U.S. patent number RE43,383 [Application Number 13/170,786] was granted by the patent office on 2012-05-15 for method for sharing hybrid resources in a wireless independent network, a station for the method, and a data format for the method and the station.
This patent grant is currently assigned to Samsung Electronics Co., Ltd.. Invention is credited to Kyung-hun Jang.
United States Patent |
RE43,383 |
Jang |
May 15, 2012 |
Method for sharing hybrid resources in a wireless independent
network, a station for the method, and a data format for the method
and the station
Abstract
In a system for sharing hybrid resources in an independent
network, each one of a plurality of stations preferably employs a
sharing authority transferring protocol that allows the network
control function to be moved from station to station depending on
the network traffic. Although a distributed coordination method is
normally used in the network, when an individual station determines
that a real-time data stream is intended for the station, an
apparatus having a method and data format for the use thereof
allows control to be transferred to the targeted station. This
allows the targeted station to control the sharing of the wireless
hybrid resources using a centralized control method in a direct
mode for the duration of the real-time service transmission,
thereby optimizing network efficiency. As a result of using the
distributed control authority of the present invention, a station
may be freely subscribe/withdraw to/from the network.
Inventors: |
Jang; Kyung-hun (Suwon,
KR) |
Assignee: |
Samsung Electronics Co., Ltd.
(Suwon-Si, KR)
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Family
ID: |
46033372 |
Appl.
No.: |
13/170,786 |
Filed: |
June 28, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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12718087 |
Mar 5, 2010 |
Re. 42850 |
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Reissue of: |
10314295 |
Dec 9, 2002 |
7453846 |
Nov 18, 2008 |
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Foreign Application Priority Data
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Dec 12, 2001 [KR] |
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2001-78664 |
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Current U.S.
Class: |
370/329; 455/509;
370/342; 370/450; 370/348; 370/445; 709/201; 709/223; 455/451;
455/452.1; 370/449 |
Current CPC
Class: |
H04W
72/10 (20130101); H04W 74/02 (20130101) |
Current International
Class: |
H04W
4/00 (20090101) |
Field of
Search: |
;370/329,328,445,449,450 |
References Cited
[Referenced By]
U.S. Patent Documents
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2003-143159 |
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Jan 2002 |
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Other References
European Search Report issued on Jul. 2, 2003, in counterpart
European Application No. 02255827.4 (3 pages, in English). cited by
other .
Korean Office Action issued on Dec. 10, 2003, in counterpart Korean
Application No. 10-2001-0078664 (4 pages, in Korean, including
complete English translation). cited by other .
Chinese Office Action issued on Jan. 2, 2004, in counterpart
Chinese Application No. 021419647 (Office Action summary only, 4
pages, in Chinese, including complete English translation). cited
by other .
Japanese Office Action issued on Jun. 15, 2005, in counterpart
Japanese Application No. 2002-360101 (2 pages, in Japanese, no
English translation). cited by other .
U.S. Appl. No. 12/718,087, filed Mar. 5, 2010, Kyung-hun Jang,
Samsung Electronics Co., Ltd. cited by other .
U.S. Appl. No. 13/171,092, filed Jun. 28, 2011, Kyung-hun Jang,
Samsung Electronics Co., Ltd. cited by other .
U.S. Appl. No. 13/171,255, filed Jun. 28, 2011, Kyung-hun Jang,
Samsung Electronics Co., Ltd. cited by other .
U.S. Appl. No. 13/171,369, filed Jun. 28, 2011, Kyung-hun Jang,
Samsung Electronics Co., Ltd. cited by other.
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Primary Examiner: Milord; Marceau
Attorney, Agent or Firm: NSIP Law
Parent Case Text
.Iadd.CROSS-REFERENCE TO RELATED APPLICATIONS.Iaddend.
.Iadd.Notice: More than one reissue application has been filed for
a reissue of U.S. Pat. No. 7,453,846. The reissue applications are
Reissue application Ser. No. 12/718,087, which is for a reissue of
U.S. Pat. No. 7,453,846, and Continuation Reissue application Ser.
Nos. 13/170,786 (the present continuation reissue application),
13/171,092, 13/171,255, and 13/171,369, all of which are
continuation reissue applications of Reissue application Ser. No.
12/718,087, and all of which are for a reissue of U.S. Pat. No.
7,453,846. This reissue application is a continuation reissue
application of Reissue application Ser. No. 12/718,087 filed on
Mar. 5, 2010, now U.S. Pat. No. Re. 42,850, which is for a reissue
of U.S. Pat. No. 7,453,846, which issued on Nov. 18, 2008, from
application Ser. No. 10/314,295 filed on Dec. 9, 2002, which claims
the benefit of Korean Application No. 2001-78664 filed on Dec. 12,
2001..Iaddend.
