iBurst Mobile BroadbandUTS – Faculty of Information Technology

Jonathan Withers

CTO – Personal Broadband Australia

jonathan.withers@pba.com.au

27 April 2005Mobile Broadband

www.iburst.com.au

2

Broadband Definitions

• Broadband

– India: >128 kbps

– Korea: >2 Mbps

– Australia: 256kbps or >512 kbps?

• Broadband creates sense of immediacy:

– Always on

– Quick Response

Broadband = speed + availability + low latency

This is what users want

3

Pre-requisites for Wireless Broadband

• Must deliver the speed (> 512 kbit/s per user)

• Must deliver immediacy => low latency

• Ubiquitous coverage

• ‘Portability’ essential, ‘Mobility’ highly desirable

• Easy integration with existing systems and applications

• Network economics that allow large quantities of data to be carried at reasonable rates

4

The iBurst Broadband Service

High speed:

– 1 Mbit/s/user downlink

– 345 kbit/s/user uplink

• Low latency

– Approx. 50 mS

• Always on

• Secure

• Guaranteed packet delivery

• Mobile or fixed use

• Standard IP devices, apps

• Affordable, attractive

• Sydney, Melbourne, Brisbane, Canberra, Gold Coast

IP Networks

5

Laptop, PDA, Home or Network

•Mobile connectivity• PCMCIA card• Connect to Laptop or PDA• Unrestricted mobility• 1 Mbps / 345 kbps speed• Low power consumption

• Tx 21 dBm max• Sleep mode

• Fixed/Portable connectivity• Desktop connectivity• Network connectivity• Ethernet or USB• 1 Mbps / 345 kbps speed

• Tx 25 dBm

6

Network Coverage

• Up to 10 km from one base station (typ. 3-5 km)

• Cover high density areas where targeted business users work and live:– CBDs– Airport Corridors– Inner City (businesses and high value

residential areas)– Residential Suburbs

• Expand coverage:– Technology Parks– Outer Residential Areas– New Residential Developments

• Replicate deployment methodology for all Capital cities and expand to other major towns

7

The Wireless Broadband Challenge

$0.10$1.37Price/MB

22 MB/mo.

300 minutes

typically ~10 kbps

$30/mo.

Cellular Voice

300 MB/mo.Typical consumption

Unlimited access at typically ~500 kbps

Package

$30/mo.Subscriber price

Wired Broadband

Example

Figure

s

Example

Figure

s

Requires fundamental advances in operator

economics — i.e. multiples of current range & capacity

8

Data Pricing – Network Cost Driven

$0.30$0.10$0.03$0.01

100K

200K

300K

400K

500K

1MB

2MB

3MB

$1.00 $2.00

50K

$5.00Cost per megabyte

Access speed

narrowband

broadband

speed

threshold

price

threshold

$10.00

Fixed

broadband systems• Primarily data access• Efficient• Priced in megabytes

Cellular systems• Primarily voice access• High cost for data• Priced in kilobytes

Data economics Mobile economics

9

Access Landscape

Fixed Local area Wide area

Broadband

Narrowband

Speed

2G

2.5G

3G

Mobility

Wi-Fi &

hot spots

Bluetooth

Dialup

Fibre

Microwave

Cable/DSL

Satellite

NarrowbandNarrowband

BroadbandBroadband

256 kbit/s

Mobility + Speed

Network finds userUser finds network

10

What Drives Wireless Economics?

• Total cost to deliver a quantum of data to a unit area (e.g. Mbit/s/sq km):

– Cost of Spectrum

• Type of spectrum and rights of use are important

– Density of Base Stations required• Coverage & capacity capability of technology are key

– Cost of Backhaul & site rentals

– Cost of Equipment

• Especially the user terminal device

11

The Radio Reality

• Radio is a challenging medium:

– Very lossy: 150dB path loss in just a few kms.

– Corruption due to fading, multipath and interference.

– Hard to predict exact performance at any location

– Needs to be protected against unlawful interception

• But, it is the way to provide untethered communications – it’s the way we want to operate

Have to find a way…

12

Solving the Engineering Challenge

• Problem: Bandwidth delivered ∝ power received

– To deliver 1 Mbps requires 10x more received power than to deliver 100 kbps

– Receivers & coding near ‘state-of-art’ - only fractional improvements possible

• Solution: Re-visit radio propagation fundamentals– Use latest DSP/algorithms to exploit each user’s unique spatial identity

– ‘Spot light’ user rather than ‘Flood light’ them

– Dramatic improvements to coverage and spectrum efficiency (capacity)

• Result: � Winning Wireless Broadband Business Case

– Increased coverage

– Higher per user data rates

– Ample capacity

– Reduction in base station density & associated costs

13

Technical Advantages of iBurst

The Key Differentiator is the Radio design:

1. Smart Antenna (Intellicell) technology developed by ArrayComm Inc. provides superior Range and Speed Capability

2. Capacity (highest spectral efficiency of all competing systems)

3. Standard IP Transport (IP ‘Pipe’ through the Air)

4. Simple User Terminal

(‘smarts’ reside in network)

All these factors result in compelling network economics

14

• Results in:

– Improved Path Loss Capability:

• Signals up to 100x stronger - improved coverage and building penetration

• Increased user data rates possible

– Energy directed only to User

• Better spectrum use (greater capacity, reduced interference)

Adaptive Antenna TechnologyFundamental to Improved Link Budget

‘Broadcast’ Approach Adaptive Transmission

15

Spatial ChannelsSupporting Two or more Users on the Same Channel

• Spatial channels allow communication with two or more people at the same time on the same frequency in the same cell.

