3g basic theory 02
Post on 02-Apr-2015
778 Views
Preview:
TRANSCRIPT
Soc Classification level 1 © Nokia Siemens Networks Presentation / Author / Date
3G BASIC THEORY
UMTS TECHNOLOGY
Soc Classification level 2 © Nokia Siemens Networks Presentation / Author / Date
WHAT IS 3G?WHAT IS 3G?
- stands for THIRD GENERATION mobile technology
- NTC clarified it viewed 3G as enhancement and improvement of the 2nd Generation Technology
- it is a wireless technology designed to allow a certain device to access to voice, video and data services at much faster rates than can be achieved today
Soc Classification level 3 © Nokia Siemens Networks Presentation / Author / Date
OBJECTIVE:OBJECTIVE:To EXPLORE:
- The History and roadmap of mobile Telecommunication
- 3G Basic Technology
- 3G Basic Network Architecture
- 3G Basic Nature and Behavior
Soc Classification level 4 © Nokia Siemens Networks Presentation / Author / Date
Soc Classification level 5 © Nokia Siemens Networks Presentation / Author / Date
The mobile communications industry has evolved in three stages:
Voice call Voice call,fax, data and text messaging
1G 2G – 2.5 G 3G
High speed data transfer.
New video, audio and Mobile TV,Internet browsing and Music download
Soc Classification level 6 © Nokia Siemens Networks
1976+, though really the technology of the 1980’s
Analogue modulation
Frequency Division Multiple Access
Voice traffic only
No inter-network roaming possible
Not secure air interface
1st Generation
The 1st Generation of Cellular Technology makes use of analog modulation techniques such as FM
Soc Classification level 7 © Nokia Siemens Networks
AMPS (Analogue Mobile Telephony System)
• North American Standard in cellular band (800MHz)
TACS (Total Access Communications System)
• UK originated Standard based on AMPS in 900MHz band
NMT (Nordic Mobile Telephony System)
• Scandinavian Standard in 450MHz and 900MHz bands
C-450
• German Standard in 450MHz band
JTACS (Japanese Total Access Communications System)
• Japanese Standard in 900MHz band
1st Generation Standards
Soc Classification level 8 © Nokia Siemens Networks
1st Generation Planning
Macrocellular◦ High sites for coverage driven
planning◦ Antennas above roof height
Frequency planning required Large cell size
◦ Order 30km Hard handover
◦ Only ever connected to a single cellCellular Networks are commonly represented as hexagon grids.
The above diagram shows how different frequencies are used in different cells in a cellular network (different frequencies represented by different colors).
For networks with more cells than frequencies these must be planned
Soc Classification level 9 © Nokia Siemens Networks
2nd Generation
1990’s Digital modulation Variety of Multiple Access
strategies Voice and low rate circuit switched
data Same technology roaming Secure air interface
000110100110
111001001111
000
001001011110011110001011000001001
00
The 2nd Generation of Cellular Technology is the first to use digital modulation
Soc Classification level 10 © Nokia Siemens Networks
1st and 2nd Generation Cellular Systems Overview
GSM
First networks in 1992
European developed standard, but with worldwide subscriber base
Different frequency bands
• GSM450, GSM900, GSM1800, GSM1900
Largest 2nd Generation subscriber base
Frequency/Time Division Multiple Access
Open/Standardised Interfaces
GSM phones from 1999/2000
Soc Classification level 11 © Nokia Siemens Networks
GSM Planning
Macrocells and microcells◦ Capacity driven planning
Frequency planning required Optional parameters requiring
planning◦ Hierarchical Cell Structures◦ Frequency Hopping◦ Discontinuous Transmission◦ Power Control
Simple subscriber/traffic analysis◦ Capacity limited by number of
TRX’s Hard Handover
GSM networks use microcells to provide additional capacity. As with 1st generation networks frequency planning is required
Soc Classification level 12 © Nokia Siemens Networks
First networks in 1996
Derived from Qualcomm IS-95 air interface
Largely American subscriber base with some Asian networks
Code Division Multiple Access• This is in many ways the closest 2nd generation standard to many of the 3rd
generation standards
