A cluster management module will receive a transmission from a subscriber module and estimate a range for a subscriber module based on the received transmission. A receive power for the transmission will be obtained and a transmit power for the subscriber module will be determined based on the range of the subscriber module and the receive power of the transmission. Network access will be allowed or denied based on the transmit power of the subscriber module. In a second embodiment, an azimuth angle is additionally determined from the received transmission, and an approximate location of the subscriber module is determined. Network access is then allowed or denied based on the transmit power of the subscriber module and additionally based on the location of the subscriber module.