2_WCDMA Key Technology 78

8/8/2019 2_WCDMA Key Technology 78

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WR_BT04_E1_1WCDMA Key Technologies

ZTE UniversityWCDMA BSS Course

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Course Objectives

At the end of this course, you will be able to:

Master key technologies of WCDMA

Master characteristic of WCDMA system capacity



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Contents

WCDMA Key Technologies

Power Control

Handover Control

Admission Control

Load Control

Code Resource Allocation

RAKE Receiver

WCDMA Capacity Features



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n CDMA is not a new technology

n Power control is a key technology of CDMA system

n

Power control is the key path for launching the largescale CDMA commercial network

CDMA is a typical self-interference system, thus the chiefprinciple is that any potential surplus transmitted power for

service must be controlled.

CDMA is a typical selfCDMA is a typical self--interference system, thus the chiefinterference system, thus the chief

principle is that any potential surplus transmitted power forprinciple is that any potential surplus transmitted power for

service must be controlled.service must be controlled.

Power Control



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Why Power Control?

n

All CDMA users occupy the same frequencyspectrum at the same time! Frequency andtime are not used as discriminators.

n CDMA operates by using codes todiscriminate between users.

n CDMA interference comes mainly from

nearby usersn Each user is a small voice in a roaring

crowd -- but with a uniquely recoverablecode.

To achieve acceptable service quality, the transmit power of all users must betightly controlled so that their signals reach the base station with the same

signal strength and the absolute minimum power level demanded to avoid the

Near-Far Effect.



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Power

f

Overpowered by strong signalsBlock the whole cell

Near-Far Effect



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Each terminal is an interference

source to the others. The Near-fareffect will impact the capacity

tremendously

Each terminal is an interferenceEach terminal is an interference

source to the others. The Nearsource to the others. The Near--farfareffect will impact the capacityeffect will impact the capacity

tremendouslytremendously

Power

f

Power control will reduce the

cross interference significantly

and improve the total capacity

Power control will reduce thePower control will reduce the

cross interference significantlycross interference significantly

and improve the total capacityand improve the total capacity

Power

f

Power control



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Overcome near-far effect and compensate signal fading

Reduce multi-access interference and guarantee cell capacity

Extend battery life

Downlink Power Control

UE transmitted signal

Power control command (TPC)

Uplink Power Control

Cell transmitted power

Power control command (TPC)

Purpose of Power Control



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Category of Power control

UE

RNC

Node B

Open loop power controlno feedback

Close loop power controlfeedback

UE Node B

RNCOuter-loop

Inner-loop



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Open Loop

Measure the channel interference condition and adjust the initial transmittedpower

Close LoopInner LoopMeasure the SIR (Signal to Interference Ratio), compare with the target SIR

value, and then send power control instruction to UE.The frequency of WCDMA inner loop power control is 1500Hz.

If measured SIR>target SIR, decrease the UE transmitted power.

If measured SIR target SIR, decrease the UE transmitted power.

If measured SIR target BLER, decrease the target SIR value.

If measured BLERtarget BLER, decrease the target SIR value.

If measured BLER


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n General principals of open loop power control

Open loop power control is applied to estimate the initial

transmitted power for a new radio link.

P-CPICH signal is used in Downlink Open Loop Power Control,

which is measured by UE to estimate the initial transmitted power.

The following factors will also be considered, such as service QoS

and data rate, Eb/No requirements of establishing service, current

downlink total Transmitted Power and interference from neighbor cell

etc.

Open Loop Power Control



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Try to get the equal receivingEb (Energy per bit) of each

UE at Node B

Try to get the equal receivingTry to get the equal receivingEbEb(Energy per bit) of each(Energy per bit) of each

UE at Node BUE at Node B

NodeB UE

TPC instruction

Measure receiving SIR andcompare to target SIR

Inner loop

Set SIRtar

1500Hz1500Hz1500Hz

Each radio link hasits own control

circle

Each radio link hasEach radio link hasits own controlits own control

circlecircle

Close Loop Inner Loop Power Control



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n

General principals of inner loop power control The receiver compares the SIR value of received signal with target

SIR, and then sends back TPC instruction. According to the

instruction, the sender will decide to increase/decrease the

transmitted power. The adjusted rang=TPC_cmdTPC_STEP_SIZE

n Inner loop power control is required for the following channels

DPCH, PDSCH, PCPCH

n Inner loop power control is not required for the following

channels

P-CPICH(S-CPICH), P-CCPCH(S-CCPCH), PRACH etc.



