A Novel Multi-carrier Order Division Multi-access Communication System Based on TDCS with Fractional Fourier Transform Scheme

• Published in: Wireless personal communications Vol. 79; no. 2; pp. 1301 - 1320
• Main Authors: Yang, Zeyi, Tao, Ran, Wang, Yue, Wang, Teng
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.11.2014; Springer
• Subjects: Applied sciences; Carriers; Chirp; Coding, codes; Communication systems; Communications Engineering; Computer Communication Networks; Computer science; control theory; systems; Computer systems and distributed systems. User interface; Demodulation; Division; Engineering; Exact sciences and technology; Fourier transforms; Information, signal and communications theory; Interference; Modulation; Networks; Signal and communications theory; Signal,Image and Speech Processing; Software; Telecommunications and information theory; Multiple access; Multiple chirp carriers inter-shielding; Transform domain communication system; OFDM; Fractional Fourier transform; Capability index; Streaming; Fourier transformation; Leak; Multicarrier; Frequency division multiple access; Shielding; Variable bit rate; Fractional derivative; Multicarrier modulation; Mathematical transformation; Wide band; Code division multiple access; Orthogonal frequency division multiplexing; Collision avoidance; Demodulation
• ISSN: 0929-6212; 1572-834X
• DOI: 10.1007/s11277-014-1931-8

In this paper, we propose a novel fractional Fourier transform (FrFT) based multi-carrier order division multi-access communication system, in which each user is uniquely identified by an FrFT order. Transform domain communication system (TDCS) with FrFT scheme is also proposed to synthesize the wide-band baseband waveforms in all FrFT domains with different users’ FrFT orders, which enhances the interference avoidance capability of this system under most of interference. Therefore, multiple independent data streams can be transmitted by using FrFT–OFDM in the same time and different FrFT domains. However, chirp bases, as the new kind of carriers with different modulated rates, are merely mutually approximately orthogonal. There is a problem of energy leakage between multiple chirp carriers, which possibly causes the multiple chirp carriers inter-shielding to influence the FrFT–OFDM demodulation performance. An efficient allocation algorithm of multiple chirp carriers by presetting the carrier parameters is proposed to solve this problem. Based on MC-CDMA, a variable bit rate system structure is proposed for TDCS with FrFT scheme under different channel environments. In order to simplify the process of modulation and demodulation of TDCS with FrFT scheme, a whole new cyclic shift key modulation mode in FrFT domain is also proposed. Both theories and simulations confirm strictly the validity of the proposed system.