U.S. patent application number 16/362293 was filed with the patent office on 2020-09-24 for proactive echo cancellation (ec) training.
This patent application is currently assigned to Cisco Technology, Inc.. The applicant listed for this patent is Cisco Technology, Inc.. Invention is credited to Hang Jin, Tong Liu.
Application Number | 20200304170 16/362293 |
Document ID | / |
Family ID | 1000005074040 |
Filed Date | 2020-09-24 |
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United States Patent
Application |
20200304170 |
Kind Code |
A1 |
Jin; Hang ; et al. |
September 24, 2020 |
PROACTIVE ECHO CANCELLATION (EC) TRAINING
Abstract
Proactive Echo Cancellation (EC) training may be provided.
First, a plurality of Echo Cancellation Training Opportunities
(ECTOs) may be identified in an upstream bandwidth allocation.
Identifying the ECTOs may comprise identifying a corresponding
plurality of mini-slots in a two dimensional time frequency space
designated as not to be used for Upstream (US) traffic. Then Echo
Cancellation Training (ECT) may be conducted for each of the
plurality of ECTOs.
Inventors: |
Jin; Hang; (Plano, TX)
; Liu; Tong; (Acton, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cisco Technology, Inc. |
San Jose |
CA |
US |
|
|
Assignee: |
Cisco Technology, Inc.
San Jose
CA
|
Family ID: |
1000005074040 |
Appl. No.: |
16/362293 |
Filed: |
March 22, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04B 3/238 20130101;
H04L 2012/6421 20130101; H04L 12/2898 20130101; H04L 12/6418
20130101; H04L 2012/6491 20130101 |
International
Class: |
H04B 3/23 20060101
H04B003/23; H04L 12/64 20060101 H04L012/64; H04L 12/28 20060101
H04L012/28 |
Claims
1. A method comprising: identifying a plurality of Echo
Cancellation Training Opportunities (ECTOs) in an upstream
bandwidth allocation map, wherein identifying the ECTOs comprises
identifying a corresponding plurality of mini-slots in a two
dimensional time frequency space designated as not to be used for
Upstream (US) traffic; and conducting Echo Cancellation Training
(ECT) for each of the plurality of ECTOs, wherein conducting ECT
for each of the plurality of ECTOs comprises: determining
iteratively, on a frame-by-frame basis, Echo Cancellation (EC)
coefficients for each subcarrier in each mini-slot of the plurality
of mini-slots, the each mini-slot comprising a fraction of an
upstream bandwidth, and updating an echo canceler with the
determined EC coefficients each time a frame has been
completed.
2. The method of claim 1, wherein each of the plurality of
mini-slots have a different offset relative to a start of a channel
spectrum.
3. The method of claim 1, wherein the plurality of mini-slots are
spread over a plurality of frames.
4. The method of claim 1, wherein identifying the plurality of
mini-slots comprises identifying a Service Flow Identifier (SID)
for each of the plurality of mini-slots corresponding to a NULL
SID.
5. The method of claim 1, wherein identifying the plurality of
mini-slots comprises identifying a Service Flow Identifier (SID)
for each of the plurality of mini-slots comprising a SID
corresponding to a service flow not used for US traffic.
6. (canceled)
7. The method of claim 1, further comprising: updating the echo
canceler with the determined EC coefficients after determining the
EC coefficients for the each subcarrier in the plurality of
mini-slots.
8. The method of claim 1, further comprising receiving the upstream
bandwidth allocation map from a Cable Modem Termination System
(CMTS) that scheduled the plurality of ECTOs in the upstream
bandwidth allocation map.
9.-20. (canceled)
21. The method of claim 1, wherein the ECTOs comprise explicit
ECTOs.
22. The method of claim 1 wherein the ECTOs comprise implicit
ECTOs.
