PAPR Reduction an effective approach for next frontier MIMO-OFDM systems

The ‘Orthogonal frequency division multiplexing (OFDM)’ is a well-accepted and effective technology employed today and in future wireless communication systems. The combinations of OFDM and ‘multiple-input multiple-output (MIMO’) offer high quality of services and better throughput. The multicarrier OFDM system experiences a high ‘peak-to-average power ratio (PAPR’), which is the major issue in the OFDM scheme and must be truncated to achieve trustworthy communication. Due to high PAPR in a signal to be transmitted, the power amplifier in the transmitter section enters into saturation region and amplifies the signal nonlinearly, resulting in loss of orthogonality and ultimately in ‘inter-carrier interference (ICI)’. In this article, the 'iterative clipping and filtering (ICF)' method is proposed to minimize the PAPR in the OFDM system. The simulation is carried out using MATLAB (version 2014b). The result of the proposed ICF method and the ‘selective mapping (SLM)’ scheme is analyzed and compared. From the analysis, it is shown that the proposed ICF technique is more suitable for minimizing the PAPR effectively without affecting ‘bit error rates (BER)’ much and the simplicity of the system. The simulation result of the proposed ICF scheme using ‘Quadrature Phase Shift Keying (QPSK)’, FFT size of 128, and clipping and filtering level up to 6 shows that the proposed ICF scheme for clipping level of 6 reduces PAPR to 5dB. Also, the BER is minimized at the level of 3×10−5 at 12 dB SNR.

Peak to Average Power Ratio Reduction Techniques

Multiple-input to multiple-output (MIMO) and orthogonal frequency division multiplexing (OFDM) are the utmost widely used wireless communication system because of its large benefits and advantageous. Though MIMO OFDM systems have high advantages there is a major drawback that makes the system noisy and the inefficient use of bandwidth. This drawback mainly occurred due to the spikes in the transmitting signal. These spikes make the value of peak to average power ratio of the signal high and results in distortion and noise in the signal. To avoid these spikes there are number of techniques introduced. We will discuss about the three methods namely partial transmit sequence, clipping and filtering method, Selective Mapping technique. All these methods are used to decrease the high peak to the average ratio by removing the spikes in the signal. And we will see the outputs obtained by using MATLAB software. Clipping and filtering technique would be the simplest technique to lower the peak to average power ratio while partial transmit technique is the most efficient method to diminish the peak to the average power ratio.

Evaluasi Penerapan Algoritma Neural Network Sebagai Teknik Reduksi PAPR Pada Sistem OFDM

Pada makalah ini dilakukan evaluasi kinerja algoritma Neural Network sebagai teknik reduksi sistem OFDM. Hasil simulasi untuk sinyal OFDM dengan jumlah subcarrier sebanyak 64 dan modulasi 16 QAM menunjukkan penerapan algorima NN menghasilkan penurunan nilai PAPR sekitar 5,6 dB dari PAPR sinyal OFDM tanpa reduksi. Juga dibandingkan dengan teknik reduksi PAPR metode Iterative Clipping and Filtering, (ICF), Selective Mapping (SLM) dan Partial Transmit Sequence (PTS). Dari kurva CCDF juga ditunjukkan bahwa metode NN menghasilkan kinerja yang lebih baik dibanding metode digabungkan dengan teknik Iterative Clipping and Filtering, (ICF), Selective Mapping (SLM) dan Partial Transmit Sequence (PTS). Evaluasi di sisi penerima dengan pengamatan nilai bit error rate, penerapan algoritma NN memiliki kinerja yang terbaik