多点多用户协作通信系统同步偏差补偿算法-通信与信息系统专业论文.docxVIP

摘要 摘要 摘 要 随着 IMT-Advanced 技术的演进，新一代宽带无线移动通信领域中出现了一系 列新技术，比如，增强型多输入多输出技术、空时编码技术以及协作多点技术等。 因此，多点多用户协作通信系统越来越成为人们研究的重点。基站将其信号同时 发送给多个终端，而终端将同时同频接收到来自多个协作基站的具有不同同步偏 差（即符号定时偏差和载波频率偏差）的信号，基站端的预补偿策略与终端的后 补偿策略都不能消除这些同步偏差，尽管这在多点单用户系统和单点多用户系统 中是非常有效地。首先，我们证明现存的同步偏差补偿算法均不能完全消除链路 的同步偏差；其次，考虑到系统可以容忍一定同步偏差，多点多用户系统的同步 偏差补偿问题可建模为不等约束下的最优化问题；因此，本文提出了基于“最大 可容忍剩余误差”松弛的同步偏差联合补偿算法；最终，所提算法能够将各链路 的剩余同步偏差控制在可容忍范围内。仿真结果表明，本文所提算法可有效减少 多点多用户系统的同步偏差。 关键词： 多点多用户 协作通信系统 符号定时偏差 载波频率偏差 补偿 Abstract Abstract Abstract With the evolution of the IMT-Advanced, a series of new technologies appear in the next generation broadband wireless mobile communications, for example, the enhanced Multiple Input Multiple Output (MIMO), Space-time Coding, and Coordinated Multiple Points (CoMP). Hence, multipoint-to-multiuser (MtM) cooperative systems have attracted more and more interest from both academia and industry. Since a base station (BS) may transmit its signals simultaneously to multiple user equipments (UEs) and a UE may receive signals with different symbol timing offsets (STOs) and carrier frequency offsets (CFOs) from different coordinated BSs at the given time-slots and subcarriers, it is impossible for BSs to pre-compensate or for UEs to post-compensate the STOs and CFOs as they do in multipoint-to-user or point-to-multiuser systems. Firstly, we convince by demonstrations that the STOs and CFOs cannot be completely eliminated by any existing STO and CFO compensation algorithm. Secondly, since the system can tolerate some level of offset, the STO and CFO compensation problem in MtM cooperative systems is modelled as a constrained optimization. Hence, we propose a STO and CFO joint compensation algorithm associated with relaxed residual STOs and CFOs. Finally, our proposed algorithm is capable of reducing the STOs and CFOs to be lower than the maximum tolerable value. Our simulation results show that the proposed algorithm is capable of reducing the STOs and CFOs effectively in MtM cooperative systems. K