1. 7/5/2014
Electrical Department Institute of Space
Technology, Islamabad 1

2. Presented by:
Wardah & Mariam
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Electrical Department Institute of Space
Technology, Islamabad

3.  Why IEEE 802.22?
 Television WS: A New Hope
 Cognitive Radio
 IEEE 802.22 Standard
 Ongoing Projects
 Future Scope
 Conclusion
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Electrical Department Institute of Space
Technology, Islamabad

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Electrical Department Institute of Space
Technology, Islamabad

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Technology, Islamabad

6. Wireless accessibility to underserved areas
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Electrical Department Institute of Space
Technology, Islamabad

7.  Spectrum is limited !!!
 Underutilized spectrum
 Fixed spectrum assignment to primary users
 Inefficient usage necessitates the development
of dynamic spectrum access techniques
 Customer Premise Equipments (unlicensed)
are allowed to use the temporarily unused
licensed spectrum
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8.  Vacant frequencies made available for unlicensed use
at locations where spectrum is not being used by
licensed services.
 This spectrum is located in the VHF (54-216 MHz) and
UHF (470-698 MHz) frequency bands.
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Electrical Department Institute of Space
Technology, Islamabad

9.  “Radio in which communication systems are aware of their
environment and internal state and can make decisions about their
radio operating behavior based on that information and
predefined objectives. The environmental information may or may
not include location information related to communication
systems” -SDR Forum
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Electrical Department Institute of Space
Technology, Islamabad

10.  Ability to sense and gather information
 Tx Frequency
 BW
 Power
 Modulation
 Customer Premise Equipment identify the best
available spectrum
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Electrical Department Institute of Space
Technology, Islamabad

11.  Rapidly adapting operational parameters
according to the sensed information
 Achieving optimal performance
 Tx power
 Frequency
 Modulation scheme
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Technology, Islamabad

12. Sensing
•CR enables Customer Premise Equipment to
sense available spectrum
Selecting
•Selects Best available channel
Coordination
•Coordinates spectrum access with other
Customer Premise Equipments
Evacuation
•Evacuates the channel when PU reclaims the
spectrum right
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Technology, Islamabad

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Technology, Islamabad

14.  Aimed at using cognitive radio (CR) techniques to
allow:
 sharing of geographically unused spectrum allocated to the
television broadcast service
 on a non-interfering basis
 to bring broadband access to low population density areas
(rural environments)
 The IEEE 802.22, the Working Group on Wireless
Regional Area Networks ("WRANs") is developing a
wide variety of standards to enable spectrum sharing
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Technology, Islamabad

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• Wireless Regional Area
Networks (WRANs)
- Wireless broadband access (e.g.
Rural areas)
• Entities:
-Base Station
-Customer Premise Equipment
• Topology-
-Point-to-multipoint (P-MP)
-Master/Slave relationship
• Service Capacity
-upto 24 Mbps
• Service coverage
-upto 100 km
Electrical Department Institute of Space
Technology, Islamabad

16.  Base Station
 Fixed location
 Decides channel availability
 Makes final decision
(availability of TV channels)
 Client Station
 Customer Premise
Equipment (CPE)
 Fixed location
 Reports spectrum sensing to
Base Station (BS)
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Technology, Islamabad

17.  Specification:
 Multiple Access: OFDMA
 Frequency Range: 54-862 MHz
 Bandwidth: 6 MHz, 7 MHz, 8 MHz
 Adaptive Modulation: QPSK, 16-QAM, 64-QAM
 Capacity: 24 Mbps
 Spectral Efficiency: 4 b/s/Hz
 Coding: Convolution Code (mandatory)
 Tx/Rx Antenna: BS uses Omni-directional antenna /
Customer Premise Equipment uses
directional antenna
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18.  Specification:
1. Superframe and Frame
1. Synchronized timing
structure
2. Better incumbent
protection
3. Better Self co-existence
4. Frame:
 Superframe Preamble
 Frame Preamble
 Superframe Control Header
2. Cognitive functionality
1. Spectrum Sensing
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21.  Fast Sensing: 1 ms
 Fine Sensing: 25 ms
 Sensing is required:
 Analog TV
 Digital TV
 Wireless microphones
 Sensing period : 30 seconds
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• Sensing mode & Signal type:
• Signal Present decision: Check if the
signal specified is present in the
channel
• Confidence Metric: Measure of the
confidence that spectrum sensor has
in Signal Present Decision
• Field Strength Estimate: Estimate of the
EM strength of the signal
• FS Estimate Accuracy: Measure of the
accuracy of FS Estimate
Electrical Department Institute of Space
Technology, Islamabad

