U.S. patent application number 15/475338 was filed with the patent office on 2018-10-04 for dual mode communication over automotive power lines.
The applicant listed for this patent is GM GLOBAL TECHNOLOGY OPERATIONS LLC. Invention is credited to Yohay Buchbut, Moshe Laifenfeld, Tal Philosof.
Application Number | 20180287664 15/475338 |
Document ID | / |
Family ID | 63671095 |
Filed Date | 2018-10-04 |
United States Patent
Application |
20180287664 |
Kind Code |
A1 |
Laifenfeld; Moshe ; et
al. |
October 4, 2018 |
DUAL MODE COMMUNICATION OVER AUTOMOTIVE POWER LINES
Abstract
A system for communication over automotive power lines is
described. The system includes a plurality of vehicle modules. Each
of the vehicle modules includes a power line communication (PLC)
module. A PLC network connects the power lines configured to carry
electric power to the vehicle modules. The PLC processors enable
the power lines to transmit data between the plurality of vehicle
modules. The system also includes a master PLC processor configured
to transmit data to one or more of the plurality of vehicle modules
via one of two selectable protocols that include a multiple
frequency channel communication protocol and a multiple input
multiple output (MIMO) communication protocol.
Inventors: |
Laifenfeld; Moshe; (Haifa,
IL) ; Buchbut; Yohay; (Pardes Hanna, IL) ;
Philosof; Tal; (Givatayim, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GM GLOBAL TECHNOLOGY OPERATIONS LLC |
Detroit |
MI |
US |
|
|
Family ID: |
63671095 |
Appl. No.: |
15/475338 |
Filed: |
March 31, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 69/18 20130101;
H04B 3/542 20130101; H04L 67/12 20130101; H04L 5/0012 20130101 |
International
Class: |
H04B 3/54 20060101
H04B003/54; H04L 29/08 20060101 H04L029/08; H04L 5/00 20060101
H04L005/00 |
Claims
1. A system, comprising: a plurality of vehicle modules each
comprising a power line communication (PLC) module; a PLC network
comprising power lines configured to carry electric power to the
vehicle modules, wherein the PLC processors enable the power lines
to transmit data between the plurality of vehicle modules; and a
master PLC processor of the plurality of PLC processors configured
to transmit data to one or more of the plurality of vehicle modules
via one of two selectable protocols comprising a multiple frequency
channel communication protocol and a multiple input multiple output
(MIMO) communication protocol; wherein the master PLC processor
transmits a test signal on two or more power lines connected to the
master PLC processor; selects at least one power line channel of
the two or more power lines based on the test signal attenuation;
and transmits the data to one or more of the plurality of vehicle
modules via the at least one selected power line channel.
2. The system of claim 1, wherein the master PLC processor is
configured to transmit the data using both of the multiple
frequency channel communication protocol and the MIMO communication
protocol, wherein the two protocols are user-selectable.
3. The system of claim 1, wherein the master PLC processor is
configured to transmit the data using the multiple frequency
channel communication protocol by frequency hopping on two or more
frequency channels operating on the same power line.
4. The system of claim 3, wherein the master PLC processor is
configured to: select a pseudo-orthogonal frequency sequence of the
two or more frequency channels, wherein the frequency sequence
comprises a main transmission frequency and one or more frequencies
that are not harmonics of the main transmission frequency; and
transmit the data by frequency hopping on the two or more frequency
channels based on the selected pseudo-orthogonal frequency
sequence.
5. The system of claim 4, wherein the master PLC processor is
configured to transmit the data on a different frequency of the two
or more frequency channels at a predetermined time interval between
each of the frequency channels.
6. The system of claim 1, wherein the master PLC processor is
configured to transmit the data using the MIMO communication
protocol, wherein the processor is configured to select at least
one power line channel based on a system response to a test signal
transmitted on the power line channel.
7. The system of claim 6, wherein master PLC processor is
configured to: transmit the test signal on the two or more power
lines connected to the master PLC processor; select, based on the
system response of the test signal, the at least one power line
channel of the one or more power lines connected to the master PLC
processor; and transmit the data to one or more of the plurality of
vehicle modules via the at least one selected power line
channel.
8. The system of claim 7, wherein the system response comprises a
signal attenuation of the test signal, and the master PLC processor
selects the at least one power line based on a predetermined range
of signal attenuations.
9. The system of claim 7, wherein the system response comprises a
signal amplitude of the test signal, and the master PLC processor
selects the at least one power line based on a predetermined range
of signal amplitudes.
10. The system of claim 7, wherein the system response tested is
changeable by a user to select the at least one power line based on
a user-determined criterion.
11. A method for PLC in a vehicle comprising: transmitting data,
via a master PLC processor, to one or more of a plurality of
vehicle modules in the vehicle via one of two selectable protocols
comprising a multiple frequency channel communication protocol and
a multiple input multiple output (MIMO) communication protocol;
wherein the master PLC processor transmits a test signal on two or
more power lines connected to the master PLC processor; selects at
least one power line channel of the two or more power lines based
on the test signal attenuation; and transmits the data to one or
more of the plurality of vehicle modules via the at least one
selected power line channel.
