JP2008206171A - Radio communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten a transmission time for information transmission among a plurality of radio stations in a radio communication system which is comprised of the plurality of radio stations capable of changing a transmission rate, and in which information is simultaneously transmitted from one radio station to the other plurality of radio stations. <P>SOLUTION: Each of radio stations transmits a line quality measuring signal prior to starting transmitting information, determines a transmission rate available for transmission with each of the other radio stations from a line quality measuring signal received from the other radio stations, transmits a rate enabling transmission with all the other radio stations to the other radio stations using a rate notification signal, stores a communication velocity between stations from a velocity notification signal received from the other radio stations, determines a communication route and a transmission rate for transmission to all the receiver party stations by reading the inter-station communication velocity when starting transmitting information, transmits transmission information at the transmission rate after adding information about the communication route thereto, and retransmits the received transmission information in a case where the present station is designated as a relay station by the communication route information received from the other radio stations. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radio communication system, and more particularly, to a radio communication system in which a transmission time for information transmission between a plurality of radio stations is shortened.

FIG. 1 shows an example of the geographical arrangement of radio stations in a radio communication system. In FIG. 1, wireless stations are represented by A, B, C, D, and E.
For example, each of the radio stations A to E can change the transmission speed by changing the multi-value number of the modulation method, for example, 4 kinds of 1 Mbps, 500 kbps, 250 kbps, and 125 kbps, and the optimum transmission depending on the line quality. It is a device that can communicate at a selected speed.

  Such radio stations A to E are arranged as shown in FIG. 1, and it is possible to transmit at 1 Mbps from the distance between the stations between AB, AC, CD, CE, and DE. It is assumed that there is a positional relationship between AD and BC that can be transmitted only at 250 kbps from the distance between the stations, and between AEs that can only be transmitted at 125 kbps from the distance between the stations.

  In the system having such an arrangement, if the same information is to be transmitted from the wireless station A to all the other stations B to E at the same time, in the conventional method, the transmission rate between the AEs that are the farthest away is the same. It is necessary to modulate and transmit at a certain 125 kbps. Also, when transmitting from the wireless station A to the three stations B, C, and D excluding the wireless station E, the transmission must be performed at 250 kbps.

JP-A-10-294690

As described above, conventionally, information transmission between a plurality of wireless stations may become inefficient, and it has been required to improve the efficiency.
The present invention has been made in view of such conventional circumstances, and an object of the present invention is to provide a wireless communication system capable of reducing the transmission time of information transmission between a plurality of wireless stations and improving efficiency. And

In order to achieve the above object, in the present invention, in a wireless communication system configured with a plurality of wireless stations capable of changing a transmission rate, one wireless station transmits information to a plurality of other wireless stations simultaneously. The configuration is as follows.
That is, each radio station transmits a channel quality measurement signal before starting transmission of information, a means for receiving a channel quality measurement signal from another radio station, and the received channel quality measurement signal. Means for determining a transmission rate that can be used for transmission with each other wireless station based on the transmission rate, and a transmission rate between all other wireless stations based on the determination result ( (Transmission rate) by means of a speed notification signal to other wireless stations, means for receiving a speed notification signal transmitted from another wireless station, and communication between stations based on the received speed notification signal Means for storing the speed (transmission speed), and communication path and transmission that can read out the stored inter-station communication speed (for example, most efficiently) and transmit it to all the receiving counterpart stations when information transmission starts. Means to determine the speed, Means for adding information on the determined communication path to information and transmitting at the determined transmission rate; means for receiving transmission information with communication path information added from another radio station; and Means for retransmitting the received transmission information when the own station is designated as a relay station based on communication path information.
Therefore, it is possible to shorten the transmission time of information transmission between a plurality of radio stations and to improve efficiency.

In the present invention, as a configuration example, a wireless communication system has the following configuration.
That is, transmission / reception of the line quality measurement signal and the speed notification signal is performed when the system is started up and at regular intervals.
Therefore, when the system is started up, the inter-station communication speed can be set according to the arrangement of a plurality of radio stations at that time, and the arrangement is changed due to movement of one or more radio stations. Even in this case, the communication speed between stations can be set at regular intervals according to the arrangement at that time, and efficient information transmission can always be realized.

In the present invention, as a configuration example, a wireless communication system has the following configuration.
That is, the radio channel used for transmission from the information source is different from the radio channel used for relay transmission.
Therefore, by providing different radio channels as a radio channel used for transmission from a radio station that transmits information (first, not for relay) and a radio channel used for relay transmission from a radio station that relays the information. For example, the probability of collision of transmission signals can be reduced, and it is possible to always use different radio channels for information transmission and relay transmission.

