U.S. patent application number 12/986945 was filed with the patent office on 2012-01-19 for power line communication networks and methods employing multiple widebands.
Invention is credited to Nils Hakan Fouren, Jonathan Ephraim David Hurwitz, Juan Carlos Riveiro.
Application Number | 20120014459 12/986945 |
Document ID | / |
Family ID | 35456000 |
Filed Date | 2012-01-19 |
United States Patent
Application |
20120014459 |
Kind Code |
A1 |
Riveiro; Juan Carlos ; et
al. |
January 19, 2012 |
Power Line Communication Networks and Methods employing Multiple
Widebands
Abstract
Systems and methods for communicating over a power line are
configured to substantially simultaneously communicate over a
plurality of wideband frequency ranges. Signals may be communicated
two or from a communication node at two different frequencies
simultaneously. These signals may be exchanged with different nodes
and/or include independent data. In some embodiments, some of the
wideband frequency ranges are above 30 MHz.
Inventors: |
Riveiro; Juan Carlos;
(Barcelona, ES) ; Fouren; Nils Hakan; (Barcelona,
ES) ; Hurwitz; Jonathan Ephraim David; (Edinburgh,
GB) |
Family ID: |
35456000 |
Appl. No.: |
12/986945 |
Filed: |
January 7, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12484754 |
Jun 15, 2009 |
7877078 |
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12986945 |
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11467141 |
Aug 24, 2006 |
7899436 |
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12484754 |
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Current U.S.
Class: |
375/257 |
Current CPC
Class: |
H04B 3/542 20130101;
H04B 2203/5495 20130101; H04B 2203/5416 20130101 |
Class at
Publication: |
375/257 |
International
Class: |
H04B 3/00 20060101
H04B003/00; H04L 25/00 20060101 H04L025/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 3, 2005 |
EP |
EP 05 256 179.2 |
Claims
1. A communication network comprising: three communication nodes,
each including a first analog filter, each configured to
communicate simultaneously and independently over a power line with
the other two communication nodes using a plurality of widebands
wherein a high band of the plurality of widebands has a minimum
frequency greater than 30 MHz.
2. The communication network of claim 1 wherein a low band of the
plurality of widebands has a maximum frequency of about 30 MHz.
3. The communication network of claim 2 wherein the first analog
filter of each communication node comprises a low pass filter.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 12/484,754 filed on Jun. 15, 2009 and titled
"Power Line Communication Networks and Methods employing Multiple
Widebands" which is a continuation of U.S. patent application Ser.
No. 11/467,141 filed on Aug. 24, 2006 and titled "Multi-Wideband
Communications over Power Lines" which claims benefit of and
priority to European Patent Application EP 05 256 179.2, entitled
"Power line Communication Device and Method," filed Oct. 3, 2005
under 35 U.S.C. 119. The disclosures of the above patent
applications are incorporated by reference herein.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The present invention relates to systems and methods for
power line communication and in particular, systems and methods for
wideband power line communication.
[0004] 2. Related Art
[0005] With the growing use of digital content (e.g. MP3 audio,
MPEG4 video and digital photographs) there is a widely recognised
need to improve digital communication systems. Power line
communication (PLC) is a technology that encodes data in a signal
and transmits the signal on existing electricity power lines in a
band of frequencies that are not used for supplying electricity.
Accordingly, PLC leverages the ubiquity of existing electricity
networks to provide extensive network coverage. Furthermore, since
PLC enables data to be accessed from conventional power-outlets, no
new wiring needs to be installed in a building (or different parts
of a building). Accordingly, PLC offers the additional advantage of
reduced installation costs.
[0006] Referring to FIG. 1, a household 10 typically has a
distributed mains wiring system consisting of one or more ring
mains, several stubs and some distribution back to a junction box
12. For the sake of example, let the household 10 comprise four
rooms 14, 16, 18 and 20. Every room 14-20 may have a different
number of outlets and other mains connections. For example, room 14
may have only one connection 22, room 16 may have two connections
24, 26, room 18 may have three connections 28, 30, 32 and room 20
may have six connections 34, 36, 38, 40, 42, 44.
[0007] Accordingly, there are a variety of distances and paths
between different power outlets in the household 10. In particular,
the outlets most closely located to each other are those on
multi-plug strips, and the outlets furthest away from each other
are those on the ends of stubs of different ring mains (e.g. power
outlets in the garden shed and the attic). Communication between
these furthest outlets typically pass through junction box 12.
Nonetheless, the majority of outlets associated with a particular
application (e.g. Home Cinema) are located relatively close
together.
[0008] Because the channel capacity of a power line and connectors
attenuates according to, amongst other features, the frequency of a
transmitted signal, current generation PLC systems have been
developed to transmit signals at relatively low frequencies (i.e.
below 30 MHz) and thereby obtain suitable transmission distances.
However, the use of such low transmission frequencies limits the
maximum data throughput obtainable by PLC systems.
[0009] The processes of receiving analog signals and injecting
modulated signals are treated differently by different PLC
standards. Current approaches perform some analog conditioning to
the signal-path (e.g. low-pass filtering for anti-aliasing or
smoothing, or AC coupling to remove the low-frequency [<<1
KHz] high voltage content of the electricity mains). However, there
are no analog systems available for combining two or more broadband
PLC technologies that can work simultaneously.
[0010] A number of power line communication standards have been
defined. These include the Homeplug 1.0/1.1 standards, the Homeplug
AV standard, the CEPCA standard and the Digital Home Standard.
[0011] In common with most communication systems, one of the main
problems with prior art PLC systems is obtaining high throughput
and wide coverage at reasonable implementation cost, whilst
maintaining compatibility with existing technologies. Although a
few PLC systems that provide transmission rates of hundreds of
megabits per second are currently on the market, these systems have
high implementation costs as they employ high bps/Hz modulation
schemes (i.e. approximately 10 bps/Hz) which require high accuracy
data converters, extremely linear interface electronics and
increase the cost of the digital implementation due to the
computational complexity of the modulation.
[0012] There is, therefore, a need for improved PLC systems that
overcome the above and other problems.
SUMMARY
[0013] Various embodiments include systems and methods of
communicating over a power line by simultaneously sending and/or
receiving data over a plurality of wideband frequency ranges.
Various embodiments include a power line communication network
comprising at least one power line communication device configured
to use a plurality of wideband frequency ranges.
[0014] Some embodiments include a system for communicating over a
power line comprising a device for communicating over a power line,
systems for connecting to the power line, and systems for
transmitting data from the device to appropriate applications or
transmitting data from the applications to the device.
[0015] In some embodiments, the power line communication device is
configured to improve the throughput/coverage/cost performance
trade-off of a power line network, when compared with
current-generation PLC networks, by spreading the transmission of
data into a plurality of independent wideband frequency bands that
can be operated simultaneously and independently.
[0016] Furthermore, the power line communication device also
optionally facilitates inter-operability by using one or more of
the frequency bands to facilitate communication with nodes
employing previous power line technologies. In this way, the power
line communication device provides a way of creating a scalable
implementation of a network where nodes of previous technologies
work, without loss of performance, together with new-generation
power line technologies.
