JP5063255B2 - Transmission rate selection method and radio communication system - Google Patents

Description

  The present invention relates to a transmission rate selection method, a transceiver, and a communication system, and more particularly to a technique that is effective when applied to a wireless communication system that selects and transmits one transmission rate from a plurality of transmission rates.

In a wireless communication system, generally, a high reception power is required when performing a high-speed transmission, and only a low-speed transmission is performed when only a small reception power can be obtained. Also, the received power at the receiving side becomes smaller as the distance from the transmitting side becomes longer.
Therefore, in a wireless communication system in which one base station exists and the base station communicates with a terminal station existing within a certain range from the base station, communication can be performed only at a single transmission rate. In order to increase the distance between the base station and the terminal, it is necessary to decrease the transmission speed. When the transmission speed is increased, the distance between the base station and the terminal station decreases, and the transmission speed and the base There arises a problem that it is difficult to make the distance between the station and Ruizue compatible.
A multi-rate system that supports multiple transmission rates is a method for solving such a problem. For example, when the reception power is low due to a distance or the like, the transmission rate is reduced and the reception power is reduced. This is a system that enables communication even when it is small, and increases the transmission speed when reception power is large due to a short distance or the like, thereby enabling high-speed communication.
By using the multi-rate system in this way, it is possible to achieve both the area covered by the base station and high-speed transmission.
By the way, in the multi-rate system as described above, it is necessary to select an appropriate transmission rate according to the propagation environment between transmission and reception, and factors other than the reception power such as delay dispersion are factors that determine the optimum transmission rate. There are many things.
For example, in the following Non-Patent Document 1, the transmission transmission rate is determined from C / N0 (carrier power to noise power density ratio) and delay dispersion as received power.
In the following Non-Patent Document 2, the transmission rate is determined by the number of successful packet transmission successes and the number of failures.

A conventional transceiver configuration is shown in FIG.
The transmission data sequence is input to the transmission frame generation unit 10, subjected to various processes such as serial-parallel conversion and header / tailor addition as necessary, and output to the modulation unit 11. The transmission frame generation unit 10 can generate not only the transmission data series but also transmission frames for various controls.
The modulation unit 11 performs modulation at the transmission rate instructed by the transmission rate control unit 13 using the input frame, and outputs the result to the wireless transmission unit 12. The wireless transmission unit 12 transmits the input modulation signal.
In addition, when a radio signal is received by the radio reception unit 16, the received signal is output to the demodulation unit 15, and information related to the propagation path environment such as a received signal strength indicator (RSSI) is transmitted to the propagation path environment estimation unit 17. Output.
The demodulator 15 demodulates the input signal, outputs it to the received data generator 14 and information related to the propagation path environment obtained when demodulating (for example, delay dispersion, path metric in Viterbi algorithm, error vector), etc. Is input to the propagation path environment estimation unit 17.
The reception data generation unit 14 performs parallel-serial conversion, header / tailer removal, and the like on the input data to generate a reception data generation sequence.
The propagation path environment estimation unit 17 estimates the propagation path environment from various types of input information and outputs the estimated propagation path environment to the transmission rate control unit 13.
The transmission rate control unit 13 determines the transmission rate based on various types of input information and outputs the transmission rate to the modulation unit 11. As a specific speed determination method in the transmission speed control unit 13, for example, there is a method in which a table as shown in FIG.

As prior art documents related to the invention of the present application, there are the following.
Otsuki et al., "Transmission characteristics of modulation multi-level variable adaptive modulation method", IEICE (B-II), J78-B-II, PP.435-444, Jun. 1995. Nagata et al., "A Study on Dynamic Rate Switching Method in IEEE802.11 Wireless LAN," B-5-217, 2003 IEICE General Conference, March 2003