Claims
What is claimed is:
.[.1. A method for sharing wireless hybrid resources among stations
in a wireless independent network, the method comprising: (a)
determining whether currently transmitted data is related to a
real-time service when the sharing of the wireless hybrid resources
is controlled by a distributed coordination method; (b) requesting
and receiving a sharing control authority by the distributed
coordination method, and controlling the sharing of the wireless
hybrid resources by a centralized control method in a direct mode
until the real-time service ends if it is determined that the
currently transmitted data is related to the real-time service,
wherein the sharing control authority corresponds to an authority
which controls the sharing of the wireless hybrid resources..].
.[.2. The method as claimed in claim 1, further comprising (c)
controlling the sharing of the wireless hybrid resources by the
distributed coordination method if it is determined that the
currently transmitted data is not related to the real-time
service..].
.[.3. The method as claimed in claim 1, wherein (b) comprises: (b1)
requesting the sharing control authority by the distributed
coordination method if it is determined that the currently
transmitted data is related to the real-time service; (b2)
determining whether the request for the sharing control authority
is rejected; (b3) controlling the sharing of the wireless hybrid
resources with a request for periodic polling, if it is determined
that the request is rejected; (b4) determining whether the sharing
of the wireless hybrid resources does not need to be controlled
during the real-time service, going back to step (b1) if it is
determined that the sharing of the wireless hybrid resources does
not need to be controlled during the real-time service, and going
back to step (b3) if it is determined the sharing of the wireless
hybrid resources still needs to be controlled during the real-time
service; (b5) receiving the sharing control authority and
controlling the sharing of the wireless hybrid resources by the
centralized control method in the direct mode if it is determined
that the request for the sharing control system is not rejected;
(b6) determining whether the real-time service ends and going back
to step (b5) if it is determined that the real-time service does
not end; and (b7) returning the sharing control authority if it is
determined that the real-time service ends, wherein the sharing of
the wireless hybrid resources is controlled by the distributed
coordination method..].
.[.4. The method as claimed in claim 1, wherein: (a) further
comprises identifying a station subject to the real-time service as
a subject station; and (b) comprises requesting and receiving the
sharing control authority by the subject station in accordance with
the distributed coordination method, and controlling the sharing of
the wireless hybrid resources by the subject station in accordance
with the centralized control method in the direct mode until the
real-time service ends if it is determined that the currently
transmitted data is related to the real-time service..].
.[.5. The method as claimed in claim 4, wherein the subject station
receives the sharing control authority when no other station in the
wireless independent network has the sharing control
authority..].
.[.6. A station for performing the wireless hybrid resources
sharing using a method for sharing wireless hybrid resources among
stations in a wireless independent network, the station comprising:
a transmission data checking unit configured to check whether
currently transmitted data is related to a real-time service and to
generate a control signal in response to the check result; and a
first controller configured to request and receive a sharing
control authority by a distributed coordination method and to
control sharing of the wireless hybrid resources by a centralized
control method in the direct mode until the real-time service ends,
in response to the control signal..].
.[.7. The station as claimed in claim 6, further comprising a
second controller which controls the sharing of the wireless hybrid
resources by the distributed coordination method in response to the
control signal..].
.[.8. The station as claimed in claim 6, wherein the first
controller comprises: a request message broadcaster, which
broadcasts a control authority requesting message requesting the
sharing control authority by the distributed coordination method in
response to the control signal and an enable signal; a request
rejecting message receiver, which receives a control authority
request rejecting message rejecting the request for the sharing
control authority and outputs a disable signal in response to the
received result; a polling requesting unit, which requests periodic
polling in response to the disable signal and the enable signal; a
releasing message receiver, which receives a control authority
releasing message in response to the control signal and outputs the
enable signal in response to the received result; a shared resource
controller, which receives the sharing control authority in
response to the disable signal and controls the sharing of the
wireless hybrid resources by the centralized control method in the
direct mode and transmits the sharing control authority releasing
message to another station and returns the sharing control
authority in response to an ending signal; and a service checking
unit, which checks whether the real-time service ends and outputs
the checked result as the ending signal, wherein a second
controller controls the sharing of the wireless hybrid resources by
the distributed coordination method in response to the ending
signal..].
.[.9. The data format as claimed in claim 8, wherein after the
request message broadcaster broadcasts the sharing control
authority requesting message, the shared resource controller is
idle for a PIFS and then receives the sharing control
authority..].
.[.10. The data format as claimed in claim 8, wherein the request
rejecting message receiver receives the message rejecting the
request for the sharing control authority when a SIFS elapses after
the request message broadcaster broadcasts the sharing control
authority requesting message..].
.[.11. The station as claimed in claim 6, wherein the first
controller controls the sharing of the wireless hybrid resources
when no other station among the stations has the sharing control
authority..].
