KR100320426B1 - Method of determining transmission time of physical channel in wireless communication system - Google Patents

Abstract

The present invention provides a wireless communication for minimizing interference between physical channels by transmitting chips without physical synchronization, with a time delay between physical channels having the same scrambling code, and having a time delay between physical channels having different scrambling codes. The present invention relates to a method for setting a transmission time of physical channels in a system, and the present invention manages the number of physical channels and the number of channel codes assigned to a specific base station so that the number of physical channels of the base station is larger than the number of channel codes. If the scrambling code used between the physical channels to be transmitted is the same, the chip synchronization is transmitted according to the chip synchronization. Otherwise, the scrambling code delays the chip synchronization for the same physical channel.

Description

Method of determining transmission time of physical channels in wireless communication system

The present invention provides a physical channel capable of setting an optimal transmission time so that the scrambling code can set the transmission time of other physical channels in an IMT-2000 wireless access system, so as to be suitable for improving system performance without increasing hardware complexity. It relates to a transmission time setting method.

In the wireless access system of IMT-2000, which is currently being promoted, when a physical channel is transmitted, a plurality of physical channels are transmitted at the same time through the same frequency because each physical channel is identified by a specific code.

Dedicated Physical Channels (DPCHs) are used for both uplink and downlink in the radio access system of the IMT-2000, and these Dedicated Physical Channels (DPCHs) are generally super frames and radio frames. It consists of three hierarchical structures: radio frames and time slots. Here, the Dedicated Physical Control Channel (DPCH) is divided into a Dedicated Physical Data Channel (DPDCH) for transmitting data and a Dedicated Physical Control Channel (DPCCH) for transmitting a control signal.

The radio access system base station transmitter of the IMT-2000 multiplies a unique channel code assigned to each physical channel for each data signal transmitted through the physical channel. Then, since the terminal receiver knows in advance the unique code assigned to the physical channel to be received, the same code is multiplied again with the received signal and then integrated in a bit period. In the IMT-2000 wireless access system, a code consists of a channel code and a scrambling code. In other words, the channel code is first multiplied by the channel code and then the scrambling code by the base station transmitter.

In this case, the chip rate, which is the transmission rate of the code, is higher than the bit rate, which is the transmission rate of the user data bit signal, and a value obtained by dividing the chip rate by the bit rate is called a spreading factor. Spread rate refers to the number of chips in a code that are multiplied by one data bit.

1 is a block diagram of a conventional base station transmitter. Referring to FIG. 1, data input through a plurality of physical channels allocated per base station are converted into parallel data while passing through the serial-to-parallel converters 11-13, respectively. In this case, since two multipliers 21, 22, 23, 24, and 25 and 26 are connected to the output terminal of each serial-to-parallel converter 11-13 to distinguish physical channels, each serial-to-parallel conversion is performed. The output signals of the units 11-13 are multiplied by the orthogonal codes in which the correlation values of each of the multipliers 21-26 become zero, and are spread at the chip rate according to the channel code. Subsequently, the output signals of the multipliers 21-26 are input to the I channel adder 31 and the Q channel adder 32, respectively, to be summed for each channel. Subsequently, respective output signals of the I channel adder 31 and the Q channel adder 32 are added through the adder 34, and the complex scrambling code in the multiplier 35 as shown in FIG. ) Is multiplied and transmitted on each carrier in a state separated into real and imaginary parts.

Here, the channel code is a code having a unique value for each physical channel and assigns a unique orthogonalized code for each physical channel. The IMT-2000 wireless access system uses channel codes within 4 to 512 channels. In addition, the scrambling code serves to distinguish a base station (or cell), and in a radio access system of the IMT-2000, 512 including one primary scrambling code (PSC) and 511 secondary scrambling codes (SSC) per base station is added. Can be used in dogs.

In the radio access system of the IMT-2000, when the number of physical channels per base station is less than the number of orthogonal channel codes, it is preferable to use one scrambling code for one base station.

