35 tx rx diversity
DESCRIPTION
TX RXTRANSCRIPT
RAN Feature Description Table of Contents
Table of Contents
Chapter 35 TX/RX Diversity......................................................................................................35-135.1 Introduction..................................................................................................................35-1
35.1.1 Definition...........................................................................................................35-135.1.2 Purposes...........................................................................................................35-135.1.3 Terms and Abbreviations...................................................................................35-1
35.2 Availability....................................................................................................................35-235.2.1 Network Elements Required..............................................................................35-235.2.2 Software Release..............................................................................................35-335.2.3 Miscellaneous....................................................................................................35-3
35.3 Impact..........................................................................................................................35-435.3.1 On the System Performance.............................................................................35-435.3.2 On Other Features.............................................................................................35-4
35.4 Technical Description...................................................................................................35-435.4.1 TX/RX Diversity Configuration Model................................................................35-435.4.2 RX Diversity Algorithms.....................................................................................35-635.4.3 TX Diversity Algorithms...................................................................................35-11
35.5 Capabilities................................................................................................................35-2635.6 Implementation..........................................................................................................35-27
35.6.1 Enabling TX/RX Diversity................................................................................35-2735.6.2 Reconfiguring TX/RX Diversity Parameters.....................................................35-2835.6.3 Disabling TX/RX diversity................................................................................35-28
35.7 Maintenance Information............................................................................................35-2835.7.1 Alarms.............................................................................................................35-2835.7.2 Counters..........................................................................................................35-28
35.8 References................................................................................................................. 35-29
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RAN Feature Description List of Figures
List of Figures
Figure 35-1 TX/RX Diversity configuration model (1)..........................................................35-5
Figure 35-2 TX/RX Diversity configuration model (2)..........................................................35-5
Figure 35-3 RX diversity implementation of one sector in BTS3812E...............................35-10
Figure 35-4 RX diversity implementation of one sector in DBS3800.................................35-11
Figure 35-5 TX diversity implementation of one sector in BTS3812E...............................35-20
Figure 35-6 TX diversity implementation of one sector in DBS3800.................................35-21
Figure 35-7 Structure of SCH transmitted in TSTD...........................................................35-21
Figure 35-8 STTD transmitter...........................................................................................35-22
Figure 35-9 Transmitter and receiver in closed loop transmit diversity mode....................35-23
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RAN Feature Description List of Tables
List of Tables
Table 35-1 NEs required for TX/RX diversity....................................................................35-3
Table 35-2 RAN products and related versions...................................................................35-3
Table 35-3 BTS3812E subrack information.........................................................................35-8
Table 35-4 DBS3800 subrack information...........................................................................35-9
Table 35-5 Application of TX diversity modes on downlink physical channel types...........35-11
Table 35-6 BTS3812E subrack information.......................................................................35-14
Table 35-7 BTS3812E board information..........................................................................35-15
Table 35-8 DBS3800 subrack information.........................................................................35-18
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RAN Feature Description Chapter 35 TX/RX Diversity
Chapter 35 TX/RX Diversity
35.1 Introduction
35.1.1 Definition
Signals received on radio channels are combined multipath components that reach the receiver. The signal from individual paths, if combined by the receiver, can combat fading.
Diversity is a transmission technique that enables individual signals to be combined to enhance system performance.
In the WCDMA system, diversity can be performed in two directions:
Receive diversity Transmit diversity
Based on the number of antennas, receive diversity is of two types:
2-way receive diversity 4-way receive diversity
Based on the feedback, transmit diversity is of two types:
Open loop transmit diversity (without feedback) Closed loop transmit diversity (with feedback)
Open loop transmit diversity can be further categorized into:
Space Time Transmit Diversity (STTD) Time Switched Transmit Diversity (TSTD)
35.1.2 Purposes
Diversity can improve the performance of RX channels and lower the SIR requirements for downlink signals and uplink signals.
35.1.3 Terms and Abbreviations
I. Terms
None.
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RAN Feature Description Chapter 35 TX/RX Diversity
II. Abbreviations
Abbreviation Full Spelling
AICH Acquisition Indicator Channel
CLD Closed Loop Transmit Diversity
CLD1 Closed Loop Transmit Diversity Mode 1
DPCCH Dedicated Physical Control Channel
DPCH Dedicated Physical Channel
E-AGCH E-DCH Absolute Grant Channel
E-DCH Enhanced Dedicated Channel
E-HICH E-DCH Hybrid ARQ Indicator Channel
E-RGCH E-DCH Relative Grant Channel
HS-PDSCH High Speed Physical Downlink Shared Channel
HS-SCCH Shared Control Channel for HS-DSCH
MICH MBMS Indicator Channel
PA Power Amplifier
P-CCPCH Primary Common Control Physical Channel
PICH Page Indicator Channel
PDSCH Physical Downlink Shared Channel
RNC Radio Network Controller
RX Diversity Receive Diversity
S-CCPCH Secondary Common Control Physical Channel
SCH Synchronization Channel
SIR Signal-to-Interference Ratio
SNR Signal-to-Noise Ratio
STTD Space Time Transmit Diversity
TSTD Time Switched Transmit Diversity
TX Diversity Transmit Diversity
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RAN Feature Description Chapter 35 TX/RX Diversity
Abbreviation Full Spelling
UE User Equipment
35.2 Availability
35.2.1 Network Elements Required
Table 35-1 shows the Network Elements (NEs) required for TX/RX diversity.
