Faster-than-Nyquist (FTN) signaling aided non-orthogonal multiple access (NOMA) is conceived and its achievable rate is quantified in the presence of random link delays of the different users. We reveal that exploiting the link delays may potentially lead to a signal-to-interference-plus-noise ratio (SINR) gain, while transmitting the data symbols at FTN rates has the potential of increasing the degree-of-freedom (DoF). We then unveil the fundamental trade-off between the SINR and DoF. In particular, at a sufficiently high symbol rate, the SINR gain vanishes while the DoF gain achieves its maximum, where the achievable rate is almost $(1+\beta)$ times higher than that of the conventional synchronous NOMA transmission in the high signal-to-noise ratio (SNR) regime, with $\beta$ being the roll-off factor of the signaling pulse. Our simulation results verify our analysis and demonstrate considerable rate improvements over the conventional power-domain NOMA scheme.

翻译：我们发现,利用连接延迟可能导致信号对干涉加噪音比率增益,同时以FTN率传输数据符号有可能提高自由度。然后,我们公布SINR和DoF之间的基本权衡。特别是,在足够高的符号率下,SINR增益,而DoF增益则达到最大值,在高信号对噪音比率制度中,可实现率几乎比常规同步NOMA传输率高1美元(1 ⁇ 贝塔)倍,而美元是信号脉冲的滚动系数。我们的模拟结果证实了我们的分析,并表明常规的NOMA计划取得了相当大的速率改进。