基于分数间隔均衡的变步长双模式盲均衡算法

Variable Step Size Dual-Mode Blind Equalization Algorithm Based on Fractional Spaced Equalizer

大功率光源和高灵敏度探测器的带宽限制及海水信道多径效应引起的信号码间干扰严重影响了水下无线光通信(UWOC)系统的性能。针对该问题,提出了一种基于分数间隔均衡的反双曲正弦函数变步长双模式盲均衡算法。该算法将可变步长常数模分数间隔均衡算法和判决引导最小均方分数间隔均衡算法的输出结果根据混合参数进行凸组合,并通过迭代产生新的混合参数,以保证两种均衡算法的自适应切换,且切换的阈值不需要人为设定。该算法在保证快速收敛的情况下具有较小的均方误差,同时也不需要占用额外的带宽。仿真结果表明,双模式盲均衡算法在各种信噪比下均可快速收敛,且能有效降低稳态均方误差,抑制码间干扰,改善UWOC系统的误码性能。

The bandwidth limitation of highpower light sources and highsensitivity detectors,as well as the signal intersymbol interference caused by the multipath effect of seawater channels,seriously affect the performance of underwater wireless optical communication(UWOC)systems.Aiming at this problem,an inverse hyperbolic sinusoidal function variable step size dualmode blind equalization algorithm based on fractional spaced equalizer is proposed in this paper.The algorithm combines the variable step size constanttomode fractional spaced equalizer algorithm and the decision directed least mean square modefractional spaced equalizer algorithm through the mixed parameters for convex combination,and iteratively updates the mixed parameters to achieve the adaptive switching between the two equalization algorithms does not need to manually set the switching threshold,and has a small mean square error under the condition of ensuring rapid convergence,and at the same time,it does not need to occupy additional bandwidth.The simulation results show that the dualmode blind equalization algorithm can quickly converge under various signaltonoise ratios,reduce the steadystate mean square error,effectively suppress intersymbol interference,and improve UWOC systems error performance.