Utilizing multiuser diversity for efficient support of quality of service over a fading channel
IEEE International Conference on Communications, 2003. ICC '03.
We consider the problem of quality of service (QoS) provisioning for K users sharing a downlink timeslotted fading channel. We develop simple and efficient schemes for admission control, resource allocation, and scheduling, which can yield substantial capacity gain. The efficiency is achieved by virtue of recently identified multiuser diversity. A unique feature of our work is explicit provisioning of statistical QoS, which is characterized by a data rate, delay bound, and delay-bound violation
... probability triplet. The results show that compared with a fixed-slot assignment scheme, our approach can substantially increase the statistical delay-constrained capacity of a fading channel (i.e., the maximum data rate achievable with the delay-bound violation probability satisfied), when delay requirements are not very tight, while yet guaranteeing QoS at any delay requirement. For example, in the case of low signal-to-noise-ratio (SNR) and ergodic Rayleigh fading, our scheme can achieve approximately K k=1 1 k gain for K users with loose-delay requirements, as expected from the classic paper  on multiuser diversity. But more importantly, when the delay bound is not loose, so that simple-minded multiuser-diversity scheduling does not directly apply, our scheme can achieve a capacity gain, and yet meet the QoS requirements.