Investigation SecCarrier Strategies RevB

INVESTIGATIONINVESTIGATION

SECOND CARRIER SECOND CARRIER STRATEGIESSTRATEGIES

Study for an operator in Switzerland,Study for an operator in Switzerland,June 2008June 2008

© Ericsson AB 2008 Commercial in confidence Christian MATHIS (Ericsson) 2008-06-182 (53)

CONTENTSCONTENTS

Introduction and overview

Strategy for 2nd carrier

deployment project

Future strategy improvements

Conclusion


IntroductionIntroductionIn H2/2007, there was a strong growth of HSDPA traffic observed in the operator‘s 3G network. In order to provide the capacity for this increasing traffic demand, the existing 3G network needs to be expanded and the introduction of a second WCDMA carrier was proposed.

In April 2008, the operator decided to roll out and optimize the second WCDMA carrier for 145 sites. In the scope of this project, it was proposed to start with a basic strategy, having a limited set of features and parameters involved, to ensure a smooth deployment of the second carrier. The second carrier rollout for those 145 sites will be performed under UTRAN release P5, the upgrade to P6 is scheduled for September 2008.

The strategy was proposed as the first step to introduce the second carrier. Adjustments to this strategy can be done when the traffic demands change.

The investigation in the following summarizes the currently implemented 2nd carrier strategy and possibilities for strategy improvements/enhancements in the future.


Overview: Second Carrier Strategies (1/3)Overview: Second Carrier Strategies (1/3)

HS HS

R99 R99 R99

HS

f1

f2 HS

R99

R99 R99 R99f1

f2

R99

(1) R99 on the first carrier, HSDPA on the second carrier

(2) R99 on the first carrier, R99 & HSDPA on the second carrier

R99/HS R99/HS R99/HS R99/HS



HS HS HS

f1

f2 HS

f1

f2

(3) R99 & HSDPA on the first carrier, HSDPA on the second carrier

(4) R99 & HSDPA on both carriers






+ Highest flexibility for traffic distribution / balance- Many traffic distribution & mobility scenarios ⇒complex and extensive parameterization, limited possibilities to steer traffic distribution in P5 and P6.

R99&HSR99&HS(4)

+ Appropriate strategy when high HS traffic- Challenging to optimize HS traffic distribution

HSR99&HS(3)

+ Appropriate strategy when high R99 traffic- Requires IFHO/IFLS (planning & optimization)

R99R99&HS(2)

+ Smooth implementation involving few new features and parameters(1st step scenario)- Low flexibility for traffic distribution / balance, suboptimal use of capacity

HSR99(1)

Remarks:f2f1*Strategy

* For strategy (1), (2) and (3) f1 is assumed to be the access frequency, i.e. subscribers in idle mode are camped on or do reselection to f1.


CONTENTSCONTENTS



deployment project


Conclusion


StrategyStrategy

Strategy (1) : HSDPA on the second carrier, R99 on the first

In idle mode, all subscribers are on the first carrier. At call setup, HSDPA and R99 traffic are steered to separate carriers, i.e., HSDPA connection requests are directed to the second carrier (blind Hard Handover) whereas R99 connection requests are established on the first carrier.

HS HS

R99/HS R99 R99 R99

HS

R99/HSf1

f2


Strategy Strategy benefitsbenefits

Best possible HSDPA throughputA separate carrier reserved for HSDPA traffic means very good throughput since the HSDPA traffic does not need to share the RBS power with the R99 traffic.

Smooth implementation: Movement of subscribers between carriers is done either during call setup or in idle (cell reselection)

R99 traffic is unaffectedReserving a separate carrier for HSDPA means that the R99 traffic is not affected by the HSDPA deployment.

Future proof (high capacity having two carriers)Two carriers mean twice the capacity. It leaves a margin for future traffic growth.


Strategy Strategy drawbacksdrawbacks

DeploymentDeploying HSDPA on the second carrier involves more parameters (idle mode) to be set than sharing the same carrier with R99 and new neighbor and coverage relations to be defined. Care needs to be taken to avoid R99 UEs to camp on the second carrier.

Hard handover for HSDPA UEsHSDPA users need to be moved to the second carrier by blind HHO. This involves a risk for dropped calls or unsuccessful RRC set-up on the second carrier. The risk for dropped calls or unsuccessful RRC set-ups can be reduced by tuning the parameter hsPathlossThreshold, which determines when the UE is allowed to perform blind HHO to the second carrier. The extra call set-up time for HSDPA due to the blind HHO is limited; HHO contributes with around 0.5 s from a total call set-up time of approximately 2.5 s.

