LTE上行信道估计和均衡技术的研究及DSP实现

发布时间：2018-03-06 11:01

本文选题：LTE　切入点：信道估计　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：在由3GPP推进的通用移动通信系统(Universal Mobile Telecom System,UMTS)的长期演进(Long Term Evolution,LTE)项目中,信号在经过无线信道传输时会受到多径衰落、多普勒频移和噪声干扰等影响。因此接收机在接收到信号后,需要先对其传输的无线信道特性进行预估,即信道估计。然后再根据其信道特性消除无线信道对传输信号的影响,即信道均衡。本文研究了适合于LTE上行的信道估计算法和信道均衡算法,并通过matlab仿真和DSP实现来验证其性能和效率。同时针对于所研究的判决反馈式均衡算法的误差传播现象提出了两种改进算法。并对改进算法的性能和效率进行了仿真和DSP可行性验证。对于LTE上行信道估计,本文运用了一种共轭相乘的算法。该算法很好的利用了LTE参考信号中ZC序列的自相关性,通过共轭相乘和窗形滤波便可完成信道估计工作。由此避免了其它估计算法中所要运用的除法和求逆等带来的较大运算量。同时经过仿真和实现的验证,其性能仍然能达到系统要求。对于LTE上行信道均衡,本文首先分析了简单的线性均衡算法,之后在此基础上对能进一步消除码间干扰和噪声的判决反馈均衡器进行了深入研究。并通过仿真和实现验证了其性能和效率。然后对判决反馈均衡器在具有深衰落极点的信道下可能会出现误差传播的现象进行了分析。并在此基础上提出了两种改进算法:一种基于串行时域噪声预测的判决反馈均衡器,和一种引入了双判决结构的判决反馈均衡器。最后对两种改进算法进行matlab仿真,验证了其对误差传播的有效抑制性,同时将两种算法在DSP进行实现以测试其可行性。
[Abstract]:In the long term evolution long Term Evolution (LTE) project of Universal Mobile Telecom system (UMTS), a general mobile communication system promoted by 3GPP, the signal is affected by multipath fading, Doppler frequency shift and noise interference when transmitted through the wireless channel. It is necessary to estimate the wireless channel characteristics of its transmission, that is, channel estimation, and then eliminate the influence of the wireless channel on the transmitted signal according to its channel characteristics. In this paper, the channel estimation algorithm and channel equalization algorithm suitable for LTE uplink are studied. The performance and efficiency of the improved algorithm are verified by matlab simulation and DSP implementation. Two improved algorithms are proposed to deal with the error propagation phenomenon of the decision feedback equalization algorithm, and the performance and efficiency of the improved algorithm are discussed. Simulation and DSP feasibility verification. For LTE uplink channel estimation, In this paper, a conjugate multiplication algorithm is used, which makes good use of the autocorrelation of ZC sequence in LTE reference signal. The work of channel estimation can be accomplished by conjugate multiplication and windowed filtering, thus avoiding the large computation of division and inverse, which will be used in other estimation algorithms. At the same time, it is verified by simulation and implementation. Its performance can still meet the system requirements. For LTE uplink channel equalization, this paper first analyzes a simple linear equalization algorithm. On the basis of this, the decision feedback equalizer which can further eliminate inter-symbol interference and noise is studied in depth. The performance and efficiency of the equalizer are verified by simulation and implementation. Then, the decision feedback equalizer with deep fading is studied. In this paper, the phenomenon of error propagation in the channel is analyzed. Based on this, two improved algorithms are proposed: a decision feedback equalizer based on serial time-domain noise prediction. And a decision feedback equalizer with dual decision structure is introduced. Finally, two improved algorithms are simulated by matlab to verify their effectiveness in restraining error propagation. At the same time, the two algorithms are implemented in DSP to test their feasibility.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.5

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