Comparing Underwater MAC Protocols in Real World
Lina Pu, Yu Luo, Haining Mo, Son Le, Yibo Zhu, Zheng Peng, Jun-Hong Cui
Computer Science & Engineering, University of Connecticut
1
1 DATA
UW-Aloha:
Experiment Settings
ACK
ACK timer
Use ACK to acknowledge successful reception.
0
ACK timer
retransmission reached.
send
0
2
Retransmit if packet lost unless maximum number of
Transmission Rate:
saturate
4
recv
Each node sense the channel before transmission.
Teledyne Benthos ATM-88X modem
3
1
Random Access.
Acoustic Modem:
2
1 DATA
ACK
0
2
300 bps or 600 bps depends on channel quality
1
SASHA
Target Location:
2
3
4
RTS
CTS
Selective Arq and Slotted Handshaking based
A strip area about 120 km off New Jersey shore
Use RTS/CTS to reserve channel.
1
2
Data packets can be sent in a burst.
Topology: 9 nodes in a 8-hop string
recv
1 DATA
2
Sender send HDR to notify receiver the
Deployment:
NACK
HDR
retransmission and continue to reserve channel.
Depth 80m, Average Distance 1 km
send
1
2
2
Use ACK to acknowledge successful reception.
2
ACK
Software:
Pipelined MAC:
Embedded Linux Aqua-Net, a layered structure
1
All nodes are scheduled.
Packet Size: 200B and 500B
Slot 1
Node transmit packet in pipeline.
Traffic Rate: 8 to 60 bit per second
Slot 2
No adjacent three nodes are allowed to send
Destination node responses explicit ACK at
N
3
Slot 4
4
1 DATA
Remarks
1
recv
1
Implicit ACK
send
1
1
Slot 3
simultaneously.
(39° 6.565'N, 73° 0.000'W)
2
Fig. 1 End-to-End Goodput Performance
1
2
ACK
2
successful reception.
• The energy efficiency of Pipelined MAC is
(39° 6.036'N, 73° 0.000'W)
overall the best. However the difference is not
4.5
significant at low traffic rate.
4
Packet Delivery
(39° 5.507'N, 73° 0.000'W)
(39° 4.453'N, 73° 0.000'W)
goodput than SASHA and UW-Aloha especially
at high traffic rate.
Fig. 2 Average Number of Packets Received in each Node along the Path
(39° 4.980’N, 73° 0.000'W)
• Pipelined MAC achieves higher end-to-end
3.5
• The superiority of Pipelined MAC benefits from
3
2.5
Pipelined
2
1.5
the scheduling scheme. The goodput saturation
UW-Aloha
of Pipelined MAC depends on the modem
SASHA
transmission rate and the packet lost proba-
1
bility.
0.5
0
1
2
3
4
(39° 3.912'N, 73° 0.000'W)
5
6
7
Hops
Fig.3 Normalized Energy Consumption for each Successful Data Transmission
(39° 2.842'N, 73° 0.000'W)
(39° 2.687'N, 73° 0.566'W)
Real Sea Experiment in Atlantic Ocean
Cooperate with Naval Research Laboratory (NRL)
September, 2012
RESEARCH POSTER PRESENTATION DESIGN © 2012
www.PosterPresentations.com
8bps data
generation rate
poor
collision
avoidance
handling
and
unfairness in multi-hop networks.
9
Normalized Energy
Consumption
(39° 2.589'N, 73° 0.285'W)
• UW-Aloha has the lowest goodput due to its
8
• Due to the increasing collision probability at
8
7
high network load, SASHA only achieve slightly
6
5
Pipelined
4
UW-Aloha
3
SASHA
2
increase on goodput.
• SASHA also has poor fairness in multi-hop
networks, which becomes another reason for its
1
0
1
2
3
4
5
6
7
8
low goodput.
Hops
Lina Pu
lina.pu@engr.uconn.edu