However, when the number of physical channels of one base station is greater than the number of orthogonalized channel codes, the number of channel codes is insufficient, so a plurality of scrambling codes must be used. Even when multiple scrambling codes are used in one base station, it is desirable to use as few scrambling codes as possible. When two or more scrambling codes are used for a base station, a scrambling code used first is called a primary scrambling code, and an additional scrambling code used is called a secondary scrambling code. There may be 511 secondary scrambling codes per base station. In the present invention, it is assumed that the number of scrambling codes available per base station is M. FIG.

The physical channels of the data signal transmitted through the respective physical channels are spread by the channel code, C_ch, n (n = 1, 2, 3, ... N), and then spread again by the scrambling code. It is modulated by the modulator shown in 2 and then output. At this time, chip synchronization is performed between all physical channels scrambled by the primary scrambling code and the M secondary scrambling codes in the same base station. That is, there is no difference in the starting point of chip transfer.

3 is a diagram illustrating a time interval of a chip transmission start point between physical channels in the case of transmitting physical channels in a conventional base station transmitter. Accordingly, the terminal receiver adjusts the time synchronization of the received signal based on the physical channel scrambled by the primary scrambling code. Therefore, when the base station transmitter transmits data bits using both the primary scrambling code and the secondary scrambling code, the terminal receiver is scrambled with the secondary scrambling code because there is no difference in the chip transmission starting point between all physical channels. It is possible to use the time synchronization of the physical channel scrambled with the first scrambling code, which is already set, without the need to adjust the reception time synchronization of the physical channel.

However, in the related art, even if the same chip synchronization (chip transfer start point) is given between the physical channels scrambled with the primary or secondary scrambling code, the scrambling code does not disappear between the different physical channels. In other words, if the chip is synchronized with the same scrambling code, the amount of interference can be reduced due to the orthogonalized channel code. However, if the scrambling code is different from the physical channel, even if the scrambling code is reversely scrambled in the receiver of the terminal. The scrambling code remains so that the benefits of orthogonalized channel codes are not available.

In addition, when multiplying different scrambling codes by physical channels to transmit chip transmission start points between the respective physical channels according to the same reference point (for example, primary scrambling code), the overall communication quality may be reduced due to interference between the physical channels. There was a problem that went bad.

An object of the present invention has been made in view of the above-mentioned problems of the prior art, and the chip is transmitted in synchronization with the chip synchronization between the physical channels with the same scrambling code, and the time delay between each physical channel with a different scrambling code The present invention provides a method for setting a transmission time of physical channels in a wireless communication system for minimizing interference between physical channels by transmitting without synchronization.

According to an aspect of the present invention for achieving the above object, there is a plurality of scrambling codes assigned to a group of communication channels that can be used in a base station or a cell, each channel has a different channel code In an allocating CDMA wireless communication system, a transmission time setting method of physical channels may be performed when a specific base station manages the number of physical channels allocated to it and the number of channel codes so that the number of physical channels of the base station is larger than the number of channel codes. If the scrambling code used between the physical channels to be transmitted is the same, the chip synchronization is transmitted according to the chip synchronization. Otherwise, the scrambling code delays the chip synchronization for the same physical channel.

1 is a block diagram of a spreader of a conventional base station transmitter.

2 is a block diagram of a modulator of the conventional base station transmitter shown in FIG.

3 is a diagram illustrating a time interval of a chip transmission start point between physical channels when physical channels are transmitted by a conventional base station transmitter.

4 is a block diagram of a modulator of a base station transmitter according to the present invention.

5 is a diagram illustrating a time interval of a chip transmission start point between respective physical channels when transmitting physical channels in a base station transmitter according to the present invention.

6 is a view for showing the received power state of each physical channel when the directivity is different for each scrambling code in the base station transmitter according to the present invention.

