A Deep Learning-based Receiver for Asynchronous Grant-Free Random Access in Control-to-Control Networks

TL;DR

This paper introduces a deep learning-based receiver architecture for asynchronous grant-free C2C communication, enabling reliable detection and decoding of command units in shared wireless channels.

Contribution

It proposes a CNN-based receiver that detects command boundaries and decodes signals, improving performance in asynchronous, high-traffic C2C networks.

Findings

Achieves reliable packet boundary detection in asynchronous scenarios.

Demonstrates low packet loss rate under high traffic conditions.

Utilizes soft information and SIC for enhanced decoding.

Abstract

In this paper, we study grant-free, asynchronous control-to-control (C2C) communications in an indoor scenario with a shared wireless channel. Each communication node transmits command units, each consisting of a variable-length low-density parity-check (LDPC)--coded payload preceded by a start sequence and followed by a tail sequence. Due to the asynchronous nature of the access, transmissions from different nodes are not aligned over time. As a result, each receiving controller observes the superposition of multiple command units transmitted by different nodes over a receiver-defined superframe interval. Each node transmits one or more replicas of the same command unit. We propose a receiver architecture in which the detection of command unit boundaries (start/tail sequences) is carried out by a single convolutional neural network (CNN) operating directly on the received signal. We show that, while start-sequence detection must rely only on the received waveform, tail-sequence detection can additionally exploit the soft information produced by the LDPC decoder, together with channel estimates. Finally, once commands units are successfully decoded, successive interference cancellation (SIC) can be applied. Simulation results demonstrate that the receiver we propose achieves reliable packet-boundary identification and a low end-to-end packet loss rate, even under uncoordinated and high-traffic operating conditions.