U.S. patent application number 15/682342 was filed with the patent office on 2017-11-30 for systems and methods for generating and decoding short control frames in wireless communications.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Santosh Abraham, Alfred Asterjadhi, Simone Merlin, Zhi Quan, Maarten Menzo Wentink.
Application Number | 20170347288 15/682342 |
Document ID | / |
Family ID | 51654365 |
Filed Date | 2017-11-30 |
United States Patent
Application |
20170347288 |
Kind Code |
A1 |
Merlin; Simone ; et
al. |
November 30, 2017 |
SYSTEMS AND METHODS FOR GENERATING AND DECODING SHORT CONTROL
FRAMES IN WIRELESS COMMUNICATIONS
Abstract
Systems, methods, and devices for communicating short control
frames are described herein. In some aspects, a method of wireless
communication includes generating a control frame comprising a
contention free end (CF-end) frame, the CF-end frame comprising a
physical layer preamble having a type field, the type field
including an indicator indicating the CF-end frame is a null data
packet (NDP). The method further includes transmitting the control
frame.
Inventors: |
Merlin; Simone; (San Diego,
CA) ; Abraham; Santosh; (San Diego, CA) ;
Wentink; Maarten Menzo; (Nijmegen, NL) ; Quan;
Zhi; (Livermore, CA) ; Asterjadhi; Alfred;
(San Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
51654365 |
Appl. No.: |
15/682342 |
Filed: |
August 21, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14097111 |
Dec 4, 2013 |
9781627 |
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15682342 |
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61809835 |
Apr 8, 2013 |
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61821149 |
May 8, 2013 |
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61865537 |
Aug 13, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 1/0079 20130101;
H04L 1/0029 20130101; H04L 1/0025 20130101; H04W 28/0273 20130101;
H04L 1/0073 20130101; H04W 74/002 20130101 |
International
Class: |
H04W 28/02 20090101
H04W028/02; H04L 1/00 20060101 H04L001/00; H04W 74/00 20090101
H04W074/00 |
Claims
1. A method of wireless communication, comprising: generating a
null data packet (NDP) control frame comprising a contention free
end (CF-end) frame, the NDP control frame comprising a physical
layer preamble having a type field, the type field including an
indicator indicating the CF-end frame; and transmitting the NDP
control frame.
2. The method of claim 1, wherein the type field includes 3
bits.
3. The method of claim 2, wherein the NDP control frame further
comprises an indicator differentiating between a CF-end and a clear
to send (CTS).
4. The method of claim 3, wherein the indicator comprises 1 bit,
wherein if the bit is set to 1 the NDP control frame is the CF-end,
and wherein if the bit is set to 0 the NDP control frame is the
CTS.
5. The method of claim 1, wherein the NDP control frame includes a
duration field.
6. The method of claim 5, wherein the duration field is set to 0,
or to a non-zero value of a network allocation vector (NAV) that
was sent from a previously transmitted frame of a wireless device,
to indicate the completion of a transmission opportunity.
7. The method of claim 5, wherein the duration field has a size of
10 bits in length indicating the NDP control frame has a 1 MHz
bandwidth.
8. The method of claim 5, wherein the duration field has a size of
15 bits in length indicating the NDP control frame has a greater
than or equal to 2 MHz bandwidth.
9. The method of claim 1, wherein the NDP control frame includes an
identifier, the identifier identifying a wireless device
transmitting the NDP control frame.
10. The method of claim 9, wherein the identifier is an association
identifier (AID) or a medium access control (MAC) address of the
wireless device.
11. The method of claim 9, wherein the identifier includes 9
bits.
12. The method of claim 1, wherein the NDP control frame includes
an identifier, the identifier having a value of a network
allocation vector (NAV) that was sent from a previously transmitted
frame of a wireless device.
13. A device for communicating in a wireless network, the device
comprising: a processor configured to generate a null data packet
(NDP) control frame comprising a contention free end (CF-end)
frame, the NDP control frame comprising a physical layer preamble
having a type field, the type field including an indicator
indicating the CF-end frame; and a transmitter configured to
transmit the NDP control frame.
14. The device of claim 13, wherein the type field includes 3
bits.
15. The device of claim 14, wherein the NDP control frame further
comprises an indicator differentiating between a CF-end and clear
to send (CTS).
16. The device of claim 15, wherein the indicator comprises 1 bit,
wherein if the bit is set to 1 the NDP control frame is the CF-end,
and wherein if the bit is set to 0 the NDP control frame is the
CTS.
17. The device of claim 13, wherein the NDP control frame includes
a duration field.
18. The device of claim 17, wherein the duration field is set to 0,
or to a non-zero value of a network allocation vector (NAV) that
was sent from a previously transmitted frame of the device, to
indicate the completion of a transmission opportunity.
19. The device of claim 17, wherein the duration field has a size
of 10 bits in length indicating the NDP control frame has a 1 MHz
bandwidth.
20. The device of claim 17, wherein the duration field has a size
of 15 bits in length indicating the NDP control frame has a greater
than or equal to 2 MHz bandwidth.
21. The device of claim 13, wherein the NDP control frame includes
an identifier, the identifier identifying a wireless device
transmitting the NDP control frame.
22. The device of claim 21, wherein the identifier is an
association identifier (AID) or a medium access control (MAC)
address of the device.
23. The device of claim 21, wherein the identifier includes 9
bits.
24. The device of claim 13, wherein the NDP control frame includes
an identifier, the identifier having a value of a network
allocation vector (NAV) that was sent from a previously transmitted
frame of the device.
25. A device for communicating in a wireless network, the device
comprising: means for generating a null data packet (NDP) control
frame comprising a contention free end (CF-end) frame, the NDP
control frame comprising a physical layer preamble having a type
field, the type field including an indicator indicating the CF-end
frame; and means for transmitting the NDP control frame.
26. The device of claim 25, wherein the type field includes 3
bits.
27. The device of claim 26, wherein the NDP control frame further
comprises an indicator differentiating between a CF-end and a clear
to send (CTS).
28. The device of claim 27, wherein the indicator comprises 1 bit,
wherein if the bit is set to 1 the NDP control frame is the CF-end,
and wherein if the bit is set to 0 the NDP control frame is the
CTS.
29. The device of claim 25, wherein the NDP control frame includes
a duration field.
30. The device of claim 29, wherein the duration field is set to 0,
or to a non-zero value of a network allocation vector (NAV) that
was sent from a previously transmitted frame of a wireless device,
to indicate the completion of a transmission opportunity.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 14/097,111, entitled "SYSTEMS AND METHODS FOR GENERATING
AND DECODING SHORT CONTROL FRAMES IN WIRELESS COMMUNICATIONS" and
filed on Dec. 4, 2013, which claims priority under 35 U.S.C.
.sctn.119(e) to provisional U.S. Application Ser. No. 61/865,537,
entitled "SYSTEMS AND METHODS FOR GENERATING AND DECODING SHORT
CONTROL FRAMES IN WIRELESS COMMUNICATIONS," filed Aug. 13, 2013,
provisional U.S. Application Ser. No. 61/821,149, entitled "SYSTEMS
AND METHODS FOR GENERATING AND DECODING SHORT CONTROL FRAMES IN
WIRELESS COMMUNICATIONS," filed May 8, 2013, and provisional U.S.
Application Ser. No. 61/809,835, entitled "SYSTEMS AND METHODS FOR
GENERATING AND DECODING SHORT CONTROL FRAMES IN WIRELESS
COMMUNICATIONS," filed Apr. 8, 2013, all of which applications are
hereby incorporated by reference in their entireties.
BACKGROUND
Field
[0002] The present application relates generally to wireless
communications, and more specifically to systems, methods, and
devices for communicating short control frames.
Background
[0003] In many telecommunication systems, communications networks
are 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 would be
designated respectively as a wide area network (WAN), metropolitan
area network (MAN), local area network (LAN), or personal area
network (PAN). Networks also differ according to the
switching/routing technique 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.).
[0004] Wireless networks are often preferred when the network
elements are mobile and thus have dynamic connectivity needs, or if
the network architecture is formed in an ad hoc, rather than fixed,
topology. Wireless networks employ intangible physical media in an
unguided propagation mode using electromagnetic waves in the radio,
microwave, infra-red, optical, etc. frequency bands. Wireless
networks advantageously facilitate user mobility and rapid field
deployment when compared to fixed wired networks.
[0005] The devices in a wireless network may transmit/receive
information between each other. The information may comprise
packets, which in some aspects may be referred to as data units.
The packets may comprise control frames. Control frames having
control information and payload data may cause significant overhead
and increased processing latency for receiving devices. As such,
systems, methods, and non-transitory computer-readable media are
needed for reducing network and processing overhead.
SUMMARY
[0006] The systems, methods, and devices of the invention each have
several aspects, no single one of which is solely responsible for
its desirable attributes. Without limiting the scope of this
invention as expressed by the claims which follow, some features
will now be discussed briefly. After considering this discussion,
and particularly after reading the section entitled "Detailed
Description" a person having ordinary skill in the art will
appreciate how the features of this invention provide advantages
that include decreasing the size of control frames.
[0007] One aspect of the disclosure provides a method of wireless
communication. The method comprises generating a control frame
comprising a contention free end (CF-end) frame, the CF-end frame
comprising a physical layer preamble having a type field, the type
field including an indicator indicating the CF-end frame is a null
data packet (NDP). The method further includes transmitting the
control frame.
[0008] Another aspect of the disclosure provides a wireless device
comprising a processor configured to generate a control frame
comprising a contention free end (CF-end) frame, the CF-end frame
comprising a physical layer preamble having a type field, the type
field including an indicator indicating the CF-end frame is a null
data packet (NDP). The wireless device further comprises a
transmitter configured to transmit the control frame.
[0009] Another aspect of the disclosure provides a method of
wireless communication. The method comprises generating a control
frame comprising a null data packet acknowledgement (NDP ACK) frame
or NDP modified ACK frame, the NDP ACK frame or NDP modified ACK
frame comprising a duration indication field, wherein the duration
indication field provides signaling information for the NDP ACK or
the NDP modified ACK. The method further includes transmitting the
control frame.
[0010] Another aspect of the disclosure provides a wireless device
comprising a processor configured to generate a control frame
comprising a null data packet acknowledgement (NDP ACK) frame or
NDP modified ACK frame, the NDP ACK frame or NDP modified ACK frame
comprising a duration indication field, wherein the duration
indication field provides signaling information for the NDP ACK or
the NDP modified ACK. The wireless device further comprises a
transmitter configured to transmit the control frame.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 illustrates an example of a wireless communication
system in which aspects of the present disclosure may be
employed.
[0012] FIG. 2 illustrates various components that may be utilized
in a wireless device that may be employed within the wireless
communication system of FIG. 1.
[0013] FIG. 3 illustrates an example of a control frame that may be
generated and communicated in the system of FIG. 1.
[0014] FIG. 4 illustrates another example of a control frame that
may be generated and communicated in the system of FIG. 1.
[0015] FIG. 5 illustrates another example of a control frame that
may be generated and communicated in the system of FIG. 1.
[0016] FIG. 6 is a table illustrating the fields that may be
included in a SIG field of an example of an ACK frame.
[0017] FIG. 7 is a table illustrating the fields that may be
included in a SIG field of another example of an ACK frame.
[0018] FIG. 8 illustrates another example of an ACK frame with a
format similar to the control frame of FIG. 5.
[0019] FIG. 9 shows a flow chart of an aspect of an exemplary
method for generating and transmitting a control frame.
[0020] FIG. 10 is a functional block diagram of an exemplary
wireless device that may be employed within the wireless
communication system of FIG. 1.
[0021] FIG. 11 shows a flow chart of an aspect of an exemplary
method for receiving and processing a control frame.
[0022] FIG. 12 is a functional block diagram of an exemplary
wireless device that may be employed within the wireless
communication system of FIG. 1.
[0023] FIG. 13 illustrates an example of a PS-poll frame.
[0024] FIG. 14 illustrates an example of an ACK frame.
[0025] FIG. 15 illustrates an example of a RTS frame.
[0026] FIG. 16 illustrates an example of a CTS frame.
[0027] FIG. 17 illustrates an example of a block ACK frame.
[0028] FIG. 18 illustrates an example of a NDP CF-end frame.
[0029] FIG. 19 illustrates an example of a 1 MHz NDP ACK frame.
[0030] FIG. 20 illustrates an example of a NDP ACK frame that has a
bandwidth greater than or equal to 2 MHz.
[0031] FIG. 21 illustrates an example of a 1 MHz NDP Modified ACK
frame.
[0032] FIG. 22 illustrates an example of a NDP Modified ACK frame
that has a bandwidth greater than or equal to 2 MHz.
