Abstract: An apparatus and method for paging a user terminal (UT) using a satellite communications system having a gateway and one or more satellites, wherein each satellite produces a plurality of beams and each beam includes a plurality of channels. The method of the present invention includes the step of recalling a location of the UT, wherein the recalled location corresponds to a location of the UT at a time t1. In one embodiment this is accomplished by performing a lookup in a table that includes location information for user terminals at different points in time. The method also includes the step of determining an area, based on the recalled location, within which the UT is assumed to be located at a time t2, where time t2 is later in time than time t1. The next step is to determine a time t3, where t3 is equal to or later in time than time t2, when the following two criteria are satisfied. First a satellite of the one or more satellites has an elevation angle between &thgr;1 and &thgr;2.

Abstract: Radiation by an ancillary terrestrial network, and/or satellite radiotelephones that communicate therewith are monitored and controlled, to reduce and preferably prevent intra-system interference and/or interference with other satellite radiotelephone systems. In particular, a satellite radiotelephone system includes a space-based component that is configured to wirelessly communicate with first radiotelephones in a satellite footprint over a satellite radiotelephone frequency band, and an ancillary terrestrial network that is configured to wirelessly communicate with second radiotelephones in the satellite footprint over at least some of the satellite radiotelephone frequency band, to thereby terrestrially reuse the at least some of the satellite radiotelephone frequency band.

Abstract: Satellite radiotelephone systems include a space-based component that is configured to provide wireless radiotelephone communications in a satellite footprint over a satellite radiotelephone frequency band. The satellite footprint is divided into a plurality of satellite cells, in which satellite radiotelephone frequencies of the satellite radiotelephone frequency band are spatially reused. An ancillary terrestrial network is configured to terrestrially reuse at least one of the ancillary radiotelephone frequencies that is used in a satellite cell in the satellite footprint, outside the cell and in some embodiments separated therefrom by a spatial guardband.

Abstract: A method and apparatus for steering beams modulated from a mobile platform in a manner that reduces overall platform payload processing, and therefore payload weight and power requirements. According to the present invention, a beam steering data calculator (64) generates a table of beam steering data sets (60a, 60b), with each data set corresponding to a specific beam-pointing angle mapped to a corresponding cell on the surface of the earth. A data set that corresponds to a received downlink cell address (22a-22e) is read out from the table and mapped to the downlink address, and an output angle of a modulated vehicle beam (16a-16e) that transmits a data packet to the cell address is corrected to correspond to the beam-pointing angle of the read-out data set.

Abstract: The present invention utilizes a dual polarization reception system (200) that utilizes the energy available in orthogonal polarizations to effectively increase link margin, thereby allowing for adequate signal quality reception in difficult environments. A co-polarized and a cross-polarized signal are separately downconverted and demultiplexed. The signals from each demultiplexed output are then sampled and weighted. The weighted samples for each polarity are combined in soft decision combining/decoding circuitry (255, 360), and this circuitry determines the most likely state of a received symbol's transmitted value.

Abstract: A mobile terminal (6) communicates via a satellite (8), which projects a number of overlapping spot beams (10), with a fixed earth station (2). To determine which spot beam (10) is to be used for communication, the mobile terminal signals in a common signalling channel which is simultaneously received by all, or a subgroup of, the spot beams (10). The satellite (8) retransmits to the fixed earth station (2) in separate channels the signal as received by each of the spot beams (10) which are able to receive the common signalling channel. The relative strengths of the signal as received in the different spot beams (10) are compared at the fixed earth station and a communications channel is assigned to the mobile terminal in one of the spot beams (10), selected according to the comparison of signal strengths.

Abstract: An apparatus, method, and computer program product for assigning communication resources in a beam-hopping cellular communication system. The satellite has a multiple beam antenna that covers a number of cells that is greater than the number of available beams In a preferred embodiment, the method includes the steps of selecting a frequency for each beam, computing a dwell time for each cell based on the traffic estimates for each cell and the number of available beams, and selecting a cell hopping sequence for each beam based on the dwell times and predicted inter-beam interference.

