KR20020069317A - A timing adaptaion method for USTS in asynchronous IMT-2000 system - Google Patents

Abstract

The present invention relates to a timing adaptation method for reverse synchronization transmission in a next generation asynchronous mobile communication system for stably applying a reverse synchronization transmission scheme (USTS) to an asynchronous IMT-2000 system. The delay time is measured at a period of 100 ms, the time alignment bit (TAB) information for the transmission timing update at the terminal is determined based on the measured delay time, and the determined TAB information is repeated at a 20 ms period for the measurement period 100 ms. A timing adaptation method at the base station for the USTS, which is sent or encoded and transmitted to the corresponding terminal; And receiving or decoding TAB information transmitted from the base station to determine or decode statistical values of the received information every 100 ms, and determine TAB information, based on the determined 2-bit TAB information for a 200 ms minimum transmission timing update period. And a timing adaptation method at the terminal for the USTS to adjust the transmission timing of the.

Description

A timing adaptation method for USTS in asynchronous IMT-2000 system}

The present invention relates to a timing adaptation method for backward synchronous transmission in a next generation asynchronous mobile communication system. A timing adaptation method for reverse synchronous transmission in a next generation asynchronous mobile communication system that secures operation.

In general, the uplink synchronous transmission scheme (hereinafter referred to as USTS) is used to maximize orthogonality between uplink channels according to a reference time managed by a corresponding base station for transmission times of a plurality of mobile terminals in a base station cell. As a more detailed description, as follows.

The mobile station in the base station cell attempts a call connection using a reverse channel, and the base station measures a round trip propagation delay of the signal to obtain a time difference between the reference time and the frame start time of the mobile terminal that attempted the call connection. . Similarly, even when the mobile terminal is called, the base station informs the time difference from the reference time by calculation. By providing this time offset information from the base station to the mobile terminal using the control channel, the mobile terminal adjusts the frame transmission time in the transmission channel at the reference time held by the base station. The time of arrival of the signal from the mobile terminal to the base station is adjusted to the reference time by measuring the continuous time offset, transmitting to the mobile terminal, and adjusting the transmission timing at the mobile terminal even during a call. Other mobile terminals attempting to make a call in the same base station are also informed of the time difference compared to the unique reference time held by the base station in the same manner to adjust the frame reference time to the base time of the base station. At this time, the mobile terminal and the base station use two codes, a scrambling code and a channel code. The channel code is used to distinguish channels between mobile terminals, and the mobile terminals using the same scrambling code are eliminated by the orthogonality of the channel codes.

This USTS is currently being considered in the standardization work for the next generation of asynchronous mobile communication system. As described above, the USTS is based on the reception timing of the base station receiver for the reverse link from the mobile station to the base station. Is a technique for adjusting the time of signal transmission. That is, since mobile terminals irregularly positioned in a single cell have different distances from the corresponding base station, the propagation delay of the signal is also different, and if the orthogonal characteristic of the code is maximized in a code division multiple access (CDMA) system, the transmission capacity It is possible to increase the value, and in consideration of this, the technique applied to the reverse link is USTS. Further adjustment of the data transmission time at each mobile terminal by the propagation delay for the reverse link enables synchronization of the timing at which the signal is received at the base station receiver, thus maximizing the orthogonality of the code.

Currently, the structure of a downlink dedicated channel used in an asynchronous IMT-2000 system is as shown in FIG. 1, and as shown in the figure, a system frame number for each radio frame in a dedicated channel of the IMT-2000 system. (System Frame Number: SFN) (Frame n-1, Frame n, Frame n + 1, Frame n + 2) is repeated in units of 0 to 4096, and correspondingly, Connection Frame Nember: CFN ) Is repeated in 256 units, and the interval between each SFN (or CFN), that is, the length of one radio frame is 10ms, and is synchronized between the network and the terminal based on the SFN.

