An Optimized Method Based on Two-Layer PSO Algorithm for the Node Placement of the Wireless Ad Hoc Network in Train Autonomous Circumambulate System

Train autonomous circumambulate system (TACS) is a significant trend in urban rail transit system, which adopts both train-to-train and train-to-ground communication to transmit data in high throughput and low latency. A clustered Ad hoc network is proposed for TACS. Multiple paths of transmission can be established to increase the survivability and throughput of communication in TACS. The QoS of the communication is highly related to the placement of nodes in the ad hoc network. In this paper, a multi-object optimized node placement method based on the two-layer swarm optimization algorithm (TLPSO) is proposed. In the outer layer, the node interval in rows and the distance from the track are abstracted as particle positions to realize the regular placement of relay nodes. And in the inner layer, the gateway nodes are selected from the deployed relay nodes in the outer layer. The simulation results show that the network capacity of a cluster is 186Mbps, and the average latency is 14.53ms, which meets the Quality of Service (QoS) requirements of the TACS.