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Common BCCH System Feature NSN
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7/14/2019 Common BCCH System Feature
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Common BCCH System Feature
Description
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2002546
Nokia GSM/EDGE BSS11 SystemDocumentation Set
7/14/2019 Common BCCH System Feature
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The information in this document is subject to change without notice and describes only theproduct defined in the introduction of this documentation. This document is intended for the useof Nokia's customers only for the purposes of the agreement under which the document issubmitted, and no part of it may be reproduced or transmitted in any form or means without theprior written permission of Nokia. The document has been prepared to be used by professionaland properly trained personnel, and the customer assumes full responsibility when using it.Nokia welcomes customer comments as part of the process of continuous development andimprovement of the documentation.
The information or statements given in this document concerning the suitability, capacity, or performance of the mentioned hardware or software products cannot be considered binding butshall be defined in the agreement made between Nokia and the customer. However, Nokia hasmade all reasonable efforts to ensure that the instructions contained in the document areadequate and free of material errors and omissions. Nokia will, if necessary, explain issueswhich may not be covered by the document.
Nokia's liability for any errors in the document is limited to the documentary correction of errors.NOKIA WILL NOT BE RESPONSIBLE IN ANY EVENT FOR ERRORS IN THIS DOCUMENTOR FOR ANY DAMAGES, INCIDENTAL OR CONSEQUENTIAL (INCLUDING MONETARYLOSSES), that might arise from the use of this document or the information in it.
This document and the product it describes are considered protected by copyright according tothe applicable laws.
NOKIA logo is a registered trademark of Nokia Corporation.
Other product names mentioned in this document may be trademarks of their respectivecompanies, and they are mentioned for identification purposes only.
Copyright © Nokia Corporation 2003. All rights reserved.
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Contents
Contents 3
1 Overview of GSM/EDGE Common BCCH 5
2 System impact of Common BCCH 132.1 Requirements 132.1.1 Hardware Requirements 132.1.2 Software Requirements 142.1.3 Frequency band support for Common BCCH 142.2 Impact on transmission 152.3 Impact on BSS Performance 152.3.1 Common BCCH impact on OMU signalling 152.3.2 Common BCCH impact on TRX signalling 16
2.3.3 Impact on BSC 162.4 User Interface 162.4.1 MMI 162.4.2 BTS parameters 172.4.3 BSC parameters 172.4.4 BSS Parameters 182.5 Impact on NSS 212.6 Impact on OSS 222.7 Impact on Interfaces 242.7.1 Impact on A Interface 242.7.2 Impact on Abis Interface 242.7.3 Impact on Gb Interface 242.8 Feature Interoperability 252.9 Impact on mobile terminals 33
3 Planning Common BCCH 353.1 Common BCCH and handover 353.2 Common BCCH and channel allocation 373.3 SDCCH dimensioning with Common BCCH 39
4 Implementing Common BCCH 414.1 Overview of implementing Common BCCH 414.2 Creating a multiband cell (segment) 424.3 Cancelling the expand of the segment 524.4 Moving a BTS from one segment to another existing segment 56
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Contents
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1 Overview of GSM/EDGE Common BCCH
The Common BCCH feature allows the integration of resources from different
frequency bands into one cell. A common BCCH of a cell is configured in only
one of the bands of operation when resources across all bands are co-located and
synchronized.
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Figure 1. GSM900/GSM1800 Common BCCH configuration
The following frequency band combinations are supported:
. PGSM 900 / EGSM 900
. PGSM 900 / GSM 1800
. PGSM 900 / EGSM 900 / GSM 1800
/ / /
O&M
O&M
Cell 1
GSM900 (BCCH) /GSM1800
Cell 3
GSM900 (BCCH) /GSM1800
Cell 2GSM900 (BCCH) /
GSM1800
Cell 2
Cell 1
Cell 3
BTS-900
BTS-900
BTS-900
BTS-1800
BTS-1800
BTS-1800
GSM900 GSM1800
Synch.
BSC
Abis interface
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. EGSM 900 / GSM 1800
. GSM 800 / GSM 1900.
The BCCH carrier is allowed in any of the supported frequency bands, except that the common BCCH is allowed in the EGSM900 frequency band only if there
is no PGSM900 in use in the network.
Benefits
The following are the benefits of using common BCCH control:
. Improved trunking gain
. Use of signalling channels is optimised by sharing them between bands.
.
The absence of a BCCH channel (in non-BCCH frequency band) leads to areduction of the overall interference and allows more freedom in frequency
allocation with improved quality.
. Reduced number of cells in the network
. Reduced number of Location Area Codes
. Reduced number of neighbouring cells
. Multi-layer network simplified into one-layer network
. Quality improvement due to decreased number of handovers between
frequency layers; calls directed to an appropriate layer in call set-up.
Segment and BTS object
Segment is a new Radio Network Object introduced to support Common BCCH,
Multi-BCF, and EDGE. The properties of a segment are the following:
. A segment equals a telecom cell. Whenever segment is mentioned, it is a
cell as we normally use.
. A segment may consist of several BTS objects.
.
BTSs of a segment are co-located and synchronised.. The maximum number of BTSs in a segment is 32.
The properties of BTS Object are:
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. A BTS in a segment must consist of TRXs of the same frequency band
(PGSM 900, EGSM 900, GSM 1800, GSM 800, GSM 1900 separated).
. A BTS in a segment must consist of TRXs of the same base station site
type (Talk-family and UltraSite separated).
. A BTS in a segment must consist of TRXs of the same radio technology
(GSM and GSM/EDGE separated).
. The maximum number of TRXs in segment is 36.
Figure 2. Segment and BTS Object in Common BCCH
A typical Common BCCHs BTS configuration is shown in the figure. When
considering Common BCCH, segment-specific parameters and BTS specific
parameters should be taken into account. In many cases, BTS and frequency band
are the same but in some case they are different, for example PGSM 900 Talk-
family and PGSM 900 UltraSite must be configured as separate BTSs. Segment
specific, BTS specific and frequency band specific parameters need to be
considered in this case.
The allocation of a dedicated channel (SDCCH or TCH) inside a multiband
segment (that is, with BTSs from different frequency bands) is based on:
BCF BCF BCF
BTS BTS BTS
PGSM 900
PGSM 900
BCCH
EGSM900
GSM 1800
SEGMENT
Segment specificparameters
BTS specific parameters
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. The frequency capabilities of the mobile station
. The prevailing radio conditions of the mobile station
.
The resource situation on each band.
The second condition is evaluated for the secondary frequency band using a new
BTS parameter, nonBCCHLayerOffset.
Mobile frequency capability
Different classes of mobiles can be defined according to their frequency
capabilities.
The information of the frequency capabilities of the mobile station is included in
the Mobile Station Classmark 2 and Mobile Station Classmark 3 Information
Elements.
The Mobile Station Classmark 2 Information includes information on the possible
EGSM 900 capability of the MS. The Mobile Station Classmark 3 Information
Element defines all the frequency bands supported by the MS and the MS power
capabilities in each supported frequency band.
The network receives the Mobile Station Classmark 2 IE in the Establish
Indication message. The Mobile Station Classmark 3 IE is received in the
Classmark Change message. The BSC receives both of these messages while the
related mobile station is on a dedicated signalling channel (SDCCH).
Intra-segment resource usability estimation
When the BSC has received both information about the MS frequency band
capability and about the downlink received BCCH signal level (measurement
report), it defines the usability of different resource types of the segment.
The following formula is used for resource usability estimation whenever a
channel inside the segment has to be assigned (in intra-segment SDCCH-SDCCH
handovers, TCH allocations, or intra-segment TCH-TCH handovers).
RXLEV_DL -nonBCCHLayerOffset>=nonBCCHLayerAccessThreshold
If the MS is on a BCCH layer channel, the RXLEV_DL is the terminal received
signal level on the channel. If the MS is using a non-BCCH layer channel, the
RXLEV_DL is the downlink signal level of the BCCH carrier of the segment.
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Inter-segment resource usability estimation
When the BSC has defined a need for an inter-segment (SDCCH-SDCCH or
TCH-TCH) handover based on the measurements of the serving channel, the
usability of the different resource types of each candidate segment is decided
using the BCCH measurement results for the segment and the values of parameter
nonBCCHLayerOffset for different resource types in the segment according
to the criterion:
AV_RXLEV_NCELL(n) nonBCCHLayerOffset>= RxLevMinCell(n)
where
RxLevMinCell(n) is the level which the signal level in the adjacent segment must
exceed in order for the handover to the adjacent segment to become possible.
In a handover between two BSCs, the radio link measurements related to the
target segment are available on the source side BSC only. It is therefore not
possible to use the radio link measurements to define the usability of the non-
BCCH layer resources on the target side. In this case the decisions are based on
the nonBCCHLayerOffset parameter. If the non-BCCH layer is regarded as a
layer with less coverage (as indicated by the positive value of the
nonBCCHLayerOffset parameter), only BCCH frequency band resources are
used in channel allocation for external handovers.
Restrictions
1. In the band where the BCCH carrier resides, the common BCCH
controlled segments must be the same throughout the whole network.
BCCH is allowed in the EGSM 900 frequency band only if there is no
PGSM 900 frequency band in use in the network.
