Impact of Correlation between Link Blockages on Macro-Diversity Gains in mmWave Networks

Blocking objects between a transmitter and receiver cause the transition of wireless communication links from line-of-sight (LOS) to non-line-of-sight (NLOS) propagation. This reduces the received power, particularly at higher frequencies such as millimeter wave (mmWave). We consider a form of macro-diversity in a mmWave cellular network in which a mobile user attempts to connect to two base stations (BSs) simultaneously, to increase the probability of having at least one LOS link. We develop a framework for determining the LOS probability when taking into account the correlation between blockages: for example, a single blockage close to the device could block multiple BSs. We also show that the BS density must scale as the square of the blockage density to maintain a given level of LOS probability.