In a joint transmission coordinated multipoint (JT-CoMP) system, a shared spectrum is utilized by all neighbor cells. In the downlink, a group of base stations (BSs) coordinately transmit the users’ data to avoid serious interference at the users in the boundary of the cells, thus substantially improving area fairness. However, this comes at the cost of high feedback and backhaul load; In a frequency division duplex system, all users at the cell boundaries have to collect and send feedback of the downlink channel state information (CSI). In centralized JT-CoMP, although with capabilities for perfect coordination, a central coordination node have to send the computed precoding weights and corresponding data to all cells which can overwhelm the backhaul resources. In this paper, we design a JT-CoMP scheme, by which the sum of the mean square error (MSE) at the boundary users is minimized, while feedback and backhaul loads are constrained and the load is balanced between BSs. Our design is based on the singular value decomposition of CSI matrix and optimization of a binary link selection matrix to provide sparse feedback—constrained backhaul link. For comparison, we adopt the previously presented schemes for feedback and backhaul reduction in the physical layer. Extensive numerical evaluations show that the proposed scheme can reduce the MSE with at least \(25\%\), compared to the adopted and existing schemes.

在联合传输协调多点（JT-CoMP）系统中，所有相邻小区都使用共享频谱。在下行链路中，一组基站（BS）协调地发送用户数据，以避免在小区边界处对用户的严重干扰，从而大大提高了区域公平性。然而，这是以高反馈和回程负载为代价的。在频分双工系统中，小区边界处的所有用户都必须收集并发送下行链路信道状态信息（CSI）的反馈。在集中式JT-CoMP中，尽管具有完善的协调能力，但中央协调节点必须将计算出的预编码权重和相应的数据发送到所有可能使回程资源不堪重负的小区。在本文中，我们设计了一个JT-CoMP方案，通过这种方法，边界用户处的均方误差（MSE）之和被最小化，同时反馈和回程负载受到限制，并且各基站之间的负载得到平衡。我们的设计基于CSI矩阵的奇异值分解和二进制链路选择矩阵的优化，以提供稀疏的反馈（受约束的回程链路）。为了进行比较，我们采用先前提出的方案来减少物理层中的反馈和回程。大量的数值评估表明，所提出的方案至少可以降低MSE。我们的设计基于CSI矩阵的奇异值分解和二进制链路选择矩阵的优化，以提供稀疏的反馈（受约束的回程链路）。为了进行比较，我们采用先前提出的方案来减少物理层中的反馈和回程。大量的数值评估表明，所提出的方案至少可以降低MSE。我们的设计基于CSI矩阵的奇异值分解和二进制链路选择矩阵的优化，以提供稀疏的反馈（受约束的回程链路）。为了进行比较，我们采用先前提出的方案来减少物理层中的反馈和回程。大量的数值评估表明，所提出的方案至少可以降低MSE。\（25 \％\），与已采用和现有的方案相比。