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User Guide 164/1553-HSD 101 02/1 Uen AF
Combined Cell
Contents
Combined Cell Overview
Dependencies of Combined Cell
Operation of Combined Cell
Network Impact of Combined Cell
Parameters for Combined Cell
Performance of Combined Cell
Activate Feature Combined Cell
Deactivate Feature Combined Cell
Engineering Guidelines for Combined Cell
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1 Combined Cell Overview
Three cell carriers combined into a single cell can extend the indoor and outdoor coverage of that cell.
Access Type: LTE WCDMA
Feature Identity: FAJ 121 3025 FAJ 121 3249
Value Package Name: Combined Cell Combined Cell
Value Package Identity: FAJ 801 0407 FAJ 801 0354
DU Radio Node DU Radio Node
Node Type:
Baseband Radio Node Baseband Radio Node
Licensing: Licensed feature. One license per node. Licensed feature. One license per node.
Summary
The Combined Cell feature extends the indoor and outdoor coverage of a single cell. This is achieved by combining up to three cell carriers into a combined cell. All cell carriers in
the same combined cell have the same Physical Cell Identity (PCI).
The feature brings the following benefits:
– Reducing the number of cells in the RNC without losing coverage, and thus simplifying the cell neighbor list.
– Enlarging coverage without introducing any extra load in the RNC.
– Reducing coverage holes by allowing multiple coverage areas within the same cell.
– Improving HSDPA throughput at the cell edge between two cell carriers in the combined cell.
– Eliminating the need for inter-cell HO within a combined cell and reducing the HO frequency.
– Coordinating the carriers in the cell to alleviate the problems caused by the Uplink (UL)/Downlink (DL) imbalance in soft or softer HO in Heterogeneous Network.
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2 Dependencies of Combined Cell
Combined Cell feature is related to Combined Cell for Small Cell Deployments (FAJ 121 4792).
Features
Table 1 Feature Dependencies
Feature Relationship Description
Combined Cell is a prerequisite for activating Combined Cell for Small Cell
Combined Cell for Small Cell Deployments (FAJ 121 4792) Related
Deployments. For more information, refer to Combined Cell for Small Cell Deployments.
4-Way Receiver Diversity (FAJ 121 1351)
EUL TD Scheduling (FAJ 121 1503) These features cannot be used in conjunction with the Combined Cell feature.
Enhanced Uplink for FACH (FAJ 121 1652) For detailed information about the 4-Way Receiver Diversity feature, refer to Optional
Features.
Psi-Coverage (FAJ 121 1679) For detailed information about the EUL TD Scheduling feature and the Enhanced
Optimized Antenna Selection (FAJ 121 4764) Uplink for FACH feature, refer to WCDMA Uplink.
Uplink Coordinated Multi-Point Reception (FAJ 121 4187)
When the Combined Cell feature is activated, this feature must be deactivated. For
HSDPA Mixed Mode Dynamic Power Sharing (FAJ 121 4609) detailed information about the HSDPA Mixed Mode Dynamic Power Sharing feature,
refer to HSDPA Mixed Mode Dynamic Power Sharing.
If the baseband pool has at least one combined cell, the Improved HSDPA Link
Adaptation feature cannot impact the calculation of maxNumHsdpaUser. For detailed
Improved HSDPA Link Adaptation (FAJ 121 1358)
information about the Improved HSDPA Link Adaptation feature, refer to Basic
Features.
When the Combined Cell feature is enabled, positioning is not accurate. It is because
RTT Positioning (FAJ 121 436) the radio node cannot detect the exact cell to which the minimum delay value belongs
Conflicting in the RTT measurement ordered by the RNC and thus cannot signal it to the RNC.
When the Combined Cell feature is activated, this feature must be deactivated. For
Dual-Band HSDPA Multi-Carrier 3 Carriers (FAJ 121 3920)
detailed information refer to Dual-Band HSDPA Multi-Carrier 3 Carriers.
When the Combined Cell feature is activated, this feature must be deactivated. For
HSDPA Multi-Carrier 3 Carriers (FAJ 121 3909)
detailed information refer to HSDPA Multi-Carrier 3 Carriers.
When the Combined Cell feature is activated, this feature must be deactivated. For
HSDPA MC Inter DU Joint Scheduling (FAJ 121 2709)
detailed information refer to HSDPA MC Inter DU Joint Scheduling.
When a combined cell is configured in radio nodes, maximum supported cell range is
Extended Range up to 80 km (FAJ 121 1030) 35 km. With this configuration, the Extended Range up to 80 km feature is not
supported. For detailed information refer to Extended Range.
