Design and Performance Evaluation of the MIMO SFBC CI-OFDM Communication System

The CI-OFDM (carrier interferometry orthogonal frequency division multiplexing) CI-OFDM system spreads each information symbol across all N sub-carriers using orthogonal CI spreading codes. The CI-OFDM system can show the advantage of PAPR (peak to average power ratio) reduction and frequency diversity gains without any loss in the communication throughput. In this paper, focusing on the two Tx (transmit) / one Rx (receive) antennas and two Tx / two Rx antennas configuration in the MIMO (multiple input multiple output) antenna array systems, we like to design and evaluate the performance of this MIMO CI-OFDM system. SFBC (space frequency block coding) coding is used for the MIMO CI-OFDM system. For CI-OFDM realization, digital implemented CI-OFDM structure is used in which CI code spreading operation and carrier allocation are separately processed by simple IFFT type operation. From the simulation results, it is shown that MIMO SFBC CI-OFDM reduces PAPR significantly compared with the conventional MIMO SFBC-OFDM system. The out-of band re-growth of signal spectrum in MIMO SFBC CI-OFDM system is much smaller than MIMO SFBC OFDM. In the NBI (narrow band interference) channel MIMO SFBC CI-OFDM system achieves considerable BER improvement.