# US 10,772,095 B1 · Optimized unicast and broadcast communication in TSCH primary and secondary networks

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- Number: US 10,772,095 B1
- Document ID: US10772095B1
- Status: Granted
- Kind: B1
- Application number: 16/359,490
- Filed: 2019-03-20
- Published: 2020-09-24
- Granted: 2020-09-08
- Earliest claimed: 2019-03-20
- Assignees: Landis+Gyr Innovations, Inc.
- Applicants: Landis+Gyr Innovations, Inc.
- Inventors: James Patrick Hanley; Michael Sean Holcombe; Christopher Scott Hett; Lawrence Harris
- Web page: https://patentgrep.com/patent/US10772095B1

## CPC

- H04W 72/0446: Resources in time domain, e.g. slots or frames
- H04W 74/02: Hybrid access
- G05B 19/4185: {characterised by the network communication}
- H04L 5/0005: {Time-frequency}
- H04L 12/283: {Processing of data at an internetworking point of a home automation network}
- H04L 67/12: specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
- H04L 69/26: {Special purpose or proprietary protocols or architectures (network applications for proprietary or special purpose networking environments H04L67/12)}
- H04W 4/70: Services for machine-to-machine communication [M2M] or machine type communication [MTC]
- H04W 8/22: Processing or transfer of terminal data, e.g. status or physical capabilities
- H04W 28/021: {in wireless networks with changing topologies, e.g. ad-hoc networks (self-organizing networks H04W84/18)}
- H04W 40/244: {using a network of reference devices, e.g. beaconing}
- H04W 56/001: {Synchronization between nodes}
- H04W 72/0453: Resources in frequency domain, e.g. a carrier in FDMA
- H04W 72/30: Resource management for broadcast services
- H04W 74/0808: using carrier sensing, e.g. carrier sense multiple access [CSMA]
- H04L 2012/2841: {Wireless}
- 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 80/02: Data link layer protocols
- H04W 84/18: Self-organising networks, e.g. ad-hoc networks or sensor networks
- H04W 92/02: Inter-networking arrangements
- Y02D 30/70: in wireless communication networks
- Y04S 20/30: Smart metering, e.g. specially adapted for remote reading
- Y04S 40/18: Network protocols supporting networked applications, e.g. including control of end-device applications over a network
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- 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
- Y04S: SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS

## Abstract

A method for transmitting unicast messages includes: obtaining, by a first node configured to communicate on a primary time-slotted channel hopping (TSCH) network, a media access control (MAC) address of a second node configured to communicate on the primary TSCH network; determining whether the first node and the second node are also configured to communicate on a secondary TSCH network; and in response to determining that the first node and the second node are also configured to communicate on the secondary TSCH network: offsetting transmission of a unicast message until a second portion of a timeslot for the primary TSCH network; synchronizing to a channel hopping sequence and frequency of the secondary TSCH network for the second node, and transmitting, by the first node, the unicast message to the second node on the secondary TSCH network during the second portion of the timeslot.

## Claims

### Claim 1

A method for transmitting unicast messages, the method comprising:
determining, by a first node, to transmit a unicast message to a second node;
obtaining, by the first node configured to communicate on a primary time-slotted channel hopping (TSCH) network, a media access control (MAC) address of the second node configured to communicate on the primary TSCH network;
determining whether the first node and the second node are also configured to communicate on a secondary TSCH network; and
in response to determining that the first node and the second node are also configured to communicate on the secondary TSCH network:
offsetting transmission of the unicast message until a second portion of a timeslot for the primary TSCH network;
synchronizing to a channel hopping sequence and frequency of the secondary TSCH network for the second node, and
transmitting, by the first node, the unicast message to the second node on the secondary TSCH network during the second portion of the timeslot.

### Claim 2 (depends on 1)

The method of claim 1, wherein the first node offsets transmission of the unicast message during the timeslot for a specified delay period,
wherein offsetting transmission for the specified delay period causes the first node to transmit the unicast message during the second portion of the timeslot when the second node is listening on the secondary TSCH network.

