In this article, we investigate the potential enhancements in signal reliability which can be achieved using a millimeter-wave distributed antenna system (DAS) within an indoor environment. To achieve this, we measured the signal power simultaneously received at nine ceiling-mounted access point (AP) locations likely to be used in future indoor DAS deployments while a mobile user imitated making a voice call on a hypothetical user equipment. Key metrics, associated with the performance of multiple antenna systems, such as the cross correlation coefficient (CCC) and channel power imbalance (CPI) are determined. It was found that line-of-sight (LOS) and quasi-LOS (QLOS) links with the APs typically led to higher CCC values than the non-LOS (NLOS) cases. Similarly, LOS and QLOS links typically produced higher CPI values between APs than the NLOS case. To enable the reproduction of our results, we have successfully applied autoregressive moving average and autoregressive integrated moving average modeling to the CCC and CPI time series. The performance improvement that can be achieved using a DAS instead of a single AP was evaluated using three commonly deployed diversity combining schemes, namely, selection combining, equal gain combining, and maximal ratio combining along with three AP selection mechanisms, namely, per-sample random AP selection, one-shot AP selection, and per-sample optimal AP selection. Finally, we have provided some useful insight into the influence of differing AP numbers on the diversity gain when considering the aforementioned AP selection methods.
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FunderThis work was supported in part by the Northern Ireland Department for the Economy as part of the U.S.-Ireland ?Enabling Cellular Networks to Exploit Millimeter-wave Opportunities (NEMOs)? project under Grant USI080. The work of Hien Quoc Ngo was supported by the U.K. Research and Innovation Future Leaders Fellowships under Grant MR/S017666/1.
- Antenna measurements
- Autoregressive integrated moving average (ARIMA) modeling
- Diversity methods
- Diversity reception
- Power measurement
- Time measurement
- autoregressive moving average (ARMA) modeling
- channel measurement
- channel power imbalance
- distributed antenna system
- diversity gain
- millimeter wave
- time series analysis
ASJC Scopus subject areas
- Electrical and Electronic Engineering