AI 中文总结
该研究提出动态频率-位置-流体天线（D-FPFA）架构，通过两阶段频率分配、波束分裂复用及粒子群优化算法优化，显著提升太赫兹系统总速率与能效。
AI 中文摘要
为支持太赫兹（THz）通信中的超密集连接，本文提出动态频率-位置-流体天线（D-FPFA）架构。可调谐频率的本地振荡器（LO）被集成到射频链中，以接入不同子带，从而扩展系统总带宽并提供频域分集。为利用空间分集，基站采用可移动子阵列，每个用户配备可移动天线。我们首先开发一种两阶段感知波束分裂的频率分配策略：第一阶段，根据信道相关系数将用户划分为不相交子带以减轻干扰；第二阶段，研究平面阵列的宽带近场波束分裂效应，揭示像散现象——非中心子载波的波束无法在单个空间点完美重新聚焦。随后，我们建立波束分裂复用策略，将用户分组任务建模为最小支配集问题。为最大化总速率，我们引入开关网络及基于距离的天线选择策略以考虑近场信道增益变化，再采用基于粒子群优化的算法联合优化天线位置与预编码器。数值结果表明，所提D-FPFA的总速率约为传统基于移相器（PS）的子阵列阵列（AoSA）架构的2.3倍；其总速率达到基于TTD的对应架构的95%，同时能效（EE）约为后者的2.8倍。此外，D-FPFA的全连接变体即FPFA，在所有考虑的架构中实现最高能效。
英文摘要
To support ultra-dense connectivity in terahertz (THz) communications, this paper proposes a dynamic frequency-position-fluid antenna (D-FPFA) architecture. Frequency-tunable local oscillators (LOs) are integrated into the RF chains to access different sub-bands, thereby expanding the total bandwidth of the system and providing frequency-domain diversity. To exploit spatial diversity, the base station employs movable subarrays, and each user is equipped with a movable antenna. We first develop a two-phase beam-split-aware frequency allocation strategy. In the first phase, we divide users into disjoint sub-bands according to their channel correlation coefficients to mitigate the interference. In the second phase, we investigate the wideband near-field beam-split effect for planar arrays and reveal an astigmatism phenomenon, in which the beam at a non-central subcarrier cannot be perfectly refocused at a single spatial point. Then, we establish a beam split multiplexing strategy, where we formulate the user grouping task as a minimum dominating set problem. To maximize the sum rate, we introduce a switch network along with a distance-based antenna selection strategy to account for the near-field channel gain variations, followed by a particle swarm optimization-based algorithm that jointly optimizes the antenna positions and precoders. Numerical results show that, the proposed D-FPFA achieves approximately 2.3 times the sum rate of a conventional phase-shifter (PS)-based array-of-subarrays (AoSA) architecture. It also attains 95% of the sum rate of its TTD counterpart while providing approximately 2.8 times its energy efficiency (EE). Moreover, the fully connected variant of D-FPFA, i.e., FPFA, achieves the highest EE among all considered architectures.