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NodeB UE

TPC instruction

Inner loop

Set SIRtar

Get data flow

with stable BLER

Get data flowGet data flow

with stable BLERwith stable BLER

Measure BLER

of TRCH

Measure BLERMeasure BLERof TRCHof TRCH

Outer Loop

RNC

Measure receiving

BLER and compare to

target BLER

Set BLERtar

10-100Hz

Measure receiving SIR

and

compare to target SIR




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Close Loop Outer Loop Power Control

n Outer Loop Power Control algorithm

Employ the inner loop power control to keep SIR close to target

SIR.

Measure the quality of service, including target BLER, CRC

indicator and SIR Error, then set the value of SIR_Target.

Tune the target SIR with pre-defined step as the adjustment

parameter for inner loop power control to keep the service in good

quality in time-varying wireless propagation environment.

The uplink open loop power control algorithm is executed in the

RNC while the downlink one is executed in UE.



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The Effect of Power Control

n

The purpose of DL power control: Saving power resource of NodeB.

Reducing interference to other NodeB.

n The purpose of UL power control:

Overcoming Near-Far effect. Extending UE battery life.

WCDMA system capacity depends on the effect of power control



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Contents


Power Control

Handover Control

Admission Control

Load Control


RAKE Receiver




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Whats

n

When UE is moving from the coverage area of one site toanother, or the quality of service is declined by external

interference during a service, the service must be handed over to

an idle channel for sustaining the service.

n Handover is used to guarantee the continuity of service

n Handover is a key technology for mobile networking



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Category of Handover

n Intra-RNC, inter-Node B

n Inter-RNC

Soft handover (SHO)

n Same Node B, Inter-sector

Softer handover

n Intra-frequency

n Inter-frequency

n Inter-system (3G&2G)

n Inter-mode (FDD&TDD)

Hard handover (HHO)

WCDMA system support

multiple handover technology



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Handover Demonstration

Soft

Handover

Hard Handover



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A

B

C

A

B

C

A

B

C

A

B

C

A

B

C

A

B

C

Soft Handover/Softer Handover

Soft Handover

Soft-Softer Handover

Softer Handover



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Hard Handover

n During the hard handover procedure, all theold radio links with the UE are abandoned

before new ones are established, so there

must be service interruption during the HHO.

n Hard handover may occur in the following

main cases

When the UE is handed over to another

UTRAN carrier, or another technology mode.

When soft handover is not permitted (if O&M

constraint)

Hard Handover

Node B

SRNC

RNC or

BSC

CN

Node B or

BTS



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Soft/Softer Handover

n The soft/softer handover allows to migrate from one cell to

another without service interruption or without deleting all old

radio links.

n UE can connecte to more than one cell simultaneously and take

benefit from the macro-diversity.Soft Handover Softer Handover

CN CN

Iur

The two Node Bsmay belong to the

same RNC

The two Node Bs maybelong to the Same RNC

Soft Handover Softer Handover

SRNC DRNC

CN

Node B

SRNC

CN

Soft Handover Softer Handover

Node B

CN



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WCDMA General Handover Procedures---- Handover Trilogy

n Measurement Control UTRAN demands the UE to start measurement through issuing a

measurement control message.

n Handover decision

UTRAN makes the decision based on the measurement reports

from UE. The implementation of handover decision is various for

different vendors. It impacts on the system performance critically.

n

Handover execution UTRAN and UE execute different handover procedure according to

the handover command .



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General Procedure of Handover Control (I)

n Measuring

The measurement objects are decided by RNC. Usually, either

Ec/N0 or RSCP (Received Signal Code Power) of P-CPICH channel is

used for handover decision.

