Lamia Chaari

PHY/MAC Enhancements and QoS Mechanisms for Very High Throughput WLANs: A Survey

Wireless local area networking has experienced tremendous growth in the last years with the proliferation of IEEE 802.11 devices in order to improve wireless technology. The first generation of high throughput networks known as IEEE 802.11n was developed in 2009 to reach 130 Mbps. Furthermore, to enhance the throughput, two new amendments for IEEE 802.11 are under developments which are IEEE 802.11ad and IEEE 802.11ac. The first one aims to reach 1Gbps with supporting multi-user access techniques. The second amendment aims to enable up to 7Gbp with the possibility of transmitting in the 60GHz band that provides the opportunity for much wider band channels. Another WLAN is already finalized called IEEE 802.11aa in the goal to provide a reliable multicast transport for video streaming. In this survey, we examine the different PHY and MAC enhancements introduced by all these WLAN specifications. Particularly, we focus on the characteristics of each amendment as well as the main MAC mechanisms that lead to improve the network performance. Based on the fact that all recent MAC mechanisms aim to increase QoS guarantee for real time multimedia applications, we have studied different schemes and mechanisms that provide QoS satisfaction for real time multimedia flows transport over WLANs. Namely, we investigate the scheduling mechanisms, the call admission control algorithms, and the anticipated MAC enhancement which are proposed for WLANs networks to support real time applications with QoS satisfaction.

A Comprehensive Overview of Wireless Body Area Networks WBAN

In recent years, the wireless body area network WBAN has emerged as a new technology for e-healthcare applications. The WBANs promise to revolutionize health monitoring. However, this technology remains in the first stages and much research is underway. Designers of such systems face a number of challenging tasks, as they need to address conflicting requirements. This includes managing the network, the data, while maximizing the autonomy of each network node. Reducing the consumption of a node, the management of network resources and security insurance are therefore major challenges. This paper presents a survey of body area networks including the WBANs challenges and -architecture, the most important body sensor devices, as well as sensor board hardware and platforms. Further, various applications of WBANs in the medical field are discussed, as well as wireless communications standards and technologies. The newest researches related to WBANs at physical and MAC layers are presented. Finally the paper identifies data security and privacy in WBANs as well as open research issues.

Study of medium access mechanisms under IEEE 802.15.6 standard

Wireless body area network (WBAN) is paving the way for the deployment of a variety of medical and non-medical applications. This class of networks has emerged in the recent years and much of the research in the area of body area networks has focused on issues related to ultra low-power processing and communication, lightweight wireless sensor nodes in order to control the human body functions and healthcare monitoring systems. The task Group 6 of IEEE 802.15.6 is formed to address specific needs of body area networks. It defines a medium access protocol control (MAC) layer that supports three physical layers namely NarrowBand (NB), Ultra WideBand (UWB), and Human Body Communications (HBC) layers. In this paper, we present major MAC requirements of WBAN, we overview various proposed MAC protocols for WBAN and we highlight the MAC protocol concepts of IEEE 802.15.6.

A Priority based Cross Layer Routing Protocol for healthcare applications

Wireless body area networks (WBANs) represent one of the most promising approaches for improving the quality of life, allowing remote patient monitoring and other healthcare applications. Data dissemination and medium access in a WBAN are critical issues that impact the network reliability, the efficiency and the total energy consumed by the network. In this paper, we propose a Priority-based Cross Layer Routing Protocol (PCLRP) along with a Priority Cross Layer Medium Access Channel protocol (PCLMAC) for healthcare applications.PCLRP combined with PCLMAC ensures reliable traffic dissemination and customized channel access for intra- and inter-body communications. Simulation results show that the proposed protocol achieves customized quality of services and outperforms state of the art existing protocols in terms of power consumption, packet delivery ratio and delay.

Upcoming WLANs MAC access mechanisms: An overview

This paper gives an overview of the recent medium access control (MAC) mechanisms which are rising today. We focus on the already existing IEEE 802.11 and IEEE 802.11e MAC mechanisms, as well as those which are under development such as IEEE 802.11ac, IEEE 802.11ad, and IEEE 802.11aa. We describe the 802.11ac access mechanisms which support the multi-user access techniques in the form of sharing the transmit opportunity TXOP period. For the 802.11ad, we explain protocols that enable up to 7 Gigabit. We detail 802.11aa access mechanisms that guarantee more reliable multicast transport for video streaming.

