WO2007029973A1 - Method for transmitting and receiving beacon information in wireless lan mesh network - Google Patents

Method for transmitting and receiving beacon information in wireless lan mesh network Download PDF

Info

Publication number
WO2007029973A1
WO2007029973A1 PCT/KR2006/003559 KR2006003559W WO2007029973A1 WO 2007029973 A1 WO2007029973 A1 WO 2007029973A1 KR 2006003559 W KR2006003559 W KR 2006003559W WO 2007029973 A1 WO2007029973 A1 WO 2007029973A1
Authority
WO
WIPO (PCT)
Prior art keywords
offset
timing information
beacon timing
beacon
method
Prior art date
Application number
PCT/KR2006/003559
Other languages
French (fr)
Inventor
Jae-Hoon Kim
Ji-Hoon Lee
Young-Gon Choi
Jung-Ho Kim
Original Assignee
Samsung Electronics Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to US71427105P priority Critical
Priority to US60/714,271 priority
Priority to KR10-2006-0064929 priority
Priority to KR1020060064929A priority patent/KR101269853B1/en
Application filed by Samsung Electronics Co., Ltd. filed Critical Samsung Electronics Co., Ltd.
Publication of WO2007029973A1 publication Critical patent/WO2007029973A1/en

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W56/00Synchronisation arrangements
    • H04W56/0055Synchronisation arrangements determining timing error of reception due to propagation delay
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W8/00Network data management
    • H04W8/005Discovery of network devices, e.g. terminals
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W84/00Network topologies
    • H04W84/18Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

Provided is a method for transmitting beacon timing information from a transmission node in a wireless Local Area Network (LAN) mesh network. In the method, each of a plurality of nodes transmits a beacon signal with its unique offset within a beacon signal transmission time period and the transmission node periodically transmits beacon timing information including a first unique offset within the beacon signal transmission time period. The transmission node sets a second offset different from the first offset and transmits probe beacon timing information including the first offset and the second offset.

Description

METHOD FOR TRANSMITTING AND RECEIVING BEACON INFORMATION IN WIRELESS LAN MESH NETWORK

BACKGROUND OF THE INVENTION

Field of the Invention:

The present invention generally relates to a mesh network. More particularly, the present invention relates to a method for transmitting information associated with a beacon signal in a wireless mesh network.

Description of the Related Art:

In a mobile communication system, a Mesh Point (MP) has a limited range in which a signal can be wirelessly transmitted. To solve this problem, a multi hop technique is used for communication with another MP or an Access Point (AP) that is outside the wireless transmission range of the MP. An example of a communication system using the multi hop technique is a wireless mesh network. A wireless mesh network is a communication system in which each MP performs data communication and relays and routes a signal received from another MP in the same network to yet another MP.

To prevent signal collision between MPs in the wireless mesh network, synchronization is employed. To facilitate synchronization, a beacon signal is used. Each of the MPs transmits the beacon signal with a predetermined time offset. Thus, beacon signal detection is essential for smooth communication between the MPs. However, a beacon signal of an MP may collide with a beacon signal of another MP due to the occurrence of a special event. Thus, if beacon signals collide with each other or a collision between the beacon signals is not previously detected, a network may segregate and a specific MP may fail to join the network. Accordingly, there is a need for preventing collisions between beacon signals in a wireless mesh network.

SUMMARY OF THE INVENTION

Exemplary embodiments of the present invention address at least the above problems and/or disadvantages and provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a method for preventing collisions between beacon signals in a wireless mesh network by transmitting a beacon signal from each MP at a different time.

According to one aspect of an exemplary embodiment of the present invention, there is provided a method for transmitting beacon timing information from a transmission node in a wireless Local Area Network (LAN) mesh network. In the method, each of a plurality of nodes transmits a beacon signal with its unique offset within a beacon signal transmission time period and the transmission node periodically transmits beacon timing information comprising a first unique offset within the beacon signal transmission time period. The transmission node sets a second offset different from the first offset and transmits probe beacon timing information including the first offset and the second offset.

