Patents by Inventor Prathima Agrawal
Prathima Agrawal 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).
-
Patent number: 6208864Abstract: A cellular-fixed call forwarding service is effected by introducing a Fixed-Cellular Mobility Agent (FCMA) into the cellular network, the FCMA having the functionality of a PSTN central office/CN mobile switching center for interconnecting incoming calls to the MSC as outgoing calls to the CN or the PSTN and which, in addition, monitors each call connection to carry out call forwarding between the CN and the PSTN. The PSTN and the CN are both provided locally by the same service provider.Type: GrantFiled: December 30, 1998Date of Patent: March 27, 2001Assignee: Telcordia Technologies, Inc.Inventors: Prathima Agrawal, Parameswaran Ramanathan
-
Patent number: 6188905Abstract: Intelligent allocation of wireless resources can help avoid the problems of dropped calls in a mobile communications network. A service for allocating resources is designed to develop profiles of subscribers' mobility. That is, profiles are developed for routes, traveled by subscribers at certain days and times. For example, some subscribers commute to and from work at relatively fixed times. By compiling this information in the profile and tracking the movement of the subscriber, the mobile network can anticipate the subscriber's movement into a next cell. Thus, wireless resources in the next cell can be reserved prior to the anticipated handover of an ongoing call involving the subscriber. Thus, uninterrupted service can be maintained and dropped calls can be avoided.Type: GrantFiled: September 30, 1997Date of Patent: February 13, 2001Assignee: AT&T Corp.Inventors: Ashok N. Rudrapatna, Dharma P. Agrawal, Prathima Agrawal
-
Patent number: 6108316Abstract: A method adapts scheduling priorities in a wireless communications system to conserve battery power in mobile terminals operating within the system. A base station, within the system, receives battery power level information and other setup information from mobile terminals operating within the service area of the base station during call setup procedures. Based on the battery power level information and other setup information, the base station adapts scheduling priorities for the mobile terminals to expedite wireless transmissions from those mobile terminals reporting low battery power levels.Type: GrantFiled: July 25, 1997Date of Patent: August 22, 2000Assignee: AT & T CorpInventors: Prathima Agrawal, Krishna M. Sivalingam, Mani Bhushan Srivastava
-
Patent number: 6075777Abstract: The invention relates to a dynamic channel allocation system for a mobile communication system wherein mobile units communicate with the base station on allotted channels. The channel allocations are determined according to a framework of network flows including flow paths with nodes representing active mobile units, base stations and channels used for communication between active mobile units and their respective base stations. A new call from a mobile unit is added by finding the shortest available augmenting path for the added unit. The edges between nodes can include cost and capacity factors which can be used to determine desirable reconfigurations for the network.Type: GrantFiled: August 21, 1996Date of Patent: June 13, 2000Assignee: Lucent Technologies Inc.Inventors: Prathima Agrawal, Balakrishnan Narendran, Narayanan Shivakumar
-
Patent number: 6072809Abstract: A method is disclosed for maintaining and updating statistical trends of network delay to provide a predictive approach to synchronization. Necessary information, such as timing and stream ID information, is gathered from streams of data and future network delay values are predicted by constructing a measured packet-delay distribution curve. In a preferred embodiment, the inventive system maintains a delay histogram with a discrete set of quantization bins, each storing the relative frequency with which a particular delay value is expected to occur among the arriving packets. The histogram is then used to approximate the distribution in the form of a curve.Type: GrantFiled: August 14, 1997Date of Patent: June 6, 2000Assignee: Lucent Technologies, Inc.Inventors: Prathima Agrawal, Balakrishnan Narendran, Cormac Sreenan
-
