Downlink dual carrier.pdf

GSM/EDGE BSS

rel. RG10(BSS), operating documentation, issue 02

Feature description

BSS21228: Downlink dual carrier

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f Important Notice on Product Safety Elevated voltages are inevitably present at specific points in this electrical equipment. Some of the parts may also have elevated operating temperatures.

Non-observance of these conditions and the safety instructions can result in personal injury or in property damage.

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The same text in German:

Wichtiger Hinweis zur Produktsicherheit

In elektrischen Anlagen stehen zwangsläufig bestimmte Teile der Geräte unter Span-nung. Einige Teile können auch eine hohe Betriebstemperatur aufweisen.

Eine Nichtbeachtung dieser Situation und der Warnungshinweise kann zu Körperverlet-zungen und Sachschäden führen.

Deshalb wird vorausgesetzt, dass nur geschultes und qualifiziertes Personal die Anlagen installiert und wartet.

Das System entspricht den Anforderungen der EN 60950 / IEC 60950. Angeschlossene Geräte müssen die zutreffenden Sicherheitsbestimmungen erfüllen.

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Table of contentsThis document has 22 pages.

Reason for update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71.1 In general . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71.2 Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71.2.1 End user benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71.2.2 Operator benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.1 Software requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.2 Hardware requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93.1 Functional overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93.2 Functional split . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93.2.1 BSC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93.2.2 PCU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103.2.3 SGSN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143.2.4 NetAct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143.2.5 Air interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143.2.6 Gb interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4 System impacts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154.1 EGPRS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154.2 High multislot classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154.3 PCU2 pooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154.4 Flexi EDGE dual TRX automatic power down . . . . . . . . . . . . . . . . . . . . . . 154.5 Link adaptation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154.6 DTM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.7 EDA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.8 Extended cell for GPRS/EDGE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.9 Super extended cell for GPRS/EDGE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

5 User interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175.1 Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175.2 MML commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185.3 System responses to failures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185.4 Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195.5 Measurements and counters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195.5.1 25 - TBF observation for GPRS trace measurement . . . . . . . . . . . . . . . . . 195.5.2 27 - GPRS cell reselection observation measurement . . . . . . . . . . . . . . . . 195.5.3 28 - GPRS Rx level and quality observation measurement . . . . . . . . . . . . 195.5.4 72 - PCU measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195.5.5 73 - RLC blocks per TRX measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . 205.5.6 90 - QoS measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205.5.7 96 - GPRS Rx level and quality measurement . . . . . . . . . . . . . . . . . . . . . . 20

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6 Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 – Z . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

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List of tablesTable 1 Software requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Table 2 Hardware requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Table 3 DLDC terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Table 4 Maximum number of DL timeslots allocated for a DLDC-capable MS . 12Table 5 Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Table 6 Counters of the “TBF observation for GPRS trace” measurement . . . . 19Table 7 Counters of the “PCU” measurement . . . . . . . . . . . . . . . . . . . . . . . . . . 20Table 8 Counters of “QoS” measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

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Reason for update

Reason for update

Issue history

Details–

Issue number

Date of issue Reason for update

01 12/2008 Approved draft of first issue for new release

1-1 03/2009 First issue for new release

1-2 06/2009 Update of recommended parameter values

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BSS21228: Downlink dual carrier Introduction

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1 Introduction

1.1 In generalThe “Downlink dual carrier” (BSS21228) feature enables the possibility to allocate radio slots in two parallel separate downlink carriers to one user in the same BTS.

With this feature, the resources of an EGPRS downlink TBF can be assigned to a mobile station on two TRXs.

The feature introduces new (EGPRS) multislot capabilities. Additionally, new MS hardware is required.

DLDC enables higher data rates by doubling the number of timeslots available to a user. For example, a multislot class 30 MS is capable of up to 10 downlink timeslots, i.e. five on each carrier in a 5+5 dual carrier configuration.

The “Downlink dual carrier” feature operates under a TRX capacity license key. It is a 3GPP Release 7 feature.

1.2 BenefitsThis feature has benefits for both the end user and the operator.

1.2.1 End user benefitsThe end user benefits from services of a better quality, at a level comparable to WCDMA/HSPA. Examples include video streaming, file download and web surfing.

