KR20020035310A - Apparatus and method for fast controlling of forward link power using variable rate supplemental channel in mobile communication system - Google Patents

Abstract

PURPOSE: A high-speed forward power control apparatus and method in a mobile communication system using a variable rate supplemental channel is provided to control forward power after exactly judging the state of a channel according to a transfer rate. CONSTITUTION: A forward transmitter consists of an encoder(101), a symbol repeater(103), an interleaver(105), a controller(109), a variable rate information bit generator(111), and a variable rate information bit inserter(107). The encoder(101) encodes received data and outputs symbol data. The symbol repeater(103) repeats and outputs the encoded and outputted symbol data. The interleaver(105) interleaves and outputs the symbols inputted from the symbol repeater(103). The controller(109) receives transfer rate information from an upper layer and outputs a control command to generate and insert variable rate information bits. The variable rate information bit generator(111) generates and outputs variable rate information bits by the control of the controller(109). The variable rate information bit inserter(107) is composed of a puncturer(121) and a MUX(123). The puncturer(121) receives the symbol stream outputted from the interleaver(105) and punctures required intervals by the frame. The MUX(123) inserts the variable rate information bits into the punctured intervals.

Description

High speed forward power control device and method in mobile communication system using variable bit rate supplemental channel {APPARATUS AND METHOD FOR FAST CONTROLLING OF FORWARD LINK POWER USING VARIABLE RATE SUPPLEMENTAL CHANNEL IN MOBILE COMMUNICATION SYSTEM}

The present invention relates to a power control apparatus and method of a mobile communication system, and more particularly, to a variable rate supplemental channel (Variable Rate Supplemental Channel) for transmitting data variably to carry information on the variable rate and transmit the variable rate information The present invention relates to an apparatus and a method for controlling forward power according to a transmission rate.

IMT-2000 system is able to use supplemental channel for high speed data service. In the IS2000.2 Release 0 standard, a base station schedules transmission of a supplemental channel for a plurality of mobile terminals. That is, the base station informs the mobile station in advance of the transmission rate and transmission time of the transmitted data through a control message. Here, the data rate is fixed unchanged during the transmission period. However, the channel conditions of the system and the load of the system may change over a specified transmission interval and the base station may not have enough power to transmit at the specified data rate. In this case, the base station may stop the transmission of the frame by switching the auxiliary channel to the discontinuous transmission mode for a while. However, this method wastes orthogonal codes assigned to users and introduces delays in data transmission. Another method is for the base station to stop transmitting this auxiliary channel and rescheduling the auxiliary channel of the new rate. However, this method also reduces the waste of the first method to some extent and makes it difficult to support the original high-speed data service when the channel condition is improved again. Accordingly, in the current IS-2000.2 Release A standard, the base station can change the transmission rate of the auxiliary channel every 20ms frame in consideration of the channel change state and the system load. That is, the base station can change the data rate according to the situation among several data rates promised with the terminal, so that the original high speed data service is supported when the channel is in good condition, and the transmission is not stopped when the channel is in poor condition. It is possible to transmit at a lower data rate.

Conventional methods of varying the transmission rate of an auxiliary channel for performing high speed data transmission cause problems in forward power control. In IS-2000, forward power control of the channel transmitting voice and the channel transmitting data can be independently performed. To this end, it is necessary to measure the state of the auxiliary channel for transmitting data. If the data rate is randomly changed, it becomes difficult for the terminal to accurately measure the state of the channel. For example, if the transmission rate is cut in half, the power transmitted by the base station is also cut in half and the signal to interference ratio (SIR) indicating the state of the channel is also cut in half. At this time, the terminal compares the SIR value given in half with a predetermined specific threshold value to determine whether the channel is good or bad, and thus power control is not performed properly. That is, since the threshold value remains and the SIR value is cut in half, the mobile station transmits the forward power control command according to the bad decision to the base station, thereby unnecessarily increasing power.

