U.S. patent application number 15/070522 was filed with the patent office on 2016-09-15 for wireless station and methods for tof positioning using reverse-direction grant.
The applicant listed for this patent is Intel Corporation. Invention is credited to Yuval Amizur, Jonathan Segev, Adrian P. Stephens.
Application Number | 20160270124 15/070522 |
Document ID | / |
Family ID | 50978983 |
Filed Date | 2016-09-15 |
United States Patent
Application |
20160270124 |
Kind Code |
A1 |
Stephens; Adrian P. ; et
al. |
September 15, 2016 |
WIRELESS STATION AND METHODS FOR TOF POSITIONING USING
REVERSE-DIRECTION GRANT
Abstract
Embodiments of a communication station (STA) and method for
time-of-flight (ToF) positioning in a wireless network are
generally described herein. In some embodiments, an initiating
station may transmit a message M1 carrying a high-throughput
control (HTC) field that includes a reverse direction grant (RDG)
bit. The RDG indication grants permission to a responding station
to send information back to the initiating station. The message M1
may be a timing measurement action frame. An ACK frame may be
received from Me responding station to acknowledge receipt of the
message M1. The ACK frame may optionally carry an HTC field that
includes amore PPDU indication to indicate whether a PPDU (e.g.,
contained in message M2) is to follow the ACK frame. The message M2
may be received from the responding station and may include timing
measurement information from a current and/or one or more previous
ToF message exchanges.
Inventors: |
Stephens; Adrian P.;
(Cottenham, GB) ; Amizur; Yuval; (Kfar-Saba,
IL) ; Segev; Jonathan; (Tel Mond, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Intel Corporation |
Santa Clara |
CA |
US |
|
|
Family ID: |
50978983 |
Appl. No.: |
15/070522 |
Filed: |
March 15, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14124444 |
Dec 6, 2013 |
9313811 |
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PCT/US2013/048628 |
Jun 28, 2013 |
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15070522 |
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61738716 |
Dec 18, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 1/1678 20130101;
H04L 1/1664 20130101; H04W 74/0891 20130101 |
International
Class: |
H04W 74/08 20060101
H04W074/08; H04L 1/16 20060101 H04L001/16 |
Claims
1. A method for time-of-flight (ToF) positioning performed by an
initiating station, the method comprising: transmitting a message
M1 carrying a high-throughput control (HTC) field, the HTC field
including a reverse direction grant (RDG) indication, the RDG
indication granting permission to a responding station to send
information back to the initiating station, the message M1 being a
timing measurement action frame; receiving an acknowledgement (ACK)
frame to acknowledge receipt of the message M1, the ACK frame
carrying an HTC field that includes an indication to indicate
whether a separate frame is to follow the ACK frame; and receiving
a message M2 from the responding station, the message M2 including
timing measurement information from at least at one of a current
and a previous ToF message exchange.
Description
PRIORITY CLAIM
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/124,444, filed Dec. 6, 2013, which is a
U.S. National Stage Filing under 35 U.S.C. 371 from International
Application No. PCT/US2013/048628, filed Jun. 28, 2013, published
in English as international Publication No. WO 2014/099030 on Jun.
26, 2014, which claims the benefit of priority to U.S. Provisional
Patent Application Ser. No. 61/738,716, filed Dec. 18, 2012, of
which are incorporated herein by reference in their entireties and
made a part hereof.
TECHNICAL FIELD
[0002] Embodiments pertain to wireless networks. Some embodiments
relate to wireless networks that operate in accordance with one of
the IEEE 802.11 standards including the IEEE 802.11-2012 standards.
Some embodiments relate to time-of-flight (ToF) positioning. Some
embodiments relate to location determination. Some embodiments
relate to indoor navigation.
BACKGROUND
[0003] Outdoor navigation and positioning has been widely deployed
thanks to the development of various global
navigation-satellite-systems (GNSS) as well as various cellular
systems. Indoor navigation and positioning differs from the outdoor
navigation and positioning since the indoor environment does not
enable the reception of signals from satellites or cellular base
stations as well as in the outdoor environment. As a result,
accurate and real-time indoor navigation and positioning are
difficult to achieve.
