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New Efforts to Mitigate Satellite Interference

By | March 1, 2010

      The success enjoyed by the commercial satellite sector over recent decades comes as no surprise to the engineers, technicians and managers who have been contributing to its remarkable growth by providing customers with accurate and reliable services around the globe. Yet, to the uninitiated, satellites can still be seen as daunting technology, perhaps because of the extreme environment in which they operate. Naturally, nothing could be further away from the truth. The continuous effort in the development of state-of-the-art technology in both the space and Earth segments, and the adoption of built-in redundancy at almost every level, make sure that satellite networks today support services that enjoy unmatched reliability.

      In our experience, episodes of signals from unauthorized carriers and of cross-polarization make up 70 percent to 75 percent of radio frequency interference cases plaguing satellite operations. — Guillemin, Intelsat

      But while satellite reliability and use have grown in parallel, there is a rise in the incidents of radio frequency interference reported each year. “Incidents of interference occur constantly all over the world. Large satellite fleets can experience up to 100 interference events a month,” says Thierry Guillemin, Intelsat’s CTO. “A majority of incidents are attributed to faulty ground terminals installation practices, uplink errors and poor equipment maintenance regimes,” he says. And Intelsat’s experience, of course, is far from being unique among satellite operators

      While the severity of these events varies greatly, ranging from slight signal degradation to full outage, it is not difficult to understand why they can create problems to satellite operators and their customers. Radio interference disrupts data transmissions and degrades television signals being delivered via satellite, hindering both the smooth delivery of services and their quality. As a consequence, radio interference has a negative effect on business for satellite operators and their customers. While difficult to assess with precision given the erratic nature of the problem, the economic consequences of radio frequency interference are believed to be severe. According to analysis carried by the Satellite Users Interference Reduction Group (SUIRG), a global organization dedicated to combating this problem, satellite operators can suffer from hundreds of thousands to millions of dollars per year in lost revenue and additional manpower required to investigate episodes of radio frequency interference.

      “Ultimately, radio frequency interference disrupts television signals, data transmissions and other customer services, hindering business growth,” says Guillemin. “This affects us as well, of course. As operators, we also have to troubleshoot and try to fix them as soon as possible.”


      Many Causes

      Radio frequency interference has many causes. Among the most important ones are the use of faulty equipment, often due to poor manufacturing quality or unmet performance specifications, and lack of industry standards and guidelines on equipment use. However, it is operational issues that make up the most widespread cause of radio interference. Typically, these include the reduction of orbital spacing between satellites and the unauthorized use of satellite space segment by carriers. The field experience of satellite operators such as Intelsat seems to confirm this.

      “In our experience, episodes of signals from unauthorized carriers and of cross-polarization make up 70 percent to 75 percent of radio frequency interference cases plaguing satellite operations,” says Guillemin. “To this number, you should add a 15 percent to 20 percent of cases caused by adjacent satellite interference.”

      Issues such as interference from unauthorized carriers and cross-polarization should be considered only as manifestations of the problem. The root cause of the majority of these episodes can be traced to the human factor, and the vast majority is unintentional — i.e., someone, somewhere making a mistake with the equipment, says Robert Ames, president and CEO of SUIRG. The human factor can take the form of lack of or insufficient training for staff, decrease in knowledgeable workforce due to staff turnover, as well as poor equipment installation and lack of routine maintenance.

      Collective Solution

      Great emphasis is being placed on developing technical tools with a corrective capability that monitor systems. “State-of-the-art proactive tools monitor critical systems, removing the element of human error that manual monitoring can potentially introduce,” says Paul Khayat, global connectivity services marketing manager at Schlumberger. “These tools utilize complex algorithms to identify problems within seconds, allowing tickets to be immediately and correctly graded according to the severity and classification of the issue. This ensures the most appropriate engineer assignments.” Often, the tools’ intelligence also allows for genuine proactive fault anticipation where potential fault scenarios can then be notified before any traffic loss.

