Carrier aggregation (CA) is one the techniques to increase the system bandwidth but with carrier aggregation it increases the peak-to-average power ratio (PAPR) level to worsen the system performance. In this paper we consider to include a spectral filter with roll-off square-root raised cosine structure or to include the same spectral filter cascading with phase randomization in every component carrier (CC) path to improve the PAPR level. One to five CCs are considered in the aggregated transmission system the resulting complementary cumulative distribution function (CCDF) PAPR levels for each possible aggregated system are simulated and compared when QPSK, 16-QAM, 64-QAM, and 256-QAM modulation formats are considered when the roll-off factor of the square-root raised cosine filter varies from 0 to 1. The simulation results are tabulated that can be used as the design reference in the selection of the best roll-off factor in the spectral filter to have the best PAPR performance.
