Abstract:
A first network device including a medium access control module and a physical layer module. The medium access control module is configured to generate a frame to include a first header, a second header and a payload. The first header indicates a start of the frame for a second network device. The second header indicates a length of the payload for the second network device. The payload comprises a third header and data. Other than the payload, a format of the frame complies with IEEE 802.15.4. The physical layer module is configured to: receive the frame; repetition code the third header or repetition code the data; generate a signal including (i) the first header, (ii) the second header, and (iii) the repetition coded third header or the repetition coded data; modulate the signal; and transmit the modulated signal to the second network device.
Abstract:
A robust differential receiver is described that may be used in any frequency modulated system, including short-range radio frequency (RF) communication devices. The differential receiver provides a preamble detection approach that reduces false preamble detection, a fine carrier frequency (CFO) estimation approach that provides an extended estimation range, and robust in-band and out-of-band interference detection. The described differential receiver assures that preamble detections are not falsely triggered, and that CFO estimates are based on accurately modeled preamble waveforms that have not been distorted by phase ambiguities or in-band distortion. In this manner, the described robust differential receiver assures that CFO estimates used to compensate remaining portions of detected signals are accurate, thereby reducing the likelihood that remaining portions of the detected signal will be affected by phase ambiguity distortions, thereby enhancing the differential receiver's ability to lock onto an otherwise unavailable communication channel, and/or reducing transmission errors and/or packet loss.
Abstract:
Systems and methods are provided for processing a payload portion of a received signal in a single carrier mode or a multiple carrier mode based on a portion of the received signal. A single carrier signaling portion is received at a first rate, and whether the payload portion of the signal is a single carrier signal or a multiple carrier signal is detected from the received single carrier signaling portion. The payload portion of the received signal is received at the first rate and demodulated in a single carrier mode if the detecting determines that the payload portion of the received signal is a single carrier signal, and the payload portion of the received signal is demodulated in a multiple carrier mode if the detecting determines that the payload portion of the received signal is a multiple carrier signal.
Abstract:
A receiver device detects a plurality of symbols in a signal and determines, based on the one of the plurality of detected symbols, an estimated beginning of a subsequent frame. The receiver device determines whether the estimated start of the subsequent frame corresponds to an actual start of the subsequent frame. When the estimated start of the subsequent frame corresponds to the actual start of the subsequent frame, the receiver is synchronized to the actual start of the frame. When the estimated start of the subsequent frame does not corresponds to the actual start of the subsequent frame, the receiver device determines, based on a further one of the plurality of detected symbols, an estimated beginning of another subsequent frame. The receiver device determines whether the estimated start of the other subsequent frame corresponds to an actual start of the other subsequent frame.
Abstract:
A communication device determines an estimate of a communication channel, and determines, based on the estimate of the communication channel, a plurality of pairs of modulation schemes and encoding schemes to be used for a packet, including: i) determining, for a first set of adjacent orthogonal frequency division multiplexing (OFDM) subcarriers, a first pair of a modulation scheme and an encoding scheme; and ii) determining, for a second set of adjacent OFDM subcarriers, a second pair of a modulation scheme and an encoding scheme, the second pair being different than the first pair. The communication device generates the packet for transmission, wherein i) all data modulated on the first set of adjacent OFDM subcarriers is modulated and encoded using the first pair, and ii) all data modulated on the second set of adjacent OFDM subcarriers is modulated and encoded using the second pair.
Abstract:
A communication device determines an estimate of a communication channel, and determines, based on the estimate of the communication channel, a plurality of bit rates to be used for a data unit, including: determining a first bit rate for a first set of one or more orthogonal frequency division multiplexing (OFDM) subcarriers, and determining a second bit rate for a second set of one or more OFDM subcarriers, the second bit rate being different than the first bit rate. The communication device generates the data unit for transmission, wherein i) all data modulated on the first set of one or more OFDM subcarriers corresponds to the first bit rate and ii) all data modulated on the second set of one or more OFDM subcarriers corresponds to the second bit rate.
Abstract:
Devices, systems, methods, and other embodiments associated with phase based transformation of repeated signals are described. In one embodiment, an apparatus includes duplication logic configured to duplicate a string of data to form a duplicate string of data. Transformation logic is configured to modify phases associated with the string of data to generate a modified string of data. Signal generation logic is configured to generate a signal for wireless transmission where the signal having at least the modified string of data and the duplicate string of data.
Abstract:
Systems and techniques relating to wireless communications are described. A described technique includes receiving a signal via a wireless channel, performing code synchronization by at least using a peak counter to count peak correlations based on the signal and a known preamble, performing frequency synchronization based on the signal, and using, based on a successful completion of the code synchronization, at least a result of the frequency synchronization to demodulate data from the signal. The technique includes starting the frequency synchronization during the code synchronization when an output value of the peak counter satisfies a predetermined criterion.
Abstract:
A plurality of received signals are received at a first communication device, the plurality of received signals corresponding to at least one training signal having been transmitted by a second communication device a plurality of times via a plurality of antennas by the second communication device applying a respective antenna weight vector from a plurality of different antenna weight vectors each time the at least one training signal is transmitted. The first communication device generates a transmitter antenna weight vector based on a mathematical combination of at least i) the plurality of received signals, ii) the antenna weight vectors applied by the second communication device when transmitting the at least one training signal the plurality of times, and iii) the at least one training signal. The first communication device transmits the transmitter antenna weight vector to the second communication device.
Abstract:
Methods and apparatus are provided for adaptively selecting a communications mode in high frequency systems. A first dual-mode device having capabilities of using two or more high frequency communications modes, such as OFDM and SC modulation, may transmit a signal to a second dual-mode device with the same capabilities. The second dual-mode device may compute a channel characteristic associated with a high frequency communications channel and select an optimal high frequency communications mode. The second dual-mode device may transmit information indicative of the channel characteristic or the selected communications mode to the first dual-mode device. The first dual-mode device may select and operate using the optimal high frequency communications mode based on the information received from the second dual-mode device. The first and second dual-mode devices may communicate using the selected high frequency communications mode.