JPH08204630A - Radio communication system - Google Patents

Abstract

PURPOSE: To uniformize a reception characteristic in a radio base station without giving effect onto carrier sensing. CONSTITUTION: A radio base station uses a reception section 13 to receive a radio signal from a radio terminal equipment and a reception power measurement section 14 measures reception power to discriminate a distance of the radio terminal equipment, a data generating circuit 15 generates data including terminal equipment distance information with the radio terminal equipment and a transmission section 16 sends the data. The radio terminal equipment uses a reception section 13 to receive data from the radio base station and to separate the terminal equipment distance information and usual data. A distance recognition section 24 recognizes a distance between the radio terminal equipment and the radio base station based on the terminal equipment distance information, and set a transmission speed of a transmission signal based on the recognized terminal equipment distance information. Then a transmission section 27 sends the data at the set transmission speed and the data are sent to the radio terminal equipment located at a remote position from the radio base station at a slower transmission speed than that of the radio terminal equipment located close to the radio base station.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication system for performing wireless communication between a plurality of wireless terminals and wireless base stations.

[0002]

2. Description of the Related Art Generally, in a wireless communication system of this type, the transmission characteristics deteriorate as the distance between a wireless terminal and a wireless base station increases. Therefore, a wireless signal transmitted from a wireless terminal located far from the wireless base station is less likely to be received by the wireless base station than a wireless signal transmitted from a wireless terminal located near the wireless base station. There's a problem.

In order to improve this near-far problem, there is a method (power control) of controlling the transmission power of a radio signal transmitted from a radio terminal. That is, in the case of the wireless communication system as shown in FIG. 8, the transmission power from the wireless terminal 2b closest to the wireless base station 1 is minimized and the transmission power from the wireless terminal 2a farthest from the wireless base station 1 is maximized. By performing power control as described above, the reception power from each of the wireless terminals 2a to 2c in the wireless base station 1 is made uniform. Wireless base station 1
By equalizing the received power in the wireless terminals 2, the wireless signals from the wireless terminals 2b located in the vicinity are not preferentially received, and the wireless terminals 2a to 2c are evenly wirelessly transmitted to the wireless base station 1. The communication is made to take place.

[0004]

However, in the above-described wireless communication system, power control may cause a problem in carrier sensing performed by the wireless terminals 2a to 2c prior to the start of communication. There is. That is, the power control is set so that the transmission power of the wireless terminal 2b closest to the wireless base station 1 becomes small, and when it is assumed that the wireless base station 1 and the wireless terminal 2b are in communication, the wireless terminal 2a At the start of communication, when attempting to perform carrier sense to check whether another wireless terminal is not communicating, since the transmission power from the wireless terminal 2b has been set low, There is a problem that the radio signal transmitted from the terminal 2b cannot be received, and accurate carrier sense cannot be performed.

The present invention has been made in view of the above points, and an object thereof is a wireless communication system for performing wireless communication between a plurality of wireless terminals and a wireless base station,
It is an object of the present invention to provide a wireless communication system that can make reception characteristics of wireless base stations uniform without affecting carrier sense.

[0006]

According to a first aspect of the present invention, in a wireless communication system for wireless communication between a plurality of wireless terminals and a wireless base station, the wireless base station receives a transmission signal from the wireless terminal. The receiving unit for receiving, the receiving power measuring unit for determining the distance to the wireless terminal by measuring the receiving power, the data generating unit for generating data including the terminal distance information in normal data, and the data generating unit. The wireless terminal comprises a transmitter for transmitting the generated data, and the wireless terminal receives the data and separates the terminal distance information and the normal data from the received data, and wirelessly detects the separated terminal distance information. A distance recognition unit that recognizes the distance between the terminal and the wireless base station, a transmission speed setting unit that sets the transmission speed of the transmission signal based on the recognized terminal distance information, and a data transmission unit that uses the set transmission speed. The wireless terminal located far from the wireless base station transmits data at a slower transmission speed than a wireless terminal near the wireless base station. .

