JPH0637763A - Radio communication system - Google Patents

Abstract

PURPOSE:To avoid a state of increase of traffic uselessly by implementing reception processing when it is discriminated that optionally received information is information communicated in its own group. CONSTITUTION:When radio terminal equipments 1b, 1e receive a packet, the packet is discriminated to be valid through the collation of a zone identifier, and other packet is sent to a personal computer 2b and a bridge 4a via digital interfaces 3b, 3e respectively. Even when radio terminal equipments 1c, 1d, 1f receive the packet, the packet is discriminated to be invalid through the collation of a zone identifier and the radio terminal equipments 1c, 1e do not send other packet to the personal computer 2b and the bridge 4a. Moreover, the bridge 4a uses a bridge function to discriminate a DA of the precedence packet is that for an information terminal equipment in its own zone and no packet is sent to a wired LAN (local area network) 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a LAN (Local Area Network) which uses radio as a communication means of a plurality of information terminal devices classified into a plurality of zones.

[0002]

2. Description of the Related Art A LAN (Local Area Network) using a cable (such as a coaxial cable) is often used for an information transmission system such as a premises. In such a wired LAN, a wireless LAN is strongly required because it takes time and cost to re-install when a layout change or the like occurs from the initial installation state. In particular,
In Japan, the IEEE802.3 standard 10 Mbps CSMA / is widely used as a wired LAN.
CD (Carrier Sense Multiple Access with Collision
The standardization work of the method ensuring the compatibility with the detection method is in progress.

In realizing this wireless LAN,
The following three communication modes are possible. First, the access control system and the information transmission system are both performed in a distributed manner (hereinafter, referred to as “equal distribution system”), secondly, both are performed in a centralized manner, and thirdly, access control is performed in a centralized manner and information transmission is performed. The system is a distributed method. Among them, the equal distribution method is most suitable for the design concept of LAN because wireless terminals can directly communicate with each other in the control / transmission system. It is not necessary to prepare a central station, and therefore it is easy to introduce even if the number of wireless terminals is small. Since there is no centralized station, the whole system does not go down, the centralized station does not need to fold back the signal, so the required bandwidth can be minimized, no special work such as centralized station installation is required, and like a wired LAN It has many advantages such as no need to register IDs at central stations. On the other hand, it has a drawback that an access control function such as collision detection is required in all terminals.

By the way, in the wireless communication, assuming that the output of the radio wave is below a predetermined value, the range within which the radio wave can reach is limited. Therefore, direct communication is performed with a radio terminal outside a certain range. I can't. Therefore, the area where the wireless terminals exist is divided into multiple zones, and the wireless terminals in each zone are configured to enable direct communication, and each zone has a bridge connected to another wired network or wireless network. A method of providing one or more of the above is adopted. At this time, the wireless terminals in the same zone communicate directly with each other, and the wireless terminals in different zones wirelessly connect to the bridges in the zone and another wired network or wireless network between the bridges. Communicate.

When a plurality of zones are provided in this way, it is necessary to prevent radio communication within a zone from adversely affecting communication within other zones. Therefore, for example, in a car telephone, the zone is formed as a regular hexagon, the frequency bands used are changed in adjacent zones, and the same frequency is repeatedly used in zones separated by a certain distance or more that do not affect each other. I am trying to use it.

However, if the available frequency band is limited, the distance between the zones cannot be sufficiently set, or in the extreme case, the same frequency band is used in adjacent zones. In the case where a plurality of zones are provided in the above-described equal distributed wireless LAN system, if the frequency band is limited, the following problems occur.

First, when a wireless terminal transmits a packet addressed to a wireless terminal in another zone, and the destination wireless terminal can directly receive the packet wirelessly, the packet is bridged in the zone of the transmitting side. Since the data is transmitted via the wired network or the wireless network connected to, the same packet will reach the destination wireless terminal twice. Furthermore, if a packet sent by a wireless terminal is correctly received by a bridge in another zone, the packet will be sent to the wired network or wireless network connected to that bridge, which is similar to the above problem. Then, the same packet will arrive multiple times at the destination wireless terminal.
Therefore, there arises a problem that the traffic is unnecessarily increased.

The fact that a packet sent by a certain wireless terminal can be correctly received by the bridges of several different zones causes each bridge to erroneously register that the wireless terminal is included in its own zone. In other words, it is not possible to correctly determine whether the packet communicated by each wireless terminal is a wireless terminal in the same group (zone or wireless LAN system independent of each other) or a wireless terminal in a different group. The point is the fundamental problem.

[0009]

As described above, when constructing an evenly distributed wireless LAN system, in order to operate the system sufficiently even if the frequency band is restricted, it is necessary for each wireless terminal to operate. Communicating packets are in the same group (zone or wireless LA independent of each other)
It is an important issue to be able to correctly determine whether the wireless terminals in the N system) communicate or the wireless terminals in different groups communicate.

[0010]

In order to achieve the above object, the present invention provides a plurality of information communication terminals which are classified into a plurality of groups, and at least the communication between the information communication terminals which are classified into the same group. In a wireless communication system using a wireless communication unit, the wireless communication unit receives and transmits the arbitrary information by wireless communication between the information communication terminals classified into the same group. The control means includes a determination means for determining whether or not the arbitrary information is information to be communicated within its own group, and a control means for performing a predetermined communication process based on the determination result by the determination means, wherein the control means is A receiving process is performed when a result of determination that the arbitrary information received by the communication unit is information to be communicated within its own group is obtained from the determination unit. To provide a signal system.

