PAPR reduction for downlink LTE system based on DCT and Hyperbolic Tangent Companding noise cancellation

Abstract

A joint Hyperbolic Tangent Companding (HTC) technique and Discrete Cosine Transform (DCT) has been proposed to decrease of the PAPR ratio effects of the OFDMA System. The proposed schema utilizes DCT instead of the traditional discrete Fourier transform (DFT) as a requisite function to perform DCT OFDMA. HTC is an actual process to minimize the high PAPR of DCT OFDMA. However, the companded DCT OFDMA suffers from the bit-error-rate (BER) performance degradation by companding noise introduced. So, an effective scheme of estimation and noise cancellation for the compressed DCT OFDMA is introduced. By expressing the compressed signals as a combination of the main signals adding with the component of compressed noise, and the estimated compressed noise deduct from the received signals, leading to enhance the BER performance of the proposed system. The new proposed scheme minimizes PAPR by about 6.3 dB and 7.3 dB compare respectively, with the DFT OFDMA and DCT OFDMA without commanding. Also, it is noted that the proposed scheme of estimation and companding noise cancellation for the companded DCT OFDMA provides a great lowest BER degradation that can be neglected comparing with the premier DCT SC-FDMA system without PAPR reduction.