KR101887627B1 - Method and apparatus for transceiving a packet in a wireless communication system - Google Patents

Abstract

A method for transmitting and receiving a packet in a wireless communication system, comprising the steps of: a transmitting node transiting to a wakeup state when a packet to be transmitted is generated; The transmitting node transmitting a Sender Competition (SC) beacon requesting scheduling of the packet to be transmitted in the wakeup state; The transmitting node overhearing an SC beacon transmitted from at least one neighboring transmitting node; Determining, by the transmitting node, a transmission order of packets based on the scrambled SC beacons; The transmitting node receiving a receiver beacon from the receiving node; Confirming whether or not the transmitting node is in a transmission order of the determined packet when the receiving beacon is received; And determining, by the transmitting node, whether to transmit the packet according to the result of the checking.

Description

TECHNICAL FIELD The present invention relates to a method for transmitting and receiving a packet in a wireless communication system, and a device for supporting the same.

The present disclosure relates to a method and apparatus for transmitting and receiving packets in a wireless communication system. More particularly, the present invention relates to an apparatus and a method for supporting packet scheduling and packet collision avoidance methods.

As regards the packet transmission / reception method, it can be classified into asynchronous MAC protocol and synchronous MAC protocol.

The asynchronous MAC protocol method refers to a MAC protocol in which both nodes do not need to periodically transmit and receive frames in order to synchronize the nodes.

Therefore, the asynchronous MAC protocol method is (1) simple to implement and (2) is more energy efficient than the synchronous MAC protocol method.

The asynchronous MAC protocol can be roughly divided into (1) a sender-initiated (SI) method and (2) a receiver-initiated (RI) method.

The Sender-Initiated (SI) method refers to a preamble sampling method in which a transmitting node repeatedly transmits a preamble until a message is received from a receiving node.

On the other hand, the Receiver-Initiated (RI) method refers to a method in which, when data (or packet) is generated, a transmitting node waits in a wakeup state and then synchronizes with a beacon message sent from the receiving node.

The MAC protocol of the receiver-initiated method has an advantage of eliminating the channel occupation time due to preamble sampling and improving the throughput when compared with the MAC protocol of the Sender-Initiated method.

However, since the receiver-initiated MAC protocol method must keep the wake-up state of the transmitting node in order to receive the beacon sent by the receiving node, which is unknown when the transmitting node wakes up, the idle listening And energy consumption due to overhearing operation occurs.

It is an object of the present invention to provide a packet scheduling method between nodes when a plurality of transmitting nodes transmit packets in a contention manner.

It is another object of the present invention to provide a method for maintaining the operating state of a transmitting node in a sleep state until a packet transmission time is reached.

It is also an object of the present invention to newly define a method for avoiding a collision between packets.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

The present invention relates to a method for transmitting and receiving a packet in a wireless communication system, comprising the steps of: a transmitting node transiting to a wakeup state when a packet to be transmitted is generated; The transmitting node transmits a Sender Competition (SC) beacon requesting scheduling of the packet to be transmitted in the wakeup state, the SC beacon includes transmission node identifier information identifying the transmitting node, A data length field indicating a length of data to be transmitted by the transmitting node, and address information indicating an address of a receiving node to be transmitted by the transmitting node; The transmitting node overhearing an SC beacon transmitted from at least one neighboring transmitting node; The transmitting node determining a transmission order of packets based on the scrambled SC beacons, the transmission order of the packets being determined by adding 1 to the number of SC beacons; The transmitting node receiving a receiver beacon from the receiving node; Confirming whether or not the transmitting node is in a transmission order of the determined packet when the receiving beacon is received; And a step in which the transmitting node determines whether to transmit a packet according to the result of the check. When the receiving node receives the beacon, the transmitting node transmits the packet to be transmitted, A sleep state is maintained from a time point at which the receiver beacon is received until a transmission time point of the determined packet if the time point at which the beacon is received is not the transmission order of the determined packet, Are determined based on the data length field included in the SC beacon.

