Patents by Inventor Sarath Kumar
Sarath Kumar 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).
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Patent number: 7193981Abstract: In the method of processing soft handoff information at a base station, soft handoff information of a mobile station is received at the base station. The soft handoff information indicates at least a number of base stations in an active list of the mobile station. The active list is a list of base stations involved in a call of the mobile station. The base station applies a rules set to the soft handoff information to determine changes in the active list. The rules set requires more stringent conditions be met to add a base station to the active list when the active list includes a first number of base stations as compared to when the active list includes a second number of base stations; wherein the first number is greater than the second number. The determination results are then sent to the mobile station.Type: GrantFiled: July 25, 2000Date of Patent: March 20, 2007Assignee: Lucent Technologies Inc.Inventors: Walid Ahmed, Joe Huang, Sarath Kumar, Sanjiv Nanda, Devesh T. Patel, Melanie M. Wang
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Patent number: 6952561Abstract: A universal mobile telecommunications system (UMTS) receiver uses Pilot Symbol Assisted Modulation (PSAM) in demodulating a received Binary Phase Shift Keying (BPSK) signal. The UMTS receiver uses a ratio of the transmitted energy per pilot symbol to the transmitted energy per data symbol as an index into a look-up table to return a value for a scale factor for use in demodulation of the received signal, which provides better performance during periods when the fading distribution is unknown.Type: GrantFiled: August 31, 2000Date of Patent: October 4, 2005Assignee: Lucent Technologies Inc.Inventors: Sarath Kumar, Pantelis Monogioudis, Kiran M Rege, Ashwin Sampath
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Publication number: 20050108241Abstract: The present invention relates to a method for designing networks, more particularly to a method for designing lost cost static telecommunication networks (101) with failure protection (404), which results in an efficient utilization of network elements (nodes) and transmission links (Links).Type: ApplicationFiled: October 4, 2001Publication date: May 19, 2005Applicant: Tejas Networks India Pvt. Ltd.Inventors: Krishna Depura, Sarath Kumar, Amit Agrawal, Sanjay Patnaik
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Patent number: 6782261Abstract: In a wireless communication system, in which a mobile station is operable to monitor the signal strengths of a plurality of pilot signals transmitted from a plurality of base stations, a method and device by which the mobile station determines the membership of Active Set pilots by generating a quality metric derived as a function of (i) detected pilot signal strengths corresponding to the Active Set of pilots, and (ii) detected pilot signal strengths corresponding to a non-Active Set of pilots, determining a threshold value, the threshold value determined as a function of the quality metric, and assigning the pilot to, or removing the pilot from, the Active Set of pilots if the signal strength corresponding to the pilot exceeds the threshold value.Type: GrantFiled: April 27, 2000Date of Patent: August 24, 2004Assignee: Lucent Technologies Inc.Inventors: Walid Ahmed, Sarath Kumar, Sanjiv Nanda
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Patent number: 6757270Abstract: A back haul architecture effectively reduces the reactivation times for both forward-link and reverse-link data transmissions over CDMA wireless communications systems, by relying on packet-mode transmissions over the back haul between a frame selection/distribution (FSD) function and the appropriate base stations. In particular, for the forward direction, the FSD function transmits forward-link data only to one base station, which is solely responsible for controlling the forward-link air interface with the corresponding mobile unit. For the reverse direction, each base station that receives frames of reverse-link data from the mobile unit, assigns a time tag to the frame, divides the frame into one or more data packets, assigns a different sequence number to each data packet, and transmits the data packets to the FSD function over the back haul, all without first synchronizing time with any other base station that is also operating in reverse-link soft hand-off with that mobile unit.Type: GrantFiled: June 11, 1999Date of Patent: June 29, 2004Assignee: Lucent Technologies Inc.Inventors: Sarath Kumar, Sanjiv Nanda, Harvey Rubin, Stanislav Vitebskiy
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Patent number: 6654422Abstract: A variable length sequence number is used to identify data units in a communication channel. The sequence number associated with the most recent data that has been received successfully and the sequence number expected with the next new data message to be received are examined to determine the minimum size sequence number necessary to unambiguously identify to the transmitter incorrectly received data that must be retransmitted in a later message. The receiver provides the transmitter with the sequence number associated with the last successfully received byte of data and the sequence number associated with the next expected byte of data. The receiver communicates this information to the transmitter using a NAK control message.Type: GrantFiled: May 14, 1999Date of Patent: November 25, 2003Assignee: Lucent Technologies Inc.Inventors: Farooq Ullah Khan, Douglas N. Knisely, Sarath Kumar, Kameswara Rao Medapalli, Sanjiv Nanda
