Tackling the Problem of Satellite Interference
by Martin Coleman
London, September 3, 2010--As technology moves on, so do the demands on our media infrastructure. In the world of satellite that is as true as everywhere. Satellites are being used for a whole plethora of activity, from broadcasting to powering navigation across the globe. This increased demand has a negative effect however on the feed to the satellite in the form of radio frequency interference, meaning, for broadcasters in particular, a less than perfect television viewing experience.
Using ID on any service is nothing unusual but surprisingly this has not been applied to today’s satellite transmissions. The Carrier ID initiative, being led by the Satellite Users Interference Reduction Group (SUIRG), will significantly reduce the time taken to track and correct day-to-day interference. Many of the problems stem from the fact that no-one knows who is causing the interference in the first place. If two transmitted carriers attempt to use the same frequency, who is right? The problem can be simple or complex. ID tries to eliminate the obvious.
Having an ID assigned to each transmission makes sense of course, but fast resolution is a must and making it easy to determine the cause of the problem and speedier resolution, in turn, will lead to less interference and therefore less downtime for the broadcaster or other affected services.
As with any initiative, the challenge has always been getting support and involvement from supply companies involved in the process of satellite transmission and the broadcaster or service provider. SUIRG has put a great deal of effort into fostering these relations where in late 2009, three working groups covering Video, Data and VSAT were created. On the Video front this has been easier to implement as specifications and mandates had been setup some years before. Taking Video transmission as the example, we are now at a point where encoder manufacturers are preparing and in many cases, have achieved the goal of making Carrier ID available on all video encoders for the single transmit chain scenario. Effort is currently being directed towards the inclusion of multiplexed transmission streams by using the uplink modulator to embed that same ID. In addition, discussions continue with major broadcasters in all main regions with specific input from the Americas, Asia and Europe looking at cost effective ways to integrate ID in such services in this more complex service structure. This has led to looking at the multiplexer itself as another way to embed ID, something that had initially been avoided, but following discussion, is now being revisited.
Being in Control
Of course, better than reduced interference, would be no interference at all.I have personally always been a great advocate of automation or simplifying the operation of any transmission system to avoid both equipment and human error. Using proper, well defined automation leads to transmission schedules being met, errors reduced and therefore interference avoided.
The most vulnerable systems are those of the SNG vehicle and Flyaway terminal. It is all too easy for operational errors to occur on a typical SNG vehicle, for example. However, by providing automated step-by-step task management of the operations carried out by the transmission equipment of that vehicle, those errors can be drastically reduced, if not eradicated. Less mistakes leads to efficient operation and a significant reduction in interference. Add to this proper scheduling, then planning of transmission services is simplified and conflicts avoided.
In addition, with good infrastructure, the broadcast control center should be part of that automated management and include any ground station transmission centers they may have. In other words, integrate your automation. In addition to ID and automation, there is a real need to integrate more tools within any terminal’s functionality. These tools could range from simple task of logging of events and operations, to transmissions times (thus automating billing) and eventual sophistication allowing any terminal to self-monitor and take appropriate action to avoid such incidents as dual illumination interference (a very common problem) and report this quickly and simply to operations personnel.
Staying in Control
In order for SUIRG to be successful in its bid to minimize satellite interference, broadcasters and satellite users across the globe need to be on board with these initiatives. There are many ways in which we can achieve this aim, but it needs to be driven by the industry as a whole.
Martin Coleman is Managing Director of Colem and Chairman of the SUIRG Video Working Group, he can be reached at firstname.lastname@example.org