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State of the Art in Cognitive Radio
ByMohsen M. Tantawy
National Telecommunication Institute (NTI), Egypt.
2
Contents
Introduction
CR Network Architecture
MAC Protocols for CRNs
Routing in CRNs
TCP in CRNs
CRN Security
CR Standards
New Trends in CR
CR in 5G
New Applications in CR
Green CR
Cloud-based CR
CRSN
Regulatory Issues in CR
CR Business Model
IntroductionCognitive Radio Motivation
• Spectrum scarcity – Increase in spectrum demand – Spectrum is a scarce resource – Static spectrum allocation policy
Source: http://ntra.gov.eg
4
IntroductionCognitive Radio Definitions
• Mitola
• ITU
• FCC
• NTIA
• WWRF
• They talk about – “radio”.
– “interaction with the environment”.
– “measuring”.
– “decision making”.
– “automaticity”.
– “adaptation”.
More Definitions
5
Dynamic Spectrum Access
• CR technology works on the principle of DSA, where CR users utilize spectrum holes.
Source: Natarajan Meghanathan, “Cognitive Radio Technology Applications for Wireless and Mobile Ad Hoc Networks”, IGI Global Publisher, 2013. More
6
Cognitive Radio Network Architecture
Source: Geoffrey Ye Li, “Cognitive Radio Networks Project”, Georgia Institute of Technology, 2013.
7
Spectrum Allocation and Sharing Schemes
Spectrum Allocation and Sharing Schemes According to Three Criteria
Network Architecture
Centralized
Model
Distributed
Model
Spectrum Bands in use by a CR User
Open Spectrum Sharing Model
Hierarchical
spectrum modelSp
ectrum Underlay
Spectrum Overlay
Access Behavior of CR Users
Cooperative
Model
Non Cooperat
ive Model
More about Underlay, Overlay, and Interweave
8
Underlay vs. Overlay
PU - Primary Users
SU - Overlay CR
SU - Underlay CR
Frequency
PSD
PU PUPU
More about Underlay, Overlay, and Interweave
9
Cognitive Radio MAC Protocols - Example
More about Cognitive Radio MAC Source: Mahfuzulhoq Chowdhury, Asaduzzaman, and M. Fazlul Kader, “Cognitive Radio MAC Protocols: A Survey, Research Issues, and Challenges”, Smart Computing Review, vol. 5, no. 1, 2015.
•Time-slotted•Random Access•Hybrid
CR MAC
•Single Radio•Multiple RadioRadio
•Centralized•DistributedArchitecture
•Without CCC•With CCC•Global•Local
CCC
10
Detailed Classifications of Distributed MAC Protocols - Example Considering Common Control Channel (CCC)
Distributed MAC
Single Radio
Without CCC(e.g., POMDP) With CCC
Global Time
Synch.(Netw
ork Wide)(e.g.,
C-MAC)
Local Time
Synch.(only neighboring nodes
)(e.g., HC-
MAC)
Multiple Radio
Without CCC(e.g., CA MAC) With CCC
Dedicated
Global (e., OP-
MAC)
Dynamicall
y Configurable
Global (e.g., DOSS)
Local (e.g., Comesh)
Source: Mahfuzulhoq Chowdhury, Asaduzzaman, and M. Fazlul Kader, “Cognitive Radio MAC Protocols: A Survey, Research Issues, and Challenges”, Smart Computing Review, vol. 5, no. 1, 2015.
C-MAC: Cognitive MACHC MAC: Hardware Constrained MACPOMDP: partially observable Markov decision processDOSS: Dynamic Open Spectrum SharingOP-MAC: Opportunistic MACCA-MAC: Concurrent MAC
11
Routing in CRNs
Source: Natarajan Meghanathan, “A Critical Review of the Routing Protocols for Cognitive Radio Networks and a Proposal for Load Balancing Local Spectrum Knowledge Based Routing”, Computer Science & Information Technology (CS & IT), pp. 17–26, 2013.
