U.S. patent application number 16/679643 was filed with the patent office on 2021-01-14 for physical medium dependent layer bonding.
The applicant listed for this patent is Lantiq Beteilligungs-GmbH & Co. KG. Invention is credited to Vladimir Oksman, Dietmar Schoppmeier.
Application Number | 20210014344 16/679643 |
Document ID | / |
Family ID | 1000005107581 |
Filed Date | 2021-01-14 |
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United States Patent
Application |
20210014344 |
Kind Code |
A1 |
Oksman; Vladimir ; et
al. |
January 14, 2021 |
PHYSICAL MEDIUM DEPENDENT LAYER BONDING
Abstract
A first protocol stack for communication on a first physical
line is implemented. At least parts of a second protocol stack for
communication on a second physical line are implemented. The first
protocol stack and the second protocol stack are bonded at the
Physical Medium Dependent layer of the first protocol stack and the
Physical Medium Dependent layer of the second protocol stack (172).
In some scenarios, the bonding may be at an upper edge of the
Physical Medium Dependent layer, i.e., at the .delta.
interface.
Inventors: |
Oksman; Vladimir;
(Morganville, NJ) ; Schoppmeier; Dietmar;
(Unterhaching, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Lantiq Beteilligungs-GmbH & Co. KG |
Neubiberg |
|
DE |
|
|
Family ID: |
1000005107581 |
Appl. No.: |
16/679643 |
Filed: |
November 11, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15522809 |
Apr 28, 2017 |
10476995 |
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PCT/EP2015/076970 |
Nov 18, 2015 |
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16679643 |
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62081637 |
Nov 19, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 69/14 20130101;
H04L 12/12 20130101; H04L 69/323 20130101; Y02D 30/50 20200801;
H04L 69/18 20130101; H04J 3/0658 20130101 |
International
Class: |
H04L 29/08 20060101
H04L029/08; H04L 29/06 20060101 H04L029/06; H04J 3/06 20060101
H04J003/06; H04L 12/12 20060101 H04L012/12 |
Claims
1-26. (canceled)
27. A method of bonding physical lines at a modem, the method
comprising: implementing a first protocol stack for communication
on a first physical line, implementing at least parts of a second
protocol stack for communication on a second physical line, bonding
the first protocol stack and the second protocol stack at the
Physical Medium Dependent layer of the first protocol stack and at
the Physical Medium Dependent layer of the second protocol
stack.
28. The method of claim 27, wherein said bonding is at an upper
edge of the Physical Medium Dependent layer of the first protocol
stack and an upper edge of the Physical Medium Dependent layer of
the second protocol stack.
29. The method of claim 28, wherein the upper edge of the Physical
Medium Dependent layer is the delta interface.
30. The method of claim 27, wherein said bonding comprises:
receiving messages from an upper layer of the first protocol stack
above the Physical Medium Dependent layer, the messages comprising
at least one of a payload section, a management section, and a
combined payload and management section, distributing the messages
between the first protocol stack and the second protocol stack.
31. The method of claim 30, wherein said distributing comprises
splitting at least some of the messages to distribute fractions of
the messages between the first protocol stack and the second
protocol stack.
32. The method of claim 30, wherein at least those fractions of the
messages comprising the management section and/or the combined
payload and management section are distributed to the first
protocol stack, the management section and the combined payload and
management section indicating management information for the first
protocol stack and the second protocol stack.
33. The method of claim 30, wherein said distributing depends on at
least one of control indices of sections of the messages associated
with the first protocol stack or the second protocol stack, tone
indices of bits of the messages, the tone indices associating the
bits with tones of multitone symbols transmitted on either the
first physical line or the second physical line, and a position of
fractions of the messages within each message.
34. The method of claim 30, wherein said distributing depends on a
predefined rule.
35. The method of claim 27, wherein the first protocol stack
comprises the Physical Medium Dependent layer and at least one
upper layer above the Physical Medium Dependent layer, wherein the
second protocol stack comprises the Physical Medium Dependent layer
and does not comprise the at least one upper layer above the
Physical Medium Dependent layer.
36. The method of claim 27, wherein the first protocol stack is
operated as master, wherein the second protocol stack is operated
as slave.
37. The method of claim 27, further comprising: initializing the
second protocol stack from a powered down state into Showtime,
wherein said bonding is executed in response to initializing the
second protocol stack into Showtime.
38. The method of claim 37, wherein the second protocol stack is
initialized into a Showtime low power state.
39. The method of claim 27, wherein in a first mode said bonding is
not executed, wherein in a second mode said bonding is executed,
wherein the method further comprises: switching between the first
mode and the second mode during Showtime.
40. The method of claim 39, further comprising: in the first mode:
the second protocol stack generating at least one of idle bits and
synchronization symbols for communication on the second physical
line.
41. The method of claim 39, further comprising: in the first mode:
operating the second protocol stack in a Showtime low power state
or in a powered down state.
42. The method of claim 39, further comprising: switching between
the first mode and the second mode depending on at least one of a
traffic load and a traffic throughput of the communication on the
first physical line.
43. The method claim 39, further comprising: switching between the
first mode and the second mode at a point in time between two
time-division multiplex frames of the Physical Medium Dependent
layer and/or at a point in time corresponding to a synchronization
frame of the Physical Medium Dependent layer, the synchronization
frame corresponding to at least one synchronization symbol.
44. The method claim 39, further comprising: in response to
switching between the first mode and the second mode: communicating
control data at least one of the first physical line and the second
physical line, the control data indicating a parameter of said
bonding.
45. The method of claim 27, further comprising: modulating a
sequence of bits output by the Physical Medium Dependent layer of
the first protocol stack into a multitone symbol transmitted on the
first physical line, modulating a sequence of bits output by the
Physical Medium Dependent layer of the second protocol stack into a
multitone symbol transmitted on the second physical line.
46. A device, comprising: a first interface configured to
communicate on a first physical line, a second interface configured
to communicate on a second physical line, at least one processor
configured to implement a first protocol stack for communication on
the first physical line via the first interface, wherein the at
least one processor is further configured to implement at least
parts of a second protocol stack for communication on the second
physical line via the second interface, wherein the at least one
processor is configured to bond the first protocol stack and the
second protocol stack at the Physical Medium Dependent layer of the
first protocol stack and at the Physical Medium Dependent layer of
the second protocol stack.
Description
TECHNICAL FIELD
[0001] Various embodiments relate to a method of bonding physical
lines at a modem and to a corresponding device. In particular,
various embodiments relate to techniques of bonding a first
protocol stack and a second protocol stack at the Physical Medium
Dependent layer.
