We know 5G networks in deploying all over the world gradually. Now great challenge to engineers and scientists is to replace existing 4G network to 5G network. But the process is time consuming and costly (not economic). That's why it takes a decade to bring completely new 'G' (generation) in telecom industry. If we want to deploy new generation suddenly then it will not be economic. One of the many reason is customers will not be suddenly change their smartphones that supports the previous 'G' (say 4G LTE). If we suddenly deploy complete 5G networks then telecom operators will not get enough customers. That will badly impact their business model. So, it is required nearly a decade to deploy a new mobile wireless generation.
5G is not exception of that. Nowadays, we are enabling 5G facility with the help of existing 4G networks. Obviously, their will be added some new features of 5G. For that, we have to integrate some new equipment to the existing 4G networks. When 5G is operated with the help of existing previous networks (i.e., existing 4G networks) then it is called non standalone (non-SA) 5G network. Oppositely, when 5G is deployed completely as a new network and without the help of previously existing network then it is called standalone (SA) network.