• Relay Nodes• Spectrum for each link
Routing Deciding
• Full Spectrum Knowledge• Local Spectrum Knowledge
Routing According to
• Minimum Delay• Maximum Throughput• Minimum Power• Link Stability
Local Spectrum Knowledge Metrics
12
Transport Layer Issues in CRNs
TCP in CR
PU Behavi
or
Spectrum
Sensing
Spectrum
Changing
BW variation
due to Spectrum
Availability
More about TCP in Cognitive Radio
In addition to traditional network congestion, Link error, collision, mobility, …etc.
Source: X. Zhong, Y. Qin, and Li Li, “Transport Protocols in Cognitive Radio Networks: A Survey”, KSII Transactions on Internet and Information Systems (TIIS), vol. 8, no. 11, pp. 3711-3730, 2014.
13
CR Attacks and Countermeasures
Attack Countermeasures
Attacks on CCC CCC Frequency hopping, CCC key distribution
PUE Attacks(malicious or selfish SU)
priori known characteristics of PU signals, location determination techniques, access to geo-location information about a priori known PUs
Spectrum Sensing Data Falsification (SSDF) Attack
(Byzantine attack)
Mutual authentication, data integrity, and data encryption, Deployment of dedicated trusty sensors, mechanisms to selectively forget past information.
Jamming Attack(trigger DoS)
Channel surfing, or frequency hopping, legitimate users change their location to escape the interference range imposed by the attacker.
Objective Function Attack(manipulate the values of the radio
parameters)
No good solution has been suggested, A simple suggestion is to define threshold values for every updatable radio parameter, help from IDS.
More Cognitive Radio Attacks
Source: Marinho et al, “A survey on security attacks and countermeasures with primary user detection in cognitive radio networks”, EURASIP Journal on Information Security, 2015.
14
Cognitive Radio Attacks by Layers
Physical Layer Attacks
Jamming
PU Emulation
Overlapping SU
Objective Function Attacker manipulates trans. rate parameters so calculated results of the function are biased towards
the attacker’s interests
More Cognitive Radio AttacksSource: Deanna Hlavacek, J. Morris Chang , “A layered approach to cognitive radio network security: A survey”, Journal of Computer Networks, 2014. http://dx.doi.org/10.1016/j.comnet.2014.10.001
15
Major Standardization Organizations and Standards for Cognitive Radio
• Institute of Electrical and Electronic Engineers (IEEE)
– IEEE 802.11af-2014: Wireless Local Area Network based on TVWS (White-Fi)
– IEEE 802.22-2011: Cognitive Wireless Regional Area Network (WRAN)
– IEEE 802.15.4m-2011: Wireless Personal Area Network (Low Rate PAN in TVWS)
– IEEE 802.19.1: Solves the coexistence problem by coordinating spectrum usage by several networks in
the same area
– IEEE 1900.4a (SCC41 or DySPAN): Optimize the resource usage when many different types of networks
are available.
• Internet engineering task Force (IETF)
– IETF Protocol to Access White Space (PAWS)- RFC 7545: Database access
• International Telecommunication Union (ITU)
– ITU-WP1B: International Telecommunication Union Working Party 1B – Spectrum Management
Methodologies
• European Telecommunications Standards Institute (ETSI)
– ETSI BRAN: European Telecommunications Standards Institute Broadband Radio Access Networks
• European Association for Standardizing Information and Communication Systems.
– CEPT ECC SE43: European Conference of Postal and Telecommunications Administrations Electronics
Communications Committee Spectrum Engineering
16
Game Theory in Cognitive Radio
Game Theory in CR has
3 Compon
ents
• Set of Players
• Set of Actions
• Utility Function
Game theory in CR has two types: • Cooperative game theory: aims to maximize
total network performance by achieving Nash Bargaining state. Individual user shares their vital information like utility with other users in network.
• Non cooperative game theory which considers CR users as rational users and aims to maximize their own utility function i.e., allocating resources. – This type of game converges at Nash
equilibrium state– Stackelberg models : One CR user serves as
leader and implement its decision before other CR users and anticipate the reacts to its decision.
Source: U. Sharma, P. Mittal and C. Nagpal, “ Implementing Game Theory in Cognitive Radio Network for Channel Allocation: An Overview”, International Journal of Energy, Information and Communications vol. 6, no. 2, pp. 17-22, 2015.
