56699897 wcdma-ran-planning-and-optimization-features-and-algorithms

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Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
WCDMA UE Behaviors
in Idle Mode
1

Foreword
UE behaviors in idle mode include :
PLMN selection
System information reception
Cell selection and reselection
Location registration
Paging procedure
Access procedure
PLMN selection
Used to ensure that the PLMN selected by the UE properly provides services.
Cell selection and reselection
Used to ensure that the UE finds a suitable cell to camp on.
Location registration
Used for the network to trace the current status of the UE and to ensure that the UE is camped
on the network when the UE does not perform any operation for a long period.
System information reception
The network broadcasts the network information to a UE which camps on the cell to control the
behaviors of the UE.
Paging
Used for the network to send paging messages to a UE which is in idle mode, CELL_PCH
state, or URA_PCH state.
Access
From the view of access stratum, access is the procedure UE shift from idle mode to
connected mode.
2

Contents
1. PLMN Selection
2. System Information Reception
3. Cell Selection and Reselection
4. Location Registration
5. Paging Procedure
6. Access Procedure
3

Contents
1. PLMN Selection
5. Paging Procedure
6. Access Procedure
4

Cell Search
UE does not have UTRAN carrier information
In order to find a suitable cell to stay, UE will scan all the
frequencies in UTRAN. In each carrier, UE just need to find a
cell with best signal
UE has UTRAN carrier information
UE will try whether the original cell is suitable to stay. If not, UE
still need to scan all the frequencies about UTRAN in order to
find a suitable cell in PLMN
Typical scenario of first occasion is the first time a new UE is put into use.
The second occasion is very common.
5

Cell Search
Slot synchronization
Frame synchronization and
code-group identification
Primary Scrambling code
identification
Step 1: Slot synchronization
During the first step of the cell search procedure the UE uses the primary synchronisation code
(PSC) to acquire slot synchronisation to a cell.
Step 2: Frame synchronization and code-group identification
During the second step of the cell search procedure, the UE uses the secondary
synchronisation code (SSC) to find frame synchronisation and identify the code group of the
cell found in the first step.
Step 3: Primary Scrambling code identification:
During the last step of the cell search procedure, the UE determines the exact primary
scrambling code used by the found cell. The primary scrambling code is typically identified
through symbol-by-symbol correlation over the CPICH with all codes within the code group
identified in the second step.
If the UE has received information about which scrambling codes to search for, steps 2 and 3
above can be simplified.
6

PLMN Selection
UE shall maintain a list of allowed PLMN types. In the
PLMN list, the UE arranges available PLMNs by priorities.
When selecting a PLMN, it searches the PLMNs from the
high priority to the low.
The UE selects a PLMN from HPLMNs or VPLMNs.
UE can get the system information from PCCPCH, and the PLMN information is transmitted in
MIB of PCCPCH
After getting the MIB, UE can judge weather the current PLMN is the right one. If so, UE will
get the SIB scheduling information from the MIB; if not, UE will search another carrier, do this
procedure again
7

PLMN Selection (Cont.)
PLMN Selection in HPLMNs
Automatic PLMN Selection Mode
The UE selects an available and suitable PLMN from the whole
band according to the priority order
Manual PLMN Selection Mode
The order of manual selection is the same as that of automatic
selection.
The priority order for automatic PLMN selection mode
The PLMN selected by the
UE before automatic PLMN
selection
Previously selected PLMN6
The PLMNs are arranged in
descending order of signal
quality.
Other PLMN/access technology combinations
excluding the previously selected PLMN
5
random order
Other PLMN/access technology combinations with
the high quality of received signals excluding the
previously selected PLMN
4
priority order
PLMNs contained in the "Operator Controlled
PLMN Selector with Access Technology" data field
in the SIM excluding the previously selected PLMN
3
priority order
PLMNs contained in the "User Controlled PLMN
Selector with Access Technology" data field in the
SIM excluding the previously selected PLMN
2
Home PLMNsHPLMNs1
RemarkPLMN typeOrder
8

PLMN Selection (Cont.)
PLMN Selection in VPLMNs
If a UE is in a VPLMN, it scans the “user controlled PLMN
selector” field or the “operator controlled PLMN selector” field
in the PLMN list to find the HPLMN or the PLMN with higher
priority according to the requirement of the automatic PLMN
selection mode.
A value of T minutes may be stored in the SIM. T is either in the range from 6 minutes to 8
hours in 6-minute steps or it indicates that no periodic attempts shall be made. If no value is
stored in the SIM, a default value of 60 minutes is used.
After the UE is switched on, a period of at least 2 minutes and at most T minutes shall elapse
before the first attempt is made.
The UE shall make an attempt if the UE is on the VPLMN at time T after the last attempt.
9

Contents
1. PLMN Selection
5. Paging Procedure
6. Access Procedure
10

Structure of System Information
System information is organized as a tree, including:
MIB (Master Information Block )
SB (Scheduling Block )
SIB (System Information Block )
System information is used for the network to broadcast network information to UEs camping
on a cell so as to control the behavior of UEs.
MIB
When selecting a new cell, the UE reads the MIB. The UE may locate the MIB by
predefined scheduling information. The IEs in the MIB includes MIB value tag, PLMN
type, PLMN identity, reference and scheduling information for a number of SIBs in a
cell or one or two SBs in a cell.
SB
Scheduling Block (SB) gives reference and scheduling information to other SIBs. The
scheduling information of a SIB may be included in only one of MIB and SB.
SIB
System Information Block (SIB) contains actual system information. It consists of
system information elements (IEs) with the same purpose.
Scheduling information for a system information block may only be included in either the
master information block or one of the scheduling blocks.
11

System Information
SIB1: Contains the system information for NAS and the
timer/counter for UE
SIB2: Contains the URA information
SIB3: Contains the parameters for cell selection and cell re-
selection
SIB5: Contains parameters for the common physical channels of
the cell
SIB7: Contains the uplink interference level and the refreshing
timer for SIB7
SIB11: Contains measurement controlling information
SIB4: Contains parameters for cell selection and cell re-selection while UE is in connected
mode
SIB6: Contains parameters for the common physical channels of the cell while UE is in
connected mode
SIB8: Contains the CPCH static information
SIB9: Contains the CPCH dynamic information
SIB10: Contains information to be used by UEs having their DCH controlled by a DRAC
procedure. Used in FDD mode only. To be used in CELL_DCH state only. Changes so often,
its decoding is controlled by a timer
SIB12: Contains measurement controlling information in connecting mode
SIB13: Contains ANSI-41 system information
SIB14: Contains the information in TDD mode
SIB15: Contains the position service information
SIB16: Contains the needed pre-configuration information for handover from other RAT to
UTRAN
SIB17: Contains the configuration information for TDD
SIB18: Contains the PLMN identities of the neighboring cells
To be used in shared networks to help with the cell reselection process
12

Reception of System Information
The UE shall read system information broadcast on a BCH
transport channel when the UE is in idle mode or in
connected mode, that is, in CELL_FACH, CELL_PCH, or
URA_PCH state.
The UE may use the scheduling information in MIB and SB to locate each SIB to be acquired.
If the UE receives a SIB in a position according to the scheduling information and consider the
content valid, it will read and store it.
13

Contents
1. PLMN Selection
5. Paging Procedure
6. Access Procedure
14

Cell Selection
When the PLMN is selected and the UE is in idle mode, the
UE starts to select a cell to camp on and to obtain services.
There are four states involved in cell selection:
Camped normally
Any cell selection
Camped on any cell
Connected mode
Camped normally: The cell that UE camps on is called the suitable cell. In this state, the UE
obtains normal service.
Any cell selection: In this state, the UE shall attempt to find an acceptable cell of an any PLMN
to camp on, trying all RATs that are supported by the UE and searching first for a high quality
cell
Camped on any cell: The cell that UE camps on is called the acceptable cell. In this state the
UE obtains limited service. The UE shall regularly attempt to find a suitable cell of the selected
PLMN, trying all RATs that are supported by the UE.
Connected mode: When returning to idle mode, the UE shall use the procedure Cell selection
when leaving connected mode in order to find a suitable cell to camp on and enter state
Camped normally. If no suitable cell is found in cell reselection evaluation process, the UE
enters the state Any cell selection.
15

Cell Selection (Cont.)
Two types of cell selection:
Initial cell selection
If no cell information is stored for the PLMN, the UE starts this
procedure.
Stored information cell selection
If cell information is stored for the PLMN, the UE starts this
procedure.
Initial cell selection: If no cell information is stored for the PLMN, the UE starts the initial cell
selection. For this procedure, the UE need not know in advance which Radio Frequency (RF)
channels are UTRA bearers. The UE scans all RF channels in the UTRA band according to its
capabilities to find a suitable cell of the selected PLMN. On each carrier, the UE need only
search for the strongest cell. Once a suitable cell is found, this cell shall be selected.
Stored information cell selection: For this procedure, the UE need know the central frequency
information and other optional cell parameters that are obtained from the measurement control
information received before, such as scrambling codes. After this procedure is started, the UE
selects a suitable cell if it finds one. Otherwise, the "Initial cell selection" procedure is triggered.
16

