Research On Communication Protocol And Dedicated Test Platform In Wireless Sensor Networks

Wireless sensor networks (WSN) have become a research hotspot for future-oriented information technology. Communication protocol is a key technology for wireless sensor networks. According to the characteristics of WSN, this paper presents a dedicated communication protocol stack and makes simulations by OMNeT++, then designs and implements a dedicated test platform based on TinyOS and CC2530.Firstly, this paper gives an overview of wireless sensor network technology and discusses the common physical layer, MAC layer and network layer protocols. The physical layer consists mainly 802.11, bluetooth, infrared and 802.15.4 protocol. The MAC layer consists mainly competition-based, scheduling-based and hybrid MAC protocol. The network layer includes planar routing protocol and hierarchical routing protocol.Then, this paper proposes a dedicated hierarchical framework for communication protocol stack of wireless sensor networks, and presents the optimization method of physical layer, MAC layer and network layer protocol. The optimization and improvement of physical layer protocol mainly includes the core parameters selection of frequency band and spreading parameters. The optimization and improvement of MAC layer protocol mainly includes:priority mechanism is introduced in the frame structure, the priority of decision feedback ACK is added. The optimization and improvement of network layer protocol mainly includes:the network mechanism for nodes is improved, adaptive load balancing strategy is added. By OMNeT++, this paper builds the simulation model based on IEEE 802.15.4 standard, then simulates the meanE2EDelay and meanLossRate in different paramater settings, and analyses the effort of key parameters on the protocol performance.And then, this paper presents the design of the dedicated test platform for wireless sensor networks. The architecture of the test platform consists of three layers:hardware platform, protocol stack and testing program. Hardware platform is achieved based on TI’s CC2530 Development Kit, mainly includes a central node, three sensor nodes and a test PC. The protocol stack is realized based on ZigBee/802.15.4 protool stack on TinyOS. The test program is written based on nesC programming language. One of the key work of this paper is the transplantation of TinyOS on the CC2530 platform.Finally, this paper makes verified implemention and test of the MAC protocol based on the dedicated test platform. This paper describes the implementation of competition-based and scheduling-based MAC protocol. The two types of protocols are tested by printing of serial port and wireless data capture software. According to the test results, transmission delay, the probability of collision and other indicators of the two types of MAC protocols are compared. The conclusion is:the competition-based MAC protocol is suitable when traffic load is not heavy and small transmission delay is required; the scheduling-based MAC protocol is suitable when transmission data cannot be lost and data transmission can have a certain time delay.