Spatial Diversity and Channel Coding Gain in a noncoherent MIMO-OFDM transmission system

The Orthogonal Frequency Division Multiplexing (OFDM) transmission technique, in combination with multiple transmit and/or receive antenna systems (MIMO) is a powerful technical combination for all future wireless system design. Due to multipath propagation inside the radio channel and the resulting frequency selectivity the bit error rate (BER) performance is very low in all uncoded OFDM based systems. therefore, channel coding is important and necessary in all OFDM systems to ensure a robust and reliable data transmission. Differential Space-Time Block Codes (DSTBG) are designed for a noncoherent transmission system which is equipped by multiple transmit antenna elements. DSTBC has the strong advantage that no channel state information is required at all and exploit the spatial diversity to improve the link reliability. If a coded MIMO OFDM system is considered the question arises how channel coding is influenced by the spatial diversity and vice versa. Therefore, in this paper a quantitative evaluation of a MIMO-OFDM system is considered and the related BER curves versus the Signal to Norse Ratio (SNR) will be calculated.