JP3410466B1 - System and method for packet transmission - Google Patents

Abstract

Abstract: [PROBLEMS] To reduce the number of data retransmissions between transmission and reception,
Improve transmission efficiency. When a signal requesting new data transmission is input, a transmission signal switching unit outputs an output signal of an error correction coding unit to a modulation unit and receives a signal requesting data retransmission. , And outputs the signal stored in the buffer 103 to the modulation unit 106. When a signal requesting new data transmission is input, modulation scheme determining section 105 controls modulation section 106 so as to perform modulation using the maximum rate modulation scheme. On the other hand, when a signal requesting data retransmission is input, modulation scheme determination section 105 controls modulation section 106 to perform modulation using the modulation scheme for retransmission. As a method of determining a modulation scheme for retransmission, a method of setting a rate obtained by multiplying a maximum rate by a predetermined constant (for example, 0.5) or a method of determining a BPS
A method of fixing to a phase modulation method such as K or QPSK may be used.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a data transmission system and a packet transmission method used for packet transmission communication.

[0002]

2. Description of the Related Art Conventionally, in packet communication, a packet in which an error is detected is retransmitted (ARQ: Auto
A certain quality is guaranteed by a matic repeat request). Hereinafter, the exchange of signals between the devices of the conventional packet transmission system using ARQ will be briefly described.
In the following description, a device that transmits ARQ target data is referred to as a transmission side device, and a device that receives ARQ target data is referred to as a reception side device.

First, the transmission side device transmits data to the reception side device at the maximum rate that can be used at that time, and the reception side device performs error detection processing on the received data.

When an error is detected, the receiving side device transmits a signal for requesting retransmission of data to the transmitting side device (hereinafter referred to as "NACK signal"). on the other hand,
If no error is detected, the reception side device requests the transmission side device to transmit the next data (hereinafter referred to as “AC
K signal ”).

When the transmitting side device receives the NACK signal, it retransmits the same data as the previous time to the receiving side device at the maximum rate that can be used at that time. On the other hand, the transmitting device is
When the CK signal is received, the next data is transmitted to the receiving side device at the maximum rate that can be used at that time.

As described above, in the conventional packet transmission system, when the receiving side device detects an error in the received data, a retransmission request is made, and when the transmitting side device receives the retransmission request, the same data is retransmitted. .

[0007]

However, in the conventional packet transmission system, since the transmitting side device selects the transmission method at the time of retransmission on the same basis as that at the time of new transmission, the situation at the time of retransmission is also poor. However, there is a problem in that an error occurs again in the case of the above line, and as a result, the number of retransmissions increases and the transmission efficiency deteriorates. In particular, in multi-level modulation such as 16QAM, deterioration is severe in the presence of multipaths, and even if the transmission power is increased, the likelihood of each bit cannot be effectively increased. Usually, the switching of the transmission method cannot be performed so fast as to follow the fading, so that such a phenomenon may occur frequently.

The present invention has been made in view of the above circumstances, and provides a packet transmission system and a packet transmission method capable of reducing the number of times of data retransmission between transmission and reception and improving the transmission efficiency. With the goal.

[0009]

The transmitting side device of the present invention is
Transmission used in packet transmission system using ARQ
Device, which is a new device according to the request from the receiving device.
Data selection means for selecting data or resend data,
When sending new data or resending data,
Set the transmission rate based on the reception quality at the receiving device.
Select by the rate setting means to be set and the data selecting means
The transmitted data set by the rate setting means
A rate setting means for modulating the rate, and the rate setting
The means determines the transmission rate when data is retransmitted.
The data transmission rate is set independently of the transmission rate for new transmission of data .

The transmitting side apparatus of the present invention is a device using ARQ.
A transmitting device used in a packet transmission system,
New data or resend according to the request from the receiving device
Data selecting means for selecting data and the receiving side device
Rate to set the transmission rate based on the reception quality in
The data selected by the setting means and the data selecting means
Modulates the transmission rate set by the rate setting means
And a modulation means for
When transmitting data, the desired quality is obtained at the receiving device.
Set the maximum rate that can be
Obtain the desired quality at the receiving device when retransmitting data
It is configured to set a rate lower than the maximum possible rate .

