Handover, also known as handoff, refers to the automatic transfer of a subscriber's call from one cell to another during a call to prevent disconnection. There are two key aspects: finding an available channel in the next cell while the call is ongoing, and switching fast enough to avoid dropping the call. There are different types of handover including hard/soft based on frequency, and intracell/intercell/inter-BSC/inter-MSC based on area. Hard handover breaks the connection to the source cell before establishing it in the target cell, while soft handover connects to multiple cells simultaneously for a smoother transition.

1. Handover
/handoff
A report by Pragya kumari

2. Handover/handoff
Handover is the automatic transfer of the subscriber from one cell
to another during the call process, without causing any hindrance to
the call. There are two main aspects to this: the necessity to find
a dedicated mode in the next cell as the mobile is on call, and the
switching process being fast enough so as not to drop that call.

3. Types of Handover
According to
frequency
● Hard handover
● Soft handover
According to area
● Intracell handover
● Intercell handover
● Inter bsc handover
● Inter msc handover

4. Hard handover
Is one in which the channel in the source cell is released and only then the
channel in the target cell is engaged. Thus the connection to the source is
broken before or 'as' the connection to the target is made—for this reason
such handovers are also known as break-before-make. Hard handovers are
intended to be instantaneous in order to minimize the disruption to the call.
Soft handover
Soft handover or soft handoff refers to a feature used by the CDMA and W-CDMA
standards, where a cell phone is simultaneously connected to two or more cells
(or cell sectors) during a call. If the sectors are from the same physical
cell site (a sectorised site), it is referred to as softer handoff. This
technique is a form of mobile-assisted handover, for IS-95/CDMA2000 CDMA cell
phones continuously make power measurements of a list of neighboring cell
sites, and determine whether or not to request or end soft handover with the
cell sectors on the list.

5. Intracell handover
•Handover takes place in the same cell from one timeslot to another
timeslot of the same carrier or different carriers( but the same
cell).
•Intra-cell handover is triggered only if the cause is interference.
•Intra-cell handover can be enabled or disabled in a cell.
BSC
Call is handed
from timeslot 3 to timeslot 5
0 1 2 3 4 5 6 7

6. Handover takes place between different cell which are
controlled by the same BSC.
Intra-BSC Handover/ Inter-cell Handover
BSC1
BTS1
Call is handed from timeslot 3
of cell1 to timeslot 1 of cell2 .
Both the cells are controlled
by the same BSC.
0 1 2 3 4 5 6 7
0 1 2 3 4 5 6 7

7. Handover takes place between different cell which are
controlled by the different BSC.
Inter-BSC Handover
BSS1
BTS1
Call is handed from timeslot 3
of cell1 to timeslot 1 of cell2 .
Both the cells are controlled
by the different BSC.
0 1 2 3 4 5 6 7
0 1 2 3 4 5 6 7
BSS2
MSC
BTS2

8. Handover takes place between different cell which are controlled by
the different BSC and each BSC is controlled by different MSC.
Inter-MSC Handover
BSS1
BTS1 Call is handed from timeslot 3
of cell1 to timeslot 1 of cell2 .
Both the cells are controlled
by the different BSC, each BSC
being controlled by different MSC.
0 1 2 3 4 5 6 7
0 1 2 3 4 5 6 7
BSS2
MSC1
BTS2
MSC2

9. Thank you