To address the ever increasing high data rate and
connectivity requirements in the next generation 5G wireless
network, novel radio access technologies (RATs) are actively
explored to enhance the system spectral efficiency and connectivity. As a promising RAT for 5G cellular networks, nonorthogonal multiple access (NOMA) has attracted extensive
research attentions. Compared with orthogonal multiple access
(OMA) that has been widely applied in existing wireless communication systems, NOMA possesses the potential to further
improve system spectral efficiency and connectivity capability.
This paper develops analytical fr a meworks for NOMA downlink
and uplink multi-cell wireless systems to evaluate the system
outage probability and average achievable rate. In the downlink
NOMA system, two different NOMA group pairing schemes are
considered, based on which theoretical results on outage and
achievable data rates are derived. In the uplink NOMA, revised
back-off power control scheme is applied and outage probability
and per UE average achievable rate are derived. As wireless
networks turn into more and more densely deployed, inter-cell
interference has become a dominant capacity limiting factor but
has not been addressed in most of the existing NOMA studies.
In this paper a stochastic geometry approach is used to model a
dense wireless system that supports NOMA on both uplink and
downlink, based on which analytical results are derived either in
pseudo-closed forms or succinct closed forms and are further
validated by simulations. Numerical results demonstrate that
NOMA can bring considerable system-wide performance gain
compared to OMA on both uplink and downlink when properly
designed