Abstract: A transmitter of a base station includes a data serial-to-parallel converter, M modulators, M beam formers, and transmission antennas. The data serial-to-parallel converter converts transmission data into M sequences. Each modulator modulates the transmission data. Each beam former weights the modulation signal to form directional beams. The transmission antennas narrow the beams and transmit the modulation signals in parallel (MIMO transmission). In a mobile station, a receiver has reception antennas for receiving data transmitted in parallel and an MIMO demodulator for demodulating the data.

Abstract: A DPRAM is placed in the RF path before the digital to analog converter, to provide dynamic path gain compensation to the digital signal prior to conversion to an analog signal. The DPRAM stores corrections to the signal to compensate for amplitude losses in the signal arising from heat and non-linearities. The DPRAM has two sets of identical addresses. A logic switch, alternately directs an input signal to one of the two sets of addresses. Pre-calculated signal values which compensate for path gain are stored in one of the two sets of addresses in the DPRAM. The signal input to the DPRAM is directed to the other block. The value of the signal input to the DPRAM will determine the address to which the new value can be found. It is this new value which is actually input to the DAC and from which an analog signal is created.

Abstract: An adaptive antenna array (14) includes a muliplicity of antenna elements (12a–12k, 48a–48k) responsive to uplink communications (16a–16k) and arranged to support directional-orientated downlink communication to subscriber units (18). The adaptive antenna array (14) is operationally responsive to a signal processor (28) that co-operates with direction of arrival estimation logic (36) to assess an angle of arrival of uplink communications incident to the array. To avoid inter-cell interference, especially during early stages of a call, the signal processor operates to ensure that a wide area downlink beam (108) is provided for a downlink path to an addressed subscriber unit. With time and/or with reported (68,84) downlink quality of service (QoS) metrics, the signal processor (28) regulates (74, 92, 96) a width of the downlink beam by altering the number of antenna elements used to support the downlink beam, thereby altering the downlink beam aperture.

Abstract: A technique for steering a directional antenna such as may be used in a Wireless Local Area Network (WLAN) device. The technique detects signal parameters during reception of short sync pulses in the very beginning portion of a Packet Protocol Data Unit (PPDU) frame. As a result, the antenna can be steered to an optimum direction for reception prior to receiving other portions of a preamble that may be needed to acquire carrier signal phase and frequency.

Abstract: A mobile communication apparatus having multiple transmission antennas and multiple reception antennas and a mobile communication method used in the mobile communication apparatus, wherein a base station, which has at least one reception antenna, restores long-term and short-term information determined in consideration of first characteristics in a mobile station, which has at least one transmission antenna, from a feedback signal received from the mobile station, spatially processes dedicated physical channel signals using basis information produced from the restored long-term and short-term information, and transmits the results of addition of the spatially-processed signals to pilot signals to the mobile station, wherein the first characteristics are the characteristics of the downlink channels of the respective transmission and reception antennas.

Abstract: A reception weight calculation section 203 calculates reception weights W1 and W2 every antenna using an optimal directional control method in order to improve interference cancellation effect, an arrival direction estimation section 204 estimates a direction of arrive of a received signal for each antenna to calculate steering vectors S1 and S2 for each antenna, and a replica weight calculation section 211 calculates replica weights Wr1 and Wr2 using the reception weights W1, W2 and steering vectors S1, S2.

Abstract: In a diversity CDMA reception apparatus comprising two reception antennas, one of reception levels in two reception antennas is gradually increased during a predetermined time interval while another of the reception levels is gradually decreased during the predetermined time interval. During the predetermined time interval, strength of a received electric field is measured and one of the two reception antennas is selected in accordance with a measured result. In this event, the diversity CDMA reception apparatus is provided with two attenuators corresponding to the two reception antennas to make an attenuating amount of one of the two attenuators gradually decrease and to make an attenuating amount of another of the two attenuators gradually increase.