According to a second aspect of the present invention, in the first aspect of the present invention, a radio base station is provided with a continuous transmission number setting section for setting the number of continuous transmissions of data based on the terminal distance information. The wireless terminal located far from the station is characterized in that the number of continuous data transmissions is set to be larger than that of the wireless terminal close to the station.

[0008]

According to a first aspect of the present invention, in a radio communication system for performing radio communication between a plurality of radio terminals and a radio base station,
In the wireless base station, the receiving unit receives the transmission signal from the wireless terminal, the receiving power measuring unit measures the received power to determine the distance to the wireless terminal, and the data generating unit determines the terminal distance information with the wireless terminal. Is generated, and the generated data is transmitted from the transmission unit.In the wireless terminal, the reception unit receives the data from the wireless base station, and at the same time receives the terminal distance information and the normal data from the received data. From the separated terminal distance information, the distance recognition unit recognizes the distance between the wireless terminal and the wireless base station, sets the transmission rate of the transmission signal based on the recognized terminal distance information, and sets the set transmission rate. Thus, the data is transmitted from the transmitting unit so that the wireless terminal existing far from the wireless base station transmits the data at a slower transmission speed than the wireless terminal near the wireless base station.

According to a second aspect of the present invention, in the first aspect of the present invention, the continuous transmission number setting unit sets the continuous transmission number of data based on the terminal distance information, and the data is set at a position far from the radio base station. The existing wireless terminals are designed to make the number of continuous data transmissions larger than that of the nearby wireless terminals.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a wireless base station according to an embodiment of a wireless communication system of the present invention, which includes an antenna 11, a wireless unit 12, a receiving unit 13, and a received power measuring unit 1.
4, a data generation unit 15, a transmission unit 16, a switch 17, and a speed reading unit 18. The wireless unit 12 mutually converts a wireless signal and an electric signal. The wireless unit 12 converts the wireless signal received via the antenna 11 into an electric signal and sends the electric signal to the receiving unit 13, and the electric signal from the transmitting unit 16 is wirelessly transmitted. It is converted into a signal and sent to the wireless terminal via the antenna 11. The reception unit 13 receives the signal from the wireless unit 12, and outputs it as a reception signal to the reception power measurement unit 14 and the data generation unit 15. The received power measuring unit 14 measures the power of the received signal. The data generation unit 15 generates data as shown in FIG. 2, and is a terminal indicating the distance from the wireless terminal that has transmitted the wireless signal, based on the reception power measured by the reception power measurement unit 14. The distance information and normal data information (transmission data) are attached with a header containing control information such as a packet start position. That is, the distance between the wireless base station and the wireless terminal that has transmitted the wireless signal can be determined according to the value of the received power.
For example, when the value of the received power is small, it is determined that the distance between the two is large, so that the terminal distance information is generated. The transmission unit 16 generates a transmission signal for the wireless terminal and sends it to the wireless unit 12. Switch 17
Is for switching the connection between the wireless unit 12, the receiving unit 13, and the transmitting unit 16. As will be described later, the speed reading unit 18 reads the transmission speed information of the transmission signal included in the data sent from the wireless terminal, returns the read result to the receiving unit, and sends it to the transmitting unit 16. Receiver 13
The transmission unit 16 performs the reception process and the transmission process based on the transmission speed information output from the speed reading unit 18.

