KR20000004888A - Forward link power control device of cdma mobile communication system and forward link power control method - Google Patents

Abstract

PURPOSE: A forward link power control device of CDMA mobile communication system investigates a pilot channel and a traffic channel of a forward link, and determines a power control bit for a power control of a forward link. CONSTITUTION: A forward link power control device includes a power control bit detector(160) for detecting only a certain bit whose receiving code symbol's transmission rate is not changed from a correlation value about a code symbol received from a traffic channel, a power inference part(180) for inferring average value of a received power by using a correlation value about both the output bit of the power control bit detector and the code symbol received via the pilot channel. A comparator(210) compares the average value of the received power with a reference value for a power control, and generates a deviation according to the result. A power control bit generator(220) outputs a predetermined power control bit according to the deviation from the comparator. Accordingly, the forward link power control device inferences a power from a code symbol of the received CDMA signal via a traffic channel and a pilot channel, determines a power control bit, and enhances a system performance of the entire system when controlling a power between the mobile station and the base station.

Description

Apparatus and method for controlling forward link power in a CDA mobile communication system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system. In particular, in a mobile communication system using a CDMA scheme, a forward link of a CDMA mobile communication system determines power control bits for power control of a forward link by observing a pilot channel and a traffic channel of a forward link. Relates to power control.

In general, in a mobile communication system using a code division multiplex access (CDMA) method such as a cellular mobile communication system or a personal communication service, a plurality of mobile stations may be a base station or a cell site. Through this, a frame composed of symbols representing digitalized voice or other data is transmitted and received.

Such transmission frames are subject to fading through multipath, which is related to the characteristics of the transmission environment that reflects the transmission frame as the mobile station moves, or due to the high transmission power of a particular mobile station. It relates to the interference characteristics to the mobile station.

In addition, if the mobile station uses too low transmit power, the base station receiving the transmitted frame may not be able to recover the data of the frame transmitted from the mobile station, which may result in data loss. In addition, the mobile station's frame transmit power is controlled for complete recovery of data transmitted while minimizing interference between mobile stations.

For the reasons described above, the base station sends a power control command to the mobile station to measure the transmit power from the frame transmitted at the mobile station and adjust the transmit power over each separate channel.

The power control command is a transmit power increase bit or a transmit power decrease bit for maintaining an average value of received power.

1 is a block diagram showing a part of a configuration of a reverse link power control apparatus of a mobile communication system using a CDMA scheme according to the prior art.

Referring to FIG. 1, a spread spectrum CDMA signal transmitted from a mobile station (not shown) is normally received by a reception antenna 20 of a base station through a reverse link CDMA channel, and the received CDMA signal is a high frequency receiver 21. Will undergo downstream frequency processing.

The CDMA signal down-frequency processed by the high frequency receiver 21 is converted into a digital signal by the A / D converter 22, and the PN correlator 23 is provided by a PN code generator (not shown). The PN code is used to correlate the digitally converted CDMA signal.

The output of the PN correlator 23 is provided to the decoder 24 for decoding, and is also provided to the power predicting section 25 for predicting the average received power of the mobile station (not shown) that has transmitted the CDMA signal.

The decoder 27 decodes the code symbol for the received CDMA signal and simultaneously provides code error information (Code Error Metrics) indicating the quality of the CDMA signal to the outer loop power control unit 26.

Accordingly, the outer loop power control unit 26 can know the transmission power sufficient for the mobile station (not shown) to transmit data, and provides the comparison unit 27 with a power control reference value to be used for power control of the reverse link.

The comparison unit 27 compares the average value of the received power of the mobile station (not shown) predicted by the power predicting unit 25 with the power control reference value provided by the outer loop power control unit 26, and compares the power control reference value to the power control reference value. The deviation of the average received power value is provided to the power control bit generator 28.

The power control bit generator 28 provides the transmitter 29 with a received power increase bit or a received power decrease bit according to the deviation provided above.

The transmitter 29 loads the received power increasing bit or the received power decreasing bit outputted from the power control bit generator 28 along with the uplink frequency-processed user data in the traffic channel of the CDMA channel of the forward link and transmits the antenna 30. ) Is sent to the mobile station (not shown).

