卫星振动对星间光码分多址系统性能的影响

卫星振动是影响星间光CDMA通信系统性能的一个重要因素.考虑多用户干扰、背景光噪音、热噪音、接收机噪音和卫星振动,给出了基于PPM信号格式的星间二维光CDMA通信系统的系统模型.采用数值分析的方法,详细分析了卫星振动对该系统误码率性能的影响.结果表明,码速率、通信波长和卫星振动都会影响星间二维光CDMA通信系统的误码率性能.当卫星振动标准偏差σ≤4×10－7时,卫星振动对系统误码率性能的影响较小；当卫星振动标准偏差σ≥1.2×10－6,卫星振动对系统误码率性能的影响很大,得到的误码率难以满足系统的通信要求,需要采用卫星振动抑制或补偿等技术提高星间二维光CDMA通信系统的误码率性能.

Influence of Satellite Vibration on the Performance of Inter-Satellite Optical CDMA Communication System

Satellite vibration was one of important factors which affected the performance of inter-satellite optical CDMA communication system. Considering the effects of multi-user interference,atmospheric scintillation,avalanche photodiode detector (APD) noise,thermal noise,and satellite vibration,the system model of intersatellite two-dimensional optical CDMA communication system with PPM signal format was presented,and the influence of satellite vibration on the bit error rate of this system was analyzed in detail.The results show that the wavelength,bit rate and satellite vibration could affect the bit error rate of intersatellite two-dimensional optical CDMA communication system all together. In the two-dimensional optical CDMA communication system which bit rate was 622 Mbps and wavelength was 1550 nm,when the standard variance was small (σ≤4 ×10－7),it couldn't affect the bit error rate of this communication system severely. Otherwise,when the normal variance was large (σ≥l. 2×10－6),the bit error rate couldn't satisfy the requirement of communication. Some methods needed to be used to suppress the influences of satellite vibration on the bit error rate of inter-satellite two-dimensional optical CDMA communication system.