KR20060026375A - Apparatus and method for determining rate of reverse link in a mobile communication system - Google Patents

Abstract

The present invention relates to an apparatus and a method for determining a reverse rate in a mobile communication system, an apparatus capable of reducing time delay and efficient in controlling reverse rate by applying grant information and common rate control information in a mobile communication system; Provide a method.

A method according to an embodiment of the present invention is a method for determining a reverse data rate in a mobile communication system using an automatic retransmission scheme and capable of using at least one of a full rate transition and a limit rate transition. Decoding and checking whether there is a subpacket identifier in the current automatic retransmission channel, checking whether the subpacket identifier is within the maximum number of retransmissions when the subpacket identifier is present, and if it is within the maximum retransmission number as a result of the inspection If the reception failure and the grant message is received through the step of determining the reverse rate using the information of the received grant channel.

Reverse rate, full rate transition, limit rate transition.

Description

Apparatus and method for determining reverse rate in mobile communication system {APPARATUS AND METHOD FOR DETERMINING RATE OF REVERSE LINK IN A MOBILE COMMUNICATION SYSTEM}             

1 is an embodiment of a terminal operation for receiving reverse rate control information proposed by the present invention;

2 is another embodiment of a terminal operation for receiving reverse rate control information proposed by the present invention;

Figure 3 is a block diagram of the main terminal of the present invention is applied.

The present invention relates to an apparatus and a method for determining a transmission rate in a mobile communication system, and more particularly, to an apparatus and a method for determining a reverse transmission rate in a mobile communication system.

In general, the mobile communication system has been developed in the form of a system capable of providing only voice service and simultaneously supporting voice and data, or a system supporting only high speed data. In such a mobile communication system, a transmission rate of a voice service is generally determined according to a standard standard. However, in case of data, the transmission rate may vary continuously according to the amount of data to be transmitted, the channel condition between the base station and the terminal, and the required quality of service (QoS).

In the mobile communication system capable of transmitting data as described above, the direction of data transmission can be largely divided into a forward direction and a reverse direction. Here, the forward direction means the direction from the base station to the terminal, and the reverse direction means the direction from the terminal to the base station. In the mobile communication system, the forward transmission can comprehensively determine all of the resources of the base station, the channel status of the mobile station and the quality of service required by the data to be transmitted by the base station. Therefore, when the mobile communication system controls the forward data rate, the mobile communication system can determine and transmit the base station.

However, in the case of reverse transmission, the base station cannot easily control the transmission rates of all terminals as in the forward transmission. This is because the base station cannot know how much data each terminal will request and how many terminals will request data transmission in the reverse direction. Considering these points, the mobile communication system proposes various methods for determining the reverse rate of the terminal. Hereinafter, the reverse rate determination methods of the terminal proposed by the mobile communication system will be described.

In a typical mobile communication system, data transmission from a terminal to a base station is performed on a physical layer packet (PLP) basis through a packet data channel. The data rate of each physical layer packet is variable every packet, and this is usually controlled by the base station. That is, the base station controls the transmission rate of the various terminals. As described above, the process of determining and controlling the data rate of the terminal by the base station is called scheduling, and the scheduling is performed based on the terminal's feedback on information such as power of the terminal and the amount of data to be transmitted by the terminal.

As such, determining the reverse rate of the terminal is performed by a scheduler of the base station. The scheduler may determine from the 'receive signal-to-noise ratio' of the terminal belonging to the 'Rise of Thermal (Rise of Thermal') (hereinafter referred to as 'RoT') or the current base station (hereinafter referred to as BTS) to determine the reverse rate. Scheduling is performed in consideration of the obtained load. In this way, the scheduler of the base station controls the reverse data rate of the terminal can be classified into two types according to the degree of transition (transition) of the reverse data rate of the terminal. The first method is a full rate transition method, and the second method is a limited rate transition method.

The full rate transition method is a method in which the base station does not limit the transition of the data rate in controlling the reverse data rate of the terminal. On the other hand, the limit rate transition method is a method in which the base station limits the transition of the data rate in one step in controlling the reverse data rate of the terminal. An example of this is as follows.

Possible sets of data rates include 9.6 kbps, 19.2 kbps, 38.4 kbps, 76.8 kbps, 153.6 kbps, 307.2 kbps, and assume that the data rate of the packet data transmitted by the terminal at the specified time is 38.4 kbps. . It is apparent that the number and specific values of the data rates included in the data rate set may vary from system to system. When the full rate transition method is used, the base station determines all data rates in determining the data rate of the next packet for the terminal. That is, it is a system that allows to change the transmission rate of the terminal was transmitted at 9.6 kbps to 307.2kbps at a time. Therefore, the reverse rate of the terminal that the base station can tolerate is not limited to the previous rate of the terminal.

