KR101602039B1 - Apparatus for providing qos in wireless ad hoc networks - Google Patents

Abstract

The present invention relates to an apparatus for controlling quality of service in a wireless ad-hoc network, and more particularly, to a service quality control apparatus in a wireless ad-hoc network which determines whether a received RREQ message includes service quality data type information and includes service quality data type information, Calculates a cost function by assigning a weight according to each service quality type, and compares the cost of each path calculated to select an optimal path that is the lowest cost.

Description

[0001] APPARATUS FOR PROVIDING QOS IN WIRELESS AD HOC NETWORKS [0002]

The present invention relates to an apparatus for providing quality of service (QoS) in a wireless ad-hoc network, and more particularly, to an apparatus for providing quality of service To a destination node, a service quality control apparatus in a wireless ad-hoc network.

With the development of wireless network technology, users of various media services There is a growing demand for media transmission and research and development on media transmission in the wireless network is actively under way. In particular, media streaming should be able to transmit packets without delay, overcoming network fluctuations.

Accordingly, there is a growing interest in QoS indicating quality of service related to the transmission rate and error rate on the Internet or the network, and there is a growing need for wireless network development for reliably transmitting high-quality video and multimedia data.

On the other hand, among the links constituting the conventional network, a link having a transmission rate of 60% or less may not be useful for transmitting real-time multimedia traffic, but this link may be useful for transmitting a packet. In other words, the path may not be suitable for transmitting real time audio / video data, but it may be useful enough to transmit general data with low importance.

That is, since the file transfer, voice / video, and general data are different in degree from the required quality of service quality, using one path metric is not sufficient for various demands of the application program (reliability of data transmission, ) Is difficult to satisfy.

Korean Patent Publication No. 10-2011-0061609 (June 09, 2011)

Accordingly, it is an object of the present invention to provide a service quality control apparatus in a wireless ad-hoc network that improves data processing efficiency by selecting an optimal transmission path for each of file transmission, voice / image data, and general data.

A service quality data type determination unit for determining whether the corresponding node corresponds to a destination node and whether the service quality data type information is included based on the RREQ message, A path cost calculating unit for calculating a total cost function value according to the path by adjusting a weight value of each path metric cost function according to each quality of service data type based on the service quality data type, And an optimal path calculating unit for selecting a path.

The total cost function is obtained by using the following equation.

는 총 비용함수, α,β,γ 는 각 경로메트릭 비용함수에 적용되는 가중치 값, x는 Bottleneck 대역폭, y는 hopcount, z는 단 대 단 경로의 ETX 값을 의미하고, f(x)는 사용가능한 대역폭의 비용함수, g(y)는 단 대 단 경로에 대한 비용함수, h(z)는 ETX를 사용하는 경로의 비용함수이다.From here,

Is the total cost function, α, β, γ are weight values applied to each path metric cost function, x is the Bottleneck bandwidth, y is the hopcount, z is the ETX value of the shortest path, The cost function of the possible bandwidth, g (y), is the cost function for the shortest path, and h (z) is the cost function of the path using ETX.

Wherein the total cost function further uses an available bandwidth value calculated by the bandwidth measuring unit and an ETX value calculated by the ETX measuring unit.

Wherein the bandwidth measuring unit calculates a usable bandwidth value using a Hello message including a consumed bandwidth value.

The ETX measuring unit calculates the ETX in consideration of the actual data transmission amount when there is actual data transmission and calculates the ETX value using the Hello message as the probe packet when there is no actual data transmission.

And a path storage unit for storing path information of all the RREQ messages transmitted during the waiting time.

According to the apparatus for controlling quality of service in a wireless ad-hoc network according to the present invention, the improvement in data throughput and end-to-end delay are effective in transmitting data traffic for each application program .

1 is a configuration diagram of a service quality control apparatus in a wireless ad-hoc network according to a preferred embodiment of the present invention,
FIG. 2 is a flowchart of a method of controlling a service quality in a wireless ad-hoc network according to a preferred embodiment of the present invention;
FIG. 3 is a block diagram illustrating an optimal path selection algorithm according to a preferred embodiment of the present invention,
FIG. 4 is a graph illustrating a throughput and end-to-end delay of a video traffic according to a preferred embodiment of the present invention,
5 is a graph of the throughput and end-to-end delay of voice traffic according to a preferred embodiment of the present invention,
6 is a graph of the throughput and end-to-end delay of file transfer traffic according to a preferred embodiment of the present invention.

