Abstract: A hierarchical communication network includes primary, secondary, and tertiary communication systems. The primary system uses orbiting satellites as communication nodes and forms a pattern of cells that may cover the entire earth and that move over the earth. A given spectrum is divided among the cells in accordance with a reuse plan. Any number of secondary, terrestrial-based systems have secondary region areas of coverage that are substantially smaller than the distance to the orbits of the satellites used by the primary system. Secondary systems monitor the primary system to determine which channels of the spectrum are available for use in their secondary regions. Any number of tertiary, terrestrial-based systems reside within a secondary region and have tertiary region areas of coverage that are substantially confined within buildings. Tertiary systems use channels concurrently used by the primary system in the same area where their tertiary regions are located.

Abstract: A transceiver receives channel control commands which communicate predictions of upcoming frequency bands that might be used for communication or which communicate activations of upcoming frequency bands and time units which will be used for communication. The transceiver includes a plurality of synthesizers which can be switched to control the frequencies at which a receiver and transmitter operate. When predictions are received, frequency IDs associated therewith are used in programming new frequencies into non-activated ones of the synthesizers. When each activation is received, a memory structure is programmed to identify one of the synthesizers, to record a frequency for programming into the identified synthesizer, and to record timing data describing when to program the identified synthesizer and when to activate the identified synthesizer. The memory structure is used to control the programming and switching of synthesizers which drive the receiver and the transmitter.

Abstract: A radio telecommunications system includes a number of satellites in low earth orbits. Subscriber units communicate with the satellites. A single subscriber unit communicates with a single satellite using electromagnetic signals so that a measurement processor can obtain Doppler component, propagation duration, and real time measurements of the signals. A location processor converts these measurements into a geographic location with respect to the earth through an iterative process. The location processor determines the accuracy required for each location determination, and performs only the number of iterations needed to meet the accuracy requirements. A service processor determines which qualifications to apply to communication services offered by the system. These qualifications are based on the subscriber unit's location.

Abstract: A controller operates with a cellular communication system that transmits primary communications. The controller recovers a portion of the spectrum assigned to the primary communications for reuse in transmitting secondary communications. The primary communications' cells move in a predictable manner relative to a site at which the controller is located. The controller monitors primary communications to determine the current active cell. The identities of past active cells are saved so that a historical sequence of active cells is available. A map defining the relative orientation of cells is used with the historical sequence information to predict tracks through newly entered active cells. Based on this prediction, a recoverable cell is selected. Communication link parameters of the recoverable cell are used for secondary communications. The identity of the recoverable cell changes in response to changes in the identity of the active cell.

Abstract: A hand-portable position locating radio has a geolocation (e.g. GPS) receiver providing local position and timing information from geolocation means (e.g. GPS or IRIDIUM satellites) and a local transceiver for sending local position and other information to a communication system (e.g., an IRIDIUM or MILSAT satellite). A data processor coupled to the local transceiver and receiver controls operation of the device, including storing local position information and separating signals broadcast by the communication system into those intended or not intended for the device. The radio prepares an emergency access message which it sends to the satellite communication system in a manner to insure rapid detection of the emergency signal and allocation of a clear channel and time slot for further communication.

Abstract: There is described an apparatus and method for decoding signals produced by a communication system employing cascading or concatenation of error control codes that contain, for example, short memory convolution codes. A novel inner decoder and method is described which is a modified Viterbi decoder that generates soft decisions by using a subset of the operations performed by a normal, hard decision, Viterbi decoder. Results of simulation tests show that the performance of the novel decoder provides a bit error rate performance that matches the theoretical bit error rate for the various signal to noise ratios, which performance is better than decoders previously available. Several implementations are described and compared.

Abstract: A radio telecommunications system includes a number of locator satellites in low earth orbits. Locatable subscriber units communicate with the satellites. A single subscriber unit communicates with a single satellite using electromagnetic signals so that a measurement processor can obtain Doppler component, propagation duration, and real time measurements of the signals. A location processor converts these measurements into a two-position location solution. The two-position solution includes an actual position and an image position. The actual position may be detected in some situations by identifying a cell within which communications take place. In other situations, the actual position may be distinguished from the image position by detecting the eastward rotation of the earth. A service processor determines which qualifications to apply to communication services offered by the system. These qualifications are based on the subscriber unit's location.

