Radio communication device and method of controlling transmission rate

(54) Title: TRANSMISSION RATE CONTROL DEVICE, BASE STATION DEVICE AND TRANSMISSION RATE CONTROL METHOD (51) Int.CI .: H04B 1/40; 1/707 H04B; H04B 7/005; H04J 13/00; H04L 1/00; H04W 16/28; H04W 28/18; H04W 28/22; H04W 36/04; H04W 52/26; H04W 52/54; H04W 72/04; H04W 72/08; H04W 16/14; H04W 24/00 (52) CPC: H04L 1/0002; H04L 1/0003; H04W 28/22; H04W 52/24; H04W 52/265; H04W 52/267; H04W 72/085; H04L 1/0025; H04L 1/0026; H04W 16/14; H04W 24/00; H04W 72/0406; H04W 72/0413 (30) Unionist Priority: 4/17/1998 JP 10-107300 (73) Holder (s): PANASONIC CORPORATION (72) Invoice (s): TOYOKI UE, KATSUHIKO HIRAMATSU, OSAMU KATO

1/27

Descriptive Report of the Invention Patent for TRANSMISSION RATE CONTROL DEVICE, BASE STATION DEVICE AND TRANSMISSION RATE CONTROL METHOD.

Technical Field

The present invention relates to a radio communication device with variable baud rate and a baud rate control method.

Fundamentals of Technique

A conventional radio communication device is explained using a Performance of SIR-Based Transmit Power Control document using Outer Loop in the Forward Link of DS-CDMA (IEICE TECHNICAL REPORT AP96-148, EMCJ96-83, RCS96-162, MW96- 188 (1997-02) .This document describes a method of controlling transmission power in CDMA. The following is an explanation of this description.

In the control of the transmission power, the SIR measurement is performed, indicating the reception quality and increase / decrease in the reception quality in each groove cycle (0.625 mm). In this case, if the measured SIR is greater than the SIR target a command is sent to reduce the transmission power to the base station (transmission side) and if the measured value is less than the SIR target a command is sent to increase the transmission power to the base station. The base station increases or decreases the transmit power according to this command.

Furthermore, the base station controls the external circuit taking into account the fact that the SIR goal to acquire the required quality (FER: Structure Error Regime) varies depending on the environment of a mobile station. To be more specific, FER is measured from decoded data. This FER is compared with the FER target in all the different structures and if the measured value is higher, the SIR target is increased and if the measured value is lower the SIR target is reduced.

The prior art performs transmission power control not only by sending a transmission power control command

2/27 for the transmission side based on the SIR measured by the mobile station but also changing the SIR target by controlling the external circuit.

However, the prior art has the following problem. That is, the SIR target increases depending on the environment and transmission rate of the mobile station and the SIR reception sometimes decreases due to the fading of the signal etc. In such a case, the mobile station instructs the base station to increase the transmit power to bring the SIR reception closer to the SIR target, considerably increasing the transmit power from the base station to the mobile station, which is similar to increasing interference with other mobile stations to an intolerable degree.

Disclosure Of Invention

It is an object of the present invention to provide a radio communication apparatus and transmission rate control method capable of controlling the transmission power of a base station directed to a mobile station appropriately without being affected by the environment of the mobile station or rate of transmission. streaming.

This objective is achieved by a radio communication device and a transmission rate control method that switches the transmission rate of a transmission signal based on the reception quality information from the other communication end, or according to the communication environment. other communication end and transmits the signals at the switched baud rate.

Brief Description Of Drawings

FIG. 1 is a block diagram showing a configuration of a base station apparatus in accordance with Mode 1 of the present invention;

FIG. 2 is a block diagram showing a configuration of a communication terminal apparatus that performs radio communication with the base station apparatus in accordance with the above embodiment;

FIG. 3 is a block diagram to explain a method of

3/27 measure of desired signal reception power in the above communication terminal device;

FIG. 4 is a block diagram to explain a method of measuring the signal to interference plus noise ratio in the above communication terminal;

FIG. 5 is a diagram to explain a signal-to-noise interference method on the above communication terminal;

FIG. 6 is a configuration diagram of the data structure used in communication by the base station apparatus of the present invention;

FIG. 7 is another configuration diagram of the data structure used in communication by the base station apparatus of the present invention;

FIG. 8 is a sequence diagram between the base station apparatus and the communication terminal apparatus of the present invention;

FIG. 9 is another sequence diagram between the base station apparatus and the communication terminal apparatus of the present invention;

FIG. 10 is another sequence diagram between the base station apparatus and the communication terminal apparatus of the present invention;

FIG. 11 is another sequence diagram between the base station apparatus and the terminal communication apparatus of the present invention;

FIG. 12 is a flow chart to explain the method of switching baud rate on the base station apparatus according to the above embodiment;

