MIMO TDCS with Extra Embedded Symbol for Higher Data Rates in Overlay Spectrum Sharing System

In this paper an extension to our work on embedded symbol in TDCS-CCSK system [1] is provided by adding MIMO and V-BLAST receiver architecture to the system in order to counteract the fading of the wireless channel. The embedded symbol can be derived from PAM, QAM or PSK mapping. In the context of overlay spectrum sharing PSK is considered as the most appropriate mapping for the embedded symbol since it has no impact on the overall TDCS-CCSK power spectrum density. As each transmit antenna transmits different data, the bit rate of the proposed TDCS system becomes higher. The simulation results show that for the ratio between the number of the transmit antennas and the receive antennas of 1/2 or lower, the bit error rate (BER) performance improves significantly. The limit of the embedded symbol constellation size to have a better overall BER compared to the conventional TDCS-CCSK in MIMO VBLAST system is found to be 16.