KR20200027191A - Wireless network channel allocation method and multi-hop wireless network system using the same - Google Patents

Abstract

The present invention relates to a network technique, and more particularly, to a technique for dynamically allocating channels so that a mesh node having the limited number of wireless transmission/reception channels on a wireless mesh network can effectively use multiple channels. According to the present invention, a method for allocating channels on a wireless network is configured to comprise: an information collection step of receiving or collecting node information including available channel information of each node on a wireless network; a connection relation calculation step of calculating multiple connection relations of connection links between nodes through the collected node information; a collision relation calculation step of calculating channel collision relations due to interference of the connection links between nodes according to the calculated multiple connection relations; a channel allocation step of allocating channels to the connection links between nodes by referring to the collision relations by the collision relation calculation step; and a step of providing a channel allocated to each link to each node.

Description

Network channel assignment method {WIRELESS NETWORK CHANNEL ALLOCATION METHOD AND MULTI-HOP WIRELESS NETWORK SYSTEM USING THE SAME}

The present invention relates to a network technology, and relates to a technology for dynamically allocating a channel so that a mesh node having a limited number of wireless transmission / reception channels on a wireless mesh network can effectively use multiple channels.

Wireless mesh networks (WMNs) have been widely studied for the purpose of expanding an area that can connect to the Internet through a multi-hop configuration. Such a wireless mesh network has advantages such as rapid introduction, low installation cost, high scalability and flexibility in that it does not depend on wired network installation. This advantage helps to provide a low cost internet connection in areas where it is difficult to expand the wired network. In addition, it can be used to increase the transmission capacity and reduce the node density in one cell through fast Internet access point expansion in a dense area.

A typical example of such a wireless mesh network can be found in the standardization activities being conducted in IEEE. WLAN and WiMAX technologies, which are currently standardized in IEEE 802.11 and 802.16 Working Groups (WGs), deal with wireless mesh networks. In 802.11 WG, in the Extended Service Set (ESS) Mesh Networking (IEEE 802.11s) Task Group (TG), in the Media Access Control (MAC) layer, the mesh AP ( It is considering a method of selecting a path through an access point and passing data. Here, the Mesh AP forms a wireless backbone network so that data generated by nodes receiving the service from the AP can be delivered to the Internet access point to receive the Internet service. The WiMAX standard and the Multi-hop Relay (IEEE 802.16a / j) work group deal with protocol definition for mesh nodes and extension of coverage through multi-hop transmission.

In such a wireless mesh network, multiple channels that do not overlap can be used to improve system performance. For example, the IEEE 802.11b / g and 802.11a standards provide 3 and 12 non-overlapping channels, respectively. Since multiple channels allow simultaneous transmission between adjacent nodes, it helps to improve transmission performance and delay.

In addition, as the price of wireless transceivers decreases, multiple transceivers can be used for one mesh node. In fact, products with multiple transceivers are commercially available. However, it is impossible to use all the multiple channels at the same time because the number of transceivers mounted is limited due to price problems. Therefore, in order to maximize the use of multiple channels, there is a need for a method of allocating multiple channels so as not to cause mutual interference.

In order to use the channel effectively, it is necessary to consider the interference experienced by the different channels at each node. This is because each node experiences different channel interference, and therefore, a channel in a good state is different depending on the node. Therefore, a method is needed for each node to measure the signal noise of the channel and select a channel with low interference. Currently, the transceiver can only transmit or receive at one time, and has the disadvantage of requiring time to switch to different channels.

Korean Registered Patent Publication No. 10-0712344 Korean Registered Patent Publication No. 10-0995531 Korean Patent Publication No. 10-2008-0101858

The present invention was devised to solve this problem, and its purpose is to provide a channel allocation method of a wireless network and a multi-hop wireless network system using the same so that multiple channels can be effectively used through switching even through a limited wireless transceiver. To provide.

