Abstract: A circuit is designed with a measurement circuit (746) coupled to receive an input signal from at least one of a first antenna and a second antenna of a transmitter. The measurement circuit produces an output signal corresponding to a magnitude of the input signal. A control circuit (726) is coupled to receive the output signal, a first reference signal (&eegr;1) and a second reference signal (&eegr;2). The control circuit is arranged to produce a control signal in response to a comparison of the output signal, the first reference signal and the second reference signal.

Abstract: Antenna reception diversity is provided for wireless communications such that a received signal (r) can be produced by combining antenna signals (vi) with their associated fading amplitudes (&agr;i) as estimated by a linear receiver (32). Also, antenna signals (v1i) can be combined with their associated correlation values (&agr;1i) in place of estimated fading amplitudes. Further, inherent characteristics of a non-linear wireless communication receiver can be exploited such that a received signal (r2, r3) can be produced without any additional overhead that would otherwise be needed to provide estimated fading amplitudes.

Abstract: A receiver in a communication system, for combining various significant components of a multipath fading signal and eliminating all other small components, consists of a signal generator, a plurality of delay devices, a plurality of decision feedback equalizers with embedded coherent signal combiners, a controller, a coherent signal combiner, and a decision circuit. The first decision feedback equalizer receives its inputs signals from a delay device and a signal generator, and each of the rest decision feedback equalizer receives its input signals from a corresponding delay device and the signal generator of its previous decision feedback equalizer. The coherent signal combiner, coupled to the output of the summation circuit of the last decision feedback equalizer, combines all the significant component signals together. The decision circuit makes a decision on transmitted symbol from the output signal of the coherent signal combiner.

Abstract: An optimum combiner that reduces the amount of interference imposed upon a first base station by transmissions of other base stations within the same communication system. Two antennas are used to receive transmissions within a receiving station. A rake receiver is coupled to each antenna. By optimally combining the signals that are received by each independent finger of the rake receiver, interference that is correlated between a finger associated with the first antenna and a finger associated with the second antenna can be minimized with respect to the desired signal. Optimum combining requires determination of optimum combining coefficients. A max-ratio combining algorithm may be substituted for the optimal combining algorithm depending upon interference characteristics.

Abstract: An apparatus for implementing true time delay digital beamformers for forming transmit and/or receive beams in array antennas. The apparatus includes a mixed signal application-specific integrated circuit (ASIC), which is comprised of an analog-to-digital converter (A/D) as an input circuit, an internal digital delay circuit, and a digital-to-analog converter (D/A) as an output circuit. The internal digital delay circuit provides true time delays that are selectable based on digital control, whereas the A/D and D/A circuits provide the interface circuits for the analog input and output signals. Formation of receive beams are accomplished by a plurality of mixed signal ASICs, low pass filters and analog combiners, where these components are connected in a configuration to combine a plurality of low pass filtered and time delayed analog signals located at the outputs of a plurality of mixed signal ASICs.

Abstract: A transceiver is disclosed having a zero intermediate frequency to low intermediate frequency receiver and a direct upconversion transmitter. Calibrations may be performed to minimize direct current voltage offset and in-phase and quadrature-phase path mismatch after downconversion. Automatic gain control is performed prior to downconversion and after upconversion to minimize the introduction of mismatch.

Abstract: In a transponder application, at least one transponder and at least one interrogating reader, the reader has at least two receiving units so disposed, for instance at different distances, relatively to the transponder, that signals from the same are received at different levels by the receiving units. By combination, e.g. by subtraction, of the received signals, disturbing signals received at practically the same level are eliminated while the difference of useful transponder signals is available. This substantially improves system performance in transponder applications and allows to increase the operating distance between reader and transponder.

Abstract: Soft estimate normalization for weighted multiantenna high-order modulation data channel together with separate antenna pilot channels using averaging in first time slots of a transmission time interval with corrections for subsequent time slots.

Abstract: A system and method that rejects interference in a direct-sequence spread spectrum communications system. The system and method implement smooth transitions from hop to hop with minimal transient degradation. Adaptive interference suppression is achieved using a suppression filter and an adaptive algorithm that processes the output of the suppression filter and an estimate of the hopping frequency of the interfering signals to switch between interference filter coefficients of the suppression filter. This creates a notch at the carrier frequency of the interfering signals and rejects interference contained in the communication signals. The interference rejection filter hops with the frequency-hopped spread spectrum interfering signals to maintain its interference rejection capability.

