Premise of 5G, is resting on All IP architecture.
Mobile networks have been designed up to this point — for circuit- switched voice. Wireless
networks were designed in a hierarchal fashion to aggregate, authenticate, manage and direct
calls. A BSC aggregates calls from multiple base stations, allocates radio channels, enables
handoffs between base stations and passes on calls to an even more centralized mobile switching
centre. As packet data networks emerged, they were overlaid on the existing voice-centric
architecture, using the BSC for the same mobility management functions and adding the SGSN
and GGSN in the case of GSM/UMTS and a PDSN in the case of CDMA to route and manage
data sessions, as well as to connect to the Internet or appropriate IP network. As data traffic is
increasing rapidly, this voice centric architecture has become cumbersome and harder to manage
with too many network entities. Flat network architecture removes that voice-centric hierarchy
from the network. Instead of overlaying a packet data core on the voice network, separate and
much-simplified data architecture can be implemented that removes the multiple elements from
the network chain. BSC functions are divided between Base station and media gateway router.
Base station will communicate directly via 3GDT (3G direct tunnel) with media gateway over
WAN (Carrier Ethernet, MW, DWDM etc). Some of the functions of BSC/RNC such as Radio
resource management, Radio Bearer Control, and Dynamic allocations of resources will be
handled by base stations, while functions such as Distribution of paging messages, Security will
be function by mobility manager, located in Gateway router.