In order to lower the capital and operational costs, mobile network operators have started to consider the spectrum resource sharing on the basis of wireless network virtualization. This paper aims to develop the model of spectrum sharing between a primary operator and two other secondary operators; in which they are working together on the basis of distributed dynamic spectrum sharing in a cognitive radio network. The model is then simulated providing the interaction between user's throughput (C), packet arrival rate (A) and the probability of spectrum occupancy (Π) In general, the greater arrival rate is proportional with an increased throughput of both primary and secondary users. However, there are certain critical arrival rate which acts as turning point of another users' throughput. That phenomenon occurs due to the influence of probability of spectrum occupancy. Therefore, it is very important for any mobile operators to maintain network performance, especially the technical parameters related to packet arrival rate and probability of spectrum occupancy.