[0011]

According to the present invention, the control means performs the receiving process when it obtains the determination result that the arbitrary information received by the communication means is the information to be communicated within its own group. The wireless communication means does not confuse arbitrary information communicated by the wireless communication means of the other group and arbitrary information communicated by the wireless terminal means of its own group, and traffic is unnecessarily increased. The situation can be avoided.

[0012]

First, a first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a configuration example of a wireless LAN system of the equal distribution system to which the present invention is applied. 7a,
Reference numerals 7b, 7c, 7d, 7e, 7f and 7g are wireless terminals, and various information terminal devices such as data terminals such as personal computers and workstations, voice terminals, image terminals, etc. are connected to these wireless terminals through digital interfaces. By doing so, it becomes possible to wirelessly communicate with each other. Wireless terminals in different zones, such as 7a in zone 6a and 7f in zone 6b, communicate using the same frequency but do not communicate directly by radio but are connected to bridges 4a, 4b. It communicates via the wireless terminals 7d and 7e and the wired LAN 5. FIG. 2 is a diagram illustrating a configuration example of a wireless terminal.

First, the case of transmission will be described. The transmission data (user information) input from the various information terminal devices to the wireless terminal via the digital interface is first transferred to the I / F.
The unit 10 performs level conversion, frame synchronization, speed conversion, and the like. Subsequently, the packet configuration unit 11 adds a field unique to the wireless unit (for example, a packet identifier described later), and the scramble unit 12 scrambles the data to randomize it. After that, the coding unit 13 performs coding for error correction and error detection and adds a collision detection field generated by the collision detection unit 20 to obtain the user information frame structure shown in FIG. 3B. After being input to the modulation unit 14 and subjected to modulation, for example, four-phase PSK modulation, the RF unit 40 converts the RF frequency f1 and outputs from the antenna 41.

For the control packet transmitted from the terminals connected to the bridges 4a and 4b, the control unit 21 writes the packet identifier, the transmission station address, the target station address, and the control information in the packet configuration unit 11, and the packet configuration unit 11 Outputs these data in the order shown in FIG. 3 (1). After scrambling these data in the scramble unit 12, the coding unit 13 performs coding for error correction and error detection, and adds a collision detection field generated by the collision detection unit 20 to FIG. As shown in the control frame structure, each of the control frames is input to the modulation unit 14 to be modulated, and then is converted into an RF frequency f1 by the RF unit 40 and output from the antenna 41.

RF frequency f input from the antenna 41
The signal of No. 1 is level-compensated, frequency converted, and
After band limitation and the like, it is input to the demodulation unit 34. Demodulator 3
4, carrier synchronization, demodulation (for example, 4-phase PSK demodulation),
Clock synchronization (clock reproduction), carrier detection,
The carrier detection signal, demodulation clock, and demodulation data are sent to the decoding unit 33. Further, the carrier detection signal is sent to the collision detection unit 20. Here, the carrier detection signal means the RF unit 40.
Is a signal that is 1 when the level of the signal input to the demodulation unit 34 in the designated frequency band is equal to or higher than a specified value, and is 0 when the level is less than the specified value.

The data output from the demodulation unit 34 is subjected to error correction and error detection in the decoding unit 33, descrambling in the descrambling unit 32, and then the packet decomposing unit 31.
The packet identifier is checked at. In the case of the user information packet, since the target station address to the error detection additional bit are the same as the frame structure on the AUI interface (FIG. 4 (1)), the I / F is used as it is.
It is sent to various information terminal devices via the unit 30. In the case of a control packet, the control unit 21 reads the content.

Next, an example of the frame structure of each packet will be described with reference to FIGS. 3 and 4. For example, when an IEEE802.3 AUI interface is considered as an interface with various information terminal devices, the frame structure on the interface is as shown in FIG. 4 (1).

On the other hand, there are two types of frame configurations for transmission on the wireless section, for example, two types shown in FIGS. 3 (1) and 3 (2), and (1) is for control for use in the time division zone multiplexing system proposed by the present invention. The frame structure of the packet is shown, and (2) shows the frame structure of the user information packet for transferring the user information transferred between the AUI interface and various information terminal devices. The two types of packets are distinguished by the packet identifier, and the control packet (FIG. 3 (1)) includes the control information field and the user information packet (FIG. 3).
(2)) includes a user information length and a user information field. Also, collision detection field, preamble, frame start delimiter, target station address, transmission station address,
The error detection additional bit and the error correction additional bit are common to the two types of packets. User information packet (Fig. 3
In (2)), the frame structure on the AUI interface from the target station address to the additional bits for error detection (see FIG. 4).
It is the same as (1)). Further, each component of the frame will be described in detail below.

The collision detection field is a field added by the collision detection unit 20 in FIG. 2, and is proposed in Japanese Patent Application No. 3-151876 in order to realize CSMA / CD in a wireless LAN of the even distribution system. This is for detecting a collision in a wireless section, such as the "random pulse collision detection method". A detailed description of this collision detection field will be given later.

