KR102192649B1 - Method and system for allocating slot based on TDMA(time division multiple access) in an Ad- hoc network - Google Patents

Abstract

In a slot allocation method for data transmission based on Time Division Multiple Access (TDMA) in an ad-hoc network composed of an upper node and a plurality of lower nodes, the upper node includes the number of lower nodes and Determine a plurality of transmission intervals to allocate slots based on the configuration state of the ad hoc network, and determine the AMC (Adaptive Modulation and Coding) level of each of the plurality of transmission intervals based on the channel environment of each of the plurality of transmission intervals And, based on the least common multiple of the AMC levels of the plurality of transmission intervals, a slot allocation ratio indicating a ratio to which a slot is allocated for each of the plurality of transmission intervals is determined, and according to the determined slot allocation ratio, a plurality of transmission intervals Assign a slot to each.

Description

(Method and system for allocating slot based on time division multiple access (TDMA) in an Ad-hoc network) in an ad-hoc network

The present disclosure relates to a TDMA-based slot allocation method and system in an ad hoc network.

In a wireless communication network, while demand for voice data and video data is rapidly increasing, transmission resources are limited, and thus, a technology that effectively allocates resources to a plurality of communication nodes is one of the essential technologies for supporting stable wireless communication network services.

Meanwhile, in general, ad hoc networks autonomously form networks between mobile nodes without the aid of a fixed infrastructure network. In particular, in a small ad hoc network of a private soldier system that must provide a multimedia service function between individual soldiers, voice data, battlefield data, and video data must be quickly and reliably delivered to all the individual soldiers in operation.

It is to provide a slot allocation method and system based on Time Division Multiple Access (TDMA) in an ad-hoc network.

The technical problem to be achieved by this embodiment is not limited to the technical problems as described above, and other technical problems may be inferred from the following embodiments.

According to an aspect of the present disclosure, a slot allocation method based on Time Division Multiple Access (TDMA) in an ad-hoc network composed of an upper node and a plurality of lower nodes includes the upper node Determining a plurality of transmission intervals to allocate the slot based on the number of lower nodes and the configuration state of the ad hoc network; Determining, by the upper node, an adaptive modulation and coding (AMC) level of each of the plurality of transmission intervals based on a channel environment of each of the plurality of transmission intervals; Determining, by the upper node, a slot allocation ratio indicating a ratio to which the slot is allocated to each of the plurality of transmission intervals, based on a least common multiple of AMC levels of the plurality of transmission intervals; And allocating, by the upper node, the slot to each of the plurality of transmission intervals according to the determined slot allocation ratio.

In addition, the slot allocation ratio for each of the plurality of transmission intervals may correspond to a ratio of the least common multiple of the AMC levels to the AMC level of each of the plurality of transmission intervals.

The determining of the slot allocation ratio may include determining, by the upper node, a slot allocation priority set for each of the upper node and a plurality of lower nodes; And determining, by the upper node, a priority allocation ratio for each of the transmission intervals based on the slot allocation priority, wherein the slot allocation ratio of each of the transmission intervals is the plurality of transmission intervals It may correspond to a value obtained by multiplying the ratio of the least common multiple of the AMC levels to the respective AMC levels by the priority allocation ratio of each of the plurality of transmission intervals.

In addition, in the plurality of transmission periods, a period in which each of the plurality of lower nodes transmits data to the upper node, and each of the plurality of lower nodes transmits data to the remaining plurality of lower nodes through the upper node. It may include a section.

In addition, the step of determining the slot allocation ratio may include, when the plurality of transmission intervals correspond to a period in which each of the plurality of lower nodes transmits data to the remaining plurality of lower nodes through the upper node, the The slot allocation ratio may be determined based on the lowest AMC level among the AMC levels of each of the transmission periods between the upper node and the plurality of lower nodes.

In addition, in the allocating step, the upper node determines the number of available slots through which the data can be transmitted, and the upper node determines the number of available slots for the sum of the slot allocation ratios of each of the plurality of transmission intervals. Calculate the number of proportional slots based on the ratio of, and the upper node calculates the number of slots obtained by multiplying the number of proportional slots by the slot allocation ratio of each of the plurality of transmission intervals for each of the plurality of transmission intervals. Can be assigned.

