U.S. patent application number 14/730822 was filed with the patent office on 2015-09-24 for limiting wireless discovery range.
The applicant listed for this patent is Qualcomm Incorporated. Invention is credited to Santosh Paul Abraham, George Cherian, Rolf De Vegt, Simone Merlin, Alireza Raissinia, Hemanth Sampath, Vinay Sridhara.
Application Number | 20150271759 14/730822 |
Document ID | / |
Family ID | 47989401 |
Filed Date | 2015-09-24 |
United States Patent
Application |
20150271759 |
Kind Code |
A1 |
Abraham; Santosh Paul ; et
al. |
September 24, 2015 |
LIMITING WIRELESS DISCOVERY RANGE
Abstract
Systems and methods of limiting wireless discovery range are
described. A method may include determining, at a first device, a
discovery range threshold that limits a distance from the first
device at which a second device is operative to decode a discovery
message. The method may include adjusting a transmission attribute
at the first device based on the discovery range threshold. The
method may include sending the discovery message in accordance with
the adjusted transmission attribute.
Inventors: |
Abraham; Santosh Paul; (San
Diego, CA) ; Cherian; George; (San Diego, CA)
; Sampath; Hemanth; (San Diego, CA) ; De Vegt;
Rolf; (San Francisco, CA) ; Merlin; Simone;
(San Diego, CA) ; Raissinia; Alireza; (Monte
Sereno, CA) ; Sridhara; Vinay; (Santa Clara,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Qualcomm Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
47989401 |
Appl. No.: |
14/730822 |
Filed: |
June 4, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13763521 |
Feb 8, 2013 |
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14730822 |
|
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61610320 |
Mar 13, 2012 |
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Current U.S.
Class: |
455/41.2 |
Current CPC
Class: |
H04W 28/021 20130101;
H04W 64/006 20130101; H04W 48/12 20130101; H04W 84/18 20130101;
H04W 8/005 20130101; H04W 52/04 20130101 |
International
Class: |
H04W 52/04 20060101
H04W052/04; H04W 48/12 20060101 H04W048/12; H04W 28/02 20060101
H04W028/02; H04W 64/00 20060101 H04W064/00 |
Claims
1. A method comprising: determining, at a first device, a discovery
range threshold that limits a distance from the first device at
which a second device is operative to decode a discovery message;
adjusting a transmission attribute at the first device based on the
discovery range threshold; and sending the discovery message in
accordance with the adjusted transmission attribute.
2. The method of claim 1, wherein the transmission attribute
includes a transmit power level, a modulation and coding scheme
(MCS), or any combination thereof.
3. The method of claim 1, wherein the discovery message is included
in an information element of an Institute of Electrical and
Electronics Engineers (IEEE) 802.11 beacon.
4. The method of claim 1, wherein the discovery message is included
in a management action frame.
5. The method of claim 1, further comprising encoding information
to be displayed by the second device into the discovery
message.
6. The method of claim 1, further comprising encoding a uniform
resource locator (URL) to be navigated to by the second device into
the discovery message.
7. The method of claim 1, wherein determining the discovery range
threshold at the first device includes receiving data indicating
the discovery range threshold from a device other than the first
device.
8. An apparatus comprising: a processor; and a memory storing
instructions executable by the processor to: determine, at a first
device, a discovery range threshold that limits a distance from the
first device at which a second device is operative to decode a
discovery message; adjust a transmission attribute at the first
device based on the discovery range threshold; and send the
discovery message in accordance with the adjusted transmission
attribute.
9. The apparatus of claim 8, wherein the first device comprises a
wireless local area network (WLAN) device, an access point, or any
combination thereof.
10. The apparatus of claim 8, wherein the transmission attribute
includes a transmit power level, a modulation and coding scheme
(MCS), or any combination thereof.
11. The apparatus of claim 8, wherein the discovery message is
included in an information element of an Institute of Electrical
and Electronics Engineers (IEEE) 802.11 beacon.
12. The apparatus of claim 8, wherein the discovery message is
included in a management action frame.
13. The apparatus of claim 8, wherein the instructions are further
executable by the processor to encode, into the discovery message,
information to be displayed by the second device.
14. The apparatus of claim 8, wherein the instructions are further
executable by the processor to encode, into the discovery message,
a uniform resource locator (URL) to be navigated to by the second
device.
15. A method comprising: receiving at a second device a discovery
message from a first device; determining a distance between the
second device and the first device based on at least one attribute
of the discovery message; based on determining that the distance is
within a discovery range threshold, processing the discovery
message; and based on determining that the distance is outside the
discovery range threshold, discarding the discovery message.
16. The method of claim 15, wherein the at least one attribute of
the discovery message includes a received signal strength
indication (RSSI).
17. The method of claim 16, wherein determining the distance
comprises searching a table that associates RSSI values with
expected distances.
18. The method of claim 17, further comprising storing the table at
the second device.
19. The method of claim 15, wherein the at least one attribute of
the discovery message includes a transmit power, and wherein the
discovery message includes an indicator of the transmit power.
20. The method of claim 15, wherein the at least one attribute of
the discovery message includes a modulation and coding scheme
(MCS).
21. The method of claim 15, wherein the discovery range threshold
is included in the discovery message.
22. The method of claim 15, further comprising, when the distance
is within the discovery range threshold, displaying at least a
portion of the processed discovery message at the second
device.
23. The method of claim 15, further comprising, when the distance
is within the discovery range threshold, navigating to a uniform
resource locator (URL) in the processed discovery message via an
application executed at the second device.
24. An apparatus comprising: a processor; and a memory storing
instructions executable by the processor to: receive at a second
device a discovery message from a first device; determine a
distance between the second device and the first device based on at
least one attribute of the discovery message; based on determining
that the distance is within a discovery range threshold, process
the discovery message; and based on determining that the distance
is outside the discovery range threshold, discard the discovery
message.
25. The apparatus of claim 24, wherein the at least one attribute
of the discovery message includes a received signal strength
indication (RSSI).
26. The apparatus of claim 25, further comprising a table that
associates RSSI values with expected distances and that is stored
at the second device.
27. The apparatus of claim 26, wherein the instructions are
executable by the processor to determine the distance by searching
the table.
28. The apparatus of claim 24, wherein the at least one attribute
of the discovery message includes a transmit power, and wherein the
discovery message includes an indicator of the transmit power.
29. The apparatus of claim 24, wherein the discovery range
threshold is included in the discovery message.
30. The apparatus of claim 24, wherein the second device comprises
a mobile telephone, a portable computing device, a tablet computing
device, a personal digital assistant (PDA), a portable media
player, or any combination thereof.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a divisional application of and
claims priority to commonly owned U.S. patent application Ser. No.
13/763,521 filed Feb. 8, 2013, which claims priority from commonly
owned U.S. Provisional Patent Application No. 61/610,320 filed Mar.
13, 2012, the contents of both of which are expressly incorporated
herein by reference in their entirety.
BACKGROUND
[0002] 1. Field
[0003] The present disclosure relates to discovery messages in
wireless networks.
