  This paper studies the spectral/energy efficiency (SE/EE) of a heterogeneous
network with the backhaul enabled by low-resolution analog-to-digital
converters (ADCs) quantized full-duplex massive multiple-input multiple-output
(MIMO) over Rician channels. Backhaul communication is completed over two
phases. During the first phase, the macro-cell (MC) base station (BS) deploys
massive receive antennas and a few transmit antennas; the small-cell (SC) BSs
employ large-scale receive antennas and a single transmit antenna. For the
second phase, the roles of the transmit and receive antennas are switched. Due
to the low-resolution ADCs, we account for quantization noise (QN). We
characterize the joint impact of the number of antennas, self-interference,
SC-to-SC interference, QN, and Rician K-factor. For the first phase, the SE is
enhanced with the massive receive antennas and the loss due to QN is limited.
For the second phase, the desired signal and QN have the same order. Therefore,
the SE saturates with the massive transmit antennas. As the Rician K-factor
increases, the SE converges. Power scaling laws are derived to demonstrate that
the transmit power can be scaled down proportionally to the massive antennas.
We investigate the EE/SE trade-offs. The envelope of the EE/SE region grows
with increase in the Rician K-factor.
