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3G Tutorial
Brough Turner & Marc Orange
Preface...
The authors would like to acknowledgement material contributions from:
Murtaza Amiji, NMS Communications
Samuel S. May, Senior Research Analyst, US Bancorp Piper Jaffray
Others as noted on specific slides
We intend ongoing improvements to this tutorial and solicit your comments at:
rbt[at]nmss.com
and/or marc_orange[at]nmss.com
For the latest version go to:
http://nmscommunications3Gtutorial
1G — Separate Frequencies
2G — TDMATime Division Multiple Access
2G & 3G — CDMACode Division Multiple Access
Spread spectrum modulation
Originally developed for the military
Resists jamming and many kinds of interference
Coded modulation hidden from those w/o the code
All users share same (large) block of spectrum
One for one frequency reuse
Soft handoffs possible
Almost all accepted 3G radio standards are based on CDMA
CDMA2000, W-CDMA and TD-SCDMA
Multi-Access Radio Techniques
3GPP2 Defines IS-41 Evolution
3rd Generation Partnership Project “Two”
Separate organization, as 3GPP closely tied to GSM and UMTS
Goal of ultimate merger (3GPP + 3GPP2) remains
Evolution of IS-41 to “all IP” more direct but not any faster
Skips ATM stage
1xRTT — IP packet support (like GPRS)
1xEVDV — adds softswitch/ voice gateways
3x — triples radio data rates
2G cdmaOne (IS-95 + IS-41)
CDMA2000 1x Network
Packet Data Serving Node (PDSN)
Establish, maintain, and terminate PPP sessions with mobile station
Support simple and mobile IP services
Act as mobile IP Foreign Agent for visiting mobile station
Handle authentication, authorization, and accounting (AAA) for mobile station
Uses RADIUS protocol
Route packets between mobile stations and external packet data networks
Collect usage data and forward to AAA server
1xEVDO — IP Data Only
1XEVDV — IP Data and Voice
3G Tutorial
Up and Coming Mobile Services
SMS, EMS, MMS
Location-based services
3G-324M Video
VoIP w/o QoS; Push-to-Talk
IP Multimedia Services (w/ QoS)
Converged “All IP” networks — the Vision
Short Message Service (SMS)
Point-to-point, short, text message service
Messages over signaling channel (MAP or IS-41)
SMSC stores-and-forwards SMSs; delivery reports
SME is any data terminal or Mobile Station
SMS Principles
Basic services
SM MT (Mobile Terminated)
SM MO (Mobile Originated)
(3GPP2) SM MO can be cancelled
(3GPP2) User can acknowledge
SM Service Center (3GPP) akaMessage Center (3GPP2)
Relays and store-and-forwards SMSs
Payload of up to 140 bytes, but
Can be compressed (MS-to-MS)
And/or segmented in several SMs
SMS Transport
Delivery / Submission report
Optional in 3GPP2
Messages-Waiting
SC informs HLR/VLR that a message could not be delivered to MS
Alert-SC
HLR informs SC that the MS is again ready to receive
All messages over signaling channels
Usually SS7; SMSC may have IP option
Location
Driven by e911 requirements in US
FCC mandated; not yet functioning as desired
Most operators are operating under “waivers”
Potential revenue from location-based services
Several technical approaches
In network technologies (measurements at cell sites)
Handset technologies
Network-assisted handset approaches
Plus additional core network infrastructure
Location computation and mobile location servers
Significant privacy issues
Location Technology
Cell identity: crude but available today
Based on timing
TA: Timing Advance (distance from GSM BTS)
Based on timing and triangulation
TOA: Time of Arrival
TDOA: Time Difference of Arrival
EOTD: Enhanced Observed Time Difference
AOA: Angle of Arrival
Based on satellite navigation systems
GPS: Global Positioning System
A-GPS: Assisted GPS
Location-Based Services
Emergency services
E911 - Enhanced 911
Value-added personal services
friend finder, directions
Commercial services
coupons or offers from nearby stores
Network internal
Traffic & coverage measurements
Lawful intercept extensions
law enforcement locates suspect
Location Information
Location (in 3D), speed and direction
with timestamp
Accuracy of measurement
Response time
a QoS measure
Security & Privacy
authorized clients
secure info exchange
privacy control by user and/or operator
US E911 Phase II Architecture
3G QoS
Substantial new requirements on the radio access network
Traffic classes
Conversational, streaming, interactive, background
Ability to specify
Traffic handling priority
Allocation/retention priority
Error rates (bits and/ or SDUs)
Transfer delay
Data rates (maximum and guaranteed)
Deliver in order (Y/N)