ExOR: Opportunistic multi-hop routing for wireless networks
ExOR: Opportunistic multi-hop routing for wireless networks
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DOI：
10.1145/1090191.1080108
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发表时间：
2005-10-01
影响因子：
2.8
通讯作者：
Morris, R
中科院分区：
文献类型：
--
作者：
Biswas, S;Morris, R
本文介绍了 ExOR，这是一种集成路由和 MAC 协议，可提高多跳无线网络中大型单播传输的吞吐量。 ExOR 在传输该跳之后选择数据包路由的每一跳，以便该选择可以反映哪些中间节点实际接收到传输。这种推迟的选择为每次传输提供了多次取得进展的机会。因此，ExOR 可以使用具有高丢失率的长无线电链路，而传统路由可以避免这种情况。 ExOR 提高了连接的吞吐量，同时不使用比传统路由更多的网络容量。ExOR 的设计面临以下挑战。接收每个数据包的节点必须就其身份达成一致并选择一个转发器。一致协议必须具有较低的开销，但也必须足够健壮，以至于它很少转发数据包零次或多次。最后，ExOR 必须选择到达最终目的地的剩余成本最低的转发器。在 38 节点 802.11b 测试台上进行的实施测量表明，与传统路由相比，ExOR 提高了大多数节点对的吞吐量。对于传统路由使用一跳或两跳的线对，ExOR 强大的确认可防止不必要的重传，从而将吞吐量提高近 35%。对于距离较远的对，ExOR 利用转发器的选择来提供 2 到 4 倍的吞吐量增益。
This paper describes ExOR, an integrated routing and MAC protocol that increases the throughput of large unicast transfers in multi-hop wireless networks. ExOR chooses each hop of a packet's route after the transmission for that hop, so that the choice can reflect which intermediate nodes actually received the transmission. This deferred choice gives each transmission multiple opportunities to make progress. As a result ExOR can use long radio links with high loss rates, which would be avoided by traditional routing. ExOR increases a connection's throughput while using no more network capacity than traditional routing.ExOR's design faces the following challenges. The nodes that receive each packet must agree on their identities and choose one forwarder. The agreement protocol must have low overhead, but must also be robust enough that it rarely forwards a packet zero times or more than once. Finally, ExOR must choose the forwarder with the lowest remaining cost to the ultimate destination.Measurements of an implementation on a 38-node 802.11b test-bed show that ExOR increases throughput for most node pairs when compared with traditional routing. For pairs between which traditional routing uses one or two hops, ExOR's robust acknowledgments prevent unnecessary retransmissions, increasing throughput by nearly 35%. For more distant pairs, ExOR takes advantage of the choice of forwarders to provide throughput gains of a factor of two to four.