U.S. patent application number 15/646664 was filed with the patent office on 2017-10-26 for ultra low-power paging frames for wake-up and discovery.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Santosh Paul ABRAHAM, Alfred ASTERJADHI, Rahul MALIK, Simone MERLIN, Stephen Jay SHELLHAMMER.
Application Number | 20170311149 15/646664 |
Document ID | / |
Family ID | 55349492 |
Filed Date | 2017-10-26 |
United States Patent
Application |
20170311149 |
Kind Code |
A1 |
SHELLHAMMER; Stephen Jay ;
et al. |
October 26, 2017 |
ULTRA LOW-POWER PAGING FRAMES FOR WAKE-UP AND DISCOVERY
Abstract
Certain aspects of the present disclosure generally relate to
wireless communications and, more particularly, to ultra low-power
paging frames for wake up and discovery. One example apparatus for
wireless communications generally includes at least one interface
configured to receive via a first radio and a second radio, wherein
the at least one interface receives a paging frame from another
apparatus via the second radio while the first radio is in a first
power state that is lower than a second power state of the second
radio; and a processing system configured to take one or more
actions based on a command field included in the paging frame.
Inventors: |
SHELLHAMMER; Stephen Jay;
(Ramona, CA) ; ABRAHAM; Santosh Paul; (San Diego,
CA) ; MERLIN; Simone; (San Diego, CA) ; MALIK;
Rahul; (San Diego, CA) ; ASTERJADHI; Alfred;
(San Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
55349492 |
Appl. No.: |
15/646664 |
Filed: |
July 11, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14827020 |
Aug 14, 2015 |
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15646664 |
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62039482 |
Aug 20, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 12/1008 20190101;
H04W 76/14 20180201; H04W 68/02 20130101; H04W 52/0209 20130101;
H04W 76/27 20180201; H04W 52/0219 20130101; H04W 84/12 20130101;
H04W 68/005 20130101; H04L 63/123 20130101; H04W 8/005 20130101;
H04W 56/00 20130101; H04W 88/06 20130101; H04W 52/0216 20130101;
H04W 56/001 20130101; H04W 52/0225 20130101; H04W 12/1006 20190101;
Y02D 70/164 20180101; Y02D 70/142 20180101; Y02D 30/70 20200801;
H04W 52/0229 20130101 |
International
Class: |
H04W 8/00 20090101
H04W008/00; H04W 12/04 20090101 H04W012/04; H04W 12/06 20090101
H04W012/06; H04W 12/10 20090101 H04W012/10; H04W 52/02 20090101
H04W052/02; H04W 52/02 20090101 H04W052/02; H04W 68/02 20090101
H04W068/02; H04W 68/00 20090101 H04W068/00; H04W 52/02 20090101
H04W052/02; H04W 52/02 20090101 H04W052/02 |
Claims
1-18. (canceled)
19. An apparatus for wireless communications, comprising: a
processing system configured to: determine whether another
apparatus is capable of receiving a paging frame, via a second
radio, while a first radio of the other apparatus is in a sleep
mode; and based on the determination, generate a paging frame
comprising a command field that indicates one or more actions for
the other apparatus to take; and at least one interface configured
to output the paging frame for transmission to the other
apparatus.
20. The apparatus of claim 19, wherein: the paging frame further
comprises a medium access control (MAC) header having a frame
control field with a subfield set to a value that indicates a type
of the paging frame.
21. The apparatus of claim 19, wherein the paging frame further
comprises at least one of: a control frame, a management frame, or
a data frame.
22. The apparatus of claim 19, wherein: the paging frame further
comprises a medium access control (MAC) header having a frame check
sequence (FCS) field having a shorter length than FCS fields of
other types of frames.
23. The apparatus of claim 19, wherein: the paging frame further
comprises a medium access control (MAC) header that lacks at least
one of a receiver address (RA) or a transmitter address (TA).
24. The apparatus of claim 19, wherein: the paging frame further
comprises a medium access control (MAC) header having a
network-wide identifier (NWID) field set to a value that identifies
a network to which the apparatus is associated.
25. The apparatus of claim 24, wherein the NWID field comprises one
of: a station identifier (SID), a service set identifier (SSID), a
hashed version of an SID, or a hashed version of an SSID.
26. The apparatus of claim 19, wherein: the at least one interface
is further configured to receive, as part of a capability exchange,
capability information from the other apparatus indicating the
other apparatus is capable of receiving low-power paging frames;
and the processing system is further configured to determine the
other apparatus is capable of receiving the paging frame, via the
second radio, while the first radio of the other apparatus is in
sleep mode based on the capability information.
27. The apparatus of claim 19, wherein: the one or more actions
comprise at least one of causing the first radio to exit the sleep
mode or adjusting a local clock of the other apparatus.
28. The apparatus of claim 27, wherein the local clock of the other
apparatus is adjusted based on a clock value of a field in the
paging frame.
29. The apparatus of claim 28, wherein: the clock value comprises
least significant bits (LSBs) of a value of a clock associated with
the apparatus.
30. The apparatus of claim 27, wherein: the command field further
indicates the apparatus is capable of Wi-Fi Direct; and the one or
more actions comprise causing the first radio to exit the sleep
mode, so the other apparatus can communicate with the apparatus via
Wi-Fi Direct.
31. The apparatus of claim 30, wherein: the one or more actions
further comprise notifying the first radio, via the second radio,
the apparatus is capable of Wi-Fi Direct.
32. The apparatus of claim 19, wherein: the command field further
indicates the apparatus is associated with a social group; the
processing system is configured to provide, via a medium access
control (MAC) header of the paging frame, an indication of a time
offset, relative to a transmission time of the paging frame,
corresponding to a window during which frames are sent by one or
more members of the social group for discovery; and the one or more
actions comprise causing the first radio to exit the sleep mode
during the window.
33. The apparatus of claim 27, wherein: the paging frame comprises
a medium access control (MAC) header having a field with
association assist information; and the one or more actions
comprise causing the first radio to exit the sleep mode to attempt
association with the apparatus using the association assist
information.
34. The apparatus of claim 33, wherein: the association assist
information comprises a service set ID (SSID) of the apparatus; and
the one or more actions comprises associating with the apparatus if
the SSID of the apparatus is in a list of relevant SSIDs stored at
the other apparatus.
35-52. (canceled)
53. A method for wireless communications by an apparatus,
comprising: determining whether another apparatus is capable of
receiving a paging frame, via a second radio, while a first radio
of the other apparatus is in a sleep mode; and based on the
determination, generating a paging frame comprising a command field
that indicates one or more actions for the other apparatus to take;
and outputting the paging frame for transmission to the other
apparatus.
54. The method of claim 53, wherein: the paging frame further
comprises a medium access control (MAC) header having a frame
control field with a subfield set to a value that indicates a type
of the paging frame.
55. The method of claim 53, wherein the paging frame further
comprises at least one of: a control frame, a management frame, or
a data frame.
56-105. (canceled)
106. An access point, comprising: a processing system configured
to: determine whether an apparatus is capable of receiving a paging
frame, via a second radio, while a first radio of the apparatus is
in a sleep mode; and based on the determination, generate a paging
frame comprising a command field that indicates one or more actions
for the apparatus to take; and a transmitter configured to transmit
the paging frame to the apparatus.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a divisional application of U.S. patent
application Ser. No. 14/827,020 entitled "ULTRA LOW-POWER PAGING
FRAMES FOR WAKE-UP AND DISCOVERY", filed Aug. 14, 2015, which
claims benefit of U.S. Provisional Patent Application Ser. No.
62/039,482, filed Aug. 20, 2014, both of which are herein
incorporated by reference in their entirety.
BACKGROUND
Field of the Disclosure
[0002] Certain aspects of the present disclosure generally relate
to wireless communications and, more specifically, to ultra
low-power paging frames (e.g., short medium access control (MAC)
frames) for wake-up and discovery.
Description of Related Art
[0003] Wireless communication networks are widely deployed to
provide various communication services such as voice, video, packet
data, messaging, broadcast, etc. These wireless networks may be
multiple-access networks capable of supporting multiple users by
sharing the available network resources. Examples of such
multiple-access networks include Code Division Multiple Access
(CDMA) networks, Time Division Multiple Access (TDMA) networks,
Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA
(OFDMA) networks, and Single-Carrier FDMA (SC-FDMA) networks.
[0004] In order to address the desire for greater coverage and
increased communication range, various schemes are being developed.
One such scheme is the sub-1-GHz frequency range (e.g., operating
in the 902-928 MHz range in the United States) being developed by
the Institute of Electrical and Electronics Engineers (IEEE)
802.11ah task force. This development is driven by the desire to
utilize a frequency range that has greater wireless range than
wireless ranges associated with frequency ranges of other IEEE
802.11 technologies and potentially fewer issues associated with
path losses due to obstructions.
SUMMARY
[0005] The systems, methods, and devices of the disclosure each
have several aspects, no single one of which is solely responsible
for its desirable attributes. Without limiting the scope of this
disclosure as expressed by the claims which follow, some features
will now be discussed briefly. After considering this discussion,
and particularly after reading the section entitled "Detailed
Description" one will understand how the features of this
disclosure provide advantages that include improved communications
between access points and stations in a wireless network.
