| In wireless sensor networks, the sink node is the only interface between thesensor network and the external network. It transmits the monitoring data of thesensor network to the external network, and releases users’ monitoring task to sensornodes. In this thesis, we emphasize the work on the point-to-multipointcommunications between the sink node and sensor nodes as well as the WAN accessof the sink node, and design a wireless sensor network with CC1101and GPRS.In terms of the point-to-multipoint communications, the star topology and theTime Division Multiple Address (TDMA) mechanism are adopted to realize themultipoint communications of this network. As precise time synchronization of nodesis needed in TDMA mechanism, the Flooding Time Synchronization Protocol (FTSP)is adopted in the first time slot of TDMA frame to get the sink node and sensor nodessynchronized, thus to guarantee the operation of TDMA mechanism. In addition, tomeet the demand of low-power consumption of the wireless sensor network, the RFtransceiver chip CC1101manufactured by TI is chosen for the data transmission.In terms of the WAN access, GPRS network is adopted, which has theadvantages of low cost, wide coverage, always online and so on. The sink node getsaccess to the Internet through GPRS network with the GTM900-C module, andtransmits the monitoring data to the monitoring center in real time. Two softwareswith client/server mode are programmed and operated on the upper computer of thesink node and the server of the monitoring center respectively. Then, several functionsare realized, including the instant message transmission, file transmission with anyformat and real-time transmission of monitoring data.A long time test is carried out in the real environment to assess the performanceof this network, in terms of the precision of synchronization, the connection of GPRSnetwork and the transmission of data respectively. Test results show that this networkcan achieve reliable time synchronization and data transmission. |
PDF Full Text Request