JP2003309571A - Radio lan system and packet transmission method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio LAN system capable of assuring real-time nature of sound packets. <P>SOLUTION: An access point 10 transmits beacons including CF (contention free) parameters to each radio LAN terminals 12, 14 in a predetermined period. If transmitted packets are sound packets, the LAN terminals 12, 14 store them temporarily into each sound buffer, and if the transmitted packets are data packets, the LAN terminals 12, 14 store them temporarily into each data buffer. The LAN terminals 12, 14 receive beacons transmitted from the access point 10 to calculate CFP (contention free period) and CP (contention period) periods based on the CF parameters included in the beacons, and transmit the sound packets stored in the sound buffers to the access point 10 during the CFP periods, and transmit the data packets stored in the data buffers to the access point 10 during the CP periods. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a wireless LAN (Local Ar
ea Network) system and packet transmission method, and in particular to a wireless LAN system and packet transmission method that guarantees real-time performance of voice packets.

[0002]

2. Description of the Related Art A wireless LAN is a LAN that uses radio waves as a transmission path.
Is basically an access point AP and multiple wireless LAs
It consists of N terminals STA (for example, STA1 and STA2), and is connected to the wired LAN by the above access point AP that performs wireless-wired medium conversion. The terminals STA1 and STA2 perform packet communication with other terminals STA and wired terminals of the wired LAN via the access point AP. This wireless LAN wireless access method includes a distributed consultation function (DCF: Distributed Coordi
nation function) method and point consultation function (PCF: Point C
There are two types of methods, but in either case, CSMA / CA with ACK is required to ensure communication quality.
(CSMA / CA: Carrier Sense Multiple Access with Coll
A method called "ion avoidance" is used to notify the sending side by an ACK packet that the receiving side has received the packet normally.

The packet transmission process by DCF will be described with reference to the time chart of FIG.
When trying to send a packet to the DCF interframe s
Access point AP and other terminals during pace (DIFS) period
Check whether the STA is using the wireless section.
Then, after confirming that the wireless section is not in use, the packet Data1 is transmitted to the access point AP. When the access point AP normally receives the packet Data1, the access point AP transmits to the terminal STA1 an ACK packet ACK1 indicating that the packet has been normally received within the short interframe space (SIFS) period. This completes the packet transmission process.

However, the access point AP
If Data1 cannot be received normally, then to terminal STA1
ACK Packet ACK1 is not sent. Terminal STA1 is a packet
After transmitting Data1, wait for ACK packet ACK1 from access point AP for a certain period of time. And within that fixed time
ACK When receiving ACK packet ACK1, access point AP
Ends the transmission process assuming that it normally received packet Data1 and does not receive ACK packet ACK1, it retransmits packet Data1 up to a fixed number of times until it receives ACK packet ACK1.

Next, FIG. 13 shows the packet transmission processing by the PCF.
Referring to the time chart of the above, when the access point AP starts polling, the PCF interframe
It is confirmed that the terminals STA1 and STA2 are not using the wireless section in the space (PIFS) period, and the polling packet P1 is transmitted to the first terminal STA1 at time t1 after the PIFS period.
At this time, the access point AP transmits a packet (P1 + D1) if there is a packet D1 to be transmitted to the terminal STA1.

When the terminal STA1 normally receives the packet (P1 + D1) from the access point AP, it transmits an ACK packet A1 to the access point AP within the SIFS period. At this time, if there is a packet U1 to be transmitted to the access point AP, the packet (A1 + U1) is transmitted. When the access point AP receives the packet (A1 + U1) normally, it
The ACK packet A1 is transmitted to the terminal STA1 during the FS period. At the time t2 when the access point AP finished polling, CF-E
It transmits the nd packet to notify the terminal STA1 that the polling period has ended.

[0007]

However, since the above-mentioned wireless LAN terminal does not have a function of distinguishing a voice packet and a data packet, when transmitting a voice packet and a data packet at the same time, the voice packet is prioritized. However, if the data packet is transmitted first, the voice packet cannot be transmitted until the data packet is completely transmitted.

Further, in the DCF access method,
In order to avoid transmission contention, back-off processing is used that waits for a random back-off time when other terminals are using the wireless section, so packet transmission is postponed and voice transmission is delayed. In some cases, real-time performance cannot be ensured. Therefore, in voice communication, it is common to use the PCF method that polls at regular intervals in order to guarantee real-time performance. However, with the PCF method, only one packet can be transmitted at one time, so
Voice packets cannot be sent until the next poll after the previous data packet has been sent.

