无线光FDAPIM-CDMA系统性能分析  

Performance Analysis of Optical Wireless FDAPIM-CDMA Systems

作　　者：黄爱萍[1] 樊养余[1] 李伟[1] 王凤琴[1] 

机构地区：[1]西北工业大学电子信息学院,陕西西安710129

出　　处：《中国激光》2010年第7期1772-1776,共5页Chinese Journal of Lasers

基　　金：空间微波技术国家级重点实验室基金项目(9140C5301010701);陕西省自然科学基金项目(2007F10)资助课题

摘　　要：在无线光通信中,为了提高系统的性能,提出了一种新的定长双幅度数字脉冲间隔调制码分多址方式(FDAPI M-CDMA)。分析了采用光正交码时,它在多用户同步和理想异步干扰下的误码率(BER)特性,并给出了误码率上限和下限的数学表达式。研究了码长、码重、用户总数以及接收门限对系统性能的影响,并在相同情况下与开关键控码分多址(OOK-CDMA)系统的性能进行了比较。理论分析与仿真结果表明,FDAPI M-CDMA系统的误码率性能随码长的增大、用户数量的减少而提高。对于过长的码重,可通过增加接收门限值来降低误码率。当符号比特数大于等于6且门限值等于码重时,FDAPI M-CDMA的误码率上限和下限均比OOK-CDMA小,具有较强的抗多用户干扰能力。因此FDAPI M-CDMA可作为OOK-CDMA的一个有效的替代方式。In order to improve the performance of optical wireless communication system,a novel fixed length dual-amplitude pulse interval modulation-code division multipte access（FDAPIM-CDMA） is proposed.With the optical orthogonal codes（OOC）,the bit error rate（BER） of the proposed system in chip synchronous interference and ideal chip asynchronous interference are analyzed respectively.The upper and lower bounds on BER are derived as a function of code length,code weight,number of users,and receiver threshold.The characteristics for a variety of system parameters are discussed and compared with on-off keying-code division multiple access（OOK-CDMA）.Simulations show that the BER performance of the proposed system can be improved by longer code length and smaller number of users.It is effective to get the threshold level higher to improve the system performance when the code weight is larger.Moreover,both the upper and lower bounds on BER of FDAPIM-CDMA are lower than those of OOK-CDMA when the bits per symbol are not less than 6.Hence,FDAPIM-CDMA plays good performance in multi-user interference and is superior in wireless optical communications system.

关 键 词：无线光通信 FDAPIM-CDMA 误码率上限/下限 多用户干扰 光正交码 

分 类 号：TN929.1[电子电信—通信与信息系统]