KR20040076125A - Wireless lan data frame, method and system for transmitting and receiving of wireless data using the same - Google Patents

Abstract

PURPOSE: A wireless LAN data frame and a wireless LAN data transmitting/receiving method and system using the same are provided to reduce power consumption by enabling station devices to receive only MAC header information, not the whole frame including a frame body region. CONSTITUTION: A MAC header includes 2-byte frame check field, 2-byte duration ID field, the first to third address fields each having 6 bytes, 2-byte sequence control field, the fourth address field of 6 bytes, and 4-byte of header frame check sequence field. The first address field defines a basic service set, the second address field defines a destination address, the third address field defines a source address, the sequence control field defines a fragment number and a sequence number, and the fourth address field defines a transmission/reception address. The header frame check sequence field is generated by a CRC(Cyclic Redundancy Check) algorithm to check the availability of the MAC header frame.

Description

WIRELESS LAN DATA FRAME, METHOD AND SYSTEM FOR TRANSMITTING AND RECEIVING OF WIRELESS DATA USING THE SAME}

The present invention relates to a WLAN data frame, a method and system for transmitting / receiving WLAN data using the same, and more particularly, to a WLAN data frame for reducing power consumption of a WLAN data system, and to using the same. It relates to a transmission / reception method and a system thereof.

Today, many commercial personal computers are connected by local area networks (LANs). Each personal computer user can freely access the Internet via a LAN and exchange data between computers. However, existing wired LAN users can enjoy various functions of LAN only through cabling that requires limited space and high installation cost.

In recent years, many users use computers by directly connecting to a network in a mobile work environment in real time. If a user in a mobile workplace requires information from a central database or needs an Internet connection, a wired LAN environment must use a docking station such as a hub connected to a wired network.

However, in wireless LANs, mobile work stations can be directly connected to servers or other devices on the network, such as access points, and can be used in many places such as universities, warehouses, ports, factories, and retail businesses. It is already using a wireless LAN transmission / reception system adopting various wireless LAN solutions.

When the access point apparatus and the destination station apparatus of the wireless LAN transmit / receive system perform continuous data transmission / reception for a long time, the remaining station apparatuses except the destination station apparatus may transmit / receive data regardless of their own. Continuously reads the Duration ID from the data frames transmitted / received between the destination station device and the access point device to enter a backoff for transmission, and uses a Network Allocation Vector. The operation of updating the NAV) value is continued. In this case, the remaining station devices must validate the received WLAN data frame and update the NAV value.

In order to update the NAV value, the entire wireless LAN data frame must be received, even if it is irrelevant to itself, and the CRC check must be performed through the FCS, which is the last information of the wireless LAN data frame.

Moreover, if the data frame body to be transmitted / received is long, it is cumbersome to take longer to receive all of the irrelevant parts only for the CRC check. For example, if the data frame body is 1500 bytes, the data required by another station device needs to be received only for 4 [㎲] corresponding to 24 bytes of the data frame header part. If you receive, you will receive unnecessary data for 224 [㎲].

Therefore, in the other station devices except the destination station device, as the length of the data frame body becomes longer, only unused data should be read for data frame validation, and power consumption increases accordingly.

Accordingly, the present invention has been made in an effort to solve such a conventional problem, and an object of the present invention is to provide a WLAN data frame for reducing power consumption by providing separate FCS information for validating a data frame header portion. To provide.

Another object of the present invention is to provide a method of transmitting / receiving WLAN data for inserting and transmitting the aforementioned separate FCS information into a WLAN data frame.

Further, another object of the present invention is to provide a WLAN data transmission / reception system suitable for performing the above-described WLAN data transmission / reception method.

1 is a view for explaining a wireless LAN data transmission / reception system.

2 is a view for explaining the station apparatus of FIG.

3 is a view for explaining a channel contention of the wireless LAN data transmission / reception system according to the present invention.

4 is a diagram for explaining NAV value setting according to the present invention.

5 is a diagram for explaining an RTS frame.

6 is a diagram for explaining a CTS frame.

7 is a view for explaining an example of a wireless LAN data frame according to the present invention.

8 is a diagram for explaining an ACK frame.

9 is a flowchart for briefly explaining the operation of the access point apparatus according to the present invention.

10 is a flowchart for briefly explaining the operation of the station apparatus according to the present invention.

11 is a view for explaining another example of a WLAN data frame according to the present invention.

12 is a view for explaining another example of a WLAN data frame according to the present invention.

