The technological advances of recent years have increased the number of users using communication networks, especially with multimedia services such as IPTV, video conferencing and VoIP. As these services generate a large demand on the network infrastructure, the communication networks for wireless broadband, based on the IEEE 802.16 standard, known as WiMAX, meet the various demands of end users, such as the need for access to data at all times, anywhere, and efficient broadband connection. The guarantee of quality of services is a major factor for the performance of communication networks, for this, the scheduling mechanisms, call admission control and traffic policing, should be present. Considering that the IEEE 802.16 standard specifies the mechanisms of how these policies should be implemented, this article aims to present a new scheduler for uplink traffic, with guarantee of quality of services, using the meta-heuristic particle swarm optimization to calculate the duration of time frame, and it is possible to find an optimal value to provide a better allocation of network users.

IEEE 802.11e Medium Access Control (MAC) is a supplement to the IEEE 802.11 Wireless Network (WLAN) standard to support Quality of Service (QoS). The 802.11e MAC defines a new coordination function, namely Hybrid Coordination Function (HCF), which takes the QoS requirements of flows into account and allocates Transmission Opportunity (TXOP) to stations. On the basis of mean sending rate, delay of Variable Bit Rate (VBR) traffic cannot be bounded with the reference HCF scheduling algorithm proposed in this supplement. In this paper, we propose a new scheduling algorithm that utilizes the token bucket and a modified Latency-Rate (LR) scheduling algorithm to guarantee a bounded delay for HCF Controlled Channel Access (HCCA). The new Service Interval (SI) is calculated to optimize the number of stations accommodated and takes into account delay bound and token bucket parameters. We show that is possible to obtain worst-case performance guarantees on delay.First, we analyze the behavior of the proposed scheduler with a loss free wireless channel model and after this, with a burst loss model and we explain how it is possible to extend this scheduler for a multi-rate scheme. Properties of the proposal are investigated both theoretically and using ns-2 simulations. We present a set of simulations with both Constant Bit Rate (CBR) and VBR flows and performance comparisons with HCF scheduling algorithm. The results show that the delay upper bound can be achieved for a large range of networks load with bandwidth optimization.

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