Lecture Series in Mobile Telecommunications and Networks (1583KB)

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To the edge of chaos? The complexity and the promise of a technology and service-neutral future Professor Linda Doyle Associate Professor Department of Electronic & Electrical Engineering Trinity College, University of Dublin I am honoured and also quite humbled to be here, because the lecture I shall give touches on a wide range of topics and I am very much aware of your huge expertise in the individual products. This is a great opportunity to be here and discuss some of the ideas with you. I want to talk about spectrum and spectrum management. Spectrum is the life-blood of any communication system and it is very dear to my heart. I will go through a few of the ideas about spectrum management with you today. I will start by talking about how spectrum management has been questioned in recent years and what is currently happening in the topic, before I move on to some of the ideas for the future of spectrum. You will recognise this as the sinking Titantic. The loss of the Titanic was a major catalyst in what became what we know as spectrum management today. When the Titanic sank, boats that were much nearer when the Carpathia came to help did not actually receive the distress signal from the Titanic, so chaotic were things at the time. This acted as a catalyst to encourage governments, particularly in the United States and around the world to think of a spectrum differently, and to organise how spectrum should be managed. It was no longer a right to transmit, but you actually had to be granted that right by the authorities. So this was very much a catalyst in how things began. This diagram represents where we are today and how the vast majority of spectrum management takes place. What happens currently is that some international body, like the ITU, broadly defines what services and frequencies Frequency Band 1 : Frequency Band 2 : Frequency Band 3 : Frequency Band 4 : Frequency Band 5 : Mobile Services Broadcast Services Fixed Services Mobile Operate A Mobile Operate B should be used for what purposes, and Site licensed & managed by the regulator Site block licensed & managed by the operators what technologies should be used to deliver that. Then, on the more Source: http://www.ofcom.org.uk/consult/condocs/sur/specturm/ national level, that picture is refined and then a spectrum is assigned, in various different ways, to those who want to use it. So the way it is currently assigned tends to be based on first-come, first-served, right up to much more complex options, where a companies like Vodafone and O2 bid for 3G spectrum and everybody is probably familiar with some of the options they have had in recent years. Unused - Guard Band Unused - Guard Band Unused - Guard Band People very often refer to this approach as an administrative one, or you often hear the term ‘command and control’. This emphasises the fact that this is a quite centralised approach, where someone on-high decides what will happen to the spectrum – what services will be used in those particular bands, and then people react accordingly and do what they are told. In the US, you often hear people talk about that ‘Mother, may I?’ approach, where you have to ask permission to do things and you do not take the initiative. Unused - Guard Band The Royal Academy of Engineering 23
ComReg Collection - Start 16/Apr/2007. 18:02:30. Stop: 18/Apr2007, 12:09:00 ComReg Collection - Start 16/Apr/2007. 18:02:30. Stop: 18/Apr2007, 12:09:00 Source: Shared Specturm Company (http://www.sharedspecturm.com/) NYC Measurements 31- Aug-2004 15:15:41 NYC Measurements 31- Aug-2004 15:46:09 What is very attractive about the approach is that it allows us to manage interference very well. Regulators are able to model and understand how communications are likely to interfere with each other and tailor licences accordingly. So, you can put power into licences, and you can also stipulate where guidelines are, so that that does not interfere with the rest of it, so life is quite organised and it is very attractive from that perspective. The downside of this is that many people feel that this system is one, and first of all that it is not very responsive to new technologies and changes. Secondly, you are forcing regulators and authorities to pick winners. There are some fantastic examples of where winners have been picked really well. If you look at what happens with GSM, and at how harmonisation across Europe occurred and how the GSM network and service has developed, that is fantastic. However, there are other examples – for example in the EU – where we are all directed to put spectrum aside for applied specifically for urban paging technology, and that never came into being and the spectrum sat there, idle. So the picking of winners is a kind of ‘wise man’ approach, and it is part and parcel of the vast majority of spectrum management that we have known to date. This need to pick winners and the slow responsiveness to new technology is something that people are seriously beginning to question. Another thing that people question the arises is the question of spectrum scarcity. I do not know whether anyone here has ever looked at those very colourful spectrum allocation charts, where there is no space for anything else – the spectrum looks ‘full’. This has been hugely challenged in the past, and part of that challenge has resulted in these kinds of measurements. If you just concentrate on the middle part of this slide, the part that shows frequency usage, you can see what is going on. They are a bunch of frequencies, and this is time, and the blue means a low signal, while the red means a really busy, high level of signal. You can see that there is a good deal of spectrum that is completely unused all the time, or spectrum that is perhaps unused at night time – the time here corresponds to the night time. So people are saying, ‘Okay, there is the spectrum around. I want spectrum – I have a new idea and want to innovate, but I can’t get any, but these measurements are showing me that free spectrum exists. This is a similar measurement, taken by this company called Source: Shared Specturm Company (http://www.sharedspecturm.com/) the Shared Spectrum Company in 2004. The measurements on the previous slide were also taken by this company. The reason why I have included these is because, very interestingly, these were taken in New York City during the Republican Convention at the time. A whole range of measurements were taken and not just one set of conclusions here. Despite the fact that it is a really busy city and a really busy time, there is still evidence in very many places that the spectrum is not being used extensively. 24 The Royal Academy of Engineering
Page 1 and 2: Lecture Series in Mobile Telecommun
Page 3 and 4: Foreword This compilation brings to
Page 5 and 6: From wireless networks to sensor ne
Page 7 and 8: From wireless networks to sensor ne
Page 9 and 10: As far as the routing of packets is
Page 11 and 12: easons. In the internet, one never
Page 13 and 14: Implementation with laser pointers,
Page 15 and 16: here of laptops, and all these lapt
Page 17 and 18: adds a great deal of discrete compl
Page 19 and 20: Questions & Answers Mike Walker: Th
Page 21 and 22: Human beings will also evolve and w
Page 23: Welcome and introduction Professor
Page 27 and 28: evidence that people give in favour
Page 29 and 30: chunks of spectrum where you are in
Page 31 and 32: As an aside, I was reading a few of
Page 33 and 34: Of course, it is not just one mask,
Page 35 and 36: I apologise for hopping between top
Page 37 and 38: Questions & Answers Michael Walker:
Page 39 and 40: Nobody - believe you me, it came ou
Page 41 and 42: The second aspect of my comment is
Page 43 and 44: want to call it - that sits there a
Page 45 and 46: From plain old Telephony to flawles
Page 47 and 48: From plain old Telephony to flawles
Page 49 and 50: You can see that there is much room
Page 51 and 52: 1024, we transmit 10 bits, so to sp
Page 53 and 54: Bandwidth extension with hidden sid
Page 55 and 56: 4 Vision: ambience audio communicat
Page 57 and 58: Questions & Answers Michael Walker:
Page 59 and 60: I said five years ago and what I he
Page 61 and 62: them and perhaps leave out some of

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