Abstract: The present invention provides methods, apparatus and systems for delivery of digital data to stationary receivers over a terrestrial wireless link at a low data rate using a new coded orthogonal frequency division multiplexing (COFDM) scheme. Digital data is encoded and modulated using coded orthogonal frequency division multiplexing (COFDM) to produce a data stream. The data stream is communicated to a stationary receiver via a terrestrial wireless link having a ratio of (i) 50% coherence bandwidth to (ii) allocated channel bandwidth of not greater than 50%. The COFDM scheme employed by the present invention overcomes the degradation of multipath fading induced by terrestrial channels, such as the Ultra High Frequency (UHF) broadcast channel.

Abstract: Methods and systems for mitigating a voltage standing wave ratio in a transmitter are disclosed and may comprise calibrating an output power of a power amplifier integrated within a chip using a resistor that models an impedance of an antenna that is externally coupled to the amplifier while the antenna is decoupled. The gain and output power of the amplifier may be determined utilizing the known resistance and a voltage that is measured at an input of the power amplifier, or at a number of points prior to the power amplifier. When the antenna may be coupled to the transmitter, the transmitter output power may then be controlled utilizing the voltage measurements prior to the power amplifier to avoid measuring reflected waves in instances when the antenna impedance may vary. The power amplifier may be of a design that comprises reverse isolation to reduce reflected waves from the antenna.

Abstract: A dual band radio is constructed using a primary and secondary transceiver. The primary transceiver is a complete radio that is operational in a stand alone configuration. The secondary transceiver is a not a complete radio and is configured to re-use components such as fine gain control and fine frequency stepping of the primary transceiver to produce operational frequencies of the secondary transceiver. The primary transceiver acts like an intermediate frequency device for the secondary transceiver. Switches are utilized to divert signals to/from the primary transceiver from/to the secondary transceiver. The switches are also configured to act as gain control devices. Antennas are selected using either wideband or narrowband antenna switches that are configured as a diode bridge having high impedance at operational frequencies on control lines that bias the diodes.

Abstract: Apparatus, and an associated method, for providing transmit diversity to an open-loop MIMO communication scheme, such as a point to multipoint broadcast service in a cellular system. Multiple data streams of the broadcast data are broadcast by way of transmit diversity antennas of a sending station. The data symbols of the separate data streams are phase-shifted to be offset in phase from one another. The data streams, once the data symbols thereof are selectably phase-shifted by a phase shifter, are applied by an applier to sending nodes of the respective cells.

Abstract: Systems and methods that provide channel-adaptive antenna selection in multi-antenna-element communication systems are provided. In one embodiment, a method that selects a subset of receive antennas of a receiver to receive a transmitted RF signal may include, for example, one or more of the following: establishing possible subsets of the receive antennas; determining sets of channel parameter statistics corresponding to the possible subsets of the receive antennas; computing output bit error rates of the receiver, each output bit error rate being computed based on at least one set of channel parameter statistics; selecting a particular possible subset of the receive antennas based upon a criterion predicated on the computed output bit error rates; and connecting one or more RF chains of the receiver to the receive antennas of the selected particular possible subset.

Abstract: In an example embodiment, there is disclosed an apparatus comprising a first transmitter, a second transmitter, and logic coupled to the first transmitter and the second transmitter. The logic is operable to limit a time period the second transmitter is able to transmit while the first transmitter is transmitting.

Abstract: An embodiment of the present invention provides a wireless station (STA) capable of implicit feedback in a wireless local area network, comprising at least one power amplifier, a plurality of antennas capable of being connected with said at least one power amplifier, and a switch capable of switching the connection between said plurality of antennas and said at least one power amplifier thereby enabling said wireless station to sound a complete channel matrix for an access point (AP) in communication with said wireless station (STA).

Abstract: A method and system are provided for improving the isolation characteristics of a combiner. In a system comprising a digital and analog radio signal combiner and a digital transmitter, an analog transmitter, an antenna, and a reject load coupled to the combiner, adjusting an impedance matching device coupled between the reject load and combiner so as to reduce the energy transmitted from the digital transmitter to the analog transmitter through the combiner.