FIG. 3 is a block diagram showing a schematic configuration of a wireless terminal according to an embodiment of the wireless communication system of the present invention. The antenna 21, the wireless unit 22, the receiving unit 23, the distance recognizing unit 24, the transmission rate setting. It includes a unit 25, a data generation unit 26, a transmission unit 27, and a switch 28. The wireless unit 22 mutually converts a wireless signal and an electric signal. The wireless unit 22 converts the wireless signal received via the antenna 21 into an electric signal and sends the electric signal to the receiving unit 23, and the electric signal from the transmitting unit 27 is wirelessly transmitted. The signal is converted into a signal and is transmitted via the antenna 21 to the wireless base station 1
To send to. The reception unit 23 receives the signal from the wireless unit 22, separates the terminal distance information and the normal data information (received data) from the received data, and outputs the terminal distance information to the distance recognition unit 24. It is a thing. The distance recognition unit 24 recognizes the distance between the wireless base station and the wireless terminal itself based on the terminal distance information separated and output by the reception unit 23. The transmission speed setting unit 25 inserts the speed information into the data generated by the data generation unit 26 according to the distance recognized by the distance recognition unit 24, and transmits the data generated by the data generation unit 26. The speed is set in the transmission unit 27. As shown in FIG. 4, the data is generated by inserting speed information between a header and normal data information (transmission data). The transmission speed is set so that the greater the distance recognized by the distance recognition unit 24, the slower it becomes. That is, the large distance means that the wireless signal transmitted from the wireless terminal itself is attenuated and a transmission error or the like occurs, which makes it difficult to be accurately transmitted to the wireless base station 1. Therefore, in this case, by decreasing the transmission speed of the transmission signal, the probability that a data transmission error will occur is reduced and the occurrence of a transmission error is reduced.

Next, the operation of this embodiment will be described. Now, as shown in FIG. 5, the wireless base station 1 has three wireless terminals 2a ...
Consider a case where the wireless terminal 2a is at the farthest position from the wireless base station 1 and the wireless terminal 2b is at the closest position to the wireless base station 1 in the wireless communication system trying to communicate with the wireless base station 2c. Each of the wireless terminals 2a to 2c first performs carrier sense and confirms that a communication path is secured, and then transmits a wireless signal. For example, when a wireless signal is transmitted after performing carrier sense from the wireless terminal 2b, the wireless base station 1 receives this wireless signal,
The reception power measurement unit 14 measures the reception power, and the data generation unit 15 generates the terminal distance information according to the value of the reception power and the data in which the header is added to the normal data information (transmission data) as one packet. To be done. And
This data is transmitted to the wireless terminal 2b. The wireless terminal 2b receives the data transmitted from the wireless base station 1, and the receiving unit 23 separates the data into terminal distance information and data information (received data). The terminal distance information is input to the distance recognition unit 24, and the distance between the wireless terminal 2b and the wireless base station 1 is recognized. Then, the transmission rate setting unit 25 sets the transmission rate according to this distance to the transmission unit 27. In the case of this embodiment, since the distance between the wireless terminal 2b and the wireless base station 1 is small,
A high transmission rate is set. In the transmission unit 27, the transmission signal of the data generated by the data generation unit 26 is transmitted to the radio base station 1 at the set high transmission rate. On the other hand, the data information is processed by the data generation unit 26, and then the data to be transmitted is generated and sent to the transmission unit 27. Here, as the data to be transmitted, as shown in FIG. 4, the transmission rate information set by the transmission rate setting unit 25 is included. Here, the wireless base station 1 receives signals with different transmission rates from each wireless terminal. For example, as a transmission signal from the wireless terminal, a header of data and a portion of speed information shown in FIG. Only, if the transmission rate is not changed and the transmission rate is always constant, the wireless base station 1 can read the header and the rate information portion.
After reading the transmission rate information and recognizing the transmission rate, the reception process and the transmission process may be performed based on the transmission rate information.

According to this embodiment, since the radio signals from the radio terminals 2a to 2c are transmitted at the transmission rate according to the distance to the radio base station 1, the reception characteristics in the radio base station 1 can be made uniform. Can be done. In addition, the wireless terminals 2a to
Since the transmission power of the radio signal from the wireless terminal 2c is not changed according to the distance between the wireless terminals 2a to 2c and the wireless base station 1, the carrier sensing of the wireless terminals 2a to 2c can be performed accurately. is there.

