U.S. patent application number 15/907918 was filed with the patent office on 2018-07-05 for method and system for a low-power client in a wide area network.
The applicant listed for this patent is Maxlinear, Inc.. Invention is credited to Timothy Gallagher, Curtis Ling, Sridhar Ramesh.
Application Number | 20180191486 15/907918 |
Document ID | / |
Family ID | 48085929 |
Filed Date | 2018-07-05 |
United States Patent
Application |
20180191486 |
Kind Code |
A1 |
Ling; Curtis ; et
al. |
July 5, 2018 |
Method and System for a Low-Power Client in a Wide Area Network
Abstract
A network device coupled to a network may be operable to receive
an indication from the network that media access control (MAC)
management messages will be transmitted by the network at fixed
intervals. Subsequent to receiving the indication, the network
device may be operable to power down one or more components of the
network device and set a sleep timer to a value equal to an integer
multiple of the fixed interval minus a transition period. The
network device may power up the one or more components of the
network device upon expiration of the sleep timer. The network
device may power up the one or more components of the network
device upon an amount of traffic in a buffer of the network device
reaching a threshold.
Inventors: |
Ling; Curtis; (Carlsbad,
CA) ; Gallagher; Timothy; (Carlsbad, CA) ;
Ramesh; Sridhar; (Carlsbad, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Maxlinear, Inc. |
Carlsbad |
CA |
US |
|
|
Family ID: |
48085929 |
Appl. No.: |
15/907918 |
Filed: |
February 28, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15244674 |
Aug 23, 2016 |
9912466 |
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15907918 |
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13866205 |
Apr 19, 2013 |
9426734 |
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15244674 |
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13553175 |
Jul 19, 2012 |
8711750 |
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13866205 |
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61547663 |
Oct 14, 2011 |
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61555550 |
Nov 4, 2011 |
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61569346 |
Dec 12, 2011 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02D 10/157 20180101;
G06F 1/3278 20130101; H04L 7/0033 20130101; Y02D 10/00 20180101;
H04W 52/02 20130101; Y02D 30/50 20200801; Y02D 50/20 20180101; G06F
1/3209 20130101; G06F 1/3234 20130101; Y02D 70/168 20180101; Y02D
30/70 20200801; H04L 12/2801 20130101 |
International
Class: |
H04L 7/00 20060101
H04L007/00; H04L 12/28 20060101 H04L012/28; G06F 1/32 20060101
G06F001/32; H04W 52/02 20060101 H04W052/02 |
Claims
1. A method comprising: in a network device coupled to a network:
receiving an indication from said network that contention
opportunities will occur at predetermined intervals; transitioning
to a power-saving mode in which one or more components of said
network device are powered down; transitioning out of said
power-saving mode during one of said predetermined intervals, and
periodically while operating in said power-saving mode, powering up
one or more of said components, resynchronizing to a signal from
said network, and again powering down said one or more of said
components.
2. The method of claim 1, wherein said network device is a cable
modem, cable set-top-box, or cable gateway.
3. The method of claim 1, wherein said indication is in response to
a request sent by said network device.
4. The method of claim 1, wherein said one or more components
comprise an amplifier, a mixer, a filter, a data converter, a
modulator, and/or a demodulator.
5. The method of claim 1, wherein said one or more components
comprise a media access controller.
6. The method of claim 1, wherein said network device is operable
to determine said predetermined time intervals based on past
traffic statistics and/or patterns.
7. The method of claim 1, wherein said network device does not
listen to communications from said network while in said
power-saving mode.
8. The method of claim 1, comprising, subsequent to receiving said
indication, setting a sleep timer to a value that is determined
based on drift of one or more clocks of said network device.
9. A system comprising: circuitry for use in a network device
coupled to a network, said circuitry being operable to: receive an
indication from said network that contention opportunities will
occur at predetermined intervals; transitioning to a power-saving
mode in which one or more portions of said circuitry are powered
down; transition out of said power-saving mode during one of said
intervals, and periodically while operating in said power-saving
mode, power up said one or more portions of said circuitry,
resynchronize to a signal from said network, and again power down
said one or more portions of said circuitry.
10. The system of claim 9, wherein said network device comprises a
cable modem, cable set-top-box, or cable gateway.
11. The system of claim 9, wherein said indication is in response
to a request sent by said network device.
12. The system of claim 9, wherein said one or more portions of
said circuitry comprise an amplifier, a mixer, a filter, a data
converter, a modulator, and/or a demodulator.
13. The system of claim 9, wherein said one or more portions of
said circuitry comprise a media access controller.
14. The system of claim 9, wherein said network device is operable
to determine said predetermined time intervals based on past
traffic statistics and/or patterns.
15. The system of claim 9, wherein said network device does not
listen to communications from said network while in said
power-saving mode.
16. The system of claim 9, wherein said circuitry is operable to,
subsequent to reception of said indication, set a sleep timer to a
value that is determined based on drift of one or more clocks of
said network device.
