dr. dóra maros. korszerű mobil rendszerek evolution of communication

Modern mobile networks

Dr. Dóra Maros

Korszerű mobil rendszerek

Evolution of Communication


…..mobile phones….are also developed


…the beginnings….


Comité Européen de Normalisation Électrotechnique;

European Telecommunications Standards Institute

International Telecommunication Union

International Electrotechnical

CommissionInternational Organization

for Standardization

Regulatory Organizations


Institute of Electrical and Electronics

Engineers Internet Engineering

Task Force

International

International Federation for Information Processing

Hungarian

Independent Organizations


Generations of Mobile Networks (2G - 3G+)


After 3G


900 MHz-2,6 GHz

Electromagnetic Wave Spectrum


FDMA (Frequency Division Multiple Access)

Frequency

ITime

TDMA (Time Division Multiple Access)

CDMA (Code Division Multiple Access)

Frequency

ITime

Frequency

Time

The users share the available frequency bands in the cell

NMT 450 GSM UMTS

Multiple Division Access Technologies

OFDMA (Orthogonal Frequency Division Multiple Access)

ITime

Frequency

LTE


Same frequency band butTDMA:

Different time

CDMA: Different

codes

FDMA: different

frequency bands

OFDMA: multiple

frequency bands in the same time

Single Carrier and Multi Carrier Systems

Single carrier

Multi carrier


FDD (Frequency Division Multiplex) Different frequency bands for downlink and uplink Jelenleg preferált megoldás Benefits: speech, videophone, real time connection Disadvantage: if assymetric load , unsufficient band usage

TDD (Time Division Multiplex) Same frequency band for downlink and uplink Future applications Benefits: sufficient band usage Disadvantage: correct timing

Types of Duplexing


Downlink

Uplink

FDD: Frequency Duplexing

One channel bandwidth:

GSM :200 KHz UMTS: 5 MHzLTE: 20 MHz

TDD: Time DuplexingUL and DL on the same bandwidth, but in different times (UMTS és LTE)

B(dl): bandwidth

B(ul)

B(dl)=B(ul)

fk(dl)

fk(ul): center frequency

fk(dl)-fk(ul)= duplex distance

Downlink

Uplink

idő

Duplexing on Radio Interface


GSM 900, 1800, 1900 bands (2G)


Duplexing Uplink Downlink Bandwidth

UMTS-FDD 1920 - 1980 MHz 2110 - 2170 MHz 60 + 60 MHz

UMTS-TDD 1900 - 1920 MHz UL/DL2010 - 2025 MHz

UL/DL20 + 15 MHz

Satelite 1980 - 2010 MHz 2170 - 2200 MHz 30 + 30 MHz

in 2000, new frequency bands 806 - 960 MHz, 1710 - 1885 MHz (GSM

bands!) 2500 - 2690 MHz

DEC

TGSM1800

1800 1900 2000 2100 2200 2500 2600 2700

UMTSFDD

Mű

hold

UM

TS

TD

D

UM

TS

TD

D

UMTSFDD

Mű

hold

UMTS

[MHz]

Paired fr. bands

Unpaired fr. bands

Channel bandwidth: 5,10, or 20 MHz

UMTS Frequency Bands


30 bands:21 FDD9 TDD

LTE Bands


TDD Spectrum Allocation


ClassesConversation

alStreaming Interactive Background

Delay

Response time

between the users

Response time of demand

Response time of server

Not relevant

<< 1 s ~ 1s < 10 s > 10 s

Error Tolerance? Yes Yes No No

Switching Mode

Typical: Circuit

Switched

Packet Switched

Packet Switched

Packet Switched

ServiceSpeech

Videophone

Streaming

multimedia

Web browsing

Databases

Email, SMS,

MMS…

QoS Classes


Conversational Cl Speech

▪ Symmetric load▪ Round Trip Time < 400 ms ▪ AMR (Adaptive Multi-rate) codec▪ AMR-WB (AMR Wideband) codec (Release 5)

▪ Sampling: 16 kHz (instead 8 kHz)▪ Good quality ▪ Adative Multirate (AMR) codecs: 24 ÷ 6,6 kbps

Videophone▪ Circuit Switched: H. 324▪ Packet Switched: SIP (Session Initiation Protocol)

Conversational Class


Streaming Assymetric load Services:

▪ Web broadcast (a lot of users connect to mediaserver) ▪ Video on Demand

Interactive Tranzaction-oriented services

▪ Applications: databases, web browsing▪ Protocolls: HTTP, DNS stb▪ Assymetric, short switching time

Background Lowest priority, messages• MMS, SMS, E-mail

Other QoS Classes


For each 3G (UMTS) service classes different (SW and PW): Delay Bit error rate (BER) Data rate

Near future: Services are based on packet switching solutions (IP) instead circuit switched networks 4 QoS (Quality of Service) Class using IP Delay time Packet Loss Ratio Packet jitter Buffer size CODEC rate

Features of 3G Services


ME:Mobile Equipment radio terminal: voice, audio, video, internet, navigation, etc.

services

USIM (UMTS SIM) Similar to GSM SIM, but more features, capacity

USIM

ME

UE

Mobile Equipment

UMTS Subsciber Identity Modul

User Equipment (UE)


Cells and Datarates (Release 99)

HSDPA (from Release 5) High Speed Downlink Packet Access: >10Mbit/s

Earth Cell(satelite)

MacrocellSize: 350m-20 kmDatarate: 384 kbit/sOutdoor, rural, roads

MicrocellSize: 50m-300 mDatarate: 384 kbit/sOutdoor, city

PicocellSize: some 10 mDatarate: 2 Mbit/sIndoor


MSBTS

BSC

MSC/VLR

SGSN

BTS

HLR

GMSC

Internet

PLMN, ISDN

GERANCN:Core Network

Other networks

GGSN

MS= ME+SIM

Circuit Switched (CS)

Packet Switched (PS)

MS: Mobile Station BTS: Base Transceiver Station BSC: Base Station Controller PCU: Packet Contol Unit MSC: Mobile Switching (Serving) Center GMSC: Gateway MSC VLR: Visitor Location Register HLR: Home Location Register AUC: Authentication Center SGSN: Serving GPRS Support Node GGSN: Serving GPRS Support Node EIR: Equipment Identiy Register

AUC

PCU

PCU

EIR

GSM network (2.5 G)


UE Node B

RNC

MSC/VLR

SGSN

Node B

HLR

GMSC

Internet

PLMN, ISDN

UTRAN CN:Core Network

Other Networks

GGSN

UE

Circuit Switched (CS)

Packet Switched

UE: User Equipment UTRAN: UMTS Terrestrial Radio Access Network

Node B: Base Station RNC: Radio Network Controller

AUCEIR

UMTS network (Release 99)


MGW: Media Gateway HSS: Home Subscriber Server MRF: Media Resource Function CSCF: Call Session Control Function MGCF: Media Gateway Control Function IMS: IP Multimedia Subsystem

MGW

SGSN

MGW

GGSN

UTRAN

MSCserver

GMSCserver

PSHSS

PSTN

IP networ

k

MRF

CSCF

MGCF

IMS

Data & Control

Control

Instead MSC (MSS)

Instead GMSC

Instead HLR

AUC

GERAN

EIR

IMSMGW

CS

Evolution of UMTS Core (Release 4-)


Node B (Base Station) Channel coding and interleaving,

spreading/despreading) modulation/demodulation, rate adaption, radio measurements, etc.)

RRM (Radio Resource Functions): softer handover, closed loop power regulation

RNC (Radio Network Controller) Contols the interface functions between UMTS

radio interface and Core Network Controls RRM-Radio Resource Management, like

soft and hard handover, outer loop power regulation

Controls protokolls between: UE-RNC, RNC-RNC and RNC-MSC/SGSN

Load Management, Admission Control

Tasks of UTRAN Elements


CBC: Text Message Service for all users in the cell (without addressing)

SMLC : Handles and Contols Location Based Services

RNCCell Broadcast Centre (CBC)

Iu-BC

Serving Mobile Location

Centre(SMLC)

Iu-PC

New Network Elements in UMTS


MSC, GMSC server Controls signalling functions One MSC, GMCS server controls several MGWs

MGW (Media Gateway) Controls and Swithes Circuit switched connectionsHSS (Home Subsciber Server) Instead HLR (mobility management, security functions,

authentication, etc.)MRF (Media Resource Function) Handles and contols multimedia connections and resources

CSCF (Call Session Control Function) Sets up and controls voice connections (Voice over IP)

MGCF (Media Gateway Control Function) Controls gateway functions between IP Multimedia

Subsystem (IMS) and other networks (eg. Internet)