FIG. 6 is a block diagram showing the schematic arrangement of a radio terminal according to another embodiment of the radio communication system of the present invention. In the radio terminal shown in FIG. 3, a continuous transmission number setting unit 29 is added. It is a thing. Continuous transmission number setting unit 29
Is for setting the number of continuous transmissions of the transmission signal based on the distance information output from the distance recognition unit 24. That is, as shown in FIG. 7, by increasing the number of continuous transmissions in the case of the wireless terminal 2a having a long distance from the wireless base station 1, and by decreasing the number of continuous transmissions in the case of a short wireless terminal 2b, It is intended to further improve the uniformity of reception characteristics in the base station 1.

In this embodiment, the wireless terminals 2a-2c are used.
In the above, the packet length setting unit 25 and the continuous transmission number setting unit 29 are used together, but it goes without saying that the continuous transmission number setting unit 29 alone can achieve uniform reception characteristics in the radio base station 1.

[0016]

As described above, according to the first aspect of the invention, in a wireless communication system in which wireless communication is performed between a plurality of wireless terminals and a wireless base station, in the wireless base station, the receiving section from the wireless terminal To receive the transmission signal of, to measure the received power in the received power measurement unit to determine the distance to the wireless terminal,
The data generation unit generates data including the terminal distance information with the wireless terminal, and the generated data is transmitted from the transmission unit. In the wireless terminal, the reception unit receives and receives the data from the wireless base station. Terminal distance information and normal data are separated from the data, the distance between the wireless terminal and the wireless base station is recognized by the distance recognition unit from the separated terminal distance information,
The transmission rate of the transmission signal is set based on the recognized terminal distance information, the data is transmitted from the transmission section at the set transmission rate, and the wireless terminal located far from the wireless base station is close. Since the data is transmitted at a transmission speed slower than that of the wireless terminal, in a wireless communication system that performs wireless communication between a plurality of wireless terminals and the wireless base station, the wireless base station can be used without affecting carrier sense. A wireless communication system capable of equalizing the reception characteristics in the wireless communication system can be provided.

According to a second aspect of the present invention, in the first aspect of the present invention, the continuous transmission number setting unit sets the continuous transmission number of data based on the terminal distance information, and the data is transmitted to a position far from the radio base station. Since the existing wireless terminals are designed to make the number of continuous data transmissions larger than that of the nearby wireless terminals, it is possible to further improve the uniformity of the reception characteristics in the wireless base station.

[Brief description of drawings]

[0018]

FIG. 1 is a block diagram showing a schematic configuration of a wireless base station according to an embodiment of a wireless communication system of the present invention.

[0019]

FIG. 2 is a data format according to the above.

[0020]

FIG. 3 is a block diagram showing a schematic configuration of a wireless terminal according to an embodiment of a wireless communication system of the present invention.

[0021]

FIG. 4 is a data format according to the above.

[0022]

FIG. 5 is a schematic diagram for explaining an operation according to an embodiment of a wireless communication system of the present invention.

[0023]

FIG. 6 is a block diagram showing a schematic configuration of a wireless terminal according to another embodiment of the wireless communication system of the present invention.

[0024]

FIG. 7 is a schematic diagram for explaining an operation according to another embodiment of the wireless communication system of the present invention.

[0025]

FIG. 8 is a schematic diagram for explaining an operation of a conventional wireless communication system.

[0026]

[Description of Reference Signs] 1 wireless base station 2a to 2c wireless terminal 11 antenna 12 wireless unit 13 receiving unit 14 received power measuring unit 15 data generating unit 16 transmitting unit 17 switch 18 speed reading unit 21 antenna 22 wireless unit 23 receiving unit 24 distance Recognition unit 25 Transmission rate setting unit 26 Data generation unit 27 Transmission unit 28 Switch 29 Continuous transmission number setting unit

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 3, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Detailed explanation of the invention

[Correction method] Change

[Correction content]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication system for performing wireless communication between a plurality of wireless terminals and wireless base stations.