.[.12. A controller for generating a data format for use in a
station for performing wireless hybrid resources sharing using a
method for sharing wireless hybrid resources among stations in a
wireless independent network, the controller generated data format
comprising: a control authority requesting message, which requests
sharing control authority by a distributed coordination method; a
control authority releasing message, which releases the sharing
control authority; and a plurality of transmission frames, which
are spaced apart from the control authority requesting message and
the control authority releasing message, respectively, by a PIFS,
are also spaced apart from each other by one PIFS, and have
variable lengths, respectively..].
.[.13. The data format as claimed in claim 12, wherein each of the
transmission frames comprises: a downlink section in which
real-time service-related data is transmitted to another station
and which has a variable length; a polling section in which the
other station related to the real-time service is polled and which
has a variable length; and a distribution control section in which
non-real-time service-related data is transmitted to another
station and which has a variable length..].
.[.14. The data format as claimed in claim 13, wherein the downlink
section is spaced apart from the polling section by a PIFS..].
.[.15. The data format as claimed in claim 13, wherein the polling
section is spaced apart from the distribution control section by a
DIFS..].
.[.16. The data format as claimed in claim 13, wherein the downlink
section comprises a plurality of packets which are spaced apart
from each other by a PIFS..].
.Iadd.17. A method for sharing wireless resources among stations in
a wireless network, the method comprising: determining whether
currently transmitted data satisfies a predetermined condition;
assuming sharing control authority to control the sharing of the
wireless resources if a result of the determining is that the
currently transmitted data satisfies the predetermined condition;
and controlling transmission of data by a station having the
sharing control authority after the assuming of the sharing control
authority..Iaddend.
.Iadd.18. The method of claim 17, wherein the controlling further
comprises controlling the transmission of data by the station by a
centralized control method; and the method further comprises
controlling transmission of data by a method other than the
centralized control method if a result of the determining is that
the currently transmitted data does not satisfy the predetermined
condition..Iaddend.
.Iadd.19. The method of claim 17, further comprising releasing the
sharing control authority after the controlling of the transmission
of the data..Iaddend.
.Iadd.20. The method of claim 17, wherein the predetermined
condition is whether the currently transmitted data is related to a
predetermined data type..Iaddend.
.Iadd.21. A station for performing a method for sharing wireless
resources among stations in a wireless network, the station
comprising: a transmission data checking unit to determine whether
currently transmitted data satisfies a predetermined condition; and
a first controller to: assume sharing control authority to control
the sharing of the wireless resources if the transmission data
checking unit determines that the currently transmitted data
satisfies the predetermined condition; and control transmission of
data by the station having the sharing control authority after the
first controller has assumed the sharing control
authority..Iaddend.
.Iadd.22. The station of claim 21, wherein the first controller
controls the transmission of data by the station by a centralized
control method; and the station further comprises a second
controller to control transmission of data by a method other than
the centralized control method if the transmission data checking
unit determines that the currently transmitted data does not
satisfy the predetermined condition..Iaddend.
.Iadd.23. The station of claim 21, wherein the first controller
releases the sharing control authority after the first controller
has controlled the transmission of the data..Iaddend.
.Iadd.24. The station of claim 21, wherein the predetermined
condition is whether the currently transmitted data is related to a
predetermined data type..Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wireless independent network
based on carrier sense multiplexing access (CSMA)/collision
avoidance (CA). More particularly, the present invention relates to
a method for sharing hybrid resources in a wireless independent
network, a station for the method, and a data format for the method
and the station.
2. Description of the Related Art
Wireless independent networks connect wireless stations without the
use of wires in a predetermined area regardless of connections to
base networks. For example, home networks connecting information
regarding home electronics without the use of wires is a type of
wireless independent network. Services in a wireless independent
network may generally be classified into a real-time AudioVideo
(AV) streaming service or a non-real-time AV streaming service.
An environment of such a wireless independent network may be
characterized as follows. First, since network subscribers'
interests concentrate on a real-time AV streaming service in one
independent network, it is rare for a large number of real-time AV
services to coexist in one independent network. Second, a small
number of real-time AV streaming services and a large number of
non-real-time AV streaming services can coexist in one independent
network. Third, the real-time AV streaming service uses a station
that is the subject thereof and limited holding time exists in the
service.
In the above-described wireless independent network environment,
wireless stations (STAs) typically share wireless communications
resources. Here, a conventional resource-sharing method may
generally be classified into a distributed coordination method or a
centralized control method.
The distributed coordination method uses a mechanism for minimizing
possible message collisions that occur when stations attempt to use
a data channel simultaneously. This mechanism is the IEEE 802.11a
distributed coordination function (DCF) based on CSMA/CA. In a
distributed coordination method using a DCF, random backoff numbers
are created to minimize competition-based collisions, the backoff
numbers are reduced by stages when a channel is idle for at least a
predetermined period of time (in the case of IEEE 802.11, this is
referred to as DCF Interframe Space (DIFS)), and data is
transmitted when the backoff number becomes "0". A conventional
distributed coordination method for grading priorities of the
occupation of resources according to a specific type of data
includes a Point Coordination Function (PCF) Interframe Space
(PIFS) system and a Short lnterframe Space (SIFS). Priorities of
these systems are in the relationship DIFS>PIFS>SIFS, and a
station using SIFS has priority over a station using DIFS. However,
since a DCF system works on a probabilistic base, it is still
possible for stations to collide.