Therefore, in the conventional wireless LAN system,
There is a problem that the real-time property of voice packets cannot be guaranteed.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a wireless LAN system and a packet transmission method capable of guaranteeing the real-time property of voice packets.

[0011]

In order to solve the above problems, the present invention provides points during a non-collision period of a collision period and a collision period in which an access point and a plurality of wireless LAN terminals are alternately repeated at a constant cycle. In a wireless LAN system that transmits / receives packets by the consultation function method and transmits / receives packets by the distributed consultation function method in the collision period, the access point transmits a beacon including information for calculating the non-collision period and the collision period at regular intervals, Multiple wireless LAN terminals receive the beacon transmitted from the access point, calculate the non-collision period and the collision period based on the information contained in the beacon, and transmit voice packets to the access point during the non-collision period to collide. In the period, the data packet is transmitted to the access point.

Further, according to the present invention, the access point and the plurality of wireless LAN terminals transmit and receive packets by the point consultation function method in the non-collision period of the collision period and the collision period in which the wireless LAN terminals are alternately repeated at a constant cycle, and in the collision period. In a packet transmission method for a wireless LAN system that transmits and receives packets by the distributed consultation function method, this method comprises a step of transmitting a beacon containing information for calculating a non-collision period and a collision period at a constant cycle by an access point, and a plurality of wireless The process of receiving the beacon transmitted from the access point by the LAN terminal and calculating the non-collision period and the collision period based on the information contained in the beacon, and the voice packet to the access point in the non-collision period calculated in this process. And transmitting data packets to the access point during the collision period. And wherein the Mukoto.

Further, the present invention is a wireless LAN terminal in a wireless LAN system for performing packet communication with an access point, which terminal temporarily stores a voice packet and a register for storing a packet type indicating a packet type. A voice buffer, a data buffer for temporarily storing data packets, a first counter for calculating the time of a non-collision period for transmitting and receiving packets by the point consultation function method based on set information, and a distributed consultation function method Second counter for calculating the time of the collision period for transmitting and receiving a packet based on the set information, means for storing the packet type in the register when the packet type is input from the outside, and the packet input from the outside The packet type based on the packet type stored in the register Means for storing the voice packet in the voice buffer and storing the data packet in the data buffer, and information for calculating the non-collision period by receiving a beacon including information for calculating the non-collision period and the collision period from the access point. A counter for setting the first counter and setting information for calculating the collision period in the second counter, and reading the voice packet from the voice buffer when the first counter indicates the non-collision period and transmitting the voice packet to the access point. Two
Means for reading out a data packet from the data buffer and transmitting the data packet to the access point when the counter indicates the collision period.

Furthermore, the present invention relates to a wireless LAN adapter in a wireless LAN system for transferring a packet from an access point to a wired LAN terminal and transferring a packet from the wired LAN terminal to the access point. Interface means for interfacing with, a register for storing a predetermined value, a voice buffer for temporarily storing a voice packet, a data buffer for temporarily storing a data packet, and a packet by the point consultation function method. A first counter for calculating a non-collision period for transmitting and receiving a packet based on the set information, and a second counter for calculating a collision period for transmitting and receiving a packet by the distributed consultation function method based on the set information
When the packet is input from the counter and the packet from the outside, if the input packet contains a tag and the value of the tag matches the value stored in the register, the packet is judged as a voice packet and stored in the voice buffer. If the input packet does not contain a tag, or if it contains a tag but the value of the tag does not match the value stored in the register, it is determined that the packet is a data packet and the means for storing it in the data buffer is accessed. The information for calculating the non-collision period is set in the first counter by receiving the beacon including the non-collision period and the information for calculating the collision period from the point, and the information for calculating the collision period is set in the second counter. Means and
Means for reading a voice packet from the voice buffer and transmitting it to the access point when the first counter indicates the non-collision period, and for reading the data packet from the data buffer and transmitting it to the access point when the second counter indicates the collision period. It is characterized by including.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a wireless LAN system according to the present invention will be described in detail with reference to the accompanying drawings. Figure 1
FIG. 1 is a configuration diagram showing a first embodiment of a wireless LAN system. This system consists of an access point 10 and wireless LAN terminals 12 and 14, and a wired LAN 16 is connected to the access point 10 that performs wireless-wired medium conversion, and wired terminals 18 and 20 are connected to the wired LAN 16 respectively. Has been done. This wireless LA
N system consists of access point 10 and wireless LAN terminal 12,
14 and the non-collision period (CFP: Co
ntention Free Period) and collision period (CP: Contentio
CFP of (n Period) sends and receives voice packets by PCF method, and CP sends and receives data packets by DCF method to guarantee the real-time property of voice packets.

