Common BCCH System Feature

Common BCCH System FeatureDescription

dn03298529Issue 3 en

# Nokia CorporationNokia Proprietary and Confidential

1 (59)

2002546Nokia GSM/EDGE BSS11 SystemDocumentation Set

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, orperformance 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.

2 (59) # Nokia CorporationNokia Proprietary and Confidential


Common BCCH System Feature Description

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 162.3.3 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



3 (59)

Contents




1 Overview of GSM/EDGE Common BCCH

The Common BCCH feature allows the integration of resources from differentfrequency bands into one cell. A common BCCH of a cell is configured in onlyone of the bands of operation when resources across all bands are co-located andsynchronized.



5 (59)

Overview of GSM/EDGE Common BCCH

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 1GSM900 (BCCH) /

GSM1800


GSM1800


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




. EGSM 900 / GSM 1800

. GSM 800 / GSM 1900.

The BCCH carrier is allowed in any of the supported frequency bands, exceptthat the common BCCH is allowed in the EGSM900 frequency band only if thereis 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 frequencyallocation 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 betweenfrequency 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 acell 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:



7 (59)


. 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 sitetype (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 BCCH�s BTS configuration is shown in the figure. Whenconsidering Common BCCH, segment-specific parameters and BTS specificparameters should be taken into account. In many cases, BTS and frequency bandare 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. Segmentspecific, BTS specific and frequency band specific parameters need to beconsidered in this case.

The allocation of a dedicated channel (SDCCH or TCH) inside a multibandsegment (that is, with BTSs from different frequency bands) is based on:

BCF BCF BCF

BTS BTS BTS

PGSM 900

PGSM 900BCCH

EGSM900

GSM 1800

SEGMENT

Segment specificparameters

BTS specific parameters




. 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 newBTS parameter, nonBCCHLayerOffset.

Mobile frequency capability

Different classes of mobiles can be defined according to their frequencycapabilities.

The information of the frequency capabilities of the mobile station is included inthe Mobile Station Classmark 2 and Mobile Station Classmark 3 InformationElements.

The Mobile Station Classmark 2 Information includes information on the possibleEGSM 900 capability of the MS. The Mobile Station Classmark 3 InformationElement defines all the frequency bands supported by the MS and the MS powercapabilities in each supported frequency band.

The network receives the Mobile Station Classmark 2 IE in the EstablishIndication message. The Mobile Station Classmark 3 IE is received in theClassmark Change message. The BSC receives both of these messages while therelated 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 bandcapability and about the downlink received BCCH signal level (measurementreport), it defines the usability of different resource types of the segment.

The following formula is used for resource usability estimation whenever achannel inside the segment has to be assigned (in intra-segment SDCCH-SDCCHhandovers, 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 receivedsignal level on the channel. If the MS is using a non-BCCH layer channel, theRXLEV_DL is the downlink signal level of the BCCH carrier of the segment.



9 (59)


Inter-segment resource usability estimation

When the BSC has defined a need for an inter-segment (SDCCH-SDCCH orTCH-TCH) handover based on the measurements of the serving channel, theusability of the different resource types of each candidate segment is decidedusing the BCCH measurement results for the segment and the values of parameternonBCCHLayerOffset for different resource types in the segment accordingto the criterion:

AV_RXLEV_NCELL(n) � nonBCCHLayerOffset>= RxLevMinCell(n)

where

RxLevMinCell(n) is the level which the signal level in the adjacent segment mustexceed in order for the handover to the adjacent segment to become possible.

In a handover between two BSCs, the radio link measurements related to thetarget segment are available on the source side BSC only. It is therefore notpossible 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 onthe nonBCCHLayerOffset parameter. If the non-BCCH layer is regarded as alayer with less coverage (as indicated by the positive value of thenonBCCHLayerOffset parameter), only BCCH frequency band resources areused in channel allocation for external handovers.

Restrictions

1. In the band where the BCCH carrier resides, the common BCCHcontrolled segments must be the same throughout the whole network.BCCH is allowed in the EGSM 900 frequency band only if there is noPGSM 900 frequency band in use in the network.

2. In the Common BCCH feature the BCCH frequency of the segment isadded among the BCCH frequencies that the MS should measure when theMS is active on the non-BCCH band of the segment. This leads to thefollowing 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'sBCCH is located.




When an SDCCH is allocated for an external handover in a multi-bandCommon BCCH segment, the search may be restricted among the BCCHfrequency band resources of the segment. This depends on the frequencyband the BCCH is using. If the non-BCCH layer is regarded as a layer withless coverage (as indicated by the positive value of thenonBCCHLayerOffset parameter), only BCCH frequency bandresources are used in SDCCH allocation for external handovers.

4. In a multiband Common BCCH segment, the TCH for a FACCH setup isalways allocated in the BCCH frequency band of the segment.

5. The dynamic SDCCH RTSLs can be utilised only in the BCCH frequencyband in a Common BCCH cell. This is due to the fact that the multi-bandcapabilities of an accessing MS are not known at the time of the initialSDCCH allocation.

6. The multi-band MS and the multi-band network support FrequencyHopping within each band of operation. Frequency Hopping between thebands of operation is not supported.

7. In the segment environment, only the BCCH BTS can have extended areaTRXs.

8. When a TCH is allocated for an external handover in a multiband CommonBCCH segment, the search may be restricted among the BCCH frequencyband resources of the segment. This depends on the frequency band BCCHis using. If the non-BCCH layer is regarded as a layer with less coverage(as indicated by the positive value of the nonBCCHLayerOffsetparameter), 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 beaccessed only via the regular layer of the BTS.

