Patents by Inventor Lik Chuen Alec Woo

Lik Chuen Alec Woo 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: 9848422
    Abstract: In one embodiment, a rendezvous request message is generated (e.g., by a sender) that specifies a channel C and a rendezvous time T for which a distributed message is to be transmitted in a frequency-hopping computer network. The rendezvous request message is then transmitted on one or more channels used in the computer network based on reaching a plurality of intended recipients of the distributed message with the rendezvous request message prior to rendezvous time T. Accordingly, the distributed message is then transmitted on channel C at rendezvous time T. In another embodiment, a device receives a rendezvous request message, and in response to determining to honor the rendezvous request message, listens for the distributed message on channel C at rendezvous time T.
    Type: Grant
    Filed: September 10, 2014
    Date of Patent: December 19, 2017
    Assignee: Cisco Technology, Inc.
    Inventors: Lik Chuen Alec Woo, Jonathan W. Hui, Wei Hong
  • Patent number: 9648543
    Abstract: A system and method adds and manages entries on a list of entries of routing information to allow the top entry to be used for routing to a destination corresponding to the list. Costs of a wireless link may be a function of the success rate experienced on that wireless link.
    Type: Grant
    Filed: September 18, 2014
    Date of Patent: May 9, 2017
    Assignee: Cisco Technology, Inc.
    Inventors: Jonathan W. Hui, Lik Chuen Alec Woo, David E. Culler
  • Patent number: 9515874
    Abstract: In one embodiment, each of a plurality of devices in a computer network is configured to i) transmit a unicasted dynamic host configuration protocol (DHCP) solicit message to a neighbor device having a route to a border router as an assumed DHCP relay without regard to location of a DHCP server, and ii) operate as a DHCP relay to receive unicasted DHCP solicit messages and relay the solicit message to the border router of the network without regard to location of the DHCP server, and to relay a DHCP reply to a corresponding requestor device.
    Type: Grant
    Filed: July 16, 2014
    Date of Patent: December 6, 2016
    Assignee: Cisco Technology, Inc.
    Inventors: Jonathan W. Hui, Lik Chuen Alec Woo, Wei Hong
  • Patent number: 9450642
    Abstract: In one embodiment, a communication device samples a particular frequency hopping sequence during only a particular specified sub-timeslot of a timeslot. If a transmission energy is not detected during the specified sub-timeslot, the device turns off its receiver for a remainder of the timeslot. Otherwise, it continues to sample the particular frequency hopping sequence for at least one or more additional sub-timeslots of the remainder of the timeslot. In another embodiment, a communication device determines whether a neighboring communication device is operating in a first mode or a second mode. If in the second mode, it transmits a transmission to the neighboring communication device starting at any sub-timeslot of the plurality of sub-timeslots. If in the first mode, it transmits the transmission to the neighboring communication device while ensuring that the transmission is actively energized during a particular specified sub-timeslot.
    Type: Grant
    Filed: July 12, 2011
    Date of Patent: September 20, 2016
    Assignee: Cisco Technology, Inc.
    Inventors: Jonathan W. Hui, Wei Hong, Lik Chuen Alec Woo
  • Patent number: 9281865
    Abstract: In one embodiment, a device in a frequency hopping communication network transmits responsive beacon messages based on adaptive types of responsive beacon message transmission based on a number of received beacon requests within a given time period: the number below a threshold results in synchronized unicast messages; the number above the threshold results in unsynchronized broadcast messages. In another embodiment, the device suppresses unsolicited beacon message transmission based on a density-aware redundancy count of other unsolicited beacon message transmissions from neighboring devices. In another embodiment, the device may transmit unsolicited beacon messages according to an adaptive interval based on stability of the network.
    Type: Grant
    Filed: October 13, 2011
    Date of Patent: March 8, 2016
    Assignee: Cisco Technology, Inc.