2. In the Common BCCH feature the BCCH frequency of the segment is
added among the BCCH frequencies that the MS should measure when the
MS is active on the non-BCCH band of the segment. This leads to the
following restrictions:
. There can be only 31 frequencies in an adjacent cell and on BA lists.
.
Only 5 of the strongest neighbours are included in the adjacent cellmeasurements.
3. In a multi-band Common BCCH, the Initial SDCCH channel for a call set-
up is always allocated in the frequency band where also the segment's
BCCH is located.
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When an SDCCH is allocated for an external handover in a multi-band
Common BCCH segment, the search may be restricted among the BCCH
frequency band resources of the segment. This depends on the frequency
band the BCCH is using. If the non-BCCH layer is regarded as a layer with
less coverage (as indicated by the positive value of the
nonBCCHLayerOffset parameter), only BCCH frequency band
resources are used in SDCCH allocation for external handovers.
4. In a multiband Common BCCH segment, the TCH for a FACCH setup is
always allocated in the BCCH frequency band of the segment.
5. The dynamic SDCCH RTSLs can be utilised only in the BCCH frequency
band in a Common BCCH cell. This is due to the fact that the multi-band
capabilities of an accessing MS are not known at the time of the initial
SDCCH allocation.
6. The multi-band MS and the multi-band network support FrequencyHopping within each band of operation. Frequency Hopping between the
bands of operation is not supported.
7. In the segment environment, only the BCCH BTS can have extended area
TRXs.
8. When a TCH is allocated for an external handover in a multiband Common
BCCH segment, the search may be restricted among the BCCH frequency
band resources of the segment. This depends on the frequency band BCCH
is using. If the non-BCCH layer is regarded as a layer with less coverage
(as indicated by the positive value of the nonBCCHLayerOffset
parameter), only BCCH frequency band resources are used in TCHallocation for external handovers.
9. The super-reuse layer of a BTS in a segment with several BTSs can be
accessed only via the regular layer of the BTS.
Handover from super-reuse resources back to the regular layer is not
restricted totally inside the source BTS. But it is limited among the
segment's BTSs that can be regarded as stronger than or equal to the source
BTS (as indicated by the values of the respective
nonBCCHLayerOffset parameters).
Thechild cell concept is not supported in a BSC that has the segment
option enabled.
10. GSM-WCDMA Inter-System Handover and Common BCCH Control.
If the features GSM-WCDMA Inter-System Handover and Common
BCCH Control are used together the maximum amount of adjacent cells
and frequencies in a BA list is 30.
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Common BCCH parameters
See chapter BSS Parameters.
non-BCCHLayerOffset
See chapter BSS Parameters.
Note
Common BCCH is an optional BSS feature.
Common BCCH and handover
Common BCCH and channel allocation
SDCCH dimensioning with Common BCCH
Overview of implementing Common BCCH
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2 System impact of Common BCCH
2.1 Requirements
2.1.1 Hardware Requirements
Table 1. This table indicates whether
the feature requires additional
or alternative hardware or
firmware.
Network
element
Hardware/
Firmware required
BSC No requirements
BTS Yes, RF units are
band specific, and
correct RF units are
needed for the
supported frequency
bands.
TC No requirements
SGSN No requirements
Common BCCH requires a multi band capable terminal.
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2.1.2 Software Requirements
Table 2. Network elements requiredsoftware.
Network
element
Software release
required
MSC No requirements
Nokia NetAct OSS3.1 ED1
(Enhancement
Delivery)
BSC S11
SGSN No requirements
NetAct Planner 4.0
Nokia 2nd Gen. Does not support this
feature
Nokia Talk-family DF6.0
800/1900 Common
BCCH not supported.
Nokia PrimeSite Does not support thisfeature
Nokia MetroSite CXM4.0
Nokia InSite Not supported by
Common BCCH
Nokia UltraSite CX4.0
2.1.3 Frequency band support for Common BCCH
The following frequency bands support Common BCCH:
. GSM 800
. GSM 900
. GSM 1800
. GSM 1900
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For more detailed information, see Overview of GSM/EDGE Common BCCH .
Band Specific Power Controlling Parameters for Common BCCH
The different radio propagation properties of the different frequency bands of a
multiband segment result in different radio coverages of the two bands. The
maximum transmission power for the different frequency bands of a multiband
segment needs to be adjusted separately in order to better maintain connection to
MSs in the segment. Matching the radio coverage to the same size on both bands
of a multiband segment is done by adjusting the maximum transmission power
for the bands separately with Band Specific Power Controlling Parameters.
See Power control parameter handling in BSC parameters.
2.2 Impact on transmission
No impact.
2.3 Impact on BSS Performance
2.3.1 Common BCCH impact on OMU signalling
Table 3. Common BCCH impact on OMU signalling
Network element Impact
BTS No impact
BSC No impact
OSS No impact
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2.3.2 Common BCCH impact on TRX signalling
Table 4. Common BCCH impact on TRX signalling
Network element Impact
BTS No impact
BSC No impact
OSS No impact
2.3.3 Impact on BSC
Table 5. Impact on BSC units
BSC unit Impact
MCMU No impact
BCSU No impact
PCU No impact
2.4 User Interface
2.4.1 MMI
Table 6. MML
Network element Impact
BSC This feature is managed with BSC MMI.
OSS Common BCCH feature has an impact on
OSS.
MSC No impact
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2.4.2 BTS parameters
The feature cannot be managed with BTS MMI.
2.4.3 BSC parameters
Base station controller parameter handling in BSC
The new parameter IntraSegSdcchHoGuard (ISS) is added to BSC handling
MML.
Base transceiver station handling in BSC
New parameters are added to BTS-MML: BTSLoadInSEG (LSEG),
NonBcchLayerOffset (NBL), MsTxPwrMaxCCH1x00 (TXP2),GPRSMsTxPwrMaxCCH1x00 (GTXP2), GPRSNonBcchLayerRxlevUpper
(GPU), GPRSNonBcchLayerRxlevLower (GPL), DirectGPRSAccessThreshold
(DIRE), SegmentId (SEG), and SegmentName (SEGNAME). Parameters
MsTxpwrMaxCCH (TXP1) and GPRSMsTxPwrMaxCCH (GTXP1) are used
only when the BCCH of the segment is either on the GSM800 or GSM900
frequency band.
Handover control parameter handling
New parameters are added to HOC-MML: NonBcchLayerAccessThreshold
(LAR), NonBcchLayerExitThreshold (LER), NonBcchLayerExitThresholdPx
(LEP), NonBcchLayerExitThresholdNx (LEN).
Power control parameter handling
When POC is created, PORTER selects the ALPHA and GAMMA default values
according to the BCCH frequency band of the segment. If there is no BCCH TRX
in the segment, and there are more than one frequency bands in use in the
segment when POC is created, then GSM900 default values are used if there
exists at least one GSM900 or GSM800 BTS in the segment.
See also parameters bsTxPwrMax and bsTxPwrMax1x00 in the table
Common BCCH parameters.
Adjacent cell handling
One new parameter GPRSMsTxPwrMaxCCH1x00 (GTXP2) is added to adjacent
cell handling MML.
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2.4.4 BSS Parameters
Common BCCH parameters
Q3 BSC MML Object Range Default
value
Description
intraSeg
SDCCHGuard
BSC 0 - 255 (s) 255 With this parameter you define the
guard time for attempting an SDCCH
handover from the BCCH BTS
resource layer to another resource
layer in a segment.
btsLoadInSeg BTS 0 - 100(%) 70 With this parameter you determine
the load limit for a BTS. It is used in
controlling the load distribution
between BTSs in a segment.
SegmentId BTS - Same value
as bts_id
The value range depends on the BSC
hardware configuration and the
corresponding options.
segmentName BTS 1 - 15
characters
Same name
as BTS's
name
With this parameter you identify the
segment by its name.
nonBCCH
LayerOffset
BTS -40 - +40
dBm
0 dBm With this parameter you define
whether the predefined offset margin
is used when evaluating the signal
level of the non-BCCH layer.
nonBCCH
LayerAccessThr
Segment -110 - -47
dBm
-90 With this parameter you define a
threshold value for the estimated
downlink signal level on non-BCCH
layer for a moving MS from BCCH
layer to non-BCCH layer.
nonBCCH
LayerExitThr
Segment -110 - -47
dBm
-95 With this parameter you define a
threshold value for the measured
downlink signal level on non-BCCH
layer for a moving MS from non-
BCCH layer to BCCH layer.
nonBCCH
LayerExitThr: px
Segment 1 - 32 1 With this parameter you define the
total number of the averaged values
of the signal strength downlink
measurements for triggering the
handover.
nonBCCH
LayerExitThr:nx
Segment 1 - 32 1 With this parameter you define the
number of averaged signal strength
downlink measurements for triggering
the handover.
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Q3 BSC MML Object Range Default
value
Description
msTxPwrMaxCCH Segment 5..43 dBm
with 2 dBm
step
33 dBm With this parameter you define the
maximum transmission power an MS
may use when accessing a CCH in
the cell for GSM 900/800 bands.
gprsMsTxpwrMaxC-
CH
Segment 5..43 dBm
with 2 dBm
step
33 dBm With this parameter you define the
maximum transmission power level a
mobile station can use when
accessing a packet control channel in
the cell for GSM 900/800 bands.
msTxPwrMaxCCH1-
x00
Segment For GSM
1800
0...30dBm
with 2 dBmstep
For GSM
1900 0...32
dBm
with 2 dBm
step and 33
dBm
30 dBm With this parameter you define the
maximum transmission power an
MS may use when accessing a CCH
in the cell for GSM 1800/1900 bands.
