Broadcast-Multicast Single Frequency Network versus Unicast in Cellular Systems

Video is an important factor of the load in cellular
networks due to the growing popularity of streaming and
linear services. In unicast transmission mode, the same data is
transmitted as many times as the number of receivers demanding
the same video content. Conversely, in broadcast transmissions
using the Single Frequency Network (SFN) technique, a set of
base stations perform synchronized transmission of the same
waveform to a potentially infinite number of users. The objective
of this study is to compare the performance of unicast and
broadcast. More precisely, we determine the minimum number
of users downloading the same data from which a broadcast
transmission is more efficient than multiple unicast transmissions.
In this paper, a model to calculate the Signal-to-Interference-plusNoise Ratio (SINR) in unicast and broadcast modes is presented,
considering Poisson distributed base stations, path loss, fading,
shadowing, trisectored antennas, SFN with a different number
of base stations and beamforming in unicast mode. Results show
that even when an SFN is formed by just 2 base stations and
unicast transmissions are performed using beamforming with 8
antennas per sector, broadcast outperforms unicast when there
are at least 8 users per cell demanding the same content.