Abstract: A space-time signal processing system with advantageously reduced complexity. The system may take advantage of multiple transmitter antenna elements and/or multiple receiver antenna elements, or multiple polarizations of a single transmitter antenna element and/or single receiver antenna element. The system is not restricted to wireless contexts and may exploit any channel having multiple inputs or multiple outputs and certain other characteristics. Multi-path effects in a transmission medium cause a multiplicative increase in capacity.

Abstract: An integrated circuit (IC) includes a baseband processing module and a radio frequency (RF) section. The baseband processing module is coupled to convert outbound data into amplitude modulation information and phase modulation information when the IC is in a cellular data mode and to convert an outbound radio frequency identification (RFID) signal into RFID amplitude modulation information when the IC is in an RFID mode. The RF section is coupled to generate an outbound RF data signal in accordance with the amplitude modulation information and the phase modulation information when the IC is in the cellular data mode and to generate an outbound RF RFID signal in accordance with the RFID amplitude information when the IC is in the RFID mode.

Abstract: Base stations transmit strip signals using strip signal segments and self supporting modulation scheme techniques facilitating rapid channel estimate. A strip segment occupies one OFDM symbol time interval and uses a set of downlink tones; some, e.g., half, of the tones are left unused facilitating SIR measurement. The strip segments are advantageously timed to correspond to uplink access intervals in which connected wireless terminals do not typically transmit uplink signals. Connected wireless terminals including: multiple antennas used in combination, an antenna duplex module, single RF receiver chain and single RF transmitter chain, switch antenna coefficient combinations based on strip signal segment timing. The wireless terminal determines an independent downlink channel quality measurement, e.g., SNR and/or SIR for each strip signal segment and for on-going non-strip signaling.

Abstract: Transmitter (116) designed to automatically reconfigure one or more circuit parameters associated with an RF power amplifier (210) in response to certain user input commands. Specifically, a transmitter circuit configuration is automatically modified under certain conditions to produce a higher RF output power. The higher RF power output is possible because the transmitter configuration is adjusted specifically for use under a particular set of operating conditions. The operating conditions that trigger the higher powered configuration include burst transmission mode.

Abstract: A method of disrupting communications reception of a target radio receiver. A plurality of transmitters transmit a noise signal toward the target radio transceiver. Each of the plurality of transmitters has a receiver associated therewith A first transmitter ceases transmitting a noise signal at a pre-determined time. A receiver associated with the first transmitter receives information from another of the plurality of transmitters when the first transmitter has ceased transmitting the noise signal. The first transmitter resumes the transmission of the noise signal after the information has been transmitted.

Abstract: An iterative multistage detection system and method for orthogonally multiplexing K channels onto a signal processing chain using N orthogonal sequences of length N. The K channels include a first set of N channels and a second set of M channels (the M channels being separate and distinct from the N channels), where K=N+M. In a first iteration, interference from the first set of N channels imparted on the second set of M channels is removed from the multiplexed signal, thereby enabling the symbol values associated with the second set of M channels to be reliably estimated. In a second iteration, interference from the second set of M channels imparted on the first set of N channels is removed from the first set of N-channels, thereby enabling the symbol values associated with the first set of N channels to be reliably estimated.

Abstract: A method and system optimizes the transmission of a downlink reference signal (DLRS) in a wireless communication system that uses orthogonal division multiple access (OFDMA) for the downlink. Each Node-B (base station) is capable of transmitting the DLRS reference symbols in different subframes of the OFDM radio frame and changing both the number and location of the subframes in response to changing network conditions. The network conditions include the number of terminals being served by the Node-B and multiple access interference (MAI) from adjacent Node-Bs.

