The raised cosine is a bandwidth efficient pulse shaping waveform with relatively high peak to average power ratio (PAPR) for smaller excess bandwidths. Reducing the PAPR while maintaining the shaped waveform integrity and bandwidth efficiency increases the transmission rate by utilizing the spectrum more effectively. In this paper, we modify the raised cosine by reducing the adjacent symbol contribution to the PAPR with small increase in the Error Vector Magnitude (EVM) and the required bandwidth over the raised cosine waveform. The attained PAPR reduction is on the order of 1.5 dB for the smaller excess bandwidth.
The raised cosine waveform is a common efficient waveform to control the bandwidth reduction of a communications signal at the cost of controlled Inter Symbol Interference (ISI) with relatively large Peak to Average Power Ratio (PAPR). Reducing the PAPR has been addressed extensively in the literature using methods such as the clipping and coding the data among others. In this paper, we reduce the PAPR by windowing the raised cosine waveform to minimize contributions to PAPR with minimal spectral growth. We simulate the modified raised cosine to determine the reduction in PAPR for various Quadrature Amplitude Modulation (QAM) orders and excess bandwidths.