Patents by Inventor Paparao Palacharla

Paparao Palacharla 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: 9197350
    Abstract: A method for routing and wavelength assignment for optical network resources required for a plurality of virtual network requests includes receiving the plurality of virtual network requests. The method further includes determining a number of virtual links for each virtual network request. The method includes sorting the plurality of virtual network requests based on the number of virtual links, and selecting a virtual network request from the plurality of virtual network requests and setting a number of allowable spans. Additionally, the method includes determining whether a valid virtual node mapping exists for the virtual network request on any of a plurality of wavelengths based on the allowable spans, and based on determining that no valid virtual node mapping exists on any of the plurality of wavelengths, incrementing the number of allowable spans.
    Type: Grant
    Filed: September 25, 2013
    Date of Patent: November 24, 2015
    Assignee: Fujitsu Limited
    Inventors: Qiong Zhang, Weisheng Xie, Qingya She, Xi Wang, Paparao Palacharla, Motoyoshi Sekiya
  • Patent number: 9197542
    Abstract: The present disclosure may include a method of reconfiguring a network. The method includes collecting a plurality of network demands, each of the plurality of network demands having a possible resource release by rerouting the network demand from its current path to a new path. The method further includes selecting a subset of the plurality of network demands that, if rerouted, has the highest resource release without resource contention. The method additionally includes rerouting the subset of the plurality of network demands, and, in response to rerouting the subset of the plurality of network demands, releasing resources no longer used by rerouted demands. The present disclosure may further include associated systems and apparatuses.
    Type: Grant
    Filed: January 31, 2013
    Date of Patent: November 24, 2015
    Assignee: Fujitsu Limited
    Inventors: Qiong Zhang, Paparao Palacharla, Chengyi Gao, Xi Wang, Motoyoshi Sekiya
  • Publication number: 20150333825
    Abstract: Methods and systems are provided for flexible placement of spectral inverters in an optical network. The method includes identifying a first transmission path coupling a transmitter and a receiver. The first transmission path includes a first node for assignment of a first spectral inverter. The method further includes estimating a first optical signal-to-noise ratio (OSNR) penalty of nonlinear phase noise (NLPN) on the first transmission path with the first spectral inverter assigned to the first node, and based on the first estimated OSNR penalty of NLPN being less than an NLPN penalty threshold, assigning the first spectral inverter to the first node.
    Type: Application
    Filed: May 14, 2014
    Publication date: November 19, 2015
    Inventors: Inwoong Kim, Olga Vassilieva, Paparao Palacharla, Motoyoshi Sekiya
  • Publication number: 20150295673
    Abstract: Optical transceiver sharing methods may be based on different ROADM node architectures for shared restoration in flexible grid optical networks. A ROADM node architecture with a pool of transceivers may improve transceiver utilization for backup optical paths, compared to a conventional ROADM node architecture. Sharing of transceivers in the pool for working and backup optical paths may further improve transceiver utilization. The methods disclosed herein may be used for multiple bit rates and different modulation formats.
    Type: Application
    Filed: February 12, 2015
    Publication date: October 15, 2015
    Inventors: Qiong Zhang, Xi Wang, Paparao Palacharla, Motoyoshi Sekiya
  • Publication number: 20150295761
    Abstract: Object-oriented network virtualization may involve creating and operating virtual network objects (VNO) using a software-programmed networking operating system (SPN OS). A VNO may be a complete representation of a virtual network service provided under the SPN OS. A VNO may have a unique identity and properties, along with an internal set of methods for executing functionality encapsulated by the VNO. A VNO may exhibit persistence and autonomous control to enable improved virtual network services.
