基于频域窄带莱斯噪声消除机制的OFDM网络信号发射精度增强算法

Signal Enhancement Algorithm of OFDM Network Based on Frequency Domain Narrowband Noise Cancellation

为改善当前OFDM网络信号精度增强算法中难以高效消除频域窄带莱斯噪声,且系统误码率较高的不足,提出了一种基于频域窄带莱斯噪声消除机制的OFDM网络信号精度增强算法.首先,基于128频相移键控调制方法,在获取信号时域特征的基础上,引入快速傅里叶变换,对信号进行离散化,并基于信号投影机制,构建正交星座图,实现信号投影矢量在预发射状态下的正交分层排序,消除了信源状态下频域窄带莱斯噪声对系统的干扰;随后,引入快速傅里叶逆变换,对预发射信号进行加密处理,且通过量化评估模型对信号精度进行优化提升,有效节约了传输带宽,提高了信号发射性能,改善了信道抗衰落效果.仿真实验表明,与当前常见的时间窗消除机制(time window elimination mechanism, TWE)、频率拓扑映射机制(frequency topology mapping, FT)相比,本文算法的误码率更低,且具有更高的信号增益效果.

In order to improve the accuracy of OFDM network signal lifting algorithm is difficult to erase the high frequency narrow band Rician noise and high error rate, signal gain strength is difficult to reach the ideal state, presents a lifting algorithm of OFDM network signal precision frequency domain narrowband Rician noise erasing mechanism based on. Based on the 128 frequency phase shift keying modulation, based on obtaining the signal on the use of the fast Fourier transform of discrete signals, and the signal based on orthogonal projection method to realize signal constellation, projection vector in the pre-launch condition orthogonal layer sorting, eliminate the interference source under the condition of Frequency Domain Narrowband the Rician noise on the system;then the fast Fourier transform based on pre launch signal is encrypted, and through the quantitative model of error evaluation mechanism of signal precision is further improved, greatly save the transmission bandwidth, improve the signal transmission performance, this algorithm improves the channel fading effect. Simulation results show that the time window algorithm and the common elimination mechanism(Time Window Elimination Mechanism TWE mechanism), frequency topology mapping mechanism(Frequency topology mapping FT mechanism) compared to the bit error rate of the system is low, and has a good signal gain effect, which is of great value in practice.