Abstract:
An apparatus, method, and computer readable medium thereof for simultaneously establishing links with a plurality of nodes in a wireless network are provided. A processing module determines whether a mesh network configuration message of the apparatus has space to packet an information element and determines whether to transmit a Neighbor Link Establishment information element to one of the nodes. If the mesh network configuration message has space to packet an information element and the Neighbor Link Establishment information element needs to be transmitted to one of the nodes, the Neighbor Link Establishment information element will be packeted into the mesh network configuration message. Finally, a transmission module transmits the mesh network configuration message to the nodes in order to solve the problem of increasing time during link establishment and avoid deadlock among the nodes when the apparatus of the prior art establishes links with the nodes simultaneously.

Description:
This application claims the benefit of priority based on Taiwan Patent Application No. 095145691 filed on Dec. 7, 2006 of which the contents are incorporated herein by reference in its entirety. 
     CROSS-REFERENCES TO RELATED APPLICATIONS 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus, and a method for simultaneously establishing links with a plurality of nodes in a wireless network. The method can be implemented by a computer program which is stored in a computer readable medium. 
     2. Descriptions of the Related Art 
     With the rapid development of the computer network, various broadband services are now essential to the information industry. However, only part of computer users in the whole world can use high speed wired broadband services, such as the digital subscribe line (DSL) and the cable broadband access. From network telecommunication service providers&#39; point of view, they desire to expand the coverage range of the broadband network. However, the related infrastructure costs for building the wired network make the providers move back. Broadband wireless techniques, hence, become an important solution. In light of communication distance, the current techniques of the wireless network can be classified into the wide area network (WAN), the metropolitan area network (MAN), the local area network (LAN), and the personal area network (PAN). 
     IEEE 802.16, worldwide interoperability for microwave access (WiMax), is a newly developing wireless transmission standard. The original establishing objective is to set up a radio standard of the metropolitan network to provide a wireless broadband connection technique of “the last mile” for the telecommunication industry. After continuously improved by the researchers of IEEE 802.16, more market requests can be supported now, such as various mobile and high speed broadband applications. Furthermore, comparing with IEEE 802.11, i.e., Wi-Fi and the third generation mobile communication (3G) technique, IEEE 802.16 has the advantages of larger network bandwidth, lower construction cost, better service quality, better expansibility, and extending the usage mode of a Wi-Fi hot spot. 
     IEEE 802.16 defines two operation modes. One is the point to multipoint (PMP) mode which is used in the aforementioned wireless broadband connection technique of “the last mile” to replace the conventional fixed network, such as the asymmetric digital subscriber line (ADSL) or the T1 subscriber line. The other operation mode is the mesh mode which provides a high speed and reliable backbone network. After several years&#39; research on the PMP mode, the current techniques are very mature and already applied widely. Although the mesh mode has many advantages, it involves a more complicated technique and does not mature yet. Hence, the mesh mode still requires a lot of development. 
     As shown in  FIG. 1 , a conventional wireless network  1  operating under the mesh operation mode of IEEE 802.16 is disclosed. The wireless network  1  comprises a base station  101 , a plurality of nodes  103 ,  105 , . . . ,  113  and an apparatus  115  which is about to join the wireless network  1 . The base station  101  establishes the wireless network  1 . The nodes  103 ,  105 , . . . ,  113  are various kinds of communication apparatuses for transmitting and routing data. The apparatus  115  has an effective connection range  100  which covers the nodes  107 ,  111 ,  113 , and does not cover the nodes  103 ,  105 ,  109 . That is, the nodes  107 ,  111 ,  113  can separately establish a link with the apparatus  115  for communication. When the apparatus  115  intends to join the wireless network  1 , a network entry process is executed so that the apparatus  115  can join the wireless network  1  smoothly. After the network entry process is executed completely, the apparatus  115  logs into the base station  101 . Next, the apparatus  115  performs a link establishment process to establish links between the apparatus  15  and the nodes  107 ,  111 ,  113  covered by the effective connection range  100 . After the apparatus  15  establishes links with the nodes  107 ,  111 ,  113 , the apparatus  115  can use resources and channels of the wireless network  1  to communicate with the neighboring nodes  107 ,  111 ,  113 . In other words, the link must be established before data can be transmitted. When the apparatus  115 , a starting node, separately establishes links with nodes  107 ,  111 ,  113 , receiving nodes, there are three required steps to ensure the links to be established correctly. Messages transmitted in these three-step procedures all comprise Neighbor Link Establishment information elements (IEs). The Messages can be called Neighbor Link Establishment messages, which can be divided as a challenge message, a challenge response message, and an accept message. 
