One of the aims of the CDMA1X system is to maximize the number of its users. If each mobile station (MS) adjusts its transmitter power to minimize the signal noise received by the base transceiver station (BTS), the capacity of the system is maximized. Higher power brings higher interference and results in more capacity loss. Power control can adjust the transmission power of the MS and BTS, aiming to minimize the interference After learning this course, you will learn the following： The importance of the power control of the CDMA system Categories and calculating theories of the power control Data configuration of the power control Chapter 1 Goals and Principles of Power Control Chapter 2 Categories and Arithmetic of Power Control Chapter 3 Data Configuration of Power Control Each couple of customers is in a same room. Each couple of customers speaks a language different from that spoken by other couples. If the noise becomes louder, all the customers will raise their voices. If the noise is too louder, the customers may go to other rooms. The customer who speaks too loudly will affect the communication of others. The transmission power of the control BTS and MS must ensure that the signal sent to the receiver through the complicated radio space can meet the threshold of correct demodulation. When the first principle is satisfied, the transmission power of the BTS and MS is required to be lowered as much as possible to decrease the interference between users and best optimize the network performance. The transmission power of the MS near the BTS is lower than that of the MS far from the BTS and of the MS in the fading areas.

1. Introduction to Power
Control of RG000003
CDMA 1X
ISSUE 2.1

2. One of the aims of the CDMA1X system is
to maximize the number of its users. If each
mobile station (MS) adjusts its transmitter
power to minimize the signal noise received
by the base transceiver station (BTS), the
capacity of the system is maximized. Higher
power brings higher interference and results
in more capacity loss. Power control can
adjust the transmission power of the MS
and BTS, aiming to minimize the
interference.
Preface

3. GoalsGoals
After learning this course, you will learn the
following ：
 The importance of the power control of the
CDMA system
 Categories and calculating theories of the
power control
 Data configuration of the power control

4. Chapter 1 Goals and Principles of Power ControlChapter 1 Goals and Principles of Power Control
Chapter 2 Categories and Arithmetic of Power Control
Chapter 3 Data Configuration of Power Control
Contents

5. Goals and Principles of Power ControlGoals and Principles of Power Control
CDMA Concept: cocktail loungeCDMA Concept: cocktail lounge  Each couple of customers is
in a same room.
 Each couple of customers
speaks a language different
from that spoken by other
couples.
 If the noise becomes louder,
all the customers will raise
their voices.
 If the noise is too louder, the
customers may go to other
rooms.
 The customer who speaks too
loudly will affect the
communication of others.

6. Goals and Principles of Power ControlGoals and Principles of Power Control
Gains from the Cocktail LoungeGains from the Cocktail Lounge
 The ground noise in current environment must be low enough.
That is, the working frequency band of the system is not
interfered.
 The power control is very important in the CDMA system.
The transmission power of the MS near the BTS is relatively
low and is high for the MS far from the BTS. All the MS
should transmit signals with as low power as possible, for the
transmission power of an MS is the noise for other MS.
 In the cocktail, each couple of customers speaks different
language, which is like that using different codes to
distinguish users.

7. Goals and Principles of Power ControlGoals and Principles of Power Control
 The transmission power of the control BTS
and MS must ensure that the signal sent to the
receiver through the complicated radio space
can meet the threshold of correct
demodulation.
 When the first principle is satisfied, the
transmission power of the BTS and MS is
required to be lowered as much as possible to
decrease the interference between users and
best optimize the network performance.
 The transmission power of the MS near the
BTS is lower than that of the MS far from the
BTS and of the MS in the fading areas.
Basic PrinciplesBasic Principles

8. QuestionsQuestions
 What are the goals of the power control?
 What are the principles of the power control?

9. Chapter 1 Goals and Principles of Power Control
Chapter 2 Categories and Arithmetic of Power ControlChapter 2 Categories and Arithmetic of Power Control
Chapter 3 Data Configuration of Power Control
Contents

10. Chapter 2 Categories and Arithmetic of Power ControlChapter 2 Categories and Arithmetic of Power Control
Section 1 Categories of Power Control
Section 2 Arithmetic of Reverse Power Control
Section 3 Arithmetic of Forward Power Control
Contents

11. Categories of Power Control
Based on the direction, we have:
Reverse power control
Forward power control
The previous two kinds of power control are
divided into the following respectively ：
Reverse power control
Reverse open loop power control
Reverse closed loop power control
Forward power control
Power control based on the measurement
report
EIB power control
Forward quick power control

