JPH07312610A - Radio communication control system - Google Patents

Abstract

PURPOSE:To flexibly cope with environmental changes without losing any characteristics by allowing one node to check the strength of received radio waves from an opposite side node, informing the opposite side of it and controlling the transmission output of the opposite side node based on this information. CONSTITUTION:A receiving part 1 of each computer terminal 101 (102) is a module to perform reception control as a computer terminal to perform data communication with radio waves as media and is equipped with a received signal strength detecting part 1a. When there is a radio link establishing request from a radio link establishing request source node, at a radio link establishing request destination node, the detecting part 1a detects the received signal strength of those requested radio waves. Then, the received signal strength is informed for the request source node by a signal strength informing part 2a. Therefore, a radio transmission output control part 3 controls transmission radio wave outputs to the request destination according to a signal strength informing signal from the request destination node at the request source node. Thus, in the case of following data communication, the transmission radio wave output can be lowered without degrading transmission quality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication control system for controlling output of transmitted radio waves in data communication of a network such as a wireless LAN.

[0002]

2. Description of the Related Art In recent years, personal computers (PCs)
2. Description of the Related Art Portable computers such as notebook PCs have become widespread due to miniaturization. A wireless LAN (local area network) is used as a means for performing data communication while taking advantage of the portability of a portable PC.
Is becoming popular. In the data communication of such a wireless LAN, unlike the existing wired LAN, it is necessary to establish a link prior to the data communication. This link establishment is a procedure peculiar to LAN using wireless as a medium, and the medium characteristics such as reflection and attenuation are complicated.

On the other hand, in the wireless LAN system, the maximum value of the radio wave output is regulated by the Radio Law, and the computer terminal cannot output the radio wave with the power exceeding the maximum value. However, since the environment in which the wireless LAN is installed is complicated in practice, conventionally, in order to ensure a certain transmission quality, radio waves have been unconditionally transmitted at the maximum value of this regulation.

[0004]

However, increasing the transmission output of radio waves means increasing the power consumption of the computer terminal. On the other hand, it is a major feature of the wireless LAN that data communication is possible while making the most of the portability of a portable computer. Therefore, unconditionally increasing the transmission output of the electric wave in this way has a problem that the load on the battery provided in the computer is large and the continuous operable time of the computer terminal is shortened.

Further, when the radio wave is output in advance with a value smaller than the maximum transmission radio wave output, there is a risk that it cannot cope with environmental changes such as movement of the computer terminal. Further, when AC power is supplied to a computer terminal by an AC adapter or the like instead of battery operation, there is a problem that the portability of the portable computer, which is the original characteristic, is impaired.

From these points, it has been desired to realize a wireless communication control system capable of flexibly coping with environmental changes without impairing the portability of the portable computer.

[0007]

In order to solve the above-mentioned problems, a wireless communication control system according to the present invention provides a wireless link establishment request source node to a wireless link establishment request destination node on a side receiving a wireless link establishment request. When the wireless link establishment request is received from the node, the reception strength detection unit that detects the reception strength of the radio wave and the reception strength detected by this reception strength detection unit are sent to the wireless link establishment request source node. A reception strength notification unit is provided. Further, the wireless link establishment request source node is provided with a wireless transmission output control unit for controlling the transmission radio wave output of the own node based on the reception strength notification signal from the wireless link establishment request destination node.

[0008]

In the wireless communication control system of the present invention, the wireless link establishment request destination node, when the wireless link establishment request source node issues a wireless link establishment request, determines the reception strength of the radio wave of the wireless link establishment request. The detection unit detects. Then, the reception strength notifying unit notifies the reception strength to the wireless link establishment request source node. As a result, in the wireless link establishment request source node, the wireless transmission output control unit controls the transmission radio wave output to the wireless link establishment request destination according to the reception strength notification signal from the wireless link establishment request destination node.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram of a wireless communication control system of the present invention. Prior to describing this system, a wireless LAN system to which the wireless communication control system of the present invention is applied will be described.