17
New Trends in Cognitive Radio
Cognitive Radio in 5G
New Applications for CRNs
Green Cognitive Radio Networks
Cloud-based Cognitive Radio
Enhancement in CR MAC Protocols
Wireless Sensor Network-aided Cognitive Radio (CRSN)
Regulatory Aspects of CRNs
Cognitive Radio – Business Model
18
New Trends in Cognitive Radio
Cognitive Radio in 5G
New Applications for CRNs
Green Cognitive Radio Networks
Cloud-based Cognitive Radio
Enhancement in CR MAC Protocols
Wireless Sensor Network-aided Cognitive Radio (CRSN)
Regulatory Aspects of CRNs
Cognitive Radio – Business Model
19
Cognitive Radio and 5G(CR role in 5G)
• Transmission Adaption: CR can dynamically and
autonomously adjust the operating parameters to satisfy
the QoS requirement by offload delay tolerant data traffic
to different tiers and radio access technologies .
Massive growth in
Connected Devices
“Communicating machines”
“50 billion devices in 2020”
More about 5G
UDND2D
MNSON CR
help 5G in
femto 2 femto
femto 2 macro
Intercell
Interference
Mitigation
20
Cognitive Radio and 5G(Challenges)
Spectrum sensing with focus on 5G
systems
Geo-location DB for 5G
CRNs
Cognitive Radio with
Massive MIMO for 5G communicatio
ns
More …
IEEE Communication Society - SIG on Cognitive Radio for 5G
MAC for 5G-CRNs
D2D comm. In 5G CRNs
5G-CRNs public safety
comm.
Cognitive small cells in 5G cellular
systems
21
New Trends in Cognitive Radio
Cognitive Radio in 5G
New Applications for CRNs
Green Cognitive Radio Networks
Cloud-based Cognitive Radio
Enhancement in CR MAC Protocols
Wireless Sensor Network-aided Cognitive Radio (CRSN)
Regulatory Aspects of CRNs
Cognitive Radio – Business Model
22
New Applications for Cognitive Radio
Cognitive Radio
Applications (sample)
Healthcare
Emergency and Public
Safety
Smart Grid
Vehicular Networks
Mobile Network
s
Unmanned Aircraft Systems
(UAS)
23
Cognitive Radio Architectures for Unmanned Aircraft Systems (UAS)
Policy DB
Geolocation and DB With PU
Geolocation and DB Polling Without PU
Source: Timothy X. Brown, Mark McHenry, and Suppapol Jaroonvanichkul, “Cognitive Radio Architectures for Unmanned Aircraft Systems”, Handbook of Unmanned Aerial Vehicles, Springer, 2013.
24
Cognitive Radio Architectures for Smart Grid
A. Aijaz, S. Hongjia, A. Aghvami ,” CORPL: A Routing Protocol for Cognitive Radio Enabled AMI Networks”, IEEE Transactions in Smart Grid, vol. 6, no. 1, pp. 477 – 485, 2015.
Advanced metering infrastructure (AMI) or field area networks (FANs) carry info between smart meters and network gateway (power sub-station, pole-mounted device, or a comm. tower.
Home/building area networks (HANs) connect smart meters with home appliances.
WAN serves as the backbone for communication between network gateways and the utility data center.
Cognitive Radio
25
New Trends in Cognitive Radio
Cognitive Radio in 5G
New Applications for CRNs
Green Cognitive Radio Networks
Cloud-based Cognitive Radio
Enhancement in CR MAC Protocols
Wireless Sensor Network-aided Cognitive Radio (CRSN)
Regulatory Aspects of CRNs
Cognitive Radio – Business Model
26
Green CRNs
• Green CRN requires – Not only the optimization of dynamic spectrum access
– But also the optimal utilization of green energy.
Source: X. Huang, T. Han, N. Ansari, “On Green Energy Powered Cognitive Radio Networks”, TR-ANL-2014-003, New Jersy Institute of Technology, 2014.
• Energy
Minimization
• Performance
Maximization
• Utility
Maximization
27
Energy Efficiency via Cognitive Radio
• Green Relaying,
• Cooperative CRNs– Between SUs.
– Between PUs and SUs.