<Description of the symbols for the main parts of the drawings>

AP: access point device STA1 STA2, STA3: station device

212: receiving unit 214: sending unit

216: central processing unit 218: timer

In accordance with one aspect of the present invention, a WLAN data frame includes a MAC header having a frame check field, a duration field, a plurality of address fields, and a sequence control field; A first frame check sequence field for validating the MAC header; A variable length frame body disposed at a rear end of the MAC header and containing information defining the frame type; And a second frame check sequence disposed at a rear end of the frame body to verify the validity of the MAC header and the frame body.

In addition, the wireless LAN data transmission / reception method according to one feature for realizing the above object of the present invention, the wireless LAN data for transmitting and receiving data through the channel setting with any one of a plurality of station devices In a transmission / reception method, (a) transmitting an RTS frame; (b) checking whether to receive a CTS frame indicating that transmission is possible without collision in response to the RTS frame; And (c) as the CTS frame is received in step (b), transmitting a data frame through channel setting with the CTS frame transmitter, and verifying the validity of the MAC header in the MAC header of the data frame. And including the header frame check sequence for transmission.

In addition, a wireless LAN data transmission / reception system according to one feature for realizing another object of the present invention, a wireless LAN for transmitting / receiving data through channel setting with any one of a plurality of station devices In the data transmission / reception system, an RTS frame is generated and transmitted, and upon receiving a CTS frame indicating that transmission is possible without collision in response to the RTS frame from one of the plurality of station devices, And an access point apparatus for transmitting a data frame through channel setting, including a header frame check sequence for validating the MAC header in the MAC header of the data frame.

In addition, a wireless LAN data transmission / reception method according to another feature for realizing another object of the present invention, a wireless LAN data transmission / reception method for transmitting / receiving data through a channel setting with an access point apparatus (A) receiving an RTS frame provided from the access point apparatus and checking whether a destination address included in the RTS frame is the same as its own address; (b) transmitting a CTS frame indicating that transmission is possible without collision in response to the RTS frame when the destination address and its address are the same in step (a); (c) receiving a data frame corresponding to the CTS frame and transmitting an ACK frame; (d) setting a NAV value corresponding to the RTS frame based on a duration value included in the RTS frame when the destination address and its own address are different in step (a); (f) updating the NAV value based on a duration value included in the CTS frame; (g) receiving the MAC header of the data frame to validate the MAC header; (h) if the validity of the MAC header is verified in step (g), updating the NAV value based on a duration value included in the MAC header; And (i) updating the NAV value based on a duration value included in the ACK frame.

In addition, a wireless LAN data transmission / reception system according to another feature for realizing another object of the present invention described above is a wireless LAN data transmission / reception for transmitting / receiving data through a channel setting with an access point apparatus. In the system, upon receiving the RTS frame provided from the access point apparatus, if the destination address included in the RTS frame and its own address are the same, the system generates a CTS frame indicating that transmission is possible without collision in response to the RTS frame. A destination station apparatus configured to transmit, receive a data frame corresponding to the CTS frame, and generate and transmit an ACK frame; And setting a NAV value corresponding to the RTS frame according to the reception of the RTS frame, updating the NAV value according to the reception of the CTS frame, and only the header of the data frame according to the reception of the data frame. And the remaining station apparatus for receiving and updating the NAV value.

In addition, a wireless LAN data transmission / reception method according to another aspect for realizing the above object of the present invention is to transmit / receive data through the channel setting between the access point device and the access point device; A method of transmitting / receiving wireless LAN data including a plurality of station devices, the method comprising: (a) transmitting an RTS frame at the access point device; (b) setting a NAV value based on a duration field included in the RTS frame for each of the remaining station devices except the destination station device among the plurality of station devices that have received the RTS frame; (c) the destination station apparatus having a first period of time, transmitting a CTS frame; (d) when the CTS frame is received, each of the remaining station devices except the destination station device updates the NAV value based on a duration field included in the CTS frame; (e) the access point device receiving the CTS frame having a second period of time, transmitting a data frame; And (f) the station apparatus receiving the data frame has a third period of time, transmitting an ACK frame.

In addition, the wireless LAN data transmission / reception system according to another aspect for realizing the above object of the present invention, by generating a RTS frame having the address of the destination station device set through a channel contention process and wireless transmission And a CTS frame indicating that transmission is possible without collision in response to the RTS frame and transmitting data through channel setting with the CTS frame transmitting side; A destination station apparatus for transmitting the CTS frame, receiving a data frame corresponding to the RTS frame, and generating and transmitting an ACK frame corresponding to normal reception according to the reception of the RTS frame; And setting a NAV value corresponding to the RTS frame according to the reception of the RTS frame, updating the NAV value according to the reception of the CTS frame, and only the header of the data frame according to the reception of the data frame. And the remaining station apparatus for receiving and updating the NAV value.