End users can enjoy HSPA service level continuity in all (or wider) areas, by being offered twice the throughput compared to (normal) EGPRS (i.e. on single carriers).

1.2.2 Operator benefitsThe “Downlink dual carrier” feature significantly increases resource efficiency (accord-ing to simulations, up to 160%) due to trunking gain.

The operator gains from increased revenues by being able to offer throughput at a level comparable to WCDMA/HSPA.

Using the “Downlink dual carrier” solution, HSPA operators can offer service continuity for the rapidly increasing use of their HSPA services.

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Requirements

2 Requirements

2.1 Software requirementsThe “Downlink dual carrier” feature requires the following software:

2.2 Hardware requirementsThe “Downlink dual carrier” feature requires the following hardware:

Network element Software release required

BSC S14

MS GPRS/EDGE capable Rel. 7 with DLDC support

NetAct OSS5.1 CD2

Table 1 Software requirements

Network element Hardware required

BTS DLDC requires either the MetroSite, UltraSite or Flexi EDGE BTS. MetroSite and UltraSite should have EDGE-capable TRX hardware.

BSC PCU2 plug-in units

Table 2 Hardware requirements

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BSS21228: Downlink dual carrier Functional description

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3 Functional descriptionThis chapter is divided into the following sections: • “Functional overview” • “Functional split”

3.1 Functional overviewThe “Downlink dual carrier” feature offers a possibility to enhance the data rates of DLDC-capable MSs by increasing the number of radio timeslots that can be allocated for the downlink TBFs of such mobiles. This is achieved by assigning the resources of an EGPRS downlink TBF on two TRXs. One of these channels can be e.g. on a BCCH carrier, and the other on a TCH with frequency hopping. The MS receives both radio fre-quency channels, thus doubling downlink throughput. An uplink TBF, on the other hand, is assigned on one TRX only. However, the UL TBF can be dynamically reallocated between the two TRXs to maximize utilization of uplink resources. This feature doubles downlink peak throughput, bringing rates of up to 592 kbps. The average throughput can exceed 300 kbps, enabling e.g, the streaming of high quality video.

DLDC activation is done per BTS. In order to enable DLDC in a BTS, EGPRS must be enabled, and the DLDC license must have enough capacity available.

“Downlink dual carrier” is only supported by the PCU2.

The following terms are used in this document:

3.2 Functional splitThis section describes the impacts of the “Downlink dual carrier” feature on interfaces and network elements.

3.2.1 BSCThe BSC manages licensing, activation and configuration of the feature. The DLDC feature activation is done per BTS.

Term Description

DLDC-activated BTS A DLDC-configured BTS in which the two TRXs are handled by the same DSP in the PCU.

DLDC-capable TRX A TRX of a DLDC-configured BTS.

DLDC-capable TRX pair Two DLDC-capable TRXs.

DLDC configuration Resources of an EGPRS downlink TBF assigned to a mobile station on two TRXs.

DLDC-configured BTS A DLDC-enabled BTS in which two TRXs are in one EDAP so that the EGPRS territory is allowed to extend to the two TRXs.

DLDC-enabled BTS A BTS in which the DLDC feature is enabled.

Table 3 DLDC terms

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Functional description

EGPRS must be enabled and enough capacity in the DLDC license must be available in order to activate DLDC. The default EGPRS capacity must be configured on two TRXs which are in the same EDAP, in order to serve DLDC-capable mobile stations with a DLDC configuration.

The “High multislot classes in BSC” feature must be enabled in order to exploit the extended multislot capabilities of MSs with multislot classes 30-45 for DLDC.

Configuration managementDLDC is enabled with the new BTS-level parameter, “DLDC enabled (DCENA)”. The new BTS and PCU level output parameters show whether or not the PCU is updated after the DCENA parameter is modified. With the new MML command territory downgrade, EDAP table update and territory upgrade for the whole PCU is performed. After the command is successfully executed, the PCU is up to date. This is evident from the new “PCU up to date (PUTD)” parameters of the PCU and BTS.

In order to distribute DSPs over EDAPs in a DLDC-favorable way on the PCU2-U/D, the DLDC-enabled BTSs are automatically upgraded first during those operations that upgrade all the PS territories of the PCU.

