由于长距离光传输系统中常使用的线性复用技术,常将非线性视为一种干扰因素。非线性频分复用(Nonlinear Frequency Division Multiplexing,NFDM)近年来受到广泛关注,这种技术在非线性傅立叶域中对数据进行调制,被视为克服克尔非线性的...由于长距离光传输系统中常使用的线性复用技术,常将非线性视为一种干扰因素。非线性频分复用(Nonlinear Frequency Division Multiplexing,NFDM)近年来受到广泛关注,这种技术在非线性傅立叶域中对数据进行调制,被视为克服克尔非线性的一种潜在方法。本文详细介绍了相干光NFDM的理论推导和传输过程,并描述了b系数调制的概念和优化设计。在本文中,使用训练序列来实现基于b系数调制的NFDM系统的信道估计,并通过蒙特卡洛仿真进行验证。基于改进后的b系数调制方法相比于传统b系数调制方法具有更低的误码率并且可以传输更远的距离。此外,它的性能明显优于传统的调制反射系数的方法。展开更多
The traditional fractional frequency offset(FFO) estimation schemes for orthogonal frequency division multiplexing(OFDM) in non-cooperative communication have the problems of susceptible performance with the frequency...The traditional fractional frequency offset(FFO) estimation schemes for orthogonal frequency division multiplexing(OFDM) in non-cooperative communication have the problems of susceptible performance with the frequency offset values and the number of OFDM symbols,a novel fractional frequency offset blind estimation scheme based on EKF for OFDM systems is conceived.The nonlinear function of the frequency offset is calculated by employing the correlation.And then the frequency offset is estimated by means of the iterative algorithm of EKF.The finally fractional frequency offset is estimated by adopting repeated the above process.Simulation results demonstrate that the proposed scheme is robust to the frequency offset values without any requirements of a prior knowledge.展开更多
Orthogonal frequency division multiplexing(OFDM)produces a high peak-to-average power ratio(PAPR) that adversely affects high-speed OFDM data transmission. In order to reduce the high PAPR, an efficient nonlinear comp...Orthogonal frequency division multiplexing(OFDM)produces a high peak-to-average power ratio(PAPR) that adversely affects high-speed OFDM data transmission. In order to reduce the high PAPR, an efficient nonlinear companding transform(NCT) function is proposed. With the proposed NCT function,the compression and expansion weights can be applied independently with suitably chosen function parameter values. As a result, the proposed function can easily maintain the average signal power approximately unchanged during the companding process.In this regard, the proposed function is superior to previously proposed schemes. Also, the simulations show the outstanding PAPR reduction performance of the proposed function. It is demonstrated that the proposed scheme performs well with nonlinear transmitter amplifiers and delivers superior error performance, compared with error function and exponential function based schemes.展开更多
文摘由于长距离光传输系统中常使用的线性复用技术,常将非线性视为一种干扰因素。非线性频分复用(Nonlinear Frequency Division Multiplexing,NFDM)近年来受到广泛关注,这种技术在非线性傅立叶域中对数据进行调制,被视为克服克尔非线性的一种潜在方法。本文详细介绍了相干光NFDM的理论推导和传输过程,并描述了b系数调制的概念和优化设计。在本文中,使用训练序列来实现基于b系数调制的NFDM系统的信道估计,并通过蒙特卡洛仿真进行验证。基于改进后的b系数调制方法相比于传统b系数调制方法具有更低的误码率并且可以传输更远的距离。此外,它的性能明显优于传统的调制反射系数的方法。
基金supported by the National Natural Science Foundation of China under Grant No.61501348 and 61271299China Postdoctoral Science Foundation funded project under Grant No.2014M562372+1 种基金Natural Science Basic Research Plan in Shaanxi Province of China under Grant No.2016JQ6039the 111 Project under Grant No.B08038
文摘The traditional fractional frequency offset(FFO) estimation schemes for orthogonal frequency division multiplexing(OFDM) in non-cooperative communication have the problems of susceptible performance with the frequency offset values and the number of OFDM symbols,a novel fractional frequency offset blind estimation scheme based on EKF for OFDM systems is conceived.The nonlinear function of the frequency offset is calculated by employing the correlation.And then the frequency offset is estimated by means of the iterative algorithm of EKF.The finally fractional frequency offset is estimated by adopting repeated the above process.Simulation results demonstrate that the proposed scheme is robust to the frequency offset values without any requirements of a prior knowledge.
基金supported by the Research Grant of BB(Brain Busan)21 Project of 2015
文摘Orthogonal frequency division multiplexing(OFDM)produces a high peak-to-average power ratio(PAPR) that adversely affects high-speed OFDM data transmission. In order to reduce the high PAPR, an efficient nonlinear companding transform(NCT) function is proposed. With the proposed NCT function,the compression and expansion weights can be applied independently with suitably chosen function parameter values. As a result, the proposed function can easily maintain the average signal power approximately unchanged during the companding process.In this regard, the proposed function is superior to previously proposed schemes. Also, the simulations show the outstanding PAPR reduction performance of the proposed function. It is demonstrated that the proposed scheme performs well with nonlinear transmitter amplifiers and delivers superior error performance, compared with error function and exponential function based schemes.