Description
CLAIM OF PRIORITY
[0001] This patent application is a continuation of U.S. patent
application Ser. No. 15/244,674 filed on Aug. 23, 2016, which is a
continuation of U.S. patent application Ser. No. 13/866,205, now
U.S. Pat. No. 9,426,734, filed on Apr. 19, 2013, which is a
divisional of U.S. patent application Ser. No. 13/553,175, now U.S.
Pat. No. 8,711,750, filed in response to a restriction/election
requirement. U.S. patent application Ser. No. 13/553,175, in turn,
makes reference to, claims priority to and claims benefit from U.S.
Provisional Patent Application Ser. No. 61/547,663 filed on Oct.
14, 2011; U.S. Provisional Patent Application Ser. No. 61/555,550
filed on Nov. 4, 2011; and U.S. Provisional Patent Application Ser.
No. 61/569,346 filed on Dec. 12, 2011.
[0002] Each of the above applications is hereby incorporated herein
by reference in its entirety.
FIELD OF THE INVENTION
[0003] Certain embodiments of the invention relate to networking.
More specifically, certain embodiments of the invention relate to a
method and system for a low-power client in a wide area
network.
INCORPORATION BY REFERENCE
[0004] This patent application also makes reference to: [0005] U.S.
patent application Ser. No. 13/485,034 entitled "Method and System
for Server-Side Message Handling in a Low-Power Wide Area Network,"
and filed on May 31, 2012; [0006] U.S. patent application Ser. No.
13/553,328 entitled "Method and System for Client-Side Message
Handling in a Low-Power Wide Area Network," and filed on Jul. 19,
2012; and [0007] U.S. patent application Ser. No. 13/553,195
(attorney docket No. 24760US02) entitled "Method and System for
Server-Side Handling of a Low-Power Client in a Wide Area Network,"
and filed on Jul. 19, 2012.
[0008] Each of the above applications is hereby incorporated herein
by reference in its entirety.
BACKGROUND OF THE INVENTION
[0009] Existing wide area networks consume too much power. Further
limitations and disadvantages of conventional and traditional
approaches will become apparent to one of skill in the art, through
comparison of such systems with some aspects of the present
invention as set forth in the remainder of the present application
with reference to the drawings.
BRIEF SUMMARY OF THE INVENTION
[0010] An system and/or method is provided for a Low-Power Client
in a Wide Area Network, substantially as illustrated by and/or
described in connection with at least one of the figures, as set
forth more completely in the claims.
[0011] These and other advantages, aspects and novel features of
the present invention, as well as details of an illustrated
embodiment thereof, will be more fully understood from the
following description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 depicts an exemplary DOCSIS network which may take
advantage of aspects of the invention.
[0013] FIG. 2 depicts a cable modem as an example of customer
premise equipment (CPE).
[0014] FIG. 3 depicts a cable set-top box as an example of customer
premise equipment (CPE).
[0015] FIG. 4 depicts a cable gateway as an example of customer
premise equipment (CPE).
[0016] FIG. 5A depicts an exemplary physical layer transceiver
(PHY) of a CPE which supports low-power wide area networking.
[0017] FIG. 5B depicts components of a receive chain of an
exemplary PHY.
[0018] FIG. 5C depicts components of a transmit chain of an
exemplary PHY.
[0019] FIG. 6 illustrates a media access controller of an exemplary
CPE.
[0020] FIGS. 7A and 7B illustrate a transition to a state in which
MAC management messages are transmitted at predetermined
intervals.
[0021] FIGS. 8A and 8B illustrate activity on a network channel
before and during a CPE entering a power-saving state.
[0022] FIG. 9 is a flowchart illustrating exemplary steps for
managing a power-saving state in a client device of a wide area
network.
[0023] FIG. 10 is a flowchart illustrating exemplary steps for
managing a power-saving state in a client device of a wide area
network.
DETAILED DESCRIPTION OF THE INVENTION
[0024] As utilized herein the terms "circuits" and "circuitry"
refer to physical electronic components (i.e. hardware) and any
software and/or firmware ("code") which may configure the hardware,
be executed by the hardware, and or otherwise be associated with
the hardware. As utilized herein, "and/or" means any one or more of
the items in the list joined by "and/or". As an example, "x and/or
y" means any element of the three-element set {(x), (y), (x, y)}.
As another example, "x, y, and/or z" means any element of the
seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y,
z)}. As utilized herein, the terms "block" and "module" refer to
functions than can be implemented in hardware, software, firmware,
or any combination of one or more thereof. As utilized herein, the
term "exemplary" means serving as a non-limiting example, instance,
or illustration. As utilized herein, the term "e.g.," introduces a
list of one or more non-limiting examples, instances, or
illustrations.
[0025] FIG. 1 depicts an exemplary DOCSIS network which may take
advantage of aspects of the present invention. Shown in FIG. 1 is a
terrestrial television antenna 102, a satellite dish 104, an
Internet Protocol (IP) network 106, a headend 108, a wide area
network (e.g., hybrid fiber-coaxial (HFC) network) 118, a gateway
120, end systems 126a and 126b (e.g., computers), end systems 128a
and 128b (e.g., televisions), a cable modem 122b, and a set-top box
124b. The headend 108 comprises a switch 110, a video modulator
112, a cable modem termination system (CMTS) 114, and a
splitter/combiner 116. The gateway 120 may be an instance of the
gateway 120 described below with respect to FIG. 4, and may
comprise a cable modem module 122a, and a set-top box module 124a.
