Handover Summary for 2G, 3G, LTE, 5G & 6G

RAN
, , ,
1

The process of transferring an ongoing call, data session, or n/w connection from one cell or radio frequency to another. This occurs when a mobile device moves out of the coverage area of one cell or when network conditions change

  1. Handover in 2G (GSM): when a mobile device moves from one GSM cell (base station) to another. It’s typically between two cells operating on the same frequency or adjacent ones.

    • Types:
      • Intra-Cell Handover: Within the same base station, changing channels or time slots
      • Inter-Cell Handover: Between two different base stations
      • Inter-Frequency Handover: Between two cells operating on different frequencies.
      • Hard Handover: The connection to the old cell is broken before establishing the new one (break-before-make)

  2. Handover in 3G (UMTS) : its Introduced the concept of “soft handover,” where a device can connect to multiple base stations simultaneously.

    • Types:
      • Soft Handover: The mobile device maintains connections with more than one cell during the handover (make-before-break).
      • Softer Handover: When a device connects to two sectors of the same cell.
      • Hard Handover: Like in 2G, but less frequent due to the soft handover approach.

  3. Handover in 4G/LTE: Its use hard handover, similar to GSM but with faster and more efficient transitions due to its all-IP network design. LTE doesn’t have soft handover, as the system is optimized to handle handovers without requiring multiple connections.

    • Types:

      • Intra-LTE Handover: Between LTE cells operating on the same or different frequencies.
      • Inter-RAT Handover: Between LTE and 3G/2G networks.
      • X2-Based Handover: Handover between eNodeBs (LTE base stations) that have a direct interface.
      • S1-Based Handover: Handover involving the core network (MME and SGW), typically when the eNodeBs don’t have a direct connection.

    • When: LTE handovers are triggered when the signal quality drops below a certain threshold, and the device connects to the strongest neighboring cell.

  4. Handover in 5G (NR): Introduces more advanced handover mechanisms, supporting ultra-reliable low-latency communication (URLLC), massive machine-type communication (mMTC), and enhanced mobile broadband (eMBB). 5G handovers are seamless and aim to maintain service quality across diverse use cases.

    • Types:

      • Intra-NR Handover: Within the 5G network.
      • Inter-NR Handover: Between different frequency bands within 5G.
      • Inter-RAT Handover: Between 5G and 4G or even 3G/2G, ensuring backward compatibility.
      • Dual Connectivity: In 5G, dual connectivity allows a device to be connected to both LTE and 5G at the same time, providing a smoother transition.

    • When: 5G handovers can be triggered by user movement, load balancing (optimizing network resources), or switching between different frequency bands (e.g., between sub-6 GHz and mmWave).

  5. Expected Features of Handover in 6G:

    • AI-Driven Handover Decisions
    • Multi-Layer Handover
    • Handover at Terahertz Frequencies
    • Edge-Enabled Handover

Handover Summary for 2G, 3G, LTE, 5G & 6G
Handover Summary for 2G, 3G, LTE, 5G & 6G1250×586 65.2 KB

LinkedIn: :point_down:

2

Appreciate the effort put into explaining the topic. It will definitely help students and working professionals. We also provide similar types of articles on TechLTE World, covering topics such as RACH, ORAN, LTE, 5G, protocol testing and handover procedures etc. These resources are very useful for learners, engineers, and anyone looking to strengthen their telecom protocol knowledge.