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arXiv 2408.15435eess.SP
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全局最优的可移动天线增强多用户通信:离散天线定位、运动功耗与非理想信道状态信息

Globally Optimal Movable Antenna-Enhanced multiuser Communication: Discrete Antenna Positioning, Motion Power Consumption, and Imperfect CSI

Yifei Wu, Dongfang Xu, Derrick Wing Kwan Ng, Wolfgang Gerstacker, Robert Schober

AI总结:

本文研究可移动天线多用户通信中离散天线定位、运动功耗及非理想CSI下的鲁棒资源分配问题,提出基于分支定界和逐次凸近似的算法,在保证用户SINR的同时最小化基站总功耗并验证其最优性与实用性。

摘要:

可移动天线(MAs)代表了一种有前景的范式,通过在指定发射区域内动态调整天线单元的位置,来增强传统多天线系统的空间自由度。特别是,通过采用机电式MA驱动器,可以调整MA单元的位置以塑造有利的空间相关性,从而提升系统性能。尽管已有初步研究探索了MA系统的波束成形设计,但MA单元功耗的复杂性以及其精确定位问题尚未被充分理解。此外,文献中采用的完美信道状态信息(CSI)假设由于获取完美CSI需要巨大的导频开销和大量时间而不切实际。为应对这些挑战,我们将MA单元的运动建模为离散步骤,并将相关功耗量化为这些移动的函数。进一步地,通过利用MA信道模型的特性,我们引入了一种专为MA系统定制的新型CSI误差模型,以促进鲁棒资源分配设计。特别地,我们优化基站(BS)处的波束成形和MA位置,以最小化基站总功耗,包括辐射功耗和MA运动功耗,同时保证每个用户所需的最小信干噪比(SINR)。为此,我们开发了利用分支定界(BnB)方法的新算法,以获得完美和非完美CSI下的最优解。此外,为支持实际部署,我们通过利用逐次凸近似(SCA)提出了具有收敛保证的低复杂度算法。数值结果验证了所提出的基于BnB算法的全局最优性。进一步地,我们揭示所提出的两种基于SCA的算法在几次迭代内即可接近最优性能,从而突显了它们的实际优势。

英文摘要:

Movable antennas (MAs) represent a promising paradigm to enhance the spatial degrees of freedom of conventional multi-antenna systems by dynamically adapting the positions of antenna elements within a designated transmit area. In particular, by employing electro-mechanical MA drivers, the positions of the MA elements can be adjusted to shape a favorable spatial correlation for improving system performance. Although preliminary research has explored beamforming designs for MA systems, the intricacies of the power consumption and the precise positioning of MA elements are not well understood. Moreover, the assumption of perfect CSI adopted in the literature is impractical due to the significant pilot overhead and the extensive time to acquire perfect CSI. To address these challenges, we model the motion of MA elements through discrete steps and quantify the associated power consumption as a function of these movements. Furthermore, by leveraging the properties of the MA channel model, we introduce a novel CSI error model tailored for MA systems that facilitates robust resource allocation design. In particular, we optimize the beamforming and the MA positions at the BS to minimize the total BS power consumption, encompassing both radiated and MA motion power while guaranteeing a minimum required SINR for each user. To this end, novel algorithms exploiting the branch and bound (BnB) method are developed to obtain the optimal solution for perfect and imperfect CSI. Moreover, to support practical implementation, we propose low-complexity algorithms with guaranteed convergence by leveraging successive convex approximation (SCA). Our numerical results validate the optimality of the proposed BnB-based algorithms. Furthermore, we unveil that both proposed SCA-based algorithms approach the optimal performance within a few iterations, thus highlighting their practical advantages.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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