12. The method of claim 11, comprising: transmitting the data using
both of the multiple frequency channel communication protocol and
the MIMO communication protocol, wherein the two protocols are
user-selectable.
13. The method of claim 11, comprising: transmitting the data
selective to the multiple frequency channel communication protocol
with frequency hopping on two or more frequency channels operating
on the same power line.
14. The method of claim 13, comprising: selecting, via the
processor, a pseudo-orthogonal frequency sequence comprising the
two or more frequency channels, wherein the frequency sequence
comprises a main transmission frequency and one or more frequencies
that are not harmonics of the main transmission frequency; and
transmitting the data by frequency hopping on the two or more
frequency channels based on the selected pseudo-orthogonal
frequency sequence.
15. The method of claim 14, comprising: transmitting the data on a
different frequency of the two or more frequency channels at a
predetermined time interval between each of the frequency
channels.
16. The method of claim 11, wherein transmitting the data
comprises: transmitting the data using the MIMO communication
protocol by selecting at least one power line channel based on a
system response to a test signal transmitted on the power line
channel.
17. The method of claim 16, comprising: transmitting, via the
processor, the test signal on the two or more power lines connected
to the master PLC processor; selecting, via the processor, based on
the system response of the test signal, the at least one power line
channel of the one or more power lines connected to the master PLC
processor; and transmitting the data to one or more of the
plurality of vehicle modules via the at least one selected power
line channel.
18. The method of claim 17, wherein the system response comprises a
signal attenuation of the test signal, and the selecting comprises
selecting the at least one power line based on a predetermined
range of signal attenuations.
19. The method of claim 17, wherein the system response comprises a
signal amplitude of the test signal, and the master PLC processor
selects the at least one power line based on a predetermined range
of signal amplitudes.
20. A vehicle comprising a power line communication system
comprising: a plurality of vehicle modules each comprising a power
line communication (PLC) module; a PLC network comprising power
lines configured to carry electric power to the vehicle modules,
wherein the PLC processors enable the power lines to transmit data
between the plurality of vehicle modules; and a master PLC
processor of the plurality of PLC processors configured to:
transmit data to one or more of the plurality of vehicle modules
via one of two selectable protocols comprising a multiple frequency
channel communication protocol and a multiple input multiple output
(MIMO) communication protocol; wherein the master PLC processor
transmits a test signal on two or more power lines connected to the
master PLC processor; selects at least one power line channel of
the two or more power lines based on the test signal attenuation;
and transmits the data to one or more of the plurality of vehicle
modules via the at least one selected power line channel.
Description
INTRODUCTION
[0001] The subject disclosure relates to vehicles, and more
particularly to dual mode local interconnect network
(LIN)/controller area network (CAN) communication over automotive
power lines.
[0002] Power-line communication (PLC) generally refers to
technologies in which a power line that is designed to carry
electric power also carries data between two nodes in a network.
Power-line communications systems operate by adding a modulated
carrier signal to the wiring system. PLC can eliminate the need for
installation of dedicated communication lines when power lines
connect the control modules.
[0003] Recently, power-line communication has been proposed for use
in vehicles to reduce the number of wires needed in a vehicle by
sending communication signals over the vehicle's existing
power-lines. PLC technology enables communication data and control
information over existing direct current (DC) battery power-lines.
PLC in vehicles can reduce and/or eliminate the need for wiring
that would normally be included in the vehicle to carry
communication information. Vehicle cost and weight can therefore be
reduced.
[0004] Current DC power line communication concepts transmit data
on a single fixed frequency. However, data error rates outside of a
permissible range can result due to interference and channel
conditions caused by operation of one or more vehicle systems at
the same time. Current low cost DC power line communication systems
in automobiles are symmetric in nature (i.e., master and node have
identical capabilities) and are narrowband in nature; where every
LIN bus being replaced occupies a fixed frequency band. Experiments
show, however, that not all frequency bands are supported by the
vehicle distribution network, and predicting which bands are
suitable for static frequency transmission (and which bands are
not) is technically challenging, if not impractical.
[0005] Most LIN buses in an automobile's electrical architecture
are driven by a small subset of ECUs operating as LIN masters that
respectively drive multiple LIN buses. A body control module (BCM)
is an example of a LIN master that drives multiple LIN buses. Such
scenarios call for asymmetric design where the LIN master has
significantly more computational capability than the end nodes. But
the narrowband communications on LIN buses may experience
interference and channel conditions when used for data transmission
when other vehicle functions are performed on one or more of the
LIN buses. Wideband technologies like orthogonal frequency-division
multiplexing (OFDM) methods are resilient to channel conditions,
however hardware and field implementation for OFDM can be cost
prohibitive in vehicle PLC networks.
[0006] Accordingly, it is desirable to provide cost-effective
systems for reliable and robust communication of multiple LIN /CAN
buses over multiple power line paths, and further, over multiple
frequency bands, that can be driven by a single master power line
communication processor.
