Stochastic game-based cross-layer defense scheme for jamming-resistant virtual coupled train sets

The railway operation concept of Virtually Coupled Train Sets (VCTS) allows for shorter headways between units in a train convoy, enhancing the current capacity limit imposed by existing Communication-Based Train Control (CBTC) systems by enabling units to operate safely at shorter distances. However, due to the use of open Train-to-Train (T2T) wireless communication through Long-Terms Evolution for Metro (LTE-M), VCTS is vulnerable to various cyber-attacks, including jamming attacks, which have largely been overlooked. To address this issue, this paper proposes a Stochastic Game-Based Cross-Layer Defense (SGCD) scheme. This scheme aims to enhance the safety and stability of VCTS in both the physical and cyber layers, in the presence of uncertain communication failures caused by jamming attacks. This proposed scheme formulates the defense approach and the particularly jamming actions as a stochastic game. A cross-layer control approach is employed to mitigate the impact of jamming attacks on the train convoy. The performance of this cross-layer control is mapped to the frequency domain and quantified using the $H^{\infty }$ norm to ensure the stability and safety of the VCTS system. Extensive simulation results demonstrate that the SGCD scheme can effectively ensure the running stability and safety of a train convoy under random jamming attacks in the VCTS. The proposed defense mechanism can enhance the security and reliability of the VCTS system, thereby enabling safer and more efficient train operations with shorter headways.