     Taking the link established between the apparatus  115  and the node  107  as an example, the apparatus  115  transmits a challenge message  102  to the node  107  first. After the node  107  receives the challenge message  102 , an authentication procedure is performed to confirm that the node  107  is allowed to establish a link with the apparatus  115 . After the authentication procedure is passed, the node  107  transmits a challenge response message  108  to the apparatus  115  to establish a unidirectional link from the node  107  to the apparatus  115 . After the apparatus  115  receives the challenge response message  108 , the authentication procedure is also performed to confirm that the apparatus  115  is allowed to establish a link with the node  107 . After the authentication procedure is passed, the apparatus  115  transmits an accept message  114  to the node  107  to establish a unidirectional link from the apparatus  115  to the node  107 . 
     Based on the current IEEE 802.16 standard, the apparatus  115  can only establish a bidirectional link with one node at a time. As shown in  FIG. 1 , after the apparatus  115  establishes the link with the node  107 , the apparatus  115  can establish bidirectional links with the node  111  and the node  113  one by one based on the aforementioned three-step procedure. That is, the apparatus  115  separately transmits challenge messages  104 ,  106  to nodes  111 ,  113 . The nodes  111 ,  113  separately transmit challenge response messages  110 ,  112  to the apparatus  115  to establish unidirectional links  119 ,  121 . Finally, the apparatus  115  separately transmits accept messages  116 ,  118  to nodes  111 ,  113  to establish unidirectional links  125 ,  127 . 
     Consequently, the apparatus  115  and nodes  107 ,  111 ,  113  can establish bidirectional links through the aforementioned series of link establishment operations. Then, the apparatus  115  can transmit data with the nodes  107 ,  111 ,  113  via the links. The aforementioned messages related to link establishment, such as the challenge messages  102 ,  104 ,  106 , the challenge response messages  108 ,  110 ,  112 , and the accept messages  114 ,  116 ,  118 , are transmitted through mesh network configuration message (MSH-NCFG). 
     In IEEE 802.16 standard, a challenge message comprises a Neighbor Link Establishment information element with an action code field set to 0, a reserve field, and a neighborhood authentication value field. The challenge response message comprises a Neighbor Link Establishment information element with an action code field set to 1, a reserve field, a neighborhood authentication value field, and a Link ID. The accept message comprises a Neighbor Link Establishment information element with an action code field set to 2, a reserve field, and a Link ID. 
     Since the authentication procedure will not be performed after the accept messages  114 ,  116 ,  118  are transmitted, the accept messages  114 ,  116 ,  118  do not confirm the fields in the starting node and the receiving node. Such a process causes that the apparatus  115  only can establish a bidirectional link with one node at a time. That is, the apparatus  115  is allowed to establish the link with one of the nodes  111 ,  113  only when the bidirectional link with the node  107  is established. This causes that the link establishment process monopolizes resources. In other words, before the apparatus  115  completes the aforementioned three-step procedure for establishing the bidirectional link with one node, other nodes can not proceed to establish their links. If nodes establish links simultaneously, it is possible to cause a deadlock condition during the link establishing process among a group of nodes, and thus it is unable to build any links in the wireless network with the mesh mode. 
     If the apparatus  115  establishes links with the nodes  107 ,  111 ,  113  simultaneously, the nodes  107 ,  111 ,  113  can not distinguish that the link ID in the accept message is for which one of the nodes  107 ,  111 ,  113  because the accept message only comprises the link ID but does not comprise the neighborhood authentication value field. As a result, the apparatus  115  confuses the nodes  107 ,  111 ,  113 , and the wireless network  1  operating in the mesh mode of IEEE 802.16 will collapse. 