[0004] 2. Background
[0005] Advances in technology have resulted in smaller and more
powerful computing devices. For example, there currently exist a
variety of portable personal computing devices, including wireless
computing devices, such as portable wireless telephones, personal
digital assistants (PDAs), and paging devices that are small,
lightweight, and easily carried by users. More specifically,
portable wireless telephones, such as cellular telephones and
Internet Protocol (IP) telephones, can communicate voice and data
packets over wireless networks. Many such wireless telephones
incorporate additional devices to provide enhanced functionality
for end users. For example, a wireless telephone can also include a
digital still camera, a digital video camera, a digital recorder,
and an audio file player. Also, such wireless telephones can
execute software applications, such as a web browser application
that can be used to access the Internet. As such, these wireless
telephones can include significant computing capabilities.
[0006] In some communication systems, communications networks may
be used to exchange messages among several interacting
spatially-separated devices. Networks may be classified according
to geographic scope, which could be, for example, a metropolitan
area, a local area, or a personal area. Such networks may be
designated respectively as a wide area network (WAN), a
metropolitan area network (MAN), a local area network (LAN), a
wireless local area network (WLAN), or a personal area network
(PAN). Networks may also differ according to the switching/routing
techniques used to interconnect the various network nodes and
devices (e.g., circuit switching vs. packet switching), the type of
physical media employed for transmission (e.g., wired vs.
wireless), and the set of communication protocols used (e.g.,
Internet protocol suite, SONET (Synchronous Optical Networking),
Ethernet, etc.).
[0007] Wireless networks may be preferred when network elements are
mobile and have dynamic connectivity needs or if the network
architecture is formed in an ad hoc, rather than fixed, topology.
Wireless networks may employ intangible physical media in an
unguided propagation mode using electromagnetic waves in the radio,
microwave, infra-red, optical, or other frequency bands. Wireless
networks may advantageously facilitate user mobility and rapid
field deployment when compared to fixed wired networks.
[0008] Devices in a wireless network may transmit/receive
information between each other. The information may include
packets. The packets may include overhead information (e.g., header
information, packet properties, etc. that helps in routing the
packets through the network) as well as data (e.g., user data,
multimedia content, etc. in a payload of the packet). One type of
packet, called a discovery packet, may be used to introduce two
different devices communicating via a medium that is shared by
multiple devices.
SUMMARY
[0009] Wireless networks are typically used as an access medium.
For example, most wireless networks include an access point that
facilitates communication between locally connected devices and an
external network, such as the Internet. Nevertheless, as wireless
devices become more common, networks may be formed for reasons
other than to provide access to an external network. For example,
when numerous wireless devices coexist in a fixed space (e.g., a
stadium or a classroom), it may be useful for the wireless devices
to communicate directly to each other (e.g., to share messages,
multimedia, etc.). This type of ad hoc localized wireless
networking may be referred to as "social Wi-Fi." However, the
coexistence of many wireless devices in a relatively small area may
lead to medium congestion. For example, consider two adjacent
classrooms in a school, where each classroom attempts to form its
own social Wi-Fi network. Devices operating in one classroom may
conflict or interfere with devices operating in the other
classroom. In such a situation, it may be beneficial to predicate
wireless discovery on inter-device distance, so that students in
one classroom can communicate with each other without detecting
messages between students in the other classroom.
[0010] Systems and methods of limiting wireless discovery range are
disclosed. A device sending a discovery message may limit decoding
of the discovery message to a receiving device that is within a
particular discovery range threshold. When a wireless discovery
range is limited, the discovery message may be considered "range
adapted." For example, a device may adjust a transmit power and/or
a modulation and coding scheme (MCS) of an outgoing discovery
message such that the message is not (or cannot be) decoded outside
the discovery range threshold. A receiving device may range adapt a
discovery message by decoding or discarding the discovery message
based on how far the receiving device is from the transmitting
device. Decoding a discovery message may trigger additional actions
at the receiving device, such as displaying data or navigating to a
uniform resource locator (URL).
[0011] The techniques described herein may utilize various metrics
to determine or estimate the distance between two devices,
including, but not limited to, transmit power, MCS, received signal
strength indication (RSSI), time elapsed between sending a range
determination message (e.g., a request-to-send (RTS) message) and
receiving a range determination response (e.g., a clear-to-send
(CTS) message), and a location request/response exchange.
[0012] In a heterogeneous network that supports communication of
both range adapted and range independent discovery messages, each
discovery message may include a range adaptation bit indicating
whether range adaptation is to be performed by a receiving device.
Range adapted discovery messages may also include the corresponding
discovery range threshold to be used by the receiving device in
determining whether to decode or discard the discovery message.
[0013] In a particular embodiment, a method includes adjusting a
transmission attribute at a first device based on a discovery range
threshold. In response to sending a discovery message from the
first device in accordance with the adjusted transmission
attribute, a second device at a distance within the discovery range
threshold decodes the discovery message and a third device at a
distance outside the discovery range threshold discards or fails to
decode the discovery message.
[0014] In another particular embodiment, a method includes
determining, at a first device, a discovery range threshold that
limits a distance from the first device at which a second device is
operative to decode a discovery message. The method also includes
adjusting a transmission attribute at the first device based on the
discovery range threshold and sending the discovery message in
accordance with the adjusted transmission attribute.
[0015] In another particular embodiment, an apparatus includes a
processor and a memory storing instructions executable by the
processor to receive at a second device a discovery message sent
from a first device. The instructions are also executable by the
processor to determine a distance between the second device and the
first device based on at least one attribute of the discovery
message. The instructions are further executable by the processor
to decode the discovery message when the distance is within a
discovery range threshold and to discard the discovery message when
the distance is outside the discovery range threshold.
[0016] In another particular embodiment, an apparatus includes a
processor and a memory storing instructions executable by the
processor to send a range determination message from a first device
to a second device and to receive a range determination response at
the first device from the second device. The instructions are also
executable by the processor to determine a distance between the
first device and the second device based on an elapsed time between
the sending of the range determination message and the receiving of
the range determination response. The instructions are further
executable by the processor to send a discovery message from the
first device to the second device in response to determining that
the distance is within a discovery range threshold.
[0017] In another particular embodiment, a method includes sending
a range determination message to a first device from a second
device and receiving at the second device a range determination
response from the first device. The method also includes
determining a distance between the second device and the first
device based on an elapsed time between the sending of the range
determination message and the receiving of the range determination
response. The method includes decoding a discovery message received
from the first device when the distance is within a discovery range
threshold and discarding the discovery message received from the
first device when the distance is outside the discovery range
threshold.
[0018] In another particular embodiment, a method includes sending
a discovery message from a first device to a second device. The
discovery message includes data indicating whether a range
determination mechanism is to be used to determine whether to
perform an action (e.g., connection setup) in response to the
discovery message.
[0019] In another particular embodiment, a method includes
receiving a discovery message from a first device at a second
device, where the discovery message includes a range adaptation
indicator bit. The method also includes decoding the discovery
message when the range adaptation bit has a first value. The method
includes, when the range adaptation bit has a second value,
selectively decoding or discarding the discovery message based on
whether a distance between the second device and the first device
is within a discovery range threshold included in or defined by the
discovery message.