EGPRS territory for DLDC

g For a DLDC configuration with an MS, two TRXs must be configured to default packet territory; those TRXs must belong to the same EDAP and must be handled by the same DSP in the PCU. It is the operator's responsibility to configure the suitable EDAPs for DLDC. The PCU-internal DSP allocation functionality tries to automatically maintain the suitable DSP allocations for DLDC.

The operator parameters are considered. In order to maintain the possibility for DLDC configurations from the beginning of the EGPRS territory, the default EGPRS capacity is selected from an EDAP that contains two or more TRXs. Again, in order to maintain the highest amount of TRX pairs for DLDC configurations, when a new TRX is to be upgraded into the EGPRS territory, it should preferably be selected from the same EDAP as the latest (so far) TRX in the EGPRS territory.

3.2.2 PCUThe PCU maintains the DLDC-enabled EGPRS territories for DLDC TBFs. The two TRXs needed for DLDC configuration should preferably be in the same DSP in the PCU, in order to serve DLDC-capable mobile stations. The PCU also manages the DLDC TBFs with MSs.

EDAP/DSP resource management

g Nokia Siemens Networks recommends that every TRX of a DLDC-enabled BTS be attached to the same EDAP.

In PCU2-E, an EDAP is handled with one DSP, and therefore DLDC configurations are possible with every TRX pair of a DLDC-enabled BTS in the EDAP. In PCU2-U/D, an EDAP may not be handled with one DSP only, and therefore DLDC configurations may not be possible with every TRX pair of a DLDC-enabled BTS in the EDAP.

Radio resource management for DLDC-capable MSsWhen an MS indicates DLDC capability, the BSC takes this into account when selecting the radio resources for the MS.

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Resource selection for a TBF involves two main operations: first, which of the BTSs serving the cell would offer the highest capacity is estimated, and then radio timeslots are allocated for the MS from the selected BTS. DLDC is not given absolute priority in either operation, but instead the BTS and the radio timeslots estimated to offer the best throughput for the MS are selected, regardless of whether these offer DLDC or single carrier resources.

BTS selectionBTS selection is done among those BTSs of the cell for which adequate signal levels are measured, and whose frequency band is supported by the MS. The selection is based on finding, for each applicable BTS, the TRX offering the highest PS capacity, and then choosing the best TRX (and hence BTS) from these. The capacity offered by a TRX depends on the territory type supported by the TRX (GPRS or EDGE), the number of PS timeslots configured in the TRX, and the existing traffic loads on these timeslots.

When a BTS is being selected for a DLDC-capable MS, the capacities offered by all possible pairs of DLDC-capable TRXs are included in the selection. That is, if a pair of DLDC-capable TRXs is estimated to offer a higher capacity than any single TRX within a BTS, this pair is selected for comparison with other BTSs, and then the highest capacity BTS is selected, regardless of whether this capacity is offered by a pair of TRXs or by a single TRX.

It should be noted that, although DLDC is not applicable to UL TBFs, the capacities offered by DLDC TRX pairs are considered also when selecting a BTS for a UL connec-tion of a DLDC-capable MS. DLDC-activated BTSs are therefore somewhat favored in anticipation of the DL TBF creation, which is likely to follow the creation of a UL TBF.

If two BTSs are estimated to provide equal capacity, the one with a larger PS territory is selected. In case the territory sizes also match, a DLDC-activated BTS is preferred over a non-DLDC-capable BTS.

Furthermore, when a DL TBF concurrent to a UL TBF is being created for a DLDC-capable MS, the PCU repeats BTS selection if the existing UL resources are from a BTS which is not DLDC-activated.

Channel allocation As in the previous releases, the MS-specific and territory-specific factors affecting the number of timeslots that may be allocated for a TBF in a given direction are: • The multislot class of the MS. • In case of concurrent TBFs, the number of slots allocated in the opposite direction. • The size of the PS territory in the selected BTS.

The BSC supports DLDC for MS multislot classes 8, 10, 11, 12 and 30-45. The BSC also supports so-called “DLDC equivalent multislot classes”, which allow the application of multislot class 30, 31, 32 or 33 characteristics, respectively, in DLDC resource allocation for an MS indicating multislot class 8, 10, 11, or 12, together with an MSCR of 0 or 1.

