30 November 2011 | http://hdl.handle.net/10773/8614
Recently, a focus by the research teams has been the conception and inclusion of intelligent systems in road tra c. Called Intelligent Transportation Systems (ITS), they are intended to minimize the time lost in congestion, energy consumption and environmental, human and material damage, thus trying to contribute to the sustainability of the setor. One of the known examples is the Electronic Fee Collection (EFC). EFC uses Dedicated Short-Range Communications (DSRC). Currently, there are some issues that need to be achieved to the efective development of these systems. Because we are dealing with systems that have constant evolution, new technologies are needed for design of these terminals that make possible to be frequently updated. The best solution to meet such requirements is to use Software Defined Radio (SDR), that is, handle the radio signals as much as possible by digital domain and, eventually, using software.
This dissertation aims to develop part of a BPSK receiver for DSRC using SDR. The radio receiver includes conversion of received signals from analog to digital and then the demodulation in FPGA. Therefore, it is initially made a presentation of communications involving DSRC standards at European level, such as the advantages of using SDR in this project. For the conceptualization of the project to be implemented, they are studied and simulated some of the most important architectures in the reception of BPSK signals. Analyzing the advantages and disadvantages of each one, the chosen demodulation method for the implementation was the Costas loop. Next, it is made a detailed presentation of the two main modules of receiver implementation: the construction of the amplification, filtering and analog to digital conversion board, and the realization of BPSK demodulator in FPGA. In a last phase, using validation and evaluation tests, several results are presented that illustrate the operation of the system. It was concluded that the receiver can demodulate the received signals. The dissertation ends with some suggestions for a maybe future evolution of the equipment.