# US 9,955,456 B2 · Network discovery in low-power and lossy networks > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,955,456 B2 - Document ID: US9955456B2 - Status: Granted - Kind: B2 - Application number: 14/551,252 - Filed: 2014-11-24 - Published: 2016-05-26 - Granted: 2018-04-24 - Earliest claimed: 2014-11-24 - Assignees: Cisco Technology, Inc. - Applicants: Cisco Technology, Inc. - Inventors: Jonathan Hui; Wei Hong - Web page: https://patentgrep.com/patent/US9955456B2 ## CPC - H04W 72/30: Resource management for broadcast services - H04B 1/7156: Arrangements for sequence synchronisation - H04W 4/06: Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services - H04W 68/005: {Transmission of information for alerting of incoming communication} - H04W 76/40: for selective distribution or broadcast - H04B 2001/71563: {Acquisition} - H04B 2201/71338: Asynchronous systems - H04W 72/12: Wireless traffic scheduling - Y02D 30/70: in wireless communication networks - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04B: TRANSMISSION - Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE ## Abstract In one embodiment, a device in a network determines a first channel hopping schedule for the device to receive unicast communications from one or more neighbors of the device. The first channel hopping schedule differs from channel hopping schedules used by the one or more neighbors to receive unicast communications. The device determines a second channel hopping schedule for the device that includes a common channel that is common to the device and the one or more neighbors at any given point in time, wherein the second channel hopping schedule is self-generated by each of the device and the one or more neighbors. The device switches from the first channel hopping schedule to the second channel hopping schedule, in response to a network event. The device causes a particular neighbor to join the network using the second channel hopping schedule. ## Claims ### Claim 1 A method, comprising: determining, by a device in a network, a first channel hopping schedule for the device to receive unicast communications from one or more neighbors of the device, wherein the first channel hopping schedule differs from channel hopping schedules used by the one or more neighbors to receive unicast communications; determining, by the device, a common second channel hopping schedule for the device for network discovery that includes channels that are common to the device and the one or more neighbors at every given point in time, wherein the second channel hopping schedule is based on parameters that are preconfigured across the device and the one or more neighbors prior to deployment, and wherein the same common second channel hopping schedule is self-generated by each of the device and the one or more neighbors based on the preconfigured parameters and without aid of a coordinating device; switching, by the device, from the first channel hopping schedule to the second channel hopping schedule, in response to a network event; and causing, by the device, a particular neighbor to join the network using the second channel hopping schedule. ### Claim 2 (depends on 1) The method as in claim 1, wherein the network event is a power outage event in the network. ### Claim 3 (depends on 1) The method as in claim 1, wherein causing the particular neighbor to join the network using the second channel hopping schedule comprises: sending, by the device, a beacon to the particular neighbor using one of the common channels. ### Claim 4 (depends on 1) The method as in claim 1, further comprising: receiving, at the device, a power restoration notification from the particular neighbor using one of the common channels. ### Claim 5 (depends on 1) The method as in claim 1, further comprising: notifying, by the device, one or more of the neighbors of the device as to when the device is going to switch from the first channel hopping schedule to the second channel hopping schedule. ### Claim 6 (depends on 1) The method as in claim 1, wherein the network event comprises receiving an instruction to switch channel hopping schedules. ### Claim 7 (depends on 1) The method as in claim 1, wherein the second channel hopping schedule is determined by the device based in part on a real time clock of the device. ### Claim 8 (depends on 7) The method as in claim 7, wherein the second channel hopping schedule is determined by the device based further in part on a deployment identifier. ### Claim 9 (depends on 1) The method as in claim 1 wherein channels in the first channel hopping schedule are hopped more frequently than the common channels are hopped in the second channel hopping schedule. ### Claim 10 (depends on 1) The method as in claim 1, further comprising: switching, by the device, back to the first channel hopping schedule after the particular neighbor joins the network. ### Claim 11 (depends on 1) The method as in claim 1, further comprising: receiving, at the device, a beacon request from a portable device via a channel of the first channel hopping schedule