Aymen Belghith

Comparison of WiMAX scheduling algorithms and proposals for the rtPS QoS class

Scheduling algorithms are of utmost importance in WiMAX for efficient use of radio resources. A scheduling algorithm should take into account the WiMAX QoS classes and service requirements. It should also provide high throughput. In this paper, we propose a review of scheduling algorithms proposed for WiMAX. We focus on the real-time Polling Service (rtPS) QoS class. NS-2 simulations show interesting results. We highlight a problem that may exist with the WiMAX rtPS QoS class and we provide solutions for it. Simulation results concerning proposed WiMAX schedulers are discussed. We propose an enhancement of the maximum Signal-to-Interference Ratio (mSIR) scheduler, called modified maximum Signal-to-Interference Ratio (mmSIR). We show through extensive simulations that this enhancement provides better mean sojourn time in addition to an improvement in throughput.

Design and implementation of a QoS-included WiMAX module for NS-2 simulator

WiMAX is a very promising technology. The main promises are the high throughput and the large coverage. As for all new technologies, performance studies are required. The network simulation is considered as a solution to test the performance of technologies and especially the wireless networks. In this paper, we propose a new WiMAX module for NS-2 simulator. This module is based on the NIST implementation of WiMAX [5]. Our contribution consists of the addition of the QoS classes as well as the management of the QoS requirements, unicast and contention request opportunities mechanisms, and scheduling algorithms for the UGS, rtPS and BE QoS classes. Simulation results provide interesting observations about the throughput and mean sojourn time values. Simulation results show that our UGS, rtPS, and BE schedulers are in accordance with the specification of the QoS classes defined in the IEEE 802.16 standard.

Pricing of Differentiated-QoS Services WiMAX Networks

WiMAX/IEEE 802.16 system is a very open Broadband Wireless Access (BWA) technology with different possible services. Pricing of WiMAX is an important topic with different optimization possibilities. In a previous paper, we investigated WiMAX pricing for real-time applications (Unsolicited Grant Service (UGS) and real-time Polling Service (rtPS) QoS classes of WiMAX). We add the Best Effort (BE) QOS class in this paper in order to have a rather complete WiMAX environment. The system model is described. Then we consider two different BE pricing mechanisms: fixed price and auction-based variable price. The proposed methods are evaluated through simulations in order to have some interesting comments and highlights for WiMAX pricing.

WiMAX Capacity Estimations and Simulation Results

In this paper, we propose some considerations for the WiMAX capacity. The developments realized for a WiMAX NS-2 module are presented. This module allows the evaluation of the WiMAX. We present the spectrum efficiency and mean sojourn time of WiMAX determined through simulations for different scheduling algorithms. It is then possible to compare theoretical values and simulation results of WiMAX spectral efficiency and highlight some interesting comments. This is done for two proposed scenarios.

Pricing of Real-Time Applications in WiMAX Systems

WiMAX/IEEE 802.16 broadband wireless access (BWA) is a very open technology with different possible services that is likely to be widely used in metropolitan access networks in the near future. While the technical aspects of that technology are now quite well established, the economic implications of the introduction of WiMAX technology have received little attention. In this paper, we consider the problem of pricing WiMAX sessions: we propose some simple pricing mechanisms aimed at coping with congestion while maintaining a sufficient quality of service and/or yielding a sufficient revenue to the operator. Our mechanisms are evaluated under a specific model of user preferences and WiMAX situations, and the implications of some parameter choices are observed.

Pricing-Based Schedulers for WiMAX

Scheduling algorithms are very important in WiMAX for the efficient use of radio resources. However, the standard does not specify which scheduling algorithm(s) should be used. A scheduling algorithm should take into account the WiMAX QoS classes and service requirements. The scheduling algorithm also has to taken into account other models of the WiMAX system such as power saving and pricing models. In this paper, we propose schedulers for some QoS classes. These schedulers are designed to include our WiMAX pricing model that we proposed in previous works in our WiMAX framework. We show that the scheduler has to take into account the pricing model used. Moreover, we show that the optimization of resources usage associated with a suitable pricing scheme provides higher revenue for the operator by comparing our sophisticated pricing scheme with a basic one.

Proposal for the configuration of multi-domain network monitoring architecture

In Internet networks, monitoring is necessary to guarantee the performance of the services. In this paper, we review the state-of-the-art monitoring architectures proposed for multi-domain networks. We note that these architectures do not support measurement configuration that enables the providers to perform flexible multi-domain measurements. Therefore, we present our proposal for the configuration of the multi-domain network monitoring architecture in order to give more flexibility in network monitoring and solve the heterogeneity and interoperability problems. We also present our collaboration schemes that can be applied in our configurable monitoring architecture. These collaboration schemes, based on the proactive selection and reactive selection, are used to select the measurement points that participate in the multi-domain monitoring and configure the parameters of the measurement points selected. We show through extensive simulations that the proactive collaboration scheme provides a more flexible multi-domain monitoring and reduces the delay and the overload of the monitoring establishment.

Scheduling Techniques for WiMax

This chapter proposes a state-of-the-art of scheduling techniques for WiMax. We first summarize the practical considerations of a WiMax scheduling algorithm in order to make a link between a scheduling algorithm and its implementation in WiMax. Then, we analyze the proposed use of some known algorithms for WiMax and then some scheduling algorithms specifically proposed for WiMax. Finally, we draw a comparison between the different possible scheduling methods and highlight the main points of each of them.

Efficient Bandwidth Call Admission Control in 3GPP LTE Networks

In Long Term Evolution (LTE) Networks, several call admission control mechanisms were proposed. They take into account some network constraints such as service diversity and availability of radio resources. However, the shortcomings of the existing mechanisms led us to propose a new approach called Efficient Bandwidth Call Admission Control (EB_CAC). Our proposition considers the quality of service (QoS) while trying to maximize User Equipment satisfaction levels and optimize the use of bandwidth. The simulation results show that our proposed solution outperforms other existing mechanisms in terms of number of real time users accepted as well as the system throughput.

WiMAX spectrum efficiency: Considerations and simulation results

Scheduling algorithms are very important in WiMAX allowing an efficient radio resources distribution to the uplink and downlink connections. However, the IEEE 802.16 standard does not specify which scheduling algorithm(s) should be used. In this paper, we propose a review of scheduling algorithms proposed for WiMAX / IEEE 802.16 system. We also propose some considerations for the spectrum efficiency computations of scheduling algorithms in WiMAX. Then, we calculate the satisfaction percentage and spectrum efficiency for three scheduling approaches. Figures are given for three scenarios (pessimistic, optimistic and realistic) allowing interesting observations about WiMAX radio efficiency. These results can be used as an order of magnitude for more sophisticated studies on this important topic. The paper ends with some interesting comments about WiMAX scheduling.