Mohammad M Janani

US Patent:

8374271, Feb 12, 2013

Filed:

Dec 13, 2007

Appl. No.:

11/956280

Inventors:

Ahmadreza Hedayat - Allen TX, US
Genyuan Wang - Plano TX, US
Mohammad Janani - Plano TX, US
Hanqing Lou - Garland TX, US

Assignee:

Cisco Technology, Inc. - San Jose CA

International Classification:

H04B 7/02

US Classification:

375267, 375260, 375262, 375271, 375295, 375299

Abstract:

The present invention discloses a method for generating a signal stream in a multiple-input-multiple-output (MIMO) channel of a wireless communications system. The method comprises encoding at least one transmitting message into a first signal sequence, transforming the first signal sequence into a second and a third signal sequence by a first and a second predetermined rule, respectively, coupling the second signal sequence to a first antenna, coupling the third signal sequence to a second antenna, transmitting a signal stream comprising the first and second signal sequences to a mobile station.

US Patent:

8638834, Jan 28, 2014

Filed:

Jul 15, 2009

Appl. No.:

12/503277

Inventors:

Ahmadreza Hedayat - Allen TX, US
Mohammad Janani - Plano TX, US
Hang Jin - Plano TX, US

Assignee:

Cisco Technology, Inc. - San Jose CA

International Classification:

H04B 1/00
H04B 7/212
H04B 15/00

US Classification:

375146, 370324, 455502

Abstract:

Energy in a frequency band is received at a wireless communication device and data is generated representing samples of a received time domain waveform from the received energy. Data for groups of samples of the received time domain waveform is processed to transform the data for the received time domain waveform to produce data for an intermediate domain signal that is in neither the time domain nor the frequency domain. The data representing the intermediate domain signal is analyzed to determine whether a sequence having a predetermined pattern from a set of possible sequences is present in the received energy, and ultimately to determine a sequence of the predetermined pattern whose presence is detected in the received energy.

US Patent:

20080101437, May 1, 2008

Filed:

Aug 17, 2007

Appl. No.:

11/840788

Inventors:

Mohammad Janani - Plano TX, US
Ahmadreza Hedayat - Allen TX, US
Hang Jin - Plano TX, US

International Classification:

H04B 1/713

US Classification:

375131, 375E01033

Abstract:

A method for providing a fast fading channel in a MIMO communication system is disclosed. The method includes encoding a series of source data to generate a first plurality of encoded output signals and multiplying the first plurality of encoded output signals by a plurality of random complex numbers to generate a second plurality of encoded output signals, and transmitting the second plurality of encoded output signals via the corresponding plurality of antennas, wherein the transmitting signals vary in time and frequency independent of the channel conditions.

US Patent:

20120082262, Apr 5, 2012

Filed:

Oct 4, 2010

Appl. No.:

12/896994

Inventors:

Mohammad Janani - Plano TX, US
Mahendra Mandava - Richardson TX, US
Ahmadreza Hedayat - Allen TX, US
Bror Peterson - Murphy TX, US

Assignee:

CISCO TECHNOLOGY, INC. - San Jose CA

International Classification:

H04L 25/03
H04L 27/00

US Classification:

375296, 375295

Abstract:

Techniques are provided for crest factor reduction of a symbol to be transmitted by a communication device. The symbol may be an orthogonal frequency division multiplexed (OFDM) formatted symbol. In a communication device, samples of the symbol are clipped with a clipping level. A signal quality of the symbol is computed after it is clipped. A determination is made as to whether the signal quality satisfies a predetermined criterion. When the signal quality does not satisfy the predetermined criterion, the clipping level is adjusted. The clipping, computing, determining and adjusting operations are repeated until the signal quality satisfies the predetermined criterion. The symbol clipped by the clipping level determined to result in satisfying the predetermined criterion is output for supply to a transmitter in the communication device. Techniques for computing for error vector magnitude that are faster and less computationally intensive are provided, as well as a computation for distortion that can be used as a measure of error vector magnitude.

