A method for changing only one radio channel of an existing duplex radio link is wherein the radio channel changed or to be changed is the disturbed radio channel. The new radio channel (D.sub.n) exhibits, for example in comparison with the disturbed radio channel, only a different timeslot wherein, the radio frequency remains the same.

A jammer for generating and transmitting RF broadband jamming signals for jamming one or more local RF receivers. The jammer includes a broadband antenna unit for receiving broadband RF jammer received signals from local transmitters and for transmission of regenerated broadband RF jamming signals to the local receivers. The jammer uses a plurality of jamming algorithms including a regeneration algorithm and one or more alteration algorithms that alter the regenerated signals whereby the altered regenerated signals are asynchronous with respect to ones of, or all of, the jammer received signals. The alteration algorithms include a chopping algorithm and an FM modulation algorithm.

A cellular mobile communication network in a code division multiple access system includes plural base stations covering cells, respectively, a host base station communicable with the plural base stations and plural mobile stations moved in the cells; when a mobile station becomes uncontrollable, the base station communicating the failure mobile station requests the host base station to register the identity code of the failure mobile station in a list of failure stations, and changes the control channel from an original radio frequency to a new radio frequency without informing the failure mobile station of the new radio frequency so as to disconnect the failure mobile station from the cellular mobile communication network; when another mobile station transmits a request for communication to a base station, the base station inquires the host base station whether the request is acceptable or not, and the host base station checks the list to see whether the identity code of the mobile station has been already registered; thus, the failure mobile station never communicates with the base stations, and does not serve as a serious interference power source.

A system and method of dynamically updating an almanac of base stations with wireless phones that are controlled by end users. First, second, and third location information are received respectfully from a first, second, and third wireless phones. A position of each wireless device is known. The distance between each wireless device an uncooperative base station is determined while accounting for an uncertainty factor. A location of the uncooperative base station is calculated using the first, second, and third location information and the distances. The almanac is updated with the location.