TCP performance in the GPRS system adopting the channel quality aware scheduler

The General Packet Radio Service (GPRS) networks are already implemented by several companies in different countries, however some problems related to the quality of service (QoS) observed by users and the efficient use of radio resources are not yet adequately addressed. In this framework, we propose a scheduling algorithm implemented at MAC layer, named as channel quality aware scheduler (CQAS). The main feature of the CQAS is that the user to serve is established taking into account the estimated channel quality for each of the active traffic flows. The performance of the proposed algorithm are evaluated in terms of goodput experimented by TCP clients, considering a set of concurrent file transfers and independent time varying channels. The comparisons between the CQAS performance and those obtained using a simple work conserving round robin (WCRR) algorithm, highlight the improvements introduced by the proposed algorithm. Moreover, the analysis emphasizes that the appropriate choice of both the channel coding scheme (CS) and the scheduling algorithm is needed in order to increase the radio resource utilization