Table 35-1 NEs required for TX/RX diversity
UE NodeB RNC MSC Server MGW SGSN GGSN HLR
√ √ √ – – – – –
Note:
–: not required
√: required
35.2.2 Software Release
Table 35-2 describes the versions of RAN products that support TX/RX diversity.
Table 35-2 RAN products and related versions
Product Version
RNC BSC6800 V100R002 and later releases
NodeB
DBS3000 V100R006 and later releases
BTS3812A V100R005 and later releases
BTS3812E V100R005 and later releases
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RAN Feature Description Chapter 35 TX/RX Diversity
Note:
The RNC supports TSTD and STTD from V100R002 and it will support CLD mode 1 from V100R008.
Receive diversity is performed by only the NodeB to improve the performance of RX channels. It does not involve RNC or UE.
35.2.3 Miscellaneous
RX diversity requires the NodeB to provide enough RF channels and demodulation resources that can match the number of diversity antennas. It has no special requirements for RNC or UE.
TX diversity requires the NodeB to provide RF channel resources two times those of no TX diversity mode and to support STTD, TSTD, and CLD1. In TX diversity mode, the UE must support diversity reception, STTD, TSTD, and CLD1. This diversity mode has no special requirements for RNC.
35.3 Impact
35.3.1 On the System Performance
TX diversity can improve terminal performance in special circumstances, especially where there is less valid multipath effect and the UE speed is low. In such a scenario, capacity and coverage can be obviously improved and investment can be reduced while the same QoS is guaranteed and the CAPEX and OPEX can be cut down by operators.
Because there are different scenarios and motion velocities, TX diversity does not have versatility to all users with performance improvement. Whole system gain may be obvious. On the other hand, if different TX modes are set according to different cell circumstances, the handover between cells in different TX modes is complicated. The system may be decreased because of the complexity.
35.3.2 On Other Features
None.
35.4 Technical Description
35.4.1 TX/RX Diversity Configuration Model
The configuration model of TX/RX diversity is show in Figure 35-2 and Figure 35-3.
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RAN Feature Description Chapter 35 TX/RX Diversity
NodeB
CellClass
SEC.Class
Antenna Magnitude
Antenna Channel No.1
Cabinet No. of Antenna Channel1
Subrack No. of Antenna Channel1
Diversity Mode
LOCELL.Class
Cabinet No. of Antenna Channel1
Subrack No. of Antenna Channel1
Slot No. of Power Amplifier1
Cabinet No. of Antenna Channel2
Subrack No. of Antenna Channel2
Slot No. of Power Amplifier2
Cabinet No. of Power Amplifier1
Subrack No. of Power Amplifier1
Cabinet No. of Power Amplifier2
Subrack No. of Power Amplifier2
Figure 35-2 TX/RX Diversity configuration model (1)
CELLSETUP.Class
STTD support indicator
CP1 support indicator
DPCH priority Tx diversity mode
Hspdsch priority Tx diversity
Closed loop time adjust mode indication
Closed loop time adjust mode
TX diversity ind
RNC
NodeBRelatedClass
RadioClass
Figure 35-3 TX/RX Diversity configuration model (2)
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RAN Feature Description Chapter 35 TX/RX Diversity
35.4.2 RX Diversity Algorithms
I. Rake Receiver and Diversity Reception
A rake receiver is a radio receiver designed to counter the effects of multipath fading. It does this by using several "sub-receivers" each delayed slightly in order to tune in to the individual multipath components. Each component is decoded independently, but at a later stage combined in order to make the most use of the different transmission characteristics of each transmission path. This could very well result in higher SNR (or Eb/No) in a multipath environment than in a "clean" environment.
Diversity reception refers to a technique of monitoring multiple frequencies from the same signal source, or multiple radios and antennas monitoring the same frequency, in order to combat signal fade and interference.
II. Implementation of Diversity Reception
Diversity reception is one way to enhance the reception performance of uplink channels. It does not involve RNC or UE.
Huawei NodeBs support both RX diversity and no RX diversity. In RX diversity mode, the NodeB can be configured with 2 antenna (2-way), 4 antennas (4-way), and 4 antennas for economical purpose (4-way economical) through the Antenna Magnitude parameter. The only difference between 4-way and 4-way economical modes is that in the latter mode signals on the random access channel are received from two antennas, which ensures that the maximum coverage of 180 km is achieved.
In RX diversity mode, the NodeB does not require additional devices and works with the same algorithms. Compared with 1-way no RX diversity, 2-way RX diversity requires twice the number of RX channels. Similarly, 4-way RX diversity requires twice the number of RX channels compared with 2-way RX diversity. The number of RX channels depends on the settings of the antenna connectors on the cabinet top.