  As described above, according to the present invention, the inter-station communication speed is determined according to the channel quality based on the arrangement of a plurality of radio stations, and the communication path and transmission speed at the time of information transmission are determined based on the inter-station communication speed. Since the other station relays information transmission between the information transmission station and the destination station when necessary, information transmission between a plurality of wireless stations can be efficiently performed. .

Embodiments according to the present invention will be described with reference to the drawings.
In the wireless communication system of this example, a plurality of wireless stations A to E are arranged in a geographically dispersed manner as shown in FIG. 1, and each station transmits the same information all at once to a plurality of other stations. In this example, efficient transmission is realized.
FIG. 2 shows a configuration example of the communication apparatus of this example used as each of the radio stations A to E.
The communication apparatus of this example includes a transmission information memory 1, a communication control unit 2, a transmission unit 3, a transmission / reception switch (transmission / reception SW) 4, an antenna 5, a reception unit 6, a line quality determination unit 7, a speed A notification signal unit 8, a reception information memory 9, a relay designation determination unit 10, an inter-station speed memory 11, and a speed / communication path determination unit 12 are provided.

First, a communication procedure performed by the communication apparatus of this example is shown.
In this example, before starting information transmission in the system, each of the radio stations A to E exchanges signals for determining a transmission rate that can be used for transmission between the stations. Specifically, first, each of the stations A to E transmits a line quality measurement signal for measuring the transmission line quality between the stations and determining the transmission rate. Each station A to E receives channel quality measurement signals from all other stations, measures the channel quality (for example, S / N), and determines the transmission rate from the quality measurement result. After the transmission of the signal for measuring the line quality of all the stations is completed, each of the stations A to E transmits a transmission possible speed between the own station and all the other stations as a speed notification signal. Each of the stations A to E receives speed notification signals from all other stations and accumulates them in a memory (inter-station speed memory) as inter-station speed information.

The station that starts information transmission determines the most efficient communication path for all destination stations and the transmission speed when using the path from the contents of the inter-station speed memory. Next, the slowest transmission speed among the transmission speeds for all the destination stations is adopted as the information transmission speed, and information is transmitted at that speed. Further, as the content of the transmission signal, the information to be transmitted is added with a signal indicating the communication path for each destination station.
The station that has received the information performs a predetermined process using the received information as information addressed to itself, and at the same time determines whether or not the station is designated as a relay station to another station by the communication path information. If the local station is designated as a relay station, the received information is retransmitted.

  As a specific example using such a transmission method, when the same information is transmitted from the wireless station A to all the other stations B to E, for example, in the example of FIG. By using it as a relay station for E, transmission at 1 Mbps can be used for both transmission from the wireless station A and relay transmission from the wireless station C. Therefore, the wireless station A transmits a signal at 1 Mbps in which the communication path information specifying the wireless station C as a relay station for the wireless stations D and E is added to the transmission information. The wireless station C is 1 Mbps based on the specification. Perform relay transmission with. As a result, transmission for all stations can be performed efficiently.

FIGS. 3A to 3C show examples of signal formats to be transmitted.
FIG. 3A shows an example of a line quality measurement signal.
The channel quality measurement signal in this example is modulated at the slowest transmission rate, and includes a transmission station address and a quality measurement code for identifying the transmission station.
The quality measurement code is a predetermined code sequence, and is used to measure the S / N of the received signal by obtaining a correlation value between the signal received at the receiving station and the correct code sequence stored in advance. . As another configuration example, when an equalizer is used at the receiving station, the S / N can be measured based on the equalization error.

FIG. 3B shows an example of the speed notification signal.
The speed notification signal in this example is composed of a transmission station address and an inter-station speed signal.
The inter-station speed signal is a signal that individually indicates the transmittable speed between the own station and all other stations, and by receiving this, each station transmits it to all other stations. It is possible to detect and know the transmission speed between the stations. Further, by receiving the speed notification signals from all the stations, it is possible to know the mutual transmission speed for all the stations in the system.
Here, as the transmission possible speed between the stations, notifications of speeds from two opposing stations are gathered. For example, in order to ensure the reliability of information transmission, A configuration in which the lower speed is selected can be used.

FIG. 3C shows an example of a signal for transmitting transmission information.
The signal for transmitting the transmission information in this example includes a transmission station address, a communication routing signal, and transmission information.
The communication route designation signal in this example is a signal that designates the relay station address and the destination address ahead of the relay station when relay is required. Whether the receiving station needs to be the relay station by this designation. If the relay is necessary, the received information is retransmitted.
The transmission information part is the information itself to be transmitted.

  Here, the exchange of the line quality measurement signal and the speed notification signal among all the stations constituting the system is performed, for example, at the time of starting the system. Even when the positional relationship of the radio stations changes due to, for example, information on the route and transmission speed necessary for transmission can always be kept up-to-date. Such processing at regular intervals can be realized, for example, by having each station have a clock and adjusting the clock every time both signals are exchanged to determine the next exchange time.

