We present and demonstrate mathematical modelling and optimization algorithm for enhancing HSDPA performance by automatically linking Common Pilot Channel (CPICH) power to HSDPA transmit power. Our approach uses non-uniformly allocated CPICH power and focuses on HSDPA performance with the side constraint of R99 soft handover. Solving the mathematical model gives the optimal CPICH allocation for small networks. The optimization algorithm demonstrates itself very time efficient in dealing with large scale networks which might have hundreds of cells and tens of thousands of users. A case study of realistic network planning scenario for Berlin shows significant CPICH power saving and HSDPA performance improvement.