KR100987265B1 - Method for controlling data rate of reverse traffic channel in mobile telecommunication system - Google Patents

Abstract

According to the present invention, in order to control the data transmission rate of a reverse traffic channel by a mobile station in a mobile communication system, the i + 3th frame is determined based on the amount of data traffic and transmission power to be transmitted from the i-1th frame to the base station. Determine a data rate for use in a reverse traffic channel, select one of a rate control mode and a schedule mode by comparing the determined rate with a data rate of the i-th frame, and according to the selected mode, Request the use of the determined data rate, and if a response corresponding to the request is received from the base station, control the data rate of the i + 3 frame according to the response, i is a natural number of 2 or more do.

PDCCH, Scheduled Mode, Rate Controlled Mode, Request, Grant, RCB, IAB

Description

Transmission speed control method of reverse traffic channel in mobile communication system {METHOD FOR CONTROLLING DATA RATE OF REVERSE TRAFFIC CHANNEL IN MOBILE TELECOMMUNICATION SYSTEM}             

1 is a view showing the operation of controlling the data transmission rate of the reverse traffic channel in time using the transmission rate control mode according to the present invention.

FIG. 2 is a diagram illustrating an operation of controlling a data transmission rate of a reverse traffic channel using a transmission rate control mode and a schedule mode in accordance with the present invention.

3 is a flowchart illustrating an operation in which a mobile station selects a transmission rate control mode and a schedule mode according to an embodiment of the present invention.

4 is a flowchart illustrating an operation of notifying a mobile station of a reverse data rate by a base station according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating an operation of controlling a reverse data rate in accordance with a rate control mode and a schedule mode in accordance with another embodiment of the present invention. FIG.

6 is a diagram illustrating an operation of controlling a data transmission rate based on a transmission rate control mode and a schedule mode according to another embodiment of the present invention.

7 is a flowchart illustrating an operation in which a mobile station selects a transmission rate control mode and a schedule mode according to the embodiment of FIG.

8 is a flowchart illustrating an operation of notifying a mobile station of a reverse data rate by a base station according to the embodiment of FIG. 6;

The present invention relates to a mobile communication system, and more particularly, to a method of controlling a data transmission rate of a reverse traffic channel transmitted by a terminal.

A typical mobile communication system can be divided into a type of supporting a voice service and a type of data service according to its purpose. A typical example of such a system is a code division multiple access (CDMA) system. Currently, a system that supports only voice services in a CDMA system follows IS (International Standard) -95 and standards based thereon. As communication technology has developed along with user demands, mobile communication systems have been gradually developed to support high-speed data services. For example, the first generation of CDMA 2000 (called CDMA 2000 1x) is designed to support voice services and high-speed data services simultaneously, while 1xEVDO (Evolution in Data Only) is based on the CDMA 2000 1x system. It is designed to support only high speed data service by allocating resource to data service.                         

In a mobile communication system, a transmission generally includes a 'forward' indicating a direction from a base station covering a predetermined area (called a cell) to a mobile terminal capable of moving between cells, and a direction from the mobile terminal to the base station. Are identified by a 'reverse'.

Referring to the transmission of reverse user data in a mobile communication system such as 1xEVDO, user data is transmitted through reverse traffic channel (hereinafter referred to as 'R-TRCH'), 0kbps, 9.6kbps, 19.2kbps, 38.4kbps, It is transmitted at 76.8kbps or 153.6kbps. The base station controls only the maximum possible data rate of the reverse traffic channel, and the mobile terminal selects the data rate to be actually used among the data rates below the maximum possible data rate under the control of the base station. Information for indicating a reverse data rate used by the mobile terminal, that is, a reverse rate indicator (hereinafter referred to as RRI) is referred to as a reverse rate indicator channel (hereinafter referred to as 'R-RICH'). Is reported to the base station.

The method of determining the data rate of the reverse traffic channel in a mobile communication system such as 1xEVDO is as follows. The mobile terminal starts transmission of traffic in the system at 9.6 kbps, the lowest data rate. Thereafter, the reverse data rate is increased by one step only after passing the persistence test. Persistence check refers to a pass when a random number generated within a certain range is small compared to a preset threshold. For example, a mobile terminal transmitting at 9.6kbps can use a higher data rate of 19.2kbps only when it is determined that the persistence test passes.

That is, the base station reduces or increases the reverse data transmission rate by transmitting a reverse activity bit (RAB) to mobile terminals. RAB is one bit of information transmitted every frame and is commonly received by all mobile terminals communicating with one base station. For example, when the RAB transmitted by the base station is '0', all mobile terminals communicating with the base station perform a persistence check, and when passing through this, reduces the data transmission rate of the reverse traffic channel by one step. If the persistence test is not passed, the data rate of the reverse traffic channel is maintained. On the other hand, when the RAB is '1', all mobile terminals communicating with the corresponding base station can increase the data transmission rate through the persistence check, or maintain or decrease it as necessary.