[0033] FIGS. 23 and 24 illustrate examples of unified 1 MHz NDP ACK
frame and a unified NDP ACK frame that has a bandwidth greater than
or equal to 2 MHz.
[0034] FIGS. 25 and 26 illustrate examples of a 1 MHz NDP NAV ACK
frame and a NDP NAV ACK frame that has a bandwidth greater than or
equal to 2 MHz.
[0035] FIGS. 27 and 28 illustrate examples of a 1 MHz NDP IDE ACK
frame and a NDP IDE ACK frame that has a bandwidth greater than or
equal to 2 MHz.
[0036] FIG. 29 shows a flow chart of an aspect of an exemplary
method of wireless communication.
[0037] FIG. 30 shows a flow chart of an aspect of an exemplary
method of wireless communication.
[0038] FIG. 31 is a functional block diagram of an exemplary
wireless device that may be employed within the wireless
communication system 100.
DETAILED DESCRIPTION
[0039] Various aspects of the novel systems, apparatuses, and
methods are described more fully hereinafter with reference to the
accompanying drawings. The teachings in this disclosure may,
however, be embodied in many different forms and should not be
construed as limited to any specific structure or function
presented throughout this disclosure. Rather, these aspects are
provided so that this disclosure will be thorough and complete, and
will fully convey the scope of the disclosure to those skilled in
the art. Based on the teachings herein one skilled in the art
should appreciate that the scope of the disclosure is intended to
cover any aspect of the novel systems, apparatuses, and methods
disclosed herein, whether implemented independently of or combined
with any other aspect of the invention. For example, an apparatus
may be implemented or a method may be practiced using any number of
the aspects set forth herein. In addition, the scope of the
invention is intended to cover such an apparatus or method which is
practiced using other structure, functionality, or structure and
functionality in addition to or other than the various aspects of
the invention set forth herein. It should be understood that any
aspect disclosed herein may be embodied by one or more elements of
a claim.
[0040] Although particular aspects are described herein, many
variations and permutations of these aspects fall within the scope
of the disclosure. Although some benefits and advantages of the
preferred aspects are mentioned, the scope of the disclosure is not
intended to be limited to particular benefits, uses, or objectives.
Rather, aspects of the disclosure are intended to be broadly
applicable to different wireless technologies, system
configurations, networks, and transmission protocols, some of which
are illustrated by way of example in the figures and in the
following description of the preferred aspects. The detailed
description and drawings are merely illustrative of the disclosure
rather than limiting, the scope of the disclosure being defined by
the appended claims and equivalents thereof.
[0041] Wireless network technologies may include various types of
wireless local area networks (WLANs). A WLAN may be used to
interconnect nearby devices together, employing widely used
networking protocols. The various aspects described herein may
apply to any communication standard, such as WiFi or, more
generally, any member of the IEEE 802.11 family of wireless
protocols. For example, the various aspects described herein may be
used as part of the IEEE 802.11ah protocol, which uses sub-1 GHz
bands.
[0042] In some aspects, wireless signals in a sub-gigahertz band
may be transmitted according to the 802.11ah protocol using
orthogonal frequency-division multiplexing (OFDM), direct-sequence
spread spectrum (DSSS) communications, a combination of OFDM and
DSSS communications, or other schemes. Implementations of the
802.11ah protocol may be used for sensors, metering, and smart grid
networks. Advantageously, aspects of certain devices implementing
the 802.11ah protocol may consume less power than devices
implementing other wireless protocols, and/or may be used to
transmit wireless signals across a relatively long range, for
example about one kilometer or longer.
[0043] In some implementations, a WLAN includes various devices
which are the components that access the wireless network. For
example, there may be two types of devices: access points ("APs")
and clients (also referred to as stations, or "STAs"). In general,
an AP serves as a hub or base station for the WLAN and an STA
serves as a user of the WLAN. For example, an STA may be a laptop
computer, a personal digital assistant (PDA), a mobile phone, etc.
In an example, an STA connects to an AP via a WiFi (e.g., IEEE
802.11 protocol such as 802.11ah) compliant wireless link to obtain
general connectivity to the Internet or to other wide area
networks. In some implementations an STA may also be used as an
AP.
[0044] An access point ("AP") may also comprise, be implemented as,
or known as a NodeB, Radio Network Controller ("RNC"), eNodeB, Base
Station Controller ("BSC"), Base Transceiver Station ("BTS"). Base
Station ("BS"), Transceiver Function ("TF"), Radio Router, Radio
Transceiver, or some other terminology.
[0045] A station "STA" may also comprise, be implemented as, or
known as an access terminal ("AT"), a subscriber station, a
subscriber unit, a mobile station, a remote station, a remote
terminal, a user terminal, a user agent, a user device, user
equipment, or some other terminology. In some implementations an
access terminal may comprise a cellular telephone, a cordless
telephone, a Session Initiation Protocol ("SIP") phone, a wireless
local loop ("WLL") station, a personal digital assistant ("PDA"), a
handheld device having wireless connection capability, or some
other suitable processing device connected to a wireless modem.
Accordingly, one or more aspects taught herein may be incorporated
into a phone (e.g., a cellular phone or smartphone), a computer
(e.g., a laptop), a portable communication device, a headset, a
portable computing device (e.g., a personal data assistant), an
entertainment device (e.g., a music or video device, or a satellite
radio), a gaming device or system, a global positioning system
device, or any other suitable device that is configured to
communicate via a wireless medium.
[0046] As discussed above, certain of the devices described herein
may implement the 802.11ah standard, for example. Such devices,
whether used as an STA or AP or other device, may be used for smart
metering or in a smart grid network. Such devices may provide
sensor applications or be used in home automation. The devices may
instead or in addition be used in a healthcare context, for example
for personal healthcare. They may also be used for surveillance, to
enable extended-range Internet connectivity (e.g. for use with
hotspots), or to implement machine-to-machine communications.
[0047] FIG. 1 illustrates an example of a wireless communication
system 100 in which aspects of the present disclosure may be
employed. The wireless communication system 100 may operate
pursuant to a wireless standard, for example the 802.11ah standard.
The wireless communication system 100 may include an AP 104, which
communicates with STAs 106.
[0048] A variety of processes and methods may be used for
transmissions in the wireless communication system 100 between the
AP 104 and the STAs 106. For example, signals may be sent and
received between the AP 104 and the STAs 106 in accordance with
OFDM/OFDMA techniques. If this is the case, the wireless
communication system 100 may be referred to as an OFDM/OFDMA
system. Alternatively, signals may be sent and received between the
AP 104 and the STAs 106 in accordance with CDMA techniques. If this
is the case, the wireless communication system 100 may be referred
to as a CDMA system.
[0049] A communication link that facilitates transmission from the
AP 104 to one or more of the STAs 106 may be referred to as a
downlink (DL) 108, and a communication link that facilitates
transmission from one or more of the STAs 106 to the AP 104 may be
referred to as an uplink (UL) 110. Alternatively, a downlink 108
may be referred to as a forward link or a forward channel, and an
uplink 110 may be referred to as a reverse link or a reverse
channel.
[0050] The AP 104 may provide wireless communication coverage in a
basic service area (BSA) 102. The AP 104, along with the STAs 106
that are associated with the AP 104, may be referred to as a basic
service set (BSS). It should be noted that the wireless
communication system 100 may not have a central AP 104, but rather
may function as a peer-to-peer network between the STAs 106.
Accordingly, the functions of the AP 104 described herein may
alternatively be performed by one or more of the STAs 106.
[0051] FIG. 2 illustrates various components that may be utilized
in a wireless device 202 that may be employed within the wireless
communication system 100. The wireless device 202 is an example of
a device that may be configured to implement the various methods
described herein. For example, the wireless device 202 may comprise
the AP 104 or one of the STAs 106.
[0052] The wireless device 202 may include a processor 204 which
controls operation of the wireless device 202. The processor 204
may also be referred to as a central processing unit (CPU). Memory
206, which may include both read-only memory (ROM) and random
access memory (RAM), provides instructions and data to the
processor 204. A portion of the memory 206 may also include
non-volatile random access memory (NVRAM). The processor 204
typically performs logical and arithmetic operations based on
program instructions stored within the memory 206. The instructions
in the memory 206 may be executable to implement the methods
described herein.
[0053] The processor 204 may comprise or be a component of a
processing system implemented with one or more processors. The one
or more processors may be implemented with any combination of
general-purpose microprocessors, microcontrollers, digital signal
processors (DSPs), field programmable gate array (FPGAs),
programmable logic devices (PLDs), controllers, state machines,
gated logic, discrete hardware components, dedicated hardware
finite state machines, or any other suitable entities that can
perform calculations or other manipulations of information.
[0054] The processing system may also include machine-readable
media for storing software. Software shall be construed broadly to
mean any type of instructions, whether referred to as software,
firmware, middleware, microcode, hardware description language, or
otherwise. Instructions may include code (e.g., in source code
format, binary code format, executable code format, or any other
suitable format of code). The instructions, when executed by the
one or more processors, cause the processing system to perform the
various functions described herein.
[0055] The wireless device 202 may also include a housing 208 that
may include a transmitter 210 and a receiver 212 to allow
transmission and reception of data between the wireless device 202
and a remote location. The transmitter 210 and receiver 212 may be
combined into a transceiver 214. An antenna 216 may be attached to
the housing 208 and electrically coupled to the transceiver 214.
The wireless device 202 may also include (not shown) multiple
transmitters, multiple receivers, multiple transceivers, and/or
multiple antennas.
[0056] The wireless device 202 may also include a signal detector
218 that may be used in an effort to detect and quantify the level
of signals received by the transceiver 214. The signal detector 218
may detect such signals as total energy, energy per subcarrier per
symbol, power spectral density and other signals. The wireless
device 202 may also include a digital signal processor (DSP) 220
for use in processing signals. The DSP 220 may be configured to
generate a data unit for transmission. In some aspects, the data
unit may comprise a physical layer data unit (PPDU). In some
aspects, the PPDU is referred to as a packet.
[0057] The wireless device 202 may further comprise a user
interface 222 in some aspects. The user interface 222 may comprise
a keypad, a microphone, a speaker, and/or a display. The user
interface 222 may include any element or component that conveys
information to a user of the wireless device 202 and/or receives
input from the user.
[0058] The various components of the wireless device 202 may be
coupled together by a bus system 226. The bus system 226 may
include a data bus, for example, as well as a power bus, a control
signal bus, and a status signal bus in addition to the data bus.
Those skilled in the art will appreciate the components of the
wireless device 202 may be coupled together or accept or provide
inputs to each other using some other mechanism.
[0059] Although a number of separate components are illustrated in
FIG. 2, those skilled in the art will recognize that one or more of
the components may be combined or commonly implemented. For
example, the processor 204 may be used to implement not only the
functionality described above with respect to the processor 204,
but also to implement the functionality described above with
respect to the signal detector 218 and/or the DSP 220. Further,
each of the components illustrated in FIG. 2 may be implemented
using a plurality of separate elements.
[0060] As discussed above, the wireless device 202 may comprise an
AP 104 or an STA 106, and may be used to transmit and/or receive
communications. The communications exchanged between devices in a
wireless network may include data units which may comprise packets
or frames. In some aspects, the data units may include three types
of frames, including data frames, control frames, and management
frames. Data frames may be used for transmitting data from an AP
and/or a STA to other APs and/or STAs. Control frames may be used
together with data frames for performing various operations and for
reliably delivering data (e.g., acknowledging receipt of data,
polling of APs, area-clearing operations, channel acquisition,
carrier-sensing maintenance functions, etc.). Management frames may
be used for various supervisory functions (e.g., for joining and
departing from wireless networks, etc.).
[0061] As discussed above, the DSP 220 and/or the processor 204 may
be configured to generate a data unit for transmission. In some
aspects, the generated data unit may comprise a control frame
including control information and optionally a plurality of data
symbols. Control frames may be used to assist in the delivery of
data frames and may be included in a medium access control (MAC)
header. Control frames included in a MAC header with control
information and data symbols (e.g., payload data) may cause
significant overhead and increased processing latency for receiving
devices. For example, control frames may include protocol
information, control type information, address information, payload
data, etc. In some aspect, the information included in control
frames may not always be necessary for the particular use of a
control frame. As such, systems, methods, and non-transitory
computer-readable media are needed for generating and decoding
short control frames. For example, short control frames may be
generated by omitting some information from the control frame
and/or by including the control frame in other packet locations,
such as a physical layer (PHY) preamble. For example, the control
frame may comprise a physical layer (PHY) preamble that includes a
plurality of fields. The fields may include one or more training
fields (e.g., a short training field (STF) and a long training
field (LTF)), for example, and a signal (SIG) field. Each of the
training fields may include a known sequence of bits or symbols. In
some aspects, the SIG field may include information about the data
unit, for example a description of a length or data rate of the
data unit (e.g., a LENGTH field, a modulation coding scheme (MCS)
field, a bandwidth (BW) field, etc.). In some aspects, short
control frames may be generated by encoding control frames in the
SIG field of the PHY preamble.
