2 GHz Band MIMO Channel Properties in Urban Small Cell Scenario in Crowded Area

The user traffic volume in the cellular network has been growing rapidly. Recent capacity enhancement techniques based on the small-cell architecture are examined for crowded areas such as urban railway stations and environs. Although small-cell propagation environments are characterized by short distances and low antenna heights, the applicability of current MIMO channel models in those environments has not been adequately investigated. In addition, although there are a great number of pedestrians and vehicles in urban areas, the influence of pedestrians on the MIMO channel models remains unclear. In this paper we carried out channel sounding experiments outside a crowded urban railway station in the 2 GHz band assuming the use of LTE-based cellular systems. To elucidate the influence of pedestrians on the channel properties, the measurements were carried out both in the daytime and in the midnight. The measurements result showed that the received power decreased about 4-5 dB in the daytime due to the shadowing by the pedestrians. In addition, the delay spreads decreased and AoAelv and AoDelv spreads increased in the daytime due to the change of propagation environment caused by the pedestrians.