A wireless network system includes a base station of a first network and a user equipment camping on the first network. The base station is configured to set an indicator to a specific value when determining that the first network is not loaded balancedly. The base station then sends the indicator, an update amount, a timer length, and at least one RAN rule including a threshold to the user equipment. The user equipment is configured to start a timer when receiving the at least one RAN rule with the indicator set to the specific value from the base station, adjust the threshold by the update amount when the timer expires according to the timer length, and steer traffic from the first network to a second network or from the second network to the first network when the at least one RAN rule is satisfied according to the adjusted threshold.