Abstract: One embodiment relates to an apparatus for sample rate conversion. A sample rate converter is arranged to receive an input signal at an input sampling frequency and use an interpolation interval to convert the input signal to an output signal at an output sampling frequency. A rate controller is arranged to alternate between different frequency control words for use in generating the interpolation interval signal. Another embodiment relates to a method of sample rate conversion. Another embodiment relates to a rate controller circuit. Other embodiments, aspects, and features are also disclosed.

Abstract: Methods and apparatuses are provided for increasing the frequency resolution of a multi-channel QAM modulator and using a novel IDFT/IFFT and polyphase filter bank architecture to provide a more computationally efficient and high density multi-channel QAM modulator. The implementations of the improved multi-channel QAM modulator modulate QAM symbol streams onto respective carrier signals where the frequency of each carrier signal is an integer multiple of a fraction of the input sample rate of the respective QAM symbol stream. The modulated carriers are then combined using a novel IDFT/IFFT and polyphase filter bank architecture.

Abstract: One embodiment relates to an apparatus for sample rate conversion. A sample rate converter is arranged to receive an input signal at an input sampling frequency and use an interpolation interval to convert the input signal to an output signal at an output sampling frequency. A rate controller is arranged to alternate between different frequency control words for use in generating the interpolation interval signal. Another embodiment relates to a method of sample rate conversion. Another embodiment relates to a rate controller circuit. Other embodiments, aspects, and features are also disclosed.

Abstract: A method, wireless controller, and information processing system are provided to dynamically allocate spectrum sensing resources. A first input (804) including available sensing session time for performing spectrum sensing with respect to one or more primary systems (102) is received. A second input (806) including a set of communication channels to be monitored in the spectrum sensing session is received. A third input (808) including detection constraints associated with a plurality of available sensing nodes (114) in a secondary network (104) for performing the spectrum sensing is received. Spectrum sensing resources are dynamically allocated (814) among a set of the plurality of available sensing nodes (114) based on the first (804), second (806), and third inputs (808).

Abstract: Methods and apparatuses are provided for increasing the frequency resolution of a multi-channel QAM modulator and using a novel IDFT/IFFT and polyphase filter bank architecture to provide a more computationally efficient and high density multi-channel QAM modulator. The implementations of the improved multi-channel QAM modulator modulate QAM symbol streams onto respective carrier signals where the frequency of each carrier signal is an integer multiple of a fraction of the input sample rate of the respective QAM symbol stream. The modulated carriers are then combined using a novel IDFT/IFFT and polyphase filter bank architecture.

Abstract: A cognitive radio wireless device (114) dynamically manages signal detection in a cognitive radio system (100). Spectrum sensing is performed for a first sensing frame on at least one communication channel. At least one observed signal is received (204) on the at least one communication channel. A detection decision (210) is performed to determine if the observed signal is noise or an active signal associated with an active user. The detection decision (210) is performed by comparing observed signal energy estimation with a current detection threshold. The current detection threshold can be an arbitrarily defined threshold or a detection threshold based on a previous detection decision for a sensing frame immediately prior to the first sensing frame.

Abstract: A method for improving burst acquisition in a receiver includes receiving a signal, and performing a sync word search on the signal, wherein the sync word search includes performing a hybrid synchronization technique, the hybrid synchronization technique including both a lower order modulation (e.g., BPSK) detection and correlation process and a higher order modulation (e.g., QPSK) detection and correlation process.

Abstract: A cognitive radio wireless device (114) dynamically manages signal detection in a cognitive radio system (100). Spectrum sensing is performed for a first sensing frame on at least one communication channel. At least one observed signal is received (204) on the at least one communication channel. A detection decision (210) is performed to determine if the observed signal is noise or an active signal associated with an active user. The detection decision (210) is performed by comparing observed signal energy estimation with a current detection threshold. The current detection threshold can be an arbitrarily defined threshold or a detection threshold based on a previous detection decision for a sensing frame immediately prior to the first sensing frame.

Abstract: A method, wireless controller, and information processing system are provided to dynamically allocate spectrum sensing resources. A first input (804) including available sensing session time for performing spectrum sensing with respect to one or more primary systems (102) is received. A second input (806) including a set of communication channels to be monitored in the spectrum sensing session is received. A third input (808) including detection constraints associated with a plurality of available sensing nodes (114) in a secondary network (104) for performing the spectrum sensing is received. Spectrum sensing resources are dynamically allocated (814) among a set of the plurality of available sensing nodes (114) based on the first (804), second (806), and third inputs (808).