SUMMARY
[0007] In one exemplary embodiment, a system for communication over
automotive power lines is described. The power line communication
(PLC) system includes a plurality of vehicle modules each with a
PLC processor, which are connected via power lines in a PLC
network. The power lines are configured to carry electric power to
the vehicle modules. The PLC processors enable the power lines to
also transmit data between the plurality of vehicle modules. The
system includes a master PLC processor configured to transmit data
to one or more of the plurality of vehicle modules via one of two
selectable protocols that include a multiple frequency channel
communication protocol, and a multiple input multiple output (MIMO)
communication protocol.
[0008] In another exemplary embodiment, a method for power line
communication (PLC) in a vehicle includes transmitting data via a
master PLC processor to one or more of a plurality of vehicle
modules in the vehicle. The master PLC processor is configured to
transmit the data via one of two selectable protocols that include
a multiple frequency channel communication protocol, and a multiple
input multiple output (MIMO) communication protocol.
[0009] In another exemplary embodiment, a vehicle includes a power
line communication (PLC) system. The PLC system includes a
plurality of vehicle modules each with a PLC module, which are
connected via power lines in a PLC network. The power lines are
configured to carry electric power to the vehicle modules. The PLC
processors also enable the power lines to also transmit data
between the plurality of vehicle modules. The vehicle includes a
master PLC processor configured to transmit data to one or more of
the plurality of vehicle modules via one of two selectable
protocols that include a multiple frequency channel communication
protocol, and a multiple input multiple output (MIMO) communication
protocol.
[0010] In addition to one or more of the features described herein,
in one embodiment the master PLC processor is configured to
transmit the data using both of the multiple frequency channel
communication protocol and the MIMO communication protocol, where
the two protocols are user-selectable.
[0011] In another embodiment, the master PLC processor is
configured to transmit the data using the multiple frequency
channel communication protocol with frequency hopping on two or
more frequency channels operating on the same power line.
[0012] In another embodiment, where the master PLC processor is
configured to transmit the data using the multiple frequency
channel communication protocol, the master PLC processor is
configured to select a pseudo-orthogonal frequency sequence of two
or more frequency channels. The frequency sequence includes a main
transmission frequency and one or more frequencies that are not
harmonics of the main transmission frequency. The master PLC
processor transmits the data by frequency hopping on the two or
more frequency channels based on the selected pseudo-orthogonal
frequency sequence.
[0013] In another embodiment, where the master PLC processor is
configured to transmit the data using the multiple frequency
channel communication protocol, the master PLC processor is
configured to transmit the data on a different frequency of the two
or more frequency channels at a predetermined time interval between
each of the frequency channels.
[0014] In another embodiment, where the master PLC processor is
configured to transmit the data using the MIMO communication
protocol, the master PLC processor is configured to select at least
one power line channel based on a system response to a test signal
transmitted on the power line channel.
[0015] In another embodiment, where the master PLC processor is
configured to transmit the data using the MIMO communication
protocol, the master PLC processor transmits a test signal on two
or more power lines connected to the master PLC processor, and
selects, based on the system response of the test signal, the at
least one power line channel of the one or more power lines
connected to the master PLC processor. The PLC processor transmits
the data to one or more of the plurality of vehicle modules via the
at least one selected power line channel.
[0016] In another embodiment, where the master PLC processor is
configured to transmit the data using the MIMO communication
protocol, the system response includes a signal attenuation of the
test signal, and the master PLC processor selects the at least one
power line based on a predetermined range of signal
attenuations.
[0017] In another embodiment, where the master PLC processor is
configured to transmit the data using the MIMO communication
protocol, the system response includes a signal amplitude of the
test signal, and the master PLC processor selects the at least one
power line based on a predetermined range of signal amplitudes.
[0018] In another embodiment, where the master PLC processor is
configured to transmit the data using the MIMO communication
protocol, system response tested is changeable by a user to select
the at least one power line based on a user-determined
criterion.
[0019] The above features and advantages, and other features and
advantages of the disclosure, are readily apparent from the
following detailed description when taken in connection with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Other features, advantages and details appear, by way of
example only, in the following detailed description, the detailed
description referring to the drawings in which:
[0021] FIG. 1 illustrates a vehicle in accordance with various
embodiments;
[0022] FIG. 2 is a simplified schematic block diagram of a vehicle
communications network in accordance with various embodiments;
[0023] FIG. 3 is another simplified schematic block diagram of a
power line communication (PLC) network in accordance with various
embodiments; and
[0024] FIG. 4 is a graph illustrating frequency hopping in a
multiple frequency channel communication protocol in accordance
with various embodiments.
DETAILED DESCRIPTION
[0025] The following description is merely exemplary in nature and
is not intended to limit the present disclosure, its application or
uses. It should be understood that throughout the drawings,
corresponding reference numerals indicate like or corresponding
parts and features. As used herein, the term module refers to
processing circuitry that may include an application specific
integrated circuit (ASIC), an electronic circuit, a processor
(shared, dedicated, or group) and memory that executes one or more
software or firmware programs, a combinational logic circuit,
and/or other suitable components that provide the described
functionality.
