WO2014205893A1 - 一种基于频域信道估计的接收端均衡方法和*** - Google Patents
一种基于频域信道估计的接收端均衡方法和*** Download PDFInfo
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- WO2014205893A1 WO2014205893A1 PCT/CN2013/081341 CN2013081341W WO2014205893A1 WO 2014205893 A1 WO2014205893 A1 WO 2014205893A1 CN 2013081341 W CN2013081341 W CN 2013081341W WO 2014205893 A1 WO2014205893 A1 WO 2014205893A1
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- 238000000034 method Methods 0.000 title claims abstract description 25
- 238000012549 training Methods 0.000 claims abstract description 58
- 125000004122 cyclic group Chemical group 0.000 claims abstract description 37
- 238000012546 transfer Methods 0.000 claims abstract description 22
- 239000006185 dispersion Substances 0.000 claims abstract description 14
- 238000001228 spectrum Methods 0.000 claims abstract description 12
- 238000001914 filtration Methods 0.000 claims abstract description 11
- 238000012545 processing Methods 0.000 claims description 17
- 238000011084 recovery Methods 0.000 claims description 12
- 238000004891 communication Methods 0.000 claims description 8
- 238000003780 insertion Methods 0.000 claims description 6
- 230000037431 insertion Effects 0.000 claims description 6
- 230000010287 polarization Effects 0.000 claims description 5
- 230000002269 spontaneous effect Effects 0.000 claims description 4
- 238000007781 pre-processing Methods 0.000 claims description 2
- 230000005540 biological transmission Effects 0.000 abstract description 7
- 239000013307 optical fiber Substances 0.000 abstract description 3
- 230000001131 transforming effect Effects 0.000 abstract description 3
- 238000004364 calculation method Methods 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 230000003595 spectral effect Effects 0.000 description 3
- 230000001427 coherent effect Effects 0.000 description 2
- 230000006735 deficit Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000009432 framing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/0212—Channel estimation of impulse response
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/022—Channel estimation of frequency response
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
- H04L25/03006—Arrangements for removing intersymbol interference
- H04L2025/0335—Arrangements for removing intersymbol interference characterised by the type of transmission
- H04L2025/03375—Passband transmission
- H04L2025/03414—Multicarrier
Definitions
- the present invention relates to the field of coherent optical communication transmission, and relates to a receiving end equalization method based on frequency domain channel estimation, and a system for implementing the method. Background technique
- Coherent communication based on digital signal processing technology is an important solution for long-distance optical fiber communication transmission systems. How to overcome the communication channel damage is an important issue to be solved.
- the impairment of the communication channel reduces the signal-to-noise ratio of the signal and introduces inter-symbol interference, resulting in the generation of errors.
- the equalization algorithm estimates the channel and compensates for linear distortion of the channel to attenuate or eliminate inter-symbol interference.
- TDE time domain equalization
- FDE frequency domain equalization
- Time Domain Equalization (TDE) algorithm performs channel impulse response estimation based on the training sequence or signal-based constellation characteristics, and compensates the signal in the time domain.
- the channel estimation algorithm based on the training sequence is more complicated.
- the channel estimation algorithm based on the characteristics of the signal constellation depends on the modulation format. When the modulation format changes, the algorithm also needs to change, and the algorithm effect is different. Due to the dispersion in the fiber, when the dispersion is large, the equalization algorithm requires more equalizer taps, resulting in higher algorithm complexity.
- Frequency Domain Equalization (FDE) algorithm.
- the algorithm performs estimation of the channel transfer function based on the training sequence and compensates the signal in the frequency domain.
- the channel estimation algorithm is simple, and when the dispersion is large, the algorithm complexity is still low. However, the algorithm requires a cyclic prefix/suffix to be inserted into the signal, which causes a certain signal rate overhead. Summary of the invention
- the invention provides a simple and effective receiving end equalization method based on frequency domain channel estimation, and a system for realizing the method, which can effectively perform phase noise compensation in the case where the fiber dispersion is small or the dispersion is compensated by other algorithms.
