Analysis And Implementation Of MAC And Network Layers Of ZigBee Protocol Based On Real-Time Operating System

In recent years, ZigBee is developed as a low power consumption, low-cost WSN communication protocol, which is suitable for the fields of smart home, intelligent agriculture, industrial data collecting and etc. As the rapid development of these WSN applications, the requirements to communication protocols in terms of stability, throughput, real-time when transmitting are becoming more stringent. Among of these, the real-time response time directly affects the highest transmit frequency that the ZigBee communication protocol can reach to, which also in turn determines the communication performances of WSN and restricts the applications of ZigBee in some high real-time required areas. Currently, the Z-Stack, which is a main ZigBee protocol stack developed by TI Corporation, is realized based on a non-real-time operating system named OSAL. While in domestic ZigBee areas, most of corporations just simply make use of TI's protocol stack without improving the operating system. Thus, it is quite important to introduce the real-time operating system into ZigBee in order to efficiently manage stack and enhance its real-time property. Besides, the standards of low power consumption and working stability should be guaranteed as well. This thesis started from the real-time system, systematically described the implementation of MAC layer and network layer in ZigBee protocol stack which is based on FreeRTOS, and in turn analysed the performances.The main work arranged as follows:Ⅰ. The construction of hardware plant.MSP430F5438 microcontroller is used as the core processor module and CC2420 chip is selected as the RF transceiver to construct a stable plant for ZigBee protocol stack.Ⅱ. Real-time operating system.FreeRTOS, which is a totally open sourced and free real-time operating system, is utilized as original working basis. This thesis introduces the improved operating system into ZigBee protocol stack to build a stronger foundation in terms of real-time and low power consumption.Ⅲ. The implementation of the MAC layer of ZigBee protocol.Cygwin and IAR Embedded Workbench are used to complete the MAC layer with C language.Ⅳ.The implementation of the network layer of ZigBee protocol.Above mentioned tools are also used to conduct code implementation of Network layer.Ⅴ. Experiments and evaluations.Testings and contrastive analysis are carried out to evaluate the reliability, throughput, real-time property and power consumption of ZigBee protocol.At the last part of the thesis, the main contents are summarized and suggestions of the future research work in this field are given.