     Since the apparatus  115  only can establish a link with one of nodes covered by the effective connection range  100  at a time, the time for establishing links with all nodes will be long, especially when the number of nodes covered by the effective connection range  100  increases. Furthermore, the link establishing process monopolizes resources. If nodes establish links simultaneously, the deadlock condition may occur. Consequently, how to make the apparatus  115  establish links with all nodes covered by the effective connection range  100  simultaneously to reduce the establishing time and to avoid the deadlock condition is still a problem for the industry to solve. 
     SUMMARY OF THE INVENTION 
     One objective of this invention is to provide a method for an apparatus to simultaneously establish links with a plurality of nodes in a wireless network. The method comprises the following steps: determining whether a mesh network configuration message of the apparatus has space to packet an information element; determining whether a Neighbor Link Establishment information element needs to be transmitted to one of the nodes; packeting the Neighbor Link Establishment information element into the mesh network configuration message if the mesh network configuration message has space to packet an information element, and the Neighbor Link Establishment information element needs to be transmitted to one of the nodes; and transmitting the mesh network configuration message. 
     A further objective of the invention is to provide a computer readable medium storing a computer program for an apparatus to execute a method for simultaneously establishing links with a plurality of nodes in a wireless network. The method comprises the following steps: determining whether a mesh network configuration message of the apparatus has space to packet an information element; determining whether a Neighbor Link Establishment information element needs to be transmitted to one of the nodes; packeting the Neighbor Link Establishment information element into the mesh network configuration message if the mesh network configuration message has space to packet an information element, and the Neighbor Link Establishment information element needs to be transmitted to one of the nodes; and transmitting the mesh network configuration message. 
     Yet a further objective of the invention is to provide an apparatus capable of simultaneously establishing links with a plurality of nodes in a wireless network. The network nodes comprise a processor and a transmission module. The processor determines whether a mesh network configuration message of the apparatus has space to packet an information element, determines whether the apparatus needs to transmit a Neighbor Link Establishment information element to one of the nodes, and packets the Neighbor Link Establishment information element into the mesh network configuration message if the mesh network configuration message has space to packet an information element and the apparatus needs to transmit the Neighbor Link Establishment information element to one of the nodes. The transmission module transmits the mesh network configuration message. 
     The present invention is capable of packeting the information elements transmitted to each of the nodes into one mesh network configuration message and adding corresponding identification into the Neighbor Link Establishment information element for each node. Therefore, the drawbacks of the prior art that establishing links take time and might cause deadlock can be solved. The present invention can enhance the overall performance, deployment, and usability under a mesh mode network of IEEE 802.16, especially when there are a larger number of nodes needing to establish links. 
     The detailed technology and preferred embodiments implemented for the subject invention are described in the following paragraphs accompanying the appended drawings for people skilled in this field to well appreciate the features of the claimed invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram illustrating a conventional wireless network in a mesh mode of IEEE 802.16; 
         FIG. 2  is a schematic diagram illustrating a wireless network of a first embodiment of the present invention; 
         FIG. 3  is a schematic diagram of an apparatus of the first embodiment of the present invention; and 
         FIG. 4  is a flow chart of a second and a third embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in  FIG. 2 , a first embodiment of the present invention is a wireless network  2  in a mesh mode of IEEE 802.16. The wireless network  2  comprises a base station  201 , a plurality of nodes  203 ,  205 , . . . ,  213 , and an apparatus  215  which just finishes a network entry process. As shown in  FIG. 3 , the apparatus  215  comprises a transmission module  2151 , a processor  2153 , and a receiving module  2155 . The nodes  203 ,  205 , . . . ,  213 , and the apparatus  215  can be a gateway, a router, or a terminal apparatus that transmit data in the mesh mode of IEEE 802.16. 
     The apparatus  215  has an effective connection range  200  which covers the nodes  207 ,  211 ,  213  and does not cover the nodes  203 ,  205 ,  209 . After the apparatus  215  completes the network entry process and joins the wireless network  2 , the apparatus  215  starts to perform a link establishing process with the nodes  207 ,  211 ,  213 . 