12. Chapter 2 Categories and Arithmetic of Power ControlChapter 2 Categories and Arithmetic of Power Control
Section 1 Categories of Power Control
Section 2 Arithmetic of Reverse Power ControlSection 2 Arithmetic of Reverse Power Control
Section 3 Arithmetic of Forward Power Control
Contents

13. Arithmetic of Power ControlArithmetic of Power Control
Reverse Power Control
 The reverse power control is for the MS. The major aim is to
ensure that the signals received by the BTS receiver can reach the
minimize required Eb/Nt value through the adjustment of the
transmission power of the MS.
 Compared with the forward power control, the requirements for
the reverse power control is higher and the process is more
complicated:
 Eb/Nt=bit energy/effective noise power spectral density
 Ec/Io=chip energy/carrier frequency total power spectral
density

14. Arithmetic of Power ControlArithmetic of Power Control
Theories of Reverse Open Loop Power ControlTheories of Reverse Open Loop Power Control
 The reverse open loop power control bases on the hypothesis that the loss
of the forward link and the reverse link is similar.
 Based on this hypothesis, the MS estimates the forward link loss
according to the total received power and then estimates the transmission
power of the MS.
Transmission power of the MS
Forward link loss (dB)||
Reverse link loss (dB)
Transmission power
of the BTS
Receipt power of the BTS
Demodulation of the
BTS
Reverse link loss (dB)=Transmission power of the BTS (dBm)-Receipt
power of the MS (dBm)

15. Arithmetic of Power ControlArithmetic of Power Control
Theories of Reverse Open Loop Power ControlTheories of Reverse Open Loop Power Control
Tx_power = － MeanRx_Power + offsetpower + NOM_PWR –
16* NOM_PWR_EXTs + INIT_PWR+ interference correction
Ⅰ
Ⅲ
Ⅱ
Ⅰ ：
Ⅱ ：
Ⅲ ：
Tx_power= Ⅰ + PWR_STEP
Tx_power= Ⅱ + PWR_STEP
ACH
FCH ( 95 ) or PICH ( 2000 )
Imported to
Ⅳ
FCH ( 2000 )
Ⅳ ：
Ⅴ ：
Tx_power= Ⅲ + RLGAIN_ADJs
Tx_power = Ⅳ + RLGAIN_TRAFFIC_PILOT+OTHER1
The offset power is a constant defined in the protocol and related to Band
Class.RC and so on.
V

16. Arithmetic of Power ControlArithmetic of Power Control
 The reverse power is estimated based on
the transmission amount of the forward
link, but high error will occur due to the
irrelevance of forward and reverse links.
 The received power is affected by
neighbor BTSs and thus the high error
occurs at the edge of the district.
 The open loop power is the estimated
value that is not precise enough and needs
the closed loop to rectify the value.
Disadvantages of Reverse Open Loop Power ControlDisadvantages of Reverse Open Loop Power Control

17. Arithmetic of Power ControlArithmetic of Power Control
Reverse Closed Loop Power ControlReverse Closed Loop Power Control
The closed loop rectification indicates that based on the
estimation of the open loop, the MS can quickly rectify its
transmission power (800 times per second) according to
power control instruction received in the forward channel.
The closed loop verification is divided into:
inner loop
outer loop
After the closed loop power
control takes effect, the
transmission power of the MS
is obtained based on reverse
open loop estimation and
closed loop adjustment.

18. Arithmetic of Power ControlArithmetic of Power Control
 Outer loop ： The BSC obtains the set
value of the Eb/Nt based on the current
FER
 Inner loop ： The BTS fills the power bit in
the traffic frame based on the current
reverse Eb/Nt
 The reverse power control bits are sent
through the forward service channel.
Reverse Closed Loop Power ControlReverse Closed Loop Power Control

19. Arithmetic of Power ControlArithmetic of Power Control
BTS
Channel Assnmt. Msg.
Origination Msg
Base Sta. Acknlgmt. Order
TFC frames of 000s
TFC preamble of 000s
Base Sta. Acknlgmt. Order
Mobile Sta. Ackngmt. Order
Service Connect Msg.
Svc. Connect Complete Msg
Base Sta. Acknlgmt. Order
Call is Established!
MS
Probing
ACCESS
PAGING
FW TFC
PAGING
RV TFC
FW FC
RV TFC
FW TFC
RV TFC
FW TFC
Successful Access Attempt
Start point of the open loop
power control
Start point of the closed loop
power control 