    Inventors: Jonathan W. Hui, Lik Chuen Alec Woo, Wei Hong
  • Patent number: 9020008
    Abstract: In one embodiment, each device in a frequency hopping communication network independently determines its own local unicast listening schedule, and discovers a neighbor unicast listening schedule for each of its neighbors. The devices also synchronize to a common broadcast schedule for the network that simultaneously overlays a configured portion of all unicast listening schedules in the network. Accordingly, the device operate in a receive mode according to their local unicast listening schedule and the common broadcast schedule during the overlaid configured portion, and in a transmit mode according to each neighbor unicast listening schedule and the common broadcast schedule during the overlaid configured portion depending upon a destination of transmitted traffic.
    Type: Grant
    Filed: July 12, 2011
    Date of Patent: April 28, 2015
    Assignee: Cisco Technology, Inc.
    Inventors: Jonathan W. Hui, Wei Hong, Lik Chuen Alec Woo
  • Patent number: 9001676
    Abstract: In one embodiment, a device in a frequency hopping communication network operate in a first mode according to a common broadcast schedule for the network that simultaneously overlays a first configured portion of all independently determined unicast listening schedules in the network. In response to determining a power outage condition, the device switches to operation in a power outage mode where the common broadcast schedule for the network in the power outage mode simultaneously overlays a second configured portion of all independently determined unicast listening schedules in the network, the second configured portion greater than the first configured portion. In one embodiment, the device broadcasts one or more power outage notifications (PONs) in response to determining the power outage condition as a reduction of a main power supply at the device. In another embodiment, the device receives a PON while powered as the power outage condition.
    Type: Grant
    Filed: July 28, 2011
    Date of Patent: April 7, 2015
    Assignee: Cisco Technology, Inc.
    Inventors: Jonathan W. Hui, Wei Hong, Lik Chuen Alec Woo
  • Patent number: 8964762
    Abstract: In one embodiment, a battery-operated communication device “quick-samples” a frequency hopping sequence at a periodic rate corresponding to a substantially low duty cycle, and is discovered by (e.g., attached to) a main-powered communication device. During a scheduled sample, the main-powered communication device transmits a control packet to be received by the battery-operated communication device, the control packet containing timing information and transmitted to account for worst-case clock drift error between the two devices. The battery-operated communication device responds to the control packet with a link-layer acknowledgment containing timing information from the battery-operated communication device. Accordingly, the two devices may re-synchronize their timing based on the timing information in the control packet and acknowledgment, respectively.
    Type: Grant
    Filed: November 20, 2013
    Date of Patent: February 24, 2015
    Assignee: Cisco Technology, Inc.
    Inventors: Jonathan W. Hui, Lik Chuen Alec Woo, Wei Hong
  • Publication number: 20150003396
    Abstract: A system and method adds and manages entries on a list of entries of routing information to allow the top entry to be used for routing to a destination corresponding to the list. Costs of a wireless link may be a function of the success rate experienced on that wireless link.
    Type: Application
    Filed: September 18, 2014
    Publication date: January 1, 2015
    Inventors: Jonathan W. Hui, Lik Chuen Alec Woo, David E. Culler
  • Publication number: 20150003428
    Abstract: In one embodiment, a rendezvous request message is generated (e.g., by a sender) that specifies a channel C and a rendezvous time T for which a distributed message is to be transmitted in a frequency-hopping computer network. The rendezvous request message is then transmitted on one or more channels used in the computer network based on reaching a plurality of intended recipients of the distributed message with the rendezvous request message prior to rendezvous time T. Accordingly, the distributed message is then transmitted on channel C at rendezvous time T. In another embodiment, a device receives a rendezvous request message, and in response to determining to honor the rendezvous request message, listens for the distributed message on channel C at rendezvous time T.
    Type: Application
    Filed: September 10, 2014
    Publication date: January 1, 2015
    Inventors: Lik Chuen Alec Woo, Jonathan W. Hui, Wei Hong
  • Publication number: 20140330947
    Abstract: In one embodiment, each of a plurality of devices in a computer network is configured to i) transmit a unicasted dynamic host configuration protocol (DHCP) solicit message to a neighbor device having a route to a border router as an assumed DHCP relay without regard to location of a DHCP server, and ii) operate as a DHCP relay to receive unicasted DHCP solicit messages and relay the solicit message to the border router of the network without regard to location of the DHCP server, and to relay a DHCP reply to a corresponding requestor device.
