PCS Mobile Commu

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September 30, 2005 Girish Kumar Patnaik 1

What is PCS?

Personal Communication Services


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What is PCS

Personal Communication Services

A wide variety of network services that

includes wireless access and personal mobility

services

Provided through a small terminal Enables communication at any time, at any

place, and in any terminal form.


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Several PCS systems

High-tier Systems

Widespread vehicular and pedestrian services

GSM: Global System for Mobile Communications

The mobile telephony system that we are using

IS-136

USA digital cellular mobile telephony system

TDMA based multiple access

Personal Digital Cellular

IS-95 cdmaOne System

CDMA based multiple access


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Several PCS systems

Low-tier systems

Residential, business and public cordless access

applications and systems

Cordless Telephone 2 (CT2)

Digital Enhanced Cordless Telephone (DECT) Personal Access Communication Systems (PACS)

Personal Handy Telephone System (PHS)


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Several PCS systems

Wideband wireless systems

For Internet access and multimedia transfer

Cdma2000, evolved from cdmaOne

W-CDMA, proposed by Europe

SCDMA, proposed by Chine/Europe


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Several PCS systems

Other PCS Systems

Special data systems

CDPD: Cellular Digital Packet Data

RAM Mobile Data

Advanced Radio Data Information System (ARDIS)

Paging Systems Mobile Satellite Systems

LEO, MEO, GEO satellites for data/voice

ISM (Industrial, Scientific and Medical) band systems:Bluetooth, 802.11, etc.


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PCS Problems

How to integrate mobile and wireless users

to the Public Switched Telephone Network

(PSTN) (Voice Network) Cellular mobile telephony system

How to integrate mobile and wireless usersto the Internet (Data Network)

Mobile IP, DHCP, Cellular IP

How to integrate all of them together and

also add multimedia services (3G Systems)


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InternetPSTN(Telephone Network)

Looking to PCS from different

Angles

Wireless Access

Mobile Users

-Laptop users-Pocket PC users-Mobile IP, DHCP enabledcomputers

Mobile Users

-Cell phone users-Cordless phone users

Telecom People View Data Networking People ViewSeptember 30, 2005 Girish Kumar Patnaik 8


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Telecom and Data Networking

Telecom Interest Data Networking Interest

-Radio Propagation-Link Characteristics-Error Models-Wireless MediumAccess (MAC)- Error Control

-Data Transmission

-Mobile IP (integratingmobile hosts tointernet)-Ad-hoc Networks-TCP over Wireless-Service Discovery

- Voice Transmission- Frequency Reuse

- HandoffManagement-Location Tracking-Roaming-QoS-GSM, CDMA,Cordless Phones,-GPRS, EDGE


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Very Basic Cellular/PCS Architecture

Base Station(BS) Mobile Station

MobilityDatabase

Mobile

SwitchingCenter(MSC)

Base StationController

Radio Network

Public Switched

Telephone Network


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Wireless System Definitions

Mobile Station A station in the cellular radio service intended for use

while in motion at unspecified locations. They can beeither hand-held personal units (portables) or installed on

vehicles (mobiles)

Base station A fixed station in a mobile radio system used for radio

communication with the mobile stations. Base stations are

located at the center or edge of a coverage region. They

consists of radio channels and transmitter and receiverantennas mounted on top of a tower.


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Mobile Switching Center Switching center which coordinates the routing of calls in

a large service area. In a cellular radio system, the MSCconnects the cellular base stations and the mobiles to thePSTN (telephone network). It is also called MobileTelephone Switching Office (MTSO)

Subscriber A user who pays subscription charges for using a mobile

communication system

Transceiver A device capable of simultaneously transmitting and

receiving radio signals


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Control Channel Radio channel used for transmission of call setup, call

request, call initiation and other beacon and control

purposes.

