U.S. patent application number 13/533428 was filed with the patent office on 2012-11-15 for adaptive network and method.
Invention is credited to Alan Broad, Rahul Kapur, Matt Miller, Jaidev Prabhu, Martin Albert Turon, Ning Xu, Xin Yang.
Application Number | 20120290857 13/533428 |
Document ID | / |
Family ID | 38138865 |
Filed Date | 2012-11-15 |
United States Patent
Application |
20120290857 |
Kind Code |
A1 |
Broad; Alan ; et
al. |
November 15, 2012 |
ADAPTIVE NETWORK AND METHOD
Abstract
A plurality of modules interact to form an adaptive network in
which each module transmits and receives data signals indicative of
proximity of objects. A central computer accumulates the data
produced or received and relayed by each module for analyzing
proximity responses to transmit through the adaptive network
control signals to a selectively-addressed module to respond to
computer analyses of the data accumulated from modules forming the
adaptive network. Interactions of local processors in modules that
sense an intrusion determine the location and path of movements of
the intruding object and control cameras in the modules to retrieve
video images of the intruding object. Multiple operational
frequencies in adaptive networks permit expansions by additional
networks that each operate at separate radio frequencies to avoid
overlapping interaction. Additional modules may be introduced into
operating networks without knowing the operating frequency at the
time of introduction. Remote modules operating as leaf nodes of the
adaptive network actively adapt to changed network conditions upon
awaking from power-conserving sleep mode. New programs are
distributed to all or selected modules under control of the base
station.
Inventors: |
Broad; Alan; (Palo Alto,
CA) ; Kapur; Rahul; (San Francisco, CA) ;
Prabhu; Jaidev; (San Jose, CA) ; Turon; Martin
Albert; (Berkeley, CA) ; Xu; Ning; (San Jose,
CA) ; Yang; Xin; (San Leandro, CA) ; Miller;
Matt; (Grass Valley, CA) |
Family ID: |
38138865 |
Appl. No.: |
13/533428 |
Filed: |
June 26, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13356987 |
Jan 24, 2012 |
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13533428 |
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11433194 |
May 11, 2006 |
8115593 |
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13356987 |
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11345737 |
Feb 1, 2006 |
7760109 |
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11433194 |
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11152350 |
Jun 13, 2005 |
8144197 |
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11345737 |
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11095640 |
Mar 30, 2005 |
7705729 |
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11152350 |
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11096098 |
Mar 30, 2005 |
7369047 |
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11095640 |
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Current U.S.
Class: |
713/300 |
Current CPC
Class: |
G08B 25/009 20130101;
G08B 29/188 20130101; H04W 84/18 20130101; H04W 52/0216 20130101;
G08B 25/10 20130101; Y02D 70/22 20180101; Y02D 30/70 20200801 |
Class at
Publication: |
713/300 |
International
Class: |
G06F 1/26 20060101
G06F001/26 |
Claims
1.-29. (canceled)
30. In an adaptive network of a plurality of interactive modules, a
method comprising: transmitting from at least one module of the
plurality of modules an initial message requesting a response from
others of the plurality of modules within a transmission vicinity
of the at least one initial message transmitting module; receiving,
at the initial message transmitting module, one or more responsive
messages from other modules within the transmission vicinity, each
responsive message including a respective energy expenditure value
representing energy needed to communicate with said initial message
transmitting module; analyzing responsive messages to identify a
module with a lowest energy expenditure value; and communicating
with the identified module from which the responsive message
contained the lowest energy expenditure value.
31. The method according to claim 30 in which each of the plurality
of modules is identified by a unique address included in a
respective responsive message, the method further comprising:
communicating exclusively with the identified module by the unique
address thereof.
32. In each module in an adaptive network of interactive modules, a
method comprising: receiving a request message from an other of the
plurality of modules requesting a responsive transmission; and
transmitting, in response to a request message received thereby, a
responsive message containing an indication of energy expenditure
by said transmitting module to communicate within the adaptive
network along communication channels containing other of the
plurality of modules.
33. The method according to claim 32 in which each of the plurality
of modules is identified by a unique address, wherein the
responsive message comprises an indication of the unique address
thereof.
34.-35. (canceled)
36. The method of claim 30, wherein transmitting the initial
message comprises: sending the initial message to a broadcast
address.
37. The method of claim 36, wherein the initial message comprises a
respective expenditure value set to zero.
38. The method of claim 37, wherein the initial message comprises a
neighborhood list of other modules from which the initial message
transmitting module can receive messages, wherein the neighborhood
list is empty.
39. The method of claim 38, further comprising: adding a source
identifier for each received one or more responsive message to the
neighborhood list.
40. The method of claim 32, wherein the responsive message
comprises a respective expenditure value set to infinity.
41. The method of claim 40, wherein the initial message comprises a
neighborhood list of other modules from which the initial message
transmitting module can receive messages, wherein the neighborhood
list is empty.
42. The method of claim 41, wherein the neighborhood list is
empty.
43. In an adaptive network of interactive modules, each module
configured to: receive a first broadcast initial message from
another module requesting a responsive message in return, the first
broadcast initial message comprising a first cost value and a first
neighborhood list; determine if the received first broadcast
initial message comprises a first cost value set to zero and, if
so, set a source module of the received first broadcast initial
message as a parent node; and send a first responsive message to
the source of the first received broadcast initial message, the
first responsive message comprising a second cost value and a
second neighborhood list including an identifier of the source
module.
44. The adaptive network of claim 43, wherein each module is
further configured to: send a second broadcast initial message
requesting a responsive message, the second broadcast initial
message comprising a second cost value and the second neighborhood
list.
Description
RELATED APPLICATION
[0001] This application is a continuation-in-part of, and claims
priority from, application Ser. No. 11/345,737 entitled
"Interactive Surveillance-Network and Method," filed on Feb. 1,
2006 by A. Broad et al, which is a continuation-in-part of
application Ser. No. 11/152,350 entitled "Adaptive Surveillance
Network and Method," filed on Jun. 13, 2005 by A. Broad, which is a
continuation-in-part of application Ser. No. 11/095,640 entitled
"Surveillance System and Method," filed on Mar. 30, 2005 by A.
Broad et al, which applications are incorporated herein in the
entirety by this reference to form apart hereof.
FIELD OF THE INVENTION
[0002] This invention relates to adaptive networks and more
particularly to a self-adaptive network array of interactive
modules that communicate information to local or central computers
that issue commands for designated modules in the network.
BACKGROUND OF THE INVENTION
[0003] Typical surveillance systems that are used to secure
buildings or borders about a secured area commonly include
closed-circuit video cameras around the secured area, with
concomitant power and signal cabling to video monitors for security
personnel in attendance to observe video images for any changed
circumstances. Additionally, lighting may be installed about the
area, or more-expensive night-vision equipment may be required to
facilitate nighttime surveillance. Appropriate alarms and
corrective measures may be initiated upon observation of a video
image of changed circumstances that prompt human analysis and
manual responses. These tactics are commonly expensive for video
cameras and lighting installations and for continuing labor
expenses associated with continuous shifts of attendant
personnel.
