P-CPICH power and antenna tilt optimization in UMTS networks

Abstract

Pilot power optimization in UMTS networks is a crucial engineering issue which has been receiving increasing interest. It has been shown that the optimization approach to assigning the P-CPICH (primary common pilot channel) power levels facilitates coverage control and improves significantly radio resource utilization in UMTS networks. Combined with optimization of radio base station antenna tilt, this becomes a powerful tool that allows the total interference level in the network to be significantly reduced and the network capacity to be very efficiently improved. The paper addresses the pilot power and antenna tilt optimization problem and presents an efficient algorithm that optimizes the antenna downtilt setting in the network such that the total P-CPICH power is minimized. A case study has been done for a network scenario based on real data for the city of Lisbon. The numerical results demonstrate that the optimized antenna tilting can give a reduction of up to 50% in the optimal pilot power levels.