Wireless WANs: From 1G to 4G Module W.wanxue-gt/wireless/Online Course... · 1 Wireless WANs: From 1G to 4G Module W.wan.2 Dr.M.Y.Wu@CSE Shanghai Jiaotong University Shanghai, China

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Wireless WANs: From 1G to 4GModule W.wan.2

Dr.M.Y.Wu@CSEShanghai Jiaotong University

Shanghai, China

Dr.W.Shu@ECEUniversity of New Mexico

Albuquerque, NM, USA

© by Dr.Wu@SJTU & Dr.Shu@UNM

W.wan.2-2

Wireless WAN: 1G 4G1G

AMPS2G

GSMCase Study: GSM & cdmaOne (W.wan.3)

2.5G3G

Case Study: UMTS/W-CDMA (W.wan.4)4GEnd of module W.wan.2


W.wan.2-3

Cellular network, 1G

Analog-basedEuropean: NMT (Nordic Mobile Telephony)USA: AMPS (Advanced Mobile Phone Service), AT&T 1980s

two 25-MHz bands allocated to AMPSFrequency reuse N=7, R = 2-20 km, K = 30KHzEach band split into two service providers A & B to encourage competition

12.5 M / 30 K = 416 channels395 voice channels, FM/FDD21 control data channels, FSK, 10 kbps

An AMPS cell phone includes a NAM (Numeric Assignment Module)= telephone number + 32-bit serial number from manufacture

B: 12.5 MHz downlink

A: 12.5 MHz downlink

B: 12.5 MHz uplink

A: 12.5 MHz, uplink,

869-894 MHz824-849 MHz


W.wan.2-4


Analog-based, USA: AMPS (Advanced Mobile Phone Service)

Initial setup operationsMT power on, scan for the most powerful control channel, broadcast its NAM; BS hears MT’s NAM, registers with MSC (Mobile Switching Center)MT updates its location every 15 minutes

Making a call# to be called via access channel: MT BS MSCMSC schedule/assign up/down links’ channels

Answering a callMT is alerted to incoming call via a paging channel

Power savingPeriodically sleep for 46.3 ms, then scan for paging channel

Designed for GoS (Grade of service) of 2% blocking


W.wan.2-5

Cellular network, 1G 2G

From 1G to 2G1G

Analog-basedFrequency modulationDeveloped for a single application: voiceOther services, such as fax, data, were defined as overlay services on top of the analog voice service

2G Digital-basedTDMA & CDMAIntegrated voice/data servicesprovide encryption to prevent eavesdroppingError detection and correction, giving clear voice receptionAllow channels to be dynamically shared by a number of users


W.wan.2-6


AMPS2G


2.5G3G



W.wan.2-7

GSM cellular network, 2G

GSM (Global System for Mobile communications), 1991R = 100m - 35 km, K = 200 KHzIntegrated services with three domains:

Call forwarding, conference call up to 7, call-back

Supplementary services

Circuit or packet switching: asynchronous data, (up to 9600 bps), synchronous (2.4, 4.8, 9.6 kbps)

Bearer services

Telephone (13 kbps voice), emergency calls, SMS (short message service, 160 chars), FAX

Teleservices

ServiceService Category


W.wan.2-8

GSM physical layer, 2G

Frequency bands: 890-915 MHz (uplink), 935-960MHz (downlink), Europe1800 MHz, DCN (Digital Communication Network)1900 MHz, USA450 MHz, replacing analog NMT system

K = 200 KHz, duplex channels are separated by 45 MHz(25 M – 2x100KHz guard band) / 200 K = 124 channels

Each 200 KHz 270.8 kbpsEach 200 KHz channel has 8 TDMA slots

Each with 0.577 ms duration270.8/8 = 34 kbps + FEC 9.6 kbps

Modulation: GMSK (Gaussian minimum shift keying)


W.wan.2-9

GSM frames & channels, 2GFDMA/TDMA; frames & bursts

1 2 3 4 5 6 7 8

higher GSM frame structures

935-960 MHz124 channels (200 kHz), downlink

890-915 MHz124 channels (200 kHz), uplinkfre

quen

cy

time

GSM TDMA frame

GSM time-slot (normal burst)

