01-05 multiband network- 900-1800mhz

5 Multiband Network

About This Chapter

5.1 OverviewThis describes the definition and purposes of the multiband network. The multiband networkfeatures multiple frequency bands in one network, which increases the utilization ratio of radiofrequency resources.

5.2 AvailabilityThis lists the NEs, software, and MS required for the implementation of the multiband network.

5.3 Technical DescriptionThis describes the technical aspects of the multiband network. The multiband network allowsthe BSC to manage multiple frequency bands, enables the operator to extend the frequency band.Thus, the utilization of frequency resources can be improved.

5.4 ImplementationThis describes how to configure, verify, and deactivate the multiband network.

5.5 Maintenance InformationThis lists the alarms and performance counters related to the multiband network.

5.6 References

HUAWEI BSC6000 Base Station SubsystemBSS Feature Description 5 Multiband Network

Issue 03 (2008-01-25) Huawei Proprietary and ConfidentialCopyright © Huawei Technologies Co., Ltd

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5.1 OverviewThis describes the definition and purposes of the multiband network. The multiband networkfeatures multiple frequency bands in one network, which increases the utilization ratio of radiofrequency resources.

Definition

A multiband network consists of multiple frequency bands.

Huawei GSM BSS supports the following types of multiband networks:

l GSM850 band + GSM900 band + GSM1800 band

l GSM850 band + GSM900 band + GSM1900 band

The most commonly used multiband networks are the dual-band networks, which are GSM900band + GSM1800 band, and GSM850 band + GSM1900 band.

NOTE

l GSM900 band is the most widely used frequency band in the GSM network.

l To be distinguished from E-GSM900 band and R-GSM900 band, the standard GSM900 band is referredto as P-GSM900 band in the GSM protocols. GSM1800 band is referred to as DCS1800 band, andGSM1900 band is referred to as PCS1900 band.

l GSM1800 band and GSM1900 band have many frequencies in common, so the two frequency bandscannot constitute a multiband network.

Purposes

The multiband network allows the BSC to manage multiple frequency bands, enables theoperator to extend the frequency band. Thus, the utilization of frequency resources can beimproved.

NOTE

With the large-sale development of the GSM network, the limited radio frequency resources become thebottleneck in the further development of the GSM business. The introduction of, however, extendedfrequency bands of E-GSM and R-GSM effectively relieves the insufficiency of radio frequency resources.

Terms

None.

Acronyms and Abbreviations

Acronyms andAbbreviations

Full Spelling

BCCH Broadcast Control Channel

BA BCCH Allocation

CM Classmark

5 Multiband NetworkHUAWEI BSC6000 Base Station Subsystem

BSS Feature Description

5-2 Huawei Proprietary and ConfidentialCopyright © Huawei Technologies Co., Ltd

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Acronyms andAbbreviations

Full Spelling

ECSC Early Classmark Sending Control

MBR Multiband Report

CBQ Cell Bar Qualify

CBA Cell Bar Access

CDU Combining and Distribution Unit

PBU Power Boost Unit

5.2 AvailabilityThis lists the NEs, software, and MS required for the implementation of the multiband network.

NEs InvolvedTable 5-1 lists the NEs involved in the multiband network.

Table 5-1 NEs involved in the multiband network

MS BTS BSC MSC MGW SGSN GGSN HLR

√ √ √ √ – – – –

NOTE

l –: not involved

l √: involved

Software ReleasesTable 5-2 lists the version mapping requirements for the BTS software.

Table 5-2 GBSS products and software versions

Product Version

BSC BSC6000 V900R003C01 andlater releases

BTS BTS3012AE BTS3000V100R001C04 and later releases



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Product Version

Other BTS types Neither PCS1900 bandnor GSM850 band issupported by thereleases beforeNovember 11th, 2004.

BTS3X G3BTS32V302R002C05 and later releases

MiscellaneousThe multiband network requires the MS to support corresponding multiple bands. The MSsupporting a single frequency band can also gain access to the multiband network, but campsonly on the corresponding frequency band in the multiband network.

At present, Huawei GSM BSS supports 900 MHz band (P-GSM900 band, E-GSM900 band,and R-GSM900 band), 1800 MHz band (DCS1800 band), 1900 MHz band (PCS1900 band),and 850 MHz band. Huawei GSM BSS does not support GSM450 band or GSM480 band.

In terms of cell, Huawei GSM BSS supports GSM900/DCS1800 Co-BCCH cell, and does notsupport GSM850 /PCS1900 Co-BCCH cell.

5.3 Technical DescriptionThis describes the technical aspects of the multiband network. The multiband network allowsthe BSC to manage multiple frequency bands, enables the operator to extend the frequency band.Thus, the utilization of frequency resources can be improved.

5.3.1 Frequency Band SegmentationThis describes the frequency band division for a multiband network. A multiband networkconsists of multiple frequency bands. Good frequency band division is the crucial prerequisitefor proper operation of the multiband network.

5.3.2 Frequency Assignment for TRXsThis describes the frequency assignment for TRXs. The TRXs configured on the BTS mustsupport related frequency bands to enable a multiband network.

5.3.3 Multiband Channel AssignmentThis describes the multiband channel assignment. In channel assignment, the multiband channelassignment considers the capability of the MS and the channel itself to support the frequencybands. The channel assignment strategy depends on the practical application.

5.3.4 Frequency Band FeaturesThis describes the features of frequency bands. The performance of a network can be improvedwith a proper networking mode based on the features of different frequency bands.

5.3.5 Multiband Network TopologyThis describes the multiband networking mode. The networking mode for a multiband networkis of three types: independent MSC networking, Co-MSC/independent BSC networking, andCo-BSC networking. The former two types are referred to as independent networking, and thelatter one is referred to as hybrid networking.




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5.3.6 Technical PrinciplesThis describes the technical principles related to the multiband network. Based on the principles,you need to correctly configure related parameters at the network enabling stage to ensure theperformance of the multiband network.