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Q3 BSC MML Object Range Default
value
Description
gprsMsTxPwrMaxC-
CH1x00
Segment For GSM
1800
0...36dBm
with 2 dBm
step
For GSM
1900 0...32
dBm
with 2 dBm
step and 33
dBm
30 dBm
GPRSNonBCCHRx-
levLower
BTS -110...-47
dBm
-100 dBm With this parameter you define the
threshold when a reallocation to a
better BTS must be made. BTS with
the direct GPRS access BTS option
on is selected. If there are no BTSs
with direct GPRS access BTS set to
on, the BTS with the lowest non
BCCH layer offset is selected.
GPRSNonBCCHRxle-
vUpper
BTS -110...-47
dBm
-95dBm With this parameter you define the
minimum power level the MS has to
receive to allocate resources from the
BTS.
directGPRSac-
cessBts
BTS -40...40 dBm 0 dBm With this parameter you define which
BTSs in the SEG may be used for
GPRS or EGPRS without signal level
measurements. This parameter
defines the signal level compared
to non BCCH layer offset. When thevalue of this parameter is higher
than the value of the parameter non
BCCH layer offset the direct
GPRS access to non BCCH layer
BTS is applied. This is used in
initial channel allocation and
reallocation.
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Q3 BSC MML Object Range Default
value
Description
bsTxPwrMax
(PMAX1)
BTS 0..30 (dB)
with a step
size of 2
MML
default: 0
With this parameter you identify the
maximum transmission power of the
BTS as an attenuation from the peak
power of the TRX. This parameter is
used for frequency bands GSM 800
and GSM 900.
bsTxPwrMax1x00
(PMAX2)
BTS 0..30 (dB)
with a step
size of 2
MML
default: 0
With this parameter you identify the
maximum transmission power of the
BTS as an attenuation from the peak
power of the TRX. This parameter is
used for frequency bands GSM 1800
and GSM 1900.
non BCCH layer access threshold
(LAR)
The exception is when the BCCH hasbeen configured to GSM 1900 band in
GSM800/GSM1900 Common BCCH
cell. In that case you define a
threshold value for the downlink
signal level on GSM 1900 layer for
allowing access to GSM 1900 BCCH
layer.
non BCCH layer exit
threshold (LER)
The exception is when the BCCH has
been configured to GSM 1900 band in
GSM800/GSM1900 Common BCCH
cell. In that case you define a
threshold value for the measured
downlink signal level on GSM 1900
layer for a moving MS from GSM
1900 BCCH layer to GSM 800 layer.
non-BCCHLayerOffset
The nonBCCHLayerOffset parameter is the key parameter of the Common
BCCH feature. It is set at BTS level and for each BTS it defines the signal level
difference with respect to the BTS carrying the BCCH channel. In order to
optimise the channel allocation procedure in a multi band segment, a self-
regulation procedure is implemented in such a way that the network automatically
tunes the nonBCCHLayerOffset value for each BTS within a segment.
2.5 Impact on NSS
No impact.
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2.6 Impact on OSS
NetAct support for Common BCCH and Multi BCF features is available in
OSS3.1 ED1 onwards. If this release is not available, it is not recommended toactivate Common BCCH and Multi BCF features in the network. In case features
are activated before OSS3.1 ED1 (or later) is installed, the whole management of
radio network in the sites where Common BCCH and Multi BCF are available,
will not work.
Unified Mediation and Adaptation layer interfaces the managed network and
provides data for the network wide systems. BSS adaptation is based on Q3.
NetAct Radio Access Configurator (RAC)
NetAct Radio Access Configurator (RAC) provides network wide access andtools to configure Common BCCH and Multi BCF features. The related BTS
radio parameters can be managed from NetAct Radio Access Configurator from
OSS3.1 ED1 onwards. In BSC the Common BCCH and Multi BCF management
is handled via Segment. In Radio Access Configurator the segment management
is done using a master BTS definition. For more information, see the NetAct
customer document Maintaining Multi-BCF Sites.
NetAct Administrator
NetAct Administrator offers full support to Common BCCH and Multi BCF
admin tasks, for example:
. Fast download and activation of Common BCCH and Multi BCF SW to
BTSs via Nokia NetAct tools
. Expandable SW archives
. Storages for multiple SW configurations
NetAct Planner
Nokia NetAct Planner release 4.1 includes a set of radio network and planning
feature for Common BCCH and Multi BCF. This allows visibility of Common
BCCH and Multi BCF in radio network planning: creation of Multi BCF master BTSs and Common BCCH allocations. Plans can be completed with Radio
Access Configurator.
NetAct Monitor
Standard Nokia NetAct monitoring applications are used also for monitoring of
Common BCCH and Multi BCF features. All alarms are available in NetAct
monitoring tools.
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Reporting for Common BCCH and Multi BCF is done by common Nokia NetAct
reporting tools. Network Doctor utilizes segment as a new measurement object.
Segment replaces in many cases BTSs in reporting:
. Presenting raw counters or KPIs result in Segment_ID level instead of BTS
level with the current ReportBuilder
. Defining the object (for example, segment ID, BTS, etc.) aggregation
method on top of the time aggregation formula in the Formula wizard with
ReportBuilder
. Selecting the Segment ID as hierarchy and Segment ID as summary level
in the dimension selection for report properties
Note that BTS level is still applicable in some cases, although it is in many cases
replaced by segment.
There are also a few new counters in current measurements like HO
measurement. These counters can be seen in Network Doctor report 151:
. Intra Segment success in SDCCH HOs
. Intra Segment success in TCH HOs
. Inter Segment success in SDCCH HOs
. Inter Segment success in TCH HOs
Network Doctor for BSS (optional feature) in ED2 (Network Doctor version3.1.5) utilises segments and the following reports are supported:
. Segment configuration report, 052.
For detailed information on these reports, see NetAct customer document BSS
Network Doctor Reports.
NetAct Tracing
Nokia NetAct Tracing supports Common BCCH and Multi BCF capable Nokia
network elements in OSS3.1 ED1 onwards. TraceViewer offers efficient means totrace mobile equipments or subscribers in GSM and GPRS networks.
TraceViewer does not show any specific counters related to Common BCCH.
Features include real-time troubleshooting and a possibility to monitor the
network functionality and possble problems on a call level. Segment information
is available in Trace reports.
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NetAct Optimizer
Optimizer supports BSS Common BCCH and Multi BCF features. Internally
Optimizer creates Cell objects based on Segment ID and Master BTS flag
information. In geographical map view Common BCCH and Multi BCF Cells
(Segments) are visible entirely; non-segment BTSs are available as earlier. Two
views are available in Topology view: new cell (segment) view and old common
object model view (BSC-BCF-BTS). Adjacency, Power Control and HandOver
Control objects are linked to Master BTS in Cell (Segment).
2.7 Impact on Interfaces
2.7.1 Impact on A Interface
Table 7. This table indicates the impact on the A interface.
Network element Impact
BSC No impact
MSC No impact
2.7.2 Impact on Abis Interface
Network element Impact
BTS No impact
BSC No impact
2.7.3 Impact on Gb Interface
Network element Impact
BTS No impact
BSC No impact
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2.8 Feature Interoperability
Queuing
Queuing is applied at the segment level. There is no priority between different
mobile types; therefore the mobiles supporting all frequency bands are more
likely to be allocated a channel.
There is no specific reason to vary the values of the parameters
timeLimitCall and timeLimitHandover with respect to the one-layer
network setting.
The value of the parameter maxQueueLength has to be re-setting, considering
that the percentage is evaluated on the total number of TRXs (including all BTSs
of the segment) and the resulting number should be lower than the number of available SDCCH channels on the BCCH serving layer band. This is because
some capacity must be left to services that run on SDCCH only (for example,
SMS).
Some mobiles may be put into a queue even though all the TCH resources of the
segment are not fully utilised (this is the case when the mobile in the queue does
not support the available capacity). In this case it is very important to make sure
that SDCCH capacity is still available for further requests from mobiles
supporting the available TCH capacity. For this reason the margin between
maxQueueLength and the number of SDCCH channels on the BCCH serving
layer band should be greater than before.
(E)GPRS
Each BTS object in a segment has its own GPRS terrritory. The parameters that
are used to define the size of GPRS territory are adjusted in each BTS.
When comparing the TCH load of a segment's BTS with the parameter
BTSLoadInSEG the BSC interpretes RTSLs in GPRS territory as busy channels
(excluding dedicated GPRS resources). This interpretation prevents the GPRS
territory of a single BTS from shrinking unnecessarily, if there are other BTSs in
the segment to which CS calls could be transferred from the BTS in question.
Every GPRS BTS in a segment has to be connected to the same PCU.
For more information about GPRS territories, see GPRS in BSC .
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Pre-emption
When the segment architecture is used, Pre-emption is a segment level function.
