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Can spectrum provide the answer?


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Script from presentation at 'Every European Digital': The Challenge of Bridging the Broadband Gap, in Brussels, May 2011
Presenter: Richard Womersley of Helios
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Can spectrum provide the answer?

  1. 1. Every European Digital: The Challenge of Bridgingthe Broadband Gap Brussels, 31 May 2011Can spectrum provide the answer?Presentation by Richard Womersley, HeliosWe all know that spectrum is an increasingly hot topic. It is a limited resourcefacing rapidly growing demand. Over the past 20 year that I have been involved inspectrum management, introducing new wireless services has gone from being atechnology first, spectrum second approach, to being a spectrum first, technologysecond approach, recognising the higher value and importance of spectrum intechnology implementation.The question I have been asked to address is "Can spectrum provide the answer?"But in order to be able to decide whether spectrum can provide the answer, wefirst need to know what the question is!I think the question we are trying to answer is "Can spectrum be used to achievebroadband for all using terrestrial wireless broadband networks?" CommissionerKroes said that opening up spectrum reduces the number of sites needed. This isunquestionably true, but "Can spectrum provide the answer?" My answer is a firmno.Let me explain.Wireless broadband networks, whether fixed or mobile, have to trade off threeeconomic and technical factors: low cost, high coverage and high capacity (that isthe ability to provide high speed connections to large numbers of users).A network can achieve any two of these, but not all three. For example, it ispossible to have a network with high coverage at low cost but not one which alsoprovides high capacity. So a rural network providing connections for remote usersis possible at low cost, but it will not provide high speed connections to every user.Equally it is possible to have a high capacity network at low cost, but it will notcover large areas. Such a network might be found in a densely populated citycentre.So these are the trade-offs that all operators have to juggle in order to deliver acommercially viable service. But what are the challenges they face and what arethe tools they can used to deal with them?According to various sources (such as the much cited Cisco white paper), demandfor data on wireless networks is approximately doubling every year. Some networkoperators are already claiming that some of their 3G cells are at full to capacity atthe busiest times of the day. Others are already offloading data onto WiFi wherehotspots are available to reduce the load on their networks. 1
  2. 2. Wireless network operators have therefore to decide how to tackle this increasingdemand, whilst at the same time trying to roll-out additional coverage to providebroadband to new customers and to innovate in service provision in order to remaincompetitive.To grow their network, operators have access to three fundamental choices: Firstlythey can use more efficient technology, moving from 2G to 3G or 3G to 4G.Secondly they could roll-out additional infrastructure using new sites to providemore coverage or capacity. Or alternatively they could use more spectrum.First let’s consider technology. A recent study for Ofcom has demonstrated thatthe next generation mobile broadband technology (LTE) is just over 3 times morespectrally efficient than current 3G (UMTS) networks. This represents just over 18months growth based on current data traffic expectations. Does new technologyhelp solve the cost, capacity, coverage problem? Slightly. But to implement thenew technology on an existing site is costly, and whilst this might improvecapacity, it does little for coverage. Further, the costs of using new technology areexacerbated by the need to replace user equipment as well as networkinfrastructure. Thus there is a growth in capacity but a growth in cost and thetrade off between cost, coverage and capacity remains.What about additional infrastructure? Any new sites will obviously incur new costs.This is acutely the case for sites in remote areas where the economic andenvironmental cost of developing sites, including supplying power and providing abackhaul connection into the rest of the network, are particularly high. New sitesdo provide additional coverage and can provide additional capacity but this comesat a high cost and so does nothing make juggling cost, coverage and capacity anyeasier.And so to spectrum. Wireless operators in most European countries share around500 MHz of spectrum between them. The digital dividend will add another 60 MHzto this pot. This is 12% more, and would deal with about 6 weeks growth in data.Even if the amount of spectrum available were doubled, a move which is beingproposed by several European regulators, this would only provide space for a 12months growth in data. Worse still, to use spectrum in a new band requires newinfrastructure to be installed, and new user equipment, much the same as using anew technology does, and thus the juggling act continues.Lets re-cap: • Any commercially viable terrestrial wireless broadband network has to trade off high coverage and high capacity against low cost. • Data is estimated to be doubling each year. • New technology is approximately three times more efficient, accounting for 18 months growth of data, but this requires new (and expensive) re-fits of sites. 2
  3. 3. • The digital dividend will only provide spectrum to deal with 6 weeks growth of data. • Even doubling the current amount of spectrum only deals with 12 months growth of data. • Using new technology or new spectrum also requires new user equipment and new network infrastructure.To the question of "Can spectrum provide the answer?" the fundamental fact is thatthere is simply not enough spectrum to deal with the growth in data. Nor willtechnology offer a solution which deals with long-term growth. The only solutionfor operators is to roll-out new sites both in inner cities and slowly pushing out intomore scarcely populated areas. And this is expensive to the extent that publicsubsidy may be necessary to make such sites commercially viable.This does not mean that objective to provide broadband for every European is notfeasible, nor that it requires public subsidy. We should not forget that there areother technologies which are much better suited to providing cost-effectivebroadband coverage, together with a host of other services, in remote areas, inparticular satellite. Satellite does not suffer the same coverage issues thatterrestrial networks do, one satellite could cover the whole of Europe, but still hasto trade off capacity and cost. What is therefore essential is the use of a mix oftechnologies, with each playing to their strengths: Fibre in cities, terrestrialwireless in the suburbs and satellite in rural areas.If the question we are trying to answer is can spectrum be used to achievebroadband for all using satellite broadband networks? my answer would still remaina no for many of the same reasons I have already given. But as with terrestrialnetworks, satellite spectrum (such as Ka-Band) remains an important input todelivering commercially viable services.Taking spectrum away from one broadband technology to give it to another (suchas is being proposed for the 3.4 to 3.8 GHz band) is like diverting water suppliesfrom agricultural to domestic or industrial use. It may provide short-term benefit,but may have devastating long-term economic and environmental implications.In conclusion, "Can spectrum provide the answer?" No. But as Commissioner Kroessaid, “we have to use all the tools available to us”, and I strongly agree. Allwireless technologies, whether terrestrial or satellite need sufficient, secureaccess to spectrum to allow them to play their roles in achieving Europesbroadband ambitions.For more information, contact Richard Womersleyrichard.womersley@askhelios.comTel: +44 1252 451 3