AU2024202460A1 - Downlink event allocation in a network - Google Patents
Downlink event allocation in a network Download PDFInfo
- Publication number
- AU2024202460A1 AU2024202460A1 AU2024202460A AU2024202460A AU2024202460A1 AU 2024202460 A1 AU2024202460 A1 AU 2024202460A1 AU 2024202460 A AU2024202460 A AU 2024202460A AU 2024202460 A AU2024202460 A AU 2024202460A AU 2024202460 A1 AU2024202460 A1 AU 2024202460A1
- Authority
- AU
- Australia
- Prior art keywords
- devices
- event start
- time
- schedule
- event
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 claims abstract description 111
- 230000005540 biological transmission Effects 0.000 claims abstract description 105
- 238000004891 communication Methods 0.000 claims abstract description 61
- 238000009826 distribution Methods 0.000 claims description 51
- 230000015654 memory Effects 0.000 claims description 39
- 230000007958 sleep Effects 0.000 abstract description 46
- 230000006870 function Effects 0.000 abstract description 5
- 230000000737 periodic effect Effects 0.000 abstract description 4
- 238000010586 diagram Methods 0.000 description 27
- 230000000694 effects Effects 0.000 description 14
- 230000005611 electricity Effects 0.000 description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 10
- 239000007789 gas Substances 0.000 description 9
- 238000003860 storage Methods 0.000 description 8
- 238000012545 processing Methods 0.000 description 7
- 238000005516 engineering process Methods 0.000 description 5
- 230000001413 cellular effect Effects 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 238000001228 spectrum Methods 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 238000012937 correction Methods 0.000 description 2
- 238000013523 data management Methods 0.000 description 2
- 238000007726 management method Methods 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 238000009827 uniform distribution Methods 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- SOZVEOGRIFZGRO-UHFFFAOYSA-N [Li].ClS(Cl)=O Chemical compound [Li].ClS(Cl)=O SOZVEOGRIFZGRO-UHFFFAOYSA-N 0.000 description 1
- KLARSDUHONHPRF-UHFFFAOYSA-N [Li].[Mn] Chemical compound [Li].[Mn] KLARSDUHONHPRF-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 238000013475 authorization Methods 0.000 description 1
- 238000013480 data collection Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 230000008520 organization Effects 0.000 description 1
- 230000010363 phase shift Effects 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 230000002618 waking effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W72/00—Local resource management
- H04W72/12—Wireless traffic scheduling
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- 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
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
Downlink event allocation in a network
Abstract
Techniques for allocating event offsets within a period of transmission are described. A mains
powered device (MPD) may act as a "parent" to one or more battery-powered devices (BPDs). The
MPD may assign "event offsets" to each BPD. The event offset is a time by which the BPD's timeslot
is "offset" from the start of a periodic cycle of transmissions by the MPD. Thus, each event offset
indicates a time that the BPD must be "awake," i.e., operating its radio receiver and/or performing
other functionality. A BPD may spend a substantial fraction of its time in a "sleep" mode, wherein less
power is used and fewer functions are performed than during a period of that BPD's event offset.
Another BPD may have a different event offset. Communications by the MPD with each child BPD
may be substantially uniformly distributed over the period. To increase efficiency, groups ofBPDs
may receive multicasts.
43890127_1
Description
[0001] This application is a divisional application of Australian Patent Application No. 2020375024, a national phase entry of International Application No. PCT/US2020/058289 filed October 2020, which claims priority to U.S. Patent Application Serial No. 16/670,046, filed October 31, 2019, titled "Downlink Event Allocation in a Network" and U.S. Patent Application Serial No. 16/670,137, filed October 31, 2019, titled "Downlink Event Allocation in a Network," each of which are incorporated in their entirety herein by reference. BACKGROUND
[0002] In a wireless network environment, both battery-powered devices and mains- powered devices may send and receive packets. While conservation of electricity in the operation of mains-powered devices is not usually a critical design parameter, battery- powered devices face significant constraints due to their limited available power. In some network environments, such as water and gas metering devices, the expected lifespan of a battery may be 20 years. Accordingly, techniques that make the most of available power are desirable. SUMMARY
[0002a] It is an object of the present invention to substantially overcome, or at least ameliorate, at least one disadvantage of present arrangements.
[0002b] One aspect of the present disclosure provides a method, comprising: transmitting, according to a schedule, a broadcast transmission to a plurality of devices at a first event start time offset from among a plurality of event start-time offsets indicated by the schedule; transmitting, according to the schedule, a first unicast transmission to a device of the plurality of devices at a second time indicated by a second event start-time offset from among the plurality of event start-time offsets indicated by the schedule; transmitting, according to the schedule, a plurality of unicast transmissions to the plurality of devices, wherein a distribution of numbers of devices associated with event start-time offsets dedicated to unicast transmissions is substantially uniform; and transmitting, according to the schedule, a multicast transmission to at least two devices of the plurality of devices, wherein the multicast transmission is sent at a third time indicated by a third event start-time offset from among the plurality of event start-time offsets.
[0002c] Another aspect of the present disclosure provides a mains-powered device comprising: one or more processors; and memory communicatively coupled to the one or more processors, the memory storing thereon processor-executable instruction that, when executed by the one or more processors, perform operations comprising: transmitting, according to a schedule, a
1a
broadcast transmission to a plurality of devices at a first event start-time offset from among a plurality of event start-time offsets indicated by the schedule; transmitting, according to the schedule, a first unicast transmission to a device of the plurality of devices at a second time indicated by a second event start-time offset from among the plurality of event start-time offsets indicated by the schedule; transmitting, according to the schedule, a plurality of unicast transmissions to the plurality of devices, wherein a distribution of numbers of devices associated with event start-time offsets dedicated to unicast transmissions is substantially uniform; and transmitting, according to the schedule, a multicast transmission to at least two devices of the plurality of devices, wherein the multicast transmission is sent at a third time indicated by a third event start-time offset from among the plurality of event start-time offsets.
[0002d] Another aspect of the present disclosure provides non-transitory computer-readable media storing thereon processor executable instructions that, when executed by one or more processors, cause the one or more processors to perform operations comprising: transmitting, according to a schedule, a broadcast transmission to a plurality of devices at a first event start time offset from among a plurality of event start-time offsets indicated by the schedule; transmitting, according to the schedule, a first unicast transmission to a device of the plurality of devices at a second time indicated by a second event start-time offset from among the plurality of event start-time offsets indicated by the schedule; transmitting, according to the schedule, a plurality of unicast transmissions to the plurality of devices, wherein a distribution of numbers of devices associated with event start-time offsets dedicated to unicast transmissions is substantially uniform; and transmitting, according to the schedule, a multicast transmission to at least two devices of the plurality of devices, wherein the multicast transmission is sent at a third time indicated by a third event start-time offset from among the plurality of event start-time offsets. BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components. Moreover, the figures are intended to illustrate general concepts, and not to indicate required and/or necessary elements.
[0004] FIG. 1 is a schematic diagram of an example network architecture.
[0005] FIG. 2 is a diagram showing details of an example mains-powered device.
[0006] FIG. 3 is a diagram showing details of an example battery-powered device.
[0007] FIG. 4 is a timing diagram showing example downlink event allocation and showing an example period of time and event offsets within that period of time.
[00081 FIG. 5 is a timing diagram showing an example period of time after inclusion of
additional event offsets resulting in each event offset being shortened.
[00091 FIG. 6 is a diagram illustrating an example listening event offset.
[000101 FIG. 7 is a diagram showing example combination of event start-time offsets within
a schedule used by two groups of battery-powered devices having different sleep/wake cycle
lengths.
[00101 FIG. 8 is a flow diagram showing example techniques for communication with a
plurality of battery-powered devices (BPDs) using an event offset associated with each BPD
within a period of time.
[00111 FIG. 9 is a flow diagram showing example techniques for selection and/or adjustment
of a number of event offsets to be used within a period of time.
[00121 FIG. 10 is a flow diagram showing example techniques for joining a device to a
network.
[00131 FIG. 11 is a flow diagram showing example techniques for removing a device from a
network.
[00141 FIG. 12 is a flow diagram showing example techniques for transmitting to devices in a
network according to a schedule where messages exceed a length of a timeslot.
[00151 FIG. 13 is a flow diagram showing example techniques for transmitting to devices in a
network according to high-power use states and low-power use states.
[00161 FIG. 14 is a flow diagram showing example techniques for broadcast and unicast events.
[00171 FIG. 15 is a flow diagram showing example techniques for adding devices to a network.
[00181 FIG. 16 is a flow diagram showing example techniques for building a schedule of
timeslots consistent with two groups of battery-powered devices with different sleep/wake
periods.
[00191 FIG. 17 is a flow diagram showing four example techniques for allocating devices to
particular event start-time offsets (i.e., timeslots).
[00201 FIG. 18 is a flow diagram showing example techniques for removing devices from a
network.
[00211 FIG. 19 is a flow diagram showing example techniques for adding a device to a network.
[00221 FIG. 20 is a flow diagram showing example techniques for constructing a schedule used for communication with groups of battery-powered devices (BPDs) having different activity
cycles of wake (higher-power use) and sleep (lower-power use) periods.
Overview
[00231 A wireless network of devices may include one or more mains-powered device (MPD) and one or more battery-powered device (BPD). The MPDs are connected to an electrical power
grid, and their radio usage and processing abilities are not limited by the availability of
electricity, whereas the BPDs are constrained to the electricity provided by their batteries.
[00241 In one example, each BPD has a "parent" device that is an MPD. In the example, each MPD may be associatedwith one or more "child" BPDs, and may assign "event offsets" to each
of its child BPD node(s). The event offsets are a time by which the BPD's timeslot is "offset"
from the start of a periodic cycle of transmissions. Thus, each event offset indicates a time that
the BPD is scheduled to be "awake," i.e., operating its radio receiver and/or performing other
functionality. Another BPD may have a different event offset. Accordingly, communications
by the MPD with each child BPD is spread over the period of time. Techniques for uniformly
distributing communications with the BPDs over the period are described. In an example, a
BPD may spend a substantial fraction of its time in a "sleep" mode, wherein less power is used
and fewer functions are performed than during a period associated with that BPD's event offset,
thus allowing the BPDs to conserve electricity.
[00251 Example events may include at least a time during which the BPD is able to receive information, e.g., data and/or a command, etc., and perhaps send information over the wireless
network. The time of the event may include a start time, and possibly an end time and/or
duration of the event. The event may include the transfer of information from the BPD to the
MPD, or the reverse, etc. In a further example, an MPD assigns event offsets to each BPD in a
manner that minimizes overlap in time and provides a start-time and/or time-period for one- or two-way unicast transmission to each BPD. In some examples, two or more BPDs may be associated with a multicast and/or broadcast event timed according to one or more event offsets.
