Subject: Mobile Computing

Difficulty: Medium

Marks: 4 Marks

• When a user is moving from one cell to another cell, while the call is in progress, is called as handoff.
• While performing handoff, mobile station acquires a channel from one base station, how mobile station moves from one cell to another cell, how mobile station requires that base station in new cell will allocate channel to mobile station. If the channel is not available in new cell then the handoff call is blocked.
• This type of blocking is known as "handoff blocking". Handoff blocking can be done due to mobility of the user. New call and handoff call is illustrated in Fig. A person is in network 1, in one of the cell called 'd', may move to cell 'C' thus, it perform handoff call within network 1.
• A person can also move from one network to another network, for example, a person is moving from cell 'd' of network 1 to cell 'b' of network 2.

Types of Handsoff:

1. Soft
2. Hard
3. Delayed
4. Queued 5.Mobile assisted handsoff6