Method and system for decoding multilevel signals
    1.
    发明申请
    Method and system for decoding multilevel signals 有权
    解码多电平信号的方法和系统

    公开(公告)号:US20070171998A1

    公开(公告)日:2007-07-26

    申请号:US11633658

    申请日:2006-12-04

    IPC分类号: H04L25/06

    摘要: A multilevel optical receiver can comprise a plurality of comparators that generally correspond with the number of levels in a multilevel data stream. Each comparator can be individually controlled and fed a decision threshold in order to decode a multilevel signal. The multilevel optical receiver can generate a statistical characterization of the received symbols in the form of a marginal cumulative distribution function (CDF) or probability density function (pdf). This characterization can be used to produce a set of ε-support estimates from which conditional pdfs are derived for each of the transmission symbols. These conditional pdfs may then be used to determine decision thresholds for decoding the received signal. The conditional pdfs may further be used to continuously estimate the fidelity or error rate of the received signal without the transmission of a testing sequence. The ε-supports may further be used to automatically control the gain on the receiver.

    摘要翻译: 多电平光接收器可以包括多个比较器,其通常对应于多电平数据流中的电平数量。 可以对每个比较器进行单独控制并输入判定阈值,以解码多电平信号。 多级光接收机可以以边际累积分布函数(CDF)或概率密度函数(pdf)的形式生成接收符号的统计特征。 该表征可以用于产生一组epsilon支持估计,从每个传输符号导出条件pdf。 然后可以使用这些条件pdf来确定用于解码接收信号的判定阈值。 条件pdf还可用于连续估计接收信号的保真度或错误率,而不传输测试序列。 还可以使用epsilon支持来自动控制接收机上的增益。

    Adaptive noise filtering and equalization for optimal high speed multilevel signal decoding

    公开(公告)号:US20060239390A1

    公开(公告)日:2006-10-26

    申请号:US11358901

    申请日:2006-02-21

    IPC分类号: H04B1/10

    摘要: A Signal Conditioning Filter (SCF) and a Signal Integrity Unit (SIU) address the coupled problem of equalization and noise filtering in order to improve signal fidelity for decoding. Specifically, a received signal can be filtered in a manner to optimize the signal fidelity even in the presence of both significant (large magnitudes of) ISI and noise. The present invention can provide an adaptive method that continuously monitors a signal fidelity measure. Monitoring the fidelity of a multilevel signal can be performed by external means such as by the SIU. A received signal y(t) can be “conditioned” by application of a filter with an electronically adjustable impulse response g(t). A resulting output z(t) can then be interrogated to characterize the quality of the conditioned signal. This fidelity measure q(t) can be used to adjust the filter response to maximize the fidelity measure of the conditioned signal.

    Increasing data throughput in optical fiber transmission systems
    3.
    发明申请
    Increasing data throughput in optical fiber transmission systems 失效
    增加光纤传输系统中的数据吞吐量

    公开(公告)号:US20070222654A1

    公开(公告)日:2007-09-27

    申请号:US11599835

    申请日:2006-11-15

    IPC分类号: H03M1/66

    摘要: Data throughput rates are increased in an optical fiber communication system without requiring replacement of the existing optical fiber in a link. Channel throughput is increased by upgrading the components and circuitry in the head and terminal of an optical fiber communication system link. Aggregate throughput in a fiber optic link is increased beyond the range of conventional Wavelength Division Multiplexed (WDM) upgrades, while precluding the necessity of replacing existing fiber plants. The increase in system throughput is achieved by using advanced modulation techniques to encode greater amounts of data into the transmitted spectrum of a channel, thereby increasing the spectral efficiency of each channel. This novel method of increasing transmission capacity by upgrading the head and terminal of the system to achieve greater spectral efficiency and hence throughput, alleviates the need to replace existing fiber plants. Spectrally efficient complex modulation techniques can be supported by interface circuits with an increased level of signal processing capability in order to both encode multiple bits into a transmitted symbol and decode the original data from the received symbols.

    摘要翻译: 数据吞吐率在光纤通信系统中增加,而不需要更换链路中现有的光纤。 通过升级光纤通信系统链路的头端和终端中的组件和电路来增加信道吞吐量。 光纤链路中的总吞吐量增加超出常规波分复用(WDM)升级的范围,同时排除了替换现有光纤设备的必要性。 系统吞吐量的增加通过使用先进的调制技术将更大量的数据编码到信道的传输频谱中,从而提高每个信道的频谱效率来实现。 这种通过升级系统的头部和终端来提高传输容量以实现更高的频谱效率和因此的吞吐量的这种新颖的方法减轻了替换现有的光纤设备的需要。 频谱效率高的复调制技术可以由具有增加的信号处理能力水平的接口电路来支持,以便将多个比特编码到发射符号中并且从接收的符号解码原始数据。

    Multilevel pulse position modulation for efficient fiber optic communication
    4.
    发明申请
    Multilevel pulse position modulation for efficient fiber optic communication 失效
    用于高效光纤通信的多电平脉冲位置调制

    公开(公告)号:US20070092265A1

    公开(公告)日:2007-04-26

    申请号:US11543693

    申请日:2006-10-05

    IPC分类号: H04B10/04

    摘要: Decreasing the average transmitted power in an optical fiber communication channel using multilevel amplitude modulation in conjunction with Pulse Position Modulation (PPM). This multilevel PPM method does not entail any tradeoff between decreased power per channel and channel bandwidth, enabling a lower average transmitted power compared to On/Off Keying (OOK) with no reduction in aggregate data rate. Therefore, multilevel PPM can be used in high-speed Dense Wavelength Division Multiplexed (DWDM) systems where the maximum number of channels is traditionally limited by nonlinear effects such as self-phase modulation (SPM), cross-phase modulation (XPM), four-wave mixing (FWM), stimulated Brillouin scattering (SBS), and stimulated Raman scattering (SRS). This modulation technique can enable an increased number of channels in DWDM systems, thereby increasing aggregate data rates within those systems.

    摘要翻译: 结合脉冲位置调制(PPM),降低使用多电平幅度调制的光纤通信信道中的平均发射功率。 这种多级PPM方法不需要在每个通道的功率减少与通道带宽之间进行权衡,与开/关键控(OOK)相比,能够实现较低的平均传输功率,而不会降低总体数据速率。 因此,多电平PPM可用于高速密集波分复用(DWDM)系统,其中最大通道数传统上受非线性影响的限制,如自相位调制(SPM),交叉相位调制(XPM),四 波混频(FWM),受激布里渊散射(SBS)和受激拉曼散射(SRS)。 这种调制技术可以实现DWDM系统中增加的信道数量,从而提高这些系统内的总体数据速率。