According to another aspect of an exemplary embodiment of the present invention, there is provided a method for receiving beacon timing information at a reception node in a wireless Local Area Network (LAN) mesh network. The method includes the steps of receiving the beacon timing information from a transmission node, detecting whether the received beacon timing information includes the Medium Access Control (MAC) address of the transmission node, detecting a first offset and a second offset that are the beacon timing information of the transmission node if the received beacon timing information includes the Medium Access Control (MAC) address of the transmission node, checking if the second offset is the same as offsets of other transmission nodes, and selecting the first offset to transmit a beacon timing information retransmission request if the second offset is the same as offsets of other transmission nodes.

According to yet another aspect of an exemplary embodiment of the present invention, there is provided a computer-readable recording medium storing a program for implementing a method for transmitting beacon timing information from a transmission node in a wireless Local Area Network (LAN) mesh network. In the method, each of a plurality of nodes transmits a beacon signal with its unique offset within a beacon signal transmission time period and the transmission node periodically transmits beacon timing information including a first offset as its unique offset within the beacon signal transmission time period. The transmission node sets a second offset that is different from the first offset and transmits probe beacon timing information including the first offset and the second offset.

According to still another aspect of an exemplary embodiment of the present invention, there is provided a computer-readable recording medium storing a program for implementing a method for receiving beacon timing information at a reception node in a wireless Local Area Network (LAN) mesh network. The method includes the steps of receiving the beacon timing information from a transmission node, detecting whether the received beacon timing information includes the Medium Access Control (MAC) address of the transmission node, detecting a first offset and a second offset that are the beacon timing information of the transmission node if the received beacon timing information includes the Medium Access Control (MAC) address of the transmission node, checking if the second offset is the same as offsets of other transmission nodes, and selecting the first offset to transmit a beacon timing information retransmission request if the second offset is the same as offsets of other transmission nodes.

Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of certain embodiments of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIGs. IA and IB illustrate examples of collision between beacon signals; FIG. 2 illustrates the format of a probe beacon timing element according to an exemplary embodiment of the present invention;

FIG. 3 illustrates the format of a probe response beacon timing element according to an exemplary embodiment of the present invention; and FIG. 4 is a flowchart illustrating a process in which a reception MP processes a beacon signal according to an exemplary embodiment of the present invention.

Throughout the drawings, the same drawing reference numerals will be understood to refer to the same elements, features, and structures.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The matters defined in the description such as a detailed construction and elements are provided to assist in a comprehensive understanding of the embodiments of the invention and are merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

Exemplary embodiments of the present invention include a method for transmitting and receiving beacon information to detect and avoid collisions between beacon signals in a wireless mesh network. In particular, a Mesh Access Point (MAP) or a Mesh Point (MP) transmits a beacon signal at a different time than a beacon signal of another recognized MP or MAP. By transmitting beacon signals at a different times, collisions between the beacon signals is prevented. In an exemplary implementation, the MAP and the MP are fixed or mobile nodes. The MAP manages a client node and the MP performs signal forwarding without a client node.

Prior to the explanation of exemplary embodiments of the present invention, the occurrence of collisions between beacon signals will be described in greater detail. A collision may occur as shown in FIGs. IA and IB.

Generally, each of a plurality of MPs transmits a beacon signal within a certain beacon signal transmission time period in consideration of its unique offset.

As shown in FIG. IA, when MPs 12 and 14 transmit beacon signals according to the same Target Beacon Transmission Time (TBTT) offset, the transmitted beacon signals do not collide with each other if MPs 12 and 14 maintain a specific distance from each other. However, if the MP 14 moves closer to MP 12, the transmitted beacon signals collide with each other as a result of MPs 12 and 14using the same TBTT offset.

As shown in FIG. IB, when a new MP 16 joins the network, collision between beacon signals occurs. For example, the MP 16 receives beacon signals from the MP 12 and the MP 14. Here, the MP 12 and the MP 14 transmits beacon signals according to the same TBTT offset. Thus, the MP 16 may not sense the presence of the MP 12 or the MP 14.

FIG. 2 illustrates the format of a probe beacon timing element according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the probe beacon timing element is used for synchronization between MPs and the MPs either periodically or non-periodically transmit the probe beacon timing element. Thus, the probe beacon timing element includes the addresses of adjacent nodes (e.g., within 2 hops) and beacon timing information. Fields of the probe beacon timing element according to an exemplary embodiment of the present invention are also added to the probe beacon timing element.