Abstract: Frequency pattern generator (1, 101, 201) for generating frequency pulses, said generator having a first local oscillator unit (2-1, 121, 221) for generating a first radio frequency carrier frequency signal (LO1), at least one second local oscillator unit (2-2, . . . 2-N, 122, 222) for generating at least one second radio frequency carrier frequency signal (LO2), a switching device (3, 103, 203) for passing on one of the radio frequency carrier frequency signals (LO1, LO2) or a zero signal (DC) in a manner dependent on a control signal (CTR), and a mixing stage (9, 109, 209, 212, 309) for mixing the signal (LO) that has been passed on by the switching device (3, 103, 203) with a mixing frequency signal (LF) to form a pulsed output signal (RFOUT), the pulsed output signal (RFOUT) having frequency pulses at a respective frequency (f1, . . . f8) and length (Tp) in a manner dependent on the control signal (CTR).

Abstract: There is provided a signal processor with a plurality of antennas connected for transmitting and receiving wireless signals, including a plurality of analog reception processing units, AD converters, DA converters, and analog transmission processing units, wherein each of the analog reception processing units converts the wireless signal received through the antenna into an analog baseband signal and outputs the signal to the AD converter, each of the DA converters converts the digital baseband signal into analog format and outputs the signal, and each of the analog transmission processing units shifts the frequency band of the analog baseband signal output from the DA converter to the high frequency side. The signal processor further includes a transmission switch which switches among the DA converters respectively connected to the analog transmission processing units and a reception switch which switches among the AD converters respectively connected to the analog reception processing units.

Abstract: A multiple frequency antenna array includes a first antenna circuit and a second antenna circuit. The first antenna circuit has a first radiation pattern and is tuned to a first carrier frequency. The first antenna circuit transmits a first representation of a radio frequency (RF) signal at the first carrier frequency, where the first carrier frequency corresponds to a carrier frequency of the RF signal and a first frequency offset. The second antenna circuit has a second radiation pattern and is tuned to a second carrier frequency. The second antenna circuit transmits a second representation of the RF signal at the second carrier frequency, where the second carrier frequency corresponds to the carrier frequency of the RF signal and a second frequency offset.

Abstract: A radio frequency (RF) transceiver integrated circuit (IC) includes a plurality of baseband Tx sections, a plurality of RF Tx sections, a plurality of RF Rx sections, and a plurality of baseband Rx sections. The RF transceiver IC further includes a static digital interface, a dynamic digital interface, and gain control, distribution, and buffering circuitry. Static digital interfaces are operable to receive static gain control commands from a coupled baseband processor. The dynamic digital interface is also operable to receive dynamic gain control commands from the coupled baseband processor. The gain control, distribution, and buffering circuitry is operable to apply the static gain control commands and dynamic gain control commands to at least some of the plurality of baseband Tx sections, the plurality of RF Tx sections, the plurality of RF Rx sections, and the plurality of baseband Rx sections.

Abstract: Provided is a wireless transceiving apparatus for variability of signal processing band, in which at least one resonator of an analog processor and a VCO are simultaneously controlled using a frequency synthesizer, and a frequency of the VCO and a resonance frequency of the analog processor are controlled to have a rational number ratio, thereby capable of varying the signal processing band. The wireless transceiving apparatus includes: an analog processor having a plurality of resonators on a path of transmission/reception signals, for performing analog signal processing; a digital processor for performing digital signal processing on an output signal of the analog processor or data to be transmitted to the analog processor; and a frequency synthesizer for providing a local oscillation (LO) frequency and a controlling signal to the resonators of the analog processor so as to vary a signal processing band of the analog processor.

Abstract: A method for monitoring a redundant (passive) transmitter, being, for example, part of a base station of a point-to-multipoint radio communications system transmits, during normal operation, a spread-spectrum signal over the redundant transmitter, the spread-spectrum signal being of low spectral power in comparison with data signals being transmitted by the active transmitter of the base station. One or more receivers are associated, for example, with terminal stations in communication with the base station and detect the presence of the spread-spectrum signal. If the spread-spectrum signal is not found to be present, the receivers provide an indication of this, and from this indication, a decision is made as to the integrity of the redundant transmitter.

Abstract: A channel estimation method in a Multiple Input Multiple Output (MIMO) mobile communication system having a plurality of transmission antennas and a plurality of reception antennas is provided. In a method of transmitting, by a transmitter, channel estimation signals for channel estimation at a receiver, the transmission antennas transmit the same channel estimation signals for a first frame transmission duration, and transmit predetermined channel estimation signals corresponding to the number of the transmission antennas for a second frame transmission duration.