FIG. 2 is a block diagram of a wireless LAN system. In a wireless LAN system, a range in which communication is possible in one frequency band is called a cell, and a normal business office can cover an area with a radius of about 20 m. In the figure, reference numeral 100 is a wireless LAN microcell, and four computer terminals 101 to 104 are provided in the microcell 100 as nodes in the network. These computer terminals 101 to
Reference numeral 104 denotes a computer terminal that can communicate with each other via a wireless LAN. In this system configuration example, the computer terminals 102 and 10 are different from the computer terminal 101.
The distances 3 and 104 are 2 m, 5 m, and 40 m, respectively.

When two computer terminals communicate with each other, a communication link is established prior to data communication. That is, the transmission source transmits a communication link establishment request (request) to the transmission partner, and when communication is possible, the permission signal (ACK) from the transmission partner is received. As a result, a link is established between the transmission source and the transmission partner, and then actual data transmission / reception becomes possible.

In the procedure for establishing a link, in the first embodiment of the present invention, the receiving computer terminal checks the received signal strength of the link establishment request from the sender and notifies the sender of the strength. As a result, the transmission source can know the reception intensity of the radio wave received by the transmission partner. In addition, the computer terminals that have transmitted the wireless link establishment request also communicate with each other by notifying the other party of the reception strength of the wireless link establishment confirmation response,
It becomes possible to recognize the reception strength of the radio wave transmitted by the other party. Therefore, when the reception radio wave sensitivity is good, by lowering the transmission radio wave output and performing data communication,
It can reduce power consumption and extend battery life.

The first embodiment will be described below with reference to FIG. << Embodiment 1 >> In FIG. 1, 101 and 102 are microcells 1 in the wireless LAN system shown in FIG.
00 shows a computer terminal installed in the computer 00. Each of the computer terminals 101 and 102 includes a receiving unit 1, a transmitting unit 2, a wireless transmission output control unit 3, and an antenna 4. The receiving unit 1 of each computer terminal 101 (102) is a module that performs reception control as a computer terminal that performs data communication using wireless radio waves as a medium.
The reception intensity detector 1a is provided. The reception strength detection unit 1a has a function of detecting the reception strength of the radio wave when either the wireless link establishment request or the wireless link establishment confirmation response is received from the partner computer terminal 102 (101). is doing.

The transmission unit 2 is a module that performs a transmission operation as a computer terminal that performs data communication using radio waves as a medium, and includes a reception intensity notification unit 2a.
The reception strength notifying section 2a uses the reception strength detected by the reception strength detecting section 1a as the computer terminal 102 (1) of the other party.
01). Further, the wireless transmission output control unit 3 sends a control signal for transmitting radio wave output to the transmission unit 2 based on the reception intensity detected by the reception intensity detection unit 1a.

Next, the operation of the first embodiment will be described. FIG. 3 is an explanatory diagram of an operation sequence in which the computer terminal 101 and the computer terminal 102 mutually notify the reception strength when the wireless link is established. First, the computer terminal 101 transmits a wireless link establishment request to the computer terminal 102, which is a communication partner, before transmitting data. The computer terminal 102 is the computer terminal 1
The receiving unit 1 receives the link establishment request from 01, analyzes the request, and the reception intensity detecting unit 1a checks the reception radio wave intensity. Then, the computer terminal 102
The reception strength notification unit 2a of the transmission unit 2 transmits the reception radio field strength data to the computer terminal 101 together with the wireless link establishment confirmation response.

In the computer terminal 101, the receiving unit 1 receives the data and recognizes that the wireless link has been established. Furthermore, the computer terminal 1 of the radio wave transmitted by itself
Since the reception intensity on the 02 side can be recognized, the wireless transmission output control unit 3 instructs the transmission unit 2 to reduce the transmission radio wave output to a possible level without decreasing the data transmission quality in the subsequent data communication. To do. At the same time, the reception strength detection unit 1a of the reception unit 1 checks the reception strength of the wireless link establishment confirmation response from the other party. Then, the reception strength notifying unit 2a notifies the computer terminal 102 of the reception strength.

