KR101866685B1 - Method and system for topology controlled channel assignment with power control in wireless mesh network - Google Patents

Abstract

A power control and channel allocation method and system for topology control of a wireless mesh network are disclosed. The power control and channel allocation method and system for topology control of a wireless mesh network according to an embodiment of the present invention include configuring a wireless mesh network topology based on transmitting and receiving powers between neighboring nodes measured using beacon packets and allocating channels based on a signal to interference plus noise ratio (SINR) thereby reducing energy consumption of mesh nodes forming a wireless mesh network. In a power control and channel allocation method in a wireless mesh network, the method may comprise the steps of measuring transmission and reception powers of a neighboring node with respect to a plurality of mesh nodes included in the wireless mesh network; generating a topology graph, GT corresponding to the wireless mesh network that indicates a plurality of mesh nodes and link information between the plurality of mesh nodes based on the measured transmission and reception powers; and allocating channels corresponding to each of the plurality of mesh nodes based on the generated topology graph and a signal to interference plus noise ratio (SINR).

Description

[0001] METHOD AND SYSTEM FOR POWER CONTROL AND CHANNEL ALLOCATION FOR POWER CONTROL IN WIRELESS MESH NETWORK [0002] FIELD OF THE INVENTION [0003]

The following discussion relates to techniques for controlling the power of mesh nodes forming a wireless mesh network and assigning channels to each of the mesh nodes.

The Wireless Mesh Network (WMN) covers a wide range of areas because of its ease of deployment, efficient maintenance, scalability and connectivity. The wireless mesh network can be used in places where it is difficult to install a wired network or in an area where an immediate network construction is required. For example, it can be used in wireless access networks, areas where a network has been destroyed by a disaster or a disaster, and areas where additional networking is required due to increased traffic.

Thus, the wireless mesh network can be used in a region where a network is destroyed due to a disaster, or in an area where additional network construction is required due to an increase in traffic, so that a wireless mesh node such as a router can reliably supply power Getting supplies is not easy. Accordingly, in establishing the wireless mesh network, it is very important to reduce the power consumption of the wireless mesh node such as a router. For example, according to the Friis's Formula, the received power is proportional to the transmit power and inversely proportional to the square of the distance. Also, using large transmission power to connect to distant neighbors causes performance degradation of network due to power outage at limited power, so reducing power consumption of wireless mesh nodes is a very important factor when constructing WMN.

And, increasing the transmission power to maintain the connection between wireless mesh nodes increases interchannel interference. Accordingly, it is necessary to improve the network capacity and effectively use the channel by controlling an appropriate transmission power. Non-Patent Document [1] Marina , Mahesh K., Samir R. Das , and Anand Prabhu Subramanian. "A topology control approach for multiple channels in multi-radio wireless mesh networks." Computer networks 54.2 (2010): 241-256. Is a greedy heuristic centralized channel allocation scheme, CLICA, which uses a protocol interference model to guarantee network connectivity and minimize the maximum interference, but does not consider power consumption , There is a difficulty in applying the physical interference model considering the actual environment to the actual communication environment.

Korean Patent No. 10-1018141 is directed to a system and method for performing topology control in a wireless mesh network. The system calculates a link cost and determines transmission power adjustment and routing based on the calculated link cost. And a topology control in an ad-hoc network environment, which is a relay network environment, rather than a wireless mesh network environment, is proposed.

[1] Marina, Mahesh K., Samir R. Das, and Anand Prabhu Subramanian. "A topology control approach for multiple channels in multi-radio wireless mesh networks." Computer networks 54.2 (2010): 241-256.

A power control and channel allocation method and system for controlling topology of a wireless mesh network according to an exemplary embodiment of the present invention includes configuring a wireless mesh network topology based on transmission / reception power between neighboring nodes measured using beacon packets, So as to save energy consumption of the mesh nodes forming the wireless mesh network.

In addition, in order to distribute traffic by creating multipath by ensuring the connectivity of the gateway (GW) mesh node according to the Hybrid Wireless Mesh Protocol (HWMP), which is a standardized routing protocol in the topology configuration.

In addition, by preventing unnecessary link generation based on the SINR, inter-channel interference is reduced, and in the case of a mesh node with low connectivity, transmission power is increased to secure connectivity, thereby increasing throughput of the entire network, In order to reduce the delay time.

A method for power control and channel allocation in a wireless mesh network, the method comprising: measuring transmission and reception power of a neighboring node for a plurality of mesh nodes included in the wireless mesh network; And generating a topology graph G _T corresponding to the wireless mesh network indicating link information between a plurality of mesh nodes and mesh nodes based on the received power and generating a topology graph G _{T corresponding} to the generated topology graph and SINR to Interference plus Noise Ratio (MIMO) to allocate a channel corresponding to each of the plurality of mesh nodes.

According to an aspect of the present invention, the measuring step includes broadcasting a beacon packet at a predetermined transmission power for each predefined beacon period, calculating a reception power when receiving an acknowledgment (ACK) packet as a response to the beacon packet, And matching the transmission power and the reception power with an identifier of a corresponding mesh node to which the confirmation packet has been transmitted.

According to another aspect, the measuring step includes the steps of: updating the number of neighborable nodes connectable to the transmission power currently set in the beacon period based on the acknowledgment (ACK) packet; and updating the number of neighboring nodes And increasing the transmission power by one level until it becomes equal to the number of interfaces.

According to another aspect, the measured received power and the transmit power when receiving the beacon packet may be stored in the neighboring node that received the beacon packet, by matching with the identifier of the mesh node that transmitted the beacon packet.

