Concatenative Complete Complementary Code Division Multiple Access and Its Fast Transform

Abstract

Over multipath channels, complete complementary code division multiple access (CC-CDMA) and convolutional spreading code division multiple access (CS-CDMA) provide inter-channel interference (ICI) free transmission with an enhanced spectral efficiency (SE). However, the convolutional spreading (CS) operation of the systems is computationally complex and involves a high peak-to-average power ratio (PAPR). To address such issues, we propose the concatenative complete complementary code (CCCC) division multiple access, named (CCC-CDMA). Since the CCCCs can be generated from the rows of the Walsh-Hadamard or discrete Fourier transform (DFT) matrices, the CS operation can be implemented using corresponding fast transforms (FTs) to reduce computational complexity. Simulation results show that the enlargement of the spreading factor (SF) strengthens the robustness against clipping noise. The binary CCCC generated by Walsh-Hadamard matrix exhibited excellent robustness against Doppler frequency shifts. Index Terms CDMA, complete complementary codes, zero correlation zone sequences, CC-CDMA, CS-CDMA I. INTRODUCTION To date, the generational changes of mobile communication technology have been primarily characterized by the adopted multiple access (MA) schemes. In the first generation, users have H. Mizuyoshi and C. Han was with the