A Multi-Levelled OFDM-CDMA Modem Using Complete Complementary Codes
In this paper, the authors introduce a novel multiple access scheme based on a combination of a multi-levelled modem and multi-carrier techniques with the use of complete complementary codes. This modulation technique combines a multi-dimensional Code Division Multiple Access (CDMA) modem with recent designs of perfectly complete complementary orthogonal codes. The rotational properties of the spreading codes are further exploited to improve the modulation technique, throughput, spectral efficiency, and capacity. Additionally, the system is extended by making use of multiple carrier frequencies as in OFDM, with the additional benefits of being able to spread data in frequency and/or in time.