In this letter, we investigate the downlink performance of massive multiple-input multiple-output (MIMO) systems where the base station is equipped with one-bit analog-todigital/digital-to-analog converters (ADC/DACs). We assume that the base station employs the linear minimum mean-squared-error channel estimator and treats the channel estimate as the true channel to precode the data symbols. We derive an expression for the downlink achievable rate for matched-filter precoding. A detailed analysis of the resulting power efficiency is pursued using our expression of the achievable rate. Numerical results are presented to verify our analysis. In particular, it is shown that, compared with conventional massive MIMO systems, the performance loss in one-bit massive MIMO systems can be compensated for by deploying approximately 2.5 times more antennas at the BS. Index Terms-Massive MIMO, one-bit quantization, downlink rate, MF precoding. M ASSIVE MIMO is an emerging technology capable of scaling up the performance of conventional MIMO by orders of magnitude. It has been shown that, with a base station (BS) equipped with a very large number of antennas, not only can the spectral efficiency and energy efficiency be significantly improved by employing simple linear signal processing techniques, but also the impact of imperfections in the hardware implementation can be mitigated [1], [2] . Most prior work has assumed that each antenna element in the massive MIMO system is equipped with a costly highresolution DAC, and hence has neglected the nonlinear effect of the quantization. The cost of using high-resolution DACs is manageable in conventional MIMO systems since the number Manuscript
For the simplest case that the massive MU-MIMO are deployed with 1-bit ADCs or DACs, it has been shown in a recent study REF that, compared with massive MIMO systems with ideal DACs, the sum rate loss in 1-bit massive MU-MIMO systems can be compensated by disposing approximately 2.5 times more antennas at the BS.
Downlink Achievable Rate Analysis in Massive MIMO Systems With One-Bit DACs
IEEE Communications Letters
IEEE Communications Letters
Mathematics Computer Science