FIG. 13 is another flowchart to explain the transmission rate switching method on the base station apparatus according to the above modality;

FIG. 14 is another flowchart to explain the transmission rate switching method on the base station apparatus according to the above modality;

FIG. 15 is another flowchart for explaining the baud rate method 4/27 on the base station apparatus according to the above embodiment;

FIG. 16 is a block diagram showing a configuration of a base station apparatus according to Mode 2 for the present invention;

FIG. 17 is a block diagram showing a configuration of a communication terminal apparatus which performs radio communication with the base station apparatus according to the above embodiment;

FIG. 18 is a block diagram for explaining a method of measuring desired signal reception power in the above communication terminal apparatus;

FIG. 19 is a block diagram to explain a method of measuring the signal to interference plus noise ratio in the above communication terminal;

FIG. 20 is a flow chart to explain a method of switching baud rate on the base station apparatus according to the above embodiment;

FIG. 21 is another flowchart to explain the transmission rate switching method on the base station apparatus according to the above modality;

FIG. 22 is another flowchart to explain the transmission rate switching method on the base station apparatus according to the above modality;

FIG. 23 is another flowchart to explain the transmission rate switching method on the base station apparatus according to the above modality;

FIG. 24 is another flowchart to explain the transmission rate switching method on the base station apparatus according to the above modality;

FIG. 25 is another flow chart to explain the baud rate switching method on the base station apparatus according to

5/27 with the above modality;

FIG. 26 is another flow chart to explain the transmission rate switching method in the base station apparatus according to the above embodiment;

FIG. 27 is another flow chart to explain the transmission rate switching method in the base station apparatus according to the above modality;

FIG. 28 is a diagram for explaining the transmission rate control between layers in the base station apparatus of the present invention; and

FIG. 29 is a flow chart to explain the control of the baud rate between layers in the base station apparatus of the present invention.

Best Ways to Carry Out the Invention

Referring now to the accompanying drawings, the modalities of the present invention are explained in detail below.

(Mode 1)

FIG. 1 is a block diagram showing a configuration of a base station apparatus in accordance with Mode 1 of the present invention. In this base station apparatus, a signal received from antenna 101 is sent to RF reception circuit 103 via duplicator 102 to use the same antenna for both transmission and reception. In the RF receiving circuit 103, the receiving signal is amplified and converted to an intermediate frequency or a baseband frequency.

The converted frequency signal is demodulated by demodulator 104. The demodulation result is sent to separator 105, where it is separated into reception and signal data for transmission rate switching control.

The baud rate switch controller 106 sends a baud rate switch signal to baud generator 107 based on the received control signal. The operation of the baud rate switching control circuit will be explained later.

In relation to the transmission, the transmission data is modulated by the modulator 108 and sent to the RF transmission circuit 109. The RF transmission circuit 109 converts the frequency of the transmission data and then amplifies it. This transmission signal is sent from antenna 101 via duplicator 102.

FIG. 2 is a block diagram showing a configuration of a terminal communication device that performs radio communication with the base station apparatus according to embodiment 1 of the present invention.

A signal received from antenna 201 is sent to RF reception circuit 203 via duplicator 202 to use the same antenna for transmission, where it is amplified and converted to an intermediate frequency or a baseband frequency. The converted frequency signal is demodulated by demodulator 204. At the same time, the output signal from the RF reception circuit is sent to reception quality measurement circuit 205 where reception quality is measured.

This reception quality includes, for example, received signal strength, desired signal reception power, Signal to Interference Ratio (SIR),

Signal Ratio for Interference plus Noise (here after abbreviated as SINR). The intensity of the received signal is obtained by measuring the RF reception power. Using the received signal strength makes the circuit configuration simpler and allows use in an environment free from interference signals.

The reception power of a desired signal is measured by multiplying the reception signal by a known signal. In this case, if there is an interference signal, using the intensity of the signal received alone, it would end up reporting the reception power of the desired signal and the interference signal, and this would mean that the reception power required by the terminal, it is desirable to use SINR as the quality of reception that is the

7/27 main reliable information as an index to determine an error regime characteristic.

It is shown in FIG. 3 a measurement circuit for the desired signal receiving power. This circuit extracts the known standard component of the reception signal; the complex conjugate circuit 302 performs a complex conjugate operation on the known pattern maintained by the base station; the complex multiplication circuit 301 performs complex multiplication on the known standard component of the reception signal and the known standard subjected to the complex conjugate operation and calculates the position of the desired reception signal on the complex plane (position of the black circle in FIG. 5); and the power measurement circuit 303 measures the power from this calculation result.

