Open Science Journal Jour nal of Electrical and Electronic Engineering 2014; 1(1): 1-5 Published online June 10, 2014 (http://www.openscienceonline.com/journal/j3e)
Improvement of BER on different fading channel using IEEE 802.22 Standard Priti Subramanium1, Rajeshree D. Raut2 1 2
Department of Computer Science & Engineering, SSGB COET, Bhusawal, India Department of Electronics Engineering, RCOEM, Nagpur-13, India
Email address
[email protected] (P. Subramanium),
[email protected] (R. D. Raut)
To cite this article Priti Subramanium, Rajeshree D. Raut. Improvement of BER on Different Fading Channel Using IEEE 802.22 Standard. Open Science Journal of Electrical and Electronic Engineering. Vol. 1, No. 1, 2014, pp. 1-5.
Abstract The worldwide first application of cognitive radio (CR) networks in unlicensed television broadcast bands is IEEE 802.22 wireless regional area network. This paper introduces the implementation of IEEE 802.22 Wireless Regional Area Network (WRAN) for broadband Internet access in urban areas. We have investigated how CR through dynamic spectrum access facilitates the efficient use of underutilized spectrum white spaces. We have analyzed a coverage planning for wireless regional area network and compared it with different fading channels such as Additive White Gaussian Noise, Rayleigh & Rician channels.
Keywords WRAN, AWGN, CR, MIMO
1. Introduction Most of the useful radio spectrum is currently occupied by licensed users such as GSM, WCDMA and TV [1]. However, studies show that RF spectrum is not properly utilized in sub-urban and rural areas [1]. CR is considered as most emerging technology capable of dynamically accessing the underutilized spectrum (white spaces) without causing harmful interference to incumbent users and other secondary users [1].
2. The TV White Space Spectrum In the United States, 408 MHz of spectrum from 54 MHz to 806 MHz is allocated for TV. Currently, 108 MHz of that spectrum is being redeveloped for commercial operations through auctions and for public safety applications. The remaining 300 MHz of this radio spectrum will remain dedicated for over the air Television operations. However, throughout the US, portions of that 300 MHz resource remain unused. The amount and exact frequency of unused
spectrum varies from location to location. These unused spectrums are referred to as TV White Space. Larger amounts of unoccupied TV White Space spectrum are available in low population density or rural areas that tend to be underserved with other broadband options such as Digital Subscriber Line or cable. This makes this spectrum of particular interest for Wireless ISP operations in rural areas where the population is normally unserved or underserved with broadband access. Each available Television channel provides 6 MHz of spectrum capacity that can be used for broadband connectivity. The amount and exact frequency of unused spectrum varies from location to location. These unused spectrum are referred to as TV White Space. Larger amounts of unoccupied TV White Space spectrum are available in low population density or rural areas that tend to be underserved with other broadband options such as Digital Subscriber Line or cable. This makes this spectrum of particular interest for Wireless ISP operations in rural areas where the population is normally unserved or underserved with broadband access. Each available television channel provides 6 MHz of spectrum capacity that can be used for broadband
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Priti Subramanium and Rajeshree D. Raut: Improvement of BER on Different Fading Channel Using IEEE 802.22 Standard
connectivity. This increased spectrum capacity provides the opportunity for new broadband applications to transmit video, voice or data services. Following are some likely potential uses: State & Local Government – Local government and school districts can perform data transfer at a fraction of the cost of leased lines. Service Provider – A community can be connected to provide Internet access to business and residential subscribers who are currently beyond the reach of Digital Subscriber Line services. Enterprises - A manufacturing plant, transportation hub, a power plant could use available Television White Space spectrum to help implement wireless data transfer and/or video surveillance for security of their facilities. These frequency bands are attractive to broadband users for the following reasons: • Their is availability of large amount of spectrum that can be used to provide connectivity. • The Propagation qualities that provide for Line of Sight (LOS), and Non Line of Sight (NLOS) performance. • The Larger coverage areas due to long range propagation of signal at these frequencies. • The FCC has decided to support the use of TV White Space as a means to provide broadband connectivity to rural areas in the United States by providing unlicensed access to the unused bands within TV White Space spectrum. The signals must not interfere with broadcast digital TV (DTV) transmissions or other licensed users in these bands. The FCC has recently completed testing with prototype equipment from a number of manufacturers. The testing was intended to collect data to enable the FCC to write rules for use of unlicensed devices in this spectrum. Currently, the TV White Space spectrum is used by the following application: • Broadcast TV – Operators that broadcast TV content to a region that use fixed outdoor signal sources to reach fixed indoor and outdoor antennas at business and residential locations. • Low power wireless devices –Users that broadcast audio content to a local area using nomadic indoor or outdoor microphones or other low power operations related to broadcast and non- broadcast uses. It can be either permanent locations such as a school or house of worship, or a temporary event such as a community event or sporting event.
