Receiver Metric Design for Short-Block Channels : A Perspective for Reliable 6G Signaling Scenarios

This paper introduces receiver metrics for joint estimation and detection in short block length channels, emphasizing enhanced performance for advanced receivers, especially in scenarios with unknown channel state information and low training dimension density. Utilizing a complete 5G transceiver chain for Polar and LDPC coded transmissions paired with QPSK modulation, we analyze interleaved reference signals and data over a small number of OFDM symbols, preventing near-perfect channel estimation. Suited for mini-slot transmissions in ultra-reliable, low-latency communications, our evaluation covers up to SIMO and SU-MIMO transmission configurations over Rayleigh block fading and Line-Of-Sight channels. Results show that, with detection windows of about four modulated symbols, the proposed BICM metrics achieve detection performance that is close to that of a coherent receiver with perfect channel state information for both polar and LDPC coded configurations.