BACKGROUND
[0002] According to International Telecommunications Union (ITU)
Telecommunications standard (ITU-T) G.998.2 (2005) bonding of a
plurality of physical lines is located in between the physical
layer (layer 1) and the data link layer (layer 2) at the .gamma.
interface.
[0003] Bonding above the physical layer or at an upper edge of the
physical layer has certain restrictions and drawbacks. E.g., it can
be required to provide differential delay compensation buffers to
cope with the required differential delay of up to 10 milliseconds
for high bit rates. In particular, big differential delay
compensation buffers may be required in a scenario where 10 ms
impulse noise impacts one of the bonded physical lines, but not
other bonded physical lines.
[0004] A further drawback is that adding another physical line to a
bonding group can be comparably slow. Thus, switching between
bonded mode and unbonded mode may not be possible or only possible
to a limited degree during Showtime.
[0005] Further limitations and drawbacks relate to operation of the
various physical lines in different modes. E.g., within existing
reference implementations of bonding, operation may be limited to
either full power transmission for all bonded physical lines or low
power mode for all bonded physical lines. A combination of full
power mode for one more bonded physical lines on the one hand side,
with low power mode for further bonded physical lines on the other
hand side may not be possible or only possible to a limited
degree.
[0006] A further drawback of existing reference implementations of
bonding relates to additional bonding overhead introduced. The
bonding overhead reduces the throughput of applications implemented
on the physical lines of a bonded group. E.g., fragmentation using
sequence numbers identifying fragments may be used for distributing
data between bonded physical lines; sequence numbers may require
additional overhead.
SUMMARY
[0007] Therefore, a need exists for advanced techniques of bonding.
In particular, a need exists for techniques which overcome or
mitigate at least some of the above-identified drawbacks and
restrictions.
[0008] This need is met by the features of the independent claims.
The dependent claims define embodiments.
[0009] According to various embodiments, a method of bonding
physical lines at a modem is provided. The method comprises
implementing a first protocol stack for communication on a first
physical line and implementing at least parts of a second protocol
stack for communication on a second physical line. The method
further comprises bonding the first protocol stack and the second
protocol stack at the Physical Medium Dependent layer of the first
protocol stack and at the Physical Medium Dependent layer of the
second protocol stack.
[0010] According to various embodiments, a device is provided. The
device comprises a first interface configured to communicate on a
first physical line. The device further comprises a second
interface configured to communicate on a second physical line. The
device further comprises at least one processor configured to
implement a first protocol stack for communication on the first
physical line via the interface. The at least one processor is
further configured to implement at least parts of a second protocol
stack for communication on the second physical line via the second
interface. The at least one processor is configured to bond the
first protocol stack and the second protocol stack at the Physical
Medium Dependent layer of the first protocol stack and at the
Physical Medium Dependent layer of the second protocol stack.
[0011] According to various embodiments, a computer program product
is provided. The computer program product comprises program code
that can be executed by at least one processor. Executing the
program code by the at least one processor causes the at least one
processor to execute a method. The method comprises implementing a
first protocol stack for communication on a first physical line and
implementing at least parts of a second protocol stack for
communication on a second physical line. The method further
comprises bonding the first protocol stack and the second protocol
stack at the Physical Medium Dependent layer of the first protocol
stack and at the Physical Medium Dependent layer of the second
protocol stack.
[0012] It is to be understood that the features mentioned above and
those yet to be explained below may be used not only in the
respective combinations indicated, but also in other combinations
or in isolation without departing from the scope of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] In the following, various embodiments are explained in
further detail with respect to the accompanying drawings.
[0014] FIG. 1 is a schematic illustration of two modems connected
via a first physical line and a second physical line.
[0015] FIG. 2 is a schematic illustration of a physical layer and a
data link layer of a protocol stack for communication on one of the
physical lines according to FIG. 1, wherein the physical layer
implements a Physical Medium Dependent layer according to various
embodiments.
[0016] FIG. 3 schematically illustrates at greater detail the
physical layer of first and second protocol stacks implemented for
communication on the first and second physical lines, respectively,
wherein FIG. 3 illustrates a first mode where said bonding of the
first and second protocol stacks is not executed according to
various embodiments.
[0017] FIG. 4 generally corresponds to FIG. 3, wherein FIG. 4
illustrates a second mode where said bonding is executed according
to various embodiments.
[0018] FIG. 5 schematically illustrates messages communicated
between the Physical Medium Dependent layer and an upper layer of
the protocol stack which is above the Physical Medium Dependent
layer according to various embodiments.
[0019] FIG. 6 schematically illustrates the messages of FIG. 5 at
greater detail, wherein the messages comprise a management section
and a combined payload and management section and wherein FIG. 6
further illustrates splitting the messages to distribute fractions
of the messages between the first and second protocol stacks
according to various embodiments.
[0020] FIG. 7 generally corresponds to FIG. 6 and illustrates
further embodiments.
[0021] FIG. 8 generally corresponds to FIG. 6 and illustrates
further embodiments.
[0022] FIG. 9 generally corresponds to FIG. 6 and illustrates
further embodiments.
[0023] FIG. 10 illustrates tone indices of bits of the messages,
the tone indices associating the bits with tones of multitone
symbols transmitted on either the first physical line or the second
physical line according to various embodiments.
[0024] FIG. 11 schematically illustrates distributing of messages
received from the upper layer of the first protocol stack above the
Physical Medium Dependent layer at greater detail according to
various embodiments.
[0025] FIG. 12 generally corresponds to FIG. 11 and illustrates
further embodiments.
[0026] FIG. 13 generally corresponds to FIG. 11 and illustrates
further embodiments.
[0027] FIG. 14 schematically illustrates a device according to
various embodiments.
[0028] FIG. 15 is a flowchart of a method of bonding physical lines
at a modem according to various embodiments.
[0029] FIG. 16 is a flowchart of a method according to various
embodiments.
DETAILED DESCRIPTION OF EMBODIMENTS
[0030] In the following, embodiments will be described in detail
with reference to the accompanying drawings. It is to be understood
that the following description of embodiments is not to be taken in
a limiting sense. The scope of the invention is not intended to be
limited by the embodiments described hereinafter or by the
drawings, which are taken to be illustrative only.
[0031] The drawings are to be regarded as being schematic
representations and elements illustrated in the drawings are not
necessarily shown to scale. Rather, the various elements are
represented such that their function and general purpose become
apparent to a person skilled in the art. Any connection or coupling
between functional blocks, devices, components, or other physical
or functional units shown in the drawings or described herein may
also be implemented by an indirect connection or coupling. A
coupling between components may also be established over a wireless
connection. Functional blocks may be implemented in hardware,
firmware, software, or a combination thereof.
