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<title>Overview of GSM-WCDMA Inter-System Handover</title>
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<h1>Overview of GSM-WCDMA Inter-System Handover</h1>

<p>An inter-system handover is a handover (HO) between <a href="NED?action=retrieve&amp;identifier=general_glossary&amp;edition=13&amp;language=en&amp;coverage=global&amp;encoding=xhtml_1_0&amp;component=data&amp;item=data&amp;pointer=id05086#id05086" onclick="openSmallPopup(event,'NED?action=retrieve&amp;identifier=general_glossary&amp;edition=13&amp;language=en&amp;coverage=global&amp;encoding=xhtml_1_0&amp;component=data&amp;item=data&amp;pointer=id05086#id05086');return false" shape="rect" target="_blank">GSM</a> and <a href="NED?action=retrieve&amp;identifier=general_glossary&amp;edition=13&amp;language=en&amp;coverage=global&amp;encoding=xhtml_1_0&amp;component=data&amp;item=data&amp;pointer=id010040#id010040" onclick="openSmallPopup(event,'NED?action=retrieve&amp;identifier=general_glossary&amp;edition=13&amp;language=en&amp;coverage=global&amp;encoding=xhtml_1_0&amp;component=data&amp;item=data&amp;pointer=id010040#id010040');return false" shape="rect" target="_blank">WCDMA</a> networks.
The change of GSM and WCDMA network can also happen in idle mode when there
is cell re-selection. The cell re-selection is also done for packet data even
if the mobile is not in idle mode.</p>


<p>The inter-system handover from GSM to WCDMA is initiated
by the GSM radio network, and the inter-system handover from WCDMA to GSM
is initiated by the WCDMA radio network (that is, <a href="NED?action=retrieve&amp;identifier=general_glossary&amp;edition=13&amp;language=en&amp;coverage=global&amp;encoding=xhtml_1_0&amp;component=data&amp;item=data&amp;pointer=id010144#id010144" onclick="openSmallPopup(event,'NED?action=retrieve&amp;identifier=general_glossary&amp;edition=13&amp;language=en&amp;coverage=global&amp;encoding=xhtml_1_0&amp;component=data&amp;item=data&amp;pointer=id010144#id010144');return false" shape="rect" target="_blank">UTRAN</a>).</p>


<p>In order for an operator to be able to provide seamless
coverage in areas where WCDMA is not available, for example in rural areas,
inter-system handovers provide a method of extending the radio network coverage
area by making a handover between the WCDMA network and GSM network.</p>


<p>Additionally, in situations where the WCDMA network and
GSM network overlap, an inter-system handover can be made in order to balance
or control the traffic load between the systems. An example of this is where
the speech connection is handed over to the GSM network to allow data connections
to be handled by the WCDMA network.</p>


<p>The inter-system handovers are hard handovers and therefore
cause a temporary disconnection of the real time (RT) radio access bearer.</p>


<p>The inter-system handovers are also network-evaluated handovers
(<a href="NED?action=retrieve&amp;identifier=general_glossary&amp;edition=13&amp;language=en&amp;coverage=global&amp;encoding=xhtml_1_0&amp;component=data&amp;item=data&amp;pointer=id013667#id013667" onclick="openSmallPopup(event,'NED?action=retrieve&amp;identifier=general_glossary&amp;edition=13&amp;language=en&amp;coverage=global&amp;encoding=xhtml_1_0&amp;component=data&amp;item=data&amp;pointer=id013667#id013667');return false" shape="rect" target="_blank">NEHO</a>). However, the user equipment (UE) must be capable
of supporting inter-system handovers completely before GSM-WCDMA Inter-System
Handover can be used.</p>


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<dl class="note-notification">
<dt class="note-caption">Note</dt>
<dd>GSM-WCDMA Inter-System Handover is application software.</dd>
</dl>


<p><a href="NED?action=retrieve&amp;identifier=dn02210994&amp;edition=5&amp;language=en&amp;coverage=global&amp;encoding=xhtml_1_0&amp;component=data&amp;item=data&amp;pointer=ned_2#ned_2" onclick="sync(this);return true" shape="rect">GSM-WCDMA cell re-selection and inter-system handover</a></p>


<p><a href="NED?action=retrieve&amp;identifier=dn02210994&amp;edition=5&amp;language=en&amp;coverage=global&amp;encoding=xhtml_1_0&amp;component=data&amp;item=data&amp;pointer=ned_3#ned_3" onclick="sync(this);return true" shape="rect">WCDMA–GSM cell re-selection and inter-system handover</a></p>


<p><a href="NED?action=retrieve&amp;identifier=dn02210994&amp;edition=5&amp;language=en&amp;coverage=global&amp;encoding=xhtml_1_0&amp;component=data&amp;item=data&amp;pointer=ned_4#ned_4" onclick="sync(this);return true" shape="rect">Benefits of GSM-WCDMA Inter-System Handover</a></p>
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