High-throughput And Low-delay Data Delivery Schemes For Battery-free Wireless Sensor Network

Battery-free wireless sensor network(BF-WSN)emerges as a new solution for coping with energy shortage in battery-powered wireless sensor network(WSN).The battery-free sensor node could harvest energy from energy source,sense interested data and send the information to sink node.It is essential to design proper data delivery schemes to maximize the throughput and minimize delay in BF-WSN,such data delivery schemes should accord with the law of available energy in capacitor or rechargeable battery.In order to optimize throughput and average packet delay in single-hop wireless link,we aim to develop data delivery schemes based on IEEE 802.15.4 standard,which concern three variables: data rate,maximum transmission trial and data packet size.The main work and innovations are as follows:(1)We consider point to point communication scenario,according to the impact of link qu--ality,data packet retransmission and residual energy for link throughput,firstly,truncated geometric distribution and expected packet delay is defined in terms of packet retransmission.Secondly,we derive the throughout maximization problem and get the optimal data transmission rate,maximum transmission trial and data packet size by exhaustive search.Then,we propose optimal throughput data delivery scheme OSR(Optimal Packet Size,Data Rate and Maximum Transmission Trial)and present the specific procedure of OSR.(2)On the basis of throughput optimization,delay due to extra period for harvesting energy affects the total average delay,therefore we derive the closed form for average packet delay and formulate average delay minimization problem in point to point network which takes discrete data rate and maximum transmission trial as optimal variables.By solving the equation,we propose the average delay minimization data delivery scheme ORK(Optimal Data Rate and Maximum Transmission Trial)and present the procedure of ORK.Meanwhile,we model the data buffer in node as a queue and analyze the buffer overflow probability of battery-free sensor node.To verify the performance of OSR and ORK schemes,we compare our schemes with the FDR schemes which possess fixed data rate,fixed packet size and fixed transmission trial.The simulation results show that the OSR and ORK schemes can achieve better performance.