- the present invention adopts the following technical solutions:
- An equalization method based on frequency domain channel estimation includes the following steps:
- Step 1 Insert a training sequence with flat spectral characteristics into the transmitter signal
- the second step transforming the received training sequence into the frequency domain by using a fast Fourier transform (FFT) at the receiving end,
- FFT fast Fourier transform
- the ideal spectrum corresponding to the training sequence that is, the spectrum of the theoretical sequence
- IFFT inverse fast Fourier transform
- Step 3 Use the obtained time domain filter tap coefficients to filter the data signal in the time domain to achieve signal equalization.
- the training sequence is an M sequence or a chu sequence.
- the transmitting end adds a cyclic prefix/suffix to the training sequence to eliminate inter-code crosstalk; the receiving end first removes the cyclic prefix/suffix in the received training sequence, and then performs the fast Fourier Leaf transformation.
- the receiving end first performs front-end data processing on the signal received by the transmitting end, including dispersion coarse compensation, carrier frequency recovery, receive matching filtering, and digital synchronization; and performs back-end data processing after step 3), including carrier Phase recovery.
- the signal at the transmitting end is frame-transmitted, and the frame structure of each frame includes two polarization directions, each of which includes a training sequence and a data signal, and the training sequence is composed of a pair of parts, labeled as ⁇ and ⁇ 2 , alternately arranged in time, and:
- t x and ⁇ are M sequences or chu sequences, and "0" represents a sequence having a length equal to 0 in length and a chu sequence.
- the selection of the training sequence length is determined by the channel carrier frequency offset and the degree of phase drift; the selection of the number of training sequences is determined by the spontaneous radiated noise intensity in the channel; the selection of the data signal length is determined by the drift of the channel transfer function. Decide.
- An equalization system based on frequency domain channel estimation for implementing the above method, comprising a transmitting end and a receiving end,
- the transmitting end includes:
- a training sequence insertion module configured to insert a training sequence with flat spectral characteristics in a signal of the transmitting end;
- a cyclic prefix/suffix adding module configured to add a cyclic prefix/suffix to the training sequence to eliminate Crosstalk between codes;
- a transmit filtering module configured to connect the cyclic prefix/suffix join module, configured to filter a signal after adding a cyclic prefix/suffix and send the signal to a communication channel;
- the receiving end includes:
- a cyclic prefix/suffix removal module for removing a cyclic prefix/suffix in a training sequence
- An FFT module configured to connect the cyclic prefix/suffix removal module, to perform a fast Fourier transform on the training sequence with the cyclic prefix/suffix removed, and transform the frequency to the frequency domain;
- a channel transfer function estimating module connected to the FFT module, configured to divide the ideal spectrum corresponding to the training sequence to obtain a transfer function of the channel;
- An IFFT module connected to the channel transfer function estimating module, configured to perform an inverse fast Fourier transform (IFFT) to transform a signal into a time domain, to obtain a time domain filter tap coefficient;
- IFFT inverse fast Fourier transform
- An FIR filter is coupled to the IFFT module for filtering the data signal in the time domain using the obtained time domain filter tap coefficients to achieve signal equalization.
- a front-end data processing module configured to preprocess the signal received from the transmitting end, and then send the signal to the cyclic prefix/suffix removal module;
- a back-end data processing module is coupled to the FIR filter for carrier phase recovery.
- the preprocessing performed by the front end data processing module includes: dispersion coarse compensation, carrier frequency recovery, receive matching filtering, and digital synchronization.
- a decision module is further included, and the back end data processing module is connected to recover the received signal information into binary data.
- the method of the present invention combines the time-domain equalization non-insertion cyclic prefix/suffix to form a simple channel estimation of overhead and frequency domain equalization in the case where the dispersion of the optical fiber is small or the dispersion is compensated by other algorithms. This method is less complex and saves computation time.
- the equalization method of the present invention operates on a data signal equivalent to a frequency domain equalization algorithm, and thus the equalization effect is the same.
- 1 is a flow chart of a method for equalization based on frequency domain channel estimation according to an embodiment of the present invention.
