Polyphase magnitude modulation (MM) has been shown to be a robust and effortless mean to improve the efficiency of a transmitter's high power amplifier (HPA), due to the real-time reduction of the peak to average power ratio (PAPR). MM's technique flexibility allows us to include the MM system on any existing single-carrier (SC) based transmission system with clear benefits on the achieved bit error rate emph{vs} overall signal power to noise ratio. This paper analyzes the efficiency of MM when added to a multi- input multi-output (MIMO) system, using a block-based SC transmission combined with iterative block decision feedback equalization (IB-DFE). To improve the IB-DFE performance for low power signals, we consider an additional scheme where low-density parity-check (LDPC) coding and turbo equalization are added. Simulation results show a net power efficiency enhancement, particularly for systems with channel coding, confirming MM as a major asset for high performance communication systems.

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