The use of event offsets reduces the amount of time during which the BPDs need to be "awake"
to receive radio signals and allows the BPDs to turn on a radio in a just-in-time manner.
[0026] In an example, event offsets that are used during the period of time to manage timing
of transmission of messages to devices on a network are spread substantially uniformly among
the plurality of event offsets. Thus, some event offsets may be used by the MIPD for
communication with BPDs. However, other event offsets may not be used (e.g., if there are
more event offsets than BPD associated with an MPD). In such a situation, the event offsets to
be used may be selected to time communications between devices in a manner that distributes
the communications over the period of time such that their variance (e.g., the variance of the
distribution of the used event offsets within the period of time) is less than a threshold value.
[0027] Some event offsets may be used for broadcast and multicast groups. In an example,
such event offsets may be selected to be at the beginning of a period of time. Remaining event
offsets are used for unicast transmissions. If a number of the remaining event offsets is less than
the number of devices in a network associated with a particular "parent" device (e.g., anMIPD),
some event offsets may be associated with a number (e.g., "x") of devices and other event offsets
maybe associated with the number plus one (e.g., "x+1") devices. In such a situation, the event
offsets to be used once more than other event offsets may be selected to time communications
between devices in a manner that distributes the communications over the period of time such
that the variance of the distribution (e.g., the variance of the distribution of the used event offsets
within the period of time) is less than a same or different threshold value.
[0028] In examples, MPDs and BPDs may be deployed in different network types. Such
network types may include mesh networks, star networks, and/or hybrid networks having mesh
and star characteristics and/or portions. An event may include a broadcast event to a plurality
of BPDs. An event may include a multicast to a plurality or group of BPDs. An event may
include a unicast transmission to, or series of messages between, MPD(s) and/or BPD(s). In an
example, the BPDs are utility meters, such as gas or water meters. The MIPD(s) may be relay devices, electric metering devices, dedicated communications devices, etc. In a more specific example, the MPD(s) may be electricity meters, which relay data from BPDs that may be water meters, gas meters, or other devices.
[00291 Each mains-powered device may transmit and receive information in periodic manner. In an example, the MPD may perform one- or two-way communications and/or other events
with a series of BPDs. The communications and/or events may be performed in a sequence over
a period of time. Within the period, a plurality of BPD each have their event offset from the start
of the period, within which they communicate with the MPD. A schedule of event offsets within
the period of time may be used to coordinate a plurality of events, including event timing, event
sequence and ordering, event distribution over the period (e.g., substantially uniform distribution
and/or variance of event distribution under a threshold value), etc. During additional and
subsequent periods of time, the communications and/or events may be repeated.
Example Environment
[00301 FIG. 1 shows an example networked environment or architecture 100. The architecture
100 includes multiple network communication devices. The network communication devices
include MPD mains-powered devices (MPD) 102(1), 102(2), 102(3), 102(4), . . 102(M)
(collectively referred to as "MPDs 102"), and BPD battery-powered devices (BPDs) 104(1),
104(2), 104(3), . . 104(N) (collectively referred to as "BPDs 104"), where M and N are any
integers greater than or equal to 1 and may be the same number or different numbers. In some
illustrations, the MPDs 102 include more functionality/resources than the BPDs 104. In one
example, the MPDs 102 are implemented as mains-powered devices (MPDs) that are connected
to mains electricity (e.g., electricity meters), while the BPDs 104 are implemented as battery
powered devices (BPDs) that are not connected to mains electricity (e.g., water meters, gas
meters, etc. that employ batteries). However, in other examples, the MPDs 102 and BPDs 104
may have different processing power, processing capabilities, and so on. The techniques
discussed herein may be implemented to communicate between MPDs 102, BPDs 104, or any
combination of devices.
[0031] The network communication devices are in communication with one another via an area network (AN) 106. As used herein, the term "area network" refers to a defined group of devices
that are in communication with one another via one or more wired or wireless links. Examples
of area networks include, for example, local area networks (LANs), neighborhood area networks
(NANs), personal area networks (PANs), home area networks (HANs), field area networks
(FANs), or the like. While only one AN 106 is shown in FIG. 1, in practice, multiple ANs may
exist and may collectively define a larger network, such as an advanced metering infrastructure
(AMI) of a utility communication network. At any given time, each individual device may be a
member of a particular AN. Over time, however, devices may migrate from one AN to another
geographically proximate or overlapping AN based on a variety of factors, such as respective
loads on the ANs, battery reserves, interference, etc.
[0032] The term "link" refers to a direct communication path between two devices (without passing through or being relayed by another device). A link may be over a wired or wireless
radio frequency (RF) communication path. Each link may represent a plurality of channels over
which a device is able to transmit or receive data. Each of the plurality of channels may be
defined by a frequency range which is the same or different for each of the plurality of channels.
In some instances, the plurality of channels comprises RF channels. The AN 106 may
implement a channel hopping sequence, such that a channel may change over time. Although
many examples discussed herein implement a plurality of channels as data channels, in some
instances the plurality of channels include a control channel that is designated for
communicating messages to specify a data channel to be utilized to transfer data. Transmissions
on the control channel may be shorter relative to transmissions on the data channels.
[0033] The AN 106 may comprise a mesh network, in which the network communication devices relay data through the AN 106. Alternatively, or additionally, the area network 106 may
comprise a star network, in which a central device acts a parent to one or more children devices.
For example, the MPD 102(M) may act as a parent to the BPDs 104(1), 104(2), and 104(3).
Further, in some instances the AN 106 may include a portion that is implemented as a mesh
network and a portion that is implemented as a star network. Moreover, in other instances the
AN 106 may be implemented in whole or part by other types of networks, such as hub-and
spoke networks, mobile networks, cellular networks, etc. In some instances, a device may be
able to communicate with multiple different types of networks (e.g., a mesh network and a star
network) at the same or different times. For instance, if a device is unable to discover a suitable
device in a mesh network mode, the device may attempt to connect to a nearby star network,
mobile data collection network, or cellular network. Regardless of the topology of the AN 106,
individual network communication devices may communicate by wireless (e.g., radio
frequency) and/or wired (e.g., power line communication, Ethernet, serial, etc.) connections.
[0034] In many examples, the BPDs 104 are implemented as leaf nodes. A leaf node may
generally communicate with a parent node and not relay data for another node. As illustrated in
FIG. 1, the BPDs 104(1) and 104(2) act as leaf nodes, with theMPD 102(M) being the parent
node. However, in other examples the BPDs 104 may relay data for other nodes. For instance,
the BPD 104(3) may relay data for the BPD 104(N). Further, any type of device may be
implemented as a leaf node (e.g., any of theMPDs 102).
[0035] The communication network 100 may also include an edge device 108, which serves
as a connection point of the AN 106 to one or more networks 110 (e.g., a backhaul network),
such as the internet. The edge device 108 may include, but is not limited to, a field area router
(FAR), a cellular relay, a cellular router, an edge router, a DODAG (Destination Oriented
Directed Acyclic Graph) root, a root device or node of the AN, a combination of the foregoing,
etc. In this illustrated example, the edge device 108 comprises a FAR, which relays communions
from the AN 106 to one or more service providers 112 via the network(s) 110.
[0036] In some instances, the one or more service providers 112 comprise one or more central
office computing systems that include a security service such as authentication, authorization
and accounting (AAA) server, a network registration service such as dynamic host configuration
protocol (DHCP) server, a network management service (NMS), a collection engine (CE), a
meter data management system (in the utility context), a customer relationship management
system (in the sales context), a diagnostic system (in a manufacturing context), an inventory
system (in a warehouse context), a patient record system (in the healthcare context), a billing system, etc. The network communication devices may register or interact with some or all these one or more central office systems. In one example, the one or more central office systems may implement a meter data management system to collect resource consumption data from the network communication devices of the AN 106, process the resource consumption data, provide data regarding resource consumption to customers, utilities, and others, and/or perform a variety of other functionality. In other instances, the one or more service providers 112 comprise other systems to implement other functionality, such as web services, cloud services, and so on. In yet other instances, the one or more service providers 112 may be implemented as other types of devices, such as in the context of the internet of things (IoT) that allows a variety of devices to exchange data.
[00371 The one or more service providers and/or their computing systems 112 may be
physically located in a single central location, or may be distributed at multiple different
locations. The one or more service providers 112 may be hosted privately by an entity
administering all or part of the communications network (e.g., a utility company, a governmental
body, distributor, a retailer, manufacturer, etc.), or may be hosted in a cloud environment, or a
combination of privately hosted and cloud hosted services.
[00381 In many instances, a battery-powered device (BPD) may connect to a network by
connecting directly with MPD mains-powered device (MPD). To illustrate, a battery-powered
water meter, for example, the BPD 104(1), discovers in its vicinity an electricity meter, theMPD
102(M), connected to mains power. Because the MPD 102(M) is connected to mains power, it
has no practical energy constraints. The BPD 104(1) may associate the MPD 102(M) as its
parent, in which case the MPD 102(M) acts as the connecting point between the BPD 104(1)
and the one or more service providers 112.
[00391 In other instances, an BPD can connect to a network via an BPD that acts as a relay (an
BPD relay). To illustrate, the BPD 104(N) may be a gas meter, which discovers a battery
powered water meter, the BPD 104(3), which is already connected to the AN 106 via theMPD
102(M) and can play the role of an BPD relay. Accordingly, the nodes 104(3) and 104(N) form
an example mesh network 114 within a star network centered at the MPD 102(M). The BPD
104(N) may associate this BPD-relay, the BPD 104(3), as its parent to get connected to the
AN 106. In yet further instances, an BPD may connect to other networks and/or connect in other
manners.
[00401 A schedule of event offsets 116 may be used by theMPD and the BPD (e.g., mains
powered device and battery-powered devices, respectively). By using the schedule, the MPDs
and the BPDs may recognize different event offsets and associated events within a period of
time. The schedule of event offsets 116 may show event starting points according to offsets in
time from the beginning of the period of time. The schedule of event offsets 116 may be used
to coordinate a plurality of events, including event timing, event sequence and ordering, event
distribution over the period (e.g., substantially uniform distribution and/or having a variance of
event distribution under a threshold value), etc. During additional and subsequent periods of
time, the communications and/or events may be repeated, such as by repeated reference to the
schedule of event offsets 116.
