processing signals drawn from various sources in the network, the last point in the communicational chain - the destination node - is able to extract and restore the original message. Paradoxically, it is by virtue of their difference – the distortion element which differentiates the signals – that they can be contrasted, and the integrity of the original communication salvaged. “Some of our recent work has compared our proposals to current ‘multi- hop’ techniques, and found them to be performatively superior, in terms of throughput,” Lévêque attests. Demand, too, no longer becomes a
hinderance in this model, but a strength – since each new transmitter and receiving unit which joins the network strengthens it. By working within small ‘clusters’, and then in larger, joint combinations of clusters, the network is able to ‘scale up’ to meet the
own communications systems,” enthuses the informational specialist. These meticulous predictions also formed
a core part of the investigations into wireless, laying essential groundwork for the hierarchical co-operation model. “If you scrutinise separate nodes in different places, and the signal transmissions relayed between them, you’ll witness attenuation; fading of the signal,” elaborates Lévêque. “To anticipate how well communications might operate, you need to consider the channel matrix resulting from the interactions between the pairs of nodes within the network. You must study the statistical properties of these matrices to understand a system’s capabilities, which has prompted several lines of enquiry within our project.” Next on the agenda is an examination of possible delays between transmitters and receivers, which must be
Project Information AT A GLANCE
Project Title: New random matrix models for wireless communications
Project Objective: Self-organized wireless communication networks offer the promise to answer the increasing wireless traffic demand in coming years. The aim of the present project is to assess the feasibility of such networks on a large scale. This requires the study of statistical properties of the matrices modeling the interactions between the nodes in the network.
Project Duration and Timing: 3 years
Project Funding: Swiss National Science Foundation
Project Partners: EPFL, Stanford
Main Contact:
needs of users, and operate at long distances. “These
‘hierarchical co-operation
schemes’, which involve all of the nodes in the network, should help to achieve optimal capacity,” relates Lévêque. “However, the chips and technology to facilitate it are not yet available. First, we need to find partners to collaborate with, and help us achieve this. But there is a widespread belief that this type of system will ultimately enhance communications – within science, and industry”. Whilst a future implementation could
assist developed nations in better managing the deluge of bits and bytes clogging their bandwidths, it will also support those with fewer resources. “Because there is no need for a fixed structure, this application could function in territories with few base stations, helping residents to establish their
www.projectsmagazine.eu.com
mitigated to ensure that bit-rates remain unhindered. Left unchecked, these can, in a digital environment, result in irritatingly faltering video streams – or
a vexing
imitation of the lengthy pauses and elliptical dialogues experienced during long-distance international phone calls. “We
don’t have a test-bed as yet”
confesses Lévêque, who is keen to engage with partners who are forging the cutting- edge technology which may realise his vision. “The strategy we propose is theoretic, and thus there are many practical issues to resolve before it can be implemented. Nonetheless, we are confident in and keen to realise our concepts, through implementing a programme which fosters their transformative potential.” It’s a promising remedy to an endemic problem for the
telecoms sector that, the scientist warns, will become exacerbated until viable solutions are phased in. “The number of devices continues to explode. It’s a natural evolution – which will continue to stretch current requirements, until we can surpass them,” he predicts. “Increasing demands for data-intensive applications like video streaming means that this question will not go away – and that the industry must face it.”
★ 51
Olivier Lévêque Research scientist at the Swiss Federal Institute of Technology - Lausanne, since 2001. With a background in physics and mathematics, his main research interests are in information theory and its application to the design of future communication networks.
Contact: Tel: +41 21 693 81 12 Email:
olivier.leveque@epfl.ch Web:
http://ipg.epefl.ch/~leveque/
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132