On the other hand it is shown in FIG. 4 a SINR measurement circuit. This circuit extracts the known pattern component from the reception signal; the complex conjugate circuit 402 performs a complex conjugate operation on the known pattern maintained by the base station; the complex multiplication circuit 401 performs complex multiplication on the known standard component of the reception signal and the known standard subjected to the complex conjugate operation and calculates the position of the desired reception signal on the complex plane (position of the black circle in FIG. 5); and the power is measured from this calculation result. Furthermore, the interference signal + noise 404 power measurement circuit measures the interference signal + noise power from an average value of the vector sum of squares between the position of each reception signal (position of the white circle in the FIG. 5) and position of the desired reception signal (position of the black circle in FIG. 5). Furthermore, the desired power measurement circuit 403 measures the desired power of the result of the calculation above. Then, the 405 ratio calculation circuit calculates the relationship between the output of the interference signal + 404 noise power measurement circuit and the output of the desired power measurement circuit 403. The SINR is calculated from this.

The result of the reception quality measurement calculated from 8/27 to the form is sent to the multiplier circuit 206. The multiplex circuit 206 assigns the transmission data resulting from the reception quality measure to a transmission slot. The modulation circuit 207 modulates such transmission data and the RF transmission circuit 208 converts the frequency and amplifies. This transmission signal is sent from antenna 201 via duplicator 202.

Here, it is explained how the baud rate switching information is reported from the communication terminal device to the base station device. There are two types of reports: reporting all the time and reporting on an as-needed basis. Since the first method performs reporting all the time, it can switch the baud rate with high precision but the amount of communication increases.

In the case of voice communications, the voice information (message) is often transmitted multiplexed with information control in a slot as shown in FIG. 6. Therefore, reporting at all times is possible on voice communications or low-speed data communications.

In the latter method, only a small amount of communication is required because the report is done only when required. It is desirable to use this method for packet communications to perform high-speed data communications. In packet communications, information is sent intermittently in a short time. Thus, as shown in FIG 7 (a) and FIG. 7 (b), the information control is not multiplexed in a slot but a flag is used to indicate whether it is a control message or information. FIG. 7 (a) shows a case where the flag is attached to indicate a message. FIG. 7 (b) shows a case where a flag is attached to indicate information control.

Then, it is explained, the regulation to switch the transmission rate. There are four methods of regulation to switch the baud rate:

The first method is explained in using FIG. 8. While the transmitting terminal device is measuring reception quality,

9/27 there are times when the quality of reception deteriorates dramatically. In a mobile communication environment, in the case of non-line-of-sight (non-LOS) communication called shading, for example, the received signal strength decreases dramatically by 10 dB or more. While monitoring such a situation, a report is made when the quality of reception deteriorates dramatically. Upon receipt of this reception quality report, the base station handset switches the transmission rate. When the quality of reception improves, which is measured periodically on the side of the communication terminal or by a demand from the base station, the base station apparatus switches the transmission rate to the original transmission rate. The regulation in which the quality of reception deteriorates or improves dramatically can be detected by making a judgment about the quality of reception, such as reception field density, for example.

Then, the second method is explained using FIG. 9. The base station device measures reception quality. If the quality deteriorates dramatically this can be determined as non-LOS communication called shading. Shading is determined by the position of the antenna of the communication terminal device and the antenna of the base station device and is not affected by differences in the carrier frequency. Therefore, in such a case, it is possible that the reception quality will also drastically deteriorate in the communication terminal device. Thus, the base station device sends a request to report the reception quality to the communication terminal device. The communication terminal device measures the reception quality and reports it to the base station device. The base station device controls the transmission rate switching according to the reported reception quality. When the quality of reception improves, which is measured periodically on the side of the communication terminal or by a demand from the base station, the base station apparatus switches the transmission rate to the original transmission rate. The regulation in which the reception quality deteriorates or improves dramatically can be detected by judging 10/27 limit on the reception quality, intensity of the received signal, for example.

Then, the third method is explained using FIG. 10. If there is an error in the message received, the communication terminal device issues a retransmission request. The base station handset sends a request to report the reception quality to the communication terminal device when the communication terminal device issues a retransmission request. The communication terminal device measures the reception quality and reports it to the base station device. The base station device controls the transmission rate switching according to the reported reception quality. For example, if the reported reception quality measured by the communication terminal device is less than a predetermined value, the base station device switches the transmission rate. When the quality of reception improves, which is measured periodically on the side of the communication terminal or by demand from the base station, the base station apparatus switches the transmission rate to the original transmission rate. The regulation in which the quality of reception deteriorates or improves dramatically can be detected by performing a limit judgment on the quality of reception, intensity of the signal received, for example.

