U.S. patent application number 12/396834 was filed with the patent office on 2010-09-09 for beaconing mode for wireless communication.
This patent application is currently assigned to NOKIA CORPORATION. Invention is credited to Mika KASSLIN, Kari Leppanen, Mikko Tirronen, Sami Virtanen.
Application Number | 20100226309 12/396834 |
Document ID | / |
Family ID | 42678201 |
Filed Date | 2010-09-09 |
United States Patent
Application |
20100226309 |
Kind Code |
A1 |
KASSLIN; Mika ; et
al. |
September 9, 2010 |
BEACONING MODE FOR WIRELESS COMMUNICATION
Abstract
Embodiments of the present invention are directed to
facilitating apparatus interaction. In at least one example
embodiment of the present invention, apparatuses may comprise both
triggered communication activities and automated communication
activities. Triggered communication activities may correspond to,
for example, user and/or application instigated actions in a
wireless apparatus. Automated activities may occur without any
requirement for user intervention, and further, without any
notification to the user that an action has occurred.
Inventors: |
KASSLIN; Mika; (Espoo,
FI) ; Tirronen; Mikko; (Helsinki, FI) ;
Leppanen; Kari; (Helsinki, FI) ; Virtanen; Sami;
(Espoo, FI) |
Correspondence
Address: |
Locke Lord Bissell & Liddell LLP;Attn: IP Docketing
Three World Financial Center
New York
NY
10281-2101
US
|
Assignee: |
NOKIA CORPORATION
Espoo
FI
|
Family ID: |
42678201 |
Appl. No.: |
12/396834 |
Filed: |
March 3, 2009 |
Current U.S.
Class: |
370/328 |
Current CPC
Class: |
H04W 40/244 20130101;
H04W 56/001 20130101; H04W 48/12 20130101 |
Class at
Publication: |
370/328 |
International
Class: |
H04W 4/00 20090101
H04W004/00 |
Claims
1. A method, comprising: receiving a beacon frame comprising a
timing signal, an associated beacon period indication and an
associated diluted beacon period indication corresponding to a
wireless network; synchronizing a timing signal function to the
received beacon timing signal; and determining a mode of operation
based on the timing signal function, the beacon period indication
and the diluted beacon period indication.
2. The method of claim 1, wherein the associated diluted beacon
period is communicated in the beacon frame in a predefined
information element.
3. The method of claim 1, wherein the associated diluted beacon
period is associated with the beacon period in that it is a
multiple of the beacon period.
4. The method of claim 1, wherein determining a mode of operation
based on the timing signal function, the beacon period indication
and the diluted beacon period indication comprises selecting
whether to be active in the network according to the timing signal
or the diluted beacon period.
5. The method of claim 4, wherein being active in the network
comprises contending for access to a wireless communication medium
with other networked apparatuses.
6. The method of claim 1, further comprising communicating the
determined mode of operation to other networked apparatuses.
7. A method, comprising: initiating a wireless network; and
transmitting one or more beacon frames, the beacon frames including
a timing signal, an associated beacon period indication and an
associated diluted beacon period indication corresponding to the
wireless network.
8. The method of claim 7, wherein the associated diluted beacon
period is associated with the beacon period in that it is a
multiple of the beacon period.
9. A computer program product comprising computer executable
program code recorded on a computer readable medium, comprising:
computer program code configured to receive a beacon frame
comprising a timing signal, an associated beacon period indication
and an associated diluted beacon period indication corresponding to
a wireless network; computer program code configured to synchronize
a timing signal function to the received beacon timing signal; and
computer program code configured to determine a mode of operation
based on the timing signal function, the beacon period indication
and the diluted beacon period indication.
10. The computer program product of claim 9, wherein the associated
diluted beacon period is communicated in the beacon frame in a
predefined information element.
11. The computer program product of claim 9, wherein the associated
diluted beacon period is associated with the beacon period in that
it is a multiple of the beacon period.