[0017] More particularly, the power line communication device can
enable the use of frequencies above 30 MHz whilst maintaining
compatibility with current worldwide EMC regulations and standards.
This is achieved by using a signal of frequency less than 30 MHz
(as currently used by the power line standard and/or regulations)
and at least one other signal of frequency greater than 30 MHz
without compromising the performance of any of the signals due to
interference.
[0018] The result is a new PLC system that facilitates
interoperability with a pre-existing power line communication
technology within a wideband (currently in the frequency range of 1
MHz to 30 MHz) and provides the ability to extend the system into
new significantly higher frequency widebands (e.g., frequencies
between 30 MHz and 1 GHz) to improve the overall throughput of the
resulting communication system while simplifying the implementation
of any single given wideband.
[0019] The power line communication device comprises a network
interface device that employs an analog signal separating device
(e.g., analog filter) to separate the paths of different wideband
signals received from the power line before converting them to
their digital representation. The analog signal separating device
also separates the paths of different wideband signals to be
transmitted on the power line (after their conversion from their
digital representation). The network interface device optionally
employs TDMA (time division multiple access) and/or FDMA (frequency
division multiple access) as a scheme for enabling co-existence,
synchronisation and/or bi-directional transmission.
[0020] The analog signal separating device is configured from block
elements comprising discrete and/or integrated electronic
components and the natural characteristics of the wiring and/or
printed circuit board traces used to interconnect said
components.
[0021] In some embodiments, the power line communication device is
employed in a system that is configured to be expandable to provide
greater overall bandwidth, but with widely differing injected power
levels in the different frequency ranges, and/or to coexist and be
inter-operate with other pre-existing technologies on the same
network.
[0022] In various embodiments, each of the pre-existing and
new-generation power line technologies is configured to implement
different modulation schemes (e.g. OFDM, CDMA (code division
multiple access) and/or OWDM (orthogonal wavelet domain
modulation)), either alone or in combination). Depending on its
channel state, the power line communication device can send data
through any or all of the widebands. Furthermore, depending on its
network function, the power line communication device can
distribute the data from a single source or mesh it together with
data repeated from another node on the network.
[0023] In various embodiments, each node on the power line
communication network is an apparatus that integrates the analog
signal separating device and modem converters (e.g. DFE (Digital
Front End), MAC (Media Access Control), etc.) as part of the power
line network interface device; and an application such as a
computer, mass storage device, display device, speaker, DVD
(Digital Versatile Disc) player, PVR (Personal Video Recorder),
etc.; and/or an interface to connect an application such as a
digital audio interface, digital video interface, analog audio
interface, analog video interface, Ethernet interface,
IEEE1394/Firewire/iLink interface, a USB (Universal Serial Bus)
interface, and/or the like.
[0024] In some embodiments, the power line communication device is
configured to use a signal (in line with the current standards and
injected power regulations) of frequency less than about 30 MHz and
at least one other signal of frequency greater than 30 MHz without
compromising the performance of any of the signals due to
interference. This feature can enable the power line communication
device to increase throughput whilst enabling interoperability with
previous PLC technologies.
[0025] An advantage of using a low frequency band is the
possibility for higher coverage (e.g., communication over greater
distances) than that achievable with a high frequency band, due to
the greater injected power allowed by the regulations and the lower
channel attenuation. An advantage of using a high band is the
higher throughput achievable due to the greater available
bandwidth.
[0026] In some embodiments, the power line communication device is
configured to exploit the natural topology of power line networks
in a home, wherein a group of related devices and sockets are
typically clustered close to each other (e.g. plasma screen, DVD
player and speakers in a living room) and other clusters of devices
and sockets are clustered elsewhere (e.g. desktop printer, scanner
and ADSL router in a home office). Such household topologies can
benefit from the high throughput short-range coverage provided by
the high band (which is simultaneously and independently available
within each of the clusters) whilst the low band can be used to
carry the majority of data communications between the clusters. It
will also be appreciated that some communication nodes may benefit
from communications on both bands.
[0027] In some embodiments, the parallel use of multiple widebands
enables the use of different injected power levels, receiver
sensitivities, transmission times, symbol lengths and modulation
techniques to optimise the performance and cost of each wideband,
leading to a better cost performance solution even though it is
necessary to provide more than one analog and digital front-end.
Part of the implementation cost advantage arises from the ability
to reduce the bps/Hz in each wideband, but still maintain
throughput performance because of the additional bandwidth
available. This effect non-linearly compensates for the cost of
implementing more than one wideband communication technology.
Furthermore, the reduced coverage of the high band(s) is offset by
the parallel use of the low band (with its greater allowable
injected power). For instance, in various embodiments, the power
line communication device may be used to provide Gbit/s performance
at a lower cost than current 200 Mbps systems, by using lower
bps/Hz modulation schemes (i.e. approximately 5 bps/Hz rather than
10 bps/Hz) over multiple widebands.
[0028] In various embodiments, a network interface device is
configured to employ analog signal separation and include multiple
analog front-ends. The use of analog signal separation, based on
frequency, enables each wideband technology to optionally operate
independently, and may include one or more of the following
features:
[0029] (a) The network interface device is configured for
independent performance optimization of the analog to digital
converters (ADCs), digital to analog converters (DACs) and PGA or
line drivers employed in processing the signals from a given
frequency band, wherein the optimisation is performed for the
required bandwidth, linearity and dynamic features of the frequency
band and optimised for the power levels required to match EMC
regulations and/or coverage of the frequency band;
[0030] (b) The network interface device is configured for the power
line communication device to maintain compatibility and
inter-operability with existing standards using one of the
frequency bands, whilst exploiting independently (and without
causing prohibitive interference to) another frequency band for
additional communication (for example, the Homeplug AV standard
which uses frequencies in the range of 2 MHz-28 MHz could work
simultaneously with another standard that uses frequencies greater
than 30 MHz);
[0031] (c) The network interface device is configured to increases
the capacity of the power line communication device by allowing the
inclusion of additional widebands that do not need to use the same
modulation technology, but can use modulation technologies that
best match the new frequency bands' power line channel
characteristics; and
[0032] (d) The network interface device is configured to allow
different widebands to operate without synchronisation to or
dependence on other widebands.
[0033] In various embodiments, the power line communication device
is also configured to allow other network technologies to be
layered independently on top of it, for example:
[0034] (a) combinations of data from different bands at various
different communication levels whether in the digital front-end,
the MAC layer or the application layer;
[0035] (b) using notches in the modulation scheme to limit
emissions of certain frequencies within one of the analog defined
wideband frequencies;
[0036] (c) using repeaters in a node to re-transmit on the same or
a different frequency band;
[0037] (d) using a range of modulation schemes such as OFDM, CDMA
and/or ODWM; and/or
[0038] (e) forming point-to-point, point-to-multipoint and or
multipoint-to-multipoint communication patterns.
[0039] In some embodiments, the network interface device can
combine and partition data communicated across different paths to
maximise performance, coexistence and interoperability whilst
minimizing system cost.