That is, since a length of one radio frame is 10ms in the forward (or downlink) dedicated channel (DPCH) and consists of 15 subslots (slot # 0 to slot # 14), this asynchronous IMT In order to apply the USTS scheme in a dedicated channel structure of a -2000 system, time alignment bit (TAB) information as a time offset information for timing adaptation of the USTS is applied every 20ms (ie, one per two radio frames). In addition, instead of transmitting power control (TPC) bits carried in the corresponding radio frame, it is punched and transmitted.

The mobile terminal receiving the TAB information maintains synchronization with the reverse direction by performing timing adaptation based on the received TAB information. For example, if the TAB bit is "0", the uplink transmission from the mobile terminal is delayed by 1/4 chip, and if the TAB bit is "1", the reverse link transmission is 1/0. 4 chips ahead to transmit. This procedure is called timing tracking. When the initial timing setup process is completed, the network system and the mobile station applying the USTS perform timing tracking on subsequent transmissions to maintain backward synchronization continuously.

However, the above-described USTS application method has a problem that the overhead of the base station is increased due to the delay of the received signal in the 20 ms unit in order to transmit the TAB in 20 ms units. Since 1 bit TAB information is repeatedly transmitted in the form of 2 symbols or 4 symbols, there is a problem in that the probability of error occurrence is very high and the system cannot obtain a gain in the USTS for the corresponding mobile terminal.

In addition, in consideration of a correlation between a user's movement speed and a propagation speed through a vehicle in an asynchronous IMT-2000 system environment, a condition for maintaining a timing update period of a mobile terminal to be at least 200 ms must be satisfied. The current update period is 20ms, which does not satisfy the above condition at all.

Also, when determining the TAB bit at the base station, even if the synchronization is correct, the TAB bit must be determined as one of '0' or '1', and correspondingly, one of the delay or advancement of the reverse link transmission time in the mobile terminal is correspondingly determined. Since must be performed, there was a problem that does not get a more reliable USTS gain.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object thereof is to reduce overhead caused by delay time measurement at a base station, improve transmission efficiency of TAB information, and improve a timing update period of a mobile terminal. The USTS scheme is applied to the asynchronous IMT-2000 system stably by satisfying the requirements of the asynchronous IMT-2000 system completely. The purpose of the present invention is to provide a timing adaptation method for backward synchronous transmission in a next generation asynchronous mobile communication system designed to improve system performance.

1 is a configuration diagram of a downlink dedicated channel used in an asynchronous IMT-2000 system.

2 is a diagram illustrating a timing adaptation method for reverse synchronous transmission in a next generation asynchronous mobile communication system according to an embodiment of the present invention;

3 is a diagram illustrating a timing adaptation method for reverse synchronous transmission in a next generation asynchronous mobile communication system according to another embodiment of the present invention.

In order to achieve the above object, a timing adaptation method for reverse synchronization transmission in a base station of a next-generation asynchronous mobile communication system according to the present invention includes a delay time of a signal transmitted and received from a terminal than a minimum transmission timing update period in the terminal. A first step of measuring at small intervals; Determining a time alignment bit (TAB) information for the transmission timing update based on the measured delay time; And a third step of transmitting the determined time alignment bit information to the terminal in a period less than the measurement period during the measurement period.

In the second step, when the difference in the measured delay time with respect to the reference time is within a preset allowable range, the time alignment bit information is determined to be a bit value opposite to the immediately determined time alignment bit information value.

In the third step, for example, the determined time alignment bit information may be repeatedly transmitted for each transmission period during the measurement period.In another example, the time alignment bit information may be coded by using an appropriate coding method and then coded. Each configuration information of a codeword is allocated to a corresponding field in each transmission period during the measurement period and transmitted.

The minimum transmission timing update period is 200ms, the measurement period is 100ms, and the transmission period is set to 20ms or 40ms.

In order to achieve the above object, a timing adaptation method for reverse synchronization transmission in a terminal of a next generation asynchronous mobile communication system according to the present invention includes one or more time alignment bit information transmitted from a base station at a period smaller than a minimum transmission timing update period. A first step of receiving and determining one time alignment bit based on the received information; A second step of determining whether an update time point according to the minimum transmission timing update period has been reached during the repetition of the first step; And a third step of adjusting the transmission timing of the corresponding frame based on the plurality of time alignment bits determined by the repetition of the first step when determining the arrival.