[0002]

2. Description of the Related Art Generally, in a wireless communication system of this type, the transmission characteristics deteriorate as the distance between a wireless terminal and a wireless base station increases. Therefore, a wireless signal transmitted from a wireless terminal located far from the wireless base station is less likely to be received by the wireless base station than a wireless signal transmitted from a wireless terminal located near the wireless base station. There's a problem.

In order to improve this near-far problem, there is a method (power control) of controlling the transmission power of a radio signal transmitted from a radio terminal. That is, in the case of the wireless communication system as shown in FIG. 8, the transmission power from the wireless terminal 2b closest to the wireless base station 1 is minimized and the transmission power from the wireless terminal 2a farthest from the wireless base station 1 is maximized. By performing power control as described above, the reception power from each of the wireless terminals 2a to 2c in the wireless base station 1 is made uniform. Wireless base station 1
By equalizing the received power in the wireless terminals 2, the wireless signals from the wireless terminals 2b located in the vicinity are not preferentially received, and the wireless terminals 2a to 2c are evenly wirelessly transmitted to the wireless base station 1. The communication is made to take place.

[0004]

However, in the above-described wireless communication system, power control may cause a problem in carrier sensing performed by the wireless terminals 2a to 2c prior to the start of communication. There is. That is, the power control is set so that the transmission power of the wireless terminal 2b closest to the wireless base station 1 becomes small, and when it is assumed that the wireless base station 1 and the wireless terminal 2b are in communication, the wireless terminal 2a At the start of communication, if a carrier sense is performed to check whether or not another wireless terminal is communicating, the wireless terminal 2b has set the transmission power to a low value, and therefore the wireless communication is There is a problem that the radio signal transmitted from the terminal 2b cannot be received, and accurate carrier sense cannot be performed.

The present invention has been made in view of the above points, and an object thereof is a wireless communication system for performing wireless communication between a plurality of wireless terminals and a wireless base station,
It is an object of the present invention to provide a wireless communication system that can make reception characteristics of wireless base stations uniform without affecting carrier sense.

[0006]

According to a first aspect of the present invention, in a wireless communication system for wireless communication between a plurality of wireless terminals and a wireless base station, the wireless base station receives a transmission signal from the wireless terminal. The receiving unit for receiving, the receiving power measuring unit for determining the distance to the wireless terminal by measuring the receiving power, the data generating unit for generating data including the terminal distance information in normal data, and the data generating unit. The wireless terminal comprises a transmitter for transmitting the generated data, and the wireless terminal receives the data and separates the terminal distance information and the normal data from the received data, and wirelessly detects the separated terminal distance information. A distance recognition unit that recognizes the distance between the terminal and the wireless base station, a transmission speed setting unit that sets the transmission speed of the transmission signal based on the recognized terminal distance information, and a data transmission unit that uses the set transmission speed. The wireless terminal located far from the wireless base station transmits data at a slower transmission speed than a wireless terminal near the wireless base station. .

According to a second aspect of the present invention, in the first aspect of the present invention, a radio base station is provided with a continuous transmission number setting section for setting the number of continuous transmissions of data based on the terminal distance information. The wireless terminal located far from the station is characterized in that the number of continuous data transmissions is set to be larger than that of the wireless terminal close to the station.

[0008]

According to a first aspect of the present invention, in a radio communication system for performing radio communication between a plurality of radio terminals and a radio base station,
In the wireless base station, the receiving unit receives the transmission signal from the wireless terminal, the receiving power measuring unit measures the received power to determine the distance to the wireless terminal, and the data generating unit determines the terminal distance information with the wireless terminal. Is generated, and the generated data is transmitted from the transmission unit.In the wireless terminal, the reception unit receives the data from the wireless base station, and at the same time receives the terminal distance information and the normal data from the received data. From the separated terminal distance information, the distance recognition unit recognizes the distance between the wireless terminal and the wireless base station, sets the transmission rate of the transmission signal based on the recognized terminal distance information, and sets the set transmission rate. Thus, the data is transmitted from the transmitting unit so that the wireless terminal existing far from the wireless base station transmits the data at a slower transmission speed than the wireless terminal near the wireless base station.

