User Capacity of Rician and Nakagami Fading Broadcast Channels

In this paper, we extend the results on the maximum number of active users maintaining minimum rate R_min > 0 in broadcast channels, known for Rayleigh fading to the cases of Rician and Nakagami fading models. Under the assumption of independent Rician fading channels for different receivers, as the total number of receivers n goes to infinity, the maximum number of active receivers is shown to be equal to ln(2P In n)/R_min with probability approaching one, where P is total transmit power. For broadcast channels with Nakagami fading, the maximum number of active receivers is shown to be equal to ln(omega/mu P In n)/R_min with probability approaching one, where omega and mu are the Nakagami distribution parameters. A by-product of the results is to also provide a power allocation strategy that maximizes the total throughput subject to the rate constraints.