Linear dispersion codes (LDC) can support arbitrary configurations of transmit and receive antennas in multiinput multi-output (MIMO) systems. In this paper, we investigate two transmit diversity applications of LDC for orthogonal frequency division multiplexing (OFDM) systems in order to achieve space-time/frequency (ST/SF) diversity gains when transmitting over time-/frequency-selective fading channels. LDC-aided ST/SF-OFDM is flexible in configuring various numbers of transmit antennas and time-slots or frequency-tones. Our results show that the ST-OFDM scheme is sensitive to exploiting diversity gains, subject to the impact of varying channel Doppler spreads; while the performance of SF-OFDM is mainly subject to delay spread. Particularly, when the transmitter employs more than two antennas, the LDC-aided ST/SF-OFDM outperforms the orthogonal block codes (e.g. Tarokh's codes) aided ST/SF-OFDM, when communicating over higher Doppler/delay spread.
IEEE Wireless Communications and Networking Conference (WCNC)
April 3-6, 2016
MIMO, OFDM, LDC, 5G, wireless networks