[0032] Hereinafter, various techniques of bonding multiple physical
lines are disclosed. E.g., by bonding the multiple physical lines,
Ethernet transport may be distributed across the multiple physical
lines, thereby facilitating high traffic throughput of
communication between a transmitter modem and a receiver modem.
Sometimes, bonding is also referred to as aggregating multiple
physical lines.
[0033] Techniques disclosed herein may be applied to various kinds
of transmission protocols. A particular focus is put, hereinafter,
on transmission according to the ITU-T G.9701 G.fast protocol for
illustrative purposes only. Respective techniques may be readily
applied to other kinds of communication protocols, including, but
not limited to ITU-T G.992.X (ADSL and ADSL 2+), G.993.1 (VDSL1),
and G.993.2 (VDSL2). Respective techniques may also be applied to
non-DSL communication protocols; examples include the Institute of
Electrical and Electronics Engineers (IEEE) 802.11 Wireless Local
Area Network (WLAN) communication protocol and the Third Generation
Partnership Project (3GPP) Long-Term Evolution (LTE) or Universal
Mobile Telecommunications system (UMTS) protocol. Further examples
include Bluetooth and satellite communication.
[0034] E.g., the various techniques disclosed herein can be
applicable for communication system employed for the Internet of
Things (IoT) where a large number of devices communicates. Here,
high traffic throughput, low energy consumption, and flexibility in
operation modes may be of benefit.
[0035] According to embodiments, bonding of first and second
protocol stacks is implemented at the Physical Medium Dependent
(PMD) layer of the first and second protocol stacks. In some
examples, bonding is done at the .delta. interface which
corresponds to an upper edge of the PMD layer of the first and
second protocol stacks.
[0036] Bonding at the upper edge of the PMD layer has particular
advantages for time-synchronized physical lines as are typically
present for G.fast. In such a scenario, symbol boundaries--e.g.,
discrete multitone (DMT) symbol boundaries--in different physical
lines are aligned in time domain and, furthermore, time positions
of synchronization symbols in different physical lines are also
aligned. Such a time-domain synchronization is particularly present
in vectored communication protocols such as ITU-T G.9701,
G.993.2/G.998.4, as well as G.993.5.
[0037] A respective scenario is illustrated schematically by FIG.
1. FIG. 1 illustrates a transmitter 101 and a receiver 111. The
transmitter 101 implements a first interface 105 configured to
communicate via a first physical line 121. The transmitter 101
further implements a second interface 106 configured to communicate
via the second physical line 122. The receiver 111 implements a
first interface 115 configured to communicate via the first
physical line 121. The receiver 111 further implements a second
interface 116 configured to communicate via the second physical
line 122.
[0038] While, with respect to FIG. 1, a scenario is illustrated
where the communication on the first and second physical lines 121,
122 is implemented as uni-directional communication, in other
scenarios bi-directional communication may be readily employed.
E.g., in some scenarios, bi-directional communication in, both,
upstream (US) and downstream (DS) may be implemented in frequency
division duplexing (FDD) and/or time division duplexing (TDD)
modes.
[0039] It is possible that the first physical line 121 is a first
copper wire pair and that the second physical line is a second
copper wire pair. E.g., the first and second physical lines 121,
122 may be integrated into a single cable having a so-called
quad-structure. Typically, for a cable having the quad-structure, a
comparably strong crosstalk between the pairs of wires implementing
the first and second physical lines 121, 122 may be present; at the
same time, a strongly reduced crosstalk may be present between
different cables having quad-structure. A shielding effect to the
outside of the cable may be achieved. Employing both wire pairs of
a cable for a single subscriber in a coordinated fashion can
substantially improve the traffic throughput of the overall
communication system; here, bonding may facilitate such a
coordinated combination of communication.
[0040] Turning to FIG. 2, details of the protocol stacks
implemented for a communication on the first and second physical
lines 121, 122 are illustrated. FIG. 2 schematically illustrates a
protocol stack that may be used in order to operate according to
the G.fast protocol. In other examples, other protocols may be
employed. The protocol stack 170 of FIG. 2 comprises a data link
layer 190 and the physical layer 180. The protocol stack 170 may
comprise further upper layers above the data link layer 190 (not
shown in FIG. 2 for simplicity). In particular, the protocol stack
170 may be structured according to the Open Systems Interconnection
model (OSI model). E.g., the protocol stack 170 may further
comprise (in ascending order) a network layer, a transport layer, a
session layer, a presentation layer, and an application layer (all
not shown in FIG. 2).
[0041] The data link layer 190 may implement various
functionalities such as: protection of communication of data, e.g.,
by means of an Automatic Repeat Request (ARQ) protocol; conversion
between service data units and protocol data units of, e.g.,
Ethernet or TCP/IP; multiplexing of multiple protocols atop the
data link layer; etc. It is possible that the data link layer 190
comprises one or more (sub-)layers such as the logical link control
sublayer and the media access control sublayer (not shown in FIG.
2).
[0042] FIG. 2 further illustrates details of aspects of the
physical layer 180. The physical layer 180 comprises three
(sub-)layers 181-183. The lowest layer is the PMD layer 183. The
PMD layer controls communication of individual bits on the physical
lines 121, 122. E.g., the PMD layer 183 may access an analog front
end (AFE) and generate transmission frames comprising a plurality
of symbols by requesting corresponding data from the upper layers
181, 182. As such, it is possible that the sequence of bits 224
output by the PMD layer 183 is modulated into a multitone symbol
transmitted on one of the physical lines 121, 122. Further
functionality implemented by the PMD layer 183 may comprise
elements selected from the group comprising: modulation; signal
coding; bit synchronization; Forward Error Correction (FEC); bit
interleaving or other channel coding; control of a bit rate,
thereby influencing a traffic throughput; etc. It should be
understood that in specific technical fields the lowest layer of
the protocol stack 170 may be labelled differently than PMD.
[0043] The PMD layer 183 is delimited by the delta (.delta.)
interface 187 from the Physical Medium-specific Transmission
Convergence layer (PMS-TC) 182. The .delta. interface 187, thus, is
the upper edge of the PMD. E.g., the PMS-TC layer 182 may implement
encapsulation functionality.
[0044] The PMS-TC layer 182 is delimited by the .alpha. interface
186 from the Transport Protocol-specific Transmission Convergence
(TPS-TC) layer 181 interfacing to the datalink layer 190 via the
.gamma. interface 185. E.g., the TPS-TC layer 181 may provide
functionality selected from the group comprising: cell conversion;
header error check (HEC) calculation; removing idle cell;
descrambling of payload.
