Using proximity and quantized RSS for sensor localization in wireless networks
Using proximity and quantized RSS for sensor localization in wireless networks
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DOI：
10.1145/941350.941354
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发表时间：
2003-09
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通讯作者：
Neal Patwari;A. Hero
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作者：
Neal Patwari;A. Hero
对于无线传感器网络，已提出接收信号强度（RSS）和接近度（也称为连接性）测量作为估计设备与传感器位置之间的距离的简单且廉价的手段。虽然RSS测量被认为由于衰落信道的随机特性而遭受误差，但是邻近测量，即，仅知道两个设备是否在通信范围内，经常被讨论而不考虑它们受到相同衰落信道的影响。接近度测量实际上只是RSS测量的二进制量化。我们使用的Cramér-Rao界（CRB）的无偏传感器位置估计的情况下，RSS和邻近测量的最小可达到的方差进行比较。为了完整性，我们还提出了CRB传感器定位系统使用K级量化RSS（QRSS）测量，其中邻近测量的特殊情况：K=2。例子是一个未知位置的传感器的情况下，和传感器的5 × 5网格的情况下。这些例子表明，作为经验法则，基于邻近度的系统中的标准差的下限比基于RSS的系统的界限高约50%。此外，结果显示多少比特的量化是必要的QRSS为基础的系统，几乎实现了一个未量化的RSS系统的界限。
For wireless sensor networks, received signal strength (RSS) and proximity (also known as connectivity) measurements have been proposed as simple and inexpensive means to estimate range between devices and sensor location. While RSS measurements are recognized to suffer from errors due to the random nature of the fading channel, proximity measurements, ie., knowing only whether or not two devices are in communication range, are often discussed without considering that they are affected by the same fading channel. Proximity measurements are actually just a binary quantization of RSS measurements. We use the Cramér-Rao bound (CRB) to compare the minimal attainable variances of unbiased sensor location estimators for the cases of RSS and proximity measurements. For completeness, we also present the CRB for sensor localization with systems using K-level quantized RSS (QRSS) measurements, of which proximity measurements are the special case: K=2. Examples are presented for the case of one unknown-location sensor, and for the case of a 5 by 5 grid of sensors. These examples show that lower bounds for standard deviation in proximity-based systems are, as a rule of thumb, about 50% higher than the bounds for RSS-based systems. Furthermore, results are presented which show how many bits of quantization are necessary for a QRSS-based system to nearly achieve the bounds of an unquantized RSS system.