Research On Optimization And Scheduling Of Resources In WBAN

With the popularization of Internet of things applications,the data transmission requirements of WBAN are increasing accordingly,which puts forward higher requirements for its network performance.The performance of WBAN mainly depends on the quality of service and energy efficiency.Existing researches have a lot of shortcomings in the above two aspects.When a large number of heterogeneous sensor nodes access the channel at the same time or the channel quality is extremely bad,the network performance is very poor.In addition,the protocol interaction process adopted in some studies also has room for further optimization.This thesis makes an in-depth analysis of the above problems and proposes corresponding solutions.The main contents and innovations of this thesis are as follows:(1)For the problem of low performance caused by multiple heterogeneous sensor nodes accessing channels,this thesis proposes a priority-based MAC protocol with HighPerformance Design.Firstly,the node priority is carefully designed according to the importance degree,sampling rate,timeout condition and remaining energy.Then,considering the priority of the node and the channel factors,a utility function is introduced to characterize the value of a node transmitting data frames in a specific time period.Next,the author models the time slot allocation problem,where the objective is to maximize the total utility of the data transmission of all nodes in a specified period of time by adjusting the transmission start time and the transmission duration of each node.Finally,according to the problem model,the author proposes a time slot allocation scheme based on a greedy strategy,which effectively reduces the time complexity of the direct solution to the problem.In this scheme,nodes with higher priority are arranged to transmit data frames in the time slots with better channel conditions.This scheme has good performance in average delivery probability,delay characteristic,energy efficiency and scalability,and its advantage is more obvious when the number the sensor nodes is larger.(2)For the transmission performance degradation caused by excessively long sleep delay and poor channel quality,this thesis proposes the optimization method for the sampling start time and the data frame length of the sensor nodes based on the slot allocation scheme proposed in the first point.The design of sampling start time comprehensively takes into account the sampling rate,sampling time,transmission rate and other factors,and arranges the appropriate sampling time for the nodes through the quantitative analysis of the relationship between several factors,which greatly reduces the waiting time delay of the nodes.In the design of data frame length,the relationship between the optimal data frame length and the average delivery probability is analyzed quantitatively considering the channel model,and the performance of the scheme is analyzed.This scheme further improves the network performance,delivery probability,delay characteristics and energy efficiency.When the channel conditions of nodes are worse,i.e.,the average delivery probability is lower,its advantages are more obvious.