[0040] Various embodiments of the invention include a method
comprising receiving digital data form one or more applications,
encoding a first part of the digital data into a first signal
within a first wideband frequency range, at least part of the first
wideband frequency range being less than 30 MHz, encoding a second
part of the digital data into a second signal within a second
wideband frequency range, at least part of the second wideband
frequency range being greater than 30 MHz, combining the first
signal and the second signal to generate a combined signal, and
sending the combined signal over a power line.
[0041] Various embodiments of the invention include a method
comprising receiving a signal over a power line, separating the
received signal into a first signal component in a first wideband
frequency range and a second signal component in a second wideband
frequency range, each of the first wideband frequency range and the
second wideband frequency range being at least 10 MHz wide,
separately processing the first signal component and the second
signal component to extract digital data, and providing the digital
data to one or more applications.
[0042] Various embodiments of the invention include a communication
network comprising a first communication node configured to
communicate using a first wideband frequency range at least 10 MHz
wide and a second wideband frequency range at least 5 MHz wide, a
second communication node configured to communicate with the first
communication node over a power line by simultaneously using both
the first wideband frequency range and the second wideband
frequency range.
[0043] Various embodiments of the invention include a communication
device comprising a coupling configured to communicate data over a
power line, a first part of the data being communicated using a
first wideband frequency range and a second part of the data being
communicated using a second wideband frequency range separate from
the first wideband frequency range, the first part of the data
being independent from the second part of the data, first logic
configured to process the first part of the data, and second logic
configured to process the second part of the data.
[0044] Various embodiments of the invention include a communication
network comprising a first communication node configured to
communicate using a first wideband frequency range, a second
communication node configured to communicate using a second
wideband frequency range separate from the first wideband frequency
range, and a third communication node configured to simultaneously
and independently receive communication from the first
communication node over a power line using the first wideband
frequency range and from the second communication node over the
power line using the second wideband frequency range.
[0045] Various embodiments of the invention include a method
comprising communicating first data between a first communication
node and a second communication node over a power line, using a
first wideband frequency range, and communicating second data
between the first communication node and a third communication node
over the power line, using a second wideband frequency range
separate from the first wideband frequency range, the first data
and the second data being communicated simultaneously.
[0046] Various embodiments of the invention include a method
comprising sending a first communication from a first communication
node over a power line using a first wideband frequency range, the
first communication including data configured to identify a second
communication node configured to communicate in the first wideband
frequency range, receiving a response to the first communication
from the second communication node, sending a second communication
from the first communication node over the power line using a
second wideband frequency range, the second communication including
data configured to identify a third communication node configured
to communicate in the second wideband frequency range, receiving a
response to the second communication from the third communication
node, and determining a communication strategy based on the
response to the first communication and the response to the second
communication.
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] Multiple embodiments of the invention will now be described
by way of example only with reference to the accompanying Figures
in which:
[0048] FIG. 1 is a block diagram of a prior art residence;
[0049] FIG. 2A is a block diagram of an exemplary network
comprising a plurality of nodes, some of which have multiple
wide-band capabilities, according to various embodiments;
[0050] FIG. 2B is a block diagram of the exemplary network of FIG.
2A, depicting two simultaneous, bi-directional communication links
therein, according to various embodiments;
[0051] FIG. 2C is a block diagram of the exemplary network of FIG.
2A, depicting three simultaneous communication links therein,
according to various embodiments;
[0052] FIG. 2D is a block diagram of a first stage of a one packet
data transmission procedure implemented on the network of FIG. 2A,
according to various embodiments;
[0053] FIG. 2E is a block diagram of a second stage of the one
packet data transmission procedure shown in FIG. 2D, according to
various embodiments;
[0054] FIG. 3 is a block diagram of the hardware architecture of a
modem in a power line communication device, according to various
embodiments;
[0055] FIG. 4A is a block diagram of signal paths in a single
coupling unit prior art power line transmission system, according
to various embodiments;
[0056] FIG. 4B is a block diagram of signal paths in a dual
coupling unit prior art power line transmission system, according
to various embodiments;
[0057] FIG. 4C is a block diagram of signal paths in a first
embodiment of the power line communication device;
[0058] FIG. 4D is a block diagram of signal paths in a second
embodiment of the power line communication device;
[0059] FIG. 4E is a block diagram of signal paths in a third
embodiment of the power line communication device;
[0060] FIG. 4F is a block diagram of signal paths in a fourth
embodiment of the power line communication device;
[0061] FIG. 5A is a block diagram of a first integrated circuit
embodiment of the power line communication device;
[0062] FIG. 5B is a block diagram of an alternatively partitioned
second integrated circuit embodiment of the power line
communication device;
[0063] FIG. 5C is a block diagram of a further alternatively
partitioned third integrated circuit embodiment of the power line
communication device;
[0064] FIG. 6A is a circuit diagram of an exemplary capacitive
coupling unit used in the power line communication device,
according to various embodiments;
[0065] FIG. 6B is a circuit diagram of an exemplary inductive
coupling unit used in the power line communication device,
according to various embodiments;
[0066] FIG. 7A is an exemplary power transmission spectrum of three
power line technologies, according to various embodiments;
[0067] FIG. 7B depicts the frequency characteristics of an
exemplary set of analog filters for use in separating the widebands
used by the three power line technologies depicted in FIG. 7A,
according to various embodiments;
[0068] FIG. 7C shows the signal isolation provided by a second
analog filter Filt.sub.B (shown in FIG. 7B) to the Tech.sub.B
signal (shown in FIG. 7A), according to various embodiments;
[0069] FIG. 8A is a block diagram of a household with a simple
initial installation of the power line communication network of the
third aspect of the invention, according to various
embodiments;
[0070] FIG. 8B is a block diagram of a household with a more
complex installation of the power line communication network,
according to various embodiments;
[0071] FIG. 9 illustrates a method by which one communication node
can discover other communication nodes on a network using different
wideband frequency ranges, according to various embodiments;
[0072] FIG. 10 illustrates a method in which a first communication
node communicates simultaneously with both a second communication
node and a third communication node, according to various
embodiments;
[0073] FIG. 11 illustrates a method in which a communication node
receives simultaneous signals using at least two different
widebands, according to various embodiments; and
[0074] FIG. 12 illustrates a method in which a communication node
sends simultaneous signals using at least two different widebands,
according to various embodiments.
DETAILED DESCRIPTION
[0075] For the sake of clarity, the term "power line" will be used
herein to refer to low voltage household mains distribution cabling
(typically 100-240 V AC power) or any other distributed
electrically conductive cabling (i.e. AC or DC), that is capable of
passing power to appliances connected to it. Furthermore, the term
"power line technology" will be used herein to refer to a
specification that when implemented as a series of network
interface devices connected to a power line, enables the devices to
bi-directionally communicate with each other using signals
superimposed on the power distribution signal already present on
the power line.
[0076] The term "network interface device" will be used herein to
describe an apparatus that implements either fully or partially, a
communications technology, such as a power line technology, to
enable the apparatus to communicate with other devices connected to
the same network (such as a power line), regardless of whether or
not the apparatus is integrated with other apparatuses or functions
within a single enclosure. For the sake of clarity, a device
connected to a power line network will be generically known herein
as a "node".