In the first step, for example, the one time alignment bit may be determined by applying statistics on the received time alignment bit information, and in another example, the received time alignment bit information may be appropriately determined corresponding to coding at the base station. Decoded by the decoding method to determine the one time alignment bit.

In the third step, even when an update time point corresponding to the minimum transmission timing update period is reached, when the currently determined time alignment bit and the previously determined one time alignment bit have different values, the next one time Delay the decision on the transmission timing adjustment to the alignment bit determination time.

The minimum transmission timing update period is 200 ms, the determination period of the one time alignment bit is 100 ms, and each reception interval of the one or more time alignment bit information is set to 20 ms or 40 ms.

In addition, the number of the one or more time alignment bit information that should be received during a period less than the minimum transmission timing update period is calculated based on an internal count and SFN value, and the time alignment bit determined in the first step is determined by a shift register. Maintain and manage.

In order to achieve the above object, in the next generation asynchronous mobile communication system according to the present invention, a timing adaptation method for reverse synchronization transmission may include a round trip delay time of a signal transmitted and received from a terminal based on a preset reference time. Measuring the minimum transmission timing update period at equal intervals, and determining the time alignment bit information for the transmission timing update based on the measured round trip delay time, and the determined time alignment. A timing adaptation method for reverse synchronous transmission in a base station, comprising three steps of repeatedly or encoding bit information and transmitting it to the terminal in a period smaller than the measurement period during the measurement period; And receiving at least one time alignment bit information transmitted from the base station at a constant period in which the minimum transmission timing update period is equally divided, and determining or decoding one time alignment bit by calculating or decoding statistics of the received information. And, during the repetition of the four steps, determining whether an update time point according to the minimum transmission timing update period has been reached; and when determining the arrival, based on the plurality of time alignment bits determined by performing the repetition of the four steps. And a timing adaptation method for reverse synchronization transmission in a terminal having six steps of adjusting a transmission timing of a corresponding frame.

In the second step, when the difference between the measured round trip delay time with respect to the reference time is within a preset allowable range, the time alignment bit information may be determined as a bit value opposite to the previously determined time alignment bit information value. Correspondingly, in step 6, even when an update time point corresponding to the minimum transmission timing update period is reached, when the currently determined time alignment bit and the immediately determined one time alignment bit have opposite values, Delay the decision on the transmission timing adjustment to one time alignment bit decision point.

In step 4, the number of one or more time alignment bit informations to be received during the predetermined period in which the minimum transmission timing update period is equalized is calculated based on an internal count and an SFN value, and the determined time alignment bit is Maintained and managed by a 2-bit shift resist.

In addition, the minimum transmission timing update period is 200 ms, and the constant period in which the minimum transmission timing update period is equally divided is 100 ms, and each reception of the one or more time alignment bit information in the third transmission period and the fourth step is performed. The interval should be set to either 20ms or 40ms.

Hereinafter, a timing adaptation method for reverse synchronous transmission in a next generation asynchronous mobile communication system according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In order to reduce the transmission error probability of the TAB bit among the existing problems, a method of repeatedly transmitting the TAB bit from the base station or a method of increasing the transmission power for the TAB bit may be used. Among these methods, the repetitive transmission method can minimize the impact on the existing system.

However, in consideration of the requirement that the transmission timing update period of the mobile terminal be 200 ms or more, the timing change by the TAB occurs after a certain time, so that an appropriate channel coding scheme is not transmitted through simple repetition of code. Through code wordization through the TAB information bits for a certain period can be used.

In the channel coding scheme, an encoder for coding TAB information bits must be added to the base station, and a channel coding delay and a decoding delay in a mobile terminal may occur. However, when the delay time is very short, reliability of the TAB information may be reduced. It can be improved and is very effective.