If Antenna Magnitude is set to no RX diversity, configure only the Antenna Channel No.1 parameter.
If Antenna Magnitude is set to 2-way RX diversity, configure the Antenna Channel No.1 and Antenna Channel No.2 parameters.
If Antenna Magnitude is set to 4-way RX diversity, configure the Antenna Channel No.1, Antenna Channel No.2, Antenna Channel No.3, and Antenna Channel No.4 parameters, cabinet number (Cabinet No. of Antenna Channel1, Cabinet No. of Antenna Channel2, Cabinet No. of Antenna Channel3, and Cabinet No. of Antenna Channel4), and subrack number (Subrack No. of Antenna Channel1, Subrack No. of Antenna Channel2, Subrack No. of Antenna Channel3, and Subrack No. of Antenna Channel4).
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RAN Feature Description Chapter 35 TX/RX Diversity
Parameter Name Antenna Magnitude
Parameter ID ANTM
GUI Range 1, 2, 4
Physical Range & Unit1, 2, 4
Unit: none
Default Value None
Optional/Mandatory Mandatory
MML Command ADD SEC MOD SEC
Description:
This parameter defines the number of receiving antennas in a sector.
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RAN Feature Description Chapter 35 TX/RX Diversity
Parameter Name Antenna Channel No.1
Parameter ID ANT1N
GUI Range
For the BTS3812E:
N0A (Cabinet No.0A Ant.), N0B (Cabinet No.0B Ant.), N1A (Cabinet No.1A Ant.), N1B (Cabinet No.1B Ant.), N2A (Cabinet No.2A Ant.), N2B (Cabinet No.2B Ant.), N3A (Cabinet No.3A Ant.), N3B (Cabinet No.3B Ant.), N4A (Cabinet No.4A Ant.), N4B (Cabinet No.4B Ant.), N5A (Cabinet No.5A Ant.), N5B (Cabinet No.5B Ant.), R0A (RRU No. 0A Ant.), R0B (RRU No. 0B Ant.)
For the DBS3800:
R0A (RRU No. 0A Ant.), R0B (RRU No. 0B Ant.), R1A (RRU No. 1A Ant.), R1B (RRU No. 1B Ant.)
Physical Range & UnitSame as above
Unit: none
Default Value None
Optional/Mandatory Mandatory
MML Command ADD SEC MOD SEC
Description:
This parameter defines the numbered antenna connectors on the cabinet top that are associated with receiving antenna 1 of a sector.
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RAN Feature Description Chapter 35 TX/RX Diversity
Parameter Name Cabinet No. of Antenna Channel1
Parameter ID ANT1CN
GUI Range MASTER (master cabinet)
Physical Range & UnitMASTER
Unit: none
Default Value MASTER
Optional/Mandatory Mandatory
MML Command ADD SEC MOD SEC
Description:
This parameter defines the numbered cabinet that is associated with receiving antenna 1 of a sector.
Parameter Name Subrack No. of Antenna Channel1
Parameter ID ANT1SRN
GUI RangeFor the BTS3812E, refer to Table 35-1.
For the DBS3800, refer to Table 35-2.
Physical Range & UnitSame as above
Unit: none
Default ValueBTS3812E: 3
DBS3800: None
Optional/Mandatory Mandatory
MML Command ADD SEC MOD SEC
Description:
This parameter defines the numbered subracks that are associated with receiving antenna 1 of a sector.
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RAN Feature Description Chapter 35 TX/RX Diversity
Table 35-1 BTS3812E subrack information
Subrack No. Subrack Type
0 Baseband Subrack (BB)
1 Fan Subrack (FAN)
2 Transmitting and Receiving Unit Subrack (TRU)
3 Antenna Filter Unit Subrack (AFU)
6 Extension Subrack (EXT)
20–199 RRU Subrack (RRU)
Table 35-2 DBS3800 subrack information
Subrack No. Subrack Type
0–3 BBU Subrack (BBU3806)
0–1 BBU Subrack (BBU3806C)
6 Extension Subrack (EXT)
20–199 RRU Subrack (RRU)
The parameters Antenna Channel No.2, Antenna Channel No.3, and Antenna Channel No.4 are defined in a way similar to Antenna Channel No.1. They define the numbered antenna connectors associated with receiving antenna 2, 3, and 4 of a sector.
The parameters Cabinet No. of Antenna Channel2, Cabinet No. of Antenna Channel3, and Cabinet No. of Antenna Channel4 are defined in a way similar to Cabinet No. of Antenna Channel1. They define the numbered cabinet associated with receiving antennas 2, 3, and 4 of a sector.
The parameters Subrack No. of Antenna Channel2, Subrack No. of Antenna Channel3, and Subrack No. of Antenna Channel4 are defined in a way similar to Subrack No. of Antenna Channel1. They define the numbered subracks associated with receiving antennas 2, 3, and 4 of a sector.