- FIG. 2 is a schematic structural diagram of a signal frame according to an embodiment of the present invention.
- FIG. 3 is a schematic structural diagram of a frequency domain channel estimation based equalization system according to an embodiment of the present invention.
- FIG. 4 is a schematic diagram showing the experimental results of a 1.76 Tb/s signal 720 km transmission according to an embodiment of the present invention. detailed description
- H (k) R tr (k) tr tr where is the transmitted training sequence, (") is the received training sequence, their corresponding frequency domain form is the sum of the frequency domain equalizer tap, is the receiver estimation
- the channel transfer function, c(l) is the tap coefficient of the time domain finite impulse response (FIR) filter.
- Step 1 Insert several training sequences at the front end of the signal at the transmitting end. Take the chu sequence as an example.
- the chu sequence is:
- N is the length of the chu sequence.
- the chu sequence has the characteristics of a flat spectrum, and a sequence of M sequences having similar characteristics can also be selected in this step, and the implementation using the M sequence is the same as that using the chu sequence.
- a cyclic prefix/suffix is added to the training sequence at the transmitting end to eliminate crosstalk between codes.
- the signal is then filtered and transmitted to the receiving end.
- Step 2 At the receiving end:
- the training sequence received at the receiving end is distorted by the channel and is noisy.
- the receiving end first performs front-end data processing on it, including dispersion coarse compensation, carrier frequency recovery, receive matching filtering, digital synchronization, and the like.
- the cyclic prefix/suffix of the training sequence is removed, and the received training sequence is transformed into the frequency domain by Fast Fourier Transform (FFT), and divided by the spectrum of the ideal training sequence to obtain a channel transfer function, and the reciprocal thereof is used.
- FFT Fast Fourier Transform
- IFFT IFFT fast inverse Fourier transform
- the data signal is filtered in the time domain, that is, the data signal is linearly convolved with the filter tap, which is equalization.
- Figure 2 shows the frame structure of one frame of the signal, including two polarization directions.
- Each polarization direction includes a training sequence portion and a data signal portion.
- the training sequence consists of pairs of parts, labeled ⁇ and ⁇ 2 , alternated in time, and:
- t x and ⁇ are M sequences or chu sequences, and "0" represents a sequence having a length equal to 0 in length and a chu sequence.
- the choice of the length of the M-sequence (or chu sequence) during implementation is determined by the channel carrier frequency offset and the degree of phase drift, which is required to be short enough to ensure that the carrier frequency offset and phase are stable over a pair of training sequences.
- the choice of the number of M-sequences (or chu sequences) during the implementation is determined by the intensity of the spontaneous radiated noise in the channel, which is needed to ensure that the error caused by the spontaneous radiated noise on the channel estimation at the receiving end is small.
- the choice of the length of the data signal during implementation is determined by the degree of drift of the channel transfer function, which is required to be short enough to ensure that the transfer function of the channel does not undergo large drifts within the frame.
- FIG. 3 is a schematic diagram of the composition of an equalization system based on frequency domain channel estimation corresponding to the above method, including a transmitting end and a receiving end.
- the transmitting end includes: a training sequence insertion module, configured to insert a training sequence with flat spectral characteristics in the transmitting end signal; a cyclic prefix/suffix adding module, and the training sequence insertion module is connected, and the cyclic prefix is added to the training sequence / suffix to eliminate inter-code crosstalk; a transmit filter module, connected to the cyclic prefix / suffix join module, for filtering the signal after adding the cyclic prefix / suffix and transmitting to the receiving end;
- the receiving end includes: a front end data processing module, configured to preprocess the signal received from the transmitting end, including dispersion coarse compensation, carrier frequency recovery, receive matching filtering, digital synchronization, etc., and then sent to the cyclic prefix/suffix removal a cyclic prefix/suffix removal module for removing a cyclic prefix/suffix in the training sequence; an FFT module, connecting the cyclic prefix/suffix removal module, for performing a training sequence with a cyclic prefix/suffix removed a fast Fourier transform, which is transformed into a frequency domain; a channel transfer function estimation module, connected to the FFT module, configured to divide the ideal spectrum corresponding to the training sequence to obtain a transfer function of the channel; an IFFT module, connecting the channel transfer a function estimation module, configured to perform an inverse fast Fourier transform (IFFT) to transform a signal into a time domain, to obtain a time domain filter tap coefficient; and an FIR filter connected to the IFFT module for utilizing
- Figure 4 shows the results of the 1.76 Tb/s transmission experiment.