There is low flexibility to distribute and balance R99 and HS traffic to the two carriers. The use of the capacity of the two carriers is suboptimal.

Limited mobility at second carrier coverage border, when „HSDPA Mobility Phase 2“ and „Inter-Frequency Handover“ is not implemented.


Functionality: Idle modeFunctionality: Idle mode

Objective: f1 is the access frequency, in idle mode all users are on f1

R99 traffic: After connection release, the UEs shall camp on the best cell of the last Active Set. HSDPA traffic: After connection release, the UEs shall perform a cell reselection from f2 to the best measured cell on f1.The relevant main parameter is- qOffset2sn, if parameter qualMeasQuantity = „CPICH EcNo“- qOffset1sn, if parameter qualMeasQuantity = „CPICH RSCP“

IMPORTANTThere are UE models not fully compliant to 3GPP standard with the limitation thatInter-Frequency Handover, Inter-Frequency Load Sharing and/or the reselectionparameters qOffsetXsn are not supported / ignored.


Functionality: Dedicated modeFunctionality: Dedicated mode

Objective: R99 users on f1, HSDPA users on f2

R99 traffic: Compared to today‘s configuration (R99 and HS on f1), R99 users should not experience any difference.

HSDPA traffic: At RRC connection setup, all users requesting a HS service perform a Hard Handover from f1 to f2. The service isset up and provided on f2.

HS HS

R99 R99 R99

HS

f1

f2


NeighbourNeighbour parameterparameter definitiondefinition

Coverage relation definition for R99 cells on f1* (with overlaid HS cell):

A) Coverage relation to the overlaid HS cell (same sector)Attributes of Coverage relation:

utranCellRef (target cell)coverageIndicator (with values: Covers; Overlaps; Contained_In)hsPathlossThreshold (15 to 170 dB, a configurable threshold in the candidate cell which has a coverage relation with best cell)

*Definition of neighbour cells is needed for the scenario when both HS and R99 traffic should be transferred to f2 cells.

Neighbour cell definition for HS cells on f2:

1) Direct neighbour cells on f22) Underlaid R99 cell on f1 (same sector)3) For cells at f2 coverage border: Underlaid cells on f1 (supporting R99 and HS).

1)

2)3)

A)


Summary of main parametersSummary of main parameters2nd Carrier2nd CarrierMO Parameter value 1st carrier default valueUtranCell hoType NONE GSM preferred

Hsdsch administrativeState unlocked unlocked (locked)UtranRelation qOffset2sn 0/-10/-20 0

1st Carrier1st CarrierMO Parameter new value old valueHsdsch administrativeState locked unlocked

CoverageRelation utranCellRef cellname -

CoverageRelation coverageIndicator overlap - -CoverageRelation hsPathlossThreshold 170 -

RncFunction hsOnlyBestCell FALSE TRUE


CONTENTSCONTENTS



deployment project


Conclusion


Summary:Summary:Investigations Future Strategy ImprovementsInvestigations Future Strategy Improvements

Investigation of possibilities to introduce mobility f1 ↔ f2 at f2 coverage border.

Proposals to improve HS service retainability (HS service Erl-Min per drop)

Investigation of Multi-RAB user handling

Study of specific features (UTRAN P5 and P6) which can improve the current strategy or supporting future strategies

Comparison of strategy (1) and (3), possibilities to move from strategy (1) to strategy (3)


Mobility limitation at second carrier coverage bordersMobility limitation at second carrier coverage borders

If „HS mobility phase 2“ and „Inter-frequency Handover“ are not configured in the system, there are the following limitations at the coverage border area of f2:

CASE 1: When an active HS user on f2 leaves the f2 coverage area, it will stay on the best f2 HS cell until a connection release is initiated by the system due to poor signal.

CASE 2: When an active HS user on f1 enters f2 coverage area, it will stay on the best f1 HS cell until a connection release is initiated by the system due to poor signal.

CASE 2

CASE 1


Mobility limitation at second carrier coverage bordersMobility limitation at second carrier coverage borders

In general, when the HSDPA connection is dropped, the PDP context is maintained. The PS application attempts to setup a packet call on a new, reselected cell automatically (directed signalling connection re-establishment). However, the subscriber will experience low throughput and also a session outage.