On the other hand, when the limit transition method is used, the base station determines the data rate of the next packet of the terminal to limit the range of one step up or down from the previous packet rate. For example, the rate control of the next packet of the base station for the terminal transmitting at 76.8 kbps is limited to one of 38.4 kbps, 76.8 kbps, 153.6 kbps. In other words, one step up, one step down, or hold at the current rate of 76.8kbps, which is a method of limiting the change in the data rate of the terminal. The one step up, one step down, or maintenance command may be transmitted in the form of 'UP', 'DOWN', 'HOLD', respectively, and signals of '+1', '-1', and '0', respectively. Mapping can be done.

On the other hand, in some systems, as described above, instead of the base station controlling the data rate of the terminal, there is also a system in which the base station controls the TPR of the terminal. The TPR stands for Traffic to Pilot Power Ratio. In a typical mobile communication system, reverse transmission of a terminal is power controlled by a base station. In the power control process, the terminal receives a power control command from the base station to directly control the power of the pilot channel of the terminal, and controls a channel other than the pilot channel with a fixed value of TPR. For example, assuming that the TPR is 3dB, this means that the power ratio of the traffic channel and the pilot channel transmitted by the terminal is 2: 1. Therefore, when the terminal determines the power gain of the traffic channel, the terminal adjusts the power so as to double the pilot channel. In the same principle as for the other types of channels, the gain of the corresponding channel relative to the gain of the pilot channel is controlled with a fixed value. The system for controlling the TPR instead of controlling the transmission rate of the terminal is a system for scheduling each of the reverse transmissions of the various terminals of the base station to control each of them, instead of directly informing the scheduled result at the data rate to each terminal. This is a way of telling the allowed TPR. As the data rate increases, the TPR increases. For example, doubling the data rate means that the power allocated to the traffic channel by the terminal is about twice as large, which means that the TPR is doubled. In a typical mobile communication system, since the terminal and the base station have previously known the relationship between the data rate of the reverse traffic channel and the TPR through the table, the term "substantially controlling the data rate of the terminal" and "controlling the terminal's TPR" are the same. It can be interpreted as meaning. In the following description, for the sake of brevity, only the manner in which the base station controls the data rate of the terminal will be described. However, as described above, even if a specific system takes a method of controlling the TPR instead of controlling the transmission rate of the terminal, it should be noted that the control scheme proposed in the present invention may be applied in the same manner.

The full rate transition method and the limit rate transition method have advantages and disadvantages, respectively. The full rate transition method has the advantage that there is no limitation in determining the data rate of the terminal, while the disadvantage that many bits are required to transmit the scheduling result to the terminal. For example, if there are six data rates as described above, three bits are required to represent all data rates, and since a lot of information needs to be transmitted such as an identifier of each terminal, a large amount of information must be transmitted. will be. In addition, the drawback of the full rate transition method is that as the data rate of a specific terminal changes drastically, the amount of interference affecting another cell is severe, and as a result, the channel change of terminals belonging to other cells is severely changed. This can adversely affect the system. On the other hand, the limit rate transition method has a disadvantage in that the base station is limited to one step change in determining the data rate of the terminal. On the other hand, the limit transition method has an advantage that it is possible to transmit a single bit in transmitting the scheduling result. In other words, the overhead is small. In addition, the limit transition method has an advantage that the change in the amount of interference to other cells is relatively small by limiting the change of the data rate of the UE to one step.

As described above, the base station that performs the scheduling by the full rate transition method or the limit rate transition method controls the transmission rate of the reverse transmission of the terminal by transmitting the scheduling result to the terminal. In general, the full rate transition method transmits the scheduling result to the terminal, for example, 4 bits, which indicates a specific transmission rate to the terminal, and in the limit transition method, the bit rate is increased to the terminal using 1 bit information. Order it. For convenience of explanation, the rate control information transmitted from the base station to the terminal in the full rate transition method is called 'grant', and the rate control information transmitted from the base station to the terminal in the rate transition method is referred to as a 'rate control bit'. (Rate Control Bit). The terminal receives the rate control information, that is, the grant or rate control bits from the base station to continuously control its packet data rate.

