Vanu is applying its software-defined radio techniques to the problem of network sharing, announcing today a new cell-site architecture that allows multiple “virtual” base stations to co-exist in the same box. Called MultiRAN, the architecture lets multiple operators run their networks not just at the same cell site but off of the same infrastructure.

Operators in western Europe have already begun experimenting with shared networks using standard UMTS gear, but those efforts haven’t resulted in completely compartmentalized networks in which individual operators retain operational control, said Jeff Steinheider, Vanu senior product manager. “By applying virtualization to the network, everyone has their own BTS [Base Transceiver Station],” he said. While a shared UMTS network would be akin to sharing an apartment with a roommate, using Vanu’s solution would be the equivalent of the living in a duplex. The duplex’s other residents may share the property, the structure and certain amenities, but each individual unit is walled off privately from the others.

Network sharing isn’t in high demand in North America, where carriers still use network planning and coverage to differentiate themselves. But in developing markets, the high costs of deploying a network and the low revenue per subscriber force carriers to seek capex and operational savings wherever they can. Vanu unveiled the solution today at an Indian telecom trade show in Delhi, where it expects its first customers to be. But Steinheider said that as price pressures increase in developed markets, operators there may start considering network sharing as well, especially as they expand into low-density markets they would traditionally serve through roaming agreements. A hosted network business model would then emerge, in which a third-party such as a tower provider would deploy the infrastructure and then sell base station slots to operators, Steinheider said. Currently MultiRAN can support four operators on a single unit.

“I think this is a logical extension of consolidation trends we’ve seen with towers,” Steinheider said. “We’re moving from consolidating the physical plant to the active electronics.”

MultiRAN only supports GSM currently, and each operator must be assigned a separate channel or channels of spectrum. Other resources such as antennas and backhaul are shared between them, but each operator maintains a separate radio network controller to manage their virtual network.

Vanu has applied its SDR technology to multi-platform solutions as well as multi-carrier platforms. Its first product was a software base station that could support CDMA and GSM simultaneously, allowing operators using both network technologies to deploy a unified solution. The platform is mainly targeted at North American rural operators that make a good deal of their revenue from roaming, as they could service both CDMA and GSM carriers on the same infrastructure.