In the centralized control method, one control station controls
resources shared in a wireless independent network in a bundle.
Thus, wireless stations share wireless resources according to the
instructions of the control station. The centralized control method
may be subdivided into a direct mode and an indirect mode. In the
direct mode, a control station controls the time slots for
transmission and reception among wireless stations so that the
wireless stations directly communicate with one another. The
HiperLAN/2 standard is a representative example of the direct mode.
In the indirect mode, transmission data of all stations is
transmitted to the control station so that the wireless stations
indirectly communicate with one another through the control
station. This indirect mode is based on the Bluetooth standard.
Accordingly, in the above-described distributed coordination
method, a specific control station is not required, and a mesh
network can be constituted, and a station may easily subscribe to
and withdraw from the mesh network. However, the distributed
coordination method uses resources ineffectively and cannot support
the real-time AV streaming service. In addition, the centralized
control method in the indirect mode cannot support the real-time AV
streaming service due to the forwarding of packets, which
concentrates loading on the control station, and requires the
selection of a substitute node when the control station withdraws
from the subscribed network. Although the centralized control
method in the direct mode uses resources effectively, supports the
real-time AV streaming service, and constitutes the mesh network,
loading is concentrated on the control station, thus requiring the
selection of a substitute node when the control station withdraws
from the subscribed network.
The aforementioned conventional resource-sharing methods have many
problems since they have been developed based on non-real-time
services, or due to inflexible structure of networks.
SUMMARY OF THE INVENTION
In an effort to solve the above-described problems, it is a first
feature of an embodiment of the present invention to provide a
method for sharing hybrid resources in a wireless independent
network that can have the advantages of conventional
resource-sharing methods by more efficiently analyzing the
environment of the wireless independent network so that wireless
resources are shared adaptive to the environment, thereby
efficiently supporting real-time services as well as non-real-time
services among the wireless stations.
It is a second feature of an embodiment of the present invention to
provide stations performing the hybrid resources sharing
method.
It is a third feature of an embodiment of the present invention to
provide formats of data transmitted among the stations.
Accordingly, a method for sharing wireless hybrid resources among
stations in a wireless independent network preferably includes
analyzing a received data stream and obtaining network control for
optimally transferring that data. An analysis is performed to
determine whether currently transmitted data is related to a
real-time service when the sharing of the wireless hybrid resources
is controlled by a distributed coordination method. A sharing
control authority is requested and received by the distributed
coordination method, and the sharing of the wireless hybrid
resources is controlled by a centralized control method in a direct
mode until the real-time service ends if it is determined that the
currently transmitted data is related to the real-time service. The
sharing control authority corresponds to an authority which
controls the sharing of the wireless hybrid resources. If it is
determined that the currently transmitted data is not related to
the real-time service, the sharing of the wireless hybrid resources
may be controlled by the distributed coordination method.
Obtaining network control when the currently transmitted data is
related to the real-time service preferably includes requesting the
sharing control authority by the distributed coordination method if
it is determined that the currently transmitted data is related to
the real-time service; determining whether the request for the
sharing control authority is rejected; controlling the sharing of
the wireless hybrid resources with a request for periodic polling,
if it is determined that the request is rejected; and then
determining whether the sharing of the wireless hybrid resources
does not need to be controlled during the real-time service. If it
is determined that the sharing of the wireless hybrid resources
does not need to be controlled during the real-time service,
control is transferred to the aforementioned requesting step. If it
is determined the sharing of the wireless hybrid resources still
needs to be controlled during the real-time service, control is
returned to the step for requesting for periodic polling.
If it is determined that the request for the sharing control
authority is not rejected, the method preferably additionally
includes receiving the sharing control authority and controlling
the sharing of the wireless hybrid resources by the centralized
control method in the direct mode; determining whether the
real-time service ends and returning to the receiving step if it is
determined that the real-time service does not end; and returning
the sharing control authority if it is determined that the
real-time service ends. In the foregoing additional steps, the
sharing of the wireless hybrid resources is preferably controlled
by the distributed coordination method.
A preferred embodiment of a station for performing the wireless
hybrid resources sharing method according to the present invention
preferably includes a transmission data checking unit and a first
controller. The preferred embodiment of the station may further
include a second controller. The transmission data checking unit
checks whether the currently transmitted data is related to the
real-time service and generates a control signal in response to the
check result. In response to the control signal, the first
controller requests and receives the sharing control authority by
the distributed coordination method and controls the sharing of the
wireless hybrid resources by the centralized control method in the
direct mode until the real-time service ends. Alternately, a second
controller may control the sharing of the wireless hybrid resources
by the distributed coordination method in response to the control
signal.