Example Network Communications Devices
[00411 FIG. 2 is a diagram showing details of an example mains-powered device 200
(MPDMPD). In this example, MPD 200 comprises a device that is connected to mains power,
such as an electricity meter, sensor, etc. However, as discussed above,MPDs can take numerous
different forms, depending on the industry and context in which they are deployed. Different
types of MPDs may have different physical and/or logical components. For instance, utility
meter MPDs such as that shown in FIG. 2A may have metrology components, whereas other
types of MPDs may not.
[00421 As shown in FIG. 2, the example MPD 200 includes a processing unit 202, a transceiver
204 (e.g., radio), one or more metrology devices 206, and an alternating current (AC) driven
power supply 208 that couples to the AC mains power line wherein theMPD 200 is installed.
The processing unit 202 may include one or more processors 210 and memory 212. When
present, the one or more processors 210 may comprise microprocessors, central processing units,
graphics processing units, or other processors usable to execute program instructions to implement the functionality described herein. Additionally, or alternatively, in some examples, some or all the functions described may be performed in hardware, such as an application specific integrated circuit (ASIC), a gate array, or other hardware-based logic device.
[00431 The transceiver 204 may comprise one or more hardware and/or software implemented radios to provide two-way RF communication with other network communication devices in the
AN 106 and/or other computing devices via the network 110. The transceiver 204 may
additionally or alternatively include a modem to provide power line communication (PLC)
communication with other network communication devices that are connected to an electrical
service grid.
[00441 The metrology device(s) 206 comprise the physical hardware and sensors to measure
consumption data of a resource (e.g., electricity, water, or gas) at a site of the meter. In the case
of an electric meter, for example, the metrology device(s) 206 may include one or more Hall
effect sensors, shunts, etc. In the case of water and gas meters, the metrology device(s) 206 may
comprise various flow meters, pressure sensors, etc. The metrology device(s) 206 may report
the consumption data to the one or more service providers 112 via the transceiver 204. The
consumption data may be formatted and/or packetized in a manner, protocol and/or modulation
scheme for transmission.
[00451 The memory 212 includes an operating system (OS) 214 and one or more applications 216 that are executable by the one or more processors 210. The memory 212 may also include
one or more metrology drivers 218 configured to receive, interpret, and/or otherwise process the
metrology data collected by the metrology device(s) 206. Additionally, or alternatively, one or
more of the applications 216 may be configured to receive and/or act on data collected by the
metrology device(s) 206.
[00461 The memory 212 may also include one or more communication stacks 220. In some examples, the communication stack(s) 220 may be configured to implement a 6LowPAN
protocol, an 802.15.4e (TDMA CSM/CA) protocol, an 802.15.4-2015 protocol, and/or another
protocol. However, in other examples, other protocols may be used, depending on the networks
with which the device is intended to be compatible. The communication stack(s) 220 describe the functionality and rules governing how the MPD 200 interacts with each of the specified types of networks. For instance, the communication stack(s) 220 may cause MIPDs and BPDs to operate in ways that minimize the battery consumption of BPDs when they are connected to these types of networks.
[00471 In some instances, the MPD 200 may be configured to send and/or receive communications on multiple channels simultaneously. For example, the transceiver(s) 204 may
be configured to receive data at the same time on hundreds of channels. Additionally, or
alternatively, the transceiver(s) 204 may be configured to send data at the same time on hundreds
of channels.
[00481 The schedule of event offsets 116 may include offset times (from the start of a period
of time) at which one or more "child" nodes expect a communication from the mains-powered
device. Using the schedule 116, the mains-powered device can communicate with a plurality of
battery-powered devices, using broadcast, multicast and/or unicast techniques, at appropriate
timed event offsets within a period of time.
[00491 FIG. 3 is a diagram showing details of an example battery-powered device 300. In this
example, BPD 300 comprises a device that is not connected to mains power. However, as
discussed above, BPDs can take numerous different forms, depending on the industry and
context in which they are deployed. Different types of BPDs may have different physical and/or
logical components. For instance, utility meter BPDs such as that shown in FIG. 3 may have
metrology components, whereas other types of BPDs may not.
[00501 The BPD 300 of FIG. 3 is similar in many respects to theMIPD 200. To the extent that the MPD 200 and BPD 300 include the same or similar components, the functions will not be
repeated here. Therefore, the following discussion of the BPD 300 focuses on the differences
between the BPD 300 and the MPD 200. However, the differences highlighted below should
not be considered to be exhaustive. One difference between the MPD 200 and the BPD 300 is
that the BPD 300 may include a battery 302 instead of the AC power supply 208. The specific
characteristics of the battery 302 may vary widely depending on the type of BPD. By way of
example and not limitation, the battery 302 may comprise a lithium thionyl chloride battery (e.g., a 3-volt battery having an internal impedance rated at 130 Ohms), a lithium manganese battery
(e.g., a 3-volt battery having an internal impedance rated at 15 Ohms), a lithium ion battery, a
lead-acid battery, an alkaline battery, etc.
[00511 Also, in some examples, even components with similar functions may be different for MPDs than for BPDs due to the different constraints. As one example, while both MPDs and
BPDs have transceivers, the specific transceivers used may be different. For instance, an MPD
transceiver may include a PLC modem while an BPD transceiver does not because the BPD is
not connected to an electrical power line that could be used for PLC communications.
Additionally, or alternatively, an BPD transceiver may employ a lower power RF radio to
minimize energy consumption. Further, other components of MPDs and BPDs may vary. In
some instances, BPDs are implemented with less functionality and/or include less hardware
components than the MPDs. Further, in some instances, components of BPDs are lower power
components than the corresponding components of the MPDs.
[00521 The memory 212 of the MPD 200 and BPD 300 is shown to include software functionality configured as one or more "modules." However, the modules are intended to
represent example divisions of the software for purposes of discussion and are not intended to
represent any type of requirement or required method, manner or necessary organization.
Accordingly, while various "modules" are discussed, their functionality and/or similar
functionality could be arranged differently (e.g., combined into a fewer number of modules,
broken into a larger number of modules, etc.).
[00531 The various memories described herein are examples of computer-readable media. Computer-readable media may take the form of volatile memory, such as random-access
memory (RAM) and/or non-volatile memory, such as read-only memory (ROM) or flash RAM.
Computer-readable media devices include volatile and non-volatile, removable and non
removable media implemented in any method or technology for storage of information such as
computer-readable instructions, data structures, program modules, or other data for execution
by one or more processors of a computing device. Examples of computer-readable media
include, but are not limited to, phase change memory pramM), static random-access memory
(SRAM), dynamic random-access memory (DRAM), other types of random access memory
(RAM), read-only memory (ROM), electrically erasable programmable read-only memory
(EEPROM), flash memory or other memory technology, compact disk read-only memory (CD
ROM), digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape,
magnetic disk storage or other magnetic storage devices, or any other non-transitory medium
that can be used to store information for access by a computing device. As defined herein,
computer-readable media does not include transitory media, such as modulated data signals and
carrier waves, and/or signals.
[00541 While detailed examples of certain computing devices (e.g., the MPD 200 and the BPD
300) are described herein, it should be understood that those computing devices may include
other components and/or be arranged differently. As noted above, in some instances a
computing device may include one or more processors and memory storing processor executable
instructions to implement the functionalities they are described as performing. Certain
computing devices may additionally or alternatively include one or more hardware components
(e.g., application specific integrated circuits, field programmable gate arrays, systems on a chip,
and the like) to implement some or all of the functionalities they are described as performing.
Further, in some examples a computing device may be implemented as that described in U.S.
Application No. 14/796,762, filed June 10, 2015 and titled "Network Discovery by Battery
Powered Devices," the entire contents of which are incorporated herein by reference.
[00551 By way of example and not limitation, the MPD 200 and/or the BPD 300 may
implement a variety of modulation schemes, techniques, and/or data rates, such as frequency
shift keying (FSK) 802.15.4g (e.g., mandatory mode with a data rate of 50 kbps or 75 kbps, no
forward error correction; legacy mode with a data rate of 150 kbps with forward error correction
code rate 1/2; option 2; etc.), offset quadrature phase-shift keying (OQPSK) modulation with
direct-sequence spread spectrum (DSSS) spreading, and so on. To implement these different
connection modes, a media access control (MAC) sub-layer of a device may be able to indicate
to a physical layer the modulation technique and data rate to be used for each transmission.
10056] In many instances, information that is included in an information element may be stored
in the memory 212 of the MIPD 200 and/or the BPD 300. For example, the memory 212 may
store any information regarding an operating context, such as schedule data, channel data, seed
data, timing data, and so on. In some instances, components of the MIPD 200 and/or the BPD
300 may reference the information to determine how to communicate according to a specific
operating context.
10057] The schedule of event offsets 116 may include offset times (from the start of a period
of time) at which the battery-powered device 300 may participate in an event offset, i.e., an event
that is offset from the start of a period of time by the offset amount. In an example, the device
300, i.e., a "child" device of a mains-powered device, can expect a communication from the
parent at a time indicated by the schedule. Using the schedule 116, the battery-powered child
device may communicate with the mains-powered device, using broadcast, multicast and/or
unicast techniques, using appropriate frequencies and modulation schemes, at timed event
offsets within a period of time. The schedule 116 of the battery-powered device may be a subset
of the schedule 116 of the mains-powered device, in that the schedule of the child device may
include only information relevant to the child device.
Example Downlink Event Allocation and Scheduling
10058] FIGS. 4 and 5 show example implementations of at least portions of the schedule 116.
Each example 400, 500 shows a plurality of event offsets, each of which may be used for one or
more of: timing event(s) (e.g., communications); indicating radio frequencies for use; indicating
modulation schemes for use; indicating participants of the event; and/or to indicate other data.
In an example, the event offset 404 may indicate an offset time, a radio frequency, a modulation
scheme, a mains-powered device, a battery-powered device, and a purpose for the
communication (e.g., for the battery-powered device to send natural gas consumption/quantity
data).
10059] FIG. 4 shows example techniques for downlink event offset allocation 400. In the
example, a period 402 (e.g., a period of time) is configured to include a plurality of event offsets
404-414. In example use of the downlink event allocation 400, a mains-powered device (MPD)
transmits over the period of time 402. Within the period of time 402, one or more of the event
offsets 404-414 are associated with one or more battery-powered devices (BPDs). The event
offsets 404-414 are periods of time that are "offset" from the beginning of the period 402. They
indicate "events," such as communication between the MPD and one or more BPDs and/or the
reasons for such communications. The BPDs are configured to listen in a periodic manner, such
that each BPD turns on its radio and/or other functionality (e.g., processor, memory, etc.) as
indicated by one or more event offsets associated with that BPD. In an example, a BPD may
participate in a broadcast event timed according to a first event offset. The broadcast event may
involve a data transmission from the MPD to a plurality of BPDs. The BPD may participate in
a multicast event timed according to a second event offset. The multicast event may involve a
plurality of BPDs communicating, in a receive-only or two-way manner, with the MPD. The
BPD may participate in a unicast event timed according to a third offset. The unicast event may
involve one-on-one, one- or two-way communication, between the MPD and the BPD.
