Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 1

Communication Networks 1

Principles of Mobile Communications

University Duisburg-EssenOct., 2003

N e v e r s t o p t h i n k i n g .

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 2

Principles of Mobile Communications

Written by: Prof. Dr.-Ing. Andreas Czylwik

Hold by: Dr.-Ing. Christian Kranz

Supported by: Dipl.-Ing. Lars Häring

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 3

2.4GHz ISM Band

! Basic Books:– T.S. Rappaport: Wireless Communications, Prentice Hall– G.S. Stüber: Principles of mobile communications, Kluwer Academic

Publishers– W.C. Jakes: Microwave mobile communications, John Wiley– K. David, T. Benkner: Digitale Mobilfunksysteme, Teubner-Verlag

! Advanced Books:– H. Meyr, M. Moeneclaey, S.A. Fechtel: Digital Communication

Receivers, Wiley Series in Telecommunications– J.D. Parsons: The mobile radio propagation channel, John Wiley– J. Eberspächter, H.-J. Vögel: GSM - Global system for mobile

communication, Teubner Verlag– H.Holma, A. Toskala: WCDMA for UMTS, John Wiley– S. Blume: Theorie elektromagnetischer Felder, Hüthig

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 4

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 5

Principles of Mobile CommunicationsThe Electromagnetic Spectrum

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 6

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 7

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 8

Cellular and Local Systems in the World

Systems in „free“ ISM (Industrial Sience

Medical)bands

Systems incommercial, licensed, reserved frequency

bands

WLANGSM UMTS BluetoothCDMA

2000 Zigbee

IS-95 DECT WDCTpropriety

Home-RF

WiMedia

∆

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 9

Important Cellular Systems (European)

http://www.gsmworld.com

System / Net GSM-900 GSM-1800 GSM-1900 W-CDMA UMTS TD-CDMA UMTS

Frequency890-915 (up), 935-960MHz

1710-1785 (up), 1805-1880MHz

1850-1910 (up) 1930-1990MHz

1920-1980 (up) / 2110-2170MHz

1900-1920 / 2010-2025MHz

System Bandwidth 25MHz (x2) 75MHz (x2) 60MHz (x2) 60MHz (x2) 20/15MHz

Duplex Method FDD (45MHz) FDD (95MHz) FDD (80MHz) FDD (120MHz) TDD

Access Method FDMA/TDMA FDMA/TDMA FDMA/TDMA FDMA/CDMA FDMA/TDMA

Modulation GFSK, BT=0.3 GFSK, BT=0.3 GFSK, BT=0.3 QPSK QPSK

Channel bandwidh 200kHz 200kHz 200kHz 5MHz 5MHz

Datarate 9,6...171,2kbit/s 9,6...171,2kbit/s 9,6...171,2kbit/s 16...384kbit/s (1,92MBit/s) up to 2Mbps

Mobility 250km/h 130km/h 130km/h 300km/h

MS-Power 13...33dBm 4...30dBm 4..30dBm 21...33dBm 21...33dBm

Distance ca. 10km ca. 8km ca. 8km ca. 10km indoor

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 10

Important Systems in Licensed & ISM Bands

System / Netcordless

phone DECTWPAN

Bluetooth V1.2WPAN Zigbee

802.15.4WLAN

802.11bWLAN

802.11a

Frequency [MHz]

1880-1900 (licensed DECT

only) 2400-2483.5

2400-2483.5 902-928

868-868.6 2401-2483

5150-5250 5250-5350 5725-5825

System Bandwidth 20MHz 83.5MHz 83,5MHz 200MHzDuplex Method TDD TDD TDD TDD TDD

Access Method FDMA/TDMAFHMA (FHSS)

1600Hops/s CSMA/CA CSMA/CA CSMA/CA

Modulation GFSK, BT=0.5 GFSK, BT=0.2x

O-QPSK BPSK BPSK

DBPSK DQPSK QPSD

OFDM with BPSK, QPSK, 16-QAM, 64-

QAM

Channel bandwidh 1728kHz 1MHz

5MHz 2MHz

300kHz 22MHz

Datarate 1152kBit/s1Mbit/s

(724kbit/s)250kBit/s

40kBit/s 20kBit/s1MBit/s - 11MBit/s

6MBit/s - 54MBit/s

network peer to peer 7 slaves piconet255 (65535)

slaves piconet LAN LAN

MS-Power 24dBm 20dBm local regulations

16dBm 23dBm 29dBm

Distance 300m 10m-100m - 100m 100m

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 11

Piconet Example from 802.15.3 - WiMedia

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 12

multipath fading inurban area

small scale fading

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 13

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 14

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 15

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 16

e.g. DECT cordless phones (10 frequencies, 24 time slots)

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 17

e.g. Bluetooth (79 frequencies, 1600hops/s)

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 18

adaptive beamforming

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 19

WLAN: Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)