According to another aspect of the present invention, the step of allocating the channel includes a step of increasing the transmission power and performing the connectivity enhancement so as to be connected to another neighbor node when the neighboring node is currently connected among the plurality of mesh nodes .

According to another aspect of the present invention, the traffic may be distributed as the multipath is generated as the neighboring node is connected to the other neighbor through the connection enhancement.

According to another aspect of the present invention, in the step of allocating the channel, when a triangle topology in which three neighboring mesh nodes are connected in a triangle shape is generated for the plurality of mesh nodes, And selecting one of the links corresponding to two neighboring nodes based on the SINR corresponding to two neighboring nodes connected based on any one of the nodes.

According to another aspect of the present invention, the step of allocating the channel includes: allocating channel allocation to a gateway node, a non-edge node, and an edge node, which are connected to an external network among the plurality of mesh nodes, And performing the steps of:

According to another aspect of the present invention, the step of allocating the channel includes calculating SINR of a channel corresponding to each neighboring node with respect to neighboring nodes capable of receiving a beacon packet, Comprising the steps of: generating a channel matrix, distributing the generated channel matrix to the plurality of mesh nodes via a common channel, and determining a predetermined specific time based on the distributed channel matrix And performing channel allocation on the channel.

1. A power control and channel allocation system in a wire mesh network, comprising: a measurement unit for measuring transmission and reception powers of a plurality of mesh nodes included in the wireless mesh network, A topology graph generator for generating a topology graph G _T corresponding to the wireless mesh network indicating link information between a plurality of mesh nodes and mesh nodes based on transmission and reception powers, And a channel allocation unit allocating a channel corresponding to each of the plurality of mesh nodes based on SINR (Signal to Interference plus Noise Ratio).

According to an aspect of the present invention, the measurement unit broadcasts a beacon packet at a predetermined transmission power for each predefined beacon period, measures reception power when receiving an acknowledgment (ACK) packet as a response to the beacon packet, The transmission power and the reception power may be matched with the identifier of the mesh node that transmitted the confirmation packet and stored.

According to another aspect of the present invention, the measurement unit updates the number of neighbor nodes connectable to the transmission power currently set in the beacon period based on the acknowledgment (ACK) packet, and updates the number of the updated neighbor nodes to the number of interfaces The transmission power can be increased by one step until it becomes the same.

According to another aspect, the measured received power and the transmit power when receiving the beacon packet may be stored in the neighboring node that received the beacon packet, by matching with the identifier of the mesh node that transmitted the beacon packet.

According to another aspect of the present invention, the channel allocation unit may increase the transmission power and perform the connection enhancement so as to be connected to another neighbor node when the current neighbor node among the plurality of mesh nodes is one.

According to another aspect of the present invention, the traffic may be distributed as the multipath is generated as the neighboring node is connected to the other neighbor through the connection enhancement.

According to another aspect of the present invention, when a triangle topology in which three neighboring mesh nodes are connected in a triangle shape to the plurality of mesh nodes is generated, It is possible to select any one of the links corresponding to two neighboring nodes based on the SINR corresponding to two neighboring nodes connected based on one node.

According to another aspect of the present invention, the channel allocator performs channel allocation in the order of a gateway (GW) node, a non-edge node, and an edge node connected to an external network among the plurality of mesh nodes .

According to another aspect of the present invention, the channel allocator calculates the SINR of a channel corresponding to each of the neighboring nodes with respect to neighboring nodes capable of receiving the beacon packet, and calculates a channel matrix And distributing the generated channel matrix to the plurality of mesh nodes through a common channel and performing channel allocation at a predetermined specific time based on the distributed channel matrix. have.

A power control and channel allocation method and system for controlling topology of a wireless mesh network according to an exemplary embodiment of the present invention includes configuring a wireless mesh network topology based on transmission / reception power between neighboring nodes measured using beacon packets, The energy consumption of the mesh nodes forming the wireless mesh network can be saved.

In addition, according to the Hybrid Wireless Mesh Protocol (HWMP), which is a standardized routing protocol in the topology configuration, the connectivity of the gateway (GW) mesh node is ensured, and the traffic can be distributed by generating the multipath.

In addition, by preventing unnecessary link generation based on the SINR, inter-channel interference is reduced, and in the case of a mesh node with low connectivity, transmission power is increased to secure connectivity, thereby increasing throughput of the entire network, Can be reduced.

Figure 1 is a diagram illustrating a plurality of mesh nodes in one embodiment of the present invention.
2 is a flowchart illustrating a power control and channel allocation method for topology control according to an exemplary embodiment of the present invention.
3 is a block diagram illustrating an internal configuration of a power control and channel allocation system in an embodiment of the present invention.
4 is a flowchart illustrating an operation of measuring topology by measuring transmission and reception power in an embodiment of the present invention.
5 is a flowchart illustrating an operation of topology control and channel allocation in an embodiment of the present invention.
Figure 6 is a diagram provided to illustrate connectivity enhancement operations in one embodiment of the present invention.
Figure 7 is a diagram provided to illustrate a process for preventing triangle topology generation in one embodiment of the present invention.
FIG. 8 is a diagram illustrating a result of performing topology control and channel allocation based on transmission and reception power measurements in an embodiment of the present invention.
FIG. 9 is a graph showing performance analysis results of throughput and E2E delay time in an embodiment of the present invention.
10 is a graph comparing the throughputs of the HWMP proactive mode and the reactive mode.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

The embodiments relate to power control and channel allocation for topology configuration in a wireless mesh network (WMN), in particular, to measure receive power and transmit power using beacon packets, To a technique for allocating channels based on the SINR (Signal to Interference plus Noise Ratio) of each channel link, by constructing a network topology based on reception and transmission power.

