Secure & efficient intra-MME handovers via mobile relays within the LTE-A and future 5G high-speed train networks

Nowadays, train networks are the most salient transportation mediums which demand higher data rates and reliable communication services for the onboard user equipments (UEs) over their long travels. The major issue associated with the high-speed train networks is that the frequent Long Term Evolution Advanced (LTE-A) Intra-MME handovers between the base stations generate high signaling overheads within the core network. Moreover, these LTE-A Intra-MME handovers are vulnerable to the desynchronization attack and cannot achieve forward key separation over the handovers. Therefore, the Intra-MME handovers cannot ensure access stratum (AS) secrecy. To improve the quality of services within the high-speed networks, recently, mobile relay nodes (MRNs) are incorporated into the LTE-A enabled high-speed vehicular networks. While the practice of these third-party MRNs may pose new security challenges. This research enlightens the loopholes which exist within the LTE-A Intra-MME handover protocol and proposes a more secure and efficient hierarchical grouping based Intra-MME handover protocol which is more suitable for the high-speed train networks. The proposed protocol promises to measure the minimum number of objects (base stations) over the measurement execution phase, optimizes the signaling overheads and reduces the handover processing time (handover interrupt time). Furthermore, to maintain the access stratum (AS) secrecy, the proposed protocol ensures secure handover session key establishment between the onboard UEs and the TDeNB. To demonstrate the effectiveness and efficiency of the proposed protocol, its performance is evaluated mathematically and security validations are carried out by various extensive simulations on Automated Validation of Internet Security Protocols and Applications (AVISPA) tool and BAN logic.