The preambles of (1) and (2) of FIG. 3 are signals for the demodulation unit 34 of the receiving-side wireless terminal to establish carrier synchronization and bit synchronization. The frame start delimiter is used by the receiving wireless terminal for packet synchronization. The transmission station address and the destination station address are the addresses (48 bits) of various information terminal devices connected to the wireless terminals on the transmitting side and the receiving side, and are the same addresses as those in FIG. 4 (1) transferred by the AUI interface.

Next, the communication timing of the wireless terminal in each zone will be described with reference to FIGS. In FIG. 5 (1), "transmission permission packet" and "communication prohibition packet" are transmitted as control packets from the wireless terminals connected to the bridges 4a and 4b to notify the communication timing to the terminals in the zone. The case is shown.

In FIG. 1, the wireless terminal 7d connected to the bridge of the zone 6a transmits a transmission permission packet with transmission permission "0" and zone number "6a" in the control information field shown in FIG. 3 (1). When the wireless terminals (7a, 7b, 7c) in the zone 6a receive this, the packet disassembling unit 31 shown in FIG.
Cancels the transmission prohibition and enables transmission from the wireless terminal.
In order for the wireless terminal to perform transmission, the so-called CSMA /
The access protocol of the CD is used.

After a lapse of a certain time T from the permission of transmission, the wireless terminal 7d connected to the bridge 4a receives the data shown in FIG.
"Transmission prohibition packet" with transmission prohibition "1" and zone number "6a" in the control information field shown in (1)
Wireless terminal 7a, 7b, 7c in the zone 6a receives this, and is checked by the packet disassembling unit 31 like the transmission permission packet, and the control unit 21 controls the wireless terminal 7a, 7b, 7c.
Transmission from 7b and 7c is prohibited.

The wireless terminal 7d connected to the bridge 4a transmits the transmission prohibition packet and then prohibits transmission in its own zone by using the user information field of the packet shown in FIG. The wireless terminal 7e connected to the bridge 6b is notified via the wired LAN 5. The wireless terminal 7e connected to the bridge 4b of the zone 6b, which has received this notification, transmits the transmission permission packet to allocate the communication time in the zone 6b. Thereafter, this operation is repeated between the zones to be multiplexed at the same frequency.

By the way, in the present invention, since the wireless access is a random access which can be transmitted from the wireless terminal at any time in the zone where the communication is permitted, the transmission from the wireless terminals 7a, 7b, 7c is performed as shown in FIG. 5 (2). It is conceivable that the packet (user information packet) and the transmission prohibition packet (control packet) from the wireless terminal 7d connected to the bridge may collide. Therefore, the wireless terminal connected to the bridge must also perform transmission by the CSMA / CD access protocol and wait until the transmission line is empty before transmitting. However, if the traffic in the zone is high,
The user information packet and the control packet may collide. Therefore, only when transmitting the control packet, the wireless terminals 7d, 7 connected to the bridge are connected.
After detecting the transmission path empty, e is subjected to priority control so that the control packet can be transmitted with priority over other general wireless terminals.

FIG. 5C shows a method of controlling the communication timing using only the communication permission packet. The wireless terminal 7d connected to the bridge of the zone 6a is shown in FIG.
As shown in, the communication permission time "T" and the zone number "6a" are described in the control information field of the communication permission packet and transmitted. The wireless terminals 7a, 7b, 7c in the zone 6a that have received the communication permission packet are identified as control packets by the packet disassembly unit 31 in FIG. 2, and can be transmitted by the control unit 21. When the communication permission time T described in the user information field of this transmission permission packet has elapsed, the transmission is prohibited by the control unit of the wireless terminal. The wireless terminal 7e connected to the bridge of the zone 6b passes the communication permission time T of the zone 6a + guard time τ (maximum packet length + propagation delay time), and then, to the wireless terminals 7f and 7g of the zone 6b,
Send a communication permission packet. By this communication permission packet, the wireless terminal in zone 6b becomes ready for transmission. After that, this operation is sequentially repeated by the number of zones to be multiplexed with the same frequency, so that the transmission permission time is assigned to each zone.

By the way, in FIG. 1, when the wireless terminal 7a in the zone 6a and the wireless terminal 7f in the zone 6b communicate with each other, the zone 6a transmits a user information packet to the wireless terminal 7d connected to the bridge at the communication permission time. When the wireless terminal 7d connected to the bridge, which carries SA and DA, receives the signal, the bridge 4a transmits it to the bridge 4b via the wired LAN 5. The wireless terminal 7e connected to the bridge of the zone 6b holds this packet until the transmission permitted time of the zone 6b is reached, and when it reaches the transmission permitted time, the wireless terminal 7e transmits the user information packet and transmits it.
By receiving this packet, the wireless terminal 7a communicates with the wireless terminal 7f. Communication from the wireless terminal 7f to the wireless terminal 7a is performed in the reverse order of the procedure just described.

In the above example, the communication permission time T of each zone is explained as a fixed time, but it can be variably assigned according to the traffic of each zone. For example, the number of collisions detected by the collision detection unit 20 of the wireless terminal connected to the bridge of each zone is counted, the communication permission time is long for the zone 6b with a large number of collisions, and the communication permission is provided for the zone 6a with a small number of collisions. Allocate shorter time (Fig. 6 (1))
As a result, the throughput of the entire system can be improved.