The probe beacon timing element is formed by adding a tentative beacon timing-of-self field 102, a last byte of Medium Access Control (MAC) address- of-self field 104, and an original beacon timing-of-self field 106 to a general probe beacon timing element format.

Upon sensing a change in a network topology or the joining of a new MP, an MP selects a TBTT offset that is different from that of an adjacent MP. The selected TBTT offset is indicated by the tentative beacon timing-of-self field 102. The TBTT offset of the tentative beacon timing-of-self field 102 may be set according to a network environment, e.g., at the same time as a Delivery Traffic Indication Message (DTIM) time period. After the DTIM frame, buffered broadcast traffic and multicast traffic are transmitted. The last byte of MAC address-of-self field 104 indicates the MAC address of a source MAP or MP.

The original beacon timing-of-self field 106 indicates the original TBTT offset that is used by the source MAP or MP prior to the change in the TBTT offset.

As mentioned above, an MP or MAP may transmit beacon timing element information to which the fields 102, 104, and 106 are added at an arbitrary time while periodically transmitting beacon timing element information in which the fields 102, 104, and 106 are omitted. Here, a TBTT offset selected, except for TBTT offsets of adjacent nodes (e.g., within 2 hops) previously recognized by an MP or MAP, is recorded in the tentative beacon timing-of-self field 102. Thus, the MP or MAP can, using the probe beacon timing element, determine whether or not beacon signals collide with each other when using the original TBTT offset.

FIG. 3 illustrates the format of a probe response beacon timing element according to an exemplary embodiment of the present invention.

Referring to FIG. 3, if an MP receiving probe beacon timing element information detects a beacon signal collision, it uses the probe response beacon timing element for transmitting a probe beacon transmission request, together with newly selected TBTT offset information, to a transmission MP. The newly selected TBTT offset information is beacon timing information that prevents beacon signals from colliding with each other, and is included in the probe response beacon timing element.

FIG. 4 is a flowchart illustrating a process in which a reception MP processes a beacon signal according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the reception MP collects beacon timing information and MAC address information regarding adjacent MPs from a transmission MP by receiving a beacon timing element in step 302. In step 304, the reception MP checks if the first MAC address is the same as a source MAC address to determine whether the received beacon timing element is a general beacon timing element or a probe beacon timing element. The probe beacon timing element was discussed above with respect to FIG. 2. If the first MAC address is the same as the source MAC address, the first MAC address is the last byte of MAC address-of-self field 104 as disused above with respect to FIG. 2. Thus, the received beacon timing element is the probe beacon timing element including a TBTT offset. However, if the first MAC address is not the same as the source MAC address, the received beacon timing element is a general beacon timing element. Thus, the reception MP goes to step 308 to perform general beacon signal processing .

In step 306, the reception MP determines whether beacon timing-of-self information included in the received beacon timing element is the same as beacon timing information included in the original beacon timing information of adjacent nodes. If the beacon timing-of-self information is not the same as beacon timing included in the original beacon timing information, the reception MP goes to step 308.

If the original beacon timing information of the transmission MP is the same as the beacon timing information of the reception MP in step 306, the reception MP goes to step 310 to select tentative beacon timing-of-self information included in the received probe beacon timing element as a TBTT offset. In step 312, the reception MP transmits the probe response beacon timing element including the selected TBTT offset. Here, the reception MP may select a tentative beacon timing-of-self that is not the same as the original beacon timing of other nodes, instead of tentative beacon timing-of-self transmitted by the transmission MP.

As described above, according to exemplary embodiments of the present invention, by non-periodically transmitting probe beacon timing element information in addition to periodically transmitting conventional beacon timing element information in a wireless Local Area Network (LAN) mesh network, collisions between beacon signals can be detected or prevented.

Exemplary embodiments of the present invention may be embodied in a general-purpose computer by running a program from a computer-readable medium, including but not limited to storage media such as magnetic storage media (ROMs, RAMs, floppy disks, magnetic tapes, and the like), optically readable media (CD-ROMs, DVDs, and the like), and carrier waves (transmission over the internet).

While certain exemplary embodiments of the invention has have been shown and described hereinwith reference to a certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.