As in queuing, a pre-emption procedure can occur even though all the TCH
resources of the segment are not fully utilised (this is the case when the mobile
causing a pre-emption does not support the available capacity). The candidate for
forced actions is selected from among the resource types that are supported by the
mobile that initiates the pre-emption procedure. The candidate with the lowest
priority is selected inside the selected frequency bands. Whenever possible, the
BTSs that use the same frequency band as BCCH-BTS are the most preferred
ones. The maximum number of possible calls in a pre-emption queue is 8.
IUO
In the segment environment, the use of Intelligent Underlay-Overlay is a BTS-
specific functionality. Each BTS in a segment can have its own regular and super-reuse layers. The super-reuse layer of a BTS can be accessed only via the regular
layer of the BTS.
Figure 3. IUO frequency groups in GSM900 /GSM1800 Common BCCH
network
Figure 4. IUO frequency groups in GSM800/GSM1900 Common BCCH
network
P reg P super E reg E super D reg D super
P GSM 900 super E GSM 900 super GSM 1800 super
regular TRXs TRXs regular TRXs TRXs regular TRXs TRXs
GSM 800
regular TRXsGSM 800
super TRXs
GSM 1900
regular TRXsGSM 1900
super TRXs
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The target for a super-reuse TCH request is always one BTS (a few TRXs within
the BTS) and not the whole segment as in resource requests in general. The
handover from regular resources to super-reuse resources in a BTS is the same
regardless of whether segment architecture is used or not.
When an IUO handover from a super-reuse TRX to the regular resources of a
BTS is performed, the information on the usability of different resource types in
the segment is decided based on the values of the parameter
nonBCCHLayerOffset in the different BTSs of the segment. As a target, the
BSC accepts the BTSs whose nonBCCHLayerOffset value is less than or
equal to the value of the BTS where the handover was initiated. This is indicated
in the figure Possible handover directions on a segment with dashed-line arrows
going from the super-reuse layer of one BTS to the regular layer of another BTS
in a segment.
The child cell concept is not supported in the BSC in which the segment option isenabled.
Direct Access to super re-use layer is only supported inside the BTS_Object with
the initial SDCCH, which must be in the BCCH band.
To get an accurate estimation of the C/I value of the Common BCCH segment's
non-BCCH frequency band layer, the estimation is based on the measurement of
the BCCH frequency in the segment. The C/I calculation is modified so that the
segment's BCCH measurement result is used instead of the serving TCH
measurement result.
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Figure 5. Possible handover directions on a segment
Multi BCF
If the Multi BCF feature is activated with the Common BCCH Control feature,you can configure not only BTSs that use different frequency bands but also
BTSs of different base station types (for example, Talk-family and UltraSite)
within a segment.
Note
This feature requires synchronisation between the cabinets.
For more information, see Overview of implementing Multi BCF in Multi BCF
System Feature Description.
Frequency Hopping
Frequency Hopping is managed at the BTS level.
BTS1
Regular area
Super reuse area
BTS2
Regular area
Super reuse area
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The MA list is a band-specific list formed according to the frequency band the
MS is directed to and it is indicated to the MS in the Assignment Command and
in the Handover Command. The Immediate Assignment Command always
includes the MA list of the band on which the segment's BCCH resides.
The CA list is used by MSs to decode Mobile Allocation when frequency
hopping is applied. The broadcast of the CA list to the MSs in the System
Information 1 message only includes the segment's frequencies of the band on
which the BCCH carrier resides. PGSM 900 and EGSM 900 are regarded as
separate frequency bands.
Frequency hopping between different bands of operation is not supported.
Frequencies belonging to different bands used in the same segment are kept apart
from each other by having separate Cell Allocation and Mobile Allocation lists
for each frequency band of the segment.
Baseband hopping is not recommended for any number of TRXs, it is only
recommended in BTS_Object ('sector' in the BTS) that have RTC combiners. For
combinerless sectors and sectors with Wideband combiners Radio Frequency
Hopping or Antenna hopping (available with UltraSite in CX4 / BSS11)
baseband hopping is recommended.
Several hopping groups can be assigned even though there are only resources for
one band in a segment. The hopping groups are formed by grouping the needed
TRXs into one BTS and by having several BTSs of the same band. Each BTS has
hopping parameters of its own: different frequency groups can have, for example,
different MA list lengths and different reuses, and thus different hopping gain.This can be used, for example, to have some good quality TRXs and others with
lower quality within a segment. The idea is that the poorer quality TRXs are only
used to handle high traffic peaks.
ICE+
ICE+ is possible as it was in BSS9 in a segment that consists of only one BTS
object. If it is used in the BCCH BTS_Object of a Common BCCH segment with
several BTS objects, then the direct access functionality of ICE+ is only
supported inside the BTS_Object with the initial SDCCH, which must be in the
BCCH band. ICE+ in a non-BCCH BTS_Object is not supported.
When the Common BCCH feature is active, the
nonBCCHLayerAccessThreshold parameter in the Handover Control
Parameter Handling command group is used for the usability evaluation of the
non-BCCH layer in a segment with resources from different frequency bands. For
this reason, theIntelligent Coverage Enhancement features cannot be used in a
segment with BTSs from both GSM 900/800 and GSM 1800/1900 frequency
bands.
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Extended Cell
Extended Cell in UltraSite is a BSS 11.5, CX4.1 feature; it is not a BSS11 feature.
Extended Cell is available for Talk family.
In a segment environment, only BCCH BTSs can have extended area TRXs. If a
segment has resources from different frequency bands, calls can only be handed
over to a band other than the BCCH serving layer in the normal area. If different
bands are present in the segment, quite a balanced capacity distribution between
normal and extended areas can be obtained by configuring almost all TRXs
belonging to the BCCH BTS as extended.
Directed Retry
As in Queuing, also the Directed Retry or the Intelligent Directed Retry
procedure can be triggered even if all resources of a segment are not completelyin use. Since the Directed Retry procedure reduces SDCCH capacity, the Directed
Retry timers should not be set too high and SDCCH capacity should be
dimensioned with the proper margin, to avoid SDCCH blocking (due to the DR
procedure) for any mobile supporting the available TCH capacity.
DADL/B
The purpose of the Direct Access to Desired Layer/Band feature is to direct traffic
in the call setup phase from the SDCCH of a macro cell/GSM 900/800 cell to a
TCH of a micro cell/GSM 1800/1900 cell whenever possible.
In the segment environment, the DADL/B feature can be used to direct traffic
between segments. The loads are evaluated per segment, adjacency definitions
are between segments, and DADL/B handovers are made between segments. The
feature activation therefore only makes sense in the case of a single-band segment
environment.
AMH
The BSC-controlled traffic-reason handover is a segment level procedure which
includes the related parameters. The loads are evaluated per segment, and the idea
is that the power budget margin is dynamically changed to direct the MSs
hanging around on the segment border to less loaded adjacent segments.
Nevertheless, if each segment is dimensioned to handle the needed capacity (as it
should be with the Common BCCH feature, considering that 3 different bands
can be used and up to 36 TRX objects are allowed in a segment), the traffic
should be smoothed out among the BTSs within a segment, rather than directed to
adjacent segments. Therefore, when the Common BCCH feature is active and the
segments are multi-band, the AMH feature is less beneficial.
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Dynamic Hot Spot
The Dynamic Hot Spot control operates on the BTS level. The usability of a
given frequency band is defined by examining the interference of the respective
band in the neighbouring cells. Here PGSM 900 and EGSM 900 are regarded as
one GSM 900 band and the examinations are made accordingly. The dynamic hot
spot algorithm is applied when the number of busy TSLs in the layer where TCH
is requested exceeds the threshold parameter softBlockingStartReg.
Since adjacencies are defined on the segment level, the interfered cells are also
defined at the segment level: all the possible BTSs of an adjacent segment are
examined (layer by layer) if the segment has been defined as an interfered cell.
For the feature to work properly, frequency-hopping groups must be allocated
using the same criteria for all frequency bands. This means that all the layers of a
given segment are interfered by the corresponding layers of the interfering
segment. In the soft blocking evaluation, the contributions from BTSs belongingto the same band are summed up and if different frequency groups are assigned to
BTSs belonging to the same band and same segment, frequency groups should be
assigned in all the interfered segments.
A non-uniform network where one-band segments exist together with multi-band
segments does not affect the performance of the feature.
Dynamic Hot Spot is applied in call attempts and incoming inter-BTSs handovers
(external, internal inter and intra segment), except when TCH is allocated inside a
non-hopping TRX or an internal inter-segment handover is performed because of
bad signal quality.
Minimum acceptable C/N ratio in channel allocation
If the value of the parameter CNThreshold varies between the BTSs of the
same resource type, the BSC selects the highest value for calculation. The
recommendation for a certain resource type in the segment is disabled when the
value is not used even in one of the BTSs of the same resource type.
MS power level optimisation in handover and call setup
If the value of the parameter optimumRxLevUL varies between the TRXs of the
BTSs of the same resource type, the BSC selects the highest value for calculation.The optimum uplink RF signal level for a certain resource type in the segment is
disabled when the value is not used even in one of the TRXs of the BTSs of the
same resource type.
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FACCH Call Setup
FACCH Call Setup means allocating a TCH for the signalling phase of a call in a
SDCCH congestion. Thus, the same restrictions apply for FACCH Call Setup as
for SDCCH allocation: it is limited in the BCCH frequency band.
