Download Towards Wireless Overlay Network Architectures

Beyond Third Generation Cellular:
Convergence of Internet and Cellular Infrastructure
Technologies
MSC
BSC
VLR
HLR
AUC
EIR
GSM Core
(IP-Based)
GW
Proxy
Server
Next
Generation
Internet
HA
FA
BS
GW
Corporate
Intranetwork
Randy H. Katz and Reiner Ludwig1
Computer Science Division, EECS Department
University of California, Berkeley, CA 94720-1776
on assignment from Ericsson Radio Systems ERA/T/N
1
The Two Hottest Trends in
Telecommunications Networks
700
600
Millions
Mobile Telephone
Users
500
400
Internet Users
300
200
100
0
1993 1994 1995 1996 1997 1998 1999 2000 2001
Year
Source: Ericsson Radio Systems, Inc.
Background
• 1st generation: analog cellular
• 2nd generation: digital cellular
• 3rd generation: multiple, heterogeneous access
technologies (WLAN, cellular, satellite)
– GSM cellular evolution: data support, higher bandwidth
» HSCSD, GPRS, W-CDMA (Ericsson and Nokia)
– Core cellular network: evolving towards a combined circuit
and packet switching infrastructure
• 4th generation:
– Eliminate circuit switching through “next generation
Internet” integration: voice (and video) over data
– New services: voice-data integration w/ multipoint
capabilities, intelligent location-aware & “follow me”
mobility, push-based information dissemination, ...
3rd Generation Access Technologies
Wired
Mbps
100
10
1
Wireless
Local Area
Networks
60 GHz
100 m range
“Mobile Broadband
Systems”
Cordless
“Universal Mobile
Telecomms Systems”
(UMTS)
0.1
Cellular
0.01
Office or
Room
Building
Indoors
Stationary
Walking
Outdoors
Vehicle
Trends
• Multimedia over IP networks
– Next Generation Internet with features for “soft” QoS
– RSVP, Class-based Queuing, Link Scheduling
• Voice over IP networks
– Packet Voice and Video
– RTP and ALF
• Intelligence shifts to the network edges
– Better, more agile software-based voice and video codecs
• Programmable intelligence inside the network
– Proxy servers intermixed with switching infrastructure
– TACC model & Java code: “write once, run anywhere”
Implications for cellular network infrastructure of
the 21st century?
Issues
• Scalability
– Must scale to support hundreds of thousands of simultaneous
users in a region the size of the SF Bay Area
• Functionality
– Computer-phone integration
– Real-time, multipoint/multicast, location-aware services, security
– Home networking, “active” spaces, sensors/actuators
• First Principles-based Design
– Leverage evolving IP traffic models
– Provisioning the network for the extrapolated traffic and services
– ProActive Infrastructure
» Computing resources spread among switching infrastructure
» Computationally intensive services: e.g., voice-to-text
» Service and server discovery
Current Vision of 3rd Generation Cellular
PSTN
ISDN
Circuit-Sw itched
64 kbit/s trunks
Internet
Direct IP-Access
for CS Data
CS-based
"core-GSM
network"
SS7-based
Signalling
GSM BSS
Circuit-Sw itched
Voice
Circuit-Sw itched
Data (HSCSD)
GPRS IP-Backbone
UMTS BSS
Packet-Sw itched
Data (GPRS)
3rd Generation Radio
Circuit-Switching (CS)
Paket-Switching /
IP-Routing
Vision for Beyond 3rd Generation Cellular
PSTN
ISDN
CS / IP
Gatew ay
Internet
High Bandw idth
Trunks
IP-based
"core-GSM
network"
IP-Sw itching
Backbone
Mobile-IP & RSVPbased Signalling
Voice & Data
ov er IP ov er GPRS
GSM BSS
QoS Support
in GPRS
IP-Multicast
Proxies
(Security, Transcoding)
UMTS BSS
3rd Generation Radio
Project
Vision
• How far can we go
with a packetswitched cellular
core network?
• How do you
provision an IP
network for large
numbers of voice
users?
• What new kinds of
data-oriented
services can be
deployed?
ProActive Infrastructure
Source
Sink
Server
Router
Compute
Node
• Computing resources
inside the routing topology,
not just at the leaves
• Paths chosen for location
of operators as much as for
shortest # of hops
• Mobile code that
specializes the services
provided by servers
• Focus on mobility,
management of bottleneck
links, “integration”
services
Project Areas
• Mobility Management
• Packet Scheduling in GPRS and W-CDMA
• Proxy- and Multicast-Enabled Services
Mobility Management
• Mobile IP-GSM Mobility Interworking
– Mobile IP-GSM authentication interworking
– Scalability of Mobile IP/hierarchical agents
• Multicast support for mobility
– Alternative approach for mobility based on M/C addresses
– Exploit multicast routing to reach mobile nodes without explicit
handoff
– Combine with real-time delivery of voice and video
• Generalized redirection agents
– Policy-based redirection: e.g., 1-800 service, email to pagers, etc.
– Redirection agents collocated with multicast tree branching
points
Packet Scheduling
• Validated ns modeling suite for GSM media
access, link layer, routing, and transport layers
– GSM channel error models
• QoS-aware High Speed Circuit Switched Data
(HSCSD), General Packet Radio System
(GPRS), and Wideband CDMA (W-CDMA) link
scheduling
–
–
–
–
RSVP signaling integration with bottleneck link scheduling
Fairness and utilization for TCP and RTP flows
Delay bound scheduling for R/T streams
Exploiting asymmetries in downstream/upstream slot
assignment, CDMA self-interference
New Services
• Proxies for Telephony-Computing Integration
– GSM-vat-RTP interworking: handset-computer integration
– Encapsulating complex data transformations
» Speech-to-text, text-to-speech
– Composition of services
» Voice mail-to-email, email-to-voice mail
– Location-aware information services
» E.g., traffic reports
– Multicast-enabled information services
» Multilayered multicast: increasing level of detail as
number of subscribed layers increase
Project Strategy
GSM Infrastructure Elements
-- Data over PBMS GSM Network
-- GSM Base Station
-- Integration with IP-infrastructure
Analyze
Existing Systems
Prototype Elements
Design
-- Handset/computer integration
-- Java-enabled components
-- ProActive infrastructure
Next
Generation
ns Simulations
-- Ericsson channel error models
-- GSM-based infrastructure
-- GSM media access & link layer
Implement
New System
Project Schedule
• Year 1: 1998
– ns modeling, validation
– GSM BTS-IP integration
– Initial design of mobility interworking and intelligent
networking services
• Year 2: 1999
– GSM-Wireless LAN integration
– Design of information-push applications
– Implement mobility interworking
• Year 3: 2000
– Extend testbed with W-CDMA and GPRS
– Roaming, scheduling, new applications demonstrations
– Fine-tuning and documentation