U.S. patent application number 14/656323 was filed with the patent office on 2015-07-02 for network association of communication devices based on attenuation information.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Srinivas Katar, Richard Ernest Newman, Lawrence Winston Yonge, III.
Application Number | 20150189581 14/656323 |
Document ID | / |
Family ID | 46750471 |
Filed Date | 2015-07-02 |
United States Patent
Application |
20150189581 |
Kind Code |
A1 |
Katar; Srinivas ; et
al. |
July 2, 2015 |
NETWORK ASSOCIATION OF COMMUNICATION DEVICES BASED ON ATTENUATION
INFORMATION
Abstract
A client network device may associate with a service provider to
receive a service. For example, a client network device may
transmit a number of broadcast messages to one or more service
providers. The number of broadcast messages may be determined
based, at least in part, on a first communication parameter
received from at least one of the service providers. The client
network device may receive first attenuation information from a
first service provider after transmitting the number of broadcast
messages. The client network device may associate with the first
service provider based, at least in part, on the first attenuation
information. In one example, a vehicle can associate with a
charging station in a charging facility to securely communicate
with and receive electric power from the charging station.
Inventors: |
Katar; Srinivas; (Fremont,
CA) ; Yonge, III; Lawrence Winston; (Summerfield,
FL) ; Newman; Richard Ernest; (Gainsville,
FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
46750471 |
Appl. No.: |
14/656323 |
Filed: |
March 12, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13564358 |
Aug 1, 2012 |
9021278 |
|
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14656323 |
|
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|
|
61522184 |
Aug 10, 2011 |
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Current U.S.
Class: |
714/748 ;
370/312; 713/176 |
Current CPC
Class: |
Y02T 10/7072 20130101;
H04L 1/08 20130101; Y02B 90/20 20130101; Y04S 40/124 20130101; H02J
7/00036 20200101; H02J 13/00016 20200101; Y02T 90/14 20130101; Y02T
90/12 20130101; Y02T 90/167 20130101; G06F 1/3203 20130101; H02J
7/00045 20200101; H04W 48/18 20130101; H04L 63/0823 20130101; H04L
67/125 20130101; H04H 20/71 20130101; H04L 9/3247 20130101; Y02T
90/16 20130101; H04L 2209/84 20130101; H04W 12/0609 20190101; H02J
13/0062 20130101; Y02T 10/70 20130101; H02J 7/00047 20200101; B60L
53/65 20190201; B60L 53/67 20190201; H04W 52/18 20130101; Y04S
30/12 20130101; Y04S 30/14 20130101; H04L 9/3263 20130101 |
International
Class: |
H04W 48/18 20060101
H04W048/18; H04W 52/18 20060101 H04W052/18; B60L 11/18 20060101
B60L011/18; H04H 20/71 20060101 H04H020/71; H04L 9/32 20060101
H04L009/32; H04L 1/08 20060101 H04L001/08; H04W 12/06 20060101
H04W012/06 |
Claims
1. A method for network association, the method comprising:
transmitting a number of broadcast messages from a client network
device to at least a subset of a plurality of service providers,
the number of broadcast messages determined based, at least in
part, on a first communication parameter received from at least one
of the plurality of service providers; receiving, at the client
network device, first attenuation information from a first service
provider of the plurality of service providers after transmitting
the number of broadcast messages; and associating with the first
service provider based, at least in part, on the first attenuation
information.
2. The method of claim 1, further comprising: transmitting, from
the client network device, a request for communication parameters;
and receiving the first communication parameter after transmitting
the request.
3. The method of claim 2, further comprising: initiating, after
transmission of the request, a time interval for receiving at least
one communication parameter; determining the number of broadcast
messages to transmit from the client network device in response to
receiving the first communication parameter before the time
interval elapses; and retransmitting the request in response to not
receiving any communication parameters before the time interval
elapses.
4. The method of claim 1, wherein the first communication parameter
includes at least one member of the group consisting of the number
of broadcast messages to transmit to the first service provider, a
maximum time interval for transmitting the number of broadcast
messages, and an indication of whether the first service provider
supports secure communications.
5. The method of claim 1, further comprising transmitting a request
message from the client network device to the first service
provider, the request message requesting a first network parameter
to associate with the first service provider.
6. The method of claim 5, further comprising: receiving, at the
client network device, a confirmation message from the first
service provider, the confirmation message including the first
network parameter; and joining a network associated with the first
service provider based, at least in part, on the first network
parameter.
7. The method of claim 5, wherein the first network parameter
includes at least one member of the group consisting of a network
identifier, a device address, and security information associated
with the first service provider.
8. The method of claim 5, further comprising: receiving, at the
client network device, a notification message from the first
service provider, the notification message indicating that the
client network device should associate with a second service
provider of the plurality of service providers and including a
second network parameter associated with the second service
provider; and joining a network of the second service provider
based, at least in part, on the second network parameter.
9. The method of claim 1, further comprising: transmitting a first
amplitude map associated with the client network device to the
first service provider; receiving, at the client network device, a
second amplitude map associated with the first service provider;
and determining a transmit power for transmissions to the first
service provider based, at least in part, on the first amplitude
map and the second amplitude map.
10. The method of claim 1, wherein transmitting the number of
broadcast messages comprising: transmitting a first set of
broadcast messages at a first transmit power from the client
network device to at least the subset of the plurality of service
providers; and transmitting a second set of broadcast messages at a
second transmit power in response to not receiving a response
message from any of the plurality of service providers, wherein the
second transmit power is greater than the first transmit power.
11. The method of claim 1, further comprising: determining, by the
client network device, second attenuation information associated
with the first service provider based, at least in part, on a
transmission received at the client network device from the first
service provider, wherein associating with the first service
provider is based, at least in part, on the first attenuation
information and the second attenuation information.
12. The method of claim 1, further comprising: initiating, after
transmission of the number of broadcast messages, a time interval
for receiving attenuation information from at least one of the
plurality of service providers; associating with the first service
provider in response to receiving the first attenuation information
before the time interval elapses; and retransmitting the number of
broadcast messages in response to not receiving any attenuation
information before the time interval elapses.
13. The method of claim 1, further comprising transmitting security
information associated with the client network device to the first
service provider for validating the client network device.
14. The method of claim 1, further comprising: determining, by the
client network device, that the first service provider supports
secure communications based, at least in part, on the first
communication parameter; transmitting first security information
associated with the client network device to the first service
provider; receiving, at the client network device, second security
information associated with the first service provider; signing,
using the first security information, a first transmission from the
client network device to the first service provider; and receiving,
at the client network device, a second transmission signed with the
second security information from the first service provider.
15. The method of claim 1, wherein the client network device is a
vehicle and the plurality of service providers are charging
stations.
16. The method of claim 1, wherein the client network device is a
plug-in electric vehicle (PEV) and the plurality of service
providers are electric vehicle supply equipment (EVSE)
stations.
17. A method for network association, the method comprising:
transmitting a first communication parameter from a first service
provider to a client network device after receiving a request for
communication parameters from the client network device; receiving,
at the first service provider, one or more broadcast messages from
the client network device; determining first attenuation
information associated with the first service provider based, at
least in part, on the one or more broadcast messages; transmitting
the first attenuation information from the first service provider
to the client network device; and receiving, at the first service
provider, a request message from the client network device after
transmitting the first attenuation information, the request message
requesting the first service provider to associate with the client
network device.
18. The method of claim 17, further comprising: determining, by the
first service provider, whether the first attenuation information
exceeds a threshold; determining to transmit the first attenuation
information to the client network device in response to determining
that the first attenuation information does not exceed the
threshold; and determining not to transmit the first attenuation
information to the client network device in response to determining
that the first attenuation information exceeds the threshold.
19. The method of claim 17, further comprising: determining, by the
first service provider, second attenuation information associated
with a second service provider; determining, by the first service
provider, that the client network device should associate with the
second service provider based, at least in part, on comparing the
first attenuation information and the second attenuation
information; determining, by the first service provider, a network
parameter associated with the second service provider; and
providing the network parameter to the client network device.
20. The method of claim 17, further comprising: receiving, at the
first service provider, first security information associated with
the client network device; transmitting second security information
associated with the first service provider from the first service
provider to the client network device in response to receiving the
first security information; determining to sign, using the second
security information, subsequent transmissions from the first
service provider to the client network device; and determining to
encrypt, using the first security information, the subsequent
transmissions.
21. The method of claim 17, further comprising: transmitting, by
the first service provider, a confirmation message to the client
network device, the confirmation message including a network
parameter for associating with the first service provider; and
establishing a logical network with the client network device
based, at least in part, on the network parameter.
22. The method of claim 21, further comprising: authenticating, by
the first service provider, the client network device after
establishing the logical network with the client network device;
and providing a service from the first service provider to the
client network device after authenticating the client network
device.
23. The method of claim 17, further comprising: determining, by the
first service provider, whether to associate with the client
network device based, at least in part, on the first attenuation
information; in response to determining to associate with the
client network device, transmitting, from the first service
provider, a network parameter associated with the first service
provider to the client network device; and configuring the first
service provider with the network parameter to form a logical
network with the client network device.
24. The method of claim 17, further comprising: utilizing an
out-of-band communication medium to validate the client network
device and to determine whether to associate with the client
network device.
25. A client network device comprising: a processor; and a memory
for storing instructions which, when executed by the processor,
cause the client network device to: transmit a number of broadcast
messages to at least a subset of a plurality of service providers,
the number of broadcast messages determined based, at least in
part, on a first communication parameter received from at least one
of the plurality of service providers; receive first attenuation
information from a first service provider of the plurality of
service providers after transmitting the number of broadcast
messages; and associate with the first service provider based, at
least in part, on the first attenuation information.
26. The client network device of claim 25, wherein the
instructions, when executed by the processor, further cause the
client network device to: transmit a request for communication
parameters; and receive the first communication parameter after
transmitting the request.
27. The client network device of claim 25, wherein the
instructions, when executed by the processor, further cause the
client network device to: initiate, after transmission of the
number of broadcast messages, a time interval for receiving
attenuation information from at least one of the plurality of
service providers; associate with the first service provider in
response to receiving the first attenuation information before the
time interval elapses; and retransmit the number of broadcast
messages in response to not receiving any attenuation information
before the time interval elapses.
28. A non-transitory computer-readable medium for storing
instructions which, when executed by a processor of a client
network device, cause the client network device to: transmit a
number of broadcast messages to at least a subset of a plurality of
service providers, the number of broadcast messages determined
based, at least in part, on a first communication parameter
received from at least one of the plurality of service providers;
receive first attenuation information from a first service provider
of the plurality of service providers after transmitting the number
of broadcast messages; and associate with the first service
provider based, at least in part, on the first attenuation
information.
