The high peak-to-average power ratio (PAPR) of the existing orthogonal frequency division multiplexing (OFDM) based systems, is a major issue which needs attention because it significantly lowers energy efficiency. Furthermore, in the single carrier frequency division multiple access (SC-FDMA), side lobe suppression of an impulse response significantly impacts PAPR reduction. To lower PAPR in the SC-FDMA, we suggested two novel families of Nyquist-I pulses: improved parametric exponential pulse (iPEP) and improved parametric linear pulse (iPLP). The iPEP and iPLP are distinguished by their innovative design parameters and exponential expressions, which permit reasonable fluctuations in the impulse response's side lobe amplitude to reduce PAPR for a given roll-off factor. Theoretical and numerical simulations were employed to determine sub-optimal values for the new design parameters. The results showed that the proposed pulses for the SC-FDMA (interleaved subcarrier mode) reduce PAPR and symbol-error-rate (SER) for single-input-single-output (SISO) systems and decrease PAPR for (2x2) multiple-input-multiple-output (MIMO) systems, sufficiently when compared to other existing filters.