12. The computer program product of claim 9, wherein determining a
mode of operation based on the timing signal function, the beacon
period indication and the diluted beacon period indication
comprises selecting whether to be active in the network according
to the timing signal or the diluted beacon period.
13. The computer program product of claim 12, wherein being active
in the network comprises contending for access to a wireless
communication medium with other networked apparatuses.
14. The computer program product of claim 9, further comprising
communicating the determined mode of operation to other networked
apparatuses.
15. A computer program product comprising computer executable
program code recorded on a computer readable medium, comprising:
computer program code configured to initiate a wireless network;
and computer program code configured to transmit one or more beacon
frames, the beacon frames including a timing signal, an associated
beacon period indication and an associated diluted beacon period
indication corresponding to the wireless network.
16. The computer program product of claim 15, wherein the
associated diluted beacon period is associated with the beacon
period in that it is a multiple of the beacon period.
17. An apparatus, comprising: a processor, the processor being
configured to: receive a beacon frame comprising a timing signal,
an associated beacon period indication and an associated diluted
beacon period indication corresponding to a wireless network;
synchronize a timing signal function to the received beacon timing
signal; and determine a mode of operation based on the timing
signal function, the beacon period indication and the diluted
beacon period indication.
18. The apparatus of claim 17, wherein the associated diluted
beacon period is communicated in the beacon frame in a predefined
information element.
19. The apparatus of claim 17, wherein the associated diluted
beacon period is associated with the beacon period in that it is a
multiple of the beacon period.
20. The apparatus of claim 17, wherein determining a mode of
operation based on the timing signal function, the beacon period
indication and the diluted beacon period indication comprises
selecting whether to be active in the network according to the
timing signal or the diluted beacon period.
21. The apparatus of claim 20, wherein being active in the network
comprises contending for access to a wireless communication medium
with other networked apparatuses.
22. The apparatus of claim 17, further comprising communicating the
determined mode of operation to other networked apparatuses.
23. An apparatus, comprising: A processor, the processor being
configured to: initiate a wireless network; and transmit one or
more beacon frames, the beacon frames including a timing signal, an
associated beacon period indication and an associated diluted
beacon period indication corresponding to the wireless network.
24. The apparatus of claim 23, wherein the associated diluted
beacon period is associated with the beacon period in that it is a
multiple of the beacon period.
Description
BACKGROUND
[0001] 1. Field of Invention
[0002] Various embodiments of the present invention pertain
generally to wireless link establishment, and in particular, to
establishing beacon periods of varying frequency.
[0003] 2. Background
[0004] Wireless communication has moved from simply being concerned
with conveying verbal information to being more focused on total
digital interactivity. While originally limited to voice
communication (e.g., telephone calls on cellular handsets),
enhancements in wireless technology have substantially improved
ability, quality of service (QoS), speed, etc. These developments
have contributed to an insatiable desire for new functionality.
Portable wireless apparatuses are no longer just tasked with making
telephone calls. They have become integral, and in some cases
essential, tools for managing the professional and/or personal life
of users.
[0005] The effect of this evolving technology may be seen in
instances where a plurality of apparatuses have been replaced with
a single multifunction device. The functionality that was formally
provided by landline telephones and facsimiles, laptop computers,
portable digital assistants (PDA), game systems, music players,
digital storage devices may be supported in a single digital
communication apparatus. The above functionality may be further
supplemented through the provision of applications that were not
previously available in portable apparatuses (e.g.,
directional/tracking features, wireless financial transactions,
social networking, etc.).
[0006] Such functionality, both existing and emerging, require
systems and strategies for seamlessly interconnecting users. In
particular, apparatus users will desire a virtually immediate
response when applications or functions are executed. Any delay or
inaccuracy in the response will negatively impact on a user's
satisfaction with the application or function, and thus, may be
detrimental to the acceptance of the application or function by the
consuming public.
