Nikookar Presentation Hermes 4Oct2013 · Wireless Systems based on wavelets Dr. Homayon Nikookar...

H.Nikookar, Wavelet Radio, Presentation at Hermes Partnership Meeting, 4 Oct. 2013, Amsterdam.

Wavelet Radio:

Adaptive and Reconfigurable Wireless Systems based on wavelets

Dr. Homayon Nikookar

Microwave Sensing Systems and Signals Section

Faculty of Electrical Eng., Mathematics and Computer Science

Delft University of Technology

Delft, The Netherlands.

[email protected]

H.Nikookar, Advanced Wireless Technologies and Systems (AWTS), Presentation at Twente University, June 29, 2007.H.Nikookar, Wavelet Radio, Presentation at Hermes Partnership Meeting, 4 Oct. 2013, Amsterdam.

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Contents:

• Applications of wavelet in Wireless Communications: the Needs, Means

• Wavelet Radio Communication System

• Some research results and comparison with OFDM

• Wavelet-based spectrum sensing (for cognitive radio)

• Areas of wireless system design where wavelet architecture can be readily apply

• Future Research


Global Mobile Data Traffic Growth (Mobile traffic will grow by 18 times from 2011 to 2014). Notations in the left hand side figure: EB - Exabytes (1018 bytes).

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Application of Wavelets in Wireless Communications

Source: Filter To The Home (FTTH), 2012


The Need

• High speed, energy efficient, green technologies that optimize radio resources (power and spectrum) while guaranteeing a desirable quality of service.

• Wireless systems operate in harsh environments under dynamic conditions with frequent changes in the propagation environment and user requirements.

• These trends point to flexible, reconfigurable systems that can adapt to its radio neighbourhood.

The Means

• Existing wireless systems and services are based on Fourier transform.

• In comparison to the Fourier transform the recently formulated theory of wavelets offers many advantages for the design of wireless communications:

- Wavelets characterize signals with adaptive time-frequency resolution.

- Wavelet radio can handle large volumes of data under severe constraints of interference and resources such as power and bandwidth.

- By careful adaptation of the system parameters according to the radio environment the operation of the wavelet based radio is optimized to save valuable resources.

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Wavelet Radio Communication System

• Conventional wireless systems use Fourier bases while wavelets(waveforms of limited duration) provide promising potential advantages and applications.

• The main property of wavelets for these applications is their ability and flexibility to characterize signals with adaptive time-frequency resolution.

• Wavelet based wireless communication system adaptively reconfigures to maximize resource utilization and interference mitigation. (application in Multi-radio)

• Wavelets are uniquely qualified to address the objectives of intelligent communication design because of their flexible and adaptable nature.

• Their characteristics can be widely customized to fulfill the requirementsof intelligent wireless communication systems.


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Range of Wavelet Applications for Wireless Communication

Source: H. Nikookar, Wavelet Radio: Adaptive and Reconfigurable Wireless Systems based on Wavelets, Cambridge University Press, 2013.


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Wavelet Radio GoalsSource: H.Nikookar, Wavelet Radio: A future vision for wireless communications, Book chapter, Globalization of Mobile and Wireless

Communications today and in 2020, Springer, 2011.


8OFDM Modulator (top) and Demodulator (down).


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Wavelet Packet Modulator and Demodulator. Source: H. Nikookar, Wavelet Radio, Cambridge University Press, 2013.


• Synchronization issues of Wavelet radio (time, freq. phase noise) and comparison with the OFDM

• Peak-to-average power ratio (PAPR) of wavelet Packet Modulation

• Wavelet based spectrum sensing for cognitive radio

• Optimal wavelet design for cognitive radio and for minimum interference due to timing error

10Constellation of received signal in the presence of timing error. Source: H. Nikookar, Wavelet Radio, Cambridge University Press, 2013.


• Peak-to-average power ratio (PAPR) of wavelet Packet Modulation

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0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

10−1

100

Power [dB]

CD

F

distribution of WPM powerGaussian distributionRayleigh distributionChi−square distribution

Cumulative Density Function (CDF) of the power of wavelet packet modulation signals. Source: H. Nikookar, Wavelet Radio, Cambridge University Press, 2013.

H.Nikookar, Wavelet Radio, Presentation at Hermes Partnership Meeting, 4 Oct. 2013, Amsterdam.

System model of the Wavelet Radio. Transmitter: The major blocks include the spectrum and channel state estimator, adaptive pulse shaper (Wavelet transform and transmission waveform shaping) and modulator. Receiver: The major blocks include the Signal decorrelator, integrator and detector.

Source: H. Nikookar, Wavelet Radio: Adaptive and Reconfigurable Wireless Systems based on Wavelets, Cambridge University Press, 2013.


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Spectrum sensing and dynamic spectrum access.


Wavelet based spectrum sensing for cognitive radio

Wavelet Packet Spectrum Estimation (WPSE). Source: H. Nikookar, Wavelet Radio, Cambridge University Press, 2013.

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Performance (ROC-Receiver Operating characteristics) evaluation method in Wavelet Packet Spectrum Estimation (WPSE).Source: H. Nikookar, Wavelet Radio, Cambridge University Press, 2013.


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Receiver Operating Characteristic (ROC) of WPSE for different wavelet families.Source: H. Nikookar, Wavelet Radio, Cambridge University Press, 2013.


• Wavelet design for spectrum sensing of Cognitive Radio

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0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

−25

−20

−15

−10

−5

0

Normalized Frequency(xπ rad/sample)

Ma

gn

itud

e (

dB

)

LPF (Designed Wavelet,K−regularity =7,

Transition Band = 0.2π)

HPF (Designed WaveletK−regularity = 7,

Transition Band = 0.2π)

LPF (Coiflet−5)

HPF (Coiflet−5)

LPF (Daubechies 15)

HPF (Daubechies 15)

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1−60

−50

−40

−30

−20

−10

0

Normalized Frequency (x π rad/sample)

Po

we

r /

Fre

qu

en

cy (

dB

/ ra

d/s

am

ple

)

Designed wavelet (Length=30 K−regularity=7 TransitionBand=0.2π)

Daubechies−15

Symlet−15

Coiflet−5

Freq. response of wavelet low-pass and high-pass filters. Source: H. Nikookar, Wavelet Radio, Cambridge University Press, 2013.

Spectrum shaping with WPM carriers based on wavelets.Source: H. Nikookar, Wavelet Radio, Cambridge University Press, 2013.


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Areas of wireless system design where wavelet architecture can be readily apply:

• Modeling of time-variant wireless channels

• Multiple access communications

• Green radio communications (energy efficient transmission optimally utilizing available resources and minimize power consumption)

• Application of Wavelet Technology in Cognitive and Cooperative Wireless Communications

• Wavelet based MIMO.


Future Research: Applying Wavelet technology to cooperative Wireless

Sensor Networks

• Advanced Signal Processing schemes and architectures for handling sensor data (Process Industry, Transport, M2M, IoT)

• Cooperative radio systems for climate monitoring, early warning of floods and storms,…

• Green radio sensors networks for structural health monitoring, for smart power grid

• Self reconfigurable and self organized radio networks for disaster scenarios (earthquake, or other natural catastrophes)

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Book Website:

www.cambridge.org/9781107017801


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Thank you for your attention.

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