TABLE OF CONTENTS In this section, we provide simulation results for the performance of the OSTBCs given in the previous sections. Figure 4.4 illustrates a block diagram of the STBC encoder. The information source is divided into blocks of Kb bits. Using these Kb bits, the encoder picks K symbols from the constellation. The constellation symbols are replaced in the generator matrix of the OSTBC to generate the codeword. Then, the elements of the tth row of the codeword are transmitted from different antennas at time slot t. We assume a quasi-static flat Rayleigh fading model for the channel. Therefore, the path gains are independent complex Gaussian random variables and fixed during the transmission of one block. The receiver utilizes ML decoding to estimate the transmitted symbols and bits. For a fixed constellation and OSTBC, the transmission bit rate is fixed. Then, we use Monte Carlo simulations to derive the bit error rate (BER) versus the received SNR [135].
Simulation results are usually reported for a given transmission bit rate and different number of transmit antennas. To this end, we need to pick the right combination of orthogonal STBC and constellation. If a full rate, R = 1, OSTBC exists for the given number of transmit antennas, we can use the same constellation that we use for the corresponding one transmit antenna. However, if such a full rate OSTBC does not exist, we should pick the combination of the orthogonal STBC with the highest...