[0045] FIG. 3 illustrates aspects of a first mode 151 where bonding
between a first protocol stack 171 and a second protocol stack 172
is not executed. FIG. 3 is an example where the first and second
protocol stacks 171, 172 operate according to the G.fast
protocol.
[0046] In some examples, data may be communicated on the first
physical line 121 by means of the first protocol stack 171
independently of data communicated on the second physical line 122
by means of the second protocol stack 172. In particular, in such a
scenario it is possible that the second protocol stack 172 is
operated at Showtime in a first mode 151, i.e., fully powered-up
and communicating data on the physical line 122. Such techniques
may increase a traffic throughput.
[0047] In other examples, it is also possible that the second
protocol stack 172 is operated in a Showtime low power state or in
a powered down state. I.e., the Showtime low power state may
correspond to a scenario where initialization of the second
protocol stack 172 from the powered down state has occurred,
but--beyond some management data or control data--payload data is
not communicated via the second physical line 122. E.g., the second
protocol stack 172 may generate idle bits and/or synchronization
symbols for communication on the second physical line 122 in the
first mode 151. Such techniques may reduce power consumption.
[0048] As illustrated with respect to FIG. 4, it is now possible to
switch or transition from the first mode 151--where bonding 301 is
not executed--to a second mode 152 where bonding 301 is executed.
Switching may occur during training and/or during Showtime.
[0049] As can be seen from FIG. 2, the bonding 301 is at the upper
edge 187A, 187B of the PMD layer 183. Bonding 301 can be
implemented using time-synchronous operation--i.e., boundaries of
symbols communicated via the first and second physical lines 121,
122 being in time domain--such that whenever a message is
communicated over the upper edge of the PMD layer 183 of the first
protocol stack 171 (labeled in FIG. 4 as .delta.2 interface 187B) a
corresponding message 223B is communicated over the upper
edge/.delta.2 interface 187B of the PMD layer 183 of the second
protocol stack 172. To achieve this, the bonding 301--implemented
at the upper edge of the PMD layer 183--comprises distributing
messages 223 received from the layer 182 between the first protocol
stack 171 and the second protocol stack 172. In FIG. 4, said
distributing is implemented by a functional/logical entity labelled
.delta. aggregation function (DAF). FIG. 4 illustrates that the
original .delta. interface 187 has been split into the .delta.1
interface 187A and the .delta.2 interface 187B due to the insertion
of the DAF.
[0050] Implementing techniques of bonding 301 at the PMD layer 183,
e.g., as illustrated with respect to FIG. 4 has certain effects.
First, by implementing said bonding 301 at the low PMD layer 183,
it is possible to enable/disable said bonding 301 on-the-fly during
Showtime. E.g., in some examples it is then possible to switch
between the first mode 151 and the second mode 152 depending on a
traffic load and a traffic throughput of communication on the first
physical line 121 via the PMD layer 183 of the first protocol stack
171. E.g., if the traffic load exceeds a certain predefined
threshold, the second mode 152 may be selectively enabled. The
predefined threshold may be dependent on the traffic troughput of
the PMD layer 183 of the first protocol stack 171.
[0051] Further, additional memory--as may be required in reference
implementation where bonding is executed at an upper layer 181,
182, 190--may not be required or only be required to a limited
degree.
[0052] Further, by implementing the bonding 301 according to
techniques disclosed herein, traffic throughput/bit rate
capabilities can be increased. E.g., it can be possible to
implement a traffic throughput of 1 Gbit per second over comparably
long physical lines 121, 122 when implementing a G.fast protocol.
E.g., such traffic throughput may be achieved for a length of the
physical lines 121, 122 of up to 250 meters. In particular, by said
bonding 301, it can be possible to double the available traffic
throughput over a given length of the physical lines 121, 122.
[0053] If compared to reference implementation, a complexity can be
reduced, e.g., due to a reduced size of required memory
buffers.
[0054] Further, in a scenario where quad-structure cables com are
relied upon, a particular improvement of efficiency can be achieved
by bonding 301 the two wire pairs implementing the physical lines
121, 122 due to coordinated communication via both wire pairs.
[0055] Now referring again to FIGS. 3 and 4, details of operation
will be explained. As mentioned above, there are two physical lines
121, 122 associated with a transmitter and receiver 101, 111. Both
the transmitter 101 and the receiver 111 implement PMD layers 183,
each PMD layer 183 associated with the two protocol stacks 171,
172. The TPS-TC, PMS-TC layers 181, 182 of the first protocol stack
171 are permanently--i.e., independently of the first or second
mode of operation 151, 152--connected with the PMD layer 183 of the
first protocol stack 171. The TPS-TC layer 181 is connected to a
user traffic/payload data at the .gamma. interface 185. The payload
data may originate from higher layers above the physical layer 180.
Because of this, the first protocol stack 171 is operating as
so-called master or bonding master. Differently, the second
protocol stack 172 operates as slave or bonding slave. In
particular, the master protocol stack 171 controls operation of the
PMD layers 183 of, both, the first and second protocol stacks 171,
172. In particular, the messages 223 crossing the lower edge of the
layer 182/the .delta.1 interface 187A are distributed between the
PMD layers 183 of the first and second protocol stacks 171, 172. In
particular, the second protocol stack 172 only implements the PMD
layer 183 in the second mode 152; the TPS-TC, PMS-TC layers 181,
182 are not required and used (and, therefore, not shown in FIG.
4).
[0056] FIG. 3 illustrates a situation during unbonded first mode
151. Here, the first protocol stack 171 communicates payload data.
This comprises transmitting payload data across the .gamma.
interface 185 to PMD 183 of the first protocol stack 171 and
receiving payload data from the physical line 121, processing it at
the PMD layer 183 as well as at the TPS-TC, PMS-TC layers 181, 182
and passing the payload data across the .gamma. interface towards
the data link layer 190 in reverse direction. In the unbonded first
mode 151, it is not required that the second protocol stack
172--acting as slave--transmits or receives any payload data;
therefore, the second protocol stack 172 doesn't have to be powered
in full. The second protocol stack 172 may even be powered
down.
[0057] Using the unbonded first mode is possible as long as the
traffic throughput of the first protocol stack 171 is sufficient
for the application speed/the traffic load. Where the traffic
throughput becomes insufficient, a part of the traffic is
distributed to the second protocol stack 172, in the second mode
152 (cf. FIG. 4). For that, the second protocol stack has to
achieve full operation bit rate within a reasonable timeframe of,
e.g., 1-2 seconds. E.g., for this, it can become possible to
transition the second protocol stack 172 from a powered down state
or a Showtime low power state to Showtime. Then, the bonding 301
can be executed in response to initializing the second protocol
stack 172 into Showtime, e.g., from powered down mode or Showtime
low power mode.
