Research On Packet Scheduling In Mobile Communication Systems

Data service is becoming the main service in future mobile communication systems. Packet scheduling, allocating resource for packet transmission, is an important part to enhance system throughput, ensure fairness and meet the Quality of Service (QoS). Wireless packet scheduling has been a key technology in radio resource management (RRM).There are some special characteristics in wireless communication systems compared with wire systems, such as time-varying channel, frequency band limited and so on. Therefore, packet scheduling algorithms for wire environments are not suitable for wireless communication systems. First, the related theory and algorithms are expounded. Then, several algorithms, including Idealized Wireless Fair Queuing (IWFQ) algorithm, Channel State Dependent Packet Scheduling (CSDPS) and Server Based Fairness Algorithm (SBFA), are analyzed. The study focuses on wireless packet scheduling algorithms in the 3^rd generation mobile communication system (3G), including round robin, max C/I and proportional fairness algorithm. To evaluate system performance and fairness of these algorithms, a simulation software platform of uplink transmission, based on DFT-SOFDM and combined with link adaptation techniques, is established. The link adaptation techniques include adaptive modulation and coding (AMC) and hybrid auto-retransmission request (HARQ). The challenges packet scheduling needs to face in the future mobile communication systems are discussed at last.