The first controller preferably further includes a request message
broadcaster, which broadcasts a control authority requesting
message requesting the sharing control authority by the distributed
coordination method in response to the control signal and an enable
signal; a request rejecting message receiver, which receives a
control authority request rejecting message rejecting the request
for the sharing control authority and outputs a disable signal in
response to the received result; a polling requesting unit, which
requests periodic polling in response to the disable signal and the
enable signal; a releasing message receiver, which receives a
control authority releasing message in response to the control
signal and outputs the enable signal in response to the received
result; a shared resource controller, which receives the sharing
control authority in response to the disable signal and controls
the sharing of the wireless hybrid resources by the centralized
control method in the direct mode and transmits the sharing control
authority releasing message to another station and returns the
sharing control authority in response to an ending signal; and a
service checking unit, which checks whether the real-time service
ends and outputs the checked result as the ending signal.
Preferably, a second controller controls the sharing of the
wireless hybrid resources by the distributed coordination method in
response to the ending signal.
To operate the foregoing preferred station using the foregoing
preferred method for sharing wireless hybrid resources, a data
format preferably includes a control authority requesting message,
a control Authority releasing message, and a plurality of
transmission frames located therebetween. The control authority
requesting message requests the sharing control authority by the
distributed coordination method. The control authority releasing
message releases the sharing control authority. The plurality of
transmission frames are spaced apart from the control authority
requesting message and the control authority releasing message, by
a PIFS, are also spaced apart from each other by one PIFS, and may
have variable lengths.
Each one of the plurality of transmission frames preferably further
includes a downlink section in which the real-time service-related
data is transmitted to another station and which may have a
variable length; a polling section in which the other stations
related to the real-time service is polled and which has a variable
length; and a distribution control section in which non-real-time
service-related data is transmitted to another station and which
may have a variable length. The downlink section is preferably
spaced apart from the polling section by a PIFS. The polling
section is preferably spaced apart from the distribution control
section by a DIFS. The downlink section preferably includes a
plurality of packets which are spaced apart from each other by a
PIFS.
In the event that a share request rejection message is received in
the station, a sharing control authority message may also be
received. In such a case, the shared resource controller is
preferably idle for a PIFS period, thereby necessitating the
inclusion of a PIFS time period between the time of the request for
sharing control authority and the receipt of the sharing control
authority. Additionally, in the event a sharing rejection message
is transmitted by the sharing controller, preferably a SIFS time
period is included in the format between the time of transmission
of the request and the time of receipt of the rejection
message.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features and advantages of the present
invention will become readily apparent to those of ordinary skill
in the art by describing in detail preferred embodiments thereof
with reference to the attached drawings in which:
FIG. 1 illustrates a flowchart of a method for sharing hybrid
resources in a wireless independent network according to the
present invention;
FIG. 2 illustrates a flowchart of a preferred embodiment of step 12
shown in FIG. 1 according to the present invention;
FIG. 3 illustrates a block diagram of a station, according to the
present invention, performing the hybrid resources sharing method
shown in FIG. 1;
FIG. 4 illustrates a block diagram of a preferred embodiment of a
first controller shown in FIG. 3 according to the present
invention;
FIGS. 5(a), (b), and (c) illustrate data formats for the
above-described hybrid resources sharing method and the station
according to the present invention;
FIG. 6 illustrates an exploded view of a preferred embodiment of a
downlink section shown in FIG. 5(c); and
FIGS. 7(a) and (b) illustrate how the sharing control authority is
obtained and how a message rejecting the request for the sharing
control authority is received from a control station, respectively,
after a message requesting a sharing control authority is
broadcasted.
DETAILED DESCRIPTION OF THE INVENTION
Korean Patent Application No. 2001-78664, filed Dec. 12, 2001, and
entitled: "Method for Sharing Hybrid Resources in Wireless
Independent Network, Station for the Method, and Data Format for
the Method and the Station," is incorporated by reference herein in
its entirety.
Hereinafter, a method for sharing hybrid resources in a wireless
independent network according to the present invention will be
described with reference to the attached drawings. In the drawings,
like reference numerals refer to like elements throughout.
FIG. 1 illustrates a flowchart of a preferred method for sharing
hybrid resources in a wireless independent network according to the
present invention. Selection of either a centralized control method
in a direct mode or a distributed coordination method is preferably
dependent on whether real-time service-related data is transmitted.
In step 10, a determination is made as to whether currently
transmitted data is related to a real-time service when the sharing
of the wireless resources is controlled based on the
above-described distributed coordination method. For example, it
may be determined that a real-time AV streaming service is being
generated, i.e., the real-time AV streaming service is provided via
a wireless independent network. If the currently transmitted data
is not related to the real-time service, the distributed
coordination method is retained in step 14.
