Massive MIMO system has been introduced as a promising technology in achieving the benefits of the fifth generation of wireless communications, including high spectral and energy efficiencies. Having an accurate channel estimation is the main challenge for the utilization of the benefits of this system. Pilot contamination causes errors in user channel estimation and is a serious obstacle to access the benefits of the Massive MIMO system. In order to eliminate the destructive effect of the pilot contamination and to track the temporal variation of the users’ channels (due to displacement) in the Gauss-Markov channel model, an adaptive smart pilot allocation method in uplink TDD (Time Division Duplex) mode is proposed. Moreover, by using the virtual channel modeling technique, an alternative solution for calculating virtual assignment cost equivalent to the actual allocation cost in each block is presented in an adaptive manner which has low computational complexity. Finally, the performance of the proposed adaptive pilot sequence allocation algorithm is evaluated using computer simulation. Our results demonstrate the good performance and fast convergence of the proposed algorithm under different users' speeds.

Keywords: Massive MIMO System, 5G wireless communication system, Pilot Contamination, Smart Pilot Sequence Allocation, Adaptive algorithm.

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