Long term evolution (LTE) provides global mobility with a wide range of services that includes voice, data and video in a mobile environment with lower deployment costs. Mobile networks are rapidly transforming – traffic growth, increased bit rates per user etc., due to new technologies such as LTE. The growth in mobile traffic is mainly driven by devices such as smartphones, tablets, etc. In order to get the best performance out of an LTE network, it needs to be optimized continuously. This white paper addresses the wireless network optimization challenges from a radio network perspective. Key performance indicators (KPIs) and with their dependence on performance indicators (PIs), field measurement metrics and parameters are described in the correct context.