[00601 In one example of techniques for downlink event allocation 400, the period of time 402
may be one minute long, although longer and shorter periods could be used in other examples.
In the example, each event offset 404-414 could be one-half second in length. In some examples,
the entire communication between the MPD and BPD(s) could be concluded within the period
of time of the event offset. In other examples, theMPD may communicate with one BPD on
one RF frequency at a time that starts at the event offset, but continues beyond the end of the
event offset. The MPD may communicate with a second BPD on a second RF frequency at a
time that starts at a different event offset, possibly overlapping somewhat in time. Accordingly,
a communication may start at the beginning of an event offset, but conclude either before the
end of the event offset, at the end of the event offset, or after the end of the event offset.
[00611 FIG. 5 shows example techniques for downlink event offset allocation 500. In the
example, a period 502 (e.g., a period of time) is configured to include a plurality of event offsets
504-522. The downlink event offset allocation 500 differs from the allocation 400 primarily in
that it includes more event offsets. The length of the period of time 402 and may be shorter than, the same as, or longer than, the period of time 502. Similarly, the length of the event offsets
404-414 and may be shorter than, the same as, or longer than, the length of event offsets 504
522. Additionally, each of the event offsets 404-414 may be of the same duration or different
durations. Similarly, each of the event offsets 504-522 may be of the same duration or different
durations.
[00621 FIG. 6 illustrates an example listening event offset 600 in which a BPD may listen for messages that are transmitted by other devices, such as MPDs. By listening for messages only
at scheduled listening event offsets according to a repeating schedule, the BPD may minimize
the amount of battery power that would otherwise be utilized in order to listen for messages at
all times. The listening event offset repeating schedule is typically shared, learned and/or
negotiated with other devices that may be sending messages to the BPD. This sharing, learning
and/or negotiating may occur, for example, in a discovery period during which the BPD is
discovering other devices that are already joined to a network, or over time via the use of beacons
and/or other communications not specifically for discovery. Discovery may be, for example,
via passive discovery beacons that are broadcast by the already-joined devices. As mentioned
above, this listening methodology for a BPD to listen for messages from other network devices
may conserve battery life as compared to methodologies in which the BPD has its receiver on
for long periods. Generally, actively receiving uses less power than transmitting. Furthermore,
passively listening generally uses less power than actively receiving.
[00631 At FIG. 6, the listening event offset 600 is associated with an offset at which a BPD is
listening for a message 602 from another device. The message 602 typically comprises a packet
preamble and frame synchronization delimiter (PA/SFD) 604 and a packet payload 606. Due to
an uncertainty by the BPD as to when the other device will transmit the message, the listening
event offset 600 also includes a timing uncertainty window before (608A) and after (608B) the
message 602. The timing uncertainty windows 608A and 608B generally accounts for a mis
synchronization of device clocks as well as accounting for a jitter in the transmission of the
message 602. Jitter may include, for example, an uncertainty in a transmitter on time due to characteristics of a transmitter possibly as well an uncertainty in the clock used by the transmitter to time its transmissions.
[00641 Particularly given the listening event offset schedules of multiple BPDs, a device sending messages to those BPDs would conventionally implement a methodology to store and
then transmit messages to the BPDs at the listening event offsets. The messages being
transmitted to the BPDs by a device may, for example, include data of iPv6 packets received by
the device, such as via an edge router of a network. In another example, the packets being
transmitted to the BPDs by a device may include messages from a security module, such a
security module implementing Extensible Authentication Protocol (EAP) over LAN (EAPoL),
which is a network port authentication protocol used in IEEE 802.1X (Port Based Network
Access Control) developed to give a generic network sign-on to access network resources.
[00651 FIG. 7 shows an example schedule 116 of event start-time offsets and/or timeslots that may be used to time and/or coordinate communications between a mains-powered device (e.g.,
device 102 of FIG. 1) and one or more battery-powered devices (e.g., devices 104 of FIG. 1).
All or part of the schedule 116 may be used on one or more of the service providers 112, the
edge device 108, the mains-powered device 102 and/or the battery-powered device 104.
[00661 In the example, the schedule 116 includes a plurality of event timeslots (with representative timeslots 702-708 being labeled). Each timeslot is associated with a respective
event start-time offset 710-716. In the example, the timeslots are of uniform duration, i.e., uniform spacing in time. In the example, the schedule governs operation of two groups of
devices distinguished by their different sleep/wake cycles. A first group of devices 718 has a
sleep/wake cycle 720, 722. A second group of devices 724 has a sleep/wake cycle 726. In the
example, two sleep/wake cycles (or activity cycles, etc.) 720, 722 of the first group of devices
718 are completed during the single sleep/wake cycle 726 of the second group of devices 724.
[00671 In other examples, groups of devices having different ratios of sleep/wake cycles could
be used. For example, if a first group of devices had a sleep/wake cycle of 7 minutes and a
second group of devices had a sleep/wake cycle of 11 minutes, a schedule of 77 minutes could
be created in which 11 cycles of the first group and 7 cycles of the second group were used to create the schedule. Regardless of length, the schedule may be repeated upon completion, such as for days, months and/or years.
[00681 In an example, the sleep/wake period of a device may include a period of time wherein the device "sleeps" (e.g., lower power consumption and radio off), and a period of time wherein
the device is "awake" (e.g., higher power consumption and radio on). In some examples, the
sleep period is longer than the wake period. For example, the device may sleep for 4 minutes
and 59 seconds and be awake for 1 seconds. Numerous other sleep and wake periods are
possible and envisioned.
[00691 Zero or more devices from among the first group of devices 718 are associated with each timeslot. In an example, a plurality of devices 728 (e.g., 100 battery-powered devices)
from among the first group of devices 718 (having a first sleep/wake cycle duration) may be
associated a first timeslot 702 following the first event start-time offset 710. Additionally, a
plurality of devices 730 from among the second group of devices 724 (having a second
sleep/wake cycle duration) may also be associated the first timeslot 702 following the first event
start-time offset 710.
[00701 In example operation, a mains-powered device may perform a broadcast or multicast transmission during a timeslot. In an example, the mains-powered device may perform a
broadcast to the groups of devices 728, 730 in the timeslot 702. In the broadcast, all the devices
728, 730 would wake and tune an appropriate frequency and would receive data during the
timeslot 702 that starts at the event start-time offset 710. In examples, some or all the devices
718, 724 may be included in the groups 728, 730.
[00711 In examples, some or all the devices 718, 724 may be included in two or more groups. This allows a device to receive a broadcast (e.g., if the device is a member of group 728 or 730)
and a unicast (e.g., if the device is a member of another group from among 732-760).
Membership in a group may be defined by a schedule, which associates devices with timeslots,
RF frequencies, and/or modulation schemes, etc.
[00721 In examples, the devices 718 and 724 may be associated with one or more unicast timeslots (e.g., timeslots 704, 706 through 708, etc.). During a unicast timeslot, one or more devices assigned to that timeslot wakes up, tunes a frequency, decodes packet(s) and determines if its identification or identifier has been transmitted. If so, the device continues to decode packets, respond to commands, send packets, etc. If not, the device may return to a sleep mode.
100731 Each timeslot 704, 706 through 708, etc., may have a plurality of devices associated with it in a schedule. In a typical network environment, there are more devices than timeslots.
Accordingly, in timeslots associated with unicast transmissions, a plurality of devices will wake,
tune, decode and determine if a message is intended for them.
100741 In a schedule, one or more timeslots may be associated with a broadcast (e.g., timeslot 702), while other timeslots may be associated with unicasts (e.g., timeslots 704 through 708).
The timeslots utilized for unicast transmissions may be associated with a number of devices. In
the example of FIG. 7, timeslot 704 is associated with the group of devices 732 and group of
devices 750. The two groups of devices have different sleep/wake periods, but each device from
the two groups wakes and uses the timeslot 704. A distribution of the numbers of devices
associated with each timeslot utilized for unicast transmissions may be substantially uniform.
That is, a similar number of devices is associated with each timeslot. This helps to "smooth"
the RF traffic in the network by having each device share a timeslot with similar numbers of
other devices.
100751 In an example, a schedule governing aspects of network operation may include dedicated unicast timeslots 762, 764 that may be used for unicast transmissions associated with
the first group 718 of devices having a first wakeup/sleep cycle. Unicast timeslots 766, 768 may
be used for unicast transmissions associated with the second group 724 of devices having a
second wakeup/sleep cycle. Each timeslot in the groups of timeslots 762, 764, 766, 768 is
associated with a number of devices in the network that is substantially similar to other timeslots
in the groups. Accordingly, a distribution of network devices associated with each timeslot
within groups 762, 764, 766, 768 of dedicated unicast timeslots is substantially uniform. And a
such a distribution of devices associated with the timeslots, that is, numbers of devices associated
with each timeslot, may be made in a manner such that a variance of the distribution is held
below a threshold value. In an example, the number of devices associated with each timeslot may be allowed to differ by only "n" devices, wherein "n" devices. The "n" devices may be a fraction of the average number of devices associated with each timeslot. In an example, 80 to
85 devices may be associated with each timeslot. Other examples may be different, but the
variance of the distribution of numbers of devices associated with each timeslot may be held
under a desired threshold.
[00761 In an example, the threshold value may be selected as a compromise between the need to move devices to alternative timeslots and the need to prevent some devices from being
assigned to an overly large group of devices that shares a timeslot.
Example Methods
[00771 In some examples of the techniques discusses herein, the methods of operation may be performed by one or more application specific integrated circuits (ASIC) or may be performed
by a general-purpose processor 202 utilizing software defined in computer readable media. In
the examples and techniques discussed herein, the memory 212 may comprise computer
readable media and may take the form of volatile memory, such as random-access memory
(RAM) and/or non-volatile memory, such as read only memory (ROM) or flash RAM.
Computer-readable media devices include volatile and non-volatile, removable and non
removable media implemented in any method or technology for storage of information such as
computer-readable instructions, data structures, program modules, or other data for execution
by one or more processors of a computing device. Examples of computer-readable media
include, but are not limited to, phase change memory (PRAM), static random-access memory
(SRAM), dynamic random-access memory (DRAM), other types of random access memory
(RAM), read-only memory (ROM), electrically erasable programmable read-only memory
(EEPROM), flash memory or other memory technology, compact disk read-only memory (CD
ROM), digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape,
magnetic disk storage or other magnetic storage devices, or any other non-transitory medium
that can be used to store information for access by a computing device.
