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Transcript of 1 Cooperative MIMO Paradigms for Cognitive Radio Networks Wei Chen & Liang Hong College of...
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Cooperative MIMO Paradigms for Cognitive Radio
Networks
Wei Chen & Liang Hong
College of EngineeringTennessee State University
Dr. Liang [email protected]
(615) 963-5364
College of EngineeringTennessee State University
APDCM 2013 Boston, MA, May 20, 2013
2
Outline
• Introduction• Problem Statement• Cooperative MIMO Network Model and
Communication Schemes • Cooperative MIMO Paradigm for Overlay Systems• Cooperative MIMO Paradigm for Underlay Systems• Numerical Analysis and Experiments• Conclusions
Cooperative MIMO Paradigms for Cognitive Radio Networks
Dr. Liang [email protected]
(615) 963-5364College of EngineeringTennessee State University
3
Introduction
Dr. Liang [email protected]
(615) 963-5364
Cooperative MIMO Paradigms for Cognitive Radio Networks
College of EngineeringTennessee State University
T×1
T×2
T×M R×M
R×1
R×2
T×1
T×2
T×M R×M
R×1
R×2
Wireless MIMO network
MIMO Technology−Multiple antennas transmit same data streams simultaneously: it can be used to reduce energy, or extending communication range and error rate. −Multiple antennas transmit different data streams simultaneously: it can be used to provide higher data rate (multiplexing gain)
multiplexing gaindiversity gain
MIMO transceiver
However, it is unrealistic to equip multiple antennas to small and inexpensive wireless devices (e.g., wireless sensor nodes).
Dr. Liang [email protected]
(615) 963-5364
Cooperative MIMO Paradigms for Cognitive Radio Networks
College of EngineeringTennessee State University
Cooperative Communication MIMO Technology
– Distributed individual single-antenna nodes cooperating on information transmission and reception as a multiple antenna array
First hop Other hops
MIMO LinkMISO LinkSIMO LinkSISO Link
MIMO links
Cooperative MIMO Schemes
5
Cognitive radio A promising paradigm in wireless communication that enables efficient use of frequency resources
− Coexistence of licensed primary users (PUs) and unlicensed secondary users (SUs) in the same frequency band
− Cognitive capabilities
Basic approaches: (1) spectrum overlay, (2) underlay, and (3) interweave
Dr. Liang [email protected]
(615) 963-5364
Cooperative MIMO Paradigms for Cognitive Radio Networks
College of EngineeringTennessee State University
A cooperative SIMO link
A cooperative MISO link
Secondary Users
PT PR
an mt×mr cooperative MIMO link
SRST
Primary Users
Overlay Underlay Interweave
time
6
• Existing overlay schemes require the relay SUs to be in the convenient location, typically halfway between source and destination
• Existing underlay schemes cannot guarantee that the aggregated interference generated by SUs is maintained below the threshold
Dr. Liang [email protected]
(615) 963-5364
Cooperative MIMO Paradigms for Cognitive Radio Networks
College of EngineeringTennessee State University
Problem Statement
This Research
Develop energy efficient cooperative MIMO paradigms that can maximize the diversity gain and significantly improve the performance of both overlay and underlay systems.
7
Network Model and Communication Schemes
Dr. Liang [email protected]
(615) 963-5364
Cooperative MIMO Paradigms for Cognitive Radio Networks
College of EngineeringTennessee State University
Underlying network: Network G = (V,E) of single-antenna radio nodes.
d-Clustering: the distance between two nodes in a cluster ≤ d. d-clusters are called Cooperative MIMO nodes, and the nodes of G are called primary nodes.
D-Cooperative-MIMO links: Let A and B be two d-clusters, and A’ and B’ be the subsets of A and B, respectively. Suppose there are mt nodes in A’ and mr nodes in B’. If the largest distance between any node of A’ and any node of B’ is not larger than D, a D-mt×mr virtual MIMO transmission link can be defined between A and B.
