  This paper considers a low-resolution wireless communication system in which
transmitted signals are corrupted by fading and additive noise. First, a
universal lower bound on the average symbol error probability (SEP), correct
for all M-ary modulation schemes, is obtained when the number of quantization
bits is not enough to resolve M signal points. Second, in the special case of
M-ary phase shift keying (M-PSK), the optimum maximum likelihood detector for
equiprobable signal points is derived. Third, utilizing the structure of the
derived optimum receiver, a general average SEP expression for the M-PSK
modulation with n-bit quantization is obtained when the wireless channel is
subject to fading with a circularly-symmetric distribution. Finally, an
extensive simulation study of the derived analytical results is presented for
general Nakagami-m fading channels. It is observed that a transceiver
architecture with n-bit quantization is asymptotically optimum in terms of
communication reliability if n is greater than or equal to log_2(M +1). That
is, the decay exponent for the average SEP is the same and equal to m with
infinite-bit and n-bit quantizers for n greater than or equal to log_2(M+1). On
the other hand, it is only equal to half and 0 for n = log_2(M) and n <
log_2(M), respectively. Hence, for fading environments with a large value of m,
using an extra quantization bit improves communication reliability
significantly.