and on behalf of one of the one or more neighbors; and providing, by the device, a beacon using the first channel hopping schedule, in response to receiving the beacon request from the portable device. ### Claim 12 An apparatus, comprising: one or more network interfaces to communicate with a network; a processor coupled to the one or more network interfaces and configured to execute a process; and a memory configured to store the process executable by the processor, the process when executed configured to: determine a first channel hopping schedule for the apparatus to receive unicast communications from one or more neighbors of the apparatus, wherein the first channel hopping schedule differs from channel hopping schedules used by the one or more neighbors to receive unicast communications; determine a common second channel hopping schedule for the apparatus for network discovery that includes channels that are common to the apparatus and the one or more neighbors at every given point in time, wherein the second channel hopping schedule is based on parameters that are preconfigured across the device and the one or more neighbors prior to deployment, and wherein the same common second channel hopping schedule is self-generated by each of the device and the one or more neighbors based on the preconfigured parameters and without aid of a coordinating device; switch from the first channel hopping schedule to the second channel hopping schedule, in response to a network event; and cause a particular neighbor to join the network using the second channel hopping schedule. ### Claim 13 (depends on 12) The apparatus as in claim 12, wherein the network event is a power outage event in the network. ### Claim 14 (depends on 12) The apparatus as in claim 12, wherein the apparatus causes the particular neighbor to join the network using the second channel hopping schedule by: sending a beacon to the particular neighbor using one of the common channels. ### Claim 15 (depends on 12) The apparatus as in claim 12, wherein the process when executed is further operable to: receive a power restoration notification from the particular neighbor using one of the common channels. ### Claim 16 (depends on 12) The apparatus as in claim 12, wherein the process when executed is further operable to: notify one or more of the neighbors of the apparatus as to when the apparatus is going to switch from the first channel hopping schedule to the second channel hopping schedule. ### Claim 17 (depends on 12) The apparatus as in claim 12, wherein the network event comprises receiving an instruction to switch channel hopping schedules. ### Claim 18 (depends on 12) The apparatus as in claim 12, wherein the apparatus further comprises a real time clock, and wherein the second channel hopping schedule is determined based in part on the real time clock. ### Claim 19 (depends on 18) The apparatus as in claim 18, wherein the second channel hopping schedule is determined based further in part on a deployment identifier. ### Claim 20 (depends on 12) The apparatus as in claim 12, wherein channels in the first channel hopping schedule are hopped more frequently than the common channels are hopped in the second channel hopping schedule. ### Claim 21 (depends on 12) The apparatus as in claim 12, wherein the process when executed is further operable to: switch back to the first channel hopping schedule after the particular neighbor joins the network. ### Claim 22 (depends on 12) The apparatus as in claim 12, wherein the process when executed is further operable to: receive a beacon request from a portable device via a channel of the first channel hopping schedule and on behalf of one of the one or more neighbors; and provide a beacon using the first channel hopping schedule, in response to receiving the beacon request from the portable device. ### Claim 23 A tangible, non-transitory, computer-readable media having software encoded thereon, the software when executed by a processor of a device configured to: determine a first channel hopping schedule for the device to receive unicast communications from one or more neighbors of the device, wherein the first channel hopping schedule differs from channel hopping schedules used by the one or more neighbors to receive unicast communications; determine a common second channel hopping schedule for the device for network discovery that includes channels that are common to the device and the one or more neighbors at every given point in time, wherein the second channel hopping schedule is based on parameters that are preconfigured across the device and the one or more neighbors prior to deployment, and wherein the same common second channel hopping schedule is self-generated by each of the device and the one or more neighbors based on the preconfigured parameters and without aid of a coordinating device; switch from the first channel hopping schedule to the second channel hopping schedule, in response to a network event; and cause a particular neighbor to join the network using the second channel hopping schedule.