Also, in the present specification, when the receiving node detects a collision of a packet transmitted by transmitting nodes, it transmits a Collision Notification (CN) beacon indicating that a packet collision has occurred to the transmitting nodes step; Receiving, by the receiving node, a packet from a transmitting node that does not cause a collision of the packet after transmitting the CN beacon; Transmitting the CN beacon to the transmitting nodes that caused the packet to collide with the receiving node; The receiving node receiving a request beacon requesting scheduling of packet transmission from the transmitting nodes that caused the packet to collide; Transmitting, by the receiving node, a scheduling beacon that assigns scheduling to the transmitting nodes in order of receiving the request beacon from the transmitting nodes that caused the collision; And receiving the packet from the transmitting nodes that caused the collision according to the order of the allocated scheduling.

In addition, the present specification further includes a step of transmitting, when the receiving node detects that a packet is not received from the colliding transmitting nodes, a receiving beacon for confirming whether another transmitting node for transmitting the packet exists; And transitioning to a sleep state after a predetermined time when the receiving node detects that the another transmitting node does not exist.

In this specification, when a plurality of transmitting nodes transmit a packet in a contention-based manner, a packet scheduling method between the nodes is provided, thereby preventing collision between packets.

Also, in this specification, the operation state of the transmitting node is maintained in the sleep state until the time of packet transmission, and the power consumption of the node can be greatly reduced.

The effects obtained in the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description .

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the technical features of the invention.
1 is a diagram illustrating an example of a receiver initiated MAC protocol method.
2 is a diagram illustrating an example of a random backoff method in the RI-MAC protocol.
3 is a diagram illustrating an example of an RC-MAC protocol method.
4 is a diagram illustrating an example of a packet scheduling method of the CRI-MAC protocol proposed in the present specification.
5 is a diagram illustrating an example of a packet conflict resolution method of the CRI-MAC Protocol proposed in the present specification.
6 is a flowchart illustrating an example of a scheduling method of the CRI-MAC protocol proposed in the present specification.
7 is a flowchart showing an example of a packet collision avoiding method of the CRI-MAC protocol proposed in the present specification.
8 is a block diagram of a wireless communication apparatus according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

The suffix "module" and " part "for components used in the following description are given merely for ease of description, and the" module "and" part "

Meanwhile, the node described in this specification is a device capable of wireless communication, and can be applied to various devices such as a mobile phone including a smart phone, a tablet PC, a desktop computer, a laptop, a television including smart TV, IPTV and the like, a wearable device such as a smart watch, It is possible.

In the following, embodiments of the present invention will be described in detail with reference to the accompanying drawings and accompanying drawings, but the present invention is not limited to or limited by the embodiments.

As used herein, terms used in the present invention are selected from general terms that are widely used in the present invention while taking into account the functions of the present invention, but these may vary depending on the intention or custom of a person skilled in the art or the emergence of new technologies.

In addition, in certain cases, there may be a term arbitrarily selected by the applicant, in which case the meaning thereof will be described in the description of the corresponding invention.

Therefore, it is intended that the terminology used herein should be interpreted based on the meaning of the term rather than on the name of the term, and on the entire contents of the specification.

Hereinafter, the RI (Receiver Initiated) -MAC protocol and the RC (Receiver Centric) -MAC protocol will be briefly described before explaining the CRI-MAC protocol proposed in this specification in detail.

Receiver Initiated (RI) MAC Protocol

First, the RI MAC Protocol method will be described.

As described above, the MAC protocol of the receiver-initiated method is advantageous in that the channel occupation time due to preamble sampling is eliminated and the throughput is improved in comparison with the Sender-Initiated MAC protocol method.

1 is a diagram illustrating an example of a receiver initiated MAC protocol method.