Abstract: System, apparatus and method are provided for transmitting and receiving packets over first and second channels. An FEC encoder generates forward error correction (FEC) packets corresponding to an original stream of packets. A packet transmitter transmits the original stream of packets over the first channel and transmits the FEC packets over the second channel. A packet receiver receives a stream of packets over the first channel, and receives the FEC packets corresponding to the stream of packets over the second channel. An FEC decoder uses information stored in the FEC packets to determine a correspondence between the FEC packets and the stream of packets, and recovers one or more lost packets of the stream of packets using the FEC packets.

Abstract: Systems and methodologies are described that facilitate monitoring transmitter performance in a wireless communication environment. A metric or metrics associated with one or more pilot symbols can be generated and used to evaluate performance. To generate pilot metrics, a signal analyzer can be used to sample the output of a transmitter and the sampled signal can be propagated to a processor. The processor can generate frequency domain channel estimates for subcarriers. Average channel estimates for the subcarriers can be used with the known pilot symbols to determine noise or error for each subcarrier, which can be used to generate the noise variance for each of the pilot symbols. A pilot modulation error metric can be generated based upon the average channel estimates and noise variance.

Abstract: In a method for selecting a transmission target terminal in a zero-forcing beamforming algorithm, information about a channel capacity of each terminal is received from all K terminals. A terminal with a largest channel capacity is selected as an initial transmission target terminal. A determination is made as to whether the number of currently selected terminals, i, is equal to the predefined number N. If the number of currently selected terminals, i, is different from the predefined number N, information about channel capacities of remaining terminals except previously selected transmission target terminals is received until i is equal to N and a terminal with a largest channel capacity is selected as a transmission target terminal.

Abstract: A radio base station node (20) of a telecommunications network comprises a baseband transmitter (22) and plural radio frequency (RF) paths (24) between the baseband transmitter (22) and an antenna system (30). A measurement entity (32) is provided, preferably near the antenna system (30), for making a measurement or comparison of a time of detecting of a power modulation for each of plural RF transmission paths (24), e.g., a time of detecting of a power modulation for a first of the plural RF transmission paths and a time of detection of a power modulation for a second of the plural RF transmission paths. A transmission timing adjustment unit (34) uses the power modulation measurement or comparison for adjusting timing of transmission of signals for the plural RF transmission paths for obtaining a desired time alignment for the plural RF transmission paths.

Abstract: Apparatus, and an associated method, for facilitating communication of communication data upon a communication channel susceptible to distortion. Both diversity techniques and spatial multiplexing techniques are utilized to compensate for the distortion introduced upon the data during its communication. Separate parts of the communication data are mapped pursuant to separate mapping schemes. The mapping schemes are selected to exhibit different properties. When the communication data is communicated upon the communication channel and delivered to a receiving station, a decoder decodes the data to recover the informational content of the data.

Abstract: A processing unit receives the input of image data sequentially. A specifying unit specifies a synchronization period for the sequentially inputted image data. A measurement unit measures the characteristics of a radio channel over the specified synchronization period. The processing unit stores the measured characteristics of a radio channel in radio packets and transmits the radio packets storing the measured characteristics to other radio apparatuses, and also stores the sequentially inputted image data in the radio packets and transmits the radio packets storing the image data to the other radio apparatuses.

Abstract: The present invention relates to a method for transmitting data between a transmitter provided with at least two transmitting antennas (ta1, ta2 . . . taNt) and a receiver. The method according to the invention further includes a symbol spreading step in the course of which components Zij (for i=I to S and j=I to Nt) of a predetermined number of successive symbols ZI . . . ZS are to be spread over time before being transmitted over said transmitting antennas (ta1, ta2 . . . taNt). The data transmitted at any given moment will thus not be representative of a single symbol Zi (for i=1 to S), as is the case in known MIMO systems, but will represent a mixture between Nt components of S successive symbols, which introduces data diversity with respect to time as perceived at the receiver end.