The present invention may have various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a configuration diagram of a service quality control apparatus in a wireless ad-hoc network according to a preferred embodiment of the present invention.

The transmission / reception unit 101 is configured in the service quality control apparatus of the present invention. The transmitting and receiving unit 101 transmits and receives an RREQ (Routing Request) message, an RREP (Routing Response) message, a Hello message, and data from an external node.

Here, the RREQ message is a message that the source node transmits to the neighbor node to find the route to the destination node when the route for packet transmission is not yet verified. The RREP message is a response message transmitted to the source node with respect to the received RREQ message if path information exists. The Hello message is a message periodically transmitted to a neighbor node to solve a problem of frequent route disconnection due to irregular movement of a node. The Hello message further includes a consumed bandwidth value.

The service quality traffic discrimination unit 102 is configured to receive the RREQ message obtained from the transceiver unit 101 and determine whether the node corresponds to a destination node and whether the node includes the quality of service data type information. Therefore, if the corresponding node does not correspond to the destination node, the service quality traffic discrimination unit 102 updates the bandwidth, ETX, and hop count information in the RREQ message header. On the other hand, if the corresponding node corresponds to the destination node, the service quality data type information included in the RREQ message is checked. If the RREQ message does not include the service quality data type information included in the RREQ message, the RREP transmission signal is transmitted to the transceiver 101 to transmit the RREP message to the source node. In the opposite case, All RREQ paths are transmitted to the path storage unit 105 and stored. Here, the waiting time is preferably half of the RREQ timeout period.

The route cost calculating unit 106 receives all the RREQ route information stored during the waiting time from the route storing unit 105 and calculates a total cost function value for each route using the total cost function of Equation 1 .

는 총 비용함수, α,β,γ 는 각 경로메트릭 비용함수에 적용되는 가중치 값, x는 Bottleneck 대역폭, y는 hopcount, z는 단 대 단(End to end) 경로의 ETX 값을 의미하고, f(x)는 사용가능한 대역폭의 비용함수, g(y)는 단 대 단 경로에 대한 비용함수, h(z)는 ETX를 사용하는 경로의 비용함수를 의미한다.In Equation (1)

X is the Bottleneck bandwidth, y is the hopcount, z is the ETX value of the end to end path, and f (x, y) is the total cost function. (x) is the cost function of the available bandwidth, g (y) is the cost function for the shortest path, and h (z) is the cost function of the path using ETX.

Although the total cost function is used on the basis of an Ad Hoc On-Demand Distance Vector Routing (AODV), it is also possible to use other methods such as Dynamic Source Routing (DSR), Optimized Link State Routing (OLSR), Topology Broadcast Based on Reverse Path Forwarding It can be applied to routing protocols.

In order to calculate the total cost function, the apparatus for controlling quality of service in an ad hoc network according to the preferred embodiment of the present invention includes a bandwidth measuring unit 103 for calculating a usable bandwidth value, and an ETX measuring unit (104).

The bandwidth measuring unit 103 receives the Hello message received from the transceiver 101 and calculates a usable bandwidth value for communicating with the external node using the consumed bandwidth value included in the Hello message .

The usable bandwidth value for communicating with the external node is calculated as follows.

In general, measuring the available bandwidth in the IEEE 802.11 MAC environment is quite difficult because there is no information about the data traffic state of neighboring nodes.

The available bandwidth between two neighboring nodes using the consumption bandwidth information transmitted together with the Hello message can be calculated by Equation (2).

In Equation (2), Bandwidth _AV denotes a usable bandwidth, Bandwidth _CH denotes a channel bandwidth, Bandwidth _CN denotes a total consumed bandwidth, and Weight_factor can be calculated using Equation (3).

The T _overhead value in Equation (3) means the _overhead value by the routing protocol and the MAC operation, and the value can be obtained using the following Equation (4).

In Equation (4), T _PHY denotes a physical layer preamble, T _MAC denotes a MAC header, T _UDP denotes a UDP header, T _IP denotes an IP header and an average backoff time, CW _min denotes a minimum contention window, T _slot denotes a time slot it means.