In addition, each of the upper node and the plurality of lower nodes may transmit at least one of voice data, professional data, and video data during slots allocated in the plurality of transmission intervals.

In addition, the upper node further comprises allocating a slot for transmitting the voice data and a slot for transmitting the specialized data for each of the plurality of transmission intervals, the slot for transmitting the voice data And slots for transmitting the full text data may correspond to a preset number of slots.

According to another aspect, a program for implementing a slot allocation method based on Time Division Multiple Access (TDMA) in an ad-hoc network consisting of an upper node and a plurality of lower nodes is recorded and read by a computer. A possible recording medium, the method comprising: determining, by the upper node, a plurality of transmission intervals to allocate the slot based on the number of the plurality of lower nodes and the configuration state of the ad hoc network; Determining, by the upper node, an adaptive modulation and coding (AMC) level of each of the plurality of transmission intervals based on a channel environment of each of the plurality of transmission intervals; Determining, by the upper node, a slot allocation ratio indicating a ratio to which the slot is allocated to each of the plurality of transmission intervals, based on a least common multiple of AMC levels of the plurality of transmission intervals; And allocating, by the upper node, the slot to each of the plurality of transmission intervals according to the determined slot allocation ratio.

According to another aspect, in order to execute a slot allocation method based on Time Division Multiple Access (TDMA) in an ad-hoc network consisting of an upper node and a plurality of lower nodes, combined with hardware In the stored computer program, the method includes the steps of: determining, by the upper node, a plurality of transmission intervals to allocate the slot based on the number of the plurality of lower nodes and the configuration state of the ad hoc network; Determining, by the upper node, an adaptive modulation and coding (AMC) level of each of the plurality of transmission intervals based on a channel environment of each of the plurality of transmission intervals; Determining, by the upper node, a slot allocation ratio indicating a ratio to which the slot is allocated to each of the plurality of transmission intervals, based on a least common multiple of AMC levels of the plurality of transmission intervals; And allocating, by the upper node, the slot to each of the plurality of transmission intervals according to the determined slot allocation ratio.

1 is a diagram for describing an example of an ad-hoc network system.
FIG. 2 is a diagram for explaining an example of a structure of a communication frame based on Time Division Multiple Access.
FIG. 3 is a diagram illustrating an example of nodes and AMC levels constituting an ad-hoc network.
4 is a diagram illustrating an example of a data slot allocation method in consideration of a channel environment of an entire ad hoc network.
5 is a diagram for explaining an example of a slot allocation priority set for nodes constituting an ad-hoc network.
6 is a diagram for describing an example of a slot allocation method in consideration of a channel environment and a slot allocation priority.
7 is a flowchart illustrating an example of a TDMA-based slot allocation method in an ad hoc network.

The terms used in the present embodiments have selected general terms that are currently widely used as possible while considering the functions in the present embodiments, but this varies depending on the intention or precedent of a technician engaged in the art, the emergence of new technologies, etc. I can. In addition, in certain cases, there are terms that are arbitrarily selected, and in this case, the meaning will be described in detail in the description of the corresponding embodiment. Therefore, the terms used in the present embodiments should be defined based on the meaning of the term and the overall contents of the present embodiments, not a simple name of the term.

In the descriptions of the embodiments, when a part is said to be connected to another part, this includes not only the case that it is directly connected, but also the case that it is electrically connected with another component interposed therebetween. . In addition, when a certain part includes a certain component, it means that other components may be further included, rather than excluding other components unless specifically stated to the contrary.

Terms such as "consist of" or "comprises" used in the present embodiments should not be interpreted as necessarily including all of the various components, or steps described in the specification, and some of the components or It should be construed that some steps may not be included, or may further include additional elements or steps.

The description of the following embodiments should not be construed as limiting the scope of the rights, and what those skilled in the art can easily infer should be construed as belonging to the scope of the embodiments. Hereinafter, embodiments for illustration only will be described in detail with reference to the accompanying drawings.

1 is a diagram for describing an example of an ad-hoc network system.

An ad-hoc network is a network that is autonomously configured between mobile nodes without the help of a fixed base network, giving the network autonomy and flexibility.

An ad-hoc network with a tree structure is a centralized network, and has the advantage of a simple network, but may have a disadvantage in that a lower node is disconnected when a transmission delay is large and a relay node leaves.