In order to solve the above problem, the current IS-2000.2 Release A standard does not allow independent power control of the supplemental channel when the supplemental channel supports a variable data rate.

However, even if the auxiliary channel supports a variable data rate, if forward power control can be performed as in the case of a fixed data rate, the capacity of the entire system will be increased and more efficient operation of the IMT-2000 system will be possible.

Accordingly, an object of the present invention is to provide a power control apparatus and method of a mobile communication system capable of accurately determining a state of a channel according to a transmission rate in a mobile communication system supporting a variable rate supplemental channel and controlling forward power based on the same. Is in.

Another object of the present invention is to provide a power control apparatus and method of a mobile communication system in which a base station of a mobile communication system supporting a variable rate supplementary channel configures a frame including rate information and informs a terminal.

Another object of the present invention is to provide a terminal of a mobile communication system that supports a variable rate auxiliary channel and includes a base station for transmitting a frame including rate information, and detects rate information from a frame received from a base station through a supplemental channel. A power control apparatus and method of a mobile communication system for power control by selecting a threshold value according to the rate information.

In order to achieve the above object of the present invention, the present invention provides a transmitter of a mobile communication system using a variable rate supplemental channel, comprising: a rate information bit generator for generating a rate information bit according to the rate; And a bit rate information bit inserter for inserting the generated bit rate information bits into a specific position of the frame in frame units according to the bit rate.

In order to achieve another object of the present invention, the present invention provides a transmitter of a mobile communication system using a variable rate supplemental channel, a rate information bit generator for generating a rate information bit according to the rate, and a previous frame during data transmission. And a bit rate information bit inserter for determining the insertion position of the bit rate information bit according to the scrambling code and the maximum bit rate, and inserting the generated bit rate information bit into a position within the determined frame on a frame-by-frame basis according to the bit rate. It is done.

In order to achieve another object of the present invention, the present invention uses a variable rate supplemental channel, and inserts and transmits the generated bit rate information bit at a specific position of the frame in frame units according to the bit rate during data transmission. A receiver of a transmitter communication system of a mobile communication system comprising a transmitter, the receiver comprising: a rate information detector for detecting the rate information bit on a frame basis from an orthogonal despread traffic channel to determine a rate of the supplemental channel; It has threshold values for each of the transmission rates of the supplemental channel, and the signal-to-noise ratio obtained according to the symbol energy of the supplemental channel measured in units of the power control group, The power control unit sends a power control command in comparison with the threshold. It is characterized by loosening.

In order to achieve another object of the present invention, the present invention uses a variable bit rate supplemental channel, and determines the insertion position of the bit rate information bit according to the scrambling code and the maximum bit rate of a previous frame during data transmission. A transmitter of a mobile communication system having a transmitter for inserting and transmitting the rate information bits at a position within the determined frame on a frame-by-frame basis, the receiver of the mobile communication system, wherein the rate is determined by the scrambling code and the maximum rate of the previously received frame. A rate information detection unit for obtaining an information bit insertion position and detecting the rate information bit from the bit rate information bit insertion position in a frame from an orthogonal despreading supplemental channel to determine a transmission rate of the supplemental channel; Rate of mental channel The power control command has a threshold value for and compares the signal-to-noise ratio obtained according to the symbol energy of the supplemental channel measured in units of the power control group and the interference amount of the despread received signal and the threshold value according to the transmission rate. Characterized in that consisting of a power control unit for transmitting.

1 is a block diagram illustrating a configuration of a base station transmitter of a mobile communication system for inserting and transmitting bit rate information bits for controlling forward power using a variable bit rate supplemental channel according to an exemplary embodiment of the present invention.

2 is a diagram illustrating a method for determining a variable bit rate bit insertion position for indicating a bit rate of a channel in a mobile communication system using a variable bit rate supplemental channel according to an exemplary embodiment of the present invention.

3 is a diagram illustrating a method for inserting variable bit rate information bits according to a variable bit rate according to an exemplary embodiment of the present invention.

