Mitigating Interference
One of the only drawbacks to increased VSAT network usage increases around the globe is a parallel increase in incidents of radio frequency interference, which can disrupt data transmissions and other critical communications services, hindering business growth. The highest rate of interference occurs in fast-growth regions such as Africa and the Middle East, and throughout such regions, there is an ongoing challenge to help VSAT users understand how incorrect installation — substandard antenna assembly, mispointing, cross pole and poor line-of-sight considerations — can lead to interference.
To promote an interference-free space environment, 19 satellite operators and industry associations such as the Satellite User Interference Reduction Group and the Global VSAT Forum have joined forces to reduce interference on a global level. In 2009, Intelsat launched the Intelsat Interference Management Initiative to increase awareness throughout the end user community and lead an effort to ensure technicians obtain proper training, increase the quality of data and communications regarding interference events and guarantee proper alerts are implemented to reduce reaction times when interference occurs.
The first step toward maintaining an interference-free space environment is to provide training for the user community. Operator’s are sponsoring training sessions of the Global VSAT Forum’s online training program which educates technicians on proper equipment installation and operational parameters of VSAT networks. Rodrigo Chagas, an installer with Telespazio Brasil, says the training was useful in helping young technicians grow within the telecom sector. “There were some [interference] concepts of which I was not aware until I completed the online coursework. The training definitely helped me become more effective when troubleshooting [interference] cases.”
All in a Name
Perhaps the term VSAT is the industry’s worst enemy. Very small aperture terminal stresses antenna size, not what the device can do. Imagine Cisco’s success if they had named their product “small metal box with blinking lights”. In a sign of the times, Hughes has begun referring to their products as satellite routers. “Our products are very IP-centric,” says Rehbehn. “We looked over all of the IETF [request for comments) for features and functionality and can count over 50 that we support. We are constantly striving to improve the performance of our routers. We now support a satellite router that works on a terrestrial link.”
Likewise, Spacenet has embraced routers in a big way. Working with Cisco, Spacenet developed several years ago a plug-in module which goes inside a Cisco router. In the event the terrestrial connection fails, the traffic fails over to the satellite connection. Katz notes Spacenet’s development of advanced routing protocols, such as BGP and VRRP (virtual router redundancy protocol). The latter allows two routers to reside on the same remote network and to back each other up if one fails.
These advanced routing protocols allow network engineers to incorporate VSATs into their terrestrial networks and use the features and functionality they are familiar with. A good example of network integration between VSAT and terrestrial networks are the iDirect networks deployed by Verizon, BT, and Orange. iDirect’s support of MPLS allows traffic to be routed seamlessly across the carriers’ MPLS network.
While retail point of sale and lottery networks have not gone away, they are not the only applications which are well suited for VSATs anymore. Cellular backhaul, mobility, business continuity, and Internet access will continue to fuel the market for satellite communications, making VSATs relevant for many years to come.
Greg Berlocher has been active in the satellite industry for twenty five years and is the President of
Transcendent Global Networks LLC.
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