Bounds for Joint Detection and Decoding on the Binary-Input AWGN Channel
Simon Obermüller, Jannis Clausius, Marvin Geiselhart, Stephan ten Brink
TL;DR
This work establishes finite-blocklength bounds for joint detection and decoding (JDD) on the binary-input AWGN channel, analyzing two schemes: decoder-aided detection (DAD) and hybrid preamble and energy detection (HyPED). It derives both achievability and converse bounds for the information rate and a general blocklength bound for JDD, showing that DAD can rapidly approach the rate of synchronous transmission, outperforming preamble-based detection and distribution-based bounds. The results are supported by numerical bounds and simulations of practical codes, demonstrating substantial gains in inclusive error rate and suggesting practical design trade-offs between detection and decoding performance. The findings contribute to a deeper theoretical understanding of asynchronous JDD limits and guide the design of low-overhead receivers for IoT, mMTC, and URLLC.
Abstract
For asynchronous transmission of short blocks, preambles for packet detection contribute a non-negligible overhead. To reduce the required preamble length, joint detection and decoding (JDD) techniques have been proposed that additionally utilize the payload part of the packet for detection. In this paper, we analyze two instances of JDD, namely hybrid preamble and energy detection (HyPED) and decoder-aided detection (DAD). While HyPED combines the preamble with energy detection for the payload, DAD also uses the output of a channel decoder. For these systems, we propose novel achievability and converse bounds for the rates over the binary-input additive white Gaussian noise (BI-AWGN) channel. Moreover, we derive a general bound on the required blocklength for JDD. Both the theoretical bound and the simulation of practical codebooks show that the rate of DAD quickly approaches that of synchronous transmission.
