DC-HSDPA Feature Parameter
Description
Issue Draft A
Date 2014-01-20
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Contents
1 About This Chapter...1
1.1 Scope...1 1.2 Intended Audience...1 1.3 Change History...1
2 Overview...5
3 Basic Principle...6
3.1 Overview...6 3.2 DC-HSDPA Cells...73.2.1 Primary and Secondary Cells...7
3.2.2 Multi-Carrier Cell Groups...9
3.3 DC-HSDPA+MIMO Cells...9 3.4 Channel Mapping...10 3.4.1 Overview...10 3.4.2 HS-SCCH...11 3.4.3 HS-DPCCH...11 3.5 UE Categories...12 3.6 NodeB MAC-ehs...15 3.7 Impact on Interfaces...17 3.7.1 Overview...17 3.7.2 Impact on Iub...17 3.7.3 Impact on Uu...18
4 Technical Description...19
4.1 Overview...19 4.2 Radio Bearers...19 4.3 State Transition...21 4.4 Mobility Management...21 4.4.1 Overview...21 4.4.2 Measurement Control...21 4.4.3 Intra-Frequency Handover...22 4.4.4 Inter-Frequency Handover...224.4.6 Handover from a Non-DC-HSDPA Cell to a DC-HSDPA Cell...23
4.4.7 Inter-RAT Handover...24
4.4.8 Handover Between RNCs...24
4.5 Load Control...24
4.5.1 RAB DRD...24
4.5.2 Call Admission Control...28
4.5.3 Queuing and Preemption...29
4.5.4 Load Reshuffling and Overload Control...29
4.6 Scheduling...30
5 Related Features ...32
5.1 WRFD-010696 DC-HSDPA...32 5.2 WRFD-010699 DC-HSDPA+MIMO...336 Network Impact ...35
6.1 WRFD-010696 DC-HSDPA...35 6.2 WRFD-010699 DC-HSDPA+MIMO...367 Engineering Guidelines...37
7.1 WRFD-010696 DC-HSDPA ...377.1.1 When to Use DC-HSDPA...37
7.1.2 Required Information...37 7.1.3 Planning...38 7.1.4 Deployment...39 7.1.4.1 Requirements...39 7.1.4.2 Data Preparation...40 7.1.4.3 Precautions...41 7.1.4.4 Activation...41 7.1.4.4.1 Using MML Commands...42 7.1.4.4.2 MML Command Examples...43
7.1.4.4.3 Using the CME...44
7.1.4.5 Activation Observation...46
7.1.4.6 Deactivation...48
7.1.4.6.1 Using MML Commands...48
7.1.4.6.2 MML Command Examples...48
7.1.4.6.3 Using the CME...48
7.1.5 Performance Monitoring...49 7.1.5.1 Monitoring Counters...49 7.1.5.2 Monitoring KPIs...50 7.1.6 Parameter Optimization...51 7.1.7 Troubleshooting...51 7.2 WRFD-010699 DC-HSDPA+MIMO ...51
7.2.2 Required Information...52 7.2.3 Planning ...53 7.2.3.1 RF Planning...53 7.2.3.2 Network Planning...53 7.2.4 Deployment ...53 7.2.4.1 Requirements...53 7.2.4.2 Data Preparation...54 7.2.4.3 Precautions...54 7.2.4.4 Activation ...54 7.2.4.4.1 Using MML Commands...54 7.2.4.4.2 MML Command Examples...55 7.2.4.5 Activation Observation...56 7.2.4.6 Deactivation ...56 7.2.4.6.1 Using MML Commands...57 7.2.4.6.2 MML Command Examples...57 7.2.5 Performance Monitoring...57 7.2.6 Parameter Optimization...58 7.2.7 Troubleshooting...58
8 Parameters...59
9 Counters...212
10 Glossary...225
11 Reference Documents...226
1
About This Chapter
1.1 Scope
This document describes DC-HSDPA, including its basic principles, related features, network impact, and engineering guidelines.
DC-HSDPA involves the following features:
l WRFD-010696 DC-HSDPA
l WRFD-010699 DC-HSDPA+MIMO
1.2 Intended Audience
This document is intended for personnel who: l Need to understand the features described herein l Work with Huawei products
1.3 Change History
This section provides information about the changes in different document versions. There are two types of changes, which are defined as follows:
l Feature change
Changes in features of a specific product version l Editorial change
Changes in wording or addition of information that was not described in the earlier version
Draft A (2014-01-20)
Compared with Issue 03 (2013-12-30) of RAN15.0, Draft A (2014-01-20) of RAN16.0 includes the following changes.
Change Type Change Description Parameter Change
Feature change l Renamed the
VS.CellReserve.Coun-ter4 counter
"VS.DCHSDPA.DataTti Num.User."
l Added the impacts of the WRFD-160103 Terminal Black List feature on DC-HSDPA. For details, see 5 Related Features .
None
Editorial change Modified the feature
activation. That is, for the 3900 series base stations, BTS3902E, and BTS3803E, you are advised to run the DEA UCELL command to deactivate the MIMO Prime cells to be added to a DC-HSDPA or DC-DC-HSDPA +MIMO cell group before activating DC-HSDPA or DC-HSDPA+MIMO.
None
03 (2013-12-30)
Compared with Issue 02 (2013-06-30) of RAN15.0, Issue 03 (2013-12-30) of RAN15.0 includes the following changes.
Change Type Change Description Parameter Change
Feature change None None
Editorial change Added the WRFD-010699
DC-HSDPA+MIMO feature. For details, see 3.3 DC-HSDPA+MIMO Cells, 5 Related Features , 6 Network Impact , and 7 Engineering Guidelines.
None
02 (2013-06-30)
Change
Type Change Description ParameterChange
Feature change
None None
Editorial change
Optimized section 7.1.5.1 Monitoring Counters. None
01 (2013-04-28)
This issue includes the following changes.
Change Type Change Description Parameter
Change
Feature change None None
Editorial change Added the restrictions for DC-HSDPA load-based inter-frequency handover. For details, see 4.5.4 Load Reshuffling and Overload Control
None
Draft A (2013-01-30)
Compared with Issue 02 (2012-07-20) of RAN14.0, Draft A (2013-01-30) of RAN15.0 includes the following changes.
Change Type Change Description Parameter Change
Feature change Added the use of non-adjacent frequencies at the same frequency band for DC-HSDPA. For details, see the following sections: l 3.1 Overview
l 3.5 UE Categories
None
Changed the commands used for configuring DC-HSDPA groups from ADD DLDUALCELLGRP to ADD NODEBMULTI-CELLGRP and ADD
NODEBMULTICELLGRPI-TEM. For details, see section 3.2.2 Multi-Carrier Cell Groups.
Change Type Change Description Parameter Change Editorial change Improved the description in the
following sections: l 4.2 Radio Bearers l 4.3 State Transition l 4.4 Mobility Management l 4.5 Load Control l 5 Related Features l 6 Network Impact l 7 Engineering Guidelines None
Moved the description of the Traffic-Based Activation and Deactivation of the Supplementary Carrier In Multi-carrier feature to
Traffic-Based Activation and Deactivation of the Supplementary Carrier In Multi-carrier Feature Parameter Description.
2
Overview
Similar to Long Term Evolution (LTE), High Speed Packet Access (HSPA) is also influenced by multi-carrier aggregation. Multi-carrier aggregation enables HSPA to obtain higherbandwidth, better performance, and greater user throughput. The user throughput of multi-carrier HSPA can be twice or more times that of single-carrier HSPA.
In versions earlier than 3GPP Release 8, a UE uses only a single carrier for HSDPA transmission. The use of a single carrier for HSDPA transmission is referred to as SC-HSDPA in this document. 3GPP Release 8 introduces DC-HSDPA. DC-HSDPA uses two adjacent carriers for HSDPA transmission of a UE, doubling UE downlink throughput. 3GPP Release 10 (TS 25.331) enhances DC-HSDPA by allowing two non-adjacent carriers for HSDPA transmission of a UE. Table 2-1describes the requirements of DC-HSDPA for network elements (NEs).
Table 2-1 Requirements for NEs
Item Requirement
CN None
RNC The RNC must support the Downlink Enhanced L2 feature. The RNC must provide the radio bearer scheme for DC-HSDPA.