Forward Channel

Radio channel used for transmission of information fromthe base station to the mobile

Reverse Channel

Radio channel used for transmission of information frommobile to base station


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Simplex Systems Communication systems which provide only one-way

communication

Half Duplex Systems Communication Systems which allow two-way

communication by using the same radio channel for bothtransmission and reception. At any given time, the usercan either transmit or receive information.

Full Duplex Systems

Communication systems which allow simultaneous two-way communication. Transmission and reception istypically on two different channels (FDD).


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Handoff The process of transferring a mobile station from one

channel or base station to an other.

Roaming A mobile station which operates in a service area (market)

other than that from which service has been subscribed.

Page A brief message which is broadcast over the entire service

area, usually in simulcast fashion by many base stations atthe same time.


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PCS Architecture


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PCS Architecture

Each PCS technology has similar architectures

which consists two parts

Radio Network

MS (Mobile Station)

BS (Base Station) System

Wireline Transport Network

MSC (Mobile Switching Center)

The Mobility Database connected to MSC is used totrack the locations of mobile station.


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PCS Systems Classification

Cellular Telephony (High-tier)

Cordless Telephony and Low-Tier PCS 3G Wireless Systems


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Cellular Telephony

Characterized by

High mobility provision

Wide-range

Two-way tether less voice communication

Handoff and roaming support Integrated with sophisticated public switched

telephone network (PSTN)

High transmit power requires at the handsets

(~2W)


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Cellular Telephony - Architecture

Radio tower

PSTN

Telephone

Network

Mobile Switching

Center


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Cellular Telephony Systems

Mobile users and handsets

Very complex circuitry and design

Base stations Provides gateway functionality between

wireless and wireline links

Mobile switching centers

Connect cellular system to the terrestrial

telephone network

C ll l N t k


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Cellular Networks First Generation

Analog Systems Analog Modulation, mostly FM

AMPS

Voice Traffic

FDMA/FDD multiple access Second Generation (2G)

Digital Systems

Digital Modulation

Voice Traffic

TDMA/FDD and CDMA/FDD multiple access

2.5G Digital Systems

Voice + Low-datarate Data

Third Generation Digital

Voice + High-datarate Data

Multimedia Transmission also

Ad d M bil Ph S i


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Advanced Mobile Phone Services

(AMPS) Analog FM radio for voice transmission

FSK modulation for signal channels FDMA

FDD

Total 50 MHz=824-849 MHz(down-link) + 869-894MHz(up-link)

832 full-duplex channels using 1664 discrete frequencies

Downlink: from base station to handset

Uplink: from handset to base station

30 KHz spacing

Ad d M bil Ph S i


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Advanced Mobile Phone Services

(AMPS) Frequency reuse scheme for radio communication

Cells are grouped into clusters Cells within a cluster must use different frequencies

Frequencies may be reused by cells in different clusters

In AMPS 12-cell cluster using omni-directional antennas

7-cell cluster using three sectors per BS

EIA/TIA IS-41 standard for roaming management.

Global S stem for Mobile


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Global System for Mobile

Communication (GSM)

Digital cellular system

TDMA/FDD

935-960 MHz for Downlink

890-915 MHz for Uplink

200 kHz for RF channel spacing

Speech coding rate 13 Kbps



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Communication (GSM)

Frequency carrier is divided into 8 time slots

Every pair of radio transceiver-receiver supports 8 voice

channels.

GSM Mobile Application Part (MAP) for roamingmanagement

Digital switch can provide many applications:

Example: point-to-point short messaging, group addressing,call waiting, multiparty services

EIA/TIA IS 136 Digital Cellular


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EIA/TIA IS-136 Digital Cellular

System Digital AMPS (DAMPS), American Digital Cellular(ADC), or North American TDMA (NA-TDMA), IS-

136 The successor to IS-54

TDMA/FDD

Every frequency carrier supports three voice channels

Speech coding rate is 7.95Kbps

The same spectrum used by AMPS 3 times of capacity of AMPS

30 KHz frequency spacing



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System

2 types of channel usage:

Full-rate: use 2 timeslot for a voice channel

Half-rate: use 1 timeslot for a voice channel

Digital switch can provide many applications: Example: point-to-point short messaging, broadcast

messaging, group addressing, private user groups

IS-41 standard for mobility management



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System CDMA/DSSS for the air interface.