Cell Selection Criteria
minqualqualmeasqual QQS −=
oncompensatirxlevrxlevmeasrxlev PQQS −−= min
Criterion S is used by the UE to judge whether the cell is
suitable to camped on.
Criterion S : Srxlev > 0 & Squal > 0, where:
If the pilot strength and quality of one cell meet S criteria, UE will stay in this cell and get other
system information. Then, UE will initiate a location update registration process.
If the cell doesn’t satisfy S criteria, UE will get adjacent cells information from SIB11. Then, UE
will judge weather these cells satisfy S criteria. If the adjacent cell is suitable, UE will stay in
the adjacent cell.
If no cell satisfies S criteria, UE will take the area as dead zone and continue the PLMN
selection and reselection procedure.
Max（UE_TXPWR_MAX_RACH-P_MAX，0）, dBmPcompensation
Maximum TX power level an UE may use when accessing the cell on
RACH (read in system information) (dBm)
UE_TXPWR_
MAX_RACH
Maximum RF output power of the UE (dBm)P_MAX
Minimum required RX level in the cell (dBm)Qrxlevmin
Minimum required quality level in the cell (dB)Qqualmin
Measured cell RX level value. This is received signal, CPICH RSCP for
current cells (dBm)
Qrxlevmeas
Measured cell quality value. The quality of the received signal expressed in
CPICH Ec/N0 (dB) for current cell
Qqualmeas
Cell RX level value (dBm)Srxlev
Cell quality value (dB)Squal
ExplanationParameters
17

Parameters of S Criterion
QUALMEAS
Parameter name: Cell Se-reselection quality measure
Recommended value: CPICH_ECNO
QQUALMIN
Parameter name: Min quality level
Recommended value: -18, namely -18dB
QUALMEAS
Parameter name: Cell Sel-reselection quality measure
Value range: CPICH_ECNO(CPICH Ec/N0),CPICH_RSCP(CPICH RSCP)
Physical unit: None.
Content: Cell selection and reselection quality measure, may be set to CPICH Ec/N0
or CPICH RSCP.
Recommended value: CPICH_ECNO.
QQUALMIN
Parameter name: Min quality level
Value range: -24~0
Physical value range: -24~0; step: 1
Physical unit: dB
Content: The minimum required quality level corresponding to CPICH Ec/No. The UE
can camp on the cell only when the measured CPICH Ec/No is greater than the value
of this parameter.
Recommended value: -18
Set this parameter through ADD CELLSELRESEL, query it through LST
CELLSELRESEL, and modify it through MOD CELLSELRESEL.
18

Parameters of S Criterion
QRXLEVMIN
Parameter name: Min Rx level
Recommended value: -58, namely -115dBm
MAXALLOWEDULTXPOWER
Parameter name: Max allowed UE UL TX power
Recommended value: 21, namely 21dBm
QRXLEVMIN
Parameter name: Min Rx level
Value range: -58~-13.
Physical value range: -115~-25; step: 2 (-58:-115; -57:-113; ..., -13:-25 ).
Physical unit: dBm.
Content: The minimum required RX level corresponding to CPICH RSCP. The UE can
camp on the cell only when the measured CPICH RSCP is greater than the value of
this parameter.
Recommended value: -58.
MAXALLOWEDULTXPOWER
Value range: -50~33
Physical value range: -50~33; step: 1
Physical unit: dBm
Content: The maximum allowed uplink transmit power of a UE in the cell, which is
related to the network planning. Content: Allowed maximum power transmitted on
RACH in the cell. It is related to network planning.
19

Cell Reselection
After selecting a cell and camping on it, the UE periodically
searches for a better cell according to the cell reselection
criteria. If finding such a cell, the UE selects this cell to
camp on.
UE should monitor the quality of current cell and neighbor cells in order to camp on the better
cell to initiate service. The better cell is the most suitable one for the UE to camp on and obtain
services. The QoS of this cell is not necessarily more satisfying.
20

Measurement Start Criteria (Cont.)
Intra-frequency measurement
Squal ≤ Sintrasearch
↓
Qqualmeas − Qqualmin ≤ Sintrasearch
↓
Qqualmeas ≤ Qqualmin + Sintrasearch
Parameters of the measurement start criteria
Minimum required quality level in the cell (dB) .Qqualmin
Measurement threshold for UE to trigger inter-RAT cell reselection,
compared with Squal.
SsearchRATm
Measurement threshold for UE to trigger inter-frequency cell reselection,
Sintersearch
Measurement threshold for UE to trigger intra-frequency cell reselection,
Sintrasearch
DescriptionName
21

Inter-frequency measurement
Squal ≤ Sintersearch
↓
Qqualmeas − Qqualmin ≤ Sintersearch
↓
Qqualmeas ≤ Qqualmin + Sintersearch
SsearchRATm
Sintersearch
Sintrasearch
DescriptionName
22

Inter-RAT measurement
Squal ≤ SsearchRATm
↓
Qqualmeas − Qqualmin ≤ SsearchRATm
↓
Qqualmeas ≤ Qqualmin + SsearchRATm
SsearchRATm
Sintersearch
Sintrasearch
DescriptionName
23

Parameters of Measurement Start Criteria
IDLESINTRASEARCH
Parameter name: Intra-freq cell reselection threshold for idle
mode
Recommended value: None
CONNSINTRASEARCH
Parameter name: Intra-freq cell reselection threshold for
connected mode
IDLESINTRASEARCH
Parameter name: Intra-freq cell reselection threshold for idle mode
Value range: {{-16~10},{127}} .
Physical value range: -32~20; step: 2.
Physical unit: dB.
Content: A threshold for intra-frequency cell reselection in idle mode. When the quality
(CPICH Ec/No measured by UE) of the serving cell is lower than this threshold plus
the [Qqualmin] of the cell, the intra-frequency cell reselection procedure will be started.
Recommended value: None.
CONNSINTRASEARCH
Parameter name: Intra-freq cell reselection threshold for connected mode
Value range: {{-16~10},{127}} .
Physical unit: dB
Content: A threshold for intra-frequency cell reselection in connect mode. When the
quality (CPICH Ec/No measured by UE) of the serving cell is lower than this threshold
plus the [Qqualmin] of the cell, the intra-frequency cell reselection procedure will be
started.
24

IDLESINTERSEARCH
Parameter name: Inter-freq cell reselection threshold for idle
mode
CONNSINTERSEARCH
Parameter name: Inter-freq cell reselection threshold for
connected mode
IDLESINTERSEARCH
Parameter name: Inter-freq cell reselection threshold for idle mode
Value range: {{-16~10},{127}} .
Physical unit: dB.
Content: A threshold for inter-frequency cell reselection in idle mode. When the quality
(CPICH Ec/No measured by UE) of the serving cell is lower than this threshold plus
the [Qqualmin] of the cell, the inter-frequency cell reselection procedure will be started.
CONNSINTERSEARCH
Parameter name: Inter-freq cell reselection threshold for connected mode
Value range: {{-16~10},{127}} .
Physical unit: dB
Content: A threshold for inter-frequency cell reselection in connect mode. When the
quality (CPICH Ec/No measured by UE) of the serving cell is lower than this threshold
plus the [Qqualmin] of the cell, the inter-frequency cell reselection procedure will be
started.
25

SSEARCHRAT
Parameter name: Inter-RAT cell reselection threshold
SSEARCHRAT
Parameter name: Inter-RAT cell reselection threshold
Value range: {{-16~10},{127}} .
Physical unit: dB.
Content: A threshold for inter-RAT cell reselection. When the quality (CPICH Ec/No
measured by UE) of the serving cell is lower than this threshold plus the [Qqualmin] of
the cell, the inter-RAT cell reselection procedure will be started.
26

Measurement Start Criteria Description
The intra-frequency, inter-frequency, and inter-RAT measurement criteria are as shown in the
figure.
Usually, Sintrasearch > Sintersearch > SsearchRATm
27

Cell Reselection Criteria
Criterion R is used for intra-frequency, inter-frequency cells
and inter-RAT cell reselection.
The cell-ranking criterion R is defined by :
nsoffsetnmeasn QQR ,, −=
hystssmeass QQR += ,
The cells are ranked according to R criteria specified above ,deriving QQmeas,nmeas,n and QQmeas,smeas,s and
calculating R value.
In Rs, s means serving cell. In Rn, n means neighbor cell.
The offset Qoffset1s,n is used for Qoffsets,n to calculate Rn. The hysteresis Qhyst1s is used
for Qhysts to calculate Rs.
If a TDD or GSM cell is ranked as the best cell, the UE shall reselect that TDD or GSM cell.
If an FDD cell is ranked as the best cell and the quality measure for cell selection and
reselection is set to CPICH RSCP, the UE shall reselect that FDD cell.
If an FDD cell is ranked as the best cell and the quality measure for cell selection and
reselection is set to CPICH Ec/N0, the UE shall perform a second ranking of the FDD cells
according to the R criteria specified above.
In this case, however, the UE uses the measurement quantity CPICH Ec/N0 for deriving the
Qmeas,n and Qmeas,s and then calculating the R values of the FDD cells. The offset
Qoffset2s,n is used for Qoffsets,n to calculate Rn, the hysteresis Qhyst2s is used for Qhysts to
calculate Rs.
28

Hysteresis and Time Interval
Time
Treselection
Quality
Rn
Rs
Qmeas,n
Qmeas,s
Qhyst,s
Qoffsets,n
In all the previous cases, the UE can reselect a new cell only when the following conditions are
met:
The new cell is better ranked than the serving cell during a time interval Treselection.
More than one second has elapsed since the UE camped on the current serving cell.
29

Parameters of R Criteria
IDLEQHYST1S
Parameter name: Hysteresis 1 for idle mode
Recommended value: 2, namely 4dB
CONNQHYST1S
Parameter name: Hysteresis 1 for connect mode
Recommended value: 2, namely 4dB
IDLEQHYST1S
Value range: 0~20.
Physical value range: 0~40; step: 2.
Physical unit: dB.
Content: The hysteresis value in idle mode for serving FDD cells in case the quality
measurement for cell selection and reselection is set to CPICH RSCP. It is related to
the slow fading feature of the area where the cell is located. The greater the slow
fading variance is, the greater this parameter.
Recommended value: 2.
CONNQHYST1S
Parameter name: Hysteresis 1 for connected mode
Value range: 0~20.
Physical unit: dB.
Content: The hysteresis value in connect mode for serving FDD cells in case the
quality measurement for cell selection and reselection is set to CPICH RSCP. It is
related to the slow fading feature of the area where the cell is located. The greater the
slow fading variance is, the greater this parameter.
30