Heterogeneity: The size and the diameter of a cluster, and the length of virtual MIMO links can be different.
3×2 MIMO link
8
Cooperative MIMO Paradigm for Overlay System
Dr. Liang [email protected]
(615) 963-5364
A cooperative SIMO link A cooperative MISO link
− Step 1: data transmission from the
primary transmitter to m SUs via 1×m
SIMO link
− Step2: data transmission from m SUs
to the primary receiver via a m×1
MISO link
Cooperative MIMO Paradigms for Cognitive Radio Networks
College of EngineeringTennessee State University
Optimization (at SUs)•Maximize the distance that the secondary users can be away from the primary users.•Minimize the energy usage at the secondary users.
SUs assistant PUs’ communication: (SUs can use the PUs channel when PUs’ communication completed)
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Cooperative MIMO Paradigm for Underlay System
Dr. Liang [email protected]
(615) 963-5364
Secondary Users
PT PR
mt×mr cooperative MIMO link
SRST
Primary Users
Cooperative MIMO Paradigms for Cognitive Radio Networks
College of EngineeringTennessee State University
SUs utilize PUs’ channel obliviously: SUs share the PUs’ frequency resource without any knowledge about the PUs’ signals and under the strict constraint that the spectral density of their transmitted signals fall below the noise floor at the primary receivers
Optimization at SUs•Maximize the communication performance (minimize error rate)•Minimize the energy usage at the secondary users.
10
Dr. Liang [email protected]
(615) 963-5364
Energy Model
− Energy consumption per bit at each primary node for local/intra data
transmission
− Energy consumption per bit at each primary node for local/intra
reception
LtC
LtPA
Lt eee
22 )21(4
ln3
)12)(1(4 fd
b
bb
LtPA NG
bPbe
nTPbBPe trsynctLtC /)/(
nTPbBPe trsyncrLr /)/(
Cooperative MIMO Paradigms for Cognitive Radio Networks
College of EngineeringTennessee State University
Numerical Analysis and Experiments
11
Dr. Liang [email protected]
(615) 963-5364
− Energy consumption per bit at each primary node for data transmission in long-haul mt
× mr cooperative MIMO link
− Energy consumption per bit at each primary node for data reception in long-haul mt ×
mr cooperative MIMO link
MIMOtC
MIMOtPA
MIMOt eemrmte ),(
flrt
bbMIMOtPA NM
GG
D
b
mrmtbPee
2
2)4(
3
),,,()1(
bBPPe synctMIMOtC /)(
)/()( bBPPe syncrMIMOr
Cooperative MIMO Paradigms for Cognitive Radio Networks
College of EngineeringTennessee State University
12
Dr. Liang [email protected]
(615) 963-5364
− Parameters
Pct = 48.64 mw Pcr = 62.5 mw
Psyn = 50 mw Nf = 10 dB
Ttr = 5 μs σ2 = N0/2 = -174 dBm/Hz
GtGr = 5 dBi λ = 0.1199
Gd = G1dkMl (G1 = 10 mw, k = 3.5, Ml = 40 dB)
)12(35.0
)12(3
b
b
2for ,1
3
2
11
42/
b
M
bQ
bp b
bHb
1for ,2 bQp bHb bM 2
mtN
mrmybpeH bbFb
0
2),,,(
tscoefficien channel :H
Cooperative MIMO Paradigms for Cognitive Radio Networks
College of EngineeringTennessee State University
13
Numerical analysis in Overlay System
Dr. Liang [email protected]
(615) 963-5364
− Step 1: data transmission from the
primary transmitter to m SUs via 1×m
SIMO link
− Step2: data transmission from m SUs
to the primary receiver via a m×1
MISO link
),1( mee MIMOtPt MIMOr
sr ee
)1,(mee MIMOtSt MIMOree Pr
Cooperative MIMO Paradigms for Cognitive Radio Networks
College of EngineeringTennessee State University
given are and whendistanceslargest thefind .2
energy minimizingby of valueoptimal thefind .1
nodesprimary the tonodes SU thefrom distanceslargest theDetermine
SPA
SrStS
EE
EEEb
Secondary Users
PT PR
mt×mr cooperative MIMO link
SRST
Primary Users