### Claim 3 (depends on 2)

The method of claim 2, wherein the specified delay period is determined as a macTsTxOffset time period plus an additional macTsCCAOffset time period plus a macTsRxWait time period,
wherein the macTsTxOffset time period is a period of time a sender node waits to transmit a frame to make communication possible when the sender node is ahead in time of a receiver node, the additional macTsCCAOffset time period is a period of time to allow clear channel assessment after the macTsTxOffset time period, and the macTsRxWait time period is a period of time the receiver node waits to start receiving the frame after the receiver node starts listening to a transmission medium.

### Claim 4 (depends on 2)

The method of claim 2, wherein a primary portion of the timeslot is prioritized for transmitting broadcast/multicast messages.

### Claim 5 (depends on 1)

The method of claim 1, wherein the MAC address of the second node is associated with the channel hopping sequence of the second node on the secondary TSCH network, and
wherein the first node determines the channel on the secondary TSCH network to transmit the unicast message to the second node based the channel hopping sequence associated with the MAC address of the second node contained in a neighbor table stored in a memory of the first node.

### Claim 6 (depends on 1)

The method of claim 1, wherein prior to transmitting the unicast message to the second node, the first node receives a communication from the second node over the primary TSCH network, wherein the communication contains a capability information element indicating that the second node supports communication over the secondary TSCH network.

### Claim 7 (depends on 1)

The method of claim 1, wherein a channel hopping protocol of the secondary TSCH network switches frequencies less often than a channel hopping protocol of the primary TSCH network switches frequencies.

### Claim 8 (depends on 1)

The method of claim 1, wherein a channel hopping protocol of the secondary TSCH network switches frequencies at a same rate as a channel hopping protocol of the primary TSCH network switches frequencies.

### Claim 9 (depends on 1)

The method of claim 1, further comprising:
in response to determining that the first node and the second node are only configured to communicate on the primary TSCH network, transmitting the unicast message during a primary portion of the timeslot, wherein the timeslot is a contention access period timeslot for the primary TSCH network.

### Claim 10

A time-slotted channel hopping (TSCH) network node, comprising:
a transceiver;
a memory; and
a processor communicatively coupled to the transceiver and the memory, wherein the processor is configured to implement a protocol stack including:
a media access control (MAC) layer having a MAC address to communicate on a primary TSCH network, wherein the MAC address defines addressing for the primary TSCH network and a secondary TSCH network,
wherein the processor is further configured to:
refer to a neighbor table stored in the memory of the TSCH network node to obtain the MAC address of a second TSCH network node,
after a delay period of a first portion of a primary TSCH network timeslot cause the transceiver of the TSCH network node to:
synchronize to a channel hopping sequence and frequency of the secondary TSCH network, and
transmit a unicast frame to the second TSCH network node on the secondary TSCH network during a second portion of the primary TSCH network timeslot.

### Claim 11 (depends on 10)

The TSCH network node of claim 10, wherein the processor is configured to determine the delay period as a macTsTxOffset time period plus an additional macTsCCAOffset time period plus a macTsRxWait time period,
wherein the macTsTxOffset time period is a period of time a sender node waits to transmit a frame to make communication possible when the sender node is ahead in time of a receiver node, the additional macTsCCAOffset time period is a period of time to allow clear channel assessment after the macTsTxOffset time period, and the macTsRxWait time period is a period of time the receiver node waits to start receiving the frame after the receiver node starts listening to a transmission medium.

### Claim 12 (depends on 10)

The TSCH network node of claim 10, wherein the MAC address of the second TSCH network node is associated with the channel hopping sequence of the second TSCH network node on the secondary TSCH network, and
wherein the TSCH network node determines a channel on the secondary TSCH network to transmit the unicast frame to the second TSCH network node based the channel hopping sequence associated with the MAC address of the second TSCH network node on the secondary TSCH network contained in the neighbor table stored in the memory of the TSCH network node.

