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چکیده
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In this paper, a novel scheme is proposed in which mobile users organize a virtual multiple-input single-output (MISO) structure with the aid of relaying based on device to device (D2D) communication in a 5G cellular network. The performance of distributed quasi-orthogonal space–time code (DQOSTC) based virtual MISO for the cooperation among four communication nodes is investigated. Error propagation in the second hop of relaying in decode and forward (DF) relaying protocols, is one of the main challenges of virtual MISO systems and it can be mitigated by the joint use of selection relaying and beamforming techniques. We propose a novel beamforming technique for removing the end to end inter-symbol interference (ISI) of D-QOSTC scheme. By means of our proposed scheme, even though we have error propagation in the second hop of relaying, without any loss in bandwidth or rate, the full diversity order can be achieved. Moreover, the performance of bit error rate (BER) with closed form result is analyzed and compared to the simulation results. The results exhibit that the theoretical BER curves coincide with the simulation ones and the system achieves full diversity order. The simulation results also indicate a significant gain in power efficiency for the optimal selection relaying and fixed relaying compared to conventional schemes.
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