20. Chapter 2 Categories and Arithmetic of Power ControlChapter 2 Categories and Arithmetic of Power Control
Section 1 Categories of Power Control
Section 2 Arithmetic of Reverse Power Control
Section 3 Arithmetic of Forward Power ControlSection 3 Arithmetic of Forward Power Control
Contents

21. Arithmetic of Forward Power ControlArithmetic of Forward Power Control
 The power of the forward CDMA channel is shared by the pilot
frequency, synchronization, paging and service channels.
 The intensity of the signal varies with the changes of distance
from the MS to the BTS. As the result, it is better to control the
power distribution for each traffic channel.
 The standard specifies that the MS must monitor the quality of
the forward traffic channel. After receiving the instructions from
the BTS, the MS sends the messages to the MS. The closed loop
process is similar with the reverse power control.
Features of Forward Power ControlFeatures of Forward Power Control

22. Arithmetic of Forward Power ControlArithmetic of Forward Power Control
 The forward power control is used for
the BTS
 Forward power control based on
the measurement report
 EIB Power control
 Forward quick power control
Categories of the Forward Power ControlCategories of the Forward Power Control

23.  You can collect statistics on forward channel quality in the following
modes based on the system setting.
 Threshold mode: When the number of the frame errors reaches the
threshold set by the system, the MS reports the PMRM message to
the BTS. In this way, the signals are decreased and the efficiency
improved.
 Cycle mode: When the number of the frames reaches the cycle
frames set by the system, the MS reports the PMRM messages to
the BTS.
 The MS can support the two modes at the same time. For sake of
convenient processing, the system does not support two modes at the
same time at present.
Arithmetic of Forward Power ControlArithmetic of Forward Power Control
Forward Power Control Based on Measurement ReportForward Power Control Based on Measurement Report

24. The BSC can adjust the forward channel based on the EIB in the reverse
service channel frame (reverse link frame) reported by the MS. The
EIB indicates erasure indicator bit and is used to judge the good and
bad frames.
Note:
From the version3 of the protocol on, the reverse traffic channel frames of
RateSet2 contains the EIB.
EBI setting: When it is set to 0, it indicates that the frame is good and has
passed the CRC verification of the physical layer; if it is set to 1, it
indicates that the frame is bad and has not passed the CRC verification.
Arithmetic of Forward Power ControlArithmetic of Forward Power Control
Theories of EIB Forward Power ControlTheories of EIB Forward Power Control

25.  Speed of calculating the EIB power control: 1 bit per 1 frame, that
is, 50 times/second.
 The good/bad frame is monitored on the F-FCH, the Arithmetic
delay of the EIB power control is 2 frame in general.
 To ensure the processing delay of different MSs, the EIB power
control is put in the first bit of the reverse service frame.
Arithmetic of Forward Power ControlArithmetic of Forward Power Control
Theories of EIB Forward Power ControlTheories of EIB Forward Power Control
i-1 i i+1 i+2
Received
Frames on
Forward
Fundamental or
Dedicated Control
Channel
20 ms
i-1 i i+1 i+2Reverse Power
Control
Subchannel
20 ms
Power control bits set to '1' for
bad frame(s) or '0' for good frame(s)
i+2

26. Frame Quality Counter Power Adjustment
Good EIB_CNT counter = 0 Rise EIB_UP_STEP ， EIB_CNT
counter =PWR_EIB_CNT
EIB_CNT counter != 0 Unchanged power
Bad EIB_CNT counter = 0 Fall EIB_DWNS_STEP
EIB_CNT counter != 0 Fall EIB_DWNB_STEP
Arithmetic of Forward Power ControlArithmetic of Forward Power Control
Theories of EIB Forward Power ControlTheories of EIB Forward Power Control

27.  Outer loop: The MS computes the
forward channel FER and then
compares with the target FER to get
the target Eb/Nt.
 Inner loop: The MS fills the power bit
in the subchannel of the reverse
power control by comparing the
target Eb/Nt with the measured
Eb/Nt.
 The forward quick power control bit
is sent through the reverse pilot
frequency channel.
Arithmetic of Forward Power ControlArithmetic of Forward Power Control
Theories of Forward Quick Power ControlTheories of Forward Quick Power Control