Abstract: In a transmission power amplifier apparatus, a signal calculator divides an input signal into a plurality of N constant amplitude signals having a substantially identical predetermined constant amplitude value and having predetermined phases different from each other, and N power amplifiers amplify electric powers of the N constant amplitude signals under same predetermined operating condition. A power combiner combines the electric powers of the N power-amplified constant amplitude signals, and outputs a combined output signal. A controller controls the signal calculator to detect an amplitude value of the input signal, to detect an average value and one of a maximum value of the amplitude value of the input signal and a peak-to-peak value of the amplitude value for a unit time interval based on the detected amplitude value of the input signal, and to divide the input signal into the N constant amplitude signals having a constant amplitude value and different phases.

Abstract: An arrangement and method for channel mapping in a UTRA TDD HSDPA wireless communication system by applying interleaving functions in first (530) and second (540) interleaving means to a bit sequence to produce symbols for mapping to physical channels, the first and second interleaving means being arranged to map symbols from respectively systematic and parity bits in a predetermined scheme, e.g., mapping symbols in a forward direction when a channel has an even index number, and in a reverse direction when a channel has an odd index number. The symbols may comprise bit-pairs, each of a systematic bit and parity bit. Systematic bits are preferably mapped to high reliability bit positions in TDD HSDPA, achieving a performance gain of between 0.2 dB and 0.5 dB. The forwards/reverse mapping allows a degree of interleaving that improves system performance in fading channels or channels disturbed by short time period noise or interference.

Abstract: Disclosed is a method and an apparatus for transmitting/receiving signals in an multiple input multiple output (MIMO) wireless communication system. The method and apparatus including beam forming of a reference signal while predetermined codes are mapped on a one-to-one basis to each of a plurality of beams available for the transmitter and thereafter transmitting the beam-formed reference signal to a receiver. Also, if information representing an optimum beam, which maximizes reception performance, is received from the receiver, beam forming of data signals is performed by means of a beam corresponding to the information on the optimum beam and the beam-formed data signals are transmitted to the receiver. Therefore, it is possible to apply a beam forming scheme having minimum operation complexity and maximizing reception performance.

Abstract: A driving device includes a plurality of transmitters. Each transmitter includes a first current source, a second current source, a third current source, a fourth current source, a first switch, a second switch, a third switch, a fourth switch, a fifth switch, and a sixth switch. The first and the fourth switches are controlled by a first control signal. The second and the third switches are controlled by a second control signal. The second switch is coupled to the first switch. The third switch is coupled to the first current source. The fourth switch is coupled to the third switch and the second current source. The fifth and the sixth switches are controlled respectively by a third and a fourth control signal. The fifth switch is coupled to the third current source and the first switch. The sixth switch is coupled to the second switch and the fourth current source.

Abstract: In a communication system, when packet data units (PDUs) to be transmitted from a transmitter apparatus are modulated according to Orthogonal Frequency Division Multiplexing (OFDM), the waveforms representing the modulated PDUs will experience different peak to average ratio values (PAR) making the PDUs differently sensitive to non-ideal transmitter characteristics. To minimize errors in the transmitted PDUs, at least two PDUs (304, 305, 306) are scrambled and modulated in parallel and substantially simultaneously in the transmitter (100), and the PAR values of the at least two PDUs (304, 305, 306) are determined at each transmit instance. The measured PAR values of the at least two PDUs are compared in a scheduler (310), and the scheduler selects for transmission the PDU with the lowest PAR value. The scheduler (310) then instructs the transmitter (100) to transmit the selected PDU.

Abstract: A FAWNA that allows high-speed mobile connectivity by leveraging the speed of optical networks. Specifically, SIMO FAWNA, which comprises a SIMO wireless channel interfaced with a fiber channel through wireless-to-optical interfaces. Received wireless signal at each interface are sampled and quantized prior to transmission. The capacity of the FAWNA approaches the capacity of the architecture exponentially with fiber capacity. It is also shown that for a given fiber capacity, there is an optimal method of operating wireless bandwidth and number of interfaces. An optimal method to divide the fiber capacity among the interfaces is shown, which ensures that each interface is allocated a rate so that noise is dominated by front end noise rather than by quantization distortion. A method is also presented in which, rather than dynamically changing rate allocation based on channel state, a less complex, fixed rate allocation may be adopted with very small loss in performance.