[00781 As defined herein, computer-readable media does not include transitory media, such as modulated data signals and carrier waves, and/or signals.
[00791 FIGS. 8 through 13 are flow diagrams showing an example processes which are representative of techniques for use in downlink event offset allocation. The processes may, but
need not necessarily, be implemented in whole or in part by the mains-powered device 200
and/or the battery-powered device 300, within a network (e.g., network 100).
[00801 FIG. 8 shows example techniques 800 by which multicast transmission(s) may be sent according to timing based at least in part on one or more event offsets. In some example
implementations, battery-powered devices may be organized into one or more groups. The
groups may be based on a technology used by the battery-powered devices, such as an RF
frequency used, a modulation scheme used, a functionality of the battery-powered devices (e.g.,
gas meters, water meters, etc.), and/or other factors.
[00811 In an example, the groups maybe based at least in part on awakeup cycle of the battery powered devices. A mains-powered device may send multicast and/or broadcast transmissions
to one or more groups of battery-powered devices based at least in part on timing indicated by a
respective one or more event offsets.
[00821 In a first example, the mains-powered device may send a broadcast transmission using a first timeslot following a first event offset including information of interest to water meters
having a first wakeup cycle time, which may be configured to use a first RF modulation scheme
and frequency. In a second example, the mains-powered device may send a broadcast
transmission using a second timeslot following a second event offset including information of
interest to gas meters having a second wakeup cycle time, which may be configured to use a
same or different RF modulation scheme and frequency. In a third example, the mains-powered
device may send unicast messages during each of a plurality of dedicated unicast timeslots. The
network devices may be assigned to dedicated unicast timeslots in a substantially uniform
manner, and a variance of a distribution of numbers of devices assigned to timeslots may be held
under a desired threshold by avoiding assignment of too many or too few devices to each
timeslot.
[0083] In the example of block 802, a device transmits (e.g., according to a schedule) a broadcast transmission to a plurality of devices at a first time indicated by a first event start-time
offset from among a plurality of event start-time offsets indicated by the schedule. In the
example of block 804, the devices transmitting and/or receiving data according to the schedule
may be a mains-powered device (MPD) and/or a battery-powered device. In some example, a
mains-powered device may send software updates, scheduling information, commands, and/or
other data to battery-powered devices. Battery-powered devices may send metering data or
other information to the mains-powered device.
[0084] In the example of block 806, a first unicast transmission may be transmitted to a device from among the plurality of devices at times, channels, etc. indicated by the schedule. In the
example, the transmission may be made at a second time indicated by a second event start-time
offset from among the plurality of event start-time offsets indicated by the schedule. In the
example of block 808, the devices of the plurality of devices are battery-powered devices
(BPDs).
[0085] In the example of block 810, a plurality of transmissions (e.g., unicast transmissions)
may be transmitted to the plurality of devices (e.g., battery-powered devices). In the example,
the transmitting may be performed according to the schedule. In the example, the plurality of
devices with the plurality of event start-time offsets (or plurality of timeslots) are associated in
the schedule such that a distribution of numbers of devices associated with each of the plurality
of event start-time offsets dedicated to unicast transmissions is substantially uniform.
[0086] Thus, each timeslot in the schedule is used by, and/or is associate with, approximately the same number of devices as any other timeslot. The difference in the number of devices
associated with each timeslot of the plurality of timeslots may be constrained to be within a
threshold value (in absolute terms or as a percentage) of the number of devices associated with
any other timeslot in the schedule. Alternatively, the variance of the number of devices attached
to each timeslot of the plurality of timeslots in the schedule may be required to be below a
threshold value. Other means may be used as desired to measure and/or enforce the uniformity
of the number of devices associated with each timeslot following each event start-time offset.
[00871 In the example of block 812, a second unicast transmission may be sent to a second
device at a time indicated by an event start-time offset (or appropriate timeslot). A radio
frequency of the second unicast transmission may be based at least in part on a media access
control (MAC) address of the third device.
[00881 FIG. 9 shows example techniques 900 by which a duration of timeslots is determined,
i.e., a spacing of event start-time offsets is determined. Additionally, FIG. 9 shows an example
by which devices (e.g., battery-powered devices) are assigned to timeslots, during which that
can tune in and determine if a message is directed to them. Three example techniques are
presented, which measure and/or enforce the substantial uniformity of the number of devices
associated with each of the plurality of timeslots.
[00891 At the example of block 902, a number of event start-time offsets (i.e., timeslots) may
be determined. The timeslots will segment a sleep/wake cycle of a battery-powered device type.
The number of timeslots may be based on one or more factors, including a number of battery
powered devices expected to communicate with a mains-powered device, expected message
lengths in the communications, an expected data rate, and/or other factors according to an
application in a network.
[00901 At block 904, devices are assigned to the timeslots within the sleep/wake cycle of the
timeslots as determined at block 902. In the example of block 906, a number of devices is
assigned to each timeslot (e.g., dedicated unicast timeslot, used only for unicast transmissions)
so that a variance of the numbers of devices assigned to timeslots is less than a threshold value.
[00911 Alternatively or additionally, at block 908 a number of devices is assigned to each
timeslot (e.g., dedicated unicast timeslot) so that a number of devices (either in absolute terms
or expressed as a percentage) is less than a threshold value. In examples, no timeslot would
have more than a threshold number of devices more or less than any other timeslot, or no timeslot
would have a number of devices that is more or less than another timeslot by a threshold
percentage.
[00921 In the example of block 910, devices are assigned to timeslot (e.g., dedicated unicast timeslot) to that each timeslot has either "N" devices or "N+1" devices, wherein "N" is an integer
that is zero or greater.
[00931 FIG. 10 shows example techniques 1000 by which a device may be joined to a network. At block 1002, a request is received from a device to join a network, which may include one or
more mains-powered and battery-powered devices. At block 1004, the device is installed in the
network and is associated with an event start-time offset (e.g., a unicast dedicated timeslot) in a
manner such that a number of devices assigned to each timeslot is distributed in a substantially
uniform manner over the period of the schedule (which may be equal to the sleep/wake cycle of
the battery-powered devices in the network).
[00941 FIG. 11 shows example techniques 1100 by which a device may be removed from the network. At block 1102, the mains-powered device (or another network device) detects that a
first device (e.g., a battery-powered device) has left the network. In an example, the battery
powered device reported to the mains-powered device that it was leaving the network. At block
1104, an event start-time offset or timeslot of a second device that is not leaving the network is
changed to the timeslot of the device that is left the network. Accordingly, the number of devices
associated with the timeslots of the period of the schedule may be altered to increase their
uniformity (i.e., to decrease their variance).
[00951 FIG. 12 shows example techniques 1200 by which a mains-powered device may communicate with a battery-powered device. In some instances, communication may require
more time than is in the timeslot. In some instances, the timeslot is approximately the period of
time needed for a packet preamble to be transmitted. Insuchinstances,themains-powered
device and the battery-powered device may communicate for a period that is longer than the
timeslot. Other battery-powered devices, waking for their own timeslots, will hear data and not
a preamble and/or their ID number. Accordingly, they will not communicate with the mains
powered device until a different iteration of the schedule.
[00961 At block 1202, a mains-powered device and a battery-powered device transmit and/or receive data according to a schedule. At block 1204, a preamble of a packet of a first unicast transmission is transmitted during a first timeslot. Devices associated with the timeslot and that begin to decode at the timeslot will recognize the preamble and continue to decode. The packet may include an identification of the device to whom the packet and/or subsequent packets are directed.
[00971 At block 1206, other portions of the packet (e.g., data) or subsequently transmitted
packets, are transmitted during subsequent timeslots. Other devices that begin to decode at these
time(s) will not recognize a preamble and start frame synchronization delimiter (PA/SFD) and
will not recognize their device identification. Such devices, realizing that packets are not
directed to them, may resume a sleep portion of their respective activity cycles.
[00981 FIG. 13 shows techniques 1300 for communication between a mains-powered device
and one or more battery-powered devices. At block 1302, a transmission (e.g., from a mains
powered device to a battery-powered device) is performed according to a schedule (e.g.,
schedule 116 seen in FIGS. I and 7).
[00991 At block 1304, a mains-powered device transmits (and a plurality of battery-powered
devices receive), according to the schedule, a multicast transmission to at least two battery
powered devices. In an example, the multicast transmission is sent at a time indicated by an
event start-time offset (or timeslot following the offset) from among the plurality of event start
time offsets (or timeslots) in the schedule.
[01001 At block 1306, a first battery-powered device from among a plurality of devices
communicates (e.g., transmits data to and/or receives data from) the mains-powered device)
according to a first event start-time offset of the schedule. The transmission is made during a
high-power-use period of the battery-powered device. At block 1308, a second battery-powered
device from among the plurality of devices transmits and/or receives according to a second event
start-time offset of the schedule during a low-power-use period of thefirst battery-powered
device.
[01011 FIG. 14 shows example techniques 1400 whereby a plurality of battery-powered
devices (BPD) are configured use a schedule to share timeslots and/or spectrum. In the example,
a number of devices are associated with timeslots (e.g., timeslots dedicated for use only in unicast transmissions) in a substantially uniform manner. Thus, a substantially similar number of battery-powered devices are associated with each timeslot. Similarly, a variance of the number of devices associated with each timeslot is less than a threshold value.
[0102] At block 1402, a broadcast transmission is received at each of two or more devices
according to a first event start-time offset indicated by a schedule. At block 1404, each of the
two or more devices is associated in the schedule with an event start-time offset (e.g., a timeslot
dedicated for unicast transmissions) such that a distribution of numbers of devices associated
with each of two or more event start-time offsets is substantially uniform.
[0103] At block 1406, data is received and/or sent at a first device from among the two or more
devices according to a second event start-time offset indicated by the schedule.
[0104] At block 1408, data is received and/or sent at a second device from among the two or
more devices according to a second event start-time offset indicated by the schedule.
[0105] At block 1410, the schedule may be changed to move at least one of the two or more
devices from a first event start-time offset to a second event start-time offset. The move may
reduce variance in the number of devices associated with each timeslot.
[0106] FIG. 15 shows example techniques 1500 whereby a mains-powered device adds node(s)
to a network. As a new battery-powered device is connected to the network, it is assigned to an
event start-time offset and/or timeslot. At the timeslot, the mains-powered device communicates
with the new device. In the example, at blocks 1502 through 1508, a battery-powered device
requests to be added to the network, receives a selected timeslot, and communicates on that
timeslot. In the example, at blocks 1510 through 1512, a second device is added to the network.