In this embodiment, the plurality of mesh nodes forming the wireless mesh network include a general mesh node corresponding to a mesh router, and a mesh node (GW node) corresponding to a gateway connected to an external network can do. In addition, general mesh nodes can be classified into an edge node and a non-edge node.

In the present embodiment, an edge node represents an end node (or end node) of a wireless sensor network, and a non-edge node represents a node of a plurality of mesh nodes forming a wireless mesh network. And all the remaining nodes except for the mesh node and the edge node corresponding to the edge node. For example, an edge node may represent a node disposed or installed in a building, a place, or the like in order to perform fire detection, earthquake detection, temperature change detection, wind speed detection, vibration detection, and the like in a wireless sensor network.

In the present embodiments, when a neighboring node transmits a beacon packet from a specific mesh node (e.g., a GW node, a non-edge node, or an edge node) included in the wireless mesh network, the neighbor node can indicate a mesh node capable of receiving the transmitted beacon packet have.

In the present embodiments, the 'power control and channel allocation system' may represent a GW node with a gateway function and may represent a general mesh node, that is, an edge node or a non-edge node .

In the present exemplary embodiments, transmission / reception power measurement, topology control, and channel allocation are performed using a beacon packet in a GW node. However, this is an embodiment, and the beacon packet transmission and beacon packet transmission The reception power measurement operation when receiving the transmission power and the beacon packet can be performed in all the mesh nodes. Then, an operation of performing topology control (i.e., controlling transmission power) and allocating a channel (i.e., TCCA algorithm operation) based on the measured transmission and reception powers can be performed at the GW node.

Further, terms used for power control and channel allocation for topology control in the present embodiments can be defined as shown in Table 1 below.

Figure 1 is a diagram illustrating a plurality of mesh nodes in one embodiment of the present invention.

1, a mesh node (GW node) 101 corresponding to a gateway may be connected to an external network such as the Internet 110, and the remaining mesh nodes (e.g., edge nodes and non-edge nodes) And may be connected to the Internet 110 through the node 101. [

Among the plurality of mesh nodes, the remaining mesh nodes other than the GW node 101 may be classified into an edge node and a non-edge node. Here, an edge node represents an end (or end) node of a wireless sensor network, and a non-edge node 102 represents an edge node and a GW node 101 of the entire mesh nodes . For example, an edge node may represent a node disposed or installed in a building, a place, or the like in order to perform fire detection, earthquake detection, temperature change detection, wind speed detection, vibration detection, and the like in a wireless sensor network.

FIG. 2 is a flowchart illustrating a power control and channel allocation method for topology control according to an exemplary embodiment of the present invention. FIG. 3 is a flowchart illustrating a power control and channel allocation method according to an exemplary embodiment of the present invention. Fig.

The power control and channel allocation system 300 of FIG. 3 may include a measurement unit 310, a topology graph generation unit 320, and a channel allocation unit 330. 2 may be performed by the measuring unit 310, the topology graph generating unit 320, and the channel assigning unit 330, which are components of FIG. 2, the operation of the measurement unit 310 may be performed in addition to all the mesh nodes, that is, the GW node, the edge node 300, And non-edge nodes.

In step 210, the measurement unit 310 may generate (i.e., acquire) the wireless mesh network graph G based on a given wireless mesh network topology.

와

간의 링크 집합을 포함할 수 있다.The wireless mesh network graph G = (V, E) may include a set V of mesh nodes and a link set E between mesh nodes. For example,

Wow

Lt; / RTI > link set.

In step 220, the measurement unit 310 may measure transmission power or reception power of neighboring nodes according to the wireless mesh network topology given in advance.

For example, the measuring unit 310 may measure a transmission power when transmitting a beacon packet to neighboring nodes, and may compare the measured transmission power with an identifier (e.g., a node ID) of neighboring nodes Stored and maintained. At this time, when the power control and channel allocation system 300 is in the position of receiving the beacon packet, the measuring unit 310 can measure the reception power when receiving the beacon packet, (E.g., node ID) of the transmitted node.

In operation 230, the topology graph generator 320 may generate a transmission power controlled topology graph G _T = (V, E _T ) based on a Topology Controlled Channel Assignment (TCCA) algorithm. Here, the operation of generating the topology graph for controlling the transmission power can be performed based on a distributed scheme. The detailed operation for measuring and controlling the transmission power or the reception power will be described later with reference to FIG. 4 below.

In step 240, the channel allocation unit 330 may generate a channel allocation graph G _CA = (V, E _CA ) for allocating the channel with the best SINR according to the generated topology graph G _T. Here, the operation of generating the channel allocation graph for allocating the channel can be performed based on the centralized method. The detailed operation of controlling the transmission power and allocating the channel will be described in detail with reference to FIG. 5 below.

4 is a flowchart illustrating an operation of measuring topology by measuring transmission and reception power in an embodiment of the present invention.

In FIG. 4, the steps 410 to 412 and 416 to 419 may be performed by the measuring unit 310 of FIG.

The power control and channel allocation system 401 may represent a mesh node operating on the basis of a transmission node transmitting beacon packets among the mesh nodes forming the wireless mesh network. The case where this GW node operates as a transmission node will be described as an example. This corresponds to the embodiment, and the GW node may operate as a receiving node. The mesh node 402 may represent a mesh node operating in the presence of a receiving node that receives a beacon packet among mesh nodes forming a wireless mesh network. In FIG. 4, an edge node or a non-edge node operates as a receiving node However, this corresponds to the embodiment, and the GW node may operate as the receiving node.