As a means to achieve the above object,

An information collection step of receiving or collecting node information including available channel information of each node on the wireless network; A connection relationship calculation step of calculating a multi-connection relationship of connection links between nodes through the collected node information; A collision relationship calculating step of calculating a channel collision relationship due to interference of a connection link between nodes according to the calculated multi-connection relationship; A channel allocation step of allocating a channel to a connection link between nodes with reference to the collision relationship by the collision relationship calculation step; Providing a channel allocated to each link to each node; Comparing old version software information with new version software information; Determining different parts of the old version and the new version software; And recording a new version part for the different parts in a corresponding area of the old version software.

In addition, the software of the old version and the new version is composed of several areas, and an identification key is assigned to each area, and it is characterized in that different parts of the old version and the new version are judged by comparing the identification keys.

In addition, the determination of different parts of the old version and the new version is characterized by comparing each version information.

In addition, the information collecting step is characterized in that it is received or collected through the relay between each node.

In addition, the connection relationship calculating step is characterized in that: generating multiple graphs having multiple channels for multiple transmission and reception between nodes.

As described above, the channel allocation method of the wireless network according to the present invention and the multi-hop wireless network system using the same allow the multiple channels to effectively use multiple channels through switching even through a restricted wireless transceiver, and the channel of different nodes. It has an advantage that a channel can be effectively used in a multi-hop mesh network while minimizing interference between channels in consideration of interference.

1 is a schematic diagram schematically showing a multi-hop wireless network system according to an exemplary embodiment of the present invention.
2 is a block diagram schematically showing a channel allocation module according to an exemplary embodiment of the present invention.
3 is a schematic diagram schematically showing a multi-graph according to an exemplary embodiment of the present invention.
4 is a schematic diagram schematically showing a multi-channel collision graph according to an exemplary embodiment of the present invention.
5 is a schematic diagram schematically showing a multi-channel collision graph and sub-graphs according to one preferred embodiment of the present invention.
6 is a schematic diagram schematically showing channel allocation results for each node by a sub-graph list coloring (SLC) algorithm and channel allocation results for each node by a k-GL algorithm according to an exemplary embodiment of the present invention.
7 is an example of signal flow of a process in which a download processing module loads a file storing an identification key for each area from an embedded device using data communication.
8 is an example of a signal flow of a process in which a download processing module loads a file storing an identification key for each area from an embedded device using data communication through an OTA method.
9 is an example of a signal flow of a process in which a download processing module partially downloads data of an area changed to an embedded device using data communication.
10 is an example of a signal flow of a process in which a download processing module partially downloads data of an area changed to an embedded device using data communication through an OTA method.

Hereinafter, an operation principle of a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings and description. However, the drawings shown below and the following description are for preferred implementation methods among various methods for effectively describing the features of the present invention, and the present invention is not limited only to the following drawings and description.

In addition, in the following description of the present invention, when it is determined that detailed descriptions of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, detailed descriptions thereof will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to a user's or operator's intention or practice. Therefore, the definition should be made based on the overall contents of the present invention.

In addition, a preferred embodiment of the present invention to be carried out below is already provided in each system functional configuration to efficiently describe the technical components constituting the present invention, or a system function that is typically provided in the technical field to which the present invention pertains. The configuration is omitted as much as possible, and the functional configuration that should be additionally provided for the present invention will be mainly described.

If a person having ordinary knowledge in the technical field to which the present invention pertains, it will be possible to easily understand the functions of components already used in the prior art among the omitted functional configurations not shown below, and also the omitted components as described above The relationship between the elements and the components added for the invention will also be clearly understood.

In addition, the following examples will be used to appropriately modify the terminology so that those skilled in the art to clearly understand the technical features of the present invention to effectively understand, but the present invention is It is by no means limited.

As a result, the technical spirit of the present invention is determined by the claims, and the following examples are one means for efficiently explaining the technical spirit of the present invention to those skilled in the art to which the present invention pertains. It's just work.

First, FIG. 1 is a schematic diagram schematically showing a multi-hop wireless network system according to an exemplary embodiment of the present invention, and FIG. 2 is a block diagram schematically illustrating a channel allocation module according to an exemplary embodiment of the present invention. . As illustrated, the multi-hop network system according to the present invention has available channel information, each of which includes preferred channel information, and includes one or more nodes 100 that provide corresponding channel information when setting channel allocation, and the Internet. It is connected to the external network line, forms a mesh network with one or more nodes, and includes a central node 200 including a channel allocation module 210 that allocates channels by receiving or collecting channel information provided from one or more nodes. It is configured by.

