In this thesis, the feasibility of complete complementary code based OFDM CDMA system is studied. The complete complementary code is composed of several sets of auto-complementary codes, any two of which are cross-complementary codes. The perfect correlation between code sets is the distinguishing feature of complete complementary code. In this thesis, we designed a new OFDM CDMA system architecture according the property of complete complementary code. The most obvious characteristic is that the bit stream in the new system is no longer aligned one bit after another in time. Instead, a new bit will start only after one chip delay relative to the previous bit, which is spread by an element code of complete complementary code. The proposed new CDMA architecture can offer an MAI-free operation in both down-link (synchronous channel) and up-link (asynchronous channel) transmission under the AWGN channel, because of the use of the CC-codes. However, due to the special spreading modulator-offset stacking modulator (OSM), we¡¦ll encounter a ¡§ multi-level ¡¨ problem . If we can¡¦t solve this problem , the linear power amplifier will not be able to support the whole system . Hence , we try to clip the multilevel into a smaller magnitude . And also , we try some other mapping methods to solve the multilevel problem .

Differential space time block coding is a technology that combining traditional space time block coding and differential coding. Differential space time block coding could exploit full spatial diversity gain where the channel state information is not known. Each user in CC-CDMA system is assigned a fold of codes which sent via different carriers to reconstruct perfect auto-correlation and cross-correlation function. Complete Complementary codes could offer MAI-free and MI-free operation for DS-spreading. In this thesis we combine differential space time block coding and CC-CDMA, and discuss the character of the system.