[0020] In another particular embodiment, a method includes
receiving a discovery message from a first device at a second
device. The method also includes sending a request for a location
of the first device and receiving a response indicating the
location of the first device. The method further includes
determining a distance between the second device and the first
device based on the location of the first device. The method
includes selectively decoding or discarding the discovery message
based on whether the distance is within a discovery range
threshold.
[0021] In another particular embodiment, a method includes
receiving a message (e.g., a discovery message or a query message)
from a first device at a second device and executing a first range
determination mechanism in response to determining that the message
indicates that range determination is to be performed. The method
also includes discarding the message when a result of the first
range determination mechanism indicates that the first device and
the second device are separated by a distance that is greater than
or equal to a first range threshold. The method further includes
executing a second range determination mechanism when the result of
the first range determination mechanism indicates that the first
device and the second device are separated by a distance that is
less than the first range threshold. The method includes
selectively discarding the message or performing at least one
action in response to the message based on a result of the second
range determination mechanism.
[0022] One particular advantage provided by at least one of the
disclosed embodiments is an ability of transmitting devices and
receiving devices to individually limit wireless communication
discovery range.
[0023] Other aspects, advantages, and features of the present
disclosure will become apparent after review of the entire
application, including the following sections: Brief Description of
the Drawings, Detailed Description, and the Claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a diagram of a particular embodiment of a system
that is operable to limit wireless discovery range;
[0025] FIG. 2 is a diagram to illustrate an example of limiting
wireless discovery range in a particular environment;
[0026] FIG. 3 is a flowchart of a particular embodiment of a method
of limiting wireless discovery range at a transmitting device by
adjusting a transmission attribute;
[0027] FIG. 4 is a flowchart of another particular embodiment of a
method of limiting wireless discovery range at a transmitting
device by adjusting a transmission attribute;
[0028] FIG. 5 is a flowchart of a particular embodiment of a method
of limiting wireless discovery range at a receiving device based on
an attribute of a received message;
[0029] FIG. 6 is a flowchart of a particular embodiment of a method
of limiting wireless discovery range at a device based on time
elapsed between sending a RTS message and receiving a CTS
message;
[0030] FIG. 7 is a flowchart of another particular embodiment of a
method of limiting wireless discovery range at a device based on
time elapsed between sending a RTS message and receiving a CTS
message;
[0031] FIG. 8 is a flowchart of a particular embodiment of a method
of operating a wireless device;
[0032] FIG. 9 is a block diagram of a mobile communication device
including components that are operable to limit wireless discovery
range;
[0033] FIG. 10 illustrates a discovery frame 1001 that includes one
or more discovery type-length-values (TLVs); and
[0034] FIG. 11 illustrates an alternate embodiment of a discovery
frame.
DETAILED DESCRIPTION
[0035] FIG. 1 is a diagram of a particular embodiment of a system
100 that is operable to limit wireless discovery range. The system
100 may include a first device 110 and a second device 120
separated by a distance 102.
[0036] In a particular embodiment, the first device 110 may be a
WLAN device, an access point (AP), or any combination thereof. The
second device 120 may be a mobile device, such as a mobile
telephone, a portable computing device, a tablet computing device,
a personal digital assistant (PDA), a portable media player, or any
combination thereof.
[0037] The first device 110 may include a transmitter 111 and a
receiver 116. Although illustrated in FIG. 1 as single blocks, the
transmitter 111 and the receiver 116 may each represent various
hardware and/or software components used in transmitting and
receiving wireless messages. The transmitter 111 may be configured
to vary one or more transmission attributes of outgoing messages.
For example, the transmitter 111 may vary transmit power and MCS
for particular messages, such as a discovery message 130, a range
determination message (e.g., an illustrative RTS message 142), and
a range determination response (e.g., an illustrative CTS message
154). In a particular embodiment, the transmitter 111 and the
receiver 116 may be integrated (e.g., into a transceiver).
[0038] The first device 110 may also include an encoder 112
configured to encode the discovery message 130 and a timer 113
(e.g., a hardware timer or a software timer). In a particular
embodiment, the first device 110 may store a discovery range
threshold 114. The discovery range threshold 114 may represent a
distance outside of which devices receiving the discovery message
130 (e.g., the second device 120) will not or cannot decode the
discovery message 130 (or at least a portion thereof). In a
particular embodiment, the discovery message 130 may be an
Institute of Electrical and Electronics Engineers (IEEE) beacon (or
an information element (IE) thereof) or a management action frame
that is broadcast periodically (e.g., every 100 milliseconds). Data
encoded into the discovery message 130 may include displayable
information 131 and/or a URL 132. When the discovery message 130 is
decoded, the displayable information 131 may be automatically
displayed by the decoding device and the URL 132 may be
automatically navigated to by the decoding device.
[0039] In a particular embodiment, the discovery message 130 may
also include a range adaptation (RA) bit 133. The range adaptation
bit 133 may indicate whether or not range adaptation is to be
performed for the discovery message 130. Thus, the range adaptation
bit 133 may indicate whether the second device 120 is to decode the
discovery message 130 from the first device 110 independent of
whether the inter-device distance 102 between the first device 110
and the second device 120 is within the discovery range threshold
114. When the range adaptation bit 133 has a first value (e.g.,
zero), the discovery message 130 may be a range independent
discovery message that is always decoded. When the range adaptation
bit 133 has a second value (e.g., one), the discovery message 130
may be a range adapted discovery message that is selectively
decoded or discarded based on whether the distance 102 is within
the discovery range threshold 114. In a particular embodiment, the
first device 110 may include the discovery range threshold 114 in
the discovery message 130, as shown.
[0040] The second device 120 may include a transmitter 126 and a
receiver 121. Although illustrated in FIG. 1 as single blocks, the
transmitter 126 and the receiver 121 may each represent various
hardware and/or software components used in transmitting and
receiving wireless messages. The receiver 121 may be configured to
measure one or more attributes of incoming messages. For example,
the receiver 121 may measure a received signal strength indication
(RSSI) of the discovery message 130. The transmitter 126 may be
operable to send one or more messages to the first device 110, such
as a range determination response (e.g., an illustrative CTS
message 144) and a range determination message (e.g., an
illustrative RTS message 152). In a particular embodiment, the
transmitter 126 and the receiver 121 may be integrated (e.g., into
a transceiver).
[0041] The second device 120 may also include a decoder 122
configured to decode the discovery message 130 and a timer 124
(e.g., a hardware timer or a software timer). The second device 120
may also include one or more applications, such as a browser
application 123. In a particular embodiment, the browser
application 123 may be used to navigate to the URL 132 included in
the discovery message 130.
[0042] In one embodiment of operation, the first device 110 may
limit wireless discovery range by varying a transmission attribute
of the discovery message 130. For example, the first device 110 may
elect to limit discovery range to the discovery range threshold 114
(e.g., 3 feet). The discovery range threshold 114 may be set by the
first device 110 or may be received from an external device (e.g.,
in a programming message). The transmitter 111 may adjust a
transmit power and/or a MCS of the discovery message 130 based on
the discovery range threshold 114. The adjusted transmit power
and/or MCS may operate to limit decodability of the discovery
message 130 outside the discovery range threshold 114. Thus, if the
distance 102 is within the discovery range threshold 114 (e.g.,
less than or equal to 3 feet), the second device 120 may decode the
discovery message 130. Conversely, if the distance 102 is outside
the discovery range threshold 114 (e.g., greater than 3 feet), the
second device 120 may discard or fail to decode the discovery
message 130.