FIG. 7 illustrates that when a secondary scrambling code is uniformly transmitted over an entire cell area in an antenna of a base station in the base station transmitter according to the present invention, and another secondary scrambling code is transmitted with directivity for each cell area in an antenna of the base station, each physical A diagram for showing a reception power state of a channel.

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

11-13: serial-parallel converter 21-26, 35: multiplier

31-32: channel summing unit 33: complex processing unit

34: adder 41, 42: time delay

Hereinafter, a configuration and an operation according to a first preferred embodiment of the present invention will be described with reference to the accompanying drawings.

First embodiment

According to a feature of the present invention, if the physical channel transmitted from the base station transmitter and the scrambling code having the same scrambling code is descrambling in the terminal receiver, the scrambling code component is lost, only the channel component remains.

For example, if there is a terminal A, B, C in one base station, each terminal A, B, C receives data from the same base station through their own physical channels Pa, Pb, and Pc, respectively. At this time, each channel code unique to each physical channel = (1, 1, 1, 1), = (1,1, -1, -1), Assuming that = (1, -1, -1, 1), the spreading rate of all channel codes is four.

At this time, the physical channels Pa and Pb are scrambling codes Scrambling, the physical channel Pc is a scrambling code Assume that it is scrambled by. The data transmitted through each physical channel Pa, Pb, and Pc are referred to as Da, Db, and Dc, respectively. Then, all signals of the physical channels Pa, Pb, and Pc are received by the receiver of the terminal A, and the reception components due to each physical channel are represented by Equations 1 to 3 below.

In addition, the received signal of the terminal A The components for each physical channel after inverse scrambling are as shown in Equations 4 to 6 below.

Component after inverse scrambling of received signal component of physical channel Pa:

Component after inverse scrambling among received signal components of physical channel Pb:

Component after inverse scrambling among received signal components of physical channel Pc:

According to the above equation, when the scrambling codes are the same as in Equations 4 and 5, the scrambling code at the time of reverse scrambling Indicates that only the channel code components remain. In this case, if the chip synchronization between the physical channel Pa and the physical channel Pb is correct, there is no interference due to the orthogonality between the codes.

Thus, as shown in FIG. 5, physical channels having the same scrambling code are transmitted in synchronization with chip synchronization.

On the other hand, as shown in Equation 6 above, the interfering physical channels having different scrambling codes from the physical channels to be received are not lost even if the scrambling code is reversely scrambled by the base station receiver.

In this case, since the received signal of the interfering physical channel includes not only a channel code but also a scrambling code and an inverse scrambling code component, even if chip synchronization is correct, there is no orthogonality between the physical channels.

The amount of interference between two non-orthogonal physical channels depends on how much the difference in chip transmission start point between the two physical channels is sent. In general, the greater the difference between the chip transmission start points, the less the amount of interference between physical channels. Difference of Starting Points of Chip Transmission Between Two Physical Channels ( Is 0, the chip synchronization is correct, and in this case, the amount of interference between the two physical channels is the largest.

0 to half chip interval ( While increasing to the value of), the interference between the two physical channels is reduced. However, the difference between the starting point of chip transmission is half chip period ( Above), the time difference from the next chip is reduced, so the difference between the actual starting point of chip transmission is rather reduced, and the amount of interference end from It is larger while increasing to the value of. end When the chip is synchronized again The amount of interference is largest, as in the case of = 0. In other words, The amount of interference between two physical channels Has a cycle, Has a maximum value when = 0, If is the minimum.

The following demonstrates the above example. Difference in Chip Synchronization Between Two Physical Channels The power of the interference between two physical channels Proportional to Expressing such a relationship is shown in Equation 7 below.

Where P (t) is a pulse shape function, The phosphorus interval has an arbitrary value and the other interval has a value of zero. In other words, Denotes the length of the interval where the pulse shape function has a meaningful value.

