During the past few years, cognitive radio networks (CRNs) have emerged as a solution for the problems created due to fixed spectrum allocation such as inefficient usage of licensed spectrum. CRNs aim at solving this problem by exploiting the spectrum holes (the spectrum not being used by primary radio nodes at a particular time) and allocating the spectrum dynamically. In this paper, we address the problem of dynamic channel assignment for cognitive radio users in multi-radio multichannel cognitive radio networks (MRMC-CRNs). We propose an efficient spectrum-aware dynamic channel assignment (SA-DCA) strategy for such networks. SA-DCA utilizes available channels and assigns them to multiple radio interfaces of cognitive radio nodes based on primary radio unoccupancy, minimum interference to primary radio nodes, maximum connectivity and minimum interference between cognitive radio nodes. We perform simulations in NS-2 and compare the performance of SA-DCA with two related strategies. Simulation results show that SA-DCA assigns channels efficiently and results in significantly reduced interference to primary radio nodes and increased packet delivery ratio in MRMC-CRNs.
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