CC-CDMA的码构造及系统设计方法

发布时间：2018-01-01 20:16

本文关键词：CC-CDMA的码构造及系统设计方法　出处：《哈尔滨工业大学》2016年博士论文　论文类型：学位论文

【摘要】：在无线通信系统中,多址技术决定了用户如何共享系统的频谱资源。得益于其优异的特性,码分多址在第二代和第三代移动通信系统中获得广泛应用。在码分多址无线通信系统中,扩频码的相关特性至关重要,拥有理想相关特性的扩频码可以大大简化系统的复杂度,并且可获得完全频谱利用效率。然而,具有一维结构的传统扩频码无法实现理想的相关特性,使得传统码分多址无线通信系统必须依赖复杂的辅助子系统,如开环／闭环功率控制、Rake接收机、速率匹配、上行链路同步控制等。不同于传统扩频码,具有二维结构的互补码可以实现理想的相关特性,于是提出用于构建下一代码分多址无线通信系统。互补码的理想相关特性使得基于互补码的下一代码分多址技术不再受多径和多址干扰影响,从而摆脱传统码分多址无线通信系统中的各种复杂的辅助子系统,因此,是未来蜂窝移动通信系统中富有竞争力的技术之一。另外,在国防和航天等特殊领域,互补码的理想相关特性也使得基于互补码的码分多址技术具有极大的应用价值。尽管研究人员已验证在高斯白噪声信道和平坦慢衰落信道环境下基于互补码的码分多址(CC-CDMA)无线通信系统不受多用户干扰影响,但由于互补码的二维结构,频率选择性慢衰落信道使得CC-CDMA无线通信系统面临着巨大的挑战。另一方面,互补码的集大小决定了CC-CDMA无线通信系统可支持的最大用户个数,然而具有理想相关特性的互补码的集大小较小,会限制CC-CDMA无线通信系统的实际应用。因此,本文主要围绕这两个方面展开研究,重点研究了频率选择性慢衰落信道下的检测算法、抗信道频率选择衰落的互补码的构造方法及传输系统、以及可以支持更多用户的互补码的构造方法及传输系统,研究结果对于CC-CDMA无线通信系统的实际应用具有重要价值。具体研究内容和成果如下：针对采用理想相关互补码和传统相关检测接收机的CC-CDMA无线通信系统进行研究。首先描述了两种具有理想相关特性的互补码——完全互补码和超级互补码的产生方法。接下来,基于子信道平坦衰落的信道模型和收发机模型,建立了接收机相关检测前子信道输出信号的向量表达形式。然后,基于各子信道输出的接收向量,分析了平坦慢衰落信道、频率选择性慢衰落信道、平坦快衰落信道、以及码片不同步情况下采用理想相关互补码和传统相关检测接收机的CC-CDMA无线通信系统的性能。分析和仿真结果表明,信道的频率选择性衰落和时间选择性衰落会破坏用户间的正交性,引入多用户干扰。针对频率选择性慢衰落信道下CC-CDMA无线通信系统中的检测算法进行研究,分别为下行通信和上行通信提出了基于最小均方误差准则的单用户检测算法和多用户检测算法。对于下行通信,基于单用户检测接收机结构,提出了子载波级MMSE和用户级MMSE单用户检测算法,相比于正交恢复合并和最大比合并检测算法,它们既不是噪声受限的,也不是干扰受限的。对于上行通信,基于多用户检测接收机结构,提出了子载波联合MMSE-MUD和子载波独立MMSE-MUD多用户检测算法。仿真结果验证了基于最小均方误差的单用户检测接收机和多用户检测接收机具有优异的误码率性能。针对频率选择性慢衰落信道下互补码的构造进行研究,提出了抗频选互补码及其传输系统。首先讨论了不受信道频率选择性衰落影响的互补码的特征,提出了借助Golay互补对构造抗频选互补码的方法,并分析了它的相关特性。其次,针对下行通信,提出了基于抗频选互补码的发射机和接收机结构,分析和仿真结果验证了基于抗频选互补码的CDMA下行通信系统中无多用户干扰。针对上行通信,提出了基于抗频选互补码的发射机和接收机结构,分析和仿真结果同样表明基于抗频选互补码的CDMA上行通信系统中无多用户干扰。针对如何提高互补码的最大可支持用户个数进行研究,提出了偶位移互补码及其传输方案。相比于具有理想相关特性的互补码,偶位移互补码的最大可支持用户个数扩大一倍。首先阐明偶位移互补码的思想来源,并给出偶位移互补码的概念和相关特性。接下来,提出了偶位移互补码的传输方案,并证明了结合该传输方案,偶位移互补码等价为具有理想相关特性的互补码。最后,提出了一种偶位移互补码——I/Q列式互补码的构造方法,并分别分析了基于I/Q列式互补码的CDMA下行通信系统和上行通信系统的抗多用户干扰性能。仿真结果表明基于I/Q列式互补码的CDMA无线通信系统的误码率性能并不差于基于理想相关互补码的CDMA无线通信系统。
[Abstract]:In a wireless communication system, multiple access technology determines the user how to share spectrum resources system. Due to its excellent properties, is widely used in CDMA second and third generation mobile communication system. In the CDMA wireless communication system, the relevant characteristics of the crucial codes, the complexity of the spreading codes have ideal correlation properties can greatly simplify the system, and can achieve full spectrum efficiency. However, the relevant characteristics of the traditional spreading codes with one-dimensional structure cannot achieve the ideal, the traditional CDMA wireless communication system must rely on complex auxiliary subsystems, such as open loop and closed loop power control, Rake receiver, rate matching, uplink synchronization control etc.. Different from the traditional spreading codes, correlation with two-dimensional structure complementary codes can achieve the ideal, then proposed to construct a code Multi access wireless communication system. The ideal characteristics of complementary codes makes a complementary code based on code division multiple access technology is no longer affected by multipath and multiple access interference effects, so as to get rid of the auxiliary system, various traditional CDMA wireless communication system in the future is so complex, one of the bee nest competitive technology in mobile communication system. In addition, in the special field of national defense and aerospace, ideal correlation properties complementary code also makes complementary code based on CDMA technology has great application value. Although researchers have been verified in the Gauss white noise channel and flat fading channel environment based on complementary codes (CC-CDMA) wireless communication system by multi user interference effect, but because of the two-dimensional structure of complementary codes, frequency selective slow fading channel makes the CC-CDMA wireless communication system is facing a huge challenge. On the other hand, Set size of complementary code determines the maximum number of users of CC-CDMA wireless communication system can support, however, has ideal correlation property complementary code set size is small, the application will limit the CC-CDMA wireless communication system. Therefore, this thesis focuses on the two aspects, focusing on the frequency selective slow fading channel detection algorithm the construction method of anti fading channel frequency selection of complementary codes and transmission system, and the construction method can support