This invention teaches to the details of an interference suppressing receiver for suppressing intra-cell and inter-cell interference in coded, multiple-access, spread spectrum transmissions that propagate through frequency selective communication channels to a multiplicity of receive antennas. The receiver is designed or adapted through the repeated use of symbol-estimate weighting, subtractive suppression with a stabilizing step-size, and mixed-decision symbol estimates. Receiver embodiments may be designed, adapted, and implemented explicitly in software or programmed hardware, or implicitly in standard RAKE-based hardware either within the RAKE (i.e., at the finger level) or outside the RAKE (i.e., at the user or subchannel symbol level). Embodiments may be employed in user equipment on the forward link or in a base station on the reverse link. It may be adapted to general signal processing applications where a signal is to be extracted from interference.

A method for performing self-interference cancellation by a communication device which uses an FDR mode can comprise the steps of: measuring the strength of a residual self-interference signal, after antenna and analog self-interference cancellation, for each subband with respect to a predetermined number of subbands configured in a communication device; determining the order of a nonlinear self-interference signal component, to be considered for channel estimation of a nonlinear self-interference signal, for each subband on the basis of the strength of the residual self-interference signal that has been measured for each subband; and performing channel estimation of the nonlinear self-interference signal on the basis of the order that has been determined for each subband.

A method and apparatus determine parameters and conditions for line of sight MIMO communication. Reference signals can be received at a receiving device from a transmitting device. A channel matrix can be measured based on the reference signals. At least two of a first line of sight channel parameter, a second line of sight channel parameter, and a third line of sight channel parameter can be extracted based on the channel matrix. The first line of sight channel parameter can be based on transmitting device antenna element spacing. The second line of sight channel parameter can be based on a product of the transmitting device antenna element spacing and a receiving device antenna element spacing. The third line of sight channel parameter can be based on the receiving device antenna element spacing. The at least two line of sight channel parameters can be transmitted to the transmitting device.

The present invention provides a method and devices for transmitting and receiving a synchronization signal and a method for generating a synchronization signal in a wireless access system supporting NB-IoT. A method for transmitting a narrowband secondary synchronization signal (N-SSS) by a base station in a wireless access system supporting NB-IoT, according to an embodiment of the present invention, can comprise the steps of: generating a first sequence having a size M so as to generate an N-SSS; generating a second sequence having a size M so as to generate an N-SSS; generating an N-SSS by means of the first sequence and second sequence; and transmitting the N-SSS by means of n OFDM symbols. The size of a bandwidth used in the wireless access system supporting NB-IoT is the size of one physical resource block (PRB), and one PRB can comprise twelve subcarriers in a frequency domain.

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.

An echo detection circuit for a multi-carrier system includes a memory, a threshold generating circuit and an echo determining circuit. The memory stores a plurality of channel impulse response values of the multi-channel system. The channel impulse response values include a target channel impulse response value, a plurality of preceding channel impulse response values and a plurality of subsequent channel impulse response values; a threshold generating circuit, coupled to the memory, generating a threshold corresponding to the target channel impulse response according to the preceding channel impulse response values and the subsequent channel impulse response values; and an echo determining circuit, coupled to the threshold generating circuit and the memory, comparing the target channel impulse response value with the threshold to determine whether the target channel impulse response value corresponds to an echo path of the multi-carrier system.

A method uses an electromagnetic navigation system, including a number of field transmitters and at least one receiver. The method includes receiving a field signal from the at least one receiver, and the field signal includes a number of different frequencies corresponding to each of the field transmitters. The received field signal is multiplied by a synchronization signal using a frequency-division multiplexing scheme, and the received field signal is integrated over a predetermined sampling interval and converted into an integrated signal having only a desired signal based on the synchronization signal. The integrated signal is outputted for subsequent processing of the electromagnetic navigation system.

A method for estimating a nonlinear self-interference channel in a wireless channel system, according to the present invention, can further comprise the steps of: applying a first sequence to a first symbol; applying, to a second symbol, a sequence of which a phase is shifted from that of the first sequence by /2; and transmitting the first symbol and the second symbol.

Aspects of the subject disclosure may include, for example, a device, process or software that determines an operation between a number of pairs of antennas of a set of antennas. A pair of antennas of the number of pairs of antennas is determined based on the operation. One antenna of the pair of antennas is eliminated from the set of antennas, which results in a reduced number of antennas remaining in the set of antennas. Each of the determining of the operation, the determining of the pair of antennas of the reduced number of antennas and the eliminating of the one antenna of the pair of antennas is repeated in response to the reduced number of antennas being greater than a predetermined number of antennas. Other embodiments are disclosed.

The invention discloses a cyclic-Frequency shift orthogonal frequency division multiplex spread spectrum device, comprising: at least one communication device for performing the conversion between a series of bits and a frequency domain symbol out of a plurality of frequency combination patterns; wherein different patterns correspond to different bit values; and the device forms a cyclic frequency shift value utilizing a frequency reordering, each of the cyclic frequency shift values corresponding to a frequency combination pattern.