In this paper, we propose a novel joint caching and non-orthogonal multipleaccess (NOMA) scheme to facilitate advanced downlink transmission for nextgeneration cellular networks. In addition to reaping the conventionaladvantages of caching and NOMA transmission, the proposed cache-aided NOMAscheme also exploits cached data for interference cancellation which is notpossible with separate caching and NOMA transmission designs. Furthermore, ascaching can help to reduce the residual interference power, several decodingorders are feasible at the receivers, and these decoding orders can be flexiblyselected for performance optimization. We characterize the achievable rateregion of cache-aided NOMA and investigate its benefits for minimizing the timerequired to complete video file delivery. Our simulation results reveal that,compared to several baseline schemes, the proposed cache-aided NOMA schemesignificantly expands the achievable rate region for downlink transmission,which translates into substantially reduced file delivery times.
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