Kumar Jayanthi Balachandran

6366624, Apr 2, 2002

Nov 30, 1998

09/201651

Kumar Balachandran - Cary NC
Ali Khayrallah - Apex NC

Ericsson Inc. - Research Triangle Park NC

H03M 1341

375341, 375262, 375265, 375267, 375342, 714792, 714794, 714795, 714798

Methods and systems are provided for receiving a modulated signal including symbols representing both encoded and unencoded bits from a data (e. g. , speech) frame where a received slot is first demodulated and the encoded bits are decoded. The decoded bits are then utilized to constrain demodulation during a second demodulation of a received slot. The encoded bit positions from the constrained second demodulation are, in turn, encoded to generate bit estimates for the received slot. This information is combined with the output of the constrained second demodulation for unencoded bits to provide a received data frame estimate which has been shown to have improved reliability for both encoded and unencoded bits. The methods and systems further provide for recursively repeating the demodulation and decoding steps until a counter expires or a desired reliability is obtained.

6463450, Oct 8, 2002

Aug 26, 1999

09/384111

Kumar Balachandran - Cary NC
Havish Koorapaty - Cary NC

Ericsson Inc. - Research Triangle Park NC

G06F 1717

708300, 708207

A method and apparatus for determining the location of the peak of a signal using an adaptive filter bank. The method includes the steps of providing a set of calculated output points for the function using a predetermined calculation interval. A maximum output point of the set is then determined, and the output points of the function are interpolated within the region of the maximum. A maximum of the interpolated output points approaches the peak of the function. The apparatus includes a plurality of interconnected digital filters operating on the function to calculate output values, and at least one control unit in communication with the digital filters. The control unit is operable to control the output of the filters and to select a first maximum of the output values. The control unit allows progressive interpolation of output values surrounding the first maximum to determine whether the interpolated output values approach a peak.

6483828, Nov 19, 2002

Feb 10, 1999

09/248506

Kumar Balachandran - Cary NC
Rajaram Ramesh - Cary NC
Havish Koorapaty - Raleigh NC
Eric Wang - Cary NC
Sandeep Chennakeshu - Cary NC
Amer Hassan - Kirkland WA

Ericsson, Inc. - Research Triangle Park NC

H04B 7216

370342, 370441, 370474

A system and method for permitting variable information rates and improved error performance using orthogonal or near-orthogonal codes is disclosed. This is achieved by simultaneously transmitting two or more Walsh code words from a given orthogonal code set and/or by transmitting multiple shorter orthogonal codewords sequentially such that their combined length equals the original codeword. It should be emphasized that the present invention can be used with any orthogonal or near-orthogonal code set.

6490314, Dec 3, 2002

Sep 23, 1998

09/158996

Ali S. Khayrallah - Apex NC
Kumar Balachandran - Cary NC

Ericsson Inc. - Research Triangle Park NC

H04B 1713

375132, 375131

The present invention relates to methods and systems for wireless communication wherein a plurality of narrowband carrier frequencies is overlaid with at least one wideband carrier frequency. In particular, the present invention relates to maintaining radio communication on the narrowband carrier frequencies closest to the edge of the bandwidth of the wideband carrier frequency in order to reduce system interference. This is accomplished by using frequency hopping to preferentially switch radio communication to narrowband carrier frequencies closest to the edge of the bandwidth of the wideband carrier frequency. Thus, the present invention discloses systems and methods which allow several communication devices to occupy the same frequency spectrum while maintaining interference at acceptable levels.

6608828, Aug 19, 2003

Sep 15, 1999

09/396145

Kumar Balachandran - Cary NC

Ericsson Inc. - Research Triangle Park NC

H04J 324

370349, 370392, 370477

A header that is repeatedly transmitted and received, along with data, on a radio channel is decoded by initially decoding at least one initially received header to identify values for the header fields. The header fields include invariant header fields having determinate values and changing header fields having changing values. At least one subsequently received header is decoded using the determinate values for at least one of the invariant header fields, thereby allowing increased reliability decoding of at least one of the changing header fields. The subsequent decoding can use predictive decoding using a probability value of unity for symbols associated with at least one of the invariant header fields. Headers also may be decoded by repeatedly transmitting a first header including invariant header fields and changing header fields, along with data, over a radio channel during a persistent flow communication session. Upon successful decoding of a first header, the second header is repeatedly transmitted that includes the changing header fields but excludes at least one of the invariant header fields.

6694146, Feb 17, 2004

Sep 27, 1995

08/534855

Carl Thomas Hardin - Encinitas CA, 92024
James E. Petranovich - Encinitas CA, 92024
Kumar Balachandran - Cary NC, 27511
Andrew Wright - Vancouver, BC, VG4 IJ9, CA

H04B 700

455515, 4553431

Energy expenditure is reduced in a wireless subscriber station operating in a Cellular Digital Packet Data (CDPD) system by deleting the operation of decoding the Forward Error Correction (FEC) blocks. The decoding of the FEC blocks can be deleted by virtue of using opening and closing Temporary Equipment Identifier (TEI) messages having a minimum hamming distance from all the other TEI messages. Base Error Rate (BER) is measured to determine when the necessity of decoding an FEC block exists. By limiting this operation, battery life for wireless subscriber stations is prolonged.

6898195, May 24, 2005

May 9, 2000

09/568452

Johan Molnö - Bromma, SE
Kumar Balachandran - Cary NC, US
Christofer Lindheimer - Kista, SE

Telefonaktiebolaget LM Ericsson (publ) - Stockholm

H04Q007/00

370329, 370437

In a packet switched system used for speech communication, a user entering a silent period, start to transmit silence descriptor information (SID). According to the invention, a speech user is not allocated the same resources for transmission of SID as for the speech communication. Instead, the user is, upon entering a silent period, reallocated to a SID communication channel, shared between a number of different users in silent mode. The resources used for speech may then be more advantageously utilized for other speech users, and is not occupied for SID transmissions only. In an alternate embodiment of the invention, when a mobile station is in silent mode, it receives and transmits associated signaling information on the same transmission resources as those used for the SID transmissions.

7142580, Nov 28, 2006

Oct 24, 2000

09/695357

Kumar Balachandran - Cary NC, US
Rajaram Ramesh - Cary NC, US

Ericsson, Inc. - Research Triangle Park NC

H04B 1/713

375132

A mobile terminal and a base station subsystem may communicate by assigning a primary or control frequency to the cell in which the mobile terminal is located and using that control frequency to exchange control information between the mobile terminal and the base station subsystem. The exchange of control information in the cell is constrained to the primary or control frequency. In addition, a plurality of traffic frequencies may be assigned to the cell and used to exchange traffic information between the mobile terminal and the base station subsystem using coordinated frequency hopping. Multi-path fading experienced on diverse, non-contiguous traffic frequency bands may be uncorrelated between the respective bands. Consequently, a code-word carried over a plurality of non-contiguous frequencies may be more likely to experience random, uncorrelated fading, which may improve the signal to noise ratio (SNR) of the signal and, as a result, improve network performance.