摘要:
Systems and methods for digital communication using an inexpensive reference crystal are described herein. Some illustrative embodiments include a method that includes setting a center frequency of a local oscillator used by a radio frequency (RF) transceiver, sequentially applying each of a plurality of predetermined offsets to the center frequency of the local oscillator, determining a plurality of metrics indicative of the quality of a received signal (each of the plurality of metrics corresponding to a different predetermined offset of the plurality of predetermined offsets), and selecting a predetermined offset of the plurality of predetermined offsets that results in a metric indicating a received signal that is higher in quality than the received signal that results when applying each of the remaining predetermined offsets of the plurality of offsets.
摘要:
A system and method of flexible channel allocation in an ultra wideband frequency hopping communication system is disclosed. In one embodiment, a method includes communicating radio signals through rapidly switching among a band group 6 according to a hopping pattern. The method also includes scanning the ultra wideband spectra to determine the band group 6 based on the hopping pattern of the radio signals.In another embodiment, a method includes scanning ultra wideband spectra to eliminate any frequency band of the ultra wideband spectra from a list of available frequency bands when the any frequency band is currently used, selecting a band group in combination of two or more frequency bands to communicate radio signals with an optimal transmission power and/or maximum range, and communicating the radio signals through rapidly switching among the band group.
摘要:
A novel and useful apparatus for and method of packet detection and carrier frequency offset estimation. The packet detection mechanism is robust to channels and sustains reasonable miss-detect (and false alarm) rates at low SNR values. The mechanism uses a modified combined cross correlation and delay and correlate scheme. A delay and correlate scheme is used in order to handle the effects of multipath while swapping integration and multiplication to increase cross-correlation factors resulting in improved sensitivity in low SNR conditions. Correlation is divided into multiple chains to generate a plurality of partial correlations to observe short patterns in the spread sequence resulting in improved performance in long multipath channels.
摘要:
Systems and methods for improving data throughput in an interference-rich wireless environment are described herein. Some illustrative embodiments include a method including receiving a modulated radio frequency (RF) signal including a message packet, identifying a preamble of the message packet generating a correlated preamble by combining the message packet preamble with a correlation sequence corresponding to an expected preamble, determining a characteristic of a correlated signal representing the correlated preamble, comparing the determined characteristic of the correlated signal to a first threshold value, and discarding the message packet if the determined characteristic of the correlated signal is below the first threshold value.
摘要:
A system and method of flexible channel allocation in an ultra wideband frequency hopping communication system is disclosed. In one embodiment, a method includes communicating radio signals through rapidly switching among a band group 6 according to a hopping pattern. The method also includes scanning the ultra wideband spectra to determine the band group 6 based on the hopping pattern of the radio signals.In another embodiment, a method includes scanning ultra wideband spectra to eliminate any frequency band of the ultra wideband spectra from a list of available frequency bands when the any frequency band is currently used, selecting a band group in combination of two or more frequency bands to communicate radio signals with an optimal transmission power and/or maximum range, and communicating the radio signals through rapidly switching among the band group.
摘要:
In at least some embodiments, a communication system includes a receiver having a local oscillator (LO) for each of a plurality of frequency bands. Each LO is controlled by a separate phase-locked loop (PLL) that tracks carrier frequency offset (CFO) using a common phase error (CPE). The CPE is selectively weighted based on at least one inter-band frequency correlation (IFC) coefficient.
摘要:
A novel and useful apparatus for and method of packet detection and carrier frequency offset estimation. The packet detection mechanism is robust to channels and sustains reasonable miss-detect (and false alarm) rates at low SNR values. The mechanism uses a modified combined cross correlation and delay and correlate scheme. A delay and correlate scheme is used in order to handle the effects of multipath while swapping integration and multiplication to increase cross-correlation factors resulting in improved sensitivity in low SNR conditions. Correlation is divided into multiple chains to generate a plurality of partial correlations to observe short patterns in the spread sequence resulting in improved performance in long multipath channels.
摘要:
A spatial diversity receiver and method for determining a multichannel combined symbol timing marker that identifies an energy concentration for a combination of channel delay spreads in order to reduce the complexity of equalization. The receiver includes two or more receiver chains having spatially diverse antennas; a multichannel combined timer; and a multichannel combined equalizer for receiving wireless signals through two or more signal channels. The multichannel combined timer combines energies corresponding to the channel impulse response coefficients for all the channels for determining a series of multichannel combined metrics having associated index cursors, and then determines the multichannel combined symbol timing marker from the index cursor for the largest of the metrics. The symbol timing marker synchronizes the received symbols issued to the equalizer jointly to the energy concentration for the delay spreads combined for all the channels.
摘要:
A multiple access system for a network using multicarrier modulation. To contend for service a subscriber station selects an upcoming frame in whose contention window it will contend, selects a contention slot within the window, selects a contention channel corresponding to a subset of the carriers used by the network, and imposes a contention code differentially on the carriers in the contention channel.
摘要:
A method in accordance with an embodiment of the invention includes producing a first signal match indication based on at least one match indication indicative of a match between at least one signal received in at least one band and a reference signal. The method also includes producing a first signal multipath combined signal based upon the first signal match indication, and detecting a first peak in the first multipath combined signal.