Abstract: A receiver includes a receiver circuit that decodes multiple signals of interest contained in a composite received signal. The receiver comprises a plurality of successive signal detection stages to detect respective signals contained in the composite received signal. Each detection circuit comprises at least one Generalized RAKE combining circuit and generates a detected signal at an output. Each but the last stage further comprises a signal regeneration circuit that cancels the signal of interest detected by that stage from a stage input signal provided to the next stage such that successive detection of the signals of interest benefits from cumulative cancellation of the previously detected signals.

Abstract: An adaptive transmission scheme provides multiple levels of adaptation. At a first level, a selection is made between a limited feedback or open loop scheme and a rich feedback or closed loop scheme. At a second level of adaptation, a diversity mode is selected. Additional levels of adaptation could be employed.

Abstract: A method of supplying channel information in a wireless communication system comprises a mobile terminal normally providing a basic channel report to the wireless communication system; the mobile terminal receiving at least one common feedback criterion broadcast to a plurality of mobile terminals; the mobile terminal determining if the mobile terminal satisfies a condition based on the at least one common feedback criterion; and the mobile terminal selectively providing an enhanced channel report to the wireless communication system based on the determining. The basic channel report may comprise information related to a first set of channel parameters, and the enhanced channel report may provide greater detail on the first set of channel parameters and/or relate to a second set of channel parameters. A method of a base station adaptively controlling channel information reporting by broadcast transmitting at least one common feedback criterion is also presented.

Abstract: A base station schedules one of a plurality of mobile terminals based on an expected SIR of an effective traffic channel associated with a non-scheduled mobile terminal. The expected SIR is generated by computing the expected SIR of a hypothesized traffic channel with a pre-filter adapted to the non-scheduled mobile terminal that would result if the non-scheduled mobile terminal was scheduled. A base station then schedules transmissions to the plurality of mobile terminals based on the computed expected SIR. The expected SIR may be computed so as to compensate for mismatch between the hypothesized traffic channel and a pilot channel associated with the non-scheduled mobile terminal. Alternatively, the expected SIR may be directly computed based on an estimate of the pre-filter of the hypothesized traffic channel.

Abstract: According to the present invention, the effects of the transmission medium on transmitted information symbols are estimated separately from other effects, e.g., those associated with receive and transmit filters, using knowledge of the pulse shaping. The medium response estimate is then used to detect information symbols. Previously, receivers had used estimates of the composite channel to detect symbols. This, however, assumed uncorrelated noise, which is not always the case.

Abstract: A positioning system locates a mobile unit by compensating for component tolerances in time-of-arrivals of received signals at a plurality of positioning radio receivers. The system determines detection times of the received radio signals at the positioning radio receivers. The system takes into account pre-stored signal delays associated with one or more receiver stages of the corresponding positioning radio receivers and the detection times, for determining time-of-arrivals for the received radio signals.

Abstract: A diversity scheme for allowing a transmitter/receiver, such as a mobile unit in a mobile telecommunications system, to exchange communication signals with more than one control station, such as a base station or satellite. According to an exemplary embodiment of the diversity scheme, the mobile unit scans for the control channel of a second satellite during idle time slots while communicating with a first satellite during active time slots. Once the mobile unit detects a control channel from a second satellite, the mobile unit stores synchronization information and establishes a communication link with the second satellite if shadowing or other severe fading causes signal quality over a communication link established with a first satellite to fall below a threshold level. The diversity scheme also allows the mobile unit to communicate simultaneously with two satellites, using alternate TDMA frames.

Abstract: According to the present invention, the effects of the transmission medium on transmitted information symbols are estimated separately from other effects, e.g., those associated with receive and transmit filters, using knowledge of the pulse shaping. The medium response estimate is then used to detect information symbols. Previously, receivers had used estimates of the composite channel to detect symbols. This, however, assumed uncorrelated noise, which is not always the case.

