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MAINAK MUKHOPADHYAY et al: SOFTWARE RADIO FOR RURAL TELECOMMUNICATION

 

Same is visible from this figure which is the frequency response of the filter after the training mode. Comparing next figure with the frequency response of the channel it is seen that both are inverse of each other indicating that our equalizer has adapted to the channel well and is nullifying the effect of the channel which is also reflected from the error pattern after the slicer.

Here we would like to compare the output results of DFE with the one of the equalizer without decision feedback discussed in previous case. There the response of the channel had diverted away from the one desired much more as compared to this decision directed equalizer case.

Also from the simulation it was observed that what was the condition of the equalizer after 5000 samples in the case without decision feedback, decision feedback equalizer has gone up to 20000 samples before degrading to that level which is surely an advantage over the previous equalizers.

  

CONCLUSION

Adaptive Equalizers are the most important device to encounter unpredictable channel behaviuor for Software Defined Radio and must be augmented for any telecom device carefully especially for rural area where distance between base station and receiver may be huge, corresponds to a long distance channel of highly unpredictable behaviour for faithful transmission.

REFERENCES

  1. B Widrow, P E Mantey, L J Griffiths & B B Goode, Adaptive Antenna System, Proc IEEE, pp 2143- 2159, December 1967.

  2. Simon Haykin, Adaptive Filter Theory Communications Research Laboratory, McMaster University, Hamilton, Ontario, Canada.

  3. Tapan K Sarkar et al. Smart Antenna, Archtec House.

Authors

Moutusi Mondal, born in 1982 at Burdwan, West Bengal. Completed BE in Electronics & Telecommunication from Seemanta Engineering College, affiliated to North Orissa University. Presently working as Junior Project Assistant in the Dept. Electronics and Electrical Communication Engineering
at IIT Kharagpur.

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Mainak Mukhopadhyay, born in 1975 at Howrah. Passed AMIETE (Electronics & Telecommunication Engineering) in 1999. Obtained MTech in Microwave Engineering from University of Burdwan, West Bengal in April 2002. Joined Defence Research & Development Organization (DRDO) as Senior Research Fellow and spend 15 months there. Currently working as a Research (PhD) Scholar in the Dept. of Electronics& Electrical Communication Engineering at Indian Institute of Technology, Kharagpur. He has published more than 25 journal and conference papers and his field of research interests are Adaptive Array Antenna, Global Positioning System, Microwave Communication and Digital Signal Processing. He is Associate Member IETE, Associate of Institution of Engineers, India.

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Binay Kumar Sarkar, obtained BTech. in 1967, MTech in 1969 and PhD in 1981 from Indian Institute of Technology at Madras, Kharagpur and Bombay respectively. He joined Tata Institute of Fundamental Research (TIFR), Bombay, as a Scientific Officer where he worked on PIN diode and gas discharge based

  

microwave control circuits and CW Radars for speed monitoring and projectile velocity measurement during the period 1969 to 1985. Subsequently, he was transferred to the Society for Applied Microwave Electronics Engineering and Research (SAMEER) under Ministry of Information Technology, Govt of India and he retired as director from there. At present, he is holding the post of ISRO Chair Professor of IIT Kharagpur. He has been working on Microwave Semiconductor devices and its applications, antenna and microwave instrumentations based on radar systems during the last 30 years. He has published more than 150 journal and conference papers. He is Senior Member of IEEE, USA and member, Society of EMC Engineer, India.

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Ajay Chakraborty, born in 1953 at Kolkata, India, he received the BTech MTech and PhD degrees from the Indian Institute of Technology, Kharagpur, in 1975, 1977 and 1982 respectively. He joined the faculty of the E & ECE Department at IIT Kharagpur in 1980. He worked as a visiting Assistant Professor at Syracuse University from Aug. 1989 to May 1990. His current research interests are antenna pattern synthesis, slot arrays feed networks for phased arrays, and ESD studies. Currently, he is a Professor in the Department of Electronics & Electrical Communication Engineering at the Indian Institute of Technology, Kharagpur and also Chairman of Kalpana Chawla Space Technology Cell of IIT Kharagpur. He has published more than 150 journal and conference papers and guided 20 PhD students as research guide. He is Senior Member of IEEE, USA and member Society of EMC.
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