Review of WiMAX Scheduling Algorithms and Their Classification

摘要

Providing quality of service (QoS) in wireless communication networks has become an important consideration for supporting variety of applications. IEEE 802.16 based WiMAX is the most promising technology for broadband wireless access with best QoS features for tripe play (voice, video and data) service users. Unlike wired networks, QoS support is difficult in wireless networks due to variable and unpredictable nature of wireless channels. In transmission of voice and video main issue involves allocation of available resources among the users to meet QoS criteria such as delay, jitter and throughput requirements to maximize goodput, to minimize power consumption while keeping feasible algorithm flexibility and ensuring system scalability. WiMAX assures guaranteed QoS by including several mechanisms at the MAC layer such as admission control and scheduling. Packet scheduling is a process of resolving contention for bandwidth which determines allocation of bandwidth among users and their transmission order. Various approaches for classification of scheduling algorithms in WiMAX have appeared in literature as homogeneous, hybrid and opportunistic scheduling algorithms. The paper consolidates the parameters and performance metrics that need to be considered in developing a scheduler. The paper surveys recently proposed scheduling algorithms, their shortcomings, assumptions, suitability and improvement issues associated with these uplink scheduling algorithms.