5.3.7 Traffic Guiding StrategyThis describes the traffic guiding strategy of the multiband network. To meet the increasinglyhigh requirements on capacity and quality of the multiband network, the DCS1800 band isrequired to absorb or share the traffic volume at a maximum extent.

5.3.8 Enhanced Dual-Band NetworkThis describes the enhanced dual-band network that is an improvement on the existing dual-band network. In the enhanced dual-band network, two co-sited cells with different coverageareas are logically formed into a cell group. One is an overlaid subcell and the other is anunderlaid subcell. The enhanced dual-band network algorithm enables the channel resourcesharing and the cell load balance between the two cells in a cell group.

5.3.1 Frequency Band SegmentationThis describes the frequency band division for a multiband network. A multiband networkconsists of multiple frequency bands. Good frequency band division is the crucial prerequisitefor proper operation of the multiband network.

There are eight frequency bands available for the multiband network. Table 5-3 lists the mappingbetween the Absolute Radio Frequency Channel Number (ARFCN) and the frequency in everyfrequency band.

Table 5-3 Mapping between the ARFCN and the frequency

FrequencyBand

Uplink Frequency Downlink Frequency ARFCN

P-GSM900 band Fl(n) = 890 + 0.2 x n Fu(n) = Fl(n) + 45 1 ≤ n ≤ 124

890–915 MHz 935–960 MHz

E-GSM900 band Fl(n) = 890 + 0.2 x n Fu(n) = Fl(n) + 45 0 ≤ n ≤ 124

Fl(n) = 890 + 0.2 x (n –1024)

975 ≤ n ≤ 1023

880–915 MHz 925–960 MHz -

R-GSM900 band Fl(n) = 890 + 0.2 x n Fu(n) = Fl(n) + 45 0 ≤ n ≤ 124

Fl(n) = 890 + 0.2 x (n –1024)

955 ≤ n ≤ 1023

876–915 MHz 921–960 MHz -

DCS1800 band Fl(n) = 1710.2 + 0.2 x(n – 512)

Fu(n) = Fl(n) + 95 512 ≤ n ≤ 885

1710–1785 MHz 1805–1880 MHz

PCS1900 band Fl(n) = 1850.2 + 0.2 x(n – 512)

Fu(n) = Fl(n) + 80 512 ≤ n ≤ 810



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FrequencyBand

Uplink Frequency Downlink Frequency ARFCN

1850–1910 MHz 1930–1990 MHz

GSM850 band Fl(n) = 824.2 + 0.2 x (n– 128)

Fu(n) = Fl(n) + 45 128 ≤ n ≤ 251

824–849 MHz 869–894 MHz

GSM450 band Fl(n) = 450.6 + 0.2 x (n– 259)

Fu(n) = Fl(n) + 10 259 ≤ n ≤ 293

450.4–457.6 MHz 460.4–467.6 MHz

GSM480 band Fl(n) = 479 + 0.2 x (n –306)

Fu(n) = Fl(n) + 10 306 ≤ n ≤ 340

478.8–486 MHz 488.8–496 MHz

NOTE

In Table 5-3, n indicates the Absolute Radio Frequency Channel Number and the frequency is in unit ofMHz. Fl(n) indicates the uplink frequency corresponding to n. On the uplink frequency, the MS sendssignals to the BTS. Fu(n) indicates the downlink frequency on which the BTS sends signals to the MS.

For frequency band division, you still need to keep the following in mind:

l The E-GSM900 band, R-GSM900 band, and P-GSM900 band are in the same frequencyband without adjacent frequencies.

l The E-GSM extended band refers to the band that does not contain the P-GSM band.

l The R-GSM extended band refers to the band that does not contain the E-GSM band.

5.3.2 Frequency Assignment for TRXsThis describes the frequency assignment for TRXs. The TRXs configured on the BTS mustsupport related frequency bands to enable a multiband network.

Table 5-4 lists different ranges of ARFCN that every TRX supports.

Table 5-4 Ranges of ARFCN that TRXs support

TRX Range of ARFCN

PTRX 1 ≤ n ≤ 124

ETRX 0 ≤ n ≤ 124975 ≤ n ≤ 1023

RTRX 0 ≤ n ≤ 124955 ≤ n ≤ 1023

DTRX 512 ≤ n ≤ 885




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TRX Range of ARFCN

PETR 512 ≤ n ≤ 810

EETR 128 ≤ n ≤ 251

RETR 0 ≤ n ≤ 124955 ≤ n ≤ 1023

DETR 512 ≤ n ≤ 885

TRX The TRX converts to PTRX or DTRX based on frequencies. The TRX helpsthe system decide the frequency band support for TRX mutual aid.NOTE

For the candidate TRX selection in TRX mutual aid, the frequencies of the source TRXmust be interchangeable with those of the target TRX. That is, the TRX, CDU, and PBUof the target/source TRX must support all the frequencies configured for the source/targetTRX.

5.3.3 Multiband Channel AssignmentThis describes the multiband channel assignment. In channel assignment, the multiband channelassignment considers the capability of the MS and the channel itself to support the frequencybands. The channel assignment strategy depends on the practical application.

Channel Assignment Algorithm II

In a channel assignment procedure, the system decides the capability of every channel to supportthe MS based on the MS classmark, and then preferentially assigns the channel on the bandoutside of the band intersection to the MS.

For an MS that supports the E-GSM band, if the available channels are carried on the P-GSMband and the E-GSM extended band, the channel on the E-GSM extended band is preferentiallyassigned to the MS. The band intersection, P-GSM band, is assigned to other MSs with weakband supporting capability.

Channel Assignment Strategy

In a channel assignment procedure, the system decides the capability of every channel to supportthe MS based on the MS classmark.

l If the MS classmark 3 is valid, the system decides based on the MS classmark 3.

l If the MS classmark 3 is invalid, the band supported by the MS is updated to the band wherethe BCCH is carried.

For example, the BCCH is carried on the E-GSM extended band. When the MS classmark 3 isinvalid, the band supported by the MS becomes the E-GSM extended band (because the E-GSMextended band contains the P-GSM band, the MS supports the P-GSM band at the same time).