Multi-Attribute Decision Making Handover Algorithm for Wireless Body Area Networks

In this paper, we tackle the Wireless Body area Network (WBAN) handover issue where a mobile patient has to select at any time the best access technology according to multiple criteria. We particularly focus on the decision schemes and investigate the Multi-Attribute Decision Making (MADM) methods. The fundamental objective of the MADM methods is to determine among a finite set of alternatives the optimal one. Therefore, we propose a Multi-Attribute Decision Making Handover Algorithm (MADMHA) which helps patients mobile terminal to dynamically select the best network by providing a ranking order between the list of available candidates. It is a seamless handover approach that guarantees continuous connectivity with respect to the QoS requirements of the WBAN generated traffic types, network history and user preference. Simulation results prove the efficiency of our proposed approach versus the Received Signal Strength Indicator (RSSI) and Data Rate (DR) based handover approaches. Indeed, compared to these latters, MADMHA significantly reduces the packet overhead and the number of handover, while limiting the packet loss ratio.

A comprehensive survey on Carrier Ethernet Congestion Management mechanism

In the literature, congestion control schemes have been broadly studied. Nevertheless, this subject needs to be reviewed in the context of Carrier Ethernet. Congestion happens when the capacity cannot cover the resource demands. Nowadays, users are witnessing the networks saturation because of the expanding demands for bandwidth. The addressed issue is not only how to avoid congestion but also how to use all available capacity without overuse it or underuse it. To deal with congestion, link level algorithms drop or mark packets with increasing probability as buffer congestion increases. The most common solution is based on the transport layer algorithms to adjust the resources transmission rate by using these dropped or marked packets. Carrier Ethernet defined by layer two uses new proposals specified by the 802.1Qau standards committee in order to handle congestion problems. This paper surveys and studies different properties of Carrier Ethernet congestion control schemes. This paper also draws a parallel between the different schemes and point out the advantage and disadvantage of each one. Then, this paper presents a taxonomy of the Carrier Ethernet congestion control mechanism and correlate it with existing taxonomies.

A Comprehensive Survey on WiMAX Scheduling Approaches

The institute of Electrical and Electronics IEEE 802.16 standard is a real revolution in wireless metropolitan area networks (wireless MANs) that enables high-speed access to data, video and voice services. The IEEE 802.16 is mainly aimed at providing broadband wireless access (BWA). Thus, it complements existing last mile wired networks such as cable modem and xDSL. Its main advantage is fast deployment which results in cost saving.

QoS Concepts and Architecture Over Wireless Body Area Networks for Healthcare Applications

Wireless Body Area Networks WBANs applications have emerged as one of the most recent research areas of wireless sensor networks. Lots of research is improving QoS factors in sensor networks. However, QoS requirements vary from application to application, WBAN applications are very sensitive, and QoS issues in WBAN need major concern and focus. This paper outlines the WBANs QoS requirements and factors and reviews with emphasis on their strengths some medium access mechanisms that response to some QoS challenges. Moreover, the authors have defined and specified a QWBAN MAC protocol that can allow the integration of QoS architecture over WBAN. A set of QoS modules such as admission control CAC, bandwidth allocation and scheduling are discussed. Besides that, an integrated QoS architecture is suggested for WBAN to support healthcare applications.

An overview of mobility management over IEEE802.16e

Providing diverse broadband services economically every time, even to mobile subscribers will be a major challenge for the telecommunication community. IEEE 802.16 networks are going to provide broadband wireless access as a fixed wireless broadband solution. However, the IEEE 802.16e as an amendment to 802.16d which expands the standard to allow mobile subscriber station. As handover is an important aspect of mobile wireless communications, we have studied and analyzed concepts, functionalities and keys aspects to provide mobility over IEEE802.16e. This paper looks particularly at the advanced features introduced by the IEEE802.16e standard for mobility in WiMax systems in order to prove that the enhanced IEEE 802.16e system has the capability to fulfill the requirements regarding the mobility management of future telecommunication systems.