While nature does not operate in blocks, allocations or in convenient-sized chunks, radio spectrum management can be achieved once the notion of frequencies and frequency blocks can be formulated and spectrum can be discussed in meaningful terms. Without meaningful terms, spectrum trading cannot be achieved.
The foundations of spectrum engineering is modelling – establishing the scope of the use of spectrum without affecting the users of frequency blocks either side. Modelling identifies the parameters of the spectrum capability; spectrum engineering makes it possible to achieve that.
Spectrum engineering means working with adjacent spectrum blocks and hardware companies. All radio equipment clearly needs to be compatible with the frequencies it uses and fit for purpose. It is vital that both the sponsors of a new network and the manufacturers work in unison. In its two decades of business, ATDI has been an effective conduit between network operators and hardware companies; the company has a track record in advising both sides and helping them reach mutually beneficial solutions.
The company’s expertise extends in an international remit. While an island nation, radio signals from the UK have the power to affect systems in other countries (and vice-versa) so it is vital there is liaison and coordination – not least with all the relevant spectrum regulators – if every user of spectrum is to achieve a good service.
Spectrum engineering encompasses all the practical elements of making a block of frequencies do a job without affecting neighbouring users. Getting that job done on time and on budget, and to the satisfaction of all affected parties, is ATDI’s core competence.
The closer two aircraft are, the more danger there is for all involved. Never are planes in greater proximity or concentration than on the ground so effective coordination is essential if they are to taxi around airports without problems. Radio is used to keep traffic controllers and pilots in contact and in sync – but every radio network on an airport has the potential to interfere with other vital systems such as radar. Precise planning and modelling is required if all safety systems are to work effectively.
An international airport was undergoing reconstruction and redevelopment. Its management needed to ensure aircraft on the ground would be in constant contact with controllers during and after all the building works were complete. Specifically, the airport operator needed to know if a new, second transmitter was required to achieve this. As with any commercial operation in the world, the airport did not want to spend money if it did not have to but, if the only option was a second transmitter, the new network could not cause interference to existing systems.
ATDI constructed a 3D model of the terrain and the buildings that made up the redeveloped airport terminal. Once this was done, proposed radio sites were placed within the modelling environment and configured with the relevant equipment. Then, a link budget was built that reflected actual working of the communications between air traffic controllers and pilots. Finally, coverage predictions were completed using a suitable propagation model. From this data, the airport management could establish whether a second transmitter was needed. Keeping aircraft safe
ATDI: the planning power that airports trust
Wind farms are sprouting up across the UK on land and on sea – and each one of them has the potential to interfere with radar systems used by air traffic controllers. The Civil Aviation Authority (CAA), which is responsible for the safe transit of aircraft through British airspace, advises all wind farm developers to get specialist help in determining the turbines’ potential effect before they are built.
The CAA recognises that it takes an expert to plan and model the effect of wind turbines on radiocommunications systems, and in particular radars, accurately, and it falls to companies like ATDI to ensure that air traffic control systems work effectively in the proximity of a wind farm. The potential problem is that the speed at which the tips of the turbines rotate can confuse a radar system and make it give an inaccurate reading for the position of an aircraft in flight.
ATDI has planned and modelled the potential problems from wind farms for a number of developers and has given advice on mitigation techniques. Importantly, the company has also facilitated communications between wind farm companies and air traffic controllers. This discussion has created solutions before problems occur, and that has saved money for developers and ensured the safety of air passengers.
ATDI: making the turbines turn safely
Knowledge is power. Radio spectrum regulators, faced with the legal requirement to make the most efficient use of resources, all face the same issue of identifying and quantifying the factors that make a country’s communications work; in tandem with this, they must also ensure that all elements work efficiently and without interfering with each other. To achieve that, they require detailed and accurate knowledge.
A European regulator needed to know the location, purpose and power of each base station in its country. In addition, because of the nation’s strong tradition of open government, it was important for the regulator to be able to publish this information for public scrutiny and comment. ATDI’s task was to find a way of collating data from the competing companies using the spectrum, then to establish how to integrate that information into the regulator’s existing systems and, finally, to present the figures as a workable database which could be accessed, searched and updated via the current spectrum management system.
ATDI engineers analysed the process of importing external operator data into the database management system of ATDI’s ICS manager software tool. The procedures created utilised the new Harmonised Computer Method (HCM) functionality component within ICS manager. Thus, on receipt of information about the base stations from operators, the regulator was able to import,access and amend data as required. The end result was a database incorporating every tower and its function across the country. This enabled the regulator to ensure appropriate provision of radiocommunications services across the nation while assuring the Green lobby that power was not being wasted nor were the population being subjected to unnecessarily emissions.
ATDI: controlling data and putting it to work
Radio planning and modelling has taken on a new role in saving money for architects and developers. Consumer demand for wireless broadband and good quality television reception is a factor in the siting of tall buildings; internet users and viewers of terrestrial and satellite TV channels are likely to protest if a new construction diminishes the quality of their services – and councils are legally obliged to take those views into consideration when deciding whether to grant planning permission. To avoid time-consuming rejected planning applications and expensive appeals, architects and developers are increasingly using radio planning and modelling to assess and address the potential impact of their project. Knowing what effect the building would have gives its constructors the opportunity to modify plans; and if plans do not need to be changed, radio modelling gives developers the evidence they need to reassure councillors and likely opponents to the scheme that problems will be minimal or negligible.
The developers of a tall building in a European capital city wanted to know the potential impact of the building on broadcast services while the building’s design was still fluid.
ATDI’s radio network planning tools can predict the specific radio shadow – that is, the area of degraded or lost reception – of a building and assess its impact. So, a 3D environmental model of the affected area using terrain, buildings and vegetation data was used. Once computed, these results defined the radio shadow which was then presented as an overlay on a topographic map and aerial photograph; this gave a clear visual representation of any impact. ATDI’s work identified that the new building did have an effect on radiocommunications, although that effect was limited to broadcast and public cellular services. This information was invaluable to developers finalising the building’s design.
ATDI: saving developers time and money
Everybody is cautious with money, and the bigger the sum, the more cautious people are. So, when a spectrum regulator offers frequencies for sale with price tag in millions, everybody involved wants an extremely precise definition of what is being sold and what it will do.
A European regulator was preparing for an auction of spectrum to operators of Long Term Evolution (LTE) mobile networks and asked ATDI to provide the planning and modelling that would identify potential of the frequencies, areas where there might be issues and what strategies and tactics were available to reduce or remove those issues. All parties were acutely conscious that in this mountainous country, the population was concentrated in a few cities and that the frequencies for sale were close to those used by television broadcasters; significant interference to either the television or LTE signals would not be acceptable, nor would wholesale exclusion of the rural population from services.
To reduce the interference between television and LTE networks, several mitigation techniques were investigated in a sample area around the capital city. One of the most efficient mitigation techniques was found to be to limit the interfering LTE base stations to only vertical polarisation; this is based on the fact that, with a few minor exceptions, the country’s digital television network is horizontally polarised. ATDI also proposed that while network designs were being completed, LTE operators should consider the interference potential to the television networks and suggest mitigation techniques they could deploy to overcome the effects, including filtering. In addition, the company advocated a feasibility study to assess the re-assignment of spectrum of affected areas away from channels 58 to 60; the study would also look at the effect of not using these channels in highly populated areas.
ATDI: smoothing the path of radio auction