Abstract:
Broadband orthogonal frequency code division multiple access (OFCDMA) with two dimensional
spreading is a promising candidate for Beyond fourth Generation (B4G) networks. Since wideband
channels are highly frequency-selective, orthogonality among orthogonal spreading codes are no longer
maintained. Therefore, multiple code interference (MCI) is inevitable in OFCDMA-based systems.
Multiple-Input Multiple-Output (MIMO) will be a key technology of future wireless communication
systems. In MIMO-OFCDMA systems, in addition to MCI, inter-spatial stream interference (ISSI) will
also exist. Even though maximum a posteriori probability (MAP)-based detectors provide the best
performance, their computational complexity is high. Alternatively, minimum mean-square error
(MMSE) detectors can be used to obtain a better tradeoff between the complexity and the performance.
;
Several interference cancellation techniques were proposed under LTE Advanced, B4G standardizations
and corresponding literature. One such technique is zero-forcing MAI nulling and cancellation based on
QR decomposition (ZF-QRD). That can be used to cancel the MAI separately. But we are proposing a
combined ISSI and MCI cancellation technique. We also compare the performance of MIMO VSFOFCDMA recursive ISSI and MCI cancellation scheme with conventional MC-CDMA, MC-DS-CDMA,
MT-CDMA and OFCDMA.