Abstract: A digital modulator having a sample rate converter that does not require that the final output sampling rate, FOUT, of the sample rate converter be at least twice as great as the input sampling rate, FIN, of the sample rate converter. The upsampling interpolation filter stages of the sample rate converter of the invention do not require any reference clocks to be provided by the NCO of the sample rate converter. Therefore, the upsampling interpolation filter stages are decoupled from the final output sampling rate, FOUT. The interpolation algorithms may be implemented in software, hardware, or a combination of software and hardware. In addition, the polynomial-based interpolator of the Farrow Structure of the invention is capable of using an even or odd number of basepoints.

Abstract: A method and system for generating a double-sided pulse width modulation (PWM) signal (110) is disclosed. The method includes generating a leading edge PWM signal and a trailing edge PWM signal from a pulse code modulation (PCM) data stream (102) using a modulation conversion circuitry (106). The method further includes combining the leading edge PWM signal and the trailing edge PWM signal to form a double-sided PWM signal using a combining circuitry (108).

Abstract: A digital modulator having a sample rate converter that does not require that the final output sampling rate, FOUT, of the sample rate converter be at least twice as great as the input sampling rate, FIN, of the sample rate converter. The upsampling interpolation filter stages of the sample rate converter of the invention do not require any reference clocks to be provided by the NCO of the sample rate converter. Therefore, the upsampling interpolation filter stages are decoupled from the final output sampling rate, FOUT. The interpolation algorithms may be implemented in software, hardware, or a combination of software and hardware. In addition, the polynomial-based interpolator of the Farrow Structure of the invention is capable of using an even or odd number of basepoints.

Abstract: A method for improving burst acquisition in a receiver includes receiving a signal, and performing a sync word search on the signal, wherein the sync word search includes performing a hybrid synchronization technique, the hybrid synchronization technique including both a lower order modulation (e.g., BPSK) detection and correlation process and a higher order modulation (e.g., QPSK) detection and correlation process.

Abstract: A low power programmable digital filter integrated circuit architecture has a programmable front end servicing up to 4 digital sources. Changing the programming of the front end permits digital outputs from different sensor types to be accommodated. Digital filtering is accomplished using a digital signal processor that is programmable to accommodate different decimation ratios. A serial data output register receives the filtered digital signals and provides them to an output port. The digital filter integrated circuit may be connected in a token passing configuration with other digital filter integrated circuits to increase the number of sources accommodated.

Abstract: A programmable correlator for a communication system includes an input queue coupled with an analog-to-digital converter (ADC). The input queue includes a random access memory (RAM) wherein sampled data streams from the ADC are written into the RAM. The input queue has two banks of memory of width 2M. A flexible complex correlator is operable on M samples. The correlator is coupled to read M complex samples out of 2M samples from the input queue. A pseudo-noise (PN) crossbar unit operates to rotate a generated PN code to match a rotation of the input queue data in the complex correlator.

Abstract: The invention provides a method for generating a code sequence. A code-generation instruction is received from memory. One or more control signals are determined based on the code-generation instruction. A code sequence is generated based on the control signals, a current state input, and a mask input.

Abstract: A programmable correlator for a communication system includes an input queue coupled with an analog-to-digital converter (ADC). The input queue includes a random access memory (RAM) wherein sampled data streams from the ADC are written into the RAM. The input queue has two banks of memory of width 2M. A flexible complex correlator is operable on M samples. The correlator is coupled to read M complex samples out of 2M samples from the input queue. A pseudo-noise (PN) crossbar unit operates to rotate a generated PN code to match a rotation of the input queue data in the complex correlator.

Abstract: The invention provides a method for generating a code sequence. A code-generation instruction is received from memory. One or more control signals are determined based on the code-generation instruction. A code sequence is generated based on the control signals, a current state input, and a mask input.

Abstract: One or more masks comprising pseudorandom sequence generating polynomials are utilized to derive new polynomials to thereby minimize the number of polynomials that need be stored to support use of pseudorandom sequences. The polynomials each correspond to a given state of a pseudorandom sequence and derivation of a particular such polynomial will allow calculation of the corresponding given state. A radio (85) in a code division multiple access wireless communications system (80) uses this approach to achieve rapid phase correlation with a pseudorandom sequence that is used by the system to facilitate synchronization.

Abstract: A low power programmable digital filter integrated circuit architecture has a programmable front end servicing up to 4 digital sources. Changing the programming of the front end permits digital outputs from different sensor types to be accommodated. Digital filtering is accomplished using a digital signal processor that is programmable to accommodate different decimation ratios. A serial data output register receives the filtered digital signals and provides them to an output port. The digital filter integrated circuit may be connected in a token passing configuration with other digital filter integrated circuits to increase the number of sources accommodated.