U.S. patent application number 14/589017 was filed with the patent office on 2015-04-23 for phy payload over multiple tone masks using single tone mask phy header information.
The applicant listed for this patent is Texas Instruments Incorporated. Invention is credited to ANAND G. DABAK, IL HAN KIM, TARKESH PANDE, RAMANUJA VEDANTHAM, KUMARAN VIJAYASANKAR.
Application Number | 20150110163 14/589017 |
Document ID | / |
Family ID | 47293177 |
Filed Date | 2015-04-23 |
United States Patent
Application |
20150110163 |
Kind Code |
A1 |
VEDANTHAM; RAMANUJA ; et
al. |
April 23, 2015 |
PHY PAYLOAD OVER MULTIPLE TONE MASKS USING SINGLE TONE MASK PHY
HEADER INFORMATION
Abstract
A method of communications includes compiling a data frame for
physical layer (PHY) by a first communications device at a first
communications node on a network. The data frame includes a single
tone PHY header portion and a data payload portion in a set of
tones including at least one tone having a frequency different from
a frequency of the single tone. The PHY header portion includes
tone mask identification information identifying the set of tones.
The first communications device transmits the data frame over the
powerline to a second communications device at a second
communications node on the powerline. The second communications
device receives the data frame, and decodes the data payload using
the tone mask identification information in the PHY header
portion.
Inventors: |
VEDANTHAM; RAMANUJA; (ALLEN,
TX) ; DABAK; ANAND G.; (PLANO, TX) ; PANDE;
TARKESH; (RICHARDSON, TX) ; KIM; IL HAN;
(ALLEN, TX) ; VIJAYASANKAR; KUMARAN; (ALLEN,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Texas Instruments Incorporated |
Dallas |
TX |
US |
|
|
Family ID: |
47293177 |
Appl. No.: |
14/589017 |
Filed: |
January 5, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13493268 |
Jun 11, 2012 |
8958464 |
|
|
14589017 |
|
|
|
|
61495003 |
Jun 9, 2011 |
|
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Current U.S.
Class: |
375/222 ;
375/257 |
Current CPC
Class: |
H04L 5/0007 20130101;
H04L 27/2602 20130101; H04L 5/0037 20130101; H04B 3/542 20130101;
H04L 5/0094 20130101; H04L 27/2613 20130101; H04B 2203/5445
20130101; H04L 69/22 20130101; H04B 2203/5408 20130101; H04L
27/2666 20130101 |
Class at
Publication: |
375/222 ;
375/257 |
International
Class: |
H04B 3/54 20060101
H04B003/54; H04L 27/26 20060101 H04L027/26; H04L 29/06 20060101
H04L029/06 |
Claims
1-25. (canceled)
26. A method of communications, comprising: compiling a data frame
for a physical layer (PHY) by a first communications device at a
first communications node, said data frame including a single tone
PHY header portion and a data payload portion in a set of tones
including at least one tone having a frequency different from a
frequency of said single tone; wherein said PHY header portion
includes a tone mask field having tone mask identification
information identifying said set of tones; said first
communications device transmitting said data frame to a second
communications device at a second communications node, said second
communications device receiving said data frame, and said second
communications device decoding said data payload portion using said
tone mask identification information.
27. The method of claim 26, wherein said tone mask field represents
said data tone mask as a bit map only when a data tone mask (DTM)
field of said data frame is set to indicate said DTM.
28. The method of claim 26, wherein said tone mask identification
information is provided as an additional field added to a data
frame of a standard that supports multi-tone mask mode
operation.
29. The method of claim 28, wherein said additional field is in a
format comprising a first tone mask, first extension bit, a second
tone mask, second extension bit, wherein said additional field ends
as soon as one of said extension bits is set to 0.
30. The method of claim 26, wherein said set of tones for said data
payload are both at different frequencies when compared to said
frequency of said single tone.