Since the wireless communication system does not require a wired connection between the transmission side and the reception side, there is no need to fix the device, and in particular, the Ruizue station is often movable freely.
Here, there is no problem when the moving speed is low, but if the moving speed is increased, transmission errors frequently occur and communication becomes impossible. This is because the propagation path environment rapidly changes due to movement and cannot follow the change. In general, the higher the transmission speed, the lower the moving speed at which the characteristics deteriorate.
Here, the method for obtaining the optimum transmission speed from C / N0 and delay dispersion described in the above-mentioned Non-Patent Document 1 does not take the movement speed into consideration, so that it is appropriate when the movement speed is high. A problem arises in that a transmission speed higher than the transmission speed is selected, resulting in frequent transmission errors.
In the method described in Non-Patent Document 2, the transmission speed is increased or decreased depending on whether the transmission is successful or unsuccessful. Similarly, a transmission speed higher than an appropriate transmission speed is selected for the moving speed. As a result, there arises a problem that transmission errors frequently occur.
The present invention has been made to solve the above-described problems of the prior art, and the object of the present invention is to take the moving speed into consideration when selecting the transmission speed, so that when the moving speed is high, It is an object of the present invention to provide a transmission rate selection method that makes it possible to select an appropriate transmission rate without selecting an inappropriate transmission rate.
Another object of the present invention is to provide a transceiver and a wireless communication system for executing the above transmission rate selection method.
The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.
(1) In a wireless communication system that performs wireless communication by selecting one transmission speed from a plurality of transmission speeds when performing transmission between a plurality of transceivers including at least one freely movable transceiver A transmission speed selection method for a transceiver, in which the maximum transmission speed is determined in advance according to the moving speed of the transceiver, the propagation path environment is estimated from the number of successful transmissions and the number of failures, and the transceiver is provided. From the time information based on the operating time of the moving body, the speed of the moving body corresponding to the time information is obtained, the obtained speed is detected as the moving speed of the own transceiver, and the transmission speed at the time of transmission is Based on the estimated propagation path environment and the detected moving speed, a transmission speed to be used for transmission is determined from the estimated propagation path environment when one transmission speed is selected from the plurality of transmission speeds. The determined transmission rate when the determined transmission rate is smaller than the maximum transmission rate according to the moving speed, or the determined transmission rate is the maximum transmission rate according to the moving speed. If equal or larger, the maximum transmission rate corresponding to the moving speed is selected as the one transmission rate.
(2) In a wireless communication system that performs wireless communication by selecting one transmission speed from a plurality of transmission speeds when transmitting between a plurality of transceivers including at least one freely movable transceiver A transmission speed selection method for a transceiver, in which the maximum transmission speed is determined in advance according to the moving speed of the transceiver, and the destination transceiver estimates the propagation path environment from the number of successful transmissions and the number of failures. The speed of the mobile body corresponding to the time information is obtained from time information based on the operation time of the mobile body equipped with the transmission / reception device of the transmission destination, and the obtained speed is detected as the movement speed of the own transceiver. The transmission / reception device notifies the estimated transmission path environment and the detected moving speed to the transmission / reception device, and the transmission / reception device transmits the transmission speed when performing transmission as follows: in front Based on the notified propagation path environment and the notified moving speed of the destination transceiver, when selecting one transmission speed from the plurality of transmission speeds, from the notified propagation path environment A transmission rate to be used for transmission is determined, and when the determined transmission rate is smaller than a maximum transmission rate according to a moving speed of the transmission / reception device of the transmission destination, the determined transmission rate or the determined If the transmission speed is equal to or greater than the maximum transmission speed corresponding to the moving speed, the maximum transmission speed corresponding to the moving speed is selected as the one transmission speed.

(3) In a wireless communication system that performs wireless communication by selecting one transmission speed from a plurality of transmission speeds when transmitting between a plurality of transceivers including at least one freely movable transceiver A transmission speed selection method for a transceiver, in which the maximum transmission speed is determined in advance according to the moving speed of the transceiver, and the destination transceiver estimates the propagation path environment from the number of successful transmissions and the number of failures. The speed of the mobile body corresponding to the time information is obtained from time information based on the operation time of the mobile body equipped with the transmission / reception device of the transmission destination, and the obtained speed is detected as the movement speed of the own transceiver. The transmission destination transceiver is based on the estimated propagation path environment and the detected moving speed, and the transmission speed at the time of transmission by the transmission source transceiver is one of the plurality of transmission speeds. When the transmission speed is selected, a transmission speed to be used for transmission is determined from the estimated propagation path environment. If the determined transmission speed is smaller than the maximum transmission speed corresponding to the moving speed, the transmission speed is determined. If the determined transmission rate is equal to or greater than the maximum transmission rate corresponding to the moving speed, the maximum transmission rate corresponding to the moving speed is selected as the one transmission rate. Then, the selected transmission rate is notified to the transmission / reception device of the transmission source.
(4) In any one of (1) to (3), when one transmission rate is selected from the plurality of transmission rates, the transmission rate is lowered by one step if the size of data to be transmitted is larger than a threshold value. select.

