KR101574175B1 - Radio system and method for improving media access control - Google Patents

Abstract

The disclosed technology relates to a radio system and method that improves medium access control, and more particularly, to a radio system and method that improves medium access control, including a master node that periodically transmits a synchronization signal; And receiving the synchronization signal to form one network with the master node, and attempting communication by transmitting a first RCF (Request Control Frame) to any one of the nodes in the network, And a plurality of slave nodes transmitting a second RCF using a spare frame (RFUCF) of a superframe including the first RCF when a collision occurs during the second RCF. Therefore, the communication waiting time due to the collision of RCFs transmitted from different nodes is shortened, and the effect of mutual compatibility with the international standard is provided.

Description

TECHNICAL FIELD [0001] The present invention relates to a radio access system,

The disclosed technique relates to a radio system and method for improving media access control to prevent collisions.

The ISO / IEC 29157 international standard is used to establish a wireless communication network capable of transmitting and receiving various types of media data in a variety of applications from near-field, low-speed and low-power in the industrial, scientific and medical (ISM, Industry, Science, Medicine) It is a universal wireless communication technology standard that can be widely applied.

The ISO / IEC 29157 international standard is a synchronous network having a master-slave relationship in which a plurality of slave nodes synchronize with a synchronous signal periodically generated by one master node in the network. Therefore, the quality of service (QoS) is excellent, and commercialization in the field of voice and audio is proceeding successfully.

On the other hand, these ISO / IEC 29157 international standards can be used for digital radio systems that professionally support team-level activities. For example, it can be used for security activities, leisure activities or rescue activities. However, there is a problem that when a plurality of nodes existing in the network attempt to perform communication with any one node at the same time, collision occurs.

If a collision occurs between the nodes as described above, the node waits for a predetermined period of time and tries again to communicate. If the same situation is repeated continuously, the long-term communication may be interrupted.

Prior art relating to a radio system using the ISO / IEC 29157 international standard is disclosed in Korean Patent Publication No. 10-2013-0083946 entitled " Personal Space Service Convergence and Container-based Wireless Network " Protocol) and Korean Patent Laid-Open No. 10-2011-0059652 (entitled " Method and System for Supporting Interference-free Relaying between Near-Field Pico Cells).

The disclosed technique is to provide a radio system and method that improves medium access control to prevent communication disruption due to a collision.

According to a first aspect of the present invention, there is provided a communication system including a master node that periodically transmits a synchronization signal, a master node that receives the synchronization signal and forms one network with the master node, When a collision occurs during transmission of the first RCF, a second RCF (Request Control Frame) is transmitted using a spare frame (RFUCF) of the superframe including the first RCF, And a plurality of slave nodes transmitting the slave nodes.

According to a second aspect of the present invention, there is provided a method for transmitting a synchronization signal, the method including: periodically transmitting a synchronization signal at a master node; receiving a synchronization signal from a plurality of slave nodes to form a network with the master node; Transmitting a Request Control Frame (RCF) to communicate with a second node existing in the network at a first one of the plurality of slave nodes, waiting for a Request Acknowledge Control Frame (RACF) for the RCF, When a collision occurs by transmitting an RCF to communicate with the second node at at least one node different from the first node among the slave nodes and if the RACF is not received at the first node according to the collision, And transmitting the second RCF using a spare frame (RFUCF) of the superframe including the RCF And a radio transmission method in which medium access control is improved.

Embodiments of the disclosed technique may have effects that include the following advantages. It should be understood, however, that the scope of the disclosed technology is not to be construed as limited thereby, since the embodiments of the disclosed technology are not meant to include all such embodiments.

According to one embodiment of the disclosed technology, a radio system and method that improves medium access control provides the effect of shortening the communication latency due to the collision of RCFs as compared to a radio system using conventional international standards.

