NOMA With Cache-Aided Maritime D2D Communication Networks

This work proposes a novel scheme of non-orthogonal multiple access (NOMA) combined with cache-enabled maritime device-to-device communication (D2D) networks, which aims to improve the performance of ship users located far from the shore and also reduce the data traffic load at the coastal base station. Taking into account the quality-of-service demands of near ship users along with the poor channel condition of far ship users, a joint beamforming design and NOMA power allocation issue is also considered. In addition, three kinds of decoding order at far ship users are also studied to comprehensively characterize the superiority of the proposed systems. Accordingly, the performance of users is then quantified in terms of outage probability and ergodic capacity, where the respective exact expressions are also evaluated in closed form. Qualitative numerical results corroborates the developed theoretical analysis and reveals that: (1) The adoption of the proposed decoding order scheme to improve the outage performance of far ship users is strongly dominated by the trade-off power setting between the coastal base station and the near ship use; and (2) The ergodic rate achieved by the proposed NOMA with cache-aided maritime full-duplex D2D communication network always outperforms those of benchmark schemes, particularly in saving at least 2.5 dB of transmitting power budget for far ship users and achieving double ergodic capacity for near ship users.