Lotfi Kamoun

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.

Adaptive call admission control in 3GPP LTE networks

SUMMARY In this article, we propose new methods to reduce the handoff blocking probability in the 3rd Generation Partnership Project Long Term Evolution wireless networks. This reduction is based on an adaptive call admission control scheme that provides QoS guarantees and gives the priority of handoff call over new call in admission. The performance results of the proposed schemes are compared with other competing methods using simulation analysis. Simulation results show the major impact on the performance of the 3rd Generation Partnership Project Long Term Evolution network, which is reflected in increased resource utilization ratio to (99%) and in the ability in satisfying the requirements of QoS in terms of call blocking probability (less than 0.0628 for Voice over IP service) and dropping probability rate (less than 0.0558).Copyright

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.

Multi-criteria dynamic access selection in heterogeneous wireless networks

Service delivery in a heterogeneous wireless network environment requires the selection of an optimal access network. Indeed, the selection of a non-optimal network can result in undesirable effects such as higher costs in terms of new call blocking and handoff call dropping rates or poor service experience. Network selection in such an environment is influenced by several factors related to network conditions, application parameters, user preferences and terminal performances. This paper, first, describes a new architecture which allows a resource-efficient management that aims at selecting the “best-suited” network interface for each application. Second, it presents a comprehensive decision making process to rank candidate networks for service delivery to the application. The proposed scheme is based on a decision process using the TOPSIS method when solving the multi criteria analysis. The wireless networks in this model represent the alternatives, while the network and application parameters (bandwidth, Received Signal Strength, velocity support, load factor and power consumption cost) are considered as the criteria for determining the optimal network.

WBAN data scheduling and aggregation under WBAN/WLAN healthcare network

Nowadays, wireless body area networks (WBANs) become an emerging technology which has grown considerably. An increase in the deployment of devices on patients promotes researchers and application developers to focus on issues related to WBAN networks. Therefore, several studies have been done in this field by researchers. The IEEE 802.15.6 standard was proposed to satisfy all the requirements for WBANs communication. As sensed data in such type of networks, it should be transmitted in a reliable and QoS based way. A public-BAN is defined as a network of several personal-BANs. The centralized public-BAN consists of a static coordinator and several personal-BANs. The static coordinator is able to command a portable coordinator in order to control a personal-BAN and runs as an Internet Gateway. In this paper, we considered bridging communications between the IEEE 802.15.6-based WBANs and the IEEE 802.11e-based centralized public-BAN (WLAN). Especially, we proposed two new scheduling algorithms to satisfy QoS requirements in WBAN networks and to overcome the starvation mode of the packets without the highest priority. In order to perform this aim, we introduced the critical delay (CD) as a parameter to serve packets taking into account their priorities and classify them into an aggregated frame. The performance of our proposed schedulers is compared with Priority Queue scheduler (PQ) and Priority Queue Aggregation scheduler (PQA). Conducted simulations illustrate that our proposed schedulers performance overcomes the other schedulers in term of latency, throughput and dropped packets for emergency, general monitoring and controlled load traffics.

Investigation and performance analysis of MAC protocols for WBAN networks

Recently, interest in the Wireless Body Area Network (WBAN) for patient monitoring has grown significantly. Therefore, very interesting researches are concentrating on enhancing patient monitoring systems that require quality of services provisioning at different levels and especially in communication between WBAN nodes. Therefore, the conception of an efficient MAC (Medium Access Control) protocol is required to satisfy the stringent monitoring system requirements. In this context, investigations related to the most efficient and recent WBAN MAC protocols are carried out taking in consideration the requirements of WBAN MAC protocols, and the MAC proposals classification is presented in this paper. Furthermore, to illustrate the performance of the recently drafted IEEE 802.15.6 standard, IEEE 802.15.4 (Zigbee MAC) and TMAC protocols in different working conditions, we have elaborated different scenarios to simulate these protocols using CASTALIA framework and OMNET++ network simulator. Besides that, we have also computed the end-to-end delay (E2E) in the worst case for those protocols.

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.

Heterogeneous Wireless Networks: Configuration and Vertical Handoff Management

Vertical handoff is one of the most important issues for the next generation heterogeneous wireless networks. However, in many situations, unbeneficial vertical handoffs occur across intersystem heterogeneous networks cause network performance degradation. Therefore, we propose a novel configuration architecture that can be deployed in the next generation of wireless networks. Second, we propose a predictive and adaptive Vertical Handoff Decision Scheme that optimizes the handoff initiation time as well as selection of the most optimal network. The proposed vertical handoff decision algorithm considers the technology type as well as the Signal to Interference Ratio (SIR), the Mobile Station (MS) velocity, the user preferences, the applications requirements and the terminal capabilities as the most important factors to make vertical handoff decision. In order to minimize handoff costs, the proposed decision algorithm uses the dwell timer concept. The handoff costs are analyzed in terms of unnecessary and unbeneficial handoffs rate.The simulation results show that the reduction of unnecessary handoffs proposed in our vertical handoff decision scheme reduces the handoff blocking probability, the packets loss rate and the handoff overhead