SPECIALIST ARTICLE

Communications Infrastructure for Remote Locations

Options for Africa

By Mike Jensen

A wide variety of options is now available for providing connectivity to  remote locations in Africa.

The connectivity options can be broken down into three major areas:

1. Narrowband systems. These operate on the HF, UHF and VHF wavebandsn (10-100Mhz) and usually provide low bandwidth connections between 2.4Kbps and 19.2Kbps. However because of the low frequencies these systems use they offer the advantage of long range and immunity to obstacles. HF-based systems are capable of providing connections over 1000s of kilometres and agencies such as the International Red Cross & Crescent use these systems to provide direct links from Geneva to their field offices all over the world. UHF and VHF systems provide higher bandwidths over shorter ranges, usually up to about 40kms but depending on the power of the transmitter 100kms is possible. Equipment costs for the user are relatively high for these systems - usually around $1000-$2000.

2. Medium bandwidth systems. The two main technologies in this area are the mobile telephone standard – GSM  and corDect. These systems operate in the 900Mhz to 1800Mhz frequency range and provide higher bandwidths than the narrowband systems, between 9.6Kbps (for the basic GSM service) and 115Kbps for the newer HSCD and GPRS mobile protocols. The range of these systems is more constrained than the narrowband systems –  usually between 25 and 35kms, but they are also immune to most obstacles in the path of the link. Clearly, using the GSM network can be costly for sustained Internet access because of the high usage charges levied by the mobile operators.

3. Broadband systems. These use higher frequencies (usually between 2.4Ghz and 5.8Ghz) which can carry more data (128kbps-54Mbps) but distances are more limited – 70kms is possible, but 10-15kms is more easily achievable. In addition the link path must have a clear line of site between the two antennae and any obstruction will interrupt the circuit. However with the use of repeaters and mesh networking it is possible to extend the distance or route around obstacles.

 Mixed Bag

Satellite-based systems are also a popular means of providing connectivity in remote areas, however these are more expensive than terrestrial systems when provided in a competitive environment. It is now possible to obtain a 2-way VSAT terminal for $2000-$3000 with monthly subscription rates as low as $200/month, however the charges are usually dependent on the volume of data that is transferred - $200 will only buy about 2Gb of satellite-based data on these systems. There is also the potential to share the costs of a satellite link by combining the system with one of the above terrestrial wireless technologies to redistribute the bandwidth to local users. This will also increase the economies of scale and reduce the costs of satellite bandwidth.

 There are also a variety of mixed technology or hybrid systems that can be used to provide remote connectivity. The most popular of these is to use a simple satellite TV or Radio antenna to receive data at high speed (up to 400Kbps) and to use a low bandwidth phone line or narrowband wireless link to provide the return path. Sentech's Infosat and Worldspace are examples of these services. It is also possible to use the terrestrial radio or TV signal's carrier frequency to transmit data, however this technology has not been deployed in Africa.

Renewable Energy for ICTs

Sources of power - for long a problem in many parts of Africa - can be found in many established and innovative technologies, including:

Photovoltaic/Solar cells

 Solar / photovoltaic details

$6000 setup will power 8 PCs plus neon lights

Expected 12 Year Life

Even on-grid cab makes sense – 3-4yr payback period

User involvement in maintenance necessary

Independent Power Producer policy assists sustainability

Support from PV cell manufacturers is limited

Batteries and Solar cell costs could be reduced - cells cost $0.70/watt, sell for $3/watt

Import duties in many countries, recently exempt in SACU

Other Options

PDA solar rechargers - $15

Small scale hydro – pioneered in Vietnam

Windmills

Village biomass generators

Diesel/petrol generators

Human energy – bicycle powered WiFi & laptops, wind-up radio/cellphone charger

Fuel Cells

Initiatives

· UNEP ICT-RESD (ICT applications of Renewable Energy for Sustainable Development) Task Force

· Namibia Schoolnet solar schools project schoolnet.na

· Solar Electric Light Fund (SELF.org)

· Winrock International manual winrock.org

· UNIDO GEF renewable energy for ICT project in Zambia