All these parameters are optionally set.
The hardware configurations of 4-way Rx diversity per sector for different NodeB are as show in Figure 35-4 and Figure 35-5:
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RAN Feature Description Chapter 35 TX/RX Diversity
AN
T
AN
T RX
RET
MON_ANT
COM/PWR
RXA0
RXA1
RXB
TX
MAFU0
AN
T
AN
T RX
RET
MON_ANT
COM/PWR
RXA0
RXA1
RXB
TX
MAFU1
COM
TX
RXA
RXB
BBIF0
BBIF1
PWR
COM
TX
RXA
RXB
BBIF0
BBIF1
PWR
MTRU0 MTRU1
TX/RX0 RX1 RX2 RX3
F1F2
F1F2
F1F2
F1F2
Figure 35-4 RX diversity implementation of one sector in BTS3812E
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RAN Feature Description Chapter 35 TX/RX Diversity
RX filterDUP
LNA0
LNA1
MTRX
TX/RX0
RRU0
LNA0
LNA1
MTRX
RRU1
LNA
1-IN
LNA
0-O
UT
RX filterDUP
LNA
1-IN
LNA
0-O
UTRX1 RX2 RX3
F1F2
F1F2
F1F2
F1F2
HPA
HPA
Figure 35-5 RX diversity implementation of one sector in DBS3800
35.4.3 TX Diversity Algorithms
There are several transmit diversity modes adopted in WCDMA 3GPP, which are TSTD, STTD, and CLD1. TSTD and STTD are open loop transmit diversity, which do not need feedback information compared with the closed loop diversity. Table 35-1 summarizes the possible application of open and closed loop transmit diversity modes on different types of downlink physical channels.
Table 35-1 Application of TX diversity modes on downlink physical channel types
Physical Channel TypeOpen Loop Mode Closed Loop Mode
TSTD STTD Mode 1
P-CCPCH – X –
SCH X – –
S-CCPCH – X –
DPCH – X X
F-DPCH – X –
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RAN Feature Description Chapter 35 TX/RX Diversity
Physical Channel TypeOpen Loop Mode Closed Loop Mode
TSTD STTD Mode 1
PICH – X –
MICH – X –
HS-PDSCH – X X
HS-SCCH – X –
E-AGCH – X –
E-RGCH – X –
E-HICH – X –
AICH – X –
Note: X: applicable
–: not applicable
If a cell works in TX diversity mode, the CPICH, PCCPCH, and SCH channels of the cell must work in TX diversity mode too.
If a cell works in TX diversity mode, the TX diversity ind parameter is set on the RNC and the Diversity Mode parameter is set on the NodeB.
Parameter Name TX diversity ind
Parameter ID TXDIVERSITYIND
GUI Range TRUE, FALSE
Physical Range & UnitTRUE, FALSE
Unit: none
Default Value None
Optional/Mandatory Optional
MML Command MOD CELLSETUP
Description:
This parameter defines the configuration of TX diversity on the downlink common physical channels of a cell.
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RAN Feature Description Chapter 35 TX/RX Diversity
Configuration Rule and Restriction:
If the downlink common channels of a cell is configured on the RNC to support TX diversity mode, ensure that the associated local cell of the NodeB supports TX diversity.
Parameter Name Diversity Mode
Parameter ID DIVM
GUI RangeNO_TX_DIVERSITY (No Transmit Diversity), TX_DIVERSITY (Transmit Diversity), HALFFREQ (0.5/0.5 Mode)
Physical Range & UnitNO_TX_DIVERSITY, TX_DIVERSITY, HALFFREQ
Unit: none
Default Value NO_TX_DIVERSITY
Optional/Mandatory Optional
MML Command ADD SEC MOD SEC
Description:
This parameter defines the configuration of TX diversity in a sector.
When setting up the sectors of the NodeB, you can set only the Diversity Mode parameter. The RF channels to be used are defined by the following parameters when local cells are set up on the NodeB, either BTS3812E or DBS3800.
For the BTS3812E, configure the following parameters of the local cells.
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RAN Feature Description Chapter 35 TX/RX Diversity
Parameter Name Cabinet No. of Antenna Channel1
Parameter ID ANT1CN
GUI Range MASTER (master cabinet)
Physical Range & UnitMASTER
Unit: none
Default Value MASTER
Optional/Mandatory Mandatory
MML Command ADD LOCELL MOD LOCELL
Description:
This parameter defines the numbered cabinet associated with the PAs in the main path when the sector works in no TX diversity or TX diversity mode.
Parameter Name Subrack No. of Antenna Channel1
Parameter ID ANT1SRN
GUI Range Refer to Table 35-2.
Physical Range & UnitSame as above
Unit: none
Default Value None
Optional/Mandatory Mandatory
MML Command ADD LOCELL MOD LOCELL
Description:
This parameter defines the numbered subrack associated with the MTRU/RRU PAs in the main path when the sector works in no TX diversity or TX diversity mode.