SUMMARY
[0007] Example embodiments of the present invention may be directed
to a method, apparatus, computer program and system for
facilitating apparatus interaction. In accordance with at least one
example implementation, apparatuses operating within communication
range of each other (e.g., in the same operational space) may
interact wirelessly without user intervention. This interaction may
comprise data-type information exchanges conducted over distributed
local networks. Distributed local networks may establish/maintain
connectivity between apparatuses without visibility from the
user/application level through the use of simple low-level
messaging.
[0008] In accordance with various example embodiments of the
present invention, network connections may be established in
accordance with protocols dictated by the particular wireless
communication medium being employed. In some instances, apparatuses
participating in these networks may be kept in synchronization
through the use of beaconing. While a beacon may establish timing
for the entire network, certain apparatuses may desire (or may be
required) to be active less frequently than dictated by network
beaconing. For example, apparatuses with limited resources, low
messaging levels, etc. may have activity requirements substantially
below the frequency established by the beacon. These apparatuses
may select an operational mode that uses a beacon period that is
lower than the standard beacon period, or a "diluted" beacon
period.
[0009] In at least one implementation, beaconing apparatuses may
also transmit one or more associated diluted beacon period
indications in each beacon frame. Diluted beacon period indications
may be communicated in terms of predefined information elements
(IEs), and may be "associated" with a beacon in that the frequency
of a diluted beacon may be expressed as a multiple of the primary
beaconing period. Since diluted beacon periods are defined by the
apparatus transmitting the network beacon, the operational mode of
apparatuses that join the network may be established after beacon
synchronization, and may further be communicated within the network
so that periods where apparatuses may be contending for access to a
wireless communication medium may be known to the other networked
apparatuses.
[0010] The above summarized configurations or operations of various
embodiments of the present invention have been provided merely for
the sake of explanation, and therefore, are not intended to be
limiting. Moreover, inventive elements associated herein with a
particular example embodiment of the present invention can be used
interchangeably with other example embodiments depending, for
example, on the manner in which an embodiment is implemented.
DESCRIPTION OF DRAWINGS
[0011] The disclosure will be further understood from the following
description of various exemplary embodiments, taken in conjunction
with appended drawings, in which:
[0012] FIG. 1 discloses examples of hardware and software resources
that may be utilized when implementing various example embodiments
of the present invention.
[0013] FIG. 2 discloses an example network environment in
accordance with at least one example embodiment of the present
invention.
[0014] FIG. 3 discloses examples of various types of messaging that
may be utilized in accordance with at least one example embodiment
of the present invention.
[0015] FIG. 4 discloses an example of message propagation that may
result in distributed local web formation in accordance with at
least one example embodiment of the present invention.
[0016] FIG. 5 discloses example beacon implementations that are
usable in accordance with at least one example embodiment of the
present invention.
[0017] FIG. 6 discloses an example of host responsibilities and
modem responsibilities in accordance with at least one example
embodiment of the present invention.
[0018] FIG. 7 discloses examples of various packet structures in
accordance with at least one example embodiment of the present
invention.
[0019] FIG. 8 discloses a flowchart for an example communication
process in accordance with at least one example embodiment of the
present invention.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0020] While the present invention has been described herein in
terms of a multitude of example embodiments, various changes or
alterations can be made therein without departing from the spirit
and scope of the present invention, as set forth in the appended
claims.
I. General System with which Embodiments of the Present Invention
may be Implemented
[0021] An example of a system that is usable for implementing
various embodiments of the present invention is disclosed in FIG.
1. The system comprises elements that may be included in, or
omitted from, configurations depending, for example, on the
requirements of a particular application, and therefore, is not
intended to limit present invention in any manner.
[0022] Computing device 100 may be, for example, a laptop computer.
