Modeling and Characterization of the Wireless Channel
The performance of communication systems heavily depends on the channel over which communication takes place. In order to allow for an accurate performance prediction of these systems and the used algorithms, detailed knowledge about the channel is necessary. On the other hand, not all the details of the propagation environment are required: It should only contain the information relevant for a systematic design of the communication system and an evaluation of the algorithms. Thus, channel modeling is always the result of a trade-off between a detailed representation of the environment and mathematical tractability.
In order to gain access to realistic channel information, an extensive channel measurement campaign has been performed in cooperation with the Electronic Measurement Research Lab of the TU Ilmenau. The measurement campaign characterizes a typical multiuser and multicell MIMO wireless channel in an urban macro cell scenario for the Long Term Evolution (LTE) standard. Channel sounding has been conducted around 2.53 GHz in 2 bands of 45 MHz. Different base station positions and heights have been used to measure the MIMO channel on a multitude of mobile tracks, see Figure 1.
While wireless channel modeling has made significant progress in the past years, many channel properties of multiuser and multicell MIMO systems are still not properly captured. Examples are the inherent non-stationarity in time, frequency, and space of the channel as well as correlation properties of large scale channel parameters as, e.g., shadow fading. These aspects are, however, highly relevant for the design of wireless communication systems, especially in the context of cooperative networks. Identifying and analyzing the key characteristics of the wireless channel is the focus of this project.
Ispas, A., Schneider, C., Ascheid, G. and Thomä, R.: Analysis of the Local Quasi-Stationarity of Measured Dual-Polarized MIMO Channels, In IEEE Trans. Veh. Technol. 2014, 10.1109/TVT.2014.2358942 ©2014 IEEE
Ispas, A., Gong, X., Schneider, C., Ascheid, G. and Thomä, R.: Dual-Polarized Ricean MIMO Channels: Modeling and Performance Assessment, In IEEE Trans. Commun. Vol. 61 , p.p. 4218-4231 , No. 10 Oct/2013, ISSN: 0090-6778, 10.1109/TCOMM.2013.082813.120976 ©2013 IEEE
Ispas, A., Dörpinghaus, M., Ascheid, G. and Zemen, T.: Characterization of Non-Stationary Channels Using Mismatched Wiener Filtering, In IEEE Trans. Signal Process. Vol. 61 , p.p. 274-288 , No. 2 Jan/2013, 10.1109/TSP.2012.2223688 ©2013 IEEE
Ispas, A., Gong, X., Schneider, C., Ascheid, G. and Thomä, R.: Modeling and Performance Evaluation for Dual-Polarized Ricean MIMO Channels, in Proc. IEEE Global Commun. Conf. (GLOBECOM) , (Anaheim, CA, USA) Dec/2012 ©2012 IEEE
Ispas, A., Sun, C., Schneider, C., Gong, X., Ascheid, G. and Thomä, R.: Impact of Polarization on the Achievable Rate of MIMO Systems with Linear Receivers, in Proc. 23rd IEEE Int. Symp. Personal, Indoor, Mobile Radio Commun. (PIMRC) , (Sydney, Australia) Sep/2012, 10.1109/PIMRC.2012.6362690 ©2012 IEEE
Ispas, A., Hoelscher, J., Gong, X., Schneider, C., Ascheid, G. and Thomä, R.: Modeling and Performance Evaluation for Mobile Ricean MIMO Channels, in Proc. IEEE Int. Conf. Commun. (ICC) , (Ottawa, Canada) Jun/2012, 10.1109/ICC.2012.6363749 ©2012 IEEE
Ispas, A., Schneider, C., Ascheid, G. and Thomä, R.: Performance Evaluation of Downlink Beamforming over Non-Stationary Channels with Interference, in Proc. 22nd IEEE Int. Symp. Personal, Indoor, Mobile Radio Commun. (PIMRC) , (Toronto, Canada) Sep/2011, 10.1109/PIMRC.2011.6139790 ©2011 IEEE
Ispas, A., Schneider, C., Dartmann, G., Gong, X., Ascheid, G. and Thomä, R.: Analysis of Mismatched Downlink Beamforming over Non-Stationary Channels with Interference, in Proc. XXX General Assembly Scientific Symp. Int. Union Radio Science (URSI) , (Istanbul, Turkey) Aug/2011, 10.1109/URSIGASS.2011.6050576 ©2011 IEEE
Ispas, A., Bernadó, L., Dörpinghaus, M., Ascheid, G. and Zemen, T.: On the Use of Mismatched Wiener Filtering for the Characterization of Non-Stationary Channels, in Proc. 44th Annu. Asilomar Conf. Signals, Syst., Comput. , p.p. 1971-1975 , (Pacific Grove, CA, USA) Nov/2010, ISSN: 1058-6393, 10.1109/ACSSC.2010.5757885
Ispas, A., Schneider, C., Ascheid, G. and Thomä, R.: On Non-Stationary Urban Macrocell Channels in a Cooperative Downlink Beamforming Scenario, in Proc. 72nd IEEE Veh. Tech. Conf. (VTC 2010-Fall) , (Ottawa, Canada) Sep/2010, 10.1109/VETECF.2010.5594355 ©2010 IEEE
Ispas, A., Schneider, C., Ascheid, G. and Thomä, R.: Analysis of Local Quasi-Stationarity Regions in an Urban Macrocell Scenario, in Proc. 71st IEEE Veh. Tech. Conf. (VTC 2010-Spring) , (Taipei, Taiwan) May/2010, 10.1109/VETECS.2010.5494098 ©2010 IEEE