Resource allocation schemes for throughput enhancement and QoS in OFDMA systems

Abstract

The growing need of multimedia applications requires high-speed transmission technique and efficient resource management scheme for the next generation mobile communication. Therefore, any scheme guaranteeing the Quality of Service(QoS) in multimedia environment has been focussed in the context of radio resource management(RRM). To guarantee QoS and enhance system throughput under various traffic environment, we propose two kinds of resource management schemes such as packet-by-packet scheduling and contention-free subchannel allocation scheme. Scheduler must compromise between throughput maximization and fairness while guaranteeing various QoS requirements. Most of the previous approaches in scheduling are focussed on which user take more higher priority than other users. In case of user based schedulers, however, they have trouble to guarantee the QoS of each multimedia service because if a user who has the highest priority has a large amount of packets, it is possible that other users do not take a chance to transmit their data. Therefore, we propose a packet-by-packet scheduling algorithm which grants priority to each packet instead of a user. The proposed scheduler classifies packets inside of each user into three classes such as emergency, near emergency, and non-emergency packets based on packet delay ratio, and applies different scheduling schemes to grant priority in each region respectively. It can be possible to manage packets more efficiently for guaranteeing various Quality of Services (QoS) in wireless multimedia systems. Simulation results show that the proposed scheme offers higher system throughput and lower packet drop rate than other scheduling algorithms. In orthogonal frequency division multiplexing access(OFDMA) system, it divides a whole channel into narrowband subcarriers to support a high data rate and to avoid frequency-selective fading. Furthermore, different subcarriers can be allocated to different users to provide a multiuser...