Abstract: A dynamic channel management method (100) determines which base station (14, 24, 26) is a least utilized base station for servicing a channel request made by a subscriber unit (40). The least utilized base station is based on what base station (14, 24, 26) is more available to handle the channel request. If the least utilized base station can handle the channel request, it assigns and grants a channel to the subscriber unit (40). Otherwise, the channel request is blocked or denied. The dynamic channel management method (100) provides a systematic way for dynamically matching the available channel resources with the actual demand as a function of time. This enables the system (10) to handle significantly more traffic than with pure static channel management schemes.

Abstract: A dispatch system (10) uses satellites (40) to broadcast simultaneously to an individual remote unit (30), to a select group of remote units (30) or to all the remote units (30). The dispatch system (10) may assign a remote unit (30) to a unique channel if there are enough available channels, or may assign the remote units (30) to a shared channel when the number of available channels is limited. The remote units (30) are given a unique control code or a shared control code. Based on the channel and the control code, the remote unit (30) will be able to listen to the broadcast or ignore it.

Abstract: A communications system (100) has at least one TDD platform pair (130, 200) operating synchronously using a Time Division Duplex (TDD) frame structure. A TDD platform pair (130, 200) has first communications platform (124) and second communications platform (126) that are coupled (135) together. First communications platform (124) transmits first data during a first frame and receives second data during a second frame. Second communications platform (126) receives third data during the first frame and transmits fourth data during the second frame. At least one TDDSU (110) receives the first data, transmits the second data, transmits the third data, and receive the fourth data. First communications platform (124) has a first coverage area, and the second communications platform (126) has a second coverage area. A dual coverage area exists where the first coverage region overlaps the second coverage region. At least one TDDSU (110) is located within the dual coverage region.

Abstract: A communications network is capable of using time division multiple access (TDMA) techniques, code division multiple access (CDMA) techniques, or a combination of both. A subscriber unit (30) makes a request for a traffic channel over a CDMA pilot channel or a TDMA broadcast channel. A satellite (20) or a base station (40) receives the request and determines whether to assign a TDMA or CDMA traffic channel. The downlink and uplink can have the same access scheme (e.g., TDMA) or different access schemes (e.g., TDMA on the uplink and CDMA on the downlink).

Abstract: Advanced subscriber outage notification methods (100) notify a user of a subscriber unit (30) that its call is going to be dropped. The subscriber unit (30), the satellite (20) or the mobile telecommunication system (10) first predicts whether an outage is going to occur and how much time there is before the outage. Second, the subscriber unit (30) notifies the user of the outage and the time remaining before the outage. Third, the subscriber unit (30) waits for whether the user wants to end the call. Next, the subscriber unit (30), the satellite (20) or the mobile telecommunication system (10) terminates the call if the user wants to end the call. Lastly, the mobile telecommunication system (10) drops the call once the time remaining before the outage expires.

Abstract: A communication system (10) has multiple satellites (20) communicating with ground stations (30) and with base stations (40). The satellites (20) are in non-geosynchronous orbit around the earth (52). A first ground station (30) transmits a data packet to a satellite (20). The data packet includes a sector number which represents an area on the earth (52) where the destination ground station (31) is located. The satellite (20) transmits the data packet to another satellite (20) if the satellite (20) is not serving an area identified by the sector number. This step is repeated until the data packet reaches a most likely satellite (20) that is most likely to be serving the area identified by the sector number. The most likely satellite (20) transmits the data packet to the destination ground station (31) if it is still serving the area identified by the sector number.

Abstract: A power amplifier uses a plurality of solid-state amplifiers (FIGS. 2 and 3, 140) arranged in a parallel manner to form a power amplifier module (10). Each solid-state amplifier is adhered to a low thermal expansion insert (130). The insert is then coupled to a low cost aluminum substrate in order to carry the excess heat from each solid-state amplifier (140) to the aluminum housing. The power outputs from the solid-state amplifiers from each module are combined with the power outputs from other modules using electroformed waveguide combiners (FIG. 1, 30, 40).

Abstract: A transmitting unit (10) transmits a video digital signal. The transmitting unit (10) is the delivery system associated with a source that can provide digital video signals, including but not necessarily limited to a satellite television system, a local television station or a cable television provider. A receiving unit (100) receives the broadcasted signal and demultiplexes the signal into a multicasting segment (52) and a baseline video bitstream (54). A portion of the multicasting segment (52) is stored in memory until such time that it is displayed on a television monitor (110). The baseline video bitstream (54) usually comprises a television show which is displayed on the television monitor (110) unless the multicasting segment (52) (e.g., commercial) is being displayed.

Abstract: A high speed packet switch (100) is provided which uses a fabric size of 128.times.128 and operates at a 2.5 Gbps rate. Parallel data transport techniques are used to obtain the 2.5 Gbps data rate while operating internal switches (160) at slower rates. The packet switch fabric is fabricated on a single ASIC using high speed CMOS.

Abstract: In cellular communication systems, hand-offs are performed to maintain links as subscriber units (110) and cells (420, 450) move relative to each other. The hand-off process is improved by using a pre-stored time-based cell map (400) and precise geo-location data. This information is used to set a hand-off timer for deterministically initiating the hand-off process in the current cell (500). The timer diminishes the amount of power monitoring which is required in the hand-off initiation process. This capability is especially important in satellite communication systems with fast moving cells and sharp boundaries.