The BSC filters the unqualified channels and assigns the channel with the highest priority levelto the MS.



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The priority level of a channel consists of four bytes with one bit indicating one frequency band.The bit corresponding to the frequency band that the channel is carried on is set to 1. See Figure5-1.

Figure 5-1 Frequency band bit for channel priority

TCH/Band_P

TCH/Band_R

TCH/Band_E

TCH priority ...

...

...

...

...

...

...

...

P E R 850 480 1900450 1800

1 0 0 0 0 00 0

0 1 0 0 0 00 0

0 0 1 0 0 00 0

The greater the bit value is, the lower the priority level of the corresponding channel is. Forexample, if an MS supports the R-GSM band, the TCH carried on the P-GSM, E-GSM, or R-GSM band can be assigned the MS. Based on the channel priority, which is R-GSM > E-GSM> P-GSM, the TCH carried on the R-GSM band is preferentially assigned to the MS.

The band carrying the TCH is determined by the TRX, and the band of the TRX is determinedby the assigned frequency. For example, the assigned frequency for RTRX is in the P-GSMband, and therefore the TCH on RTRX is carried on the P-GSM band.

In case of immediate assignment, the system assigns the channel for the MS based on thefrequency band where the BCCH is carried.

5.3.4 Frequency Band FeaturesThis describes the features of frequency bands. The performance of a network can be improvedwith a proper networking mode based on the features of different frequency bands.

NOTE

l The features of the 1900 MHz band are similar to those of the 1800 MHz band.

l The features of the 850 MHz band are similar to those of the 900 MHz band. The 850 MHz band andthe 900 MHz band feature strong penetration and wide coverage.

l The features of the 850 MHz band are in opposition to those of the 1800 MHz band.

Due to the previously mentioned points, only the features of the 1800 MHz band are described as below.

Propagation Features of 1800 MHz Band

The working frequency of the 1800 MHz band is twice that of the 900 MHz band. Therefore,there are following differences in propagation loss between the 1800 MHz band and the 900MHz band:

l In Line of Sight (LOS), the propagation loss of the 1800 MHz band is 6 dB greater thanthat of the 900 MHz band.




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l Out of Line of Sight (LOS), the propagation loss of the 1800 MHz band is 10 dB greaterthan that of the 900 MHz band.

l In a building, the propagation loss of the 1800 MHz band is 5–17 dB greater than that ofthe 900 MHz band (associated with materials).

Fast fading of the 1800 MHz band unfavorably affects the network coverage, which directlydegrades the network performance. In terms of the diffraction capability of the electromagneticwave, the 900 MHz band outperforms the 1800 MHz band.

Coverage Requirements for 1800 MHz BandThe coverage of the 1800 MHz band is applied to two applications:

l Outdoor coverageThis application is easily implemented with small distance between BTSs. If necessary,add the equipment supporting the DCS1800 band at the original GSM900 BTS site, andadd BTSs at suitable places.

l Indoor coverageTo ensure a good indoor coverage of the DCS1800 band, Huawei recommends that thedistance between BTSs in downtown be less than 1,000 m, with 500–800 m preferably.

Coverage Mode of 1800 MHz BandThe network coverage of the 1800 MHz band in a multiband network can be implemented inthe following ways:

l Complete continuous coverageThe features of complete continuous coverage are:– High traffic-absorbing capability, few inter-layer handover, and high network

performance– Easy frequency planning, network optimization, and traffic distribution control

– Site deployment once for all, stepwise capacity expansion for TRXs based onrequirements, and convenient construction and maintenance

– Huge investment, and difficulty in selecting all the sites at a time

l Continuous coverage in hot spotsThe features of continuous coverage in hot spots are:– Limited traffic-absorbing capability, and frequent multiband handover

– High requirements for locating traffic hot spots

– Irregular BTS distribution, which causes difficulty in frequency planning and networkoptimization

– Difficulty in construction and maintenance

– Site construction in densely-populated areas with stepwise coverage and investmentefficiency

l Sparse coverage in hot spotsThe features of Sparse coverage in hot spots are:– Low traffic-absorbing capability, and frequent multiband handover

– High requirements for locating traffic hot spots



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– Irregular BTS distribution, which causes difficulty in frequency planning and networkoptimization

– Difficulty in construction and maintenance

– Small initial investment

5.3.5 Multiband Network TopologyThis describes the multiband networking mode. The networking mode for a multiband networkis of three types: independent MSC networking, Co-MSC/independent BSC networking, andCo-BSC networking. The former two types are referred to as independent networking, and thelatter one is referred to as hybrid networking.

Independent MSC Networking

In independent MSC networking mode, the GSM850 band, GSM900 band, DCS1800 band, andGSM1900 band use different MSCs respectively. Figure 5-2 shows this networking mode wherethe commonly used GSM900 band and the DCS1800 band are applied.

Figure 5-2 Independent MSC networking mode

DCS1800GSM900

MS

BTS

BTS

BSC

OMC

SMC

MSC/VLR

BTS

BTS

BSCMS MSC/VLR

EIR

HLR/AUC

The features of independent MSC networking mode are as follows:

l No impact on the existing network.

l Convenient for network planning and data configuration. The network deploymentbecomes easy.




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l Frequent inter-office handovers and location updates burden the signaling links.

l Requirements are met for capacity expansion in the long term.

l Convenient for network management and service development.

l Cooperation of equipment from different manufacturers is required.

l The initial investment of network deployment is relatively huge. But the average investmenton a user is the lowest.

Due to the previously mentioned features, the independent MSC networking mode outperformsthe hybrid networking mode in the long term.

Co-MSC/Independent BSC Networking

In Co-MSC/independent BSC networking mode, the GSM850 band, GSM900 band, DCS1800band, and GSM1900 band use the same MSC but different BSCs. Figure 5-3 shows thisnetworking mode where the commonly used GSM900 band and the DCS1800 band are applied.

