OPTIMAL IPW ALGORITHM IN OFDM-BASED COGNITIVE RADIO SYSTEMS
The optimal of Interactive Partitioned Water-filling (IPW) algorithm is applied in the power distribution in cognitive radio systems based on orthogonal frequency division multiplexing (OFDM) with the aim at optimizing channel capacity for systems by considering total constraints of channel power, and capacity constraints in each subchannel. Leakage power in sub-carriers adjacent to special attention while limiting the power of major primary user (PU) and the establishment of protection of spectrum bands for the primary user and spectrum of secondary user (SU) is very strict. Optimizing IPW algorithm is performed repeatedly in the sub-channels in which the capacity is limited strictly and are implemented form of steps for the sub-carriers. The results from simulation to propose algorithm showed not only better steps for the IPW algorithm, but also for simpler complexity of calculations.