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Patent number: 6507568Abstract: A mobile communications system employs extended channel assignment messaging during the call setup portion of a mobile call. As part of the call setup process, a mobile station sends an access request message to a primary base station that includes a list of alternate base stations. As call setup continues, the mobile station employs diversity reception in monitoring the paging channel of three base stations, each selected as a function of the strength of the signal-to-noise ratios of their respective pilot tones.Type: GrantFiled: August 27, 1997Date of Patent: January 14, 2003Assignee: Lucent Technologies Inc.Inventors: Sarath Kumar, Wen-Yi Kuo, Kiran M. Rege
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Patent number: 6507572Abstract: A back haul architecture enables efficient primary transfer (i.e., transfer of the designation of primary base station from one base station to another). A frame selection/distribution (FSD) function queues packets of forward-link data—to which sequence numbers have been assigned—for packet-mode transmission over the back haul only to one base station—the current primary base station—where the packets are again queued for over-the-air transmission to the mobile unit. If and when it becomes appropriate to transfer the designation of primary base station to another base station, there may still be packets of data queued at the old primary base station awaiting transmission to the mobile unit. The old primary base station sends a message to the new primary base station indicating a particular sequence number that identifies the remaining packets of forward-link data queued at the old primary base station.Type: GrantFiled: June 11, 1999Date of Patent: January 14, 2003Assignee: Lucent Technologies Inc.Inventors: Sarath Kumar, Sanjiv Nanda, Harvey Rubin, Stanislav Vitebskiy
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Patent number: 6434367Abstract: In a wireless communications system, a base station transmits power control signals (e.g., the power control bits of a power control sub-channel) to a mobile using a forward-link channel that is decoupled from all other signals transmitted from that base station to that mobile. For example, the decoupled forward-link channel may be a common power control channel. The mobile then uses the power control signals received in the decoupled forward-link channel to control its power level for transmitting one or more reverse-link channels to the base station. The ability of base stations to use decoupled forward-link channels in order to transmit their power control signals to a mobile enables a mobile to operate with different active sets for the forward and reverse links. This enables forward-link data traffic to be implemented using a simplex mode, even when the mobile is operating in soft handoff in the reverse link.Type: GrantFiled: June 11, 1999Date of Patent: August 13, 2002Assignee: Lucent Technologies Inc.Inventors: Sarath Kumar, Quinn Li, Xiao C. Wu
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Patent number: 6418148Abstract: Bursts of additional bandwidth (e.g., one or more supplemental channels or a channel having variable bandwidth) is assigned to users (e.g., high-speed data users) in a cellular telecommunication system. A request for assignment of additional bandwidth may be an initial request, a continuation request for an on-going burst, or a retry request after a previously rejected request. In any case it is determined whether to grant or reject the request. If the request is rejected, instructions are given to submit a retry request after a specified backoff time. The present invention may be implemented using either an asynchronous approach or a synchronous approach. According to the asynchronous approach, all requests are handled asynchronously. According to the synchronous approach, initial requests are handled asynchronously, but continuation requests and retry requests are handled synchronously at epoch times that coincide with specific time slots.Type: GrantFiled: July 23, 1998Date of Patent: July 9, 2002Assignee: Lucent Technologies Inc.Inventors: Sarath Kumar, Sanjiv Nanda, Stanislav Vitebskiy
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Publication number: 20010043578Abstract: A mobile communications system employs extended channel assignment messaging during the call setup portion of a mobile call. As part of the call setup process, a mobile station sends an access request message to a primary base station that includes a list of alternate base stations. As call setup continues, the mobile station employs diversity reception in monitoring the paging channel of three base stations, each selected as a function of the strength of the signal-to-noise ratios of their respective pilot tones.Type: ApplicationFiled: August 27, 1997Publication date: November 22, 2001Inventors: SARATH KUMAR, WEN-YI KUO, KIRAN M. REGE
