UC Irvine

In this dissertation, the analysis and design of asynchronous non-orthogonal multiple access (ANOMA) are presented and the advantages of ANOMA over the conventional nonorthogonal multiple access (NOMA) are detailed. The gain of ANOMA over NOMA, which is called "sampling diversity", results from intentionally introducing the symbol asynchrony at the transmitter and applying the oversampling technique at the receiver. In this dissertation, first, the conventional NOMA is introduced, including the superposition coding and the successive interference cancellation (SIC), and the trellis code is designed and optimized specifically for NOMA systems with the aid of the tensor product of trellises. Second, we analyze the performance of an uplink ANOMA system and the effects of timing errors on the system performance. It is revealed that ANOMA achieves a higher sum throughput compared with NOMA and the synchronization timing error causes a more severe performance loss compared with the coordination timing error. Third, a downlink cooperative ANOMA system with user relaying is studied, including the throughput performance and the power consumption. It is demonstrated that ANOMA is more power efficient compared with NOMA. Finally, we further investigate the impact of imperfect channel state information (CSI) on ANOMA systems. It is shown that under the same channel estimation error, the users in ANOMA systems achieve a lower outage probability compared with those in NOMA systems. Furthermore, the limited feedback scheme for the downlink ANOMA systems is proposed and optimized. It is manifested that ANOMA can achieve the same or even higher average max-min rate as NOMA with a lower feedback rate.