Communications Inc

Public Emergency Alerts Over Cellular Phones

…The Challenges

Gyles Panther6 November 2003

Basic Alerts, Requirements

•Primary Notification (Alert)

•Instruction / Direction

•Calm and Inform

•Interactive Management

•Situation Analysis

Basic Alerts, Suitability

•Primary Notification (Alert)

•Instruction / Direction

•Calm and Inform

•People Management

•Situation Analysis

4

The Issues

• What constitutes Wireless

• Addressing Geographical Regions

• Network Issues (Carrier)

• Alerting Issues (Alertee)

• HandSet Issues (Phone)

• Implementation

5

Wireless Networks

• Cellular- GSM / TDMA / CDMA / IDEN

• Paging- One Way (POCSAG / FLEX)- Two Way (REFLEX / Data Networks)

• Data Networks- Mobitex / Ardis

• New cellular data capabilites- GPRS, 1xRTT

• Chosen Focus is Cellular

6

Short History of Cellular (3)

GPRS(170/60)*

(kb/s)

EDGE(384/144)*

(kb/s)

IS-136(TDMA)

North America

AMPSPrimarily

North America

GSMTDMAEurope

IS-95A(CDMA)

North America

IS-95B(CDMA)1xRTT

(144/60)*kb/s)

CDMA2000(CDMA)

1x/3xRTT(2Mb/144)*

kb/s)

W-CDMA(UMPTS)

(2000/144)*Mb/s)

1stGeneration

2ndGeneration

"2.5"Generation

3rdGeneration

"*" indicates Maximum/usable data rates

"IMT2000"

7

Normal (Voice) communications

• Network : locates handset by registration

• Control channel sets up comms

• Single phone Address i.e. One to One

• Cannot address One to Many

• No intrinsic mapping of cells to location

• Cells variable in size

8

Alert Transmissions

• Address ALL, i.e. Broadcast

• Registration irrelevant

• Geographical Address

• Alert Message Transmitted Digitally

• Message Content :- Displayed Text ( Language? )- Spoken ( Language?)

- Displayed ( Video +Speech, language? )

9

Data Over Wireless

• GSMGPRS…Packet data service 170kb/s raw; 40kb/s Usable ? EDGE…Enhanced GSM packet data 384kb/s raw; 60kb/s Usable?UMTS…3G Packet data service: 2Mb/s raw; 144kb/s Usable?

• CDMA1xRTT…Basic CDMA packet: 144kb/s raw; 60kb/s Usable?3xRTT…Enhanced CDMA packet, 2Mb/s raw; 144kb/s Usable?

• IDEN(?)

10

Existing Message Service

• e.g. SMS- Implemented by all carriers- Interoperable between carriers- Text Messages- Approximately 160 Character limitation

• EMS, MMS- Large data files- spooled voice- photographic Picture quality (needs display!)

• but….– All are Point to Point

11

GSM- Cell Broadcast

• Cell Specific BroadcastsPoint to MultipointShort messages, limited to 15 * 93 Characters (SMS-CB)Up to 64k CB “Channels”

• Optional ETSI Standard (1993)Software upgrade to GSM networkNot widely implementedLimited / no commercial payback.

• “Cell Broadcast Forum”Standardized handset requirementsUser Opt IN-OUT service selectionSMS-CB can trigger data “pull” ( via WAP )

12

Geographic Addressability

• Return path for 2-Way devices inherentlyrequires network location

• Cellular handsets continuously located through“registration” process

• Supposition of network geography on networklocation

• Geographic resolution depends on cell size,likely poor

13

Cell Broadcast – Limitations

• Cell Resolution is variable, – Network to network, – Place to Place

Roads

WantedCoverage

Region

Cell CoverageCarrier 'A'

Cell CoverageCarrier 'B'

Populated Region(Village)

FictitiousExample

14

Selective Area Reception

• Assuming………- A broadcast capability, regional or wide area- A population of network assisted GPS handsets…

• A Broadcast alert message with…. - “Network assist” GPS data- “Geographic Address” (targeted area)- Emergency alert Message- Enunciation control data- Plus control fields…

• Phones located in Geographic address respond…

15

Handset Function

• Special Alert- Display Standardized Message

- Streaming Audio File

• Probably amenable to commerce

• Cellular networks now data “pipes”

• Alert / Handset function

- Through Network definitions (eg CAB) ?

- Through Handset Software ?

16

Limitations and Liabilities

• Some Handsets will miss alerts:- Poor local coverage- Handset in use

• Handset use while driving banned some places• Warned user might consult display while driving

- Injury may result- Who owns legal liability?

• Much preferred to send voiced message- text to voice, or- Streaming audio file

17

A CAS System

• A CAS Server application- Highly reliable, Redundant architecture

- Authentication on Clients, direct users

• Message Gateway to each carrier

• Client population- Generator sites (Police, EMO, Environmental Agencies)

- GUI / GIS capability

- Overlay of Sensitive Sites

- Authentication of Users (generators)

18

A Cellular Alert System

Internet

Carrier 'A'

CAS ApplicationServer

Location 2

CAS ClientWeather (eg)

CAS ClientPolice, location 'a'

PSTN

Carrier 'A' Gateway

Carrier 'C'Gateway

Tx Tx

Cell Site

Data

Cell Site

Tx Tx

Data

Cell Site

Tx Tx

Data

Firewall&

Server

TrunckedRadio

PSTN

CASClientEnvironment

Carrier 'B'Gateway

Firewall&

Server

ReliableFrameRelay

CAS ApplicationServer

Location 1

Carrier 'B'

Carrier 'C'

ReliableInternet

Connectios

Distributed EmergencyAlert Contributors

EmergencyAlert Servers

19

Implementation

• Cell Broadcast Alerts- Now available GSM, Coming for CDMA- less than Ideal system could be built- Limited system, Patented

• Selective Area Reception- New Message Types- Handset software required- Better System, no patents

• Funding- Commercial Applications ?- Subsidies ?

20

Implementation

• Neither Do-able on Present Networks• CAB requires:

- CAB Network Implementation (Expensive?)- Public take-up of CAB capable phones- Network development (Geo overlay on Network Topology)

• SAR requires:- Extensive lobbying of specifying entities- New system message types (broadcast)- New generation of handsets/handset software

• Implementation must be International

21

Implementation

• Government -Industry group to define- Method of selective area access- Broadcast Message spec- CSAAC network requirements

• CAS system Design- Server system and Application S/W- Client Application Software

• CAS administrative functions- System management, Training, public awareness,

22

Challenges (1)

• 5 year horizon may require mandate

• Formation of common intent

• Complex service behaviour– Through Handset Software?– Through Network Standards?

• Agree on CAS method– Cell location– Selective Area Reception (GPS)

• Commercial Applications– Traffic, Geo-referenced Advertising

23

Thank You

Gyles Panther

Wi-Sys Communications Inc.

308 Legget Drive,

Ottawa, Ontario

K2K 1Y6

www.wi-sys.com

Communications Inc