If the terminal is performing soft handoff, a situation may occur in which one terminal receives the rate control information from several base stations at the same time. When the soft handoff is performed as described above, the terminal may receive different rate control information from several base stations. For example, one base station can receive information that may transmit 153.6 kbps, and another base station can accept 76.8 kbps. In this situation, if the terminal transmits packet data at a transmission rate of 153.6 kbps, the base station allowing 76.8 kbps causes an excessive load from the terminal than expected by the scheduler, thereby making it difficult to control the load of the base station. Will be. On the other hand, if the terminal transmits the packet data at a transmission rate of 76.8 kbps in the above situation, this may be a safer method than the previous example, but from the point of view of the terminal will get a lower throughput. That is, the base station that allows the 153.6 kbps will not be able to use the reverse load efficiently. This is because, from the standpoint of the base station allowing the 153.6 kbps, it would be better for the terminal to allow only 76.8 kbps and to allow a higher data rate to other terminals.

Therefore, when the terminal performing the soft handoff determines the transmission rate of the terminal according to the transmission rate control information from the various base stations, the method of determining the data transmission rate of the terminal at the highest rate among the transmission rate control information of the various base stations However, since the method of determining the data rate of the terminal at the lowest data rate has its advantages and disadvantages, it cannot be said that any method is necessarily good.

On the other hand, the system designer may determine in advance which one of these two data rate control methods to set, or the base station or the base station controller to perform both methods after the base station or the base station controller described above two methods Either one may be determined and used. As such, when the base station or the base station controller needs to select and use one of two reverse rate determination methods, the base station or the base station controller transmits a message to the terminal through which transmission rate the control method is to be used.

On the other hand, the rate control method described above is applied for each reverse ARQ channel of the terminal. That is, the terminal manages the transmission rate or the TPR value for each ARQ channel, and the base station performs the scheduling by the full rate transition method or the limit rate transition method and transmits the scheduling result, thereby transmitting the transmission rate of the uplink transmission for each ARQ channel of the terminal. To control. For example, in a system using four reverse ARQ channels, an available transmission rate of the first ARQ channel of the UE may be 153.6 kbps and an available transmission rate of the second ARQ channel may be 307.2 kbps. To this end, the base station must transmit rate control information for every ARQ channel in order to continuously control the rate of a specific user equipment, which may cause a large amount of information transmission and degrade performance. To prevent this, the base station may transmit one rate control information and may indicate that the rate information is commonly applied to all ARQ channels. Common rate information applied to all such ARQ channels cannot be directly applied to all ARQ channels at the time when the rate information is received. This is because other base stations can also transmit rate control information for the ARQ channel in the future, and the terminal must determine the rate by combining all of the information. Accordingly, when the common rate control information applied to all ARQ channels is received, the terminal directly applies the common rate control information to the current ARQ channel and applies the same when the ARQ channels are in order for the remaining ARQ channels. Rate control information is stored for each ARQ channel. Then, when it is time to update the rate for the ARQ channel, the terminal determines the available rate by combining the stored common rate control information and the rate control information transmitted at that time.

However, if there is no data to be transmitted to the ARQ channel for the specific ARQ channel, the UE receives a grant or the data rate is updated only when transmission of the data is started and transmission of the data is terminated. . Therefore, the timing at which the data rate is updated in the terminal may be long after the common rate control information for all ARQ channels is transmitted. For this reason, when the base station transmits common rate control information to the terminal, it is necessary to keep track of when the information is applied, and if the reverse situation at the time when the information is actually applied differs from when the previous common rate control information is transmitted. There is a need to transmit new rate control information. This tracking operation makes it difficult to control the transmission rate of the base station, and if the previous information is wrong, a problem may arise in that additional transmission rate control information must be transmitted to correct the information.

Accordingly, an object of the present invention is to provide an apparatus and method for controlling reverse rate by applying common rate control information in a mobile communication system using an ARQ scheme.

Another object of the present invention is to provide an apparatus and method for controlling an effective reverse rate when transmitting packet data in a reverse direction in a mobile communication system using an ARQ scheme.

It is still another object of the present invention to provide an apparatus and method for controlling a reverse rate at the time of transmitting packet data in the reverse direction in a mobile communication system using an ARQ scheme.

A method of the present invention for achieving the above objects is a method for determining the reverse data rate in a mobile communication system that uses an automatic retransmission scheme and can use at least one of a full rate transition and a limit rate transition. Receiving and decoding a grant channel, checking whether a subpacket identifier exists in the current automatic retransmission channel, checking whether the subpacket identifier exists within a maximum number of retransmissions, and within the maximum number of retransmissions as a result of the check In the case of receiving a bad message and a grant message through the response channel includes the step of determining the reverse rate using the information of the received grant channel.

