Soft handover is a critical feature in mobile communication systems that allows seamless transition and uninterrupted service as a mobile device moves between cells or base stations. It enhances call quality, coverage, and reliability. Here’s a pointwise description of soft handover in mobile technology:

1. Handover: Handover, also known as handoff, is the process of transferring an ongoing call or data session from one base station (cell) to another as a mobile device moves. It ensures uninterrupted connectivity and optimal signal quality.
2. Cellular Network Architecture: Cellular networks consist of multiple cells, each served by a base station or cell site. Cells are designed to provide coverage within a specific geographic area. When a mobile device moves from one cell to another, a handover is required to maintain the connection.
3. Hard Handover: In traditional handover scenarios, a hard handover involves a mobile device completely disconnecting from the serving base station and establishing a new connection with the target base station. During the transition, there may be a brief interruption in the call or data session.
4. Soft Handover Concept: Soft handover improves upon the hard handover by allowing a mobile device to be simultaneously connected to multiple base stations during the handover process. The device maintains connections with both the serving and target base stations, ensuring continuous communication.
5. Overlapping Coverage: Soft handover is possible when cells have overlapping coverage areas, allowing a mobile device to receive signals from multiple base stations at the same time. This overlapping coverage is intentional and designed to facilitate soft handover.
6. Signal Measurement: The mobile device continuously measures the received signal strength from neighboring base stations. It compares these measurements with the serving base station’s signal strength to determine if a soft handover should be initiated.
7. Signal Threshold: A signal threshold is set to determine when a mobile device should start the soft handover process. If the received signal strength from a neighboring base station exceeds the threshold while maintaining a minimum signal quality with the serving base station, the soft handover process begins.
8. Soft Handover Region: The area where a mobile device is connected to multiple base stations is known as the soft handover region. It typically occurs when the mobile device is at the edge of the coverage area of the serving base station and within the coverage area of neighboring base stations.
9. Multiple Transmissions: During soft handover, the mobile device simultaneously receives and transmits signals to both the serving and target base stations. This enables seamless handover without interruption in the ongoing call or data session.
10. Signal Combining: The received signals from the multiple base stations are combined at the mobile device to improve the signal quality. This technique, called signal combining or diversity combining, helps mitigate signal fading and interference effects.
11. Radio Resource Management: Soft handover requires efficient management of radio resources. The serving and target base stations coordinate with each other to allocate the necessary radio resources for the soft handover, ensuring optimal utilization and minimal interference.
12. Handover Decision Algorithms: Handover decision algorithms determine when to initiate a soft handover based on signal measurements, quality thresholds, and predefined parameters. These algorithms are implemented in both the mobile device and the network infrastructure.
13. Call Routing: During soft handover, the network infrastructure routes the call or data session through both the serving and target base stations. This allows the network to maintain continuity and prevent call drops during the handover process.
14. Load Balancing: Soft handover can also be utilized for load balancing purposes. By distributing user traffic across multiple base stations, the network can optimize resource utilization and alleviate congestion in specific cells.
15. Inter-System Handover: Soft handover can occur not only within the same cellular network but also between different systems or technologies, such as transitioning from a 3G network to a 4G network. This inter-system soft handover ensures smooth migration and backward compatibility.
16. Handover Triggers: Soft handover can be triggered by various factors, including signal strength, signal quality, network congestion, and mobility speed. These triggers help determine the need for a handover and optimize the handover process.
17. Handover Control: Soft handover is controlled by the network infrastructure, including the base stations and the core network. These entities manage the handover procedures, allocate radio resources, and ensure seamless handover execution.
18. Impact on Network Capacity: Soft handover utilizes additional radio resources due to the simultaneous connection with multiple base stations. This can impact network capacity and require efficient resource allocation to accommodate the increased demand.
19. Continuous Monitoring: Soft handover requires continuous monitoring of signal parameters, network conditions, and user mobility to ensure timely handover initiation and optimal performance.
20. Benefits of Soft Handover: Soft handover provides several benefits, including improved call quality, reduced call drops, extended coverage, increased reliability, and enhanced user experience.

In summary, soft handover is a crucial feature in mobile technology that enables seamless handover between cells or base stations. By allowing simultaneous connections with multiple base stations, it ensures uninterrupted communication and enhances the overall performance and reliability of cellular networks.

Soft handover is a technique used in mobile telecommunications to improve the reliability and quality of voice and data calls. It allows a mobile device to maintain a connection to multiple base stations simultaneously, and then seamlessly hand over from one base station to another as it moves from one cell to another.

Here is a block diagram of a soft handover system:

soft handover system block diagram

The following are the key components of a soft handover system:

• Mobile Device: The mobile device is the user’s device, such as a smartphone or tablet, that communicates with the cellular network.
• Base Stations: The base stations are the fixed infrastructure that communicates with the mobile devices.
• Mobile Switching Center (MSC): The MSC is the central switching point for the cellular network. It is responsible for routing calls between mobile devices, as well as for providing services such as call forwarding and voicemail.
• **Inter-cell Handover Manager (ICH): The ICH is a unit within the MSC that manages soft handovers. It is responsible for monitoring the signal strength and quality of the connections between the mobile device and the base stations, and for triggering a soft handover when necessary.

Soft handover works by the mobile device maintaining a connection to multiple base stations simultaneously. The ICH monitors the signal strength and quality of the connections between the mobile device and the base stations. When the ICH determines that a soft handover is necessary, it triggers a soft handover. The mobile device then seamlessly hands over from one base station to another.

Soft handover provides a number of benefits, including:

• Improved reliability: Soft handover improves the reliability of voice and data calls by providing a backup connection in case the primary connection is lost.
• Improved quality: Soft handover improves the quality of voice and data calls by reducing the risk of dropped calls and by improving the overall signal strength and quality.
• Increased capacity: Soft handover increases the capacity of the cellular network by allowing more mobile devices to be connected simultaneously.