ANSI-41 core network
Chip rate of 1.2288Mcps
cdmaOne
cdmaOne phones from 1999/2000
Soc Classification level 13 © Nokia Siemens Networks
cdmaOne Planning
Macrocells and microcells Single Frequency
◦ multiple frequencies for hotspots Soft Handover (multiple
connections between mobile and network)
Code Planning Capacity Interference Limited
Unlike GSM there is no frequency planning required for cdmaOne
However soft handover means that there are zones where there are two/three connections to the network
13
Soc Classification level 14 © Nokia Siemens Networks
2.5G
Now... Digital modulation Voice and intermediate rate
circuit/packet switched data Same technology roaming Secure air interface Based upon existing dominant
standards such as GSM or cdmaOne
2.5G technologies are based upon existing 2G technologies but are focussed at increasing the maximum data rates that the technologies can deliver
14
Soc Classification level 15 © Nokia Siemens Networks
HSCSD
High Speed Circuit Switched Data
Enhancement to the GSM standard
Utilises:• Multiple channel coding schemes
(4.8kbps, 9.6kbps, 14.4kbps per timeslot)
• Multiple timeslots
Circuit Switched Data rates to 57.6kbps (4 slots with 14.4kbps channel coding per slot)
Nokia Cardphone
15
Soc Classification level 16 © Nokia Siemens Networks
General Packet Radio Service
Enhancement to the GSM standard
Utlilises• Multiple Channel Coding Schemes (9.05kbps, 13.4kbps, 15.6kbps, 21.4kbps)
• Multiple Timeslots
• Packet Switching
Packet Switched Data typically to rates of 115kbps • Theoretically 171.2kbps for 8 timeslots
GPRS
16
Soc Classification level 17 © Nokia Siemens Networks
Enhancement to cdmaOne standard
Utilises• High rate coding scheme
• Combined code channels
• packet switching
Packet Switched Data to rates of 114kbps
IS-95B
17
Soc Classification level 18 © Nokia Siemens Networks
Enhanced Data for GSM Evolution
• Sometimes called E-GPRS (Enhanced GPRS)
Enhancement to the GSM and TDMA standards
Utlilises:
• 8PSK Modulation
• Possible 1.6MHz carrier under IS-136
• 8 Channel Coding Schemes
• Multiple Timeslots
• TDMA
Data up to rates of 384kbps (typically less)
EDGE
18
Soc Classification level 19 © Nokia Siemens Networks
2G and 2.5G Standards Compared
GSM TDMA cdmaOne PDCMultipleAccess
TDMA TDMA CDMA TDMA
Modulation GMSK /4-DQPSK QPSK /4-DQPSK
CarrierSpacing
200kHz 30kHz 1.25MHz 25kHz
Frame Length 4.615ms 40ms 20ms 20ms
Slots perFrame
8 6 1 3/6
FrequencyBand
450/ 900/ 1800/1900
800/ 1900 800/ 1900 850/ 1500
Max DataRate
HSCSD:115kbps
GPRS: 115 –172kbps
IS-136+:43.2kbps
IS-95A:14.4kbpsIS-95B:
115.2kbps
28.8kbps
FrequencyHopping
Yes No N/A No
Handover Hard Hard Soft Hard
19
Soc Classification level 20 © Nokia Siemens Networks Presentation / Author / Date
Soc Classification level 21 © Nokia Siemens Networks Presentation / Author / Date
3G SERVICES 3G SERVICES
Soc Classification level 22 © Nokia Siemens Networks Presentation / Author / Date
3G – 3rd Generation: Digital Cellular –
1) Feature: – Wide band code division multiple access (WCDMA)
technology– digital signal– Broadband (5Mhz Bandwidth)– integrated service system integrating all current mobile
telephone system functions providing multiple services– large capacity
2) Radio Frequency Spectrum (UHF – Ultra high Frequency)– frequency spectrum around 2000MHz or 2GHz – Data rate up to 2000kbps or 2Mbps
Soc Classification level 23 © Nokia Siemens Networks Presentation / Author / Date
What triggered them to implement 3G?What triggered them to implement 3G?
Voice services currently account for more than 90 percent of income, but by the year 2005 it has been forecasted that data and other non-voice services will generate 50 percent of operator income.
Soc Classification level 24 © Nokia Siemens Networks Presentation / Author / Date
What is IMT-2000What is IMT-2000
"International Mobile Telecommunications – 2000 (IMT-2000)
represents the global standard for meeting the emerging needs of
mobile telecommunications in the 21st century whereby mobile
telecommunications subscribers will be able to access voice, data,
Internet, and multimedia services at any time and at any place."