Elements that represent basic example components comprising
functional elements in computing device 100 are disclosed at
102-108. Processor 102 may include one or more devices configured
to execute instructions, wherein a group of instructions may be
constituted, for example, as program code. In at least one
scenario, the execution of program code may include receiving input
information from other elements in computing device 100 in order to
formulate an output (e.g., data, event, activity, etc). Processor
102 may be a dedicated (e.g., monolithic) microprocessor device, or
may be part of a composite device such as an ASIC, gate array,
multi-chip module (MCM), etc.
[0023] Processor 102 may be electronically coupled to other
functional components in computing device 100 via a wired or
wireless bus. For example, processor 102 may access memory 102 in
order to obtain stored information (e.g., program code, data, etc.)
for use during processing. Memory 104 may generally include
removable or imbedded memories that operate in a static or dynamic
mode. Further, memory 104 may include read only memories (ROM),
random access memories (RAM), and rewritable memories such as
Flash, EPROM, etc. Code may include any interpreted or compiled
computer language including computer-executable instructions. The
code and/or data may be used to create software modules such as
operating systems, communication utilities, user interfaces, more
specialized program modules, etc.
[0024] One or more interfaces 106 may also be coupled to various
components in computing device 100. These interfaces may allow for
inter-apparatus communication (e.g., a software or protocol
interface), apparatus-to-apparatus communication (e.g., a wired or
wireless communication interface) and even apparatus to user
communication (e.g., a user interface). These interfaces allow
components within computing device 100, other apparatuses and users
to interact with computing device 100. Further, interfaces 106 may
communicate machine-readable data, such as electronic, magnetic or
optical signals embodied on a computer readable medium, or may
translate the actions of users into activity that may be understood
by computing device 100 (e.g., typing on a keyboard, speaking into
the receiver of a cellular handset, touching an icon on a touch
screen device, etc.) Interfaces 106 may further allow processor 102
and/or memory 104 to interact with other modules 108. For example,
other modules 108 may comprise one or more components supporting
more specialized functionality provided by computing device
100.
[0025] Computing device 100 may interact with other apparatuses via
various networks as further shown in FIG. 1. For example, hub 100
may provide wired and/or wireless support to devices such as
computer 114 and server 116. Hub 100 may be further coupled to
router 112 that allows devices on the local area network (LAN) to
interact with devices on a wide area network (WAN, such as Internet
120). In such a scenario, another router 130 may transmit
information to, and receive information from, router 112 so that
devices on each LAN may communicate. Further, all of the components
depicted in this example configuration are not necessary for
implementation of the present invention. For example, in the LAN
serviced by router 130 no additional hub is needed since this
functionality may be supported by the router.
[0026] Further, interaction with remote devices may be supported by
various providers of short and long range wireless communication
140. These providers may use, for example, long range
terrestrial-based cellular systems and satellite communication,
and/or short-range wireless access points in order to provide a
wireless connection to Internet 120. For example, personal digital
assistant (PDA) 142 and cellular handset 144 may communicate with
computing device 100 via an Internet connection provided by a
provider of wireless communication 140. Similar functionality may
be included in devices, such as laptop computer 146, in the form of
hardware and/or software resources configured to allow short and/or
long range wireless communication.
II. Example Networking Environment
[0027] FIG. 2 discloses an example operational space that will be
utilized to describe various example embodiments of the present
invention. The example scenario depicted in FIG. 2 is utilized
herein only for the sake of explanation, and therefore, is not
intended to limit the scope of the various embodiments of the
present invention. Operational spaces may be defined using various
criteria. For example, a physical space like a building, theatre,
sports arena, etc. may be utilized to define an area in which users
interact. Otherwise, operational spaces may be defined in view of
apparatuses utilizing particular wireless transports, apparatuses
within communication range (e.g., a certain distance) of each
other, apparatuses that are in certain classes or groups, etc.
[0028] Wireless-enabled apparatuses 200 are labeled "A" to "G" in
FIG. 2. Apparatuses 200 may, for example, correspond to any of the
wireless-enabled apparatuses that were disclosed in FIG. 1, and may
further include at least the resources discussed with respect to
apparatus 100. For the sake of example herein, these apparatuses
may operate utilizing at least one wireless communication medium in
common. That is, all apparatuses in the example of FIG. 2 are at
least able to wirelessly communicate with each other within the
operational space, and therefore, may participate in the same
wireless communication network.
