KR101753681B1 - Method for Distributed Call Admission Control for Distributed-TDMA Mobile Adhoc network - Google Patents

Abstract

A distributed call admission control method according to the present invention includes: a CTS occupancy determination step of receiving a frame for determining a vacant CTS occupation information in a predetermined hop that a first node can occupy; A firing message transmission step in which the first node transmits its own firing message when the CTS occupation succeeds without collision with another node; The second node receives the firing message, and when the JR flag indicating that the first node is a new participating node is set to 1 in the firing message, the second node transmits the firing message to the local network participating nodes A network ID comparison step of comparing the network ID information with the network ID information; A first firing message broadcasting step of broadcasting a firing message by setting a JR flag for a new node ID to 1 in a CTS occupation period of a local network participant node when the comparison result shows that there is no network ID or another network ID; If the ratio of the number of the participating nodes within the range of the neighboring nodes in the certain hop is set to 1 within the allowable range, if the ratio of the NCS flag associated with the network congestion state is within the allowable range, then each node sets the JC flag to 1 to broadcast the firing message. And a message broadcasting step.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a distributed admission control method for a TDMA mobile ad hoc network,

The present invention relates to a distributed call admission control method and a call admission control apparatus of a time division multiple access (TDMA) scheme in a mobile ad hoc network.

In the mobile ad hoc network environment, the wireless resource bandwidth characteristics are very poor compared to the services that can be provided under the fixed base station infrastructure due to restriction of transmission / output of the terminal, battery, and computing resource when sharing the multi - In particular, since the MAC layer corresponding to the second layer of the OSI 7 layer is a structure in which wireless resources are distributed among the terminals without central control, the end-to-end QoS is significantly influenced by the occupation efficiency of the wireless resources.

Generally, the MAC applied in the mobile ad hoc network environment is most widely applied to the competition based CSMA / CA and collision free D-TDMA structure. The contention-based CSMA / CA occupies radio resources through preemption for channel access whenever data transmission is required. If the channel is currently being used by another node, it waits for a certain amount of time through random back-off and then retries the use of the channel. CSMA / CA has a high probability of being occupied by other nodes in a high-density and high-hop environment in a local network. On the other hand, in the case of the D-TDMA having the collision free property, since the occupation time slot is ensured after the data time slot occupation through the control channel is succeeded, the performance deterioration by other nodes does not occur . In other words, even in an environment where the node density is high and the number of hops is high in the local network, it is possible to maintain the QoS of a certain level by guaranteeing the occupation of data time slot for each node.

However, D-TDMA is a structure that receives data slots in a frame according to the number of participating nodes in a distributed environment, so that as the number of participating nodes increases, occupancy of data slots decreases and frequent bottlenecks may occur. As a result, there is a problem that the overall network performance deterioration and the service QoS quality deteriorate.

Accordingly, it is an object of the present invention to provide a method and apparatus for controlling the number of nodes in an ad hoc environment so as to maintain an acceptable number of nodes in a local network in consideration of the amount of traffic and the number of occupied nodes, Method.

In addition, the present invention restricts the number of new nodes through exchange of bit flag information between local networks while maintaining the distributed structure of existing D-TDMA, thereby preventing bottleneck regions and improving quality of network service QoS.

According to an aspect of the present invention, there is provided a method for controlling a distributed call admission control method of a time division multiple access (TDMA) scheme in a mobile ad hoc network, the method comprising: A CTS occupancy judgment step of receiving a frame for judging information; A firing message transmission step in which the first node transmits its own firing message if the CTS occupation is successful without colliding with another node; The second node receives the firing message, and when the JR flag indicating that the first node is a new participating node is set to 1 in the firing message, the second node transmits the firing message to the local network participating nodes A network ID comparison step of comparing the network ID information with the network ID information; A first firing message broadcasting step of broadcasting a firing message by setting a JR flag for a new node ID to 1 in a CTS occupation period of a local network participant node when the comparison result shows that there is no network ID or another network ID; If the ratio of the number of the participating nodes within the range of the neighboring nodes in the certain hop is set to 1 within the allowable range, if the ratio of the NCS flag associated with the network congestion state is within the allowable range, then each node sets the JC flag to 1 to broadcast the firing message. A message broadcasting step; And when the first node is a new participating node, receiving a firing message set to a JC flag of 1 from a participating node existing on its CTS, the first node selects information occupied by selecting an empty DTS And a data transmission step of broadcasting the data through a firing message.

