By Patrick Mannion, EE Times

Wireless-chip startup Provigent Inc. is aiming to lower the cost of establishing a point-to-point broadband wireless connection with the PVG310, a single-chip modem that uses cross-polarization interface cancellation (XPIC) technology to double channel capacity. The chip will allow an operator to maximize the throughput of a given channel and either increase the dollars that channel generates or halve the amount of licensed spectrum needed to support it.

Mostly used for cellular backhaul, fixed wireless transmission systems or private wireless networks, wireless point-to-point systems account for nearly $3.5 billion in annual equipment sales, according to figures from Provigent (Los Altos, Calif.). That's about $1 billion more than Wi-Fi and an order of magnitude more than the WiMax market, the company said. Despite the market's size, "The gross margins of systems are really going down," said Ran Soffer, director of marketing. Cutthroat pricing and constant pressure to improve performance mean "150 or so vendors must still develop their own equipment in-house, so there's no economy of scale."

The economics would improve if the industry settled on an integrated baseband modem with the processing power and flexibility to handle a variety of modulation and error-correction schemes and very high data rates, Soffer said. Now generally available, the PVG310 chip handles payload rates of up to 322 Mbits/second, which can be doubled to 622 Mbits/s using XPIC, in which two streams are transmitted simultaneously in the same frequency band, but orthogonally to each other. "This doubles capacity so you can save on spectrum-licensing fees," Soffer said. The transmission rate translates to 13.5 bits/Hz, or "five times greater than common solutions to date," he said.

The PVG310 includes support for QPSK as well as 16- to 256-QAM modulation, a maximum bandwidth of 56 MHz, flexible error-correction capability, intermediate-frequency or baseband sampling, and I/Q imbalance correction. All functions are implemented digitally, eliminating the need for an external voltage-controlled oscillator and loop filters.