Next, processing performed by the communication apparatus of this example shown in FIG. 2 will be described.
The line quality determination unit 7 measures the line quality from the line quality measurement signal received from the other station to determine the transmittable speed, and the speed notification signal unit 8 indicates the speed between all stations. Accumulated as speed notification information.
The inter-station speed memory 11 stores the contents of the speed notification signal received from the other station in the memory as the inter-station speed between all stations, and the speed / communication path determination unit 12 For the destination, the most efficient communication path and the transmission speed when the path is used are obtained, and the slowest transmission speed is selected as the speed used for transmission.
The relay designation determination unit 10 determines whether or not the own station is designated as a relay station from the communication path information in the received information signal.

The transmission information memory 1 stores transmission information (transmission information) in the memory.
The communication control unit 2 performs various types of communication control, for example, control for transmitting a speed notification signal based on speed notification information from the speed notification signal unit 8, speed and communication from the speed communication path determination unit 12. Based on the determination result of the route, when the control for transmitting the transmission information from the transmission information memory 1 or the relay designation determination unit 10 determines to perform relay transmission, the speed communication route determination unit 12 Based on the speed, control for retransmitting the reception information from the reception information memory 9 is performed.

The transmission unit 3 is controlled by the communication control unit 2, performs transmission processing on the transmission signal, and wirelessly transmits the signal from the antenna 5 via the transmission / reception switch 4.
The transmission / reception switch 4 performs switching to use one antenna 5 by switching between transmission and reception.
The receiving unit 6 inputs a signal wirelessly received by the antenna 5 through the transmission / reception switch 4 and performs reception processing. For example, the receiving unit 6 outputs a line quality measurement signal to the line quality determining unit 7 and transmits a speed notification signal between the stations. It outputs to the speed memory 11 and outputs a signal for transmitting the transmission information to the reception information memory 9 and the relay designation determination unit 10.
The reception information memory 9 stores reception information (transmission information) in the memory.

When the system is started up and the route is updated, the communication control unit 2 generates a line quality measurement signal, modulates the signal by the transmission unit 3, converts it to a radio frequency, and transmits it through the transmission / reception switch 4 and the antenna 5. As the modulation method, the method with the slowest modulation speed is used.
In the transmission of the speed notification signal, the line quality measurement signal from all other stations is received and the transmission speed between the local station and all other stations is obtained by the quality judgment, and then the speed notification is sent. It is read from the signal memory (in this example, the memory of the speed notification signal unit 8) and transmitted. As the modulation method, the method with the slowest modulation speed is used.
In transmission information transmission, the communication path and transmission speed are determined from the contents and destination of the inter-station speed memory 11, and the communication control unit 2 adds communication path information (communication path designation signal) to the transmission information based on the determination. Is modulated by the transmission unit 3 and transmitted. As the modulation speed, a speed system determined together with the communication path is used.

In reception, a received signal is received and demodulated through the antenna 5, the transmission / reception switch 4, and the receiving unit 6. Here, the modulation method is automatically determined by, for example, an identification code added to the received signal, and demodulated by a method corresponding to the input. The type of signal is also determined by the identification code.
In reception of the signal for channel quality measurement, the received signal is obtained by the channel quality determination unit 7 with respect to the signal of the quality measurement code, and a correlation value with a correct code string is obtained. / N is calculated, and the transmission speed that can be transmitted by the S / N is determined, and this is stored as a speed notification signal in the speed notification signal unit 8 in pairs with the address of the transmitting station (transmission station of the line quality measurement signal). Is done.
In receiving the speed notification signal, the received inter-station speed is stored in the inter-station speed memory 11 in pairs with the address of the transmitting station (the transmitting station of the speed notification signal). The stored inter-station speed is read when transmission information is transmitted, and is used to determine the communication path and transmission speed for the destination of the information.

Upon reception of the transmission information signal, the relay designation determination unit 10 determines whether or not the own station is designated as a relay station from the communication route designation signal in the signal, and is designated as the relay station. In this case, a code indicating that relaying is necessary and a relay destination address are stored in the memory. Transmission information other than the communication path designation signal is accumulated in the reception information memory 9, subjected to predetermined processing, and output to the outside.
When the transmission information signal is received, if it is determined that the local station is designated as a relay station, the transmission of the transmission information signal is started when the transmission information signal is received, and the information is received in the communication routing signal portion. The relay destination address is entered, and the transmission information received from the reception information memory 9 is read and transmitted. As a modulation method, the transmission possible speed between the own station and the relay destination station is read from the inter-station speed memory 11, and the speed method is used.
As the relay destination address, for example, the address of the next station of the own station can be used based on the communication path included in the communication path designation signal added to the received transmission information signal. Or it may be a further relay station.

