On Approximating Throughput in Wireless Systems with Complex Rate Variability and QoS

Beyond 3G wireless systems will support real time and elastic traffic over a common packet-switched radio channel using QoS mechanisms. This paper studies the key question of how to estimate the throughput performance of "best effort" elastic traffic when it is subject to available capacity variations due to changes in (i) the amount of higher priority traffic and (ii) the radio channel. We extend previous work in this area to show that for the QoS mechanisms studied, an equivalent PS model provides a good closed-form approximation to call-average throughput, with desirable properties of independence from radio channel variations and best effort call volume distribution. Our findings therefore provide a basis for practically estimating throughput performance of best effort traffic with arbitrary call volume distribution, in radio systems with multiple QoS levels and complex rate variability.