To obtain a numerical example for Equation 7, the pulse shape function is a root-raised cosine (RRC) function and the parameter ( Consider the case of = 0.22. Root-raised Cosine (RRC) function May be represented by Equation 9 below.

Equation 8 above is Is defined for −∞ <t <∞, which is not suitable for practical implementation. To complement this P (t) which is time-limited is used, and p (t) is expressed by Equation 9 below.

According to Equation 9 above, Represents the length of the time interval for which the pulse shape function has a meaningful value. If the value of d is infinity, Equation 9 has the same value as Equation 8. Therefore, Equation 9 may be referred to as a generalized equation of Equation 8.

According to the first embodiment of the present invention as described above, = 0 is the largest interference between two non-orthogonal physical channels, In this case, it can be seen that the interference between the two physical channels having no orthogonality is minimal. This is a parameter You can achieve the same result by setting to different values and by using different pulse shape functions.

Based on these results, it is possible to reduce the interference between each other at the time of reception than to synchronize the chip synchronization when transmitting without transmitting chip synchronization between physical channels having no orthogonality. In addition, when a pulse filter is implemented as a digital filter, Since the sampling is performed at a period, if the time shift is performed in units of a sampling period or an integer multiple of the sampling period between the non-orthogonal physical channels, hardware can be simply implemented.

In addition, by applying a time shift between respective heterogeneous signals during signal transmission, a correlation value of interference between heterogeneous signals may be reduced in a pulse-shaped filter during reception.

Therefore, since the scrambling code does not have orthogonality between different physical channels, it is possible to reduce interference between the base stations and the receivers at the base station receiver rather than sending the chip synchronizer when transmitting the scrambling code.

In addition, the scrambling code divides the difference of the chip transmission start points between different physical channels by ) Can minimize interference.

In addition, even when the number of scrambling codes used in one base station is three or more, the scrambling code does not have a difference in the starting point of chip transmission between physical channels having the same scrambling code, and the scrambling code has a difference in the starting point of the chip transmission only between other physical channels. Make a difference. At this time, the difference in the optimal chip transmission start point is such that the total sum of the interference power between all physical channels is minimized.

The sum of interference powers of all physical channels of the primary scrambling code and the M secondary scrambling codes is expressed by Equation 10 below.

Where abs (x) is the absolute value of x, Is a transmission time delay of the primary scrambling code, which is 0. When n is equal to m, the same scrambling code is used. In this case, since there is no interference due to the orthogonality of the channel code, it is excluded from addition of Equation 10. Is the transmission time delay of the m th secondary scrambling code.

Here, assuming that importance and transmission power of physical channels scrambled with each scrambling code are the same, a case in which three scrambling codes are used in one base station will be described as an example.

Difference in the Optimal Chip Transfer Points of Physical Channels Scrambled with the Three Scrambling Codes Is a value for minimizing S when M = 2 in Equation 10 above.

Therefore, when using the RRC pulse shape function of Equation 9, Becomes

In addition, another example of using three scrambling codes in one base station, In a state of Is determined by referring to Equation 10. To minimize As a matter of determining to be.

By applying the same method as described above, even when four or more scrambling codes are used in one base station, the difference between the chip transmission start points of each scrambling code can be obtained.

Hereinafter, the configuration and operation according to the second preferred embodiment of the present invention will be described with reference to the accompanying drawings.

Second embodiment

However, although the first embodiment of the present invention describes that the scrambling code sets the transmission time delay for each of the same physical channels, it does not provide a clear specification on how to actually set the transmission time delay. In the radio access system of IMT-2000, this transmission time delay should be set in advance. The reason is that the receiver of the terminal performs the reception time synchronization setting using the synchronization channel. In addition, the primary scrambling code does not set the reception time synchronization for the primary scrambling code separately on the assumption that the transmission time of the synchronization channel and the transmission time are the same.