The ETX measuring unit 104 periodically calculates the packet transmission rate of the network, and calculates the ETX value according to whether data is transmitted or not.

That is, when there is actual data transmission, the ETX is calculated in consideration of the actual data transmission amount, and when there is no actual data transmission, the ETX value is calculated using the Hello message as a probe packet, Path cost calculating unit 106. The path-

ETX represents the number of transmissions including retransmission. The ETX value of each link is calculated through the forward and reverse rates of the link. In general, the ETX value is measured using the forward data rate and the reverse data rate of the probe packet transmitted on each link because the size of the probe packet is smaller than the actual size of the multimedia data packet transmitted. Therefore, the number of transmissions including the retransmission of each link It may not include exactly. Therefore, the present invention uses an improved ETX calculation method.

In the ETX calculation method of the present invention, ETX values are calculated in consideration of the actual transmission rate of the data packet, not the probe packet, and when the actual data is not transmitted, the ETX value is calculated using the probe packet.

When actual data is transmitted, the transmission rate is calculated using the following equation (5).

D _D (t) of the equation (5) is a packet transmission rate, AckCount (tT, t) for each link Acknowledgement value, DataCount (tT, t) stands for Data packet traffic value.

On the other hand, if the actual data is not transmitted, the transmission rate is calculated using Equation (6) below.

The d _H (t) of Equation (6) is prop-packet transmission rate, ProbeCount (tT, t) by the mean value of the total prop packet value, T / t of the probe packet received during T seconds be transmitted do.

D in Equation (7) is the transmission rates d _D (t) and d _H (t) calculated in Equations (5) and (6).

The path cost calculating unit 106 calculates a total cost function value for each path by adjusting a weight value applied to each path metric cost function according to each service quality data type.

The optimum path calculating unit 107 compares the total cost function values of the respective paths calculated by the path cost calculating unit 106 to determine the path with the lowest cost and selects the optimum path.

2 is a flowchart of a method of controlling a service quality in a wireless ad-hoc network according to a preferred embodiment of the present invention.

In the method of controlling quality of service in a wireless ad-hoc network according to a preferred embodiment of the present invention, the transceiver 101 receives an RREQ message transmitted from a source node (S201).

The RREQ message of the transceiver 101 is transmitted to the service quality traffic discriminator 102. Then, the service quality traffic discrimination unit 102 examines the RREQ message to determine whether the corresponding node is a destination node (S202).

If it is determined that the corresponding node is not a destination node, the service quality traffic discrimination unit 102 updates bandwidth, ETX, and hop count information in the RREQ message header (S203). However, if the corresponding node is the destination node, the service quality traffic discrimination unit 102 inspects the quality of service data type information included in the RREQ message (S204).

If the RREQ message does not include the service quality data type information as a result of checking the quality of service data type information, the quality of service traffic discrimination unit 102 determines that the quality of service ) To transmit the RREP message to the source node (S205). On the other hand, if the RREQ message includes the quality of service data type information, the quality-of-service traffic discrimination unit 102 stores all RREQ paths between the source node and the destination node during the waiting time in the path storage unit 105 (S206).

The RREQ information stored during the waiting time is transmitted to the path cost calculating unit 106. The path cost calculating unit 106 calculates the path cost using the total cost function of Equation (1) As a total cost function value (S207). At this time, the total cost function is as shown in Equation (1), and is calculated using the hop count, usable bandwidth value, and ETX value.

The optimal path calculating unit 107 compares the total cost function value calculated by the path cost calculating unit 106 and selects the path having the lowest cost among the calculated paths as the optimum path (S208).

As described above, it can be seen that the service quality control apparatus in the wireless ad-hoc network according to the preferred embodiment of the present invention selects the optimal path for transmitting data in the same manner. Therefore, it is possible to transmit data at low cost through an optimal path for each of file transmission and audio / video data.

Meanwhile, the optimal path for transmitting data through the service quality control method of FIG. 2 is implemented by the optimal path selection algorithm of FIG.

Next, simulation results of a service quality control apparatus in a wireless ad-hoc network of the present invention will be described.

FIGS. 4 to 6 are graphs of results of video / audio / file transmission traffic throughput and end-to-end delay according to a preferred embodiment of the present invention.

