JPH08186567A - Radio lan system - Google Patents

Abstract

PURPOSE: To provide a flexible network by processing a communication request for a certain station under communication sequentially without rejecting the request and making simultaneous access from plural terminal stations to the certain terminal station possible. CONSTITUTION: A control station 10 is provided with transmission/reception parts TRX1 -TRXn, TX1 -TXn and TRXC of all channels, and divides a frequency band used for communication for access control into plural channels. Stations (terminals) 201 -20n other than the control station are provided with one of dedicated channels TRX1 -TRXn for transmission/reception data transfer and a channel TRXC for control common to each station, and output the communication request to the control station by using the channel for control when performing the communication. The control station 10 performs the setting of a switching function 11 so as to connect a signal received from the channel of a communication request origin to that of a communication request destination, and after that, returns a response to the request origin by using a control channel. When the communication request destination is busy, the control station holds the communication request transiently by connecting to a queue, and connects it when the terminal station of the communication request destination becomes free.

Description

Detailed Description of the Invention

[0001]

This invention relates to a wireless LAN (Local).
Area Network) system.

[0002]

2. Description of the Related Art A method of implementing a wireless computer network is roughly classified into two types: a centralized management system in which a control station exists and a distributed management system in which no control station exists. The former is a method in which a control station performs access control to avoid collision, and the latter is a method in which each station in the network performs collision detection / control. Further, as a hybrid system, a method of managing a centralized system for a control system and a distributed system for a data system is also known. Also, regarding the channels used at that time, it is known that a control channel and a plurality of channels are prepared for data transfer.

[0003]

As described above, as a network system using radio, a system using a plurality of data channels has been proposed. However, this system cannot communicate with a terminal that is already communicating. In such a case, the other party is busy and the connection fails, and it is common to try to reconnect with a higher level protocol (or application) on the terminal side. However, as the wireless network frequency becomes higher, the band becomes wider, and the data transfer rate is dramatically increased. In such a system, it is faster to process a plurality of connection requests simultaneously issued to a certain station in the control station as much as possible. In addition, it is necessary to preferentially process data communication such as voice data, which has a time constraint, and to return a connection failure to the terminal if the connection cannot be made within the required time.

In a wired network, a device called a switching hub is provided in order to improve the poor throughput of a contention-based bus type (shared type) network system. This is a device that has a port for connecting to each terminal and a high-speed switching function, and can connect between ports according to a connection request from the terminal. Even if the number of terminals increases in the wired network, it can be handled by adding switching circuits and ports. However, in the case of wireless, the usable band is limited, and simply allocating one channel to each terminal will exhaust the band immediately. For example, if a 100 MHz band is divided into 1 channel and 10 MHz, the maximum is 10
Only channels can be taken, and there are only 10 terminals, and it is impossible to connect.

The present invention is intended to solve the above problems, and an object thereof is to allow a plurality of connection requests to the same station, to enable time-constrained data communication, and to use radio waves that are a limited resource. It is to provide a highly flexible network system in which the number of terminals accommodated is large and the communication speed can be dynamically changed by effectively utilizing.

[0006]

In order to solve the above problems, the present invention provides (1) a wireless computer network comprising a control station and stations (terminals) other than the control station, wherein the control station Has a transceiver for all channels,
The stations (terminals) other than the control station each have one dedicated transmission / reception data transfer channel and a common control channel for each station, and the control station divides the frequency band used for communication for access control into a plurality of channels. When performing communication, the request source station (terminal) issues a communication request to the control station using the control channel, and the control station connects the signal received from the communication request source channel to the communication request destination channel. In a network that returns the response to the requester using the control channel after setting the exchange function and notifies the control station of the completion of communication using the control channel when communication is completed,
When the communication request destination is already communicating, the control station temporarily holds the communication request by connecting it to a queue, and the connection is made when the communication request destination station becomes available. Yes, and (2) in (1), the communication request is given priority, and the communication request having a higher priority is connected to the front of the queue, and (3) above (1). Alternatively, in (2), the control station has a timer and a function capable of interrupt processing by an interrupt activated by the timer, and the communication request source specifies a time until communication establishment, and even if the specified time is exceeded. When the connection cannot be established, the control station returns a negative response to the communication request source, and further (4) in any one of (1) to (3) above,
Having a frequency band of the control channel in a frequency band different from that of the data transfer channel, or (5) a computer network using a radio composed of a control station and stations (terminals) other than the control station, A station has a transmission / reception unit for all channels, and a terminal has a transmission / reception channel for all channels and a control channel common to all stations.When communicating, the requesting terminal uses the control channel to control the station. A wireless LAN characterized in that a communication request is issued and the control station establishes communication between both terminals when the communication destination terminal is free and there is an empty channel, and releases the used channel after the communication is completed. In the system, the terminal is
When the communication data amount is large, the control station requests the field value of the required band to be large, and the control station allocates a plurality of channels to the terminal station to increase the band, and further, (6) above (5) ), The communication request is given priority, and the communication request having a higher priority is connected to the front of the queue. Further, (7) the control station and a plurality of stations (terminals) other than the control station. In the computer network using wireless, the control station divides a frequency band used for communication for performing access control into a plurality of channel groups, the plurality of terminals are divided into some groups, and each terminal is Each terminal belongs to any one of the channel groups, and each terminal has as many transmission / reception channels as the channels of the group to which the terminal belongs, and further, in (7), which group is (8) Has a reserved channel that does not belong to any other group, or (9) uses the reserved channel when performing highly urgent data communication, or (10) when a certain terminal has a large amount of communication data, the control station Increases the band by allocating a plurality of channels to the terminal, or (11) when the communication data amount of a terminal station is large, the control station allocates the reserved channel to the terminal station to increase the band. It is characterized by.