• Frequency Re-use drops below 1

• Spectral efficiency multiplies accordingly; 2 users = 1/2, 3 users=1/3

16

Conventional Systems• Limited cell size• Different cells use different channels• Limited per-cell capacity (due to interference)

Adaptive Antenna Systems• Expanded cell size• All cells use all channels• Dynamically managed interferencegives maximum per-cell capacity

• Spectrum can be used over and over

iBurst: Coverage and Capacity Benefits

17

iBurst Conceptual Architecture

Client Application

User Terminals

Radio Base Station Network

Transmission Network Core Network

Customer ISPs

Desktop PC

I-Burst Wireless Modem

Ethernet or USB

Connection

Laptop

I-Burst PCMCIA

I-Burst Base Station

L2 Switch

I-Burst Base Station

L2 Switch

TransmissionNetwork

GRE Tunnels; Ethernet over

SDH

Radius

PDSN

L2 Switch

L2 Switch

Email

Internet

VPN

Router

RouterLNS

LNS

Radius

Radius

Air Interface

Air Interface

Ethernet

Client Application

User Terminals

Radio Base Station Network

Transmission Network Core Network

Customer ISPs

Desktop PC

I-Burst Wireless Modem

Ethernet or USB

Connection

Laptop

I-Burst PCMCIA

I-Burst Base Station

L2 Switch

I-Burst Base Station

L2 Switch

TransmissionNetwork

GRE Tunnels; Ethernet over

SDH

Radius

PDSN

L2 Switch

L2 Switch

Email

Internet

VPN

Router

RouterLNS

LNS

Radius

Radius

Air Interface

Air Interface

Client Application

User Terminals

Radio Base Station Network

Transmission Network Core Network

Customer ISPs

Desktop PC

I-Burst Wireless Modem

Ethernet or USB

Connection

Laptop

I-Burst PCMCIA

I-Burst Base Station

L2 Switch

I-Burst Base Station

L2 Switch

TransmissionNetwork

GRE Tunnels; Ethernet over

SDH

Radius

PDSN

L2 Switch

L2 Switch

Email

Internet

VPN

Router

RouterLNS

LNS

Radius

Radius

Air Interface

Air Interface

Ethernet

18

iBurst Security Benefits

• iBurst provides advanced security mechanisms:– Mutual authentication of UTs and BSs on the radio link

– Encryption for privacy of user data on the radio link

• Uses Digital Certificates for fast, low-latency operations involving only local communication

• Encryption uses RC-4 stream cipher with up to 280 bit key

• Architected to overcome known security attacks

• Standards-based

• Immune to known Wi-Fi attacks

• Supports end-to-end security solutions at Layers 3 and up

• iBurst security mechanisms have been independently reviewed by industry experts and confidentiality verified

19

Base Station Authentication : i-HAP

• User Terminals communicate only with authorized iBurst Base Station

• Public key crypto based authentication

• RSA signatures, Elliptic curve cryptography

User Terminal Authentication : i-TAP

• Each Base Station authenticates User Terminal using public key based protocol

• Prevents session theft at handover

• Digital certificates periodically updated

Symmetric key bulk encryption: i-SEC

• Encrypts both user and control data over the air interface

• Up to 280 bit secret key

• Set dynamically on each session

iBurst-specific Security Mechanisms

20

Summary: iBurst Security

IPBack-haul Transport

CA

LDAP,RADIUS

ServicesPDSN

Air-interfaceEncryption

BS AuthenticationKey Exchange

Key ExchangeUT authentication

i-SEC

i-TAP, i-HAP

i-TAP, i-HAP

i-TAP, i-HAP Digital certificates in User Terminals and Base Stations ensure high air interface security without involvement of core network components

Standard security mechanisms such as CHAP, IPSec, SSL transparently supported

21

Challenges Facing Wireless Data

• Air Interface IP Transport Efficiency:– How to best transport a mix of voice and data

– Inefficiencies of VoIP

– Packet prioritization, managing latency

• Protocols to handle time-varying channel characteristics

– Delivery of streamed services

– Management of temporary coverage outages

– Performance of ‘LAN based’ legacy protocols with latency

• Implementation of Multicast alongside P2P Traffic