Abstract: An antenna diversity communications device switches communications paths between a plurality of antennas to improve reception in a frequency diversity communications system. Antenna selection is done in response to measurement of the receiving condition of the selected antenna. A memory unit stores frequency difference information between the current channel and the next channel. When the frequency difference between the current channel and the next channel is small enough to predict good correlation between the channels, and if current receiving conditions are good, the current channel remains connected. When the frequency difference between the current channel and the next channel is large enough to predict poor correlation, or if the receiving conditions on the current channel are bad, one of the other channels is selected.

Abstract: An antenna diversity receiving system is disclosed which includes an antenna device with a plurality of FM antennas and a controllable switching circuit for sequentially switching through one of the plurality of FM antennas via an antenna cable to a receiver upon reception of a switching control signal. The receiver has a multipath detector coupled to a pulse generator for generating a pulse signal to be used as such switching control signal. To secure accurate detection of the switching control signal, the pulse generator is coupled to a pulse shaper to convert the pulse signal of the pulse generator into a pulse signal pair. The pulse signal pair has a first signal pulse followed by a second signal pulse having a signal polarity opposite to the signal polarity of the first signal pulse. The pulse signal pair has a waveform varying symmetrically around a reference level and is supplied through the antenna cable to the antenna device.

Abstract: Disclosed is a method for providing first and second interleaved bit streams to a modulator in order to transmit the first and second interleaved bit streams through at least two antennas in a mobile communication system. An encoder encodes a transmission data stream into a first bit stream with first priority and a second bit stream with second priority being lower than the first priority. An interleaver interleaves the first and second bit streams into the first and second interleaved bit streams. The modulator modulates the first and second interleaved bit streams.

Abstract: A diversity receiver circuit that adaptively selects a variable number of one or more antennas for use in improving signal quality. Each antenna is provided its own receiver that each generates a representation of a received signal. This adaptive selection offers high dynamic adaptability in using the appropriate antennas and receivers at the appropriate time to thereby improving signal-to-noise ratio. The receivers may be direct conversion receivers that implement up-conversion of the baseband signal to reduce DC offset and 1/f noise characteristic of direct conversion architectures.

Abstract: A method of performing receive antenna selection is presented. The method executes a determination operation for a set of receive antennas, determines a maximum result of the determination operation for two of the antennas, eliminates one of the two antennas from the set of antennas, and repeats the determination and elimination process until only a predetermined number of antennas remain in the set. The signals from these remaining antennas are then processed. The present invention reduces receiver complexity and cost.

Abstract: Disclosed are a system and a method for improving performance in an HDR (High Data Rate) wireless terminal utilizing diversity techniques. The wireless terminal comprises two transmission paths, one including a duplexer and the other bypassing the duplexer, and two reception paths, one including the duplexer and the other not including a duplexer and completely isolated from any transmission path. When the terminal is determined to be in an HDR mode, the transmission path including the duplexer and both reception paths are utilized. When the terminal is operating in a low data rate mode, the transmission path bypassing the duplexer and the reception path completely isolated from the transmission paths are utilized, resulting in lower minimum detectable signal, thus reducing current consumption in the wireless terminal.

Abstract: A method provides a technique for optimally combining communication beams. The method forms a plurality of beams from captured signals. One beam is selected as the primary beam while a subset of the others are applied to auxiliary receivers. A digital signal processor weights and combines these primary and secondary beams.

Abstract: It is an object of the present invention to improve the diversity gain by conducting linear prediction of fading fluctuations and switching antennas.

Abstract: An antenna device for transmitting and receiving radio frequency waves, installable in a communication device includes an antenna structure switchable between antenna configuration states. Each state is distinguished by a set of radiation parameters, such as resonance frequency, input impedance, bandwidth, radiation pattern, gain, polarization, and near-field pattern. A switching device selectively switches the structure between the states. The antenna device includes a first receiver which receives a first measured operation parameter indicative of quality of transmission of radio frequency waves by the antenna structure, and a second receiver which receives a second measured operation parameter indicative of quality of reception of radio frequency waves by the structure.

Abstract: Methods and apparatus implementing spatial processing in a remote unit. In general, in one aspect, a remote unit in accordance with the invention includes a plurality of antennas and a spatial processing unit coupled to the plurality of antennas.