(5) A wireless communication system that performs wireless communication by selecting one transmission speed from a plurality of transmission speeds when transmitting between a plurality of transceivers including at least one freely movable transceiver. In this case, the maximum transmission speed is determined in advance according to the moving speed of the transceiver, and the plurality of transceivers are configured to estimate the propagation path environment from the number of successful transmissions / failures, and the transmission / reception A speed detection unit that obtains the speed of the mobile body corresponding to the time information from the time information based on the operation time of the mobile body equipped with the machine, and detects the obtained speed as the movement speed of the own transceiver; and transmission As the transmission speed when performing the transmission, one transmission speed is selected from the plurality of transmission speeds based on the propagation path environment estimated by the propagation path environment estimation section and the moving speed detected by the speed detection section. transmission The transmission rate control unit, when selecting one transmission rate from among the plurality of transmission rates, the transmission rate control unit uses transmission from the propagation path environment estimated by the propagation path environment estimation unit. A transmission speed is determined, and when the determined transmission speed is smaller than a maximum transmission speed corresponding to the moving speed detected by the speed detection unit, the determined transmission speed or the determined transmission speed is determined. Is equal to or greater than the maximum transmission speed corresponding to the moving speed, the maximum transmission speed corresponding to the moving speed is selected as the one transmission speed.
(6) A wireless communication system that performs wireless communication by selecting one transmission speed from a plurality of transmission speeds when transmitting between a plurality of transceivers including at least one freely movable transceiver. The maximum transmission speed is determined in advance according to the moving speed of the transmitter / receiver, and the transmission / reception destination transmitter / receiver transmits a propagation path environment estimation unit that estimates the propagation path environment from the number of successful transmissions / failures, and the transmission A speed detection unit that obtains the speed of the mobile body corresponding to the time information from the time information based on the operation time of the mobile body equipped with the previous transceiver and detects the obtained speed as the travel speed of the own transceiver And a propagation path environment / movement speed notification section for notifying the transmission / reception device of the propagation path environment estimated by the propagation path environment estimation section and the movement speed detected by the speed detection section, The original transceiver is A transmission rate control unit that selects one transmission rate from among the plurality of transmission rates based on the propagation path environment and the moving speed notified from the destination transceiver. When the transmission rate control unit of the transmission / reception device selects one transmission rate from the plurality of transmission rates, the transmission rate control unit performs transmission from the propagation path environment notified from the transmission / reception device. The transmission rate to be used is determined, and when the determined transmission rate is smaller than the maximum transmission rate according to the moving speed notified from the destination transceiver, the selected transmission rate is determined, or the determination When the transmitted transmission speed is equal to or greater than the maximum transmission speed corresponding to the moving speed, the maximum transmission speed corresponding to the moving speed is selected as the one transmission speed.

(7) A wireless communication system that performs wireless communication by selecting one transmission speed from a plurality of transmission speeds when transmitting between a plurality of transceivers including at least one freely movable transceiver. there are, in advance to determine the maximum transmission rate in accordance with the moving speed of advance transceiver, transmit destination transceiver, the channel environment estimation section that estimates a propagation path environment from the transmission success count, failure count, the Speed detection that obtains the speed of the mobile body corresponding to the time information from the time information based on the operating time of the mobile body equipped with the transmission / reception device and detects the obtained speed as the movement speed of the own transceiver And a plurality of transmission rates based on the propagation path environment estimated by the propagation path environment estimation unit and the moving speed detected by the speed detection unit One from A transmission rate control unit for selecting a transmission rate; and a transmission rate notification unit for notifying the transmission rate of the transmission rate selected by the transmission rate control unit to a transmission / reception device. A transmission rate control unit that selects, as the one transmission rate, the transmission rate notified from the transmission / reception device as the transmission rate, and the transmission rate control unit of the transmission / reception device includes: When one transmission rate is selected from the plurality of transmission rates, a transmission rate used for transmission is determined from the propagation path environment estimated by the propagation path environment estimation unit, and the determined transmission speed is used as the speed detection. If the transmission speed is smaller than the maximum transmission speed corresponding to the moving speed detected by the unit, the determined transmission speed is used, or if the determined transmission speed is equal to or greater than the maximum transmission speed corresponding to the moving speed. , The maximum transmission rate in accordance with the moving speed is selected as the one of the transmission rate.
(8) In any one of (5) to (7), when the transmission rate control unit selects one transmission rate from the plurality of transmission rates, the size of data to be transmitted is larger than a threshold value. For example, select a lower transmission rate.

