Patents by Inventor Sai Shankar Nandagopalan

Sai Shankar Nandagopalan 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: 7382694
    Abstract: A plurality of methods, computer program product, and apparatus that use a lower 32 bit field of a 64-bit 802.11 TSF timer, so as to encode the reference time instant without the ambiguity as to whether there the reference time is referring to a future time or a past time. According to an aspect of the present invention, the fact that the low order 32 bits of the TSF timer wraps over in about 71 minutes is exploited to remove any ambiguity in the reference times contained in the Schedule Element frame. One method employs an algorithm base on distance between two reference points to determine whether the timer has wrapped around a time period, and another method uses a delay interval or a timeout to determine whether or not the TSF timer is wrapped or unwrapped. Another method includes determining whether an absolute value of X?O is less than, or greater than or equal to maximum value M/2.
    Type: Grant
    Filed: September 20, 2004
    Date of Patent: June 3, 2008
    Inventors: Javier Del Prado Pavon, Amjad Soomro, Sai Shankar Nandagopalan, Stefan Mangold, Zhun Zhong
  • Patent number: 7317687
    Abstract: A method of transmitting data frames over a data network comprises a step of sending said data frames from a transmitter to a receiver with an Inter Frame Space (IFS) time, which does not include a time (T2) that the transmitter needs to change from a receiver state to a transmitter state, thus substantially increasing the transmission efficiency.
    Type: Grant
    Filed: July 13, 2004
    Date of Patent: January 8, 2008
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Javier Del Prado Pavon, Sai Shankar Nandagopalan
  • Publication number: 20070189244
    Abstract: A system and method is provided for incorporating host-device communication in wireless USB (WUSB). A host (101) either uses a multicast Distributed Reservation Protocol (DRP) frame on behalf of connected devices (102) to reserve wireless channel resources, a unicast DRP frame or Enhanced Distributed Channel Access (EDCA) with a Poll Frame. In the case of a unicast DRP frame the number of unicast frames sent for reservation depends on the number of connected devices (102).
    Type: Application
    Filed: March 4, 2005
    Publication date: August 16, 2007
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS, N.V.
    Inventors: Javier del Prado Pavon, Sai Shankar Nandagopalan, Kiran Challapali, Joerg Habetha
  • Patent number: 7120092
    Abstract: A clock synchronization method and apparatus is disclosed for use in a communication system including a plurality of wireless nodes communicatively coupled via a wireless network, each of the plurality of wireless nodes having a local time base, and one of the plurality of wireless nodes being designated as a master node having a master time base which serves as a master clock against which the local time bases are synchronized. The clock synchronization method includes the steps of periodically transmitting synchronization frames to the plurality of non-master nodes so as to adjust the slave clocks associated with the respective non-master nodes. The synchronization frames are distributed from the master node at near-periodic intervals and includes a cycle time value that corresponds to the end of the previously transmitted synchronization frame. The slave clocks (i.e.
    Type: Grant
    Filed: November 7, 2002
    Date of Patent: October 10, 2006
    Assignee: Koninklijke Philips Electronics N. V.
    Inventors: Javier del Prado Pavon, Sai Shankar Nandagopalan, Sunghyun Choi, Takashi Sato, Jeff Bennet
  • Publication number: 20060194601
    Abstract: Admission control for parameterized traffic among wireless stations and an access point takes into account time varying channel capacity as well as loss characteristics of the wireless channel in guaranteeing specified quality-of-service (QoS). In addition, transmission burstiness, which is a difference between a minimum transmission rate specified by the station and a current transmission rate, is used to increase the bandwidth guaranteed at admission. Both size overhead, as from packet headers, and time overhead, as from polling, is taken into account in an admission process that converts a guaranteed transmission rate into air time units. Efficient admission control is accomplished using a minimal subset of the standard parameters specified by the wireless station.
    Type: Application
    Filed: July 20, 2004
    Publication date: August 31, 2006
    Inventor: Sai Shankar Nandagopalan
  • Publication number: 20040264495
    Abstract: A method of contention resolution in a medium access control system, with particular application to an upstream link in a HFC network is disclosed. In the medium, data is transmitted in frames, each comprising a plurality of slots. At least two (and typically more) of these slots in each frame are contention slots. At least one contention slot in each frame is reserved for new arrivals to a contention tree that wish to access the channel capacity using contention resolution and at least one further contention slot is reserved for resolving contention if there is collision in the arrival slot. Arrivals that collide in the arrival slot contend for entry into the tree in the contention slots.
    Type: Application
    Filed: May 12, 2004
    Publication date: December 30, 2004
    Inventor: Sai Shankar Nandagopalan
  • Publication number: 20030172179
    Abstract: A clock synchronization method and apparatus is disclosed for use in a communication system including a plurality of wireless nodes communicatively coupled via a wireless network, each of the plurality of wireless nodes having a local time base, and one of the plurality of wireless nodes being designated as a master node having a master time base which serves as a master clock against which the local time bases are synchronized. The clock synchronization method includes the steps of periodically transmitting synchronization frames to the plurality of non-master nodes so as to adjust the slave clocks associated with the respective non-master nodes. The synchronization frames are distributed from the master node at near-periodic intervals and includes a cycle time value that corresponds to the end of the previously transmitted synchronization frame. The slave clocks (i.e.
    Type: Application
    Filed: November 7, 2002
    Publication date: September 11, 2003
    Inventors: Javier del Prado Pavon, Sai Shankar Nandagopalan, Sunghyun Choi, Takashi Sato, Jeff Bennet