• Green Cognitive Small Cells
Source: X. Huang, T. Han, N. Ansari, “On Green Energy Powered Cognitive Radio Networks”, TR-ANL-2014-003, New Jersy Institute of Technology, 2014.
28
Green Energy Utilization in CRN (Challenges)
Simple decision policies are required to analytically balance energy consumption and harvesting.
Environment-aware green topology management and resource allocation schemes
(Artificial Intelligence for Green CR).
Mobile charging which relies on the wireless energy transfer.
Sharing/Trading sensing results is a form of power balancing.
Source: X. Huang, T. Han, N. Ansari, “On Green Energy Powered Cognitive Radio Networks”, TR-ANL-2014-003, New Jersy Institute of Technology, 2014.
29
New Trends in Cognitive Radio
Cognitive Radio in 5G
New Applications for CRNs
Green Cognitive Radio Networks
Cloud-based Cognitive Radio
Enhancement in CR MAC Protocols
Wireless Sensor Network-aided Cognitive Radio (CRSN)
Regulatory Aspects of CRNs
Cognitive Radio – Business Model
30
Cloud-based Cognitive Radio and Challenges
By using its capabilities of memory and computational capacity, Cloud computing
platform can enhance spectrum management, reduce energy consumption and
frequent hardware upgrades.
Development of spectrum management policies which describe the role of cloud
data centers in the cloud based CRN.
New protocols are required to manage the flow of information between various cloud
data centers and CRN nodes.
Security: CRN nodes need to know which data centers have access to the spectrum
info.
Compare the security and performance of commercial cloud providers in their ability
to provide effective services to the CRN nodes.
Audit the security and performance of cloud providers such that QoS for CRN nodes can
be met.
31
New Trends in Cognitive Radio
Cognitive Radio in 5G
New Applications for CRNs
Green Cognitive Radio Networks
Cloud-based Cognitive Radio
Enhancement in CR MAC Protocols
Wireless Sensor Network-aided Cognitive Radio (CRSN)
Regulatory Aspects of CRNs
Cognitive Radio – Business Model
32
CR MAC Challenges
MAC Design focusing on
energy.
Improve time synchronization
and network coordination for
SUs without dedicated CCC.
A need to develop more practical PU activity models by
considering the characteristics of
access technologies as well as types of
traffic.
Ensuring a reliable network coordination and reconfiguration
mechanism.
QoS-aware MAC
protocols
33
New Trends in Cognitive Radio
Cognitive Radio in 5G
New Applications for CRNs
Green Cognitive Radio Networks
Cloud-based Cognitive Radio
Enhancement in CR MAC Protocols
Wireless Sensor Network-aided Cognitive Radio (CRSN)
Regulatory Aspects of CRNs
Cognitive Radio – Business Model
34
Cognitive Radio Wireless Sensor Networks(CRSN)
CRSN Challenges
Low energy consumption spectrum
sensing design
Dynamic spectrum aware cluster formation and
maintenance techniques
Fault Tolerance
QoS
Security
• Clustered topology: Sensor nodes have a leader for a group called as cluster head which may perform operation of spectrum sensing and local spectrum bargaining.
• Heterogeneous and Hierarchical CRSN: Actor node equipped with more power so it can be works as relay node due to longer transmission range.
Source: Shailesh V. Kumbhar, Asha Durafe, “Cognitive Radio Sensor Network Future of Wireless Sensor Network”, International Journal of Advanced Research in Computer and Communication Engineering vol. 4, no. 2, 2015.
Military and Public Security, Home Appliances and Indoor Applications, Bandwidth-Intensive Applications, Real-Time Surveillance Applications, …
More about WSN
35
New Trends in Cognitive Radio
Cognitive Radio in 5G
New Applications for CRNs
Green Cognitive Radio Networks
Cloud-based Cognitive Radio
Enhancement in CR MAC Protocols
Wireless Sensor Network-aided Cognitive Radio (CRSN)
Regulatory Aspects of CRNs
Cognitive Radio – Business Model
36
Regulatory Agencies Involved in CR and Activities
Federal Communications Commission (FCC) • Report in 2002, 2006 and 2008. • FCC released the final rules for
“Unlicensed Operation in the TV Broadcast Bands” in 2010/2011.
