在可重構智能表面輔助的多用戶多輸入單輸出系統中藉由元件群組放寬設計限制的通道估測法

Abstract

隨著第六代行動通訊技術及其以上的無線通信服務的發展，可重構智能表面是一種能夠增強系統覆蓋範圍和容量的新技術。可重構智能表面由一個能反射傳輸波的超穎介面組成，並且像相移器一樣調整相位以增加通道容量。與中繼技術不同，可重構智能表面是一種幾乎被動的元件，只能調整相位而不能調整振幅，這是其物理限制。本論文考慮通過結合兩個可重構智能表面元素來設計的新方法，從而放寬毫米波多用戶多輸入單輸出系統中通道估計的限制。 其他文獻討論了具有可重構智能表面物理限制的通道估計優化問題。相比之下，我們將兩個可重構智能表面元素作為一組進行設計。因此，我們獲得了一個等效的半維可重構智能表面矩陣，可以調整相位和振幅。在結合兩個可重構智能表面元素時，我們需要將兩個相鄰的可重構智能表面元素盡可能靠近。我們假設這兩個相鄰的可重構智能表面元素具有相同的通道，模擬結果表明，通道估計誤差的性能優於以往的工作。

With the 6G and 6G above wireless communications services, reconfig- urable intelligent surface (RIS) is a novel technique that can enhance the coverage and capacity of the systems. RIS consists of a metasurface that can reflect the transmitted waves and, like a phase shifter, adjust the phase to in- crease channel capacity. Unlike relaying, RIS is a nearly passive element that can only adjust the phase but the amplitude, which is its physical constraint. This thesis considers applying a new way to design RIS by combining two elements of RIS, which relaxes the constraint in channel estimation of the mmWave multi-user MISO system. Other literature discusses channel estimation optimization problem with RIS physical constraint. In comparison, we take two RIS elements as a group to design it. Due to that, we have an equivalent half-dimension RIS matrix that can adjust the phase and amplitude. When combining two RIS elements, we need to place the two nearby RIS elements as close as possible. We assume the two nearby RIS elements have the same channel, and the simulation results show that the performance of channel estimation error is better than the previous work.