According to such a WLAN data frame and a method and system for transmitting / receiving WLAN data using the same, additional header FCS information for validating only a frame header part is provided separately from the FCS information for validating the entire frame. By inserting, other station devices independent of the transmit / receive channel in the WLAN MAC protocol can reduce power consumption by updating the NAV value without receiving the entire frame including the frame body area.

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

1 is a view for explaining a wireless LAN data transmission / reception system, Figure 2 is a view for explaining the station apparatus of FIG.

Referring to FIG. 1, a basic service set (BSS) constituting a wireless LAN data transmission / reception system includes data through a wireless channel setting between one access point device (AP) and the access point device (AP). It includes three station devices (STA1 STA2, STA3) for transmitting / receiving. The AP may wirelessly transmit or wirelessly transmit WLAN data, and the station apparatus may wirelessly transmit or wirelessly transmit WLAN data.

For example, the first station apparatus 210 may include an antenna ANT, a reception unit 212, a transmission unit 214, a central processing unit 216, and a timer 218 to operate the antenna ANT. The wireless LAN data may be received via the antenna, or the wireless LAN data may be transmitted through the antenna ANT.

In operation, when the first station device STA1, which is a channel set destination station device and the access point device AP, performs a continuous data transmission / reception operation for a long time, the remaining station devices STA2 and STA3 continuously operate. Reads the Duration ID from various frames transmitted / received between the first station device STA1 and the access point device AP and updates a Network Allocation Vector (NAV) value. Continue operation. This is because even if the data is transmitted / received irrelevant to itself, it is always required to enter the backoff for the transmission / reception. In this case, the remaining station devices STA2 and STA3 must verify the validity of the received WLAN data frame and update the NAV value.

As such, in the WLAN data transmission / reception system, the WLAN standard stipulates channel contention to prevent collisions that may occur in a competitive channel acquisition process, and the standard timer value used for the standard is NAV. Value.

The NAV value informs network members through the duration / ID field in the header information of the sender. It is preferable that the range of the said NAV value is 0-32767 [kV].

The NAV value of each station device is set and updated when each frame is received, and decreases by 1 every second. If the NAV value is not 0, it is determined that another station device is using a channel. If the NAV value is 0, channel competition operation is performed with other station devices.

Next, the channel contention scheme defined in the WLAN data transmission / reception system will be described first, and then the NAV value setting for data transmission will be described.

3 is a view for explaining a channel contention of the wireless LAN data transmission / reception system according to the present invention.

Referring to FIG. 3, one of the first station apparatuses transmits a data frame to an access point apparatus (AP), and the AP ACK frame transmits an AP ACK frame in response thereto.

At the time when the transmission of the ACK frame sent by the access point device (AP) is completed, that is, at point "A", each station device will have its own NAV value set to zero and start full channel competition. The channel competition section is divided into four sections (SIFS, PIFS, DIFS, and Contention Window). Each IFS (Inter Frame Space) is a section existing between each frame and is a section for giving priority to a specific frame before entering the overall channel competition.

For example, when the SIFS needs to transmit a CTS frame or an ACK frame, the SIFS transmits a frame immediately after a time equivalent to that SIFS (16 [ms] in the IEEE 802.11a standard) passes. Therefore, it has priority over other transmission frames because it transmits preferentially without going to the entire channel contention interval.

The PIFS is used when the access point device (AP) sends a specific control frame, and in the case of transmission of a general data frame, a contention window is performed through a contention window after the DIFS time. .

Of course, since the lengths of the SIFS, PIFS, and DIFS are different for each standard of the WLAN data transmission / reception system, absolute values are meaningless, and only relative interval lengths exist for priority.

The contention window is composed of subsections called slot time, and the absolute value of each slot time is defined as 9 [ms] in IEEE 802.11a and 20 [ms] in IEEE 802.11b.

Upon entering the contention window after the DIFS, each station device wishing to acquire a channel generates a random back off value between 0 and 255, for example. In the drawing, the first station apparatus STA1 generates 8, the second station apparatus STA2 generates 10, and the third station apparatus STA3 generates 14 as the random backoff value.

As a result, since the first station apparatus STA1 has generated a random backoff value that is relatively smaller than the second station apparatus STA2 or the third station apparatus STA3, the first station apparatus after the eighth slot time has passed. STA1 acquires a wireless LAN data transmission / reception channel and transmits a frame prepared by itself, preferably a CTS frame. The CTS frame is a signal indicating that transmission is possible without collision in response to the RTS frame transmitted from the AP.

