Multiple-accessing over frequency-selective fading channels
Multiple-accessing over frequency-selective fading channels
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DOI：
10.1109/pimrc.1995.477378
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发表时间：
1995-09
期刊：
影响因子：
--
通讯作者：
R. Knopp;P. Humblet
中科院分区：
文献类型：
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作者：
R. Knopp;P. Humblet
这项工作考虑了在受到多径传播损害的信道上，从许多独立信源到公共接收器的信息传输。在蜂窝无线电通信中，上行链路就是这种情况。我们从检查多用户频率选择性衰落信道的可达速率区域开始，而不知道传输端上的信道。理论上，扩频多址(SSMA)比频分多址(FDMA)或慢跳频具有更高的数据速率[L]。当所有用户的平均接收功率相等时，我们证明了SSMA的最大频谱效率比FDMA或许多用户的慢跳频高5772 NAT/S/Hz，并具有瑞利衰落。在发射机已知所有信道的情况下，给出了最优的多址接入方案。结果是，只有一个用户应该以任何给定的频率进行传输。此外，发射机的输入功率谱在频率和时间上都是充满水的公式。结果表明，最优方案的频谱效率明显高于SSMA和FDMA方案。
This work considers the transmission of information from many independent sources to a common receiver over a channel impaired by multipath propagation. In cellular radio communications this is the case of the uplink. We start by examining the achievable rate region of the multiuser frequency-selective fading channel without knowledge of the channel on the transmission end. It has been shown that SSMA (Spread Spectrum Multiple Access) is theoretically capable of higher data rates than FDMA (Frequency Division MuZfiple Access) or slow frequency-hopping[l]. When the average received power for all the users is equal, which corresponds to a perfect slow power control, we show that the maximum spectral efficiency of SSMA exceeds that of FDMA or slow frequency-hopping by 5772 nats/s/Hz for many users and Rayleigh fading. Also, we formulate the optimal multiple-access scheme when all the channels are known to the transmitters. In turns out that only one user should transmit at any given frequency. Morecver, the input power spectra for the transmitters are water-filling formulae both in frequency and time. It is shown that the spectral efficiency for the optimal scheme is significantly higher than both those of SSMA and FDMA.