Abstract: Embodiments include processes, systems, and devices for reshaping virtual baseband signals for transmission on non-contiguous and variable portions of a physical baseband, such as a white space frequency band. In the transmission path, a spectrum virtualization layer maps a plurality of transmission components associated with a transmission symbol produced by a physical layer protocol to sub-carriers of the allocated physical frequency band. The spectrum virtualization layer then outputs a physical transmission symbol composed of time-domain samples derived from the mapped frequency components and a cyclic prefix. In the receive path, a time-domain symbol received on the physical baseband is reshaped and equalized by the virtual spectrum layer in order to recompose a time-domain samples of a transmission stream in the virtual baseband.

Abstract: Method and apparatuses are disclosed to substantially compensate for various unwanted interferences and/or distortions within a communications receiver. Each of these apparatuses and methods estimate the various unwanted interferences and/or distortions within the communications receiver. Each of these apparatuses and methods remove the estimates of the various unwanted interferences and/or distortions within the communications receiver from one or more communications signals within the communications receiver to substantially compensate for the various unwanted interferences and/or distortions.

Abstract: Methods and systems for handing off a wireless client between access points wherein the scanning for access points is decoupled from the handing off, thus reducing the delay in handing off. Channel scan delay may be eliminated or reduced in some embodiments by scanning early (prior to actual handoff) and interleaving the channel scan with ongoing traffic in a non-intrusive way. A smart handoff trigger may be used in some embodiments that covers both uplink and downlink quality, and addresses link asymmetry problems. The methods or systems may be implemented in some embodiments in a software-only client-only solution without the need to modify the networks themselves or their access points.

Abstract: Embodiments include processes, systems, and devices that allow a white space base station to request available frequency ranges for white space transmission in a local area. A white space finder service models a primary user device's transmission signal propagation area using terrain data associated with the local area of the primary user device. The white space finder service also determines, based on the location of the white space base station and the modeled propagation area, one or more locally available, non-interfering frequency ranges and provides them to the white space base station. The white space base station compares the provided frequency ranges to policies and selects one or more of the available frequencies that accommodate the policies. The white space base station also maps the transmission frequency ranges to virtual frequency ranges for transmission by a software-defined radio employing spectrum virtualization.

Abstract: A cooperative phase tracking system allows access points of a wireless network (e.g., a WiFi network) to use a clock or oscillator that may be different or independent from other access points of the same wireless network. As such, the cooperative phase tracking system eliminates a limitation of using a same clock (or oscillator) among the access points and at the same time may allow more access points to be installed for an associated wireless network to serve a larger area. Moreover, the cooperative phase tracking system may attribute intensive computations of relative phase drifts associated with the access points to a dedicated coordinator, thereby alleviating workload of the access points of the wireless network.

Abstract: An extended wireless access point may have many distributed radio units connected to associated processing units via a radio transmission network comprising commodity switches controlled by one or more network controllers. The one or more network controllers may use a load balancing algorithm to select a processing unit to process a signal received by a distributed radio unit. The radio units may receive a wireless signal, and generate compressed samples of the wireless signal for transport via the radio transmission network and processing by a selected processing unit. Similarly, a processing unit may generate and transmit via the radio transmission network compressed samples for decompression and transmission by a radio unit.

Abstract: Method and apparatuses are disclosed to substantially compensate for various unwanted interferences and/or distortions within a communications receiver. Each of these apparatuses and methods estimate the various unwanted interferences and/or distortions within the communications receiver. Each of these apparatuses and methods remove the estimates of the various unwanted interferences and/or distortions within the communications receiver from one or more communications signals within the communications receiver to substantially compensate for the various unwanted interferences and/or distortions.

Abstract: Method and apparatuses are disclosed to substantially compensate for various unwanted interferences and/or distortions within a communications receiver. Each of these apparatuses and methods estimate the various unwanted interferences and/or distortions within the communications receiver. Each of these apparatuses and methods remove the estimates of the various unwanted interferences and/or distortions within the communications receiver from one or more communications signals within the communications receiver to substantially compensate for the various unwanted interferences and/or distortions.

Abstract: Techniques and systems that improve throughput between a pair of nodes by using two multi-hop paths of one-way flows regardless of the one-way flows interfering with each other are described herein. These techniques enable nearly full-rate data flow through frame transmissions, even though these frame transmissions can interfere with substantially concurrent relay transmissions. In some implementations, relays on the two paths forward mixed frame signals to the next hop without trying to decode the mixed frame signals of interfered frames. The destination successfully recovers the useful information from the mixed frame signals by canceling out interference based on previously received frames.

Abstract: Embodiments include processes, systems, and devices that allow a white space base station to request available frequency ranges for white space transmission in a local area. A white space finder service models a primary user device's transmission signal propagation area using terrain data associated with the local area of the primary user device. The white space finder service also determines, based on the location of the white space base station and the modeled propagation area, one or more locally available, non-interfering frequency ranges and provides them to the white space base station. The white space base station compares the provided frequency ranges to policies and selects one or more of the available frequencies that accommodate the policies. The white space base station also maps the transmission frequency ranges to virtual frequency ranges for transmission by a software-defined radio employing spectrum virtualization.