NodeB The NodeB must support MAC-ehs. A single MAC-ehs entity supports HS-DSCH transmission in multiple cells served by the same NodeB (FDD only).
UE In 3GPP Release 8, HS-DSCH UE categories 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, and 32 are introduced to support DC-HSDPA. In 3GPP Release 9 or later, more HS-DSCH UE categories are introduced to support DC-HSDPA.
3
Basic Principle
3.1 Overview
DC-HSDPA allows a UE to set up HSDPA connections with two inter-frequency co-coverage cells. In the downlink, the UE can simultaneously receive data over HS-DSCHs in the two cells. In the uplink, the UE using the DCH or SC-HSUPA transmits data only in the primary cell. This document describes only the DC-HSDPA UEs whose uplink connections are established on the DCH or SC-HSUPA. For details about the DC-HSDPA UEs whose uplink connections are established on the DC-HSUPA, see DC-HSUPA Feature Parameter Description.
Figure 3-1 shows an example of uplink and downlink data transmission for a DC-HSDPA UE. Figure 3-1 Example of uplink and downlink data transmission for a DC-HSDPA UE
The two cells (primary cell and secondary cell) of DC-HSDPA must meet the following restrictions:
l The two cells belong to the same sector of a NodeB and are inter-frequency co-coverage cells.
l The two cells are in the same downlink resource group of a NodeB.
l The two cells operate on frequencies that belong to the same frequency band.
The frequencies can be either adjacent or non-adjacent. Two frequencies are considered adjacent if the spacing between their center frequencies is less than or equal to 5 MHz. Two frequencies are considered non-adjacent if the spacing between their center frequencies is an integer multiple of 5 MHz. Figure 3-2 shows adjacent and non-adjacent frequencies.
Figure 3-2 Adjacent and non-adjacent frequencies
l The two cells have the same time offset (specified by the Tcell parameter). l The two cells support HSDPA and the Downlink Enhanced L2 feature. l The dual cell transmission applies only to HSDPA physical channels.
DC-HSDPA improves the throughput and delay of users in the whole cell even at the cell edge. Theoretically, DC-HSDPA with 64QAM provides a downlink peak data rate of 42 Mbit/s, which is twice the peak rate provided by 64QAM.
In multioperator core network (MOCN) or RAN sharing scenarios, the two DC-HSDPA cells can belong to different operators.
3.2 DC-HSDPA Cells
3.2.1 Primary and Secondary Cells
A DC-HSDPA group consists of two cells: the primary cell and secondary cell. From the UE perspective:
l Primary cell (also called anchor cell) carries all the types of channels for a UE. Each UE has only one primary cell.
l Secondary cell (also called supplementary cell) carries only three types of downlink (DL) channels for a UE. Each UE has only one secondary cell.
The three types of DL channels are as follows:
– HS-SCCH
– HS-PDSCH
– P-CPICH
The UARFCNDownlink and UARFCNUplink parameters in the MOD UCELLSETUP command specify the downlink and uplink operating frequency of a cell, respectively. Figure 3-3 shows the physical channels available for a DC-HSDPA UE.
Figure 3-3 Cell configuration from the UE perspective
When the cells in a DC-HSDPA group are configured with the same types of common channels as shown in Figure 3-4, either cell can serve as a primary cell. In addition, both cells can provide services for SC-HSDPA and R99 users. The RNC selects a primary cell for a DC-HSDPA UE based on the cell load and radio bearer policy. For details, see section 4.5.1 RAB DRD. If a DC-HSDPA cell also has multiple-input multiple-output (MIMO) enabled, the DC-HSDPA cell can be configured with an S-CPICH.
If the primary cell is configured with all the common channels shown in Figure 3-4, and if the secondary cell is configured with the HS-PDSCH, HS-SCCH, and P-CPICH, the secondary cell cannot provide services for SC-HSDPA and R99 users. Currently, Huawei DC-HSDPA does not support such configurations.
3.2.2 Multi-Carrier Cell Groups
DC-HSDPA requires two inter-frequency co-coverage cells. These two cells are configured as a multi-carrier cell group on the NodeB side as follows:
1. Run the NodeB MML command ADD NODEBMULTICELLGRP to add a multi-carrier cell group.
2. Run the NodeB MML command ADD NODEBMULTICELLGRPITEM to add the two DC-HSDPA cells to the multi-carrier cell group.
The NodeB reports information about cells in each multi-carrier cell group to the RNC over the Iub interface. The RNC selects a primary cell and a secondary cell for a DC-HSDPA UE based on the received cell information. For details, see section 4.5.1 RAB DRD.
NOTE
When the cells in a DC-HSDPA cell group operate on adjacent frequencies, UEs must support non-adjacent frequencies in the same frequency band.
The Tcell parameter must be set to the same value for the cells in a DC-HSDPA cell group.
After an upgrade to RAN15.0, DC-HSDPA cell groups are configured and managed through the ADD/RMV/LST NODEBMULTICELLGRP commands, and existing DC-HSDPA cell groups automatically change to multi-carrier cell groups. In RAN13.0, DC-HSDPA cell groups are configured and managed through the ADD/RMV/LST DUALCELLGRP commands. In RAN14.0, DC-HSDPA cell groups are configured and managed through the ADD/RMV/LST DLDUALCELLGRP commands.
3.3 DC-HSDPA+MIMO Cells
Configuration Modes of DC-HSDPA+MIMO Cell Groups
Figure 3-5 shows the configuration modes of the two cells in a DC-HSDPA+MIMO cell group. Figure 3-5 Configuration modes of the two cells in a DC-HSDPA+MIMO cell group
Table 3-1 Configuration modes of the two cells in a DC-HSDPA cell group
Configuration Mode Cell 1 Cell 2 Peak Rate
DC+2xMIMO+2x64QAM MIMO+64QAM MIMO+64QAM 14 x 2 x 1.5 + 14 x 2
x 1.5 = 84 Mbit/s
DC+1xMIMO+2x64QAM MIMO+64QAM 64QAM 14 x 2 x 1.5 + 14 x 1
x 1.5 = 63 Mbit/s
DC+1xMIMO+1x64QAM MIMO+64QAM HSDPA 14 x 2 x 1.5 + 14 x 1
x 1 = 56 Mbit/s
MIMO 64QAM 14 x 2 x 1 + 14 x 1 x
1.5 = 49 Mbit/s
DC+2xMIMO MIMO MIMO 14 x 2 + 14 x 2 = 56
Mbit/s
DC+1xMIMO MIMO HSDPA 14 x 2 + 14 = 42
Mbit/s
3.4 Channel Mapping
3.4.1 Overview
Figure 3-6 Channel mapping of DC-HSDPA
A DC-HSDPA UE receives two HS-DSCH transport channels from two cells of the same NodeB. Each HS-DSCH is mapped to one HS-SCCH and several HS-PDSCH physical channels. All dedicated physical control channels DPCCH and DPCH/F-DPCH in the uplink and downlink are carried on the primary cell.
3.4.2 HS-SCCH
In versions earlier than 3GPP Release 8, a UE can monitor a maximum of four HS-SCCHs at the same time, according to 3GPP TS 25.214. In a DC-HSDPA cell group, the HS-SCCHs on the primary cell are independent of those on the secondary cell. A UE can monitor a maximum of six SCCHs at the same time. In each cell, the UE can monitor a maximum of three HS-SCCHs at the same time.
There are three types of HS-SCCHs: type 1 for cells enabled with neither MIMO nor HS-SCCH Less Operation, type 2 for cells enabled with HS-SCCH Less Operation, and type 3 for cells enabled with MIMO. DC-HSDPA uses only HS-SCCH type 1. DC-HSDPA with HS-SCCH Less Operation uses HS-SCCH type 2.
HS-SCCH Less Operation applies only to the primary cell. In addition, HS-SCCH Less Operation is mutually exclusive with MIMO.
For details, see section 6A.1.1 UE procedure for receiving HS-DSCH and HS-SCCH in the CELL_DCH state in 3GPP TS 25.214 V9.8.0.
