激光与红外
激光與紅外
격광여홍외
LASER & INFRARED
2015年
5期
559-563
,共5页
紫外光通信%脉冲展宽%码间串扰%符号速率%误码率
紫外光通信%脈遲展寬%碼間串擾%符號速率%誤碼率
자외광통신%맥충전관%마간천우%부호속솔%오마솔
ultraviolet communication%pulse broadening%intersymbol interference%symbol rate%BER
紫外激光散射通信会引起严重的脉冲展宽效应，由此导致的码间串扰会引起通信误码率。利用紫外光传输模型计算接收信号的时域分布；对“1”码和“0”码包络的概率密度分布按照“11”、“10”、“01”和“00”组合进行卷积，得到在采样时刻两侧相邻码元串扰量的概率密度函数。在引起误码临界值到采样时刻串扰量范围内，对概率密度函数进行积分可得上述4种情况的串扰引起误码的概率。仿真结果表明：距离5 km 的直视通信符号速率须小于9.25×107 Baud；距离1 km 的非直视通信在收发端仰角同为20°、30°和40°时，对应的符号速率须小于4.0×107 Baud、6.0×106 Baud 和3.6×105 Baud。因此，若紫外激光用于低速无线光通信领域可忽略码间串扰的影响。
紫外激光散射通信會引起嚴重的脈遲展寬效應，由此導緻的碼間串擾會引起通信誤碼率。利用紫外光傳輸模型計算接收信號的時域分佈；對“1”碼和“0”碼包絡的概率密度分佈按照“11”、“10”、“01”和“00”組閤進行捲積，得到在採樣時刻兩側相鄰碼元串擾量的概率密度函數。在引起誤碼臨界值到採樣時刻串擾量範圍內，對概率密度函數進行積分可得上述4種情況的串擾引起誤碼的概率。倣真結果錶明：距離5 km 的直視通信符號速率鬚小于9.25×107 Baud；距離1 km 的非直視通信在收髮耑仰角同為20°、30°和40°時，對應的符號速率鬚小于4.0×107 Baud、6.0×106 Baud 和3.6×105 Baud。因此，若紫外激光用于低速無線光通信領域可忽略碼間串擾的影響。
자외격광산사통신회인기엄중적맥충전관효응，유차도치적마간천우회인기통신오마솔。이용자외광전수모형계산접수신호적시역분포；대“1”마화“0”마포락적개솔밀도분포안조“11”、“10”、“01”화“00”조합진행권적，득도재채양시각량측상린마원천우량적개솔밀도함수。재인기오마림계치도채양시각천우량범위내，대개솔밀도함수진행적분가득상술4충정황적천우인기오마적개솔。방진결과표명：거리5 km 적직시통신부호속솔수소우9.25×107 Baud；거리1 km 적비직시통신재수발단앙각동위20°、30°화40°시，대응적부호속솔수소우4.0×107 Baud、6.0×106 Baud 화3.6×105 Baud。인차，약자외격광용우저속무선광통신영역가홀략마간천우적영향。
Pulse broadening caused by ultraviolet scattering communication may result in intersymbol interference (ISI)which can result in bit-error-rate(BER).It is studied the influence of pulse broadening on bit error rate of ultra-violet communication.Firstly,time domain distribution of received signal is calculated by ultraviolet transmission mod-el.Secondly,probability density distributions of different combinations of code ‘1 ’and code ‘0’are convolved ac-cording to the rules of ‘1 1 ’,‘1 0’,‘01 ’and ‘00’respectively,and then probability density distributions of ISI quan-tity caused by adjacent codes at both sides are obtained at sampling time.BER of the 4 cases caused by ISI is compu-ted by an integral of ISI quantity probability density distributions within the bounds of ISI quantity at sampling time and critical value of ISI which causes BER.Simulation results show that the symbol rate should be lower than 1 .36 × 1 08 Baud by LOS communication at a distance 5 km.By NLOS communication at distance 1 km,when elevations of transmitter and receiver are 20°,30°and 40°respectively,its corresponding symbol rates should be lower than 4.0 × 1 07 Baud,6.0 ×1 06 Baud and 3.6 ×1 05 Baud.As a result,BER caused by ISI can be ignored when ultraviolet is used for low speed wireless optical communication.
