Startup seeks to encapsulate RF intellectual property

Startup seeks to encapsulate RF intellectual property
By Peter Clarke, EE Times
March 8, 2001 (12:55 p.m. EST)
URL: http://www.eetimes.com/story/OEG20010307S0030

LONDON — RF Engines Ltd., a startup on England's Isle of Wight, is attempting to take algorithmic approaches to digital signal processing, rendering them as compact hardware designs. The company claims it can process wideband signals in real-time, outperforming many other hardware implementations and software running on a general-purpose DSP.

RF Engines has a specific algorithmic architecture, called pipelined frequency transform (PFT), for the signal analysis of ultrawideband signals. The company intends to license this and other radio frequency intellectual-property (IP) cores to OEMs and semiconductor companies.

According to RF Engines (Newport, England), applications could include cellular and satellite communications, broadcast systems, test and measurement instrumentation, and weapon systems.

The PFT, like a fast Fourier transform (FFT), can be used to transform signals from the time domain to the frequency domain. Unlike an FFT, the PFT can retain high accuracy in hundreds of channels and add high-performance filtering, said John Lillington, the company's chief executive, chief technology officer and founder.

"The FFT has relatively poor filter performance," said Lillington. Although it would be possible to add filters on a per-channel basis, that would require considerable additional silicon complexity — something not necessary with the PFT, Lillington said. Similarly, running such FFT routines and filters on a general-purpose DSP would prevent the possibility of extracting and outputting the channels in real-time, he said.

A demonstration based on an implementation of the PFT pipelined across four Xilinx FPGAs can handle an 80-MHz bandwidth signal on a 200-MHz carrier at 8-bit resolution and extract up to 1,024 channels with sharp channel filter characteristics, Lillington claimed.

Lillington declined to give more details about the PFT, but said in the channel-extraction appli cation it is based on the successive splitting of signal information, and is an implementation of known mathematical methods of signal transformation.

Lillington said his approach could be applied to cellular communication basestations, satellite communications, orthogonal frequency division multiplexing systems such as digital audio and digital television broadcasting, radar and software-defined radio systems.

"Basically, the broader the bandwidth the more applicable our techniques," said Lillington.

RF engines are unlikely to be appropriate for single-channel Global System for Mobile Communications or second-generation handset transceiver applications. However, in basestations where hundreds of signals need to be extracted, Lillington said the approach could pay off in reduced hardware costs. In future multimode handsets and software-driven radio sections, the PFT could also be used, he said.

Lillington said that the company is looking to work with partners to implement the PFT and other d igital RF cores in ASIC technology, where they could be even more efficient in silicon area and power.

"But the FPGA approach is valid. The reconfigurability is a useful attribute in some circumstances. There's an awful lot of FPGAs being used in basestations," said Lillington.