Scheduling algorithms in broadband wireless networks

Abstract

Scheduling algorithms that support quality of service (QoS) differentiation and guarantees for wireless data networks are crucial to the development of broad-band wireless networks. Wireless communication poses special problems that do not exist in wireline networks, such as time-varying channel capacity and location-dependent errors. Although many mature scheduling algorithms are available for wireline networks, they are not directly applicable in wireless networks because of these special problems. This paper provides a comprehensive and in-depth survey on recent research in wireless scheduling. The problems and difficulties in wireless scheduling are discussed. Various representative algorithms are examined. Their themes of thoughts and pros and cons are compared and analyzed. At the end of the paper, some open questions and future research directions are addressed.

Feedback Closed-Loop Scheduling Discipline for QoS Guarantee in Mobile Applications

“…Various WFQ-based algorithms developed from the errorfree service model, the lead/lag model, the compensation model and slot/packet queue decoupling, have been proposed for adapting fair queuing to the wireless domain [5][6][7]20,21]. The error-free service model provides a reference for how much service a flow should receive in an ideal error-free channel environment.…”

QoS maintenance for fair queueing algorithms in wireless mobile networks

“…Recently, new propositions and schemes for packet scheduling in wireless networks have emerged by partially adopting the fair queueing algorithms developed for wireline networks [7][8][9][10][11][12].…”

“…Much of the research has been devoted to improve the performance of fair queueing algorithms in terms of delay, fairness and complexity related with the virtual time function and maintaining and sorting time stamps. Recently, new propositions and schemes for packet scheduling in wireless networks have emerged by partially adopting the fair queueing algorithms developed for wireline networks [7][8][9][10][11][12].…”

“…Fair queueing is useful for providing QoS in an integrated services networks, since if combined with admission control, it provides fairness, minimum bandwidth guarantee and bounded end-to-end delay [2]. With the rapid growth in popularity of wireless data services and the increasing demand for multimedia applications, it is expected that future wireless networks will provide services for heterogeneous classes of traffic with different QoS requirements [7]. To this end an important research issue is to extend the QoS service models and algorithms developed for wireline networks to wireless networks.…”

QoS Differentiated and Fair Packet Scheduling in Broadband Wireless Access Networks

“…The capacity of wireless channel usually suffers either moderate or drastic fluctuations due to the signal attenuation, interuser interference, fading and user mobility, and so forth. As a result, the channel conditions of users may vary with time and location asynchronously at random, leading to the socalled time-dependent error and location-dependent error [1]. In BWA networks, the process of packet arrivals is generally complicated and hard to accurately model in advance, since the packet arrivals are induced by the aggregation of multiple classes of traffic with different properties, such as constant and variable rates, and continuous and burst modes.…”