According to the present invention, since the transmission speed is selected in consideration of not only the propagation path environment but also the moving speed as the transmission speed selection method for transmission, a high transmission speed can be used from the aspect of the propagation path environment. However, since the moving speed is high, it is possible to select an appropriate transmission speed even in an environment where transmission errors frequently occur at such a transmission speed.
Further, according to the present invention, the transmission rate selection method is selected individually by the method of selecting from the propagation path environment and the method of selecting from the moving speed, and the one having the lower transmission rate is selected. By such a method, the transmission rate can be controlled by the transmission rate while greatly reducing the correction points with respect to the conventional method.
In addition, according to the present invention, the propagation path state estimated from the received signal and the moving speed of the terminal are transmitted to the transmission / reception device, and the transmission / reception device estimates the propagation path speed. Frequency Division Duplex: A method in which the propagation path environment differs between reception and transmission, such as the frequency division method, or even in an environment where one terminal is moving but the other terminal is not moving Transmission speed control considering the speed becomes possible.
Further, according to the present invention, in order to determine the transmission rate to be transmitted next by the transmitter / receiver from the propagation path state estimated from the received signal and the moving speed of the own terminal, and to transmit the transmission rate to the transmitter / receiver For example, transmission speed control can be performed in consideration of the moving speed even in an environment such as FDD or in an environment where one terminal does not move.
Further, according to the present invention, when the transmission rate is selected according to the propagation path condition, the moving speed of the terminal itself, and the transmission frame length, the probability that a transmission error occurs with respect to the moving speed changes depending on the frame length. In addition, appropriate transmission rate control becomes possible.

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.
According to the present invention, by considering the moving speed when selecting the transmission speed, it is possible to select an appropriate transmission speed without selecting an inappropriate transmission speed when the moving speed is high. It becomes.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In all the drawings for explaining the embodiments, parts having the same functions are given the same reference numerals, and repeated explanation thereof is omitted.
[Example 1]
FIG. 1 is a block diagram illustrating a schematic configuration of a transceiver according to the first embodiment of the present invention.
The transmission data sequence is input to the transmission frame generation unit 10, subjected to various processes such as serial-parallel conversion and header / tailor addition as necessary, and output to the modulation unit 11. The transmission frame generation unit 10 can generate not only the transmission data series but also transmission frames for various controls.
The modulation unit 11 performs modulation at the transmission rate instructed by the transmission rate control unit 13 using the input frame, and outputs the result to the wireless transmission unit 12. The wireless transmission unit 12 transmits the input modulation signal.
Further, when the radio signal is received by the radio receiver 16, the received signal is output to the demodulator 15 and information related to the propagation path environment such as RSSl (Received Signal Strength Indicator) is sent to the propagation path environment estimation part 17. Output.
The demodulator 15 demodulates the input signal, outputs it to the received data generator 14 and information related to the propagation path environment obtained when demodulating (for example, delay dispersion, path metric in Viterbi algorithm, error vector), etc. Is input to the propagation path environment estimation unit 17.
The reception data generation unit 14 performs parallel-serial conversion, header / tailer removal, and the like on the input data to generate a reception data generation sequence. When a control frame is received, appropriate processing is performed.
The propagation path environment estimation unit 17 estimates the propagation path environment from various types of input information and outputs the estimated propagation path environment to the transmission rate control unit 13.
The speed detector 20 measures the moving speed of the terminal itself and outputs the information to the transmission speed controller 13.
The transmission rate control unit 13 determines the transmission rate based on various types of input information and outputs the transmission rate to the modulation unit 11.

One embodiment of the transmission rate selection method of the transmission rate controller 13 of this embodiment is shown in FIGS. FIG. 2 is a flowchart for explaining an example of the transmission rate determination process of the transmission rate control unit 13 of this embodiment, and FIG. 3 is a diagram showing the contents of the table used in the process shown in FIG. .
In FIG. 3, Ri (i = 1 to 4) indicates a transmission rate and has a relationship of R1 <R2 <R3 <R4. In FIG. 3, four types of speeds are used. However, the number of transmission speeds is not limited as long as two or more types are used.
In FIG. 2, first, the transmission rate control unit 13 acquires RSSI and moving speed (step 101).
Next, the transmission rate is acquired from the acquired information from the table shown in FIG. 3 (step 102).
Another form of the transmission rate selection method of the transmission rate control unit 13 of the present embodiment is shown in FIGS.

FIG. 4 is a flowchart for explaining another example of the transmission rate determination process of the transmission rate control unit 13 of this embodiment, and FIG. 5 is a diagram showing the contents of the table used in the process shown in FIG. It is.
First, the maximum transmission speed Rv is determined from the moving speed V according to the table shown in FIG. 5 (step 111). Here, Rvi is selected as Rv for the minimum i that satisfies Vi> V (movement speed).
Next, the transmission rate control unit 13 determines the transmission rate R from the propagation path environment or the like by an existing transmission rate control method (step 112).
Next, Rv and R are compared (step 113). If R ≧ Rv, Rv is selected as the transmission rate used for transmission (step 115). If R <Rv, transmission used for transmission is selected. R is selected as the speed (step 114).