    Type: Application
    Filed: December 18, 2014
    Publication date: October 15, 2015
    Inventors: Xi Wang, Motoyoshi Sekiya, Paparao Palacharla, Qiong Zhang, Inwoong Kim
  • Patent number: 9154858
    Abstract: An optical network analysis tool includes a computer-readable storage medium having computer-readable instructions stored thereon. The computer-readable instructions are executable by a computing device to perform operations. The operations include generating a simulated network that models an optical network. The simulated network includes regenerator candidate sites. The operations may also include conducting an analysis of the optical network. The analysis includes introducing a multiple signals transmitted between source/destination pairs and recording a number of times each of the regenerator candidate sites are selected as a regenerator site while applying each of a set of data traffic conditions in the simulated network. The operations may also include statistically analyzing the number of times each of the regenerator candidate sites is selected to generate statistically analyzed information and presenting the statistically analyzed information.
    Type: Grant
    Filed: August 14, 2012
    Date of Patent: October 6, 2015
    Assignee: FUJITSU LIMITED
    Inventors: Xi Wang, Qiong Zhang, Paparao Palacharla, Motoyoshi Sekiya
  • Patent number: 9112609
    Abstract: Methods and systems for mitigating effects of polarization dependent loss (PDL) in an optical network transmitting a multi-carrier optical signal comprising a plurality of subcarriers may involve assigning and modifying a state of polarization to each subcarrier prior to transmission. An assigned state of polarization for each subcarrier may be modified for the subcarrier in the digital domain and/or the optical domain. Various specific assignment methods may be used, including individual subcarrier assignment, subcarrier set assignment, arbitrary subcarrier group assignment, random assignment, and/or combinations thereof. The assigned states of polarization may be selected based on a resulting minimum PDL-induced peak-to-peak power variation over a sum of the subcarriers for all orientations of a principal axis of PDL.
    Type: Grant
    Filed: June 10, 2013
    Date of Patent: August 18, 2015
    Assignee: Fujitsu Limited
    Inventors: Inwoong Kim, Olga Vassilieva, Paparao Palacharla, Motoyoshi Sekiya
  • Patent number: 9083485
    Abstract: According to an aspect of an embodiment, a method of spectrum defragmentation in an optical network may include assigning an optical signal within an optical network to a first frequency slot that spans a first portion of an optical spectrum of the optical network. The method may also include constructing a frequency slot dependency map based on the assignation of the optical signal to the frequency slot. The method may also include reassigning, as a result of an optical signal departure event, the optical signal to a second frequency slot based on the frequency slot dependency map. The second frequency slot may span a second portion of the optical spectrum of the optical network.
    Type: Grant
    Filed: April 12, 2012
    Date of Patent: July 14, 2015
    Assignee: FUJITSU LIMITED
    Inventors: Xi Wang, Inwoong Kim, Paparao Palacharla, Motoyoshi Sekiya
  • Patent number: 9014559
    Abstract: In accordance with some embodiments of the present disclosure a method for shared mesh protection in an optical transport network comprises provisioning a route for each of a plurality of working demands through the optical transport network. The method further comprises provisioning a route for backup demands corresponding to each of the plurality of working demands. The method additionally comprises packing into a single optical data unit a first backup demand corresponding to a first of the plurality of working demands and a second backup demand corresponding to a second of the plurality of working demands, wherein the first and second of the plurality of working demands share at least one common link in the optical transport network. The method also comprises unpacking the first and second backup demands from the optical data unit.
    Type: Grant
    Filed: May 26, 2011
    Date of Patent: April 21, 2015
    Assignee: Fujitsu Limited
    Inventors: Qiong Zhang, Paparao Palacharla, Motoyoshi Sekiya
  • Publication number: 20150104172
    Abstract: Flexible VON provisioning may include calculating a candidate mapping pattern to satisfy a virtual optical network (VON) demand based on virtual-to-physical node mapping choices. A distance-adaptive routing and spectral slot assignment evaluation of the candidate mapping pattern may be performed. When the VON demand is satisfied by the candidate mapping pattern, the candidate mapping pattern may be added to a valid mapping patterns list. A final mapping pattern may be selected from the valid mapping patterns list, the final mapping pattern having one of a lowest slot layer and a smallest overall slot usage on the valid mapping patterns list. Then, network resources may be reserved based on the final mapping pattern selected to service the VON demand.
