Syed Azizur Rahman

US Patent:

7050515, May 23, 2006

Filed:

Nov 15, 2001

Appl. No.:

09/999060

Inventors:

Syed Habib Rahman - Campbell CA, US

Assignee:

Terayon Communication Systems, Inc. - Santa Clara CA

International Classification:

H04L 27/08
H04B 3/00

US Classification:

375345, 375257

Abstract:

A control word generator comprised of circuitry to generate a control word to control an attenuator. The control word generator includes a counter that increments at a clock rate much higher than the refresh rate at which the error signal is recalculated. The counter is controlled by a comparator which compares the error signal to a reference value, which, starting from a programmable upper limited is decremented in the counter's incrementation rate by a programmable step size. When the reference value equals the error signal, the comparator changes state and the counter stops incrementing. The count at that time is the control word, which if everything operated instantaneously, would be the control word that would alter the attenuation sufficiently to achieve nominal power. Also disclosed is a method to use this apparatus to generate a table of control words comprising: first establish an input power level and attenuate the signal with an analog variable attenuator/amplifier; second, measuring the output power of the signal output by said variable attenuator/amplifier; third, use a control word generator to iteratively derive a control word, which will cause the input signal power to be altered to the nominal power level; fourth, record that control word; fifth, increment the input signal power and repeat the process to derive a new control word and record that word; and, sixth, repeat the entire process for each level of expected input signal power.

US Patent:

7239678, Jul 3, 2007

Filed:

Jan 19, 2006

Appl. No.:

11/337120

Inventors:

Syed Habib Rahman - Campbell CA, US

Assignee:

Terayon Communications Systems, Inc. - Santa Clara CA

International Classification:

H04L 27/08

US Classification:

375345, 4552341, 4552401

Abstract:

A control word generator comprised of circuitry to generate a control word to control an attenuator. The control word generator includes a counter that increments at a clock rate much higher than the refresh rate at which the error signal is recalculated. The counter is controlled by a comparator which compares the error signal to a reference value, which, starting from a programmable upper limited is decremented in the counter's incrementation rate by a programmable step size. When the reference value equals the error signal, the comparator changes state and the counter stops incrementing. The count at that time is the control word, which if everything operated instantaneously, would be the control word that would alter the attenuation sufficiently to achieve nominal power. Also disclosed is a method to use this apparatus to generate a table of control words comprising: first establish an input power level and attenuate the signal with an analog variable attenuator/amplifier; second, measuring the output power of the signal output by said variable attenuator/amplifier; third, use a control word generator to iteratively derive a control word, which will cause the input signal power to be altered to the nominal power level; fourth, record that control word; fifth, increment the input signal power and repeat the process to derive a new control word and record that word; and, sixth, repeat the entire process for each level of expected input signal power.

US Patent:

59995246, Dec 7, 1999

Filed:

Jun 7, 1996

Appl. No.:

8/660454

Inventors:

Charles Corbalis - Saratoga CA
Muthu Muthuraman - Cupertino CA
Syed Rahman - San Jose CA
Paul Farah - Santa Clara CA
Shyla Bearelly - Sunnyvale CA
Gary L. Beckstrom - Sunnyvale CA

Assignee:

Cisco Technology, Inc. - San Jose CA

International Classification:

H04Q 1104
H04J 324

US Classification:

370352

Abstract:

A data communications system consists of a number of interconnected nodes forming a frame relay network. A user accesses the network by dialing in via a dial access server (DAS). The DAS-to-frame relay interface supports CCITT Recommundation Q. 931 protocols for call control. A data link connection identifier (DLCI) for use in the DAS-to-frame relay network interface is provided in a Q. 931 call establishment message.

US Patent:

52746356, Dec 28, 1993

Filed:

Nov 18, 1992

Appl. No.:

7/977683

Inventors:

Syed A. Rahman - San Jose CA
James P. O'Hare - Felton CA

Assignee:

Stratacom, Inc. - San Jose CA

International Classification:

H04L 1266

US Classification:

370 601

Abstract:

A method and apparatus for aligning a digital communication data stream across a cell network, wherein plurality of timeslot samples are generated by sampling the digital communication data stream transferred over a first circuit-switching communication link. The timeslot samples are assembled into a series of communication cells in a bit or byte skewed arrangement. An align flag in the header of a communication cell indicates that the communication cell contains an aligned timeslot sample.