Parameters of R Criteria (Cont.)
IDLEQHYST2S
Recommended value: Qhyst1s for idle mode
CONNQHYST2S
Recommended value: Qhyst1s for connected mode.
IDLEQHYST2S
Value range: {{0~20},{255}} .
Physical unit: dB.
Content: The hysteresis value in idle mode for serving FDD cells in case the quality
measurement for cell selection and reselection is set to CPICH Ec/No. It is related to the slow
fading feature of the area where the cell is located. The greater the slow fading variance is, the
greater this parameter. It is optional. If it is not configured, [Hysteresis 1] will be adopted as the
value.
Recommended value: Qhyst1s for idle mode .
Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and
modify it through MOD CELLSELRESEL.
CONNQHYST2S
Value range: {{0~20},{255}} .
Physical unit: dB.
Content: The hysteresis value in connect mode for serving FDD cells in case the quality
measurement for cell selection and reselection is set to CPICH RSCP. It is related to the slow
fading feature of the area where the cell is located. The greater the slow fading variance is, the
greater this parameter.
Recommended value: Qhyst1s for connected mode. .
Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and
modify it through MOD CELLSELRESEL.
31

TRESELECTIONS
Parameter name: Reselection delay time
Recommended value: 1, namely 1s.
TRESELECTIONS
Parameter name: Reselection delay time
Value range: 0~31 .
Physical unit: s.
Content: If the signal quality of a neighboring cell is better than the serving cell during
the specified time of this parameter, the UE will reselect the neighboring cell. It is used
to avoid ping-pong reselection between different cells. Note: The value 0 corresponds
to the default value defined in the protocol.
32

IDLEQOFFSET1SN
Parameter name: IdleQoffset1sn
Recommended value: 0, namely 0dB.
CONNQOFFSET1SN
Parameter name: ConnQoffset1sn
IDLEQOFFSET1SN
Offset of cell CPICH RSCP measurement value in cell selection or reselection when the UE is in
idle mode
Value range: -50 to +50 .
Physical value range: -50 to +50; step: 1.
Physical unit: dB.
Content: This parameter is used for moving the border of a cell. The larger the value of this
parameter, the lower the probability of neighboring cell selection.
Set this parameter through ADD INTRAFREQNCELL / ADD INTERFREQNCELL, query it
through LST INTRAFREQNCELL / LST INTERFREQNCELL, and modify it through MOD
INTRAFREQNCELL / MOD INTERFREQNCELL.
CONNQOFFSET1SN
connected mode
Physical value range: -50 to +50 ; step: 1.
Physical unit: dB.
33

IDLEQOFFSET2SN
CONNQOFFSET2SN
IDLEQOFFSET2SN
Offset of cell CPICH Ec/No measurement value in cell selection or reselection when the UE is in
idle mode
Physical value range: -50 to +50; step: 1.
Physical unit: dB.
CONNQOFFSET2SN
connected mode
Physical value range: -50 to +50 ; step: 1.
Physical unit: dB.
34

Contents
1. PLMN Selection
5. Paging Procedure
6. Access Procedure
35

Location Registration
The location registration includes:
Location update (for non-GPRS)
Route update (for GPRS)
The location registration is used for the PLMN to trace the current status of the UE and to
ensure that the UE is connected with the network when the UE does not perform any operation
for a long period.
36

Periodic Location Registration
Periodic location registration is controlled by a Periodic
Location Update timer (T3212) or a Periodic Routing Area
Update timer (T3312)
Periodic location registration may be used to periodically notify the network of the availability of
the UE.
T3212 is for non-GPRS operation
T3312 is for GPRS operation
37

Parameters of Location Registration
T3212
Parameter name: Periodical location update timer [6min]
Recommended value: 10, namely 60min
ATT
Parameter name: Attach/detach indication
Recommended value: ALLOWED
T3212
Parameter name: Periodical location update timer [6min]
Value range: 0~255.
Physical unit: 6 min.
Content: This parameter indicates the time length of the periodical location update.
Periodical location update is implemented by MS through the location update
procedure. 0: The periodical update procedure is not used. This parameter is valid only
when [CN domain ID] is set as CS_DOMAIN.
Set this parameter through ADD CNDOMAIN, query it through LST CNDOMAIN,
modify it through MOD CNDOMAIN.
ATT
Parameter name: Attach/detach indication
Value range: NOT_ALLOWED, ALLOWED .
Content: NOT_ALLOWED indicates that MS cannot apply the IMSI attach/detach
procedure. ALLOWED indicates that MS can apply the IMSI attach/detach procedure.
This parameter is valid only when [CN domain ID] is set as CS_DOMAIN.
Recommended value: ALLOWED.
Set this parameter through ADD CNDOMAIN, query it through LST CNDOMAIN,
38

Contents
1. PLMN Selection
5. Paging Procedure
6. Access Procedure
39

Paging Initiation
CN initiated paging
Establish a signaling connection
UTRAN initiated paging
Trigger the cell update procedure
Trigger reading of updated system information
For CN originated paging:
In order to request UTRAN connect to UE, CN initiates the paging procedure,
transmits paging message to the UTRAN through Iu interface, and UTRAN transmits
the paging message from CN to UE through the paging procedure on Uu interface,
which will make the UE initiate a signaling connection setup process with the CN.
For UTRAN originated paging:
When the cell system message is updated: When system messages change, the
UTRAN will trigger paging process in order to inform UE in the idle, CELL_PCH or
URA_PCH state to carry out the system message update, so that the UE can read the
updated system message.
UE state transition: In order to trigger UE in the CELL_PCH or URA_PCH state to
carry out state transition (for example, transition to the CELL_FACH state), the UTRAN
will perform a paging process. Meanwhile, the UE will initiate a cell update or URA
update process, as a reply to the paging.
40

Paging Type 1
If UE is in CELL_PCH,URA_PCH or IDLE state，the paging
message will be transmitted on PCCH with paging type 1
CN RNC1 RNC2 NODEB1.1 NODEB2.1 UE
RANAPRANAP
RANAP RANAP
PCCH: PAGING TYPE 1
PAGING
PAGING
PCCH: PAGING TYPE 1
Paging type 1:
The message is transmitted in one LA or RA according to LAI or RAI.
After calculating the paging time, the paging message will be transmitted at that time
If UE is in CELL_PCH or URA_PCH state, the UTRAN transmits the paging
information in PAGING TYPE 1 message to UE. After received paging message, UE
performs a cell update procedure to transit state to CELL_FACH.
As shown in the above figure, the CN initiates paging in a location area (LA), which is covered
by two RNCs. After receiving a paging message, the RNC searches all the cells corresponding
to the LAI, and then calculates the paging time, at which it will send the PAGING TYPE 1
message to these cells through the PCCH.
41

Paging Type 2
If UE is in CELL_DCH or CELL_FACH state，the paging
message will be transmitted on DCCH with paging type 2
CN SRNC UE
RANAPRANAP
PAGING
RRCRRC
DCCH: PAGING TYPE 2
Paging type 2:
If UE is in CELL_DCH or CELL_FACH state，the paging message will be transmitted
on DCCH with paging type 2
The message will be only transmitted in a cell
As shown in the above figure, if the UE is in the CELL_-DCH or CELL_FACH state, the
UTRAN will immediately transmit PAGING TYPE 2 message to the paged UE on DCCH
channel.
42

Typical Call Flow of UE
UE NAS UE AS NSS MSC
paging
AUTHENTICATION REQUEST
AUTHENTICATION RESPONSE
RR_SECURITY_CONTROL_REQ
(IK CK)
Security mode control
SETUP
CALL CONFIRM
ALERT
CONNECT
CONNECT ACKNOWLEDGE
RAB setup process
paging
RR_EST_REQ (PAGING RESPONSE)
RR_PAING_IND
INITIAL_DIRECT_TRANSFER
(PAGING RESPONSE)
RANAPRANAP
RRC setup process
Many problems will cause the target UE cannot receive the paging message properly
Power setting of paging channel is unreasonable.
Unreasonable paging strategies will result in paging channel congestion, which can
cause paging message loss.
Paging parameter is unreasonable
Equipment fault
43

DRX Procedure
UE receives the paging indicator on PICH periodically, that
is the Discontinuous Reception (DRX)
The value for the DRX paging cycle length is determined as
follows: :
DRX Cycle Length ＝ (2^K)×PBP frames
In idle mode, the UE can monitor the paging in two modes: one is to decode SCCPCH directly
every 10ms, the other is to decode the PICH periodically. The second one is the DRX, which is
Discontinuous Reception Mechanism.
The paging period formula:
DRX Cycle Length ＝ (2^K)*PBP frames
K is the “CN domain specific DRX cycle length coefficient”, which is broadcasted in
SIB1. The typical value is 6.
PBP is paging block period, which is 1 for FDD mode
The paging period should be 640ms if K is 6
44

DRX Procedure (Cont.)
Through DRX, UE only listens to PICH at certain predefined
time. And UE will read the paging information on SCCPCH if
the paging indicator is 1.
The value of the Paging Occasion is determined as follows:
Paging Occasion (CELL SFN) =
{(IMSI mod M) mod (DRX cycle length div PBP)} * PBP
+ n * DRX cycle length + Frame Offset
Paging SFN formula:
Paging Occasion (CELL SFN) = {(IMSI mod M) mod (DRX cycle length div PBP)}
*PBP + n *DRX cycle length + Frame Offset
n =0, 1, 2……and the requirement is the calculated CELL SFN must be below its
maximum value 4096
Frame Offset is 0 for FDD mode
M is the number of SCCPCH which carries PCH, and the typical value is 1
The formula cloud be simplified as: SFN = IMSI mod (2^K) + n * (2^K)
45

