Range And Interference Analysis For Battery-less Sensors In Backscatter Communication Networks

The Internet of Things(IoT)is the network of physical objects or "things"embedded with electronics,software,sensors,and network connectivity,which enables these objects to collect and exchange data.IoT allows objects to be sensed and controlled remotely across existing network infrastructure,creating opportunities for more direct integration between the physical world and computer-based systems,and resulting in improved efficiency,accuracy,and economic benefit.With the growth of the Internet of Things(IoT),there is a rising need for energy efficient wireless communication methods.The obstacles of inadequate battery power motivate researchers to exploit Radio Frequency(RF)signals as the energy source for battery-less sensors communications networks.Ambient backscatter communication makes it possible to harvest energy from incident RF signals and reflect back parts of the same signals while modulating the data.Ambient backscatter communication permits small devices(e.g.,sensors,tags)to compute and communicate with each other by using only the power they harvest from radio frequency signals.This system utilises existing ambient RF radiations as the source of power and for communication between devices.It makes use of ambient RF signals such as TV broadcast signals,mobile communication signals,and Wi-Fi.For all such applications,ambient backscatter does not require a separate power source to operate.The key idea of ambient backscatter is that the tags or sensors will reflect the existing signals or not to represent 1 or 0 bit,and the reader can differentiate the two states,i.e.,reflecting or non-reflecting,via some detection algorithms.Although ambient backscatter communication has great potential for future low-energy communication systems,especially Internet-of-Things(IoT),it is still facing many challenges.One crucial issue for ambient backscatter is interference on backscatter communication networks.The goal of this dissertation is to inspect this problem theoretically and experimentally.The theoretical system model for the ambient backscatter systems is presented in this thesis.A Maximum Likelihood(ML)detector is used for signals detection.Lastly,evaluations of interference on ambient backscatter communication systems via simulations are provided.It has been shown that the distances and angles between the radio frequency source,the tag,and the reader will affect the bit error rate(BER)performance.