[0026] More particularly, as used herein, a "vehicle module" refers
to a controller module in a vehicle that controls vehicle systems,
sub-systems, actuators, sensors, switches and the like. Each of the
vehicle modules can perform a certain function or functions for
controlling a certain vehicle system or sub-system, such as a
vehicle body, engine, chassis, etc. Non-limiting examples of
vehicle modules can include, for example, an Engine Control Unit
(ECU) or Engine Control Module (ECM), Powertrain Control Module
(PCM), a Transmission Control Module (TCM), a Body Control Module
(BCM), an Extended Body Control Module (EBCM), a Passive Entry
Passive Start (PEPS) module, a Power Window and Lock Control Module
(PWLCM), an Electrical Parking Brake Control Module (EPBCM), a Door
Switch Panel Module (DSPM), a Vehicle Communication Interface
Module (VCIM), an Electronic Brake Control Module (EBCM), Vehicle
Communication Module (VCM), etc.
[0027] As used herein, a power line (PL) refers to a transmission
line (or a conductor) in a vehicle that carries electric power to
vehicle modules. The power line can be, for example, a direct
current (DC) battery power-line, an alternating current (AC) line
(e.g., in an electric vehicle), or any other conventional
transmission line that is in a vehicle, etc.).
[0028] FIG. 1 illustrates a vehicle 100 that includes a power
source 110 (e.g., a vehicle battery), power lines 120 and a
controller area network (CAN) bus 125 connecting a number of
vehicle modules 130-1 . . . 130-N (collectively "vehicle modules
130"). Power lines 120 are configured in a power line communication
network such that they are a part of CAN bus 125. Although this
drawing illustrates nine vehicle modules 130-1 . . . 130-N, those
skilled in the art will appreciate that this is simply one
non-limiting example and that a vehicle can include any number of
vehicle modules located throughout vehicle 100. Vehicle modules 130
are coupled to the CAN bus 125 via wired or wireless communication
links for communication of information to and from the vehicle
modules 130. Although not illustrated for simplicity, vehicle 100
may also include a number of hard-wired and wireless peripherals,
such as sensors, switches, actuators, etc. Any suitable
configuration of vehicle modules and peripherals can be
employed.
[0029] As shown in FIG. 2, a power line communication network 200
includes a power source (e.g., power source 110 which may be, for
example, a vehicle battery), power lines 120-1 . . . 120-N
(collectively "power lines 120"), an optional Controller Area
Network (CAN) bus line 125 with optional bus lines 125-1 . . .
125-N (collectively "bus lines 125"), and vehicle modules 130-1 . .
. 130-N (collectively "vehicle modules 130"). Power lines 120 are
configured in a power line communication network such that they are
a part of CAN bus 125.
[0030] In one non-limiting embodiment, bus line 125 may be a CAN
bus that is complaint with any known CAN bus standard. As is known
in the art, CAN bus may refer to a message-based protocol designed
for automotive applications that allows microcontrollers, modules,
and devices within a vehicle to communicate with each other without
a host computer. It should be appreciated that a CAN uses
differential signaling mechanisms for electrically transmitting
information using two complementary signals. CANs send the same
electrical signal as a differential pair of signals, each in its
own conductor. The pair of conductors can be wires (typically
twisted together) or traces on a circuit board in single-board CAN
implementations. The receiving circuit responds to the electrical
difference between the two signals rather than the difference
between a single wire and ground. Although the schematics shown in
in FIG. 1 depicts a single wire connection on CAN buses 125, it
should be appreciated that, as depicted in FIG. 2, embodiments
having CANs include multiple wire connections between the vehicle
modules.
[0031] Main power line 120 is electrically coupled to a power
source (e.g., 110 as shown in FIG. 1), such as a vehicle battery.
Main power line 120 is coupled to the vehicle modules 130 via power
lines 120. This way power lines 120 can provide electrical power to
the various vehicle modules 130 of vehicle 100 from power source
110. For example, vehicle module 130-1 couples to main power line
120 via branch power line 120-1. In accordance with the disclosed
embodiments, each of vehicle modules 130 can include a power line
communication module (e.g., PLC processors 240-1 to 240-N) that
allows a power line communication network to be implemented within
the vehicle 100.
[0032] Aspects of the present disclosure involve dual mode
communication over automotive powerlines in a LIN (Local
Interconnect Network) and controller area network (CAN). Before
discussing embodiments in greater detail, brief overviews of both
LIN and CAN technologies are considered in the following
paragraphs.
[0033] As used herein, LIN is a serial network protocol used for
communication between components in vehicles. LIN is a broadcast
serial network usually including up to 16 nodes (one master node
and typically up to 15 slave nodes). All messages are initiated by
the master node with at most one slave node replying to a given
message identifier. The master node can also act as a slave by
replying to its own messages. Because all communications are
initiated by the master it is not necessary to implement a
collision detection. The master and slaves are typically
microcontrollers, but may be implemented in specialized hardware or
ASICs in order to save cost, space, or power. Current automotive
uses combine the low-cost efficiency of LIN and simple sensors to
create small networks. Some embodiments may connect these
sub-systems by a back-bone-network (e.g., CAN bus line 125).
