中文摘要：

针对非理想定时同步对协作多点传输的负面影响,提出了多模协作多点传输算法。通过推导协作波束成形模式和联合处理模式在非理想定时同步条件下的平均可达速率,得到模式选择变量和模式选择门限。在多模协作多点传输算法中,用户首先对定时同步误差进行估计,并计算其模式选择变量和模式选择门限。然后用户选择协作多点传输的下行传输模式,并将其选择结果反馈给协作基站。最后,根据各用户的反馈,协作基站以最大化平均可达传输速率为准则,自适应地在协作波束成形模式和联合处理模式之间切换。仿真结果表明多模协作多点传输算法在定时同步误差较小时,采用联合处理模式,以保持空间复用增益,在定时同步误差较大时,采用协作波束成形模式,以避免用户间的额外干扰。因此,在非理想定时同步误差条件下,多模协作多点传输算法比仅采用协作波束成形模式或联合处理模式的传统协作多点传输算法具有更好的性能。

英文摘要：

Against the negative impact of non-ideal timing synchronization on the coordinated multipoint（Co MP） transmission, a multimode algorithm was proposed. According to the average achievable rates of the different Co MP transmission modes under non-ideal timing synchronization condition, such as coordinated beamforming（CB） and joint processing（JP）, the mode selection variable and the mode selection threshold were acquired. In the multimode algorithm for Co MP transmission, user equipments（UE） estimate the timing synchronization errors, calculate the mode election variables and the mode selection thresholds firstly. Afterwards, UEs select the Co MP transmission mode, feedback the selection results to coordinated base stations（BS）. Finally, According to the feedback from UEs, coordinated BSs switch the Co MP transmission mode between CB and JP adaptively to maximize the average achievable rate. Simulation results show that the multimode algorithm adopt JP to maintain spatial multiplexing gain when timing synchronization errors are small, adopt CB to avoid extra interference between UEs when timing synchronization errors are large. Therefore,under non-ideal timing synchronization condition,the proposed multimode algorithm outperforms the traditional algorithms which only adopt CB or JP for Co MP transmission.