In addition, utilizing the spare frame included in the superframe, it provides an effect compatible with the standard of the conventional international standard.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a diagram of a radio system that improves media access control in accordance with one embodiment of the disclosed technique.
2 is a diagram illustrating a wireless method that improves media access control in accordance with one embodiment of the disclosed technique.
3 is a diagram showing a conventional super frame.
4 is a diagram of an improved superframe according to an embodiment of the disclosed technique.

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 should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, A, B, etc., may be used to describe various components, but the components are not limited by the terms, but may be used to distinguish 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. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that the singular < RTI ID = 0.0 > terms < / RTI > used herein should be interpreted to include a plurality of representations unless the context clearly dictates otherwise. And "comprises ", when used in this specification, specify the presence of stated features, numbers, steps, operations, elements, parts, or combinations thereof, Or combinations thereof, as a matter of course.

Before describing the drawings in detail, it is to be clarified that the division of constituent parts in this specification is merely a division by main functions of each constituent part. That is, two or more constituent parts to be described below may be combined into one constituent part, or one constituent part may be divided into two or more functions according to functions that are more subdivided.

In addition, each of the constituent units described below may additionally perform some or all of the functions of other constituent units in addition to the main functions of the constituent units themselves, and that some of the main functions, And may be carried out in a dedicated manner. Accordingly, the presence or absence of each component described in this specification should be interpreted as a function.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a diagram of a radio system that improves media access control in accordance with one embodiment of the disclosed technique. Referring to FIG. 1, a radio system having improved medium access control includes a master node 110 for periodically transmitting a synchronization signal, and a receiver for receiving the synchronization signal to form one network with the master node, When a collision occurs during the transmission of the first RCF, a preliminary frame (RFUCF) of the superframe including the first RCF is used to transmit a first RCF And a plurality of slave nodes 120 transmitting the second RCF.

Prior to the description of the disclosed technique, the radio system described herein is directed to radio terminals that perform low speed, low power, local area wireless communication in accordance with the ISO / IEC 29157 international standard. The wireless terminals perform the role of nodes and communicate with each other by continuously repeating the super frames conforming to the standards of the ISO / IEC 29157 international standard.

The master node 110 transmits a synchronization signal to a plurality of slave nodes 120. Referring to FIG. 1, a dotted line indicates a synchronization signal transmitted from the master node 110.

Meanwhile, the master node 110 transmits the synchronization signal according to a period in which the synchronization signal is input in advance. For example, it can be transmitted once per second or once every 0.5 seconds. Using the synchronization signal, the master node 110 and the slave nodes 120 form one network.

Meanwhile, the master node 110 and the plurality of slave nodes 120 use the same model or wireless terminal of the same model. According to an embodiment of the disclosed technology, the wireless terminal supports smooth communication with each other in performing activities on a team basis. For example, mountain rescue workers can be used as terminals capable of carrying out rescue activities and having each other carry out radio communication with each other.

Meanwhile, the master node 110 and the slave nodes 120 can perform mutually different roles. For example, one of the plurality of radio terminals may be selected as a master node, and the remaining radio terminals may be selected as a slave node. Of course, it is also possible to replace the master node with another radio terminal.

Meanwhile, a plurality of slave nodes 120 forming the network with the master node 120 transmit a first RCF (Request Control Frame) to any one of the nodes in the network to attempt communication. Each slave node 120 transmits an RCF to communicate with another node in the network.

Herein, the RCF is a kind of control frame for confirming whether the data can be received by the other party before transmitting any data as applied in the ISO / IEC 29157 international standard.

As mentioned earlier, in the ISO / IEC 29157 international standard, the RCF repeats a superframe in succession as one node transmits data to another node. Such a super frame includes a control frame for synchronizing the nodes and a payload frame for transmitting the actual data. The super frame will be described later in more detail with reference to FIG. 3 and FIG.

Referring again to FIG. 1, it is confirmed that each node exchanges data with each other by a solid line. However, if several nodes try to communicate with a particular node, for example, S1 and S2 send RCFs to communicate with S3, then an RCF collision occurs at S3.