⎣ ⎦ ⎣ ⎦ ⎣ ⎦( )( )( ) Np
Np
SFNSFNSFNSFNPIq mod
144
144mod512/64/8/18 ⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
⎥⎦
⎥
⎢⎣
⎢
×+++×+=
UE must calculate q to know which PI to monitor in one
frame of PICH
The q value is achieved by the following formula :
Where, PI = (IMSI div 8192) mod NP
SFN is the paging occasion of the UE
As shown in the followed figure, the UE needs to monitor the frames (paging occasions)
indicated by the red dots, and then decodes the qth PI of this frame.
¡ £¡ £¡ £
0
2^K-1
0 4095
¡ £¡ £¡ £
PI PI PI PI¡ £¡ £¡ £¡ £¡ £¡ £
0 1 q NP-1
One DRX cycle
46

τPICH
Associated S-CCPCH frame
PICH frame containing paging indicator
Time offset between PICH and S-CCPCH
The timing relationship between PICH and S-CCPCH is defined by the above figure, and the
interval is 3 slots duration (2ms, 7680 chips).
47

Parameters of DRX
DRXCYCLELENCOEF
Parameter name: DRX cycle length coefficient
Recommended value: 6
PICHMODE
Parameter name: PICH mode
Recommended value: V36.
DRXCYCLELENCOEF
Parameter name: DRX cycle length coefficient
Value range: 6~9 .
Content: This parameter is broadcasted on SIB1. This parameter is used when a UE is
in idle mode.
Set this parameter through ADD CNDOMAIN, query it through LST CNDOMAIN, and
PICHMODE
Parameter name: PICH mode
Value range: V18, V36, V72, V144 .
Physical value range: 18, 36, 72, 144 .
Content: Indicating the number of PIs contained in each frame on the PICH.
Recommended value: V36 .
Set this parameter through ADD PICH, query it through LST PICH.
48

Parameters of DRX
MACCPAGEREPEAT
Parameter name: Number of page re-TX
MACCPAGEREPEAT
Parameter name: Number of page re-TX
Number of retransmissions of paging message
Value range: 0~2 .
Content: If the number of retransmissions of paging message exceeds this parameter
value, retransmissions stop.
Set this parameter through SET WFMRCFGDATA, query it through LST
WFMRCFGDATA.
49

Contents
1. PLMN Selection
5. Paging Procedure
6. Access Procedure
50

Two Working Mode of UE
Idle mode
After turning on, UE will stay in idle mode
Connected mode
UE will switch to connected mode which could be CELL_FACH
state or CELL_DCH state from the idle mode
After releasing RRC connection, UE will switch to the idle
mode from the connected mode
The most important difference between idle mode and connected mode is whether UE has
RRC connection with UTRAN or not.
In idle mode, UE will be identified by IMSI, TMSI or PTMSI and so on.
In connected mode, UE will be identified by URNTI (UTRAN Radio Network Temporary
Identity), which is the ID of one RRC connection.
51

Random Access Procedure
Definition
Random access procedure is initiated by UE in order to get
service from the system. Meanwhile, the access channels are
allocated to the UE by system
This process may happen in the following scenarios:
Attach and detach
LA update and RA update
Signaling connection for services
52

Random Access Channel
AICH access
slots
10 ms
#0 #1 #2 #3 #14#13#12#11#10#9#8#7#6#5#4τp-a
#0 #1 #2 #3 #14#13#12#11#10#9#8#7#6#5#4
PRACH
access slots
SFN mod 2 = 0 SFN mod 2 = 1
10 ms
Access slot set 1 Access slot set 2
Definition
UE will transmit the preamble at the access time slot
Each 20ms access frame is composed of two 10ms radio frames, which is divided into 15
access time slot, and 5120 chips for each slot
The PRACH access slots, AICH access slots and their time offset are showed in the above
figure
53

RACH Sub-Channels
1413121110987
210765436
1413121110985
543210764
8141312111093
765432102
1110981413121
765432100
11109876543210
Random access sub-channels numberSFN
mod 8
The access slots of different RACH sub-channels are illustrated by
the following table
A RACH sub-channel defines a sub-set of the total set of uplink access slots. There are a total
of 12 RACH sub-channels.
54

Access Service Class
The PRACH resources can be classified into several ASCs,
so as to provide RACH applications with different priorities.
For Frequency Division Duplex (FDD) mode, the PRACH resources include access timeslots
and preamble signatures, which can be classified into several ASCs, so as to provide RACH
applications with different priorities.
The ASCs range from 0 to 7, and the quantity of ASCs is 8. "0" indicates the highest priority
and "7" indicates the lowest priority.
The system will assign random access sub-channels and signatures according to the ASC
(Access Service Class ) of UE.
Set ASC of PRACH through ADD PRACHASC, modify it through MOD PRACHASC, and
remove it through RMV PRACHASC.
55

Access Control
“Access Control” is used by network operators to prevent
overload of radio access channels under critical conditions.
Access class 0~Access Class 9
Access class 11~Access Class 15
Access class 10
The access class number is stored in the SIM/USIM.
Access class 0~9 are allocated to all the users. And the 10 classes show the same priority.
Access class 11~15 are allocated to specific high priority users as follows. (The enumeration is
not meant as a priority sequence):
Access class 15: PLMN staff
Access class 14: users subscribing to emergency services
Access class 13: public organizations
Access class 12: users subscribing to security services
Access class 11: users responsible for PLMN management
Access Class 10 indicates whether or not network access for Emergency Calls is allowed for
UEs with access classes 0 to 9 or without an IMSI. For UEs with access classes 11 to 15,
Emergency Calls are not allowed if both "Access class 10" and the relevant Access Class (11
to 15) are barred. Otherwise, Emergency Calls are allowed.
56

Mapping between AC and ASC
The AC-ASC mapping information is optional and used for
the System Information Block 5 (SIB5) only.
Set the mapping between AC and ASC through ADD PRACHACTOASCMAP, modify it
through MOD PRACHACTOASCMAP, and remove it through RMV PRACHACTOASCMAP.
57

START
Choose a RACH sub channel from
available ones
Get available signatures
Set Preamble Retrans Max
Set Preamble_Initial_Power
Send a preamble
Check the corresponding AI
Increase message part power by
p-m based on preamble power
Set physical status to be RACH
message transmitted Set physical status to be Nack
on AICH received
Choose a access slot again
Counter> 0 & Preamble
power-maximum allowed power
<6 dB
Choose a signature and
increase preamble transmit power
Set physical status to be Nack
on AICH received
Get negative AI
No AI
Report the physical status to MAC
END
Get positive AI
The counter of preamble retransmit
Subtract-1, Commanded preamble
power increased by Power Ramp Step
N
Y
Send the corresponding
message part
Random Access Procedure
58

Physical random access procedure
1. Derive the available uplink access slots, in the next full access slot set, for the set of
available RACH sub-channels within the given ASC. Randomly select one access slot
among the ones previously determined. If there is no access slot available in the
selected set, randomly select one uplink access slot corresponding to the set of
available RACH sub-channels within the given ASC from the next access slot set. The
random function shall be such that each of the allowed selections is chosen with equal
probability
2. Randomly select a signature from the set of available signatures within the given
ASC
3. Set the Preamble Retransmission Counter to Preamble_ Retrans_ Max
4. Set the parameter Commanded Preamble Power to Preamble_Initial_Power
5. Transmit a preamble using the selected uplink access slot, signature, and preamble
transmission power
6. If no positive or negative acquisition indicator (AI ≠ +1 nor –1) corresponding to the
selected signature is detected in the downlink access slot corresponding to the
selected uplink access slot:
A: Select the next available access slot in the set of available RACH sub-
channels within the given ASC
B: select a signature
C: Increase the Commanded Preamble Power
D: Decrease the Preamble Retransmission Counter by one. If the Preamble
Retransmission Counter > 0 then repeat from step 6. Otherwise exit the
physical random access procedure
7. If a negative acquisition indicator corresponding to the selected signature is
detected in the downlink access slot corresponding to the selected uplink access slot,
exit the physical random access procedure Signature
8. If a positive acquisition indicator corresponding to the selected signature is detected ,
Transmit the random access message three or four uplink access slots after the uplink
access slot of the last transmitted preamble
9. Exit the physical random access procedure
59

RRC Connection Message
Typical RRC connection messages
RRC_CONNECTION_REQUEST
RRC_CONNECTION_SETUP
RRC_CONNECTION_SETUP_COMPLETE
RRC_CONNECTION_RELEASE
When a UE needs network service, it first sets up RRC connection as follows:
The UE sends a RRC CONNECTION REQUEST message from the cell where it
camps to the RNC.
The RNC allocates related resources for the UE and sends an RRC CONNECTION
SETUP message to the UE.
The UE sends a RRC CONNECTION SETUP COMPLETE message to the RNC. The
RRC connection setup ends.
60

UE Timers and Constants in Idle Mode
T300
Parameter name: Timer 300 [ms]
Recommended value: D2000, namely 2000ms
N300
Parameter name: Constant 300
T300
Parameter name: Timer 300[ms]
Value range: D100, D200, D400, D600, D800, D1000, D1200, D1400, D1600, D1800,
D2000, D3000, D4000, D6000, D8000 .
Physical value range: 100, 200, 400, 600, 800, 1000, 1200, 1400, 1600, 1800, 2000,
3000, 4000, 6000, 8000
Physical unit: ms
Content: T300 is started after the UE transmits the RRC CONNECTION REQUEST
message and stopped after the UE receives the RRC CONNECTION SETUP
message. RRC CONNECTION REQUEST resents upon the expiry of the timer if V300
less than or equal to N300. Otherwise, the UE enters idle mode.
Recommended value: D2000.
Set this parameter through SET IDLEMODETIMER, query it through SET
IDLEMODETIMER.
N300
Value range: 0~7 .
Content: Maximum number of retransmission of RRC CONNECTION REQUEST .
IDLEMODETIMER.
61