Soc Classification level 25 © Nokia Siemens Networks Presentation / Author / Date
The Goal of IMT 2000
- Higher transmit rate 2Mbps
- Rich and colorful service
- Good voice quality
- Larger capacity
- Lower cost
- Good security performance
- High frequency efficiency
- Increased Mobility
- Easy to transition from 2G
Soc Classification level 26 © Nokia Siemens Networks Presentation / Author / Date
U101 26
IMT-2000 Candidate Harmonization
A number of technologies were submitted many of which had distinct similarities
Of course operators were generally keen on a single standard to allow global roaming and economies of scale• Operators Harmonization Group (OHG)
This led to two partnership projects being set up:• 3rd Generation Partnership Project (3GPP)
– Dealing with WCDMA (Also Known as Universal Mobile Telephone Systems UMTS) and related candidate technologies
• 3rd Generation Partnership Project 2 (3GPP2)– Dealing with cdma2000 and related candidate
technologies
Soc Classification level 27 © Nokia Siemens Networks Presentation / Author / Date
IMT 2000 Roadmap
HSDPA HSUPA
3GPP 3GPP23rd Generation Partnership Project
Soc Classification level 28 © Nokia Siemens Networks Presentation / Author / Date
Where is Philippines?Where is Philippines?
Soc Classification level 29 © Nokia Siemens Networks Presentation / Author / Date
1920M1920M 1980M1980M
( Uplink : 1920-1980 )
2110M2110M 2170M2170M
( Downlink : 2110-2170 )
1920-1980 2110-2170
Uplink Downlink
NTC Spectrum Allocation for WCDMA
Soc Classification level 30 © Nokia Siemens Networks Presentation / Author / Date
1920M
1920M
1980M
1980M
( Uplink : 1920-1940 )
2110M
2110M
2170M
2170M
( Downlink : 2110-2130 )
1920-1940 2110-2130
Uplink Downlink
NTC Allocated for GLOBE 3G (WCDMA)
1960M
1960M
1980M
1980M
( Uplink : 1960-1980 )
2110M
2110M
2170M
2170M
( Downlink : 2110-2170 )
1960-1980 2150-2170
Uplink Downlink
Soc Classification level 31 © Nokia Siemens Networks Presentation / Author / Date
RADIO FREQUENCIES
Where IS UMTS FREQ ?Where IS UMTS FREQ ?
Soc Classification level 32 © Nokia Siemens Networks Presentation / Author / Date
Globe needs these 3G frequency spectra to upgrade its current CMTS (Cellular Mobile Telephone System) services to 3G.
Globe will remit the corresponding spectrum user fees and post a performance bond equivalent to P300 million to the NTC to comply with the rules on the allocation of 3G radio frequency bands.
Soc Classification level 33 © Nokia Siemens Networks Presentation / Author / Date
HIERARCHICAL CELL STRUCTURES
Pico Cell
Few meters to 100
Micro cell
200 -500 meter range
Macro Cell
Few meters to 100
Soc Classification level 34 © Nokia Siemens Networks Presentation / Author / Date
HIERARCHICAL CELL STRUCTURESMacro Cells - carry the faster-moving wide-area traffic.
Micro Cells carry the higher-data-rate pedestrian traffic.
Pico Cells are deployed to cover ‘hot spots’ to relive capacity bottlenecks such as in offices or airports where user density is particularly high.
Soc Classification level 35 © Nokia Siemens Networks Presentation / Author / Date
WHAT IS WCDMA?
- stands for Wide-Band Code Division Multiple Access
- is a type of Cellular Network
- it is the higher speed transmission protocol used in the UMTS (Universal Mobile Telephone Systems)
Soc Classification level 36 © Nokia Siemens Networks Presentation / Author / Date
W-CDMA is a wideband spread-spectrum mobile
Air-interface that utilizes the direct-sequence spread
Spectrum method of asynchronous code division
multiple access to achieve higher speeds and
support more users compared to the implementation
of time division multiplexing (TDMA) used by
2G GSM networks.
Soc Classification level 37 © Nokia Siemens Networks Presentation / Author / Date
What is Bandwidth?
Bandwidth is the difference between the upper and lower cutoff frequencies, and is typically measured in hertz
Soc Classification level 38 © Nokia Siemens Networks Presentation / Author / Date
What is the Bandwidth?
1920M1920M 1925M1925M
5Mhz
Soc Classification level 39 © Nokia Siemens Networks Presentation / Author / Date
What is Code?