[0062] FIG. 3 illustrates an example of a control frame 300 that
may be generated and communicated in the system of FIG. 1. As
shown, the control frame 300 includes an STF field 305, and LTF
field 310, and a control SIG field 315. For example, the control
frame 300 may be a PHY preamble. In some aspects, the PHY preamble
may comprise a physical layer convergence protocol (PLCP) layer, as
defined in the IEEE 802.11 specifications. The STF field 305
includes one or more STFs. The LTF field 310 includes one or more
LTFs. The control information for the control frame 300 may be
included in the SIG field 315. Further, in some aspects, the
control frame may not include any additional fields or data (e.g.,
payload). As a result, network overhead may be reduced and
throughput and processing of data packets may be increased.
[0063] FIG. 4 illustrates another example of a control frame 400
that may be generated and communicated in the system of FIG. 1. As
shown, the control frame 400 includes an STF field 405, and LTF
field 410, a control SIG field 415, and a control extension field
420. Similar to the control frame 300, the STF field 405 includes
one or more STFs and the LTF field 410 includes one or more LTFs.
Further, similar to the control frame 300, the control information
for the control frame 400 may be included in the SIG field 415.
However, unlike the control frame 300, additional control
information may be included in the control extension field 420. For
example, the PHY preamble of the control frame 400 may comprise the
STF field 405, LTF field 410, and control SIG field 415. However,
there may be additional control information that does not fit in
the PHY preamble of the control frame 400. Accordingly, the
additional control information may be included in the control
extension field 420 which may be located in a portion (e.g., a few
symbols) of a data portion of the control frame 400. The control
extension field 420 of the control frame 400 may be sent with a
default MCS that may be predetermined or negotiated in a different
message (e.g., at association or in beacons) between the
transmitter and the receiver. In one aspect, the MCS of the control
extension field 420 may be indicated in the SIG field 415. Both
control frame 300 and control frame 400 may be used for
communication. For example, control frame 300 may be utilized where
the control information fits in the SIG field 315. Further, control
frame 400 may be utilized where the control information does not
fit in the SIG field 315. In some aspects, the LENGTH field of the
SIG field may further indicate whether or not the control extension
field is included in a control frame.
[0064] FIG. 5 illustrates another example of a control frame 500
that may be generated and communicated in the system of FIG. 1. As
shown, the control frame 500 includes an STF field 505, and LTF
field 510, a SIG field 515, a SERVICE field 520, a frame control
(FC) field 525, a control information (INFO) field 530, and a frame
check sequence (FCS) field 535. The control information of the
control frame 500 may be included in the control INFO field
530.
[0065] The type of control information included in any of the above
control frames 300, 400, and 500 (or any other suitable control
frame) may be dependent on the type of control frame. For example,
various different control frames may be generated and communicated
by wireless devices 202. Different types of control frames used in
the wireless system of FIG. 1 may include one or more of the
following control frame types: acknowledgment (ACK), power save
poll (PS-poll), request to send (RTS), clear to send (CTS), block
ACK request (BAR), block ACK (BA), contention free-end (CF-end),
CF-end poll. MCS request, MCS response, NULL data packet (NDP),
probe request, and probe response. The control information may
comprise fields of information. Different control frame types may
comprise different fields of information. The various fields of
information that may be included in the different types of control
frames are described herein. It should be noted that the fields
described below do not necessarily need to be included in the
control frame in the same order as described. Rather, the fields
may be included in any order or any portion of the control frame
where control information is included (e.g., SIG field, control
extension field, control field, etc.). For example, the fields may
be ordered by priority. The order of the fields for a given control
frame type may be predetermined (e.g., programmed at manufacture of
the device or upon initialization of the device, communicated in a
separate message between wireless devices 202), however, such that
the wireless devices 202 has information regarding which bits in
the control frame correspond to which fields.
[0066] In some aspects, certain fields may be included in all
control frames, regardless of the type. For example, in some
aspects, a type field may be included in all the control frames,
where the type field identifies the type of the control frame. The
type field may be, for example, 2, 3 or 4 bits long. Interpretation
of the remaining bits (e.g., determination of which bits correspond
to which fields and which fields are included) in the control frame
may be based on the type of the control frame and whether the frame
is even a control frame. For example, in some aspects, a value of 0
of a LENGTH field of a SIG field of the frame may indicate that the
frame is a short control frame such as the control frame 300 or
400. If the LENGTH field has a different value it may indicate the
frame is of a different type (e.g., a data frame, a management
frame, or a different type of control frame). The SIG field may
further include a type field which then indicates the type of
control frame. In some other aspects, any value less than a
particular value (e.g., 10) of the LENGTH field of a SIG field of
the frame may indicate that the frame is a control frame, such as
the control frame 300 or 400. Further, the type of control frame
may be based on the value of the LENGTH field, meaning each value
0-10 may be associated with a different control frame type. In some
other aspects, a 1-bit type field (type indication field) may be
added to the frames in general that indicates whether or not the
frame is a control frame (or in particular a short format control
frame), such as the control frame 300 or 400, or not (e.g., a data
frame, a management frame, or a different type of control frame)
depending on the value of the bit. In some aspects, a 1 bit type
indication field may indicate that the short format control frame
is a null data packet (NDP) that may be located in a physical layer
(PHY) preamble and may omit a MAC header field, a FCS, or a service
field. The remaining bits of the type field may indicate the type
of control frame (i.e. acknowledgment (ACK), power save poll
(PS-poll), request to send (RTS), clear to send (CTS), block ACK
request (BAR), block ACK (BA), contention free-end (CF-end), CF-end
poll, etc.). In some other aspects, one or more reserved values of
fields that are defined in frames may be used to indicate if the
frame is a control frame (or in particular a short format control
frame), such as the control frame 300 or 400, or not (e.g., a data
frame, a management frame, or a different type of control frame).
For example, one or more reserved values of the MCS field in the
SIG field could be used to indicate if the frame is a control frame
and/or the type of control frame. In this case, a further field
indicating the type may not be needed. For example, an unused value
of a space-time block codes (STBC) field may be used. Multiple
fields may also be used in combination to identify the control
frame. LENGTH and MCS may also be used in combination to indicate
the type of control frame. For example, the LENGTH field may have a
value (e.g., 0) that may indicate the frame is of a certain type
(e.g., NDP), while a different value of the LENGTH field (e.g.,
LENGTH>0) may indicate that the type of control frame is
indicated by the MCS.
[0067] Similarly a 1-bit type field may be used in combination with
the LENGTH field to indicate the type of control frame. For
example, a value (e.g., 0) of a 1-bit type field may indicate that
the frame is a control frame of a type other than a certain type
(e.g., NDP). Further, another value (e.g., 1) of the 1-bit type
field may indicate that the frame is of the certain type (e.g.,
NDP) if the LENGTH field has a certain value (e.g., 0), or not a
control frame if the LENGTH field has a different value (e.g.,
LENGTH >0).
[0068] Further, in some aspects, a cyclic redundancy check (CRC)
field may be included in all types of control frames. The CRC field
may be used to validate the frame is correctly received. The CRC
may be, for example, 4 or 5 bits long. Further, in some aspects, a
transmit (TX) power indication may be included in all types of
control frames. The TX power indication may be used by a receiver
of the control frame to estimate pathloss or change behavior of the
receiver based on the TX power of the transmitter of the control
frame.
[0069] Further, in some aspects, a non-valid combination of values
in one or more fields within the SIG field may be used to indicate
whether the frame is a control frame. For example, a coding field
may include two subfields (e.g., one bit each). A first subfield of
the coding field may indicate the coding type (e.g., binary
convolutional coding (BCC) or low density parity check (LDPC)
coding). A second subfield of the coding field may indicate how to
compute the length of the frame. For example, the second subfield
may be set to 0 when the first subfield indicates a BCC coding
type. A value of 01 in the coding field is not valid for normal
non-control frames, thus the value 01 can be used to indicate that
the frame is a control frame. Similar procedures may apply to other
fields or combination of fields in the SIG field. Further, a short
control frame will include a type field that identifies the type of
control frame.
[0070] In some aspects, the control frame may be sent with a PHY
preamble that occupies a 1 MHz bandwidth or a bandwidth greater
than or equal to 2 MHz. The bandwidth of the frame may be
implicitly determined from the PHY preamble structure. For example,
the STF and/or LTF of the PHY preamble may be used to determine
whether the bandwidth of the frame is 1 MHz or greater than or
equal to 2 MHz.
[0071] In some aspects, the control frame may be replicated across
multiple 1 MHz bandwidth channels or across multiple bandwidth
channels that are greater than or equal to 2 MHz, e.g. multiple
copies of the control frame may be sent on multiple channels, which
may or may not be adjacent. A receiver of such a control frame may
determine the number of channels the frame may be replicated on. In
one aspect, the info field or the SIG field of the PHY preamble of
the control frame may include an indication of the bandwidth or
total number of channels on which the frame is replicated. For
example, 2-bits of the info field or the SIG field may be used as
follows: [0072] 00: frame is not replicated [0073] 01: replicated
on 2 channels [0074] 10: replicated on 4 channels [0075] 11:
replicated on 8 channels [0076] where the `channel` may be a 1 MHz
bandwidth channel or a bandwidth channel that is greater than or
equal to 2 MHz depending on whether the frame is a 1 MHz bandwidth
frame or a bandwidth frame that is greater than or equal to 2
MHz.
[0077] In some aspects, one type of control frame is an ACK. For
example, the STA 106a may send data to the AP 104. Upon successful
receipt of the data, the AP 104 may send an ACK to the STA 106a
indicating successful receipt of the data to the STA 106a. In some
aspects, the ACK may be sent in response to successful receipt of
at least one of the following: a data frame, a management frame, a
control frame, a PS-Poll, or another type of frame. In one aspect,
the control information of an ACK may consist of, or consist
essentially of, one or more of the fields described above as being
included in all types of control frames (e.g., type field. CRC, TX
power, etc.) and one or more of the following fields: an address,
an identifier of a packet being acknowledged, an indication for
rate control, an indication of buffered data, a duration, and a
Doppler indication. In one aspect, the duration field may be 9 bits
or less and can be used to update the network allocation vector
(NAV). In another aspect, the ACK may be sent as a response to
trigger frames, e.g., PS-poll or QoS (quality of service) null, in
which case the duration field may indicate the data delivery time
of the buffered units that the AP has available for that particular
STA. In some aspects, the duration may be expressed in microseconds
or in multiples of a time unit (e.g., the time slot or a
pre-defined value for which the AP and the STA agree during
association, re-association, or sent with management frames). The
control information (e.g., the INFO field, control info field,
etc.) of the ACK may not include any additional fields.
[0078] In some aspects, the duration may indicate a time delay
rather than NAV setting. In such implementations, the duration may
be expressed in microseconds (or as a multiple of another time
unit, e.g., ms) and it may indicate to a first STA that sent a
trigger frame (the frame that triggered a second STA to transmit a
null data packet (NDP) ACK frame) that the first STA should not
send any further data to the second STA for the amount of time
indicated in the duration field of the NDP ACK frame. In one
embodiment, the way a STA interprets the duration field may depend
on a value of a duration indication bit. As an example, if the
duration indication is set to 0, the duration field indicates a NAV
duration, while if it is set to 1, it indicates a time delay during
which the STA should not access the medium as described above. In
another embodiment, the type of the NDP frame may implicitly
indicate how a STA should interpret the duration field. In one
embodiment, the reason for postponing access to the medium for the
STA receiving the ACK, may be to notify it that the STA that
generated the NDP ACK frame is encountering some problems in
delivering the following frames to a destination. As an example, a
Relay STA (AP) may indicate to the associated STA that its buffers
are full and the Relay cannot store anymore packets in the transmit
buffer. In another embodiment, the AP/Relay/STA may use this
duration indication for other purposes such as entering a power
save mode for that duration, or to indicate that it cannot process
any more data for that duration, etc. In one embodiment, the NDP
ACK may include one or more bits specifying the reason the STA
should delay transmitting for the period of time indicated in the
duration field of the NDP ACK frame. In some implementations, the
indication of the duration in the NDP ACK frame may be used by
other STAs associated to that same AP/Relay STA to behave the same
as the intended receiver of the ACK frame such that they may defer
accessing the medium to send packets to the AP/Relay STA for that
duration of time. In one embodiment, this functionality of the NDP
ACK can be obtained in a similar way by using other types of NDP
frames, such as NDP SID, NDP Modified ACK or NDP CTS frames.
