Kris Kelkar

US Patent:

6345375, Feb 5, 2002

Filed:

Feb 24, 1999

Appl. No.:

09/257161

Inventors:

Kris Kelkar - Camarillo CA
David M. Stewart - Ventura CA

Assignee:

California Amplifier, Inc. - Camarillo CA

International Classification:

G08C 2502

US Classification:

714748, 714749, 714776

Abstract:

Packet-based communication methods and systems are provided which improve data throughput and which respond to different error-rate conditions with modifications appropriate for those conditions. In method embodiments, data frames are initially formed to each have N data packets and a frame error code. Data frames are then transmitted and checked. In response to the check, data packets of error-free data frames are routed through the system and data frames that are in error are retransmitted. The checking, processing and retransmitting steps are repeated until all data packets are routed through the communication system. In another method embodiment, data packets of each data frame found to be in error in the checking step are inserted into a data frame of the forming step. In a feedback feature, a system error rate is determined and, in response, N is periodically updated to a value that realizes the best throughput under the current noise condition of the transmission link.

US Patent:

6396803, May 28, 2002

Filed:

Mar 26, 2001

Appl. No.:

09/817657

Inventors:

James J. Hornsby - Newbury Park CA
Kris Kelkar - Camarillo CA

Assignee:

California Amplifier, Inc. - Camarillo CA

International Classification:

H04J 1100

US Classification:

370208, 370343, 370482

Abstract:

Wireless communication methods and structures are provided that enhance communication robustness while reducing cost. They communicate downstream data with orthogonal frequency division multiplexing (OFDM) transmission processes and upstream data with single carrier transmission processes. This combination of transmission processes is configured with various signal modulations (e. g. , quadrature phase shift keying (QPSK), m-ary phase shift keying (MPSK) and n-quadrature amplitude modulation (QAM)) to provide lower cost upstream communication from customer services equipments (CPEs) and more robust downstream communication from headends than has been achieved in conventional communication systems. Signal diversity is enhanced by receiving communication signals with multiple antennas that are spatially separated and have different polarizations to thereby enhance frequency diversity. Signal diversity is further enhanced by combining the received signals in ways that maximize the ratio of desired to undesired signals.

US Patent:

6553209, Apr 22, 2003

Filed:

Sep 5, 2000

Appl. No.:

09/655497

Inventors:

James J. Hornsby - Newbury Park CA
Kris Kelkar - Camarillo CA

Assignee:

California Amplifier, Inc. - Camarillo CA

International Classification:

H04B 140

US Classification:

455 76, 455260, 375376

Abstract:

Local-oscillator systems for wireless communication systems are realized with oscillator networks that are phase locked to a bit timing clock. Two of the networks provide first and second phase coherent local-oscillator signals respectively to a receiver and transmitter of a transceiver. A third oscillator system forms a phase lock loop about one of the other networks and preferably includes a crystal to enhance short term stability. Because they track the bit timing clock, the first and second local-oscillator signals phase track all communication signals in the transceivers communication system.

US Patent:

6947507, Sep 20, 2005

Filed:

Nov 20, 2001

Appl. No.:

09/989337

Inventors:

Kris Kelkar - Camarillo CA, US
Anand Kelkar - Calabasas CA, US

Assignee:

Calamp Corp. - Oxnard CA

International Classification:

H04L001/02
H04L027/14

US Classification:

375347, 375316

Abstract:

Receiver systems and methods are provided for processing transmit signals Sthat are received over a receive channel Cwhich is formed by a plurality of receive paths. Method embodiments comprise the steps of a) receiving the transmit signals Swith a plurality of spatially separated antennas to form respective receive signals S, and b) spatially and temporally processing the receive signals Sto form a combined corrected signal Sthat reduces errors in at least one signal parameter. Exemplary signal parameters include signal preambles, codes, spreading codes and modulations.

