Phase Noise Effect on Millimeter-Wave Pre-5G Systems

The introduction of millimeter waves for 5G wireless communication systems enables the use of more bandwidth and higher carrier frequency, surpassing the capacity of current systems by more than one order of magnitude. The leap of millimeter band results from the development of analog frontends that unfortunately induce relatively large phase noise in phase-locked loop synthesizers. Large phase noise may generate considerable random phase error and residual frequency offset, which in turn produces additional phase error. We evaluate phase error from phase noise on an implemented pre-5G system operating in the millimeter band and through a simulation by modeling the characteristics of a radio frequency integrated circuit. We measure and then compare the residual frequency offset, phase error, and error vector magnitude between the experimental and simulation results. We verify that the phase noise model suitably approximates to the real conditions. Moreover, we show that phase error remains at approximately 4° in the implemented system. By exploiting the implemented phase error compensation, our pre-5G system can overcome a degradation of 1.5 dB in error vector magnitude and achieve an approximate transmission rate of 4 Gbps at gain of 1.49.