[0043] Alternately, the first device 110 may limit wireless
discovery range by using the timer 113 to measure the distance 102.
For example, the first device 110 may send a range determination
message (e.g., the RTS message 142) to the second device 120 and
may receive a range determination response (e.g., the CTS message
144), in accordance with an underlying wireless protocol (e.g., an
IEEE 802.11 protocol). The timer 113 may be started upon sending
the RTS message 142 and may be stopped upon receiving the CTS
message 144. Based on the time elapsed, the first device 110 may
estimate the distance 102. If the distance 102 is within the
discovery range threshold 114, the first device 110 may send the
discovery message 130 to the second device 120. The first device
110 may refrain from sending the discovery message 130 to the
second device 120 if the distance 102 is outside the discovery
range threshold 114. It should be noted that the use of RTS and CTS
messages for range determination is provided for illustration only.
Selected embodiments may use messages other than RTS and CTS
messages. For example, a different message that solicits a response
within a fixed interval of time to determine distance may be used.
Additional examples of range determination messages and responses
are further described herein.
[0044] When the transmit power or MCS of the discovery message 130
results in the second device 120 being unable to decode the
discovery message 130, the second device 120 may discard the
discovery message. However, in heterogeneous networks that include
both range adapted and range independent discovery messages,
varying transmission attributes of individual devices may be
complex. In another embodiment of operation, the second device 120
may limit wireless discovery range based on attribute(s) of the
received discovery message 130, even if the discovery message 130
is otherwise decodable. For example, the receiver 121 may measure a
RSSI of the discovery message 130 and may determine the distance
102 based on the RSSI. In a particular embodiment, the distance 102
may be determined by searching for the determined RSSI in a table
125 stored at the second device 120, where the table 125 associates
RSSI values to expected distances. The values in the table 125 may
be specified by an industry standard, such as an IEEE standard.
When the distance 102 is within the discovery range threshold 114,
the decoder 122 may decode the discovery message 130. When the
distance 102 is outside the discovery range threshold 114, the
discovery message 130 may be discarded. The second device 120 may
also range adapt the discovery message 130 based on a transmit
power indicator included in the discovery message 130 and/or based
on the MCS of the discovery message 130.
[0045] Alternately, the second device 120 may limit wireless
discovery range by using the timer 124 to measure the distance 102.
For example, the second device 120 may send the RTS message 152 to
the first device 110 and may receive the CTS message 154 in
response. The timer 124 may be started upon sending the RTS message
152 and may be stopped upon receiving the CTS message 154. Based on
the time elapsed, the second device 120 may estimate the distance
102. If the distance 102 is within the discovery range threshold
114, the second device 120 may decode the discovery message 130.
Otherwise, the second device 120 may discard the discovery message
130. It should be noted that the discovery message 130 may have
been received by the second device 120 prior to sending the RTS
message 152 or may be received after having received the CTS
message 154.
[0046] When operating in a heterogeneous network, the second device
120 may treat each discovery message 130 independently. When the
range adaptation bit indicates that the discovery message 130 is
range independent, the second device 120 may decode the discovery
message 130 independent of whether its distance from the first
device 110 is within the discovery range threshold 114. When the
range adaptation bit indicates that the discovery message 130 is
range adapted, the second device 120 may selectively decode or
discard the discovery message 130 based on whether or not its
distance from the first device 110 is less than the discovery range
threshold 114.
[0047] In a particular embodiment, the distance 102 may be stored
at the first device 110 and/or the second device 120 for use in
subsequent range adaptation operations. Alternately, or in
addition, the distance 102 may be recalculated periodically or in
response to detecting movement of the first device 110 and/or the
second device 120.
[0048] In a particular embodiment, the system 100 of FIG. 1 may
support range determination mechanisms other than RTS/CTS message
exchange. To illustrate, a location request/response exchange may
be used. In response to receiving a location request from a first
device, a second device may determine and/or transmit its location
to the first device. For example, the second device may determine
its location via a global positioning system (GPS) module or
transceiver included within or otherwise accessible to the second
device. Alternately, the first device may request the location of
the second device from a third device (e.g., a location database).
In yet another example, the second device may request its location
from the third device and may forward the received location to the
first device.
[0049] In a particular embodiment, before or after receiving the
discovery message 130, the second device 120 may request a location
of the first device 110 and may receive a response indicating the
location of the first device 110. The second device 120 may
determine the distance 102 based on the location of the first
device 110 and may selectively decode or discard the discovery
message 130 based on whether the distance 102 is within the
discovery range threshold 114. In another particular embodiment,
the first device 110 may request the location of the second device
120 and may condition sending of the discovery message 130 to the
second device 120 based on whether the location of the second
device 120 is within the discovery range threshold 114.
[0050] The system 100 of FIG. 1 may thus enable limiting wireless
discovery range by both transmitting devices (e.g., the first
device 110) as well as receiving devices (e.g., the second device
120). The system 100 may also support heterogeneous networks in
which some discovery message are range limited while other
discovery messages are range independent. In addition, by packaging
actionable data (e.g., the information 131 or the URL 132) into the
discovery message 130 instead of into a subsequent data message,
the system 100 may leverage the discovery message 130 to introduce
devices as well as communicate data between devices. This may
enable simpler and faster data transfers than existing wireless
methods, which may involve complex handshake and security processes
after discovery and prior to data exchange. Selective range
adaptation may also enable user-friendly range-aware wireless
services, as further described with reference to FIG. 2.
[0051] FIG. 2 is a diagram to illustrate a particular example of
limiting wireless discovery range in a museum environment 200. It
should be noted that the museum environment 200 is for illustration
only. Limiting wireless discovery range in accordance with the
techniques described herein may be performed in various other
environments.
[0052] As illustrated in FIG. 2, the museum environment 200
includes a museum cafe and a gallery that has various paintings on
display. The museum cafe includes a wireless transmitter 202
(designated "MC"). The wireless transmitter 202 may transmit
discovery messages that are range independent (e.g., have a range
adaptation bit set to zero) and that include information associated
with the museum cafe (e.g., daily specials or a URL of a cafe
menu). Each of the paintings (designated "P1" to "P9") may also
have associated wireless transmitters. In contrast to the wireless
transmitter 202 of the museum cafe, the discovery messages
transmitted by the painting transmitters may be range adapted. For
example, each of the discovery messages transmitted by the painting
transmitters may have a range adaptation bit set to one and may
include a corresponding discovery range threshold. To illustrate,
the discovery range threshold for the painting "P4" is indicated in
FIG. 2, at 204. It should be noted that different paintings may
have different discovery range thresholds. For example, as shown in
FIG. 2, the discovery range threshold for the painting "P2" is
larger than the discovery range thresholds for the other
paintings.
