1,496 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
Performance of Integrated IoT Network with Hybrid mmWave/FSO/THz Backhaul Link
Establishing end-to-end connectivity of Internet of Things (IoT) network with
the core for collecting sensing data from remote and hard-to-reach terrains is
a challenging task. In this article, we analyze the performance of an IoT
network integrated with wireless backhaul link for data collection. We propose
a solution that involves a self-configuring protocol for aggregate node (AN)
selection in an IoT network, which sends the data packet to an unmanned aerial
vehicle (UAV) over radio frequency (RF) channels. We adopt a novel hybrid
transmission technique for wireless backhaul employing opportunistic selections
combining (OSC) and maximal ratio combining (MRC) that simultaneously transmits
the data packet on mmWave (mW), free space optical (FSO), and terahertz (THz)
technologies to take advantage of their complementary characteristics. We
employ the decode-and-forward (DF) protocol to integrate the IoT and backhaul
links and provide physical layer performance assessment using outage
probability and average bit-error-rate (BER) under diverse channel conditions.
We also develop simplified expressions to gain a better understanding of the
system's performance at high signal-to-noise ratio (SNR). We provide computer
simulations to compare different wireless backhaul technologies under various
channel and SNR scenarios and demonstrate the performance of the data
collection using the integrated link.Comment: This work has been submitted to IEEE for possible publicatio
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