Abstract: A computer-implemented modeling tool for cellular telephone systems predicts signal strength under real conditions within a building, by considering the effects of inter-building and intra-building structures on transmitted signals. The modeling tool gives more accurate predictions under line of sight conditions, when obstructions occur due to inter-building and intra-building structures.

Abstract: A method of preventing roaming fraud in cellular telephone systems using different levels of roaming privileges for individual subscribers. When the subscriber initiates a call in a foreign service area that exceeds their roaming privileges, an authentication method is used to verify the identity of the roaming subscriber.

Abstract: A computer-implemented modeling tool for cellular telephone systems predicts signal strength under real conditions by considering the effects of terrain and man-made structures on transmitted signals. The modeling tool gives more accurate predictions under line of sight conditions, when obstructions occur due to terrain contours, and when mobile or transmitter antennas are blocked by buildings or other structures.

Abstract: A method for reducing roaming fraud in mobile phone systems includes the exchange of an RF signature of a roaming mobile phone between the foreign and home service areas. Thereafter, the analysis of the RF signature can be performed either at the foreign or home service area.

Abstract: A cellular telephone system is described of the type wherein a plurality of contiguous cells, each having an assigned set of identification codes, are arranged with means for maintaining continuous communication with mobile telephones moving from cell to cell. The system allows multiple access by including means for assigning at least one of the in the assigned set of identification codes to more than one mobile telephone. A unique identification code is assigned to a mobile telephone located in the cell. A signal having a unique identification code is generated for identifying the mobile telephone. The signal is coupled to the zones. A combiner is also provided for combining signals from all of the zones in the cell. A receiver is coupled to the combiner for retrieving the signals having the code.

Abstract: The invention describes method and apparatus for reducing intermodulation interference caused by reception of undesired signals in wireless receivers. The apparatus comprises an antenna for receiving the desired signal, a low noise amplifier for amplifying this signal, an adjustable attenuator, and a transmitting antenna to transmit the amplified signal to the wireless receiver. By increasing the strength of the desired signal, the present invention eliminates intermodulation distortion caused by the undesirable signals. The invention also describes an apparatus further comprising an adjustable filter for limiting the spectral content of the transmitted amplified signal, and an apparatus for selecting the characteristics of the adjustable filter in accordance with the measured characteristics of the desired and undesired signals.

Abstract: A mobile radio telephone communication systems provides for rapid system access and registration of mobile phones when the mobile phone operates in an area outside of its home service area. A preferred mobile phone system for a mobile phone is identified before the mobile phone originates a call by determining a location for the mobile phone and selecting the preferred system from a database stored in the mobile phone using the determined location.

Abstract: A method and apparatus for fraud control in cellular telephone systems. The invention identifies relative fraud probabilities for call records from the cellular telephone system, associates the call records with radio frequency (RF) signatures, and identifies the radio frequency signatures as being fraudulent or valid based on the relative fraud probabilities for the associated call records.

Abstract: An integrated radio frequency communication system, known as a Location-Ruled Radio-Integrated Network (LORRAINE) system, provides integrated voice, data and location services. The radio frequency communications system combines time division multiplexing (TDM) techniques with optional time division duplexing (TDD) or frequency division duplexing (FDD) techniques to provide a plurality of time slot channels for these services. Spread spectrum techniques help reduce noise and interference in the system.

Abstract: The present invention discloses a hub and remote cellular system having RF generating equipment located at a centralized hub, and RF front end equipment located at each of a plurality of remote omni-directional cell sites. The centralized hub distributes channels for the remote cell sites. The hub and remote structure provides for the efficient allocation of resources to a plurality of cell sites, lowers equipment costs, real estate costs, regulatory costs, and maintenance costs.

Abstract: A cellular telephone system is described of the type wherein a plurality of contiguous cells, each having an assigned set of identification codes, are arranged with means for maintaining continuous communication with mobile telephones moving from cell to cell. The system allows multiple access by including means for assigning at least one of the in the assigned set of identification codes to more than one mobile telephone. A unique identification code is assigned to a mobile telephone located in the cell. A signal having a unique identification code is generated for identifying the mobile telephone. The signal is coupled to the zones. A combiner is also provided for combining signals from all of the zones in the cell. A receiver is coupled to the combiner for retrieving the signals having the code.

Abstract: A method and apparatus for fraud control in cellular telephone systems. Call records from a switch are scanned to identify a fraudulent cellular phone based on its behavior. An identifier, e.g., a radio frequency (RF) signature, representative of the fraudulent phone is stored in a control channel editor at a cell site. A database of identifiers may comprise a positive validation database storing the identifiers for all valid phones used in the cellular telephone system, or it may be a negative validation database storing the identifiers for known fraudulent phones. A control channel editor intercepts a call origination request transmitted by a phone, and a control processor compares one or more characteristics of the phone transmitting the call origination request to the database of identifiers. The control processor then prevents the call origination request from completing when the comparison indicates that the phone is fraudulent.