US Patent:

20120328053, Dec 27, 2012

Filed:

Jun 27, 2011

Appl. No.:

13/169172

Inventors:

Mohammad Janani - Plano TX, US
Ahmadreza Hedayat - Allen TX, US

Assignee:

Cisco Technology, Inc. - San Jose CA

International Classification:

H03K 9/00
H04L 27/06
H03D 1/24

US Classification:

375320, 375316, 375340

Abstract:

Techniques are provided for generating an estimate of the phase and magnitude imbalance of a receiver in a communication device. For each of a plurality of symbols in a signal received by the communication device, a plurality of tones that make up the symbol are obtained. For each of the plurality of symbols, each tone is multiplied by its respective mirror tone to produce a plurality of mirror tone multiplication results, and the plurality of the mirror tone multiplication results are summed over tones to produce a sum of multiplication results for each symbol. The total power of all tones for each symbol is obtained to produce a tone power quantity for each symbol. The estimate of the phase and magnitude imbalance in the received signal is generated based on the sum of the multiplication results for each of the plurality of symbols and the tone power quantity for each of the plurality of symbols.

US Patent:

20130128935, May 23, 2013

Filed:

Nov 17, 2011

Appl. No.:

13/298857

Inventors:

Mohammad Janani - Plano TX, US
Ahmadreza Hedayat - Allen TX, US
Matthew A. Silverman - Shaker Heights OH, US

Assignee:

CISCO TECHNOLOGY, INC. - San Jose CA

International Classification:

H04B 7/02
H04B 1/38

US Classification:

375222, 375267

Abstract:

Techniques are provided to compute downlink beamforming weights for beamforming multiple spatial streams to a wireless device when that wireless device does not transmit with a maximum number of spatial streams, and thus when the full dimensional knowledge of the wireless channel to that wireless device needs to be implicitly derived. Uplink signals are received at a plurality of antennas of a first wireless device that are transmitted via a plurality of antennas of a second wireless device. The first wireless device derives values at a plurality of subcarriers of the received signals across the plurality of antennas of the first wireless device. Downlink beamforming weights are computed from values of consecutive subcarriers across the plurality of antennas of the first wireless device. The first wireless device applies the downlink beamforming weights at respective subcarriers to a number of spatial streams to be transmitted to the second wireless device.

US Patent:

20130201863, Aug 8, 2013

Filed:

Feb 7, 2012

Appl. No.:

13/367446

Inventors:

Douglas Chan - San Jose CA, US
Tak Ming Francis Pang - Palo Alto CA, US
Mohammad Janani - Plano TX, US

Assignee:

CISCO TECHNOLOGY, INC. - San Jose CA

International Classification:

H04W 24/00
H04L 12/26

US Classification:

370253

Abstract:

Devices, methods and instructions encoded on computer readable media are provided herein for estimation of the available bandwidth in a frequency channel shared by a first access point and at least one neighboring access point. In one example, an impact value that represents the impact of traffic associated with the neighboring access point on the first access point is calculated. Based on the impact value, a first utilization metric associated with the first access point is generated. The first utilization metric represents the bandwidth available on the frequency channel in the presence of the traffic associated with the neighboring access point.

US Patent:

20130286863, Oct 31, 2013

Filed:

Apr 30, 2012

Appl. No.:

13/459330

Inventors:

Matthew A. Silverman - Shaker Heights OH, US
Paul J. Stager - Akron OH, US
Brian D. Hart - Sunnyvale CA, US
Mohammad Janani - Plano TX, US
Ahmadreza Hedayat - Allen TX, US

Assignee:

CISCO TECHNOLOGY, INC. - San Jose CA

International Classification:

H04W 24/00
H04W 72/04

US Classification:

370252

Abstract:

Techniques are provided to determine whether or not incident power at a wireless communication device in at least two frequency channels is from the same device. Incident power in frequency channels allocated to a basic service set in a wireless network is received at a plurality of antennas of the wireless communication device. Channel state information is computed for at least two frequency channels allocated to the basic service set. One or more metrics are generated based on the channel state information in the two frequency channels. The one or more metrics are evaluated to characterize an uplink signal bandwidth associated with the two channels to determine whether or not the incident power in the two channels is from the same device.