Further, as shown in FIG. 6 (2), it is conceivable that there will be wireless terminals waiting for transmission between the transmission permission time of the zone 6a and the transmission permission time of the next zone 6a.
Since these wireless terminals try to transmit immediately after receiving the next transmission permission packet, collision easily occurs at the beginning of the permission time. In order to solve this problem, the transmission probability may be determined in advance for each wireless terminal, and after detecting the transmission path empty, the transmission may be started with this probability. For example, if the transmission probability of each wireless terminal is 0.2 and there are five waiting wireless terminals a to e, the probability of collision occurring at the beginning of the next transmission permission time should be reduced to 0.26. You can By thus setting the transmission probability of the wireless terminal to be smaller than 1, it is possible to prevent a decrease in throughput due to a collision.

Further, by using a plurality of frequency bands, FIG.
It is also possible to simultaneously perform frequency multiplexing and time division multiplexing as in (3). This figure shows zones 6a, 6b, 6c,
There are 4 zones of 6d, and there are two frequency bands f1 and f2.
It shows an example of performing communication using. Next, FIG.
An example of a procedure in which the terminal of each zone recognizes its own zone number will be described using the flowchart of FIG.

When the wireless terminal cannot correctly recognize the transmission permission packet of its own zone (in the communication disabled state), the wireless terminal connected to the bridge is turned on when the power of the wireless terminal is turned on, when zones are added or removed. When there is a failure, or when operating in one zone. At this time, each wireless terminal recognizes the zone by the following procedure. First, the control unit 21 sets the timer 1 of T1 which is longer than the time NT in which transmission permission is assigned to all zones (the number of zones N).

Next, all transmission permission packets that the wireless terminal can receive are received, and the zone number and reception level PrN in each packet are recorded. Receive transmission permission packets sequentially,
The zone number of the transmission permission packet having the highest reception level when the transmission permission packet having the same zone number is received is recognized as the own zone.

If timer 1 times out, it is assumed that zone recognition has failed, timer 2 of T2 that is sufficiently longer than T1 is set, and this wireless terminal does not perform time division, and the access protocol of normal CSMA / CD is used. Send at. This terminal performs zone recognition again due to T2 timeout. Thereby, each wireless terminal can recognize the zone to which it belongs.

The collision detection field is the same as the random pulse transmission field. In particular,
As shown in FIG. 11, the random pulse transmission field is divided into 18 slots, one of which is the first slot (0th slot) and 17 slots of 1st to 17th are randomly selected. The carrier signal is transmitted to a total of 9 slots out of the 8 slots, and it is in a receiving state during the period of other slots to determine whether or not there is a signal transmitted by another wireless terminal.

In the example of FIG. 11, since the random pulse patterns sent by the wireless terminal 7a and the wireless terminal 7b are the same until the eighth slot, collision cannot be detected with each other. In the ninth slot, the wireless terminal 7a sends a carrier signal, whereas the wireless terminal 7b does not send a carrier signal. Therefore, by detecting the carrier signal sent by the wireless terminal 7a, the wireless terminal 7b detects a collision. be able to. on the other hand,
The wireless terminal 7a can detect the collision for the first time in the 13th slot in which the wireless terminal 7a does not send the carrier signal and the wireless terminal 7b sends the carrier signal. The wireless terminal 7b detects the collision again in the sixteenth slot and the wireless terminal 1a in the seventeenth slot.

Theoretically, collisions can be detected with each other if the patterns of random pulses transmitted by the two wireless terminals are partially different. Therefore, the collision miss rate is 1 when the random pulse patterns transmitted by the two wireless terminals are the same, and when the carrier signal is transmitted in 9 slots out of 18 slots as shown in FIG. 11, the collision miss rate is 1 / 17C
8

During the random pulse transmission, if the carrier signal is continuously transmitted from the next slot where the collision can be detected to the end of the random pulse transmission field, the time until the other party detects the collision is shortened, and the collision is detected. The detection can be made more reliable. For example, in the case of the random pulse pattern shown in FIG. 11, since the wireless terminal 7b can detect the collision in the ninth slot, the carrier signal is transmitted from the tenth slot to the seventeenth slot as shown by the thick line in FIG. Keep doing As a result, the wireless terminal 7a can detect the collision in the tenth slot and continuously transmits the carrier signal from the eleventh slot to the seventeenth slot.

As described above, according to the first embodiment, the wireless communication system allocates the time for permitting the transmission by the wireless terminals in this zone for each zone into which the wireless terminals are classified. Each wireless terminal can determine whether or not the received packet is sent by a wireless terminal within the same zone as itself. Therefore, even if there is a zone of wireless terminals that use the same frequency band in the vicinity because the frequency band is not sufficiently secured, and even when using a wired network or wireless network connected to the bridge of each zone, The path through which the packet is sent can be uniquely determined. Therefore, it is possible to avoid a situation in which a plurality of the same packets are sent to the destination wireless terminal and the traffic is unnecessarily increased.
Next, a second embodiment of the present invention will be described below with reference to the drawings.

