LOOKING BEFORE WE LEAP!Propagation Science Experts Measure the Real World before Communications Projects are Launched.
The Canadian public owns a valuable resource that they cannot see, hear, smell or touch, but is worth billions of dollars to our economy ... That resource is the electromagnetic spectrum.
The uses for the spectrum are ubiquitous: radio and television transmissions, cell phones, ham radio, police radar and radios, wireless Internet, remote garage door openers, and the list goes on and on.
Data transfer over radio link is well understood and very useful, but before we can launch any new service we first must allocate a frequency band where this service can operate effectively and without undue interference from or to other services.
That being said, all frequencies were not created equal. David Rogers, program manager at CRC's Radio Propagation Laboratory explains:
"As new services come online there is a shortage of spectrum, particularly at lower frequencies. One of the reasons that lower frequencies are attractive is that the technology is relatively inexpensive.
For example, cellular telephones operate at fairly low frequencies and the equipment used is fairly inexpensive. However, there is not enough room in that part of the spectrum for all of the new applications that are coming online. Broadband access, for instance, is just one application that may require service providers to move to higher frequencies, to take advantage of the greater bandwidths allocated in higher bands.
In this higher frequency portion of the spectrum, propagation characteristics are less well characterized. It is our responsibility to try to understand the physics of any transmission using this spectrum, including power requirements; the effects of precipitation; signal blockage and scatter from buildings and other structures, and the potential for interference problems with other services. Many millions of dollars may be at stake when launching new services. Our expertise reduces the risks of poor performance and interference with existing services before these investments are made.
New concepts are constantly being brought forward, and they have to be evaluated. For instance, we are currently looking at MIMO, or multiple-input/multiple-output systems. This is a new concept for which the achievable performance is currently unknown. So we could not make a frequency allocation and demand a certain capacity utilization from a service provider, if we don’t know if it can be met.
One other reason that CRC propagation expertise is so important to Canada is that we are such a large and somewhat sparsely populated country. We need to provide reliable communications to remote areas and to the military in the far north, for example. Canada's climate and environments are extremely diverse and this makes a difference to communication performance and the effects must be understood. Provision of service in a mountainous area can be very difficult due to blockage and diffraction by the hills and so on and so forth. If you want to provide reliable services in areas where there can be huge variation in local conditions, you need to be very sophisticated in your understanding of propagation issues."
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