On the Multi-Rate Division with Limited Feedback for One Source Multiple Destinations Wireless Transmission Systems

Multiuser diversity is inherent in wireless networks due to independent channel variations of different users. It requires that the transmitter has the knowledge of the channel state information (CSI) of each user in the downlink. Too much feedback will bring a heavy load to the system in some cases. This paper investigates the problem of exploiting multiuser diversity in a one source multiple destinations wireless transmission system with limited feedback. A strategy for obtaining the optimal multiple rate level and the maximum achievable sum rate is proposed in this paper. Moreover, the scheduling outage probability, the probability that rates of all users are below a threshold, is also analyzed. For one-bit feedback, a tight bound of the achievable rate is obtained. It is shown that the achievable rate nearly capture the order of the double-logarithmical of the number of users in full CSI systems. Numerical results are also presented. The achievable sum rate is close to the full CSI capacity via limited feedback as the number of users is large enough.