As soon as the first station device STA1 transmits the CTS frame, the second station device STA2 or the third station device STA3 detects that the channel is busy and stops the backoff operation. It enters a receive operation and uses the remaining back off value to participate in subsequent channel contention opportunities.

In other words, the second station device STA2 or the third station device STA3 waits for the NAV value to be zero for transmission of its frame, preferably the CTS frame, and if each is zero, each priority When the channel is in the idle state while the back off value elapses in the contention window after the IFS interval, the CTS frame is transmitted.

As such, each station apparatus can generate a random back off value, so that the channel usage is operated fairly, and collisions can be prevented.

In the above, it was confirmed that in order to follow the channel contention rule defined in the WLAN data communication standard, the NAV value should be read and set and updated from all frames transmitted in the BSS.

Then, the rule describes how to set and update the NAV value, and what operations are performed by the access point apparatus (AP) or the station apparatus.

4 is a view for explaining the NAV value setting according to the present invention, Figure 5 is a view for explaining the RTS frame, Figure 6 is a view for explaining the CTS frame, Figure 7 is a wireless LAN according to the present invention FIG. 8 illustrates an example of a data frame, and FIG. 8 illustrates an ACK frame.

In FIG. 4, the access point device AP first acquires a channel through channel contention, and transmits an RTS frame indicating that there is data to be sent to the first station device STA1. After the SIFS, the first station apparatus STA1 responds with a CTS frame, and again, the first data frame DATA1, the first acknowledgment frame ACK1, the second data frame DATA2, and the second acknowledgment frame ACK2. Suppose that they are transmitted at SIFS intervals and finally enter channel competition again.

First, the AP 100 configures and transmits an RTS frame as shown in FIG. 5 to acquire a channel through channel contention after DIFS. Specifically, the RTS frame includes a 2-byte frame check field, a 2-byte duration field, a 6-byte receiving side address field RA (here, the address of the first station apparatus STA1), and a 6-byte transmitting side. An address field TA (herein, an address of an access point apparatus AP) and a 4-byte frame check sequence (FCS) field for determining validity of the corresponding frame are included.

That is, the receiver receives a CTS frame and a receiving side address (here STA1) to transmit, records the time required to receive the acknowledgment frame (ACK) after sending the first data frame (DATA1) and transmits it. In FIG. 4, the time required from A to D is calculated, recorded in the duration field, and transmitted.

Subsequently, the AP 100 waits for a CTS frame to be received after wirelessly transmitting the RTS frame, and if the CTS frame is received, transmits the first data frame DATA1 to which it wants to transmit after SIFS. Wireless transmission. If the data to be transmitted by the access point device AP ends in the first data frame DATA1, the required time from point C to point D is calculated and described in the duration field.

However, when there is more data to be transmitted by the AP 100 itself, that is, when the second data frame DATA2 is present, a second Ack frame corresponding to the second data frame DATA2 ( ACK2) and the time to come, that is, the time required from point C to F, are calculated and described in the duration field and transmitted.

When the last acknowledgment (ACK) is entered, all the operations are terminated and the channel race is entered again. If the data frame is transmitted but no acknowledgment (ACK) is received, the receiver determines that it has not been properly received and retransmits it. The retransmission operation is also preferably transmitted after acquiring a channel through channel contention.

In the above description, it has been described that the RTS frame is transmitted before the data frame is transmitted after acquiring the channel for WLAN data transmission / reception. However, the data frame may be immediately transmitted without the transmission of the RTS frame. However, the RTS is used for secure transmission because a frame that is initially transmitted due to a hidden node problem has the highest probability of collision. Of course, a rule for transmitting the RTS frame may be arbitrarily determined by each vendor.

The transmission of the RTS frame is to reduce the probability of collision even if it takes a little longer than the time lost by the collision by transmitting the long data frame immediately. The RTS frame may not be transmitted only by the AP, but may also be transmitted by a station device.

Meanwhile, in the destination station device 210, the first station device STA1, which fails to acquire a channel in the first channel contention, is in a reception mode and receives an RTS frame from the access point device AP. That is, after confirming that the RA field included in the RTS frame is its own address, the first station device STA1 generates a CTS frame as shown in FIG. 6 and wirelessly transmits it after SIFS. Specifically, the CTS frame includes a 2-byte frame check field, a 2-byte duration field, a 6-byte receiving side address field RA (in this case, an address of an access point device AP), and a validity determination of the corresponding frame. Frame check sequence (FCS) field.

Of course, when the CTS frame is generated, the duration value is calculated and described in the CTS frame. Specifically, the duration value received from the RTS frame is obtained by subtracting the time required for transmitting the CTS frame and the length of one SIFS, that is, the time required from B to D as the duration value.

