Investigation of Indoor Broadband Propagation Characteristics for Fourth Generation (4G) Mobile Systems

As new parts of the spectrum are being allocated to future wireless systems, it is envisaged that future, beyond 3G, systems will require substantial increases in data rates. Higher data rates for single input-single output systems would impose larger power or smaller range, due to the fundamental requirement of a basic energy per bit relative to the noise level. It has been shown however that sophisticated antenna arrangements can overcome the pathloss problem by beamfocusing, whereas even further increases in data rates can be achieved by sending different data streams over individual antenna elements in the context of multiple input- multiple output (MIMO) systems. This makes MIMO technology a promising alternative for the future. In order to exploit the higher signal bandwidth and advanced antenna concepts, detailed knowledge of the wideband channel behaviour as a function of the environment is necessary. The dimensions of a wireless system are: * power, * time, * bandwidth, * symbol rate, * number of resolvable multi paths, * antenna structure, and * signal design. The optimization of the system design lays in the utilisation of all dimensions to the maximum extent. Moreover, detailed channel knowledge allows for the performance evaluation of any potentially implemented technology. The purpose of the present work is to establish the necessary channel knowledge for carrier frequencies in the 3-5 GHz region, within a 100 MHz bandwidth in indoor environments, where most high data rates applications are envisioned. The problem will be addressed first through an extensive measurement campaign to provide the framework for the modelling effort and second through the analysis of the experimental data and the derivation of empirical models. This work is supported by DoCoMo Euro-Labs. (Jesper Ødum Nielsen, Patrick C.F. Eggers, Jørgen Bach Andersen, Persefoni Kyritsi)