[0004] More sophisticated systems commonly rely upon
image-analyzing software to respond to image changes and reject
false intrusion events while segregating true intrusion events for
controlling appropriate alarm responses. However, such
sophisticated systems nevertheless commonly require permanent
installations of sensors, lighting and cameras with associated
power and cabling that inhibit rapid reconfiguration, and that
increase vulnerability to breakdown due to severing of wiring and
cabling, or to unreliable operations upon exposure to severe
weather conditions.
[0005] In a wireless network of interactive modules, it may be
desirable at times to update the software code that runs on the
individual modules of the network. Since these networks may include
perhaps hundreds of individual modules, manually loading the code
can be time consuming and labor intensive for a field support
person going to each module and via a portable processor
transferring the new code to each module and then having each
module restart with the new code.
[0006] In such wireless networks of interactive modules that
self-adapt to changing transmission conditions, it is desirable to
have most remote modules (also referred herein as `leaf nodes`) to
conserve power while not interacting via transmitted or received
signals by reverting to `sleep` mode of operation. However, over
long sleep intervals conditions for interactive communications may
have changed. Accordingly, it is desirable to awaken a leaf node
via an operating sequence that conserves power through operational
procedures which analyze changed network conditions to restore
interactive operation of the leaf node within the newly-configured
network.
SUMMARY OF THE INVENTION
[0007] In accordance with one embodiment of the present invention;
a plurality of individual mobile transceiver modules may be
deployed around the perimeter of an installation to be secured in
order to sense and transmit information about activity within a
vicinity of a transceiver module. Each module wirelessly
communicates its own sensory data and identity information to one
or more similar adjacent modules, and can relay data signals
received from one or more adjacent modules to other adjacent
modules in the formation of a distributed self-adaptive wireless
network that may communicate with a central computer. Such
interaction of adjacent modules obviates power wiring and signal
cabling and the need for an electromagnetic survey of an area to be
secured, and promotes convenient re-structuring of perimeter
sensors as desired without complications of re-assembling
hard-wired sensors and monitors. In addition, interactions of
adjacent modules establish verification of an intrusion event that
is distinguishable from false detection events, and promote rapid
coordinate location of the intrusion event for follow-up by
computer-controlled video surveillance or other alarm responses.
Multiple modules are deployed within and about a secured area to
automatically configure a wirelessly-interconnected network of
addressed modules that extends the range of individual radio
transmission and identifies addressed locations in and about the
secured area at which disabling or intrusion events occur.
Frequency-shifting schemes among the modules inhibit jamming or
unauthorized disabling of the network, and new modules may be added
to the network in synchronism with prevailing reference frequency.
The network of modules may be expanded about individual base
stations that each operate on separate reference frequencies that
are shifted synchronously in non-overlapping relationship. In this
way, modules operating in one network associated with one base
station are segregated from interaction with modules operating in
another network, even within sufficient proximity to directly
communicate if not so inhibited by distinctive reference
frequencies. Modules are fabricated to include unique ID codes and
ability to operate on a common set of different reference
frequencies in order to be compatibly operable in an assembled
network of such modules. Individual modules within the entire
network may be reprogrammed from the base station over the radio
links between modules.
[0008] Each of the wireless modules may be powered by batteries
that can be charged using solar cells, and may include an
individual video camera, all packaged for mobile deployment,
self-contained operation and interaction with other similar modules
over extended periods of time.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a pictorial block diagram of a plurality of sensor
modules in accordance with an embodiment of the present
invention;
[0010] FIG. 2 is a pictorial illustration of an array of spaced
modules upon initialization of the adaptive network;
[0011] FIG. 3 is a pictorial illustration of the array of FIG. 2
following formation of an interactive network;
[0012] FIG. 4 is an exploded view of one configuration of a sensor
module in accordance with the embodiment of FIG. 1;
[0013] FIG. 5 is a flow chart illustrating an operational
embodiment of the present invention;
[0014] FIG. 6 is a flow chart illustrating another operational
embodiment of the present invention;
[0015] FIG. 7 is a flow chart illustrating operation of a New Node
in accordance with the present invention;
[0016] FIG. 8 is a flow chart illustrating operation 5 of a Joined
Node in accordance with the present invention;
[0017] FIG. 9 is a flow chart illustrating operation of a Base
Station in accordance with the present invention;
[0018] FIGS. 10A, B, C are pictorial illustrations of operating
modes of an interactive surveillance network in accordance with the
present invention;
[0019] FIG. 11 is a pictorial illustration of an expanded network
in accordance with the present invention;
[0020] FIG. 12 is a table showing a sample sequence of
frequency-hopping operation according to the present invention;
[0021] FIG. 13 is a flow chart illustrating an operation of a base
station;
[0022] FIG. 14 is a flow chart illustrating another operation of
the base station;
[0023] FIG. 15 is a flow chart illustrating an accelerated
operation of the base station;
[0024] FIG. 16 is a flow chart illustrating one operational mode;
and
[0025] FIG. 17 is a pictorial illustration of another operational
mode in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0026] Referring now to FIG. 1, there is shown a plurality of
individual sensor modules 9 deployed at spaced locations, for
example, along a peripheral boundary of an area to be secured. Of
course, additional sensor modules 11 may be deployed along pathways
or entryways or other locations within the area to be secured in
order to monitor traffic or other activities.
[0027] Each sensor module 9, 11 includes a proximity sensor 13 that
may be, for example, a passive infrared sensor that responds to the
presence or proximity of a warm object such as an individual,
vehicle, or the like. Alternatively, the proximity sensor 13 may be
an active infrared or radio or ultrasonic sensor that emits a
signal and senses any echo attributable to presence of a reflective
object within a sensing field of view. Of course, other sensors
such as vibration detectors or light detectors may be used to
respond to the presence of an intruding object.
[0028] In addition, each sensor module 9 includes a transceiver 15
that responds to radio transmissions from other similar modules,
and also transmits radio signals to other modules for reception and
relay or re-transmission thereby of such received signals. In this
way, an array of modules 9, 11 forms an interactive, distributed
network that operates self-adaptively on operative modules 9. Thus,
if one module 9, 11 is added, removed or is rendered inoperative,
then adjacent operative modules 9, 11 are capable of interacting to
reconfigure a different distributed array, as later described
herein.