[0034] As used herein, single-carrier frequency division multiple
access (SC-FDMA) is a frequency-division multiple access
communication technology. SC-FDMA deals with the assignment of
multiple users (or in the present case, vehicle modules) to a
shared communication resource. In telecommunications, SC-FDMA has
drawn great attention as an attractive alternative to wideband
technologies like orthogonal frequency-division multiplexing
(OFDM), especially in the uplink communications where lower
peak-to-average power ratio (PAPR) greatly benefits the mobile
terminal in terms of transmit power efficiency and reduced cost of
the power amplifier. For this reason, in the telecommunications
industry, SC-FDMA has been adopted as the uplink multiple access
scheme in non-automotive applications such as 3GPP Long Term
Evolution (LTE), or Evolved UTRA (E-UTRA).
[0035] Although the performance gap of SC-FDMA in relation to OFDMA
is small, SC-FDMA's advantage of low PAPR makes SC-FDMA desirable
when transmitter power efficiency and cost are of paramount
importance. In some exemplary embodiments, SC-FDMA is configured to
use a narrow bandwidth while keeping error rates low in comparison
to current PLC methods. This feature is due, at least in part, to
localized mapping and distributed mapping features of SC-FDMA
technology.
[0036] One distinguishing feature of SC-FDMA is that it leads to a
single-carrier transmit signal, in contrast to OFDMA which is a
multi-carrier transmission scheme that occupies a wide bandwidth.
Subcarrier mapping can be classified into two types: localized
mapping and distributed mapping. In localized mapping, the discrete
Fourier transform (DFT) outputs are mapped to a subset of
consecutive subcarriers, thereby confining them to only a fraction
of the system bandwidth. In distributed mapping, the DFT outputs of
the input data are assigned to subcarriers over the entire
bandwidth, non-continuously, resulting in zero amplitude for the
remaining subcarriers.
[0037] Owing to its inherent single carrier structure, one
prominent advantage of SC-FDMA over OFDM is that the transmit
signal of SC-FDMA has a lower peak-to-average power ratio (PAPR),
resulting in relaxed design parameters in the transmit path of a
subscriber unit (e.g., a receiving vehicle module). According to
embodiments described herein, the relaxed design parameters can
benefit the OEM by reducing design complexity and overall system
cost.
[0038] In SC-FDMA, equalization is achieved on the receiver side,
after the DFT calculation, by multiplying each Fourier coefficient
by a complex number. Thus, frequency-selective fading and phase
distortion is more readily counteracted. The advantage here is that
frequency domain equalization using FFTs requires less computation
than conventional time-domain equalization. Accordingly, many
current vehicle modules like BCMs are computationally capable of
performing SC-FDMA. One benefit here is stable data transmission
and improved error rates over current implementations of PLC.
[0039] After the prior discussion of underlying communication
network technologies, embodiments will now be described in greater
detail. FIG. 3 is a simplified schematic block diagram of a power
line communication (PLC) system 300 in accordance with various
embodiments. PLC system 300 includes a DC power line 120. As
previously mentioned, current DC power line communication are
symmetric in nature (i.e., master and node have identical
capabilities). However most of the LIN buses in the vehicle's
electrical architecture are driven by a small subset of ECUs that
drive multiple LIN buses. For example, a body control module (BCM)
is an example of a LIN master that drives multiple LIN buses (e.g.,
16 or more in some BCMs). Such scenarios call for asymmetric design
where the LIN master is much more computationally capable than the
end nodes. Adding the fact that most of these LIN masters are also
powered by multiple power lines (such as, for example, 8 power
lines in the case of some BCMs) then the master transceiver becomes
a Multiple Input/Multiple Output (MIMO) receiver that can increase
reliability and robustness of the different LIN networks it drives
by diversifying its transmission over the different paths and
different frequencies. According to some embodiments, the nodes can
be populated with the common narrow band LIN transceivers (shown in
FIG. 3 as seven transceivers 312, 314, 316, 318, 320, 322, and 324)
that keep the overall cost of the system compatible with the wiring
costs and existing LIN topologies in currently manufactured
automobiles.
[0040] PLC system 300 can be viewed as a communication system that
has many input and outputs. System 300 includes power lines 120
connected to a power source 110, a ground network 302, and various
loads (not shown) within the vehicle. System 300 includes a vehicle
module 130-1 configured as a LIN master. Vehicle module 130-1 may
be a master module to various narrow band transceivers 312-324,
which may be configured to control various aspects of vehicle 100
such as, for example, lights, sensors, locks, motors, etc. Although
seven transceivers 312-324 are shown, is should be appreciated that
system 300 may include any number of transceivers. Transceivers
312-324 may be any one or more of vehicle modules 130-2 . . .
130-N.