FIG. 6 is a diagram showing a state of transmission / reception in the present embodiment.
In FIG. 6, when the transceiver B receives data from the transceiver A (step 121 in FIG. 6), the propagation path environment estimation unit 17 estimates the propagation path environment from various input information, and The speed detector 20 measures the moving speed of the terminal itself.
Then, the transmission rate control unit 13 determines the transmission rate when the terminal itself transmits (step 122 in FIG. 6) according to the flow shown in FIG. 2 or FIG.
In the above description, the transmission speed is determined from the propagation path environment and the moving speed. However, the transmission speed can also be used in a method for determining the transmission speed based on the number of successful transmissions and the number of failures. For example, a method is conceivable in which a maximum transmission speed is determined in advance according to the moving speed, and a predetermined transmission speed is used when the transmission speed is equal to or higher than the transmission speed determined by the number of transmission successes / failures.
The present embodiment is used when the channel environment of the channel used for reception and the channel environment of the channel used for transmission have a large correlation as in TDD (Time Division Duplex).

[Example 2]
FIG. 7 is a block diagram illustrating a schematic configuration of the transceiver according to the second embodiment of the present invention.
The transmission data sequence is input to the transmission frame generation unit 10, subjected to various processes such as serial-parallel conversion and header / tailor addition as necessary, and output to the modulation unit 11. At this time, all or part of the data input from the propagation path environment estimation unit 17, the transmission rate control unit 13, the reception data generation unit 14, and the radio reception unit 16 is stored in the header / tailer. The transmission frame generation unit 10 can generate not only the transmission data series but also transmission frames for various controls.
The modulation unit 11 performs modulation at the transmission rate instructed by the transmission rate control unit 13 using the input frame, and outputs the result to the wireless transmission unit 12. The wireless transmission unit 12 transmits the input modulation signal. The transmission frame generation unit 10, the modulation unit 11, and the radio transmission unit 12 constitute a propagation path environment / movement speed notification unit of the present invention.
In addition, when a radio signal is received by the radio reception unit 16, the received signal is output to the demodulation unit 15, and information related to the propagation path environment such as a received signal strength indicator (RSSI) is transmitted to the propagation path environment estimation unit 17. Output.
The demodulator 15 demodulates the input signal, outputs it to the received data generator 14 and information related to the propagation path environment obtained when demodulating (for example, delay dispersion, path metric in Viterbi algorithm, error vector), etc. Is input to the propagation path environment estimation unit 17.

The reception data generation unit 14 performs parallel-serial conversion, header / tailer removal, and the like on the input data to generate a reception data generation sequence. At the same time, if the propagation path environment information, the transmission speed of the transmission source, the transmission rate estimated by the transmission source, and the like are included in the header / tailer, they are extracted and output to the transmission rate control unit 13. When a control frame is received, appropriate processing is performed.
The propagation path environment estimation unit 17 estimates the propagation path environment from various types of input information, and outputs it to the transmission rate control unit 13 and the transmission frame generation unit 10.
The speed detector 20 measures the speed of its own terminal and outputs the information to the transmission speed controller 13 and the transmission frame generator 10.
The transmission rate control unit 13 determines a transmission rate to be used when the transmission unit 13 transmits the information based on various input information and outputs the transmission rate to the modulation unit 11.
At the same time, the opposite station (base station or terminal station) can determine the transmission rate to be used when transmitting to the own station, and can determine the transmission rate and output it to the transmission frame generator 10. The specific method for determining the transmission rate is the same as in the first embodiment.

FIG. 8 is a diagram illustrating an example of transmission / reception in the present embodiment.
In FIG. 8, when the transceiver B receives data from the transceiver A (step 131 in FIG. 8), the propagation path environment estimation unit 17 estimates the propagation path environment from various input information, and The speed detector 20 measures the moving speed of the terminal itself.
Thereafter, the transceiver B transmits to the transceiver A the estimated propagation path environment and the moving speed of the transceiver included in the transmission signal (step 132 in FIG. 8). The transmission rate at step 132 is selected according to the flow shown in FIG. 2 or FIG. 4 described above or by a conventional method.
The transceiver A extracts the propagation path environment and the moving speed from the received signal, and the transmission speed control unit 13 uses the transmission speed used for the next transmission according to the flow shown in FIG. 2 or FIG. Is determined (step 133 in FIG. 8).
Although FIG. 8 shows a method for determining the transmission rate in the transmitter / receiver A, the method for determining the transmission rate in the transmitter / receiver B is also possible with the same means.

