The number of mobile users worldwide is expected to grow by almost 1 billion before the end of 2008, most of whom will be in new-growth markets or remote areas of mature markets. Many of these new subscribers may initially spend as little as USD 5 a month. This presents operators with the formidable task of building networks that are both cost-effective and scalable, yet offer the quality required by tomorrow's demanding applications.

To help operators fulfil these objectives and capitalize on growth-market opportunities, Ericsson has developed Expander. Bodil Josefsson, program manager, explains: "Expander is a package of selected radio and core-network components from Ericsson's extensive GSM/EDGE and CDMA2000 portfolios, enhanced by new and unique features in order to provide cost-effective and coverage-optimized technology."

The strategy behind Expander embraces the whole network with a focus on radio coverage, since minimizing the number of sites is crucial in reducing total cost of network ownership. "Consequently," says Josefsson, "among the most important features of Expander are coverage enablers, which permit larger cell areas and allow the tailoring of transceiver capacity to cell areas where users tend to congregate." 

Josefsson says radio capacity may be boosted up to 15 times with just one site visit to insert a single unit. That capacity may in some instances be increased remotely using software, "all with the objective of reducing the operator's operational costs (opex)."

Just as important as downlink but often neglected, says Josefsson, is the uplink performance of the radio network. This is why Expander includes advanced radio-network functions, such as four-way diversity, that help signals get picked up at greater distances from the base station: "Mobile phones today offer comparatively low output power because terminal vendors put priority on long battery life. Moreover, the new growth markets or untapped segments of mature markets for which Expander has been developed often share rural characteristics that require more sensitive receivers in the base stations."

Josefsson argues that lower total cost of ownership is not attained simply by picking the cheapest base stations without considering performance. "Comparing base stations with different functionalities is like comparing apples and pears," she says. "Moreover, the radio base station accounts for only 25-35 percent of the total cost of a typical radio site, so to minimize the number of radio sites deliver far better savings."

Apart from these radio-network features, Ericsson Expander also includes core-network features that support smooth expansion from single nodes to large configurations as the new growth market develops and matures. Josefsson explains that the use of mobile softswitch solutions is important for cost-efficient coverage: "It enables local switching, which saves transmission costs for operators. Instead of letting all traffic pass through centrally located MSC’s, media gateways are deployed in rural areas, keeping the server capacity in the urban areas."

In addition, Expander includes transmission features that support low-cost network expansion in new growth markets and rural areas, and keep opex to a minimum. Josefsson says: "In remote areas, it is often more cost-effective to use microwave transmission links instead of cables. The base stations in Expander are designed for integrated access transmission and efficient solutions for backbone transmission."

Operators who have installed Ericsson radio base stations manufactured since 2003 (RBS 2106 and RBS 2206) do not need to replace them to enjoy the benefits of Expander, since upgrading to features such as TCC and four-way diversity may be done with a simple add-on.

Ericsson Expander has been delivered to a number of operators worldwide. One of the recent buyers is Colombian operator Colombia Telecomunicaciónes, where President Alfonso Gómez says: "With the implementation of Ericsson’s Expander functionality, our coverage has multiplied by four, and we have been able to reach new geographical areas where coverage costs traditionally were very high with traditional solutions."

Read more on Expander here.