The RI-MAC protocol performs an idle listening operation until the transmitting node receives the beacon from the time when data is generated.

As used herein, a transmitting node may be expressed as a transmitting end, a sender, a transmitting device, a transmitter, or the like.

Thereafter, when the transmitting node receives a beacon from the receiving node, the transmitting node transmits data to the receiving node.

Thereafter, the transmitting node enters a sleep state. That is, the transmitting node maintains a sleep state during a sleep period after data transmission.

As we have seen, the disadvantage of the RI MAC Protocol method is that if the beacon period of the receiving node is long, the transmitting node will continue to idle listening to receive beacons that it does not know when it will receive, consuming unnecessarily energy.

Since the RI-MAC protocol method does not transmit the request message of the transmitting node, the transmitting node can not notify the surrounding node of the data to be transmitted, and receives the beacon message of the receiving node occurring in the next period I will wait until.

RI-MAC random Back off (random back-off)

Next, a random backoff method in the RI-MAC protocol will be described in detail.

2 is a diagram illustrating an example of a random backoff method in the RI-MAC protocol.

Whether or not a packet collision of the receiving node is detected due to packets transmitted from two or more transmitting nodes can be performed in the same manner as in FIG.

That is, although the receiving node can detect that a packet collision has occurred, the transmitting nodes that have caused packet collision can not know whether or not the transmitted packet has collided due to a packet transmitted by another transmitting node.

Here, regarding the detection of the packet collision of the receiving node, when the packets transmitted by the transmitting nodes partially overlap with the receiving node, the receiving node detects that the packet is collided.

When the receiving node detects a packet collision at a specific point in time, the receiving node broadcasts a collision notification beacon to notify that a packet collision has occurred.

As shown in FIG. 2, the reason why the receiving node does not send the collision notification beacon immediately after detecting the packet collision is to avoid collision with the (data) packet from the transmitting node, which may still remain.

Therefore, the transmitting node (s) receiving the collision notification beacon from the receiving node performs the random backoff and retransmits the packet to the receiving node.

That is, the collision avoidance method of RI-MAC is a method of retransmitting a packet after random backoff.

Therefore, the RI-MAC collision avoidance method is not a method of preventing or avoiding collision from the beginning, but there is a limitation in that it is a solution method after collision occurs.

RC (Receiver-Centric) -MAC protocol

Next, a receiver-centric (RC) MAC protocol method will be described.

The RC-MAC protocol method is the same as the RI-MAC protocol because it is a method for reducing packet collision.

However, the RC-MAC protocol differs from the RI-MAC in that it is a packet collision avoiding method that transmits packets while avoiding possible collisions from the beginning.

That is, the RC-MAC maintains a list of neighboring nodes located near the receiving node in order to transmit the packets without collision and schedules the packet transmission of the transmitting nodes using the list of neighboring nodes to solve the packet collision occurrence .

The RC-MAC is the same as the RI-MAC method in that the transmitting node having the data packet to be transmitted waits until it receives a beacon from the receiving node once it wakes up. However, the first data packet transmission process and the second data packet The transmission process is different.

(1) the first data packet transmission process

In the RI-MAC method, when the receiving node broadcasts a beacon, the transmitting node (a) that has awakened and waited receives a broadcast beacon and immediately transmits a data packet, thereby causing a collision. In order to avoid such a packet collision, each transmitting node transmits a packet after random backoff.

  In the first data packet transmission process, the shortest random backoff node transmits a data packet to the receiving node.

(2) the transmission process of the second data packet

The receiving node includes (or knows) the address of neighboring neighboring nodes.

As shown in FIG. 3, a sender B transmits data in a contention through a random back-off.

3 is a diagram illustrating an example of an RC-MAC protocol method.

Since the sender A (S (A)) and the sender C (S (C)) have not yet completed the random backoff, they overhear the data packet of the sender B (S (B)).