Abstract: A radio communication system includes a remote device radio, and a base station radio operable to communicate with the remote device radio at a first channel and at a second channel using non-simultaneous frequency diversity. The base station is operable to communicate with a device other than the remote device at the second channel while the remote device radio and the base station radio are communicating at the first channel. A radio using non-simultaneous frequency diversity includes an antenna, a radio frequency module coupled to the antenna such that the radio frequency module is operable to transmit or receive radio frequency signals at a first channel and signals at a second channel using the antenna, and a baseband module coupled to the radio frequency module. The baseband module operable to transmit or receive signals through the radio frequency module, such that signals transmitted or received by the radio employ non-simultaneous frequency diversity using the first channel and the second channel.

Abstract: Provided are a transmission/receiving apparatus and method of switching a transmission antenna in a Transmission Switched Diversity (TSD) system.

Abstract: The present invention describes a spread spectrum communication system wherein the frequency of carriers and the code channels of the carriers or both for transmission to a given remote station user vary in time. This provides for a direct sequence spectrum communications system which changes frequency or code channel according to a predetermined pattern. The code channels and frequencies can be determined in accordance with a deterministic function or based upon a subset of the data to be transmitted. A receiver structure is also described for receiving the same.

Abstract: Transmitter architectures designed to accommodate both constant and non-constant of envelope modulation schemes and capable of providing local oscillator carrier frequencies within any one of numerous desired frequency bands, thus allowing compliance with many different communication standards. One example of a programmable frequency synthesizer includes a plurality of transmitter components and a microcontroller coupled to the frequency synthesizer and to the plurality of transmitter components. The microcontroller is adapted to provide a frequency control signal to the frequency synthesizer to control a frequency of the local oscillator carrier frequency.

Abstract: In an information transmission method, a radio communications system, a base station and a mobile station, a TBS size, a modulation scheme and the number of codes in a multicode are converted into identification data having a relatively smaller data size before being transmitted to a destination of communication. The TBS size is identified by using, in combination, an identification code identifying a channelization code set, an identification code identifying a modulation scheme, and an identification code obtained by converting a combination of the number of codes in a multicode and a modulation pattern identification (TFRC) into a corresponding code. Accordingly, the data size for TBS size identification is reduced.

Abstract: The invention provides a block-wise successive interference cancellation (SIC) detection algorithm for a general multi-input multi-output (MIMO) CDMA system over the frequency-selective channels, in which each user's data stream can be simultaneously applied with orthogonal space-time block encoding for transmit diversity or spatially multiplexing for high spectral efficiency according to the channel conditions. For such the considered dual-signaling system, the receiver could suffer from the large dimension data processing. A two-stage approach for block-wise SIC detection algorithm is thus proposed to further reduce the computational complexity.

Abstract: A transmission apparatus used in a radio communication system adopting the OFDM scheme is disclosed. The transmission apparatus includes: a dividing inverse Fourier transform part including plural transform parts, wherein the dividing inverse Fourier transform part divides a signal to be transmitted into plural signals, and each of the plural transform parts performs inverse Fourier transform on one of the plural signals; a peak control part for outputting a peak control signal based on peaks that are detected from output signals of the dividing inverse Fourier transform part; and a peak reducing process part for adjusting a weight or an arranging order of an output signal of the dividing inverse Fourier transform part according to the peak control signal to output an adjusted signal, and synthesizing the adjusted signal with other signal so as to output a synthesized signal.

Abstract: A current steering mechanism is provided in a radio transmitter (e.g., a multiband radio transmitter) to provide compatibility with a variety of baseband parts. Different proportions of an input signal current (“in”) may be steered to a dummy load (103), a mixer for a first band (106), and a mixer for a second band (108). In one example, five different loads are provided, one dummy load (103) and two different loads (105, 107) for each band. Possibilities include: 1. All current steered into dummy load via transistor A; 2. All current steered into Band 1 mixer via transistor B; 3. All current steered into a Band 1 mixer via transistor C, causing 6 dB input signal amplification; 4. All current steered into Band 2 mixer via transistor E; 5. All current steered into a Band 2 mixer via transistor D, causing 6 dB input signal amplification; 6. Like cases 2-5 but with diversion of some portion of current via a dummy load for attenuation of input signal in 1 dB steps.

