MWC: Freescale shrinks the base station down to a chip

One of the key components of Alcatel-Lucent’s (NYSE:ALU) revolutionary new lightRadio architecture announced last week is an indiscriminate chip Freescale Semiconductor unveiled today at Mobile World Congress. It may not look like much, but Freescale has managed to squeeze all of the functions of a base station onto a system-on-a-chip architecture with the rather ungainly name of QorIQ Qonverge.

Gone are all of the discrete elements that the baseband unit at the foot of the cell tower typically contains: the digital signal processor (DSP), the microprocessor brain of the base station and the field-programmable gate array (FPGA) that handles acceleration and higher-order functions. Freescale has built all of those functions into an integrated circuit, which can be used to power any base station from the lowliest femtocell to the largest macro unit.
Base station architectures have become increasingly complex, requiring vendors to source disparate components from specialist manufacturers and then integrate them into a sometimes not-so-neat package, said Lisa Su, senior vice president of Freescale’s Networking and Multimedia Group.

“Usually these technologies come from a lot of different sources and they’re not designed to work together,” Su said. “Several years ago, we came to the conclusion that this was not the most efficient way to build a baseband system.” Su said Freescale started with a simple premise: “This is what a base station needs to be. Let’s design the components specifically for those needs.”

The result was an application-specific integrated circuit (ASIC), but QorIQ “is not your run-of-the-mill chip,” Su said. Freescale has integrated multiple powerful cores onto the same chip, each dedicated to handling the different digital signal and communications processing and baseband and security acceleration functions. Su acknowledges that Freescale isn’t the first company to come up with a base-station-on-chip. Vendors like picoChip for some time have been designing such integrated circuits for small cells dedicated to specific radio technologies. But Su said Freescale is the first to take that concept an extend it to an industrial macro base station, creating a single baseband ASIC that not only can support thousands of users but also all of the major radio interfaces: long-term evolution (LTE), high-speed packet access (HSPA) and CDMA.

The simpler architecture helps to drive down costs. With no discreet components there are no connections between those components, which slow down performance and eke power from the system, Su said. And as integrated circuit stamped into silicon, component costs drop dramatically. “For a current generation base station, we can reduce the cost by a factor of four,” Su said. “We’re talking about reducing the cost of billable materials from the four-digit range down to three digits.”

Alcatel-Lucent is using QorIQ as baseband heart of its lightRadio architecture, which effectively moves baseband processing from the base cell site and into the cloud. In such an implementation, the QorIQ becomes a building block in a virtual baseband implementation. It’s not tied to a specific radio or cell site, but is part of pool of processing resources that can be allocated to any call depending on the current needs of the network. But Su said that QorIQ can also be used in more traditional implementations, sitting in a base station at the bottom of the tower. Freescale has actually created four different levels of QorIQ, designed to fit different sizes of cell deployments.

Femtocell maker Airvana announced today it would be using the smaller two of those chips to power a new line of LTE and multimode LTE/3G femto and picocells. The femto configuration supports eight to 16 users, while the picocell configuration scales up 64 users. In addition to its macro-cell chip, Freescale is also offering a metro/micro-cell configuration, which can support hundreds of users.

Su said Freescale is testing the platform with other vendors and so far the reaction has been very positive. Such a reaction would seem to be contradictory for the big network vendors since part of the value they offer is their ability to integrate these complex components into a base station architecture. But Su said vendors are perfectly willing to let silicon suppliers like Freescale do that integration work for them as their business models evolve.

“They welcome this kind of innovation,” Su said. “The simpler they can make the baseband unit. The faster they can bring infrastructure to market.”