Thereafter, S (A) and S (C) overhearing the transmission packet of S (B) cancel the ongoing backoff and wait for the receiving node (or receiver) to schedule its packet transmission.

Here, the receiving node successfully receiving the data refers to the stored neighbor node list.

First, S (B) ends packet transmission, and S (C), which is the next order, corresponds to the next sequence of packet transmission.

In FIG. 3, a data transmission ACK beacon serves as an ACK packet for a transmitting node that previously transmitted data, and a transmitting node to which a packet is to be transmitted next.

Here, when the designated transmitting node does not hold the data to be transmitted from the beginning, it may happen that the data packet is not transmitted.

In Fig. 3, S (D) is a transmitting node corresponding to this case.

This occurs because the receiving node simply performs the scheduling with reference to the neighboring node list.

Therefore, the RC-MAC method proposes the following alternatives.

Since S (D) does not have a data packet to be transmitted from the beginning, S (D) does not transmit a packet even if the receiving node R designates S (D) as the next transmitting node to transmit data packets.

In this case, in order to prevent a situation in which no transmitting node transmits a data packet, another non-scheduled node S (A) performs retransmission after random backoff.

Also, in case that a transmitting node that is not scheduled or designated as S (A) performs retransmission after random backoff whenever it overrides an ACK beacon, in the case of retransmission, Transmits a data packet.

As we have seen, the RC-MAC method has a merit that the possibility of packet collision is significantly reduced compared with other methods because it is a method of scheduling one specific node by using a neighbor node list.

However, the RC-MAC has a limitation that all nodes must keep their own neighbor node list at all times and perform update continuously.

In the LPWAN, since the hardware limitations of the sensor node are large, there is a problem that when using the RC-MAC method, the size of the list of neighboring nodes held by each node increases, which leads to a large overhead.

In the RC-MAC method, if there is only one transmission node to transmit a data packet to the receiving node, transmission delay necessarily occurs because all transmitting nodes must perform a random back-off.

This delay occupies a significant portion of the transmission delay occurring in the RC-MAC method, and the larger the size of the backoff time slot, the more the transmission delay increases.

In addition, since the transmitting nodes frequently perform random backoff whenever the receiving node sends a beacon, the overhead of the node itself is large.

Low-Power Wide-Area Network: LPWAN )

Hereinafter, a brief description will be made of a low-power wide area network to which the presently proposed method can be applied.

LPWAN refers to a wireless wide area network with very low power consumption that provides a wide range of coverage over 10 km and a communication speed of up to several hundred kilobits per second (kbps) per second.

In addition, the low-power wide area network (LPWAN) is used as a dedicated Internet (IoT) network by providing a communication speed of several hundred bps to several hundred kbps per base station at a distance of about 10 km.

LPWAN is widely dispersed for water / gas / electric meter reading, bike theft prevention, asset management, etc., and the amount of data to be generated is very low, and the exchange frequency is low, Things to do are well suited for Internet devices and applications.

Techniques for realizing LPWAN include LTE-MTC (LTE Machine-Type Communications) using LoRaWAN, SIGFOX, etc. that use ISM license-free bands and narrow band objects And Internet (NB-IoT) technology.

CRI ( Collisionless  Receiver Initiated) -MAC Protocol

Hereinafter, the CRI-MAC protocol method proposed in the present specification will be described in detail with reference to related drawings.

The CRI-MAC protocol method proposed in this specification is a packet collision avoiding method which overcomes the disadvantages of the RI-MAC and RC-MAC methods discussed above.

The CRI-MAC method is a new scheduling method that prevents packet collision while lowering the overhead and allows the receiving node to receive packets from multiple transmitting node (s) without packet collision.

The CRI-MAC protocol method proposed in this specification can roughly be divided into (1) a scheduling method related to packet transmission / reception and (2) a packet collision avoiding method.

First, a scheduling method related to packet transmission / reception will be described.

