Cognitive Radio with Space-Time-Frequency Spectrum Sensing
To date, cognitive radio (CR) has been proposed as the means to promote efficient utilization of the spectrum by exploiting the existence of spectrum holes. Irregardless of the regulatory model, whether licensed, unlicensed, or other new models, these technologies will increasingly allow more intensive and efficient access to, and use of, radio spectrum than possible with traditional, hardware-based radio systems.
Background & Objective: With the rapid growth of wireless communication in the past two decades, there is a vast and growing demand for radio spectrum, and in particular for those frequencies under 3GHz. However, in a recent FCC task force finding, it confirmed that in many bands, spectrum access is a more significant problem than physical scarcity of spectrum. Given the limited spectrum resource and the increasing demand for radio spectrum by the wireless industries, there is an urgent need to improve both the spectrum access and the efficiency of spectrum utilization and one objective of cognitive radio is to fulfill this function.
Technical Discussion: Figure depicted a method known as Space-time-frequency sensing of RF spectrum in cognitive radio. Conventionally, cognitive radio techniques conduct one-dimensional spectrum sensing by periodically scanning only the frequency domain to locate unused frequency bands (spectrum holes). The unused frequency bands can then be used for CR to transmit signals that do not interfere with the signals of other radios. In cooperative spectrum sensing, associated CRs can exchange local sensing results, so that a cognitive network obtains an accurate estimate of unused frequency band, or even, locations of the other radios.
Future Direction: Common goals of a cognitive radio include optimizing throughput to the clients, maximizing reliability, minimizing interference and latency, or doing a combination of these along with other network performance measures.
Contacts:
Koon Hoo Teo
Jinyun Zhang
Technology Area: Digital Communications
Modification Date: July 3, 2007
