Proposta de algoritmo de controle de admissão de conexões baseado em Threshold para as Redes IEEE 802.16

Abstract

IEEE 802.16 standard, also called WiMAX (Worldwide Interoperability for Microwave Access), is one of the most promising technologies for BWA (Broadband Wireless Access) networks. The IEEE 802.16 standard provides specification of MAC and physical layer. The standard adds to the BWA networks some advantages over other technologies, such as wide area of coverage, even in areas of difficult access or without conventional network infrastructure, as is the case of some urban and rural regions in Brazil. IEEE 802.16 standard is developed with Quality of Service (QoS) in mind. For that purpose it was created a connection oriented standard, where different applications are differentiated into multiple classes of service, in accordance with the parameters required by each application. However, the standard does not define how to implement the Connection Admission Control (CAC) algorithm, which is a fundamental requisite for obtaining QoS. The CAC algorithm is responsible for accepting or rejecting a new connection request depending on the resources already allocated in the network. Thus, the CAC must reject requests for connections that might compromise the QoS of admitted connections. This way, this work presents the proposal of a CAC algorithm based on threshold for the IEEE 802.16 networks. Moreover, the performance of the proposed CAC algorithm has been analyzed through modeling and simulation using the NS-2 (Network Simulator). To perform this step, the proposed CAC algorithm has been implemented in the WiMAX module of the NIST (National Institute of Standards and Technology). The results showed that the CAC algorithm is efficient and it is able to provide QoS in terms of bandwidth and delay, under different scenarios.