TRX prioritisation in TCH allocation
The possibility to favour or avoid the BCCH TRX in call assigning has been
maintained to some extent in the segment environment. This is examined after the
BTSs of a segment have been compared on the basis of their loads and their
respective load parameters.
HSCSD
Adding a new frequency band combination into the Common BCCH Controlfunctionality is perfectly transparent from the point of view of the High Speed
Circuit Switched Data feature.
The main change concerning HSCSD is that HSCSD resource allocation is made
according to the capabilities of an MS considering the radio conditions and the
loads of the different resource types. Among the BTSs that the BSC defines as
reasonable, the TCH search is performed so that the HSCSD channel
configuration that best fulfills the request is selected.
The HSCSD feature is BTS-specific.
Shutdown with forced handover
When locking a single BTS of a segment, an intra-cell handover is possible. If a
BCCH-BTS of the segment is in the state locked when another BTS in the SEG is
shut down, only an inter-cell handover is possible. The same applies when the
BCCH-BTS itself is shutting down.
Dual Band
Note
Common BCCH replaces the Dual Band. Dual Band is replaced by Common
BCCH, but is still available for cases where BTS Site & Cell definitions still use
separate BCCHs for each of the bands. Use Common BCCH if possible.
Common BCCH has requirements that have to be taken into account. For
example that the BTS objects of different frequency bands that are combined
within a common BCCH controlled segment have to be co-sited and
synchronised.
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2.9 Impact on mobile terminals
Common BCCH requires a multi band capable terminal.
Common BCCH and handover
Common BCCH and channel allocation
SDCCH dimensioning with Common BCCH
Overview of implementing Common BCCH
Overview of GSM/EDGE Common BCCH
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3 Planning Common BCCH
3.1 Common BCCH and handover
In a Common BCCH segment environment, new types of handovers have been
introduced. Also, handovers between different BTSs can occur inside the samesegment or between different segments. The following handover types have been
added:
. Intra-BTS (intra-segment) handover; equivalent to the old intra-cell
handover
. Inter-BTS intra-segment handover
. Inter-segment internal (intra-BSC) handover
. Inter-segment external (inter-BSC) handover; equivalent to the old external
handover
The inter-BTS handovers can occur within the same frequency layer or between
different frequency layers.
Handover causes
. Power Budget Handover
The standard PBGT (power budget) calculation is applied for an MS on the
PGSM 900, EGSM 900, or GSM 800 layer. If an MS is on the GSM 1800/
1900 layer of the multi band Common BCCH segment, the decision on the
PBGT handover is based on the measurement of the segment's own BCCH
frequency that the MS measures when on the GSM 1800 band. The BCCH
measurements are compared with each other to decide the superiority
between the serving and an adjacent segment.
. Load based TCH handover
In addition to the standard TCH TCH handovers, when the Common
BCCH is active, the BSC can command an additional handover to balance
the load between different frequency bands.
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During the call setup procedure the load cannot necessarily be kept under
the BTSLoadInSEG limit for each BTS, because not all terminals support
all the resource types. Furthermore, due to their propagation properties, the
GSM 1800/1900 resources may not be available in all TCH allocation
cases.
When deciding on initiating a handover to balance the load between the
BTSs of a segment, the triggering load limit L is defined with the formula:
L = BTSLoadInSEG + ((100 - BTSLoadInSEG )/2)
Even if the BTSLoadInSEG-parameter has been set to value 0, load in the
BCCH BTS has to be over 50% in order to calls are moved to the other
BTS of non BCCH layer. If the BTSLoadInSEG-parameter is set to value
1%..100%, current way of calculation of load limit is used.
Using the adjusted value of BTSLoadInSEG -parameter as a triggeringload limit for handover within segment has changed after loading CD3.0
for 13.13-0 environment. This has an impact on cases where resources on
the BCCH-layer are scarce.
As an improvement, the possibility to trigger an intra cell handover from
the BCCH layer BTS irrespective of the load in the BTS has been
implemented. The value 0 of BTSLoadInSEG-parameter has now a special
meaning. When the operator has set it to value 0, the BSC tries to hand all
calls fullfilling signal strength criterias over from the BCCH layer BTS to
non BCCH layer. This causes that the resources on the BCCH layer are
kept free as far as possible.
Since in GSM900/GSM1800 the main purpose of the handover is to move
the TCH load from the GSM 900 bands to the GSM 1800 band and EGSM
band, respectively, these two bands are the only possible targets (with
priority given to the 1800 band).
In GSM 800/1900, it may be preferable to use a handover that moves the
TCH load from the GSM 1900 band to the GSM 800 band instead of
freeing the TCH for a single-band GSM 1900 mobile.
The BSC checks the load of the GSM 900/800 BTS every time it receives a
TCH request for the segment in question. When the BSC selects target
BTSs for a load based intra cell handover, it only accepts BTSs whose load
is below the respective BTSLoadInSEGvalue.
SDCCH handover
In addition to the standard SDCCH SDCCH handovers, a new inter band (intra-
segment) SDCCH handover has been implemented to avoid long SDCCH
reservations, thus reducing the SDCCH pressure on the BCCH resource layer.
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This handover is triggered when the length of an SDCCH reservation on the
BCCH layer equals the value of the intraSegSDCCHHoGuard parameter.
The handover is performed if there are available SDCCH resources outside the
BCCH band and the MS has the required capability.
Overview of GSM/EDGE Common BCCH
3.2 Common BCCH and channel allocation
SDCCH allocation procedure
The general process of SDCCH selection (that applies in the case of an SDCCH-
SDCCH intra-BSC handover) is the following:
. BTS selection:
The BTSs where the SDCCH can be allocated are filtered based on the
information on the frequency capability of the accessing MS and on the
usability of radio resources in different frequency bands.
The BTSs are divided into groups according to their frequency band (BTSs
using the BCCH frequency band form one group and BTSs using a
frequency other than the BCCH frequency band form another group).
The SDCCH load of each BTS group is calculated taking into account only
the static SDCCH resources. The channel is allocated from the BTS group
that has the lowest load.
. TRX selection:
Within the selected BTS(s), the TRX that has the lowest channel load
(busy traffic and signalling channels) is selected. In RF hopping , the BTSs
with an RF hopping TRX prioritisation, the priority is given to non-BCCH
TRXs. The SDCCH channel from the BCCH TRX is allocated only if there
are no idle SDCCHs in other TRXs at all.
. RTSL selection:
The RTSL that has the highest number of idle SDCCH channels left is
selected. However, if a signalling channel was last allocated from the same
TRX, another RTSL than last time is allocated, when possible.
If there are no idle static SDCCH resources in the BTSs, dynamic SDCCH
resources are searched for in every BTS group. From all TRXs, the RTSL
which has the least idle dynamic SDCCH channels is selected.
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SDCCH assignment (Immediate Assignment)
In a multi-band Common BCCH segment, the initial SDCCH channel for a call
setup is always allocated in the layer where the segment's BCCH resides.
This is because the capabilities of an accessing MS are not known when the MS
sends the establish indication message. It is not possible to define the usability of
the non-BCCH frequencies of the segment, as the MS only starts sending
measurement reports after it has been moved to a dedicated channel.
Within the BCCH frequency band, the SDCCH to be allocated is selected
according to the algorithm described above.
If there are no idle static or dynamic SDCCH resources in the BTSs, an idle TCH
timeslot is configured as a new temporary SDCCH resource. Dynamic SDCCH
reconfiguration is only applied in the Immediate Assignment phase, not inhandovers.
SDCCH external handover
During inter-BSC handovers, the usability of radio resources in different
frequency bands than the BCCH cannot be defined in the target BSC. If the non-
BCCH layer is regarded as a layer with less coverage (as indicated by the positive
value of the nonBCCHLayerOffset parameter), only BCCH frequency band
resources are used in the SDCCH allocation for an external handover. (If the
BCCH is on GSM 900/800, the EGSM 900 band can also be utilised according to
the MS capabilities.) If the non-BCCH layer is regarded as a layer with morecoverage (as indicated by the negative value of thenonBCCHLayerOffset
parameter), the non-BCCH layer resources can also be used in the SDCCH
allocation for an external handover according to the mobile capabilities.
SDCCH-SDCCH intra-BTS handover
In the case of an intra-BTS handover, the SDCCH allocation differs from the
basic procedure. The SDCCH is trying to be allocated in a TRX other than the
call serving TRX. The channel in the call-serving RTSL is never selected
(therefore the search procedure is started only if a SDCCH RTSL other than the
serving one is defined in the BTS). If the call-serving TRX is blocked, the basic
search procedure is used.
TCH assignment
The basic difference between TCH allocation in a Common BCCH controlled
segment and a single BTS cell is that the target of a TCH request in a segment is a
set of BTSs instead a single BTS. Basically, all existing rules for selecting a TCH
in a single BTS cell are also valid between BTSs in a segment cell. The general
process for TCH selection is as follows:
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. BTS(s) selection:
The BTSs where a TCH can be allocated are filtered on the basis of the
information on the frequency capability of the accessing MS and on the
usability of radio resources in different frequency bands.