Abstract: A communication system is established for providing dual-coverage areas using communication satellites, one or more terrestrial stations and one or more dual-coverage subscriber units (DCSU). The communication system determines when and where to establish dual-coverage areas. Dual-coverage areas are provided using separate beams from two or more satellites. The satellites can be located in a variety of orbits around the earth. DCSUs receive signals and process data from at least two satellites at one time. DCSUs can also transmit signals to at least two satellites at one time. Data packets which are missing from one channel are replaced by data packets on another channel. Path delays are compensated for on the transmit side to minimize processing requirements on the receive side.

Abstract: In a mobile communications system (10), system (10) through base station (40) or one or more satellites (20) monitors bandwidth availability and determines acquisition channel resource information. The system (10) broadcasts the acquisition channel resource information to the mobile units (30) via satellite (20). According the acquisition channel resource information, the mobile units (30) are enabled at select time instances to access the acquisition channel, obtain a traffic channel and transmit their messages to base station (40). Thus, mobile units (30) are enabled to access system (10) when resources are available.

Abstract: A packet data communication system (10) where multiple users (87) can access the same channel (22) to maximize an efficiency of the communication system (10). Each channel (22) is divided into time slots. Each time slot is allocated to a user based on the user's request (303) for time slots and the availability of time slots. If time slots are available, then the system (10) will inform the user (87) and allocate the time slot to the user (87, 305). If there are no available time slots, then the system (10) will inform the user (87) that no time slots are available and access to the system's channel is denied. The user (87) will continue to request access (303) to the system (10) as long as the user has data packets to send.

Abstract: A communication network (20) includes a multiplicity of switching nodes (18), many of which are located in orbiting satellites (16). Communication links (30) interconnect the switching nodes (18). A control center (32) performs a request for connection process (40) which routes a new call request over a current internodal topology of links (35) if possible. If the new call request cannot be routed over the current internodal topology of links (35), the process (40) determines how to augment the network with the creation of new links (45) so that the new call can be routed. As calls terminate, unused links are taken out of service.

Abstract: A satellite-based cellular communication system (100) is used to provide emergency services to subscriber units located anywhere on the earth. The surface of the earth is divided into defined areas and emergency codes are assigned to each one of the defined areas. As subscriber units (150) move relative to the surface of the earth, the satellite-based cellular communication system (100) updates the emergency codes stored in the subscriber units (150) as required based on the subscriber unit's current location. The subscriber unit (150) uses the stored emergency codes to determine when a user is requesting emergency services and prioritizes the call accordingly.

Abstract: An on-board aircraft telecommunication exchange (32) provides communication and authentication services for M subscriber identity modules (SIMs) using N transceivers (36), where M can be greater than N. Associations between SIMs (56) and transceivers (36) are established when needed. Accordingly, a pool of transceivers 36 is provided to serve the collective needs of many subscribers. A SIM based authentication process is performed (100) using a subscriber's original SIM (56). That authentication can be extended to a temporary SIM (106) that is substituted for the original SIM throughout the remainder of a flight. Alternatively, the original SIMs (56) may be locked in place and relinquished when a subscriber provides an appropriate PIN.

Abstract: A system facilitates global cellular communication by utilizing a gateway satellite (1000) which communicates with low-earth orbiting satellites (10, 20) via signalling links (1001, 1002). Switching is performed in each of the satellites (10, 20) and switching interconnections as well as voice path communications are switched via the gateway satellite (1000). With switching performed in a gateway satellite (1000), the use of a ground-based gateway network (74) is minimized and, in some cases, eliminated.

Abstract: Classifiers (110) and a selector (112) perform an identification method (300) to identify an ordered set of vectors (e.g., spoken commands, phoneme identification, radio signatures, communication channels, etc.) representing a class as one of a predetermined set of classes. Training processor (104) performs a training method (200) to train a set of models and store the models in a model memory (108). Classifiers (110) receive models from the model memory and combine the models with the ordered set of vectors to determine a set of scores. The selector associates the set of scores with the predetermined set of classes to identify the ordered set of vectors as a class from the predetermined set of classes.

Abstract: An apparatus (10) and method (100) optimize the transmit output power of a power amplifier (14) while providing for controlled backoff independent of temperature, gain stackup or other common error effects. The apparatus (10) and method (100) are particularly relevant to single channel per carrier (SCPC) satellite transmissions, such as a K-band satellite transmissions. The apparatus (10) and method (100) provide the ability to set a maximum drive level of a power amplifier (14) using a feedback loop without overdriving the power amplifier (14) into compression. This approach controls the spectral regrowth that results from running the power amplifier (14) in saturation and limits the AM/PM conversion in the power amplifier (14).

Abstract: A space vehicle uses a signal received from a global positioning system (GPS) satellite (51, FIG. 1) to determine the attitude of a space vehicle. The signal is received through a pair of antennas (10, 11) and converted to sum and difference outputs by a sum and difference circuit (30). These outputs are then conveyed to down converter/correlators (55), and then to envelope detectors (60). The outputs of the envelope detectors (60) are then converted to a digital format by an analog to digital converter (70). The digitally formatted sum and difference amplitudes are then used by a processor (80) to calculate the required attitude adjustment to the space vehicle.