CRI -MAC protocol packet Scheduling  Way

4 is a diagram illustrating an example of a packet scheduling method of the CRI-MAC protocol proposed in the present specification.

First, the transmitting node (s) having the packet to be transmitted transits to the wakeup state and transmits a sender competition (SC) beacon in the wakeup state.

The SC beacon may be transmitted in broadcast or unicast.

The SC (Sender Competition) beacon includes at least one of a DATA Length field indicating a length of data to be transmitted or a receive address field indicating an address of a receiving node to which the corresponding packet is to be transmitted.

Also, the SC beacon may include transmission node identifier information capable of identifying a transmission node.

Then, each transmitting node overheats an SC beacon transmitted from another transmitting node or a neighboring transmitting node, thereby determining a time for maintaining its own packet transmission time (or order or view) and a sleep state.

Here, a specific method by which each transmitting node determines a packet transmission order is determined as 'a value obtained by adding one to the number of overheated SC beacons'.

That is, if a transmitting node overhears two SC beacons, the packet transmission order of the corresponding transmitting node becomes '3'.

That is, the CRI-MAC scheduling method proposed in the present specification gives priority to packet transmission to the transmitting node that has transmitted the SC beacon late.

Through this, the transmitting nodes can know which transmission nodes are faster or slower than other transmitting nodes, and can know the packet transmission time of other transmitting nodes through the data length field included in the SC beacon.

Hereinafter, when receiving a receiver beacon from a receiving node, the transmitting nodes check their own packet transmission order or time point, transmit packets in the case of their own packet transmission order, , And operates in a sleep state until the transmission timing or sequence of the packet itself.

Here, the transmitting nodes may enter the sleep state at a time when the receiving node transmits a receiver beacon or when receiving a receiving beacon from the receiving node.

In addition, the transmitting nodes do not transmit a packet even when the packet is transmitted at the time of packet transmission, or transmit packets after a predetermined time to prevent collision with a packet transmitted immediately before.

That is, in the CRI-MAC scheduling method proposed in the present specification, transmission nodes transmit SC beacons and overhear SC beacons transmitted from other transmission nodes (s), thereby determining the packet transmission order or time point of each transmitting node do.

This is because the SC beacon includes a data length field indicating the data length to be transmitted by each transmitting node, as shown in FIG.

Therefore, if the transmission nodes are not in their own packet transmission order, the transmission nodes operate in a sleep state until the transmission of the other transmission node ends, thereby reducing power consumption.

A more detailed description will be given with reference to FIG.

Referring to FIG. 4, there are four nodes, Node A, Node C, and Node D are transmitting nodes, and Node B is a receiving node.

As shown in FIG. 4, since Node D is awake most late, Node D can not oversee any SC beacons transmitted from other competing transmission nodes.

Therefore, according to the foregoing, the packet transmission order of Node D is 1.

Since the Node A overhears (or receives) the SC beacons of the Node C and the Node D, the packet transmission order of the Node A becomes '2 + 1' three times.

Since the Node C overhears (or receives) only the SC beacon of the Node D, the packet transmission order of the Node C becomes '1 + 1' twice.

Therefore, Node A and Node C transition to the sleep state at the time when the Node B transmits the receiver beacon, and sleep state is maintained until the transmission time of each packet.

As described above, when using the CRI-MAC method, the transmitting nodes determine their packet transmission order based on the SC beacon, and transmit the packets according to the determined packet transmission order, thereby enabling the packet transmission without packet collision.

In addition, since a transmitting node such as a Node A having a wake up late transmission order maintains a sleep state for a data transmission time of a node (Node C and Node D) having a higher transmission order than the Node A, the power consumption is reduced .

CRI - How to resolve packet conflict in MAC protocol

Next, a method of resolving a packet conflict in the CRI-MAC Protocol will be described.

5 is a diagram illustrating an example of a packet conflict resolution method of the CRI-MAC Protocol proposed in the present specification.

