The Research On The Environmental Monitoring Network Based On WSN And GSM

Wireless Sensor Network (WSN, abstraction for"wireless sensor network"or"sensor network"used in this paper) is composed of masses of cheap sensor nodes distributing in monitoring area, and is a Multi-Hop Networks that is self-organizing, task-oriented and data-centered through Wireless Communication Technology. It differs from the traditional Wireless Communication Technology, and possesses the characteristics of centering on data, huge network size, ever-changing topological structure and self-organizing, so that it is beneficial for obtaining vast random researching data in a large scope.This project collects light intensity of the area being monitored by using WSN, takes the advantage of public communication network's vast coverage area, low maintaining cost to realize long-distance monitoring. Meanwhile, basing on numerous researches on WSN routing protocol and aiming at the shortcomings in the common routing protocol, this project proposes an innovative routing protocol. This protocol gives much concern on energy efficiency and link quality, and it also takes routing protocol's security into consideration .It has strong augment ability.I. Hardware DesignWSN includes sensor node, sink node, and management node. Sensor node is the principal part of the whole network, locates in the monitored area, and has the functions of data collection and routing; Sink node is a special gateway with a wireless communication interface, to achieve the protocol conversion between WSN and public communication networks, data fusion, data transmission, distribute management and configuration information issues by management nodes; management node is usually the micro-computer, to storage, analyze the monitoring data of WSN, and to manage and configurate. Therefore, the focus of this project is sensor node and sink node.i. Hardware Design on Sensor NodeThe major characteristic of sensor node is limitation of energy. As a result the first consideration should be energy saving.The design adopts low power CC2420 chip which meets the standard of 2.4GHz IEEE802.15.4 as core of wireless transceiver module, and ultra-low power MSP430F149 chip as the processor, S1087 as light intensity collector, in order to collect, save and send the light intensity in the monitoring area.ii. Hardware Design on Sink NodeSink node has sufficient energy, so the design focuses on the needs of network management and data transmission. On the bases of assuring functions, it considers power control.The design takes the low power LPC2292 as its processor, SST39VF160 as its external memory, and guarantees the credible data transmission. Its connection part with WSN adopts CC2420 as the core of wireless transceiver module; the connection part with public communication network adopts GSM MODEM. Meanwhile, there is a 128×64 Lattice LCD to monitor and debug data.The overall hardware design takes the system's augmentability and flexibility into consideration, and adopts the method of module design; and it provides an unite integrated interface for wireless sink node, in order to extend in the future.II. Software Designi. Software Design on Sensor NodeSince the processing capacity and storage capacity of wireless sensor node is limited, this project adopts sensor network oriented TinyOS as its operating system.TinyOS is written by nesC language. Considering of the characteristics of sensor network, it introduces the technology of light thread, active message, event-driven and component programming.At the sensor node, data collection, communication between nodes, construction and maintenance of routing are achieved. In communication, this design adopts data frame format that is completely consonant with IEEE802.15.4 protocol.ii. Software Design on Sink NodeSince the sink node's tasks are excessive, TinyOS's Multi-task Scheduling is not as perfect asμC/OS-II, as a result, sink node always adoptsμC/OS-II as its operating system.μC/OS-II is a multi-task real time operating system, and is composed by C language and assemble language. Its structure is clear.In this design, it put transplantation ofμC/OS-II on the sink node that is based on LPC2292. At sink node, construction and maintenance of routing table are achieved. It receives and processes data from managing node and sensor node, the function of data materials backuping and time synchronization is also realized.In the software design, the data saving mode is carefully defined, and the problem of short longevity of chip because of frequent scrapes is solved.III. Design on routing protocolRoute discovery and maintenance is a core technology of WSN. Its main task is creating route between sensor node and sink node to pass the data reliably.This paper proposes a completely new Alterable Tree-based Routing Protocol (ATRP).ATRP routing protocol is a hierarchical, based on tree structure, alterable node grade, safe and reliable, low powered,dynamic adaptive routing protocol.At the ATRP routing protocol, using tree structure network topological structure, every sensor node only maintains the routing information of its father node and child node, and sink node maintains the global routing information.When the network structure changes, node grade changes automatically according to rule, so the network has high flexibility. When the nodes increase, mobile or fail, it realizes only by changing partial routing information. Node balances the network energy and avoids hot point and hot post because of numerous data, and it advances network's whole life cycle effectively through the electronic charge monitoring of itself and adjusting of realization grade.Through the rule of link's two-way verification, only sending data to father node and father node not searching child node actively, it advances the network's reliability and effectively avoids, delays partial attack to WSN. Through test and comparison with common WSN protocol, ATRP protocol can balance energy, reliability, augmentability. It is better than common routing protocol especially on safety, and is a perfect WSN routing protocol.IV. ConclusionThis design completely realizes the environmental monitoring network based on WSN and GSM through collection, routing and forwarding to light Intensity of monitoring area.The whole project designs and realizes completely. It solves the WSN's design, also the software and hardware problem in practice fundamentally. It proposes an excellent routing algorithm creatively, and gives unique, effective whole solutions for application in WSN used in environmental monitoring even other aspects.