Subburajan Ponnuswamy

7769050, Aug 3, 2010

Apr 25, 2008

12/109474

Shimon B. Scherzer - Sunnyvale CA, US
Patrick A. Worfolk - Campbell CA, US
Armin D. Haken - San Francisco CA, US
Ronen Vainish - Sunnyvale CA, US
Subburajan Ponnuswamy - Scotts Valley CA, US

Hewlett-Packard Development Company, L.P. - Houston TX

H04J 1/00

370480, 370328, 370343

Disclosed are systems and methods which provide interference mitigation by making alternative resources available within areas served by wireless communication links. Embodiments provide multiple channel availability in establishing wireless communication links to facilitate interference mitigation. Time domain techniques, spatial processing techniques, and/or frequency domain techniques may be implemented for spectrum management. Embodiments provide wireless base station configurations in which all or a plurality of base station sectors use a same frequency channel and/or in which each sector or a plurality of sectors use all frequency channels. Multi-channel strategies may be implemented such as to provide dynamic selection of a “best” frequency channel, to provide transmission of identical data on multiple channels for combining/selection at the receiver, and/or to provide for dividing the data for transmission on multiple channels.

7366202, Apr 29, 2008

Dec 8, 2003

10/730649

Shimon B. Scherzer - Sunnyvale CA, US
Patrick A. Worfolk - Campbell CA, US
Armin D. Haken - San Francisco CA, US
Ronen Vainish - Sunnyvale CA, US
Subburajan Ponnuswamy - Scotts Valley CA, US

Colubris Networks, Inc. - Waltham MA

H04J 1/00

370480, 370328, 370343

Disclosed are systems and methods which provide interference mitigation by making alternative resources available within areas served by wireless communication links. Embodiments provide multiple channel availability in establishing wireless communication links to facilitate interference mitigation. Time domain techniques, spatial processing techniques, and/or frequency domain techniques may be implemented for spectrum management. Embodiments provide wireless base station configurations in which all or a plurality of base station sectors use a same frequency channel and/or in which each sector or a plurality of sectors use all frequency channels. Multi-channel strategies may be implemented such as to provide dynamic selection of a “best” frequency channel, to provide transmission of identical data on multiple channels for combining/selection at the receiver, and/or to provide for dividing the data for transmission on multiple channels.

8223072, Jul 17, 2012

Apr 29, 2009

12/432614

Subburajan Ponnuswamy - Scotts Valley CA, US

Aruba Networks, Inc. - Sunnyvale CA

H01Q 3/02

342374

Multi-pattern transmission of wireless frames. A digital device contains a transmitter feeding an electronically steerable antenna system where the radiation pattern produced by the antenna system may be selected. Different antenna radiation patterns are used in transmitting a first portion of a wireless frame and a second portion of a wireless frame in a wireless digital network. In one embodiment, a first portion of a wireless frame is transmitted using a wide radiation pattern while the second portion of the frame is transmitted using a second radiation pattern. Switching among radiation patterns in the electronically steerable antenna system may be accomplished by switching between antenna types, such as an omnidirectional antenna for the wide pattern, and beam-steered or sectorized antennas for the second radiation pattern. Beam-forming and/or phasing approaches may also be used. The first and second portions of the frame may be transmitted at different power levels.

8514057, Aug 20, 2013

Nov 16, 2010

12/947579

Subburajan Ponnuswamy - Cupertino CA, US

Aruba Networks, Inc. - Sunnyvale CA

G08B 5/22

340 81, 34053913, 34053923

Determining the location of a wireless device to be located (DTL) by three or more locating devices (LDs). LDs operating at known locations estimate the distance to the DTL by sending wireless frames to the DTL and varying frame parameters such as transmit power and data rate, searching for the boundary at which the frame is or is not received and ACKd by the DTL. For a given set of frame parameters, the SNR required to be successfully received at the DTL is known. Given that the configuration of the LD is known, the EIRP of the DL is also known. Estimating the noise floor at the DTL, and using the SNR required to successfully receive the frame at the DTL and the EIRP at the LD transmitting the frame, the path loss can be calculated. From the path loss and operating frequency, a distance estimate is calculated. EIRP of the DTL is not and need not be known.