Each of cable modems 122a and 122b may be an instance of the cable
modem module 122 described with respect to FIG. 2. Each of set-top
boxes 124a and 124b may be an instance of the set-top box module
124 described with respect to FIG. 3.
[0026] For downstream traffic, the headend 108 may receive
television signals via the antenna 102 and the satellite dish 104,
and may receive data via the IP network 106. The switch 110 may
convey the television signals to the video modulator 112 and the
data to the CMTS 114. The video modulator 112 may modulate the
received television signals onto a carrier. The CMTS 114 may
modulate the received data onto a carrier. The splitter/combiner
116 may combine the outputs of the video modulator 112 and the CMTS
114 and output the combined signal onto the wide area network (WAN)
118 for distribution to CPE. The cable modems 122a and 122b may
process the portion of the combined signal that carries the data
from the CMTS 114, and the set-top box modules 124a and 124b may
process the portion of the combined signal that carries the video
from the video modulator 112.
[0027] For upstream data, the end systems 126a and 126b may
transmit packets to the cable modem 122a and 122b, respectively,
which may then modulate the packets onto a carrier for transmission
via the WAN 118. The splitter/combiner 116 may then convey the data
to the CMTS 114. The CMTS 114 may process the data signals (e.g.,
verify that they came from a registered cable modem) and convey the
data to the IP network 106.
[0028] The CMTS 114 may manage connections to the cable modems 122a
and 122b. This may include, for example: participating in ranging
operations to control the power at which the cable modems 122a and
122b transmit; forwarding of dynamic host configuration protocol
(DHCP) messages between a DHCP server and the cable modems 122a and
122b; forwarding of time of day messages between a time of day
server and the cable modems 122a and 122b; and managing
registration of the cable modems 122a and 122b to grant the cable
modems network (e.g., Internet) access. The registration process
for a cable modem 122 may comprise the cable modem 122 sending a
registration request along with its configuration settings, and the
CMTS 114 accepting or rejecting the cable modem based on the
configuration settings. The registration process may additionally
comprise an exchange of security keys, certificates, or other
authentication information.
[0029] Conventionally, after a cable modem has successfully
registered with the CMTS 114, the CMTS 114 will deregister the
cable modem if the cable modem does not communicate with the CMTS
114 for a predetermined period of time. Accordingly, aspects of the
present invention may enable a cable modem 122 and the CMTS 114 to
coordinate the cable modem 122 operating in a low-power mode
("sleeping") without being deregistered by the CMTS 114. Such
coordination between the cable modem 122 and the CMTS 114 may be
accomplished through communication of one or more messages, as is
described, for example, with respect to FIG. 7A and/or FIG. 7B.
[0030] Aspects of the invention may enable media access planning in
a downstream direction. In this regard, the CMTS 114 may
communicate (e.g., via one or more messages) with CPEs (e.g., cable
modems) that it serves to coordinate when and how (e.g., on which
channel(s)) the CMTS 114 will communicate with the CPEs. Downstream
planning may enable a CPE to sleep until the next time at which the
plan requires it to listen on the channel(s).
[0031] Aspects of the invention may enable the CMTS 114 to dedicate
a timeslot for the transmission of messages to one or more sleeping
CPEs. The timeslot may occur at intervals that are independently
determinable by the one or more CPEs. That is, duration of the
intervals can be determined by each of the one or more CPEs without
those devices having to listen for messages outside of the
dedicated timeslot. In an example embodiment, such an interval may
be of a predetermined duration that is made known to the one or
more CPEs prior to the start of the timeslot. In another example
embodiment, the duration of such an interval may be determined
independently by each of the one or more CPEs while the interval is
in progress. In such an embodiment, the determination may be based
on context information (e.g., time of day, previous traffic, etc.)
available to the one or more CPEs. Such a scheme may be analogous
to an unsolicited grant service, but in the downstream direction.
Accordingly, a CPE (e.g., cable modem 122, set-top box 124, or
gateway 120) may sleep for one or more of the intervals between
occurrences of the timeslot, wake up and listen to the channel
during the timeslot, and then go back to sleep. Such dedicated
timeslots in the downstream direction may coincide in time with,
and/or have an independently determinable time relationship (e.g.,
a predetermined, fixed time relationship) to, unsolicited grants in
the upstream direction. In this manner, if there is no upstream
activity during the corresponding unsolicited grant, then
adjustments may be made to, for example, the duration of the
timeslot, the interval between occurrences of the timeslot, etc.
The messages communicated during occurrences of the timeslot may,
for example, contain wake up messages. As another example, the
messages communicated during occurrences of the timeslot may
comprise data communicated to and/or from "always on" end systems
(e.g., appliances, utility meters, etc.) that may need to
communicate over the WAN via a CPE even when the CPE is in a
power-save mode.