Rate setting procedure in the transmitting side apparatus of the present invention
When the data is retransmitted,
The rate calculated by multiplying the maximum rate obtained by a predetermined constant
Take the configuration to set .

With these configurations, it is possible to employ a transmission method having a good error rate characteristic by using a standard different from that at the time of new transmission at the time of retransmission, so that it is possible to reduce the number of times of data retransmission between transmission and reception. It is possible to improve efficiency.

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

The base station apparatus according to the present invention is capable of transmitting any one of the above.
A configuration including a receiving side device is adopted. Further, the communication terminal device of the present invention has a configuration including any one of the above-mentioned transmission side devices .

With these configurations, the number of times data is retransmitted between transmission and reception can be reduced, so that transmission efficiency can be improved.

The packet transmission method of the present invention uses ARQ.
Of the transmitting device used in the existing packet transmission system.
Packet transmission method according to the request from the receiving device.
Select new data or resend data by selecting data
Process and transmission quality based on the reception quality at the receiving side device.
Rate setting step for setting the signal rate and the data selection
Set the data selected in the process in the rate setting process.
A modulation step of modulating to a fixed transmission rate,
The rate setting step is performed by the receiving device when transmitting new data.
Set the maximum rate at which the desired quality can be obtained.
When the data is retransmitted, the receiving side device
Than the maximum rate at which you can get the desired quality in
Set a lower rate .

According to this method, it is possible to employ a transmission method having a good error rate characteristic by using a criterion different from that at the time of new transmission at the time of retransmission, so that the number of times of data retransmission between transmission and reception can be reduced and transmission efficiency can be reduced. Can be improved.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION The essence of the present invention is to select a transmission scheme having a good error rate characteristic at the time of retransmission by using a criterion different from that at the time of new transmission.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each of the following embodiments, a case of controlling a modulation method which is one of transmission methods will be described.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of a packet transmission system according to Embodiment 1 of the present invention. The packet transmission system shown in FIG. 1 includes a transmitter device 100 and a receiver device 150.

The transmission side apparatus 100 includes an error detection bit adding section 101, an error correction coding section 102, and a buffer 10.
3, the transmission signal switching unit 104, and the modulation method determination unit 10
5, a modulation unit 106, a transmission radio unit 107, an antenna 108, an antenna sharing unit 109, and a reception radio unit 110.
A demodulation unit 111 and a separation unit 112.

The error detection bit addition section 101 adds error detection bits to the transmission data to be ARQ. The error correction coding unit 102 performs error correction coding processing on the output signal of the error detection bit addition unit 101. Buffer 1
03 temporarily stores the output signal of the error correction coding unit 102.

The transmission signal switching unit 104 includes a separation unit 112.
Signal requesting the transmission of the next data (hereinafter referred to as "ACK
Signal ”) is input, the error correction coding unit 1
The signal encoded in 02 is output to the modulator 106.
On the other hand, the transmission signal switching unit 104 outputs the signal accumulated in the buffer 103 to the modulation unit 106 when a signal requesting data retransmission (hereinafter referred to as “NACK signal”) is input from the separation unit 112. .

Modulation method determination section 105 determines the modulation method based on the ACK signal / NACK signal input from demultiplexing section 112 and a signal indicating the quality of the received signal (hereinafter referred to as "reception quality signal"), and the modulation section Control 106. The details of the method of determining the modulation method in the modulation method determination unit 105 will be described later.

Modulation section 106 modulates the output signal of transmission signal switching section 104 by a modulation method under the control of modulation method determination section 105. The transmission radio unit 107 includes a modulation unit 106.
Then, a predetermined wireless process such as up-conversion is performed on the output signal of.

The antenna sharing unit 109 is used for the transmission radio unit 10.
The output signal of No. 7 is wirelessly transmitted from the antenna 108, and the signal received by the antenna 108 is output to the reception wireless unit 110.