The BTSs are filtered according to their load. The load calculation is based
on the BTS-specific parameter BTSLoadInSEG. TCHs are assigned from
the BTSs whose load is less than the BTSLoadInSEG value. See chapter
Handover causes.
When each BTS has reached its load limit the allocation continues in those
BTSs where the load is less than the highest load threshold value among
the BTSs.
When the load in all the BTSs has reached the level of the highest load
threshold value among the BTSs, the GSM 1800 band, the EGSM 900, and
PGSM 900 bands are respectively preferred. Therefore the prioritisation
between the frequency layers is applied only in high-load conditions,
where the better GSM 900 resources are saved for the MSs with limited
frequency capability or in the cell border area.
. RTSL(s) selection:
After the primary target group of BTSs for TCH allocation has been
selected, all the idle RTSLs are ranked according to their interference level
and to the interference level recommendation defined in the BTS they
belong to.
If there are several candidate RTLSs with the same interference level, the
TRX prioritisation in TCH allocation is applied: the RTSL is allocated
from the BCCH TRX or from a non-BCCH TRX according to the defined
prioritisation.
If several candidate RTLSs exist after applying the TRX prioritisation in
TCH allocation, the RTSL is allocated from the BTS with the lowest
Circuit Switched load by using the round robin method so that the BTS
allocated the previous time is the last choice.
Overview of GSM/EDGE Common BCCH
3.3 SDCCH dimensioning with Common BCCH
Consider the multi-band mobile and the following two scenarios:
Case 1: GSM Network with separated cells GSM 900/800 and GSM 1800/1900
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Case 2: Common BCCH GSM Network (GSM 900/800 and GSM 1800/1900
BTSs co-located).
Case 1 Case 2
. 2 TRXs/cell (1% blocking), 8.11 Erl/cell
. Traffic density 25 mErl/subs, 325 subs/cell
. Call establishment time:
SDCCH reservation time 7 sec/call, 1.94 mErl/call,
325 calls/hour/cell x 1.94 mErl/call = 0.631 Erl/cell
(SDCCH)
. Location update (once in 60 minutes), 325 subs/
cell x 1.94 mErl/call = 0.631 Erl/cell (SDCCH)
. SDCCH capacity = 0.631 + 0.631 =1.262 Erl/cell
.
Number of SDCCH channels/cell = 55 SDCCH channels are necessary for each BTS. So a
separated channel configuration is needed for each
BTS (TS0 is dedicated for the BCCH channel and TS
1 for SDCCH channels).
. 4 TRXs in a segment (1% blocking), 20.33 Erl/cell
. Traffic density 25 mErl/subs, 813 subs/cell
. Call establishment time:
SDCCH reservation time 7 sec/call, 1.94 mErl/call,
813 calls/hour/cell x 1.94 mErl/call = 1.58 Erl/Call
(SDCCH)
. Location update (1.4 times in 60 minutes due to
smaller location area compare with 2 TRXs/cell),
813 calls/cell x 1.4 x 1.94 mErl/call = 2.2 Erl/Cell
(SDCCH)
. SDCCH capacity = 1.58 Erl/Cell + 2.2 Erl/Cell = 3.8
Erl/Cell
Number of SDCCH channels = 10. A separated
configuration is needed, with 2 TS for SDCCH on the
BCCH layer.
Overview of GSM/EDGE Common BCCH
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4 Implementing Common BCCH
4.1 Overview of implementing Common BCCH
Summary
Common BCCH feature is always active if the operator has bought it. It cannot be
activated/disabled with the WOA command.
The following implementation instructions of Common BCCH in Nokia network
are for GSM800 and GSM1900. The same procedure can be applied to
implement other band combinations.
Steps
1. Creating a multiband cell (segment)
2. Moving a BTS from one segment to another existing segment
3. Cancelling the expand of the segment
Further information
. Overview of GSM/EDGE Common BCCH .
. SDCCH dimensioning with Common BCCH .
. NetAct documentation set: Implementing Parameter Plans gives
instructions on how to plan and prepare parameter changes, for example
when bringing new features into use in the GSM and WCDMA networks.
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4.2 Creating a multiband cell (segment)
Purpose
Create a multiband segment by creating a new GSM 800 BTS to an existing GSM
1900 segment.
Before you start
The preconditions for a multiband segment creation are that the existing segment
has one BTS using the GSM 1900 frequency band that has all TRXs in the WO
state. During the BSC software installation, the system has created a SEG for
each existing BTS. The number of the SEG is the same as the number of the
related BTS, for example BTS-12 => SEG-12.
You can use the create BTS and TRX commands of the BSC MML or NetAct to
create the new BTS.
Steps
1. Create a BTS
a. Create a BTS which uses the GSM 800 frequency band.
With the EEI command you get information about all BTSs and
TRXs of the SEG
EEI:SEG=<seg_id>;
b. Create a BTS (GSM 800) to a segment that has one BTS using the
GSM 1900 frequency band.
Note
Because the segment already exists, the MML does not allow the user to define
cell (segment) specific parameters. Only BTS-specific parameters are allowed.
EQC:BCF=<bcf_id>,BTS=<bts_id>,SEG=<seg_id>:
BAND=800;
c. Check the information about all TRXs of the SEG..
By using the EEI command, you can check the information about all
TRXs of the SEG
EEI:SEG=<seg_id>;
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Examples:
a. ZEEI:SEG=44;
SEG-44:
B C F- 0 44 U L TR A S I TE
B T S- 0 44 (G S M 1 9 00 )
T R X - 0 01 (M B C C H C)
TRX-002
b. ZEQC:BCF=44,BTS=77,SEG=44:BAND=800;
c. ZEEI:SEG=44;
SEG-44:
B C F- 0 44 U L TR A S I TE
B T S- 0 44 (G S M 1 9 00 )
T R X - 0 01 (M B C C H C)
TRX-002
B T S- 0 77 (G S M 8 0 0)
2. Delete the old BCCH channel
Delete the BCCH channel from the BTS using the GSM 1900 frequency
band.
a. Lock the BTS that uses the GSM 1900 frequency band
EQS:BTS=<bts_id>:L;
b. Lock the BCCH TRX
ERS:BTS=<bts_id>,TRX=<trx_id>:L;
c. Delete the BCCH channel of the BTS and modify it to a TCH
channel
ERM:BTS=<bts_id>,TRX=<trx_id>:CH0=TCHF;
Examples:
a. ZEQS:BTS=44:L;
b. ZERS:BTS=44,TRX=1:L;
c. ZERM:BTS=44,TRX=1:CH0=TCHF;
3. Create a TRX and the BCCH channel
Create a transceiver (TRX) for the new BTS using the GSM 800 frequency
band. Create the BCCH channel.
a. Create the BCCH TRX
ERC:BTS=<bts_id>,TRX=<trx_id>:FREQ=<freq>,
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TSC=<nbr>,PCMTSL=<pcm-tsl>:DNBR=<nbr>:CH0=MBCCHC;
b. Check the information about all TRXs of the SEG
EEI:SEG=<seg_id>;
Examples:
a. ZERC:BTS=77,TRX=3::FREQ=130,TSC=1,PCMTSL=40-1:
DNBR=114:CH0=MBCCHC;
b. ZEEI:SEG=44;
B C F- 0 44 U L TR A S I TE
B T S- 0 44 (G S M 1 9 00 )
TRX-001
TRX-002
B T S- 0 77 (G S M 8 0 0)
T R X - 0 03 (M B C C H C)
4. Modify the parameter MsTxpwrMaxGSM(PMAX1) for the new BTS
using the GSM 800 band
Skip this procedure if the default value of the parameter PMAX1 (the
maximum power level that an MS may use in the serving cell) is good
enough.
a. Output BTS parameters
EQO:SEG=<seg_id>:MIS;
b. Modify the MSTxpwrMaxGSM(PMAX1) parameter of the BTS
EQM:SEG=<seg_id>:PMAX1=<value>;
Examples:
a. ZEQO:SEG=77:MIS;
b. ZEQM:SEG=77:PMAX1=35;
5. Define the maximum transmission power for MS accessing the cell
The maximum transmission power that an MS may use when accessing the
BCCH or PCCCH of a cell in which the BCCH is on the GSM 800
frequency band is defined with the parameters MsTxpwrMaxCCH(TXP1)
and GPRSMsTxpwrMaxCCH (GTXP1). The default value for both
parameters is 33 dBm. You can skip this procedure if the default value is
applicable for both parameters.
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Note
You can only modify the parameters via segment identification if the segment has
more than one BTS.
Modify the TXP and GTXP of the segment
Modify the MsTxpwrMaxCCH (TXP1) and GPRSMsTxpwrMaxCCH
(GTXP1) parameters.
EQG:SEG=<seg_id>:TXP1=<value>,GTXP1=<value>
Example:
ZEQG:SEG=44:TXP1=35,GTXP1=31;
6. Modify the power control parameters of the segment
Skip this procedure if the power control parameters of the BTS using the
GSM 1900 band values are also applicable to the new BTS using the GSM
800 frequency band. Check that the GSM 800 / GSM 900 frequency band
specific power control parameter bs tx pwr max (PMAX1) has an
applicable value. If not, modify the power control parameters of the
segment.