The access point 10 periodically transmits the beacon B to the wireless terminals 12 and 14 as shown in FIG. 2, and information necessary for transmitting and receiving packets, for example, "Beac
Information such as "on interval", "TIM", and "CF Parameter Set" are periodically notified. Where Beacon int
erval indicates the interval between beacon frames transmitted by the access point 10, TIM indicates “DTIM Count” indicating the number of beacons until the next beacon, and “DTIM Period” indicating the DTIM interval.
d ”etc. are included. FIG. 2 is a diagram showing the relationship between the beacon B, DTIM, and DTIM Count when the DTIM Period is 3.
Count = 0 indicates that beacon B is DTIM. The access point 10 transmits a broadcast packet when transmitting the DTIM.

The CF Parameter Set is a CF (Contentio
n Free), and FIG. 3 shows an example of the format. Where "Element ID" is this parameter
The number indicating that it is a CF parameter, "Length" is
Length of CF parameter, "CFP Count" is the number of DTIM until the next CFP start time (CFP Count = 0 means the start of CFP), "CFP Period" is the number of DTIM of CFP interval,
“CFP Max Duration” is the time from the start of CFP to the end of CFP (the unit is TU defined in the wireless LAN standard), “CF
“P Dur Remaining” is the time from the present to the end of CFP (unit is TU).

FIG. 4 shows that the DTIM period is 3 beacons and CFP.
Period is 2DTIM, CFP MaxDuration is 2.5 beacon, CFP
When DurRemaining is 2 beacons, DTIM, beacon B, CFP Period, CFP MaxDuration, CFP DurRemainin
It is a figure which shows the relationship of g. In this embodiment, as will be described later, the CFP MaxDuration period of the CFP Period is used for the transmission of voice packets by the CFP method, and the other periods are used for the transmission of data packets by the CP method, respectively. Based on the above information contained in beacon B, the period for transmitting the voice packet and the period for transmitting the data packet are calculated.

FIG. 5 shows the wireless LAN terminals 12 and 14 in FIG.
It is a block diagram showing an example of. The SW unit 102 is an antenna changeover switch that switches the connection destination of the antenna 100, and is connected to the RF / IF unit 104. SW section 102 is RF
The RF signal output from the / IF unit 104 is output to the antenna 100, and the RF signal received by the antenna 100 is output to the RF / IF unit 104. The RF / IF unit 104 is a frequency converter that converts the frequency of the signal, and is connected to the BBP unit 106.
The RF / IF unit 104 converts the IF signal in the intermediate frequency band (for example, 300 MHz to 400 MHz) output from the BBP unit 106 into an RF signal in the radio frequency band (for example, 2.4 GHz band), and the SW unit 102. The RF signal output from the SW unit 102 is converted into an IF signal and output to the BBP unit 106.

The BBP unit 106 is a wireless LAN standard (IEEE802.1
1, a baseband processor including a modulation circuit and a demodulation circuit that performs coding and decoding in accordance with IEEE802.11b), and is connected to a MAC-A unit 108. The BBP unit 106, for example, encodes the radio frame output from the MAC-A unit 108 by spread spectrum, and then 300 MHz to 400 MHz.
The IF local signal in the Hz band is quadrature-modulated and output to the RF / IF unit 104. The IF signal output from the RF / IF unit 104 is converted to a baseband signal by the IF local signal and then decoded by spectrum despreading. The radio frame is taken out and output to the MAC-A unit 108.