[0032] In an embodiment of the invention, one or more logical
channels may be dedicated for the communication of messages (e.g.,
messages pertaining to power management) and/or for the
communication of traffic to "always-on" end systems, even when a
CPE via which the "always-on" end system communicates is in a
power-saving mode. For example, in systems utilizing DVB-C2 or
DVB-T2, such traffic can be mapped to a dedicated physical layer
pipe.
[0033] FIG. 2 depicts a cable modem as an example of customer
premise equipment (CPE). The cable modem 122 comprises a physical
layer transceiver (PHY) module 202, DOCSIS medium access controller
(MAC) module 204, Ethernet MAC/PHY module 206, a TCP/IP stack
module 208, a conditional access module 210, and a host 218
comprising a CPU 216 and memory module 214 which interoperate to
execute applications/processes 212.
[0034] The PHY module 202 may be operable to receive digital
signals from the MAC 204, generate corresponding analog symbols,
and transmit the symbols onto the WAN 118. Similarly, the PHY
module 202 may be operable to receive analog symbols over the WAN
118, convert the symbols to digital signals, and convey the digital
signals to the MAC module 204. The PHY module 202 may be an
instance of the PHY module 500 described below with respect to FIG.
5A. The MAC module 204 may be operable to implement DOCIS media
access control protocol(s) for regulating when and/or how the cable
modem 122 transmits on the WAN 118. The Ethernet MAC/PHY module 206
may be operable to implement Ethernet physical layer and data link
layer protocols such that the cable modem 220 may transmit and
receive via an Ethernet local area network (LAN). The TCP/IP stack
module 208 may be operable to implement functionality of OSI layers
3 and higher layers to enable the host 218 to communicate via the
WAN 118 and/or the LAN. The conditional access module 210 may be
operable to prevent the host from transmitting and/or receiving
DOCSIS traffic via the WAN 118 if the cable modem 122 is not
subscribed to such services. The CPU 216 may execute instructions
stored in the memory module 214 and store run-time data in the
memory module 214 to execute various processes and/or applications
(e.g., an operating system).
[0035] In operation, if and/or when the cable modem 122 operate in
a power-saving mode (a mode in which one or more of its components
normally used for transmission and/or reception are powered down)
may be controlled based on a variety of factors such as, for
example, statistics and/or patterns of traffic in the network,
number and/or types of devices in the premises served via the modem
122, and/or input from a user in the premises served via the modem
122. Such components may comprise a media access controller (or
portions thereof) of the cable modem 122 and/or a PHY (or portions
thereof) of the cable modem 122. Transitions into and/or out of a
power-saving mode may be coordinated via an exchange of messages
such as, for example, described below in FIGS. 7A and 7B.
[0036] FIG. 3 depicts a cable set-top box as an example of customer
premise equipment (CPE). The set-top box 124 comprises a physical
layer transceiver (PHY) module 302, a conditional access module
304, an MPEG decoder module 306, audio digital-to-analog converter
(DAC) module 308, and video encoder module 310.
[0037] The PHY module 302 may be operable to receive analog symbols
over the WAN 118, convert the symbols to digital signals, and
convey the digital signals to the MAC module 204. The PHY module
302 may be an instance of the PHY module 500 described below with
respect to FIG. 5A. The conditional access module 304 may be
operable to prevent the set-top box 124 from decoding audio/video
content to which it is not subscribed. The MPEG decoder module 306
may be operable to decode MPEG streams carried in the signal
received via the WAN 118. The Audio DAC module 308 may be operable
to convert one or more digital audio signals output by the MPEG
decoder 306 into an analog signal for output to one or more
speakers. The video encoder 310 may be operable to output one or
more digital video signals output by the MPEG decoder 306 according
to one or more video protocols such as HDMI or DisplayPort.
[0038] In operation, if and/or when the set-top box 124 operates in
a power-saving mode (a mode in which one or more of its components
normally used for transmission and/or reception are powered down)
may be controlled based on a variety of factors such as, for
example, statistics and/or patterns of traffic in the network,
number and/or types of devices in the premises served via the
set-top box 124, and/or input from a user in the premises served
via the set-top box 124. Such components may comprise a media
access controller (or portions thereof) of the set-top box 124
and/or a PHY (or portions thereof) of the set-top box 124.
Transitions into and/or out of a power-saving mode may be
coordinated via an exchange of messages such as, for example,
described below in FIGS. 7A and 7B.
[0039] FIG. 4 depicts a cable gateway as an example of customer
premise equipment (CPE). The gateway 120 comprises a PHY module
402, a DOCSIS MAC module 404, a conditional access module 406, a
host controller module 408, an Ethernet MAC/PHY module 410, an MPEG
decoder module 412, a video encoder module 414, and an audio DAC
module 416.
[0040] The PHY module 402 may be operable to receive digital
signals from the MAC 404, generate corresponding analog symbols,
and transmit the symbols onto the WAN 118. Similarly, the PHY
module 402 may be operable to receive analog symbols over the WAN
118, convert the symbols to digital signals, and convey the digital
signals to the MAC module 404. The PHY module 402 may be an
instance of the PHY module 500 described below with respect to FIG.
