Freescale prepares next-generation DSPs for 4G

Freescale Semiconductor unveiled a new digital signal processor (DSP) it is positioning as the future workhorse for Long Term Evolution (LTE) and other next-generation 3G and 4G networks. The company has essentially applied six cores to a single shrunken-down chip, which it claims will be the highest performing programmable DSP on the market, optimal for the heavy data rates of LTE.

DSPs are specialized microprocessors that perform the heavy mathematical number-crunching on the wireless signals in a wireless base station. As wireless technologies become more efficient, supporting higher bit rates and broader channels, the workload on a DSP increases dramatically, thus requiring more powerful processing capabilities for each wireless generation. Over the years, Freescale, Texas Instruments and other DSP manufacturers have met these growing capacity demands by creating multicore processors, more sophisticated on-board operating systems and utilizing ever-smaller silicon processes.

The new platform, given the not-so-catchy moniker MSC8156, expands Freescale’s previous four-core chips to six cores, greatly increasing their processing power, while simultaneously shrinking their overall footprint 75% by going to a 45-nanometer silicon process from a 90-nm process, which not only increases performance but also cuts power requirements in half. Overall, the MSC8156 delivers twice the performance of Freescale’s current high-performance DSP, the MSC8144, said Randy Clark, DSP portfolio manager for Freescale.

Newer 3G radio technologies such as evolved high-speed packet access (HSPA+), which greatly increases HSPA’s speeds through the addition of higher order modulation and smart antennas, can easily benefit from the new DSP’s capabilities, Clark said, but the platform will truly shine as the industry moves from CDMA to orthogonal frequency division multiplexing access (OFDMA) technologies such as LTE and WiMAX. OFDMA not only packs more bits into hertz of spectrum, increasing DSP demands, it also supports expansive channel sizes, doubling or quadrupling the signals the DSP has to process. Freescale is billing the new six-core DSP as an LTE carrier on a chip, supporting an entire 20 MHz LTE channel on its lonesome.

Freescale is timing the DSP’s release to coincide with the ramp-up in LTE deployments. Most operators have targeted 2010 or after for the commercial launch of their LTE networks, so Freescale plans to start sampling the chip in 2009 and shipping it in volumes to vendor partners in 2010. Vendors, however, are releasing their initial LTE product lines next year. While Freescale’s new platform may miss the launch of those first base stations to roll out of the factories, Clark said, vendors can stack its current-generation DSPs to achieve the performance necessary for initial LTE infrastructure. As commercial production ramps up in 2010 and 2011, though, the MSC8156 will be ready for mass-scale deployments, he said.