Rate-splitting multiple access (RSMA) has attracted a lot of attention as a general and powerful multiple access scheme. In the uplink, instead of encoding the whole message into one stream, a user can split its message into two parts and encode them into two streams before transmitting a superposition of these two streams. The base station (BS) uses successive interference cancellation (SIC) to decode the streams and reconstruct the original messages. Focusing on the packet transmission reliability, we investigate the features of RSMA in the context of hybrid automatic repeat request (HARQ), a well-established mechanism for enhancing reliability. This work proposes a HARQ scheme for uplink RSMA with different retransmission times for a two-user scenario and introduces a power allocation strategy for the two split streams. The results show that compared with non-orthogonal multiple access (NOMA) and frequency division multiple access (FDMA), RSMA outperforms them in terms of error probability and power consumption. The results show that RSMA with HARQ has the potential to improve the reliability and efficiency of wireless communication systems.

翻译：速率分割多址接入（RSMA）作为一种通用且强大的多址接入方案，已引起广泛关注。在上行链路中，用户无需将整个消息编码为单一数据流，而是可将消息分割为两部分，分别编码为两个数据流，再传输这两个数据流的叠加信号。基站（BS）采用连续干扰消除（SIC）技术对这些数据流进行解码，并重构原始消息。本文聚焦于分组传输可靠性，研究RSMA在混合自动重传请求（HARQ）这一成熟可靠性增强机制下的特性。针对两用户场景下不同重传次数的上行RSMA，本文提出了一种HARQ方案，并引入了一种针对两分割数据流的功率分配策略。结果表明，与采用非正交多址接入（NOMA）和频分多址接入（FDMA）的方案相比，RSMA在误码率和功耗方面均表现更优。研究证明，结合HARQ的RSMA具有提升无线通信系统可靠性与效率的潜力。