Abstract: Emergency call handling may, in the near future, require terminal unit location information to be provided to emergency service centers. Exemplary embodiments of the present invention provide improved techniques for using a system of monitoring or adjunct stations to provide this location information to the emergency service centers. For example, received signal strength measurements in conjunction with path loss models, alone or in conjunction with either time of arrival (TOA) or time difference of arrival (TDOA) techniques can be selectively used to process received signals and provide location information. Techniques for improving timing estimates are also disclosed.

Abstract: According to the present invention, the effects of the transmission medium on transmitted information symbols are estimated separately from other effects, e.g., those associated with receive and transmit filters, using knowledge of the pulse shaping. The medium response estimate is then used to detect information symbols. Previously, receivers had used estimates of the composite channel to detect symbols. This, however, assumed uncorrelated noise, which is not always the case.

Abstract: A method and apparatus for synchronizing and demodulating radio wave signals transmitted in frame format with an unique word, involving correcting the frequency offset of the received signal and differentially correlating the frequency corrected signal with the unique word, A first timing estimate is further refined by a 2-D search between frequency and time and a first frequency estimate is further refined by quadratic interpolation. The finely synchronized signal is demodulated using a Viterbi-based demodulator.

Abstract: A method and apparatus for channel tracking is disclosed wherein pulse-shaping information is used to improve channel tracking performance. Information symbol values are prefiltered using the pulse shape information for a received baseband signal to generate a filtered waveform. The filtered waveform provides a reference signal for a medium response estimation. The estimated medium response is used with a coherent detector to detect unknown information symbols within the baseband signal. Medium response estimates can be determined for a single detected symbol sequence or for each hypothesized symbol sequence.

Abstract: Emergency call handling may, in the near future, require terminal unit location information to be provided to emergency service centers. Exemplary embodiments of the present invention provide improved techniques for using a system of monitoring or adjunct stations to provide this location information to the emergency service centers. For example, either time of arrival (TOA) or time difference of arrival (TDOA) techniques can be selectively used to process received signals and provide location information. Techniques for improving timing estimates are also disclosed.

Abstract: Exemplary embodiments of the present invention describe terminal position location methods and systems. Relative powers of nearby spot beams which are generated by array antennas are determined. For example, powers from six neighboring spot beams relative to a center spot beam within which a mobile station is currently operating, can be measured relative to the power of the center spot beam. Using information from these measurements, the mobile stations position can be determined using, for example, an exponential model of the spot beam pattern.

Abstract: According to the present invention, the effects of the transmission medium on transmitted information symbols are estimated separately from other effects, e.g., those associated with receive and transmit filters, using knowledge of the pulse shaping. The medium response estimate is then used to detect information symbols. Previously, receivers had used estimates of the composite channel to detect symbols. This, however, assumed uncorrelated noise, which is not always the case.

Abstract: A diversity scheme for allowing a transmitter/receiver, such as a mobile unit in a mobile telecommunications system, to exchange communication signals with more than one control station, such as a base station or satellite. According to an exemplary embodiment of the diversity scheme, the mobile unit scans for the control channel of a second satellite during idle time slots while communicating with a first satellite during active time slots. Once the mobile unit detects a control channel from a second satellite, the mobile unit stores synchronization information and establishes a communication link with the second satellite if shadowing or other severe fading causes signal quality over a communication link established with a first satellite to fall below a threshold level. The diversity scheme also allows the mobile unit to communicate simultaneously with two satellites, using alternate TDMA frames.

Abstract: A reactor for performing reactions at very low, i.e. cryogenic temperatures has a collection vessel mounted above an electron gun to collect vaporized material such as metals, metal oxides, metal salts and metal halides. The collection vessel is maintained at a very low temperature, typically between 14.degree. and 77.degree. K., by a heat pump that also serves as a support for the collection vessel. A manifold introduces a reagent into the reactor between the electron gun and the vessel to react with the vaporized material and form a product. The product is condensed on the collection vessel which may then be inverted to provide a stable support for the collected product during further experimentation.