Vixs Systems, Inc.

Cimarron Mittelsteadt

Cheng-Chou Lan

Amit Ranjan Dubey

Michael David Cave

An orthogonal frequency division multiplexing (OFDM) communication system includes a first interface having a first cable coupler to couple to a first end of a coaxial cable, and a first plurality of signal pathways coupled to the first cable coupler. Each signal pathway of the first plurality includes a physical (PHY) layer component and a radio frequency (RF) front end coupled to the PHY layer component. The system further includes a second interface having a second cable coupler to couple to a second end of a coaxial cable, and a second plurality of signal pathways coupled to the second cable coupler. Each signal pathway of the second plurality corresponds to a signal pathway of the first plurality and includes a PHY layer component and an RF front end coupled to the PHY layer component.

Bonded OFDM communication system

A carrier tracking technique includes allocating a first number of bits per symbol to a carrier tracking subcarrier of a plurality of subcarriers of an orthogonal frequency division multiplexing (OFDM) signal based on a first target performance margin. The technique includes allocating numbers of bits per symbol to other subcarriers of the plurality of subcarriers based on a second target performance margin.

Carrier tracking without pilots

An automatic gain control technique generates one or more gain control signals based on a known sequence of samples received in a preamble of a packet received over a particular communications link and generates one or more adjusted gain control signals based on a previously unknown sequence of samples received in a payload of a packet. In at least one embodiment of the gain control technique, time domain samples of the preamble of a symbol are used to generate the one or more gain control signals. In at least one embodiment of the gain control technique, frequency domain samples are used to generate the one or more adjusted gain control signals. The one or more gain control signals include digital and/or analog gain control signals that are provided to digital signal processing modules and/or analog circuits in an interface circuit, respectively, to adjust the gain applied to a received signal.

Automatic gain control in a communications system

A technique detects the presence of a packet identification sequence in a received sequence of samples received over a communications network. The packet identification sequence, when present and properly detected in a received packet, is used to determine a particular type of the received packet from a plurality of packet types that may be received over the communications network. The technique for detecting the packet identification sequence includes detecting a null sequence in the received packet and a predetermined identification sequence in the packet. Detection of the predetermined sequence uses energy estimates for corresponding windows of received samples.

Detection of a packet type in a communications system

A method includes generating representative noise variance estimates based on a plurality of received symbols received in an orthogonal frequency division multiplexing (OFDM) signal. The representative noise variance estimates correspond to respective frequency intervals of a plurality of frequency intervals of the OFDM channel. Individual frequency intervals of the plurality of frequency intervals include a plurality of contiguous frequency bins of the OFDM signal.

Channel estimation in a communications system

A method of operating a communications system includes generating a channel impulse response estimate based on a first received signal. The method includes selecting a precursor and a cyclic prefix length for a second received signal based on the channel impulse response estimate, a target cyclic prefix energy level, and a predetermined range of cyclic prefix lengths.

Cyclic prefix and precursor joint estimation

A coarse timing acquisition technique includes generating a sequence detection indicator. The sequence detection indicator indicates detection of a sequence of repeated symbols in a received signal. The sequence detection indicator is based on a first energy threshold and a normalized moving sum of an autocorrelation signal. The autocorrelation signal is based on the received signal.

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Cimarron Mittelsteadt