Wireless sensor network standardization progress and protocol analysis

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As an application-oriented research field, wireless sensor networks have achieved rapid development in recent years. In terms of the research and development of key technologies, the academic community has carried out a lot of research in network protocols, data fusion, test and measurement, operating systems, service quality, node positioning, time synchronization, etc., and achieved fruitful results; the industry is also exploring applications in environmental monitoring, military target tracking, smart homes, automatic meter reading, lighting control, building health monitoring, power line monitoring and other fields. With the promotion of applications, wireless sensor network technology has begun to expose more and more problems. Equipment from different manufacturers needs to be interconnected and avoid mutual interference with the current system. Therefore, different chip manufacturers, solution providers, product providers and related equipment providers are required to reach a certain understanding and work together to achieve the goal. This is the background of the standardization of wireless sensor networks. In fact, since standardization work is related to the economic interests and even social interests of multiple parties, it is often generally valued by related industries. How to coordinate the interests of all parties and reach a consensus requires sufficient understanding and patience from all parties involved.

So far, the standardization of wireless sensor networks has received widespread attention from many countries and international standard organizations, and a series of drafts and even standard specifications have been completed. The most famous of these is the IEEE 802.15.4/zigbee specification, which has even been regarded as a standard by some researchers and industry professionals. IEEE 802.15.4 defines the physical layer and link layer specifications for short-range wireless communications, while zigbee defines network interconnection, transmission and application specifications. Although the IEEE802.15.4 and zigbee protocols have been launched for many years, with the promotion of applications and the development of the industry, their basic protocol content can no longer fully meet the needs. In addition, the protocol only defines the content of network communication and does not propose a standard protocol interface for sensor components, so it is difficult to carry the dream and mission of wireless sensor network technology; in addition, when the standard is implemented in different countries, it must be subject to the current standards of the country and region. For this reason, people began to launch more versions based on the IEEE 802.15.4/zigbee protocol to adapt to different applications, different countries and regions.

Despite its imperfections, IEEE 802.15.4/zigbee is still the best combination for the development of wireless sensor network technology in the industry. This article will focus on the IEEE 802.15.4/zigbee protocol specifications, and appropriately take into account other relevant standards of sensor network technology. Of course, the standardization of wireless sensor networks has a long way to go: first, wireless sensor networks are still an emerging field after all, and their research and applications are still quite young, and the needs of the industry are still unclear; second, IEEE 802.15/zigbee is not tailored for wireless sensor networks, and some problems need to be further solved when used in wireless sensor network environments; in addition, the international standardization work specifically for wireless sensor network technology has just begun, and the domestic standardization working group has just been established. To this end, we must make full preparations for the smooth completion of standardization work.

1. PHY/MAC layer standards

The underlying standards of wireless sensor networks generally follow the relevant standard parts of wireless personal area networks (IEEE 802.15). Wireless personal area networks (WPANs) appeared earlier than sensor networks and are usually defined as wireless short-range dedicated networks that provide interconnection between personal and consumer electronic devices. Wireless personal area networks focus on two-way communication technology issues between portable mobile devices (such as personal computers, peripherals, PDAs, mobile phones, digital products and other consumer electronic devices), and their typical coverage range is generally within 10 meters. The IEEE 802.15 working group was specially set up to accomplish this mission, and has completed the formulation of a series of related standards, including the underlying standard IEEE 802.15.4, which is widely used in sensor networks.

(1) IEEE 802.15.4b specification

The IEEE 802.15.4 standard is mainly formulated for low-rate wireless personal area networks (LR-WPAN). The standard focuses on low energy consumption, low-speed transmission, and low cost (which is consistent with wireless sensor networks), and aims to provide a unified interface for low-speed interconnection between different devices within an individual or home. Since the characteristics of the LR-WPAN network defined by IEEE 802.15.4 have many similarities with the intra-cluster communication of wireless sensor networks, many research institutions use it as the physical and link layer communication standard for sensor network nodes.

The IEEE 802.15.4 standard defines the physical layer and the media access control sublayer, which conforms to the Open Systems Interconnection model (OSI). The physical layer includes the RF transceiver and the underlying control module, and the media access control sublayer provides a service interface for the upper layer to access the physical channel. Figure 1 shows the relationship between the IEEE 802.15.4 layers and the IEEE 802.15.4/zigbee protocol architecture.

