Abstract: Systems, methods, and devices for mixed voice and spread spectrum data signaling with enhanced concealment of data are disclosed. Audible artifacts may be reduced or suppressed in order to improve the audible quality of the sound. The distortion to the audio may be kept just below perceptibility, yet the data contained within the modulated signal is recoverable on the receiving side. The recovery of the data is robust to the impairments imposed by the communication channel. The disclosed systems, methods, and devices may be implemented in audio conferencing or video conferencing. Various embodiments of the present disclosure provide a data and voice mixer, which includes an improved spread spectrum data hiding transmitter. The transmitter may comprise a spreading encoder, a Phase Shift Keying (PSK) modulator, and a notch filter. A pseudo random switching pattern may be applied to a plurality of chip sequence generators in order to reduce or suppress an undesirable audible artifact.

Abstract: A method of transmitting a broadcast signal in a transmitter includes transmitting a transmission frame including a plurality of slots during which data groups of mobile data are transmitted, the mobile data being encoded through a Reed-Solomon (RS) frame and each row of a payload of the RS frame including a transport packet of the mobile data.

Abstract: A spread-spectrum signal comprises a spreading waveform modulating a carrier wave and containing a real linear combination of a first waveform at a first waveform rate and a second waveform at a second waveform rate, the first waveform rate being distinct from the second waveform rate and both waveform rates being distinct and non-zero. The linear combination of the first and the second waveform is modulated with at least one binary sequence comprising a signal identification code.

Abstract: A signal compression method and apparatus for a base transceiver system (BTS) in a wireless communication network provides efficient transfer of compressed signal samples over serial data links in the system. For the uplink, an RF unit of the BTS compresses signal samples resulting from analog to digital conversion of an analog signal received via an antenna. The RF unit transfers the compressed signal samples over the serial data link to the base station processor where they are decompressed prior to the normal signal processing operations. For the downlink, the base station processor compresses signal samples and transfers the compressed signal samples over the serial data link to the RF unit. The RF unit decompresses the compressed samples and converts the decompressed samples to an analog signal for transmission over an antenna. Compression and decompression can be incorporated into operations of conventional base stations and distributed antenna systems.

Abstract: Decreased capability for detection of communications signals by an adversary is provided by applying frequency hopping, frequency chirping, and direct sequence spreading to the signals. The frequency hopping and frequency chirping can be driven by pseudo random functions. The direct sequence spreading can use a pseudo random chip sequence.

Abstract: A method and apparatus for utilizing code division multiple access in modulated reflectance transmissions comprises the steps of generating a phase-modulated reflectance data bit stream; modifying the modulated reflectance data bit stream; providing the modified modulated reflectance data bit stream to a switch that connects an antenna to an infinite impedance in the event a “+1” is to be sent, or connects the antenna to ground in the event a “0” or a “?1” is to be sent.

Abstract: A dual burst transmitter for ultra-wideband (UWB) communication systems generates a pair of precisely spaced RF bursts from a single trigger event. An input trigger pulse produces two oscillator trigger pulses, an initial pulse and a delayed pulse, in a dual trigger generator. The two oscillator trigger pulses drive a gated RF burst (power output) oscillator. A bias driver circuit gates the RF output oscillator on and off and sets the RF burst packet width. The bias driver also level shifts the drive signal to the level that is required for the RF output device.

Abstract: A method and apparatus are disclosed for modulating a communication signal in a code division multiple access (CDMA) environment using orthogonal N by N Hadamard spread spectrum codes Orthogonal spreading codes are used that have lengths that are not a power-of 2 to provide additional channel variability for various multimedia applications and increase the flexibility of the number of channels/bandwidth relationship. The Hadamard codes are multiples of 4 (4n) and demonstrate a good cross-correlation property, making them very useful in the flexible design of code division multiple access (CDMA) systems. A transmitter encodes each of N data streams (N not being a power of 2), to be transmitted using a 4n codeword, Ni. The received signal is passed through a filter matched to the characteristics of the appropriate codeword, Ni, and PN spreading sequence.

Abstract: A system and method for low complexity frequency hopping simulation for communication device performance testing is disclosed. A baseband and channel model combination in a baseband processing module (602) of a testing system (600) reduces the required number of computations while retaining accuracy. A simulated channel is generated (612) with a bandwidth required for frequency hopping, and the hopping is simulated by shifting (614) the channel (612) instead of the signal (606). Signal attenuation by the shifted channel (615) is modeled in the baseband processing module (602), and the resulting simulated signal (610) is then up-sampled (628) to the proper frequency for output to the test device (634).

