Research And Implementation Of Packet Aggregation Method In 6TiSCH Network

6TiSCH(IPv6 over TSCH Mode of IEEE 802.15.4e)technology greatly improves the communication real-time and reliability of IPv6 wireless sensor network by introducing slot hop channel mechanism,and has been widely concerned and recognized in the field of industrial wireless communication.Packet aggregation is usually used in wireless sensor networks to improve network transmission efficiency and reduce network congestion.It is of great significance to realize network load balancing and prolong network life time.However,due to the use of slot hop channel mechanism and IPv6 network protocol stack architecture in 6TiSCH network,the traditional packet aggregation method of wireless sensor network cannot be directly applicable to 6TiSCH network.Therefore,this thesis studies how to introduce the functions of packet aggregation and deaggregation into6 TiSCH network to improve the transmission efficiency and reduce the transmission delay.The main work includes:1.The key technologies of packet aggregation in 6TiSCH network are studied,including 6TiSCH protocol stack,6TiSCH scheduling technology and key technologies of packet aggregation in wireless sensor network.2.6TiSCH network data packets for when there is a lot of redundant data,we design a lossless packets polymerization and depolymerization method,including identification of the aggregated data packets method,condition of depolymerization of the packet polymerization method and polymerization method,and made for different types of6 TiSCH packet polymerization and depolymerization processes,improve the efficiency of program execution.3.In order to reduce the delay of packet transmission to the sink node,an aggregation tree construction method based on delay is designed.Four constraints are proposed to construct the aggregation tree: scheduling wait time,Rank value,aggregate length of packets,and channel not occupied.The multi-slot frame structure of scheduling algorithm is designed,and a method is proposed to improve slot reuse rate and avoid scheduling conflicts while selecting scheduling elements with the shortest scheduling waiting time.4.The packet aggregation method under 6TiSCH network proposed in this thesis is realized based on Contiki-NG operating system,and the simulation analysis of the proposed method is carried out by building an experimental platform through Cooja.The simulation results show that the proposed method can effectively reduce the amount of redundant data in the network,and is compatible with different types of 6TiSCH packets.The aggregation tree construction method proposed in this thesis can effectively reduce the delay of packet aggregation,and the method designed to screen scheduling units with the shortest scheduling wait time can effectively improve the time slot reuse rate and avoid conflicts.The research work in this thesis satisfies the requirement of packet aggregation function under 6TiSCH network and has high reference value for improving and enhancing the performance of 6TiSCH network.