AN EXPERIMENTAL
PERFORMANCE COMPARISON OF
3G AND WI-FI
Richard Gass (Intel Labs Pittsburgh)
Christophe Diot (Technicolor)
OUTLINE
20100408
Motivation
 3G vs. Wi-Fi Face-off Experiments
 Results
 Conclusions

PAM 2010 Zurich
2
THE FUTURE OF MOBILE COMMUNICATIONS
20100408
Number of mobile devices is increasing per user
 Many useful mobile apps require the use of
Internet services
 Consumption of data is ever increasing

PAM 2010 Zurich
Users are straining service providers
 Service providers are straining users (cost)

3
SATISFYING CONNECTIVITY DEMANDS
20100408

Dominant technologies
3G (mobile)
 Wi-Fi (stationary)

PAM 2010 Zurich

3G
Large coverage areas
 Seamless connectivity
 Current applications work
 Data rates are low

~386Kbits/s-2 Mbits /s (3G/HDSPA)
 ~3-6Mbits/s (4G/LTE)*

*http://nextelonline.nextel.com/
4
WI-FI ALTERNATIVE
20100408
Wi-Fi has dense coverage areas in urban areas
 Wi-Fi coverage area is small
 Wi-Fi doesn’t provide seamless connectivity
 Being always connect may not be necessary
 Wi-Fi rates are fast

PAM 2010 Zurich
11 - 54 Mbits/sec (802.11B & G)
 300 Mbits/sec (802.11N)


Potentially zero cost / MB
Open access points
 Community networks

5
3G RATES EXPOSED
3G service is expensive

$25.35/€18.80
$60(€44.50)
Internation rates

$0.0195/KB
Email
check(16K)
$760.50/€563.10
PAM 2010 Zurich
$30(€22.25)/month
Sprint


1.3MB/Day
iPhone AT&T $80 (€59.25) 39MB/Month


Cost
(USD/Euro)
20100408

International
Usage
$0.31/€0.23
Web Page
$2.93/€2.17
lookup (150KB*)
Google Map
$20.00/€14.83
Directions (~1M)
6
* http://support.sprint.com/support/article/Know_how_data_usage_is_calculated_and_charged_for_Sprint_Mobile_Broadband_plans/case-ye186054-20090916160215#__highlight&id16=what+can+I+do+with+5+gig
DO THIS NOW!
20100408
PAM 2010 Zurich
7
THE QUESTION
What is the feasibility of using Wi-Fi as a
substitute for 3G Data service
PAM 2010 Zurich

Can Wi-Fi be a substitute for data transfers that do
not have delivery deadlines


20100408

My mail app checks for mail every 15 mins
What is possible today with existing open AP
with default connection parameters
8
OUTLINE
20100408
Motivation
 3G vs. Wi-Fi Face-off Experiments
 Results
 Conclusions

PAM 2010 Zurich
9
EXPERIMENTAL SETUP
iPhone 3G

IBM T30 laptop
Ubuntu (Hardy)
 Intel 2915ABG wireless card

PAM 2010 Zurich
Jailbroken
 No hardware changes

20100408

10
EXPERIMENT LOCATION
20100408
PAM 2010 Zurich
11
EXPERIMENT ROUTE

Scan

Associate

Request IP

Ping proxy

Download/Upload

Repeat
PAM 2010 Zurich

Wi-Fi
20100408

3G

Continuous
download/upload
from proxy
12
OUTLINE
20100408
PAM 2010 Zurich
Motivation
 3G vs. Wi-Fi Face-off Experiments
 Results
 Conclusions

13
Radio
Contact Tput
Total
55MB
3G VS760Ws I-FI579.4Kbps
DOWNLOADS
WHILE DRIVING
3G
223 s
34MB
>60%
PAM 2010 Zurich
<1/3
1220Kbps
20100408
Wi-Fi
14
Radio
Contact Tput
Total
285MB
3G VS3385
WsI-F673Kbps
I DOWNLOADS
WHILE WALKING
3G
1353 s
1243Kbps 210MB
>73%
PAM 2010 Zurich
<1/3
20100408
Wi-Fi
15
Radio
Contact Tput
Total
3G VS
WI-F129Kbps
I UPLOADS
WHILE WALKING
3164 s
51MB
3G
860 s
>3.2x
PAM 2010 Zurich
<1/3
1523Kbps 164MB
20100408
Wi-Fi
16
CONCLUSION
20100408
PAM 2010 Zurich
Opportunistic Wi-Fi performs surprisingly well
when compared with 3G
 Wi-Fi could provide a substitute for 3G data
service
 3G service provider could offload traffic on Wi-Fi.
 Imaging if there was provider support!

17
PAM 2010 Zurich
Questions?
20100408
Thanks for listening
18
BACKUP
20100408
PAM 2010 Zurich
19
GSM COVERAGE
20100408
PAM 2010 Zurich
20
WIRELESS WI-FI IN THE US
20100408
PAM 2010 Zurich
21
3G UPLOADS
20100408
PAM 2010 Zurich
22
BAY AREA, SAN FRANCISCO
20100408
PAM 2010 Zurich
23
MANHATTEN, NEW YORK
20100408
PAM 2010 Zurich
24
BAD IDEA
20100408
PAM 2010 Zurich
25
WIGLE STATS
(WWW.WIGLE.NET)
Networks without crypto
7.2M (34.5%)
Networks with crypto
9.9M (47.4%)
Unique networks
20M
PAM 2010 Zurich
Total(Percentage)
20100408
Type
26