基于光OFDM信号导频功率分配优化的信道估计研究

Channel estimation based on optical OFDM signal pilot power allocation optimization

针对光通信传输时会受到色散和衰减的影响,传输过程中融合拥有高频谱率和抗干扰色散等特性的新技术—正交频分复用(OFDM)技术,可以有效地减弱各种干扰影响.结合Matlab、OptiSystem仿真平台与导频信道估计技术,建立直接检测光OFDM系统仿真模型,设计5种功率分配优化方案并开展仿真试验研究.结果表明:当导频功率随频率增加而递增时,OFDM信号的误码率(BER)性能最优,功率随频率增加而递减时OFDM信号的BER性能最差;频率增加而导频功率先递减后递增的分配方式最佳,等功率的分配方式最差.导频功率分配时,在信道状况相对较差的高频和低频处适当增加导频功率可有效抑制衰减和干扰,系统性能处于最佳状态.

For optical communication transmission will be affected by dispersion and attenuation. In the transmission process, a new technology with high spectral rate and anti-interference dispersion, Orthogonal Frequency Division Multiplexing (OFDM) technology, can effectively reduce various interference effects. Combined with Matlab, OptiSystem simulation platform and pilot channel estimation technology, the simulation model of direct detection optical OFDM system is established, five power allocation optimization schemes are designed and simulation experiments are carried out. The results showed that: When the pilot power increases with increasing frequency, the error rate (BER) performance of the OFDM signal is optimal. BER performance of OFDM signal is the worst when power decreases with increasing frequency. The best way to distribute as the pilot power is first decremented and then incremented as frequency increases. And the equal power distribution is the worst. When the pilot power is allocated, the attenuation and interference can be effectively suppressed by appropriately increasing the pilot power at the high frequency and low frequency of the channel, and the system performance is in an optimal state.