The reception radio unit 110 is the antenna sharing unit 10.
Predetermined wireless processing such as down conversion is performed on the output signal of 9. The demodulation unit 111 demodulates the output signal of the reception wireless unit 110.

Separation section 112 separates the output signal of demodulation section 111 into three parts, that is, reception data, ACK signal / NACK signal, and reception quality signal, and outputs the reception data to a reception processing circuit in a subsequent stage (not shown), and ACK. The signal or NACK signal is output to transmission signal switching section 104 and modulation scheme determination section 105, and the reception quality signal is output to modulation scheme determination section 105.

The receiving side device 150 has an antenna 151,
Antenna sharing section 152, reception radio section 153, demodulation section 154, error correction decoding section 155, and error detection section 156.
A reception quality measuring unit 157 and a transmission frame creating unit 15
8, a modulator 159, and a transmission radio unit 160.

The antenna sharing unit 152 is used by the transmission radio unit 16
The output signal of 0 is wirelessly transmitted from the antenna 151, and the signal received by the antenna 151 is output to the reception wireless unit 153.

The reception radio section 153 is the antenna sharing section 15
A predetermined wireless process such as down conversion is applied to the two output signals. The demodulation unit 154 demodulates the output signal of the reception wireless unit 153. The error correction decoding unit 155 includes the demodulation unit 15
The decoding process for error correction is performed on the demodulated data output from No. 4.

The error detection unit 156 is provided in the error correction decoding unit 15
Error detection is performed on the decoded data output from S5.
Then, the error detecting unit 156 outputs an ACK signal to the transmission frame creating unit 158 when no error is detected,
When an error is detected, the transmission frame creation unit 158 is NA
Output CK signal.

The reception quality measuring section 157 obtains the quality of the reception signal by measuring the SIR (reception signal to interference power ratio) or the reception electric field strength, and the reception quality signal indicating the quality of the reception signal is transmitted frame creating section 158. Output to.

The transmission frame creating section 158 performs framing for multiplexing the ACK signal / NACK signal and the reception quality signal on the transmission data, and outputs the transmission frame signal which is a framed signal to the modulating section 159.

The modulator 159 modulates the transmission frame signal. The transmission radio section 160 performs predetermined radio processing such as up-conversion on the output signal of the modulation section 159.

Next, the transmitting side device 100 and the receiving side device 15
The flow of the data transmission process performed with 0 will be described.
First, the error detection bit addition unit 101 of the transmission side apparatus 100
Then, an error detection bit is added to the ARQ target transmission data, and the error correction coding unit 102 performs error correction coding processing. The transmission signal that has been subjected to error correction coding processing is stored in the buffer 1
In addition to being stored in 03, it is output to the modulation section 106 via the transmission signal switching section 104.

In the modulation unit 106, the transmission signal is modulated by the modulation system of the maximum rate at the time under the control of the modulation system determination unit 105, and the modulated transmission signal is transmitted by the transmission radio unit 107.
Then, predetermined wireless processing is performed, and wireless transmission is performed from the antenna 108 via the antenna sharing unit 109.

The signal wirelessly transmitted from the transmitting side apparatus 100 is received by the antenna 151 of the receiving side apparatus 150, and is output to the reception radio section 153 via the antenna sharing section 152. The reception radio section 153 performs predetermined radio processing on the radio frequency reception signal, and outputs the baseband reception signal to the reception quality measuring section 157 and the demodulation section 154. The reception quality measuring unit 157 obtains the quality of the received signal, and the reception quality signal of this received signal is output to the transmission frame creation unit 158.

Further, the demodulation section 154 demodulates the received signal. The demodulated data is subjected to error correction decoding processing by the error correction decoding unit 155, and error detection is performed by the error detection unit 156. Here, if an error is detected, the error detection unit 156 outputs a NACK signal to the transmission frame creation unit 158.

The transmission frame creation section 158 performs framing for multiplexing the reception quality signal and the NACK signal on the transmission data, and outputs the transmission frame signal to the modulation section 159.

