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arXiv 1301.6956cs.ITmath.IT
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无线信道容量的物理方法

The Capacity of Wireless Channels: A Physical Approach

Wonseok Jeon, Sae-Young Chung

摘要:

在本文中,无线信道的容量的特点是基于电磁和天线理论,只有最小的假设。我们假设发射机可以在一个球形区域内产生任意的电流分布,并且接收天线均匀分布在发射机周围的一个更大的球体上。在大量接收天线的限制下,容量被示出为$(αP/N_0) \log e$ [比特/秒],其中$P$是发射功率约束,$α$是接收天线的归一化密度,并且$N_0$是噪声功率谱密度。虽然这个结果看起来微不足道,但它在两个方面令人惊讶。首先,这个结果与带宽无关(带宽甚至可以小到可以忽略不计)。其次,该结果表明,容量与包含发射机的区域的大小无关。这是对以前的一些结果,声称的最大自由度是成比例的表面积包含发射器归一化的波长的平方。我们的结果具有重要的实际意义,因为它表明,即使是一个紧凑的天线阵列,可以忽略不计的带宽和天线间距远低于波长可以提供一个巨大的吞吐量,如果阵列是足够大,使天线间距的波长的顺序。

英文摘要:

In this paper, the capacity of wireless channels is characterized based on electromagnetic and antenna theories with only minimal assumptions. We assume the transmitter can generate an arbitrary current distribution inside a spherical region and the receive antennas are uniformly distributed on a bigger sphere surrounding the transmitter. The capacity is shown to be $(αP/N_0) \log e$ [bits/sec] in the limit of large number of receive antennas, where $P$ is the transmit power constraint, $α$ is the normalized density of the receive antennas and $N_0$ is the noise power spectral density. Although this result may look trivial, it is surprising in two ways. First, this result holds regardless of the bandwidth (bandwidth can even be negligibly small). Second, this result shows that the capacity is irrespective of the size of the region containing the transmitter. This is against some previous results that claimed the maximum degrees of freedom is proportional to the surface area containing the transmitter normalized by the square of the wavelength. Our result has important practical implications since it shows that even a compact antenna array with negligible bandwidth and antenna spacing well below the wavelength can provide a huge throughput as if the array was big enough so that the antenna spacing is on the order of the wavelength.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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