UE Timers and Constants in Idle Mode
T312
Parameter name: Timer 312 [s]
Recommended value: 6, namely 6s
N312
Recommended value: D1, namely 1
T312
Parameter name: Timer 312[s]
Value range: 1~15 .
Physical value range: 1~15s
Physical unit: s
Content: T312 is started after the UE starts to establish a DCH and stopped when the
UE detects N312 consecutive "in sync" indications from L1. It indicates physical
channel setup failure upon the expiry of the timer.
IDLEMODETIMER.
N312
Value range: D1, D2, D4, D10, D20, D50, D100, D200, D400, D600, D800, D1000 .
Physical value range: 1, 2, 4, 10, 20, 50, 100, 200, 400, 600, 800, 1000
Content: Maximum number of consecutive "in sync" indications received from L1. .
Recommended value: D1.
IDLEMODETIMER.
62

RRC Connection Establish Channel
Type and Bit Rate
RRCCAUSE
Parameter name: Cause of RRC connection establishment
Recommended value: none
SIGCHTYPE
Parameter name: Channel type for RRC establishment
Recommended value: none
RRCCAUSE
Parameter name: Cause of RRC connection establishment
Value range: ORIGCONVCALLEST, ORIGSTREAMCALLEST, ORIGINTERCALLEST,
ORIGBKGCALLEST, ORIGSUBSTRAFFCALLEST, TERMCONVCALLEST,
TERMSTREAMCALLEST, TERMINTERCALLEST, TERMBKGCALLEST,
EMERGCALLEST, INTERRATCELLRESELEST, INTERRATCELLCHGORDEREST,
REGISTEST, DETACHEST, ORIGHIGHPRIORSIGEST, ORIGLOWPRIORSIGEST,
CALLREEST, TERMHIGHPRIORSIGEST, TERMLOWPRIORSIGEST,
TERMCAUSEUNKNOWN, DEFAULTEST.
Content: The cause of Rrc connection establishment. .
Recommended value: none.
Set this parameter through SET RRCESTCAUSE, query it through LST
RRCESTCAUSE.
SIGCHTYPE
Parameter name: Channel type for RRC establishment
Value range: FACH, DCH_3.4K_SIGNALLING, DCH_13.6K_SIGNALLING.
Content: FACH indicates that the RRC is established on the common channel.
DCH_3.4K_SIGNALLING indicates that the RRC is established on the dedicated
channel of 3.4 kbit/s. DCH_13.6K_SIGNALLING indicates that the RRC is established
on the dedicated channel of 13.6 kbit/s. .
Recommended value: none.
RRCESTCAUSE.
63

RRC Connection Establish Channel
Type and Bit Rate
INTRAMEASCTRL
Parameter name: IntraMeas Ctrl Ind for RRC establishment
Recommended value: SUPPORT
INTRAMEASCTRL
Parameter name: IntraMeas Ctrl Ind for RRC establishment
Value range: NOT_SUPPORT, SUPPORT.
Content: NOT_SUPPORT indicates that the Intrafreq measurement control message
will be send in RRC Connection Establishment. SUPPORT indicates that the Intrafreq
measurement control will not be send in RRC Connection Establishment.
Recommended value: SUPPORT .
RRCESTCAUSE.
64

www.huawei.com
WCDMA Power Control
and Relevant Parameters
263

Objectives
Upon completion of this course, you will be able to:
Describe the purpose and function of power control
Explain open loop power control and parameters
Explain inner loop power control and relevant parameters
Explain outer loop power control and relevant parameters
264

Contents
1. Power Control Overview
2. Open Loop Power Control
3. Closed Loop Power Control
265

Contents
266

Purpose of Uplink Power Control
Uplink Transmission Character
Self-interference system
Uplink capacity is limited by interference level
Near-far effect
Fading
Uplink Power Control Function
Ensure uplink quality with minimum transmission power
Decrease interference to other UE, and increase capacity
Solve the near-far effect
Save UE transmission power
CDMA system have the embedded characteristics of self-interference, for uplink one
user’s transmission power become interference to others.
The more connected users, the higher interference. Generally the capacity is limited by
interference level.
WCDMA suffer from Near-far effect, which means if all UE use the same transmission
power, the one close to the NodeB may block the entire cell.
Uplink power control can guarantee the service quality and minimize the required
transmission power. It will resolve the near-far effect and resist fading of signal
propagation. By lowering the uplink interference level, the system capacity will be
increased.
267

Purpose of Downlink Power Control
Downlink Transmission Character
Interference among different subscribers
Interference from other adjacent cells
Downlink capacity is limited by NodeB transmission power
Fading
Downlink Power Control Function
Ensure downlink quality with minimum transmission power
Decrease interference to other cells, and increase capacity
Save NodeB transmission power
The downlink has different characteristics from the uplink, for downlink interference is
caused by multi-path, part of one user’s power also become interference to others.
Downlink power from adjacent cells also is one part of interference to the own cell.
Transmission power of NodeB is shared by all users channels, so downlink capacity
usually is considered to be limited by transmission power.
Downlink power control also can guarantee the service quality and minimize the
required transmission power, so the capacity is maximized in case that interference is
lowered.
268

Effect of Power Control
Time (ms)
0 200 400 600 800
-20
-15
-10
-5
0
5
10
15
20
Relativepower(dB)
Channel Fading
Transmitting power
Receiving power
Because of channel fading in mobile communication system, the radio signal is
deteriorated and fluctuated, the fast power control become one key technology to resist
this phenomenon.
In this figure, the channel fading is compensated by the transmitting power, which is
adjusted by the fast power control, so the receiving power is almost constant and the
radio propagation condition is improved.
269

Power Control Classification
Open Loop Power Control
Uplink / Downlink Open Loop Power Control
Closed Loop Power Control
Uplink / Downlink Inner Loop Power Control
Uplink / Downlink Outer Loop Power Control
In WCDMA system, power control includes open loop and closed loop power control.
Open loop power control is used to determine the initial transmission power, and the
closed loop power control adjusts the transmission power dynamically and
continuously during the connection.
For uplink, the UE’s transmission power is adjusted; and for downlink, the NodeB’s
transmission power is adjusted.
270

Power Control For Physical Channels
Power control methods are adopted for these physical channels:
“√" – can be applied, “×" – not applied
√×××SCH
√×××PICH
√×××AICH
×××√PRACH
√×××SCCPCH
√×××PCCPCH
×√√√DPCCH
×√√√DPDCH
Outer Loop
Power Control
Inner Loop
Power Control
No Power
Control
Closed Loop Power ControlOpen Loop
Power
Control
Physical
Channel
Open loop power control is used in two cases:
1. to decide the initial transmission power of PRACH preamble.
2. to decide the initial transmission power of DPCCH / DPDCH.
Closed loop power control is only applied on DPCCH and DPDCH
For other common channels, power control is not applied, they will use fixed
transmission power:
The PCPICH power is defined by the PCPICH TRANSMIT POWER parameter
as an absolute value in dBm.
All other common channels power is defined in relation with the PCPICH
TRANSMIT POWER parameter, and measured in dB.
271

Common Physical Channel Power Parameters
MAXTXPOWER
Parameter name: Max transmit power of cell
The recommended value is 430, namely 43dBm
PCPICHPOWER
Parameter name: PCPICH transmit power
MAXTXPOWER
Parameter name: Max transmit power of cell
Value Range: 0 to 500
Physical Value Range: 0dBm to 50 dBm, step 0.1dB
Content: The sum of the maximum transmit power of all DL channels in a cell.
Set this parameter through ADD CELLSETUP, query it through LST CELL and modify it
through MOD CELL
PCPICHPOWER
Parameter name: PCPICH transmit power
Value Range: -100 to 500
Physical Value Range: -10dBm to 50 dBm, step 0.1dB
Content: This parameter should be set based on the actual environment and the
downlink coverage should be guaranteed firstly. If PCPICH transmit power is configured
too great, the cell capacity will be decreased, for power resources is occupied by
common channel and the interference to traffic channels is also increased.
Set this parameter through ADD PCPICH, query it through LST PCPICH and modify it
through MOD CELL
272

PSCHPOWER or SSCHPOWER
Parameter name: PSCH / SCCH transmit power
The recommended value is -50, namely -5dB
BCHPOWER
Parameter name: BCH transmit power
PSCHPOWER or SSCHPOWER
Parameter name: PSCH / SCCH transmit power
Value range: -350 to 150.
Physical value range: -35 to 15, step 0.1dB
Content: The offset between the PSCH / SSCH transmit power and PCPICH transmit
power.
For PSCH Power, set it through ADD PSCH, and query it through LST PSCH; for SSCH
Power, set it through ADD SSCH, and query it through LST SSCH. And modify it through
MOD CELL
BCHPOWER
Parameter name: BCH transmit power
Value Range：-350 to 150
Physical Value Range：-35 to 15 dB, step 0.1dB
Content: The offset between the BCH transmit power and PCPICH transmit power.
Set this parameter through ADD BCH, query it through LST BCH, and modify it through
MOD CELL
273

MAXFACHPOWER
Parameter name: Max transmit power of FACH
The recommended value is 10, namely 1dB
PCHPOWER
Parameter name: PCH transmit power
MAXFACHPOWER
Parameter name: Max transmit power of FACH
Value range : -350 to 150
Content: The offset between the FACH transmit power and PCPICH transmit
power.
Set this parameter through ADD FACH, query it through LST FACH, and modify
it through MOD SCCPCH
PCHPOWER
Parameter name: PCH transmit power
Content: The offset between the PCH transmit power and PCPICH transmit
power.
Set this parameter through ADD PCH, query it through LST PCH, and modify it
through MOD SCCPCH
274