A shared 1.25 MHz channel bandwidth User signals distinguished with different codes

MSs links to many BSs during phone calls.

GPS for synchronization of BSs Interference-based capacity (soft capacity)

The capacity of IS-95 is 3-6 times of IS-136 system, and 10

times of AMPS. IS-41 for core network

Advanced Radio Resource Management


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Cordless Telephones

PSTNTelephone

NetworkBase unitCordlessPhone


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Cordless Telephones

Characterized by

Low mobility (in terms of range and speed)

Low power consumption Two-way tetherless (wireless) voice communication

High circuit quality

Low cost equipment, small form factor and long talk-time

No handoffs between base units

Appeared as analog devices Digital devices appeared later with CT2, DECT

standards in Europe and ISM band technologies in

USA

Cordless Telephone Second


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Cordless Telephone, Second

Generation (CT2) Developed in Europe, available since 1989.

40 FDMA channels 32-Kbps speech coding rate

TDD

The maximum transmit power of a CT2 handset is 10mW

No handoff in CT2 No call delivery in CT2

In CT2+, both handoff and call delivery are OK.

Digital European Cordless


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Digital European Cordless

Telephone (DECT) Published in 1992

TDMA/TDD

12 voice channels per frequency carrier

Sleep mode is employed in DECT to conserve the power ofhandsets.

32 Kbps speech coding rate DECT is typically implemented as a wireless- PBX (Private

Branch Exchange) connected to the PSTN.

Dynamic channel allocation Time slot transfer

Seamless handoff

Dual mode: DECT + GSM

Low-Tier PCS: Personal Handy


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ow e CS: e so a a dy

Phone System (PHS) Developed by Research and Development Center (RCR), Japan 1993

Offers telecommunication services for homes,offices, and outdoor environment

TDMA/TDD

4 multiplexed channels/frequency carrier

1895-1906.1 MHz = 300 KHz 37 channels

(home/office) 1906.1-1918.1 MHz = 300 KHz 40 channels

(public system)

32 Kbps speech speech coding rate

Low-Tier PCS: Personal Access


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Communications System (PACS) Developed at Telcordia, U.S.A. PACS is designed for wireless local loop and

Personal Communications Services.

TDMA

8 voice channels/frequency carrier Both TDD and FDD are accommodated.

The highly effective and reliable mobile controlledhandoff (MCHO) completes in less than 20 msec.


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3G Systems

Goals

Voice and Data Transmission

Simultanous voice and data access

Multi-megabit Internet access

Interactive web sessions Voice-activated calls

Multimedia Content

Live music

Third-Generation Wireless


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Third Generation Wireless

Systems First Generation System: AMPS

Analog voice calls

Second Generation Systems: GSM, IS-136, IS-95,

and low-tier systems

Digital speech with low-bit-rate data services

Third-Generation:

Better system capacity

High-speed and wireless Internet access (to 2Mbps)

Wireless multimedia services (audio and video)

Third-Generation Wireless


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Third Generation Wireless

Systems 2.5G: GPRS and EDGE

Bridge 2G into 3G The new features for 3G includes

High bit rates, QoS, Bit rates dependent ondistance

Asynchronous Transfer Mode (ATM) backbone

Wideband CDMA (DS-CDMA FDD), SCDMAand cdma2000 (multi-carrier FDD) for air

interface


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GSM and CDMA Coverage Map

Worldwide


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Acknowledgement

Slides obtained from home page of

Prof.Phone Lin

Slides obtained from home page of

Prof.Gerald Q. Maguire Jr.

Documents

PCS Mobile Commu