[0053] As a museum patron walks around the museum environment 200,
a wireless device (e.g., mobile phone) of the patron may display
range-aware information. For example, the patron may download and
execute a museum tour application on the wireless device. Depending
on where the patron is located, the patron's wireless device may
receive discovery messages from various transmitters. The museum
tour application on the wireless device may selectively decode or
discard discovery messages as described with reference to FIG.
1.
[0054] For example, when the patron is at a first location 210, the
patron's wireless device may decode the discovery message from the
wireless transmitter 202 and may display cafe specials. Discovery
messages received from any of the painting transmitters may be
discarded because the first location 210 is not within any of the
corresponding discovery range thresholds of the paintings. When the
patron is at a second location 220, the patron's wireless device
may display the cafe specials and information for the painting P1.
When the patron is in a third location 230, the patron's wireless
device may display the cafe specials, information for the painting
P2, and information for the painting P7. When multiple patrons and
wireless devices are in the museum environment 200, each patron's
wireless device may display selected information based on where
that patron is located. Thus, the same discovery message may be
decoded by one wireless device (e.g., that is within the
corresponding discovery range threshold) but discarded by another
wireless device (e.g., that is outside the corresponding discovery
range threshold).
[0055] Limiting wireless discovery range as described herein may
thus enable user-friendly range-aware wireless services, such as
the museum information service described with reference to FIG. 2.
Notably, such services may be implemented without the use of
dedicated access points that facilitate device-to-device
communication and Internet access. Instead, each transmitter (e.g.,
the museum cafe transmitter 202 and the painting transmitters) may
serve as an access point for an ad-hoc wireless network whose
membership may be restricted by distance from the transmitter.
[0056] FIG. 3 is a flowchart of a particular embodiment of a method
300 of limiting wireless discovery range at a transmitting device
by adjusting a transmission attribute. In an illustrative
embodiment, the method 300 may be performed by the first device 110
of FIG. 1.
[0057] The method 300 may include determining a discovery range
threshold at a first device, at 302. For example, in FIG. 1, the
first device 110 may determine the discovery range threshold 114.
The method 300 may also include adjusting a transmission attribute
at the first device based on the discovery range threshold, at 304.
The transmission attribute may be adjusted such that in response to
sending a discovery message from the first device in accordance
with the adjusted transmission attribute, a second device at a
distance within the discovery range threshold decodes the discovery
message. A third device at a distance outside the discovery range
threshold discards the discovery message. For example, in FIG. 1,
the first device 110 may adjust a transmission attribute (e.g.,
transmit power or MCS) of the discovery message 130 based on the
discovery range threshold 114. When the distance 102 between the
first device 110 and the second device 120 is within the discovery
range threshold 114, the second device 120 may decode the discovery
message 130. When the distance 102 is outside the discovery range
threshold 114, the second device 120 (and/or a different third
device not shown in FIG. 1) may discard the discovery message
130.
[0058] FIG. 4 is a flowchart of another particular embodiment of a
method 400 of limiting wireless discovery range at a transmitting
device by adjusting a transmission attribute. In an illustrative
embodiment, the method 400 may be performed by the first device 110
of FIG. 1.
[0059] The method 400 may include determining, at a first device, a
discovery range threshold that limits a distance from the first
device at which a second device is operative to decode a discovery
message, at 402. The discovery message may be an IEEE 802.11 beacon
or a management action frame. For example, in FIG. 1, the first
device 110 may determine the discovery range threshold 114.
[0060] The method 400 may also include adjusting a transmission
attribute (e.g., transmit power and/or MCS) at the first device
based on the discovery range threshold, at 404. The method 400 may
further include encoding information to be displayed by the second
device or a URL to be navigated to by the second device into the
discovery message, at 406. For example, in FIG. 1, the encoder 112
may encode the displayable information 131 or the URL 132 into the
discovery message 130.
[0061] The method 400 may include sending the discovery message in
accordance with the adjusted transmission attribute, at 408. For
example, in FIG. 1, the transmitter 111 may send (e.g., broadcast)
the discovery message 130 using a transmit power level adjusted so
that devices outside the discovery range threshold 114 do not
decode the broadcast discovery message 130.
[0062] FIG. 5 is a flowchart of a particular embodiment of a method
500 of limiting wireless discovery range at a receiving device
based on an attribute of a received message. In an illustrative
embodiment, the method 500 may be performed by the second device
120 of FIG. 1.
[0063] The method 500 may include receiving a discovery message
from a first device at a second device, at 502. For example, in
FIG. 1, the second device 120 may receive the discovery message 130
from the first device 110.
[0064] The method 500 may include determining a distance between
the second device and the first device based on one or more
attributes of the discovery message. To illustrate, a first
implementation may include determining a RSSI of the discovery
message, at 504, and determining the distance based on the RSSI, at
506. The distance may be determined by searching for the RSSI in a
table stored at the second device. For example, in FIG. 1, the
second device 120 may determine the distance 102 by searching the
table 125. A second implementation may include determining a
transmit power of the discovery message from a transmit power
indicator in the discovery message, at 508, and determining the
distance based on the transmit power, at 510. A third
implementation may include determining a MCS of the discovery
message, at 512, and determining the distance based on the MCS, at
514. For example, the distance may be determined based on whether
the MCS is a "high data rate" MCS (implying a short distance
between devices) or a "low data rate" MCS (implying a long distance
between devices). A modulation scheme specified by the MCS may
include binary phase-shift keying (BPSK), quadrature phase-shift
keying (QPSK), 16-point quadrature amplitude modulation (16-QAM),
or 64-point quadrature amplitude modulation (64-QAM). A coding rate
specified by the MCS may include 1/2, 3/4, 2/3, or .
[0065] The method 500 may include determining whether the distance
is within a discovery range threshold, at 516. For example, in FIG.
1, the second device 120 may determine whether the distance 102 is
within the discovery range threshold 114. When the distance is
outside the discovery range threshold, the method 500 may include
discarding the discovery message, at 518.
[0066] When the distance is within the discovery range threshold,
the method 500 may include decoding the discovery message, at 520.
The method 500 may also include displaying at least a portion of
the discovery message, at 522, and/or navigating to a URL in the
decoded discovery message, at 524. For example, in FIG. 1, the
second device 120 may display the information 131 and/or navigate
to the URL 132 via the browser application 123.
[0067] FIG. 6 is a flowchart of a particular embodiment of a method
600 of limiting wireless discovery range at a device based on time
elapsed between sending a RTS message and receiving a CTS message.
In an illustrative embodiment, the method 600 may be performed by
the first device 110 of FIG. 1.
[0068] The method 600 may include sending a RTS message from a
first device to a second device, at 602, and starting a timer at
the first device, at 604. For example, in FIG. 1, the first device
110 may send the RTS message 142 and start the timer 113. The
method 600 may also include receiving a CTS message at the first
device from the second device, at 606, and stopping the timer, at
608. For example, in FIG. 1, the first device 110 may receive the
CTS message 144 and stop the timer 113.
[0069] The method 600 may further include determining a distance
between the first device and the second device based on an elapsed
time between the sending of the RTS message and the receiving of
the CTS message, where the elapsed time is determined based on the
timer, at 610. For example, in FIG. 1, the first device 110 may
determine the distance 102 based on the timer 113.