AICHPOWEROFFSET
Parameter name: AICH power offset
The default value of this parameter is -6, namely -6dB
PICHPOWEROFFSET
Parameter name: PICH power offset
AICHPOWEROFFSET
Parameter name: AICH power offset
Value Range： -22 to 5
Physical Value Range： -22 to 5 dB, step 1dB
Content: The offset between the AICH transmit power and PCPICH transmit
power.
Set this parameter through ADD CHPWROFFSET, query it through LST
CHPWROFFSET, and modify it through MOD AICHPWROFFSET
PICHPOWEROFFSET
Parameter name: PICH power offset
Physical Value Range：-10 to 5 dB , step 1dB
Content: The offset between the PICH transmit power and PCPICH transmit
power.
Set this parameter through ADD CHPWROFFSET, query it through LST
CHPWROFFSET, and modify it through MOD PICHPWROFFSET
275

Contents
276

Contents
2.1 Open Loop Power Control Overview
2.2 PRACH Open Loop Power Control
2.3 Downlink Dedicated Channel Open Loop Power Control
2.4 Uplink Dedicated Channel Open Loop Power Control
277

Open Loop Power Control Overview
Purpose
Calculate the initial transmission power of uplink / downlink channels
Principle
Estimates the downlink signal power loss on propagation path
Path loss of the uplink channel is related to the downlink channel
Application
Open loop power control is applied only at the beginning of connection
setup to set the initial power value.
In downlink open loop power control, the initial transmission power is calculated
according to the downlink path loss between NodeB and UE.
In uplink, since the uplink and downlink frequencies of WCDMA are in the same
frequency band, a significant correlation exists between the average path loss of the
two links. This make it possible for each UE to calculate the initial transmission power
required in the uplink based on the downlink path loss.
However, there is 90MHz frequency interval between uplink and downlink frequencies,
the fading between the uplink and downlink is uncorrelated, so the open loop power
control is not absolutely accurate.
278

Contents
279

PRACH Open Loop Power Control
5. Downlink Synchronization
UE Node B
Serving
RNC
DCH - FP
Allocate RNTI
Select L1 and L2
parameters
RRCRRC
NBAPNBAP
3. Radio Link Setup Response
NBAPNBAP
2. Radio Link Setup Request
RRCRRC
7. CCCH: RRC Connection Set up
Start RX
description
Start TX
description
4. ALCAP Iub Data Transport Bearer Setup
RRCRRC
9. DCCH: RRC Connection Setup Complete
6. Uplink Synchronization
NBAPNBAP
8. Radio Link Restore Indication
DCH - FP
DCH - FP
DCH - FP
Open loop power
control of PRACH
1. CCCH: RRC Connection Request
In access procedure, the first signaling “RRC CONNECTION REQUEST” is
transmitted in message part on PRACH.
Before PRACH message part transmission, UE will transmit PRACH preamble, and
the transmission power of first preamble is calculated by this PRACH open loop power
control.
280

Initial Power Calculation for the First Preamble
When UE needs to set up a RRC connection, the initial power
of uplink PRACH can be calculated according to the following
formula:
PowerTxInitialgCalculatinForValueConstant+ceInterferenUL+
CPICH_RSCP-PowerTransmitPCPICH=ernitial_PowPreamble_I
In this formula, where
PCPICH TRANSMIT POWER defines the PCPICH transmit power in a cell. It is
broadcast in SIB5.
CPICH_RSCP means received signal code power, the received power
measured on the PCPICH. The measurement is performed by the UE.
UL interference is the UL RTWP measured by the NodeB. It is broadcast in SIB7.
CONSTANT VALUE compensates for the RACH processing gain. It is broadcast
in SIB5.
The initial value of PRACH power is set through open loop power control. UE operation
steps are as follows:
1. Read “Primary CPICH DL TX power”, “UL interference” and “Constant value”
from system information.
2. Measure the value of CPICH_RSCP;
3. Calculate the Preamble_Initial_Power of PRACH.
281

PRACH Open Loop Power Control Parameters
CONSTANTVALUE
Parameter name: Constant value for calculating initial TX
power
CONSTANTVALUE
Parameter name: Constant value for calculating initial TX power
Value range : -35 ~ -10
Physical Value Range：-35 to -10 dB
Content: It is used to calculate the transmit power of the first preamble in the
random access process.
Set this parameter through ADD PRACHBASIC, query it through LST PRACH,
and modify it through MOD PRACHUUPARAS
282

Timing relationship of PRACH and AICH
AICH
PRACH
1 access slot
τ p-a
τ p-mτp-p
Pre-
amble
Pre-
amble
Message
part
Acq.
Ind.
After UE transmit the first Preamble on PRACH, it will wait for the corresponding AI
(Acquisition Indicator) on the AICH. The timing relationship of PRACH and AICH is
shown in above figure.
There will be 3 parameters used to define the timing relationship:
τp-p: time interval between two PRACH preambles. τp-p is not a fixed value, it is
decided by selecting access slot of PRACH preambles,
Here τp-p has one restriction, it must be longer than a minimum value τp-p min ,
namely τp-p ≥ τp-p min.
τp-a: time interval between PRACH preamble and AICH Acquisition Indicator. If
UE sends the PRACH preamble, it will detect the responding AI after τp-a time.
τp-m: time interval between PRACH preamble and PRACH message part. If UE
sends the PRACH preamble and receives positive AI from the AICH, it will send
the message part after τp-m time.
283

AICHTXTIMING
Parameter name: AICH transmission timing
Content:
When AICHTXTIMING = 0,
τp-p,min = 15360 chips, τp-a = 7680 chips, τp-m = 15360 chips
The recommended value is 1
Parameter AICHTXTIMING is used to define the set of τp-p min, τp-a, τp-m.
AICHTXTIMING
Parameter name: AICH transmission timing
Value range：0,1
Content:
Set this parameter through ADD AICH, query it through LST AICH, and modify it
needs de-activated the cell through DEA CELL. After the old configuration of
AICH is deleted through RMV AICH , a new AICH can be established through
ADD AICH
284

Power Ramping for Preamble Retransmission
Power Ramp Step
Power Offset Pp-m
Preamble_Initial
_Power
Message
part
Pre-
amblePre-
amble
……
Pre-
amblePre-
amble
＃1 ＃3 ＃N＃2
After UE transmit the first Preamble,
If no positive or negative AI on AICH is received after τp-a time,
UE shall increase the preamble power by POWER RAMP STEP, and
retransmit the preamble.
This ramping process stops until the number of transmitted preambles has
reached the MAX PREAMBLE RETRANSMISSION within an access cycle,
or when the maximum number of access cycles has reached MAX
PREAMBLE LOOP.
If a negative AI on AICH is received by the UE after τp-a time,
which indicates rejection of the preamble, the UE shall wait for a certain
“Back-off Delay” and re-initiate a new random access process.
When a positive AI on AICH is received by UE after τp-a time,
it will transmit the random access message after the uplink access slot of
the last preamble.
The transmit power of the random access message control part should be
POWER OFFSET higher than the power of the last transmitted preamble.
285

POWERRAMPSTEP
Parameter name: Power increase step
PREAMBLERETRANSMAX
Parameter name: Max preamble retransmission
The Recommended value is 20
POWERRAMPSTEP
Parameter name: Power increase step
Value range : 1 to 8
Physical Value Range: 1 to 8 dB
Content: The power increase step of the random access preambles transmitted
before the UE receives the acquisition indicator in the random access process.
PREAMBLERETRANSMAX
Parameter name: Max preamble retransmission
Content: The maximum number of preambles transmitted in a preamble ramping
cycle.
286

MMAX
Parameter name: Max preamble loop
The recommended value is 8
NB01MIN / NB01MAX
Parameter name: Random back-off lower / upper limit
The recommended value: 0 for both NB01MIN / NB01MAX
MMAX
Parameter name: Max preamble loop
Value range: 1 to 32
Content: The maximum number of random access preamble loops.
Set this parameter through ADD RACH, query it through LST RACH, and modify
it first de-activated the cell through DEA CELL, then MOD RACH.
NB01MIN / NB01MAX
Parameter name: Random back-off lower / upper limit
Value range: 0 to 50
Content: The lower / upper limit of random access back-off delay.
The recommended value: 0 for both NB01MIN / NB01MAX
Set this parameter through ADD RACH, query it through LST RACH, and modify
it first de-activated the cell through DEA CELL, then MOD RACH.
287

POWEROFFSETPPM
Parameter name: Power offset
The default value:
-3dB for signalling transmission;
-2dB for service transmission.
POWEROFFSETPPM
Parameter name: Power offset
Value range: -5 to 10dB
Content: The power offset between the last access preamble and the message
control part. The power of the message control part can be obtained by adding
the offset to the access preamble power.
The recommended value of this parameter is -3dB for signalling transmission ,
and that -2dB for service transmission
Set this parameter through ADD PRACHTFC, query it through LST PRACH, and
modify it de-activated the cell through DEA CELL . After the old configuration of
PRACH is deleted through RMV PRACHTFC , a new parameters can be
established through ADD PRACHTFC
The PRACH message also consists of control part and data part, here the POWER
OFFSET is the difference between the PRACH preamble and the message control part.
The PRACH message uses GAIN FACTOR to set the power of control / data part:
GAIN FACTOR BETAC ( βc ) is the gain factor for the control part.
GAIN FACTOR BETAD ( βd ) is the gain factor for the data part.
288

Contents
289

DL DPDCH Open Loop Power Control
UE Node B
Serving
RNC
DCH - FP
Allocate RNTI
Select L1 and L2
parameters
RRCRRC
NBAPNBAP
NBAPNBAP
RRCRRC
Start RX
description
Start TX
description
RRCRRC
NBAPNBAP
DCH - FP
DCH - FP
DCH - FP
DL DPDCH Open
Loop Power Control
According to the RRC connection establishment procedure, after RNC received the
“RRC CONNECTION REQUEST” message, and NodeB set up the radio link for UE,
then Iub interface resources is established between NodeB and RNC.
When DCH-FP of Iub interface finished downlink and uplink synchronization, the
downlink DPCH starts to transmit, and DPDCH initial transmission power is calculated
through open loop power control.
290