  Here, in the transmission method of this example, as an example, a single wireless channel can be realized in a time-division form for the original transmission information transmission (not relaying) and the relay transmission information transmission. However, as another example, if the original transmission information transmission and the relay transmission information transmission are transmitted using different wireless channels using two wireless channels, information transmission is performed continuously. As a result, it is possible to reduce the collision of transmissions of a plurality of stations in the relay, and more efficient transmission is possible.

As described above, in this example, in a wireless communication system configured with a plurality of wireless stations capable of changing the transmission speed, one of the stations simultaneously transmits information to the other plurality of stations. Before the start of transmission, all stations that make up the system transmit a signal for channel quality measurement, and all stations can be used for transmission with each other station by a signal for measuring the channel quality from other stations The transmission speed is determined as a speed notification signal to all other stations, and all stations receive the speed notification signal transmitted from the other station. The communication speed is stored as an inter-station communication speed, and each station reads the inter-station communication speed at the start of information transmission, determines the communication path and transmission speed that can be transmitted to all receiving partner stations most efficiently, and transmits this communication path to the transmission information. Is sent at the determined transmission rate. In the station which has received this, When the own station is specified to the relay in the communication path information, it retransmits the received information.
In the system of this example, transmission / reception of the line quality measurement signal and the speed notification signal is performed at the time of starting the system and at regular intervals.
Further, in the system of this example, it is possible to adopt a configuration in which a radio channel different from the transmission of the information source is used for relay transmission.

  Various methods may be used as a method for determining a communication path and a transmission speed that can be most efficiently transmitted to all receiving counterpart stations based on the inter-station communication speed. For example, for information transmission A mode for determining a communication path and a transmission speed that require the shortest (and expected) time, or a communication path and a transmission speed that minimize the overall (expected) load on communication are determined. For example, a communication path that can use the fastest transmission rate and a mode for determining the transmission rate can be used, and various algorithms may be used.

Here, the configuration of the system and apparatus according to the present invention is not necessarily limited to the configuration described above, and various configurations may be used. The present invention can also be provided as, for example, a method or method for executing the processing according to the present invention, a program for realizing such a method or method, or a recording medium for recording the program. It is also possible to provide various systems and devices.
The application field of the present invention is not necessarily limited to the above-described fields, and the present invention can be applied to various fields.
In addition, as various processes performed in the system and apparatus according to the present invention, for example, the processor executes a control program stored in a ROM (Read Only Memory) in hardware resources including a processor and a memory. A controlled configuration may be used, and for example, each functional unit for executing the processing may be configured as an independent hardware circuit.
The present invention can also be understood as a computer-readable recording medium such as a floppy (registered trademark) disk or a CD (Compact Disc) -ROM storing the control program, and the program (itself). The processing according to the present invention can be performed by inputting the program from the recording medium to the computer and causing the processor to execute the program.

It is a figure which shows an example of arrangement | positioning of a radio station. It is a figure which shows the structural example of the communication apparatus which concerns on one Example of this invention. It is a figure which shows an example of the format of a transmission signal.

Explanation of symbols

  1 .... Transmission information memory 2 .... Communication control unit 3 .... Transmission unit 4 .... Transmission / reception switch (Transmission / reception SW) 5 .... Antenna 6 .... Reception unit 7 .... Line quality judgment unit 8.・ ・ Speed notification signal section, 9 ・ ・ Reception information memory, 10 ・ ・ Relay designation determination section, 11 ・ ・ Inter-station speed memory, 12 ・ ・ Speed / communication path determination section,

Claims (3)

In a wireless communication system configured with a plurality of wireless stations capable of changing the transmission rate, one wireless station transmits information to a plurality of other wireless stations simultaneously,
Each radio station transmits a channel quality measurement signal before starting transmission of information,
Means for receiving a signal for measuring line quality from another radio station;
Means for determining a transmission rate that can be used for transmission to and from each other radio station based on the received signal for channel quality measurement;
Means for transmitting to the other wireless station by a speed notification signal the speed at which transmission is possible between all other wireless stations based on the determination result;
Means for receiving a speed notification signal transmitted from another wireless station;
Means for storing a communication speed between stations based on the received speed notification signal;
Means for reading out the stored inter-station communication speed at the start of transmission of information and determining a communication path and transmission speed that can be transmitted to all receiving counterpart stations;
Means for adding information on the determined communication path to transmission information and transmitting at the determined transmission rate;
Means for receiving transmission information to which communication path information is added from another wireless station;
Means for retransmitting the received transmission information when the local station is designated as a relay station based on the received communication path information;
A wireless communication system comprising: The wireless communication system according to claim 1, wherein
Transmission / reception of the line quality measurement signal and the speed notification signal is performed at the start-up of the system and at regular intervals.
A wireless communication system. The wireless communication system according to claim 1 or 2,
The wireless channel used for transmission from the information source is different from the wireless channel used for relay transmission.
A wireless communication system.

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