The RAN is the part of the mobile network responsible for connecting mobile devices to the core network.
It encompasses the infrastructure and technology used to communicate with mobile devices over the airwaves.
Components:
Base Station (BS) or NodeB (in 3G) / eNodeB (in 4G and 5G):
The base station is a key component in the RAN. It consists of radio transceivers and antennas.
In 4G and 5G, the term "eNodeB" is used, where "e" stands for evolved. Each eNodeB is capable of supporting multiple users simultaneously.
Radio Frequency (RF) Components:
RAN involves various RF components like antennas, amplifiers, and filters.
Antennas are crucial for transmitting and receiving signals between the base station and mobile devices.
Radio Protocols:
RAN uses specific protocols for communication, such as LTE (Long-Term Evolution) in 4G and NR (New Radio) in 5G.
These protocols define how data is transmitted wirelessly and how devices communicate with the base station.
Mobile Devices:
Mobile phones and other devices communicate with the RAN using the wireless interface.
They establish connections, handovers, and manage the data transfer with the base station.
Functions:
Wireless Link Management:
RAN manages the wireless links between mobile devices and the base station.
It handles processes like handovers, where a mobile device transitions from one base station's coverage area to another seamlessly.
Resource Allocation:
Allocating resources such as time and frequency slots to different users to ensure efficient use of the available spectrum.
Mobility Management:
Managing the mobility of devices as they move within the network.
Connection Establishment and Release:
Establishing and releasing connections between mobile devices and the network as needed.
Core Network:
Overview:
The Core Network is the central part of a mobile network that manages and routes communication between different RANs and external networks (such as the internet).
Components:
Mobile Switching Center (MSC) / Mobile Switching System (MSS):
Controls the setup, routing, and release of connections between mobile users.
Home Location Register (HLR):
Stores subscriber information, including user profiles and current locations.
Visitor Location Register (VLR):
Keeps track of mobile users within its coverage area.
Serving GPRS Support Node (SGSN):
In 2G and 3G networks, it is responsible for the delivery of data packets from and to the mobile stations within its service area.
Gateway GPRS Support Node (GGSN):
Acts as an interface between the mobile network and external packet-switched networks, such as the internet.
Packet Data Node (PDN):
In 4G and 5G, it handles the delivery of IP packets between the mobile network and external packet-switched networks.
Functions:
Call and Session Management:
Establishing and managing voice and data sessions between users.
Authentication and Authorization:
Verifying the identity of users and authorizing access to network services.
Roaming Support:
Supporting users as they move between different geographical areas and networks.
Billing and Charging:
Handling billing information and charging for network services.
Security:
Implementing security mechanisms to protect user data and the network.
Protocols:
Various protocols such as Signaling System 7 (SS7), Diameter, and Internet Protocol (IP) are used for communication between different core network elements.