If, however, the currently transmitted data is related to the
real-time service when the sharing of the wireless resources is
controlled by the distributed coordination method, in step 12, a
station which is the subject of the real-time service (hereinafter
referred to as "subject station") requests a sharing control
authority using the distributed coordination method. After the
request is admitted sharing control authority is granted to the
subject station, and wireless resources are shared under control of
the subject station preferably using the centralized control method
in a direct mode for the duration of the transmission of the
corresponding real-time service. At the completion of the real-time
service transmission the subject station restores the sharing of
the wireless resources to the distributed coordination method.
FIG. 2 illustrates a flowchart of a preferred embodiment of step 12
shown in FIG. 1 according to the present invention. Step 12
preferably includes steps 20 and 22 for requesting the sharing
control authority, steps 24 through 28 for controlling the sharing
of wireless resources with a request for periodic polling when the
requested sharing control authority is rejected, and steps 30
through 34 for controlling the sharing of the wireless resources by
the centralized control method in the direct mode until the
real-time service ends when the requested sharing control authority
is admitted.
After it is determined that the currently transmitted data is
related to the real-time service, in step 20 the subject station
requests the sharing control authority using the distributed
coordination method, e.g., a DCF system. In step 22, the subject
station determines whether the request for sharing control
authority has been rejected. In other words, the subject station
determines whether a station currently having a sharing control
authority (hereinafter referred to as a "control station") exists
by testing for the existence of a "rejection message" from that
control station.
If it is determined that the request for the sharing control
authority is rejected, in step 24 the sharing of the wireless
resources is controlled while the subject station requests the
control station for periodic polling. For example, if the control
station exists, the subject station cannot be granted the sharing
control authority, and the control station maintains the sharing
control of the wireless resources and a corresponding real-time AV
streaming service-related communication is implemented using the
existing method.
In step 26 the subject station determines whether the real-time
service is still being transmitted, i.e., still in progress. If it
is determined that the real-time service is still being
transmitted, in step 28 the subject station determines whether the
sharing of the wireless resources needs to be controlled. In other
words, if it has been determined that the real-time service is in
process, the subject station monitors whether a control authority
releasing message has been received from the control station.
If it is determined through the periodic polling that the sharing
of the wireless resources does not need to be controlled by the
control station for performing the corresponding real-time
service-related communication, the process returns to step 20. In
other words, when the subject station does not need to be
controlled by the control station any more, it requests the
acquisition of the sharing control authority by the distributed
coordination method again. However, if it is determined that the
subject stations still needs to be controlled by the control
station to share the wireless resources when the real-time service
is in progress, the process returns to step 24.
Alternatively, if it is determined that the request for the sharing
control authority has not been rejected, in step 30 the subject
station is granted (i.e., assumes or seizes) the sharing control
authority and preferably controls the sharing of the wireless
resources by the centralized control method in the direct mode. In
step 32, it is determined whether the real-time service has ended.
If it is determined that the real-time service has not ended, the
process repeats step 30, such that the subject station retains the
sharing control authority. However, if it is determined that the
real-time service has ended, in step 34 the subject station
broadcasts a new control authority releasing message to the other
stations to return the sharing control authority to the network.
When it is determined that the real-time service is not in progress
in step 26 or after step 34, the subject station changes the
sharing controls back to the distributed coordination method.
A preferred embodiment according to the present invention, showing
the structure and operation of stations in an independent network
performing the previously described hybrid resources sharing method
will be described with reference to FIGS. 3 and 4.
FIG. 3 illustrates a block diagram of a station for performing the
hybrid resources sharing method shown in FIG. 1, according to an
embodiment of the present invention. The station preferably
includes a transmission data checking unit 50, and a first and a
second controller 52 and 54, respectively. For a better
understanding of the present invention, the structure and operation
of the station shown in FIG. 3 will be described assuming that the
station is a subject station.
The transmission data checking unit 50 checks whether currently
transmitted data input via an input port IN1 is related to a
real-time service and outputs a control signal to first and second
controllers 52 and 54, respectively. First and second controllers
52 and 54 generate output control and data signals in response to
the check result.
If first controller 52 is granted a sharing control authority in
response to the control signal input from the transmission data
checking unit 50, the sharing of wireless resources .[.on a central
controls system in a direct mode.]. is controlled by first
controller 52 .Iadd.using a centralized control method in a direct
mode .Iaddend.until the real-time service ends. To perform this
control function, if it is perceived through the control signal
that data input via the input port IN1 is transmission data for the
real-time service, the first controller 52 outputs a signal
requesting the sharing control authority to the other stations via
an output port OUT1 and checks whether a message rejecting the
request for the sharing control authority is received from another
station, e.g., a control station (not shown), via the input port
IN1. If the first controller 52 is granted the sharing control
authority (i.e., not rejected) data input through the input port
IN1 via the transmission data checking unit 50 is transmitted to a
corresponding station (not shown) via the output port OUT1.
