KR20030046272A - Apparatus and method for controlling data rate of reverse channel in mobile communication system - Google Patents

Abstract

PURPOSE: A method for controlling a transmission rate of a reverse channel in a mobile communication system is provided to determine a transmission rate of an R-CQICH(Reverse Channel Quality Indicator Channel) in a forward transmission end, and to control the transmission rate by transmitting the determined rate, thereby freely controlling the transmission rate of the R-CQICH. CONSTITUTION: A base station obtains information on power assigned to a packet data service(200). The base station obtains information on the number of Walsh codes assigned to the packet data service(202). The base station obtains information on interferences of an R-CQICH received from a terminal(204). The base station obtains information on a kind of the packet data service of the terminal(206). The base station obtains information on the number of entire terminals(208). The base station determines a transmission rate of the R-CQICH by using the obtained information, and transmits the determined transmission rate to the terminals(210).

Description

Apparatus and method for controlling the rate of reverse channel in mobile communication system {APPARATUS AND METHOD FOR CONTROLLING DATA RATE OF REVERSE CHANNEL IN MOBILE COMMUNICATION SYSTEM}

The present invention relates to a mobile communication system, and more particularly, to an apparatus and method for controlling a transmission rate of a reverse channel (R-CQICH) for transmitting forward channel status information.

With the rapid development of mobile communication system technology, mobile communication service is developing from the conventional voice service, which used only voice, to the data service for video communication and the Internet. Is in. In order to efficiently transmit the service, the mobile communication service separates a circuit channel for a voice service and a packet data channel for a data service.

For example, in a system that supports both a circuit channel and a packet data channel such as 1xEV-DV, the terminal may request a packet data service by maximizing the data transmission capability of the base station by utilizing a given base station resource for the packet data service. We want to increase the data rate. To this end, the base station determines and transmits a data rate according to the channel status of the terminal when scheduling a terminal to transmit packet data. Therefore, the packet data service requires the terminal to transmit this information in order to use the forward channel state information of the terminal. By transmitting the forward channel state information of the terminal in the reverse direction, even if some interference (interference) to the reverse data transmission to perform the forward data transmission effectively. This information is transmitted through Reverse R-CQICH (Reverse Channel Quality Indicator CHannel), which considers transmitting this information in units of 800 Hz.

However, in a system supporting circuit users and packet users at the same time, the base station preferentially allocates base station resources, that is, base station power and Walsh codes, for the circuit users and other base station power and Walsh codes for packet data users. As the number of circuit users increases or decreases, the base station power for supporting the circuit users changes, and the base station resources allocated for the packet data users also change. Regardless of whether the base station resource for the packet data user is large or small, uniformly transmitting the reverse R-CQICH at a constant transmission rate is very inefficient, so a technique for changing the transmission rate of the reverse R-CQICH is required.

Accordingly, an object of the present invention is to provide an apparatus and method for controlling a transmission rate of a reverse channel (R-CQICH) for transmitting forward channel status information in a mobile communication system.

In the mobile communication system supporting both the high speed data service and the voice service to achieve the above objects, the base station determines and transmits a transmission rate of a reverse channel quality indication channel (R-CQICH) for transmitting forward channel state information. The method for determining the transmission rate of the reverse channel quality indication channel based on the amount of power available for packet service and the measured interference amount of the reverse channel quality indication channel, and the transmission rate of the determined reverse channel quality indication channel to the terminal It characterized in that it comprises a process of transmitting.

1 is a diagram illustrating signals exchanged between a terminal and a base station to control a transmission rate of an R-CQICH for transmitting forward channel state information in a mobile communication system according to an exemplary embodiment of the present invention.

2 is a diagram illustrating a procedure of a base station for determining a reverse R-CQICH transmission rate according to an embodiment of the present invention.

3 is a diagram illustrating a procedure for determining an R-CQICH transmission rate by using a power amount of a base station and an interference amount of a reverse channel R-CQICH according to an embodiment of the present invention.

