OFDMA系统的频率同步和自适应资源分配技术研究

【作者】 严杰；

【导师】 李式巨；

【作者基本信息】 浙江大学 ， 信息与通信工程， 2006， 硕士

【摘要】 正交频分复用(OFDM)以其频谱效率高,对频率选择性和多径信道抵抗能力好等特点,近年来成为无线通信领域里的研究热点。以OFDM调制为基础的正交频分多址(OFDMA)是新一代的无线接入技术,它将接入和调制有效地结合在了一起,已经成为未来移动通信系统的重要技术之一。本文阐述了OFDMA系统的基本原理。针对子载波交织分配的OFDMA系统上行链路,利用其接收信号周期性的结构,提出一种基于ESPRIT算法的多用户频偏估计解决方案,通过子空间旋转不变的特点准确地估计出各用户的载波频偏。针对OFDMA系统自适应资源分配问题,提出一种具有QoS保证的自适应子载波和功率分配算法。对于实时用户,系统采用子载波和功率交替分配的方式,保证其数据率额定值和目标误码率限制的要求;对于非实时用户,按照数据率比例公平的要求,子载波和功率分配分离进行。通过利用近似线性化的方法,大大减少了计算复杂度。更多还原

【Abstract】 Much research has been devoted to Orthogonal Frequency Division Multiplexing (OFDM) in broadband wireless communication for its high spectral efficiency and ability in mitigating the effects of frequency selective or multipath channel propagation. Built upon OFDM, Orthogonal Frequency Division Multiple Access (OFDMA) is a new wireless access technique. It effectively combines the multiple access method with the modulation process, and has emerged as one of key technologies in future wireless mobile communication system. In this thesis, we present the basic principle of OFDMA system. For the uplink OFDMA system, the interleaved subcarrier allocation strategy results in the received signal a periodic structure. We propose an ESPRIT based algorithm to accurately estimate the multi-user frequency offset via subspace rotational invariance technique. For the OFDMA resource allocation problem, a QoS guaranteed adaptive subcarrier and power allocation algorithm is proposed. We allocate the subcarrier and power jointly in real time users’ allocation process, to fulfill the transmission rate and object bit error rate requirements. Subcarrier and power allocation is performed separately for non-real time users with the proportional rate constraints. By using the linearized method, computational complexity is reduced greatly更多还原