The node 100 may be implemented as, for example, a mesh AP on a wireless mesh network, and each node 100 includes a plurality of wireless transceivers for data transmission and reception. Mesh AP forms a wireless backbone network so that data generated by terminals receiving services from the AP can be delivered to the Internet access point to receive Internet services. When the node 100 transmits available channel information including a preferred channel to the channel allocation module 210 of the central node 200 according to the request for available channel information from the central node 200, or when entering a new mesh network It provides its available channel information to the channel allocation module 210 of the central node 200. Provision of the available channel information of the node 100 to the central node 200 is provided to the central node 200 by relaying the nodes 100, and is allocated by the channel allocation module 210 of the central node 200 By receiving channel information and transmitting and receiving data to and from the neighboring node 100, Internet services are provided to terminals.

The wireless transceiver used in the node 100 according to the present invention may be implemented as a half-duplex wireless transceiver. One wireless transceiver can transmit or receive at a time through different channels with a constant delay, and there are several channels in which wireless channels do not overlap. In the IEEE 802.11a standard, 12 non-overlapping channels are allocated. At this time, it is known that the node 100 having multiple radio transceivers may cause interference when transmitting adjacent channels through different transceivers even though they are non-overlapping channels.

Therefore, since the number of non-overlapping channels that can be used simultaneously in one node 100 is limited, it is assumed in the specification of the present invention that one node 100 uses up to four channels.

Each node 100 is fixed, and one node 100 has a limited number Q (2 ≤ Q ≤ C) transceiver in a system in which there are C channels available. However, the node 100 may have different numbers of transceivers. A link is created when two nodes 100 use the same channel through a transceiver, and all links are assumed to be bidirectional links because most traffic mainly performs bidirectional communication like TCP.

The frame of the system consists of a Control Period and a Data Transmission Period. During the control period, a control message is transmitted through the basic channel. Each node 100 has a channel state for all channels by measuring a channel state through a transceiver. From this, the top k preferred channel list (PCL) having good channel status is maintained. All nodes 100 know a common basic channel set in advance, and transmit a preferred channel list (PCL) to the central node 200 that manages channel allocation through the channel.

Here, in general, in a mesh network, a node with an Internet access point becomes the central node 200, and the central node 200 allocates a channel to the interfaces of the nodes 100 from the preferred channel list (PCL) of all nodes 100. It tells the result. The basic channel is used only for the control period, and in the data transmission period, the basic channel can also be used for data transmission. During the data transmission period, data is transmitted and received with the neighboring node 100 using a channel determined by the central node 200. The frame comprising the control period and the data transmission period is repeated periodically.

In addition, the channel allocation technology of the wireless network of the present invention can operate independently of the existing routing protocol. Routing protocols such as DSR, AODV, and OLSR can be used as well as protocols such as WCETT, MCR, and AETD, which are routing protocols considering the existing multi-channel.

The central node 200 is a kind of Internet access point that is directly connected to a network line including the Internet so that terminals connected to a plurality of nodes 100 on the mesh network can receive Internet services. The central node 200 controls data transmission and reception by allocating a channel used when each node 100 transmits and receives data. The central node 200 is equipped with a channel allocation module 210 that receives or collects available channel information of each node 100 and effectively allocates and provides a channel used when transmitting / receiving data between the nodes 100.

The channel allocation module 210 is manufactured as a program and is mounted and driven in the control means of the central node 200, and receives or collects available channel information including a preferred channel from the nodes 100 on the mesh network every predetermined period or It detects the addition or removal of the node 100, receives or collects available channel information, and graphs modeling the collected available channel information to calculate an optimal channel and allocates a channel to each node 100.

