多脉冲位置调制(multi-pulse position modulation,MPPM)与脉冲位置调制相比具有能量信息效率高和带宽低的优点,是水下激光通信中一种有效的通信方式。为了研究时钟抖动对激光水下多脉冲位置调制通信的误码影响,在分析MPPM时钟抖动时的性能的基础上,通过理论计算提出了MPPM最小误比特率的映射列表的方法,分析并仿真了MPPM使用二进制码和格雷码两种编码方式的误比特率。结果表明,在相同的传输带宽和传输速率下,使用格雷码编码的MPPM误码性能优于二进制编码,且MPPM的性能优于脉冲位置调制,误比特率降低约2.4dB。该研究结果对提高水下激光通信性能具有一定的理论参考价值。

Multi-pulse position modulation(MPPM)is more effective than pulse position modulation(PPM)in underwater laser communication due to its advantages of high efficiency and low bandwidth.In order to study the effect of imperfect slot synchronization on bit error of MPPM in underwater laser communication,a method of MPPM map table with the smallest bit error rate was put forward after analyzing MPPM performance with imperfect slot synchronization performance is analyzed.Bit error rate of MPPM based on binary code was compared with that based on Gray code by means of simulation.The result showed that bit error rate of Gray code was lower than that of binary code at the same bandwidth and transmit rate with the bit error rate declined about 2.4dB.The obtained results are theoretic reference to the improvement of the performance of underwater laser communication.