标题：Non-orthogonal Multiple Access With Cooperative Truncated ARQ and Relay Selection
作者：Yu, Zhiyuan; Zhai, Chao; Ni, Wan; Wang, Desheng
作者机构：[Yu, Zhiyuan; Ni, Wan; Wang, Desheng] Shandong Univ, Sch Journalism & Commun, Jinan 250100, Shandong, Peoples R China.; [Zhai, Chao] Shandong Univ, 更多
通讯作者：Yu, ZY;Yu, Zhiyuan
通讯作者地址：[Yu, ZY]Shandong Univ, Sch Journalism & Commun, Jinan 250100, Shandong, Peoples R China.
关键词：Non-orthogonal multiple access; truncated ARQ; relay selection;; superposition coding; interference cancelation
摘要：In this paper, we propose a cooperative truncated automatic repeat-request (T-ARQ)-based non-orthogonal multiple access schemes with relay selection. There are two phases in our proposed scheme. In the broadcast phase, an access point superimposes the signals of near-user U-1 and far-user U-2 and then broadcasts the composite signal to both users and all the relays. All the terminals will try to decode the signal of U-2 by treating the signal of U-1 as interference. After that, U-1 and relays will further decode the signal of U-1 by canceling the signal of U-2. The relays that can correctly decode the signals of U-2 and U-1 are classified into two decoding sets. In the cooperative T-ARQ phase, the relay from the decoding set with the best channel quality toward U-2 or U-1 is selected to retransmit the signal if necessary. Considering the various decoding statuses of U-1, U-2, and relays, we analyze the system throughput and reveal the impacts of key parameters, such as power allocation factor, transmit power, and target rate. The numerical results show that our proposed scheme can achieve much higher throughput than the T-ARQ-based time-division multiple access schemes.