31. A modem for communications at a first node on a communications
channel in a network including a second node, comprising: a
processor; wherein said processor is communicably coupled to a
memory which stores a frame compiling algorithm for compiling a
data frame including in a tone mask field within a PHY header
portion which represents a data tone mask as a bit map, said tone
mask field includes tone mask identification information
identifying a set of tones used for a data payload portion of said
data frame, wherein said processor is programmed to implement said
frame compiling algorithm, said frame compiling algorithm:
compiling said data frame including a single tone frame PHY header
portion and said data payload portion in a set of tones including
at least one tone having a frequency different from a frequency of
said single tone, wherein said PHY header portion includes said
tone mask identification information identifying said set of tones,
wherein said modem is configured for coupling to a transceiver to
provide said data frame to said transceiver so that said
transceiver transmits said data frame over said channel to said
second node.
32. The modem of claim 31, wherein said modem is formed on an
integrated circuit (IC) comprising a substrate having a
semiconductor surface, and wherein said processor comprises a
digital signal processor (DSP).
33. The modem of claim 31, wherein said tone mask field represents
said data tone mask as a bit map only when a data tone mask (DTM)
field of said data frame is set to indicate said DTM.
34. The modem of claim 31, wherein said tone mask identification
information is provided as an additional field added to a data
frame of a standard that supports multi-tone mask mode
operation.
35. The modem of claim 34, wherein said additional field is in a
format comprising a first tone mask, first extension bit, a second
tone mask, second extension bit, wherein said additional field ends
as soon as one of said extension bits is set to 0.
36. The modem of claim 31, wherein said set of tones for said data
payload are both at different frequencies when compared to said
frequency of said single tone.
37. A communications device, comprising: a memory which stores a
frame compiling algorithm, a modem, said modem comprising: a
processor communicably coupled to said memory, wherein said
processor is programmed to implement said frame compiling
algorithm, said frame compiling algorithm, comprising: compiling a
data frame including a single tone frame PHY header portion and a
data payload portion in a set of tones including at least one tone
having a frequency different from a frequency of said single tone,
wherein said PHY header portion having a tone mask field which
represents a data tone mask as a bit map, said tone mask field
includes tone mask identification information identifying said set
of tones used for said data payload portion, and a communications
transceiver communicably coupled to said modem for transmitting
said data frame over a channel to a receiving node.
38. The communications device of claim 37, wherein said modem is
formed on an integrated circuit (IC) comprising a substrate having
a semiconductor surface, and wherein said processor comprises a
digital signal processor (DSP).
39. The communications device of claim 37, wherein said tone mask
field represents said data tone mask as a bit map only when a data
tone mask (DTM) field of said data frame is set to indicate said
DTM.
40. The communications device of claim 37, wherein said tone mask
identification information is provided as an additional field added
to a data frame of a standard that supports multi-tone mask mode
operation.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Divisional of and claims priority to
U.S. patent application Ser. No. 13/493,268, filed Jun. 11, 2012
which claims the benefit of U.S. Provisional Application Ser. No.
61/495,003 entitled "PHY PAYLOAD TRANSMISSION OVER MULTIPLE TONE
MASKS USING SINGLE TONE MASK PHY HEADER INFORMATION" filed Jun. 9,
2011. Said applications are herein incorporated by reference in
their entireties.
FIELD
[0002] Disclosed embodiments relate generally to the field of
powerline communications, and more specifically to communication of
tone mask information between devices in powerline communications
networks.
BACKGROUND
[0003] Power line communications (PLC) include systems for
communicating data over the same medium (i.e., a wire or conductor)
that is also used to transmit electric power to residences,
buildings, and other premises. Once deployed, PLC systems may
enable a wide array of applications, including, for example,
automatic meter reading and load control (i.e., utility-type
applications), automotive uses (e.g., charging electric cars), home
automation (e.g., controlling appliances, lights, etc.), and/or
computer networking (e.g., Internet access), to name only a
few.
[0004] Current and next generation narrow band PLC are orthogonal
frequency division multiplexing (OFDM)-based (as opposed to
frequency shift keying (FSK)-based) in order to get higher network
throughput. OFDM uses multiple orthogonal subcarriers to transmit
data over frequency selective channels. A conventional OFDM
structure for a data frame includes a preamble, followed by a
physical layer (PHY) header, followed by a data payload. Examples
of OFDM-based PLC standards include IEEE P1901.2 and PoweRline
Intelligent Metering Evolution (PRIME).