[0070] The method 600 may include, in response to determining that
the distance is within a discovery range threshold, sending a
discovery message from the first device to the second device, at
612. For example, in FIG. 1, the first device 110 may send the
discovery message 130 to the second device 120 in response to
determining that the distance 102 is within the discovery range
threshold 114. If the distance is outside the discovery range
threshold, the first device may refrain from sending the discovery
message to the second device.
[0071] FIG. 7 is a flowchart of another particular embodiment of a
method 700 of limiting wireless discovery range at a device based
on time elapsed between sending a RTS message and receiving a CTS
message. In an illustrative embodiment, the method 700 may be
performed by the second device 120 of FIG. 1.
[0072] The method 700 may include sending a RTS message to a first
device from a second device, at 702, and receiving a CTS message
from the first device at the second device, at 704. For example, in
FIG. 1, the second device 120 may send the RTS message 152 to the
first device 110 and may receive the CTS message 154 in
response.
[0073] The method 700 may also include determining a distance
between the second device and the first device based on an elapsed
time between the sending of the RTS message and the receiving of
the CTS message, at 706. For example, in FIG. 1, the second device
120 may determine the distance 102. The method 700 may further
include determining whether the distance 102 is within a discovery
range threshold, at 708.
[0074] When the distance is within the discovery range threshold,
the method 700 may include decoding a discovery message, at 710. In
a particular embodiment, the discovery message may have been
received, at 701, prior to sending the RTS message. Alternately,
the discovery message may have been received, at 707, after
receiving the CTS message. For example, in FIG. 1, the second
device 120 may decode the discovery message 130 when the distance
102 is within the discovery range threshold 114.
[0075] When the distance is outside the discovery range threshold,
the method 700 may include discarding the discovery message, at
712. For example, in FIG. 1, the second device 120 may discard the
discovery message 130 when the distance 102 is outside the
discovery range threshold 114.
[0076] FIG. 8 is a flowchart of a particular embodiment of a method
800 of operating a wireless device. In an illustrative embodiment,
the method 800 may be performed by the second device 120 of FIG.
1.
[0077] The method 800 may include receiving a discovery message
from a first device at a second device, where the discovery message
includes a range adaptation bit, at 802. For example, in FIG. 1,
the second device 120 may receive the discovery message 130, where
the discovery message 130 includes the range adaptation bit
133.
[0078] The method 800 may also include determining a value of the
range adaptation bit, at 804. When the range adaptation bit has a
first value, the method 800 may include decoding the discovery
message, at 806. For example, in FIG. 1, when the range adaptation
bit 133 has a first value (e.g., zero), the second device 120 may
treat the discovery message 130 as range independent and may decode
the discovery message 130.
[0079] When the range adaptation bit has a second value, the method
800 may include determining a distance between the first device and
the second device, at 808. For example, in FIG. 1, when the range
adaptation bit 133 has a second value (e.g., one), the second
device 120 may treat the discovery message 130 as range adapted and
may determine the distance 102. The method 800 may further include
determining whether the distance is within a discovery range
threshold of the discovery message, at 810. For example, in FIG. 1,
the second device 120 may determine whether the distance 102 is
within the discovery range threshold 114 included in or otherwise
indicated by the discovery message 130.
[0080] When the distance is within the discovery range threshold,
the method 800 may include decoding the discovery message, at 812.
When the distance is outside the discovery range threshold, the
method 800 may include discarding the discovery message, at 814.
For example, in FIG. 1, the second device 120 may decode or discard
the discovery message 130 based on whether the distance 102 is
within the discovery range threshold 114.
[0081] Alternate embodiments of range determination may also be
performed in accordance with the disclosure herein. For example, a
service-providing device may receive a query message from a
service-seeking device. The query message may include a request to
set up a communication connection (e.g., a WiFi Direct connection)
between devices, a request for information regarding services
provided by a service-providing device, or some other message. In
response to the query message, the service-providing device may
determine a range.
[0082] In a particular embodiment, the service-providing device may
determine the range based on an RSSI (e.g., by comparing the RSSI
of the query message to a threshold). In another particular
embodiment, the service-providing device may determine the range by
initiating a round trip time (RTT) measurement operation (e.g., a
RTS/CTS message exchange). RTT measurement may involve measuring a
single message exchange or measuring multiple message exchanges
(e.g., multiple RTS/CTS exchanges) and determining an average. In
another particular embodiment, the service-providing device may use
an alternate (e.g., non-802.11 based) technology, such as Bluetooth
or near field communication (NFC), to determine the range. In
another particular embodiment, the service-providing device may use
GPS to determine the range, as described with reference to FIG. 1.
In another particular embodiment, the service-providing device may
perform range determination based on fixed wireless access points
or cellular towers (e.g., via triangulation of device positions).
In another particular embodiment, the service-providing device may
determine the range based on ranging with respect to a third device
(e.g., the service-providing device may indicate that a
service-seeking device is to be within a particular distance from
an AP to receive services). The choice of range determination
mechanism may be performed by software executing at a device above
a media access control (MAC) layer.
[0083] In response to determining that the range between the
service-providing device and the service-seeking device is within a
threshold, the service-providing device may initiate operations for
connection setup (e.g., set up a WiFi Direct connection).
[0084] In an alternate embodiment, the roles of the
service-providing and service-seeking device may be reversed. To
illustrate, a service-seeking device may receive a discovery
message from a service-providing device. In response to the
discovery message, the service-seeking device may determine a range
to the service-providing device. The range may be determined using
an RSSI of the discovery message, a RTT measurement operation, an
alternate (e.g., non-802.11 based) technology, GPS, fixed wireless
access points or cellular towers, or ranging with respect to a
third device. In response to determining that the range between the
service-seeking device and the service-providing device is within a
threshold, the service-seeking device may initiate operations for
connection setup (e.g., set up of a WiFi Direct connection).
[0085] Thus, a message (e.g., a query message or a discovery
message) may include data indicating whether a range determination
mechanism is to be used to determine whether to perform an action
in response to the message. To illustrate, a device may receive a
message and may decode the received message or a portion thereof
(e.g., a preamble or a header). The device may determine that the
message includes data indicating that range determination is to be
performed. In some embodiments, the message may identify the
particular type(s) of range determination mechanism(s) (e.g., RSSI,
RTT, GPS, alternate technology, etc.) to be used, as further
described with reference to FIGS. 10-11. If range determination
conditions are satisfied, the device may perform one or more
actions (e.g., decode the rest of the received message, initiate
connection setup, etc.).
[0086] It should be noted that the various range determination
methods described herein may be combined. For example, a range
determination hierarchy may include using RSSI as a gate keeping
indicator. If the RSSI of a received message is lower than an RSSI
threshold (e.g., indicating that the devices are separated by a
distance that is greater than or equal to a first range threshold),
the range determination process may end. Conversely, if the RSSI of
a received message satisfies the RSSI threshold (e.g., indicating
that the devices are separated by a distance that is less than the
first range threshold), the range determination process may
continue and a more accurate range determination mechanism may be
initiated (e.g., to determine whether the devices are within a
second range threshold). For example, a next level of the range
determination hierarchy may include initiating a RTT measurement
process. Thus, the RTT measurement process, which can take longer
(e.g., a few milliseconds) to perform than RSSI comparison, is not
initiated for messages that correspond to a low RSSI (i.e., RSSI
less than the RSSI threshold). As another example, the range
determination hierarchy may involve using alternate technologies
(e.g., Bluetooth, NFC, etc.) as a last resort, because use of such
technologies may involve powering up circuitry that is in a sleep
mode. In another particular embodiment, the range determination
hierarchy may include prioritizing use of such alternate technology
if available.
