Experience cooperative sharing in cross-layer cognitive radio for real-time multimedia communication

The central problem in cognitive radio (CR) is how to adapt, given a wireless environment, so as to operate while meeting the constraints of a primary incumbent in a spectrum band. Adaptation for transmission of real-time multimedia lends itself to a cross-layer approach. This paper discusses a cross- layer CR scheme for real-time multimedia transmission that jointly adapt transmit bit rate and source-channel coding when sharing the spectrum with a primary network through DS-CDMA. While a cross-layer approach results in a notable reduction in distortion and congestion rate, it increases the complexity of the algorithm. This issue is addressed by introducing a novel cross-layer cooperative scheme that with- out performance loss reduces by as much as thirty times the number of iterations needed to achieve convergence by the cognitive algorithm. This scheme extends to a cross-layer setting, the docitive paradigm, by having secondary nodes share with a newcomer node their learned awareness of the environment and the associated results for actions.