5A. The MAC module 404 may be operable to implement DOCIS media
access control protocol(s) for regulating when and/or how the
gateway 120 transmits on the WAN 118. The conditional access module
406 may be operable to prevent the gateway 120 from decoding
audio/video content and/or data to which it is not subscribed. The
host controller module 408 may be operable to implement OSI layer 3
and higher OSI layers to enable communication between the WAN 118
and the LAN network via the Ethernet MAC/PHY module 410. The
Ethernet MAC/PHY module 410 may be operable to implement Ethernet
physical layer and data link layer protocols such that the gateway
120 may transmit and receive via an Ethernet local area network
(LAN). The MPEG decoder module 412 may be operable to decode MPEG
streams carried in the signal received via the WAN 118. The Audio
DAC module 416 may be operable to convert one or more digital audio
signals output by the MPEG decoder 412 into an analog signal for
output to one or more speakers. The video encoder 414 may be
operable to output one or more digital video signals output by the
MPEG decoder 412 according to one or more video protocols such as
HDMI or DisplayPort.
[0041] In operation, if and/or when the gateway 120 operates in a
power-saving mode (a mode in which one or more of its components
normally used for transmission and/or reception are powered down)
may be controlled based on a variety of factors such as, for
example, statistics and/or patterns of traffic in the network,
number and/or types of devices in the premises served via the
gateway 120, and/or input from a user in the premises served via
the gateway 120. Such components may comprise a media access
controller (or portions thereof) of the gateway 120 and/or a PHY
(or portions thereof) of the gateway 120. Transitions into and/or
out of a power-saving mode may be coordinated via an exchange of
messages such as, for example, described below in FIGS. 7A and
7B.
[0042] FIG. 5A depicts an exemplary physical layer transceiver
(PHY) of a CPE which supports low-power wide area networking. The
PHY 500 comprises an analog front end (AFE) 502, a transmit chain
504, a receive chain 506, a clock module 526, and a memory module
528 for storing timing and/or state information.
[0043] For receive operations, the AFE 502 may be operable to
amplify an analog signal received via the WAN 118, down-convert the
received signal, filter the received signal, convert the filtered
signal to a digital representation, and convey the digital signal
to the demodulator 506. For transmit operations, the AFE 502 may be
operable to receive a digital signal from the transmit chain 504,
convert the digital signal to an analog representation, filter the
analog signal, up-convert the signal, and amplify the signal for
transmission onto the WAN 118. The AFE 502 may for example,
comprise components 552-558 described below with respect to FIG. 5B
and components 572-578 described below with respect to FIG. 5C.
[0044] The transmit chain 504 may be operable to perform operations
to support transmission of data onto the WAN 118. Such operations
may comprise encoding, modulating, converting to analog, filtering,
and/or amplifying a signal received from higher OSI layers. In an
exemplary embodiment of the invention, the Tx chain 504 may
comprise one or more buffers 510 which may be operable to store
data to be transmitted while the CPE in which the PHY resides is in
a power-saving state.
[0045] The receive chain 504 may be operable to perform operations
to support reception of data onto the WAN 118. Such operations may
comprise amplifying, demodulating, filtering, converting to
digital, and/or decoding a signal received from the physical medium
(e.g., coaxial cable). In an exemplary embodiment of the invention,
the Rx chain 506 may comprise one or more buffers 512 which may be
operable to store received data while the CPE in which the PHY
resides is in a power-saving state.
[0046] The clock module 526 may be operable to generate one or more
oscillating signals for synchronizing circuitry of the PHY 500
and/or for keeping track of time. The clock module 526 may, for
example, comprise a real time clock that enables scheduling events
such as transitions into and out of a power-saving mode of
operation and/or keeping track of when MAC management messages,
contention opportunities, and/or unsolicited upstream and/or
downstream grants will occur.
[0047] The memory module 528 may be operable to store timing
information such as: times at which the CPE is to transition
between different modes of operation, amount of time the CPE has
been in a particular mode of operation, times at which a message
was received, times at which a message is expected, etc.
Additionally or alternatively, the memory module 528 may store
state information that may enable the PHY 500 to quickly resume
communications upon waking from a power-saving mode. Such state
info may comprise, for example, upstream frequency to utilize for
transmission, frequency on which to listen for reception, symbol
rate at which to transmit, modulation profile, carrier offset,
equalizer/filter settings, and/or gain settings. In an exemplary
embodiment of the invention, before components of a CPE (e.g., a
MAC of the CPE or portions of the CPE's PHY) go to sleep, those
components may store state information to the module 528. This
information may be utilized upon the components waking from the
power-saving mode to reduce the time necessary for the components
to be ready to receive data from the WAN 118.
[0048] FIG. 5B depicts components of a receive chain of an
exemplary PHY. The receive chain 500 comprises the following
components: a low noise amplifier (LNA) module 552, a mixer module
554, a filter module 556, an analog-to-digital converter (ADC) 558,
and a demodulator 560.
[0049] The low noise amplifier (LNA) 552 may be operable to amplify
signals received via the WAN 118. The mixer 554 may be operable
down-convert received signals. The filter 556 may be operable to
select one or more sub-bands of the received, down-converted
signal. The analog-to-digital converter (ADC) 558 may be operable
to convert the analog signal output by filter 706 to a digital
representation. The demodulator 560 may be operable to demodulate
the digital signal from the ADC 558 to recover an MPEG transport
stream (MPEG-TS) contained therein.
