Urban Radio Access Networks

The increase in demand for high-data rates on the move in the complex urban
environment requires either the allocation of new spectrum such as available
contiguous spectrum in the mm-wave band or the use of novel configurations
such as the application of massive multiple-input multiple-output (MIMO)
technology. To enable the design of efficient wireless networks, an understanding
of the propagation phenomena in the diverse urban environments is
fundamental. In this chapter, we present results of studies related to fourth
generation (4G) and future 5G radio systems both outdoor and outdoor-toindoor.
Classifications include rural and highway, BS to pedestrian users,
vehicular-to-vehicular, vehicular-to-infrastructure, container terminals, vegetation,
and high-speed mobility such as trains. Results for path loss (PL)
and shadow fading are presented from various studies of stochastic and
deterministic channel models based in outdoor, indoor-to-outdoor, hotspots,
vehicular, and train environments. Relay stations and the impact of antenna
placement in vehicles, antenna terminal height, and the presence of pedestrians
are discussed. Results of angular spread and rms delay spread of wideband
channels are presented for the frequency bands below 6 GHz allocated for
4G networks, and preliminary results in the mm-wave band, envisaged for
5G networks, including prediction of the impact of rain. To facilitate the
simulation of radio networks in urban environments the Hannover Scenario
is proposed to give a common simulation environment.