Abstract: An antenna switch diversity algorithm, and systems and methods to provide antenna diversity by implementing the algorithm in, for example, an IEEE 802.11a compliant environment, are presented. In accordance with the algorithm, one antenna of at least two antennas is designated as a default antenna at a communications device that sends and receives transmit and receive packets. The default antenna designation is changed depending on long-term and short-term learning processes implemented in, for example, software and hardware. The long-term and short-term learning processes analyze packet transmission and reception results of the antennas. The antenna switch diversity algorithm is applicable to multiple antennas.

Abstract: A method includes monitoring a variable-rate data communication channel to determine its signal-to-noise ratio, and adjusting the data transmission rate of the variable rate data communication channel based on its signal-to-noise ratio.

Abstract: A radio receiver (100) has an IF (intermediate frequency) filter (200) for automatically adjusting its intermediate frequency. The filter (200) includes a filter bank (304), an accumulative sub-band formation (322) and an accumulative sub-band power estimator/switch control (324). The filter bank (304) generates sub-bands, each sub-band having a predetermined frequency range. The accumulative sub-band formation (322) selectively sums the sub-bands to provide lowpass filters having incrementally increasing bandwidth. Power estimates of the lowpass filters are used to determine which lowpass filter output is appropriate for adjacent station interference. Also, if there is no adjacent station interference, the IF filter (200) selects the appropriate filter output depending on the signal strength of the desired station.

Abstract: An antenna device for transmitting and/or receiving electromagnetic radiation, installable in and connectable to a communication device, inlcudes an antenna structure switchable between a plurality of antenna configuration states. Each antenna configuration state is distinguished by a set of radiation parameters, such as resonance frequency, input impedance, bandwidth, radiation pattern, gain, polarization, and near-field pattern. Each of the plurality of antenna configuration states is adapted for use of the antenna device in the communication device in a respective predefined physical operation environment. A switching device selectively switches the antenna structure between the plurality of antenna configuration states.

Abstract: A self-structuring antenna (SSA) system employs a memory device to store switch states for antenna configurations that are determined to produce acceptable antenna characteristics. Each antenna configuration corresponds to a respective combination of switch states known as a switch configuration. Using the stored antenna configurations as a starting point for the process of searching for an antenna configuration that produces acceptable antenna characteristics under particular operating conditions may reduce the search time.

Abstract: An antenna diversity receiver is disclosed. The diversity receiver has a multipath detector for controlling an antenna selective switching circuit. The switching circuit couples one of a plurality of antennas to a RF receiver input. The receiver allows suppression of adjacent channel interferences without unwanted side effects by employing a switching disabling circuit to automatically disabling the switching circuit when the signal delay between the occurrence of multipath distortions in the RF reception signal and the switching between antennas exceeds a predetermined critical signal delay value.

Abstract: An antenna diversity system for receiving frequency-modulated (FM) radio signals with the phase-controlled summation of antenna signals for motor vehicles equipped with a multi-antenna system having at least two antenna output signals, and a receiver with an input for each of a first and a second received signal path, wherein the second of the two received signal paths contains a phase-shifter controlled by a phase-controller. The received signal has the same phase on the output of the phase-shifter as in the first signal path. The two received signals are added up in a phase-coincident manner in a summation circuit, and the added-up signal is supplied to the FM frequency modulator.

Abstract: Describe herein is an apparatus for inclusion in a station of a wireless network, and a method implemented in a station of a wireless network. The method includes wirelessly receiving data via each of a plurality of antennas, the data corresponding to a packet of information transmitted from a remote station, sampling the received data corresponding to the received packet to form data samples for each of the antennas, and determining a measure of signal quality from samples of the received data for each of the antennas. The method further includes selecting one of the plurality of receive antennas as the antenna for receiving from the remote station according to the determined measure of signal quality.

Abstract: Apparatus, and an associated method, for a CDMA communication system. Both closed-loop, power-controlled communication services and best-effort communication services, upon shared channels, are provided in the communication system. A predictor predicts subsequent power level requirements in the system and an allocator allocates power levels at which to communicate best-effort communication signals to effectuate the best-effort communication services.

