On the error probability of quasi-orthogonal space-time block codes

In this paper, we derive the exact pairwise error probabilities (PEPs) of various quasi-orthogonal space-time block codes (QO-STBCs) using the moment generating function. By classifying the exact PEPs of QO-STBCs into three types, we derive the closed-form expression for each type of PEP. Based on these closed-form expressions, we obtain the union bounds on the symbol error probability and bit error probability for QPSK modulation. Through simulation, it is shown that these union bounds are quite tight.