[0077] The term "coverage" will herein be used to refer to the
maximum distance between two nodes at which data transmitted
therebetween is still detectable by either node. In addition, the
term "throughput" will be understood to represent the rate at which
nodes send or receive data on a network.
[0078] For the sake of clarity, in terms of explanation of
operation of the power line communication device around current
power line technologies, a wideband frequency band used in the
power line communication device whose frequency of less than about
30 MHz, will be known herein as a "low band". Similarly, a wideband
frequency band(s) used in the power line communication device whose
frequency is greater than about 30 MHz will be known herein as
"high band(s)".
[0079] For completeness and since the present invention relates to
wideband communication, the term "wideband" will be used herein to
refer to a frequency band or range used by a power line technology
signal, characterised by having a bandwidth of greater than, or
equal to, 5 MHz from the first (lowest) frequency to the last
(highest) frequency of the band irrespective of the presence of
notches. However, in various embodiments, wideband may have
bandwidths of at least 7, 10, 12, 15, 20, 100 or 250 MHz.
Similarly, the term "narrowband" will be used to refer to a
frequency band used by a power line technology signal,
characterised by having a bandwidth of less than 5 MHz. A wideband
may include many different carrier channels used to convey data.
For example, in various embodiments, widebands include more than
25, 50, 100 or 200 data channels.
[0080] The term "transmission time" is herein used to describe the
maximum amount of time it takes to transmit a single co-existent
message. The transmission time includes, but is not limited to, a
start of transmission marker time (if any), a synchronisation time
(if any), a channel access resolution time (if any), a negotiation
time (if any), a message transmission time, an acknowledge
transmission time (if any) and an end of transmission marker time
(if any).
[0081] The term "notch" will be used herein to refer to a frequency
band where the energy level of a power line technology signal has
been deliberately reduced to prevent interference with other users
of the spectrum (whether on or off the power line). Notches are
characterized by having a narrower bandwidth than the power line
technology signal itself and are generally implemented by digital
or analog signal separating device within a single digital signal
processing block or analog front end.
[0082] For the sake of clarity, the term "sub-band" will be used
herein to refer to a frequency band where a power line technology
signal characteristic differs from the characteristics of the power
line technology signal in the remainder of the signal's bandwidth.
Such differences can include the optional or mandatory presence of
the sub-band, the signal power level of the sub-band and the
directionality of the sub-band. Sub-bands are characterized by
having a narrower bandwidth than the power line technology signal
itself. The use of overlapping sub-bands in OFDM enables notches to
be created, wherein a sub-band is disabled if the reception of the
sub-band is heavily impaired or the sub-band can interfere with
another service. Furthermore, OWDM can simplify the notching out of
carriers due to its lower side lobes.
[0083] For the sake of simplicity, the term "transmitter signal
path" will be used to refer to the path of a signal transmitted
from an apparatus to the power line. Similarly, the term "receiver
signal path" will be used to refer to the path of a signal received
by an apparatus from a power line. On a related note, it may not be
necessary to perform the isolation on both the receiver and
transmitter signal paths (depending on the specifications of the
analog components and the modulation techniques employed
therein).
[0084] For the sake of clarity, the power line communication device
of the present invention will be referred to herein at times as an
"improved power line communication device". Similarly, the network
interface device of the improved power line communication device
will be referred to herein as an "improved network interface
device". Finally, the power line communication network comprising
nodes that are improved communication devices will be known herein
at times as an "improved power line communication network".
[0085] The term "separate," as used herein with respect to
widebands, is to characterize widebands that do not use, except
incidentally, the same frequencies for communication data or
commands. Widebands may be separate but interleaved, e.g.,
overlapping.
[0086] The term "simultaneously" is used herein with respect to
communicating data to indicate that at least part of first data or
commands are communicated using a first wideband at the same time
as at least part of second data or commands are communicated using
a second wideband. Simultaneous transmission is contrasted with
systems that alternate or interleave the use of frequencies, one
after the other or hopping from one to the other.
[0087] The term "independent" is used herein with respect to data
transmitted to indicate that data transmitted using one wideband
does not depend on data simultaneously transmitted using another
wide band. Independent data transmission can include, for example,
data sent to or received from different locations. Data in which
alternative bits are transmitted using different frequencies is not
independent because the bits are dependent on each other to form a
useful byte.
[0088] It will be appreciated that the specific network and other
examples described in these sections are used for illustrative
purposes only. In particular, the examples described in these
sections should in no way be construed as limiting the improved
power line communication device.
[0089] Some embodiments of the improved power line communication
network comprise a plurality of nodes of which some employ a
network interface device that enables simultaneous and independent
communication over two or more widebands, to similar multi-wideband
nodes or conventional nodes. A first wideband optionally comprises
frequencies of less than 30 MHz, in line with the current standards
and injected power levels (and will herein be known as a low band)
and the other wideband(s) comprise frequencies of greater than 30
MHz (and will herein be known as high band(s)). Alternatively, both
a first and second wideband may comprise frequencies greater than
30 MHz. This enables power line technologies to be optimised for
each of the widebands, so that the trade-off between cost, coverage
and throughput will be superior to that achieved by a purely
mono-wideband approach.
[0090] In particular, the modulation schemes for each technology
used within the improved power line communication network can be
optimised for cost. For instance it may not be necessary to use a
particularly high modulation density (bps/Hz) in the low band to
enhance throughput because the low band can work in parallel with
the inherently high throughput high band(s).
[0091] The improved power line communication network provides
inter-operability with prior art power line technologies by also
supporting communication between multi-wideband nodes and
mono-wideband nodes (that use one of the power line technologies
supported in the low band or high band(s) and communicate at
frequencies in the low or high band(s).
[0092] The improved network interface device may be part of an
external modem apparatus or embedded within another apparatus (e.g.
computer, TV etc.). However, regardless of the manner in which an
improved network interface device is included within a node, the
device remains physically connected to electrically conductive
cabling (that passes AC or DC power) and is capable of transmitting
digital data across the cabling using either or all of the low and
high bands.
[0093] In accordance with current regulatory standards, low band
signals may be transmitted with a power spectral density of
approximately up to -50 dBm/Hz whereas high band signals may only
be transmitted with a power spectral density that causes emissions
in this frequency band to be lower than -80 dBm/Hz. Accordingly,
signals in the low band may be transmitted with a power spectral
density approximately one thousand times greater than signals in
the high band. Consequently, if signals in both of these bands were
to be transmitted simultaneously, without using some form of analog
frequency isolation, the dynamic range and voltage compliancy
requirements of the high band signals would be significantly
increased.
[0094] However, the potential for interference or saturation of a
lower power signal may be even more problematic. In particular, if
one of the bands is used to receive a line-attenuated signal whose
power level is close to the noise on the power line (i.e. -150
dBm), while at the same time, the other band is used to transmit a
signal at its maximum allowable transmission power, the isolation
required to prevent the signals from the two bands from interfering
with each other would be approximately 100 dB. However, this is
beyond the current state of the art analog implementations and
would have high implementation costs.