The channel allocation module 210 receives channel information collection unit 211 that receives or collects available channel information including a preferred channel from node 100, and available channel information collected by channel information collection unit 211. Through a multi-graph generation unit 212 for calculating a multi-connection link between each node 100, and generating a multi-graph using the calculated connection link, through the multiple graphs generated by the multi-graph generation unit 212 A multi-channel collision graph generator 213 for generating a multi-channel collision graph by calculating a channel collision relationship due to interference of a connection link between each node 100, and a multiple generated by the multi-channel collision graph generator 213 It comprises a channel assignment unit 214 for allocating a channel to the connection link between each node 100 with reference to the channel collision graph.

The channel information collecting unit 211 collects channel information for channel allocation by receiving or receiving available channel information including a preferred channel used for data transmission and reception between nodes 100 from a plurality of nodes 100 on a mesh network. do.

The multi-graph generating unit 212 calculates the multi-connection link of the nodes 100 collected by the channel information collection unit 211, and generates and models the multi-link using the calculated connection link. The graph model generated by the multi-graph generator 212 is an extension of the connectivity graph model of the link between the existing nodes 100, but the graph model according to the present invention models a mesh network as a multi-graph Is different from

In the existing model, the connectivity graph was modeled as a simple graph. That is, the simple graph is a graph in which only one link exists between two nodes 100. On the other hand, in the present invention, the connection graph is modeled as a multi-graph that contrasts with a simple graph, which is a graph that can have two or more links between two nodes 100.

In a mesh network having such multiple transceivers, a connection graph representing a connection state is defined as Multi-graph Connectivity Graph (MGCG) G = {V, E}. Here, in MGCG, the vertex set V is composed of the nodes 100 of the mesh network, and the edge set E is composed of links between the mesh networks. In MGCG, vertex and edge refer to the node 100 and link of the mesh network, and in the present invention, they are used interchangeably in the same sense.

The description of the multiple graphs will be described in more detail with reference to FIG. 3.

3 is a schematic diagram schematically showing a multi-graph according to an exemplary embodiment of the present invention. As shown, a link is created when two nodes use the same channel for each transceiver. In addition, when two nodes allocate channels to two or more transceivers each other, multiple links are created between the two nodes. In FIG. 1, nodes 1 and 2 are nodes having 4 transceivers, respectively, and the remaining nodes 3, 4, 5, and 6 are nodes having 2 transceivers.

In this case, since nodes 1 and 2 can create two links with each other because at least one remaining transceiver is left, two links A and B can be created between nodes 1 and 2 on the graph.

The multi-channel collision graph generation unit 213 generates a multi-channel collision graph by calculating a channel collision relationship due to interference of connection links between nodes through the multiple graphs generated by the multi-graph generation unit 212.

The multi-channel collision graph generation unit 213 generates a multi-channel conflict graph (MCCG) expressing collisions between links from the multi-graph generated by the multi-graph generation unit 212. The multi-channel collision graph is defined as G '= {V', E '}, where in the multi-channel collision graph, the vertex set V' is the set where the link is a node in the MGCG, and the edge set E ' Is a set of edges connected between interfering links in MGCG.

Since interference between links assumes a bidirectional link in the mesh network, it occurs when one of the following two conditions is satisfied. First, in MGCG, link e and all e's sharing a node are defined as links causing interference. In addition, a link e 'having a node that can hear transmission from one of the two nodes of link e is defined as a link causing interference.

The multi-channel collision graph generated by the multi-channel collision graph generator 213 will be described in more detail with reference to FIG. 4.

4 is a schematic diagram schematically showing a multi-channel collision graph according to an exemplary embodiment of the present invention. As shown, link A interferes with all links. Link A is a link that satisfies the first condition and causes interference because nodes are shared through links B, D, E, and F.

In addition, link G satisfies the second condition because node 5 or 6 can receive the transmission of node 1 or 2 of link A, and link C is able to receive the transmission of node 2 of node A by node 3 Therefore, it satisfies the second condition and becomes a link causing interference. Therefore, in the multi-channel collision graph, link A has all nodes and links. Likewise, link C interferes with links A, B, D, and F, but does not interfere with links E, G.

