QoS Support by Using CDF-Based Wireless Packet Scheduling in Fading Channels

In this paper, we provide an efficient quality-of-service (QoS)-guarantee scheme using the cumulative-distribution-function-based scheduling (CS) algorithm in wireless fading channels. We first extend the CS algorithm such that it can encompass the practical environment with discrete user transmission rates. The extended CS algorithm can allocate the time fractions to users in arbitrary manner, and render an exact estimation of user average throughputs, through which it can provide differentiated QoS to each user. We also introduce the effective-capacity concept to describe the delay-constrained capacity of the CS algorithm, both in time-independent and time-correlated channels. In contrast to other existing scheduling algorithms, the CS algorithm enables calculating the effective capacity analytically, rather than estimating it by measurement on the queueing behavior. Using the effective capacity, we can check the feasibility of the user-specified QoS effectively in wireless time-varying channels