    Type: Application
    Filed: July 16, 2014
    Publication date: November 6, 2014
    Inventors: Jonathan W. Hui, Lik Chuen Alec Woo, Wei Hong
  • Patent number: 8879604
    Abstract: In one embodiment, a rendezvous request message is generated (e.g., by a sender) that specifies a channel C and a rendezvous time T for which a distributed message is to be transmitted in a frequency-hopping computer network. The rendezvous request message is then transmitted on one or more channels used in the computer network based on reaching a plurality of intended recipients of the distributed message with the rendezvous request message prior to rendezvous time T. Accordingly, the distributed message is then transmitted on channel C at rendezvous time T. In another embodiment, a device receives a rendezvous request message, and in response to determining to honor the rendezvous request message, listens for the distributed message on channel C at rendezvous time T.
    Type: Grant
    Filed: July 6, 2011
    Date of Patent: November 4, 2014
    Assignee: Cisco Technology, Inc.
    Inventors: Lik Chuen Alec Woo, Jonathan W. Hui, Wei Hong
  • Patent number: 8819191
    Abstract: In one embodiment, each of a plurality of devices in a computer network is configured to i) transmit a unicasted dynamic host configuration protocol (DHCP) solicit message to a neighbor device having a route to a border router as an assumed DHCP relay without regard to location of a DHCP server, and ii) operate as a DHCP relay to receive unicasted DHCP solicit messages and relay the solicit message to the border router of the network without regard to location of the DHCP server, and to relay a DHCP reply to a corresponding requestor device.
    Type: Grant
    Filed: July 12, 2011
    Date of Patent: August 26, 2014
    Assignee: Cisco Technology, Inc.
    Inventors: Jonathan W. Hui, Lik Chuen Alec Woo, Wei Hong
  • Patent number: 8699368
    Abstract: In one embodiment, a transmitter in a communication network receives an indication of active transmission times of a receiver to which the transmitter attempts to reach with first transmissions, the active transmission times indicating respective times of second transmissions initiated by the receiver. Based on determining when the first transmissions occur, the transmitter may then compute a link reliability metric for a link from the transmitter to the receiver by excluding one or more of the first transmissions from the indicated active transmission times of the second transmissions. In one embodiment, the active transmission times are in the past and the reliability metric excludes any first transmissions in the past during those times, while in another embodiment the active transmission times are scheduled in the future and the reliability metric does not include any first transmissions since the first transmissions may be scheduled to avoid the active transmission times.
    Type: Grant
    Filed: July 26, 2011
    Date of Patent: April 15, 2014
    Assignee: Cisco Technology, Inc.
    Inventors: Jonathan W. Hui, Lik Chuen Alec Woo, Wei Hong
  • Publication number: 20140064172
    Abstract: In one embodiment, a battery-operated communication device “quick-samples” a frequency hopping sequence at a periodic rate corresponding to a substantially low duty cycle, and is discovered by (e.g., attached to) a main-powered communication device. During a scheduled sample, the main-powered communication device transmits a control packet to be received by the battery-operated communication device, the control packet containing timing information and transmitted to account for worst-case clock drift error between the two devices. The battery-operated communication device responds to the control packet with a link-layer acknowledgment containing timing information from the battery-operated communication device. Accordingly, the two devices may re-synchronize their timing based on the timing information in the control packet and acknowledgment, respectively.
    Type: Application
    Filed: November 20, 2013
    Publication date: March 6, 2014
    Applicant: CISCO TECHNOLOGY, INC.
    Inventors: Jonathan W. Hui, Lik Chuen Alec Woo, Wei Hong
  • Patent number: 8619789
    Abstract: In one embodiment, a battery-operated communication device “quick-samples” a frequency hopping sequence at a periodic rate corresponding to a substantially low duty cycle, and is discovered by (e.g., attached to) a main-powered communication device. During a scheduled sample, the main-powered communication device transmits a control packet to be received by the battery-operated communication device, the control packet containing timing information and transmitted to account for worst-case clock drift error between the two devices. The battery-operated communication device responds to the control packet with a link-layer acknowledgment containing timing information from the battery-operated communication device. Accordingly, the two devices may re-synchronize their timing based on the timing information in the control packet and acknowledgment, respectively.
