Adaptive Aerial Cell Replacement Mechanism for Efficient Operation in 6G Wireless Networks

Low-altitude platform (LAP)-based aerial cells require frequent replacement due to periodic and aperiodic triggers, like low battery, variations in capacity demands, and mechanical malfunctions while in service. During a replacement event, the ongoing data sessions for all connected users should be transferred from the source LAP to the target LAP without interruptions. Protocols based on user handover and link management between the source and target LAPs are slow due to the overheads of signaling, causing a degradation in user data throughput during replacement. Recent literature on aerial cell cloning (ACC) proposes a much faster protocol by replicating link and location parameters from source to target LAP, but with the limitation that it is directly proportional to the number of user contexts. As a result, the latency and energy consumption for replacement are higher with increased users. Another recent scheme, dual active protocol stack (DAPS) handover, does not apply to aerial cell replacement scenarios due to high packet forwarding overhead. This paper, at the outset, proposes a novel low overhead aerial dual active protocol stack (aDAPS) handover with reduced packet forwarding, applicable to aerial cell replacement in ultra-reliability and low latency (URLLC) scenarios. Next, it proposes a novel adaptive aerial cell replacement (ACeR) mechanism. ACeR assists the network in selecting an appropriate session transfer protocol for each user based on predicted data traffic volume, traffic characteristics, and the trigger for the replacement. ACeR jointly optimizes the latency and energy optimality of the network. The system is modeled mathematically, and extensive system-level simulation results show that the proposed ACeR mechanism is efficient. ACeR reduces network energy consumption by up to 34.5% and around 14% to 18% on an average compared to the fixed protocol used during replacement in the available literature.