3.4.3 HS-DPCCH
The DC-HSDPA UE reports the CQI and HARQ ACK/NACK information about the two cells on the HS-DPCCH in the primary cell. The HS-DPCCH uses a new frame format that enables it to carry CQI and HARQ ACK/NACK information about the two cells in a transmission time interval (TTI).
The coding and multiplexing schemes for the HS-DPCCH are enhanced to support DC-HSDPA +MIMO. The HS-DPCCH has four coding and multiplexing schemes, which are applicable to the following scenarios:
l HSDPA: The UE is not configured in MIMO mode, and the secondary cell is not configured or activated.
l MIMO: The UE is configured in MIMO mode or DC-HSDPA+MIMO mode, and the secondary cell is not configured or activated.
l DC-HSDPA: The UE is not configured in MIMO mode, and the secondary cell is activated. l DC-HSDPA+MIMO: The UE is configured in MIMO mode, and the secondary cell is
activated.
Figure 3-7 shows the coding and multiplexing scheme for the HS-DPCCH when DC-HSDPA +MIMO is enabled.
Figure 3-7 Coding and multiplexing scheme for the HS-DPCCH when DC-HSDPA+MIMO is enabled
The ACK and NACK messages are coded and multiplexed onto the same timeslot of a subframe. The Precoding Control Indication (PCI) and Channel Quality Indicator (CQI) are multiplexed onto different subframes by using Time Division Multiplexing (TDM).
If a UE is configured in MIMO mode in one cell of a DC-HSDPA cell group, the coding schemes are as follows:
l The coding scheme for HARQ-ACK is the same as that used by a UE configured in MIMO mode in both cells of a DC-HSDPA cell group.
l If the cell is configured with MIMO, the coding and multiplexing scheme for the PCI and CQI is the same as that for HS-DPCCH in MIMO scenarios.
l If the cell is not configured with MIMO, the coding and multiplexing scheme for the PCI and CQI is the same as that for HS-DPCCH in HSDPA scenarios.
For details, see section 4.7 Coding for HS-DPCCH in 3GPP TS 25.212 V10.4.0.
3.5 UE Categories
UEs must belong to HS-DSCH category 21 or higher to support DC-HSDPA and must belong to HS-DSCH category 25, 26, 27, 28, 30, or 32 to support DC-HSDPA+MIMO, as listed in Table 3-2. For details about HS-DSCH UE categories, see section 5 Possible UE radio access capability parameter settings in 3GPP TS 25.306 V10.4.0.
Table 3-2 FDD HS-DSCH physical layer categories 21 to 32 HS-DSC H Categ ory Maxim um Numbe r of HS-DSCH Codes Receive d Mini mum Inter-TTI Interv al Maxi mum Numb er of Bits of an HS-DSCH Trans port Block Receiv ed Withi n an HS-DSCH TTI Total Numb er of Soft Chann el Bits Suppo rted Modul ation Witho ut MIM O Operat ion or Dual Cell Operat ion Suppo rted Modul ation Simult aneou s with MIM O Operat ion and Witho ut Dual Cell Operat ion Suppo rted Modul ation with Dual Cell Operat ion Suppo rted Modul ation with MIM O and Dual Cell Operat ion Categ ory 21 15 1 23370 345600 - - QPSK, 16QA M -Categ ory 22 15 1 27952 345600 Categ ory 23 15 1 35280 518400 QPSK, 16QA M, 64QA M Categ ory 24 15 1 42192 518400
HS-DSC H Categ ory Maxim um Numbe r of HS-DSCH Codes Receive d Mini mum Inter-TTI Interv al Maxi mum Numb er of Bits of an HS-DSCH Trans port Block Receiv ed Withi n an HS-DSCH TTI Total Numb er of Soft Chann el Bits Suppo rted Modul ation Witho ut MIM O Operat ion or Dual Cell Operat ion Suppo rted Modul ation Simult aneou s with MIM O Operat ion and Witho ut Dual Cell Operat ion Suppo rted Modul ation with Dual Cell Operat ion Suppo rted Modul ation with MIM O and Dual Cell Operat ion Categ ory 25 15 1 23370 691200 - - - QPSK, 16QA M Categ ory 26 15 1 27952 691200 Categ ory 27 15 1 35280 103680 0 - - - QPSK, 16QA M, 64QA M Categ ory 28 15 1 42192 103680 0 Categ ory 29 15 1 42192 777600 - - QPSK, 16QA M, 64QA M -Categ ory 30 15 1 42192 155520 0 - - QPSK, 16QA M, 64QA M QPSK, 16QA M, 64QA M Categ ory 31 15 1 42192 103680 0 - - QPSK, 16QA M, 64QA M
- HS-DSC H Categ ory Maxim um Numbe r of HS-DSCH Codes Receive d Mini mum Inter-TTI Interv al Maxi mum Numb er of Bits of an HS-DSCH Trans port Block Receiv ed Withi n an HS-DSCH TTI Total Numb er of Soft Chann el Bits Suppo rted Modul ation Witho ut MIM O Operat ion or Dual Cell Operat ion Suppo rted Modul ation Simult aneou s with MIM O Operat ion and Witho ut Dual Cell Operat ion Suppo rted Modul ation with Dual Cell Operat ion Suppo rted Modul ation with MIM O and Dual Cell Operat ion Categ ory 32 15 1 42192 207360 0 - - QPSK, 16QA M, 64QA M QPSK, 16QA M, 64QA M
The scheduling algorithm of DC-HSDPA+MIMO needs to use the I, J, and K in the new CQI table to implement TFRC. Table 3-3 describes the mapping between HS-DSCH UE categories and CQIs. For details, see 6A.2.3 CQI tables in 3GPP TS 25.214.
Table 3-3 Mapping between HS-DSCH UE categories and CQIs HS-DSCH Categor y MIMO Not Configured
MIMO Configured and Single-Stream Restriction Not Configured
MIMO and Single-Stream Restriction Configured 64QA M Not Config ured 64QA M Config ured 64QA M Not Config ured
64QAM Configured 64QA
M Not Config ured 64QA M Config ured
In Case of Type B or Single Transp ort Block Type A CQI Reports In Case of Dual Transp ort Block Type A CQI Reports In Case of Type B or Single Transp ort Block Type A CQI Reports In Case of Dual Transp ort Block Type A CQI Reports
25 C N/A C H N/A C N/A
26 D N/A D I N/A D N/A
27 C F C H F J C F
28 D G D I G K D G
30 and 32
D G D I G K N/A
According to 3GPP Release 10, non-adjacent frequencies at the same frequency band can be used for HSDPA transmission of a UE. The "Non-contiguous multi-cell" IE in the "UE radio access capability extension" IE in an RRC CONNECTION SETUP COMPLETE message specifies whether a UE supports adjacent frequencies. A UE's capability to support non-adjacent frequencies is not related to its HS-DSCH category.
l When the "Aggregated cells" IE in the "Non-contiguous multi-cell" IE is nc-2c, the UE supports two non-adjacent frequencies at the same frequency band.
l The "Gap size" IE in the "Non-contiguous multi-cell" IE specifies the spacing between the two non-adjacent frequencies supported by the UE. This IE can be set to fiveMHz, tenMHz, or anyGapSize. "fiveMHz" indicates that the UE supports a maximum of 5 MHz spacing between two non-adjacent frequencies. "tenMHz" indicates that the UE supports 5 and 10 MHz spacing between two non-adjacent frequencies. "anyGapSize" indicates that the UE supports any integer multiples of 5 MHz spacing between two non-adjacent frequencies. l When a UE does not use DC-HSDPA after accessing a DC-HSDPA cell, the RNC performs
fallback on the UE if the UE belongs to a certain HS-DSCH category. For details about HS-DSCH categories that support fallback in such a circumstance, see section 8.1.6 Transmission of UE capability information in 3GPP TS 25.331 V10.10.0.
The peak rate of a DC-HSDPA UE can reach 42.192 Mbit/s (= 2 x TB_Size/TTI = 2 x 42192/2) at the MAC layer. The peak rate of a DC-HSDPA+MIMO UE can reach 84.384 Mbit/s (= 2 x 2 x TB_Size/TTI = 2 X 2 X 42192/2) at the MAC layer. These peak rates require the support from the CN.
