Sistema de comunicación resiliente para escenarios de emergencia

Abstract

In emergency or rescue scenarios it is usually difficult to have a network infrastructure in place, especially in remote or geographically difficult-to-access locations. However, it is necessary to have tools to communicate or assess the situation. In this sense, ad hoc networks emerge as an option to solve this problem. Within the research project “IoT technologies and wireless sensor networks applied to structural health monitoring in essential buildings in the city of Cuenca”, a multi-hop ad hoc network was implemented in the main building of the Empresa Eléctrica Regional Centro Sur. In this context, this thesis work proposes the development of an emergency communication system for the transmission of multimedia traffic between the different floors of the building using the available ad hoc network. To this end, multiple experiments were carried out to determine the values of fundamental metrics (e.g. packet loss, delay, and throughput) for real-time audio and video transmission. Specifically, open source tools were developed to extract the required metrics and to objectively compare video quality using current encoding mechanisms (e.g. VP8, VP9, H.264, H.265). The results obtained determined VP8 as the most suitable codec for the proposed scenario. In addition, a videoconferencing tool was developed to measure the bandwidth available in the network and to select the appropriate bitrate to maintain an acceptable communication quality. The Real Time Transport Protocol (RTP) was used to transmit and synchronize audio and video streams. In addition, the Real Time Transport Control Protocol (RTCP) was used to measure metrics such as packet loss and delay using fields of this protocol present in the frames