The present disclosure relates to signal transmission methods, apparatuses, and systems. One example method includes sending a narrow band signal to a receive end, where the narrow band signal is used by the receive end to determine initial time-frequency synchronization information, and sending an ultra-wideband signal to the receive end, where the ultra-wideband signal includes a channel impulse response training sequence (CTS) field, the CTS field is used by the receive end to determine a channel impulse response, the CTS field includes at least one CTS symbol, and the CTS symbol includes at least one first preamble symbol or is generated by spreading at least one first preamble symbol.

An apparatus and method for transmitting digital broadcast signal are provided. The apparatus includes a group formatter to format a data group including mobile service data, where the group formatter further maps the mobile service data into a data group of interleaved format, adds N training sequences into a corresponding location of the data group of interleaved format, adds signaling data into the data group of interleaved format, inserts place holder bytes for MPEG header and non-systematic Reed-Solomon (RS) parity into the data group of interleaved format, and deinterleaves the mobile service data in the data group of interleaved format, a non-systematic RS encoder to non-systematic RS encode the mobile service data in the formatted data group and insert non-systematic RS parity obtained from the non-systematic RS encoding into the formatted data group.

Methods and apparatus of channel estimation using time-domain parameter extraction are disclosed. The wireless channel can be modeled by a multipath model with a limited number of parameters in the continuous time domain. In the discrete time domain, the multipath model leads to channel impulse responses that have a limited number of channel taps with non-negligible energy. Extracting the time-domain parameters and then reconstructing the channel yields channel estimates that have better accuracy. Time-domain parameter extraction also has lower computational complexity than existing methods.

A device for eliminating a channel effect is provided. A time-domain channel estimating unit generates a channel estimation result according to a first reference signal. A fast Fourier transform (FFT) unit performs FFT on the channel estimation result to generate a plurality of channel frequency responses corresponding to a plurality of frequency indices. An adjusting unit receives a plurality of input signals, and determines whether to adjust the input signal of each of the frequency indices according to the amplitude of the channel frequency response of each of the frequency indices to generate a set of adjusted signals. An inverse fast Fourier transform (IFFT) unit performs IFFT on a set of output signals associated with the set of adjusted signals to generate a feedback signal. The time-domain channel estimating unit further generates another channel estimation result according to a second reference signal and the feedback signal.

A receiver receives signals and noise over a frequency spectrum of a desired received signal. The desired received signal is spread using code division multiple access. The received signals and noise are demodulated to produce a demodulated signal. The demodulated signal is despread using a code uncorrelated with a code associated with the desired received signal. A power level of the despread demodulated signal is measured as an estimate of the noise level of the frequency spectrum.

The present application describes a computer-implemented method for configuring a front end including sweeping a first tone through the frequency band of the receive channel; receiving a first signal and a second signal containing interference; characterizing the receive channel using the first tone; processing the compensated first signal using an infinite impulse response filter based on the characterized receive channel to generate an interference cancelling signal; and coupling the interference cancelling signal to the second signal to generate an interference cancelled receive signal.

A wireless receiver receives location pilots embedded in received symbols and uses the location pilots to detect the first path for every base station the network has designated for the receiver to use in time of arrival estimation. The receiver preferably applies matching pursuit strategies to offer a robust and reliable identification of a channel impulse response's first path. The receiver may also receive and use estimation pilots as a supplement to the location pilot information in determining time of arrival. The receiver can use metrics characteristic of the channel to improve the robustness and reliability of the identification of a CIR's first path. With the first path identified, the receiver measures the time of arrival for signals from that path and the receiver determines the observed time difference of arrival (OTDOA) to respond to network requests for OTDOA and position determination measurements.

There is provided a computer-implemented method of estimating transmitted signals in a communication system, the signals being transmitted by a transmitter to a receiver over a communication channel having a channel response, the method comprising estimating the transmitted signals based on generated trial sequences minimizing the channel response between adjacent received signals. There is also provided a receiver, a signal detector device and a communication system adapted to estimated transmitted signals in a communication system by generating trial sequences and determining the generated trial sequences minimizing the channel response between adjacent received signals. The present invention is particularly adapted for OFDM communication systems.

A system and method for measuring characteristics of a signal transmission channel. A generator generates a defined signal as a function of user defined reference parameters, and injects the defined signal into an input of the signal transmission channel. An analyzer receives the defined signal from an output of the signal transmission channel. The analyzer also includes the user defined reference parameters, and measures a reference delay and reference frequency offset without any timing or phase reference synchronization with the generator. The analyzer computes a time-dependent (impulse response) and/or frequency-dependent (frequency response) variation of a response of the signal transmission channel relative to the reference delay and reference frequency offset.

An RF device includes a first channel with a first frequency band, configured to receive a first signal; and a second channel with a second frequency band, configured to receive a second signal. The first frequency band and the second frequency band are different. The device includes control circuitry configured to obtain a first channel response associated with the received first signal at the first channel, to obtain a second channel response associated with the received second signal at the second channel and to calibrate the first channel response and the second channel response by steering to a calibration base. The control circuitry is further configured to calibrate the first channel response and second channel response by channel stitching to obtain a combined channel response.