In this case, the CDMA channel is usually composed of a pilot channel (Pilot ch), a synchronous channel (Synchronous ch), a paging channel (traffic ch), a traffic channel (Traffic ch) for forward access and communication from the base station to the mobile station, these Each of the CDMA channels is orthogonally developed by a Walsh Function code, and then coded into orthogonal pairs of Pseudo Noise (hereinafter, abbreviated as PN) sequences at a fixed chip rate. It is symbolized.

In addition, a CDMA signal having various transmission rates is subjected to an encoding process in a mobile station (not shown), and is usually encoded into a frame having a 20 msec time interval. Here, the rate is 9.6 kbps (full rate), 4.8 kbps (half rate), 2.4 kbps (quarter rate), 1.2 kbps (eighth rate). Error Correcting Code is used.

In FIG. 1, power control through the power predictor 25, the comparator 27, and the power control bit generator 28 is called closed loop power control, which is determined by the base station from the mobile station. After measuring the received power according to the transmission rate of the signal, the base station compares the power control reference value preset for each base station, and sends the appropriate power control command to the mobile station along with user data. According to the transmission power adjusted according to the power control.

Here, in performing the closed loop power control, a different power control reference value is set for each mobile station according to various parameters such as the moving speed of the mobile station, the environment of the mobile station, and the like. The power control reference value is adjusted according to the received data frame error rate. This power control is called outer loop power control.

As such, the power control of the mobile communication using the conventional CDMA scheme is mainly applied to the reverse link, and in order to perform the high speed forward link power control, the mobile station not only needs to measure the power of the CDMA signal received from the base station. In addition, one of the CDMA channels must be observed to determine which one to use for power control.

If the power control of the forward link is performed by observing the traffic channel similarly to the power control of the reverse link, since the traffic channel of the forward link has a variable transmit power according to the transmission rate, transmission of a signal currently received from the mobile station When judging the speed and then performing the power control by calculating the signal-to-interference ratio, there is a large delay in the transmission rate, so that it cannot follow the currently changing CDMA channel environment.

In addition, when the power control bit for power control of the reverse link is transmitted only through the traffic channel, the power control bit has the same power for all transmission rates regardless of the transmission transmission rate. Although power control can be performed by observing the power control bit, the power control bit has a very short length, which causes a large error in calculating the interference ratio for the currently received CDMA signal. There is a problem that the probability of being wrong becomes large.

In addition, when power control is performed by observing a pilot channel instead of a traffic channel, since a pilot channel is a channel commonly used by a plurality of mobile stations belonging to one base station, a plurality of mobile stations independently perform power control. The problem is that you can't.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. In performing power control of a forward link, a CDMA scheme for generating a power control bit for forward link power control by observing both a traffic channel and a pilot channel of a forward link is performed. It is an object of the present invention to provide forward link power control of a mobile communication system.

A forward link power control apparatus of a mobile communication system using a CDMA scheme according to the present invention for achieving the above object is a traffic channel for correlating code symbols received through an arbitrary traffic channel and outputting a correlation value accordingly. A correlation between the correlator, a pilot channel correlator which takes another correlation with respect to code symbols received through any pilot channel, and outputs a correlation value accordingly, and a transmission rate of the received code symbol from the correlation value output from the traffic channel correlator. A power control bit extraction unit for extracting only the unchanged arbitrary bits, a power prediction unit for predicting an average value of the received power using the correlation value output from the pilot channel correlation unit and the bit output from the power control bit extraction unit; Compares the average value of the received power predicted by the power predictor with a reference value for arbitrary power control, And a power control bit generator for outputting an arbitrary power control bit according to the deviation output from the comparator.

A first feature of a forward link power control method of a mobile communication system using a CDMA scheme according to the present invention for achieving the above object is that both the traffic channel and the pilot channel of the forward link is used for power control of the forward link. do.

