Hücresel ağlarda servis kalitesi kısıtları altında yarı kalıcı çizelgeleme

The dramatic growth of machine-to-machine (M2M) communication in cellular networks brings the challenge of satisfying the Quality of Service (QoS) requirements of a large number of machine-type communication (MTC) devices with limited radio resources. In this thesis, an optimization framework for semi-persistent scheduling of M2M transmissions based on the exploitation of the periodicity of their transmissions with the goal of reducing the overhead of connection and scheduling is proposed. Semi-persistent scheduling allows decreasing the overhead of the signaling required for connection initiation and scheduling.The goal of the optimization problem is to minimize the number of frequency bands used by MTC devices to allow fair resource allocation of newly joining machines and human-to-human communications. The constraints of the problem are jitter and periodicity requirements of MTC devices. The optimization problem is proved to be NP-hard. We first propose an efficient fathoming-based smart enumeration algorithm to find the optimal solution. Then, we propose a polynomial-time heuristic algorithm employing a fixed priority assignment according to QoS characteristics of devices. We prove that this heuristic algorithm provide an asymptotic approximation ratio of 2.33 to the optimal solution for the case where the jitter tolerance of devices are equal to their periods. We also propose a call admission control scheme to dynamically manage the scheduling of newly joining devices. Through extensive simulations, we demonstrate that the proposed algorithm performs better than the existing algorithms by providing a greater efficiency in frequency band usage and satisfying QoS requirements of MTC devices.