ZTE RNC adopts Ec/N0 measurement, because Ec/N0 embodies

both the received signal strength and the interference. The relation of

Ec/N0 and RSCP is shown as follows:

Ec/N0RSCP/RSSIIn the above equationRSSIReceived Signal Strength Indicator

is measured within the bandwidth of associated channels



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n

Reporting4Period report triggered handover

4Event report triggered handover

Base on the filtered measurement result

Base on the event

SoftHandover

HardHandover

Period

Event

Measurement result filtered in UE

Event decided in RNC

Handover decided in RNC

Measurement result filtered in UEEvent decided in UE

Handover decided in RNC

General Procedure of Handover Control (II)



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General Procedure of Handover Control (III)

n Handover algorithm

All the handover algorithms including soft handover, hard handover

and so on are implemented on the event decision made according

to the measurement reports.

n Events defined in 3GPP specifications

Intra-frequency events1A~1F

Inter-frequency events2A~2F

Inter-RAT events3A~3D

Note: RAT is short for Radio Access Technology, e.g. WCDMA&GSM



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Concepts Related to Handover

n Active Set:

A set of cells that have established radio links with a certain mobile station.

User information is sent from all these cells.

n Monitored Set:

A set of cells that are not in the active set but are monitored according to

the list of adjacent cells assigned by the UTRAN.

n Detected Set:

A set of cells that are neither in the active set nor in the monitor set.



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Soft handover process

n

Measurement RNC sends a measurement control message to UE.

UE should perform measurement as required and report the measurement result.

Generally, the measured parameter is the common pilots Ec/No.

n Decision

RNC stores data of different cells according to the measurement results.

RNC makes preliminary decision according to the event decision method.

e.g.

When the event is reported and the target cell is acceptable, send an active set

update command to add/delete the cell into/from the active set.

n Execution

The RNC sends an active set update command to UE and UE starts handover.



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Soft handover events

Event Description

1AQuality of target cell improves, entering a reportrange of relatively activating set quality

1BQuality of target cell decreases, depart from areport range of relatively activating set quality

1CThe quality of a non-activated set cell is better thanthat of a certain activated set cell

1D Best cell generates change

1E

Quality of target cell improves, better than an

absolute threshold

1FQuality of target cell decreases, worse than anabsolute threshold



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An Example of SHO Procedure

Pilot Ec/Io of cell 1

time

PilotEc/Io

Connect to cell1 Event 1A Event 1C Event 1B

add cell2replace cell1 with cell 3remove cell3



t t t



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Example of soft handover

U E T a rg e t N o d e B S o u rc e N o d e B R N C

R R C : M e a s u re m e n t R e p o r t( E v e n t 1 a ) (F r o m S o u r c e N o d e B t o R N C )

N B A P : R a d i o L in k S e t u p R e q u e s t

N B A P : R a d i o L i n k S e t u p R e s p o n s e

E x e c u t in g h a n d o v e r

j u d g e m e n t a n d

a d d i n g a r a d i o l i n k

i n T a r g e t N o d e B

S t a r t t o r e c e i v e

D i s tr ib u t i n g t r a n s m i s s i o n r e s o u r c e s o n I u b i n t e rf a c e

S t a r t to s e n d

R R C : A c t i v e S e t U p d a t e ( E 1 a ) (F r o m S o u r c e N o d e B to U E )

R R C : A c t iv e S e t U p d a te C o m p le t e ( F ro m S o u r c e & T a r g e t N o d e B t o R N C

s i m u t a n e o u s l y )

U E c o n n e c t s t o S o u r c e N o d e B a n d T a r g e t N o d e B s i m u t a n e o u s ly



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RNS Relocation

Core NetworkCore Network

ServingRNS

TargetRNS

Serving

RNSTargetRNS

Iu Iu

Iur

RNSRadio Network Sub-system

n

RNS relocation can: Reduce the Iur traffic significantly

Enhance the system adaptability



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Hard Handover

n Hard handover measurement is much more complex for UE

than soft handover measurement.

n Inter-frequency hard handover requires UE to measure the

signal of other frequencies.

n WCDMA employs compressed mode technology to support

inter-frequency measurement.



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Contents


Power Control

Handover Control

Admission Control

Load Control


RAKE Receiver




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Admission Control

n The admission control is employed to admit the access of

incoming call. Its general principal is based on the

availability and utilization of the system resources.

n If the system has enough resources such as load margin,

code, and channel element etc. the admission control will

accept the call and allocate resources to it.



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Purpose of Admission Control

n When user initiates a call , the admission control should

implement admission or rejection for this service according to the

resource situation.

n The admission control will sustain the system stability firstly and

try the best to satisfy the new calling services QoS request, such

as service rate, quality (SIR or BER), and delay etc. basing on the

radio measurement.

n Admission control is the only access entry for the incoming

services, its strategy will directly effect the cell capacity and

stability, e.g. call loss rate, call drop rate.