In principle, the maximum number of DL timeslots that may be allocated for a DLDC TBF is twice the maximum number of DL timeslots supported by the BSC for the MS multislot class in single carrier configuration. In practice, however, the picture is somewhat altered by the fact that an MS may restrict the maximum number of DLDC slots by indi-cating an MSCR greater than zero, and by the support by the BSC of the “DLDC equiv-alent multislot classes”.

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“Table 4” summarizes the maximum number of DL timeslots that may be allocated for a DLDC-capable MS. The “Maximum timeslots per DLDC TRX” column indicates the maximum number of DL slots which may be allocated on each of the two TRXs accom-modating a DLDC TBF, while the “Maximum timeslots per DLDC TBF with MSCR” column indicates, for each possible value of MSCR, the maximum total of DLDC timeslots on two TRXs. It should be noted that the “Equivalent multislot classes” and MSCR are applicable only to DLDC TBFs, and “Table 4” should not be used in reference to single carrier TBFs.

The restriction on the maximum number of DL slots per TRX follows from a requirement that the UL resources allocated for an MS with a DLDC TBF restrict on both DLDC TRXs (regardless of the TRX accommodating the UL resources) the number of DL timeslots, and the position of these in relation to the slots used for UL traffic, as defined by the MS multislot class restrictions.

For concurrent TBFs, the number of DLDC timeslots that may be allocated is therefore affected on both DLDC TRXs by the number of slots allocated for the UL TBF. For

Signalled multislot

class

Maximum timeslots per DLDC

TRX

Maximum timeslots per DLDC TBF with MSCR

0 1 2 3 4 5-6

8 5 10 9 8 7 6 5

10 5 10 9 8 7 6 5

11 5 10 9 8 7 6 5

12 5 10 9 8 7 6 5

30 5 10 9 8 7 6 6

31 5 10 9 8 7 6 6

32 5 10 9 8 7 6 6

33 5 10 9 8 7 6 6

34 5 10 9 8 7 6 6

35 4 8 8 8 7 6 6

36 4 8 8 8 7 6 6

37 4 8 8 8 7 6 6

38 4 8 8 8 7 6 6

39 4 8 8 8 7 6 6

40 5 10 10 10 9 8 7

41 5 10 10 10 9 8 7

42 5 10 10 10 9 8 7

43 5 10 10 10 9 8 7

44 5 10 10 10 9 8 7

45 5 10 10 10 9 8 7

Table 4 Maximum number of DL timeslots allocated for a DLDC-capable MS

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instance, if a two-timeslot UL TBF has been created for an MS class 33 DLDC-capable MS, only four slots per TRX may be allocated for a concurrent DLDC TBF (if MSCR is 0).

Whenever MSCR limits the number of DLDC timeslots that may be allocated for an MS, the BSC restricts the number of slots it allocates on the DLDC TRX that is closer to the border between PS and CS territories. Following the previous example, if the class 33 DLDC-capable MS with a two-timeslot UL TBF indicates MSCR 3, the MS is unable to use more than seven DL slots under any circumstances, and with the UL TBF restricting the maximum number of DL slots per TRX to four, the BSC allocates three slots on the DLDC TRX closer to the PS/CS border, and four on the other.

In DL channel allocation for a DLDC-capable MS, both the best possible DLDC and single carrier resources are identified, after which the better of these is allocated for the MS. As an exception to this, only single carrier DL resources can be allocated concur-rent to an EDA UL TBF.

When no UL TBF concurrent to a DLDC TBF exists, the BSC allocates the PACCH on one of the TRXs accommodating the DLDC TBF, and uses this TRX for polling and RLC control message transmission towards the MS.

When a UL TBF exists concurrently with a DLDC TBF, the PACCH/PTCCH are allo-cated from the same TRX as the resources for the UL TBF.

In case of a concurrent UL TBF allocation, if suitable UL resources are available on both TRXs accommodating a DLDC TBF, the TRX offering the higher UL capacity is selected for the UL TBF.

If an EDA UL TBF is created for an MS with a DLDC TBF, the DL TBF is reallocated as a single carrier connection. Accordingly, when an EDA TBF of a DLDC-capable MS is reallocated as a DA TBF, the possible concurrent single carrier DL TBF may be reallo-cated as a DLDC TBF.