    Type: Grant
    Filed: July 12, 2011
    Date of Patent: December 31, 2013
    Assignee: Cisco Technology, Inc.
    Inventors: Jonathan W. Hui, Lik Chuen Alec Woo, Wei Hong
  • Publication number: 20130094536
    Abstract: In one embodiment, a device in a frequency hopping communication network transmits responsive beacon messages based on adaptive types of responsive beacon message transmission based on a number of received beacon requests within a given time period: the number below a threshold results in synchronized unicast messages; the number above the threshold results in unsynchronized broadcast messages. In another embodiment, the device suppresses unsolicited beacon message transmission based on a density-aware redundancy count of other unsolicited beacon message transmissions from neighboring devices. In another embodiment, the device may transmit unsolicited beacon messages according to an adaptive interval based on stability of the network.
    Type: Application
    Filed: October 13, 2011
    Publication date: April 18, 2013
    Applicant: Cisco Technology, Inc.
    Inventors: Jonathan W. Hui, Lik Chuen Alec Woo, Wei Hong
  • Publication number: 20130028103
    Abstract: In one embodiment, a transmitter in a communication network receives an indication of active transmission times of a receiver to which the transmitter attempts to reach with first transmissions, the active transmission times indicating respective times of second transmissions initiated by the receiver. Based on determining when the first transmissions occur, the transmitter may then compute a link reliability metric for a link from the transmitter to the receiver by excluding one or more of the first transmissions from the indicated active transmission times of the second transmissions. In one embodiment, the active transmission times are in the past and the reliability metric excludes any first transmissions in the past during those times, while in another embodiment the active transmission times are scheduled in the future and the reliability metric does not include any first transmissions since the first transmissions may be scheduled to avoid the active transmission times.
    Type: Application
    Filed: July 26, 2011
    Publication date: January 31, 2013
    Applicant: Cisco Technology, Inc.
    Inventors: Jonathan W. Hui, Lik Chuen Alec Woo, Wei Hong
  • Publication number: 20130028295
    Abstract: In one embodiment, a device in a frequency hopping communication network operate in a first mode according to a common broadcast schedule for the network that simultaneously overlays a first configured portion of all independently determined unicast listening schedules in the network. In response to determining a power outage condition, the device switches to operation in a power outage mode where the common broadcast schedule for the network in the power outage mode simultaneously overlays a second configured portion of all independently determined unicast listening schedules in the network, the second configured portion greater than the first configured portion. In one embodiment, the device broadcasts one or more power outage notifications (PONs) in response to determining the power outage condition as a reduction of a main power supply at the device. In another embodiment, the device receives a PON while powered as the power outage condition.
    Type: Application
    Filed: July 28, 2011
    Publication date: January 31, 2013
    Applicant: CISCO TECHNOLOGY, INC.
    Inventors: Jonathan W. Hui, Wei Hong, Lik Chuen Alec Woo
  • Publication number: 20130016757
    Abstract: In one embodiment, a battery-operated communication device “quick-samples” a frequency hopping sequence at a periodic rate corresponding to a substantially low duty cycle, and is discovered by (e.g., attached to) a main-powered communication device. During a scheduled sample, the main-powered communication device transmits a control packet to be received by the battery-operated communication device, the control packet containing timing information and transmitted to account for worst-case clock drift error between the two devices. The battery-operated communication device responds to the control packet with a link-layer acknowledgment containing timing information from the battery-operated communication device. Accordingly, the two devices may re-synchronize their timing based on the timing information in the control packet and acknowledgment, respectively.
    Type: Application
    Filed: July 12, 2011
    Publication date: January 17, 2013
    Applicant: CISCO TECHNOLOGY, INC.
    Inventors: Jonathan W. Hui, Lik Chuen Alec Woo, Wei Hong