  We use stochastic network calculus to investigate the delay performance of a
multiuser MISO system with zero-forcing beamforming. First, we consider ideal
assumptions with long codewords and perfect CSI at the transmitter, where we
observe a strong channel hardening effect that results in very high reliability
with respect to the maximum delay of the application. We then study the system
under more realistic assumptions with imperfect CSI and finite blocklength
channel coding. These effects lead to interference and to transmission errors,
and we derive closed-form lower and upper bounds on the resulting error
probability. Compared to the ideal case, imperfect CSI and finite length coding
cause massive degradations in the average transmission rate. Surprisingly, the
system nevertheless maintains the same qualitative behavior as in the ideal
case: as long as the average transmission rate is higher than the arrival rate,
the system can still achieve very high reliability with respect to the maximum
delay.