[0006] Certain aspects of the present disclosure provide for ultra
low-power paging frames (e.g., short medium access control (MAC)
frames) for wake-up and discovery.
[0007] Certain aspects of the present disclosure provide an
apparatus for wireless communications. The apparatus generally
includes at least one interface configured to receive via a first
radio and a second radio, wherein the at least one interface
receives a paging frame from another apparatus via the second radio
while the first radio is in a first power state that is lower than
a second power state of the second radio; and a processing system
configured to take one or more actions based on a command field
included in the paging frame.
[0008] Certain aspects of the present disclosure provide an
apparatus for wireless communications. The apparatus generally
includes a processing system configured to determine whether
another apparatus is capable of receiving a paging frame, via a
second radio of the other apparatus, while a first radio is in a
first power state that is lower than a second power state of the
second radio and based on the determination, generate a paging
frame comprising a command field that indicates one or more actions
for the other apparatus to take; and at least one interface
configured to output the paging frame for transmission to the other
apparatus.
[0009] Certain aspects of the present disclosure provide a method
for wireless communications by a user equipment (UE). The method
generally includes receiving a paging frame from an apparatus via a
second radio while a first radio is in a first power state that is
lower than a second power state of the second radio and taking one
or more actions based on a command field included in the paging
frame.
[0010] Certain aspects of the present disclosure provide a method
for wireless communications by an apparatus. The method generally
includes determining whether another apparatus is capable of
receiving a paging frame, via a second radio of the other
apparatus, while a first radio is in a first power state that is
lower than a second power state of the second radio, based on the
determination, generating a paging frame comprising a command field
that indicates one or more actions for the other apparatus to take,
and outputting the paging frame for transmission to the other
apparatus.
[0011] Certain aspects of the present disclosure provide an
apparatus for wireless communications. The apparatus generally
includes means for receiving a paging frame from another apparatus
via a second radio while a first radio is in a first power state
that is lower than a second power state of the second radio and
means for taking one or more actions based on a command field
included in the paging frame.
[0012] Certain aspects of the present disclosure provide an
apparatus for wireless communications. The apparatus generally
includes means for determining whether another apparatus is capable
of receiving a paging frame, via a second radio of the other
apparatus, while a first radio is in a first power state that is
lower than a second power state of the second radio, means for
generating, based on the determination, a paging frame comprising a
command field that indicates one or more actions for the other
apparatus to take, and means for outputting the paging frame for
transmission to the other apparatus.
[0013] Certain aspects of the present disclosure provide a computer
readable medium. The computer readable medium generally includes
computer executable code stored thereon for: receiving a paging
frame from an apparatus via a second radio while a first radio is
in a first power state that is lower than a second power state of
the second radio, and taking one or more actions based on a command
field included in the paging frame.
[0014] Certain aspects of the present disclosure provide a computer
readable medium. The computer readable medium generally includes
computer executable code stored thereon for: determining whether an
apparatus is capable of receiving a paging frame, via a second
radio of the other apparatus, while a first radio is in a first
power state that is lower than a second power state of the second
radio; based on the determination, generating a paging frame
comprising a command field that indicates one or more actions for
the apparatus to take, and outputting the paging frame for
transmission to the apparatus.
[0015] Certain aspects of the present disclosure provide an access
terminal. The access terminal generally includes a first radio, a
second radio configured to receive a paging frame from an apparatus
while the first radio is in a first power state that is lower than
a second power state of the second radio, and a processing system
configured to take one or more actions based on a command field
included in the paging frame.
[0016] Certain aspects of the present disclosure provide an access
point. The access point generally includes at least one antenna and
a processing system configured to: determine whether an apparatus
is capable of receiving a paging frame, via a second radio of the
other apparatus, while a first radio is in a first power state that
is lower than a second power state of the second radio; based on
the determination, generate a paging frame comprising a command
field that indicates one or more actions for the apparatus to take;
and transmit the paging frame, via the at least one antenna, to the
apparatus.
[0017] To the accomplishment of the foregoing and related ends, the
one or more aspects comprise the features hereinafter fully
described and particularly pointed out in the claims. The following
description and the annexed drawings set forth in detail certain
illustrative features of the one or more aspects. These features
are indicative, however, of but a few of the various ways in which
the principles of various aspects may be employed, and this
description is intended to include all such aspects and their
equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 illustrates a diagram of an example wireless
communications network, in accordance with certain aspects of the
present disclosure.
[0019] FIG. 2 illustrates a block diagram of an example access
point (AP) and user terminals (UTs), in accordance with certain
aspects of the present disclosure.
[0020] FIG. 3 illustrates a block diagram of an example wireless
device, in accordance with certain aspects of the present
disclosure.
[0021] FIG. 4 illustrates an example short frame format, according
to certain aspects of the present disclosure.
[0022] FIG. 4A illustrates an example short control frame format,
according to certain aspects of the present disclosure.
[0023] FIG. 5 illustrates subfields of the FC field 402, in
accordance with certain aspects of the present disclosure.
[0024] FIG. 6 illustrates a block diagram of an example ultra-low
power transmitter as a companion radio to a primary AP radio in
communication with an ultra-low power receiver as a companion to a
primary Internet-of-Things (IoT) device radio, in accordance with
certain aspects of the present disclosure.
[0025] FIG. 7 illustrates an example short control frame format for
ultra-low power paging, in accordance with certain aspects of the
present disclosure.
[0026] FIG. 7A illustrates an example short control frame format
for ultra-low power paging that lacks address fields, sequence
control field, and frame body field, in accordance with certain
aspects of the present disclosure.
[0027] FIG. 7B illustrates an example short control frame format
for ultra-low power paging, in accordance with certain aspects of
the present disclosure.
[0028] FIGS. 8-8A illustrate example subfields of the FC field of a
short control frame for ultra-low power paging, in accordance with
certain aspects of the present disclosure.
[0029] FIGS. 9-11 illustrate example ultra-low power paging frames
for primary radio wake-up, in accordance with certain aspects of
the present disclosure.
[0030] FIGS. 12-13 illustrate example ultra-low power paging frames
for clock resynchronization, in accordance with certain aspects of
the present disclosure.
[0031] FIGS. 14-14A illustrate example ultra-low power paging
frames for Wi-Fi Direct Discovery Assist, in accordance with
certain aspects of the present disclosure.
[0032] FIG. 15-15A illustrate example ultra low-power paging frames
for Social Wi-Fi Discovery Assist, in accordance with certain
aspects of the present disclosure.
[0033] FIG. 16 illustrates an example ultra low-power paging frame
1500 for Association Assist, in accordance with certain aspects of
the present disclosure.
[0034] FIG. 17 illustrates example operations for wireless
communications, in accordance with certain aspects of the present
disclosure.
[0035] FIG. 17A illustrates example means capable of performing the
operations shown in FIG. 17.
[0036] FIG. 18 illustrates example operations for wireless
communications, in accordance with certain aspects of the present
disclosure.
[0037] FIG. 18A illustrates example means capable of performing the
operations shown in FIG. 18.
[0038] To facilitate understanding, identical reference numerals
have been used, where possible, to designate identical elements
that are common to the figures. It is contemplated that elements
disclosed in one embodiment may be beneficially utilized on other
embodiments without specific recitation.
DETAILED DESCRIPTION
[0039] Various aspects of the disclosure are described more fully
hereinafter with reference to the accompanying drawings. This
disclosure may, however, be embodied in many different forms and
should not be construed as limited to any specific structure or
function presented throughout this disclosure. Rather, these
aspects are provided so that this disclosure will be thorough and
complete, and will fully convey the scope of the disclosure to
those skilled in the art. Based on the teachings herein one skilled
in the art should appreciate that the scope of the disclosure is
intended to cover any aspect of the disclosure disclosed herein,
whether implemented independently of or combined with any other
aspect of the disclosure. For example, an apparatus may be
implemented or a method may be practiced using any number of the
aspects set forth herein. In addition, the scope of the disclosure
is intended to cover such an apparatus or method which is practiced
using other structure, functionality, or structure and
functionality in addition to or other than the various aspects of
the disclosure set forth herein. It should be understood that any
aspect of the disclosure disclosed herein may be embodied by one or
more elements of a claim.
[0040] Techniques and apparatus are provided herein for ultra
low-power paging frames (e.g., short medium access control (MAC)
frames) for wake-up and discovery. In aspects, techniques are
provided for determining whether another apparatus is capable of
receiving a paging frame (e.g., an ultra low-power paging frame),
via a second radio (e.g., a companion radio), while a first radio
(e.g., a primary radio) is in a low-power state and to generate and
transmit, to the other apparatus, a paging frame comprising a
command field (e.g., a message ID field) that indicates one or more
actions for the other apparatus to take.
[0041] The word "exemplary" is used herein to mean "serving as an
example, instance, or illustration." Any aspect described herein as
"exemplary" is not necessarily to be construed as preferred or
advantageous over other aspects.
[0042] Although particular aspects are described herein, many
variations and permutations of these aspects fall within the scope
of the disclosure. Although some benefits and advantages of the
preferred aspects are mentioned, the scope of the disclosure is not
intended to be limited to particular benefits, uses, or objectives.
Rather, aspects of the disclosure are intended to be broadly
applicable to different wireless technologies, system
configurations, networks, and transmission protocols, some of which
are illustrated by way of example in the figures and in the
following description of the preferred aspects. The detailed
description and drawings are merely illustrative of the disclosure
rather than limiting, the scope of the disclosure being defined by
the appended claims and equivalents thereof.