[0004] Thus there are general needs for improved navigation and
positioning methods. There are also general needs for improved
navigation and positioning methods suitable for indoor
environments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 illustrates a wireless network in accordance with
some embodiments;
[0006] FIG. 2 illustrates a procedure for time-of-flight (ToF)
positioning using a reverse-direction grant (RDG) in accordance
with some embodiments;
[0007] FIG. 3 illustrates a procedure for ToF positioning without a
final acknowledgement (ACK) frame in accordance with some other
embodiments;
[0008] FIG. 4 illustrates a procedure for ToF positioning in which
a message M2 includes additional timing measurement information in
accordance with sonic other embodiments;
[0009] FIG. 5 illustrates a procedure for ToF positioning using an
aggregated media-access-control protocol data unit (A-MPDU) in
accordance with some other embodiments;
[0010] FIG. 6 illustrates the use of an A-MPDU in accordance with
some embodiments;
[0011] FIG. 7 illustrates a procedure for ToF positioning in
accordance with some other embodiments; and
[0012] FIG. 8 is a functional diagram of a communication station in
accordance with some embodiments.
DETAILED DESCRIPTION
[0013] The following description and the drawings sufficiently
illustrate specific embodiments to enable those skilled in the art
to practice them. Other embodiments may incorporate structural,
logical, electrical, process, and other changes. Portions and
features of some embodiments may be included in, or substituted
for, those of other embodiments. Embodiments set forth in the
claims encompass all available equivalents of those claims.
[0014] FIG. 1 illustrates various network elements of a wireless
network in accordance with some embodiments. Wireless network 100
includes a plurality of communication stations (STAs) and one or
more access points (APs) which may communicate in accordance with
IEEE 802.11 communication techniques. The communication stations
may be mobile devices that are non-stationary and do not have fixed
locations. The one or more access points may be stationary and have
fixed locations. The stations may include an initiating station 102
and one or more responding stations 104. The initiating station 102
may be a communication station that initiates ToF positioning with
the responding station 104 to determine its location. The ToF
positioning procedure may include the exchange of messages
including the exchange of a message M1 and a message M2, as
described in more detail below.
[0015] In some embodiments, a reverse direction (RD) mechanism may
be used. In these embodiments, an initiator (such as an initiating
station 102) is able choose whether or not to use an IEEE 802.11
reverse direction (RD) grant for ToF measurements (e.g., by setting
a RD indicator or bit). In some of these embodiments that use the
RD mechanism, a responder (such as a responding station 104) can
choose whether to use an optimized sequence for ToF message
exchange by setting certain one or more signaling bits. In some of
these embodiments that use the RD mechanism, a responder can choose
whether or not to aggregate the ACK and the message M2. These
embodiments are described in more detail below.
[0016] In some embodiments, the responder can choose whether to use
current or previous timing measurement information. In these
embodiments, the responder can choose whether to use a current or
previous measurement by setting a bit in a message M2 or by the
inclusion of dialog tokens that identify a specific message M1
verses the reported timing measurement information e.g., a (t3-t2)
value). These embodiments are described in more detail below.
[0017] Some embodiments may eliminate the use of an ACK. frame for
acknowledging receipt of the message M2. Some of these embodiments
provide for repeated transmissions of timing measurement
information (e.g., a (t3-t2) value) to help counteract the loss of
the ACK to the message M2. Some of these embodiments may cause a
final ACK not be generated through the use of an `Action No ACK`
frame. These embodiments are discussed in more detail below.
[0018] Some embodiments provide for mutual ToF discovery using two
PPDUs per measurement. In these embodiments, message M1 may be
arranged to carry a timing measurement information of the
initiating station (e.g., a (t1-t4) value) allowing both the
initiator and the responder to determine ToF information. In some
of these embodiments, message M1 may be arranged to carry a dialog
token related to timing measurement information of the initiating
station (e.g., a (t1-t4) value) to allow the responder to determine
that stored timing measurement information (e.g., a (t3-t2) value)
corresponds to the same measurement.
[0019] In some embodiments, the initiating station 102 may be a
positioning station and may determine its location relative to one
or more responding stations e.g., cooperating stations and/or one
or more access points) The cooperating stations may be either IEEE
802.11 configured communication stations (STAs) or APs. In other
embodiments, the initiating 102 may determine its location in
geo-coordinates. In some embodiments, the responding station may be
able to determine its location either in relative or in
geo-coordinates.
[0020] FIG. 2 illustrates a procedure for ToF positioning using RDG
in accordance with some embodiments. As illustrated in FIG. 2, the
initiating station 102 may be arranged to transmit a message M1 202
carrying a high-throughput control (HTC) field. The HTC field may
include a reverse direction grant (RDG) indication. The RDG
indication may grant permission to the responding station 104 to
send information back to the initiating station 102 during a
transmission opportunity (TXOP) of the initiating station 102. The
message M1 202 may be a timing measurement action frame. The timing
measurement action frame may be a unicast management frame. In some
embodiments, the RDG indication may be an RDG bit.