An apparatus of the present invention for achieving the above object is a terminal device for determining the reverse data rate in a mobile communication system that uses an automatic retransmission scheme and can use at least one of a full rate transition and a limit rate transition. A demodulator for demodulating information received through a grant channel, a subpacket ID identifier for identifying a subpacket ID and checking whether the data is currently being transmitted, and for storing the grant information demodulated through the demodulator in a queue And a control unit configured to adjust a reverse rate based on whether data received from the subpacket identifier and grant information corresponding to a current answering channel are received, and grant information queued in the memory.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals have the same reference numerals as much as possible even if displayed on different drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

The present invention proposes a method of improving the timing of applying the common rate control information in order to solve the problem that the timing of applying the common rate control information is delayed as in the prior art. In the present invention, when the terminal is currently transmitting data in the reverse direction, a method of waiting and applying the received common rate control information until a rate update time is used. On the other hand, if the terminal is not currently transmitting data in the reverse direction, a method of immediately applying common rate control information is proposed.

In the operation of transmitting data in the reverse direction, the terminal configures four physical layer subpackets and transmits the data transmitted in one physical layer packet four times. Here, data transmitted in one physical layer packet is not necessarily transmitted four times by configuring four physical layer subpackets, and this example is assumed. In this case, the UE requests the transmission of the second subpacket if the base station does not successfully receive the first subpacket in the transmission of the subpacket. If the second subpacket is not successfully received, the base station performs an operation for requesting retransmission of the third subpacket. Accordingly, when the base station controls the reverse rate for the terminal as described above, the base station may control the rate in units of physical layer packets. That is, the reverse rate can be controlled whenever a physical layer packet transmitted by the terminal is successfully received. Therefore, the base station transmits rate control information such as grant or rate control bit only when the base station successfully receives the reverse packet transmitted by the terminal. Next, the control process for performing such an operation in the terminal will be described.

1 is an embodiment of a terminal operation for receiving reverse rate control information proposed by the present invention. Hereinafter, an embodiment of a terminal operation for receiving reverse rate control information proposed by the present invention will be described with reference to FIG. 1.

In performing the operation of FIG. 1, the terminal performs every reverse frame, and receives reverse rate control information for each ARQ channel and adjusts the rate for each ARQ channel accordingly.

The terminal decodes the grant channel through which the grant, which is the full rate transition control information transmitted from the base station, is transmitted in step 101. As described above, whenever the base station successfully receives one physical layer packet transmitted by the terminal, the base station transmits reverse rate control information. Therefore, the terminal may assume that the reverse transmission is successful. After performing step 101 as described above, the UE checks whether data is being transmitted in the ARQ channel corresponding to the frame previously transmitted in step 102. This can be seen by checking whether the subpacket identifier is null. As described above, as described above, the UE configures four physical layer subpackets and transmits the data transmitted four times, so that when the previously transmitted subpacket identifier is null, the terminal is retransmitting. It means no data.

If there is no data being retransmitted in step 102, the terminal proceeds to step 103; otherwise, the terminal proceeds to step 105. First, the case of proceeding to step 103 will be described. In step 103, the terminal checks whether a grant is received through a grant channel. If the grant is received as a result of the check in step 103, the process proceeds to step 104 to adjust the reverse rate by using the rate control bits received from the grant and various base stations. However, if the grant is not received as a result of the check in step 103, the reverse rate control operation is terminated in the current frame.

On the other hand, if there is data being retransmitted in step 102, that is, if the subpacket identifier is not null, the process proceeds to step 105 and determines whether the transmitted subpacket is the last subpacket. In other words, it checks whether the transmission is performed within the maximum retransmission. Here, the number of retransmissions is within a predetermined number between the terminal and the base station. If the terminal transmits the last subpacket as a result of the check of step 105, since there is no additional subpacket to be transmitted, the terminal proceeds to step 109 to transmit a new packet and updates the reverse rate. However, if the transmission is performed within the maximum retransmission as a result of step 105, the terminal proceeds to step 106 to receive the forward response channel (ACK-CH). Thereafter, the terminal proceeds to step 107 to check whether the response signal received through the forward response channel is a good reception (ACK). If the check result is good, the flow proceeds to step 109 to control the reverse rate. In this case, the grant decoded in step 101 and the rate control bits received from various base stations serve as a reference for determining the reverse rate.