In the Pilot Area of the project, the problem was seen especially alongside railways where most of the moving HS users are assumed.

CASE 2

CASE 1


Improvement of mobility Improvement of mobility at second carrier coverage borders at second carrier coverage borders

Case 1Case 1Description:Introduction of mobility by means of the features „Inter-Frequency Handover“ and Feature „HS Mobility Phase 2“as well as the corresponding parameterization.

HS HS

R99/HS R99 R99f1

f2

Cell 21

Cell 11Cell 12

Functionality:- User in CELL_DCH(HS) on Cell 21

- User leaving f2 coverage area → Poor signal quality Cell 21 →Reconfiguration CELL_DCH(HS) to CELL_DCH(R99) on Cell 21

- Inter-Frequency Handover Cell 21 to Cell 12 in CELL_DCH(R99) state

- Reconfiguration CELL_DCH(R99) to CELL_DCH(HS) on Cell 12


Requirements:- Feature Inter-Frequency Handover

- Feature HS Mobility Phase 2

- Parameterization of (one-way) Inter-Frequency Handover f2 → f1

Remarks:- Active Non-HS users will also benefit from this mobility, but perform directly an Inter-Frequency Handover.

- Drawback: At poor signal quality on f2, all active users will perform a HS → R99 reconfiguration and possibly IFHO to f1, e.g. at poor indoor coverage.


Case 1Case 1HS HS

R99/HS R99 R99f1

f2

Cell 21

Cell 11Cell 12



Case 2Case 2Description:Introduction of mobility by means of the feature „HS Mobility Phase 2“ as well as the corresponding parameterization.

Functionality:- User in CELL_DCH(HS) on Cell 12

- User entering f2 coverage area (leaving HS coverage area on f1 respectively)

- Change of Best Cell for A-DCH from Cell 12 to Cell 11, no HS Cell Change

- Poor signal quality Cell 12 → Reconfiguration CELL_DCH(HS) to CELL_DCH(R99) on Cell 12- Inter-frequency transition (Blind Hard Handover) from Cell 11 (no HS support) to Cell 21 (HS support) using coverage relation- CELL_DCH(HS) on Cell 21

HS HS

R99/HS R99 R99f1

f2

Cell 21

Cell 11Cell 12


Requirements:- Feature HS Mobility Phase 2

- Definition and parameterization of coverage relation f1 → f2

(e.g. Cell 11 to Cell 21)

Remarks:

- When Inter-Frequency Handover from f1 → f2 is not implemented, active non-HS users will not be affected.

- The feature Inter-Frequency Handover could provide further mobility scenarios but also the possibility of (unwanted) handover of R99 traffic from f1 → f2


Case 2Case 2HS HS

R99/HS R99 R99f1

f2

Cell 21

Cell 11Cell 12






Study of specific features (UTRAN P5 and P6) which can improve the current strategy or supporting future strategies.



Improvement of HS service retainability Improvement of HS service retainability (Erl(Erl--Min/drop)Min/drop)

CASE 2

CASE 1

The first step strategy to deploy the second carrier (see p. 7ff) assumes low mobility of the HS users.

In cases where this assumption cannot be applied – e.g. alongside railways where most of the moving HS traffic is assumed – there is an increased number of HS RAB drops/system releases in the border areas, both for HS users on f1 and f2.


Improvement of HS service retainability Improvement of HS service retainability (Erl(Erl--Min/drop)Min/drop)

CASE 2

CASE 1The occurance of HS RAB drops/system releases is reflected in the performance indicator „PS Interactive HS Minutes per Drop“, according to the formula:

NOTE: A corresponding performance indicator is also calculated for CS services (CS Erl-Min/drop). A comparison of this performance indicator for CS and PS is limited: At a drop, a CS user experiences a complete loss of the service; a PS user has – in general - a temporary, severe degradation of the service (low throughput/outage) but no loss of the service.


Analysis Pilot Cluster: HS service retainabilityAnalysis Pilot Cluster: HS service retainability (1/3)(1/3)

Five cells were selected for the analysis of the HS service retainability.

