NSN releases multi-radio base station

Nokia Siemens Networks today unveiled the latest version of its Flexi software-defined radio base station, which supports 2G, 3G and eventually 4G technologies on the same module. NSN officials said though the software necessary to upgrade the Flexi to long-term evolution (LTE) isn’t yet ready, the new architecture will allow carriers to deploy GSM/EDGE and high-speed packet access (HSPA) networks, knowing that the equipment can be reconfigured for LTE in the future.

NSN announced at Mobile World Congress last year a multimode version of its UMTS Flexi that would also support the future LTE upgrade, but this new release has some key differences, said Bryan Boudreaux, NSN’s head of LTE solutions. The Multiradio Flexi supports three generations of wireless technology concurrently. Making use of dedicated 70-watt power amplifiers, the base station module’s three sectors could run GSM, HSPA and LTE simultaneously, though Boudreaux said that the scenario is unlikely. What’s more plausible, he said, is an operator deploying GSM or UMTS in a market today and migrating that network to LTE in the future, either as a whole or sector by sector, allowing the operator to gradually transition to a 4G network.

“Operators want a product that will adapt to them; they don’t want to adapt to the product,” Boudreaux said.

The new Flexi’s multi-radio support only works when all radios are the same frequency band, however, meaning an operator running separate networks on separate spectrum wouldn’t be able to use a single module to support them. But for operators looking to reuse GSM sites for 3G or 4G, the solution may be optimal. T-Mobile USA, for instance, has built its 3G network on the Advanced Wireless Services (AWS) band but plans to use its PCS spectrum for LTE once it begins migrating GSM voice customers to the 3G network. Using such a multi-radio solution, T-Mobile could run GSM and LTE simultaneously at 1900 MHz. While AT&T is targeting 700 MHz for LTE, it runs both its 2G and 3G networks over 1900 PCS. Operators both domestic and abroad are considering repurposing their cellular spectrum for UMTS or even LTE.

The multi-radio Flexi won’t be available for commercial shipments until 2010, by which time the LTE standard should be finalized and most vendors will have their LTE software and equipment ready. NSN recently won a contract with Telus and Bell Mobility to build their joint UMTS network, which the two Canadian operators plan to upgrade to LTE. The multiradio Flexi would be optimal for such deployment, since the operators are building both 3G and 4G networks from scratch, most likely over their new AWS spectrum. But the multi-radio won’t be ready in time for Telus’s and Bell’s initial rollouts. NSN officials said they will be supplying the multimode HSPA version instead, which will support a direct upgrade to LTE.

NSN also gave a sneak peak at its multi-controller platform, which combines the functions of the GSM network’s base station controller (BSC) and the UMTS networks radio network controller (RNC). NSN said the platform is designed to scale to adapt to the massive growth in both subscriber and overall traffic growth, a single controller supporting the 35 Gb/s of capacity. The controller isn’t being targeted at LTE networks, though, as the evolved packet core service architecture evolution (SAE) collapses the functions of the network controller into the base station.