29. The non-transitory computer-readable medium of claim 28,
wherein the instructions, when executed by the processor of the
client network device, cause the client network device to: transmit
a request for communication parameters; initiate, after
transmission of the request, a time interval for receiving at least
one communication parameter; determine the number of broadcast
messages to transmit from the client network device in response to
receiving the first communication parameter before the time
interval elapses; and retransmit the request in response to not
receiving any communication parameters before the time interval
elapses.
30. The non-transitory computer-readable medium of claim 28,
wherein the instructions, when executed by the processor of the
client network device, cause the client network device to: transmit
a request message to the first service provider, the request
message requesting a first network parameter to associate with the
first service provider; receive a confirmation message from the
first service provider after transmitting the request message, the
confirmation message including the first network parameter; and
join a network associated with the first service provider based, at
least in part, on the first network parameter.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 13/564,358 filed on Aug. 1, 2012which claims the priority
benefit of U.S. Provisional Application No. 61/522,184 filed on
Aug. 10, 2011.
BACKGROUND
[0002] Embodiments of the inventive subject matter generally relate
to the field of communication networks and, more particularly, to a
mechanism for attenuation level based association in communication
networks.
[0003] An electric vehicle typically charges from a conventional
power outlet or a dedicated charging station. Prior to receiving
power from the charging station, the electric vehicle can connect
to and associate with an appropriate charging station in a charging
facility. The charging station can also ensure that the user of the
electric vehicle has proper authorization to receive the electric
power and to pay for the received electric power.
SUMMARY
[0004] Various embodiments for network association of communication
devices are disclosed. In one embodiment, a method for network
association comprises: transmitting a number of broadcast messages
from a client network device to at least a subset of a plurality of
service providers, the number of broadcast messages determined
based, at least in part, on a first communication parameter
received from at least one of the plurality of service providers;
receiving, at the client network device, first attenuation
information from a first service provider of the plurality of
service providers after transmitting the number of broadcast
messages; and associating with the first service provider based, at
least in part, on the first attenuation information.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The present embodiments may be better understood, and
numerous objects, features, and advantages made apparent to those
skilled in the art by referencing the accompanying drawings.
[0006] FIG. 1 is an example conceptual diagram illustrating an
association procedure between an electric vehicle and one or more
charging stations in a charging facility;
[0007] FIG. 2 is a flow diagram illustrating example operations of
a client network device executing an association procedure to
establish a communication link with a service provider of a
communication network;
[0008] FIG. 3 is a continuation of FIG. 2 and also illustrates
example operations of the client network device executing the
association procedure to establish the communication link with a
service provider of the communication network;
[0009] FIG. 4 is a flow diagram illustrating example operations of
a service provider executing an association procedure with a client
network device;
[0010] FIG. 5 is a continuation of FIG. 4 and also illustrates
example operations of the service provider executing the
association procedure with the client network device; and
[0011] FIG. 6 is a block diagram of one embodiment of an electronic
device including an attenuation level based association mechanism
in a communication network.
DESCRIPTION OF EMBODIMENT(S)
[0012] The description that follows includes exemplary systems,
methods, techniques, instruction sequences, and computer program
products that embody techniques of the present inventive subject
matter. However, it is understood that the described embodiments
may be practiced without these specific details. For instance,
although examples refer to executing an attenuation level based
association procedure in a powerline communication (PLC) network
(e.g., a HomePlug.RTM. Green PHY network), embodiments are not so
limited. In other embodiments, the operations described herein for
signal level attenuation characterization can be executed in other
suitable shared communication networks (e.g., a HomePlug AV
network, a Multimedia over Coax Alliance (MoCA) network, an
Ethernet over Coax (EoC), wireless local area networks (WLAN) such
as IEEE 802.11 networks, etc.). In other instances, well-known
instruction instances, protocols, structures, and techniques have
not been shown in detail in order not to obfuscate the
description.
[0013] Communication between an electric vehicle and a charging
station may be accomplished using a power cable that is used to
connect the electric vehicle to the charging station in a charging
facility. However, using the power cable to exchange communications
can result in signal leakage because other charging stations (of
the charging facility) that are not physically connected to the
electric vehicle may also receive (e.g., via RF coupling) the
signal intended for the charging station that is physically
connected to the electric vehicle. Accordingly, the electric
vehicle may detect (e.g., receive response messages from) many
charging stations in the charging facility and may need to identify
and associate with one of the charging stations to which it is
physically connected and from which it should receive electric
power.
[0014] In some embodiments, the electric vehicle and one or more
charging stations in the charging facility can be configured to
implement an association procedure between the electric vehicle and
the appropriate charging station. In accordance with this
association procedure, the electric vehicle can use multi-network
broadcast communications to broadcast one or more service matching
messages to the charging stations in the charging facility. The
electric vehicle can receive attenuation information (e.g., a
measured signal level) from one or more of the charging stations in
response to the broadcast service matching messages. The electric
vehicle can analyze the attenuation information received from the
charging stations to identify which charging station should provide
electric power to the electric vehicle (i.e., to identify a
"matched" charging station for the electric vehicle). The electric
vehicle can then associate with (and receive electric power from)
the matched charging station. Such an association procedure that
uses attenuation information (or detected signal level information)
received from multiple charging stations to automatically detect
the charging station to which the electric vehicle is physically
connected can simplify the electric vehicle charging process for a
user. Furthermore, in some embodiments, the electric vehicle and
the charging stations can employ a secure association procedure by
signing messages exchanged between the electric vehicle and the
charging stations with their respective encryption keys. Using the
secure association procedure can enable the electric vehicle and
the charging stations to validate each received communication. This
can ensure that malicious electric vehicles that generate strong
signals are not matched (and do not receive service) instead of a
legitimate electric vehicle. Executing the secure association
procedure where each communication is numbered, then signed and/or
encrypted can minimize replay attacks and transmission/reception of
spoofed messages.
[0015] FIG. 1 is an example conceptual diagram illustrating an
association procedure between an electric vehicle and one or more
charging stations in a charging facility 100. In FIG. 1, the
charging facility 100 comprises an electric vehicle 102 and
charging stations 106, 108, and 110. The electric vehicle 102
comprises a communication unit 104. The communication unit 104
comprises an association unit 112. The charging station 106 also
comprises a communication unit 114. The communication unit 114
comprises an association unit 116. It is noted that although not
depicted in FIG. 1, the charging stations 108 and 110 can each
comprise a communication unit and an association unit. The
functionality for executing the association procedure and
identifying the matched charging station (e.g., the communication
unit 104 or the communication unit 114) can be implemented on a
suitable circuit board, such as an integrated circuit (IC), a
system-on-a-chip (SoC), an application specific IC (ASIC), etc. In
some embodiments, the functionality for executing the association
procedure can be implemented across multiple chips on a circuit
board, across multiple circuit boards, etc. The communication unit
104 can implement protocols and functionality to enable the
electric vehicle 102 to communicate with one or more of the
charging stations 106, 108, and 110 in the charging facility 100.
Likewise, the communication unit 114 (of the charging station 106)
can implement protocols and functionality to enable the charging
station 106 to communicate with the electric vehicle 102 (and in
some embodiments, with the other charging stations 108 and 110). In
some embodiments, the charging facility 100 can be a shared
communication network (e.g., a powerline communication (PLC)
network, such as a HomePlug.RTM. Green PHY network). In other
embodiments, the charging facility 100 can be other suitable types
of networks (e.g., Ethernet over Coax (EoC), wireless local area
networks (WLAN), such as IEEE 802.11 networks, etc.). The charging
stations 106, 108, and 110 can be communicatively coupled using
wireless communication protocols (e.g., WLAN, Bluetooth, etc.) or
using wired communication protocols (e.g., PLC, Ethernet, etc.). It
is also noted that in some embodiments, the association procedure
may be implemented using messages and the framework of the Signal
Level Attenuation Characterization (SLAC) procedure of the
HomePlug.RTM. Green PHY specification to enable association between
the electric vehicle 102 and one of the charging stations of the
charging facility 100. FIGS. 1-5 will be described below using
examples of the SLAC procedure of the HomePlug Green PHY
specification. However, in other embodiments, the association
procedure may be implemented using messages and the framework of
other suitable communication technologies.
[0016] In some embodiments, a circuit board that implements the
association functionality may be used as part of the electric
vehicle and also as part of the charging station. Accordingly,
prior to initiating the association procedure, the electric vehicle
102 can be configured in a slave/client operating mode while the
charging stations 106, 108, and 110 can be configured in a master
operating mode. For example, a Green PHY module (e.g., the
communication unit 104) of the electric vehicle 102 can be
configured to not be a central coordinator of a network. In this
example, a Higher Layer Entity (HLE) of the electric vehicle 102
can provide a suitable message (e.g., an APCM_SET_CCo.REQ
primitive) to configure the Green PHY module of the electric
vehicle 102 to not be a central coordinator of a network that the
electric vehicle joins and to, instead, be a client/slave of the
network. The Green PHY module of the electric vehicle 102 can
provide a confirmation message (e.g., an APCM_SET_CCo.CNF message)
to the HLE of the electric vehicle 102 to indicate that it has been
successfully configured in the client operating mode. The electric
vehicle 102 may also be configured to initiate the association
procedure and to be a transmitter of the service matching messages.
For example, the HLE of the electric vehicle 102 can provide a
suitable message (e.g., an APCM_CONF_SLAC.REQ message) to configure
the Green PHY module (e.g. the communication unit 104) of the
electric vehicle 102 to execute those operations of the association
procedure that are associated with a transmitter of the service
matching messages. The Green PHY module of the electric vehicle 102
can provide a confirmation message (e.g., an APCM_CONF_SLAC.CNF
message) to the HLE of the electric vehicle 102 to indicate
successful configuration. Likewise, a Green PHY module of the
charging station 106 (e.g., the communication unit 114 of the
charging station 106) can be configured to be a central coordinator
of a network. In this example, the HLE of the charging station 106
can provide a suitable message to configure the Green PHY module of
the charging station 106 to be the central coordinator of a network
that the charging station 106 joins. The HLE of the charging
station 106 can provide a suitable message to configure the Green
PHY module of the charging station 106 to execute those operations
of the association procedure that are associated with a receiver of
the service matching messages. It is noted that in other
embodiments, other suitable techniques and communication protocols
can be implemented to configure the electric vehicle 102 and the
charging station 106 in the appropriate operating mode.