Upon receiving the notification of the reception strength, the computer terminal 102 instructs the wireless transmission output control section 3 to instruct the transmission section 2 to reduce the transmission radio wave output as in the operation on the computer terminal 101 side. By the above operation, it becomes possible to reduce the power consumption of the power supply by lowering the transmission radio wave output without lowering the transmission quality in the subsequent data communication.

Further, a specific example of the wireless communication control system of the first embodiment will be described. FIG. 4 is a configuration diagram of the specific example. The figure shows the configuration of one computer terminal (here, the computer terminal 102).
The antenna 4, the wireless reception interface 5, the wireless transmission output control unit 9, the A / D converter 10, the transmission control unit 11, the wireless transmission interface 12, and the reception control unit 15.

The antenna 4 is for transmitting and receiving radio waves to and from the computer terminal 101, as in FIG. The wireless reception interface 5 is an interface on the reception side, and includes a filter 6, a buffer amplifier 7,
It comprises a demodulation circuit 8. The filter 6 filters the radio wave received by the antenna 4, and the buffer amplifier 7 has a function of receiving the output of the filter 6 and detecting the received intensity from the received radio wave. The transmission output control unit 9 is notified. The demodulation circuit 8 is a demodulation circuit that demodulates a received signal, and the demodulated received data is passed to an internal circuit (not shown) for data processing.

The radio transmission output control unit 9 controls the radio transmission output based on the reception intensity signal from the buffer amplifier 7 and sends the control signal to the radio transmission interface 12. The A / D converter 10 has a function of converting an analog signal of reception intensity into a digital signal and outputting the digital signal to the transmission control unit 11. The transmission controller 11 is the reception controller 1
5, the data to be transmitted is generated based on the analysis result of the received data (for example, whether or not it is a wireless link establishment request, etc.) and the received strength signal from the A / D converter 10, and this data is wirelessly transmitted. Output to the interface 12.

The wireless transmission interface 12 is an interface on the transmission side and is composed of a driver 13 and a modulation circuit 14. The modulation circuit 14 is a circuit that modulates the transmission data output from the transmission control unit 11 into radio data, and the driver 13 is a driver that sends the data modulated by the modulation circuit 14 to the antenna 4. The output is configured to be controlled based on the control signal of the wireless transmission output control unit 9. Also, the reception controller 1
As described above, the reference numeral 5 analyzes the received data from the output of the demodulation circuit 8 and outputs the analysis result and the like to the transmission control unit 1.
It is configured to deliver to 1.

Next, the operation when establishing a wireless link in the computer terminal 102 of such a specific example will be described.
First, a computer terminal 101 not shown in the figure
The wireless link establishment request from the antenna 4 is received by the antenna 4 and passed to the filter 6. The radio wave from the received radio wave is filtered by the filter 6.
The frequency used in the AN system is extracted and passed to the buffer amplifier 7. The buffer amplifier 7 checks the received signal strength and notifies the wireless transmission output control unit 9 of the checked received signal strength. The output of the buffer amplifier 7 is demodulated by the demodulation circuit 8 and passed to the reception control unit 15, where the data received here is analyzed.

When the reception controller 15 recognizes that the received data is a wireless link establishment request, it instructs the transmission controller 11 to make a wireless link confirmation response. Upon receiving the instruction, the transmission control unit 11 outputs the wireless link establishment confirmation response and the reception intensity passed from the A / D converter 10 to the modulation circuit 14. The data subjected to wireless data modulation by the modulation circuit 14 is passed to the driver 13 and transmitted from the antenna 4 according to the radio wave output level instructed by the wireless transmission output control unit 9.

On the other hand, the computer terminal 101 also has a configuration similar to that of the computer terminal 102 shown in the figure, and similarly to the operation of the computer terminal 102 described above, it receives and receives the wireless link establishment confirmation response and the reception strength of the partner station. The strength is checked and the reception strength is notified to the other computer terminal 102. In addition, the partner computer terminal 10
Recognize the reception intensity at 2.

From the above, the computer terminals 101, 1
02, it is possible to recognize the radio wave reception intensity at the partner computer terminal. Therefore, if the radio reception strength at the other end is good, it can be judged that a certain transmission quality can be secured even after the radio wave output is reduced. The load can be reduced.