In FIG. 4, v _t may denote a mesh node (i.e., a transmitting node) operating as a transmitting node, and v _r may denote a mesh node (i.e., a receiving node) operating as a receiving node.

In step 410, the power control and channel allocation system 401 performs node initialization (k = 1, i = 0) and sets all interfaces to a common channel so that all mesh nodes transmit / As shown in FIG. Here, i can represent the number of neighbor nodes connectable with the current transmission power.

In step 411, power control and channel allocation system 401 may initialize the transmission power to the TxP _k.

In step 412, the power control and channel assignment system 401 may transmit beacon packets to neighboring nodes (i.e., mesh nodes) at a predefined beacon transmission time.

For example, the power control and channel allocation system 401 may transmit a beacon packet per predefined beacon period and may transmit a predefined transmit power at a beacon transmission time corresponding to the current beacon period (e.g., ) To the neighboring nodes.

에 저장할 수 있다.In step 413, the beacon packet may be received from at least one mesh node (hereinafter, referred to as 'neighbor node' 402) of a plurality of mesh nodes. When the beacon packet is received from the neighbor node 402 413: YES), in step 414, the neighbor node 402 determines the reception power when receiving the beacon packet and the transmission power when the beacon packet is transmitted from the power control and channel allocation system 401

Lt; / RTI >

에 저장 및 유지할 수 있다. 이때, 해당 GW 노드의 ID에 이미 저장된 송신 파워 및 수신 파워가 존재하는 경우, 이웃 노드(402)는 측정된 수신 파워와 상기 송신 파워로 테이블

를 갱신할 수 있다.For example, the neighbor node 402 may measure the received power when receiving the beacon packet. The received power and the transmission power when the beacon packet is transmitted at the beacon transmission time and the identifier of the channel assignment system 401 (for example, the ID of the GW node) that transmitted the beacon packet are matched with the received power,

Lt; / RTI > At this time, if the transmission power and the reception power already stored in the ID of the GW node exist, the neighboring node 402 transmits the measured reception power and the transmission power

Can be updated.

In step 415, the neighbor node 402 may send a beacon acknowledgment packet to the power control and channel assignment system 401 based on the measured received power and a predefined reference power P _ed .

For example, the neighbor node 402 compares the measured received power with the reference power P _ed , and if the received power is greater than the reference power P _ed as a result of the comparison, (ACK) packets to the power control and channel assignment system 401. [ If the received power is not greater than the reference power P _ed , the neighboring node 402 may not transmit the acknowledgment packet to the power control and channel allocation system 401.

에 저장할 수 있다. In step 416, the power control and channel assignment system 401 may receive an acknowledgment (ACK) packet from the neighboring node 402. The received power of the acknowledgment (ACK) packet and the beacon packet transmitted in the beacon period (i.e., the beacon packet corresponding to the acknowledgment packet) The transmission power of the

Lt; / RTI >

에 저장 및 유지할 수 있다. 이때, 해당 노드와 관련하여 테이블

에 이미 저장된 송신 파워 및 수신 파워가 존재하는 경우, 전력 제어 및 채널 할당 시스템(401)은 이웃 노드(402)의 식별자에 해당하는 이미 저장된 수신 파워와 송신 파워를 상기 측정된 수신 파워와 송신 파워로 테이블

를 갱신할 수 있다.For example, the power control and channel allocation system 401 matches the reception power of the acknowledgment packet and the transmission power with the identifier (e.g., node ID) of the node that transmitted the acknowledgment packet,

Lt; / RTI > At this time, the table

The power control and channel allocation system 401 determines the already received received power and transmit power corresponding to the identifier of the neighbor node 402 to the measured received power and transmit power table

Can be updated.

를 갱신한 이후, 전력 제어 및 채널 할당 시스템(401)은 연결 가능한 이웃 노드의 개수 i를 갱신할 수 있다.In step 417,

The power control and channel assignment system 401 may update the number i of connectable neighbor nodes.

가 갱신될 때마다 연결 가능한 이웃 노드의 개수 역시 한 개씩 증가하도록 갱신될 수 있다.For example, the channel assignment system 401 may increase the number i of connectable neighbor nodes by one. As such, when a confirmation packet is received

The number of connectable neighboring nodes may be updated to increase by one.

In step 418, the channel assignment system 401 can check whether the number i of renewable neighborable nodes is greater than the number K of interfaces.

If it is determined in step 419 that it is not large, the channel allocation system 401 may increase the level of the transmission power by one level.

For example, if the updated number i of connectable neighbor nodes is not greater than the number K of interfaces, the channel assignment system 401 may increase the level of the transmit power initialized in step 411 by one step (k = k + 1). If the number i of connectable neighbor nodes is greater than the number K of interfaces (i> | K |), the current level can be maintained without increasing the transmission power by one level.

