• Akshay S. Chaware
• Poonam T. Agarkar
• Dr. Narendra P. Giradkar
• Dr. Sanjay L. Badjate

Orthogonal Frequency Division Multiplexing (OFDM) is one of the most promising multi-carrier system which forms basis for all 4G wireless communication systems due to its large capacity to allow the number of subcarriers, high data rate and ubiquitous coverage with high mobility. OFDM is significantly affected by Peak to Average Power Ratio (PAPR). Unfortunately, the high PAPR inherent to OFDM signal envelopes will occasionally drive high power amplifiers (HPAs) to operate in the nonlinear region of their characteristic curve. The nonlinearity of the HPA exhibits amplitude and phase distortions, which cause loss of orthogonality among the subcarriers, and hence, inter-carrier interference (ICI) is introduced in the transmitted signal. The high PAPR also leads to in-band distortion and out of-band radiation. To increase the performance of OFDM signals, the partial transmit sequence (PTS) shows a significant reduction and improvement in PAPR. As one of attractive techniques, PTS scheme provides an effective solution for PAPR reduction of or OFDM signals. Theoretical analysis and simulation in literature using single input single output (SISO) with PTS results showed that, PTS can not only dramatically reduce computational complexity but also have an advantage of no loss in PAPR reduction performance. This proposed work emphasis mainly on the PAPR reduction in Multi input multi output (MIMO) -OFDM system using PTS technique with Least square (LS) and Least minimum mean squared error (LMMSE) channel estimations techniques. The results obtained showed that PTS gives low Bit error rate (BER) as compared to system without PTS with both channel estimation techniques for a range of values for signal to noise ratio (SNR).

Orthogonal frequency division multiplexing, Peak to Average Power Ratio, High power amplifiers, Inter-carrier interference, Partial Transmit Sequence, Single Input Single Output, Multiple Input Multiple Output, Least Square, Linear-minimum-mean-square-error , Signal to Noise Ratio , Bit Error Rate.

"Performance of LS/LMMSE based channel estimated MIMO-OFDM System using Grouped Phase Transmit Sequence", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 4, page no.43-48, April-2019, Available :http://www.jetir.org/papers/JETIR1904M09.pdf

"Performance of LS/LMMSE based channel estimated MIMO-OFDM System using Grouped Phase Transmit Sequence", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 4, page no. pp43-48, April-2019, Available at : http://www.jetir.org/papers/JETIR1904M09.pdf