An ad-hoc network with a mesh structure is a distributed network, in which all nodes constituting the network are connected. Therefore, since all nodes are connected, there is an advantage in that transmission delay is small, but there may be a disadvantage in that overhead is large because the amount of control messages for maintaining the network is large.

In one embodiment, an ad hoc network system having a cluster-mesh structure in which the advantages of a tree structure and a mesh structure are combined may be disclosed.

1 is a diagram showing a multi-hop ad hoc network system in a cluster-mesh structure. Specifically, FIG. 1 is a diagram illustrating a 7-hop relay network system in a cluster-mesh structure.

Referring to FIG. 1, an ad hoc network system may include an upper node and a plurality of lower nodes.

The lower node is a general node and can be located at the end of the network. For example, the lower node may be referred to as a leaf node (LN) as shown in FIG. 1. However, the lower node is not limited to the LN, and other types of nodes may correspond to the lower node.

The upper node is a node that comprehensively manages the network, and may perform radio resource management, data relay, network management and control, and the like of connected lower nodes. For example, the upper node may be referred to as a primary cluster node (PCN) as shown in FIG. 1. However, the upper node is not limited to the PCN, and other types of nodes may correspond to the higher node.

Nodes constituting the ad hoc network system in FIG. 1 may further include a cluster node (hereinafter referred to as CN) and a disconnected node (hereinafter referred to as DN).

As a data relay node, the CN can relay voice, video and professional data as well as control data transmitted and received by the PCN and LN. DN may be a node that cannot access the network. The DN may be a node attempting to join the network or a node that has left the network due to poor communication.

In order to configure a cluster-mesh multi-hop ad-hoc network, nodes constituting the ad-hoc network must autonomously form a network, and various data including voice data, battlefield data, and video data are periodically transmitted between nodes. Should be. Hereinafter, in FIG. 2, a structure of a communication frame for periodically transmitting various data between nodes in a cluster-mesh multi-hop ad hoc network will be described.

FIG. 2 is a diagram for explaining an example of a structure of a communication frame based on Time Division Multiple Access.

FIG. 2 shows the structure of a communication frame 200 based on Time Division Multiple Access (TDMA) when up to three nodes access an ad hoc network. The communication frame 200 shown in FIG. 2 may have a length of 100 ms. In addition, for example, 250 slots may exist in the communication frame 200 of 100 ms length shown in FIG. 2. The slot may correspond to the least possible data allocation unit.

Meanwhile, the maximum number of nodes that can access the ad hoc network and the length of the communication frame 200 are not limited as described above. Accordingly, the structure of the communication frame 200 is not limited to FIG. 2 and may have various structures.

Referring to FIG. 2, the communication frame 200 includes a beacon slot section 210 for transmitting network control messages between nodes accessing an ad hoc network and a data slot section for transmitting data ( 220) may be included. In this case, among 250 slots in the communication frame, 226 slots may exist in the data slot section 220, but the present invention is not limited thereto.

The beacon slot section 210 may be composed of a plurality of beacon slots 211, and in the beacon slot 211, data related to network control such as routing information, resource allocation information, topology information, frequency information, and encryption key information Can be transmitted and received.

The data slot section 220 may be composed of a plurality of data slots 221, and data including at least one of audio data, image data, and professional data may be transmitted and received in the data slot 221.

The data slot section 220 may be divided into a plurality of transmission sections 230. In each transmission section 230, only one of the nodes constituting the ad-hoc network can transmit data. The transmission periods 230 constituting the data slot period 220 may be determined based on the number of lower nodes constituting the ad hoc network and the configuration state of the ad hoc network. For example, transmission intervals constituting the data slot interval may be determined based on the number of CNs, the number of LNs, and the maximum number of hops of the ad hoc network. Meanwhile, the data slot interval of FIG. 2 may be divided into three transmission intervals 230, but is not limited thereto, and various numbers of transmission intervals 230 may exist.

Meanwhile, in each transmission section 230 within the data slot section 220, data including at least one of voice data, video data, and specialized data can be transmitted and received, and the number of slots required for transmission is allocated according to the characteristics of each data. Can be.