Patent number: 6072784Abstract: A method adapts scheduling priorities in a CDMA wireless communications system to conserve battery power in mobile terminals operating within the system. A base station, within the system, receives battery power level information and other setup information from mobile terminals operating within the service area of the base station during call setup procedures. Based on the battery power level information and other setup information, the base station adapts scheduling priorities for the mobile terminals to expedite wireless transmissions from those mobile terminals reporting low battery power levels. The base station schedules the transmissions from low battery power mobile stations to be clustered together in a low-power time slot which is separate in time from the scheduled transmissions from high battery power mobile stations.Type: GrantFiled: July 25, 1997Date of Patent: June 6, 2000Assignee: AT&T Corp.Inventors: Prathima Agrawal, Jyh-Cheng Chen, Shalinee Kishore, Krishna M. Sivalingam
-
Patent number: 6072990Abstract: A method and system for adaptively determining an operating point for a transmitter-receiver pair in a wireless communication network. The receiver receives data over an uplink and measures an average observed word error rate avg.sub.-- WER of the received data and transmits the average observed word error rate avg.sub.-- WER over a downlink to the transmitter when the average observed word error rate avg.sub.-- WER is not within an acceptable word error rate range. The transmitter receives the average observed word error rate avg.sub.-- WER over the downlink and determines a power-code pair (P,c) for the transmitter based on the average observed word error rate avg.sub.-- WER. The power code pair (P,c) defines an operating point of the transmitter, where P of the power-code pair is a selected transmit power level of the transmitter and c of the power-code pair is a selected forward error correcting code used for encoding the data. The receiver can also determine a predicted word error rate WER.sub.Type: GrantFiled: May 8, 1997Date of Patent: June 6, 2000Assignee: Lucent Technologies, Inc.Inventors: Prathima Agrawal, Balakrishnan Narendran, James Paul Sienicki, Shalini Yajnik
-
Patent number: 6052598Abstract: The approximate position of a mobile station in a cell can be predicted by measuring the signal strength between the mobile station and the base station of the cell in which it is located and the base stations of the neighboring cells. After a series of instantaneous signal strength measurements have been collected, the velocity and direction of the mobile unit can be determined. Based on the velocity and direction of the mobile unit, future locations of the mobile unit can be predicted including the projected signal strength between the mobile station and the base stations of the cell in which it is located and neighboring cells. Analyzing the projected signal strength values, the time when the mobile unit will require handover to a neighboring cell can be determined and if desired, resources in a neighboring cell can be allocated in anticipation of the mobile unit being handed over to that cell.Type: GrantFiled: September 30, 1997Date of Patent: April 18, 2000Assignee: AT&T CorpInventors: Ashok N. Rudrapatna, Dharma P. Agrawal, Prathima Agrawal
-
Patent number: 5991629Abstract: A cellular network includes a control station and a network of base stations installed one per cell with which one or more mobile stations can communicate as they roam through a cell. Redundantly deployed spare base stations are introduced along with the primary base station at a central area of each cell. The redundantly deployed spare base stations handle new calls when the associated primary base station is overloaded, participate in retransmission of data lost due to degraded channel conditions and congestion in the network, and assist in handoffs. Primary and spare satellite stations are deployed in regions marked by hills or valleys to augment the communicative capabilities of the primary and spare base stations.Type: GrantFiled: October 14, 1997Date of Patent: November 23, 1999Assignee: AT&T Corp.Inventors: Prathima Agrawal, Ashok N. Rudrapatna
-
Patent number: 5974327Abstract: A method and system adapt scheduling priorities in a wireless communications system to conserve battery power in mobile stations operating within the system. A base station, within the system, receives battery power level information and other setup information from mobile stations operating within the service area of the base station during call setup procedures. Based on the battery power level information and other setup information, the base station assigns frequency channels to the mobile stations so that those mobile stations having battery power levels below a threshold value are assigned frequency channels that have lower interference levels than frequency channels assigned to other mobile stations. The frequency channel assignments are transmitted to the mobile stations.Type: GrantFiled: October 21, 1997Date of Patent: October 26, 1999Assignee: AT&T Corp.Inventors: Prathima Agrawal, Shalinee Kishore, Krishna M. Sivalingam
-