The second controller 54 controls the sharing of the wireless
resources by the distributed coordination method in response to the
control signal input from the transmission data checking unit 50.
Here, the second controller 54 preferably receives data from
another station via an input port IN3 and outputs the data input
through the input port IN1 via the transmission data checking unit
50 to another station via an output port OUT2. Here, the second
controller 54 may control the sharing of the wireless resources by
the distributed coordination method in response to an ending signal
generated when the real-time services ends in the first controller
52.
FIG. 4 illustrates a block diagram of a preferred embodiment of the
first controller 52 shown in FIG. 3. The first controller 52
preferably includes a request message broadcaster 70, a request
rejecting message receiver 72, a polling requesting unit 74, a
releasing message receiver 76, a shared resource controller 78, and
a service checking unit 80.
To perform step 20, in response to the control signal from
transmission data checking unit 50 via an input port IN4
(indicating that received data is related to a real-time
.[.service,).]. .Iadd.service), .Iaddend.the request message
broadcaster 70 transmits a message requesting control authority to
the other stations via an output port OUT3 using the distributed
coordination method. The request message is additionally gated
using an enable signal input from the releasing message receiver
76. If one of the other stations has sharing control authority
(i.e., is processing data), that "control station" transmits a
rejection message to the subject station. When the control station
has completed its data processing activity, it transmits a sharing
control authority releasing message using the distributed
coordination method. If, however, there is no .[.current.].
.Iadd.active .Iaddend.control station, no rejection message will be
received.
To perform step 22, the request rejecting message receiver 72
receives any message rejecting the request for the sharing control
authority via an input port IN5 and outputs the received message as
a disable signal to the polling requesting unit 74 and the shared
resource controller 78. In response to the disable signal from the
request rejecting message receiver 72 and the enable signal input
from the releasing message receiver 76, the polling requesting unit
74, which performs step 24, requests the periodic polling from the
control station via an output port OUT4. In other words, the
polling requesting unit 74 requests the periodic polling of the
control station whenever a rejection message is received and the
sharing control authority releasing message has not yet been
received.
To perform steps 26 and 28, in response to the control signal input
from the transmission data checking unit 50 via the input port IN4
(indicating the real-time service) the releasing message receiver
76 monitors the control station for the sharing control authority
releasing message via an input port IN6. When the sharing control
authority releasing message is received, releasing message receiver
76 outputs an enable signal to the request message broadcaster 70
and the polling requesting unit 74. The releasing message receiver
76 may generate an enable signal having a first logic level if the
sharing control authority releasing message is received from the
control station and an enable signal having a second logic level if
the control authority releasing message is not received from the
control station.
For the case where no rejection message is received, the shared
resource controller 78, which performs steps 30 and 34, assumes the
sharing control authority in response to the disable signal input
from the request rejecting message receiver 72 and thus controls
the sharing of the wireless resources using the centralized control
method in the direct mode. Here, the shared resource controller 78
may receive data from another station via an input port IN7 or may
output data for the real-time service to another station via an
output port OUT5. Also, in step 34, the shared resource controller
78 preferably transmits the sharing control authority releasing
message to another station via the output port OUT5 to return the
sharing control authority in response to the ending signal input
from the service checking unit .[.and sharing control authority.].
80. Although it is not shown as a step in FIG. 2, during the time
that the subject station has the control authority, the shared
resource controller 78 preferably transmits the sharing control
rejection messages upon being queried by other stations.
The service checking unit 80, which performs step 32, checks
whether the real-time service has ended and outputs the check
result as the ending signal to the shared resource controller 78
and to the second controller 54 via the output port OUT6. Here, the
second controller 54 controls the sharing of the wireless resources
by the distributed coordination method in response to the ending
signal input from the service checking unit 80.
Hereinafter, a data format for the hybrid resource-sharing method
and the station according to the present invention will be
described with reference to the attached drawings.
FIGS. 5(a), (b), and (c) illustrate a timing diagram of a streaming
messaging signal having a plurality of partitioning sections
according to a preferred data format for the above-described
resource-sharing method and station according to the present
invention. FIG. 5(a) shows sections of the complete data stream and
FIGS. 5(b) and 5(c) show exploded views of the partitions of a
transmission frame.
According to the present invention, step 10 of the preferred method
shown in FIG. 1 is performed .[.by.]. .Iadd.during .Iaddend.a
distributed coordination method .[.during.]. section 90 shown in
FIG. 5(a). Here, if it is determined that currently transmitted
data is related to the real-time service, step 12 is performed
during an adaptive control method section 92 shown in FIG. 5(a).
For this, the subject station obtains the sharing control authority
at a starting point 97 of the adaptive control .[.system.].
.Iadd.method .Iaddend.section 92. The length 96 of the adaptive
control .[.system.]. .Iadd.method .Iaddend.section 92 may vary.
