Self-optimization of Antenna Tilt in Mobile Networks

Abstract: The increased complexity of mobile networks, the need to deliver high data rate services and the variation of mobile traffic put a high burden on operation and maintenance in terms of extra workload and additional costs . New approaches to network optimization and management should be taken into account to increase network performance and reduce operational costs. Antenna tilt is a powerful parameter for optimization of a mobile network. It has direct impact on shaping the boundary of the serving cell and hence on the coverage and interference parameters of the network. With the introduction of Remote Electrical Tilt (RET) antennas, tilt optimization can be used in the context of self-optimization. This work discusses how base station antenna tilt can be used as a self-optimization tool for load-balancing and presents a framework for a self-optimization process that can be integrated into existing and future mobile networks. Tests using real traffic data proved that the self-optimization process can be used to correctly identify congested cells. Both link level and system level simulations are performed to determine the impact of tilt adjustments on network performance. The results show that antenna tilt can be an effective tool to achieve load-balance between neighbouring cells and thus increase the Grade of Service (GoS). Furthermore, different tilt adjustment procedures are discussed each with it's advantages and disadvantages. It is concluded that antenna tilt can be successfully used for self-optimization purposes and possible limitations and issues are discussed.