IEEE 802.15.4 is designed for low cost and higher level integration in the physical (PHY) layer. The operating frequencies used are 868MHz, 915MHz and 2.4GHz. The number of available channels in each frequency band is 1, 10 and 16 respectively. Each frequency band provides a transmission rate of 20kb/s, 40kb/s and 250kb/s, and the transmission range is between 10 meters and 100 meters. Since the three frequency bands used in the specification are the ISM (Industrial Scientific and Medical) open frequency bands defined by the International Telecommunication Union Telecommunication Standardization Sector (ITUT) for scientific research and medical treatment, they are widely used by various wireless communication systems. In order to reduce interference between systems, the protocol stipulates that direct sequence spread spectrum (DSSS) coding technology is used in each frequency band. Compared with other digital coding methods, direct sequence spread spectrum technology can simplify the analog circuit design of the physical layer and has higher fault tolerance performance, which is suitable for the implementation of low-end systems.

IEEE 802.15.4 defines two access modes in the media access control layer. One is Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). This mode refers to the DCF mode defined in the IEEE802.11 standard in the wireless local area network (WLAN), and is easy to achieve channel-level coexistence with the wireless local area network (WLAN, Wireless LAN). The so-called CSMA/CA is to first listen to whether there is a co-channel carrier in the medium before transmission. If not, it means that the channel is idle and will directly enter the data transmission state; if there is a carrier, the channel will be re-detected after a random backoff period. This media access control layer solution simplifies the process of implementing self-organizing (Ad Hoc) network applications, but it brings trouble to improving bandwidth utilization in large-volume transmission applications; at the same time, because there is no power management design, more work needs to be done to implement low-power network applications based on the sleep mechanism.

Another communication mode defined by IEEE 802.15.4 is similar to the PCF mode defined by the 802.11 standard. It improves channel utilization by using a synchronized superframe mechanism and easily achieves low power consumption control by defining a sleep period within a superframe. The PCF mode defines two types of devices: Full-Function Device (FFD) and Reduced-Function Device (RFD). FFD devices support all 49 basic parameters, while RFD devices are only required to support 38 basic parameters in the minimum configuration. In the PCF mode, the FFD device acts as a coordinator to control the synchronization and data transmission and reception process of all associated RFD devices, and can communicate with any device in the network. The RFD device can only communicate with the FFD device associated with it. In the PCF mode, there is at least one FFD device in an IEEE 802.15.4 network as a network coordinator (PAN Coordinator), which plays the role of the network master controller and is responsible for tasks such as inter-cluster and intra-cluster synchronization, packet forwarding, network establishment, and member management.

The IEEE 802.15.4 standard supports two network topologies: star and point-to-point, and has two address formats: 16-bit and 64-bit. The 64-bit address is a globally unique extended address, and the 16-bit segment address is used to build a small network or as an identification address for devices within a cluster. The IEEE 802.15.4b standard has multiple variants, including the low-speed ultra-wideband IEEE 802.15.4a, the IEEE 802.15.4c and IEEE 802.15.4e that China is currently promoting, and the IEEE 802.15.4d that Japan is mainly promoting. We will not discuss this in depth here.

(2) Bluetooth technology

In May 1998, shortly after the IEEE 802.15 Wireless Personal Area Network Working Group was established, five world-renowned IT companies: Ericsson, IBM, Intel, Nokia and Toshiba jointly announced a research and development plan called "Bluetooth". In July 1999, the Bluetooth Working Group launched the Bluetooth protocol version 1.0, which was updated to version 1.1 in 2001, which is the IEEE 802.15.1 protocol we are familiar with. The protocol aims to design a universal international standard for the radio air interface and its software, so that communications and computers can be further combined, allowing portable devices produced by different manufacturers to have the ability to communicate with each other in a short range without cables. Once the plan was announced, it was widely supported and adopted by nearly 2,000 manufacturers, including Motorola, Lucent, Compaq, Siemens, 3Com, TDK and Microsoft.

Bluetooth technology also works in the 2.4GHz ISM band, using fast frequency hopping and short packet technology to reduce co-frequency interference, ensuring the reliability and security of physical layer transmission, with certain networking capabilities, and supporting 64Kbps real-time voice. Bluetooth technology is becoming increasingly popular, and related products on the market are also increasing. However, with the emergence of ultra-wideband technology, wireless LAN and zigbee technology, especially its security, price, power consumption and other issues are becoming increasingly apparent, and its competitive advantage has begun to decline. In 2004, the Bluetooth Working Group launched version 2.0, which tripled the bandwidth and reduced power consumption by half, which to a certain extent rebuilt the confidence of the industry.