Abstract: A system and method for a simultaneous examination of synchronized forward and reverse link data of a telecommunication network is provided. An RF optimizer system first gathers inputs from both the forward link data as saved by a mobile diagnostic unit (MDU) and the reverse link data as provided by a mobile telephone exchange (MTE), and then merges and synchronizes these two distinct and individual data sets. Various parametric data can be viewed simultaneously from different perspectives (map, grid, graph, message views) with each individual perspective to be synchronized with all others.

Abstract: A method and apparatus are provided for supporting the transmission of communications data in a satellite communications network 10 between user terminals 15-18 and a ground station 14 via a satellite 12. At least one carrier signal is generated in a beam spot and conveys communications data over at least one downlink 22-25 to the user terminals 15-18. The carrier signal is modulated simultaneously with independent communications data streams EDP15 and EDP 18 over modulation channels 802 and 804, respectively, of a multi-dimensional modulator 400. By passing independent data streams over each dimension of an n-dimension modulation technique, different encoding schemes may be assigned to user terminals 15-18 based upon the strength of the signal received by the user terminal 15-18.

Abstract: An information providing method and apparatus for providing information to a moving body via an artificial satellite. Information for selecting a desired information and position information of the moving body is transmitted, from the moving body. Information is provided to the moving body from the artificial satellite depending upon the position information of the moving body and the desired information, on the basis of information from the moving body.

Abstract: A satellite communications system (10) provides for snap to grid variable beam size digital beamforming. The communications system (10) has an antenna configuration (20) for maintaining communications links with satellite networking equipment, and a signal processing system (30) for processing signals resulting from the communications links. The beamforming subsystem (40) forms beams based on the processed signals wherein the beams match predetermined grid information. The beamforming subsystem (40) includes a grid database (50) containing predetermined grid information. A beamforming processor (60) converts the predetermined grid information contained in the grid database (50) antenna coefficients. An antenna management system forms beams based on the antenna coefficients.

Abstract: An improved satellite communications system allows for greater spectral efficiency by requiring just two frequencies for wireless communications between a first ground-based station and a second ground-based station via a satellite. Both the first station and the second station use the first frequency to transmit signals to the satellite; the satellite transponds the signals it receives on the first frequency to the second frequency and transmits the signals to the first and second stations on the second frequency. Use of two frequencies in such a manner results in some own-signal interference. The first station preferably stores its outgoing signals in memory and then subtracts out these stored signals to eliminate the its own-signal interference. The second station may likewise store and subtract out its transmissions, but this is not required.

Abstract: A system and method for adjusting satellite communication signal transmit power for signals transmitted to a localized region within a satellite coverage area utilize real-time information on weather conditions (172) and/or actual path losses (174) within the localized regions to adjust the effective isotropic radiated power (EIRP) of the satellite beams (188) to minimize the total radio frequency (RF) power required for transmission. The transmission system may be realized using a variety of antenna types for transmitting spot beams and/or area coverage beams. Representative antenna implementations include multi-beam antennas having a low-level beamforming network and hybrid matrix amplifier system, phased-array with independent input amplitude control and beamsteering for each beam, and a phased-array feeding a confocal imaging system for single broadcast beam per polarization.

Abstract: A communications system and method for assigning forward link transponder assignments to mobile platforms is provided. The communications system comprises at least one ground station in communication with a plurality of satellites and mobile platforms, wherein the mobile platforms receive assignments to various transponders on the satellites through the ground station based on the desired set of data or services. The communications system requires a return link from the mobile platform to the ground station so that changes in the desired data or services can be confirmed, and accordingly, a default transponder assignment table is incorporated in each mobile platform to establish the return link in the event of receiver equipment failure. The communications system further comprises a set of forward link transponder assignments loaded onto a piece of communications equipment to provide the assignments to a piece of receiver equipment in the event of receiver equipment failure.