In addition, even if the distance between the computer terminals is short or there is an obstacle such as a partition or a wall between them, in this embodiment, the data communication can be performed in the optimum state. FIG. 5 is an explanatory diagram of such a state. In the figure, reference numeral 200 is a microcell of the wireless LAN system, and 201 to 204 are the microcells 200.
There are four computer terminals located inside. Then, the computer terminal 201 and the computer terminal 202
The partition 300 is located between and.

In such a state, the partition 30
Although the medium characteristics such as reflection and attenuation are complicated depending on the shape of 0, the installation position, etc., in the present embodiment, when establishing a link, each of the computer terminals 201 and 20 described above is connected.
The computer terminal 2 is used to control the output of the radio wave transmitted by the computer 2.
It is possible to obtain a certain transmission quality at the time of link establishment while minimizing the battery load of 01 and 202.

In the first embodiment, the two computer terminals such as the computer terminals 101 and 102 control the output of the transmitted radio waves, but the control may be performed only on one side. For example, the computer terminal 101 described above is a battery-powered portable computer, but the computer terminal 102 on the data receiving side of the computer terminal 101 is fixedly installed and is
It may be driven by a power supply. This may be the case in a system in which one is a portable computer, the other is a cordless printer buffer when it is a printer, one is a handy terminal that emphasizes portability, and the other is a host device that receives it.

In such a case, assuming that the wireless link establishment request source node is a portable computer and the wireless link establishment request destination node is an AC power source driven computer terminal, the AC power source driven computer terminal is connected to the wireless terminal from the portable computer. When receiving a link establishment request, a reception strength detection unit that detects the reception strength of the radio wave,
A reception strength notification unit that notifies the reception strength detected by the reception strength detection unit to the portable computer is provided. On the other hand, the portable computer is provided with a wireless transmission output control unit that controls the transmission radio wave output based on the reception intensity notification signal from the reception intensity notification unit in the AC power source driven computer terminal. As a result, the transmission radio wave output from the computer terminal driven by the AC power source is set to the maximum value of the regulation, and by controlling the transmission radio wave output only for the portable computer, good data communication can be performed and the environment can be flexibly changed. Can respond.

A second embodiment will be described as a wireless communication control system in which the transmission radio wave output is controlled according to the transmission quality even during data communication. << Embodiment 2 >> FIG. 6 is a block diagram of the wireless communication control system. The system shown in the figure corresponds to the configuration of the computer terminal 102 shown in FIG. 4, and the configurations of the antenna 4 to the reception control unit 15 are the same as the system of FIG. In addition, the transmission quality control unit 16 uses the wireless reception interface 5
Based on the output of, the error rate of the radio wave received from the computer terminal of the other party is detected, and this error rate is
It has a function to increase the transmission radio wave output from its own computer terminal when it exceeds the preset specified value, and to lower the transmission radio wave output when the detected error rate is below the specified value. It is what

That is, the transmission quality control section 16 comprises an error rate detection section 16a and a transmission output control instruction section 16b. The error rate detection section 16a detects the error rate of the received radio wave and gives a transmission output control instruction. The unit 16b is configured to send a transmission output control instruction to the wireless transmission output control unit 9 based on the error rate detected by the error rate detection unit 16a.

Next, the operation of the wireless communication control system having the above configuration will be described. In wireless data communication, unlike wired data communication, changes in the environment greatly affect communication quality. Further, in a wireless LAN system, a computer terminal may move during data transfer, and when moving in a direction away from a communication partner, reception strength may deteriorate and a transfer error rate may increase. In this example, consider a case where the computer terminal 102 moves in a direction away from the computer terminal 101 during data transfer.

FIG. 7 shows these computer terminals 101,
3 is a sequence chart of transmission / reception operations of 102. First, when the link is established, the transmission output of each of the computer terminals 101 and 102 is controlled as described in the first embodiment.