Therefore, the transmission time delay of the secondary scrambling code based on the transmission time of the primary scrambling code, If, is not set in advance, reception time synchronization must be obtained for each secondary scrambling code. That is, the transmission time delay of the secondary scrambling code, , Is set in advance so that the base station and the terminal should know this value.

In the second embodiment of the present invention, the transmission time delay of the physical channel of each scrambling code is set in the IMT-2000 wireless system. The most important thing in determining the transmission time delay of each scrambling code is to minimize the interference caused by other physical channels at the time of reception. That is the performance of the system. The second is the simplicity of the actual hardware to implement the time delay. The third is to set the transmission time delay in accordance with the operation of the scrambling code in the system.

In Fig. 4, the transmission time delay is implemented by using time delays 41 and 42. These time delays 41 and 42 are implemented by digital circuits. In other words, , m = 1, 2, ..., M, have discrete values that are not continuous values from 0 to Tc. If the value of this discrete value is a multiple of the sampling period, that is, the inverse of the sampling rate, there is no additional complexity in hardware implementation. On the other hand, if it is smaller than the sampling cycle, a circuit is needed to divide the sampling cycle again. Therefore, in terms of hardware simplicity, it is preferable that the transmission time delay is a multiple of the sampling period.

This sampling period is typically a chip interval, 1/2 value of Tc, 1/4 value, 1/8 value, etc., depending on the performance required by the system and the technology employed in the implementation. However, no matter how long the sampling period is, this value cannot be greater than half the chip interval. That is, it is assumed that 1/2 of the chip period (Tc / 2), which is the largest value of the sampling period, The simplest case is hardware, where, m = 1, 2, ..., M, is set to zero or half the chip period (Tc / 2).

In addition, there is almost no difference in performance as compared with the case where the value of the transmission time delay is not limited to 0 or Tc / 2. This can be known by calculating the sum of interferences of Equation 10 for the following three cases.

In the first case, there is no transmission time delay. In other words, = 0, m = 1, 2, ..., M,

In the second case, the transmission time delay , Is 0 or Tc / 2. This is a case where there is no additional burden in hardware as described earlier.

In the third case, we demonstrate the transmission time, , Has a multiple of Tc / n. In this case, the value of n has an infinity when it has a continuous value among the values between 0 and Tc. However, as the value of n increases, the time for calculating the value of S in Equation 10 increases exponentially with respect to all possible differences in transmission time. In the present invention, n = 100 was used.

The transmission time delay for minimizing the sum total of the interferences in Equation 10 for the above three cases, , m = 1, 2, ..., M, and the sum of interferences, S, are obtained in Table 1 below.

In Table 1, the sum of interferences in three cases is defined as S1, S2, and S3, respectively. As can be seen from Table 1, it can be seen that the total sum of interferences is reduced by 6.5% or 10.9% compared to the case where the transmission time delay (second and third cases) does not have the transmission time delay. However, comparing the case where the transmission time delay has a limited value (second case) and the case where no limit (third case) is used, the difference in the total sum of interferences is less than 1%. This can be seen from Table 2.

As shown in Table 2 above, even if it limits the value that the transmission time delay can have, the performance degradation caused by this is very small. In addition, since the number M of secondary physical channels used in the system is not fixed, it is impossible to change the transmission time delay according to the value of M that changes. Therefore, in the present invention, the transmission time delay of the physical channel of each scrambling code of the radio access system of IMT-2000, , m = 1, 2, ..., M, is set to have a value of 0 or a value of Tc / 2.

Hereinafter, a method of setting a difference in transmission time of each physical channel will be described in consideration of the operation of the system.

As described in the description of the present invention, if the reception power of the physical channel of each scrambling code is the same in all the terminals, the transmission time delay at that time is as follows. = 0.5Tc, if m is even It is optimal to set = 0. This means that the interference of the physical channel is minimized so that the strength of the reception power corresponding to the transmission time delay value 0 and the transmission power delay of the half chip are the same. This case is defined as situation 1, and the transmission time delay at this time is shown in Table 3 below.