The problem of the method for controlling the reverse data rate can be summarized in two ways. The first problem is that since the base station uses only one bit of RAB to control the data rate, it is impossible to individually control the mobile terminals communicating with the base station. Therefore, the base station cannot increase or decrease the data transmission rate of a specific mobile terminal among mobile terminals in communication. In this case, data transmission speeds actually performed in mobile terminals may not be optimized.

The second problem is that it is very difficult to increase the data rate of the reverse traffic channel to a high data rate. For example, to increase the data rate of 9.6kbps to 153.6kbps in 1xEVDO, four persistence tests must pass. Increasing the data rate makes it difficult to pass the persistence checks, making it virtually impossible to transmit a data rate of 153.6 kbps.

Accordingly, the present invention devised to solve the problems of the prior art operating as described above, provides a method for the mobile terminal to efficiently request the data transmission rate of the reverse traffic channel.

The present invention provides a method for notifying a base station after determining whether to permit a data transmission rate requested by a mobile station.

In the method of controlling the data transmission rate of the reverse traffic channel by the mobile terminal in the mobile communication system according to the present invention, in the method of controlling the data transmission rate of the reverse traffic channel by the mobile terminal in the mobile communication system, i-1 Determining a data transmission rate for use in the reverse traffic channel in an i + 3th frame based on the amount of data traffic and transmission power to be transmitted from the first frame to the base station; Selecting one of a transmission rate control mode and a schedule mode in comparison with a data transmission rate, requesting the base station to use the determined data transmission rate according to the selected mode, and responding to the request from the base station When a response is received, the i + 3 dump according to the response Comprising the step of controlling a random data transmission rate, i is characterized in that two or more natural number.

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In addition, the method for controlling the data transmission rate of the reverse traffic channel by the base station in the mobile communication system according to the present invention, in the method for controlling the data transmission rate of the reverse traffic channel by the base station in the mobile communication system, in the i-th frame Determining whether or not the request information including information on the data transmission rate for use in the reverse traffic channel in the i + 3th frame is normally received from the mobile station; and when the request information is normally received, Determining a maximum data rate available in the i + 3 th frame according to the request information, and transmitting permission information including information on the determined maximum data rate to the mobile terminal; If not normally received, in the i + 3 th frame Determining whether IAB (Increase Availability Bit) information indicating whether to increase the maximum usable data rate is normally received; and if the IAB information is normally received, the i + 3 th according to the IAB information. Determining rate control bit (RCB) information indicating whether to adjust a maximum data rate available in a frame, and transmitting the determined RCB information to the mobile terminal, wherein the determined RCB information includes the reverse traffic. When the data rate for use in the channel is divided into a plurality of stages, RCB information determined to increase the maximum data rate available in the i + 3th frame by one step, in the i + 3th frame RCB determined to indicate that the maximum available data rate will be reduced by one step Information and one of the RCB information determined to indicate that the maximum data rate available in the i + 3 th frame is to be maintained, wherein i is a natural number.

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In addition, the method for controlling the data transmission rate of the reverse traffic channel by the base station in the mobile communication system according to the present invention, in the method for controlling the data transmission rate of the reverse traffic channel by the base station in the mobile communication system, in the i-th frame Receiving, from a mobile station, transmission rate control information indicating a data transmission rate for use in the reverse traffic channel in an i + 3th frame and a mode indicator indicating a type of the transmission rate control information; Determining whether the transmission rate control information is one of request information including data transmission rate information in the i + 3th frame and increase availability bit (IAB) information indicating whether to increase the data transmission rate; If the transmission rate control information is the request information, Determining the maximum usable data rate in the i + 3 th frame according to the information, and transmitting permission information including the determined maximum data rate information to the mobile terminal; And determining the rate control bit (RCB) information indicating whether to adjust the determined maximum data transmission rate according to the IAB information, and transmitting the determined RCB information to the mobile terminal. The RCB information may include the RCB information determined to indicate that the determined maximum data transmission rate is increased by one step when the data transmission rate for use in the reverse traffic channel is divided into a plurality of stages. RCB information determined to indicate a decrease by one step and the maximum determined Determined to indicate that maintain transfer rates comprising either RCB information, it characterized in that the i is a natural number.

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In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

The present invention uses a rate controlled mode to allow the base station to individually control the data rate in the reverse direction. FIG. 1 illustrates an operation of controlling a data transmission rate of a reverse traffic channel in time using a transmission rate control mode according to the present invention.