After the CTS frame is transmitted by the destination station device 210, the data station DATA is received from the access point device AP after the SIFS period, and the first station device STA1 that has received the data has passed the SIFS. After that, an ACK frame is generated and transmitted.

As illustrated in FIG. 7, the data frame DATA includes a 34-byte Medium Access Control (MAC) header defined by the IEEE 802.11 standard, a frame body varying from 0 to 2312 bytes, and a 4-byte frame. Contains a check sequence.

Specifically, the MAC header includes two frame check fields, two byte duration ID fields, six byte first to third address fields, two byte sequence control fields, six byte fourth address fields, and four byte bytes. Contains a header frame check sequence field. Here, the first address field defines a basic service set (BSS), the second address field defines a destination address, the third address field defines a source address, and the sequence control field is a fragment. A fragment number and a sequence number are defined, and the fourth address field defines a transmission / reception address. In addition, the header frame check sequence (Header FCS) field is generated by a cyclic redundancy check (CRC) algorithm having 4 bytes and is a field for checking the validity of the MAC header frame, which is the same value as the frame check sequence. .

The frame body has a variable length of 0 to 2312 bytes, is disposed at the rear of the MAC header to embed substantial data, and the frame check sequence (FCS) is composed of 4 bytes to form a CRC field generated by the CRC algorithm. Built.

On the other hand, as shown in Fig. 8, the ACK frame includes a frame check field of 2 bytes, a duration field of 2 bytes, and a receiving side address field RA of 6 bytes (here, the address of the access point device AP). And a 4-byte frame check sequence (FCS) field for determining validity of the frame. The acknowledgment frame (ACK) is identical to the configuration of the CTS frame. This is because both the acknowledgment frame (ACK) and the CTS frame are intended to inform that the message transmitted by the transmitter is well received.

The calculation of the duration value is the same as the calculation of the duration value included in the CTS frame, the value obtained by subtracting the time required to transmit the Ack frame ACK from the duration value received from the first data frame DATA1 and one SIFS length. That is, the time required from point D to F is transmitted.

After receiving the second data frame DATA2 and transmitting the last second acknowledgment frame ACK2 after SIFS, the duration value received from the second data frame DATA2, that is, the required time from E to F Subtracting the time required to transmit an ACK and the SIFS time results in zero.

Therefore, after transmitting the last second acknowledgment frame (ACK2), all the station devices in the BSS enters the channel contention state.

On the other hand, the remaining station devices (STA2, STA3) 220, 230 except for the destination station device (STA1) 210 enter the reception mode by failing the first channel contention, and the RTS frame transmitted by the access point device (AP) Receive.

Then, since the address of the destination station apparatus STA1 is described in the RA included in the RTS frame, it can be confirmed that the address of the destination station apparatus STA1 is not the address of the remaining station apparatus. Accordingly, only the duration value is updated. The duration value is decreased by 1 every ㎲, and the duration value becomes 0 and only waits to enter the channel competition again.

If the duration value is not 0 before entering the channel contention, it is continuously in the reception mode, and each time a new RTS frame is received, the RA included in the new RTS frame is checked.

In addition, since the duration field exists in the MAC header in the first data frame DATA1 transmitted from the access point device AP, the duration value of the first data frame DATA1 is continuously based on the duration value included in the first data frame DATA1. Update At this time, even if the FCS information present in the tag field of the first data frame DATA1 is not checked to determine whether the first data frame DATA1 is valid, the header FCS information present in the tag field of the MAC header is determined. If it is checked that the validity of the first data frame DATA1 is valid, the duration value of the first data frame DATA1 is updated.

Lastly, when the second acknowledgment frame (ACK2) is received, the duration value is 0. Therefore, when the reception of the second acknowledgment frame (ACK2) is completed, the device enters a channel race immediately after the DIFS period.

9 is a flowchart for briefly explaining the operation of the access point apparatus according to the present invention.

Referring to FIG. 9, an access point apparatus (AP), which has acquired a channel through initial channel competition, transmits an RTS frame as shown in FIG. 5 (S110).

Then, it is provided from the station apparatus, and it is checked whether or not to receive the CTS frame as shown in FIG. 6 (step S120), and when the CTS frame is received, the header FCS is included in the data frame and the data according to the present invention. After generating the frame (step S130), the generated data frame is transmitted (step S140). The generated data frame is as shown in FIG.

Subsequently, it is checked whether the ACK frame as shown in FIG. 8 is received (step S150), and if the ACK frame is received, it is checked whether a residual data frame exists (step S160).