[0005] In PLC networks, the system has the ability to communicate
in both low voltage (LV) powerlines as well as high voltage power
lines. When operating in a high-voltage powerline the system is
able to communicate with low-voltage powerlines. This means that
the receiver on the LV side must be able to detect the transmitted
signal after it has been severely attenuated as a result of going
through a medium voltage (MV)/LV transformer. The coupling
interface between the PLC device and the MV medium may be referred
to as a MV/LV crossing.
[0006] In PLC networks that have MV/LV crossings, data transmission
over the full FCC allowed frequency band may not be feasible due to
network conditions (e.g., noise) so that smaller frequency band
portions referred to as tone masks (or subbands) may be needed for
each particular MV/LV communication link. A tone map in contrast to
a tone mask refers to an allocation of power within a tone mask.
The tone mask can thus be considered to be a collection of tone
maps.
[0007] The receiving PLC device may be "listening" only on one tone
mask at a given time. Since the set of tone masks that provide
effective communications for a particular link may vary
link-to-link, the receiver may not be tuned to the proper set of
tone masks to decode the received frame. When nodes are unable to
decode the data payload sent over the tone masks indicated in the
received frame, such as indicated in the PHY header referred to as
the frame control header (FCH) in the case of the IEEE P1901.2
standard, the node will set their virtual carrier sensing (VCS) to
the EIFS value to account for the largest data payload size
transmission allowed in the network.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Reference will now be made to the accompanying drawings,
which are not necessarily drawn to scale, wherein:
[0009] FIG. 1 is a block diagram of a simplified PLC network
comprising different entities participating in PLC communications
using a powerline, that can benefit from disclosed embodiments.
[0010] FIG. 2A is a diagram of an example data frame for a PHY
including a PHY header portion that utilizes a single TM which
provides information about the set of TMs in which the data payload
will be transmitted, suitable for PLC communications, according to
an example embodiment.
[0011] FIG. 2B is a diagram of an example PHY header portion that
utilizes a single TM mask which provides information about the set
of TMs in which the data payload in the data frame will be
transmitted, according to an example embodiment.
[0012] FIG. 2C is a diagram of another example PHY header portion
that utilizes a single TM mask which provides information about the
set of TMs which the data payload in the data frame will be
transmitted, according to an example embodiment.
[0013] FIG. 3 is a block diagram schematic of a communication
device having a disclosed modem that implements disclosed data
frames for PHY including a PHY header portion that utilizes a
single TM which provides information about the set of TMs in which
the data payload of the data frame will be transmitted operation on
a PLC communication channel, according to an example
embodiment.
[0014] FIG. 4 is a flowchart for an example method for PLC
communications in a PLC network that includes using data frames
including a PHY header portion which utilizes a single TM which
provides information about the set of TMs in which the data payload
of the data frame will be transmitted, suitable for PLC
communications, according to an example embodiment.
DETAILED DESCRIPTION
[0015] Disclosed embodiments now will be described more fully
hereinafter with reference to the accompanying drawings. Such
embodiments may, however, be embodied in many different forms and
should not be construed as limited to the embodiments set forth
herein. Rather, these embodiments are provided so that this
disclosure will be thorough and complete, and will fully convey the
scope of this disclosure to those having ordinary skill in the art.
One having ordinary skill in the art may be able to use the various
disclosed embodiments and there equivalents. As used herein, the
term "couple" or "couples" is intended to mean either an indirect
or direct electrical connection, unless qualified as in
"communicably coupled" which includes wireless connections. Thus,
if a first device couples to a second device, that connection may
be through a direct electrical connection, or through an indirect
electrical connection via other devices and connections.
[0016] FIG. 1 is a block diagram of a simplified PLC network 100
comprising different entities participating in PLC communications
using a powerline 130, that can benefit from disclosed embodiments.
PLC network 100 includes a PLC data concentrator (or base node) 114
that may have a MV modem coupled to a MV powerline, and may
therefore communicate with the first PLC device 105 at one node in
the network and a second PLC device 110 at another node in the PLC
network 100.