[0021] The initiation station 102 may receive an ACK frame 204 from
the responding station 104 during the TXOP to acknowledge receipt
of the message M1 202. The ACK frame 204 may optionally carry an
HTC field that includes an indicator to indicate whether a separate
frame is to follow the ACK frame 204 during the TXOP. The
initiating station 102 may also receive a message M2 206 from the
responding station 104 during the TXOP. The message M2 206 may
include timing measurement information from either a current or a
previous ToF message exchange. As discussed in more detail below,
the message M2 206 may include timing measurement information from
a current and/or one or more previous ToF message exchanges.
[0022] The indicator included in the HTC field of ACK frame 204 may
comprise one or more signaling bits to indicate whether a separate
frame is to follow the ACK frame 204. In some embodiments, the
indicator may comprise a more PPDU indication to indicate whether
or not a separate frame (contained in a separate PPDU) is to follow
the ACK frame 204 during the TXOP. In some embodiments, the
indicator may comprise a more PPDU bit.
[0023] In these embodiments, when the initiating station 102 sets
the RDG indication in the message M1 202, the responding station
104 is granted permission to optionally send information hack
during the TXOP. For example, instead of a conventional ACK frame,
the responding station 104 may send information back during the
TXOP which may include an ACK frame with additional fields. The
TXOP may have been obtained by the initiating station 102 prior to
transmitting message M1 202. In these embodiments, the message M2
206 may correspond to the separate frame that was indicated to
follow the ACK frame 204. The separate frame may include a packet
protocol data unit such as a physical-layer convergence protocol
(MCP) data unit (i.e., a PPDU) although this is not a
requirement.
[0024] In these embodiments, message M1 202, ACK frame 204, the
message M2 206, and ACK frame 208 may be sent during the TXOP that
has been obtained by the initiating station. Since the ToF message
exchange takes place with the TXOP, only a single channel access is
required thus avoiding delay and eliminating collisions.
[0025] In some embodiments, the RDG signaling (e.g., using RDG
indication) and the more PPDU signaling (e.g., using a more PPDU
indication) may occur in the same field (e.g., the HTC field). The
signaling may be distinguished depending on whether the
transmitting station is the current TXOP holder. For example, if
the transmitting station is the current TXOP holder (i.e., the
initiating station 102), the signaling would be interpreted as an
RDG indication. If the transmitting station is not the current TXOP
holder (i.e., the responding station 104), the signaling would be
interpreted as a more PPDU indication.
[0026] As discussed in more detail below, a sequence number or
token may be used to indicate whether the timing measurement
information included in message M2 206 is for a current or a
previous ToF message exchange.
[0027] Various embodiments disclosed herein may provide for a
reduction in the number of channel access attempts and frames.
Furthermore, these embodiments help cope with hardware that takes a
long time to make a timing measurements.
[0028] In some embodiments, the message M1 202 may be a timing
measurement action frame in accordance with 802.11(v), while in
some other embodiments that provide finer measurement resolution;
the message M1 202 may be a fine-timing measurement action frame in
accordance with 802.11REVmc. The message M1 202 may refer to an M1
frame and the message M2 206 may refer to an M2 frame. In some
embodiments, the message M1 202 may be used to initiate ToF
positioning with another station.
[0029] In some embodiments, the message M1 may be a first timing
measurement action frame and the message M2 may be a second timing
measurement action frame. In some embodiments, the timing
measurement action frames may be timing measurement frames. In some
embodiments, a Media Access Control (MAC) Sublayer Management
Entity (MLME) constructs the timing measurement frames.
[0030] In some embodiments, the timing measurement information may
be a t2 value and a t3 value (i.e., two values) or a t3-t2 value
(i.e., a single difference value). In these embodiments, the
initiating station may be arranged to parse the structure of the
message M2 206. By parsing the structure of message M2 206, the
initiating station 102 can determine whether the message M2 206
contains either a t2 value and a t3 value (i.e., two values) or a
t3-t2 value (i.e., a single difference value). In some of these
embodiments, the message M2 206 may include different elements or
employ sub-element coding to allow the initiation station to parse
the structure of message M2 206.
[0031] In some embodiments, t2 may he a time-stamp against a local
clock associated with the arrival of message M1 at the responding
station 104, and t3 may be a time-stamp against the local clock
associated with transmission of message M2 by the responding
station 104 (i.e., measured against the same clock as t2). In some
embodiments, t1 may be a time-stamp against a local clock
associated with the transmission of message M1 by the initiating
station 102 and t4 may be a time-stamp against the local clock
associated with receipt of the acknowledgement frame that
acknowledges receipt of the message M1 (i.e., measured against the
same clock as t1).
