Patents by Inventor Krishna Balachandran

Krishna Balachandran has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20040160919
    Abstract: In a wireless communication system, there is a method of generating and transmitting signaling information from a user, where user control information may be appended as a header to a data block, and the data block and header may be encoded and transmitted as a signaling message from the user. In a method of scheduling a user for transmitting information, a signaling message, which may include user control information, is received from a user. A scheduling grant message that may include an allocated data rate may be transmitted in response to the received signaling message. The user control information may include one or more of buffer status information of the user, reverse pilot channel transmit power information and data related to a soft handoff (SHO) status of the user.
    Type: Application
    Filed: February 14, 2003
    Publication date: August 19, 2004
    Inventors: Krishna Balachandran, Arnab Das, Farooq Ullah Khan, Ashwin Sampath, Hsuan-Jung Su
  • Patent number: 6778558
    Abstract: A system and method for incremental redundancy transmission in a communication system. A time slot is provided having at least one sub-slot with a fixed size, and a data block sized to fit in the sub-slot, a header having a one data block sequence number in the header for the time slot. A parity block is sized smaller than the data block such that the parity block and the data block sequence number fit within the sub-slot. The data block and parity block are transmitted in the sub-slot within the time slot. In the header for the time slot the number of data blocks and parity blocks transmitted are identified.
    Type: Grant
    Filed: January 5, 1999
    Date of Patent: August 17, 2004
    Assignee: Lucent Technologies Inc.
    Inventors: Krishna Balachandran, Richard P. Ejzak, Sanjiv Nanda
  • Publication number: 20040085934
    Abstract: In the method, information from a user is transmitted over one or more communication channels of a wireless communication system by code multiplexing transmissions in the code domain. The method may include code multiplexing a first information from the user over a first channel with a second information from the user over a second channel, and determining a transmission format for the first and second channels. The transmission format may be determined based on one or more of available transmit power, transmission time interval, a coding dimension used for multiplexing, and transmit power used per code. The first information and second information are transmitted over the respective channels based on the determined transmission format.
    Type: Application
    Filed: November 1, 2002
    Publication date: May 6, 2004
    Inventors: Krishna Balachandran, Arnab Das, Ashwin Sampath, Hsuan-Jung Su
  • Publication number: 20040057501
    Abstract: An adaptive pulse position modulated CDMA scheme for use in UWB communications systems is disclosed. A stream of input bits is encoded with spreading code sequence. The spreading code sequence consists of a number of code elements that may have one of two values. Each bit is encoded into a symbol consisting of a predefined number of chips, which are transmitted during a symbol period. Next, at least one code element is associated with each chip in the symbol. Then, an encoded pulse is generated in each chip. Each encoded pulse has a value determined by multiplying the data bit with the code value associated with the particular chip. The encoded pulse is then pulse position modulated by shifting the position of the pulse to a first position or a second position within the chip depending upon the encoded value of the pulse.
    Type: Application
    Filed: September 23, 2002
    Publication date: March 25, 2004
    Inventors: Krishna Balachandran, Doru Calin, Tingfang Ji, Joseph H. Kang
  • Publication number: 20040057407
    Abstract: Methods and apparatuses for allocating control and data time slots to a plurality of wireless mobile stations in a wireless communication system using time division multiplexing. The methods and apparatuses assign such time slots by first placing the wireless mobile stations into a number of different groups. Then, control time slots and anchor data time slots are assigned to the groups in the uplink and downlink frames of a carrier such that the uplink control time slot for each group is maximally spaced in time relative to the downlink control time slot for the same group. Data time slots are subsequently assigned to a particular mobile station by assigning time slots in the uplink and downlink frames which are as close as possible to the group's uplink or downlink anchor data time slots, as the case may be, according to a “grow from center” technique.
    Type: Application
    Filed: September 24, 2002
    Publication date: March 25, 2004
    Inventors: Krishna Balachandran, Kirk K. Chang, Wei Luo, Sanjiv Nanda
  • Publication number: 20040057500
    Abstract: Methods and systems for generating a variable spacing pulse position modulated (VSPPM) signal for transmission across an ultra-wideband communications channel. The variable pulse position modulated spread spectrum signal is created by encoding every M input data bits from an input data stream into a symbol consisting of Nc chips. Each chip is divided into 2M sub-chips and each sub-chip is further divided into Np time slots. A pulse is transmitted for each chip in the symbol. During each chip period, the pulse is placed in the sub-chip corresponding to the binary M-tuple (or symbol) value. A time hopping code sequence consisting of Nc elements with a one-to-one chip association is then applied to each symbol so that the position of each pulse is shifted to the appropriate time slot that corresponds to the time hopping code value.