8625436, Jan 7, 2014

Apr 5, 2011

13/080552

Subburajan Ponnuswamy - Cupertino CA, US

Aruba Networks, Inc. - Sunnyvale CA

H04L 12/26

370241, 370310, 370328, 370338

Methods of aggregating spectrum data captured from a narrowband radio to form a spectrum covering a much wider frequency band. Frequency data, such as FFT spectrum data captured from a narrowband receiver such as an IEEE 802. 11 Wi-Fi receiver are combined to display representative real-time FFT, average FFT, and FFT duty cycle data of a wideband spectrum. Data is captured from narrow band radios such as access points, station monitors, or client devices on a wireless network. A wideband spectrum may be aggregated from data captured from one or from multiple devices. Data may be stored for later analysis and display.

20090274129, Nov 5, 2009

Apr 30, 2008

12/112285

Subburajan Ponnuswamy - Scotts Valley CA, US

ARUBA NETWORKS, INC. - Sunnyvale CA

H04Q 7/24

370338

Distributed load balancing in wireless digital networks. In a network having a plurality of access nodes with at least one wireless client connected to a first access node, the client is encouraged to move to a different access node by reducing the apparent signal strength of transmissions from the access node to the client. Apparent signal strength can be reduced by reducing transmit power, by using beam forming, antenna switching, or a combination. Other access nodes may send unsolicited frames, such as probe response frames to the client, encouraging the client to move.

20110182383, Jul 28, 2011

Jan 27, 2010

12/695017

Subburajan Ponnuswamy - Cupertino CA, US

H04L 27/00

375316

Estimating frequency spectrum for digital signals. A frequency spectrum for a digital signal is estimated using a stored template. A frame is received by a receiver on the network. A template is selected from a group of templates based on the received signal parameters, which may include modulation and coding, duration, channel and channel bandwidth, preamble type, beam-forming information, source identifier, and PHY rate. There may be a template for each combination, or a template for a set of related signal types. The template amplitude is scaled based on the signal strength of the received signal to create an estimate of the frequency spectrum, and may also be scaled on duration. The templates may be generated for example to represent IEEE 802.11 transmission modes and rates. Each template represents a frequency spectrum, as an example a FFT spectrum, taken at a specific signal strength. The duration of the frame is later used to calculate the spectrum duty cycle. Spectrum estimation may be performed on the receiver or the device hosting the receiver, with the estimated spectrum sent to a monitoring host, or the signal parameters, strength, and duration may be sent to the monitoring host where spectrum estimation is performed.

20110188544, Aug 4, 2011

Jan 28, 2011

13/016458

Subburajan Ponnuswamy - Cupertino CA, US

H04B 1/713
H04L 27/06

375136, 375340, 375E01033

Interference classification with minimal or incomplete information. Receivers in access points and in other network devices on a wireless digital network may be switched to a spectrum monitor mode in which they provide amplitude-versus-frequency information for a chosen part of the spectrum. This may be performed by performing a FFT or similar transform on the signals from the receiver. Receivers are calibrated with known interference sources in controlled environments to determine peaks, pulse frequency, bandwidth, and other identifying parameters of the interference source in best and worst case conditions. These calibrated values are used for matching interference signatures. Calibration is also performed using partial signatures collected over a short period in the order of microseconds. These partial signals may be used to detect interferers while scanning. Another aspect of the invention is to record the variation of noise floor in the presence of interference sources. Multiple interference sources may be detected. While data collection is performed in one or more APs, classification may be performed in theAP or on other systems associated with the network collecting and processing spectrum information from one or more APs.