KR100394038B1 - Method for applying USTS to macro cell in W-CDMA system - Google Patents

Abstract

According to the present invention, when applying the backward synchronous transmission scheme (USTS) to a wideband code division multiple access (W-CDMA) system, the time interval between the forward channel reception and the reverse channel transmission at the mobile station is asynchronous regardless of the cell size. The present invention relates to a method for operating reverse channels to USTS while satisfying a range required by the W-CDMA system, and particularly to allow USTS to be optimally applied to a macro cell. Setting a synchronization reference time value Tref for the first step; And a result of adding up the value of the synchronization reference time value Tref and an integer multiple of the repetition period value of the channel code, respectively, as the synchronization reference time value Tref, n for synchronization of the reverse channel for each mobile station in the same cell. Wherein the integer is configured to include a second step of setting based on the time delay value for the transmission and reception signal between the mobile station and the base station, the USTS technology can be applied regardless of the size of the cell, in a large cell The effects of solving the power control delay that may occur when applying the USTS technology or the combination of forward channels during soft handover are created.

Description

A method for applying a wide cell using a backward synchronization transmission method for a wideband code division multiple access system {Method for applying USTS to macro cell in W-CDMA system}

The present invention relates to a method for applying a reverse synchronous transmission scheme for a wideband code division multiple access system in a wide area cell, and more particularly, to provide a backward synchronous transmission scheme (USTS) to a wideband code division multiple access (W-CDMA) system. When applied, regardless of the size of the cell, the time intervals between the forward channel reception and the reverse channel transmission at the mobile station satisfy the range required by the specification of the asynchronous W-CDMA system, and operate the reverse channels in USTS, in particular. The present invention relates to a method for optimally applying USTS to a macro cell.

In a conventional code division multiple access mobile communication network, a call generated between a mobile station and a base station includes a forward channel and a reverse channel. In the case of a forward channel transmitted from a base station to a mobile station, a plurality of channels existing in one base station are synchronized with each other, thereby significantly reducing inter-channel interference during decoding by using an orthogonal code having an orthogonality characteristic between each channel. You can. However, in the case of the reverse channel transmitted from the mobile station to the base station, the mobile station operates in an asynchronous form because the location and the transmission time point of the mobile station are different. As the channel of the mobile station increases, the interference in the reverse direction increases and the capacity is limited.

In case of the reverse direction, the transmission time of the mobile station is adjusted to synchronize the reverse channels, and multiple mobile stations use the same scrambling code, and the division of channels is orthogonal code to minimize the interference between the channels and reduce the capacity. This method is called Uplink Synchronous Transmission Scheme (USTS).

The USTS technique must continuously adjust the transmission time of the reverse channel at the mobile station in order to maintain orthogonality between the reverse channels. In the conventional USTS scheme, a time point at which a reverse channel of a mobile station reaches a base station is determined by one value (Tref) for each cell, and the mobile station adjusts a transmission time point according to the arrival time point. In this method, since the time from the transmission of the forward channel to the reception of the reverse channel is fixed regardless of the size of the cell, when the size of the cell grows, the mobile station receives the forward channel after receiving the forward channel. There is a problem that the time interval may be too large or too small. If the interval between the forward channel reception and the reverse channel transmission is out of the range defined in the asynchronous W-CDMA, there is a problem of power control delay, and the soft channel overcombining the forward channel delay causes additional hardware. There is a problem that is needed.

More specifically described as follows.

In conventional asynchronous W-CDMA, the reverse channels of mobile stations operate asynchronously, and each mobile station distinguishes mobile stations by using its own scrambling code. USTS technology adjusts the time of transmission of a reverse channel at a mobile station for each mobile station so that the base station can receive it at a reference time (this is called time synchronization), and different mobile stations use different channels instead of using a common scrambling code. A code is used to distinguish mobile stations from channels (this is called code synchronization), so that orthogonality can be obtained between channels of various mobile stations.

In the current USTS, one value (Tref) is defined for each cell in order to obtain synchronization of the reverse channel, and the uplink channel transmission time of the mobile station is adjusted according to this Tref value. The Tref value is a value for compensating the propagation delay time from the base station to the mobile station. The time until the base station transmits the forward channel frame to receive the reverse channel frame is constant for all mobile stations with T0 + Tref, where T0 The value is preset to 1024 chips as a nominal default between the forward channel reception and reverse channel transmission times of the mobile station in asynchronous W-CDMA.

The forward channel transmission time τ _{DPCH, n} for each mobile terminal (or mobile station) may have 150 values at 256 chip intervals based on the P-CCPCH frame, which is a common channel of the base station (that is, τ _{DPCH). , n = 256 xn, n =} 0,1,, 149), the point when the uplink channel is reached, but also have a value of 150 to the T0 + Tref + τ _{DPCH, n} from the P-CCPCH frame according to τ _{DPCH, n} value Since the channel code of the reverse channel is repeated in 256 chip units, the reverse channel satisfies the orthogonality when aligned at 256 chip intervals.