If the residual data frame exists in step S160, the header FCS is included in the residual data frame to generate a data frame according to the present invention (step S170). The generated data frame is as shown in FIG.

Subsequently, the generated data frame is transmitted and then fed back to step S150 (step S180).

On the other hand, if it is checked in step S160 that the remaining data frame does not exist, a channel race state is entered (step S190).

10 is a flowchart for briefly explaining the operation of the station apparatus according to the present invention.

Referring to FIG. 10, it is checked whether or not to receive an RTS frame provided from an access point apparatus (AP) (step S205). If it is checked that the RTS frame is the same, it is checked whether the destination address including the RTS frame is the same as its own address (step S210).

If it is checked in step S210 that the destination address and its own address are the same, a CTS frame is transmitted (step S215).

Subsequently, it is checked whether or not the data frame provided from the access point apparatus AP is received (step S220). If the data frame is received, an ACK frame is transmitted and then fed back to step S220 (step S225).

On the other hand, when it is checked in step S210 that the destination address and its own address are different, the NAV value is set based on the RTS (step S230), and it is checked whether the CTS frame provided from the access point device AP is received ( Step 235S).

When the CTS frame is received in step S235, the NAV value is updated based on the CTS frame (step S240).

Subsequently, it is checked whether or not the data frame provided from the access point apparatus AP is received (step S245). When the data frame is received, the NAV value is updated based on the data frame (step S250).

Then, it is checked whether the ACK frame is received (step S255), and if it is checked that the ACK frame is received, the NAV value is updated based on the ACK frame (step S260).

After updating the NAV value by the step S260 or when the data frame is not received in the step S220, it is checked whether the NAV value is 0 (step S265), and the NAV value is checked by zero. If it is determined that the channel contention state is entered (step S270), and if it is checked that the NAV value is not 0, it feeds back to step S245.

As described above, according to the present invention, by additionally inserting an FCS for validating the frame header in the frame header, the remaining station devices are provided with header information in the entire data frame unless the received data frames come to themselves. Since only duration information is required, power consumption can be reduced by decoding only the MAC header even without decoding the frame body region for validating the data frame.

For example, approximately 220 [mW] is required to transmit a data frame having a frame body of 1,500 bytes. However, according to the present invention, since only about 8 [㎲] is needed to receive the duration information, the power required for reception can be reduced by continuing the reception operation for frame validity verification for the remaining 200 [㎲] time.

In the above description, the header frame check sequence field is provided at the rear of the MAC header to check the validity of the WLAN data frame. However, as shown in FIG. 9, the header may be arranged in the middle of the MAC header.

11 is a view for explaining another example of a WLAN data frame according to the present invention.

Referring to FIG. 11, another example of the WLAN data frame according to the present invention includes a MAC header of 34 bytes, a frame body varying in size from 0 to 2312 bytes, a frame check sequence of 4 bytes, and a MAC header. Is a 2-byte frame check field, 2-byte duration field, 6-byte first address field, 4-byte header frame check sequence field, 6-byte second and third address fields, 2-byte sequence control field, And a fourth address field of six bytes. In particular, the header frame check sequence field consists of 4 bytes and is a field for checking the validity of the MAC header frame, which is the same value as the frame check sequence.

The frame body has a variable length of 0 to 2312 bytes, is disposed after the MAC header to embed substantial data, and the frame check sequence (FCS) consists of 4 bytes to embed a CRC field.

In this way, a header frame check sequence (Header FCS) field is provided after the first address ADD1, which is the destination address, so that another station apparatus that does not perform data transmission / reception with the access point apparatus AP is updated by updating the NAV value. Power consumption can be reduced.

On the other hand, as shown in Figure 12 to check the validity of the WLAN data frame may be arranged at the front end of the frame body.

12 is a view for explaining another example of a WLAN data frame according to the present invention.

Referring to FIG. 12, another example of the WLAN data frame according to the present invention includes a 30-byte MAC header, a 4-byte header frame check sequence, a frame body varying in size from 0 to 2312 bytes, and 4 bytes. And a MAC header includes a frame check field of two bytes, a duration field of two bytes, a first to third address field of six bytes, a sequence control field of two bytes, and a fourth address field of six bytes, respectively. It includes.

The header frame check sequence field of 4 bytes is provided after the MAC header, and the frame body and frame check sequence is provided after the header frame check sequence field. In this case, the header frame check sequence field is a field for checking the validity of the MAC header frame and has the same value as the frame check sequence.

Of course, the remaining station devices receiving the WLAN data frame according to another example of the present invention are based on the header frame check sequence received after receiving the MAC header including the duration value and before receiving the frame body. The operation of checking the validity of the MAC header will be performed.

