One-Chip Radio/Baseband IC Handles Cognitive Radio

A combined single-chip radio and baseband processor, the RTU7010, has demonstrated its ability to operate in an ultra-wideband (UWB) cognitive radio system, according to Realtek Semiconductor Corp. The RTU7010 implements all communications-related modes, both mandatory and optional, of the WiMedia PHY 1.1 standard in the 3.168- to 4.752-GHz band. These include eight data rates, from 53.3 to 480 Mbits/s, and all fixed-frequency and frequency-hopped channels, along with many proprietary detect-and-avoid features for managing coexistence with other wireless technologies. The device also supports the standardized WiMedia MAC-PHY Interface. The chip integrates a digital baseband processor with two full radio chains, along with the circuitry for optimal combination of the two radio inputs. It comes in a 7- by 7-mm package.

Realtek’s cognitive-radio functionality complies with the spectrum-avoidance requirements that will apply in several worldwide regulatory domains beginning in 2009. The requirements ensure satisfactory coexistence of UWB devices with other wireless services. The UWB transmitter responds to the presence of a protected service in its immediate vicinity by transmitting at a greatly reduced power level in a narrow band centered around the protected service. By tailoring the location and width of the spectral notch, interference-free coexistence with other services is ensured. The RTU7010 reduces the power-spectral density around the protected service to below −70 dBm/MHz, while maintaining the maximum regulated limit of −41.3 dBm/MHz elsewhere. This represents approximately a thousand-fold reduction in transmitted power around the protected service and meets the suppression level that will be required by regulators in Japan and Korea beginning in 2009 for devices operating in the 4.2- to 4.8-GHz band.