New catenated OFDM modulation scheme in zero cross correlation OCDMA at various number of user and effective powerN. M. Nawawi, M. S. Anuar, M. N Junita and Mohd Rashidi Che BesonMATEC Web Conf., 140 (2017) 01015DOI: https://doi.org/10.1051/matecconf/201714001015