US Patent:

60288582, Feb 22, 2000

Filed:

Jun 7, 1996

Appl. No.:

8/659217

Inventors:

Henry Rivers - San Jose CA
Charles Corbalis - Saratoga CA
Muthu Muthuraman - Cupertino CA
Syed Rahman - San Jose CA
Paul Farah - Santa Clara CA
Shyla Bearelly - Sunnyvale CA

Assignee:

Cisco Tenchology, Inc. - San Jose CA

International Classification:

H04L 1256

US Classification:

370352

Abstract:

A data communications network consists of a number of interconnected nodes and a network station having a memory. The memory stores a data base containing predefined circuit provisioning information for a number of users. A user accesses the frame relay network by dialing into the network via an ISDN connection. When the user calls into the network, signaling information is received at a first node of the network and passed to the network station. The signaling information includes automatic number identification (ANI) information which identifies the calling user. The network station uses the ANI to index the data base and retrieve associated circuit provisioning information. The circuit provisioning information is used to automatically install a circuit according to the predefined information. In this way, the user is provided with dial access to the frame relay network.

US Patent:

20190007254, Jan 3, 2019

Filed:

Jul 17, 2018

Appl. No.:

16/038163

Inventors:

- SHENZHEN, CN
Syed Habib RAHMAN - Cupertino CA, US
Xiaoshu SI - Wuhan, CN
Fan WANG - Wuhan, CN
Hao LEI - Xi'an, CN

International Classification:

H04L 27/26

Abstract:

A method and an apparatus for determining a time offset are disclosed. The method includes: obtaining, by a device at a head end, a time-domain signal based on a received signal; and then determining a time offset based on values of peak-to-average ratios of a preset quantity of symbols starting from a qsymbol in the time-domain signal, where a peak-to-average ratio of the qsymbol is greater than a preset threshold. A new method for determining a time offset is provided, and takes advantages that the time-domain signal obtained by the device at the head end has stronger capabilities of resisting interference such as frequency offset and phase noise. The method for determining a time offset can be applied both to initial ranging and periodic ranging.

US Patent:

20180316535, Nov 1, 2018

Filed:

Jul 9, 2018

Appl. No.:

16/029967

Inventors:

- Plano TX, US
Tao Ouyang - Santa Clara CA, US
Dao Pan - Santa Clara CA, US
Xiaoshu Si - Santa Clara CA, US
Syed Rahman - Santa Clara CA, US

International Classification:

H04L 27/26
H04L 27/12
H04L 12/28
H04L 5/00
H04B 10/25
H04B 10/27
H04J 1/02

Abstract:

A central access network unit comprising a processor configured to assign a plurality of upstream training blocks from an upstream OFDM symbol to a plurality of downstream network units, wherein the OFDM symbol comprises a plurality of pilot subcarriers equally spaced across an upstream RF spectrum in a pre-determined time interval, and wherein each upstream training block comprises a different subset of the pilot subcarriers that are non-consecutive and situated across the upstream RF spectrum, and generate one or more messages comprising assignments of the upstream training blocks, and a transmitter coupled to the processor and configured to transmit the messages to the plurality of downstream network units via a network, wherein the messages instruct at least one of the plurality of downstream network units to transmit a modulated pre-determined sequence at the pilot subcarriers corresponding to the upstream training block assigned to the downstream network unit.

US Patent:

20170019283, Jan 19, 2017

Filed:

Sep 30, 2016

Appl. No.:

15/282157

Inventors:

- Plano TX, US
Tao Ouyang - Santa Clara CA, US
Dao Pan - Santa Clara CA, US
Xiaoshu Si - Santa Clara CA, US
Syed Rahman - Santa Clara CA, US

International Classification:

H04L 27/26
H04B 10/25
H04B 10/27
H04L 5/00
H04L 12/28

Abstract:

A central access network unit comprising a processor configured to assign a plurality of upstream training blocks from an upstream OFDM symbol to a plurality of downstream network units, wherein the OFDM symbol comprises a plurality of pilot subcarriers equally spaced across an upstream RF spectrum in a pre-determined time interval, and wherein each upstream training block comprises a different subset of the pilot subcarriers that are non-consecutive and situated across the upstream RF spectrum, and generate one or more messages comprising assignments of the upstream training blocks, and a transmitter coupled to the processor and configured to transmit the messages to the plurality of downstream network units via a network, wherein the messages instruct at least one of the plurality of downstream network units to transmit a modulated pre-determined sequence at the pilot subcarriers corresponding to the upstream training block assigned to the downstream network unit.