Handover from super-reuse resources back to the regular layer is notrestricted totally inside the source BTS. But it is limited among thesegment's BTSs that can be regarded as stronger than or equal to the sourceBTS (as indicated by the values of the respectivenonBCCHLayerOffset parameters).

Thechild cell concept is not supported in a BSC that has the segmentoption enabled.

10. GSM-WCDMA Inter-System Handover and Common BCCH Control.

If the features GSM-WCDMA Inter-System Handover and CommonBCCH Control are used together the maximum amount of adjacent cellsand frequencies in a BA list is 30.



11 (59)


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




2 System impact of Common BCCH

2.1 Requirements

2.1.1 Hardware Requirements

Table 1. This table indicates whetherthe feature requires additionalor alternative hardware orfirmware.

Networkelement

Hardware/Firmware required

BSC No requirements

BTS Yes, RF units areband specific, andcorrect RF units areneeded for thesupported frequencybands.

TC No requirements

SGSN No requirements

Common BCCH requires a multi band capable terminal.



13 (59)

System impact of Common BCCH

2.1.2 Software Requirements

Table 2. Network elements requiredsoftware.

Networkelement

Software releaserequired

MSC No requirements

Nokia NetAct OSS3.1 ED1(EnhancementDelivery)

BSC S11

SGSN No requirements

NetAct Planner 4.0

Nokia 2nd Gen. Does not support thisfeature

Nokia Talk-family DF6.0

800/1900 CommonBCCH not supported.

Nokia PrimeSite Does not support thisfeature

Nokia MetroSite CXM4.0

Nokia InSite Not supported byCommon 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




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 amultiband segment result in different radio coverages of the two bands. Themaximum transmission power for the different frequency bands of a multibandsegment needs to be adjusted separately in order to better maintain connection toMSs in the segment. Matching the radio coverage to the same size on both bandsof a multiband segment is done by adjusting the maximum transmission powerfor 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



15 (59)


2.3.2 Common BCCH impact on TRX signalling

Table 4. Common BCCH impact on TRX signalling


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


BSC This feature is managed with BSC MMI.

OSS Common BCCH feature has an impact onOSS.

MSC No impact




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 handlingMML.

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). ParametersMsTxpwrMaxCCH (TXP1) and GPRSMsTxPwrMaxCCH (GTXP1) are usedonly when the BCCH of the segment is either on the GSM800 or GSM900frequency 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 valuesaccording to the BCCH frequency band of the segment. If there is no BCCH TRXin the segment, and there are more than one frequency bands in use in thesegment when POC is created, then GSM900 default values are used if thereexists at least one GSM900 or GSM800 BTS in the segment.

See also parameters bsTxPwrMax and bsTxPwrMax1x00 in the tableCommon BCCH parameters.

Adjacent cell handling

One new parameter GPRSMsTxPwrMaxCCH1x00 (GTXP2) is added to adjacentcell handling MML.



17 (59)


2.4.4 BSS Parameters

Common BCCH parameters

Q3 BSC MML Object Range Defaultvalue

Description

intraSegSDCCHGuard

BSC 0 - 255 (s) 255 With this parameter you define theguard time for attempting an SDCCHhandover from the BCCH BTSresource layer to another resourcelayer in a segment.

btsLoadInSeg BTS 0 - 100(%) 70 With this parameter you determinethe load limit for a BTS. It is used incontrolling the load distributionbetween BTSs in a segment.

SegmentId BTS - Same valueas bts_id

The value range depends on the BSChardware configuration and thecorresponding options.

segmentName BTS 1 - 15characters

Same nameas BTS'sname

With this parameter you identify thesegment by its name.

nonBCCHLayerOffset

BTS -40 - +40dBm

0 dBm With this parameter you definewhether the predefined offset marginis used when evaluating the signallevel of the non-BCCH layer.

nonBCCHLayerAccessThr

Segment -110 - -47dBm

-90 With this parameter you define athreshold value for the estimateddownlink signal level on non-BCCHlayer for a moving MS from BCCHlayer to non-BCCH layer.

nonBCCHLayerExitThr

Segment -110 - -47dBm

-95 With this parameter you define athreshold value for the measureddownlink signal level on non-BCCHlayer for a moving MS from non-BCCH layer to BCCH layer.

nonBCCHLayerExitThr: px

Segment 1 - 32 1 With this parameter you define thetotal number of the averaged valuesof the signal strength downlinkmeasurements for triggering thehandover.

nonBCCHLayerExitThr:nx

Segment 1 - 32 1 With this parameter you define thenumber of averaged signal strengthdownlink measurements for triggeringthe handover.





Description

msTxPwrMaxCCH Segment 5..43 dBmwith 2 dBmstep

33 dBm With this parameter you define themaximum transmission power an MSmay use when accessing a CCH inthe cell for GSM 900/800 bands.

gprsMsTxpwrMaxC-CH

Segment 5..43 dBmwith 2 dBmstep

33 dBm With this parameter you define themaximum transmission power level amobile station can use whenaccessing a packet control channel inthe cell for GSM 900/800 bands.

msTxPwrMaxCCH1-x00

Segment For GSM18000...30dBmwith 2 dBmstep

For GSM1900 0...32dBm

with 2 dBmstep and 33dBm

30 dBm With this parameter you define themaximum transmission power anMS may use when accessing a CCHin the cell for GSM 1800/1900 bands.



