A method of detecting transient changes in the distribution of a discrete time series includes: operating in a sparse mode wherein, at sniff periods successively repeated at a first rate, at most K test phases are performed, K being an integer superior or equal to two, each test phase consisting of analyzing, by a sampling stopping time determination unit, samples of the time series captured by a sampler at sampling times according to a second rate which is higher than the first rate to provide a positive or negative result of the test phase. If the results of K successive test phases of a sniff period are each positive, the method switches to operate in a dense mode wherein the sampler is operated to continuously capture samples of the time series at sampling times according to the second sampling rate.

It is possible to improve the CQI reception performance even when a delay is caused in a propagation path, a transmission timing error is caused, or a residual interference is generated between cyclic shift amounts of different ZC sequences. For the second symbol and the sixth symbol of the ACK/NACK signal which are multiplexed by RS of CQI, (+, +) or (−, −) is applied to a partial sequence of the Walsh sequence. For RS of CQI transmitted from a mobile station, + is added as an RS phase of the second symbol and − is added as an RS phase of the sixth symbol. A base station (100) receives multiplexed signals of ACK/NACK signals and CQI signals transmitted from a plurality of mobile stations. An RS synthesis unit (119) performs synthesis by aligning the RS phase of CQI.

It is possible to improve the CQI reception performance even when a delay is caused in a propagation path, a transmission timing error is caused, or a residual interference is generated between cyclic shift amounts of different ZC sequences. For the second symbol and the sixth symbol of the ACK/NACK signal which are multiplexed by RS of CQI, (+, +) or (−, −) is applied to a partial sequence of the Walsh sequence. For RS of CQI transmitted from a mobile station, + is added as an RS phase of the second symbol and − is added as an RS phase of the sixth symbol. A base station (100) receives multiplexed signals of ACK/NACK signals and CQI signals transmitted from a plurality of mobile stations. An RS synthesis unit (119) performs synthesis by aligning the RS phase of CQI.

Method of reducing multipath effects on phase measurements, including receiving radio signals with different pseudo-random codes transmitted by at least four base stations, each at particular frequency received by one channel; measuring delay difference and phase difference from different pairs of base stations; calculating a current position of the receiver based on the measured phase differences and delay differences, wherein the base stations differ in pseudo-random codes at same frequencies or differ in carrier frequency or polarization type if using the same pseudo-random codes, and wherein a number of channels in the receiver exceeds a number of channels needed for the calculating of the current position; detecting anomalous jumps in phase of one or more channels, based on first or second derivative of the phase, as being indicative of multipath signal reception; removing those channels from calculation of current position; and calculating current position based on remaining channels.

A demodulation apparatus demodulates spectrum-spread received data, and includes a band variable filter removing noise components from despread received data, a power conversion unit converting each sample value of received data after removing noise components to a power value, a cyclic addition unit cyclically adding the power value in bit periods of received data, a maximum-value detection/average-level measurement unit detecting a maximum value from a cyclic-addition result of the cyclic addition unit, an estimation unit estimating a spreading-code timing and a carrier frequency based on maximum-value information detected by the maximum-value detection/average-level measurement unit, a spreading-code generation unit generating a spreading code with a timing according to an estimation result of a spreading-code timing obtained by the estimation unit, and a local-signal generation unit setting a local-signal frequency according to an estimation result of a carrier frequency obtained by the estimation unit.

A demodulation apparatus demodulates spectrum-spread received data, and includes a band variable filter removing noise components from despread received data, a power conversion unit converting each sample value of received data after removing noise components to a power value, a cyclic addition unit cyclically adding the power value in bit periods of received data, a maximum-value detection/average-level measurement unit detecting a maximum value from a cyclic-addition result of the cyclic addition unit, an estimation unit estimating a spreading-code timing and a carrier frequency based on maximum-value information detected by the maximum-value detection/average-level measurement unit, a spreading-code generation unit generating a spreading code with a timing according to an estimation result of a spreading-code timing obtained by the estimation unit, and a local-signal generation unit setting a local-signal frequency according to an estimation result of a carrier frequency obtained by the estimation unit.

A method of generating a BOC correlation function based on partial correlation functions, an apparatus for tracking a BOC signal, and a spread spectrum signal receiver system using the same are disclosed herein. The apparatus includes a frequency offset compensation unit, a local code generation unit, a mixer, a delay lock loop (DLL), a phase lock loop (PLL), and a data extraction unit. The frequency offset compensation unit outputs a compensated received signal with respect to a received signal. The local code generation unit generates a delay-compensated local code based on a code delay value. The mixer mixes the delay-compensated local code with the frequency offset-compensated received signal. The DLL repeatedly tracks and calculates a code delay value. The PLL repeatedly calculates a carrier frequency compensation value. The data extraction unit extracts spreading data from a mixture of the delay-compensated local code and the compensated received signal.

A UWB impulse receiver including an RF stage followed by a baseband processing stage. The baseband processing stage includes a Rake filter including a plurality of time fingers, each finger including an integrator of the baseband signal during an acquisition window, a control module, and a detection module estimating the received symbols from the integration results. During a synchronization phase, the control module drives respective positions of the acquisition windows associated with the different fingers, to scan at a reception interval, the RF stage only operating, in a course of the synchronization phase, during the plurality of acquisition windows.

A synchronization timing detector includes n correlators, a calculation unit, and a symbol timing estimating unit. The n correlators calculate and output correlation values, between a received signal oversampled m times for one symbol period and a known synchronization pattern, by shifting sample timings by m/n samples each, where m is a natural number, and n is a natural number that satisfies 3≤n≤m and is a divisor of m. The calculation unit generates n correlation value vectors by arranging the correlation values output from the n correlators on polar coordinates at intervals of an angle of 2π(n/m) radians, and adds the n correlation value vectors to calculate an angle of a resultant vector of the correlation value vectors. The symbol timing estimating unit estimates a symbol timing of the received signal based on the angle of the resultant vector calculated by the calculation unit.

A multi-radio border router for synchronizing communications of multiple border router radios is provided. For example, the border router includes a border router component connected to each of the plurality of border router radios. The border router component configured for selecting one of the plurality of border router radios as a master radio and assigning channel offset parameters for each of the plurality of border router radios. The master radio is configured for broadcasting synchronization beacons based on which the non-master radios synchronize their respective clocks with that of the master radio. After the synchronization, each of the border router radios communicates with endpoints associated therewith according to a channel hopping pattern modified by applying a channel offset determined based on the channel offset parameters assigned to the respective radio.