[0041] Referring again to FIG. 2 in conjunction with FIG. 3,
according to one embodiment, vehicle module 130-1 is configured as
a LIN master node and includes a master PLC processor 240-1. PLC
master processor 240-1 is configured to perform various processing
steps of embodiments described herein. Master PLC processor 240-1
is in direct communication with power lines 120 via multiple input
and output channels 310. Input and output channels 310 connect PLC
master processor 240-1 to power lines 120 (as shown in FIG. 2).
Although depicted as a single I/O, input and output channels 310
can have any number of output leads (typically 8, 16, etc.).
[0042] According to embodiments, PLC master processor 240-1 is a
vehicle module (e.g., any one or more of vehicle modules 130-1 . .
. 130-N). Vehicle module 130-1 may be, for example, a BCM
functioning as a main computer in a vehicle cabin. In most modern
automobile power distribution architectures, signals are
communicable across all sub-systems in the vehicle power
distribution system. That is to say, a continuity test would
indicate that all vehicle components, vehicle modules, etc., are
connected together in some way via the power distribution system.
In one embodiment, input and output channels 310 contain 8 (or
more) wires for positive power communication with transceivers
312-324. For example, all of input and output channels 310 may be
12 V positive input power lines. The number and voltage of input
and output channels 310 can vary by application.
[0043] In an exemplary I/O where vehicle module 130-1 is configured
as a LIN master, vehicle module includes 8 inputs and outputs,
there are potentially 8 different channels of communication by
which the system may transmit data using the multiple frequency
channel communication (MIMO) protocol.
[0044] Vehicle module 130-1 as depicted in FIG. 3 can communicate
data to multiple LIN networks (e.g., any of vehicle modules 130-2 .
. . 130-N). For example, vehicle module 130-1 may be configured as
a LIN master to LIN transceivers 312-314. LIN transceivers 312-324
are all connected either directly or indirectly to one another and
to vehicle module 130-1.
[0045] Accordingly, in one embodiment, LIN transceivers 312-324 may
be connected, either directly or indirectly, to any number of the
LIN lines (input and output channels 310) operatively connected to
vehicle module 130-1. For example, one transceiver 312 could be a
sunroof controller, transceiver 314 could be an auxiliary alarm
sensor, and transceiver 316 could be a rain/light sensing module.
Accordingly, if vehicle module 130-1 sends a signal on a frequency
subcarrier f.sub.1 intended for only one of the three transceivers
(the sunroof transceiver 312), the signal is simultaneously sent to
all three transceivers 312, 314, and 316. If, at the same time the
transmission is sent, it begins to rain and rain sensing module 316
transmits a signal intended for receipt by vehicle module 130-1,
this may cause interference to the signal transmission intended for
sunroof transceiver 312. The inverse may also be true, where a
signal intended to transmit to vehicle module 130-1 indicative of
rain may not be heard by vehicle module 130-1 because of
interference by the signal sent to transceiver 312.
[0046] According to embodiments of the present disclosure, vehicle
module 130-1 is configured to transmit data to one or more of the
plurality of vehicle modules (transceivers) 312-324 via SC-FDMA
combined with one of two selectable protocols: a multiple frequency
channel communication protocol (that implements frequency hopping)
and a multiple input multiple output (MIMO) communication protocol
(that tests various signal paths and picks the most optimal
channel(s) based on a test signal response).
[0047] The first of the two selectable protocols includes frequency
hopping with the multiple frequency channel communication protocol.
With this technique, master PLC processor 240-1 can transmit data
using one or more sub-carrier frequencies that are not harmonics of
the main carrier frequency. By signal hopping, the processor can
simultaneously transmit data across the same power lines (e.g.,
powerlines 120) without mutual or unilateral interference.
[0048] According to another embodiment, interference can be avoided
using the second independent technique, referred to herein as the
MIMO communication protocol. Using the MIMO protocol, vehicle
module 130-1 simultaneously transmits the same signal on different
channels with the different frequencies.
[0049] In one aspect, master PLC processor 240-1 is configured to
transmit the data using both of the multiple frequency channel
communication protocol and the MIMO communication protocol, and a
user (e.g., an OEM or other manufacturer) can select the one of the
two selectable protocols.
[0050] According to one or more embodiments of the present
disclosure, any number of vehicle modules 130-1 . . . 110-N may be
a LIN master PLC processor that is configured to transmit data
using both of the MIMO communication protocol and the multiple
frequency channel communication protocol. Many current vehicle
modules (e.g., a BCM) are computationally suited for performing
narrowband communication like SC-FDMA implemented through the MIMO
communications and multiple frequency channel communication
protocols, as described herein.
[0051] Each of the two selectable protocols will now be considered
in greater detail, beginning first with the MIMO communication
protocol. Referring again to FIG. 3, when selectively configured to
implement the MIMO protocol, vehicle module 130-1 tests several
possible paths for signal transmission and picks one or more of the
best transmission paths (of channels 310) through which the signal
is transmitted. Master processor 240-1 then selects at least one
power line channel of channels 310 based on an observed system
response to a test signal transmitted on each of the power line
channels.