First, voice data corresponds to important commands or essential data required for engagement in battlefield situations. Accordingly, voice data must be able to maintain communication regardless of the channel state of each node constituting the ad hoc network. Accordingly, in each transmission period 230 within the data slot period 220, a preset number of slots may be fixedly allocated so that voice data can be transmitted even in a poor channel condition.

For example, 226 slots may exist in the data slot period 220, and 226 slots may transmit 896 symbols. At this time, assuming that data is transmitted in the quadrature phase shift keying (QPSK) 1/3 mode for transmission of voice data in an environment where the channel condition is very poor, the bits that can be transmitted per one slot The number of can be 592 bits. Meanwhile, G.729, a commercial voice codec capable of transmitting 8000 bits for 1 second, requires 800 bits of data to be transmitted during a communication frame period having a length of 100 ms. Therefore, even in an environment in which the channel condition is very poor, since two slots can sufficiently transmit voice data, two slots can be fixedly allocated for transmission of voice data in each transmission section 230 in the data slot section 220. .

Similarly, battlefield data is of high importance as data that includes command and military information that can occur in battlefield situations. However, since the frequency of occurrence is not high, one slot may be fixedly allocated for transmission of full length data in each transmission period 230 in the data slot period 220 in consideration of the efficiency of allocating the entire data slot. In this case, the reliability of full-length data transmission can be maintained by adding division and retransmission functions according to the length of the full-length data.

Meanwhile, among audio data, full length data, and image data, the image data with the largest transmission amount may be allocated not fixedly but by variable allocation in consideration of the channel environment of the entire ad hoc network to satisfy the reliability and efficiency of image data transmission. Accordingly, the number of slots for transmission of image data in each transmission period 230 within the data slot period 220 may be differently and variably allocated for each transmission period 230.

3 is a diagram for explaining an example of an AMC level of transmission intervals formed between nodes constituting an ad hoc network.

Referring to FIG. 3, there may be a total of four nodes constituting the ad hoc network 300. Nodes of ID 1, ID 2, and ID 3 are located at the end of the ad hoc network 300 and may correspond to lower nodes that transmit and receive data. In addition, the node of ID 4 is a node with the shortest end hop count, and may correspond to an upper node that performs radio resource management and data relay of the nodes of ID 1, ID 2, and ID 3.

Meanwhile, a link adaptation technique may be used for the ad hoc network 300, and for example, an adaptive modulation and coding (AMC) technique may be used.

The AMC scheme is an efficient link adaptation scheme for transmission of multimedia data, and is an adaptation scheme that changes the transmission rate to suit the channel environment. The AMC scheme determines and transmits an appropriate transmission rate according to the characteristics of a channel, and the transmission rate may be determined by the AMC level.

The AMC level is a level for a predefined combination of modulation and channel coding. For example, a QPSK with a low modulation index and an enhanced channel coding method may be used in a condition in which the channel environment is poor, and a high modulation level and a low channel coding method may be used in a condition in which the channel environment is excellent.

Meanwhile, nodes constituting the ad hoc network 300 of FIG. 3 may transmit and receive data with each other. In the ad hoc network 300, the node with ID 4 corresponding to the upper node indicates the AMC level of the transmission section formed between nodes constituting the ad hoc network 300, among the five AMC levels according to the channel environment. You can decide on one level.

The higher the AMC level, the more data can be transmitted at the same time, and the amount of data transmitted at the same time can be increased by a multiple of the size of the AMC level. For example, the transmission interval between the node of ID 1 with AMC level 4 and the upper node with ID 4 is 4 times more data than the transmission interval between the node with ID 3 and ID 4 with the AMC level 1 Can be transmitted.

4 is a diagram illustrating an example of a data slot allocation method in consideration of a channel environment of an entire ad hoc network.

Specifically, FIG. 4 is a diagram illustrating a method of allocating a data slot in consideration of the channel environment of the entire ad hoc network 300 by a node of ID 4, which is an upper node, on the ad hoc network 300 of FIG. 3.

First, the upper node of ID 4 may determine a plurality of transmission intervals to allocate a data slot. The plurality of transmission periods may include a period in which each of the plurality of lower nodes transmits data to an upper node, and a period in which each of the plurality of lower nodes transmits data to the remaining plurality of lower nodes through the upper node. The upper node of ID 4 may determine seven transmission intervals to allocate a data slot based on the number of lower nodes of the ad hoc network 300 of FIG. 3 and the configuration state of the ad hoc network 300.