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Patent number: 6212399Abstract: A technique for controlling the power with which a wireless terminal transmits is disclosed. One embodiment of the present invention comprises: transmitting a first signal at a first power level; receiving a series of n power control signals, bi−n+1 through bi; setting a step size based on a measure of dispersion of the n power control signals; and transmitting a second signal at a second power level that is based on the first power level and the step size.Type: GrantFiled: March 6, 1998Date of Patent: April 3, 2001Assignee: Lucent Technologies, Inc.Inventors: Sarath Kumar, Sanjiv Nanda, Lei Song
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Patent number: 6097954Abstract: The present invention increases the success rate of soft handoffs by enhancing the ability of a mobile-telephone to receive a handoff direction message that identifies the traffic channel being assigned to enable a candidate base station to communicate with the mobile-telephone. Specifically, the aforementioned ability of the mobile-telephone is enhanced by using the candidate base station to transmit the handoff direction message on a communication channel belonging to the candidate base station and being listened to by the mobile-telephone. In situations where signals transmitted from active set base stations have a low signal-to-noise ratio at the mobile-telephone, signals transmitted from the candidate base station may have a higher signal-to-noise ratio at the mobile-telephone.Type: GrantFiled: August 29, 1997Date of Patent: August 1, 2000Assignee: Lucent Technologies, Inc.Inventors: Sarath Kumar, Wen-Yi Kuo, Kiran M. Rege
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Patent number: 6088335Abstract: A code division multiple access system provides a way of allocating an increased data rate to a requesting mobile station. A mobile station requesting a data rate in excess of the basic data rate sends received pilot strength data for its base station and base stations in adjacent cells. The received pilot strength data is used to determine an increased data rate to be assigned to the requesting mobile station. One feature assigns an increased data rate based on the difference in the maximum received received pilot strength data from a non-active base station (one not in connection with the mobile station) and the maximum received pilot strength data from an active base station (one in connection with the mobile station). Yet another feature utilizes a series of threshold levels, each pair of levels associated with a different permitted data rate. Using the received pilot strength data, a data rate is determined which satisfies all adjacent cell interference concerns.Type: GrantFiled: April 21, 1997Date of Patent: July 11, 2000Assignee: Lucent Technologies Inc.Inventors: Chih-Lin I, Sarath Kumar, Sanjiv Nanda
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Patent number: 6073021Abstract: A method for increasing the success rate for soft handoffs, particularly under rapidly fluctuating fading conditions, using traffic channels of active set base stations. In one embodiment of the present invention, increased success rate for soft handoffs is achieved using a candidate base station, in addition to the active set base stations, to transmit a handoff command message to the mobile-telephone. Specifically, the handoff command message is transmitted by the active set base stations over the traffic channels assigned to mobile-telephone for communicating with the active set base stations, and by the candidate base station over the traffic channel assigned to the mobile-telephone for communicating with a primary base station. Additionally, a pilot signal may be transmitted by the candidate base station to enable the mobile-telephone to coherently demodulate the handoff direction message transmitted by the candidate base station.Type: GrantFiled: May 30, 1997Date of Patent: June 6, 2000Assignee: Lucent Technologies, Inc.Inventors: Sarath Kumar, Wen-Yi Kuo, Kiran M. Rege
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Patent number: 6069883Abstract: A code division multiple access system method and apparatus provides for allocation of increased bandwidth to a requesting mobile station. An access controller receives a data burst request (from either a requesting mobile station or from an external network already in connection with the mobile station) requesting a first data rate in excess of the basic data rate B allocated to a mobile station of a first cell. The access controller determines an increased data rate which is to be granted to said mobile station without causing excessive interference at said first cell and at least one adjacent cell and transmits a data burst assignment to a base station of said first cell indicating the increased data rate which has been granted to said mobile station.Type: GrantFiled: April 8, 1997Date of Patent: May 30, 2000Assignee: Lucent Technologies IncInventors: Richard Paul Ejzak, Subhasis Laha, Sarath Kumar, Douglas Knisely, Sanjiv Nanda, Chih-Lin I