When a combined cell is configured in radio nodes, maximum supported cell range is
Extended Range up to 200 km (FAJ 121 1036) 35 km. With this configuration, the Extended Range up to 200 km feature is not
supported. For detailed information refer to Extended Range.
When the Combined Cell feature is activated, this feature must be deactivated. For
Increased Cell Carrier Support (FAJ 121 3928)
detailed information refer to Increased Cell Carrier Support.
When the Combined Cell feature is activated, this feature must be deactivated. For
4TX Support for One WCDMA Carrier (FAJ 121 5381)
detailed information, refer to 4TX Support for One WCDMA Carrier.
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System Functions
Table 2 System Function Dependencies
Function Description
Licenses and Hardware Activation Codes in Ericsson Software Model To activate the Combined Cell feature, the license for the feature must be installed and enabled.
Hardware
The Combined Cell feature is supported on the DU Radio Node and Baseband Radio Node (RBS 6000 family).
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3 Operation of Combined Cell
The Combined Cell feature supports LTE and WCDMA mixed mode configurations.
Feature Overview
A non-combined cell contains only one cell carrier. A combined cell contains two or three cell carriers and it is regarded as one UTRAN cell in the RNC. One combined cell or one
non-combined cell has one downlink channelization code tree which is shared by all users in the cell.
Figure 1 shows three non-combined cells and one combined cell with three cell carriers.
Three Non-Combined Cells Combined Cell
U0001111B
Figure 1 Overview of the Combined Cell Feature Concept
In the combined cell, cell carriers must cover the overlapping geographical areas.
For DU Radio Nodes, if a cell carrier in a combined cell is lost, the service degrades and the alarm CombinedCellServiceDegraded is raised. For more information, see
CombinedCellServiceDegraded.
Supported Configurations
This feature supports W+G/W+L mixed mode configuration.
Preconditions to configure combined cells are as follows:
– Each cell carrier is configured with 2RX/1TX or 2RX/2TX.
– All cell carriers are in the same baseband pool (for DU Radio Node) or baseband unit (for Baseband Radio Node).
– No more than two frequencies on one node
– No more than three cell carriers on one frequency
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Based on the above preconditions, the feature supports the following cell configurations:
– Single combined cell configuration: one combined cell with up to three cell carriers
– Mixed configuration: one non-combined cell and one combined cell with two cell carriers
Note: Mixed configuration is only supported on Baseband Radio Node.
The supported configurations for one or two frequencies are as follows:
– One frequency
• Single combined cell configuration
• Mixed configuration
– Two frequencies
• f1: single combined cell configuration
f2: single combined cell configuration
• f1: mixed configuration
f2: mixed configuration
To support this configuration, the combined cells on two frequencies must occupy the same geographical sectors.
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Combined Cell 1 Non-Combined Cell 2
f1
Combined Cell 3 Non-Combined Cell 4
f2 S1 S3
S2
U0001484A
For the configurations not supported on two frequencies, the alarm Inconsistent Configuration is raised. For more information, see Inconsistent Configuration.
Configuration Examples
Figure 2 shows a scenario with a small number of users in the building. One code tree is enough to serve those users. Therefore, only one combined cell is configured.
IRU RD RD
Cell Carrier 3
IRU RD RD Cell Carrier 2 Combined Cell
IRU RD RD Cell Carrier 1
Baseband
Radio Node
U0001485A
Figure 2 Example of One Combined Cell Configuration
Figure 3 shows a scenario with a large number of users indoor and a small number of users outdoor. One code tree is not enough to serve the indoor and outdoor users. Therefore,
one combined cell and one non-combined cell are configured. One code tree of the non-combined cell can serve the large number of users in the building. The other code tree of
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the combined cell is enough to serve the small number of users outside.
RU
Combined Cell
RU
RU
Baseband
Radio Node
Non-Combined Cell
U0001486A
Figure 3 Example of Combined and Non-Combined Cell Configuration on Baseband Radio Node
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4 Network Impact of Combined Cell
Combined Cell enlarges coverage and improves HSDPA throughput at the cell edge between two cell carriers.
Capacity and Performance
The feature brings the following impacts on capacity and performance:
– The coverage is enlarged.
– HSDPA throughput is improved at the cell edge between two cell carriers in the combined cell.
However, compared to the cells not combined, one combined cell serves a smaller number of users due to the following:
– The number of UTRAN cells is decreased.
