Abstract: A method and system for direct mode operation (DMO) of a talkgroup enables device to device (D2D) DMO operation leveraged from a Land Mobile Radio (LMR) system. The method includes scanning at a radio receiver a defined radio frequency spectrum; receiving at the radio receiver in the defined radio frequency spectrum a wake-up signal; identifying a talkgroup identifier in the wake-up signal, wherein the talkgroup identifier corresponds to a talkgroup being monitored by the radio receiver; in response to identifying the talkgroup identifier, decoding code sequences included in the wake-up signal; identifying in at least one of the code sequences both a center frequency and a transmission bandwidth of the DMO transmission; and tuning the radio receiver to receive the DMO transmission at the center frequency and transmission bandwidth.

Abstract: A method and apparatus for using erasure to improve signal decoding when data is impacted by an interference event. Embodiments may include receiving in an RF receiver a desired on-channel signal that includes an information signal modulated on to the desired on-channel signal; generating a sampled received signal with an analog-to-digital (A/D) converter; detecting an interference event using an interference detector as well as generating a mask based on the interference event; processing the sampled received signal using the mask to generate decoding data for use by a soft decoder; and, providing the decoding data to the soft decoder.

Abstract: A wideband phase detector configured to receive an intermediate frequency (IF) signal having a plurality of information signals at predetermined carrier frequencies and to generate a carrier indication signal used to control one or more attenuators to equalize the signal levels of the information signals thereby enabling a multichannel receiver to process the two information signals in a parallel fashion using a common analog front-end and analog to digital conversion circuit. The circuit may include an attenuation controller configured to provide control signals to the one or more attenuators to attenuate one or more corresponding information signals based on an average of the carrier indication signal.

Abstract: A method and apparatus for a receiver system in a receiver that includes at least two front end branches, each branch having its own intermediate frequency (IF) mixer to shift a received signal to an IF. When receiving multiple independent signals, the signals are digitized and the receiver performs a digital complex transform on each signal to obtain the corresponding quadrature component. When receiving a single signal the signal is routed to two mixers that are 90 degrees out of phase to obtain the quadrature signal components in the analog section of the receiver.

Abstract: A receiver for a wireless communication device provides a dual path receiver receiving first and second protocol-agnostic, uncorrelated receive signals simultaneously. The dual path receiver generating first and second offset IF signals from the simultaneously received first and second protocol-agnostic, uncorrelated receive signals. The receiver utilizes at least one converter for converting the first and second offset IF signals into at least one serial synchronous interface (SSI) signal representing the spectrum at IF. At least one processor receives the at least one SSI signal and applies parallel processing paths to demodulate the at least one SSI signal into separate baseband signals. The processor provides interference detection of, and level control for, the first and second offset IF signals.

Abstract: A method and apparatus for using erasure to improve signal decoding when data is impacted by an interference event. Embodiments may include receiving in an RF receiver a desired on-channel signal that includes an information signal modulated on to the desired on-channel signal; generating a sampled received signal with an analog-to-digital (A/D) converter; detecting an interference event using an interference detector as well as generating a mask based on the interference event; processing the sampled received signal using the mask to generate decoding data for use by a soft decoder; and, providing the decoding data to the soft decoder.

Abstract: A method and apparatus for a receiver system in a receiver that includes at least two front end branches, each branch having its own intermediate frequency (IF) mixer to shift a received signal to an IF. When receiving multiple independent signals, the signals are digitized and the receiver performs a digital complex transform on each signal to obtain the corresponding quadrature component. When receiving a single signal the signal is routed to two mixers that are 90 degrees out of phase to obtain the quadrature signal components in the analog section of the receiver.

Abstract: A wideband phase detector configured to receive an intermediate frequency (IF) signal having a plurality of information signals at predetermined carrier frequencies and to generate a carrier indication signal used to control one or more attenuators to equalize the signal levels of the information signals thereby enabling a multichannel receiver to process the two information signals in a parallel fashion using a common analog front-end and analog to digital conversion circuit. The circuit may include an attenuation controller configured to provide control signals to the one or more attenuators to attenuate one or more corresponding information signals based on an average of the carrier indication signal.

Abstract: A method for transmitting a communication generated by an originating device to a target device using a repeating device is provided. In the method the communication is transmitted from the originating device and received at the repeating device. A repeater request sequence is transmitted from the originating device and retransmitted from the first repeating device to the target device before the repeater request sequence is received at the first repeating device.

Abstract: A receiver for a wireless communication device provides a dual path receiver receiving first and second protocol-agnostic, uncorrelated receive signals simultaneously. The dual path receiver generating first and second offset IF signals from the simultaneously received first and second protocol-agnostic, uncorrelated receive signals. The receiver utilizes at least one converter for converting the first and second offset IF signals into at least one serial synchronous interface (SSI) signal representing the spectrum at IF. At least one processor receives the at least one SSI signal and applies parallel processing paths to demodulate the at least one SSI signal into separate baseband signals. The processor provides interference detection of, and level control for, the first and second offset IF signals.

Abstract: An apparatus and method for demodulating an FM RF signal is presented. An Adaptive Differentiate Cross Multiply (ADCM) system in which the energy estimate of the desired on-channel RF is generated using adaptive filtering. The adaptive filter includes low pass filtering of the instantaneous energy estimate. The bandwidth of the LPF is adjusted in real time based on the received signal strength energy estimate, the periodicity of any changes in the energy estimate, AGC setting for the receiver, and/or the type of sub-audible signaling applied to the RF signal if known. After the bandwidth is set, the optimum filtered energy estimate is applied to the system to demodulate the received information free from distortion artifacts associated with IQ imbalance. A normalized signal in the ADCM system is clipped by a limiter whose clipping threshold is equal to a maximum gain of differentiators in the ADCM system.

