Comparison of Outdoor to Indoor and Indoor to Outdoor MIMO Propagation Characteristics at 5.25 GHz

An Empirical Study on Channel Reciprocity in TDD and FDD Systems

“…The maximum difference in RMS delay spread is observed to Ref. [14] analyzes the reciprocity of RMS delay spread in outdoor-to-indoor (O2I) and indoor-to-outdoor (I2O) scenarios. In the O2I scenario, the mean RMS delay spread is 40 ns, while in I2O scenarios, it is 34 ns.…”

“…Various studies have analyzed the reciprocity of TDD/FDD systems through extensive channel measurements. In TDD systems, factors such as human movement, vehicular traffic [13], transceiver environments, and antenna height [14] can disrupt channel reciprocity. Furthermore, the analysis of the channel matrix obtained from measurements of the TDD prototype system indicates that as the channel from line-of-sight (LoS) to partial obstruction by foliage, and further to full-blocked non-line-of-sight (NLoS), the channel correlation gradually diminishes [15].…”

“…This stems from several factors: first, the accuracy and impartiality of the channel measurement campaigns are lacking. These measurements do not sufficiently eliminate the influences of radio frequency links and transceiver antennas [15], and fail to ensure the static nature of the measurement scenarios [14]; Second, an inequitable post-processing of channel measurement raw data introduces bias in reciprocity analysis. For instance, the extraction and denoising of channel impulse response (CIR) [19]; Additionally, assessing reciprocity solely from a single aspect or metric makes it challenging to accurately determine channel reciprocity [20]; Finally, there has not been a sufficiently in-depth exploration of the factors influencing reciprocity from the perspective of physical propagation of radio waves, particularly in terms of multipath components (MPCs).…”

“…For instance, the extraction and denoising of channel impulse response (CIR) [19]; Additionally, assessing reciprocity solely from a single aspect or metric makes it challenging to accurately determine channel reciprocity [20]; Finally, there has not been a sufficiently in-depth exploration of the factors influencing reciprocity from the perspective of physical propagation of radio waves, particularly in terms of multipath components (MPCs). Most of the existing studies focus on channel statistical characteristics, encompassing path loss, shadow fading, root mean square (RMS) delay spread, angle spread, and others [14], [16], [18]. However, the power delay profile (PDP) and power angular delay profile (PADP), which carry information about parameters such as multipath power, delay, and angles, have not been thoroughly investigated.…”

Esquema de transmissão alamouti implementado em rádio definido por software

“…Para este trabalho o SDR foi uma maneira muito adequada para se implementar o sistema e que permitiu a construção de uma plataforma de testes que tem o objetivo de analisar o algoritmo de codificação espaço-temporal Alamouti [19]. Esta plataforma de testes foi implementada utilizandose software e uma interface com hardware.…”