[0095] In summary the isolation required to effectively allow
simultaneous and independent communication of high and low bands
falls into three main categories:
[0096] (1) isolation to prevent the strength of a signal received
over the network in one wideband from saturating the receiver of
the other wideband;
[0097] (2) isolation to prevent the transmitter of one band from
interfering with the reception of another band; and
[0098] (3) isolation to prevent the degradation of the transmitter
for one band when another band is being transmitted.
[0099] In view of the above, the improved network interface device
employs an analog signal separation device to isolate the paths
from the power line connection to an apparatus; to data-converters
for each wideband. One of the most efficient ways of providing this
isolation is by high-pass filtering or band-pass filtering high
band signals, whilst minimising out-of band signals in the low band
(using high linearity components and possibly analog low-pass
smoothing or anti-aliasing).
[0100] Signals in the high band and the low band can use the same
or different modulation techniques (e.g. OFDM, CDMA and/or ODWM) or
time division schemes to facilitate co-existence and/or
bi-directional communication. In one possible scenario, the low
band could employ a modulation scheme that is inter-operable with
one of the existing power line modem standards or proposals, whilst
the high band is used for performance expansion beyond previous
standards. Data and/or control can be passed through one or both of
the widebands simultaneously and via a plurality of nodes in the
form of a repeater (e.g., relay) network.
[0101] There are many different ways of implementing the improved
power line communication device. For example, the improved power
line communication device may be implemented on one or more
integrated circuits (whether dedicated to the modem function or as
part of an application system on a chip), and in combination with
the characteristics of passive components and interconnects.
However, the implementation of the analog signal separating device
to separate the low band and high band(s)) employs a combination of
the components in the different signal paths, whether passive or
active, integrated or discrete. In particular, it is possible for
the widebands:
[0102] (a) to share part of their paths (e.g. through a coupling
unit); or
[0103] (b) to be joined only at the power line; and/or
[0104] (c) to be at opposite ends of the apparatus.
[0105] It is also possible to expand the improved power line
communication device to communicate on more than two widebands.
Similarly, it is also possible for the widebands to overlap
slightly if required, and to be different in frequency ranges or
bandwidths to those cited in the specific description.
[0106] Referring to FIG. 2A, a network 50 that represents the
improved power line communication network, comprises a plurality of
nodes 54-76. Some of the nodes comprise the improved power line
communication device and accordingly implement more than one PLC
technology. Nodes that do not include the improved network
interface device can only implement one PLC technology. For the
sake of simplicity, nodes that can only implement one PLC
technology will be known herein as "mono-wideband nodes".
Similarly, nodes that can implement more than one technology will
be known herein as "multi-wideband nodes".
[0107] Three different PLC technologies are employed for
communication on the network, namely Tech.sub.A, Tech.sub.B and
Tech.sub.C. Nodes 54 and 76 comprise the improved network interface
device and are capable of implementing PLC technologies Tech.sub.A
and Tech.sub.B. Nodes 58 and 66 comprise the improved network
interface device and are capable of implementing PLC technologies
Tech.sub.B and Tech.sub.C. Finally, nodes 60 and 68 comprise the
improved network interface device and are optionally capable of
implementing all three PLC technologies.
[0108] The remaining nodes (namely nodes 56, 62, 64, 72 and 74) do
not comprise the improved network interface device and thus can
only implement one of the PLC technologies. In particular, nodes 62
and 70 implement PLC technology Tech.sub.A only, nodes 56 and 72
implement PLC technology Tech.sub.B only, and nodes 64 and 74
implement PLC technology Tech.sub.C only. Optionally, all of the
communication between the nodes on the network 50 takes place
through a common power line 52.
[0109] In some embodiments, the improved power line communication
network supports communication between nodes that implement
different PLC technologies. In contrast, prior art PLC systems can
only support communication between nodes that implement identical
PLC technologies (e.g. nodes 56 and 72), even if the nodes in
question co-exist on a network with nodes that implement other PLC
technologies (e.g. nodes 64 and 74).
[0110] FIG. 2B shows two simultaneous, bi-directional and
non-interfering communication links in the network 50 of FIG. 2A. A
first communication link 80 is a point-to-point communication link
between nodes 54 and 68 which simultaneously uses the high band and
low band to enable simultaneous communication of both Tech.sub.A
and Tech.sub.B messages between the two nodes.
[0111] It should be noted that whilst node 68 is optionally capable
of implementing all three technologies (i.e. Tech.sub.A, Tech.sub.B
and Tech.sub.C) only the Tech.sub.A and Tech.sub.B capabilities of
node 68 are used in the first communication link 80. Furthermore,
it should be noted that the first communication link 80 can
re-distribute data from the Tech.sub.A and Tech.sub.B technologies
across the high band and the low band in accordance with the
current network characteristics (e.g. channel impairments).
[0112] A second communication link 82 connects nodes 68, 58, 60, 74
and 64. Since nodes 64 and 74 are only capable of implementing PLC
technology Tech.sub.C, the second communication link 82 only
supports communications of the Tech.sub.C technology.
[0113] The presence of the two communication links 80 and 82 allows
nodes 68, 58, 60, 74 and 64 to establish communication (through the
second communication link 82) at the same time that node 68 is
communicating with 56 (through the first communication link 80). In
other words, the network arrangement depicted in FIG. 2B, enables
two simultaneous and concurrent communications to be performed,
wherein the first communication link 80 enables dynamic data
transmission and reception using technologies Tech.sub.A and/or
Tech.sub.B and the second communication link 82 enables dynamic
data transmission and reception using technology Tech.sub.C.
[0114] FIG. 2C shows three concurrent and simultaneous
communication links 84, 86 and 88 in the network 50 of FIG. 2A. The
first communication link 84 provides a bi-directional
point-to-multipoint connection between node 54 and nodes 68 and 70.
Since node 70 is only capable of implementing technology
Tech.sub.A, the first communication link only supports
communications of the Tech.sub.A technology. Meanwhile a second
communication link 86 enables communication between nodes 56 and 72
of technology Tech.sub.B with technology Tech.sub.A, using a
co-existence strategy such as Time Division Multiple Access (TDMA)
(i.e. a multiple access technique where only one transmitter
transmits on a particular channel at any given time).
[0115] Finally, a third communication link 88 supports
communication of Tech.sub.C, wherein these communications are
conducted in a different wideband that does not interfere with the
other communication links.
[0116] Referring to FIG. 2D, let there be a first communication
link 90 between nodes 68, 58 and 60 of the network 50 depicted in
FIG. 2A. The first communication link 50 is bi-directional and
supports communication of Tech.sub.B and Tech.sub.C. Furthermore,
let there be a simultaneous second communication link 92 between
nodes 70 and 62 of the same network 50. The second communication
link 92 supports communication of Tech.sub.A.
[0117] For the sake of example, let there be a message originating
in node 58 that to be distributed to the nodes of the network 50.
