150 research outputs found
On Low-Resolution ADCs in Practical 5G Millimeter-Wave Massive MIMO Systems
Nowadays, millimeter-wave (mmWave) massive multiple-input multiple-output
(MIMO) systems is a favorable candidate for the fifth generation (5G) cellular
systems. However, a key challenge is the high power consumption imposed by its
numerous radio frequency (RF) chains, which may be mitigated by opting for
low-resolution analog-to-digital converters (ADCs), whilst tolerating a
moderate performance loss. In this article, we discuss several important issues
based on the most recent research on mmWave massive MIMO systems relying on
low-resolution ADCs. We discuss the key transceiver design challenges including
channel estimation, signal detector, channel information feedback and transmit
precoding. Furthermore, we introduce a mixed-ADC architecture as an alternative
technique of improving the overall system performance. Finally, the associated
challenges and potential implementations of the practical 5G mmWave massive
MIMO system {with ADC quantizers} are discussed.Comment: to appear in IEEE Communications Magazin
Channel Estimation and Uplink Achievable Rates in One-Bit Massive MIMO Systems
This paper considers channel estimation and achievable rates for the uplink
of a massive multiple-input multiple-output (MIMO) system where the base
station is equipped with one-bit analog-to-digital converters (ADCs). By
rewriting the nonlinear one-bit quantization using a linear expression, we
first derive a simple and insightful expression for the linear minimum
mean-square-error (LMMSE) channel estimator. Then employing this channel
estimator, we derive a closed-form expression for the lower bound of the
achievable rate for the maximum ratio combiner (MRC) receiver. Numerical
results are presented to verify our analysis and show that our proposed LMMSE
channel estimator outperforms the near maximum likelihood (nML) estimator
proposed previously.Comment: 5 pages, 2 figures, the Ninth IEEE Sensor Array and Multichannel
Signal Processing Worksho
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