ITU-T Kaleidoscope 2009
Innovations for Digital Inclusion
Reliability and Scalability Analysis
of Low Cost Long Distance
IP-Based Wireless Networks
D. Trinchero, R. Stefanelli, A. Galardini
iXem Labs – Electronic Department
Politecnico di Torino
info@iXem.polito.it
Labs
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
Labs
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iXem research activities
wireless networks design and analysis
wireless sensor networks design
microwave sensors design
electromagnetic propagation analysis
antenna design
microwave components design
electromagnetic theory
electromagnetic compatibility
electromagnetic interference reduction
solutions for digital inclusion
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 2
Long distance (low cost) wireless links => MKM
Some authors are presenting this technology
as an affordable and practicable solution
for the construction of telecommunication infrastructures
in remote and/or harsh locations
Some other authors are strongly against it
Are we allowed to think something in the middle?
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 3
1. ASSEMBLE a real-case experiment
2. DEFINE guidelines and constrains for network design
3. IDENTIFY the most suitable (but
hardware and system architecture
also
reaistic)
4. CONSTRUCT transmitters prototypes
5. TEST solutions to enhance transmission capabilities
6. STUDY physical and mac layer limits
7. EVALUATE long term hardware living capacity
8. TEST hardware strength after exposure to hard
environmental and meteorological conditions
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 4
Ip 1: the link is bi-directional
Ip 2: the link makes use of
unlicensed frequencies
Ip 3: regulatory EIRP limitation
Ip 4: hardware very cheap
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 5
1. Large bandwidth
use microwaves
2. EIRP limitation
choose radios with high
sensitivity
3. Unlicensed freq
enhance
directivity
4. Bidirectional link
multiplex
uplink
downlink on the
antenna
5. Bandwidth
improvement
multiplex radios on the
same antenna
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
antenna
and
same
© iXem Labs 2009 - p. 6
45
40
35
30
25
20
6 Mb/s
9 Mb/s
12 Mb/s
18 Mb/s
24 Mb/s
36 Mb/s
48 Mb/s
54 Mb/s
-65
Received Power [dBm]
Antenna gain [dBi]
50
15
10
-70
-75
-80
-85
-90
-95
6
5
0
9
12
18
24
36
48
54
Max Data Rate [Mb/s]
0
50
100
150
200
250
300
350
400
450
500
Distance [km]
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 7
First objective: VERY LOW COST hardware
Solution: Use of commercial OFDM-based wireless
chipsets combined with a robust MAC layer
How: using open source wireless physical drivers and
low-cost PCs or SBCs to control the radio
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 8
Platform: Commercial PCs LINUX based
Chipset: commercial Atheros chipsets originally born for
802.11x applications
Drivers: either commercial or taken from the open
source MadWiFi projects
Frequency Band: Hiperlan (European 5 GHz unlicensed)
Antennas: standard high gain antennas (up to 35 dBi)
Communication protocol:
either
commercial
or
derived from 802.11 distributions, with some
modifications to support p2p communications
Frequency use: hybrid TDD/FDD scheme
RF components: properly designed
Output:
an experimental network to test the
identified solution
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 9
mainboard
chipset board
power supply
board
RF channel
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 10
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 11
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 12
Rondissone
Crescentino
Fontanetto
Verrua Savoia
Brusasco
Lauriano
Cavagnolo
Cerrina
Sgarbinato
Mombello
Murisengo
Politecnico di Torino
0 km
10 km
20 km
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 13
67
133 km
133 –km
67 31 Aug
km Argentina,
Mar del0 Plata,
1 Sep 2009
km
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 14
0 km
80 km
160 km
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 15
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 16
802.11
single FDD
TDD radio
antenna
downlink radio
uplink radio
antenna
downlink radio 1
multiple FDD
downlink radio 2
uplink radio 1
antenna
uplink radio 2
TDD radio 1
multiple radio
TDD radio 2
TDD radio 3
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
TDD
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
radio 4
antenna
© iXem Labs 2009 - p. 17
1. SCALABLE configuration
2. ADAPTIVE design
(*)
A
B
(*)
C
TASCONE R; SAVI P; TRINCHERO D.; ORTA R, Scattering matrix approach for the design of microwave filters,
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, pp. 423-430, 2000, Vol. 48, ISSN:
0018-9480
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 18
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 19
Single radio
Two radios
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
Four radios
© iXem Labs 2009 - p. 20
1. lightning: one transmitter destruction at Capanna
Margherita (in the same occasion also the satellite
connection was affected in the same way);
2. ice falls: solar panels damaged at Capanna Margherita
(in the same occasion also the satellite power supply
was affected in the same way);
3. overvoltage damages: two times (MB and ATX power
supply wrecked, no problems for radios), due to failures
of the solar panels regulator;
4. link down-time: around 0% for links under 100 km,
up to 4% increasing the distance to 300 km; the link
towards Capanna Margherita, in presence of strong
snowstorms,
was
experimenting
extraordinary
attenuation;
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 21
5. hardware wear: no appreciable problems for radio
cards, new ATX motherboards, automotive ATX power
supply; only one SBC failure over twenty boards, after 9
months of usage; one failure over ten recycled
motherboards, after 6 months of usage; two failures
over ten recycled standard ATX power supply;
6. strong winds: no problems, even if some hops
(Capanna Margherita) were exposed to winds up to 200
km/h;
7. extreme temperatures: destruction of two batteries
below -30° Celsius (after we started isolating them)
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 22
1. MKM networks can be reliable as a first step in the
implementation of communication infrastructures in
developing regions.
2. MKM networks can be easily installed,
installed they do not need
high expertise,
expertise can be efficient for basic service
provisioning,
provisioning they can be simply scaled up.
up
3. We must keep in mind that transmission capacity and
long term duration are not comparable with more
developed, transmission systems.
4. Thanks to their low costs, MKM networks can be
implemented for the construction of simple backhaul
networks, for essential services like telemedicine and
distance learning applications, or to start the digital
inclusion process.
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 23
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 24
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 25
Labs
iXem Mission
Where you can’t imagine to place an antenna, we (try to) DO
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 26
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 27
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 28
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 29
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 30
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 31
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 32
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 33
Long distance (low cost) wireless links
Some authors are presenting this technology
as an affordable and practicable solution
for the construction of telecommunication infrastructures
in remote and/or harsh locations
MKM link:
MKM network:
a point to point bidirectional radio
connection ranging from 50 km to
300 km, normally working on
unlicensed frequency bands
a wireless network based on a whole
of master stations interconnected by
means of MKM links
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 34
~ - 2 dBm
Tx
~ - 25 dBm
Rx
~ - 80 dBm
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 35
Mar del Plata, Argentina, 31 Aug – 1 Sep 2009
ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion
© iXem Labs 2009 - p. 36