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RAN Feature Description Chapter 35 TX/RX Diversity
Table 35-2 BTS3812E subrack information
Subrack No. Subrack Type
0 Baseband Subrack (BB)
1 Fan Subrack (FAN)
2 Transmitting and Receiving Unit Subrack (TRU)
3 Antenna Filter Unit Subrack (AFU)
6 Extension Subrack (EXT)
20–199 RRU Subrack (RRU)
Parameter Name Slot No. of Power Amplifier1
Parameter ID SN1
GUI Range Refer to Table 35-3.
Physical Range & UnitSame as above
Unit: none
Default Value None
Optional/Mandatory Mandatory
MML Command ADD LOCELL MOD LOCELL
Description:
This parameter defines the numbered slots that are associated with the MTRU PAs in the main path when the sector works in no TX diversity or TX diversity mode. You do not need to define the slot number if the RRU is used.
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RAN Feature Description Chapter 35 TX/RX Diversity
Table 35-3 BTS3812E board information
Cabinet No.
Subrack No.
Slot No. Board Type
0 0 0, 1
NBBI (NodeB Baseband Processing and Interface Unit)
NBOI (NodeB Baseband Processing and Optical Interface Unit)
HBBI (NodeB HSDPA Baseband Processing and Interface Unit)
HBOI (NodeB HSDPA Baseband Processing and Optical Interface Unit)
0 0 2–7HULP (NodeB HSDPA Supported Uplink Processing Unit)
0 0 8, 9
NDLP (NodeB Downlink Processing Unit)
HDLP (NodeB HSDPA Supported Downlink Processing Unit
0 0 10, 11NMPT (NodeB Main Processing & Timing Unit)
0 0 12, 13
NDTI (NodeB Digital Trunk Interface Unit)
NUTI (NodeB Universal Transport Interface Unit)
NAOI (NodeB ATM Optical Interface Unit
0 0 14NUTI (NodeB Universal Transport Interface Unit)
0 0 15
HBOI (NodeB HSDPA Baseband Processing and Optical Interface Unit)
NBOI (NodeB Baseband Processing and Optical Interface Unit)
0 0 16 NMON (NodeB Monitor Unit)
0 1 0 NFAN (NodeB Fan Box)
0 2 0–5MTRU (NodeB Multi-Carrier Transceiver Unit)
0 3 0–5MAFU (NodeB Multi-Carrier Antenna Filter Unit)
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RAN Feature Description Chapter 35 TX/RX Diversity
Cabinet No.
Subrack No.
Slot No. Board Type
0 6 0NEMU (NodeB Environment Monitoring Unit)
0 6 2 NGRU (NodeB GPS Receiver)
0 20–199 0 MRRU (Remote Radio Unit)
Parameter Name Cabinet No. of Antenna Channel2
Parameter ID ANT2CN
GUI Range MASTER (Master cabinet)
Physical Range & UnitMASTER
Unit: none
Default Value MASTER
Optional/Mandatory Mandatory
MML Command ADD LOCELL MOD LOCELL
Description:
This parameter defines the numbered cabinet associated with the PAs in the diversity path when the sector works in TX diversity mode.
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RAN Feature Description Chapter 35 TX/RX Diversity
Parameter Name Subrack No. of Antenna Channel2
Parameter ID ANT2SRN
GUI Range Refer to Table 35-2.
Physical Range & UnitSame as above
Unit: none
Default Value None
Optional/Mandatory Mandatory
MML Command ADD LOCELL MOD LOCELL
Description:
This parameter defines the numbered subrack associated with the MTRU/RRU PAs in the diversity path when the sector works in TX diversity mode.
Parameter Name Slot No. of Power Amplifier2
Parameter ID SN2
GUI Range Refer to Table 35-3.
Physical Range & UnitSame as above
Unit: none
Default Value None
Optional/Mandatory Mandatory
MML Command ADD LOCELL MOD LOCELL
Description:
This parameter defines the numbered slots that are associated with the MTRU PAs in the diversity path when the sector works in TX diversity mode. You do not need to define the slot number if the RRU is used.
For the DBS3800, configure the following parameters of the local cells.
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RAN Feature Description Chapter 35 TX/RX Diversity
Parameter Name Cabinet No. of Power Amplifier1
Parameter ID CN1
GUI Range MASTER (master cabinet)
Physical Range & UnitMASTER
Unit: none
Default Value MASTER
Optional/Mandatory Mandatory
MML Command ADD LOCELL MOD LOCELL
Description:
This parameter defines the numbered cabinet associated with the PAs in the main path when the sector works in no TX diversity or TX diversity mode.
Parameter Name Subrack No. of Power Amplifier1
Parameter ID SRN1
GUI Range Refer to Table 35-4.
Physical Range & UnitSame as above
Unit: none
Default Value None
Optional/Mandatory Mandatory
MML Command ADD LOCELL MOD LOCELL
Description:
This parameter defines the numbered subrack associated with the MTRU/RRU PAs in the main path when the sector works in no TX diversity or TX diversity mode.
