摘要:
Various aspects of a method for and system for multiple input multiple output (MIMO) channel estimation are presented. Aspects of a method for computing channel estimates in a radio frequency (RF) communications system may comprise decomposing a direct matrix computation into a plurality of constituent matrices, and jointly computing a plurality of channel estimates for a corresponding plurality of channel estimate streams received via a plurality of RF channels based on at least a portion of the plurality of constituent matrices. Aspects of a system for computing channel estimates in an RF communications system may comprise a receiver that decomposes a direct matrix computation into a plurality of constituent matrices, and jointly computes a plurality of channel estimates for a corresponding plurality of channel estimate streams received via a plurality of RF channels based on at least a portion of the plurality of constituent matrices.
摘要:
Methods and systems for processing multiple preambles for a wireless signal are disclosed herein. Aspects of the method may comprise selecting a portion of a preamble, and shifting the selected portion of the preamble to generate a plurality of subsequent preambles. The preamble may comprise a legacy preamble and/or an 802.11(n) preamble. The selected portion of the preamble may comprise a short training sequence. The shifting may comprise circular shifting. The circular shifting may comprise forward circular shifting and/or backwards circular shifting. The generated plurality of subsequent preambles may be transmitted via a plurality of antennas. A phase roll may be added to the selected portion of the preamble to generate the plurality of subsequent preambles.
摘要:
Methods and systems for calibrating a transmitter with I/Q imbalance and local oscillator feed-through include generating a test tone, frequency up-converting the test tone, monitoring one or more features of the up-converted test tone, and adjusting one or more features of the transmitter in response to the monitoring. The monitoring optionally includes monitoring a beating of the envelope of the up-converted test tone. In an embodiment, a first harmonic of the up-converted test tone is monitored for local oscillator feed-through (LOFT). Alternatively, baseband data inputs to the transmitter are disabled, and LOFT is measured by measuring power at the transmitter output. A second harmonic of the up-converted test tone is monitored for gain and phase imbalances. The adjusting optionally includes adjusting a gain imbalance, adjusting a phase imbalance, and/or adjusting a DC offset. The adjusting optionally includes an iterative refinement process.
摘要:
Methods and systems for calibrating a transmitter with I/Q imbalance and local oscillator feed-through include generating a test tone, frequency up-converting the test tone, monitoring one or more features of the up-converted test tone, and adjusting one or more features of the transmitter in response to the monitoring. The monitoring optionally includes monitoring a beating of the envelope of the up-converted test tone. In an embodiment, a first harmonic of the up-converted test tone is monitored for local oscillator feed-through (LOFT). Alternatively, baseband data inputs to the transmitter are disabled, and LOFT is measured by measuring power at the transmitter output. A second harmonic of the up-converted test tone is monitored for gain and phase imbalances. The adjusting optionally includes adjusting a gain imbalance, adjusting a phase imbalance, and/or adjusting a DC offset. The adjusting optionally includes an iterative refinement process.
摘要:
Methods and systems to calibrating a transmitter for I/Q imbalance and local oscillator feed-through include generating a test tone, frequency up-converting the test tone, monitoring one or more features of the up-converted test tone, and adjusting one or more features of the transmitter in response to the monitoring. The monitoring optionally includes monitoring a beating of the envelope of the up-converted test tone. In an embodiment, a first harmonic of the up-converted test tone is monitored for local oscillator feed-through (LOFT). Alternatively, baseband data inputs to the transmitter are disabled, and LOFT is measured by measuring power at the transmitter output. A second harmonic of the up-converted test tone is monitored for gain and phase imbalances. The adjusting optionally includes adjusting a gain imbalance, adjusting a phase imbalance, and/or adjusting DC offsets. The adjusting optionally includes an iterative refinement process. Such a refinement process optionally includes performing a first monitoring, applying a set of relatively coarse settings to the one or more features in the transmitter, monitoring the beating resulting from each of the coarse settings, selecting the coarse setting corresponding the smallest beating, applying a set of relatively fine settings centered around the selected coarse setting, wherein the fine settings are more closely related to one another than are the coarse settings, monitoring the beating resulting from each of the fine settings, and selecting the fine setting corresponding the smallest beating.
摘要:
A network device for transmitting a set of known pilot symbols in a communications system utilizing a plurality of transmit sources. The network device includes generating means for generating the set of known pilot symbols to be transmitted for each of the plurality of transmit sources and inserting means for inserting pilot symbols for each of the plurality of transmit sources. The network device also includes creating means for creating a near to full orthogonal matrix over time and frequency using the fewest number of pilot symbols. The pilot symbols are used for at least one of channel, frequency, and phase tracking at a receiving station.
摘要:
Certain embodiments of the invention may be found in a method and system for antenna selection diversity with prediction. An antenna diversity system may use information that it has stored on the antenna selection process in previous frames to predict the starting receiving antenna and the starting transmission antenna for the next frame. The prediction may be based on which antennas were selected in previous frames or may be based metrics associated with performance of the antennas. Prediction may be based on a majority polling scheme of previously selected antennas in a determined number of previous frames. Prediction may also be based on a weighted sum of at least one selection metric for all antennas in a determined number of previous frames. Antenna prediction provides a significant performance improvement by reducing the processing and operational overhead in cases where a transmit or a receive antenna dominates.
摘要:
A receiver includes digital logic for defining a plurality of signal paths for an ingoing digital signal to determine a frame classification. Frames are classified according to a combination of readings of a plurality of correlation block and relative signal (power) strengths. Power detection is specified for frequency bands of interest. The combination of readings and their corresponding pattern may be used to determine whether a frame is being transmitted in a lower bandwidth channel, an upper bandwidth channel or a large bandwidth channel that overlaps the lower and upper bandwidth channels. A transmission type (legacy, mixed mode, Greenfield) may subsequently be determined based upon the identity of the frame channel.
摘要:
Multiple-input-multiple-output (MIMO) timing recovery. A novel approach is presented to perform timing recovery when processing the multiple received signals within a MIMO communication device. This may be implemented for a singular received signal, or a plurality of received signal streams. In addition, this timing recovery may be performed in conjunction with carrier detection to provide more robust performance. Alternatively, indicia and/or signals corresponding to carrier detection of these signals may be provided to timing recovery functionality from carrier detection functionality external to the timing recovery functionality. Certain processing and analysis is performed on a modified correlation function that is generated using samples of moving windows that pass over symbols of a packet. Based on this analysis of the modified correlation function, and sometimes in conjunction with one or more carrier detect signals, timing recovery may be performed thereby locating the point at which decoding of the packet may be performed.
摘要:
An integrated circuit radio transceiver and method therefor comprises a receiver front end that further includes a plurality of in-phase and quadrature phase receive processing block operable at first and second frequency bands wherein each of the receive processing blocks defines an ingoing signal path and further includes a plurality of filtering and amplification blocks disposed within the corresponding ingoing signal path, a plurality of RSSI blocks coupled to receive an ingoing analog signal from a corresponding plurality of nodes disposed throughout the ingoing signal path, each of the plurality of received signal strength indicator blocks producing a signal strength indication, and wherein a baseband processor is operable to receive a selected signal strength indication and to produce at least one gain setting to at least one amplification block within the in-phase or quadrature phase receive processing blocks. In operation, the baseband processor receive a signal strength indication from each RSSI block to determine a total amount of gain and appropriate gain distribution within the receive signal path.