23. A system comprising: a memory storage; and a processing unit
coupled to the memory storage, wherein the processing unit is
operative to: identify a plurality of Echo Cancellation Training
Opportunities (ECTOs) in an upstream bandwidth allocation map,
wherein the processing unit being operative to identify the ECTOs
comprises the processing unit being operative to identify a
corresponding plurality of mini-slots in a two dimensional time
frequency space designated as not to be used for Upstream (US)
traffic; and conduct Echo Cancellation Training (ECT) for each of
the plurality of ECTOs, wherein the processing unit being operative
to conduct ECT for each of the plurality of ECTOs comprises the
processing unit being operative to: determine iteratively, on a
frame-by-frame basis, Echo Cancellation (EC) coefficients for each
subcarrier in each mini-slot of the plurality of mini-slots, the
each mini-slot comprising a fraction of an upstream bandwidth, and
update an echo canceler with the determining EC coefficients each
time a frame has been completed.
24. The system of claim 23, wherein the plurality of mini-slots
each have a different offset relative to a start of a channel
spectrum.
25. The system of claim 23, wherein the plurality of mini-slots are
spread over a plurality of frames.
26. The system of claim 23, wherein the processing unit being
operative to identify the plurality of mini-slots comprises the
processing unit being operative to identify a Service Flow
Identifier (SID) for each of the plurality of mini-slots
corresponding to a NULL SID.
27. The system of claim 23, wherein the processing unit being
operative to identify the plurality of mini-slots comprises the
processing unit being operative to identify a Service Flow
Identifier (SID) for each of the plurality of mini-slots comprising
a SID corresponding to a service flow not used for US traffic.
28. The system of claim 23, wherein the processing unit is further
operative to receive the upstream bandwidth allocation map from a
Cable Modem Termination System (CMTS) that scheduled the plurality
of ECTOs in the upstream bandwidth allocation map.
29. The apparatus of claim 23, wherein the ECTOs comprise explicit
ECTOs.
30. A non-transitory computer readable medium storing instructions
which when executed perform a method comprising: identifying a
plurality of Echo Cancellation Training Opportunities (ECTOs) in an
upstream bandwidth allocation map, wherein identifying the ECTOs
comprises identifying a corresponding plurality of mini-slots in a
two dimensional time frequency space designated as not to be used
for Upstream (US) traffic; and conducting Echo Cancellation
Training (ECT) for each of the plurality of ECTOs, wherein
conducting ECT for each of the plurality of ECTOs comprises:
determining iteratively, on a frame-by-frame basis, Echo
Cancellation (EC) coefficients for each subcarrier in each
mini-slot of the plurality of mini-slot, the each mini-slot
comprising a fraction of an upstream bandwidth, and updating an
echo canceller with the determined EC coefficients each time a
frame has been completed.
31. The non-transitory computer readable medium of claim 30,
wherein the plurality of mini-slots each have a different offset
relative to a start of a channel spectrum.
32. The non-transitory computer readable medium of claim 30,
wherein the plurality of mini-slots are spread over a plurality of
frames.
33. The non-transitory computer readable medium of claim 30,
wherein identifying the plurality of mini-slots comprises
identifying a Service Flow Identifier (SID) for each of the
plurality of mini-slots corresponding to a NULL SID.
34. The non-transitory computer readable medium of claim 30,
wherein identifying the plurality of mini-slots comprises
identifying a Service Flow Identifier (SID) for each of the
plurality of mini-slots comprising a SID corresponding to a service
flow not used for US traffic.
Description
TECHNICAL FIELD
[0001] The present disclosure relates generally to echo
cancellation.
BACKGROUND
[0002] A Hybrid Fiber-Coaxial (HFC) network is a broadband network
that combines optical fiber and coaxial cable. It has been commonly
employed globally by cable television operators. In a HFC cable
network, television channels are sent from a cable system's
distribution facility to local communities through optical fiber
trunk lines. At the local community, a box translates the signal
from a light beam to electrical signal, and sends it over cable
lines for distribution to subscriber residences. The optical fiber
trunk lines provide adequate bandwidth to allow future expansion
and new bandwidth-intensive services.