[0017] It is noted, however, that the configuration of the electric
vehicle 102 and the charging stations 106, 108, and 110 may be
implementation dependent. In one embodiment, the electric vehicle
102 and the charging stations 106, 108, and 110 may be permanently
configured (e.g., in the client operating mode or the master
operating mode) during a manufacturing process or before
deployment. In another embodiment, the electric vehicle 102 and the
charging stations 106, 108, and 110 may be configured on-the-fly,
before the association procedure is initiated. In another
embodiment, the charging stations 106, 108, and 110 may be
permanently configured during the manufacturing process; while the
electric vehicle 102 may be dynamically configured before the
association procedure is initiated, or vice versa. In another
embodiment, the Green PHY modules in the electric vehicle 102 and
the charging stations 106, 108, and 110 may automatically detect
whether they are part of an electric vehicle or a charging station
and may automatically configure themselves accordingly. For
example, the configuration of the charging station 106 may be
determined depending on whether an electric vehicle 102 is
associated with the charging station 106.
[0018] The electric vehicle 102 can execute the association
procedure with the charging stations 106, 108, and 110 to associate
with and receive electric power from one of the charging stations
106, 108, and 110 based on attenuation information (or signal level
information) received from one or more of the charging stations
106, 108, and 110, as will be further described below in stages
A-F.
[0019] At stage A, the association unit 112 of the electric vehicle
102 transmits a request for association parameters to establish a
communication link with one of the charging stations 106, 108, and
110. In some embodiments, the electric vehicle 102 (e.g., the
higher level entity (HLE) of the electric vehicle) can determine
that the electric vehicle 102 is connected to a charging station
using a charging cordset. Accordingly, the association unit 112 can
initiate the association procedure by broadcasting the request for
communication parameters ("communication parameters request
message"). After broadcasting the communication parameters request
message, the association unit 112 can also start a communication
parameters timer to track the reception of the communication
parameters from one or more of the charging stations 106, 108, and
110. As part of the communication parameters request message, the
association unit 112 may also indicate whether or not it supports a
secure association procedure. In accordance with the secure
association procedure, the electric vehicle 102 and the charging
stations 106, 108, and 110 can sign/encrypt all subsequent
communications for the recipient to accept the communications.
[0020] At stage B, the association unit 112 of the electric vehicle
102 receives the communication parameters from one or more of the
charging stations 106, 108, and 110. The charging stations 106,
108, and 110 can use the communication parameters to control the
behavior of the electric vehicle 102. In response to receiving the
communication parameters request message, each of the charging
stations 106, 108, and 110 can transmit a communication parameters
response message including the communication parameters associated
with the charging station. Each of the charging stations 106, 108,
and 110 can also indicate, in their respective communication
parameters response message, whether or not the charging station
supports the secure association procedure. In some embodiments, the
charging stations 106, 108, and 110 may also attempt to negotiate
what type of security mechanisms should be employed. For each of
the charging stations 106, 108, and 110, the communication
parameters can include a number of service matching messages that
should be transmitted to the charging station and other suitable
parameters, as will be further discussed below in FIGS. 2-5. Based
on receiving the communication parameters, the association unit 112
of the electric vehicle 102 can also determine whether to execute
the secure association procedure with the charging stations 106,
108, and 110. If the association unit 112 determines that the
secure association procedure should be executed with the charging
stations 106, 108, and 110, then prior to transmitting the service
matching messages (described below in stage C), the association
unit 112 can transmit its security information (e.g., public key
certificates) to the charging stations 106, 108, and 110 and can
receive security information associated with the charging stations
106, 108, and 110. If the secure association procedure is executed,
subsequent communications between the electric vehicle 102 and the
charging stations 106, 108, and 110 (and between the charging
stations 106, 108, and 110 and the electric vehicle 102) can be
signed with the appropriate security information.
[0021] At stage C, the association unit 112 transmits one or more
service matching messages to the charging stations 106, 108, and
110 based on the received communication parameters. For example,
based on the communication parameters received from the charging
stations 106, 108, and 110, the association unit 112 can determine
how many service matching messages should be broadcast. The
association unit 112 can then broadcast the determined number of
service matching messages (also referred to as multi-network sounds
or M-sounds) using multi-network broadcast (MNBC) communication. As
discussed above, if the association unit 112 determines that the
secure association procedure should be executed with the charging
stations 106, 108, and 110, the association unit 112 can sign the
service matching messages prior to broadcasting the service
matching messages.
[0022] At stage D, the charging stations 106, 108, and 110
determine their respective attenuation information (or signal level
information) based, at least in part, on the received service
matching messages and provide the attenuation information to the
electric vehicle 102. For example, the association unit 116 of the
charging station 106 can determine the measured signal strength of
the received service matching messages at different carrier
frequencies and can notify the electric vehicle of the measured
signal strength, as will be further described below with reference
to FIG. 4. After all the service matching messages are received or
after a predetermined time interval elapses, the charging stations
106, 108, and 110 can transmit their respective attenuation
information to the electric vehicle 102. It is noted that if the
secure association procedure is executed, each of the charging
stations 106, 108, and 110 can validate the received service
matching messages prior to determining their respective attenuation
information. Additionally, the charging stations 106, 108, and 110
can sign the attenuation information using their respective
security information (e.g., signing key) prior to transmitting the
attenuation information to the electric vehicle 102.
[0023] At stage E, the association unit 112 of the electric vehicle
102 determines a charging station ("matched charging station") with
which the electric vehicle should associate based on the
attenuation information received from the charging stations 106,
108, and 110. The association unit 112 can analyze the received
attenuation information and can select one of the charging stations
(e.g., the charging station 106) as the matched charging station.
The matched charging station is typically the charging station 106
to which the electric vehicle 102 is physical connected and from
which the electric vehicle 102 will receive electric power. For
example, the charging station 106 that is associated with the
lowest attenuation level (or highest signal level) can be selected
as the matched charging station. The association unit 112 can
transmit a match notification message to the matched charging
station 106 to notify the matched charging station 106 of the
results of the association procedure.
[0024] At stage F, the communication unit 104 establishes the
communication link 118 with the matched charging station 106 and
receives power from the matched charging station 106. In response
to receiving the match notification message from the electric
vehicle 102, the matched charging station 106 (e.g., the
association unit 116) can transmit a match confirmation message to
the electric vehicle 102. The match confirmation message can
include a network identifier (NID) of a network associated with the
matched charging station 106, a network membership key (NMK) of the
network associated with the matched charging station 106, a MAC
address of the matched charging station 106, etc. Additionally, the
matched charging station 106 can sign all or part of the match
confirmation message using its security information (e.g., signing
key) and encrypt all or part of the match confirmation message
(e.g., NID and NMK) using the security information (e.g., public
encryption key) of the electric vehicle 102 prior to transmitting
all or part of the match confirmation message to the electric
vehicle 102. The electric vehicle 102 and the matched charging
station 106 can each configure themselves using the NID and the NMK
of the network associated with the matched charging station 106.
The electric vehicle 102 and the matched charging station 106 can
form an AV logical network (AVLN). After the matched charging
station 106 (e.g., an authentication unit of the matched charging
station 106) successfully authenticates and authorizes the electric
vehicle 102, the electric vehicle 102 can receive electric power
from the matched charging station 106 (e.g., from a charging unit
of the matched charging station 106).
[0025] FIG. 2 and FIG. 3 depict a flow diagram ("flow") 200
illustrating example operations of a network device executing an
association procedure for establishing a communication link with a
service provider of a communication network. The flow begins at
block 202 in FIG. 2. It is noted that FIGS. 2-3 will be described
below using example messages and framework of the SLAC procedure of
the HomePlug Green PHY specification.
[0026] At block 202, a client network device determines to
establish a communication link with one of a plurality of service
providers. In some embodiments, the client network device can be a
plug-in electric vehicle (PEV); while the service providers can
each be an electric vehicle supply equipment (EVSE) also referred
to as a charging station. With reference to the example of FIG. 1,
the association unit 112 of the electric vehicle 102 can determine
that the electric vehicle 102 is connected to one of the charging
stations 106, 108, and 110 using a charging cordset. Accordingly,
the association unit 112 can configure the electric vehicle 102 in
a client operating mode and can initiate the association procedure
with the charging stations 106, 108, and 110. The flow continues at
block 204.
[0027] At block 204, a communication parameters request message for
communication parameters is transmitted to the service providers
and a communication parameters timer is initiated. With reference
to the example of FIG. 1, the association unit 112 of the electric
vehicle 102 can broadcast the communication parameters request
message (e.g., a CM_SLAC_PARM.REQ message) to receive communication
parameters associated with the charging stations 106, 108, and 110.
In some embodiments, the communication parameters request message
can be a multi-network broadcast (MNBC) message. As will be further
described below, the association unit 112 can use the communication
parameters (received from the charging stations 106, 108, and 110)
to execute the association procedure with the charging stations
106, 108, and 110. In some embodiments, the communication
parameters request message can comprise an identifier of the
electric vehicle 102, an indication of whether the electric vehicle
supports a secure association procedure, etc. After broadcasting
the communication parameters request message, the association unit
112 can also start the communication parameters timer to track the
reception of the communication parameters from one or more charging
stations 106, 108, and 110. The value in the communication
parameters timer can indicate the amount of time for which the
association unit 112 will wait to receive the communication
parameters from one or more of the charging stations 106, 108, and
110. The flow continues at block 206.
[0028] At block 206, it is determined whether the communication
parameters timer has elapsed. With reference to the example of FIG.
1, the association unit 112 can determine whether the communication
parameters timer has elapsed. As discussed above, the communication
parameters timer can indicate a maximum time interval for which the
association unit 112 (of the electric vehicle 102) will wait to
receive the communication parameters from the charging stations
106, 108, and 110. If it is determined that the communication
parameters timer has elapsed, the flow continues at block 208.
Otherwise, the flow loops back to block 206, where the association
unit 112 continues to determine whether the communication
parameters timer has elapsed.
[0029] At block 208, it is determined whether the communication
parameters were received at the client network device. The flow 200
moves from block 206 to block 208 in response to determining that
the communication parameters timer has elapsed. With reference to
the example of FIG. 1, the association unit 112 of the electric
vehicle 102 can determine whether a communication parameters
response message (e.g., a CM_SLAC_PARM.CNF message) including the
communication parameters was received from at least one of the
charging stations 106, 108, and 110. If it is determined that the
communication parameters were received from at least one of the
charging stations 106, 108, and 110, the flow continues at block
210. Otherwise, if it is determined that the communication
parameters were not received at the network device (after the
communication parameters timer has elapsed), the flow ends. It is
noted, however, that in other embodiments, if it is determined that
the communication parameters were not received at the network
device (after the communication parameters timer has elapsed), the
association unit 112 can restart the association procedure by
rebroadcasting the communication parameters request message to all
the charging stations 106, 108, and 110.