Referring to FIG. 4, each of transmission intervals 1 to 3 may correspond to intervals in which each of the lower nodes of ID 1, ID 2, and ID 3 transmits data to the upper node of ID 4. In addition, each of the transmission period 4 to the transmission period 6 may correspond to a period in which each of the lower nodes of ID 1, ID 2, and ID 3 transmits data to the remaining lower nodes through the upper node of ID 4. For example, transmission section 4 corresponds to a section in which the lower node of ID 1 transmits data to the lower node of ID 2 and the lower node of ID 3 through the upper node of ID 4. Lastly, the transmission period 7 may correspond to a period in which the upper node of ID 4 transmits data to each of the lower nodes of ID 1, ID 2, and ID 3.

The upper node of ID 4 may determine the AMC level of each of the transmission intervals to which the data slot is to be allocated. For example, the upper node of ID 4 may determine the AMC level of each of the transmission intervals 1 to 7 based on the channel environment of each transmission interval.

Meanwhile, in the case of transmission interval 4 to transmission interval 6, which is a period in which each of the lower nodes transmits data to the remaining plurality of lower nodes through the upper node of ID 4, the upper node of ID 4 and the remaining plurality of lower nodes The lowest AMC level among the AMC levels of each of the transmission intervals may be determined as the AMC level of each transmission interval. For example, in the case of transmission section 4, the AMC level of the transmission section between the lower node of ID 2 and the upper node of ID 4 is 2, and the AMC level of the transmission section between the lower node of ID 3 and the upper node of ID 4 is 1 Therefore, the AMC level may be determined as 1 which is the lowest value among them.

Similarly, in the case of transmission section 7, the AMC level of the transmission section between the upper node of ID 4 and the lower node of ID 1 is 4, the AMC level of the transmission section between the upper node of ID 4 and the lower node of ID 2 is 2, Since the AMC level of the transmission interval between the upper node of ID 4 and the lower node of ID 3 is 1, the AMC level may be determined as 1, the lowest value among them.

The upper node of ID 4 may determine the AMC level for each of the transmission intervals 1 to 7 and then calculate the LCM of the AMC levels of the transmission intervals 1 to 7. Referring to FIG. 4, the least common multiple of AMC levels in the transmission interval 1 to the transmission interval 7 may be 4.

The upper node of ID 4 may determine a slot allocation ratio indicating a rate at which data slots are allocated to each of the transmission intervals, based on the least common multiple of the AMC levels of the transmission intervals 1 to 7. The slot allocation ratio of each transmission period may be expressed as Equation 1 below.

Referring to Equation 1, the slot allocation ratio of each transmission interval may correspond to a ratio of the least common multiple of AMC levels of all transmission intervals in the ad hoc network to the AMC level of each transmission interval.

Meanwhile, as described above in FIG. 2, 226 slots may exist in a data slot section in one communication frame, and in each transmission section, two slots for transmission of voice data and one slot for transmission of full length data are fixed. Can be assigned as

Therefore, as slots for transmission of voice data and full-length data are fixedly allocated to each of the transmission periods 1 to 7, 14 slots each for transmission of voice data and full-length data out of a total of 226 slots in the data slot period. And 7 slots may be fixedly allocated. Accordingly, the number of available slots that can be allocated for image data transmission among a total of 226 slots in the data slot period may be 205.

In the case where the priority of slot allocation is not set for each node constituting the ad hoc network 300 of FIG. 3, the upper node of ID 4 uses a proportional number of slots so that the data transmission efficiency is the same in each node. It can be calculated as in Equation 2.

Referring to Equation 2, the number of proportional slots may correspond to an integer value excluding a decimal point from the ratio of the number of available slots to the sum of the slot allocation ratios. Referring to FIG. 4, when 205, which is the number of available slots that can be allocated for image data transmission, is divided by 21, which is the sum of all slot allocation ratios for transmission intervals 1 to 7, the number of proportional slots is It can be seen that it becomes 9.

Next, the upper node of ID 4 may allocate a slot for each transmission interval by multiplying the number of available slots that can be allocated for image data transmission by a slot allocation ratio for each of the transmission intervals 1 to 7. The number of slots allocated to each transmission interval from the total number of available slots may be expressed as Equation 3 below.

