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What is GERAN in LTE?

GERAN, or GSM/EDGE Radio Access Network, represents a key component in the evolution of mobile communication technologies, specifically in the context of LTE (Long-Term Evolution) networks. GERAN is a legacy radio access network associated with 2G (Second Generation) and 2.5G mobile networks, primarily based on GSM (Global System for Mobile Communications) and Enhanced Data rates for GSM Evolution (EDGE) technologies. This detailed explanation will explore the characteristics, functions, and the interplay of GERAN with LTE networks.

1. Introduction to GERAN:

  • Evolution of Mobile Networks: GERAN emerged during the evolution of mobile networks from 2G to more advanced technologies.
  • GSM and EDGE Technologies: GERAN is based on the GSM standard, which provided the foundation for 2G networks, and the subsequent enhancement, EDGE, which brought higher data rates to 2.5G networks.

2. Key Components and Characteristics:

  • Base Station Subsystem (BSS): GERAN consists of a Base Station Subsystem, which includes Base Transceiver Stations (BTS) responsible for radio communication with mobile devices.
  • Mobility Management and Call Control: GERAN incorporates mobility management and call control functionalities, enabling seamless handovers and call setup procedures.

3. Functions of GERAN in LTE Evolution:

  • Interworking with LTE: As mobile networks evolved to LTE, GERAN played a transitional role by providing legacy services and interworking with newer LTE technologies.
  • Circuit-Switched Services: GERAN continued to support circuit-switched services such as voice calls, which were prevalent in 2G networks.

4. Interworking with GSM and LTE:

  • Dual Connectivity: In the LTE evolution, dual connectivity allowed mobile devices to simultaneously connect to both GERAN (GSM/EDGE) and LTE networks.
  • Efficient Handovers: GERAN and LTE networks were designed to facilitate efficient handovers, allowing devices to seamlessly switch between the legacy and modern networks.

5. Coverage Enhancement:

  • Coverage in Challenging Environments: GERAN provided valuable coverage in areas where LTE signals might be weaker, ensuring a more consistent user experience in challenging radio environments.

6. Sunset of GERAN:

  • Migration to LTE-only Networks: With the ongoing migration towards LTE and beyond, mobile operators have been phasing out older technologies like GERAN.
  • Spectrum Refarming: Spectrum initially allocated to GERAN has been refarmed for LTE and 5G deployments, optimizing the use of frequency bands for newer technologies.

7. Impact on Legacy Services:

  • Transition to VoLTE: As LTE networks introduced Voice over LTE (VoLTE) for high-quality voice calls, the reliance on circuit-switched services provided by GERAN diminished.

8. Coexistence with 2G and 3G Networks:

  • Support for Legacy Devices: GERAN continued to support legacy 2G and 3G devices, ensuring backward compatibility for older mobile devices.
  • Global Roaming: The coexistence of GERAN with 2G and 3G networks allowed for global roaming capabilities, supporting international travelers with diverse device capabilities.

9. Evolution Beyond GERAN:

  • Advancements in LTE: LTE technologies, including LTE Advanced and LTE Advanced Pro, have brought significant advancements in terms of data rates, spectral efficiency, and network capacity compared to GERAN.


GERAN, rooted in the GSM and EDGE technologies of 2G and 2.5G networks, played a vital role in the evolution of mobile communication. As LTE networks became predominant, GERAN facilitated a smooth transition, supporting legacy services and devices. However, with the ongoing evolution towards advanced technologies like 5G, the significance of GERAN has diminished, and mobile operators are focusing on LTE and 5G deployments to meet the growing demands for higher data rates and enhanced services.

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