Referring to FIG. 1, the mobile station transmits control information for the traffic channel along with the traffic channel every frame through a separate control channel. The control channel carries control information related to a hybrid automatic repeat reQuest (hereinafter referred to as HARQ) of a reverse traffic channel. HARQ refers to a technique of retransmitting the same data when a non-acknowledge (NAK) is received for a transmitted data frame and transmitting the next sequence of data when an acknowledgment (ACK) is received.

In addition, the control information includes information related to modulation, encoding, etc. required for receiving a traffic channel transmitted in the same frame, and a request for a data transmission rate to be transmitted after a predetermined time. For example, the mobile station may increase the modulation scheme and coding rate required to receive the traffic channel transmitted in the i-th frame of the control channel and the data rate in the i + 3th frame. 1 bit of IAB (Increase Availability Bit) indicating whether it can be delivered to the base station. The IAB is determined according to the transmission power situation of the mobile terminal and the amount of traffic to be transmitted. That is, the mobile station notifies the base station that its transmission power situation can increase the data transmission rate in the i + 3th frame and increase the transmission rate using the IAB when the amount of traffic to be transmitted is sufficient.

Then, the base station allows one step to decrease, maintain or increase one step the maximum data transmission rate of the mobile station by using a rate control bit (RCB) in consideration of system capacity. The maximum data rate refers to the maximum value of the data rate that the mobile station can transmit in the i + 3th frame.

According to the transmission rate control mode as described above, the base station can individually control the reverse traffic data transmission rate of the mobile terminals communicating with the base station. That is, the mobile stations can notify the base station of the IAB indicating whether the data transmission rate can be increased, and the base station can maximize the system capacity by individually controlling the data transmission rates of the mobile stations according to the IAB.

However, in the rate control mode, the time required for using the high data rate is still long. In other words, the mobile terminal transmitting at 9.6kbps requires a process of 9.6kbps → 19.2kbps → 19.2kbps → 38.4kbps → 38.4kbps → 76.8kbps, 76.8kbps → 153.6kbps in order to transmit at 153.6kbps. The mobile terminal must exchange RCBs with multiple IABs.

In general, when one mobile terminal uses a high data rate, most of the system capacity of the base station is allocated. Therefore, a shorter time interval during which a specific mobile station uses the high data rate is preferable in view of system throughput. However, if the data rate is reduced from 153.6kbps to 9.6kbps, the transmission rate control mode must be processed from 153.6kbps → 76.8kbps, 76.8kbps → 38.4kbps, 38.4kbps → 19.2kbps, 19.2kbps → 9.6kbps. Because it takes a lot of time as well.

Therefore, the present invention facilitates the use of a high data rate by using a schedule mode in addition to the rate control mode.

FIG. 2 illustrates an operation of controlling a data transmission rate of a reverse traffic channel using a transmission rate control mode and a schedule mode in accordance with the present invention. Herein, the mobile station controls the reverse rate according to the rate control mode or the schedule mode every frame.

Referring to FIG. 2, in the i th frame, the mobile station transmits control information through the first reverse control channel together with the traffic channel according to the transmission rate control mode. Here, the first reverse control channel is shown as a reverse packet data control channel (R-PDCCH). The control information includes information related to modulation, encoding, and the like of a traffic channel transmitted in the same frame, and a 1-bit IAB indicating whether the data transmission rate can be increased after a predetermined time interval.

The control information transmitted in the i-th frame includes information related to modulation, encoding, etc. required to receive a traffic channel transmitted in the i-th frame, and an IAB indicating whether the data transmission rate can be increased in the i + 3 th frame. do. The IAB is used by the base station to control the maximum data transmission rate of the mobile station, and the control result is notified to the mobile station through a silo transmission control channel to the RCB transmitted by the base station. The RCB is information that allows the mobile station to decrease, maintain or increase the maximum value of the data rate that can be transmitted in the i + 3th frame by one step, which is the transmission rate control mode in FIG. Is the same as

In the i + 1th frame, the mobile station requests a specific data rate from the base station through the second reverse control channel according to the schedule mode. The base station transmits grant information indicating a maximum data transmission rate allocated to the mobile station through the forward control channel in response to the request. The permission information specifically designates a new maximum data rate regardless of the current maximum data rate of the mobile terminal. Therefore, unlike the transmission rate control mode, the schedule mode can increase the reverse data rate by one step at a time.

In order to control the data transmission rate using the schedule mode, additional information is required. The information transmitted by the mobile station to the base station for the schedule mode is referred to as request information as including the desired data rate, the amount of traffic remaining in the buffer of the mobile station, the transmission power of the mobile station, and the type of traffic. The request information is transmitted to the base station using the second reverse control channel. The second reverse control channel does not need to be transmitted when using the transmission rate control mode and is an additional control channel that is selectively used only when using the schedule mode.