Ad i i C t l i U li k


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Admission Control in Uplink

Itotal_old+I >Ithreshold

The current RTWP (Received TotalWide Power) value of cell, which isreported by Node B

AccessThreshold

Interference capacityService priorityReserved capacity for

handover

Iown-cell

0

~N

Iother-cell

The forecasted interference including the delta

interference brought by the incoming service iscalculated by the admission algorithm, and itsresult depends on the QoS and transmissionpropagation environment


Ad i i C t l i D li k


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Admission Control in Downlink

Ptotal_old+

P>=PthresholdAccessThreshold

The forecasted TCP value including delta

power required for the incoming service iscalculated by the admission algorithm, and itsresult depends on the QoS and transmissionpropagation environment.

The current TCP value of cell, whichis reported by Node BTransmitted Carrier Power*Pmax

Max TCP of cellService priorityReserved capacity for

handover



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Contents


Power Control

Handover Control

Admission Control

Load Control


RAKE Receiver




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Load control

The purpose of load control is to keep the

system load under a pre-planned threshold

through several means of decreasing it, so as to

improve the system stability.

The speed and positionchanging of UE may

worsen the wireless

environment.

Increased transmitted

power will increase the

system load.

Purpose of Load Control


Load Control Flows


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Load Control Flows

Start

DecisionLight loaded Over loaded

Normal loaded

1.Handover in andaccess are forbidden2. TCP increase isforbidden

3. RAB service ratedegrade

4. Handover out5. Release call (call drop)

1. Handover in and accessare allowed

2. Transmitted code power(TCP) increase is allowed

3. RAB service rateupgrade is allowed

1. Handover inand access areallowed2. TCP increaseis allowed


L d C t l i U li k


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Load Control in Uplink

n Triggers

RTWP (Received Total Wide-band Power) value from measurement report

exceeds the uplink overload threshold;

Admission control is triggered when rejecting the access of services with lower

priority due to insufficient load capacity in uplink.

n

Methods for decreasing load Decrease the target Eb/No of service in uplink;

Decrease the rate of none real time data service;

Handover to GSM system;

Decrease the rate of real time service, e.g. voice call;

Release calls.

n Methods for increasing load

Increase the service rate.


Load Control in Downlink


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Load Control in Downlink

n Triggers

TCP (Transmitted Carrier Power) value from measurement report exceeds the

downlink overload threshold;

Admission control is triggered when rejecting the access of services with lower

priority due to insufficient load capacity in downlink.

n Methods for decreasing load

Decrease the downlink target Eb/No of service in downlink;

Decrease the rate of none real time data service;

Handover to coverage-shared light loaded carrier;

Handover to GSM system;

Decrease the rate of real time service, e.g. voice call; Release calls.

n Methods for increasing load

Increase the service rate.PDF created with pdfFactory Pro trial version www.pdffactory.com

Cell Breathing Effect


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Cell breathing is

one of the meansfor load control

The purpose of cell breathing is to share the load of hot-

spot cell with the light loaded neighbor cells, therefore to

improve the utilization of system capacity.

The purpose of cell breathing is to share the load of hotThe purpose of cell breathing is to share the load of hot--

spot cell with the light loaded neighbor cells, therefore tospot cell with the light loaded neighbor cells, therefore toimprove the utilization of system capacity.improve the utilization of system capacity.

Cell Breathing Effect


Example for load control


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Example for load control

Cell Breathing EffectCell Breathing EffectWith the increase of activated terminals and

the increase of high speed services,

interference will increase.

The cell coverage area will shrink.

Coverage blind spot occurs

Drop of call will happen at the edge of cellCoverage ancapacity areinterrelated



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Contents


Power Control

Handover Control

Admission Control

Load Control


RAKE Receiver



WCDMA Code Resource


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WCDMA Code Resource

n WCDMA code resource including

Channelized Code (OVSF code)

Uplink Channelized Code

Downlink Channelized Code

Scrambling Code (PN code)

Uplink Scrambling Code

Downlink Scrambling Code


Function of OVSF Code


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Function of OVSF Code

OC1, OC2

OC3, OC4

OC5, OC6, OC7

OC1 , OC2, OC3

OC1, OC2

OC1, OC2, OC3, OC4

Uplink: distinguish different radio channels from the same UE.

Downlink: distinguish different radio channels from the same NodeB.