BRIEF DESCRIPTION OF THE FIGURES
[0003] The accompanying drawings, which are incorporated in and
constitute a part of this disclosure, illustrate various
embodiments of the present disclosure. In the drawings:
[0004] FIG. 1 is a block diagram of a system for providing
proactive Echo Cancellation (EC) training;
[0005] FIG. 2 is a flow chart of a method for providing proactive
EC training;
[0006] FIG. 3 illustrates Explicit Echo Cancellation Training
Opportunity (EECTO) scheduling;
[0007] FIG. 4 illustrates Implicit Echo Cancellation Training
Opportunity (IECTO) scheduling; and
[0008] FIG. 5 is a block diagram of a computing device.
DETAILED DESCRIPTION
Overview
[0009] Proactive Echo Cancellation (EC) training may be provided.
First, a plurality of Echo Cancellation Training Opportunities
(ECTOs) may be identified in an upstream bandwidth allocation.
Identifying the ECTOs may comprise identifying a corresponding
plurality of mini-slots in a two dimensional time frequency space
designated as not to be used for Upstream (US) traffic. Then Echo
Cancellation Training (ECT) may be conducted for each of the
plurality of ECTOs.
[0010] Both the foregoing overview and the following example
embodiments are examples and explanatory only, and should not be
considered to restrict the disclosure's scope, as described and
claimed. Furthermore, features and/or variations may be provided in
addition to those described. For example, embodiments of the
disclosure may be directed to various feature combinations and
sub-combinations described in the example embodiments.
Example Embodiments
[0011] The following detailed description refers to the
accompanying drawings. Wherever possible, the same reference
numbers are used in the drawings and the following description to
refer to the same or similar elements. While embodiments of the
disclosure may be described, modifications, adaptations, and other
implementations are possible. For example, substitutions,
additions, or modifications may be made to the elements illustrated
in the drawings, and the methods described herein may be modified
by substituting, reordering, or adding stages to the disclosed
methods. Accordingly, the following detailed description does not
limit the disclosure. Instead, the proper scope of the disclosure
is defined by the appended claims.
[0012] Multiple-system operators (MSOs) are operators of multiple
cable or direct-broadcast satellite television systems. These
systems may include HFC networks. To amplify upstream (US) signals
and downstream (DS) signals in the HFC network, MSOs may use nodes
deployed within the HFC. In the HFC network, a node may comprise a
container that may house optical and electrical circuitry. An
optical fiber cable or a coaxial cable may be connected to an input
side of the node and a plurality of coaxial cables may be connected
to a output side of the node. The input side of the node may be
connect to a headend in the HFC network and the DS side of the node
may be connected to Customer Premises Equipment (CPE) of
subscribers to the HFC. Amplifiers may be used in the node to
amplify upstream (US) signals and downstream (DS) signals.
Embodiments of the disclosure may provide an echo cancellation (EC)
process that may support full duplex (FDX) Data Over Cable Service
Interface Specification (DOCSIS) operation.
[0013] FIG. 1 is a block diagram of a system 100 for providing
proactive Echo Cancellation (EC) training consistent with
embodiments of the disclosure. System 100 may comprise a
Distributed Access Architecture (DAA). As shown in FIG. 1, system
100 may comprise a core 105, a remote PHY device (RPD) 110, and a
plurality of Customer Premises Equipment (CPE) 115. Core 105 may
comprise a Converged Cable Access Platform (CCAP) core and may
include a Cable Modem Termination System (CMTS) 120 that may
include a scheduler 125. RPD 110 may comprise an echo canceler 130.
Plurality of CPE 115 may comprise a first CPE 135 and a second CPE
140.
[0014] CMTS 120 may comprise a device located in a service
provider's (e.g., a cable company's) headend (i.e., core 105) that
may be used to provide high speed data services, such as cable
Internet or Voice-Over-Internet Protocol, to subscribers. Remote
physical layer (i.e., RPHY) may comprise shifting or distributing
the physical layer (i.e., PHY) of a conventional cable headend CMTS
to fiber nodes (e.g., RPD nodes) in a network. RPD 110 may comprise
circuity to implement the physical layer of the CMTS. First CPE 135
and second CPE 140 may comprise, but are not limited to, a Cable
Modem (CM), a cellular base station, a tablet device, a mobile
device, a smart phone, a telephone, a remote control device, a
set-top box, a digital video recorder, a personal computer, a
network computer, a mainframe, a router, or other similar
microcomputer-based device.