3.6 NodeB MAC-ehs
DC-HSDPA requires the NodeB to support MAC-ehs. A single MAC-ehs entity supports HS-DSCH transmission in more than one cell served by the same NodeB (FDD only). Queues of a
DC-HSDPA UE are common for the two cells. The scheduler in the NodeB arranges the data transmission of queues on the two cells. DC-HSDPA transmissions can be regarded as independent transmissions over two HS-DSCH channels. There will be a separate HARQ entity on each HS-DSCH channel, that is, one HARQ process per TTI for single carrier transmission and two HARQ processes per TTI for dual carrier transmission.
MAC-ehs selects Transport Format and Resource Combination (TFRC) for the MAC-ehs Protocol Data Units (PDUs) of each cell independently based on the available resources of the cells and the CQI reported by the UE.
Figure 3-8 MAC-ehs architecture
In a NodeB, two MAC-ehs PDUs can be scheduled at the same time. Figure 3-9 shows an example of traffic flow to a DC-HSDPA UE.
Figure 3-9 Example of traffic flow to a DC-HSDPA UE
3.7 Impact on Interfaces
3.7.1 Overview
To support DC-HSDPA/DC-HSDPA+MIMO, new Information Elements (IEs) are added to signaling messages.
UEs and NodeBs can report their capacity of DC-HSDPA/DC-HSDPA+MIMO to the RNC through the Iub and Uu interfaces.
l The RNC instructs cells to set up or reconfigure radio links with DC-HSDPA/DC-HSDPA +MIMO through the Iub interface.
l The RNC instructs UEs to set up or reconfigure radio bearers with DC-HSDPA/DC-HSDPA+MIMO through the Uu interface.
3.7.2 Impact on Iub
When a cell receives the AUDIT REQUEST message or when a new cell is set up or a cell capability is changed, the NodeB reports the cell capability to the RNC in Audit Response message or Resource State Indication message
l When a cell supports DC-HSDPA, the NodeB sets the Multi Cell Capability Info IE to Multi Cell Capable for the cell in Audit Response and sends the message to the RNC. l If the cell is a primary serving cell, all the possible secondary serving cells in the same
sector must be listed in the Possible Secondary Cell List IE.
When the RNC instructs a cell to set up a radio link with DC-HSDPA, the information of the secondary serving cell is added to the Radio Link Setup procedure or Radio Link Addition procedure.
The Additional HS Cell Information RL Setup IE is added to the Radio Link Setup Request/ Response/Failure messages and Radio Link Addition Request/Response/Failure messages to indicate the usage of DC-HSDPA and associated parameters.
3.7.3 Impact on Uu
In the RRC CONNECTION REQUEST message, the Multi cell support IE is added to indicate the UE capability of supporting multiple cells.
In the RRC Connection Setup Complete and UE Capability Information message, the Physical Channel Capability IE is extended to indicate the UE capability of DC-HSDPA.
The Downlink secondary cell info FDD IE in the following signaling messages indicates the usage of secondary serving cell and related parameters:
l RRC CONNECTION SETUP
l ACTIVE SET UPDATE
l CELL UPDATE CONFIRM
l PHYSICAL CHANNEL RECONFIGURATION
l TRANSPORT CHANNEL RECONFIGURATION
l RADIO BEARER RECONFIGURATION
l RADIO BEARER RELEASE
4
Technical Description
4.1 Overview
This document describes only the functions that are different from those of SC-HSDPA. These functions are as follows:
l Radio Bearers l State transition l Mobility management l Load control
l Scheduling
For details about other functions, see HSDPA Feature Parameter Description.
4.2 Radio Bearers
When the downlink transport channel HS-DSCH is selected for streaming or BE services or combined service with streaming or BE, DC-HSDPA/DC-HSDPA+MIMO can be applied. When there is only a CS service, PS conversational service, IMS signaling, or SRB signaling, DC-HSDPA/DC-HSDPA+MIMO is not applied because of small traffic volume.
To enable DC-HSDPA to carry services, perform the following configurations: l On the NodeB side
Configure DC-HSDPA cells. For details about how to configure DC-HSDPA cells, see section 3.2 DC-HSDPA Cells.
l On the RNC side
– Select CFG_HSDPA_DC_SWITCH in the RNC-level parameter CfgSwitch to enable DC-HSDPA to carry services. The CfgSwitch parameter is in the SET
– Select DC_HSDPA in the cell-level parameter HspaPlusSwitch to enable DC-HSDPA in the cell. The HspaPlusSwitch parameter is set in the ADD
UCELLALGOSWITCH and MOD UCELLALGOSWITCH commands.
– Set MIMO64QAMorDcHSDPASwitch in the SET UFRC command to DC_HSDPA to select DC-HSDPA as the preferential HSPA+ technology for the cell.
When both the network and the UE support DC-HSDPA, the UE can use DC-HSDPA for data transmission, regardless of the UE's subscribed rate. That is, the UE can use DC-HSDPA for data transmission even if the UE's subscribed rate is less than 42 Mbit/s. For details, see Radio
Bearers Feature Parameter Description.
The Continuous Packet Connectivity (CPC) function can be enabled in the DC-HSDPA cells with the following limitations:
l CPC DTX is applicable to primary cell only because there will be no uplink control channel for the DC-HSDPA UE on secondary cell
l CPC HS-SCCH Less Operation is applicable to primary cell only and is not applicable to secondary cell.
l CPC DRX for a DC-HSDPA UE on two carriers is similar to that for a UE on a single cell. DC-HSDPA and 64QAM can be used at the same time. 64QAM can be enabled in one or both cells in a DC-HSDPA cell group. When both cells in a DC-HSDPA cell group have 64QAM enabled, the peak downlink rate can reach 42 Mbit/s.
When a file is being downloaded, the TCP acknowledgement is sent in the uplink. The higher the rate of download is, the larger the bandwidth is required in the uplink. If the download rate reaches up to 42 Mbit/s, the uplink rate of TCP acknowledgement is much higher than 384 kbit/s, the highest supported by the DCH. HSUPA is required to provide high bandwidth in the uplink to transmit TCP acknowledgement without delay. The downlink rate of 42 Mbit/s per user can be supported only when HSUPA is used. Only UEs complying with 3GPP Release 9 and later support DC-HSDPA+MIMO. Table 4-1 describes the implementation of DC-HSDPA+MIMO in Huawei products.
Table 4-1 Implementation of DC-HSDPA+MIMO in Huawei products
Version Implementation Supports DC-HSDPA+MIMO Number of Cells Supporting MIMO in a DC-HSDPA Group Supports Simultaneous Use of DC-HSDPA and MIMO for UEs
RAN12.0 Yes 1 No
RAN13.0 Yes 2 Yes
RAN14.0 Yes 2 Yes
When the HS-DSCH is used for data transmission, the radio bearer policy of DC-HSDPA +MIMO is as follows:
l If a cell and UEs in this cell support HSDPA+MIMO, services of these UEs use DC-HSDPA+MIMO.
l If a cell and UEs in this cell support only DC-HSDPA or MIMO, services of these UEs use only DC-HSDPA or MIMO.
l If a cell and UEs in this cell support both HSDPA and MIMO but do not support DC-HSDPA+MIMO, services of these UEs use the preferred HSPA+ technology for the cell. The preferred HSPA+ technology for a cell is specified by the
MIMO64QAMorDCHSDPASwitch parameter in the SET UFRC command.
NOTE
For details about transport channel selection, see Radio Bearers Feature Parameter Description.
4.3 State Transition
DC-HSDPA UEs only support the CELL_DCH state. After DC-HSDPA UEs transition to other states, they cannot be carried on DC-HSDPA. DC-HSDPA UEs can perform state transition only in the primary cell.
When a UE supporting DC-HSDPA transitions from the CELL_FACH, CELL_PCH, or URA_PCH state to the CELL_DCH state, the RNC establishes a DC-HSDPA radio bearer (RB) for the UE. After the state transition is complete, the RNC performs RAB DRD to select an appropriate DC-HSDPA group for the UE. For details, see section 4.5.1 RAB DRD.
NOTE
DC-HSDPA RB refers to the HSDPA RB that has DC-HSDPA enabled.
