共查询到17条相似文献,搜索用时 90 毫秒
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讨论了直扩码分多址(DS-CDMA)系统和多载波码分多址(MC-CDMA)系统的结构,给出两者关系,比较了两者的系统特性以及它们的系统容量,并且将比特误码性能加以分析。 相似文献
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描述了两跳MIMO(Multiple- input and Multiple- output)中继系统模型,概述了中继通用的转发策略以及系统性能分析常涉及到的信道模型和信源发射方案,详细介绍了两跳MIMO中继系统通信性能分析国内外的研究进展,通过一个具体的例子比较了不同发射策略系统的性能,最后探讨和展望了两跳MIMO中... 相似文献
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《Lightwave Technology, Journal of》1997,15(3):452-457
Performance of optical asynchronous code-division multiple-access (CDMA) systems with double optical hard-limiters is analyzed under the assumption of Poisson shot noise model for the receiver photodetector where the noise due to the detector dark currents exists. Optical orthogonal codes (OOC's) are employed as signature sequence codes. In the analysis, chips are assumed to be synchronous among users, that is, the chip synchronous case, because the effect of the interference is largest in the chip synchronous case and thus the performance in the chip synchronous case results in the upper bounds on the performance of the asynchronous system. The performance is evaluated under average power and bit rate constraints. The results show that, differing from the optical synchronous CDMA systems with double optical hard-limiters, the optical asynchronous CDMA systems with double optical hard-limiters have good performance even when the number of simultaneous users is large 相似文献
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二维光纤码分多址通信系统 总被引:5,自引:1,他引:5
介绍了三种二维光纤码分多址(OCDMA)系统。分析表明,它们的性能都优于一维OCDMA。同时也比较了WDM+OCDMA和多波长OCDMA系统的性能。 相似文献
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We analyze the bit error rate (BER) of coherent optical code-division multiple-access (CDMA) communication systems with a transfer function matrix (TFM). The coherent optical CDMA is a promising system for an access network due to its advantages of asynchronous transmission, information security, multiple-access capability. TFM is defined as the Fourier transform of the impulse response of an optical fiber, which interconnects each CDMA system. TFM has parameters such as the state of polarization (SOP), phase difference, power distribution between two orthogonal modes over an optical frequency range. We first analyze the statistic of a received signal via an optical fiber with TFM, and then apply the statistic to the BER analysis. The analytical results show that BER increases with the bandwidth of a signal, and that selecting a proper center frequency leads to the BER reduction. 相似文献
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1 IntroductionInrecentyears,therehasbeenincreasinginter estinthestudyofOCDMAcommunicationsystemswithoneortwoopticalhard limiters .DifferentOCDMAsystemsintroducingoneortwoopticalhard limitershavebeen presented[1~3] .Itshowsthatintroducingoneortwoopticalhard … 相似文献
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Liren Zhang Chih‐Hong Eyoh Chee‐Hock Ng 《International Journal of Communication Systems》2001,14(8):803-812
An ATM transit switch is proposed based on direct sequence optical code division multiple access technique. No buffering is necessary to facilitate the switching. Code conversion is used instead to emulate the switching function. The switch not only provides asynchronous access to the users but also has a limited capability of dynamic bandwidth allocation. It is free from timing jitters and switching delay is significantly reduced. A look‐up table is employed in the switching and updated through network management functions. The switch provides a new approach to asynchronous cross‐connection in the ATM core network. The performance of the new switch is evaluated by a set of prime codes and modified prime codes. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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