Since Bluetooth technology and Zigbee technology have certain commonalities, they are often used in wireless sensor networks.

2. Other Wireless Personal Area Network Standards

Wireless sensor networks need to build a complete network from the physical layer to the application layer, and the wireless personal area network standard has formulated physical layer and media access control layer specifications for it in advance. In addition to the IEEE 802.15.4 and Bluetooth technologies discussed above, wireless personal area network technology solutions also include: ultra-wideband (UWB) technology, infrared (IrDA) technology, home radio frequency (HomeRF) technology, etc. Their common characteristics are short distance, low power consumption, low cost, and personal use. They are all used in the underlying protocol solutions of wireless sensor networks in different application scenarios. A brief introduction is as follows:

(1) Ultra-wideband (UWB) technology

Ultra Wide-Band (UWB) technology originated in the late 1950s. It is a technology that uses broadband radio wave signals ranging from a few Hz to a few GHz. By emitting extremely short pulses and receiving and analyzing the reflected signals, information about the detected object can be obtained. Because UWB uses an extremely high bandwidth, its power spectrum density is very flat, which means that the output power at any frequency point is very small, even lower than the noise emitted by ordinary equipment, so it has good anti-interference and security. Ultra Wide-Band technology was originally used mainly as a military technology in application fields such as radar detection and positioning. The US FCC (Federal Communications Commission) allowed the technology to enter the civilian field in February 2002. In addition to low power consumption, the transmission rate of ultra-wideband technology can easily reach more than 100Mbps, and its second-generation products are expected to reach more than 500Mbps. This indicator alone makes many other technologies far behind. The standard dispute surrounding UWB has been very fierce from the beginning. Freescale's DS-UWB and MBOA advocated by TI have gradually emerged. In recent years, domestic research in this area has also been very popular.

Due to its low power consumption, high bandwidth and strong anti-interference ability, ultra-wideband technology undoubtedly has a fantastic development prospect, but ultra-wideband chip products have not yet been launched, which undoubtedly leaves us with a big regret. In recent years, reports on related products have begun to appear, but this technology with profound background still needs the joint promotion of the entire industry. At present, ultra-wideband technology can be said to be showing its edge. I believe it is a late bloomer and will surely play a big role in wireless sensor network applications.

(2) Infrared (IrDA) technology

Infrared technology is a technology that uses infrared rays for point-to-point communication. It is promoted by the Infrared Data Association (IrDA), a non-profit organization founded in 1993. The association is committed to establishing world standards for wireless communication connections and currently has more than 130 formal corporate members. The transmission rate of infrared technology has increased from the original FIR 4Mbps to the current VFIR 16Mbps, and the receiving angle has also expanded from the original 30° to 120°. Since it is only used for point-to-point communication and has a certain directionality, data transmission is less subject to interference. Due to its advantages such as small product size, low cost, low power consumption, and no need for frequency application, infrared technology has been widely used since its birth, and can be said to be an evergreen tree in the field of wireless personal area networks. After years of development, its hardware and supporting software technologies have become quite mature. At present, there are at least 50 million devices in the world using IrDA technology, and it is still growing at an annual rate of 50%. Today, 95% of laptops are equipped with IrDA interfaces, and remote control devices (TVs, air conditioners, digital products, etc.) are more commonly using infrared technology.

However, IrDA is a line-of-sight transmission technology, and its core component, the infrared LED, is not very durable, let alone a stable network that can run for a long time. As a result, infrared technology has never become a standard physical layer technology for wireless personal area networks. It has only been attempted in a very small number of wireless sensor network applications (such as positioning tracking), and was used in conjunction with other wireless technologies.

(3) HomeRF technology

The Home Radio Frequency Working Group (HomeRF WG) was established in March 1998 and is led by the US Home Radio Frequency Committee. The first members include Intel, IBM, Compaq, 3Com, Philips, Microsoft, Motorola and other companies. Its main purpose is to build an interoperable voice and data network in the home under the premise that consumers can afford it. The Home Radio Frequency Working Group formulated the Shared Wireless Access Protocol (SWAP) in 1998, which is mainly aimed at home wireless LANs. The data communication of this protocol adopts the simplified IEEE 802.11 protocol standard and uses the Ethernet Carrier Sense Multiple Access/Collision Detection (CSMA/CD) technology; its voice communication adopts the DECT (Digital Enhanced Cordless Telephony) standard and uses the Time Division Multiple Access (TDMA) technology. The operating frequency band of home radio frequency is 2.4GHz, which initially supported data and audio data at a transmission rate of 2Mbps. The new home radio frequency 2.x standard uses WBFH (Wide Band Frequency Hopping) technology, adds frequency hopping modulation function, and the data bandwidth peak can reach 10Mbps, which can meet most applications.