     The apparatus  215  initially uses a mesh network configuration message  202  to transmit various Neighbor Link Establishment information elements, such as a challenge message, a challenge response message, or an accept message, to the nodes  207 ,  211 ,  213 . The formats of these messages are defined by IEEE 802.16 standard, and thus no unnecessary detail is given here. Before the apparatus  215  transmits the mesh network configuration message  202 , the processor  2153  determines whether the mesh network configuration message  202  has space to packet an information element. If yes, the processor  2153  continues to determine whether the apparatus  215  needs to transmit a Neighbor Link Establishment information element to one of the nodes  207 ,  211 ,  213 . If the apparatus  215  needs to transmit a Neighbor Link Establishment information element to one of the nodes  207 ,  211 ,  213 , that means the apparatus  215  does not establish the links with the nodes  207 ,  211 ,  213  yet. The processor  2153  then packets the Neighbor Link Establishment information element into the mesh network configuration message  202 . The Neighbor Link Establishment information element is transmitted to the nodes  207 ,  211 ,  213  via the mesh network configuration message  202 . If there is no space for the mesh network configuration message  202  to packet the Neighbor Link Establishment information element, the transmission module  2151  will transmit the mesh network configuration message  202  directly. If the processor  2153  determines that the apparatus  215  does not need to transmit a Neighbor Link Establishment information element to one of the nodes  207 ,  211 ,  213 , that means the apparatus  215  and the nodes  207 ,  211 ,  213  have established links already. Under such circumstances, the transmission module  2151  may transmit other mesh network configuration messages  202 . The receiving module  2155  is configured to receive returned data transmitted by the nodes  207 ,  211 ,  213  covered in the effective connection range  200 . 
     The above-mentioned operations will be further recited in the following descriptions. When the processor  2153  determines that the mesh network configuration message  202  still has space to packet the an information element, and the apparatus  215  has to transmit a challenge message to the node  207 , the processor  2153  will packet the challenge message for the node  207  into the mesh network configuration message  202 . Next, if the processor  2153  continues to determine that the mesh network configuration message  202  still has space to packet one more Neighbor Link Establishment information element, and the apparatus  215  has to transmit an accept message to the node  213 , the processor  2153  will packet the accept message for the node  213  into the mesh network configuration message  202 . After that, if the mesh network configuration message  202  has no more space to packet any information element or the apparatus  215  has no Neighbor Link Establishment information element required to be transmitted to the nodes  207 ,  211 ,  213 , the transmission module  2151  will transmit the mesh network configuration message  202 . 
     Since the mesh network configuration message  202  is transmitted by broadcasting, the nodes  207 ,  211 ,  213  covered in the effective connection range  200  can receive the mesh network configuration message  202 . No matter the packeted information element in the mesh network configuration message  202  is the challenge message for the node  207 , the accept message for the node  213 , or other messages with Neighbor Link Establishment information elements, the Neighbor Link Establishment information elements packeted into the mesh network configuration message  202  comprise the identification of the apparatus  215  and the identifications of the destination nodes. For example, the challenge message for the node  207  comprises the identification of the apparatus  215  and the identification of the node  207 , the accept message for the node  213  comprises the identification of the apparatus  215  and the identification of the node  213 . This allows the nodes  207 ,  211 ,  213  to find out which Neighbor Link Establishment information element is for itself, and to ignore other Neighbor Link Establishment information elements for other nodes. 
     A second embodiment of the present invention is a method for an apparatus to simultaneously establish links with a plurality of nodes in a wireless network. The method is applied to the apparatus  215  described in the first embodiment. The method of the second embodiment can be performed by a computer program which is stored in a computer readable medium. 
     As shown in  FIG. 4 , the method begins at step  401  in which the computer program comprises code for the apparatus  215  preparing to establish links. Step  403  is then executed in which the computer program comprises code for the processor  2153  determining whether a mesh network configuration message of the apparatus  215  has space to packet an information element. If yes, step  405  is executed in which the computer program comprises code for the processor  2153  continuing to determine whether a Neighbor Link Establishment information element needs to be transmitted to one of the nodes. If the apparatus  215  needs to transmit a Neighbor Link Establishment information element to one of the nodes, step  407  is executed in which the computer program comprises code for the processor  2153  packeting the Neighbor Link Establishment information element into the mesh network configuration message. After step  407  is executed, step  403  is executed again in which the processor  2153  determines whether a mesh network configuration message of the apparatus  215  has space to packet another information element. 