The MAC-A unit 108 is a MAC in the OSI model.
A controller having a layer function and performing wireless access control according to a predetermined communication protocol. In this embodiment, the CF parameter and TIM included in the beacon transmitted from the access point 10 are used to calculate the CFP and CP times, and the CFP transmits the voice packet to the access point 10 by the PCF method, and the CP transmits the voice packet. Access point 10 data packet by DCF method
It has a function to send to. FIG. 6 is a block diagram showing an embodiment of the MAC-A unit 108.

The MAC-A unit 108 includes a control unit 200, a register 202, and counters 204 and 206. The control unit 200 is connected to the BBP 106 via a signal line 212 and an external device (eg, an external device) via a bus 214. , Personal computer CPU1
14) is connected to. The CPU 114 transmits / receives a packet between the control units 200 via the bus 214. When transmitting a packet, the CPU 114 outputs a packet identification indicating whether the packet is a voice packet or a data packet to the control unit 200. To do. Register 202, counters 204 and 206, and voice buffer 110 and data buffer 112 in FIG.
Are respectively connected to the control unit 200 via the bus 210.

The register 202 is a register for storing the above packet identification input from the CPU 114. Control unit 20
For example, 0 sets “1” in the register 202 when receiving a packet identification indicating a voice packet from the CPU 114, and sets “2” when receiving a packet identification indicating a data packet. When the control unit 200 receives a packet from the CPU 114, it determines the type of the received packet based on the packet identification stored in the register 202, and stores the voice packet in the voice buffer 110 and the data packet in the data buffer 112, respectively. To do.

The counters 204 and 206 are counters for calculating CFP and CP. In this embodiment, the access point 10
To Beacon that indicates the start of CFP (CFP Count = 0)
Is transmitted, the CFP Period included in the beacon
To counter 206 and CFP MaxDuration to counter 206. The counter 204 subtracts 1 from the count value each time DTIM (a beacon including a DTIM element) is received, and the counter 206 subtracts the count value by TU (unit defined by the wireless LAN standard). Also stops the subtraction when the count value reaches 0. In the control unit 200,
The counter value of the counter 204 can be used to know when the next CFP starts, and the counter value of the counter 206 can be used to know when the CFP is ended (when the CP is started).

The control unit 200 is a controller that executes wireless access according to a predetermined communication protocol, and in this embodiment, has a function of switching the packet transmission method to the PCF or DCF method according to CFP and CP. In particular,
In CFP, in response to polling from the access point, the voice packet stored in the voice buffer 110 is read out to generate a wireless LAN frame, and this is generated by the BBP unit 10
Output to 6. Further, the CP reads the data packet stored in the data buffer 112, generates a wireless LAN frame, and outputs this to the BBP unit 106.

The operation of the thus constructed wireless LAN system will be described with reference to the time chart of FIG. 7 and the flowchart of FIG.
Beacon B is periodically transmitted to terminals 12 and 14,
Then, the beacon B transmitted from the access point 10 is received. Also, in the control unit 200 of the MAC-A unit 108 in the terminals 12 and 14, when a packet is input from the CPU 114,
The type is judged based on the packet identification stored in the register 202, and the voice packet is stored in the voice buffer 110.
Then, the data packet is stored in the data buffer 112, respectively.

When the control unit 200 of the MAC-A unit 108 receives the beacon B indicating the start time of CFP, it extracts the CF parameter from the beacon frame and stores it in the counter 204.
The value of CFPPeriod and the value of CFP MaxDuration are set in the counter 206, respectively, and the packet transmission processing mode by the PCF method shown in FIG. 8A is entered. In counter 204, DTIM
Each time a beacon (DTIM) including an element is received, 1 is subtracted from the count value, and when the count value becomes 0, the subtraction is stopped. In the counter 206, the count value is
And the subtraction is stopped when the count value reaches 0.

At the access point 10, as shown in FIG. 7, after the beacon B is transmitted, the terminal is moved after the SIFS period has elapsed.
The polling packet P1 is transmitted to 12. When the polling packet P1 is received by the terminal 12, the MAC-A section
The control unit 200 of 108 confirms whether or not voice packets are accumulated in the voice buffer 110 (step S10 in FIG. 8 (a)). If voice packets are accumulated, this voice packet is read and Is transmitted to the access point 10 as a packet D1 (step S12). However, if no voice packet is stored in the voice buffer 110, a CF-ACK packet is transmitted to the access point 10 instead of the packet D1 (step S14).