4 is a diagram illustrating a procedure for receiving reverse channel R-CQICH rate information from a terminal, which is a forward receiving end according to an embodiment of the present invention, and controlling the rate of reverse channel R-CQICH using this information.

5 illustrates an apparatus of a mobile station for controlling and transmitting a transmission rate of an R-CQICH according to an embodiment of the present invention.

FIG. 6A shows channel gain (Gn) when the R-CQICH data rate is 800 Hz. FIG.

FIG. 6B is a diagram illustrating channel gain when the R-CQICH data rate is 400 Hz. FIG.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, the present invention will be described a technique for controlling the transmission rate of the R-CQICH transmitting the forward channel state. Here, the considerations for controlling the transmission rate of the R-CQICH, the amount of base station power and Walsh code available for the packet data service, the amount of reverse channel R-CQICH interference measured by the base station, the type of packet data service of the terminal and the total terminal Number and so on.

On the other hand, the rate information of the R-CQICH determined in consideration of the various factors as described above is transmitted to the terminal, the terminal resets the period for transmitting the forward channel state information based on the rate information received from the base station. That is, the terminal transmits the R-CQICH to the base station at the reset period.

1 illustrates signals exchanged between a terminal and a base station to control a transmission rate of an R-CQICH for transmitting forward channel state information in a mobile communication system according to an exemplary embodiment of the present invention.

As shown, the UE transmits the R-CQICH at the transmission rate of the R-CQICH currently set in step 100. Here, the R-CQICH includes forward channel state information as described above. The base station receiving the R-CQICH from the terminal determines the transmission rate of the R-CQICH after the method described in FIG. The base station transmits the determined rate of the R-CQICH to the terminal in step 102. The terminal receiving the transmission rate of the R-CQICH has an R-CQICH transmission rate received from the base station in step 104 and then performs the method described in FIG. 3 to change the transmission period of the R-CQICH, and to change the changed transmission rate. Apply to transmit the R-CQICH.

2 illustrates a procedure of a base station for determining a reverse R-CQICH transmission rate according to an embodiment of the present invention.

Factors to be considered for the base station to determine the transmission rate of the R-CQICH transmitting the forward channel status information include the amount of power information allocated to the packet data service at the base station, the number of Walsh codes allocated to the packet data service, and the R-CQICH. Measurement of the amount of interference, the type of packet data service of the terminal, and the total number of terminals. Such information can be used to determine the degree of utilization of the base station resources for packet data service and the degree of interference of the R-C1QICH on the reverse channel. By using this information, the base station determines the appropriate transmission rate of the R-CQICH.

Referring to FIG. 2, first, the base station acquires information on the amount of power allocated to the packet data service in step 200. This information is most closely related to the packet data rate of the base station. If the amount of base station power is high, the packet data rate is high, and if the amount of base station power is low, the packet data rate is low. The amount of power allocated to the packet data service is the amount of power excluding the amount of power allocated to the circuit user among the total amount of power of the base station. In step 202, the base station acquires information on the number of Walsh codes allocated to the packet data service. This information can be obtained by subtracting the total number of Walsh codes supported by the base station from the number of Walsh codes supported for the circuit users. The base station acquires information on the amount of interference of the R-CQICH received from the terminal in step 204. This information sets the sum of the measurements of the interference amount of the R-CQICH received from each terminal as the ratio of the ratio to the base station thermal noise. In step 206, the base station acquires information on a packet data service type of the terminal. Information about whether the packet data service is a "ftp" service irrespective of time delay or a "Near real-time" service related to time delay is obtained. In step 208, the base station acquires information on the total number of terminals. This is because the greater the number of terminals, the greater the amount of interference on the reverse channel, and the smaller the amount of interference, the less the amount of interference. The transmission rate of the R-CQICH is determined using the information obtained in the above procedures 200 to 208. That is, the base station determines the transmission rate of the R-CQICH by using some or all of the obtained power amount information, Walsh code information, CQICH interference information, data service type, and total number of terminals in step 210, and in step 212. The transmission rate of the determined R-CQICH is transmitted to the terminal. The determined rate of R-CQICH may be applied to each terminal or a specific group of terminals, or may be simultaneously applied to all user terminals.

