hybridprecoding, combining the digital and analogue precoding, is a key enabler to reach a compromise between system performance and hardware complexity in millimetre wave (mmWave) massive multiple-input multiple-out...
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hybridprecoding, combining the digital and analogue precoding, is a key enabler to reach a compromise between system performance and hardware complexity in millimetre wave (mmWave) massive multiple-input multiple-output (MIMO) systems. Most previous studies on hybridprecoding considered narrowband channels. However, mmWave systems are expected to operate on wideband channels with frequency selectivity. In this study, the authors focus on the hybridprecoding design in mmWave massive MIMO systems using orthogonal frequency division multiplexing (OFDM). By transforming the hybridprecoding problem into a series of sub-problems, they propose a low-complexity algorithm to design the digital precoder and analogue precoder alternately. In particular, a phase pursuit method is introduced to seek this solution of analogue precoding matrix with the constant amplitude constraint. Simulation results and complexity evaluations reveal that the proposed algorithm can obtain better performance and lower complexity than some existing solutions in mmWave OFDM systems.
In this study, the performances of commonly used precoding schemes are evaluated based on channel measurements carried out at 28GHz in a railway station for a massive antenna system configuration. And a hybrid precodi...
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In this study, the performances of commonly used precoding schemes are evaluated based on channel measurements carried out at 28GHz in a railway station for a massive antenna system configuration. And a hybrid precoding algorithm for a fifth generation (5G) multi-user antenna system is proposed and its performance is evaluated based on real measured channels. Specifically, An upper bound for achievable sum-rate of phased zero forcing (PZF) algorithm is derived and a precoding technique by reduction of phase shifters (PSs) named reduced-PZF (RPZF) is proposed, which can obviously reduce power consumption in hybridprecoding systems. In addition, the authors give the closed-form expression for achievable sum-rate when RPZF is used. There are no requirements in the authors' proposed scheme with complicated matrix decomposition and optimisation techniques. The simulation results show that it is possible to reduce 30 and 50% of the PSs by using the proposed hybrid precoder with better system performance in the line-of-sight (LoS) and non-LoS scenarios, respectively. In addition, the digital PSs with 3 bits low resolution can achieve the similar performance when using analogue ones.
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