Towards the next generation mobile communications

The range of requirements and challenges characterizing mobile communications include speed of movement combined with demand for high bit-rate, coverage combined with economy of deployment, exploitation of available spectrum combined with system control, etc. These have been faced through designing systems to optimally accommodate particular ranges of the relevant parameters. This has led to a diversity of systems and a fruition of mobile services either confined to isolated systems or severely limited by difficulties in migrating from one system to another and/or in system interoperation.