Transcript Emerging Under Water QoS Requirements and the U/W SDN

UCLA ENGINEERING
Computer Science
A SDN-Controlled Underwater
MAC and Routing Testbed
Ruolin Fan∗, Li Wei†
Pengyuan Du*, Ciarán Mc Goldrick♠
and Mario Gerla∗
* University of California Los Angeles, Los Angeles, CA, USA
† Michigan Technological University, Houghton, MI, USA
♠ Trinity College Dublin, Dublin, Ireland
UCLA ENGINEERING
Outline
•
•
•
•
•
•
Introduction
Background
Design
Testbed Implementation
Testbed Usage
Conclusion
Computer Science
UCLA ENGINEERING
Introduction
• Scientific and military operations
• Ocean floor mapping
• Ancient shipwrecks exploration
Computer Science
UCLA ENGINEERING
Introduction
• Search and rescue missions (downed
airplanes)
Computer Science
UCLA ENGINEERING
Supervised Search
• Man guides search from
vessel in real time
• Tether support fiber optic
communications
• Supplies power to USV
(Underwater Support
Vehicle) and in turns UUVs
• Covert operations
possible by using optics
only for the swarm search
Computer Science
UCLA ENGINEERING
Autonomous search
• Non real time search
• No man in the loop
• Wave actioned generator
• Guarantees resupply
• Unlimited searches
• Several km fronts can be
explored with multiple
USVs
• Video inputs processed
on USVs
• Results reported to base
via satellite
Computer Science
UCLA ENGINEERING
Outline
•
•
•
•
•
•
Introduction
Background
Design
Testbed Implementation
Testbed Usage
Conclusion
Computer Science
UCLA ENGINEERING
Computer Science
Choices for PHY Under Water
• Conventional radio waves are absorbed too quickly:
not feasible
• Acoustic PHY
•
•
•
•
Long propagation distances (kilometers)
Very high latency (speed of sound)
Small transmission rates (kbps)
Complexity: high latency require different packet collision
models
• Optic PHY
•
•
•
•
Short propagation distances (tens of meters)
Lower latency (speed of light in water)
Fast transmission rates (mbps)
Complexity: requires line of sight for transmission
UCLA ENGINEERING
Computer Science
Acoustic vs. Optical
Telemetry
Method
Range
Data Rate
Efficiency
Propagation
Speed
Acoustic
Several km
1 kbps
100 bit/Joule
1500 m/s
Optical
100 meter
1 Mbps
30,000
bit/Joule
2.55 * 108 m/s
* Farr, N.; Bowen, A.; Ware, J.; Pontbriand, C.; Tivey, M.; , "An integrated, underwater
optical /acoustic communications system," OCEANS 2010 IEEE - Sydney , vol., no., pp.1-6,
24-27 May 2010
UCLA ENGINEERING
Computer Science
Optical or acoustic?
• It depends on many things:
•
•
•
•
Water quality
Turbulence
Covertness
Mobility
• Optical needs alignment
• Energy availability
• May need to support multiple modes on the
same UUV, switching from one mode to the
next dynamically
UCLA ENGINEERING
Computer Science
Proposal: Underwater SDN
• Software defined networking (SDN):
separation of control plane with data plane
• Allows for flexibility and simplicity
• Centralized network controller defines network
behavior of other nodes
• Control plane: acoustics
• Data plane: (mostly) optics, acoustics optional
UCLA ENGINEERING
Outline
•
•
•
•
•
Introduction
Design
Testbed Implementation
Testbed Usage
Conclusion
Computer Science
UCLA ENGINEERING
General SDN Framework
Computer Science
UCLA ENGINEERING
Computer Science
Architecture and Components
• SDN components for Software-Defined Mobile
Network
• SDN controller: The central intelligence of an SDNbased Mobile Cloud
• Communicates with UUVs using long-range acoustics
• Directs UUV movements in addition to networking
• SDN wireless node: The UUVs that explore the
ocean
• Sends data to the controller mainly using optics
• Networks as directed by the controller
UCLA ENGINEERING
Computer Science
The Underwater SDN Architecture
Active UUV
Recharging UUV
Centralized Network
Controller
Docking Station
Sleeping UUVs
UCLA ENGINEERING
Computer Science
Architecture (cont)
• SDN wireless node internals
Acoustic
Local Agent contains
recovery mechanisms so
that system can still
function when
communications with SDN
controller are lost or
disrupted
Optic
Acoustic
UCLA ENGINEERING
Computer Science
The U/W SDN Control Channel
Requirements:
• Both positioning and commands
• Covert, encrypted, secure..
• One to many – efficient broadcast
• Virtual Nets ( different missions)
• Network function virtualization
UCLA ENGINEERING
Computer Science
Control Channel Standard - JANUS
• The primary advantages:
• Simplicity of design
• Among the least complicated forms of acoustic
communications yet devised.
• Robust to noise
• This signal should be detected when the signal to noise
ratio (SNR) in a given band is at better than -2 dB.
• Robust without tracking for “reasonable” amounts
of relative speed (range rate).
UCLA ENGINEERING
Computer Science
Control Channel Standard - JANUS
• Optimal approach for asynchronous, multi-access
(multi-user) applications
• Optimal for robustness in the presence of all
types of interference, including intentional
jamming.
• Potentially difficult for third parties
• Undetectable by energy detectors
• A “constant envelope” waveform
• Transmitters not concerned with amplitude crest
factors
• Allows for maximum power allocation to the
transmission.
UCLA ENGINEERING
Outline
•
•
•
•
•
Introduction
Design
Testbed Implementation
Testbed Usage
Conclusion
Computer Science
UCLA ENGINEERING
Computer Science
Testbed Implementation
• Parts of the acoustic version of the system
implemented in our WaterCom testbed
• Small water tank
• Lined with foam to attenuate acoustic waves
• Compartmentalized with foam to limit
connectivity
• 6 OFDM acoustic modems
• 3 large models with long-range signals
• 3 educational models with short-range signals
UCLA ENGINEERING
Computer Science
Testbed Implementation
• All modems connected to the WaterCom
server
• Doubles as the SDN controller
• Accessible remotely via <apus.cs.ucla.edu>
• Uses the underwater protocol stack SeaLinx
• Allows for flexible loading of protocols at different
layers
UCLA ENGINEERING
WaterCom Implementation
Computer Science
UCLA ENGINEERING
Testbed Network Topology
Computer Science
UCLA ENGINEERING
Outline
•
•
•
•
•
Introduction
Design
Testbed Implementation
Testbed Usage
Conclusion
Computer Science
UCLA ENGINEERING
Computer Science
Comparing UW MAC Protocols
• Using our testbed, we compared 2 existing
UW MAC Protocols
• Slotted FAMA (S-FAMA)
• UW-Aloha
• Under-water multi-hop scenario using
acoustic radios
• 5-minute test cases
• Varying packet size
• Varying packet sending rates
UCLA ENGINEERING
Computer Science
Experiment Network Topology
UCLA ENGINEERING
Results: Throughput
Computer Science
UCLA ENGINEERING
Results: Packet Delivery Ratio
Computer Science
UCLA ENGINEERING
Outline
•
•
•
•
•
Introduction
Design
Testbed Implementation
Testbed Usage
Conclusion
Computer Science
UCLA ENGINEERING
Computer Science
Conclusion
• Design of an under-water SDN architecture
• Acoustic control plane
• (Mostly) optical data plane
• Implementation in the WaterCom testbed
• Comparison of S-FAMA and UW Aloha
• UW Aloha has higher throughput and packet
delivery ratio