The method of maximizing the transmission amount between each node is to allocate a channel to a node to minimize interference between channels. Accordingly, the channel allocating unit 214 allocates a channel to a connection link between nodes with reference to the multi-channel collision graph generated by the multi-channel collision graph generating unit 213. The channel allocation unit extracts a preference channel extraction unit 214-1 that determines and extracts a preferred channel from available channels for each node, and a node that uses the extracted preference channel as a common preference channel, and is extracted from a multi-channel collision graph. A sub graph generator 214-2 for generating a sub graph including only nodes, and a priority for each sub graph is assigned, and a channel is allocated to each node on the sub graph according to the given priority, but the channel is It comprises a channel assignment processing unit 214-3 that deletes the assigned node from other subgraphs and allocates a channel to the connection link between nodes.

According to a characteristic aspect of the present invention, the channel allocator 214 according to the present invention can be maximized through a method of obtaining vertex coloring in a multi-channel collision graph and allocating a channel to a link to minimize inter-channel interference. Vertex Coloring is to allocate different colors between adjacent nodes. However, such a Vertex Coloring method cannot consider different interference for each channel experienced by individual nodes.

Therefore, the List Coloring technique was applied as a method to perform vertex coloring in consideration of different channel interference experienced by each node. In this list coloring, a color that is different from the color of an adjacent node is allocated from a color list preferred by a node. List Coloring can be defined as follows.

Coloring R of graph G = {V, E} is defined as a function f: V → C that satisfies f (v) ≠ f (w) for nodes v and w adjacent to each other for a given color set C. In addition, when all nodes v∈V in the graph G = {V, E} have a color list L (v) ⊆C, Coloring R satisfying f (v) ∈L (v) for all nodes v∈V If it exists, it is defined that list coloring is possible.

First, a known heuristic algorithm is the k-GL (Greed List) algorithm. This algorithm works by assigning colors one by one while selecting nodes. First, random nodes v are randomly selected from the nodes having the smallest color list | L (v) |. Color c is randomly selected from L (v) and assigned to node v. For node v assigned color c, all nodes u adjacent to v are updated by removing color c from L (u). At this time, if the selected L (v) is 0, the algorithm fails. In addition, the k-GL algorithm is simple, but since colors are randomly selected, there is a problem in that colors cannot be allocated in consideration of the relationship between nodes.

In the present invention, a new sub-graph list coloring algorithm is proposed. For each color i, sub graph Gi = {V _i , E _i } is generated. That is, node set V _i is a set of all nodes v that satisfy color i i L (v), and E _i is a link (u, v) ∈ E for all two node pairs (u, v) belonging to E _i It is a set made of links (u, v) satisfying. For each subgraph, the node generates an ordered set N _i from nodes with a lower degree in graph G _i . For colors i to N _i with the smallest | N _i |, color i is assigned to all nodes that are not connected in graph G _i . Here, the node of the same order selects the node of the higher order from the original graph G. All nodes assigned color i are removed from the other graph G _j (j ≠ i). This process is repeated for all subgraphs G _i . The SLC (Sub-graph List Coloring) algorithm described above is the same as Algorithm 1.

[Algorithm 1]

In the List Coloring algorithm, the k value is an important element of the algorithm. When the maximum degree of any graph G is Δ (G), list coloring is possible when Equation 1 is satisfied.

In the present invention, since it is assumed that there are m transceivers, the maximum degree on the multi-channel collision graph is limited to 2 (m-1) 2. If m is 4, if k is 6, you can get the list coloring result.

The channel allocation unit 214 using such a list coloring technique will be described in detail with reference to FIGS. 5 and 6. 5 is a schematic diagram schematically showing a multi-channel collision graph and sub-graphs according to one preferred embodiment of the present invention. As shown, a multi-channel collision graph consisting of 5 (A, B, C, D, E) nodes and 3 {1, 2, 3} available channels, for example, prefers channel 1 in common. The nodes are C and E, and the nodes C and E form a subgraph G1. In addition, nodes that commonly prefer channel 2 are A, D, and E, and nodes A, D, and E form a subgraph G2. Finally, the nodes that commonly prefer channel 3 are A, B, C, and D, and nodes A, B, C, and D form a subgraph G3.