[0030] At block 210, it is determined, based on the received
communication parameters, whether operations for the secure
association procedure should be executed. With reference to the
example of FIG. 1, the association unit 112 can receive the
communication parameters response message (e.g., a CM_SLAC_PARM.CNF
message) including the communication parameters from the charging
stations 106, 108, and 110. The communication parameters response
message (e.g., received from the charging station 106) can comprise
an identifier (e.g., a MAC address) of the charging station 106, an
identifier of the electric vehicle 102, an indication of whether
the charging station 106 supports the secure association procedure,
and other suitable information. The communication parameters
associated with the charging station 106 can comprise a number of
service matching messages that should be transmitted to the
charging station 106, a maximum time interval within which the
service matching messages should be transmitted to the charging
station 106, etc. It is noted that each of the charging stations
106, 108, and 110 may transmit a different set of communication
parameters to the electric vehicle 102. The association unit 112
can consolidate the received communication parameters and execute
the association procedure with the charging stations 106, 108, and
110 in accordance with the consolidated communication
parameters.
[0031] With reference to the example of FIG. 1, the association
unit 112 can determine (based on the received communication
parameters response messages) whether the charging stations 106,
108, and 110 support the secure association procedure. In some
embodiments, if the electric vehicle 102 supports the secure
association procedure, the electric vehicle 102 can support one or
more encryption protocols such as digital signature algorithm (DSA)
with 256-bit secure hash algorithm (SHA-256), Rivest-Shamir-Adleman
(RSA) algorithm, 128-bit advanced encryption standard (AES-128)
algorithm, in cipher block chaining (CBC) mode, elliptic curve
digital signature algorithm (ECDSA), ES-DH, AES-256, etc. If the
electric vehicle 102 and the charging stations 106, 108, and 110
support the encryption protocols (and hence the secure association
procedure), the association unit 112 can determine that the secure
association procedure should be executed. In some embodiments, if
even one of the charging stations does not support the secure
association procedure, the association unit 112 can determine that
the secure association procedure should not be executed. If it is
determined that operations for the secure association procedure
should be executed, the flow continues at block 212. Otherwise, the
flow continues at block 214 in FIG. 3.
[0032] At block 212, in response to determining that operations for
the secure association procedure should be executed, security
information associated with the client network device is provided
to the service providers. With reference to the example of FIG. 1,
if the association unit 112 determines, based on the received
communication parameters response messages (e.g., the
CM_SLAC_PARM.CNF messages) that the secure association procedure
should be executed, the association unit 112 can transmit security
information associated with the electric vehicle 102 (e.g., in a
CM_PKCS_CERT.IND message) to the charging stations 106, 108, and
110. In some embodiments, the security information associated with
the electric vehicle 102 can comprise a public key certificate
(associated with the electric vehicle 102) that can be used for
transport layer security. The security information can also
indicate the length of the public key certificate, a cipher suite
of the public key certificate, an address (e.g., a MAC address) of
the electric vehicle 102, etc. In some embodiments, the public key
certificate associated with the electric vehicle 102 can be an
X.509v3 certificate. The public key certificate can be provided to
the charging stations 106, 108, and 110 as a signed Cryptographic
Message Syntax (CMS) message (e.g., in accordance with IETF RFC
5652) with null content and attached certificate list, and
certificate revocation lists (CRLs). The public key certificate
associated with the electric vehicle 102 may be signed by a
certificate authority (CA) authorized to issue electric vehicle
certificates. The public key certificate associated with the
electric vehicle 102 may have one or more attributes that identify
the certificate holder (i.e., the electric vehicle 102) as a
legitimate electric vehicle. Furthermore, the certificate authority
that signed the electric vehicle's certificate may be authorized to
vouch for the electric vehicle's identity. In some embodiments, the
security information associated with the electric vehicle 102 can
be transmitted a predetermined number of times. In another
embodiment, the security information associated with the electric
vehicle 102 can be transmitted until the electric vehicle 102
(e.g., the association unit 112) receives an acknowledgement
message from the charging stations 106, 108, and 110 (e.g., all the
charging stations that responded with their communication
parameters). Furthermore, in some embodiments, the security
information associated with the electric vehicle 102 can be
transmitted using multi-network broadcast (MNBC) communication.
[0033] In some embodiments, in addition to transmitting the
security information associated with the electric vehicle 102 to
the charging stations 106, 108, and 110, the electric vehicle 102
(e.g., the association unit 112) may also receive security
information (e.g., public key certificates) associated with each of
the charging stations 106, 108, and 110. All public key
certificates received by the electric vehicle 102 can be validated
(e.g., in accordance with Section 9 of ZigBee-11185r05) before
associating the public key with the identity and attributes of the
certificate. For example, the electric vehicle 102 can verify the
attributes indicated in the public key certificate to validate the
charging station 106 that transmitted the public key certificate.
The electric vehicle 102 can keep track of public keys for the root
CAs that are authorized to vouch for the legitimacy of the charging
stations 106, 108, and 110. After the security information is
exchanged, subsequent messages transmitted from the electric
vehicle 102 to the charging stations 106, 108, and 110 may be
signed and/or encrypted. In some embodiments, to sign and encrypt
the messages, the electric vehicle 102 (e.g., the association unit
112) may sign the content first and then encrypt the signed
content. In other words, the outer content type may be encrypted
data, and the inner content type may be the signed data. The flow
continues at block 214 in FIG. 3.
[0034] At block 214, one or more service matching messages are
broadcast to the service providers based, at least in part, on the
received communication parameters. For example, the association
unit 112 can analyze the received communication parameters to
determine how many service matching messages should be broadcast.
For example, the communication parameters received from the
charging stations 106, 108, and 110 can indicate that 5, 8, and 10
service matching messages should be transmitted to the charging
stations 106, 108, and 110 respectively. Accordingly, the
association unit 112 may determine to broadcast 10 service matching
messages. In some embodiments, prior to transmitting the service
matching messages, the association unit 112 can transmit an
association initiation message (e.g., a CM_START_ATTEN_CHAR.IND
message) to notify the charging stations 106, 108, and 110 that the
association procedure will start. The association initiation
message may be a multi-network broadcast message. In some
embodiments, the association unit 112 may transmit the association
initiation message a predetermined number of times (e.g., three
times) to ensure that all the charging stations 106, 108, and 110
receive the association initiation message. If the association unit
112 determined that the secure association procedure should be
executed, the association unit 112 can encrypt the association
initiation messages prior to transmitting the association
initiation messages. Additionally, the association initiation
messages can also indicate the communication parameters in
accordance with which the association procedure will be executed.
For example, the association initiation messages can indicate a
number of service matching messages that will be transmitted (e.g.,
10 service matching messages with reference to the above example),
a maximum time interval during which the service matching messages
will be transmitted, an identifier of the electric vehicle, to whom
the attenuation information should be transmitted, etc.
[0035] The association unit 112 can then broadcast the service
matching messages (e.g., CM_MNBC_SOUND.IND messages) to the
charging stations 106, 108, and 110. In some embodiments, the
service matching messages can be multi-network broadcast messages.
As described above, the number of service matching messages that
are transmitted may be based on the communication parameters
received from the charging stations 106, 108, and 110. The service
matching messages can comprise an identifier (e.g., a vehicle
identifier (VIN)) of the electric vehicle, a number of remaining
service matching messages that will be transmitted, and other
suitable information. It is noted that if the electric vehicle 102
is configured to execute the secure association procedure with the
charging stations 106, 108, and 110, the association unit 112 can
encrypt/sign the service matching messages with the public key
signature of the electric vehicle 102, prior to transmitting the
service matching messages. The flow continues at block 216.
[0036] At block 216, attenuation information is received from one
or more service providers in response to the broadcasting the
service matching messages to the service providers. In some
embodiments, after the association unit 112 transmits all the
service matching messages to the charging stations 106, 108, and
110 (and/or after the time interval for transmitting the service
matching messages elapses), the association unit 112 can start
another timer for receiving the attenuation information from the
charging stations 106, 108, and 110. With reference to the example
of FIG. 1, the association unit 112 can receive attenuation
information (e.g., in a CM_ATTEN_CHAR.IND message) from one or more
charging stations 106, 108, and 110. Operations of the charging
stations 106, 108, and 110 for determining the attenuation
information will further be described below with reference to FIGS.
4-5. When the association unit 112 receives the attenuation
information from a charging station (e.g., the charging station
106) in an appropriate message, the electric vehicle 102 can verify
the authenticity of the received message by determining whether a
charging station identifier received with the attenuation
information matches a previously received charging station
identifier. If the electric vehicle 102 is configured to execute
the secure association procedure with the charging station 106, the
association unit 112 can also verify the signature on the received
message. The association unit 112 can discard the message including
the received attenuation information if the charging station
identifier does not match a previously received charging station
identifier or if the signature indicates that the message was not
from an authorized charging station or was a replay.
[0037] In some embodiments, in response to receiving the
attenuation information from the charging station 106, the
association unit 112 may transmit an acknowledgement message (e.g.,
a CM_ATTEN_CHAR.RSP message) to the charging station 106. The
acknowledgement message may be signed/encrypted if the electric
vehicle 102 and the charging station 106 are configured to execute
the secure association procedure. In some embodiments, as will be
further described below, the association unit 112 can select the
matched charging station after the time interval for receiving the
attenuation information elapses. If (after the time interval
elapses) the association unit 112 has not received the attenuation
information from any of the charging stations 106, 108, and 110,
the association unit 112 can restart the association procedure by
rebroadcasting the communication parameters request message. The
flow continues at block 218.
[0038] At block 218, the client network device analyses the
received attenuation information and selects one of the service
providers with which to associate. With reference to the example of
FIG. 1, the association unit 112 can analyze the attenuation
information messages (e.g., the CM_ATTN_CHAR.IND message) received
from one or more charging stations 106, 108, and 110. Based on this
analysis, the association unit 112 can determine the charging
station ("matched charging station") to which the electric vehicle
102 is connected though the charging cordset. In using the
attenuation information received from the charging stations 106,
108, and 110 to identify the matched charging station, it is
assumed that the charging station 106 that is directly connected to
the electric vehicle 102 (e.g., via the charging cordset) will
receive the service matching messages from the electric vehicle 102
with minimal attenuation. For any other charging station 108, 110
(that is not directly connected to the electric vehicle 102) to
receive the service matching messages, the service matching
messages would have to pass through multiple open contacts (e.g.,
switches) and/or PLC pass band (RF) coupling, which can
significantly reduce the signal strength (i.e., increase the
attenuation) measured by the other charging stations 108, 110. The
association unit 112 of the electric vehicle 102 can exploit the
inherent asymmetry in signal strength at different charging
stations to associate (match) the electric vehicle with the
charging station to which it is physically connected through the
charging cordset. In other words, the charging station 106 that is
directly connected to the electric vehicle 102 will detect the
highest signal level for a received signal (or the lowest
attenuation level for a received signal). Accordingly, in some
embodiments, the matched charging station can be selected as one of
the charging stations 106 that is associated with the lowest
attenuation level (or the highest signal level). In some
embodiments, the electric vehicle 102 can determine the matched
charging station based on attenuation information received from one
or more charging stations 106, 108, and 110 and based on the
electric vehicle's local signal level measurements of transmissions
received from the charging stations 106, 108, and 110. The
association unit 112 of the electric vehicle 102 can combine the
attenuation information received from the charging stations 106,
108, and 110 with the attenuation information measured by the
electric vehicle 102 to make the proper association decision (i.e.,
to determine the matched charging station). The flow continues at
block 220.
