Written on 10:33 AM by ooe
Allocations made for narrowband wireless local loop applications vary from country to country but in most cases they are in the 2 to 4 GHz band. Individual operators have been granted spectrum allocations of approximately 10 to 50 MHz within these bands, which is relatively small. There is increasing interest in using these frequencies for mid-band systems offering data services as well as voice. The advantage over higher frequencies is that these systems can work over greater distances and use less sophisticated and hence less expensive components. However, there is inherently less spectrum available and it is in demand for future wide area mobile systems.
Broadband systems require more spectrum and the allocations that have been made, or are being considered, lie within the 10 to 40 GHz band. indicates the major allocations in the US and Europe. Shown are both issued and proposed licences, with the UK shown separately from Europe to illustrate that even within one region there are still national differences. It can be seen that a number of past licences issued for fixed wireless access in the UK are under consideration for reallocation, due to lack of use.
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Written on 10:33 AM by ooe
A common licence condition for block allocations specifies whether or not spectrum trading is permitted. If it is, the winning operator may subsequently transfer their licence to another party for instance if they wish to sell it or merge their licence holdings with those of another operator. If trading is prohibited, an operator is not at liberty to sell their licence and if they no longer require it, it must be returned to the government for resale.
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Written on 10:33 AM by ooe
An alternative method of awarding block licences is commonly known as a ‘beauty contest’. In most cases, an annual fee is charged for the licences, but this is an administrative charge, much lower than the likely auction price. The award is based not on which operator is willing to pay the most, but rather the operator who undertakes to make best use of the spectrum.
In a similar way to the minimum permitted performance licence conditions often imposed on auction winning operators, the beauty contest attempts to ensure that the government's original objectives in issuing the spectrum are met. While an auction process limits itself to specifying a minimum set of desirable parameters that the resultant network must exhibit, the beauty contest award decision is given to the operator whose proposed network offers the most desirable features. Exactly how these desirability criteria are judged will again depend on the original objectives.
One obvious flaw with this process is that an operator could over-promise in an attempt to secure a licence. For this reason, the promises usually form the basis of the winner's licence conditions. Additionally it is common for a detailed business plan to be required which shows achievable forecasts for revenue and expenditure.
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Written on 10:32 AM by ooe
Block spectrum allocations are often awarded using a competitive auction. Holders of such licences can use the spectrum wherever and as often as they like, within a given country or region. Such awards usually last for a set number of years, with the issuing authority then claiming back the spectrum for reissue or an alternative use.
There have been many successful auctions for FWA spectrum around the world with considerable income being generated, for instance the 1998 US LMDS auctions (spectrum in the 28–31 GHz range) raised $600 million. However, the UK 28 GHz auction held in 2000 illustrates the risk to governments of using this process – 26 of the 42 licences offered failed to attract any bids, leaving large parts of the UK without any broadband FWA operators to compete with existing access providers.
Other risks occur depending on the government's original motivation in offering the spectrum for FWA usage. In many cases the objective is to increase competition in the access market by using the potentially low cost of entry offered by wireless networks compared to wired networks. One possibility is that the licence winner will ‘cherry pick’, only offering service in the highest profit areas. This can mean that only the most densely populated business districts will obtain the benefit of increased access competition. Alternatively, the spectrum might be used for infrastructure connections, such as point-to-point backhaul connections within the operator's network, rather than for its intended application in access networks. Outcomes such as these can be guarded against by introducing licence conditions such as minimum coverage areas that must be achieved within a given time and strict definitions on the permitted use of the spectrum.
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Written on 10:32 AM by ooe
This type of spectrum licence charging tends to be applied to point-to-point systems, where dedicated spectrum is required for each customer connection. The operator must apply for the spectrum required for each radio link and the licence obtained is only valid for that frequency in that particular location. Generally, if the link is removed, the spectrum licence must be handed back to the issuing government. Charging may have temporal, capacity, usage and geographic elements.
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Written on 10:32 AM by ooe
Some spectrum can be used without payment to the government that owns it. Some such spectrum still requires the user to obtain a licence prior to use and some is set aside for use without any permissions at all, provided certain technical constraints are met. The main example of the latter are the internationally agreed ISM (industrial, scientific and medical) bands, this spectrum often being known as ‘licence-exempt’. Whilst the technical parameters vary by country, the aim is the same – to make spectrum available that may be used on an ad hoc basis without need for prior permission. Example applications include microwave ovens and industrial heaters, wireless LANs and remote control units. Another emerging use of these bands in many countries is for commercial fixed wireless access networks, often focused on delivering data services and based on existing wireless LAN technology.
Within the UK there is an unusual constraint on these bands which limits their licence-exempt use to ‘private self-provided communications’ in effect precluding their use for commercial access networks without a licence. Thus far the government has only issued one commercial use licence per region within the UK.
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Written on 10:32 AM by ooe
All fixed wireless access systems require a portion of the radio spectrum in which to operate. In almost all cases, a licence to use this spectrum must be purchased from the appropriate government agency before the system can be operated or even planned. The size of the radio spectrum is in theory infinite, extending from zero hertz through progressively high frequencies to light, x-rays and beyond. In practice only a very limited part of this spectrum is usable for commercial access systems. Demand for these frequencies is huge and growing all the time with competition to fixed terrestrial access systems coming from uses such as satellite communications, radio astronomy, industrial applications, emergency services, television broadcasting, telemetry, mobile communications, military and medical applications.
The large and ever changing appetite for such a scarce resource leads to a requirement for careful management on national, continental and global fronts, which in turn limits the amount of spectrum available for fixed wireless access use at any point in time. Suitable parts of the radio spectrum, or bands, are usually made available by a national government when agreement is reached with all other previous or potential users of the spectrum and there is judged to be significant interest from operators.
Would-be fixed wireless access operators therefore face the difficult situation where their ability to deploy a network is dependent on being able to obtain a licence for suitable spectrum from the local government, who may or may not make such licences available at some point in future. This makes spectrum an absolutely essential ingredient in any planning or operation of wireless networks.
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