Qualidade de serviço em redes IEEE 802.16: como agendar tráfego para cumprir os requisitos QoS de classes heterogêneas de tráfego

Abstract

The huge commercial success of mobile telephony, the continuous growth of Internet users and mobile Internet users, as well as the wide spreading of IP-based multimedia applications play an important role to the development of the third generation wireless networks. These networks are also known as 3G – digital technology that supports voice, data, multimedia and Internet broadband servisse through packet commutation. The concept of a forth-generation network is already being discussed, which is based upon a unification of several different wireless networks. In this scenario, WIMAX (IEEE 802.16) comes out as the promise for this unification (specialists predict that until 2012 WIMAX will be a market reality). The WIMAX is a metropolitan broadband wireless network solution for the “last mile“ problem. The IEEE 802.16 standard was devised to users who want access to high quality multimedia services and a system with high availability too. Keeping this in mind, this standard specifies the mac and physical layer to offer a mechanism to efficiently share the air medium with QoS guarantees through service flow scheduling mechanisms. These mechanisms are able to distinguish between these flows, as well as to organize them. However, in IEEE 802.16 MAC protocols some issues are not addressed. One of these issues is how to combine efficiently bandwidth request strategy and bandwidth allocation (scheduling) strategy to maintain QoS and fairness for different traffic. Another issue is that high priority requests cannot be distinguished during first access and they may keep colliding with low priority requests. This work presents a suggestion of GuoSong et al [1] to solve some of these issues.