[0017] Both PLC devices 105 and 110 may include LV modems coupled
to a shared powerline 130, or in another embodiment to different LV
power lines (e.g., separated by one or more transformers). First
PLC device 105 may receive packets from PLC data concentrator 114
using a first set of downlink subbands. In some cases,
communication conditions (e.g., noise, interference, etc.) may be
such that, from the perspective of PLC device 105, one or more of
the available downlink subbands may yield a better signal-to-noise
ratio than other downlink subbands. First PLC device 105 may also
transmit packets to PLC data concentrator 114 using a first set of
uplink subbands. Here, from the perspective of PLC data
concentrator 114, one or more of the available uplink subbands may
yield better a better signal-to-noise ratio. Also, because PLC data
concentrator 114 may receive transmissions from a plurality of PLC
devices, different sets of uplink subbands may be allocated to
these different devices to reduce contention and potential
collisions that may potentially negatively impact desired data
rates, etc.
[0018] Second PLC device 110 may transmit packets to PLC data
concentrator 114 using a second set of uplink subbands, and it may
receive packets from PLC data concentrator 114 using a second set
of downlink subbands. In some cases, the first set of uplink
subbands may be at least partially non-overlapping and/or entirely
distinct from the second set of uplink subbands. Similarly, the
first set of downlink subbands may be at least partially
non-overlapping and/or entirely distinct from the second set of
downlink subbands. Moreover, in some implementations, PLC data
concentrator 114 and/or PLC devices 105, 110 may be configured to
process uplink and/or downlink signals from only one subband at a
time ("narrowband"). In other implementations, PLC data
concentrator 114 and/or PLC devices 105, 110 may be configured to
process uplink and/or downlink signals from two or more subbands at
a time ("wideband").
[0019] When operating in wideband mode, a given PLC device may be
capable of transmitting and/or receiving packets spread across two
or more uplink or downlink subbands using a suitable signal
spreading algorithm. It should be noted that, although only three
PLC devices 105, 110 and 114 (data concentrator) are shown in PLC
network 100 in FIG. 1, a typical implementation may include any
number of PLC devices (e.g., dozens of devices) coupled to a same
PLC data concentrator 114. Also, PLC data concentrator 114 may
allocate different uplink subbands to different devices, for
example, based on each individual node's uplink quality.
[0020] Operation of PLC network 100 is now considered based on the
IEEE P1901.2 standard. In this standard, the PHY header portion of
the data frame for the PHY is referred to as a FCH portion. The
first 24 bits [0:23] in the 32 bit TM field of the FCH portion is
used in network communications to communicate the TM information to
the receiver in both the UL and DL for the entire band. The TM
[24:31] field is currently reserved.
[0021] Assume all PLC devices 105, 110 and 114 are configured for
carrier sensing in a first TM (TM 1). The first PLC device 105
sends a data frame for PHY having a FCH portion in TM 1 with its TM
field [0:23] indicating that the data payload will be sent in both
TM 1 and TM 2, or TM 2 alone. The data concentrator 114 may
successfully decode both the FCH and the data payload. The second
PLC device 110 can decode the FCH as it is at TM 1, but cannot
decode the data payload at TM 2 because TM 2 is not good for both
the first and second PLC devices 105, 110. Since the second PLC
device 110 cannot decode the data payload at TM 2, the second PLC
device 110 will consider this scenario a collision and will set its
Virtual Carrier Sensing (VCS) clock to the Extended Inter-Frame
Space (EIFS) value, where the EIFS duration is typically large
(e.g., 252 symbols+an acknowledgement (ACK) duration+response
interframe spacing (RIFS), which being large can degrade network
performance.
[0022] To facilitate inter-device communications among the devices
in PLC networks such as in the PLC network 100 shown in FIG. 1,
including avoiding the above-described collision determination,
each PLC device may implement a data frame for the PHY including a
disclosed PHY header portion which includes information about the
set of tone masks in which the data payload in the data frame will
be transmitted. The PHY header portion is sent to the receiver in a
single TM which provides information about the set (2 or more) of
TMs in which the data payload of the frame will be transmitted,
thus enabling efficient ways of using the set of available
tones.
