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Reducing the PAPR of OFDM Systems by Random Variable Transformation
Montadar Abas Taher,Mandeep Jit Singh,Mahamod Bin Ismail,Salina Abdul Samad,Mohammad Tariqul Islam 한국전자통신연구원 2013 ETRI Journal Vol.35 No.4
Peak power reduction techniques in orthogonal frequency division multiplexing (OFDM) has been an important subject for many researchers for over 20 years. In this letter, we propose a side-information-free technique that is based on the concept of random variable (RV) transformation. The suggested method transforms RVs into other RVs, aiming to reshape the constellation that will consequently produce OFDM symbols with a reduced peak-to-average power ratio. The proposed method has no limitation on the mapping type or the mapping order and has no significant effect on the bit error rate performance compared to other methods presented in the literature. Additionally, the computational complexity does not increase.
Yasir Amer Jawhar,Khairun Nidzam Ramli,Montadar Abas Taher,Nor Shahida Mohd Shah,Lukman Audah,Mustafa Sami Ahmed,Thamer Abbas 한국전자통신연구원 2018 ETRI Journal Vol.40 No.6
Orthogonal frequency division multiplexing (OFDM) has been the overwhelmingly prevalent choice for high‐data‐rate systems due to its superior advantages compared with other modulation techniques. In contrast, a high peak‐to‐average‐power ratio (PAPR) is considered the fundamental obstacle in OFDM systems since it drives the system to suffer from in‐band distortion and out‐of‐band radiation. The partial transmit sequence (PTS) technique is viewed as one of several strategies that have been suggested to diminish the high PAPR trend. The PTS relies upon dividing an input data sequence into a number of subblocks. Hence, three common types of the subblock segmentation methods have been adopted—interleaving (IL‐PTS), adjacent (Ad‐PTS), and pseudorandom (PR‐PTS). In this study, a new type of subblock division scheme is proposed to improve the PAPR reduction capacity with a low computational complexity. The results indicate that the proposed scheme can enhance the PAPR reduction performance better than the IL‐PTS and Ad‐PTS schemes. Additionally, the computational complexity of the proposed scheme is lower than that of the PR‐PTS and Ad‐PTS schemes.
Improving PAPR performance of filtered OFDM for 5G communications using PTS
Al-Jawhar, Yasir Amer,Ramli, Khairun N.,Taher, Montadar Abas,Shah, Nor Shahida M.,Mostafa, Salama A.,Khalaf, Bashar Ahmed Electronics and Telecommunications Research Instit 2021 ETRI Journal Vol.43 No.2
The filtered orthogonal frequency division multiplexing (F-OFDM) system has been recommended as a waveform candidate for fifth-generation (5G) communications. The suppression of out-of-band emission (OOBE) and asynchronous transmission are the distinctive features of the filtering-based waveform frameworks. Meanwhile, the high peak-to-average power ratio (PAPR) is still a challenge for the new waveform candidates. Partial transmit sequence (PTS) is an effective technique for mitigating the trend of high PAPR in multicarrier systems. In this study, the PTS technique is employed to reduce the high PAPR value of an F-OFDM system. Then, this system is compared with the OFDM system. In addition, the other related parameters such as frequency localization, bit error rate (BER), and computational complexity are evaluated and analyzed for both systems with and without PTS. The simulation results indicate that the F-OFDM based on PTS achieves higher levels of PAPR, BER, and OOBE performances compared with OFDM. Moreover, the BER performance of F-OFDM is uninfluenced by the use of the PTS technique.