III. Examples of Messaging
[0029] Now referring to FIG. 3, an example of communication between
apparatuses in accordance with at least one example embodiment of
the present invention is disclosed at 300. While only apparatus
200A and apparatus 200B are shown, the disclosed example scenario
is being utilized only for the sake of explanation herein, and is
not intended to limit the scope or applicability of any embodiment
of the present invention. Moreover, the various example embodiments
of the present invention, such as disclosed herein, may be
implemented in order to facilitate wireless interaction between two
or more apparatuses existing in an operational space.
[0030] Additional detail with respect to communication example 300
is disclosed further in FIG. 3. Apparatus 200A may have
communication requirements that require interaction with apparatus
200B. For example, these requirements may comprise interactions by
apparatus users, applications residing on the apparatuses, etc.
that trigger the transmission of messages that may be generally
classified under the category of data-type communication 302.
Data-type communication may be carried out using tiny messages that
may be transmitted between apparatus 200A and 200B. However, some
form of wireless network link or connection must first be
established before any data type communication messages 302 may be
exchanged.
[0031] Network establishment and MAC management messages 304 may be
utilized to establish and maintain an underlying wireless network
architecture within an operating space that may be utilized to
convey data type communication messages 302. In accordance with
various example embodiments of the present invention, messages
containing apparatus configuration, operation and status
information may be exchanged to transparently establish wireless
network connections when, for example, an apparatus enters an
operating space. Network connections may exist between any or all
apparatuses existing within the operating space, and may be in
existence for the entire time that an apparatus resides in the
operating space. In this way, data-type communication messages 302
may be conveyed between apparatuses over already existent networks
(a new network connection does not need to be negotiated at the
time the message is to be sent), which may in turn reduce response
delay and increase quality of service (QoS).
[0032] The example scenario disclosed in FIG. 2 is now revisited in
FIG. 4, which shows an example of distributed local network
formation utilizing automated network establishment and MAC
management messages 304. Apparatuses 200 that enter into
operational space 210 may immediately begin to formulate network
connections through the exchange operational information. Again,
the exchange of this information may occur without any prompting
from, or even knowledge of, a user. An example of this
interactivity is shown in FIG. 4, wherein various network
establishment and MAC management messages 304 are exchanged between
apparatuses A to G. In accordance with at least one example
embodiment of the present invention, messages may be exchanged
directly between an originating apparatus (e.g., the apparatus that
is described by the information elements in a message) and a
receiving apparatus. Alternatively, messages corresponding to one
or more apparatuses in operational space 210 may be forwarded from
one apparatus to another, thereby disseminating the information for
multiple apparatuses.
IV. Example Operational Parameter: Diluted Beacon Period
[0033] An example of information that may be communicated in
network establishment and MAC management messages 304 (e.g.,
through the use in an information element) is now disclosed in FIG.
5. The activity flow disclosed at 500 represents an example
implementation using selected features of wireless local area
networking or WLAN (as set forth in the IEEE 802.11 specification).
However, various embodiments of the present invention are not
strictly limited to WLAN, and thus, may be applied to various
wireless network architectures using various wireless mediums.
[0034] The WLAN logical architecture comprises stations (STA),
wireless access points (AP), independent basic service sets (IBSS),
basic service sets (BSS), distribution systems (DS), and extended
service sets (ESS). Some of these components map directly to
hardware devices, such as stations and wireless access points. For
example wireless access points may function as bridges between
stations and a network backbone (e.g., in order to provide network
access). An independent basic service set is a wireless network
comprising at least two stations. Independent basic service sets
are also sometimes referred to as an ad hoc wireless network. Basic
service sets are wireless networks comprising a wireless access
point supporting one or multiple wireless clients. Basic service
sets are also sometimes referred to as infrastructure wireless
networks. All stations in a basic service set may interact through
the access point. Access points may provide connectivity to wired
local area networks and provides bridging functionality when one
station initiates communication to another station or with a node
in a distribution system (e.g., with a station coupled to another
access point that is linked through a wired network backbone).