Abstract: A radio communication apparatus subjects each signal which is received via a multi-path and demodulated, to a Hadamard transform at each of fingers, by use of an M-ary quadrature coding scheme, obtains correlation values of codes, combines correlation values output from fingers which obtain valid correlation values, and demodulates a received signal based on a maximum correlation value of combined correlation values. The radio communication apparatus includes an operation unit which obtains a difference between a maximum value and a second largest value of the correlation values of a corresponding one of the fingers, and a lock controller which enables and locks the correlation values output from the corresponding one of the fingers when the difference obtained by the operation unit is greater than or equal to a predetermined value.

Abstract: A mobile communications device includes at least two receivers and a memory module. The power consumption of the mobile communications device is controlled by selectively awakening and sleeping the receivers as needed to ensure that the desired quality of reception to check the control channel for messages from an associated base station and to handle incoming communications is maintained. The mobile communications device may operate in single receiver mode or dual receiver diversity mode. In the dual receiver diversity mode, the mobile communications device may switch between one of a number of diversity combining techniques based on the quality of reception.

Abstract: A receiver for use in a wireless communication system includes a voltage controlled oscillator and estimating means for obtaining a frequency estimate to adjust the voltage controlled oscillator, thereby correcting an oscillator frequency error. The estimating means performs a number of block correlations on a received signal with a known midamble reference. The output of the block correlators are conjugately multiplied and summed to produce a low-variance estimate of the phase change between correlators. A number of the largest summed values are located, and the located values that exceed a detection threshold are summed to provide a single complex number whose angle is an estimate of the phase change between the correlators.

Abstract: An adaptive antenna reception apparatus includes a plurality of receiving sections and a combining unit. Each of the plurality of receiving sections is provided for a corresponding one of paths. The receiving section generates a path-corresponding demodulation signal for the corresponding path and for a corresponding one of arrays of antennas from path-corresponding despread signals for the corresponding path and for the corresponding array using adaptive weights for the corresponding array. The combining unit combines the path-corresponding demodulation signals over all the arrays and all the paths to generate a demodulation signal.

Abstract: A decision feedback equalizer and method that implements blind initialization using an antenna array. The equalizer comprises the antenna array which includes two or more antenna elements that form input paths. Two or more feedforward finite impulse response (FIR) filters are respectively coupled to the two or more antenna elements. An attenuator and a switch are coupled in parallel to outputs of all but one feedforward FIR filter. An adder combines the signals output by the feedforward FIR filters. A decision device is coupled to the output of the adder. A decision feedback FIR filter is coupled to the output of the decision device whose output is fed back to the adder and combined with other signals summed thereby. A switch is coupled between the decision device and the decision feedback FIR filter. The equalizer is initialized using a blind adaptation algorithm.

Abstract: A MIMO radio transceiver to support processing of multiple signals for simultaneous transmission via corresponding ones of a plurality of antennas and to support receive processing of multiple signals detected by corresponding ones of the plurality of antennas. The radio transceiver provides, on a single semiconductor integrated circuit, a receiver circuit or path for each of a plurality of antennas and a transmit circuit or path for each of the plurality of antennas. Each receiver circuit downconverts the RF signal detected by its associated antenna to a baseband signal. Similarly, each transmit path upconverts a baseband signal to be transmitted by an assigned antenna.

Abstract: A subscriber platform for broadband communication, according to various aspects of the present invention, includes an antenna, a plurality of transceivers, and a processor. The antenna supports communication via a plurality of directional beams. The plurality of frequency agile transceivers operate simultaneously, each transceiver being coupled to the antenna for communication via a respective directional beam. The processor is coupled to the plurality of transceivers. And, the transceivers are coupled to the antenna to communicate data among the directional beams as directed by the processor, communication including directional diversity and frequency diversity.

