It is only nine months since the Open Base Station Architecture Initiative (OBSAI) added WiMAX specifications to its standards platform, but the technology is becoming increasingly important in its roadmap, with over one-third of its 130 members now actively working with WiMAX.

The emergence of carrier systems that are united by IP but fragmented between different physical networks is a boost for OBSAI since it makes it even more urgent to reduce equipment and development costs through standard integrated platforms. Thus it is unsurprising that the initiative has leapt eagerly on WiMAX and the prospect of combined 802.16/3G networks.

OBSAI chair Tero Mustala (of Nokia) commented: "A chief benefit of the OBSAI open interface specifications is that they have been devised to go beyond existing technologies so that they are virtually future proof. We expect to have WiMAX fully integrated into the full range of OBSAI specifications, by the first half of this year."

R&D costs
Despite the work of organizations like OBSAI, so far the vendors have been hesitant to take the plunge into a common, plug and play architecture for 3G base stations, claiming that these products remain too complex to be commoditized, and seeking to cling to competitive edge while they can. Yet R&D costs are too high to be viable at the cost levels being demanded by the major operators, especially as manufacturers seek growth in price sensitive emerging markets - where they will come up against suppliers like China's Huawei, which is used to selling low cost products, and is now looking to grow outside its native land. Even in the developed markets, operators know that their own differentiation will increasingly come from applications, which means shifting the balance of their own investment away from base stations to software, content and application servers. "We are looking for really cheap base stations [so that] we can spend all our money with the IT vendors," Hutchison 3G said, only semi-flippantly, at a conference last year.

Yet R&D costs have gone up, not down, for the major vendors, rising from 13% of sales in 1999 to 17% in 2004, partly because of the need to upgrade the range to support 3G, forcing the suppliers,however reluctantly, to get behind initiatives to promote commonality among base station components that are not already standardized by the 3GPP process - hence OBSAI.

The organization is one of two working on a set of open internal interface specifications for base station architecture and module specifications. Its work covers the areas of transport, control, baseband and radio. As base station makers' R&D costs escalate and their margins decline, there is increasing pressure to create common architectures and achieve differentiation through software and services rather than hardware design - although OBSAI has adopted a self-certification approach rather than a formal standards compliance program, partly to save time to market.

Joseph Cleveland, director of systems and standards at Samsung and a member of OBSAI's management board, said the work on the WiMAX interface was a "major technical effort" but important because of the likely major role that 802.16 will play in cellular base station backhaul and later in multi-network IP systems. The other main effort to standardize base station modules is the Common Public Radio Interface (CPRI) initiative, which has currently not made any WiMAX moves in public, although members like Xilinx - which supports both groups - say that CPRI is sufficiently flexible to transport WiMAX data between RF card and baseband just as OBSAI does. There is pressure from many quarters for OBSAI and CPRI to merge their efforts. "If both sides had the political will to come closer together, it could still happen," said Mustala, who claims the groups are technically close together.


Nokia, with its customary adeptness in influencing industry bodies, took the initiative in 2002 when it created OBSAI, which breaks up the base station into standardized modules. Its members include Alcatel, Samsung, LG Electronics, Hyundai and ZTE, plus most suppliers of chips and modules for the sector.

However, Ericsson and Siemens, supported by Huawei, NEC and Nortel, started an alternative initiative, the CPRI, which focuses only on UMTS and defines a single interface between the digital and RF portions of the base station, reducing costs particularly in the most expensive and power hungry element, the RF power amp.

This article originally ran in Wireless Watch, a publication of Rethink Research. Reproduced with permission. For information on the weekly Wireless Watch Newsletter and other Rethink Research products and services, click here.