CBTC Security and Reliability Enhancements by a Key-Based Direct Sequence Spread Spectrum Technique

A novel key-based Direct Sequence Spread Spectrum (DSSS) technique is proposed as a safety function for Communications-Based Train Control (CBTC) systems. According to well-known railway standards, namely IEEE 1474, IEC 61508, and EN 50128, CBTC systems should satisfy acceptable safety, security, and reliability levels. However, due to their inherent low-power features, prevalent CBTC systems cannot meet those levels perfectly in front of co-band interferences or attackers. Thus, a safety function is required which can be implemented without consuming much energy and restricted resources of CBTC systems. In this paper, the DSSS technique is based on a Cryptographically Secure Pseudo-Random Number Generator (CSPRNG). Comprehensive time-domain analysis shows how this safety function enhances the safety, security, and reliability of CBTC systems concerning the standards mentioned above. It is proved that any inauthentic signal turns into a Gaussian term with significantly mitigated power at the output of the CBTC receiver. It is also established how to determine appropriate communications parameters based on railway properties. The proposed scheme’s failure rate performance is compared with that of similar works. Additionally, computer simulations and experiments verify the efficiency of the proposed safety function.