IoT term is used to refer to - the resulting globlal network of connecting smart objects - the protocols ... - ... required features: - devices hetereogeneity - scalability - data ubiquitous data exchange - energy-optimized solutions #### Backscattering - allows devices to run without battery - only available at research level for now - use radio frequency signals as power source - two types - ambient - rfid ##### Ambient backscattering - devices harvest power from signals available in the environment - they use existing RF signals without requiring any additional - Performance drawbacks - low data rate (about 1kbps) - not suitable for real-time applications that continuously exchange data - availability of signals - signal may not be available indoor or not powerful enough ##### RFID backscattering ... ##### Battery free smart home - in a smart home there may be a lot of smart devices - if every one of them has a battery, it's not good for the environment - we can deploy an RFID reader with multiple antennas that covers all the different rooms ### Communication add scheme slide RFID tags run EPC Global Standard - in a smart home we may want less bits dedicated to the tag id and more dedicated to the actual data - 8 bits for ID - 6 bits for data - 4 for CRC ### Infrastructure based wireless networks - base stations connected to wired backbone network - stations choses the closest base station - Limits - when no infrastructure is available - expensive/inconvenient to setup - when there is no time to set it up