    Type: Application
    Filed: September 23, 2002
    Publication date: March 25, 2004
    Inventors: Krishna Balachandran, Doru Calin, Tingfang Ji, Joseph H. Kang
  • Publication number: 20030185181
    Abstract: A system and method for incremental redundancy transmission in a communication system. A time slot is provided having at least one sub-slot with a fixed size, and a data block sized to fit in the sub-slot, a header having a one data block sequence number in the header for the time slot. A parity block is sized smaller than the data block such that the parity block and the data block sequence number fit within the sub-slot. The data block and parity block are transmitted in the sub-slot within the time slot. In the header for the time slot the number of data blocks and parity blocks transmitted are identified.
    Type: Application
    Filed: January 5, 1999
    Publication date: October 2, 2003
    Inventors: KRISHNA BALACHANDRAN, RICHARD P. EJZAK, SANJIV NANDA
  • Patent number: 6625133
    Abstract: A system and method of implementing a radio link protocol and dynamic partial echo management for a transaction oriented packet data communication system. A data backlog is described with a media access control layer controller and transmitting a BEGIN protocol data unit transmitted to a receiver. A media access control layer transaction is initiated in response to the transmitting of the BEGIN frame.
    Type: Grant
    Filed: March 31, 1999
    Date of Patent: September 23, 2003
    Assignee: Lucent Technologies Inc.
    Inventors: Krishna Balachandran, Richard P. Ejzak, Sanjiv Nanda, Shiv M. Seth, Stanley Vitebsky, William Waung
  • Patent number: 6611515
    Abstract: A system and method of implementing a radio link protocol completion oriented packet data communication system. A data backlog is described with a media access control layer controller and transmitting a BEGIN protocol data unit containing a flag transmitted to a receiver. A media access control layer transaction is initiated in response to the transmitting of the BEGIN protocol data unit.
    Type: Grant
    Filed: April 5, 1999
    Date of Patent: August 26, 2003
    Assignee: Lucent Technologies Inc.
    Inventors: Krishna Balachandran, Richard P. Ejzak, Sanjiv Nanda, Shiv M. Seth, Stanley Vitebsky, William Waung
  • Patent number: 6567375
    Abstract: Unlike earlier methods and systems in which Radio Link Control (RLC) performance was characterized in terms of the throughput, and the size of the higher layer Protocol Data Units (PDUs) or packets to be transferred was ignored, a method and apparatus is provided that is based on the delay of a higher layer PDU or packet. A method and apparatus so based have less delay than a method and apparatus based on employing adaptive coding and modulation to achieve the greatest mean throughput of a data block.
    Type: Grant
    Filed: December 29, 2000
    Date of Patent: May 20, 2003
    Assignee: Lucent Technologies Inc.
    Inventors: Krishna Balachandran, Kirk K Chang, Richard Paul Ejzak, Wei Luo, Sanjiv Nanda
  • Patent number: 6557135
    Abstract: A system includes a generator component that determines a plurality of portions that comprise an entirety of error-indicating acknowledgement information. The system includes a generator component that cycles through the plurality of portions that comprise the entirety of the error-indicating acknowledgement information to send the error-indicating acknowledgement information.
    Type: Grant
    Filed: May 17, 2000
    Date of Patent: April 29, 2003
    Assignee: Lucent Technologies Inc.
    Inventors: Krishna Balachandran, Richard P. Ejzak, Sanjiv Nanda
  • Patent number: 6532222
    Abstract: Demodulator assignment logic is provided that confirms the presence and quality of a multipath before assigning a parallel demodulator to that multipath. Multipath presence and quality are confirmed when at least two power measurements of a multipath at least equal a selectable power threshold. Before permitting demodulated data from an assigned demodulator to be processed, demodulator assignment logic further reconfirms the presence and quality of a multipath via another more reliable power measurement that at least equals another selectable power threshold.
    Type: Grant
    Filed: November 5, 1998
    Date of Patent: March 11, 2003
    Assignee: Lucent Technologies Inc.
