Abstract: A transmitter which includes a quadrature phase shift keying (QPSK) modulator, and a receiver which includes a pilot correlation filter (PCF), a data matching filter (DMF), a timing recovery mechanism, a sampler, and a QPSK demodulator are provided in a wireless communication system. The transmitter transmits a frame of data symbols and pilot symbols to a receiver in a wireless system. The pilot symbols are inserted in the frame at known time intervals. The QPSK modulator modulates the frame of data and pilot symbols. As the receiver receives the frame of data and pilot symbols from the transmitter, the PCF recovers the pilot symbols sent by the transmitter, whereas the timing recovery mechanism tracks the timing of the pilot symbols in the frame. The DMF enhances the multipath response of the frame of data and pilot symbols at the known time intervals of the pilot symbols, and outputs a plurality of enhanced peaks.

Abstract: A technique for efficient implementation of pilot signals on a reverse link in a wireless communication system. An access channel is defined for the reverse link such that within each frame, or epoch, a portion is dedicated to sending only pilot symbols. Another portion of the frame is reserved for sending mostly data symbols; however, within this second portion of the frame, additional pilot symbols are interleaved among the data symbols. The pilot symbol or preamble portion of the access channel frame allows for efficient acquisition of the access signal at the base station, while providing a timing reference for determining the effects of multipath fading. In particular, a pilot correlation filter provides a phase estimate from the pilot symbols in the preamble portion, which is then used to decode the data symbols in the payload portion. An access acquisition portion of the receiver uses the phase estimates provided by the pilot correlation filter to process the output of a data symbol correlation filter.

Abstract: An antenna apparatus for increasing the capacity in a cellular communication system. The antenna operates in conjunction with a mobile subscriber unit and provides a plurality of antenna elements, each coupled to a respective signal control component to provide a weight to the signal transmitted from each element. The weight for each antenna element is adjusted to achieve optimum reception during, for example, an idle mode when a pilot signal is received. The weight values cause the antenna array to create a beam former for signals to be transmitted from the mobile subscriber unit, and a directional receiving array to more optimally detect and receive signals transmitted from the base station. By directionally receiving and transmitting signals, multipath fading and intercell interference are greatly reduced. The weights are adjusted at the transmitting site in accord with signal quality metric information determined at the receiving site.

Abstract: The performance of digital subscriber loops is tested through transmission, reception and analysis of a multi-tone power ratio (MTPR) waveform, containing plural discrete tones having equal spectral spacings and notches periodically distributed among the tones. The noise floor at a missing sub-carrier spectral location is integrated and compared to signal power of an adjacent sub-carrier within the test vector waveform. From these two values, MTPR is determined for various carrier locations, so that maximum theoretical loop payload can be calculated. To generated a figure of merit (FOM) under test, a data modem is placed at each end of the loop. The FOM obtained from MTPR analysis is channel based, not equipment based, and is independent of receiver implementation. Before placing a new customer in service, the MTPR FOMs for a number of loops are compared to bit rate information in a database, which correlates MTPR with a bit rate for a specific modem.

Abstract: The performance of digital subscriber loops is tested through transmission, reception and analysis of a multi-tone power ratio (MTPR) waveform, containing plural discrete tones having equal spectral spacings and notches periodically distributed among the tones. The noise floor at a missing sub-carrier spectral location is integrated and compared to signal power of an adjacent sub-carrier within the test vector waveform. From these two values, MTPR is determined for various carrier locations, so that maximum theoretical loop payload can be calculated. To generated a figure of merit (FOM) under test, a data modem is placed at each end of the loop. The FOM obtained from MTPR analysis is channel based, not equipment based, and is independent of receiver implementation. Before placing a new customer in service, the MTPR FOMs for a number of loops are compared to bit rate information in a database, which correlates MTPR with a bit rate for a specific modem.

Abstract: A two-way communications system that provides ubiquitous wireless data communication services, such as throughout the continental United States, by using a network of only a few, widely distributed radio base station (RBS) sites and the existing paging network infrastructure. The paging network infrastructure is used as an outbound link to request data from the remote field units. The outbound page message indicates a time and frequency at which the RBSs can expect to receive data from the field units. A network hub or message operations center (MOC) coordinates the operation of the paging systems and RBSs from a central location. For example, the MOC determines an available HF frequency and time for a particular field unit to transmit, and then issues the request for data to the field unit using the existing paging network infrastructure. The field units make use of paging receivers, and an HF transmitter to report remote data such as a geoposition or other sensor data when requested to do so.

Abstract: A two-way communications system provides ubiquitous wireless data communication services, such as throughout the continental United States, by using a network of only a few, widely distributed radio base station (RBS) sites and the existing paging network infrastructure. A network hub or mission operation center (MOC) coordinates the operation of the paging systems and RBSs from a central location. The paging network infrastructure is used as an outbound link over which each of the field units is regularly provided with a outbound data message containing information on the available frequencies and time slots the field units can use to transmit inbound data messages to the RBSs. If any of the field units desires to transmit data to MOC, the field unit selects an available frequency from the outbound data message, and transmits its data at the selected available frequency and time.

Abstract: A two-way communications system that provides ubiquitous wireless data communication services, such as throughout the continental United States, by using a network of only a few, widely distributed radio base station (RBS) sites and the existing paging network infrastructure. The paging network infrastructure is used as an outbound link to request data from the remote field units. The outbound page message indicates a time and HF frequency at which the RBSs can expect to receive inbound data from the field units. A network hub or mission operation center (MOC) determines a radio frequency which is expected to be propagating and clear at the time that a particular field unit is to use the frequency as an inbound link. The MOC then issues the request for data to the field unit using an existing inexpensive wireless system such as the paging network infrastructure.

Abstract: Apparatus for removal of flash from small molded plastic and rubber parts, including a specially configured cryogenic shaking vessel and support and drive means for imparting a reciprocating rotational movement thereto. In the preferred embodiment the generally elongated shaker vessel has rounded ends and bottom, and the vessel is oscillated about an axis perpendicular to the longitudinal axis of the vessel, so that a maximum mixing of the product and the deflashing media, which may be sharply pointed objects such as chrome plated tacks, occurs within the shaking vessel.