시키면서, 412 내지 419 단계에 해당하는 동작(즉, 비콘 패킷 전송, 확인 패킷 수신하여 수신 파워 측정 및 송신 파워의 레벨 증가 등의 일련의 과정)을 반복 수행할 수 있다. 그러면, 토폴로지 그래프 생성부(320)는 연결 가능한 이웃 노드의 개수 i가 인터페이스의 개수 |K|와 같아질 때까지 송시 파워 레벨을 증가시키는 동작을 통해 제어된 송신 파워에 기초하여 토폴로지 그래프 G_T를 생성할 수 있다.As such, the channel assignment system 401 increases the transmit power level by one step until the number i of connectable neighbor nodes equals the number of interfaces < RTI ID = 0.0 >

(I.e., a series of processes such as beacon packet transmission, reception of an acknowledgment packet, measurement of received power, and increase of the level of transmission power) in steps 412 to 419. [ Then, the topology graph generator 320 generates a topology graph G _T based on the transmission power controlled through the operation of increasing the transmission power level until the number i of connectable neighbor nodes becomes equal to the number of interfaces | K | Can be generated.

5 is a flowchart illustrating an operation of topology control and channel allocation in an embodiment of the present invention.

(전송 노드 및 수신 노드 측의 테이블 포함)에 기초하여 토폴로지를 구성 및 제어하고, SINR에 기초하여 간섭이 최소화되도록 채널을 할당하는 동작(즉, 도 2의 230 및 240 단계에 해당하는 토폴로지 제어 및 채널 할당하는 동작)을 상세히 설명하고자 한다. In FIG. 5, a table configured based on the transmission and reception powers measured according to the TCCA algorithm

(I. E., Topology control corresponding to steps 230 and 240 of FIG. 2) and to allocate channels to minimize interference based on the SINR Channel assignment) will be described in detail.

5, steps 510 to 590 may be performed by the topology graph generator 320 and the channel allocator 330 of FIG. In FIG. 5, topology control and channel assignment may be performed at the GW node, and the power control and channel assignment system 300 may represent the GW node.

및 토폴로지 인접 매트릭스(Topology adjacency matrix)

가 초기화될 수 있다.In step 510, for the topology control and channel assignment, a channel assignment matrix

And a topology adjacency matrix.

Can be initialized.

(전송 노드 및 수신 노드 측의 테이블 포함)을 모든 메쉬 노드들(즉, 에지 노드 및 비에지 노드)로부터 수집할 수 있다.In step 520, the topology graph generator 320 generates a topology graph including a table including transmission power and reception power measured and updated for each beacon period,

(Including the transmitting node and the receiving node side tables) from all mesh nodes (i.e., edge nodes and non-edge nodes).

에 기초하여 송신 파워가 제어된 토폴로지 그래프 G_T를 생성할 수 있다.In step 530, the topology graph generator 320 generates a topology graph

To generate a topology graph G _T in which the transmission power is controlled.

), 토폴로지 그래프 G_T를 생성할 수 있다. For example, when the number j of receivable neighbor nodes (i.e., neighboring mesh nodes) is equal to or greater than the number of interfaces K |, the topology graph generator 320 sets the transmission power to the transmission power

), A topology graph G _T can be generated.

In step 540, the channel assigning unit 330 may reset P _T , T to connect with the neighboring node based on the number of interfaces.

For example, the channel assigning unit 330 may set a link by the number of interfaces (| K |) and reset P _T , T to ensure connectivity between the GW node and neighboring nodes. In this case, the channel assignment can be performed for a plurality of mesh nodes, and the channel assignment can be performed in the order of a GW node, a non-edge node, and an edge node.

).In operation 550, the channel assigning unit 330 may perform channel assignment on the GW node

).

을 찾을 수 있다. 그리고, 채널 할당부(330)는 이웃 노드의 집합에 포함된 이웃 노드들을 대상으로 트라이앵글 토폴로지(triangle topology) 생성을 방지하기 위한 링크 선택 프로세스를 수행할 수 있다. 여기서, 트라이앵글 토폴로지의 생성을 방지하는 프로세스는 도 7에서 후술하기로 한다. 이어, 채널 할당부(330)는 이웃 노드의 집합

에 포함된 복수의 이웃 노드들을 대상으로 각 링크(즉, GW 노드와 복수의 이웃 노드들 각각 간의 채널 링크,

)에 해당하는 모든 채널의 SINR을 계산할 수 있다. 그리고, 채널 할당부(330)는 복수의 이웃 노드들을 대상으로 SINR이 가장 높은 채널을 순차적으로 채널 할당 매트릭스 CA에 할당할 수 있다.For example, the channel assigning unit 330 assigns a set of neighbor nodes connectable at the GW node based on the topology proximity matrix T,

Can be found. The channel allocation unit 330 may perform a link selection process for preventing triangle topology generation from neighboring nodes included in the set of neighboring nodes. Here, the process for preventing the generation of the triangle topology will be described later in Fig. Then, the channel assigning unit 330 assigns a set of neighboring nodes

(I.e., a channel link between a GW node and a plurality of neighbor nodes,

) Can be calculated. The channel allocation unit 330 may sequentially allocate the channel having the highest SINR to the channel allocation matrix CA for a plurality of neighbor nodes.

). In step 560, the channel assigning unit 330 may perform channel assignment on all non-edge nodes (step < RTI ID = 0.0 >

).

At this time, as described in step 550, the channel assigning unit 330 can perform channel assignment for all non-edge nodes in the same process as that for the GW node. That is, based on the topology neighbor matrix T, a neighbor node set connectable at each non-edge node can be found for each non-edge node. In addition, the triangle topology generation prevention process can be performed, the SINR can be calculated for all the neighbor nodes included in the set of neighbor nodes, and the channel having the highest calculated SINR can be sequentially allocated to the CA, Assignment can be performed.

). In step 570, the channel assigning unit 330 may perform channel assignment for all the edge nodes (step < RTI ID = 0.0 >

).