FIG. 8 is a diagram showing a configuration example of a wireless LAN system of the equal distribution system to which the present invention is applied, and the same components as those in FIG. 1 are designated by the same reference numerals. In addition, 1a,
1b, 1c, 1d, 1e and 1f are wireless terminals. Two
Reference numerals a, 2b, 2c and 2d denote various information terminal devices such as data terminals such as personal computers and workstations, voice terminals, image terminals and the like, and 1a, 1b, 1c and 1 by digital interfaces 3a, 3b, 3c and 3d.
d and connected to each other by wireless communication.
FIG. 9 is a diagram showing an example of frequency allocation. Frequency f1-1
, F1-2, f1-3, f1-4 are used. here,
The use of multiple frequencies in one zone is to minimize the deterioration of transmission quality due to frequency selective fading, which is unavoidable in wireless communication.
-211887 "Wireless Information Communication Terminal" and Japanese Patent Application No. 03
This is because the data to be transmitted is divided into four streams and the four carrier signals having different frequencies are modulated and transmitted, as proposed in -2188686 "Wireless Information Communication System".

FIG. 10 is a diagram showing an example of the frame structure.
For example, as an interface with various information terminal devices, I
When the AUI of EEE802.3 is adopted, the frame (AUI frame) configuration on the same interface is as shown in FIG. 10 (3).

On the other hand, there are two types of frame configurations for transmission in the wireless section, for example, two types shown in (1) and (2) of FIG. 10, where (1) shows the frame configuration of the control packet and (2) shows the AUI.
3 shows a frame structure of a user information packet for transferring user information transferred between various information terminal devices. The two types of packets are distinguished by the packet identifier, the control packet (FIG. 10 (1)) includes the control information field, and the user information packet (FIG. 10 (2)).
Includes a user information length and a user information field. Also,
The random pulse transmission field, preamble, frame start delimiter, zone identifier, target station address, transmission station address, address error detection additional bit, error detection additional bit, and error correction additional bit are common to the two types of packets. In the user information packet, the target station address, the transmission station address, the user information length, the user information field, and the error detection additional bit are the same as the frame structure on the AUI (FIG. 10 (3)). Each component of the frame will be described below. The random pulse transmission field is the same as the collision detection field described above in the first embodiment.

The preamble is a signal for the demodulation section of the wireless terminal on the receiving side to establish carrier synchronization and bit synchronization. The frame start delimiter is used by the receiving wireless terminal for frame synchronization. The zone identifier indicates to which zone the wireless terminal transmitting the wireless frame belongs, and is determined by the user for each zone.

The transmission station address and the destination station address are addresses of various information terminal devices connected to the wireless terminals on the transmission side and the reception side, and are the same addresses as those in FIG. 10 (3) transferred by the AUI.

The additional bit for address error detection is for detecting an error in the received zone identifier, transmission station address and destination station address. In order to increase the success rate of transfer of the zone identifier and the address, the same data sequence from the zone identifier to the additional bits for error detection is sent using each of the four frequencies shown in FIG. in this case,
If the zone identifiers and addresses in one or more data sequences can be transferred without error, it is possible to request the sending terminal to resend when an error occurs in the data after the user information length.

FIG. 13 is a diagram showing a configuration example of a wireless terminal. Transmission data (user information) input to the wireless terminal from various information terminal devices via the digital interface
First, the I / F unit 50 performs level conversion, frame synchronization, speed conversion, and the like. Then, the packet configuration unit 51 adds a packet identifier and a zone identifier. The packet configuration unit 51 reads the zone identifier from the zone identification unit to add the zone identifier. The zone identification unit 61 stores a zone identifier for identifying the zone to which the wireless terminal itself belongs, and the zone identification units 61 of all wireless terminals belonging to the zone store the same zone identifier. The scrambler 52 scrambles the data to randomize it. Thereafter, the coding unit 53 performs coding for error correction and error detection, divides into four sequences, and adds the random pulse pattern generated by the collision detection unit 62 to the user shown in FIG. As an information frame structure, the signals are input to the modulators 81 to 84 and modulated, for example, four-phase PSK modulation is performed, and then the RF units 63 use different RF frequencies.
For example, in the case of zone 6a in FIG. 8, f1− in FIG.
1, f1-2, f1-3, and f1-4, respectively, and output from the antenna A. The frequency is instructed by the control unit 60 to the RF unit 63.

For the antenna, two antennas A and B are connected to the RF section 63 for antenna diversity, the antenna A is for both transmission and reception, and the antenna B is for reception only. The signal received by the antenna A is sent to the demodulation units 91 to 94 via the RF unit 63, and the signal received by the antenna B is sent to the demodulation units 95 to 98 via the RF unit 63.

For the control packet, the control unit 60 writes a packet identifier, a transmission station address, a destination station address, and control information to the packet configuration unit 51, and the packet configuration unit 51
Outputs these data and zone identifiers arranged in the order shown in FIG. After the scrambling unit 52 scrambles these data, the coding unit 53 performs coding for error correction and error detection, divides into four sequences, and adds a random pulse pattern generated by the collision detection unit 62. As the control frame structure shown in FIG. 10A, after being input to the modulator and modulated, the RF unit 63 converts each to a different RF frequency and outputs from the antenna A.