Then, the fourth method is explained using FIG. 11.0 base station handset monitors the transmission power of itself. The base station device controls the transmit power based on a transmit power control signal sent from the communication terminal device, and if the quality of the transmission from the base station device to the communication terminal deteriorates the device communication terminal requires an increase in transmission power. If this request is deemed to be excessive transmission power taking into account the amount of interference with others, the base station device performs the transmission rate switching control. The judgment of excessive transmission power can be carried out, for example by limit judgment. Furthermore, if a pre-terminated 11/27 available amount of transmit power has been secured then the base station apparatus switches the baud rate to the original baud rate. This predetermined amount of available transmission power is determined appropriately according to the amount of the controlled transmission rate. For example, if the baud rate is reduced to 1/2, the baud rate is switched when at least an available amount of 3 dB has been secured.

By the way, combining some of the four methods above, you can eliminate delays in switching the baud rate and perform delicate control.

Thus, the result of the measurement of reception quality of the signal transmitted down the line from the base station apparatus shown in FIG. 1 is measured by the terminal communication device in FIG. 2 and reported to the base station line above. The base station switches the transmission rate based on the reception quality measured on the above line by the transmitting terminal device.

Here, the transmission rate switching control circuit operation is explained in detail. FIG. 12 is a flow chart of the baud rate control circuit. In ST11 the base station device compares the result of the reception quality measurement reported from the limit 1 communication terminal device. Here, a case is explained when the SIR with reception quality is used, but the same applies when the received signal strength, the desired signal reception power, or the SINR is used. This limit 1 is fixed according to the transmission rate, but in a CDMA communication system. It is fixed according to the spreading factor or the number of multiplexing codes.

If the result of the reception quality measurement (SIR) is greater than limit 1, the same transmission rate is used. If the SIR is less than limit 1, the channel condition is determined to be poor and the baud rate is changed to a baud rate of 1/2 (ST12).

Even more, as shown in FIG. 13, the station apparatus

12/27 base compares the result of the reception quality measurement reported from the communication device with limit 1 (ST21) and if the SIR is greater than the limit 1, the same transmission rate is used. If the SIR is less than the limit 1, the transmission rate is switched to such a transmission rate that the SIR is greater than the limit 1 (ST22). In CDMA, the spreading factor is switched. Thus, the SIR exceeds limit 1 and more precise control can be performed by varying the quality of reception. This makes it possible to improve the reception quality of the other communication end even if the condition of the communication path with the other communication end deteriorates dramatically and reduces the amount of interference with others because the reception quality goal is reduced and the transmission power is reduced. Therefore, it is possible to increase the effect of switching the baud rate.

Even more, as shown in FIG. 14 the base station device compares the reception quality measurement result reported from the limit 2 communication terminal device (ST31) and if the SIR is less than limit 2, the same transmission rate is used and if the SIR is greater than limit 2, the channel condition is determined to be good and the transmission rate is switched to a double transmission rate (spread factor 1/2) (ST32). Here, limit 2 corresponds to a double transmission rate and is fixed higher than limit 1. Thus, while the channel condition is good, the transmission rate is increased to transmit as much data as possible. That is, if the condition of the communication path with the other communication end is good, faster transmission is possible while maintaining the reception quality of the other communication end. However, because the transmission power does not increase, interference with others does not increase.

Even more, as shown in FIG. 15, limit n is fixed (ST41) and the base station apparatus compares the reception quality measurement result reported from the n-limit communication terminal device (ST42). If the SIR is less than the η limit, the n limit is switched to the n + 1 limit corresponding to the next highest transmission rate

Fast 13/27 (ST43). If the SIR is greater than the limit n, the umpteenth fastest transmission rate (spreading factor) is fixed (ST44). That is, the transmission rate is switched to such a transmission rate that the CRS is fixed at a value between the limit n and the limit n + 1 corresponding to the two transmission regimes. Limit n corresponds to the umpteenth fastest transmission rate and is greater than limit n + 1. In this case, faster transmission is possible, on the condition that the reception quality is satisfied. This allows more precise control over the baud rate according to the channel condition.

Using such a method, it is possible to switch the transmission rate of the base station according to the reception quality of the communication terminal device. This not only prevents the reception quality at the other end from continuing to be poor, but also reduces transmission power because the reception quality target reduces, which reduces interference with others. Therefore, it is possible to control the transmission power from the base station to the communication terminal device appropriately without being affected by the environment of the communication terminal device and transmission speed.

(Mode 2)

FIG. 16 is a block diagram showing a configuration of a base station apparatus according to Mode 2 of the present invention;

In this base station apparatus, a signal received from antenna 101 is sent to RF reception circuit 103 via duplicator 102 to use the same antenna for both transmission and reception. In the RF receiving circuit 103, the receiving signal is amplified and converted to an intermediate frequency or a baseband frequency.

The converted frequency signal is demodulated by demodulator 104. The demodulation result is sent to separator 105, where it is separated into reception and signal data for transmission power control.