Abstract: Techniques to schedule downlink data transmission to a number of terminals in a wireless communication system. In one method, one or more sets of terminals are formed for possible data transmission, with each set including a unique combination of one more terminals and corresponding to a hypothesis to be evaluated. One or more sub-hypotheses may further be formed for each hypothesis, with each sub-hypothesis corresponding to specific assignments of a number of transmit antennas to the one or more terminals in the hypothesis. The performance of each sub-hypothesis is then evaluated, and one of the evaluated sub-hypotheses is selected based on their performance. The terminal(s) in the selected sub-hypothesis are then scheduled for data transmission, and data is thereafter coded, modulated, and transmitted to each scheduled terminal from one or more transmit antennas assigned to the terminal.

Abstract: Interference reduction is achieved within a communication device using a low complexity antenna array. In at least one embodiment, phase and magnitude values associated with an antenna element within a low complexity array are dynamically adjusted during device operation in a manner that enhances a predetermined quality criterion (e.g., SINR).

Abstract: A finger receiver has a data decision unit for deciding whether there is received data or not. If the data decision unit determines that there is received data, then a symbol data selector outputs, to a circuit at a later stage, accumulated and added symbol data at one of complex-inverse diffusing points in a plurality of phases, which is detected as having a maximum accumulated slot power value by a maximum value detector. If the data decision unit determines that there is no received data, then the symbol data selector outputs, to the circuit at the later stage, accumulated and added symbol data at the same point as the accumulated and added symbol data outputted in a preceding slot.

Abstract: A base station and receiver system for use in a base station which achieves enhanced dependability by logically separating the diversity reception paths into different failure paths. In one embodiment, the receiver system includes a first diversity reception path for receiving a first radio signal and a second diversity reception path for receiving a second radio signal. The first and second radio signals may be amplitude and phase shifted versions of the same information signal according to well known principles of diversity reception. At least one demodulator diversity combines the first and second radio signals and demodulates the diversity combined first and second radio signals. Additionally, the first and second diversity paths are logically separated into different failure paths.

Abstract: An apparatus for combining retransmitted data comprises a buffer for storing received data unfavorably received of received data received by a radio receiver and converted to a base band, a combiner for combining the received data stored in the buffer with retransmitted received data, and a demodulator for demodulating the combined data combined by the combiner, wherein the demodulation is performed after combining the received data stored in the buffer with the retransmitted received data.

Abstract: A method forms polar diagrams in a connection between a subscriber and a base station with an antenna arrangement in a radio communications system using multiple access methods. Antenna signals are associated with polar diagrams of the antenna arrangement by a common beam forming network. The common beam forming network is used to form weighted sum signals, which are passed as input signals to a user-specific beam forming unit. A selector which is arranged there takes from the input signals a user-specific subset Kc of signals, to which an eigen polar diagram forming algorithm is applied.

Abstract: The invention relates to a method of transmitting data from a transmitter to a receiver in a radio system, and to a radio system.

Abstract: An optimum combiner that reduces the amount of interference imposed upon a first base station by transmissions of other base stations within the same communication system. Two antennas are used to receive transmissions within a receiving station. A rake receiver is coupled to each antenna. By optimally combining the signals that are received by each independent finger of the rake receiver, interference that is correlated between a finger associated with the first antenna and a finger associated with the second antenna can be minimized with respect to the desired signal. Optimum combining requires determination of optimum combining coefficients. A max-ratio combining algorithm may be substituted for the optimal combining algorithm depending upon interference characteristics.

Abstract: Correspondingly to transmission channel frequency responses calculated at each of a plurality of receiving parts respectively, frequency spectrum signals, which are obtained by transforming frequency of received orthogonal frequency division multiplexing signals, are given weighting, and frequency spectrum signals for each are combined. With these steps, not only estimation of distortion in the amplitude direction and in the phase direction becomes more accurate, but also reproduction of frequency spectrum signals and digital signal sequence becomes more precise so as to realize combined diversity reception.

Abstract: A vehicular audio system receives audio inputs from audio sources and a radio receiver. Analog audio is converted to digital, and digital audio remains natural digital. The receiver front end converts a radio signal to an intermediate frequency then an ADC converts that to a digital signal. The inputs that are converted to digital are selectively mixed with each other and with the natural digital signals. This allows for sounds from multiple sources to be heard simultaneously so that a telephone ring may be provided without requiring background music to be interrupted and for uses such as voice by microphone over a music tape. A reference frequency to the receiver front end of 7.2 MHz is particularly beneficial for noise reduction and consequent mixing of digital audio at 48 KHz, the standard frequency for typical digital audio inputs.