The transmission frame signal is modulated by modulation section 159, subjected to predetermined radio processing by transmission radio section 160, and then transmitted wirelessly from antenna 151 via antenna sharing section 152.

The signal wirelessly transmitted from the reception side device 150 is received by the antenna 108 of the transmission side device 100, and is output to the reception radio section 110 via the antenna sharing section 109. Predetermined wireless processing is performed by the reception wireless unit 110, demodulated by the demodulation unit 111, and output to the separation unit 112.

The demultiplexing unit 112 demultiplexes the demodulated signal into received data, a NACK signal and a received quality signal,
Received data is output to the reception processing circuit in the subsequent stage (not shown),
The NACK signal is output to transmission signal switching section 104 and modulation scheme determination section 105, and the reception quality signal is output to modulation scheme determination section 105.

When the transmission signal switching unit 104 recognizes the retransmission request from the NACK signal, the signal accumulated in the buffer 103 (hereinafter referred to as “retransmission signal”) is output to the modulation unit 106 via the transmission signal switching unit 104. To be done.

When the modulation scheme decision section 105 recognizes the retransmission request from the NACK signal, the modulation scheme for retransmission is decided. In the modulation unit 106, the retransmission signal is modulated by the modulation scheme for retransmission under the control of the modulation method determination unit 105, the modulated retransmission signal is subjected to predetermined wireless processing in the transmission wireless unit 107, and is passed through the antenna sharing unit 109. Antenna 10
Wirelessly transmitted from 8.

The retransmitted signal wirelessly transmitted from the transmitting side apparatus 100 is received by the antenna 151 of the receiving side apparatus 150, and is output to the reception radio section 153 via the antenna sharing section 152. In the reception radio unit 153, a predetermined radio processing is performed on the reception retransmission signal of the radio frequency, and the reception retransmission signal of the base band is received by the reception quality measuring unit 157 and the demodulation unit 1.
It is output to 54.

Reception quality measuring section 157 obtains the quality of the received retransmission signal, and the reception quality signal of this received retransmission signal is output to transmission frame creation section 158. Demodulation unit 154
Then, the received retransmission signal is demodulated.

The demodulated retransmission data is sent to the error correction decoding unit 155.
Then, a decoding process for error correction is performed, and the error detection unit 156 performs error detection. Here, if no error is detected, the transmission frame creation unit 1
An ACK signal is output to 58, and the received demodulated data is output to a reception processing circuit in the subsequent stage (not shown).

In the transmission frame creating section 158, the ACK signal and the reception quality signal are multiplexed into transmission data into frames, which are wirelessly transmitted from the antenna 151 via the modulating section 159, the transmission radio section 160 and the antenna sharing section 152. It

The signal received by the antenna 108 of the transmitting side apparatus 100 is transmitted to the antenna sharing section 109 and the reception radio section 11
0, output to the separation unit 112 via the demodulation unit 111, the separated ACK signal is output to the transmission signal switching unit 104 and the modulation scheme determination unit 105, and the separated reception quality signal is output to the modulation scheme determination unit 105. To be done.

After that, by the switching control of the transmission signal switching unit 104, the error correction coding unit 102 outputs a new transmission signal to the modulation unit 106, and the buffer 103 stores the new transmission signal.

In the modulation section 106, the modulation method determination section 105
The transmission signal is modulated by the modulation method of the maximum rate at that time by the control of, and the modulated transmission signal is transmitted by the transmission radio unit 10
A predetermined wireless process is performed at 7, and the signal is wirelessly transmitted from the antenna 108 via the antenna sharing unit 109.

As described above, in the packet transmission system according to the first embodiment of the present invention, the modulation method is made different between new transmission and retransmission.

Next, the details of the method of determining the modulation method in the modulation method determination unit 105 will be described. First, the modulation scheme determination unit 105 obtains the maximum rate modulation scheme that can obtain a predetermined reception quality based on the reception quality signal. For example, if the reception quality is good, 16QAM or 6
A high-rate modulation method such as 4QAM is used, and a low-rate modulation method such as QPSK is used when the reception quality is poor.