Abstract: Uplink transmission and reception techniques for a processing satellite including one or more earth terminals 400 connected to receive ATM data cells. One or more encoders 418 are connected to coordinate four data cells with an error correction code to generate data bursts and to coordinate the data bursts with synchronizing bursts to generate data frames. One or more modulators 420 are connected to modulate the data frames by frequency division multiple access modulation to enable placement of the modulated data frames into a plurality of channels. One or more antennas 406 transmit the modulated data frames to a satellite 100 over 48 beams with various forms of polarization. In satellite 100, a receiving multibeam antenna and feed 106 responds to one or more beams of radiocarrier signals having one or more forms of polarization. One or more demodulators 138 demodulate the radio carrier signals into data frames from various channels including a plurality of channel types.

Abstract: A satellite broadcast system and method, particularly useful for television signals, allows for local as well as nationwide broadcast service by allocating greater satellite resources to the more important local service areas. This is accomplished by broadcasting a non-uniform pattern of local service beams and designing the system to establish different service area priorities through factors such as the individual beam powers, sizes, roll-off characteristics and peak-to-edge power differentials. Frequency reuse is enhanced by permitting a certain degree of cross-beam interference, with lower levels of interference established for the more important service areas.

Abstract: A satellite broadcast system and method, particularly useful for television signals, allows for local as well as nationwide broadcast service by allocating greater satellite resources to the more important local service areas. This is accomplished by broadcasting a non-uniform pattern of local service beams and designing the system to establish different service area priorities through factors such as the individual beam powers, sizes, roll-off characteristics and peak-to-edge power differentials. Frequency reuse is enhanced by permitting a certain degree of cross-beam interference, with lower levels of interference established for the more important service areas.

Abstract: A method for determining whether a gateway will service a user terminal in a satellite communication system comprises the steps of (1) determining whether a position of the user terminal is ambiguous, and (2) if the position is ambiguous, then (a) determining whether a previous registration of a service provider for the user terminal matches a current service provider accessible via the gateway, and (b) if the previous registration matches the current service provider, then accepting the user terminal for service by the gateway. Alternate methods involve determining that the user terminal is at either of two ambiguous positions, and (1) determining whether both of the two ambiguous positions are within a service area of the gateway, (2) determining whether at least one of the two ambiguous positions is within a restricted area for which the gateway does not provide service, or (3) determining a parameter of a beam transmitted from the user terminal to a satellite of the satellite communication system.

Abstract: A satellite broadcast system and method, particularly useful for television signals, allows for local as well as nationwide broadcast service by allocating greater satellite resources to the more important local service areas. This is accomplished by broadcasting a, non-uniform pattern of local service beams and designing the system to establish different service area priorities through factors such as the individual beam powers, sizes, roll-off characteristics and peak-to-edge power differentials. Frequency reuse is enhanced by permitting a certain degree of cross-beam interference, with lower levels of interference established for the more important service areas.

Abstract: A communications satellite method and are provided for controlling a configuration of spot beams produced by a communications satellite. A plurality of spot beams are generated by a communications satellite while maintained at a first orbital position with respect to a first portion of the earth. The plurality of spot beams are configured in a first cell pattern to substantially encompass a first portion of the Earth. The satellite is moved to a second orbital position with respect to a second portion of the earth. Once moved, the satellite is reconfigured such that a second plurality of spot beams form a second pattern 85 to substantially cover the new portion of the earth of interest. A network of switches allows the satellite 10 to be reconfigured for operation from multiple orbital positions. The switching network directs individual feeds to different signal paths having different bandwidth and power capabilities.

Abstract: Disclosed are methods and apparatus to control the actions of a user terminal (UT) located at a remote location, possibly far from a gateway (GW), which has an interface to the Public Switched Telephone Network (PSTN) and/or to the Internet. A computer generated and stored database of an area (referred to as a Confidence Polygon), a volume (referred to as a Confidence Volume), and/or a plane (referred to as a Confidence Surface) is used to establish a geometric shape located on the earth, above the earth or in space, or combinations thereof. In addition, there is assigned to these areas, volumes and/or planes a static or a variable value referred to as a Confidence Limit (CL) that can be compared to a value of an error (E) in a position location of the UT. The error signal can either be generated by the UT or by the GW.