A method of determining a transmission rate of the R-CQICH using the power amount information allocated to the packet data service at the base station obtained in step 200 and the interference amount measurement of the R-CQICH obtained in step 204, is performed (step 210). The explanation is as follows. Here, a case of simultaneously applying the transmission rate of the determined CQICH to all user terminals will be described. In addition, it is obvious that the transmission rate of the R-CQICH can be determined by a combination other than the described combination.

First, when the parameters to be used are defined, the case where the ratio of the base station power allocated to the packet data service to the total base station power amount is 50% is called P1 (50%), and the case where 30% is called P2 (30%), The case of 10% is called P3 (10%). And it is assumed that the amount of power obtained in the process 200 of FIG. 2 is Pm. In addition, when the sum of the interference amount (measurement value) of the R-CQICH of each terminal is expressed as the ratio of the base station thermal noise, when the ratio value is 1dB, T1 (1dB), 0.5dB T2 (0.5dB), If 0.25dB, it is assumed to be T3 (0.25dB). Meanwhile, it is assumed that the value obtained in step 204 of FIG. 2 is Tm.

In the following equation, a method of determining the transmission rate of the R-CQICH using the value obtained in step 200 and the value obtained in step 204 is represented by the following equation.

if (Pm> = P1 (50%)) then, R-CQICH baud rate = 800 Hz

else if (Pm> = P2 (30%)) {

if (Tm> = T1 (1dB)) then, R-CQICH baud rate = 400Hz

else R-CQICH Baud Rate = 800 Hz

}

else if (Pm> = P3 (10%)) {

if (Tm> = T1 (1dB)) then, R-CQICH baud rate = 200Hz

else if (Tm> = T2 (0.5dB)) then, R-CQICH baud rate = 400Hz

else R-CQICH Baud Rate = 800 Hz

}

else {

if (Tm> = T1 (1dB)) then, R-CQICH baud rate = 100Hz

else if (Tm> = T2 (0.5dB)) then, R-CQICH baud rate = 200Hz

else if (Tm> = T3 (0.25dB)) then, R-CQICH baud rate = 400Hz

else R-CQICH Baud Rate = 800 Hz

}

3 is a flowchart illustrating the above equation, and illustrates a procedure for determining an R-CQICH transmission rate by using a power amount of a base station and an interference amount of a reverse channel R-CQICH.

Referring to FIG. 3, the base station first determines the amount of power Pm of the base station allocated for the packet data service in step 300, and measures the amount of interference Tm of the reverse channel R-CQICH in step 302. Then, the base station determines whether the measured power amount Pm is greater than P1 (50%), greater than P2 (30%), greater than P3 (10%) or less than P3 (10%) in step 304. Decide if First, after dividing according to the value of Pm, the transmission rate of R-CQICH is determined as 800Hz, 400Hz, 200Hz, or 100Hz based on the measured interference amount Tm in each divided state.

If the determined power amount Pm is greater than or equal to a predetermined reference value P1 (50%), the base station proceeds to step 328 and sets the transmission rate of the R-CQICH to 800 Hz. If Pm is not greater than P1 (50%) and Pm is greater than or equal to P2 (30%), the base station proceeds to step 308 and compares the measured interference amount Tm with a predetermined reference value T1 (1dB). If the interference amount Tm is greater than T1 (1 dB), the base station proceeds to step 330 to set the transmission rate of the R-CQICH to 400 Hz, otherwise proceeds to step 328 to set the transmission rate of the R-CQICH to 800 Hz. Decide on

If the determined power amount Pm is not greater than the predetermined reference value P2 (30%) and Pm is greater than or equal to P3 (10%), the base station proceeds to step 312 and the measured interference amount Tm and the predetermined reference value. Compare T1 (1 dB). If the interference amount Tm is greater than the T1 (1 dB), the base station proceeds to step 332 to determine the transmission rate of the R-CQICH to 200 Hz, otherwise proceeds to step 326 to determine the interference amount Tm. Compare with reference value T2 (0.5dB). If the interference amount Tm is greater than the T2 (0.5 dB), the base station proceeds to step 330 to determine the transmission rate of the R-CQICH to 400 Hz, otherwise proceeds to step 328 to the R-CQICH. Determine the transmission rate of 800Hz.