[0029] Each sensor module 9, 11 also includes a processor 17 that
controls operation of the transceiver 15 and proximity sensor 13 to
produce data signals for transmission via the transceiver 15 to one
or more adjacent modules 9, 11. In addition, the processor 17 may
control random recurrences of monitoring events to amass
information about any changes in circumstances associated with
proximate objects, for conversion to data signals to be transmitted
via transceiver 15. Each processor 17 may include alarm utilization
circuitry for initiating alarms, commencing video surveillance via
local video camera 10, or the like, upon command or upon sensing a
change in proximity circumstances. Alternatively, the distributed
network of modules 9, 11 may also communicate with a central
computer 19 via a transceiver 21 acting as a gateway between the
computer 19 and the distributed array of modules 9, 11 for
communicating signals between the computer 19 and the network of
interactive modules 9, 11, 12. Computer 19 may operate on a
database 23 of address or identification code for each module 9,
11, 12 in order to communicate through the network of modules 9, 11
that each have different addresses or identification codes, to a
particular module having a selected address. In this way, each
module 9, 11, 12 may transmit and receive data signals specifically
designating the module by its unique identification code or
address. And, each module 9, 11, 12 is powered by self-contained
batteries 25 and/or photovoltaic cells 27 that also operate to
charge the batteries 25.
[0030] The modules 9, 11 may be disposed within conventional
traffic-marking cones, as illustrated in FIG. 4, for convenient
mobile placement or may be mounted on fence posts, or may be
mounted on spikes driven into the ground within and about an area
to be secured, or may be otherwise suitably mounted in, on and
about areas or passageways that are to be secured against
unauthorized intrusions.
[0031] The plurality of modules 9, 11 may interact, as later
described herein, to distinguish between a false intrusion
detection event and a true event for which alarm and other
responses should be initiated. Certain proximity sensors such as
passive infrared sensors or ultrasonic sensors may respond to a
breeze of different temperature, or to objects blowing by in a
strong wind and thereby create a false intrusion detection.
[0032] In accordance with an embodiment of the present invention,
such false intrusion detections are recognized to be predominantly
random events attributable to stimulation of one sensor and likely
not an adjacent sensor. Thus, correlation of sensor events among
multiple adjacent sensors permits discrimination against false
intrusion detections. Additional information is extracted
throughout the network of multiple sensors, for example, responsive
to an entry location and to movement along a path of travel. The
additional information including, for example, time and duration
and location of one or more sensor stimulations may be transmitted
back to the central computer 19 through the network of modules 9,
11 for computerized correlation analysis of the additional
information to verify a true intrusion event. Alternatively,
modules 9, 11 disposed within or about a small area may communicate
the additional information between modules to correlate the sensor
stimulations and locally perform computerized correlation analysis
within one or more of the processors 17 to verify a true intrusion
event.
[0033] Additionally, the sensor information derived from a
plurality of adjacent or neighboring modules 9, 11 may be analyzed
by the central computer 19, or by local processors 17, to
triangulate the location and path of movement of an intruder for
producing location coordinates to which an installed video
surveillance camera may be aligned. Thus, one or more stand-alone,
battery-operated video surveillance cameras 12 with different
addresses in the network may be selectively activated in an
adjacent region only upon true intrusion events in the region for
maximum unattended battery operation of the cameras 12. Such
cameras 12 of diminutive size and low power consumption (such as
commonly incorporated into contemporary cell phones) may operate
for brief intervals during a true intrusion event to relay image
data through the network of modules 9, 11 for storage in the
database 23 along with such additional information as time of
intrusion, duration and coordinates along a path of movement
through the secured area, and the like. Alternatively, such cameras
10 of diminutive size may be housed in a module 9, 11 or
conventional surveillance cameras 12 may be mounted in protected
areas in association with high-level illumination 14 to be
activated in response to an addressed command from computer 19
following analysis thereby of a true intrusion. Of course,
battery-powered lighting 14 may also be incorporated into each
module 9, 11 to be energized only upon determination by one or more
processors 17, or by central computer 19, 21, 23 of a true
intrusion occurring in the vicinity of such module 9, 11.
Additionally, the video surveillance cameras 10, 12 may be operated
selectively under control of the central computer 19, 21, 23 during
no intrusion activity to scan the adjacent vicinity in order to
update the database 23, 45 with image data about the local
vicinity.
[0034] Referring now to the FIG. 2 illustration of a typical
network that requires initialization, it may be helpful for
understanding the formation of such a network to consider `cost` as
a value or number indicative of the amount of energy required to
transmit a message to another receiving module. Higher cost
translates, for example, into higher energy consumption from
limited battery capacity in each module. In order for an adaptive
network to form, a module (9-1 to 9-5) must select a parent or
superior node to which to forward messages. The radio transmissions
or beacons from neighboring modules (NM) inform a module about how
well the NM's can receive its messages which include cost for the
NM's to forward a message toward a base station, together with a
`hop` count (i.e., number of repeater or message relay operations)
to such base station. This may not be enough information by which a
module as a subordinate node can select a parent or superior node
since a radio link may be highly asymmetrical on such two-way
communications. Thus, a NM may receive clearly from a module but
the module may not receive clearly from the NM. Selecting such NM
as a parent would result in a poor communication link resulting in
many message repeats and acknowledgements at concomitant cost.
[0035] However, such a module (9-1 to 9-5) can also `overhear` a
NM's transmissions that include the NM's neighborhood list (NL) as
a pre-set maximum number, say 16, of modules from which the NM can
receive. For greater numbers of modules, the NM excludes from the
NL those modules with poor or lower-quality reception. Thus, if a
receiving module does not detect its broadcast address or ID in a
potential parent's NL, then that NM will not be selected as a
parent. A base station (e.g., 9-5 connected to central computer 19,
21, 23) may be set to accommodate a larger number of modules in its
NL to handle more children or subordinate modules for greater
prospects of assembling an efficient adaptive network through some
selection of modules and relay operations therebetween.
[0036] Transmitted messages from a module (9-1 to 9-5) contain
several factors, including:
[0037] a) cost, as a number to be minimized which indicates to NM's
the amount of energy required to transmit to a base station. The
cost is a summation of all costs of all `hops` to the base station
(a base station 9-5 has zero cost to forward messages, so its
messages are distinctive from messages of possible parent modules);
and
[0038] b) the number of `hops` to send a message to the base
station; and
[0039] c) a packet sequence number (e.g., 16-bit integer) that is
incremented every time a message is transmitted from the base
station 9-5 or other Module 9-1 to 9-4; and
[0040] d) a neighborhood list (NL) of all other modules in the
vicinity from which the base station or other module can receive,
including: [0041] i) the ID of each NM; and [0042] ii) a reception
estimate of how well a module receives messages from such NM as
determined from processing the sequence numbers in such message
packets to compute a percent of lost packets.
[0043] Therefore, a module (9-1 to 9-5) may calculate a probability
factor (PF) of success in transmitting to a possible parent,
as:
PF=(% of module's packets received by NM).times.(% of possible
parent's packets received by module).
