Scheduling in CDMA-based wireless packet networks.

Abstract

Modern networks carry a wide range of different data types, each with its own individual

requirements. The scheduler plays an important role in enabling a network to meet all

these requirements. In wired networks a large amount of research has been performed

on various schedulers, most of which belong to the family of General Processor Sharing

(GPS) schedulers. In this dissertation we briefly discuss the work that has been done on a

range of wired schedulers, which all attempt to differentiate between heterogeneous traffic.

In the world of wireless communications the scheduler plays a very important role, since

it can take channel conditions into account to further improve the performance of the

network. The main focus of this dissertation is to introduce schedulers, which attempt to

meet the Quality of Service requirements of various data types in a wireless environment.

Examples of schedulers that take channel conditions into account are the Modified Largest

Weighted Delay First (M-LWDF), as well as a new scheduler introduced in this dissertation,

known as the Wireless Fair Largest Weighted Delay First (WF-LWDF) algorithm.

The two schemes are studied in detail and a comparison of their throughput, delay, power,

and packet dropping performance is made through a range of simulations. The results are

compared to the performance offour other schedulers. The fairness ofM-LWDF and WFLWDF

is determined through simulations. The throughput results are used to establish

Chernoff bounds of the fairness of these two algorithms. Finally, a summary is given of the

published delay bounds of various schedulers, and the tightness of the resultant bounds is

discussed.