Auto-Calibrated MIMO-OFDM Channel Sounder for 3D Spatial Channel

This paper presents an improved test-bed designed for analyzing the spatial behaviour of wideband indoor channels using MIMO-OFDM systems. A 3D antenna positioning system (3-DAPS) is specifically designed for obtaining 3D spatial data. Also, it allows carrying out some measurements in the range of correlation distance where fading of the radio channel link is significant for indoor scenarios. Special emphasize is made on the RF calibration module, which is designed to track the frequency response of all RF chain of transmitter and receiver and apply those responses to the channel measurements. The average of the pseudo-spectrum MUSIC over all frequencies improves the resolution of the spatial spectrum giving clear peaks where a signal source is and smoothing fake peaks coming from scatters

A Wideband OFDM MIMO Measurement System for Antenna Evaluation

An OFDM-MIMO testbed based on a SDR platform with very flexible antenna positioning system has been designed and presented for WLAN applications. Antenna positioning allows the proper spatial characterization of radio channel links in real scenarios where future wireless networks will be deployed. Some measurements in real indoor scenarios proving reconfigurable antennas are been carried out leading to some interesting results that will be presented in the conferenc

A 2x2 MIMO DVB-T2 System: Design, New Channel Estimation Scheme and Measurements With Polarization Diversity

The increasing interest in MIMO (Multiple-Input Multiple-Output) systems has given rise to a prolific research activity in recent years. Both theoretical and practical issues have been studied. However, so far few MIMO testbeds or prototypes have been built for DVB-T or future standards. In this paper, a novel 2 × 2 MIMO testbed specifically designed for evaluating the performances of a DVB-T2 MIMO system is presented. The description of signal processing is detailed including a new scheme to estimate the MIMO channel matrix. Finally, measurement results with different polarization schemes are presented for typical scenarios, obtaining higher capacity in LoS situations using polarization diversity

Módulo de procesado de señal de un MIMO-testbed OFDM para medidas de antenas reconfigurables

Multiple-Input Multiple-Output (MIMO) systems have been considered as a solution to increase the data rate and quality of signals in the next generation wireless communication systems. The performances of these systems depend on three main aspects: channel propagation characteristics, processing algorithms and antenna array configurations. In order to obtain MIMO channel measurements at ISM band (2.45 GHz) taken into account the use of different antennas such as reconfi- gurables, a MIMO-testbed which uses OFDM technique has been designed and implemented in order to carry out the measurements in indoor scenarios. In this paper, the signal processing module is described which is based on Software-Radio platfor

Keyhole estimation of a MIMO-OFDM train-to-wayside communication system on subway tunnels

This letter presents a deep insight on a real implementation of a train-to-wayside radio on subway tunnels that makes use of a 2 2 multiple-input?multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) setup. The main purpose of this letter is to study in detail the keyhole phenomenon of an MIMO-OFDM train-to-wayside communication system on a tunnel. MIMO keyholes are studied in different tunnels sections, and capacity results are provided. Moreover, we introduce the first keyhole measurements on a railway tunnel. Finally, we follow a quantitative approach to estimate keyhole probabilities on each tunnel stretch and capacity outage curves