Then, the modulation scheme determination unit 105 sends an ACK
When a signal is input, the modulation unit 106 is controlled so as to perform modulation with the obtained maximum rate modulation method. On the other hand, when the NACK signal is input, the modulation scheme determination unit 105 controls the modulation unit 106 to perform the modulation with the retransmission modulation scheme.

As a method of determining the modulation method for retransmission, a method of multiplying the maximum rate by a predetermined constant (for example, 0.5), a method of fixing the phase modulation method such as BPSK, QPSK, or the like can be considered. .

By lowering the rate at the time of retransmission below the maximum rate, the accuracy in error correction decoding can be increased and the reception quality after retransmission can be improved. In particular, when BPSK or QPSK modulation is performed, the error rate characteristic becomes the best, and the reception quality after retransmission can be improved most efficiently.

However, when there are many multi-valued numbers at the time of new transmission,
If BPSK or QPSK is used at the time of retransmission, considerable data thinning (puncture) is required. Therefore, depending on the error correction code, it may be more advantageous to use 8PSK having a larger number of bits, although the error rate characteristic is somewhat inferior to BPSK and QPSK. For turbo codes, convolutional codes, etc., it may be better in terms of performance to reliably retransmit high likelihood bits than to retransmit a large number of low likelihood bits, so QPSK requires less energy per bit. , BPSK or 8PSK, which has a small multi-valued modulation method, is advantageous.

FIG. 2 is a diagram for explaining the relationship between the transmission packet modulation method and the reception result of the packet transmission system according to the present embodiment. FIG. 2 shows a case where an error is detected in packets A and D (NG) and other packets are correctly received (OK). In addition, in FIG.
The maximum rate modulation method in 16 is 16QAM, and the maximum rate modulation method in section 202 is 8PSK.

In the case of FIG. 2, the receiving side device transmits a NACK signal to request the transmitting side device to retransmit packets A and D. When retransmitting the packets A and D, the transmission-side apparatus modulates the packets using the QPSK modulation scheme for retransmission instead of the maximum rate modulation scheme.

As described above, by adopting a modulation method having a good error rate characteristic by using a reference different from that at the time of new transmission at the time of retransmission, it is possible to reduce the number of times of data retransmission between transmission and reception and improve the transmission efficiency. Can be achieved.

Here, the modulation method of the maximum rate input to the modulation method determination unit 105 is the one at that time (instantaneous) and changes every moment. Considering this point, the modulation scheme determination unit 105 may determine the modulation scheme for retransmission based on the result of long-term observation of the maximum rate modulation scheme.

As a concrete method of observing for a long time to determine the modulation method, the modulation method is digitized from the one having the smallest modulation multi-value number (for example, “BPSK is 0, QPSK is 1, 8
(PSK is 2, 16QAM is 3, ...), and averaging over a long period of time, and a modulation method of a numerical value closest to the average value can be used. In this case, older ones may be weighted smaller and then averaged. Also, a method of taking the histogram within a predetermined time and using the most modulation method is possible.

As described above, since the switching of the modulation method cannot be performed so fast as to follow the fading, the optimum modulation method can be set by setting the modulation method at the time of retransmission based on the result of long-term observation of the maximum rate modulation method. Since data can be retransmitted by various modulation methods, the transmission efficiency can be further improved.

In the above description, the receiving side device measures the reception quality, but the present invention is not limited to this, and T
In the DD system or the like, the transmission side device may measure the quality of the reverse line and estimate the reception quality of the reception side device.

(Embodiment 2) Embodiment 2 describes a case where the receiving side apparatus determines the modulation method. Figure 3
FIG. 6 is a block diagram showing a configuration of a packet transmission system according to a second embodiment of the present invention. In the packet transmission system shown in FIG. 3, the same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

The packet transmission system shown in FIG. 3 employs a configuration in which the transmission side device 300 has the modulation scheme decision unit 105 removed from the transmission side device 100 shown in FIG.
50 adopts a configuration in which a modulation method determination unit 351 is added to the reception side device 150 shown in FIG.

