Performance Analysis of Mixed-ADC Massive MIMO Systems over Rician Fading Channels

摘要

The practical deployment of massive multiple-input multiple-output (MIMO) infuture fifth generation (5G) wireless communication systems is challenging dueto its high hardware cost and power consumption. One promising solution toaddress this challenge is to adopt the low-resolution analog-to-digitalconverter (ADC) architecture. However, the practical implementation of sucharchitecture is challenging due to the required complex signal processing tocompensate the coarse quantization caused by low-resolution ADCs. Therefore,few high-resolution ADCs are reserved in the recently proposed mixed-ADCarchitecture to enable low-complexity transceiver algorithms. In contrast toprevious works over Rayleigh fading channels, we investigate the performance ofmixed-ADC massive MIMO systems over the Rician fading channel, which is moregeneral for the 5G scenarios like Internet of Things (IoT). Specially, novelclosed-form approximate expressions for the uplink achievable rate are derivedfor both cases of perfect and imperfect channel state information (CSI). Withthe increasing Rician $K$-factor, the derived results show that the achievablerate will converge to a fixed value. We also obtain the power-scaling law thatthe transmit power of each user can be scaled down proportionally to theinverse of the number of base station (BS) antennas for both perfect andimperfect CSI. Moreover, we reveal the trade-off between the achievable rateand energy efficiency with respect to key system parameters including thequantization bits, number of BS antennas, Rician $K$-factor, user transmitpower, and CSI quality. Finally, numerical results are provided to show thatthe mixed-ADC architecture can achieve a better energy-rate trade-off comparedwith the ideal infinite-resolution and low-resolution ADC architectures.