Experimental Characterization and Modeling of Shadow Fading Correlation for Relaying Systems

Abstract

A multi-link measurement campaign with relays was carried out. The shadowing cross-correlations between a BS-MS (Base Station to Mobile Station) link and a RS-MS (Relay Station to Mobile Station) link or between two RS-MS links were experimentally characterized. The correlation coefficients were found to vary from -0.04 to 0.57. Furthermore, based on the significantly large amount of measurement samples, the shadow fading angular properties were examined. It was observed that the correlation of 0.5 was found when the angle θ seen from MS to the transmitters is smaller than 10 degrees. Although correlations observed with the angle θ higher than 10 degrees present different angular dependences, their coefficients are minor and considered as negligible. This result indicates that a correlation coefficient of 0.5 should be taken into account in analysis tools for 0-10 degree angular sample groups. A simple uncorrelated shadow fading model for signals from different transmitters can be used for the other cases.

Shadow Fading Correlation in High-Speed Railway Environments

“…One possible reason is that D in our measurements is always around 3-4 km, which does not cover a sufficiently large range. We also note that, as reported in [35], a clear dependency of crosscorrelation can only be observed when TX/RX separation distance is around 1000 m, which is not a realistic case for HSR deployment. Since we use the operative GSM-R network in the measurements, changing D to have more realizations is not feasible in our current work.…”

Performance Analysis of Amplify-and-Forward Systems with Single Relay Selection in Correlated Environments

“…Similarly, and may also be correlated RVs with a correlation matrix given by when there are common scatterers in the vicinity of the destination. Moreover, in indoor systems or in systems in which the source- and the -destination channels are impinged by the same scatterers, the two channels of the relay can also be correlated with the following correlation matrix [ 8 , 9 , 13 , 15 ]: …”

“…In addition, for any pair of relays and , their channels are independent. It is noteworthy again that the assumption of the correlation between the two channels of each relay is justifiable when (1) there are common scatterers that affect both and [ 9 , 14 , 15 ]; (2) the relays are moving between the source and the destination [ 9 , 22 ]; and (3) when the considered system is deployed in an indoor environment [ 8 ]. The end-to-end SNR at the destination of the selected relay is given by which is bounded as follows [ 23 ] …”

“…Although SRS and related performance analysis have been extensively investigated, most of the existing works assume that wireless channels are statistically independent. However, in reality, wireless channels are likely to be correlated due to feedback delay, common scatterers, geometry of the channels, or characteristics of the channels [ 7 , 8 , 9 ]. Particularly, in wireless cooperative sensor networks, nodes are commonly low-complexity and densely deployed.…”

Outage Probability Analysis of the Relay Network with Correlated Relaying Channels

“…Most of the works in the literature consider the statistically independent cascaded channels [5]. In practice, because the signals experience common scatterers, the channels can be correlated [6], [7], especially in the cooperative sensor networks, where low-complexity nodes are densely deployed. There are various kinds of channel correlations existing in the relay network and the review of such channel correlations has been thoroughly documented in [8].…”