An improved link-16/JTIDS receiver in pulsed-noise interference

Abstract

Link-16 provides presumably secure and jam-resistant tactical information for land, sea, and air platforms. Its communication terminal, Joint Tactical Information Distribution System (JTIDS), is a hybrid direct-sequence/frequency-hopping spread spectrum system and features Reed-Solomon (RS) codes for channel coding, cyclic code-shift keying (CCSK) for 32-ary baseband symbol modulation, and minimum-shift keying (MSK) for waveform modulation. In this paper, a noise-normalization combining MSK chip demodulator and an errors-and-erasures RS decoder (EED) are proposed in the JTIDS receiver to replace the original MSK chip demodulator and errors-only RS decoder in order to enhance the anti-jam capability of JTIDS. The symbol error rate (SER) performances of the proposed JTIDS receiver are investigated in pulsed-noise interference (PNI) by a combination of analysis and simulation assuming perfect frequency de-hopping, sequence and chip synchronization, and de-scrambling. Given various fraction of time the jammer is on, the SER performances obtained with the proposed JTIDS receiver are compared to those obtained with the original JTIDS receiver. The results show that the proposed JTIDS receiver not only significantly outperforms the original system as the fraction of time the jammer is on is large, but completely eliminates the effect caused by PNI as the fraction of time the jammer is on is small.