Usage of a Software Defined Radio for the development of a portable GSM base station to detect trapped and buried people in ruins and avalanches
Guillermo Sánchez Martínez · 2014
Nowadays, avalanches, earthquakes and collapsed buildings are claiming an increasing death toll due to urbanisation, climate change and tourism, which means a harder work is required from Search and Rescue (SAR) operations. Despite this claim, SAR operations are still very limited and expensive, due to numerous constraints. RESCUECELL is a European Commission funded project, that will take advantage of the fact that nowadays most of the victims of this kind of accidents carry mobile phones with them, to develop an accurate location system based on mobile signal measurements, in order to create a cost-effective and portable kit for emergency search services, which will be easy to install and use. The aim of this thesis is to study, develop, and test the implementation of a portable GSM Base Transceiver Station (BTS) for the RESCUECELL system. This master node is called Control Centre (CC) and will be in charge of communicating with the buried GSM phones and locating them through captured mobile signals with the help of GSM sniffers, called Femtocell Access Points (FAPs) in this project, disposed within the disaster zone. GSM architecture involves a lot of highly expensive infrastructure, which would certainly not fulfill the requirements. The challenge of implementing it in a portable kit, easy to be transported by the rescue team, is faced in this thesis. Such implementation will be able to serve all the terminals within the disaster area, independently of the operator, and provide emergency and normal call support. Furthermore, cell selection and reselection procedures followed by Mobile Terminals (MTs) are studied, both for the technology chosen (GSM) as for other coexisting technologies (i.e. UMTS and LTE), in order to present an optimal cell setup that will enable the cell broadcasted by RESCUECELL CC to appear as the most attractive cell for the MTs in the affected area to attach to, in the presence of other competing cells, whether they are GSM, or other technology cells. Finally, CC-FAP communication is also studied and tested through GPRS communication, allowing the FAPs communicate the phones' signal properties (RSSI and ToA) to the CC and hence to locate them. In conclusion, this thesis presents the hardware and software used, procedures followed, requirements needed, optimal configuration, and developed code, in order to create a portable system that can make all phones in the affected area attach to the cell operated by RESCUECELL CC, and communicate with it, in order to permit the FAPs calculate their signal properties, and communicate them to the RESCUECELL CC leading to the phones' location.