US Patent:

7009573, Mar 7, 2006

Filed:

Aug 12, 2003

Appl. No.:

10/640224

Inventors:

James J. Hornsby - Newbury Park CA, US
Gary G. Sanford - Camarillo CA, US
Kris Kelkar - Camarillo CA, US
Shawn Aleman - Camarillo CA, US

Assignee:

Calamp Corp. - Oxnard CA

International Classification:

H01Q 13/10
H01B 7/14

US Classification:

343770, 343767, 343727, 455 15, 455 16

Abstract:

Compact bidirectional repeaters are provided for wireless communication systems. Their compact size is realized with repeater structures that include different-polarization antennas, back lobe suppressing structures, circuit feedback paths, antenna-feedback detectors, and automatic gain control.

US Patent:

7035652, Apr 25, 2006

Filed:

Jan 23, 2004

Appl. No.:

10/764077

Inventors:

Kris Kelkar - Camarillo CA, US

Assignee:

Calamp Corp. - Oxnard CA

International Classification:

H04Q 7/20

US Classification:

4554566, 4554561, 455 634, 4554521, 455 65, 4555621, 455504, 455506

Abstract:

Wireless communication structures and methods are provided that enhance range and performance via managed access to a wireless communication medium between system clients. The access is configured to maintain the low equipment costs and widespread equipment availability of standards-based communication systems. In particular, the structures include at least one antenna, a processor that spatially processes receive signals from the antenna, a media access controller that compares the age of receive location information with a predetermined time coherence, a location-information transformer that transforms the receive location information into transmit location information, and a transmit spatial processor configured to provide a transmit signal to the antenna that is spatially processed in accordance with the transmit location information if the age is less than the time coherence and spatially processed in accordance with predetermined location information if the age exceeds the time coherence. A database is preferably provided for storage of the receive location information and the age.

US Patent:

7072693, Jul 4, 2006

Filed:

Apr 23, 2003

Appl. No.:

10/422411

Inventors:

Charles S. Farlow - Waconia MN, US
Kris Kelkar - Camarillo CA, US

Assignee:

CalAmp Corp. - Oxnard CA

International Classification:

H04M 1/00

US Classification:

4555621, 455 69, 370334, 375299

Abstract:

Wireless communications structures and methods are provided that utilize frequency domain spatial processing. Structure is included that receives and transmits signals from an array of Mβ antennas wherein the antennas are connected to M switches in groups of β. Each switch is connected to a single spatial processing channel and β antennas and each spatial processing channel is assigned complex multiplicative factor(s), or weight(s), that enhance overall system performance in the presence of interference and propagation-related impairments such as multipath fading.

US Patent:

7085306, Aug 1, 2006

Filed:

Oct 30, 2001

Appl. No.:

10/013321

Inventors:

Mikhail Voldman - Northbrook IL, US
Dan Budinger - Arlington Heights IL, US
Ali Akgun - Chicago IL, US
John G. Fijolek - Naperville IL, US
Mark O. Vogel - Hampshire IL, US
Kris Kelkar - Camarillo CA, US

Assignee:

3Com Corporation - Marlborough MA

International Classification:

H04B 1/713

US Classification:

375132, 375133, 370431, 370436, 370341, 370329

Abstract:

System and method for providing a multi-frequency upstream transmission channel to a network device. When a headend network entity generates an upstream channel descriptor message, the descriptor message includes at least two upstream frequencies available for upstream transmission, and a frequency hopping descriptor with a frequency-hopping pattern associated with the available frequencies for determining an upstream frequency for upstream transmission. The headend provides a timing reference for determining upstream transmission periods on the frequencies available on the network device. When the headend receives upstream transmission on one of the available upstream frequencies, the headend network entity determines frequency distortions. If the distortions exceed a threshold level, the headend may send a new upstream channel descriptor message that excludes the upstream frequency associated with the high frequency distortions, add a new upstream frequency, or defines a new frequency-hopping pattern.