Patent number: 5950134Abstract: A cellular network includes a mobile switching center and a network of cells through which one or more mobile stations can move. Each of the cells is managed by a base station, while a plurality of base stations are controlled by a control processor within the mobile switching center. Spare stations are introduced at strategic locations in the cellular network. As mobile stations move through the network of cells communicating with various base stations and spare stations the mobile switching center receives reports from spare stations relating to the status of various parameters characterizing conditions within the network of cells. The mobile switching center determines the position and velocity of mobile stations moving through the network of cells based on incoming reports. The assignment of a call associated with a mobile station can be changed from a base station to a spare station, and can then be changed from the spare station to another base station if the base station fails or becomes overloaded.Type: GrantFiled: September 8, 1997Date of Patent: September 7, 1999Assignee: AT&T Corp.Inventors: Dharma P. Agrawal, Prathima Agrawal
-
Patent number: 5889816Abstract: A adapter for wireless networking provides for reconfigerable media access control and data packet formats. The flexible adapter comprises a modem interface for controlling an RF modem for transmitting data signals to and receiving data signals from another RF modem; a media access control circuit; and a computer system interface circuit. The computer system interface circuit provides an interface between a host computer system, the modem interface circuit and the media access control circuit.Type: GrantFiled: February 2, 1996Date of Patent: March 30, 1999Assignee: Lucent Technologies, Inc.Inventors: Prathima Agrawal, Mark Robert Cravatts, John Andrew Trotter, Mani Bhushan Srivastava
-
Patent number: 5774461Abstract: A system for delivering packetized data in a network dynamically assigns a unique address to a mobile unit, allocates bandwidth within a wireless link by a token scheme and provides forward error correction for the packet. The system wirelessly transports the packets between a base station and an end point which is responsive to a link cell for linking the base station and the end point. The link cell contains a header and a body. The header in turn contains a forward error correction code, a radioport id and a token. The forward error correction code provides error detection and error correction that relies solely on a one-way communication of data bits from a sender to a receiver. The radioport id is a logical id assigned such that each radio-port in a vicinity has a unique id. The token enables the wireless transportation over a selected channel of the packets between the base station and the end point. The token is utilized to allocate the selected channel from a plurality of channels.Type: GrantFiled: September 27, 1995Date of Patent: June 30, 1998Assignee: Lucent Technologies Inc.Inventors: Eoin Hyden, Mani Bhushan Srivastava, John Andrew Trotter, Prathima Agrawal, Paul Krzyzanowski
-
Patent number: 5768500Abstract: Fueled by higher clock rates and superscalar technologies, growth in processor speed continues to outpace improvement in memory system performance. Reflecting this trend, architects are developing increasingly complex memory hierarchies to mask the speed gap, compiler writers are adding locality enhancing transformations to better utilize complex memory hierarchies, and applications programmers are re-coding their algorithms to exploit memory systems. All of these groups need empirical data on memory behavior to guide their optimizations. This paper describes how to combine simple hardware support and sampling techniques to obtain such data without appreciably perturbing system performance.Type: GrantFiled: November 14, 1996Date of Patent: June 16, 1998Assignee: Lucent Technologies Inc.Inventors: Prathima Agrawal, Aaron Jay Goldberg, John Andrew Trotter
-
Patent number: 5722051Abstract: A dynamic combined power control and forward error correction control (FEC) technique for mobile radio systems which illustratively decreases the power consumed by wireless transmitters and increases the number of simultaneous connections which may be supported thereby. Individual transmitter-receiver pairs may adaptively determine the minimal power and FEC required to satisfy specified quality-of-service (QOS) constraints. Specifically, in accordance with an illustrative embodiment of the present invention, a first portion of a signal is encoded with a first code to generate a first encoded signal portion. Then, the first encoded signal portion is transmitted with a first power level. Next, parameter data is received, wherein the parameter data is representative of one or more characteristics of a received signal portion having been received by the receiver, the received signal portion having been based on the transmitted first encoded signal portion.Type: GrantFiled: February 13, 1996Date of Patent: February 24, 1998Assignee: Lucent Technologies Inc.Inventors: Prathima Agrawal, Balakrishnan Narendran, James Paul Sienicki, Shalini Yajnik
