Abstract: A transceiver includes a transmitter and a homodyne receiver, wherein the receiver is used to process both antenna-received and antenna-reflected signals. Thus, during a receive mode, for example, the receiver downconverts antenna-received signals to baseband signals, which are then processed to recover receive signal information. Then, during a transmit mode for example, antenna-reflected transmit signals are fed back to the receiver, which is retuned to the desired transmit frequency, and thus downconverts the reflected transmit signals to baseband signals. These baseband signals are then processed to obtain a characterization of impedance mismatch between the transceiver's transmitter and the associated antenna. An adjustable matching network disposed in the transmit signal path thus may be adjusted based on the characterization to reduce the mismatch.

Abstract: A wireless communications system including at least one base station operative to communicate with terminals on a plurality of carrier frequencies in repetitive time slots defined thereon is operated by assigning an entire time slot or a spreading-code defined subchannel of a time slot to a terminal based on a communications constraint associated with the terminal. The communications constraint may include a performance requirement, such as an information rate or an error rate, and a signal reception condition, such as signal to noise ratio. According to another aspect, a wireless communications system determines a communications constraint associated with a terminal. The system assigns a time slot, a spreading code, a coding rate and a bandwidth to the terminal based on the determined communications constraint.

Abstract: Methods and systems for time synchronizing a receiver to a spread spectrum signal are described. Exemplary embodiments of the present invention provide for at least a two step process in which, at a first step, a number of candidate synchronization frequencies or timings are identified, followed by confirming one of the candidates as a correct synchronization state at a second or final step. According to the present invention, the confirmation step may be performed at the same time as the step of identifying further candidates by processing the same received signal samples in different ways.

Abstract: Multibit symbols from a signal that is received on a communications channel are decoded by combining a matched filtered signal that is derived from input signal samples, and hard decisions that are derived from the input signal samples, in order to obtain soft symbol values. MLSE-PSP processing may be performed on prefiltered input signal samples to obtain the hard decisions. The original, unprefiltered input signal samples also may be match filtered to determine improved soft information, to thereby allow the symbol decisions to be refined over and the above the result provided by MLSE-PSP. The soft symbol values then may be processed to obtain soft bit values for each bit of the multibit symbols. In particular, the soft symbol values may be converted to soft bit values and interleaved to provide soft, coded bit values. Error correction decoding then may be applied to the soft, coded bit values to provided the decoded bits.

Abstract: A mobile communication system comprises a plurality of cells, with each cell including a network of microstations distributed more or less uniformly throughout the cell. A central controller connected to the network of microstations selects a group of microstations in the vicinity of the mobile terminal to transmit information to the mobile terminal. The selected microstations in the active set for a given mobile terminal is continuously updated as the mobile terminal moves through the network of microstations to form a virtual cell that follows the mobile terminal through the network. Transmission conflicts between two mobile terminals is avoided by inhibiting transmissions from an active microstation to at least one of the co-channel mobile terminals when a transmission conflict is detected.

Abstract: A device and method is provided that transmits a monitor report to the current base station concurrently with the transmission of the informational content carrying signals by embedding the monitor report in the informational content carrying signals. The current base station uses the monitor report to initiate transfer of service for the mobile communication device to the base station with the strongest carrier signal strength by sending appropriate signals to the mobile switching center that in turn signals the base station to take over service for the mobile communication device. A wideband digitizing circuit obtains amplified wideband analog signals from the receiver before channel filtering and demodulation, and converts them to complex digital samples.

Abstract: Multi-extension functionality is provided to a group of two or more mobile terminals in a wireless communication network by the provision of a common number associated with the group. The common number and identification of all mobile terminals in the group are stored in a subscriber database. When a call directed to the common number is received, the caller may be prompted to select an option for contacting group members, such as calling a specific group member, the first to answer, or all group members. Mobile terminals in the group are paged accordingly via their individual telephone numbers, and the appropriate call connections established. The call placement action may be predetermined, selected by the caller, or dependent on extrinsic data. Calls placed by group members may have the common number reported in caller-ID in lieu of their individual telephone numbers.

Abstract: Systems and methods for increasing the efficiency of direct current (DC) power to radio frequency (RF) power include a harmonic matching network that inhibits harmonic current flow for a number of harmonic frequencies. The matching network includes a number of sections, where each section generates an impedance that resonates with the output capacitance at a harmonic frequency. Each section of the matching network also creates a high impedance to the amplifier at the respective odd harmonic frequency.

Abstract: A spread spectrum modulated signal generator is disclosed that reduces the storage requirement for storing values representing filter responses of input signal samples in a digital filter by taking advantage of time-reversal symmetry of the responses. Moreover, the disclosed signal generator supports up-ramping and down-ramping for smooth transmission of spread spectrum modulated signals.

Abstract: In a receiver for receiving data samples including a sequence of symbol values transmitted across the channel, a baseband processor including a first hypothesize unit developing first sets of hypothetical symbol values, a second hypothesize unit developing second sets of hypothetical symbol values different from the first sets, a parameter estimator receiving the received data samples and the first and second sets of hypothetical symbol values and developing parameter estimates based thereon, and a sequence estimator receiving the developed parameter estimates, the first sets of hypothetical symbol values and a delayed version of the received data samples and developing a sequence of detected symbol values related to the received data samples.

