All digital ambient Backscatter

• Autor(a) principal: Torres, Ricardo Miguel André
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/30688
• topic: Ambient backscatter communication; Software defined radio; Low power communication

We live in an era where the need to monitor our surroundings is a crucial aspect in daily life. Many examples can be given, which originated the concepts of smart cities, smart farms and other \smart" things. The scaling up of these devices from a few million to many billions originated a new area of interest which focus on the optimization of how monitoring devices transmit information. The traditional approach was to use an active radio for each device, but due to the high power consumption and cost requirement a new wave of backscatter radios has been under development. The most common architecture for backscatter radios is based in analog circuits however, it is also possible to use an all-digital approach which is not widely used. During this work, different kinds of Microcontroller Unit (MCU) were tested in order to measure and study their response when exposed to electromagnetic waves. Even though not all MCU are suitable for all-digital backscatter, many of them proved to be good solutions to implement this technology. Besides the all-digital approach, this work also focus on ambient backscatter. It consists in reusing electromagnetic waves such as Frequency Modulated (FM) radio signals, which after some tests proved to be the most suitable for this application. In a glance, this work presents an all-digital ambient backscatter system, considering the use of FM waves, the development of an all-digital backscatter tag, and a receiver based on SDR. The final results show that the developed devices are able to receive, modulate, transmit, demodulate and process data.