[0023] Disclosed embodiments can be implemented for the IEEE
P1901.2 standard by enabling the data tone mask (DTM) mode,
generally by setting the DTM field to 1 and using the TM field. For
other standards, one can define additional fields for the TM, which
is another frame design option disclosed herein. As noted above,
each TM mask refers to a discrete frequency band (or subband). When
operating in the DTM mode, the TM bits corresponding to this TM are
relevant for allocating power within that particular tone mask. If
there are multiple TMs used for the data payload, the relevant bits
in the TM for each of the tone masks utilized are used.
[0024] FIG. 2A is a diagram of an example PHY data frame 200 based
on the IEEE 1901.2 standard including a new PHY header portion
shown as FCH portion 220 that utilizes a single TM which includes a
field shown as bit map 227d that provides information about the set
of TMs in which the data payload 240 of the PHY data frame 200
which will be transmitted, suitable for PLC communications,
according to an example embodiment. PHY data frame 200 is shown
including a preamble portion 210, a FCH portion 220, a MAC header
portion 230, a data payload portion 240, and a FCS portion 250.
[0025] The fields of FCH portion 220 are shown to reveal its
structure. FCH portion 220 includes Phase Detection Counter (PDC)
221, Modulation type (MOD) 222; Coherent mode (CM) bits 223, DTM
224, delimiter type (DT) 225, frame length (FL; the PHY frame
length in PHY symbols) 226, tone map (TM) 227 comprising TM [0:7]
227a, TM [8:15] 227b, TM [16:23] 227c, and TM [24:31] 227d, Frame
Control Check Sequence (FCCS) 228, cony zeros (e.g., 6 zeros for
convolutional encoder) 229, and Rsry bits 233.
[0026] In FCH portion 220, TM bits 24:31 227d which are currently
reserved in the IEEE P1901.2 standard, are used to represent the
set of TMs used for the data payload portion 240 as a bit map. A
bitmap in this embodiment refers to a sequence of bits, where each
bit represents whether each of the available TMs is used, or not
used, for the data payload portion 240 in PHY data frame 200.
[0027] FIG. 2B is a diagram of an example FCH portion 220a,
according to an example embodiment. In FCH 220a, the TM [1:23]
represents the TM. The DTM field 224 is set to 0 to indicate TMs,
or set to 1 to indicate the DTM mode. In this embodiment TM bits
24:31 are used for a TM bitmap (as described above for FCH 220)
only when the DTM 224 is set to 1; otherwise they are not
used/reserved. This embodiment can be used with the embodiment
described relative to FIG. 2A above, or can be practiced
separately.
[0028] FIG. 2C is a diagram of an example FCH portion 220b,
according to an example embodiment. In FCH 220b, an additional
field shown as 236 is added to the FCH portion 220b, shown by
example at the end of the FCH portion 220b. This embodiment can
expand the FCH structure to include an additional TM field which
can utilize a bit map representation to represent the TMs used by
the data payload portion 240 of the frame, or can represent the TMs
used by the data payload portion 240 of the frame in a format other
than a bitmap. For example, the format of the identifier in field
236 can comprise <TM#1>, <extension#1>, <TM#2>,
<extension#2>, etc. . . . TM 24:31 may be left as reserved as
in the IEEE P1901.2 standard. In this embodiment, the added field
236 can end as soon as an extension bit is set to 0.
[0029] Advantages of disclosed embodiments include since the PHY
header portion carries the TM information of the data payload
portion of the frame, the data payload portion may be sent in a
different TM or TMs when compared to the TM for the PHY header
portion. This enables nodes in the PLC network to perform carrier
sensing on one TM to send data over multiple TMs that may or may
not include the TM in which carrier sensing is performed by the
node. Disclosed embodiments also solve the Media Access Control
(MAC) Carrier Sense Multiple Access (CSMA) problem that may result
due to this technique since as described above, if the receiver
cannot decode the frame, it will wait for a EIFS duration.
