Power-Saving And Lifetime-Aware Data Gathering Algorithms For Wireless Sensor Networks

Wireless sensor networks produced in the1970s, gradually booming from the initial direction of the military to civilian applications. After entering the21st century, with advances in technology, particularly the development of computer communication technology, sensor technology, and VLSI, the cost of production of sensor is getting lower, the size is getting smaller, the range of applications is getting wider, this further promote the development of sensor network. The main function of the wireless sensor network is to collect the data of interested regions by the sensor nodes and transmit to the data to the viewers.In wireless sensor networks, the resources of sensors of sensor nodes is extremely limited, e.g., the processing capability of the node is weak, the storage of memory is short, the distance of radio transmission is short. The battery energy is low, etc. Thus, in wireless sensor networks, to achieve reliable transmission of data packets is a very important research topic.This paper focuses on researching the reliability of data transmission of wireless sensor network. Firstly, it introduced the basic situation of the development of wireless sensor; and pointed out the characteristics, application fields and facing challenges, etc of wireless sensor network. Secondly, it introduced the common methods of reliable transmission of data, such as multi-path transmission mechanism and ARQ mechanism, etc; and pointed out the advantages and disadvantages of traditional methods. By reviewing large amounts of literatures and latest research achievements, this paper applied network coding technology into reliable data transmission of wireless sensor network. The research work on data transmission reliability is mainly embodied in the following aspects:First, Considering multi-path data transmission reliability of single source node and single sink node basing on network coding, and only the situation of source node coding and no coding in mid-side node. For improving the efficiency of coding and decoding, it proposed to construct one Vandermonde vector as coding vector of source node, analyzed to generate n new data packages from source node via network coding to K data packages. By constructing multiple disjointed reliable paths to conduct transmission on n data packages, as long as guaranteeing that aggregation node can successfully receive at least k data packages, then decoding can be successful and k original data packages can be acquired. However, as due to the difference of hop counts of multiple transmission paths, and the difference of probability of data package loss among data transmission link, it results in that the time of successfully transmitting one data package is different. Then data package transmission volume of each path can be calculated basing on transmission time of each path. By conducting simulation experiment, and comparing with traditional multi-path transmission mode, multi-path data transmission under network coding can better upgrade the reliability of data transmission. Under different coding coefficient, i.e. under the situation of big coefficient and more data redundancy, the improvement on the reliability of data transmission shall be very remarkable.Second, Considering the reliability of data transmission among source node and multiple sink nodes. As multiple pairs may exist some interleaving nodes in the process of data transmission, interleaving nodes shall simultaneously receive data package transmitted from multiple links; retransmission progresses one by one as per order, while node content is very limited, once node buffer cache is full in storage, data overflow shall occur, then new data package can not be received and shall be lost, decreasing data transmission reliability. For resolving such a problem, the key is to conduct network coding on interleaving nodes to improve the throughput of data transmission, and prevent data package loss due to data overflow. Therefore, it pointed out to use routing path finding of EERQ to find interleaving nodes that conform to coding conditions, and analyzed the probability of data overflow. By conducting simulation experiment, within the scope of transmitting certain amount of data package, coded interleaving nodes have obvious role in decreasing data overflow; but if the frequency of transmitting data package is too fast, and data volume too large, then the effect of decreasing data overflow would not be obvious.The research results of this paper shall have certain application value in improving the reliability of data package transmission in wireless sensor network.