According to one embodiment, the firing message includes a 'Join Request', 'JC (Join Confirm)', 'NCS (Network Congestion Status)', 'SR (Seamless Request) Bit flag information of " 1 "

According to one embodiment, the network congestion state can be determined based on the amount of packet bytes that are queued to individual nodes in the local network using the firing message and the ratio to the allocated data time slots.

According to an embodiment, when the JR flag is set to '1' in the network ID comparison step, and the comparison results match the network ID information of the participant nodes, the first node may be determined as a temporary leave node.

According to one embodiment, in the network ID comparison step, when the JR flag is set to 1 and the comparison result is identical to the network ID information of the participating nodes, if the SR (Seamless Request) flag is set to 0, 1 fireing message broadcasting step is performed and the second firing message broadcasting step is performed without considering the setting ratio without performing the first firing message broadcasting step when the SR flag is set to 1 .

According to one embodiment, when the first node refuses to join the new participating node to the local network, next network link selection for load balancing may be performed.

Therefore, the call admission control method according to the present invention is advantageous in that call admission control of an adaptive new participant node can be performed according to the network congestion state of the local network with only a small overhead through bit flag information in the D-TDMA environment.

In addition, the call admission control method according to the present invention can prevent the bottlenecks occurring in the local network and induce the access to the next-order local network, thereby improving overall QoS of the load balancing and end-to-end network service There are advantages.

FIG. 1 illustrates a distributed call admission control method using bit flag information of a local Firing Message under a frame structure of a D-TDMA according to the present invention.
2 shows an example of the operation of a new participating node (before network entry) and an existing node (temporary network withdrawal) according to the present invention.
FIG. 3 shows an example of the operation of a roaming participation node (after network entry) and an existing node (temporary network withdrawal) according to the present invention.
4 shows a flowchart of a distributed call admission control method of a time division multiple access (TDMA) scheme in a mobile ad hoc network according to the present invention.
FIG. 5 shows a configuration diagram of a call admission control system including a time division multiple access type call admission control device in a mobile ad hoc network according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, It will be possible. The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Like reference numerals are used for similar elements in describing each drawing.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The term "and / or" includes any combination of a plurality of related listed items or any of a plurality of related listed items.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Should not.

The suffix "module "," block ", and "part" for components used in the following description are given or mixed in consideration of ease of specification only and do not have their own distinct meanings or roles .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The present invention relates to a distributed time division multiple access (D-TDMA) scheme for resource occupation of multi-hop multi-nodes among medium access control (MAC) schemes in a mobile ad hoc network environment (Hereinafter referred to as " D-CAC ") while maintaining a distributed structure without a central infrastructure (e.g. AP, base station, etc.).

To this end, the present invention proposes a method for determining a congestion state between nodes in a local network existing within two hops sharing a radio resource under the D-TDMA scheme. In the D-TDMA network, A call admission control method is proposed.

Each node sharing the radio resources in the local network can recognize its own congestion status according to the average amount of traffic accumulated in the queue compared to the time slot allocated to itself. It is possible to share information about the congestion state of the inter-node network within two hops by including the bit flag information in the time slot occupation information.

The present invention enables call admission control of a new participant node according to the network congestion state of the local network with very little overhead through bit flag information in a D-TDMA environment without a central infrastructure. As a result, it is possible to improve the quality of the overall network service QoS by preventing the bottleneck occurring in the local network and inducing load balancing that can be connected to the next-hop network without the bottleneck section.

Hereinafter, a distributed call admission control method of a time division multiple access (TDMA) scheme in a mobile ad hoc network according to the present invention will be described.

Generally, the D-TDMA includes a control time slot (CTS) for transmitting control information such as time occupancy information between neighboring nodes and a data time slot (DTS) for transmitting data traffic. And has a form of a frame structure of two channels. In CTS, to prevent collision between neighboring nodes, it transmits a broadcast message including its own time slot occupation information and time occupation information learned through its one hop neighbor node. In the present invention, the corresponding broadcast message is defined as a Firing Message.

FIG. 1 illustrates a distributed call admission control method using bit flag information of a local Firing Message under a frame structure of a D-TDMA according to the present invention.

As shown in FIG. 1, the local Firing Message of the D-TDMA includes a Local Network Identifier, Distributed Call Admission Control Information, Control Time Slot Allocation Information ), And data time slot occupancy information (Data Time Slot Allocation Information).

