this protocol is that
it achieves multiuser diversity with only a small amount of
This paper is available as a IEEE Xplore .