4 is a diagram illustrating a configuration of a receiver of a mobile terminal of a mobile communication system using variable rate information of a variable rate supplemental channel according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, a detailed description of preferred embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the same reference numerals in the drawings denote the same reference numerals, even if shown in different drawings.

In the following description, specific details such as the number of consecutive intervals of the rate information bits or the position at which the rate information bits are inserted to indicate the data rate of the channel are shown to provide a more general understanding of the present invention. It will be apparent to those skilled in the art that the present invention may be readily practiced without these specific details or by modifications thereof.

Further, in the following description, the term "forward link" means a link transmitted from a base station to a terminal, and the term "reverse link" means a link transmitted from a terminal to a base station.

1 is a diagram illustrating a configuration of a forward transmission device, that is, a base station transmission device according to an embodiment of the present invention. Hereinafter, referring to FIG. 1, the encoder 101 encodes received data and outputs symbol data. As the encoder, a convolutional encoder and a turbo encoder are used. The symbol repeater 103 repeatedly outputs the encoded symbol data to be transmitted according to a transmission rate. The interleaver 105 interleaves and outputs the symbols output from the symbol repeater 103. The interleaver 103 may use a block interleaver. The controller 109 receives the rate information from the upper layer and outputs a control command for generating and inserting the variable rate information bits. The variable rate information generator 111 generates and outputs variable rate information bits under the control of the controller 109. The variable bit rate information bit inserter 107 inserts and outputs variable bit rate information bits generated from the variable bit rate information bit generator 111 under the control of the controller 109 into a symbol string output from the interleaver 105. do. In detail, the variable bit rate information bit inserter 107 inserts the variable bit rate information bits after puncturing a predetermined interval in a frame unit. The variable bit rate information bit inserter 107 receives the symbol strings output from the interleaver 105 and punctures a predetermined section in a frame unit to output the puncturing section 109 and the variable bit rate information in the punctured section. The mux 123 may be configured to insert and output a bit.

The method of inserting the variable bit rate information bit will be described in detail with reference to FIG. 2 below. 2 is a diagram illustrating a frame structure of a supplemental channel into which variable bit rate information bits are inserted according to an embodiment of the present invention.

Referring to FIG. 2, the supplemental channel is scrambled by different long codes allocated to each user. The insertion position of the rate information bit is determined by the long code. The supplemental channel consists of frames divided into 20ms in length and each frame consists of 16 power control groups (PCGs). Even if the supplemental channel supports a variable rate, the rate of the supplemental channel may change every 20ms frame, and the rate does not change within one frame. Therefore, the rate information bit indicating the rate of the supplemental channel may be inserted only once every 20 ms. In the present invention, there are two methods for determining the insertion position of the rate information bits. In the first method, the rate information bits can be inserted into the first power control group of every 20ms frame to minimize the delay time of the fast power control. That is, the receiving end may detect the transmission rate of the frame by demodulating the transmission rate information bit inserted in the first power control group of every 20ms frame in advance by knowing the insertion position of the transmission rate information bit. In addition, even if the first is unknown, it can be inserted and transmitted to another fixed position by an appointment between the base station and the mobile station.

The second method is to determine the insertion position and transmit the rate information bits according to the long code code rate. Specifically, the position of the rate information bits is determined using the last three bits of the long code used to scramble the symbols of the previous power control group of the power control group into which the rate information bits are inserted.

For example, assuming that the bit rate information bit is set to 2 bits in FIG. 2 and the last three long codes are 011 and the data rate is 1/2, the position where the variable bit rate information bits are inserted is the last 3 bits of the long code. Four bits of variable rate information bits are inserted from a symbol having a value obtained by multiplying the decimal value of the data rate by the inverse of the data rate. Therefore, since the decimal value of the last three bits of the long code is 3 and the data rate is 1/2, the positions where the variable bit rate information bits are inserted are 4 (1 / R * bit rate bit 2 bits) starting from the sixth symbol. . When the data rate is 1/4, the insertion position is 8 symbols starting from the 12th symbol.

