dc.description.abstract |
Non-Orthogonal Multiple Access (NOMA) and massive Multiple Input Multiple
Output (mMIMO) have been considered or addressed as a promising candidate
for the forthcoming generation networks speci cally fth generation (5G) networks
and beyond 5G. In this thesis, we have discussed and analyzed the performance of
downlink NOMA for massive MIMO Systems in contrast to conventional MIMO
systems. Furthermore, we have also explored the performance gains of MIMO
NOMA compared to its traditional MIMO OMA counterpart. Moreover, we considered
the performance gains of downlink NOMA over conventional OMA schemes
particularly OFDMA systems. Since the early contributions of this area mainly
focused on the scenario of Single Input Single Output (SISO) and conventional
multi-user MIMO systems, it is of particular interest to conduct the performance
analysis of NOMA for massive MIMO systems by comparison with conventional
MIMO systems. Nevertheless, we have discussed the performance of downlink
NOMA for mMIMO in contrast to traditional multiuser MIMO with NOMA by
considering analytical model. Users are grouped into di erent clusters by combining
any two users with same spatial direction or having higher correlation between
their channels but having di erent channel conditions. In addition, we have investigated
the performance of two user per cluster in downlink NOMA with a
base station equipped with large number of antennas. We have used 64 number
of antennas at the BS in the case of massive MIMO NOMA, but in the case of
multiuser MIMO NOMA, we used three di erent con gurations of antennas at
the BS, i.e., three number of antennas at the BS and at the user side. Perfect
channel state information is assumed in both massive MIMO NOMA and multiuser
MIMO NOMA, and we have allocated less power for the near users where
we have allocated more power for the weak users. System capacity or ergodic sum
capacity is the major points that we have considered in order to analyze the performance
of downlink NOMA for massive MIMO systems in contrast to conventional
MIMO systems. The numerical conclusions reveal that NOMA outperforms OMA
in both single cell and multi-cell environments, and multiuser MIMO NOMA outperforms
multiuser MIMO OMA. Moreover, we have also noticed that massive
MIMO NOMA outperforms MIMO NOMA even when the number of antennas at
the BS and at the user side in the case of MIMO NOMA is about twelve. |
en_US |