In the receiving device 350, the error detecting section 1
56 outputs an ACK signal to the transmission frame creation unit 158 and the modulation scheme determination unit 351 when no error is detected, and outputs a NACK signal to the transmission frame creation unit 158 and the modulation scheme determination unit 351 when an error is detected. Output. Reception quality measuring section 157 outputs the reception quality signal to modulation scheme determining section 351.

Modulation method determining section 351 receives ACK signal / N.
A modulation scheme is determined based on the ACK signal and the reception quality signal, and a modulation scheme signal indicating the determined modulation scheme is output to transmission frame creation section 158. The modulation method determination unit 3
As the method for determining the modulation method in 51, all the methods in the modulation method determining unit 105 described in the first embodiment can be applied. Furthermore, the modulation method determination unit 35
1 subtracts a predetermined fixed value from the SIR measured by the reception quality measuring unit 157 at the time of retransmission (when a NACK signal is input), and determines the maximum rate modulation method with the subtraction value as the modulation method at retransmission. You can also

The transmission frame creating section 158 performs framing for multiplexing the ACK signal / NACK signal and the modulation method signal on the transmission data. The transmission frame signal is transmitted to the modulator 15
Radio transmission is performed from the antenna 151 via the transmission radio unit 160, the antenna sharing unit 152.

Then, the antenna 10 of the transmitting device 300
The signal received by the antenna 8 is received by the antenna 109 and the reception radio unit 1.
10, output to the separation unit 112 via the demodulation unit 111,
The separated ACK signal / NACK signal is output to transmission signal switching section 104, and the separated modulation scheme signal is output to modulation section 106.

Transmission signal switching section 104 outputs the signal coded by error correction coding section 102 to modulation section 106 when an ACK signal is input, and outputs it to buffer 103 when a NACK signal is input. The accumulated signal is output to the modulator 106. Modulation section 106 modulates the output signal of transmission signal switching section 104 by a modulation method based on the modulation method signal, and outputs the modulated signal to transmission radio section 107.

In this way, the receiving side apparatus can also determine the modulation method at the time of retransmission based on the reception quality.

(Third Embodiment) Here, in the case of performing error correction coding with a turbo code or the like, the error correction effect becomes large only by improving the quality of only specific bits. Then, a hybrid ARQ has recently been attracting attention in which the transmitting side device selects only a specific bit at the time of retransmission and transmits the selected bit to the receiving side device, and the receiving side device combines the retransmitted signal and the already received signal to improve the performance. There is. Embodiment 3 describes a case where the present invention is applied to hybrid ARQ.

FIG. 4 is a block diagram showing the configuration of the packet transmission system according to the third embodiment of the present invention. In the packet transmission system shown in FIG. 4, the same components as those shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

The packet transmission system shown in FIG. 4 employs a configuration in which the transmission side device 400 has the puncturing section 401 added to the transmission side device 100 shown in FIG. 1, and the reception side device 450 has the reception side shown in FIG. A configuration in which a data holding unit 451 is added to the device 150 is adopted.

Separation section 112 outputs the NACK signal to transmission signal switching section 104, modulation scheme determination section 105 and puncturing section 401.

Puncturing section 401 extracts only a specific bit of the signal stored in buffer 103 and outputs it to transmission signal switching section 104 when the NACK signal is input.

Transmission signal switching section 104 outputs the signal coded by error correction coding section 102 to modulation section 106 when an ACK signal is input, and puncturing section when a NACK signal is input. The signal extracted at 401 is output to modulator 106.

The error correction decoding unit 155 performs decoding processing for error correction on the demodulated data output from the demodulation unit 154, and outputs the decoded data to the error detection unit 156 and the data holding unit 451. Also, the error correction decoding unit 155
When the NACK signal is input from the error detection unit 156, the demodulated data output from the demodulation unit 154 and the data holding unit 4
The data stored in 51 is combined with each other to perform a decoding process for error correction.

Error detection section 156 outputs a NACK signal to transmission frame creation section 158 and error correction decoding section 155 when an error is detected in the decoded data.

The data holding unit 451 is the error correction decoding unit 1
The output data of 55 is overwritten and held in the already held data.

