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.

Abstract: An uncontrolled spatial multiple access system and method facilitating spatial multiple access for multiple devices in a wireless local-area network (WLAN). Embodiments of the system and method increase throughput of the wireless network by facilitating concurrent encoded frame transmission. Decoding of the quasi-overlapped frames is achieved using a chain decoding technique that takes data streams (or signals) containing the quasi-overlapping encoded frames and isolates each encoded frame so that the frame can be decoded. Quasi-overlapped frames means that the frames are overlapped in the body of the frame but not at the preamble (or headers) of the frames. Embodiments of the chain decoding also use interference nullifying and interference cancellation to enable concurrent quasi-overlapping transmission.

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: 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: A fine-grained channel access system and method to facilitate fine-grained channel access in a high-data rate wide-band wireless local-area network (WLAN). Embodiments of the system and method divide an entire wireless channel into proper size subchannels commensurate with the physical layer data rate and typical frame size. Once the subchannels are defined, each node on the WLAN contends independently for each of the fine-grained subchannels. A first orthogonal frequency-division multiplexing (OFDM) technique is used to signal an access point on the WLAN that the node desires one or more of the subchannels. A second OFDM technique (which is different from the first OFDM technique) is used for data transmission. Sometimes there is contention between nodes that want the same subchannel. The access point resolves any contention between the nodes using a frequency domain contention technique that includes a frequency domain backoff technique.

Abstract: An uncontrolled spatial multiple access system and method facilitating spatial multiple access for multiple devices in a wireless local-area network (WLAN). Embodiments of the system and method increase throughput of the wireless network by facilitating concurrent encoded frame transmission. Decoding of the quasi-overlapped frames is achieved using a chain decoding technique that takes data streams (or signals) containing the quasi-overlapping encoded frames and isolates each encoded frame so that the frame can be decoded. Quasi-overlapped frames means that the frames are overlapped in the body of the frame but not at the preamble (or headers) of the frames. Embodiments of the chain decoding also use interference nullifying and interference cancelation to enable concurrent quasi-overlapping transmission.

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: An analysis application is adapted to be executed on a computing device for collecting data for analysis from a software-defined radio implemented on the same computing device or on a separate computing device for testing measurement and analysis of wireless standards, radio configurations, communication protocols and other radio technologies.

Abstract: A radio control board exchanges data with a radio frequency (RF) front end using a messaging protocol over an interface that includes separate data and control channels. Training data can also be passed over the interface for tuning the clock phase.

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 one or more cores of a multi-core processor to implement a software-defined radio.

Abstract: Systems and methods are provided for transmitting data on a wireless network. Some embodiments provide a technique whereby a type is determined for the transmission, at least one metric is determined for the transmission based at least in part on the transmission type and/or an indication of conditions on the channel on which the transmission is to be performed, at least one transmission parameter to be used in performing the transmission is selected to optimize the at least one metric, and the data is transmitted in accordance with the at least one transmission parameter.

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: 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.