Abstract: A method of providing frame synchronization for GPS signals can include performing coherent bit extraction on the GPS bits and then performing coherent frame boundary detection based on the bits of the coherent bit extraction. Concurrently, differential bit extraction on the GPS bits and differential frame boundary detection based on bits of the differential bit extraction can be performed. Whichever of the coherent frame boundary detection and the differential frame boundary detection first finds a frame boundary, then that frame boundary is used for the frame synchronization. A method of providing string synchronization for GLONASS signals includes performing coherent and differential bit extraction on the GLONASS bits.

Abstract: A near field RF communicator has: an antenna operable to generate an RF signal to enable inductive coupling via the magnetic field of the RF signal between the antenna and another near field RF communicator or RF transponder in near field range; and a signal generator operable to generate a multi-level digital sine wave drive signal to drive the antenna to generate the RF signal, wherein the signal generator comprises a selector operable to select one or more digital sequences to provide one or more digital signals from which the digital sine wave drive signal is generated.

Abstract: The invention proposes a data transmission process, from a first unit (1) situated at a predetermined depth of an oil well to a second unit (2) situated at the surface of this well, the process comprising a digital-analog conversion stage (8) of the data to obtain an analog signal forming support of the data, and an amplification stage (9) of this signal prior to its emission in a cable (11) connecting the two units, characterized in that at least two distinct scramblings (20, 21) of the data are completed, such that there is a first and a second set of scrambled data. After passage in a single complex inverse Fourier transform, that intended for emission is selected (26), whereof the dynamic in amplitude is the lowest. If the probability of saturating with a single set is 10?q, then due to this process the probability will be 10?2q.

Abstract: A method and an apparatus for efficient Gold code generation and management in WCDMA systems are presented. Aspects of the method may include simultaneously generating, based on the codeword sequence, a plurality of scrambling code segments associated with a scrambling code. A plurality of scrambling code segments, where each is associated with a corresponding one of a plurality of scrambling codes, may also be simultaneously generated. The plurality of scrambling codes may form a scrambling code group. Based on the codeword sequence, a plurality of time shifted versions of at least one scrambling code segment associated with a scrambling code may also be simultaneously generated.

Abstract: The present invention considers a direct sequence spread spectrum system wherein every user employs the same spreading code. In a preferred embodiment, received signal is correlated with the training signal. Peaks of correlator output are used to identify the delays corresponding to the significant multipath components. The delays that are within a predetermined number of chips of each other are associated with a hypothesized user. In an alternate embodiment, a user separation technique is used which is based on the observation that after the training period, different users send uncorrelated data. In another alternate embodiment, linear minimum mean squared error (LMMSE) based correlators locked to individual users are employed. These correlators only provide multipath components of their corresponding users as output.

Abstract: Provided is a wireless communication system including a first radio equipment that transmits first data using first radio waves, a data transmitter that outputs a second radio wave generated by modulating the first radio wave according to second data to be transmitted, and a second radio equipment that receives the first radio wave and the second radio wave, and separates and demodulates the first data transmitted from the first radio equipment and the second data transmitted from the data transmitter contained in the received radio waves.

Abstract: Noise measurements are made within a fraction of a single symbol period of a longest orthogonal code symbol. A control processor identifies an unoccupied code having a spreading factor that is less than a longest spreading factor for the system. A despreader measures symbol energy based on the unoccupied code and a noise estimator generates noise estimations based on the measured symbol energies. The subscriber station uses similar techniques in order to perform channel estimations within a period that is a fraction of a symbol period of a longest-spreading-factor code.

Abstract: Orthogonal Code Division Multiplexing (OCDM) transceiver system with Complementary Code Keying (CCK) and method for baseband OCDM-CCK encoding and decoding are provided. The OCDM-CCK method comprises a serial-to-parallel data converter converting a stream of M*n-bit serial data to n-bit parallel data in ‘M’ parallel baseband paths, and encoding each n-bit data segment with a distinct complementary code using CCK modulation for spreading. The CCK encoded baseband signals are all summed and transmitted simultaneously on the same carrier frequency and spread spectral bandwidth. The OCDM-CCK method of encoding and transmission of information, results in enhanced datarates of 33 Mbps, 88 Mbps, 176 Mbps and higher multiples of 5.5 Mbps with backward compatibility for IEEE 802.11b WLAN (Wireless Local Area Network), and wireless communication networks supporting real time Direct Sequence Spread Spectrum (DSSS).