Abstract: The present invention provides a diversity receiving device with superior interference resistance in a simple construction, comprising a plurality of antennas (11, 12); an antenna switching device (13) that selects any one of a plurality of antennas (11, 12) and carries out connection switching thereof; a demodulator (14) that demodulates a wireless signal and obtains a baseband spread spectrum signal; an A/D converter (15) that A/D converts the baseband spread spectrum signal and generates chip data; a digital matched filter (16) that finds the correlation value of the chip data and the spreading code; a maximum correlation value detection portion (18) that detects the maximum correlation value; an average value calculation portion (21) that finds the average value per frame of the maximum correlation value; and a level comparison device (22) that compares the above-mentioned average value and a predetermined threshold value, and outputs a control signal to the antenna switching device (13) to control antenn

Abstract: A wireless local area network and location system for locating objects within a monitored environment are disclosed. A plurality of access point stations receive and transmit communication signals within a wireless local area network. A processor is operatively connected to each of the access point stations and operative for processing communication signals received from the mobile station and, in one embodiment, determining which communication signals are first-to-arrive signals and conducting differentiation of the first-to-arrive signals to locate a mobile station. Delayed versions of at least one interference signal are weighted and the amplitude and phase controlled with weighted functions W1, W2 . . . Wn. The resultant weighted replicas are summed to determine an approximation of disbursed interference for cancelling interference. The location system can include a tag transmitter and spaced monitoring receivers and processor.

Abstract: An off-board communications system (50) for railway communications to and from a locomotive (10) and a central station (18). A radio (56) utilizes multiple antennas (52, 54) to broadcast a transmission signal (62, 64) over parallel communications paths so to insure that a data sent from a locomotive (10) is complete. In one embodiment, the antennas (52, 54) are selected to broadcast signals as a function of signal magnitude and phase weighting so to optimize transmissions directed at a remotely located receiver (42). In another embodiment, antennas (92, 94) broadcast at different frequencies, and with different modulation and broadcast protocols. A signal divider (74) such as a multiplexer divides the signal prior to transmission, and a signal recombining unit (84) recombines transmitted signals (80, 82) at the receiving site. A performance/availability checker is employed to monitor transmission integrity.

Abstract: A method of selecting between first and second antennas in a quadrature amplitude modulation receiver having in-phase (I) and quadrature (Q) signal channels for demodulating signals received by the antennas, comprising the steps of imultaneously connecting the first antenna to the I channel to obtain a first output signal having a first amplitude, and the second antenna to the Q channel to obtain a second output signal having a second amplitude; measuring the first and second amplitude to obtain a greater amplitude for one on the antennas; and switching to said of the antennas having the greater amplitude for demodulating the received signals.

Abstract: The present invention relate to a wireless communication systems and in particular relates to a wireless diversity scheme. Diversity techniques are well established and known to help in many situations but have generally been considered too complex to implement in a low cost terminal. In accordance with a first aspect of the invention, there is provided a wireless terminal receiver arrangement which has a diverse receiver. Continuous signal assessment and fast switching enables only those signals which contribute to an improvement in the quality of the signal to be switched in.

Abstract: A system adjusts a receiving device in response to sensing symbols. An automatic gain control is adjusted in response receiving a first symbol of a data unit from a first antenna. After adjusting the automatic gain control at least a second and a third symbol of the data unit are received, and in response thereto (1) a first energy of at least one of the second and third symbols is calculated, (2) a first frequency offset of at least one of the second and third symbols is calculated, and (3) a first temporal offset of at least one of the second and third symbols is calculated. The automatic gain control in response receiving a fourth symbol of the data unit from a second antenna is received.

Abstract: A system for selecting an antenna from a diversity of antennas in a DECT, PWT, or TDMA-based telecommunication system. The system combines multiple criteria to improve antenna diversity selections. The principal selection process is based on preamble diversity comparisons that operate in real-time. A preamble diversity switching circuit measures receive signal strength indicators (RSSI) from a plurality of antennas and selects the antenna that provides the highest RSSI value when the difference between the RSSI values exceeds a threshold. When the value of the RSSI difference falls below the threshold, the next selection process, a cyclical redundancy check (CRC) process is employed. The CRC process decodes a CRC value from a signal's content and compares it to a second threshold. If a CRC error is detected and the CRC value exceeds the second threshold, another antenna is selected.

