Efficient Data Collection And Secure Authentication Towards Low Power IoT

For the Internet-of-Things(IoT)systems,wireless sensor networks work as the interface to the physical environment,providing lots of sensing data.For intertidal zones,considering the special environmental conditions,the deployed wireless sensor networks suffer from the unstable data connection,long data transmission latency,and high sensor energy consumption.To address these problems,this thesis analyzes the low power configuration for sensors nodes,and proposes new routing algorithms with low power consumption and low data transmission latency.·To prolong battery lifetime,a "duty-cycle mode" is utilized in many wireless sensor networks.In duty-cycle mode,the device can be in two seprate phases:the active phase,which transmits packets,and the sleep phase where the microcontroller units(MCUs)work in low-power mode and no packets are transmitted.Prior researches mainly focus on energy efficiency in the active phase,and energy consumption during the sleep phase is generally ignored as it is assumed to have little margin to be optimized.However,in this work,we reveal that sleep phase can become a significant battery consumer due to the mis-configuration of General-Purpose Input/Output(GPIO)pins of MCUs.We propose OPCIO,which incorporates a genetic algorithm to obtain energy-efficient GPIO configurations automatically to reduce the energy waste during the sleep phase.We prototype OPCIO on off-the-shelf devices and evaluate it on two Arm devices.Experiment results show that OPCIO can effectively find multiple low power configurations that prolong the lifespans in a hardware aspect.·To sustain reliable data delivery in dynamic environments,a link quality estimation mech-anism is crucial.However,our observations in two real intertidal wireless sensor networks reveal that the link update in routing protocols often suffers from energy and bandwidth waste due to the frequent link quality measurements and updates.In this thesis,we investigate the network dynamics using real-world network data and find it feasible to achieve accurate estimation of link quality using sparse sampling.We design and implement a compressive-sensing-based link quality estimation protocol,LESS,which incorporates both spatial and temporal characteristics of the system to aid the link update in routing protocols.We evalu-ate LESS in both real systems and a large-scale simulation.The results show that LESS can reduce energy and bandwidth consumption by up to 50%while still achieving more than 90%link quality estimation accuracy.·Intertidal areas are among the harshest environments for the network deployment,and in-tertidal networks show significant higher delays when compared with other wireless sensor networks.In this thesis,we model and analyze the different causes of delays in intertidal networks,and find it feasible to decrease the end-to-end delay with a node state associated routing protocol.To this end.we design a lightweight hidden markov model(HMM)based node current state predictor and a machine learning based node future state predictor.Com-bining link quality and node state for routing path selection,we propose delay-oriented rout-ing protocols SADO and PIDO for different network scenarios.We evaluate the performance of SADO and PIDO in large-scale simulations.The results demonstrate that SADO and PIDO can decrease the end-to-end delay significantly with limited overhead.Besides,considering the extensive usage of short-range device-to-device(D2D)communica-tion,we explore the authentication mechanism of smart devices.·In D2D communications,a critical security problem is verifying the legitimacy of devices when they share no common information in advance.Based on this,we present NAuth,a nonlinearity-enhanced,location-sensitive authentication mechanism for such communica-tion.NAuth contains a verification scheme based on the nonlinear distortion of speaker-microphone systems and a location-based validation model.The verification scheme guar-antees device authentication consistency by extracting acoustic nonlinearity patterns while the validation model ensures device legitimacy by measuring the time difference of arrival at two microphones.We theoretically analyze the security of NAuth and evaluate its perfor-mance experimentally.Results show that NAuth can verify the device's legitimacy in the presence of nearby attackers.