Network Elements in 3G Core Network


RRM features Dimanic channel allocation, spectrum

capacity handling Guaranteed QoS parameters for users Channel optimization for cell Capacity optimization for channels

RRM control functions Power control Handover Admission control Load control

Radio Recource Management (RRM)


GSM antennas

Adjustable antennas

Directional Antennas


Omni antenna mounted on mobile tower

„Handy” omni antenna

Omni antennas


Micro antennas: connections towards the core network (some ten GHz)

Microwave Antennas


MIMO antennas (LTE)

Multiple sector

antennas in the same cell

3G/4G Antennas


Indoor Antennas (examples)


Channel Capacity

C - channel capacity [bit/s]B - channel bandwidth [Hz]S - signal power [W]N - noise power [W] (Caused by the interferences)

- If we want to keep the same S/N for a channel, and we want to increase the datarate, we must to increase the bandwith.

- If the interference (Noise) is high, S/N is decreasing, channel capacity is also decreasing.

B

C

N

S

N

SBC

N

SBC

2ln

2ln1log2

Hartlay-Shannon law:


In CDMA networks:

1. If the number of UEs the level of interference is also ▪ Each UE causes interference:

▪ For other UEs in the cell▪ For other UEs in adjacent cells

…………means the capacity of cell is

2. If the output power of UE the interference is also

…………means the capacity of cell is

Importance and Necessity of Power Control


Power control:minimalizálni kell az interferenciát hogy a kapacitást növelni lehessen

UE2UE1

Node B• The accurate and fast

power control is one of the main factors of the capacity efficiency of WCDMA networks

• If the output power of UE is too high, it can block the traffic of other UE in the given cell and adjacent cells too

Near-far problem

Power Control (near-far problem)


UMTS-ben alkalmazott háromféle teljesítmény-szabályozás megoldás:

Open loop Fast inner closed loop Slow outer closed loop

Types of Power Control


Used, when UE wants to attach to a cell (uplink)Tolerance: ± 9-12 dB (path loss, slow fading)

When uplink connection starts, the closed loop power control begins

Node BUE

Downlink power measurement (BCH)

Tx power

Open-loop Power Control


Uplink Node B measures BER and calculates SIR (Signal to

Interference Ratio) If SIRmeasured> SIRtarget Node B regulates UE to decrease the

output power Ha SIRmeasured< SIRtarget Node B regulates UE to increase the

output power

Speed of regulation = 1500/s at each UE (accuracy: average 1dB)▪ In GSM-ben slow power contol is used (2 Hz)▪ The process is very fast, ensures good channel quality

The high output power of UE causes interference in the cell

Downlink No near-far problem Node B power depends on the traffic and required QoS in

the cell

UE2

UE1

Node B

Tx telj. Tx telj.

Fast Closed-loop Power Control (UE-Node B)


SIRtarget depends on channel FER and traffic in the cell and adjacent cellsSIRtarget depends on speed of UE (BER is changing in UL).

Outer loop between NodeB and RNC SIRtarget is changing, its value is increasing or decreasing

continuously depending on the traffic (number of Ues and QoS)

RNC(Outer loop control)

Node B(Inner loop control)

UE

FER

SIRtarget

SIRtarget

Time

Outer Loop Power Control


Handover: Channel or cell reselection procedure during a connection (speech or data)

Types: Hard handover

Frequency change in the same system: used in WCDMA system between different carrier bands (FDD1-FDD2 or FDD-TDD)Frequency band change because of system is changed (intersystem handover): UMTS-GSM , UMTS-LTE

Soft handover: Between two Node Bs

Softer handover: Between two sectors of one Node B

Types of Handover


MS or UE connects only one BTS/Node B at the same time

MS/UE changes carrier frequency during handover! BTS 1

(f1,TS5)

BTS 2 BTS 1

(f2,TS3)

BTS 2

MSa

MSa

GSM

UMTS

f2

f1 f1

f2

UMTS

GSM

Hard Handover in GSM and UMTS


Used in WCDMA systems

Soft handover One UE is connected to more Node Bs at the same time

UE communicates with NodeB2 and NodeB1 parallely „Seamless” handover between cells (no frequency

reallocation)

Multiple connection to NodeBs is called→ Macro-diverzity

Soft Handover

Node B1Node B2

1

UEa Node B1

Node B2

2

UEa

Node B1

Node B2

UEa

Node B3


UE communicates at the border of the sectors of two Node Bs

UE-Node Bs communicaton on different radio channels in parallel, channel combination is required