### Claim 13 (depends on 10)

The TSCH network node of claim 10, the processor is configured to:
prior to transmitting the unicast frame to the second TSCH network node, receive a communication from the second TSCH network node over the primary TSCH network, wherein the communication contains a capability information element indicating that the second TSCH network node supports communication over the secondary TSCH network, and
store an indication corresponding to the capability information element in an entry associated with the second TSCH network node in the neighbor table in the memory of the TSCH network node.

### Claim 14 (depends on 10)

The TSCH network node of claim 10, wherein the processor is configured to cause the transceiver to broadcast a communication over the primary TSCH network including a capability information element indicating that the TSCH network node supports communication over the secondary TSCH network.

### Claim 15

A system comprising:
a plurality of time-slotted channel hopping (TSCH) nodes communicatively coupled to each other on a primary TSCH network, each of the TSCH nodes of the plurality of TSCH nodes including:
a transceiver;
a memory; and
a processor communicatively coupled to the transceiver and the memory, wherein the processor is configured to implement a protocol stack including:
a media access control (MAC) layer having a MAC address to communicate on the primary TSCH network, wherein the MAC address defines addressing for the primary TSCH network and a secondary TSCH network,
wherein the processor of a first TSCH node of the plurality of TSCH nodes is further configured to:
cause the transceiver of the first TSCH node to receive a first communication from a second TSCH node of the plurality of TSCH nodes over the primary TSCH network containing a capability information element indicating that the second TSCH node supports communication over the secondary TSCH network,
cause the transceiver of the first TSCH node to synchronize to a channel hopping sequence and frequency of the secondary TSCH network, and
after a delay period of a first portion of a primary TSCH network timeslot, cause the transceiver of the first TSCH node to transmit a unicast frame to the second TSCH node on the secondary TSCH network during a second portion of the primary TSCH network timeslot.

### Claim 16 (depends on 15)

The system of claim 15, wherein the processor of each of the TSCH nodes of the plurality of TSCH nodes is configured to store in a neighbor table indications corresponding to the capability information element received in communications from other TSCH nodes,
wherein the capability information element indicates that the other TSCH nodes support communication over the secondary TSCH network.

### Claim 17 (depends on 15)

The system of claim 15, wherein the processor of each of the TSCH nodes of the plurality of TSCH nodes is configured to cause the transceiver to broadcast a second communication over the primary TSCH network including the capability information element indicating that the TSCH node supports communication over the secondary TSCH network.

### Claim 18 (depends on 15)

The system of claim 15, wherein delaying transmission for the delay period causes the transceiver of the first TSCH node to transmit the unicast frame after a primary portion of the primary TSCH timeslot elapses.

### Claim 19 (depends on 15)

The system of claim 15, wherein the processor of the first TSCH node of the plurality of TSCH nodes is configured to determine the delay period as a macTsTxOffset time period plus an additional macTsCCAOffset time period plus a macTsRxWait time period,
wherein the macTsTxOffset time period is a period of time a sender node waits to transmit a frame to make communication possible when the sender node is ahead in time of a receiver node, the additional macTsCCAOffset time period is a period of time to allow clear channel assessment after the macTsTxOffset time period, and the macTsRxWait time period is a period of time the receiver node waits to start receiving the frame after the receiver node starts listening to a transmission medium.

### Claim 20 (depends on 15)

The system of claim 15, wherein the MAC address of the second TSCH node is associated with the channel hopping sequence of the second TSCH node on the secondary TSCH network, and
wherein the first TSCH node determines a channel on the secondary TSCH network to transmit the unicast frame to the second TSCH node based the channel hopping sequence associated with the MAC address of the second TSCH node contained in a neighbor table stored in the memory of the first TSCH node.

### Claim 21 (depends on 15)

The system of claim 15, wherein a primary portion of the primary TSCH timeslot is prioritized for transmitting broadcast/multicast frames.

### Claim 22 (depends on 15)

The system of claim 15, wherein a channel hopping protocol of the secondary TSCH network switches frequencies less often than a channel hopping protocol of the primary TSCH network switches frequencies.

### Claim 23 (depends on 15)

The system of claim 15, wherein a channel hopping protocol of the secondary TSCH network switches frequencies at a same rate as a channel hopping protocol of the primary TSCH network switches frequencies.