[0050] In operation, a mode of operation of various components
(e.g., amplifier 552, mixer 554, filter 556, data converter 558,
and demodulator 560) of the receive chain 550 may be controlled
based on whether the CPE in which the receive chain 550 resides is
in a power-saving mode. While in the power-saving mode, one or more
of the components may be powered-down. A component may be
powered-down by, for example, reducing a supply voltage and/or
supply current provided to the component and/or reducing the
frequency of a clock signal input to the component. Additionally or
alternatively, components may be powered down by configuring them
into a different mode of operation. For example, the number of
poles of the filter 556 may be reduced, the resolution of the ADC
558 may be reduced, the gain and/or linearity of the amplifier 552
may be reduced, the demodulator 560 may be configured to process
low-order modulation schemes, etc. The configuration of the
components may be controlled via the management bus 530.
[0051] FIG. 5C depicts components of a transmit chain of an
exemplary PHY. The transmit chain 570 comprises a power amplifier
(PA) module 572, a mixer module 574, a filter module 576, a
digital-to-analog converter (DAC) 578, and a modulator 580.
[0052] The power amplifier (PA) 572 may be operable to amplify
signals for transmission onto the WAN 118. The mixer 574 may be
operable up-convert signals to be transmitted. The filter 576 may
be operable to filter out undesired signals output by the DAC 578.
The DAC 578 may be operable to convert the digital signal output by
modulator 580 to an analog representation. The modulator 580 may be
operable to modulate a MPEG transport stream onto one or more
carriers.
[0053] In operation, a mode of operation of various components
(e.g., amplifier 572, mixer 574, filter 576, data converter 578,
and modulator 580) of the transmit chain 570 may be controlled
based on whether the CPE in which the transmit chain 570 resides is
in a power-saving mode. While in the power-saving mode, one or more
of the components may be powered-down. A component may be
powered-down by, for example, reducing a supply voltage and/or
supply current provided to the component and/or reducing the
frequency of a clock signal input to the component. Additionally or
alternatively, components may be powered down by configuring them
into a different mode of operation. For example, the number of
poles of the filter 576 may be reduced, the resolution of the ADC
578 may be reduced, the gain and/or linearity of the amplifier 572
may be reduced, the demodulator 580 may be configured to process
low-order modulation schemes, etc. The configuration of the
components may be controlled via the management bus 530.
[0054] FIG. 6 illustrates a media access controller of an exemplary
CPE. The MAC 610 may be capable of operating in multiple modes of
operation, with different modes of operation being characterized by
different power consumption. In an exemplary embodiment, the MAC
610 may support a "normal" mode characterized by higher power
consumption and a "sleep" mode characterized by lower power
consumption, and may occasionally and/or periodically be put into
the sleep mode to reduce power consumption.
[0055] In some instances, the PHY (e.g., PHY 500) of a CPE may
operate in a higher-power mode (i.e., be "awake") while the MAC
(e.g., MAC 610) of the CPE remains in a low-power mode (i.e., be
"asleep"). During such times, the PHY may resynchronize a clock
utilized for transmitting signals onto the WAN 118 to the clock
utilized for receiving signals via the WAN 118. Such
synchronization may reduce the time needed to be ready to transmit
upon the MAC transitioning out of the low-power mode.
[0056] In an exemplary embodiment of the invention, channel bonding
as enabled in DOCSIS 3.0 may be controlled in coordination with the
sleep cycle of the CPE. For example, while awake, a CPE may receive
and/or transmit on multiple channels, but while in a sleep mode,
only one channel may be allocated for the CPE (the one channel
could also be, for example, shared among multiple sleeping CPEs).
Communications (e.g., MAC management messages and/or other
specialized messages or signals) between the CMTS 114 and the CPE
in which the AMC 610 resides may coordinate channel bonding.
[0057] FIGS. 7A and 7B illustrate a transition to a state in which
MAC management messages are transmitted at predetermined intervals.
Referring to FIGS. 7A and 7B, there is shown MAP messages n-6
through n communicated at non-independently-determinable intervals.
That is, from the cable modem's perspective the duration of each of
the intervals (t3-t1), (t5-t3), (t7-t5), and (t9-t7) are random
and, thus the cable modem has to continuously listen. At time t13,
however, the cable modem sends a request that it be permitted to
enter a power-saving mode of operation. The message may be, for
example, a MAC management message wherein the contents of its Type
Value field are uniquely associated with a sleep request.
[0058] At time t15, the CMTS responds with a message granting the
cable modem permission to sleep. The CMTS may determine to grant
the request based on various considerations such as network
traffic, type(s) of devices in the network. The message granting
the sleep request may also include parameters such as how long the
cable modem is permitted to sleep, whether the cable modem must
listen for messages while it is sleeping, the timing of MAC
management messages, contention periods, and/or timeslots reserved
for the cable modem while the modem is sleeping, etc.