     If there is no space for the mesh network configuration message to packet an information element in step  403 , step  409  is executed in which the computer program comprises code for a transmission module  2151  transmitting the mesh network configuration message. Furthermore, if the processor  2153  determines that the apparatus  215  does not need to transmit a Neighbor Link Establishment information element to one of the nodes in step  405 , step  409  is also executed. 
     In the above steps, step  403  and step  405  do not have to be executed in the fixed sequence. Although, the second embodiment illustrates that step  403  is executed first and step  405  is executed later, step  403  and step  405  can be interchanged such that after step  405  is executed, step  403  continues to be executed if yes in step  405 . In other embodiments, step  403  and step  405  can be executed together. That is, when the mesh network configuration message of the apparatus  215  is determined to have space to packet an information element and there is a Neighbor Link Establishment information element required to be transmitted, step  407  is executed. 
     In addition to the steps shown in  FIG. 4 , the computer program of the second embodiment also has further code to execute all of the operations or functions recited in the first embodiment. Those skilled in this field can straightforwardly realize how the second embodiment performs these operations and functions based on the above descriptions of the first embodiment, and thus no unnecessary detail is given here. 
     A third embodiment of the invention is another method for an apparatus to simultaneously establish links with a plurality of nodes in a wireless network. For a more detailed description, the method of the third embodiment is similar to the method of the second embodiment. 
     At first, step  401  is executed for preparing to establish links. Step  403  is executed for determining whether a mesh network configuration message has space to packet an information element. If yes, step  405  is executed for determining whether a Neighbor Link Establishment information element needs to be transmitted to one of the nodes. If the Neighbor Link Establishment information element needs to be transmitted to one of the nodes, step  407  is executed for packeting the Neighbor Link Establishment information element into the mesh network configuration message. After step  407  is executed, step  403  is executed again for determining whether a mesh network configuration message has space to packet another information element. 
     If there is no space for the mesh network configuration message to packet an information element in step  403 , step  409  is executed for transmitting the mesh network configuration message. Furthermore, if there is no need to transmit the Neighbor Link Establishment information element to one of the nodes in step  405 , step  409  is also executed. 
     Similar to the second embodiment, step  403  and step  405  do not have to be executed in an absolute order. Those skilled in the art can straightforwardly realize the corresponding steps or operations of the third embodiment according to the descriptions of the second embodiment, and thus no necessary detail is given here. 
     In addition to the steps shown in  FIG. 4 , the computer program of the third embodiment can has code to execute all of the operations or functions recited in the first embodiment. Those skilled in this field can straightforwardly realize how the third embodiment performs these operations and functions based on the above descriptions of the first embodiment, and thus no unnecessary detail is given here. 
     The above-mentioned computer readable medium can be a floppy disk, a hard disk, an optical disc, a flash disk, a tape, a database accessible from a network or a storage medium with the same functionality that can be easily thought by people skilled in the art. 
     Accordingly, the present invention can packet the Neighbor Link Establishment information elements that have to be transmitted to nodes into a mesh network configuration message and add the identification of the apparatus and the identification of the nodes into the Neighbor Link Establishment information element so that the nodes can find out the required Neighbor Link Establishment information element in the mesh network configuration message. With peroforming the aforementioned method by slightly amending IEEE 802.16 specification, the required time for establishing links among all nodes covered with the effective connection range of the apparatus can be reduced successfully. Furthermore, the deadlock conditions, when links between nodes and the apparatus are established, can be avoided so that when the apparatus requests to enter the mesh network of IEEE 802.16, the user will never fall into a painful waiting or an awkward situation of not being able to connecting to the base stations. Users can obtain an unprecedented use experience in easily add their apparatuses, such as laptops or various kinds of mobile electronic apparatuses, to the mesh network of IEEE 802.16. The capability of easily connecting to the network to obtain the required information in the future city is of great news for users. 
     The above disclosure is related to the detailed technical contents and inventive features thereof. People skilled in this field may proceed with a variety of modifications and replacements based on the disclosures and suggestions of the invention as described without departing from the characteristics thereof. Nevertheless, although such modifications and replacements are not fully disclosed in the above descriptions, they have substantially been covered in the following claims as appended.