[0044] Each module (9-1 to 9-4) may thus calculate its own cost
(OC) of sending a message to the base station (9-5), as:
OC=cost of NM/PF.
[0045] A module selects lowest OC to send a message.
[0046] As illustrated in FIG. 2, initialization of the network is
facilitated by the base station (9-5) broadcasting a message
including zero costs. In contrast, messages broadcast by all other
modules (9-1 to 9-4) initially include infinite cost (since not yet
determined how to route messages to the base station). And, there
are no entries in the NL in initial broadcast messages. Data
messages from a module are sent with a broadcast address since no
parent has been selected. Modules (e.g., 9-3 and 94) that can
receive base station messages from module 9-5 containing zero cost
information will recognize that they can forward messages to such
base station. Then, messages forwarded by modules 9-3 and 9-4
within the reception vicinity of the base station 9-5 enable the
base station to assemble and include within their messages a NL of
modules (including modules 9-3 and 9-4) that receive the base
station messages. And, these modules then include the base station
and other NM in their NL within broadcast messages. A parent (e.g.,
module 9-4) is then selected as a superior node by other modules as
subordinate nodes whose messages each change from a broadcast
address to the parent's address. The network formation thus
propagates across the array to more remote nodes (e.g., modules 9-1
and 9-2) that are not in the reception vicinity of the base station
9-5.
[0047] Thus, as illustrated in FIG. 3, each module (e.g., module
9-1) may calculate a node cost as the parent's cost plus the cost
of the link to the parent (e.g., 9-2). Similarly, each
communication link toward the base station (e.g., module 9-5) will
be selected by lowest cost (e.g., via module 9-4 rather than via
module 9-3) as the network adapts to the existing transmission
conditions. In the event the cost parameters change due, for
example, to addition or re-location or inoperativeness of a module,
then a transmission path to the base station for a remote module
will be selected on such lower cost (e.g., from module 9-2 via
module 9-3, or from module 9-1 via module 9-4 or 9-3), and such
replaced module will be identified by the absence of its address in
successive transmission by other, adjacent modules or in failure of
response to a polling command from computer 19, 21, 23 (e.g.,
module 9-5).
[0048] Referring now to FIG. 4, there is shown a pictorial exploded
view of one embodiment of the modules according to the present
invention. Specifically, the module 9 may be configured in one
embodiment as a truncated cone with a descending attached housing
16 that is suitably configured for containing batteries 25. The top
or truncation may support photovoltaic or solar cells 27 that are
connected to charge batteries 25. The module 9 conforms generally
to the conical shape of a conventional highway marker 18 and is
dimensioned to fit into the top or truncation of the highway market
18 as one form of support. Such cones may be conveniently stacked
for storage. Of course, the module 9 may be suitably packaged
differently, for example, as a top knob for positioning on a fence
post, or the like.
[0049] The module 9 includes one or more proximity sensors 13 such
as infrared detectors equipped with wide-angle lenses and disposed
at different angular orientations about the periphery of the module
9 to establish overlapping fields of view. One or more miniature
video cameras 10 may also be housed in the module 9 to include
azimuth, elevation and focus operations under control of processor
17 in conventional manner.
[0050] Referring now to FIG. 5, there is shown a flow chart
illustrating one operating embodiment of the present invention in
which a proximity-sensing module detects 35 the transient presence
of an object. Such detection may be by one or more of passive
infrared or acoustic or magnetic sensing, or by active transmission
and reception of transmitted and reflected energy. Such proximity
sensing may be sampled or swept along all directional axes oriented
about the placement of each module. The processor 17 in each module
9, 11 controls operation of the proximity sensor 13 of that module
in order to generate data signals for transmission 39 to adjacent
modules. The processor 17 may establish sensing intervals
independently, or in response 37 to transmission thereto (via
designated address or identification code) of commands from the
central computer 19.
[0051] In addition to transmitting its own generated data signals,
a module 9 receives and relays or re-transmits 41 data signals
received from adjacent modules in the array of modules 9, 11, 12.
Such data signals generated and transmitted or received and
re-transmitted by a module among modules are received 43 by the
central computer 19 which may analyze 47 the data signals to
triangulate the location and path of movement of an intruder, or
may analyze 47 the data signals relative to a database 45 of
information, for example, regarding conditions about each selected
module 9, 11, 12 or to compare intruder images against database
images of the vicinity in order to trigger alarm conditions 49, or
adjust 51 the database, or transmit 53 data or command signals to
all or selected, addressed modules 9, 11, 12. One typical alarm
response 49 may include commands for operation of an installed
video surveillance camera 12 and associated high-level illumination
14 via its designated address as located in the vicinity of a
detected true intrusion.
[0052] Computer analysis of data signals from adjacent addressed
modules 9, 11 may profile the characteristics of changed
circumstances in the vicinity of the addressed modules, and may
identify an intruding object from database information on profiles
and characteristics of various objects such as individuals,
vehicles, and the like. The processor 17 of each module may include
an output utilization circuit for controlling initialization of
alarm conditions, or video surveillance of the vicinity, or the
like. In addition, alarm utilization 49 determined from analyses of
received data signals by the central computer 19 may facilitate
triangulating to coordinates of the intrusion locations and along
paths of movement for controlling camera 12 surveillance, and may
also actuate overall alarm responses concerning the entire secured
area.
[0053] In another operational embodiment of the present invention,
the network assembled in a manner as previously described herein
operates in time synchronized mode to conserve battery power. In
this operating mode, the control station (e.g., computer 19)
periodically broadcasts a reference time to all modules 9, 11, 12
in the network, either directly to proximate modules or via
reception and re-broadcasts through proximate modules to more
remote modules. Modules may correct for propagation delays through
the assembly network, for example, via correlation with accumulated
cost numbers as previously described herein.
[0054] Once all modules 9, 11, 12 are operable in time synchronism,
they reduce operating power drain by entering low-power mode to
operate the transceivers 15 only at selected intervals of, say,
every 125-500 milliseconds. In this wake-up interval of few
milliseconds duration, each transceiver transmits and/or receives
broadcast data messages (in the absence of an intrusion anywhere),
for example, of the type previously described to assess continuity
of the assembled network, or to re-establish communications in the
absence or failure of a module 9, 11, 12 previously assembled
within the network.
[0055] In the presence of an intrusion detected by one module 9,
11, such time synchronism facilitates accurately recording time of
detection across the entire network and promotes accurate
comparisons of detection times among different modules. This
enhances accuracy of triangulation among the modules 9, 11 to
pinpoint the location, path of movement, time of occurrences,
estimated trajectory of movement, and the like, of an actual
intruder. In addition, with surveillance cameras 10, 12 normally
turned off during low-power operating mode, true intrusion as
determined by such time-oriented correlations of intruder movements
among the modules 9, 11, 12 more accurately activates and aligns
the cameras 10, 12 for pinpoint image formation of the intruder
over the course of its movements.