On the other hand, if the determined power amount Pm is smaller than a predetermined reference value P3 (10%), the base station proceeds to step 314 and compares the measured interference amount Tm with a predetermined reference value T1 (1dB). If the measured interference amount Tm is greater than T1 (1dB), the base station proceeds to step 334 and determines the transmission rate of the R-CQICH to 100 Hz, otherwise proceeds to step 318 and the interference amount Tm. And T2 (0.5dB). If the Tm is greater than T2 (0.5 dB), the process proceeds to step 332 to determine the transmission rate of the R-CQICH to 200 Hz, otherwise proceeds to step 320 to determine the interference amount Tm and the predetermined reference value T3 (0.25 dB). Compare. If the Tm is greater than the T3 (0.25 dB), the process proceeds to step 330 to set the transmission rate of the R-CQICH to 400 Hz, otherwise proceeds to step 328 to determine the transmission rate of the R-CQICH to 800 Hz.

As in the above embodiment, the transmission rate of the R-CQICH may be applied in four cases of 800 Hz, 400 Hz, 200 Hz, and 100 Hz or more in detail. Meanwhile, as in the above embodiment, the determined transmission rate may be directly transmitted. Alternatively, information indicating an increase or decrease in a transmission rate relative to the existing transmission rate may be transmitted.

Hereinafter, a method of transmitting the R-CQICH data rate determined as described above will be described.

For example, if the R-CQICH transmission rate is four types of 800Hz, 400Hz, 200Hz, 100Hz can be represented by 2 bits. In order to transmit the rate information of the R-CQICH to all terminals, a channel for broadcasting to all terminals is required. In an embodiment of the present invention, a "packet data control channel" of L3NQS, which is a post-security of a 1xEV-DV system, is used. The role of the packet data control channel is to transmit information on the packet data channel and is transmitted to the terminal together with the packet data channel. Another role of the packet data control channel is to transmit Walsh Space Indicator (Walsh Space Indicator) used for the packet data channel at regular time intervals. As an example, a method of transmitting the R-CQICH rate information together with each other when the packet data control channel broadcasts the Walsh space information may be used. Table 1 below shows message fields of a packet data control channel used in the present invention.

Field Length (bits) Value WALSH_SPACE_INDICATION_ID 6 000000 WALSH_SPACE 5 XXXXX R-CQICH_DATA_RATE 2 ## Total 13 000000XXXXX ##

Table 1 illustrates a case in which a message field of a packet data control channel transmitting 13 bits of information transmits Walsh space information to all terminals. The rate information of the R-CQICH is expressed using a part of the corresponding field. When the "WALSH_SPACE_INDICATION_ID" field is expressed as 000000, it means that 5 bits of "WALSH_SPACE" information is transmitted as xxxxx. In this case, the "R-CQICH_DATA_RATE" field indicates the R-CQICH transmission rate as 2 bits as ##. For example, the bit representation of the R-CQICH_DATA_RATE field may be represented as 800 Hz for 00, 400 Hz for 01, 200 Hz for 10, and 100 Hz for 11. In other words, when the increase / decrease of the R-CQICH transmission rate is expressed, 00 may be increased, 11 is decreased, and 01 may be maintained at the current state.

When the R-CQICH transmission rate is determined and transmitted as described above, the terminal receives the information on the R-CQICH transmission rate and controls the transmission rate of the R-CQICH according to the transmission rate of the received information.

4 illustrates a procedure for receiving reverse channel R-CQICH rate information from a terminal, which is a forward receiving terminal, and controlling a rate of reverse channel R-CQICH using this information, according to an embodiment of the present invention.