According to a second aspect of the present invention, in the first aspect of the present invention, the continuous transmission number setting unit sets the continuous transmission number of data based on the terminal distance information, and the data is set at a position far from the radio base station. The existing wireless terminals are designed to make the number of continuous data transmissions larger than that of the nearby wireless terminals.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a wireless base station according to an embodiment of a wireless communication system of the present invention, which includes an antenna 11, a wireless unit 12, a receiving unit 13, and a received power measuring unit 1.
4, a data generation unit 15, a transmission unit 16, a switch 17, and a speed reading unit 18. The wireless unit 12 mutually converts a wireless signal and an electric signal. The wireless unit 12 converts the wireless signal received via the antenna 11 into an electric signal and sends the electric signal to the receiving unit 13, and the electric signal from the transmitting unit 16 is wirelessly transmitted. It is converted into a signal and sent to the wireless terminal via the antenna 11. The reception unit 13 receives the signal from the wireless unit 12, and outputs it as a reception signal to the reception power measurement unit 14 and the data generation unit 15. The received power measuring unit 14 measures the power of the received signal. The data generation unit 15 is for generating data as shown in FIG. 2, and is a terminal that indicates the distance from the wireless terminal that has transmitted the wireless signal, based on the reception power measured by the reception power measurement unit 14. The distance information and normal data information (transmission data) are attached with a header containing control information such as a packet start position. That is, the distance between the wireless base station and the wireless terminal that has transmitted the wireless signal can be determined according to the value of the received power.
For example, when the value of the received power is small, it is determined that the distance between the two is large, so that the terminal distance information is generated. The transmission unit 16 generates a transmission signal for the wireless terminal and sends it to the wireless unit 12. Switch 17
Is for switching the connection between the wireless unit 12, the receiving unit 13, and the transmitting unit 16. As described later, the speed reading unit 18 reads the transmission speed information of the transmission signal included in the data sent from the wireless terminal, returns the read result to the receiving unit, and sends the read result to the transmitting unit 16. Receiver 13
The transmission unit 16 performs the reception process and the transmission process based on the transmission speed information output from the speed reading unit 18.

FIG. 3 is a block diagram showing a schematic configuration of a wireless terminal according to an embodiment of the wireless communication system of the present invention. The antenna 21, the wireless unit 22, the receiving unit 23, the distance recognizing unit 24, the transmission rate setting. It includes a unit 25, a data generation unit 26, a transmission unit 27, and a switch 28. The wireless unit 22 mutually converts a wireless signal and an electric signal. The wireless unit 22 converts the wireless signal received via the antenna 21 into an electric signal and sends the electric signal to the receiving unit 23, and the electric signal from the transmitting unit 27 is wirelessly transmitted. The signal is converted into a signal and is transmitted via the antenna 21 to the wireless base station 1
To send to. The reception unit 23 receives the signal from the wireless unit 22, separates the terminal distance information and the normal data information (received data) from the received data, and outputs the terminal distance information to the distance recognition unit 24. It is a thing. The distance recognition unit 24 recognizes the distance between the wireless base station and the wireless terminal itself based on the terminal distance information separated and output by the reception unit 23. The transmission speed setting unit 25 inserts the speed information into the data generated by the data generation unit 26 according to the distance recognized by the distance recognition unit 24, and transmits the data generated by the data generation unit 26. The speed is set in the transmission unit 27. As shown in FIG. 4, the data is generated by inserting speed information between a header and normal data information (transmission data). The transmission speed is set so that the greater the distance recognized by the distance recognition unit 24, the slower it becomes. That is, the large distance means that the radio signal transmitted from the own radio terminal is attenuated and a transmission error or the like occurs, which makes it difficult to be accurately transmitted to the radio base station 1. Therefore, in this case, by decreasing the transmission speed of the transmission signal, the probability that a data transmission error will occur is reduced and the occurrence of a transmission error is reduced.