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RAN Feature Description Chapter 35 TX/RX Diversity
Table 35-4 DBS3800 subrack information
Subrack No. Subrack type
0–3 BBU Subrack (BBU3806)
0–1 BBU Subrack (BBU3806C)
6 Extension Subrack (EXT)
20–199 RRU Subrack (RRU)
Parameter Name Cabinet No. of Power Amplifier2
Parameter ID CN2
GUI Range MASTER (master cabinet)
Physical Range & UnitMASTER
Unit: none
Default Value MASTER
Optional/Mandatory Mandatory
MML Command ADD LOCELL MOD LOCELL
Description:
This parameter defines the numbered cabinet associated with the PAs in the diversity path when the sector works in TX diversity mode.
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RAN Feature Description Chapter 35 TX/RX Diversity
Parameter Name Subrack No. of Power Amplifier2
Parameter ID SRN2
GUI Range Refer to Table 35-4.
Physical Range & UnitSame as above
Unit: none
Default Value None
Optional/Mandatory Mandatory
MML Command ADD LOCELL MOD LOCELL
Description:
This parameter defines the numbered subrack associated with the MTRU/RRU PAs in the diversity path when the sector works in TX diversity mode.
If a sector works in 2-way RX diversity mode and TX diversity is performed, you must set up the following hardware connections:
If two pairs of MTRUs and MAFUs are used to implement TX diversity, you must cross-connect them as follows:
- RXA1 on MAFU0 connects to RXB on MTRU1.
- RXA1 on MAFU1 connects to RXB on MTRU0.
- RXBs on both MAFUs work in suspended state.
If two RRUs are used to implement TX diversity, jumpers for cross-connection are required.
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RAN Feature Description Chapter 35 TX/RX Diversity
AN
T
AN
T RX
RET
MON_ANT
COM/PWR
RXA0
RXA1
RXB
TX
MAFU0
AN
T
AN
T RX
RET
MON_ANT
COM/PWR
RXA0
RXA1
RXB
TX
MAFU1
COM
TX
RXA
RXB
BBIF0
BBIF1
PWR
COM
TX
RXA
RXB
BBIF0
BBIF1
PWR
MTRU0 MTRU1
TX/RX0 RX1
F1F2
F1F2
Figure 35-6 TX diversity implementation of one sector in BTS3812E
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RAN Feature Description Chapter 35 TX/RX Diversity
RX filterDUP
LNA0
LNA1
MTRX
RRU0
RX filterDUP
LNA0
LNA1
MTRX
RRU1
TX/RX0
LNA
1-IN
LNA
0-O
UT
LNA
1-IN
LNA
0-O
UTRX1
F1F2
F1F2
HPA
HPA
Figure 35-7 TX diversity implementation of one sector in DBS3800
I. Time Switched Transmit Diversity
TSTD is applied on SCH only. In TSTD, the transmission is switched between different antennas with a known periodicity, as shown in Figure 35-8.
Antenna 1
Antenna 2
acsi,0
acp
acsi,1
acp
acsi,14
acp
Slot #0 Slot #1 Slot #14
acsi,2
acp
Slot #2
(Tx OFF)
(Tx OFF)
(Tx OFF)
(Tx OFF)
(Tx OFF)
(Tx OFF)
(Tx OFF)
(Tx OFF)
Figure 35-8 Structure of SCH transmitted in TSTD
TSTD is the simplest transmit diversity mode in WCDMA. The UE can receive TSTD signals with the same method as used in non-diversity mode. In this sense, the UE does not need to be aware if whether TSTD is applied or not.
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RAN Feature Description Chapter 35 TX/RX Diversity
II. Space Time Transmit Diversity
STTD is defined for two antennas. Assume that and are odd and even symbols
respectively. Then the transmissions over two antennas are shown in Figure 35-9.
S1S0
S1S0
S0*-S1
*
Antenna1
Antenna2
Figure 35-9 STTD transmitter
The received symbol may be represented in vector form as follows:
1*01101
0*11000
nShShr
nShShr
The received symbol is decoded over two consecutive time epochs with the following formula:
1*0
*011
*110
*00
ˆ
ˆ
rhrhS
rhrhS
The channel estimation is performed over pilot signals. Then the output is as follows:
1*0
*011
21
201
*110
*00
21
200
)|||(|ˆ)|||(|ˆ
nhnhShhS
nhnhShhS
On the RNC, you can set the STTD support indicator parameter for the cell that may work in STTD mode. If the cell works in STTD mode, you can set open loop transmit diversity for DPCH.
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RAN Feature Description Chapter 35 TX/RX Diversity
Parameter Name STTD support indicator
Parameter ID STTDSUPIND
GUI Range STTD Supported, STTD not Supported
Physical Range & UnitSTTD Supported, STTD not Supported
Unit: none
Default Value None
Optional/Mandatory Optional
MML Command MOD CELLSETUP
Description:
This parameter defines the STTD setting of a cell.
Configuration Rule and Restriction:
If a cell is configured to work in CLD1, ensure that the associated local cell at the NodeB side supports TX diversity.
