OBSAI – Enabling an open Market for Base Station Modules

Kai Nurmenniemi


Traditionally, mobile network manufacturers have developed proprietary modules for Base Tranceiver Stations (BTS). The key challenge in the future is to create cost effective products for base station manufacturers in order to facilitate the production of new base stations that will allow telecom operators to roll out new services, cost effectively and rapidly. The Technology Group harting and several other companies support this approach.

Monthly data consumption per subscriber (MB)

The Open Base Station Architecture Initiative (OBSAI) has developed a comprehensive set of open specifications for key module interfaces within the base station architecture. This development will enable an open market to become reality.

A key challenge facing cellular operators and other mobile telecommunications service providers in the near future will be the rising cost of the infrastructure needed to provide sufficient capacity for advanced mobile Internet services. Recently launched and forthcoming services such as content download, location based applications, MMS (Multi-media Messaging Service), presence, transactional services and video-streaming, not only add to infrastructure complexity, but will create growth in network traffic (see figure 1). Large numbers of base stations will need to be deployed, initially to provide coverage as next generation mobile technologies come on line, and then to provide sufficient capacity to meet the rising market demand.


OBSAI Base Station Overview

Greater complexity almost invariably leads to higher capital and operational costs. In an increasingly competitive market, mobile operators will not be able to sustain the potential increase in costs that these developments will bring. The cost of base stations and their implementation will also have a critical impact on an operator’s profitability. As next generation networks are deployed and the number of subscribers rises, more and more base stations will be needed to provide the coverage and capacity that the market will demand.

New and more cost-effective ways to design infrastructure equipment must be found in order to reduce the higher costs that would otherwise occur with conventional development methods.

With large numbers of base stations being deployed, even a small improvement in the cost-effectiveness of each BTS can have a large impact on the overall investment that an operator must make.


The Open Base Station Architecture Initiative (OBSAI) is a constantly growing group of over 63 members from industry, spanning leading base station vendors, module and component manufacturers. The members of OBSAI have created a complete set of open specifications for the base station architecture. By defining a basic modular architecture and the detailed specifications for the internal interfaces between modules (see figure 2), OBSAI aims to create an open market for cellular base stations.


har-bus HM Signal- and HM Power connectors

An open market will substantially reduce the development effort and costs that have been traditionally associated with creating new base station product ranges. The availability of off-the-shelf base station modules will enable manufacturers to focus their development efforts on creating further added value within the base station, encouraging greater innovation and more cost-effective products. Furthermore, as product development cycles will be reduced, new base station functions will become available on the market more quickly.

Not only will operators benefit from greater competition among base station vendors, but they will also have the opportunity to bring new and advanced services to market earlier.

End-users will benefit too, by having access to mobile services at the price levels they are prepared to pay and earlier than would otherwise be possible.


OBSAI has now defined a complete set of detailed interface specifications to cover the functions of all key base station modules: control, transport, baseband and radio. The OBSAI architecture provides a clear functional split and detailed internal interface specifications which then allow companies to create modules that are truly compatible in all OBSAI compliant base stations. OBSAI provides the springboard for a new, competitive market for interoperable modules, where economies of scale will result in significantly lower costs.


HARTING has been a supporter member of OBSAI since September 2003.

The company’s activities in the wireless market are in line with those of OBSAI. The OBSAI specifications allow harting the opportunity to support a large group of wireless base station manufacturers and module manufacturers with unified, state of art interconnection solutions. harting has utilised its extensive technology and service capabilities available to provide significant contribution to OBSAI towards the definition of their interconnection specifications.

The har-bus® HM Signal and HM Power connectors meet OBSAI specifications and provide a reliable and cost effective solution for connecting plug-in units to the backplane. The connector solution available from harting will offer full compatibility and intermateability with base station modules.

Kai Nurmenniemi

Application Engineer


HARTING Oy Finnland
Kai Nurmenniemi