- the signal is the transmission distance of 720 km, and the horizontal axis is the fiber input power of the signal.
- the common algorithm of the equalization method of the present invention and the time domain equalization algorithm (the norm algorithm (CMA) plus the cascade multi-mode algorithm (CMMA))
- CMA norm algorithm
- CMMA cascade multi-mode algorithm
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Abstract
本发明涉及一种基于频域信道估计的接收端均衡方法及***,该方法首先在发射端信号中***具有平坦的频谱特性的训练序列,然后在接收端用快速傅里叶变换将接收的训练序列变换到频域,通过与对应的理想频谱相除得到信道的传递函数,然后取该传递函数的倒数并将其用快速傅里叶反变换变换到时域,得到时域滤波器抽头系数;之后利用时域滤波器抽头系数在时域对数据信号进行滤波,实现信号均衡。该***包含实现上述相应功能的各个模块。本发明结合了时域均衡的不***循环前缀/后缀造成开销和频域均衡的信道估计简单的特点,能够在光纤色散较小或色散由其他算法补偿的情形下,有效地进行相位噪声补偿,且算法复杂度小,能够节省计算时间。
Description
一种基于频域信道估计的接收端均衡方法和*** 技术领域
本发明涉及相干光通信传输领域, 涉及一种基于频域信道估计的接收端均衡方法, 以 及实现该方法的***。 背景技术
基于数字信号处理技术的相干通信是长距离光纤通信传输***的重要解决方案。 如何 克服通信信道损伤是需要解决的重要课题。 通信信道损伤使信号的信噪比降低, 并且引入 了码间干扰, 导致了误码的产生。 在光纤通信***中, 均衡算法对信道进行估计, 并补偿 信道的线性畸变, 以减弱或消除码间干扰。
目前, 均衡算法主要有两类, 一类是时域均衡 (TDE), 另一类是频域均衡 (FDE)。 两 类算法具有相同的均衡效果。
1 ) 时域均衡 (TDE) 算法。 该算法基于训练序列或基于信号的星座图特性进行信道冲 激响应估计, 在时域对信号进行补偿。 基于训练序列的信道估计算法较复杂。 基于信号星 座图特性的信道估计算法依赖于调制格式, 调制格式改变时, 算法也需要随之改变, 并且 算法效果也不同。 由于光纤中存在色散, 当色散较大时, 均衡算法需要的均衡器抽头数较 多, 导致算法复杂度较高。
2) 频域均衡 (FDE) 算法。 该算法基于训练序列进行信道传递函数的估计, 在频域对 信号进行补偿。 信道估计算法简单, 当色散较大时, 算法复杂度仍然较低。 但是该算法需 要对信号***循环前缀 /后缀, 这会造成一定的信号速率开销。 发明内容
本发明提供一种简单有效的基于频域信道估计的接收端均衡方法, 以及实现该方法的 ***, 能够在光纤色散较小或色散由其他算法补偿的情形下, 有效地进行相位噪声补偿。
为实现上述目的, 本发明采用如下技术方案:
一种基于频域信道估计的均衡方法, 包括以下步骤:
第一步: 在发射端信号中***具有平坦的频谱特性的训练序列;
第二步: 在接收端用快速傅里叶变换 (FFT)将接收的训练序列变换到频域, 通过与该
训练序列对应的理想频谱 (即理论上序列的频谱) 相除得到信道的传递函数, 然后取该传 递函数的倒数并将其用快速傅里叶反变换 (IFFT)变换到时域, 得到时域滤波器抽头系数; 第三步: 利用得到的时域滤波器抽头系数在时域对数据信号进行滤波, 实现信号均衡。 优选地, 所述训练序列为 M序列或 chu序列。
进一步地, 所述发射端在所述训练序列中加入循环前缀 /后缀以消除码间串扰; 所述接 收端先移除接收到的训练序列中的循环前缀 /后缀, 然后进行所述快速傅里叶变换。
