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Details of Grant 

EPSRC Reference: EP/D506824/1
Title: Improving Spectrum Utilization by Real-time Propagation Forecasting
Principal Investigator: Watson, Dr RJ
Other Investigators:
Evans, Dr AN
Researcher Co-Investigators:
Project Partners:
STFC Laboratories (Grouped)
Department: Electronic and Electrical Engineering
Organisation: University of Bath
Scheme: Standard Research (Pre-FEC)
Starts: 12 December 2005 Ends: 11 December 2008 Value (£): 184,022
EPSRC Research Topic Classifications:
Digital Signal Processing Modelling & simul. of IT sys.
RF & Microwave Technology
EPSRC Industrial Sector Classifications:
Communications
Related Grants:
Panel History:  
Summary on Grant Application Form
Radio communication systems provide a multi-billion pound input to the UK economy. At very high frequencies, such as the those used for transmitting satellite television using dish antennas, radio systems are greatly affected by the weather For example, when it rains the signal that comes from the satellite in space become smaller when it passes through cloud and rain. This reduction in signal strength is called attenuation. Because it doesn't always rain and isn't always cloudy the attenuation, like the weather, is very variable.The conventional way in which designers of communications systems ensure that radio link works is to make use statistics. Firstly, they measure the attenuation over a long period of time (at least a year) and then calculate the percentage of time that a particular value of attenuation is exceeded. Turning this problem around we can also determine up to what value of attenuation occurs for a particular percentage of time. For example, for 99.9% of the time during the year, and for a particular frequency, we can determine a fixed value that the actual value of attenuation will be less than. This fixed value of attenuation is called the fade margin. If we now incorporate this fade margin into the design, the systen will work 99.9% of the time. The fraction of time that the system works is called its availability.The problem with this sort of worst-case design is that for some fraction of time the system is over-specified. For example, if its is a dry and cloud-free day we might not need as much transmitter power to make the system work as we would if it was raining really hard. The novel approach that we propose in this project is to use the same tools that weather forecasters use to predict the weather to predict on a continuous basis how big the fade margin needs to be such that the radio system will still just work.Just as the weather forecasters sometimes don't get the weather quite right, we might not always get the radio propagatioi prediction right. We need to know what is going to happen to the radio system if we use this technique and we get the weather forecast wrong. To do this we need to be able to simulate the sort of things that might go wrong with the weather forecast. For example, what happens if it rains harder than we said it was going to? Does the radio system still work?Even when using directional dish antennas, signals still go in unwanted directions and can cause interference with other links. This is especially true if we are trying to increase the power on a link to combat the effects of rain attenuation for example. Advance knowledge of all of the likely fades on all of the links in the network can help manage these problems.
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Organisation Website: http://www.bath.ac.uk