A code is a rule for converting a piece of information (for example, a letter, word, phrase, or gesture) into another form or representation (one sign into another sign), not necessarily of the same type.
Soc Classification level 40 © Nokia Siemens Networks Presentation / Author / Date
Example of a Code?
Soc Classification level 41 © Nokia Siemens Networks /
• Scrambling Codes – Are used to separate cells and terminals from each other rather than
purely channels
A UE is surrounded by Base Stations, all of them transmitting on the same CDMA Frequency.
A UE must be able to discriminate between different Sectors of different Node B’s.
The Downlink Scrambling Codes can be used in 512 different ways in a CDMA system. Each one of them constitutes a mathematical code which can be used to identify a particular sector.
.
A BCode ChannelsScrambling Code 1
Code ChannelsScrambling Code 2
WCDMA CODE Scrambling Code
Soc Classification level 42 © Nokia Siemens Networks Presentation / Author / Date
What is Multiple Access?
Imagine you are in a cocktail party…
Now imagine you are trying to talk to somebody
If you are trying to listen to somebody you need to be able to pick out their speech from everybody else’s speech
Everybody is using the same medium to talk – the air in the room
There are a number of different Multiple Access strategies…
Simultaneous private use of a transmissionmedium by multiple, independent users.
Soc Classification level 43 © Nokia Siemens Networks Presentation / Author / Date
What is Channel?
An individually-assigned, dedicated pathwaythrough a transmission medium for one user’s information.
Soc Classification level 44 © Nokia Siemens Networks Presentation / Author / Date
What is Transmission Medium
The transmission medium is a resource that can be subdivided into individual channels according to the technology used.
Each pair of users enjoys a dedicated,
private circuit through the transmission
medium, unaware that the other users exist.
Transmission
Medium
Soc Classification level 45 © Nokia Siemens Networks Presentation / Author / Date
Types of Multiple AccessA. FDMA Frequency Division Multiple Access• Each user on a different frequency• A channel is a frequency
Soc Classification level 46 © Nokia Siemens Networks Presentation / Author / Date
Types of Multiple AccessB. TDMA Time Division Multiple Access• Each user on a different window period in time (“time slot”)• A channel is a specific time slot on a specific frequency
Soc Classification level 47 © Nokia Siemens Networks Presentation / Author / Date
Types of Multiple AccessC. CDMA Code Division Multiple Access• A channel is a unique code pattern• Each user uses the same frequency all the time, but
mixed with different distinguishing code patterns
Soc Classification level 48 © Nokia Siemens Networks Presentation / Author / Date
CDMA Code Division Multiple Access
Frequency reuse factor is 1;network design and expanding become much easier
Frequency reuse factor is 1;network design and expanding become much easier
CDMA
5 MHz
1
1
11
1
11
11
1
11
1
1
Typical Frequency Reuse N=1
Soc Classification level 49 © Nokia Siemens Networks Presentation / Author / Date
TRADITIONAL COMMUNICATION SYSTEM
TRADITIONAL COMMUNICATIONS SYSTEM
SlowInformation
Sent
TX
SlowInformationRecovered
RX
NarrowbandSignal
Traditional technologies try to squeeze the signal into the minimum required bandwidth
Soc Classification level 50 © Nokia Siemens Networks Presentation / Author / Date
WCDMA COMMUNICATION SYSTEM
Spread spectrum systems mix their input data with a fast spreading sequence and transmit a wideband signal
The spreading sequence is independently regenerated at the receiver and mixed with the incoming wideband signal to recover the original data
.
SPREAD-SPECTRUM SYSTEM
FastSpreadingSequence
SlowInformation
Sent
TX
SlowInformationRecovered
RX
FastSpreadingSequence
Wideband Signal
Soc Classification level 51 © Nokia Siemens Networks Presentation / Author / Date
SPREAD SPECTRUM SYSTEM HISTORY
Soc Classification level 52 © Nokia Siemens Networks Presentation / Author / Date
What is SPREAD SPECTRUM SYSTEM?
Spread Spectrum techniques are methods by which more frequency bandwidth is deliberately used than motivated by the actual information rate (spectrum spreading). On one hand, this implies a certain waste of valuable frequency spectrum; but on the other hand,these techniques have advantages such as increasing the resistance to interference,jamming and interception.