At this time, as described in steps 550 and 560, the channel allocation unit 330 can perform channel allocation on all edge nodes in the same manner as that for allocating channels to GW nodes or non-edge nodes. For example, an operation may be performed in which a set of neighboring nodes is searched for each of the edge nodes, a triangle topology generation prevention process is performed, SINR calculation, and an operation of sequentially assigning the calculated channel having the highest SINR to the CA is performed.

In step 575, the channel assigning unit 330 may perform the connectivity enhancement for all the mesh nodes (GW node, edge node, and non-edge node) with respect to the node having one neighbor node connected to the corresponding node.

For example, the channel assigning unit 330 may be configured to assign a channel to a node, which is a currently connected neighbor node among all the mesh nodes (GW node, edge node, and non-edge node) Increasing power can be done to enhance connectivity to connect with other neighbor nodes. Here, the detailed operation for performing the connection enhancement will be described in detail with reference to FIG.

In step 580, the channel assigning unit 330 may minimize unnecessary transmission power based on the CA of the corresponding mesh node (GW node, edge node, and non-edge node).

For example, if the transmission power of a node corresponding to a predetermined value or more of the neighboring node is greater than a predetermined value, the channel allocation unit 330 may minimize the transmission power of the corresponding node according to the connection state of the neighboring node have.

In step 585, the channel allocation unit 330 may transmit and distribute the CA result that minimizes unnecessary transmission power, that is, the channel allocation matrix, to all the mesh nodes through a common channel.

In step 590, the channel assigning unit 330 may perform channel assignment according to the channel allocation matrix CA at a predefined specific time.

Figure 6 is a diagram provided to illustrate connectivity enhancement operations in one embodiment of the present invention.

In FIG. 6, connectivity enhancement may be performed on a mesh node having a neighboring node among a plurality of mesh nodes.

In Fig. 6, the solid line represents the link formed between the mesh nodes, and the dotted circle represents the range in which the beacon packet can be transmitted. For example, 601 indicates a range in which a beacon packet can be transmitted from the node A, and 602 indicates a range in which a beacon packet can be transmitted in the node B.

When the topology is formed as shown in 610, the node A 611 can recognize that there is one neighbor node formed with the link, and the node B 612 can confirm that there are two neighbor nodes formed with the link. At this time, by increasing the level of the transmission power of the node B 612 by one step, a link between the node A 611 and the node B 612 can be formed. For example, referring to 620, as the level of the transmission power of the node B 612 increases by one level, the dotted circle 602 can be extended as 603. Accordingly, a link 623 between the node A 621 and the node B 622 is formed, so that the connectivity of the node A 621 can be enhanced. As described above, through the enhancement of connectivity, the number of nodes formed with the link with the node A 621 becomes two, so that multi-path formation is possible, and as a result, traffic can be dispersed.

Figure 7 is a diagram provided to illustrate a process for preventing triangle topology generation in one embodiment of the present invention.

7 is a flowchart illustrating a method of performing channel allocation to all mesh nodes (GW node, edge node, and non-edge node) in steps 550 through 570 of FIG. 5, Figure 5 is a flow diagram illustrating the operation of a process for preventing nodes from being created in the form of a triangle topology.

7, neighboring nodes included in a set of neighboring nodes corresponding to a specific node (for example, a GW node, an edge node, or a non-edge node) among a plurality of mesh nodes are linked When the triangle topology 720 is formed, the channel assigning unit 330 assigns two triangles to each of the three nodes (nodes A, B, and C) It is possible to select any one of the links corresponding to the two neighboring nodes based on the SINR corresponding to the neighboring node.

For example, referring to 710, a node A and a node B are connected to form a link, and a link can be formed between the node A and the node C. At this time, if a node B and a node C are connected to form a link as in 720, a triangle topology in which nodes A, B, and C are connected in a triangle shape may be formed. At this time, referring to 730, when the node C is used as a reference, an interface and a channel can be efficiently used by selecting a link having a relatively higher SINR among the link AC 731 or the link BC 732 at the node C . That is, the link A-C 731 releases the connection and maintains the connection only with the selected link B-C 732, thereby preventing generation of a triangle topology in which a link is formed in a triangle shape between the nodes A, B, As described above, by selecting a link based on the SINR, it is possible to unnecessarily allocate an interface and a channel when a triangle topology is generated, thereby reducing or preventing an increase in interference and a phenomenon of degrading connectivity.

FIG. 8 is a diagram illustrating a result of performing topology control and channel allocation based on transmission and reception power measurements in an embodiment of the present invention.

8, the simulation environment of the topology control and channel allocation algorithm (i.e., the TCCA algorithm) may be as follows.

In the topology configuration, the mesh router may be configured as a grid of 5 * 5 (i.e., 25 mesh routers), and the distance between each node may be 170 meters. And, each mesh router can be rearranged within -60meter ~ 60meter from the grid current position randomly up and down, left and right. For example, if a network operator installs a mesh router arbitrarily in a wireless mesh network, it is inefficient and shows a large performance difference depending on the network configuration. Therefore, it is most efficient to construct a mesh router in a grid form, As mentioned above, mesh routers (i.e., mesh nodes) can be relocated within a grid-like current location randomly up and down, from -60 to +60 meters.

The simulation environment can be as shown in Table 2 below.

The operation of measuring the transmit / receive power corresponding to stage 1 (state 1) of the TCCA algorithm, that is, the stage 220 of FIG. 2, is completed within 5 seconds after the start of the simulation, and then the stage 2 of the TCCA algorithm, The topology graph generation and channel allocation graph generation operations corresponding to steps 230 and 240 of FIG. 2 may be completed within 10 seconds.

