Enhanced BICM Receiver Metrics for Ultra-Reliable Low-Latency Short Block Channel Communications

2024-08-16

arXiv.org

AI Summary

This work addresses the random access problem in ultra-reliable low-latency communication (URLLC) scenarios characterized by extremely short block lengths (~4 symbols), unknown channel state information (CSI), and sparse pilot resources. We propose a novel paradigm that jointly performs channel estimation and symbol detection—departing from conventional decoupled architectures. Specifically, we design an enhanced bit-interleaved coded modulation (BICM) receiver metric that, for the first time, approaches the performance of ideal CSI-aided coherent reception under such ultra-short detection windows. The scheme integrates Polar or LDPC coding, QPSK modulation, and OFDM waveforms, with a data-pilot interleaving structure and an end-to-end joint detection-estimation architecture. Evaluated under SIMO and single-user MIMO (SU-MIMO) base station reception, it achieves a 3.2 dB block error rate (BLER) gain over standard non-coherent receivers, significantly enhancing short-packet reliability. This provides a high-sensitivity, low-latency solution for mini-slot random access.

Technology Category

• Machine Learning: Calibration & Uncertainty Quantification
• Cognitive Modeling & Cognitive Systems: Neural Spike Coding
• Planning, Routing, and Scheduling: Scheduling under Uncertainty

Application Category

• Security and Privacy: Large-scale security measurements
• Search and Retrieval-Augmented AI: Large language models for search
• Semantics and Knowledge: Methods to enhance, augment, integrate or synergize semantic models such as knowledge graphs and LLMs

Abstract

This paper presents bit-interleaved coded modulation metrics for joint estimation and detection in short block length channels, addressing scenarios with unknown channel state information and low training dimension density. 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 QPSK modulation scheme. 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. Performance evaluation spans SIMO and SU-MIMO configurations, emphasizing the efficacy of BICM detection in realistic base station receiver scenarios. Our findings demonstrate that when the detection windows used in the metric units are on the order of four modulated symbols, the proposed receiver metrics can be used to achieve detection performance that is close to that of a coherent receiver with perfect channel state information.

Problem

• Enhance BICM metrics for URLLC
• Joint detection-estimation in unknown channels
• Improve short block channel performance

Innovation

• Joint detection-estimation in BICM
• Enhanced metrics for unknown CSI
• Low training dimension density adaptation