| Popis: |
Non-orthogonal multiple access (NOMA) has emerged as a promising solution for enabling massive connectivity in future wireless networks. A great deal of research has extensively considered the implementation of the NOMA with other technologies such as multi-antenna and cooperative communications. Most of the previous studies focused on investigating the downlink NOMA networks, while the uplink papers received relatively less attention. Besides, the majority of the current studies on uplink NOMA schemes have neglected practical limitations. Motivated by this, we investigate the uplink single-input multiple-output cooperative NOMA (SIMO-CNOMA) performance in the presence of hardware impairment (HWI), imperfect channel state information (ipCSI), and imperfect successive interference cancellation (ipSIC). We expand the scope of the proposed system to encompass multiple relay schemes, within which the selection relay technique is executed. We derive the outage probability (OP) and the system throughput of the considered system over the Rayleigh fading channels. In this respect, we provide performance analysis for different combinations of relays and antennas. The OP and system throughput analytical expressions are validated through computer simulations. In addition, the effects of HWI, ipCSI, and ipSIC on the performance of the uplink SIMO-CNOMA are discussed. The results show that the system’s performance can be improved with an increase in the relays and antenna numbers. Also, there is an error floor at the high signal-to-noise ratio (SNR) in ideal conditions (i.e., in the absence of HWI, ipCSI, and ipSIC), and the error floor is increased in non-ideal conditions (i.e., in the presence of HWI, ipCSI, and ipSIC). The arbitrary number of users in the presence of non-ideal conditions increases the error and reduces the system’s performance. Finally, although the performance gains obtained through the use of multiple antennas and relays, the adverse effects of HWI, ipCSI, and ipSIC on system performance cannot be avoided. |