FIG. 3 illustrates that insertion positions of the bit rate information bits are the same even if the bit rate is variable according to an embodiment of the present invention. The bit rate is three, rate 1 (Rate 1), rate 2 (Rate 2), and rate 3 (Rate 3). Is a diagram showing the case of). In FIG. 3, "||" represents a start of a frame, and "| |" represents a symbol section.

In FIG. 2, the rate information bits are inserted after channel interleaving. This is because if the rate information bits are inserted before the channel interleaving, the rate information bits cannot be continuously transmitted. The bit rate information bit inserter 107 of FIG. 2 inserts the bit rate information bit as shown in FIG. 3 under the control of the controller 109 according to the bit rate. Initially, the clock input to the rate information bit inserter 107 of FIG. 2 operates in accordance with the rate 3 of FIG. For example, if four bit rate information bits are transmitted and bit rate 1 is used, four coded bits (value of 1 = value of 2 = value of value = 4) having the same value in one symbol are inserted. In practice, however, it appears as if one coded bit has been inserted. Therefore, the insertion position determination of the bit rate information bit described above is determined by the bit rate 3 of FIG. That is, the insertion position of the bit rate information bit is determined based on a symbol having a high bit rate. Therefore, in the case of FIG. 3, the receiving end also needs to determine the position of the rate information bit based on the rate 3 and detect the rate information bit from the determined position.

4 is a block diagram illustrating a communication device of a receiver according to an embodiment of the present invention. Hereinafter, the configuration and operation of a receiver according to the present invention will be described in detail with reference to FIG. 2.

Referring to FIG. 4, the PN despreader 401 performs a PN despreading of the received supplemental channel and outputs it. The traffic Walsh despreader 403 performs orthogonal despreading on the received supplemental channel and outputs the orthogonal despreading. The channel measurer 405 measures the channel state of the received signal and outputs a compensation signal according to the measured channel state. The multiplier 409 receives the orthogonal despreading supplemental channel and the compensation signal, and compensates and outputs the orthogonal despreading supplemental channel by the compensation signal. The interferometer 407 of FIG. 4 measures the amount of interfering signal as part of measuring the interference to measure the SIR (signal-to-interference ratio) of the receiving channel. The rate information bit position detector 411 determines a position at which a rate information bit indicating a rate of a supplementary channel is inserted from the supplemental channel input from the multiplier 409. The bit rate information bit position detector 411 inserts bit rate information bits using the last three long codes of the previous power control group of the power control group into which the bit rate information bits are inserted as described in detail in the second method of FIG. Finds the extracted location and extracts it. In the first method described above with reference to FIG. The rate meter 413 determines the rate of the supplemental channel from the extracted rate information bits. The energy meter 415 accumulates the symbol energy of the received supplemental channel for each power control unit and measures the signal strength of the received auxiliary channel. That is, when the power control is performed at 800Hz, the cumulative period of the symbol is 1.25ms. The comparator 417 determines whether the channel is in a good or bad state by using the transmission rate of the supplemental channel extracted above, the signal strength, and the amount of interference. That is, the signal-to-interference ratio is obtained by dividing the amount of energy transmitted from the energy meter by the amount of interference transmitted from the interferometer, and comparing the signal-to-interference ratio with a specific threshold to determine the good and bad of the currently received channel. do. At this time, the size of the threshold to be compared varies according to the transmission rate of the received auxiliary channel. For example, if there are three possible variable bit rates of the auxiliary channel, there are three possible threshold values, where the threshold value is selected as a value corresponding to each bit rate. At this time, the selection of the threshold value is determined by the rate measured by the rate meter. When the comparator 417 determines the good and bad of the receiving channel, the result is sent to the power control command inserter 419 to insert the power control command into the reverse power control sub-channel. . The power control command inserted into the reverse power control subchannel is transmitted to the base station in the reverse direction through the reverse transmitter 421.

