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When Are Low Resolution ADCs Energy Efficient in Massive MIMO?

Sarajlic, Muris LU ; Liu, Liang LU and Edfors, Ove LU (2017) In IEEE Access 5.
Abstract
Massive MIMO (MaMI) is often promoted as a technology that will enable the use of low-quality, cheap hardware. One particular component that has been in the focus of MaMI-related research is the analog-to-digital converter (ADC), and use of very low-resolution ADCs has been proposed. However, studies about whether this strategy is justified from an energy-efficiency point of view have largely been inconclusive. In this paper, we choose system setup and models that reflect the hardware implementation reality as close as possible and perform a parametric analysis of uplink energy efficiency as a function of ADC resolution. If antenna scaling and decrease of ADC resolution are considered independently, the energy efficiency is shown to be... (More)
Massive MIMO (MaMI) is often promoted as a technology that will enable the use of low-quality, cheap hardware. One particular component that has been in the focus of MaMI-related research is the analog-to-digital converter (ADC), and use of very low-resolution ADCs has been proposed. However, studies about whether this strategy is justified from an energy-efficiency point of view have largely been inconclusive. In this paper, we choose system setup and models that reflect the hardware implementation reality as close as possible and perform a parametric analysis of uplink energy efficiency as a function of ADC resolution. If antenna scaling and decrease of ADC resolution are considered independently, the energy efficiency is shown to be maximized at intermediate ADC resolutions, typically in the range of 4–8 bits. Moreover, optimal ADC resolution does not decrease when more antennas are used except in some specific cases, and when it does, the decrease is approximately logarithmic in the number of antennas. In the case when antenna scaling and ADC degradation are coupled through a constant-performance constraint, it is shown that energy efficiency cannot improve with reduced bit resolution unless the power consumption of blocks other than ADCs scales down with the upscaling of antennas at a fast enough rate. Altogether it is concluded that in MaMI, intermediate ADC resolutions are optimal in energy efficiency sense, and, except in some special cases, scaling up the antennas to very large numbers does not change this conclusion. (Less)
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published
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in
IEEE Access
volume
5
publisher
IEEE--Institute of Electrical and Electronics Engineers Inc.
ISSN
2169-3536
language
English
LU publication?
yes
id
febdbeb3-c3f1-4fd6-8db4-8f032f110ea8
alternative location
http://ieeexplore.ieee.org/document/7990217/
date added to LUP
2017-09-12 10:35:51
date last changed
2017-09-12 11:06:49
@article{febdbeb3-c3f1-4fd6-8db4-8f032f110ea8,
  abstract     = {Massive MIMO (MaMI) is often promoted as a technology that will enable the use of low-quality, cheap hardware. One particular component that has been in the focus of MaMI-related research is the analog-to-digital converter (ADC), and use of very low-resolution ADCs has been proposed. However, studies about whether this strategy is justified from an energy-efficiency point of view have largely been inconclusive. In this paper, we choose system setup and models that reflect the hardware implementation reality as close as possible and perform a parametric analysis of uplink energy efficiency as a function of ADC resolution. If antenna scaling and decrease of ADC resolution are considered independently, the energy efficiency is shown to be maximized at intermediate ADC resolutions, typically in the range of 4–8 bits. Moreover, optimal ADC resolution does not decrease when more antennas are used except in some specific cases, and when it does, the decrease is approximately logarithmic in the number of antennas. In the case when antenna scaling and ADC degradation are coupled through a constant-performance constraint, it is shown that energy efficiency cannot improve with reduced bit resolution unless the power consumption of blocks other than ADCs scales down with the upscaling of antennas at a fast enough rate. Altogether it is concluded that in MaMI, intermediate ADC resolutions are optimal in energy efficiency sense, and, except in some special cases, scaling up the antennas to very large numbers does not change this conclusion.},
  author       = {Sarajlic, Muris and Liu, Liang and Edfors, Ove},
  issn         = {2169-3536},
  language     = {eng},
  month        = {07},
  publisher    = {IEEE--Institute of Electrical and Electronics Engineers Inc.},
  series       = {IEEE Access},
  title        = {When Are Low Resolution ADCs Energy Efficient in Massive MIMO?},
  volume       = {5},
  year         = {2017},
}