4.615 ms

546.5 µs577 µs

tail user data TrainingSguardspace S user data tail guard

space3 bits 57 bits 26 bits 57 bits1 1 3


W.wan.2-10

GSM frames & channels, 2GTraffic for every 20 ms

Logically 4 burstsevery 24 bursts of traffic, adding 2 bursts of control(4 x 4.615ms) x (26/24) = 20ms

Overhead addedApplication bits + coding payloadPayload + guarding & training trafficTraffic + control physical carrier

33.8 kbps22.8 kbpsvoice: 13 kbpsdata: 9.6 kbps

Bandwidth

624456voice: 260data: 244

Bits

TrafficPayloadApplication


W.wan.2-11

GSM frames & channels, 2GAlignment of downlink & uplink

If a MT receives data in time t on the downlinkit access on the uplink at time t+3x.577msso it does not need a full-duplex transmitter

GSM logical channels = TCHs + CCHsTraffic channels (TCHs)

Full-rate traffic channel (TCH/F), 22 kbps13 kbps speech-coding voice traffic9.6 or 4.8 or 2.4 kbps data traffic

Half-rate traffic channel (TCH/H)4.8 kbps voice traffic4.8 or 2.4 kbps data traffic


W.wan.2-12

GSM frames & channels, 2GGSM logical channels = TCHs + CCHs

Control channels (CCHs)BCCH (Broadcast control channel, downlink broadcast),

Synchronization, frequency control, BS’s ID & channel status

DCCH (Dedicated control channel, two way)Call setup, location updates, call managementEvery call has its own allocated DCCH

CCCH (Common control channel, one way)Downlink, paging channel for BS to alert MT for incoming callUplink, random access channel for MT to initiate a new callDownlink, access grant channel for BS to inform MT of an allotted duplex channel for a call


W.wan.2-13

Other cellular network, 2G

D-AMPS (Digital AMPS), USACoexist with AMPS, also known as IS-54Use AMPS carriers to deploy digital channels

TDMA, six slots per frame

cdmaOne, South Korea & Hong Kong, 1993; USA, 1996Also known as IS-95 (telecommunication Industry association interim Standard)Fully digital standard, in 800 MHzOnly 2G CDMA, supports 4.8 & 14.4 kbps

PDC (Personal digital cellular), JapanBased on D-AMPS


W.wan.2-14

Cellular markets, 2G

USAVerizon

CDMA and analogT-mobile

GSMSprint PCS

CDMACingular

GSM, TDMA, analogChina

移动

联通


W.wan.2-15


AMPS2G


2.5G3G



W.wan.2-16

Cellular network, 2.5GData services over GSM

SMS (Short Message Service)Each up to 160 characters in lengthMessage transfer takes place over the control channel

HSCSD (High-Speed Circuit-Switched Data)Circuit-switched protocol for larger file transfer & multimediaOccupies up to eight TDMA clots per user

If using 4 slots, 57.6 kbpsAsymmetrical, usually downlink demands more

Increases blocking probability; Not efficient for burst data due to connection oriented protocol. Also, being charged by time not data.


W.wan.2-17

Cellular network, 2.5G

Data services over GSM GPRS (General Packet Radio Service)

TCP/IP packet service, no end-to-end connectionUse all eight slots, up to 171.2 kbps (depending on coding scheme)Allow for broadcast, multicast, and unicastBeing charged on volume instead of on connection time

Always on, no connection setupAll time slots can be shared by the active users, up and down links are allocated separately

On-demand scheduling, using idle time slots onlyRequire more addition of infrastructureCan also be used for other TDMA systemsExtended infrastructure for UMTS (3G)


W.wan.2-18

Cellular network, 2.5G

Data services over GSM EDGE (Enhanced Data Rates for GSM Evolution)

Also known as EGPRS (Enhanced GPRS)Instead of the binary GMSK, it uses 8-PSK modulation to triple the capacity compared to GSM, but more susceptible to errorsHave 9 different modulation & coding schemes, each designed for a different quality conditionUtilizing 200KHz narrow-band to approach 3G services