First of all, it is necessary to determine the transmission period of TAB information used in the USTS. Assuming that a method of determining a frame in which the TAB is to be transmitted is based on the SFN value as in the present case, the minimum transmission timing update period in the mobile terminal is determined. In consideration of this, it is preferable to set the transmission period of the TAB to 20 ms or 40 ms. In addition, it is preferable to perform the transmission timing update in the mobile terminal as 200 ms, not the 200 ms unit, when the timing change is necessary later.

In the current asynchronous IMT-2000 standard, since the measurement report interval for the dedicated channel in the base station is 100 ms, in order to prevent additional changes to the base station, the delay measurement for the received signal should be performed in units of 100 ms.

In the present invention, there is no limitation on the coding method of the TAB information, and only the TAB transmission method and the timing update method in the terminal are proposed for the case where the transmission period of the TAB information is 20 ms and 40 ms. Each case will be described in detail.

FIG. 2 is a diagram illustrating a timing adaptation method for backward synchronous transmission in a next generation asynchronous mobile communication system according to an embodiment of the present invention, in which part (A) measures TAB information by measuring a delay time at a base station. (B) shows the configuration of a DL DPCH Radio Frame of the downlink dedicated channel, and (C) shows the radio of the uplink dedicated channel corresponding to (B). A configuration of a frame (UP DPCH Radio Frame) is shown, (D) shows the process of extracting and determining the TAB in the terminal, and (E) shows the transmission timing update process in the terminal.

In this embodiment, the reception signal delay time measurement period for determining the TAB information at the base station is 100ms, and the transmission period of the TAB information for repeatedly transmitting one TAB information determined based on the measurement for the measurement period 100ms. Is 20ms. In addition, the reception period of the TAB information at the terminal is 20ms corresponding to the transmission period at the base station, and the TAB determination period for determining one TAB based on the reception is 100ms, and the transmission timing is determined based on the determination. The minimum transmission timing update period for updating is 200 ms.

First, the base station equipment uses CFN = N-1, CFN = N + 9, CFN = N + 19, and CFN in 100ms periods, that is, 10 radio frame periods, for a signal received from a mobile terminal as shown in FIG. Delay measurement is performed based on the preset reference time at = N + 29, ..., where the minimum resolution of the measurement is 1/16 chip, and the mobile terminal maintains its transmission timing update time. do.

Since the transmission period of the TAB at the base station is 20 ms (that is, two radio frame lengths), the mobile station determines whether the remaining value divided by 2 by the SFN value of the received radio frame is '0' or '1' (that is, the SFN value). The even or odd number) determines whether the frame includes the TAB, and the base station transmits the frame accordingly.

For example, when the TAB based on the delay measurement at CFN = N-1 is determined to be '0' as shown in (A) of FIG. 2, the base station has five radio frames having even SFN values for the next 100ms (B). CFN = N, CFN = N + 2, ..., CFN = N + 8: Here, N = 0) is repeatedly transmitted with the determined TAB information, and correspondingly, the mobile terminal receives the SFN value of the received radio frame. If the remaining value divided by 2 is '0', it is determined that TAB information is included in the corresponding frame.

The timing update decision in the mobile terminal is based on the monitored value for 200 ms, and the basic TAB information value is determined as the value received for 100 ms. That is, as shown in FIG. 2 (C) (D), the mobile terminal determines whether the TAB information value is 0 or 1 based on a 5-bit TAB value received from an even number of radio frames during a 100 ms sub-interval. In this case, the simplest method is a statistical technique, which determines a TAB value from a plurality of bits of zero or one of five bits. Therefore, if the TAB information sent by repeating 5 times in 20 ms periods, one TAB bit determined by measuring the 100 ms period from the base station is '00000', and correspondingly, if the TAB information received from the terminal for 100 ms is '00001', even two bits Even if there is an error in the following (the last one bit), at the decision point (a) of (D), since the value of 0 is composed of many values in '00001', the TAB value is finally determined as '0'. This greatly reduces the probability of error.

Basically, since the minimum time value for timing update in the mobile terminal is 200ms, as shown in (E) of FIG. 2, the timing update is determined based on the 2-bit TAB information values acquired in two 100-ms subsections. For this purpose, the mobile terminal applies a 2 bit shift resist. The operation according to the TAB information value of each sub-interval used by the mobile terminal to determine whether to update the timing is shown in Table 1 below.

