Frequency-Domain ICI Cancellation with MMSE Equalization for DS-CDMA Downlink
Frequency-Domain ICI Cancellation with MMSE Equalization for DS-CDMA Downlink
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DOI：
10.1093/ietcom/e89-b.12.3335
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发表时间：
2006-12
期刊：
影响因子：
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通讯作者：
K. Takeda;K. Ishihara;F. Adachi
中科院分区：
文献类型：
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作者：
K. Takeda;K. Ishihara;F. Adachi
基于最小均方误差（MMSE）准则的频域均衡（FDE）可以代替传统的rake组合，同时显著提高下行DS-CDMA在频率选择衰落信道中的误码率（BER）性能。然而，由于FDE后残余的片间推理（ICI）会导致扩频码之间的正交性失真，并且随着复用水平的增加，误码率性能会下降。本文提出了一种联合MMSE频域均衡（FDE）和ICI对消的方法来提高DS-CDMA下行链路的误码率性能。在该方案中，在接收信号的每个频率分量经过MMSE-FDE后，在频域产生残余ICI副本并相减。在考虑残差ICI的情况下，导出每次迭代的MMSE权重。通过计算机仿真验证了所提ICI对消方案的效果。
Frequency-domain equalization (FDE) based on the minimum mean square error (MMSE) criterion can replace the conventional rake combining while offering significantly improved bit error rate (BER) performance for the downlink DS-CDMA in a frequency-selective fading channel. However, the presence of residual inter-chip-inference (ICI) after FDE produces orthogonality distortion among the spreading codes and the BER performance degrades as the level of multiplexing increases. In this paper, we propose a joint MMSE frequency-domain equalization (FDE) and ICI cancellation to improve the BER performance of the DS-CDMA downlink. In the proposed scheme, the residual ICI replica in the frequency-domain is generated and subtracted from each frequency component of the received signal after MMSE-FDE. The MMSE weight at each iteration is derived taking into account the residual ICI. The effect of the proposed ICI cancellation scheme is confirmed by computer simulation.