| 摘要: |
| 提出了覆盖质量随时间变化的反应覆盖策略.反应覆盖的主要思想是:当目标流没有到达任务区域时,网络的覆盖强度最低,但是能够检测目标流的到达,以节省能量;当目标流到达时,节点被唤醒,网络为目标流提供高质量的感知覆盖;当目标流离开网络时,节点又进入低能耗的监视状态.因此,反应覆盖比静态覆盖更加能量高效,比事件驱动覆盖的感知延迟要小,从而更适合对目标流的感知覆盖.分析和讨论了反应覆盖策略的基本问题,给出了感知占空比、唤醒邻居数、持续工作时间等理论结果,最后通过仿真实验评估了反应覆盖的初始检测延迟、覆盖质量、网络生存期.仿真实验数据显示,反应覆盖的初始检测延迟对目标流的覆盖质量影响较小,当目标流较大(目标数大于30)时,覆盖质量接近静态覆盖质量,而网络生存期增加了4～7倍. |
| 关键词: 反应覆盖 静态覆盖 目标流 到达间隔时间 Poisson分布 |
| DOI： |
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| 基金项目:Supported by the National Natural Science Foundation of China under Grant Nos.60603061, 60603064 (国家自然科学基金) |
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| Proactive Coverage Method for Monitoring Target Flow in Wireless Sensor Networks |
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WEN Jun,DOU Qiang,JIANG Jie,QI Xing-Yun,DOU Wen-Hua
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| Abstract: |
| This paper presents a time-variant coverage mechanism, proactive coverage. In proactive coverage, all sensor nodes work in lower power surveillance manner which can detect target intrusion with high probability to save energy when the target flow doesn’t arrive. As soon as the target flow arrives, sensor nodes are awakened to build a local high quality coverage networks to sense intervening targets. When target flow leaves the target field, sensor nodes converge to a quiet surveillance state. Proactive coverage is more energy efficient than static area coverage, higher sensing quality than event-driven coverage. This paper analyzes preliminary problems in proactive coverage and finds theoretic results on initial detecting delay, awaking nodes strategy and active sensing duration. Numeric results from simulation reveal that initial detecting delay in proactive coverage is trivial. Compared with static area coverage, this coverage mechanism for an adequate scale target flow (above 30 targets) can prolong the network’s lifetime to near 4～7 times. |
| Key words: proactive coverage static coverage target flow arrive interval Poisson distribution |