Meanwhile, referring to FIG. 4, the data transmission amount is equal to 36 in all transmission intervals of transmission intervals 1 to 7. The data transmission amount is a value obtained by multiplying the AMC level of each transmission interval by the number of slots allocated to each transmission interval, and it can be seen that image data is transmitted evenly in all transmission intervals.

5 is a diagram for explaining an example of a slot allocation priority set for nodes constituting an ad-hoc network.

The connection relationship between nodes constituting the ad hoc network 500 of FIG. 5 may be the same as that of the ad hoc network 300 of FIG. 3. However, unlike FIG. 3, each of the nodes constituting the ad hoc network 500 of FIG. 5 may have a slot allocation priority set.

The slot allocation priority may be set for each node constituting the ad hoc network 500 according to a user's request. For example, the slot allocation priority can be defined as 4 levels, and each of the 4 priority levels is high quality (4 levels), medium quality (3 levels), low quality (2 levels), and screen OFF level (1 level). It can be classified as However, the number of steps for defining the slot allocation priority and the meaning of each step are not limited to the above description.

Meanwhile, the higher the slot allocation priority set for each node, the greater the amount of data transmission required may be. Accordingly, when a slot allocation priority is set for each node constituting the ad hoc network 500 according to a user's request, the slot allocation ratio may be determined in consideration of the priority allocation ratio according to the slot allocation priority. For example, the priority allocation ratio may be set to 2 times, 1 times, 0.5 times, and 0 times in the order in which the slot allocation priority level is higher.

6 is a diagram for describing an example of a slot allocation method in consideration of a channel environment and a slot allocation priority.

Specifically, FIG. 6 shows a method of allocating data slots in consideration of the channel environment and slot allocation priority of the entire ad hoc network 500 by the upper node ID 4 on the ad hoc network 500 of FIG. 5. It is a drawing showing.

First, the upper node of ID 4 may determine a plurality of transmission intervals to allocate a data slot, which is the same as described above in FIG.

The upper node of ID 4 may determine the AMC level of each of the transmission intervals 1 to 7 which are transmission intervals to allocate a data slot, and calculate the LCM of the AMC levels of the transmission interval 1 to 7. This is the same as described above in FIG. 4 and thus will be omitted.

The upper node of ID 4 may determine the slot allocation priority defined for each of the lower nodes of ID 1, ID 2, and ID 3. For example, the upper node of ID 4 may have 3 slot allocation priority, and the lower nodes of ID 1, ID 2, and ID 3 are assigned slots of 2nd, 1st, and 3rd steps, respectively. Priorities can be set.

The upper node of ID 4 may determine a priority allocation ratio for each of the transmission intervals 1 to 7 based on the slot allocation priority set for each node. The priority allocation ratio of each transmission interval may be determined according to a slot allocation priority of a node transmitting data in each transmission interval. For example, since the lower node of ID 1 transmits data in the transmission interval 1 and the transmission interval 4, the priority allocation ratio 1 corresponding to the slot allocation priority of step 2 may be determined in the transmission interval 1 and the transmission interval 4.

The upper node of ID 4 may determine a slot allocation ratio indicating a rate at which data slots are allocated for each of the transmission intervals 1 to 7. The slot allocation ratio of each transmission period can be expressed as Equation 4 below.

Referring to Equation 4, the slot allocation ratio may correspond to a value obtained by multiplying the ratio of the least common multiple of AMC levels to the AMC level of each transmission interval by the priority allocation ratio of each transmission interval. As described above, unlike the ad hoc network 300 of FIG. 3, each of the nodes constituting the ad hoc network 500 of FIG. 5 has a slot allocation priority set, so the slot allocation of each transmission section in consideration of the priority allocation ratio You can determine the rain.

The upper node of ID 4 can calculate the number of available slots that can be allocated for image data transmission among the total 226 slots in the data slot section, which is the same as described above in FIG. The number of available slots that can be allocated for image data transmission may be, for example, 205.

The upper node of ID 4 can calculate the number of slots allocated to each transmission section from the total number of available slots. The number of slots allocated to each transmission period may be expressed as Equation 5 below.

