IMPROVEMENT OF CHANNEL CAPACITY IN COGNITIVE RADIO SYSTEMS BASED ON OFDM
The spectrum-sharing access model in the cognitive radio system consists of two main models, the Overlay model and the Underlay model. In this paper, a power overlay scenario based on the overlay model is proposed based on the traditional Iterative Partitioned Water-filling (IPW) algorithm. This scenario applies to protected and reasonably allocated bandwidth between sub-channels where the Primary User (PU) and the Secondary User (SU) are placed adjacent. This scenario not only maximizes the user capacity of the secondary SU, but also reduces the power leakage of sub-carrier users of the PU
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