A system that incorporates the subject disclosure may perform, for example, a method for receiving interference information, identifying a plurality of interferers, approximating a location of the plurality of interferers, and adjusting an antenna pattern of an antenna. The method can include determining traffic loads and adjusting the antenna pattern according to the traffic loads. Other embodiments are disclosed.

Method and apparatus for interference mitigation utilizing antenna pattern adjustments

An adaptive notch filter (ANF) module selectively filters a received wideband communication signal to eliminate narrowband interference that lies within the frequency spectrum of the wideband communication signal. To determine the presence of narrowband interference, the ANF module scans various known narrowband channels that lie within the frequency spectrum of the wideband communication signal and determines signal strengths for each of the narrowband channels. The signal strengths from the narrowband channels are compared to a threshold that is derived from the narrowband signal strengths. Narrowband channels having signal strengths that are greater than the threshold are determined to have interference.

Interference detection, identification, extraction and reporting

An improved adaptive notch filter for removing undesired cochannel FM interference includes in-phase and quadrature signal processing paths in which the undesired FM signal is translated to zero frequency, i.e. to DC. In each of the in-phase and quadrature phase signal paths, a first multiplier translates the input frequency spectrum in a dynamic manner so that the frequency of the undesired FM signal is always centered on DC. The undesired signal, now at DC, is filtered out by a high pass filter with a sharp rolloff. The output of the high pass filter is remultiplied in a second multiplier to translate the desired FM signal back to the original position in the frequency spectrum. In order to eliminate an unwanted difference frequency remodulation signal at the output of the second multiplier, the quadrature phase signal path performs a parallel operation on the same input signal, but with a quadrature phase (90 degree phase shift) control signal. The output the in-phase and quadrature signal processing circuits are combined in an adder circuit to cancel the unwanted difference frequency remodulation signal.

Adaptive notch filter for FM interference cancellation

A receiver or receiver system for high speed data communications having a radio frequency noise canceller (112) is disclosed. The radio frequency noise canceller (112) removes radio-frequency noise from received signals over a transmission medium by adaptively estimating the radio-frequency noise during data transmission. In one embodiment, the radio frequency noise canceller includes: an adaptive filter (208) for producing a noise cancellation signal by filtering a reference noise signal based on filter parameters, a subtractor (202) for subtracting the noise cancellation signal from the first signal to produce the second signal; and an update circuit (204) for enabling, at predetermined times, modification of the parameters of the adaptive filter based on the then existing second signal. A method for removing radio frequency noise is also disclosed.

Radio frequency noise canceller

The output signal of a phase tracking system maintains phase coherence with the dominant input signal while tracking the frequency of that same dominant input signal without additional phase shifting circuitry Circuitry having a second phase locked loop is added to a conventional phase locked loop to form a phase tracking system which provides a precisely constant phase shift over a full range of frequencies of the signal captured by the conventional phase locked loop

Method and apparatus for frequency independent phase tracking of input signals in receiving systems and the like

A signal receiving system for receiving messages from each of several unequal amplitude FM carriers occupying the same portion of the frequency band. The signal receiving system receives power division multiplexed signals, each of which being allocated a portion of the total average power of an assigned FM band.

Glen A. Myers

Papers

Multiple reuse of an FM band