Extrinsic LLR of Soft-Demapper under Presence of Channel Estimation Errors
Extrinsic LLR of Soft-Demapper under Presence of Channel Estimation Errors
复制标题
存在信道估计误差时软解映射器的外在 LLR
DOI：
10.1109/vtcfall.2013.6692205
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
and S. Sampei
中科院分区：
文献类型：
--
作者：
H. Sasaki;S. Ibi;and S. Sampei
本文提出了一种新的软解映射器的外赋对数似然比（LLR），在存在信道估计误差的情况下将其传递到最大后验概率（MAP）解码器。原则上，为了降低MAP解码器中的计算复杂度，外部LLR应该服从高斯分布。然而，信道估计误差恶化了由传统定义导出的LLR的高斯性。为了保证信道估计的高斯性，本文根据信道估计的均方误差定义了可选的外对数似然比。建议LLR的推导扩展到迭代信道估计的情况下。我们将证明，建议的外部LLR是能够提高误码率（BER）的性能。
This paper proposes a novel extrinsic log likelihood ratio (LLR) of soft demapper to be conveyed to maximum a-posteriori probability (MAP) decoder under the presence of channel estimation errors. In principle, the extrinsic LLR should obey Gaussian distribution for the sake of reducing computational complexity in the MAP decoder. However, channel estimation errors deteriorate Gaussianity of the LLR derived by conventional definition. In order to guarantee the Gaussianity, this paper defines alternative extrinsic LLR according to mean square error (MSE) of channel estimates. The derivation of proposed LLR is extended to an iterative channel estimation scenario. We will demonstrate that the proposed extrinsic LLR is capable of improving bit error rate (BER) performances.