19 (59)



Description

gprsMsTxPwrMaxC-CH1x00

Segment For GSM18000...36dBmwith 2 dBmstep

For GSM1900 0...32dBm

with 2 dBmstep and 33dBm

30 dBm

GPRSNonBCCHRx-levLower

BTS -110...-47dBm

-100 dBm With this parameter you define thethreshold when a reallocation to abetter BTS must be made. BTS withthe direct GPRS access BTS optionon is selected. If there are no BTSswith direct GPRS access BTS set toon, the BTS with the lowest nonBCCH layer offset is selected.

GPRSNonBCCHRxle-vUpper

BTS -110...-47dBm

-95dBm With this parameter you define theminimum power level the MS has toreceive to allocate resources from theBTS.

directGPRSac-cessBts

BTS -40...40 dBm 0 dBm With this parameter you define whichBTSs in the SEG may be used forGPRS or EGPRS without signal levelmeasurements. This parameterdefines the signal level comparedto non BCCH layer offset. When thevalue of this parameter is higherthan the value of the parameter nonBCCH layer offset the directGPRS access to non BCCH layerBTS is applied. This is used ininitial channel allocation andreallocation.





Description

bsTxPwrMax

(PMAX1)

BTS 0..30 (dB)with a stepsize of 2

MMLdefault: 0

With this parameter you identify themaximum transmission power of theBTS as an attenuation from the peakpower of the TRX. This parameter isused for frequency bands GSM 800and GSM 900.

bsTxPwrMax1x00

(PMAX2)

BTS 0..30 (dB)with a stepsize of 2

MMLdefault: 0

With this parameter you identify themaximum transmission power of theBTS as an attenuation from the peakpower of the TRX. This parameter isused for frequency bands GSM 1800and GSM 1900.

non BCCH layeraccess threshold(LAR)

The exception is when the BCCH hasbeen configured to GSM 1900 band inGSM800/GSM1900 Common BCCHcell. In that case you define athreshold value for the downlinksignal level on GSM 1900 layer forallowing access to GSM 1900 BCCHlayer.

non BCCH layer exitthreshold (LER)

The exception is when the BCCH hasbeen configured to GSM 1900 band inGSM800/GSM1900 Common BCCHcell. In that case you define athreshold value for the measureddownlink signal level on GSM 1900layer for a moving MS from GSM1900 BCCH layer to GSM 800 layer.

non-BCCHLayerOffset

The nonBCCHLayerOffset parameter is the key parameter of the CommonBCCH feature. It is set at BTS level and for each BTS it defines the signal leveldifference with respect to the BTS carrying the BCCH channel. In order tooptimise the channel allocation procedure in a multi band segment, a self-regulation procedure is implemented in such a way that the network automaticallytunes the nonBCCHLayerOffset value for each BTS within a segment.

2.5 Impact on NSS

No impact.



21 (59)


2.6 Impact on OSS

NetAct support for Common BCCH and Multi BCF features is available inOSS3.1 ED1 onwards. If this release is not available, it is not recommended toactivate Common BCCH and Multi BCF features in the network. In case featuresare activated before OSS3.1 ED1 (or later) is installed, the whole management ofradio network in the sites where Common BCCH and Multi BCF are available,will not work.

Unified Mediation and Adaptation layer interfaces the managed network andprovides 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 BTSradio parameters can be managed from NetAct Radio Access Configurator fromOSS3.1 ED1 onwards. In BSC the Common BCCH and Multi BCF managementis handled via Segment. In Radio Access Configurator the segment managementis done using a master BTS definition. For more information, see the NetActcustomer document Maintaining Multi-BCF Sites.

NetAct Administrator

NetAct Administrator offers full support to Common BCCH and Multi BCFadmin tasks, for example:

. Fast download and activation of Common BCCH and Multi BCF SW toBTSs 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 planningfeature for Common BCCH and Multi BCF. This allows visibility of CommonBCCH and Multi BCF in radio network planning: creation of Multi BCF masterBTSs and Common BCCH allocations. Plans can be completed with RadioAccess Configurator.

NetAct Monitor

Standard Nokia NetAct monitoring applications are used also for monitoring ofCommon BCCH and Multi BCF features. All alarms are available in NetActmonitoring tools.




Reporting for Common BCCH and Multi BCF is done by common Nokia NetActreporting 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 BTSlevel with the current ReportBuilder

. Defining the object (for example, segment ID, BTS, etc.) aggregationmethod on top of the time aggregation formula in the Formula wizard withReportBuilder

. Selecting the Segment ID as hierarchy and Segment ID as summary levelin the dimension selection for report properties

Note that BTS level is still applicable in some cases, although it is in many casesreplaced by segment.

There are also a few new counters in current measurements like HOmeasurement. 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 BSSNetwork Doctor Reports.

NetAct Tracing

Nokia NetAct Tracing supports Common BCCH and Multi BCF capable Nokianetwork 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 thenetwork functionality and possble problems on a call level. Segment informationis available in Trace reports.



23 (59)


NetAct Optimizer

Optimizer supports BSS Common BCCH and Multi BCF features. InternallyOptimizer creates Cell objects based on Segment ID and Master BTS flaginformation. In geographical map view Common BCCH and Multi BCF Cells(Segments) are visible entirely; non-segment BTSs are available as earlier. Twoviews are available in Topology view: new cell (segment) view and old commonobject model view (BSC-BCF-BTS). Adjacency, Power Control and HandOverControl 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.


BSC No impact

MSC No impact

2.7.2 Impact on Abis Interface


BTS No impact

BSC No impact

2.7.3 Impact on Gb Interface


BTS No impact

BSC No impact




2.8 Feature Interoperability

Queuing

Queuing is applied at the segment level. There is no priority between differentmobile types; therefore the mobiles supporting all frequency bands are morelikely to be allocated a channel.