An Example Wireless Communication System
[0043] The techniques described herein may be used for various
broadband wireless communication systems, including communication
systems that are based on an orthogonal multiplexing scheme.
Examples of such communication systems include Spatial Division
Multiple Access (SDMA), Time Division Multiple Access (TDMA),
Orthogonal Frequency Division Multiple Access (OFDMA) systems,
Single-Carrier Frequency Division Multiple Access (SC-FDMA)
systems, and so forth. An SDMA system may use sufficiently
different directions to simultaneously transmit data belonging to
multiple user terminals. A TDMA system may allow multiple user
terminals to share the same frequency channel by dividing the
transmission signal into different time slots, each time slot being
assigned to different user terminal. An OFDMA system uses
orthogonal frequency division multiplexing (OFDM), which is a
modulation technique that partitions the overall system bandwidth
into multiple orthogonal sub-carriers. These sub-carriers may also
be called tones, bins, etc. With OFDM, each sub-carrier may be
independently modulated with data. An SC-FDMA system may use
interleaved FDMA (IFDMA) to transmit on sub-carriers that are
distributed across the system bandwidth, localized FDMA (LFDMA) to
transmit on a block of adjacent sub-carriers, or enhanced FDMA
(EFDMA) to transmit on multiple blocks of adjacent sub-carriers. In
general, modulation symbols are sent in the frequency domain with
OFDM and in the time domain with SC-FDMA.
[0044] The teachings herein may be incorporated into (e.g.,
implemented within or performed by) a variety of wired or wireless
apparatuses (e.g., nodes). In some aspects, a wireless node
implemented in accordance with the teachings herein may comprise an
access point or an access terminal.
[0045] An access point ("AP") may comprise, be implemented as, or
known as a Node B, a Radio Network Controller ("RNC"), an evolved
Node B (eNB), a Base Station Controller ("BSC"), a Base Transceiver
Station ("BTS"), a Base Station ("BS"), a Transceiver Function
("TF"), a Radio Router, a Radio Transceiver, a Basic Service Set
("BSS"), an Extended Service Set ("ESS"), a Radio Base Station
("RBS"), or some other terminology.
[0046] An access terminal ("AT") may comprise, be implemented as,
or known as a subscriber station, a subscriber unit, a mobile
station, a remote station, a remote terminal, a user terminal, a
user agent, a user device, user equipment, a user station, or some
other terminology. In some implementations, an access terminal may
comprise a cellular telephone, a cordless telephone, a Session
Initiation Protocol ("SIP") phone, a wireless local loop ("WLL")
station, a personal digital assistant ("PDA"), a handheld device
having wireless connection capability, a Station ("STA"), or some
other suitable processing device connected to a wireless modem.
Accordingly, one or more aspects taught herein may be incorporated
into a phone (e.g., a cellular phone or smart phone), a computer
(e.g., a laptop), a portable communication device, a portable
computing device (e.g., a personal data assistant), an
entertainment device (e.g., a music or video device, or a satellite
radio), a global positioning system device, or any other suitable
device that is configured to communicate via a wireless or wired
medium.
[0047] FIG. 1 illustrates a system 100 in which aspects of the
disclosure may be performed. For example, the access point 110 or
user terminal 120 may determine whether another access point 110 or
user terminal 120 is capable of receiving a paging frame (e.g., an
ultra low-power paging frame) via a second radio (e.g., a companion
radio), while a first radio (e.g., a primary radio) is in a
low-power state. The access point 110 or user terminal 120 may
generate and transmit the paging frame comprising a command field
(e.g., a message ID field) that indicates one or more actions for
the other access point 110 or user terminal 120 to take.
[0048] The system 100 may be, for example, a multiple-access
multiple-input multiple-output (MIMO) system 100 with access points
and user terminals. For simplicity, only one access point 110 is
shown in FIG. 1. An access point is generally a fixed station that
communicates with the user terminals and may also be referred to as
a base station or some other terminology. A user terminal may be
fixed or mobile and may also be referred to as a mobile station, a
wireless device or some other terminology. Access point 110 may
communicate with one or more user terminals 120 at any given moment
on the downlink and uplink. The downlink (i.e., forward link) is
the communication link from the access point to the user terminals,
and the uplink (i.e., reverse link) is the communication link from
the user terminals to the access point. A user terminal may also
communicate peer-to-peer with another user terminal. A system
controller 130 may couple to and provide coordination and control
for the access point.
[0049] A system controller 130 may provide coordination and control
for these APs and/or other systems. The APs may be managed by the
system controller 130, for example, which may handle adjustments to
radio frequency power, channels, authentication, and security. The
system controller 130 may communicate with the APs via a backhaul.
The APs may also communicate with one another, e.g., directly or
indirectly via a wireless or wireline backhaul.
[0050] While portions of the following disclosure will describe
user terminals 120 capable of communicating via Spatial Division
Multiple Access (SDMA), for certain aspects, the user terminals 120
may also include some user terminals that do not support SDMA.
Thus, for such aspects, an access point (AP) 110 may be configured
to communicate with both SDMA and non-SDMA user terminals. This
approach may conveniently allow older versions of user terminals
("legacy" stations) to remain deployed in an enterprise, extending
their useful lifetime, while allowing newer SDMA user terminals to
be introduced as deemed appropriate.
[0051] The access point 110 and user terminals 120 employ multiple
transmit and multiple receive antennas for data transmission on the
downlink and uplink. For downlink MIMO transmissions, N.sub.ap
antennas of the access point 110 represent the multiple-input (MI)
portion of MIMO, while a set of K user terminals represent the
multiple-output (MO) portion of MIMO. Conversely, for uplink MIMO
transmissions, the set of K user terminals represent the MI
portion, while the N.sub.ap antennas of the access point 110
represent the MO portion. For pure SDMA, it is desired to have
N.sub.ap.gtoreq.K.gtoreq.1 if the data symbol streams for the K
user terminals are not multiplexed in code, frequency or time by
some means. K may be greater than N.sub.ap if the data symbol
streams can be multiplexed using TDMA technique, different code
channels with CDMA, disjoint sets of subbands with OFDM, and so on.
Each selected user terminal transmits user-specific data to and/or
receives user-specific data from the access point. In general, each
selected user terminal may be equipped with one or multiple
antennas (i.e., N.sub.ut.gtoreq.1). The K selected user terminals
can have the same or different number of antennas.
[0052] The system 100 may be a time division duplex (TDD) system or
a frequency division duplex (FDD) system. For a TDD system, the
downlink and uplink share the same frequency band. For an FDD
system, the downlink and uplink use different frequency bands. MIMO
system 100 may also use a single carrier or multiple carriers for
transmission. Each user terminal may be equipped with a single
antenna (e.g., in order to keep costs down) or multiple antennas
(e.g., where the additional cost can be supported). The system 100
may also be a TDMA system if the user terminals 120 share the same
frequency channel by dividing transmission/reception into different
time slots, each time slot being assigned to different user
terminal 120.
[0053] FIG. 2 illustrates example components of the AP 110 and UT
120 illustrated in FIG. 1, which may be used to implement aspects
of the present disclosure. One or more components of the AP 110 and
UT 120 may be used to practice aspects of the present disclosure.
For example, antenna 224, Tx/Rx 222, processors 210, 220, 240, 242,
and/or controller 230 may be used to perform the operations
described herein and illustrated with reference to FIGS. 17-18A.
Similarly, antenna 252, Tx/Rx 254, processors 260, 270, 288, and
290, and/or controller 280 of the UT 120 may be used to perform the
operations described herein and illustrated with reference to FIGS.
17-18A.
[0054] FIG. 2 illustrates a block diagram of access point 110 and
two user terminals 120m and 120x in MIMO system 100. The access
point 110 is equipped with N.sub.t antennas 224a through 224ap.
User terminal 120m is equipped with N.sub.ut,m antennas 252ma
through 252mu, and user terminal 120x is equipped with N.sub.ut,x
antennas 252xa through 252xu. The access point 110 is a
transmitting entity for the downlink and a receiving entity for the
uplink. Each user terminal 120 is a transmitting entity for the
uplink and a receiving entity for the downlink. As used herein, a
"transmitting entity" is an independently operated apparatus or
device capable of transmitting data via a wireless channel, and a
"receiving entity" is an independently operated apparatus or device
capable of receiving data via a wireless channel. In the following
description, the subscript "dn" denotes the downlink, the subscript
"up" denotes the uplink. For SDMA transmissions, N.sub.np user
terminals simultaneously transmit on the uplink, while N.sub.dn
user terminals simultaneously transmit on the downlink. N.sub.np
may or may not be equal to N.sub.dn, and N.sub.np and N.sub.dn may
be static values or can change for each scheduling interval. The
beam-steering or some other spatial processing technique may be
used at the access point and user terminal.
[0055] On the uplink, at each user terminal 120 selected for uplink
transmission, a transmit (TX) data processor 288 receives traffic
data from a data source 286 and control data from a controller 280.