[0059] Subsequent to the grant at time t15, the CMTS may send MAP
messages at independently determinable intervals until the modem
transitions out of the power-saving mode back to a normal mode of
operation. That is, the duration of each of the intervals
(t19-t17), (t21-t19), and (t23-t21) is either predetermined and
known to the cable modem prior to the start of the interval, or
determinable from context during the interval (without the cable
modem having to listen during the interval). In the example
embodiment depicted, each of the intervals (t19-t17), (t21-t19),
and (t23-t21) are of a common, predetermined duration. While in the
power-saving mode, the cable modem may track time such that it
knows when the next MAP message will be sent. In this manner,
should the cable modem desire, it can transition out of the
power-saving state just in time to hear the MAP message, receive
and process the MAP message, and then return to the power-saving
state immediately thereafter.
[0060] FIGS. 8A and 8B illustrate activity on a network channel
before and during a CPE entering a power-saving state. Shown in
these two figures is activity on an exemplary WAN channel. During
timeslots 802, MAC management messages, such as UCD, SYNC, and/or
MAP messages, may be transmitted by the CMTS. The timeslots 804 may
correspond to, for example, contention periods and/or timeslots
reserved for a particular CPE. In FIG. 8A, the timeslots 802 occur
at non-independently-determinable intervals. That is, from the
cable modem's perspective, the duration of each of the intervals
.quadrature..quadrature.1, .quadrature.2, and .quadrature.3 is
random and, thus the cable modem has to continuously listen.
Similarly, timeslots 804 occur at non-independently-determinable
intervals. That is, from the cable modem's perspective, the
duration of each of the intervals .quadrature..quadrature.4,
.quadrature.5, and .quadrature.6 is random and, thus the cable
modem has to continuously listen. In FIG. 8B, after the CPE has
been permitted to enter a power-saving mode of operation, the
timeslots 802 and 804 occur at predetermined, fixed intervals. That
is, the cable modem can independently determine the duration of
each of .quadrature.8-.quadrature.13 and power off and on its
receiver accordingly.
[0061] FIG. 9 is a flowchart illustrating exemplary steps for
managing a power-saving state in a client device of a wide area
network. The steps are described with respect to a cable modem, but
may be implemented in other types of devices. The exemplary steps
begin with start step 902 and proceed to step 904. In step 904, the
cable modem connects to the WAN and exchanges messages with the
CMTS to be registered on the network. In step 906, the cable modem
decides to transition to a power-saving state. This decision may be
based, for example, on past traffic patterns and/or statistics,
expected future traffic, time of day, type and/or number of devices
connected to the cable modem, a level of service to which the cable
modem is subscribed, an amount of bandwidth that the cable modem
has used in the billing period or has left to use in the billing
period, or any other suitable considerations.
[0062] In step 908, the cable modem sends a request for permission
to transition to the sleep state. The request may comprise, for
example, a MAC management message wherein the contents of its Type
Value field are uniquely associated with a request to enter a sleep
mode. The message may also comprise various information such as,
for example, how long the cable modem desires to sleep, the traffic
expected by the cable modem, the number and/or types of devices
downstream from the cable modem, the channel(s) on which the cable
modem may receive and/or transmit while in the power-saving mode,
the type of signals that the cable modem may transmit and/or
receive while in the power-saving mode, and/or any other suitable
information.
[0063] In step 910, it is determined whether the CMTS granted the
cable modem's request to enter the power-saving mode of operation.
If such a grant is not received, then the exemplary steps advance
to step 916 and the cable modem does not transition to the
low-power mode. If, on the other hand, the CMTS does grant the
request, then the exemplary steps advance to step 912.
[0064] In step 912, the cable modem may set a sleep timer. The
initial and/or terminal value of the timer may be determined based
on a variety of factors. For example, the timer may be set based on
accuracy (e.g., drift) of one or more clocks in the cable modem,
type and/or number of devices downstream of the cable modem (e.g.,
within the premises served by the cable modem), past traffic
patterns and/or statistics, the timing at which the CMTS has
indicated MAC management messages will be sent, the timing at which
the CMTS has indicated contention periods will, the timing at which
the CMTS has indicated transmit opportunities for the cable modem
will occur, and/or any other suitable factors. The sleep timer may
be set to compensate for an amount of time it takes the cable modem
to transition out of the power-saving state and be ready to
transmit or receive. For example, the sleep timer may be set to
wake the cable modem up and amount of time, X, before the next MAP
message, where X is the transition time it takes the cable modem to
power up circuitry for receiving a MAP message. As another example,
the cable modem may desire to sleep for two MAP cycles and,
therefore, may set its sleep timer to 2Y-X, where Y is the duration
of the interval between MAP messages.
[0065] In step 914, upon expiration of the sleep timer, the cable
modem may transition out of the low-power mode and, in step 916,
return to normal operation.
