On analyzing the intra-frame power saving potentials of the IEEE 802.16e downlink vertical mapping

Worldwide Interoperability for Microwave Access (WiMAX) is generally considered as a competitive candidate networking technology for the realization of the 4G vision. Among the key factors towards its successful and widespread deployment are the effective support of mobility and the provision of mechanisms for enabling service access at a high quality level in an efficient and cost-effective manner. Nonetheless, this effort should take into account and adequately address strict and severe energy limitations that the mobile devices are currently facing. Power saving constitutes an issue of vital importance, as mobile terminals continue to incorporate more and more functionalities and energy-hungry features in order to support the ever increasing user requirements and demands. The standard employs variations of power saving classes in a frame-to-frame basis, while recent power saving mechanisms proposed in related research literature limit their activity in whole frames, neglecting, thus, the intra-frame power saving capabilities. In this work, the intra-frame energy conservation potentials of the mobile WiMAX network are studied and a novel analytical approach is provided, focusing on the downlink direction where the bandwidth allocation involves idle intervals and dynamic inactivity periods. Specifically, we endeavour to accurately analyse the potential energy conservation capabilities in an intra-frame point of view, applying the well-known simple packing algorithm to distribute the available bandwidth to the various subscribers. Our analytical findings are thoroughly cross-validated via simulation, providing clear insights into the intra-frame energy reduction capabilities

Modèles analytiques pour le dimensionnement de réseaux cellulaires de quatrième génération

Cette thèse porte sur le développement de modèles analytiques, à la fois précis et simples d'utilisation, adaptés aux problèmes posés par le dimensionnement des réseaux cellulaires 4G (WiMAX et LTE). Les modèles, s'appuyant sur la théorie des files d'attente, permettent d'évaluer les performances d'une cellule 4G et de ses utilisateurs. Dans un premier temps, sont présentés tour à tour des modèles dédiés à chaque type de services et à leurs besoins en QoS respectifs (VoIP, VoIP avec suppression des silences, streaming et WEB). Chacun d'eux est déclinés afin de considérer des cellules contenant plusieurs groupes d'utilisateurs avec différents profils. Dans un second temps, des méthodes sont proposées pour combiner les précédents modèles afin de prendre en compte des cellules avec intégration de services tout en minimisant la complexité de résolution. Tous les modèles ont été pensés afin d'obtenir des expressions à formes closes de l'ensemble des paramètres de performances du système et donc d'être résolus instantanément. Cette rapidité rend possible les études de dimensionnement les plus complètes comme en témoignent les nombreux exemples inclus dans cette thèse. Précisons finalement que de telles études seraient absolument inenvisageables à partir de simulations.PARIS-BIUSJ-Mathématiques rech (751052111) / SudocSudocFranceF

Delay-constrained dimensioning of WiMAX cellular networks carrying multi-profile real-time traffic

Abstract—This paper tackles the challenging task of developing accurate easy-to-use analytical models for performance evaluation of WiMAX networks. The need for precise fastcomputing tools is of primary importance to face complex dimensioning issues of WiMAX cells. Here, we present generic Markovian models developed for the rtPS service class defined in the WiMAX standard. This service class is dedicated to realtime applications with constraints on both their bit rates and the latency of their packets (i.e., streaming). Our analytical modeling is performed in two steps. First, we focus on the connection level only considering the bit rate constraint. Then, we extend the model to the packet level to formulate the packet delay QoS parameter. The resulting models can account for multiple traffic profiles at both levels while always keeping an instantaneous resolution. The models are compared with simulations that show their accuracy. Finally, we show how our models can be used to solve dimensioning issues while avoiding days of simulations

On finding the right balance between fairness and efficiency in WiMAX scheduling through analytical modeling

