A Study of OFDMA Access Method in Multi-path Fading Channel

In this paper, OFDMA (Orthogonal Frequency Division Multiple Access) access methods based on PF (Proportional Fair) algorithm considering the fairness among MS (Mobile Stations) and the total throughput were studied. Concretely, four types of scheduling methods were proposed. Computer simulations were carried out with four types of proposed methods in order to clarify the performance. As the result of computer simulations, the following things have been clarified: monitoring channel quality with 2-level indicator achieved efficient throughput performance, an MS sequential selection method based on the amount of channel allocation requests was the best performance for the throughput, a sub-carrier sequential selection method based on the instantaneous SINR (Signal to Interference Noise Ratio) was the best performance for the fairness among four types of proposed scheduling methods, and the proposed scheduling method with 2-level channel quality monitoring was efficient in case where fading interval was 10 times or more longer than the average delay-time which is the time interval between a request of sub-channel allocation by an MS and establishment of a UL (Up Link) data transmission.