Abstract:
By taking advantage of frequency-based multiplexing, OFDM (Orthogonal Frequency Division Multiplexing) has since proven itself as an effective means of achieving high data rates, high spectrum effciency and immunity to ISI (Inter-Symbol Interference). Recent interests have shifted towards creating an additional degree of orthorgonality by combining spatial multiplexing available in Multiple-Input Multiple-Output (MIMO) communication systems (which use multiple transmitter and receiver antennas) with frequency-based multiplexing in OFDM. This system, henceforth referred to as MIMO- OFDM, allows spatial-multiplexing to be used over frequency selective channels with- out complex equalizers. The first part of this project introduces the MIMO channel model which is defined by the channel's H matrix, spatial correlation matrix and the MIMO channel capacity. The next part provides a brief study of the OFDM scheme, showing its implementation, time and spectral characteristics, and its immunity to ISI and frequency selective chan- nels. The last part will investigate the MIMO-OFDM scheme and is advantage over conventional MIMO systems, covering aspects such as space-time multiplexing and channel estimation. Some in-depth analysis will be carried out backed by simulation data which will help validate and explain the various models and results presented in current literature.