Office of Communications (Ofcom)• In 2009 and 2015 reports, Ofcom
released a proposal which allowed unlicensed cognitive access to the spectrum.
• Ofcom suggested: (Master/Slave) (another policy for power limits)– Sensing– Geolocation– Beacon (not any more)
Conférence Européenne des Administrations des Postes et des Télécommunications (CEPT) – (CEPT’s SE43)
Fixed White Space DeviceOperates from a specified stationary location
Suitable for commercial Wi-Fi Hot-Spots, rural broadband distribution, or cellular-style installations.
Operate at comparatively higher power and with antennas mounted on a tall building or mast.
Due to its stronger signal, fixed devices are more strict on where and when the devices can operate.
Personal/Portable White Space Device
laptops, Wi-Fi access points, tablets, and smartphones.
Mode I: devices do not need geolocation capability or access to a database.
Mode II: devices must have geolocation capability (±50 m ) and the means to access a database for
list of available channels.
37
Spectrum Database (sample)
Information gathered from all TVWS devices:•The device’s geolocation•Its device type (Fixed, Portable Mode I, Mode II)•Its device identifier, which includes FCC ID and manufacturer serial no.•Data kept (30 days for portable, indefinitely for fixed)
38
Regulatory and Standardization(Challenges)
Roadmap for the time phased
transition to the new spectrum
management paradigm to consider
legacy issues and special band issues.
Issues which need to be
addressed by the regulatory bodies
be identified.
Harmonizing Terminology and
Reference Models.
Regulatory Dimensions to be Considered
(aspects of equipment,
responsibility, cognitive pilot
channels,…)
Potential Risks and Benefits that are related to CR and SDR technologies (Part of the SWOT
analysis)
Regulatory Framework to Encourage the Research and the
Development of CR. (for example,
allocating a block of spectrum for CR
control and enabling secondary licensing, …)
39
New Trends in Cognitive Radio
Cognitive Radio in 5G
New Applications for CRNs
Green Cognitive Radio Networks
Cloud-based Cognitive Radio
Enhancement in CR MAC Protocols
Wireless Sensor Network-aided Cognitive Radio (CRSN)
Regulatory Aspects of CRNs
Cognitive Radio – Business Model
40
Cognitive Radio – Business ModelKey Actors
Infrastructure Vendors
Regulators
Challenger Operators
Incumbent Operators
Content Providers
Equipment Vendors
41
Business Model for TVWS Network(SpectrumBridge®) – first FCC-certified geolocation database operator
Source: Yuan Luo, Lin Gao ; Jianwei Huang, “Business modeling for TV white space networks”, IEEE Communications Magazine, vol. 53, no. 5, pp. 82-88, 2015.
Spectrum Market(SpecEx)
• For underutilized Licensed TV channels
• The database acts as a spectrum broker to facilitate
the trading process
Information Market(White Space Plus)
• Unlicensed TV channels used by public and shared usage.
• Its quality are not guaranteed.• The database has more information regarding the
quality of TV channels• This information can be used by unlicensed WSDs to
improve their performance.
42
Cognitive Radio – Business ModelContent Provider - Business Model (sample)
• Value propositions: Offered Products / services.
• Customer segments: Target customer groups.
• Channels: Ch. for reaching the customer.
• Customer relationships: Types of relationships created with the different customer segments.
• Revenue streams: How the company earns money.
• Key resources: Assets depends on.
• Key activities: Most important activities the company must perform in order to operate successfully.
• Key partnerships: Key partners needed to create and deliver the value proposition.
• Cost structure: Describes the costs and their implications for the business model.
43
CR Promising Business Scenarios
Promising business
scenarios to be identified
Mobile operators
use TVWS to delay or replace
deployment of a more
dense networkMobile
operators using TVWS in countries
with very high
spectrum prices
Use TVWS for indoor systems
provided by local or mobile operators.
44
More …
Centralized/Distributed Algorithms for CRN Management.
CR I
mple
me
ntati
ons, T
est-
beds a
nd S
pectr
um
Meas
ure
me
nts.
CR Techniques for Offloading.
CRNs for IoT.