Abstract: Method for generating reference signal sequence using grouping is explained. In this method, base sequences are grouped such that each group contains at least one base sequence of each length, so UE(s) can use various length sequences as a reference signal. And in this method, inter cell interference caused by using various length sequence as a reference signal sequence can be minimized by grouping sequences having the high cross correlation relation.

Abstract: A rake receiver comprises a plurality of receive antennas and a processing system. Each receive antenna has a plurality of demodulation elements. The processing system is configured to assign a plurality of demodulation elements from a plurality of receive antennas to a multipath group, assign the multipath group to a multipath signal, and independently adjust a time delay value of each demodulation element in the multipath group to correspond to a local time delay of the multipath signal at the corresponding receive antenna.

Abstract: A method, a process and an audio system for embedding bit stream in a voice signal is disclosed. A voice/data interference signal is composed and supplied to the mixer of the voice signal and the data signal such that the resulting mixed signal effectively cancels the interference and allows the interference-free signal being transmitted to the audio signal receiver/decoder. The decoder may decode the data without interference errors. A method using profile shaping to mask the noise due to modulated carrier signal is also disclosed.

Abstract: A method for converting source data to a channel-modulated signal having a plurality of pairs of in-phase (I) and quadrature-phase (Q) data in a mobile station, wherein the mobile station uses at least one channel, includes the steps of: a) encoding the source data to generate at least one data part and a control part; b) generating at least one spreading code to be allocated to the channel, wherein each spreading code is selected on the basis of a data rate of the data part and the control part and spreading codes are selected so that two consecutive pairs of the I and Q data are correspondent to two points located on same point or symmetrical with respect to a zero point on a phase domain; and c) spreading the control part and the data part by using the spreading code, to thereby generate the channel-modulated signal. The method is capable of improving a power efficiency of a mobile station by reducing a peak-to-average power ratio in a mobile communication system.

Abstract: A user equipment locally stores a shift pattern that is specific to a cell to which the user equipment is currently attached, and processes a group of modulation symbols or bits for uplink transmission by a) cyclically shifting the modulation symbols or bits within the group according to the stored cell-specific shift pattern, and b) applying a spreading code to the group of symbols or bits. Different embodiments include spatial shifting and frequency bin shifting.

Abstract: Method for generating reference signal sequence using grouping is explained. In this method, base sequences are grouped such that each group contains at least one base sequence of each length, so UE(s) can use various length sequences as a reference signal. And in this method, inter cell interference caused by using various length sequence as a reference signal sequence can be minimized by grouping sequences having the high cross correlation relation.

Abstract: Method for generating reference signal sequence using grouping is explained. In this method, base sequences are grouped such that each group contains at least one base sequence of each length, so UE(s) can use various length sequences as a reference signal. And in this method, inter cell interference caused by using various length sequence as a reference signal sequence can be minimized by grouping sequences having the high cross correlation relation.

Abstract: A device for fast transition from preamble synchronization of a received baseband signal to demodulation of the received baseband signal may include a baseband chip tracking loop to generate an offset tracking value to track any initial chip phase offset and Doppler-caused baseband chip frequency drift associated with the received baseband signal. The device may also include a numerical controlled oscillator to correct any Doppler-caused phase rotation associated with the received signal. The device may additionally include a preamble synchronization unit to detect a preamble of the received baseband signal, and to measure a chip phase offset and a baseband Doppler frequency shift associated with the received baseband signal. The chip phase offset may be used to set an initial chip phase offset value of the chip tracking loop so that the chip tracking loop starts with approximately a zero pull-in error.

Abstract: A method of delay spread compensation, suitable for use in a communication device a having plurality of receiver antennas, is disclosed. The method comprises receiving a plurality of signals, each via a respective antenna, wherein each signal comprises a signal component corresponding to a transmitted signal, and wherein each received signal experiences a respective channel impulse response having a corresponding delay spread; determining estimates of each of the channel impulse responses; calculating post-coding characteristics based on the estimates of the channel impulse responses; and post-coding the plurality of received signals using the post-coding characteristics to produce at least a first delay spread compensated signal. Corresponding computer program product, processing arrangement and communication device are also disclosed.

Abstract: There is provided a method for generating an error signal for an automatic frequency control (AFC) loop in a Code Division Multiple Access (CDMA) system. Sign information relating to phase differences in received pilot signals is accumulated. In one embodiment, the accumulated sign information is compared against predetermined threshold levels. The error signal is generated when at least one of the predetermined threshold levels is satisfied. In a second embodiment, the accumulated sign information is decimated. An output of the decimating step is utilized as the error signal for the AFC loop.

