I. Introduction
The introduction of self-organization in next generation cellular networks, e.g. Long Term Evolution (LTE), offers a great potential, for network operators to reduce operational costs and enhance resource efficiency, and for users to experience high quality of service (QoS) at lower prices. Therefore, next generation cellular networks will exhibit a significant degree of self-organization, as also recognized by 3rd Generation Partnership Project (3GPP) [1] and Next Generation Mobile Networks (NGMN) [2].