Research On Overlapped Code Division Multiplexing And Code Searching Over High-Order Modulation

Integer programming is very important in a lot of aspects of our life, such as communication network optimization, investment analysis, production scheduling and so on. In this dissertation, first the background, the main models and solving algorithms in integer programming is studied, then the 0-1 integer programming model and solve program is analyzed. Based on these studies and taking the resource management as the key, we give a thorough and comprehensive study on the resource optimization in relay systems.OFDM (Orthogonal Frequency Division Multiplexing) is a parallel transmit technique. By dividing the frequency-selective channel into a number of orthogonal sub-channels, OFDM could eliminate the interference among signals and improve the system capacity. On the other hand, the research of relay systems is becoming more and more important in future wireless communications since it could increase the system throughput and coverage. Thus, in this dissertation, an OFDM-based relay system is considered and the subcarrier-routing allocation problem is solved. By abstracting this allocation issue with traditional 0-1 integer programming models, we construct an optimization problem, in which the goal is to maximize the overall system throughput, with restrictions that one subcarrier can only be used by one user in one routing, and each user has to meet a minimum data rate.Based on current allocation algorithms in cellular networks, a joint subcarrier-routing allocation algorithm is proposed. We map the original three-dimensional problem into a two-dimensional plane to reduce the complexity. The selection of the best routing is included in this mapping step. Compared with current algorithms, the proposed scheme is flexible and with higher performance, while the computation is reduced.