Cognitive Radio and advanced spectrum management

摘要

Spectrum access, efficiency, and reliability have become critical public policy issues. Recent study by FCC Spectrum-Policy Task Force (SPTF) found that while the available spectrum becomes increasingly scarce, the assigned spectrum is significantly underutilized. The term Cognitive Radio was first defined by Mitola in 1999. Cognitive radio is a novel technology, which improves the spectrum utilization by seeking and opportunistically utilizing radio resources in time, frequency and space domains on a real time basis. It refers to a new type of radio hat uses real-time interaction with its environment to determine transmitter parameters such as frequency, power, and modulation. The cognitive radio technology poses many new technical challenges, and overcoming these issues becomes even more challenging due to non-uniform spectrum and other radio resource allocation policies, economic considerations, the inherent transmission impairments of wireless links and user mobility. Cognitive radio technology advances are based on interdisciplinary research, including among others: signal processing, information theory, communications engineering, artificial intelligence, game theory and economics. Many case studies and examples will be investigated i.e. ultra-wide bandwidth technology as a transmission technique suitable for implementing a cognitive radio system, and a comparable measurement of TV spectrum band in an urban environment is another example.