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针对近场宽带可重构智能表面（Reconfigurable Intelligent Surface, RIS）辅助多用户多输入单输出正交频分多址（Multiple-Input Single-Output Orthogonal Frequency Division Multiple Access, MISO-OFDMA）系统中存在的增益不足、能耗较大以及频谱资源利用不充分的问题，提出一种基于菲涅尔区的RIS辅助OFDMA系统能量效率优化方法。根据基站-RIS-用户传播路径差和RIS阵面内极角分别划分菲涅尔子区和角扇区，由菲涅尔子区与角扇区交集内的反射单元组成候选反射块。在满足用户最低速率等约束的条件下，建立联合优化候选反射块开关状态、候选反射块-用户关联状态与子载波分配的系统能量效率最大化问题。针对该优化问题，设计基于Dinkelbach变换的迭代算法，在多起点内层搜索中联合执行用户最低速率约束优先的动态子载波分配、整体可行性恢复、候选反射块归属调整和候选反射块增删，并通过候选反射块一换一交换进一步细化，获得满足约束的高能量效率可行解。仿真结果表明，与开关式相邻单元分组激活、全激活和随机候选反射块激活方法相比，所提方法能够获得更高能量效率，验证了基于菲涅尔区的候选反射块激活与联合资源分配机制的有效性。
Abstract：To address the insufficient gain, high power consumption, and inefficient spectrum utilization in near-field wideband Reconfigurable Intelligent Surface(RIS)-assisted multiuser Multiple-Input Single-Output Orthogonal Frequency Division Multiple Access(MISO-OFDMA) systems, an energy-efficiency optimization method based on Fresnel zones is proposed for RIS-assisted OFDMA systems. The RIS aperture is partitioned into Fresnel subzones according to the base station–RIS–user propagation path-length differences and into angular sectors according to the in-plane polar angles. The reflecting elements located at the intersections of the resulting subzones and sectors are grouped into candidate reflecting blocks. Subject to the minimum user-rate and resource-allocation constraints, a system energy-efficiency maximization problem is formulated by jointly optimizing the on/off states of the candidate reflecting blocks, their associations with users, and subcarrier allocation. An iterative algorithm based on the Dinkelbach transformation is developed to address this problem. Within the multistart inner search, the algorithm jointly performs dynamic subcarrier allocation that prioritizes satisfaction of the minimum user-rate constraints, overall feasibility restoration, candidate-block–user association adjustment, and candidate-block addition and deletion. The solution is further refined through one-for-one candidate-block exchanges, thereby yielding a feasible solution that satisfies all constraints and attains high energy efficiency. Simulation results demonstrate that, compared with schemes based on switchable activation of adjacent-element groups, activation of all elements, and random activation of candidate reflecting blocks, the proposed method achieves higher energy efficiency. These results validate the effectiveness of the proposed mechanism for Fresnel-zone-based candidate reflecting-block activation and joint resource allocation.
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基本信息:
中图分类号:TN929.5
引用信息:
[1]邢浩哲,虞贵财.基于菲涅尔区的RIS辅助OFDMA系统能效优化[J].无线电通信技术().
基金信息:
国家自然科学基金（62261056）; 青海民族大学理工类科学研究重点项目（2024XJZD01）
2026-10-10
2026-10-10
2026-10-10