TY - GEN

T1 - Coherent MU-MIMO in Block Fading Channels: A Finite Blocklength Analysis

AU - Feng, Junjuan

AU - Ngo, Hien-Quoc

AU - Matthaiou, Michalis

PY - 2020/7/21

Y1 - 2020/7/21

N2 - This paper investigates the maximum coding
rate of the multiple-user multiple-input-multiple-output (MUMIMO) uplink in coherent block-fading channels and with finite
blocklength. The backoff of the maximum coding rate from the
capacity caused by finite blocklength is precisely characterized
by a parameter, called the channel dispersion. In particular, we
derive exact analytical and approximation results for a large
number of the base station (BS) antennas. By analyzing these
results, we observe that even when considering the channel
dispersion, the maximum coding rate still increases with respect
to the number of BS antennas, whilst the SNR for each user can
also improve the performance to a ceiling limited by the interuser interference. Fast channel dynamics (shorter coherence
time) and high diversity gain (large number of blocks) are
beneficial for the maximum coding rate under finite blocklength
and coherent setting. Moreover, to obtain a certain fraction of
the capacity with fixed error probability, the minimum required
blocklength (delay) can be reduced by increasing the number
of BS antennas. We also show that the channel dispersion will
converge to a constant while the minimum required blocklength
can approach to zero with massive number of the BS antennas.
Hence, from a theoretical viewpoint, deploying a large number
of the BS antennas is beneficial for low latency communications.

AB - This paper investigates the maximum coding
rate of the multiple-user multiple-input-multiple-output (MUMIMO) uplink in coherent block-fading channels and with finite
blocklength. The backoff of the maximum coding rate from the
capacity caused by finite blocklength is precisely characterized
by a parameter, called the channel dispersion. In particular, we
derive exact analytical and approximation results for a large
number of the base station (BS) antennas. By analyzing these
results, we observe that even when considering the channel
dispersion, the maximum coding rate still increases with respect
to the number of BS antennas, whilst the SNR for each user can
also improve the performance to a ceiling limited by the interuser interference. Fast channel dynamics (shorter coherence
time) and high diversity gain (large number of blocks) are
beneficial for the maximum coding rate under finite blocklength
and coherent setting. Moreover, to obtain a certain fraction of
the capacity with fixed error probability, the minimum required
blocklength (delay) can be reduced by increasing the number
of BS antennas. We also show that the channel dispersion will
converge to a constant while the minimum required blocklength
can approach to zero with massive number of the BS antennas.
Hence, from a theoretical viewpoint, deploying a large number
of the BS antennas is beneficial for low latency communications.

U2 - 10.1109/ICCWorkshops49005.2020.9145415

DO - 10.1109/ICCWorkshops49005.2020.9145415

M3 - Conference contribution

SN - 978-1-7281-7441-9

T3 - IEEE International Conference on Communications Workshops (ICC Workshops): Proceedings

BT - 2020 IEEE International Conference on Communications Workshops (ICC Workshops): Proceedings

PB - IEEE

ER -