23.  Comparison of detection
statistics with pre-
determined threshold 𝛾
 Good detector
 High detection Probability 𝑃 𝐷
 Low false alarm 𝑃𝐹
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𝐻0: 𝑦 𝑡 = 𝑛 𝑡
𝐻1: 𝑦 𝑡 = ℎ𝑥 𝑡 + 𝑛 𝑡
T =
1
𝑁
𝑡=1
𝑁
𝑦 𝑡 2
𝑃𝐹 = Pr 𝑇 > 𝛾 𝐻0
𝑃 𝐷 = Pr(𝑇 > 𝛾|𝐻1)
Electrical Department Institute of Space
Technology, Islamabad

24. 𝑅 =
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α11 ⋯ α 𝑛1
⋮ ⋱ ⋮
α1𝑛 ⋯ α 𝑛𝑛
T =
𝑇1
𝑇2
𝑇1: 𝑆𝑢𝑚 𝑜𝑓 𝑚𝑎𝑔𝑛𝑖𝑡𝑢𝑑𝑒 𝑜𝑓 𝑎𝑙𝑙 𝑒𝑙𝑒𝑚𝑒𝑛𝑡𝑠
𝑇2: 𝑆𝑢𝑚 𝑜𝑓 𝑚𝑎𝑔𝑛𝑖𝑡𝑢𝑑𝑒 𝑜𝑓 𝑑𝑖𝑎𝑔𝑜𝑛𝑎𝑙 𝑒𝑙𝑒𝑚𝑒𝑛𝑡𝑠
y(n) =
𝑤 𝑛 , 𝑇1 = 𝑇2
𝑥 𝑛 + 𝑤 𝑛 , 𝑇1 ≠ 𝑇2
 Test Statistic
Electrical Department Institute of Space
Technology, Islamabad

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Electrical Department Institute of Space
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26.  Spectrum Sensing issues
 Synchronization issues
 Multi-dimensional Spectrum awareness
 Detection Frequency and Time
 Hardware based high speed Signal Processors
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Technology, Islamabad

27.  Smart Grid
 Smart Traffic Management
 Environment Monitoring
 Broadband Service extension
 Temporary Broadband
Infrastructure
 Remote Medical Service
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Technology, Islamabad

28. 7/5/2014 28
Smart Traffic Management
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Technology, Islamabad

29.  IEEE 802.22 is required to reuse the fallow TV spectrum
without causing any harmful interference to incumbents
(i.e., the TV receivers).
 Cognitive radio techniques are of primary importance in
order to sense and measure the spectrum and detect the
presence/absence of incumbent signals.
 Base Station and Customer Premise Equipment has Master
Slave N/w Architecture
 Spectrum sensing is periodically done by BS and CPE
 CPE Reports spectrum sensing to Base Station (BS)
 BS makes the final decision
 CPE vacates the channel if primary
 users signal is detected
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Technology, Islamabad

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31. Research Papers:
[1]. Carlos Cordeiro, KiranChallapali, DagnachewBirru, and SaiShankar N
“IEEE 802.22: The First Worldwide Wireless Standard based on Cognitive
Radios” First IEEE International Symposium on New Frontiers in Dynamic
Spectrum Access Networks, 2005.
[2]. Carl R. Stevenson, Gerald Chouinard, ZhongdingLei, WendongHu,
Stephen J. Shellhammer and Winston Caldwell “IEEE 802.22: The First
Cognitive Radio Wireless Regional Area Network Standard” IEEE
Communications Magazine, January 2009.
[3]. IEEE 802.22 Working Group on Wireless Regional Area Networks,
http://www.ieee802.org/22/.
[4]. H. Urkowitz, “Energy detection of unknown determin- istic signals,” Proc.
of IEEE, pp. 523–531, Apr. 1967.
[5]. Beibei Wang and K. J. Ray Liu, “Advances in Cognitive Radio Network: A
Survey” IEEE Journal Vol. 5, NO.1, Feburary 2011
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Technology, Islamabad