14/27

The baud rate switch controller 106 sends a baud rate switch signal to baud generator 107 based on the baud rate control signal. The operation of the baud rate switching control circuit will be explained later.

With respect to transmission, the transmission data is modulated by the modulator circuit 108 and sent to the RF transmission circuit 109. The RF transmission circuit 109 converts the frequency of the transmission data. This transmission signal is sent from antenna 101 via duplicator 102.

FIG. 17 is a block diagram showing a configuration of a terminal communication device that performs radio communication with the base station apparatus according to embodiment 2 of the present invention.

A signal received from antenna 201 is sent to RF reception circuit 203 via duplicator 202 to use the same antenna for both transmission and reception, where it is amplified and converted to an intermediate frequency or a baseband frequency. The converted frequency signal is demodulated by demodulator 204. At the same time, the output signal from the RF receiving circuit is sent to the transmission power control value calculation circuit 205 where the transmission power control signal is determined.

This transmit power control signal includes, for example, received signal strength, desired signal reception power, signal to interference ratio (SIR), and signal to interference plus noise ratio. Furthermore, regarding the amount of information sent as a transmission power signal, there are cases with 2 pieces of information about increasing / decreasing the transmission power, 3 pieces of information about increasing / maintaining / decreasing the transmission power, 4 pieces of information with more detailed fixations of the control quantity than the cases above.

First, the case where information control consists of 2

15/27 pieces of information is explained. If the received signal strength is based, the RF reception power is measured. If the measured power is greater than a limit, a control signal is generated so that the transmission power from the base station is reduced and if the power is less than the limit, a control signal is created that the transmission power from the base station is increased. Such a method based on the received signal strength was the simplest circuit configuration. Furthermore, this method can be used in an environment where there is no sign of interference.

If the desired signal reception power is based, the reception signal is measured by multiplying the reception signal by a known signal. If there is an interference signal, using the received signal strength alone would not mean that the reception power of the desired signal and that of the interference signal were reported. Therefore, it is necessary to measure and report the reception power of the desired signal required by the communication terminal device. Thus, it is desirable to use the SINR as a quality of reception, which is the most reliable information as an index to detect error regime characteristics.

The desired signal receiving power measurement circuit is shown in FIG. 18. This circuit extracts the known pattern component from the reception signal; the complex conjugate circuit 302 performs a complex conjugate operation on the known pattern maintained by the base station; the complex multiplication circuit 301 performs complex multiplication and calculates the position of the desired reception signal in the complex plane (position of the black circle in FIG. 5); and the power measurement circuit 303 measures the power from this calculation result. If the power measured by the comparison circuit 1801 is greater than limit 3, a control signal is generated so that the transmission power from the base station is reduced and if the measured power is less than limit 3, and the control signal is generated so that the transmission power from the base station is increased.

On the other hand it is shown in FIG. 19 a measurement circuit

16/27

SINR. This circuit extracts the known pattern component from the reception signal; the complex conjugate circuit 402 performs a complex conjugate operation on the known pattern maintained by the base station; the complex multiplication circuit 401 performs complex multiplication over the known standard component of the reception signal in the complex plane (position of the black circle in FIG. 5); and the power is measured based on this calculation result. Furthermore, the interference signal + noise 404 power measurement circuit measures the interference signal + noise power from an average value of the vector sum of squares between the position of each reception signal (position of the white circle in the FIG. 5) and position of the desired reception signal (position of the black circle in FIG. 5). Furthermore, the desired power measurement circuit 403 measures the desired power. Then, the ratio calculation circuit 405 calculates the relationship between the output of the power measurement circuit of the interference signal + noise 404, and the output of the desired power measurement circuit 403. If the power ratio measured by comparison circuit 1901 is greater than limit 3, a control signal is generated so that the transmission power from the base station is reduced and if the measured power is less than limit 3 , and the control signal is generated so that the transmission power from the base station is increased.

Then, the case where the control information has 3 pieces of information is explained. In the case of 3 pieces of information, limit 3 and limit 4 which is greater than limit 3, are used as limits. If the measured power ratio is less than limit 3, a control signal is generated so that the transmission power from the base station is increased. If the measured power ratio is greater than limit 3, and less than limit 4, a control signal is generated so that the transmission power from the base station is retained. If the measured power ratio is greater than limit 4, a control signal is generated so that the transmission power from the base station is reduced.

Furthermore, if the control information has 4 or more pieces of information, the number of limits is set to (number of pieces of control information -1 / 27) to determine control information divided into smaller pieces through judgment of limit based on the comparison between a plurality of limits.

Transmission power control information calculated in this way is sent to multiplier circuit 206. Multiplier circuit 206 assigns transmission data and transmission power control information to a transmission slot. The modulation circuit 207 modulates such transmission data and the RF transmission circuit 208 converts the frequency and amplifies the transmission data. This transmission signal is sent from antenna 201 via duplicator 202.