Figure 5-3 Co-MSC/independent BSC networking mode

DCS1800GSM900

MS

BTS

BTS

BSC

OMC

SMC

BTS

BTS

BSCMS

MSC/VLR

EIR

HLR/AUC

The features of Co-MSC/independent BSC networking mode are as follows:

l Certain Impact on the existing network.

l NSS re-planning is required. The network deployment is difficult.

l Inconvenient for capacity expansion and network evolvement.



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l The initial investment of network deployment is relatively small. The average investmenton a user is relatively low.

l The competition among candidate equipment manufacturers is introduced, which helpsreduce the investment and improve the service quality.

l The independent BSC has a backup and the network security is guaranteed.

Co-BSC Networking

In Co-BSC networking mode, the GSM850 band, GSM900 band, DCS1800 band, and GSM1900band use the same BSC, or, the multiband BTSs are connected to the BSC. Figure 5-4 showsthis networking mode where the commonly used GSM900 band and the DCS1800 band areapplied.

Figure 5-4 Co-BSC networking mode

DCS1800GSM900

MS

BTS

BTS

OMC

SMC

BTS

BTS

MS

MSC/VLR

EIR

HLR/AUC

GSM900/DCS1800

BTS

BTS BSC

BSC

The features of Co-BSC networking mode are as follows:

l Possible huge impact on the existing network. The impact may be very serious in case ofa small-capacity BSC.

l NSS re-planning and BSS re-planning are required. The network deployment is difficult.

l Inconvenient for capacity expansion and network evolvement.

l Inconvenient for service development.




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l The competition among candidate equipment manufacturers cannot be introduced. It isunlikely to cut down the investment and improve the service quality.

5.3.6 Technical PrinciplesThis describes the technical principles related to the multiband network. Based on the principles,you need to correctly configure related parameters at the network enabling stage to ensure theperformance of the multiband network.

MS ClassmarkIn the GSM system, MS classmark indicates the service capability, supported bands, powercapability, and encryption capability of an MS.

MS classmark is of three types, namely, Classmark 1, Classmark 2, and Classmark 3. Theinformation contained in Classmark 3 is for multiband applications. The equipment in amultiband network is required to support related handling of MS classmark.

The network learns the capabilities of an MS by querying the MS classmark. Alternatively, thenetwork sets ECSC to require the MS to report its classmark after the link establishment.

Huawei GSM equipment supports the functions such as early classmark sending control (ECSC),and handling of Classmark 3.

BCCH Allocation TableIn the GSM system, the BCCH Allocation (BA) table is a list of BCCH frequencies of all theneighbor cells.

The network sends the MS the BA table in system information, enabling network compatibilityfor the MSs. Thus, the MSs can access the multiband network and perform handoversuccessfully.

The BA table is of the following two types:

l BA1 TableBA1 table lists the neighbor cells for the MS in idle mode. BA1 table is sent in systeminformation type 2, 2bis, and 2ter, which are regularly broadcast by the network on theSACCH to all MSs for cell reselection in idle mode.

l BA2 TableBA2 table lists the neighbor cells for the MS in busy mode. BA2 table is sent in systeminformation type 5, 5bis, and 5ter, which are regularly broadcast by the network on theSACCH to all MSs for handover in busy mode.

While the MS is in busy mode, the MS cannot extract parameters related to neighbor cells fromsystem information type 2, 2bis, and 2ter. Instead, the MS in busy mode extracts the BA tablefrom system information type 5, 5bis, and 5ter, which are regularly broadcast on the SACCH,to ensure the handover procedure. The BA table in system information type 5, 5bis, and 5ter canbe identical with or different from that in system information type 2, 2bis, and 2ter, dependingon the specific network conditions.

The settings of the BA table should be based on network design requirements and actual neighborcells. Otherwise, the network performance may be degraded. Improper handover, improper cellreselection, or even unsuccessful handover may occur.

The number of neighbor cells in every BA table should be less than 32.



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System Information Support to Multiband NetworkThe network sends the MS system information (system information type 2, 2bis, 2ter, 5, 5bis,and 5ter), enabling network compatibility for the MSs. Thus, the MSs can access the multibandnetwork and perform handover successfully.

Huawei 900/1800 system implements full compatibility handling on Phase I and Phase IIGSM900 MSs, Phase I and Phase II DCS1800 MSs, and multiband MSs. The system supportssystem information type 2, 2bis, 2ter, 5, 5bis, and 5ter.

The inter-band frequencies in the neighbor cell list are sent in system information type 2ter and5ter for the multiband MSs.

The Phase I MSs identify only the codes in bit map mode. Therefore, the intra-band frequenciesof GSM900 cells can be encoded in bit map mode in system information type 2 and 5. Thus, thePhase I GSM900 MSs are applicable in the GSM900 cells.

After the encoding, the intra-band frequencies in the GSM1800 cells cannot be sent on one BAtable. Therefore, the codes of the intra-band frequencies are sent in system information type 2and 5, and system information type 2bis and 5bis respectively. System information type 2bis/5bis is for single-band DCS1800 MSs and multiband MSs.

The equipment in a multiband network is required to support system information type 2ter and5ter.

Early Classmark Sending Control (ECSC)ECSC indicates whether the network requires the MS to report MS classmark information(containing Classmark 3) as early as possible. Huawei recommends that you set ECSC to 0 ina single-band network, and set ECSC to 1 in a multiband network to reduce the signaling traffic.ECSC is sent in system information type 3.

Multiband ReportMultiband Report is the information about six neighbor cells of different bands reported bythe MS to the network.

l In a single-band network, the MS reports the measurement results of six best neighbor cellswithin a band.

l In a multiband network, the operator may hope that the MS camps on a certain bandpreferentially when a handover occurs. Therefore, the operator requires the signal strengthand the frequency band in the measurement reports sent by the MS.

In a multiband network, the propagation loss of the DCS1800 band is greater than that of theGSM900 band. Thus, no DCS1800 cells exist in the list of six best neighbor cells reported bythe MS. As a result, the traffic volume absorbed by the DCS1800 network becomes decreased.Through the setting of Multiband Report, the network can require the multiband MS to sendthe Multiband Report of neighbor DCS1800 cells. With different values of MultibandReport, the MS can report the information about neighbor cells of different bands as requiredwhen the MS reports Multiband Report of the six best neighbor cells to the network.

