A system and method for controlling call admission in a wireless communications network recursively estimates reverse link load levels as a function of changes in base station receive power and/or the number of mobiles served in the cell/sector. In one implementation, a call admission controller utilizes multiple load level estimating methods, whereby a first method estimates load as a function of changes in base station receive power and changes in the number of served mobiles. The call admission controller uses a second method to recursively update load level estimates as proportionally changing with number of users. The call admission controller may utilize a third estimate method as an accuracy check based on a changes in base station receive power measurements. The call admission controller outputs a call blocking command when load level estimates exceed a threshold to avoid cell/sector overload conditions and network instability.