The state transition trigger threshold for DC-HSDPA UEs is the same as that for SC-HSDPA UEs. For details, see State Transition Feature Parameter Description.
DC-HSDPA+MIMO applies the same principles as DC-HSDPA in state transition.
4.4 Mobility Management
4.4.1 Overview
The introduction of DC-HSDPA has no impact on handover measurement triggering and handover decision processes. During a handover, however, the RNC needs to decide whether DC-HSDPA is used after the handover if the target cell supports DC-HSDPA, or whether non-DC-HSDPA is used after the handover if the target cell does not support non-DC-HSDPA.
This section describes only the mobility management of DC-HSDPA. For other information about handover, see Handover Feature Parameter Description.
4.4.2 Measurement Control
When DC-HSDPA is enabled, the RNC maintains the active set only in the primary cell. Intra-frequency measurement control for DC-HSDPA UEs is the same as that for SC-HSDPA UEs.
l Compressed mode
Inter-frequency measurement control for DC-HSDPA UEs in compressed mode is the same as that for SC-HSDPA UEs in compressed mode.
l Non-compressed mode
DC-HSDPA UEs perform inter-frequency measurements in non-compressed mode when all of the following conditions are met:
– CMP_UU_ADJACENT_FREQ_CM_SWITCH in the CmpSwitch parameter for the
SET UCORRMALGOSWITCH command is selected.
When CMP_UU_ADJACENT_FREQ_CM_SWITCH is selected, the UE can perform inter-frequency measurements in non-compressed mode on frequencies spaced less than or equal to 5 MHz from the operating frequency of the UE. For a DC-HSDPA network, it is recommended that this switch be turned off, because the UE currently cannot report whether it is allowed to use the non-compressed mode for frequencies of neighboring cells within 5 MHz from the current frequency.
– The value of the following IE in the RRC CONNECTION SETUP COMPLETE message sent by the UE is TRUE: "UE radio access capability" IE > "Measurement capability" IE > "Adjacent frequency measurements without compressed mode" IE. – If UEs are performing DC-HSDPA services, the UE performs inter-frequency
measurements only in the cells operating on the same frequency as the secondary cell and the frequency is spaced less than or equal to 5 MHz from the operating frequency of the current cell.
– If UEs are not performing DC-HSDPA services, the UE performs inter-frequency measurements in the cells that meet the following conditions:
-The cells operate on the same frequency at the same frequency band as the current cell. -The cells operate on frequencies whose center frequencies are spaced less than or equal to 5 MHz away from the center frequency of the current cell.
-All cells to be measured operate on the same frequency.
4.4.3 Intra-Frequency Handover
When receiving a measurement report from a DC-HSDPA UE indicating that the signal quality of a DC-HSDPA cell is better than that of the serving cell (a DC-HSDPA cell), the RNC decides whether to perform a DC-HSDPA handover to the target cell:
l If the admission to the target cell is allowed and the radio link configuration is successful, the RNC performs the handover.
l If the admission to the target cell is allowed but the radio link configuration is unsuccessful, the RNC reconfigures the service on SC-HSDPA and then performs an SC-HSDPA handover.
l If the admission to the target cell is not allowed, the RNC reconfigures the service on the DCH and performs a DCH handover:
– If the DCH handover is allowed, the RNC performs the handover. – Otherwise, the RNC does not perform the handover.
4.4.4 Inter-Frequency Handover
During an inter-frequency handover, the DC-HSDPA UE needs to measure the signal quality of the primary cell and its neighboring cells. If the secondary cell is a neighboring cell of the primary
cell, the DC-HSDPA UE also needs to measure the signal quality of the secondary cell. The inter-frequency handover process for DC-HSDPA UEs is the same as that for SC-HSDPA UEs. For details about inter-frequency handovers, see Handover Feature Parameter Description.
4.4.5 Handover from a DC-HSDPA Cell to a Non-DC-HSDPA Cell
Upon receiving a measurement report from a DC-HSDPA UE indicating that the signal quality of an inter-frequency non-DC-HSDPA cell is better than that of the serving cell (a DC-HSDPA cell), the RNC initiates an RB reconfiguration procedure to make the service be carried on the DCH or HSDPA and meanwhile performs a handover.
Upon receiving a measurement report carrying the signal quality of intra-frequency non-DC-HSDPA cells, the RNC performs different operations in different scenarios. Details are as follows:
l If an intra-frequency non-DC-HSDPA cell in the active set reports event 1D:
– The RNC initiates an RB reconfiguration procedure to make the service be carried on the DCH or HSDPA and meanwhile initiates a serving cell change procedure when CMP_UU_SERV_CELL_CHG_WITH_RB_MOD_SWITCH in the CmpSwitch parameter is selected.
– The RNC initiates an RB reconfiguration procedure to make the service be carried on the DCH or HSDPA and then initiates a serving cell change procedure when
CMP_UU_SERV_CELL_CHG_WITH_RB_MOD_SWITCH in the CmpSwitch parameter is deselected.
l If an intra-frequency non-DC-HSDPA cell outside the active set reports event 1D: – The RNC initiates an RB reconfiguration procedure to make the service be carried on
the DCH or HSDPA and then initiates an active set update procedure with serving cell change when CMP_UU_SERV_CELL_CHG_WITH_ASU_SWITCH in the
CmpSwitch parameter is selected.
– The RNC initiates an RB reconfiguration procedure to make the service be carried on the DCH or HSDPA, initiates an active set update procedure, and then initiates a serving cell change procedure when
CMP_UU_SERV_CELL_CHG_WITH_ASU_SWITCH in the CmpSwitch parameter is deselected.
The CmpSwitch parameter is set using the SET UCORRMALGOSWITCH command.
4.4.6 Handover from a Non-DC-HSDPA Cell to a DC-HSDPA Cell
Upon receiving a measurement report indicating that the signal quality of a DC-HSDPA cell is better than that of the serving cell (a non-HSDPA cell), the RNC performs a handover after which the HSPA+ technologies supported by both the source cell and the target cell are used in the target cell. If such HSPA+ technologies are ranked lower than some HSPA+ technologies supported by both the target cell and the UE, the ChannelRetryHoTimerLen timer is started after the handover. When the timer expires, the RNC tries to reconfigure the traffic radio bearer (TRB) and signaling radio bearer (SRB) to enable them to support the higher-ranked HSPA+ technologies. If the reconfiguration fails, the RNC starts the retry timer
(ChannelRetryTimerLen) for periodic retry attempts.
The HSPA+ technologies that can be retried are specified by the parameter RetryCapability in the SET UFRC command.
The ChannelRetryHoTimerLen and ChannelRetryTimerLen parameters are set using the SET UCOIFTIMER command.
4.4.7 Inter-RAT Handover
The inter-RAT handover process for DC-HSDPA UEs is the same as that for SC-HSDPA UEs. For details about inter-RAT handovers, see Handover Feature Parameter Description. After a UE is handed over to a DC-HSDPA cell from a cell belonging to another RAT, the UE is carried on HSDPA. The RNC starts a retry timer as soon as the handover is complete. When the timer expires, the RNC initiates an RB reconfiguration procedure to make the UE carried on DC-HSDPA or a higher HSPA+ technology. If the reconfiguration fails, the RNC starts the retry timer for periodic DRD.
The ChannelRetryTimerLen parameter in the SET UCOIFTIMER command specifies the retry timer.
4.4.8 Handover Between RNCs
The current version does not support the handover between different RNCs for DC-HSDPA users.
During the handover, if the target cell is from different RNC, the DC-HSDPA user falls back to SC-HSDPA and then the handover is performed.
Upon completion of the handover, if DC-HSDPA is included in HSPA technologies that can be retried by UEs (that is, DC-HSDPA under the RetryCapability parameter is turned on) and the handover target cell supports HSDPA, the RNC will attempt to switch the services on DC-HSDPA RABs.
4.5 Load Control
4.5.1 RAB DRD
During a RAB setup or a state transition from CELL_FACH to CELL_DCH, the RNC performs DRDs to select a primary cell and a secondary cell for DC-HSDPA/DC-HSDPA+MIMO UEs. This section describes the DRD for DC-HSDPA/DC-HSDPA+MIMO UEs. For more details about DRD, see Directed Retry Decision Feature Parameter Description.
