What is Human Body Sensor Network? Introduction to Human Body Sensor Network

Body sensor network: BSN for short. BSN is body-centered and integrates multidisciplinary knowledge such as biosensors, medical electronics, multi-sensor analysis and data fusion, artificial intelligence, ubiquitous sensing, wireless communications and other innovative applications.

　　BSN gives full play to the advantages of wireless, networking and information technology to achieve tracking and service of the entire health process, and is one of the development directions of low-cost health.

　　The main features of BSN are data collection and interconnection.

　　Background of Human Body Sensor Network

　　As the concept of "prevention first" has gained popularity, remote collection and processing of health information is an essential means for early detection, early diagnosis and early intervention; secondly, in order to achieve continuous monitoring without affecting normal physiological activities, traditional wired systems are gradually becoming wireless; thirdly, as monitoring equipment develops towards microscale and long-term spans, innovative sensing methods and means are essential. In view of this, the human body sensor network came into being under the background of the Internet of Things, becoming the "tip" of the medical Internet of Things and the ubiquitous network (note: a widely existing network), helping to solve health and informationization.

　　Research Hotspots of Human Body Sensor Networks

　　Focusing on the research hotspots of BSN, the industry has carried out corresponding scientific research and industrialization work, which can be generally reflected in the following aspects:

　　(1) In terms of sensors, research and develop new sensing technologies such as electronic fabrics and non-contact electrodes;

　　(2) Experimental work has begun in energy harvesting, that is, using the human body's own mechanical motion energy or temperature gradient energy to power BSN nodes.

　　(3) Conduct research on BSN semantic models, focusing on the application of mathematical tools such as STSOM and Bayesian networks;

　　(4) Using single crystal integration, develop low-frequency, low-noise, and low-power medical integrated circuit chips suitable for BSN;

　　(5) In the area of ​​wireless communications, we focus on the exploration of the mechanism and technology development of the transmission mode using human body communication;

　　Module composition of human body sensor network

　　(1) Micro antenna, base station board, wireless charging and other functional modules;

　　(2) Physiological parameter measurement nodes such as respiration, ECG, blood oxygen, and pulse rate;

　　(3) A nine-degree-of-freedom inertial measurement node integrating acceleration, angular velocity, and magnetometers;

　　In general, the hardware system is characterized by miniaturization, low power consumption and low cost.

　　The human body sensor network software development kit (SDK) includes: development board software, wireless communication protocol, baseband design and data interface definition. Main technical indicators: wireless transmission data 50kbps; data transmission rate 10kbps; interconnection protocol. The BSN communication protocol is shown in the figure:

　　Analysis of key technologies of human body sensor network

　　BSN involves key technologies such as medical integrated circuit chips, IP modules and human body communications.

　　Medical integrated circuit chips and IP modules

　　Integrated circuit design has breakthrough technical advantages such as full integration, low power consumption, low cost, high performance, configurability and miniaturized medical integrated circuit chips.

　　The third-generation human body sensor network development platform adopts a low-frequency, low-noise, and low-power ("three lows") design method, and integrates multiple vital sign signal amplification, filtering, processing, and power management functions on a single crystal. The third-generation human body sensor network development platform is shown in the following figure:

　　Human body communication

　　Traditional communication theory regards the human body as an interference source. In BSN, in order to achieve low-load and high-reliability life information extraction, it is necessary to regard the human body as a transmission medium and study the information transmission mechanism of the human body channel.

　　A large number of in vivo experiments and numerical simulations were carried out in a "real floating" environment, clarifying factors such as carrier frequency (30MHz), modulation method and data rate (BPSK, 1-10MSps), energy consumption parameters (1nJ/bit), transmission distance and security (Capacitive Coupling , 1m), tissue-channel relationship, movement-channel relationship, and interaction between vital sign parameters and channels, providing a theoretical basis for the study of the communication mechanism of the next-generation BSN.

　　Research on the occurrence and development mechanism of cardiovascular and cerebrovascular events requires multimodal health information such as imaging, biochemistry, genes, and vital signs. Among them, dynamic detection of vital information is particularly closely related to the evaluation of cardiovascular and cerebrovascular function, as shown in:

　　(1) Dynamic changes in blood pressure are an important inducing factor leading to the shedding of vulnerable plaques;

　　(2) ST-T segment electrocardiogram abnormality is an important indicator for the early diagnosis of coronary heart disease;

　　(3) Heart rate variability is an important factor in predicting the occurrence and persistence of arrhythmias;

　　(4) Abnormal nocturnal respiratory rate is an important risk factor for events such as COPD;

　　(5) Daytime movement information is an important means to assess the prognosis of hemiplegia caused by stroke.