The three sub-graphs formed in this way are dynamically changed according to | Gi |, which changes with each traverse of the sub-graphs. Accordingly, the priority of the above-described three sub-graphs is in order of G1, G2, and G3.

In addition, there are the same number of connection links on the sub graph, and when two nodes are connected, a channel having more connection links is selected on the multi-channel collision graph G to allocate channels preferentially to the connection links of the corresponding nodes.

Looking at the subgraph G1, since the preferred channel of node C and node D is 1 in common, channel 1 should be colored to one of the two nodes. Select the node. In the specification of the present invention, the color corresponding to channel 1 is colored in node E.

When channel 1 is colored in node E, channels are allocated in the state in which the node E to which the channel is already allocated is deleted in the remaining subgraphs G2 and G3. When the node E is deleted from the subgraph G2, the node A and the node D do not interfere because the link is not connected. Therefore, the channel 2, which is a common preferred channel, is colored in node A and node D.

If channel 2 is colored in node A and node D, if node E, node A, and node D are deleted from the remaining subgraph G3, nodes B and C remain. Node B has only one preferred channel, and Node C has preferred channels 1 and 3, but channel 1 is already assigned to node E, which causes interference, so channel 3 is colored to both nodes.

The channels allocated for each node by the SLC (Sub-graph List Coloring) algorithm and the channels allocated for each node by the k-GL algorithm are shown in FIG. 6. 6 is a schematic diagram schematically showing channel allocation results for each node by a sub-graph list coloring (SLC) algorithm according to an exemplary embodiment of the present invention and channel allocation results for each node by a k-GL algorithm.

As illustrated, when a channel is allocated for each node by a sub-graph list coloring (SLC) algorithm according to the present invention, the channel causing interference is a node 2 by node k-GL compared to node 2 between node B and node C. When allocating a channel per channel, the channel causing interference is two such as channel 3 between node A and node B and 2 between node D and node E. Therefore, the amount of transmission between each node is the SLC (Sub-graph List Coloring) algorithm. It may fall compared to.

The channel allocating unit 214 propagates channels allocated for each node to each node by a sub-graph list coloring (SLC) algorithm, and each node is propagated to all nodes in the mesh by relaying.

Hereinafter, a channel allocation process on the multi-hop wireless network system according to the present invention will be described.

7 is a flowchart schematically illustrating a channel allocation process of a wireless network according to an exemplary embodiment of the present invention. As illustrated, a method for allocating a wireless network channel according to the present invention includes an information collection step of receiving or collecting node information including available channel information of each node on a wireless network, and a link link between each node through the collected node information. The connection relationship calculation step of calculating the multi-connection relationship of the, and the collision relationship calculation step of calculating the channel collision relationship by the interference of the connection link between each node according to the calculated multi-connection relationship, and the collision relationship calculated by the collision relationship calculation step It comprises a channel allocation step of allocating a channel to the connection link between each node, and providing a channel allocated to each link to each node.

According to a characteristic aspect of the present invention, the channel allocation step according to the present invention includes determining and extracting a preferred channel from available channels for each node, extracting a node using the corresponding channel as a common preferred channel for all channels, and multiplexing Generating a subgraph including only nodes extracted from the channel collision graph, assigning priorities for each subgraph, and assigning channels to each node on the subgraph according to the given priority, but the channel is It consists of deleting the assigned node from other sub-graphs and assigning a channel to the connection link between the nodes.

When a mesh network is newly formed or a node is added or deleted on an existing mesh network, the central node 200 directly connected to a network connection line including the Internet is available including a preferred channel to each node on the mesh network. Request channel information.

When an available channel information request is propagated from the central node 200, each node on the mesh network propagates it to nodes capable of transmitting and receiving nearby data according to a relay function between nodes, thereby requesting available channel information to all nodes on the mesh network. To propagate. Nodes that have received a request for available channel information from the central node 200 each transmits available channel information including their favorite channels to the central node 200, at this time also through the inter-node relay function, the central node 200 It will be collected as (S101).