    Type: Application
    Filed: June 25, 2014
    Publication date: April 16, 2015
    Inventors: Xi Wang, Qiong Zhang, Inwoong Kim, Paparao Palacharla, Motoyoshi Sekiya
  • Patent number: 8989571
    Abstract: According to an aspect of an embodiment, a method of modulating supervisory data onto an optical signal includes increasing a first power level of a first polarization component of an optical signal based on supervisory data. The method further includes decreasing a second power level of a second polarization component of the optical signal based on the supervisory data. The decrease in the second power level is substantially the same as the increase in the first power level such that a total power of the optical signal is substantially constant.
    Type: Grant
    Filed: September 14, 2012
    Date of Patent: March 24, 2015
    Assignee: Fujitsu Limited
    Inventors: Inwoong Kim, Olga Vassilieva, Paparao Palacharla, Motoyoshi Sekiya
  • Patent number: 8989581
    Abstract: An optical network for reassigning a carrier wavelength of an optical signal may include first and second optical nodes. The first optical node may be configured to transmit an optical signal along an optical path. The first optical node may also be configured to tune a carrier wavelength of the optical signal from a first wavelength to a second wavelength, according to a continuous function, to reassign the carrier wavelength of the optical signal. The second optical node may be configured to receive the optical signal and may include a feedback loop configured to adjust a wavelength of a reference optical signal to approximate the carrier wavelength of the optical signal.
    Type: Grant
    Filed: March 22, 2012
    Date of Patent: March 24, 2015
    Assignee: Fujitsu Limited
    Inventors: Inwoong Kim, Paparao Palacharla, Xi Wang, Motoyoshi Sekiya
  • Patent number: 8983290
    Abstract: Systems and method for monitoring an optical power of a dual-polarization signal are disclosed. The systems and methods may include measuring a first parameter set associated with a supervisory signal, the supervisory signal being communicated in-band with the dual-polarization signal; calculating a second parameter set from the first parameter set; calculating an intensity value from the second parameter set, the intensity value associated with one of the polarization states of the dual-polarization signal; and estimating a signal power associated with the supervisory signal from the intensity value.
    Type: Grant
    Filed: June 24, 2013
    Date of Patent: March 17, 2015
    Assignee: Fujitsu Limited
    Inventors: Inwoong Kim, Olga Vassilieva, Paparao Palacharla, Motoyoshi Sekiya, Jeng-Yuan Yang
  • Patent number: 8965198
    Abstract: A method for shared mesh restoration includes configuring a switch to allow sharing of a plurality of backup line cards across a plurality of node degrees associated with a reconfigurable optical add/drop multiplexer (ROADM). The switch is communicatively coupled to the ROADM. The method further includes configuring a number of backup line cards coupled to the switch. The number of backup line cards is based on determining a number of active backup lightpaths for each of a plurality of network failures associated with each of the plurality of node degrees of the ROADM, identifying which node degree and failure has the largest number of active backup lightpaths for all of the plurality of node degrees of the ROADM and for each of the plurality of network failures, and determining the number of backup line cards to configure based on the identified largest number of active backup lightpaths.
    Type: Grant
    Filed: October 23, 2012
    Date of Patent: February 24, 2015
    Assignee: Fujitsu Limited
    Inventors: Qiong Zhang, Paparao Palacharla, Xi Wang, Motoyoshi Sekiya
  • Patent number: 8942114
    Abstract: A system and method are provided for monitoring traffic in a network comprising a plurality of links, wherein each of the plurality of links comprises a plurality of neighboring pairs of slots. The system and method may include identifying a first usage status and a second usage status, calculating a utilization entropy value based at least on the difference between the first and second usage status, iteratively calculating a set of utilization entropy values for a portion of the network, and calculating an overall utilization entropy value for the portion of the network under analysis based at least on a statistical analysis of the set of utilization entropy values.
