Patrick Omutia of the Kenya College of Communications examines how the convergence of information and communications technologies and industries provides opportunities for African development. The international context is provided by the twin phenomena of liberalisation and globalisation. Africa's position is recognized as grim with low product penetration and poor access to services being the norm. A low base offers the chance for adopting appropriate technology using step-changes or leapfrogs that differentiate Africa from the more straight-line profile of European markets.
The worldwide liberalisation of the communications market, coupled with the globalisation trend, offers a great challenge to operators in the field, and especially so to the telecommunications industry, where several services are converging. This convergence has seen the emergence of what is commonly referred to as Information and Communication Technology (ICT), where user demands are higher and more vast, whilst mobility is also demanded by users for service continuity. Africa's position has been a grim one, for both telecommunication service providers and their users. Statistics on the latter indicate that whereas Africa's population (at 800 million) is 15 per cent of the world's population, Africa has only 2 per cent of the world's telephone lines and Internet connectivity in Africa is the least in the world at less than 1 per cent. It must be recognised that whereas this grim picture may be a direct reflection of the economic powers of the users, a great contribution is the result of the telecommunication operators' inability to expand/modernise their networks. At present, however, many Incumbent Operators (IOs) are faced with competition after their local telecommunications industries have been liberalised and second operators licensed. In many cases, strategic partners have been brought in and IOs are expanding their networks through such investments. In any network expansion, it is of critical importance that the most cost-effective technological options are studied and carefully selected. This selection is not a simple task, given that in the past few years, the ICT industry has seen a tremendous evolution of technology in both customer and network equipment. However, it must be appreciated that this evolution offers an opportunity for African telecommunication service providers to leapfrog into the information age by adopting appropriate technologies, thereby avoiding the need to develop progressively, as has happened in the developed world. The rest of this article examines user trends and the available technologies in the ICT industry and identifies the way forward for Africa. User Trends - The E-world The explosion of Internet traffic (doubling almost every 100 days) has resulted in the desire by users to have services transferred to their premises as opposed to the traditional business set-up where consumers physically move to get services. This is seen by increased demand for e-mail and e-commerce. Other areas include e-education, e-medicine and e-libraries. Since computer networking has continued to rely on telecommunications networks as their transmission media, the aforementioned user trends only place greater demand on telecommunication operators to offer more reliable and faster backbones for the Internet. Multimedia To compete today, telecommunication operators worldwide are forced to deploy networks that can meet multimedia service demand. Multimedia has been defined in different ways and means different things to different people. The common feature, though, is that multimedia information ultimately plays directly to the sensory needs of a human end-user. Moving images and sound (vision and hearing), text and graphics, animation, etc., that are combined to form a synergetic presentation or interactive session, are examples of multimedia applications. In some futuristic applications, it is possible that more than just the vision and auditory senses will be brought to play, as in the association of human movements and expressions with the manipulation of distant robotic entities for applications such as mechanical repairs and surgery. Multimedia imposes a stringent set of implications on required network characteristics. Bandwidth, timing sensitivity, latency, connection establishment time and error performance are all critical issues faced by the network that supports multimedia. A network must support multiple streams of information per user (some bursty some non-bursty, some high bandwidth and others low bandwidth) to satisfy multimedia-rich communications. Many such streams will be needed simultaneously per user or site, with each being routed to and from separate destinations. This type of multi-speed, multi-point, multi-stream level of communication can only be supported on networks that can apportion their bandwidth and route information flexibly as needed, on-demand. Internet Telephony Internet telephony, the transport of telephone calls over the Internet, also referred to as Voice over Internet Protocol (VoIP), is a powerful and economical communication option that integrates both telephone and data networks. For lack of operational and technological