[0035] In wireless network architectures like WLAN, beacon signals
may be utilized to synchronize the operation of networked
apparatuses. In situations where new ad hoc networks are being
created, the initiating apparatus may establish beaconing based on
it owns clock, and all apparatuses that join the network may
conform to this beacon. Similarly, apparatuses that desire to join
an existing wireless network may synchronize to the existing
beacon. In the case of WLAN, apparatuses may synchronize to beacon
signals utilizing a timing synchronization function (TSF). The
timing synchronization function is a clock function that is local
to an apparatus that synchronizes to and tracks the beacon
period.
[0036] An example of a beacon signal is shown in FIG. 5 at 502
wherein a target beacon transmission time (TBTT) indicates the
targeted beacon transmission. This time may be deemed "targeted"
because the actual beacon transmission may be a somewhat delayed
from the TBTT due to, for example, the channel being occupied at
TBTT. The apparatuses that are active in the network may
communicate with each other in accordance with the beacon period.
However, there may be instances where it may not be beneficial, and
may possibly even be detrimental, for apparatuses to be active
during each beacon period. For example, apparatuses that do not
expect frequent communication within the wireless network may not
benefit from being active for every beacon period. Moreover,
apparatuses with limited power or processing resource may be forced
to waste these precious resources by the requirement of being
active for every beacon period.
[0037] In accordance with at least one example embodiment of the
present invention, functionality may be introduced utilizing the
example distributed wireless network described above to allow
apparatuses to operate at a standard beaconing rate, or
alternatively, using a "diluted" beaconing rate. "Diluted"
beaconing may entail a beaconing mode operating at a lower
frequency than the beaconing rate originally established in the
network. Diluted beaconing may be based on information (e.g.,
information elements) that is included in network beacon frames,
wherein the included information may express one or more diluted
beacon rates as multiples of the beacon. Using the beacon and the
one or more associated diluted beacon period indications contained
within beacon frames, networked apparatuses may elect to operate
(e.g., via random contention) based either on the beacon or a
diluted beacon period. In particular, all apparatuses may
synchronize to the same initial target beacon transmission time
(TBTT), for example when TSF=0, and may then count the number
periods that occur after the initial TBTT based on the internal TSF
function. In this way, apparatuses operating using a diluted beacon
period may be active on TBTT counts that corresponds to the
multiple defined by the diluted beaconing period.
[0038] An example diluted beacon rate of every 10.sup.th TBTT is
disclosed in FIG. 5 at 504. The decision on a beaconing rate to
utilize may be handled by each apparatus individually, (e.g., in
the protocol stacks that manage operation of a radio modem). All
apparatuses, however, will operate based on a beacon interval that
remains the same for the lifetime of the network. In view of the
requirement that the beacon interval remain unchanged for the
duration of the wireless network, the diluted beacon signal may be
expressed as a multiple of the beacon signal. In the example
disclosed in FIG. 5, and as set forth above, the first TBTT is
equivalent TSF=0. This initial value is dictated by the apparatus
that formed the network. Other apparatuses that subsequently join
the network may adopt this beacon interval parameter and TBTT
timing. For example, the TBTT at TSF=0 is the "base point" that
determines when beacons are transmitted. All the devices in network
update their own TSF counters as per legacy synchronization rules,
and from the TSF they may determine the particular TBTT in which to
participate in beaconing assuming that, regardless of the beaconing
rate, the first beacon was transmitted at TSF=0.