Function of PN code


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Function of PN code

PN3 PN4

PN5 PN6

PN1 PN1

Cell Site 1 transmits using PN code 1

PN2 PN2

Cell Site 2 transmits using PN code 2

Downlink: distinguish different Cells

Uplink: distinguish different UEs


Why Code Resource Planning?


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n The OVSF (Orthogonal Variable Spreading Factor) code tree is a scarce

resource and only one code tree can be used in each cell. In order to

make full use of the capacity, and support as many connections as

possible, it is important to plan and control the usage of channel code

resource.

n Downlink PN code allocation should be planned to avoid the interference

between neighboring cells.

n The uplink PN codes are sufficient, but RNC should plan the codes to

use for avoiding allocating same code to different users in inter-RNC

handover scenario.

Why Code Resource Planning?


Code Resource Planning


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g

n The uplink and downlink scrambling code can be planned easily by computer.

n The uplink channelized code does not need planning, for every UE can use

the whole code tree alone.

n Therefore, only the downlink channelized code is planned with certain

algorithm in RNC.

n Each cell has one primary scrambling code, which correlates with a channel

code tree. All the users under this cell share this single code tree, so the

OVSF code resource is very limited.

n The downlink channelized code tree is a typical binary tree with each layer

corresponds to a certain SF ranging from SF4 to SF512.


Generation of Channelized Code


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SF = 1 SF = 2 SF = 4

Cch,1,0 = (1)

Cch,2,0 = (1,1)

Cch,2,1 = (1,-1)

Cch,4,0 =(1,1,1,1)

Cch,4,1 = (1,1,-1,-1)

Cch,4,2 = (1,-1,1,-1)

Cch,4,3 = (1,-1,-1,1)


OVSF Code Tree


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Channelized Code Characters


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S F = 8

SF = 3 2

SF = 1 6

n Code allocation restriction

The code to be allocated must fulfill the condition that its ancestor nodes

including from father node to root node and offspring nodes in the sub tree are

not allocated;

n Code allocation side effect

The allocated node will block its ancestor nodes and offspring nodes, thus the

blocked nodes will not be available for allocation until being unblocked .


Strategy of Channelized Code Allocation


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gy

n Full utilization

The fewer the blocked codes, the higher code tree utilization rate.

n Low Complexity

Short code first.

n Allocate codes for common channels and physical shared channels

prior to dedicated channels.

Guarantee the code allocation for common physical channels.

nApply certain optimized strategy to allocate codes for downlink

dedicated physical channels.


An Example of Code Allocation


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0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

SF = 4

SF = 8

SF = 16

SF = 32

SF = 4

SF = 8

SF = 16

SF = 32

Red spots represent the codes that have been allocatedGreen spots represent the codes that are blocked by the allocated offspring codesBlue spots represent the codes that are blocked by the allocated ancestor codes;

Black spots represent the codes that to be allocated;

Choose one

code from

three

candidates


Planning of downlink PN code


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PN1

PN2

PN3PN7

PN6 PN4

PN5

PN7

PN6 PN4

PN5

PN1

PN2

PN3

PN1

PN2

PN3PN7

PN6 PN4

PN5

PN1

PN2

PN3PN7

PN6 PN4

PN5

PN1

PN2

PN3PN7

PN6 PN4

PN5 PN1

PN2

PN3PN7

PN6 PN4

PN5



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Contents


Power Control

Handover Control

Admission Control

Load Control


RAKE Receiver



RAKE Receiver


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RAKE Receiver can effectively overcome the multi-pathinterference, consequently improve the receiving performance.

RAKE Receiver can effectively overcome the multiRAKE Receiver can effectively overcome the multi--pathpathinterference, consequently improve the receiving performance.interference, consequently improve the receiving performance.

n The multi-path signals contain some useful energy , therefore the

CDMA receiver can combine these energy of multi-path signals to

improve the received signal to noise ratio.

n RAKE receiver adopts several correlation detectors to receive the

multi-path signals, and then combines the received signal energy.


RAKE Receiving


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d1 d2

t t t

d3

transmitting ReceivingRake

combinationnoise


Multi-finger receiver


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n Traditional receiver

Multi-path signals are treated as interference.

The receiving performance will decline because of the Multi-address

Interference (MAI).

n Precondition of Multi-finger receiver

Multi-finger receiver utilizes the Multi-path Effect.

