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  1. J. Melasniemi, Size-based scheduling under terminal constraints in cellular systems, Aalto University School of Science and Technology, 2010, Master's Thesis (pdf)(bib)
    Abstract: The traffic volume of mobile data has been increasing while the third generation of mobile communication systems (3G) and its evolution versions such as High Speed Downlink Packet Access (HSDPA) have increased the transmission rates of mobile networks. In cellular networks it is not possible to serve all users simultaneously and the system schedules the transmissions by selecting the service order of users in the system. In HSDPA-like systems the transmissions of users are separated by codes, that is the systems are based on Code Division Multiple Access (CDMA) technology. User devices are categorized by the number of codes each device is able to use at maximum. In this thesis, the scheduling aspect of improving the performance of wireless systems is examined. The service order of jobs in the system is defined by the scheduling policy. By changing this policy, it is possible to change the behaviour of the system considerably. Earlier it has been proven that the Shortest Remaining Processing Time (SRPT) policy is the optimal way of minimizing the mean delay of the M/G/1 queue. In this thesis, the SRPT policy is under examination when terminal constraints are taken into account. This results in multi-server queuing models for which hardly any optimal scheduling results are known. The results achieved by simulating the wireless cellular system at flow level show that the performance of the system is improved by using SRPT instead of Processor Sharing, the fair baseline policy. The performance improvement depends on the load of the system together with the number of codes in the system. The performance improvement is higher when the system is under high loads.