Radio Resource Optimization for OFDM-based Broadband Cellular Systems

Abstract: The rapid growth of users’ traffic demand in broadband wireless communication systems requires high-speed data transmission and intelligent resource allocation approaches. The Third Generation Partnership Project-Long Term Evolution (3GPPLTE) has standardized multiple access (MA) schemes for 4G cellular networks. Two advanced schemes, orthogonal frequency division multiple access (OFDMA) and single carrier frequency division multiple access (SC-FDMA), have been adopted for downlink and uplink, respectively.Optimization-based approaches play a crucial role in network operation and resource management. The optimization problems considered in this thesis are addressed in four research papers. For the single cell scenario, the optimization problems of joint power and channel allocation in OFDMA and consecutive-channel assignment in SCFDMA are investigated in Papers I, II, and III. For the OFDM-based multi-cell scenario, an energy minimization problem is addressed in Paper IV.In the thesis, theoretical analysis, algorithm development, and numerical studies are carried out. Mathematical optimization is applied as the main approach to facilitate the problem solving. In Paper I, we evaluate the performance gain and loss for various  allocation policies in the OFDMA system. In Papers II and III, resource allocation algorithms are proposed to obtain competitive and high-quality solutions for consecutive-channel allocation problems in the SC-FDMA system. The theoretical analysis and the proposed algorithm in Paper IV provide optimal solution for energy minimization.