Note
You can modify the power control parameters only via segment identification if
the segment has more than one BTS. The new value is set for all BTSs of the
segment.
a. Output the power control parameters
EUO:SEG=<seg_id>;
b. Modify the power control parameters
Modify the PMAX (bs txpwr max) parameter.
EUG:SEG=<seg_id>:PMAX1=<value>;
Examples:
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a. ZEUO:SEG=44;
b. ZEUG:SEG=44:PMAX1=10;
7. Define the signal level difference by using the parameternonBCCHLayerOffset
Define the signal level difference between a BTS without the BCCH TRX
and the BCCH BTS of the segment.
Modify the value of the nonBCCHLayerOffset parameter. When
creating a BTS, the default value is 0 dBm.
EQM:BTS=<bts_id>:NBL=<value>;
Example:
ZEQM:BTS=44:NBL=5;
Note
Parameters BS TX pwr max (PMAX) and BS TX pwr max 1x00 (PMAX2)
identify the maximum transmission power of the BTS as an attenuation from the
peak power of the TRX and have to be taken into account when defining the
value for parameter nonBCCHLayerOffset (NBL).
Note
The parameter nonBCCHLayerOffset (NBL) is used to indicate how much
weaker the signal level of a BTS is when compared to that of the BCCH BTS.
Because of this, the value of the parameter must always be set to 0 in the BCCH
BTS. A positive value of the NBL in a BTS indicates a signal level lower than in
the BCCH BTS and prevents the SDCCH allocation for call setups and external
handovers in that BTS.
8. Define the load limit for a BTS
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Define the load limit for a BTS with the parameter LSEG
(BTSLoadInSEG). You can determine separate LSEGs for all BTSs of
the segment. LSEG is used in controlling the load distribution between
different BTSs in a segment. The default value when creating a BTS is
70%. If you want to change it, use the command EQM.
Modify the value of the BTS load in SEG parameter
EQM:BTS=<bts_id>:LSEG=<value>;
Example:
ZEQM:BTS=77:LSEG=50;
9. Define the threshold value for the estimated downlink signal level on
the non-BCCH frequency layer
Define the threshold value for a segment with the parameter
nonBCCHLayerAccessThreshold (LAR).
LAR is a threshold value for the estimated downlink signal level on the
non-BCCH frequency layer of the segment for moving an MS from the
BCCH frequency layer to the non-BCCH frequency layer. The default
value is 90 dBm. If you want to change it, use the command EHS.
Modify the value of the nonBCCHLayerAccessThreshold parameter
EHS:SEG=<seg_id>:LAR=<value>;
Example:
ZEHS:SEG=44:LAR=-80;
10. Define the threshold for handing an MS over from the non-BCCH
frequency layer to the BCCH frequency layer
Define the threshold for a segment with the parameters
nonBCCHLayerExitThreshold (LER) ,nonBCCHLayerExitThresholdpx (LEP), and
nonBCCHLayerExitThresholdnx (LEN).
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LER is a threshold value for the measured downlink signal level on the
non-BCCH frequency layer for handing an MS over from the non-BCCH
frequency layer to the BCCH frequency layer. LEP and LEN can be used
to define how many of the measurement reports must be below the LER to
trigger the handover. The default value for LER is
95 dBm, the default
value for LEP is 1, and the default value for LEN is 1. If you want to
change the values, use the command EHS.
Handover from the non-BCCH frequency layer to the BCCH frequency
layer is made only if the BCCH frequency layer of the segment has more
coverage than the non-BCCH frequency layer. These three parameters are
used by the BSC only when the BCCH frequency layer of the segment has
more coverage than the non-BCCH frequency layer. Otherwise they are
ignored.
Modify the non-BCCHLayerExitThreshold parameters
EHS:SEG=<seg_id>:LER=<values>,LEP=<value>,LEN=<value>;
ZEHS:SEG=44:LER= 90,LEP=3,LEN=5;
11. Modify the power control parameters of the segment
Skip this procedure if the power control parameters of the BTS using the
GSM 1900 band values are also applicable to the new BTS using the GSM
800 frequency band. Check that the GSM 800 / GSM 900 frequency band
specific power control parameter bs tx pwr max (PMAX1) has anapplicable value. If not, modify the power control parameters of the
segment.
Note
You can modify the power control parameters only via segment identification if
the segment has more than one BTS. The new value is set for all BTSs of the
segment.
a. Output the power control parameters
EUO:SEG=<seg_id>;
b. Modify the power control parameters
Modify bs tx pwr max (PMAX1) parameter.
EUG:SEG=<seg_id>:PMAX1=<value>;
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Examples:
a. ZEUO:SEG=44;
b. ZEUG:SEG=44:PMAX1=10;
12. Create adjacent cells
Create more adjacent cell information, if needed. You can create adjacent
cell information with the EAC command, but if the segment has more than
one BTS you have to use segment identification as a parameter instead of
BTS identification.
a. Create an adjacent cell for a segment that has more than one BTS
and is under another BSC
EAC:SEG=<seg_id>::LAC=<nbr>, CI=<nbr>:NCC=<nbr>,
BCC=<nbr>,FREQ=<nbr>;
b. Create an adjacent cell for a segment that has more than one BTS
and is under the same BSC
EAC:SEG=<seg_id>::ASEG=<aseg_id>;
Examples:
a. ZEAC:SEG=44:LAC=199,CI=39:NCC=1,BCC=1,FREQ=131;
b. ZEAC:SEG=44::ASEG=99;
13. Delete an adjacent cell of the segment
In the Common BCCH feature, the BCCH frequency of the segment itself
is added among the BCCH frequencies that the MS should measure when
on the non-BCCH frequency band of the multiband segment. This leads to
the following restriction: a segment can have only 31 adjacent cells.
If the inter-system handover feature is used with the Common BCCH
Control feature then the maximum number of adjacent cells is restricted to
30. Skip this procedure if the segment does not have 32 or 31 adjacent
cells. Otherwise remove one or two adjacent cells of the segment.
Delete the adjacent cell
EAD:SEG=<seg_id>::ASEG=<aseg_id>;
Example:
ZEAD:SEG=44::ASEG=88;
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14. Modify the BA list <option>
In the Common BCCHl feature, the BCCH frequency of the segment itself
is added among the BCCH frequencies that the MS should measure when
the Common BCCH feature is activated. This leads to the following
restriction: there can be only 31 frequencies in a BA list.
If the Inter-System Handover feature is used with the Common BCCH
feature, the maximum number of frequencies in a BA list is restricted to 30.
Skip this procedure if the BA list is not used or if the BA list does not have
32 or 31 BCCH frequencies. Otherwise remove one or two BCCH
frequencies from the BA list (BCCH frequency list).
a. Output the BA list usage parameters
EQO:SEG=<seg_id>:BCC;
b. Remove one BCCH frequency from the BA-list
EBM:<id_nbr>,<function>:<freq>;
Examples:
a. ZEQO:SEG=44:BCC;
b. ZEBM:15,R:140;
15. Create a BA list and attach it to a segment <option>
Skip this procedure if BA lists (BCCH frequency lists) are not used.
a. Create a BA list
Note
If this BA list is going to be used for a segment which has more than one
frequency band in use, the type (frequency band) of the BA list must be MULTI.
EBC:<id_nbr>,MULTI:
<frequency>&<frequency>&<frequency>;
b. Attach the BA list to the segment
EQB:SEG=<seg_id>:IDLE=<ba_id>;
Examples:
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a. ZEBC:10,MULTI:150&160&170;
b. ZEQB:SEG=44:IDLE=10;
16. Control the BTS states
The segment object has neither an operational nor an administrative state,
so you must unlock the BTSs of the segment one by one. The BCCH BTS
must be unlocked first. When you unlock a non-BCCH BTS, then the
BCCH TRX of the segment must be in the administrative state WO.
a. Unlock the BCCH TRX
ERS:BTS=<bts_id>,TRX=<trx_id>:U;
b. Unlock the BTS containing the BCCH TRX
EQS:BTS=<bts_id>:U;
c. Unlock the TRXs of the BTS using the GSM 1900 frequency band
ERS:BTS=<bts_id>,TRX=<trx_id>:U;
d. Unlock the BTS using the GSM 1900 frequency band
EQS:BTS=<bts_id>:U;
e. Unlock the BCF
EFS:<bcf_id>:U;
Examples:
a. ZERS:BTS=77,TRX=3:U;
b. ZEQS:BTS=77:U;
c. ZERS:BTS=44,TRX=1:U;
ZERS:BTS=44,TRX=2:U;
d. ZEQS:BTS=44:U;
e. ZEFS:44:U;
17. Check the postcondition
After unlocking, all TRXs of the segment are in the WO state. A call
should be possible via both BTSs. Synchronized handovers are used
between the BTSs. The system has set synchronized handovers on by
default.
Get information about all TRXs of the SEG
With the EEI command you get information about all TRXs of the SEG.
The system outputs both BTSs and all TRXs of the segment.
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EEI:SEG=<seg_id>;
Example:
ZEEI:SEG=44;
Further information
For an overview, see Overview of implementing Common BCCH
4.3 Cancelling the expand of the segment
Purpose
You can move either the BTS using the GSM 800 frequency band or the BTS
using the GSM 1900 frequency band to a new, separate segment. If you want to
move the BTS, which has the BCCH TRX, you must first delete the BCCH
channel because moving a BTS containing a BCCH TRX is not allowed. All
BTSs of the old segment must be in the locked state. For an overview, see
Overview of Common BCCH implementation.
