GSM is by far the most widespread cellular technology in Africa offering voice communication facilities to millions of people who are not able to receive a reliable landline service. In a limited number of countries, CDMA 2000 installations are also in place to offer users extended services to match third-generation (3G) data and voice services on offer in some developed countries.

"One of the problems network operators in Africa experience is the broad dispersion of people, particularly in rural areas," says Hendrik Bredenkamp, Manager: Mobile Systems, Ericsson Market Unit sub-Saharan Africa. "It only makes sense to install a GSM or CDMA base station if there are enough potential customers in the coverage area to make it financially viable in the long term."

Obviously this restricts the number of customers that operators can sign up and the communication capabilities of many people who may wish to be connected.

"For operators in this predicament, Ericsson has a solution," says Bredenkamp. "CDMA 450 is a low-frequency version of CDMA (operating at 450 MHz), that offers a larger footprint per base station (about 20% larger than that of a normal GSM base station). Using this technology, operators can expand the limits of their networks into rural areas."

Whereas a standard GSM base station covers a radius of about 35 km, the maximum range of a CDMA 450 base station is 49 km. The difference in the number of people now within range is enormous, making even a loss-making coverage area profitable.

In addition, since it is CDMA technology, operators are able to expand their voice services and offer data solutions as well. The technology can be setup for use as a wireless local loop, for example, or as a high-speed, high-bandwidth wireless DSL solution. CDMA 450 has most successfully been rolled out for fixed terminal solutions like the WLL but have some drawbacks on mobility (Cell shrinkage/breathing effect).

The significance of the 450 MHz frequency range is simple. Because lower frequency waves can travel further without significant degradation, fewer base stations are required and more people will fall into a coverage area. And this means more subscribers and increased revenues.

"Implementing the Ericsson CDMA network translates into a lower cost of ownership for the network operator, high-quality voice performance and data capabilities over longer distances for users, due to the fact that Ericsson uses common core equipment that has also been deployed in their GSM solutions. This common equipment brings to the fore a number of advantages for the operator like reduced training, equipment being proven and reliable, and equipment being produced in volumes i.e. bring prices down."

CDMA also offers scalable coverage for areas where operators want to offer services in, but are concerned about the financial viability," Bredenkamp says. "CDMA 450 is not the solution for every situation, but has proven very successful in many rural rollouts around the world, including in Russia, Belarus and Romania."