CR Satellite
45
Thank You
46
Backup Slides
Joseph Mitola and Cognitive Radio
The concept of CR was first proposed by Joseph Mitola III in a seminar at (the
Royal Institute of Technology in Stockholm) in 1998 and published in an
article by Mitola and Gerald Q. Maguire in 1999.
• Mitola later described CR as:“The point in which wireless Personal digital assistants (PDAs) and the related
networks are sufficiently computationally intelligent about radio resources and related computer-to-computer communications to detect user communications needs as a function of use context, and to provide radio resources and wireless services most
appropriate to those needs”
Back47
Cognitive Radio - Definition• International Telecommunication Union (ITU)
– ITU: A radio or system that senses, and is aware of, its operational environment and can dynamically and
autonomously adjust its radio operating parameters accordingly.
• Federal Communications Commission
– FCC: CR is a radio that can change its transmitter parameters based on interaction with the environment in
which it operated.
• National Telecommunication and Information Administration (NTIA)
– NTIA: A radio or system that senses its operational electromagnetic environment and can dynamically and
autonomously adjust its operating parameters to modify system operation, such as maximize throughput,
mitigate interference, facilitate interoperability, access secondary markets.
• Wireless World Research Forum
– WWRF: Cognitive radio employs a dynamic time-frequency-power based radio measurement and analysis of
the RF environment, to make an optimum choice of carrier frequency and channel bandwidth to guide the
transceiver in its end-to-end communication, with quality of service being an important design requirement.
48Back
• Spectrum sensing: Detecting unused spectrum and
sharing the spectrum without harmful interference with
other users.
• Spectrum decision: CR networks need to decide which
suitable spectrum bands can be used by secondary user.
• Spectrum mobility: Maintaining seamless
communication requirements during the transition to
better spectrum. Furthermore, to implant this process,
the spectrum mobility in CR networks is divided into two
parts, spectrum handoff and connection management to
compensate handoff delay.
• Spectrum sharing: Providing the fair spectrum scheduling
method among coexisting CR users.
Cognitive Radio Cycle
Back
50
Overview of Spectrum Sensing Methods
Sp. sensing Method
Disadvantages Advantages
Matched filter
Requires a priori info on PU transmissions, and extra hardware on nodes for synchronization with PUs.
Best in Gaussian noise. Needs shorter sensing duration (less power consumption).
Energy detection
Requires longer sensing duration (high power consumption). Accuracy highly depends on noise level variations.
Requires the least amount of computational power on nodes.
Feature detection
Requires a priori knowledge about PU transmissions. Requires high computational capability on nodes.
Most resilient to variation in noise levels.
Interference Temperature
Requires knowledge of location PU and imposes polynomial calculations based on these locations.
Recommended by FCC. Guarantees a predetermined interference to PU is not exceeded.
Spectrum Sensing
Cooperative
Detection
Non Cooperati
ve Detection
Energy Detection
Matched Filter
Detection
Cyclostationary Feature Detection
Interference based Detection
BackSource: Shailesh V. Kumbhar, Asha Durafe, “Cognitive Radio Sensor Network Future of Wireless Sensor Network”, International Journal of Advanced Research in Computer and Communication Engineering vol. 4, no. 2, February 2015.
51
Comparison of Cognitive Radio Paradigms
Underlay Overlay InterweaveNetwork Side Information: SUs know interference caused to PUs.
Network Side Information: SUs know channel gains, encoding techniques and possibly the transmitted data sequences of the primary users.
Network Side Information: SUs identify spectrum holes from which the primary users are absent.
Simultaneous Transmission: SUs can transmit simultaneously with PUs as long as interference caused is below an acceptable limit.
Simultaneous Transmission: SUs can transmit simultaneously with the PUs; to relay the PUs’ data sequences.
Simultaneous Transmission: SUs transmit simultaneously with a PU only when there is missed detection of the PU activity
Transmit Power Limits: Secondary user’s transmit power is limited by a constraint on the interference caused to PUs.
Transmit Power Limits: SUs can transmit at any power, the interference to primary users can be offset by relaying the PUs’ data sequences.
Transmit Power Limits: Secondary user’s transmit power is limited by the range of PU activity it can detect.
