There are three types of calls in a wireless cellular network; handover calls which terminate in a different cell than it originated from, inner calls which terminate in the originated cell and total calls which include both handover and inner calls. In our study, using empirical data, we first show that the handover rate of a regular cell is not negligible. Therefore, call arrivals in a cell have to be modeled by considering handover calls. In this paper, we demonstrate that both handover and inner calls can be separately modeled as Poisson distribution which have unity fraction of variance and mean. In addition, total calls' arrivals also obey the Poisson process either for 1 hour or 24 hour intervals.