Abstract: A transceiver system includes a first section coupled to a first antenna, a second section coupled to a second antenna, and a radio frequency (RF) unit. The first section includes a transmit path and a first receive path for a first (e.g., GSM) wireless system, a transmit path and a first receive path for a second (e.g., CDMA) wireless system, and a transmit/receive (T/R) switch that couples the signal paths to the first antenna. The second section includes a second receive path for the first wireless system and a second receive path for the second wireless system. The first and second receive paths for the first wireless system are for two frequency bands. The first and second receive paths for the second wireless system are for a single frequency band and provide receive diversity. The transceiver system may include a GPS receive path coupled to a third antenna.

Abstract: A system for identifying radio-frequency identification (RFID) devices is described. In one embodiment, RFID devices include an antenna and metallic pattern printed on a substrate. A probing platform is used to radiate the RFID devices with an electromagnetic signal (e.g., radio-frequency signal, microwave signal, etc.). Each RFID device generates a quantifiable backscatter depending on the unique impedance of the passive RFID device in response to the electromagnetic signal. The backscatter is employed to uniquely identify the passive RFID device's impendence with respect to the probing platform uniquely characterized at predetermined frequencies of the electromagnetic signal.

Abstract: A method for fine timing synchronization is provided. The method comprises: detecting an end point of the short preamble; delivering the samples after the end point to a matched filter to generate a plurality of correlation peaks; searching the correlation peaks generated from the samples of the first LTS for a first maximal peak point which is the correlation peak with a first maximal intensity, and obtaining the first time index of the first maximal peak point; searching the correlation peaks generated from the samples of the first LTS for a pre-peak point which is the correlation peak forming a peak intensity appearing before and nearest to the first maximal peak point, and obtaining the second time index of the pre-peak point; estimating a third time index of the start point of the second LTS according to the first and second time indexes.

Abstract: A multi-frequency wireless transmitter is provided for use in automated security systems. The multi-frequency wireless transmitter transmits a message over a plurality of frequencies, thus diminishing the effects of noise interference. The transmitter includes a frequency generator capable of selectably generating a plurality of frequencies lying within the 260 to 470 MHz frequency band. An RF power amplifier having multiple power output values selectable to match with the selected generated frequency regulates the transmit power.

Abstract: A system for dynamically adapting the communication characteristics of a multiple antenna system (MAS) with multi-user (MU) transmissions (defined with the acronym MU-MAS), such as a distributed-input distributed-output (DIDO) communication system. For example, a system according to one embodiment of the invention comprises: one or more coding modulation units to encode and modulate information bits for each of a plurality of wireless client devices to produce encoded and modulated information bits; one or more mapping units to map the encoded and modulated information bits to complex symbols; and a MU-MAS or DIDO configurator unit to determine a subset of users and a MU-MAS or DIDO transmission mode based on channel characterization data obtained through feedback from the wireless client devices and to responsively control the coding modulation units and mapping units.

Abstract: A system for compensating for in-phase and quadrature (I/Q) imbalances for multiple antenna systems (MAS) with multi-user (MU) transmissions (defined with the acronym MU-MAS), such as distributed-input distributed-output (DIDO) communication systems, comprising multicarrier modulation, such as orthogonal frequency division multiplexing (OFDM).

Abstract: Disclosed is a remote access unit for transmitting and receiving upstream and downstream data in which channels having different transmission scheme are multiplexed, and an optical network for bi-directional wireless communication using same. The remote access unit includes an antenna for receiving the downstream data and wirelessly transmitting same and for receiving the upstream data and providing same to the remote access unit, a switch for outputting downstream time division channels of the downstream data to the antenna and for receiving upstream time division channels of the upstream data from the antenna, and a controller for controlling the switch in order to prevent the upstream and downstream time division channels from overlapping.