Two power control loops are active

Szektor 1

Szektor 2

RNCNode B1

UEa

Node B2

Soft Handover


UE communicates on the border of two sectors of one Node B

UE-Node B communicaton on two different radio channels Channel combination (uplink) by Node B

One power contol loop is active

Sector 1

Sector 2

RNCNode B

UEa

Softer Handover


Hard HandoverBTS1 – BTS1

BTS1 - BTS2

- GSM/GPRS-Discontinuity in the connection

Soft handover Node B1 - Node B2 - cdma2000, UMTS- No discontinuity in the connection

Softer handover Node B1 - Node B1 - UMTS

Frekvencia hard handover

Carrier f1 - Carrier f2 - UMTS

Rendszer hard handover

Network1 –Network2 - WCDMA FDD / GSM

Handover Review


Frequency Hopping (fast, slow) Direct Sequence (DS)

- Simple implementation - Good channel and bandwidth efficiency - cdma2000, WCDMA

Time Hopping Multi Carrier systems (OFDM) Combined systems

Spead Spectrum Solutions


A B AB

0 0 0

0 1 1

1 0 1

1 1 0

Spreading – one information bit is multiplied by a spreading code sequence Spreadind code bits = chips Number of bits/information bits = Spreading Factor (SF= 4,

8, 16, …512)

A B AB

+1 +1 +1

+1 -1 -1

-1 +1 -1

-1 -1 +1

XOR

100 kb/s (or kchip)

10 kb/s 100 kbpsInformation bits

Spreading code

sequence

Spreaded info

XOR logical function and its analog signals

Direct Sequence Spreading


Information bits at the trasmitter

Spreading sequence (SF = 8)

Information on the channel

Spreading

Spreading sequenceDespreading

Information at the receiver

Information bit (0)

Chip

1-1

1-1

1-1

1-1

1-1

Synchronization is required

Theory of Spreading/Despreading (sample)


Despreading causes a processing gain on the channel

The spectum power density is increasing at the receiver output

Processing gain: PG

PGSNRin SNRout(dB) = SNRin(dB) + PG(dB)

Despreading

Signal to Noise Ratio on the

receiver input

Signal to Noise Ratio after

despreading

Processing Gain


][log10 10 dBR

RP

R

RP

Info

PNG

Info

PNG

RPN – chip rate RInfo – information bit rate

Example:RPN = 3,84 McpsRInfo = 12,2 kbps

PG = 10*log10(3,84*106/12,2*103) = 25 dB

After despeading, the signal power must be some dB more than the noise power, otherwise the channel information can be lost at the receiver.

Calculation of Processing Gain


Two channels with different datarates:

Example:

1.) RPN = 3,84 Mcps 2.) RPN = 3,84 Mcps RInfo = 12,2 kbps (speech) RInfo = 2 Mbps (data) PG = 25 dB PG = 2,8 dB

Let we suppose: SNRout = 7 dB is requred

SNRout = SNRin + PG 1.) SNRIN = SNROUT - PG = -18 dB 2.) SNRIN = SNROUT - PG = 4,2 dB

Conclusion: Speech channel needs lower output power at the transmitter than fast rate data channelImportance of power regulation!

Processing Gain and Transmitter Output Power


twAtctstctstctsS cnnTx cos)]()(...)()()()([ 2211

Channels are modulated on the same frequency band

Channels have different spreading codes (C1-Cn) Information bit rates are different (speech, data)

c1(t)

s1(t)

c2(t)

s2(t)

cn(t)

sn(t)

∑

Acos(ωct)

f(Hz)

Signal power

f(Hz)

f(Hz)

f(Hz)

f(Hz)

f(Hz)

f(Hz)

Power

STXPseudo-noise 1

Pseudo-noise 2

Pseudo-noise 3

Background noise

Signal power

Signal power

Modulator

Spreading

DS-CDMA Channel Multiplexing

Signal power

Signal power

Signal power


1)()(,1)()(cos)()()(cos])()()([)()(

)(cos)]()(...)()()()([)()(

111'

111'

211

1'

22111

tctctctctwAtctctstwAtctctstctS

tctwAtctstctstctstctS

icc

n

iiiRx

cnnRx

f(Hz)