The controller 280 may be coupled with a memory 282. TX data
processor 288 processes (e.g., encodes, interleaves, and modulates)
the traffic data for the user terminal based on the coding and
modulation schemes associated with the rate selected for the user
terminal and provides a data symbol stream. A TX spatial processor
290 performs spatial processing on the data symbol stream and
provides N.sub.ut,m transmit symbol streams for the N.sub.ut,m
antennas. Each transmitter unit (TMTR) 254 receives and processes
(e.g., converts to analog, amplifies, filters, and frequency
upconverts) a respective transmit symbol stream to generate an
uplink signal. N.sub.ut,m transmitter units 254 provide N.sub.ut,m
uplink signals for transmission from N.sub.ut,m antennas 252 to the
access point.
[0056] N.sub.up user terminals may be scheduled for simultaneous
transmission on the uplink. Each of these user terminals performs
spatial processing on its data symbol stream and transmits its set
of transmit symbol streams on the uplink to the access point.
[0057] At access point 110, N.sub.ap antennas 224a through 224ap
receive the uplink signals from all N.sub.up user terminals
transmitting on the uplink. Each antenna 224 provides a received
signal to a respective receiver unit (RCVR) 222. Each receiver unit
222 performs processing complementary to that performed by
transmitter unit 254 and provides a received symbol stream. An RX
spatial processor 240 performs receiver spatial processing on the
N.sub.ap received symbol streams from N.sub.ap receiver units 222
and provides N.sub.up recovered uplink data symbol streams. The
receiver spatial processing is performed in accordance with the
channel correlation matrix inversion (CCMI), minimum mean square
error (MMSE), soft interference cancellation (SIC), or some other
technique. Each recovered uplink data symbol stream is an estimate
of a data symbol stream transmitted by a respective user terminal.
An RX data processor 242 processes (e.g., demodulates,
deinterleaves, and decodes) each recovered uplink data symbol
stream in accordance with the rate used for that stream to obtain
decoded data. The decoded data for each user terminal may be
provided to a data sink 244 for storage and/or a controller 230 for
further processing. The controller 230 may be coupled with a memory
232.
[0058] On the downlink, at access point 110, a TX data processor
210 receives traffic data from a data source 208 for N.sub.dn user
terminals scheduled for downlink transmission, control data from a
controller 230, and possibly other data from a scheduler 234. The
various types of data may be sent on different transport channels.
TX data processor 210 processes (e.g., encodes, interleaves, and
modulates) the traffic data for each user terminal based on the
rate selected for that user terminal. TX data processor 210
provides N.sub.dn downlink data symbol streams for the N.sub.dn
user terminals. A TX spatial processor 220 performs spatial
processing (such as a precoding or beamforming, as described in the
present disclosure) on the N.sub.dn downlink data symbol streams,
and provides N.sub.ap transmit symbol streams for the N.sub.ap
antennas. Each transmitter unit 222 receives and processes a
respective transmit symbol stream to generate a downlink signal.
N.sub.ap transmitter units 222 providing N.sub.ap downlink signals
for transmission from N.sub.ap antennas 224 to the user
terminals.
[0059] At each user terminal 120, N.sub.ut,m antennas 252 receive
the N.sub.ap downlink signals from access point 110. Each receiver
unit 254 processes a received signal from an associated antenna 252
and provides a received symbol stream. An RX spatial processor 260
performs receiver spatial processing on N.sub.ut,m received symbol
streams from N.sub.ut,m receiver units 254 and provides a recovered
downlink data symbol stream for the user terminal. The receiver
spatial processing is performed in accordance with the CCMI, MMSE
or some other technique. An RX data processor 270 processes (e.g.,
demodulates, deinterleaves and decodes) the recovered downlink data
symbol stream to obtain decoded data for the user terminal. The
decoded data for each user terminal may be provided to a data sink
272 for storage and/or a controller 280 for further processing.
[0060] At each user terminal 120, a channel estimator 278 estimates
the downlink channel response and provides downlink channel
estimates, which may include channel gain estimates, SNR estimates,
noise variance and so on. Similarly, at access point 110, a channel
estimator 228 estimates the uplink channel response and provides
uplink channel estimates. Controller 280 for each user terminal
typically derives the spatial filter matrix for the user terminal
based on the downlink channel response matrix Hdn,m for that user
terminal. Controller 230 derives the spatial filter matrix for the
access point based on the effective uplink channel response matrix
Hup,eff. Controller 280 for each user terminal may send feedback
information (e.g., the downlink and/or uplink eigenvectors,
eigenvalues, SNR estimates, and so on) to the access point.
Controllers 230 and 280 also control the operation of various
processing units at access point 110 and user terminal 120,
respectively.
[0061] FIG. 3 illustrates example components that may be utilized
in the AP 110 and/or UT 120 to implement aspects of the present
disclosure. For example, the transmitter 310, antenna(s) 316,
processor 304 and/or the DSP 320 may be used to practice aspects of
the present disclosure implemented by the AP. Further, the receiver
312, antenna(s) 316, processor 304 and/or the DSP 320 may be used
to practice aspects of the present disclosure implemented by the
UT.
[0062] The wireless device 302 may include a processor 304 which
controls operation of the wireless device 302. The processor 304
may also be referred to as a central processing unit (CPU). Memory
306, which may include both read-only memory (ROM) and random
access memory (RAM), provides instructions and data to the
processor 304. A portion of the memory 306 may also include
non-volatile random access memory (NVRAM). The processor 304
typically performs logical and arithmetic operations based on
program instructions stored within the memory 306. The instructions
in the memory 306 may be executable to implement the methods
described herein.
[0063] The wireless device 302 may also include a housing 308 that
may include a transmitter 310 and a receiver 312 to allow
transmission and reception of data between the wireless device 302
and a remote node. The transmitter 310 and receiver 312 may be
combined into a transceiver 314. A single or a plurality of
transmit antennas 316 may be attached to the housing 308 and
electrically coupled to the transceiver 314. The wireless device
302 may also include (not shown) multiple transmitters, multiple
receivers, and multiple transceivers.
[0064] The wireless device 302 may also include a signal detector
318 that may be used in an effort to detect and quantify the level
of signals received by the transceiver 314. The signal detector 318
may detect such signals as total energy, energy per subcarrier per
symbol, power spectral density and other signals. The wireless
device 302 may also include a digital signal processor (DSP) 320
for use in processing signals.
[0065] The various components of the wireless device 302 may be
coupled together by a bus system 322, which may include a power
bus, a control signal bus, and a status signal bus in addition to a
data bus.
Example Short Control Frames
[0066] In certain systems (e.g., IEEE 802.11ah systems), a short
frame may be a medium access control (MAC) protocol data unit
(MPDU) having a protocol version field in a frame control field
(FCF) set to 1.
[0067] FIG. 4 illustrates an example short frame format 400,
according to certain aspects of the present disclosure. As shown in
FIG. 4, the short frame format 400 may include a 2-byte Frame
Control (FC) field 402, a 2-byte or 6-byte first Address field (A1)
404, a 2-byte or 6-byte second Address field (A2) 406, a 0-byte
(e.g., not included) or 2-byte Sequence Control (SC) field 408, a
0-byte or 6-byte third Address (A3) field 410, a 0-byte or 6-byte
fourth Address field (A4) 412, a variable length Frame Body field
414, and a 4-byte Frame Check Sequence (FCS) field 416.
[0068] For short control frames, the A1 field 404 and A2 field 406
may be present; however, the SC field 408, A3 field 410, and A4
field 412 may not be present (e.g., 0 bits) in the short frame
format 400, as shown in FIG. 4A, for example.
[0069] FIG. 5 illustrates subfields of the 16-bit (2-byte) FC field
402 or a PV1 short control frame, in accordance with certain
aspects of the present disclosure. As shown in FIG. 5, the FC field
402 may include a 2-bit Protocol Version (PV) subfield 502 set to 1
for short control frames. The FC field 402 may further include a
3-bit Type subfield 504 indicating Control type, a 3-bit
PTID/Subtype subfield 506, a 3-bit Bandwidth Indication subfield
508, a 1-bit Dynamic Indication subfield 510, a 1-bit Next TWT Info
Present subfield 512, a 1-bit More Data subfield 514, a 1-bit Flow
Control subfield 516, a Reserved bit 518.
Example Ultra-Low Power Paging
[0070] Ultra-low power PHY enables an ultra-low power
super-regenerative receiver (e.g., a receiver which consumes less
than 200 .mu.A on a 3 volt battery) and, thus, enables a number of
ultra-low power use cases--some of which are discussed in more
detail below. Additionally, ultra-low power paging frames may be
defined for use with each of the ultra-low power use cases. The use
cases may include, but are not limited to, primary radio wake-up,
Wi-Fi Direct Discovery Assist, Social Wi-Fi Discovery Assist, and
Association Assist.
[0071] According to certain aspects, the receivers/transmitters
used for the ultra-low power use cases described herein may be a
standalone radio, or may operate as a companion radio to a primary
radio (e.g., a Wi-Fi radio) as shown in FIG. 6. In one example,
illustrated in FIG. 6, an ultra-low power transmitter 604 may be
used as a companion radio to the primary wireless access point
radio 602. The ultra-low power transmitter 604 may communicate--in
this example, for wakeup--with ultra-low power receiver 608, which
may be a companion radio to primary wireless Internet-of Things
(JOT) device 606. In one example non-limiting implementation, the
ultra-low power paging frame companion radio may operate in sub-1
GHz (S1G) bands (e.g., as described in IEEE 802.11ah) or in the 2.4
GHz band (e.g., as described in IEEE 802.11n). According to certain
aspects, the ultra-low power receiver may provide long, but the PHY
data rate for ultra-low power paging may be 31.25 kb/s. According
to certain aspects, the MAC frames defined for ultra-low power
paging may be based, for example, on short control and/or
management frames (e.g., using Protocol Version 1), for example, as
illustrated in FIGS. 4, 4A, and 5 above.
