【作者】 刘长美；

【导师】 林家儒；

【作者基本信息】 北京邮电大学 ， 信号与信息处理， 2013， 硕士

【摘要】 MIMO预编码技术无论对单用户通信系统还是多用户通信系统都具有十分重要的作用,它能通过调整同一用户各个数据流的功率和相位信息使单用户获得最大信道容量,在对多用户系统进行预编码时,通过对多个用户的信道信息进行处理,从而抑制多用户之间的干扰,获得多用户系统的最大传输容量。本文主要讨论了单用户预编码的鲁棒设计和多用户系统基于有限反馈的联合用户调度和预编码算法,并对频谱感知系统中的从用户选择和预编码方法进行了探讨。预编码的设计严重依赖于发端获得的信道信息的准确程度,本文针对造成信道信息不准确的因素进行了信道误差建模,通过对目标函数取期望值代替瞬时值,推导出了鲁棒线性预编码的闭式解。仿真证明,信道误差建模如果能很好的利用信道的时间相关性和信道估计误差的统计均方值等信息,鲁棒预编码性能要比非鲁棒的预编码性能高1-2dB。多用户传输系统中基于有限反馈的多用户调度联合预编码技术得到普遍认可。本文分析了两种得到广泛讨论的用户调度方法PU2RC和BCI的优势和不足,提出了一种改进的用户调度算法,在反馈量中增加了少量反馈信息用来表示该用户支持的最大调度用户数目,但和BCI相比,反馈量仍然大大降低,该算法使得用户在反馈量和吞吐量之间获得一个更佳的折中。频谱感知技术允许从用户在不影响主用户正常使用的情况下接入主用户的频谱,以提高频谱的利用率。本文针对此场景,提出了一种基于有限反馈的联合用户调度和预编码算法,该算法与非基于有限反馈的算法相比,计算复杂度低,易于实用,同时不易受非理想信道信息的影响,并仿真分析了码本大小及主用户的服务质量要求对该算法性能的影响。更多还原

【Abstract】 MIMO precoding algorithms play a very important role both in single-user and multi-user communication systems. By adjusting the phase of transmitting signal, the user can achieve maximum channel capacity for a single-user communication system. For multi-user communication system, precoding algorithm can suppress the interference from other users. The paper mainly studies the robust precoding algorithm for single-user system, joint user scheduling and beamforming algorithm for multi-user system, and joint user selection and precoding algorithm in spectrum sensing system.The precoding algorithms highly rely on the accuracy of channel information. By giving a channel error model and using objective function expectations instead of instantaneous value, this paper derives a closed-form of robust scheme. The simulation results demonstrate that if channel error modeling can make best of the channel correlation and covariance of estimation error, robust algorithm can be better than non-robust algorithm for1～2dB.The joint multi-user scheduling and precoding technology for multi-user transmission system is widely recognized. This paper first analysis two algorithms PU2RC and BCI, and then proposes an improved user scheduling scheme. By ensuring the quality of service of each user as well as the maximum channel capacity of the system, the amount of feedback is not high, and the feedback bit is still lower compared to BCI, gaining a benefit both in throughput and feedback bit.Spectrum sensing technology allows secondary user to access the spectrum of primary user and improves the utilization of the spectrum. This paper proposes a joint user scheduling and precoding algorithm based on limited feedback in this system. Compared with SS-BD algorithm which can pre-cancell the primary user’s suffering interference, the proposed algorithm can have a strong robustness. And the factor such as the size of codebook and the QoS of primary user to the proposed algorithm is simulated.更多还原