3. The Fixed TV White Space Opportunity for Providers Wireless Internet Service Providers (WISP) in the United States offer cost effective, reliable broadband connectivity to areas where DSL or other wireline or wireless based solutions are not available or not cost effective. Using the unlicensed spectrum such as 900 MHz, 2.4 GHz and 5 GHz, these entrepreneurs are able to provide data, voice and video connectivity, enterprise and residential users in their
community. Thousands of WISPs exist in the US today, purchasing broadband connectivity in bulk and then wirelessly backhauling that connectivity to a distribution network in a previously underserved location. The availability of TV White Space spectrum present an opportunity for these service providers to construct the connectivity needed in suburban and rural locations for the following reasons: • Some Additional Connectivity to Existing or New Subscribers – Enables more channels to better serve existing customers and add new customers in capacity constrained areas. • Additional Applications – More bandwidth enables current customers to add more capabilities to their existing connections. For eg, a network operator with connectivity for data transfer will now have sufficient bandwidth for video surveillance of remote areas. • Data connectivity with broadband performance Ability to offer services with competitive throughput performance characteristics. Some subscribers are limited to sharing 4 Mbps of throughput, these subscribers can grow their businesses and provide improved connectivity with 1 to 2 Mbps per subscriber. • Wider Coverage Area – Where current LOS coverage areas are limited to 2 mile range, service providers can now reach areas with LOS and NLOS coverage to 5 miles or more. • Simple installation – The “all outdoor” solution is easy to install and does not require the cost of a building or environmentally controlled compartment at the AP tower location. • Network Security - Positive authentication of users to reduce unauthorized non-paying access and protection of over-the-air signal integrity.
4. Motorola Activities in TV White Space Motorola is a member of the Wireless Innovation Alliance (WIA), which is a coalition of technology innovators, Public interest advocates, and higher education organizations that are dedicated to the innovation and the unlimited possibilities of unlicensed and currently unused white space spectrum. WIA and its member organizations believe that with proper development and deployment, innovative TV White Space broadband solutions will enable the delivery of new communication services, particularly wireless broadband, to millions of underserved Americans and business enterprises. Almost four years ago, the Federal Communications Commission (FCC) began considering rules to allow the use of much needed and currently vacant spectrum between broadcast channels by unlicensed devices. In January 2008, the FCC greatly advanced its efforts by beginning a second round of testing of developmental devices. The testing and
Open Science Journal of Electrical and Electronic Engineering 2014; 1(1): 1-5
information gathering process undertaken by the FCC is designed to provide information that will serve as a foundation for rules ensuring protection of television channels while unleashing the benefits of unlicensed TV White Space device use in unused channels within this spectrum. The FCC has decided to adopt the rules and requirements for use of this spectrum, manufacturers can develop commercially available devices and bring a new generation of broadband opportunities to the American public.
then ranks available channels per allowable RF power prior to active sensing. This is what was implemented in a demonstration to the FCC in August, 2007. Process is illustrated in Figure 2.
6. IEEE 802.22 – PHY Features •
• • •
Fig.1. Motorola’s Mobile and Fixed TV White Space Use Cases
5. Geolocation Motorola uses a geo-location database to determine what spectrum is available in a user’s given area. Licensed systems, including land mobile in the 470-512 MHz band and television stations.
PHY Transport - 802.22 uses Orthogonal Frequency Division Multiplexing (OFDM) as transport mechanism. Orthogonal Frequency Division Multiple Access (OFDMA) is used in the Upstream. Modulation - QPSK, 16-QAM and 64-QAM supported . Coding – Convolutional Code is mandatory. Either Turbo, LDPC or Shortened Block Turbo Code can be used for advanced coding. Pilot Pattern - Each OFDM / OFDMA symbol is divided into sub-channels of 28 subcarriers of which 4 are pilots. Pilot carriers are inserted once for every 7 subcarriers. Pilots cycle through all 7 subcarriers over 7 symbol duration. Frequency domain interpolation is required because of low Doppler spread in TV bands.
