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<div class="div">
<h2>WCDMA RAN cell measurements for GSM-WCDMA inter-system
handover</h2>

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<div class="topic">
<h3>WCDMA
RAN cell measurement and reporting</h3>

<p>The dual-mode GSM/WCDMA mobile is able to measure the signal
levels of the neighbour WCDMA RAN cells when it is in idle state and camped
on a GSM cell. The information of the cells is sent to the mobile in System
Information type 2 quater (SI 2quater) messages or/and in Packet System information
type 3 quater (PSI 3quater) messages.</p>


<p>The SI 2quater messages are sent to the mobile only if
the serving GSM cell has WCDMA RAN neighbour cells. The message is sent on
the BCCH and it may contain more than one instance.</p>


<p>The PSI 3quater messages are sent to the mobile only if
the serving GSM cell has WCDMA RAN neighbour cells. The message is sent on
the PBCCH and it may contain more than one instance.</p>


<p>The non-GPRS capable dual mode GSM/WCDMA mobiles are allowed
and also forced to measure the WCDMA RAN neighbours in idle state, if the
RXLEV of the serving GSM cell is below or above the threshold <span class="parameter-sem">Threshold
To Search WCDMA RAN Cells</span>.</p>


<p>The GPRS capable dual mode GSM/WCDMA mobiles are allowed
and also forced to measure the WCDMA RAN neighbours in idle state if the RXLEV
of the serving GSM cell is below or above the threshold <span class="parameter-sem">GPRS
Threshold To Search WCDMA RAN Cells</span>.</p>


<p>Measurement parameters of the WCDMA RAN neighbours are
sent to a dual mode GSM/WCDMA mobile in Measurement Information (MI) message.
The mobile is allowed and also forced to measure and report the WCDMA RAN
neighbours in dedicated state if the RXLEV of the serving GSM cell is below
or above the threshold <span class="parameter-sem">Threshold For Multi-RAT MS</span>.</p>


<p>The network sends the MI message to the mobile on the SACCH.
If not all information fits into one message, the remaining information is
sent in other instances of this message. The neighbour cell list is based
on the SI 2quater or PSI 3quater message and built by the mobile. It is used
for reporting when the mobile enters the dedicated state, until the mobile
has received all instances of Measurement Information messages that contain
"3G Neighbour Cell Description" information element.</p>


<p>Information about WCDMA RAN cells is included in SI 2quater,
PSI 3quater and MI messages only if the cells are defined as neighbour WCDMA
RAN cells for the serving GSM cell. The dual mode GSM/WCDMA mobiles are able
to find and identify a WCDMA RAN cell by the following information:</p>


<ul>
<li><p><span class="parameter-sem">WCDMA Downlink
Carrier Frequency</span></p>
</li>
<li><p><span class="parameter-sem">Scrambling Code</span></p>
</li>
<li><p><span class="parameter-sem">Downlink Transmission
Diversity</span></p>
</li>
</ul>


<p>You can define the maximum number of the neighbour WCDMA
RAN cells that are included by the mobile in the list of the strongest cells
in a measurement report which is sent to the radio network. You can do this
with the parameter <span class="parameter-sem">Number Of Measured FDD Cells</span>.
The mobiles are ordered to report to the BSC by using Ec/Io as the measurement
quantity.</p>


<p>The number of WCDMA RAN cells from which the mobile is
able to perform neighbour cell measurements depends on the number of frequencies
used.</p>


<p>According to the 3GPP standard the allowed reporting time
is increased by five seconds for each additional WCDMA RAN frequency in the
neighbour cell list. However, multiple WCDMA RAN cells on the same frequency
in the neighbour cell list do not increase the allowed reporting time. This
means that if there are WCDMA RAN neighbours in more than one WCDMA RAN frequency,
there are going to be delays in the neighbour cell reporting.</p>
</div>


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<div class="topic">
<h3>Bookkeeping
and averaging of the CPICH Ec/No of the neighbour WCDMA RAN cell</h3>

<p>The BSC averages the signal level of the neighbour WCDMA
RAN cells (ECNO_NCELL(n)) only at the time when the averaged results are needed
for the decision procedure. The averaging procedure is able to take into account
the maximum of 32 most recent measurement samples per neighbour WCDMA RAN
cell and maintain the last 32 measurement samples of up to 32 neighbour WCDMA
RAN cells per a serving GSM cell.</p>


<p>The measured value replaces RXLEV in the measurement reports.</p>
</div>


<a name="dec2315283213" shape="rect"></a>
<div class="topic">
<h3>Averaging
procedure of the CPICH Ec/No of the neighbour WCDMA RAN cell</h3>

<p>The averaging procedure is controlled by the following
parameters:</p>


<ol class="type-odd">
<li type="1"><p><span class="parameter-sem">Adjacent WCDMA
RAN Cell Averaging Window Size</span> determines the averaging window size
which is used for calculating averaged values from downlink (neighbour WCDMA
RAN cell) signal level measurements for handover threshold comparison and
decision. The range of the averaging window size is from 1 to 32 SACCH multiframe
periods, where the value 1 means that there is basically no averaging at all.</p>
</li>
<li type="1"><p><span class="parameter-sem">Number Of WCDMA
RAN Zero Results</span> indicates the maximum number of zero results that can
be omitted when the measurement results of the neighbour WCDMA RAN cells are
averaged. The range of the parameter is from 0 to 32 zero results. </p>
</li>
<li type="1"><p><span class="parameter-sem">WCDMA RAN All
Cells Avg</span> indicates whether the measurement results are averaged for
every neighbour WCDMA RAN cell (value is 'yes') or only for the maximum of
three cells which are the best according to the last measurement sample (value
is 'no'). </p>
</li>
</ol>


<p>The averaging parameters are controlled on a cell-by-cell
basis. The BSC may average the signal level of the neighbour WCDMA RAN cells
already after the first received measurement sample.</p>
</div>


<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=nov1521223413#nov1521223413" onclick="sync(this);return true" shape="rect">Overview of GSM-WCDMA Inter-System Handover</a></p>
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