The local network ID information of the local Firing Message is used to identify a local network generated according to the inter-node propagation range. The local network ID is generated when at least two 'existing local network nodes' exist due to the radio wave reaching region that satisfies the minimum reception level, and a node newly entering the existing local network is referred to as a 'new participant node' define. A new participant node is newly powered up or a participant node of another local network enters due to mobility or the like.

The distributed call admission control information includes 'JR (Join Request)', 'JC (Join Confirm)', 'NCS (Network Congestion Status)', and 'SR (Seamless)' in the Firing Message packet, Request 'of the new participating node according to the network congestion state. The 'JR' flag information is a value that is set to '1' when the new participating node enters the local network, and is a value that the existing local network nodes identify the participation request of the new participating node. The 'JC' flag information is a value for determining whether the existing local network nodes request a new participating node requested by JR. If set to '1', it is allowed to occupy the data slot of the new participating node. The 'NCS' flag information is set by the existing local network nodes to determine the network congestion state of the local network through the NCS _ratio, and is determined using the following equation.

Here, the NCS _ratio is a value calculated for each local network node, and Q _threshhold , which is a queue threshold value, that is, Q ( u, t ) , a ratio of the number of packet bytes existing in the queue to the allocated data time slots Whether or not it is over. If Q ( u, t ) exceeds Q _threshhold , the NCS flag information is set to 1 for the corresponding value. The method of calculating Q (u, t) is calculated using the following equation.

Here, Q ( u, t ) is weighted moving average considering the variation of q ( u, t ) calculated for frame t of node u for each existing local network node. W _i of the weighted moving average is a weight value, and k is a value corresponding to a range parameter. Q (u, t), which means the amount of packet bytes present in the queue and the ratio to the allocated data time slots, is calculated using the following equation.

In this case, QueuePacketBytetotal (u) in q ( u, t ) means the amount of total average packets accumulated in the queue because the amount of data occupied slots is insufficient relative to the amount of packets to be transmitted by node u , and TimeSlotByte (u, t) Denotes the amount of data time slots allocated in frame t of node u.

The control time slot occupancy information means a time slot period occupied for transmitting a control message, a Firing Message. In order to transmit data traffic, a node in a local network must have a control time slot occupied and broadcast a firing message to the 1-hop node through the occupied control time slot. At this time, the Firing Message includes local network ID information, distributed call admission control information, control time slot occupation information, and data time slot occupation information received from the node itself and other nodes. However, the information of the other node collected in the Firing Message is the Hop Info. Field, and when the data time slot is occupied, Hop Info. Field is limited to information within two hops. The data time slot occupancy information means a time slot period for actual data packet transmission, and occupies the remaining period except the occupation period of another node within 2 hops identified from the Firing Message of the other node.

The procedure of the distributed call admission control method of the D-TDMA according to the present invention is shown in FIG. In this regard, Fig. 2 shows an example of the operation of a new participating node (before network entry) and an existing node (temporary network withdrawal) according to the present invention. Figure 3 also shows an example of the operation of a roaming participation node (after network entry) and an existing node (temporary network departure) according to the present invention. Meanwhile, FIG. 4 shows a flowchart of a distributed call admission control method of a time division multiple access (TDMA) scheme in a mobile ad hoc network according to the present invention.

Referring to FIG. 4, the main procedures and features of the call admission control method according to the present invention are as follows.

The call admission control method includes a CTS occupancy determination step 404, a firing message transmission step 405, a network ID comparison step 406, a first firing message broadcasting step 407, a second firing message broadcasting step 408, 409 and data transfer steps 411-414.

The CTS occupancy determination step 404 receives a frame for determining the empty CTS occupation information in a predetermined hop that the first node can occupy.

In the network ID comparison step 406, when the CTS occupation is successful without collision with another node, the first node transmits its own firing message.

In the network ID comparison step 406, the second node receiving the firing message, if the JR flag indicating that the first node is a new participating node is set to 1 in the firing message, And compares the network ID information with the network ID information of the local network participation nodes through the network ID information.

If the comparison result indicates that there is no network ID or another network ID, the first firing message broadcasting step 407 sets the JR flag for the new node ID to 1 in the CTS occupation period of the local network participant node to broadcast a firing message do.

