Adaptive space-frequency coding for multiple-input and multiple-output orthogonal frequency division multiplexing systems (MIMOs, Trellis codes)

The topic of this dissertation is to design, evaluate and simulate adaptive algorithms for systems with multiple transmit and receive antennas using the Orthogonal Frequency Division Multiplexing (OFDM) technique.; OFDM is a candidate for the 4th Generation telecommunication systems, which are currently under standardization. Systems having several transmit and receive antennas commonly referred to as Multiple-Input Multiple-Output (MIMO) systems have a significant capacity. This capacity can be exploited to provide some sort of diversity, i.e., a replica of the transmitted signal. According to the domains, where the diversity is applied, we talk about Space-Time (ST), Space-Frequency (SF) or Space-Time-Frequency (STF) coding. The combination of MIMO and OFDM is a new attractive approach for next generation communication systems.; In our studies, we go a step further by considering adaptation of SF codes for MIMO OFDM systems. We design adaptive algorithms that exploit the Channel State Information (CSI) available at the transmitter by adapting the transmitted signals in order to improve the signal reception and detection and, hence, enhance the system's performance. This property of the system is known as adaptivity.; We investigate three distinct adaptive algorithms, which are based on Space-Frequency Block (SFB) codes. At first, we evaluate the performance of SFB codes when the transmitted signal is adapted according to a common Bit Loading (BL) technique. We then examine Transmit Selection Diversity (TSD) for the adaptation of the transmission. We finally propose a novel algorithm that is based on the selection of distinct SFB code. We refer to this algorithm by Code Rate Selection (CRS).; We consider state of the art adaptive algorithms for Space-Frequency Convolutional (SFC) codes that have not been presented so far in the literature. We initially investigate adaptation of these codes with TSD. We then propose two distinctive approaches for adaptation of SFC codes with BL technique depending if the trellis representations used for encoding and decoding have a fixed or variable number of states.