[0079] In some aspects, the address field of the ACK may include
one or more global addresses (e.g., a MAC address, BSSID) that
uniquely identifies a transmitter and/or a receiver of the ACK
globally (e.g., in a network). In some aspects, the address field
may include one or more local addresses (e.g., an association
identifier (AID)) that uniquely identifies a transmitter and/or
receiver of the ACK locally (e.g., in a local network such as in a
particular BSS). In some aspects, the address field may include a
partial or non-unique identifier (e.g., a portion of a MAC address
or AID) that identifies a transmitter and/or receiver of the ACK.
For example, the address field of the ACK may comprise at least a
portion of the AID or MAC address of the transmitter and/or
receiver of the ACK. The at least a portion of the AID or MAC
address may be copied from the frame being acknowledged by the
ACK.
[0080] In some aspects, the identifier field of the ACK may
identify the frame being acknowledged (e.g., one or more MAC
protocol data units (MPDUs)). For example, in one aspect, the
identifier field may be a hash of the content of the frame. In
another aspect, the identifier field may include at least a portion
of the CRC (e.g., the FCS field) of the frame. In another aspect,
the identifier field may be based on at least a portion of the CRC
(e.g., the FCS field) of the frame and at least a portion of a
local address (e.g., AID of an STA). In another aspect, the
identifier field may be a sequence number of the frame. In another
aspect, the identifier field may be computed based on one or more
of the following in any combination: a global address of the
transmitter/receiver of the ACK, a local address of the
transmitter/receiver of the ACK, a portion of a global address of
the transmitter/receiver of the ACK, a portion of a local address
of the transmitter/receiver of the ACK, a sequence number (or a
portion of the sequence number) of one of the MPDUs being
acknowledged, a portion of the CRC (e.g., the FCS field) of the
frame being acknowledged, or a portion of a scrambling seed of the
frame being acknowledged. For example, in one aspect, the
identifier field may include a hash of a global address (e.g.,
BSSID, MAC address of an AP) and a local address (e.g., AID of an
STA).
(dec(AID[0:8])+dec(BSSID[44:47]XOR BSSID[40:43])2 5)mod 2 9 (1)
[0081] where dec( ) is a function that converts a hexadecimal
number to a decimal number.
[0082] In another aspect, the identifier field of the ACK may
include a combination of a portion of the FCS of the frame being
acknowledged and the scrambling seed or value found in the SERVICE
field of the frame, or sequence number of the frame. For example,
the combination may comprise a sum operation or a copy operation of
some bits of the FCS and scrambling seed into some bits of the ACK
identifier. In some aspects, the identifier included in the ACK may
be different depending on the type/subtype of the frame. As an
example, if the frame being acknowledged is a data frame or
management frame, the identifier may be based on the sequence
number of the MPDU in the frame, or it may be any other identifier
described herein provided the necessary information is present in
the data or management packet. If the frame is a control frame
(e.g. a PS-Poll), the frame may not have a sequence number and
hence in this case the identifier may be based on the FCS of the
PS-Poll frames, the PS-Poll identifier or on a token number or any
other identifier described herein for which the control frame
provides the necessary information.
[0083] In some aspects, the identifier included in the ACK may be
different depending on the type/subtype of the frame being
acknowledged. As an example, if the frame is a data or management
frame, the identifier may be based on a combination of a partial
sequence number of the MPDU in the frame and any other identifier
described herein provided the necessary information is present in
the data or management packet. The length of the partial sequence
number included in the ACK ID may be a function of the maximum
number of MPDUs that a Block ACK frame can acknowledge. As an
example, a partial sequence number of 6 bits in length is
sufficient to distinguish among multiples of blocks of 64 MPDUs. In
this aspect, the ACK frame may be able to perform Block ACK
functionalities.
[0084] As an example, if the frame is a control frame (e.g. a
PS-Poll), the frame does not have a sequence number and hence in
this case the identifier may be based on the FCS of the PS-Poll
frames, on a token number, or any other identifier described herein
for which the control frame provides the necessary information. As
an additional example, if the ACK is sent as a response to a
PS-Poll control frame that is defined based on the concepts
described herein, the ACK identifier may be the same as the PS-Poll
identifier.
[0085] In some aspects, the identifier field of the ACK includes
one or more of the least significant bits of the receiver address
(e.g., address 1) of the frame being acknowledge. The receiver
address in the frame could be a full MAC address or a local address
(AID) depending on the frame format. In some aspects, the
identifier field of the ACK includes one or more of the least
significant bits of the receiver address combined (e.g., summed
with some other computation with) a scrambling seed (or a portion
of the scrambling seed) from the SERVICE field of the soliciting
frame.
[0086] In some aspects, the identifier field of the ACK is the last
one or more bits of the frame being acknowledged. It should be
noted that any of the above discussed examples for the identifier
field of the ACK may be included with any suitable short control
frame such as those described herein and in response to any type of
frame.
[0087] In some aspects, the frame for which the ACK is sent in
response may include a token number set by the transmitter of the
frame. The transmitter of the frame may generate the token number
based on an algorithm. In some aspects, the token number generated
by the transmitter may have a different value for each frame sent
by the transmitter. In such aspects, the receiver of the frame may
use the token number in the identifier field of the ACK to identify
the frame being acknowledged such as by setting the identifier as
the token number or computing the identifier based at least in part
on the token number. In some aspects, the identifier field may be
computed as a combination of the token number with at least one of
the following: a global addresses of the transmitter/receiver of
the ACK, a local addresses of the transmitter/receiver of the ACK,
a portion of global addresses of the transmitter/receiver of the
ACK, a portion of local addresses of the transmitter/receiver of
the ACK, or a portion of a CRC of the frame.
[0088] In some other aspects, the token number may be included in
another field of the ACK and/or frame being acknowledged such as a
SIG field and/or a control information (Control Info) field. In
some aspects, the token may be derived from a scrambling seed in a
SERVICE field, which may come after a PHY preamble, of the frame
being acknowledged.
[0089] In some aspects, an indication of rate control field of the
ACK may include one or more bits that indicate the MCS that the
receiver of the frame (the transmitter of the ACK) suggests that
the transmitter of the frame should use. For example, in one
aspect, the value of the one or more bits may indicate that the MCS
should either be lowered, raised, or stay the same and may indicate
by how much the MCS should change. In another aspect, the value of
the one or more bits may indicate a specific MCS. The frame may
further include a number of spatial streams indication, which
indicates the number of spatial streams used to transmit the
frame.
[0090] In some aspects, an indication of buffered data indicates
that the transmitter of the ACK has data buffered and ready to be
sent to a receiver of the ACK. For example, a STA 106a may poll the
AP 104 (such as through a PS-poll message) to determine whether the
AP 104 has data buffered to send to the STA 106a. The AP 104 may
therefore respond with an ACK having an indication of buffered data
field acknowledging successful receipt of the poll, and where the
value of the field indicates whether the AP 104 has data buffered
or not.
[0091] FIG. 6 is a table illustrating the fields that may be
included in a SIG field of an example of an ACK frame. In the
illustrated aspect, the SIG field consists or consists only of a
control field 605 of 1 bit, a type field 610 of 3 bits, an
address/identifier field 615 of 13 bits for an AID or 32 bits for
an FCS or 40 bits for a partial MAC address, a rate adaptation
information field 620 of 1-4 bits, a CRC field 625 of 4 bits, and a
tail field 630 of 6 bits. The control field 605 indicates if the
frame is a control frame as described above. The type field 610
defines the type of the frame as described above. The
address/identifier field 615 corresponds to one of the address
field or identifier field as described above. The rate adaptation
information field 620 corresponds to the indication of rate control
field as described above. The CRC field 625 corresponds to a CRC of
the ACK frame. The tail field 630 corresponds to information needed
by the PHY layer to decode the ACK frame.
[0092] FIG. 7 is a table illustrating the fields that may be
included in a SIG field of another example of an ACK frame. In the
illustrated aspect, the SIG field consists or consists only of a
length field 705 of 12 or 9 bits, optionally (depending on whether
the length field indicates the type as discussed above) a type
field 710, an address/identifier field 715 of 13 bits for an AID or
32 bits for an FCS or 40 bits for a partial MAC address, a CRC
field 725 of 4 bits, and a tail field 730 of 6 bits. The length
field 705 corresponds to the length field described above. The type
field 710 defines the type of the frame as described above. The
address/identifier field 715 corresponds to one of the address
field or identifier field as described above. The CRC field 725
corresponds to a CRC of the ACK frame. The tail field 730
corresponds to information needed by the PHY layer to decode the
ACK frame.
[0093] FIG. 8 illustrates another example of an ACK frame with a
format similar to the control frame of FIG. 5. As shown, the ACK
frame 800 comprises an STF field 805, and LTF field 810, a SIG
field 815, a SERVICE field 820, a FC field 825, and a FCS field
830. In this embodiment, no control information may be included in
the ACK frame. Rather, the FCS field 830 may be modified to
indicate the frame is an ACK frame. In particular, the FCS field
830, instead of including a CRC of the ACK frame 800, may include a
copy of the FCS of the frame being acknowledged. A recipient of the
ACK frame 800 may determine the frame is an ACK frame 800 if it
sent a frame with the same FCS. In some aspects, the transmitter of
the frame may expect the ACK frame 800 within a particular time
interval and therefore may only check if incoming packets have the
copied FCS for that time interval. Further, in some aspects, the FC
field 825 may include an indicator that indicates whether or not
the frame is an ACK.
[0094] FIG. 14 illustrates another example of an ACK frame 1400
according to the teachings herein. As shown, the ACK frame 1400
includes a MCS of 4 bits (that indicates the type of control
frame), an ACK ID of 14 bits (that may consist of a partial FCS and
scrambler seed), a duration of 5 bits, an other field of 3 or 15
bits, a cyclic redundancy check of 4 bits and a tail of 6 bits.
[0095] In some aspects, a method of wireless communication
comprises generating an acknowledgment frame comprising control
information consisting essentially of the following: one or more of
a length field, a cyclic redundancy check field, and a transmit
power indication field, and one or more of an address field, an
identifier field, an indication for rate control field, and an
indication of buffered data field. The method further comprises
transmitting the acknowledgment frame. In some aspects, the address
field includes one of a global address or a local address. In some
aspects, the address field includes one of an address of a
transmitter of the acknowledgment frame or a receiver of the
acknowledgment frame.
[0096] In some aspects, the identifier field includes one of a hash
of a packet being acknowledged, a cyclic redundancy check of the
packet being acknowledged, a token, or a sequence number of the
packet being acknowledged.
[0097] In some aspects, the indication for rate control field
indicates an amount to change a modulation coding scheme. In some
aspects, the indication for rate control field indicates a
modulation coding scheme.
[0098] In some aspects, the acknowledgement frame comprises
information based on at least a frame check sequence of a packet
being acknowledged. In some aspects, the information based at least
on the frame check sequence comprises an identifier based on the
frame check sequence and one or more of the following: a scrambling
seed from a service field of the packet being acknowledged and a
sequence number from the packet being acknowledged. In some
aspects, the information is based on a type of the packet being
acknowledged.
[0099] In some aspects, one type of control frame is a PS-poll. For
example, the STA 106a may send a PS-poll to the AP 104 to determine
whether the AP 104 has data to send to the STA 106a. In one aspect,
the control information of a PS-poll may consist of or consist
essentially of one or more of the fields described above as being
included in all types of control frames (e.g., type field, CRC, TX
power, etc.) and one or more of the following fields: a global
address of the receiver of the PS-poll, a local address of a sender
of the PS-poll, an information field, and a field indicating a
token number. As discussed above, the token number may be generated
by the transmitter of the PS-poll (e.g., according to an algorithm)
and may have a different value for each PS-poll sent by the
transmitter. The control information of the PS-poll may not include
any additional fields. The information field may include the latest
beacon version of that the sender of the PS-poll has received so
the receiver of the PS-poll can compare the sender's version to the
actual version. In another aspect, the information field may
include one or more of the following in any combination: a global
address of the transmitter/receiver of the PS-poll, a local address
of the transmitter/receiver of the PS-poll, a portion of a global
address of the transmitter/receiver of the PS-poll, a portion of a
local address of the transmitter/receiver of the PS-poll, or the
scrambler seed (or a portion of the scramble seed) of the beacon
that carries the traffic indication map (TIM) for which the PS-poll
is being sent. For example, the information field may include, in
any order, a BSSID of an AP and an AID of an STA. If there is a
mismatch between the sender's version and the actual version, the
receiver of the PS-poll can send new information to the sender of
the PS-poll.
