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Despite tremendous growth in the area of mobile telephony, Africa continues to lag behind other developing regions in Internet access. The business opportunity to capitalize upon this Internet Protocol (IP) traffic need has not gone unnoticed. Major communications service providers have been investing heavily in Ka-band communications (the Ka-band is part of the K band of the electromagnetic spectrum) — which can carry more data than lower frequencies and offers additional frequency ranges at already occupied satellite positions — such that next generation Ka-band satellites can be responsive to the burgeoning IP traffic market. However, these Ka- band systems have disadvantages compared to lower frequency solutions; Ka-band systems are much more susceptible to weather due to signal absorption by moisture in the air and by wetness on antenna surfaces. These inherent limitations of the Ka-band hold a special significance for communications in Africa since almost a third of the continent is tropical in climate, and weather patterns across the continent are expected to further increase in variability, including increases in the frequency of extreme events, such as storms. The Paper further explores how the use of TV White Spaces, in addition to the availability of real-time weather information via the notion of “humans of sensors,” could be particularly useful for observing, anticipating, and mitigating disruptions to communications services.
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Enhancement of Communications Resiliency
in Sub-Saharan Africa
Simone Sala, Marco Zennaro, Lisa Sokol, Anna Miao, Robert Spousta, Steve Chan
MIT-IBM Network Science Research Center
Key issues
• Expanding Internet Access in Sub-Saharan Africa
• Ka-Band as a solution to telecommunication needs, with some drawbacks
• Telecommunications & climate nexus in Sub-Saharan Africa
• TV White Spaces
Mobile data traffic:demand for spectrum
Global mobile data traffic will increase 13-fold between 2012 and 2017. *
Two-thirds of the world's mobile data traffic will be video by 2017. *
Spectrum crunch
* Cisco VNI Mobile Forecast 2013
Internet in Sub-Saharan Africa
ICT Price Basket, IPB* :
• -18.3% 2010/2012 (-18% PvS, -23.5 PS)
• Africa: -55% Broadband, -25% Mobile
Still Africa is behind other developing regions in Internet access
* ITU 2013
Internet in Sub-Saharan Africa
Aff
ord
ab
ility
Report
20
13
Satelite Telecommunications: important for Africa?
In 2006, it was noted that “29 out of 55 African countries and territories get more than 80% of their total international Internet bandwidth by satellite, and many fixed and mobile operators in the region are also becoming increasingly dependent on satellite for their domestic communications services as well [4].”
Balancing Act Africa 2006
Satelite Telecommunications: still important for Africa!
Repositioning of satellites (the
Inmarsat-4 a.k.a. I-4 satellites) by
Inmarsat between August 2008 and February 2009…
… resulted in mobile service outages during
this period of time.
Did it affect the people on the continent of Africa? Yes!
It also affected the humanitarian aid
community
Ka-Band as a possible solution
• Ka-band allows for increased bandwidth at a lower price per bit and well meets the demand for bandwidth consuming venues, such as video.
• Additional Frequency Ranges
• Meets the demand for Streaming video
• Higher Data at lower price per bit
Ka-Band as a solution… with some drawbacks• Higher frequency Ka-band systems (26 GHz –
40 GHz) are much more susceptible to weather conditions due to “rain fade” signal absorption by air moisture and by wetness on antenna surfaces
• Poorly suited for applications (e.g. classic satelite TV)
• IP traffic degrade under conditions of heavy precipitation, especially during peak traffic times
Ka-Band as a solution… with some drawbacks
Climate variability and change in Africa
• Africa predicted to be one of the regions most affected by extreme climate events
• Uncertainty on nature and extent of climate change in Africa
• Lack of historical climate data
• High ecological diversity (i.e. “Africa is not a country”)
Climate variability and change in Africa
• Rainfall: - increase in annual mean East African rainfall- decrease in much of the winter rainfall region and on western margins of southern Africa. - uncertain impact in the Sahel, the Guinean Coast and the southern Sahara
• Expected increased climate variability:- increase in the frequency of extreme events- increase in heavy rainfall frequency already observed in Southern Africa
Telecommunications & climate nexus
Telecoms
Climate
Monitoring
Resiliency
A new technology on the horizon…
TV White Spaces
In telecommunications, white spaces refer to frequencies allocated to a broadcasting service but not used locally.In addition to white space assigned for technical reasons, there is also unused radio spectrum which has either never been used, or is becoming free as a result of technical changes.
TVWS Propagation advantage
• Lower free space loss• Better diffraction efficiency• Lower building attenuation
TVWS Propagation advantage
TVWS vs WiFi
• In most African cities the unlicensed spectrum used by WiFi is crowded and it is impractical for networking use.
• In rural areas the better propagation characteristics of TVWS means that fewer base stations and towers are required, thus reducing the overall costs.
TVWS deployment in Sub-Saharan Africa
• Google in Western Cape, South Africa: 10 primary and secondary schools were connected to the Internet
• Indigo Telecoms (ISP), Microsoft & Government of Kenya in the Nanyuki region: health care clinic, a library and 3 local schools were connected
• University of Malawi: a school, a hospital and a seismological research center were connected to the Internet.
South Africa
Kenya
Tanzania
Malawi trials
Lighter colors = low/no occupancy of the spectrum; Darker colors = spectrum is used
Conclusion: what we can state today
• Ka-Band’s capacity to carry more data (than lower frequencies) and provision of additional frequency ranges can help expand Internet access in Sub- Saharan Africa
• TVWS very promising technology to expand connectivity, especially in rural and remote areas of Sub-Saharan Africa- Not affected by weather- TVWS free frequencies particularly available in remote/rural areas
Conclusion: open issues• Future research to test effectiveness of TVWS:
- throughput, latency/jitter, resilience in different weather conditions;- power consumption in idle/transmission modes
• TVWS is not a panacea: connection still required for its own backhaul (even though a TVWS network could also be used to reach multiple uplinks)
• Technology bundles needed to serve underprivileged & rural communities- Leveraging local citizenship to tackle the telecoms/climate nexus