Steps
1. Lock the segment's BTSs and delete its BCCH channel
a. Lock both BTSs and the BCCH TRX
EQS:BTS=<bts_id>:L;
EQS:BTS=<bts_id>:L;
ERS:BTS=<bts_id>,TRX=<trx_id>:L;
b. Delete the BCCH channel and modify it to a TCH channel
ERM:BTS=<bts_id>,TRX<trx_id>:CH0=TCHF;
Examples:
a. ZEQS:BTS=44:L;
ZEQS:BTS=77:L;
ZERS:BTS=77,TRX=3:L;
b. ZERM:BTS=77,TRX=3:CH0=TCHF;
2. Move the BTS using the GSM 800 frequency band to its own segment
Move the BTS to a new segment
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EQU:BTS=<bts_id>:SEG=<seg_id>:CI=<nbr>:NCC=<nbr>,
BCC=<nbr>:MCC=<nbr>,MNC=<nbr>,LC=<nbr>;
For example:
Move base station BTS-77 to segment SEG-88. Segment-specific
parameters must be defined for the new segment.
ZEQU:BTS=77:SEG=88:CI=5:NCC=1,BCC=1:MCC=1,MNC=1,
LAC=15;
3. Define a BCCH TRX for the BTSs using the GSM 1900 and GSM 800
frequency bands
a. Lock a TRX of the BTS using the GSM 1900 frequency band
ERS:BTS=<bts_id>,TRX=<trx_id>:L;
b. Define the BCCH channel to the TRX of the BTS using the GSM
1900 frequency band
ERM:BTS=<bts_id>,TRX=<trx_id>:CH0=MBCCH;
c. Define the BCCH channel to a TRX of the BTS using the GSM 800
frequency band
ERM:BTS=<bts_id>,TRX=<trx_id>:CH0=MBCCH;
Examples:
a. ZERS:BTS=44,TRX=1:L;
b. ZERM:BTS=44,TRX=1:CH0=MBCCHC;
c. ZERM:BTS=77,TRX=3:CH0=MBCCHC;
4. Define the maximum transmission power for an MS accessing the cell
for both segments
The maximum transmission power that an MS may use when accessing the
BCCH or PCCCH of a cell in which the BCCH is on the GSM 1900
frequency band is defined with the parameters MsTxpwrMaxCCH 1x00
(TXP2) and GPRS MsTxpwrMaxCCH 1x00 (GTXP2). The default value for both parameters is 30 dBm.
The maximum transmission power that an MS may use when accessing the
BCCH or PCCCH of a cell in which the BCCH is on the GSM 800
frequency band is defined with the parameters MsTxpwrMaxCCH
(TXP1) and GPRS MsTxpwrMaxCCH (GTXP1). The default value for
both parameters is 33 dBm.
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You can skip this procedure if the default values are applicable for both
segments.
Note
You can modify the parameters only via segment identification if the segment has
more than one BTS.
a. Modify the TXP2 and GTXP2 of the segment in which the BCCH is
on the GSM 1900 frequency band
EQG:SEG=<seg_id>:TXP2=<value>,GTXP2=<value>;
b. Modify the TXP1 and GTXP1 of the segment in which the BCCH ison the GSM 800 frequency band
EQG:SEG=<seg_id>:TXP1=<value>,GTXP1=<value>;
Examples:
a. ZEQG:SEG=44:TXP2=30,GTXP2=30;
b. ZEQG:SEG=88:TXP1=33,GTXP1=33;
5. Define HOC, POC, and ADJ parameters for the BTS that was moved
Modify the power control parameter values and handover control values,
and create adjacent cells for the BTS that was moved. This must be done
because the power control (POC), handover control (HOC), and
adjacencies do not follow the moved BTS to the new segment. You have to
define the POC, HOC, and any adjacencies needed for the new segment
like in BTS creation.
You can now modify the power control and handover control parameters
via segment identification or via BTS identification because the segment
that has the BTS that was moved only has one BTS.
a. Create power control parameters
Create power control parameters for the new segment by using
either SEG or BTS identifier.
EUC:SEG=<seg_id>;
or
EUC:BTS=<bts_id>;
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b. Create handover control parameters
Create handover control parameters for the new segment by using
either the SEG or BTS identifier.
EHC:SEG=<seg_id>;
or
EHC:BTS=<bts_id>;
c. Create an adjacent cell
Create an adjacent cell for the new segment. The adjacent cell is
under the same BSC. You can use either SEG or BTS identifier.
EAC:SEG=<seg_id>::ABTS=<bts_id>;
or
EAC:BTS=<bts_id>::ABTS=<bts_id>;
Examples:
a. ZEUC:SEG=88;
or
ZEUC:BTS=77;
b. ZEHC:SEG=88;
or
ZEHC:BTS=77;c. Create adjacent cell BTS-44 for SEG-88.
ZEAC:SEG=88::ABTS=44;
or
ZEAC:BTS=77::ABTS=44;
6. Control the BTS states
The segment object has neither an operational nor an administrative state,
so you must unlock the BTSs of the segment one by one. The BCCH BTS
must be unlocked first. When you unlock a non-BCCH BTS the BCCHTRX of the segment must be in the administrative state WO.
a. Unlock the BCCH TRX of the BTS that was moved
ERS:BTS=<bts_id>,TRX=<trx_id>:U;
b. Unlock the BTS that was moved
EQS:BTS=<bts_id>:U;
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c. Unlock the BCCH TRX of the BTS using the GSM 1900 frequency
band
ERS:BTS=<bts_id>,TRX=<trx_id>:U;
d. Unlock the BTS using the GSM 1900 frequency band
EQS:BTS=<bts_id>:U;
Examples:
a. ZERS:BTS=77,TRX=3:U;
b. ZEQS:BTS=77:U;
c. ZERS:BTS=44,TRX=1:U;
d. ZEQS:BTS=44:U;
Further information
For an overview, see Overview of implementing Common BCCH
4.4 Moving a BTS from one segment to another existing segment
Purpose
In this case you move a BTS from the old segment to a new existing segment. AllBTSs in the old segment and in the new segment must be in the locked state.
Moving a BTS containing the BCCH TRX is not allowed. The BTS that was
moved starts to use the new segment's parameters. After moving the BTS you
must unlock all BTSs of the old and the new segment.
Note
When you combine two segments together, move all BTSs of one segment to a
new existing segment. After moving all BTSs the old segment does not exist any
more.
Note
TheGPRS has to be disabled in all BTSs in both segments when moving a BTS
from one segment to another.
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Steps
1. Lock all BTSs in the old and the new segment
You are moving a BTS from a segment which has two BTSs to a new
existing segment which has one BTS. The BCCH TRX is not under the
BTS which is going to be moved.
Note
First you must lock all BTSs of both segments.
a. Get information about all BTSs and TRXs of both segments
EEI:SEG=<seg_id>;
EEI:SEG=<seg_id>;
b. Lock all BTSs of the old segment
EQS:BTS=<bts_id>:L;;
EQS:BTS=<bts_id>:L;
c. Lock all BTSs of the new segment
EQS:BTS=<bts_id>;
Examples:
a. ZEEI:SEG=33;
SEG-33:
B C F- 0 33 U L TR A S I TE
B T S- 0 33 (G S M 8 0 0)
T R X - 0 01 (M B C C H C)
TRX-002
B T S- 5 5 (G S M 8 0 0)
TRX-3
ZEEI:SEG=66;
SEG-66:
B C F- 0 66 U L TR A S I TE
B T S- 0 66 (G S M 8 0 0)
T R X - 0 01 (M B C C H C)
TRX-002
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b. ZEQS:BTS=33:L;
ZEQS:BTS=55:L;
c. ZEQS:BTS=66:L;
2. Move the BTS from the old segment to the new existing segment
Move the BTS by using the EQU command.
EQU:BTS=<bts_id>:SEG=<seg_id>;
This is an example:
Move BTS-55 to the new existing segment SEG-66.
ZEQU:BTS=55:SEG=66;
3. Unlock all BTSs in the old and the new segment
a. Unlock the BTS of the old segment
EQS:BTS=<bts_id>:U;
b. Unlock all BTSs of the new segment
Note
You must first unlock the BTS that has the BCCH TRX.
EQS:BTS=<bts_id>:U;
c. Get information about all BTSs and TRXs of both segments
With the EEI command you get information about all BTSs and
TRXs of both segments.
EEI:SEG=<seg_id>;
Examples:
a. ZEQS:BTS=33:U;
b. ZEQS:BTS=66:U;
ZEQS:BTS=55:U;
c. ZEEI:SEG=33;
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SEG-33:
B C F- 0 33 U L TR A S I TE
B T S- 0 33 (G S M 8 0 0)
T R X - 0 01 (M B C C H C)
TRX-002
ZEEI:SEG=66;
SEG-66:
B C F- 0 66 U L TR A S I TE
B T S- 0 66 (G S M 8 0 0)
T R X - 0 01 (M B C C H C)
TRX-002
B T S- 5 5 (G S M 8 0 0)
TRX-3
Further information
For an overview, see Overview of implementing Common BCCH .
Implementing Common BCCH