进一步地, 所述接收端对由发射端接收的信号首先进行前端数据处理, 包括色散粗补 偿、 载波频率恢复、 接收匹配滤波和数字同步; 并在步骤 3)之后进行后端数据处理, 包括 载波相位恢复。
其中 tx和 ^为 M序列或 chu序列, "0"表示长度与 chu序列等长的数值为 0的序列。 更进一步地, 训练序列长度的选择由信道载波频率偏移和相位的飘移程度决定; 训练 序列个数的选择由信道中自发辐射噪声强度决定; 数据信号长度的选择由信道传递函数的 飘变程度决定。
一种实现上述方法的基于频域信道估计的均衡***, 包括发射端和接收端,
所述发射端包括:
训练序列***模块, 用于在发射端信号中***具有平坦的频谱特性的训练序列; 循环前缀 /后缀加入模块, 连接所述训练序列***模块, 用于在训练序列中加入循环前 缀 /后缀以消除码间串扰;
发射滤波模块, 连接所述循环前缀 /后缀加入模块, 用于对加入循环前缀 /后缀后的信号 进行滤波并发送至通信信道;
所述接收端包括:
循环前缀 /后缀移除模块, 用于移除训练序列中的循环前缀 /后缀;
FFT模块, 连接所述循环前缀 /后缀移除模块, 用于对移除循环前缀 /后缀的训练序列进 行快速傅里叶变换, 将其变换到频域;
信道传递函数估计模块, 连接所述 FFT模块, 用于除以训练序列对应的理想频谱, 得 到信道的传递函数;
IFFT模块, 连接所述信道传递函数估计模块, 用于进行快速傅里叶反变换 (IFFT) 将 信号变换到时域, 得到时域滤波器抽头系数;
FIR滤波器, 连接所述 IFFT模块, 用于利用得到的时域滤波器抽头系数在时域对数据 信号进行滤波以实现信号均衡。
进一步地, 还包括:
前端数据处理模块, 用于对从发送端接收的信号进行预处理, 然后发送至所述循环前 缀 /后缀移除模块;
后端数据处理模块, 连接所述 FIR滤波器, 用于载波相位恢复。
更进一步地, 所述前端数据处理模块进行的预处理包括: 色散粗补偿、 载波频率恢复、 接收匹配滤波、 数字同步。
进一步地, 还包括判决模块, 连接所述后端数据处理模块, 用于将接收的信号信息恢 复成二进制数据。
本发明所述方法在光纤色散较小或色散由其他算法补偿的情形下, 结合了时域均衡的 不***循环前缀 /后缀造成开销和频域均衡的信道估计简单的特点。 该方法复杂度小, 能够 节省计算时间。 在理论上本发明的均衡方法对数据信号的操作等同于频域均衡算法, 因此 均衡效果与其相同。 附图说明
图 1是本发明实施例的基于频域信道估计的均衡方法的流程图。
图 2是本发明实施例的信号帧结构示意图。
图 3是本发明实施例的基于频域信道估计的均衡***的组成结构示意图。
图 4是本发明实施例的 1.76Tb/s信号 720km传输实验结果示意图。 具体实施方式
下面通过具体实施例和附图, 对本发明做进一步详细说明。
本发明中, 发射信号与接收信号的关系如下:
C(k) = -— = 丽→ str (n) = rtr {n) * c(l)
H (k) Rtr (k) tr tr 其中, 是发射的训练序列, (《)是接收到的训练序列, 它们对应的频域形式 为 和 是频域均衡器的抽头, 是接收端估计的信道传递函数, c(l) 是时域有限冲激响应 (FIR) 滤波器的抽头系数。
下面结合本实施例的算法流程图 1对技术方案的实施进行具体说明, 图 1 中右边虚线 框所示部分为本发明方案的主要内容。
第一步: 在发射端信号前端***若干个训练序列, 以 chu序列为例, chu序列为:
同时, 由于接收端需要将训练序列变换到频域进行操作, 在发射端需要对训练序列加 入循环前缀 /后缀以消除码间串扰。 然后将信号滤波后发射至接收端。
第二步: 在接收端:
接收端接收到的训练序列受到信道的畸变, 并且带有噪声。 接收端首先对其进行前端 数据处理, 包括色散粗补偿、 载波频率恢复、 接收匹配滤波、 数字同步等。
然后, 移除训练序列的循环前缀 /后缀, 用快速傅里叶变换 (FFT) 将接收的训练序列 变换到频域, 与其理想的训练序列频谱相除, 得到信道传递函数, 取其倒数, 用 IFFT快速 傅里叶反变换 (IFFT) 变换到时域, 得到时域滤波器抽头系数: str(k)
c(l) = IDFT[C(k)] = IDFT
