the imple- technique for instance uses the eigenstructure of the mentation of a direction-of-arrival scheme as the ESPRIT covariance matrix. In contrast, the ESPRIT exploits the technique, the channel degradation due to small-scaling rotational invariance of the underlying signal subspace. fading effects must be available. Taking into account the The last class of methods is the ML technique, which also processing delay caused by the information feedback performs well under low signal-to-noise ratios. The between receiver and transmitter and the adaptation SAGE algorithm is a way of ordering the maximum process itself, the channel variations must be predicted likelihood approach in an appropriate way. reliably into the future as far as possible. In this paper, This subsection is organised as follows. First, new re- the feasibility of a 2-dimensional fading forecast is sults of the MUSIC algorithm will be shown, followed by studied in the context of the ESPRIT. the reporting on the use of the ESPRIT technique. The Next, the SAGE algorithm is investigated. The most common technique with high resolution is of course SAGE optimisation algorithm is used to replace the the SAGE algorithm. Theoretical and experimental results high-dimensional optimisation procedure necessary to of the implementation of the algorithm in the time domain compute the joint maximum likelihood estimate of the will be shown. Also the implementation of the SAGE in parameters by several separate maximisation processes, the frequency domain with important adaptations will be which can be performed sequentially. demonstrated with simulations and measurements. Here, a technique derived from the ML principle is The MUSIC algorithm is a high resolution signal proposed. It allows for high resolution determination of parameter estimation technique. It exploits the eigen- the complex signals. The EM algorithm updates all pa- structure of the input covariance matrix, based on a geo- rameters simultaneously, which implies a slow conver- metric view of the