Adaptive techniques in advanced 4G cellular wireless networks

Abstract

The capacity of 4G cellular wireless networks like Long Term Evolution Advanced can be increased by larger bandwidth for multicarrier operation, higher number of antennas for more spatial multiplexing, tighter reuse of radio cells using the same frequency spectrum and optimisation of the network configuration in general. The potentially higher capacity will be achieved only if the whole wireless network can be more or less perfectly adapted to the existing real environment at any time. This real environment which includes for example the radio channel, the user traffic, the equipment performance and the network configuration can change, however, within a time scale of a wide range from below 1 ms up to more than 100 s. Appropriate linear or nonlinear adaptive techniques which are able to track these changes are described for wideband linear power amplifier, multiple input multiple output antenna systems, heterogeneous networks and self-organising networks including the corresponding realisation and performance aspects.