FIG. 9 is a diagram illustrating another example of the state of transmission / reception in the present embodiment.
In FIG. 9, when the transceiver B receives data from the transceiver A (step 141 in FIG. 9), the propagation path environment estimation unit 17 estimates the propagation path environment from various input information, and The speed detector 20 measures the moving speed of the terminal itself. Then, the transmission rate control unit 13 determines the transmission rate used by the transceiver A.
Thereafter, the transmitter / receiver B transmits the determined transmission speed to the transmitter / receiver A by including it in the header / tailer when transmitting the data alone or other data (step 142 in FIG. 8). The transmission rate in step 142 is selected according to the flow shown in FIG. 2 or FIG. 4 described above or by a conventional method.
The transceiver A extracts the transmission rate to be used from the received signal and uses it as the transmission rate when the transmitter / receiver A next transmits to the transceiver B (step 143 in FIG. 9).
In this case, when the transmitter / receiver A does not move like the fixed base station, a configuration in which the speed detector 20 is omitted as shown in FIG. 10 may be considered.
The present embodiment is used when the channel environment of the channel used for reception and the channel used for transmission is small, such as FDD (Frequency Division Duplex).
Further, in combination with the first embodiment, the present embodiment is used to determine the transmission rate in the downlink direction (base station to terminal station), and the above-described transmission rate determination in the uplink direction (from the terminal station to base station). There is a method using the first embodiment.

[Example 3]
FIG. 11 is a block diagram illustrating a schematic configuration of the transceiver according to the third embodiment of the present invention.
The transmission data sequence is input to the transmission frame generation unit 10, subjected to various processes such as serial-parallel conversion and header / tailer addition as necessary, and output to the modulation unit 11. The transmission frame generation unit 10 can generate not only the transmission data series but also transmission frames for various controls. The length of the simultaneously generated frame is output to the transmission rate control unit 13.
The modulation unit 11 performs modulation at the transmission rate instructed by the transmission rate control unit 13 using the input frame, and outputs the result to the wireless transmission unit 12. The wireless transmission unit 12 transmits the input modulation signal.
In addition, when a radio signal is received by the radio reception unit 16, the received signal is output to the demodulation unit 15, and information related to the propagation path environment such as a received signal strength indicator (RSSI) is transmitted to the propagation path environment estimation unit 17. Output.
The demodulator 15 demodulates the input signal, outputs it to the received data generator 14 and information related to the propagation path environment obtained when demodulating (for example, delay dispersion, path metric in Viterbi algorithm, error vector), etc. Is input to the propagation path environment estimation unit 17.
The reception data generation unit 14 performs parallel-serial conversion, header / tailer removal, and the like on the input data to generate a reception data generation sequence.
The propagation path environment estimation unit 17 estimates the propagation path environment from various types of input information and outputs the estimated propagation path environment to the transmission rate control unit 13.
The speed detector 20 measures the moving speed of the terminal itself and outputs the information to the transmission speed control.
The transmission rate control unit 13 determines the transmission rate based on various types of input information and outputs the transmission rate to the modulation unit 11.
In the transmission rate determination method of the transmission rate control unit 13, in addition to the determination method of the first embodiment described above, the length of a frame to be transmitted is also used as a determination criterion. For example, if the length of the frame to be transmitted is larger than a certain threshold, it can be considered that the one-stage speed is lower than the transmission speed determined by the transmission speed determination method in the first embodiment. .
Further, FIG. 11 is described based on the above-described first embodiment, but a similar method can be considered in the above-described second embodiment.

In the description of each of the embodiments described above, a method for realizing a variable transmission rate is not mentioned, but not only a normal modulation method such as BPSK, QPSK, 16QAM, 64QAM, and 256QAM, The same applies to the number of antennas in MIMO (Multiple Input Multiple Output) and combinations thereof.
In the description of each embodiment described above, as a speed detection method, a method of directly reading from a speedometer, a method of estimating speed from a position detection function such as GPS (Global Positioning System), or a train in advance. If the operation time is long and there is no sudden speed change, time information and a speed corresponding to each time are stored in advance, and a method of reading out from there is considered.
As mentioned above, the invention made by the present inventor has been specifically described based on the above embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Of course.