[0032] In some embodiments, the t2 value is the time that the
message M1 202 arrived at the responding station 104, and the t3
value is time that the ACK frame 204 is sent by the responding
station 104. The inclusion of both t2 value and t3 value may be
more optimal as it may allow a particular and more straightforward
way to calibrate for difference in the clock rates at the two
stations for increased ToF accuracy. Furthermore, inclusion of a
single value (t3-t2) may allow the relative timing drift between
the recipient and the responding stations to be tracked for
increased ToF accuracy.
[0033] In some embodiments, when the more PPDU indication in the
HTC field of the ACK frame 204 indicates that a separate frame
(e.g., containing a PPDU) is to follow, the message M2 206 may be
the separate frame that follows. In these embodiments, the
initiating station 102 may wait for receipt of the message M2 206.
When the more PPDU indication in the HTC field of the ACK 204 does
not indicate that a PPDU is to follow, the message M2 206 is not
sent by the responding station 104 and the initiation station 102
may refrain from waiting for receipt of a message M2 206.
[0034] In some embodiments, the initiating station 102 and the
responding station 104 may be either mutually associated although
this is nota requirement. The stations may be mutually unassociated
with each other prior to the ToF message exchange illustrated in
FIG. 2.
[0035] In FIG. 2, a plus sign (`+`) is used to indicate that there
is an additional optional field. For example, message M1 202
includes the optional HTC field which may include signaling bits
such as the RDG indication. For example, the ACK frame 204
illustrated in FIG. 2 includes the optional HTC field which may
include a more PPDU indication, which may be set to one. The RDG
indication may include one or more signaling bits.
[0036] In some embodiments, the message M2 206 may be in arranged
to include a previous-exchange indication to indicate whether the
timing measurement information relates to a current or a previous
ToF message exchange between the responding station 104 and the
initiating station 102 (i.e., an exchange between the same
stations).
[0037] In some embodiments, when the previous-exchange indication
indicates that the timing measurement information relates to the
current ToF exchange, the initiating station 102 may calculate a
ToF using a t1 value and a t4 value from the current exchange and
the timing measurement information (e.g., t3-t2) received in the
message M2 206. When the previous-exchange indication indicates
that the timing measurement information relates to a previous ToF
exchange, the initiating station 102 may calculate a ToF using a t1
value and a t4 value from a previous exchange and the timing
measurement information (e.g., t3-t2) received in the message M2
206. In some embodiments, the following equation may be used to
determine the ToF: ToF=[(t4-t1)-(t3-t2)]/2, although the scope of
the embodiments is not limited in this respect.
[0038] In some embodiments, the previous-exchange indication that
may be included in M2 206 comprises a one-bit flag. In some
embodiments, the previous-exchange indication may indicate whether
the timing measurement information relates to a current or a
previous exchange. In some embodiments, the previous-exchange
indication may comprise a previous exchange flag.
[0039] In some embodiments, the message M1 202 may be arranged to
further include a dialog token that indicates a specific instance
of a timing measurement action frame (i.e., either the current or a
previous instance of a message M1). The previous-exchange
indication included in the message M 206 may comprise the dialog
token from the specific instance of the timing measurement action
frame from which the timing measurement information that is
included in the message M2 206 had been determined. In some of
these embodiments, the dialog token may be an integer that is
incremented to indicate specific instances of the message M1. The
specific instance of a message M1 may be any of several prior
instances of a message M1 that is a timing measurement action
frame.
[0040] In some embodiments, the previous instance of a message M1
may be part of a prior message exchange that occurred within the
current TXOP obtained by the initiating station 102, although this
is not a requirement as the message exchange may have occurred in a
previous TXOP (e.g. aperiodic 1 s range fix). The use of previous
instances of the (t4-t1) value may provide for adaptive support of
fast or slow measurement of t2, t3 at the responding station 104
(or access point (AP)), thus enabling better use of the
computational resources of the responding station 104. In some
embodiments, the prior message exchange may have occurred within
the current TXOP when taking place in a rapid burst of measurements
to produce a single range fix.
[0041] In some embodiments, when the message M2 206 may include a
dialog token indicating a specific instance of a prior message M1,
the initiating station 102 may calculate a ToF (box 207) using a
(t4-t1) value corresponding to the specific instance of the message
M1 indicated in the dialog token. In these embodiments, the
initiating station 102 may only generate a ToF result when the
dialog token received in the message M2 matches a dialog token of a
recorded (t4-t1) value.
[0042] In some embodiments, when the more PPDU indication in the
HTC field carried by the ACK frame 204 is set to one, the more PPDU
indication may indicate that that a PPM will follow the ACK frame
204 after a short-interframe space (SIFS) 205, the PPDU that is to
follow being the message M2 206. When the more PPDU indication is
set to zero, the more PPDU indication may indicate that a PPDU will
not follow the ACK frame 204 and message M2 206 will not be
sent.