Regarding the code part 63, Japanese Patent Application No. 03-29
2588 “Communication system and error correction system in communication system”, if an error correction system is applied, one of the sequences transmitted by being divided into four cannot communicate due to the influence of frequency selective fading or the like. Even in the case of, if all the errors are corrected by the error correction code applied to each of the other three sequences, the correct communication can be performed.

Of the signals input from the antennas A and B, the signal of the designated RF frequency, for example, in the case of the zone 6a in FIG. 8, f1-1, f1-2, f1- in FIG.
The signals of frequencies f3 and f1-4 are subjected to level compensation, frequency conversion, band limitation, etc. in the RF unit 63, and then the signal from the antenna A is demodulated to the demodulation units 91 to 94 and the signal from the antenna B is demodulated. It is input to the unit 95 to the demodulation unit 98. The demodulation unit performs carrier synchronization, demodulation (for example, 4-phase PSK demodulation), clock synchronization (clock reproduction), and carrier detection, and decodes the carrier detection signal, demodulation clock, and demodulation data into the decoding unit 73.
Send to. Further, the carrier detection signal is sent to the collision detection unit 62. Here, the carrier detection signal is a signal that is 1 when the level of the signal input from the RF unit 63 to the demodulation unit is within a specified frequency band, and 0 when the level is less than the specified value. When a packet is normally received, only 1 slot with carrier transmission is received during reception of the random pulse transmission field, and 1 is continuously set from the preamble to the additional bit for error correction.

The data output from the demodulator is used by the decoder 7
Error correction / error detection / descramble unit 72
After descrambling in, the packet disassembly unit 71 first checks the zone identifier. Packet decomposer 7
1 reads the zone identifier from the zone identification unit 61,
When the zone identifier in the packet is different from the one read from the zone identification unit 61, the packet is determined to be invalid and the packet is discarded. If the zone identifier in the packet is the same as that read from the zone identification unit 61, the packet is determined to be valid, and the packet identifier is checked next. Then, in the case of the user information packet, the frame on the AUI (FIG. 10 (3))
And is sent to various information terminal devices via the I / F unit 70. In the case of a control packet, the control unit 60 reads the content.

FIG. 14 is a diagram showing a transmission procedure of the wireless terminal. For example, the wireless terminal 1a is connected to the information terminal device 2a by A
When the UI frame is received, if it is determined as a result of carrier sensing that the transmission path is empty, a random pulse is transmitted in the random pulse transmission field of FIG. 10 (2). When a pulse transmitted by another wireless terminal is received in the random pulse transmission field, the wireless terminal determines that a collision has occurred, backs off, and repeats the operations after carrier sensing. If the number of collisions reaches a certain number,
The transmission procedure ends. When it is determined that no collision has occurred, a radio frame after the preamble is generated and transmitted. When a retransmission request from the target station is received within a predetermined time, backoff is performed and the operations after carrier sense are repeated. When the number of retransmissions reaches a predetermined number, the transmission procedure is ended. When the retransmission request from the target station is not received within the predetermined time, the transmission procedure ends.

FIG. 15 is a diagram showing a receiving procedure of the wireless terminal. Upon receiving the wireless frame, the wireless terminal first checks the zone identifier in the wireless frame. When it is determined that the packet is not valid, the packet is discarded. If the packet is determined to be valid, then the packet identifier is checked. If the packet is a control packet, the operation according to the contents of the packet is performed, and the reception procedure ends. In the case of the user information packet, a frame on the AUI (Fig. 10 (3)) is configured and
It is sent to the information terminal device via the UI. Further, when the address can be correctly received and the target station address belongs to the own terminal, and if an uncorrectable error is detected after the user data length, the wireless terminal requests the transmitting terminal to resend.

As a resending procedure, when the wireless terminal on the receiving side correctly receives at least the address and detects an uncorrectable error after the user data length, a resending request is sent to the sending terminal, while the user There is also a method of sending a reception completion notification to the transmitting terminal when the data length and beyond are correctly received. Further, there is a method in which the wireless terminal on the transmitting side retransmits the packet up to a prescribed number of times when the transmitting side receives the resend request or does not correctly receive the reception completion notice within the prescribed time.

Further, in the case of a system in which the frequency band for transmitting packets is changed with time,
A procedure of performing resending after the frequency band is changed, or a procedure of changing the frequency band when retransmission is necessary are also conceivable.

Next, an example of implementing the wireless communication system using the zone identifier in the wireless LAN system shown in FIG. 8 will be described. Here, 1a, 1b, and 1e belong to the zone 6a, and the zone identifier "6a" is recorded in each zone identification part. Further, 1c, 1d, and 1f belong to the zone 6b, and the zone identifier "6b" is included in each zone identification part.
Is recorded.

First, as an example of intra-zone communication, 2a to 2
The case of performing communication to b will be described. First, 2a is 3
The packet a shown in FIG. 16 is sent to 1a via a. Next, 1a transmits the packet b shown in FIG. 16 to the wireless space by the operation described with reference to FIG. Here, the zone identifier of packet b is "6a". 1b, 1
When e receives the packet b, it judges that the packet b is valid by the operation (zone identifier collation) described with reference to FIG. 15, and the packet c shown in FIG. , 4a. Packet a
And the packet c are the same. At this time, packet b
Even if 1c, 1d, or 1f receives the packet b, the operation shown in FIG.
1c and 1e determines that packet c is 2
It is not sent to c and 4b. The bridge function 4a determines that the DA of the packet b belongs to the information terminal device in its own zone and does not send the packet to the wired LAN 5. In this way, it is possible to prevent intra-zone communication from intermingling with communication in other zones.

