传感网中延迟限定的非汇聚数据移动式收集

在大规模的无线传感器网络中收集数据,不仅需要考虑节点的能量消耗,而且还需要考虑数据收集延迟.如何有效地均衡节点的能量消耗,同时最小化数据收集延迟,是一个具有挑战性的问题.为了均衡节点的能量消耗,利用移动数据收集器收集数据.以此为基础,提出一种DC-Collection算法来解决数据收集延迟和能耗的问题.首先,在网络中构造最短路径树,网络非连通时,不同的网络子图可以构造多棵最短路径树,它们构成一个最短路径树集合;其次,在每一棵最短路径树上选取部分节点作为采集节点和逗留节点,使得以采集节点为根的限高树的高度不超过h,且在每个采集节点的通信区域内至少有一个逗留节点;再次,在每棵限高树内调整树的结构,让能量高的节点承担更多的子孙节点,最大化限高树的生命周期;最后,移动数据收集器从Sink出发,遍历逗留节点所在位置收集数据,最终回到起点,并将数据发送给Sink.通过理论分析和大量仿真实验,其结果表明:与现有的数据收集协议相比,DC-Collection不仅能够均衡各节点的能量消耗从而延长网络生命周期,而且能够缩短移动数据收集器收集数据行走的路径长度,从而缩短数据收集延迟.

Delay-Constrained Data Collection Without Aggregation in Wireless Sensor Network With Mobile Collector

For data gathering in large-scale wireless sensor networks, not only energy consumption of nodes but also data collection delay should be considered. It is a challenging problem to achieve the goal of balancing energy consumption of nodes and minimizing data collection delay in the network at the same time. In order to balance energy consumption of nodes, this paper utilizes a mobile data collector to collect data in the network, and proposes an algorithm named DC-Collection to solve the problem of minimizing data collection delay and energy consumption. First, DC-Collection constructs a shortest path tree. If the network is not connected, there are more than one shortest path trees (i.e., there is a set of shortest path trees in the network). Second, some nodes in the trees are selected as collective nodes or lingering nodes, where a collective node is the root of a height-limited tree that will receive data sent from its descendant nodes and a lingering node is a normal node that the mobile data collector will visit at a given time to collect sensing data. The mobile data collector can collect the data of all nodes in the network as long as it traverses the locations of all lingering nodes. The heights of the trees that rooted at the collective nodes are limited to be smaller than h. There is at least a lingering node exists in the communication area of each collective node. Third, DC-Collection adjusts the structures of the height-limited trees. It makes nodes with higher energy level possess more descendants, so as to maximize the network lifetime by balancing the energy consumption of nodes. Finally, the mobile data collector starts from a Sink, and traverses locations of the lingering nodes in sequence to collect data. After collecting all the data, it returns to the starting point and uploads the data to the Sink. Compared with existing algorithms, theoretical analyses and simulations show that DC-Collection can not only balance the energy consumption of nodes to prolong the network lifetime, but also shorten the path length that the mobile data collector walks to reduce the data collection delay.