Referring to Equation 5 above, the number of slots allocated to each transmission interval corresponds to an integer value excluding the decimal point from a value obtained by multiplying the ratio of the slot allocation ratio of each transmission interval to the sum of the slot allocation ratios by the number of available slots. I can.

Referring to FIG. 6, it can be seen that the data transmission amount of each of the transmission intervals 1 to 7 is not the same as in FIG. 4. Specifically, it can be seen that the data transmission amount of the lower node of ID 3 and the upper node of ID 4 requesting high-definition data transmission is the largest, and the data transmission amount of the lower node of ID 2 requesting low-quality data transmission is the smallest. have. In this way, when a slot allocation priority is set for each node according to a user's request, resources may be differentially allocated to each transmission section according to the slot allocation priority.

7 is a flowchart illustrating an example of a TDMA-based slot allocation method in an ad hoc network.

In step 710, the upper node may determine a plurality of transmission intervals to allocate a slot based on the number of the plurality of lower nodes and the configuration state of the ad hoc network. The plurality of transmission periods may include a period in which each of the plurality of lower nodes transmits data to an upper node, and a period in which each of the plurality of lower nodes relays data to the remaining plurality of lower nodes through the upper node. . In the plurality of transmission periods, each of the upper node and the plurality of lower nodes may transmit at least one of voice data, professional data, and video data during an assigned slot.

In step 720, the upper node may determine an AMC (Adaptive Modulation and Coding) level of each of the plurality of transmission periods based on a channel environment of each of the plurality of transmission periods. When the plurality of transmission periods correspond to a period in which each of the plurality of lower nodes relays data to the remaining plurality of lower nodes through the upper node, the AMC of each of the transmission periods between the upper node and the remaining plurality of lower nodes The lowest AMC level among the levels may be determined as the AMC level of the corresponding section.

In step 730, the upper node may determine a slot allocation ratio indicating a ratio at which a slot is allocated to each of the plurality of transmission intervals, based on the least common multiple of AMC levels of the plurality of transmission intervals. The slot allocation ratio for each of the plurality of transmission intervals may correspond to a ratio of the least common multiple of AMC levels to the AMC level of each of the plurality of transmission intervals.

In step 740, the upper node may allocate a slot to each of the plurality of transmission intervals according to the determined slot allocation ratio. For example, the upper node may determine the number of available slots through which data can be transmitted, and calculate the number of proportional slots based on a ratio of the number of available slots to the sum of the slot allocation ratios of each of the plurality of transmission periods. The upper node may allocate the number of slots equal to the number of proportional slots multiplied by the slot allocation ratio of each of the plurality of transmission intervals for each of the plurality of transmission intervals.

Meanwhile, the above-described embodiments of the present invention can be written as a program that can be executed on a computer, and can be implemented in a general-purpose digital computer that operates the program using a computer-readable recording medium. In addition, the structure of the data used in the above-described embodiment of the present invention can be recorded on a computer-readable recording medium through various means. The computer-readable recording medium includes a storage medium such as a magnetic storage medium (eg, ROM, floppy disk, hard disk, etc.), and an optical reading medium (eg, CD-ROM, DVD, etc.).

So far, the present invention has been looked at around its preferred embodiments. Those of ordinary skill in the art to which the present invention pertains will be able to understand that the present invention can be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from an illustrative point of view rather than a limiting point of view. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope equivalent thereto should be construed as being included in the present invention.

Claims (10)

