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Spectrally Efficient LDPC Codes For IRIG-106 Waveforms via Random Puncturing

Andrew D. Cummins, David G. M. Mitchell, Erik Perrins

TL;DR

The paper addresses spectral efficiency of IRIG-106 waveforms by applying random puncturing to LDPC codes designed for ARTM CPM, enabling rate-compatible operation without hardware changes. It shows that modest puncturing can raise the effective rate (Rp) while preserving decoding performance, especially when CPM is incorporated, which provides substantial coding gains (over 2 dB) compared to uncoupled coding. The study also discusses implementation considerations, showing that puncturing and depuncturing can be realized with minimal hardware impact and modest latency. The authors suggest future work on density evolution for puncturing patterns and nonrandom schemes to further close the gap to native higher-rate codes, enabling adaptive bandwidth management in CPM-based telemetry systems.

Abstract

Low-density parity-check (LDPC) codes form part of the IRIG-106 standard and have been successfully deployed for the Telemetry Group version of shaped-offset quadrature phase shift keying (SOQPSK-TG) modulation. Recently, LDPC code solutions have been proposed and optimized for continuous phase modulations (CPMs), including the pulse code modulation/frequency modulation (PCM/FM) and the multi-h CPM developed by the Advanced Range TeleMetry program (ARTM CPM). These codes were shown to perform around one dB from the respective channel capacities of these modulations. In this paper, we consider the effect of random puncturing of these LDPC codes to further improve spectrum efficiency. We present numerical simulation results that affirm the robust decoding performance promised by LDPC codes designed for ARTM CPM.

Spectrally Efficient LDPC Codes For IRIG-106 Waveforms via Random Puncturing

TL;DR

The paper addresses spectral efficiency of IRIG-106 waveforms by applying random puncturing to LDPC codes designed for ARTM CPM, enabling rate-compatible operation without hardware changes. It shows that modest puncturing can raise the effective rate (Rp) while preserving decoding performance, especially when CPM is incorporated, which provides substantial coding gains (over 2 dB) compared to uncoupled coding. The study also discusses implementation considerations, showing that puncturing and depuncturing can be realized with minimal hardware impact and modest latency. The authors suggest future work on density evolution for puncturing patterns and nonrandom schemes to further close the gap to native higher-rate codes, enabling adaptive bandwidth management in CPM-based telemetry systems.

Abstract

Low-density parity-check (LDPC) codes form part of the IRIG-106 standard and have been successfully deployed for the Telemetry Group version of shaped-offset quadrature phase shift keying (SOQPSK-TG) modulation. Recently, LDPC code solutions have been proposed and optimized for continuous phase modulations (CPMs), including the pulse code modulation/frequency modulation (PCM/FM) and the multi-h CPM developed by the Advanced Range TeleMetry program (ARTM CPM). These codes were shown to perform around one dB from the respective channel capacities of these modulations. In this paper, we consider the effect of random puncturing of these LDPC codes to further improve spectrum efficiency. We present numerical simulation results that affirm the robust decoding performance promised by LDPC codes designed for ARTM CPM.
Paper Structure (9 sections, 7 figures)

This paper contains 9 sections, 7 figures.

Table of Contents

  1. ABSTRACT
  2. INTRODUCTION
  3. BACKGROUND
  4. RANDOM PUNCTURING
  5. NUMERICAL RESULTS
  6. ISOLATED CODE
  7. CPM INCLUDED
  8. HARDWARE CONSIDERATIONS
  9. CONCLUDING REMARKS

Figures (7)

  • Figure 1: Model transmitter for punctured LDPC code with CPM modulation.
  • Figure 2: Model receiver for punctured LDPC code with CPM modulation and iterative decoding.
  • Figure 3: Puncturing by truncation and depuncturing by zero-padding within the global decoding loop of the receiver.
  • Figure 4: Simplified transceiver model without CPM.
  • Figure 5: BER performance for the $R=2/3$, $N=1024$ ARTM LDPC code with and without random puncturing.
  • ...and 2 more figures