Multi-finger signals can be combined through relative process

Multi-finger time delay is larger than 1 chip interval, which is

0.26us=>78m.


Multi-finger receiver


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receivertransmitter

coding decoding

Direct signal

Reflected signal

Dispersive time < 1 chip interval

Multi-finger receiver cant supply multi-finger diversity

decoding

Direct signal

Reflected signaltransmitter receiver

Dispersive time > 1 chip interval

Multi-finger receiver can supply multi-finger diversity, signal gain is improved

coding


RAKE Receiving


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receiverreceiver

Single

receiving

Single

receiving

Single

receiving

searcher calculatecalculate

combining

tt

s(t) s(t)

signal

RAKE Receiving overcomes multi-finger interference, improvesreceiving performance


Combination of Multi-fingers


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n Maximal ratio combining (MRC)

at each time delay phase shifting by adding

Finger 1

Finger 2

Finger 3


C t t


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Contents


Power Control

Handover Control

Admission Control

Load Control


RAKE Receiver



Capacity of WCDMA


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ULcapacityisrestrainedby

interference

DLcapacityisrestrained

bythepowerofNodeB


Power Rising


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n Power rising occurs because of the Multiple Access Interference

(MAI) resulting from the non-orthogonal code channels.

WCDMA network Meeting Room

Code channel transmit talk with dialects Channel power voice tone

Promised channel quality listen clearly

Channel power rise voice tone rise

Power climb voice climb Collapse over the range can not hear each other


Power Rising


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Quantity of Subscriber

Quantity of Subscriber-- The Total Bandwidth Received by Node B


Capacity of WCDMA System


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=

=

=

Under the circumstance of single services::


Capacity of WCDMA System


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. . .

Under the circumstance of mixed services

X Y Z+ +




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n WCDMA capacity feature

WCDMA capacity is Soft Capacity.

n The Concept of Soft Capacity

The system capacity and communication quality are

interconvertible.

Different services have different capacity.

Different proportion of services have different capacity for

mixed services.

The capacity is also restricted to the allocation of code

resource.PDF created with pdfFactory Pro trial version www.pdffactory.com

Concept of Soft Capacity


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Different combinationof service hasdifferent capacity

Different

service has

different

capacity

System capacity and QoS can be interconvertedSystem capacity and QoS can be interconverted


Crucial Factors for WCDMA Network (CQC)


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Qua

lity

Qua

lity Cove

rage

Cove

rage

CapacityCapacity

All the key technologies adopted are used to try to

achieve the optimal balance of the three factors

All the key technologies adopted are used to try toAll the key technologies adopted are used to try to

achieve the optimal balance of the three factorsachieve the optimal balance of the three factors


Coverage and Capacity


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n WCDMA performance is determined by such factors as

Number of users

Transmission rate

Moving speed

Wireless environment

indoors Outdoors

n The radius of cell depends on such factors as:

Local radio conditions (local interference)

Traffic in neighbouring cells (remote interference)n Cell Radius decrease according to the Increase of user number


Coverage/capacity VS Data Rate


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n Higher data rate needs higher power

n High data rate transmission is only available nearby the station

>12.2 kbps

>64 kbps

>384 kbps

>144 kbps

Coverage decrease

Subscribernumincrease


Optimization methods


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t DL/UL:

w Add carrier

w six sectors

tUL

w Tower Mounted Amplifier (TMA)

w 4 Rx Divw OTSR

tDL

w

transmission diversity (Tx Div)w high power amplifier

Add basestation

last choice

Add basestation

last choice

n To overcome Cell Breathing Effect caused by increased traffic

and meet different requirements for capacity and coverage in

different environment, following solutions can be applied:


Factors affects WCDMA Capacity


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Wireless environment such as interferences, UE position and

mobility etc. can influent the cell capacity

WirelessEnvironment

The advanced receiving and baseband processing technology is

introduced to overcome the fast fadingRAKE Receiver

The Allocation of codes impacts the maximum number of

simultaneous connections.OVSF Code

Monitoring system load and adjusting the ongoing services to avoidoverload

Load Control

Admitting a connection base on the load and the admission

threshold of planned capacityAdmission Control

Impacting the capacity through applying different proportion and

algorithm of soft handoverHandover Control

Reducing interference, saving power and Increasing capacityPower Control

Impact on WCDMA capacityFactors


Documents

2_WCDMA Key Technology 78