Detailed explanation of wearable wireless network technology solutions

3. Wearable wireless network core technology

　　Although wireless LAN technology is relatively mature and can be used as the basis for developing wearable wireless networks, it still needs to solve a number of key problems to truly apply it to wearable wireless networks. These problems focus on the core technologies of wearable wireless networks, which are mainly manifested in the following aspects:

　　3.1 Network Design

　　Network design must first ensure the system functions and network stability as much as possible. Compared with wired technology, wearable networks using wireless technology have greater flexibility in networking.

　　In addition, network design should also take into account human body shape and behavior. A good network structure should be easy to wear, comfortable, light, easy to carry, and have a certain degree of shock resistance. At the same time, the network structure should be as simple as possible and easy to use (especially for operation and reading services).

　　3.2 Input and Output Devices

　　Input and output devices are important interfaces for realizing human-computer interaction in wearable wireless networks. The flexibility and convenience of human-computer interaction will not only affect the full play of system functions, but also affect its promotion and application in the market.

　　Input devices include handwriting tablets, keyboards, microphones and other devices controlled by people, as well as special data input devices such as cameras, GPS, sensors, etc. In addition to realizing voice and data input, input devices should also be able to meet control requirements; output devices include headphones, display devices and touch devices. Output devices should not only provide information services to users, but also reflect the will and requirements of users. Of course, the input and output devices required for different applications are not necessarily the same, and should be configured according to actual needs.

　　3.3 Multifunctional integrated device

　　It should be said that most of the devices with specific functions that meet the needs of wearable wireless networks are already available on the market, and some functions have been integrated, such as headsets, touch screens, etc. However, most of these devices do not have wireless interfaces, so they need to be integrated and redesigned on the shell to meet the needs of human wear. For devices that play multiple roles in the network, the need for multi-functional integration is more urgent and more important. For example, a mobile phone as a gateway should not only have various functions of a mobile phone, but also be responsible for managing the entire wearable wireless network and forwarding data, which is obviously challenging.

　　The higher the integration of multifunctional integrated devices and the more miniaturized the equipment, the better they can meet the needs of wearable wireless networks. Of course, this depends on the further development of ultra-large-scale integrated circuits.

　　3.4 Operating Platform

　　In response to the requirements of wearable wireless networks, an operating platform corresponding to its hardware devices should be provided. The operating platform can also be developed according to specific application requirements, but they should have basic management services to ensure the stable operation of the entire network. Generally speaking, we can directly refer to the handheld OS currently used on mobile terminals such as mobile phones, and further develop on this basis; we can also use Linux to develop a dedicated OS. The former method will obviously help shorten the development cycle and reuse existing application software, but its disadvantage is limited functions; the latter method can be highly targeted, but its disadvantage is that there is no corresponding application software support and it is more difficult to develop.

　　3.5 Network survivability

　　The survivability of a network is reflected in its ability to adapt to the surrounding environment. It is mainly manifested in two aspects: the reliability and stability of the network connection and the anti-interference ability of the network. The survivability of a network largely determines the quality of service (QoS) of the network. As can be seen from Table 1-1, both Bluetooth and ZigBee technologies have some technical measures to enhance environmental adaptability. For example, in terms of anti-interference, ZigBee and Bluetooth use DSSS and FHSS technologies respectively; in terms of error correction mechanism, Bluetooth and ZigBee use forward error correction mechanism and error detection/retransmission mechanism respectively. However, due to the rapid increase in the number of wireless devices, the use environment of wireless devices has also deteriorated. In addition, they all work in the ISM frequency band, so it is necessary to study more reliable technical measures to ensure the survivability of the network.

　　3.6 Energy

　　For wearable wireless networks, devices in the network are usually powered by batteries. The average working time of a battery cycle depends on the battery capacity on the one hand, and on the energy consumption of the device and the efficiency of the power supply on the other hand.

　　At present, driven by large-scale integrated circuits, many electronic devices are developing in the direction of miniaturization and micro-miniaturization. In comparison, power supply technology has not made substantial progress, resulting in an increasing proportion of weight and volume of batteries in many mobile communication devices. Therefore, finding new alternative energy sources will be a significant topic.

　　At the current stage, when the device can only be powered by batteries, in addition to requiring users to develop good operating habits, the average working time of the battery can be improved from both hardware and software aspects. In terms of hardware, the integration of the device should be improved as much as possible, and new components should be used for energy-saving design to reduce the energy consumption of the device; in terms of software, reasonable device working modes and energy-saving modes should be designed, and corresponding algorithms should be developed to make the signal transmission power have adaptive characteristics.

　　3.7 Security

　　Security issues are also inherent in wireless networks. The premise for solving security issues is that users must have security awareness, followed by technical and management issues. Currently, many wireless networks provide security features such as authentication and encryption, but these measures alone are not enough! However, the increase in security measures will increase the operating burden of network equipment and reduce the operating efficiency of the network. This is the relationship between the spear and the shield.

　　The security issues related to wireless networks have been discussed in depth in many literatures and will not be repeated here.

4. Application of wearable wireless networks

　　Wearable wireless networks can be roughly understood as the implementation of wireless LAN technology on individuals (see Figure 4.1). It can be said that there are application requirements for wearable wireless networks in different fields.

　　4.1 Military Applications

　　The military field is one of the most promising application areas for wearable wireless networks, especially for military tasks such as intelligence search and reconnaissance behind enemy lines. For such applications, the system is usually required to be equipped with headsets, cameras, wearable GPS devices, and communication devices with display and storage functions, so that reconnaissance personnel can maintain communication with the outside world through the system, determine their own location, and conduct reconnaissance activities conveniently.

　　Figure 4.1 Schematic diagram of wearable wireless network applied to human body

　　4.2 Industrial Applications

　　In the field of industrial production, when factors such as the space environment cause many wired detection devices to be unable to operate normally, or when multiple detection devices need to work together and it is inconvenient to use wired connections, wearable wireless networks can be applied. This will not only bring convenience, but also enable timely acquisition, processing and transmission of data, thus improving detection results.

　　4.3 Healthcare and disability assistance

　　Another area that is attractive to wearable wireless networks is health care and assistance for the disabled. For example, multiple sensors or other medical devices can be placed on the patient (the sensors can also be placed inside the patient's body as needed) to detect the patient's vital signs; for patients who do not need hospitalization but need to observe their condition at any time, a certain number of sensors can also be placed on the patient, and the data sent by the wireless network can be used to keep abreast of the patient's latest condition. For the disabled, they can obtain information about the user or the surrounding environment through various devices on the wearable wireless network, and then provide help or warning information (voice or image) according to the specific situation.

　　4.4 Daily life applications

　　In real life, many people actually carry multiple terminals at the same time. If these terminals are connected by wearable wireless network, it will bring a lot of convenience. For example, you can download music recommended by friends through your mobile phone in time, and then transfer it to your own MP3 to enjoy.

　　Wearable wireless networks can also bring convenience or provide safety to travel adventurers, and so on.