Abstract: In a communication system including a plurality of pairs of a transmitting device 2 and a receiving device 3, the transmission performance in the pairs is to be improved. The transmitting device 2-k transmits a transmission signal sk(t) to the receiving device 3-k a plurality of number of times. The receiving device 3-k updates the weight matrix Wk and the hopping pattern Pk used by the FIR filter which performs filtering on the transmission signal rk(t) at a predetermined time interval. The receiving device 3-k transmits the updated hopping pattern Pk to the transmitting device 2-k. The transmitting device 2-k receives the hopping pattern Pk to be used for subsequent spread spectrum.

Abstract: A mechanism for processing beamforming steering matrices in a transceiver system. A plurality of beamforming steering matrices associated with a plurality of subcarriers of an RF signal received at the transceiver system are generated. The beamforming steering matrices are compressed and stored. The beamforming steering matrices may also be grouped or sub-sampled prior to being stored. The beamforming steering matrices are decompressed and ungrouped before being applied to data to be transmitted. Prior to ungrouping the beamforming steering matrices, a phase difference between corresponding beamforming steering vectors of consecutive beamforming steering matrices is determined. Phase rotation is performed on the corresponding beamforming steering vectors based on the determined phase difference associated with the corresponding beamforming steering vectors to improve phase continuity between consecutive beamforming steering matrices.

Abstract: A system and method for transferring high-definition multimedia signals over four twisted-pairs. The system includes a multimedia source for transmitting multimedia data and source-to-sink management data to a multimedia sink over a first channel, a second channel and a third channel wherein the multimedia source is further being capable of transmitting a clock signal to the multimedia sink over a fourth channel; and a multimedia sink for transferring sink-to-source management data to the multimedia source over the fourth channel. The clock signal and the sink-to-source management data are simultaneously transmitted over the fourth channel. Each of the channels comprises a single twisted-pair, thereby the channels can bounded in a twisted pair type cable comprising at least one of: Category 5, Category 5e, Category 6, and Category 6e.

Abstract: Methods and systems for demodulating a multiuser signal using channel decoders for a multiple-access communication system are disclosed. According to one method, a signal containing information for a plurality of users in a multiple-access communication system employing spreading sequences is received. The received signal is despread using a signature sequence for each user to produce individual user signals having multiple-access interference (MAI). Channel estimates associated with each of the individual user received signals are determined. Each of the individual user signals are decoded using a channel decoder with a log-likelihood ratio (LLR) that accounts for the time-varying variance of the MAI in the individual user signals based on a model of the MAI including the channel estimates of the received signals of other users.

Abstract: Amplifier for an ultra-wideband (UWB) signal receiver having a signal input (15) for receiving an ultra-wideband signal which is sent by a transmitter (1) and which is transmitted in a sequence of transmission channels (Ki) (which each have a particular frequency bandwidth) which has been agreed between the transmitter (1) and the receiver (4); a transistor (18) whose control connection is connected to the signal input (15); a resonant circuit (26, 30, 31) which is connected to the transistor (18) and whose resonant frequency can be set for the purpose of selecting the transmission channel (Ki) in line with the agreed sequence of transmission channels; and having a signal output (29) for outputting the amplified ultra-wideband signal, the signal output being tapped off between the transistor (18) and the resonant circuit.

Abstract: A mobile communication system includes: a base station configured to form a cell and transmit a downlink signal which has been spread with a downlink scrambling code, toward the cell; a mobile station connected with the base station by radio when the mobile station is in the cell, and configured to communicate with a counter side station through the base station; and a relay station configured to receive the downlink signal, generate a limitation downlink signal showing a limitation area in which a function of the mobile station is limited, based on the downlink signal, and transmit the limitation downlink signal which has been spread with a specific scrambling code different from the downlink scrambling code, toward the limitation area. The downlink signal contains a base station peripheral cell list showing a scrambling code used in another base station on a periphery of the base station.

Abstract: The present invention is provided with a wireless transceiver and wireless transmitting/receiving method and program thereof capable of improving the robustness against Doppler frequency by containing transmit diversity signals in one spreading region. In the present invention, the transmitter encodes the transmit signals using a space-time matrix and transmits the encoded space-time signals after being spread with different spreading codes, and the receiver de-spreads the received spread signals, in unit of time slot, with the spreading codes corresponding to the respective time slots and then decodes the de-spread signals using the space-time matrix.