Abstract: A satellite broadcast system and method, particularly useful for television signals, allows for local as well as nationwide broadcast service by allocating greater satellite resources to the more important local service areas. This is accomplished by broadcasting a non-uniform pattern of local service beams and designing the system to establish different service area priorities through factors such as the individual beam powers, sizes, roll-off characteristics and peak-to-edge power differentials. Frequency reuse is enhanced by permitting a certain degree of cross-beam interference, with lower levels of interference established for the more important service areas.

Abstract: Methods are provided for determining and enhancing the service efficiency of mobile communications. To assess communication efficiency in each communication region of interest, a signal-fading record is generated for that region and this record is then analyzed to find availability and energy cost for each of a plurality of power-control parameter sets. The results facilitate the selection of power-control parameter sets that enhance system efficiency in each communication region.

Abstract: Apparatus and method for paging a user terminal (UT) using a satellite communications system having a gateway and one or more satellites, wherein each satellite produces a plurality (n) of beams and each beam includes a plurality of channels. The method of the present invention includes the step of recalling a first location of the UT, wherein the first location corresponds to a location of the UT at a first time t1. In one embodiment, this is accomplished by performing a lookup in a table or database that includes location information for user terminals at different points in time. The method also includes the step of determining a first group (g1) of beams which covers the first location of the UT at a second time t2, where g1<n and time t2 is later in time than time t1. A page is then sent from the gateway to the UT on a channel, such as a paging channel, of at least one beam of the first group of beams. In one embodiment, the page is sent on the paging channel of each of the first group of beams.

Abstract: A system and method for a group of artificial satellites. The artificial satellite is placed into an orbit in which an individual satellite orbits on an elliptical orbit so that at least one of the artificial satellites is always viewable within a pre-defined range of operational elevational angle in a zenith direction from a service area. The group of the artificial satellites are satellites on respective different orbits obtained by combining an inclination angle and an eccentricity squared of the elliptical orbit so that a time period during which one artificial satellite of the group of artificial satellites is viewable from ground is substantially identical to a time period during which another artificial satellite of the group of the artificial satellites is viewable from ground.

Abstract: The present invention is a system and method for reducing the transmission of spurious radiation produced by local oscillators (LOs) in a spacecraft-based phased array antenna. The spurious radiation is reduced by spreading a substantial portion of the radiation outside of the earth disk. The spurious LO leakage radiation is spread by adjusting the phase of the LO signal to a specific value in each elemental path such as shifting the phase of the LO signal in every other elemental path by 180 degrees. The phase shifting of the LO signal can be accomplished by various methods, such as the insertion of a transmission line having a length of &lgr;/2 in the LO signal path prior to entering a mixer in every other elemental path, where &lgr; is the wavelength of the LO signal.

Abstract: A method and apparatus for determining the proper satellite communications service to be provided to a subscriber unit that may be integrated with the geographically defined service areas used in terrestrial cellular communications systems. The pre-existing geographically defined service areas are subdivided into quadrilateral tiles wherein each tile corresponds to a single service area. In addition, the tiles are mapped to a grid having a plurality of regularly spaced grid locations. A lookup table is created that references each grid location to the tiles that overlap the grid locations. The position of the subscriber unit and an approximated region of error within which the subscriber unit is likely to be located are used as input. The approximated region of error is mapped to the grid to identify the grid locations that align with the approximated region of error.

Abstract: In a method of allocating links between a set of areas each equipped with at least one gateway and a set of satellites at successive times, the following steps are iterated each time: a) detecting among all links allocated the previous time, using a constraints propagation algorithm, links which must be interrupted, retaining the other links in the new allocation plan, and b) using an optimization algorithm to allocate the remaining links, conforming to conditions imposed by interference problems. Applications include satellite communications.