[0015] RPD 110 may comprise a node in an HFC network. RPD 110 may
comprise a container that may house optical and electrical
circuitry. An optical fiber cable 145 may be connected to one side
of RPD 110 and a plurality of coaxial cables 150 may be connected
to the other side of RPD 110. Optical fiber cable 145 may be
connected to CMTS 120 in core 105 in the HFC network. Plurality of
coaxial cables 150 may be connected to plurality of CPE 115 of
subscribers to the HFC. As such, RPD 110 may facilitate
communications between core 105 and plurality of CPE 115.
[0016] Elements described above of system 100 (e.g., RPD 110, CMTS
120, scheduler 125, echo canceler 130, first CPE 135, and second
CPE 140) may be practiced in hardware and/or in software (including
firmware, resident software, micro-code, etc.) or in any other
circuits or systems. Elements of system 100 may be practiced in
electrical circuits comprising discrete electronic elements,
packaged or integrated electronic chips containing logic gates, a
circuit utilizing a microprocessor, or on a single chip containing
electronic elements or microprocessors. Elements of system 100 may
also be practiced using other technologies capable of performing
logical operations such as, for example, AND, OR, and NOT,
including but not limited to, mechanical, optical, fluidic, and
quantum technologies. As described in greater detail below with
respect to FIG. 5, elements of system 100 may be practiced in a
computing device 500.
[0017] Consistent with embodiments of the disclosure, system 100
may support FDX DOCSIS operation. Echoes may occur in FDX DOCSIS
operations. Echo Cancellation (EC) (e.g., via echo canceler 130)
may be implemented for suppressing self-interference (e.g., from a
transmitter in RPD 110 to a receiver in RPD 110) to enable FDX
operations. CMTS 120 may ensure proper Echo Cancellation Training
(ECT) for echo canceler 130 to observe and characterize the echoes,
in order to derive EC coefficients.
[0018] ECT may be done during a "quiet period" during which there
may be no Upstream (US) transmissions, so the received US signal
may contain the echoes of the transmitted Downstream (DS) signal
and the channel noise. Such a quiet period may be referred to as an
ECT opportunity. Per the FDX DOCSIS 3.1 specification, an ECT
opportunity may cover an entire 96 MHz upstream channel and may
last one or multiple Orthogonal Frequency Division Multiple Access
(OFDMA) frames. Because the magnitude and phase of the echoes may
change over time (i.e., time varying channel), periodic ECT may be
used to maintain sufficient convergence of the EC. However, because
no US transmission may be permitted in an ECT opportunity, frequent
ECT incurs high bandwidth cost.
[0019] The FDX DOCSIS 3.1 specification defines reactive ECT
scheduling, where a CMTS schedules ECTs at a size and interval
based on the ECT requests from an echo canceler. In the DAA, the
CMTS US scheduler is located at the CCAP core, separated from the
echo canceler at the RPD over a Converged Interconnect Network
(CIN). Round Trip Time (RTT) over the CIN, may be in the order of
multiple milliseconds, causing delayed ECT training opportunities
that may result in echo cancellation divergence. This may be
problematic in cases where the channel experiences rapid changes
(e.g., wind blowing, heavy truck parking close to cable pedestal,
etc.). Consequently, there may be a need for frequent and always-on
ECT opportunities at a low bandwidth cost.
[0020] Embodiments of the disclosure may provide a proactive Echo
Cancellation Training (ECT) process that may provide always-on ECTs
and at low bandwidth cost. CMTS 120 may proactively schedule Echo
Cancellation Training Opportunities (ECTOs) without waiting for ECT
requests from echo canceler 130. ECTOs may be formed explicitly
with dedicated mini-slots, or implicitly when a grant is not used
or is partially used. For explicit ECTOs, CMTS 120 may restrict an
ECTO to one or a few mini-slots at low bandwidth cost. For example,
a one-mini-slot ECT may take 0.42% of the spectrum of a 96 MHz FDX
US channel.