It is a block diagram which shows schematic structure of the transmitter / receiver of Example 1 of this invention. It is a flowchart for demonstrating an example of the transmission rate determination process of the transmission rate control part of Example 1 of this invention. It is a figure which shows the content of the table used in the process shown in FIG. It is a flowchart for demonstrating the other example of the transmission rate determination process of the transmission rate control part of Example 1 of this invention. It is a figure which shows the content of the table used in the process shown in FIG. It is a figure which shows the mode of transmission / reception in Example 1 of this invention. It is a block diagram which shows schematic structure of the transmitter / receiver of Example 2 of this invention. It is a figure which shows an example of the mode of the transmission / reception in Example 2 of this invention. It is a figure which shows the other example of the mode of transmission / reception in Example 2 of this invention. It is a block diagram which shows schematic structure of the modification of the transmitter / receiver of Example 2 of this invention. It is a block diagram which shows schematic structure of the transmitter / receiver of Example 3 of this invention. It is a block diagram which shows schematic structure of the conventional transmitter / receiver. It is a figure which shows the content of the table used for the speed determination method of the transmission rate control part shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Transmission frame production | generation part 11 Modulation part 12 Wireless transmission part 13 Transmission rate control part 14 Reception data generation part 15 Demodulation part 16 Wireless reception part 17 Channel environment estimation part 20 Speed detection part

Claims (8)