[0056] The imaging of a true intrusion is initiated by a sensor 13
detecting some object not previously present within its sensing
field of view. This `awakens` or actuates the CPU 17 to full
performance capabilities for controlling broadcast and reception of
data signals between and among adjacent modules in order to
determine occurrence of a true intrusion. Thus, modules 9, 11
within the sensor field of view of an intruder may communicate data
signals to verify that all or some of the proximate modules 9, 11
also detect the intrusion. An intrusion sensed by one module 9, 11
and not also sensed by at least one additional module may be
disregarded as constituting a false intrusion or other anomaly
using a triangulation algorithm or routine. The CPU's 17 of the
modules 9, 11 within range of the intruding object determine the
relative locations and control their associated cameras 10, 12 to
scan, scroll and zoom onto the intruder location from the various
module locations. If intrusion activity is sensed during nighttime
(e.g., indicated via solarcell inactivity), then associated
lighting 10, 14 may also be activated under control of the
associated CPU 17. If other adjacent modules do not sense or
otherwise correlate the intruder information, the intrusion is
disregarded as false, and the modules may return to low-power
operating mode.
[0057] Camera images formed of a true intrusion are broadcast or
relayed and re-broadcast over the network to the central computer
19 for comparisons there with image data in database 23 of the
background and surroundings of the addressed modules 9, 11 that
broadcast the intruder image data. Upon positive comparisons of the
intruder image data against background image data, the central
computer 19 may then broadcast further commands for camera tracking
of the intruder, and initiate security alerts for human or other
interventions.
[0058] In time synchronized manner, in the absence of any sensed
intrusion, the central computer 19 periodically broadcasts a
command to actuate cameras 10 of the modules 9, 11, 12 to scan the
surroundings at various times of day and night and seasons to
update related sections of the database 23 for later more accurate
comparisons with suspected intruder images.
[0059] Referring now to FIG. 6, there is shown a flow chart of
operations among adjacent modules 9, 11, 12 in a network during an
intrusion-sensing activity. Specifically, a set of units A and B of
the modules 9, 11, 12 are initially operating 61 in low-power mode
(i.e., and transceiver 15 and camera 10 and lights 14 unenergized,
and CPU 17 in low-level operation), these units A and B may sense
an intruding object 63 at about the same time, or at delayed times
that overlap or correlate as each sensor `awakens` 65 its
associated CPU or micro-processor and transceiver to full activity.
This enables the local CPU's or microprocessors of the units A and
B to communicate 67 the respective intruder information to each
other for comparisons and initial assessments of a true intrusion.
Local cameras and lights may be activated 69 and controlled to form
intruder image data for transmission back through the assembled
network to the central computer 19. There, the image data is
compared 71 with background image data from database 23 as stored
therein by time of day, season, or the like, for determination of
true intrusion. Upon positive detection of an intrusion, commands
are broadcast throughout the network to activate cameras (and
lights, as may be required) in order to coordinate intrusion
movements, path, times of activities, image data and other useful
information to log and store regarding the event. In addition,
alarm information may be forwarded 73 to a control station to
initiate human or other intervention. Of course, the lights 14 may
operate in the infrared spectral region to complement
infrared-sensing cameras 10 and to avoid alerting a human intruder
about the active surveillance.
[0060] In accordance with another embodiment of the present
invention each module 9 is initially fabricated with a unique ID
code (analogous to or associated with its serial number) and with a
capability of operating on one of any number of different operating
RF frequencies. In this way, different distributed networks of such
modules may be operated in coordinated, expanded regions to avoid
significant limitations on number of modules operable in a region
of overall surveillance. Also, such modules that are capable of
operating at different RF frequencies (as the carrier or reference
frequency) can be operated in time-oriented frequency-hopping mode
to inhibit jamming or otherwise disabling an operating network.
[0061] Specifically, then, for a module 9 to be operably compatible
with other modules in an assembled network of modules, each such
module 9 is preconfigured, either as fabricated or as assigned upon
entry into a network (as later described herein), with a few unique
parameters. These include a unique operating frequency (or set of
different operating frequencies) and a Group ID that enables a
module 9 to operate only within its own networks group, a node
address (to identify physical location within a network), and a
network ID as fabricated (analogous to a unique serial number, as
perhaps a 64-bit code). Alternatively, operability of a module 9 on
a particular reference or carrier frequency (or set of such
frequencies) may be all that is required for operation with other
modules 9 in a distributed network. Other of these parameters may
be desirable for exclusion of counterfeit modules from an operable
network, or for efficient, low-power operation, and the like, as
later described herein.
[0062] One overall objective of the present invention is to
conveniently facilitate introduction of a new module into an
operational assembly of such modules without need to preset or
re-set operating parameters to new conditions or values sufficient
to accommodate the new module. For convenient description herein,
the following terms are used to describe the modules 9, the
network, and operations thereof. [0063] Base Station:
computer-based controller and coordinator of overall network
operations. [0064] Joined Node: a module 9 currently operable in a
network that has a NODE ADDR (node address) and GROUP ID (group
identification code) and RADIO FREQUENCY (RF or set of RF operating
frequencies). [0065] New Node: a module 9 seeking to obtain
operational access within a network of Joined Nodes under control
of a Base Station.
[0066] Each operably compatible module also has a unique ID that is
installed as fabricated. Each Base Station stores a list of
compatible ID codes (to inhibit inclusion of counterfeit or
unauthorized modules), and stores one or more Radio Frequencies on
which the network of modules is operable, and also generates and
stores a list of unique Group ID's that can be assigned to modules
9, with an associated physical address by various coordinate, or
other, schemes, to designate the location of a module.
[0067] In operation, as illustrated in the flow chart of FIG. 7, a
new module 9 disposed to enter an operating network of modules as a
New Node initially broadcasts a Join Request within the local
neighborhood of modules on a selected Radio Frequency. In networks
operating at a given time on one of several different Radio
Frequencies (as later described in detail herein), the New Node
broadcasts 83 the Join Request at one of the several different
Radio Frequencies 81. Modules 9 operating in the vicinity of the
New Node routinely operate as previously described herein with
reference to FIGS. 2, 3, 5 and 6 and additionally operate in
accordance with the routine as illustrated in FIG. 8. Thus, a
Joined Node is capable of sensing 85 a Join Request from such New
Node in its vicinity. Upon receipt 87 of a Join Request, such
Joined Node waits a random interval 89 during which it detects
whether an acknowledgement signal was sent by another Joined Node
in the vicinity of the New Node that also received the Join
Request. If no such acknowledgement signal is received 91, then
such Joined Node sends an acknowledgement signal 93 (indicating its
status as the proxy or relaying module for the New Node), and also
sends the Join Request over the operating network of modules 9 to
the Base Station for that network.
