Cognitive Radio Using Multi-transmission Links: A novel approach effective in metropolitan areas

Although the definition of cognitive radio is still being discussed by IEEE P1900 and other organizations, the objective of cognitive radio addresses improvements in frequency utilization, flexible selection of optimal frequency bands, wireless channel bandwidth, modulation schemes, and access methods. In metropolitan areas, a huge number of wireless stations consume a variety of frequency bands. In such a radio environment, it is difficult to continuously utilize DSA (Dynamic Spectrum Access) because of the lack of vacant areas for secondary usage. Although if a wireless station feeds its transmission data to the wireless system with the largest margin of capability packet-by-packet, it effectively utilizes the "white space" and improves the performance of all wireless connections. The cognitive radio system proposed in this paper has the advantage of implementing existing wireless technologies within the current wireless regulations. This paper introduces cognitive radio using multi-transmission methods and its implementation. The estimated method of defining the margin of the wireless system second-by-second also addresses the universal index for various wireless systems.