[0039] At block 220, the selected service provider is notified to
associate with the client network device. With reference to the
example of FIG. 1, the association unit 112 of the electric vehicle
102 can transmit a match notification message (e.g., a
CM_SLAC_MATCH.REQ message) to notify the charging station 106 that
the charging station 106 was identified as the matched charging
station for the electric vehicle 102 and that the electric vehicle
102 is connected to the matched charging station 106. The match
notification message may or may not be signed/encrypted with the
electric vehicle's encryption key depending on whether the secure
association procedure was executed. The match notification message
can comprise an identifier (e.g., VIN) of the electric vehicle 102,
a MAC address of the electric vehicle 102, an identifier of the
matched charging station 106, a MAC address of the matched charging
station 106, etc. In addition, the association unit 112 can also
transmit the match notification message as a request for the
network connection parameters (e.g., a network identifier (NID), a
network membership key (NMK), etc.) from the matched charging
station 106. The association unit 112 may re-transmit the match
notification message a predetermined number of times if a match
confirmation message is not received within a predetermined time
interval. In some embodiments, the match notification message can
be a multi-network broadcast message. The flow continues at block
222.
[0040] At block 222, the client network device associates with the
selected service provider and receives the service from the
selected service provider. With reference to the example of FIG. 1,
the association unit 112 can receive the network connection
parameters (e.g., the NID and the NMK) from the matched charging
station 106, as will be further described below in FIG. 5. The
association unit 112 can then configure the electric vehicle 102
using the received network connection parameters. Likewise, the
matched charging station 106 can also be configured (as will be
described below in FIG. 5) using the network connection parameters.
The electric vehicle 102 and the matched charging station 106 can
then form an AVLN using the common NID and the common NMK. It is
noted that if the electric vehicle 102 and the matched charging
station 106 are configured to execute the secure association
procedure, then in response to receiving the match confirmation
message including the network connection parameters, the
association unit 112 can verify the charging station identifier and
the public key signature associated with the matched charging
station 106. The electric vehicle 102 can associate with the
matched charging station 106 if the charging station identifier and
the public key signature are verified. From block 222, the flow
ends.
[0041] FIG. 4 and FIG. 5 depict a flow diagram 400 illustrating
example operations of a service provider executing an association
procedure with a client network device. The flow 400 begins at
block 402 in FIG. 4. It is noted that FIGS. 4-5 will be described
below using example messages and framework of the SLAC procedure of
the HomePlug Green PHY specification.
[0042] At block 402, a service provider receives a communication
parameters request message from a client network device. In some
embodiments, the client network device can be a plug-in electric
vehicle (PEV); while the service provider can be an electric
vehicle supply equipment (EVSE) also referred to as a charging
station. With reference to the example of FIG. 1, in some
embodiments, prior to receiving the communication parameters
request message, the association unit 116 of the charging station
106 may determine that the charging station 106 is connected to an
electric vehicle 102 using a charging cordset. Accordingly, the
association unit 116 can configure the charging station 106 in a
master operating mode and can configure the charging station 106 to
support association procedures with the electric vehicle 102. As
described above with reference to FIG. 2, in addition to a request
for communication parameters associated with the charging station,
the communication parameters request message can comprise an
identifier of the electric vehicle 102, an indication of whether
the electric vehicle 102 supports a secure association procedure,
etc. The flow continues at block 404.
[0043] At block 404, the communication parameters associated with
the service provider are transmitted to the client network device.
With reference to the example of FIG. 1, the association unit 116
of the charging station 106 can transmit the communication
parameters associated with the charging station 106 to the electric
vehicle 102. In one embodiment, the association unit 116 can
transmit a communication parameters response message (e.g., a
CM_SLAC_PARM.CNF message) including the communication parameters
associated with the charging station 106. The communication
parameters response message can comprise an identifier of the
charging station 106, the identifier of the electric vehicle 102,
an indication of whether the charging station 106 supports the
secure association procedure, etc. The communication parameters
response message can also comprise the communication parameters
including a number of service matching messages that should be
transmitted to the charging station 106, a maximum time interval
within which the service matching messages should be transmitted to
the charging station 106, etc. In some embodiments, the number of
service matching messages requested by the charging station 106 may
be based on the network configuration and the position of the
charging station 106 relative to other charging stations (and
network devices). For example, if the charging station 106 is
operating in a noisy environment, the association unit 116 (of the
charging station 106) may indicate that a large number of service
matching messages should be transmitted to the charging station
106. Alternately, if the charging station 106 is operating in a
relatively noise-free environment, the association unit 116 may
indicate that a smaller number of service matching messages should
be transmitted to the charging station 106. Receiving a larger
number of service matching messages in the noisy environment can
help the association unit 116 average out the effect of noise on
the attenuation measurements. In some embodiments, the number of
service matching messages requested by the charging station 106 may
be based on the number of electric vehicles that can be supported
(e.g., for charging) at the charging station 106. Thus, if the
charging station 106 is configured to support charging for multiple
electric vehicles, the charging station 106 may require a larger
number of service matching messages to determine whether the
electric vehicle 102 is connected to the charging station and (if
so) to which charging slot the electric vehicle 102 is connected.
For example, if the charging station 106 comprises two charging
ports (that can be used to charge two electric vehicles), the
association unit 116 may indicate that the electric vehicle 102
should broadcast, for example, 30 service matching messages to the
charging station 106. In this example, the association unit 116 can
then utilize the first 15 service matching messages to determine
whether the electric vehicle 102 is connected to the first charging
port of the charging station 106 and can utilize the remaining 15
service matching messages to determine whether the electric vehicle
102 is connected to the second charging port of the charging
station 106. In addition, the association unit 116 can indicate (in
the communication parameters response message) whether the charging
station 106 supports the secure association procedure. In some
embodiments, if the charging station 106 supports the secure
association procedure, the charging station 106 can support one or
more encryption protocols such as DSA with SHA-256, RSA, AES-128 in
CBC mode, ECDSA, ES-DH, AES-256, etc. In some embodiments, the
communication parameters response message including the
communication parameters can be transmitted using a multi-network
broadcast message. The flow continues at block 406.
[0044] At block 406, it is determined whether security information
associated with the client network device was received at the
service provider. As described above, as part of the communication
parameters request message, the electric vehicle 102 can indicate
whether it (i.e., the electric vehicle 102) supports the secure
association procedure. Likewise, as part of the communication
parameters response message, the association unit 116 can indicate
whether the charging station 106 supports the secure association
procedure. If the electric vehicle 102 and all the charging
stations 106, 108, and 110 (that communicate with the electric
vehicle 102) support the secure association procedure, the electric
vehicle 102 can transmit its security information to the charging
stations 106, 108, and 110. For example, the association unit 116
may receive (from the electric vehicle 102) a public key
certificate associated with the electric vehicle 102, as described
above in block 210 of FIG. 2. If it is determined that the security
information associated with the client network device was received,
the flow continues at block 408. Otherwise, if it is determined
that the security information associated with the client network
device was not received, the service provider determines to execute
an unsecure association procedure with the client network device,
and the flow continues at block 410.
[0045] At block 408, the service provider determines to execute a
secure association procedure with the client network device. In
response to determining that the security information (e.g., a
public key certificate) was received from the electric vehicle 102,
the association unit 116 of the charging station 106 can determine
to execute the secure association procedure with the electric
vehicle 102. In some embodiments, the association unit 116 can
validate the public key certificate received from the electric
vehicle 102 (e.g., in accordance with RFC 5258) before associating
the public key with the identity and attributes of the certificate.
For example, the association unit 116 can verify the attributes
indicated in the received public key certificate to validate the
authenticity of the electric vehicle 102 that transmitted the
public key certificate. After the electric vehicle 102 is
validated, the association unit 116 can store the received public
key certificate associated with the electric vehicle 102 for
verifying signed/encrypted communications (e.g., service matching
messages) subsequently received from the electric vehicle 102. The
charging station 106 can also keep track of public keys for the
root CAs that are authorized to vouch for the legitimacy of the
electric vehicle 102.
[0046] In some embodiments, in response to determining to execute
the secure association procedure with the electric vehicle 102, the
association unit 116 (of the charging station 106) can also
transmit security information associated with the charging station
106 (e.g., in a CM_PKCS_CERT.IND message) to the electric vehicle
102. In some embodiments, the security information of the charging
station 106 can comprise a public key certificate (associated with
the charging station 106) that can be used for transport layer
security. The security information can also indicate the length of
the public key certificate, a cipher suite of the public key
certificate, an address (e.g., a MAC address) of the charging
station 106, etc. In some embodiments, the public key certificate
associated with the charging station 106 can be an X.509v3
certificate. The public key certificate can be provided to the
electric vehicle 102 as a signed CMS message (e.g., in accordance
with RFC 5652) with null content and attached certificate list, and
CRLs. The public key certificate associated with the charging
station 106 may be signed by a CA authorized to issue charging
station certificates. The public key certificate associated with
the charging station 106 may have one or more attributes that
identify the certificate holder (i.e., the charging station 106) as
a legitimate charging station. Furthermore, the certificate
authority that signed the charging station's certificate may be
authorized to vouch for the charging station's identity. In some
embodiments, the security information associated with the charging
station 106 can be transmitted a predetermined number of times. In
another embodiment, the security information associated with the
charging station 106 can be transmitted until the charging station
106 (e.g., the association unit 116) receives an acknowledgement
message (e.g., a CM_PKCS_CERT.RSP message) from the electric
vehicle 102. Furthermore, in some embodiments, the security
information associated with the charging station 106 can be
transmitted using multi-network broadcast (MNBC) communication. In
some embodiments, if the security information associated with the
charging station 106 cannot be transmitted in a single message
(e.g., because the length of the message is greater than the
maximum permissible message length), the message can be fragmented.
The flow continues at block 410.
[0047] At block 410, a notification indicating the start of the
association procedure ("association initiation message") is
received from the client network device. For example, the
association unit 116 of the charging station 106 can receive a
broadcast message (e.g., a MNBC message) indicating that the
association procedure will begin. In addition, the association
initiation message (e.g., a CM_START_ATTEN_CHAR.IND message) can
also comprise a time out value that indicates for how the electric
vehicle 102 will transmit the service matching messages. In
response to receiving the association initiation message, the
association unit 116 of the charging station 106 can start a timer
(that comprises the time out value received in the association
initiation message) and can wait to receive a predetermined number
of service matching messages from the electric vehicle 102. As will
be further described below, the association unit 116 can transmit
attenuation information associated with the charging station 106
after the timer elapses. It is also noted that the association
initiation message may or may not be signed by the electric vehicle
102 depending on whether or not the electric vehicle 102 and the
charging station 106 are configured to execute the secure
association procedure. The flow continues at block 412.
