Adaptive self-regulating null navigation in cognitive radio

Abstract

In this paper, we have taken the scenario that cognitive user is fix while the primary user in mobility mode. We capitalize on the power in the direction of the cognitive user and create nulls in the direction of the primary user with self-regulating null navigation technique. When the primary user travel in direction of cognitive user, the cognitive user adaptively regulate the weights and construct null headed for the primary user with notion that, direction of arrivals (DOA) of the primary user are known by cognitive user. When the primary user changes the direction, cognitive user adjusts the complex weights adaptively and creates null toward primary user. In this technique we use the two weights for pair of consecutive antenna elements and attain summer output at different stages. The nulls are generated corresponding to the primary angle and the entire weights are adaptively optimized only reference to angle. When both the primary and the cognitive user revolutionize the direction then all the weights are changes and improve the spectral efficiency of the spectrum with navigating the beam toward cognitive user and bring into being self-generating nulls in direction of primary users. We suppress the interference to primary user by navigating lower power in the direction of primary user and construct the main lobe toward cognitive user. Simulation results established the algorithm effectiveness.