Make the most out of spectrum allocation

Spectrum for the wireless market is like waterfront property. It’s exceedingly scarce and expensive, but everyone wants some.

The key is to find high-spectral efficiency for low cost, said Laurie Wallace, director of strategic marketing for PMC-Sierra Inc. of Burnaby, B.C. In an effort to capitalize on the second generation and the up-and-coming third generation (3G) cellular PCS wireless markets, PMC-Sierra launched the PM7815 PALADIN-15, an enhanced version of its PALADIN Digital Signal Processor controlled power amplifier architecture for wireless infrastructure equipment.

“We recognize the fact that spectral efficiency is fundamentally limited by the distortion in the transmitter,” Wallace said. “Both the transmitter and the amplifier are highly non-linear, so we have to find ways to clean up that distortion to get maximum spectral efficiency.” At the same time, power efficiency is just as critical, he said.

The PALADIN-15 chip design supports 15MHz WCDMA and cdma2000 applications and, according to the company, eliminates transmitter distortions and improves spectral efficiency in wireless base transceiver stations (BTS) at lower power and lower cost than other technologies.

“The power efficiency issues become critical in areas like Japan, where the government has recognized the fact that wireless base stations are the biggest drawer and user of power,” Wallace said. “Therefore, power efficiency is a major issue because they don’t want to have to be able to build a nuclear power plant every time somebody builds another major network.”

Wallace said the PALADIN-15 would save approximately 15 megawatts of power per year in a typical wireless network of 10,000 BTSes. In dollar terms, that adds up to a savings of about $20 million annually.

While an unspecified number of test versions of the PALADIN-15 have been shipped to customers, the firmware for the chip design has not yet been completed, Wallace said.

“We’re able to handle multi-carrier transmit technology, meaning, in this case, up to 15MHz of instantaneous bandwidth. That would allow three carriers to be transmitted instantaneously through our system,” Wallace said. He added that spectrums are being allocated the world over, yet few carriers get more than 15MHz to use, so it’s necessary to maximize what spectrum they do have.

Stan Bruederle, a chief analyst with Stamford, Conn.-based Gartner Dataquest, describes the PMC-Sierra approach to the market as “unique.”

“It allows the base station system designers to put it on their transceiver card and change the power amplifiers they have to use to support the WCDMA standard requirements because the bandwidth available for the third generation standards is 15MHz,” Bruederle said.

The biggest benefit to using the PALADIN-15 chip design is the tremendous cost savings PMC-Sierra says it can create, Bruederle said. He added that current technologies often cost about US$100 per watt, and PMC-Sierra’s product costs much less.

PMC-Sierra’s PM7815 PALADIN-15 will be available in October. According to the company, it will be priced at US$375 in 10K quantities. PMC-Sierra can be found on the Web at