[0007]

The present invention provides a flexible network system in which communication requests to stations already in communication are processed in order without being rejected, thereby enabling simultaneous access from a plurality of terminals to a certain terminal.

[0008]

【Example】

Embodiment 1 (corresponding to claim 1) FIG. 1 is a diagram showing a configuration of a network system of the present invention, in which 10 is a control station, 11 is a switching function block, and 1 is a switching function block.
2 is a control unit, 20 _{1 to} 20 n are terminals (stations other than the control station), RX _{1 to} RX _n are data channel reception units and demodulation units, and TX _{1 to} TX _n are data channel transmission units and modulation units, TRX ₁ ~ TRX _n is a data channel transceiver, and TRX _c is a control channel transceiver. Figure 2
Shows an example of a queue of communication request blocks, in which a band allocated for communication is divided into several channels and one is allocated to each wireless terminal for data communication. One channel is for control and can be accessed by all stations. The control station has access to all data and control channels. The control station has the ability to connect the data coming from all input channels to any output channel.

When a certain wireless terminal station A communicates with another station (terminal) B, it issues a communication request to the control station using the control channel. The communication request includes the address of its own station and the address of the communication request destination. The control station which receives this sets the exchange function in the control station so as to connect the channel allocated to the terminal A and the channel allocated to the terminal B. Further, the control station returns a response to the communication request source using the control channel. As a result, the request source knows that the connection has been established, and thus the communication is performed using the data channel. When the communication is completed, the control channel is used to notify the control station of the completion of communication. As a result, the control station sets the exchange function so as to release the connection between the channel assigned to the terminal A and the channel assigned to the terminal B.

If terminal B is communicating with another station,
The control station creates a communication request block and inserts it at the rear end of the communication queue (Fig. 2). The communication request block has a data structure in which addresses of the own station and the other party are written. When the communication completion is notified from the terminal B or the station communicating with the terminal B to the control station, the control station extracts the communication request block from the head of the communication queue and connects to the communication request source. Furthermore,
After that, a response signal is returned using the control channel to notify the request source that the connection has been established.

Second Embodiment (corresponding to claim 2) According to the first embodiment, a plurality of connection requests can be processed by the control station. In the second embodiment, a priority field is provided in the communication request block so that communication data having a higher priority can be processed. FIG. 3 shows a queue of the above-mentioned communication request block. In FIG.
≧ P2 ≧ Pn. When a station issues a communication request, the priority p is added to the addresses of the own station and the partner station. If the other party is communicating, the queue is checked from the beginning and inserted immediately before the first block having a priority lower than p.

Third Embodiment (corresponding to claim 3) In the third embodiment, the control station is provided with a timer whose minimum unit is a sufficiently short time, and an interrupt is taken every unit time. When the timer interrupts, the processing that has been performed up to that point is interrupted and the control program specified in advance is executed. When the execution of the interrupt processing is completed, the original processing is returned to. In this system, a connection request time field is further added to the communication request block. FIG.
Shows the queue of the above-mentioned communication request block, and when the communication request destination is already communicating and the communication request source requests the completion of connection within the time m, the connection request time field Create a communication request block in which m is written and connect to the queue. Each time an interrupt occurs, it looks at the request block in the communication queue to see if the connection request time has expired. If the current time has passed the requested time, the block is removed and a negative response is returned to the communication request source to inform that the connection has failed. There are several possible methods for checking the expiration of the time. For example, when creating a communication request block, write the current time + m and compare it with the current time each time an interrupt occurs, or m (the connection request time / Interval of timer interrupt), and each time an interrupt occurs, the connection request time field of all request blocks is decremented by 1 and the time when it becomes 0 is considered as the expiration.

