On Efficient and Low-Complexity Decoding of Binary LDPC-Coded CSK Signals for GNSS Links with Increased Data Rates

• Published in: 2020 IEEE/ION Position, Location and Navigation Symposium (PLANS) pp. 1202 - 1213
• Main Authors: Chauvat, Remi, Garcia-Pena, Axel, Paonni, Matteo
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.04.2020
• ISSN: 2153-3598
• DOI: 10.1109/PLANS46316.2020.9110196

GNSS with high data rate links are of interest to accommodate new needs and applications (e.g. precise positioning, authentication, reduction of TTFFD). In this context, a binary LDPC-coded CSK signal is an attractive candidate to increase data rates with a high data recovery robustness. However, such a proposal requires an increase of receiver's computational complexity with respect to receivers for current coded DSSS/BPSK GNSS links. The computational complexity required for data recovery is analysed in this article and insights on crucial technical choices are given for the reception of binary LDPC-coded CSK signals. CSK demodulation is shown to dominate the overall computational cost and the use of digital chip-matched filtering prior to demodulation is proposed to reduce this cost. In addition, iterative demapping, which is crucial to optimize the power efficiency of binary LDPC-coded CSK links is also shown to have high computational complexity. Therefore, low-complexity iterative demapping strategies are studied and simple yet efficient solutions are proposed.