If the network contains more devices than timeslots, then a timeslot is assigned, even though it
is already assigned to another device. In the example of blocks 1514 through 1516, a device
may leave the network and its timeslot may be reassigned to another device. In some examples,
each time a timeslot is assigned (or reassigned) the assignment may be made in a manner that
keeps a variance of a distribution of numbers of devices assigned to timeslots less than a
threshold value.
[0107] At block 1502, a request is received to add a device (e.g., a battery-powered device) to a network. The request may come from the battery-powered device itself, of from a network
manager, edge device, etc.
[0108] At block 1504, an event start-time offset is selected for assignment to the device. Event start-time offsets may be selected in a manner that maintains the variance of the distribution of
devices assigned to offsets less than a target threshold.
[0109] At block 1506, the battery-powered device is instructed to transmit and/or receive data according to a schedule. The schedule may indicate the selected event start-time offset or
associated timeslot.
[0110] At block 1508, a unicast message may be sent to the battery-powered device at a time
indicated by the schedule.
[0111] At block 1510, a second request is received to add a second device to the network.
[0112] At block 1512, the event start-time offset, already assigned to the first device, may be selected for assignment to the second device. Accordingly, more than one device may be
associated with a timeslot. This allows for more device than there are timeslots to be added to
the network.
[0113] At block 1514, it may be determined that the first device has left the network. Devices may be added or removed from the network, responsive to changes in customers' locations,
numbers, etc.
[0114] At block 1516, the selected event start-time offset (e.g., selected at block 1512) may be
reassigned to a third device that is part of the network.
[0115] FIG. 16 is a flow diagram showing example techniques 1600 for building a schedule of event start-time offsets indicating timeslots consistent with two groups of battery-powered
devices with different sleep/wake cycle lengths. The techniques 1600 may be utilized by a
mains-powered device or other network device.
[0116] At block 1602, a first set of devices that have a first wakeup rate are allocated to event start-time offsets based at least in part on the first wakeup rate.
[0117] At block 1604, a second set of devices that have a second wakeup rate are allocated to event start-time offsets based at least in part on the second wakeup rate. In an example, the first
and second sets of devices are battery-powered devices.
[0118] At block 1606, a schedule is generated based at least in part on the allocation of the first set of devices and the allocation of the second set of devices.
[0119] At block 1608, a mains-powered device transmits according to the schedule to a first device among a first plurality of battery-powered devices allocated to a first event start-time
offset.
[0120] At block 1610, the mains-powered device transmits according to the schedule to a second device among a second plurality of devices allocated to a second event start-time offset.
[0121] FIG. 17 is a flow diagram showing four example techniques 1700 for allocating devices to particular event start-time offsets (i.e., timeslots). At block 1702, a device (e.g., a mains
powered device, server in a remote location, etc.) allocates devices to event start-time offsets,
thereby associating battery-powered devices to timeslots for communication.
[0122] Block 1704 shows a first example allocation, wherein a substantially uniform number
of devices are allocated to a plurality of event start-time offsets. Thus, a distribution of the
numbers of devices associated with each of a plurality of timeslots is substantially uniform.
[0123] Block 1706 shows a second example allocation, wherein numbers of devices are allocated to each a plurality of event start-time offsets so that a distribution of the numbers has
a variance that is less than a threshold value.
[0124] Block 1708 shows a third example allocation, wherein devices are allocated to event start-time offsets within the schedule such that event start-time offsets are associated with "n"
number of devices or "n" plus 1 number of devices, wherein "n" is an integer that is zero or
greater. Such an allocation prevents some timeslots from being associated with significantly
more devices than other timeslots.
[0125] Block 1710 shows a fourth example allocation, wherein 1710 the first set of devices and the second set of devices are allocated to event start-time offsets having uniform spacing in
time. That is, each event start-time offset may indicate the beginning of a timeslot, and the timeslots are of uniform duration. Accordingly, battery-powered devices having longer or shorter sleep/wake periods are all associated with timeslots of uniform duration.
[01261 FIG. 18 is a block diagram showing example techniques 1800 for removing devices
from a network, and responsive to the removal, changing an event start-time offset of a different
device to maintain the substantial uniformity of the distribution of devices over the offsets. In
an example, the schedule may be changed to move one of the two or more devices from a first
event start-time offset to a second event start-time offset. In the example, the changing of the
schedule is performed in a manner that reduces a variance of the distribution of numbers of
devices associated with each of a plurality of event start-time offsets.
[01271 At block 1802, it is determined that a first device from among a first set of devices has
left or will leave a network including the first set of devices. At block 1804, an event start-time
offset of a second device from among the first set of devices that is not leaving the network is
changed to an event start-time offset previously used by the first device. Accordingly, when a
device leaves a network, it may be advantageous to have a different device, still on the network,
move from its timeslot to the timeslot of the departing device. Such a move may result in less
variance in a distribution of numbers of devices associated with timeslots in a schedule. This
results in better use of available radio frequency spectrum.
[01281 FIG. 19 is a block diagram showing example techniques 1900 for adding a device to a
network. At block 1902, a request is received from a device to join a network of the first set of
devices. At block 1904, the device may be assigned to an event start-time offset such that a
distribution of numbers of devices assigned to each event start-time offset is substantially
uniform.
[01291 FIG. 20 shows example techniques 2000 for constructing a schedule used
communication with two or more groups of battery-powered devices (BPDs), each group having
activity cycles of different lengths of wake (higher-power use) and sleep (lower-power use)
periods.
[01301 At block 2002, each device of a first set of devices has a first wakeup rate and/or activity
cycle. The devices of the first set of devices are allocated to event start-time offsets (e.g., timeslots) occurring over a first period of time. In an example, the first period of time is based at least in part on the first wakeup rate. In examples, the first period of time may be equal to an activity cycle including an active phase and a sleep phase. The allocation may be performed such that a distribution of the first set of devices over the event start-time offsets occurring over the first period of time is substantially uniform. That is, a substantially uniform numbers of devices are assigned to each timeslot. Thus, some timeslots do not have significantly more or less assigned devices. This tends to more efficiently use radio frequency spectrum.
[01311 In an example where one or more of the timeslots is associated with a broadcast or multicast event associated with a large number of network devices, the other timeslots would be
associated with network devices in a substantially uniform manner. Thus, dedicated unicast
timeslots would be configured with substantially the same number of devices assigned to each
such timeslot. In an example, a variance of a distribution of the numbers of devices associated
with timeslots would be held under a threshold value, such as by assigning devices to timeslots
so that the number of devices assigned to each timeslot was approximately the same. As seen
in the example of FIG. 7, each of the dedicated unicast timeslots 762, 764 are assigned
approximately the same number of devices, and the distribution of devices is substantially
uniform over the timeslots.
[01321 At block 2004, each device of a second set of devices has a second wakeup rate and/or activity cycle, different from the first activity cycle. The devices of the second set of devices are
allocated to event start-time offsets occurring over a second period of time. The allocation is
performed in a manner similar to that of the allocation of block 2002.
[01331 At block 2006, a schedule is generated based at least in part on the allocation of the first set of devices and the allocation of the second set of devices. In an example operation, network
devices may repeatedly use the schedule to time and direct (e.g., RF frequency, modulation
scheme, etc.). In an example, if the schedule governs fifteen minutes of communication, it may
be repeated four times an hour and 96 times a day.
[01341 In an example, the schedule is generated such that a distribution of the first set of devices and the second set of devices within dedicated unicast timeslots of the schedule is substantially uniform over the duration of the schedule. The schedule may be generated by combining two or more schedules associated with respective two or more groups of devices, each group of devices associated with a particular sleep/wake cycle. Each of the component schedules may be created so that a distribution of numbers of devices associated with dedicated unicast timeslots is substantially uniform. Combining two or more such component schedules, having timeslots of equal duration and temporal alignment, would yield a combined schedule having similar substantial uniformity.
[01351 The duration of the schedule may be a whole number multiple of both of the activity
cycles of the two sets of devices. In an example, if first set of devices has an activity cycle of 2
minutes (including both sleep and wake portions) and the second set of devices has an activity
cycle of 3 minutes, the schedule may have a duration of 6 minutes to include three cycles of the
devices of the first set and two cycles of devices of the second set. Referring to the example of
FIG. 7, two activity cycles 720, 722 of a first group of devices and one activity cycle 726 of a
second group of devices 724 are used to form the schedule 116.
[01361 The schedule does not have to be limited to cover a particular length of time.
Alternatively, the schedule may be generated in real time, as it is used.
Examples
[01371 The following numbered clauses are example embodiments.
[01381 1. A method, comprising: transmitting, according to a schedule, a broadcast
transmission to a plurality of devices at a first event start-time offset from among a plurality of
event start-time offsets indicated by the schedule; transmitting, according to the schedule, a first
unicast transmission to a device from among the plurality of devices at a second time indicated
by a second event start-time offset from among the plurality of event start-time offsets indicated
by the schedule; and transmitting a plurality of unicast transmissions to the plurality of devices,
wherein the transmitting is performed according to the schedule, and wherein a distribution of
numbers of devices associated with event start-time offsets dedicated to unicast transmissions is
substantially uniform.
[0139] 2. The method of clause 1, additionally comprising: assigning devices to event start time offsets such that a variance of the distribution of numbers of devices associated with each
of the plurality of event start-time offsets is under a threshold value.
[0140] 3. The method of clause 1, additionally comprising: assigning devices to event start time offsets within the schedule such that a difference between a number of devices assigned to
a third event start-time offset and a number of devices assigned to a fourth event start-time offset
is within a threshold value.
[0141] 4. The method of clause 1, additionally comprising: assigning devices to event start time offsets within the schedule in a manner that results in each event start-time offset being
associated with "n"number of devices or "n" plus 1 number of devices, wherein "n" is an integer
that is zero or greater.
[0142] 5. The method of clause 1, wherein a number of event start-time offsets defined within the schedule is based at least in part on one or more factors, comprising: a number of battery
powered devices expected to communicate with a mains-power device; an expected message
length used in communications between the battery-powered devices and the mains-powered
device; an expected data rate used by the battery-powered devices and the mains-powered
device.
[0143] 6. The method of clause 1, additionally comprising: transmitting, according to the schedule, a multicast transmission to at least two devices, wherein the multicast transmission is
sent at a third time indicated by a third event start-time offset from among the plurality of event
start-time offsets.