Embodiment 4 (corresponding to claim 4) In general, the control channel has a smaller band than the data transfer channel because it carries less information. Therefore, it is conceivable to set the frequency band of the control channel to another band having a narrower band in order to make the band of the data transfer channel large. For example, a band having a wide band of 60 GHz is fully used for data transfer, and the control channel is set to the 2.4 GHz band or the like.

Embodiment 5 (corresponding to claims 5 and 6) According to Embodiment 1, it was possible to provide a wireless network system with high throughput. However, with this method, the transmission / reception channels assigned to each terminal are fixed, so the total number of units divided by the bandwidth per channel,
In other words, it is not possible to connect to all terminals (all bands / one channel band). However, not all terminals actually communicate at the same time. Therefore, all terminals are provided with transmission / reception units for all channels. FIG. 5 is a diagram for explaining the fifth embodiment, in which 10 is a control station and 20 is a control station.
_{1 to} 20n are terminal stations. When performing communication, the terminal stations
First, a communication request is issued to the control station 10 using the control channel. When the communication destination terminal station is vacant and there is a vacant channel, the control station which has received this informs both terminal stations of the vacant channel and establishes a connection for communication. When the communication is completed, the control station is notified of the communication completion. As a result, the control station collects the used channel and prepares for the next request. Also in this case, similarly to the first embodiment, a flexible network can be constructed by giving priority to communication requests and connecting communication requests having higher priority to the front of the queue.

Embodiment 6 (corresponding to claim 7) According to the embodiment 5, it is possible to provide a network system which effectively uses a limited frequency band and communicates between a large number of terminals. However, according to the method of the fifth embodiment, all the terminals have the transmission / reception units for all channels, so that the circuit configuration / control becomes complicated and the cost becomes high.
Therefore, the following configuration is used. First, all channels included in the entire frequency band are divided into a plurality of groups.
Here, the total number of channels is N, the number of divided groups is g, and the number of channels included in each group is n. Where n
≧ 1 and N ≧ g ≧ 1. When a terminal requests the control station for a channel to be used, the control station selects and allocates a free channel group from the channel group to which the terminal belongs.
When communication is completed, the used channel is released.

FIG. 6 is a diagram for explaining the seventh embodiment, in which 10 is a control station, 30 ₁ to 30 ₄ are channel groups, and FIG. 6 shows that terminals 1 to 3 are channel groups 30 ₁
, And the channels used in the channel group 30 ₁ are CH1 and CH2. Since there are only two channels for three terminals in this group, only two terminals can communicate at the same time. In addition, the channel group 30 ₂
The channels used in the above are CH ₃ and CH ₄ , and the number of terminals that can simultaneously communicate in this channel group 30 ₂ is 2
It is a stand. On the other hand, since the channel group 30 ₃ is allocated to the two terminals 8 and 9 of two channels of CH ₅ and CH ₆ , both of them can always communicate with each other. Such a channel group is effective when the terminal in the channel group frequently communicates, for example, a server. Further, as shown in the channel group 30 _4, if put attracting small communication frequency terminals into one channel group, fewer number of channels allocated is.

Embodiment 7 (corresponding to claims 8 and 9) According to Embodiment 6, it is possible to construct a flexible network according to the network usage status of the terminal. But,
Network usage changes dynamically. In the example described above, the terminals 10 and 11 belonging to the channel group 30 ₄ may simultaneously perform highly urgent data communication. Since only one channel CH ₇ is assigned to this group 30 ₄ , either one of them is waiting. In order to avoid this, channels that do not belong to any group are reserved, and when more channels than the number assigned to the groups are needed, they are temporarily assigned.

Embodiment 8 (corresponding to claim 10) Although the amount of communication data does not increase in an application such as remote login to another station, the amount of data is large when image data is transferred and high-speed network communication is possible. It is desirable to be able to. Therefore, a field of the required band (transfer rate) is provided in the communication request, and this value is set large when transferring a large amount of data. The control station which receives this monitors the state of the vacant channels and, if vacant, allocates a plurality of channels for transfer.

Embodiment 9 (corresponding to claim 11) This embodiment has a function of dynamically purchasing a band using the reserved channel described in Embodiment 7 when the amount of communication data is large. When the communication data amount of a certain terminal station is large, the control station allocates the reserved channel described in the seventh embodiment to the terminal to increase the band.