Around 2000, the penetration rate of home radio frequency technology once reached 45%. However, since the technical standards were controlled by dozens of companies and were not as open as infrared technology, especially with the emergence of the 802.11b standard, the penetration rate of home radio frequency suddenly dropped to 30% starting in 2001. In 2003, the Home Radio Frequency Working Group announced the suspension of research and development and promotion. The once glorious home radio frequency finally withdrew from the historical stage of wireless personal area networks, like a flash in the pan.

3. Routing and high-level standards

Based on the underlying standards discussed above, some high-level protocol standards including routing and application layers have emerged, including zigbee/IEEE 802.15.4, 6LowPAN, IEEE1451.5 (wireless sensor communication interface standard), etc. In addition, Z-Wave Alliance, Cypress (Wireless USB Sensor Network), etc. have also launched similar standards. However, before the standards designed specifically for wireless sensor networks come out, zigbee is undoubtedly the most popular and is also highly praised by many application manufacturers. Here is a brief introduction.

(1) Zigbee protocol specifications

The Zigbee Alliance was founded in August 2001. Its initial members included Honeywell, Invensys, Mitsubishi, Motorola and Philips. It currently has more than 200 members. The Zigbee 1.0 (Revision 7) specification was officially launched in December 2004. In December 2006, Zigbee 2006 (Revision 13), version 1.1, was launched. In 2007, Zigbee 2007 Pro was launched. In the spring of 2008, there were some updates. Zigbee technology has many advantages such as low power consumption, low cost, large network capacity, short latency, security and reliability, and flexible operating frequency bands. It is currently a widely favored wireless personal area network solution and is also regarded by many as the de facto standard for wireless sensor networks.

The Zigbee Alliance has standardized the network layer protocols and application programming interfaces (APIs). The Zigbee protocol stack architecture is based on the seven-layer model of the open system interconnection model, including the IEEE 802.15.4 standard and the network layer and application layer protocols independently defined by the alliance. The network layer developed by Zigbee is mainly responsible for the construction and maintenance of network topology, as well as device addressing and routing, which belongs to the general network layer function category. The application layer includes the application support sub-layer (APS), the Zigbee Device Object (ZDO) and the application components customized by the equipment manufacturer, which are responsible for the convergence of business data flows, device discovery, service discovery, security and authentication, etc.

In addition, the Zigbee Alliance is also responsible for the interoperability testing and certification specifications of Zigbee products. The Zigbee Alliance regularly holds ZigFest events to give manufacturers who develop Zigbee products an opportunity to communicate openly and complete the interoperability testing of their devices. In terms of certification, the Zigbee Alliance has defined three levels of certification: Level 1 is to certify the physical layer and media access control layer, which has the most direct relationship with chip manufacturers; Level 2 is to certify the Zigbee protocol stack, also known as the Zigbee Compliant Platform Certification; Level 3 is to certify Zigbee products. Only products that pass the Level 3 certification are allowed to be labeled with the Zigbee logo, so it is also called the Zigbee Logo Certification.

Protocol chips are the carriers of protocol standards and are also the easiest form of intellectual property. Currently, there are many zigbee chip products and solutions on the market, including: Jennic's JN5121/JN5139, Chipcon's CC2430/CC2431 (acquired by TI) and Freescale MC13192, Ember's EM250 zigbee and other series of development tools and chips. Table 1 compares the indicators of these chips.

(2) IEEE 1451.5

In addition to the above two general specifications, in different application fields of wireless sensor networks, dedicated standards for specific industries are also being developed, such as electric power and water power, industrial control, consumer electronics, smart home, etc. Here, we will briefly discuss IEEE1451.X using the industrial control field as an example. Of course, industrial standards are complex and diverse. Recently, ISA SP100, a wireless technology standard specifically for industrial automation applications, is being formulated. Many Chinese industrial and academic colleagues have worked hard to participate in the formulation of this standard.