III. Closed Loop Transmit Diversity
Closed loop transmit diversity is a technique in which the UE, a mobile station, periodically sends quantized estimations of the optimal transmit weights (so called feedback information in WCDMA) to the NodeB, a base station, through the uplink DPCCH channel. The transmitter weights are optimized to deliver maximum power to the UE. Figure 35-10 depicts the concept of closed loop transmit diversity.
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RAN Feature Description Chapter 35 TX/RX Diversity
Antenna1
Antenna2
S w1
w1
Esti mate w1 andw2 f rom pi l ots Demod Srecei ved
si gnal
Send w1 and w2to Base Stati on
Base Stati on
Mobi l e Stati on
Figure 35-10 Transmitter and receiver in closed loop transmit diversity mode
A channel model with a single path is considered and the channel fading factors from two transmitting antennas is denoted h1(t) and h2(t). Assume that the paths from two antennas are so closely spaced in time of arrival at the UE that they are indistinguishable. If time subscripts are ignored, the signals that the UE receives will be as follows:
nSww
hhr
2
121 ][ = hwS + n
The UE calculates the weights at regular intervals from the information h obtained through pilot signals to maximize the received signal power. These weights are quantized and then feedback is given to the NodeB on the reverse link control channel.
If one assumes that the feedback mechanism in closed loop transmit diversity perfectly tracks the channel conditions of the downlink, the Signal-to-Noise Ratio (SNR) after demodulation and channel estimation is bounded as follows:
0
||||0||||
|||| 22
21
2
22
21
22
21
NEshh
NEs
hh
hhSNRcld
Es/N0 is the symbol of SNR that is based solely on transmit signal energy. In comparison, from the STTD section it can be seen that the maximum achievable SNR of STTD is:
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RAN Feature Description Chapter 35 TX/RX Diversity
02|||| 2
22
1
NEshh
SNRsttd
Obviously, the maximum SNR of STTD cannot be greater than the maximum SNR of closed loop transmit diversity.
However, due to availability limitation of feedback capacity (In WCDMA, the feedback capacity is 1500b/s.), the transmit weights may not be able to track the channel conditions of the downlink perfectly, which will most probably occur when the UE moves at a high velocity. In addition, feedback information errors also deteriorate the performance of closed loop transmit diversity. Generally, closed loop transmit diversity provides the biggest gain in low velocities, while open loop methods are robust in high velocities and provides comparatively smaller gain in low velocities.
On the RNC, you can set the CP1 support indicator parameter for the cell that may work in closed loop transmit diversity mode. If the cell works in CLD1, you can set CLD1 for DPCH.
Parameter Name CP1 support indicator
Parameter ID CP1SUPIND
GUI Range CP1 Supported, CP1 not Supported
Physical Range & UnitCP1 Supported, CP1 not Supported
Unit: none
Default Value None
Optional/Mandatory Optional
MML Command MOD CELLSETUP
Description:
This parameter defines the CLD1 setting of a cell.
Configuration Rule and Restriction:
If a cell is configured to work in CLD1, ensure that the associated local cell at the NodeB side supports TX diversity.
If the cell can work in TX diversity mode, you can set two parameters (DPCH priority Tx diversity mode and Hspdsch priority Tx diversity) for the transmit diversity
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RAN Feature Description Chapter 35 TX/RX Diversity
settings of the DPCH on the RNC. The DPCH priority Tx diversity mode parameter defines the preferable transmit diversity mode of a cell when services are carried on DPCH. The Hspdsch priority Tx diversity parameter defines the preferable transmit diversity mode of the associated DPCH when services are carried on HSDPA cells.
Parameter Name DPCH priority Tx diversity mode
Parameter ID DPCHPRIOTXDIVERSITYMODE
GUI Range None, STTD, CP1
Physical Range & UnitNone, STTD, CP1
Unit: none
Default Value None
Optional/Mandatory Optional
MML Command MOD CELLSETUP
Description:
This parameter defines the preferable transmit diversity mode of DPCH.
Parameter Name Hspdsch priority Tx diversity
Parameter ID HSPDSCHPRIOTXDIVERSITYMODE
GUI Range None, STTD, CP1
Physical Range & UnitNone, STTD, CP1
Unit: none
Default Value None
Optional/Mandatory Optional
MML Command MOD CELLSETUP
Description:
This parameter defines the preferable transmit diversity mode of DPCH when HSDPA services are accessed.
For CLD1, the 3GPP defines two modes to report closed loop feedback information: j+1 and j+2. In j+1 mode, the feedback information of timeslot j is reported after the
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RAN Feature Description Chapter 35 TX/RX Diversity
first (j+1)mod15 timeslot. In j+2 mode, the feedback information of timeslot j is reported after the first (j+2)mod15 timeslot.
The modes are set on the RNC through two parameters: Closed loop time adjust mode indication and Closed loop time adjust mode. If the Closed loop time adjust mode indication parameter is set to FALSE, the NodeB processes the feedback information in j+1 mode by default.
