所謂的索引調變（IM）方案，利用傳輸元素（例如，天線、時隙和子載波）的索引來傳遞更多非正式訊息。最近，一種新的IM方案，即廣義正交空間調變（GQSM），已被提出用於激活更多傳輸天線以實現空間調變。此外，QSM與非正交多重接取（NOMA）傳輸方案的組合也被提議用於構建合作車載網絡。受這些杰作的啟發，我們在這項研究中，基於NOMA和GQSM開發了一種新的合作中繼方案。首先，來源端與中繼（即，第二層傳輸）之間的傳輸使用兩個階段進行。在第一階段，兩個來源節點使用NOMA技術同時傳輸信號；而在第二階段，兩個來源節點互相轉發在第一階段接收到的信號，並且也使用NOMA。然後，使用最大概似原則來檢測中繼器的信號。之後，中繼器使用NOMA將他們的訊息與從來源端收到的訊息（即，第一層傳輸）一起上傳到基地台。通過所提出的功率控制方案，所有傳輸實體的等效的端到端信號結果可以在目的地獲得，這已被模擬結果驗證。

The so-called index modulation (IM) scheme utilizes indexes of the transmission elements (e.g., the antennas, time slots and subcarriers) to convey more informal messages. Recently, a new IM scheme, namely the generalized quadrature spatial modulation (GQSM), has been proposed to activiate more transmit antennas for implementing the spatial modulation. Moreover, the combination of QSM and non-orthogonal multiple access (NOMA) transmission scheme was proposed for constructing the cooperative vehicular networks as well. Motivated by these masterpieces, in this study, we develop a novel cooperative relaying scheme based on NOMA and GQSM. Firstly, the transmissions between the source and relay (i.e., namely the tier-2 transmission) are conducted using two phases. In the first phase, two source nodes transmit signals simultaneously using the NOMA technique; whereas in the second phase, the two source nodes forward the received signals in the first phase via NOMA for each other as well. Then, the principle of maximal likely hood is implemented to detect the signals at the relays. Afterwards, the relays upload their messages together with the received messages for the sources using NOMA as well (i.e., the tier-1 transmission). Via the proposed power control scheme, the equivalent end-to-end signal quality for all the transmitting entities can be obtained at the destinations, which has been verified by the simulation results.

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