[0039] For example, in a network with four apparatuses where
devices 1, 2 and 4 operate using a diluted beaconing mode having an
example frequency (e.g., a time period between beacon
transmissions) of every 6.sup.th TBTT all apparatuses may remain
synchronized, but only device 3 would be active (e.g., "competing")
in beaconing periods 1, 2, 3, 4 and 5, while all apparatuses may
participate in TBTT 0, TBTT 6, TBTT 12, etc. Therefore, there can
be at least two different beacon periods among the apparatuses, and
possibly further diluted beacon periods as each apparatus may
select its own diluted beaconing period based on the original
beaconing period and the one or more associated diluted beacon
period indications transmitted therewith.
[0040] In accordance with at least one example embodiment of the
present invention, beacons will contain a diluted beacon period
parameter. The diluted beacon period parameter may, for example, be
carried in vendor-specific information elements (IEs). Diluted
beacon period parameter values may remain the same for the lifetime
of the network. However, should there be need for more flexibility,
other beacon rate periods may be predefined, and all of the
predefined beacon rate periods may signaled in a manner similar to
the diluted beaconing rate.
[0041] FIG. 6 discloses an example of the responsibilities of host
600 (e.g., upper level control layers that reside above a radio
modem in apparatuses) and the responsibilities of radio modem 604.
The term "radio modem" in this instance may also be considered to
encompass more complex radio "modules" that incorporate additional
functionality into the radio modem. For example, host 600 may be
responsible for commands instructing a modem to start a network (or
to join a network) and the determination of whether to utilize a
beacon interval or diluted beacon period given to the modem. Host
600 may further be responsible for post-processing related to
received beacons, the formation of beacons for transmission by the
radio modem (e.g., when an apparatus is establishing a new
network), communicating with networked apparatuses using host-level
protocols (e.g., that exploit WLAN data type frames). Moreover,
beacon rate transition notifications (e.g., beacon rate changes
during the life of a network) can be conveyed in both beacons
(e.g., vendor-specific information elements) or in host-level
protocol messages.
[0042] Host-Modem Interface (I/F) 602 can be either a physical
interface between two physically separate entities, like a host
processor and wireless modem, or a logical (software) interface
inside one physical entity, like wireless modem, or may comprise
combinations of both.
[0043] The responsibilities of radio modem 604 may include, in the
instance of network establishment, determining the actual time of
the first TBTT (and subsequent TBTTs that are separated in
accordance with the beacon interval). Further radio modem 604 may
count the number TBTTs that have occurred, and may participate in
beaconing for every TBTT (e.g., standard beaconing) or every Nth
multiple of the TBTT (e.g., diluted beaconing) in accordance with
the configuration defined by host 600, may provide received beacon
signals to the host for post-processing and may transmit and
receive frames as in standard WLAN ad hoc networking.
[0044] Various example implementations of the present invention may
utilize "standard" beacon frame formats, such as disclosed at 700
in FIG. 7. The body of beacon frames contains a sequence of
information fields that may, for example, be dedicated for fixed
format fields (e.g., fields that are always fixed in the same
position of the frame), or information elements (IEs) that may be
the formatted as disclosed at 702 and 704. Beacon interval is a
dedicated fixed field that is used to indicate the number of time
units between TBTTs (e.g., as in the standard WLAN).
[0045] Beacons may also utilize vendor-specific information
elements to indicate diluted beacon period values. Per the example
disclosed at 706, the first three octets of the information field
may contain an organizationally unique identifier (OUI)
corresponding to manufacturers, vendors, service-providers, etc.
This OUI may further define the content of a particular vendor
specific information element. The OUI field may be publicly
available information that is assigned by an organization like the
Institute of Electrical and Electronics Engineers (IEEE). Such as
in the example disclosed at 708, a diluted beacon period can be
associated with its own OUI, or the OUI may correspond to, for
example, a device vendor or service provider specific OUI and
indication of diluted beacon period parameter is in the
vendor-specific content.