[0020]

As is apparent from the above description, the present invention has the following effects. Effect corresponding to claim 1: Communication requests to stations already in communication are processed in order without being rejected. Therefore, a plurality of terminals can access a certain terminal at the same time, and a flexible network system can be provided. Effect corresponding to claim 2: Give priority to communication data,
It is possible to provide a network system in which higher priority data is processed first. Effect corresponding to claim 3: It is possible to provide a network system in which a condition of time required for connection is set and a negative response is returned when connection cannot be made within the set time. This allows higher-level protocols or applications to discard, for example, data that is temporally continuous, such as data that fails to meet time constraints when sending audio, video, etc. Can be protected.
Usually, a large transmission delay causes a deterioration in quality of these data rather than a partial loss thereof, so that high quality communication can be performed by this network. Effect corresponding to claim 4: Data requiring high-speed transfer can be efficiently sent using a wide frequency band. Effect corresponding to claim 5: It becomes possible to effectively use a limited frequency band and perform communication between a large number of terminals. Effect corresponding to claim 6: It is possible to provide a network system in which communication data is given priority and data of higher priority is processed first. Effect corresponding to claim 7: A network with simple circuit configuration and control and low cost can be constructed. Furthermore,
It is possible to build a flexible network system according to the network usage status of each terminal. Effects corresponding to claims 8 and 9: It is possible to provide a more flexible network system in which the number of usable channels changes according to the dynamically changing network usage status. Effects corresponding to claims 10 and 11: Not only the number of usable channels but also the bandwidth of one communication can be dynamically changed, and a flexible network system can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining a network system according to a first aspect of the invention.

FIG. 2 is a diagram for explaining a queue of the invention described in claim 1;

FIG. 3 is a diagram for explaining a queue of the invention described in claim 2;

FIG. 4 is a diagram for explaining a queue of the invention described in claim 3;

FIG. 5 is a diagram for explaining details of stations other than the control station of the invention according to claim 5;

FIG. 6 is a diagram for explaining a channel group of the invention described in claim 7;

[Explanation of symbols]

10 ... Control station, 20 _{1 to} 20 n ... Terminal, 30 ₁ to 30 ₄ ...
Channel group, RX _{1 to} RX _n ... Data channel receiving unit and demodulating unit, TX _{1 to} TX _n ... Data channel transmitting unit and modulating unit, TRX _{1 to} TRX _n ... Data channel transmitting / receiving unit, TRX _c ... Control channel Transmitter / receiver.

Claims (11)

[Claims] 1. A wireless computer network comprising a control station and stations (terminals) other than the control station, comprising:
The control station has a transmission / reception unit for all channels, and stations (terminals) other than the control station have one dedicated transmission / reception data transfer channel and a common control channel for each station, and the control station performs access control communication. The frequency band used for is divided into multiple channels, and when communicating, the requesting station (terminal) issues a communication request to the control station using the control channel, and the control station receives from the communication requesting channel. A network that sets the switching function to connect the signal to the communication request destination channel, returns a response to the request source using the control channel, and uses the control channel to notify the control station when the communication is completed. In (2), when the communication request destination is already communicating, the control station temporarily holds the communication request by connecting it to the queue, and connects when the communication request destination station becomes available. Wireless LAN and performs
system. 2. The wireless LAN system according to claim 1, wherein the communication request is given priority, and the communication request having a higher priority is connected to the front of the queue. 3. The control station has a timer and a function capable of interrupt processing by an interrupt activated by the timer, the communication request source specifies a time until communication establishment, and the connection is made even after the specified time has passed. The wireless LAN system according to claim 1, wherein the control station returns a negative response to the communication request source when the communication cannot be performed. 4. The wireless LAN system according to claim 1, wherein the control channel has a frequency band in a frequency band different from that of the data transfer channel. 5. A wireless computer network comprising a control station and stations (terminals) other than the control station,
The control station has transmission / reception units for all channels, and the terminal has transmission / reception channels for all channels and a control channel common to all stations. When performing communication, the requesting terminal uses the control channel to control the station. A wireless communication characterized by establishing a communication between both terminals when the communication destination terminal is idle and there is an empty channel, and releasing the used channel after the communication is completed. In the LAN system, when the communication data amount is large, the terminal requests the control station to make a large field value of the required bandwidth,
A wireless LAN system in which a control station increases the band by allocating a plurality of channels to the terminal station. 6. The wireless LAN system according to claim 5, wherein the communication request has a priority, and the communication request having a higher priority is connected to the front of the queue. 7. A wireless computer network comprising a control station and a plurality of stations (terminals) other than the control station, wherein the control station uses a plurality of channel groups for frequency bands used for communication for access control. And the plurality of terminals are divided into some groups and each terminal belongs to one of the channel groups, and each terminal has a transmission / reception channel for the channels of the group to which the terminal belongs. LAN system. 8. The wireless LA according to claim 7, which has a reserved channel that does not belong to any group.
N system. 9. The wireless LAN system according to claim 7, wherein the reserved channel is used when performing highly urgent data communication. 10. When the communication data volume of a certain terminal is large,
The wireless LA according to claim 7, wherein the control station increases the band by allocating a plurality of channels to the terminal.
N system. 11. The wireless LAN system according to claim 7, wherein when the communication data amount of a certain terminal station is large, the control station allocates the reserved channel to the terminal to increase the band.