A Study On The Performance Of Adaptive Multiresolution MQAM In Cooperative Communication Systems

Future-generation wireless multimedia communication requires the ability to transmit many kinds of messages simultaneously. Different messages have different quality requirement. Adaptive multiresolution M-ary quadrature amplitude modulation (MR-MQAM) can provide unequal error protection to different messages according to their importance, which can greatly increase the spectral efficiency of wireless communication systems. Multiple-input multiple-output (MIMO) technique based on singular value decomposition (SVD) and MIMO maximal ratio combining (MRC) technique can provide multiplexing gain and diversity gain, respectively. Combining these two kinds of MIMO techniques and adaptive MR-MQAM can further improve the spectral efficiency of wireless communication systems. Dual-hop relaying transmission technique can effectively combat the effect of channel fading, expand the coverage of wireless communication systems without requiring additional power. The application of adaptive MR-MQAM scheme based on SVD in dual-hop relaying transmission systems employing decode-and-forward (DF) protocol can further improve system performance. Therefore, this thesis studies the performance of adaptive MQAM/MR-MQAM systems based on SVD, adaptive MR-MQAM systems using MIMO MRC, and adaptive MR-MQAM dual-hop relaying systems based on SVD over fading channels.Chapter1is a review of adaptive modulation, adaptive multiresolution modulation, adaptive modulation in MIMO systems, and adaptive modulation in cooperative communication.Chapter2derives the closed-form expressions of outage probability, average bit error rate (BER), and/or average spectral efficiency for adaptive MQAM systems and adaptive MR-16QAM systems based on SVD over Nakagami fading channels, respectively. Numerical and simulation results show adaptive MQAM/MR-MQAM schemes based on SVD can significantly improve the average spectral efficiency for systems.Chapter3studies adaptive MR-64QAM systems for simultaneous voice and two different classes of data transmission using MIMO MRC over Rayleigh fading channels. The closed-form expressions of outage probability, average spectral efficiency, and average BER for voice and two different classes of data are derived. Numerical and simulation results show that for a fixed total number of transmit/receive antennas, MIMO MRC systems with more uniform distributed transmit/receive antennas can provide better system performance including outage probability, average spectral efficiency, and average BER; for a fixed product of transmit/receive antennas, MIMO MRC systems with larger total number of transmit/receive antennas can also provide better performance. Chapter4investigates adaptive MR-64QAM dual-hop DF relay systems for simultaneous voice and two different classes of data transmission based on SVD over Rayleigh fading channels. The closed-form expressions of outage probability, average spectral efficiency, and average BER for voice and two different classes of data are derived. Numerical and simulation results show the adaptive MR-64QAM scheme based on SVD can also greatly improve the average spectral efficiency of dual-hop relaying systems.Chapter5concludes the thesis.