But this broad support inevitably means network deployment strategies will vary widely, as operators around the world face decisions on how to manage the long transition from todays 2G and 3G networks.

For equipment vendors and, by extension their silicon and subsystem suppliers, the challenge is to meet these diverse operator requirements, yet still maintain standardized product portfolios that require a minimum of customization. Inevitably, this is shifting the value in basestation products (eNodeBs) to software-defined systems.

This requirement for flexibility is nuanced by vendors having to take a view on the appropriate balance between software upgradeability and hardware refresh. In essence, the decision is about the extent to which vendors should invest in more powerful, programmable systems and components at higher upfront cost, versus their ability to deliver less flexible, hardware-optimized products at lower cost that may need to be refreshed sooner. The decision hinges, ultimately, on assumptions around deployment scenarios and upgrade strategies, what will create a competitive advantage, and what will deliver an appropriate profit margin over a given timeframe.

To a degree this is an old problem that has faced basestation developers through the ages. Whats new about the transition to LTE is the debate in the market between multi-standard radio access networks (RANs) that integrate LTE with 2G and 3G technologies in the same basestation, and discrete LTE overlay products.

This decision is still up in the air for many operators, and that is reflected in the diversity of todays LTE basestation designs, according to the new Heavy Reading report, LTE Basestations and the Evolved Radio Access Network. Theres also a circular dynamic at play. As operators evaluate LTE they must to take a view on how their overall RAN requirements might evolve, and this will in significant part be influenced by the capabilities of these new basestation platforms and eNodeB products themselves.

The overlay strategy is the fastest, cheapest, and easiest way to roll out LTE, and this approach will likely lead in early deployments. On the plus side, there would be no impact on legacy 2G or 3G networks, the systems would be less complex, and best of breed equipment could be deployed. On the down side, this approach would have higher overall opex costs and long-term higher capex costs.

In contrast, the multi-standard RAN approach has lower opex, better coordination among the 2G, 3G, and 4G systems, a single backhaul pipe, and one operations, administration, and maintenance (OA&M) to manage. There may be higher upfront costs, however, and operators may feel they do not have enough visibility into future RAN requirements at this stage, and especially given the current economic climate.

For this reason the most competitive eNodeB product portfolios will support both types of deployment. This confers advantage on the larger vendors that have the scale to support broader product sets and have more incentive to gracefully migrate their installed customer base.

Among the major cellular infrastructure vendors, Ericsson AB, Huawei Technologies Co. Ltd. , and to some extent ZTE Corp. are in the integrated, multi-standard basestation camp with their LTE RAN product designs. This categorization is crude, however, in that each of these vendors has very different design principles in key areas.

Meanwhile Nokia Siemens Networks offers a product that integrates WCDMA and LTE (but not GSM) and Alcatel-Lucents current LTE equipment is designed for overlay network implementation, but could very likely add a 3G software load over time.

NEC Corp. and Nortel Networks Ltd. products will be LTE focused, but will look to align with their installed 3G base as appropriate. Fujitsu Ltd. and Motorola Inc. are developing dedicated LTE products targeted for overlay deployments and hope to take market share with early contract wins.

Gabriel Brown (brown@heavyreading.com) is a senior analyst at Heavy Reading, a market research organization offering quantative analysis of telecom technology to carriers, service providers and vendors. It is owned by United Business Media, owner of TechInsights, publisher of EE Times Europe.

This story appeared in the February 2009 print edition of EE Times EuropeEuropean residents who wish to receive regular copies of EE Times Europe, subscribe here.

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