Adaptive scheduling mechanism for IPTV over WiMAX IEEE 802.16j networks

Abstract

A WiMAX technology is a very promising Broadband Wireless Access technology that is able to transmit different service types. This latter can have different constraints such as traffic rate, maximum latency, and tolerated jitter. The IEEE 802.16 Medium Access Control specifies five types of QoS classes: UGS, rtPS, ertPS, nrtPS, and BE. However, the IEEE 802.16 standard does not specify the scheduling algorithm to be used. Operators have the choice among many existing scheduling techniques. Also, they can propose their own scheduling algorithms. In this paper, we propose a scheduling strategy (Adaptive Weighted Round Robin, AWRR) for various Internet Protocol Television (IPTV) services traffic over 802.16j networks. Our scheme adapts dynamically the scheduler operation to according queue load and quality of service constraints. In particular, the proposed mechanism gives more priority to high definition television and standard definition television traffic by using two schedulers. The proposed scheduling algorithm has been simulated using the QualNet network simulator. The experimental results show that our scheduler schemes AWRR have a better performance than the traditional scheduling techniques for rtPS traffic, which allows ensuring QoS requirements for IPTV application.Unsolicited grant service (UGS): such as T1/E1 transport. It requires reserved traffic rate, maximum latency, and tolerated jitter. Extended real-time polling service (ertPS): such as voice of IP (VoIP). It is built on the efficiency of both UGS and rtPS, reduces overhead and access delay of rtPS, and improves uplink resource utilization of the UGS. As a subcategory of rtPS, ertPS has the same QoS parameters as rtPS in the scheduler design. Real-time polling service (rtPS): such as MPEG audio/video streaming and video conferencing. It supports variable bit rate traffic via minimum reserved and maximum sustained traffic rates and requires tolerable stringent latency constraints. Non-real-time polling service (nrtPS): delay tolerant streams with variable-sized packets, for which only minimum reserved and maximum sustained traffic rates are required, such as File Transfer Protocol (FTP). Best effort (BE) service: such as HTTP and email. BE services are handled on a space available basis and do not require tight latency/jitter constraints, with upper limited bandwidth consumption via maximum sustained traffic rate.

A load-aware weighted round-robin algorithm for IEEE 802.16 networks

“…Adaptive weighted round robin (AWRR) is yet another variant, proposed by [24], again to avoid the problem of starvation of lower priority classes. It uses two schedulers: an input scheduler aims to prioritize video streams with superior quality (HD and SD) and consists of a high-priority (HP) buffer for, e.g., UGS, ertPS, and rtPS, and a low-priority (LB) buffer, which includes rtPS-web-TV, rtPS-mobile-TV, nrtPS, and BE.…”

An Efficient Study of Scheduling Algorithms with Freidman Test in WiMAX Networks

“…The objective of this technique is to dynamically adjust the weight of each queue in relation to those two criteria above. This technique is called Adaptive Weighted Round Robin (AWRR) [9]. The weight management mechanism is provided by a system of equations which is based on the detection of a crossing certain threshold that anticipates congestion packet loss due to queue overflow.…”

“…Using this scheduler does not have affect with the processing time, as the data packets have a removal time before they are processed by the main scheduler. We recall from our previous work [9], Figure 1 shows the overall architecture of proposed scheduler with specifying different queues. The proposed algorithm applies AWRR on both schedulers (input and output) to adjust the weight of each service class.…”

Software Network Simulators for IPTV Quality of Services

“…Adaptive scheduling mechanism for IPTV has better performance than the traditional scheduling techniques for rtPS traffic [9]. In QualNet, a specific network topology is referred to as a scenario.…”