[0087] In a particular embodiment, in response to determining that
a range determination mechanism is to be executed, a device (e.g.,
a service-providing device and/or a service-seeking device) may
reserve a time period to execute the range determination mechanism.
For example, the time period may be reserved using a discovery
message. To illustrate, when a RTT measurement operation is to be
performed, time may be reserved to perform frame exchanges (e.g.,
RTS/CTS frame exchanges).
[0088] It should be noted that range determination may not merely
be a one-time check to determine whether or not to perform an
action in response to a discovery message or query message. For
example, when a first device (e.g., a service-seeking device or a
service-providing device) determines that range determination is to
be performed, the first device may perform range determination
multiple times to verify that the first device continues to remain
within a range threshold of a second device (e.g., a
service-providing device or a service-seeking device). To
illustrate, such range determination may be performed continuously
and/or periodically (e.g., by continuing to monitor RSSI, by
performing periodic RTT measurements etc.).
[0089] In a particular embodiment, discovery and/or query messages
may include a transmit power indication to assist receiving devices
in performing range determination. FIGS. 10-11 illustrate
particular embodiments of a discovery message (e.g., frames), such
as the discovery message 130 of FIGS. 1 and 9. For example, FIG. 10
illustrates a discovery frame 1001 that includes one or more
discovery type-length-values (TLVs) 1002.
[0090] Two embodiments of the discovery TLV(s) 1002 are shown in
FIG. 10 and designed 1002a and 1002b, respectively. The discovery
TLV(s) 1002 may include a six-byte service identifier (ID), as
shown. In a particular embodiment, the service ID may be a hash of
an application type or service type. For example, when a device
stores music videos, the service ID may be a six-byte hash of the
string "music videos."
[0091] In a particular embodiment, the discovery TLV(s) 1002 may
include a two-byte range control field 1003. The range control
field 1003 may include four bits that indicate the ranging
algorithm (e.g., range determination mechanism) in use (e.g., RSSI,
RTT, GPS, etc.).
[0092] FIG. 11 illustrates an alternate embodiment of a discovery
frame 1101. In FIG. 11, the discovery frame 1101 is a peer-to-peer
information element (P2P IE) that includes a P2P attributes field
1102. The P2P attributes field includes a range control field 1103,
as shown.
[0093] FIG. 9 is a block diagram of a mobile communication device
900. In one embodiment, the mobile communication device 900, or
components thereof, include or are included within the first device
110 FIG. 1, the second device 120 of FIG. 1, the museum transmitter
202 of FIG. 2, and/or the transmitters associated with the
paintings "P1" to "P9" of FIG. 2. Further, all or part of the
methods described in FIGS. 3-8 may be performed at or by the mobile
communication device 900. The mobile communication device 900
includes a processor 910, such as a digital signal processor (DSP),
coupled to a memory 932.
[0094] The memory 932 may be a non-transitory tangible
computer-readable and/or processor-readable storage device that
stores instructions 960. The instructions 960 may be executable by
the processor 910 to perform one or more functions or methods
described herein, such as the methods described with reference to
FIGS. 3-8. The memory 932 may also store the discovery range
threshold 114 and the table 125 associating RSSI values to expected
distances.
[0095] The processor 910 may also include, implement, or execute
device components described with reference to FIG. 1. For example,
the processor 910 may include an encoder 991 (e.g., the encoder 112
of FIG. 1), may include a decoder 992 (e.g., the decoder 122 of
FIG. 1), may execute a browser application 993 (e.g., the browser
application 123 of FIG. 1, and/or may start and stop a timer 994
(e.g., the timer 113 or the timer 124 of FIG. 1).
[0096] FIG. 9 also shows a display controller 926 that is coupled
to the processor 910 and to a display 928. For example, the display
928 may display information included in the discovery message 130,
as described with reference to the information 131 of FIG. 1. The
display 928 may also display the results of navigating to a URL
included in the discovery message 130, as described with reference
to the URL 132 of FIG. 1.
[0097] A coder/decoder (CODEC) 934 can also be coupled to the
processor 910. A speaker 936 and a microphone 938 can be coupled to
the CODEC 934. FIG. 9 also indicates that a wireless controller 940
can be coupled to the processor 910, where the wireless controller
940 is in communication with an antenna 942 via a transceiver 950.
The wireless controller 940, the transceiver 950, and the antenna
942 may thus represent a wireless interface that enables wireless
communication by the mobile communication device 900. For example,
such a wireless interface may be used to send or receive the
discovery message 130. The mobile communication device 900 may
include numerous wireless interfaces, where different wireless
networks are configured to support different networking
technologies or combinations of networking technologies.
[0098] In a particular embodiment, the processor 910, the display
controller 926, the memory 932, the CODEC 934, the wireless
controller 940, and the transceiver 950 are included in a
system-in-package or system-on-chip device 922. In a particular
embodiment, an input device 930 and a power supply 944 are coupled
to the system-on-chip device 922. Moreover, in a particular
embodiment, as illustrated in FIG. 9, the display 928, the input
device 930, the speaker 936, the microphone 938, the antenna 942,
and the power supply 944 are external to the system-on-chip device
922. However, each of the display device 928, the input device 930,
the speaker 936, the microphone 938, the antenna 942, and the power
supply 944 can be coupled to a component of the system-on-chip
device 922, such as an interface or a controller.
[0099] In conjunction with the described embodiments, an apparatus
may include means for determining, at a first device, a discovery
range threshold that limits a distance at which a second device is
operative to decode a discovery message from the first device. For
example, the means for determining may include a component of the
first device 110 of FIG. 1 (e.g., a processor), one or more
components of the mobile communication device 900 of FIG. 9, one or
more other devices configured to determine a discovery range
threshold, or any combination thereof. The apparatus may also
include means for adjusting a transmission attribute at the first
device based on the discovery range threshold. For example, the
means for adjusting may include the transmitter 111 of FIG. 1, one
or more components of the mobile communication device 900 of FIG.
9, one or more other devices configured to adjust a transmission
attribute, or any combination thereof. The apparatus may further
include means for sending the discovery message in accordance with
the adjusted transmission attribute. For example, the means for
sending may include the transmitter 111 of FIG. 1, one or more
components of the mobile communication device 900 of FIG. 9, one or
more other devices configured to send a message, or any combination
thereof.
[0100] In another aspect, an apparatus may include means for
receiving a discovery message from a first device at a second
device. For example, the means for receiving may include the
receiver 121 of FIG. 1, one or more components of the mobile
communication device 900 of FIG. 9, one or more other devices
configured to receive a message, or any combination thereof. The
apparatus may also include means for determining a distance between
the second device and the first device based on at least one
attribute of the discovery message. For example, the means for
determining may include a component of the second device 120 of
FIG. 1 (e.g., a processor), one or more components of the mobile
communication device 900 of FIG. 9, one or more other devices
configured to determine a distance, or any combination thereof. The
apparatus may further include means for decoding the discovery
message when the distance is within a discovery range threshold.