    Inventors: Kiran Meghashyam Rege, Krishna Balachandran, Kirk Kuokuang Chang, Zhendong Cao, Abdulkadir Dinc, Yogendra Champaklal Shah
  • Publication number: 20020164990
    Abstract: A wireless endpoint employs frequency hopping for communicating signals in a wireless communications system. Over a time period T, the wireless endpoint performs pseudo-random selection of a frequency from a hopping set of N frequencies such that over at least a portion of the time period T, the frequency selection is constrained to less than the N frequencies.
    Type: Application
    Filed: May 7, 2001
    Publication date: November 7, 2002
    Inventors: Krishna Balachandran, Joseph H. Kang, Kumud K. Sanwal, James Paul Seymour
  • Publication number: 20020036992
    Abstract: Unlike earlier methods and systems in which Radio Link Control (RLC) performance was characterized in terms of the throughput, and the size of the higher layer Protocol Data Units (PDUs) or packets to be transferred was ignored, a method and apparatus is provided that is based on the delay of a higher layer PDU or packet. A method and apparatus so based have less delay than a method and apparatus based on employing adaptive coding and modulation to achieve the greatest mean throughput of a data block.
    Type: Application
    Filed: December 29, 2000
    Publication date: March 28, 2002
    Inventors: Krishna Balachandran, Kirk K. Chang, Richard Paul Ejzak, Wei Luo, Sanjiv Nanda
  • Publication number: 20020019232
    Abstract: In a mobile station-mobile receiver arrangement a method and apparatus for a radio link control (RLC) protocol that allows partial recovery of data for streaming services. The maximum number of retransmissions allowed by the method for each RLC block is a function of the maximum delivery delay required by the streaming service and the round trip delay.
    Type: Application
    Filed: May 2, 2001
    Publication date: February 14, 2002
    Inventors: Krishna Balachandran, Kirk K. Chang, Richard Paul Ejzak, Wei Luo, Sanjiv Nanda
  • Patent number: 6215827
    Abstract: A system and method to measure channel quality in terms of signal to interference plus noise ratio for the transmission of coded signals over fading channels in a communication system. A Viterbi decoder metric for the Maximum Likelihood path is used as a channel quality measure for coherent and non-coherent transmission schemes. This Euclidean distance metric is filtered in order to smooth out short term variations. The filtered or averaged metric is a reliable channel quality measure which remains consistent across different coded modulation schemes speeds. The filtered metric is mapped to the signal to interference plus noise ratio per symbol using a threshold based scheme. Use of this implicit signal to interference plus noise ratio estimate is used for the mobile assisted handoff in a cellular system, power control and data rate adaptation in the transmitter.
    Type: Grant
    Filed: March 19, 1998
    Date of Patent: April 10, 2001
    Assignee: Lucent Technologies, Inc.
    Inventors: Krishna Balachandran, Sanjiv Nanda, Srinivas R. Kadaba, Richard P. Ejzak
  • Patent number: 6108374
    Abstract: A system and method to measure channel quality in terms of signal to noise ratio for the transmission of coded signals over fading channels. A Viterbi decoder metric for the Maximum Likelihood path is used as a channel quality measure. This Euclidean distance metric is filtered in order to smooth out short term variations. The filtered or averaged metric is a reliable channel quality measure which remains consistent across different coded modulation schemes and at different mobile speeds. The filtered metric is mapped to the signal to noise ratio per symbol using a threshold based scheme. Use of this implicit signal to noise ratio estimate is used for the mobile assisted handoff and data rate adaptation in the transmitter.
    Type: Grant
    Filed: August 25, 1997
    Date of Patent: August 22, 2000
    Assignee: Lucent Technologies, Inc.
    Inventors: Krishna Balachandran, Sanjiv Nanda, Srinivas R. Kadaba, Richard P. Ejzak
  • Patent number: 6052566
    Abstract: A wireless receiver includes a variable attenuator, a signal-to-noise ratio (SNR estimator), and a received signal strength indicator (RSSI) level detector. The RSSI level of the received signal is used as a primary criterion on setting the attenuator status. Once the attenuator is set based upon the RSSI readings, an SNR check is made to determine the possible presence of IM. Then, further adjustment on the attenuator status is made according to the SNR check.
    Type: Grant
    Filed: June 26, 1998
    Date of Patent: April 18, 2000
    Assignee: Lucent Technologies Inc.
    Inventors: Victor Alexander Abramsky, Krishna Balachandran, Kirk Kuokuang Chang, Kiran M. Rege