Abstract: A receiver chain (53) for use in a wireless communication system includes a compact, highly correlated, multi-element antenna. The multiple antenna elements (34) and (35) are configured to receive a signal from at least one base station. The highly correlated signals output from the antenna elements (34 and 35) are optimally combined in a controller (55) using a set of weighting factors. The set of weighting factors for each base station signal is determined in response to the spatial signatures of the received signals.

Abstract: An optimum combiner that reduces the amount of interference imposed upon a first base station by transmissions of other base stations within the same communication system. Two antennas are used to receive transmissions within a receiving station. A rake receiver is coupled to each antenna. By optimally combining the signals that are received by each independent finger of the rake receiver, interference that is correlated between a finger associated with the first antenna and a finger associated with the second antenna can be minimized with respect to the desired signal. Optimum combining requires determination of optimum combining coefficients. A max-ratio combining algorithm may be substituted for the optimal combining algorithm depending upon interference characteristics.

Abstract: In the conventional diversity reception, information included in each non-selected signal does not contribute to an improvement in the reliability of communications, and transmitting power has been dissipated to satisfy required communication quality. Owing to the setting of encoding in respective base stations to injection, signals each including the same contents, which are received by a mobile station, are used for increasing the reliability of communications without depending on the number of the signals which were capable of being received by the mobile station, to thereby reduce transmitting power for satisfying required communication quality.

Abstract: A method for sending data from a transmit site to a receive site which includes dividing a transmit data stream having a first bit rate into multiple data streams with each of the multiple data streams having a bit rate which is lower than the first bit rate, transmitting each of the multiple data streams over a plurality of RF channels and recombining the multiple data streams at the receive site to provide a receive data stream having a bit rate equal to the first bit rate.

Abstract: A satellite communications system provides an information channel between remotely located transmitters and receivers. A virtual satellite system provides the same service, but divides the signal either in power or in data content into subchannels such that any particular signal is conducted to the intended receiver via a plurality of traditional satellite channels. The receiving terminal accepts the plurality of signals simultaneously from a possible plurality of satellites, combining the subchannels comprising the virtual channel into the original signal content as if conducted via a single channel. The receiving antenna system receives satellite subchannel signals from a plurality of directions using multiple antennas or a single antenna with multi-direction capability. Prior to signal combining, the receiver necessarily time-synchronizes the plurality of subchannels by introducing time delay in some channels before combining the subsignals into the original composite.

Abstract: A mobile radiocommunication terminal includes a first antenna with a first polarization and a second antenna with a second polarization. The antennas are separate and are both used to receive signals. Signals received by the first and second antennas are combined in polarization diversity. Specifically, for each distinct polarization, a Viterbi decoding means outputs the most probable signals and a probability factor associated with the most probable signals. A digital signal processor includes, for each distinct polarization, weighting means that weight the most probable signals by the associated probability factor, and means for summating the signal outputs from the weighting means.

Abstract: Fast macrodiversity switching (FMS) dynamically switches radio links used for traffic and control channels for a mobile station among a number of base transceiver stations (BTS) without changing the radio resource, that is, using the same frequency and time slot combination (TDMA) or frequency and spreading code combination (CDMA). The traffic channel switching is under control of zone managers. Each BTS includes a zone manager where a host BTS has its zone manager designated as a host zone manager and other BTSs (assistant BTSs) have their zone managers designated as assistant zone managers. The control by the host and assistant zone managers includes switching down-link signals to and up-link signals from mobile stations among base transceiver stations which include broadcast channels (non-switched) and dedicated (switched) channels. Measurements of the wireless signals are made at macrodiverse locations.

Abstract: Base stations have a plurality of antenna devices and a radio communicating zone, respectively. Each base station transmits respective information signals multiplied with a first complex weight from one antenna device and multiplied with a second complex weight from the other antenna device, when the mobile station is within each of the communication zones. The base stations renew the first and the second complex weights based on the direction of the mobile station. One of the base stations determines the initial values of its first and second complex weights based on a direction information of the mobile station obtained when the mobile station was in the zone of the other base station, upon moving from one zone to the other zone.

