Handover in Mobile Computing

Handover and its Types

1. HANDOVER

2. PURPOSE OF HANDOVER When the phone is moving away from the area covered by one cell and entering the area covered by another cell the call is transferred to the second cell in order to avoid call termination.

3. PURPOSE OF HANDOVER W hen the capacity for connecting new calls of a given cell is used up and an existing or new call from a phone, is transferred to that cell in order to free-up some capacity in the first cell for other users.

4. DEFINITION A handover is a process in telecommunications and mobile communications in which a connected cellular call or a data session is transferred from one cell site (base station) to another without disconnecting the session.

5. Types of Handovers a) intra-cell handover Here the source and the target are one and the same cell and only the used channel is changed during the handover. Such a handover, in which the cell is not changed, is called intra-cell handover .

6. Types of Handovers b) I nter-cell handover When the source and the target cells may be served from two different cell sites or from one and the same cell site Such a handover, in which the source and the target are different cells is called inter-cell handover.

7. Types of Handovers c) Hard Handover An instantaneous handover in which the existing connection is terminated and the connection to the destination channel is made. It is also known as a break-before-make handover. The process is so instantaneous that the user does not hear any noticeable interruption.

8. Types of Handovers d) Soft Handover A substantial handover where the connection to the new channel is made before the connection from the source channel is disconnected. This type of handover is very effective in poor coverage areas