Cell SelectionWhile in idle mode, an MS implements the cell selection and reselection procedures. Thenetwork can control these procedures to balance the distribution of traffic volume.




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When an MS is switched on, it performs cell selection to specify a cell to camp on.

The principles for cell selection are as follows:

l Preferentially select the cell that is accessible and has high priority.

l In case the equal priority, select the cell with the highest value of C1. C1 of the selectedcell must be greater than zero.

NOTE

C1 is defined by the formula:

.

l RXLEV_ACCESS_MIN: Its value range is 0–63, with 0 indicating –110 dBm and 63 indicating –48dBm.

l MS_TXPWR_MAX_CCH: Its value range is as follows:

l GSM900 band: 0–19, with 0 indicating 43 dBm and 1 indicating 41 dBm. Power levels can bestepped up or down in step of 2 dB.

l DCS1800 band: 0–15, with 0 indicating 30 dBm and 1 indicating 28 dBm. Power levels can bestepped up or down in step of 2 dB.

In a multiband network, the propagation loss of the DCS1800 band is greater than that of theGSM900 band. To enable the MS to access a DCS1800 cell, set CBQ (Cell Bar Qualify) andCBA (Cell Bar Access) to control the cell priority.

Table 5-5 lists the cell priority for cell selection and reselection.

Table 5-5 Cell selection/reselection priority

Cell_Bar_Qualify

Cell_Bar_ Access Cell Selection Cell Reselection

0 0 Normal Normal

0 1 Forbidden Forbidden

1 0 Low Normal

1 1 Low Normal

Generally, the settings of cell selection are as follows:

l GSM900 cell: CBQ = 1, CBA = 0.

l DCS1800 cell: CBQ = 0, CBA = 0.

Because the signal strength in a DCS1800 cell is usually weaker than that in a GSM900 cell, thepriority of the DCS1800 cell is set to Normal, and the priority of the GSM900 cell is set to Low.Thus, a multiband MS preferentially selects the DCS1800 cell.

Cell ReselectionUpon completion of cell selection, the MS camps on the selected cell and starts to measure thereceive levels of BCCH carriers for the six strongest non-serving carriers. In addition, the MSextracts various system information and control messages from the six best neighbor cells.



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When certain conditions are met, an MS leaves the serving cell and camps on another cell. Thisprocedure is called cell reselection. The conditions for cell reselection include many factors suchas cell priority, cell accessibility, and radio channel quality.

The reselection criterion C2 indicates the channel quality standard. The value of C2 is definedby the following formula:

l If PT < 31, C2 = C1 + CRO – TO x H (PT – T)

l If PT = 31 (all 1s), C2 = C1 – CRO

NOTE

The meaning of function H(x) is:

l If x < 0, (PT – T < 0), H(x) = 0.

l If x ≥ 0, (PT – T = 0), H(x) = 1.

The principle for cell reselection is to select the cell with the highest value of C2 as the servingcell.

The value of C2 is equal to C1 plus an additional offset parameter. The offset parameter is usedto enable the MS to preferentially camp on certain cells or to hinder the MS from camping oncertain cells. The purpose is to balance the traffic volume.

PI (Cell Reselect Parameters Indication) notifies the MS whether to use C2 as the parameter ofcell reselection and whether associated parameters in the C2 formula exist.

The parameters in the C2 formula are as follows (except C1):

l CRO: an offset applied to the C2 reselection criterion.

l TO (Cell Reselect Temporary Offset): a temporary offset to the C2 reselection criterion.This offset is valid only for a certain duration. The duration is specified by PT.

l PT: Penalty Time

l T (Timer): The initial value is zero. When a cell is placed by the MS on the list of sixstrongest carriers, T is started from zero for the cell with an accuracy of a TDMA frame(about 4.62 ms). When the cell is removed by the MS from the list of six strongest carriers,T for the cell is reset.

PI and associated parameters in the C2 formula can be read from system information type 4, 7,and 8. ACS notifies the MS of the place to extract associated parameters for cell reselection.

l If the MS finds that the value of C2 for a neighbor cell (being in the same location area asthe serving cell) exceeds the value of C2 for the serving cell for a period of 5 seconds, theMS initiates a cell reselection and camps on the neighbor cell.

l If the MS finds that the value of C2 for a neighbor cell (being in a different location area)exceeds the value of C2 for the serving cell by at least CELL_RESELECT_HYSTERESISdB as defined by the BCCH data from the current serving cell, for a period of 5 seconds,the MS initiates a cell reselection and camps on the neighbor cell.

Cell reselection caused by C2 does not take place if there is a cell reselection within the previous15 seconds.

Parameter Reconfiguration for Cell ReselectionTo ensure the network performance, you need to reconfigure certain parameters for cellreselection based on the practical application.




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l For a cell with high traffic volume or with low service quality, try to prevent the MSs fromcamping on the cell. In this case, set PT to 31. Accordingly, the value of C2 for the cell isreduced, making it more difficult for an MS to access the cell. In addition, properly setCRO. When CRO increases, it becomes more difficult for an MS to access the cell.

l For a cell with small traffic volume or with low equipment utilization ratio, try to enablethe MS to camp on the cell. In this case, set CRO to a value from 0 dB to 20 dB. Properlyset CRO. The greater the CRO is, it becomes more easy for an MS to access the cell. SetTO to be equal to or slightly greater than CRO. Set PT to 20 seconds or 40 seconds.

l For a cell with medium traffic volume, set CRO to 0 and therefore C2 is equal to C1. Nooffset is applied to C2.

NOTE

l The value of the CRO should always be less than 25 dB to avoid any uncertainties to the network.

l The parameter configuration is cell-specific. The character of C2, however, is closely associated withneighbor cells. Therefore, the relation between the serving cell and neighbor cells must be consideredfor parameter configuration.