[0100] In some aspects, the control information of the PS-poll may
include an identifier. The identifier value may be set to the same
value of, or to a value derived from, a corresponding identifier
(e.g., scrambler seed) included in a beacon (e.g., latest received
beacon) or other paging frame received by the STA 106a from the AP
104. When the identifier is present, the receiver address of the
PS-Poll may be omitted from the frame, since the identifier
identifies the intended receiver. Furthermore, the PS-Poll may
include a part of its AID (e.g., 11 LSBs of its AID) in the PS-Poll
identifier. Further, the sender of the beacon or paging message can
change the identifier for any given beacon, providing diversity
across time.
[0101] FIG. 13 illustrates an example of a PS-poll control frame
1300 including a MCS of 4 bits (that indicates the type of control
frame), a receiver address of 7 bits, a transmitter address of 11
bits, an other field of 4 or 16 bits, a cyclic redundancy check of
4 bits and a tail of 6 bits.
[0102] In some aspects, PS-poll frames may be used in conjunction
with ACK frames as follows. A STA may send a PS-poll intended for
an AP with which the STA is associated. Upon receipt of the
PS-poll, the AP may respond with an ACK frame, such as those
described herein. For example, the ACK frame may include an
identifier computed based on a token number included in the PS-poll
frame as described above. The token may be the PS-Poll identifier.
Using the token number in responses beneficially allows the
identifier of the ACK to be different for each PS-poll, thereby
allowing a device to easily differentiate between multiple ACKs if
multiple ACKS are received by the device at the same time. In
another example, the ACK frame may include one or more of the
following in any combination: a global address of the
transmitter/receiver of the PS-poll, a local address of the
transmitter/receiver of the PS-poll, a portion of a global address
of the transmitter/receiver of the PS-poll, or a portion of a local
address of the transmitter/receiver of the PS-poll, which may be
copied from the PS-poll.
[0103] In some aspects, a method of wireless communication
comprises generating a power save poll frame comprising control
information consisting essentially of the following: one or more of
a length field, a cyclic redundancy check field, a transmit power
indication field, a destination address field, a transmitter
address field, and an information field. The method further
comprises transmitting the power save poll frame. In some aspects,
the information field includes a beacon version. In some aspects,
the destination address field comprises a global address and the
transmitter address field comprises a local address. In some
aspects, the information field includes an identifier based on a
received beacon.
[0104] In some aspects, one type of control frame is a RTS. In one
aspect, the control information of a RTS may consist of or consist
essentially of one or more of the fields described above as being
included in all types of control frames (e.g., type field, CRC, TX
power, etc.) and one or more of the following fields: a global
address of the receiver of the RTS, a local address of a sender of
the RTS, and a duration field. The control information of the RTS
may not include any additional fields. In some aspects, the RTS may
additionally or alternatively include a transmit power indication
(along with the one or more of the fields described above as being
included in all types of control frames) which can be expressed in
dB or in classes (e.g., 2 bits can indicate 4 classes of transmit
powers). Furthermore, the RTS may additionally or alternatively
include a bandwidth indication (along with the one or more of the
fields described above as being included in all types of control
frames). In one aspect, the bandwidth indication may be present
only for 2 MHz (or more) control frames. The duration field may
indicate the duration for which the RTS reserves a communication
channel. In one aspect, the duration field may indicate the
duration in 2 bytes (or less) and express duration in his. In
another aspect, the duration may indicate the duration in other
time intervals (e.g., number of symbols, multiples of 40 .mu.s,
number of time slots, etc.). As an example, with a duration field
length of 9 bits and expressed as multiples of 40 us the duration
field can indicate up to 20.5 ms. In some aspects, the length of
the time interval is declared by the AP 104 and sent in another
message such as a beacon or during association to the STA 106a.
[0105] In some aspects, a method of wireless communication
comprises generating a request to send frame comprising control
information consisting essentially of the following: one or more of
a length field, a cyclic redundancy check field, a transmit power
indication field, a destination address field, a transmitter
address field, and a duration field. The method further comprises
transmitting the request to send frame. In some aspects, the
destination address field comprises a global address and the
transmitter address field comprises a local address. In some
aspects, the duration field expresses duration in multiples of
symbols.
[0106] FIG. 15 illustrates an example of a RTS control frame 1500
including a MCS of 4 bits (that indicates the type of control
frame), a RTS ID of 13 bits (e.g., the receivers AID), a duration
field of 9 bits, an other field, a cyclic redundancy check of 4
bits and a tail of 6 bits. The RTS 1500 may additionally include a
bandwidth indication of 2 bits and/or may additionally include a
transmit power class of 2 bits.
[0107] In some aspects, one type of control frame is a CTS. In one
aspect, the control information of a CTS may consist of or consist
essentially of one or more of the fields described above as being
included in all types of control frames (e.g., type field, CRC, TX
power, etc.) and one or more of the following fields: a local
address of a sender of the RTS for which the CTS is being sent and
a duration field. The local address and duration field may be
copied (or derived) from the RTS for which the CTS is being sent.
In some embodiments, the CTS identifier may be 9 bits long and may
consist of the concatenation of the 3 least significant bits of the
FCS and the 6 most significant bits of the Service field of the RTS
frame. Alternatively, the CTS may not include an address copied
from the RTS and instead may include an identifier, defined in
similar ways as for the ACK frame discussed above. The control
information of the CTS may not include any additional fields.
Alternatively, the CTS may include the additional fields described
previously for the RTS frame.
[0108] FIG. 16 illustrates an example of a CTS control frame 1600
including a MCS of 4 bits (that indicates the type of control
frame), a CTS ID of 7 bits (e.g., partial fcs and scrambler seed
information from RTS and/or partial transmitter address of the
transmitter if CTS is transmitted to self and/or a copy (or a part)
of the RTS ID), a duration field of 9 bits, an other field of 6 or
18 bits, a cyclic redundancy check of 4 bits and a tail of 6 bits.
The CTS 1600 may additionally include a bandwidth indication of 2
or 3 bits and/or may additionally include a transmit power class of
2 bits.
[0109] In some aspects, the CTS control frame 1600 may further
include an MCS field including one or more bits indicating a
suggested MCS for data transmission, which may be used, for
example, to implement fast link adaptation. For example, upon
reception of a RTS frame from a second STA, a first STA may
transmit the CTS control frame 1600 and use the MCS field the frame
1600 to indicate to the second STA a suggested MCS that the second
STA may use for the following data transmission to it. The second
STA may choose the MCS indicated in the MCS field in order to
select the MCS for the following data transmission.
[0110] In some aspects, the MCS field may indicate an MCS index,
according to the MCS definition in the IEEE standard. In some
aspects, the MCS field may include a relative MCS, including an
indication to increase or decrease the MCS with respect to a given
reference MCS. For example, the reference MCS may be an MCS used
for the transmission of the soliciting RTS. As another example, the
reference MCS may be an MCS explicitly indicated in a field of the
soliciting RTS. As another example, the reference MCS may be an MCS
used in the last successful data transmission. In some aspects, the
CTS may further include an indication that the sender of the CTS
has buffered data units or frames ready to be delivered to the
recipient of the CTS.
[0111] In some aspects, the MCS field of the CTS control frame 1600
may include two bits to indicate the suggested MCS. For example,
the following combination of bits may be used to indicate a
suggested MCS: [0112] 00: same MCS as RTS [0113] 01: MCS of RTS
`+1` [0114] 10: MCS of RTS `+2` [0115] 11: MCS of RTS `+3`
[0116] As another example, if the RTS frame is sent at MCS2 rep 2,
then: [0117] 00: MCS0 rep2 [0118] 01: MCS0 [0119] 10: MCS1 [0120]
11: MCS2
[0121] In some aspects, the CTS control frame 1600 may include 1
bit used to indicate that the CTS is a response to the RTS but it
is not granting the transmission opportunity (TXOP) to the STA. For
example, the CTS control frame 1600 may indicate that the RTS was
received, but the network allocation vector (NAV) is not set and
the transmitter of the RTS is not granted the possibility to send
data after the CTS. In some aspects, if the CTS control frame 1600
indicates that it is not granting the TXOP, a duration field of the
CTS control frame 1600 is not used to indicate the NAV duration. In
such aspects, the duration field may be used to indicate a time
after which the STA is allowed to send another RTS frame or
data.
[0122] In some aspects, a method of wireless communication
comprises generating a clear to send frame comprising control
information consisting essentially of the following: one or more of
a length field, a cyclic redundancy check field, a transmit power
indication field, a destination address field and a duration field.
The method further comprises transmitting the clear to send frame.
In some aspects, the clear to send control frame comprises a
physical layer preamble having a signal field that includes the
control information.
[0123] In some aspects, one type of control frame is a BAR. For
example, the STA 106a may send BAR to another STA requesting the
other STA to send a BA. In one aspect, the control information of a
BAR may consist of or consist essentially of one or more of the
fields described above as being included in all types of control
frames (e.g., type field, CRC, TX power, etc.) and one or more of
the following fields: a global address, a local address, an address
interpretation field, a traffic identifier (TID) field, and a
starting sequence number field. The control information of the BAR
may not include any additional fields. The global address may be a
global address of the transmitter of the BAR or the receiver of the
BAR. The local address may be a local address for the other of the
transmitter of the BAR and the receiver of the BAR for which a
global address is not included in the BAR. The address
interpretation field may be 1 or 2 bits that indicate whether the
global address is the address of the transmitter and the local
address is the address of the receiver or if the global address is
the address of the receiver and the local address is the address of
the transmitter. Since a BA is defined per TID, and a sequence
number of the starting block for which the BA is requested is
needed, these values are included in the BAR. The TID may be 3 bits
and the starting sequence number may be 12 bits. In some aspects,
the start sequence number may be a partial sequence number, such as
one or more of the least or most significant bits of the start
sequence number. The length of the partial sequence number may
depend on the maximum number of MPDUs that a Block ACK can
acknowledge. As an example, a partial Sequence Number of 6 bits in
length is sufficient to distinguish among multiples of blocks of 64
MPDUs. In some aspects, the TID identifies the Access Category, and
per each access category it identifies 2 sub categories, for a
total of 8. In other aspects, an indication of the Access Category
is sufficient. In some aspects, instead of a 3-bit TID, the control
field may include a 2-bit Access Category.
[0124] In another aspect, the control information of a BAR may
consist of or consist essentially of one or more of the fields
described above as being included in all types of control frames
(e.g., type field, CRC, TX power, etc.) and one or more of the
following fields: a global address, a first local address, a second
local address, a traffic identifier (TID) field, and a starting
sequence number field. The control information of the BAR may not
include any additional fields. The global address may indicate a
BSSID of the transmitter and receiver. The first and second local
addresses may be local addresses of the transmitter and
receiver.
[0125] In another aspect, the control information of a BAR may
consist of or consist essentially of one or more of the fields
described above as being included in all types of control frames
(e.g., type field, CRC, TX power, etc.) and one or more of the
following fields: a first global address, a second global address,
a traffic identifier (TID) field, and a starting sequence number
field. The control information of the BAR may not include any
additional fields. The first and second global addresses may be
global addresses of the transmitter and receiver.
[0126] In some aspects, a method of wireless communication
comprises generating a block acknowledgment request frame
comprising control information consisting essentially of the
following: one or more of a length field, a cyclic redundancy check
field, a transmit power indication field, a global address field, a
local address field, an address interpretation field, a traffic
identifier field, and a starting sequence number field. The method
further comprises transmitting the block acknowledgment request
frame.
[0127] In some aspects, one type of control frame is a BA. For
example, the STA 106a may send a BA to acknowledge receipt of
multiple frames. In one aspect, the control information of a BA may
consist of or consist essentially of one or more of the fields
described above as being included in all types of control frames
(e.g., type field. CRC, TX power, etc.) and one or more of the
following fields: a global address, a local address, an address
interpretation field, a traffic identifier (TID) field, a starting
sequence number field, and a bitmap. The control information of the
BA may not include any additional fields. The global address may be
a global address of the transmitter of the BA or the receiver of
the BA. The local address may be a local address for the other of
the transmitter of the BA and the receiver of the BAR for which a
global address is not included in the BA. The address
interpretation field may be 1 or 2 bits that indicate whether the
global address is the address of the transmitter and the local
address is the address of the receiver or if the global address is
the address of the receiver and the local address is the address of
the transmitter. Since a BA is defined per TID, and a sequence
number of the starting block for which the BA is requested is
needed, these values are included in the BA. The TID may be 3 bits
and the starting sequence number may be 12 bits. Further, the
bitmap may be, for example, 4, 8, 16, 32, or 64 bits. The value of
the bitmap may indicate which frames were successfully received and
which were not received. In some aspects, any of the TID, sequence
number and receiver address may be excluded from the BA as the
transmitter of a BAR may expect the BA within a particular time
interval from a specific responder. Therefore, if a BA is received
in that time interval with the address of the transmitter, the
transmitter may assume the TID and starting sequence number sent in
the BAR.
