This paper provides a survey for the main challenges of future Research and Development (R&D) for Next Generation mobile Networks (NGNs). It addresses software and hardware re-configurability with focus on reconfigurable coupling and interworking amongst heterogeneous wireless access networks. It also explores the promising technologies for NGNs such as nanotechnology, cloud computing and texting by thinking. The paper then highlights the challenging research areas for enhancing network performance and affordability beginning with All IP network and security issues, Vehicular Ad Hoc NETworks (VANET) and the necessity of high data rates at cell edges. Investigating the viability of cooperative networks and one unified global standard for NGNs, the paper analyzes macro-diversity and advanced multi-cell coordination for mitigating inter-cell interference.