Here, the applied weight values and the set communication environment for each service quality type are shown in the following Tables 1 and 2.

4 is a graph illustrating throughput and end-to-end delay of video traffic according to a preferred embodiment of the present invention.

Referring to FIG. 4, FIG. 4A illustrates a video traffic throughput according to a service quality providing method (MPM), an AODV, and a DSR method in a wireless ad hoc network according to the present invention. Initially, the network is not overloaded, and all the protocols show sufficient performance.

However, since the MPM scheme selects the path having the highest bandwidth as the data connection increases, the throughput increases by up to 17% compared to the AODV and DSR schemes.

Figure 4 (b) shows the video traffic edge-to-edge delay according to the MPM, AODV, and DSR schemes. As the MPM scheme transmits the data considering the bottleneck bandwidth, , It can be seen that the short-term delay time is lower than the DSR method.

5 is a graph of the throughput and end-to-end delay of voice traffic according to a preferred embodiment of the present invention.

5A shows voice traffic throughput according to the MPM, AODV, and DSR schemes. Up to four data connections are not significantly different between the MPM scheme and the AODV and DSR schemes, , The throughput of MPM method is up to 82% higher than that of AODV and DSR method.

FIG. 5 (b) shows the voice traffic terminal delay according to the MPM, AODV, and DSR schemes. As the data connection increases, the delay increases in all the protocols. However, the ETX and bandwidth metrics The MPM scheme considered is significantly lower than the AODV and DSR schemes in terms of voice traffic edge delay.

6 is a graph of the throughput and end-to-end delay of file transfer traffic according to a preferred embodiment of the present invention.

6 shows the file transfer traffic throughput according to the MPM, AODV, and DSR schemes. The MPM scheme uses the ETX to minimize the contention between the loss path and the path, The throughput is up to 70% higher than that of the conventional system.

Figure 6 (b) shows the video traffic end-to-end delay according to the MPM, AODV, and DSR schemes. The MPM scheme has only a short delay compared to the AODV and DSR schemes have.

The embodiments of the present invention described in the present specification and the configurations shown in the drawings relate to the most preferred embodiments of the present invention and are not intended to encompass all of the technical ideas of the present invention so that various equivalents It should be understood that water and variations may be present. Therefore, it is to be understood that the present invention is not limited to the above-described embodiments, and that various modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims. , Such changes shall be within the scope of the claims set forth in the claims.

101: Transmitting /
102: service quality traffic discrimination unit
103: Bandwidth measuring unit
104: ETX measuring section
105: Path storage unit
106: path cost calculating unit
107: Optimum path calculating unit

Claims (6)

A receiving unit for receiving an RREQ message from an external node;
A quality-of-service traffic discrimination unit for determining whether the corresponding node corresponds to a destination node and whether the node includes the quality-of-service data type information based on the RREQ message;
A cost function for the available bandwidth, a cost function for the shortest path, and a cost function for the path using the ETX (Expected Transmission Count) based on the service quality data type information, A path cost calculating unit for calculating a total cost function value according to a path by adjusting a weight value of the metric cost function; And
And an optimal path calculating unit for comparing the total cost function values according to the path to select a path having the lowest cost for each data as an optimum path,
Wherein the total cost function is obtained using Equation (1). ≪ EMI ID = 1.0 >
[Equation 1]

From here,

Is the total cost function, α, β, γ are weight values applied to each path metric cost function, x is the bottleneck bandwidth, y is the hop count, and z is the ETX value of the shortest path. F (x) is the cost function of the available bandwidth, g (y) is the cost function for the shortest path, and h (z) is the cost function for the path using ETX.
delete The method according to claim 1,
Wherein the total cost function further utilizes the available bandwidth value calculated by the bandwidth measuring unit and the ETX value calculated by the ETX measuring unit.
The method of claim 3,
Wherein the bandwidth measuring unit calculates a usable bandwidth value using a Hello message including a consumed bandwidth value.
The method of claim 3,
Wherein the ETX measuring unit calculates an ETX in consideration of an actual data transmission amount when there is actual data transmission and calculates an ETX value using a hello message as a probe packet when there is no actual data transmission, A device for providing quality of service in a network.
The method according to claim 1,
And a path storage unit for storing path information of all the RREQ messages transmitted during the waiting time.

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