[0068] Any other acknowledgement signal received 95 during the
initial wait interval indicates that another Joined Node also
having received the Join Request (and having a shorter random wait
interval) shall serve as the proxy or relaying module for the New
Node.
[0069] The New Node (operating according to the flow chart of FIG.
7) waits 97 to receive an acknowledgement signal and, if one is
received 99, then waits 101 for a response to join the network in
accordance with conditions and provisions established for the New
Node by the Base Station (as later described herein). Receipt of an
acknowledgement signal also indicates a correct selection of a
Radio Frequency on which the network is operating.
[0070] Absence of an acknowledgement signal received within a delay
interval 103 indicates incorrect selection of Radio Frequency
(e.g., at that operational interval of the network), and a new one
of the set of Radio Frequencies is selected 105 by which to again
send a Join Request 83.
[0071] The Joined Node that shall serve as the proxy or relaying
module also sends 107 the Join Request over the network, or Mesh,
to the Base Station (per FIG. 8) and waits 109 for a return
response therefrom through the Mesh.
[0072] As illustrated in the flow chart of FIG. 9, the Base Station
including a gateway 21 and computer 19 with associated database 23
also operates on received Join Requests in addition to operations
as previously described herein. If a Join Request is received 111
over the Mesh, the database 23 including a listing of unique ID's
for authentic modules is checked 113 and, if verified as authentic
by entry on the unique ID list 115, the Base Station computer 19
assigns and sends 117 a Network ID, or Node ID, as part of an
acceptance signal back to the New Node over the Mesh. A Network or
Node ID may be selected, for example, from a stored listing in the
Base Station of Nodes not `heard` from in the Mesh for some period
of time (as an indication that the New Node replaces a failed
node). Alternatively, a New Network ID or Node ID may be
established corresponding to a known physical location in the
network.
[0073] An unauthentic unique ID for the New Node (e.g., not listed
in the database) may determine that a rejection signal should be
sent 121 over the Mesh back to the New Node. Alternatively, if the
Base Station is to accommodate expansions 123 of the network, then
a new unique ID may be added to the database of unique ID's 125,
and a new Network ID may be added to the database (e.g., also
associated with physical location of the New Node) for transmission
back over the Mesh with an acceptance signal 117. The Base Station
is then available for continuing control of the network or Mesh as
newly configured with the New Node in accordance with operational
activities as previously described herein, and is also then
available 119 to receive new Join Requests.
[0074] As illustrated in the flow chart of FIG. 8, the Joined Node
serving as the proxy or relaying module receives back the
acceptance (or rejection) signal 127 from the Base Station via the
Mesh and relays or resends 129 the acceptance (or rejection)
message to the New Node. Thereafter, the Joined Node serving as the
proxy or relaying mode is available to operate within the Mesh or
network as previously described herein, and also awaits 131 new
Join Requests.
[0075] As illustrated in the flow chart of FIG. 7, the New Node
receives the join response 133 after an interval of processing at
the Base Station (as previously described) and transmission through
the Mesh. If no such response 133 is received after a delay
interval 135, then the New Node is activated to reset to operate on
another one of the set of Radio Frequencies to again send a Join
Request 83 in the manner as previously described herein. All
available Radio Frequencies may be utilized in this manner in order
to attain an acceptance signal. After all available Radio
Frequencies are utilized in this manner without a resultant
acceptance signal, the New Node delays commencing a new cycle of
broadcasting a Join Request separately and sequentially on each
available Radio Frequency. After each such cycle of broadcasting a
Join Request with no resultant acceptance signal, the New Node
extends the delay interval prior to starting a new cycle of
broadcasting a Join Request to conserve power and to enhance
statistical probability of matching a reference or carrier Radio
Frequency on which the Mesh is momentarily operating.
[0076] In the event a response is received 133 that rejects 137
entry into the Mesh or network, then the New Node may store
indication 139 of the group (or assembled network) from which it
was rejected and again initiate a new Join Request using another
selected Radio Frequency (for possible entry into another assembled
network, or group) that is also operational in the vicinity within
the broadcast range of the New Node.
[0077] Upon receipt by the New Node of an acceptance signal, the
New Node also receives a Group ID code or designation for its
status and location in the assembled network or mesh. The Group ID
may incorporate the unique ID as a mechanism for indicating that
the acceptance signal is intended only for such New Node.
Additionally, the frequency (if selected from a set of Radio
Frequencies) designates the operational frequency to be used when
communicating thereafter with any adjacent modules (not necessarily
only the proxy or relaying module) during normal Mesh operation.
The assigned Group ID and associated physical location within the
Mesh now identified at the Base Station is beneficial, for example,
for initiating verifying interrogations regarding a suspected
intrusion at or near the location of such New Node, as by
activating a video camera or other sensors, or the like.
[0078] Each module may be advantageously fabricated with ability to
operate on any one of several different Radio Frequencies to
conveniently facilitate `matching` a New Node with any Mesh
operating on at least one of the set of Radio Frequencies, without
having to retain records of which module 9 as fabricated was set
for operation in which Mesh at what one of such Radio
Frequencies.
[0079] Additionally, such modules 9 operable on different ones of a
set of Radio Frequencies greatly enhances immunity to jamming and
the exclusion of unauthorized modules 9 from joining an operational
network. Specifically, as indicated in FIGS. 10A, B, C, a pictorial
illustration of a typical network of distributed modules 9 and Base
Station 19, 21, 23 that may receive a Join Request broadcast by
module 9a as a New Node. In this mode of operation, module 9b as
the Joined Node and proxy (having shorter random delay time than
module 9c that also received the Join Request) transmits its
acknowledgement of the Join Request received (as described-above),
and also forwards the Join Request through the network toward the
Base Station 19, 21, 23. After processing in the Base Station (as
described above), the acceptance signal is returned to the Joined
Node 9b that then relays the acceptance signal (incorporating the
Unique ID as the assigned Network ID) to the New Node 9a (as
described above). Any unauthorized or incompatible parameters
(e.g., not a proper Radio Frequency, not a listed or authorized
Unique ID, or the like) inhibits the New Node 9a from gaining
operational access to the assembled network.
[0080] Another overall objective of the present invention is to
conveniently reprogram individual modules with updated software
using the radio links established between modules and between a
module and the base station. New software to be loaded into each of
the modules 9, 11, 12 is presented to the base station 19, 21, 23
that maintains a list in the database 23 of the network ID's for
all operative modules that are active in the network. The computer
19 in the base station breaks up the new software into small code
capsules that can be transmitted within a single radio packet
between modules.