[0144] 7. The method of clause 1, additionally comprising: detecting that a first device from among the plurality of devices has left a network including the plurality of devices; and changing
an event start-time offset of a second device from among the plurality of devices that is not
leaving the network to an event start-time offset previously used by the first device.
[0145] 8. The method of clause 1, additionally comprising: receiving a request from a device tojoin a network of the plurality of devices; and assigning the device to an event start-time offset
such that a number of devices assigned to each event start-time offset is substantially uniform.
[0146] 9. The method of clause 1, additionally comprising: receiving requests from additional devices to join a network; assigning the additional devices to event start-time offsets
within the schedule in a manner that results in each event start-time offset being associated with "n" number of devices or"n" plus I number of devices, wherein"n" is an integer that is zero or
greater.
[0147] 10. The method of clause 1, wherein: a device transmitting according to the schedule is a mains-powered device (MPD); and devices of the plurality of devices are battery-powered
devices (BPDs).
[0148] 11. The method of clause 1, additionally comprising: transmitting a preamble of a packet of the first unicast transmission at the first event start-time offset associated with a first
battery-powered device; and transmitting portions of the packet other than the preamble of the
packet after the second event start-time offset associated with a second battery-powered device.
[0149] 12. The method of clause 1, additionally comprising: sending a second unicast transmission to a second device at a time indicated by a third event start-time offset; wherein a
radio frequency of the second unicast transmission is based at least in part on a media access
control (MAC) address of the third device.
[0150] 13. The method of clause 1, additionally comprising: transmitting to a first battery powered device from among the plurality of devices according to a first event start-time offset
of the schedule during a high-power-use period of the first battery-powered device; and
transmitting to a second battery-powered device from among the plurality of devices according
to a second event start-time offset of the schedule during a low-power-use period of the first
battery-powered device.
[0151] 14. A method, comprising: receiving a broadcast transmission at each of two or more devices according to a first event start-time offset indicated by a schedule; receiving data in a
first unicast transmission at a first device from among the two or more devices according to a
second event start-time offset indicated by the schedule; and receiving data in a second unicast
transmission at a second device from among the two or more devices according to a third event start-time offset indicated by the schedule; wherein the schedule associates numbers of devices to event start-time offsets dedicated to unicast transmissions in a substantially uniform manner.
[01521 15. The method of clause 14, wherein: a battery-powered device from among the two
or more devices communicates according to an event start-time offset of the schedule during a
high-power-use period of the battery-powered device; and the battery-powered device alternates
high-power-use periods and low-power-use periods according event start-time offsets.
[01531 16. The method of clause 14, wherein: at least two battery-powered devices, from
among the two or more devices, are associated with a same event start-time offset within the
schedule; and at the same event start-time offset, each of the at least two battery-powered devices
determine if a message is available.
[01541 17. The method of clause 14, additionally comprising: changing the schedule to move
one of the two or more devices from a first event start-time offset to a second event start-time
offset; wherein the changing of the schedule reduces a variance of the distribution of numbers
of devices associated with each of a plurality of event start-time offsets.
[01551 18. A method, comprising: receiving a request to add a device to a network; selecting
an event start-time offset for assignment to the device, wherein the selected event start-time
offset is selected such that such that a distribution of numbers of devices associated with each of
a plurality of event start-time offsets is substantially uniform; instructing the device to transmit
and/or receive data according to a schedule based at least in part on the selected event start-time
offset, wherein the schedule associates numbers of devices on the network to event start-time
offsets dedicated to unicast transmissions in a substantially uniform manner; and sending a
unicast message to the device at a time indicated by the schedule.
[01561 19. The method of clause 18, wherein the device is a first device, the method
additionally comprising: receiving a second request to add a second device to the network; and
selecting the event start-time offset, already assigned to the first device for assignment to the
second device.
[01571 20. The method of clause 18, wherein the device is a first device, and the method
additionally comprises: determining that the first device has left the network; and reassigning the selected event start-time offset to a second device that is part of the network; wherein the reassigning is performed such that the distribution of numbers of devices associated with each of the plurality of event start-time offsets used by devices connected to the network has a variance that is less than a threshold value.
[0158] 1. A method, comprising: allocating a first set of devices each having a first wakeup rate to event start-time offsets occurring over a first period of time, wherein the first period of
time is based at least in part on the first wakeup rate, and wherein the allocating is performed
such that a distribution of the first set of devices over the event start-time offsets occurring over
the first period of time and dedicated to unicast transmissions is substantially uniform; allocating
a second set of devices each having a second wakeup rate to event start-time offsets occurring
over a second period of time, wherein the second period of time is based at least in part on the
second wakeup rate, and wherein the allocating is performed such that a distribution of the
second set of devices over the event start-time offsets occurring over the second period time and
dedicated to unicast transmissions is substantially uniform; generating a schedule based at least
in part on the allocation of the first set of devices and the allocation of the second set of devices.
[0159] 2. The method of clause 1, wherein the generating comprises: generating the schedule such that a distribution of the first set of devices and the second set of devices over event start
time offsets dedicated to unicast transmissions within the schedule is substantially uniform.
[0160] 3. The method of clause 1, wherein allocating the sets of devices comprises: allocating numbers of devices to each of a plurality of event start-time offsets dedicated to unicast
transmission so that a distribution of the numbers has a variance that is less than a threshold
value.
[0161] 4. The method of clause 1, wherein allocating the sets of devices comprises: allocating devices to event start-time offsets dedicated to unicast transmissions within the schedule such
that event start-time offsets are associated with "n" number of devices or "n" plus I number of
devices, wherein "n" is an integer that is zero or greater.
[01621 5. The method of clause 1, wherein allocating the sets of devices comprises: allocating
the first set of devices and the second set of devices to event start-time offsets, wherein the event
start-time offsets have the same uniform spacing in time.
[01631 6. The method of clause 1, additionally comprising: transmitting, according to the
schedule, to a first device among a first plurality of devices allocated to a first event start-time
offset; and transmitting, according to the schedule, to a second device among a second plurality
of devices allocated to a second event start-time offset.
[01641 7. The method of clause 1, additionally comprising: determining that a first device
from among the first set of devices has left a network including the first set of devices; and
changing an event start-time offset of a second device from among the first set of devices that is
not leaving the network to an event start-time offset previously used by the first device.
[01651 8. The method of clause 1, additionally comprising: receiving a request from a device
tojoin a network of the first set of devices; and assigning the device to an event start-time offset
such that the distribution of the first set of devices over the event start-time offsets occurring
over the first period of time is substantially uniform.
[01661 9. The method of clause 1, additionally comprising: transmitting according to the
schedule is by operation of a mains-powered device; wherein the first set of devices and the
second set of devices are battery-powered devices.
[01671 10. A method, comprising: allocating a first set of devices each having a first
sleep/wake period to event start-time offsets occurring over a first period of time, wherein the
first period of time is based at least in part on the first sleep/wake period; allocating a second set
of devices each having a second sleep/wake period to event start-time offsets occuming over a
second period of time, wherein the second period of time is based at least in part on the second
sleep/wake period; and generating a schedule based at least in part on the allocation of the first
set of devices and the allocation of the second set of devices, wherein the generating configures
the schedule such that a distribution of devices allocated to event start-time offsets dedicated to
unicast transmissions, comprising the first set of devices and the second set of devices, is
substantially uniform.
[0168] 11. The method of clause 10, wherein: allocating the first set of devices comprises performing the allocation such that a distribution of the first set of devices over the event start
time offsets dedicated to unicast transmissions occurring over the first period of time is
substantially uniform; and allocating the second set of devices comprises performing the
allocation such that a distribution of the second set of devices over the event start-time offsets
dedicated to unicast transmissions occurring over the second period of time is substantially
uniform.
[0169] 12. The method of clause 10, additionally comprising: sending a message to a device from among a plurality of devices associated with a same event start-time offset, wherein the
message comprises an identification of the device.
[0170] 13. The method of clause 10, additionally comprising: transmitting to devices according to the schedule; and repeating the transmitting after transmitting for a duration of the
schedule.
[0171] 14. The method of clause 10, wherein generating the schedule comprises: generating the schedule to be of length that is a whole number multiple of a duration of thefirst sleep/wake
period and to be a whole number multiple of a duration of the second sleep/wake period.
[0172] 15. The method of clause 10, additionally comprising: transmitting, according to the schedule, to a first device among a first plurality of devices allocated to a first event start-time
offset; and transmitting, according to the schedule, to a second device among a second plurality
of devices allocated to a second event start-time offset.
[0173] 16. The method of clause 10, additionally comprising: determining that a first device from among the first set of devices has left a network including the first set of devices; and
changing an event start-time offset of a second device from among the first set of devices that is
not leaving the network to an event start-time offset previously used by the first device.
[0174] 17. The method of clause 10, additionally comprising: receiving a request from a
device to join a network of the first set of devices; and assigning the device to an event start
time offset such that a distribution of a number of devices assigned to each event start-time offset
occurring over the first period of time is substantially uniform.
[01751 18. The method of clause 10, additionally comprising: transmitting according to the schedule is by operation of a mains-powered device; wherein the first set of devices and the
second set of devices are battery-powered devices.
[01761 19. A method, comprising: allocating a first set of devices each having a first sleep/wake period to event start-time offsets dedicated to unicast transmissions occurring over a
first period of time, wherein the first period of time is based at least in part on the first sleep/wake
period; allocating a second set of devices each having a second sleep/wake period to event start
time offsets dedicated to unicast transmissions occurring over a second period of time, wherein
the second period of time is based at least in part on the second sleep/wake period; and generating
a schedule based at least in part on the allocation of the first set of devices and the allocation of
the second set of devices, wherein the schedule is a length that is a whole number multiple of a
duration of the first sleep/wake period and to be a whole number multiple of a duration of the
second sleep/wake period.
[01771 20. The method of clause 19, wherein generating the schedule comprises: configuring the schedule such that a distribution of devices, comprising the first set of devices and the second
set of devices, over event start-time offsets that are dedicated to unicast transmissions is
substantially uniform.
Conclusion
[01781 Although the subject matter has been described in language specific to structural
features and/or methodological acts, it is to be understood that the subject matter defined in the
appended claims is not necessarily limited to the specific features or acts described. Rather, the
specific features and acts are disclosed as exemplary forms of implementing the claims.