If the ratio of the NCS flag associated with the network congestion state set to 1 is within the allowable range for the number of participating nodes in the neighbor node range within a given hop, the second firing message broadcasting step 408 and 409 broadcasts the JC flag 1 to broadcast a firing message.

If the first node is a new participant node, the data transfer step 411 to 414 receives a firing message set to 1 by the JC flag from a participating node existing on its CTS, Empty DTS is selected and the occupied information is broadcast through the firing message.

At this time, the firing message includes a 4-bit flag of 'JR (Join Request)', 'JC (Join Confirm)', 'NCS (Network Congestion Status) Information is added.

On the other hand, the network congestion state is determined based on the ratio of the amount of packet bytes accumulated in the queue of individual nodes in the local network to the allocated data time slots using the firing message, as described above.

In the network ID comparison step 406, if the JR flag is set to '1' and the comparison result is identical to the network ID information of the participating nodes, the first node may be determined as a temporary leaving node.

In the network ID comparison step 406, if the JR flag is set to 1 and the comparison result indicates that the network ID information matches the network ID information of the participant nodes, if the SR (Seamless Request) flag is set to 0, Performing the firing message broadcasting step and, if the SR flag is set to 1, to perform the second firing message broadcasting step (407) without considering the setting rate, 409).

Next, with reference to FIG. 4, detailed procedures and features of the call admission control method according to the present invention will be described.

When the new participating node reaches the local network entry state of FIG. 3 in the pre-entry state of FIG. 2, the incoming participant node senses the received signal strength at step 402 in the local network entry. Generally, a new participant node preferentially selects a link having the strongest received signal strength when selecting a link. In step 404, frame reception is performed at least twice to grasp empty CTS occupation information within two hops that can be occupied by itself. The vacant CTS occupation information is grasped through the neighboring node's Firing Message, and an attempt to occupy the empty CTS is performed.

 If the CTS is successfully occupied without collision with another node, it is able to transmit / receive its own Firing Message in step 405. At this time, in the case of the new participating node, the 'JR' flag is set to '1' to broadcast the Firing Message, and the existing local network participating nodes neighboring one hop of the new participating node can receive the corresponding message. The existing local network participating nodes of the new participating node compare the network ID information of the existing local network participation nodes through the network ID information in step 406. If the network ID does not exist or is a different network ID, The 'JR' flag for the new node ID is set to '1' when broadcasting the Firing Message in the CTS occupation period of the CTS. In step 408, each node reflects the result of NCS (u, t) for grasping the network congestion state of the local network every frame, and reflects the NCS field in the Firing Message. If the '1' ratio of the NCS flag to the total number of existing local network participating nodes in the two-hop neighboring node range is within the allowable range in the network, each node sets the JC flag to '1' in step 409, Broadcast. In step 410, the network ID is the same as that of the existing local network. In this case, it is determined that the node has left the local network temporarily due to loss or mobility of the wireless channel, . If the node has temporarily left the data traffic while the data traffic is being transmitted, the 'SR' flag is set to '1' in step 410 and the 'JC' flag is set to '1' without going through steps 407 and 408 And send the Firing Message. In step 411, when the new participating node receives the Firing Message in which all existing local network participating nodes existing on its CTS have transmitted the 'JC' flag as '1', the new participating node determines that data transmission is permitted on the local network. In step 412, the new participant node selects an empty DTS and broadcasts the occupied information to the Firing Message. If the new participating node is normally reflected in the Firing Message of the existing local network node received in the CTS section with respect to the DTS information occupied by the new participating node in step 413, the data traffic of the new participating node can be transmitted in step 415. [ If the 'JC' flag is continuously received as '0' due to network congestion between existing local network nodes in step 414, the procedure is repeated by selecting the next link of the received signal strength, if necessary.

The distributed call admission control method of the time division multiple access scheme in the mobile ad hoc network according to the present invention has been described above. On the other hand, the contents described in the call admission control method can also be applied to the following call admission control apparatuses.

In this regard, FIG. 5 shows a configuration diagram of a call admission control system including a time division multiple access type call admission control apparatus in a mobile ad hoc network according to the present invention. As shown in FIG. 5, the call admission control system includes a first node 100 and a second node 200. Here, the first node 100 and the second node 200 may be a transmitting node and a receiving node, respectively. Meanwhile, in the next step, the first node 100 and the second node 200 may be a receiving node and a transmitting node, respectively.