Advantageously, power control of said forward link utilizes power control bits transmitted for any time of code symbols transmitted on said traffic channel and said pilot channel, respectively. In addition, the ratio of the power of the pilot channel measured for the same time to the power of the traffic channel measured for any time is the same, and other times the hourly traffic channel power measured for any time [T1] The difference between S (T1) / T1] and another hourly traffic channel power [S (T2) / T2] measured during any other time T2 is the pilot channel power [P (T1) per time T1]. / T1] and another difference between the pilot channel power P (T2) / T2 per time T2.

In addition, the forward power control is a period of high probability that the code symbol exists for the current power control group for observing code symbols transmitted through the traffic channel and the pilot channel, respectively during a preset observation period (T1) ( Observe the code symbols during T1-T3), and perform the power control group and any operation for power prediction and power prediction for the code symbols observed during the interval T3 other than the observation interval T1-T3. It is used by dividing.

Alternatively, the forward power control is a period T1 having a high probability that a code symbol exists for a current power control group that observes code symbols transmitted through the traffic channel and the pilot channel, respectively, during a preset observation period T1. Code symbols are observed during the period T3 not used for the observation interval in the previous power control group, and during the period T3 not used for the observation intervals T1-T3 in the current power control group. The power control group is divided and used to perform power prediction and power prediction for the observed code symbol.

A second feature of a method for controlling forward link power of a mobile communication system using a CDMA scheme according to the present invention for achieving the above object is that any of code symbols transmitted through a traffic channel and a pilot channel, respectively, for power control of the forward link. Obtaining a ratio of the signal power transmitted in the interval using the power control bit interval transmitted for the time period, obtaining an average value of the ratio of the previously obtained signal power and the ratio of the signal power, and the signal power Estimating received power using an average value of the ratios, and comparing the estimated signal power value with a reference value to generate a power control bit.

Preferably, in the step of calculating the average value from the ratio of the two signal powers, the average value is a finite impulse response filter (FIR Filter) or an infinite impulse response filter ( IIR Filter).

According to a third aspect of a method for controlling forward link power of a mobile communication system using a CDMA scheme according to the present invention, a power control bit interval of a code symbol transmitted through a traffic channel for power control of a forward link is provided. Estimating the signal power transmitted in a predetermined section and accumulating and averaging the previously estimated signal power value; and estimating the signal power transmitted during a time corresponding to the predetermined section through a pilot channel. Cumulative averaging; calculating a ratio of the cumulative average value of the traffic channel to the cumulative average value of the pilot channel; estimating a received power using the ratio of the cumulative average value; and the estimated received power value and the reference value. Comparing and generating the power control bits.

In order to achieve the above object, a final feature of a method for controlling a forward link power of a mobile communication system using a CDMA scheme according to the present invention is that a pilot channel and a traffic channel are performed for a time longer than a time of a power control group (PCG). In order to know the ratio, the ratio of the pilot channel and the traffic channel obtained from each power control group is used.

Here, when the ratio between the pilot channel and the traffic channel for a time other than the time of the power control group is determined, the average value of the ratio of the pilot channel and the traffic channel obtained in each power control group is used. do.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram showing some components of a reverse link power control apparatus of a mobile communication system using a CDMA scheme according to the prior art.

2 is a block diagram showing a part of a configuration of an apparatus for controlling forward link power of a mobile communication system using a CDMA scheme according to the present invention;

3 illustrates a power control group for observing power control bits on traffic and pilot channels in accordance with the present invention;

4 is a graph showing an example of actual experimental results for forward link power control.

5 is a block diagram showing the configuration of a power predictor used in the forward link power control apparatus according to the present invention;

6 is a block diagram showing the configuration of a power estimator according to another embodiment of the power predictor used in the forward link power control apparatus according to the present invention;

* Description of the symbols for the main parts of the drawings *

130: PN correlator 140: traffic channel correlator

150: pilot channel correlation unit 160: power control bit extraction unit

170: coherent detector 180: power predictor

200: outer loop power control unit 210: comparison unit

220: power control bit generator

Hereinafter, a preferred embodiment of forward link power control of a mobile communication system using a CDMA scheme according to the present invention will be described with reference to the accompanying drawings.

2 is a block diagram showing a part of a configuration of an apparatus for controlling forward link power of a mobile communication system using a CDMA scheme according to the present invention.

