Motorola (France)

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper addresses the problem of source and relay transmit covariance optimization on the Gaussian MIMO relay channel with full channel state information (CSI), i.e., assuming perfect knowledge of all channels. For full-duplex relaying, we show that the cut-set bound on capacity can be computed as the solution of a convex problem, thus providing a tighter bound than previously published. For time division duplex (TDD) relaying, both upper and lower bounds on capacity are derived, and the transmit covariance matrices are optimized for decode-and-forward (DF) strategies with either partial or full decoding at the relay. A generic procedure is introduced to formulate these problems into a standard convex form, and to solve them efficiently. Suboptimum precoders are also proposed which have a specific matrix structure that either leads to a closed-form expression or at least reduces the dimension of the optimization problem. Practical aspects related to transmit power constraints and CSI availability are then discussed. Finally, simulations in a cellular downlink scenario show that the partial DF strategy can achieve a rate very close to capacity for realistic values of the source to relay SNR, and that the rate loss due to suboptimum precoder structures remains small for typical antenna configurations. </para>

Over the past decade or so, the wireless industry has undergone many significant changes. Radio systems have moved toward forming heterogeneous wireless networks: collaborations of multiple radio access networks, which in some cases operate different radio access technologies, such as second- and third-generation cellular RATs, IEEE 802.x wireless standards, and so on. On the other hand, multimode reconfigurable user devices with the ability to choose among various supported RATs have become a reality, and devices and networks with dynamic spectrum access capabilities, allowing real-time sharing of spectrum resource usage among different systems, are expected to be a part of the future radio eco-space. As a result of these changes, there is a need to develop a standard that addresses the requirements and leverages the opportunities posed by such a versatile radio environment. To this end, IEEE 1900.4 aims to standardize the overall system architecture and information exchange between the network and mobile devices, which will allow these elements to optimally choose from available radio resources. In other words, the standard facilitates the distributed dynamic optimization of the usage of spectrum offered by the heterogeneous wireless network, relying on a collaborative information exchange between networks and mobile devices, thereby acting as a common means to improve overall composite capacity and quality of service for the served networks. This article provides a snapshot of IEEE P1900.4 in its current form, covering the scope and purpose of the standard, reference use cases for which the standard is applicable, its system and functional architectures, and finally, the information model for its main interfaces.

This chapter focuses on the following aspects of the mobile user experience: • Multimodality: How to make the best use of available devices, those that the user carries with her (such as a cell phone) or those that become available while she moves (such as an audio car kit); and for each of those devices, how to make the best use of the various modalities (such as sound, video and text) they offer. • Personalisation: How to ensure that the applications offered to the user are tailored to her specific needs and her specific situation. This chapter introduces a multimodality framework that allows an application to easily provide content to the user on the most suitable device and using the most suitable modality, and presents a personalisation framework that manages the user's personal information and helps applications to adapt themselves to the user needs.

Regulation will experience enormous changes in the near future resulting in seamless connectivity by bluring spectrum borders. A promising approach in this context is dynamic spectrum allocation which leads to a more flexible access to spectral resources by employing intelligent radio devices called cognitive radios. This paper is concerned with bio-inspired approaches that exploit distribution in multi-radio environments where many users have to share a finite resource harmoniously. Three applications of bio-inspired techniques are described. The first one deals with the detection of spectrum holes and the second one describes resource allocation in orthogonal frequency division multiple access based systems. The third one is concerned with distributed resource auctioning.

In a beyond 3G context, many wireless technologies can cooperate or interoperate, within dynamic and reconfigurable networks. In this changing radio environment, the challenge for the cognitive terminal is to be able to connect to the relevant network, according to several criteria. E2R has developed concepts and solutions for a Cognitive Pilot Channel (CPC) to bring enough information to the terminals for network selection when terminals are proceeding either initial connection or handoff. This paper focuses on the network selection strategy according to the information which could be brought by CPC and also some information of user preference stored in terminals previously. In the latter part, a network selection algorithm is presented, which can both improve the system performance and satisfy users well.

A converged broadcast and telecommunication service platform is presented that is able to create, deliver, and manage interactive, multimedia content and services for consumption on three different terminal types. The motivations of service providers for designing converged interactive multimedia services, which are crafted for their individual requirements, are investigated. The overall design of the system is presented with particular emphasis placed on the operational features of each of the sub-systems, the flows of media and metadata through the sub-systems and the formats and protocols required for inter-communication between them. The key features of tools required for creating converged interactive multimedia content for a range of different end-user terminal types are examined. Finally possible enhancements to this system are discussed. This study is of particular interest to those organizations currently conducting trials and commercial launches of DVB-H services because it provides them with an insight of the various additional functions required in the service provisioning platforms to provide fully interactive services to a range of different mobile terminal types

We claim a new approach for UWB antennas taking advantages from the classical and the fractal techniques by applying a log spiral transformation to a fractal design. Stricto senso, this antenna loose its mathematical fractal properties but keeps the physical advantages of a real fractal pattern. A concrete realization of this concept on a twisted Sierpinsky carpet is presented in this paper. To cancel potential additional resonance deserving UWB pulse system, we also propose to use different iterations of the pattern or different fractal initiator for each arm of this antenna. Based upon the simulation of a dipolar twisted Sierpinski carpet, several advantages related to this concept have been emphasized and are detailed here.

UWB pulse based modulation systems are intrinsically sensitive to time jitter. On one side, sensitivity to timing accuracy increases with the bandwidth. On another side, increasing the bandwidth allows better performance in multipath channel context and with a diversity combining receiver. For a given desynchronization, there exists an optimal bandwidth which provides the best trade-off between diversity combining and jitter impact in term of average bit error rate. This contribution shows how these two effects are linked in a binary PPM with Poisson arriving multipath channel models like those proposed in the IEEE 802.15.3a task group