Claims

WHAT IS CLAIMED IS:
1. A method for transmitting beacon timing information from a transmission node in a wireless Local Area Network (LAN) mesh network, the method comprising the steps of: transmitting, by each of a plurality of nodes, a beacon signal comprising a unique offset within a beacon signal transmission time period: periodically transmitting, by the transmission node, beacon timing information comprising a first unique offset within the beacon signal transmission time period; setting a second offset different from the first offset; and transmitting probe beacon timing information including the first offset and the second offset.
2. The method of claim 1, further comprising the step of receiving, by the transmission node, offset information of its adjacent nodes.
3. The method of claim 2, wherein the probe beacon timing element information includes the second offset different from offsets of adjacent nodes of the transmission node, the Medium Access Control (MAC) address of the transmission node, and the first offset.
4. A method for receiving beacon timing information at a reception node in a wireless Local Area Network (LAN) mesh network, the method comprising the steps of: receiving the beacon timing information from a transmission node; detecting whether the received beacon timing information includes the Medium Access Control (MAC) address of the transmission node; if the received beacon timing information includes the Medium Access Control (MAC) address of the transmission node, detecting a first offset and a second offset that are the beacon timing information of the transmission node; checking if the second offset is the same as offsets of other transmission nodes; and if the second offset is the same as offsets of other transmission nodes, selecting the first offset to transmit a beacon timing information retransmission request.
5. The method of claim 4, wherein the first offset is set by the transmission node so that it can be distinguished from unique offsets of other nodes.
6. The method of claim 4, wherein the second offset is set prior to the first offset so that a beacon signal can be transmitted at an interval.
7. The method of claim 4, wherein the beacon timing information retransmission request includes the MAC address of the reception node.
8. A computer-readable recording medium storing a program for implementing a method for transmitting beacon timing information from a transmission node in a wireless Local Area Network (LAN) mesh network, the method comprising the steps of: transmitting, by each of a plurality of nodes, a beacon signal comprising a unique offset within a beacon signal transmission time period: periodically transmitting, by the transmission node, beacon timing information comprising a first unique offset within the beacon signal transmission time period; setting a second offset different from the first offset; and transmitting probe beacon timing information including the first offset and the second offset.
9. The method of claim 8, further comprising the step of receiving, by the transmission node, offset information of its adjacent nodes.
10. The method of claim 9, wherein the probe beacon timing element information includes the second offset different from offsets of adjacent nodes of the transmission node, the Medium Access Control (MAC) address of the transmission node, and the first offset.
11. A computer-readable recording medium storing a program for implementing a method for receiving beacon timing information at a reception node in a wireless Local Area Network (LAN) mesh network, the method comprising the steps of: receiving the beacon timing information from a transmission node; detecting whether the received beacon timing information includes the Medium Access Control (MAC) address of the transmission node; if the received beacon timing information includes the Medium Access Control (MAC) address of the transmission node, detecting a first offset and a second offset that are the beacon timing information of the transmission node; checking if the second offset is the same as offsets of other transmission nodes; and if the second offset is the same as offsets of other transmission nodes, selecting the first offset to transmit a beacon timing information retransmission request.
12. The method of claim 11, wherein the first offset is set by the transmission node so that it can be distinguished from unique offsets of other nodes.
13. The method of claim 11, wherein the second offset is set prior to the first offset so that a beacon signal can be transmitted at an interval.
14. The method of claim 11, wherein the beacon timing information retransmission request includes the MAC address of the reception node.
PCT/KR2006/003559 2005-09-07 2006-09-07 Method for transmitting and receiving beacon information in wireless lan mesh network WO2007029973A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US71427105P true 2005-09-07 2005-09-07
US60/714,271 2005-09-07
KR10-2006-0064929 2006-07-11
KR1020060064929A KR101269853B1 (en) 2005-09-07 2006-07-11 Method for transmitting and receiving beacon information in wireless lan mesh network

Publications (1)

Publication Number Publication Date
WO2007029973A1 true WO2007029973A1 (en) 2007-03-15

Family

ID=37836050

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2006/003559 WO2007029973A1 (en) 2005-09-07 2006-09-07 Method for transmitting and receiving beacon information in wireless lan mesh network

Country Status (1)