The apparatus for controlling forward link power of a mobile communication system using a CDMA scheme according to the present invention is a traffic channel correlator 140 that correlates code symbols received through a traffic channel of a CDMA signal in the conventional configuration shown in FIG. The pilot channel correlator 150 correlates the code symbols received through the pilot channel among the CDMA signals, and the power of which the transmission rate of the received code symbols is not changed among the correlation values output from the traffic channel correlator 140. A power control bit extractor 160 for extracting only control bits and a coherent detector 170 for detecting code symbols to be decoded from an output of the traffic channel correlator 140 and an output of the pilot channel correlator 150. And average power of the mobile station from the power control bits extracted from the output of the traffic channel correlation unit 140 and the output of the pilot channel correlation unit 150. It is configured to include a power estimator (Power Estimator) 180 to predict the power.

The operation of the forward link power control apparatus of the mobile communication system using the CDMA scheme configured as described above will be described.

A spread spectrum CDMA signal transmitted from a base station (not shown) is normally received by the reception antenna 100 of the base station through a CDMA channel, and the received CDMA signal is subjected to downlink frequency processing by the high frequency receiver 110.

Here, the CDMA signal over the CDMA channel is orthogonally developed using a Walsh function.

The CDMA signal down-frequency processed by the high frequency receiver 110 is converted into a digital signal by the A / D converter 120, and the PN correlator 130 is provided by a PN code generator (not shown). The PN code is used to correlate the digitally converted CDMA signal.

After the PN correlation unit 130 undergoes correlation processing, code symbols on a traffic channel and code symbols on a code channel symbolized by a Walsh function are respectively used as traffic channels. The correlation unit 140 and the pilot channel correlation unit 150 undergo a correlation process.

The power control bit extractor 160 extracts only the power control bits of which the transmission rate of the received code symbol does not change among the correlation values output from the traffic channel correlator 140. Is provided to the power estimator 180.

In addition, the output of the pilot channel correlator 150 is provided to the power estimator 180 to utilize the output of the power control bit extractor 160 and the output of the pilot channel correlator 150, thereby providing CDMA. It is possible to estimate the average received power of the mobile station (not shown) that sent out the signal.

The coherent detector 170 detects a reception code symbol to be decoded from the output of the traffic channel correlator 140 and the output of the pilot channel correlator 150, and the decoder 190 may predetermine the received code symbol. The detected code symbol is decoded.

The outer loop power control unit 200 is provided with Code Error Metrics indicating the quality of the CDMA signal received from the decoder 190, and the mobile station (not shown) which transmits the CDMA signal by using the code error metrics is used to receive the signal. By calculating sufficient transmit power to transmit, the calculated transmit power is determined as a power control reference value to be used for power control of the forward link.

The predetermined power control reference value is provided to the comparator 210, and the comparator 210 is an average value of the received power of the mobile station (not shown) predicted by the power predictor 180 and the outer loop power controller 200. ) By comparing the power control reference value provided in the), and outputs a deviation of the received power average value with respect to the power control reference value to the power control bit generator 220.

The power control bit generator 220 outputs the received power increase bit or the received power decrease bit to the transmitter 230 according to the deviation of the average value of the received power from the power control reference value, and the transmitter 230 transmits the uplink frequency-processed user data. And the power control bit generator 220 are transmitted to the base station (not shown) through the transmission antenna 240 together with the reception power increase bit or the reception power decrease bit output from the power control bit generator 220.

Accordingly, the base station (not shown) adjusts the received power according to the received power increase / decrease command, and transmits user data at the transmission rate accordingly.

3 is a diagram illustrating a power control group for observing power control bits on a traffic channel and a pilot channel according to the present invention.

3 is for estimating power on a traffic channel to implement power control of the forward link according to the present invention.

Referring to FIG. 3 (a), the time occupied by the power control group (hereinafter, abbreviated as PCG) is T1 and one power control bit (hereinafter, abbreviated as PCB). This time is occupied by T2, the power during the occupancy time T1 on the pilot channel 300 is P (T1), and the power during the occupancy time T2 on the pilot channel 300 is P (T2), on the traffic channel 400. The power during the time T1 is defined as S (T1), and the power during the occupancy time T2 on the traffic channel 400 is defined as S (T2).