[0081] Although the base station may maintain a list of the network
ID's of all the operative modules, there may not be corresponding
geographical information about the location of each module 9, 11,
12. However, the base station 19, 21, 23 maintains information
about relative depth of a module within the network, i.e., the
number of "hops" a module is displaced from the base station. Thus,
a module 9, 11, 12 that is displaced via 2 hops from the base
station requires two radio transmissions and an intermediate module
serving to relay the radio transmission to the ultimate designated
recipient module. Multiple transmission hops and intermediate
modules along a transmission path from the base station to a module
designated by its network ID consume battery power, so should be
managed in an energy-efficient manner.
[0082] Each module 9, 11, 12 includes a microprocessor and a
limited program memory that is to be updated by new software.
Additionally, each module typically has limited battery power so
commonly operates in "sleep" mode at low power consumption awaiting
sensor or transmission stimulus to trigger full-power operation.
Over-The-Air Programming (OTAP) of remote modules 9, 11, 12 from
the base station is achieved in accordance with one embodiment of
the present invention by storing an OTAP utility or service code in
an external memory in each module for access when needed during
usually infrequent occasions of reprogramming the module. This
obviates the need to consume operational program memory and SRAM
memory of a module with infrequently-used OTAP utility program.
Instead, such utility program can be loaded from external memory
into operational program memory and SRAM only as needed during
reprogramming events.
[0083] Thus, in one embodiment of the present invention as
illustrated in FIG. 13, a reprogram for all (or selected subset) of
modules 9, 11, 12 is loaded 161 (as a code image) into the base
station 19, 21, 23 with a list 163 of the modules identified by
their network ID's that are to be reprogrammed. Then, as
illustrated in FIG. 14, the base station transmits a message 165 to
alert the identified modules (or motes) of the upcoming program
updating requirement, and to load the OTAP program 167 (from
external memory) into working memory. Low-power operation of the
modules 9, 11, 12 usually limits available bandwidth and radio
packet throughput, with resultant extended time to reprogram the
modules. Thus, the OTAP utility program also initiates full-power
operation for higher throughput rate of radio packets. As
previously described herein, the base station 19, 21, 23 breaks up
the new program into capsules of the program of bit-size small
enough to be contained within radio packets that are transmitted
between modules. Thus, greater rates of capsules/second
transmission are achieved at high power, higher bandwidth
operations of the modules. After the new program is received, the
network of modules is commanded by the base station communicating
through the modules as previously described herein to load the new
program and return to the low-power sleep-mode operating state.
[0084] In accordance with another embodiment of the present
invention, the reprogramming of the modules is accelerated using
"promiscuous listening" in a manner as illustrated in FIG. 15. That
is, a module which is likely to require reprogramming, and that
receives or overhears the radio transmission of program capsules
being transmitted between other modules, will store the overheard
program capsules. Since the base station maintains data indicative
of the relative depth of designated modules within the network
(i.e., by "hop" count), the new program is initially sent to
modules at highest hop counts 171. This assures that intermediate
modules as relayers of capsule transmissions, as well as adjacent
modules in reception range, also receive and can store the
transmitted program or code capsules. With high probability that
such modules will also require the updated program, these modules
may store the overheard program capsules in advance of being
designated to receive specific radio packets. After the base
station has sent code capsules to the intended module of high-order
hop count, the other modules are polled 173 by the base station to
determine which code capsules each module still requires. Only
missing code capsules 175 are then sent by the base station to a
designated module (usually of lower hop count). In this way, all
modules can be reprogrammed more rapidly than by iterative,
repetitious complete transmission of the same code capsules to each
designated module.
[0085] As the new code image (i.e., the new software) is loaded
into modules in the manner as described above, the modules switch
back to low-power operating state within the network. Thus, some
modules earlier loaded with code capsules will operate in low-power
(usually low bandwidth) network state while other modules continue
operating in high power state, with resultant loss of transmitted
messages and possible disruption of the network. In accordance with
an embodiment of the present invention, a re-boot command is sent
by the base station to the modules of the network following loading
of the new code image to all modules. The reboot command includes a
variable delay that is longer for modules of higher hop count, to
accommodate longer transmission times of the reboot command through
intermediate, relaying modules.
[0086] In accordance with another embodiment of the present
invention, as illustrated in the pictorial diagram of FIG. 11, a
plural number of separately operable networks may be assembled
within each of the Meshes 141, 143, 145 using compatible modules 9
under control of a separate Base Station 147, 149, 151 in each
Mesh. Each of the Base Stations 147, 149, 151 and the associated
Mesh 141,143, 145 are operable at a plurality of different Radio
Frequencies as the reference or carrier frequency over which the
communication channels throughout the network are established (as
discussed above). A particular set of a plural number of Radio
Frequencies (selected, for example, from within the allowable
bandwidth of the Business. Radio Service established by the Federal
Communications Commission) and designated as frequencies 1, 2, 3
and 4 are shown listed in the attached Table of FIG. 12. Of course,
more than 4 Radio Frequencies and more than 4 networks may be used.
These frequencies are shifted in successive time intervals, for
example, in accordance with the sequence illustrated in the Table
to avoid overlapping interactions between even adjacent modules
operating at different Radio Frequencies in separate networks. The
synchronizing of such frequency shifts is accomplished via signals
transmitted between Base Stations 147, 149, 151 along the
communication links 153 using any conventional schemes and
protocols. Alternatively, frequency shifts to encoded Radio
Frequencies may be accomplished in random or pseudo-random manner
using such coded information distributed to modules and Base
Station of each network at selected periodic or aperiodic
intervals. In this way, interactions are inhibited even at adjacent
locations between otherwise compatible modules operating in
different networks at different Radio Frequencies at any given
time.
[0087] In another embodiment of the present invention, an adaptive
network of a plurality of modules, for example as illustrated in
FIG. 1, includes at least one remote module such as 11, 12 that is
not commonly engaged in reception and transmission of signals as
part of a communication channel across the network between a base
station and other modules. Such modules (referred to herein as
`leaf nodes`) are commonly disposed at an end of communication
branch channels, and are typically less active in the network of
modules. A module operating as a leaf node in an adaptive network
may therefore conserve power by reverting to a `sleep` mode of
operation during which low-power operation preserves responsiveness
only to broadcast signals containing the specific address or other
identification code of the leaf node. In this way, a leaf node may
conserve battery power for longer, lower-maintenance operation in
the network. Additionally, such modules operating as leaf nodes may
remain in `sleep` mode for extended periods of time of the order of
hours or days, during which time the network of modules, or at
least transmission conditions within the network may have
changed.
[0088] It is desirable to have a leaf node locate and store
information representing a best radio link between the leaf node
and an adjacent module prior to the leaf node reverting to a sleep
mode of operation. In this way, upon awakening from the sleep mode,
the leaf node re-establishes a communication channel with the
adjacent modules about which the leaf node previously stored
information about the associated radio link. In the absence of any
changes in the adaptive network of modules, and in the absence of
any corruption of transmission conditions, the leaf node may
re-establish communications over the radio link of stored
information using minimal few transmission exchanges, with
concomitant conservation of battery power.