In the TDMA (Time Division Multiple Access)-based slot allocation method in an ad-hoc network composed of an upper node and a plurality of lower nodes,
In order to allocate the slot to a plurality of transmission intervals that divide a data slot for data transmission included in a communication frame, the upper node is based on the number of the plurality of lower nodes and the configuration state of the ad hoc network. Determining the plurality of transmission intervals;
Determining, by the upper node, an adaptive modulation and coding (AMC) level of each of the plurality of transmission intervals based on a channel environment of each of the plurality of transmission intervals;
Determining, by the upper node, a slot allocation ratio indicating a ratio to which the slot is allocated to each of the plurality of transmission intervals, based on a least common multiple of AMC levels of the plurality of transmission intervals; And
The upper node allocating the slot to each of the plurality of transmission intervals according to the determined slot allocation ratio,
The slot allocation ratio for each of the plurality of transmission intervals corresponds to a ratio of the least common multiple of the AMC levels to the AMC level of each of the plurality of transmission intervals. delete The method of claim 1,
The step of determining the slot allocation ratio,
Determining, by the upper node, a slot allocation priority set for each of the upper node and a plurality of lower nodes; And
The upper node further comprises determining a priority allocation ratio for each of the transmission intervals based on the slot allocation priority,
The slot allocation ratio of each of the transmission intervals corresponds to a value obtained by multiplying the ratio of the least common multiple of the AMC levels to the AMC level of each of the plurality of transmission intervals by the priority allocation ratio of each of the plurality of transmission intervals. Way. The method of claim 1,
The plurality of transmission intervals,
And a section in which each of the plurality of lower nodes transmits data to the upper node, and a section in which each of the plurality of lower nodes relays data to the remaining plurality of lower nodes through the upper node. The method of claim 4,
The step of determining the slot allocation ratio,
When the plurality of transmission intervals correspond to a period in which each of the plurality of lower nodes relays data to the remaining plurality of lower nodes through the upper node,
A method of determining the slot allocation ratio based on the lowest AMC level among AMC levels of transmission intervals between the upper node and the plurality of remaining lower nodes. The method of claim 1,
The allocating step,
The upper node determines the number of available slots through which data can be transmitted,
The upper node calculates the number of proportional slots based on a ratio of the number of available slots to the sum of the slot allocation ratios of each of the plurality of transmission intervals,
The upper node allocates a number of slots equal to the number of the proportional slots multiplied by the slot allocation ratio of each of the plurality of transmission intervals for each of the plurality of transmission intervals. The method of claim 1,
Each of the upper node and the plurality of lower nodes transmits at least one of audio data, professional data, and video data during slots allocated in the plurality of transmission intervals. The method of claim 7,
The upper node further comprises allocating a slot for transmitting the voice data and a slot for transmitting the specialized data for each of the plurality of transmission intervals,
The slot for transmitting the voice data and the slot for transmitting the full text data correspond to a preset number of slots. In a computer-readable recording medium in which a program for implementing a slot allocation method based on TDMA (Time Division Multiple Access) in an ad-hoc network consisting of an upper node and a plurality of lower nodes is recorded ,
The above method,
In order to allocate the slot to a plurality of transmission intervals that divide a data slot for data transmission included in a communication frame, the upper node is based on the number of the plurality of lower nodes and the configuration state of the ad hoc network. Determining the plurality of transmission intervals;
Determining, by the upper node, an adaptive modulation and coding (AMC) level of each of the plurality of transmission intervals based on a channel environment of each of the plurality of transmission intervals;
Determining, by the upper node, a slot allocation ratio indicating a ratio to which the slot is allocated to each of the plurality of transmission intervals, based on a least common multiple of AMC levels of the plurality of transmission intervals; And
The upper node allocating the slot to each of the plurality of transmission intervals according to the determined slot allocation ratio,
The slot allocation ratio for each of the plurality of transmission intervals corresponds to a ratio of a least common multiple of the AMC levels with respect to the AMC level of each of the plurality of transmission intervals. In a computer program stored in a medium to execute a slot allocation method based on Time Division Multiple Access (TDMA) in an ad-hoc network consisting of an upper node and a plurality of lower nodes combined with hardware,
The above method,
In order to allocate the slot to a plurality of transmission intervals that divide a data slot for data transmission included in a communication frame, the upper node is based on the number of the plurality of lower nodes and the configuration state of the ad hoc network. Determining the plurality of transmission intervals;
Determining, by the upper node, an adaptive modulation and coding (AMC) level of each of the plurality of transmission intervals based on a channel environment of each of the plurality of transmission intervals;
Determining, by the upper node, a slot allocation ratio indicating a ratio to which the slot is allocated to each of the plurality of transmission intervals, based on a least common multiple of AMC levels of the plurality of transmission intervals; And
The upper node allocating the slot to each of the plurality of transmission intervals according to the determined slot allocation ratio,
The slot allocation ratio for each of the plurality of transmission intervals corresponds to a ratio of the least common multiple of the AMC levels with respect to the AMC level of each of the plurality of transmission intervals.

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