To facilitate positioning a user device, the user device is configured to measure, per an antenna array, reference signals received from transmission-reception points and to check, whether a downlink reference signal from a transmission-reception point is received in a serving antenna array and in one or more non-serving antenna arrays with a first delay. A non-serving antenna array receiving the signal with the first delay is an alternative antenna array to the serving antenna array. When the serving antenna array is under a maximum permissible exposure event, the user device is configured to select, which one of one or more alternative antenna arrays and the serving antenna panel is to be used for transmitting at least a positioning signal to the transmission-reception point.

A channel estimator, comprises: a receiver receives a first time-domain training sequence; a first convolution circuit generates an estimated value for the first time-domain training sequence by convoluting a second time-domain training sequence with a current channel estimation value; a first subtractor generates an error by subtracting the estimated value for the first time-domain training sequence from the value of the first time-domain training sequence; an updating circuit generates an updated channel estimation value by updating the current channel estimation value with the error; the receiver iteratively receives a next symbol of the first time-domain training sequence, the first convolution circuit, the subtractor and the updating circuit repeat their operation until completion of receipt of a last symbol of the first time-domain training sequence. The updating circuit outputs the current updated channel estimation value upon completion of receipt of a last first time-domain training sequence.

The present application describes systems and methods of performing self-interference cancellation. Such systems may include generating a transmit signal along a transmit path of a transceiver, where the transmit signal can be sent through a circulator to isolate the transmit signal from a receiver. The transmit signal may be transmitted from an antenna, and a signal may be reflected from the antenna, where the reflected signal may be at less power than an incident power to the antenna, and where the reflected signal may include a transmitter carrier signal and a transmitter noise. A received signal may be routed from the antenna to the receiver, the reflected signal may be routed through a filter and a phase shifter, and the signal may be combined with the received signal in the receive path to cancel the portion of the transmit signal that entered the receive path towards the receiver from the circulator.

A method in a receiver includes receiving a signal that traversed a multipath channel having a channel response, so as to produce a received sequence of samples that are indicative of the channel response. Using a predefined similarity measure, multiple metrics between the received sequence of samples and multiple respective candidate sequences of samples are calculated by the receiver. Each candidate sequence includes a combination of one or more dominant signal components having respective sample delays, and each candidate sequence corresponds to a channel multipath candidate that has one or more channel paths at the respective sample delays. The channel response is estimated by the receiver, by selecting the candidate sequence that best matches the received sequence, the selecting being based on the similarity measure.

A method to be performed at a station configured to connect to a Long Term Evolution radio access network (LTE-RAN) to utilize enhanced Multimedia Broadcast Multicast Services using a Multicast-Broadcast Single-Frequency Network (MBSFN). The method including receiving a MBSFN subframe having a MBSFN subframe structure including a plurality of Orthogonal Frequency-Division Multiplexing (OFDM) symbols, a first one of the OFDM symbols having a first reference symbol inserted therein, a second one of the OFDM symbols having a second reference symbol inserted therein, determining a rate of change of channel conditions being experienced by the station and performing a non-destaggered channel estimation when the rate of change of channel conditions is greater than a predetermined threshold, the non-destaggered channel estimation using a first Channel Impulse Response (CIR) at the first OFDM symbol and a second CIR at the second OFDM symbol.

A method for associating signal sources and paths includes determining secondary paths of a signal received at a reception point, wherein the signal reflects off one or more reflective surfaces before being received at the reception point, determining mirror sources of the secondary paths in accordance with locations of the one or more reflective surfaces and a main source of the signal, determining associations between the secondary paths and the mirror sources based on cross points at which the signal reflected off the one or more reflective surfaces, thereby obtaining path-source associations, and instructing use of the path-source associations in multi-source channel estimation.

A User Equipment in a wireless communication network includes a multiplicity of antennas, from which a subset of antennas is selected using a selection scheme synchronized to the network. A set of sub-carriers is selected from a plurality of sub-carriers using a selection scheme synchronized to the network. The UE receives a plurality of known reference symbols over the selected set of sub-carriers and through the selected subset of antennas. A frequency response for each selected sub-carrier is estimated over only the selected subset of antennas. The results are quantized and transmitted to the network on an uplink control channel.

A method for associating signal sources and paths includes determining secondary paths of a signal received at a reception point, wherein the signal reflects off one or more reflective surfaces before being received at the reception point, determining mirror sources of the secondary paths in accordance with locations of the one or more reflective surfaces and a main source of the signal, determining associations between the secondary paths and the mirror sources based on cross points at which the signal reflected off the one or more reflective surfaces, thereby obtaining path-source associations, and instructing use of the path-source associations in multi-source channel estimation.

A communication apparatus for correcting a situation of a spectrum inverted signal includes a channel estimation module and an equalization module. The channel estimation module determines a channel estimation parameter, and receives at least one frame signal to generate a convolution restored frame signal corresponding to the frame signal. The equalization module includes a first computation circuit and a second computation circuit. The first computation circuit receives the channel estimation parameter and the convolution restored frame signal to generate a transformation channel estimation parameter and a transformed convolution restored frame signal. The second computation circuit receives the transformed channel estimation parameter and the transformed convolution restored frame signal to generate an original frame signal corresponding to the frame signal. The first computation circuit further feeds back a transient original frame signal to the channel estimation module to update the channel estimation parameter.

The present application a digital self-interference residual cancellation method that adjusts a magnitude of a sampled transmit signal based on compared magnitude and phases associated with tones. The digital self-interference residual cancellation method may follow an analog carrier cancellation stage where the digital self-interference residual cancellation is based on a determination of the channel circuit response used to control an infinite impulse response filter which can compensate using both poles and zeroes.