Upon receiving the packet D1 from the terminal 12, the access point 10 sends an ACK (A1) to the terminal 12 and
Send packet (A1 + P2) including polling (P2) for 14. In the terminal 14, when receiving the polling (P2) from the access point 10, in the same manner as in the case of the terminal 12,
The voice packet is transmitted to the access point 10 as the packet D2. Upon receiving the packet D2 from the terminal 14, the access point 10 sends an ACK packet (A2) to the terminal 14.
To send. In this case, polling is completed for all terminals in the CFP, and when there is no transmission data for each terminal, the terminal is notified of ACK (A2) and the end of polling.
Send packet (A2 + CF-End) including CF-End.

When the count value of the counter 206 becomes 0, the control unit 200 judges that the CFP has ended, and switches from the packet transmission processing mode by the PCF method to the packet transmission processing mode by the DCF method, as shown in FIG. The packet is transmitted according to the processing flow shown in. Specifically, the control unit 200 confirms whether or not the data packet is stored in the data buffer 112 (step S20), and if the data packet is stored, the data packet is read and the wireless section is used. After confirming that it is not in the middle, the data is transmitted to the access point 10 (step S22).

In the control section 200, the packet transmission processing by the DCF method shown in FIG. 8B is repeatedly executed at a predetermined cycle until the count value of the counter 204 becomes 0, and the counter 20
When the count value of 4 becomes 0, it is judged that the CP period has ended, and the packet transmission processing by the DCF method is ended.
The terminals 12 and 14 repeatedly execute the voice packet transmission by the PCF method and the data packet transmission by the DCF method every CFP period. Therefore, CF the voice packet
It becomes possible to transmit every P period.

As described above, according to this embodiment, the wireless LAN
The terminals 12 and 14 temporarily store voice packets and data packets to be transmitted in separate buffers. The access point 10 transmits a beacon B including information for calculating CFP and CP to each terminal 12 and 14 at a constant cycle, and each terminal 12,
In 14, the CFP and CP are calculated from the information included in Beacon B.
It sends voice packets to CFP and data packets to CP. As a result, the voice packet can be transmitted at a constant cycle, and the real-time property of the voice packet can be secured. The packet transmission / reception method in this embodiment can be applied to an access point, a wireless LAN bridge, and the like.

FIG. 9 shows a second embodiment of the wireless LAN system according to the present invention. This system consists of an access point 10 and wireless LAN adapters 30 and 32.
Wired terminals 38 and 40 are connected to 30 and 32 via wired LANs 34 and 36. The adapters 30 and 32 wirelessly receive packets from the wired terminals 38 and 40 sent via the wired LANs 34 and 36.
The packet is converted into a packet suitable for LAN and transferred to the access point 10, and the packet from the access point 10 is converted into a packet suitable for wired LAN and transferred to the wired terminals 38 and 40. The same parts as those in FIG. 1 are designated by the same reference numerals.

FIG. 10 is a block diagram showing an embodiment of the adapters 30 and 32 described above. The adapters 30 and 32 are obtained by connecting the MAC-A unit 108 to the MAC-B unit 116 and the MAC-B unit 116 to the PHY unit 118 of the wireless LAN terminal shown in FIG.
A wired terminal is connected to the PHY unit 118 via a wired LAN. The PHY unit 118 corresponds to the physical layer in the OSI model and serves as an interface between a wireless LAN and a wired LAN. Also, the MAC-B section 116 is the MA in the OSI model.
It corresponds to layer C, and interfaces between wireless LAN and wired LAN. In FIG. 8, the same parts as those in FIG. 1 are designated by the same reference numerals.

FIG. 11 shows the adapters 30 and 32 and a wired terminal.
It is a configuration example of a frame transmitted and received between 38 and 40,
(a) is an Un-Tag that does not include commonly used tags (TAG)
Frame, (b) is a tag conforming to IEEE802.1Q including TAG
It is a frame. In this embodiment, when transmitting voice packets from the wired terminals 38, 40 to the adapters 30, 32, the
Use g-frames and use either Un-Tag or Tag frames when sending data packets. However, the TAG value of the Tag frame used for audio packets is predetermined and shall be different from the TAG value of the Tag frame used for data packets.