For example, the means for decoding may include the decoder 122 of
FIG. 1, one or more components of the mobile communication device
900 of FIG. 9, one or more other devices configured to decode a
message, or any combination thereof. The apparatus may include
means for discarding the discovery message when the distance is
outside the discovery range threshold. For example, the means for
discarding may include a component of the second device 120 of FIG.
1 (e.g., a processor), one or more components of the mobile
communication device 900 of FIG. 9, one or more other devices
configured to discard a message, or any combination thereof.
[0101] In another aspect, an apparatus may include means for
sending a range determination message from a first device to a
second device. For example, the means for sending may include the
transmitter 111 of FIG. 1, one or more components of the mobile
communication device 900 of FIG. 9, one or more other devices
configured to send a message, or any combination thereof. The
apparatus may also include means for receiving a range
determination response at the first device from the second device.
For example, the means for receiving may include the receiver 116
of FIG. 1, one or more components of the mobile communication
device 900 of FIG. 9, one or more other devices configured to
receive a message, or any combination thereof. The apparatus may
further include means for determining a distance between the first
device and the second device based on an elapsed time between the
sending of the range determination message and the receiving of the
range determination response. For example, the means for
determining may include the timer 113, another component of the
first device 110 of FIG. 1 (e.g., a processor), one or more
components of the mobile communication device 900 of FIG. 9, one or
more other devices configured to determine a distance based on an
elapsed time, or any combination thereof. The apparatus may include
means for sending a discovery message from the first device to the
second device in response to determining that the distance is
within a discovery range threshold. For example, the means for
sending may include the transmitter 111 of FIG. 1, one or more
components of the mobile communication device 900 of FIG. 9, one or
more other devices configured to send a message, or any combination
thereof.
[0102] In another aspect, an apparatus may include means for
sending a range determination message to a first device from a
second device. For example, the means for sending may include the
transmitter 126 of FIG. 1, one or more components of the mobile
communication device 900 of FIG. 9, one or more other devices
configured to send a message, or any combination thereof. The
apparatus may also include means for receiving a range
determination response from the first device at the second device.
For example, the means for receiving may include the receiver 121
of FIG. 1, one or more components of the mobile communication
device 900 of FIG. 9, one or more other devices configured to
receive a message, or any combination thereof. The apparatus may
further include means for determining a distance between the second
device and the first device based on an elapsed time between the
sending of the range determination message and the receiving of the
range determination response. For example, the means for
determining may include a component of the second device 120 of
FIG. 1 (e.g., a processor), one or more components of the mobile
communication device 900 of FIG. 9, one or more other devices
configured to determine a distance, or any combination thereof. The
apparatus may include means for decoding a discovery message
received from the first device when the distance is within a
discovery range threshold. For example, the means for decoding may
include the decoder 122 of FIG. 1, one or more components of the
mobile communication device 900 of FIG. 9, one or more other
devices configured to decode a message, or any combination thereof.
The apparatus may also include means for discarding the discovery
message received from the first device when the distance is outside
the discovery range threshold. For example, the means for
discarding may include a component of the second device 120 of FIG.
1 (e.g., a processor), one or more components of the mobile
communication device 900 of FIG. 9, one or more other devices
configured to discard a message, or any combination thereof.
[0103] In another aspect, an apparatus may include means for
determining a discovery range threshold at a first device. For
example, the means for determining may include a component of the
first device 110 of FIG. 1 (e.g., a processor), one or more
components of the mobile communication device 900 of FIG. 9, one or
more other devices configured to determine a discovery range
threshold, or any combination thereof. The apparatus may also
include means for sending a discovery message from the first device
to a second device. The discovery message may include data
indicating whether a range determination mechanism is to be used to
determine whether to perform an action (e.g., connection setup) in
response to the discovery message. For example, the means for
sending may include the transmitter 111 of FIG. 1, one or more
components of the mobile communication device 900 of FIG. 9, one or
more other devices configured to send a message, or any combination
thereof.
[0104] In another aspect, an apparatus may include means for
receiving a discovery message from a first device at a second
device, where the discovery message includes a range adaptation
indicator bit. For example, the means for receiving may include the
receiver 121 of FIG. 1, one or more components of the mobile
communication device 900 of FIG. 9, one or more other devices
configured to receive a discovery message, or any combination
thereof. The apparatus may also include means, responsive to the
range adaptation bit having a first value, for decoding the
discovery message. For example, the means for decoding may include
the decoder 122 of FIG. 1, one or more components of the mobile
communication device 900 of FIG. 9, one or more other devices
configured to decode a message, or any combination thereof. The
apparatus may further include means, responsive to the range
adaptation bit having a second value, for selectively decoding or
discarding the discovery message based on whether a distance
between the second device and the first device is within a
discovery range threshold included in the discovery message. For
example, the means for selectively decoding or discarding may
include the decoder 122 of FIG. 1, another component of the second
device 120 of FIG. 1 (e.g., a processor), one or more components of
the mobile communication device 900 of FIG. 9, one or more other
devices configured to selectively decode or discard a message, or
any combination thereof.
[0105] Those of skill would further appreciate that the various
illustrative logical blocks, configurations, modules, circuits, and
algorithm steps described in connection with the embodiments
disclosed herein may be implemented as electronic hardware,
computer software, or combinations of both. Various illustrative
components, blocks, configurations, modules, circuits, and steps
have been described above generally in terms of their
functionality. Whether such functionality is implemented as
hardware or software depends upon the particular application and
design constraints imposed on the overall system. Skilled artisans
may implement the described functionality in varying ways for each
particular application, but such implementation decisions should
not be interpreted as causing a departure from the scope of the
present disclosure.
[0106] The steps of a method or algorithm described in connection
with the embodiments disclosed herein may be embodied directly in
hardware, in a software module executed by a processor, or in a
combination of the two. A software module may reside in random
access memory (RAM), flash memory, read-only memory (ROM),
programmable read-only memory (PROM), erasable programmable
read-only memory (EPROM), electrically erasable programmable
read-only memory (EEPROM), registers, hard disk, a removable disk,
a compact disc read-only memory (CD-ROM), or any other form of
non-transitory storage medium known in the art. An exemplary
storage medium is coupled to the 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. The processor and the storage medium may reside in
an application-specific integrated circuit (ASIC). The ASIC may
reside in a computing device or a user terminal (e.g., a mobile
phone or a PDA). In the alternative, the processor and the storage
medium may reside as discrete components in a computing device or
user terminal.
[0107] The previous description of the disclosed embodiments is
provided to enable a person skilled in the art to make or use the
disclosed embodiments. Various modifications to these embodiments
will be readily apparent to those skilled in the art, and the
principles defined herein may be applied to other embodiments
without departing from the scope of the disclosure. Thus, the
present disclosure is not intended to be limited to the embodiments
disclosed herein but is to be accorded the widest scope possible
consistent with the principles and novel features as defined by the
following claims.
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