[0072] According to certain aspects, ultra-low power paging may
decrease power consumption and increase battery life in each of the
use cases described herein.
Example Ultra Low-Power Paging Frames
[0073] FIG. 7 illustrates an example short control frame format 700
for ultra-low power paging, in accordance with certain aspects of
the present disclosure. According to certain aspects, the frame can
also be a management frame. As shown in FIG. 7, the short control
frame format 700 may include a 2-byte frame control field 702. The
receiver address field (A1) 704 and transmitter address field (A2)
706 may not be needed, thus, the short control frame format 700 may
include 0-, 2-, or 6-byte A1 and A2 fields. The short control frame
format 700 may include the 0- or 2-byte Sequence Control field 408,
the 0- or 6-byte A3 field 410 and A4 field 412, and variable length
Frame Body field 414 as in the example short frame format 400.
Since it is a control frame, the FCS field 716 may be sufficiently
reliable (e.g., because data is not being sent) with only 1-byte or
2-bytes or, alternatively, the FCS field 716 may be 4-bytes.
[0074] Thus, for ultra-low power paging frames, the FC field may
always include the frame control field 702 and the FCS field 716.
However, various other fields may either not be included or a
different may be included in their place. FIG. 7A illustrates an
example short control frame format that lacks the address fields
704, 706, 410, 412, the Sequence Control field 408, and the Frame
Body field 414.
[0075] According to certain aspects, the receiver address field
(A1) 704 may also be referred to as a destination address (DA)
field and the transmitter address field (A2) may also be referred
to as a source address (SA) field as shown in FIG. 7B. The DA field
704B and the SA field 706B may 0, 2, or 16 octets. According to
certain aspects, the FCS field may also be Frame Authentication
Code (FAC) field 716B. Whereas FCS is used for non-secure frames to
confirm no error bits, FAC is used for secure frame to provide
authentication of unaltered frames.
[0076] According to certain aspects, for ultra-low power paging, a
new Frame Control (FC) field format may be defined for Short
Control/Management MAC frames. According to certain aspects, the
new FC field for ultra-low power paging frames may include a new
Command subfield when the Subtype subfield in the FC field
indicates ultra-low power paging frame as the subtype as shown in
FIG. 8. According to certain aspects, the value of the Command
subfield may notify the receiver how to parse the remainder of the
frame (e.g., primary radio wake-up, clock resync, Wi-Fi Direct
Device Discovery Assist, Social Wi-Fi Discovery Assist, Association
Assist).
[0077] FIG. 8 illustrates a frame control (FC) field 702 format for
ultra-low power paging short control frames 700-700B, in accordance
with certain aspects of the present disclosure. As shown in FIG. 8,
the FC field 702 may include Protocol Version subfield 502 set to
1, the Type subfield 504 set to two to indicate control, a Subtype
subfield 806 indicating ultra low-power paging. The FC field 702
may eliminate the other subfields of the FC field 402.
Additionally, the FC field 702 may include a Command subfield 808
and up to four reserved bit subfield 818. The Command subfield 808
may provide additional signaling. For example, the Command subfield
808 may signal that the frame is a Primary Radio Wake-up frame, a
Clock Resynchronization frame, a Wi-Fi Direct Device Discovery
Assist frame, a Social Wi-Fi Discovery Assist frame, or an
Association Assist frame.
[0078] According to certain aspects, the FC field 702 format for
ultra-low power paging short control frames 700-700B may include a
message ID field 820, an address length indicator field 822, a
sequence field 824, an implicit SA field 826, a Secure field 828,
and a reserved field 830. The message ID field 820 may include the
information of the type field 504, the subtype field 806, and the
command field 808. A message ID of all zeros may indicate data
frame and any other value may indicate control frame. In one
example implementation, a value of 0 of the message ID field 820
may indicate the frame is for data, a value of 1 may indicate the
frame is for primary radio wake-up, a value of 2 may indicate the
frame is for clock synchronization, a value of 3 may indicate the
frame is for social W-Fi discovery assist, and a value of 5 may
indicate the frame is for Wi-Fi association assist.
[0079] The address length indicator field 822 may indicate length
of DA and SA. In one example implementation, the implicit SA field
826 may be set (e.g., to 0) to indicate the SA is not included in
the MAC frame or set (e.g., to 1) to indicate implicit 2-byte SA
used in FCS/FAC calculation but not transmitted in the MAC frame.
The sequence bit may be used in a data frame to indicate the frame
number (e.g., 0 or 1) and may not be used for control frames. The
secure field 828 may indicate whether FCS or FAC and length of the
FCS or FAC.
[0080] As mentioned above, the DA field 704B and SA field 706B may
have a length of 0, 2, or 16 bytes. The length of the fields may be
indicated using the 3-bytes in the address length indicator field
822. In one example implementation, a value of 000 may indicate a
0-byte DA length and SA length, a value of 001 may indicate a
0-byte DA length and 2-byte SA length, a value of 010 may indicate
a 2-byte DA length and 0-byte SA length, a value of 011 may
indicate a 2-byte DA length and 2-byte SA length, a value of 100
may indicate a 0-byte DA length and 16-byte SA length, and a value
of 101 may indicate a 16-byte DA length and 16-byte SA length.
According to certain aspects, 0-byte DA may be used in broadcast
frames and a 0-byte SA may be used for implicit SA locally assigned
by the companion radio. A 2-byte DA and/or 2-byte SA may be locally
assigned by the companion radio for a variety of applications. A
16-byte SA and/or a 16-byte DA may be randomly generated and may be
used for standalone ultra-low power radios.
[0081] In some implementations, ultra-low power paging short
control frames may be used between a station and other non-AP
stations. In some implementations, ultra-low power paging short
control frames may be used between a station and an AP. According
to certain aspects, STAs and/or APs may perform a capability
exchange in order to determine whether the STAs and/or APs support
ultra-low power communications. For example, whether the receiver
is an ultra-low power receiver and whether the transmitter is
configured to transmit ultra-low power paging frames.
Primary Radio Wake-up
[0082] According to certain aspects, an ultra-low power paging
short control frame 600 may be used as a primary radio wake-up
frame. In this case, the Command subfield 708 of the FC field 402
may be set (e.g., Command=0) to indicate that the frame is a
wake-up frame. According to certain aspects, the AP and STA agree
on a periodic schedule when the STA is to listen for ultra-low
power paging frames and synchronization frames. In an example
implementation, the periodic schedule may be configured using the
primary radio. As will be discussed in more detail below, a
synchronization frame may allow the STAs to synchronize to the AP
clock to limit clock drift.
[0083] FIG. 9 illustrates an example ultra-low power paging frame
900 for primary radio wake-up, in accordance with certain aspects
of the present disclosure. As shown in FIG. 9, the ultra-low power
paging frame 900 may include the FC field 702 and FCS field 716.
Additionally, the ultra-low power paging frame 900 may include a
2-byte RA field 904 (e.g., the A1 or DA field) and a 6-byte TA
field 906 (e.g., the A2 or SA field). The RA field 904 may contain
the short identifier (SID) of one or more non-AP STAs, for example,
the STAs that are intended to wake up and listen for a Wi-Fi
beacon. The TA field 906 may contain the address of the transmitter
(e.g., an AP address or basic service set identifier (BSSID)).
According to certain aspects, the TA field 906 may be 0-bytes where
the SA is implicit. When an STA receives the wake-up frame, the STA
may determine whether its SID matches an SID in the RA field 904
and the TA address matches the BSSID or address of the AP. The STA
may then wake up its primary Wi-Fi radio to listen for the primary
Wi-Fi beacon.
[0084] FIG. 10 illustrates an example ultra-low power paging frame
1000 for primary radio wake up. As mentioned, for implicit SA, the
ultra-low power paging frame 1000 for primary radio wake up may
omit the TA field 906. Instead, the FCS field 716 may be calculated
using the transmitter address (e.g., a pre-stored transmitter
address for an associated AP) and, thus, can confirm it is from the
proper AP. This may reduce the size of the frame by 6-bytes.
[0085] FIG. 11 illustrates an example ultra-low power paging frame
1100 for primary radio wake up. In yet another example
implementation, the STA may receive wake-up frames from other
devices than the associated AP. As shown in FIG. 11, the TA field
906 may be replaced with a Network-Wide Identifier (NWID) field
1106. The NWID may contain a NWID such as an SID, SSID, domain
name, or a hashed version of the SID or SSID. According to certain
aspects, a hashed SID or SSID may be hashed with other information
to avoid matching with a common SSID (e.g., "Home"). For example,
hashed with preshared key (PSK) credentials or domain name.
According to certain aspects, the FCS field 716 may be calculated
using a transmitter address as in the previous implementation.
[0086] This may allow a smartphone which is asleep to wander to a
new area in the network and then be woken up by another AP in the
network. This may also provide network-wide paging where if there
is a message for the smartphone it can be woken-up and alerted
anywhere in the network.