When the real-time service ends during step 12, the subject station
returns the sharing control authority at an ending point 98 of the
adaptive control .[.system.]. .Iadd.method .Iaddend.section 92.
As shown in FIG. 5(b), the adaptive control .[.system.].
.Iadd.method .Iaddend.section 92 shown in FIG. 5(a) preferably
includes a control authority requesting message 100, a series of
first through n-th transmission frames 102, 104, . . . and 106, and
a control authority releasing message 108. The first transmission
frame 102 is spaced apart from the control authority requesting
message 100 by a Point Coordination Function (PCF) Interframe Space
(PIFS) 120 and the n-th transmission frame 106 is spaced apart from
the control authority releasing message 108 by a PIFS 126. The
first through n-th transmission frames 102, 104, . . . , and 106
are spaced apart from each other by a PIFS 122 to have priority of
the occupation of the resources over DCF-based wireless stations.
Here, the first through n-th transmission frames 102, 104, . . .
and 106 have lengths 124, respectively, which may vary depending on
characteristics of a corresponding AV streaming service.
As shown in FIG. 5(c), each one of the first through n-th
transmission frames 102, 104, . . . and 106 preferably includes a
downlink section 140, a polling section 142, and a distribution
control section 144. In the downlink section 140, real-time
service-related transmission data is transmitted to another station
and the downlink section 140 has a variable length 160. In the
polling section 142, which has a variable length 162, other
real-time service-related stations may be polled, and a multiplex
polling system may be used for improved performance. In the polling
section 142, a packet is forwarded from the subject station to the
control station or another station.
In the distribution control section 144, which has a variable
length 164, non-real-time service-related transmission data is
preferably transmitted to another station using a DCF system. If an
additional real-time AV streaming service is generated, the message
requesting the periodic polling may be transmitted to the control
station. Here, the downlink section 140 is spaced apart from the
polling section 142 by a PIFS 170, and the polling section 142 is
spaced apart from the distribution control section 144 by a DIFS
172.
FIG. 6 illustrates an exploded view of a preferred embodiment of
the downlink section 140 of FIG. 5(c) according to the present
invention, which preferably includes a plurality of packets 182,
184, . . . and 186. Referring to FIG. 6, the plurality of packets
182, 184, . . . and 186 are spaced apart from each other by a PIFS
180 to maintain the sharing control authority for the downlink
section 140.
FIGS. 7(a) and (b) illustrate views explaining how the sharing
control authority is obtained and how the message rejecting the
request for the sharing control authority is received from the
control station, respectively, after the message requesting the
sharing control authority has been transmitted. In FIG. 7(a), there
is no .[.current.]. .Iadd.active .Iaddend.control station, while in
FIG. 7(b), there is .[.a current.]. .Iadd.an active
.Iaddend.control station.
As shown in FIG. 7(a), the request message broadcaster 70 transmits
a control authority requesting message 192 via the output port
OUT3. After the shared resource controller 78 shown in FIG. 4 is
idle for a PIFS 190, sharing control authority is assumed in
section 194.
For the case where an active control station exists, as shown in
FIG. 7(b), the request message broadcaster 70 broadcasts a control
authority requesting message 202. Then after a SIFS 200 elapses,
the request rejecting message receiver 72 shown in FIG. 4 receives
a control authority request rejecting message 204 from the active
control station. After a variable time duration 206 during which
the active control station completes its control task, a sharing
control authority releasing message 208 is transmitted by the
active control station, thereby releasing network sharing control
authority.
At this time the request message broadcaster 70 again transmits a
control authority requesting message 192 as in FIG. 7(a), and after
the shared resource controller 78 is idle for a PIFS 190, sharing
control authority is assumed in section 194. In an alternate
embodiment, the active control station may transmit the sharing
control authority releasing message 208 directly to the requesting
station, thereby allowing the requesting station to immediately
assume sharing control authority in section 194, and thus avoiding
the loss of time periods 190 and 192.
As described above, in a preferred method for sharing hybrid
resources in a wireless independent network, a station for the
method, and a data format for the method and the station,
non-real-time service-related data packets are transmitted/received
using a distributed coordination method and real-time
service-related data packets are transmitted/received using a
centralized control method in a direct mode. In other words, hybrid
data is transmitted and received in a wireless independent network.
Thus, an efficiency of using resources is maximized, a real-time
service of the resources is supported, and a mesh network may be
constituted. Further, loading may be prevented from concentrating
in a control station and the control station is not fixed. As a
result, a station can freely subscribe/withdraw to/from a
subscribed network.
Preferred embodiments of the present invention have been disclosed
herein and, although specific terms are employed, they are used and
are to be interpreted in a generic and descriptive sense only and
not for purpose of limitation. Accordingly, it will be understood
by those of ordinary skill in the art that various changes in form
and details may be made without departing from the spirit and scope
of the present invention as set forth in the following claims.
* * * * *