Sign in Subscribe

2g wireless network

Last updated on 


Certainly! A 2G (Second Generation) wireless network, particularly based on the GSM (Global System for Mobile Communications) standard, involves various technical aspects that enable mobile communication. Let's explore these technical details in-depth:

1. Modulation and Access Techniques:

a. GMSK Modulation:

  • 2G networks, including GSM, commonly use Gaussian Minimum Shift Keying (GMSK) modulation for radio transmission.
  • GMSK is a form of frequency-shift keying (FSK) that ensures signal integrity in the presence of noise.

b. Frequency Division Multiple Access (FDMA) and Time Division Multiple Access (TDMA):

  • FDMA is used to divide the frequency spectrum into multiple channels.
  • TDMA further divides each channel into time slots, allowing multiple users to share the same frequency.

2. Network Architecture:

a. Mobile Station (MS):

  • Represents the user's mobile device, which includes the Mobile Equipment (ME) and the Subscriber Identity Module (SIM).

b. Base Station Subsystem (BSS):

  • Base Transceiver Station (BTS):
    • Manages the radio communication with mobile devices within its coverage area.
    • Transmits and receives voice and data signals.
  • Base Station Controller (BSC):
    • Manages multiple BTS units.
    • Responsible for handovers, frequency hopping, and resource allocation.

3. Core Network Components:

a. Mobile Switching Center (MSC):

  • Switching Function:
    • Manages call setup, release, and handovers.
    • Responsible for routing calls between mobile users and to external networks.
  • Home Location Register (HLR):
    • Database storing subscriber information, including user profiles, subscription details, and current location.
  • Visitor Location Register (VLR):
    • Temporarily stores information about subscribers currently within the jurisdiction of the MSC.

4. Channel Allocation:

a. GSM Channels:

  • Traffic Channels (TCH):
    • Used for carrying voice and user data during active calls.
  • Control Channels:
    • Broadcast Control Channel (BCCH): Carries information about the cell.
    • Common Control Channel (CCCH): Used for signaling and system control.

5. Data Services:

a. General Packet Radio Service (GPRS):

  • Packet-Switched Data:
    • GPRS is introduced to provide basic packet-switched data services.
    • Enables more efficient use of network resources compared to circuit-switched data.

6. Security:

a. Subscriber Identity Module (SIM):

  • Contains subscriber-specific information.
  • Used for authentication and encryption of communication.

b. A5 Encryption Algorithm:

  • Used to secure voice calls and data transmissions.

7. Handovers:

a. Intra-BSC Handover:

  • Within the Same BSC:
    • Handover between different BTS units controlled by the same BSC.

b. Inter-BSC Handover:

  • Between Different BSCs:
    • Handover involving BTS units controlled by different BSCs.

8. Evolution:

a. Transition to 3G:

  • The evolution from 2G to 3G involves the adoption of new technologies such as Wideband Code Division Multiple Access (WCDMA) and the introduction of packet-switched networks for improved data services.

Summary:

A 2G wireless network, particularly based on the GSM standard, employs GMSK modulation, FDMA, and TDMA for channel access. It consists of mobile stations (MS), base station subsystems (BSS) with base transceiver stations (BTS) and base station controllers (BSC), and core network components like the mobile switching center (MSC), home location register (HLR), and visitor location register (VLR). Channel allocation involves traffic and control channels, and the introduction of GPRS brings packet-switched data services. Security is ensured through the use of SIM cards and encryption algorithms. The network supports handovers within and between base station controllers. The evolution from 2G to 3G represents a progression toward more advanced technologies and improved data services.