ABSTRACT
Orthogonal frequency division multiplexing (OFDM) transmission technique plays an important role in this area. OFDM is a very convenient transmission technique present in the most successful air interface standards of WiFi and WiMAX. Multiple input multiple output (MIMO) systems have an increasing importance to guarantee high data rate transmission schemes. MIMO techniques are well-known techniques to increase the data rate maintaining a given signal to noise ratio (SNR) and bit error rate (BER). The combination of the OFDM transmission technique and multiple antenna MIMO systems is the key focus of this chapter. Robustness and bandwidth efficiency (BE) of new differential transmission techniques, improved by the use of diversities, in particular spatial diversity and the related advantages, are discussed. Differential modulation schemes have the advantage that any radio channel estimation procedure can be avoided which reduces the computation complexity dramatically. In this chapter a differential MIMO-OFDM technique called differential space time block code (DSTBC) is described.
