Cisco Technology, Inc.

Other

Daniel Joseph Lyons

Brian Donald Hart

Ardalan Alizadeh

Gautam Dilip Bhanage

Khashayar Mirfakhraei

Xu Zhang

Matthew Aaron Silverman

Fred Jay Anderson

Eldad Perahia

Pooya Monajemi

Paul Jeffrey Stager

Bretton Lee Douglas

John Matthew Swartz

James A Amos

David P Petsko

Donald I Sloan

James Friedmann

Brian Hart

Aspects discussed herein include a method and associated network device and computer program product. The method includes receiving a network packet, and estimating, using a preamble of the network packet, a power distribution corresponding to a plurality of subcarriers of a channel. The method further includes estimating a carrier frequency offset using the power distribution, and estimating a clock offset using the carrier frequency offset.

Re-estimating clock offset for frequency-selective wireless channels

In one illustrative example, a device configured for use in a wireless local area network (WLAN) may cause a spatial reuse (SR) adjustment to be performed based on data received from a multi-user receiver procedure for the blind detection and demodulation of colliding packets from multiple stations. This procedure may be performed by one or more access points (APs) and/or distributed sensor nodes, each having such a multi-user receiver. The procedure may involve receiving and decoding, over a channel, a first spatial stream from a first device of a first base service set (BSS) color; simultaneously receiving and decoding, over the channel, a second spatial stream from a second device of a second BSS color (i.e. an overlapping BSS or 'OBSS'); and calculating a signal-to-interference ratio (SIR) based on signal levels associated with the streams. The SR adjustment may involve adjusting an OBSS Packet Detect (PD) (OBSS-PD) threshold.

Spatial reuse (SR) optimization in wireless networks using sensor nodes and actual packet collision measurements

The present disclosure provides for distortion cancellation by receiving a collided signal, the collided signal comprising a plurality of signals that each carry a corresponding packet; for a first signal of the plurality of signals that includes a first packet: amplifying and digitizing the collided signal into a first digital signal at a first gain; and decoding the first packet from the first digital signal; for each signal of the plurality of signals other than the first signal, carrying a given packet: estimating a given linear interference component and a given nonlinear interference component of one or more prior packets to the given packet on the collided signal; removing the given linear interference component and the given nonlinear interference component from the collided signal to produce a given de-interfered signal; and decoding the given packet of the plurality of packets from the given de-interfered signal.

Distortion cancellation

In one embodiment, a process tracks measured carrier frequency offsets (CFOs) of identified transmitters over a period of activity of the identified transmitters, and determines predicted CFOs for the identified transmitters and predicted transmitter behavior as a probability of specific transmitters of the identified transmitters being active at given times based on the activity of the identified transmitters. The process may then determine, based on the predicted CFOs and predicted transmitter behavior, CFO ranges that a receiver should expect for upcoming packets, and instructs the receiver to use the CFO ranges as a prioritized list of dynamically selected CFOs to use to extract single or colliding packets from among potential interferences using frequency demodulation.

Optimized frequency searching for simultaneously received packet detection

The present disclosure provides for distortion cancelled by receiving a collided signal comprising first and second signals carrying respective first and second packets; digitizing the collided signal into a first digital signal and decoding the first packet therefrom; calculating a digital linear interference component of the first packet on the second from an estimated signal re-encoding the decoded first packet; synthesizing an analog linear interference component from the digital linear interference component; determining a digital nonlinear interference component of the first packet on the second from the first digital signal; amplifying the collided signal to produce a second amplified signal; removing the analog linear interference component from the second amplified signal to produce a partially de-interfered signal; removing the digital nonlinear interference component from the partially de-interfered signal to produce a de-interfered signal; and decoding the second packet from the de-interfered signal.

The present disclosure provides for distortion cancelled by receiving a collided signal, the collided signal comprising a first signal carrying a first packet and a second signal carrying a second packet; amplifying and digitizing the collided signal into a first digital signal at a first gain and a second digital signal at a second gain that is greater than the first gain; determining a nonlinear interference component of the first packet on the second packet from the first digital signal; decoding the first packet from the first digital signal; re-encoding the first packet with a first estimated channel effect into an estimated signal; calculating a linear interference component of the first packet on the second packet from the estimated signal; removing the linear interference component and the nonlinear interference component from the second digital signal to produce a de-interfered signal; and decoding the second packet from the de-interfered signal.