Soc Classification level 53 © Nokia Siemens Networks Presentation / Author / Date
Spread Spectrum Principles
Shannon's FormulaShannon's Formula
C=B*log2(1+S/N)
Where, C is capacity of channel, b/s B is signal bandwidth, Hz S is average power for signal N is average power for noise
Claude Shannon is the Father of Information Theory. It was entirely new that information of any kind-- whether for use on a telegraph, telephone, radio, or television-- could be decomposed into zeros and ones, encoded, transmitted, and decoded at the other end which is called the Mathematical Theory of Communication. He went on to present the concept of the maximum rate of transmission on a channel-- the capacity or "Shannon limit"-- which provides the benchmark against which all codes and modulations are measured.
Claude Shannon is the Father of Information Theory. It was entirely new that information of any kind-- whether for use on a telegraph, telephone, radio, or television-- could be decomposed into zeros and ones, encoded, transmitted, and decoded at the other end which is called the Mathematical Theory of Communication. He went on to present the concept of the maximum rate of transmission on a channel-- the capacity or "Shannon limit"-- which provides the benchmark against which all codes and modulations are measured.
Soc Classification level 54 © Nokia Siemens Networks Presentation / Author / Date
SPREAD SPECTRUM SYSTEM ILLUSTRATION
5 MHz12.2 KHz
Power is “Spread” Over a Larger Bandwidth
MATHHAMMER
MATHHAMMER
Soc Classification level 55 © Nokia Siemens Networks Presentation / Author / Date
SPREAD SPECTRUM SYSTEM
I. Frequency-Hopping Spread Spectrum (FH-SS)
The SS technique Frequency-Hopping Spread Spectrum (FH-SS) involves transmitting a signal with a “normal” bandwidth over a carrier frequency that rapidly changes within a wider frequency spectrum.
To decode the signal, thereceiver in the FH-SS system needs to know the frequency-hopping sequence – the“code.”
FH-SS was first developed by scientist Nicola Tesla around 1900
Soc Classification level 56 © Nokia Siemens Networks Presentation / Author / Date
SPREAD SPECTRUM SYSTEM
II. Direct Sequence Spread Spectrum (DS-SS)
It is SS principle wherein the carrier frequency stays the same, but instead the signal to be transmitted is multiplied with a high bandwidth signal.
On the receiving end, the reproducible high bandwidth signal – the “code” – is multiplied with the received signal to recover the original signal.
Soc Classification level 57 © Nokia Siemens Networks Presentation / Author / Date
U101 57
Tx Bit Stream
Rx Bit Stream
Code Chip Stream (Spreading Code)
Air Interface Chip Stream
1
-1X
X
Spreading
Despreading
Spread
SPREADIND AND DESPREADING
1
-1
Code Chip Stream (Spreading Code)
Soc Classification level 58 © Nokia Siemens Networks Presentation / Author / Date
What is CHIP?
It is a pulse of a direct-sequence spread spectrum (DSSS) Code
WCDMA CHIP RATE: 3.84 Mcps
1
-1
pseudo-noise code sequence
Soc Classification level 59 © Nokia Siemens Networks Presentation / Author / Date
UMTS Architecture
Iu
Iur
RNC
RNC: RadioNetwork
ControllerSGSN
GGSN
AuCHLREIR
VLR
G-MSC
MSC
cellcell
cellcell
cellcell
cellcell
cell
Uu
US
IMU
SIM
US
IM
FDD modeonly
UE: User Equipment N
od
e BN
od
e BN
od
e B
RNS: Radio Network Subsystem
RNS
CN: Core Network
IuCS
IuPSIub
Gc
Gr
Gs Gf
D
B
F C
PSTN
EE
GiGn
Gp
ME
ME
ME
Soc Classification level 60 © Nokia Siemens Networks Presentation / Author / Date
UMTS - GSM Architecture
A-bis
Iub
Interface
Interface
Soc Classification level 61 © Nokia Siemens Networks Presentation / Author / Date
UTRAN (Universal Terrestrial Radio Access Network) Structure
RNS RNS
NodeB NodeBNodeB NodeB
RNC
CN
RNC
Iu Iu
Iur
Iub IubIub Iub
UE
UuUTRAN UTRAN
Soc Classification level 62 © Nokia Siemens Networks Presentation / Author / Date
UMTS Architecture
The system consists of:
• UTRAN
UTRAN performs all the functions related to wireless communication;
• CN (Core Network)
CN switches and routes voice and data services to connect them to the external network.
