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arXiv cs/0610025cs.ITmath.IT
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QAM星座上的低相关序列

Low Correlation Sequences over the QAM Constellation

M. Anand, P. Vijay Kumar

摘要:

本文首先介绍了在大小为M^2=4^m的QAM星座上的低相关序列族及其作为CDMA设置中的扩频序列的潜在适用性。五个结构,它示出了如何这样的序列家庭有能力传输更大量的数据,以及使可变速率的反向链路上的信令。规范族CQ具有周期N,归一化最大相关参数theta_max由A sqrt(N)限制,其中“A”的范围从16-QAM情况下的1.8到大M的3.0。在CDMA设置中,每个用户能够在扩频序列的每个周期传送2 m比特的数据,通过将序列族的大小减半,该扩频序列可以增加到3 m比特的数据。用于构建CQ的技术很容易扩展到产生更大的序列家族,并提供了一个例子。所选系列SQ具有较低的theta_max值,但仅允许(m+1)比特数据调制。交织的16-QAM序列族IQ具有theta_max <= sqrt(2)sqrt(N)并且支持3比特数据调制。剩余的两个族在M^2-QAM星座的大小为2 M的正交PAM(Q-PAM)子集上。与系列SQ相比,系列P具有较低的theta_max值,同时仍然允许(m+1)比特数据调制。在8进制Q-PAM星座上的交织族IP允许3比特数据调制,并且有趣的是,实现了theta_max的Welch下界。

英文摘要:

This paper presents the first concerted look at low correlation sequence families over QAM constellations of size M^2=4^m and their potential applicability as spreading sequences in a CDMA setting. Five constructions are presented, and it is shown how such sequence families have the ability to transport a larger amount of data as well as enable variable-rate signalling on the reverse link. Canonical family CQ has period N, normalized maximum-correlation parameter theta_max bounded above by A sqrt(N), where 'A' ranges from 1.8 in the 16-QAM case to 3.0 for large M. In a CDMA setting, each user is enabled to transfer 2m bits of data per period of the spreading sequence which can be increased to 3m bits of data by halving the size of the sequence family. The technique used to construct CQ is easily extended to produce larger sequence families and an example is provided. Selected family SQ has a lower value of theta_max but permits only (m+1)-bit data modulation. The interleaved 16-QAM sequence family IQ has theta_max <= sqrt(2) sqrt(N) and supports 3-bit data modulation. The remaining two families are over a quadrature-PAM (Q-PAM) subset of size 2M of the M^2-QAM constellation. Family P has a lower value of theta_max in comparison with Family SQ, while still permitting (m+1)-bit data modulation. Interleaved family IP, over the 8-ary Q-PAM constellation, permits 3-bit data modulation and interestingly, achieves the Welch lower bound on theta_max.

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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