[0030] FIG. 3 is a block diagram schematic of a communication
device 300 having a disclosed modem 304 that implements operation
at a node on a PLC communication channel of a PLC network,
including use of a data frame for PHY including a disclosed PHY
header portion that utilizes a single TM which provides information
about the set of TMs in which the data payload will be transmitted,
according to an example embodiment. Communications device 300
compromises a modem 304 including a processor (e.g., a digital
signal processor, (DSP)) 304a communicably coupled to an associated
memory 305 that that stores a disclosed frame compiling algorithm
for compiling a data frame for the PHY including tone mask
identification information identifying a set of tones used for a
data payload portion of the data frame. Communications device 300
can be used at a service node (which includes switch nodes and
terminal nodes) or a base (data concentrator) node in the PLC
communications network.
[0031] Memory 305 comprises non-transitory machine readable
storage, for example, static random-access memory (SRAM). The
processor 304a is programmed to implement the frame compiling
algorithm. Modem 304 includes a timer 307, such as for ACK
transmission, Carrier Sense Multiple Access/collision avoidance
(CSMA)/CA) back-off and Data transmission purposes.
[0032] Transceiver (TX/RX) 306 is communicably coupled the modem
which allows coupling of the communications device 300 to the
shared powerline 340. The modem 304 is shown formed on an
integrated circuit (IC) 320 comprising a substrate 325 having a
semiconductor surface 326, such as a silicon surface. Memory 305
may be included on the IC 320. In one embodiment the modem 304 is
implemented using 2 processor chips, such as 2 DSP chips. Besides
the DSP noted above, the processor 304a can comprise a desktop
computer, laptop computer, cellular phone, smart phone, or an
application specific integrated circuit (ASIC).
[0033] Disclosed modems 304 and disclosed communications devices
300 can be used in a PLC network to provide a networked device that
in service is connected to a powerline via a power cord. In
general, the "networked device" can be any equipment that is
capable of transmitting and/or receiving information over a
powerline. Examples of different types of networked devices
include, but are not limited or restricted to a computer, a router,
an access point (AP), a wireless meter, a networked appliance, an
adapter, or any device supporting connectivity to a wired or
wireless network.
[0034] FIG. 4 is a flowchart for an example method 400 for PLC
communications in a PLC network that includes using a data frame
for PHY having a PHY header portion that utilizes a single TM which
provides information about the set of TMs in which the data payload
portion of the data frame will be transmitted, according to an
example embodiment. Step 401 comprises compiling the data frame by
a first communications device at a first communications node on a
powerline of a PLC network. The PHY data frame includes a single
tone PHY header portion and a data payload portion in a set of
tones including at least one tone having a frequency different from
a frequency of the single tone. The PHY header portion includes
tone mask identification information identifying the set of tones
in the data payload of the frame.
[0035] The selection of which particular tone mask(s) are used for
the PHY header portion 220, data payload portion 240, and preamble
portion 210 of the data frame is not part of disclosed embodiments.
However, tone mask selection can be handled as known in the art,
for example, by using the tone mask selection described in the IEEE
P1901.2 standard. Step 402 comprises the first communications
device transmitting the data frame over the powerline to a second
communications device at a second communications node on the
powerline. Step 403 comprises the second communications device
receiving the data frame. In step 404, the second communications
device decodes the data payload using the tone mask identification
information received from the PHY header portion, such as based on
one of the embodiments described above regarding FIG. 2A, 2B, or
2C.
[0036] Disclosed embodiments can be applied to PLC standards that
support multi-tone mask modes, such as IEEE P1901.2 standard
compliant PLC networks. Disclosed embodiments will also become
applicable to standards such as G3 and PRIME if such standards
choose to adopt multi-tone mask modes.
[0037] Many modifications and other embodiments of the invention
will come to mind to one skilled in the art to which this invention
pertains having the benefit of the teachings presented in the
foregoing descriptions, and the associated drawings. Therefore, it
is to be understood that the invention is not to be limited to the
specific embodiments disclosed. Although specific terms are
employed herein, they are used in a generic and descriptive sense
only and not for purposes of limitation.
* * * * *