[0043] In some embodiments, when the ACK frame 204 includes the HTC
field, the ACK frame 204 may be contained in a control wrapper
frame. In some embodiments, since the ACK frame 204 includes an
optional HTC field, it may be contained in a control wrapper frame
to avoid issues with legacy systems (e.g., so that it is readable
by legacy systems).
[0044] In some embodiments, the responding station 104 may be
arranged to transmit the ACK frame 204 after a SIFS 203 after
receipt of the message M1 202. The responding station 104 may be
arranged to transmit the message M2 206 after no more than a SIFS
205 after transmission of the ACK frame 204. In some alternate
embodiments, the responding station 104 may he arranged to transmit
the message M2 206 after a no more than a point coordination
function (PCF) interframe spacing (PIFS) after transmission of the
ACK frame 204.
[0045] In accordance with embodiments, since message M2 206 is sent
no later than a predetermined time after the transmission of ACK
frame 204, the initiation station 102 knows when message M2 206
will arrive is does not need to wait an indeterminable amount of
time. Furthermore, the initiating station 102 can reliably go to
sleep or go to a different channel without having to wait an
arbitrary period of time for receipt of message M2 206. This is
particular beneficial if message M2 206 is not transmitted or
lost.
[0046] Some embodiments, the initiating station 102 may be a mobile
station and the responding station 104 may be an AP, although the
scope of the embodiments is not limited in this respect. In other
embodiments, the initiating station 102 may be an AP and the
responding station 104 may be a mobile station. In some
embodiments, the initiating station 102 and the responding station
104 may be any two IEEE 802.11 configured stations. In some
peer-to-peer (P2P) embodiments, the initiating station 102 and the
responding station 104 may be two peer non-AP stations that may
communicate in accordance with a direct link setup (DLS) or
tunneled DLS (TDLS) protocol.
[0047] In some embodiments, the initiating station 102 may be
arranged to send an ACK frame 208 to the responding station 104 to
acknowledge receipt of the message M2 206. In other embodiments, no
acknowledgement frame 208 is sent. In these other embodiments, the
message M2 may be an Action No ACK management frame.
[0048] FIG. 3 illustrates a procedure for ToF positioning without a
final acknowledgement frame in accordance with some other
embodiments. In these embodiments, no acknowledgement frame, such
as acknowledge frame 208 (FIG. 2) is sent. In these other
embodiments, the message M2 306 may be an Action No ACK management
frame.
[0049] In these embodiments, when the message M2 306 is an Action
No ACK management frame, the initiating station 102 will refrain
from sending an ACK frame to acknowledge the message M2. The use of
sending an ACK frame 208 to the responding station 104 may be of
little value to a ToF message exchange since the data in message M2
may expire quickly. Furthermore, the responding station 104 cannot
always be sure if the initiating station 102 is on channel and
awake to receive the message M2 206. In the embodiments illustrated
in FIG. 3, since no ACK frame 208 (FIG. 2) is transmitted,
retransmissions of the message M2 by the responding station would
not occur.
[0050] FIG. 4 illustrates a procedure for ToF positioning in which
a message M2 includes additional timing measurement information in
accordance with some other embodiments. In these embodiments, when
the message M2 406 (FIG. 4) is an Action No ACK management frame,
the message M2 406 may be arranged to include the timing
measurement information from a current ToF message exchange and one
or more indicated previous ToF message exchanges. This provides
additional robustness since no ACK frame, such as ACK frame 208
(FIG. 2)) is transmitted by the responding station 104.
[0051] In some of these embodiments, the message M2 406 may include
the latest or more recent timing measurement information (e.g.,
from the current and the next most recent ToF message exchange). As
illustrated in FIG. 4, current timing measurement information is
illustrated the message M2 406 as (t3-t2) and the timing
measurement information from the previous exchange is illustrated
the message M2 406 as (t3'-t2'). These embodiments may result in
increasing the reliability of the information in the message M2 406
since no ACK frame, such as ACK frame 208, is to be
transmitted.
[0052] In the example illustrated in FIG. 4, t2' and t3' may be
buffered from the previous message exchange. For the next message
exchange t2 and t3 become the new t2' and t3' respectively buffered
from the previous message exchange.
[0053] In some embodiments, this repetition like code scheme may be
extended to almost any depth n (i.e., t2', t3') . . . (t2.sup.n,
t3.sup.n) and may be arranged to be time sensitive such that t2',
t3'. . . (t2', t3') are kept only up to a certain duration from
their original M2 transmission frame. The duration may be fixed,
dynamic or semi-dynamic, advertised, or not. The duration may be
the result of local load (e.g., due to internal buffer size). In
some embodiments, message M2 406 may identify or indicate which
recent ToF message exchange the timing measurement information is
associated with.