In the present embodiment, the register 202 of the MAC-A unit 108 in the adapters 30 and 32 stores the same value as the TAG of the Tag frame used for the voice packet in advance. Further, the control unit 200 has a function of detecting whether or not a TAG is included in the frame when the packet is received from the MAC-B unit 116, and the TA if the frame includes the TAG.
A function that compares the value of G with the value stored in register 202, and if a match is found, the packet is considered as a voice packet and is temporarily stored in voice buffer 110. If there is no match and TAG is not included In this case, the data buffer 112 has a function of temporarily judging that the packet is a data packet.

The operation of the wireless LAN system according to this embodiment will be described. For example, when the packet transmitted from the wired terminal 38 is input to the adapter 30, the PHY unit 118 of the adapter 30 is input.
Then, the input packet is converted into an electric signal that can be processed by the MAC-B unit 116 and output to the MAC-B unit 116. MAC-B part 11
In 6, when a frame (packet) is received from the PHY unit 118, an error check is performed using the FCS (frame check sequence) of that frame, and if it is an error frame, it is discarded. If it is a normal frame, P (preamble) is removed. Transfer to MAC-A section 108.

When the MAC-A unit 108 receives a frame from the MAC-B unit 116, it determines whether the frame contains a TAG, and if the frame contains a TAG, the TA
Compare the value in G with the value stored in register 202. When the TAG value and the value stored in the register 202 match, the frame received from the MAC-B unit 116 is determined to be a voice packet and temporarily stored in the voice buffer 110. However, the frame received from MAC-B section 116
If TAG is not included, or if TAG is included but the TAG value does not match the value stored in register 202, the frame received from MAC-B section 116 is judged as a data packet and is stored in data buffer 112. Accumulate temporarily.

In the MAC-A unit 108, the voice packet stored in the voice buffer 110 is sent to the address pointer 10 in response to the polling from the access pointer 10 in the CFP, as in the case of the embodiment shown in FIG. The CP transmits the data packet to the address pointer 10 when the CP stores the data packet in the data buffer 112.

As described above, according to the embodiment, the wired terminal 38,
In 40, when sending voice packets to adapters 30 and 32, a frame containing a TAG with a predetermined value is used, and in adapters 30 and 32, voice packets and data packets are sent based on this TAG value. The data is stored in separate buffers, the voice packet is sent to the CFP to the access pointer 10, and the data packet is sent to the CP. It becomes possible to secure. The packet transmission / reception method in this embodiment can also be applied to an access point and a wireless LAN bridge.

[0041]

According to the wireless LAN system of the present invention, at the access point, there is a constant cycle of non-collision period (CFP).
And a beacon including information on the collision period (CP) to each wireless LAN terminal, and the wireless LAN terminal uses the CFP and CFP based on this information.
Since the CP is calculated and the CFP transmits the voice packet and the CP transmits the data packet, the real-time property of the voice packet can be secured.

Further, according to the wireless LAN system of the present invention, the wired terminal transmits the voice packet to the wireless LAN adapter by using the frame containing the TAG of a predetermined value,
The LAN adapter distinguishes voice packets from data packets based on this TAG value, CFP sends voice packets, and CP sends data packets.
It is possible to secure real-time property even for voice packets from N terminals.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a wireless LAN system according to the present invention.

FIG. 2 is a diagram showing a relationship between a beacon transmitted from an access point and DTIM in the wireless LAN system shown in FIG.

FIG. 3 is a diagram showing a format of a CF parameter included in a beacon transmitted from an access point of the wireless LAN system shown in FIG.

4 is a diagram showing the relationship between beacons, DTIMs, and CFPs transmitted from access points in the wireless LAN system shown in FIG.

5 is a wireless LAN in the wireless LAN system shown in FIG.
It is a block diagram which shows the Example of a terminal.

6 is a block diagram showing an embodiment of a MAC-A unit in the wireless LAN terminal shown in FIG.

FIG. 7 is a time chart showing packet transmission / reception timings in the wireless LAN system shown in FIG.

8 is a flowchart showing the operation of the wireless LAN terminal shown in FIG. 5, where (a) is a packet transmission process in CFP,
(b) shows the packet transmission process in CP.

FIG. 9 is a configuration diagram showing a second embodiment of the wireless LAN system according to the present invention.

10 is a wireless LA in the wireless LAN system shown in FIG.
It is a block diagram showing an example of an N adapter.