Abstract: A method for converting source data to a channel-modulated signal having a plurality of pairs of in-phase (I) and quadrature-phase (Q) data in a mobile station, wherein the mobile station uses at least one channel, includes the steps of: a) encoding the source data to generate at least one data part and a control part; b) generating at least one spreading code to be allocated to the channel, wherein each spreading code is selected on the basis of a data rate of the data part and the control part and spreading codes are selected so that two consecutive pairs of the I and Q data are correspondent to two points located on same point or symmetrical with respect to a zero point on a phase domain; and c) spreading the control part and the data part by using the spreading code, to thereby generate the channel-modulated signal. The method is capable of improving a power efficiency of a mobile station by reducing a peak-to-average power ratio in a mobile communication system.

Abstract: Systems and methods for communicating with acoustic signals and, more particularly, systems and methods for communicating using direct-sequence spread spectrum acoustic waves generated by non-impulsive sources. A data signal is modulated by a pseudorandom noise signal and the modulated spread spectrum signal is coupled to a transmission medium for propagation of an acoustic wave through the medium. Acoustic signals are received from the medium and are possessed to obtain a transmitted data signal.

Abstract: In one aspect of a multiple-access OFDM-CDMA system, data spreading is performed in the frequency domain by spreading each data stream with a respective spreading code selected from a set of available spreading codes. To support multiple access, system resources may be allocated and de-allocated to users (e.g., spreading codes may be assigned to users as needed, and transmit power may be allocated to users). Variable rate data for each user may be supported via a combination of spreading adjustment and transmit power scaling. Interference control techniques are also provided to improve system performance via power control of the downlink and/or uplink transmissions to achieve the desired level of performance while minimizing interference. A pilot may be transmitted by each transmitter unit to assist the receiver units perform acquisition, timing synchronization, carrier recovery, handoff, channel estimation, coherent data demodulation, and so on.

Abstract: In a mobile communication system according to the present invention, a reference signal sequence includes a plurality of signal sequences assigned in slot units in the predetermined physical channel based on a hopping pattern and a sequence shift pattern; the hopping pattern is configured to be determined based on a slot number and an SFN in the predetermined physical channel or the predetermined physical signal; the sequence shift pattern is configured to be determined based on the identification information of the cell to which the predetermined physical channel or the predetermined physical signal has been set; and the hopping cycle is configured to be determined based on a cycle of the slot number and an SFN cycle.

Abstract: A method for wirelessly transmitting management data without cables in a data center is provided. Management data is obtained at a device in the data center. A wireless management data signal is generated from the management data. The wireless management data signal is configured to be transmitted at frequencies matching an ambient electromagnetic noise emitted by the data center, such that the wireless management data signal is masked in the ambient electromagnetic noise emitted by the data center. The wireless management data signal is wirelessly transmitted to another device.

Abstract: At least a portion of a total spectrum bandwidth of a wireless system may be allocated to each of a plurality of users by assigning at least one unique spreading code to each of the plurality of users. At least two of the plurality of users may have different spectrum capabilities and may transmit simultaneously. Each of the assigned spreading codes may have a different code length. The number and/or the code length of the spreading codes assigned to each user may be indicative of a portion of the total spectrum bandwidth allocated to each user.

Abstract: A multicarrier communication apparatus that is capable of suppressing interference of feedback information with other channels and alleviating a reduction in an uplink capacity. In PL signal reception section (260) of this apparatus, PL signal extraction section (261) extracts pilot signals and reception quality measuring section (262) measures reception quality such as an SIR. Here, since pilot signals are included in respective subcarriers, reception quality measuring section (262) measures reception quality of subcarriers. FBSC determining section (270) determines a feedback information subcarrier based on the reception quality of subcarriers. More specifically, FBSC determining section (270) determines a subcarrier having the highest reception quality as a feedback information subcarrier. FBSC determining section (270) outputs information about the feedback information subcarrier (FBSC information) to control CH transmission section (110) and FB information reception section (250).

Abstract: A disclosed signal transmitting method includes the steps of a) categorizing plural digital signals, obtained by performing A/D conversion on plural analog signals consecutively arranged in a time direction, into plural signal groups in an order starting from lower bits of the plural digital signals, b) performing code spreading on the plural digital signals by using a different spread frequency for each signal group and using different spread codes for each bit, c) multiplexing the spread digital signals, and d) transmitting the multiplexed plural digital signals.

