Research On Dynamic Resource Allocation Algorithm In Multiuser OFDM System And Its Verification

One of the main objectives in future wireless networks is to provide high-rate data services with satisfying QoS (Quality of Service) and fairness over time-varying, frequency selective fading and band-limited wireless channels. Orthogonal Frequency Division Multiplexing (OFDM) combined with dynamic resource allocation method is one of the most potential techniques to satisfy this need.This thesis focuses on the dynamic resource allocation algorithms in multiuser OFDM system and their hardware verification with multicore DSP platform. Firstly, the optimizing model of multiuser OFDM systems has been established, and the dynamic power allocation algorithms with fixed transmission rate, namely Margin Adaptive (MA) algorithms, have been analyzed. Furthermore, a novel suboptimal MA Greedy algorithm based on demand function has been proposed to reduce the computing complexity with subscribers' fairness and QoS guaranteed. Utilizing the simulation of real-time services, we have proved that compared to static allocation algorithms, the proposed MA Greedy algorithm could enhance the system performance by 5-6dB with low computing complexity, which is very close to the optimal MA algorithm.Subsequently, the mathematic model of rate adaptive (RA) algorithms which aims for maximizing the overall system capacity under the constraint of fixed total transmitting power has been built. Then, a suboptimal fairness algorithm based on demand function has been put forward to improve the system capacity. In this algorithm, the allocation process is divided into two separate steps, resource calculation and subcarrier allocation. With the employment of multiuser diversity scheduling and the Greedy bit allocation algorithm, this algorithm could implement high system throughput and proportional fairness with low computing complexity. Through the simulation with non-real-time services, we proved that with the fairness of subscribers guaranteed, the proposed suboptimal fairness algorithm could provide a higher overall performance to OFDM systems than the optimal fairness algorithm.Finally, a preliminary scheme has been provided to verify the feasibility and validity of proposed RA algorithm. The result showed that the algorithm operate well on the selected multicore DSP platform.