Thus, the transmit power control signal based on the reception quality of the transmitted downlink signal from the base station apparatus shown in FIG. 16 is generated by the communication terminal device shown in FIG. 17 and reported to the uplink base station apparatus. The base station switches the baud rate based on the transmit power control signal measured by the communication terminal received on the uplink.

Here, the operation of the transmission rate switching control circuit is explained in detail. FIG. 20 is a flow chart of the baud rate switching control circuit. The base station device estimates the reception quality by accumulating the transmission power control information reported from the communication terminal device (ST51) and compares it with limit 1 (ST52). This limit 1 is fixed according to the transmission rate but in the CDMA communication system, it is fixed according to the spreading factor or the number of multiplexing codes.

If the estimated reception quality value (estimated SIR value) is greater than threshold 1, the channel condition is determined to be good and the same transmission rate is used. If the estimated SIR value is greater than threshold 1, the channel condition is determined to be poor and the rate

18/27 transmission rate is changed to a transmission rate of 1/2 (spreading factor x 2) (ST53).

Thus, the transmission rate is switched based on the channel estimation result, making it possible to reduce interference with others. Furthermore, the use of the transmit power control bit for channel estimation can reduce the amount of information to be sent from the other end of the communication without the need for special control information about the transmission rate control.

Even more, as shown in FIG. 21, the base station device estimates the reception quality by accumulating the transmission power control information reported from the communication terminal device (ST61) and compares it with limit 1 (ST62). If the estimated SIR value is greater than limit 1, the channel condition is determined to be good and the same baud rate is used. If the estimated value of the SIR is less than limit 1, the channel condition is determined to be poor and the SIR can be changed to such a transmission rate that the SIR is greater than limit 1 (ST63). This allows more precise control during the reception quality variation. That is, it is possible to not only improve the quality of reception at the other end of the communication even if the channel condition with the other end of the communication deteriorates dramatically but also to reduce the transmission power because it reduces the goal of reception quality, also reducing interference with others. Therefore, it is possible to increase the transmission rate switching effect.

As shown in FIG. 22 the base station device forms the reception quality by accumulating the power control information reported from the communication terminal device (ST71) and compares it to limit 2 (ST72). If the estimated SIR value is less than limit 2, the channel condition is determined to be poor and the same baud rate is used. If the estimated SIR value is greater than limit 2, the channel condition is determined to be good and the baud rate can be switched to a double baud rate (spread factor 1/2)

19/27 (ST73). Limit 2 corresponds to a double transmission rate and is greater than limit 1.

In this way, while the condition of the channel is good, the transmission rate is increased to transmit as much data as possible. That is, if the channel condition with the other communication end is good, faster transmission is possible while maintaining the reception quality of the other communication end. In fact, because the transmission power is not increased, interference with others does not increase.

As shown in FIG. 23, the base station device estimates (ST82) the quality of reception by accumulating the transmission power control information reported from the terminal communication device, setting a limit n (ST81) and comparing it with limit n (ST84) . If the estimated SIR value is less than the η limit, the n limit is changed to the n + 1 limit which corresponds to the next fastest transmission rate (ST83). If the estimated value of the SIR is greater than the limit n, the umpteenth fastest transmission rate (spreading factor) (ST85) is fixed. That is, a transmission rate is selected in such a way that the estimated SIR value is between the limit n and the limit n + 1 corresponding to two transmission regimes. Limit n corresponds to the umpteenth fastest transmission rate and is greater than limit n + 1. In this case, faster transmission is possible, on the condition that the reception quality is satisfied. This allows more precise control over the baud rate according to the channel condition.

In addition, the operation of another transmission rate switching control circuit is explained. As shown in FIG. 24, for example the base station apparatus the required transmit power based on the transmit power control information reported from the communication terminal device. This transmission power is compared with limit 4 (ST91).

This limit 4 is determined according to the amount of interference with others generated by increasing the limit value of the

20/27 transmitter transmission. Limit 4 is also fixed according to the transmission rate, but in the CDMA communication system it is fixed according to the spreading factor or the number of multiplexing codes. That is, if the transmission is carried out with X16 spreading or X256 spreading, there is a difference of X16 in terms of spreading factor and thus the X16 spreading power limit is 16 times the X256 spreading power limit. . The same applies to the number of multiplexing codes.

If the transmission power is less than limit 4, the same transmission rate is used. If the transmission power is greater than limit 4, the interference with others is determined to be large and the same transmission is switched to a transmission rate of 1/2 (spread factor X2) (ST92). This allows for optimal or faster transmission on the condition that interference with others is within the allowable range.

