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2g 3g 4g architecture with interfaces

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Let's delve into the architectures of 2G, 3G, and 4G networks, detailing their key components and interfaces.

1. 2G (Second Generation)

Architecture:

  1. Base Station Subsystem (BSS):
    • Base Transceiver Station (BTS): This is the radio equipment (transceivers and antennas) that communicates directly with mobile handsets.
    • Base Station Controller (BSC): Manages one or more BTS units. It handles call setup, handovers, and allocation of radio channels.
  2. Network Switching Subsystem (NSS):
    • Mobile Switching Center (MSC): Connects the mobile network to other networks, like the Public Switched Telephone Network (PSTN).
    • Visitor Location Register (VLR): Stores information about roaming mobiles in the area.
    • Home Location Register (HLR): Database that contains subscriber information and location data.

Interfaces:

  • Um Interface: Between the mobile station (MS) and the BTS using the GSM air interface standard.
  • Abis Interface: Between the BTS and BSC. It carries voice and signaling information.
  • A Interface: Between BSC and MSC. It allows the BSC and MSC to communicate for call control and mobility management.
  • BSSMAP (Base Station System Management Application Part): This is a part of the A interface and helps in signaling between MSC and BSS.

2. 3G (Third Generation)

Architecture:

  1. Radio Access Network (RAN):
    • Node B: Equivalent to BTS in 2G, responsible for transmission and reception of data.
    • RNC (Radio Network Controller): Similar to BSC in 2G, it controls multiple Node Bs and manages resources.
  2. Core Network:
    • MSC (Mobile Switching Center): Enhanced for 3G to support voice and data.
    • Serving GPRS Support Node (SGSN): Manages mobile connections for data services.
    • Gateway GPRS Support Node (GGSN): Serves as a gateway between the 3G network and external data networks like the internet.

Interfaces:

  • Uu Interface: Between the user equipment (UE) and Node B.
  • Iu Interface: Between RNC and core network elements like MSC and SGSN.
  • Iur Interface: Between two RNCs for inter-RNC communication.
  • Gb Interface: Between SGSN and GGSN.
  • Gi Interface: Between GGSN and external data networks.

3. 4G (Fourth Generation - LTE)

Architecture:

  1. Evolved UTRAN (eUTRAN):
    • eNodeB: Equivalent to Node B but with a simplified architecture. Handles both user plane (data) and control plane (signaling) functions.
    • MME (Mobility Management Entity): Manages mobility and authentication for the UE.
    • S-GW (Serving Gateway): Routes and forwards user data packets.
    • P-GW (Packet Gateway): Serves as the point of exit and entry for user data between the LTE network and external networks.

Interfaces:

  • S1-MME and S1-U: Between eNodeB and MME, and between eNodeB and S-GW respectively.
  • X2 Interface: Between two eNodeBs for handovers and other inter-cell operations.
  • S5/S8 Interface: Between S-GW and P-GW, and between S-GW of visited and home networks for roaming.