[0048] At block 412, one or more service matching messages are
received from the client network device. With reference to the
example of FIG. 1, in some embodiments, the association unit 116
can compare an electric vehicle identifier received in the service
matching message with a previously received electric vehicle
identifier (e.g., received in the communication parameters request
message) to determine whether the service matching message was
received from a legitimate electric vehicle and to minimize the
possibility of replay attacks by a rouge electric vehicle.
Additionally, the association unit 116 may also determine whether a
counter value of the received service matching message is less than
a counter value of a previously received service matching message.
In some embodiments, if the electric vehicle 102 and the charging
station 106 are configured to execute the secure association
procedure, the association unit 116 can determine whether the
electric vehicle's public key signature in each received service
matching message is valid to ensure that the service matching
message was received from a legitimate electric vehicle. The
association unit 116 can terminate the association procedure if the
received service matching messages are not valid. After the service
matching messages are received (and if the received service
matching messages are valid), the flow continues at block 414.
[0049] At block 414, attenuation information associated with the
service provider is determined based on the received service
matching messages. With reference to the example of FIG. 1, the
association unit 116 of the charging station 106 can process the
received service matching messages and can generate attenuation
information (or signal level attenuation information) based on the
received service matching messages. In some embodiments, the
attenuation information can comprise the attenuation profile
between the electric vehicle 102 (that transmitted the service
matching messages) and the charging station 106. In some
embodiments, a set of unmasked frequency carriers of the PLC
communication band can be divided into groups of a predetermined
number of frequency carriers (e.g., sixteen frequency carriers per
group), starting with the frequency carrier at the lowest
frequency. For each group of carriers, the average attenuation of
the group of carriers can be determined. It is noted that if a
group has less than the predetermined number of frequency carriers,
the average attenuation of the group can be determined based on the
available unmasked frequency carriers within the group. In some
embodiments, the attenuation profile associated with each service
matching message and each frequency carrier can be determined. The
average attenuation for a group of carriers and a predetermined
number of service matching messages can then be calculated based on
the attenuation profile associated with each service matching
message and each frequency carrier associated with the group. The
flow continues at block 416 in FIG. 5.
[0050] At block 416, the attenuation information associated with
the service provider is transmitted to the client network device.
In some embodiments, the association unit 116 can transmit the
attenuation information in a response message (e.g., a CM
_ATTEN_CHAR.IND message) to the electric vehicle 102 as soon as the
association unit 116 receives and processes a predetermined number
of service matching messages (indicated by the association unit 116
as part of the communication parameters). In another embodiment,
the association unit 116 can transmit the attenuation information
to the electric vehicle 102 after the last service matching message
(e.g., with a "0" count value) is received and analyzed. In another
embodiment, the association unit 116 can transmit the attenuation
information to the electric vehicle 102 after a predetermined time
interval allocated for receiving the service matching messages
elapses. The response message can comprise an address (e.g., a MAC
address) of the electric vehicle 102, an identifier (e.g., VIN) of
the electric vehicle 102, an identifier of the charging station
106, and the attenuation information (or signal level information)
associated with the charging station 106. In some embodiments, as
part of the attenuation information, the association unit 116 can
indicate the number of groups into which the frequency carriers
were divided and an average attenuation level associated with each
group of frequency carriers. In some embodiments, the response
message including the attenuation information may be a
multi-network broadcast message. It is noted that if the electric
vehicle 102 and the charging station 106 are configured to execute
the secure association procedure, the association unit 116 may sign
the response message including the attenuation information using
the public key certificate of the charging station 106. In some
embodiments, to ensure reliable reception of the attenuation
information at the electric vehicle 102, the association unit 116
may retransmit the response message including the attenuation
information to the electric vehicle 102 until an acknowledgement
message is received from the electric vehicle 102. The flow
continues at block 418.
[0051] At block 418, a notification is received from the client
network device indicating that the service provider was selected to
associate with the client network device. For example, the
association unit 116 of the charging station 106 can receive a
match notification message (described above in block 320 of FIG. 3)
that indicates that the electric vehicle 102 selected the charging
station 106 as the matched charging station and that the electric
vehicle wishes to associate with (and receive electric power from)
the charging station 106. The flow continues at block 420.
[0052] At block 420, the service provider determines whether to
associate with the client network device. For example, the
association unit 116 can determine whether the charging station 106
should associate with and establish a communication link with the
electric vehicle 102. In some embodiments, the association unit 116
(of the charging station 106) can receive attenuation information
associated with other charging stations 108 and 110 (with which the
electric vehicle 102 is communicating). The association unit 116
can analyze the attenuation information associated with the
charging stations 106, 108, and 110 and can identify the charging
station with which the electric vehicle 102 should associate
("expected matched charging station"). If the charging station 106
is the expected matched charging station, the association unit 116
can determine that the charging station 106 should associate with
the electric vehicle 102. If the charging station 106 is not the
expected matched charging station, the association unit 116 can
determine that the charging station 106 should not associate with
the electric vehicle 102. As another example, in response to
receiving the match notification message, the association unit 116
can determine whether the charging station 106 it is connected to
the electric vehicle 102 (e.g., via a charging cordset). If the
association unit 116 determines that the charging station 106 is
connected to the electric vehicle 102, the association unit 116 can
determine that the charging station 106 should associate with the
electric vehicle 102. If the association unit 116 determines that
the charging station 106 is not connected to the electric vehicle
102, the association unit 116 can determine that the charging
station 106 should not associate with the electric vehicle 102. If
it is determined that the service provider should associate with
the client network device, the flow continues at block 422.
Otherwise, if it is determined that the service provider should not
associate with the client network device, the flow continues at
block 424.
[0053] At block 422, the service provider transmits its network
connection parameters to the client network device, associates with
the client network device, and provides service to the client
network device. After determining to associate with the electric
vehicle 102 at block 420, the association unit 116 of the charging
station 106 can transmit a match confirmation message (e.g., a
CM_SLAC_MATCH.CNF message) to the electric vehicle 102. The match
confirmation message can comprise an identifier (e.g., VIN) of the
electric vehicle 102, a MAC address of the electric vehicle 102, an
identifier of the matched charging station 106, a MAC address of
the matched charging station 106, and one or more network
connection parameters associated with a network of the matched
charging station 106. For example, if the charging station 106 is
configured in accordance with the HomePlug Green PHY specification,
the association unit 116 can transmit a network identifier (NID)
and a network membership key (NMK) associated with a network of the
matched charging station 106 in the match confirmation message. If
the charging station 106 and the electric vehicle 102 are
configured to execute the secure association procedure, the network
connection parameters (e.g., the NID and the NMK) and the match
confirmation message can be signed using the charging station's
public key certificate and can be encrypted using the electric
vehicle's public encryption key. Sequence numbers or nonces
associated with the session can be used to prevent replay attacks.
The association unit 116 can transmit the match confirmation
message using multi-network broadcast communication. It is noted
that in some embodiments, prior to transmitting the match
confirmation message, the association unit 116 may also validate
that the electric vehicle 102 is connected to the charging station
106 via a charging cordset using a validation process that will be
further described below.
[0054] In addition to transmitting the network connection
parameters to the electric vehicle 102, the charging station 106
can also configure itself (e.g., the HLE of the charging station
106 can configure the Green PHY module of the charging station 106)
with the same network connection parameters (e.g., the NID and
NMK). This can cause the charging station 106 to become an
unassociated station waiting for another station that has the same
network connection parameters. Once the charging station 106 and
the electric vehicle 102 are configured using the same network
connection parameters (e.g., NID and NMK), the charging station 106
and the electric vehicle 102 can form an AV logical network (AVLN).
It is noted that the charging station 106 may ignore/discard any
communication parameter request messages received from other
electric vehicles as long as the electric vehicle 102 is associated
with the charging station (e.g., as long as the charging station
106 and the electric vehicle 102 are part of the same AVLN). After
the electric vehicle 102 joins the network of the matched charging
station 106, the matched charging station 106 (e.g., an
authentication unit of the matched charging station 106) can
execute appropriate application layer authentication and
authorization procedures with the electric vehicle 102. After the
electric vehicle 102 has been successfully
authenticated/authorized, the matched charging station 106 (e.g., a
charging unit of the matched charging station 106) can close its
power relays and supply electric power to the electric vehicle 102.
From block 422, the flow ends.
[0055] At block 424, another service provider with which the client
network device should associate is identified and the client
network device is notified of the network connection parameters
associated with the other service provider. As discussed above in
block 420, the association unit 116 may determine that the charging
station 106 is not the expected matched charging station and that
the electric vehicle 102 should associate with another charging
station (e.g., the charging station 110). Accordingly, the
association unit 116 can determine network connection parameters
(e.g., NID, NMK, MAC address, etc.) associated with the expected
matched charging station 110. The association unit 116 can override
the electric vehicle's association decision, provide the network
connection parameters associated with the expected matched charging
station 110 to the electric vehicle 102, and prompt the electric
vehicle 102 to associate with the expected matched charging station
110. From block 424, the flow ends.
[0056] It should be noted that although FIG. 5 describes the
association unit 116 transmitting the network connection parameters
associated with the charging station 106 to enable the electric
vehicle 102 to associate with the charging station 106 (at block
422 of FIG. 5), embodiments are not so limited. In other
embodiments, the association unit 112 of the electric vehicle 102
can transmit network connection parameters associated with the
electric vehicle 102, to enable the charging station 106 to
associate with the electric vehicle 102. In other embodiments,
other suitable techniques can be employed to enable the electric
vehicle 102 to associate with the matched charging station 106.
Also, although FIG. 5 describes the association unit 116 (of the
charging station 106) receiving a match notification message from
the electric vehicle 102, determining that the electric vehicle 102
should associate with another charging station 110, and providing
the network connection parameters associated with the other
charging station 110, embodiments are not so limited. In other
embodiments, if the association unit 116 that receives the match
notification message determines that the electric vehicle 102
should associate with another charging station (or that the
charging station 106 is not connected to the electric vehicle 102),
the association unit 116 can simply notify the electric vehicle 102
to re-execute the association procedure (e.g., to re-broadcast the
communication parameters request message of block 202 in FIG.
2).