[0058] Now referring to FIG. 5, aspects regarding the data exchange
across the .delta. interface 187, 187A, 187B are illustrated. In
particular, FIG. 5 illustrates distributing messages 223 between
the first and second protocol stacks 171, 172.
[0059] Typically, the data exchange at the .delta. interface 187,
187A, 187B is done via so-called "data frames" according to
reference implementation. FIG. 5 illustrates a data frame message
223 being an ordered set of bits or bytes that can be modulated to,
e.g., exactly a single DMT symbol for communication on a physical
line 121, 122. A data frame message 223 can be seen as a row vector
with one entry for each bit. Thus, according to reference
implementations, for every transmit DMT symbol--except
synchronization symbols--the respective PMD layer 183 requests a
data frame message 223 which is delivered by the PMS-TC layer 182;
likewise, for every receive DMT symbol--except synchronization
symbols--the PMD layer 183 delivers a data frame message 223 to the
PMS-TC layer 182.
[0060] During operation, the data frame messages 223 of the first
protocol stack 171 carry payload data and/or management data,
whereas the data frame messages 223 of the second protocol stack
172, in the unbonded first mode 151, do not carry payload data or
management data, but are filled up with idle bits or dummy
bits.
[0061] Illustrated in FIG. 5, upper part is a situation where the
data frame message 223 comprises four bits. When operating in the
unbonded first mode 151, the data frame message 223 communicated
across the lower edge of the PMS-TC layer 182/the .delta.1
interface 187A is the same as the data frame message 223
communicated across the upper edge of the PMD layer 183/the
.delta.2 interface 187B. Thus, in the unbonded first mode 151, the
transmit data frame message 223 generated by the PMS-TC layer 182
of the first protocol stack 171 is identical to the transmit data
frame message passed to the PMD layer 183 of the first protocol
stack 171.
[0062] Next, the situation of the bonded second mode 152. In the
bonded second mode 152 the second protocol stack 172 is powered and
the DAF bonds the PMD layer 183 of the first protocol stack 171 and
the PMD layer 183 of the second protocol stack 172, e.g., as slave
to the master first protocol stack 171. The transmit data frame
messages 223 of the PMS-TC layer 182 of the first protocol stack
171 are distributed between the first protocol stack 171 and the
second protocol stack 172, in particular between the PMD layer 183
of the first protocol stack 171 and the PMD layer of the second
protocol stack 172. Likewise, data frame messages 223 comprising
data received via one of the physical lines 121, 122 are bonded,
e.g., by the DAF, and passed to the layer 182 of the first protocol
stack 171.
[0063] In the bonded second mode 152, in some examples, any
transmit data frame message 223 generated by the PMS-TC layer 182
of the first protocol stack 171 is distributed either to the PMD
layer 183 of the first protocol stack 171 or to the PMD layer 183
of the second protocol stack 172.
[0064] In particular in such an example, it is possible to flexibly
adapt the amount of data distributed to the first protocol stack
171 in comparison to the amount of data distributed to the second
protocol stack 172 (bonding strength). This may be implemented by
distributing every second, third, fourth, etc. transmit data frame
message 223 to the second protocol stack 172 for transmission on
the second physical line 122. E.g., the bonding strength may be
adjusted depending on at least one of the traffic load and the
traffic throughput of the communication on the physical line 121.
To facilitate time-synchronized transmission the PMD layer 183 of
the second protocol stack 172 may fill up transmission frames with
idle bits where required.
[0065] In FIG. 5, lower part, a further example is shown. Here, a
data frame message 223 generated by the PMS-TC layer 182 of the
first protocol stack 171 is a concatenation of a first fraction
223A corresponding to the data frame message to be passed to the
PMD layer 183 of the first protocol stack 171--and a second
fraction 223B corresponding to the data frame message to be passed
to the PMD layer 183 of the second protocol stack 172. This
corresponds to a vectored concatenation of to row vectors as
illustrated in the lower part of FIG. 5. In such a scenario, the
distributing comprises splitting at least some of the messages 223
to distribute the fractions 223A, 223B of the messages 223 between
the first protocol stack 171 and the second protocol stack 172. In
particular, in such a scenario the distributing may depend on a
position of the fractions 223A, 223B of the messages 223 within
each message 223. E.g., in the example illustrated in the lower
part of FIG. 5, the fraction 223A associated with the PMD layer 183
of the first protocol stack 171 is located in the beginning of the
message 223, i.e., at the most significant bit, while the fraction
223B associated with the PMD layer 183 of the second protocol stack
172 is located at the end of the data frame message 223, i.e., at
the least significant bit. In other examples, the reverse order is
conceivable where the fraction 223A associated with the PMD layer
183 of the first protocol stack 171 is located at the least
significant bit.
[0066] With respect to FIG. 5 above, a specific rule for
distributing the data frame messages 223 between the first and
second protocol stacks 171, 172 has been illustrated. In the
various scenarios disclosed herein, it is possible to implement
various kinds and types of rules of said distributing. E.g., such
rules of distributing the data frame messages 223 can be predefined
or can be negotiated/aligned between the transceivers 101, 111
during startup or during Showtime when switching between the first
mode 151 and the second mode 152. E.g., respective control data
indicating such a predefined rule may be communicated on at least
one of the first physical line 121 and the second physical line
122, e.g., in response to switching between the first mode 151 and
the second mode 152.
[0067] Hereinafter, some examples are given of specific rules of
distributing the data frame messages 223 between the first and
second protocol stacks 171, 172.
[0068] In a first example, all data frame messages 223 are
distributed between the first and second protocol stacks 171, 172,
e.g., in alternating order or using a different pattern having a
weaker bonding strength.
[0069] In a second example, all data frames having indices larger
than zero (the indices corresponding to a position of a
transmission frame) are distributed between the first and second
protocol stacks 171, 172, e.g., in alternating order or using a
different pattern. Here, data frames having index zero in the
transmission frame may all be assigned to either the first protocol
stack 171 or the second protocol stack 172. Data frame messages 223
having index zero in the transmission frame are typically
positioned at the beginning of the transmission frame. Typically,
data frame messages 223 having index zero carry a dedicated
management section including management information for the first
protocol stack 171 and/or the second protocol stack 172. Concerning
the distributing between the first and second protocol stacks 171,
172, in case of G.fast it is typically distinguished between the
synchronization symbols which are transporting no data frame
messages 223, data symbols which are transporting data frame
message 223 with index larger than zero and RMC symbols which are
transporting data frame messages 223 with index zero. The various
indices of the data frame messages are also illustrated by FIG. 9-3
of G.9701 (Dec. 5, 2014).
