单天线中继干扰信道的自由度研究.doc

文档介绍：
单天线中继干扰信道的自由度研究
王朝旭,张文逸**
(中国科学技术大学, 电子工程与信息科学系)
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摘要:随着移动通信的迅速发展,频谱资源匮乏问题将日益明显。另一方面,4G 通信将面
临更加恶劣和复杂的时变信道环境,再加上移动设备的功率受限等客观条件的约束,阻碍着
4G 高速率数据传输的实现。于是,在功率和频谱受限,且信道条件越发恶劣的未来移动通
信传输环境下,如何尽可能地提高频谱利用率、实现大容量传输将是 4G 研究和未来无线通
信界需要解决的最基础性的难题。本文利用干扰对齐技术对引入单天线中继的干扰信道自由
度的影响进行了分析,得到在有中继协作下,只需要较小的时延扩展可以达到很大的自由度。
因此通过一个单天线中继的协助就可以大大化简传输机和发送机的结构,同时给出了三用户
下的干扰对齐可行性预编码矩阵的构造,以及提出了一个在中继辅助下实现干扰对齐的快速
算法。
关键词:无线通信; 干扰对齐; 自由度; 信道容量; 时延扩展;
中图分类号:
The Impact on Degree of Freedom With a Single-antenna
Relay
Wang Zhaoxu, Zhang Wenyi
(Department of Electronic Engineering and Information Science, University of Science and
Technology of China, Hefei 230027)
Abstract: In this paper, we first investigate the problem of achieving the degree of freedom(DoF)
of a 3-user multiple-input-multiple output (MIMO) interference channel with a single-antenna
relay. The feasible solution of interference alignment needs infinite symbol extensions to approach
the full DoF k/2. While it was proved relays can not increase the degree of freedom of MIMO
interference channel, we find that we can exact achieve interference alignment of 3-user MIMO
interference channel with only 2 time slot extensions, using a single antenna relay. It is said that
adding a single-antenna relay can tremendous simplify the transmitter/receiver structure.
Meanwhile, detailed practical solution is given based on the idea. What’s more, we propose a
novel fast interference alignment (IA) algorithm with the help of a single-antenna relay.
Simulation results show that the proposed fast algorithm outperforms the existing traditional IA
algorithms with fast convergence.
Key words:
munication; interference alignment; Degree of Freedom (DoF);
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channel capacity; time slots extension;
0 引言
随着人们对高速率、大容量、高质量的多媒体业务的不断追求,现今的数据传输速率不
足,频谱资源匮乏等问题日益明显。通过 MIMO 技术及 OFDM 技术,虽然已经可以获得高
速率数据传播,但相应带来的更多的干扰以及更恶劣的信道环境阻碍着高速传播。现有的技
术正在一筹莫展之时,干扰对齐技术提供了一个解决方案。干扰对齐的基本思想是将期望信
号和干扰信号分别投影在接收信号的不同子空间中,使