5.3.7 Traffic Guiding StrategyThis describes the traffic guiding strategy of the multiband network. To meet the increasinglyhigh requirements on capacity and quality of the multiband network, the DCS1800 band isrequired to absorb or share the traffic volume at a maximum extent.

The principles of the traffic guiding strategy are as follows:

l In initial stage of network construction, the DCS1800 cells should absorb the traffic volumeas much as possible.

l In hot spots of the DCS1800 network, continuous coverage should be implemented.

l When the number of multiband users reaches a certain level, every band should share theburden of traffic volume to reduce handovers.

The operator can use different traffic control strategies by adjusting related parameters in realtime. The traffic control strategy also depends on the state of the MS.

l While in idle mode, an MS implements the cell selection and cell reselection procedures.When these procedures are performed, system parameters can be set to make a DCS1800cell have a higher priority or a better comparison value of the neighbor cell measurement.Therefore, the DCS1800 cell tends to be the serving cell of multiband users, and the MScamps on the DCS1800 cell before the call establishment procedure.

l While an MS is in a call establishment procedure, the traffic volume assignment can beadjusted through directed retry.

l While an MS is in conversation mode, cell layer and cell hierarchy are set to make thetraffic volume flow to the DCS1800 cell with low layer and high hierarchy.

l In additional, multiband traffic handover can be used to balance the traffic load of the cell.

Cell Selection and ReselectionC1 indicates the quality of the radio channel. The greater value of C1 indicates the better channelquality. The reselection criterion C2 is modified deliberately. The value of C2 can be adjustedthrough CRO. That is, C2 can be calculated based on CRO, TO, and PT. C2 is used for cellreselection to specify the target service cell. By configuring related parameters such as CRO,you can make the C2 of the DCS1800 cell greater than that of the GSM900 cell. Therefore, even



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if the signal strength of the DCS1800 cell is weaker than that of the GSM900 cell, the MS canstill camp on the DCS1800 cell through parameter configuration.

Based on the requirements on network planning, the parameters related to cell selection andreselection can be configured properly to enable the MS to camp on a DCS1800 cell and toprocess a call with good network quality. Thus, the traffic volume burden of the GSM900 cellscan be relieved.

5.3.8 Enhanced Dual-Band NetworkThis describes the enhanced dual-band network that is an improvement on the existing dual-band network. In the enhanced dual-band network, two co-sited cells with different coverageareas are logically formed into a cell group. One is an overlaid subcell and the other is anunderlaid subcell. The enhanced dual-band network algorithm enables the channel resourcesharing and the cell load balance between the two cells in a cell group.

The handover decision for the overlaid subcell and the underlaid subcell in the cell group isbased on the MR. Figure 5-5 shows the structure of a cell group in the enhanced dual-bandnetwork.

Figure 5-5 Enhanced dual-band cell group

Cell BUnderlaid subcell

Cell A

Overlaid subcell

Cell group

Distance

Cell group

Cell BUnderlaid subcell

Overlaid subcellCell A

Optimized Assignment for AccessIn the case of the MS access to the underlaid subcell, the BSC determines whether the RX levelof the MS is equal to or higher than the overlaid subcell level when the underlaid subcell loadis higher than En Iuo Out Cell General OverLoad Thred. If the RX level of the MS is equalto or higher than the overlaid subcell level and if the overlaid subcell load does not overflow,the BSC assigns to the MS the channel in the overlaid subcell and hands over the MS to theoverlaid subcell through a directed retry procedure. Otherwise, the MS is assigned with thechannel in the underlaid subcell.

l If the congestion occurs in the underlaid subcell, the queuing and preemption proceduresare performed.

l If the MS still cannot be assigned with a channel, the MS performs a cell reselection.

In the case of the MS access to the overlaid subcell, the BSC preferentially assigns to the MSthe channel in the underlaid subcell when the underlaid subcell load is lower than En Iuo OutCell Low Load Thred. Otherwise, the MS is assigned with the channel in the overlaid subcell.




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l If the congestion occurs in the overlaid subcell, the queuing and preemption procedures areperformed.

l If the MS still cannot be assigned with a channel, the MS performs a cell reselection.

Handover due to High Underlaid Subcell Load

When the underlaid subcell load is higher than En Iuo Out Cell General OverLoad Thred, acertain number of users should be handed over to the overlaid subcell for the load balance. Thus,the cell capacity is maximized.

The MSs near the BTS are preferentially handed over to the overlaid subcell to suppress theoverlaid inter-cell interference. This is also to minimize the occurrences of handovers from theoverlaid subcell to the underlaid subcell due to the movement of users.

Handover due to Low Underlaid Subcell Load

When the underlaid subcell load is lower than Out Cell Low Load Thred, the MSs far awayfrom the BTS should be handed over to the underlaid subcell to improve the channel utilizationin the underlaid subcell and to suppress the interference of the overlaid subcell to other cells.

Call Movement Handover in the Overlaid Subcell

For the call on the edge of the overlaid subcell, a call drop tends to occur if the handover is notperformed on the MS. Call movement handover enables the MS to be handed over to the bestcandidate cell (ranked first in the BA table) that is not necessarily the underlaid subcell in thecell group.

5.4 ImplementationThis describes how to configure, verify, and deactivate the multiband network.

5.4.1 Configuring the Multiband NetworkThis describes how to configure the multiband network on the BSC6000 Local MaintenanceTerminal.

5.4.2 Verifying the Multiband NetworkThis describes how to verify the multiband network. You can check whether a call uses themultiband function.

5.4.3 Deactivating the Multiband NetworkThis describes how to deactivate the multiband network on the BSC6000 Local MaintenanceTerminal.

5.4.4 Configuring the Enhanced Dual-Band NetworkThis describes how to configure the enhanced dual-band network on the BSC6000 LocalMaintenance Terminal.

5.4.1 Configuring the Multiband NetworkThis describes how to configure the multiband network on the BSC6000 Local MaintenanceTerminal.



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PrerequisiteThe TRXs configured for the BTS support corresponding frequency bands.