[0128] In another aspect, the control information of a BA may
consist of or consist essentially of one or more of the fields
described above as being included in all types of control frames
(e.g., type field, CRC, TX power, etc.) and one or more of the
following fields: a global address, a first local address, a second
local address, a traffic identifier (TID) field, a starting
sequence number field, and a bitmap. The control information of the
BA may not include any additional fields. The global address may
indicate a BSSID of the transmitter and receiver. The first and
second local addresses may be local addresses of the transmitter
and receiver.
[0129] In another aspect, the control information of a BA may
consist of or consist essentially of one or more of the fields
described above as being included in all types of control frames
(e.g., type field, CRC, TX power, etc.) and one or more of the
following fields: a first global address, a second global address,
a traffic identifier (TID) field, a starting sequence number field,
and a bitmap. The control information of the BA may not include any
additional fields. The first and second global addresses may be
global addresses of the transmitter and receiver.
[0130] In another aspect, the control information of a BA may
consist of or consist essentially of one or more of the fields
described above as being included in all types of control frames
(e.g., type field, CRC, TX power, etc.) and one or more of the
following fields: a bitmap and a BA identifier. The control
information of the BA may not include any additional fields. The
bitmap may be a 2, 4, 8, 16, 32 bitmap indicating whether the
corresponding packet was received correctly or not received. A bit
in position n of the bitmap may refer to a packet with sequence
number equal to n plus the sequence number indicated in the BAR
frame immediately preceding the BA. In some aspects, the TID or AC
value is also assumed to be the one from the immediately preceding
BAR. The identifier may be defined in the same or similar ways as
defined for the ACK identifier.
[0131] FIG. 17 illustrates an example of a BA frame 1700 according
to the teachings herein. As shown, the BA frame 1700 includes a MCS
of 4 bits (that indicates the type of control frame), a block ACK
ID of 7 bits (e.g., scrambler seed from a first MPDU or a BAR), a
starting sequence number (SSN) of 5 bits (e.g., the SSN of the
first MPDU acknowledged or the 5 LSB of the SSN of the first MPDU
acknowledged), a bitmap of 8 bits or 16 bits, an other field, a
cyclic redundancy check of 4 bits and a tail of 6 bits. In some
aspects, the BA frame 1700 may include an ACK mode field of 1 bit
that indicates if the BA is for block acknowledgments or fragmented
acknowledgements. In some aspects, the BA frame 1700 may include a
1 bit Doppler indication field.
[0132] In some aspects, a method of wireless communication
comprises generating a block acknowledgment frame comprising
control information consisting essentially of the following: one or
more of a length field, a cyclic redundancy check field, a transmit
power indication field, a global address field, a local address
field, an address interpretation field, a traffic identifier field,
a starting sequence number field, and a bitmap. The method further
comprises transmitting the block acknowledgment frame.
[0133] In some aspects, one type of control frame is a CF-end that
is a null data packet (NDP). In one embodiment, the CF-end may be
used to cancel a reservation made in response to a network
allocation vector (NAV). In one aspect, the control information of
a CF-end may consist of or consist essentially of a type field. The
control information of the CF-end may not include any additional
fields. Any receiver receiving the type field indicating CF-end may
then determine any NAV should be canceled. In another aspect, the
control information of a CF-end may consist of or consist
essentially of a type field and one or more of the other fields
described above as being included in all types of control frames
(e.g., type field, CRC. TX power, etc.). The control information of
the CF-end may not include any additional fields. As a result, this
short format CF-end, or NDP CF-end, may reduce network overhead and
may increase throughput and processing of data packets.
[0134] FIG. 18 illustrates an example of a NDP CF-end frame 1800
according to the teachings herein. As shown, the NDP CF-end frame
1800 includes a NDP type field of 3 bits (that indicates the type
of control frame), an identifier field that identifies NDP CF-end
of 7 or more bits, a duration field of 10 or 15 bits, a NDP subtype
field of 1 bit, a NDP indication field of 1 bit that indicates
whether the control frame is a NDP frame (i.e., short control
frame), a cyclic redundancy check of 4 bits and a tail of 6
bits.
[0135] In some aspects, the (NDP) CF-end may have the same value of
a type field (for example by using a 3 bit type field) of an NDP
CTS frame and the differentiation between an NDP CF-end frame and
the NDP CTS frame may be based on a subtype field (for example
using 1 bit). In this embodiment, if the subtype field is set to 1
the NDP frame is a NDP CF-end. Otherwise, the NDP frame is an NDP
CTS. In some aspects, the NDP CF-end may include a duration field
that if present may be set by the generating STA to 0 to indicate
the completion of the TXOP (i.e., set the NAV of the receiving STAs
to 0). In some aspects, the STA generating the NDP CF-end frame may
set the duration field of the NDP CF-end to a non-zero value, e.g.,
if the NDP CF-end is sent some constant time (e.g., PIFS time)
after the transmission of a NDP CTS frame, the duration field of
the NDP CF-end frame may be set to the same value of the duration
field of the NDP CTS-Frame minus the constant time (e.g., PIFS). In
this embodiment, the STA generating the NDP CF-end indicates to a
group of the receiving STAs (the ones that have their NAV set to a
value that equals the duration field of the CF-end) to reset their
NAV value. The other STAs that have a different value of their NAV
counter shall not reset their NAVs. In one embodiment, the size of
the duration field size may be 10 bits in length for a 1 MHz NDP
CF-end frame and 15 bits for a NDP CF-end frame that has a
bandwidth greater than or equal to 2 MHz. In one embodiment, NDP
CF-end frame may include an identifier for the NDP CF-end frame.
The STA generating the NDP CF-end may set the identifier of the NDP
CF-end to the same value as (part of) the identifier of the device
(e.g., the AID or the MAC address of the STA as described in this
application). In another embodiment, the identifier of the NDP
CF-end may be set to the same value as the latest NAV-Setting frame
that the STA transmitted immediately previously the NDP CF-end
frame (e.g., a (NDP) CTS, or data frame). In one embodiment, the
length of the identifier may be 9 bits and it may have the same
value as an NDP CTS frame. In some aspects, a method of wireless
communication comprises generating a contention-free end frame
comprising control information consisting essentially of a type
field. The method further comprises transmitting the CF-end
frame.
[0136] In some aspects, one type of control frame is a CF-end poll.
The CF-end poll may be used itself to cancel a reservation made in
response to a network allocation vector (NAV) in the transmission
range of the transmitter of the CF-end poll and further request a
receiver of the CF-end poll to transmit a CF-end to cancel the
reservation in the transmission range of the receiver of the CF-end
poll. In one aspect, the control information of a CF-end poll may
comprise a global address of the receiver of the CF-end poll and
one or more of the fields described above as being included in all
types of control frames of a type field. In another aspect, the
control information of a CF-end poll may consist of or consist
essentially of a global address of the receiver of the CF-end poll
and one or more of the fields described above as being included in
all types of control frames of a type field. In another aspect, the
control information of a CF-end poll may consist of or consist
essentially of a global address of the receiver of the CF-end poll
and a type field indicating the frame is a CF-end poll.
[0137] In some aspects, a method of wireless communication
comprises generating a contention-free end poll frame comprising
control information consisting essentially of the following: one or
more of a length field, a cyclic redundancy check field, a transmit
power indication field, and a recipient global address field. The
method further comprises transmitting the contention-free end poll
frame.
[0138] In some aspects, one type of control frame is a MCS request.
For example, an AP 104 may send an MCS request to the STA 106a to
request from the STA 106a information as to which MCS to use for
transmissions. In one aspect, the control information of a MCS
request may consist of or consist essentially of one or more of the
fields described above as being included in all types of control
frames (e.g., type field, CRC, TX power, etc.) and one or more of
the following fields: a global address of the receiver of the MCS
request and a local address of a sender of the MCS request. The
control information of the MCS request may not include any
additional fields.
[0139] In some aspects, a method of wireless communication
comprises generating a modulation coding scheme request frame
comprising control information consisting essentially of the
following: one or more of a length field, a cyclic redundancy check
field, a transmit power indication field, a recipient global
address field, and a transmitter local address field. The method
further comprises transmitting the modulation coding scheme request
frame.
[0140] In some aspects, one type of control frame is a MCS
response. For example, an AP 104 may send an MCS request to the STA
106a to request from the STA 106a information as to which MCS to
use for transmissions. In return, the STA 106a may send such
information in an MCS response. In one aspect, the control
information of a MCS response may consist of or consist essentially
of one or more of the fields described above as being included in
all types of control frames (e.g., type field. CRC, TX power, etc.)
and one or more of the following fields: a local address of a
sender of the MCS request for which the MCS response is sent as
copied from the MCS request, a MCS field (e.g., 4 bits), and extra
information (e.g., signal-to-noise ratio (SNR)). The control
information of the MCS response may not include any additional
fields.
[0141] In some aspects, a method of wireless communication
comprises generating a modulation coding scheme response frame
comprising control information consisting essentially of the
following: one or more of a length field, a cyclic redundancy check
field, a transmit power indication field, a recipient local address
field, a modulation coding scheme field, and an information field.
The method further comprises transmitting the modulation coding
scheme response frame.
[0142] In some aspects, one type of control frame is a NDP. For
example, an AP 104 may send an NDP to the STA 106a to allow the STA
106a to perform channel estimation using the NDP. In one aspect,
the control information of a NDP may consist of or consist
essentially of one or more of the fields described above as being
included in all types of control frames (e.g., type field, CRC, TX
power, etc.) and one or more of the following fields: a number of
spatial streams for channel estimation and a channel bandwidth over
which to estimate. The control information of the NDP may not
include any additional fields.
[0143] In some aspects, a method of wireless communication
comprises generating a null data packet frame comprising control
information consisting essentially of the following: one or more of
a length field, a cyclic redundancy check field, a transmit power
indication field, a number of spatial streams field, and a channel
bandwidth field. The method further comprises transmitting the null
data packet frame.
[0144] In some aspects, one type of control frame is a probe
request. For example, an STA 106a looking for an AP may send a
probe request that an AP 104 responds to. In one aspect, the
control information of a probe request may consist of or consist
essentially of one or more of the fields described above as being
included in all types of control frames (e.g., type field, CRC, TX
power, etc.) and one or more of the following fields: a global
address of the transmitter of the probe request and a service set
identifier (SSID) field. The control information of the probe
request may not include any additional fields. The SSID field may
include a SSID or hash of an SSID for which the STA 106a is
looking. The hash of the SSID may be for instance 4 bytes
representing a portion of the full SSID or a CRC computed based on
the full CRC. Further, the SSID field may not be included and thus
any AP receiving the probe request may respond.
[0145] In some aspects, a method of wireless communication
comprises generating a probe request frame comprising control
information consisting essentially of the following: one or more of
a length field, a cyclic redundancy check field, a transmit power
indication field, a transmitter global address field, and a
receiver service set identifier field. The method further comprises
transmitting the probe request frame.
[0146] In some aspects, one type of control frame is a probe
response. For example, an STA 106a looking for an AP may send a
probe request that an AP 104 responds to with a probe response. In
one aspect, the control information of a probe response may consist
of or consist essentially of one or more of the fields described
above as being included in all types of control frames (e.g., type
field, CRC, TX power, etc.) and one or more of the following
fields: a global address of the transmitter of the probe response,
a global address of the receiver of the probe response, and a
service set identifier (SSID) field. The control information of the
probe response may not include any additional fields. The SSID
field may include a SSID or hash of an SSID of the AP sending the
probe response. Further, the SSID field may not be included for
example if the probe request includes an SSID as the transmitter of
the probe request may expect the probe response within a particular
time interval. Therefore, if a probe response is received in that
time interval with the address of the transmitter of the probe
request, the transmitter may assume the SSID sent in the probe
request.
[0147] In some aspects, a method of wireless communication
comprises generating a probe response frame comprising control
information consisting essentially of the following: one or more of
a length field, a cyclic redundancy check field, a transmit power
indication field, a transmitter global address field, a receiver
global address field, and a transmitter service set identifier
field. The method further comprises transmitting the probe response
frame.