more users of complementary codes and transmission system, the research results have important value for the practical application of CC-CDMA wireless communication system. The specific research contents and results are as follows: Research on CC-CDMA wireless communication system with ideal correlation complementary code and traditional correlation receiver. First described two has ideal correlation property of complete complementary complementary code Method of generating code and super complementary code. Then, the channel model and the model of flat fading sub channel transceiver based on the established expression vector sub channel output signal receiver correlation detection before form. Then, the received vector of each sub channel output based on the analysis of the flat fading channel, frequency selective slow fading channels, fast flat the fading channel, the performance of CC-CDMA wireless communication system using the ideal complementary code and traditional correlation receiver and chip synchronization condition. Analysis and simulation results show that will destroy the orthogonality between users of the frequency selective fading channel and time selective fading into multi-user interference. For frequency selective slow fading detection algorithm CC-CDMA a wireless communication system in the channel are studied, respectively, and downlink communication uplink communication is proposed based on the minimum mean square error criterion. Single user detection and multiuser detection algorithm for downlink communication, the receiver structure based on single user detection, proposed sub carrier grade MMSE and user level MMSE single user detection algorithm, compared to the orthogonal recovery of maximal ratio combining and detection algorithm, they are neither noise limits, nor for the uplink interference limited. Communication, multiuser detection receiver structure is proposed based on the combination of MMSE-MUD and Zi Zaibo sub carrier independent MMSE-MUD multi-user detection algorithm. The simulation results verify the single user receiver and MMSE multiuser detection receiver has excellent BER performance. Based on research on complementary code structure frequency selective slow fading channel mutual complement and selection, anti frequency transmission system is proposed. First discusses the characteristics are not affected by the frequency selective fading channel complementary code, proposed by Anti frequency selective complemenbary code method for the construction of Golay can complement each other, and analyzes its characteristics. Secondly, aiming at the downlink communication, the transmitter frequency selective anti complementary codes and receiver structure based on the analysis and simulation results show no multiuser interference CDMA downlink communication system against frequency selective complemenbary code based. For the uplink communication, the transmitter frequency selective anti complementary codes and receiver structure based on the analysis and the simulation results also show that no multiuser interference in CDMA uplink communication system anti frequency selective complemenbary code. Based on how to improve the complementary codes can support the number of users of the mutual complement and even shift transmission compared to the scheme. With ideal correlation property of complementary codes, the maximum displacement even complemenbary code can support the number of users doubled. Firstly I displacement complemenbary code ideological source, and give my shift The concept of complementary codes and related characteristics. Then, proposed transmission scheme of double displacement complemenbary code, and it is proved that the combination of the transmission scheme, even equivalent to the mutual complement displacement has ideal correlation property of complementary codes. Finally, this paper proposes a method to construct a mutual complement -- double displacement I/Q column type complementary codes, respectively. Analysis of anti interference performance of CDMA downlink multi-user communication system I/Q column complementary codes and uplink communication system. Based on the simulation results show that the BER performance of CDMA wireless communication system I/Q complementary codes based on CDMA is not bad in a wireless communication system based on ideal cross-correlation complement.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN929.533

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