Clock Resynchronization
[0087] Clock resynchronization may allow non-AP STAs to
resynchronize to the AP clock (e.g., in order to listen for Wi-Fi
beacons from the AP). According to certain aspects, ultra-low power
paging frames may be used for clock resynchronization.
Resynchronization frames may be sent periodically to avoid allowing
the clock in the non-AP STA to drift off too far from the clock in
AP. According to certain aspects, the resynchronization frame may
be sent during the agreed time window in which wake-up frame can be
sent so that the non-AP will be in listening mode.
[0088] Due to carrier sense, it is possible the resynchronization
frame is delayed from the scheduled transmit time (e.g., to avoid
collisions or by regulations). According to certain aspects, a
field may be included in the frame to allow the non-AP receiving
STA to compensate for this delay (e.g., measured in .mu.s). For
example, the AP and STA may both maintain a counter (e.g., with a 1
.mu.s resolution). Each time the AP transmits a synchronization
frame, the AP includes the LSBs of its clock in the frame. There
may be a fixed delay from the time the LSBs of the clock are
captures until the frame is transmitted. The STA may compare the
change in the LSBs of the clock and compare it to the LSBs of its
clock to calculate the clock correction for synchronization.
[0089] FIG. 12 illustrates an example ultra low-power paging frame
1200 for clock resynchronization, in accordance with certain
aspects of the present disclosure. As shown in FIG. 12, the ultra
low-power paging frame 1200 may include FC field 702 and the FCS
field 716. The Command subfield 808 (e.g., the message ID field
820) of the FC field 702 may be set to indicate that the ultra
low-power paging frame 1200 is clock resynchronization frame. The
ultra low-power paging frame 1200 may include the RA field 904
(e.g., the A1 field 704 or the DA field 1204) and the TA field 906
(e.g., the A2 field 706 or the SA field 1206). The RA field 904 may
contain the SIDs of non-AP STAs that are scheduled by the AP to
listen for wake-up or resynchronization during the agreed time
window. According to certain aspects, the an example ultra
low-power paging frame 1200A may include a 0- or 2-byte DA field
1204 and/or a SA field 1206 and a 1-byte FCS field 716, as shown in
FIG. 12A. Additionally, the ultra low-power paging frame 1200 may
also include a TX Clock LSBs field 1208 that contains the least
significant bits (LSBs) of the AP clock. The receiving STA may use
the LSBs to correct for AP/STA clock offset. The STA may update its
local clock to resynchronize with the AP clock.
[0090] FIG. 13 illustrates an example ultra low-power paging frame
1300 for clock resynchronization, in accordance with certain
aspects of the present disclosure. In another example
implementation, the ultra-low power paging frame 1300 for clock
resynchronization may omit the TA field 906. Instead, the FCS field
716 may be calculated using the transmitter address and, hence, can
confirm it is from the proper AP. This may reduce the size of the
frame by 6-bytes. The RA field 904 could also be omitted for
broadcast frames.
[0091] In yet another example implementation, the STA may receive
clock resynchronization frames from other devices than the
associated AP. For example, although not shown in FIGS. 12-13, the
TA field 906 may be replaced with a NWID field.
Wi-Fi Direct Discovery Assist
[0092] According to certain aspects, ultra-low power paging frames
may be used for Wi-Fi Direct Discovery Assist. Wi-Fi Direct may be
used for STAs (e.g., a laptop, tablet, cell phone, etc.) to
communicate directly with other STAs (e.g., a printer, kiosk,
etc.). In Wi-Fi Direct Discovery, the STA receiver may have a high
duty cycle (e.g., close to 100%). Thus, STAs using Wi-Fi Direct
Discovery may benefit from the use ultra-low power discovery
assist. For example, this may enable battery-operated Wi-Fi Direct
peripherals. Ultra low-power paging may be used to save power
listening for other Wi-Fi Direct devices.
[0093] FIG. 14 illustrates an example ultra-low power paging frame
1400 for Wi-Fi Direct Discovery Assist, in accordance with certain
aspects of the present disclosure. As shown in FIG. 14, the example
ultra-low power paging frame 1400 may include the FC field 702 and
the FCS field 716. The Command subfield 808 (e.g., the Message ID
field 820) of the FC field 702 may be set to indicate that the
ultra-low power paging frame 1400 frame is a Wi-Fi Direct Discovery
Assist frame. The ultra-low power paging frame 1400 frame may
include the TA field 906 that contains the address of the
transmitting Wi-Fi Direct STA. As shown in FIG. 14, no RA field is
needed since the frame is used for discovery.
[0094] According to certain aspects, the ultra-low power paging
frame may also omit the SA and may include a Wi-Fi Direct TX Device
Address field 1408 (e.g., 6 octets) as shown in FIG. 14A.
[0095] According to certain aspects, once the STA discovers another
Wi-Fi Direct device (e.g., by receiving ultra-low power paging
frame 1400 or 1400A identifying the device in the TA field 906 or
implicitly in the FCS field 716), standard Wi-Fi Direct protocol
can take over. According to certain aspects, 5 GHz Wi-Fi devices
skip searching on 2.4 GHz periodically.
Social Wi-Fi Discovery Assist
[0096] In Social Wi-Fi, portable devices (e.g., STAs) discover
other nearby portable devices. The receiver in each STA may listen
for frames from other STAs with a high duty cycle (e.g., 100%).
According to certain aspects, ultra low-power paging frame can be
used for Social Wi-Fi to provide reduced power operation.
[0097] An ultra low-power receiver can be on with high duty cycle
(e.g. 100%) and listen for ultra low-power paging discovery assist
frames, while allowing the primary radio to spend much of its time
in sleep mode. The ultra low-power paging frame 1500 for discovery
assist may indicate to the receiving STA that there is a nearby
social Wi-Fi group and may provide information to the STA regarding
the time offset between the ultra low-power paging frame 1500 for
discovery assist and the primary radio discovery window and/or
information regarding the Cluster ID of the group. The ultra
low-power paging frame 1500 may indicate that the sender of the
frame is associated with the nearby social group. By "associated",
this could mean that the sender is a member of the nearby social
group or could indicate that the sender could be associated with
the nearby social group. The ultra low-power paging frame 1500 may
be sent out periodically.
[0098] FIG. 15 illustrates an example ultra low-power paging frame
1500 for Social Wi-Fi Discovery Assist, in accordance with certain
aspects of the present disclosure. As shown in FIG. 15, the example
ultra low-power paging frame 1500 for Social Wi-Fi Discovery Assist
may include the FC field 702 and FCS field 716. The Command
subfield 808 (e.g., message ID field 820) of the FC field 702 may
be set to indicate that example ultra low-power paging frame 1500
is a Social Wi-Fi Discovery Assist frame. Additionally, the example
ultra low-power paging frame 1500 for Social Wi-Fi Discovery Assist
includes a Discovery Window Time field 1504 and a Service ID field
1506. The Discovery Window Time field 1504 indicates the time until
the next discovery window (e.g., measures in TUs). The Service ID
field 1506 indicates the Social Wi-Fi Service ID. As shown in FIG.
15, the RA field and the TA field are not included. According to
certain aspects, as shown in FIG. 15A, the Service ID field 1506
may also be referred to as a Cluster ID field 1508, the Discovery
Window Time field 1504 may be omitted, and the FCS field 716 may be
one byte. According to certain aspects, when the STAS receives the
ultra low-power paging frame 1500 or 1500A, the STAS may notify the
primary radio and provide the discovery window time and Service ID
to the primary radio.
[0099] According to certain aspects, the transmitter address may be
used to filter out when to notify the primary radio, based on
instructions from the primary radio. In the context of Social
Wi-Fi, the TA can be 2-bytes (e.g., eliminating the common 3-byte
WFA OUI and the 1-byte Social Wi-Fi identifier). For example, a
list or table may be maintained with SSIDs, or compressed SSIDs, of
APs of interest, which may include previously associated APs.
Association Assist
[0100] According to certain aspects, ultra low-power paging frames
can be used for association assist. For example, an AP may
broadcast its service set identify (SSID) in the ultra-low power
paging frames. An STA receiving the frame, may identify an AP of
interest (e.g., home, work, etc.), notify the primary radio, and
pass along association assist information. The primary can use low
duty passive scanning to save power while still finding APs of
interest with low latency.
[0101] FIG. 16 illustrates an example ultra low-power paging frame
1600 for Association Assist, in accordance with certain aspects of
the present disclosure. The example ultra low-power paging frame
1600 may include the FC field 702 and the FCS field 716. The
Command subfield 808 (e.g., Message ID field 820) of the FC field
702 may be set to indicate that the example ultra low-power paging
frame 1600 is an Association Assist frame. Additionally, the
example ultra low-power paging frame 1600 may include a Compressed
SSID field 1604 and a Band Support Bit Map field 1606. The
Compressed SSID field 1604 may contain a 4-byte hash of the network
SSID. The Band Support Bit Map field 1606 may indicate which bands
the AP supports. As shown in FIG. 16, the A1 and A2 fields may not
be needed.