That is, assuming that 4a is an information terminal device similar to 2a, 2b, 2c, and 2d, and 6a and 6b are independent wireless LANs, packets from other wireless LANs are transmitted to the information terminal device and Can be removed before sending to the bridge.

On the other hand, as an example of communication across different zones, the case of communication from 2a to 2c will be described. First, 2a sends the packet a shown in FIG. 17 to 1a via 3a. Next, 1a transmits the packet b shown in FIG. 17 to the wireless space by the operation described with reference to FIG. Here, the zone identifier of packet b is "6a"
Is. When 1b and 1e receive the packet b, FIG.
By the operation described above, it is determined that the packet b is valid, and the packet c shown in FIG.
It is sent to 2b and 4a via 3e. The packet a and the packet c are the same. Even if the packets 1c, 1d, and 1f receive the packet b, the operation shown in FIG. 15 determines that the packet b is not valid, and 1c, 1d, and 1f are 2c,
No packets are sent to 2d and 4b. Further, in 2b, the DA of the packet c is different from its own, and therefore the user information is not sent to the upper layer.

On the other hand, when 4a receives the packet c from 1d, the bridge function determines that the DA in the packet c does not belong to the information terminal device in its own zone, and sends the packet c to the wired LAN 5. 4c is a wired L
When the packet c is received from the AN 5, the bridge function determines that the DA in the packet c belongs to the information terminal device in its own zone, and the packet c is set to 1 via 3f.
send to f. Next, 1f sends the packet d shown in FIG. 17 to the wireless space by the operation described with reference to FIG. Here, the zone identifier is "6b".

When the packets 1c and 1d receive the packet d, the packet d is determined to be valid by the operation described with reference to FIG. 15, and the packet e shown in FIG.
To 2c, 2d via. The packet e is the same as the packet c, that is, the same as the packet a. At this time, even if the packets 1a, 1b, and 1d receive the packet d, the operation shown in FIG. 15 determines that the packet b is not valid, and does not send the packets to 2a, 2b, and 4a. Also,
2d does not send the user information to the upper layer because the DA of the packet e is different from its own. Thus, in the inter-zone communication, the communication route can be made unique.

As described above, according to the second embodiment, the zone identifier is added to the packet communicated between the wireless terminals,
Each wireless terminal monitors the zone identifier added in the received packet and sends the communication data to the information terminal and the bridge according to the data of this zone identifier. It is possible to prevent communication data from being mixed in from the stage before being sent to the information terminal or bridge. That is, communication within the zone is terminated within the zone,
Communication between zones can be made unique, and unnecessary increase in traffic volume can be prevented.

Further, whether or not the transmitted packet has arrived at the destination wireless terminal can be confirmed by a retransmission request packet or the like, and if it has not arrived, it can be retransmitted at the same frequency or a different frequency, so the packet discard rate can be lowered. It will be possible.

Further, as an example of classifying a plurality of wireless terminals into a plurality of zones, when the groups are grouped according to the organization, network configuration, security, companies, etc., the areas overlap in location. However, according to the present invention, there is no fear that the wireless communication system will be hindered.

In the first and second embodiments, the method of dividing the communicable time for each zone and the zone in the packet even if the wireless terminal has only one frequency band A wireless communication system can be realized by a method of distinguishing communication for each zone by an identifier, and even if there is another wireless communication system using the same frequency band, an inappropriate packet may be received due to simultaneous broadcast. Since it does not exist, there is no erroneous operation in the upper layer program. The present invention is not limited to the above embodiment.

In the above-described embodiment, the plurality of zones are connected by the wired LAN, but wireless connection is also conceivable. This wireless connection can also be realized by a specific wireless terminal having a function as a gateway station (master station) without going through a bridge. Furthermore, although it has been mentioned that a bridge is used to construct a LAN having a plurality of zones, this bridge is only an example, and any bridge can be used as long as it has a function of a gateway station (master station). It doesn't matter.

As a communication form, both the access control system and the information transmission system are premised on the equal distribution system which is a distributed system. However, both of them are a centralized system, the access control is a centralized system, and the information transmission system is a distributed system. The present invention can also be applied to the method described in 1.

Although the random pulse method was applied as the collision detection method, other collision detection methods such as the bit collation method are applied, the CSMA method which does not detect the collision, and the AL method.
It is also possible to apply the OHA method or the like. Although 4-phase PSK was applied as the modulation method, 2-phase PSK, MSK, 1
It is also possible to apply other modulation schemes such as 6QAM.

Although a multi-carrier transmission system is premised as a measure against fading and delay dispersion, what kind of method is used as a transmission method in a wireless section such as other spread spectrum system (SS) such as direct spread system. It doesn't matter. It is also applicable to optical transmission systems.