11 is a configuration diagram of a frame transmitted from the wired terminal shown in FIG. 9 to a wireless LAN adapter, (a) is an Un-Tag frame configuration diagram, and (b) is a Tag frame configuration diagram.

FIG. 12 is a time chart of packet transmission / reception by DCF.

FIG. 13 is a time chart of packet transmission / reception by PCF.

[Explanation of symbols]

10 access points 12, 14 Wireless LAN terminal 30, 32 Wireless LAN adapter 38, 40 Wired terminal 102 SW section 104 RF / IF section 106 BBP Department 108 MAC-A section 110 voice buffer 112 data buffer 116 MAC-B section 118 PHY section

Claims (4)

[Claims] 1. A point consultation function method is used to transmit and receive packets during a non-collision period between a collision period and a collision period in which an access point and a plurality of wireless LAN terminals are alternately repeated at regular intervals, and a distributed consultation function is performed during the collision period. In the wireless LAN system for transmitting and receiving packets by the method, the access point transmits a beacon including information for calculating the non-collision period and the collision period at the fixed cycle, and the plurality of wireless LAN terminals are A beacon transmitted is received, a non-collision period and a collision period are calculated based on the information included in the beacon, a voice packet is transmitted to the access point in the non-collision period, and a data packet is transmitted in the collision period. A wireless LAN system characterized by transmitting to an access point. 2. A point-negotiation function method is used to transmit and receive packets during the non-collision period in which the access point and a plurality of wireless LAN terminals are alternately repeated at regular intervals, and the non-collision period in the collision period. A method for transmitting a packet in a wireless LAN system for transmitting and receiving a packet according to a method, the method comprising: transmitting a beacon including information for calculating the non-collision period and the collision period by the access point at the constant cycle; A step of receiving a beacon transmitted from the access point by the wireless LAN terminal and calculating a non-collision period and a collision period based on the information included in the beacon; and a voice packet in the non-collision period calculated in the step. To the access point, and during the collision period, data packets are sent to the access point. And a packet transmitting method in a wireless LAN system. 3. A wireless LAN terminal in a wireless LAN system that performs packet communication with an access point, the terminal comprising: a register for storing a packet type indicating a packet type; an audio buffer for temporarily storing an audio packet; A data buffer for temporarily storing data packets and a time for a collision-free period in which packets are transmitted and received by the point consultation function method are calculated based on set information.
Counter, a second counter for calculating the time of the collision period for transmitting and receiving packets by the distributed consultation function method based on the set information, and storing the packet type in the register when the packet type is input from the outside Means for determining the type of the packet when the packet is input from the outside based on the packet type stored in the register, and storing the voice packet in the voice buffer and the data packet in the data buffer, respectively. And setting the information for calculating the non-collision period in the first counter by receiving the beacon including the non-collision period and the information for calculating the collision period from the access point, and setting the information for calculating the collision period in the second counter. Means for setting to the counter of the voice buffer, And a means for reading a packet and transmitting the packet to the access point, and reading the data packet from the data buffer and transmitting the packet to the access point when the second counter indicates a collision period. Wireless LAN terminal. 4. Wired packets from an access point
Wireless in a wireless LAN system that transfers to a LAN terminal and transfers packets from a wired LAN terminal to an access point
In the LAN adapter, the adapter includes interface means for interfacing with the wired LAN terminal, a register for storing a predetermined value, a voice buffer for temporarily storing a voice packet, and a data packet for a temporary period. A data buffer to store, a first counter that calculates the non-collision period for sending and receiving packets by the point consultation function method, and information that sets the collision period for transmitting and receiving packets by the distributed consultation function method When a packet is input from the outside and the input packet includes a tag and the value of the tag matches the value stored in the register, the packet is input based on the second counter It is judged as a voice packet and stored in the voice buffer, and the input packet contains a tag. And a tag is included but the value of the tag does not match the value stored in the register, means for judging the packet as a data packet and storing it in the data buffer, and a non-collision period from the access point. And means for setting information for calculating a non-collision period by receiving a beacon including information for calculating a collision period in the first counter and setting information for calculating a collision period in the second counter, When the first counter indicates a non-collision period, the voice packet is read from the voice buffer and transmitted to the access point, and when the second counter indicates the collision period, the data packet is read from the data buffer and the access point. A wireless LAN adapter in a wireless LAN system, which comprises: