Interference functions - A mathematical framework for MIMO interference networks

This chapter discusses a general mathematical framework, namely interference functions, that can be used to solve different optimization problems in MIMO interference networks, with a special emphasis on power control. It provides a review of multiuser MIMO channels with an overview on some key concepts for multiuser MIMO systems, with a special emphasis on beamforming. It discusses some practical examples of interference functions. These are special cases of the more general mathematical framework of interference functions. It introduces and discusses the axiomatic framework of interference functions. The framework of interference functions provides a unifying model that captures core properties of typical interference scenarios. It shows how properties of interference functions can be exploited for the development of iterative algorithms. Interference will be the key performance limiting factor for many future deployment scenarios. But the development of dynamic techn iques for interference mitigation/ avoidance and subchannel allocation hinges on how efficiently channel state information can be exchanged in the network. This is especially true for distributed networks, where information exchange between nodes is very limited. Examples are macro cells with unplanned pico/femto cells, relays, or ad-hoc networks.