DRD Procedure
1. The RNC selects cells that meet the quality requirements of inter-frequency DRD as candidate cells.
For details about the quality requirements of inter-frequency DRD, see section 4.2.1 "Inter-Frequency DRD" in Directed Retry Decision Feature Parameter Description.
2. The RNC performs the following operations to select a cell from candidate cells as the primary cell.
When DRD for device type steering is enabled, the RNC selects the candidate cell with the highest device type steering priority as the primary cell and proceeds to step 3. If multiple candidate cells all have the highest device type steering priority or if DRD for device type steering is disabled, proceed to step (b).
For details about how to select candidate cells based on device type steering, see section 4.2.2 "Inter-Frequency DRD for Device Type Steering" in Directed Retry Decision Feature
Parameter Description.
(b) When DRD for HSPA+ technological satisfaction is enabled, the RNC selects the candidate cell with the highest HSPA+ technological satisfaction as the primary cell and proceeds to step 3. If multiple candidate cells all have the highest HSPA+ technological satisfaction or if DRD for HSPA+ technological satisfaction is disabled, proceed to step (c).
For details about how to select candidate cells based on the HSPA+ technological satisfaction, see section 4.2.3 "Inter-Frequency DRD for Technological Satisfaction" in
Directed Retry Decision Feature Parameter Description.
(c) When DRD for service steering is enabled, the RNC selects the candidate cell with the highest service priority as the primary cell and proceeds to step 3. If multiple candidate cells all have the highest service priority or if DRD for service steering is disabled, proceed to step (d).
For details about how to select candidate cells based on the service priority, see section Service Priority-based Cell Selection.
(d) When DRD for UE location is enabled, the RNC selects a candidate cell as the primary cell based on DRD for UE location and proceeds to step 3. If multiple candidate cells meet the requirements of DRD for UE location, proceed to step (e).
For details about how to select candidate cells based on the frequency band priority, see section 4.2.5 "Multiband Direct Retry Based on UE Location" in Directed Retry Decision
Feature Parameter Description.
(e) When DRD for load balancing is enabled, the RNC selects the candidate cell with the lightest downlink load based on downlink load balancing. For a DC-HSDPA cell, the RNC considers the downlink load of the corresponding DC-HSDPA group, not the downlink load of the HSDPA cell. Therefore, the RNC selects at least two cells in the same DC-HSDPA group as candidate cells. Then, the RNC selects the cell with the lightest load as the primary cell based on uplink load balancing and proceeds to step 3.
For details about how to select cells based on downlink load balancing, see Downlink Load-based Cell Selection. For details about how to select cells based on uplink load balancing, see Uplink Load-based Cell Selection.
3. The RNC selects the other cell in the DC-HSDPA group to which the primary cell belongs as the secondary cell. The DRD procedure is complete. Then, the RNC performs call admission control (CAC). For details, see section 4.2.1 "Inter-Frequency DRD" in Directed
NOTE
The HSPA technological satisfaction of DC-HSDPA cells is the same as that of SC-HSDPA cells. When all of the preceding DRD functions are disabled, the RNC instructs the UE to access the cell with the highest HSPA technological satisfaction. If the access fails, the RNC randomly selects a cell from candidate cells for the UE. If the cell supports DC-HSDPA, the cell serves as the primary cell, and the other cell in the DC-HSDPA group serves as the secondary cell. If the cell does not support DC-HSDPA, the UE accesses the cell with the highest technology supported by the cell.
Service Priority-based Cell Selection
The service priority-based cell selection for DC-HSDPA UEs is the same as the target cell selection for SC-HSDPA UEs.
When multiple candidate cells support the same HSPA+ technologies, the RNC determines the service priorities of cells based on the uplink and downlink service bearers for the UE if DRD for service steering is enabled. The RNC then ranks candidate cells according to service priority and selects the cell with the highest service priority as the candidate cell.
The RNC uses HSDPA as the downlink service bearer for DC-HSDPA UEs.
If the requested service is combined services, the RNC uses the RAB with the highest priority for ranking. In addition, the selected cell must support all services in the combined services. For details about the priority of a RAB, see Load Control Feature Parameter Description.
For details about how to select cells based on the service priority, see section 4.2.4 "Inter-Frequency DRD for Service Steering" in Directed Retry Decision Feature Parameter
Description.
Downlink Load-based Cell Selection
The DRD for load balancing function for DC-HSDPA UEs is performed based on the number of power resources available in the downlink and is basically the same as the downlink load balancing-based DRD for SC-HSDPA UEs. The only difference is that the RNC considers the load of the DC-HSDPA group to which the candidate cell belongs when performing DRD based on load balancing for DC-HSDPA UEs.
For details about the downlink load balancing-based DRD, see section 4.2.6 "Inter-Frequency DRD for Load Balancing" in Directed Retry Decision Feature Parameter Description.
Uplink Load-based Cell Selection
DC-HSDPA UEs have uplink channels only in the primary cell. If a large number of DC-HSDPA UEs use a cell as the primary cell, the uplink load of the cell increases, and the uplink coverage deteriorates. The uplink load-based cell selection function helps balance the uplink load between two carriers.
l If the uplink load balancing switch ULLdbDRDSwitchDcHSDPA is set to OFF, the RNC randomly selects a cell from candidate cells as the primary cell.
l If this switch is set to ON, the RNC selects the cell with the lightest uplink load as the candidate primary cell.
The RNC performs the uplink load balancing between candidate cells based on the equivalent number of users (ENUs) in the uplink.
1. If the UE initiates an RRC connection request in a non-candidate cell, the RNC selects the cell with the lightest uplink load from candidate cells as the primary cell.
2. In other circumstances, the RNC checks whether the remaining uplink ENUs of the current cell are greater than the value of the ULLdbDRDLoadRemainThdDCHSDPA parameter. l If the remaining uplink ENUs of the current cell are greater than the value of the
ULLdbDRDLoadRemainThdDCHSDPA parameter, the RNC selects the current cell as
the primary cell.
l If the remaining uplink ENUs of the current cell are less than or equal to the value of the
ULLdbDRDLoadRemainThdDCHSDPA parameter, the RNC calculates the difference
between the remaining uplink ENUs of the candidate primary cell and that of the current cell.
– If the difference is greater than the value of ULLdbDRDOffsetDcHSDPA, the RNC selects the candidate primary cell as the primary cell.
– Otherwise, the RNC selects the current cell as the primary cell.
After selecting the primary cell, the RNC selects the other cell in the same DC-HSDPA group as the secondary cell.
4.5.2 Call Admission Control
Overview
In terms of Call Admission Control (CAC) based on the code resource, CE resource, or Iub resource, DC-HSDPA CAC is not changed, compared with SC-HSDPA CAC.
In terms of CAC based on the DL power or equivalent number of users (ENU), DC-HSDPA CAC is changed, that is, the resources of the DC-HSDPA cell group need to be considered.
CAC Based on the DL Power
Figure 4-2 shows the resource allocation in the two cells of a DC-HSDPA cell group. In this figure, the DL power is taken as an example.
The variables in Figure 4-2 are described as follows: l Pmax: maximum DL power of a cell
l Pnon-HSPA: DL power used for non-HSPA UEs in a cell
l GBPSC-H: DL power required by the HS-PDSCHs to provide GBRs for SC-HSDPA UEs in a cell.
l GBPDC-H: DL power required by the HS-PDSCHs to provide GBRs for the DC-HSDPA UEs in the DC-HSDPA cell group.
For a HSDPA UE, the RNC performs CAC based on the total DL power margin of the DC-HSDPA cell group because the UE can use the DL power margin of any of the two cells after the admission.
For a non-DC-HSDPA UE, the RNC performs CAC based on the total DL power of the serving cell minus the DL power used for the existing non-DC-HSDPA UEs in this cell. If the admission is successful, the RNC continues to perform the CAC based on the total DL power margin of the DC-HSDPA cell group.
CAC Based on the ENU
The CAC based on the Equivalent Number of Users (ENU) is similar to CAC based on the DL power.
For a DC-HSDPA UE, the RNC performs CAC based on the total ENU of the DC-HSDPA cell group.
