Wireless Communication Timeliness Estimation Method Based On Finite-order Moment

Driven by the demand for time-sensitive information in the Internet of Things(Io T),a lot of real-time applications generate huge amounts of real-time data that is sent over the network to processors for analysis to make decisions.The data generated by real-time Io T-based applications is not only diverse and voluminous,but also depreciates in value once the messages become stale.Therefore,message delivery schemes must be based on the fundamental need for timeliness.The inability of traditional metrics to meet the timeliness requirements of real-time applications has stimulated the emergence of a new metric,the Age of Information(AoI).So far,the potential of AoI as a key performance metric has been recognized in relevant theoretical studies and practical applications,and has shown a trend to gradually replace traditional metrics.However,the complex theoretical analysis and high practical energy consumption of AoI limit its further development and application.In this paper,with the premise of improving the timeliness of Io T communication and the goal of measuring system timeliness in an easy and energy-efficient way,innovative work is carried out in the following three parts.(1)Two types of transmission schemes are designed respectively for the node energy limitation and communication timeliness problems in wireless Io T real-time applications: continuous transmission schemes based on random sensing and discrete transmission schemes based on timely arrival.The first scheme serves data where the update rate can be sacrificed for overall freshness(e.g.,business class messages);the second scheme serves data where reliable and timely arrival is required seriously(e.g.,control class messages).In addition,by further considering system models for these two types of schemes and obtaining the corresponding queuing models,closed-form expressions for the age of information are derived for both schemes,and the correctness of the theoretical analysis is finally verified by experiments.(2)To address the problem that the theoretical analysis of AoI is difficult and expensive in practice,a class of wireless communication timeliness estimation methods based on finite-order moments to obtain information age is proposed by combining moment theory and practical communication requirements,and the method is successfully applied to the timeliness estimation of random sensing-based continuous transmission scheme and just-in-time arrival-based discrete transmission scheme.It is worth mentioning that the method is simple in its theoretical assumptions and does not require each packet to carry timestamps,which solves the main problems in traditional AoI analysis and practice.The method is not only applicable to the proposed two schemes,but also can be used for the timeliness estimation of various types of networks such as point-to-point networks,multi-source nodes networks,and multi-servers networks.(3)For the estimation method of wireless communication timeliness based on finite order moments,the estimation error bounds of the method are analyzed and the corresponding upper and lower error bounds are obtained.The results show that the estimation method has the best estimation effect when the arrival interval or service time follows the degenerate distribution with a given expectation,and the worst estimation effect when the arrival interval or service time follows the two-point distribution with the taken values lying on the left and right boundaries.And even in the worst case,the effect of the estimation method is still considerable.