In FIG. 5, Node A, Node C, and Node D are transmitting nodes, and Node B is a receiving node.

5, when the receiving node (Node B) detects a packet collision, the receiving node transmits a collision notification (CN) beacon 510 to inform the transmitting node (s) of occurrence of a packet collision, Lt; / RTI >

The CN beacon may be broadcast or unicast.

Here, the receiving node sets the scheduling for the transmitting node (s) in which the packet collision does not occur to take precedence over the scheduling for the transmitting nodes in which the packet collision occurs.

Therefore, as shown in FIG. 5, the receiving node preferentially receives the packet transmitted by the Node A in which no packet collision occurs.

The scheduling for the transmission nodes (Node C, Node D) in which the packet collision occurs is performed after the receiving node transmits the CN beacon again.

Therefore, the transmitting nodes (Node C and Node D) that caused the packet collision receive the CN beacon 510 from the receiving node, and then return to the listening state until the receiving node broadcasts the CN beacon 520 Wait.

At this time, the states of Node C and Node D are in the wakeup state.

As shown in FIG. 5, the transmitting nodes (Node C and Node D) receiving the second CN beacon from the receiving node perform a random backoff and transmit a request beacon 530 to the receiving node do.

The request beacon is a beacon for requesting a scheduling.

Then, the receiving node performs a scheduling for packet transmission of each transmitting node by transmitting a scheduling beacon 540 to the corresponding transmitting node in the order of receiving the request beacon from each transmitting node.

In FIG. 5, it can be seen that scheduling for Node C is performed, and then scheduling for Node D is performed.

As we have already seen, the Node D transmits a packet at a certain time after its transmission time to prevent collision with the packet transmitted by the Node C.

Thereafter, when the receiving node detects or recognizes that no packet is received from the transmitting nodes, the receiving node further broadcasts the receiving beacon 550 to check whether there is another transmitting node that has not participated in the competition .

If the receiving node determines that there is no additional transmitting node to which to transmit the packet, the receiving node waits for an additional node time (ANT, 560) and enters a sleep state.

6 is a flowchart illustrating an example of a scheduling method of the CRI-MAC protocol proposed in the present specification.

That is, FIG. 6 shows a method of transmitting and receiving a packet between nodes in a wireless communication system.

First, the transmitting node transitions to a wakeup state when a packet to be transmitted is generated.

Thereafter, the transmitting node transmits a sender competition (SC) beacon requesting scheduling of the packet to be transmitted in the wakeup state (S610).

Here, the SC beacon may include at least one of transmission node identifier information identifying the transmitting node, a data length field indicating a length of data to be transmitted by the transmitting node, and address information indicating an address of a receiving node to be transmitted by the transmitting node .

The transmitting node then overhears the SC beacon transmitted from at least one neighboring transmitting node in operation S620.

Thereafter, the transmitting node determines a transmission order of the packets based on the SC beacons (step S630).

Here, the transmission order of the packets is determined by adding 1 to the number of SC beacons.

Thereafter, the transmitting node receives a receiver beacon from the receiving node (S640).

Thereafter, the transmitting node determines whether the reception time of the receiver beacon is the transmission order of the determined packet (S650).

Thereafter, the transmitting node determines whether to transmit the packet according to the result of the check.

The transmitting node transmits the packet to be transmitted if the receiving beacon is the transmission order of the determined packet. If the receiving node does not receive the determined packet transmission order, And maintains a sleep state from the time of receiving the beacon until the transmission time of the determined packet.

Here, the hold time of the sleep state is determined based on the data length field included in the SC beacons.

7 is a flowchart showing an example of a packet collision avoiding method of the CRI-MAC protocol proposed in the present specification.

The procedures of FIG. 7 may be performed after the procedure of FIG. 6 or separately from the procedure of FIG.