      In addition, at the internal level, satellite operators and other market players along the value chain are focusing on making sure that staff members receive adequate training and that proper processes are in place to guarantee the correct use of satellite equipment. Yet, while important, these measures appear to be insufficient in tackling the problem when taken at a company level, as Richard Wolf, ABC’s senior vice president of telecommunications and network origination services, says. “At ABC, we work with Intelsat-optimized equipment and properly trained staff. However, we also rely on several third-party providers. The reality is that we can control ourselves, but we cannot control all of our suppliers,” he says.

      Clearly, an industry-wide initiative is needed to guarantee quality across the board and along the satellite value chain, and consensus has emerged among industry players that the sharing of information among operators to identify and characterise the issue of interference is a clear priority. “Gathering information and establishing metrics on the issue is essential in this process,” says Wolf. “It’s only after defining a clear picture of the issue that we as an industry can identify the problem areas and define a strategy to target them.”

      Operators and customers always have shared information on interference, though in the past this happened in an informal way. However, through the institution of a Satellite Operator RFI Alert Network in 2009, a system sends an e-mail to all satellite operators belonging to the RFI Working Group whenever an episode of interference occurs. “The idea behind this collective alert network is that the higher the number of eyes on a problem, the quicker it gets resolved,” says Guillemin.

      Through this initiative, which also supported is by SUIRG, collaboration between satellite operators is facilitated. In particular, assistance in mitigating interference events is provided in real-time to operators by their peers. The network has been tested but has yet to be used in a real instance of interference.

      Another area of activity is the development of a databank of reference carriers for geolocation purposes that can be consulted in case of need and to be kept by a dedicated, independent body to preserve confidentiality This database also will include historical RFI information to facilitate troubleshooting. To this end, leading global satellite operators Intelsat, SES and Inmarsat joined forces to form an international, independent body named the Space Data Association (SDA), based in the Isle of Man, United Kingdom. The SDA will store this information confidentially, and operators will be allowed to access the database only when needed, consulting only non-commercially sensitive data. 

      An Issue of Identity

      Another crucial issue in the fight against radio frequency interference is the concept of carrier identification (ID). In its basic form, the idea is quite a simple one: to embed uplinker location or contact information in the uplink signal to facilitate troubleshooting by operators. Its implementation, however, is rather more complicated, as it involves the participation of actors from the entire satellite chain: from equipment manufacturers to operators and integrators.

      On Nov. 18, an industry-wide meeting hosted by Intelsat took place to endorse the adoption of carrier ID technology by equipment manufacturers. “Three sub-committees looking respectively at video, data and VSAT communications were formed with operators and equipment manufacturers,” says Guillemin. The video initiative is reported to be proceeding speedily due to fact that since 2008, the World Broadcasting Union’s International Satellite Operations Group has been making recommendations on carrier ID initiatives. Industry members seem to have been taking this onboard. On the data and VSAT side of the satellite family, the carrier ID initiative is not as advanced, though progress is being made. 

      Training the Human Factor

      Given the importance of the human factor, it is no surprise that training of technical personnel is seen as a decisive area for combating this problem. “The Schlumberger Global Connectivity Services (GCS) group has long recognized the importance of having their field staff properly trained,” says Andrew Rope, Schlumberger’s remote connectivity training manager. “Our field engineers work to avoid allowing a GCS installation to be the source of interference. All GCS VSAT field engineers are required to participate in a fixed-step, three-year training program, pertaining to both technical and business practices. “For the past three years, we have worked closely with the Global VSAT Forum to integrate the GVF VSAT installer’s certifications into the technical curriculum of our fixed-step program to align our training with industry standards.”

      Training personnel is a paramount component of the initiative that involves the education of personnel in a wider sense. Intelsat, for example, is offering a training incentive for technicians employed by its customers. “We endorsed a training and certification program with two industry-leading vendors: the Global VSAT Forum and BeaconSeek. We offer training to our satellite newsgathering customers through BeaconSeek’s SlingPath and through GVF’s program to educate VSAT technicians on proper equipment installation and operational parameters,” says Guillemin. “Our goal is to provide training to 1,200 engineers from our customer base within the next three years. We expect that this and other efforts will create an industry momentum for other operators to join in the training effort and that industry awareness of this problem will be raised.”

      Giovanni Verlini is a communication executive and freelance journalist based in Europe. Email: giovanniverlini@hotmail.

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