In this case, S1 and S2 can not receive the RACF, which is a response to the transmitted RCF. Therefore, it is impossible to transmit the data to be transmitted, and communication is interrupted. Of course, the RCF can be transmitted once again by repeating the superframe having a length of 256 msec. However, since the same operation is repeated on the other side, there is a problem that it is desired to continuously repeat the time of 256 msec or to wait for a while on either side.

Of course, the period of 256 msec itself may not feel long. However, this is only a case where two nodes transmit to a specific node. If several nodes want to transmit RCF to one node, it may actually wait for much longer time.

Therefore, in order to solve this problem, the disclosed technique transmits the RCF again using the RFUCF, which is a spare frame included in the superframe. Hereinafter, the first transmitted RCF is referred to as a first RCF, and the second transmitted RCF is referred to as a second RCF.

The RFUCF is a reserved frame which is left to extend the function of the frame later in the ISO / IEC 29157 international standard. That is, the frame exists on the actual superframe but is empty. The spare frame consists of a total of three control frames. The slave nodes 120 transmit the RCF twice in one super frame of 256 msec using the spare frame.

As described above, the plurality of slave nodes 120 wait for the RACF, which is a response to the RCF transmitted first. If the RACF is not returned, it is determined that the first RCF transmitted has collided. And a second one of the three control frames of the spare frame is used as a second RCF.

Herein, the plurality of slave nodes 120 use the first frame of the spare frame as a RACF for the first RCF for a response to the first RCF transmitted. Hereinafter, the RACF is referred to as a first RACF.

If the first RACF is received in response to the first RCF, the plurality of slave nodes 120 determine that data transmission is possible between them and transmit data using the payload frame of the super frame. Data exchanged here is transmitted in a full duplex manner.

On the other hand, if the first RACF is not received, the slave nodes 120 use the second frame of the spare frame of the superframe including the first RCF as the second RCF. The superframe used in the conventional international standard transmits one RCF for a period of 256 msec. However, using the disclosed technique it is possible to transmit two RCFs during a 256 msec superframe.

Therefore, in the conventional case, when a collision occurs, at least one super frame must be waited for reuse of the RCF, but retry is possible within 256 msec by using the disclosed technique.

Assuming that there are n nodes to send RCFs in the same time zone, no matter how good backoff policy is used, the last slave node that can use RCF must wait at least 256 msec * (n-1) hours do.

However, using the method proposed by the disclosed technique, it is reduced to half of 256 msec * (n-1) hours. Therefore, the effect of significantly reducing the waiting time for reusing the RCF is provided.

2 is a diagram illustrating a wireless method that improves media access control in accordance with one embodiment of the disclosed technique. Referring to FIG. 2, the wireless LAN method improving the medium access control includes transmitting (210) a synchronization signal periodically at a master node, receiving a synchronization signal from a plurality of slave nodes, and forming a network with the master node In step 220, a Request Control Frame (RCF) is transmitted to the first node among the plurality of slave nodes to communicate with a second node in the network, and a Request Acknowledge Control Frame (RACF) A waiting step 230 and an RCF to communicate with the second node in at least one node that is different from the first node among the plurality of slave nodes to cause a conflict, (240) using a spare frame (RFUCF) of a superframe including the first RCF if the RACF is not received in the first RCF do.

In step 210, the master node periodically transmits a synchronization signal. The master node periodically transmits the synchronization signal to a plurality of slave nodes. Here, the master node and the slave node use the same model of radio terminals.

In step 220, a plurality of slave nodes receive the synchronization signal to form one network with the master node. The master node and the slave nodes are allowed to exchange voice, images, and images with each other in team-based activities through formed networks.

Here, the master node and the plurality of slave nodes can perform their roles by changing their roles. For example, one of the plurality of radio terminals may be selected as a master node, and the remaining radio terminals may be selected as a slave node.