The multi-connection link between nodes is calculated through the available channel information for each collected node of the channel allocation module 210 of the central node 200, and the calculated connection link is used to generate and model a multi-graph. The multiple graph is a graph capable of having two or more links between two nodes (S103).

When a multi-graph is generated, the multi-channel collision graph generator 213 calculates a channel collision relationship due to interference of a connection link between nodes through the multi-graph to generate a multi-channel collision graph (S105). The multi-channel collision graph is defined as G '= {V', E '}, where in the multi-channel collision graph, the vertex set V' is the set where the link is a node in the MGCG, and the edge set E ' Is a set of edges connected between interfering links in MGCG.

Since interference between links assumes a bidirectional link in the mesh network, it occurs when one of the following two conditions is satisfied. First, in MGCG, link e and all e's sharing a node are defined as links causing interference. In addition, link e 'having a node that can hear transmission from one of the two nodes of link e is defined as a link causing interference.

When a multi-channel collision graph is generated, the channel allocator 214 extracts a preferred channel for each node by referring to the multi-channel collision graph generated by the multi-channel collision graph generator 213 (S107), and SLC (Sub-graph) List Coloring) generates a sub-graph through an algorithm (S109).

The SLC (Sub-graph List Coloring) algorithm of the channel allocating unit 214 will be described with reference to FIG. 5, which includes five nodes (A, B, C, D, E) and three {1, 2, 3} nodes. For a multi-channel collision graph composed of available channels, for example, nodes that commonly prefer channel 1 are C and E, and nodes C and E form subgraph G1. In addition, nodes that commonly prefer channel 2 are A, D, and E, and nodes A, D, and E form a subgraph G2. Finally, the nodes that commonly prefer channel 3 are A, B, C, and D, and nodes A, B, C, and D form a subgraph G3.

Among the three sub-graphs formed in this way, priority is given in the order of the small number of nodes.

In addition, there are the same number of connection links on the sub graph, and when two nodes are connected, a channel with more connection links is selected on the multi-channel collision graph G to preferentially allocate a channel to the connection link of the node.

Looking at the subgraph G1, since the preferred channel of node C and node D is 1 in common, channel 1 should be colored to one of the two nodes. Select the node. In the specification of the present invention, the color corresponding to channel 1 is colored in node E.

When channel 1 is colored in node E, the channel is allocated with node E deleted in the remaining subgraphs. When the node E is deleted from the subgraph G2, the node A and the node D do not interfere because the link is not connected. Therefore, the channel 2, which is a common preferred channel, is colored in node A and node D.

If channel 2 is colored in node A and node D, if nodes A and D are deleted from the remaining subgraph G3, nodes B and C remain. Node B has only one preferred channel, and Node C has preferred channels 1 and 3, but channel 1 is already assigned to node E, which causes interference, so channel 3 is colored to both nodes.

The channel allocating unit 214 propagates the channels allocated for each node to each node by the sub-graph list coloring (SLC) algorithm, and each node propagates to all nodes in the mesh by relaying (S111), (S113).

7 and 9, a partial download processing process between the download processing module 120 and the embedded device 20 of the partial update service system of the software embedded in the embedded device according to the present invention will be described in more detail.

When the customer knows that the software has been changed and visits a sales office such as a customer support center and requests a software upgrade of the embedded device possessed by the customer, the sales office manager connects the embedded device 20 to the sales office terminal 10b. The download processing module 120 is executed in a state in which data communication is possible between the office terminal 10b and the embedded device 20.

First, the download processing module 120 executable in the office terminal 10b loads the identification key file for each area from the embedded device 20 through the process of FIG. 7.

7 shows a signal flow of a process in which a download processing module loads a file storing an identification key for each area from an embedded device using data communication.

As shown in the figure, the download processing module 120 transmits request information (AT $ DNINFO) to transmit a file storing an identification key for each area of software to be partially downloaded to the embedded device 20.