standards the use of VoIP is not easy to quantify, but it is believed that this telephony medium is quickly gaining popularity. In the evolution of Internet telephony, three topologies have been used: (i) PC-to-PC communication (ii) PC-to-phone (iii) phone-to-phone communication The ultimate objective of Internet telephony is, of course, reliable high-quality voice service, the kind that users expect from the Public Switched Telephone Networks (PSTN). At the moment, however, that level of reli-ability and sound quality is not available on the Internet, primarily because of bandwidth limitations that lead to packet loss. Such packet loss shows up in the form of gaps or periods of silence in the conversation, leading to a clipped-speech effect that is unsatisfactory for most users and unacceptable in business communications. It is envisaged that over the next few years, the communications industry will address bandwidth limitations by upgrading the Internet backbone to ATM. Emerging Technologies Access/Transmission Technologies. The four main access media are: - (i) copper wire (ii) coaxial cable (iii) fibre-optic cable (iv) wireless communication. Copper Wire Its characteristics include: o It has a relatively low-bandwidth; o It is usually configured as dedicated physical links; o It easily allows switched digital access; o Amplifiers are need every 5 to 6 km to transport digital signals. Coaxial Cable Similarly, it has the following characteristics: (i) It can distribute analogue and digitally encoded signals up to 1 GHz over distances of 300 to 600 m using low cost amplifiers and passive components (ii) It is subject to high loss (which is frequency-dependent). For distances greater that 300 m, signals in coax networks must be amplified and equalised (which in turn adds noise and distortion). Over long distances, the signal quality becomes unsatisfactory. Fibre-Optic Cable Due to the reasons listed below, fibre has emerged as the transmission media of choice (i) It offers very low attenuation; (ii) It offers high bandwidth; (iii) It is low cost; (iv) It is light-weight; (v) It gives immunity from electromagnetic interference. Many fibre-optic systems today use a non-standard analogue format for encoding the signals they transport. However, there is a strong trend in industry to migrate to a synchronous digital format called SONET (Syn-chronous Optical NETwork) or SDH. Wireless Communication Generally refers to several forms of radio-based services that serve as alternatives to terrestrially based electrical or optical cable technology. Wireless technologies span a wide range of bandwidths. Leading examples of narrow-band systems include: (i) Cellular telephones: typically operate in the 800-900 MHz frequencies range over distances of a few miles. Provides the largest cell sizes and allows rapid handover between adjacent cells as the user moves. (ii) Cordless telephones: operate in the range of 46-49 MHz or 900 MHz, with a range of a few hundred feet. Cordless cells are very small and provide no hand-over between cells. (iii) Personal Communications Service (PCS): operates at 1.5-1.9 MHz, with a range of about 1,000 feet. PCS falls somewhere between the two extremes of the two systems above, with lower power and smaller cell sizes than cellular. PCS does allow some movement between cells, but usually only at slow speeds (such as walking around a neighbourhood or office complex, but not while driving a car at high speeds). All these are based on radio transmission systems using different frequencies and power, resulting in different effective distances. Each of these wireless technologies employs a base geographic area, known as a cell, with a fixed antenna for access into the network, which is provided by terrestrial electrical or optical transmission systems and narrow-band switches. Wide-band radio systems include terrestrial microwave radio and satellite systems. (i) Microwave radio systems operate at 4, 6 and 11 GHz and have repeater spacing of 20 to 30 miles (ii) Satellite systems use a satellite in a geo-synchronous orbit operating with the same frequency bands as microwave radio. Switching Technologies The most common types of switches are: (i) Circuit switches (ii) Packet switches Circuit switches: These use a switching mechanism where a dedicated circuit is established between two end points before the call can commence and disconnected when the call is completed. The switches are used primarily for voice and narrow-band communications. Disadvantages of circuit switching include low bandwidth, inefficiency, inflexibility and high cost. Conclusion Packet Switches: In packet switching, dedicated communication is not established between terminals that wish to communicate. Messages are split into discrete packets each containing routing, sequencing and control information to enable the message to be formatted at the receiving station. Packet switching, which has been widely used in computer communication networks, is giving rise to Asynchronous Transfer Mode (ATM), which is a Broadband Integrated Services Digital Network (B-ISDN) transport technology. ATM definitely holds promise for switching not only high-speed data and video but voice as well.