Procedure

Step 1 Add a cell.1. On the Management Tree tab page of the BSC6000 Local Maintenance Terminal, right-

click the target site and then choose Add Cell on the shortcut menu. A dialog box isdisplayed, as shown in Figure 5-6.

Figure 5-6 Adding Cells dialog box

2. Select the target site in the Cell view area, and then click Add Cell. A dialog box isdisplayed, as shown in Figure 5-7.




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Figure 5-7 Add New Cell dialog box

NOTE

The cell bands supported by Huawei BSC are GSM900, DCS1800, GSM900 & DCS1800,PCS1900, and GSM850.The P-GSM900 band, E-GSM900 band, and R-GSM900 band are referred to as the GSM900 band.

3. Select a proper frequency band for the new cell.

Step 2 Configure the cell attributes.1. Click OK in Figure 5-7 to return to the previous dialog box, as shown in Figure 5-8.

Figure 5-8 Adding Cells dialog box (1)

2. Select the new cell in the Cell view area, and then click Next. A dialog box is displayed,as shown in Figure 5-9.



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Figure 5-9 Adding Cells dialog box (2)

3. Click Set Cell Attributes. A dialog box is displayed, as shown in Figure 5-10.




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Figure 5-10 Set Cell Attributes dialog box

4. Set Cell Layer and Cell Priority.5. Click Freq Config. A dialog box is displayed, as shown in Figure 5-11.



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Figure 5-11 Set Cell Frequency dialog box (1)

6. Select proper frequencies for the new cell. See Figure 5-12.

Figure 5-12 Set Cell Frequency dialog box (2)

7. Click OK to return to the dialog box shown in Figure 5-10.8. Click TRX Config. A dialog box is displayed, as shown in Figure 5-13.




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Figure 5-13 Configure TRX Attributes dialog box (1)

9. Click the Frequency Attributes tab, and then double-click the frequency in the AvailableFrequencies area to add the frequency to the Assigned Frequencies area. See Figure5-14.



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Figure 5-14 Configure TRX Attributes dialog box (2)

10. Click OK. The frequency assignment is complete, and a previous dialog box is displayed,as shown in Figure 5-10.

Step 3 Set parameters related to the multiband network.1. Click Idle Mode in Figure 5-10. A dialog box is displayed, as shown in Figure 5-15.




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Figure 5-15 Set Idle Parameter dialog box (1)

2. Click Advanced. A dialog box is displayed, as shown in Figure 5-16.

Figure 5-16 Set Idle Parameter dialog box (2)



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3. In Figure 5-16, set the parameters such as Cell Bar Access, Cell Bar Qualify, CRH, PI,NCC Permitted, CRO (2dB), ACS, TO, and PT(s).

4. Click OK to return to the dialog box shown in Figure 5-10.5. Click Call Control in Figure 5-10. A dialog box is displayed, as shown in Figure 5-17.

Figure 5-17 Set Call Control Parameter dialog box

6. Set ECSC and MBR in Figure 5-17.7. Click OK to return to the dialog box shown in Figure 5-10.8. Click Handover Data in Figure 5-10. A dialog box is displayed, as shown in Figure

5-18.




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Figure 5-18 Set Handover Parameter dialog box

9. Set the handover parameters related to the multiband network in Figure 5-18.

10. After the parameters are set, click OK to return to the dialog box shown in Figure 5-10.

Step 4 Click OK in Figure 5-10 to return to the dialog box shown in Figure 5-9.

Step 5 Click Finish. The configuration is complete.

----End

ExampleTo configure a BTS312 covering the GSM900 band, DCS1800 band, GSM900/DCS1800 band,and GSM850 band, do as follows:

1. Configure the BTS312. The BTS software version must be G3BTS32V302R002C05SP01or later official release.

2. Configure the cell using the GSM900 band. Set Cell Layer to 4, Cell Priority to 1, andTRX to RTRX. Keep cell attributes parameters as default values.

3. Configure the cell using the GSM850 band. Set Cell Layer to 3, Cell Priority to 1, andTRX to TRX. Keep cell attributes parameters as default values.

4. Configure the cell using the GSM900/DCS1800 band. Set Cell Layer to 2, Cell Priorityto 1, and TRX to TRX. Keep cell attributes parameters as default values.



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5. Configure the cell using the DCS1800 band. Set Cell Layer to 1, Cell Priority to 1, andTRX to DTRX. Keep cell attributes parameters as default values.

5.4.2 Verifying the Multiband NetworkThis describes how to verify the multiband network. You can check whether a call uses themultiband function.

Procedure

Step 1 Use an MS (supporting the GSM900 band, DCS1800 band, GSM900/DCS1800 band, andGSM850 band) to perform dialing tests, moving around within the coverage area of the BTS.

Step 2 Check the serving cells and call accesses of the MS in different coverage area of the BTS.

----End

5.4.3 Deactivating the Multiband NetworkThis describes how to deactivate the multiband network on the BSC6000 Local MaintenanceTerminal.

ContextTo adjust the frequency bands supported by a cell, you need to delete the cell, and then configurenew frequency bands and network parameters based on requirements.

Procedure

Step 1 Delete the existing cell.1. On the Management Tree tab page of the BSC6000 Local Maintenance Terminal, right-

click the target cell, and then choose Delete Cell on the shortcut menu. A dialog box isdisplayed, as shown in Figure 5-19.




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Figure 5-19 Deleting Cells dialog box (1)

2. Double-click the target cell in the Cell view area to add the cell to the Cells to bedeleted area, as shown in Figure 5-20.

Figure 5-20 Deleting Cells dialog box (2)

3. Click Finish. The deletion is complete.



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Step 2 Add a cell and configure parameters related to the new cell. For details, refer to 5.4.1Configuring the Multiband Network.

----End

5.4.4 Configuring the Enhanced Dual-Band NetworkThis describes how to configure the enhanced dual-band network on the BSC6000 LocalMaintenance Terminal.

ContextThe procedure for configuring the enhanced dual-band network is the same as that for 5.4.1Configuring the Multiband Network.

Procedure

Step 1 Configure the enhanced dual-band cell.