[0021] CMTS 120 may achieve channel level ECT, for example, by
allocating mini-slot level ECTOs in nearly every frame with
different mini-slot offsets relative to the start of the channel
spectrum. Echo canceler 130 at RPD 110 may detect ECTOs in time and
frequency for constant EC training.
[0022] FIG. 2 is a flow chart setting forth the general stages
involved in a method 200 consistent with an embodiment of the
disclosure for providing proactive Echo Cancellation (EC) training.
Method 200 may be implemented using echo canceler 130 as described
in more detail above with respect to FIG. 1. Ways to implement the
stages of method 200 will be described in greater detail below.
[0023] Method 200 may begin at starting block 205 and proceed to
stage 210 where a plurality of Echo Cancellation Training
Opportunities (ECTOs) may be established. For example, ECTOs may
comprise Explicit Echo Cancellation Training Opportunity (EECTOs)
and Implicit Echo Cancellation Training Opportunity (IECTOs).
[0024] FIG. 3 illustrates EECTO scheduling. As shown in FIG. 3, an
EECTOs may comprise one or more mini-slots reserved for EC
training. Mini-slots included in an EECTO may be assigned, for
example, to NULL Service Flow Identifier (SID) or a designated SID
not used for any US transmissions.
[0025] CMTS 120 may limit the spectrum overhead by controlling the
number of mini-slots included in an EECTO. For example, a 1
mini-slot per frame EECTO may be equivalent to 1/237 (i.e., 0.42%)
of an 96 MHz FDX US channel bandwidth (a channel may have 237
mini-slots). EECTOs may be placed at different mini-slots, for
example, over consecutive frames. The time to cover a channel may
be referred to as an ECT cycle duration.
[0026] Under fast interference changing conditions, the ECT cycle
duration may be reduced with slight increase of the spectrum cost.
For example, at a 400 .mu.s frame size, the ECT cycle duration may
comprise 94.8 ms (i.e., 400 .mu.s.times.237) with 1 mini-slot for
EECTO per frame (i.e., spectrum overhead=0.42%). However, an ECT
cycle duration may comprise 9.48 ms with 10 mini-slots for EECTO
per frame (i.e., spectrum overhead=4.2%).
[0027] FIG. 4 illustrates IECTO scheduling. As shown in FIG. 4, an
IECTO may comprise an "accidental" ECTO, created whenever there may
be a gap between grants or when a grant is not fully used. This may
include: i) contention regions in an upstream bandwidth allocation
map provided to RPD 110 from scheduler 125; ii) guard time for
routine DOCSIS operations such as Upstream Channel Descriptor (UCD)
change, sounding, and Proactive Network Maintenance (PNM)
functions; and iii) unused or partially used data grants when the
grant size is bigger than a packet queue size at the CPE. FDX
DOCSIS may require a per CPE (e.g., Cable Modem (CM)) grant size to
be greater than a minimum grant bandwidth to meet fidelity
requirements. Predictive granting for low-latency service may
result in frequently unused grants.
[0028] Consistent with embodiments of the disclosure, IECTOs may
complement EECTOs and my provide additional EC training at no extra
spectrum overhead cost. Furthermore, CMTS 120 may shift the grant
locations, such that the subsequent grants end at different
mini-slot offsets in order to cover an entire channel frequency
spectrum over time. The potentially unused mini-slots may comprise
the remaining mini-slots at the end of a grant after a queue is
served.
[0029] From stage 210, where the plurality of ECTOs are
established, method 200 may advance to stage 220 where echo
canceler 130 may identify the plurality of ECTOs. For example, the
ECTOs may be referred to as "silent windows" or "quiet periods".
