Download Chan

Communication and Network Group
Principal Investigator:
Post Doctoral Fellow:
Students:
Vincent Chan
Joseph Junio
Lei Zhang, Matthew Carey, Henna Huang,
Manishika Agaskar, Jessica Weaver, Esther Jang
WHO WE ARE
Circuits,
Systems,
Signal and
Communication
RESEARCH PROJECTS OVERVIEW
Set in a heterogeneous network backdrop, our research projects cover a wide range of research fields in
communication and networks, spanning from fiber, to wireless, to free space optical systems, into a connected
heterogeneous network.
Fiber Networks
Vincent Chan
o Design and analyze future optical flow-switched networks
 Architecture design and network management and
control (Lei Zhang)
 Physical layer impairments study (Joseph Junio)
 Transport layer protocol design and analysis (Henna
Huang)
Joseph Junio
Wireless Networks
Lei Zhang
Matthew Carey
o Directional antenna arrays and electronic beamforming in
infrastructureless wireless networks (Matthew Carey)
Henna Huang
Free Space Optical Systems
Manishika Agaskar Jessica Weaver
o Design and analysis of a free space optical system with
controllable direction of energy propagation (Manishika
Agaskar)
o Optical wireless networking (Jessica Weaver)
Esther Jang
Fiber Networks
Motivation
Wireless Networks
User terminal
o Bandwidth abundance of fiber network is
bottlenecked at routers/switches
o Ever-increasing of data traffic calls for a hybrid
future network of (Fig. 2)
 all-optical network serving large-volume data
 Existing network serving small-size data
User terminal
Virtual connections between
Transport Layer and Control Plane
Acq via IP
Application
Control Plane
Transport
Layer
Scheduling
Motivation Rapidly deployable mobile ad hoc networks are
Transport
Layer
needed
o Emergency disaster relief
o Military theater communications
Background Limitations of past systems
o Highly susceptible to disconnection
o Limited scalability
Approach Use directional antenna arrays and electronic
beamforming to:
o Increase communication range without driving up power
o Reduce interference and enable spatial frequency reuse
Optical Flow Switching Service
Background
Directional Infrastructureless Wireless Networks
Application
IP Service
Network Layer
Optical Flow Switching is key enabler of costeffective and energy-efficient future optical
networks (Fig. 3)
o Data is sent along scheduled end-to-end path
in optical signals in the data plane, bypassing
routers and E-O-E conversions
o A control plane is used to manage the whole
network, perform scheduling, network
reconfiguration, and faults diagnostic, etc
Figure 1: Illustration of a heterogeneous network
Figure 2: Systematic illustration of a network with
hybrid IP and optical flow switching services
Figure 8: A directional
infrastructureless wireless
network
Results Our work reveals:
o Order of magnitude device density reduction for desired network connectivity
o Characteristic-distance hopping schemes that achieve optimal throughput, delay, and energy
scaling
Challenges
# of users coupled
104
106
108
Ultra-Fast scheduling in 1 RTT <100mS
Most challenging
LAN/MAN MAC
102
101
Fast:per-session
From the system level, work across multiple
network layers to:
o Characterize and experimentally verify power
transients & excursions in fiber
o Design transport layer protocol to address
physical layer impairments and large delay
bandwidth product of fiber channel, using file
segmentation and reassembly, interleaving with
forward error-correction, and frame
retransmission
o Design and analyze network management and
control plane together with network
architectures
o Reduce control plane complexity by designing
tunneled WAN, slowly-reconfigured MAN, and
fast-switching LAN
Population/time-scale ~ constant
1
10
102
103
S
short term average
quasi-static
5
Node C
Node B
4
6
3
7
Figure 5: Diagram showing 3
possible routes for channels to
traverse to terminate at OA 7
2
8
1
9
Route A
Node A

PO1  RGM P1  GM
7
j 1

6
P (dB)
5
4
3
Henna Huang
5
10
15
20
25
30
35
40
Added Channels
Expected Throughput Efficiency
Joseph Junio
0.992
0.991
0.99
0.989
=0
=1
=2
=3
=4
=5

0.988
0.987
0.986
0.985
10
4
45
Figure 6: Power excursion
(dB) measured at OA 7
output for channel 1540.1
nm as 40 channels are
added along different
Routes
Figure 7: Fig 1. Expected
throughput efficiency vs.
frame length and Γ, the
number of correctable
burst errors per frame
0.993
Data Link Layer
Physical Layer
0

 R  f g j t j  Pj  GM R  f g I N I  f GM g R N R  RGM NC
Route A
Route B
Route C
6
10
Frame Length
10
8
Figure 10: Example
infrastructureless wireless
network routing schemes
Free Space Optical Systems
Motivation
Route C
Route B
1
Lei Zhang
Direct transmission routing
Cell routing (based on characteristic
distance hopping)
Whisper to nearest neighbor
routing
Figure 4: Time scale of action and number of users
within each control region of the network management
and control architecture for LAN, MAN and WAN
2
Network Layer
WAN NM&C
switching
MAN NM&C
switching
Ultrafast
Approach
Transport Layer
Figure 9: Moving from
omnidirectional antennas to
directional antenna arrays
Figure 3: Illustration of a flow-switched optical network
Subsystem scale
o Large scale network with stochastic requests
o Physical layer impairment of power transients
& excursions induced by amplifiers during
wavelength switching
o Existing transport layer protocols perform
badly with large bandwidth delay product and
burst errors of fiber channels
o Complexity and scalability of control plane
correlates with network architecture design
o Free space optical systems provide cheap, easily deployable
solutions for high data rate communications
o Controlling the direction of energy propagation from optical
transmitter prevents interference and reduces susceptibility to
eavesdropping
Goal Maximize the power transmitted from an optical aperture
array to the intended receiver of a free space optical
communications link while limiting the power transmitted to a
broadly defined region within the main lobe
Results we can suppress by >10 dB the power to a defined
suppression region 0.2 beam widths away from the user without
requiring a significant increase in transmitted power
Figure 12: Radiation
pattern with intended
user and desired 10 dB
suppression region shown
Figure 11: System setup
Figure 13: Decrease in power at
intended user vs. distance of
suppression region from receiver