TABLE 1

TAB pattern Action Before After 0 0 Delay timing by 1/4 chip 0 One Reserved timing decision for 100ms One 0 Reserved timing decision for 100ms One One Pull Tim by 1/4 Chip

If the interval between the previous transmission timing update time and the current transmission timing update time is less than 200 ms, the mobile terminal defers the timing update to the next sub-interval, and if the interval is larger than 200 ms, it is based on the TAB value during the last 200 ms interval. The timing update is then determined. That is, the TAB value for each sub-section for determining the transmission timing adjustment operates in the same manner as the 2-bit shift register, and the operation thereof is shown in Table 1 above.

More specifically, the transmission timing update process in the mobile terminal will be described below.

In the decision point (a) of FIG. 2D, since the value of the update timer of the mobile terminal (that is, the time from the previous update time to the present) is smaller than 200 ms regardless of the value of the TAB information, the transmission time Updates to do not need to be considered. At decision point (b), the condition that the value of the update timer should be 200 ms or more is satisfied, so it is determined whether to adjust the transmission timing. However, since the TAB information received during the 100 ms sub-interval until reaching the determination point (b) is determined to be '1', the state value of the TAB resist becomes '01' as shown in FIG. According to [Table 1], the transmission timing adjustment of the mobile terminal is delayed after 100 ms, which is the next sub period.

At decision point (c), the status value of the TAB resist reflecting the condition that the value of the update timer should be 200 ms or more and reflecting the TAB information received during the 100 ms sub-interval until reaching the determination point (c) is shown in FIG. As shown in (E), the transmission timing of the mobile terminal is advanced by 1/4 chip. At this point, the value of the update timer is reset and the update timing is maintained.

If the current mobile terminal maintains the correct transmission timing value, the base station should be able to instruct the mobile terminal to maintain the transmission timing. For this purpose, the base station moves by transmitting a value opposite to the value transmitted during the previous sub-interval. The timing update period in the terminal is delayed by 100 ms. This is to prevent unnecessary timing update in the mobile terminal and to be able to quickly adapt when timing update is necessary.

That is, even if the update period of at least 200 ms or more is satisfied as in decision point (b), if the TAB resist value is '01' (or '10'), the reason for causing the transmission timing adjustment to be deferred to the next sub-interval is currently reversed. This is because the synchronous transmission is performed. For this reason, for example, in the base station, if the measured delay time is within a preset tolerance range of ± 1/4 chip range (or ± 1/8 chip range), The TAB is determined to be transmitted with a bit value opposite to that of the previously determined TAB.

For example, when the base station measures the delay time of the signal received at CFN = N + 9 in FIG. 2A, and the delay time is within the ± 1/4 chip range, the base station determines '0' immediately before determining the TAB. It is determined by a value of '1' opposite to and repeatedly transmitted, so that the mobile terminal operates as in decision point (b).

FIG. 3 is a diagram illustrating a timing adaptation method for reverse synchronous transmission in a next generation asynchronous mobile communication system according to another embodiment of the present invention. In FIG. 3, part (A) shows TAB information by measuring a delay time at a base station. And (B) shows the configuration of a DL DPCH Radio Frame of the downlink dedicated channel, and (C) shows (B) the process of encoding the determined TAB information. ) Shows a configuration of an uplink dedicated radio frame (UP DPCH Radio Frame) corresponding to), (D) shows a process of deciding and extracting a TAB in the terminal, and (E) shows The transmission timing update process in FIG.

The embodiment of FIG. 3 is different from the embodiment of FIG. 2 in that encoding is used instead of TAB repetitive transmission at the base station, and decoding is used instead of statistical processing of TAB information at the terminal. same.

That is, the base station coded the TAB information using an encoder having excellent error rate characteristics, and allocated each of the information of the code word (S1, S2, ..., S5) to five radio frames for transmission. In response, the mobile terminal decodes the received code word to determine the TAB.