In this case, 100 TCP flows can be arbitrarily generated for a simulation time of 100 seconds, and the duration of each flow can follow the exponential distribution 10. In the traffic pattern, in the case of 50:50 traffic, half of the flows are traffic coming in and going out through the G / W mesh node, and the remaining flows may correspond to P2P traffic in the wireless mesh network. For 0: 100 traffic, all flows may correspond to P2P traffic in the wireless mesh network.

Performance analysis according to the HWMP routing protocol can be performed. For example, Proactive mode routing is performed to set up a routing path based on a GW mesh node, and reactive mode routing is performed to generate a path on-demand when a flow is generated. .

Table 3 below shows the transmission power results of each mesh node in tabular form.

Referring to FIG. 8 and Table 3, it can be confirmed that the channel is distributed evenly because the channel with the best SINR is allocated to the link. It can be confirmed that the transmission power of each node is set considering the distance from the neighboring node.

For example, in the case of node 7 810, it is not necessary to set the transmit power to be greater than 14 dBm to connect with neighboring nodes (node 6, node 8, node 12), and in case of node 21 820, It is necessary to set the transmission power to at least 21 dBm in order to connect to the nodes (node 16, node 22).

In FIG. 8, node 4 (830) and node 15 (840) may correspond to a node having two neighboring nodes through connection enhancement although there was initially one neighboring node.

For example, by increasing the level of transmission power of node 9 831 by one step, link 4-9 832 can be formed. Likewise, by increasing the level of the transmission power of the node 10 (841) by one step, links 10-15 (842) can be formed. Then, due to the link 4-9 (832) and the link 10-15 (842), the connectivity between the node 4 (830) and the node 15 (840) is enhanced and the traffic can be dispersed through the link.

8, a triangle topology in which a node set (nodes 7, 8 and 12), nodes 9, 10 and 14 and nodes 13, 14 and 18 are connected in a triangle form can be generated, Through a process of selecting one of the links having a relatively high SINR through the prevention process, the node corresponding to the node in which the triangle topology has not been generated. As described above, by preventing the generation of the triangle topology in advance, the link and the channel can be efficiently used, the capacity of the entire network can be increased, and the spatial channel usage can be enabled.

FIG. 9 is a graph showing a result of performance analysis of throughput and E2E delay time in an embodiment of the present invention, and FIG. 10 is a graph showing a result of performance analysis of HWMP proactive mode and reactive mode And the throughput.

The graphs of FIGS. 9 and 10 are graphs generated based on the average of the results of 10 runs for the exact results of the simulation. 9 and 10, as a result of the performance analysis, the transmission power of all the nodes may be the same when the same channel allocation method is used except for the power control part of the TCCA algorithm.

Referring to FIG. 9, a performance analysis result of the HWMP proactive mode is shown in 910 of FIG. 9, and a graph 920 is a graph showing a performance analysis result of a reactive mode.

Referring to the HWMP proactive mode 810, it can be seen that the TCCA algorithm performs better than the case power case in terms of throughput. Also, it can be confirmed that the TCCA algorithm has a remarkably good performance in the case of the E2E delay time. In the case of Same power, the topology is not optimized and the channel interference is high. However, the TCCA algorithm guarantees the connectivity of the GW node and controls the transmission power according to the mesh network topology. . In the proactive mode as a whole, since it is root-based routing, it can be confirmed that the performance degradation occurs as the traffic toward the GW node is crowded.

Referring to the HWMP reactive mode 920, it can be seen that the tendency is similar to the HWMP proactive mode (910). In other words, on-demand based reactive mode shows good performance when there are many P2P traffic. In addition, since the traffic is not transmitted to the GW node but is dispersed throughout the network, it can be confirmed that the delay time is lower than that in the proactive mode 910.

Referring to FIG. 10, in the case of 50:50 traffic, it can be seen that the proactive mode 1001 performs better than the reactive mode 1002.

It can be seen that in the case of 0: 100 traffic, the reactive mode 1003 exhibits better performance than the proactive mode 1004. According to FIG. 10, it can be seen that the performance is improved by selecting the HWMP routing protocol according to the traffic pattern in real time in the TCCA algorithm. For example, it can be seen that throughput is improved by using proactive mode when traffic is crowded with GW node and by using reactive mode when there is a large amount of P2P traffic.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions to be recorded on the medium may be those specially designed and configured for the embodiments or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI > or equivalents, even if it is replaced or replaced.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (18)