Nodes such as 68, 60 and 66 that support Tech.sub.B and Tech.sub.C,
can demodulate and receive a message from node 58. However, the
remaining nodes on the network 50 cannot receive the message. To
solve this problem, a two-stage communication process is
implemented in which:
[0118] (i) in the first stage, the message is transmitted from node
58 to 68, using PLC technologies Tech.sub.B and Tech.sub.C; and
[0119] (ii) in the second stage, the message is re-transmitted
(e.g., relayed) by node 68, using its technology capabilities, so
that optionally all of the nodes on the network 50 can receive and
demodulate the message.
[0120] Repeaters can also be used to increase the coverage of a
given technology (when a node can detect its neighbouring node, but
not further nodes thereafter).
[0121] FIG. 2E is a block diagram of a second stage of the one
packet data transmission procedure shown in FIG. 2D. This second
stage optionally includes a broadcast made simultaneously in more
than one wideband. As such, the broadcast may include more that one
communication standard.
[0122] Referring to FIG. 3, a modem 80 in an improved network
interface device comprises N blocks 82A-82N corresponding to each
of the PLC technologies supported by the node. In other words,
block 82A corresponds with the Tech.sub.A technology, block 82B
corresponds with the Tech.sub.B technology, and so on, until block
82N, which corresponds with the Tech.sub.N technology.
[0123] Each block 82A-82N comprises the first (PHY) and second
(MAC) layers of the OSI (Open Systems Interconnection) stack for
each technology. For example, the block 82A comprises the blocks
PHY.sub.A and MAC.sub.A. Similarly, the block 82B comprises the
blocks PHY.sub.B and MAC.sub.B. The modem 80 further comprises a
data distribution block 84, which distributes data amongst the
blocks 80A and 80N in accordance with the technology of the signal
and current network traffic characteristics.
[0124] When used for transmission, signals from each technology
supported by a node are processed by an analog filter bank (not
shown). The operation of the analog filter bank will be described
in more detail later. The processed signals 86 are forwarded to the
data distribution block 84 for distribution amongst the blocks
82A-82N. The outputs from the blocks 82A-82N are combined in a
coupling/decoupling stage 88 from which they are injected into a
power line 90.
[0125] When used for receiving a signal from the power line 90, the
coupling/decoupling stage 88 decouples the component signals for
each supported PLC technology. The decoupled signals are processed
through blocks 82A-82N and forwarded through the data distribution
block 84 to the appropriate applications running on the node.
[0126] Each of the PHY blocks (PHY.sub.A-PHY.sub.N) may have a
feedback signal 92A-92N which provides information regarding the
usage of each of the technology signal paths. This information is
used by the data distribution block 84 to redistribute the data
flow amongst the N available blocks 82A-82N. It should also be
noted that parts of the MAC and PHY blocks (PHY.sub.A-PHY.sub.N)
and (MAC.sub.A-MAC.sub.N) may be capable of sharing resources.
[0127] Referring to FIG. 4A, in a first form of a prior art power
line transmission system, a power line 100 is connected to a single
coupling unit 102, which has high-pass transmission characteristics
to enable the rejection of the AC line frequency of the power line
100. The coupling unit 102 is, in turn, connected to receiver and
transmitter paths 104, 106, which are isolated during half duplex
phases using an RX/TX switch 108.
[0128] The receiver path 104 typically comprises a band-limiting
anti-aliasing filter 110, a programmable gain amplifier (PGA) 112,
and an ADC 114. The resulting digital signal 116 is then
demodulated 118. The anti-aliasing filter 110 may be in a different
order and may be partially or completely provided by the bandwidth
of the PGA.
[0129] The transmitter path 106 typically comprises a line driver
120 (which may or may not be capable of operating in high impedance
mode) and a band-limiting smoothing filter 122. The band-limiting
smoothing filter 122 limits the power of harmonics (in the
out-of-band range) in the analog signal (the harmonics being
produced by the operation of a DAC 124 on a received digital signal
126 that had previously been modulated 128). It will be realised
that part of the modulation and demodulation schemes 118, 128 could
also be performed in the analog domain.
[0130] Referring to FIG. 4B a slightly different form of a prior
art single wideband system employs separate transmitter and
receiver coupling units 130, 132. A TX/RX switch is not required in
this form of the prior art power line transmission system, as
either the impedance of the line driver 120 does not significantly
represent an extra impedance load to the power line 100 or the line
driver 120 itself is capable of going into a high impedance
mode.
[0131] Referring to FIG. 4C, the improved network interface device
comprises two or more analog front-ends separated into two low band
analog paths LB.sub.1 and LB.sub.2 and two high band paths HB.sub.1
and HB.sub.2, by coupling units 142, 148, 154 and 160
respectively.
[0132] The analog filtering characteristics of the different paths
(including the coupling units 140-146 and the active components)
are designed to pass the signal of a given band whilst rejecting
the signals of the other bands. The modulation schemes of each
technology 152, 154 may be the same or different, as may be the
demodulation schemes 148, 150.
[0133] Referring to FIG. 4D in a second embodiment of the improved
network interface device there are two coupling units 166, 176,
wherein coupling unit 166 is used for low band communication and
coupling unit 176 is used for high band communication. In addition
to the optimisation of the low band paths (167-171 and 172-175) and
the high band paths (177-181 and 182-185) for the power, frequency
and modulation schemes of different PLC technologies, the coupling
units 166, 176 can be optimised to have different pass-frequency
characteristics.
[0134] Referring to FIG. 4E, in a third embodiment of the improved
network interface device, there are two coupling units 186 and 190,
wherein coupling unit 186 is used for reception and coupling unit
190 is used for transmission. However, each high band path (188-191
and 203-206) is isolated from the low band paths (192-195 and
197-201) by deliberately inserted filters 187, 202 with high pass
or band pass characteristics.
[0135] FIG. 4F shows a fourth embodiment of the improved network
interface device, applied to two different wideband technologies as
in FIG. 4E. Whilst there are many possible other combinations, it
is not necessary for there to be separate paths and converters for
the high band paths and low band paths in either the receiver or
transmitter, as communications in one direction may benefit more
from the improved network interface device than communications in
the other direction.
[0136] The improved network interface device comprises one coupling
unit for transmission 218 and one for reception 208. The high band
is isolated from the low-band on the receiver path, by deliberately
inserted filters 209 with high-pass or band-pass characteristics.
However, the transmitter modulation schemes are combined in the
digital domain 222A, 222B and then passed through a very high
performance DAC (digital to analog converter) 221, smoothing filter
220 and line driver 219.
[0137] Referring to FIG. 5A, an exemplary integrated circuit 250
implementation of the improved network interface device comprises
two analog front ends AFE.sub.A, AFE.sub.B for the two widebands of
the improved power line communication device. The exemplary
integrated circuit 250 also comprises a logic element 226
configured to implement the different power line modem technologies
(including DFE and MAC) and provide a digital interface to the next
stage application 228 in the device.
[0138] The high band analog front end (AFE.sub.B) contains high
band converters 230, 232 and active interface electronics (i.e. a
PGA 234 and line driver 236) and connects to the power line via a
coupling unit along path 238. The low band analog front end
(AFE.sub.A) comprises low band converters 240, 242 and active
interface electronics (i.e. a PGA 244 and line driver 246) and
connects to the power line via a coupling unit along path 248.
[0139] A digital representation of the signal to be sent on the low
band and high band is produced in the logic element 226 and is
present at interfaces 250, 252 to the analog front ends AFE.sub.A,
AFE.sub.B.
[0140] Referring to FIG. 5B, in an alternative integration
partition 300 of the integrated circuit implementation of the
improved network interface device, there are two integrated
circuits, namely a digital modem integrated circuit 302 and an
analog modem integrated circuit 304 containing the two analog front
ends AFE.sub.A, AFE.sub.B. The analog modem integrated circuit 304
may be configured in several parts, as illustrated in FIG. 5B, or
alternatively as a single component.
[0141] Referring to FIG. 5C, in another integration partition 400
of the integrated circuit implementation of the improved network
interface device, the analog front end of each wideband is split
into data converters Conv.sub.A, Conv.sub.B and interface circuits
I/Face.sub.A, I/Face.sub.B. In this case, the converters
Conv.sub.A, Conv.sub.B are integrated with the digital logic 401 of
the power line modem in one integrated circuit 402 while the higher
frequency current/voltage interface circuitry is provided in
another integrated circuit 404.
[0142] It will be appreciated that there are numerous other
possibilities including the embedding of all or part of the active
electronics within other devices in the system, or the use of
discrete blocks for various blocks.
[0143] As discussed elsewhere herein, a coupling unit can have
frequency characteristics. Referring to FIG. 6A, a capacitive
coupling unit 500 comprises X1 type capacitors 502 that are used to
couple a signal source 504 (via an isolating transformer 506) onto
a power line 508. In this case, the impedances of the transformer
506, capacitors 502, signal source 504 and the power line 508
determine the frequency response of the capacitive coupling unit
500.
[0144] Referring to FIG. 6B, an inductive coupling unit 520
comprises a signal transformer 522 that inductively couples a
signal 524 in tandem with a Y1 type capacitor 526. The inductive
coupling unit 520 is roughly equivalent to the capacitive coupling
unit 500 (depicted in FIG. 6A), with the respective impedances of
the transformer 522, capacitor 526, signal source 524 and power
line 528 determining the frequency response of the inductive
coupling unit 520.
[0145] Furthermore, a low-pass filtered version of the power line
508, 528 can be used within the improved network interface device
to provide a power supply. It is also possible to implement higher
order filters in the coupling units with more passive components.
Nonetheless, it will be appreciated that it is possible to employ
many other types of coupling unit (e.g. optical coupling units) in
the power line network interface device.
[0146] FIGS. 7A to 7C illustrates the exemplary frequency spectra
of a number of different power line technologies, and demonstrates
how an analog signal separating device could be used to separate
the signals of a given technology (from the signals of the other
technologies) into a particular signal path.
Referring to FIG. 7A, a first technology Tech.sub.A has a
transmission power P.sub.A and a wide-band 540 delimited by
frequencies f.sub.A1 and f.sub.A2. The wide-band 540 has internal
notches 542 to comply with EMC regulations. A second technology
Tech.sub.B has a transmission power of P.sub.B and a wide-band 544
delimited by frequencies f.sub.B1 and f.sub.B2. The wide-band 544
also has a notch 546 to comply with EMC (Electromagnetic
Compatibility) regulations. It should be noted that f.sub.B1 may be
greater than f.sub.A2 to avoid band-overlapping. Finally, a third
technology Tech.sub.N, has transmission power P.sub.N and a
wide-band 548 delimited by frequencies f.sub.N1 and f.sub.N2. The
wide-band 548 also has a notch 550 to comply with regulations.
Referring to FIG. 7B a first, second and third analog filter
(namely Filt.sub.A, Filt.sub.B and Filt.sub.N respectively)
respectively isolate the signals from each of Tech.sub.A,
Tech.sub.B and Tech.sub.N, from the signals from the other
technologies. The analog filter characteristics are applicable to
the transmitter and/or the receiver of each technology within a
node.
[0147] The first analog filter Filt.sub.A is defined by passband
start and end frequencies f.sub.A3, f.sub.A4. Similarly the second
analog filter Filt.sub.B is defined by passband start and end
frequencies f.sub.B3 and f.sub.B4. Finally, the third analog filter
Filt.sub.N is defined by passband start and end frequencies
f.sub.N3 and f.sub.N4.
[0148] In one embodiment, the start of at least one of the
passbands of the analog signal separating device of the power line
communication device is between 1 MHz and 30 MHz, and is at least
10 MHz in width. Optionally, at least one of the other widebands
includes signals at a frequency greater than 30, 40, 50, 75, 100,
200 or 500 MHz, and optionally less than 1 GHz. The difference
between the passband and stopband for any one of the elements of
the analog signal separating device may be more than 6 dB.
[0149] It should be noted that it is possible for different analog
filters to overlap (e.g. f.sub.A4>f.sub.B3), or not to overlap
(e.g. f.sub.B4<f.sub.N3). It should also be noted that it is not
necessary for the passbands of all of the analog filters to have
the same transmission power, attenuation functions, or other
characteristics. The product of the analog filter characteristic
and the modulation scheme of a given PLC technology determines the
effectiveness of the isolation by each analog filter. The absolute
transmission of the filters in their respective passbands is less
important than the ratio of passband to stopband, as any
attenuation differences in these filters can often be compensated
for with more injected power at the pre-filter stage and/or
increased receiver sensitivity.
[0150] FIG. 7C shows an example of the isolation provided by the
second analog filter Filt.sub.B to the Tech.sub.B signal. In use,
the second analog filter passes a signal Path.sub.B that is the
product of the transmission power (PF.sub.B) of then passband of
the second analog filter and the transmission power (P.sub.B) of
the Tech.sub.B signal. The signals of the other technologies
(Tech.sub.A and Tech.sub.N) are attenuated by the stopband of
Filt.sub.B to a power level PF.sub.N that is sufficiently less than
PF.sub.B to ensure that they do not significantly interfere with
the Path.sub.B signal.
[0151] In some embodiments, the improved power line communication
network includes the ability to provide increased throughput as the
number of nodes increase in the network. In particular, such
increased throughput demand typically coincides with an increased
number of nodes, since more data needs to be transmitted when
multiple devices share the network.
[0152] FIG. 8A shows a simple initial installation of a single
service, in this case IPTV (internet protocol television) delivered
to the home 600 via a DSL connection 602, which is distributed
(using the improved power line communication network) from the DSL
modem 602 in the office to a TV set 604 in the living room. Since
the distance between the DSL modem 602 and the TV set 604 is
comparatively long, the connection C1 therebetween predominantly
uses the low band due to its inherently greater coverage. The
bandwidth provided by the low band is sufficient for the TV set
because only a single TV channel is transmitted.
[0153] As an improved power line communication network grows (i.e.
more nodes are added to it) the average distances between nodes
tends to decrease. When a very complex situation is installed like
that depicted in FIG. 8B (showing a complex in-home multimedia
network with multiple simultaneous video and audio streams),
connections C2-C7 are predominantly implemented using the high band
(due to its greater throughput) over the relatively short distances
present. Low band connections C8, C9, will still be in use when
their efficiency is higher than using multiple hops of high band
links. In addition, many connections (e.g. C10) will be served by
communication using both bands.
[0154] In use, a node on the network will typically discover the
other nodes on the power line through some form of synchronization
that is usually defined within the power line technology used in
one of the bands. The node will also identify the technology
capabilities and virtual network membership of the detected nodes,
to determine what communication will be possible and/or allowable
(for instance, whilst a detected node may physically have certain
technology capabilities, these may be impaired by interference or
restricted in use). Having identified the physically possible and
allowable communications, the sending node will decide the best
path for sending/receiving data, based on factors such as the type
of data to be communicated, how it is ranked in the QoS (quality of
service) and the available channel capacity.
[0155] FIG. 9 illustrates a method by which one communication node
can discover other communication nodes on a network using different
wideband frequency ranges. In a send step 910, a first
communication is sent from a first communication node over a power
line using a first wideband frequency range, the first
communication including data configured to identify a second
communication node configured to communicate in the first wideband
frequency range. This first communication is configured to solicit
a response from other communication nodes, such as the second
communication node, that are configured to communicate over the
first wideband frequency.
[0156] In a receive step 920, a response to the first communication
is received from the second communication node.
[0157] In a send step 930, a second communication is sent from the
first communication node over the power line using a second
wideband frequency range, the second communication including data
configured to identify a third communication node configured to
communicate in the second wideband frequency range. This second
communication is configured to solicit a response from other
communication nodes, such as the third communication node, that are
configured to communicate over the second wideband frequency.
[0158] In a receive step 940, a response to the second
communication is received from the third communication node. If the
second communication node is further configured to communicate
using the second wideband, then receive step 940 may include
receiving communications from both the second and third
communication nodes.
[0159] In a determine step 950, a communication strategy based on
the response to the first communication and the response to the
second communication. This determination may include selections of
widebands or standards to use. This determination may include a
strategy for communication between the third and second
communication nodes, e.g., should the communication be direct or
should the first communication node function as a relay. In some
embodiments, Send Steps 910 and 930 include using different
standards in addition to or as an alternative to using different
widebands.
[0160] In an optional communicate further step communication is
executed according to the determined communication strategy.
[0161] FIG. 10 illustrates a method in which a first communication
node communicates simultaneously with both a second communication
node and a third communication node. The communication is
optionally independent. The first communication node optionally
operates as a relay between the second communication node and the
third communication node.
[0162] In a first communication step 1010, first data is
communicated between a first communication node and a second
communication node over a power line, using a first wideband
frequency range. In a second communication step 1020, second data
is communicated between the first communication node and a third
communication node over the power line, using a second wideband
frequency range separate from the first wideband frequency range,
the first data and the second data being communicated
simultaneously.
[0163] The method illustrated in FIG. 10 is optionally employed
where the second communication node functions as both the second
and the third communication node. In these embodiments a first part
of data can be sent using the first wideband frequency and a second
part of data can be sent using the second wideband frequency. In
these embodiments, the use of the two different wideband
frequencies is optionally configured to maximize total data
bandwidth.
[0164] FIG. 11 illustrates a method in which a communication node
receives simultaneous signals using at least two different
widebands. Data encoded in these signals is optionally independent
and may be received from different communication nodes on a
network. The data may also be transmitted and/or decoded using
different communication standards.
[0165] In a receive first signal step 1110, a signal is received
over a power line. This signal includes encoded data. The encoding
may include any of the various methods known for encoding data on a
time dependent signal.
[0166] In a separate component step 1120, a first component of the
signal, in a first wideband frequency range, is separated from a
second component of the signal, in a second wideband frequency
range. In various embodiments, each of the first wideband frequency
range and the second wideband frequency range are at least 5, 7,
10, 12, 15, 20, 100, and/or 200 MHz wide. For example in one
embodiment, the first wideband frequency range is at least 10 MHz
wide and the second wideband frequency range is at least 5 MHz
wide. In one embodiment, the first wideband frequency range is at
least 10 MHz wide and the second wideband frequency range is at
least 200 MHz wide. In some embodiments, the separation of signal
components is performed using analog bandpass filters. For example,
one bandpass filter may be configured to isolate the first wideband
frequency range and another bandpass filter may be configured to
isolate the second wideband frequency range.
[0167] In a process step 1130, the first signal component and the
second signal component, separated in separate component step 1120,
are each separately processed. This processing is typically
preformed in parallel. For example, one signal component may be
processed using low band analog path LB.sub.1 and the other signal
component may be processed using high band path HB.sub.1, Low band
analog path LB.sub.1 and high band path HB.sub.1 optionally share
one or more component. Process step 1130 results in two sets of
digital data.
[0168] In a provide step 1140, the two sets of digital data are
provided to one or more applications. The two sets of digital data
may be used independently.
[0169] FIG. 12 illustrates a method in which a communication node
sends simultaneous signals using at least two different widebands.
Data encoded in these signals in optionally independent and may be
intended for different communication nodes on a network. The data
may be transmitted and/or encoded using different communication
standards.
[0170] In a receive data step 1210, digital data is received from
one or more applications. This data is optionally independent. In
an encode step 1220, a first part of the digital data is encoded
into a first signal within a first wideband frequency range, at
least part of the first wideband frequency range is optionally less
than 30 MHz. This encoding may be performed using, for example, low
band analog path LB.sub.2.
[0171] In an encode step 1230, a second part of the digital data is
encoded into a second signal within a second wideband frequency
range, at least part of the second wideband frequency range is
optionally greater than 30 MHz. This encoding may be performed
using, for example, high band path and HB.sub.2. Encode Step 1230
and Encode Step 1220 may be performed in parallel.
[0172] In a combine step 1240, the first signal and the second
signals are combined to generate a combined signal. This step is
optionally performed using Tx Coupling 196, or HB Tx Coupling 154
and LB Tx Coupling 160. For example, using HB Tx Coupling 154 and
LB Tx Coupling 160 the combination may occur as both signals are
coupled to a power line.
[0173] In a send step 1250, the combined signal is sent over a
power line. Different parts of the combined signal may be sent
simultaneously and may be intended for different destinations.
Several embodiments are specifically illustrated and/or described
herein. However, it will be appreciated that modifications and
variations are covered by the above teachings and within the scope
of the appended claims without departing from the spirit and
intended scope thereof. For example, the techniques described
herein may be in used in household, industrial and/or vehicle power
systems. Further various elements illustrated and discussed herein
may be embodied in software (stored on computer readable media),
firmware, and/or hardware. These element forms are generally
referred to herein as "logic."
[0174] The embodiments discussed herein are illustrative of the
present invention. As these embodiments of the present invention
are described with reference to illustrations, various
modifications or adaptations of the methods and or specific
structures described may become apparent to those skilled in the
art. All such modifications, adaptations, or variations that rely
upon the teachings of the present invention, and through which
these teachings have advanced the art, are considered to be within
the spirit and scope of the present invention. Hence, these
descriptions and drawings should not be considered in a limiting
sense, as it is understood that the present invention is in no way
limited to only the embodiments illustrated.
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