-
Patent number: 5623483Abstract: A network data stream synchronization method and system are disclosed. Operating delay and loss parameters are accepted and a data stream buffer is initialized. The network delay experienced by a data packet is determined and a buffer delay is imposed to provide a fixed end-to-end delay. Packets arriving too late to be played within the fixed end-to-end delay are discarded. Network delay models may be updated and clock drifts may be detected and compensated for using historical buffer data.Type: GrantFiled: May 11, 1995Date of Patent: April 22, 1997Assignee: Lucent Technologies Inc.Inventors: Prathima Agrawal, Balakrishnan Narendran, Narayanan Shivakumar, Cormac J. Sreenan
-
Patent number: 5530912Abstract: A method is disclosed for reducing handover failure probability in cellular networks which includes the steps of determining whether a mobile subscriber is traversing a pre-handover zone defined in each cell of the network, reserving a free channel in an adjacent cell for the mobile subscriber traversing the pre-handover zone, and granting the free channel to the mobile subscriber upon entering a handover region extending across the boundary of the adjacent cells provided that a free channel is available at such a time, and in the alternative, if a free channel is not available at such a time, the handover request is queued until a free channel becomes available.Type: GrantFiled: June 29, 1994Date of Patent: June 25, 1996Assignee: AT&T Corp.Inventors: Prathima Agrawal, Dinesh K. Anvekar, Balakrishnan Narendran
-
Patent number: 5513339Abstract: Test vectors for a circuit containing both logic gates and memory blocks are evaluated by applying candidate test vectors to good and faulty versions of the circuit in a computer simulation. The functions of the gates and interconnections in the circuit are stored in memory and the operation of the good and faulty circuits is simulated concurrently. During the simulation, a memory record is created for storing the state of a circuit element in a faulty circuit if the fault is visible at the element. Such records are removed when no longer needed, which speeds up the simulation. A multiprocessor in a pipeline configuration is disclosed for performing the simulation. A first branch in the pipeline simulates the logic gates in the circuit; a second branch simulates the memory blocks.Type: GrantFiled: December 19, 1994Date of Patent: April 30, 1996Assignee: AT&T Corp.Inventors: Prathima Agrawal, Soumitra Bose
-
Patent number: 5465389Abstract: A method of prioritizing handoff requests in a cellular system is disclosed in which at least one handoff request for assignment of a communication channel is received from at least one mobile unit. A cutoff time for the handoff request is determined. The handoff requests are arranged in a priority queue based on the cutoff time associated with each handoff request. Available communication channels are assigned to the mobile units requesting handoff in the order of the queue.Type: GrantFiled: February 25, 1994Date of Patent: November 7, 1995Assignee: AT&T Corp.Inventors: Prathima Agrawal, Dinesh K. Anvekar, Balakrishnan Narendran
-
Patent number: 5392429Abstract: The present invention relates to the solution of sets of linear equations by microprocessors. In particular, when the process for solving a set of linear equations can be resolved into a set of tasks, each of which can be processed by a processing element in a multiprocessor computer, embodiments of the present invention determine the scheduling of the processing of respective tasks by each processing element. In an exemplary embodiment, the order in which each processing element should process those tasks distributed to it is determined by computing a cost metric indicative of the amount of time required to process the task and a completion time metric, indicative of the amount of time required to process all remaining tasks after that task is completed. Consequently, the tasks distributed to a given processing element are processed in an order based on the completion time metrics computed for the respective tasks.Type: GrantFiled: July 28, 1993Date of Patent: February 21, 1995Assignee: AT&T Corp.Inventors: Prathima Agrawal, Ricardo Telichevesky, John A. Trotter