After that, the data communication is started and data is being transferred between the computer terminals 101 and 102, and the transmission quality control section 16 checks for a data error occurrence notification (for example, a retransmission request) from the partner computer terminal for the transmitted data. . The transmission quality control unit 16 counts the transfer error rate (in the figure) within a fixed time, and when it reaches an error rate equal to or higher than a threshold value which is a preset specified value, the transmission quality control unit 9 instructs the wireless transmission output control unit 9 to do so. To increase the output (in the figure). After that, the transmission output of the data transmitted from the wireless transmission interface 12 is increased to operate to improve the transmission quality. As a result, since the transmission output at the computer terminal 102 becomes high, the reception strength at the computer terminal 101 side also becomes high, and the frequency of occurrence of data error becomes low.

The transmission quality control section 16 continuously checks the frequency of occurrence of data errors, and when the data recovers above the threshold value, instructs the radio transmission output control section 9 to reduce the transmission output. (In the figure). After that, the transmission output is controlled by the operation of the transmission quality control unit 16 so that a constant transmission quality is maintained. As described above, in the second embodiment, it is possible to ensure a certain transmission quality while following changes in the wireless transmission environment and without excessively increasing the transmission output.

In addition, when a sudden change in the environment occurs, the transmitted data may not be received by the partner computer terminal, and a timeout may occur in which a response signal for the transmitted data is not received. In this situation, it is conceivable that the other party's terminal moves in a direction away from the source computer terminal in a short time. In such cases,
An example in which the transmission quality control unit 16 detects a response timeout and thereby maximizes the wireless transmission output will be described as a third embodiment.

<Third Embodiment> FIG. 8 is a block diagram of the wireless communication control system. The system shown in the figure corresponds to the configuration of the computer terminal 102 in the first and second embodiments, and the configurations of the antenna 4 to the reception control unit 15 are similar to those in the first and second embodiments. Further, the transmission quality control unit 16 monitors the response time until the response signal is received from the partner computer terminal 101 with respect to the transmission signal from the computer terminal 102 of its own, and the response time is
When the preset time-out value is exceeded, control is performed so that the transmission radio wave output from the computer terminal 102 of its own is maximized.

Further, the transmission quality control unit 16 detects the error rate of the radio wave received from the partner computer terminal 101 after maximizing the transmission radio wave output, similarly to the transmission quality control unit 16 of the second embodiment. However, if the error rate exceeds a preset specified value, the radio wave output from the own computer terminal 102 is increased, and if the error rate is less than the specified value, the transmit radio wave output from the own computer terminal 102. The control is performed so as to lower.

That is, the transmission quality control unit 16 is composed of an error rate detection unit 16a, a transmission output control instruction unit 16b, and a timeout detection unit 16c. The timeout detection unit 16c detects a timeout when a response timeout is detected. The signal is sent to the transmission output control instructing unit 16b, and the transmission output control instructing unit 16b instructs the wireless transmission output control unit 9 to maximize the transmission radio wave output. The operations of the error rate detection unit 16a and the transmission output control instruction unit 16b are the same as those in the second embodiment.

Next, the operation of the wireless communication control system having the above configuration will be described. FIG. 9 is a sequence chart for explaining the operation of the third embodiment, and this sequence chart shows the sequence after the operation of the second embodiment shown in FIG. When the timeout detection unit 16c of the transmission quality control unit 16 detects a timeout (in the figure), the transmission output control instruction unit 16b sends a maximum radio wave output instruction to the wireless transmission output control unit 9 (in the figure). ). As a result, the subsequent data transmission is performed at the maximum output, the receiving sensitivity of the partner computer terminal 101 is improved, and the transmission quality is also improved.

After that, the transmission quality control similar to that of the second embodiment is performed as necessary. That is, if the wireless environment is stable, it is possible to reduce the transmission output at any time (in the figure) by the same operation as in the second embodiment, and suppress the power consumption. As described above, in the third embodiment, the response time until the response signal is received from the partner computer terminal 101 with respect to the transmission signal from the own computer terminal 102 is monitored, and when the time is out, the transmission from the own computer terminal 102 is performed. Since the radio wave output is maximized, it is possible to flexibly respond to sudden environmental changes.