28. Definition Standards of Radio Configuration andDefinition Standards of Radio Configuration and
Protocol Version of the MSProtocol Version of the MS
 For the IS2000 and IS95/95B are backward compatible, the Rate
Set1 and Rate Set2 (as a subset of the IS2000) corresponds to RC1
and RC2.
Radio Configuration
Protocol Version of the MS
Protocol version of the MS:1-2:IS95, 3:IS95A,4-5:IS95B, 6:20001X

29. Application of the Power Control ArithmeticApplication of the Power Control Arithmetic
 Forward Power Control Is Based on the CDMA Standards:
 The MS with version 2-5 is allocated with the RC1 channel and
adopts the measurement report power control.
 The MS with version 3-5 is allocated with the RC2 channel and
adopts the EIB power control (prior choice) and the
measurement report power control as well.
 The MS with version later than 6 (including 6) adopts forward
quick power control (prior choice) and measurement report
and EIB control as well.
 Application of the Reverse Power Control
 The MS with version 2-7 adopts the same reverse power
control Arithmetic (open loop and closed loop).
At present, the Huawei system automatically chooses the power control
Arithmetic based on the protocol versions of the MS and radio
configuration.

30. QuestionsQuestions
 What are the categories of the power control?
 What are the mapping relations between the forward power control
and RC and the protocol version of the mobile phone?
 What are the theories of the forward quick power control and
reverse quick power control?

31. Chapter 1 Goals and Principles of Power Control
Chapter 2 Categories and Arithmetic of Power Control
Chapter 3 Data Configuration of Power ControlChapter 3 Data Configuration of Power Control
Contents

32. Data Configuration of Power ControlData Configuration of Power Control
 Parameters: NOM_PWR, INIT_PWR, PWR_STEP
 Brief Description: These parameters affect the power estimation of open loop power
control. Their influence begins at the first access probe transmission. They greatly
affect the access process and call establishment. For details, see CDMA 1x BSS
Parameter Configuration Guide and the previously described contents.
 Relevant Message: APM
 Balance Setting: If the values of the parameters are set too high, the parameters will
have great impact on the reverse capacity and redundant power is generated. If the
values are set too low, you may have to try many times before having the mobile phone
accessed to the channel and the access may even fail.
 Supplement: Parameter NOW_PWR and parameter INI_PWR has the same impact on
the first accessed probe. They are different from the perspective of physics. The effect
of their impact on the later probes differs.
 Command Line: MOD APM

33.  Parameter: RLGAIN_ADJ (link gain adjustment)
 Brief Description: After the access channel accesses the system, the
initial power (the reverse pilot frequency power for the IS2000) of the
traffic channel = the power of the current access channel + the value of
the parameter
 Relevant Message: ECAM
 Balance Setting: The greater the parameter value is, the higher are the
transmission quality during the initial period of the call and the establish
rate of the call. However the parameter will have impact on the system
capacity and increase the power consumption of the mobile phone.
 Command Line: MOD RCLPC
Data Configuration of Power ControlData Configuration of Power Control

34.  Parameters:
Minimum Eb/Nt value of the FCH
Maximum Eb/Nt value of the FCH
Initial Eb/Nt value of the FCH
 Brief Description: This group of parameters respectively indicate
the minimize, maximize and initial set values of the forward FCH
outer loop power control of the mobile phone.
 Relevant Information: ECAM
 Balance Setting: These values need to be balanced between the
voice quality, call drop rate and the forward system capacity. If
they are set high, the voice quality will be improved and the call
drop rate decreased but decrease the forward capacity.
 Command Line: MOD FFASTPC
Data Configuration of Power ControlData Configuration of Power Control

35. Data Configuration of Power ControlData Configuration of Power Control
Synchronous Switch of the FCH Power
 In the soft handoff, the ratios between the traffic channel powers of
different branches and the forward pilot channel power are the same.
The traffic channel consists of the FCH and the SCH.
 The synchronous switch is suggested to be on without A3/A7 soft
handoff.
 The synchronous switch is suggested to be off with A3/A7 soft
handoff, so are the BSC and the BTS sides.
Note
For V2R2, we can switch on the Power Synchronous Switch
after approved

36. SummarySummary
 Goals and Principles of Power
Control
 Categories of Power Control
 Arithmetic of Power Control
 Data Configuration of Power Control
ContentsContents