[0070]

According to the present invention, the control means carries out the receiving process when the arbitrary information received by the communication means is judged as the information to be communicated within its own group. , The wireless communication means does not confuse arbitrary information communicated by the wireless communication means of the other group with arbitrary information communicated by the wireless terminal means of its own group, so that the traffic is unnecessarily increased. It is possible to avoid such a situation.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a wireless LAN system of an equal distribution system in a first exemplary embodiment of the present invention.

FIG. 2 is a block diagram of a wireless terminal according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a packet frame structure in the first exemplary embodiment of the present invention.

FIG. 4 is a diagram showing a packet frame configuration in the first exemplary embodiment of the present invention.

FIG. 5 is a diagram showing an example of allocation of communication permission time of zones in the first embodiment of the present invention.

FIG. 6 is a diagram showing an example of allocation of communication permission time of zones in the first embodiment of the present invention.

FIG. 7 is a flowchart showing a zone recognition procedure of a wireless terminal in the first embodiment of the present invention.

FIG. 8 is a diagram showing a configuration example of a wireless LAN system of an equal distribution system according to a second embodiment of the present invention.

FIG. 9 is a diagram showing an example of frequency allocation in the second embodiment of the present invention.

FIG. 10 is a diagram showing a packet frame configuration in the second exemplary embodiment of the present invention.

FIG. 11 is a diagram showing a random pulse pattern in the second embodiment of the present invention.

FIG. 12 is a diagram showing a random pulse pattern in the second embodiment of the present invention.

FIG. 13 is a block diagram of a wireless terminal according to a second embodiment of the present invention.

FIG. 14 is a flowchart showing a transmission procedure of the wireless terminal in the second embodiment of the present invention.

FIG. 15 is a flowchart showing a receiving procedure of the wireless terminal according to the second embodiment of the present invention.

FIG. 16 is a diagram showing a packet frame structure during transfer in the second embodiment of the present invention.

FIG. 17 is a diagram showing a packet frame structure during transfer in the second embodiment of the present invention.

[Explanation of symbols]

1a-f ... Wireless terminal, 2a-d ... Information terminal device, 3a-
f ... digital interface, 4a-b ... bridge,
5 ... Wired LAN, 6a-d ... Zone, 7a-f ... Wireless terminal, 10 ... I / F section, 11 ... Packet configuration section, 12 ... Scramble section, 13 ... Encoding section, 14 ... Modulation section, 20 ... Collision detection Section, 21 ... control section, 30 ... I / F section, 31 ... packet decomposing section, 32 ... descramble section, 33 ... decoding section,
34 ... Demodulation section, 40 ... RF section, 41 ... Antenna, 50 ...
I / F section, 51 ... Packet configuration section, 52 ... Scramble section, 53 ... Encoding section, 60 ... Control section, 61 ... Zone identification section, 62 ... Collision detection section, 63 ... RF section, 70 ... I / F
Part, 71 ... packet disassembling part, 72 ... descramble part,
73 ... Decoding section, 81-84 ... Modulation section, 91-98 ... Demodulation section, A, B ... Antenna

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Koichiro Kamura, Inventor, 70, Yanagimachi, Sachi-ku, Kawasaki, Kanagawa Prefecture, Toshiba Yanagimachi Co., Ltd. (72) Takashi Kinouchi, 70, Yanagimachi, Sachi-ku, Kawasaki, Kanagawa Prefecture Within

Claims (8)

[Claims] 1. A wireless communication system in which a plurality of information communication terminals are classified into a plurality of groups, and wireless communication means is used for communication between at least information communication terminals classified into the same group, wherein the wireless communication means is , At least communication means for wirelessly transmitting and receiving the arbitrary information between the information communication terminals that are classified into the same group, and information that the arbitrary information received by this communication means is to be communicated within its own group And a control unit that performs a predetermined communication process based on the determination result by the determination unit, wherein the control unit determines that any information received by the communication unit is A radio communication system, characterized in that reception processing is performed when a judgment result with information to be communicated within a group is obtained from the judgment means. 2. The wireless communication means has a communicable range at least partially overlapping with another wireless communication means of at least one group different from the group to which the wireless communication means belongs,
The frequency bands used by the wireless communication means and the other wireless communication means are the same.
The wireless communication system according to. 3. The wireless communication system according to claim 1, wherein the control means starts the transmission operation by the communication means based on a predetermined probability. 4. The determination means changes the determination result at a predetermined cycle, and the control means performs a predetermined transmission process based on the determination result by the determination means even in the transmission by the communication means. The wireless communication system according to claim 1, wherein the wireless communication system is a wireless communication system. 5. The wireless communication system according to claim 4, wherein the predetermined cycle is a variable time. 6. The determining means determines whether or not the arbitrary information is information to be communicated within its own group, based on the group identification information added to the arbitrary information, and the control means is The wireless communication system according to claim 1, wherein at least the group identification information is added to arbitrary information at the time of transmission. 7. The control means, when an error is detected in arbitrary information at the time of reception, requests the source communication means of the arbitrary information to retransmit the information, and when the retransmit is requested, the control means sets a predetermined value. The wireless communication system according to claim 1, wherein the arbitrary information is retransmitted by the procedure of. 8. The wireless communication system according to claim 6, wherein the predetermined procedure assigns a frequency band different from the previous one when the communication means retransmits arbitrary information.