Of course, it is also possible to replace the master node with another radio terminal. However, there is only one wireless terminal performing the role of the master node, and the wireless terminal performing the role of the remaining slave node includes a plurality of wireless terminals.

In step 230, the first node of the plurality of slave nodes transmits an RCF (Request Control Frame) to communicate with the second node existing in the network, and waits for a RACF (Request Acknowledge Control Frame) for the RCF. As described above with reference to FIG. 1, the disclosed technology repeats the superframe according to the ISO / IEC 29157 international standard to perform communication between the nodes.

In the superframe, sixteen combinations of one control frame and one payload frame are combined to have a period of 256 msec.

Meanwhile, the first node requests the use of the RCF in one superframe to communicate with the second node. And waits for the RACF to be returned in response to the RCF.

In the conventional case, one superframe includes one RCF and one RACF. However, in case of RCF, there is a possibility of collision due to competition with other nodes.

If there is a collision, one superframe contains one RCF, so wait for 256 msec to use RCF again. However, this is the case when the third node requests RCF at the same time when simply requesting the RCF from one node. In practice, a larger number of nodes can request an RCF, so it is possible to reuse the RCF only by waiting at least 256 msec.

At step 240, at least one node of the plurality of slave nodes transmits an RCF to communicate with the second node, and a collision occurs. In response to the collision, the first node transmits a RACF And if not, transmits a second RCF using a spare frame (RFUCF) of the superframe including the first RCF.

If the RACF according to the RCF transmitted from the first node is not received, it is determined that the RCF has collided. After waiting for a predetermined backoff time, a second RCF is transmitted using the spare frame of the super frame including the RCF.

In transmitting the second RCF, the disclosed technique uses three control frames that constitute the spare frame of the super frame. That is, the first control frame among the three control frames is allocated to the RACF of the RCF. And assigns the second control frame to the requesting RCF. The remaining third frame is left as a spare frame.

Here, assigning the first control frame to the RACF of the RCF that has been transmitted considers the case where the response is transmitted from the second node because there is no competitor to the RCF. If the first node receives the RACF from the second node, it is possible to exchange data using 16 payload frames of the superframe.

On the other hand, if the RACF is not received, the first node transmits a second RCF to the second node using the second control frame of the spare frame. The superframe used in the conventional international standard transmits one RCF for a period of 256 msec. However, using the disclosed technique it is possible to transmit two RCFs during a 256 msec superframe.

Therefore, in the conventional case, when a collision occurs, at least one super frame must be waited for reuse of the RCF, but retry is possible within 256 msec by using the disclosed technique.

Assuming that there are n nodes to send RCFs in the same time zone, no matter how good backoff policy is used, the last slave node that can use RCF must wait at least 256 msec * (n-1) hours do.

However, using the method proposed by the disclosed technique, it is reduced to half of 256 msec * (n-1) hours. Therefore, the effect of significantly reducing the waiting time for reusing the RCF is provided.

3 is a diagram showing a conventional super frame. The superframe is used in the ISO / IEC 29157 international standard. Referring to FIG. 3, a gray portion is a control frame and a white portion is a payload frame. The control frame and the payload frame are paired one by one, and the sixteen frames are combined to complete one super frame.

The superframe uses the 16 control frames to synchronize, control, and manage the network. As shown in FIG. 3, the first control frame and the third control frame are used as beacons, and the second control frame therebetween is used as the RCF. The remaining 16 payload frames except control frames are used to exchange data between actual nodes.

Meanwhile, as shown in FIG. 3, the superframe includes a frame called RFUCF. The RFUCF is a kind of preliminary frame, and the ISO / IEC 29157 standard is prepared in advance in order to expand future functions. Therefore, it is not used directly at this stage. This spare frame consists of a total of three control frames.