7. Simulation Parameters 1. Input Image = 12800 Bits. 2. Modulation technique used = QAM, DPSK, PSK. 3. Channels used =AWGN, Rayleigh, Rician. 4. IFFT size =2048 5. Turbo coding rate= 1/2. 6. Max Doppler Shift = 100. 7. Delay time First delay path = 0, Second delay path = 1x10-8.
8. Steps involved in Simulation Model
Fig.2. Simple TV White Space Operation.
By knowing its location, querying the database, and being programmed with FCC set protection requirements, a Television White Space system can determine what channels are available while still protecting licensed or incumbent operations. DTV station availability varies mostly by location. Where a frequency band may be used in one location, there may be many large areas where this frequency is not used and available for use for broadband connectivity. Motorola’s TV White Space solution, with the ART (Adaptive Radio Technology), downloads position, power, and channels of nearby primary users (e.g. DTV) from the FCC database. The Adaptive Radio Technology
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Transmitter Section 1. Data inputs in terms of bits or image. 2. Turbo encoder. 3. Modulation used 64 QAM, 16 QAM, and 4 QPSK. 4. Serial to Parallel Converter. 5. IFFT (Inverse Fast Fourier Transform). 6. Parallel to Serial Converter. 7. Channel used AWGN, Rayleigh, Rician. 8. Noise is introduced due to channel. Receiver Section 1. 2. 3. 4. 5. 6.
Serial to Parallel Converter. Fast Fourier Transform. Parallel to Serial Converter. Demodulation. Turbo Decoder. Received data bits or image.
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Priti Subramanium and Rajeshree D. Raut: Improvement of BER on Different Fading Channel Using IEEE 802.22 Standard
9. Results & Discussions
References
1. Table of matlab simulation. Sr.
1 2 3
Channels
Modulation 64 QAM
Modulation 16 QAM
Modulation 4 QPSK
AWGN
SNR=12db BER=0.0113
SNR=16 db BER=5.4x10-4
SNR= 10 db BER=3 x10-3
Rayleigh
SNR=20db BER=0.327
SNR=20 db BER=0.390
SNR= 20 db BER= 0.086
Rician
SNR=14db BER=0.016
SNR= 18 db BER=1.6 x10-3
SNR= 12db BER=1.5x10-4
This table shows the matlab simulation results. In this paper we are using channels such as AWGN, Rayleigh, Rician. For different modulation techniques such as 64 QAM, 16 QAM, 4 QPSK used in IEEE 802.22 we are getting results in terms of signal to noise ratio (SNR) & bit error rate (BER). From these results we analyzed that in AWGN and Rician channel for low SNR we are get better BER. For example in AWGN channel for 16 QAM we are getting SNR=16 db & BER= 5.4x10-4 and for 4 QPSK we are getting SNR= 10 db & BER 3x10-3. Similarly for Rician channel for 16 QAM we are getting SNR=18 db & BER=16x10-3 and for 4 QPSK we are getting SNR= 12 db & BER= 1.5x10-4. Whereas in Rayleigh channel for higher SNR we are not getting better BER. This problem which has occurred due to fading channels can be solved by using MIMO ( Multiple input multiple output ) antennas.
[1]
Carlos Cordeiro, Kiran Challapali, and Dagnachew Birru, “ IEEE 802.22: An introduction to the First Wireless Standard based on Cognitive Radios ”.
[2]
Raed Al-Zubi, Mohammad Z.Siam, and Marwan Krunz, “ Coexistence Problem in IEEE 802.22 Wireless Regional Area Networks ”.
[3]
Santa Rahman, Nahid Hossain, Nizam Sayeed, M. L. Palash, “ Comparative Study between Wireless Regional Area Network and Wimax and Coverage Planning of a wireless Regional Area Network Using Cognitive Radio Technology ”.
[4]
Spyridon K.Chronopoulous, G.Tatis, P. Kostarakis “ Turbo Coded OFDM with Large number of Subcarriers ” Journal of Signal and Information Processing, 2012, 3 ,161-168.
[5]
Indejeet Kaur, Dr.Y.K.Mathur “ Improving BER using turbo codes in OFDM systems ” International Journal of Scientfic & Engineering Research,Vol 3,Issue 7 July 2012.