Rtr(k) 其中 IDFT为离散傅里叶反变换, IFFT是其一种快速实现方法。
然后, 利用得到的时域滤波器 (FIR滤波器) 抽头系数 (如图 1中 FIRtaps所示) 在时 域对数据信号进行滤波, 即将数据信号与滤波器抽头进行线性卷积, 此为均衡。
最后, 进行后端数据处理 (载波相位恢复) 和判决等。
上面方法要求信号成帧传输, 图 2显示了信号的一帧的帧结构, 包含两个偏振方向,
每个偏振方向均包含训练序列部分与数据信号部分。训练序列由成对的部分组成,标记为 ^ 和 ί2, 在时间上交替排列, 并且:
其中 tx和 ^为 M序列或 chu序列, "0"表示长度与 chu序列等长的数值为 0的序列。 实施过程中 M序列 (或 chu序列) 长度的选择由信道载波频率偏移和相位的飘移程度 决定, 需要其足够短以确保一对训练序列内载波频率偏移和相位较稳定。
实施过程中 M序列 (或 chu序列) 个数的选择由信道中自发辐射噪声强度决定, 需要 其足够多以确保自发辐射噪声对接收端信道估计造成的误差较小。
实施过程中数据信号长度的选择由信道传递函数的飘变程度决定, 需要其足够短以确 保信道的传递函数在此帧内不发生较大飘变。
图 3 为与上述方法对应的基于频域信道估计的均衡***的组成示意图, 包括发射端和 接收端。
发射端包括: 训练序列***模块, 用于在发射端信号中***具有平坦的频谱特性的训 练序列; 循环前缀 /后缀加入模块, 连接所述训练序列***模块, 用于在训练序列中加入循 环前缀 /后缀以消除码间串扰; 发射滤波模块, 连接所述循环前缀 /后缀加入模块, 用于对加 入循环前缀 /后缀后的信号进行滤波并发送至接收端;
接收端包括: 前端数据处理模块, 用于对从发送端接收的信号进行预处理, 包括色散 粗补偿、 载波频率恢复、 接收匹配滤波、 数字同步等, 然后发送至所述循环前缀 /后缀移除 模块; 循环前缀 /后缀移除模块, 用于移除训练序列中的循环前缀 /后缀; FFT模块, 连接所 述循环前缀 /后缀移除模块, 用于对移除循环前缀 /后缀的训练序列进行快速傅里叶变换, 将 其变换到频域; 信道传递函数估计模块, 连接所述 FFT模块, 用于除以训练序列对应的理 想频谱, 得到信道的传递函数; IFFT模块, 连接所述信道传递函数估计模块, 用于进行快 速傅里叶反变换(IFFT)将信号变换到时域, 得到时域滤波器抽头系数; FIR滤波器, 连接 所述 IFFT模块, 用于利用得到的时域滤波器抽头系数在时域对数据信号进行滤波以实现信 号均衡; 后端数据处理模块, 连接所述 FIR滤波器, 用于载波相位恢复; 判决模块, 连接 所述后端数据处理模块, 用于将接收的信号信息恢复成二进制数据。
图 4为 1.76Tb/s传输实验结果, 信号为 720公里的传输距离, 横轴为信号的入纤功率。 将本发明均衡方法的结果与时域均衡的常用算法 (常模算法 (CMA) 加上级联多模算法
(CMMA))进行对比, 结果显示本发明的均衡算法优于常用的时域均衡算法, 原因在于信 道的噪声对时域均衡算法的滤波器抽头估计有较大的影响。
以上实施例仅用以说明本发明的技术方案而非对其进行限制, 本领域的普通技术人员 可以对本发明的技术方案进行修改或者等同替换, 而不脱离本发明的精神和范围, 本发明 的保护范围应以权利要求所述为准。
Claims
1、 一种基于频域信道估计的均衡方法, 包括以下步骤:
1 ) 在发射端信号中***具有平坦的频谱特性的训练序列;
2)在接收端用快速傅里叶变换将接收的训练序列变换到频域, 然后通过与该训练序列 对应的理想频谱相除得到信道的传递函数, 取该传递函数的倒数并将其用快速傅里叶反变 换变换到时域, 得到时域滤波器抽头系数;
3 ) 利用所述时域滤波器抽头系数在时域对数据信号进行滤波, 实现信号均衡。
2、 如权利要求 1所述的方法, 其特征在于: 所述训练序列为 M序列或 chu序列。
3、 如权利要求 1 所述的方法, 其特征在于: 所述发射端在所述训练序列中加入循环前缀 / 后缀以消除码间串扰; 所述接收端先移除接收到的训练序列中的循环前缀 /后缀, 然后进行 所述快速傅里叶变换。
