An Adaptive Transmission Scheme for Cognitive Radio Systems Based on Interference Temperature Model

We present an adaptive transmission scheme for the CR (cognitive radio) systems. The proposed scheme estimates the distance between a CR user and an incumbent user utilizing IT (interference temperature) information recognized through the spectrum sensing procedure. Then, the CR user determines the maximum transmission power which does not cause any interference to the incumbent user by using CR-APC (CR-adaptive power control). At the same time, in order to provide the maximum throughput to the CR user, the proposed scheme adaptively selects the modulation order considering the determined transmission power and the IT value by applying CR-AMC (CR-adaptive modulation and coding) in the given channel state. Hence, wireless communication equipments using the proposed scheme are able to adaptively transmit the data without interference on the incumbent users in various channel environments.