In this case, in a real system, a synchronization channel exists in addition to the scrambled physical channel. Since this channel is transmitted at the same time as the primary scrambling code, the strength of the reception power having a transmission time delay value of zero is greater than that of other transmission time delays. In general, when the power of the physical channel of each scrambling code is defined as P and the power of the synchronization channel is defined as K, the relationship of P> K is established. Even in this case, it is preferable that the terminal sets the transmission time delay such that the strength of the reception power corresponding to the value 0 of the transmission time delay is the same as the strength of the reception power corresponding to the half chip. That is, when newly setting the transmission time delay of the first secondary scrambling code, the transmission time delay of the primary scrambling code is already set to 0, and the reception power corresponding to the transmission time delay of 0 is P + K, The reception power corresponding to the half-chip interval of the transmission time delay is zero. Therefore, the transmission time delay of the first primary scrambling code is half chip interval. When setting the transmission time delay of the second secondary scrambling code, the reception power corresponding to the transmission time delay 0 is P + K, and the reception power corresponding to the transmission time delay of the half chip period is P, so that the second secondary scrambling code The transmission time delay is set to half chip. When setting the transmission time delay of the third secondary scrambling code, the reception power corresponding to the transmission time delay 0 is P + K, and the reception power corresponding to the half time interval is 2P. The transmission time delay is set to zero. Using this method, it is possible to set the transmission time delay of the fourth or more secondary scrambling codes. Thus, situation 2 is a case where the strength of the received power corresponding to the transmission time delay of the primary scrambling code is large, and the transmission time delay of the secondary scrambling code at this time is described in Table 3. This situation 2 has an advantage that the performance of the primary scrambling code is slightly improved compared to the situation 1. That is, it is preferable to use situation 2 when the physical channel or sync channel of the primary scrambling code is high, and use situation 1 otherwise.

Until now, it has been assumed that the reception power of the physical channel of each scrambling code is the same in all terminals. However, if the antenna of the base station has a directivity and the directivity of the transmission power of a specific region of the entire cell region for each scrambling code is different, the reception power of the physical channel may be different for each scrambling code received by each terminal receiver. In other words, it is assumed that the physical channel of the primary scrambling code is transmitted with the same power for all cell regions in the base station antenna. And, suppose that the physical channels of several secondary scrambling codes are transmitted with a large power to a specific part of a cell in a base station antenna. Referring to FIG. 6, it is assumed that a large amount of power is transmitted to the first scrambling code to the A region, the second scrambling code to the B region, and the third scrambling code to the C region. If there is a small probability that such areas A, B, and C overlap, the terminal present in each of areas A, B, and C receives only the physical channel of the primary scrambling code and the physical channel of one corresponding secondary scrambling code. Will be. If this case is defined as situation 3, as shown in Table 3, the transmission time delay of the secondary physical channel in situation 3 may have a half chip interval to maximize performance.

As described above, when the transmission time delay of the physical channel of each scrambling code is previously set for each scrambling code so that the base station and the terminal can be known, it is not necessary to separately transmit a signal for the transmission time delay from the base station to the terminal.

The three situations described in the above table were performed under the assumption that after using all the physical channels of the m th secondary scrambling code, the physical channels of the (m + 1) second secondary scrambling code must be sequentially used.

However, there may be a situation in which it is not necessary to follow this order from the system point of view, and the present invention will be described on the assumption of situation 4. After the base station has used all of the physical channels of the mth secondary scrambling code, the base station does not use the physical channel of the scrambling code of the next m + 1th physical channel, but has a transmission time delay among the secondary scrambling codes not yet used. The physical channel of the scrambling code may be used. Even in this case, the transmission time delay of the physical channel of each scrambling code is preset for each scrambling code so as to be known to the base station and the terminal, respectively. Since the scrambling code information is transmitted to the terminal separately, the transmission time from the base station to the terminal at this time The signal for the delay does not have to be transmitted.

