Radio three-chip set for basestations enables active antennas

June 06, 2012 // By Rick Merritt
Unitrx from PMC-Sierra is a three-chip set for base station radios geared to break through mobile network congestion by enabling active antennas. The chips replace as many as 14 discrete devices used in traditional basestation radios.

Up to four Unitrx chip-sets can be linked to support 8x8 multiple input, multiple output (MIMO) antennas. The extra transmit and receive channels let carriers spread coverage to broader areas and more users than conventional designs.

Carriers are driving power dissipation of base stations from 60 W today to as much as 80 W in some trials to extend their range. “We think smart antennas with MIMO are a better approach to brute force increasing power,” said Robert Chow, director of product marketing in PMC’s broadband wireless division.

Active antennas will be used in tandem with a new tier of small cell base stations carriers are also testing as a way to extend the coverage of back-haul networks clogged with mobile data. Carriers are still defining just what mix of active antennas and small cells carriers they will support in their next-generation nets.

“That’s a billion dollar question,” said Chow. “There’s lots of development at the equipment level and parallel development in software enabling these components to work cohesively in a real network,” he added.

The three Unitrix chips for basestation antennas consume 8.1 W and 2,900 mm 2 in area compared to as much as 17.6 W and 6,200 mm 2 for the 14 discretes they replace, PMC said. The company had a background in converters, serdes and other telecom components used to create the new chips.

The chip set covers frequencies from 400 MHz to 4 GHz to support everything from GSM 2G to LTE 4G networks. The chips include separate transmitter and receiver chips and a clock synthesizer.