The TAB transmission method in the base station and the timing update method in the terminal for the case where the transmission period of the TAB information is 20ms has been described above with reference to FIGS. 2 and 3, and as another embodiment of the present invention, Explain about 40ms.

The base station performs a delay measurement on a signal received from the mobile terminal every 100ms, and the mobile terminal maintains its transmission timing update time, which is the same as in the embodiment described above.

In this embodiment, since the transmission period of the TAB is 40 ms, the TAB information received during each 100 ms sub-interval is 2 bits or 3 bits. Therefore, the mobile terminal should be able to calculate the number of TAB information to be received during each sub-interval. That is, the SFN value divided by 4 identifies whether the frame includes TAB information, and whether the TAB information corresponds to 2 bits or 3 bits using an internal count value from the initial setting. It should be determined, and the base station transmits accordingly. That is, the base station should alternately use an encoder having a 2-bit output and a 3-bit encode according to the situation, and the decoding in the mobile terminal should be performed in the same way. Other operations are the same as the case where the transmission period of the TAB information described above with reference to FIGS. 2 and 3 is 20 ms.

As described in detail above, according to the timing adaptation method for reverse synchronous transmission in the next generation asynchronous mobile communication system according to the present invention, since the measurement cycle for the existing dedicated channel is used as it is, the delay time is measured according to the delay time measurement. It eliminates the overhead and improves the transmission efficiency of the TAB information by using an iterative transmission or a coding transmission method when transmitting the TAB information. In addition, the timing update period of the mobile terminal completely satisfies the conditions required in the communication environment of the asynchronous IMT-2000 system, and when the synchronization is obtained at the base station, the timing update at the mobile terminal is suspended so that unnecessary timing update is excluded. Improve reliability

Accordingly, the present invention creates the effect of maximally improving the performance of the system by stably applying the USTS scheme to the next generation asynchronous mobile communication system such as the asynchronous IMT-2000 system without changing the system.

Claims (21)

