Performance of hybrid carrier DS CDMA communication system

This paper proposes a hybrid carrier DS CDMA communication system, combining 4-weighted fractional Fourier transform (4-WFRFT) with code division multiple access (CDMA). The signals are modulated in an order fractional domain and transformed by 4-WFRFT. In the time domain CDMA technique is adopted for multiple accesses and time diversity gain. The bit energy in 4-WFRFT system is distributed on the time-frequency plane more evenly and symmetrically, compared to orthogonal frequency division multiplexing (OFDM) system, in which Fourier transform is used. When there is a deep fading notch or single-frequency interference in the channel, the proposed method can split the interference to a broader range in order to reduce the influence, resulting in the better system performance.