The first node 100 may include a wireless communication unit 110 and a control unit 120. Also, the second node 200 includes a wireless communication unit 210 and a control unit 220.

The wireless communication unit 110 receives a frame for determining the empty CTS occupation information within a predetermined hop that the first node 100 can occupy. In addition, when the CTS is successfully acquired without collision with another node, the first communication node 110 transmits its own Firing Message.

The wireless communication unit 210 receives the firing message from the first node 100.

When the JR flag indicating that the first node is a new participant node is set to 1 in the firing message, the controller 220 determines whether the second flag is set to '1' according to the network ID information of the local network participating nodes .

Also, if the comparison result indicates that the network ID does not exist or is a different network ID, the wireless communication unit 210 broadcasts a firing message by setting the JR flag for the new node ID to 1 in the CTS occupation period of the local network participant node.

At this time, if the ratio of the number of the participating nodes within the range of the neighboring node in the certain hop is set within the allowable range of the NCS flag associated with the network congestion state to 1, the nodes can broadcast the firing message by setting the JC flag to 1 .

If the first node is a new participating node, the wireless communication unit 110 may receive a firing message in which the JC flag is set to 1 from a participating node existing on its CTS.

The control unit 120 controls the wireless communication unit 110 to broadcast the occupied information by selecting a vacant DTS through a firing message.

Therefore, the call admission control method according to the present invention is advantageous in that call admission control of an adaptive new participant node can be performed according to the network congestion state of the local network with only a small overhead through bit flag information in the D-TDMA environment.

In addition, the call admission control method according to the present invention can prevent the bottlenecks occurring in the local network and induce the access to the next-order local network, thereby improving overall QoS of the load balancing and end-to-end network service There are advantages.

According to a software implementation, not only the procedures and functions described herein, but also each component may be implemented as a separate software module. Each of the software modules may perform one or more of the functions and operations described herein. Software code can be implemented in a software application written in a suitable programming language. The software code is stored in a memory and can be executed by a controller or a processor.

100: First node 200: Second node
110, 210: wireless communication unit 120, 220:

Claims (6)

A distributed call admission control method of a time division multiple access (TDMA) scheme in a mobile ad hoc network,
A CTS occupancy determining step of receiving a frame for determining a vacant CTS occupation information in a predetermined hop that the first node can occupy;
A firing message transmission step in which the first node transmits its own firing message if the CTS occupation is successful without colliding with another node;
The second node receives the firing message, and when the JR flag indicating that the first node is a new participating node is set to 1 in the firing message, the second node transmits the firing message to the local network participating nodes A network ID comparison step of comparing the network ID information with the network ID information;
A first firing message broadcasting step of broadcasting a firing message by setting a JR flag for a new node ID to 1 in a CTS occupation period of a local network participant node when the comparison result shows that there is no network ID or another network ID;
If the ratio of the number of the participating nodes within the range of the neighboring node within the predetermined hop is set to 1 within the allowable range, if the ratio of the NCS flag associated with the network congestion state is within the permissible range, each node sets a JC flag to 1 to transmit a second firing message Broadcasting stage; And
If the first node is a new participating node, the first node receives the firing message set to the JC flag of 1 from the participating node existing on its CTS, the first node selects the empty DTS and obtains the occupied information And a data transmission step of broadcasting through a firing message. The method according to claim 1,
The firing message may include:
Bit flag information of 'JR (Join Request)', 'JC (Join Confirm)', 'NCS (Network Congestion Status)' and 'SR (Seamless Request)' for distributed call admission control is added , Call admission control method. The method according to claim 1,
Wherein the network congestion state includes:
And determining a ratio of the amount of packet bytes to be queued to individual nodes in the local network to the allocated data time slots using the firing message. The method according to claim 1,
In the network ID comparison step,
And determining that the first node is a temporary leaving node when the JR flag is set to 1 and the comparison results match the network ID information of the participating nodes. 5. The method of claim 4,
In the network ID comparison step,
If the JR flag is set to 1 and the comparison results match the network ID information of the participating nodes,
If the SR (Seamless Request) flag is set to 0, performing the first firing message broadcasting step,
Wherein if the SR flag is set to 1, the second firing message broadcasting step is performed without considering the setting ratio without performing the first firing message broadcasting step. The method according to claim 1,
And when the first node refuses to join the new participating node to the local network, the next network link selection for load balancing is performed.

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