Abstract: A wireless communication system that utilizes a circularly polarized transmitting antenna with dual orthogonal circularly polarized receiving antenna. According to some embodiments, the present invention provides a wireless communication system that includes a first transmitting antenna capable of transmitting first signals having a first type of circular polarization. The transmitting antenna is located at a first location. The system also includes a first receiving antenna capable of receiving second signals having a second type of circular polarization, where the second type of circular polarization is orthogonal to the first type of circular polarization. The system further includes a second receiving antenna capable of receiving third signals having the first type of circular polarization, and the first receiving antenna and the second receiving antenna are both located at a second location.

Abstract: A downlink beamforming apparatus and method. In one embodiment, a method in accordance with the teachings of the present invention includes receiving uplink communication signals from a plurality of antenna array elements, selecting an operating condition of an environment and estimating downlink beamforming weights used in downlink communication signals in response to the selected operation condition of the environment.

Abstract: An adaptive radio receiver utilizes control functions derived from received signals in an interference-limited environment to decide whether to implement conventional single-user demodulation or joint demodulation. The decision to implement joint or conventional demodulation is based upon the values of estimates derived for Doppler spread, carrier-to-interference plus noise, dispersiveness and the likelihood of the presence of a dominant interferer.

Abstract: In a mobile communication system having a plurality of terminals including a diversity terminal, an adaptive array base station controls a down-link transmitting power waveform for a terminal establishing access such that transmitting power is decreased at a timing when a reception level of a chip antenna is measured and that transmitting power is increased at a timing when a reception level of a whip antenna as a transmission antenna is measured. In the diversity terminal, therefore, the whip antenna is more likely to be selected as a receiving antenna, thereby improving down-link reception performance.

Abstract: Estimation of a signal to interference ratio in a cellular communications system is described wherein an estimate for interference is the weighted sum of individual interference estimates along each of a plurality of multi-paths, weighted according to estimates of the signal power, likewise along each of a plurality of multi-paths.

Abstract: The invention relates to the provision of apparatus and a method for the tuning to one of a range of radio frequency signals to receive data which can subsequently be used to generate a radio or television channel selected by the user of the apparatus. The bit error rate of the output of the received radio frequency signal is monitored and, if the bit error rate exceeds the predefined bit error rate limit the apparatus is retuned to a frequency which is equivalent to the selected radio frequency signal plus or minus an offset frequency value. The bit error rate is thereafter monitored and an increase in the offset can be used if required. The invention allows a reduction in data errors which may be caused by interference from other apparatus.

Abstract: An antenna diversity receiver with a variable delay time for antenna switching is disclosed. The antenna diversity receiver includes an antenna selective switching means for coupling one of a plurality of antennas to a RF receiver input. A multipath detector controls the antenna selective switching means. A switching disabling means automatically disables the antenna selective switching means over a disabling period. In order to accurately immunize the receiver the disabling period is controlled by an adjacent channel detector to increase the period with increasing adjacent channel interferences and to decrease the period with descreasing channel interferences.

Abstract: A position location communication system determines the position of a mobile master radio using a round-trip messaging scheme in which the time of arrive (TOA) of ranging signals is accurately determined to yield the range estimates required to calculate the position of the mobile radio. The master radio transmits ranging signals to plural reference radios which respond by transmitting reply ranging signals. Upon reception of the reply ranging signal, the master radio determines the range to the reference radio from the signal propagation time. Any combination of fixed or mobile radios having known positions can be used as the reference radios for another mobile radio in the system. Individual radios do not need to be synchronized to a common time reference, thereby eliminating the need for highly accurate system clocks. Errors in TOA estimates are minimized by performing internal delay calibration, Doppler compensation, leading-edge-of-the-signal curve fitting and frequency diversity techniques.