Next, the operation of this embodiment will be described. Now, as shown in FIG. 5, the wireless base station 1 has three wireless terminals 2a ...
Consider a case where the wireless terminal 2a is at the farthest position from the wireless base station 1 and the wireless terminal 2b is at the closest position to the wireless base station 1 in the wireless communication system trying to communicate with the wireless base station 2c. Each of the wireless terminals 2a to 2c first performs carrier sense and confirms that a communication path is secured, and then transmits a wireless signal. For example, when a wireless signal is transmitted after performing carrier sense from the wireless terminal 2b, the wireless base station 1 receives this wireless signal,
The reception power measurement unit 14 measures the reception power, and the data generation unit 15 generates the terminal distance information according to the value of the reception power and the data in which the header is added to the normal data information (transmission data) as one packet. To be done. And
This data is transmitted to the wireless terminal 2b. The wireless terminal 2b receives the data transmitted from the wireless base station 1, and the receiving unit 23 separates the data into terminal distance information and data information (received data). The terminal distance information is input to the distance recognition unit 24, and the distance between the wireless terminal 2b and the wireless base station 1 is recognized. Then, the transmission rate setting unit 25 sets the transmission rate according to this distance to the transmission unit 27. In the case of this embodiment, since the distance between the wireless terminal 2b and the wireless base station 1 is small,
A high transmission rate is set. In the transmission unit 27, the transmission signal of the data generated by the data generation unit 26 is transmitted to the radio base station 1 at the set high transmission rate. On the other hand, the data information is processed by the data generation unit 26, and then the data to be transmitted is generated and sent to the transmission unit 27. Here, as the data to be transmitted, as shown in FIG. 4, the transmission rate information set by the transmission rate setting unit 25 is included. Here, the wireless base station 1 receives signals with different transmission rates from each wireless terminal. For example, as a transmission signal from the wireless terminal, a header of data and a portion of speed information shown in FIG. Only, if the transmission rate is not changed and the transmission rate is always constant, the wireless base station 1 can read the header and the rate information portion.
After reading the transmission rate information and recognizing the transmission rate, the reception process and the transmission process may be performed based on the transmission rate information.

According to this embodiment, since the radio signals from the radio terminals 2a to 2c are transmitted at the transmission rate according to the distance to the radio base station 1, the reception characteristics in the radio base station 1 can be made uniform. Can be done. In addition, the wireless terminals 2a to
Since the transmission power of the radio signal from the wireless terminal 2c is not changed according to the distance between the wireless terminals 2a to 2c and the wireless base station 1, the carrier sensing of the wireless terminals 2a to 2c can be performed accurately. is there.

FIG. 6 is a block diagram showing the schematic arrangement of a radio terminal according to another embodiment of the radio communication system of the present invention. In the radio terminal shown in FIG. 3, a continuous transmission number setting unit 29 is added. It is a thing. Continuous transmission number setting unit 29
Is for setting the number of continuous transmissions of the transmission signal based on the distance information output from the distance recognition unit 24. That is, as shown in FIG. 7, by increasing the number of continuous transmissions in the case of the wireless terminal 2a having a long distance from the wireless base station 1, and by decreasing the number of continuous transmissions in the case of a short wireless terminal 2b, It is intended to further improve the uniformity of reception characteristics in the base station 1.

In this embodiment, the wireless terminals 2a-2c are used.
In the above, the packet length setting unit 25 and the continuous transmission number setting unit 29 are used together, but it goes without saying that the continuous transmission number setting unit 29 alone can achieve uniform reception characteristics in the radio base station 1.