Abstract: A method for minimizing undesired signal coupling from digital interface between peripherals is presented. The method includes transmitting over the interface first and second signals having a parameter ?k set by a dynamic sequencer respectively to a first and second value ?1 and ?2, receiving the first and second signal and generating a first and second interference metric respectively for the first and second signal. The first and second interference metrics are correlated to generate a final parameter value ?f, and a transmitter is then configured to transmit a third signal over the interface with the final parameter value ?f.

Abstract: An apparatus and method for receiving and processing multiple independent, uncorrelated RF signals is presented. The apparatus includes a Hybrid-Direct Conversion Receiver incorporating front end branches, protocol-specific digital processing branches, an interference detector, a correlator, and an offset control for controlling oscillator sources. The front end branches each contain a preselector that filters received signals and a mixer that down converts the received signal to an IF offset from a reference frequency by a unique offset. The bandwidth of an IF processor is partitioned into sub-channels corresponding to the different offsets and is wider than the combination of the sub-channels. The interference detector and correlator determine whether a particular desired signal is degraded by interference signals and select a new sub-channel. This information is provided to the offset control, which adjusts a LO source coupled to the corresponding down mixer accordingly.

Abstract: Methods of enabling late entry into an on-going spread spectrum call are described. A late join frame replaces, and has the same size as, a traffic frame. A late join slot in the late join frame contains sufficient information in preamble and sync subframes to permit a target to join the call. The traffic slots in the late join frame replicate data such that call quality of the call is substantially unaffected if one of the remaining traffic frames is not received. The preamble and sync subframes frequencies may be the same as, or different from, preamble and sync frames frequencies during a call establishment phase of the call. If different, the preamble and sync subframes frequencies are selected from one or more frequencies. Use of the preamble and sync subframes frequencies is compensated for when selecting the traffic slot frequencies to obtain uniform utilization of the spectrum.

Abstract: A method of detecting an on-channel signal and synchronizing signal detection with correcting for DC offset errors in a direct conversion receiver is presented. A received signal is digitized, and a state machine operates to detect the presence of an on-channel signal. If the signal is not detected, a mixed mode training sequence is initiated in which the DC offset errors in both an analog and digital received signal path are corrected. While training, processing of the digitized samples by a digital signal processor and a host controller is suspended (while they are put into battery save mode) and the gain provided to subsequently received signals is minimized. The DC offset correction circuitry is bypassed and put into battery save mode at predetermined periods when DC offset correction is not performed.

Abstract: A method for transmitting a communication generated by an originating device to a target device using a repeating device is provided. In the method the communication is transmitted from the originating device and received at the repeating device. A repeater request sequence is transmitted from the originating device and retransmitted from the first repeating device to the target device before the repeater request sequence is received at the first repeating device.

Abstract: Methods of enabling late entry into an on-going spread spectrum call are described. A late join frame replaces, and has the same size as, a traffic frame. A late join slot in the late join frame contains sufficient information in preamble and sync subframes to permit a target to join the call. The traffic slots in the late join frame replicate data such that call quality of the call is substantially unaffected if one of the remaining traffic frames is not received. The preamble and sync subframes frequencies may be the same as, or different from, preamble and sync frames frequencies during a call establishment phase of the call. If different, the preamble and sync subframes frequencies are selected from one or more frequencies. Use of the preamble and sync subframes frequencies is compensated for when selecting the traffic slot frequencies to obtain uniform utilization of the spectrum.

Abstract: An apparatus and method for receiving and processing multiple independent, uncorrelated RF signals is presented. The apparatus includes a Hybrid-Direct Conversion Receiver incorporating front end branches, protocol-specific digital processing branches, an interference detector, a correlator, and an offset control for controlling oscillator sources. The front end branches each contain a preselector that filters received signals and a mixer that down converts the received signal to an IF offset from a reference frequency by a unique offset. The bandwidth of an IF processor is partitioned into sub-channels corresponding to the different offsets and is wider than the combination of the sub-channels. The interference detector and correlator determine whether a particular desired signal is degraded by interference signals and select a new sub-channel. This information is provided to the offset control, which adjusts a LO source coupled to the corresponding down mixer accordingly.

Abstract: A frequency generation unit (FGU) in a communication device includes a voltage controlled oscillator (VCO), an adjustable filter having a capacitive element for wideband operation, a current source with variable gain, and chirp generation control circuitry (CGC) that is used to generate location signals. The FGU receives, from a reference device, at least one location signal control parameter that defines linear frequency slope characteristics for a location signal. The CGC configures, based on the at least one location signal control parameter, the gain and a polarity of the current source to generate a first current during a first time period for charging the capacitive element to generate a control signal that is coupled to the VCO to generate a first part of the location signal having the defined linear frequency slope characteristics, wherein the first part of the location signal is transmitted using a transceiver of the communication device.

Abstract: A method (1100, 1200) of generating a composite mitigation signal (216, 902, 1002) is presented. The composite mitigation signal includes an odd integer (N) of transitions (310, 312) between a first amplitude and a second amplitude of the composite mitigation signal. Successive sets of the transition bursts are separated by a desired phase delay or time delay (330), or such separations are defined by a base signal (416) having a frequency equal to a fundamental frequency of the composite mitigation signal. The composite signal generators (222, 900, 1000) that generate the composite mitigation signal are also presented.