International audienceIn this paper, we explore a way to find the right scheduling policy for WiMAX networks, that achieves the best compromise between an efficient use of the resource and a relative fairness among users. This problem is of primary importance as no scheduling policy has been recommended in the WiMAX standard. To do so, we develop an extension of our previous analytical model for WiMAX networks, that takes into account a more general scheduling policy than those previously studied (i.e., instantaneous throughput fairness, slot sharing fairness and opportunistic scheduling). We show that this general policy covers the two extreme cases, namely the instantaneous throughput fairness policy and the opportunistic policy, and offers intermediate policies that are good candidates for finding the right trade-off. In order to formulate the decision criterion, we introduce a new performance parameter, the mean throughput obtained by a user depending on its efficiency to use the resource. The model has a closed-form solution, and all performance parameters can be obtained instantaneously. This allows us to carry out dimensioning studies that require several thousands of evaluations, which would not be tractable with any simulation tool

Dimensioning Methodology for OFDMA Networks

International audienceIn this paper, we present a comprehensive methodology to dimension an OFDMA (Orthogonal Frequency Division Multiple Access) network. We divide the dimensioning task into sub-blocks and present implementation details of each block. The first block has the objective of determining the spatial SINR (Signal to Interference plus Noise Ratio) distribution over a cell area and the MCS (Modulation and Coding Scheme) probabilities. This task usually relies on extensive Monte Carlo simulations. In this paper, we propose a semi-analytical approach in order to reduce computational time. The second block evaluates dimensioning parameters based on a markovian approach. Our model takes into account mixed traffic profiles, different scheduling policies and MCS probabilities obtained from the first step. Theses two stages (radio coverage and traffic analysis) form together a complete dimensioning process for OFDMA networks

An Efficient Analytical Model for the Dimensioning of WiMAX Networks Supporting Multi-profile Best Effort Traffic

International audienceThis paper tackles the challenging task of developing a simple and accurate analytical model for performance evaluation of WiMAX networks. The need for accurate and fast-computing tools is of primary importance to face complex and exhaustive dimensioning issues for this promising access technology. In this paper, we present a generic Markovian model developed for three usual scheduling policies (slot sharing fairness, throughput fairness and opportunistic scheduling) that provides closed-form expressions for all the required performance parameters instantaneously. We also present and evaluate the performance of a fourth policy, called throttling policy, that limits the maximum user throughput and makes use of the Maximum Sustained Traffic Rate (MSTR) parameter foreseen by the standard. At last, we extend these studies to multi-profile traffic patterns. The proposed models are compared in depth with realistic simulations that show their accuracy and robustness regarding the different modeling assumptions. Finally, the speed of our analytical tools allows us to carry on dimensioning studies that require several thousands of evaluations, which would not be tractable with any simulation tool.</p

An Analytical Model for WiMAX Networks with Multiple Traffic Profiles and Throttling Policy

International audienceIn this paper, we present a simple and accurate analytical model for performance evaluation of WiMAX networks with multiple traffic profiles. This very promising access technology has been designed to support numerous kinds of applications having different traffic characteristics. One of the QoS parameters considered by the standard for traffic classes is the maximum sustained traffic rate (MSTR), which is an upper bound for user throughput. Taking into account MSTR implies the implementation of a throttling scheduling policy that regulates the user peak rate. Our models take into account this policy and provides closed-form expressions giving all the required performance parameters for each traffic profile at a click speed. The model is compared with extensive simulations that show its accuracy and robustness

An Efficient Analytical Model for WiMAX Networks with Multiple Traffic Profiles

International audienceIn this paper, we present a simple and accurate analytical model for performance evaluation of WiMAX networks with multiple traffic profiles. This very promising access technology has been designed to support numerous kinds of applications having different traffic characteristics. The need for accurate and fast-computing tools is thus of primary importance to face complex dimensioning issues that integrate this traffic profile diversity. Our product-form queueing model provides closed-form expressions giving all the required performance parameters for each traffic profile at a click speed. The model is compared with extensive simulations that show its accuracy and robustness. Finally, the speed of our analytical tool allows us to carry on a preliminary performance study