Massive MIMO Uplink Systems With Low-Resolution ADC: Equal Gain Combining Approach

Since massive multiple-input multiple-output (MIMO) systems for fifth generation (5G) wireless communications require a large number of antennas, resulting in a substantial increase in hardware cost and power consumption, the use of low-resolution analog-to-digital converter (ADC) can be considered to reduce this impact. In this paper, we investigate the uplink spectral efficiency (SE) performance of massive MIMO systems with low-resolution ADC in Rician fading channels, where perfect and imperfect channel state information (CSI) are taken into account, and derive approximate expressions of uplink spectral efficiency for equal gain combining (EGC) approach. In addition, the effects of ADC resolution, Rician factor and the number of base station (BS) antennas on the spectral efficiency are analyzed. The results show that under perfect and imperfect CSI, the transmitting power can be reduced to the reciprocal of the antenna at the lowest, that is, $1 / M$, and the spectral efficiency will eventually approach a fixed value with the increase of Rician factor. In massive MIMO systems, good spectral efficiency performance can still be obtained by using low-resolution ADC.