[0057] It should be understood that FIGS. 1-5 are examples meant to
aid in understanding embodiments and should not be used to limit
embodiments or limit scope of the claims. Embodiments may comprise
additional circuit components, different circuit components, and/or
may perform additional operations, fewer operations, operations in
a different order, operations in parallel, and some operations
differently. In some embodiments, the electric vehicle 102 may
employ a reduced transmit power level during the association
procedure to minimize the number of charging stations that receive
transmissions from the electric vehicle 102. In one implementation,
the association unit 112 of the electric vehicle 102 can initiate
the association procedure (e.g., by transmitting the communication
parameters request message at block 204 of FIG. 2) at a lowest
transmit power level to reduce the number of charging stations that
respond to the communication parameters request message and to
minimize the possibility of receiving communications from charging
stations to which the electric vehicle 102 is not connected. For
example, the association unit 112 may start transmitting the
communication parameters request message at a transmit power level
that is 25 dB below the maximum transmit power level of the
electric vehicle 102. If the association unit 112 does not receive
a communication parameters response message from any of the
charging stations, the association unit 112 can increase the
transmit power level by, for example, 2 dB. If the association unit
112 still does not receive the communication parameters response
message from any of the charging stations, the association unit 112
can increase the transmit power level again (e.g., by 2 dB or
another transmit power increment). This process of incrementally
and iteratively increasing the transmit power level can continue
until the association unit 112 receives a communication parameters
response message including the communication parameters from at
least one charging station 106. The association unit 112 may
continue to communicate with the charging station 106 using the
lowest transmit power level at which the communication parameters
response message was successfully received. In another
implementation, the association unit 112 of the electric vehicle
102 can transmit the communication parameters request message (at
block 204 of FIG. 2) at a normal (or maximum) transmit power level
and can receive communication parameters from some/all of the
charging stations. The association unit 112 can then transmit a set
of service matching messages at a lowest transmit power level to
reduce the number of charging stations that respond to the service
matching messages. If the association unit 112 does not receive a
response (e.g., attenuation information) to the first set of
service matching messages from any of the charging stations, the
association unit 112 can increase the transmit power level and
transmit a second set of service matching messages at a higher
transmit power level. The association unit 112 can incrementally
and iteratively increase the transmit power level until the
association unit 112 receives a response from at least one charging
station.
[0058] It should be noted that in some embodiments, the length of
the service matching message can be larger than a maximum packet
length permitted for transmission ("permissible maximum packet
length") in the communication network. For example, the permissible
maximum packet length may be 502 octets. In some embodiments, the
length of the service matching message may be greater than 502
octets. In this embodiment, the association unit 112 of the
electric vehicle 102 can fragment the service matching message so
that the length of each fragment is less than or equal to the
permissible maximum packet length. The association unit 112 can
transmit the fragments of the service matching message to the
charging stations 106, 108, and 110.
[0059] Although the Figures depict the charging stations 106, 108,
and 110 transmitting their respective attenuation information to
the electric vehicle 102 and the electric vehicle 102 selecting the
matched charging station 106, embodiments are not so limited. In
some embodiments, the charging stations can coordinate to determine
the matched charging station 106 for the electric vehicle 102. For
example, the charging stations 106, 108, and 110 can exchange their
respective attenuation information and can determine the matched
charging station 106 for the electric vehicle 102. In other
embodiments, one of the charging stations 106, 108, and 110 may be
designated as a "master charging station" (e.g., the charging
station 110). The master charging station 110 may receive the
attenuation information from the other charging stations 106 and
108, may select the matched charging station 106, and may notify
the electric vehicle 102 and the matched charging station 106 to
associate with each other and establish a communication link. In
these embodiments, the charging stations 106, 108, and 110 may not
provide their respective attenuation information to the electric
vehicle 102. Instead, one of the charging stations (e.g., the
matched charging station 106 or another "master" charging station
110) may simply notify the electric vehicle 102 of the association
decision (i.e., the matched charging station). In other
embodiments, the charging stations 108, and 110 can transmit their
respective attenuation information to another network device (e.g.,
a central coordinator device). The network device (e.g., the
central coordinator device) that receives the attenuation
information associated with all the charging stations 106, 108, and
110 can analyze the attenuation information, select a matched
charging station 106 for the electric vehicle 102, and notify the
electric vehicle 102 and the matched charging station 106
accordingly.
[0060] Furthermore, in some embodiments, the association unit 112
of the electric vehicle 102 may select the matched charging station
106 from a subset of the charging stations that provide their
attenuation information to the electric vehicle 102. The
association unit 112 can identify a subset of charging stations
that are associated with an attenuation level that is less than a
threshold attenuation level (or a signal level that is greater than
a threshold signal level). For example, the association unit 112
may receive attenuation information from the charging stations 106,
108, and 110. The association unit 112 may determine that the
charging stations 106 and 108 are associated with an attenuation
level that is less than the threshold attenuation level (for
example, a 25 dB threshold attenuation level). The association unit
112 can then select either the charging station 106 or the charging
station 108 as the matched charging station. It is noted that if
none of the charging stations meet the threshold attenuation level,
the association unit 112 can restart the association procedure by
rebroadcasting the communication parameters request message (as
described above in block 202 of FIG. 2) or can indicate failure of
the association procedure (e.g., an inability to receive power from
any of the charging stations).
[0061] In some embodiments, each charging station 106, 108, and 110
that receives the service matching messages from the electric
vehicle 102 can determine whether to transmit their respective
attenuation information to the electric vehicle 102. For example,
the association unit 116 of the charging station 106 can determine
the attenuation level associated with the charging station 106
(e.g., based on the received service matching messages). The
association unit 116 can determine whether the attenuation level
associated with the charging station 106 lies below a threshold
attenuation level. The threshold attenuation level may be
predetermined and may be calculated based on the expected
attenuation of a signal received from the electric vehicle to which
the charging station is directly connected. If the attenuation
level associated with the charging station 106 is below the
threshold attenuation level, the association unit 116 may
automatically determine that the charging station 106 it is not
directly connected to the electric vehicle 102. Accordingly, the
association unit 116 may not transmit the attenuation information
associated with the charging station 106 to the electric vehicle
102.
[0062] In some embodiments, the matched charging station 106 (e.g.,
the association unit 116) may also transmit an amplitude map
associated with the matched charging station 106 to the electric
vehicle 102 (e.g., in a CM_AMP_MAP.REQ message). The electric
vehicle 102 (e.g., the association unit 112) may also optionally
provide the amplitude map associated with the electric vehicle 102
to the matched charging station 106 (e.g., in a CM_AMP_MAP.CNF
message). The electric vehicle 102 and the matched charging station
106 can use the amplitude maps (of the electric vehicle 102 and the
matched charging station 106) to determine the transmit power level
that should be used for communication. The electric vehicle 102 and
the matched charging station 106 can use the amplitude maps to
adjust the amplitude of each unmasked carrier of the communication
band (e.g., a powerline communication band) for all subsequent
communications between the electric vehicle 102 and the matched
charging station 106. The amplitude maps can enable the electric
vehicle 102 and the matched charging station 106 to determine a
transmit amplitude reduction for each unmasked carrier (beginning
at the lowest frequency carrier). For example, the transmit power
level that is used (e.g., by the electric vehicle 102 and the
matched charging station 106) on various carrier frequencies may be
based on the minimum of the charging station's amplitude map and
the electric vehicle's amplitude map. This can take into
consideration any uncertainty/sensitivity to specific PLC carrier
frequencies (at the electric vehicle and/or the matched charging
station).
[0063] It is noted that the charging stations and the electric
vehicle can form a network using various suitable techniques. In
some embodiments, the electric vehicle 102 may not join a network
associated with any of the charging stations 106, 108, and 110
until the association procedure is completed and the matched
charging station is identified. In this embodiment, the electric
vehicle 102 and the charging stations 106, 108, and 110 can use
multi-network broadcast communications to reliably communicate with
each other even though the electric vehicle 102 and the charging
stations 106, 108, and 110 are not part of the same communication
network. The operations of FIG. 1-5 using multi-network broadcast
communications can be employed in environments where all the
charging stations 106, 108, and 110 cannot form a single
communication network (e.g., because of attenuation characteristics
between the charging stations, because charging stations that
belong to different owners (e.g., different manufacturers) may not
be configured to communicate with each other, etc.). For example in
a large parking lot, charging stations that are far away from each
other may not be able to communicate with or "hear" each other. In
this example, charging stations may form multiple networks and the
electric vehicle 102 may communicate with charging stations from
different communication networks. In some implementations, each
charging station can be configured to form a communication network
with those charging stations that are within a predetermined
proximity. In other implementations, each charging station can be
configured never to form a communication network with other
charging stations.
[0064] In another embodiment, the electric vehicle 102 may join the
network associated with one of the charging stations prior to
initiating the association procedure. For example, the electric
vehicle 102 and one of the charging stations 106 may use a suitable
authentication mechanism (e.g., a unicast key exchange (UKE) based
authentication mechanism) to form the network. In this example, a
button associated with the electric vehicle 102 and the charging
station 106 can be activated and, in response, the electric vehicle
102 and the charging station 106 can determine that they are
connected via a charging cordset using, for example, a proximity
detect feature. Proximity detect is a safety feature that enables
the electric vehicle 102 and the charging station 106 to determine
that they are physically connected so that the electric vehicle 102
is prevented from moving when the electric vehicle 102 is plugged
into the charging station 106. In another embodiment, all the
charging stations 106, 108, and 110 may be part of a common network
and the electric vehicle 102 can join the common network prior to
initiating (or as part of) the association procedure.
[0065] In some embodiments, each charging station 106, 108, and 110
may comprise one or more filter units to prevent signals received
from the electric vehicle 102 from leaking to other charging
stations. For example, if the charging station 106 receives a
communication parameters request message from the electric vehicle
102, the filter unit associated with the charging station 106 can
minimize/block appropriate frequencies so that the other charging
stations 108 and 110 do not receive the communication parameters
request message via the charging station 106 (or so that the
charging stations 108 and 110 receive the communication parameters
request message via the charging station 106 with a very high
attenuation, or with very high attenuation on particular frequency
bands). In some embodiments, the charging stations 106, 108, and
110 may also employ shielded cables to connect to an electric
vehicle 102. This can enable isolation of signals transmitted by
the electric vehicle 102, thus minimizing the possibility that
charging stations that are not directly connected to the electric
vehicle 102 detect signals from the electric vehicle 102 with a
high signal level.