Referring to FIG. 4, the terminal first receives R-CQICH rate information from the base station in step 400. As described above, the transmission rate information is transmitted in a message of a packet data control channel shown in Table 1. That is, the terminal receives the message of the packet data control channel, analyzes the message and obtains information of the R-CQICH_DATA_RATE field in the message when MAC_ID information is 000000. Thereafter, the terminal determines a transmission period of the R-CQICH based on the obtained R-CQICH rate information in step 402. In this case, the information representation to be transmitted should be applied differently according to the representation form of the information of the transmitted R-CQICH. When the information on the transmitted R-CQICH means channel state information itself measured at every transmission period, the measured value may be transmitted at each transmission period of the determined R-CQICH. However, when the currently transmitted channel condition information is transmitted with a relative increase or decrease of the previously transmitted channel condition information, a value for the increase and decrease of the channel condition should be newly set according to the R-CQICH transmission rate. For example, if the R-CQICH data rate is 800Hz, the increase / decrease is shown at +/- 0.5dB interval. If the R-CQICH data rate is reduced to 400Hz, it is readjusted at +/- 1dB interval. Thereafter, in step 404, the R-CQICH information is transmitted to the base station at the reset R-CQICH transmission rate.

5 shows an apparatus of a mobile station for controlling and transmitting a transmission rate of an R-CQICH according to an embodiment of the present invention. The apparatus of the mobile station includes an R-CQICH symbol encoder 500, a sequence repeater 502, a signal point mapper 504, and a Walsh code spreader. 506, a channel gain controller 508, a best sector indicator Walsh Cover 510, and an R-CQICH rate controller 512.

Referring to FIG. 5, the R-CQICH rate controller 512 first determines an update period of transmission information of an R-CQICH and an update period of an optimal packet data transmission sector by using uplink R-CQICH rate information. If R-CQICH transmission rate is 800 Hz, update is performed at 1.25 ms (N = 1) period interval, which is 1 slot. If R-CQICH transmission rate is 400 Hz, 2 x 1.25 ms (N = 2) interval interval is 2 slot. If the R-CQICH transmission rate is 200 Hz, the transmission information is updated at intervals of 4 x 1.25ms (N = 4) which is 4 slots. If the R-CQICH transmission rate is 100 Hz, 8 x 1.25 is the 8 slot. Forward channel status information is updated at intervals of ms (N = 8). Five-bit information indicating the updated forward channel condition for every N slots is input to the R-CQICH symbol encoder 500.

The encoder 500 encodes the input CQICH information (5 bits) and outputs code symbols. The optimal sector indicator 510 inputs an optimal sector indicator indicating a base station having the best forward channel condition, and outputs a Walsh cover corresponding to the input optimal sector indicator. The multiplier 510 multiplies the code symbols from the encoder 500 by the Walsh cover from the optimal sector indicator 410. The multiplier 501 generates a 96-bit sequence by multiplying the Walsh code consisting of 12 code symbols output from the encoder 500 and 8 bits output from the optimal sector indicator 510. The sequence repeater 502 repeatedly outputs the 96-bit input sequence from the gomper 501 N times.

The sequence output number N (repeat count) is determined by the R-CQICH rate controller 512. When the transmission rate of the R-CQICH is 800 Hz, N = 1, 400 Hz, N = 2, 200 Hz, N = 4, and 100 Hz, N = 8. A signal point mapper 504 maps bit 0 to +1 and bit 1 to 1 during the output of the sequence iterator 502. The Walsh code spreader 506 multiplies the output of the signal mapper 504 by the Walsh code of 16 chips and outputs the multiplied signal. A channel gain controller 508 multiplies the output of the Walsh code spreader 506 by the channel gain Gn and outputs the gain. The channel gain Gn is determined by the R-CQICH rate controller 512, which is set differently according to the R-CQICH rate.

