PARIS Fabless chip supplier Octasic Inc. is looking to angle its way into the voice-over-packet (VoP) market currently cornered by Texas Instruments Inc.'s DSP-based approach. Octasic's bait: very high-density and low-power specialized chips, marketed to vendors of VoP infrastructure equipment, in an approach that splits voice processing into three branches and devotes a specialized ASIC to each.
"It's tough enough to compete with a giant like TI. My philosophy is that if you must compete, don't go into the fight by using the same weapon your competitor has," said Michel Laurence, chief executive officer of the 60-person Montreal company, which started four years ago as a design house.
With TI touting its DSP-based solution and with Intel Corp., Broadcom Corp. and Centillium Communications Inc. pursuing highly integrated voice-processing chips packed with both DSP and RISC cores, Octasic has looked to conquer by dividing. "There are three technologies you need to own if you are going after the voice-over-IP market: packetization, echo cancellation and compression." Laurence said. "We have developed an extremely efficient and specialized chip for each."
The benefit to OEMs, he said, is that they can build more cost-effective, higher-performance, higher-density equipment using the ASICs than would be possible with approaches that use dozens of general-purpose processors, operating in parallel, to reach the required densities. For ADPCM-based voice compression, for example, "our ASIC, on 1-mm2 silicon, can handle 100 channels, while a DSP of the same size can take only one," Laurence said.
Thousands of voice channels
The VoP market is still in its infancy but will require large volumes of chips, Laurence said, as carriers install very-high-density equipment to support perhaps tens of thousands of voice channels at the network edge and core.
Octasic began life by offering chip design services. Later, it began licensing its packetization intellectual property. The business generated $1.9 million in royalties in 2001.
The company is now entering a third phase as it rolls out VoP coprocessors under its own brand. It recently brought out a family of high-density echo cancellation ASICs.
Octasic's chosen mathematical model for echo cancellation is "least squares" (LS). The theory behind LS, Laurence said, "has been known since the 18th century, but many companies thus far have found it not easy to implement in silicon, especially in a DSP." LS tends to require more memory and processing power than the "least mean squared" (LMS) approach used by most echo cancellers on the market today, Laurence said. But while LMS approximates an echo, LS determines echo characteristics directly, and thus offers more robust echo cancellation, he said.
The ASIC can be used simply as a coprocessor, paired with DSPs designed into VoP gateways or long-distance boxes. Network equipment system designers looking to upgrade their systems or tailor them for different markets are thus spared the task of completely redesigning a box, Laurence said.