Research On Optimization Of Multi-point Wireless Body Area Network Based On Age Of Information

With the aging of the world population and the accelerated industrialization of society,the incidence of various chronic diseases is gradually increasing,and the requirement for health monitoring systems is rising.The human body-centered wireless body area network(WBAN),which is composed of sensor nodes located in different parts of the human body with different functions,has indicated tremendous application value in the healthcare field based on its characteristics of remotely monitoring various physiological parameters of the human body.The intelligent medical system based on WBAN can not only monitor the longterm vital signs of patients,effectively prevent diseases,but also send an alarm when patients have sudden diseases,so that patients can be treated in time,effectively improving the utilization of medical resources and reducing the time and money costs of patients.Due to its strong scalability,WBAN has also been widely used in military activities,leisure and entertainment,sports training and other fields besides health care.In wireless networks,the timeliness of receiving information often decreases sharply with the passage of transmission time.At present,most studies use throughput and time delay as the measurement indicators of real-time information,but in the field of medical emergency,doctors have more accurate requirements for the real-time of patient monitoring information,and also need to ensure the diversity and accuracy of sampling information,so that doctors can reasonably formulate treatment plans.In addition,energy efficiency has always been a problem that WBAN needs to overcome.The energy required by the sensor usually comes from its own battery.Due to the limitation of capacity and volume,the battery needs to be replaced regularly.This will not only interrupt the transmission of information,but also cause harm to human body by changing the battery frequently for some sensors placed in the body.Energy Harvesting(EH)technology based on radio frequency(RF)signals can not only provide continuous and stable energy,extend the service life of the system network,but also transmit information to sensors while transmitting energy,improving energy utilization.In a multi-node wireless network,the system’s transmission power,transmission time slot,antenna and other resources are limited,which greatly restricted the system performance enhancement.Therefore,it is essential to establish a reasonable resource allocation scheme and an efficient node scheduling strategy.To address the above issues,this paper first uses an age penalty function based on age of information(Ao I)as an indicator to measure the freshness of information received by the system,and designs a transmission protocol based on a multi node WBAN transmission model.In order to optimize the timeliness of the system’s received information,a dynamic scheduling strategy based on Lyapunov drift plus penalty function is proposed,which is compared with the transmission scheduling algorithm,The optimality of the algorithm is verified;Secondly,based on the multi node model,the transmission model of classified multinode is constructed,and a single node dynamic scheduling algorithm based on drift plus penalty function is proposed according to the characteristics of the system model;Finally,the optimization algorithm is further improved.Based on TDMA(Time Division Multiple Access)technology,combined with orthogonal frequency division multiplexing(OFDM)technology,a multi-node dynamic scheduling algorithm is proposed,which optimizes the system time efficiency and improves the spectrum utilization.The main contributions of this paper can be summarized as follows:1.In view of the timeliness of the system receiving information,a multi-node WBAN energy and information bidirectional transmission model is designed.Combining wireless energy transmission technology to achieve resource allocation and optimization for downlink signal broadcasting,node scheduling and uplink update packet return,etc.A dynamic node scheduling algorithm is proposed to minimize the average age penalty function of the system.2.Aiming at the diversity and accuracy of sampling information,a bidirectional transmission model of WBAN based on classified multi-node is constructed,and a transmission protocol with mixed time allocation and power allocation is proposed.Lyapunov drift plus penalty function is applied to simplify the optimization problem of system timeliness,and single-node dynamic scheduling strategy and multi-node dynamic scheduling strategy based on drift plus penalty function are proposed respectively to improve the system timeliness.3.In view of the above scheduling strategy,for reducing the computational complexity,this study decomposes the optimization problem into two sub-problems: the maximization of transmission probability and the solution of the optimal scheduling decision.The convergence and optimality of the proposed algorithm are further proved by MATLAB simulation and comparison with random scheduling and sequential scheduling strategies.To sum up,this paper aims to study the resource allocation scheme and node scheduling strategy based on classified multi-node WBAN.Under the constraints of node average information age and transmission power,the system optimization problem is constructed to improve the timeliness of received information while ensuring the stability of the system,which provides a new idea for the follow-up research of wireless body area network.