[0089] However, under changed conditions within the network of
modules, information about a best radio link to an adjacent module
as previously stored prior to reversion to the sleep mode may no
longer be operational. Quality of radio links can change quickly
attributable to objects moving through; or newly positioned in a
transmission path, interference from other sources of radio
signals, and the like. In such changed circumstances, the leaf node
upon awakening must select a new adjacent module before
successfully communicating again within the network of modules.
Additional energy is expended transmitting signals to the module
previously in adjacent relationship before the leaf node can
determine absence, or poor quality, of a radio link to the adjacent
module associated with the stored information. Also, if the leaf
node is normally awakened by reception of a command transmitted
through the network of modules from a base station, the leaf node
may perpetuate the sleep mode of operation without a recognition of
the failed radio link to the adjacent module.
[0090] In accordance with one embodiment of the present invention,
a module that is operable in a self-adaptive mesh network is
operable as a leaf node (e.g. as installed, or as more remote
modules are removed or rendered inoperable). As illustrated in the
flow chart of FIG. 16, a module that awakens from a sleep mode must
find a parent node (i.e., a best radio-approximate adjacent module)
with which to communicate. Such awakening of a module may occur at
internally-timed intervals, or upon sensing of an event, or the
like, and initiates turn-on of its transmitter 200 to transmit 202
a brief burst of messages 204 of a type characterized as FP (Find
Parent), containing N number of such messages to all possible
parent modules within radio range. The time intervals (TI) between
each of the N messages are the same, and all modules use the same
number N of messages spaced by the same TI. Thus, all possible
parent modules expect FP-type messages to contain N messages at TI
spacing in a received burst message. Optionally, a succession of
the N messages in a burst may be transmitted at progressively lower
(or greater) signal strengths, and contain information such as an
address or identification code that identifies the leaf-node
module, and also contain information about which of the number N
the message represents (i.e., 1 to N).
[0091] All modules in the vicinity as possible parent nodes monitor
FP bursts and count the number of messages (up to N) received
within the burst. The number of messages received and counted are
logically calculated against known N to yield a percentage of
messages actually received. Additionally, the possible parent
modules need only monitor for the known interval (TI.times.N) to
avoid excessive receiver operation with concomitant waste of
energy.
[0092] All possible parent modules in the radio-receiving vicinity
of the transmitting leaf node may determine 208 (after the full
TI.times.N transmission interval) that some messages are missing
from the received burst, and transmit a Located Parent-type (LP)
message 210 containing Percent Received (PR) information.
Additionally, such LP-type message may also include a number of
`hops` (and hence COST) required for such possible parent module to
relay communications through the mesh network to a base
station.
[0093] The leaf node reverts to receiver operation following its
transmission of the FP-type message and before returning to `sleep`
mode in order to monitor 212 responses broadcast by possible parent
modules. Among LP-type messages thus received containing PR and
COST information associated with each possible parent module, the
leaf node may also monitor received radio signal strength (RSSI) of
the reply/received LP-type message to determine quality of
communications over radio links with each responding possible
parent module. The possible parent module preferably with the best
PR, lowest COST, and highest RSSI (or selected weighted
combinations thereof) is selected 214 by the leaf node to serve as
its parent node. This procedure to identify a parent node results
in low energy consumption since the time to locate a parent node is
determined substantially by how rapidly the leaf node can broadcast
the burst of N messages and remain awake to monitor the responses.
Additionally, this procedure results in finding a quality
bidirectional radio link for both transmitting and receiving
messages. Identification information in the LP-type message
received from a selected parent node is then stored by the leaf
node prior to reverting to sleep mode of operation. Similarly, the
selected parent node stores identification information about the
leaf node to facilitate efficient establishment of a communication
channel between them in a subsequent interval.
[0094] In another embodiment of the present invention a leaf node
may communicate with a base station across a mesh network in
accordance with operating procedures, for example as pictorially
illustrated in FIG. 17. Specifically, the central computer 220 that
commands a mesh network of interactive modules, including at least
one module that operates as a leaf node, may condition the base
station 222 to execute a command to a specific leaf node in
response to its next transmission across the mesh network. Such
next transmission by the specified leaf node may be predicted with
respect to wake up from sleep mode of known timing and duration, or
may be random in response to a sensed condition. A leaf node
transmission is progressively relayed via one or more radio links
between modules of the mesh network in a manner as previously
described herein.
[0095] The command 221 from the central computer 220 to the base
station 222 (RQST_WAKEUP) alerts the base station to transmit a
command to the specified leaf node, in response to its next
transmission, that the leaf node must remain awake to receive
following messages. Upon awaking from sleep mode, leaf node 11
transmits a data packet (Data Pkt Xmit) 224 that is relayed through
one or more `hops` among communication channels between modules in
a manner as previously described herein. In response to receipt of
such data packet at the base station 222, it responds to the
command previously received (and buffered or stored) from the
central computer to return an acknowledgment message (B2N_Ack) 226
that is modified to include the command for the leaf node to remain
awake (i.e., not to revert to sleep mode). Such message is
communicated to the leaf node via one or more `hops` among
communication channels between modules (or motes 228) in a manner
as previously described herein.
[0096] Receipt of the modified acknowledgment message 226 by the
specified leaf node 11 includes an initiated transmission of a
response message (MSG_AWAKE) 230 that is communicated over the mesh
network to the base station 222 for relay back to the central
computer 220. The specified leaf node may now be commanded by the
central computer 220 to perform some particular operation such as
update internal program, report a monitored condition, or the like.
Upon completion of commands from the central computer 220 in this
manner, the leaf node may revert to sleep mode upon command, or
upon completion of commanded operation, or the like.
[0097] Therefore, one or more modules operating in a self-adaptive
mesh network of such modules may conserve limited battery power by
reverting to sleep-mode operation and by actively adapting to any
changes in the adaptive mesh network upon awakening from sleep
mode. In addition, sensor modules deployed in a such a
self-adaptive mesh network greatly facilitate establishing
surveillance within and around a secure area without time-consuming
and expensive requirements of hard-wiring of modules to a central
computer. In addition, data signals generated by, or received from
other adjacent modules and re-transmitted among adjacent modules
promotes self-adaptive formation of distributed sensing networks
that can self configure around blocked or inoperative modules to
preserve integrity of the surveillance established by the
interactive sensing modules. Adaptive activity of a new node
seeking operable access to an existing network facilitates
engagement of a standard module into unique operational
relationship within the network. Modules operating as leaf nodes of
the network conserve power during sleep mode and actively adapt to
changed network conditions upon awakening from sleep mode.
* * * * *