There is no specific reason to vary the values of the parameterstimeLimitCall and timeLimitHandover with respect to the one-layernetwork setting.

The value of the parameter maxQueueLength has to be re-setting, consideringthat the percentage is evaluated on the total number of TRXs (including all BTSsof the segment) and the resulting number should be lower than the number ofavailable SDCCH channels on the BCCH serving layer band. This is becausesome 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 thesegment are not fully utilised (this is the case when the mobile in the queue doesnot support the available capacity). In this case it is very important to make surethat SDCCH capacity is still available for further requests from mobilessupporting the available TCH capacity. For this reason the margin betweenmaxQueueLength and the number of SDCCH channels on the BCCH servinglayer band should be greater than before.

(E)GPRS

Each BTS object in a segment has its own GPRS terrritory. The parameters thatare 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 parameterBTSLoadInSEG the BSC interpretes RTSLs in GPRS territory as busy channels(excluding dedicated GPRS resources). This interpretation prevents the GPRSterritory of a single BTS from shrinking unnecessarily, if there are other BTSs inthe 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.



25 (59)


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 TCHresources of the segment are not fully utilised (this is the case when the mobilecausing a pre-emption does not support the available capacity). The candidate forforced actions is selected from among the resource types that are supported by themobile that initiates the pre-emption procedure. The candidate with the lowestpriority is selected inside the selected frequency bands. Whenever possible, theBTSs that use the same frequency band as BCCH-BTS are the most preferredones. 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 regularlayer of the BTS.

Figure 3. IUO frequency groups in GSM900 /GSM1800 Common BCCHnetwork

Figure 4. IUO frequency groups in GSM800/GSM1900 Common BCCHnetwork

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 800regular TRXs

GSM 800super TRXs

GSM 1900regular TRXs

GSM 1900super TRXs




The target for a super-reuse TCH request is always one BTS (a few TRXs withinthe BTS) and not the whole segment as in resource requests in general. Thehandover from regular resources to super-reuse resources in a BTS is the sameregardless of whether segment architecture is used or not.

When an IUO handover from a super-reuse TRX to the regular resources of aBTS is performed, the information on the usability of different resource types inthe segment is decided based on the values of the parameternonBCCHLayerOffset in the different BTSs of the segment. As a target, theBSC accepts the BTSs whose nonBCCHLayerOffset value is less than orequal to the value of the BTS where the handover was initiated. This is indicatedin the figure Possible handover directions on a segment with dashed-line arrowsgoing from the super-reuse layer of one BTS to the regular layer of another BTSin 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 withthe initial SDCCH, which must be in the BCCH band.

To get an accurate estimation of the C/I value of the Common BCCH segment'snon-BCCH frequency band layer, the estimation is based on the measurement ofthe BCCH frequency in the segment. The C/I calculation is modified so that thesegment's BCCH measurement result is used instead of the serving TCHmeasurement result.



27 (59)


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 alsoBTSs 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 BCFSystem Feature Description.

Frequency Hopping

Frequency Hopping is managed at the BTS level.

BTS1

Regular area

Super reuse area

BTS2

Regular area

Super reuse area




The MA list is a band-specific list formed according to the frequency band theMS is directed to and it is indicated to the MS in the Assignment Command andin the Handover Command. The Immediate Assignment Command alwaysincludes 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 frequencyhopping is applied. The broadcast of the CA list to the MSs in the SystemInformation 1 message only includes the segment's frequencies of the band onwhich the BCCH carrier resides. PGSM 900 and EGSM 900 are regarded asseparate frequency bands.

Frequency hopping between different bands of operation is not supported.Frequencies belonging to different bands used in the same segment are kept apartfrom each other by having separate Cell Allocation and Mobile Allocation listsfor each frequency band of the segment.

Baseband hopping is not recommended for any number of TRXs, it is onlyrecommended in BTS_Object ('sector' in the BTS) that have RTC combiners. Forcombinerless sectors and sectors with Wideband combiners Radio FrequencyHopping 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 forone band in a segment. The hopping groups are formed by grouping the neededTRXs into one BTS and by having several BTSs of the same band. Each BTS hashopping 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 withlower quality within a segment. The idea is that the poorer quality TRXs are onlyused to handle high traffic peaks.

ICE+

ICE+ is possible as it was in BSS9 in a segment that consists of only one BTSobject. If it is used in the BCCH BTS_Object of a Common BCCH segment withseveral BTS objects, then the direct access functionality of ICE+ is onlysupported inside the BTS_Object with the initial SDCCH, which must be in theBCCH band. ICE+ in a non-BCCH BTS_Object is not supported.

When the Common BCCH feature is active, thenonBCCHLayerAccessThreshold parameter in the Handover ControlParameter Handling command group is used for the usability evaluation of thenon-BCCH layer in a segment with resources from different frequency bands. Forthis reason, theIntelligent Coverage Enhancement features cannot be used in asegment with BTSs from both GSM 900/800 and GSM 1800/1900 frequencybands.



29 (59)


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 asegment has resources from different frequency bands, calls can only be handedover to a band other than the BCCH serving layer in the normal area. If differentbands are present in the segment, quite a balanced capacity distribution betweennormal and extended areas can be obtained by configuring almost all TRXsbelonging to the BCCH BTS as extended.

Directed Retry

As in Queuing, also the Directed Retry or the Intelligent Directed Retryprocedure can be triggered even if all resources of a segment are not completelyin use. Since the Directed Retry procedure reduces SDCCH capacity, the DirectedRetry timers should not be set too high and SDCCH capacity should bedimensioned with the proper margin, to avoid SDCCH blocking (due to the DRprocedure) for any mobile supporting the available TCH capacity.