As described above, by extracting and transmitting only specific bits at the time of retransmission, it is possible to compensate for the drawback that the data rate is lowered when transmitting by a transmission method having a good error rate characteristic. For example, when the modulation scheme at the time of new transmission is 16QAM and the modulation scheme at the time of retransmission is QPSK, it takes twice as much time as that at the time of new transmission to retransmit all data, but the amount of data to be retransmitted by puncturing is If it is halved, the time for retransmission and the time for new transmission can be made equal.

In each of the above-mentioned embodiments, only the modulation method is taken as the transmission method, and only the modulation method is made different at the time of new transmission and at the time of retransmission. However, the present invention is not limited to this, and the transmission method is not limited to this. , CDMA spreading rate, error correction code coding rate or puncture rate, etc. can be applied to all parameters that make a trade-off between transmission rate and reception quality. Although the number of bits is reduced by puncturing, half of the bits with high likelihood may make a greater contribution to the receiving side than the contribution to the receiving side when transmitting all signals by multilevel modulation. Therefore, this method is effective.

[0097]

As described above, according to the present invention,
Since data can be transmitted by a transmission method having a good error rate characteristic at the time of retransmission, the number of times of data retransmission between transmission and reception can be reduced and transmission efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a packet transmission system according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a relationship between a transmission packet modulation method and a reception result of the packet transmission system according to the above embodiment.

FIG. 3 is a block diagram showing a configuration of a packet transmission system according to a second embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a packet transmission system according to a third embodiment of the present invention.

[Explanation of symbols]

100, 300, 400 sender device 103 buffer 104 Transmission signal switching unit 105, 351 Modulation method determination unit 106, 159 Modulator 111,154 demodulation unit 112 Separator 150, 350, 450 Receiver device 155 Error correction decoding unit 156 Error detector 157 Reception quality measurement unit 158 Transmission frame creation unit 401 Puncturing part 451 data holding unit

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04L 1/16

Claims (6)

(57) [Claims] 1. A packet transmission system using ARQ
Sending device used, new data or resending according to the request from the receiving device
Data selection means to select data and new data transmission
Alternatively, when retransmitting data,
Rate setting that sets the transmission rate based on the received quality
Means and the data selected by the data selection means
Modulates to the transmission rate set by the rate setting means
The rate setting means includes a modulation means, and the rate setting means transmits the data when retransmitting the data.
Independent of the transmission rate of the new transmission of the data
A transmitting side device characterized by setting. 2. A packet transmission system using ARQ
Sending device used, new data or resending according to the request from the receiving device
Data selecting means for selecting data and the receiving side device
Rate to set the transmission rate based on the reception quality in
The data selected by the setting means and the data selecting means
Modulates the transmission rate set by the rate setting means
And a rate setting means for receiving the new data when transmitting the new data.
Maximum rate at which the desired quality can be obtained in the side device
When the data is retransmitted, the receiving side
The maximum rate at which the desired quality can be obtained in the device
The transmission side equipment characterized by setting a lower rate than
Place 3. The rate setting means receives the data when the data is retransmitted.
A fixed rate is set to the maximum rate to obtain the desired quality in the receiving device.
It is characterized by setting a rate calculated by multiplying by a number
The transmission-side device according to claim 2. 4. The method according to any one of claims 1 to 3.
A base station apparatus comprising: 5. The method according to any one of claims 1 to 3.
A communication terminal device characterized by comprising:
Place 6. A packet transmission system using ARQ
A packet transmission method of a transmitting side device used, in which new data or retransmission is performed according to a request from the receiving side device.
The data selection step of selecting data and the receiving side device
Rate to set the transmission rate based on the reception quality in
Data selected in the setting process and the data selection process
Modulates the transmission rate set in the rate setting step
And a rate setting step for transmitting new data.
Maximum rate at which the desired quality can be obtained in the side device
When the data is retransmitted, the receiving side
The maximum rate at which the desired quality can be obtained in the device
Packet transmission characterized by setting a lower rate than
How to send.