[0102] According to certain aspects, when the STA receives ultra
low-power paging frame 1600, the STA may check to see if the SSID
(e.g., in the Compressed SSID field 1604) matches any SSIDs in a
"List of Relevant SSIDs". According to certain aspects, STAs may
maintain (e.g., store in memory) a list of SSIDs of APs of interest
(e.g., home, work, etc.) which typically include previously
encountered APs or frequently used APs. According to certain
aspects, if the SSID in the ultra low-power paging frame 1600
matches an SSID in the list, the STA may notify the primary radio
and forward association assist information to the primary radio.
According to certain aspects, the primary radio can then use low
duty passive scanning to save power while still finding APs of
interest with low latency.
[0103] FIG. 17 illustrates example operations 1700 for wireless
communications, in accordance with certain aspects of the present
disclosure. Operations 1700 may be performed, for example, by a UE
(e.g., UE 120). Operations 1700 may begin, at 1702, by receiving a
paging frame (e.g., an ultra-low power short MAC paging frame) from
another apparatus via a second radio (e.g., a companion radio for
ultra-low power paging) while a first radio (e.g., a primary radio)
and is in a first power state (e.g., a sleep state) that is lower
than a second power state of the second radio.
[0104] At 1704, the UE may take one or more actions based on a
command field (e.g., Message ID field 820 or Command field 808)
included in the paging frame (e.g., in the FC field in a MAC header
of the frame). According to certain aspects, the FC field may have
a subfield (e.g., a Subtype subfield) set to a value that indicates
a type of the paging frame. The UE may parse the command field only
if the value indicates the type is a paging frame (e.g., an
ultra-low power short MAC frame). According to certain aspects, the
paging frame may also have a FCS field shorter than FCS fields of
other types of MAC frames (e.g., 2 bytes). According to certain
aspects, the paging may lack a TA field and the UE may calculate a
local FCS value, based on a TA of a virtual paging frame and
compare the local FCS value to a value of the FCS field received in
the paging frame.
[0105] According to certain aspects, the one or more actions may
include causing the first radio to exit the low power state (e.g.,
wake-up). According to certain aspects, the first radio may provide
a configuration to the second radio, and the UE may monitor for
paging frames based on the configuration. The paging frame may
include a RA field and the UE take the one or more actions only if
a SID associated with the UE matches a value of the RA field.
[0106] According to certain aspects, the one or more actions may
include adjusting a local clock of the UE. For example, the local
clock of the UE may be adjusted based on a clock value of a field
in the paging frame (e.g., TX Clock LSBs). In an example
implementation, the paging frame may be received from an AP, and
the clock value may be the LSBs of a value of a clock associated
with the AP.
[0107] According to certain aspects, the command field may indicate
the other apparatus is capable of Wi-Fi Direct. In this case, the
one or more actions may include causing the first radio to exit the
low power state so the UE can communicate with the other apparatus
via Wi-Fi Direct. For example, the second radio may notify the
first radio that the other apparatus is capable of Wi-Fi
Direct.
[0108] According to certain aspects, the command field may indicate
the other apparatus is associated with a social group. In this
case, the one or more actions may include causing the first radio
to exit the low power state so the UE can listen for a discovery
frame sent by a member of the social group. In an example
implementation, the paging frame may include a field (e.g.,
Discovery Time Window field) that indicates a time offset, relative
to a transmission time of the paging frame, corresponding to a next
discovery window for the UE to listen for discovery frames sent by
a member of the social group. The paging frame may also include a
field that indicates a service ID (e.g., Service ID field) of the
other apparatus and the UE may determine whether the service ID of
the other apparatus matches a service ID in a list of service IDs,
and cause the first radio to exit the low power state based on the
determination.
[0109] According to certain aspects, the paging frame may include a
field with association assist information. In this case, the one or
more actions may include causing the first radio to exit the low
power state to attempt association with the other apparatus using
the association assist information. For example, the association
assist information may include a SSID of the other apparatus and
the UE may associate with the other apparatus only if the indicated
SSID is in a list of relevant SSIDs (e.g., based on previous
associations) stored at the UE. The association assist information
may also include one or more frequency bands supported by the other
apparatus and the UE may determine that the UE supports at least
one of the one or more frequency bands and cause the first radio to
exit the low power state based on the determination.
[0110] According to certain aspects, the UE may determine that the
other apparatus transmits low-power paging frames and monitor for
low-power paging frames based on the determination. For example,
the UE may perform a capability exchange with the other apparatus
to determine that the apparatuses support ultra-low power paging.
As part of the capability exchange, the UE may receive an
indication from the other apparatus that the other apparatus
transmits low-power paging frames and the UE may provide an
indication that the UE is capable of receiving low-power paging
frames.
[0111] FIG. 18 illustrates example operations 1800 for wireless
communications, in accordance with certain aspects of the present
disclosure. Operations 1800 may be performed, for example, by an
apparatus (e.g., UE 120 or AP 110). Operations 1800 may begin, at
1802, by determining whether another apparatus (e.g., a UE) is
capable of receiving a paging frame, via a second radio of the
other apparatus, while a first radio is in a first power state that
is lower than a second power state of the second radio. For
example, the apparatus may receive, as part of a capability
exchange, capability information from the other apparatus
indicating the other apparatus is capable of receiving low-power
paging frames.
[0112] At 1804, based on the determination, the apparatus may
generate a paging frame (e.g., an ultra low-power short MAC paging
frame) comprising a command field (e.g., a message ID field) that
indicates one or more actions for the other apparatus to take.
According to certain aspects, the FC field of the paging frame may
have a subfield (e.g., a Subtype subfield) set to a value that
indicates a type of the paging frame. The paging frame may be a
control frame, a data frame, or a management frame. According to
certain aspects, the paging frame may also have a FCS field shorter
than FCS fields of other types of MAC frames (e.g., 2 bytes).
According to certain aspects, the paging may lack a TA field (e.g.,
a SA or A2 field) and a RA field (e.g., a DA or A1 field).
According to certain aspects, the paging frame may include a
network-wide identifier (NWID) field set to a value (e.g., SSID,
SID, hashed version of an SID, hashed version of an SSID) that
identifies a network to which the apparatus is associated.
[0113] At 1806, the apparatus may output the paging frame for
transmission to the other apparatus. According to certain aspects,
the one or more actions comprise causing the first radio to exit
the low power state. According to certain aspects, the paging frame
may include a RA field and the one or more action may include
determining whether a SID associated with the other apparatus
matches a value of the RA field and the one or more actions may
include adjusting a local clock of the other apparatus. For
example, the local clock of the other apparatus may be adjusted
based on a clock value (e.g., LSBs of a value of a clock associated
with the apparatus) of a field in the paging frame.
[0114] According to certain aspects, the command field may indicate
the apparatus is capable of Wi-Fi Direct. In this case, the one or
more actions may include causing the first radio to exit the low
power state so the other apparatus can communicate with the
apparatus via Wi-Fi Direct. For example, the apparatus may notify
the first radio, via the second radio that the apparatus is capable
of Wi-Fi Direct.
[0115] According to certain aspects, the command field may indicate
the apparatus is associated with a social group. In this case, the
one or more actions may include causing the first radio to exit the
low power state so the other apparatus can listen for a discovery
frame sent by a member of the social group. In an example
implementation, the paging frame may include a field (e.g.,
Discovery Time Window field) that indicates a time offset, relative
to a transmission time of the paging frame, corresponding to a next
discovery window for the UE to listen for discovery frames sent by
a member of the social group. The paging frame may also include a
field that indicates a service ID (e.g., Service ID field) of the
other apparatus and the UE may determine whether the service ID of
the other apparatus matches a service ID in a list of service IDs,
and cause the first radio to exit the low power state based on the
determination.
[0116] According to certain aspects, the paging frame may include a
field with association assist information. In this case, the one or
more actions may include causing the first radio to exit the low
power state to attempt association with the apparatus using the
association assist information. For example, the association assist
information may include a SSID of the apparatus and the other
apparatus may associate with the apparatus only if the indicated
SSID is in a list of relevant SSIDs (e.g., based on previous
associations) stored at the other apparatus. The association assist
information may also include one or more frequency bands supported
by the apparatus.
[0117] The methods disclosed herein comprise one or more steps or
actions for achieving the described method. The method steps and/or
actions may be interchanged with one another without departing from
the scope of the claims. In other words, unless a specific order of
steps or actions is specified, the order and/or use of specific
steps and/or actions may be modified without departing from the
scope of the claims.
[0118] As used herein, a phrase referring to "at least one of" a
list of items refers to any combination of those items, including
single members. As an example, "at least one of: a, b, or c" is
intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any
combination with multiples of the same element (e.g., a-a, a-a-a,
a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or
any other ordering of a, b, and c).
[0119] As used herein, the term "determining" encompasses a wide
variety of actions. For example, "determining" may include
calculating, computing, processing, deriving, investigating,
looking up (e.g., looking up in a table, a database or another data
structure), ascertaining and the like. Also, "determining" may
include receiving (e.g., receiving information), accessing (e.g.,
accessing data in a memory) and the like. Also, "determining" may
include resolving, selecting, choosing, establishing and the
like.
[0120] In some cases, rather than actually transmitting a frame a
device may have an interface to output a frame for transmission (a
means for outputting). For example, a processor may output a frame,
via a bus interface, to a radio frequency (RF) front end for
transmission. Similarly, rather than actually receiving a frame, a
device may have an interface to obtain a frame received from
another device (a means for obtaining). For example, a processor
may obtain (or receive) a frame, via a bus interface, from an RF
front end for reception.