Here, P (T1), P (T2), and S (T2) are values that can be calculated, and S (T1) in a state where the transmission speed of the traffic channel 400 whose transmission power is variable according to the transmission rate of the CDMA signal is unknown. ) Cannot be calculated, so S (T1) must be inferred from P (T1), P (T2), and S (T2).

The first way to infer S (T1) is to assume that the ratio of P (T1) to S (T1) is equal to the ratio of P (T2) to S (T2). Accordingly, Equation 1 is derived.

Using Equation 1, S (T1) can be inferred as follows.

The second method for inferring S (T1) is to use the difference in power value according to the corresponding occupancy time for each occupancy time T1 and T2. Accordingly, Equation 3 is derived.

Using Equation 3, S (T1) can be inferred as follows.

The power predictor described in FIG. 2 predicts the power S (T1) during the occupancy time T1 of the traffic channel 400 by using Equation 2 or Equation 4 and then outputs the power from the outer loop power controller. In comparison with the reference value, the corresponding power control bit is generated according to the deviation between S (T1) and the power control reference value.

For example, the result of performing power control of the forward link using Equation 2 is as follows.

FIG. 4 shows the results of experiments using a case in which the transmission data rate of 9600bps is used in a CDMA mobile communication system using a direct spread of 3.6864Mcps, and the PCG of the reverse link contains three symbols. It is shown.

This means that the channel has only one path when the ratio of received desired energy to interference energy [Ior / (Ioc + No)] is 8 dB, and the mobile station undergoes Rayleigh Fading while moving at a speed of 3 km / h. This is the result of experiment in environment.

As shown in FIG. 4, when no forward link power control is performed, (No PC) performs the worst performance, and then performs forward link power control by observing only the reverse link PCB of three symbols (3symbols in PCG). Shows the next bad performance.

In addition, ideally performing power control of the forward link under the assumption that the data rate of the forward link is known (All symbols in PCG) shows the best performance, and the forward link power control according to the present invention using Equation 2 above. In the case of the Proposed method, there is almost no difference from that of the ideal forward link power control (All symbols in PCG). Therefore, the performance of about 1 dB is improved compared to the case of performing power control using only the PCB.

In Equation 1, the ratio of S (T2) / P (T2) is an instantaneous value of a short time, so the accuracy may be degraded because it may have a lot of influence on noise. Therefore, to increase the accuracy, the values of S (T2) / P (T2) obtained from previous PCGs are used.

That is, the average of the values of S (T2) / P (T2) obtained from previous PCGs can be taken, and the received power can be predicted using the values. At this time, if the average value is taken, the ratio of the signal power which is incorrectly calculated by the noise added to each PCG acts on the average, so the noise is less affected.

5 is a block diagram illustrating a configuration of a power predicting unit used in a forward link power control apparatus according to the present invention.

The power predicting unit 180 illustrated in FIG. 5 includes an average predicting unit 181.

First, the ratio of S (T2) introduced through the power control bit extractor 160 from the traffic channel correlation unit and P (T2) entered from the pilot channel correlation unit 150 is obtained.

The average predictor 181 outputs an average value using the ratio of S (T2) / P (T2), which is the ratio of signal power during T2 time, and the signal power during T2 time previously obtained. Then, as mentioned above, the noise effect is less than the power control when using the ratio of signal power obtained from one PCG.

If the average predictor 181 outputs the output immediately without using the ratio of the signal power for the T2 time previously obtained, power control is performed using the ratio of the signal power obtained from each PCG.

The average predictor 181, which calculates an average value of S (T2) / P (T2), may use a low pass filter (LPF) using a finite impulse response filter (FIR Filter) or an infinite impulse response filter. A low pass filter (LPF) using (IIR Filter: Infinite Impulse Response Filter) may be used.

