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

Cross-Layer Resource Allocation for MB-OFDM UWB Systems

ISBN 978-953-3076461-0International audienc

DIFFERENTIATED MULTIUSER RESOURCE ALLOCATION SCHEME FOR MULTI-BAND UWB SYSTEMS

ISBN: 978-1-4244-3695-8International audienceThis paper considers the dynamic resource allocation in a multiuser context taking into account the quality of service (QoS) requirements for the high-rate ultra-wideband (UWB) systems. The aim of this paper is twofold. First, we exploit the effective SINR method in the multi-band WiMedia solution proposed for UWB systems. This method is based on the exploitation of the characteristics of multiple sub-carrier SINRs in order to provide the channel state information needed for the multiuser sub-band allocation. Second, using the effective SINR as a channel metric, we derive a multiuser convex optimization problem to find the optimal allocation for all users while differentiating between two traffic classes: hard-QoS and soft-QoS. A low-complexity cross-layer allocation algorithm is also proposed. The cross-layer solution is a combination of two simple processes, one working at the PHY level and the other at the MAC level. Simulation results show that the proposed cross-layer solution performance is close to that of the optimal solution and it outperforms the single-user WiMedia solution in the hard-QoS users cas

A critical analysis of research potential, challenges and future directives in industrial wireless sensor networks

In recent years, Industrial Wireless Sensor Networks (IWSNs) have emerged as an important research theme with applications spanning a wide range of industries including automation, monitoring, process control, feedback systems and automotive. Wide scope of IWSNs applications ranging from small production units, large oil and gas industries to nuclear fission control, enables a fast-paced research in this field. Though IWSNs offer advantages of low cost, flexibility, scalability, self-healing, easy deployment and reformation, yet they pose certain limitations on available potential and introduce challenges on multiple fronts due to their susceptibility to highly complex and uncertain industrial environments. In this paper a detailed discussion on design objectives, challenges and solutions, for IWSNs, are presented. A careful evaluation of industrial systems, deadlines and possible hazards in industrial atmosphere are discussed. The paper also presents a thorough review of the existing standards and industrial protocols and gives a critical evaluation of potential of these standards and protocols along with a detailed discussion on available hardware platforms, specific industrial energy harvesting techniques and their capabilities. The paper lists main service providers for IWSNs solutions and gives insight of future trends and research gaps in the field of IWSNs

Ultra-Wideband Secure Communications and Direct RF Sampling Transceivers

Larger wireless device bandwidth results in new capabilities in terms of higher data rates and security. The 5G evolution is focus on exploiting larger bandwidths for higher though-puts. Interference and co-existence issues can also be addressed by the larger bandwidth in the 5G and 6G evolution. This dissertation introduces of a novel Ultra-wideband (UWB) Code Division Multiple Access (CDMA) technique to exploit the largest bandwidth available in the upcoming wireless connectivity scenarios. The dissertation addresses interference immunity, secure communication at the physical layer and longer distance communication due to increased receiver sensitivity. The dissertation presents the design, workflow, simulations, hardware prototypes and experimental measurements to demonstrate the benefits of wideband Code-Division-Multiple-Access. Specifically, a description of each of the hardware and software stages is presented along with simulations of different scenarios using a test-bench and open-field measurements. The measurements provided experimental validation carried out to demonstrate the interference mitigation capabilities. In addition, Direct RF sampling techniques are employed to handle the larger bandwidth and avoid analog components. Additionally, a transmit and receive chain is designed and implemented at 28 GHz to provide a proof-of-concept for future 5G applications. The proposed wideband transceiver is also used to demonstrate higher accuracy direction finding, as much as 10 times improvement

Optical techniques for broadband in-building networks

Optical fibres, which can easily handle any bandwidth demand, have been rolled out to more than 32 million consumer’s homes and professional buildings worldwide up to 2010. The basic technological and economical challenges of fibre-to-the-home (FTTH) has been solved. The current FTTH technology can now providing baseband Gbit Ethernet and high definition TV services to the gates of homes. Thus, the bottleneck for delivery of broadband services to the end users is shifting from the access network to the in-building network. In the meantime, the need for high-capacity transmission between devices inside the building, e.g. between desktop PC and data services, are also rapidly increase. How to bring high bandwidth to the mobile terminals such as laptops, PDAs or cell phones as well as to the fixed terminals such as desktop PCs and HDTV equipment in an all-in-one network infrastructure is a challenge we are facing. Building on the flexibility of the wireless access networks and the latent vast bandwidth of a fibre infrastructure, radio-over-fibre (RoF) techniques have been proposed as a cost-effective solution to the future integrated broadband services in in-building networks. This thesis investigates techniques to deliver high data rate wireless services via in-building networks: high capacity RoF links employing optical frequency multiplication (OFM) and sub-carrier multiplexing (SCM) techniques, with single- or multi-carrier signal formats. The orthogonal frequency division multiplexing (OFDM) format is investigated for the RoF transmission system, particularly with regard to the optical system nonlinearity. For low-cost short-range optical backbone networks, RoF transmission over large-core diameter plastic optical fibre (POF) links has been studied, including the transmission of the WiMedia-compliant multiband OFDM UWB signal over bandwidth-limited large-core POF as well as a full-duplex bi-directional UWB transmission over POF. In order to improve the functionalities for delivery of wireless services of in-building networks, techniques to introduce flexibility into the network architecture and to create dynamic capacity allocation have been investigated. By employing optical switching techniques based on optical semiconductor amplifiers (SOA), an optically routed RoF system has been studied. The dynamic capacity allocation is addressed by investigating one-dimensional and two-dimensional routing using electrical SCM and optical wavelengths. In addition, next to RoF networking, this thesis explores techniques for wired delivery of baseband high capacity services over POF links by employing a multi-level signal modulation format, in particular discrete multi-tone (DMT) modulation. Transmission of 10 Gbit/s data over 1 mm core diameter PMMA POF links is demonstrated, as a competitor to more expensive fibre solutions such as silica single and multimode fibre. A record transmission rate of more than 40 Gbit/s is presented for POF whose core diameter is comparable with silica multimode fibre. Finally, from the network perspective, the convergence of wired and wireless multi-standard services into a single fibre-based infrastructure has been studied. Techniques have been designed and demonstrated for in-building networks, which can convey both high capacity baseband services and broadband radio frequency (RF) services over a POF backbone link. The multi-standard RoF signals carry different wireless services at different radio frequencies and with different bandwidths, including WiFi, WiMax, UMTS and UWB. System setups to carry them together over the same multimode optical fibre based network have been designed and experimentally shown. All the concepts, designs and system experiments presented in this thesis underline the strong potential of multimode (silica and plastic) optical fibre techniques for the delivery of broadband services to wired and wireless devices in in-building networks, in order to extend to the end user the benefits of the broadband FTTH networks which are being installed and deployed worldwide

UWB MAC Design Constraints and Considerations

In this paper, we consider the possibility of developing an optimal medium access control (MAC)layer for high data rate ultra-wideband (UWB) transmission systems that transmit minimal power. MAC in UWB wireless networks is required 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 explore the constraints on UWB MAC design. Finally we present the considerations that need to be made in designing an optimal UWB MAC protocol