The Effection Of 5G Millimeter Wave RF Hardware On Waveforms

The millimeter wave band will provide a larger bandwidth and higher data rate to meet the needs of multiple application scenarios and emerging services in the Fifth Generation Mobile Communication(5G).The new air interface has become a research hotspot in 5G millimeter wave(mmWave)communication.The impact of millimeterwave RF hardware impairments on system performance cannot be ignored.This thesis combines four kinds of waveforms which are currently studied in the industry with three kinds of mmWave RF hardware impairments,studies the influence of mmWave RF hardware impairments on waveform performance,and compensates mmWave RF hardware impairments.Comparing the performance of the waveform before and after mmWave RF hardware impairments compensation,combining with waveform computational complexity and other evaluation indicators,a waveform which is more suitable for the 5G mmWave communication will be selected in this thesis.Finally,a fixed-point simulation of that waveform will be implemented in this thesis,based on the system performance and hardware consumption tradeoffs,an optimal fixed-point word length of 5G mmWave waveform is given.The main work of this thesis is roughly divided into the following four parts:1.Mainly analysis the air interface waveforms discussed in the industry: Orthogonal Frequency Division Multiplexing(OFDM),Universal Filtered Multi-Carrier(UFMC),CP-OFDM with Weighted Overlap and Add(WOLA),Filtered Orthogonal Frequency Division Multiplexing(F-OFDM).The basic principles of these waveforms are described in details,and key properities,such as out-of-band Emission(OOBE),Peak-to-Average Power Ratio(PAPR)and BER performance in AWGN environment,are compared and analyzed.2.Three kinds of mmWave RF hardware impairments' models are studied: Power Amplifier Nonlinearity(PAN),Phase Noise(PN),and I/Q Imbalance(IQI).The effects of RF hardware impairments on waveforms are analyzed,and the performances of four waveforms under three mmWave RF hardware impairments are compared.3.For these three kinds of mmWave RF hardware impairments,the compensation methods are adopted separately: a nonlinear iterative elimination algorithm is used to eliminate the influence of the nonlinear distortion of the power amplifier on the waveforms.Based on the Phase Tracking Reference Signal(PT-RS)specified in the 3GPP TS 38.211 standard,a non-iterative phase noise compensation algorithm is proposed to compensate common phase error(CPE)and eliminate Inter-CarrierInterference(ICI),which are generated by phase noise.A blind estimation algorithm roughly compensates the I/Q imbalance,and then use the LMS algorithm to finely compensate the I/Q imbalance.Finally,the system BER performance of four waveforms after mmWave RF hardware impairments compensation is provided.4.These four waveforms are compared and analyzed from the aspects of resistance to mmWave RF hardware impairments,PAPR,overhead,multi-user frequency division multiplex capability,computational complexity and uplink-downlink symmetry.Based on tradeoffs in performance,complexity,etc.,OFDM is a more competitive 5G mmWave waveform.Through fixed-point simulation,considering the system performance and hardware resource consumption,the optimal fixed-point word length of IFFT implementation process of OFDM signal is obtained.