1. Wi-Fi Maritime Communications Using TV White Spaces MsC Dissertation
Luciano Jorge Silva Santos
Supervisor Manuel Ricardo
Co-supervisor Rui Campos

2. Wi-Fi Maritime Communications Using TV White Spaces
Contents
Introduction
Current Maritime Communications
Context
Motivation
Previous Work
Maritime Environment
Outdoor long range link TVWS
Propagation models
On going Work
Theoretical Results
Hardware
Scenario
Experiments
Wi-Fi Maritime Communications Using TV White Spaces

3. Current Maritime Communications
Most common used Technologies
HF and VHF bands
Satellite connections
Low bandwidth and expensive
2G/3G (near the shore)
Motivation
A need for low cost communications
A need for high bandwidth and speed networks
Real time data transfers
Live VoIP and video surveillance streaming
Data exchange between fishing boats
Wi-Fi Maritime Communications Using TV White Spaces

4. Wi-Fi Maritime Communications Using TV White Spaces
Motivation
Not viable to install base stations in the high sea
Connection range up to 100 Km from the shore
Transition to digital television
700 MHz band released by analogic television
Longer transmission ranges
Better propagation characteristics in comparison with 2.4 GHz and 5.8 GHz
No current tests done with this band in maritime environment
Wi-Fi Maritime Communications Using TV White Spaces

5. Wi-Fi Maritime Communications Using TV White Spaces
Maritime Environment
Completely different from land environment
Difficult to predict maritime state
Frequency propagation over water
Surface multipath reflection
Wave occlusion
Blockage RF signal by near boats
Boat rocking motion
Continuous changes in the antenna orientation and height
These factors provokes
Unstable connection
Strongly affects signal strength
Long delays
Increase PER
Wi-Fi Maritime Communications Using TV White Spaces

6. Propagation model for maritime communications
Proposed 2 Ray Path Loss model
L = Path Loss dB
ht = Transmitter antenna height
hr = Receiver antenna Height
d= Distance (m)
λ = Wavelength
Signal reflection on the sea surface (two ray)
ht=hr=18m F=2,4 GHz
Wi-Fi Maritime Communications Using TV White Spaces

7. Outdoor long distance link with TVWS band
System configuration
Equipment
Mikrotik RB433 router boards
Ubiquiti XR7 700 MHz cards
14 dBi Yagi Directional antennas
Configurations
Tx power: 28 dBm
Channel width 5 Mhz
802.11b
7 m
18 m
50 m
Variation of RSSI between node 1 and 2
Node 1 to 2
Node 1 to 3
Node 2 to 1
Node 2 to 3
Node 3 to 1
Node 3 to 2
1.62 Mbps
1.8 Mbps
1.65 Mbps
0.67 Mbps
1.63 Mbps
0.65 Mbps
Wi-Fi Maritime Communications Using TV White Spaces

8. Wi-Fi Maritime Communications Using TV White Spaces
Scenario
ANACOM Restrictions:
Max Tx Power: 28 dBm
Channel Width: 5 MHz
Frequencies between: MHz
Wi-Fi Maritime Communications Using TV White Spaces

9. Wi-Fi Maritime Communications Using TV White Spaces
Hardware
Hardware
2x Alix 3D3 Pc engine
2x Flash compact cards
2x Ubiquiti XR7
Proprietary 700MHz, based on g OFDM
TX Channel Width Support 5MHz / 10MHz / 20MHz
Outdoor range up to 50 Km
2x Omni Directional Antenna
MHz
3 dBi gain
GPS USB
Omni Directional Antenna
Ubiquiti XR7 card
Alix 3D3
Wi-Fi Maritime Communications Using TV White Spaces

10. Wi-Fi Maritime Communications Using TV White Spaces
Experiments
Analyse the performance of the 700 MHz link in maritime environment with the following parameters:
Range – Average distance possible to establish a connection between the land station and the boat
Connection throughput – Average bandwidth for different ranges between the land station and the boat.
Packet delay and Packet loss – Round Trip Time and the percentage of packets loss for different ranges
Jitters - Variation of time between arriving packets
RSSI throughput – Received Signal Strength in dB
TCP and UDP tests
Analyse the results with meteorological conditions
Wi-Fi Maritime Communications Using TV White Spaces

11. Wi-Fi Maritime Communications Using TV White Spaces
Theoretical Results
Considering following parameters:
Transmitted:
Tx Power: 30 dBm
Antenna Height: 20m
Antenna gain: 3 dBi
Attenuation: 0.94 dB
Received:
Min Power: -88 dBm
Antenna Height: 5m
Tolerance: 6 dB
Max Path loss: dB
Max Distance: 7530 m
Fresnel Zone: m
Wi-Fi Maritime Communications Using TV White Spaces