Abstract: A radio telecommunications/location system includes a number of locator satellites in low earth orbits. The satellites include multibeam antennas. Locatable subscriber units communicate with the satellites. A single subscriber unit communicates with a single satellite using electromagnetic signals so that measurement processors can obtain Doppler component, and propagation duration measurements of the signals. A location processor converts these measurements into a two-position location solution. The two-position solution includes an actual position and an image position. The actual position may be detected in some situations by identifying a cell within which communications take place.

Abstract: A mixer separates IF components IF1, IF2 of the same frequency which are images of different frequency RF signals RF1, RF2 beating with a given LO signal. The LO signal is applied to a FET active power divider and applied to the drains of a pair of balanced FET mixing elements. The FETs for the active power divider are built from the same device structure as the FETs for the mixing elements sharing drain nodes. The RF signals are passed through a quadrature phase shifter and applied to the gates of the FET mixing elements. The mixed signals appear at the drains of FET mixing elements are applied to opposing ports of a second quadrature hybrid at whose output ports the separated IF output signals IF1, IF2 appear.

Abstract: A stepped via is formed in a circuit board. Large holes are punched in a predetermined pattern in two insulating sheets and small holes are punched in the same pattern in another insulating sheet. The holes are dimensioned so that their diameters are larger than the thicknesses of their respective sheets. However, the diameters of the larger holes are less than the combined thickness of all sheets. The sheets are juxtaposed so that the sheet with the smaller holes is between the other sheets and corresponding holes from the respective sheets are aligned. The sheets are pressed together to form an integral substrate. Metallization is applied from one side of the substrate, then metallization is applied to the substrate from the other side.

Abstract: An environment which includes a communications network, user terminals, and an authentication center provides communication services only to legitimate subscribers. The authentication center receives an equipment ID for each terminal, generates a series of sequence numbers and uses a secret key to encrypt the sequence numbers and the equipment ID with a user ID and an error detection code to form an encrypted block. This block is programmed into an authentication module and sent to the subscriber for installation in the subscriber's terminal. The authentication center sends a public key to network authentication nodes. When the subscriber operates the terminal to gain access to the network, a log-on message, which includes the encrypted block and an unencrypted version of the equipment ID, is sent to an authentication node. The node decrypts the encrypted block and evaluates the IDs and sequence number to determine whether to grant access to services.

Abstract: A carrier allows a semiconductor die to be flip-chip mounted to a printed wiring board. Many carriers are formed together in an array. A bottom pad constellation formed on one side of a carrier is compatible with the printed wiring board's layout rules. This pad constellation couples to a top pad constellation on the opposing side of the carrier through stepped vias. Conductive bumps made from an alloy of gold and a metal from the platinum family are formed on bond-pads of the die. The top pad constellation of the carrier is formed primarily from gold. The carrier's bottom pad constellation is formed from the gold/platinum alloy. Carriers and dice may be tested by probing the carrier's pad bottom constellation. After testing, solder bumps are formed on the bottom pad constellation, and the carrier is soldered to the printed wiring board.

Abstract: A method for providing local matching elements for adjusting the characteristic impedance of local transmission line segments to more closely match the input or output impedance of the particular devices to which they couple. The method includes the step of providing a conductive bridge over the active lead of the transmission line, thereby lowering its characteristic impedance. The method can be applied to narrow transmission line segments needed to make contact to small active devices and/or MMIC's and which otherwise exhibit a substantial impedance mismatch with the small elements.

