  This paper presents Bit-Interleaved Coded Modulation metrics for joint
estimation detection using training or reference signal transmission strategies
for short to long block length channels. We show that it is possible to enhance
the performance and sensitivity through joint detection-estimation compared to
standard receivers, especially when the channel state information is unknown
and the density of the training dimensions is low. The performance analysis
makes use of a full 5G transmitter and receiver chains for both Polar and LDPC
coded transmissions paired with BPSK/QPSK modulation schemes. We consider
transmissions where reference signals are interleaved with data and both are
transmitted over a small number of OFDM symbols so that near-perfect channel
estimation cannot be achieved. This is particularly adapted to mini-slot
transmissions for ultra-reliable, low-latency communications (URLLC) or for
short packet random access use cases. We characterize the performance for up to
eight receiving antennas in order to determine the performance gain offered by
the proposed BICM detection in realistic base station receiver scenarios. Our
findings demonstrate that when the detection windows used in the metric units
is on the order of four modulated symbols the proposed BICM metrics can be used
to achieve detection performance that is close to that of a coherent receiver
with perfect channel state information for both polar and LDPC coded
configurations. Furthermore, we show that for transmissions with low DMRS
density, a good trade-off can be achieved in terms of additional coding gain
and improved channel estimation quality by adaptive DMRS power adjustment.