ZH149BU1

ZH205CU1

ZH166BU1

ZH080CU1

ZH166CU1


Analysis Pilot Cluster: HS service retainabilityAnalysis Pilot Cluster: HS service retainability (2/3)(2/3)

The five cells were selected according to the different scenarios:

Border cells on f1, case 2: ZH149BU1, ZH205CU1

Border cells on f2, case 1: ZH080CU1/11, ZH166BU1/11

Core cell on f1/f2, case 3: ZH166CU1

ZH149BU1

ZH205CU1

ZH166BU1

ZH080CU1

ZH166CU1

Railway


The listed Performance Indicators are based on network counters. The f2 core cell ZH166CU11 was the only cell showing a (significant) improvement.

Comment: In general, the PS HS Erl-Min/Drop figures per day showed strong variations due to low number of samples. It could be seen that there were modest HS traffic levels and few samples for HS RAB releases, even over a period of 7 days, resulting in limited statistical expressiveness.

Analysis Pilot Cluster: HS Service retainability PIs (3/3)Analysis Pilot Cluster: HS Service retainability PIs (3/3)


Measures to improve HS service retainabilityMeasures to improve HS service retainability

CASE 2

CASE 1

The proposed introduction of mobility at f2 coverage borders will improve the HS service retainability. With the features „Inter-Frequency Handover“ and „HS Mobility Phase 2“ as well as the appropriate parameterization, the system initiated releases at f2 coverage borders (Case 1 and Case 2) will be eliminated.









Investigation of MultiInvestigation of Multi--RAB user handlingRAB user handling

The following four scenarios were investigated:

Scenario 1: HS connection in f1&f2 coverage area, additional R99 connection

Scenario 2: R99 connection in f1&f2 coverage area, additional HS connection

Scenario 3: Active Multi-RAB user (HS+R99) moving from f1 coverage area to f1&f2 coverage area.

Scenario 4: Active Multi-RAB user (HS+R99) moving from f1&f2 coverage area to f1 coverage area.

(3)

(4)(1) HS → +R99

(2) R99 → +HS


MultiMulti--RAB user handlingRAB user handling

Scenario 1:At connection setup, HSDPA service requests are directed to f2. If there is an additional request of an R99 service, e.g. an incoming voice call during an active HSDPA session, a Multi-RAB HS(PS)+R99(CS) is established on f2.

Scenario 2:At connection setup, R99 service requests are kept on f1. If there is an additional request of a PS service from an HS capable UE, e.g. starting an FTP download during a voice call, and a coverage-related cell is defined towards f2, then a hard handover is attempted to set up a Multi-RAB HS(PS)+R99(CS) on f2. If no coverage relation is defined, a R99(PS)+R99(CS) is established on f1.

Note: The probability for Scenario 1 is much higher than for Scenario 2.


MultiMulti--RAB user handlingRAB user handling

Scenario 3:Without the features „Inter-Frequency Handover“ and „HSDPA Mobility Phase 2“ an active Multi-RAB user (HS+R99) moving from f1 to f1&f2 coverage area will keep the R99 service and release the HS PS connection.

If the features „HSDPA Mobility Phase 2“ and „Inter-Frequency Handover“ are activated with the corresponding parameterization, the Multi-RAB user will be transferred to f2 (see „Mobility, Case 1“, p.21).

Scenario 4:Without the features „Inter-Frequency Handover“ and „HSDPA Mobility Phase 2“ an active Multi-RAB user (HS+R99) moving from f1&f2 to f1 coverage area will release both the R99 service and the HS PS connection.

If the features „HSDPA Mobility Phase 2“ and „Inter-Frequency Handover“ are activated with the corresponding parameterization, the Multi-RAB user will be transferred to f1 (see „Mobility, Case 2“, p.19).

(3)

(4)


Summary MultiSummary Multi--RAB user (HS+R99) handlingRAB user (HS+R99) handlingWithout features „Inter-Frequency Handover“ and „HSDPA Mobility Phase 2“

With features „Inter-Frequency Handover“ and „HSDPA Mobility Phase 2“






Specific features (UTRAN P5 and P6) which can improve the current strategy or supporting future strategies.



Specific features to improve current strategy or Specific features to improve current strategy or supporting future strategiessupporting future strategies

Inter- Frequency Handover and Cell Reselection (FAJ 121 405)

Inter-Frequency Load Distribution (FAJ 121 902)

HSDPA Mobility Phase 2 (FAJ 121 860)

Hierarchical Cell Structures (FAJ 121 1055)

There are also other features involved to a smaller extend in the different strategies and strategy improvements. However, the focus of this investigation was on the most essential features listed above.