Embodiments of the present invention relate to methods and systems for simultaneous communication with multiple wireless communication devices. In some embodiments, a method for simultaneous communication with multiple wireless communication devices includes receiving, using a plurality of antennas at a first wireless station, a plurality of packets, comprised of orthogonal frequency division multiplexing (OFDM) wireless signals, transmitted simultaneously from a plurality of other wireless stations wherein each of the simultaneously transmitted packets includes a plurality of frequency tones, frequency domain transform the received packets, grouping frequency domain transform outputs for each subcarrier, determining a difference between subcarrier groups formed over different sample sets, and determining a set of weights for each subcarrier, wherein the weights are selected such that the first wireless station can at least one of detect or demodulate the received plurality of packets.

System and method for simultaneous communication with multiple wireless communication devices

System and methods for simultaneous communication with multiple wireless communication devices

A method and an apparatus in a first wireless station of a network transmitting to a second wireless station. The network uses multi-tone OFDM signals. The first station includes multiple antennas and a receive and a transmit signal path per antenna. Each receive signal path includes a discrete Fourier transformer determining the tones in a received signal, and each transmit signal path includes an inverse discrete Fourier transformer converting tones to a signal. The method includes determining channel estimates for each tone and each receive path while receiving from the second station, determining transmit weights to transmit to the second station, tone-by-tone weighting a signal for transmission to the second station to produce weighted tone sets for each transmit signal path, and transmitting the weighted tone sets. The first station is configured so that the weighting produces additive beamforming without the second station needing multiple antennas.

Multiple antenna processing on transmit for wireless local area networks

A method for performing Time Difference Of Arrival (TDOA) that eliminates the need for a common time base or clock calibration and a system for implementing the method. The method relies on a packet transmitted from a reference wireless device (first wireless device) with a known propagation delay between the first wireless device and a second device, which serves as a common reference point for all TDOA estimates. When a packet is received from a wireless device by the first wireless device and the second wireless device, the time difference of arrival is computed based on when the signal was received by the first device and the second device, using the known propagation delay to compensate for differences in clocks and frequencies between the first wireless device and the second wireless device.

System and method for performing time difference of arrival location without requiring a common time base or clock calibration

A method for controlling cell size associated with an access point that has a receive sensitivity and an output power. The method includes changing a start of packet threshold and/or a clear channel assessment threshold to vary the cell size of the access point.

High density WLAN system

Described herein is an apparatus for inclusion in a station of a wireless network, and a method implemented in a station of a wireless network. The method includes wirelessly receiving data via each of a plurality of antennas, the data corresponding to a packet of information transmitted from a remote station, sampling the received data corresponding to the received packet to form data samples for each of the antennas, and determining a measure of signal quality from samples of the received data for each of the antennas. The method further includes selecting one of the plurality of receive antennas as the antenna for receiving from the remote station according to the determined measure of signal quality.

Error vector magnitude selection diversity metric for OFDM

A transmit system is disclosed herein that includes two receive inputs for receiving input power distributed between two weakly correlated signals. The transmit system further includes a balanced amplifier system for dividing, amplifying, and recombining the two weakly correlated signals and a two antenna array having a first antenna element and a second antenna element for radiating the amplified signals. The transmit system is capable of unicast and multicast transmissions.

Transmit system employing an antenna and balanced amplifier architecture which provides power amplifier load balancing independent of single or dual signal operation of the transmitter

Describe herein is an apparatus for inclusion in a station of a wireless network, and a method implemented in a station of a wireless network. The method includes wirelessly receiving data via each of a plurality of antennas, the data corresponding to a packet of information transmitted from a remote station, sampling the received data corresponding to the received packet to form data samples for each of the antennas, and determining a measure of signal quality from samples of the received data for each of the antennas. The method further includes selecting one of the plurality of receive antennas as the antenna for receiving from the remote station according to the determined measure of signal quality.

Growing community of inventors

Medina, OH, United States of America

Daniel Joseph Lyons