Abstract: An apparatus and method for correlating a signal over a correlation interval while accommodating spreading code frequency offset is described. In one embodiment, the apparatus includes a plurality of correlators, where each correlator forms a correlation result corresponding to a unique code frequency offset hypothesis. Each correlator selects samples from a tapped delay line at a tap position moved along the delay line at a rate corresponding to the correlator unique code frequency offset hypothesis.

Abstract: An electric wave receiving apparatus comprises: an antenna; an amplifier; filter circuits that extract signals in different frequency bands from an output of the amplifier; detector circuits that demodulate time codes from outputs of the filter circuits; automatic gain control circuits that generate gain control signals from the detector circuits; a selector that selects one gain control signal indicating a maximum signal level among the gain control signals; and an arithmetic processing section to be able to analyze the time codes of outputs of the plurality of detector circuits, wherein the one gain control signal is supplied to the amplifier to control an amplification factor of the amplifier so that signal levels output from detector circuits do not become excessive, and the arithmetic processing section selects an output to enable the analysis of the time code among the outputs of detector circuits to perform the analysis of the time code.

Abstract: In receiving equipment such as a mobile terminal (1) for decoding received signals coded according to a CDMA method are decoded in an intermediate processor (9). In the decoding, coefficients or elements of a vector w are calculated in a unit or module (13) by an iterative method as a solution to a system of linear equations represented by the matrix equation Rw=h, where R is a matrix of known elements and h is a known vector. For terminating the iteration, a value of the signal to interference plus noise ratio SINR for the received signals is calculated in each iteration step and then this calculated value or a quantity derived therefrom is used as a stopping criterion or generally in a stopping algorithm.

Abstract: This disclosure relates to method, device and system for detecting errors in a communication system. A signal is received from a transmitter at a receiver wherein the signal includes a data portion and a result of a hash function. The hash function is computed in part from a transmitter identification code. The receiver determines if the result of the hash function matches both the data portion and the transmitter identification code. The receiver discards the signal if the result of the hash function does not match both the data portion and the transmitter identification code of the transmitter.

Abstract: A method is provided for correlating samples of a received signal and samples of an internally generated/stored sample sequence (“IGSSS”). The method involves performing a first iteration of a first-resolution correlation state. The first-resolution correlation state involves: selecting a first N sets of samples from the received signal; selecting a first set of samples from the IGSSS; and concurrently comparing each of the N sets of samples with the first set of samples to determine if a correlation exists between the same. If it is determined that a correlation does not exist between one of the N sets of samples and the first set of samples, then a second iteration of the first-resolution correlation state is performed. If it is determined that a correlation exists between one of the N sets of samples and the first set of samples, then a first iteration of a second-resolution correlation state is performed.

Abstract: Disclosed is a wireless communication terminal device that is capable of preventing inter-coding interference upon each of a plurality of base stations, even when the timing changes for a transmission of a control signal that is CoMP received by the plurality of base stations. Upon the device, a diffusion unit (214) employs any of a plurality of ZAC series that are reciprocally splittable with a reciprocally variable cyclical shift quantity to diffuse a response signal, according to an instruction from a control unit (209), and the control unit (209) controls, according to a difference between a timing of a transmission of a response signal at a first time and a timing of a transmission of a response signal at a second time that is later than the first time, the cyclical shift quantity of the ZAC series that is employed by the diffusion unit (214) at the second time.

Abstract: A UWB transmitting/receiving apparatus, a UWB transmitting/receiving terminal apparatus and a UWB transmitting/receiving system wherein a possibly reduced number of data retransmissions is achieved so as to raise the transmission efficiency. A UWB transmitting/receiving apparatus (100), which performs a UWB transmission, comprises a receiving part (400) that receives a propagation environment determination pulse transmitted from a UWB transmitting/receiving terminal apparatus (200), which also performs a UWB transmission, and a transmitting part (300) that transmits a data signal while the receiving part (400) is receiving the propagation environment determination pulse.

Abstract: A secure information transmission system includes one or more transmitters and one or more receivers. The transmission waveform employed includes highly randomized, independent stochastic processes, and is secured as a separate entity from the information it carries. The signal, using novel modulation methodology reducing impulse responses, has a paucity of spectral information and may be detected, acquired and demodulated only by communicants generating the necessary receiving algorithm coefficients. The physical area of signal reception is restricted to that of each intended communicant, reception areas following movements of mobile communicants. A unique instant in time is used as basis for communications keys to the securing algorithms dynamically generated on a one-time basis and never exchanged or stored by communicants.