公开(公告)号：US09432224B1

公开(公告)日：2016-08-30

申请号：US14841438

申请日：2015-08-31

Applicant: Huawei Technologies Co., Ltd.

Inventor： Jeebak Mitra ,  Zhuhong Zhang

IPC: H04L25/03 ,  H04L1/20 ,  H04B1/00 ,  H04L27/26

CPC classification number: H04L25/03292 ,  H04B1/00 ,  H04L1/20 ,  H04L5/0048 ,  H04L25/0212 ,  H04L25/0226 ,  H04L25/023 ,  H04L25/0236 ,  H04L25/03114 ,  H04L25/03178 ,  H04L27/2613 ,  H04L27/2647 ,  H04L27/2675 ,  H04L2025/03547

Abstract: It is possible to perform ISI estimation for quasi-static band-limited communication channels using a minimal number of discontinuous pilots communicated across different time intervals. In one example, at least two frames are received in different time intervals, and noise vectors are extracted from pilots carried in the respective frames. Spectral estimation is performed on the noise vectors, collectively, to obtain a set of tap coefficients, which are then used to perform ISI equalization on at least one of the frames. In this way, ISI equalization is performed on a frame communicated in one time interval using at least some pilots communicated in another time interval. Using discontinuous pilots to perform channel estimation may enable lower pilot densities in next-generation communication systems.

Abstract translation: 可以使用在不同时间间隔内传送的最小数量的不连续导频来执行准静态带限通信信道的ISI估计。 在一个示例中，以不同的时间间隔接收至少两个帧，并且从各个帧中携带的导频中提取噪声向量。 共同地对噪声矢量进行频谱估计，以获得一组抽头系数，然后这些抽头系数用于在至少一个帧上执行ISI均衡。 以这种方式，使用在另一个时间间隔中传送的至少一些导频，在一个时间间隔中传送的帧上执行ISI均衡。 使用不连续导频来执行信道估计可以使下一代通信系统中的导频密度降低。

公开(公告)号：US09385896B1

公开(公告)日：2016-07-05

申请号：US14795636

申请日：2015-07-09

Applicant: Huawei Technologies Co., Ltd.

Inventor： Jeebak Mitra ,  Zhuhong Zhang

IPC: H04L27/02 ,  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：US10903912B2

公开(公告)日：2021-01-26

申请号：US16872967

申请日：2020-05-12

Applicant: HUAWEI TECHNOLOGIES CO., LTD.

Inventor： Rene Janicek ,  Jeebak Mitra

IPC: H04B10/06 ,  H04B10/61 ,  H04B10/079 ,  H04B10/69

Abstract: The disclosed structures and methods are directed to a method for compensation of linear and nonlinear effects in optical fiber of a coherent optical signal transmitted through an optical link. The method comprises receiving a coherent optical signal having carriers; determining values of intensity vectors for each carrier; determining values of filtered intensity vectors for each carrier by filtering the values of the intensity vectors at frequencies lower than a cut-off frequency of a filter; determining nonlinear compensation coefficients for each carrier based on the filtered intensity vectors; and modifying the digital coherent optical signal based on the nonlinear compensation coefficients.

公开(公告)号：US20190199443A1

公开(公告)日：2019-06-27

申请号：US16293324

申请日：2019-03-05

Applicant: Huawei Technologies Co., Ltd.

Inventor： Mahdi Zamani ,  Jeebak Mitra ,  Hossein Najafi ,  Zhuhong Zhang ,  Chuandong Li

IPC: H04B10/61

CPC classification number: H04B10/616 ,  H04B10/548 ,  H04B10/5561 ,  H04B10/613 ,  H04B10/614

Abstract: Aspects of the present disclosure are directed in part to a receiver DSP unit including an equalization module. The equalization module includes a trellis-based equalization module that may utilize multiple trellis-based processors (TBP), which can each be individually adaptively configured for performing a trellis-based equalization. The design of the TBPs allows them to be configured for compensating a residual Inter-Symbol Interference (ISI) as well as compensating a residual Phase Noise (PN). ISI is an example of an additive impairment and PN is an example of a multiplicative impairment that communication systems, particularly high speed transmission systems such as coherent optical systems, can suffer from.

公开(公告)号：US09998274B2

公开(公告)日：2018-06-12

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: H04B10/00 ,  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：US20170099165A1

公开(公告)日：2017-04-06

申请号：US14876378

申请日：2015-10-06

Applicant: HUAWEI TECHNOLOGIES CO., LTD.

Inventor： Jeebak Mitra ,  Zhuhong Zhang

IPC: 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：US20230031180A1

公开(公告)日：2023-02-02

申请号：US17375831

申请日：2021-07-14

Applicant: Huawei Technologies Co., Ltd.

Inventor： Jeebak Mitra ,  Mrinmoy Jana ,  Lutz Hans-Joachim Lampe ,  Jin Wang ,  Chuandong Li

IPC: H04B10/2543 ,  H04J14/02 ,  H04B10/58

Abstract: Methods and systems for low complexity interference cancellation in multichannel optical transmission. Local or self-iteration is performed one or more times between an expected propagation decision feedback equalizer and a soft demapper. Following local iteration, a soft decision forward error correction decoder determines bit log-likelihood ratios, which are fed back to the expected propagation decision feedback equalizer and soft demapper for further self-iteration. Global iteration involving the decoder can also be performed one or more times before a bitstream is decoded.

公开(公告)号：US10680718B2

公开(公告)日：2020-06-09

申请号：US16293324

申请日：2019-03-05

Applicant: Huawei Technologies Co., Ltd.

Inventor： Mahdi Zamani ,  Jeebak Mitra ,  Hossein Najafi ,  Zhuhong Zhang ,  Chuandong Li

IPC: H04B10/548 ,  H04B10/61 ,  H04B10/556

Abstract: Aspects of the present disclosure are directed in part to a receiver DSP unit including an equalization module. The equalization module includes a trellis-based equalization module that may utilize multiple trellis-based processors (TBP), which can each be individually adaptively configured for performing a trellis-based equalization. The design of the TBPs allows them to be configured for compensating a residual Inter-Symbol Interference (ISI) as well as compensating a residual Phase Noise (PN). ISI is an example of an additive impairment and PN is an example of a multiplicative impairment that communication systems, particularly high speed transmission systems such as coherent optical systems, can suffer from.

公开(公告)号：US09774400B2

公开(公告)日：2017-09-26

申请号：US15184815

申请日：2016-06-16

Applicant: Huawei Technologies Co., Ltd.

Inventor： Jeebak Mitra ,  Zhuhong Zhang

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

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.

公开(公告)号：US11558115B1

公开(公告)日：2023-01-17

申请号：US17375831

申请日：2021-07-14

Applicant: Huawei Technologies Co., Ltd.

Inventor： Jeebak Mitra ,  Mrinmoy Jana ,  Lutz Hans-Joachim Lampe ,  Jin Wang ,  Chuandong Li

IPC: H04B10/2543 ,  H04B10/58 ,  H04J14/02

Abstract: Methods and systems for low complexity interference cancellation in multichannel optical transmission. Local or self-iteration is performed one or more times between an expected propagation decision feedback equalizer and a soft demapper. Following local iteration, a soft decision forward error correction decoder determines bit log-likelihood ratios, which are fed back to the expected propagation decision feedback equalizer and soft demapper for further self-iteration. Global iteration involving the decoder can also be performed one or more times before a bitstream is decoded.