[0052] For example, in one exemplary embodiment, master PLC
processor 240-1 transmits a test signal on two or more channels 310
directly connected to master PLC processor 240-1. A test signal may
be any type of suitable test signal know in the art for testing
data transmission system response. The test signal may be
configurable by an end user to evaluate various signal paths
according to any predetermined test criterion. For example, as
shown in FIG. 3, the test signal could test channels associated
with all three of signal paths A, B, and C to determine the best
possible power line data channel for transmission to transceiver
316. The best possible path is implementation-specific and user
selected based on a desired system response characteristic.
According to embodiments, PLC master processor 240-1 observes the
system response to the test signal(s) transmitted, and selects one
or more power line channels A, B, and C from the tested channels
310 based on the system responses of the test signal. Accordingly,
PLC master processor 240-1 will transmit the data to one or more of
the plurality of vehicle modules 130-1 . . . 130-N via the at least
one selected power line channel.
[0053] The criterion by which master PLC processor 240-1 selects
the one or more channels for data transmission can vary by
application. In one aspect, the master module is configured with
both the physical layer and software layer for implementing any
number of user-selected options for selecting communication
channels for transmission. For example, master PLC processor 240-1
can be configured for PLC selective to the MIMO communication
protocol, where an end user (e.g., an automotive manufacturer
implementing system 300 in an automobile) programs the criterion by
which PLC master processor 240-1 selects one or more channels for
data transmission. In one embodiment, master PLC processor 240-1 is
configurable to select the at least one power line among channels
310 based on a predetermined range of signal attenuations. In
another aspect, master PLC processor 240-1 selects the shortest
attenuation of all system responses subsequent to sending the test
signal through channels 310.
[0054] In another embodiment, master PLC processor 240-1 is
configured to select the power line(s) or route for data
transmission based on signal strength by comparing the system
response to the test signal to a predetermined range of signal
amplitudes. In the present example, master PLC processor 240-1
selects the channel having the highest amplitude among the received
system responses. In another aspect, a particular signal strength
is optimal for an application, and the master PLC selects an
amplitude that falls within the predetermined range of signal
amplitudes that could be considered optimal for that
application.
[0055] Although any number of criteria for power line selection and
configurations are contemplated, one aspect of exemplary
embodiments is that the physical layer and the software layer
necessary for user selection are present for the desired system
response to be changeable by a user. Accordingly, the user may
select the criterion by which the one or more power lines are
selected from channels 310. In one aspect, the user selects the
criterion via a software interface configured to customize master
PLC processor 240-1. Pre-determined ranges of amplitude,
attenuation, etc., are omitted in the present exemplary
embodiments. It is appreciated that particular ranges of criteria
by which a communication channel may be selected by master PLC
processor 240-1 are application-specific.
[0056] Now considering the second selectable protocol according to
another exemplary embodiment, master PLC processor 240-1 is also
configured to transmit the data using the multiple frequency
channel communication protocol by frequency hopping on two or more
frequency channels operating on the same power line. As briefly
explained above, all power lines in modem vehicle power
distribution architectures are connected in some aspect. Therefore,
interference is possible in the power distribution system from any
operable system connected to the power distribution network. For
example, a vehicle power distribution system may experience very
short narrow interference in time and in frequency due to an
intermittent power signal or response such as operation of the
window wiper motors. The system may not be able to transmit
anything on a particular interfering frequency (e.g., 5 MHz) when
the wipers are in operation. Since current PLC systems operate on a
fixed carrier frequency for each vehicle module (transceiver), the
system may transmit to a vehicle module using a signal carrier
operating at the same 5 MHz frequency, or a harmonic of the main 5
MHz frequency. In this example there is possibility that recipient
won't hear the transmission due to interference from the 5 MHz
wiper controller.
[0057] According to one exemplary embodiment of the present
disclosure, vehicle module 130-1 may select several frequencies
that would avoid interference with the main carrier frequency and
all harmonics of the main frequency that would still interfere with
the transmission. For any signals to transmit to transceivers 312,
314, and 316 without interruption using the same sub-carrier
frequency f.sub.1 (still using the previous example of 5 MHz), the
signals must be sent spaced apart in time with respect to each of
the multiple transmissions. A transmission of the same signal must
be sent on the same sub-carrier frequency f.sub.1 at intervals
separated by two seconds (or some other predetermined interval of
time) to avoid interference. For example, to avoid the 5 MHz
frequency interference, master PLC processor 240-1 may transmit at
a carrier frequency of 3 MHz, then hop to 6 MHz, 9 MHz, 12 MHz,
etc. Each of the transmissions are also separated by a
predetermined interval of time, which allows flexibility in signal
transmission where an identical signal can transmit across the same
channel to two different recipients receiving different carrier
frequencies.