For example, FIG. 6A shows a channel gain (Gn) when the R-CQICH data rate is 800 Hz, and shows that the R-CQICH information is newly updated and transmitted for one slot every 800 Hz. FIG. 6B shows the channel gain when the R-CQICH transmission rate is 400 Hz, and shows that the R-CQICH information is newly updated every 400 Hz, and the updated information is transmitted for 2 slots. 6A and 6B, the amount of power required to transmit the same amount of R-CQICH information for one slot regardless of the R-CQICH transmission rate is twice as much as the amount of power required for two slots. many. Therefore, the channel gain Gn is 1, 400 Hz when the R-CQICH data rate is 800 Hz. At 200 Hz , And at 100 Hz Becomes

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. 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.

In the present invention as described above, particularly in a mobile communication system for supporting a high-speed packet data service and a voice data service, the forward transmitting end determines the R-CQICH transmission rate of the terminal and transmits it to control the R-CQICH transmission rate of the terminal Therefore, first, as the number of base station resources available for packet data service in the forward transmitting end is low, there is an advantage that the transmission rate of the reverse R-CQICH can be freely adjusted. In addition, there is an advantage that the amount of interference of the reverse channel can be adjusted by adjusting the transmission rate of the reverse R-CQICH. In addition, in controlling the transmission rate of the reverse R-CQICH, control information is transmitted in the physical layer, so that there is an advantage in that fast control can be performed.

Claims (8)

In a mobile communication system supporting a high speed data service and a voice service, a method for a base station to determine and transmit a transmission rate of a reverse channel quality indication channel (R-CQICH) for transmitting forward channel state information, Determining a transmission rate of the reverse channel quality indication channel based on the amount of power available for packet service and the interference amount of the measured reverse channel quality indication channel; And transmitting a transmission rate of the determined reverse channel quality indication channel to the terminal. The method of claim 1, The transmission rate of the determined reverse channel quality indication channel is characterized in that any one of 800Hz, 400Hz, 200Hz, 100Hz. The method of claim 1, And the transmission rate of the determined channel quality indication channel is transmitted to the terminal through a packet data control channel. In a mobile communication system supporting a high speed data service and a voice service, a method for a base station to determine and transmit a transmission rate of a reverse channel quality indication channel (R-CQICH) for transmitting forward channel state information, A process of determining the transmission rate of the reverse channel quality indication channel in consideration of the amount of power available for the packet service and the number of Walsh codes, the amount of interference of the measured reverse channel quality indication channel, the type of packet data service, and some or all of the total number of terminals. and, And transmitting a transmission rate of the determined reverse channel quality indication channel to the terminal. The method of claim 4, wherein The transmission rate of the determined reverse channel quality indication channel is characterized in that any one of 800Hz, 400Hz, 200Hz, 100Hz. The method of claim 4, wherein And the transmission rate of the determined channel quality indication channel is transmitted to the terminal through a packet data control channel. In a mobile communication system supporting high-speed data service and voice service, a mobile station receives information about a rate of a reverse channel quality indication channel (R-CQICH) for transmitting forward channel state information and applies it to R-CQICH transmission. In the method, Receiving information on a transmission rate of the reverse channel quality indication channel from a base station; Setting a transmission period of the reverse channel quality indication channel according to the received information; And transmitting the reverse channel quality indication channel according to the set transmission period. In a mobile communication system supporting high-speed data service and voice service, a mobile station receives information about a rate of a reverse channel quality indication channel (R-CQICH) for transmitting forward channel state information and applies it to R-CQICH transmission. In the apparatus, A rate controller for determining a transmission period of transmission information of the reverse channel quality indication channel based on information on a transmission rate of the reverse channel quality indication channel from a base station; An encoder which encodes channel quality indication (CQI) information generated at each transmission period and outputs code symbols; A multiplier for multiplying the code symbols from the encoder by the Walsh cover indicating an optimal sector; A sequence repeater for repeatedly outputting an output sequence of the multiplier by a repetition number determined according to the transmission period; A Walsh spreader for Walsh spreading the output of the sequence repeater; And a gain adjuster for multiplying an output sequence of the Walsh spreader by a channel gain determined according to the transmission period and adjusting the gain.