Novel Joint Estimation and Decoding Metrics for Short-Blocklength Transmission Systems

2023-11-06

IEEE Conference on Standards for Communications and Networking

AI Summary

This paper addresses performance degradation in short-block-length transmission systems caused by unknown channel state information (CSI) and low-density pilot signals. We propose a joint detection and channel estimation framework for bit-interleaved coded modulation (BICM). Our key contributions are: (1) a novel joint BICM metric enabling end-to-end joint decoding and estimation assisted by training signals; (2) the first demonstration in OFDM systems of near-ideal coherent reception performance with only a 4-symbol detection window; and (3) an adaptive Demodulation Reference Signal (DMRS) power allocation scheme that jointly optimizes channel estimation accuracy and coding gain under low-overhead constraints. Evaluated on a full 5G link—featuring Polar/LDPC coding, BPSK/QPSK modulation, and OFDM—the scheme achieves significantly lower bit error rates (BER) than conventional separate-receiver architectures for ultra-short blocks (<64 bits), delivering up to 1.8 dB coding gain and approaching the perfect-CSI performance bound even with sparse DMRS placement.

Technology Category

Cognitive Modeling & Cognitive Systems: Neural Spike CodingIntelligent Robots: State EstimationSearch and Optimization: Learning to Search

Application Category

User Modeling, Personalization and Recommendation: On-Device user modeling, personalization, and recommendationSecurity and Privacy: Large-scale security measurementsSearch and Retrieval-Augmented AI: Web evaluation methodologies and metrics

Abstract

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. 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.

Problem

• Enhance performance in short-block length transmissions
• Improve channel estimation with low training signal density
• Adapt DMRS power for better coding gain

Innovation

• Joint estimation-detection enhances performance
• Adaptive DMRS power adjustment improves quality
• BICM metrics near coherent receiver performance