Abstract: A space diversity antenna system provided with dither circuitry in the signal path to one of the antennas to switch a circuit element in and out of the signal path at a high rate. The circuit element can be an amplitude attenuator or a phase changer. This switching results in the substantial elimination of nulling between the two antennas.

Abstract: A pseudonise (PN) code acquisition scheme employs all elements of a smart antenna array and an adaptive threshold. The basic structure is the combination of a conventional PN correlation searcher, an adaptive beamformer, and an adaptive threshold setting circuit. During each observation interval, the adaptive beamformer adaptively updates the weight vector for the smart antenna elements using the accumulated received signal despread with trial PN code phase error as input, preferably at the chip rate. A spatially correlated signal is then formed by weighting an accumulated value of the signal received by each antenna in the array over the observation period with the corresponding final weight of smart antenna weight vector as calculated by the adaptive beamformer. This spatially correlated signal is then compared to a threshold to determine whether PN code acquisition has occurred.

Abstract: Information represented by a signal generated in a communications medium by a first entity is recovered by receiving the signal from the communications medium at a second entity, determining a mobility characteristic for communications between the first entity and the second entity, and adaptively estimating the information from the received signal based on the determined mobility characteristic. The mobility characteristic may be received from the first entity at the second entity, and the information represented by the received signal may be adaptively estimated based on the received mobility characteristic. According to an embodiment of the invention, the mobility characteristic is a cell type identifier which is communicated from a base station to a mobile terminal, the mobile terminal adaptively estimating information from a signal received from the base station based on the communicated cell type identifier.

Abstract: A remote convenience system (10) includes a portable transmitter unit (14) and a receiver unit (18), and by a method, permits remote control of performance of a function, via a signal (16). Preferably, the system (10) is a remote convenience system for a vehicle (12). The transmitter unit (14) has a microcomputer (90) that provides a message that contains a function request. First and second signals are transmitted from the transmitter unit (14). Each signal is provided by a transmitter portion (70) at a different frequency and conveys the complete message. The receiver unit (18) has a detector (e.g., 190) tuned to receive the signal (16) for both the first and second frequencies, and can discern the complete message provided via both frequencies or either frequency. Thus, if the transmitter unit (14) is in a frequency dependent “dead spot”, communication is not prevented.

Abstract: An apparatus for implementing true time delay digital beamformers for forming transmit and/or receive beams in array antennas. The apparatus includes a mixed signal application-specific integrated circuit (ASIC), which is comprised of an analog-to-digital converter (A/D) as an input circuit, an internal digital delay circuit, and a digital-to-analog converter (D/A) as an output circuit. The internal digital delay circuit provides true time delays that are selectable based on digital control, whereas the A/D and D/A circuits provide the interface circuits for the analog input and output signals. Formation of receive beams are accomplished by a plurality of mixed signal ASICs, low pass filters and analog combiners, where these components are connected in a configuration to combine a plurality of low pass filtered and time delayed analog signals located at the outputs of a plurality of mixed signal ASICs.

Abstract: A method and apparatus for soft decision propagation trades off system bandwidth in return for link margin. When signal quality on an uplink is low, a satellite (20) sends soft decision data, rather than hard decision data, to a gateway (40). When path diversity exists on the uplinks, and multiple satellites (20) receive the uplink, multiple versions of soft decision data are sent to the gateway (40). The gateway combines the soft decision data resulting from multiple uplink paths, thereby increasing the effective uplink signal to noise ratio.

Abstract: A wireless telephony system is described wherein remotely distributed transceivers, each of which has only a single antenna for receiving signals from wireless telephones, and such remote transceivers are located close enough so adjacent transceivers receive signals from the same wireless telephones to provide reverse link antenna diversity to help prevent loss of signal from a wireless telephone.

