In-tunnel mobile communications deployment of an heterogeneous WLAN-WiMAX wireless network

Public transportation is vital in everyday life. As a consequence, the increasing need for intelligent surveillance systems over public transportation provides promising areas for wireless vehicular communication research for in-tunnel applications. This paper particularly emphasizes on tunnel implementation regarding to a prototype surveillance system on railway environments based on autonomous, smart monitoring devices that capture data only upon the occurrence of an incident, potentially dangerous for the passengers (like an explosion blast or the triggering of the fire detector). In this paper an attempt has been made to evaluate the performance of wireless vehicular communication inside a challenging tunnel environment after an emergency event. Due to the fact that extreme tunnel conditions (i.e. blind spots, intersymbol interference, NLOS) can cause major wireless network propagation failure, we develop a wireless hybrid network architecture consisted of IEEE 802.11b/g/e and IEEE 802.16e protocols. Furthermore this network was implemented in order to transmit the captured data from the monitoring devices of the train coaches to the Base Stations that are placed towards the metro stations. Finally, we use the OMNeT++ simulator tool for creating a simulation environment of the vehicular wireless network in order to compare the results with the experimental measurements.