[0054] FIG. 5 illustrates a procedure for ToF positioning using an
A-MPDU in accordance with some other embodiments. In these
embodiments, the ACK frame 204 and the message M2 306 comprises an
aggregated media-access-control protocol data unit (A-MPDU) 506. In
these embodiments, the ACK to the message M1 202 (i.e., ACK frame
204) and the message M2 (206, 306 or 406) may be included as part
of a single A-MPDU 506 transmitted by the responding station 104.
In these embodiments, the more PPDU indication in the HTC field of
ACK frame 204 may be set (e.g., to zero) to indicate that a
separate frame will not follow since both the ACK frame 204 and the
message M2 306 are part of a single PPDU (i.e., A-MPDU 506). The
A-MPDU 506 may be configured in accordance the IEEE 802.11-2012
standard, for example. FIG. 6 further illustrates the use of an
A-MPDU 506 to transmit an ACK to message M1 202 and a message
M2.
[0055] FIG. 7 illustrates a procedure for ToF positioning in
accordance with some other embodiments. In these embodiments, the
initiating station 102 may configure the message M1 702 (FIG. 7) to
further include timing measurement information (e.g., a single
difference value (t4-t1) or two values (t4, t1)) and a dialog token
related to the included timing measurement information. The dialog
token may indicate a ToF message exchange to which the timing
measurement information is associated with. These embodiments that
include initiating station timing measurement information (e.g.,
(t4-t1) or (t4, t1)) in the message M1 702 may allow both the
responding station 104 as well as the initiating station 102 to
calculate a ToF. In some embodiments, the responding station 104
may use the dialog token to check that previous recorded t2, t3
values relate to the same M1 frame before using it to determine a
ToF.
[0056] FIG. 8 is a functional diagram of a communication station in
accordance with some embodiments. Communication station 800 may be
suitable for use as either a responding station, such as responding
station 104 (FIG. 1), or an initiating station, such as initiating
station 102 (FIG. 1). Communication station 800 may include
physical layer circuitry 802 for transmitting and receiving
messages (e.g., frames) as described herein and processing
circuitry 804 for performing the various operations described
herein.
[0057] In some embodiments, the physical layer circuitry 802 and
the processing circuitry 804 may be configured to transmit a
message M1 202 carrying HTC field, receive an ACK frame 204 to
acknowledge receipt of the message M1 202, and receive a message M2
206 from the responding station 104. The message M2 206 includes
timing measurement information from either a current or a previous
ToF message exchange.
[0058] In some embodiments, the communication station 800 may be
part of a portable wireless communication device, such as a
personal digital assistant (PDA), a laptop or portable computer
with wireless communication capability, a web tablet, a wireless
telephone, a smartphone, a wireless headset, a pager, an instant
messaging device, a digital camera, an access point, a television,
a medical device (e.g., a heart rate monitor, a blood pressure
monitor, etc.), or other device that may receive and/or transmit
information wirelessly.
[0059] In some embodiments, the communication station 800 may
include one or more antennas. The antennas may comprise one or more
directional or omnidirectional antennas, including, for example,
dipole antennas, monopole antennas, patch antennas, loop antennas,
microstrip antennas or other types of antennas suitable for
transmission of RF signals. In some embodiments, instead of two or
more antennas, a single antenna with multiple apertures may be
used. In these embodiments, each aperture may be considered a
separate antenna. In some multiple-input multiple-output (MIMO)
embodiments, the antennas may be effectively separated to take
advantage of spatial diversity and the different channel
characteristics that may result between each of antennas and the
antennas of a transmitting station.
[0060] In some embodiments, the communication station 800 may
include one or more of a keyboard, a display, a non-volatile memory
port, multiple antennas, a graphics processor, an application
processor, speakers, and other mobile device elements. The display
may be an LCD screen including a touch screen.
[0061] Although communication station 800 is illustrated as having
several separate functional elements, one or more of the functional
elements may be combined and may be implemented by combinations of
software-configured elements, such as processing elements including
digital signal processors (DSPs), and/or other hardware elements.
For example, some elements may comprise one or more
microprocessors. DSPs, field-programmable gate arrays (FPGAs),
application specific integrated circuits (ASICs), radio-frequency
integrated circuits (RFICs) and combinations of various hardware
and logic circuitry for performing at least the functions described
herein. In some embodiments, the functional elements of the
communication station 800 may refer to one or more processes
operating on one or more processing elements.
