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Reducing the jamming effects in multicellular Massive MIMO systems

As Massive multiple‐input multiple‐output (Ma‐MIMO) is one of the critical 5G technologies, security aspects of this technology in terms of powerful distributive jamming attacks for improving the total system performance are so important. In this paper, we evaluate the sum spectral efficiency (SE) of Ma‐MIMO systems in the multicell scenario concerning jamming effects. First, the closed‐form expression for sum SE using two detectors maximum ratio combining (MRC) and zero‐forcing (ZF) in the presence of a jammer was obtained. Next, the effects of jamming power, the number of base station antennas, the signal‐to‐noise ratio (SNR), and coherence block lengths on the system performance were obtained. Finally, to improve the signal‐to‐noise and interference ratio (SINR) of cell edge users, the problem of optimizing the fairness trade‐off between the central legitimate users and the cell edge legitimate users is modeled by using log barrier functions. We propose an alternating algorithm to solve the non‐convex problem. Numerical results showed that by considering the same interference power and the power of the legitimate users, the sum SE improved with proposed schemes and also by increasing the number of antennas at BS. Also, the ZF outperforms MRC with increasing the number of antennas. Finally, it is shown that by using the optimal legitimate users instead of overall legitimate users, the system performance in terms of fairness sum SE trade‐off improved.