Meanwhile, as shown in FIG. 3, one RCF is included in one super frame. And RACF according to the RCF. In other words, one superframe contains one RCF, so if a node fails in the process of requesting an RCF, it must wait until it retransmits at least one superframe to request the RCF again.

4 is a diagram of an improved superframe according to an embodiment of the disclosed technique. Referring to FIG. 4, it can be confirmed that a spare frame mounted on a conventional superframe has one additional RCF using RFUCF.

As described above, since one RCF is included in one superframe, if the node fails to return a response according to the RCF request, it must wait at least one superframe time to request the RCF again.

However, as shown in FIG. 4, it is possible to request two RCFs in one super frame by utilizing three control frames constituting the spare frame.

In one embodiment, if a node in the network requests an RCF but does not receive a response, it may request a second frame, which constitutes a spare frame of the currently transmitted superframe, to a second RCF.

Here, the reason why the second frame of the spare frame is set as the second RCF is that the receiving node receives the first RCF and returns the RACF accordingly. That is, the first control frame of the spare frame is allocated to the RACF for the response to the requested RCF.

Then, the second control frame of the spare frame is requested by the second RFC. Naturally, the eighth control frame of the superframe is used as the RACF for the second RCF. Thus, it is possible to attempt two RCF requests and RACF replies in a single 256 msec superframe.

If the conventional superframe described with reference to FIG. 3 and the superframe proposed through FIG. 4 are compared with each other, even if a good backoff policy is used, a transmission delay of at least 256 msec occurs in the conventional case. However, A transmission delay corresponding to half of the transmission delay occurs.

If the number of slave nodes requesting the RCF in the same time period is n, a transmission delay of at least 256 * (n-1) occurs in the conventional superframe. However, in the disclosed technology, As shown in Fig.

It also has the advantage of being perfectly compatible with each other because of the same superframe as the ISO / IEC 29157 international standard. Therefore, it is possible to ensure efficient communication between the radio terminals.

Although a wireless communication system and a method for improving medium access control according to an embodiment of the disclosed technology have been described with reference to the embodiments shown in the drawings for the sake of understanding, they are merely illustrative and those skilled in the art It will be understood that various modifications and equivalent embodiments may be possible. Accordingly, the true scope of protection of the disclosed technology should be determined by the appended claims.

110: master node 120: slave node
210: synchronization signal transmission 220: network formation
230: RCF transmission and RACF standby 240: Crash and second RCF transmission

Claims (7)

A master node that periodically transmits a synchronization signal; And
Receiving the synchronization signal to form one network with the master node, attempting communication by transmitting a first RCF (Request Control Frame) to any one of the nodes in the network, and transmitting the first RCF And a plurality of slave nodes transmitting a second RCF using a spare frame (RFUCF) of a superframe including the first RCF if a collision occurs during the first RCF. 2. The method of claim 1, wherein the plurality of slave nodes comprise:
And a first frame of the spare frame is used as a first RACF (Request Acknowledge Control Frame) according to the first RCF. 2. The method of claim 1, wherein the plurality of slave nodes comprise:
And a second frame of the spare frame is used as the second RCF. 2. The method of claim 1, wherein the master node and the plurality of slave nodes,
A radio system having improved medium access control using radio terminals of the same model. Transmitting a synchronization signal periodically at a master node;
A plurality of slave nodes receiving the synchronization signal to form one network with the master node;
Transmitting a Request Control Frame (RCF) to communicate with a second node existing in the network at a first one of the plurality of slave nodes and waiting for a Request Acknowledge Control Frame (RACF) for the RCF; And
When a collision occurs by transmitting an RCF to communicate with the second node in at least one node different from the first node among the plurality of slave nodes and the RACF is not received at the first node according to the collision And transmitting a second RCF using a spare frame (RFUCF) of the superframe including the RCF of the first node. 6. The method of claim 5,
And a first frame of the spare frame is used as a RACF according to the RCF. 6. The method of claim 5,
And a second frame of the spare frame is used as the second RCF.

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