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TYPES OF HANDOVERS IN

WIRELESS

COMMUNICATION

PRESENTED BY:- SACHIN ANAND

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INTRODUCTION TO HANDOVER

Process of transferring an ongoing call or data session fromone channel connected to the core network to another.

In satellite communications it is the process of transferringsatellite control responsibility from one earth station to anotherwithout loss or interruption of service.

American organizations such as 3GPP2 & cdma-2000 usesterm HANDOFF.

International and European organisations such as ITU-T, IETF,ETSI and 3GPP, GSM and UMTS uses the term HANDOVER.

BS 1 BS 2

Mobile

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PURPOSE

To avoid call termination when the phone gets outside therange of the first cell.

Free-up some capacity a cell for other users.

In non-CDMA networks, phone is using same channel may getinterrupted so, different channel is allocated in same channel.

Again in non-CDMA network, fast traveling user is connected tolarge umbrella type cell in order to minimise the frequency ofthe handoffs due to this movement.

In CDMA network SOFT HANDOFF may be induced in order to

reduce the interference to a smaller neighbouring cell due to the"near-far" effect even when the phone still has an excellentconnection to its current cell.

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LAYOUT OF NETWORK

Areas divided into cells.

- Each served by its own antenna(s).

- Band of frequencies allocated.

- Cells set up such that antennas ofall neighbors are equidistant

(hexagonal pattern).

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TYPES OF HANDOVER HARD HANDOVER:-

# channel in the source cell is released and only thenthe channel in the target cell is engaged.

# for this reason such handoffs are also known asbreak-before-make.

#minimize the disruption to the call.

SOFT HANDOVER:-

# channel in the source cell is retained and used for awhile in parallel with the channel in the target cell.

# connection to the target is established before theconnection to the source is broken, hence this handoff

is calledmake-before-break

.

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Handover Protocols

Full Connection Re-routing.

Route Augmentation (Extension).

Partial Connection Re-routing (Incremental Re-establishment).

Multicast Connection Rerouting.

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Applications:- Ongoing call in a train, car, bus etc.

When your mobile phone is in roaming.

Using internet (GPRS/3G) while travelling.

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Conclusion :

To summarize, soft handoff is advantageous overhard handoff.

The mobile does not lose contact with the systemduring handoff execution.

Ping ponging is eliminated and an extra measureof performance is obtained through diversitycombining to mitigate fading.

Furthermore, autonomous handoff decision ability ,selection diversity, and inherent improvement of

reliable handoffs with fewer unnecessarydecisions, make soft handoff an attractive choicemeriting further study as it is being used in thirdgeneration CDMA.

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THANK YOUfor listening