A method for channel estimation, performed by a wireless transmit/receive unit (WTRU), includes: receiving a plurality of input signals, generating a plurality of sensing matrices for the input signals, generating an augmented sensing matrix and an augmented observation vector according to the sensing matrices and the input signals, estimating a plurality of channel delay parameters according to the augmented sensing matrix and the augmented observation vector, and estimating channel information according to the channel delay parameters.

Systems and methods are disclosed for constrained receiver parameter optimization. Two parameter optimization functions may be applied, with one function providing constraints on the results of the second function in order to determine a parameter set to apply in the receiver. A method may comprise determining a first parameter set based on a first function, determining a second parameter set based on a second function different from the first function, and determining a third parameter set by using the first parameter set to define a subset of a parameter space to which to limit values from the second parameter set. In certain embodiments, a least squares function may be used to constrain the results of a general cost function.

A distributed radio access network (RAN) is provided. A selected wireless transceiver node(s) in a selected coverage cell receives a radio frequency (RF) test signal(s). The selected wireless transceiver node(s) determines an effective gain value based on a predefined characteristic of the RF test signal(s). The selected wireless transceiver node(s) communicates the effective gain value and other related parameters to a server apparatus in the distributed RAN. The server apparatus determines a common gain value for the selected wireless transceiver node(s) in the selected coverage cell based on the parameters. Accordingly, the selected wireless transceiver node(s) operates based on the common gain value. By determining a respective common gain value for each of the coverage cells in the distributed RAN, it may be possible for all the wireless transceiver nodes in the distributed RAN to communicate an uplink digital communications signal(s) without causing distortion in the uplink digital communications signal(s).

Disclosed is an electronic device, including a housing, a first communication circuit disposed in the housing and configured to support omnidirectional wireless communication, a second communication circuit disposed in the housing and configured to support directional wireless communication using beamforming, a processor disposed in the housing and operatively coupled to the first communication circuit and the second communication circuit, and a memory disposed in the housing and operatively coupled to the processor. The processor may be configured to receive at least one first radio signal through a communication channel from an external device capable of supporting the omnidirectional wireless communication and the directional wireless communication using the first communication circuit, determine a state of the communication channel based on at least part of the at least one first radio signal, and activate the second communication circuit based on at least part of the determined state of the communication channel wherein the second communication circuit is configured to receive a second radio signal from the external device.

A communication system that minimizes the transmission of pilot symbols while ensuring real-time channel tracking and symbol detection. The system employs a multiple-input multiple-output (MIMO) transmitter-receiver pair where there are many more receive antennas than transmit antennas. Communication occurs over a wide band RF channel via orthogonal frequency division multiplexing (OFDM) that employs a large number of sub-carriers.

Digital serializer/deserializer circuitry includes a data path and a date eye monitoring path. The data path includes a first analog-to-digital converter (ADC) to sample incoming data at a first rate, first digital filter circuitry to filter output of the first ADC, and a data slicer coupled to output of the first digital filter circuitry to output data above a threshold. The monitoring path includes a second ADC to sample the incoming data at a second rate lower than the first rate and to take samples at varying points along the incoming data waveform, second digital filter circuitry to filter output of the second ADC, and another data slicer coupled to output of the second digital filter circuitry to output data above an adjustable threshold and to sweep through varying threshold values. Error rate circuitry compares outputs of the data slicers to determine a data eye error rate.

A distributed radio access network (RAN) is provided. A selected wireless transceiver node(s) in a selected coverage cell receives a radio frequency (RF) test signal(s). The selected wireless transceiver node(s) determines an effective gain value based on a predefined characteristic of the RF test signal(s). The selected wireless transceiver node(s) communicates the effective gain value and other related parameters to a server apparatus in the distributed RAN. The server apparatus determines a common gain value for the selected wireless transceiver node(s) in the selected coverage cell based on the parameters. Accordingly, the selected wireless transceiver node(s) operates based on the common gain value. By determining a respective common gain value for each of the coverage cells in the distributed RAN, it may be possible for all the wireless transceiver nodes in the distributed RAN to communicate an uplink digital communications signal(s) without causing distortion in the uplink digital communications signal(s).

Disclosed is an electronic device, including a housing, a first communication circuit disposed in the housing and configured to support omnidirectional wireless communication, a second communication circuit disposed in the housing and configured to support directional wireless communication using beamforming, a processor disposed in the housing and operatively coupled to the first communication circuit and the second communication circuit, and a memory disposed in the housing and operatively coupled to the processor. The processor may be configured to receive at least one first radio signal through a communication channel from an external device capable of supporting the omnidirectional wireless communication and the directional wireless communication using the first communication circuit, determine a state of the communication channel based on at least part of the at least one first radio signal, and activate the second communication circuit based on at least part of the determined state of the communication channel wherein the second communication circuit is configured to receive a second radio signal from the external device.

A method for channel estimation, performed by a wireless transmit/receive unit (WTRU), includes: receiving a plurality of input signals, generating a plurality of sensing matrices for the input signals, generating an augmented sensing matrix and an augmented observation vector according to the sensing matrices and the input signals, estimating a plurality of channel delay parameters according to the augmented sensing matrix and the augmented observation vector, and estimating channel information according to the channel delay parameters.

Disclosed is a signal source estimation method and apparatus performing the same, the signal source estimation method including acquiring first reception signals received by first receivers, among signals radiated from signal sources, selecting second receivers receiving reception signals to be used to estimate the signal sources, from among the first receivers based on the first reception signals, and detecting the number of signal sources based on second reception signals received by the second receivers.