4、 如权利要求 1所述的方法, 其特征在于: 所述接收端对由发射端接收的信号首先进行前 端数据处理, 包括色散粗补偿、 载波频率恢复、 接收匹配滤波和数字同步; 并在步骤 3 )之 后进行后端数据处理, 包括载波相位恢复。
5、 如权利要求 1所述的方法, 其特征在于: 在发射端的信号成帧传输, 每一帧的帧结构包 含两个偏振方向, 每个偏振方向均包含训练序列与数据信号, 训练序列由成对的部分组成, 标记为 ^和^, 在时间上交替排列, 并且:
其中 tx和 ^为 M序列或 chu序列, "0"表示长度与 chu序列等长的数值为 0的序列。
6、 如权利要求 5所述的方法, 其特征在于: 训练序列长度的选择由信道载波频率偏移和相 位的飘移程度决定; 训练序列个数的选择由信道中自发辐射噪声强度决定; 数据信号长度 的选择由信道传递函数的飘变程度决定。
7、 一种基于频域信道估计的均衡***, 包括发射端和接收端, 其特征在于,
所述发射端包括:
训练序列***模块, 用于在发射端信号中***具有平坦的频谱特性的训练序列; 循环前缀 /后缀加入模块, 连接所述训练序列***模块, 用于在训练序列中加入循环前 缀 /后缀以消除码间串扰;
发射滤波模块, 连接所述循环前缀 /后缀加入模块, 用于对加入循环前缀 /后缀后的信号 进行滤波并发送至通信信道;
所述接收端包括:
循环前缀 /后缀移除模块, 用于移除训练序列中的循环前缀 /后缀;
FFT模块, 连接所述循环前缀 /后缀移除模块, 用于对移除循环前缀 /后缀的训练序列进 行快速傅里叶变换, 将其变换到频域;
信道传递函数估计模块, 连接所述 FFT模块, 用于与训练序列对应的理想频谱相除, 得到信道的传递函数;
IFFT模块, 连接所述信道传递函数估计模块, 用于进行快速傅里叶反变换 (IFFT) 将 信号变换到时域, 得到时域滤波器抽头系数;
FIR滤波器, 连接所述 IFFT模块, 用于利用得到的时域滤波器抽头系数在时域对数据 信号进行滤波以实现信号均衡。
8、 如权利要求 7所述的***, 其特征在于, 还包括:
前端数据处理模块, 用于对从发送端接收的信号进行预处理, 然后发送至所述循环前 缀 /后缀移除模块;
后端数据处理模块, 连接所述 FIR滤波器, 用于载波相位恢复。
9、 如权利要求 8所述的***, 其特征在于, 所述预处理包括: 色散粗补偿、载波频率恢复、 接收匹配滤波、 数字同步。
10、 如权利要求 8所述的***, 其特征在于, 还包括判决模块, 连接所述后端数据处理模 块, 用于将接收的信号信息恢复成二进制数据。
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CN103716265B (zh) * | 2014-01-07 | 2017-05-03 | 电子科技大学 | 一种相位噪声补偿抑制改进方法 |
CN103812806B (zh) * | 2014-02-24 | 2017-10-10 | 北京大学 | 一种基于时域信道估计的信道均衡方法和*** |
CN104901906B (zh) * | 2014-03-07 | 2019-11-05 | 中兴通讯股份有限公司 | 一种相干光通信信道估计方法和*** |
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CN108259091B (zh) * | 2016-12-29 | 2020-02-14 | 华为技术有限公司 | 一种时域滤波装置方法和装置 |
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CN108737310B (zh) * | 2017-04-25 | 2021-06-15 | 华为技术有限公司 | 处理信号的方法和装置 |
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CN112564816B (zh) * | 2020-11-04 | 2022-03-08 | 中山大学 | 一种基于时域迭代的单边带信号恢复算法 |