14
Numerical Analysis in Underlay System
Dr. Liang [email protected]
(615) 963-5364
Since only transmission energy brings
interference from SUs to primary receiver,
only the transmission energy is considered
−Intra/local transmission
−Long-haul transmission
LtPA
Lt ee
MIMOtPASt emte
),max( MIMOtPA
LtPAPA emteE
Cooperative MIMO Paradigms for Cognitive Radio Networks
College of EngineeringTennessee State University
PAEb minimizingby of valueoptimal theFinding
Secondary Users
PT PR
mt×mr cooperative MIMO link
SRST
Primary Users
15
Numerical Analysis Results
Dr. Liang [email protected]
(615) 963-5364
In overlay systems the SUs can assist/relay the PUs’ transmission even when SUs are far away from primary transmitter (Pt) and primary receiver (Pr)
Cooperative MIMO Paradigms for Cognitive Radio Networks
College of EngineeringTennessee State University
16
Dr. Liang [email protected]
(615) 963-5364
In underlay systems the SUs are able to share the PUs’ frequency resource without any knowledge about the PUs’ signals and under the strict constraint that the spectral density of their transmitted signals fall below the noise floor at the primary receivers.
Cooperative MIMO Paradigms for Cognitive Radio Networks
College of EngineeringTennessee State University
Dr. Liang [email protected]
(615) 963-5364
System Evaluation in Real Wireless Environment Build a cooperative cognitive testbed using the universal software radio peripheral (USRP) platform and GNU Radio
−Each node consists: an USRP motherboard + RFX2400 daughterboard −signal processing module implemented in GNU Radio running in a general purpose computer under Ubuntu operating system −BPSK modulation and demodulation is used for all experiments
Underlay System Overlay System
Licensed Primary Transmitter
Licensed Primary Receiver
unlicensed Secondary Transmitter
unlicensed Secondary Cooperative Transmitter
unlicensed Secondary Receiver
unlicensed Secondary Users as Relay
Cooperative MIMO Paradigms for Cognitive Radio Networks
College of EngineeringTennessee State University
17
Dr. Liang [email protected]
(615) 963-5364
Multiple Relays Coop.(Node Distance: 30 ft)
Single Relay Cooperation
Without Cooperation
2.93% 2.21% 9.13%
Cooperative MIMO Paradigms for Cognitive Radio Networks
Overlay System Underlay System
(Bit error rate performance) (Packet error rate performance)
•Single-relay Cooperation
•Multiple-relay cooperation
Trial(Node distance: 2 m)
With Cooperation
Without Cooperation
1 2.21% 9.13%
2 2.27% 12.73%
3 2.89% 10.76%
Average 2.46% 10.87%
Amplitude With Cooperation
Without Cooperation
800 0 24.85%
600 6.12% 70.28%
400 13.72% 97.1%
Average 6.61% 64.08%
College of EngineeringTennessee State University
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19
Conclusions
• Proposes energy efficient cooperative MIMO paradigms for cognitive radio networks.
• In overlay systems, SUs can relay the primary transmissions even when they are far away from the primary users
• In underlay systems, SUs are able to share the primary users’ frequency resources without any knowledge about the PUs’ signals, even when they are close to the primary receivers
• Performance evaluation in real wireless environment verified the advantage of the proposed paradigms.
Dr. Liang [email protected]
(615) 963-5364
Cooperative MIMO Paradigms for Cognitive Radio Networks
College of EngineeringTennessee State University
20
Dr. Liang [email protected]
(615) 963-5364
Thank you!
Questions?
College of EngineeringTennessee State University
Cooperative MIMO Paradigms for Cognitive Radio Networks