Satellite vs optic fibre – is there a case?

Even the launch of South Africa’s first geostationary satellite “New Dawn” drew little attention. Perhaps because the original launch was aborted due to an anomaly in the launch sequence, or are satellites being dismissed as old fashioned relics of the past?

Those that believe that satellites are something of the past should think again. Satellites are here to stay and still fulfill an important role in the world’s telecommunication  infrastructure,  now and in the future. The recent devastating earthquakes and tsunami that hit Japan illustrated how vulnerable submarine cables are, as there were 20 different breaks in as many as six different cables. Without satellites Japan would have been hard pressed to communicate with the rest of the world.

Having said that, vulnerability to environmental damage by sub-marine cable systems does not make them less important. As carriers of large capacity, satellites also have their problems. When the sunspot cycle reaches its peak and violent solar storms hit the earth’s atmosphere, satellites become vulnerable. So in fact we need both systems!

Satellites are big business

Intelsat alone will be launching eight satellites over the next two years. New Dawn successfully launched on 22 April 2011 is the first of the largest satellite programme in Intelsat’s history. The satellite investment programme is expected to provide enhanced high-powered capacity to Intelsat’s global fleet with Intelsat 18 planned for launch later this year.

The Ariane 5 vehicle lifted off from Kourou, French Guiana at 17h37 (EDT) on 22 April 2011, followed by spacecraft separation from the launch vehicle at 18h12 and signal acquisition at 18h29. A textbook launch!

New Dawn satellite is owned by a joint venture between a consortium led by Convergence Partners and Intelsat. The satellite’s 28 C-band and 24 Ku-band 36 MHz transponder units are designed specifically to supply critical communications infrastructure to African nations.

Operating from a geostationary orbital slot at 32,8º East, New Dawn will be ideally positioned to serve Africa through a payload optimised to deliver new capacity for voice, wireless backhaul, fixed line and wireless infrastructure, broadband and media – the fastest growing satellite-based applications in Africa.

New Dawn will be integrated with the resident Intelsat fleet, allowing expansion and enhancement of vital communications services that are provided by operators to business and consumers throughout Africa. Andile Ngcaba, chairman of Convergence Partners, said, “The satellite will not only deliver crucial services specifically tailored for Africa, it will also herald the dawn of a new era where Africans enjoy far greater involvement in the space communications industry.”

VSats play a vital role

Just think about how an auto bank, in a remote area or at a sporting event, allows you to access your account and draw cash or how a pharmacy in a small town or village communicates with medical aid companies before dispensing medicine. Have a look around the building or on top of the roof and you will spot a VSat dish.

Telkom is a large player in the African VSAT space. The company operates over 6813 VSat terminals on its SpaceStream national and SpaceStream multinational networks – offering each customer a fully managed, dedicated bandwidth MPLS VPN network with coverage anywhere within South Africa or Africa. These networks are specifically designed to each customer’s requirements, being anything from a primary network to an overlay or backup for a terrestrial network. They also offer the very latest in satellite technology to overcome the time delay limitations of geostationary satellite networks. The networks can be in any combination of star, mesh or multi-star configuration. Flexibility and expandability ensures expansion to meet future requirements.

Telkom also provides satellite-based internet and voice services to over 4512 consumer customers via its SpaceStream Office and SpaceStream Express networks. Both offer always-available 512 kbps best effort internet access (IP) with SpaceStream Office also offering up to four voice and/or fax lines. SpaceStream Express and Office was primarily designed to deliver internet access to areas with unreliable or no terrestrial infrastructure. The internet access service has to be used in conjunction with the services of an internet service provider (ISP). Currently both services are usage capped, with caps up to 12 Gbps per month on offer.

About competition with cable services, Telkom’s Steve Lewis said that they are experiencing downward pressure on satellite revenue, but it is still big business. “We are in satellites and we plan to stay there. It is a necessary part of telecommunications environment.”

Telkom has recently invested in a new Hughes’ HN platform with HX overlay which is a great advance on older systems. The HN system is the Hughes flagship product for implementing a wide range of large scale satellite broadband networks to serve enterprise, government, and consumer/small business markets. The core of the HN system is the HN network operations centre (NOC) which manages high-speed IP traffic flow among terminals. It is fully compliant with IPoS/ DVB-S/S2, including adaptive coding and modulation (ACM). ACM matches modulation, coding and other signal and protocol parameters to the conditions on the radio link, compensating for path loss, and interference from signals coming from other transmitters. The sensitivity of the receiver and the available transmitter power margins are managed. This greatly contributes to the mitigation of rain fade which is particularly prevalent on the Ku and Ka- bands.

The new platform offers customers the opportunity to have access to more than one satellite, which means that South African enterprises with business interests in other African countries can have integrated communication networks.

“For financial customers we provide split services, one service via Hartbeeshoek and the other via the Crowthorn teleport. This greatly enhances redundancy. Should one link go down, the other will take over the service. All Telkom satellite services are managed by the NOC in Centurion although the two teleports are manned 24 x 7. Our next development will be to offer a proactive service where we will monitor the services provided to enterprise customers and take corrective action before they may even notice there was a problem in the network.”

“Our African satellite operation is handled by iWay Africa, a company that is owned by Telkom. Using our African subsidiary makes a lot of sense as they are familiar with local regulatory conditions, which in some countries is still challenging. iWay is also able to provide local back-up”, said Lewis.

New kid on the block

Vodacom is a relative newcomer to satellite services. The company started in 2008 and had to build their infrastructure from scratch. Being a latecomer into the market was in many ways an advantage as they were able to home in on the latest technology. “For us it was a priority to build a robust service that would meet modern day requirements”, said Sean Victor of Vodacom Business. “We lease capacity from a number of satellite fleet providers. Our strategy from the outset has been to build a service with full redundancy. We operate two teleports, one in Midrand and the other in Silverton and run our services mirrored. Currently we run both C-band and Ku-band services but we will soon introduce services using the Ka-band.”

Ka-band –the future of satellite communication?

Is Ka-band the future of satellite communication? The answer depends on the kind of service that will operate on Ka-band frequencies. The upside is that it is a larger band and can accommodate many more services, the downside is that it is more weather-dependent than C or Ku-band. The Ka-band uplink uses frequencies between 27,5 GHz and 31 GHz and the downlink uses frequencies between 18,3 and 18,8 GHz and between 19,7 and 20,2 GHz. The Ka-band is a branch of the K spectrum. The term “Ka-band” originates from the German word “kurz”, meaning short.

Source: EngineerIT

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Satellite vs optic fibre – is there a case?