Data services over AMPSCDPD (Cellular Digital Packet Data)

Connectionless data packet serviceBe able to detect idle voice channels to transmit data packetsContinuously hop channels without blocking a voice call


W.wan.2-19


AMPS2G


2.5G3G



W.wan.2-20

Cellular network, 2G 3GUniform and continuous presentation of services, independent of location and access

Aim at providing a virtual home environmentDemand intelligent network to retrieval and update location information, handle handoffs, etc

Evolution plan: 2G 3G

China

W-CDMA (DoCoMo)PDCJapan

cdma2000UWC-136

cdmaOne/IS-95IS-136

USA

W-CDMA (UMTS)GSMEurope

3G StandardExisting 2GCountry


W.wan.2-21

IMT-2000: cellular network, 3GIMT-2000 (International Mobile Telecommunications)

The system would become available in the year of 2000Has data rates of 2000 kbpsOperate in the 2000 MHz region

Very nice, but dream didn’t come true

circuittelephone28.8 kbps28.8 kbpsSpeech

packetemail28.8 kbps28.8 kbpsSimple messaging

CircuitFax43.2 kbps43.2 kbpsSwitched data

PacketWeb 768 kbps19.2 kbpsMedium multimedia

PacketTV2 mbps20 kbpsHigh multimedia

CircuitVideo conf256 kbps256 kbpsInteractive Multimedia

SwitchingExampleDownstreamUpstreamService


W.wan.2-22

IMT-2000: cellular network, 3GEnabling technology for 3G

Smart antennasControl a directional array with an advanced digital signal processing capability

CDMACan operate in the presence of interferenceSupport very large bandwidthIn practice, some disappointing performance

Spectrum allocationIMT-2000 specified 2GHz spectrum could not be implemented

Were partially or fully in use in many countries


W.wan.2-23

IMT-2000: cellular network, 3G

IMT-2000

1850 1900 1950 2000 2050 2100 2150 2200 MHz

MSS↑

ITU allocation(WRC 1992)

IMT-2000MSS↓

Europe

China

Japan

NorthAmerica

UTRAFDD ↑

UTRAFDD ↓

TDD

TDD

MSS↑

MSS↓

DECT

GSM1800

1850 1900 1950 2000 2050 2100 2150 2200 MHz

IMT-2000 MSS↑

IMT-2000MSS↓

GSM1800

cdma2000W-CDMA

MSS↓

MSS↓

MSS↑

MSS↑

cdma2000W-CDMAPHS

PCS rsv.

Frequencies planned by IMT-2000Original: 1885-2025 (140MHz), 2110-2200 (90MHz)

Including two 30MHz MSS (Mobile Satellite Services)New addition: 800-1000, 1700-1900, 2500-2700 MHz


W.wan.2-24


Europe, W-CDMA (Wideband CDMA)Also known as UMTS (Universal Mobile Telecommunication System)

CDMA-based

Wideband K = 5 MHz (That is “W” meant, in GSM, K=200KHz)

Interwork with GSM, handoff between WCDMA cell & GSM cell

USA, cdma2000An extension of cdmaOne

UWC-136TDMA-based, an upgrade of IS-136 (2G)

Watch out for new progress… http://www.3gpp.org


W.wan.2-25

Cellular network, 3G 4GDream of 4G in year of 2010?

Seamless integration with wired IP networksHigh bandwidth, up to 100 mbpsUbiquityHigh-quality multimedia servicesAdaptive resource managementSoftware-defined radio to make handsets efficient and flexible

Programming functionalityModulationCodingMAC protocol

Reconfigurable and extendable


W.wan.2-26


AMPS2G


2.5G3G

Case Study: UMTS/W-CDMA (W.wan.4)4GEnd of module W.wan.2WLL & 802.16: module W.wan.5

Documents

Wireless WANs: From 1G to 4G Module W.wanxue-gt/wireless/Online Course... · 1 Wireless WANs: From 1G to 4G Module W.wan.2 Dr.M.Y.Wu@CSE Shanghai Jiaotong University Shanghai, China