DADL/B

The purpose of the Direct Access to Desired Layer/Band feature is to direct trafficin the call setup phase from the SDCCH of a macro cell/GSM 900/800 cell to aTCH of a micro cell/GSM 1800/1900 cell whenever possible.

In the segment environment, the DADL/B feature can be used to direct trafficbetween segments. The loads are evaluated per segment, adjacency definitionsare between segments, and DADL/B handovers are made between segments. Thefeature activation therefore only makes sense in the case of a single-band segmentenvironment.

AMH

The BSC-controlled traffic-reason handover is a segment level procedure whichincludes the related parameters. The loads are evaluated per segment, and the ideais that the power budget margin is dynamically changed to direct the MSshanging around on the segment border to less loaded adjacent segments.

Nevertheless, if each segment is dimensioned to handle the needed capacity (as itshould be with the Common BCCH feature, considering that 3 different bandscan be used and up to 36 TRX objects are allowed in a segment), the trafficshould be smoothed out among the BTSs within a segment, rather than directed toadjacent segments. Therefore, when the Common BCCH feature is active and thesegments are multi-band, the AMH feature is less beneficial.




Dynamic Hot Spot

The Dynamic Hot Spot control operates on the BTS level. The usability of agiven frequency band is defined by examining the interference of the respectiveband in the neighbouring cells. Here PGSM 900 and EGSM 900 are regarded asone GSM 900 band and the examinations are made accordingly. The dynamic hotspot algorithm is applied when the number of busy TSLs in the layer where TCHis requested exceeds the threshold parameter softBlockingStartReg.

Since adjacencies are defined on the segment level, the interfered cells are alsodefined at the segment level: all the possible BTSs of an adjacent segment areexamined (layer by layer) if the segment has been defined as an interfered cell.For the feature to work properly, frequency-hopping groups must be allocatedusing the same criteria for all frequency bands. This means that all the layers of agiven segment are interfered by the corresponding layers of the interferingsegment. In the soft blocking evaluation, the contributions from BTSs belongingto the same band are summed up and if different frequency groups are assigned toBTSs belonging to the same band and same segment, frequency groups should beassigned in all the interfered segments.

A non-uniform network where one-band segments exist together with multi-bandsegments 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 anon-hopping TRX or an internal inter-segment handover is performed because ofbad signal quality.

Minimum acceptable C/N ratio in channel allocation

If the value of the parameter CNThreshold varies between the BTSs of thesame resource type, the BSC selects the highest value for calculation. Therecommendation for a certain resource type in the segment is disabled when thevalue 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 theBTSs 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 isdisabled when the value is not used even in one of the TRXs of the BTSs of thesame resource type.



31 (59)


FACCH Call Setup

FACCH Call Setup means allocating a TCH for the signalling phase of a call in aSDCCH congestion. Thus, the same restrictions apply for FACCH Call Setup asfor 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 beenmaintained to some extent in the segment environment. This is examined after theBTSs of a segment have been compared on the basis of their loads and theirrespective 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 SpeedCircuit Switched Data feature.

The main change concerning HSCSD is that HSCSD resource allocation is madeaccording to the capabilities of an MS considering the radio conditions and theloads of the different resource types. Among the BTSs that the BSC defines asreasonable, the TCH search is performed so that the HSCSD channelconfiguration 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 aBCCH-BTS of the segment is in the state locked when another BTS in the SEG isshut down, only an inter-cell handover is possible. The same applies when theBCCH-BTS itself is shutting down.

Dual Band

Note

Common BCCH replaces the Dual Band. Dual Band is replaced by CommonBCCH, but is still available for cases where BTS Site & Cell definitions still useseparate BCCHs for each of the bands. Use Common BCCH if possible.

Common BCCH has requirements that have to be taken into account. Forexample that the BTS objects of different frequency bands that are combinedwithin a common BCCH controlled segment have to be co-sited andsynchronised.




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




33 (59)





3 Planning Common BCCH

3.1 Common BCCH and handover

In a Common BCCH segment environment, new types of handovers have beenintroduced. Also, handovers between different BTSs can occur inside the samesegment or between different segments. The following handover types have beenadded:

. Intra-BTS (intra-segment) handover; equivalent to the old intra-cellhandover

. Inter-BTS intra-segment handover

. Inter-segment internal (intra-BSC) handover

. Inter-segment external (inter-BSC) handover; equivalent to the old externalhandover

The inter-BTS handovers can occur within the same frequency layer or betweendifferent frequency layers.

Handover causes

. Power Budget Handover

The standard PBGT (power budget) calculation is applied for an MS on thePGSM 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 thePBGT handover is based on the measurement of the segment's own BCCHfrequency that the MS measures when on the GSM 1800 band. The BCCHmeasurements are compared with each other to decide the superioritybetween the serving and an adjacent segment.

. Load based TCH handover

In addition to the standard TCH � TCH handovers, when the CommonBCCH is active, the BSC can command an additional handover to balancethe load between different frequency bands.



35 (59)

Planning Common BCCH

During the call setup procedure the load cannot necessarily be kept underthe BTSLoadInSEG limit for each BTS, because not all terminals supportall the resource types. Furthermore, due to their propagation properties, theGSM 1800/1900 resources may not be available in all TCH allocationcases.

When deciding on initiating a handover to balance the load between theBTSs 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 theBCCH BTS has to be over 50% in order to calls are moved to the otherBTS of non BCCH layer. If the BTSLoadInSEG-parameter is set to value1%..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 CD3.0for 13.13-0 environment. This has an impact on cases where resources onthe BCCH-layer are scarce.

