全波校准的逐单元RIS建模及跨孔径系数迁移用于多径信道预测
Full-Wave-Calibrated Element-Wise RIS Modeling With Cross-Aperture Coefficient Transfer for Multipath Channel Prediction
- Institute of Science and Technology, Niigata University（新潟大学科学技术研究院）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
针对实际RIS寄生散射导致多径预测偏差的问题，提出全波校准逐单元模型，通过三阶布拉格基函数及跨孔径系数迁移，在154 GHz下高效实现高精度多径信道预测。
AI中文摘要：
实际的可重构智能表面（RIS）可能表现出确定性的寄生散射，这种散射无法被理想的逐单元模型所捕获。因此，此类模型可能高估预期RIS辅助路径的增益，并使多径预测产生偏差。本文利用三个布拉格阶基函数开发了一种全波校准的逐单元模型，以表示预期及主要的寄生散射分量。环境多径通过射线追踪（RT）识别RIS到Rx的反射序列，并利用镜像理论将其展开为路径相关的镜像点，从而纳入模型中。这使得直接和反射的RIS辅助路径可以使用相同的逐单元核进行评估，并与Tx到Rx的旁路路径相干合并。为了在规定的聚焦配置下减少大型RIS的全波校准负担，仅将三个布拉格阶系数从25×25的校准孔径迁移，而目标孔径的基函数和几何则重新计算。在154 GHz下，迁移的系数使50×50和100×100的RIS的预期阶误差保持在0.8 dB以内，同时将规定配置的全波校准时间从直接100×100校准的7.56小时减少到1.08小时。对于50×50 RIS的多径验证，使用相同迁移系数的校准模型在四种PEC反射器配置下将标称Rx增益误差保持在0.88 dB以内，而未校准的通用模型为1.75至5.51 dB，并在缩放的室内环境中将误差从6.49 dB降低到0.23 dB。
英文摘要：
Practical reconfigurable intelligent surfaces (RISs) can exhibit deterministic parasitic scattering that is not captured by idealized element-wise models. As a result, such models may overestimate the gain of the intended RIS-assisted path and bias multipath prediction. This paper develops a full-wave-calibrated element-wise model using three Bragg-order basis functions to represent the intended and dominant parasitic scattering components. Environmental multipath is incorporated by identifying RIS--Rx reflection sequences with ray tracing (RT) and unfolding them by image theory into path-dependent image points. This allows direct and reflected RIS-assisted paths to be evaluated using the same per-element kernel and coherently combined with Tx--Rx bypass paths. To reduce the full-wave calibration burden for large RISs under a prescribed focusing configuration, only the three Bragg-order coefficients are transferred from a 25-by-25 calibration aperture, while the target-aperture basis functions and geometry are recomputed. At 154 GHz, the transferred coefficients keep the intended-order errors within 0.8 dB for the 50-by-50 and 100-by-100 RISs, while reducing the full-wave calibration time for the prescribed configuration from 7.56 to 1.08 h relative to direct 100-by-100 calibration. For multipath validation with the 50-by-50 RIS, the calibrated model using the same transferred coefficients keeps the nominal-Rx gain error within 0.88 dB across four PEC reflector configurations, compared with 1.75--5.51 dB for the uncalibrated general model, and reduces the error from 6.49 to 0.23 dB in the scaled indoor environment.