InterInter--Frequency Handover and Cell Reselection (1/2)Frequency Handover and Cell Reselection (1/2)

Description:The Inter-frequency handover feature allows for an ongoing call to be transferred from one WCDMA frequency to another in case a UE is moving out of coverage of the source frequency. The feature covers functions for both Inter-frequency handover for UEs on dedicated channel and for inter-frequency cell reselection in connected mode on common channel and in idle mode. The criteria to trigger an Inter-frequency handover can be

• Low Ec/No (signal quality) • Low RSCP (signal strength) • High UE Tx Power

f1

f2

Inter-Frequency Handover


InterInter--Frequency Handover and Cell Reselection (2/2)Frequency Handover and Cell Reselection (2/2)

Benefit for second carrier strategy:Usually, an additional carrier is deployed to provide more capacity. The feature “Inter-Frequency Handover” is crucial to maintain the UE radio connections in a situation where the frequency has to be changed due the poor radio environment (quality, signal strength).

In P6, service-dependent thresholds (per UeRc) are introduced to trigger Inter-RAT or Inter-frequency handovers. This will allow the definition of different coverage areas for different services and provide the possibility to control the traffic distribution between frequencies, e.g. CS and PS traffic.

PS CS CS PS


InterInter--Frequency Load DistributionFrequency Load Distribution (1/2)(1/2)

Description:The main purpose of Inter-Frequency Load Distribution is to divert incoming R99 traffic during connection establishment from a more-loaded cell to a less-loaded one at the same location but on another frequency. The HSDPA serving cell selection algorithm is affected neither by the cell load level nor this feature.

e.g. R99

e.g. R99&HS

(20%)


e.g. R99

e.g. R99&HS

InterInter--Frequency Load DistributionFrequency Load Distribution (2/2)(2/2)

Benefit for second carrier strategy:By means of this feature, R99 traffic can be steered between two frequencies, according to the load levels in the source and target cell. When R99 and HSDPA traffic are allocated on different carriers, this may be used to "free" one or more carriers for HSDPA traffic.In combination with e.g. a Hierarchical Cell Structure deployment, it can be used to push traffic to a specific cell layer.The feature is mainly beneficial for the strategies (2) and (4).


HSDPA Mobility Phase 2 HSDPA Mobility Phase 2 (1/2)(1/2)

Description:“HSDPA Mobility Phase 2” includes several use cases where the service continuity is increased compared to the first HSDPA phase. These are

- Inter-RNC mobility (Iur) - Inter-frequency mobility - Inter-RAT mobility - DCH (HS) to DCH (R99) transition at HSDPA border area - DCH (R99) to DCH (HS) transition at change of best cell in Active Set - Cell_FACH to DCH (HS) transition at service request

The use cases are valid for both PS only connections and PS+CS connections (Multi-RAB) on HSDPA.


HSDPA Mobility Phase 2 HSDPA Mobility Phase 2 (2/2)(2/2)Benefit for second carrier strategy:

“HSDPA Mobility Phase 2” is the most essential feature to provide a high QoS for active and moving HS users, especially at the coverage border areas of the second carrier.In combination with the feature “Inter-Frequency Handover”, the mobility for HS users can further be improved.

Another benefit is the improved handling of Multi-RAB users (HS+R99):


Hierarchical Cell Structures Hierarchical Cell Structures (1/2)(1/2)

Description:This feature is introduced in UTRAN release P6.The feature Hierarchical Cell Structures (HCS) allows to control the camping of UEs in Idle Mode, not only according to best cell (RSCP or Ec/No) but also according to cell hierarchy. The information whether HCS is used or not for Idle Mode UEs is defined in System Information (SIB11).The HCS priority level is defined by an integer between 0 and 7 (Level 0 = lowest priority; level 7 = highest priority).

444


Hierarchical Cell Structures Hierarchical Cell Structures (2/2)(2/2)

Benefit for second carrier strategy:

The HCS feature will allow the operator to steer Idle Mode UEs to a selected frequency layer of cells. This will lead to that the WCDMA RAN can direct the HS capable UEs to the HS capable layer where less R99 UEs and CS-only UEs compete for resources. The benefit of the feature comes from less interfering traffic in the HS layer.As an example, HCS can be used to push all UEs in Idle Mode to the “access frequency layer” that carries R99 traffic only. By means of HCS parameters, this is almost independent of the signal strength and quality on the access frequency layer. Every request for a connection will be started on the access frequency, e.g. f1 in the picture below:

HS HS

R99/HS R99 R99f1

f2 HCS level 5

E.g.