When you configure the cell attributes, set Cell Type to Enhance Dual Band cell, as shown inFigure 5-21.




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Figure 5-21 Configuring cells attributes

Step 2 Configure the handover data for the enhanced dual-band network.

Click Handover Data as shown in Figure 5-21. A dialog box is displayed. Click Advancedand then select the Enhance dual band data tab to configure the handover data, as shown inFigure 5-22.



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Figure 5-22 Configuring data for the enhanced dual-band network

----End

5.5 Maintenance InformationThis lists the alarms and performance counters related to the multiband network.

Alarms

Table 5-6 lists the alarms related to the multiband network.

Table 5-6 Alarms related to the multiband network

Alarm ID Alarm Name

2180 TRX Band Mismatch ARFCN

2302 CDU Band Mismatch ARFCN Alarm

2586 PBU Band Mismatch ARFCN Alarm

3580 DRU Band Mismatch ARFCN Alarm

4168 ARFCN TRX Type Mismatch

5314 CDU Band Mismatch ARFCN Alarm

Counters

Table 5-7, Table 5-8, Table 5-9, and Table 5-10 list the performance counters related to themultiband network.




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Table 5-7 Incoming internal inter-cell handover measurement per cell

Counter Description

H3200Y Incoming Internal Inter-Cell Handover Requests(SDCCH) (900/850-1800/1900)

H3200Z Incoming Internal Inter-Cell Handover Requests(SDCCH) (1800/1900-900/850)

H3209Y Incoming Internal Inter-Cell Handover Requests (TCH)(900/850-1800/1900)

H3209Z Incoming Internal Inter-Cell Handover Requests (TCH)(1800/1900-900/850)

H3210Y Incoming Internal Inter-Cell Handover Responses(SDCCH) (900/850-1800/1900)

H3210Z Incoming Internal Inter-Cell Handover Responses(SDCCH) (1800/1900-900/850)

H3217Y Incoming Internal Inter-Cell Handover Responses(TCHF) (900/850-1800/1900)

H3217Z Incoming Internal Inter-Cell Handover Responses(TCHF) (1800/1900-900/850)

H3220Y (Failed Incoming Internal Inter-Cell Handovers(SDCCH) (900/850-1800/1900)

H3220Z (Failed Incoming Internal Inter-Cell Handovers(SDCCH) (1800/1900-900/850)

H3229Y (Failed Incoming Internal Inter-Cell Handovers (TCH)(900/850-1800/1900)

H3229Z (Failed Incoming Internal Inter-Cell Handovers (TCH)(1800/1900-900/850)

Table 5-8 Outgoing internal inter-cell handover measurement per cell

Counter Description

H3101Y Outgoing Internal Inter-Cell Handover Requests(Directed Retry) (900/850-1800/1900)

H3101Z Outgoing Internal Inter-Cell Handover Requests(Directed Retry) (1800/1900-900/850)

H3111Y Outgoing Internal Inter-Cell Handover Commands(Directed Retry) (900/850-1800/1900)

H3111Z Outgoing Internal Inter-Cell Handover Commands(Directed Retry) (1800/1900-900/850)



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Counter Description

H3121Y Failed Outgoing Internal Inter-Cell Handovers (DirectedRetry) (900/850-1800/1900)

H3121Z Failed Outgoing Internal Inter-Cell Handovers (DirectedRetry) (1800/1900-900/850)

Table 5-9 Incoming external inter-cell handover measurement per cell

Counter Description

H3400Y Incoming External Inter-Cell Handover Requests(SDCCH) (900/850-1800/1900)

H3400Z Incoming External Inter-Cell Handover Requests(SDCCH) (1800/1900-900/850)

H3409Y Incoming External Inter-Cell Handover Requests (TCH)(900/850-1800/1900)

H3409Z Incoming External Inter-Cell Handover Requests (TCH)(1800/1900-900/850)

H3410Y Incoming External Inter-Cell Handover Responses(SDCCH) (900/850-1800/1900)

H3410Z Incoming External Inter-Cell Handover Responses(SDCCH) (1800/1900-900/850)

H3417Y Incoming External Inter-Cell Handover Responses(TCHF) (900/850-1800/1900)

H3417Z Incoming External Inter-Cell Handover Responses(TCHF) (1800/1900-900/850)

H3418Y Incoming External Inter-Cell Handover Responses(TCHH) (900/850-1800/1900)

H3418Z Incoming External Inter-Cell Handover Responses(TCHH) (1800/1900-900/850)

H3420Y Failed Incoming External Inter-Cell Handovers(SDCCH) (900/850-1800/1900)

H3420Z Failed Incoming External Inter-Cell Handovers(SDCCH) (1800/1900-900/850)

H3429Y Failed Incoming External Inter-Cell Handovers (TCH)(900/850-1800/1900)

H3429Z Failed Incoming External Inter-Cell Handovers (TCH)(1800/1900-900/850)




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Table 5-10 Outgoing external inter-cell handover measurement per cell and dual-band handovermeasurement per cell

Counter Description

H3301Y Outgoing External Inter-Cell Handover Requests(Directed Retry) (900/850-1800/1900)

H3301Z Outgoing External Inter-Cell Handover Requests(Directed Retry) (1800/1900-900/850)

H3311Y Outgoing External Inter-Cell Handover Commands(Directed Retry) (900/850-1800/1900)

H3311Z Outgoing External Inter-Cell Handover Commands(Directed Retry) (1800/1900-900/850)

H3321Y Failed Outgoing External Inter-Cell Handovers(Directed Retry) (900/850-1800/1900)

H3321Z Failed Outgoing External Inter-Cell Handovers(Directed Retry) (1800/1900-900/850)

K3170 Dual-Band Handover Requests

K3173 Successful Dual-Band Handovers

5.6 References

l GSM 04.08:"Digital cellular telecommunications system (Phase 2+) ; Mobile radio interface layer 3specification"

l GSM 05.05 (prETS 300 577)"Radio transmission and reception"

l GSM 05.08 (prETS 300 578):"Radio subsystem link control"



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01-05 multiband network- 900-1800mhz

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