[0066] FIG. 10 is a flowchart illustrating exemplary steps for
managing a power-saving state in a client device of a wide area
network. The steps are described with respect to a cable modem, but
may be implemented in other types of devices. The exemplary steps
begin with start step 1002 and proceed to step 1004. In step 1004,
the cable modem connects to the WAN and exchanges messages with the
CMTS to be registered on the network. In step 1006, the cable modem
decides to transition to a power-saving state. This decision may be
based, for example, on past traffic patterns and/or statistics,
expected future traffic, time of day, type and/or number of devices
connected to the cable modem, a level of service to which the cable
modem is subscribed, an amount of bandwidth that the cable modem
has used in the billing period or has left to use in the billing
period, or any other suitable considerations.
[0067] In step 1008, the cable modem sends a request for permission
to transition to the sleep state. The request may comprise, for
example, a MAC management message wherein the contents of its Type
Value field are uniquely associated with a request to enter a sleep
mode. The message may also comprise various parameters such as, for
example, how long the cable modem desires to sleep, the traffic
expected by the cable modem, the number and/or types of devices
downstream from the cable modem, the channel(s) on which the cable
modem may receive and/or transmit while in the power-saving mode,
the type of signals that the cable modem may transmit and/or
receive while in the power-saving mode, and/or any other suitable
information.
[0068] In step 1010, the CMTS decides to permit the cable modem to
sleep and, accordingly, transitions to a mode in which it one or
more of the following are true: MAC management messages are sent at
independently determinable (e.g., predetermined) intervals;
contention opportunities occur at independently determinable (e.g.,
predetermined) intervals; timeslots reserved for communications by
the cable modem occur at independently determinable (e.g.,
predetermined) intervals.
[0069] In step 1012, the CMTS sends the sleep grant to the cable
modem. The sleep grant may comprise, for example, a MAC management
message wherein the contents of its Type Value field are uniquely
associated with a grant of permission to enter a sleep mode. The
message may also comprise various information such as, for example,
how long the cable modem is permitted to sleep, the traffic
expected by the CMTS, the channel(s) on which the CMTS may receive
from and/or transmit to the cable modem while the cable modem is in
the power-saving mode, the type of signals that the cable modem
must and/or may transmit and/or receive while in the power-saving
mode, and/or any other suitable information. In step 1014, the
cable modem may transition to the power-saving mode.
[0070] In step 1016, the cable modem may buffer packets for future
processing by the cable modem while it is in the power-saving mode.
For example, portions of the PHY may remain powered-up in the
low-power mode and those portions may be operable to receive
traffic from the WAN and buffer it until other portions of the
cable modem (e.g., the MAC and/or other portions of the PHY)
transition out of the power-saving mode. As another example,
portions of the MAC may remain powered-up in the low-power mode and
those portions may be operable to receive traffic from higher OSI
layers (e.g., traffic generated by the host processor of the cable
modem and/or received from devices in the premises served by the
cable modem) and buffer the traffic until other portions of the
cable modem (e.g., the PHY and/or other portions of the MAC)
transition out of the power-saving mode.
[0071] In step 1018, upon buffer fullness reaching a set threshold,
the cable modem may wake up and process the buffered traffic. For
buffered traffic to be transmitted on the WAN, the transition out
of the low-power mode may be timed such that the cable modem is
ready to transmit the buffered traffic just as the next contention
period or timeslot reserved for the cable modem is about to occur.
The buffer threshold may be set based on, for example, past traffic
patterns and/or statistics, expected future traffic, time of day,
type and/or number of devices connected to the cable modem, a level
of service to which the cable modem is subscribed, an amount of
bandwidth that the cable modem has used in the billing period or
has left to use in the billing period, or any other suitable
considerations.
[0072] Other embodiments of the invention may provide a
non-transitory computer readable medium and/or storage medium,
and/or a non-transitory machine readable medium and/or storage
medium, having stored thereon, a machine code and/or a computer
program having at least one code section executable by a machine
and/or a computer, thereby causing the machine and/or computer to
perform the steps as described herein for a low-power client in a
wide area network.
[0073] Accordingly, the present invention may be realized in
hardware, software, or a combination of hardware and software. The
present invention may be realized in a centralized fashion in at
least one computing system, or in a distributed fashion where
different elements are spread across several interconnected
computing systems. Any kind of computing system or other system
adapted for carrying out the methods described herein is suited. A
typical combination of hardware and software may be a
general-purpose computing system with a program or other code that,
when being loaded and executed, controls the computing system such
that it carries out the methods described herein. Another typical
implementation may comprise an application specific integrated
circuit or chip.
[0074] The present invention may also be embedded in a computer
program product, which comprises all the features enabling the
implementation of the methods described herein, and which when
loaded in a computer system is able to carry out these methods.
Computer program in the present context means any expression, in
any language, code or notation, of a set of instructions intended
to cause a system having an information processing capability to
perform a particular function either directly or after either or
both of the following: a) conversion to another language, code or
notation; b) reproduction in a different material form.
[0075] While the present invention has been described with
reference to certain embodiments, it will be understood by those
skilled in the art that various changes may be made and equivalents
may be substituted without departing from the scope of the present
invention. In addition, many modifications may be made to adapt a
particular situation or material to the teachings of the present
invention without departing from its scope. Therefore, it is
intended that the present invention not be limited to the
particular embodiment disclosed, but that the present invention
will include all embodiments falling within the scope of the
appended claims.
* * * * *