[0121] The various operations of methods described above may be
performed by any suitable means capable of performing the
corresponding functions. The means may include various hardware
and/or software component(s) and/or module(s), including, but not
limited to a circuit, an application specific integrated circuit
(ASIC), or processor. Generally, where there are operations
illustrated in figures, those operations may have corresponding
counterpart means-plus-function components with similar numbering.
For example, operations 1700 and operations 1800 illustrated in
FIG. 17 and FIG. 18, respectively, correspond to means 1700A and
means 1800A illustrated in FIG. 17A and FIG. 18A, respectively.
[0122] For example, means for transmitting (or means for outputting
for transmission) may comprise a transmitter (e.g., the transceiver
222) and/or an antenna(s) 224 of the access point 110, the
transmitter (e.g., the transceiver 254) and/or antenna(s) 252 of
the user terminal 120 illustrated in FIG. 2, and/or the transmitter
310 and/or antenna(s) 316 of the wireless device 302 illustrated in
FIG. 3. Means for receiving (or means for obtaining) may comprise a
receiver (e.g., the transceiver 222) and/or an antenna(s) 224 of
the access point 110, the receiver (e.g., the transceiver 254)
and/or antenna(s) 252 of the user terminal 120 illustrated in FIG.
2, and/or the receiver 312 and/or antenna(s) 316 of the wireless
device 302 illustrated in FIG. 3. Means for processing, means for
adjusting, means for generating, means for parsing, means for
calculating, means for comparing, means for causing, means for
determining, means for monitoring, means for notifying, means for
computing, means for associating, means for listening, means for
taking, and means for providing may comprise a processing system,
which may include one or more processors, such as the RX data
processor 242, the RX spatial processor 240, the TX data processor
210, the TX spatial processor 220, and/or the controller 230 of the
access point 110, the RX data processor 270, the RX spatial
processor 260, the TX data processor 288, the TX spatial processor
290, and/or the controller 280 of the user terminal 120 illustrated
in FIG. 2, and/or the signal detector 318 and/or the processor 304
of the wireless device 302.
[0123] According to certain aspects, such means may be implemented
by processing systems configured to perform the corresponding
functions by implementing various algorithms (e.g., in hardware or
by executing software instructions) described above for providing
an immediate response indication in a PHY header. For example, an
algorithm for receiving a paging frame from an apparatus via a
second radio while a first radio is in a first power state that is
lower than a second power state of the second radio and an
algorithm for taking one or more actions based on a command field
included in the paging frame. In another example, an algorithm for
determining whether another apparatus is capable of receiving a
paging frame, via a second radio of the other apparatus, while a
first radio is in a first power state that is lower than a second
power state of the second radio, an algorithm for based on the
determination, generating a paging frame comprising a command field
that indicates one or more actions for the other apparatus to take,
and an algorithm for transmitting the paging frame to the other
apparatus.
[0124] The various illustrative logical blocks, modules and
circuits described in connection with the present disclosure may be
implemented or performed with a general purpose processor, a
digital signal processor (DSP), an application specific integrated
circuit (ASIC), a field programmable gate array (FPGA) or other
programmable logic device (PLD), discrete gate or transistor logic,
discrete hardware components, or any combination thereof designed
to perform the functions described herein. A general-purpose
processor may be a microprocessor, but in the alternative, the
processor may be any commercially available processor, controller,
microcontroller, or state machine. A processor may also be
implemented as a combination of computing devices, e.g., a
combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration.
[0125] If implemented in hardware, an example hardware
configuration may comprise a processing system in a wireless node.
The processing system may be implemented with a bus architecture.
The bus may include any number of interconnecting buses and bridges
depending on the specific application of the processing system and
the overall design constraints. The bus may link together various
circuits including a processor, machine-readable media, and a bus
interface. The bus interface may be used to connect a network
adapter, among other things, to the processing system via the bus.
The network adapter may be used to implement the signal processing
functions of the PHY layer. In the case of a user terminal 120 (see
FIG. 1), a user interface (e.g., keypad, display, mouse, joystick,
etc.) may also be connected to the bus. The bus may also link
various other circuits such as timing sources, peripherals, voltage
regulators, power management circuits, and the like, which are well
known in the art, and therefore, will not be described any further.
The processor may be implemented with one or more general-purpose
and/or special-purpose processors. Examples include
microprocessors, microcontrollers, DSP processors, and other
circuitry that can execute software. Those skilled in the art will
recognize how best to implement the described functionality for the
processing system depending on the particular application and the
overall design constraints imposed on the overall system.
[0126] If implemented in software, the functions may be stored or
transmitted over as one or more instructions or code on a
computer-readable medium. Software shall be construed broadly to
mean instructions, data, or any combination thereof, whether
referred to as software, firmware, middleware, microcode, hardware
description language, or otherwise. Computer-readable media include
both computer storage media and communication media including any
medium that facilitates transfer of a computer program from one
place to another. The processor may be responsible for managing the
bus and general processing, including the execution of software
modules stored on the machine-readable storage media. A
computer-readable storage medium may be coupled to a processor such
that the processor can read information from, and write information
to, the storage medium. In the alternative, the storage medium may
be integral to the processor. By way of example, the
machine-readable media may include a transmission line, a carrier
wave modulated by data, and/or a computer readable storage medium
with instructions stored thereon separate from the wireless node,
all of which may be accessed by the processor through the bus
interface. Alternatively, or in addition, the machine-readable
media, or any portion thereof, may be integrated into the
processor, such as the case may be with cache and/or general
register files. Examples of machine-readable storage media may
include, by way of example, RAM (Random Access Memory), flash
memory, ROM (Read Only Memory), PROM (Programmable Read-Only
Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM
(Electrically Erasable Programmable Read-Only Memory), registers,
magnetic disks, optical disks, hard drives, or any other suitable
storage medium, or any combination thereof. The machine-readable
media may be embodied in a computer-program product.
[0127] A software module may comprise a single instruction, or many
instructions, and may be distributed over several different code
segments, among different programs, and across multiple storage
media. The computer-readable media may comprise a number of
software modules. The software modules include instructions that,
when executed by an apparatus such as a processor, cause the
processing system to perform various functions. The software
modules may include a transmission module and a receiving module.
Each software module may reside in a single storage device or be
distributed across multiple storage devices. By way of example, a
software module may be loaded into RAM from a hard drive when a
triggering event occurs. During execution of the software module,
the processor may load some of the instructions into cache to
increase access speed. One or more cache lines may then be loaded
into a general register file for execution by the processor. When
referring to the functionality of a software module below, it will
be understood that such functionality is implemented by the
processor when executing instructions from that software
module.
[0128] Also, any connection is properly termed a computer-readable
medium. For example, if the software is transmitted from a website,
server, or other remote source using a coaxial cable, fiber optic
cable, twisted pair, digital subscriber line (DSL), or wireless
technologies such as infrared (IR), radio, and microwave, then the
coaxial cable, fiber optic cable, twisted pair, DSL, or wireless
technologies such as infrared, radio, and microwave are included in
the definition of medium. Disk and disc, as used herein, include
compact disc (CD), laser disc, optical disc, digital versatile disc
(DVD), floppy disk, and Blu-ray.RTM. disc where disks usually
reproduce data magnetically, while discs reproduce data optically
with lasers. Thus, in some aspects computer-readable media may
comprise non-transitory computer-readable media (e.g., tangible
media). In addition, for other aspects computer-readable media may
comprise transitory computer-readable media (e.g., a signal).
Combinations of the above should also be included within the scope
of computer-readable media.
[0129] Thus, certain aspects may comprise a computer program
product for performing the operations presented herein. For
example, such a computer program product may comprise a
computer-readable medium having instructions stored (and/or
encoded) thereon, the instructions being executable by one or more
processors to perform the operations described herein. For example,
instructions for receiving a paging frame from an apparatus via a
second radio while a first radio is in a first power state that is
lower than a second power state of the second radio and
instructions for taking one or more actions based on a command
field included in the paging frame. In another example,
instructions for determining whether another apparatus is capable
of receiving a paging frame, via a second radio of the other
apparatus, while a first radio is in a first power state that is
lower than a second power state of the second radio, instructions
for based on the determination, generating a paging frame
comprising a command field that indicates one or more actions for
the other apparatus to take, and instructions for transmitting the
paging frame to the other apparatus.
[0130] Further, it should be appreciated that modules and/or other
appropriate means for performing the methods and techniques
described herein can be downloaded and/or otherwise obtained by a
user terminal and/or base station as applicable. For example, such
a device can be coupled to a server to facilitate the transfer of
means for performing the methods described herein. Alternatively,
various methods described herein can be provided via storage means
(e.g., RAM, ROM, a physical storage medium such as a compact disc
(CD) or floppy disk, etc.), such that a user terminal and/or base
station can obtain the various methods upon coupling or providing
the storage means to the device. Moreover, any other suitable
technique for providing the methods and techniques described herein
to a device can be utilized.
[0131] It is to be understood that the claims are not limited to
the precise configuration and components illustrated above. Various
modifications, changes and variations may be made in the
arrangement, operation and details of the methods and apparatus
described above without departing from the scope of the claims.
* * * * *