[0016]

As described above, according to the first aspect of the invention, in a wireless communication system in which wireless communication is performed between a plurality of wireless terminals and a wireless base station, in the wireless base station, the receiving section from the wireless terminal To receive the transmission signal of, to measure the received power in the received power measurement unit to determine the distance to the wireless terminal,
The data generation unit generates data including the terminal distance information with the wireless terminal, and the generated data is transmitted from the transmission unit. In the wireless terminal, the reception unit receives and receives the data from the wireless base station. Terminal distance information and normal data are separated from the data, the distance between the wireless terminal and the wireless base station is recognized by the distance recognition unit from the separated terminal distance information,
The transmission rate of the transmission signal is set based on the recognized terminal distance information, the data is transmitted from the transmission section at the set transmission rate, and the wireless terminal located far from the wireless base station is close. Since the data is transmitted at a transmission speed slower than that of the wireless terminal, in a wireless communication system that performs wireless communication between a plurality of wireless terminals and the wireless base station, the wireless base station can be used without affecting carrier sense. A wireless communication system capable of equalizing the reception characteristics in the wireless communication system can be provided.

According to a second aspect of the present invention, in the first aspect of the present invention, the continuous transmission number setting unit sets the continuous transmission number of data based on the terminal distance information, and the data is transmitted to a position far from the radio base station. Since the existing wireless terminals are designed to make the number of continuous data transmissions larger than that of the nearby wireless terminals, it is possible to further improve the uniformity of the reception characteristics in the wireless base station.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a wireless base station according to an embodiment of a wireless communication system of the present invention.

FIG. 2 is a data format according to the above.

FIG. 3 is a block diagram showing a schematic configuration of a wireless terminal according to an embodiment of a wireless communication system of the present invention.

FIG. 4 is a data format according to the above.

FIG. 5 is a schematic diagram for explaining an operation according to an embodiment of a wireless communication system of the present invention.

FIG. 6 is a block diagram showing a schematic configuration of a wireless terminal according to another embodiment of the wireless communication system of the present invention.

FIG. 7 is a schematic diagram for explaining an operation according to another embodiment of the wireless communication system of the present invention.

FIG. 8 is a schematic diagram for explaining an operation of a conventional wireless communication system.

[Description of Reference Signs] 1 wireless base station 2a to 2c wireless terminal 11 antenna 12 wireless unit 13 receiving unit 14 received power measuring unit 15 data generating unit 16 transmitting unit 17 switch 18 speed reading unit 21 antenna 22 wireless unit 23 receiving unit 24 distance Recognition unit 25 Transmission rate setting unit 26 Data generation unit 27 Transmission unit 28 Switch 29 Continuous transmission number setting unit

Claims (2)

[Claims] 1. In a wireless communication system for performing wireless communication between a plurality of wireless terminals and a wireless base station, the wireless base station includes:
A reception unit that receives a transmission signal from a wireless terminal, a reception power measurement unit that determines the distance to the wireless terminal by measuring the reception power, and a data generation that generates data including terminal distance information in normal data And a transmission unit that transmits the data generated by the data generation unit.
A receiving unit that receives the data and separates the terminal distance information and the normal data from the received data, a distance recognition unit that recognizes the distance between the wireless terminal and the wireless base station from the separated terminal distance information, and a recognition unit. A transmission rate setting unit for setting the transmission rate of the transmission signal based on the terminal distance information,
A wireless terminal that is equipped with a transmission unit that transmits data at a set transmission rate, and a wireless terminal that is located far from the wireless base station transmits data at a lower transmission rate than a wireless terminal that is close to the wireless base station. A wireless communication system. 2. A wireless terminal further comprising a continuous transmission number setting unit for setting the number of times of continuous transmission of data based on the terminal distance information, and the wireless terminal located far from the wireless base station is close to the wireless terminal. The wireless communication system according to claim 1, wherein the number of continuous data transmissions is set to be larger than that of the wireless communication system.