Abstract: A system for Internet Protocol voice communication comprises using both the Internet and wireless communications systems to communicate between two individuals. The speech is encrypted and encoded prior to transmission with an error indication field appended to the speech bits. Formatting for the Internet leg of the communications occurs according to Internet Protocol. Errors arising during the wireless transmission are addressed by appropriately ordering the encryption, error correction coding, and error detection together with the appended error indication field.

Abstract: A technique for correlating a stream of signal sample values with a predetermined binary code having a plurality of binary code bits is disclosed. The technique is realized by forming precombinations of groups of the signal sample values in the stream, and then temporally ordering the precombinations. Particular ones of the temporally ordered precombinations are selected based upon particular combinations of the plurality of binary code bits. The particular selected ones of the temporally ordered precombinations are then combined to form a correlation.

Abstract: A method and system for the transmission, reception, and processing of 4-level and 8-level signaling symbols is provided. An inventive modulator is provided for modulating 4-level signaling symbols using an 8-level modulator. Further, this inventive modulator is able to produce 4-level modulation when modulating 4-level signaling symbols using an 8-level modulator, where the 4-level modulation represents the 4-level symbol sequence modulated. Further, a constrained/unconstrained demodulator is provided which is able to demodulate both 4-level signaling symbols and 8-level signaling symbols. The inventive demodulator accomplishes this by limiting the number of new symbol hypotheses and path histories to 4 when working with 4-level signaling symbols, and setting the number of new symbol hypotheses and path histories to 8 when working with 8-level signaling symbols.

Abstract: A receiver is disclosed for decoding spread-spectrum coded signals received through a multi-path propagation channel to obtain decided information symbols. The receiver includes a correlator for correlating the numerical signal samples with a despreading code over information symbol periods to obtain complex correlations for different time-alignments, each time-alignment corresponding to a different one of multiple propagation paths. The receiver hypothesizes data symbol sequences, and forms channel estimates for each of the multiple propagation paths as a function of the complex correlations and the hypothesized symbol sequences and selects the most likely of the hypothesized sequences to decode the information symbols.

Abstract: A dual-mode radiotelephone capable of operation in analog or digital modes. According to exemplary embodiments, a digital signal processor receives a speech signal to be transmitted in the digital or analog mode and generates In-phase (I) and Quadrature (Q) modulating signals. The I and Q signals are supplied to a quadrature modulator for generating a digitally modulated signal and are supplied to an analog modulator for generating an analog modulated signal.

Abstract: A method for determining the position of a mobile radio telephone in a satellite communication system is disclosed. First, a mobile radio telephone scans a plurality of paging channels and measures the signal strength of the paging channels. The mobile radio telephone then selects the paging channel with the strongest signal strength and decodes the information broadcasted on the selected channel. The information contained in the paging channel can include frequencies or timeslots of paging channels in surrounding spot beams. The mobile station then measures the signal strength of paging channels in surrounding spot beams and quantizes the measurements to determine a coarse position of the mobile radio telephone.

Abstract: A dual-mode telephone with a satellite communication adapter is disclosed. According to one embodiment of the present invention, a cellular-type handportable phone is equipped with a connector for the attachment of accessories. This connector provide a satellite communications adapter accessory access to the handset's signal processing resources which may operate in an alternative mode to process signals received from the satellite and converted by the adapter into a suitable form for processing. The processing translates the satellite signals into voice or data, and vice-versa.

Abstract: Transmitted signals from plurality of mobile terminals are received at one or more base stations in a Code Division Multiple Access system. The base stations send the received signals to a central processor in the form of complex signal sample streams. The central processor determines the correlations between the spreading codes used by the mobile terminals and combines the interference correlations with channel estimates to form an interference matrix. The central processor uses the interference matrix to process the received signals reduce the interference between signals from different mobile terminals.

Abstract: Transmitting non-polluting dummy pilot signals in a wireless communication network permits estimation of the downlink propagation channels between a number of joint transmitters and a lesser number of receivers. With fewer receivers than transmitters, loop back information from the receivers is not sufficient to determine the downlink propagation channels between the transmitters and receivers. For N transmitters and M receivers, (N-M) dummy pilot symbols are transmitted to facilitate downlink channel estimation. Each dummy pilot signal is transmitted to an imagined or dummy receiver that is virtually located such that its downlink channel coefficient vector is orthogonal to those of the real receivers. Transmit pre-filtering based on estimated propagation channels is applied to the information signals for the real receivers and to the dummy pilot signals. The extent to which the dummy pilot signals interfere at each receiver is an indication of mismatch between estimated and actual propagation channels.

Abstract: A method and apparatus for reducing battery drain in a mobile station of a radio communication system characterizes and stores the radio environment in which it failed to acquire synchronization with the system. The mobile station then enters a low power mode for a predetermined time duration. Upon exiting the low power mode, the mobile station determines if the radio environment has changed by more than a predetermined threshold. If so, the mobile station will re-attempt initial synchronization.