Hardware: SUs must measure the interference they cause to PUs’ receivers by either sounding and exploiting channel reciprocity or via cooperative sensing.
Hardware: SUs must also listen to PU transmissions. Encoding and decoding complexity is also significantly higher than other paradigms.
Hardware: Receiver must be frequency agile or have a wideband front end for spectrum hole detection.
Back
52
Cognitive Radio MAC Protocols - Example
CR MAC
Centralized
CSMA-MAC(Random Access – Single Radio)
IEEE-802.22(Time Slotted – Single Radio)
DSA driven(Hybrid MAC – Single Radio)
Distributed
Single Radio
SRAC , HC-MAC (Random Access )
OS-MAC (Hybrid MAC)
Multiple Radio
DOSS, DCA-MAC (Random Access)
C-MAC (Time Slotted)
SYN-MAC, Opportunistic MAC (Hybrid MAC)
• Time-slotted MAC protocols–Require network-wide
synchronization and operate by dividing time into discrete slots for both the control channel and data transmission.
• The random access protocols –Do not require time
synchronization, and are based on the CSMA principle.
• Hybrid MAC protocols–The control signaling occurs in
synchronized time slots and the data transmission follows random access channel schemes, or–Predefined durations for the
control/data frame – however, the access to the channel within each control or data transmission duration is completely random.
BackSource: Mahfuzulhoq Chowdhury, Asaduzzaman, and M. Fazlul Kader, “Cognitive Radio MAC Protocols: A Survey, Research Issues, and Challenges”, Smart Computing Review, vol. 5, no. 1, 2015.
C-MAC: Cognitive MACHC MAC: Hardware Constrained MACPOMDP: partially observable Markov decision processOP-MAC: Opportunistic MACSRAC: Single-Radio adaptive Channel DOSS: Dynamic Open Spectrum SharingDCA: Distributed Channel AssignmentDSA: Dynamic Spectrum Access
53
5G - Features
Source: http://parallelwireless/5GPP Vision - Radar diagram of 5G disruptive capabilities Back
54
WSN - Applications
Source: Tifenn Rault, Abdelmadjid Bouabdallah, Yacine Challal. Energy Efficiency in Wireless Sensor Networks: a top-down survey. Computer Networks, Elsevier, vol. 67, no. 4, pp. 104-122, 2014. Back
55
Classification of Energy-Efficient Mechanisms in WSN
Source: Tifenn Rault, Abdelmadjid Bouabdallah, Yacine Challal. Energy Efficiency in Wireless Sensor Networks: a top-down survey. Computer Networks, Elsevier, vol. 67, no. 4, pp. 104-122, 2014.
56
Cognitive Radio TestbedsCR Platforms• Lyrtech’s small form factor SDR development platform
– Flexible, powerful, extremely expensive, too complex for research.
• Microsoft Research SORA
• Eurecom Open-Air-Interface
– Support LTE, limited support, expensive)
• Ettus/NI USRP
– Relatively cheap, Wide use, poor RF performance
CR Software
• GNU Radio (most common used, written in C++ and python, supported by Ettus)
• OSSIE (by Virginia Tech, written in C++, …)
• IRIS (by Trinity College Dublin, written in C++, configuration method based on XML)• ASGARD (by Aalborg University in Denmark, written in C++, tackle the challenge
of next generation telecomm. systems using multi user MIMO and aggregated spectrum techniques.
Testbeds in CRN
• Gain CR product credibility
• Check realistic limitations for CR algorithms
• Check the real performance of CRNs
57
Multiple Dimensions of Spectrum Space
• Legacy sensing algorithms monitor and supervise the
spectrum through three conventional dimensions:
frequency, time and space domains.
• However, other degrees of freedom such as the used
code and the angle of arrival may be used.
Challenges
• Hybrid and new dimensions to create new spectrum
opportunities and optimize the utilization of spectral
resources.
Comparison of Transport Protocols in CRNs (single hop)
Source: X. Zhong, Y. Qin, and Li Li, “Transport Protocols in Cognitive Radio Networks: A Survey”, KSII Transactions on Internet and Information Systems (TIIS), vol. 8, no. 11, pp. 3711-3730, 2014.
