Predictable 802.11 packet delivery from wireless channel measurements
Predictable 802.11 packet delivery from wireless channel measurements
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DOI：
10.1145/1851182.1851203
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发表时间：
2010-08
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通讯作者：
D. Halperin;Wenjun Hu;Anmol Sheth;D. Wetherall
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作者：
D. Halperin;Wenjun Hu;Anmol Sheth;D. Wetherall
众所周知，RSSI是出于多种原因是否可以工作的幻想指标。这极大地使操作变得复杂，因为它需要测试和适应性才能找到最佳的速率，传输功率或其他调谐以提高性能的参数。我们表明，第一次可以从仅提供的通道测量值中准确预测商品802.11 NIC的无线数据包。我们的模型使用802.11N通道状态信息测量作为我们使用有效SNR概念开发的OFDM接收器模型的输入。它很简单，易于部署，广泛有用且准确。它可以对802.11a/g SISO速率和802.11N MIMO率的数据包提供预测，以及发射功率和天线的选择。我们报告了显示狭窄的过渡区域（大多数链接的<2 dB）的测试式实验，类似于狭窄的频率，频率通道的近乎理想的情况。与RSSI不同，这使我们能够预测可用于链接，修剪传输功率等的最高利率。我们使用痕量驱动的模拟表明，即使在动态通道上，我们的速率预测与802.11a/g的最佳速率适应算法一样好，并将此良好的性能扩展到802.11N。
RSSI is known to be a fickle indicator of whether a wireless link will work, for many reasons. This greatly complicates operation because it requires testing and adaptation to find the best rate, transmit power or other parameter that is tuned to boost performance. We show that, for the first time, wireless packet delivery can be accurately predicted for commodity 802.11 NICs from only the channel measurements that they provide. Our model uses 802.11n Channel State Information measurements as input to an OFDM receiver model we develop by using the concept of effective SNR. It is simple, easy to deploy, broadly useful, and accurate. It makes packet delivery predictions for 802.11a/g SISO rates and 802.11n MIMO rates, plus choices of transmit power and antennas. We report testbed experiments that show narrow transition regions (<2 dB for most links) similar to the near-ideal case of narrowband, frequency-flat channels. Unlike RSSI, this lets us predict the highest rate that will work for a link, trim transmit power, and more. We use trace-driven simulation to show that our rate prediction is as good as the best rate adaptation algorithms for 802.11a/g, even over dynamic channels, and extends this good performance to 802.11n.