There may be several ways that RPD 110 (e.g., echo canceler 130 in
RPD 110) may detect silent windows. One way to detect silent
windows may be via a special SID. For example, scheduler 125 at
CMTS 120 may assign a special SID to mini-slots that may be
designated as a silent windows for ECT in the upstream bandwidth
allocation map that scheduler 125 may provide to RPD 110. RPD 110
may parse the upstream bandwidth allocation map to determine where
the silent windows are ahead of time. This can be used to identify
EECTOs as described above with respect to FIG. 3.
[0030] Another way to detect silent windows may be via power
detection. For example, RPD 110 may detect the power of mini-slots
at each frame, and based on the detected power, it may determine
that there are US signals at the mini-slot. This may be used to
identify either EECTOs or IECTOs.
[0031] Silent window detection via power detection may be described
as follows. Echo Cancellation (EC) coefficients, for example, may
be determined in the frequency domain for each and every subcarrier
(i.e., frequency domain EC). Echoes may be characterized by echo
canceler 130 with echo cancellation turned on. For example, echo
cancellation may be on once US traffic on the FDX band is turned
on. Thus, the EC coefficients may be determined as changes (i.e.,
deltas) except, for example, in the initial stage where the EC
coefficients may be set to zero.
[0032] For each subcarrier, embodiments of the disclosure may
determine the symbol power as follows: [0033]
p=sum(abs(si){circumflex over ( )}2), where si is the symbol level
on the subcarrier i, where i=1, 2, . . . N, where N is the frame
length. If p>p0i, this subcarrier may be skipped, if <p0i,
this may be an empty subcarrier, so its EC coefficients may be
determined and updated. Consistent with embodiments of the
disclosure, p0i may comprise a pre-determined threshold, for
example, for subcarrier i.
[0034] With echo cancellation turned on at echo canceler 130, the
Signal-to-Noise (SNR) of the US signal may, for example, be >25
dB, and may, for example, at least be >10 dB. Accordingly, there
may be a minimum 10 dB power jump after EC is turned on when there
is an US signal. Embodiments of the disclosure may set p0i as the
middle value of the average US signal power observed after EC on
subc i: [0035] P0i=N/2*P_ave_i; where P_ave_i is the average US
power observed after EC on subc i. N is the frame length.
[0036] To improve the robustness of silent window detection, the
detection may be done on a per mini-slot base. For each mini-slot,
embodiments of the disclosure may determine symbol power as
follows: [0037] p1=sum(abs(sij){circumflex over ( )}2), sij is the
symbol level on subcarrier i and on symbol j; i=1,2, . . . N,N is
the frame length, j=1,2, . . . , M, M is the mini-slot width If
p1>p10, skip all the subcarrier in this mini-slot, if p1<p10,
this is an empty mini-slot, the EC coefficient may be computed and
updated on every subcarrier within this MS. Embodiments of the
disclosure may set p10=N/2*P_ave_ms_i', where P_ave_ms_i' is the
average US power observed after EC on mini-slot i'. Accordingly,
silent window detection may involve power detection with minimum
overhead.
[0038] Compared to the special SID approach, the power detection
approach may have many benefits. For example, contention regions
may be utilized for ECT. Contention regions may be planned for
collision avoidance and low latency, thus the capacity may largely
be under-utilized, and most of time the contention regions may have
no signals. The power detection approach may detect if there are
contention signals, and if not, it may be utilized for ECT. As
another example, un-used mini-slots may be utilized for ECT. Some
mini-slots may be assigned to an SID (CM), but they may not be used
for various reasons (e.g., dropped MAP, scheduler does not schedule
them, CM may have no US data, etc.). Those un-used mini-slots may
be detected via power detection and used for ECT. As yet another
example, power detection approach may be used for both FDX RDP and
FDX amplifier. FDX amplifier may not have the capability to parse
an upstream bandwidth allocation map. The power detection approach
may be feasible for FDX amplifiers.
[0039] Once echo canceler 130 identifies the plurality of ECTOs in
stage 220, method 200 may continue to stage 230 where echo canceler
130 may conduct Echo Cancellation Training (ECT) for each of the
identified ECTOs. For example, EC coefficients may be determined
for each subcarrier in a mini-slot within a silent window as
coefficient changes (i.e., deltas). Once they are determined, the
EC coefficients changes may be used to update EC coefficients used
by echo canceler 130 through a rolling or a synchronizing process.
