In attempt to apply order to an increasingly fractured technology, the femtocell community has agreed to lay down a single standard for the interfaces between elements in the femtocell architecture, a move intended to make any femtocell compatible with any network. What exactly that standard will be hasn’t yet been decided. The Femto Forum is taking it one step at a time.

The Femto Forum, a group of global equipment and software vendors and operators, today announced its membership has agreed to develop a femtocell framework that will have a single standard interface between femtocell base station and network gateway and use already defined standards to interface between gateway and core network.

Femto Forum chairman Simon Saunders said the effort has been primarily carrier driven. “They really love the idea of femtocells, but it is really important to them to support femtos from multiple suppliers,” Saunders said. “In order to support four or five different femotocells in the network, they obviously don’t want to have a gateway for every vendor.”

In addition, the Forum has laid out specifications for the femtocells themselves. It a smart client architecture that incorporates many of the signaling and management functions of the radio network controller (RNC) and base station controller (BSC) in UMTS and CDMA femtocells, thus taking the burden of managing thousands of individual femtocells off of the carrier’s macro network and reducing the signaling traffic to the gateway.

Saunders said that the Forum said that centralizing intelligence in the femtocell ultimately doesn’t add too much cost to the femtocell, but it minimizes signaling bottlenecks over the broadband connection used to backhaul the femtocell. In country’s like the U.S., where home broadband connections have megabits of capacity, signaling overhead might not be a problem, but Saunders said the Forum is targeting the broadest use cases for femtocells it can. “In some places broadband can mean as little as 200 kb/s in an ADSL uplink,” he said. “With this architecture we can still support 4 simultaneous phone calls over that connection.”

No specific standard has been set, but Saunders pointed out that all of the competing interfaces being used--whether unlicensed mobile access being promoted by Kineto, the session initiation protocol (SIP) backed by IMS vendors or the IuB interfaces championed by Nokia Siemens Networks—will fully meet the guidelines laid down by the Femto Forum. The Forum now plans to develop the nuts and bolts of the protocols and architecture and then submit them the wireless standards bodies governing UMTS and CDMA, the 3GPP and the 3GPP2, and eventually to the WiMAX Forum.

It will be too late for the current planned femtocell deployments as the Forum still has work to do, Saunders said, but future networks will be able to fully take advantage of the standards. “Operators are happy to deploy things that are slightly proprietary today if open standards are on the roadmap,” he said.

In other femtocell news, Qualcomm has invested in femtocell maker IP.Access, which is currently the hottest company in the femtocell market. Cisco Systems and Intel have both taken stakes in the IP.Access, which several news reports have pegged as the supplier for a future AT&T femtocell deployment.

PicoChip also today announced it has developed reference designs for pico and femtocells for future Long Term Evolution (LTE) networks, an unlikely accomplishment considering the LTE standard has not been fully approved by the 3GPP. Many vendors though, have been releasing LTE products they claim will be fully complaint with the standard once passed in an effort to get an advantage in future trials and contracts.