Abstract: A GPS positioning method is disclosed which can shorten the time required until positioning arithmetic operation is started after power is made available. An oscillation frequency of a reference frequency oscillator used in a GPS receiver section or a frequency variation of the oscillation frequency is measured using high precision frequency information provided by a standard wave. A result of the measurement is utilized to catch a signal from a GPS satellite. Further, a synchronization timing of a spread code of the spread spectrum signal from the satellite is detected to detect a small time component for time synchronization. After synchronization of the spread code is completed, a time of the boundary of one period of the spread code is detected from time information provided by a standard wave, and a time component greater than the small time component for time synchronization is detected based on the time of the boundary.

Abstract: A plurality of data signals are received over an antenna array having a plurality of antenna elements. The data signals are transmitted over a shared spectrum in a wireless communication system. A signal having each of the data signals is received over each antenna element. The plurality of data signals are grouped into a plurality of groups. The received signals of the antenna elements are matched filtered for a first group of the plurality of groups, producing a matched filtered result. Data is jointly detected of the first group using the matched filtered result. An interference correction signal is constructed using the detected data for each antenna element. The interference cancelled result is subtracted from the received signal of each antenna element, producing an interference cancelled result for each antenna element. Data is successively detected for remaining groups using the interference cancelled result for each antenna element.

Abstract: A method and apparatus for reducing an amount of bits of data at at least two stages of data transfer in a communications reception data path between a rake receiver and a channel decoder.

Abstract: Equalizing method and apparatus for single carrier system having an improved equalization performance is disclosed, which includes: a section setting unit for setting filter taps having a predetermined section corresponding to the predicted multi-path; a repeat setting unit for setting filter taps of a repetition section by making the set predetermined section repetitive periodically; and a filter unit for filtering the multi-path by updating the coefficients of the filter taps of the set repetition section. The repeat setting unit sets the filter taps of the repetition section corresponding to an operation characteristic of the filter unit. Accordingly, the apparatus can improve equalization performance by setting filter taps corresponding to the predicted multi-path and updating only the set coefficients of the filter taps. Further, the apparatus can improve equalization performance in dynamic channel circumstances in which the multi-path changes.

Abstract: A method for detecting a periodic signal in a communication system. The method includes converting a time domain digitized signal to obtain a corresponding frequency domain digitized signal, quantizing at least two symbols of the frequency domain digitized signal to obtain quantization information, utilizing the quantization information to compute a detection metric for periodic signal detection, and determining that a periodic signal is detected if the detection metric is greater than a predetermined threshold.

Abstract: A device and a method for determining a reference level for automatic gain control of a radio frequency signal to be received, particularly having a varying strength, in which method radio blocks are received on a logical general packet data traffic channel of a signal, which radio blocks have been transmitted with a predetermined transmission power level and by using a predetermined way of controlling the transmission power level. In the invention, said reference level is continuously determined on the basis of correctly received or valid radio blocks, wherein the reference level is corrected on the basis of the signal strength measured during the reception of each valid radio block.

Abstract: An adaptive multiple-tap frequency domain digital filter processes an input signal vector X from an plurality of spatially separated transducers that detect energy from a plurality of sources including a target energy source and at least one non-target energy source. The filter receives and processes the input signal vector X to attenuate noise from non-target sources and provides an output signal vector Y. Tap weights WN for the filter are selected by first parameterizing each of the tap weights WN, such that each of the tap weights WN is characterized by a vector of parameters ?opt, and the solving for each parameter of the vector ?opt by minimizing the expected power of the array output signal Y. A robustness-control transformation is then applied to the vector p to provide a robust vector ?opt wherein the robustness-control transformation identifies and reduces target canceling components of the vector ?opt while preserving non-target canceling components.

Abstract: A method includes converting a received time domain digital signal to a corresponding frequency domain digital signal, calculating phase angles of tones of at least one symbol of the frequency domain digital signal when a symbol timing offset exists, and calculating at least one differential phase offset (DPO). A DPO is the difference between two consecutive gaps, a gap being the difference between the phase angle of a tone of the symbol of the frequency domain digital signal when the timing offset of the symbol exists and a correct phase angle of the tone of the symbol of the frequency domain digital signal. The method estimates the symbol timing offset with at least one DPO.

Abstract: A method of interleaving data for transmission is provided wherein first and second interleaving patterns for arranging data symbols in a source data stream into first and second transmitted data streams are selected. Each of said data symbols has at least one bit. The first and second transmitted data streams are transmitted substantially simultaneously on separate transmission channels to at least one receiver. The first and second patterns are used to transmit the data symbols in the source data stream in a different order on the respective transmission channels to maximize recovery of the source data stream when the transmission channels are blocked. The selected interleaving patterns can involve reordering the data symbols throughout the first and second transmitted data streams using different reordering criteria. The reordering criteria can vary on a frame-by-frame basis if the source data stream is time division multiplexed. Complementary data can be sent on respective transmission channels.