A method of power control and channel allocation in a wire mesh network,
Measuring transmission and reception power of a neighboring node for a plurality of mesh nodes included in the wireless mesh network;
Generating a topology graph GT corresponding to the wireless mesh network indicating link information between a plurality of mesh nodes and mesh nodes based on the measured transmit and receive powers; And
Allocating a channel corresponding to each of the plurality of mesh nodes based on the generated topology graph and Signal to Interference plus Noise Ratio (SINR)
Lt; / RTI >
Wherein the measuring step comprises:
Broadcasting a beacon packet at a predetermined transmit power for each predefined beacon period;
Measuring a received power when receiving an acknowledgment (ACK) packet as a response to the beacon packet;
Matching the transmission power and the reception power with an identifier of a corresponding mesh node to which the confirmation packet has been transmitted;
Updating the number of neighboring nodes connectable to the transmission power currently set in the beacon period based on the acknowledgment (ACK) packet; And
Incrementing the transmission power by one step until the number of updated neighbor nodes equals the number of interfaces
/ RTI > The method of claim 1, delete delete The method according to claim 1,
Wherein the received power and the transmit power measured when the beacon packet is received are matched with an identifier of a mesh node that has transmitted the beacon packet at a neighbor node that has received the beacon packet, Way. The method according to claim 1,
Wherein the assigning of the channel comprises:
When the number of the currently connected neighboring nodes is one among the plurality of mesh nodes, increasing the transmission power to perform connection enhancement so as to connect with other neighboring nodes
/ RTI > The method of claim 1, 6. The method of claim 5,
Wherein the traffic is distributed as the multipath is generated as the neighboring node is connected to the neighboring node through the connectivity enhancement. A method of power control and channel allocation in a wire mesh network,
Measuring transmission and reception power of a neighboring node for a plurality of mesh nodes included in the wireless mesh network;
Generating a topology graph GT corresponding to the wireless mesh network indicating link information between a plurality of mesh nodes and mesh nodes based on the measured transmit and receive powers; And
Allocating a channel corresponding to each of the plurality of mesh nodes based on the generated topology graph and Signal to Interference plus Noise Ratio (SINR)
Lt; / RTI >
Wherein the assigning of the channel comprises:
When a triangle topology in which three neighboring mesh nodes are connected to each other in a triangle shape is generated for the plurality of mesh nodes, two neighboring nodes, which are connected based on any one of the three mesh nodes, Selecting one of the links corresponding to the two neighboring nodes based on the SINR corresponding to the neighboring node
/ RTI > The method of claim 1, The method according to claim 1,
Wherein the assigning of the channel comprises:
Performing channel assignment in a sequence of a gateway (GW) node, a non-edge node, and an edge node connected to an external network among the plurality of mesh nodes
/ RTI > The method of claim 1, The method according to claim 1,
Wherein the assigning of the channel comprises:
Calculating an SINR of a channel corresponding to each of the neighboring nodes with respect to neighboring nodes capable of receiving a beacon packet;
Generating a channel matrix based on the calculated channel having the highest SINR;
Distributing the generated channel matrix to the plurality of mesh nodes through a common channel; And
Performing channel assignment at a predetermined specific time based on the distributed channel matrix
/ RTI > The method of claim 1, 1. A power control and channel allocation system in a wire mesh network,
A measurement unit measuring a transmission power and a reception power of a plurality of mesh nodes included in the wireless mesh network;
A topology graph generation unit for generating a topology graph GT corresponding to the wireless mesh network indicating link information between a plurality of mesh nodes and mesh nodes based on the measured transmission and reception powers; And
A channel allocation unit for allocating a channel corresponding to each of the plurality of mesh nodes based on the generated topology graph and SINR (Signal to Interference plus Noise Ratio)
Lt; / RTI >
Wherein the measuring unit comprises:
Broadcasting a beacon packet at a predetermined transmission power per predetermined beacon period, measuring reception power when receiving an acknowledgment (ACK) packet as a response to the beacon packet, and transmitting the transmission power and the reception power Matches the identifier of the mesh node to which the confirmation packet is transmitted,
Updates the number of neighboring nodes connectable with the transmission power currently set in the beacon period based on the acknowledgment (ACK) packet, and updates the transmission power until the updated number of neighboring nodes becomes equal to the number of interfaces Step-by-step
Wherein the power control and channel allocation system comprises: delete delete 11. The method of claim 10,
Wherein the received power and the transmit power measured when the beacon packet is received are matched with an identifier of a mesh node that has transmitted the beacon packet at a neighbor node that has received the beacon packet, system. 11. The method of claim 10,
The channel assigning unit,
If one of the plurality of mesh nodes is currently connected to one of the neighboring nodes, increasing the transmission power and enhancing connectivity so as to be connected to another neighboring node
Wherein the power control and channel allocation system comprises: 15. The method of claim 14,
And the traffic is distributed as the multipath is generated as the neighboring node is connected to the other neighbor through the connectivity enhancement. 1. A power control and channel allocation system in a wire mesh network,
A measurement unit measuring a transmission power and a reception power of a plurality of mesh nodes included in the wireless mesh network;
A topology graph generation unit for generating a topology graph GT corresponding to the wireless mesh network indicating link information between a plurality of mesh nodes and mesh nodes based on the measured transmission and reception powers; And
A channel allocation unit for allocating a channel corresponding to each of the plurality of mesh nodes based on the generated topology graph and SINR (Signal to Interference plus Noise Ratio)
Lt; / RTI >
The channel assigning unit,
When a triangle topology in which three neighboring mesh nodes are connected to each other in a triangle shape is generated for the plurality of mesh nodes, two neighboring nodes, which are connected based on any one of the three mesh nodes, And selecting one of the links corresponding to the two neighboring nodes based on the SINR corresponding to the neighboring node
Wherein the power control and channel allocation system comprises: 11. The method of claim 10,
The channel assigning unit,
Performing channel allocation in the order of a gateway (GW) node, a non-edge node, and an edge node connected to an external network among the plurality of mesh nodes
Wherein the power control and channel allocation system comprises: 11. The method of claim 10,
The channel assigning unit,
Calculates a SINR of a channel corresponding to each of neighboring nodes that are capable of receiving a beacon packet, generates a channel matrix based on the calculated channel having the highest SINR, Distributing the matrix to the plurality of mesh nodes via a common channel and performing channel assignment at a predetermined specific time based on the distributed channel matrix
Wherein the power control and channel allocation system comprises:

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