An Architecture for High Data Rate Very Low Frequency Communication

  • Arun Kumar Indian Institute of Technology Delhi, New Delhi
  • Rajendar Bahl Indian Institute of Technology Delhi, New Delhi
Keywords: Communication systems, VLF Communication, GMSK modulation, LDPC codes, atmospheric radio noise


Very low frequency (VLF) communication is used for long range shore-to-ship broadcasting applications. This paper proposes an architecture for high data rate VLF communication using Gaussian minimum shift keying (GMSK) modulation and low delay parity check (LDPC) channel coding. Non-data aided techniques are designed and used for carrier phase synchronization, symbol timing recovery, and LDPC code frame synchronization. These require the estimation of the operative Eb/N0 for which a kurtosis based algorithm is used. Also, a method for modeling the probability density function of the received signal under the bit condition is presented in this regard. The modeling of atmospheric radio noise (ARN) that corrupts VLF signals is described and an algorithm for signal enhancement in the presence of ARN in given. The BER performance of the communication system is evaluated for bit rates of 400 bps, 600 bps, and 800 bps for communication bandwidth of ~200 Hz.

Defence Science Journal, 2013, 63(1), pp.25-33DOI:

Author Biographies

Arun Kumar, Indian Institute of Technology Delhi, New Delhi
Dr Arun Kumar received the BTech, MTech, and PhD in Electrical Engineering from the Indian Institute of Technology, Kanpur in 1988, 1990, and 1995 respectively. He is currently Professor and Head, Centre for Applied Research in Electronics, IIT Delhi. He has published 75 research papers and has supervised 40 funded R&D projects from Indian and foreign industries, as well as various government organizations. He is a recipient of the Young Scientist award of the International Union of Radio Science. His current R&D work encompasses the topics of acoustics based target localization, voice personality transformation, text-to-speech synthes is in Indian languages, localization of acoustic transient signals, underwater acoustic communications, VLF communications, underwater acoustic signal processing, and design and realization of low power DSP hardware systems for remote unmanned operations.
Rajendar Bahl, Indian Institute of Technology Delhi, New Delhi
Professor R. Bahl is a member of the faculty of CARE, IIT Delhi, where he heads the Signal Processing Group. He obtained his BTech (Electronics and Electrical Comm. Engg.) in 1974 from IIT Kharagpur, and his PhD (Electrical Engineering) IIT Delhi in 1982. His main area of work is in Underwater Electronics. He has delivered a number of projects, such as: a state-of-the-art 3D imaging sonar SOBID, Programmable test signal generator for sonars, object visualisation using imaging sonars, CAD software package for high-resolution imaging sonars that simulates acoustic images of 3-D scenarios, MSK and GMSK modem design for VLF communication, Compact multiplexed multichannel SONAR system with proven superior performance in actual sea-trials: know how transferred to industry.
How to Cite
Kumar, A., & Bahl, R. (2013). An Architecture for High Data Rate Very Low Frequency Communication. Defence Science Journal, 63(1), 25-33.