Abstract: Systems and methods for encoding fractional bit rates in a communication system, such as a pulse amplitude modulation (PAM) communication system, are provided. The systems and methods enable a first transceiver to specify to a second transceiver a desired fractional bit rate for transmitting data to the first transceiver. In this manner, the systems and methods of the present invention for the first time enable a single standardized specification of a generalized transmitter that may be used to implement any type of fractional encoding or mapping.

Abstract: A data transmission method that includes the steps of: a) performing two-dimensional interleaving along a time axis and along a frequency axis; b) transmitting the thus-obtained data by a multi-carrier transmission form; and c) producing, by channel copy operation, data which is short for the number of channels required for fast inverse Fourier transform performed antecedent and subsequent to step a).

Abstract: A system includes first unit, a processor and a transmitter. The processor is located in the first unit to generate data to be communicated to a second unit that is physically separated from the first unit. The transmitter includes an antenna, a first circuit and a push-pull amplifier. The first circuit generates signals that are indicative of the data, and the push-pull amplifier drives the antenna with a signal that is indicative of the data in response to the signals generated by the first circuit. The amplifier also establishes an output power from the amplifier to the antenna to less than about one hundred milliwatts.

Abstract: A wireless communication transmitter includes: an encoder (1) for encoding signals of information; a preamble signal portion (7) for storing a preamble signal of a known signal sequence; and an addition portion (5) for adding the preamble signal to the encoded signals of information and is characterized in that at least part of the preamble signal has periodicity of Tw/N (Tw: symbol length, N: an integer equal to 1 or greater) determined depending on the difference in the communication system of transmission.

Abstract: An improved OFDM receiver is disclosed that repositions peaks in an OFDM frame to a desired position away from the frame boundary to reduce the probability of timing ambiguity. Each OFDM frame is divided into at least two windows during an acquisition mode to identify the index within each window having the maximum correlation. The improved timing acquisition of the present invention permits the Fast Fourier Transform (FFT) operation to operate on the correctly aligned symbol for improved accuracy. In addition, the present invention provides improved mechanisms for declaring when timing is acquired or when timing has been lost. In one implementation, the peaks are shifted from the frame boundary to the center of the OFDM frame, thereby removing the ambiguity of whether a given peak is associated with a previous or subsequent frame.

Abstract: A method is provided for acquiring incoming signals in a wireless network device. This method uses three different types of preamble: a normal preamble, a short preamble, and a long preamble. One of these preambles will be used as a default preamble. Then, depending upon signal parameters, the device can change from one preamble to another, trading off data transmission speed and acquisition time to achieve the maximum data transmission speed by using the minimum acquisition time. These signal parameters could be signal strength, the number of packet retransmissions the device must request, or any other metric that is required. And thresholds will vary with the quality of service.

Abstract: A system includes a sampling circuit, an analog filter, an analog input, a modulator, and a modulating source. The modulating source includes an output that generates an impulse response encoded as a sigma-delta sequence. The output of the modulating source is coupled to the modulator, which is coupled to the analog input. The analog filter is coupled to the modulator and the sampling circuit. When the system is configured as a filter, an analog signal is modulated with the sigma-delta sequence. The modulated signal is filtered and then sampled.

Abstract: This invention provides techniques for a CDMA system having high spectrum efficiency with low transmit power. Each transmitter comprises means of selecting some core-sequences out of multiple sequences to make them convey plural data, means of producing an enveloped selected sequence with such a method as to arrange as guard sequences to a repeated sequence made by repeating each of the selected core-sequences, means of modulating a user specific orthogonal carrier frequency by the enveloped selected sequence to produce a transmit-symbol, and means of transmitting the transmit-symbols. And a receiver comprises means of demodulating a receive-symbol with one of the user specific carrier frequencies to produce a base-band receive-symbol, means of separating respective components corresponding to the sequences selected by the user, by analyzing the base-band receive-symbol with a matrix composed of a channel response vector from the user to the receiver to detect plural data on the components.

Abstract: A method of quadrature amplitude modulation involving encoding phase differentially and amplitude absolutely, allowing for a high data rate and spectral efficiency in data transmission and other communication applications, and allowing for amplitude scaling to facilitate data recovery; amplitude scale tracking to track-out rapid and severe scale variations and facilitate successful demodulation and data retrieval; 2N power carrier recovery; incoherent demodulation where coherent carrier recovery is not possible or practical due to signal degradation; coherent demodulation; multipath equalization to equalize frequency dependent multipath; and demodulation filtering.

Abstract: A method is provided for transmitting signals from a transmitter comprising two or more antennas in a mobile telecommunications network. The method involves determining channel state information, estimating the reliability of that channel state information, and space time block encoding at least one data sequence. Before transmitting the data sequence, a linear transformation is applied to the data sequence so as to at least partially compensate for channel variations. The linear transformation is dependent upon the channel state information and upon the estimated reliability of the channel state information.

Abstract: Tracking methods and systems for providing timing recovery of continuous signals is presented. According to one embodiment, the method includes: sampling a continuous signal; estimating a timing disturbance of the sampled continuous signal; generating a timing adjustment signal in accordance with the estimated timing disturbance; and adjusting a sampling signal associated with a sampling device based on the timing adjustment signal.