When the mobile station transmits the request information related to the schedule mode in the i + 1th frame, the base station checks the requested data transmission rate according to the request information and indicates information indicating whether or not to allow it (hereinafter referred to as permission information). It is delivered to the mobile terminal through the forward control channel. The permission information is for notifying the mobile terminal which has transmitted the request information the maximum value of the available data transmission rate. The mobile station receiving the grant information transmits a data frame below the maximum data rate of the reverse traffic channel allowed by the base station in the i + 4th frame.

Whether a data transmission rate is requested using a schedule mode or a data transmission rate using a transmission rate control mode for each frame is determined by the data transmission rate requested by the mobile terminal. There are two ways for the mobile terminal to determine this.

According to the first determination method, when the data rate to be transmitted in the i + 3th frame is a high data rate exceeding a predetermined criterion, the mobile station requests a desired data rate according to the schedule mode. On the other hand, if the data rate to be transmitted in the i + 3th frame does not exceed a certain criterion, the mobile station requests the desired data rate according to the rate control mode.

For example, in a mobile communication system supporting transmission speeds of 9.6kbps to 1.024Mbps, the mobile terminal uses a transmission rate control mode when requesting a data rate of less than 76.8kbps and a schedule mode when requesting a data rate of 76.8kbps or more. Use The reference data transmission rate may be separately set for each mobile terminal according to priority and radio channel environment.

According to the second determination method, if the data transmission rate transmitted in the i + 3th frame is two or more steps larger than the data transmission rate in the ith frame, the mobile station requests the desired data transmission rate according to the schedule mode. do. On the other hand, if the data transfer rate is one step higher or if there is no need to increase the data rate, the desired data rate is requested using the rate control mode. As such, the second decision method selects one of the transmission rate control mode and the schedule mode according to the relative increase in the desired data rate.

3 is a flowchart illustrating an operation in which a mobile station selects a transmission rate control mode and a schedule mode according to an embodiment of the present invention.

Referring to FIG. 3, in step 310, the mobile station determines the data transmission rate of the reverse traffic channel after a predetermined time period in consideration of the amount of traffic remaining in its buffer and transmittable power. The detailed description of the determination of the data transmission rate will be omitted since it departs from the gist of the present invention. The determined data rate is the data rate to be used in the traffic channel to be transmitted after four frames. That is, the mobile station makes a decision on the data rate that can be transmitted in the i + 3 th frame in the i-1 th frame. Herein, the four frames are determined in consideration of the propagation delay and the processing delay between the mobile station and the base station.

In step 320, the mobile station determines which method of transmission rate control mode and schedule mode to use according to the determined data rate. Specifically, the mobile station selects a transmission speed control mode or a schedule mode according to a predetermined reference data transmission rate or a relative increase in the determined data transmission rate by one of the above two determination methods.

If it is determined that the transmission rate control mode is used, in step 330, the mobile station transmits an IAB indicating that uplink data rate can be adjusted to the base station through the first reverse control channel of the i-th frame. The IAB is included in control information transmitted through the first reverse control channel.

On the other hand, if it is determined that the schedule mode is used, the mobile station transmits request information including the determined data rate to the base station directly through the second reverse control channel of the i-th frame in step 340 to directly request a desired data rate. At the same time, the IAB is transmitted to the base station through the first reverse control channel indicating that the data transmission rate can be adjusted upward. This is to allow the base station to control the reverse data transmission rate even when the base station does not receive the request information normally.

In general, a cyclic redundancy code (CRC) is added to the control channel so as to check whether there is an error, and the base station can know whether an error has occurred through the CRC check. Therefore, when an error occurs in the second reverse control channel, the base station does not use the request information, but instead controls the data transmission rate of the mobile station based on the IAB received through the first reverse control channel.

4 is a flowchart illustrating an operation of notifying a mobile station of a reverse data rate by a base station according to an embodiment of the present invention.

Referring to FIG. 4, the base station receives the first reverse control channel signal and the second reverse control channel signal in step 410, and determines whether there is an error in the reception result of the second reverse control channel in step 420. Whether there is an error is made by performing a CRC check on the information obtained by decoding the signal of the second reverse control channel.

When the second reverse control channel is normally received, the base station determines that the mobile station requests the desired data transmission rate according to the schedule mode. Therefore, in step 430, the base station determines the maximum data transmission rate to be used by the mobile terminal after three frames in consideration of the request information and system capacity received through the second reverse control channel. That is, in the i-th frame, the base station determines the maximum data rate for the mobile station to use in the i + 3 th frame.

In step 440, the base station determines whether the determined maximum data rate is two or more steps greater than the data rate transmitted by the mobile station in the i-th frame. If large, in step 450, the base station transmits the grant information directly including the determined maximum data rate to the mobile station using the forward control channel. In addition, in step 450, the base station transmits an RCB, which means to adjust the maximum reverse data rate up by one step, through a separate rate control channel. As described above, when the grant information and the RCB are simultaneously transmitted, when the mobile terminal fails to receive the grant information normally due to an error in the forward control channel, the mobile station may adjust the maximum data rate by at least one step by using the RCB. To make it work.