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CN116935906A (zh) * | 2022-04-04 | 2023-10-24 | 澜起电子科技(昆山)有限公司 | 用于存储***接口电路的信号处理方法和装置 |
CN115173957B (zh) * | 2022-07-08 | 2023-11-24 | 聊城大学 | Svdd***中rsop、cd、eepn联合均衡方法 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1325190A (zh) * | 2000-05-18 | 2001-12-05 | 华为技术有限公司 | 一种用于信道辨识和符号同步的综合方法 |
EP1294150A2 (en) * | 2001-09-18 | 2003-03-19 | Thomson Licensing S.A. | Adaptive algorithm for the equaliser of a multicarrier receiver |
CN101237245A (zh) * | 2007-01-31 | 2008-08-06 | 展讯通信(上海)有限公司 | 基于td-scdma网络的单频广播接收方法 |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7042937B2 (en) * | 2001-04-23 | 2006-05-09 | Koninklijke Philips Electronics N.V. | Hybrid frequency-time domain equalizer |
CN1200521C (zh) * | 2003-06-18 | 2005-05-04 | 清华大学 | 用于频域均衡的导频***与信道参数估计的方法 |
-
2013
- 2013-06-27 CN CN201310263522.6A patent/CN103338171B/zh active Active
- 2013-08-13 WO PCT/CN2013/081341 patent/WO2014205893A1/zh active Application Filing
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1325190A (zh) * | 2000-05-18 | 2001-12-05 | 华为技术有限公司 | 一种用于信道辨识和符号同步的综合方法 |
EP1294150A2 (en) * | 2001-09-18 | 2003-03-19 | Thomson Licensing S.A. | Adaptive algorithm for the equaliser of a multicarrier receiver |
CN101237245A (zh) * | 2007-01-31 | 2008-08-06 | 展讯通信(上海)有限公司 | 基于td-scdma网络的单频广播接收方法 |
Non-Patent Citations (1)
Title |
---|
ZHENG, ZHENNAN ET AL.: "1.76TB/S NYQUIST PDM 16QAM SIGNAL TRANSMISSION OVER 714KM SSMF WITH THE MODIFIED SCFDE TECHNIQUE.", OPTICS EXPRESS., vol. 21, no. 15, 29 July 2013 (2013-07-29) * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN105187335A (zh) * | 2015-06-25 | 2015-12-23 | 华南理工大学 | 基于分组数据失真最小化的导频位置选择方法及装置 |
CN105187335B (zh) * | 2015-06-25 | 2018-04-13 | 华南理工大学 | 基于分组数据失真最小化的导频位置选择方法及装置 |
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