58More
Comparison of transport protocols in CRNs (Multiple hop)
Back
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60
CR Attacks(1/2)
Back to Cognitive Radio Main Attacks
Sour
ce:
D. H
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J.M
. Cha
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61
CR Attacks(2/2)
Source:D. Hlavacek, J.M. Chang, A layered approach to cognitive radio network security: A survey, Computer Networks., 2014. http://dx.doi.org/10.1016/j.comnet.2014.10.001
Back to Cognitive Radio Main Attacks
National Telecommunication Institute Cognitive Radio Testbed (NTI-CRT)
NTI-CRT - Objective
• Objectives– To create a real national cognitive radio test-
bed. – Scientific and engineering understanding of
the technical constraints on the design and regulation
– Proposal for future cognitive radio systems operating on new bands.
Primary/Secondary Transmitters
Primary Transmitter (PTx)
Secondary Transmitter (STx)
Primary/Secondary Receivers
Primary Receiver (PRx)
Secondary Receiver (SRx)
Dispatcher
Spectrum Sensing USRP Spectrum Management USRP
National Telecommunication Institute (NTI) Cognitive Lab Architecture
NTI-CRT - Scenarios
Primary/Secondary Transmitters
Primary Transmitter (PTx)
Secondary Transmitter (STx)
Primary/Secondary Receivers
Primary Receiver (PRx)
Secondary Receiver (SRx)
Dispatcher
Spectrum Sensing USRP Spectrum Management USRP
National Telecommunication Institute (NTI) Cognitive Lab Architecture
• Sce 1: Prim Ch1 Sec Ch2 No Jamming• Sce 2: Prim Ch1 Sec Ch2 Jam Ch0• sce 3: Prim needs Ch1 Sec Ch2 Jam Ch1
– Dispatcher finds Jamming on the desired channel– Dispatcher moves Primary to another Jam free channel
(Ch0 as an example)
• Sce 4: Prim needs Ch2 Sec Ch2 Jam Ch1– Dispatcher finds Secondary on the desired channel– Dispatcher allocates Primary to the desired channel– Dispatcher moves Secondary to another Jam free channel
(Ch3 as an example)
• Sce 5: Secondary needs Ch2 Prim Ch2 Jam Ch1– Dispatcher finds Primary on the desired channel– Dispatcher rejects the Secondary Required Channel– Dispatcher moves Secondary to another Jam free channel
(Ch3 as an example)
• Sce 6: Jamming needs Ch0 Prim Ch1 Sec Ch0– Dispatcher finds Primary on the desired channel– Dispatcher rejects the Secondary Required Channel– Dispatcher moves Secondary to another Jam free channel
(Ch2 as an example)
• Sce 7: Jamming needs Ch2 Prim Ch1 Sec Ch2– Dispatcher finds Secondary on the desired channel– Dispatcher moves Secondary to another Jam free channel
(Ch0 as an example)
NTI-CRT – Scenario (1) – No jamming
NTI-CRT – Scenario (2) – Ch1 jamming
NTI-CRT – Scenario (3)(1/2) Prim needs Ch1 Sec Ch2 Jam Ch1
NTI-CRT – Scenario (3)(2/2) Prim needs Ch1 Sec Ch2 Jam Ch1
NTI-CRT – Scenario (4)(1/2) Prim needs Ch2 Sec Ch2 Jam Ch1
NTI-CRT – Scenario (4)(2/2) Prim needs Ch2 Sec Ch2 Jam Ch1
NTI-CRT – Scenario (5)(1/2) Prim needs Ch2 Sec Ch2 Jam Ch1
NTI-CRT – Scenario (5)(2/2) Prim needs Ch2 Sec Ch2 Jam Ch1
NTI-CRT – Scenario (6)(1/2) Jamming needs Ch0 Prim Ch1 Sec Ch0
NTI-CRT – Scenario (6)(2/2) Jamming needs Ch0 Prim Ch1 Sec Ch0
NTI-CRT – Scenario (7)(1/2) Jamming needs Ch2 Prim Ch1 Sec Ch2
NTI-CRT – Scenario (7)(2/2) Jamming needs Ch2 Prim Ch1 Sec Ch2