[0070] With regard to the G.fast protocol, examples of management
information comprise the Robust Management Channel (RMC) and the
embedded operations channel (eoc) which is typically carried in a
combined management and payload section. In particular, management
information such as the RMC or the eoc may be determined by one of
the upper layers 181, 182. Management information for the first
protocol stack 171 or the second protocol stack 172 may comprise
elements selected from the group comprising: TDD framing
parameters; Showtime Adaptive Rate (SAR) parameters; and vectoring
error reports.
[0071] Now turning to FIG. 6, various aspects with respect to
distributing of the data frame messages 223 received from the layer
182 between the PMD layer 183 of the first protocol stack 171 and
the PMD layer 183 of the second protocol stack 172 are illustrated.
In the scenario FIG. 6, a data frame message 223 is received which
comprises a first management section 223-1 comprising management
information for the first protocol stack 171 and comprising a
second management section 223-2 comprising management information
for the second protocol stack 172. E.g., the data frame message 223
of FIG. 6 could have index zero, i.e., dedicated for the beginning
of a transmission frame. The data frame message 223 further
comprises a combined payload and management section which carries
payload data and management information for the first protocol
stack 171 and/or the second protocol stack 172. E.g., in the G.fast
framework, the sections 223-1, 223-2 may correspond to the RMC
while the section 223-3 corresponds to the data transfer unit (DTU)
used to transfer payload data bits and further comprising eoc
management information (not illustrated in FIG. 6).
[0072] The data frame message 223 is received from the PMS-TC layer
182 of the first protocol stack 171. I.e., that the management
information for the second protocol stack 172 is also generated and
transported by the layers 181, 182 of the first protocol stack 171
in the bonded second mode 152. In particular, in the G.fast
framework, the eoc management information indicates management
information for, both, the first protocol stack 171 and the second
protocol stack 172. Also, the TMS-TC, PMS-TC layers 181, 182 of the
first protocol stack 171, in the G.fast framework, generate the RMC
management sections indicating, both, management information for
the first protocol stack 171 and the second protocol stack 172,
respectively.
[0073] In the example of FIG. 6, the RMC management sections 223-1,
223-2 are, both, distributed to the first protocol stack 171 only,
i.e., are not distributed to the second protocol stack 172. Here,
the fraction 223A which comprises the management sections 223-1,
223-2 are distributed to the first protocol stack 171.
[0074] FIG. 7 illustrates a further scenario, where the RMC
management sections 223-1, 223-2 are distributed to, both, the
first protocol stack 171 and the second protocol stack 172. Here,
the management section 223-1 (the management section 223-2)
indicating management information for the first protocol stack 171
(the second protocol stack 172) is communication on the first
physical line 121 (the second physical line 122).
[0075] FIG. 8 illustrates a further scenario of distributing the
data frame messages 223 between the first and second protocol
stacks 171, 172. In the scenario of FIG. 8, only a single RMC
management section 223-1 is included in the data frame message 223;
e.g., the single RMC management section 223-1 may indicate
management information for only one of the first or second protocol
stacks 171, 172 or may indicate management information for, both,
the first and second protocol stacks 171, 172.
[0076] The scenario of FIG. 9 illustrates a further scenario where
a data frame message 223 has an index larger than zero, i.e., being
positioned not in front of a transmission frame of the PMD layer
183; such a data frame message 223 does not comprise any RMC
management section 223-1, 223-2; but may include eoc management
information.
[0077] In the various scenarios disclosed above, it may be helpful
to distinguish between the management sections 223-1, 223-2
indicating management information for the first protocol stack 171
on the one hand side, and the management sections 223-1, 223-2
indicating management information for the second protocol stack 172
on the other hand side. For this purpose, it is possible that
management information--such as RMC information or eoc
information--includes special identification bits to enable
differentiation between management information for the first and
second protocol stacks 171, 172, respectively. Such control indices
implemented by the identification bits may facilitate
distinguishing the control sections 223-1, 223-2 at the upper
PMS-TC, TMS-TC layers 181, 182. The control indices may also
facilitate distributing between the first and second protocol
stacks 171, 172.
[0078] In a further example, the management sections 223-1, 223-2
are distinguished by the time position, respectively the position
within each data frame message 223. Such a scenario is conceivable
in a scenario where transmission frames are associated with
dedicated data frame messages 223 or respective sections 223-1,
223-2 of data frame messages 223 as is the case for RMC management
information. Such a scenario is in particular facilitated by
time-synchronized physical lines 121, 122 of a bonding group.
Distinguishing between management information for the first and
second protocol stacks 171, 172 based on the time position of the
received transmission frames may thus be only possible for a
limited degree in the G.fast framework for eoc management
information which is communicated together with the payload data
and has its insertion/extraction allocation at the layer
181--unless a special mapping of eoc management information aligned
with DTU 223-3 boundaries and boundaries of the data frame messages
223 is used.
[0079] In still a further embodiment, tone indices of bits of the
data frame messages 223 are used to distinguish between management
information for the first and second protocol stacks 171, 172,
respectively. E.g., a concept of so-called virtual tone indices may
be employed where the value of the tone indices enables to
distinguish between tones used for communicating on the first
physical line 121 via the first protocol stack 171 and tones used
for communicating on the second physical line 122 via the second
protocol stack 172. Also, the tone indices may facilitate the
distributing between the first and second physical lines 172,
172.
[0080] Such a scenario of tone indices is illustrated in FIG. 10
where the various tones of the multi-tone signals used for
communicating on the physical lines 121, 122 are illustrated in a
constellation diagram. Respective indices may be used to judge
which protocol stack 171, 172 the respective section 223A, 223B of
a data frame message 223 should be distributed to. E.g., the
virtual tone indices of the second protocol stack 172--operating as
bonding slave--can correspond to the tone indices of the first
protocol stack 171--acting as bonding master--increased by the
highest tone index of the first protocol stack 171.
[0081] FIGS. 11-13 illustrate the distributing of data frame
messages 223 between the first and second protocol stacks 171, 171
at greater detail. Here, the PMD layer 183 of the first protocol
stack 171 is labelled "PMDa" and the PMD layer 183 of the second
protocol stack 172 is labelled "PMDb". FIG. 11 shows a scenario
where data frame messages having index zero and data frame messages
223 having indices larger than zero are distributed. The data frame
messages 223 having indices larger than zero contain payload data
bits only, whereas the data frame messages 223 having index zero
contain, both, payload data bits and RMC management bits.