In the case of using the power predicting unit 180 shown in FIG. 5, when the exact ratio between the signal power of the pilot channel and the signal power of the traffic channel is used for power control of the forward link, the output of point B may be detected and used. In order to obtain S (T1) by applying Equation 2 using P (T1), it may be detected and used at the output A point of the calculation unit 184. Outputs through these points A or B are input to the comparison unit of FIG.

Alternatively, another embodiment in which the power predicting unit 180 can accumulate and use the previous S (T2) / P (T2) as it is in taking the average value of the signal power ratio. This accumulates S (T2) and P (T2), respectively, to find the ratio of each other.

Here, the cumulative value of P (T2) is a value obtained by continuously accumulating a predetermined interval value in the signal of the traffic channel, so that the signal strength of the traffic channel may be known regardless of the transmission speed of the traffic channel. That is, the average signal power of the traffic channel received regardless of the transmission rate can be known as the accumulated value of P (T2).

6 is a block diagram illustrating a configuration of a power estimator according to another embodiment of the power predictor used in the forward link power control apparatus according to the present invention.

According to FIG. 6, the power predicting unit 180 includes a first average predicting unit 182 and a second average predicting unit 183 that obtain averages of P (T2) and S (T2), respectively.

First, the S (T2) coming from the traffic channel correlator 160 through the power control bit extractor 160 obtains an average from the second average predictor 183, and the P (T2) coming from the pilot channel correlator 150 is obtained from the first. After the average is calculated by the average predictor 182, a ratio of signal powers using the average of each is obtained.

The first average predictor 182 and the second average predictor 183, which obtain average values of S (T2) and P (T2), respectively, may use a low pass filter (LPF) using a finite impulse response filter. Alternatively, a low pass filter (LPF) using an infinite impulse response filter (IIR Filter) may be used.

In the case of using the power predicting unit 180 illustrated in FIG. 6, when an accurate ratio between the signal power of the pilot channel and the signal power of the traffic channel is used for power control of the forward link, the output of point B may be detected and used. In order to obtain S (T1) by applying Equation 2 using P (T1), it may be detected and used at the output A point of the calculation unit 184. Outputs through these points A or B are input to the comparison unit of FIG.

However, if one wants to know only the average signal power of the received traffic channel, regardless of the transmission rate, the output of point C may be detected.

In the present invention, when the ratio of S (T2) / P (T2) is needed once for a long time such as one frame rather than for each PCG, the average may be accumulated for a desired time. In this case, when calculating the average value of S (T2) / P (T2), as shown in FIG. 5, the value of S (T2) / P (T2) is accumulated and used for the average value, or as shown in FIG. After accumulating P (T2), respectively, the cumulative value of S (T2) / cumulative P (T2) may be used as the average value.

3A), the present PCG is observed during T1, and power prediction and other processing are performed during the T1 at the next PCG, and then the PCB currently generated in the PCG is performed. Will be added and sent.

As shown in FIG. 3, the PCB for power control of the reverse link always occupies a portion of one PCG on the traffic channel 600, and in the case of the IS-95, randomly located at the front 2/3 of the one PCG. Done. In other words, if a PCG is divided into 24 parts, it is located in any part of the front 16 parts.

Therefore, as shown in FIGS. 3 (b) and 3 (c), since the portion where the actual PCB is located is a certain front side of the PCG, the occupancy time T1 for obtaining power of the pilot channel 500 can be shortened slightly. This allows power prediction and other operations to be performed during the saved time T3.

As a result, in FIG. 3 (b), since T3 can be saved from T1, PCG is observed for (T1-T3) time, and power prediction and other processing are performed during T3 time. By transferring the PCB generated during (T1-T3) time to the next PCG, the time delay can be reduced.

FIG. 3 (c) shows a time T3 which is not used as an observation section in the previous PCG, unlike the case of predicting power by reducing the occupancy time T1 by T3 in order to reduce the time delay as shown in FIG. 3 (b). In this case, the time delay can be reduced even without reducing the occupancy time T1 in estimating power.

As described above, according to the present invention, power is predicted from the code symbols of the CDMA signal received through the traffic channel and the pilot channel of the forward link, and power control bits are determined accordingly. There is an effect that the forward link power control is possible to improve the performance of the.

