tailieunhanh - Theory of the radio channels

The cognitive radio paradigm is based on the ability of sensing the radio environment in order to make informed decisions. This paper describes the effects of sensing on the cognitive radio channels capacity region. Sensing is modeled as a compression channel, which results in partial knowledge of the primary messages at the cognitive transmitter. This model enables to impose constraints on the sensing strategy. First, the dirty paper channel capacity is derived when the channel encoder knows partially the side information. Then, the capacity area of the Gaussian cognitive channel with partial information is derived. Finally, numerical results illustrate the. | Theory of the radio channels Theory of the radio channels Van Due Nguyen 4 Back ground of stastistical theory Definition of autocorrelation function of a stochastic process Ä r x r r Van Due Nguyen 3 Motivation îî-îf The channel determines System resources total bandwidth carrier frequency transmitted power etc. Scenario architecture Services which can be offered voice video data rate etc. Complexity and quality of the system. Channel modeling is the first task for any system design Van Due .