Abstract: A diversity receiver for receiving digital signals has a soft-decision decoder in each of its receiving sections, to provide confidence values for the received decoded digital values, and combines the values from the receiving sections in dependence upon the confidence values. The receiver is especially suitable for use with COFDM, and has two sections, the outputs of which are applied to a soft-decision combiner which combines the signals in dependence upon confidence values received from the demodulators. The output is then applied to a Viterbi decoder. The combining can simply involve switching but preferably involves averaging. Synchronisation and squelching can be provided. The system can be used with frequency diversity, spatial or polarisation diversity, or with antenna pattern diversity, in which case it can constitute an automatic rotator. The system automatically switches between different types of diversity reception, e.g.

Abstract: A control section comprises receiving energy estimating means for estimating Ec/Io of a receiving signal and switch change control means for changing antennas, in order to implement new control functions. If Ec/Io of the signal received via a selected antenna is lower than a preset level at the incoming or outgoing call time or at the communication time, reception is temporarily executed via the other antenna to detect Ec/Io. After that, the antenna having preferable Ec/Io is employed for the reception.

Abstract: The invention relates to a diversity reception system for motor vehicles for digitally modulated terrestrial and/or satellite radio signals in a frequency range above 1 GHz. The system includes an antenna arrangement which supplies the reception signal to a radio receiver. The antenna arrangement is an antenna system having several individual antennas and several antenna components, and contains a controllable logic switching device. The individual antennas and the several antenna components are positioned on the vehicle so that different reception signals are available at the antenna connection point via discrete switching positions of a controllable logic switch. A reception level testing device comparatively determines the reception level contained in the data flow in the HF-channel with an HF channel bandwidth B.

Abstract: A synchronization system within a dual antenna receiver employs two timing recovery loops each coupled to a different antenna input. Segment sync lock (detection of a segment sync in the data stream) by one timing recovery loop prompts selection of the timing error from the corresponding timing recovery loop for timing recovery within both loops. Both timing recovery loops are then synchronized utilizing the selected timing error. If sync lock for the selected loop is lost, the other loop is selected to provide timing error to both loops.

Abstract: A circuit for changing over between the frequency-modulated HF signals of at least two receiving antennas is described, having a control unit that changes over between the individual antennas as a function of the quality of the antenna output signal. A detector is provided which, when a signal that exceeds the defined reception level is no longer being furnished by any of the antennas, applies to the control unit a signal that effects the changeover to a specific antenna.

Abstract: A method for managing multipath signals to be demodulated by a receiver with multiple demodulators. The method includes a series of steps, including receiving the multipath signals at a wireless communication receiver device, finding the multipath signals having sufficient signal strength for demodulation, and measuring an arrival time of one of the multipath signals. In one embodiment, the present invention also recites measuring a signal-to-noise ratio (SNR) level of one of the multipath signals, updating a multipath list with the arrival time and the signal-to-noise ratio if the multipath signal is identified based upon the arrival time with one of the multipath signals existing in the multipath list, and identifying newly-found multipath signals and evaluating one of the newly-found multipath signals based on the signal-to-noise ratio for categorization into one of a plurality of states.

Abstract: A directivity control of an adaptive antenna is performed for an antenna of a base station when a signal is received in the antenna of the base station, and the directivity control of the adaptive antenna is performed for an antenna of a mobile station when a signal is received in the antenna of the mobile station. Therefore, even though an antenna of a second mobile station functions as an interference wave source, the reception of an interference wave from the interference wave source can be prevented in both the antenna of the base station and the antenna of the mobile station, and a communication quality in both the base station and the mobile station can be maintained in the communication between the base station and the mobile station.

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: A radio communication system includes a base station having a directional antenna for generating a plurality of beams. A first set of the beams is used to receive signals which are decoded at the base station. A second set of the beams is used for interrogating a cell to identify beams which should be added to the first set of beams (for example, in response to mobile terminals entering the cell). In one embodiment, the second set of beams comprises a plurality of searcher beams produced by a fixed-beam phased array antenna. In a second embodiment, the second set of beams comprises a single searcher beam which is scanned through the cell by an adaptive phased array antenna. The radio communication system can be used to communicate with indoor mobile terminals through a plurality of radio heads, and also can be used to communicate with orbiting satellites.