– The consumption of CEs and RLs for each user are increased.
For more information, see Engineering Guidelines for Combined Cell.
Interfaces
No impact is expected from this feature.
Other Network Elements
No impact is expected from this feature.
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5 Parameters for Combined Cell
Parameters from MO class Carrier::dlPowerOffsetCombinedCell and NodeBSectorCarrier are used to configure Combined Cell feature on DU Radio Node.
Parameter NodeBSectorCarrier::dlPowerOffsetCombinedCell is used to configure the feature on Baseband Radio Node.
Feature Configuration Parameters
For DU Radio Node:
– Carrier::dlPowerOffsetCombinedCell
– NodeBFunction::featureStateCombinedCell
– NodeBFunction::licenseStateCombinedCell
For Baseband Radio Node:
– NodeBSectorCarrier::dlPowerOffsetCombinedCell
Affected Parameters
Table 3 Affected Parameters in DU Radio Node
Parameter Description
Defines the maximum range (in meters) for random access detection (random access distance) covered by
Carrier::cellRange
the carrier.
Number of RX (receiver) branches.
Carrier::numberOfRxBranches
Set the same value for all cell carriers in a combined cell.
Number of RX (receiver) branches.
Carrier::numberOfTxBranches
Set the same value for all cell carriers in a combined cell.
Carrier::maxDlPowerCapability Specifies the maximum downlink power capability for the carrier.
Table 4 Affected Parameters in Baseband Radio Node
Parameter Description
NodeBSectorCarrier::cellRange Maximum range for random access detection.(1)
Maximum absolute output power of sector carrier.(1)
NodeBSectorCarrier::configuredMaxTxPower
Total cell power must be equally distributed over all sector carriers.
Number of UL antennas.(2)
NodeBSectorCarrier::numOfRxAntennas
Set the same value for all cell carriers in a combined cell.
Number of DL antennas.(2)
NodeBSectorCarrier::numOfTxAntennas
Set the same value for all cell carriers in a combined cell.
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(1) Configured in each cell carrier.
(2) Feature Combined Cell requires the same attribute value for all NodeBSectorCarriers in given NodeBLocalCell.
Related concepts
Engineering Guidelines for Combined Cell
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6 Performance of Combined Cell
This feature has no associated KPIs, counters and events.
KPIs
This feature has no associated Key Performance Indicators (KPIs).
Counters
This feature has no directly associated counters.
Events
This feature has no associated events.
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7 Activate Feature Combined Cell
CXC 402 0076 license key is necessary to activate Combined Cell feature
Prerequisites
License key CXC 402 0076
Steps
1. Order and install the license key CXC 402 0076 for the feature as specified in Licenses and Hardware Activation Codes in Ericsson Software Model.
2. Set the relevant attributes depending on the node type:
Node Type MO Instance or Parameter Name Value
DU Radio Node NodeBFunction::featureStateCombinedCell ACTIVATED
Baseband Radio Node FeatureState=CXC4020076 ACTIVATED
After This Task
No additional steps are required.
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8 Deactivate Feature Combined Cell
Prerequisites
This feature has no prerequisites for deactivating.
Steps
1. Set the relevant attributes depending on the node type:
Node Type MO Instance or Parameter Name Value
DU Radio Node NodeBFunction::featureStateCombinedCell DEACTIVATED
Baseband Radio Node FeatureState=CXC4020076 DEACTIVATED
After This Task
No additional steps are required.
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9 Engineering Guidelines for Combined Cell
Configuration guidelines for DU Radio Node and Baseband Radio Node.
DU Radio Node
– It is only allowed to configure a combined cell by importing an XML file on RBS Element Manager (EM).
• All cell carriers that are present in the same cell are considered as one logical cell, that is, the attribute cellIdentity must be the same for these cell carriers. The number
of cells with the same cellIdentity is no more than three.
• CellNumber must be the same for all the cell carriers in a combined cell, which lock these cell carriers to the same frequency.
• BBpoolId must be the same for all the cell carriers in a combined cell, which put these cell carriers to the same baseband pool.
• numberOfRxBranches and numOfTxAntennas must be the same for all the cell carriers in a combined cell.
• In one baseband pool, it is not allowed to configure a combined cell with other non-combined cells or combined cells on the same frequency.
• Up to two combined cells on different carrier frequencies for each baseband pool. The two combined cells connected to the same baseband unit are not on the same
carrier frequency.
• The two combined cells, each on different carrier frequency, can be configured with different number of cell carriers (2 or 3).
