Time dispersion characteristics for wideband channel in 28 GHz millimeter wave band for 5G cellular networks

The demand for high data rate transmission for the future wireless communication technology is increasing rapidly. Due to the congestion in the current bands for cellular network, it may not be able to satisfy these requirements. For the future cellular networks, the millimeter wave (mm-wave) bands are the candidate bands because of the large available bandwidth. The 28 GHz band is the strongest candidate for 5G cellular networks. The large bandwidth at this band is one of the main parameters that make the mm-wave bands promising candidate for the future cellular networks. The channel needs to be characterized based on wideband characteristics to know the wideband channel behavior in mm-wave bands. In this paper, the time dispersion parameters at 28 GHz mm-wave band are presented. The wideband channel is characterized based on the root mean square (RMS) delay spread and the mean excess delay that are the main time dispersion parameters. The cumulative distribution function (CDF) is used to model the RMS delay spread based on different distributions. In this paper, the parameters that are derived from 28 GHZ measurements which were conducted in New York City have been used to modify the COST 2100 model. The modified model is used to model the wideband channel at 28 GHz band in LOS scenario. The results show that the RMS delay spread varies between 129 ns and 247 ns for LOS scenario. The results also show that the correlation between RMS delay spread and transmitter-receiver (TX-RX) separation distance is low. The maximum mean excess delay is 454.8 ns.