As an improvement, the possibility to trigger an intra cell handover fromthe BCCH layer BTS irrespective of the load in the BTS has beenimplemented. The value 0 of BTSLoadInSEG-parameter has now a specialmeaning. When the operator has set it to value 0, the BSC tries to hand allcalls fullfilling signal strength criterias over from the BCCH layer BTS tonon BCCH layer. This causes that the resources on the BCCH layer arekept free as far as possible.

Since in GSM900/GSM1800 the main purpose of the handover is to movethe TCH load from the GSM 900 bands to the GSM 1800 band and EGSMband, respectively, these two bands are the only possible targets (withpriority given to the 1800 band).

In GSM 800/1900, it may be preferable to use a handover that moves theTCH load from the GSM 1900 band to the GSM 800 band instead offreeing the TCH for a single-band GSM 1900 mobile.

The BSC checks the load of the GSM 900/800 BTS every time it receives aTCH request for the segment in question. When the BSC selects targetBTSs for a load based intra cell handover, it only accepts BTSs whose loadis 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 SDCCHreservations, thus reducing the SDCCH pressure on the BCCH resource layer.




This handover is triggered when the length of an SDCCH reservation on theBCCH layer equals the value of the intraSegSDCCHHoGuard parameter.

The handover is performed if there are available SDCCH resources outside theBCCH band and the MS has the required capability.


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 theinformation on the frequency capability of the accessing MS and on theusability of radio resources in different frequency bands.

The BTSs are divided into groups according to their frequency band (BTSsusing the BCCH frequency band form one group and BTSs using afrequency other than the BCCH frequency band form another group).

The SDCCH load of each BTS group is calculated taking into account onlythe static SDCCH resources. The channel is allocated from the BTS groupthat 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 BTSswith an RF hopping TRX prioritisation, the priority is given to non-BCCHTRXs. The SDCCH channel from the BCCH TRX is allocated only if thereare no idle SDCCHs in other TRXs at all.

. RTSL selection:

The RTSL that has the highest number of idle SDCCH channels left isselected. However, if a signalling channel was last allocated from the sameTRX, another RTSL than last time is allocated, when possible.

If there are no idle static SDCCH resources in the BTSs, dynamic SDCCHresources are searched for in every BTS group. From all TRXs, the RTSLwhich has the least idle dynamic SDCCH channels is selected.



37 (59)


SDCCH assignment (Immediate Assignment)

In a multi-band Common BCCH segment, the initial SDCCH channel for a callsetup 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 MSsends the establish indication message. It is not possible to define the usability ofthe non-BCCH frequencies of the segment, as the MS only starts sendingmeasurement reports after it has been moved to a dedicated channel.

Within the BCCH frequency band, the SDCCH to be allocated is selectedaccording to the algorithm described above.

If there are no idle static or dynamic SDCCH resources in the BTSs, an idle TCHtimeslot is configured as a new temporary SDCCH resource. Dynamic SDCCHreconfiguration is only applied in the Immediate Assignment phase, not inhandovers.

SDCCH external handover

During inter-BSC handovers, the usability of radio resources in differentfrequency 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 positivevalue of the nonBCCHLayerOffset parameter), only BCCH frequency bandresources are used in the SDCCH allocation for an external handover. (If theBCCH is on GSM 900/800, the EGSM 900 band can also be utilised according tothe MS capabilities.) If the non-BCCH layer is regarded as a layer with morecoverage (as indicated by the negative value of thenonBCCHLayerOffsetparameter), the non-BCCH layer resources can also be used in the SDCCHallocation 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 thebasic procedure. The SDCCH is trying to be allocated in a TRX other than thecall 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 theserving one is defined in the BTS). If the call-serving TRX is blocked, the basicsearch procedure is used.

TCH assignment

The basic difference between TCH allocation in a Common BCCH controlledsegment and a single BTS cell is that the target of a TCH request in a segment is aset of BTSs instead a single BTS. Basically, all existing rules for selecting a TCHin a single BTS cell are also valid between BTSs in a segment cell. The generalprocess for TCH selection is as follows:




. BTS(s) selection:

The BTSs where a TCH can be allocated are filtered on the basis of theinformation on the frequency capability of the accessing MS and on theusability of radio resources in different frequency bands.

The BTSs are filtered according to their load. The load calculation is basedon the BTS-specific parameter BTSLoadInSEG. TCHs are assigned fromthe BTSs whose load is less than the BTSLoadInSEG value. See chapterHandover causes.

When each BTS has reached its load limit the allocation continues in thoseBTSs where the load is less than the highest load threshold value amongthe BTSs.

When the load in all the BTSs has reached the level of the highest loadthreshold value among the BTSs, the GSM 1800 band, the EGSM 900, andPGSM 900 bands are respectively preferred. Therefore the prioritisationbetween the frequency layers is applied only in high-load conditions,where the better GSM 900 resources are saved for the MSs with limitedfrequency capability or in the cell border area.

. RTSL(s) selection:

After the primary target group of BTSs for TCH allocation has beenselected, all the idle RTSLs are ranked according to their interference leveland to the interference level recommendation defined in the BTS theybelong to.

If there are several candidate RTLSs with the same interference level, theTRX prioritisation in TCH allocation is applied: the RTSL is allocatedfrom the BCCH TRX or from a non-BCCH TRX according to the definedprioritisation.

If several candidate RTLSs exist after applying the TRX prioritisation inTCH allocation, the RTSL is allocated from the BTS with the lowestCircuit Switched load by using the round robin method so that the BTSallocated the previous time is the last choice.