[0082] Two examples are conceivable regarding distributing of the
management section 223-1, 223-2 having RMC management information.
First--as illustrated in FIG. 11--the management sections 223-1,
223-2 indicative of RMC management information for, both, the first
and second protocol stacks 171, 172 are transported via the PMD
layer 183 of the first protocol stack 171, only. Such a scenario
may be difficult to implement where management sections 223-1,
223-2 are present in each data frame message 223, e.g., due to
synchronization purposes, facilitating low-power mode, etc.
[0083] A second example as to implement two logical management
channels, i.e., to distribute the management sections 223-1, 223-2
between, both, the first and second protocol stacks 171, 172 (as
illustrated in FIGS. 12 and 13). Here, the first physical line 121
is used for communicating management sections 223-1, 223-2
indicating management information for the first protocol stack 171;
while the second physical line 122 is used for communicating
management sections 223-1, 223-2 indicating management information
for the second protocol stack 172.
[0084] Now turning to FIG. 14, a device 501 is illustrated which
may implement techniques of bonding at the PMD layer 183 as
disclosed herein. E.g., the device 501 may implement the
transmitter 101 and/or the receiver 111. The device 501 comprises
two AFEs 505, 506 for communicating on the physical lines 121, 122,
respectively. US and DS communication is possible, e.g., in a TDD
mode. The AFEs 505, 506 together with a digital front end (DFE) 502
implement the two interfaces 105, 115, 106, 116 of the transmitter
101 and/or the receiver 111, respectively. The DFE 502 comprises a
processor 512 and a memory 511. The memory 511 can store program
code that can be executed by the processor 512. Executing the
program code causes the processor 512 to perform techniques as
disclosed herein with respect to, e.g., bonding at the PMD layer
183, in particular at the .delta. interface 187, distributing data
frame messages 283 to the first protocol stack 171 and/or the
second protocol stack 172, splitting data frame messages 283,
implementing the first protocol stack 171, implementing the second
protocol stack 172, etc. The device 501 further comprises a human
machine interface (HMI) 515 configured to output information to a
user and configured to receive information from a user. The HMI 515
is optional.
[0085] FIG. 15 is a flowchart illustrating a method that may be
executed by the processor 512. First, at 1001, the first and second
protocol stacks 171, 172 are implemented. Here, in particular, it
is possible that all layers 180, 190 and layers 181-183 are
implemented for the first protocol stack 171, but that only the PMD
layer 183 is implemented for the second protocol stack 172 (cf.
FIG. 4).
[0086] Next, at 1002, the first and second protocol stacks 171, 172
are bonded 301 at the PMD layer 183. In particular, bonding may
occur at the upper edge of the PMD layer 181, i.e., at the .delta.
interface 187, 187A, 187B.
[0087] FIG. 16 is a flowchart of a method according to various
embodiments. First, at 1011, the first protocol stack 171 and the
second protocol stack 172 are initialized. During the start-up
procedure, information may be exchanged between the transmitter 101
and the receiver 111. Respective control data may be communicated
on at least one of the first physical line 121 and the second
physical line 122 and may indicate a parameter of said bonding
301.
[0088] E.g., the control data may indicate, in a first example,
whether a physical line 121, 122 shall be a bonding master
candidate or a bonding slave candidate during Showtime operation.
In a second example, alternatively or additionally, the control
data may indicate the distribution bit order, i.e., whether the
received data frame messages 223 comprise fractions to be
distributed to the first protocol stack 171 at the most significant
bit or at the least significant bit (as illustrated above with
respect to FIG. 5). In a third example, alternatively or
additionally, the control data may indicate the size--e.g., in
bits--and distribution order of data frame messages 223 into the
first and second protocol stacks 171, 172.
[0089] During start-up/training at 1011, it is possible to
synchronize the communication on the first physical line 121 and
the communication on the second physical line 122 in time domain.
In particular, generation of transmission frames by the physical
media dependent layers 183 of the first and second protocol stacks
171, 172 may be synchronized in time domain.
[0090] FIG. 16 illustrates a scenario where initially only the
first protocol stack 171 is operated at Showtime, 1012.
Differently, the second protocol stack 172 goes to a Showtime low
power state after initialization from powered down state, 1013.
I.e., initially, payload data is communicated on the first physical
line 121 via the PMD layer 171 of the first protocol stack 171,
only. The second protocol stack 172 is initialized into Showtime
only later.
[0091] Next, at 1014, it is checked whether the traffic--which is
currently routed via the first protocol stack 171 only--exceeds a
certain threshold. Only if this is the case, switching from the
first mode 151 to the second mode 152 employing bonding 301 is
executed. Thus, as can be seen from FIG. 16, the power state of the
second protocol stack 171--which is now operated at Showtime, 1015,
to facilitate the bonding 301--is controlled depending on the
traffic throughput demand and the bonding.
[0092] At 1017 it is checked whether the traffic throughput is
still above the threshold. If this is not the case, it is switched
back from the second mode 152 to the first mode 151 and bonding 301
is stopped.
[0093] As can be seen from the exemplary scenario of FIG. 16, it is
possible to switch from unbonded first mode 151 to bonded second
mode 152 (bonding entry); it is also possible to switch back from
bonded second mode 152 to unbonded first mode 151 (bonding exit).
In particular, it is possible to switch back and forth from the
first and second modes 151, 152 during Showtime.
[0094] Switching between the modes 151, 152 can be controlled by
upper layers 190, 181, 182 above the PMD layer 183. In particular,
the switching can depend on the traffic throughput of the
applications delivering payload data. In particular, switching back
and forth between the first and second modes 151, 152 can be
implemented analogous to switching between low-power mode and
full-power mode according to the ITU-T G.9701. Whenever an
application requires a higher traffic throughput than offered by
the PMD layer 183 of the bonding master first protocol stack 171,
the first protocol stack 171 indicates to the higher layers 190,
181, 182 that bonding 301 is required. Then, the higher layers 190,
181, 182 initiate a bonding entry procedure. Whenever the
applications do not require high traffic throughput anymore that is
higher than traffic throughput offered on the first physical line
121, only, the higher layers 190, 181, 182 initiate the bonding
exit procedure and switch back to the first mode 151. A certain
hysteresis of switching between the first and second modes 151, 152
can be considered in time domain to avoid permanent toggling
between the first and second modes 121, 122 for traffic throughput
varying close to the respective threshold.
[0095] Various scenarios are conceivable for aligning the switching
between the first mode 151 in the second mode 152 in time domain.