Abstract: A synchronizer operates to achieve initial synchronization with a TDMA acquisition signal exhibiting a potentially large Doppler. The synchronizer collects samples of a baseband signal during a timing window. A fast Fourier transform (FFT) is performed on the samples to generate a set of spectral data. The window is moved to an identical point in a subsequent frame and the FFT repeated until a high-confidence spectral data set is obtained. If the spectral data set indicates energy concentrated around a discrete frequency, then that discrete frequency represents an estimate of the acquisition signal's frequency. The timing window's timing parameters represent a time slot estimate of the acquisition signal. If the spectral data set indicates energy spread more or less uniformly over the spectrum, then no estimates are indicated and a new window is positioned at a different point in subsequent frames.

Abstract: A bridge is provided between a conventional network scheduling tool and a conventional performance measurement tool which automatically ties the two together. The combination is adapted to operate within an organization having numerous resources that are used to accomplish projects. Data required by the performance measurement tool are collected by the network scheduling tool. These data fall into two categories. One category is utilized by both the network scheduling tool and the performance measurement tool, the other category is utilized exclusively by the performance measurement tool. These data are processed by the bridge so that they have the format and properties needed by each tool. The bridge couples data between the tools and keeps the data stored in each tool consistent. In this way duplicate entry of initial data and revisions are avoided.

Abstract: A communication network keeps track of the locations of mobile units which utilize the network. On powering up, the mobile units determine their current locations using signals broadcast, for example, by overhead satellites. They then send data communication messages to the network describing their locations. The network saves the locations and returns data messages that describe borders which surround the mobile units' locations. The mobile units repetitively determine their current locations on a regular schedule. When their current locations are outside of their prescribed borders, they send other location data messages to the network to update the location data being maintained by the network and to receive a definition of a new border.

Abstract: Data packets are delivered through a constellation of nodes to a termination unit. The node where a packet leaves the constellation is a terminal node. Each packet includes a routing code. When a node receives a packet, it examines the routing code to determine if that node might be the packet's terminal node. A table look up operation is performed using the routing code as an index to a routing table. The table identifies a link to use in routing the packet away from the node to a neighbor node. The packet is also examined to verify compatibility between packet type and a selected link. If an incompatibility exists, a substitute link is selected. When a node concludes that it might be a terminal node for a packet, it evaluates a channel identifier to determine if it is currently serving the party to whom the packet is directed.

Abstract: A network of satellites delivers communications through bi-directional communication links between individual ones of the satellites. Each satellite terminates a plurality of links. All satellites are synchronized to recognize a constant duration frame structure. For each link in the network, satellites at both ends of the link simultaneously transmit data communications into their respective ends of the link using the same frequency band. Transmissions into all links supported by a satellite occur simultaneously. The transmissions continue for a duration that is responsive to the distance between the satellites. Transmissions cease for all links supported by a satellite when the communications from the opposing link nodes have nearly propagated the entire distances between the satellites. After ceasing transmissions, each satellite receives the communications previously transmitted from the opposing satellites into the links therebetween.

Abstract: A distributed communication network includes switching offices (SOs), moving-orbit satellites, and subscriber information managers (SIMs). A population of mobile units (MUs) communicates through the network. A MU automatically determines its location and communicates with the network so that this information is kept current at a SO serving the MU and at a home SIM for the MU. The terrestrial nodes of the network have information showing which MUs are logged on at any given time. This knowledge is used to block calls to MUs known to be logged off. Calls are setup through cooperation between SOs. When calls are being setup to MUs, call-originating SOs determine appropriate SIMs and obtains the current location of the MUs from those SIMs. This current location corresponds to a call-destination SO with which the originating SO may cooperate in setting up a call.

Abstract: A carrier allows a semiconductor die to be flip-chip mounted to a printed wiring board. Many carriers are formed together in an array. A bottom pad constellation formed on one side of a carrier is compatible with the printed wiring board's layout rules. This pad constellation couples to a top pad constellation on the opposing side of the carrier through stepped vias. Conductive bumps made from an alloy of gold and a metal from the platinum family are formed on bond-pads of the die. The top pad constellation of the carrier is formed primarily from gold. The carrier's bottom pad constellation is formed from the gold/platinum alloy. Carriers and dice may be tested by probing the carrier's pad bottom constellation. After testing, solder bumps are formed on the bottom pad constellation, and the carrier is soldered to the printed wiring board.