LTE上行链路干扰测量和信干噪比预测

发布时间：2018-06-02 12:35

本文选题：时分双工 + 探测参考信号　；参考：《西安电子科技大学》2015年硕士论文

【摘要】：LTE系统中通过链路自适应可以有效的提高数据速率和频谱效率,在上行链路数据传输中作为提升吞吐量的手段,该项技术尤为重要。自适应技术中有两个关键研究点:测量和预测。目的是为了随信道、干扰等环境的变化及时调整数据发送设定的参数,实现频谱利用率和误块率之间的最佳平衡。本文针对直接与最终反馈给用户的调制编码方式相关联的信干噪比入手,探讨了时分双工上行链路中干扰测量和信干噪比预测的问题,并给出了理论阐述和计算机仿真分析对比。首先,本文给出了LTE协议中关于时分双工帧结构配置和探测参考信号相关内容,为后文研究提供了参考标准。探测参考信号分为周期和非周期探测,本文主要采用周期探测。在小区建模使用华为软频率复用方案,降低相邻小区边缘用户间的同频干扰。对于探测参考信号的传输,灵活的采用时分复用、频分复用和码分复用相结合的方式,形成了一种特定帧结构下的干扰测量方案,在较短的时间内获得干扰信息并可以进行及时的更新。然后在基于探测参考信号的信道估计常用算法中选择一种性能较好的方法,即循环移位时域信道估计法,因其对于多用户敏感性较共轭相消信道估计法低。再将该方法结合MMSE信道估计使用,构成一种在全频带下保证估计性能的算法,归一化的MSE达到了0.1,能够有效的得到所需干扰功率信息,测量出较为准确的信干噪比。虽然反馈调制编码方式时根据的是最近的信干噪比信息,但是在传输过程中会有一定的时延。在时延的时间段中,信道和干扰传输背景环境均发生了变化,并不能准确的反映用户下一时刻发送数据时应当采用的调制阶数和码率,所以需要对信干噪比进行预测。预测方法主要分为线性预测方法和非线性预测方法,非线性预测方法复杂度高,需要调整的参数更多,更偏向于实际经验来选取参数。线性方法简单有效,但对于非线性的数据抖动处理并不一定如非线性方法优越。最后,在搭建的系统模型下进行了各类预测方法的仿真,实现吞吐量性能提升。
[Abstract]:The data rate and spectral efficiency can be improved effectively by link adaptation in LTE system. This technique is especially important in uplink data transmission as a means to enhance throughput. There are two key research points in adaptive technology: measurement and prediction. The aim of this paper is to adjust the parameters of data transmission and achieve the best balance between spectrum efficiency and block error rate with the change of channel, interference and other environments. In this paper, the problem of interference measurement and signal-to-noise ratio prediction in time division duplex uplink is discussed. The theoretical explanation and computer simulation analysis are also given. First of all, this paper gives the related contents of the LTE protocol about the time division duplex frame configuration and the detection reference signal, which provides the reference standard for the later research. The reference signal is divided into periodic detection and aperiodic detection. Huawei soft frequency reuse scheme is used in cell modeling to reduce the same frequency interference between adjacent cell edge users. For the transmission of probe reference signal, the method of time division multiplexing, frequency division multiplexing and code division multiplexing is used flexibly to form an interference measurement scheme under a specific frame structure. Access to interference information in a short time and can be updated in a timely manner. Then, one of the common channel estimation algorithms based on probe reference signal is the cyclic shift time-domain channel estimation method, which is less sensitive to multi-user than conjugate cancellation channel estimation method. Then the method is combined with MMSE channel estimation to form an algorithm to ensure the estimation performance in full frequency band. The normalized MSE reaches 0.1, which can effectively obtain the required interference power information and measure the more accurate signal-to-interference noise ratio. Although the feedback modulation coding method is based on the latest signal-to-noise ratio information, there will be a certain delay in the transmission process. In the time delay, both the channel and the interference transmission background environment have changed, which can not accurately reflect the modulation order and the bit rate that the user should adopt when transmitting data at the next time, so it is necessary to predict the signal-to-noise ratio. The prediction method is mainly divided into linear prediction method and nonlinear prediction method. The nonlinear prediction method has a high complexity, more parameters need to be adjusted, and it is more inclined to choose the parameters from practical experience. The linear method is simple and effective, but the nonlinear data jitter processing is not always superior to the nonlinear method. Finally, various prediction methods are simulated under the system model to improve throughput performance.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN929.5

【参考文献】