New contention resolution schemes for WiMAX

Abstract—The use of Broadband Wireless Access (BWA) technology is increasing due to the use of Internet and multimedia applications with strict requirements of end–to–end delay and jitter, through wireless devices. The IEEE 802.16 standard, which defines the physical (PHY) and the medium access control (MAC) layers, is one of the BWA standards. Its MAC layer is centralized basis, where the Base Station (BS) is responsible for assigning the needed bandwidth for each Subscriber Station (SS), which requests bandwidth competing between all of them. The standard defines a contention resolution process to resolve the potential occurrence of collisions during the requesting process. In this paper, we propose to modify the contention resolution process to improve the network performance, including end–to–end delay and throughput

A Scalable QoS Scheduling Architecture For WiMAX Multi-Hop Relay Networks.

WiMAX Mobile Multi-hop Relay (MMR) network has been introduced to increase the capacity and extend the coverage area of a single WiMAX Base Station (BS) by the use of a Relay Station (RS)

An architecture for IEEE 802.16 MAC scheduler design

Copyright © 2007 IEEEThe scheduling algorithm for IEEE 802.16 broadband wireless access system has been left open in the standard. In this paper, we consider three criteria that we have identified as important criteria for an 802.16 scheduler: Service Type differentiation, dynamic sub-frame partition and Subscriber Station differentiation. We investigate the scheduler design from a general perspective, based on these three criteria

Channel Aware Uplink Scheduler for a Mobile Subscriber Station of IEEE 802.16e

The scheduling part of the IEEE 802.16 (WiMAX) standards is kept as an open issue to provide differentiation among equipment manufacturers and operators. The uplink scheduling is very significant and more complex compared to downlink scheduling. Uplink scheduling is divided into two parts; one is scheduling the resources among many users from a base station (BS) and the other is sharing the resources among its services in a single user. BS uplink scheduling has been given more attention compared to subscriber station (SS) uplink scheduling. SS scheduler plays a significant role in providing the quality of service (QoS) among its services. The channel status awareness is vital in designing the SS scheduler as the channel conditions vary for a mobile user. This work proposes a scheduling algorithm for SS, which utilizes the channel information and queue length variation for the reallocation of received aggregated bandwidth grant to optimize the QoS parameters. The performance of the proposed algorithm is studied by conducting simulations using QualNet 5.0.2 simulation tool. Simulation results demonstrate the effectiveness of the proposed algorithm to improve the QoS

Non-Cooperative Game Theory Approach for Cognitive Cooperative Communication in WBAN

To increase the Quality of Service (QoS) of wireless body area network, we need an effective data-rate delivering method, which capably forwarding the data over several path. For this reason, we proposed a non-cooperative game approach, based on utilizing a pricing-based spectrum leasing mechanism to transmit the data over several path based on non-cooperative game theory. The parameter price c is together determined by WBAN sensor and D2D users. Then, all selected D2D users used optimized powers that can fulfil the need of the WBSN users. Numerical results show the proposed approach improves the utility of WBSN users and their throughput

QoS em WIMAX – Análise e avaliação de módulos para simulação com o ns-2

Mestrado em Engenharia Electrotécnica e de ComputadoresA tecnologia WIMAX (Worldwide Interoperability for Microwave Access), definida na norma IEEE 802.16, tem recebido grande destaque no que diz respeito a tecnologias de acesso sem fios em banda larga (BWA – Broadband Wireless Access). O WIMAX oferece acessos sem fios com características específicas, tal como, o suporte de qualidade de serviço (QoS) na camada MAC. Estando esta tecnologia ainda em evolução, a implementação de soluções é, normalmente, precedida por fases de estudos e de simulações de forma a encontrar soluções que viabilizem o seu sucesso. O simulador ns-2 (Network Simulator) é uma das ferramentas mais utilizadas para a simulação de redes computacionais. Esta ferramenta permite a simulação de redes com e sem fios, bem como de vários protocolos utilizados na internet. No entanto, o ns-2 ainda não permite simular a tecnologia WIMAX, levando os investigadores a proporem módulos que, integrados na ferramenta ns-2, possibilitem a simulação desta tecnologia. Este trabalho apresenta um estudo do WIMAX efectuando-se uma comparação de três módulos implementados para a simulação deste protocolo no ns-2. A norma IEEE 802.16 não especifica como deve ser controlado o escalonamento de QoS, pelo que o objectivo deste trabalho centrou-se na comparação dos módulos disponíveis, avaliando-se quais os que apresentam uma abordagem mais rigorosa ao nível do escalonamento de QoS. O primeiro módulo simulado foi desenvolvido pela Networks & Distributed Systems Laboratory (NDSL) tendo a capacidade de efectuar o controlo de QoS na camada MAC enquanto que, o segundo módulo, implementado pelo National Institute of Standards and Technology, NIST, não tem essa competência. Recentemente foi disponibilizado mais um módulo capaz de garantir a qualidade de serviço, implementado pela Universidade Estadual de Campinas (UNICAMP). Os resultados obtidos nas simulações efectuadas neste trabalho tentam comparar os módulos, verificando se estes são capazes de assegurar as especificações da norma 802.16, para todas as classes de serviços e em diferentes cenários de simulação.The WIMAX (Worldwide Interoperability for Microwave Access) technology, defined on IEEE 802.16 standard, has received great attention in the area of Broadband Wireless Access (BWA) technology. WIMAX provides wireless accesses with specific characteristics, such as, the support for Quality of Service (QoS) in the MAC Layer. Since this technology is still evolving, implementations are usually preceded by the study and the simulation steps, towards the definition of a successful solution. The Network Simulator (ns-2) is a popular tool for simulation of computer networks. This tool provides substantial support for simulation of Internet protocols over wired and wireless networks. Nevertheless, the ns-2 still does not provide facilities to simulate the WiMAX technology, leading the researchers to propose WIMAX modules, which are integrated with ns-2 in order to enable the simulation of this technology. This thesis presents a study of WIMAX, which provides a comparison of three WIMAX modules developed for simulating this protocol with ns-2. The IEEE 802.16 standard does not specify how should be controlled the scheduling mechanisms for QoS, therefore the main purpose of this study was to compare the available modules and to assess which one implements the most rigorous approach of QoS scheduling. The first module was developed by Networks & Distributed Systems Laboratory (NDSL), and has the ability to manage QoS in the MAC layer, while a second module developed by the National Institute of Standards and Technology (NIST) has no such competence. Recently, a new module was released by the State University of Campinas (UNICAMP) that also implements the quality of service mechanisms. The results of the simulations described in this thesis aim to compare the performance of modules and to check if they are able to ensure the specifications of the 802.16 standard, for all classes of services in different simulation scenarios

The Media Layers of the OSI (Open Systems Interconnection) Reference Model: A Tutorial

The Media Layers of the open systems interconnection (OSI) reference model convert bits to packets. It is a very important aspect of network communication and consists of various networking protocols. At the lowest level the physical layer deals with Media, Signal and Binary Transmission of Bits. Then there is the Data Link layer which deals with media access control (MAC) and logical link control (LLC) Physical Addressing of Frames, for example Ethernet. Finally, there is the Network layer which deals with Path Determination and IP Logical addressing of Packets. This article gives a review of these Media Layers and will contribute to adding knowledge for a networking novice while consolidating concepts for an experienced professional or academic