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



39 (59)


Case 2: Common BCCH GSM Network (GSM 900/800 and GSM 1800/1900BTSs 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 = 5

5 SDCCH channels are necessary for each BTS. So aseparated channel configuration is needed for eachBTS (TS0 is dedicated for the BCCH channel and TS1 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 tosmaller 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 = 3.8Erl/Cell

Number of SDCCH channels = 10. A separatedconfiguration is needed, with 2 TS for SDCCH on theBCCH layer.





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 beactivated/disabled with the WOA command.

The following implementation instructions of Common BCCH in Nokia networkare for GSM800 and GSM1900. The same procedure can be applied toimplement 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 givesinstructions on how to plan and prepare parameter changes, for examplewhen bringing new features into use in the GSM and WCDMA networks.



41 (59)

Implementing Common BCCH

4.2 Creating a multiband cell (segment)

Purpose

Create a multiband segment by creating a new GSM 800 BTS to an existing GSM1900 segment.

Before you start

The preconditions for a multiband segment creation are that the existing segmenthas one BTS using the GSM 1900 frequency band that has all TRXs in the WOstate. During the BSC software installation, the system has created a SEG foreach existing BTS. The number of the SEG is the same as the number of therelated BTS, for example BTS-12 => SEG-12.

You can use the create BTS and TRX commands of the BSC MML or NetAct tocreate 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 andTRXs of the SEG

EEI:SEG=<seg_id>;

b. Create a BTS (GSM 800) to a segment that has one BTS using theGSM 1900 frequency band.

Note

Because the segment already exists, the MML does not allow the user to definecell (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 allTRXs of the SEG

EEI:SEG=<seg_id>;




Examples:

a. ZEEI:SEG=44;

SEG-44:

BCF-044 ULTRA SITE

BTS-044 (GSM 1900)

TRX-001 (MBCCHC)

TRX-002

b. ZEQC:BCF=44,BTS=77,SEG=44:BAND=800;

c. ZEEI:SEG=44;

SEG-44:

BCF-044 ULTRA SITE

BTS-044 (GSM 1900)

TRX-001 (MBCCHC)

TRX-002

BTS-077 (GSM 800)

2. Delete the old BCCH channel

Delete the BCCH channel from the BTS using the GSM 1900 frequencyband.

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 TCHchannel

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 frequencyband. Create the BCCH channel.

a. Create the BCCH TRX

ERC:BTS=<bts_id>,TRX=<trx_id>:FREQ=<freq>,



43 (59)


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;

BCF-044 ULTRA SITE

BTS-044 (GSM 1900)

TRX-001

TRX-002

BTS-077 (GSM 800)

TRX-003 (MBCCHC)

4. Modify the parameter MsTxpwrMaxGSM(PMAX1) for the new BTSusing the GSM 800 band

Skip this procedure if the default value of the parameter PMAX1 (themaximum power level that an MS may use in the serving cell) is goodenough.

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 theBCCH or PCCCH of a cell in which the BCCH is on the GSM 800frequency band is defined with the parameters MsTxpwrMaxCCH(TXP1)and GPRSMsTxpwrMaxCCH (GTXP1). The default value for bothparameters is 33 dBm. You can skip this procedure if the default value isapplicable for both parameters.




Note

You can only modify the parameters via segment identification if the segment hasmore 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 theGSM 1900 band values are also applicable to the new BTS using the GSM800 frequency band. Check that the GSM 800 / GSM 900 frequency bandspecific power control parameter bs tx pwr max (PMAX1) has anapplicable value. If not, modify the power control parameters of thesegment.

Note

You can modify the power control parameters only via segment identification ifthe segment has more than one BTS. The new value is set for all BTSs of thesegment.

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:



45 (59)


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 TRXand the BCCH BTS of the segment.

Modify the value of the nonBCCHLayerOffset parameter. Whencreating 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 thepeak power of the TRX and have to be taken into account when defining thevalue for parameter nonBCCHLayerOffset (NBL).

Note

The parameter nonBCCHLayerOffset (NBL) is used to indicate how muchweaker 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 BCCHBTS. A positive value of the NBL in a BTS indicates a signal level lower than inthe BCCH BTS and prevents the SDCCH allocation for call setups and externalhandovers in that BTS.

8. Define the load limit for a BTS




Define the load limit for a BTS with the parameter LSEG(BTSLoadInSEG). You can determine separate LSEGs for all BTSs ofthe segment. LSEG is used in controlling the load distribution betweendifferent BTSs in a segment. The default value when creating a BTS is70%. 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 onthe non-BCCH frequency layer

Define the threshold value for a segment with the parameternonBCCHLayerAccessThreshold (LAR).

LAR is a threshold value for the estimated downlink signal level on thenon-BCCH frequency layer of the segment for moving an MS from theBCCH frequency layer to the non-BCCH frequency layer. The defaultvalue 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-BCCHfrequency layer to the BCCH frequency layer

Define the threshold for a segment with the parametersnonBCCHLayerExitThreshold (LER) ,nonBCCHLayerExitThresholdpx (LEP), andnonBCCHLayerExitThresholdnx (LEN).



47 (59)


LER is a threshold value for the measured downlink signal level on thenon-BCCH frequency layer for handing an MS over from the non-BCCHfrequency layer to the BCCH frequency layer. LEP and LEN can be usedto define how many of the measurement reports must be below the LER totrigger the handover. The default value for LER is �95 dBm, the defaultvalue for LEP is 1, and the default value for LEN is 1. If you want tochange the values, use the command EHS.