As described above, when the scrambling code is operated as described in Situation 4, as shown in FIG. 7, two secondary scrambling codes are uniformly transmitted over the entire cell area in the antenna of the base station and another two secondary scrambling codes are provided. There is an advantage that can be appropriately prepared even in the situation where the antenna of the base station is transmitted with a directivity for each cell area.

First, for the two secondary scrambling codes transmitted to the entire cell region, the first and third scrambling codes having the half-chip transmission time delay are used in the situation 4 of Table 4. In addition, the second and fourth scrambling codes having no transmission time delay are used for two secondary scrambling codes transmitted with a directivity per cell region.

In this case, in the cell region with the scrambling code transmitted with directivity and the region without it, the strength of the reception power corresponding to 0 and the half-chip interval of the transmission time delay in the terminal receiver is attained to achieve optimum performance. have. And, since each transmission time delay of the secondary scrambling code uses a preset value, it is not necessary to transmit separate information from the base station to the terminal.

When the operation status of each scrambling code is complicated at the base station, the transmission time delay for each scrambling code may be separately transmitted from the base station to the terminal. In this embodiment, the information of the transmission time delay is delayed and 1 of the half chip delay. Can be expressed in bits. In case of separately transmitting the transmission time delay, the time for checking the transmission delay can be reduced, thereby minimizing the burden on this.

According to the present invention described above, the base station manages the number of physical channels assigned to it and the number of channel codes to selectively use the scrambling code when the number of physical channels of the base station is greater than the number of channel codes, and transmits If the scrambling codes used between physical channels are identical, chip synchronization is transmitted. If not, the scrambling codes are delayed and transmitted with a smaller value than the chip interval for each physical channel.

In addition, in setting the transmission time delay of the physical channel for each scrambling code, even if the value of the transmission time delay is 0 or one of the half chip intervals, the object of the present invention is sufficiently achieved, and the hardware can be easily implemented.

In addition, in setting the transmission time delay of each secondary scrambling code, it is desirable to set the transmission time delay in the receiver of the terminal so that the value of the received power corresponding to 0 and the half chip interval is equal in terms of system performance.

In addition, when the received power values corresponding to the two transmission time delays boil, the value of the received power having the transmission time delay 0 is reduced, so that the performance of the physical channel signal or the sync channel signal of the relatively important primary scrambling code is reduced. To improve.

Claims (4)

In a CDMA wireless communication system in which a plurality of scrambling codes are allocated to a group of communication channels that can be used in a base station or a cell, and the channel groups are assigned different channel codes, A specific base station manages the number of physical channels assigned to it and the number of channel codes so as to selectively use the scrambling code when the number of physical channels of the base station is larger than the number of channel codes, and the scrambling used between physical channels to be transmitted. If the codes are the same, the chip synchronization is transmitted according to the other, if not the transmission method of the physical channels in a wireless communication system, characterized in that the scrambling code is transmitted by delaying the chip synchronization for each physical channel. 2. The method of claim 1, wherein when using at least two scrambling codes, the base station corresponds to each time delay of all terminal receivers in the cell area when the plurality of time delay values are selected to be one of two values of 0 and half chip. How to set the transmission time of the physical channels in the wireless communication system, characterized in that the time delay so that the sum of the received power to boil 3. The method of claim 2, wherein when the sum of the received powers corresponding to the time delays for each terminal boils, the base station has less power than the value of time delay 0 corresponding to the primary scrambling code among the scrambling codes. The transmission time setting method of the physical channels in the wireless communication system, characterized in that for setting the transmission delay time to be received. The transmission time of the physical channels in the wireless communication system according to claim 1, wherein when the time delay of the physical channel transmitted from the base station is set, the base station informs the terminal station of a time delay value through a separate signal. How to set up.