[0062] Embodiments may be implemented in one or a combination of
hardware, firmware and software. Embodiments may also be
implemented as instructions stored on a computer-readable storage
device, which may be read and executed by at least one processor to
perform the operations described herein. A computer-readable
storage device may include any non-transitory mechanism for storing
information in a form readable by a machine (e.g., a computer). For
example, a computer-readable storage device may include read-only
memory (ROM), random-access memory (RAM), magnetic disk storage
media, optical storage media, flash-memory devices, and other
storage devices and media. In some embodiments, the communication
station 800 may include one or more processors and may be
configured with instructions stored on a computer-readable storage
device.
[0063] In one example, method for time-of-flight (ToF) positioning
performed by an initiating station, the method comprises:
[0064] transmitting a message M1 carrying a high-throughput control
(HTC) field, the HTC field including a reverse direction grant
(RDG) indication, the RDG indication granting permission to a
responding station to send information back to the initiating
station, the message M1 being a timing measurement action frame;
receiving an acknowledgement (ACK) frame to acknowledge receipt of
the message M1, the ACK frame carrying an HTC field that includes
an indication to indicate whether a separate frame is to follow the
ACK frame; and receiving a message M2 from the responding station,
the message M2 including timing measurement information from at
least at one of a current and a previous ToF message exchange.
[0065] In one example, the indication in the HTC field of the ACK
frame is a more physical-layer convergence protocol (PLCP) data
unit (PPDU) indication, the timing measurement information
comprising either a t2 value and t3 or a t3-t2 value, and
[0066] the t2 value is a time-stamp associated with the arrival of
the message M1 at the responding station and the t3 value is a
time-stamp associated with transmission of the message M2 by the
responding station.
[0067] In one example, when the indication in the HTC field of the
ACK frame indicates that a PPDU is to follow, the message M2
comprises the PPDU and the method includes the initiating station
waiting for receipt of the message M2; and
[0068] when the indication in the HTC field of the ACK does not
indicate that a PPDU is to follow, the message M2 is not sent by
the responding station and the method includes the initiation
station refraining from waiting for receipt of a message M2.
[0069] In one example, the message M2 in arranged to include a
previous-exchange indication to indicate whether the timing
measurement information relates to a current or a previous ToF
message exchange between the responding station and the initiating
station.
[0070] In one example, when the previous-exchange indication
indicates that the timing measurement information relates to the
current ToF exchange, the method further includes the initiating
station calculating a ToF using a t1 value and a t4 value from the
current exchange and the timing measurement information received in
the message M2, when the previous-exchange indication indicates
that the timing measurement information relates to a previous ToF
exchange, the method further includes the initiating station
calculating a ToF using the t1 value and the t4 value from a
previous exchange and the timing measurement information received
in the message M2, the t1 value is a time-stamp associated with
transmission of message M1 by the initiating station and the t4
value is a time-stamp associated with receipt of the
acknowledgement frame that acknowledges receipt of the message
M1.
[0071] In one example, the previous-exchange indication comprises a
one-bit flag.
[0072] In one example, the message M1 is arranged to further
include a dialog token that indicates a specific instance of a
timing measurement action frame, and the previous-exchange
indication comprises the dialog token from the specific instance of
a timing measurement action frame from which the timing measurement
information that is included in the message M2 had been
determined.
[0073] In one example, when the message M2 includes a dialog token
indicating a specific instance of a prior message M1, the method
includes the initiating station calculating a ToF using a (t4-t1)
value corresponding to the specific instance of the message M1
indicated in the dialog token.
[0074] In one example, when the more PPDU indication in the HTC
field carried by the ACK frame is set to one, the more PPDU
indication indicates that that a PPDU will follow the ACK frame
after a short-interframe space (SIFS), the PPDU that is to follow
being included in the message M2.
[0075] In one example, when the ACK frame includes the HTC field,
the ACK frame is contained in a control wrapper frame.
[0076] In one example, when the message M2 is an Action No ACK
management frame, the method includes refraining, by the initiating
station, from sending an ACK frame to acknowledge the message
M2.
[0077] In one example, when the message M2 is an Action No ACK
management frame, the message M2 is arranged to include the timing
measurement information from both a current ToF message exchange
and a previous ToF message exchange.
[0078] In one example, the ACK frame and the message M2 comprise a
single aggregated media-access-control protocol data unit
(A-MPDU).
[0079] In one example, the initiating station configuring the
message M1 to further include timing measurement information and a
dialog token related to the included timing measurement
information, the dialog token indicating a ToF message exchange
which the timing measurement information is associated.