    Type: Grant
    Filed: June 21, 2011
    Date of Patent: January 27, 2015
    Assignee: Fujitsu Limited
    Inventors: Xi Wang, Inwoong Kim, Qiong Zhang, Paparao Palacharla, Motoyoshi Sekiya
  • Publication number: 20140376908
    Abstract: Systems and method for monitoring an optical power of a dual-polarization signal are disclosed. The systems and methods may include measuring a first parameter set associated with a supervisory signal, the supervisory signal being communicated in-band with the dual-polarization signal; calculating a second parameter set from the first parameter set; calculating an intensity value from the second parameter set, the intensity value associated with one of the polarization states of the dual-polarization signal; and estimating a signal power associated with the supervisory signal from the intensity value.
    Type: Application
    Filed: June 24, 2013
    Publication date: December 25, 2014
    Inventors: Inwoong Kim, Olga Vassilieva, Paparao Palacharla, Motoyoshi Sekiya, Jeng-Yuan Yang
  • Publication number: 20140363164
    Abstract: Methods and systems for mitigating effects of polarization dependent loss (PDL) in an optical network transmitting a multi-carrier optical signal comprising a plurality of subcarriers may involve assigning and modifying a state of polarization to each subcarrier prior to transmission. An assigned state of polarization for each subcarrier may be modified for the subcarrier in the digital domain and/or the optical domain. Various specific assignment methods may be used, including individual subcarrier assignment, subcarrier set assignment, arbitrary subcarrier group assignment, random assignment, and/or combinations thereof. The assigned states of polarization may be selected based on a resulting minimum PDL-induced peak-to-peak power variation over a sum of the subcarriers for all orientations of a principal axis of PDL.
    Type: Application
    Filed: June 10, 2013
    Publication date: December 11, 2014
    Inventors: Inwoong Kim, Olga Vassilieva, Paparao Palacharla, Motoyoshi Sekiya
  • Patent number: 8909049
    Abstract: In accordance with embodiments of the present disclosure, a method may include determining individual spectrum requirements for each of a plurality of signals to be communicated in an optical network, wherein a first signal of the plurality of signals has a first spectrum requirement and a second signal of the plurality of signals has a second spectrum requirement. The method may also include calculating a minimum spectrum granularity based on the individual spectrum requirements. The method may further include assigning each particular signal a channel spectrum equal to an integer multiple of the minimum spectrum granularity.
    Type: Grant
    Filed: July 1, 2011
    Date of Patent: December 9, 2014
    Assignee: Fujitsu Limited
    Inventors: Xi Wang, Qiong Zhang, Inwoong Kim, Paparao Palacharla, Motoyoshi Sekiya
  • Patent number: 8891956
    Abstract: In accordance with embodiments of the present disclosure, a method may include for each particular working demand in a communication network, calculating a dedicated backup path for a working path of the particular working demand such that each particular backup path does not include links present in the working path. The method may also include, for each particular working demand: (i) assigning to the backup path a wavelength associated with the particular working demand; and (ii) assign to the backup path a transponder at each of the source and destination of the backup path associated with the wavelength; such that the backup path for at least one particular working demand is assigned a transponder that is also assigned to the backup path for at least one other particular working demand.
    Type: Grant
    Filed: June 2, 2011
    Date of Patent: November 18, 2014
    Assignee: Fujitsu Limited
    Inventors: Xi Wang, Paparao Palacharla
  • Publication number: 20140317257
    Abstract: A method employing resource orchestration algorithms may find a fewest number of working data centers (DCs) to guarantee K-connect survivability using an overlay network representing a physical optical network. The overlay network may not include certain topological features of the physical optical network. A risk-based algorithm may result in fewer working DCs for K-connect survivability. A delay-based algorithm may be more suitable for delay-sensitive cloud applications.
    Type: Application
    Filed: December 10, 2013
    Publication date: October 23, 2014
    Applicant: Fujitsu Limited
    Inventors: Qiong Zhang, Qingya She, Xi Wang, Paparao Palacharla, Motoyoshi Sekiya