A method for applying a reverse synchronous transmission scheme to an asynchronous mobile communication system, A first step of measuring a delay time of a signal transmitted and received from a terminal at a period smaller than a minimum transmission timing update period at the terminal based on a preset reference time; Determining time alignment bit information for the transmission timing update based on the measured delay time; And And transmitting the determined time alignment bit information to the terminal in a period less than the measurement period during the measurement period. The method of claim 1, In the second step, when the difference of the measured delay time with respect to the reference time is within a preset allowable range, the time alignment bit information is determined as a bit value opposite to the immediately determined time alignment bit information value. A timing adaptation method for reverse synchronous transmission in a base station of a next generation asynchronous mobile communication system. The method of claim 2, The allowable range is one of the range of ± 1/4 chip or ± 1/8 chip range, timing adaptation method for the reverse synchronization transmission in the base station of the next generation asynchronous mobile communication system. The method of claim 1, The third step, the timing adaptation method for the reverse synchronization transmission in the base station of the next generation asynchronous mobile communication system, characterized in that for repeatedly transmitting the determined time alignment bit information for each transmission period during the measurement period. The method of claim 1, In the third step, the time alignment bit information is coded into a codeword, and then each component information of the codeword is divided and transmitted to the corresponding field in each transmission period during the measurement period. A timing adaptation method for reverse synchronous transmission in a base station of a next generation asynchronous mobile communication system. The method according to any one of claims 1, 4 and 5, The minimum transmission timing update period is 200ms, the measurement period is 100ms, the transmission period is 20ms, timing adaptation method for the reverse synchronization transmission in the base station of the next generation asynchronous mobile communication system. The method according to any one of claims 1, 4 and 5, The minimum transmission timing update period is 200ms, the measurement period is 100ms, the transmission period is 40ms, the timing adaptation method for the reverse synchronization transmission in the base station of the next generation asynchronous mobile communication system. A method for applying a reverse synchronous transmission scheme to a next generation asynchronous mobile communication system, Receiving at least one time alignment bit information transmitted from the base station at a period less than the minimum transmission timing update period, and determining one time alignment bit based on the received information; A second step of determining whether an update time point according to the minimum transmission timing update period has been reached during the repetition of the first step; And And a third step of adjusting a transmission timing of a corresponding frame based on a plurality of time alignment bits determined by the repetition of the first step when determining the arrival. Timing adaptation method for synchronous transmission. The method of claim 8, The first step is the timing adaptation method for the reverse synchronization transmission in the terminal of the next generation asynchronous mobile communication system, characterized in that for determining the one time alignment bit by applying the statistics on the received time alignment bit information. The method of claim 8, In the first step, the one time alignment bit is determined by decoding the received time alignment bit information. The timing adaptation method for reverse synchronization transmission in a terminal of a next generation asynchronous mobile communication system. The method of claim 8, In the third step, even when an update time point corresponding to the minimum transmission timing update period is reached, when the currently determined time alignment bit and the previously determined one time alignment bit have different values, the next one time And a delay of the transmission timing adjustment at an alignment bit determination time point. The method of claim 8, The minimum transmission timing update period is 200 ms, the determination period of the one time alignment bit is 100 ms, and each receiving interval of the one or more time alignment bit information is 20 ms. Timing adaptation method for transmission. The method of claim 8, The minimum transmission timing update period is 200 ms, the determination period of the one time alignment bit is 100 ms, and each receiving interval of the one or more time alignment bit information is 40 ms. Timing adaptation method for transmission. The method according to any one of claims 8, 12 and 13, The next generation asynchronous movement, characterized in that the number of the at least one time alignment bit information to be received is calculated based on an internal count and a system frame number (SFN) value during the constant period in which the minimum transmission timing update period is equally divided. A timing adaptation method for reverse synchronous transmission in a terminal of a communication system. The method of claim 8, And the determined time alignment bits are maintained and managed by a shift register. The method of claim 15, And said shift resist is a 2-bit shift resist. The timing adaptation method for reverse synchronous transmission in a terminal of a next generation asynchronous mobile communication system. A method for applying a reverse synchronous transmission scheme to a next generation asynchronous mobile communication system, Step 1 of measuring a delay time of a signal transmitted from the terminal and received at a constant period in which the minimum transmission timing update period in the terminal is equally divided, and based on the measured delay time, time alignment bit information for the transmission timing update 2 steps of determining a; and three steps of repeatedly or encoding the determined time alignment bit information to transmit to the terminal in a period smaller than the measurement period during the measurement period. ; And Receiving one or more time alignment bit information transmitted from the base station at a constant period in which the minimum transmission timing update period is equally divided, and determining or time-decoding one statistical alignment of the received information by determining one time alignment bit. And, during the repetition of the four steps, determining whether an update time point according to the minimum transmission timing update period has been reached; and when determining the arrival, based on the plurality of time alignment bits determined by performing the repetition of the four steps. And a timing adaptation method for reverse synchronous transmission in a terminal having six steps of adjusting a transmission timing of a corresponding frame. The method of claim 17, In the second step, when the difference between the measured round trip delay time with respect to the reference time is within a preset allowable range, the time alignment bit information may be determined as a bit value opposite to the previously determined time alignment bit information value. Correspondingly, in step 6, even when an update time point corresponding to the minimum transmission timing update period is reached, when the currently determined time alignment bit and the immediately determined one time alignment bit have opposite values, And delaying the determination of the transmission timing adjustment by one time alignment bit decision time point. The method of claim 17, The minimum transmission timing update period is 200ms, the constant period in which the minimum transmission timing update period is equally divided is 100ms, and each reception interval of the at least one time alignment bit information in the third transmission period and the fourth step is A timing adaptation method for reverse synchronous transmission in a next generation asynchronous mobile communication system, characterized in that it is either 20ms or 40ms. The method of claim 17 or 19, In step 4, the number of the one or more time alignment bit informations to be received during the predetermined period in which the minimum transmission timing update period is equalized is calculated based on an internal count and a system frame number (SFN) value. A timing adaptation method for reverse synchronous transmission in a next generation asynchronous mobile communication system. The method of claim 17, And in said step 4, said determined time alignment bits are maintained and managed by a 2-bit shift register.