Energy-efficient forwarding strategies for geographic routing in lossy wireless sensor networks
Energy-efficient forwarding strategies for geographic routing in lossy wireless sensor networks
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DOI：
10.1145/1031495.1031509
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发表时间：
2004-11
期刊：
影响因子：
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通讯作者：
K. Seada;Marco Zúñiga;A. Helmy;B. Krishnamachari
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文献类型：
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作者：
K. Seada;Marco Zúñiga;A. Helmy;B. Krishnamachari
最近的实验研究表明，真实传感器网络中的无线链路可能非常不可靠，在很大程度上偏离了常用网络仿真工具中使用的理想化的范围内接收模型。以前提出的地理路由协议通常使用最大距离贪婪转发技术，该技术在理想条件下运行良好。然而，这种转发技术在实际条件下表现不佳，因为它倾向于在有损耗的链路上转发分组。我们识别并说明了这个弱链路问题和相关的距离-跳跃权衡，即能源效率高的地理转发必须在较短、高质量的链路和较长的有损链路之间取得平衡。这项研究是在有和没有自动重发请求(ARQ)的情况下进行的。基于一个分析的链路丢失模型，我们通过数学分析和大量的黑名单/链路选择策略的模拟来研究距离-跳跃的权衡，并通过在MOTES上的一组真实的实验来验证一些策略。我们的分析、仿真和实验都表明，分组接收率(PRR)和到达目的地的距离的乘积是ARQ情况下的最优转发度量，即使没有ARQ也是一个很好的度量。使用该度量的节点通常利用过渡区域(高方差链路)中的邻居。我们的结果还表明，基于接收的转发策略比纯粹基于距离的策略更有效；相对黑名单方案比绝对黑名单方案减少了断连并获得了更高的传递率；ARQ方案在大型网络中变得更加重要。
Recent experimental studies have shown that wireless links in real sensor networks can be extremely unreliable, deviating to a large extent from the idealized perfect-reception-within-range models used in common network simulation tools. Previously proposed geographic routing protocols commonly employ a maximum-distance greedy forwarding technique that works well in ideal conditions. However, such a forwarding technique performs poorly in realistic conditions as it tends to forward packets on lossy links. We identify and illustrate this weak-link problem and the related distance-hop trade-off, whereby energy efficient geographic forwarding must strike a balance between shorter, high-quality links, and longer lossy links. The study is done for scenarios with and without automatic repeat request (ARQ). Based on an analytical link loss model, we study the distance-hop trade-off via mathematical analysis and extensive simulations of a wide array of blacklisting/link-selection strategies; we also validate some strategies using a set of real experiments on motes. Our analysis, simulations and experiments all show that the product of the packet reception rate (PRR) and the distance traversed towards destination is the optimal forwarding metric for the ARQ case, and is a good metric even without ARQ. Nodes using this metric often take advantage of neighbors in the transitional region (high-variance links). Our results also show that reception-based forwarding strategies are more efficient than purely distance-based strategies; relative blacklisting schemes reduce disconnections and achieve higher delivery rates than absolute blacklisting schemes; and that ARQ schemes become more important in larger networks.