Of a transceiver in a wireless communication system that performs wireless communication by selecting one transmission speed from a plurality of transmission speeds when transmitting between a plurality of transceivers including at least one freely movable transceiver A transmission speed selection method,
The maximum transmission speed is determined in advance according to the moving speed of the transceiver,
Estimate the propagation path environment from the number of successful transmissions / failures,
From the time information based on the operating time of the mobile body equipped with the transceiver, find the speed of the mobile body corresponding to the time information, detect the determined speed as the traveling speed of the own transceiver,
Based on the estimated propagation path environment and the detected moving speed, a transmission speed for transmission is determined based on the estimated propagation path environment when selecting one transmission speed from the plurality of transmission speeds. A transmission rate to be used for transmission is determined, and when the determined transmission rate is smaller than a maximum transmission rate according to the moving speed, the determined transmission rate is used, or the determined transmission rate is the moving rate. A transmission rate selection method comprising: selecting a maximum transmission rate according to the moving speed as the one transmission rate when the transmission rate is equal to or greater than a maximum transmission rate according to a rate. Of a transceiver in a wireless communication system that performs wireless communication by selecting one transmission speed from a plurality of transmission speeds when transmitting between a plurality of transceivers including at least one freely movable transceiver A transmission speed selection method,
The maximum transmission speed is determined in advance according to the moving speed of the transceiver,
The transmission / reception device of the transmission destination estimates the propagation path environment from the number of successful transmissions / failures, and corresponds to the time information from the time information based on the operating time of the mobile body equipped with the transmission / reception device of the transmission destination. obtain a speed of the movable body, and detects the speed obtained the as the moving speed of its own transceiver,
The transmission / reception device notifies the transmission / reception device of the estimated propagation path environment and the detected moving speed,
Based on the notified propagation path environment and the notified moving speed of the transmission / reception device, the transmission / reception device of the transmission source is selected from the plurality of transmission rates. When selecting one transmission rate, the transmission rate used for transmission is determined from the notified propagation path environment, and the determined transmission rate is greater than the maximum transmission rate according to the moving speed of the destination transceiver. Is less than the determined transmission rate, or the determined transmission rate is equal to or greater than the maximum transmission rate according to the moving speed, the maximum transmission rate according to the moving speed. , And selecting the transmission rate as one transmission rate. Of a transceiver in a wireless communication system that performs wireless communication by selecting one transmission speed from a plurality of transmission speeds when transmitting between a plurality of transceivers including at least one freely movable transceiver A transmission speed selection method,
The maximum transmission speed is determined in advance according to the moving speed of the transceiver,
The transmission / reception device of the transmission destination estimates the propagation path environment from the number of successful transmissions / failures, and corresponds to the time information from the time information based on the operating time of the mobile body equipped with the transmission / reception device of the transmission destination. obtain a speed of the movable body, and detects the speed obtained the as the moving speed of its own transceiver,
Based on the estimated propagation path environment and the detected moving speed, the transmission destination transmitter / receiver transmits one transmission rate from among the plurality of transmission rates as a transmission rate when the transmission source transmitter / receiver performs transmission. When selecting a speed, a transmission speed to be used for transmission is determined from the estimated propagation path environment, and if the determined transmission speed is smaller than a maximum transmission speed corresponding to the moving speed, the determined transmission is performed. A speed, or if the determined transmission speed is equal to or greater than a maximum transmission speed according to the movement speed, select a maximum transmission speed according to the movement speed as the one transmission speed;
The transmission rate selection method, wherein the selected transmission rate is notified to the transmitter / receiver.   4. When selecting one transmission rate from among the plurality of transmission rates, a transmission rate that is one step lower is selected if the size of data to be transmitted is larger than a threshold value. The transmission rate selection method according to any one of the above. A wireless communication system that performs wireless communication by selecting one transmission speed from a plurality of transmission speeds when transmitting between a plurality of transceivers including at least one freely movable transceiver,
The maximum transmission speed is determined in advance according to the moving speed of the transceiver,
The plurality of transceivers, a propagation path environment estimation unit that estimates a propagation path environment from the number of transmission successes and the number of failures,
A speed detector that obtains the speed of the mobile body corresponding to the time information from the time information based on the operating time of the mobile body equipped with the transceiver and detects the obtained speed as the moving speed of the own transceiver When,
As a transmission rate for transmission, one transmission rate is selected from the plurality of transmission rates based on the propagation path environment estimated by the propagation path environment estimation unit and the moving speed detected by the speed detection unit. A transmission rate control unit
The transmission rate control unit determines a transmission rate to be used for transmission from the propagation path environment estimated by the propagation path environment estimation unit when selecting one transmission rate from the plurality of transmission rates. If the transmission speed is smaller than the maximum transmission speed corresponding to the moving speed detected by the speed detector, the determined transmission speed is set, or the determined transmission speed is the maximum corresponding to the moving speed. When the transmission speed is equal to or greater than the transmission speed, a maximum transmission speed corresponding to the moving speed is selected as the one transmission speed. A wireless communication system that performs wireless communication by selecting one transmission speed from a plurality of transmission speeds when transmitting between a plurality of transceivers including at least one freely movable transceiver,
The maximum transmission speed is determined in advance according to the moving speed of the transceiver,
The transmission / reception device of the transmission destination is a propagation path environment estimation unit that estimates the propagation path environment from the number of transmission successes / failures,
A speed at which the speed of the mobile body corresponding to the time information is obtained from time information based on the operation time of the mobile body equipped with the transmission / reception device of the transmission destination and the obtained speed is detected as the movement speed of the own transceiver A detection unit;
A propagation path environment / movement speed notification section for notifying the transmission path environment estimated by the propagation path environment estimation section and the moving speed detected by the speed detection section to a transmission / reception device;
The transmission / reception device of the transmission source sets one transmission rate from among the plurality of transmission rates based on the propagation path environment and the movement speed notified from the transmission / reception device of the transmission destination as a transmission rate at the time of transmission. A transmission rate control unit to select,
The transmission rate control unit of the transmission / reception device, when selecting one transmission rate from the plurality of transmission rates, transmits the transmission from the propagation path environment notified from the transmission / reception device. And determining the selected transmission rate when the determined transmission rate is smaller than the maximum transmission rate corresponding to the moving speed notified from the transmission / reception device of the transmission destination, or the determined transmission rate. A wireless communication system, wherein when a transmission rate is equal to or greater than a maximum transmission rate corresponding to the moving speed, a maximum transmission rate corresponding to the moving speed is selected as the one transmission rate. A wireless communication system that performs wireless communication by selecting one transmission speed from a plurality of transmission speeds when transmitting between a plurality of transceivers including at least one freely movable transceiver,
The maximum transmission speed is determined in advance according to the moving speed of the transceiver,
Send destination transceiver, the channel environment estimation section that estimates a propagation path environment from the transmission success count, failure count,
A speed at which the speed of the mobile body corresponding to the time information is obtained from time information based on the operation time of the mobile body equipped with the transmission / reception device of the transmission destination and the obtained speed is detected as the movement speed of the own transceiver A detection unit;
Based on the propagation path environment estimated by the propagation path environment estimation unit and the movement speed detected by the speed detection unit, the transmission speed at the time when the transmission / reception device of the transmission source performs transmission is selected from the plurality of transmission speeds. A transmission rate control unit for selecting one transmission rate;
A transmission rate notification unit for notifying the transmission rate of the transmission rate selected by the transmission rate control unit to a transmission / reception device;
The transmission / reception device includes a transmission rate control unit that selects, as the one transmission rate, a transmission rate notified from the transmission / reception device as a transmission rate for transmission.
The transmission speed control unit of the transmission / reception device of the transmission destination uses a transmission speed used for transmission from the propagation path environment estimated by the propagation path environment estimation part when selecting one transmission speed from the plurality of transmission speeds. When the determined transmission rate is smaller than the maximum transmission rate corresponding to the moving speed detected by the speed detection unit, the determined transmission rate, or the determined transmission rate is the A wireless communication system, wherein a maximum transmission rate corresponding to the moving speed is selected as the one transmission rate when equal to or greater than a maximum transmission rate corresponding to a moving speed.   The transmission rate control unit, when selecting one transmission rate from the plurality of transmission rates, selects a transmission rate that is one step lower if the size of data to be transmitted is larger than a threshold value. The wireless communication system according to any one of claims 5 to 7.

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