Abstract: An optimum combiner that reduces the amount of interference imposed upon a first base station by transmissions of other base stations within the same communication system. Two antennas are used to receive transmissions within a receiving station. A rake receiver is coupled to each antenna. By optimally combining the signals that are received by each independent finger of the rake receiver, interference that is correlated between a finger associated with the first antenna and a finger associated with the second antenna can be minimized with respect to the desired signal. Optimum combining requires determination of optimum combining coefficients.

Abstract: A low cost redundancy scheme for the radio frequency front end of a wireless hub that requires a minimum number of down converters and upstream receivers to implement. The redundancy scheme may also be used as a back-up support for any upstream channel that is provided with a greater amount of data than the other upstream channels.

Abstract: A system for enhancing signal reception comprises delay devices coupled to a combiner. The delay devices are adapted to delay respective input signals by corresponding offset delay durations to produce time-staggered delayed signals with respect to one another. The combiner is coupled to the delay devices for combining the delayed signals to form a combined signal. A recorder receives the combined signal for recording the combined signal in the time-domain. The recorder records the combined signal in successive measurement cycles. Each successive measurement cycle contains a time window corresponding to each of the delayed signals. An evaluator evaluates the recorded signal for determining average power, within each time window, over a group of the successive measurement cycles for each of the delayed signals to prepare for determining cross-correlation between pairs of the delayed signals.

Abstract: A method of combining at least two received signals (A, A′) of a telecommunication system is described. A first combining algorithm (B1) is processed for providing a resulting signal (S1). A second combining algorithm (B2) is processed for providing a second resulting signal (S2). One of the two resulting signals (S1 or S2) is selected, wherein the selection is depending on the two resulting signals (S1, S2).

Abstract: The performance of a CDMA receiver employing multiple antennas can be improved, in accordance with the principles of the invention, by directly combining together appropriately weighted signals from the rake receiver fingers that are being supplied by at least two different antennas, i.e., they are in two different receiver modules each of which is what would have been called in the prior art a rake receiver module but without the associated summer, to develop an output with at least as good, and more likely an improved, signal to interference and noise ratio (SINR), as compared to the prior art rake receiver architecture. By doing so the functionality of the beamforming coefficients and the rake multiplier vectors is joined, and it is possible to optimize the rake receiver performance.

Abstract: A wideband receiver automatic frequency control (AFC) system which combines multipath or diverse antenna signals, before the carrier frequency error is determined, is provided herein. Rather than independently calculating the frequency error of each transmission path, frequency error is calculated after the multipath signals are summed together. Thus, only a single frequency detector circuit is required. The resulting automatic frequency control system has the accuracy of a system which combines the independently calculated frequency errors, with fewer steps of computation required. A method for combining multipath signals to calculate an average AFC frequency error is also provided.

Abstract: An optimum combiner that reduces the amount of interference imposed upon a first base station by transmissions of other base stations within the same communication system. Two antennas are used to receive transmissions within a receiving station. A rake receiver is coupled to each antenna. By optimally combining the signals that are received by each independent finger of the rake receiver, interference that is correlated between a finger associated with the first antenna and a finger associated with the second antenna can be minimized with respect to the desired signal. Optimum combining requires determination of optimum combining coefficients.

Abstract: A correlation unit 100 de-spreads reception signal in a reception physical channel and a physical channel for channel estimation with a de-spread timing signal designated by a path control unit 330 and supplies the portions of reception symbols in the de-spread reception signal, corresponding to the pilot symbols and the reception symbols corresponding to the reception physical channel, to weighting coefficient estimation units 120 and a weighting circuit 130, respectively. The weighting coefficient estimation unit 120 carries out channel estimation corresponding to paths for individual finger units 200-1 through 200-8. The weighting circuit 130 multiplies a complex conjugate of the estimated weighting coefficient by the reception signal to produce the multiplication result to a RAKE combiner unit 400.

Abstract: An inexepensive diversity receiver compares the received signal strength signal with a threshold value. When the received signal falls below the threshold value a signal is transmitted through a conductor and a delay circuit to a NAND gate. If the signal is applied to the the two inputs of the NAND gate at the same time, the output of the NAND gate switches a bistable flip-flop which in turn connects or disconnects a second antenna that is 180 degrees in phase from the first antenna between a state in which the signals from the two antenna is combined and a state in which they are not combined and only one antenna applies signals to the receiver.