Handover from the non-BCCH frequency layer to the BCCH frequencylayer is made only if the BCCH frequency layer of the segment has morecoverage than the non-BCCH frequency layer. These three parameters areused by the BSC only when the BCCH frequency layer of the segment hasmore coverage than the non-BCCH frequency layer. Otherwise they areignored.

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 theGSM 1900 band values are also applicable to the new BTS using the GSM800 frequency band. Check that the GSM 800 / GSM 900 frequency bandspecific power control parameter bs tx pwr max (PMAX1) has anapplicable value. If not, modify the power control parameters of thesegment.

Note

You can modify the power control parameters only via segment identification ifthe segment has more than one BTS. The new value is set for all BTSs of thesegment.

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>;




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 adjacentcell information with the EAC command, but if the segment has more thanone BTS you have to use segment identification as a parameter instead ofBTS identification.

a. Create an adjacent cell for a segment that has more than one BTSand 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 BTSand 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 itselfis added among the BCCH frequencies that the MS should measure whenon the non-BCCH frequency band of the multiband segment. This leads tothe following restriction: a segment can have only 31 adjacent cells.

If the inter-system handover feature is used with the Common BCCHControl feature then the maximum number of adjacent cells is restricted to30. Skip this procedure if the segment does not have 32 or 31 adjacentcells. 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;



49 (59)


14. Modify the BA list <option>

In the Common BCCHl feature, the BCCH frequency of the segment itselfis added among the BCCH frequencies that the MS should measure whenthe Common BCCH feature is activated. This leads to the followingrestriction: there can be only 31 frequencies in a BA list.

If the Inter-System Handover feature is used with the Common BCCHfeature, 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 have32 or 31 BCCH frequencies. Otherwise remove one or two BCCHfrequencies 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 onefrequency 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:




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 BTSmust be unlocked first. When you unlock a non-BCCH BTS, then theBCCH 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


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 callshould be possible via both BTSs. Synchronized handovers are usedbetween the BTSs. The system has set synchronized handovers on bydefault.

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.



51 (59)


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 BTSusing the GSM 1900 frequency band to a new, separate segment. If you want tomove the BTS, which has the BCCH TRX, you must first delete the BCCHchannel because moving a BTS containing a BCCH TRX is not allowed. AllBTSs of the old segment must be in the locked state. For an overview, seeOverview 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;


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




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-specificparameters 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 800frequency bands

a. Lock a TRX of the BTS using the GSM 1900 frequency band


b. Define the BCCH channel to the TRX of the BTS using the GSM1900 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 800frequency 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 cellfor both segments

The maximum transmission power that an MS may use when accessing theBCCH or PCCCH of a cell in which the BCCH is on the GSM 1900frequency band is defined with the parameters MsTxpwrMaxCCH 1x00(TXP2) and GPRS MsTxpwrMaxCCH 1x00 (GTXP2). The defaultvalue for both parameters is 30 dBm.

The maximum transmission power that an MS may use when accessing theBCCH or PCCCH of a cell in which the BCCH is on the GSM 800frequency band is defined with the parameters MsTxpwrMaxCCH(TXP1) and GPRS MsTxpwrMaxCCH (GTXP1). The default value forboth parameters is 33 dBm.



53 (59)


You can skip this procedure if the default values are applicable for bothsegments.

Note

You can modify the parameters only via segment identification if the segment hasmore than one BTS.

a. Modify the TXP2 and GTXP2 of the segment in which the BCCH ison 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 donebecause the power control (POC), handover control (HOC), andadjacencies do not follow the moved BTS to the new segment. You have todefine the POC, HOC, and any adjacencies needed for the new segmentlike in BTS creation.

You can now modify the power control and handover control parametersvia segment identification or via BTS identification because the segmentthat has the BTS that was moved only has one BTS.

a. Create power control parameters

Create power control parameters for the new segment by usingeither SEG or BTS identifier.

EUC:SEG=<seg_id>;

or

EUC:BTS=<bts_id>;




b. Create handover control parameters

Create handover control parameters for the new segment by usingeither 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 isunder 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 BTSmust 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


b. Unlock the BTS that was moved

EQS:BTS=<bts_id>:U;



55 (59)


c. Unlock the BCCH TRX of the BTS using the GSM 1900 frequencyband


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 anotherexisting 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 wasmoved starts to use the new segment's parameters. After moving the BTS youmust unlock all BTSs of the old and the new segment.

Note

When you combine two segments together, move all BTSs of one segment to anew existing segment. After moving all BTSs the old segment does not exist anymore.

Note

TheGPRS has to be disabled in all BTSs in both segments when moving a BTSfrom one segment to another.




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 newexisting segment which has one BTS. The BCCH TRX is not under theBTS 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:

BCF-033 ULTRA SITE

BTS-033 (GSM 800)

TRX-001 (MBCCHC)

TRX-002

BTS-55 (GSM 800)

TRX-3

ZEEI:SEG=66;

SEG-66:

BCF-066 ULTRA SITE

BTS-066 (GSM 800)

TRX-001 (MBCCHC)

TRX-002



57 (59)


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 andTRXs 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;




SEG-33:

BCF-033 ULTRA SITE

BTS-033 (GSM 800)

TRX-001 (MBCCHC)

TRX-002

ZEEI:SEG=66;

SEG-66:

BCF-066 ULTRA SITE

BTS-066 (GSM 800)

TRX-001 (MBCCHC)

TRX-002

BTS-55 (GSM 800)

TRX-3

Further information

For an overview, see Overview of implementing Common BCCH .



59 (59)


Date post:	24-Oct-2014
Category:	Documents
Upload:	emonlaa
View:	429 times
Download:	6 times

Common BCCH System Feature

Documents