On the rate constraint of transmitting multiple priority classes with QoS

The rate constraint of transmitting multiple priority classes over a time-varying service-rate channel is studied in this work. This constraint specifies the maximum data rate that can be transmitted reliably with QoS (quality of service) guarantee. In our framework, the time-varying service channel is modeled by an N-state discrete Markov process, where each Markov state is associated with a channel service rate, and the absolute priority scheduling is used to transport packets of different classes. The transmission rate constraint is derived based on effective bandwidth and capacity. To be more specific, given channel parameters and the maximum buffer size for each priority class, statistical QoS guarantees in terms of packet loss probabilities can be determined and translated to the transmission rate constraint. The derived result is verified by simulation in a time-varying wireless environment.