The power consumption increases when decoding the duration value using the data frame of FIG. 7 or the duration value updating using the data frame of FIG. 11, but does not need to receive the FCS disposed behind the frame body. Can be reduced.

As described above, according to the present invention, in addition to the FCS information for validating the entire frame, additional header FCS information for validating only the frame header part in the entire frame is inserted into the frame, and thus, the WLAN MAC protocol. Regardless of the frame transmitted / received at, the station apparatuses may reduce power consumption by updating the NAV value by receiving only the MAC header instead of receiving the entire frame including the frame body region.

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the present invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

As described above, according to the present invention, the station devices not related to the data frame transmitted / received in the WLAN data transmission / reception system do not receive the entire frame including the frame body area, but receive only the MAC header information, thereby providing the frame. Modem processing operations for receiving and decoding body regions can be eliminated, thereby reducing power consumption.

In addition, although the advantage of the wireless LAN is mobility, it has not been easy to use for a long time in the absence of electricity because the power consumption is large, according to the present invention even if the operation of receiving and decoding the entire frame of the WLAN data frame Since only the frame check sequence included in the header of the WLAN data is received, power consumption can be reduced, and thus the standby time can be extended even when the same battery is used.

Claims (20)

A MAC header having a frame check field, a duration field, a plurality of address fields, and a sequence control field; A first frame check sequence field for validating the MAC header; A variable length frame body disposed at a rear end of the MAC header and containing information defining the frame type; And And a second frame check sequence disposed at a rear end of the frame body to validate the MAC header and the frame body. The WLAN data frame according to claim 1, wherein the first frame check sequence field is the same as the second frame check sequence. The WLAN data frame as claimed in claim 1, wherein the first frame check sequence field is generated by a CRC algorithm. The apparatus of claim 1, wherein the MAC header comprises: a frame check field, a duration ID field disposed after the frame check field, first to third address fields sequentially disposed after the duration ID field, Defined by a sequence control field disposed after the third address field, a fourth address field disposed after the sequence control field, and the first frame check sequence field disposed after the fourth address field. Featuring a WiFi data frame. The apparatus of claim 1, wherein the MAC header comprises: a frame check field, a duration ID field disposed after the frame check field, first to third address fields sequentially disposed after the duration ID field, A sequence control field disposed after the third address field and a fourth address field disposed after the sequence control field; The first frame check sequence field is disposed between the first address field and the second address field. The apparatus of claim 1, wherein the MAC header comprises: a frame check field, a duration ID field disposed after the frame check field, first to third address fields sequentially disposed after the duration ID field, Defined by a sequence control field disposed after the third address field and a fourth address field disposed after the sequence control field, The first frame check sequence field is disposed between the MAC header and the frame body. In a wireless LAN data transmission / reception method for transmitting / receiving data through channel setting with any one of a plurality of station devices, (a) transmitting an RTS frame; (b) checking whether to receive a CTS frame indicating that transmission is possible without collision in response to the RTS frame; And (c) As the CTS frame is received in the step (b), the data frame is transmitted through channel setting with the CTS frame transmitter, and the MAC header of the data frame is used to verify the validity of the MAC header. And transmitting and including the header frame check sequence. The method of claim 7, wherein (d) checking whether an ACK frame indicating normal reception of the data frame is received; (e) checking whether there is at least one remaining data frame different from the data frame as the ACK frame is received in step (d); (f) if the residual data frame exists in step (e), transmitting a header frame check sequence for validating the MAC header of the residual data frame in the MAC header of the residual data frame; And (g) if the remaining data frame does not exist in step (e), further comprising: establishing a channel with any one of the plurality of station apparatuses through channel contention. Receive method. The method of claim 7, wherein the data frame, MAC header; A variable length frame body disposed at a rear end of the MAC header and containing information defining the frame type; And Disposed at a rear end of the frame body, the second frame check sequence for validating the MAC header and the frame body; And the header frame check sequence is provided in the MAC header to verify the validity of the MAC header. The method of claim 7, wherein the data frame, MAC header; A variable length frame body disposed at a rear end of the MAC header and containing information defining the frame type; And Disposed at a rear end of the frame body, the second frame check sequence for validating the MAC header and the frame body; The header frame check sequence is a WLAN data transmission / reception method, characterized in that arranged in the rear end of the MAC header to verify the validity. In a wireless LAN data transmission / reception system for transmitting / receiving data through channel setting with any one of a plurality of station devices, Generates and transmits an RTS frame, and receives a CTS frame indicating that transmission is possible without