In addition, as shown in FIG. 25, the base station apparatus determines the required transmit power based on the reported transmit power control information from the communication terminal device. This transmission power is compared with limit 4 (ST101). And if the transmission power is less than limit 4, the same transmission rate is used and if the transmission power is greater than limit 4, interference with others is determined to be large and the transmission rate (spreading factor ) is selected so that the transmission rate is less than limit 4 (ST102). This can prevent it from generating an excessive amount of interference.

In addition, as shown in FIG. 26, the base station apparatus determines the required transmit power based on the transmit power control information reported from the communication terminal device. This transmission power is compared with limit 5 (ST111) and if the transmission power is greater than limit 5 the same transmission rate is used and if the transmission power is less than limit 5, interference with others is determined to be small and the

21/27 baud rate can be switched to a double baud rate ( ¹/>) (ST112). Here limit 5 corresponds to a double transmission rate and is lower than limit 4.

In addition, as shown in FIG. 27, limit n is fixed (ST121) and the base station device compares the transmission power based on the transmission power control information reported from the n-limit communication terminal device (ST123). If the transmission power is greater than the η limit, the n limit is changed to the n + 1 limit which corresponds to the next fastest transmission rate (ST122). If the transmission power is greater than the limit n, the umpteenth fastest transmission rate (spreading factor) is fixed (ST124). That is, a transmission rate is selected so that the transmission power is a value between the limit n and the limit n + 1 corresponding to the two transmission regimes. Limit n corresponds to the umpteenth fastest transmission rate and is less than the limit n + 1. In this case, faster transmission is possible, under the condition that the amount of interference with others is controlled within a certain range.

In addition, the base station sets the transmission power in several ways: transmitting with the transmission power before switching each time the transmission rate is switched, transmitting with the transmission power before switching reduced by a certain amount and transmitting with the transmission power before switching increased by a certain value.

The first method is valid to reliably improve the communication quality for the terminal. In the configuration of the present mode, a transmission power control signal input to the transmission rate switching control circuit 106 can be sent to RF transmission circuit 109. RF transmission circuit 109 controls the increase / decrease in transmission power based on the transmission power control signal.

The second method is a method of fixing the transmission power by subtracting a certain value from the transmission power when switching the transmission rate. This is because the transmission power possibly reaches a large value when the channel is optimized for the terminal, generating great interference with other terminals. In this embodiment of the mode, the transmission power control signal input to the transmission rate switching control circuit 106 can be changed to such a control signal that the transmission power is reduced by a certain value when switching the transmission rate. The RF transmission circuit 109 controls the increase / decrease of the transmission power based on the transmission power control signal. In this case, the cumulative value of the transmission power control also needs to be reduced by a certain amount.

The third method is a method of increasing transmission power within the permissible range of interference with others and is valid for improving the quality of the communication. In the configuration of this mode, the transmission power control signal input to the transmission rate switching control circuit 106 can be changed to such a control signal that the transmission power is increased by a certain value when the rate transmission is switched. In this case, the cumulative value of the transmission power control also needs to be increased by a certain amount.

To decrease a certain value, in the CDMA system, for example, the transmission with reduced power by 3dB allows an additional communication terminal device communicating with a similar spreading factor.

In addition, together with the transmission power control information, the reception quality information can also be reported from the communication terminal device using the method explained in Mode 1. The method of reporting from a communication terminal device to the base station handset and its synchronization are the same as those in Mode 1.

The control of the transmission rate switching is normally performed based on the accumulated value of the

23/27 transmission power and if the reception quality on the side of the communication terminal device deteriorates dramatically, the reception quality information is reported from the communication terminal device to the base station device and the base station device base performs the control of the baud rate switching.

In addition, the base station device sends a reception quality measurement request to the communication terminal device at the time the communication terminal device generates a request to resend ARQ control information, etc., and the device communication terminal measures reception quality and reports it to the base station handset. The base station apparatus performs transmission rate switching based on the reported transmission quality.

Then, the control between layers is explained in the transmission rate control method, described in modalities 1 and 2 above. FIG.28 is a diagram to explain how the baud rate is controlled between layers.

In this control, as shown in FIG.28, the allowable transmission power (Pallow) fixed in a layer 3 radio resource control (RRC) layer is sent to layer 1 (physical layer). In layer 1, the average transmission power is compared with the allowable transmission power (Pallow). Then, a message (MPHY-STATUS) such as allowable transmit power has been reached or intermediate transmit power has been exceeded or Average transmit power is X dB below the allowable transmit power, is indicated by layer 1 for the control layer of intermediate access (MAC) layer 2. The allowable transmission power is appropriately set by the radio resource control layer (layer 3) according to the system load such as the traffic condition.

Here, the message allowable transmit power has been reached or allowable transmit power has been exceeded indicates that the channel condition is determined to be bad and it is necessary to decrease the

24/27 baud rate. On the other hand, the message average transmission power is X dB below the allowable transmission power indicates that the channel condition is recovered and the transmission rate can be increased.