With the rolling process, for each mini-slot, once its EC
coefficient changes are obtained, embodiments of the disclosure may
use them to update the current EC coefficients, and apply the new
EC coefficients by echo canceler 130 in the next frame. However,
with the synchronizing process, embodiments of the disclosure may
wait until the EC coefficients of all the mini-slots have been
updated, and apply the new EC coefficients of all the subcarrier at
once by echo canceler 130. The synchronizing approach may reduce
data interruptions. After echo canceler 130 conducts ECT for each
of the identified ECTOs in stage 230, method 200 may then end at
stage 240.
[0040] For FDX systems, embodiments of the disclosure may provide
echo cancellation performed in the frequency domain on each
subcarrier on each active mini-slot. Embodiments of the disclosure
may comprise an echo cancellation training scheme that uses, in an
FDX system, EECTOs that may comprise a pattern of mini-slots in two
dimension time-frequency space in which the pattern of mini-slots
may have equal or close to equal coverage of each active mini-slots
and where the pattern of mini-slots may be dynamically adjusted
based on channel conditions and per request.
[0041] In addition, embodiments of the disclosure may comprise an
echo cancellation training scheme that uses, in an FDX system,
IECTOs that may comprise mini-slots that may be assigned for US
traffic, but may not be used by CPEs for US traffic. The IECTOs may
include contention regions, un-used mini-slots, and un-assigned
mini-slots. Scheduler 125 may schedule US allocation in such a way
that these IECTOs may have equal or close to equal coverage of each
active mini-slots.
[0042] Embodiments of the disclosure my provide, for an FDX system,
echo canceler 130 that may parse an upstream bandwidth allocation
map provided by scheduler 125, identify EECTOs, and conduct ECT on
the identified EECTOs. In addition, embodiments of the disclosure
my provide, for an FDX system, echo canceler 130 that may detect
the US power of the each subcarrier, tag the subcarrier as an IECTO
when the detected power is less than a pre-determined threshold,
and conduct ECT on the identified ECT opportunities. Moreover,
embodiments of the disclosure my provide, for an FDX system, echo
canceler 130 that may detect the US power of each mini-slot, tag
the mini-slot as an IECTO when the detected power is less than the
pre-determined threshold, and conduct ECT on the identified ECT
opportunities.
[0043] FIG. 5 shows computing device 500. As shown in FIG. 5,
computing device 500 may include a processing unit 510 and a memory
unit 515. Memory unit 515 may include a software module 520 and a
database 525. While executing on processing unit 510, software
module 520 may perform, for example, processes for providing
proactive Echo Cancellation (EC) training, including for example,
any one or more of the stages from method 200 described above with
respect to FIG. 2. Computing device 500, for example, may provide
an operating environment for RPD 110, CMTS 120, scheduler 125, echo
canceler 130, first CPE 135, and second CPE 140. RPD 110, CMTS 120,
scheduler 125, echo canceler 130, first CPE 135, and second CPE 140
may operate in other environments and is not limited to computing
device 500.
[0044] Computing device 500 may be implemented using a Wireless
Fidelity (Wi-Fi) access point, a cellular base station, a tablet
device, a mobile device, a smart phone, a telephone, a remote
control device, a set-top box, a digital video recorder, a cable
modem, a personal computer, a network computer, a mainframe, a
router, a switch, a server cluster, a smart TV-like device, a
network storage device, a network relay devices, or other similar
microcomputer-based device. Computing device 500 may comprise any
computer operating environment, such as hand-held devices,
multiprocessor systems, microprocessor-based or programmable sender
electronic devices, minicomputers, mainframe computers, and the
like. Computing device 500 may also be practiced in distributed
computing environments where tasks are performed by remote
processing devices. The aforementioned systems and devices are
examples and computing device 500 may comprise other systems or
devices.