collision in response to the RTS frame from any one of the plurality of station apparatuses. Send it, And an access point apparatus including and transmitting a header frame check sequence for validating the MAC header in the MAC header of the data frame. In a wireless LAN data transmission / reception method for transmitting / receiving data through channel setting with an access point device, (a) receiving an RTS frame provided from the access point apparatus and checking whether a destination address included in the RTS frame is identical to its own address; (b) transmitting a CTS frame indicating that transmission is possible without collision in response to the RTS frame when the destination address and its address are the same in step (a); (c) receiving a data frame corresponding to the CTS frame and transmitting an ACK frame; (d) setting a NAV value corresponding to the RTS frame based on a duration value included in the RTS frame when the destination address and its own address are different in step (a); (f) updating the NAV value based on a duration value included in the CTS frame; (g) receiving the MAC header of the data frame to validate the MAC header; (h) if the validity of the MAC header is verified in step (g), updating the NAV value based on a duration value included in the MAC header; And (i) updating the NAV value based on a duration value included in the ACK frame. The method of claim 12, wherein the data frame, MAC header; A variable length frame body disposed at a rear end of the MAC header and containing information defining the frame type; And Disposed at a rear end of the frame body, the second frame check sequence for validating the MAC header and the frame body; And the header frame check sequence is provided in the MAC header to verify the validity of the MAC header. The method of claim 12, wherein the data frame, MAC header; A variable length frame body disposed at a rear end of the MAC header and containing information defining the frame type; And Disposed at a rear end of the frame body, the second frame check sequence for validating the MAC header and the frame body; The header frame check sequence is a WLAN data transmission / reception method, characterized in that arranged in the rear end of the MAC header to verify the validity. In a wireless LAN data transmission / reception system that transmits / receives data through channel setting with an access point device, In response to receiving the RTS frame provided from the access point device, when the destination address included in the RTS frame and its own address are the same, a CTS frame indicating that transmission is possible without collision in response to the RTS frame is generated and transmitted. A destination station apparatus for receiving a data frame corresponding to the CTS frame and generating and transmitting an ACK frame; And In response to the reception of the RTS frame, a NAV value is set corresponding to the RTS frame, the NAV value is updated according to the reception of the CTS frame, and only the header of the data frame is received in response to the reception of the data frame. And a remaining station device for updating the NAV value. In a wireless LAN data transmission / reception method for transmitting / receiving wireless LAN data, including an access point apparatus and a plurality of station apparatuses for transmitting / receiving data through channel setting with the access point apparatus, (a) transmitting an RTS frame at the access point device; (b) setting a NAV value based on a duration field included in the RTS frame for each of the remaining station devices except the destination station device among the plurality of station devices that have received the RTS frame; (c) the destination station apparatus having a first period of time, transmitting a CTS frame; (d) when the CTS frame is received, each of the remaining station devices except the destination station device updates the NAV value based on a duration field included in the CTS frame; (e) the access point device receiving the CTS frame having a second period of time, transmitting a data frame; And and (f) the station apparatus having received the data frame has a third period of time, and transmitting an ACK frame. The method of claim 16, wherein the data frame, MAC header; A variable length frame body disposed at a rear end of the MAC header and containing information defining the frame type; And Disposed at a rear end of the frame body, the second frame check sequence for validating the MAC header and the frame body; And the header frame check sequence is provided in the MAC header to verify the validity of the MAC header. The method of claim 16, wherein the data frame, MAC header; A variable length frame body disposed at a rear end of the MAC header and containing information defining the frame type; And Disposed at a rear end of the frame body, the second frame check sequence for validating the MAC header and the frame body; The header frame check sequence is a WLAN data transmission / reception method, characterized in that arranged in the rear end of the MAC header to verify the validity. The RTS frame having the address of the destination station apparatus set through the channel contention process is generated and wirelessly transmitted, and the CTS frame transmitting side and the channel setting are received according to the reception of the CTS frame indicating that transmission is possible without collision in response to the RTS frame. An access point device for transmitting data via; A destination station apparatus for transmitting the CTS frame, receiving a data frame corresponding to the RTS frame, and generating and transmitting an ACK frame corresponding to normal reception according to the reception of the RTS frame; And In response to the reception of the RTS frame, a NAV value is set corresponding to the RTS frame, the NAV value is updated according to the reception of the CTS frame, and only the header of the data frame is received in response to the reception of the data frame. And a remaining station device for updating the NAV value. 20. The WLAN data transmission / reception system according to claim 19, wherein the remaining station device further updates the NAV value corresponding to the ACK frame according to the reception of the ACK frame.