For a non-DC-HSDPA UE, the RNC first performs CAC based on the ENU of the serving cell. If the admission is successful, the RNC then continues to perform the CAC based on the ENU of the DC-HSDPA cell group.
CAC Based on the Number of HSDPA Users
The HSDPA services have to make admission decision based on the number of HSDPA users. The DC-HSDPA costs only one HSDPA license user in the primary cell.
4.5.3 Queuing and Preemption
The UE requesting DC-HSDPA services will be queued in the selected primary cell. The queuing principle is the same as that described in the Load Control Feature Parameter Description. For DC-HSDPA services, the RNC selects the primary cell in the DC-HSDPA cell group to perform preemption.
4.5.4 Load Reshuffling and Overload Control
The power resources of a DC-HSDPA group may be in the basic congestion or overload state. Basic congestion is triggered when the sum of non-HSPA user power and HSPA user GBP of the two cells is greater than or equal to the sum of the downlink LDR trigger thresholds for the two cells. Overload is triggered when the sum of non-HSPA user power and HSPA user GBP of the two cells is greater than or equal to the sum of the downlink OLC trigger thresholds for the two cells.
NOTE
l GBP: Guaranteed Bit rate Power l LDR: load reshuffling
l OLC: overload control
If a DC-HSDPA group is in the basic congestion or overload state, both cells in the DC-HSDPA group are in the basic congestion or overload state. Under this condition, the RNC performs load reshuffling or overload control to relieve the congestion or overload. For details about load reshuffling and overload control, see sections "LDR Actions" and "OLC Actions" in Load
Control Feature Parameter Description, respectively.
The LDR and OLC for SC-HSDPA and R99 users are always the same, no matter whether they are in DC-HSDPA cells or non-DC-HSDPA cells.
When LDR is implemented through load-based inter-frequency handovers, the target cell cannot be a secondary cell of a DC-HSDPA UE if the RNC performs LDR on the DC-HSDPA UE. Other LDR actions are the same as those before the DC-HSDPA feature is applied. For details, see Load Control Feature Parameter Description.
DC-HSDPA+MIMO applies the same principles as DC-HSDPA in load control.
4.6 Scheduling
The NodeB selects the first cell from the two cells to perform the scheduling process. If the first cell cannot transmit all the data of a UE, the NodeB selects the second cell to provide services. After determining the cell, the NodeB needs to determine the queuing of this UE and other UEs in this cell.
The method of DC-HSDPA scheduling is similar to that of SC-HSDPA scheduling. For details, see HSDPA Feature Parameter Description. This section describes only the difference between the two scheduling methods.
The calculation of the scheduling priority of a DC-HSDPA queue needs to consider different CQIs and Uu rates of the two carriers. In the proportional fair (PF) algorithm and enhanced proportional fair (EPF) algorithm, R/r used for DC-HSDPA is different from that used for SC-HSDPA:
l For SC-HSDPA, R represents the throughput corresponding to the CQI reported by the UE for this carrier, and r represents the throughput currently achieved by the UE. A greater R/
r value indicates a higher scheduling priority.
l For DC-HSDPA, R represents the throughput corresponding to the CQI reported by the UE for this carrier, and r represents the total throughput currently achieved by the UE on the two carriers. A greater R/r value indicates a higher scheduling priority.
Scheduling in this way ensures the throughput fairness among DC-HSDPA users and SC-HSDPA users if they are in the same channel environments. The throughput of DC-SC-HSDPA users is slightly higher than that of SC-HSDPA users because DC-HSDPA users can be scheduled in the carrier with higher CQI of the two carriers.
If DC-HSDPA users are expected to have a higher throughput than SC-HSDPA users, you can apply the differentiated service policy. For details, see Differentiated HSPA Service Feature
DC-HSDPA+MIMO applies the same principles as DC-HSDPA in scheduling. The TFRC algorithm used by DC-HSDPA+MIMO is the same as that used by MIMO. For details, see
5
Related Features
5.1 WRFD-010696 DC-HSDPA
Prerequisite Features
l WRFD-010610 HSDPA Introduction Package
l WRFD-010629 DL 16QAM Modulation
l WRFD-010685 Downlink Enhanced L2
DC-HSDPA must be enabled together with the WRFD-010683 Downlink 64QAM feature to provide the single-user downlink peak throughput of 42 Mbit/s.
Mutually Exclusive Features
DC-HSDPA is mutually exclusive with the WRFD-021308 Extended Cell Coverage up to 200km feature.
Impacted Features
DC-HSDPA is affected by the following features: l WRFD-010617 VoIP over HSPA/HSPA+
– DC-HSDPA cannot be used for voice over IP (VoIP) services.
– DC-HSDPA can be used for combined VoIP+PS BE or VoIP+streaming services. l WRFD-010619 CS voice over HSPA/HSPA+
– DC-HSDPA cannot be used for CS services.
– DC-HSDPA can be used for combined CS+PS BE or CS+streaming services l WRFD-020134 Push to Talk
– DC-HSDPA cannot be used for push to talk (PTT) services.
l WRFD-160103 Terminal Black List
When the WRFD-160103 Terminal Black List feature is enabled, blacklisted users are prohibited from using DC-HSDPA.
DC-HSDPA affects the following features:
l WRFD-140217 Inter-Frequency Load Balancing Based on Configurable Load Threshold When the number of DC-HSDPA UEs and their traffic volume are small, DC-HSDPA does not affect the Inter-Frequency Load Balancing Based on Configurable Load Threshold feature.
When the number of DC-HSDPA UEs and their traffic volume are large, the gain provided by the Inter-Frequency Load Balancing Based on Configurable Load Threshold feature decreases. The reason is as follows: DC-HSDPA uses joint scheduling to balance the load across different carriers. The load balancing effect depends on the number of DC-HSDPA UEs and the traffic volume. When the number of DC-HSDPA UEs and the traffic volume are large, the load balancing effect is noticeable, but the gain provided by the Inter-Frequency Load Balancing Based on Configurable Load Threshold feature decreases. l WRFD-140215 Dynamic Configuration of HSDPA CQI Feedback Period
DC-HSDPA can be used with the Dynamic Configuration of HSDPA CQI Feedback Period feature.
When these two features are used together, the gain (RTWP reduction) provided by the Dynamic Configuration of HSDPA CQI Feedback Period feature slightly increases, compared with when SC-HSDPA and Dynamic Configuration of HSDPA CQI Feedback Period are used together. The uplink CQI feedback overhead for DC-HSDPA is slightly greater than that for SC-HSDPA, so the received total wideband power (RTWP) of DC-HSDPA is higher than that of SC-DC-HSDPA. The Dynamic Configuration of DC-HSDPA CQI Feedback Period feature helps reduce the RTWP.
l WRFD-021304 RAN Sharing Introduction Package, WRFD-021305 RAN Sharing Phase 2, and WRFD-021311 MOCN Introduction Package
In RAN sharing and MOCN scenarios, the RNC determines whether to use cells belonging to different operators for HSDPA transmission of a DC-HSDPA UE based on the parameter settings.
l WRFD-010689 HSPA+ Downlink 42Mbps per User
After DC-HSDPA is introduced, the HSPA+ Downlink 42Mbps per User feature can depend on the following feature: WRFD-010696 DC-HSDPA.
5.2 WRFD-010699 DC-HSDPA+MIMO
Prerequisite Features
l WRFD-010696 DC-HSDPA
l WRFD-010684 2x2 MIMO
For details on how to activate the WRFD-010684 2x2 MIMO feature, see chapter 12 "Engineering Guidelines" in MIMO Feature Parameter Description.
Mutually Exclusive Features
NoneImpacted Features
The WRFD-010703 HSPA+ Downlink 84Mbit/s per User feature depends on DC-HSDPA +MIMO. In addition, to achieve the single-user downlink peak throughput of 84 Mbit/s, DC-HSDPA+MIMO must be used together with the WRFD-010683 Downlink 64 QAM feature.
6
Network Impact
6.1 WRFD-010696 DC-HSDPA
System Capacity
DC-HSDPA provides the following benefits:
l Increases single-user downlink peak throughput. DC-HSDPA together with 64QAM pushes the single-user downlink peak throughput up to 42 Mbit/s.
l Reduces the transmission delay of burst services and improves user experience.