Claims (20)
- Claims: 1. A method, comprising: transmitting, according to a schedule, a broadcast transmission to a plurality of devices at a first event start-time offset from among a plurality of event start time offsets indicated by the schedule; transmitting, according to the schedule, a first unicast transmission to a device of the plurality of devices at a second time indicated by a second event start-time offset from among the plurality of event start-time offsets indicated by the schedule; transmitting, according to the schedule, a plurality of unicast transmissions to the plurality of devices, wherein a distribution of numbers of devices associated with event start-time offsets dedicated to unicast transmissions is substantially uniform; and transmitting, according to the schedule, a multicast transmission to at least two devices of the plurality of devices, wherein the multicast transmission is sent at a third time indicated by a third event start-time offset from among the plurality of event start-time offsets.
- 2. The method of claim 1, further comprising: assigning devices of the plurality of devices to event start-time offsets such that a variance of the distribution of numbers of devices associated with each of the plurality of event start-time offsets is under a threshold value.
- 3. The method of claim 1, further comprising: assigning devices of the plurality of devices to event start-time offsets within the schedule such that a difference between a number of devices assigned to the third event start-time offset and a number of devices assigned to a fourth event start-time offset is within a threshold value.
- 4. The method of claim 1, further comprising: assigning devices of the plurality of devices to event start-time offsets within the schedule in a manner that results in each event start-time offset being associated with "n" number of devices or "n" plus 1 number of devices, wherein "n" is an integer that is zero or greater.
- 5. The method of claim 1, wherein a number of event start-time offsets defined within the schedule is based at least in part on one or more factors, the method comprising: a number of battery-powered devices expected to communicate with a mains-powered device; an expected message length used in communications between the battery powered devices and the mains-powered device; and an expected data rate used by the battery-powered devices and the mains-powered device.
- 6. The method of claim 1, additionally comprising: receiving a request from a device to join a network of the plurality of devices; and assigning the device requesting to join the network to an event start-time offset such that a number of devices assigned to each event start-time offset is substantially uniform.
- 7. The method of claim 1, further comprising: detecting that a first device from among the plurality of devices has left a network of the plurality of devices; and changing an event start-time offset of a second device of the plurality of devices that is not leaving the network to an event start-time offset previously used by the first device.
- 8. The method of claim 7, further comprising: prior to changing the event start-time offset of the second device, receiving a request to join the network from the second device.
- 9. The method of claim 1, further comprising: receiving requests from additional devices to join a network of the plurality of devices; and assigning the additional devices to event start-time offsets within the schedule in a manner that results in each event start-time offset being associated with "n" number of devices or "n" plus 1 number of devices, wherein "n" is an integer that is zero or greater.
- 10. The method of claim 1, wherein: a device transmitting according to the schedule is a mains-powered device (MPD); and devices of the plurality of devices are battery-powered devices (BPDs).
- 11. The method of claim 1, further comprising: transmitting a preamble of a packet of the first unicast transmission at the first event start-time offset associated with a first battery-powered device of the plurality of devices; and transmitting portions of the packet other than the preamble of the packet after the second event start-time offset associated with a second battery-powered device of the plurality of devices.
- 12. The method of claim 1, further comprising: sending a second unicast transmission to a third device of the plurality of devices at a time indicated by a third event start-time offset, wherein a radio frequency of the second unicast transmission is based at least in part on a media access control (MAC) address of the third device.
- 13. The method of claim 1, further comprising: transmitting to a first battery-powered device of the plurality of devices according to the first event start-time offset of the schedule during a high-power use period of the first battery-powered device; and transmitting to a second battery-powered device of the plurality of devices according to the second event start-time offset of the schedule during a low-power use period of the first battery-powered device.
- 14. A mains-powered device comprising: one or more processors; and memory communicatively coupled to the one or more processors, the memory storing thereon processor-executable instruction that, when executed by the one or more processors, perform operations comprising: transmitting, according to a schedule, a broadcast transmission to a plurality of devices at a first event start-time offset from among a plurality of event start-time offsets indicated by the schedule; transmitting, according to the schedule, a first unicast transmission to a device of the plurality of devices at a second time indicated by a second event start-time offset from among the plurality of event start-time offsets indicated by the schedule; transmitting, according to the schedule, a plurality of unicast transmissions to the plurality of devices, wherein a distribution of numbers of devices associated with event start-time offsets dedicated to unicast transmissions is substantially uniform; and transmitting, according to the schedule, a multicast transmission to at least two devices of the plurality of devices, wherein the multicast transmission is sent at a third time indicated by a third event start-time offset from among the plurality of event start time offsets.
- 15. The mains-powered device of claim 14, wherein the operations further comprise one of: assigning devices of the plurality of devices to event start-time offsets such that a variance of the distribution of numbers of devices associated with each of the plurality of event start-time offsets is under a threshold value; assigning devices of the plurality of devices to event start-time offsets within the schedule such that a difference between a number of devices assigned to a third event start-time offset and a number of devices assigned to a fourth event start-time offset is within a threshold value; or assigning devices of the plurality of devices to event start-time offsets within the schedule in a manner that results in each event start-time offset being associated with "n" number of devices or "n" plus 1 number of devices, wherein "n" is an integer that is zero or greater.
- 16. The mains-powered device of claim 14, wherein the operations further comprise: receiving a request from a device to join a network of the plurality of devices; and assigning the device requesting to join the network to an event start-time offset such that a number of devices assigned to each event start-time offset is substantially uniform.
- 17. The mains-powered device of claim 14, wherein the operations further comprise: detecting that a first device from among the plurality of devices has left a network of the plurality of devices; and changing an event start-time offset of a second device of the plurality of devices that is not leaving the network to an event start-time offset previously used by the first device.
- 18. The mains-powered device of claim 14, wherein the operations further comprise: receiving requests from additional devices to join a network of the plurality of devices; and assigning the additional devices to event start-time offsets within the schedule in a manner that results in each event start-time offset being associated with "n" number of devices or "n" plus 1 number of devices, wherein "n" is an integer that is zero or greater.
- 19. The mains-powered device of claim 14, wherein the operations further comprise: transmitting to a first battery-powered device of the plurality of devices according to the first event start-time offset of the schedule during a high-power use period of the first battery-powered device; and transmitting to a second battery-powered device of the plurality of devices according to the second event start-time offset of the schedule during a low-power use period of the first battery-powered device.
- 20. Non-transitory computer-readable media storing thereon processor executable instructions that, when executed by one or more processors, cause the one or more processors to perform operations comprising: transmitting, according to a schedule, a broadcast transmission to a plurality of devices at a first event start-time offset from among a plurality of event start time offsets indicated by the schedule; transmitting, according to the schedule, a first unicast transmission to a device of the plurality of devices at a second time indicated by a second event start-time offset from among the plurality of event start-time offsets indicated by the schedule; transmitting, according to the schedule, a plurality of unicast transmissions to the plurality of devices, wherein a distribution of numbers of devices associated with event start-time offsets dedicated to unicast transmissions is substantially uniform; and transmitting, according to the schedule, a multicast transmission to at least two devices of the plurality of devices, wherein the multicast transmission is sent at a third time indicated by a third event start-time offset from among the plurality of event start-time offsets.Itron, Inc. Patent Attorneys for the Applicant SPRUSON&FERGUSON
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2024202460A AU2024202460A1 (en) | 2019-10-31 | 2024-04-16 | Downlink event allocation in a network |
Applications Claiming Priority (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US16/670,046 | 2019-10-31 | ||
| US16/670,137 | 2019-10-31 | ||
| US16/670,137 US11363532B2 (en) | 2019-10-31 | 2019-10-31 | Downlink event allocation in a network |
| US16/670,046 US11438837B2 (en) | 2019-10-31 | 2019-10-31 | Downlink event allocation in a network |
| AU2020375024A AU2020375024B2 (en) | 2019-10-31 | 2020-10-30 | Downlink event allocation in a network |
| PCT/US2020/058289 WO2021087310A1 (en) | 2019-10-31 | 2020-10-30 | Downlink event allocation in a network |
| AU2024202460A AU2024202460A1 (en) | 2019-10-31 | 2024-04-16 | Downlink event allocation in a network |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2020375024A Division AU2020375024B2 (en) | 2019-10-31 | 2020-10-30 | Downlink event allocation in a network |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| AU2024202460A1 true AU2024202460A1 (en) | 2024-05-02 |
Family
ID=73449253
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2020375024A Active AU2020375024B2 (en) | 2019-10-31 | 2020-10-30 | Downlink event allocation in a network |
| AU2024202460A Pending AU2024202460A1 (en) | 2019-10-31 | 2024-04-16 | Downlink event allocation in a network |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2020375024A Active AU2020375024B2 (en) | 2019-10-31 | 2020-10-30 | Downlink event allocation in a network |
Country Status (3)
| Country | Link |
|---|---|
| AU (2) | AU2020375024B2 (en) |
| CA (1) | CA3156407A1 (en) |
| WO (1) | WO2021087310A1 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU2003210465B2 (en) * | 2002-01-08 | 2006-11-02 | Ipr Licensing, Inc. | Maintaining a maintenance channel in a reverse link of a wireless communications system |
| CN103477697B (en) * | 2011-04-02 | 2017-09-05 | 阿尔卡特朗讯 | Time-division slot access and its control for Wireless Telecom Equipment |
| CN104303586B (en) * | 2012-05-09 | 2019-10-18 | 交互数字专利控股公司 | Handle MTC long DRX cycle/sleep length |
-
2020
- 2020-10-30 CA CA3156407A patent/CA3156407A1/en active Pending
- 2020-10-30 AU AU2020375024A patent/AU2020375024B2/en active Active
- 2020-10-30 WO PCT/US2020/058289 patent/WO2021087310A1/en active Application Filing
-
2024
- 2024-04-16 AU AU2024202460A patent/AU2024202460A1/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| CA3156407A1 (en) | 2021-05-06 |
| AU2020375024B2 (en) | 2024-03-07 |
| WO2021087310A1 (en) | 2021-05-06 |
| AU2020375024A1 (en) | 2022-04-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11166088B2 (en) | Discovery mechanism for communication in wireless networks | |
| US11689339B2 (en) | Group acknowledgement message efficiency | |
| US11871345B2 (en) | Downlink event allocation in a network | |
| US11395125B2 (en) | Power-efficient passive discovery by network devices | |
| US11071049B2 (en) | Power-efficient passive discovery by network devices | |
| US11363532B2 (en) | Downlink event allocation in a network | |
| US11399272B2 (en) | Power-efficient passive discovery by network devices | |
| US10833838B1 (en) | Precise time synchronization for communication devices in networks | |
| AU2020375024B2 (en) | Downlink event allocation in a network | |
| US11039227B2 (en) | Packet servicing for enhanced capability in time-slotted systems | |
| US10716057B1 (en) | Power-efficient passive discovery by network devices | |
| AU2020340411A1 (en) | Power-efficient passive discovery by network devices |