High resolution parameter estimation for millimeter wave propagation in dynamic scenarios

• Applicant: Professor Dr.-Ing. Reiner Thomä
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering
• Term: from 2019 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 418074791

Future mobile radio systems of the 5th generation will use frequencies in the millimeter wave frequency range with bandwidths up to several GHz. To achieve a reasonable link budget, very large ("massive") antenna arrays are required. These inevitably have a high directivity, which must be adjusted in an adaptive way. For the prediction and evaluation of the performance of such systems, there are no channel models available. This is mainly because of the lack of suitable channel measurements, which would allow determining the propagation directions of the electromagnetic waves on the transmitter and receiver side, their propagation time, Doppler shift, and polarization orientation with the necessary resolution in dynamic scenarios along the trajectory of the mobile station. The aim of this project is therefore research towards a high-resolution parameter estimator based upon to the maximum likelihood principle, which solves this problem in the context of a specific antenna array architecture. The data model of the parameter estimator takes into account the fact that directions, time-of-flight and Doppler do no longer exist in a factorizable form. This overcomes the conventional narrow-band assumption and requires a consistent description of the array in the time domain, which involves new design paradigms for the antenna elements and their arrangement with regard to the diameter and antenna spacing. In order to meet the special challenges of highly time-variant scenarios, the propagation paths have to be tracked by Bayesian filters. For this purpose, methods of multi-target tracking in Radar are used, which are adapted for the estimation task presented here.As a result, we expect advantages, such as reduced computational complexity, higher accuracy, and resolutions of ambiguities, which may result from the special array design and the non-factorizable data model. This will be accompanied by a practical approach for the adaptation of the model order, the evaluation of the "lifetime" of propagation paths and their sustained tracking in case of short-term shadowing.In this context, novel methods will be developed, which will allow new insights for channel modeling. These include models for the description of specular and diffuse (non-resolvable) components of wave propagation, their polarimetric modeling and the dynamic relationship in the dimensions direction, time and Doppler. Finally, we aim at statistical descriptions of clusters, which cannot be determined by conventional methods of spatial and temporal resolution, but are required for channel modeling.

• DFG Programme: Research Grants