As described above, when the transmitter and the receiver support the variable bit rate auxiliary channel, the state of the channel can be accurately determined by detecting the bit rate of the auxiliary channel. Accordingly, even when the auxiliary channel is transmitted at the variable bit rate, efficient power control can be achieved. There is an advantage to this.

Claims (6)

In a transmitter of a mobile communication system using a variable rate supplemental channel, A rate information bit generator for generating a rate information bit according to the rate; Transmitter of a mobile communication system using a variable rate supplementary channel, characterized in that it comprises a bit rate information bit inserter for inserting the generated bit rate information bits at a specific position of the frame in frame units according to the bit rate during data transmission. . In a transmitter of a mobile communication system using a variable rate supplemental channel, A rate information bit generator for generating a rate information bit according to the rate; In the data transmission, the insertion rate of the bit rate information bit is determined by the scrambling code and the maximum bit rate of the previous frame, and the bit rate information bit is inserted to insert the generated bit rate information bit at the position in the determined frame in units of frames according to the bit rate. Transmitter of a mobile communication system using a variable bit rate supplemental channel characterized in that it comprises a portion. A transmitter using a variable rate supplemental channel and including a transmitter for inserting the generated bit rate information bit into a specific position of the frame in frame units according to the bit rate during data transmission to transmit the data. In the receiver, A rate information detector for detecting the rate information bits in units of frames from an orthogonal despread traffic channel to determine a rate of the supplemental channel; Threshold values for each of the transmission rates of the supplemental channel, and the signal-to-noise ratio and the transmission rate obtained according to the symbol energy of the supplemental channel and the interference amount of the And a power control unit for transmitting a power control command in comparison with a threshold value according to the receiver. By using a variable bit rate supplemental channel and determining the insertion position of the bit rate information bit according to the scrambling code and the maximum bit rate of the previous frame during data transmission, the bit rate information bit at a position within the determined frame in frame units according to the bit rate is determined. In the receiver of the mobile communication system of the mobile communication system having a transmitter for inserting and transmitting a receiver, The bit rate information bit insertion position is obtained by the scrambling code and the maximum bit rate of the previously received frame, and the bit rate information bit is detected from the bit rate information bit insertion position in a frame from an orthogonal despreading supplemental channel. A rate information detector for determining a rate of the mental channel; Threshold values for each of the transmission rates of the supplemental channel, and the signal-to-noise ratio and the transmission rate obtained according to the symbol energy of the supplemental channel and the interference amount of the And a power control unit for transmitting a power control command in comparison with a threshold value according to the receiver. A high speed forward power control method in a transmitter of a mobile communication system using a variable rate supplemental channel, Generating a rate information bit for generating a rate information bit according to the rate; Determining the insertion position of the bit rate information bit according to the scrambling code of the previous frame and the maximum bit rate during data transmission, and inserting and transmitting the generated bit rate information bit at a position within the determined frame in frame units according to the bit rate. Characterized in that the process. By using a variable bit rate supplemental channel and determining the insertion position of the bit rate information bit according to the scrambling code and the maximum bit rate of the previous frame during data transmission, the bit rate information bit at a position within the determined frame in frame units according to the bit rate is determined. In the high-speed forward power control method in the receiver of the transmitter mobile communication system of the mobile communication system having a transmitter for transmitting and inserting the; The bit rate information bit insertion position is obtained by the scrambling code and the maximum bit rate of the previously received frame, and the bit rate information bit is detected from the bit rate information bit insertion position in a frame from an orthogonal despreading supplemental channel. Determining the bit rate of the mental channel, Threshold values for each of the transmission rates of the supplemental channel, and the signal-to-noise ratio and the transmission rate obtained according to the symbol energy of the supplemental channel and the interference amount of the And transmitting the power control command in comparison with the threshold value.