In the third embodiment, as in the case of the first embodiment described above, only one of the computer terminals 101 and 102 may be configured to monitor the timeout of the response time. That is, the computer terminal that performs the time-out monitoring may be a battery-powered portable computer, and the other computer terminal may be an AC-powered computer that always sets the maximum transmission wave output.

In each of the above embodiments, the case where the wireless communication control system is applied to the wireless LAN system in which a plurality of computer terminals are present in the cell has been described, but the present invention is not limited to this configuration. As long as it is a system for performing data communication between at least two computer terminals, it can be applied in the same manner as each of the above embodiments.

[0044]

As described above in detail, according to the wireless communication control system of the present invention, one of the nodes checks the radio wave intensity received from the partner node,
This is notified to the other party, and the other party's node controls its own transmission output based on this notification. Therefore, even if the node is composed of a portable device such as a portable computer, It is possible to flexibly cope with environmental changes without impairing the characteristics.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment in a wireless communication control system of the present invention.

FIG. 2 is a configuration diagram of a wireless LAN to which the wireless communication control system of the present invention is applied.

FIG. 3 is a sequence chart illustrating the operation of the first embodiment in the wireless communication control system of the present invention.

FIG. 4 is a configuration diagram of a specific example of the first embodiment in the wireless communication control system of the present invention.

FIG. 5 is an explanatory diagram of another state in the wireless communication control system of the present invention.

FIG. 6 is a configuration diagram of a second embodiment in the wireless communication control system of the present invention.

FIG. 7 is an operation sequence chart of the second embodiment in the wireless communication control system of the present invention.

FIG. 8 is a configuration diagram of a third embodiment in the wireless communication control system of the present invention.

FIG. 9 is an operation sequence chart of the third embodiment in the wireless communication control system of the present invention.

[Explanation of symbols]

 1a reception strength detection unit 2a reception strength notification unit 3 wireless transmission output control unit 16 transmission quality control unit 101, 102 computer terminal (node)

Claims (5)

[Claims] 1. A wireless communication control system for performing data communication between nodes using wireless radio waves as a medium, wherein a wireless link establishment request destination node in the node is a wireless link establishment request source node of the node. When a request is received, a reception strength detection unit that detects the reception strength of the radio wave, and a reception strength detection unit that notifies the wireless link establishment request source node of the reception strength detected by the reception strength detection unit, The wireless communication control system, wherein the wireless link establishment request source node includes a wireless transmission output control unit that controls a transmission radio wave output based on a reception strength notification signal from the wireless link establishment request destination node. 2. In a wireless communication control system for performing data communication between nodes using wireless radio waves as a medium, when either one of a wireless link establishment request or a wireless link establishment confirmation response is received from a partner node, A reception strength detection unit that detects the reception strength of the radio wave, a reception strength detection unit that notifies the reception side detected by the reception strength detection unit to the partner node, and a reception strength notification signal from the communication connection partner A wireless communication control system comprising: a wireless transmission output control unit that controls a transmission radio wave output. 3. A wireless communication control system for performing data communication between nodes using wireless radio waves as a medium, detecting an error rate of a radio wave received from a partner node, and the detected error rate is a prescribed value set in advance. A transmission quality control unit is provided to increase the transmission radio wave output from the own node when the value exceeds the specified value and decrease the transmission radio wave output from the own node when the error rate is equal to or less than the specified value. A wireless communication control system. 4. A wireless communication control system for performing data communication between nodes using wireless radio waves as a medium, monitoring a response time until a response signal is received from a partner node with respect to a transmission signal from the own node, and the response time is concerned. However, when the preset timeout value is exceeded, the wireless communication control system is provided with a transmission quality control unit that maximizes the transmission radio wave output from the own node. 5. The wireless communication control system according to claim 4, wherein the transmission quality control unit detects the error rate of the radio wave received from the partner node after maximizing the transmission radio wave output from the own node, and If the detected error rate exceeds a preset specified value, increase the radio wave output from the own node, and if the error rate is below the specified value, decrease the transmit radio wave output from the own node. A wireless communication control system characterized by being configured to perform control.