The IEEE1451 family of standards defines a set of universal communication interfaces to enable industrial transmitters (sensors + actuators) to be independent of the communication network and connected to existing microprocessor systems, instrumentation and fieldbus networks, solving compatibility issues between different networks and ultimately achieving interchangeability and interoperability between transmitters and networks. The IEEE1451 family of standards defines the hardware and software interfaces of transmitters and divides sensors into two-layer module structures. The first layer is used to run network protocols and application hardware, called the Network Capable Application Processor (NCAP); the second layer is the Smart Transducer Interface Module (STIM), which includes transmitters and electronic data sheets TEDS. The IEEE1451 working group has successively proposed five standard proposals (IEEE1451.1-IEEE1451.5), which are aimed at different industrial application site requirements, among which IEEE1451.5 is a wireless sensor communication interface standard.

The IEEE1451.5 standard proposal was first launched in June 2001. It proposed an open standard wireless sensor interface under the existing IEEE1451 framework to meet the needs of different application fields such as industrial automation. IEEE1451.5 uses wireless transmission media as much as possible, describes the wireless connection specifications between smart sensors and network adapter modules, rather than the wireless connection between network adapter modules and the network, and realizes the interoperability between IEEE 802.11, Bluetooth, and Zigbee wireless interfaces of network adapter modules and smart sensors. The focus of the IEEE1451.5 proposal is to formulate the communication data model and communication control model in the process of wireless data communication. The IEEE1451.5 proposal standard must have a general extension of the data model to allow a variety of wireless communication technologies to be used, mainly including two aspects: one is to define a general quality of service (QOS) mechanism for transmitter communication, which can map services to any radio technology, and each wireless radio technology has a mapping layer to map specific configuration parameters of wireless transmission to the quality of service mechanism. The specific content of the standard will not be discussed in detail here.

(3) 6LowPan Draft

Wireless sensor networks have been associated with the next generation of the Internet since their birth. 6LowPan (IPv6 over Low Power Wireless Personal Area Network) is a draft standard that combines these two fields. The goal of this draft is to develop how to transmit IPv6 messages on LowPAN (low power personal area network). The open protocol currently used by LowPAN mainly refers to the IEEE802.15.4 media access control layer standard mentioned above. There is no real open standard in the upper layer to support routing and other functions. Since IPv6 is the next generation Internet standard and is technically mature, and the use of IPv6 protocol on LowPan can achieve seamless connection with IPv6 network, the Internet Engineering Task Force (IETF) has set up a special working group to develop relevant technical standards such as how to send and receive IPv6 messages on the 802.15.4 protocol.

The reason why IPv6 packets are transmitted over 802.15.4 is that the existing mature IPv6 technology can well meet some requirements of the LowPan interconnection layer. First, many devices in the LowPan network require stateless automatic configuration technology. The IPv6 Neighbor Discovery protocol provides two automatic configuration technologies based on the diversity of hosts: stateful automatic configuration and stateless automatic configuration. In addition, there may be a large number of devices in the LowPan network, which requires a large IP address space. This problem is not a problem for the IPv6 protocol with a 128-bit IP address; secondly, when the packet length is limited, the IPv6 address can be selected to include the 802.15.4 media access control layer address.

The original design of IPv6 and 802.15.4 protocols was to be applied to two completely different networks, which led to many problems in directly transmitting IPv6 packets on 802.15.4. First, the packet lengths of the two protocols are incompatible. The maximum packet length allowed by IPv6 packets is 1280 bytes, while the maximum packet length of the media access control layer of 802.15.4 is 127 bytes. Since the address domain information itself (even some bytes need to be reserved for security settings) occupies 25 bytes, the upper layer load domain is at most 102 bytes, which obviously cannot directly carry data packets from the IPv6 network; secondly, the address mechanisms used by the two are different. IPv6 uses a hierarchical cluster address, which is composed of multiple segments of address segment prefixes with specific meanings and host numbers; while in 802.15.4, a 64-bit or 16-bit flat address is directly used; in addition, the protocol design requirements of the two devices are different, and energy saving is not considered when designing the IPv6 protocol. In 802.15.4, many devices are battery-powered and have limited energy, so it is necessary to minimize data communication volume and communication distance to extend the network life; finally, the two network protocols have different optimization goals. In IPv6, the general concern is how to quickly forward packets, while in 802.15.4, how to achieve reliable communication while saving device energy is its core goal.

In short, due to the different design starting points of the two protocols, there are still many technical problems that need to be solved for IEEE802.15.4 to support the transmission of IPv6 data packets, such as message fragmentation and reassembly, header compression, address configuration, mapping and management, mesh routing forwarding, neighbor discovery, etc., which will not be discussed one by one here.