Territory upgradesIf fewer timeslots are allocated for a TBF than could be used by the MS, the BSC adds timeslots into the PS territory in order to allow reallocation of the TBF with the desired timeslot configuration. Such upgrades may be prevented by the CS traffic capacity requirements in the cell.

The same principle is applied to TBFs created for DLDC-capable MSs. However, the desired timeslot configuration depends on whether single carrier or DLDC resources have been allocated for the TBF:

• If single carrier resources have been allocated for the TBF, the target is to allow real-location with as many timeslots as the MS can use in a single carrier configuration.

• If DLDC resources have been allocated for the TBF, the target is to allow realloca-tion with as many timeslots as the MS can use in a DLDC configuration. No upgrade is performed if the PS territory already extends to three or more TRXs.

This approach also means that, following the creation of a DL TBF for a DLDC-capable MS, timeslots may be added to an existing DLDC-territory, but no DLDC-territory is created if one does not already exist.

DLDC TBF reallocationsThe reallocation triggers applicable to single carrier TBFs are also applied to DLDC TBFs.

In addition, a reallocation is triggered for a single carrier TBF created for a DLDC-capable MS in a DLDC-activated BTS, if it is estimated that DLDC resources may

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provide better throughput than the existing resources. Such reallocations are not trig-gered if the MS has a concurrent EDA UL TBF.

Downlink packet transfer in DLDCCommon link adaptation functionality is used for both the carriers of a DLDC TBF. This means that the same MCS is used for both carriers. The following formula is used for selecting the MCS:

MCS = min (MCS on C1, MCS on C2)

For DLDC assignments, a new message format is used. The PCU uses the new message format when the assignment message assigns a dual carrier allocation to a DLDC-capable MS. The PCU uses the new message format also when the assignment message assigns a single carrier allocation to a DLDC-capable MS that has a dual carrier allocation. Otherwise, the old message format is used. For DLDC assignments, the extended RLC/MAC control message segmentation mechanism is used.

3.2.3 SGSNThere is no impact of this feature on SGSN functionality. However, due to DLDC, the “MS RAC” IE is changed.

3.2.4 NetActNetAct supports the new parameters, license, new counters and modified observations related to this feature.

3.2.5 Air interfaceThe impacts of DLDC on the following RLC/MAC control messages are: • Additional MS radio access capabilities • EGPRS packet downlink Ack/Nack • Packet downlink assignment • Packet resource request • Packet timeslot reconfigure • Packet uplink assignment • Packet power control/timing advance • Packet control acknowledgement

3.2.6 Gb interfaceThe “MS RAC” IE in the following messages is changed: • DL-UNITDATA • RA-CAPABILITY • RA-CAPABILITY-UPDATE-ACK

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BSS21228: Downlink dual carrier System impacts

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4 System impactsThis section describes the dependencies or interactions of the “Downlink dual carrier” feature on other features and functions:

This chapter is divided into the following sections: • “EGPRS” • “High multislot classes” • “PCU2 pooling” • “Flexi EDGE dual TRX automatic power down” • “Link adaptation” • “DTM” • “EDA” • “Extended cell for GPRS/EDGE” • “Super extended cell for GPRS/EDGE”

4.1 EGPRSThis feature depends on EGPRS, as DLDC extends the functionality of EGPRS.

The EGPRS feature must be enabled in order to use this feature.

4.2 High multislot classesThe “High multislot classes in BSC” feature must be enabled in order to allow the allo-cation of 5 DL timeslots on each of the 2 carriers for terminals with high multislot class support.

4.3 PCU2 poolingDLDC is supported in PCU2 pooling. The need for DLDC resources is calculated in PCU2 pooling, when the PCU pool configuration is changed and when the PCU pool configuration is reallocated. The target PCU for a DLDC-capable DAP or segment is selected from the PCU pool's PCUs where the most DSP resources are available.

If there is a mixed PCU2-D/U and PCU2-E PIU configuration in PCU2 pooling, then PCU2-E is preferred for DLDC, if the operator allows this with the DLDC offset for PCU2-E selection parameter (DOP).

