  In order to meet the increasing demands of high data rate and low latency
cellular broadband applications, plans are underway to roll out the Fifth
Generation (5G) cellular wireless system by the year 2020. This paper proposes
a novel method for adapting the Third Generation Partnership Project (3GPP)'s
5G architecture to the principles of Software Defined Networking (SDN). We
propose to have centralized network functions in the 5G network core to control
the network, end-to-end. This is achieved by relocating the control
functionality present in the 5G Radio Access Network (RAN) to the network core,
resulting in the conversion of the base station known as the gNB into a pure
data plane node. This brings about a significant reduction in signaling costs
between the RAN and the core network. It also results in improved system
performance. The merits of our proposal have been illustrated by evaluating the
Key Performance Indicators (KPIs) of the 5G network, such as network attach
(registration) time and handover time. We have also demonstrated improvements
in attach time and system throughput due to the use of centralized algorithms
for mobility management with the help of ns-3 simulations.