[0058] FIG. 4 depicts a graph 400 showing a plurality of signals
408, 410, 412, 414, 416, 418, 420, and 422 transmitted using a
multiple frequency channel communication protocol, in accordance
with various embodiments. FIG. 4 will be discussed in conjunction
with FIG. 3. Referring briefly to FIG. 4, graph 400 illustrates
signals 408-422 with respect to frequency 402 (in the x-axis), time
404 (in the y-axis), and power 406 (in the z-axis). Master PLC
processor 240-1 is configured to transmit data (e.g., signals
408-422) using the multiple frequency channel communication
protocol by frequency hopping on two or more frequency channels 402
operating on the same power line, according to exemplary
embodiments. For the sake of explanation, all of signals 408-422
are operating on the same power line 120 (as shown in FIG. 3).
[0059] Referring now to FIG. 4, (and still keeping with the 5 MHz
example), data signal 408 may transmit on a 5 MHz carrier signal.
It is notable that signal 408 is spaced in time with all other
signals (that is, no other transmission is sent at the same time as
data signal 408). Accordingly, there exists spacing in time between
all signal transmissions. Referring again to the windshield wiper
motor example, if the windshield wiper motors are operating on the
same 5 MHz frequency as data signal 408, master PLC processor 240-1
cannot transmit anything else at the same time at 5 MHz. Stated in
another way, data signal 408 may become lost (unheard) or may
experience another data error due to interference if transmitted at
5 MHz. With multiple other frequencies to select from, master PLC
processor 240-1 can select, for example 7 MHz (data signal 410), 11
MHz (data signal 416), etc.
[0060] Data communications on the PLC also transmit on harmonics of
the main transmission frequency. For example, if we transmit signal
408 at a carrier frequency of 5 MHz, any other signals at the same
time must not be 5 MHz or a multiple (harmonic) of 5 MHz. As shown
in graph 400, signal 418 is transmitted using a carrier signal of
10 MHz, which interferes with signal 408 if simultaneously
transmitted. Accordingly, if master PLC processor 240-1 hops to 6
MHz as a carrier signal frequency, the system avoids interference
with main 5 MHz frequency (and all of its harmonics at 10, 15, 20
MHz, etc.).
[0061] Continuing with the same example, if master PLC processor
240-1 transmits to transceiver 322 (as shown in FIG. 3) at 10 MHz,
the transmission 418 is spaced in time from the signal 408 at the
interfering frequency (and thus it does not interfere because of
the separation in time). Accordingly, master PLC processor 240-1 is
configured to transmit the data on a different frequency of the two
or more frequency channels at a predetermined time interval between
each of the frequency channels. A predetermined time interval may
be, for example, any value such as 10 ms, 100 ms, 1 sec, 2 sec,
etc. Any other signals that would be multiples of 5 (e.g., 15 MHz,
20 MHz, etc.) must also be time delineated. But if we jump to 6
MHz, it is not a harmonic of 5 MHz, master PLC processor 240-1 has
avoided this interference from simultaneous transmission on power
lines 120.
[0062] For example, signal 420 and 418 are transmitted
simultaneously to transceivers 322 and 324 using the same power
line 120. However, since signal 420 is transmitted at 6 MHz and
signal 418 is transmitted at 10 MHz, there is no interference
between the signals. Accordingly, master PLC processor 240-1
selects a pseudo-orthogonal frequency sequence of the two or more
frequency channels, where the frequency sequence includes a main
transmission frequency for signal 420 and one or more frequencies
that are not harmonics of the main transmission frequency to
simultaneously transmit signal 422 such as, for example, 10
MHz.
[0063] Without frequency hopping, as demonstrated above, system 300
has an option of transmitting on the same frequency but at
different times. However, avoidance of interfering signals
operating at the same frequency may not be consistently effective
because the interfering signal may not be intermittent (i.e., it
may be continuous) which means the time-divided transmissions are
not guaranteed to be heard by the receiving module. Although there
is difference in time shown between signals 408 and 420, there
exists an implication that there may not be interference between
the two signals. But what may not be known to master PLC processor
240-1 is the exact nature of the possible interfering signal (e.g.,
its tendency to be repeating, continuous, the period of repeating,
etc.). To overcome this shortcoming, the multiple frequency channel
communication protocol jumps in time and jumps in frequency (and
thus, is pseudo-orthogonal).
[0064] Embodiments of the present disclosure provide power line
communication of data over multiple LIN /CAN buses in automobiles.
In aspects described herein, multiple power line channels can be
dynamically chosen by a master vehicle module based on one or more
user-configured criteria to add an additional layer of data
integrity that fits all kinds of operational scenarios and
equipment configurations. Exemplary embodiments also provide for
transmission of data over multiple frequency bands, which adds an
additional layer of flexibility and data error mitigation for
robust and reliable data transmission over power lines. Moreover,
the data is driven by a single master PLC processor having
processing capability commensurate with vehicle modules currently
in use, which makes widespread adoption both practical and cost
effective.
[0065] While the above disclosure has been described with reference
to exemplary embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from its scope.
In addition, many modifications may be made to adapt a particular
situation or material to the teachings of the disclosure without
departing from the essential scope thereof. Therefore, it is
intended that the present disclosure not be limited to the
particular embodiments disclosed, but will include all embodiments
falling within the scope thereof
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