[0046] A flowchart of an example communication process in
accordance with at least one example embodiment of the present
invention is now described with respect to FIG. 8. In step 800
links between apparatuses may be created, for example, when
apparatuses enter into a particular area (e.g., an operational
space) that contains other wireless-enabled apparatuses. Linking
may comprise the establishment of new networks, or alternatively,
apparatuses joining existing networks. In situations where new
networks need to be established (e.g., as determined in step 802)
at least one apparatus may enter a new network creation mode in
step 804. The new network creation mode may comprise beacon
transmission wherein, in accordance with at least one embodiment of
the present invention, beacon frames may comprise a timing signal
and one or more associated diluted beacon indications. Apparatuses
may then participate in the network based on a particular
operational mode (in this example as beaconing apparatus) in step
806 until the network is discontinued as determined in step 808.
The process may then return to step 800 to await further
requirements for link establishment.
[0047] If an existing network to which membership is desired is
determined in step 802, then apparatus desiring network membership
may attempt to synchronize to the network beacon in step 810. For
example, an attempt may be made to synchronize the clock provided
by the timing synchronization function to the beacon. The timing
synchronization function allows network apparatuses to track the
beacon signal and keep synchronized with the other apparatuses in
the network. Upon synchronization, as determined in step 812,
control entities (e.g., host 600) in devices that desire network
membership may then determine an operational mode in step 814.
[0048] The criteria for selecting operational mode may be
determined in view of, for example, the activity in an apparatus
that necessitated the communication, current apparatus operating
condition, the abilities/functionality of apparatuses, etc. Once a
mode has been selected from the available operational modes defined
by, for example, a timing signal, an associated beacon period
indication and/or one or more associated diluted beacon period
indications (all of which may be transmitted in beacon frames), the
process may proceed to step 806 wherein the apparatus may
participate in the network in accordance with the selected
operational mode. In accordance with various embodiments of the
present invention, the apparatus may participate in the network
(e.g., contention) based on, for example, a multiple of the beacon
period that is defined by the beaconing mode. The operational mode
selected in apparatuses may also be known by other apparatuses, for
example, through messages that contain predefined information
elements (IEs) created for this purpose. Participation in the
network may continue in step 806 until the network is discontinued
in step 808. The process may then return to step 800 to await the
next requirement for link establishment.
[0049] If synchronization is not successful in step 812,
apparatuses that desire to join an existing network may continue to
attempt synchronization with the existing beacon in step 810 until
a threshold condition is met (as determined in step 816). Possible
threshold conditions may comprise, for example, a duration of time
without successful beacon synchronization (e.g., a timeout), a
number of unsuccessful synchronization attempts, etc. Once the
threshold condition has been determined to be met in step 816, the
process may proceed to step 818 wherein a decision is made that the
existing network is not available. The process may then return to
step 802 and follow the process flow pertaining to new network
creation (e.g., steps 802-808).
[0050] Further to the above, the various example embodiments of the
present invention are not strictly limited to the above
implementations, and thus, other configurations are possible.
[0051] For example, apparatuses in accordance with at least one
embodiment of the present invention may comprise means for
receiving a beacon frame comprising a timing signal, an associated
beacon period indication and an associated diluted beacon period
indication corresponding to a wireless network, means for
synchronizing a timing signal function to the received beacon
timing signal, and means for determining a mode of operation based
on the timing signal function, the beacon period indication and the
diluted beacon period indication.
[0052] Another example apparatus in accordance with at least one
embodiment of the present invention may comprise means for
initiating a wireless network, and means for transmitting one or
more beacon frames, the beacon frames including a timing signal, an
associated beacon period indication and an associated diluted
beacon period indication corresponding to the wireless network.
[0053] Accordingly, it will be apparent to persons skilled in the
relevant art that various changes in forma and detail can be made
therein without departing from the spirit and scope of the
invention. The breadth and scope of the present invention should
not be limited by any of the above-described exemplary embodiments,
but should be defined only in accordance with the following claims
and their equivalents.
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