Country Link
WO (1) WO2007029973A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007063427A3 (en) * 2005-05-26 2007-11-29 Nokia Corp Method, apparatus and article for collisionless beacon transmission in wireless networks
WO2009053480A1 (en) * 2007-10-25 2009-04-30 Siemens Aktiengesellschaft Communication method, system and network nodes in a low power communication network

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060018298A1 (en) * 2004-07-21 2006-01-26 Samsung Electronics Co., Ltd. System for dynamically shifting beacons in distributed wireless network and method thereof
US20060092909A1 (en) * 2004-10-29 2006-05-04 Jin-Meng Ho System and method for access and management of beacon periods in distributed wireless networks

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060018298A1 (en) * 2004-07-21 2006-01-26 Samsung Electronics Co., Ltd. System for dynamically shifting beacons in distributed wireless network and method thereof
US20060092909A1 (en) * 2004-10-29 2006-05-04 Jin-Meng Ho System and method for access and management of beacon periods in distributed wireless networks

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
IQBAL M.M., GONDAL I., DOOLEY L.: "Optimizing the beacon exchange rate for proactive autonomic configuration in ubiquitous MANETs", WIRELESS AND OPTICAL COMMUNICATIONS NETWORKS, 2003. WOCN 2005. SECOND IFIP INTERNATIONAL CONFERENCE, 6 March 2005 (2005-03-06) - 8 March 2005 (2005-03-08), pages 340 - 345, XP010801910 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007063427A3 (en) * 2005-05-26 2007-11-29 Nokia Corp Method, apparatus and article for collisionless beacon transmission in wireless networks
US9007954B2 (en) 2005-05-26 2015-04-14 Nokia Corporation Beacon transmission for wireless networks
WO2009053480A1 (en) * 2007-10-25 2009-04-30 Siemens Aktiengesellschaft Communication method, system and network nodes in a low power communication network
US8477671B2 (en) 2007-10-25 2013-07-02 Siemens Aktiengesellschaft Communication method, system and network nodes in a low power communication network

Similar Documents

Publication Publication Date Title
CN101803309B (en) Method and system of routing in a utility smart-grid network
US8798084B2 (en) Increasing reliability and reducing latency in a wireless network
KR100605896B1 (en) Route path setting method for mobile ad hoc network using partial route discovery and mobile terminal teerof
US7911978B1 (en) Adaptive topology discovery in communication networks
US8738013B2 (en) 802.11 mesh architecture
CN101208974B (en) Method for optimizing channel scanning function in telecommunication network of mobile terminal
US8605657B2 (en) Mesh routing method and mesh routing apparatus in beacon enabled wireless AD-HOC networks
US7848223B2 (en) Redundantly connected wireless sensor networking methods
CA2488204C (en) System and method for forming, maintaining and dynamically reconfigurably routing in an ad-hoc network
US7961710B2 (en) Apparatus and method for setting multi-path
US9565633B2 (en) Opportunistic information forwarding using wireless terminals in the internet-of-things
JP4005085B2 (en) Mobile ad hoc network with intrusion detection function and related method
US7860049B2 (en) Method for controlling communication route of wireless multi-hop network system and communication terminal
CN102067515B (en) Collision mitigation for multicast transmission in wireless local area networks
US7966036B2 (en) Wireless LAN device and communication mode switching method
US20060215588A1 (en) Energy-efficient network protocol and node device for sensor networks
US20020141368A1 (en) Method and apparatus for connecting a wireless lan to a wired lan
US6704293B1 (en) Broadcast as a triggering mechanism for route discovery in ad-hoc networks
US8300626B2 (en) Path shortening in a wireless mesh network
US7961627B2 (en) Method and system for generating antenna selection signals in OFDM transceivers with fewer RF chains than antennas in MIMO wireless networks
US9842202B2 (en) Device proximity
RU2316125C2 (en) Method and device for finding adjacent units within piconet communication system
JP2005536118A (en) Mobile ad hoc network with intrusion detection function and related method
US7787361B2 (en) Hybrid distance vector protocol for wireless mesh networks
US20040141511A1 (en) Bridging between a bluetooth scatternet and an ethernet LAN

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application
DPE1 Request for preliminary examination filed after expiration of 19th month from priority date (pct application filed from 20040101)
NENP Non-entry into the national phase in:

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 06783782

Country of ref document: EP

Kind code of ref document: A1