Claims (12)

A power control bit extracting unit for extracting only an arbitrary bit in which the transmission rate of the received code symbol does not change from a correlation value for the code symbol received through the traffic channel; A power estimator for predicting an average value of received power by using a correlation value between a bit output from the power control bit extractor and a code symbol received through a pilot channel; A comparison unit comparing the average value of the received power predicted by the power prediction unit with a reference value for arbitrary power control, and outputting a deviation according thereto; And a power control bit generator for outputting an arbitrary power control bit according to the deviation output from the comparator. A forward link power control method of a CDMA mobile communication system, characterized by using both a traffic channel and a pilot channel of a forward link for power control of a forward link. 3. The forward link of a CDMA mobile communication system according to claim 2, wherein the power control of the forward link uses a power control bit transmitted for a random time of code symbols transmitted on the traffic channel and the pilot channel, respectively. Power control method. 3. The CDMA movement of claim 2, wherein the forward link power control uses a ratio of the power of the pilot channel measured for the same time to the power of the traffic channel measured for any time. A method of forward link power control in a communication system. 3. The method of claim 2, wherein the forward link power control is such that the hourly traffic channel power [S (T1) / T1] measured for any time T1 and another hourly traffic measured for any other time T2. The difference between the channel power [S (T2) / T2] is the pilot channel power P (T1) / T1 per said time T1 and pilot channel power [P (T2) / T2] per another time T2. A method of controlling forward link power in a CDMA mobile communication system, characterized in that it is equal to the difference of. 3. The method of claim 2, wherein the forward power control exists for the current power control group for observing code symbols transmitted through the traffic channel and the pilot channel, respectively, during a preset observation period T1. Observe the code symbol during a high probability period T1-T3, and perform any operation for power prediction and power prediction for the observed code symbol during a period T3 other than the observation period T1-T3. And dividing and using the power control group to perform the forward link power control method of the CDMA mobile communication system. 3. The method of claim 2, wherein the forward power control exists for the current power control group for observing code symbols transmitted through the traffic channel and the pilot channel, respectively, during a preset observation period T1. Observe the code symbol during the period T3 which is not used for the observation interval in the previous power control group as well as during the high probability period T1-T3, and in the current power control group the observation interval T1-T3. A forward link of the CDMA mobile communication system, characterized in that the power control group is divided and used to perform an arbitrary operation for power prediction and power prediction for the observed code symbol during the period T3 not used. Power control method. Obtaining a ratio of the signal power transmitted in the interval using a power control bit interval transmitted during a certain time period among code symbols transmitted through the traffic channel and the pilot channel for power control of the forward link; Obtaining an average value of the ratio of the previously obtained signal power and the ratio of the signal power; Estimating a received power using the average value of the signal power ratios; And generating a power control bit by comparing the estimated signal power value with a reference value. 10. The method of claim 8, wherein in calculating the average value from the ratios of the two signal powers, the average value is a finite impulse response filter (FIR filter) or an infinite impulse response. A method of controlling forward link power in a CDMA mobile communication system, characterized by obtaining through a filter (IIR Filter). Estimating signal power transmitted in a predetermined period of a power control bit interval among code symbols transmitted through a traffic channel for power control of the forward link, and accumulating and averaging the previously estimated signal power value; Estimating signal power transmitted during a time corresponding to the predetermined period through a pilot channel and accumulating and averaging the previously estimated signal power value; Obtaining a ratio of the cumulative average value of the traffic channels to the cumulative average value of pilot channels; Estimating a received power using the ratio of the cumulative average values; And generating a power control bit by comparing the estimated received power value with a reference value. The forward direction of a CDMA mobile communication system using the pilot channel and traffic channel ratios obtained from each power control group when the ratio between the pilot channel and the traffic channel for a time other than the time of the power control group (PCG) is determined. Link power control method. The method of claim 11, wherein the ratio of the pilot channel and the traffic channel obtained from each of the power control groups is averaged when the ratio of the pilot channel and the traffic channel for a time other than the time of the power control group is calculated. A method for controlling forward link power in a CDMA mobile communication system, characterized by using a value.