Referring to FIG. 7, when the receiving node detects a collision of a packet transmitted by the transmitting nodes, the receiving node transmits a Collision Notification (CN) beacon indicating that a packet collision has occurred to the transmitting nodes S710).

After receiving the CN beacon, the receiving node receives a packet from a transmitting node that does not cause the collision of the packet.

Thereafter, the receiving node transmits the CN beacon to the transmitting nodes that caused the packet collision (S720).

Thereafter, the receiving node receives a request beacon requesting scheduling of packet transmission from the transmitting nodes that caused the packet collision (S730).

Thereafter, in step S740, the receiving node transmits a scheduling beacon that assigns scheduling to the transmitting nodes in the order in which the request beacons are received from the transmitting nodes that caused the collision.

Thereafter, the receiving node receives a packet from the transmitting nodes that caused the collision according to the order of the allocated scheduling (S750).

In addition, when the receiving node detects that a packet is not received from the transmitting nodes that have caused the collision, the receiving node transmits a receiving beacon for checking whether another transmitting node for transmitting the packet exists.

Thereafter, when the receiving node detects that the another transmitting node is not present, it transits to the sleep state after a predetermined time.

The CRI-MAC proposed in this specification can be designed for the ad-hoc communication between drones, and the communication module sharing the drone and the battery operates with low power, so that the drone flight time can be maximized.

In addition, the collision resolution method of the CRI-MAC protocol discussed above reduces the idle listening of the transmitting node compared to the conventional CS-MAC conflict resolution method, thereby preventing unnecessary power consumption.

The CRI-MAC protocol proposed in this specification maintains a distance of at least 1 Km and performs ad-hoc communication between drones, so that occurrence of a hidden node terminal becomes very rare.

The CRI-MAC is awakened first, but it has high power efficiency by compensating for the disadvantage of the CS-MAC method, which is wasted, but is assigned a higher sequence number, and sends data as late as that and wastes power.

Also, the CRI-MAC has a great advantage in that the power efficiency is very good as the number of nodes is larger than other MAC protocols.

Apparatus to which the present invention may be applied

8 illustrates a block diagram of a wireless communication apparatus according to an embodiment of the present invention.

Referring to FIG. 8, a wireless communication system includes a transmitting node 810 and a receiving node 820 located within a transmitting node region.

The transmitting node 810 includes a processor 811, a memory 812, and a radio frequency unit 813. The processor 811 implements the functions, processes and / or methods suggested in FIGS. 1-7 above. The layers of the air interface protocol may be implemented by the processor 811. The memory 812 is connected to the processor 811 and stores various information for driving the processor 811. [ The RF unit 813 is connected to the processor 811 to transmit and / or receive a radio signal.

The receiving node 820 includes a processor 821, a memory 822, and an RF section 823. The processor 1621 implements the functions, processes and / or methods suggested in Figures 1-7 above. The layers of the air interface protocol may be implemented by the processor 821. The memory 822 is coupled to the processor 821 to store various information for driving the processor 821. The RF unit 823 is connected to the processor 821 to transmit and / or receive a radio signal.

The memories 812 and 822 may be internal or external to the processors 811 and 821 and may be coupled to the processors 811 and 821 in various well known means.

In addition, the transmitting node 810 and / or the receiving node 820 may have a single antenna or multiple antennas.

The following is a specific operation in which the packet transmission / reception method proposed in this specification is performed through each hardware element of the transmitting node.