When a dedicated channel is set up, the initial power of
downlink DPDCH can be calculated according to the
following formula:
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
−××= Total
CPICH
CPICH
DLInitial P
)No/Ec(
P
)
No
Eb
(
W
R
P α
In this formula, where
R is the requested data bitrate by the user
W is the chip rate
(Eb/No)DL is the Eb/No target to ensure the service quality. RNC searches for
the (Eb/No)DL dynamically in a set of pre-defined values according to specific cell
environment type, coding type, bitrate, BLER target and etc.
(Ec/Io)CPICH is the CPICH signal quality measured by UE, then it is sent to RNC
through RACH.
α is the orthogonality factor in the downlink. In Huawei implementation, α is set
to 0.
Ptotal is the total carrier transmit power measured at the NodeB
The initial transmission power of downlink DPDCH could be calculated through this
formula, then, initial transmission power of downlink DPCCH can be obtained
according to the power offset: PO1, PO2 and PO3.
291

Data1 TPC TFCI Data2 Pilot
Downlink
Transmit
Power
DPCCHDPDCH DPDCH DPCCH
PO2
PO1
PO3
1 timeslot
This figure shows the power offset of downlink DPCH :
PO1 is the power offset of DPCCH TFCI bits to DPDCH data bits.
PO2 is the power offset of DPCCH TPC bits to DPDCH data bits.
PO3 is the power offset of DPCCH Pilot bits to DPDCH data bits.
The values of PO1, PO2 and PO3 are configured on RNC.
292

DL DPDCH Open Loop Power Control Parameter
TFCIPO
Parameter name: TFCI power offset
TPCPO
Parameter name: TPC power offset
TFCIPO
Parameter name: TFCI power offset
Physical value range: 0 to 6 dB, step: 0.25
Content: The offset of TFCI bit transmit power from data bit transmit power in
each time slot of radio frames on DL DPCH
Set this parameter through SET FRC, query it through LST FRC, and modify it
through SET FRC
TPCPO
Parameter name: TPC power offset
Content: The offset of TPC bit transmit power from data bit transmit power in
through SET FRC
293

DL DPDCH Open Loop Power Control Parameter
PILOTPO
Parameter name: Pilot power offset
PILOTPO
Parameter name: Pilot power offset
Content: The offset of pilot bit transmit power from data bit transmit power in
through SET FRC
294

Downlink Power Control Restriction
The power of downlink dedicated channel is limited by an
upper and lower limit for each radio link.
The DL DPDCH power could not exceed Maximum_DL_Power,
nor could it be below Minimum_DL_Power.
RLMAXDLPWR / RLMINDLPWR
Parameter name: RL Max / Min DL TX power
The recommended value is shown in the following table.
Note: Both downlink open loop and close loop power control will be limited by this parameter.
RLMAXDLPWR
Parameter name: RL Max DL TX power
Content: The maximum downlink transmit power of radio link. This parameter should
fulfill the coverage requirement of the network planning, and the value is relative to
[PCPICH transmit power]
Set this parameter through ADD CELLRLPWR , query it through LST CELLRLPWR, and
modify it through MOD CELLRLPWR
RLMINDLPWR
Parameter name: RL Min DL TX power
Content: The minimum downlink transmit power of radio link. This parameter should
consider the maximum downlink transmit power and the dynamic range of power control,
and the value is relative to [PCPICH transmit power].
Since the dynamic range of power control is set as 15dB, this parameter is
recommended as [RL Max DL TX power] – 15 dB.
Set this parameter through ADD CELLRLPWR, query it through LST CELLRLPWR, and
modify it through MOD CELLRLPWR
295

Downlink Power Restriction Parameters
Referential configurations for typical services:
8-114384 kbps
8-132256 kbps
16-150144 kbps
32-17-264 kbps
64-19-432 kbps
128-23-88 kbps
PS Domain
32-15064 kbps
32-15056 kbps
64-17-232 kbps
64-17-228 kbps
128-18-312.2 kbps AMR
CS Domain
Downlink SF
RL Min Downlink
Transmit Power
RL Max Downlink
Transmit Power
Service
296

Contents
297

UL DPCCH Open Loop Power Control
UE Node B
Serving
RNC
DCH - FP
Allocate RNTI
Select L1 and L2
parameters
RRCRRC
NBAPNBAP
NBAPNBAP
RRCRRC
Start RX
description
Start TX
description
RRCRRC
NBAPNBAP
DCH - FP
DCH - FP
DCH - FP
Open Loop Power
Control of UL DPCCH
According to the RRC connection establishment procedure, after RNC sent the “RRC
CONNECTION SETUP” message, UE will try to synchronize with NodeB, and the
uplink DPCCH starts to transmit, here DPCCH initial transmission power is calculated
through open loop power control
298

UL DPCCH Open Loop Power Control
The initial power of the uplink DPCCH can be calculated
according to the following formula:
Where
CPICH_RSCP means the received signal code power, the received
power measured on the CPICH.
DPCCH_Power_Offset is provided by RNC to the UE via RRC
signaling.
RSCP_CPICHOffset_Power_DPCCHPower_Initial_DPCCH −=
For Huawei, DPCCH_Power_Offset is calculated with the following formula:
Where
PCPICH Transmit Power defines the PCPICH transmit power in a cell.
UL Interference is the UL RTWP measured by the NodeB.
Default Constant Value reflects the target Ec/No of the uplink DPCCH
preamble.
ValuettanConsDefault
ceInterferenULPowerTransmitPCPICHOffset_Power_DPCCH
+
+=
299

UL DPCCH Open Loop Power Control Parameter
DEFAULTCONSTANTVALUE
Parameter name: Constant value configured by default
The recommended value is -27, namely -27dB.
DEFAULTCONSTANTVALUE
Parameter name: Constant value configured by default
Value range : -35 to -10 , unit :dB
Content: This parameter is used to obtain DPCCH_Power_Offset, which is used
by UE to calculate the initial transmit power of UL DPCCH during the open loop
power control process.
through SET FRC
300

Uplink Power Control Restriction
During the operation of uplink power control, the UE
transmit power shall not exceed the Maximum Allowed
Uplink Transmit Power.
MAXALLOWEDULTXPOWER
The recommended value is 21, namely 21 dBm.
MAXALLOWEDULTXPOWER
Value range: -50 to 33
Physical value range: -50 to 33 dBm. Step: 1
Content: The maximum allowed uplink transmit power of a UE in the cell, which
is related to the network planning.
CELLSELRESEL, and modify it through MOD CELLSELRESEL
301

Uplink Power Control Restriction
In addition, there are four parameters which correspond to the maximum
allowed transmit power of four classes of services respectively:
MAXULTXPOWERFORCONV
Parameter name: Max UL TX power of Conversational service
MAXULTXPOWERFORSTR
Parameter name: Max UL TX power of Streaming service
MAXULTXPOWERFORINT
Parameter name: Max UL TX power of Interactive service
MAXULTXPOWERFORBAC
Parameter name: Max UL TX power of Background service
The recommended value is 24, namely 24 dBm.
MAXULTXPOWERFORCONV
Parameter name: Max UL TX power of Conversational service
MAXULTXPOWERFORSTR
Parameter name: Max UL TX power of Streaming service
MAXULTXPOWERFORINT
Parameter name: Max UL TX power of Interactive service
MAXULTXPOWERFORBAC
Parameter name: Max UL TX power of Background service
Value range: -50 to 33
Physical value range: -50 to 33 dBm. Step: 1
Content: The maximum UL transmit power for specific service in the cell, which
is related to the network planning.
Set this parameter through ADD CELLCAC, query it through LST CELLCAC,
and modify it through MOD CELLCAC
302

Contents
303

Contents
3.1 Closed Loop Power Control Overview
3.2 Uplink Inner Loop Power Control
3.3 Downlink Inner Loop Power Control
3.4 Outer Loop Power Control
304

Closed Loop Power Control Overview
Why closed loop power control is needed?
Open loop power control is not accurate enough, it can only
estimate the initial transmission power.
Closed loop power control can guarantee the QoS with
minimum power. By decreasing the interference, the system
capacity will be increased.
Inner LoopOuter Loop
SIRtar
SIRmea>SIRtar→ TPC=0
SIRmea<SIRtar→ TPC=1
Until
SIRmea=SIRtar
TPC
BLERtar
BLERmea>BLERtar→SIRtar
BLERmea<BLERtar→SIRtar
Until
BLERmea=BLERtar
TPC=1 Power
TPC=0 Power
Inner Loop Power Control
The receiver compares SIRmea (measured SIR) with SIRtar (target SIR), and decide the TPC to
send.
If SIRmea is greater than SIRtar, the TPC is set as “0” to increase transmission power
If SIRmea is less than SIRtar, the TPC is set as “1” to decrease transmission power
TPC is sent to the transmitter in DPCCH, the transmitter will adjust the power according to the
value of received TPC.
Through inner loop power control, the SIRmea can be ensured to approach SIRtar.
Outer Loop Power Control
The receiver compares BLERmea (measured BLER) with BLERtar (target BLER), and decide how
to set the SIRtar.
If BLERmea is greater than BLERtar, the SIRtar is increased
If BLERmea is less than BLERtar, the SIRtar is decreased
The adjusted SIRtar is sent for the inner loop power control, then it will be used in previous
process to guide the transmitter power adjustment.
Through outer loop power control, the BLERmea can be ensured to approach BLERtar.
305

