AIRCC PUBLISHING CORPORATION
A NEW APPROACH TO IMPROVE THE PERFORMANCE OF OFDM SIGNAL FOR 6G COMMUNICATION
Usha S.M1 and Mahesh H.B2
1Department of Electronics & Communication Engineering, JSS Academy of Technical
Education, Bengaluru, Visveswaraya Technological University, India
2Department of Computer Science Engineering, PES University, Bangalore, India
The orthogonal frequency division multiplexing is a very efficient modulation technique that can achieve very high throughput by transmitting many carriers simultaneously and it is spectrally efficient because of the proximity of the subcarriers. OFDM is used in 5G communication for higher data transmission. 6th generation communication also demands OFDM, since it is more spectrally efficient and suitable for high data transmission. The drawback of the OFDM includes peak to average power ratio and sensitivity to carrier offsets and drifts. The usage of a non-linear power amplifier causes the signal spreading and leads to inter-modulation and signal constellation distortion. These two distortions have an impact on the signalto-noise ratio and hence reduce the efficiency. The methods used to reduce PAPR are clipping and filtering, selective mapping, partial transmit sequence, tone reservation, and injection and non-linear commanding. The drawbacks of the above methods are computational complexity, spectrum inefficiency, increase in bit error rate and PAPR rate. In this work, three effective methods are discussed and compared to improve the performance parameters. These are adaptive peak window method based on harmonize clipping, harmonics kernel adaptive filter and Slepian-based flat-top window techniques are presented to reduce the BER, PAPR, and CCDF to improve the signal-to-noise of the system. This window technique averages out the noise spread out in the spectrum and thus reduces the signal loss by minimizing peak to average power ratio. The results are analyzed and compared with the existing conventional methods. Finally, the reductions in PAPR, BER and CCDF obtained are discussed in the results and comparison section. The proposed work has a higher signal-to-noise ratio than the conventional methods.
Orthogonal Frequency Division Multiplexing, Peak to Average Power Ratio, Selective Mapping, Filtering and clipping, PTS, Bit Error rate, 6G.
Bandwidth can be efficiently utilized by transmitting the signals orthogonally. The signals transmitted from the earth stations have to propagate for longer distances to reach the satellite in space. When the signal is propagating, it is affected by many environmental parameters. The signal collides with the taller buildings, hill stations, long towers, etc. It decreases signal strength due to fading and inter-symbol interference. The fading can be minimized by sending signals orthogonally but this increases the peak to average power ratio [1-3]. PAPR increases the interference level and decreases the system performance [4-5]. Orthogonal multiplexing is a multi-carrier modulation technique. It is more spectrally efficient, robustness against multi-path signal fading and supports large data transmission. As a result, OFDM is widely used in many radio communication applications. OFDM transmits the data simultaneously by splitting large data streams into smaller data streams via many subcarriers [6-7]. OFDM also minimizes the dispersion that occurs due to the signal spreading. The reason for signal spreading is the intersymbol interference and cross talk. The signal spreading due-to time delay is minimized by sending signals orthogonally [8-9].
The implementation of OFDM is shown in Figure 1. At the transmitter, the samples X0, X1, X2, X3…….XN-1 applied to IDFT block, the IDFT converted signal is passed through a channel. At the receiver, DFT is performed on incoming IDFT data samples. The composite OFDM data block is defined by Eq. (1).
Figure 1. OFDM Implementation
Table 1. Parameter description
Dr. Usha S.M. from Bengaluru- Karnataka, India, obtained B.E (Electronics & Communication Engineering) degree from Mysore University in the year 2000. M.Tech. in VLSI Design and Embedded Systems from VTU Belgaum in 2011 and awarded Ph.D. in Optimization and Performance Analysis of Digital Modulators from VTU Belgaum in the year 2017. She is currently working as Associate Professor at JSS Academy of Technical Education, Bengaluru. Karnataka, India. She is a member of Professional bodies such as IEEE, ISTE, and MIE. The research area of interest is VLSI design and wireless communication.