Vixs Systems, Inc.

Cheng-Chou Lan

Cimarron Mittelsteadt

A device includes a signaling interface to receive OFDM signaling for an OFDM channel from multiple transmit nodes, an OFDM receiver to process the OFDM signaling, and a channel allocation module. The channel allocation module allocates subchannels of the channel among transmit nodes by: determining, for each transmit node, a corresponding SNR for each of the subchannels; assigning to each transmit node a corresponding subset of buckets of a set of buckets, the number of buckets in the subset based on a data rate requirement of the transmit node; distributing subchannels among the buckets based on the SNRs of the subchannels; and, for each transmit node, allocating to the transmit node the subchannels distributed to the subset of buckets assigned to the transmit node. The device further includes an OFDM transmitter to transmit configuration information to the transmit nodes, the configuration information representing the allocation of the subchannels.

OFDMA subchannel assignment

A device includes a signaling interface to receive OFDM signaling for an OFDM channel from a plurality of transmit nodes and an OFDM receiver process the OFDM signaling. The device further includes a channel allocation module to determine, for each transmit node, a corresponding SNR for each of a plurality of subchannels of the channel and to allocate, to each transmit node of the plurality of transmit nodes, a corresponding subset of subchannels of the plurality of subchannels. The channel allocation module further is to select, for each subset of subchannels, one or more subchannels for use as pilots by the corresponding transmit node based on the SNRs of the subchannels in the subset. The device further includes an OFDM transmitter to transmit configuration information to the plurality of transmit nodes, the configuration information representing the allocation of the subchannels and the selection of subchannels for use as pilots.

Pilot selection for OFDMA carrier tracking

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.

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Los Angeles, CA, United States of America

Cheng-Chou Lan