Peak to average power ratio (PAPR) reduction of OFDM signals has extensively been studied in the literature. Tone Reservation (TR) is one of the most famous algorithms and has already been included in some digital television standards such as DVB-T2 and ASTC3.0. However, the literature is still lacking theoretical analysis and performance bounds for the PAPR reduction of OFDM signals, especially using TR algorithms. For the first time, this paper provides fundamental results establishing the links between TR-PAPR reduction and the remaining signal distortions at the output of a non-linear high power amplifier (HPA) with and without memory effects. We first derive a generic EVM expression relying on the statistical characteristics of the samples composing the time domain signal and for any PAPR reduction technique. Computing these moments in the case of the quadratically constrained quadratic problem (QCQP) algorithm known as the optimal solution to the TR-PAPR reduction problem allows us to get the lower bound of the EVM of OFDM signals after TR-PAPR reduction and nonlinear HPA. As a reference, we also provide the EVM expression using a clipping-based PAPR reduction method. The obtained EVM expressions have direct practical meaning since they are in function of the input power back-off (IBO) applied to the signal before the HPA. They also consist in a general analytical framework for OFDM PAPR reduction since they can be further exploited to analyze the performance of sub-optimal TR-based PAPR reduction algorithms.
Abstract-In this paper, the performance of multi-user (MU) massive multiple-input multiple-output (MIMO) systems is evaluated in terms of bit error rate (BER). We focus on the case of a downlink single-cell scenario with linear precoding as zero forcing (ZF) and conjugate beamforming (CB). This performance evaluation is done over a statistical mmWave 5G propagation channel, using NYUSIM channel simulator developed by New York University in 2015. A study of the channel response characteristics is provided to define the system parameters. Simulation results in single-user scenario show better performance with an increasing number of base station antennas due to the increase of system diversity. For multi-user scenario, the performance degrade for a higher number of cell users due to inter-user interference.Index Terms-Massive multi-user MIMO, 5G mmWave propagation, frequency selective channel, OFDM
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