Then, the embedded device 20 receiving this analyzes the header of the file storing the identification key for each area stored therein, and transmits information for transferring the file storing the identification key for each area (szAABBBB), that is, identification for each area The total size (BBBB) of the file storing the key is transmitted to the download processing module 120 as to how much to transmit the file storing the identification key for each area in packet unit (AA).

When the download processing module 120 receiving the transmission information (szAABBBB) from the embedded device 20 transmits a signal confirming (OK) the transmission as response information to the embedded device 20, the download processing module 120 receives it. An embedded device 20 transmits the file storing the identification key for each area in the above-described transmission packet unit (AA) to the office terminal 10b.

When all packet amounts corresponding to the total size (BBBB) of the file storing the identification key for each area are transmitted, response information (Response) confirming (OK) the completion of transmission to the embedded device 20 by the download processing module 120 ) send.

In this way, the download processing module 120 receiving the file storing the identification key for each area to be downloaded in the embedded device 20 stores the identification key for each area of the software to be downloaded in the branch terminal 10b. The changed part is searched by comparing the file and the file received from the embedded device 20. Since the search for this changed part has been described in detail above, a duplicate description thereof will be omitted.

When there is a changed part for the corresponding software, only the data of the area changed to the embedded device 20 through the download processing module 120 is selectively transmitted through the process shown in FIG. 9 to update the software stored in the embedded device.

If, on the contrary, the embedded device loads the file storing the identification key for each area from the download processing module using data communication, the signal flow shown in FIG. 7 may be reversed.

9 shows a signal flow of a process in which the download processing module partially downloads data of a changed area to an embedded device using data communication.

First, the download processing module 120 reads data of a certain size among the data of the changed area of the software to be partially downloaded stored in the office terminal 10b, and uploads it to a specific address of the RAM of the embedded device 20 It is included in the command to request (CMD_RAM) to transmit to the embedded device 20.

The embedded device 20 stores the data of the predetermined size in a specific address of the RAM of the embedded device 20 according to the transmitted command (CMD_RAM), and responds to it with the download processing module 120 ) Send information.

On the other hand, as shown in Figure 8 and 10, the download processing module 120 is mounted on a server (not shown in the figure) interlocked with the mobile communication system of the software to be partially downloaded using the data communication service of the mobile communication system The identification key for each area and the data of the changed area to be partially downloaded may be implemented by an over the air (OTA) method that transmits data to the embedded device 20.

8 and 10 are diagrams illustrating data flow between a base station (BS) and an embedded device.

In this case, unlike the case where the download processing module 120 is mounted on the sales office terminal 10b, it is possible to provide a partial update service of the software embedded in the embedded device through the mobile communication network, so that the customer does not need to visit the sales office. have.

The embodiment shown in FIGS. 8 and 10 differs only from the embodiment shown in FIGS. 7 and 9 only in the location and communication method of the terminal on which the download processing module 120 is mounted. Since it is the same as the embodiment shown in FIGS. 7 and 9, duplicate description will be omitted.

Claims (5)

An information collection step of receiving or collecting node information including available channel information of each node on the wireless network;
A connection relationship calculation step of calculating a multi-connection relationship of connection links between nodes through the collected node information;
A collision relationship calculating step of calculating a channel collision relationship due to interference of a connection link between nodes according to the calculated multi-connection relationship;
A channel allocation step of allocating a channel to a connection link between nodes with reference to the collision relationship by the collision relationship calculation step;
Providing a channel allocated to each link to each node;
Comparing old version software information with new version software information;
Determining different parts of the old version and the new version software;
And recording a new version part for the different parts in a corresponding area of the old version software. The method of claim 1,
The old version and the new version of the software are made up of several areas, and each area is assigned an identification key, and the channel allocation method of the network is characterized by determining different parts of the old version and the new version by comparing the identification keys. . The method of claim 1,
The determination of the different parts of the old version and the new version is performed by comparing the respective version information. The method of claim 1,
The above information collection steps:
Channel allocation method of the network, characterized in that received or collected through the relay between each node. The method of claim 1,
The connection relationship calculation step is:
A channel allocation method in a network, characterized by generating multiple graphs having multiple channels for multiple transmission and reception between nodes.

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