摘要:
The present invention provides a time-orthogonal preamble supplement generator for use with a multiple-input, multiple-output (MIMO) transmitter employing N transmit antennas, where N is at least two. In one embodiment, the time-orthogonal preamble supplement generator includes an initial preamble supplement encoder configured to provide a preamble supplement to each of the N transmit antennas during an initial time interval. The time-orthogonal preamble supplement generator also includes a subsequent preamble supplement encoder coupled to the initial preamble supplement encoder and configured to provide the preamble supplement or a negation thereof to the N transmit antennas during (N−1) subsequent time intervals.
摘要:
For use with a multiple-input, multiple-output (MIMO) transmitter, an orthogonal preamble encoder, a method of encoding orthogonal preambles and a communication system incorporating the encoder or the method. In one embodiment, the encoder includes: (1) a preamble supplement generator configured to provide a first long sequence preamble supplement to a first transmit antenna of the MIMO transmitter and (2) a preamble supplement coordinator coupled to the preamble supplement generator and configured to provide a second long sequence preamble supplement to a second transmit antenna of the MIMO transmitter, at least a portion of the second long sequence preamble supplement being a negation of the first long sequence preamble supplement.
摘要:
The present invention provides a time-switched preamble supplement generator for use with a multiple-input, multiple-output (MIMO) transmitter employing N transmit antennas wherein N is at least two. In one embodiment, the time-switched preamble supplement generator includes an initial preamble supplement formatter configured to provide a first permutation of a set of preamble supplements to the N transmit antennas during an initial time interval. The first permutation includes a single first preamble supplement and at least one second preamble supplement. The time-switched preamble supplement generator also includes a subsequent preamble supplement formatter coupled to the initial preamble supplement formatter and configured to provide (N−1) mutually exclusive further permutations of the set to the N transmit antennas during (N−1) subsequent time intervals.
摘要:
A method of correctly estimating the frequency offset when the CPE modem has already acquired and is tracking the OFDM burst boundaries in an OFDM-based, wireless communication system. CPS data in an OFDM-based, wireless communication system is modulated as QPSK data in the training tones of the data burst. As long as some bursts have the CPS data modulation and some bursts do not have the CPS data modulation, the CPS data can be recovered. A slip results when there is a linear phase difference across the tones (after the FFT) between the current and the previous burst. This linear phase difference is generally taken care of by the channel estimation obtained using the pilot tones. This phase difference is however, now compensated for correct frequency offset estimation which occurs before the channel estimation and CPS decoding steps.
摘要:
The present invention is directed to a time-switched preamble generator and method of generating a time-switched preamble for use with a multiple-input, multiple-output (MIMO) transmitter employing first and second transmit antennas. In one embodiment, the time-switched preamble generator includes an initial preamble formatter configured to provide a first preamble to the first transmit antenna and a second preamble to the second transmit antenna during an initial time interval. The time-switched preamble generator also includes a subsequent preamble formatter coupled to the initial preamble formatter and configured to provide the second preamble to the first transmit antenna and the first preamble to the second transmit antenna during a subsequent time interval.
摘要:
A transmit channel (gt1, h, gr2) through which a first wireless communication transceiver is to transmit to a second wireless communication transceiver can be estimated using information indicative of a relationship between the transmit channel and a receive channel (gt2, h, gr1) through which the first wireless communication transceiver receives communications from the second wireless communication transceiver. The relationship information (35) is combined (37) with further information (31) to produce an estimate of the transmit channel.
摘要:
A method of determining CPS data in an OFDM-based, wireless communication system resolves the phase angle difference between training tones in a burst without CPS data and training tones in a burst with CPS data and then demodulates the resulting difference phase angles to determine the CPS data. The method achieves timing correction/compensation in CPS decode operations associated with OFDM-based, wireless communication systems.
摘要:
The present invention provides an FFT/IFFT processor for use with N data values. In one embodiment, the FFT/IFFT processor includes an even-odd data mapper configured to provide a mapping of the N data values into N/2 mapped complex data values if the N data values are real. Additionally, the FFT/IFFT processor also includes a separator-combiner, coupled to the even-odd data mapper, configured to compute either an FFT based on the mapping or an IFFT based on the N data values if the N data values are complex.
摘要:
A position sensor includes a stationary platform and a moveable platform. The position sensor further includes at least one beam coupling the moveable platform to the stationary platform. The at least one beam includes piezoresistive material that is positioned tolprovide an indication of a movement of the moveable platform relative to the stationary platform.
摘要:
According to one embodiment of the invention, a method of moving a device from a first position to a second position by an actuation system includes moving the device in response to providing a control signal having a first amplitude for a first time period. The method also includes, immediately after the first time period, moving the device in response to providing a control signal having a second amplitude for a second time period, the device having a nonzero velocity after the second time period. The nonzero velocity has a magnitude that allows the device to coast to, and stop at, the second position after the second time period without receiving a control signal.