4.4 Flexi EDGE dual TRX automatic power downFull co-operation between DLDC and the “Flexi EDGE dual TRX automatic power down” feature is not supported. A DLDC-enabled territory is never moved in order to power down a TRX.

4.5 Link adaptationCommon link adaptation is in use with DLDC. The same MCS is used on both TRXs in the DLDC.

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4.6 DTMDTM and DLDC cannot be simultaneously used for an MS connection. However, the DLDC feature and the DTM feature can both be active at the same time in a segment.

4.7 EDAAn MS cannot have DLDC and EDA TBFs simultaneously. However, the DLDC feature and the EDA feature can both be active at the same time in a segment.

4.8 Extended cell for GPRS/EDGE DLDC and the “Extended cell for GPRS/EDGE” feature cannot be simultaneously used for an MS connection. However, the DLDC feature and the “Extended cell for GPRS/EDGE” feature can both be active at the same time in a segment. However, DLDC is not used in extended area TRXs.

4.9 Super extended cell for GPRS/EDGEDLDC and the “Super extended cell for GPRS/EDGE” feature cannot be simultaneously used for an MS connection. However, the DLDC feature and the “Super extended cell for GPRS/EDGE” feature can both be active at the same time in a segment. However, DLDC is not used in super extended area TRXs.

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BSS21228: Downlink dual carrier User interface

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5 User interfaceThis chapter is divided into the following sections: • “Parameters” • “MML commands” • “System responses to failures” • “Alarms” • “Measurements and counters”

5.1 ParametersThe parameters of the “Downlink dual carrier” feature are listed in “Table 5”.

Name Object Description Range Default value

DLDC offset for PCU2-E selection

(dldcOffsefPcu2e)

BSC This parameter changes the behavior of the PCU selection algorithm if DLDC is in use and there are PCU2 – E and PCU2 – D/U cards in the same pool.

0 .. 80 0

DLDC enabled

(dldcEnabled)

BTS With this parameter you can define whether DLDC is used in the BTS or not.

0 - DLDC is disabled

1 - DLDC is enabled

0

PCU up to date

(pcuUpToDate)

BTS, PCU

With this parameter, the system informs the user whether or not DLDC information is updated to the PCU.

0 (N), 1 (Y) 1

BSC Options

(bscOptions)

- BSC options can be activated or deacti-vated only with MML commands in the BSC.

141 (down-link dual carrier)

-

BTS DLDC TSL balance threshold

(BTS_DLDC_TSL_BALANC_THR)

PCU Defines the threshold for triggering an intra-BTS reallocation for a single carrier DL TBF when DLDC resources are avail-able within the BTS.

0 - 100% 100

FC_MS_B_MAX_DEF_EGPRS

Gb inter-face

Buffering capacity default value.

Default value for MS-specific buffering capacity. This may be used for EGPRS-capable MSs (5 kb).

2000 -65280D

25000D

FC_MS_R_DEF_EGPRS Gb inter-face

This parameter defines the default value for MS-specific leak rate. This may be used for EGPRS-capable MSs. The value is given in bytes/s.

1000 -65280D

15000D(= 120 kbit/s)

Table 5 Parameters

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g Nokia Siemens Networks recommends the following values when applying dual carrier in downlink:

40000 (= 40 kbit) for FC_MS_B_MAX_DEF_EGPRS

40000 (= 320 kbit/s) for FC_MS_R_DEF_EGPRS

25000 (= 200 kbit/s) for FC_R_TSL_EGPRS

5.2 MML commandsThe following command groups and MML commands are used to handle the “Downlink dual carrier” feature:

• The EE command group for BSC parameter handling in the BSC: EEQ, EEO • The EQ command group for BTS handling in the BSC: EQV, EQO • The FX command group for Gb interface handling: FXU, FXY, FXO, FXL • The W7 command group for license and feature handling: W7M, W7I

5.3 System responses to failuresThis feature introduces the following error codes:

FC_R_TSL_EGPRS Gb inter-face

This parameter defines the transmission capacity of one EGPRS timeslot. The value is given in bytes/s.

This parameter is used instead of FC_R_TSL if the segment has EGPRS capability.

1000 -65280D

4500D(= 36 kbit/s)

Name Object Description Range Default value

Table 5 Parameters (Cont.)

