In telecommunications, handoff, also known as handover, is the process of transferring an ongoing call or data session from one channel or cell to another without interruption. Different types of handoff techniques are employed in various communication systems to ensure seamless mobility. Here are the main types of handoff in telecom:
1. Intra-Cell Handoff (Soft Handoff):
- Description: Intra-cell handoff, also known as soft handoff, occurs within the same cell. It involves transferring a mobile device’s connection between different channels or sectors within the same base station.
- Use Case: Soft handoff is commonly used to maintain a continuous connection as a mobile device moves within the coverage area of a single base station.
2. Inter-Cell Handoff (Hard Handoff):
- Description: Inter-cell handoff, or hard handoff, takes place when a mobile device moves from the coverage area of one base station to another. It involves disconnecting from the current base station and establishing a connection with a new one.
- Use Case: Hard handoff is essential for ensuring uninterrupted communication as a mobile device transitions between different cells or sectors within a cellular network.
3. Intra-System Handoff:
- Description: Intra-system handoff involves transferring a call or data session between different systems or technologies within the same network. For example, moving from a cellular network to a Wi-Fi network.
- Use Case: In scenarios where multiple access technologies coexist, intra-system handoff allows for seamless connectivity as a mobile device switches between them.
4. Inter-System Handoff:
- Description: Inter-system handoff occurs when a mobile device transitions between different communication systems or networks, such as moving from a cellular network to a satellite-based network.
- Use Case: Inter-system handoff enables mobility across diverse communication infrastructures, ensuring continuous connectivity during transitions between different networks.
5. Mobile-Assisted Handoff:
- Description: In mobile-assisted handoff, the mobile device actively participates in the handoff decision-making process. It measures signal quality and reports information to the network, helping in determining the appropriate target cell for handoff.
- Use Case: Mobile-assisted handoff is beneficial for optimizing handoff decisions based on real-time signal conditions observed by the mobile device.
6. Network-Controlled Handoff:
- Description: In network-controlled handoff, the network infrastructure makes decisions about when and where to perform handoffs based on signal strength, load balancing, and other network parameters.
- Use Case: Network-controlled handoff is useful for centralized management of handoff decisions, optimizing the overall network performance.
The choice of handoff type depends on the specific requirements of the communication system, including factors such as mobility patterns, network architecture, and the coexistence of different technologies. Each type of handoff is designed to address specific challenges associated with maintaining connectivity during user mobility within a telecommunication network.