However, if the check result of the reception result (NAK) of step 107 is received, the terminal proceeds to step 108 to check whether the grant has been received. As described above, the rate control is performed for each physical layer packet unit. Therefore, the base station transmits a grant only when one physical layer packet is successfully received. Therefore, when the terminal receives the NAK, if there is a grant received with the terminal, the terminal trusts the grant information more than the NAK information, and determines that the base station has successfully received the reverse packet. Thereafter, the terminal proceeds to step 109 to perform a rate control operation. However, if the grant is not received in step 108, the terminal terminates the reverse rate control operation.

2 is another embodiment of a terminal operation for receiving reverse rate control information proposed by the present invention. Hereinafter, another embodiment of a terminal operation for receiving reverse rate control information proposed by the present invention will be described with reference to FIG. 2.

In step 201, the UE decodes a grant channel through which a grant, which is a full rate transition control information transmitted from a base station, is transmitted. As described above, whenever the base station successfully receives one physical layer packet transmitted by the terminal, the base station transmits reverse rate control information. Therefore, the terminal performs the routine when the transmission of one physical layer packet is successful.

In step 202, the terminal checks whether data is being transmitted in an ARQ channel corresponding to the frame. In this case, the method of determining may use a subpacket identifier (SPID). More specifically, when the SPID is 0, it means initial transmission. When the SPID is one of 1, 2, and 3, it means the first retransmission, the second retransmission, and the third retransmission. As described above, the terminal configures four physical layer subpackets and transmits the data transmitted in one physical layer packet four times. Therefore, if the previously transmitted subpacket identifier is null, that is, the subpacket identifier does not exist. No means that no data is being transmitted. That is, the terminal checks whether the current subpacket identifier is null in step 202. If there is no data being transmitted as a result of the check in step 202, the terminal proceeds to step 203 and determines whether a grant is received through a grant channel corresponding to a current ARQ channel. If a grant is received on the grant channel corresponding to the current ARQ channel as a result of the check in step 203, the process proceeds to step 205 to adjust the reverse rate using the previously received grant and rate control bits received from various base stations. do. However, if the grant corresponding to the current ARQ channel is not received as a result of the check in step 203, the terminal proceeds to step 204 and checks whether the stored common data rate information exists for the current ARQ channel. As a result of the check of step 204, if there is stored grant information, the terminal does not wait until the next transmission rate update and proceeds directly to step 205 to perform the operation of adjusting the transmission rate. In this case, the grant value that is the basis for performing the rate adjustment may be grant information received in the section before the current ARQ channel. On the contrary, if there is no stored grant information as a result of the check in step 204, the reverse rate control operation is terminated in the current frame.

On the other hand, if there is data retransmitted in step 202, the terminal proceeds to step 206 to check whether the transmitted sub-packet is the last sub-packet. The last subpacket is a test for retransmission within the number of retransmissions as described above. If the subpacket identifier is 0, 1, 2, or 3, it is to check whether it is within the third retransmission. If the terminal transmits the last sub packet, since there is no additional sub packet to transmit, the terminal proceeds to step 210 to update the reverse rate in order to transmit a new packet. However, if it is not the last subpacket, that is, the subpacket within the maximum number of retransmissions, the process proceeds to step 207 to receive and decode the response channel to determine whether the transmitted subpacket is successfully received. Thereafter, the terminal proceeds to step 208 to check whether the information transmitted through the response channel is good reception (ACK) or bad reception (NAK). In step 208, if the information received through the response channel is a good reception (ACK), the terminal proceeds to step 210 to perform a reverse rate control operation to be applied to the transmission of a new packet. In this case, the grant decoded in step 201 and the rate control bits received from various base stations serve as a reference for determining the reverse rate.

On the other hand, if the information received on the response channel in step 208 indicates a bad reception (NAK), the terminal proceeds to step 209 to check whether the grant has been received. In general, rate control is performed for each physical layer packet unit. Therefore, the base station transmits a grant only when one physical layer packet is successfully received. Therefore, when the terminal receives a bad reception (NAK), if there is a grant received with the terminal can be determined that the base station successfully received the reverse packet by trusting the grant information more than the bad reception (NAK) information. have. Accordingly, the terminal proceeds to step 210 to perform a rate control operation. However, if the check is not received in step 209, the terminal terminates the reverse rate control operation.

