A Secure and Low-Latency Design for Ldacs Ground Station Handover

L-band Digital Aeronautical Communications System (LDACS) has been developed to provide a secure and high-throughput aviation communication service. Unfortunately, the state-of-the-art of the LDACS handover mechanism fails to protect station identity information and incurs excessive handover latency. In order to tackle these issues, this paper proposes a secure and low-latency handover scheme, with the aid of anonymous identity and of aircrafts' trajectories. The handover scheme proposed is comprised of two stages, namely, pre-handover and handover. In contrast to the current handover scheme where the ground station is selected for the maximum received power, in our pre-handover stage, the ground station to be connected is predictively pre-selected following the aircraft's trajectory planned. As a benefit, the authentication between the aircraft and the ground station to be connected can be prepared before handover. To realize this, a periodic renewal of temporary identity code is introduced for each key establishment, to attain the anonymity both of aircraft and ground station. Following this, the token including the aforementioned encryption authentication result is sent to the aircraft. In this case, the complicated mutual authentication and key establishment between the aircraft and the ground station to be connected can be avoided, which may accelerate the handover process. As for the handover stage, the aircraft's anonymous identity information along with the token acquired are sent to the next ground station. Then, the aircraft's authenticated result in the token is verified using the private key of LDACS access network. As such, the aircraft can be quickly handed over to the ground station to be connected. To validate the scheme proposed, we rigorously evaluate its security performance using Tamarin Prover and quantify the handover latency relying on OMNeT++ 6.0. It is verified that the scheme proposed is capable of effectively safeguarding station identity information during the handover process, while simultaneously reducing the handover latency.