• UE (User Equipment)
The UE (User Equipment) is connected to the UTRAN through the air interface standard.
Soc Classification level 63 © Nokia Siemens Networks Presentation / Author / Date
Functional Units
UE (User Equipment):
As the wireless terminal that performs wireless communication via the Uu interface, it contains an intelligent card, which records the user ID, performs the authentication algorithm, and stores information such as authentication information and keys.
Node B:
Transmits data streams between the Iub and the Uu interfaces, participating in radio resource management.
RNC (Radio Network Controller): Owns and controls the radio resources under its
administration. The RNC is the service access point provided by the UTRAN for the CN.
Soc Classification level 64 © Nokia Siemens Networks Presentation / Author / Date
INTERFACE
Uu interface:
Serves as the air interface of the WCDMA system to connect a UE to a Node B.
Iu interface: Connects the UTRAN and the CN. It is similar to the A
interface (circuit switching) and the Gb interface (packet switching) in GSM.
Iur interface:Allows soft handover between the RNC equipment of
different manufacturers as an open interface.
Iub interface:
Connects the Node B and the RNC.
Soc Classification level 65 © Nokia Siemens Networks Presentation / Author / Date
WCDMA Basic Nature and Behavior - Cell Breathing
Breath effect of cell
• With the increase of activated
terminals, interference increase
• the increase of high speed service,
the increase of interference
• The shrink of cell coverage area
• Coverage blind spot occurs
• Drop of call will happen at the edge of cell
Coverage and capacity are
relative
backback
Soc Classification level 66 © Nokia Siemens Networks Presentation / Author / Date
Coverage/capacity vs Data Rate
>12.2 kbps
>64 kbps
>384 kbps
>144 kbps
Coverage decrease
Subscriber num increase
Higher rate needs higher power
High data rate transmission is only available nearby the station
Soc Classification level 67 © Nokia Siemens Networks Presentation / Author / Date
Multipath Propagation
Received SignalReceived Signal
TimeTime
StrengthStrength
00
TransmitTransmit
Soc Classification level 68 © Nokia Siemens Networks Presentation / Author / Date
Multipath Propagation
Soc Classification level 69 © Nokia Siemens Networks Presentation / Author / Date
RAKE Receiving
RAKE improve receive capability
receiver
Single receiving
Single receiving
Single receiving
searcher calculate
combining
tt
s(t) s(t)
signal
Soc Classification level 70 © Nokia Siemens Networks Presentation / Author / Date
Use handoff: minimize drop-call rateUse handoff: minimize drop-call rate
WCDMA Behavior: HANDOVER
sssssssss
Handover is the process of shifting a mobile device’s connection from one Node B to another
Soc Classification level 71 © Nokia Siemens Networks Presentation / Author / Date
TYPES OF HANDOVER
I. Intra-System (WCDMA) Handover a. SOFTER HANDOVER Mobile Station handover within one node B between different sectors –
b. SOFT HANDOVER - Mobile Station handover between different Node B.
c. Hard HANDOVER - Mobile Station handover between different frequencies
II. Inter-System HandoverHandover between WCDMA <--> GSM (Hard)
Handover between WCDMA/FDD <--> TDD (Hard)
Soc Classification level 72 © Nokia Siemens Networks /
WCDMA Power ControlWhy need Power Control?
- All User Equipment transmit on the same frequency
- UE with low path loss will cause large interference
- Removes Near –Far Effect – Variation of power level and interference due to distance and fading
Soc Classification level 73 © Nokia Siemens Networks /
WCDMA Power Control
•Goal: Adjust transmit power so that all mobile terminals are received with approximately the same power
•Set PTX,1 and PTX,2 so that PRX,1 ~ PRX,2
Soc Classification level 74 © Nokia Siemens Networks /
WCDMA Power Control
Open loop power control (No feed Back from the Node B)
If received signal is stronger,then UE can transmit lowerIf received signal is weaker,then UE can transmit stronger
To provide a course initial power setting of the mobile station at the beginning of a connection.
Closed Loop - With feed back from the Node B. Base station informs mobile unit to increase or decrease the power level
Soc Classification level 75 © Nokia Siemens Networks
To find roughly (estimate) min. power of UE to send on RACH (UL) to NodeB
Calculation based on DL path-loss and system information block in BCH
UE power (Initial DPCCH Power)
Open loop power control
Soc Classification level 76 © Nokia Siemens Networks
Closed Loop Power Control
top related