Parameter Name Closed loop time adjust mode indication
Parameter ID CLTAMODEIND
GUI Range TRUE, FALSE
Physical Range & UnitTRUE, FALSE
Unit: none
Default Value None
Optional/Mandatory Optional
MML Command MOD CELLSETUP
Description:
This parameter defines the setting of closed loop time adjustment mode of a cell.
Parameter Name Closed loop time adjust mode
Parameter ID CLOSEDLOOPTIMEADJUSTMODE
GUI Range OFFSET1, OFFSET2
Physical Range & UnitOFFSET1 = (j+1)mod15; OFFSET2 = (j+2)mod15
Unit: slot
Default Value None
Optional/Mandatory Optional
MML Command MOD CELLSETUP
Description:
This parameter defines the time taken to adjust the phase and amplitude of DL dedicated channel upon reception of response from UL dedicated channel.
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RAN Feature Description Chapter 35 TX/RX Diversity
35.5 CapabilitiesNone
35.6 Implementation
35.6.1 Enabling TX/RX Diversity
I. Install Hardware
None.
II. Install Software
None.
III. Configure Data
To configure the data on the RNC, perform the following steps:
2) Use the ADD QUICKCELLSETUP command to quickly set up a cell.
During the quick set up of the cell, most parameters are set with their default values, which speeds up the setup procedure.
3) Use the MOD CELLSETUP command to modify TX diversity parameters of the cell.
4) Use the ACT CELL command to activate the cell.
To configure the data on the NodeB, perform the following steps:
1) Use the ADD SEC command to add a sector on the NodeB.2) Use the ADD LOCELL command to add a local cell on the NodeB.
IV. Examples
The following example is based on TX diversity in the downlink and 2-way RX diversity in the uplink.
To configure the data, perform the following steps:
1) Configure sectors on the NodeB.
TX diversity is applied in the downlink, 2-way RX diversity is applied in the uplink, and the receiving antennas are specified.
3) Configure local cells on the NodeB, and configure the resources of TX channels in main and diversity paths according to the TX diversity mode of the sector.
4) Quickly set up a cell on the RNC.5) Modify TX diversity parameters of the cell on the RNC.6) Activate the cell.
//Set up a local cell on the NodeB through the following command:
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RAN Feature Description Chapter 35 TX/RX Diversity
ADD SEC: STN=0, SECN=1, SECT=LOCAL_SECTOR, ANTM=2, DIVM=TX_DIVERSITY,
ANT1SRN=3, ANT1N=N0A, ANT2SRN=3, ANT2N=N1A;
ADD LOCELL: LOCELL=0, STN=0, SECN=1, SECT=LOCAL_SECTOR,
BBPOOLTYPE=GEN_POOL, SRN1=2, SN1=0, SRN2=2, SN2=1, ULFREQ=9850,
DLFREQ=10800, HISPM=FALSE, MXPWR=430;
//Set up the cell on the RNC quickly, and modify its parameters after the cell is set up.
ADD QUICKCELLSETUP: CellId=110, CellName="cell110", BandInd=Band1,
UARFCNUplink=9850, UARFCNDownlink=10800, PScrambCode=110, TCell=CHIP256,
LAC=9479, SAC=1, CfgRacInd=REQUIRE, RAC=1, URANUM=D1, URA1=1,
NodeBName="3812E104", LoCell=0, SupBmc=FALSE;
MOD CELLSETUP: CellId=110, SupSSDT=TRUE, TxDiversityInd=TRUE,
DpchTxDiversityMode=STTD, HsPdschTxDiversityMode=STTD, CLTAModeInd=TRUE,
ClosedLoopTimeAdjustMode=OFFSET1;
ACT CELL: CellId=110;
V. Verify the Enabled Feature
Use the UE that supports TX diversity to send a service setup request message. Then check the diversity settings of related channels during the signaling procedure.
35.6.2 Reconfiguring TX/RX Diversity Parameters
To reconfigure the diversity settings of a cell, perform the following steps:
7) Deactivate the logical cell that is associated with the local cell on the NodeB that requires reconfiguration.
8) Use the MOD SEC command to modify the diversity settings of the sector.9) Use the MOD LOCELL command to modify the diversity settings of the local cell.10) Activate the logical cell.
35.6.3 Disabling TX/RX diversity
To change RX diversity mode to no RX diversity mode, set the Antenna Magnitude parameter to 1. For details, refer to step 2 in section 35.6.2 "Reconfiguring TX/RXDiversity Parameters".
To change TX diversity mode to no TX diversity mode, use the MOD CELLSETUP command to set the TX diversity ind parameter to FALSE on the RNC.
35.7 Maintenance Information
35.7.1 Alarms
None.
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RAN Feature Description Chapter 35 TX/RX Diversity
35.7.2 Counters
None.
35.8 References 3GPP TS 25.211, “Physical channels and mapping of transport channels onto
physical channels (FDD), V6.7.0”. 3GPP TS 25.211, “Physical layer procedures (FDD), V6.9.0”.
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