[0080] In one example, a communication station is arranged to
perform time-of-flight (ToF) positioning, the station comprising
physical layer circuitry and processing elements to: transmit a
message M1 carrying a high-throughput control (HTC) field, the HTC
field including a reverse direction grant (RDG) indication, the RDG
indication granting permission to a responding station to send
information hack to the initiating station, the message M1 being a
timing, measurement action frame: receive an acknowledgement (ACK)
frame to acknowledge receipt of the message M1, the ACK frame
carrying an HTC field that includes an indication to indicate
whether a separate frame is to follow the ACK frame; and receive a
message M2 from the responding station, the message M2 including
timing measurement information from either a current or a previous
ToF message exchange.
[0081] In one example, the indication in the HTC field of the ACK
frame is a more physical-layer convergence protocol (PLCP) data
unit (PPDU) indication, when the indication in the HTC field of the
ACK frame indicates that a PPDU is to follow, the message M2
comprises the PPDU and the initiating station is arranged to wait
for receipt of the message M2.
[0082] In one example, the message M2 in arranged to include a
previous-exchange indication to indicate whether the timing
measurement information relates to a current or a previous ToF
message exchange between the responding station and the initiating
station.
[0083] In one example, when the message M2 is an Action No ACK
management frame, the initiating station is arranged to refrain
from sending an ACK frame to acknowledge the message M2 and the
message M2 is arranged to include the timing measurement
information from both a current ToF message exchange and a previous
ToF message exchange. In one example, the ACK frame and the message
M2 comprise a single aggregated media-access-control protocol data
unit (A-MPDU).
[0084] In one example, a method for positioning comprising:
transmitting a first timing measurement action frame carrying a
high-throughput control (HTC) field, the HTC field including a
reverse direction grant (RDG) indication, the RDG indication
granting permission to a responding station to send information
back to an initiating station; and receiving a second timing
measurement action frame from the responding station when an HTC
field in an acknowledgement (ACK) frame indicates that a separate
frame is to follow the ACK frame, the second timing measurement
action frame including tinting measurement information from at
least at one of a current and a previous message exchange.
[0085] In one example, when the second timing measurement action
frame is an Action No ACK management frame, the second timing
measurement action frame is arranged to include the timing
measurement information from both a current time-of-flight (Ton
message exchange and at least one previous ToF message
exchange.
[0086] In one example, when the second timing measurement action
frame is an Action No ACK management frame, the method includes
refraining, by the initiating station, from sending an ACK frame to
acknowledge the second timing measurement action frame.
[0087] In one example, the ACK frame and the second timing
measurement action frame comprise an aggregated
media-access-control protocol data unit (A-MPDU), the ACK frame to
acknowledge receipt of the first timing measurement action frame
prior to receiving the second timing measurement action frame.
[0088] In one example, the second timing measurement action frame
includes a previous-exchange indication to indicate whether the
timing measurement information relates to a current or a previous
ToF message exchange between the responding station and the
initiating station.
[0089] In one example, the ACK frame carries an HTC field that
includes an indication to indicate whether a separate frame is to
follow the ACK frame, the separate frame being second timing
measurement action frame.
[0090] In one example, a non-transitory computer-readable storage
medium that stores instructions for execution by one or more
processors to perform operations comprising: transmitting a first
timing measurement action frame carrying a high-throughput control
(HTC) field, the HTC field including a reverse direction grant
(RDG) indication, the RDG indication granting permission to a
responding station to send information back to an initiating
station; and receiving a second timing measurement action frame
from the responding station when an HTC field in an acknowledgement
(ACK) frame indicates that a separate frame is to follow the ACK
frame the second timing measurement action frame including timing
measurement information from at least at one of a current and a
previous message exchange.
[0091] In one example, when the second timing measurement action
frame is an Action No ACK management frame, the second timing
measurement action frame is arranged to include the timing
measurement information from both a current time-of-flight (ToF)
message exchange and at least one previous ToF message
exchange.
[0092] In one example, the ACK frame and the second timing
measurement action frame comprise an aggregated
media-access-control protocol data unit (A-MPDU), the ACK frame to
acknowledge receipt of the first timing measurement action frame
prior to receiving the second timing measurement action frame, and
the second timing measurement action frame includes a
previous-exchange indication to indicate whether the timing
measurement information relates to a current or a previous ToF
message exchange between the responding station and the initiating
station.
[0093] The Abstract is provided to comply with 37 C.F.R. Section
1.72(b) requiring an abstract that will allow the reader to
ascertain the nature and gist of the technical disclosure. It is
submitted with the understanding that it will not be used to limit
or interpret the scope or meaning of the claims. The following
claims are hereby incorporated into the detailed description, with
each claim standing on its own as a separate embodiment.
* * * * *