fd ru20 feature descriptions 85[1]

8/10/2019 Fd Ru20 Feature Descriptions 85[1]

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WCDMA RAN, Rel. RU20, Feature Descriptions

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1.1.8 RAN1686: HSPA 72 Users Per Cell

1.1.8.1 Introduction to the feature

This feature increases the number of simultaneous HSPA (HSDPA and HSUPA) users

to 72 per cell. Due to this increase, the number of DL HSDPA and HSUPA control

channels is increased. Additionally, dynamic allocation of the DL code space used by

these channels is enhanced.

1.1.8.2 Benefits

End user benefits

With this feature more users can be kept on HSPA, providing an instant access to data

services after momentary inactivity periods and thus improving the end user experience.

Operator benefits

The introduction of this feature creates pre-conditions for support for high number of

voice users over HSPA as well as for support of high number of always on' users on

HSPA.

1.1.8.3 Requirements

Software requirements

Hardware requirements

This feature requires RAN1016/RAN1848: Flexi BTS Multimode System Module or

RAN1671: Enhanced UltraSite Base Band (EUBB).

1.1.8.4 Functional description

This feature allows 72 simultaneous HSPA (HSDPA/HSUPA) users per cell, both with

dedicated and shared scheduler.

In order to be able to schedule and control increased number of HSPA users in a cell,

the number of HS-SCCH channels is increased to four. The maximum number of HS-

SCCH codes are defined by MaxNbrOfHSSCCHCodes parameter. On the other hand,

as the DL code space is a scarce resource, a dynamic DL control channel allocation

mechanism is introduced to maximize the available codes for HS-PDSCHs.

E-HICH/E-RGCH codes are allocated dynamically based on the number of users.

This is done in order to avoid fragmentation of the code space.

RAS RNC BTS Ultra BTS Flexi BTS

Pico

AXC NetAct MSC SGSN MGW UE

Release RU20 RN5.0 WBTS6.0 WBTS6.0 - - OSS5.2 - - - 3GPP

Rel6

Table 26 Software requirements


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The E-HICH/E-RGCH signatures are actively reconfigured.

The number of actually needed E-RGCH/E-HICH codes depends on TTI and RAB

combinations of active UEs.

The code space of HS-SCCH# 2, 3 and 4 code can be dynamically used for the 15thHS-PDSCH, if not needed for HS-SCCH. The HS-SCCH# 2, 3, and 4 are mapped

to the same code tree branch as the last HS-DSCH SF16 code. If this SF16 code

branch is not needed for any other channels, the BTS may use it for HS-DSCH trans-

missions, therefore allowing the full use of the DL HSDPA bandwith.

72 simultaneous HSPA users per cell are supported on Flexi SM2 and EUBB:

The minimum configuration for 72 HSPA users per cell in Flexi SM2 is FSMD

(includes 2xFSPC).

In EUBB subrack minimum 2xWSPF are needed.

In general the maximum number of HSPA users per BTS depends on:

how many LCGs are used

how base band capacity is divided between LCGs

how many HSDPA schedulers are used

what kind of HSPA users they are (SRB on DCH or HSPA)

what are the cell ranges (affects to CEs required for CCH)

The maximum number of simultaneous HSPA users per BTS is 288 for Flexi SM2 and

144 for Ultra EUBB. 288 HSPA users for Flexi SM2 requires 4+4+4 configuration with

two FSME modules and 4 LCGs. 144 HSPA users with Ultra EUBB is achieved with

2+2+2 configuration, with 3 WSPF boards in EUBB subrack and 2 LCGs.

With four LCGs, there is a possibility to reach 288 HSPA users. In this case there would

be 216 HSPA users with SRB on DCH and 72 HSPA users with SRB on HSPA (SRB on

DCH requires one CE per user).

For Flexi SM2 the maximum number of HSPA users per BTS is 144 when one FSME or

two FSMD modules are in use and 2+2+2 configuration is applied.

With 2+2+2, 3+3+3, and 4+4+4 configurations, also the extension module can be used

for HSPA.

With 3+3+3 configuration, the maximum number of HSPA users per BTS depends on

BTS configuration. See the following examples:

example 1

If two LCGs (two carriers in one LCG and one carrier in the other) are used, the

maximum number of HSPA users per BTS is 152 (with 2xFSME). In this case the

maximum number of supported HSUPA users is 160 (80 per LCG). Then it is the

HSDPA configuration that matters:

In LCG having two carriers, there are at least two schedulers supporting up to

144 HSDPA users per LCG, but HSUPA support limits it to 80 UEs.

In LCG having one carrier, there is one scheduler supporting 72 HSDPA users

per LCG, so HSDPA is limited to 72 UEs.

So if configuration is 3+3+3 with HSDPA configuration as defined above, the

maximum number of HSPA users per BTS is 152 (80+72).

example 2

If three LCGs (one carrier per LCG) are used, the maximum number of HSPA users

per BTS is 216 (2xFSME). The limitations in this case are:

Maximum HSUPA UEs per LCG is 80.


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Maximum HSDPA users per LCG is 72.

When those limitations are taken into account, the maximum number of HSPA users

per BTS is 216 (3x72).

In case of configuration 1+1+1 the maximum number of HSPA users per BTS is 80 withFlexi SM2 and Ultra EUBB when all users are allocated to one Local Cell Group. From

the HSDPA scheduler point of view the following options are used:

when users are allocated to two shared schedulers, the number of HSDPA

(HSDPA/DCH) users is 144 and the number of HSPA (HSDPA/HSUPA) users is 80.

when users are allocated to three full baseband schedulers, the number of HSDPA

users is 216 and the number of HSPA users is 80.

The other possibilities in case of 1+1+1 configuration:

When all users are allocated to one HSDPA shared scheduler the number of users

is limited to 72.

When users are allocated to one full baseband scheduler, the number of HSPAusers is 72 with only one cell supported.

When users are allocated to two full baseband schedulers, the number of HSPA

users is 80 with only two cells supported.

For more information on configuration possibilities, see BTS baseband dimensioningin

Dimensioning WCDMA RAN.

The BTS contributes to the de-fragmentation of the code space by actively reconfiguring

the active E-HICH/E-RGCH signatures when possible to a code closer to the beginning

of the code tree.

1.1.8.5 System impact

Interdependencies between features

This feature requires the following features to be activated:

RAN312: Dynamic Resource Allocation

RAN763: Basic HSDPA

RAN826: Basic HSUPA

RAN852: HSDPA 15 codes

Impacts on interfaces

This feature has impact on the following interfaces:

Uu: Higher number of HSPA UEs/Cell - load and interference issues, higher ranges

of UE identifiers like E-RNTI and H-RNTI

Iub: Impact on transport

Management: new classes of HSPA distribution/duration counters

Impacts on alarms

There are no alarms related to this feature.

fd ru20 feature descriptions 85[1]

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