Abstract: The invention concerns a telecommunications system in which the Earth is divided into areas (26) within which communications are effected by means of transmit and receive means on a spacecraft, such as a satellite, allocated to communication for a plurality of areas. Areas (2610, 2611, 2612) of a first category (28) are allocated signals having respective polarizations (PD, PG) and carrier frequencies (&Dgr;F1, &Dgr;F2) such that two adjacent areas of the first category are allocated signals having different polarizations or carrier frequencies. Each area of a second category (30) is allocated signals having all the available polarizations and all the available carrier frequencies.

Abstract: In order to establish the communication lines among the movable bodies and/or fixed stations and to configure communication system with a small number of satellites, present method has the steps of determining six orbit-related parameters by using a input conditions including a geographical condition of the service area, a desired service time and the tolerance of an ascending vertical angle within which the satellite can be viewed from the service area, and establishing the satellite communication with one or more satellites, an individual satellite being arranged on the orbits selected and combined among plural elliptical orbits corresponding to the determined six orbit-related parameters on which the satellites stay for a sufficiently long time that they may come successfully into sight in the zenith direction.

Abstract: A mobile satellite system includes a network engineering/systems engineering (NE/SE) system. The NE/SE performs the processes of comparing expected traffic loads with capability and availability of space and ground resources in the mobile satellite system, formulating tactical plans to maximize available resources of the satellite, and producing frequency plans for different geographical regions and defining circuit pools for different groups of users of the METs. The NE/SE also performs the processes of defining contingency plans for failure situations, such as failure in the satellite or a ground-based equipment outage, configuring the mobile satellite system including logical resources and physical components generating logical and physical configurations, the logical and physical configurations designed to expand the mobile satellite system capacity for increases in traffic demand, while also supporting new features and services of the mobile satellite system.

Abstract: A satellite broadcast system and method, particularly useful for television signals, allows for local as well as nationwide broadcast service by allocating greater satellite resources to the more important local service areas. This is accomplished by broadcasting a non-uniform pattern of local service beams and designing the system to establish different service area priorities through factors such as the individual beam powers, sizes, roll-off characteristics and peak-to-edge power differentials. Frequency reuse is enhanced by permitting a certain degree of cross-beam interference, with lower levels of interference established for the more important service areas.

Abstract: A satellite-based communications system operating at high data rates includes a plurality of satellites each having uplink and downlink antennas for transmitting and receiving a plurality of signal utilizing a plurality of spot beams to and from a plurality of coverage areas at a predetermined range of frequencies. The system also includes a plurality of user terminals for transmitting and receiving signals to and from the plurality of communications satellites at the predetermined range of frequencies and at one of the first plurality of data rates. Each of the user terminals having a steerable antenna for tracking relative movement of each of the user terminals with respect to each of the plurality of communications satellites are for tracking movement of each of the plurality of communications satellites in order to maintain communications with the plurality of communications satellite.

Abstract: An apparatus and method, for use in a satellite-based communications network, for minimizing blocking of communication between the network and access terminals resulting from differences in the signal propagation delays for the access terminals due to their different locations within a coverage area serviced by a spot beam generated by a satellite in the network. The apparatus includes a spot beam segregator which segregates a coverage area of the spot beam into at least one coverage zone based on the maximum and minimum propagation delay experienced by access terminals within the coverage area of the spot beam. The apparatus further includes a carrier grouper which groups the carrier into a number of groups corresponding to the number of offset zones, and assigns each carrier group to a respective one of the coverage zones.

Abstract: An elliptical satellite communication system including a constellation of satellites which orbit the earth at a height less than that necessary for geosynchronous orbits but which simulate the characteristics of geosynchronous orbits. The satellites' velocity near the apogee portion of their orbit approximates the rotational velocity of the earth, and during that period appear to hover over the earth. The ground stations on the earth always communicate with a satellite at or near its apogee, and hence that satellite appears to the ground station to hover over the earth. During the times when the satellite is outside the apogee portion, its communication is shut off to prevent any possibility of interfering with geosynchronous satellites and its power supply is used to charge a battery on the satellite. Thus, the power supply of the system can be reduced by an amount equivalent to the percentage of time the satellite is not used.