• Sectors for one combined cell must be configured with the same frequency band.
• In the steered HS allocation mode, all cell carriers of one combined cell use the same HS code resource ID.
• Flexible carrier mapping is a must for a combined cell, that is, CarrierAllocationMode must be set to Flexible.
– To have some spare E-DCH RLs to add internally at internal softer HO, the admission parameters, UtranCell::eulServingCellUsersAdm and
RbsLocalcell::maxNumEulUsers have to be set to lower values depending on the configuration, to control maximum number of EUL users.
– Combined cell can be modified with limitation by Modify RBS Equipment Configuration wizard on RBS EM.
• It is not allowed to mix existing cells to a combined cell by changing the cellIdentity to the same value.
• Local cells can be combined into an existing combined cell by adding carriers or sectors to the combined cell.
• It is not allowed to combine a local cell whose sector number is less than the sector number of the first cell carrier in the combined cell. For example, if S2C1 and S3C1
are combined, S1C1 is not allowed to be added to this combine cell.
• If a cell carrier or sector is to be removed from a combined cell, the node needs to delete all affected sectors and recreate them.
– When combining multiple non-combined cells into one combined cell, the relevant admission control parameters of the combined cell must be adjusted according to the
sum of the actual load of these non-combined cells. If the admission parameter that is license controlled is increased, an extra license needs to be ordered in advance for
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the affected radio nodes, for example, the admission parameters UtranCell::eulServingCellUsersAdm, UtranCell::eulServingCellUsersAdmTti2, and
RbsLocalCell::maxNumEulUsers.
– The following capacity changes in a combined cell compared to non-combined cells:
• The available downlink capacity is reduced.
The amount of RLs forming one RLS equals the number of cell carriers constituting one combined cell.
For example, in the case of a combined cell with three cells carriers. In DUW 10 01, for instance, each Dedicated Channel (DCH) Transmitter Module (TXM) supports 222
RLs. The number of RLS for each TXM is 74 (that is 222 divided by 3). In DUW 11, DUW 31, and DUW 41, the number of RLs supported for each DCH TXM is 294. The
number of RLS for each TXM is 98 in a combined cell configuration with three cell carriers (that is 294 divided by 3).
Below table shows the cases of a combined cell with three cell carriers.
DUW Type RL supported by each DCH TXM RLS for each TXM
DUW 10 01 222 74
DUW 11
DUW 31 294 98
DUW 41
• The maximum number of static UL CEs is reduced by 25% since the receiver complexity is increased.
• The CE consumption of HSDPA users is increased since an A-DCH or F-DPCH user has a basic cost of 1 DL CE instead of 0.5 DL CE.
For an example of site equipment configuration file, refer to Example Files for Site Equipment Configuration.
Baseband Radio Node
– All cell carriers in a combined cell must be created within the same NodeBLocalCell MO.
– NodeBLocalCell::nodeBLocalCellId must be the same for cell carriers in a combined cell.
– NodeBSectorCarrier::nodeBSectorCarrierId must not be more than three in a combined cell.
– NodeBSectorCarrier::numOfRxAntennas must be the same for all cell carriers in a combined cell.
– NodeBSectorCarrier::numOfTxAntennas must be the same for all cell carriers in a combined cell.
– The feature allows the configuration of a combined cell with non-combined cells on the same frequency.
– It is not allowed to configure a combined cell with other combined cells on the same frequency.
– Up to two combined cells can be configured on different carrier frequencies. The two combined cells, each on different carrier frequency, can be configured with different
number of cell carriers (2 or 3). In that case, the geographical sector division must be the same on the two frequencies.
– Only symmetrical configurations are supported on two different carrier frequencies. Symmetrical means that both combined and non-combined cells occupy same
geographical sectors respectively on both frequencies.
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– Sectors for one combined cell must be configured within the same frequency band.
– If a cell carrier is removed from or added to a combined cell, delete all cell carriers in the combined cell first and create them again, according to the network requirements.
– As long as one cell carrier in a combined cell is available, the corresponding UTRAN cell in the RNC is enabled. In this case, the service of the UTRAN cell is degraded.
– Compared to non-combined cells, the maximum number of UL CEs is reduced in a combined cell depends on the number of cell carriers:
• Maximum supported UL CEs is reduced to 33% for Combined Cell with three cell carriers.
• Maximum supported UL CEs is reduced to 50% for Combined Cell with two cell carriers. It is also valid for mixed configuration.
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