【作者】 蒋海平；

【导师】 邓平；

【作者基本信息】 西南交通大学 ， 通信与信息系统， 2008， 硕士

【摘要】 随着无线通信、互联网和多媒体技术的快速发展,新一代移动通信模式正朝着丰富、快速、灵活、高效等方向发展。正交频分复用和多天线收发技术被公认为新一代无线通信网络主流的信息传输处理技术,这使得无线资源管理面临许多新的问题。为此,本论文研究基于OFDMA和MIMO技术的新一代无线通信网络中无线资源管理机制。首先,本文在新一代无线通信网络架构和通信业务类型的基础上,分析了新一代无线通信网络无线资源管理新的研究方向和研究现状,包括:基于MIMO/OFDM的时域、频域和空域等维度的联合资源管理技术、具有QoS保障的动态自适应无线信道资源分配技术、融合休眠与分组调度控制的终端节能技术等。其次,针对OFDMA技术的特点,OFDMA系统可以根据用户的无线信道质量状况和QoS需求,动态地分配给用户子载波,本文提出了一种保证用户QoS的子载波分配算法。算法在没有增加计算复杂度的情况下,提高了系统吞吐量并保证了用户之间的公平性。再次,由于现有的MIMO系统中用户具有不同的运动速度,因此用户业务可分为高速用户业务和低速用户业务。对于高速用户,由于其信道质量状况变化很快,如果仍采用目前的基于信道信息反馈的资源分配方法,信道质量信息不能实时反映信道质量状况,将无法保证系统的性能。同时,如果无线资源分配基于完全信道信息反馈,将会增加系统的信息反馈量,造成较大的信息冗余。因此,本文设计了MIMO系统中的下行链路无线资源分配系统,并提出了相应的下行链路无线资源分配机制,该机制可以使得发送端区分对待低速用户和高速用户业务,并分别采用不同的无线资源调度方法。然后,针对MIMO空间复用系统,接收端一般需要接收信道状态信息并反馈回发送端,在发送端获取存在信道状态信息估计误差的情况下,信道状态信息的估计误差将会对发送端功率分配造成影响。因此,本文引入了信道信息估计误差因子,采用更加精确的系统模型,以最大化系统数据传输速率的目标,对系统功率分配进行了建模,并提出了贪婪的功率分配算法。该算法同时保证了每个数据流的BER需求。为了满足多用户在多天线系统中各种不同的用户QoS需求,同时尽可能的降低多用户间的干扰,在多天线系统中需要有效的多用户传输机制。但是,现有技术大多是从单一的物理层或媒质接入控制等层进行考虑,无法同时满足各用户的QoS需求和系统整体传输容量最大。本文采用跨层设计的思想,联合考虑物理层和媒体接入控制MAC层,提出了一种多用户多天线传输的方法,实现多用户多天线跨层优化传输。最后,进行了全文总结,并对下一步工作展望。更多还原

【Abstract】 With the rapid development of wireless communication, internet and multimedia, the modes of new generation mobile communication networks become diverse, high-speed, flexible and high efficient. Orthogonal frequency division multiplexing (OFDM) and multiple-input multiple-output (MIMO) have been acknowledged as two major information transmission and processing techniques for next generation wireless communication networks, thus there are many problems to be faced for radio resource management. Therefore, the schemes of radio resource management in new generation wireless communication networks based on MIMO/OFDMA are researched in this dissertation.Firstly, according to the architectures and communication services of new generation wireless communication networks, some new research areas and status of radio resource management in new generation wireless communication are analyzed, including: integrated radio resource management based on time, frequency, space dimensions of MEVIO/OFDM, QoS aware based adaptive channel allocation techniques and energy efficient integrated scheduling technique.Secondly, for the characteristic of OFDMA technique, the OFDMA based systems can allocate dynamically subcamers to users in terms of the channel quality and QoS requirement. A novel algorithm is proposed which can guarantee users’ QoS requirements. Simulation results show that the algorithm improve the system’s throughput and guarantees the fairness among users while not increasing its computation complexity.Thirdly, users’ services can be divided into high speed and low speed services group in terms of the velocity of users. Since their channel states vary quickly for high speed users, the channel state information which is fed back by the receiver can not show the real-time condition so that can not guarantee system’s performance. At the same time, if radio resource allocation is fully based on channel state information, these increase the needed number of feedback bits and lead to feedback overhead. Therefore, downlink radio resource allocation systems based on MIMO and related schemes are designed. The radio resource allocation mechanism allocates distinctly radio resource to high speed group and low speed group and adopts the corresponding methods respectively.Fourth, for MIMO spatial multiplexing systems, channel state information should be estimated at the receiver and fed back to the transmitter. Channel estimation error usually exists in practical systems, which leads to the degradation of the power allocation at the transmitter. In this dissertation, the power allocation problem is presented by adopting the factor of channel estimation, and a greedy power allocation algorithm is proposed to maximize the system data rate. It is showed that the algorithm can guarantee each data stream bit error rate requirement.In order to meet users’ QoS requirements in multiuser MIMO systems and reduce the multiuser interference, the efficient multiuser transmission schemes are needed. However, most of the current techniques respectively consider the physical or media access control layer, which can not guarantee QoS requirement and maximize the systems throughput. A cross-layer transmission method for multiuser MIMO systems is proposed by considering jointly the physical and MAC layer, which optimizes the system performance.At last, the conclusion is made and future work is proposed.更多还原