Analysis and Design of Radio Interference Avoidance Mechanism for 3GPP LTE Femtocell

Minimizing femtocell interference, maximizing resource efficiency and ensuring quality of service (QoS) are important challenges in the design of protocols for femtocell networks. Techniques of interference avoidance, resource efficiency improvement, and QoS guarantee consist in finding an optimal assignment of physical resource blocks (PRBs). For example, in dense area deployments, only resources that are not occupied by interfering neighbors can be assigned with considerations of employed resources and required service qualities. In this thesis, we address the optimal PRB assignments in orthogonal frequency division multiple access (OFDMA) femtocell networks. Typically, all femtocells operate in the co-channel deployment, and schedule for different connections dynamically. We seek a resource-optimal distribution that maximizes spectral efficiency while ensuring simultaneous femtocell connectivity quality to femtocell management systems, which are constrained to form an interference graph used as an assignment distribution. First, we formulate this problem as an Integer Linear Programming model. Then, we implement a greedy algorithm to solve the allocation problems. Experimental results show that the proposed model provides optimal spectral efficiency values according to the dynamic femtocell loading.