This paper aims to perform an in depth analysis of handoff calls arrival rate in microcell of GSM networks in order to evaluate the wireless network performance and, in turn, to assist in reducing both of call dropping probability and call blocking probability. The main tool that used in this work to analyze the system is the mathematical Steele and Nofal traffic model. In this model, there are seven various parameters; the arrival rate of originating calls in a cell, the blocking probability of originating calls, the fraction of handoff calls to the current cell from the adjacent cells, the probability of handoff failure, the probability that a new call that is not blocked would require at least one handoff, the probability that a call that has already been handed off successfully would require another handoff, the probability that a new call that is not blocked will require at least one handoff. These parameters are investigated and considered in wide values ranges in order to evaluate their effect on the overall handoff arrival call rate. Through the analytical phases, the seven different parameters show dissimilar degrees of impact on the handoff arrival call rate. Accordingly, it is found that the probability that a new call that is not blocked will require at least one handoff is the most effective factor and then the probability of handoff failure.