The maximum data rate refers to the maximum data rate that the mobile station is allowed to transmit to the base station in a particular frame. That is, when the base station notifies the maximum data transmission rate of 153.6kbp, the mobile station may select and transmit as needed from among data transmission rates of 0kbps to 153.6kbps.

If it is determined in step 440 that the determined maximum data rate is greater than or equal to one step than the data rate transmitted by the mobile station in the i-th frame, in step 460 the base station uses only the RCB without using the forward control channel. It informs the mobile station to adjust, maintain or down- regulate the maximum data rate by one step.

Even when the request information is received from the mobile terminal as described above, the base station transmits the grant information only when the maximum data transmission rate of the mobile terminal is increased by two or more steps. Otherwise, the base station transmits the RCB. This is to minimize the transmission frequency of the grant information as much as possible to minimize the reduction of the forward system capacity due to the forward control channel.

On the other hand, if it is determined in step 420 that the second reverse control channel is not normally received, the base station recognizes that the mobile station has requested a desired data transmission rate according to the transmission rate control mode. Therefore, in step 470, the base station adjusts, maintains, or decreases the maximum data rate to be transmitted by the mobile station one step after a predetermined time period in consideration of the IAB and system capacity received through the first reverse control channel. Decide if you want to adjust. In step 480, the base station transmits the determination result to the RCB to the mobile station through the forward control channel.

The operation of the base station as described above is performed for each of the plurality of mobile terminals communicating with the base station. The base station controls the maximum data transmission rate of each mobile terminal according to the transmission power of each mobile terminal, the priority of each terminal, and the priority according to the type of data traffic. That is, the base station determines the maximum data transmission rate of a specific mobile station relatively large and sets the maximum data transmission rate of other mobile terminals relatively small, or sets only the maximum data transmission rate of a specific mobile terminal relatively large and Data transmission can be suppressed by setting the maximum data rate to zero.

In the above, the operation according to the embodiment in which the mobile terminal requests the reverse data rate in each frame by the rate control mode, the schedule mode, or the mixed mode has been described. According to another embodiment of the present invention, instead of using a plurality of control channels, the mobile terminal simultaneously transmits control information and request information using a common control channel.

FIG. 5 illustrates an operation of controlling the reverse data rate by a transmission rate control mode and a schedule mode in accordance with another embodiment of the present invention.

Referring to FIG. 5, the mobile station transmits the IAB to the base station through the first reverse control channel with whether the uplink data rate can be adjusted upward according to the transmission rate control mode. As described above, the first reverse control channel transmits traffic control information related to modulation and encoding necessary for receiving a traffic channel transmitted in a corresponding frame and control information including the IAB.

On the other hand, when requesting the upregulation of the data transmission rate according to the schedule mode, the mobile terminal transmits the traffic control information and the request information together through the second reverse control channel. The request information directly specifies a data transmission rate requested by the mobile terminal. That is, in this embodiment, the request information includes the data transmission rate desired by the mobile station, the amount of traffic remaining in the buffer of the mobile station, the transmission power of the mobile station, the type of traffic, and the like, and the traffic control information includes the traffic transmitted in the corresponding frame. Modulation, encoding, etc. required to receive the channel.

Similarly, the mobile station uses either the first reverse control channel or the second reverse control channel depending on whether to use the transmission rate control mode or the schedule mode. Then, the base station receives both signals of the first and second reverse control channels and performs a CRC check to determine which control channel is used by the mobile station, that is, how to control the data rate in a transmission rate control mode or a schedule mode. You can see if it is requested.

As shown in FIG. 5, since only one of the first reverse control channel and the second reverse control channel is transmitted in the same frame, when the base station performs the CRC check, the second reverse control channel passes when the first reverse control channel passes. The channel will not pass and conversely if the second reverse control channel passes, the first reverse control channel will not pass.

The operation of the base station for determining the reverse data transmission rate using the control information received through the first reverse control channel or the request information received through the second reverse control channel is as described above. That is, the base station operates in steps 470 and 480 when receiving control information, and in steps 430 through 460 when it receives traffic control information and request information.

FIG. 6 illustrates an operation of controlling a data transmission rate in time according to a transmission rate control mode and a schedule mode according to another embodiment of the present invention. Herein, the mobile station controls the reverse rate according to the rate control mode or the schedule mode every frame.

According to FIG. 6, the mobile station transmits only one reverse control channel at any time, regardless of the reverse data rate according to the transmission rate control mode or the reverse data rate according to the schedule mode. However, the mobile station transmits the control information or the request information through the reverse control channel according to which of the transmission rate control mode and the schedule mode request adjustment of the data rate.