Signal at the receiver

fc = c/2

c1(t)

fc = c/2

Narrow band filter

The received signal is a sum of all channels on

radio inreface

Despreading means a XOR logical function between channel info and channel (Wlash) code

SRX

Unwanted signal (interference) Wanted signal

All channels on radio interface

Demodulator

DS-CDMA Despreading


Natural and artificial objects cause reflections , diffractions, attenuation on the radio channels because of multipath propagation

The reflected signals arrive in different times to the receiver The changes of signal power density gives the profile of the

multipath propagation Delay:

1-2 µs in urban, suburban environment Some 10 µs in highways, roads, rural environment

Multipath components

Multipath Propagation


Tchip = 0,26 µs (WCDMA, 3,84 Mc/s)

Két eset: Ha TMultiCom 0,26 µs, a vevő szét tudja választani és

kombinálni a többutas komponenseket hogy meghatározza a jel diverzitását ▪ TMultiCom ≥ 0,26 µs …ha az átviteli út ≥ 78 m

(kis mozgási/chip sebesség)▪ 1 Mc/s esetén, 300 m

Általában több egyforma hosszúságú terjedési út van adott idő alatt

Például a /2 (2GHz, =15 cm), késleltetéssel érkező jelek egy chipidő késleltetéssel érkeznek a vevőre

Ha az adó mozog jelvesztés vagy gyors fading jelentkezhet a kioltások miatt.

TMultiCom

Többutas terjedés problémája


The received signal power is decreasing 20-30 dB suddenly

Rayleigh distribution fading

Solutions in WCDMA systemsRake receiverFast, closed loop power controlEfficient coding shames, interleaving, ARQ procedures

Fast Fading Problems


Determination of received signals Determination of fingers on the same channel (peak power

density of the same signal) Same chips are received with different power density and in

different times because of multipath propagation

Characterization Fingers are characterized by vectors (phasors), with their

amplitudes and phase Changes ≤ 1 ms Signal Processing 3-4 consecutive fingers are processed in the receiver Rake receiver

CDMA Receiver


Theory: Maximal Radio Combining (MRC) WCDMA systems use pilot signals, for channel estimation Compensation of delay is needed The fingers are added after compansation

Finger 1

Finger 2

Finger 3

Signal of transmitt

er

Fingers with

different delays

After delay compensation

Summed phasors

Σ

Phase compensation

Evaluation of Fingers


Finger 3

Correlator and code generator: despreads de channel signalsChannel estimator: estimates the channel from pilot signalsPhase rotator: rotates the finger’s phase to the original (regarding the pilot)Phase equalizer: equalizes the different phases of fingersAdder: adds compensated signalsFilter: filters fingers from the channel

Incoming signal Ad

de

r

Finger 2

Finger 1

Correlator

Code generator

Channelestimation

Phase rotator

Phase compensation

Filter

De

co

de

r

Időzítés

CDMA Rake Receiver (with 3 fingers)


Problems: Interference between channels Random cell load

Features: Auto-correlation Cross-correlation

Types of codes: PN (Pseudo random Noise) sequence

▪ MLS (Maximal Length Sequence) Gold code Walsh code

WCDMA Codes


dttFtFACF

)()( ACF in the case of time dependent, continuous signal

NCCCCACF ACF for bit sequences (discrete signals): → Comparition of the bit sequence with its shifted version (shift: 1-L)

# Same bits

# Different bits

ACF: Auto-Correlation Function

Definition of Auto- Colleration


-2

0

2

4

6

8

Shift (bits) Bit sequence CC NCC ACF

0 1011100 7 0 7

1 0111001 3 4 -1

2 1110010 3 4 -1

3 1100101 3 4 -1

4 1001011 3 4 -1

5 0010111 3 4 -1

6 0101110 3 4 -1

7 1011100 7 0 7

Kor

relá

ció

PN shift04 05 06 00 01 02 03 04 05 06 00 01 02 03

Calculation of Auto-correlation (example)


dttGtFCCF

)()(

Time dependent F(t) és G(t) CCF

NCCCCCCF CCF for two different bit sequence → comparition of two sequence

# Same bits

# Different bits

Ortogonal codes: CCF = 0

CCF: Cross-Correlation Function

Definition of Cross-Correlation


1... 1111 xaxaxaxP nnnn

123 xxxP

12 NL

7123 L

PN sequence – binary bit sequence with pszeudorandom features … PN sequence is not determinstic but fully random…