Multiple Access Medium:• It is possible that more than one transmitter wants to start transmission at the same time• A collision destroys the actual data packet normally

Transmitter

Receiver

Mediumin use

DIFS

Data Packet

Backoff

ACK

SIFS DIFS

time

Random timeintervall, differentat each accessor

CSMA/CA (distributed coordination function, DCF):• Each transmitter checks the medium before starting transmission• If a running transmission is detected the transmitter waits until its end + DIFS + Backoff• The Backoff time is a random time different at each transmitter with adaptive range• Control packets have higher priority (SIFS is shorter than DIFS, no Backoff)

DIFS: Distributed Inter Frame Space, all assessor of the medium have to wait this time before starting backoffSIFS: Short Inter Frame Space, used if it is clear which station is allowed to transmits next (e.g. ACK)ACK: Acknowledge

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 20

WLAN - Wireless Local Area Networks - OverviewWLAN802.11

IR FHSS1MBit/s

DSSS2MBit/s

802.11a5.15 - 5.35 GHz

6/9/12/18/24/36/48/54MBit/s(CCK-OFDM)

802.11b2.40-2.48 GHz

1/2/5.5/11MBit/s(DSSS)

802.11g2.40-2.48 GHz

1/2/5.5/11/6/9/12/18/24/36/48/54MBit/s

802.11hTCP: Transmit Power ControlDCS/DFS: Dynamic Channel

Dynamic FrequencySelection

IOP-Standards:Wi-Fi (www.wi-fi.org)

Intel centrino

EuropeanReglementations

802.11e(QoS)

EDCF, HCF, AIFS

FHSS: Frequency Hopping Spread SpectrumDSSS: Direct Sequence Spread SpectrumCCK-OFDM: Complimentary Code Keying Orthogonal Frequency Division Multiplexing

EDCF: Enhanced Distributed Coordination FunctionHCF: Hybrid Distribution FunctionAIFS: Arbitration Inter Frame Space

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 21

Broadcast Channels (BCH’s)

in TS0 of a cell specific ARFCN

• Broadcast Control Channel

• Frequency Correction Channel

• Synchronization Channel

200k

Hz wide

ARFCNs pairs

(abso

lute r

adio

frequ

ency

chan

nel n

umbe

r)

8 TS’s (time slot)

mobile is always

synchronized

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 22

Trainings Sequence:

channel estimation

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 23

Upgrade Path for 2G to 3G technologies

W-CDMAUMTS

TD-CDMAUMTSTD-SCDMA

Global System Mobile (GSM)

Interim Standard 95 (IS-95, cdmaOne)

IS-136 (north americandigital cellular–NADC)

& PDC (parcific digital cellular) Japan

China

cdma2000 1xRTT

3GPP3GPP2

cdma20001xEV

cdma20003xRTT

www.3gpp.org www.3gpp2.org

2G

GPRS

2.5GHSCSD IS-95BEDGE

3G

3GPP (3rd generation partnerchip project) Source: T.S. Rappaport, Wireless Communications, Prentice Hall

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 24

Evolution for 2.5G TDMA Standards for GSM

" HSCDS (High Speed Circuit Switched Data)

# use of consecutive user time slots in the GSM system

# relaxes the error coding algorithm (9.6kbps -> 14.4kbps)

# up to four consecutive time slots (-> 57.6kbps)

# ideal for streaming internet

# not an „always on“ access to the network

# requires new handsets

# only software change in existing GSM base stages

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 25

Evolution for 2.5G TDMA Standards for GSM

" GPRS (General Packet Radio Service)

# packet based data network for non real time internet usage

# much more download than upload capability

# multi-user network, sharing the time slot and data channel

# uses dedicated GSM channels, with „always on“ access to network

# same modulation scheme than original GSM but new air interface

# max. data rate (all 8 GSM radio channels are dedicated to GPRS)171.2kbps (8x21.4kbps) of raw uncoded data throughput

# error correction moved to the higher protocol layer

# new packet overlay at Infrastructure (router gateways)

# new GPRS handsets required

# since end of 2001 the most popular near-term packet data solution

Dr.-Ing. Ch. KranzSMS IC CE DlfAug. 25, 2003Page 26

Evolution for 2.5G TDMA Standards for GSM

" EDGE (Enhanced Data rates for GSM Evolution)# new digital modulation format 8-PSK (octal phase shift keying) in addition to

GSM’s standard GMSK

# 9 different (autonomously and rapidly selectable) air interface formats - multiple Modulation and Coding Schemes MCS

# Each MCS state can use GMSK or 8-PSK

# The coverage range is reduced for the higher data rates MCS

# a famliy of MCSs is used for each GSM radio channel time slot (incremental redundancy, start with safest MCS and reduce protection and increase/decrease data rate until the link is unacceptable)

# use always minimum amount of overhead for each user

# raw peak data rate (single user) 547.2kbps, practical limit is 384kbps

# combining several radio channels (multi carrier) EDGE can provide several megabits per second