When requesting adjustment of the data transmission rate according to the transmission rate control mode, the mobile station indicates traffic control information related to modulation and encoding necessary to receive the traffic channel transmitted in the corresponding frame, and indicates whether the maximum data transmission rate can be adjusted. Control information including the IAB is transmitted on the reverse control channel. On the other hand, when requesting the adjustment of the data transmission rate according to the schedule mode, the mobile station transmits the request information indicating the desired data transmission rate to the reverse control channel.

At this time, the mobile station transmits a schedule mode indicator together so that the base station can distinguish whether the reverse control channel carries control information for transmission rate control mode or request information for schedule mode in a specific frame period. The schedule mode indicator is transmitted with the control information or the request information, has a value of '0' when transmitted with the control information, and has a value of '1' when transmitted with the request information.

In FIG. 6, when a mobile station requests up-regulation of a data transmission rate in a scheduled mode, traffic control information related to modulation and encoding necessary for receiving a reverse traffic channel transmitted in the same time period is included in the request information transmitted in the corresponding frame. not included. That is, if the 'schedule mode indicator' is '1' in the i + 1th frame, the request information transmitted in the corresponding section includes only information on the data transmission rate requested by the mobile station in the i + 4th frame. Traffic control information or IAB for receiving the traffic channel transmitted in the +1 th frame is not included.

Therefore, the mobile station uses the same modulation and coding as the previous frame and uses the same data rate in the traffic channel transmitted in the frame having the 'schedule mode indicator' '1'. If the 'schedule mode indicator' is '1' in the i + 1th frame, the request information transmitted in the corresponding interval includes only the data transmission rate requested by the mobile station in the i + 4th frame, but not in the i + 1th frame. It does not include information for receiving the transmitted traffic channel. Instead, the traffic channel transmitted in the i + 1th frame uses the same modulation, encoding, and data rate as the ith frame. Therefore, when a 'schedule mode indicator' is '1' in a frame, the base station receives the traffic channel of the i + 1 th frame using the control information received in the previous frame.

FIG. 7 is a flowchart illustrating an operation in which a mobile station selects a transmission rate control mode and a schedule mode according to the embodiment of FIG. 6.

Referring to FIG. 7, in step 710, the mobile station determines a data transmission rate of a traffic channel after a predetermined time period in consideration of the amount of traffic remaining in its buffer and transmittable power. The data rate determined at this time is the data rate to be used in the traffic channel to be transmitted after 4 frames. That is, the mobile station determines the data rate that can be transmitted in the i + 3th frame in the i-1th frame.

In step 720, the mobile station determines whether to use the transmission rate control mode or the schedule mode according to the determined data transmission rate. Specifically, the mobile station selects a transmission rate control mode or a schedule mode according to a predetermined reference data rate or a relative increase in the determined data rate by one of the two determination methods mentioned above.

If it is determined that the transmission rate control mode is used, in step 730, the mobile station schedules control information including an IAB that informs the base station that the uplink data rate can be adjusted to the base station through the reverse control channel of the i-th frame. Send with mode indicator. The control information further includes traffic control information related to modulation and encoding necessary for the base station to receive the traffic channel transmitted together in the corresponding frame.

On the other hand, if it is determined that the schedule mode is used, the mobile station transmits request information including the determined data rate to the base station with the schedule mode indicator set to '1' to the base station through the reverse control channel of the i-th frame in step 740.

8 is a flowchart illustrating an operation of notifying a mobile station of a reverse data rate by a base station according to the embodiment of FIG. 6.

Referring to FIG. 8, the mobile station receives the reverse control channel in step 810 and determines whether a value of the schedule mode indicator received through the reverse control channel is '0' or '1'. If the value of the schedule mode indicator is '1', in step 830, the base station considers the system capacity and the data transmission rate included in the request information received through the reverse control channel, and the like to be used by the mobile station after a predetermined time interval. Determine the data rate. That is, in the i-th frame, the base station determines the maximum data rate for the mobile station to use for the i + 3 th frame.

In step 840, the base station determines whether the determined maximum data rate is two or more steps greater than the data rate transmitted by the mobile station in the i-th frame. If large, in step 850, the base station transmits the grant information directly specifying the determined maximum data rate to the mobile station using the forward control channel. In addition, in step 850, the base station transmits an RCB, which means to adjust the maximum reverse data rate by one step, through a separate transmission rate control channel. As described above, when the grant information and the RCB are simultaneously transmitted, when the mobile terminal fails to receive the grant information normally due to an error in the forward control channel, the mobile station may adjust the maximum data rate by at least one step by using the RCB. To make it work.                     

If the determined maximum data rate is greater than or equal to one step than the data rate transmitted by the mobile station in the i-th frame in step 840, the base station moves using only the RCB without using the forward control channel in step 860. Notify the terminal to adjust, maintain or down-regulate the maximum data rate by one step.

