对于能量受限制的无线网络,节点的交替休眠是有效的节能方式,但是会造成网络连通性破坏,使网络成为部分连接网络.部分连接可用性的定量研究,对采用休眠模式的网络具有重要意义.文中提出了一种基于交替活跃模型的部分连接可用性的计算模型,利用泊松过程分析和全概率建模法得到了可用性的计算公式,有效地衡量了采用休眠模式的部分连接网络的通信能力;同完全连接可用性进行了定量对比,证明了在允许的端到端延迟范围内,部分连接可用性明显高于完全连接可用性,为节能的部分连接网络的部署提供了理论依据;分析了网络参数同包递交率、延迟等指标的关系,并给出满足条件约束的配置方法;通过仿真验证了分析结果的有效性.
In energy-constrained wireless networks, alternately sleeping is an effective way to reduce power consumption. However,this method may destroy the connectivity of network. Such a network is called the partially connected network. The numerical evaluation for the availability of partial connection is essential for wireless network running in periodically sleeping mode. In this paper, a computing model of partial connection availability based on alternate activity model is introduced. A node with packet to be send can hold the packet for certain period and resume packet forwarding when the sleeping next-hop node wakes up. Based on the Poisson process model and complete probability method, the formula of the partial connection availability is deduced. The formula can be very close to the actual capacity of the partially connected network in alternately sleeping mode. It is proved that compared with the full connection availability, within tolerable delay the partial connection availability is much higher. The theoretical criterion is provided in the process of deployment of energy-constrained wireless networks. Numerical analysis is conducted on the relationship among relevant network parameters and performance of networks such as packet delivery ratio and delay. Methods for setting the parameters are introduced. Simulation validates the methods and results.