[0148] FIG. 9 shows a flowchart of an aspect of an exemplary method
900 for generating and transmitting a control frame. The method 900
may be used to generate and transmit any of the control frames
described above. The control frame may be generated or transmitted
from one wireless device 202 to another wireless device. Although
the method 900 is described below with respect to elements of the
wireless device 202 (FIG. 2), those having ordinary skill in the
art will appreciate that other components may be used to implement
one or more of the steps described herein. Although blocks may be
described as occurring in a certain order, the blocks can be
reordered, blocks can be omitted, and/or additional blocks can be
added.
[0149] First, at block 902, the processor 204 and/or the DSP 220
generates a control frame based on the content of the control
frame. Then, at a block 904, the transmitter 210 transmits the
control frame.
[0150] FIG. 10 is a functional block diagram of an exemplary
wireless device 1000 that may be employed within the wireless
communication system 100. The device 1000 comprises a generating
module 1002 for generating a control frame for wireless
transmission. The generating module 1002 may be configured to
perform one or more of the functions discussed above with respect
to the block 902 illustrated in FIG. 9. The generating module 1002
may correspond to one or more of the processor 204 and the DSP 220.
The device 1000 further comprises a transmitting module 1004 for
wirelessly transmitting the data unit. The transmitting module 1004
may be configured to perform one or more of the functions discussed
above with respect to the block 904 illustrated in FIG. 9. The
transmitting module 1004 may correspond to the transmitter 210.
[0151] FIG. 11 shows a flow chart of an aspect of an exemplary
method 1100 for receiving and processing a control frame. The
method 1100 may be used to receive and process any of the control
frames described above. The control frame may be received and
processed at any wireless device 202. Although the method 1100 is
described below with respect to elements of the wireless device 202
(FIG. 2), those having ordinary skill in the art will appreciate
that other components may be used to implement one or more of the
steps described herein. Although blocks may be described as
occurring in a certain order, the blocks can be reordered, blocks
can be omitted, and/or additional blocks can be added.
[0152] First, at block 1102, the receiver 212 receives a control
frame. Then, at a block 1104, the processor 204 and/or the DSP 220
processes the control frame based on the content of the control
frame.
[0153] FIG. 12 is a functional block diagram of an exemplary
wireless device 1200 that may be employed within the wireless
communication system 100. The device 1200 comprises a receiving
module 1002 for receiving a control frame. The receiving module
1202 may be configured to perform one or more of the functions
discussed above with respect to the block 1102 illustrated in FIG.
11. The receiving module 1202 may correspond to the receiver 212.
The device 1200 further comprises a processing module 1204 for
processing the control frame. The transmitting module 1204 may be
configured to perform one or more of the functions discussed above
with respect to the block 1104 illustrated in FIG. 11. The
processing module 1204 may correspond to one or more of the
processor 204 and the DSP 220.
[0154] As described above, one type of control frame is an
acknowledgement (ACK) frame. For example, the STA 106a may send
data to the AP 104 and, upon successful receipt of the data, the AP
104 may send an ACK to the STA 106a indicating successful receipt
of the data to the STA 106a. In some aspects, the ACK may be sent
in response to successful receipt of at least one of the following:
a data frame, a management frame, a control frame, a PS-Poll, or
another type of frame.
[0155] In some embodiments, an ACK frame may include a null data
packet (NDP) ACK frame. In one embodiment, one type of NDP ACK
frame includes an NDP ACK for all MAC protocol data units (MPDUs),
which may be referred to herein as an NDP ACK frame. An NDP ACK
frame may be a mandatory frame that is sent in response to all
MPDUs, such as, for example, a protocol version 0 (PV-0) MPDU, a
PV-1 MPDU, a PS-Poll, a NDP PS-Poll, and the like. A PV-0 MPDU is
an MPDU that has protocol version (PV) value that equals 0 and a
PV-1 MPDU is an MPDU that has protocol version value that equals 1.
In some embodiments, the difference between a PV-0 and a PV-1 MPDU
is that a PV-1 MPDU does not have a duration field and has shorter
header, while a PV-0 MPDU does have a duration field and longer
header. FIGS. 19 and 20 illustrate examples of a 1 MHz NDP ACK
frame and a NDP ACK frame that has a bandwidth greater than or
equal to 2 MHz, and are discussed below.
[0156] In another embodiment, another type of NDP ACK frame
includes a NDP Modified ACK that may be sent in response to a NDP
PS-Poll. For example, the NDP Modified ACK may be sent only in
response to received NDP PS-Polls. FIGS. 21 and 22 illustrate
examples of a 1 MHz NDP Modified ACK frame and a NDP Modified ACK
frame that has a bandwidth greater than or equal to 2 MHz, and are
discussed below.
[0157] FIG. 19 illustrates an example of a 1 MHz NDP ACK frame 1900
according to the teachings herein. As shown, the NDP ACK frame 1900
includes a type field, an ACK identifier (ACK ID) field, a more
data field, a duration indication field, a duration field, and a
relayed frame field. As one example, the type field includes 3
bits, the ACK ID field includes 9 bits, the more data field
includes 1 bit, the duration indication field includes 1 bit, the
duration field includes 10 bits, and the relayed frame field
includes 1 bit. One of skill in the art will appreciate that each
of the fields may include other appropriate bit values. In some
embodiments, the type field identifies the type of the control
frame and the ACK ID may be used to identify the frame. The more
data field may be used to indicates to the recipient of the frame
that at least one frame is available to the recipient. In some
embodiments, the duration field may be used to set or update a
network allocation vector (NAV).
[0158] FIG. 20 illustrates an example of a NDP ACK frame 2000 that
has a bandwidth greater than or equal to 2 MHz according to the
teachings herein. As shown, the NDP ACK frame 2000 includes a type
field, an ACK ID field, a more data field, a duration indication
field, a duration field, a relayed frame field, and a reserved
field. As one example, the type field includes 3 bits, the ACK ID
field includes 16 bits, the more data field includes 1 bit, the
duration indication field includes 1 bit, the duration field
includes 14 bits, the relayed frame field includes 1 bit, and the
reserved field includes 1 bit.
[0159] FIG. 21 illustrates an example of a 1 MHz NDP Modified ACK
frame 2100 according to the teachings herein. As shown, the NDP
Modified ACK frame 2100 includes a type field, an ACK ID field, a
more data field, a duration indication field, a duration field, and
a reserved field. As one example, the type field includes 3 bits,
the ACK ID field includes 9 bits, the more data field includes 1
bit, the duration indication field includes 1 bit, the duration
field includes 10 bits, and the reserved field includes 1 bit. The
NDP Modified ACK 2100 may be sent only in response to received NDP
PS-Polls that in one embodiment do not set the network allocation
vector (NAV).
[0160] FIG. 22 illustrates an example of a NDP Modified ACK frame
2200 that has a bandwidth greater than or equal to 2 MHz according
to the teachings herein. As shown, the NDP Modified ACK frame 2200
includes a type field, an ACK ID field, a more data field, a
duration indication field, a duration field, and a reserved field.
As one example, the type field includes 3 bits, the ACK ID field
includes 16 bits, the more data field includes 1 bit, the duration
indication field includes 1 bit, the duration field includes 14
bits, and the reserved field includes 2 bits.
[0161] Various issues may arise with the NDP ACK frames 1900, 2000
and the NDP Modified ACK frames 2100, 2200. For example, allocation
of 9 bits for the ACK ID of the 1 MHz NDP ACK frame 1900 may not be
enough bits to properly identify the frame.
[0162] In some embodiments, the NDP ACK frame and the NDP modified
ACK frame may be unified in order to overcome the above issues.
FIGS. 23 and 24 illustrate examples of a 1 MHz NDP ACK frame and a
NDP ACK frame that has a bandwidth greater than or equal to 2 MHz
that unify the NDP ACK frame and the NDP modified ACK frame. FIG.
23 illustrates an example of a unified 1 MHz NDP ACK frame 2300
according to the teachings herein. FIG. 24 illustrates an example
of a unified NDP ACK frame 2400) that has a bandwidth greater than
or equal to 2 MHz according to the teachings herein. As shown, the
unified 1 MHz NDP ACK frame 2300 and the unified NDP ACK frame 2400
that has a bandwidth greater than or equal to 2 MHz include a type
field, an ACK ID field, a duration field, a duration indication
field, a more data field, and a relayed frame field. As one
example, the unified 1 MHz NDP ACK frame 2300 includes a type field
including 3 bits, an ACK ID field including 9 bits, a duration
field including 10 bits, a duration indication including 1 bit, a
more data field including 1 bit, and a relayed frame field
including 1 bit. As another example, the unified NDP ACK frame 2400
that has a bandwidth greater than or equal to 2 MHz includes a type
field including 3 bits, an ACK ID field including 16 bits, a
duration field including 14 bits, a duration indication including 1
bit, a more data field including 1 bit, and a relayed frame field
including 1 bit.
[0163] In one embodiment, certain combinations of the NDP ACK frame
may be used to signal certain information to the intended receiver.
As an example, a device that is an AP can indicate to an intended
STA to not transmit UL data frames to the AP for a given time
interval which is specified in a duration field by setting the
relayed frame bit to 1 and the duration indication to 1. This
particular indication (jointly setting the relayed frame bit to 1
and the duration indication to 1) specifies that the receiving STA
(and eventually all STAs associated to the AP or Relay AP) shall
not transmit any UL data to the device they are associated to and
sent this NDP ACK for the time period specified in the duration
field of the NDP ACK. In general, any combination of some or all of
the fields in the NDP ACK may be used to signal a certain condition
that the device AP or relay requests its associated STAs to not
access the medium for the duration of time indicated in the
duration field.
[0164] In some embodiments, the ACK ID may be calculated based on a
partial FCS of the soliciting frame. In some embodiments, the ACK
ID may be calculated based on a scrambler seed of the soliciting
frame. In some embodiments, the ACK ID may be calculated based on
the PBSSID, PAID, and CRC for a NDP PS-Poll.
[0165] The duration indication field may be used to indicate
whether a NAV is present. Based on the value of the duration
indication field, the duration may be either a NAV value of a
non-NAV value. In one example of a 1 MHz NDP ACK frame where a NAV
value is used for the duration field, the NAV value may be up to
20.4 ms with a time unit (TU) equal to a short inter-frame space
(SIFS). A SIFS is the time interval between a frame and an
acknowledgement for that frame. In one example of a 2 MHz or
greater NDP ACK frame where a NAV value is used, the NAV value may
be up to 20.4 ms with a TU equal to a symbol.
[0166] In one example where a non-NAV value is used for the
duration field, a sleep duration may be used for the duration
field. For example, a sleep duration value may be included in the
duration field for NDP PS-Polls, and may be up to 127 ms for a 1
MHz frame and up to 511 ms for a frame that has a bandwidth greater
than or equal to 2 MHz, with a TU of 1 ms. In another example where
a non-NAV value is used for the duration field, an ID Extension may
be included in the duration field. For example, an STA interested
in a longer ID may negotiate the usage of the duration field to
extend its ID. If the duration indication does not indicate a NAV,
the duration field will be of no interest to third party STAs.
[0167] In some embodiments, in order to overcome the above issues
related to the ACK frames of FIGS. 19-22, one type of ACK frame may
be used to respond to all frames that set a NAV (a NDP NAV ACK),
and another type of ACK frame may be used to respond to all frames
that do not set a NAV (a NDP ID Extension (IDE) ACK).
[0168] FIGS. 25 and 26 illustrate examples of a 1 MHz NDP NAV ACK
frame 2500 and a NDP NAV ACK frame 2600 that has a bandwidth
greater than or equal to 2 MHz that may be used to respond to all
frames that set a NAV. As shown, the 1 MHz NDP ACK frame 2500 and
the NDP ACK frame 2600 that has a bandwidth greater than or equal
to 2 MHz include a type field, an ACK ID field, a duration field, a
more data field, and a relayed frame field. As one example, the 1
MHz NDP NAV ACK frame 2500 includes a type field including 3 bits,
an ACK ID field including 12 bits, a duration field including 8
bits, a more data field including 1 bit, and a relayed frame field
including 1 bit. As another example, the NDP NAV ACK frame 2600
that has a bandwidth greater than or equal to 2 MHz includes a type
field including 3 bits, an ACK ID field including 22 bits, a
duration field including 9 bits, a more data field including 1 bit,
and a relayed frame field including 1 bit. The value of the NAV
duration field may be up to 20.4 ms with a TU of 80 .mu.s for 1 MHz
and a TU of 40 .mu.s for a NDP ACK frame that has a bandwidth
greater than or equal to 2 MHz.
