Saurav Kumar, et. al. International Journal of Engineering Research and Applications www.ijera.com ISSN: 2248-9622, Vol. 12, Issue 4, (Series-III) April 2022, pp. 36-41 www.ijera.com DOI: 10.9790/9622-1204033641 36 | Page MIMO-OFDM System PAPR and BER Reduction Using MPTS and DWT-DCT Technique Saurav Kumar 1 , Prof. Amrita Khera 2 1 Research Scholar, Trinity Institute of Technology & Research, Bhopal, India 2 Faculty Electronics’ & Communication Dept., Trinity Institute of Technology & Research, Bhopal, India ABSTRACT Multiple Input Multiple Output (MIMO) in combination with Orthogonal Frequency Division Multiplexing (OFDM) is of great interest for researchers and research laboratories all over the world. OFDM is widely used in contemporary communication systems for its good robustness in multipath environment, and its high spectral efficiency. The capacity of wireless system can be increased dramatically by employing Multiple Input Multiple Output, (MIMO) antennas. The combination of MIMO and OFDM system is found to be very beneficial. A major drawback of OFDM-MIMO System is its high Peak to Average Power Ratio (PAPR) Reduction. The peak power of a signal is a critical design factor for band limited communication systems, and it is necessary to reduce it as much as possible. Many PAPR reduction techniques have been used to reduce PAPR. Partial transmit sequence (PTS) is one of the most well-known peak-to-average power ratio (PAPR) reduction techniques proposed for MIMO-OFDM systems. However the computational complexity of traditional PTS method is tremendous. In this paper a new partial transmit sequence (PTS) technique, based on PTS with discrete wavelet transform (DWT) and discrete cosine transform (DCT) technique, for two antennas MIMO- OFDM system, is proposed which can achieve better PAPR performance at much less bit error rate (BER). Simulation results show that the proposed approach can reduce BER and achieve a better PAPR reduction compared to previous PTS technique. Keywords— PTS, DWT, DCT, MIMO-OFDM, PAPR, BER --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 09-04-2022 Date of Acceptance: 26-04-2022 --------------------------------------------------------------------------------------------------------------------------------------- I. INTRODUCTION A combination of multiple input multiple output (MIMO) and orthogonal frequency division multiplexing (OFDM) (MIMO-OFDM) is an emerging technology for high speed data multi- carriers transmission in future wireless communication network systems such as digital audio broadcasting (DAB), digital video broadcasting (DVB), medical body area networks (MBANs) applications, the fourth and the fifth generation (4G,5G) of mobile network. In MIMO- OFDM system, the output is the superposition of multiple sub-carriers. Whenever, the phases and frequencies of these carriers match coherently, instantaneous power outputs may increase greatly and become higher than the mean power of the high power amplifier (HPA) resulting in large PAPR [1]. Lot of research work has been done for solving the problem of PAPR that concerns all kind of multicarrier signals. So, many techniques have been proposed such as clipping [2], tone reservation [3], nonlinear transformations [4], coding [5], selecting mapping (SLM) [6] and partial transmit sequence (PTS). Modified approaches of PTS are proposed in that produce better results; however, the computational complexity is still remaining unsolved totally. In this paper an approach is proposed to reduce the PAPR in STBC MIMO- OFDM systems with less computational complexity. So, the mean idea is based on PTS with discrete wavelet transform (DWT) and discrete cosine transform (DCT). The rest of the paper is organized as follows: in section II, MIMOOFDM system is explained. Section III describes the PTS algorithm. Section IV shows the proposed algorithm, simulation results and the paper are concluded in section V and section VI. II. MIMO-OFDM SYSTEM MIMO in combination with OFDM is widely used nowadays due its best performance in terms of capacity of channels, high data rate and good outcome in frequency selective fading channels [7]. In addition to this it also improves reliability of link. This is attained as the OFDM can transform frequency selective MIMO channel to frequency flat MIMO channels [8]. So it is widely used in future broadband RESEARCH ARTICLE OPEN ACCESS