Disclosed herein are system, apparatus, article of manufacture, method and/or computer program product embodiments, and/or combinations and sub-combinations thereof, for synchronizing playback of audiovisual content with a dumb speaker. In some embodiments, a display device transmits a spread spectrum signal to a dumb speaker over a data channel using a spread spectrum code. The display device then receives the spread spectrum signal from the dumb speaker over an audio data channel. The display device despreads the spread spectrum signal based on the spreading code. The display device determines a time of receipt of the spread spectrum signal. The display device calculates an audiovisual output path delay for the dumb speaker based on the time of receipt and a time of transmission. The display device then synchronizes the playback of the audiovisual content at the dumb speaker and a smart speaker based on the audiovisual output path delay.

Disclosed herein are system, apparatus, article of manufacture, method and/or computer program product embodiments, and/or combinations and sub-combinations thereof, for synchronizing playback of audiovisual content among multiple speakers. In some embodiments, a first smart speaker receives a spread spectrum signal from a second smart speaker over an audio data channel. The first smart speaker despreads the spread spectrum signal based on a spreading code. The first smart speaker determines a time of receipt of the spread spectrum signal based on the despreading. The first smart speaker receives a time of transmission of the spread spectrum signal. The first smart speaker then calculates a playback delay based on the time of receipt and the time of transmission. Then the first smart speaker controls the playback of the audiovisual content based on the playback delay.

A system that incorporates aspects of the subject disclosure may perform operations including, for example, receiving, via an antenna, a signal generated by a communication device, detecting passive intermodulation interference in the signal, the interference generated by one or more transmitters unassociated with the communication device, and the interference determined from signal characteristics associated with a signaling protocol used by the one or more transmitters. Other embodiments are disclosed.

A method of synchronising a communication signal entering into a receiver. Each frame of the signal includes a learning symbol formed of N repetitions of a learning sequence. The method includes the determination of a total correlation signal by correlating the input signal with a correlation symbol formed of N repetitions of a correlation sequence corresponding to all or part of the learning sequence and duration t.sub.sc, and the determination of a partial correlation signal by correlating the input signal with the correlation sequence. A peak of the total correlation signal is identified at an instant t.sub.pct. At least one threshold is defined from the power of the peak of the total correlation signal, and the power of the partial correlation signal is compared here to the instants t.sub.pctk*t.sub.sc, with k a whole number between 0 and N1.

A method of synchronising a communication signal entering into a receiver. Each frame of the signal includes a learning symbol formed of N repetitions of a learning sequence. The method includes the determination of a total correlation signal by correlating the input signal with a correlation symbol formed of N repetitions of a correlation sequence corresponding to all or part of the learning sequence and duration t.sub.sc, and the determination of a partial correlation signal by correlating the input signal with the correlation sequence. A peak of the total correlation signal is identified at an instant t.sub.pct. At least one threshold is defined from the power of the peak of the total correlation signal, and the power of the partial correlation signal is compared here to the instants t.sub.pctk*t.sub.sc, with k a whole number between 0 and N1.

A receiver includes: a correlation value calculation unit calculating a first cross-correlation function between a received signal, having a preamble spread with an up chirp and a down chirp, and the up chirp and calculating a second cross-correlation function between the received signal and the down chirp; a power value calculation unit calculating first and second power values of the first and second cross-correlation functions; a correlation power memory storing the first and second power values at each sample timing for one period of a spread code; a threshold determination unit determining first and second estimated timings from the first and second power values for one period of the spread code, respectively; and an estimation unit estimating a spread code timing of a transmitter using the first and second estimated timings, and performing coarse estimation of a frequency offset with respect to the transmitter.

Embodiments of the present invention provide a data transmission method and a data transmission device. The data transmission device includes: a detection unit, configured to detect a first signal in a first cell; a determining unit, configured to determine a reference time point according to a first sequence of the detected first signal, where the reference time point is located in a first subframe of the first cell; where the determining unit is further configured to determine a position of a data channel according to the determined reference time point; and a receiving unit, configured to receive, according to the position of the data channel, control data and/or service data carried on the data channel. According to the embodiments of the present invention, resource utilization can be improved.

Embodiments of the present invention provide a data transmission method and a data transmission device. The data transmission device includes: a detection unit, configured to detect a first signal in a first cell; a determining unit, configured to determine a reference time point according to a first sequence of the detected first signal, where the reference time point is located in a first subframe of the first cell; where the determining unit is further configured to determine a position of a data channel according to the determined reference time point; and a receiving unit, configured to receive, according to the position of the data channel, control data and/or service data carried on the data channel. According to the embodiments of the present invention, resource utilization can be improved.

According to a signal transmitting method, a signal receiving method, and a related device and system, a generated single-wavelength optical carrier may be split into N subcarriers with a same wavelength by using a splitting device, corresponding data modulation and corresponding amplitude spread spectrum modulation are performed on the N subcarriers by using N spreading codes and N low-speed data signals obtained by deserializing a received high-speed data signal, to obtain N spread spectrum modulation signals, and the N spread spectrum modulation signals are combined and output. A multicarrier generation apparatus or the like having a relatively complex structure does not need to be used for optical carrier splitting, and spectrum spreading does not need to be performed in a phase modulation manner in which a plurality of delay units or controllable phase units are required.

According to a signal transmitting method, a signal receiving method, and a related device and system, a generated single-wavelength optical carrier may be split into N subcarriers with a same wavelength by using a splitting device, corresponding data modulation and corresponding amplitude spread spectrum modulation are performed on the N subcarriers by using N spreading codes and N low-speed data signals obtained by deserializing a received high-speed data signal, to obtain N spread spectrum modulation signals, and the N spread spectrum modulation signals are combined and output. A multicarrier generation apparatus or the like having a relatively complex structure does not need to be used for optical carrier splitting, and spectrum spreading does not need to be performed in a phase modulation manner in which a plurality of delay units or controllable phase units are required.