Rebollo-Monedero, D.; Bartoli, A.; Hernández-Serrano, J.; Forne, J.; Soriano, M. European transactions on telecommunications Vol. 25, num. 1, p. 94-108 DOI: 10.1002/ett.2708 Data de publicació: 2014-01-01 Article en revista
A key aspect in the design of smart cities is, undoubtedly, a plan for the efficient management of utilities, enabled by technologies such as those entailing smart metering of the residential consumption of electricity, water or gas. While one cannot object to the appealing advantages of smart metering, the privacy risks posed by the submission of frequent, data-rich measurements cannot simply remain overlooked. The objective of this paper is to provide a general perspective on the contrasting issues of privacy and efficient utility management, by surveying the main requirements and tools, and by establishing exploitable connections. Copyright (c) 2013 John Wiley & Sons, Ltd.
In this contribution, the optimised deployment of both spectrum and energy resources scarcely available in the mobile multiple access systems has been analysed, with special attention to the impact of the filter design on the energy efficiency (EE) of code division multiple access networks. Putting into perspective two conflicting metrics, namely throughput maximisation and power consumption minimisation, the distributed EE utility function is formulated. We also show that the best EE versus spectral efficiency trade-off is achievable when each node allocates exactly the power necessary to attain the maximum EE. In order to demonstrate the validity of our analysis, a low-complexity energy-spectral-efficient algorithm based on distributed instantaneous signal-to-interference-plus-noise ratio level is developed, and the impact of single and multi-user detection filters on the EE–spectral efficiency trade-off is extensively analysed by numerical simulation.
This work studies the improvement in service coverage obtained by three different approaches to combining
two triangulation (terrestrial and satellite) location methods for cellular networks in an urban environment.
The paper assumes that the terrestrial cellular network uses enhanced observed time difference (E-OTD) in
2G or observed time difference of arrival (OTDOA) in 3G, while the satellite GNSS uses the assisted global
positioning system (A-GPS), but the analysis can be easily generalised to other triangulation methods. A
straightforward analytical model is presented to evaluate the service coverage resulting from each of the
three approaches. The model is fed with actual coverage figures, gathered from test measurements carried
out in Paris (France) for several urban scenarios. Numerical results show that the three approaches lead to
improvements in all the tested scenarios, and that the improvement obtained by the increasing complexity of
the fusion approach depends highly on the coverage of each individual method and on the joint probability
function of individual performances
We introduce and evaluate a novel reflection routing protocol to reduce burst losses in emerging optical burst switching (OBS) networks. The proposed solution selects the reflection neighbour based on current link state information. To keep pace with OBS traffic dynamics, we propose link state information to be propagated downstream in the burst control packet. As the result, accurate state information of the return links coming from each adjacent neighbour can be maintained, thus improving reflection neighbour selection. Simulation results show up to 98% improvement against classic reflection routing, also outperforming standard deflection routing (DR) especially for medium-sized burst lengths.
The multiple-access interference (MAI) is one of
the major factors threatening the performance of multiuser
systems. Transmit beamforming is a powerful strategy to increase the system capacity and mitigate interference. Traditional zeroforcing transmit beamforming (ZFBF) is an effective means to remarkably suppress MAI if the downlink channel is precisely known. However, it is very difficult to get exact information on the actual channel in realistic scenarios. In this paper, we present an approach to achieve orthogonal transmit beamforming (OTBF), only in virtue of statistical information of the downlink channel by using semidefinite programming tools. Different criteria are considered to solve the same problem by satisfying specific constraints between the total transmission power and the quality of service (QoS) requirements of individual users. Furthermore, robust designs for the presented approaches are also analyzed.
Simulation results show the effectiveness and the robustness of these strategies
Bostica, B.; Burzio, M.; Callegati, F.; Casoni, M.; Rafaelli, C.; Masip Vilalta, Joan; Solé-Pareta, J. European transactions on telecommunications Vol. 10, num. 3, p. 18-30 Data de publicació: 1999-05 Article en revista