On the Performance of Cell Free Massive MIMO With Mixed ADC Under Rician Fading Channels
In this letter, we introduce a mixed analog to digital converter (ADC) receiver architecture to cell free massive multi input multi output (mMIMO) system under Rician fading channels. In particular, the mixed ADC architecture permits some of receiver's antennas to be implemented with economical low resolution ADCs, while the rests are equipped with high priced perfect ADCs. Leveraging on the additive quantization noise model (AQNM) a tight approximate uplink spectral efficiency (SE) expression with matched filtering receiver is derived, which provides us with a tool for easily quantifying the impacts of the Rician {K} factor, the quantization bit of low resolution ADCs, and the proportion of the perfect ADCs in the mixed ADC architecture. Numerical observations demonstrate that the mixed ADC architecture with a small fraction of perfect ADCs has a great potential to boost the SE compared to the case with pure low resolution ADCs. Moreover, the mixed ADC architecture is superior to the full perfect ADCs counterpart in terms of energy efficiency (EE)
IEEE Communications Letters