HCS level 2

Idle Mode reselection









Comparison of 2nd carrier strategies (1) and (3)Comparison of 2nd carrier strategies (1) and (3)

HS HS HS

f1

f2 HS

2nd carrier Strategy (1)

R99 R99 R99/HS R99/HS

When a single carrier with combined and balanced R99/HS traffic becomes highly loaded, the 2nd carrier deployment according to strategy (1) is appropriate and sufficient.According to the trend of the traffic demand, it is assumed that there will be a continuing fast growth of HS traffic and a modest growth of R99 traffic.Based on this forecast, it would be beneficial to move from strategy (1) to (3), see also p.4/5, in order to make more flexible and efficient use of the resources at high traffic load.As a consequence, the HS performance could be further optimized.

f1

f2



Possibilities to move from strategy (1) to (3)Possibilities to move from strategy (1) to (3)

HS HS HS

f1

f2 HS


R99 R99 R99/HS R99/HS

Description:The move from strategy (1) to (3) requires the activation of HS on the first frequency.It is quite challenging to steer and optimize the distribution of HS traffic as there are no specific features and limited parameters available in UTRAN release P5 and P6.

f1

f2



Possibilities for traffic distributionPossibilities for traffic distribution (1/2)(1/2)Second carrier strategy (3)Second carrier strategy (3)

Possibilities:A tailored functionality to distribute HS traffic to the different frequencies would be based on throughput and quality experienced by the active HS users as well as resources available on the different frequencies. Such a functionality is not available (yet), the limited possibilities are:

1) Quality based move of HS trafficWhen HS is activated on both frequencies, first the resources will be allocated for HS on the frequency where the users are camped on in Idle Mode (in this case f1). At poor quality on f1, e.g. caused by high load/interference, a transfer of HS traffic from f1→f2 could be triggered using the features „HSDPA mobility phase 2“ and „Inter-Frequency Handover“. (HS→R99 downswitch on f1, inter-frequency handover, R99→HS upswitch on f2).The service-dependent parameterization of inter-frequency mobility (introduced in P6) could additionally support the control of a quality based move of HS traffic.


Possibilities for traffic distributionPossibilities for traffic distribution (2/2)(2/2)Second carrier strategy (3)Second carrier strategy (3)

2) Distribution of UEs in Idle ModeAnother possibility is to have no predefined access frequency, i.e. the UEs in Idle Mode are distributed on both frequencies. However, this will involve that R99 services are set up on both frequencies which represents finally strategy (4). A balanced distribution of the UEs in Idle Mode to the two frequencies can be favoured by means of equal cell selection / re-selection parameters, however, it can not be controlled to the full extent.


Conclusion: Second carrier strategy (3)Conclusion: Second carrier strategy (3)

HS HS

R99/HS R99/HS

Conclusion:As mentioned, for the 2nd carrier strategy (3), there is currently no specific parameterization possible for a reasonable and optimized distribution of HS traffic. For this purpose, the following options should be considered:

Optimize 2nd carrier strategy (1) in the best possible way, e.g.improvement of mobility at 2nd carrier coverage border.Check whether a feature/parameterization to control HS traffic distribution on two carriers is on the UTRAN product roadmap. When needed – due to growing traffic demand – move to second carrier strategy (4).

f1

f2 HS

R99/HS


CONTENTSCONTENTS



deployment project


Conclusion


CONCLUSIONCONCLUSIONThe 2nd carrier strategy implemented at present provides additional capacity and good performance for R99 users and stationary HS users. The main limitation of this strategy affects active HS users crossing the coverage border area of the 2nd carrier (in and out); they experience poor throughput and a session outage.The main improvement of the currently implemented strategy can be achieved with the introduction of the feature „HSDPA Mobility Phase 2“and the corresponding parameterization. Moreover, the activation and parameterization of „Inter-Frequency Handover“ will lead to a better performance, especially in areas at the coverage border area of the second carrier. These two features lead also to an improved handling of Multi-RAB users.The 2nd carrier strategy considered in the medium-term has R99 and HSDPA allocated on both carriers. The current UTRAN release has basic possibilities but no specific features to control this strategy in the desired manner, i.e. specific control of HS traffic distribution.


Documents

Investigation SecCarrier Strategies RevB