Control details are explained using FIG.29. Here, a case with downlink is explained. First, the radio resource control layer monitors the downlink traffic condition and determines the initial transmission rate on the downlink through negotiation between the radio resource control layer (layer 3) and the radio control layer. intermediate access (layer 2). Then, a communication is initiated.

During a communication, in ST131, at least one intermediate transmission power structure (PAVE) is monitored in layer 1. The transmission rate is controlled according to this channel condition.

First, this intermediate transmission power (PAVE) is compared with the allowable transmission power (PALLOW) and the difference between these two (D = PALLOW - PAVE) is obtained. Then, in ST132, it is determined whether the intermediate transmission power (PAVE) exceeds the permissible transmission power (PALLOW) or not. If the intermediate transmit power (PAVE) exceeds the allowable transmit power (PALLOW), a message allowable transmit power has been reached or allowable transmit power has been exceeded is indicated in ST 133.

According to this message, the transmission rate is decreased in the intermediate access control layer (layer 2) and the total transmission power (intermediate) is reduced in layer 1. This reduces interference with other communication terminals.

If the intermediate transmission power (PAVE) does not exceed the allowable transmission power (PALLOW), it is determined whether the difference is at least a predetermined value (Pstep) in ST134. This Pstep is a power step corresponding to the difference between the modified mission rate25 / 27 and the original transmission rate when the transmission rate is decreased.

If the difference (D) between the intermediate transmission power (PAVE) and the allowable transmission power (PALLOW) is less than the predetermined value (Pstep), the same transmission rate is used. If the difference (D) between the intermediate transmission power (PAVE) and the permissible transmission power (PALLOW) is greater than the predetermined value (Pstep), layer 1 indicates the message intermediate transmission power is X dB below the power transmission allowable in ST135. Then, according to this message, the intermediate access control layer (layer 2) increases the transmission rate and layer 1 increases the total transmission power within the X dB range. This makes it possible to immediately send the transmission signal that has been stored due to the decreased transmission rate.

In FIG.29, it is only determined whether the transmission rate is increased or maintained or decreased, but the judgment is not limited to this; it is also possible to freely set a control to make the transmission rate variable beyond this limitation.

Then, a case is explained where the control of the transmission rate previously mentioned is actually performed. In accordance with the existing method of modifying the baud rate, the downlink is designated for group transmission and the uplink is designated for continuous transmission. For this reason, the transmission rate is modified accordingly. That is, the transmission power itself is not modified in the downlink and, for example, transmission is carried out only in the first half of a structure, and in the uplink the transmission power is decreased and the transmission is carried out through a combining regime without penetrating the structure. The intermediate access control layer (layer 2) selects the transmission rate among a set of regimes specified by the radio resource control layer (layer 3). At this point, the physical layer (layer 1) creates and adds a word indicating the current transmission rate as instructed

26/27 by the intermediate access control layer (layer 2).

In addition, when each base station separately controls the transmission rate above, negotiation is required when diversity of handover occurs. For example, a method by which all base stations select a specific baud rate, through negotiation at the top layer, and another method by which no baud rate control is performed during handover diversity, are possible examples of this.

The above explanation describes the case where the parameter monitored at layer 1 is the transmit power, but FER, SIR or the interference power can also be used as the parameter monitored at layer 1.

The above explanation describes the case where the baud rate control shown in FIG. 29 is performed on the downlink, but the baud rate control shown in FIG.29 can also be applied to the uplink.

Downlink baud rate control is used to reduce interference with others, but uplink baud rate control is not only used to reduce interference with others, but is also used to achieve power savings or when there are equipment restrictions.

The modalities 1 and 2 above, describe the apparatus shown in FIG. 1 and FIG. 16 as the base station apparatus and the apparatus shown in FIG.2 and FIG. 17 as the communication terminal device, but the present invention is also applicable to the case where the device shown in FIG.1 and FIG.16 is the communication terminal device and the device shown in FIG.2 and FIG. 17 is the base station apparatus.

In addition, modes 1 and 2 describe the case with a baud rate set to 2x or 1/2, but in the present invention, the baud rate can also be set to other extensions according to various conditions.

As explained above, on the radio communication device and

27/27 transmission rate control method of the present invention, the base station can switch the base station's transmission rate, based on a base station's transmit power control signal that the terminal determined by measuring quality reception. This allows appropriate control by the base station over the transmission power to the mobile station without being affected by the mobile station's environment or transmission speed.

This application is based on Japanese patent application no. HEI 10-107300, the complete content of which is expressly incorporated herein by reference.

Industrial Applicability

The present invention is applicable to a base station device and a terminal communication device in a digital radio communication system.

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