3 is a main block diagram of a terminal to which the present invention is applied. Hereinafter, the main block configuration and operation of each block of the terminal according to the present invention will be described with reference to FIG. 3.

In FIG. 3, components for wireless channel processing of the terminal are not shown. In addition, each block illustrated in FIG. 3 may be configured to be performed by a single processor, that is, a processor or a DSP mounted in a terminal, and may be configured as logic. Here, only the operation of each functional block of the terminal will be examined, and no limitation is imposed on what form the configuration has.

Information received over the wireless channel is demodulated in demodulator 310. The demodulator receives and demodulates not only data but also a signal of a response channel, information of a common rate control channel, and information of a grant channel. The demodulated data is input to the controller 340 or the memory 330 according to the type of data. It should be noted that the data may be input in different blocks at the same time.

The sub packet ID identifier 320 identifies the sub packet ID of data to be transmitted in the reverse direction and outputs it to the controller 340. That is, the present invention determines whether the packet data to be transmitted is a physical layer packet for initial transmission, first retransmission, second retransmission, or third retransmission, and outputs the information to the controller 340. This can be confirmed by checking the subpacket ID value transmitted in the reverse direction. In addition, the memory 330 stores a subpacket and a subpacket ID of a physical layer packet to be transmitted in the reverse direction, and includes a queue for storing grant information received from the demodulator 310.

The rate controller 350 receives and reads the information received from the controller 340 and the above-mentioned information from the subpacket ID identifier 320 and the memory 330, collects them, and determines the reverse rate assigned to the terminal. .

Next, the operation of FIG. 3 will be described in detail with reference to FIG. 2. The demodulator 310 demodulates the information received via the grant channel. The demodulation operation of the grant channel corresponds to operation 201 of FIG. 2. The subpacket identifier 320 checks the identifier of the subpacket currently transmitted on the ARQ channel to check whether there is data being transmitted on the ARQ channel, and outputs the result to the controller 340 and the rate controller 350. The checking of the subpacket identifier corresponds to step 202 of FIG. 2. If there is no data being transmitted through the test result of the subpacket, the controller 340 checks whether the grant information corresponding to the current ARQ channel is received through the memory 330. That is, when the grant information is demodulated by the demodulator 310 and the grant information is received, the grant information corresponding to the current ARQ channel is received in the memory 330. The operation corresponds to step 203 of FIG. 2.                     

If no grant information is received as a result of the check, the controller 340 checks whether there is a grant queued in the memory. That is, it is to check whether there is previous grant information corresponding to the current ARQ channel. The process corresponds to step 204 of FIG.

If there is previous grant information corresponding to the current ARQ channel, the controller 340 controls to output the queued information to the rate controller 350. Through this, the rate controller 350 adjusts the reverse rate using the queued grant. As can be seen from the above description, the controller 340 and the rate controller 350 may be collectively referred to as one controller. In addition, the subpacket identifier 320 may be collectively referred to as a controller.

As described above, in the mobile communication system using the ARQ scheme, the grant information and the common rate control information are applied to control the reverse rate, thereby reducing the time delay.

Claims (4)

A method for determining a reverse data rate in a mobile communication system using an automatic retransmission scheme and capable of using at least one of a full rate transition and a limit rate transition, Receiving and decoding a forward grant channel and checking whether a subpacket identifier exists in an automatic retransmission channel; Checking whether the sub packet identifier exists within a maximum number of retransmissions; And determining a reverse rate by using information on the received grant channel when a reception failure and a grant message are received through a response channel when the number of retransmissions is within the maximum retransmission result. The method of claim 1, Determining that the reverse rate is determined by using the received grant channel information when receiving information on the grant channel when the subpacket identifier does not exist as a result of checking whether the subpacket identifier exists. The method. The method of claim 1 If the subpacket identifier does not exist, if the subpacket identifier does not exist, information is not received through the grant channel, and if there is queued grant information, a process of adjusting the reverse rate using the queued grant information The method characterized in that it further comprises. A terminal apparatus for determining a reverse data rate in a mobile communication system using an automatic retransmission method and using at least one of a full rate transition method and a limit rate transition method, A demodulator for demodulating information received in a grant channel; A subpacket ID identifier for identifying the subpacket ID and checking whether the data is currently being transmitted or not; A memory for storing grant information demodulated through the demodulator in a queue; And a controller configured to adjust a reverse rate based on whether data received from the subpacket identifier and grant information corresponding to a current answering channel are received, and grant information queued in the memory. .

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