Mo Dong
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Introduction
Definition
Cognitive radio network architecture
Dynamic Spectrum Access in CRN
1
Pros:
• Effectively controls interferenc
• Simple to design hardware
Cons:
• Multiple allocation over all of
the band
• A crisis of spectrum availability
• Utilization of 0.5% in the 3-4 GHz
• And 0.3% in 4-5 GHz
A new approach to spectrum licensing is needed
2
• “cognitive Radio” was first introduced by J.Mitola :
An intelligent wireless communication system that is
aware of its surrounding environment (i.e., outside
world), and uses the methodology of understandingby-building to learn from the environment and adapt
its internal states to statistical variations in the
incoming RF stimuli by making corresponding
changes in certain operating parameters (e.g.,
transmit-power, carrierfrequency, and modulation
strategy) in real-time, with two primary objectives in
mind:
· highly reliable communications whenever and
wherever needed;
· efficient utilization of the radio spectrum.
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FCC definition :
A ‘‘Cognitive Radio’’ is a radio that
can change its transmitter
parameters
(So must be Reconfigurable)
based on
interaction with the environment in
which it operates.
(So must have some capabilities such as
sensing)
3
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Primary network
◦ Primary users:
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Primary users have the license to operate in certain spectrum bands
◦ Primary base station:
 Controls the access of primary users to spectrum
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Secondary network
◦ Secondary users:
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Secondary users have no licensed bands assigned to them.
◦ Secondary base-station:
 A fixed infrastructure component with cognitive radio capabilities and
provides single hop connection to secondary users.
◦ Spectrum broker :
 Scheduling server shares the spectrum resources between different
cognitive radio networks.
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CR Network Access:
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CR Ad Hoc Access:
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Primary Network Access : CRs can access primary
CRs can access their own base
station on both licensed and unlicensed spectrum bands
CRs can communicate with other
CRs through an ad hoc connection on both licensed and
unlicensed spectrum bands.
base station through the licensed bands.
4
Mobility
Capacity
Connectivity
HOW TO
REALIZE
CR
Dynamic Spectrum
Access
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Opportunistic Access Model
SU is like a smart mice. They sniff
around and if there is no PU, they will
seize the day
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Collaborative Access Model
SU and PU agree on the use of
spectrum and they can temporarily
forget that they are naturally mutual
exclusive and achieve a win-win
state.
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Opportunistic Access Model
sensing
evict
access
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Collaborative Access Model
Contact with
DCN
Use it until
time expire or
PU change its
mind
Choose the
channel
wanted
Reach
Agreement on
a common
behalf
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Collaborative
Pros：
Efficiency，
Easy for infrastructure
Hard in theory
Cons:
Need across layer
design to be realized
Opportunistic
Pros：
Quick，
adaptive，
Hard in theory
Cons:
Cannot make money
Hard to implement
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Collaborative
Opportunistic
Pros：
Efficiency，
Easy for infrastructure
Hard in theory
Cons:
Need across layer
design to be realized
Pros：
Quick，
adaptive，
Hard in theory
Cons:
Cannot make money
Hard to implement
Channel
Mobility
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Game Model
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Auction Model
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Contract Model
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19
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The behavior of the cognitive radios in
dynamic spectrum access networks can be
modeled as a dynamic spectrum sharing
game (DSSG).
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Non-cooperative DSSG without centralized
control
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The focus is on distributed design and cooperation
simulation.
Cooperative DSSG
◦ users do enforceable spectrum sharing through
centralized authorities. Nash bargaining Solution plays
an important role in cooperative games.
Negotiated or leasing-based dynamic spectrum
sharing
◦ This scenario can be modeled as multiplayer noncooperative game with incomplete information. Auction
theory is applied to formulate and analyze the
interactions.
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Auction-Based Spectrum Sharing Game
◦ VCG is usually used to achieve socially optimal solution
◦ It may not be suitable for spectrum sharing because of
the temperature-constraint, information overhead and
computational burden.
Two other auctions are generally used:
◦ SINR Auction: charging secondary users according to
their received signal-to-interference-plus-noise ratio.
◦ Power Auction: charging secondary users based on their
received power
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Opportunistic Spectrum Access to 3G
Wireless CDMA Networks for Cognitive Radio
Double Auction for Spectrum Resource Allocation
using Coalitional Game Approach
Recently
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on New Frontiers in Dynamic Spectrum, 2010, pp. 1–11.
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vol. 45, no. 5, pp. 88–94, 2007.
[7] L. Chen, S. Iellamo, M. Coupechoux, P. Godlewski, P. da Vinci, and I. Milan, “An
Auction Framework for Spectrum Allocation with Interference Constraint in
Cognitive Radio Networks.”