architecture of 2g 3g and 4g
2G (Second Generation):
Architecture Overview:
- Frequency Division Multiple Access (FDMA): 2G systems use FDMA to divide the frequency spectrum into channels, allowing multiple users to share the same frequency band simultaneously.
- Time Division Multiple Access (TDMA): TDMA is employed to divide each frequency channel into time slots. Each user is allocated a unique time slot, and multiple users can share the same frequency without interference.
- Base Station (BS): The BS acts as the interface between the mobile device and the network. It manages the radio communication with the mobile devices within its coverage area.
- Mobile Switching Center (MSC): The MSC is responsible for call processing, call setup, and release, as well as handovers between different cells.
- Home Location Register (HLR) and Visitor Location Register (VLR): These databases store subscriber information. HLR contains the details of subscribers, and VLR contains information about subscribers currently within the jurisdiction of the MSC.
- Authentication Center (AUC): AUC is responsible for verifying the identity of mobile subscribers.
- Equipment Identity Register (EIR): EIR maintains a list of all valid mobile equipment on the network to prevent the use of stolen or unauthorized devices.
3G (Third Generation):
Architecture Overview:
- Wideband Code Division Multiple Access (WCDMA): 3G uses WCDMA for air interface, providing higher data rates and improved spectral efficiency compared to 2G.
- NodeB (Base Station): Replaces the 2G BS, responsible for radio transmission/reception and radio resource management.
- Radio Network Controller (RNC): Manages multiple NodeBs and is responsible for functions like handovers, load balancing, and power control.
- Packet Switched Core Network (PS-CN): Introduces the packet-switched core network, allowing better support for data services.
- UMTS Terrestrial Radio Access Network (UTRAN): Comprises NodeBs and RNCs, providing the radio access network for 3G.
- Core Network (CN): Includes elements like MSC, Serving GPRS Support Node (SGSN), and Gateway GPRS Support Node (GGSN). It supports both circuit-switched and packet-switched services.
- Universal Subscriber Identity Module (USIM): An evolution of the SIM card, providing enhanced security and additional features for 3G networks.
4G (Fourth Generation):
Architecture Overview:
- Orthogonal Frequency Division Multiple Access (OFDMA): 4G uses OFDMA for increased spectral efficiency and higher data rates.
- Evolved NodeB (eNB): Replaces NodeB, providing both LTE and WiMAX radio access.
- Mobility Management Entity (MME): Handles the signaling and connection management, including handovers and location updating.
- System Architecture Evolution (SAE) / Evolved Packet Core (EPC): A flat, all-IP core network that includes elements like the MME, Serving Gateway (SGW), and Packet Data Network Gateway (PDN-GW).
- User Equipment (UE): The mobile device in a 4G network.
- IP Multimedia Subsystem (IMS): Facilitates multimedia services over IP networks.
- Home Subscriber Server (HSS): An evolution of HLR, storing subscriber information in 4G networks.
These architectures reflect the evolution of mobile communication technologies, with each generation bringing improvements in data rates, spectral efficiency, and the ability to support advanced services. The transition from 2G to 4G involves a shift from circuit-switched to packet-switched networks and a migration towards an all-IP architecture.