A transmitting node (or a transmitting apparatus or a transmitting node) for transmitting and receiving a packet in a wireless communication system,

An RF (Radio Frequency) unit for transmitting and receiving a radio signal; And

And a processor for controlling the RF unit,

Transits to a wakeup state when a packet to be transmitted occurs; A sender competition (SC) beacon requesting scheduling of the packet to be transmitted in the wakeup state, the SC beacon includes transmission node identifier information for identifying the transmission node, data to be transmitted by the transmission node A data length field indicating a length of a destination node, and address information indicating an address of a destination node to which the transmitting node wants to transmit; Overhearing an SC beacon transmitted from at least one neighboring transmitting node; The scrambler determines a transmission order of the packet based on the SC beacon, the transmission order of the packet is determined to be one plus the number of the SC beacons; Receiving a receiver beacon from the receiving node; Determining whether a time at which the receiver beacon is received is a transmission order of the determined packet; And transmitting the packet to be transmitted if the time at which the receiver beacon is received is a transmission order of the determined packet, in accordance with a result of the check, The sleep state is maintained from the reception of the receiver beacon until the transmission of the determined packet if the transmission order of the packet is not determined, Is determined based on the length field.

The receiving node may further include: an RF (Radio Frequency) unit for transmitting and receiving a radio signal; And a processor for controlling the RF unit, wherein when the processor of the receiving node detects a collision of a packet transmitted by the transmitting nodes, the processor of the receiving node notifies the transmitting nodes of a collision notification Collision Notification: CN); Receive a packet from a transmitting node that does not cause a collision of the packet after transmitting the CN beacon; Sending a CN beacon to the transmitting nodes that caused the packet to collide; Receiving a request beacon requesting scheduling of packet transmission from transmitting nodes that caused the packet to collide; Transmitting a scheduling beacon for assigning scheduling to the transmitting nodes in order of receiving the request beacon from the transmitting nodes that have caused the collision; And controls to receive a packet from the transmission nodes that caused the collision according to the order of the allocated scheduling.

If the processor of the receiving node detects that a packet is not received from the colliding transmitting nodes, the processor of the receiving node transmits a receiving beacon for checking whether another transmitting node for transmitting the packet exists or not; And to transition to a sleep state after a predetermined period of time when detecting that the other transmitting node is not present.

The embodiments described above are those in which the elements and features of the present invention are combined in a predetermined form. Each component or feature shall be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. It is also possible to construct embodiments of the present invention by combining some of the elements and / or features. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is clear that the claims that are not expressly cited in the claims may be combined to form an embodiment or be included in a new claim by an amendment after the application.

Embodiments in accordance with the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) field programmable gate arrays, processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, a procedure, a function, or the like which performs the functions or operations described above. The software code can be stored in memory and driven by the processor. The memory is located inside or outside the processor and can exchange data with the processor by various means already known.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. Accordingly, the foregoing detailed description is to be considered in all respects illustrative and not restrictive. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

510, 520: crash notification beacon
530: Request beacon
540: scheduling beacon
550: Recipient beacon

Claims (3)

A method for transmitting and receiving a packet in a wireless communication system, the method being performed by a transmitting node,
Transitioning to a wakeup state when a packet to be transmitted occurs;
Transmitting a Sender Competition (SC) beacon requesting scheduling of the packet to be transmitted in the wakeup state,
Wherein the SC beacon includes transmission node identifier information identifying the transmitting node, a data length field indicating a length of data to be transmitted by the transmitting node, and address information indicating an address of a receiving node to which the transmitting node wishes to transmit;
Overhearing an SC beacon transmitted from at least one neighboring transmitting node;
Determining a packet transmission order for how many packets are to be transmitted in relation to transmission packets of the at least one neighboring transmission node based on the SC beacons;
The packet transmission order is determined by adding 1 to the number of SC beacons; And
Determining whether to transmit the packet to be transmitted in consideration of a time of receiving the receiver beacon and a determined packet transmission order when receiving a receiver beacon from the receiving node,
And transmits the packet to be transmitted if the packet is to be transmitted at the time of receiving the receiver beacon,
Maintains a sleep state from a point of time at which the receiver beacon is received to a point at which the packet to be transmitted is transmitted when the receiver beacon is not in the order of transmitting the packet to be transmitted at the time of receiving the receiver beacon,
Wherein the hold time of the sleep state is determined based on a data length field included in the SC beacons. delete delete

Images