Abstract: Implementations for retransmitting erroneous portions within a transmission frame are described. A sender transmits a transmission frame and the receiver performs error detection on portions of the transmission frame in order to determine if any are received in error. The receiver sets up a feedback channel and transmits acknowledgements to the receiver to indicate that one or more portions have been received and to identify any portions that are received with errors. At least some of the acknowledgements are transmitted prior to receipt of the entire transmission frame. The sender retransmits any portions that are identified as being erroneous within the transmission frame.

Abstract: A method and apparatus are described that result in an improved acquisition of a received communication signal containing a large frequency offset. The method and apparatus raises a derotated sequence of data to a power of an integer provide a sinusoidal spectral component. The method and apparatus determines a cross product based upon the sinusoidal spectral component to provide a phase error. The method and apparatus determines an oscillator signal based upon the phase error. The method and apparatus adjusts the received communication signal based upon the oscillator signal to compensate for the large frequency offset to provide the derotated sequence of data.

Abstract: A real-time task may initially be performed by a first thread that is executing on a first core of a multi-core processor. A second thread may be initiated to take over the performance of the real-time task on a second core of the multi-core processor while the first thread is performing the real-time task. The performance of the real-time tasks is then transferred from the first thread to the second thread with the execution of the second thread on the second core to perform the real-time task.

Abstract: An extensive use of look-up table (LUT) and single instruction multiple data (SIMD) in different algorithms in a software-defined radio (SDR) system is described. In particular, the LUT is used during spreading modulation, mapping and spreading, scrambling, de-scrambling, soft demapping, and the like. The SIMD is executed by a multi-core processor during implementation of a “min” operation to find an optimal path in a Trellis diagram for a Viterbi decoder.

Abstract: A radio control board passes a plurality of digital samples between a memory of a computing device and a radio frequency (RF) transceiver coupled to a system bus of the computing device. Processing of the digital samples is carried out by one or more cores of a multi-core processor to implement a software-defined radio.

Abstract: A method and apparatus is disclosed to compensate for impairments within a data converter such that its output is a more accurate representation of its input. The data converter includes a main data converter, a reference data converter, and a correction module. The main data converter may be characterized as having the impairments. As a result, the output of the main data converter is not the most accurate representation of its input. The reference data converter is designed such that the impairments are not present. The correction module estimates the impairments present within the main data converter using its output and the reference data converter to generate corrections coefficients. The correction module adjusts the output of the main data converter using the corrections coefficients to improve the performance of the data converter.

Abstract: An exemplary powered device (PD) connected to a local power source and a power sourcing equipment (PSE) includes a constant current source drawing at least 10 mA direct current from the PSE when the local power source is in operation. The PD includes a first conversion circuit, a first diode, and a second diode. The first conversion circuit comprises a first input and is configured for converting a voltage input to the first input into the rated working voltage of the PD. The positive terminal of the first diode is connected to the local power source and the negative terminal thereof is connected to the first input. The voltage of the local power source is higher than that of the PSE.

Abstract: A computing device configured for wireless communication may effectively control adaptation to channel conditions. The device may be configured to identify and classify conditions impacting performance of a channel so that appropriate adaptations may be made. Interference may be detected by correlating received signal strength and packet errors. High received signal strength correlated to a high packet error rate may signify presence of a source of interference. Once a source of interference is detected, other criteria may be used to determine the nature of the interference so that an adaptation that is minimally disruptive of applications can be selected. Additionally, channel degradation may be predicted by monitoring trends in error rates, including Forward Error Correction rates, and adaptation may be used before packet error rates exceed an unacceptable level.

Abstract: Embodiments include processes, systems, and devices for reshaping virtual baseband signals for transmission on non-contiguous and variable portions of a physical baseband, such as a white space frequency band. In the transmission path, a spectrum virtualization layer maps a plurality of transmission components associated with a transmission symbol produced by a physical layer protocol to sub-carriers of the allocated physical frequency band. The spectrum virtualization layer then outputs a physical transmission symbol composed of time-domain samples derived from the mapped frequency components and a cyclic prefix. In the receive path, a time-domain symbol received on the physical baseband is reshaped and equalized by the virtual spectrum layer in order to recompose a time-domain samples of a transmission stream in the virtual baseband.

Abstract: Embodiments include processes, systems, and devices for reshaping virtual baseband signals for transmission on non-contiguous and variable portions of a physical baseband, such as a white space frequency band. In the transmission path, a spectrum virtualization layer maps a plurality of frequency components derived from a transmission symbol produced by a physical layer protocol to sub-carriers of the allocated physical frequency band. The spectrum virtualization layer then outputs a time-domain signal derived from the mapped frequency components. In the receive path, a time-domain signal received on the physical baseband is reshaped by the virtual spectrum layer in order to recompose a time-domain symbol in the virtual baseband.