[0066] In some embodiments, after a charging station 106 receives a
match notification message from the electric vehicle 102 indicating
that the charging station 106 was selected as the matched charging
station, the charging station (e.g., the association unit 116 or
another suitable validation unit) can use suitable validation
techniques to validate that the electric vehicle 102 is connected
to the matched charging station 106. In some embodiments, the
matched charging station 106 can use suitable out-of-band
validation techniques that use a more secure communication medium
to validate the electric vehicle 102 compared to the communication
medium used for the association procedure. The communication medium
used for validation may be a low bandwidth communication medium,
but that is less susceptible to interception, modification, or
spoofing than the communication medium that was used for executing
the association procedure. In one example, the charging station 106
can modify the duty cycle of the Pulse Width Modulated (PWM)
Control Pilot signal. The charging station (e.g., the HLE of the
charging station 106) can transmit a validation request message
(e.g., a CM_VALD_PWM.REQ message) to the electric vehicle 102
(e.g., to the HLE of the electric vehicle 102). The validation
request message can serve as a request to the electric vehicle 102
to read the pilot line pulse width modulation value and transmit
the value to the charging station 106. In some embodiments, the
charging station 106 can transmit the validation request message
using multi-network broadcast communication. In some embodiments,
the charging station 106 can retransmit the validation request
message until a validation confirmation message (e.g., a
CM_VALD_PWM.CNF message) is received from the electric vehicle 102.
After the electric vehicle 102 receives the validation request
message, the electric vehicle 102 can determine the pilot line
pulse width modulation value (e.g., a measured duty cycle value)
and transmit this value to the charging station 106 in the
validation confirmation message. In some embodiments, the electric
vehicle 102 can transmit the validation confirmation message using
multi-network broadcast communication. In response to receiving the
validation confirmation message, the charging station 106 can
compare the measured duty cycle value with the duty cycle value
reported by the electric vehicle 102. If there is a match, the
charging station 106 can transmit the match confirmation message
(e.g., a CM_SLAC_MATCH.CNF message) discussed above at block 422 of
FIG. 5, indicating that the validation process was successful.
[0067] It is noted that in some embodiments, the public key
certificate (e.g., the X.509v3 certificate) may be too large for
multi-network broadcast transmission. In this embodiment, various
techniques can be employed for transmitting the public key
certificate (e.g., from the electric vehicle 102 to the charging
station 106). In some implementations, the charging station 106 can
first obtain the electric vehicle's identity from the electric
vehicle 102 and can then obtain the certificate associated with the
electric vehicle 102 from an authorization server or a cache. In
another implementation, the electric vehicle 102 can fragment its
public key certificate and transmit fragments of the public key
certificate to the charging station 106 across multiple MNBC
transmissions. Likewise, similar operations can be executed to
provide the public key certificates associated with the charging
stations to the electric vehicle 102.
[0068] Finally, in some embodiments, the electric vehicle 102 and
the charging station (e.g., the charging station 106) may also
exchange user data as part of the association procedure. The user
data can be exchanged to indicate, for example, that the electric
vehicle 102 has disconnected from the charging station 106 (e.g.,
immediate disassociate), that the charging process should be
terminated, etc.
[0069] As will be appreciated by one skilled in the art, aspects of
the present inventive subject matter may be embodied as a system,
method, or computer program product. Accordingly, aspects of the
present inventive subject matter may take the form of an entirely
hardware embodiment, a software embodiment (including firmware,
resident software, micro-code, etc.) or an embodiment combining
software and hardware aspects that may all generally be referred to
herein as a "circuit," "module" or "system." Furthermore, aspects
of the present inventive subject matter may take the form of a
computer program product embodied in one or more computer readable
medium(s) having computer readable program code embodied
thereon.
[0070] Any combination of one or more computer readable medium(s)
may be utilized. The computer readable medium may be a computer
readable signal medium or a computer readable storage medium. A
computer readable storage medium may be, for example, but not
limited to, an electronic, magnetic, optical, electromagnetic,
infrared, or semiconductor system, apparatus, or device, or any
suitable combination of the foregoing. More specific examples (a
non-exhaustive list) of the computer readable storage medium would
include the following: an electrical connection having one or more
wires, a portable computer diskette, a hard disk, a random access
memory (RAM), a read-only memory (ROM), an erasable programmable
read-only memory (EPROM or Flash memory), an optical fiber, a
portable compact disc read-only memory (CD-ROM), an optical storage
device, a magnetic storage device, or any suitable combination of
the foregoing. In the context of this document, a computer readable
storage medium may be any tangible medium that can contain, or
store a program for use by or in connection with an instruction
execution system, apparatus, or device.
[0071] A computer readable signal medium may include a propagated
data signal with computer readable program code embodied therein,
for example, in baseband or as part of a carrier wave. Such a
propagated signal may take any of a variety of forms, including,
but not limited to, electro-magnetic, optical, or any suitable
combination thereof. A computer readable signal medium may be any
computer readable medium that is not a computer readable storage
medium and that can communicate, propagate, or transport a program
for use by or in connection with an instruction execution system,
apparatus, or device.
[0072] Program code embodied on a computer readable medium may be
transmitted using any appropriate medium, including but not limited
to wireless, wireline, optical fiber cable, RF, etc., or any
suitable combination of the foregoing.
[0073] Computer program code for carrying out operations for
aspects of the present inventive subject matter may be written in
any combination of one or more programming languages, including an
object oriented programming language such as Java, Smalltalk, C++
or the like, conventional procedural programming languages, such as
the "C" programming language or similar programming languages, and
assembler or machine programming languages. The program code may
execute entirely on the user's computer, partly on the user's
computer, as a stand-alone software package, partly on the user's
computer and partly on a remote computer or entirely on the remote
computer or server. In the latter scenario, the remote computer may
be connected to the user's computer through any type of network,
including a local area network (LAN) or a wide area network (WAN),
or the connection may be made to an external computer (for example,
through the Internet using an Internet Service Provider).
[0074] Aspects of the present inventive subject matter are
described with reference to flowchart illustrations and/or block
diagrams of methods, apparatus (systems) and computer program
products according to embodiments of the inventive subject matter.
It will be understood that each block of the flowchart
illustrations and/or block diagrams, and combinations of blocks in
the flowchart illustrations and/or block diagrams, can be
implemented by computer program instructions. These computer
program instructions may be provided to a processor of a general
purpose computer, special purpose computer, or other programmable
data processing apparatus to produce a machine, such that the
instructions, which execute via the processor of the computer or
other programmable data processing apparatus, create means for
implementing the functions/acts specified in the flowchart and/or
block diagram block or blocks.
[0075] These computer program instructions may also be stored in a
computer readable medium that can direct a computer, other
programmable data processing apparatus, or other devices to
function in a particular manner, such that the instructions stored
in the computer readable medium produce an article of manufacture
including instructions which implement the function/act specified
in the flowchart and/or block diagram block or blocks.
[0076] The computer program instructions may also be loaded onto a
computer, other programmable data processing apparatus, or other
devices to cause a series of operational steps to be performed on
the computer, other programmable apparatus or other devices to
produce a computer implemented process such that the instructions
which execute on the computer or other programmable apparatus
provide processes for implementing the functions/acts specified in
the flowchart and/or block diagram block or blocks.
[0077] FIG. 6 is a block diagram of one embodiment of an electronic
device 600 including an attenuation level based association
mechanism in a communication network. In some implementations, the
communication network may be a public charging facility and the
electronic device 600 may be a charging station (e.g., an electric
vehicle supply equipment (EVSE) device). In other implementations,
the electronic device 600 may be an electric vehicle (e.g., a
plug-in electric vehicle or PEV) configured to receive electric
power from one of the charging stations in the charging facility.
The electronic device 600 (whether a charging station or an
electric vehicle) may comprise wired communication capabilities
(e.g., powerline communication capabilities) and/or wireless
communication capabilities (e.g., WLAN communication capabilities).
The electronic device 600 includes a processor unit 602 (possibly
including multiple processors, multiple cores, multiple nodes,
and/or implementing multi-threading, etc.). The electronic device
600 includes a memory unit 606. The memory unit 606 may be system
memory (e.g., one or more of cache, SRAM, DRAM, zero capacitor RAM,
Twin Transistor RAM, eDRAM, EDO RAM, DDR RAM, EEPROM, NRAM, RRAM,
SONOS, PRAM, etc.) or any one or more of the above already
described possible realizations of machine-readable media. The
electronic device 600 also includes a bus 610 (e.g., PCI, ISA,
PCI-Express, HyperTransport.RTM. , InfiniBand.RTM. , NuBus, AHB,
AXI, etc.), and network interfaces 604 that include at least one of
a wireless network interface (e.g., a Bluetooth interface, a WLAN
802.11 interface, a WiMAX interface, a ZigBee.RTM. interface, a
Wireless USB interface, etc.) and a wired network interface (e.g.,
an Ethernet interface, a powerline communication interface,
etc.).
[0078] The electronic device 600 also includes a communication unit
608. The communication unit 608 comprises an association unit 612
and a processor unit 614. When the electronic device 600 is an
electric vehicle, the communication unit 608 can execute operations
described above with reference to FIGS. 1-3 to exchange
communications with one or more charging stations of a charging
facility and identify a charging station with which to associate
and from which to receive electric power. When the electronic
device 600 is a charging station, the communication unit 608 can
execute operations described above in FIGS. 1 and 4-5 to provide
attenuation information associated with the charging station to the
electric vehicle and (if selected as the matched charging station)
associate with and provide power to the electric vehicle. In some
embodiments, the processor unit 614 may execute the functionality
of the association unit 612. In other embodiments, the processor
unit 602 may execute the functionality of the association unit 612.
In other embodiments, the processor units 602 and 614 may execute
the functionality of the association unit 612 in conjunction.
[0079] Any one of these functionalities may be partially (or
entirely) implemented in hardware and/or on the processor unit 602.
For example, the functionality may be implemented with an
application specific integrated circuit, in logic implemented in
the processor unit 602, in a co-processor on a peripheral device or
card, etc. Further, realizations may include fewer or additional
components not illustrated in FIG. 6 (e.g., video cards, audio
cards, additional network interfaces, peripheral devices, etc.).
The processor unit 602, the memory unit 606, and the network
interfaces 604 are coupled to the bus 610. Although illustrated as
being coupled to the bus 610, the memory unit 606 may be coupled to
the processor unit 602.
[0080] While the embodiments are described with reference to
various implementations and exploitations, it will be understood
that these embodiments are illustrative and that the scope of the
inventive subject matter is not limited to them. In general, an
attenuation level based association mechanism as described herein
may be implemented with facilities consistent with any hardware
system or hardware systems. Many variations, modifications,
additions, and improvements are possible.
[0081] Plural instances may be provided for components, operations,
or structures described herein as a single instance. Finally,
boundaries between various components, operations, and data stores
are somewhat arbitrary, and particular operations are illustrated
in the context of specific illustrative configurations. Other
allocations of functionality are envisioned and may fall within the
scope of the inventive subject matter. In general, structures and
functionality presented as separate components in the exemplary
configurations may be implemented as a combined structure or
component. Similarly, structures and functionality presented as a
single component may be implemented as separate components. These
and other variations, modifications, additions, and improvements
may fall within the scope of the inventive subject matter.
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