In this paper, a multipath component aggregation (MCA) mechanism is introduced for spatial scattering modulation (SSM) to overcome the limitation in conventional SSM that the transmit antenna array steers the beam to a single multipath (MP) component at each instance. In the proposed MCA-SSM system, information bits are divided into two streams. One is mapped to an amplitude-phase-modulation (APM) constellation symbol, and the other is mapped to a beam vector symbol which steers multiple beams to selected strongest MP components via an MCA matrix. In comparison with the conventional SSM system, the proposed MCA-SSM enhances the bit error performance by avoiding both low receiving power due to steering the beam to a single weak MP component and inter-MP interference due to MP components with close values of angle of arrival (AoA) or angle of departure (AoD). For the proposed MCA-SSM, a union upper bound (UUB) on the average bit error probability (ABEP) with any MCA matrix is analytically derived and validated via Monte Carlo simulations. Based on the UUB, the MCA matrix is analytically optimized to minimize the ABEP of the MCA-SSM. Finally, numerical experiments are carried out, which show that the proposed MCA-SSM system remarkably outperforms the state-of-the-art SSM system in terms of ABEP under a typical indoor environment.

翻译：本文针对传统空间散射调制(SSM)中发射天线阵列每次仅将波束对准单个多径(MP)分量的局限性，提出了一种基于多径分量聚合(MCA)机制的SSM方案。在所提出的MCA-SSM系统中，信息比特被分为两路：一路映射为幅度相位调制(APM)星座符号，另一路映射为波束向量符号。该波束向量符号通过MCA矩阵将多个波束对准所选取的最强MP分量。与传统SSM系统相比，所提出的MCA-SSM通过避免因波束对准单个弱MP分量导致的低接收功率，以及因到达角(AoA)或离开角(AoD)相近的MP分量引起的MP间干扰，从而提升了误码性能。针对所提出的MCA-SSM，本文解析推导了任意MCA矩阵下平均误比特概率(ABEP)的联合上界(UUB)，并通过蒙特卡洛仿真进行了验证。基于该UUB，进一步解析优化了MCA矩阵以最小化MCA-SSM的ABEP。最后，数值实验表明，在典型室内环境下，所提出的MCA-SSM系统在ABEP指标上显著优于现有最优的SSM系统。