公开(公告)号：US20180091288A1

公开(公告)日：2018-03-29

申请号：US15353394

申请日：2016-11-16

Applicant: Huawei Technologies Co., Ltd.

Inventor： Mahdi Zamani ,  Mehdi Torbatian ,  Jeebak Mitra ,  Zhuhong Zhang ,  Chuandong Li

IPC: H04L7/00 ,  H04B10/60

CPC classification number: H04L7/0075 ,  H04B10/60

Abstract: An optical channel between a coherent optical transmitter and a coherent optical receiver may include one or more components that act as a bandpass filter with a passband that is narrower than the signal bandwidth. Such a narrow filter may significantly attenuate the signal content close to the band edge of the data signal. As a result, timing error detection may work less effectively, and therefore clock recovery may be less effective or fail. Methods and systems are disclosed in which a single optical carrier is used to transmit a data signal that has multiple bands, and timing error detection is performed at the receiver using one or more inner bands of the multiple bands. The timing error detection may therefore be made more robust to the effects of the narrow filtering.

公开(公告)号：US09660845B2

公开(公告)日：2017-05-23

申请号：US14876378

申请日：2015-10-06

Applicant: Huawei Technologies Co., Ltd.

Inventor： Jeebak Mitra ,  Zhuhong Zhang

IPC: H01L23/02 ,  H04L25/03

CPC classification number: H04L25/03203 ,  H04L2025/0342

Abstract: Embodiment reduced-state trellis equalization techniques compute accumulated path metrics (APMs) for a subset of candidate states for at least some stages in the trellis based on a neighborhood map of an ML state. This reduces the number of APMs that are computed and stored during trellis equalization. Other embodiments select a subset of candidate states for which APMs are transported to the next stage of the trellis based on the neighborhood map. This eliminates the need to sort the remaining APMs during reduced state trellis equalization. The neighborhood map identifies a subset of the highest probability neighbors for an ML state. The subset of candidate states identified as highest probability neighbors may be saved in a look-up table. The look-up table may be generated offline and/or generated/updated dynamically during run-time operation.

公开(公告)号：US20170012712A1

公开(公告)日：2017-01-12

申请号：US15184815

申请日：2016-06-16

Applicant: Huawei Technologies Co., Ltd.

Inventor： Jeebak Mitra ,  Zhuhong Zhang

IPC: H04B10/61 ,  H04B10/2513 ,  H04L25/03

CPC classification number: H04B10/6161 ,  H04B10/25133 ,  H04L25/03197 ,  H04L25/03203 ,  H04L25/03216 ,  H04L25/067

Abstract: Quasi-reduced state trellis equalization techniques achieve low-latency inter-symbol interference (ISI) equalization by selecting a subset of accumulated path metrics (APMs) for a leading symbol to propagate over a trellis to candidate states of a trailing symbol. This simplifies the computation of APMs for candidate states of the trailing symbol. Thereafter, APMs for candidate states of the trailing symbol are computed based on the subset of APMs for the leading symbol that were propagated over the trellis. Propagating fewer than all APMs for the leading symbol to the trailing symbol reduces the complexity of APM computation at the trailing symbol.

Abstract translation: 准减速状态网格均衡技术通过选择用于先行符号的累积路径度量（APM）的子集来实现低等待时间间符号间干扰（ISI）均衡，从而将网格传播到尾随符号的候选状态。 这简化了尾随符号的候选状态的APM的计算。 此后，基于在网格上传播的领先符号的APM的子集来计算用于候选状态的尾随符号的APM。 传播较少的所有APM的领先符号到尾随符号减少APM计算在尾随符号的复杂性。

公开(公告)号：US09503305B1

公开(公告)日：2016-11-22

申请号：US14849281

申请日：2015-09-09

Applicant: Huawei Technologies Co., Ltd.

Inventor： Jeebak Mitra ,  Zhuhong Zhang

IPC: H04B1/66 ,  H03K9/00 ,  H04L27/00 ,  H04L27/06 ,  H04L27/36 ,  H04L1/00

CPC classification number: H04L27/36 ,  H04L1/0047

Abstract: It is possible to compress log likelihood ratios (LLRs) by exploiting the mapping symmetry between bits in the same symbol. For example, two LLRs corresponding to the same dimension of a square Quadrature Amplitude Modulation (QAM) symbol can be compressed into a single compressed LLR that excludes the magnitude bits of one of the LLRs because the magnitude component of LLRs for bits corresponding to the same dimension of a square QAM symbol exhibit a piecewise linear relationship with one another. Similar techniques can be used to exploit piecewise linear relationships between a subset of constellation points in a non-square QAM constellation.

Abstract translation: 可以通过利用相同符号中的位之间的映射对称来压缩对数似然比（LLR）。 例如，对应于正方形正交幅度调制（QAM）符号的相同维度的两个LLR可以被压缩为排除一个LLR的幅度比特的单个压缩LLR，因为对应于同一个比特的比特的LLR的幅度分量 平方QAM符号的尺寸彼此呈现分段线性关系。 可以使用类似的技术来利用非正方形QAM星座中星座点的子集之间的分段线性关系。