On the other hand, if it is determined in step 820 that the value of the schedule mode indicator is '0', the base station recognizes that the mobile station requests the data transmission rate according to the transmission rate control mode. Therefore, in step 870, the base station determines whether to adjust the maximum transmission rate to be used by the mobile station one step up, one step down or one step down in consideration of system capacity and control information received through the reverse control channel. Decide In step 880, the base station transmits the determination result to the RCB to the mobile station through the forward control channel.

In FIG. 4 and FIG. 8, when the base station transmits the grant information to the mobile stations requesting the uplink data rate adjustment in the schedule mode, the base station additionally transmits an RCB meaning to upstream the data rate. The reason for transmitting the RCB in this way is to prepare for the case that the mobile station does not normally receive the authorization information. The mobile station performs a CRC check on the forward control channel and, if it passes, adjusts the maximum data transmission rate by using the permission information received through the forward control channel. Adjust the baud rate by one step.                     

Similarly, the base station individually controls the maximum data transmission rate of each mobile terminal according to transmission power, priority of each terminal, priority of each traffic type, etc. of the plurality of mobile terminals in communication.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. In the above description, embodiments in which the mobile terminal requests adjustment of the data transmission rate and notify the base station how to adjust the data transmission rate have been described. However, according to a modified embodiment of the present invention, the traffic is used instead of the data transmission rate of the traffic channel. The data rate of the reverse traffic channel is controlled by using the power ratio to the pilot signal of the channel. The power ratio to the pilot signal of the traffic channel is a value obtained by dividing the power of the traffic channel transmitted by the mobile station by the power of the reverse pilot signal. In general, since the data rate is proportional to the power ratio to the pilot signal of the traffic channel, the base station can optimize the system capacity even if the mobile station uses the power ratio to the pilot signal of the traffic channel to be transmitted. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

The effect obtained by the present invention operating as described in detail above is briefly described as follows.

The present invention can efficiently control the data transmission speed of the reverse traffic channel transmitted by the mobile station while optimizing the system capacity and minimizing the burden on the transmission of the radio section.

Claims (14)

