Joint mobility and co-channel interference characterization at system level for SDMa cellular systems

Even though degraded link condition due to the excessive intra-cell co-channel interference is the major cause of dropping calls in SDMA mobile cellular systems, most of the published system level studies have not considered co-channel interference as a cause of call forced termination. To include the effect of co-channel interference at system level models, "beam overlapping time" has been previously introduced. Beam overlapping time is the period of time in which users sharing the same radio resource degrade the link condition of each other. This time depends on the current co-channel interference conditions which are the result of the real beam pattern and users mobility. Due to the necessity to understand the behavior of this time, some published works have characterized it based on geometrical considerations. However, if only geometrical considerations are contemplated current co-channel interference conditions are ignored. Thus, to fill this void in this paper beam overlapping time is statistically characterized considering real beam patterns as well as realistic users' movement instead of geometrical considerations. Beam overlapping time is statistically characterized via simulation by means of its cumulative distribution function (CDF), mean, variance, and coefficient of variation. Numerical results show that beam overlapping time strongly depends on the antenna array parameters as well as on the users' mobility.