Research Of 6LoWPAN Technology And Implementation Of Hearder Compression

Wireless network is a burgeoning network, whose development speed is so rapid that its speed exceeded most people's expectations. The wireless network has had many branches, and the most important of branches is the internet of things. The internet of things can connect all objects through the internet, so that objects can communicate with each other via the internet and people can check the status of the object and communicate with the object through the internet of things. The technology has been applied to various fields, such as power grid, building, road, oil and gas pipelines and so on. Today people's life already could not leave the internet of things and has already closely linked with the development of the internet of things.The wireless embedded internet is a subset of the internet of the internet of things. It includes resource-limited embedded devices, often battery powered, connected by low-power, low-bandwidth wireless networks to the internet. IEEE 802.15.4 was released as the first global low-power radio standard in 2003, which is mainly used in low-power wireless personal area network. ZigBee is an IEEE 802.15.4-based wireless ad hop control network, but due to its capabilities scalability, evolvability and internet integration are limited and it is mainly used in the wireless embedded networks within the region, so it is not suitable for the wireless embedded internet.6LoWPAN (IPv6 over Low-Power Wireless Personal Area Network) is an IPv6 over low-power wireless personal area network, whose appearance makes it possible for the wireless embedded internet.6LoWPAN is actually an adaptation layer, also called LoWPAN adaptation layer, and its underlying protocol is IEEE 802.15.4, the upper layer protocol is IPv6.It implements the link function between IEEE 802.15.4 and IPv6, which is an important innovation of 6LoWPAN.Because the quantity of the wireless embedded network nodes is very huge, and the nodes are ip-enabled, so it requires a lot of IP addresses. The amount of IPv4 addresses is limited, and it is recently announced the depletion of IPv4 addresses, while the amount of IPv6 addresses is very large. And there are many advantages of IPv6 which IPv4 doesn't have, such as stateless address auto-configuration and network routing, and the security of IPv6 is better than the security of IPv4.Therefore, it is very advisable for the nodes of the wireless embedded internet to use IPv6 addresses.There are more emphasizes on the research of 6LoWPAN Technology abroad. IETF established 6LoWPAN Working Group in 2004, the working group's main job is to make and improve the 6LoWPAN standards and extend the functionality of 6LoWPAN.It is widely applied abroad, f or example, health care, industrial control and automotive control. The research for 6LoWPAN is very limited in our country. Some colleges and institutes participate in the research of 6LoWPAN and only a few enterprises participate in the development and the application of the technology which is related to 6LoWPAN.In fact, the potential of the development of 6LoWPAN is huge,but people know it very limited because it is regarded as a new technology. When deeply known about 6LoWPAN, people will believe its prospect of application is very broad.This paper gives a detailed description of 6LoWPAN.It also analyses and designs the core technology of 6LoWPAN. Meanwhile, it summarizes the work of the next. The main contents are as follows.Introduction of the relevant technical background:This introduces two main technical standards, which are IEEE 802.15.4 standard and IPv6 standard. The contents and protocol format of the two main technical are introduced in detail, and this paper describes the architecture and the standards of protocol of each 6LoWPAN network layer. Detailed analyses and design of the adaptation layer:6LoWPAN adaptation layer is the most important layer of 6LoWPAN protocol stack. The related technologies of 6LoWPAN are implemented in the adaptation layer, such as fragmentation, reassembly, header compression, forwarding and routing. First the role of adaptation layer and frame format are introduced here, and then 6LoWPAN neighbor discovery technology is described in detail, so we can know the differences between 6LoWPAN neighbor discovery technology and IPv6 neighbor discovery technology.Analyses, design and implementation of header compression:Although the adaptation layer can fragment and reassemble lager packets, but this can't solve problems of data transfer rate and efficiency. The maximum transmission unit of IEEE 802.15.4 is 127 bytes, but the header of the packet would use most of it. So it is very essential to user header compression. There are two methods of header compression which are stateless header compression and context-based header compression and are introduced in detail in this paper. With the compare between them, it is known that the efficiency of context-based header compression is better, so the implementation of context-based header compression is described in detail.Test and summary:This section is divided into hardware design, software design and simulation system test. In the design of node's hardware, we select CC2420 as the radio frequency chip. Atmega128L as the main controller and they transfer data through SPI bus. In the design of software, it is to ensure the success of initialization and the success of sending and receiving data normally. The simulation software is COOJA. which is a LINUX-based simulation system. Through the simulation of wireless network by using COOJA, it can be learnt that include power consumption, duty cycle and packet loss of the nodes and so on. After system testing, the entire system is running normally and it realizes the design goals of 6LoWPAN. The implementation and test of 6LoWPAN provide a more comprehensive reference and the foundation of theory and practice of the application of 6LoWPAN in our country.