Ultra wideband: applications, technology and future perspectives

Ultra Wide Band (UWB) wireless communications offers a radically different approach to wireless communication compared to conventional narrow band systems. Global interest in the technology is huge. This paper reports on the state of the art of UWB wireless technology and highlights key application areas, technological challenges, higher layer protocol issues, spectrum operating zones and future drivers. The majority of the discussion focuses on the state of the art of UWB technology as it is today and in the near future

Traffic placement policies for a multi-band network

Recently protocols were introduced that enable the integration of synchronous traffic (voice or video) and asynchronous traffic (data) and extend the size of local area networks without loss in speed or capacity. One of these is DRAMA, a multiband protocol based on broadband technology. It provides dynamic allocation of bandwidth among clusters of nodes in the total network. A number of traffic placement policies for such networks are proposed and evaluated. Metrics used for performance evaluation include average network access delay, degree of fairness of access among the nodes, and network throughput. The feasibility of the DRAMA protocol is established through simulation studies. DRAMA provides effective integration of synchronous and asychronous traffic due to its ability to separate traffic types. Under the suggested traffic placement policies, the DRAMA protocol is shown to handle diverse loads, mixes of traffic types, and numbers of nodes, as well as modifications to the network structure and momentary traffic overloads

A Review of UWB MAC Protocols

In this paper, we review several ultra-wideband (UWB) medium access control (MAC) protocols that have been proposed to date. This review then considers the possibility of developing an optimal MAC layer for high data rate UWB transmission systems that transmit very little power especially in application to mobile devices. MAC in UWB wireless networks is necessary to coordinate channel access among competing devices. Unique UWB characteristics offer great challenges and opportunities in effective UWB MAC design. We first present the background of UWB and the concept of MAC protocols for UWB. Secondly, we summarize four UWB MAC protocols that have been proposed by other researchers and finally, a conclusion with a view to the planned future work. The main contribution of this paper is that it presents a summarised version of several MAC protocols applicable to UWB systems. This will hopefully initiate further research and developments in UWB MAC protocol design

Implementation of a cognitive radio access system

Dissertação apresentada para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores, pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologi

CROSS-LAYER RESOURCE ALLOCATION SCHEME UNDER HETEROGENEOUS CONSTRAINTS FOR NEXT GENERATION HIGH RATE WPAN

International audienceIn the next generation wireless networks, the growing demand for new wireless applications is accompanied with high expectations for better quality of service (QoS) fulfillment especially for multimedia applications. Furthermore, the coexistence of future unlicensed users with existing licensed users is becoming a challenging task in next generation communication systems to overcome the underutilization of the spectrum. A QoS and interference aware resource allocation is thus of special interest in order to respond to the heterogeneous constraints of the next generation networks. In this work, we address the issue of resource allocation under heterogeneous constraints for unlicensed multi-band ultra-wideband (UWB) systems in the context of Future Home Networks, i.e. WPAN. The problem is first studied analytically using a heterogeneous constrained optimization problem formulation. After studying the characteristics of the optimal solution, we propose a low-complexity suboptimal algorithm based on a cross-layer approach that combines information provided by the PHY and MAC layers. While the PHY layer is responsible for providing the channel quality of the unlicensed UWB users as well as their interference power that they cause on licensed users, the MAC layer is responsible for classifying the unlicensed users using a two-class based approach that guarantees for multimedia services a high-priority level compared to other services. Combined in an efficient and simple way, the PHY and MAC information present the key elements of the aimed resource allocation. Simulation results demonstrate that the proposed scheme provides a good tradeoff between the QoS satisfaction of the unlicensed applications with hard QoS requirements and the limitation of the interference affecting the licensed users

Finding the Optimal MAC Protocol for Low-Power High Data Rate Ultra-Wideband (UWB) Networks

In this paper, we explore the possibility of designing an optimal medium access control (MAC) layer for high data rate ultra-wideband (UWB) transmission systems that transmit very little power especially in mobile devices. MAC in UWB wireless networks is necessary to coordinate channel access among competing devices. The unique UWB characteristics offer great challenges and opportunities in effective UWB MAC design. We first study the background of UWB and available MAC protocols that have been used in UWB. Secondly, we analyse the power consumption for UWB in mobile devices based on competing short-range wireless technologies such as Bluetooth and Wi-Fi as references. Finally we present the key issue that will be considered in the design of an optimal MAC layer that will fully exploit UWB potential as a low-power, high data rate, short range wireless transmission system