A method for controlling the data transmission rate of a reverse traffic channel by a mobile terminal in a mobile communication system, determining a data transmission rate for use in the reverse traffic channel in the i + 3th frame based on the amount of data traffic and the transmission power to be transmitted to the base station in the i-1th frame; Selecting one of a transmission rate control mode and a schedule mode by comparing the determined data rate with the data rate of the i-th frame; Requesting the base station to use the determined data rate according to the selected mode; If a response corresponding to the request is received from the base station, controlling the data transmission rate of the i + 3 th frame according to the response; i is a natural number of 2 or more. The method of claim 1, The process of selecting one of the transmission rate control mode and the schedule mode, Selecting the schedule mode if the determined data transmission rate is greater than or equal to the reference transmission rate; and selecting the transmission rate control mode if the determined data transmission rate is less than the reference transmission rate. . The method of claim 1, The process of selecting one of the transmission rate control mode and the schedule mode, When the data rate for use in the reverse traffic channel is divided into a plurality of stages, the schedule mode is selected when the determined data rate is two or more steps greater than the data rate in the i-th frame, and the determined And selecting the transmission rate control mode when the data transmission rate is not greater than two levels greater than the data transmission rate in the i-th frame. The method of claim 1, The process of requesting the use of the determined data rate may include: When the transmission rate control mode is selected, the IAB (Increase Availability Bit) information indicating whether the determined data transmission rate is greater than the data transmission rate in the i-th frame and the traffic control information for the reverse traffic channel are read. transmitting to the base station through a first reverse control channel of an i-th frame. The method of claim 4, wherein The process of requesting the use of the determined data rate may include: When the schedule mode is selected, the request information including information on the determined data transmission rate is transmitted to the base station through the second reverse control channel of the i-th frame, and is transmitted to the IAB information and the reverse traffic channel. And transmitting the traffic control information for the base station through the first reverse control channel of the i-th frame. The method of claim 4, wherein The process of requesting the use of the determined data rate may include: When the schedule mode is selected, transmitting request information including information on the determined data transmission rate and traffic control information for the traffic channel to the base station through a second reverse control channel of the i-th frame. Data rate control method comprising. The method of claim 1, The process of requesting the use of the determined data rate may include: If the transmission rate control mode is selected, IAB (Increase Availability Bit) information indicating whether the determined data rate is greater than the data rate of the i-th frame, traffic control information for the reverse traffic channel, and Transmitting a mode indicator indicating a transmission rate control mode to the base station through the reverse control channel of the i-th frame; When the schedule mode is selected, data comprising request information including information on the determined data transmission rate and a mode indicator indicating the schedule mode to the base station through the reverse control channel of the i-th frame. Transmission speed control method. The method according to any one of claims 4 to 7, The request information, And the information on the determined data transmission rate, the amount of data traffic to be transmitted to the base station, the transmission power, and the type of traffic. The method according to any one of claims 4 to 7, Traffic control information for the reverse traffic channel, And a modulation scheme and code rate information used in the reverse traffic channel in the i-th frame. The method of claim 1, The process of controlling the data transmission rate, Determining whether permission information including information about a maximum data transmission rate has been received from the base station; When the permission information is received, determining a data transmission rate for use in the reverse traffic channel in the i + 3th frame within a range below the maximum data transmission rate; Determining whether or not the rate control bit (RCB) information indicating whether to adjust the maximum data transmission rate is received from the base station when the permission information is not received; If the RCB information is received, adjusting the maximum data transmission rate according to the RCB information, and determining the data transmission rate in the i + 3 th frame within a range below the adjusted maximum data rate. , The RCB information, When the data rate for use in the reverse traffic channel is divided into a plurality of stages, the RCB information determined to indicate that the maximum data rate is increased by one step, and the maximum data rate is decreased by one step. And one of the RCB information determined to indicate and the RCB information determined to indicate maintaining the maximum data rate. A method of controlling a data transmission rate of a reverse traffic channel by a base station in a mobile communication system, determining whether the request information including information on the data transmission rate for use in the reverse traffic channel in the i + 3th frame is normally received from the mobile station in the i th frame; When the request information is normally received, the maximum data rate available in the i + 3th frame is determined according to the request information, and the permission information including information on the determined maximum data rate is transmitted to the mobile terminal. Transfer process, When the request information is not normally received, determining whether or not IAB (Increase Availability Bit) information indicating whether to increase the maximum data transmission rate available in the i + 3th frame is normally received; If the IAB information is normally received, determine the Rate Control Bit (RCB) information indicating whether to adjust the maximum data rate available in the i + 3th frame according to the IAB information, and the determined RCB information Including the process of transmitting to the mobile terminal, The determined RCB information is, When the data rate for use in the reverse traffic channel is divided into a plurality of stages, the RCB information determined to indicate that the maximum data rate available in the i + 3th frame is increased by one step, i + 3 One of RCB information determined to indicate reducing the maximum data rate available in the first frame by one step and RCB information determined to indicate maintaining the maximum data rate available in the i + 3th frame, I is a natural number, characterized in that the data rate control method. The method of claim 11, The process of transmitting the permission information to the mobile terminal, If the determined maximum data transmission rate is two or more steps greater than the data transmission rate of the i-th frame, transmitting the RCB information determined to indicate that the grant information and the determined maximum data transmission rate are increased by one step. Process, And transmitting the RCB information indicating whether to adjust the determined maximum data transmission rate when the determined maximum data transmission rate is not more than two steps greater than the data transmission rate of the i-th frame. RCB information indicating whether to adjust the determined maximum data transmission rate, RCB information determined to indicate increasing the determined maximum data rate by one step, RCB information determined to indicate reducing the determined maximum data rate by one step, and determined to indicate maintaining the determined maximum data rate. Data rate control method comprising one of the RCB information. A method of controlling a data transmission rate of a reverse traffic channel by a base station in a mobile communication system, receiving transmission rate control information indicating a data transmission rate for the reverse traffic channel in an i + 3th frame and a mode indicator indicating a type of the transmission rate control information from a mobile station in an i-th frame; According to the mode indicator, whether the rate control information is one of request information including data rate information in the i + 3th frame and IAB (Increase Availability Bit) information indicating whether to increase the data rate. Judging the process, If the transmission rate control information is the request information, the maximum available data transmission rate in the i + 3th frame is determined according to the request information, and the permission information including the determined maximum data transmission rate information is included in the mobile terminal. Transfer to, If the transmission rate control information is the IAB information, determine Rate Control Bit (RCB) information indicating whether to adjust the determined maximum data transmission rate according to the IAB information, and transmit the determined RCB information to the mobile terminal. Process, The determined RCB information is, When the data rate for use in the reverse traffic channel is divided into a plurality of stages, the determined maximum data rate is determined by one stage, and the determined maximum data rate is reduced by one stage. One of the RCB information determined to indicate that the message and the RCB information determined to indicate to maintain the determined maximum data transmission rate, I is a natural number, the method for controlling the data rate of the reverse traffic channel by the base station in a mobile communication system. The method of claim 13, The process of transmitting the permission information, If the determined maximum data rate is greater than or equal to two steps than the data rate of the i-th frame, transmitting the RCB information and the permission information to increase the determined maximum data rate by one step; , If the determined maximum data rate is not more than two steps greater than the data rate of the i-th frame, transmitting the RCB information indicating whether to adjust the determined maximum data rate to the mobile terminal; Control method.

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