Abstract. The focus of this paper is
directed towards the development and investigation of efficient technique for
narrow-band mitigation for signal construction based on OFDM signals (orthogonal
frequency division multiplexing) and error-correcting codes. In paper the
frequency-domain algorithms for that noise mitigation are proposed. The analysis of
noise-immunity for these signal constructions is implemented for convolutional
code with code-rate 1/2 and for signal influence concentrated on a range. The developed decoding
algorithms for signal constructions with noise signals concentrated on a range
involve Fast Fourier Transformation (FFT) with preceding weight window, clipping
and interleaving of spectral component values and evaluation of soft output
decisions from demodulator for reception. There are recommendations for choice
of optimal weight windows that effective for mitigation of the investigated
noise signals in the article. The class of optimal weight windows includes
Hamming window and Kaiser window with parameter β=6...9.
The analysis of
noise-immunity in presence to 5 noise signals concentrated on a range with
signal/noise -40 dB and AWGN (additive white Gaussian noise) is implemented for
signal construction by means of computer simulations of developed processing
algorithms. The results of computer simulations show the differences between
the resulted error-performances and for the ideal error-performances under
assumption existing only AWGN not more 0.5 dB for bit-error 10-5.
Key words: OFDM, noise reduction,
narrow-band noise, Kaiser window, Hamming window.
References
1. Liu H., Li
G. OFDM-Based Broadband Wireless Networks. Hoboken: John Wiley & Sons.
2005. 251 p.
2. Bakulin
M.G., Kreindelin V.B., Shloma A.M., Shumov A.P. Technologia OFDM. [OFDM
Technology]. Moscow, Telecom Publ., 2016. 352 p. (In Russian)
3. Akhmed N., Rao K.R. Ortogonalnye
preobrazovaniya pri tsifrovoy obrabotke signalov. [Orthogonal
transformations in digital signal processing]. Moscow, Svyaz Publ. 1980. 248 p.
(In Russian).
4. Shinakov
Y.S. Power spectral density of interference caused by
nonlinear distortions in devices with amplitude-phase conversion. Journal
of Communications Technology and Electronics, 2013, Vol. 58, No.10, pp.
1024-1034. DOI:
10.1134/S106422691310001X
5. Shinakov Y.S. Two methods of
output signal power calculation for devices with amplitude-phase conversion.
Radiotechnika - Radioengineering, 2016, No. 2, pp. 66-71. (In
Russian)
6. Nazarov
L.E., Zudilin A.S. Estimating the power and efficiency of
intermodulation interferences under the OFDM-signal-envelope limitation.
Journal of Communications Technology and Electronics, 2015, Vol. 60,
No.5, pp. 489-495. DOI:
10.1134/S1064226915050071
7.
Nazarov L.E., Zudilin A.S. Techniques for estimating the
power of the intermodulation interferences of orthogonal frequency-division
multiplexing signals. Journal of Communications Technology and
Electronics, 2014, Vol. 59, No.2, pp. 158-163. DOI:
10.1134/S1064226914020041
8. Nazarov
L.E., Zudilin A.S. Techniques for narrow band noise reduction for OFDM signals. Izvestija
vysshih uchebnyh zavedenij.Elektronika - Russian microelectronics, 2013, No. 6
(104), p. 45-51. (In Russian)
9.
Kalinin V.I., Radchenko D.E., Cherepenin V.A. The error-performances of digital
channels based on continue noise signals under spectral modulation. Radiotechnika-Radioengineering,
2015, No. 8, pp. 84-94. (In Russian)
10. Fink L.M. Teoriya peredachi discretnykh soobschenii. [The
theory of discrete message transmission]. Moscow, Sov. Radio Publ. 1970. (In
Russian).
11. Widrow B., Stearns S.D. Adaptive signal processing. Prentice-Hall,
Inc. Englewood Cliffs, N.J. 07632. 1985.
12. Zudilin
A.S., Nazarov L.E. Analysis of noise immunity for signal constructions based on
ofdm and error-correcting codes robusted for signal influence concentrated on a
range. Zhurnal Radioelektroniki - Journal of Radio Electronics. 2017. No.11.
http://jre.cplire.ru/jre/nov17/4/text.pdf
(In Russian)
13. Nazarov
L.E., Sheglov M.A. The Characteristics of Full and Shortened Immune-Noise LDPC
Codes Based on Finite-Geometry. Uspekhi sovremennoy radioelektroniki - Achievements of Modern Radio Electronics.
2017. No. 6. pp.23-30. (In Russian)
14. TM synchronization and
channel coding - summary of concept and rationale. Information report CCSDS
130.1-G-1. Green Book. 2006.