Name of error code: option_dldc_not_in_use_ec

Number of error code (D/H): 000B4H

Output: DLDC feature is not in use in BSC

Description: DLDC feature cannot be enabled due to the fact that there is no license installed in the BSC, or the license key has expired.

Name of error code: dldc_capa_lic_exceeded_ec


Output: DLDC capacity license exceeded

Description: Capacity of the DLDC license exceeded.

Name of error code: dldc_without_egprs_ec


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BSS21228: Downlink dual carrier User interface

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5.4 AlarmsThis feature introduces an alarm with the following properties:

5.5 Measurements and countersThe following are the measurements and counters related to the “Downlink dual carrier” feature.

5.5.1 25 - TBF observation for GPRS trace measurementThe counters of the “25 - TBF observation for GPRS trace” measurement are:

5.5.2 27 - GPRS cell reselection observation measurementIn case of a DLDC connection, 027004 TRX ID is the identifier of the TRX of the first carrier.

5.5.3 28 - GPRS Rx level and quality observation measurementIn case of a DLDC connection, 022003 TRX ID is the identifier of the TRX of the first carrier.

The counters (028029 - 028089) represent Rx level and quality values of the TRX of the first carrier.

5.5.4 72 - PCU measurementThe counters of the “72 - PCU” measurement are:

Output: DLDC cannot be enabled without EGPRS enabled in BTS

Description: DLDC cannot be enabled if the EGPRS feature is not in use in the BTS.

Alarm ID: 3504

Alarm: dldc_activation_failure_a

Alarm Text: “DLDC activation failure”

Alarm Description: DLDC has not been properly activated for DLDC TBF in PCU.

Number Name

025315 DLDC FLAG

025316 DLDC CAPABILITY

025317 SECOND TRX ID

Table 6 Counters of the “TBF observation for GPRS trace” measurement

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5.5.5 73 - RLC blocks per TRX measurementSince a DLDC TBF has two TRXs, the DL counters of the “73 - RLC blocks per TRX” measurement are updated for the specific TRX in which the RLC MAC blocks were sent or received.

5.5.6 90 - QoS measurementThe counters of the “90 - QoS” measurement are:

5.5.7 96 - GPRS Rx level and quality measurementIn case of DLDC, the TBF DL counters are updated only for the TRX of the first carrier.

Number Name

072250 REQ 9 TSL DL

072251 REQ 10 TSL DL



072254 ALLOC 9 TSL DL

072255 ALLOC 10 TSL DL

072256 DLDC TSL REQUEST IN DLDC ENABLED CELL

072257 DL TSL REQUEST FOR DLDC CAPABLE MS

072258 DLDC TSL ALLOCATION CREATED

072259 DLDC ATTEMPT FAILED DUE TERRITORY

Table 7 Counters of the “PCU” measurement

Number Name

090013 VOLUME WEIGHTED LLC THROUGHPUT FOR DLDC NUMERATOR

090014 VOLUME WEIGHTED LLC THROUGHPUT FOR DLDC DENOMINATOR

Table 8 Counters of “QoS” measurement

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BSS21228: Downlink dual carrier Abbreviations

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6 Abbreviations

0 – ZBCCH broadcast control channel

BEP bit error probability

BSC base station controller

BTS base transceiver station

CS circuit switched

DA dynamic allocation

DL downlink

DLDC downlink dual carrier

DSP digital signal processor

DTM dual transfer mode

EDA extended dynamic allocation

EDAP EGPRS dynamic Abis pool

EDGE enhanced data rates for global evolution

EGPRS enhanced general packet radio service

GPRS general packet radio service

HSPA high speed packet access

ID identifier

IE information element

LA link adaptation

LLC logical link control

MAC medium access control

MCS modulation and coding scheme

MML man-machine language

MS mobile station

MSCR DLDC multislot capability reduction

PACCH packet associated control channel

PCU packet control unit

PCU2 second generation packet control unit

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Abbreviations

PS packet switched

PTCCH packet timing control channel

RAC radio access capability (MS RAC)

QoS quality of service

RLC radio link control

RNW radio network

RX receiver

SGSN serving GPRS support node

TCH traffic channel

TBF temporary block flow

TRX transceiver (transmitter-receiver)

TSL time slot

UL uplink

WCDMA wideband code-division multiple access

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