Proposta de um esquema para a provisão de QoS no padrão IEEE 802.16

Abstract

The IEEE 802.16 standard is designed to provide wireless broadband connectivity for both xed and mobile users in a wide coverage area with high rates of data transfer. The main feature incorporated by the IEEE 802.16 standard is the quality of service (QoS) provisioning by means of packets scheduling, trac policing and connection admission control (CAC). Since the IEEE 802.16 standard does not dene the policies for admission control and packet scheduling, in this paper we propose a QoS provisioning mechanism which consists of a novel scheduling algorithm for uplink trac and a dynamic CAC scheme for IEEE 802.16 networks. The proposed scheduling mechanism serves the requests queues in a cyclical mode and is based on a static bandwidth reservation mechanism in order to separate the real-time and non real time ows. The CAC policy is proposed for the real-time service class with variable rate and is based on a delay prediction scheme which uses the buer size information in SSs. Through modeling and simulation, we evaluated various network scenarios in order to test the eciency of CAC and scheduling mechanism. From the results, it was found that the proposed mechanism is able to meet the maximum delay requirements of the maximum delay bound for real time ows and minimum throughput for streams of non-real time. Moreover, it was found that the proposed mechanism is able to avoid the bandwidth starvation of low priority ows.