Abstract: A method for re-selecting control channels in a mobile station reduces the use of resources by limiting an evaluation of candidate control channels to those channels which satisfy certain criteria and are deemed to be eligible control channels. As a consequence, resources are not spent on attempting to re-select a control channel that is not compatible with the mobile station.

Abstract: An earth station receives a return signal via more than one satellite link from a mobile terminal using TDMA. The earth station selects one or more of the satellite links for transmitting a forward signal on the basis of the quality of signal received via each link. The earth section allocates frequency channels to the mobile terminals according to their location on the surface of the earth, so that the propagation time to and from those mobile terminals which share the same frequency channel is approximately the same. The satellite includes an antenna which generates an array of beams which are individually pointed to fixed regions of the earth, until the elevation of the satellite relative to a fixed region falls below a minimum value, in which case the corresponding beam is redirected to a new area, while the other beams remain pointed at the corresponding fixed areas. In this way, beam-to-beam handover is reduced, while maintaining the boresight of the antenna pointing at the nadir.

Abstract: A satellite broadcast system and method, particularly useful for television signals, allows for local as well as nationwide broadcast service by allocating greater satellite resources to the more important local service areas. This is accomplished by broadcasting a non-uniform pattern of local service beams and designing the system to establish different service area priorities through factors such as the individual beam powers, sizes, roll-off characteristics and peak-to-edge power differentials. Frequency reuse is enhanced by permitting a certain degree of cross-beam interference, with lower levels of interference established for the more important service areas.

Abstract: A method for improving the display of the interaction between cells in wireless environment by a computerized site layout system is presented. Each cell has a cell boundary threshold signal level and a hand-off trigger threshold signal level. After the signal strengths of the cells throughout the environment are calculated, the signal strength data is examined to determine for a primary cell and each of its neighbor cells, in turn, a handoff region where the signal strength of said primary cell is at least equal to its cell boundary threshold signal level and the signal strength of the particular neighbor cells is at least equal to its hand-off trigger threshold signal level. The position of the primary and neighbor cells and the identified handoff regions are graphically displayed. Preferably, each cell is assigned a unique display indicium and the handoff regions are displayed using a combination of the indicia for the primary and respective neighbor cell.

Abstract: A telecommunications system and method is disclosed for provisioning assistance Global Position System (GPS) data to a GPS receiver within a mobile terminal. This can be accomplished by having multiple reference GPS receivers located throughout a cellular network, each reference GPS receiver being capable of providing locally valid lists of visible satellites and the associated ephemeris and clock correction information. The location of the Base Transceiver Station (BTS) within the cell that the mobile terminal with a built-in or attached GPS receiver is currently located in can be used as the local position estimate for that mobile terminal. From this local position estimate, the nearest reference GPS receiver can be ascertained and the relevant assistance data can then be sent to the GPS receiver within the mobile terminal through the cellular network to enable the built-in GPS receiver to calculate its position relatively quickly.

Abstract: A method of allocating links between a set of satellites and a set of areas on the ground, the links being determined by a channel, includes the following steps, which are iterated for each channel and for each satellite: constructing an interference graph, and use of the graph by a search algorithm associated with a constraints propagation algorithm to verify the capacities. Applications include satellite communications.

Abstract: An access terminal for initiating spot beam selection in a satellite communication system, in which the access terminal includes a receiver for measuring the received signal strength (RSS) of a multiplicity of radio frequency communication spot beam links. The access terminal is further provided with a microcontroller for comparing the received signal strengths from each of the multiplicity of spot beams to initiate information communication via a communication channel of the satellite communication system. In a described embodiment, the controller of the access terminal compares seven spot beam links to determine whether to initiate information communication with one of the seven spot beams received. Additionally, a memory coupled to the controller of the access terminal is used for storing spot beam identification information including the spot beam links assigned to the access terminal via the satellite communication system.