[6]
M. K. Gupta, vishwas Sharma “ To improve BER of turbo coded OFDM channel over noisy channel ” in Journal of Theoretical and applied Information Technology © 2005 2009 JATIT.
[7]
Liu Na Shi Wenxiao Wu Jiang “A Model of Turbo Code Based on OFDM-CDMA” in IEEE journal of 2006.
[8]
Md. Dulal Haque1, Shaikh Enayet Ullah2, and Md. Razu Ahmed3 “ Performance evaluation of a wireless Orthogonal Frequency Division Multiplexing system under various concatenated FEC channel-coding schemes ” in Proceeding of 11th International conference on Computer and Information Technology (ICCIT 2008) 25-27 December, 2008, Khulna Bangladesh.
[9]
D. Rajaveerappa, Abdelsalam Almarimi “ RSA/Shift Secured IFFT/FFT Based OFDM Wireless System ” in 2009 Fifth International Conference on Information Assurance and Security.
10. Conclusion This paper introduces the implementation of IEEE 802.22 Wireless Regional Area Network (WRAN) for broadband Internet access in urban areas. We have analyzed a coverage planning for wireless regional area network and compared it with different fading channels such as AWGN, Rayleigh & Rician channels. From the simulation results, we conclude that in fading channels such as AWGN and Rician channels we get better results for less SNR, but in Rayleigh channels due to NLOS we are not getting better results as compared to AWGN & Rician. This problem which has occurred due to fading channels can be solved by using MIMO ( Multiple input multiple output ) antennas.
Acknowledgment This work is supported by my guide Dr. Rajeshree D. Raut. The authors also gratefully acknowledge the helpful comments and suggestions of the reviewers, which will improve the presentation. This work is supported by my guide Dr. Rajeshree D. Raut. The authors also gratefully acknowledge the helpful comments and suggestions of the reviewers, which will improve the presentation.
[10] Arun Agarwal, S. K. Patra, Senior Member IEEE “ Performance prediction of OFDM based Digital Audio Broadcasting system using Channel protection mechanisms ” in IEEE journal © 2011. [11] Lou I Ilunga, Research Work on “Adaptive, turbo coded OFDM” © 2005. [12] Haixa Zhang, Feng Zhao, Dongfeng Yuan, Mingyan Jiang, “ Performance of turbo code an WOFDM system on rayleigh fading channels,” Proceedings, IEEE, vol. 2, pp.1570-1573, Sept 2003. [13] J.W. Blakert, E.K. Hall, S.G. Wilson, “ Turbo code termination and interleaver conditions,” Electronics Letters, Vol. 31, Issue 24, 1995, pp. 2082-2084. [14] Ramjee Prasad, “ OFDM for Wireless communications systems ”, Artech House Publishers, 2004. [15] L. Hanzo, M. Munster, B.J. Choi, T. Keller, “ OFDM & MCCDMA for Broadband Multiuser communications, WLANs and Broadcasting ” Multiuser Communications WLANs and Broadcasting” John Wiley Publishers, 2003.
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Biography Priti Subramanium was born on 20.11.1976, in 1999 completed my bachelor‘s degree in Electronics & Telecommunication Engineering, from Government College of Engineering, Aurangabad, M.S., India. I Completed my Masters in Digital Electronics in 2007. Presently Pursuing Ph. D in Electronics and my research has made significant contribution in the field of Bit Error Control Coding in Adaptive Environment. Having an experience of 13 years, currently is actively associated with Shri Sant Gadge Baba College of Engineering, as the Assistant Professor in department of Computers Science & Engineering.
Rajeshree D. Raut was born on Aug. 2nd, 1976 completed her bachelor‘s degree in Electronics & Telecommunication Engineering, from Government College of Engineering, Amravati, M.S., India. She completed her Masters in Electronics from the same institute in 2002. She is Ph. D in Electronics and her research has made significant contribution in the field of Error Control Coding in Cognitive Environment. Having an experience of 13 years, she currently is actively associated with Research & Development Cell at Shri Ramdeobaba Kamla Nehru Engineering College, as the Associate Dean R & D. Dr. Raut is also crowned by “Shiksha Rattana Award”, for Excellence in technical Education, conferred by the IIFS, Delhi and Best Citizen of India Award for her research Contribution in the Field of Cognitive Radio.
