Research On The OFDM Resource Allocation Algorithm Based On Relaying

Recently, the mobile internet has experienced an explosive development, and the massive dataprocessing requires more efficient wireless technology urgently. Both the OFDM and the relayingcome into people’s view. OFDM is well known for its high bandwidth efficiency, while relaying isused to cover the edge of the cells. The combination of the two techniques has a great expectation inthe next generation mobile communication system.This thesis mainly researches the resource allocation for wireless-relaying OFDM system. Thebasic theories of the OFDM and the relaying are presented, and the traditional algorithms areanalyzed through simulations. The emphasis is laid on the resource allocation of the single-relayOFDM system, the single-cell relaying OFDM system and the multi-cell relaying OFDM system.Firstly, a symbol-joint resource allocation (J-SRA) with asymptotical fairness is proposed forOFDM systems based on the marginal adaptive (MA) principle, which is composed of two stages.In the first stage, all the users are allowed to use the subcarriers as if in a single-user system. In thesecond stage, the subcarriers occupied by over one user will be arbitrated to some user. It greatlyexploits the time diversity by optimizing the subcarrier and power allocation for the successive Nsymbols in time-frequency two-dimensional domain. The simulation results show that the proposedscheme achieves a better performance than the traditional MA algorithm.The downlink resource allocation of OFDMA system with DF relaying is investigated and theContinuous Resource Allocation (CRA) is proposed. A non-convex optimization problemmaximizing system throughput with users’ satisfaction constraints is formulated with joint relayselection, subcarrier assignment and power allocation. We first transform it to a standard convexproblem and then solve it by the bisection method in the dual domain. The solution is continuousand offers the upper bound of the system throughput. Based on the continuous solution, twoimproved versions TSRA and JRA are derived by some approximation and simplification, both ofwhich are shown to outperform traditional schemes by the simulation results.Finally, a low-complexity distributed allocation scheme aiming at maximize the system weightedsum rate is proposed for multi-cell relaying OFDMA networks. It helps the cells communicate andcooperate implicitly with one another, which decreases the signaling and computational overheadgreatly. Simulation results show that the algorithm converges fast, and outperforms some traditionalschemes in terms of system throughput. Besides, it achieves fair and ubiquitous data coverage forheterogeneous users.