Abstract: A spacecraft cellular time-division multiple access (TDMA) communication system (10) includes a spacecraft (12) with an antenna (12a) which produces multiple beams (20a, 20b, 20c) in different directions, to form footprints (20af, 20bf, 20cf) at different locations, including the nadir (3) and the horizon (5). User terminals (16a, 16b, 16c) in each footprint (20af, 20bf, 20cf) transmit reverse control signals (312) as bursts in TDMA time slots over uplinks (106, 110, 114), which are routed by the spacecraft to a network control center (NCC 18), to aid in controlling the operation of the system (10). The NCC (18) receives the bursts within receive time slots (310, 314, 316) which have durations which depend upon the origin of the reverse control signals.

Abstract: A method for reducing call dropping rates in a multi-beam communication system. The multi-beam communication system includes a user terminal, a gateway, and a plurality of beam sources, where each beam source projects a plurality of beams, and where a communication link between the user terminal and the gateway is established on one or more beams. The method according to the present invention relies on a messaging protocol between the gateway and the user terminal. Based on messages sent from the user terminal to the gateway, preferably on a preselected periodic basis, the gateway can determine the more desirable beam(s) for transmitting data or information to the user terminal. The messages sent from the user terminal to the gateway contain values representing beam strengths as measured at the user terminal. The gateway uses the user terminal measured beam strengths to select the beams that should be used for transmitting data or information to the user terminal.

Abstract: Methods are provided for determining and enhancing the service efficiency of mobile communications. To assess communication efficiency in each communication region of interest, a signal-fading record is generated for that region and this record is then analyzed to find availability and energy cost for each of a plurality of power-control parameter sets. The results facilitate the selection of power-control parameter sets that enhance system efficiency in each communication region.

Abstract: The mobile telephone system employs a fleet of satellites and a set of gateway ground stations arranged around the globe for handling communications to and from mobile communication units such as mobile telephones. Signals are transmitted between a subscriber unit and the nearest gateway via one or more of the satellites. The gateway is connected to a set of individual service providers such as local telephone systems. The individual service providers may be constrained for various reasons such as contractual or other legal constraints to handle communications only from subscriber units located in certain geographical areas such as within only certain countries or portions of countries. For a mobile communication from a particular subscriber unit, the gateway selects a service provider capable of handling the communication. In one implementation, the selection is based upon the location of the subscriber unit and upon any preferences specified by the subscriber unit.

Abstract: Multiple-mode cellular radiotelephones use a wide bandwidth receiving mode while scanning for signals in a narrow bandwidth receiving mode. Thus, when it is desired to scan the received frequency band to search for the presence of narrowband signals, the wider receiver bandwidth is first selected. When significant signal energy is identified in the wider bandwidth, a further scan using the narrowband mode may then be provided in order to locate the narrow bandwidth channel containing the strongest signal. In another embodiment, the signals that are received in the wider bandwidth mode are digitized to obtain complex signal samples. The complex signal samples are then processed to determine energy in each of a plurality of narrower bandwidths corresponding to channels in the narrower bandwidth cellular radiotelephone standards.

Abstract: A system and method for managing an interaction with a user of a telecommunications network is disclosed. The telecommunications network utilizes data relating to a geometry of the network. The method and system include identifying a plurality of geographic regions and correlating the geometry with plurality of geographic regions. Therefore, data relating to the plurality of geographic regions can be used by the telecommunications network.

Abstract: A satellite-based telecommunication system is provided which communicates with earth-based users located within a predetermined communications area. The communications areas have an associated interference pattern. A satellite antenna is controlled to form an antenna gain pattern distributed across the communications area. The antenna gain pattern represents the gain at any given point within the communications area. The interference pattern corresponds to the amount of interference associated with each point within the communications area. A method and apparatus are provided for controlling the gain defined by a transmitter and/or receiver of a satellite. The transmitter/receiver produces a desired antenna gain pattern. The preferred embodiment includes determining an interference pattern associated with a communications area of interest. Once the interference pattern is identified, a desired antenna gain pattern is then identified.

Abstract: The invention relates to establishing a connection in a satellite system. The base station continuously transmits information to the satellite for establishing a connection. The first terminal receives the reference and control carrier wave retransmitted by the satellite, whereafter the received information is used for selecting at least one frequency available for communication, and the selected frequency will be used for a desired connection with a particular terminal.