PN generator Linear Feedback Shift Regiszter (LFSR) Polinomal presentation:

Length of PN sequence:

x0 x1 x2 x3

clockPN sequence

[chipek] … N – number of D laches

Example: Shift register with 3 D laches

PN (Pseudo Noise) Sequence


Gold code: Two PN sequnce are added by modulo 2 adder (XOR) (primitive expression)

By shifting one PN sequence we get different GOLD codes

Simple auto-correlation is zero Helps asynchron transmission: A lot of codes can be generated with good

correlation

Gold Codes


NN

NNN MM

MMM 2

Walsh codes:Differents codes in the same matrix are orthogal

(CCF = 0)Bad auto-correlation

Walsh matrix:▪ n x n matrix▪ Matrix description: (m = size of matrix, i = )

1001

0011

0101

1111

0110

1100

1010

00000110

1100

1010

0000

0110

1100

1010

0000

0110

1100

1010

0000

10

000 8421 MMMM

miW 8

1W

10101010

Walsh Codes


01 W

0020 W

001142 W

0121 W

010141 W 01104

3 W

0000000080 W 000011118

4 W 0011001182 W 010101018

1 W 0011110086 W 010110108

5 W 0110011083 W 011010018

7 W

ismétlés& invertálás

ismétlés

000040 W

Walsh Code - Tree Presentation


Codes Chips Analog signals

Walsh 0 0000

Walsh 1 0101

Walsh 2 0011

Walsh 3 0110

bit 0 ≈ +1bit 1 ≈ -1

Walsh code 3

bit 0 bit 1

User bits

Walsh 3

After spreading

A user (Walsh 0)

B user (Walsh 2)

C user (Walsh 3)

0

0

0

0

0

1

0

1

0

0

1

1

1

1

1

+3,+1,-1,+1

Walsh Codes- Spreading (example)


14

4 1

4

4

1

4

4

A user (Walsh 0) 0 0 0 0 1

B user (Walsh 2) 0 0 1 1 1

C user (Walsh 3) 0 1 0 1 1

A (Walsh 0)

Walsh code * spreaded infoNumber of chips

14

4

Information bits (A user) 0 0 0 0 1

CCF=1*3+1*1+1*(-1)+1*1

14

4

Walsh Codes - Despreading


Codes System Advantages Disadvantages

Walsh UMTS, cdmaOne • Codes are orthognal

• bad auto- and cross corretation

PN sorozat cdmaOne

• Good auto correlation

• Non orthogonal codes• Bad cross correlation • Small number of codes

Gold UMTS • Good cross correlation• Great number of codes•Auto correlation Walsh < Gold < PN sorozat

• non orthogonal codes

Correlation features determine the interference in the cells

WCDMA capacity depends on the level of interference

Codes - Review


User dataSi

Chanellization kód(Walsh)

Signal rate (changing)

Chip rate (fix)

Spreading Codes= Walsh codes One channel one code Different channelization in UL and DL The length of code is changing (4-512)

Ci

Ci+1

Si+1

Ck

Sk

UMTS Codes –Transmitter (I.)


Scrambling: the spreaded information is multiplied by a scrambling code

Used after speading The datarate does not change Scrambling codes: Identifies Node Bs (each Node B has different scrambling codes) Autocorrelation of a channel is better

Scrambling (Gold)

Chip rate

User infoSi

Channelization kód(Walsh)

Signal rate (changing)

Chip rate (fix)

Ci

Ci+1

Si+1

Ck

Sk

UMTS Codes in Downlink


Chanellisation code Walsh code Separates data and control physical channels

Scrambling code Short (Gold code) vagy long (PN sequence) Separates Users (UE)

There is no synchronization between UE’s channels in Uplink!

UMTS Codes in Uplink


Spreading/Chanellization codes Scrambling Codes

HasználatDownlink: separates Ues in the cellUplink: separates the control and data physical channels from UE

Downlink: Separates Node BsUplink: Separates Ues in the cell

Number of chips

Downlink: 4-512 chip

Uplink: 4-256 chip

Downlink: 10 ms = 38400 chips Uplink: 10 ms = 38400 chips or 66,7 µs = 256 chips

Number of codes

Given number in UL and DL applicationDownlink: 512Uplink: some billions

Bandwidth Megnöveli az átviteli sávszélességet Nincs hatása a sávszélességre

UMTS Codes Summary

dr. dóra maros. korszerű mobil rendszerek evolution of communication

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