DC-HSDPA UEs have the HS-DPCCH only in the primary cell, and therefore the uplink load of the primary cell is slightly higher than that of SC-HSDPA cells.
DC-HSDPA UEs consume one channel element (CE) more than SC-HSDPA UEs.
Network Performance
DC-HSDPA affects cell uplink load and cell downlink load. l Impact on cell uplink load
Compared with SC-HSDPA UEs, DC-HSDPA UEs need to demodulate the signals in the primary and secondary cells and need to report the feedback about both cells in the primary cell. The transmit power of a DC-HSDPA UE on the HS-DPCCH is about 2 dB higher than that of an SC-HSDPA UE. Theoretically, the uplink load of a DC-HSDPA UE in the primary cell is about 0.2% higher than that of an SC-HSDPA UE. When the penetration rate of DC-HSDPA UEs is small, this feature has little impact on network performance. l Impact on cell downlink load
– For cells that have the same HSDPA service priority, DC-HSDPA does not significantly affect the downlink load.
– For cells that have different HSDPA service priorities, DC-HSDPA increases the downlink load of the cell with lower HSDPA service priority. The load increase is related to the proportion of UEs supporting DC-HSDPA and service model.
6.2 WRFD-010699 DC-HSDPA+MIMO
System Capacity
DC-HSDPA+MIMO provides the following benefits:
l Increases user downlink peak throughput. DC-HSDPA+MIMO increases the single-user downlink throughput by about 100% compared with SC-HSDPA+MIMO. The increase in the single-user downlink throughput is noticeable even at the cell edge. However, the increase in the single-user downlink throughput varies depending on the load of other HSDPA+MIMO cells in the same sector. For example, when other HSDPA+MIMO cells in the same sector have heavy loads, the gain provided by DC-HSDPA+MIMO is small.
l Reduces the transmission delay of burst services and improves user experience. DC-HSDPA+MIMO UEs consume one CE more than SC-HSDPA+MIMO UEs. A baseband processing board supports more SC-HSDPA+MIMO UEs than DC-HSDPA +MIMO UEs.
Network Performance
l Slightly increases the cell load in the uplink. The cell load increase is represented by an increase in the uplink RTWP. The increase in the uplink RTWP varies depending on the number of online DC-HSDPA+MIMO UEs. When the number of online DC-HSDPA +MIMO UEs increases, the HS-DPCCH has more data to transmit in the uplink and consequently requires more power resources. Uplink interference increases as a result. l Deteriorates uplink cell edge coverage. DC-HSDPA+MIMO slightly deteriorates the
uplink cell edge coverage because DC-HSDPA+MIMO UEs need to report the CQI information about both serving cells and consequently require higher uplink power. l For details about the impacts on downlink cell load, see Network Performance.
7
Engineering Guidelines
7.1 WRFD-010696 DC-HSDPA
7.1.1 When to Use DC-HSDPA
DC-HSDPA applies to operators who have at least two frequencies at the same frequency band. It is recommended that DC-HSDPA be deployed in urban areas. In the busy time, user-selective scheduling and load balancing of DC-HSDPA increases capacity. In the spare time, DC-HSDPA increases maximum user throughput and reduces delay.
DC-HSDPA can be deployed in suburban areas or rural areas. It improves user overall experience and significantly improves the edge users' experience.
In urban areas where the network capacity is not limited, DC-HSDPA provides more benefits if most services on the live network are burst services. Details are as follows:
Compared with SC-HSDPA, DC-HSDPA doubles the single-user throughput in the cell center and at the cell edge. DC-HSDPA also reduces the transmission delay and improves user experience. However, when the number of UEs performing data transmission increases, the downlink load increases, and as a result the feature benefits in single-user throughput and cell throughput decrease.
DC-HSDPA can also be deployed in networks with limited capacity and high downlink load (for example, the average downlink transmit power is greater than 80% for a long time), but the feature benefits are less noticeable.
7.1.2 Required Information
Before feature deployment, operators need to collect the following information: l Proportion of UEs supporting DC-HSDPA
A higher proportion of UEs supporting DC-HSDPA results in better system throughput gains. The VS.HSDPA.UE.Mean.CAT21.24 and VS.HSDPA.UE.Mean.CAT25.28 counters measure the average numbers of DC-HSDPA UEs.
l Uplink capabilities
If dedicated channels (DCHs) are used in the uplink, the downlink peak rates for DC-HSDPA users are restricted, resulting in decreased gains. HSUPA is recommended in the uplink for DC-HSDPA.
For details about how to check whether HSUPA is enabled in the uplink, see HSUPA Feature
Parameter Description.
l Bandwidth over the Iub interface
If the bandwidth over the Iub interface is inadequate, DC-HSDPA cannot yield no gains. An appropriate bandwidth is required over the Iub interface.
DC-HSDPA provides single-user downlink peak throughput of 42 Mbit/s. The minimum bandwidth over the Iub interface is 50 M in IP transmission and is 55 M in ATM transmission considering the Iub transmission efficiency. The actual bandwidth required over the Iub interface is greater than 50 M because there are R99 users on the live network. The actual bandwidth required over the Iub interface must be calculated based on network planning and network optimization.
l Packet loss rate on the core network
If the core network has a high packet loss rate, gains provided by DC-HSDPA decrease during single-thread FTP sessions. An appropriate packet loss rate is required for the core network. The recommended packet loss rate over the Iu interface is less than one of a million. l Downlink cell load
If the downlink loads of cells in the same sector exceed 85% for most of the time, the benefits provided by DC-HSDPA may decrease.
The VS.MeanTCP counter measures the downlink load of a cell.
7.1.3 Planning
DC-HSDPA sets the following requirements on NodeB hardware:
l For 3900 series base stations, the BBU3900 needs to be configured with the WBBPb, WBBPd, UBBP, or WBBPf board.
l For the DBS3800, the BBU3806 needs to be configured with the EBBC or EBBCd board. l The BTS3812AE or BTS3812E needs to be configured with the EBBI, EDLP, or EDLPd board, and the UL baseband resources of DC-HSDPA cells cannot be carried on the HBBI or HULP board. They need to be carried on the EBBI, EULP, or EULPd board.
Table 7-1 presents an example of the hardware configuration of a NodeB that is configured with three sectors, with two carriers in each sector.
Table 7-1 Example of the hardware configuration of a NodeB that is configured with three sectors (with two carriers in each sector)
Base Station Type Hardware Configuration
3900 series base stations
Each 3900 series base station must be configured with one WBBPb, one WBBPd, one UBBP, or one WBBPf board.
Base Station Type Hardware Configuration
DBS3800 The DBS3800 must be configured with one EBBC or one EBBCd
board. BTS3812AE and
BTS3812E
Each NodeB of these types must be configured either with one EDLP board and one EULP or EULPd board or with one EBBI board.
7.1.4 Deployment
This section describes how to activate, verify, and deactivate the optional feature WRFD-010696 DC-HSDPA.
7.1.4.1 Requirements
l Other Features
The cells to be enabled with DC-HSDPA must have the prerequisite features enabled. For details about the prerequisites features for DC-HSDPA, see section Prerequisite
Features.
l License
The license "The number of Cells with DL DC function enabled" on the NodeB side has been activated. For details about how to activate the license, see License Management
Feature Parameter Description.
Feature ID Feature Name License Control Item NE Sales Unit WRFD-01069 6
DC-HSDPA The number of
Cells with DL DC function enabled
NodeB per Cell
l Others
– One local cell can belong to only one DC-HSDPA group.
– The two DC-HSDPA cells must belong to the same baseband board. – The two DC-HSDPA cells must belong to the same sector.
– The two DC-HSDPA cells of a DC-HSDPA group are in the same downlink resource group of a NodeB.
After the configuration of DC-HSDPA cell group, the NodeB tries to set up all the cells in the DC-HSDPA cell group in the same board. If not all the cells are set up in the same group, the NodeB reports ALM-28206 Local Cell Capability Decline.
– For distributed cells, two local cells in a DC-HSDPA cell group must belong to one RRU. For non-distributed cells, if two local cells in a DC-HSDPA cell group belong to two RRUs, the RRUs adopt a star or chain topology.