4. Domestic standardization and internationalization

In recent years, the standardization work in the field of wireless sensor networks in China has made great progress under the promotion of the National Information Technology Standardization Technical Committee (hereinafter referred to as the Standardization Committee). After more than a year of preparation, the Standardization Committee organized domestic and overseas Chinese experts to hold the first "Wireless Personal Area Network Technical Standard Seminar" at the China Electronics Technology Standardization Institute on November 29, 2005, to discuss the progress of wireless personal area network standards, market analysis and standard formulation. The meeting suggested that wireless sensor networks be included in the scope of wireless personal area networks, and a special interest group was established (there are also interest groups such as low-speed wireless personal area networks and ultra-wideband). Since then, China's wireless sensor network standardization work has taken the first step.

After nearly two years of joint efforts by more than 30 domestic scientific research and industrial entities, the working group has organized eight national technical seminars and proposed the 780MHz (779-787 MHz) dedicated frequency band and related technical standards for low-speed wireless personal area networks, which have been officially approved by the National Radio Management Committee (Japan uses 950MHz and the United States uses 915MHz). For this frequency band, the working group proposed the MPSK modulation and coding technology with independent intellectual property rights, breaking away from the patent constraints of similar foreign technologies. From March 3 to 4, 2008, the working group voted on the opinion letter "Specific requirements for local and metropolitan area networks for telecommunications and information exchange between information technology systems Part 15.4: Physical layer and media access control layer specifications for low-rate wireless personal area networks (WPAN)" and passed the proposal to use MPSK and O-QPSK modulation and coding technology in the 780MHZ working frequency band as the co-alternative physical layer technical specifications for low-rate wireless personal area networks (MPSK and O-QPSK were proposed by relevant groups in China and the United States respectively, and each has intellectual property rights), that is, LR-WPAN can use either MPSK and OQPSK, or use them together, and will eventually form the IEEE 802.15.4c standard. In addition, the IEEE 802.15.4e, which includes the MAC/PHY two-layer protocol and was drafted by Chinese and Chinese experts, is also progressing smoothly (industrial wireless standards support ISA SP-100.11a is added to IEEE 802.15.4-2006 media access control, and is compatible with IEEE 802.15.4c). This is an important progress in domestic standardization work and an important step for my country to participate in the formulation of international standards. The Institute of Computing Technology is one of the formal members of this working group and has participated in some of its work.

Recently, the standardization of wireless sensor networks in China and internationally has made new progress. First, the National Standardization Administration has officially approved the separation of wireless sensor networks from the wireless personal area network working group and established a wireless sensor network standard working group directly under the National Information Technology Standardization Administration (the secretariat is now affiliated with the Institute of Microsystem, and the Institute of Computing Technology, as one of its member units, will be committed to the formulation of the standard). The working group is expected to complete its preparatory work around April 10, 2008, which marks a major step forward in the standardization of sensor networks; secondly, the International Organization for Standardization has also established the ISO/IEC JTC1/SGSN research group to start the formulation of international standards related to sensor networks. China, the United States, South Korea, Japan and other countries are participating in it as important member units. Its first meeting will also be held in Shanghai, China at the end of June 2008. The meeting will not only have domestic and foreign experts in related fields to discuss some key issues in the technical field, but also many companies engaged in sensor network applications will bring their best products to the exhibition. At the same time, the member countries will conduct in-depth discussions on the sensor network standard framework to lay the foundation for the detailed design of the draft standard.

Standards are the link between scientific research and industry, and chips are the most direct form of implementation of standards. Participating in standardization work, especially participating in the formulation of international standards, plays a vital role in improving the competitiveness and technical level of our products and occupying the commanding heights of the industry. The ultimate goal of formulating standards is to provide convenience for improving the level of the industry, meeting the internationalization of products, protecting independent intellectual property rights, and being compatible with similar or supporting products. If we can participate in the formulation of domestic and international standards related to wireless sensor networks, we will obtain strong guarantees in chip design, solution provision and product manufacturing in this field. System chips, as the most direct manifestation of standards, will be the key components of wireless sensor network application systems. They are not only the main determinant of cost, but also the main manifestation of intellectual property rights. Standards without industry seem pale and powerless, just a piece of paper; standards without chips seem to be nominal and just talk on paper. However, the current level of chip design and industrialization (especially RF chips) in China is low and the ability is relatively weak. These are two key links that urgently need to make breakthroughs in the field of wireless sensor networks. Standard formulation and communication chips are two indispensable aspects in the current sensor network field.