Feasibility of a Cognitive Extension to Existing 802.11b Wireless Devices
W. Justin Barnes · SHAREOK (University of Oklahoma; Oklahoma State University; Central Oklahoma University) · 2009
Cognitive radio presents a means of altering the communication method of a wireless device based on channel conditions and the intended receiving device. However, the design of such a radio is very complicated as it must consider the possibility of multiple forms of modulation, differing transmit frequencies and symbol rates, and the accompany changes to other training procedures such as synchronization. This work proposes that in some cases a simpler, more cost-effective approach can be taken, that builds upon the architecture of existing wireless devices forming a new radio with cognitive capabilities. This approach allows the base device to perform all baseband and MAC-related functions with minimal or no negative effects due to the extension. As changes in modulation type are much more complex, the analysis in this work is restricted to systems wanting to intelligently alter their transmit frequency or power, such as the 802.22 standard. Because of the extensive investment that has already been made in 802.11 technology, 802.11b chipsets and APs are very inexpensive. Therefore a frequency conversion extension was designed and tested as the fixed architecture to enable signal conversion of an 802.11b signal. Cognitive functionalities could be added with little modification to the proposed design in this work.