[0169] FIGS. 27 and 28 illustrate examples of a 1 MHz NDP IDE ACK
frame 2700 and a NDP IDE ACK frame 2800 that has a bandwidth
greater than or equal to 2 MHz that may be used to respond to all
frames that do not set a NAV. As shown, the 1 MHz and the 2 MHz or
greater NDP ACK frames 2700 and 2800 include a type field, an ACK
ID field, a sleep duration/ID extension (SDU/IDE) field, a more
data field, and a relayed frame field. As one example, the 1 MHz
NDP IDE ACK frame 2700 includes a type field including 3 bits, an
ACK ID field including 12 bits, a SDU/IDE field including 8 bits, a
more data field including 1 bit, and a relayed frame field
including 1 bit. As another example, the 2 MHz or greater NDP IDE
ACK frame 2800 includes a type field including 3 bits, an ACK ID
field including 22 bits, a SDU/IDE field including 9 bits, a more
data field including 1 bit, and a relayed frame field including 1
bit. The SDU/IDE field can be either a sleep duration (SDU) or an
ID extension (IDE), depending on the type of received frame. For
example, if the received frame is a PS-Poll, the SDU/IDE field may
include a SDU. In some embodiments, the value of the SDU in the
SDU/IDE field may be up to 255 ms for 1 MHz and up to 511 ms for a
NDP IDE ACK frame that has a bandwidth greater than or equal to 2
MHz, both with a TU of 1 ms. As another example, if the received
frame is a frame other than a PS-Poll, the SDU/IDE field may
include an ID extension. An STA interested in a longer ID may
negotiate usage of the SDU/IDE field to extend the STA's ID.
[0170] Accordingly, the ACK frames of FIGS. 23-28 may be used to
overcome the issues relating to the ACK frames of FIGS. 19-23. For
example, more than 9 bits are used for the ACK ID of each of the
frames. As another example, NAV is supported for all ACKs that
relate to MPDUs that set the NAV.
[0171] As described above, each of the control frames include a
type field. The type of control frame may be identified using a
type field value from, for example, 0 to 7. In some embodiments,
the value of the type field for each type of control frame may be
randomly assigned. However, randomly assigning to type field value
may lead to cross-type false positives. In some embodiments, the
type field values for control frames may be efficiently assigned
based on the type of frame so that values should have maximum
hamming distance to minimize cross-type false positives. For
example, a control frame may be generated comprising a type value
that is a maximum hamming distance from one or more type values of
one or more other control frames. A hamming distance as used herein
refers to the number of bits that are different between the values
of two control frame. For example, the hamming distance between 000
and 011 is a distance of 2 because two of the three bits are
different (the 2 least significant bits).
[0172] In some embodiments, if two types of frames are used, the
maximum Hamming distance will be 3. For example, the type value of
one control frame may be 000 and the type value of the other
control frame may be 111, and 000 and 111 have a hamming distance
of 3. In some embodiments, if four types of frames are used, the
maximum Hamming distance will be 2. For example, the type value of
a first control frame may be 000, the type value of a second
control frame may be 011, the type value of a third control frame
may be 101, and the type value of a fourth control frame may be
110, which all have a hamming distance of 2.
[0173] The control frames may include any of the control frames
discussed above, such as a CTS frame, a NDP ACK frame, a NDP
Modified ACK frame, a NDP block ACK frame, a unified 1 MHz NDP ACK
frame or a NDP ACK frame greater than or equal to 2 MHz, a 1 MHz
NDP NAV ACK frame or a NDP NAV ACK frame greater than or equal to 2
MHz, or a 1 MHz NDP IDE ACK frame or a NDP IDE ACK frame greater
than or equal to 2 MHz. For example, if a CTS frame, a NDP ACK
frame, a NDP Modified ACK frame, and a NDP block ACK frame are
used, then values may be assigned to the type field of each frame
so that a maximum hamming distance of 2 is achieved. In this
example, the CTS frame may have a type field value of 000, the NDP
ACK frame may have a type field value of 011, the NDP Modified ACK
frame may have a type field value of 101, and the NDP block ACK
frame may have a type field value of 110.
[0174] FIG. 29 shows a flow chart of an aspect of an exemplary
method 2900 of wireless communication. The method 2900 may be used
to assign the type field values described above. Although the
method 2900 is described below with respect to elements of the
wireless device 202 (FIG. 2), those having ordinary skill in the
art will appreciate that other components may be used to implement
one or more of the steps described herein. Although blocks may be
described as occurring in a certain order, the blocks can be
reordered, blocks can be omitted, and/or additional blocks can be
added.
[0175] At block 2902, the method 2900 begins by generating a
control frame comprising a contention free end (CF-end) frame, the
CF-end frame comprising a physical layer preamble having a type
field, the type field including an indicator indicating the CF-end
frame is a null data packet (NDP). In some aspects, the CF-end
frame may comprise a type field indicating an NDP type and a
subtype field differentiating between a CF-end and a clear to send
(CTS) subtype. At block 2904, the method 2900 continues by
transmitting the control frame.
[0176] FIG. 30 shows a flow chart of an aspect of an exemplary
method 3000 of wireless communication. The method 3000 may be used
to assign the type field values described above. Although the
method 3000 is described below with respect to elements of the
wireless device 202 (FIG. 2), those having ordinary skill in the
art will appreciate that other components may be used to implement
one or more of the steps described herein. Although blocks may be
described as occurring in a certain order, the blocks can be
reordered, blocks can be omitted, and/or additional blocks can be
added.
[0177] At block 3002, the method 3000 begins by generating a
control frame comprising a null data packet acknowledgement (NDP
ACK) frame or NDP modified ACK frame, the NDP ACK frame or NDP
modified ACK frame comprising a duration indication field, wherein
the duration indication field provides signaling information for
the NDP ACK or the NDP modified ACK. In some aspects, the NDP ACK
frame or NDP modified ACK frame further comprises a NDP frame type
field, an identifier field, a duration field, and a field for
storing additional data. At block 3004, the method 3000 continues
by transmitting the control frame.
[0178] FIG. 31 is a functional block diagram of an exemplary
wireless device 3100 that may be employed within the wireless
communication system 100. The device 3100 comprises a generating
module 3102 for generating a control frame comprising a contention
free end (CF-end) frame, the CF-end frame comprising a physical
layer preamble having a type field, the type field including an
indicator indicating the CF-end frame is a null data packet (NDP).
The generating module 3102 may also generate a control frame
comprising a null data packet acknowledgement (NDP ACK) frame or
NDP modified ACK frame, the NDP ACK frame or NDP modified ACK frame
comprising a duration indication field, wherein the duration
indication field provides signaling information for the NDP ACK or
the NDP modified ACK
[0179] The generating module 3102 may be configured to perform one
or more of the functions discussed above with respect to the block
2902 illustrated in FIG. 29 or with respect to the block 3002
illustrated in FIG. 30. The generating module 3102 may correspond
to the processor 204, the memory 206, and/or the DSP 220. The
device 3100 further comprises a transmitting module 3104 for
processing the control frame. The transmitting module 3104 may be
configured to perform one or more of the functions discussed above
with respect to the block 2904 illustrated in FIG. 29 or with
respect to the block 3004 illustrated in FIG. 30. The transmitting
module 3104 may correspond to one or more of the transmitter 210 or
the transceiver 214.
[0180] As used herein, the term "determining" encompasses a wide
variety of actions. For example, "determining" may include
calculating, computing, processing, deriving, investigating,
looking up (e.g., looking up in a table, a database or another data
structure), ascertaining and the like. Also, "determining" may
include receiving (e.g., receiving information), accessing (e.g.,
accessing data in a memory) and the like. Also, "determining" may
include resolving, selecting, choosing, establishing and the like.
Further, a "channel width" as used herein may encompass or may also
be referred to as a bandwidth in certain aspects.
[0181] As used herein, a phrase referring to "at least one of" a
list of items refers to any combination of those items, including
single members. As an example, "at least one of: a, b, or c" is
intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.
[0182] The various operations of methods described above may be
performed by any suitable means capable of performing the
operations, such as various hardware and/or software component(s),
circuits, and/or module(s). Generally, any operations illustrated
in the Figures may be performed by corresponding functional means
capable of performing the operations.
[0183] The various illustrative logical blocks, modules and
circuits described in connection with the present disclosure may be
implemented or performed with a general purpose processor, a
digital signal processor (DSP), an application specific integrated
circuit (ASIC), a field programmable gate array signal (FPGA) or
other programmable logic device (PLD), discrete gate or transistor
logic, discrete hardware components or any combination thereof
designed to perform the functions described herein. A general
purpose processor may be a microprocessor, but in the alternative,
the processor may be any commercially available processor,
controller, microcontroller or state machine. A processor may also
be implemented as a combination of computing devices, e.g., a
combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration.
[0184] In one or more aspects, the functions described may be
implemented in hardware, software, firmware, or any combination
thereof. If implemented in software, the functions may be stored on
or transmitted over as one or more instructions or code on a
computer-readable medium. Computer-readable media includes both
computer storage media and communication media including any medium
that facilitates transfer of a computer program from one place to
another. A storage media may be any available media that can be
accessed by a computer. By way of example, and not limitation, such
computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or
other optical disk storage, magnetic disk storage or other magnetic
storage devices, or any other medium that can be used to carry or
store desired program code in the form of instructions or data
structures and that can be accessed by a computer. Also, any
connection is properly termed a computer-readable medium. For
example, if the software is transmitted from a website, server, or
other remote source using a coaxial cable, fiber optic cable,
twisted pair, digital subscriber line (DSL), or wireless
technologies such as infrared, radio, and microwave, then the
coaxial cable, fiber optic cable, twisted pair, DSL, or wireless
technologies such as infrared, radio, and microwave are included in
the definition of medium. Disk and disc, as used herein, includes
compact disc (CD), laser disc, optical disc, digital versatile disc
(DVD), floppy disk and blu-ray disc where disks usually reproduce
data magnetically, while discs reproduce data optically with
lasers. Thus, in some aspects, computer readable medium may
comprise non-transitory computer readable medium (e.g., tangible
media). In addition, in some aspects, computer readable medium may
comprise transitory computer readable medium (e.g., a signal).
Combinations of the above should also be included within the scope
of computer-readable media.
[0185] The methods disclosed herein comprise one or more steps or
actions for achieving the described method. The method steps and/or
actions may be interchanged with one another without departing from
the scope of the claims. In other words, unless a specific order of
steps or actions is specified, the order and/or use of specific
steps and/or actions may be modified without departing from the
scope of the claims.
[0186] The functions described may be implemented in hardware,
software, firmware or any combination thereof. If implemented in
software, the functions may be stored as one or more instructions
on a computer-readable medium. A storage media may be any available
media that can be accessed by a computer. By way of example, and
not limitation, such computer-readable media can comprise RAM, ROM,
EEPROM, CD-ROM or other optical disk storage, magnetic disk storage
or other magnetic storage devices, or any other medium that can be
used to carry or store desired program code in the form of
instructions or data structures and that can be accessed by a
computer. Disk and disc, as used herein, include compact disc (CD),
laser disc, optical disc, digital versatile disc (DVD), floppy
disk, and Blu-ray disc where disks usually reproduce data
magnetically, while discs reproduce data optically with lasers.
[0187] Thus, certain aspects may comprise a computer program
product for performing the operations presented herein. For
example, such a computer program product may comprise a computer
readable medium having instructions stored (and/or encoded)
thereon, the instructions being executable by one or more
processors to perform the operations described herein. For certain
aspects, the computer program product may include packaging
material.
[0188] Software or instructions may also be transmitted over a
transmission medium. For example, if the software is transmitted
from a website, server, or other remote source using a coaxial
cable, fiber optic cable, twisted pair, digital subscriber line
(DSL), or wireless technologies such as infrared, radio, and
microwave, then the coaxial cable, fiber optic cable, twisted pair,
DSL, or wireless technologies such as infrared, radio, and
microwave are included in the definition of transmission
medium.
[0189] Further, it should be appreciated that modules and/or other
appropriate means for performing the methods and techniques
described herein can be downloaded and/or otherwise obtained by a
user terminal and/or base station as applicable. For example, such
a device can be coupled to a server to facilitate the transfer of
means for performing the methods described herein. Alternatively,
various methods described herein can be provided via storage means
(e.g., RAM, ROM, a physical storage medium such as a compact disc
(CD) or floppy disk, etc.), such that a user terminal and/or base
station can obtain the various methods upon coupling or providing
the storage means to the device. Moreover, any other suitable
technique for providing the methods and techniques described herein
to a device can be utilized.
[0190] It is to be understood that the claims are not limited to
the precise configuration and components illustrated above. Various
modifications, changes and variations may be made in the
arrangement, operation and details of the methods and apparatus
described above without departing from the scope of the claims.
[0191] While the foregoing is directed to aspects of the present
disclosure, other and further aspects of the disclosure may be
devised without departing from the basic scope thereof, and the
scope thereof is determined by the claims that follow.
* * * * *