[0045] Embodiments of the disclosure, for example, may be
implemented as a computer process (method), a computing system, or
as an article of manufacture, such as a computer program product or
computer readable media. The computer program product may be a
computer storage media readable by a computer system and encoding a
computer program of instructions for executing a computer process.
The computer program product may also be a propagated signal on a
carrier readable by a computing system and encoding a computer
program of instructions for executing a computer process.
Accordingly, the present disclosure may be embodied in hardware
and/or in software (including firmware, resident software,
micro-code, etc.). In other words, embodiments of the present
disclosure may take the form of a computer program product on a
computer-usable or computer-readable storage medium having
computer-usable or computer-readable program code embodied in the
medium for use by or in connection with an instruction execution
system. A computer-usable or computer-readable medium may be any
medium that can contain, store, communicate, propagate, or
transport the program for use by or in connection with the
instruction execution system, apparatus, or device.
[0046] The computer-usable or computer-readable medium may be, for
example but not limited to, an electronic, magnetic, optical,
electromagnetic, infrared, or semiconductor system, apparatus,
device, or propagation medium. More specific computer-readable
medium examples (a non-exhaustive list), the computer-readable
medium may include the following: an electrical connection having
one or more wires, a portable computer diskette, a random access
memory (RAM), a read-only memory (ROM), an erasable programmable
read-only memory (EPROM or Flash memory), an optical fiber, and a
portable compact disc read-only memory (CD-ROM). Note that the
computer-usable or computer-readable medium could even be paper or
another suitable medium upon which the program is printed, as the
program can be electronically captured, via, for instance, optical
scanning of the paper or other medium, then compiled, interpreted,
or otherwise processed in a suitable manner, if necessary, and then
stored in a computer memory.
[0047] While certain embodiments of the disclosure have been
described, other embodiments may exist. Furthermore, although
embodiments of the present disclosure have been described as being
associated with data stored in memory and other storage mediums,
data can also be stored on or read from other types of
computer-readable media, such as secondary storage devices, like
hard disks, floppy disks, or a CD-ROM, a carrier wave from the
Internet, or other forms of RAM or ROM. Further, the disclosed
methods' stages may be modified in any manner, including by
reordering stages and/or inserting or deleting stages, without
departing from the disclosure.
[0048] Furthermore, embodiments of the disclosure may be practiced
in an electrical circuit comprising discrete electronic elements,
packaged or integrated electronic chips containing logic gates, a
circuit utilizing a microprocessor, or on a single chip containing
electronic elements or microprocessors. Embodiments of the
disclosure may also be practiced using other technologies capable
of performing logical operations such as, for example, AND, OR, and
NOT, including but not limited to, mechanical, optical, fluidic,
and quantum technologies. In addition, embodiments of the
disclosure may be practiced within a general purpose computer or in
any other circuits or systems.
[0049] Embodiments of the disclosure may be practiced via a
system-on-a-chip (SOC) where each or many of the components
illustrated in FIG. 1 may be integrated onto a single integrated
circuit. Such an SOC device may include one or more processing
units, graphics units, communications units, system virtualization
units and various application functionality all of which may be
integrated (or "burned") onto the chip substrate as a single
integrated circuit. When operating via an SOC, the functionality
described herein with respect to embodiments of the disclosure, may
be performed via application-specific logic integrated with other
components of computing device 500 on the single integrated circuit
(chip).
[0050] Embodiments of the present disclosure, for example, are
described above with reference to block diagrams and/or operational
illustrations of methods, systems, and computer program products
according to embodiments of the disclosure. The functions/acts
noted in the blocks may occur out of the order as shown in any
flowchart. For example, two blocks shown in succession may in fact
be executed substantially concurrently or the blocks may sometimes
be executed in the reverse order, depending upon the
functionality/acts involved.
[0051] While the specification includes examples, the disclosure's
scope is indicated by the following claims. Furthermore, while the
specification has been described in language specific to structural
features and/or methodological acts, the claims are not limited to
the features or acts described above. Rather, the specific features
and acts described above are disclosed as example for embodiments
of the disclosure.
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