Contents
306

Uplink Inner Loop Power Control
NodeB compares the measured SIR to the preset target SIR, then derives
TPC and sends the TPC Decision to UE.
TPC Decision
( 0, 1 )
Generate TPC_cmd
( -1, 0, 1 )
Adjust DPCCH Tx
△DPCCH =△TPC×TPC_cmd
Single RL / Soft HO
PCA1 / PCA2
Adjust DPDCH Tx
( βc , βd )
NodeB UE
Transmit TPC
Inner Loop
Set SIRtar
Compare SIRmea with SIRtar
SIRmea > SIRtar → TPC = 0
SIRmea ≤ SIRtar → TPC = 1
RNC sends SIRtar (target SIR) to NodeB and then NodeB compares SIRmea (measured
SIR) with SIRtar once every timeslot.
If the estimated SIR is greater than the target SIR, NodeB sends TPC “0” to UE
on downlink DPCCH TPC field.
Otherwise, NodeB sends TPC “1” to UE.
After reception of one or more TPC in a slot, UE shall derive a single TPC_cmd (TPC
command, with value among -1,0,1):
For UE is in soft handover state, more than one TPC is received in a slot, so
firstly multiple TPC_cmd is combined.
Two algorithms could be used by the UE for deriving the TPC_cmd, those are
PCA1 and PCA2 (PCA means Power Control Algorithm).
When deriving the combined TPC_cmd, UE shall adjust the transmit power of uplink
DPCCH with a step “UL Closed Loop Power Control Step Size“, as following:
△DPCCH =△TPC×TPC_cmd
This adjustment is executed on the DPCCH, then associated DPDCH transmit power
is calculated according to DPDCH / DPCCH power ratio βd / βc.
307

Uplink Inner Loop PCA1 with Single Radio Link
For single radio link and PCA1, UE derives one TPC_cmd in each
time slot as follows:
0110110110…… ……
…… ……TPC_cmd
TPC
-111-111-111-1
This control is performed in each time slot, so
the power control frequency is 1500Hz
When UE has single radio link, only one TPC will be received in each slot. In this case,
the value of TPC_cmd shall be derived by PCA1 as follows:
If the received TPC is equal to 0, then TPC_cmd for that slot is –1.
If the received TPC is equal to 1, then TPC_cmd for that slot is 1.
According to DPCCH channel structure, there are 15 time slots in a 10ms radio frame,
and the control is performed once in each time slot, so the frequency of uplink inner
loop PCA1 is 1500Hz.
308

Uplink Inner Loop PCA2 with Single Radio Link
For single radio link and PCA2, UE derives one TPC_cmd in each
5-slot group as follows:
This control is performed in each 5-slot group,
so the power control frequency is 300Hz
110111111100000
TS14TS13TS12TS11TS10TS9TS8TS7TS6TS5TS4TS3TS2TS1TS0
10ms radio frame
Group 2Group 1 Group 3
…… ……
0000010000-10000
TPC
TPC_cmd
…… ……
When UE has single radio link, only one TPC will be received in each slot. In this case,
the value of TPC_cmd shall be derived by PCA2 as follows:
For the first 4 slots of a set, TPC_cmd = 0.
For the fifth slot of a set, UE make the decisions on as follows:
If all 5 TPC within a group are 1, then TPC_cmd = 1 in the 5th slot.
If all 5 TPC within a group are 0, then TPC_cmd = -1 in the 5th slot.
Otherwise, TPC_cmd = 0 in the 5th slot.
According to DPCCH channel structure, there are 15 time slots in a 10ms radio frame,
and the control is performed once in each 5-slot group, so the frequency of uplink inner
loop PCA2 is 500Hz.
309

Uplink Inner Loop with Soft Handover
When UE enters soft handover state, on the NodeB side,
there are two phases :
Uplink synchronization phase
Multi-radio link phase
On UE side, UE will receive different TPCs from different
RLS in one time slot. Therefore, the UE should combine all
the TPCs to get a unique TPC_CMD.
On the NodeB side, there are two phases during the soft handover state:
Uplink synchronization phase
The NodeB should send durative “TPC = 1” to the newly-added RL before
successful synchronization.
Multi-radio link phase
Each NodeB and each cell will estimate the SIR individually and the general
TPC individually. Therefore, the UE may receive different TPC from different
RLS.
Especially, when UE is in softer handover state, it means UE has radio links to the
same NodeB, in this case, these RLs (Radio Link) belong to the same RLS (Radio Link
Set), and the all TPCs are the same from each RL.
310

Uplink Inner Loop PCA1 with Soft Handover
For each slot, combine TPC from
the same RLS, then get Wi
CELL1 CELL2
CELL4CELL3
RL1-1 RL1-2
RLS1
RLS2 RLS3Get TPC_cmd based on
TPC_cmd = γ (W1, W2, … WN)
0110110110…… ……RLS1-TPC (W1)
…… ……RLS2-TPC (W2) 1010101101
…… ……
…… ……TPC_cmd
1101100100
-1-1-1-11-1-11-1-1
RLS3-TPC (W3)
When UE is in soft handover state, multiple TPC will be received in each slot from
different cells in the active set. UE will generate the TPC_cmd by PCA1 as follows:
1. Combine the TPC from the same RLS and derive the Wi
When the RLs (Radio Link) are in the same RLS (Radio Link Set), they will
transmit the same TPC in a slot. In this case, the TPCs from the same RLS shall
be combined into one.
After combination, UE will obtain a soft symbol decision Wi for each RLSi.
2. Combine the TPC from different RLSs and derive the TPC_cmd
UE derives TPC_cmd, it is based on a function γ and all the N soft symbol
decisions Wi:
TPC_cmd = γ (W1, W2, … WN),
Where TPC_cmd can only take the values 1 or -1.
In Huawei implementation, the function γ shall fulfil the following criteria:
If the TPCs from all RLSs are “1”, the output of γ shall be equal to “1” ;
If one TPC from any RLS is “0”, the output of γ shall be equal to “-1”.
311

Combine TPC from same RLS
in each time slot
Calculate TPC_cmd
If any TPC_tempi = -1, TPC_cmd = -1
If , TPC_cmd = 1
Otherwise, TPC_cmd = 0
Calculate TPC_tempi for each RLSi
5.0_
1
1
>∑=
N
i
itempTPC
N
CELL1 CELL2
CELL4CELL3
RL1-1 RL1-2
RLS1
RLS2 RLS3
When UE is in soft handover state, multiple TPC will be received in each slot from
different cells in the active set. UE will generate the TPC_cmd by PCA2 as follows:
1. Combine the TPC from the same RLS.
When the RLs are in the same RLS, they will transmit the same TPC in a slot. In
this case, the TPCs from the same RLS shall be combined into one.
2. Calculate the TPC_tempi for each RLS
UE derives TPC_tempi through the same way in the last slide, as follows:
For the first 4 slots of a group, TPC_tempi = 0.
For the 5th slot of a group:
If all 5 TPCs within a group are 1, then TPC_tempi = 1 in the 5th slot.
If all 5 TPCs within a group are 0, then TPC_tempi = -1 in the 5th slot.
Otherwise, TPC_tempi = 0 in the 5th slot.
3. Calculate the TPC_cmd
UE derives TPC_cmd through the following criteria:
If any TPC_tempi is equal to -1, TPC_cmd is set to -1.
If , TPC_cmd = 1
Otherwise, TPC_cmd = 0
5.0temp_TPC
N
1 N
1i
i >∑=
312

RLS3
RLS2
RLS1 100100000000100
100110000011111
111110000011111
…… ……
10ms/frame
Group 1 Group 2 Group 3
RLS3
RLS2
RLS1 00000-1000000000
00000-1000010000
10000-1000010000
…… ……
TPC
TPC_tempi
00000-1000010000
…… ……
TPC_cmd
The example of the uplink inner loop PCA2 in soft handover state.
313

Uplink Inner Loop Power Control Parameters
PWRCTRLALG
Parameter name: Power control algorithm selection
The recommended value is ALGORITHM1
ULTPCSTEPSIZE
Parameter name: UL closed loop power control step size
PWRCTRLALG
Parameter name: Power control algorithm selection
Value range: ALGORITHM1, ALGORITHM2
Content: This parameter is used to inform the UE of the method for translating
the received TPC commands.
Recommended value: ALGORITHM1
through SET FRC
ULTPCSTEPSIZE
Parameter name: UL closed loop power control step size
Value range :1dB, 2dB
Content: The step size of the closed loop power control performed on UL
DPDCH. This parameter is mandatory when the parameter “Power control
algorithm selection” is set as "ALGORITHM1".
through SET FRC
314

Contents
315

Downlink Inner Loop Power Control
UE L1 compares the measured SIR to the preset target SIR, then derives
TPC and sends the TPC Decision to NodeB.
Derive TPCest(k)
( 0, 1 )
Generate PTPC(k)
Calculate P(k)
Adjust DPCH Tx Power
DPC_MODE
NodeB
L3 Set SIRtar
Derive and transmit
TPC based on
DPC_MODE
Inner Loop
UE
L1 compare
SIRmea with
SIRtar
Basically the downlink inner loop power control process is similar with uplink, UE L3
sends SIRtar to UE L1 and then UE L1 compares SIRmea with SIRtar :
If the SIRmea is greater than the SIRtar , UE sends TPC “0” to NodeB on uplink
DPCCH TPC field.
Otherwise, UE sends TPC “1” to NodeB.
The UE shall check the downlink power control mode before generating the TPC, two
algorithm DPC_MODE1 and DPC_MODE2 could be used by UE to derive the TPC.
Upon receiving the TPC, NodeB shall estimate the transmitted TPC and adjust its
downlink DPCCH/DPDCH power accordingly.
After reception of one or more TPC in a slot, NodeB shall derive the estimated TPC
TPCest(k) and calculate a PTPC(k), the power adjustment of k:th slot.
Then NodeB shall adjust the current downlink power P(k-1) to a new power P(k), and
adjust the power of the DPCCH and DPDCH with the same amount, since power
difference between them is fixed.
316

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