通信工程文献翻译——摘要：干扰协调的关键是降低TD-LTE系统中的小区间干扰。由于实现复杂度，局部和软频率复用方案是很难适用于TD-LTE系统。解码和转发中继方案，这可能会产生一些额外的干扰，提出了扩大覆盖范围和提高TD-LTE系统的性能。为了减轻继电器相关的干扰，定向继电器的拓扑结构，提出了本文。无线电资源被分离的RS之间的重复使用，以提高频谱效率。该合资干扰协调和方向继电器可以抑制大多数小区间和继电器间的干扰，提高了能力。该信号与干扰加噪声比（SINR）的分布和吞吐量传统的无中继方案及建议方向继电器的情况推导。理论分析和仿真结果表明该建议方案的有效性。

一.引言

由3GPP（第三代合作伙伴计划）推出的LTE（长期演进）系统是基于OFDMA（正交频分复用），多个天线和其他创新的技术，以实现高传输速率和提高的覆盖[1]。在LTE系统可以工作在两种FDD（频分双工）和TDD（时分双工）模式。值得注意的是，TDD模式已经在TD-SCDMA实现。有基于TDD技术2的LTE系统，以及它们在物理层趴在两种类型的帧结构的不同之处：1被称为FDD LTE系统和被命名为类型1，而另一个称为TD-LTE系统，它使用一种特殊的帧结构与TD-SCDMA被对齐并且被命名为类型2。

在LTE系统中的干扰抑制技术可以通过接收器的处理可分为三大类，如干扰消除，干扰随机化通过跳频，并通过征收资源使用的资源划分和权力分配方面的限制干扰协调实现。用于干扰协调，部分频率复用（PFR）[2]和软频率复用（SFR）[3]是2的变化。由于过度X2接口和难度来确定用户设备（UE）的位置的基站（eNB）的之间的复杂信号发送模式时，PFR和SFR计划仍然有巨大的差距，以获得最大干扰避免增益在实践中。

以改善小区边缘用户的服务质量，提高系统的吞吐量，并扩大小区覆盖， decodeand - 转发（DF ）中继站（RS）技术已经在无线蜂窝网络中被使用。在[4]，与固定RS的蜂窝网络的目的是要提供一种良好的频谱效率为位于小区边界内UE ，其中的一些无线资源管理策略，如路径选择，频率复用和中间帧的传输模式匹配的问题区域，进行了讨论。它被证实[5]中，该RS会产生额外的干扰，从而可能会降低对边缘UE的信道质量，相邻小区。以克服在多个小区由于......

Abstract—Interference coordination is the key to reduce intercell interference in a TD-LTE system. Because of implementation complexity, partial and soft frequency reuse schemes are hardly suitable to TD-LTE systems. The decode-and-forward relay scheme, which may generate some additional interference,is presented to extend coverage and improve performance of TD-LTE systems. To mitigate the relay related interference,a directional relay topology is proposed in this paper. The radio resource is reused between the isolated RSs to improve the spectrum efficiency. The joint interference coordination and directional relay can suppress most inter-cell and inter-relay interferences and improve the capacity. The signal to interference plus noise ratio (SINR) distributions and throughput for the traditional non-relay scenario and the proposed directional relay scenario are derived. The analysis and simulation results show the effectiveness of the proposal scheme.

I. INTRODUCTION

The LTE (Long Term Evolution) system launched by the 3GPP (3rd Generation Partnership Project) is based on OFDMA (Orthogonal Frequency Division Multiplexing), multiple antennas and other innovative techniques to achieve a high transmission rate and enhance the coverage [1]. The LTE systems may work at both FDD (Frequency Division Duplex)and TDD (Time Division Duplex) modes. It is noted that TDD mode has already been implemented in TD-SCDMA.

There are two LTE systems based on TDD technique, and their differences in physical layer lie on two types of frame structures: one is called FDD LTE system and is named as Type 1, while the other called TD-LTE system which uses a special frame structure to be aligned with TD-SCDMA and is named as Type 2.

Interference mitigation techniques in LTE systems can be classified into three major categories such as interference cancelation through receiver processing, interference randomization by frequency hopping, and interference coordination achieved by restrictions imposed in resource usage in terms of resource partitioning and power allocation. For the interference coordination, the partial frequency reuse (PFR) [2] and soft frequency reuse (SFR) [3] are two variations. Due to the......