適用於蜂巢網路新型合作式功率域NOMA情境之研究

Abstract

本論文提出了一種新的非正交多址-合作式放大傳輸中繼（non-orthogonal multiple access-cooperative amplify-and-forward relay；NOMA-CAFR）網路模型，利用同一頻段進行上行和下行傳輸，在設備對設備通信機制下為兩個使用者終端（user terminals；UTs）提供服務，包括強頻分雙工（frequency-division-duplex；FDD）UT和弱UT。在上行鏈路傳輸中，強 FDD UT 轉發來自弱 UT 的資訊信號，並通過功率分配 NOMA 向基地台（base station；BS）傳輸自己的資訊信號。在下行鏈路傳輸中，基地台向強 FDD UT 發送組合資訊信號，然後強 FDD UT 再向弱 UT 轉發組合資訊信號。與傳統的正交多址（orthogonal multiple access；OMA）網路模型相比，該模型可實現更高的系統輸送量和使用者公平性，尤其是在下行鏈路場景中。雖然我們提出的 NOMA-CAFR 網路模型需要額外的鏈路狀態測量，從而導致額外的成本，但它具有顯著的系統性能優勢，使其成為在特定的目標和約束條件下優於 OMA的選擇。

This thesis proposes a new non-orthogonal multiple access-cooperative amplify-and-forward relay (NOMA-CAFR) network model which utilizes the same frequency band for both uplink and downlink transmissions, serving two user terminals (UTs), including the strong frequency-division-duplex (FDD) UT and the weak UT, under the device-to-device communication mechanism. In the uplink transmission, the strong FDD UT relays message signals from the weak UT and transmits its own message signals to the base station (BS) via power-division NOMA. In the downlink transmission, the BS sends combined message signals to the strong FDD UT, and the strong FDD UT then relays combined message signals to the weak UT. This model achieves higher system throughput and user fairness compared to traditional orthogonal multiple access (OMA) network models, particularly in downlink scenarios. Although the proposed NOMA-CAFR network model requires additional link state measurements, resulting in additional costs, it provides significant system performance advantages, making it a superior choice over OMA depending on specific objectives and constraints.