E.g., for alignment of the switching between the transmitter 101
and the receiver 111, the point in time or time instant of each
particular switching can be coordinated via control data exchanged
between the transmitter 101 and the receiver 111. E.g., in the
G.fast scenario, the eoc or the RMC can be employed. In particular,
exchange of control data can be implemented analogous to reference
implementations of online reconfiguration such as for SRA.
[0096] It is possible that switching between the first mode 151 and
the second mode 152 occurs between two time-division multiplex
frames of the PMD layer 183 and/or at a point in time corresponding
to a synchronization frame of the PMD layer 183. The
synchronization frame may correspond to at least one
synchronization symbol communicated on one of the physical lines
121, 122. Hence, it is possible that the time instant from which
the new bonded or unbonded mode 151, 152 starts is the beginning of
a superframe, a particular logical frame, or a particular TDD
frame. From the start of a new bonded mode 152, the layer 182
starts to dispatch data frame messages 223 in a manner as specified
by a predefined rule of distributing. E.g., the layer 182 can
dispatch data frame messages 223 in a concatenated manner--i.e.,
comprising two individual data frame messages as sections 223A,
223B for distributing to the PMD layer 183 of the first protocol
stack 171 or the second protocol stack 172, respectively (cf. FIG.
5, lower part). Since synchronization symbols do not carry payload
data or other data included in the data frame message 223 and are
communicated on both physical lines 121, 122 at the same point in
time, they can be used to mark a switching point. In particular,
such a technique enables the receiver 111 to detect the switching
and implement changes to the mode of operation of the upper layers
181, 182 and further implementing the DAF. E.g., the first protocol
stack 171 can handle switching procedures between the modes 151,
152 in a manner comparable to reference implementations with
respect to SRA or Fast Rate Adaptation (FRA). For sake of channel
estimation, the PMD layer 183 of the second protocol stack 172
typically sends synchronization symbols in both modes 151, 152.
[0097] With respect to FIG. 16, a scenario has been illustrated
where switching to the second mode 152 comprising bonding 301 is
triggered by a required traffic, 1014, 1017. In other examples, it
is also possible to initialize the second protocol stack 172 from a
powered down state into Showtime and execute bonding 301 in
response to initializing the second protocol stack 172 into
Showtime. I.e., in such a scenario it is possible that the second
mode 152 is activated automatically once the second protocol stack
172 has initialized into Showtime--irrespective of the traffic
throughput. Here, the second protocol stack 172 implementing the
bonding slave is bonded to the first protocol stack 171
implementing the bonding master immediately and autonomously after
going to Showtime, e.g., at the first data frame message 223 of the
first superframe.
[0098] In the various scenarios disclosed herein, examples have
been given where the first protocol stack 171 acts as a master with
respect to the second protocol stack 172 implementing a slave.
Various scenarios are conceivable for deciding which protocol stack
171, 172 acts as master and slave, respectively. In one example,
the protocol stack 171, 172 acting as bonding master is defined by
the PMD layer 183 which is going first to Showtime after power up.
Hence, it is possible that the first protocol stack 171 acting as
master is initialized first into Showtime and that only then the
second protocol stack 172 is initialized into Showtime.
[0099] Summarizing, above various techniques for bonding in the
modem have been illustrated, in particular for a modem having two
pairs of wires, each pair being coupled respectively to a master
and slave module, wherein at least one of the master and slave
module has a TMS-TC layer 181 and the PMS-TC layer 182 coupled to a
PMD layer 183 through a .delta. interface 187, 187A, 187B, wherein
the two pairs of wires are bonded at the PMD layer 183. Here, it is
possible that the master controls the two physical media dependent
layers 183 of the first and second protocol stacks 171, 172,
respectively. Time of bonding entry and bonding strength can be
adjusted by upper layers 181, 182, 190, in particular by a traffic
throughput demand of applications implemented in upper layers 181,
182, 190. The power of the protocol stack of the bonding slave can
be adjusted by the time of the bonding entry and/or the bonding
strength.
[0100] By the various techniques disclosed herein, effects can be
achieved. In particular, dynamic switching between a bonded state
and an unbonded during Showtime is possible. The switching can
occur within a time duration corresponding to a single superframe.
The switching can mimic online reconfiguration according to
reference implementation and therefore enable simple implementation
for the physical layer of transmitter and receiver.
[0101] By the techniques disclosed herein, further, a higher
traffic throughput can be achieved, because bonding at the PMD
layer typically does not require a significant bonding overhead to
be communicated via the physical lines. In particular, it is not
required--as in reference implementation--to segment data as an
upper layer and include respective sequence numbers in the
segmented data in order to facilitate data reassembly. Instead, the
time-synchronized operation of the PMD layers of the first and
second protocol stacks can be relied upon for reassembly.
[0102] A further effect is that power consumption can be
significantly reduced. In particular, where operation in an
unbonded first mode is sufficient in terms of required traffic
throughput, protocol stacks implementing bonding slaves can be put
into a low-power mode. This may be particularly relevant for IoT
applications.
[0103] Further, by implementing techniques of bonding as disclosed
herein, it is typically not required to implement differential link
delay compensation buffers. This and other techniques disclosed
herein reduce the complexity required. In particular, it is not
required to implement segmentation at the data link layer or an
upper edge of the physical layer--rendering it unnecessary to
include respective segmentation sequence numbers. Further, it is
not required to re-order segment and data chunks by means of such
sequence numbers. Further, at startup it is not required to
negotiate a special bonding function.
[0104] Although the invention has been shown and described with
respect to certain preferred embodiments, equivalents and
modifications will occur to others skilled in the art upon the
reading and understanding of the specification. The present
invention includes all such equivalents and modifications and is
limited only by the scope of the appended claims.
[0105] E.g., while various examples have been disclosed with
respect to the G.fast protocol, it is possible to readily apply the
respective techniques to other communication systems or protocols.
In particular, respective techniques as disclosed herein may be
readily applied to multitone communication in time-synchronized
physical lines. E.g., while various scenarios have been disclosed
with respect to wired physical lines, respective techniques may be
readily applied to air interfaces.
[0106] E.g., while above various examples have been discussed with
respect to US, respective techniques may be readily applied to DS.
Further, the techniques disclosed herein are not limited to
uni-directional communication on the physical lines, but can be
applied to bi-directional communication, e.g., in a TDD or FDD
geometry.
[0107] Further, while above reference has been made to various
specific layers of the physical layer such as the TMS-TC layer and
the PMS-TC layer, in other scenarios, other kinds of layers of the
physical layer may be implemented. E.g., different terminology may
be adapted for the layers by standards according to the ITU-T or
the OSI.
* * * * *