With over 12 submarine fibre optic cables and more than 30Tbps of network design capacity at the submarine landing points in sub-Saharan Africa by 2013, a debate is raging on whether satellite systems will continue to play a role in Internet connectivity in Africa. The truth of the matter is that even developed countries, such as the United States of America, still utilise communication satellites in areas that cannot be reached by fibre optic cable. It is safe to assume that communication satellites will continue to contribute to the Internet connectivity and other communication needs of Africans, ad infinitum. That said, it is estimated that 99% of all global Internet traffic is routed over submarine fibre cable  while the statistic was almost reversed in favour of communication satellites for a long time in Africa.
With innovative new satellite technologies coming into play we should expect that, while fibre optics will play a significantly more dominant role in inter-city, cross border and International connectivity, satellite systems may play a more significant role in Africa than global trends suggest. We note that even in areas of the continent where fibre has been deployed, satellite systems are being used for redundancy.
The satellite vs optical fibre debate
First we outline the rationale behind the investment of billions of dollars in the development of submarine cables around Africa and terrestrial long haul networks within the continent of Africa when communication satellites are already available.
The number one and most important rationale for operators to incorporate fibre in their networks is the need for higher transmission rates. There is just not enough capacity on satellite systems to transport all the traffic generated by the ever insatiable bandwidth demand and the expanding mobile and wire-line access networks.
Providing broadband Internet connectivity to hundreds of millions of Africans will require backbone transmission networks with hundreds of Gbps of capacity. Each time operators increase their broadband offerings to higher data rates, say from 2G to 3G to 4G, this in turn pushes the requirements of the transmission backbone networks. This explains why International telecommunication standards organisations have ratified standards for 100Gbps per channel in optical networks and are working on 400Gbps and 1Tbps.
Such high levels of transmission capacity would require a very large satellite fleet. According to data tracked by the Union of Concerned Scientists  there are approximately 500 commercial communications satellites currently in use in the world with an average life expectancy of less than 15 years and ranging in throughput from 1Gbps for conventional Ku-band to 10Gbps for Ka-band and 100Gps or more for next generation Ka, V and W band systems. If the average satellite has a capacity of 5Gps, the entire global communication fleet would have a capacity of 5Tb/s of capacity. This means that all the capacity in the entire global commercial communication fleet can be transmitted by a single pair of optical fibre using 50 channels of a Dense Wavelength Division Multiplexing (DWDM) system, each transmitting at 100Gbps. It therefore makes sense for African operators to include optical fibre in their networks, at least for those links where a lot of capacity has to be transmitted.
Limited capacity on satellite systems implies higher cost/bit of satellite capacity compared to fibre. This has a profound impact on the cost of satellite broadband. As an example, a 4Mbs VSAT Internet subscription in South Africa costs more than $2 000 per month for capped download.
Latency is another disadvantage of geosynchronous satellite systems that orbit the earth at 35,786 km above the earth. Latency for these satellite systems range from 540ms to 800ms and is problematic for data download, voice over Internet (VoIP) transmission, gaming and online trading. High speed trading is an area which is seriously impacted by latency. A 1 ms advantage in latency can translate into $100 Million per year advantage for large trading firms. It is therefore inconceivable for a high speed trading company to operate over a satellite Internet connection.
Rain fade is another impairment that affects satellite but does not affect fibre optic communications. At the higher operating frequencies of Ku and Ka-bands, satellite signal strength may be affected by heavy rain conditions. Ironically, the higher frequencies which are capable of more capacity are more degraded by rain fade. Rain fade occurs when satellite signals are attenuated, or weakened as a result of interference caused by raindrops that absorb and scatter signals.
Satellite has lower life expectancy than fibre. While the life expectancy of a communication satellite is 15 years or less, that of an optical fibre is 25 years or more .
The main advantage of satellite systems is coverage as they can be configured to cover any part of the world where fibre may not be deployable. Today, satellite communications can deliver voice, video, and data that can be accessed anywhere in the world.
Next Generation Satellite systems:
With more capacity available to offer higher speeds at significantly lower costs, next generation satellites will play a more pivotal role in provisioning high speed Internet connectivity to Africa, especially where mobile broadband access is not readily available. The proposed SWANSAT and O3B systems have the potential to play a more significant role than conventional satellite systems.
Quietly, over the last fifteen years or so SWANSAT Holdings and its vendor IOSTAR Corporation of North Salt Lake, Utah, have been developing a plan to launch a constellation of 14 very high powered telecommunications satellites licensed for global provision of two-way high speed Internet access. The constellation is called the Super-Wide Area Network™ Satellite (SWANSAT) System.
If and when the ultra-modern system becomes operational, it will offer revolutionary new ICT applications including computer networking, intranet services, on-orbit secure and encrypted data, video and audio entertainment, Direct Broadcast Service programming, pay-per-view programming, educational and distance learning programming, medical information. Contact us
if you need more detailed information on the SWANsat programme.
O3b – The Other 3 Billion:
O3b Networks is a satellite service provider developing a new global Internet backbone for telecommunications operators, Internet service providers (ISPs), and enterprise and government customers in emerging markets. The O3b Networks system is going to target billions of consumers and businesses across 177 countries with lower-cost, high-speed Internet connectivity. The system is being funded by investments and operational support from SES, Google Inc. Liberty Global, HSBC Principal Investments, Northbridge Venture Partners and Allen & Company.
Because the O3B Networks satellite systems will orbit in the Medium Earth Orbit (MEO) between 10, 000 and 15, 000km from the earth, the latency is significantly lower than that of geosynchronous satellites which comprise the majority of communication satellites. O3B has a potential of offering services with significantly improved quality than geosynchronous satellite systems, ceteris paribus.
Although O3B has marketed their systems as comparable to fibre, the capacity has been reported to be 84Gps on 8 satellites or about 10Gps per satellite and can hardly be compared to optical fibre.
Fibre will eventually play a dominant role in communications in Africa, especially in global, national backbone and metropolitan networks. We expect satellite systems to continue to play an important role, especially where fibre will not be deployed. The emergency of innovative new satellite communication technologies is likely lead to satellite systems playing a more significant role in Africa than anticipated from global trends.