In this case, however, there may be a problem when the size of the cell is very large, that is, when the round trip delay exceeds 256 chips. Depending on the position and the Tref value, it is inevitable that the time interval between forward channel reception and reverse channel transmission at the mobile station becomes too large or too small. For example, if the Tref value is set to the maximum unidirectional path delay of the cell, the time difference between the reception of the forward channel frame and the transmission of the reverse channel frame at the mobile station has a value within "T0 ± Tref". If it becomes larger, it is out of the range of "T0 ± 148" which is defined in the specification of the asynchronous W-CDMA system. In this case, the delay of power control becomes large, and there is a problem in adding a new radio link during soft handover, or additional hardware is required to combine the forward channels of two cells.

1 is a view for explaining an example of a problem that may occur when the USTS is applied to a large cell (or a wide area cell) as described above, the base station 110 of the cell (UE) of the corresponding mobile station (UE) With respect to 120, the forward channel signal is transmitted after the τ _{DPCH, n} delay from the boundary reference of the P-CCPCH frame and the reverse channel signal is reached at the time point 111 of τ _{DPCH, n} + T0 + Tref. In response, the mobile station 120 transmits the reverse channel signal after a delay of "T0 + β" from the reception point of the forward channel signal to reach the reference time point 111 of the base station 110. Here, β is a value for adjusting the transmission time of the reverse channel to reach the reference time point 111 and is information calculated from the base station 110 and provided to the mobile station 120. During operation, "β = T0 + Tref-RTT "Is calculated according to the formula. RTT is the interval between the transmission time of the forward signal and the reverse signal reception time at the base station.

On the other hand, β may be a value calculated and reported by the base station as described above, but may be changed little by little by tracking as the mobile station moves during mode change or call setup. It may be a value.

In FIG. 1, "T0 + β", which is the time interval between the forward channel reception and reverse channel transmission at the mobile station 120, for example β> 256 chips, is much higher than the nominal value T0 in a typical asynchronous W-CDMA system. If it has a large value, the transmission time 121 of the reverse channel is out of the range of "T0 ± 148 chips", and the time when the power control command for the reverse channel on the forward channel is applied is delayed, causing loss of power control. Can be. On the contrary, even if the time interval is smaller than T0 (for example, β <-256 chips), there is not enough time to apply the power control command, so that the power control command is applied in the next slot, which may cause a problem due to power control delay.

The figure also shows a situation where a new radio link is added in a soft handover situation (i.e., RL1 is the radio link of the previous cell, RL2 is the radio link of the target cell), where the new radio link RL2 is the mobile station ( In the reverse channel transmission time 121 at 120, the time point before T0 is added as a reference time point to be added to the ± 128 chip. However, at this time, if the transmission / reception time interval in the mobile station 120 is outside the "T0 ± 148 chip" range defined in the asynchronous W-CDMA standard, the mobile station designed according to this standard may not add a new radio link, or There is a problem that requires additional hardware (memory, etc.) for the case where the distance between the forward channels is far.

In conclusion, when the current USTS technique is applied to a large cell of an asynchronous W-CDMA system, there is a problem that the time interval between receiving a forward channel and transmitting a reverse channel at the mobile station may be too large or too small. Therefore, if the interval between the forward channel reception and the reverse channel transmission is out of the range defined in the asynchronous W-CDMA, there is a problem of power control delay, and the combination of the forward channel is delayed during soft handover. There is a problem that additional hardware is required.

The present invention was created to solve the above problems, and its object is to apply the USTS technology to the W-CDMA system, and the forward reception time and the reverse transmission time in the mobile station caused by the increase in cell size in the existing USTS technology. The present invention aims to provide a method of applying a USTS for a W-CDMA system in a wide area cell to solve the gap problem and to optimize and apply the USTS technology regardless of the cell size.

FIG. 1 is a diagram for explaining an example of a problem that may occur when USTS is generally applied to a wide area cell.

FIG. 2 is a timing diagram illustrating an example of a method for applying a wide cell to a USTS for a W-CDMA system according to the present invention. FIG. 2 is a timing relationship between a forward channel frame and a reverse channel frame in a base station when the method of the present invention is applied. Is a view showing,

FIG. 3 is a timing diagram illustrating another example of a method for applying a wide area cell of a USTS for a W-CDMA system according to the present invention. FIG.

FIG. 4 is a timing diagram illustrating another example of a method for applying a wide cell to a USTS for a W-CDMA system according to the present invention. FIG. 4 is a timing diagram when a state is changed to a USTS mode from a corresponding target cell by moving from an adjacent cell to a target cell. It is a figure explaining the control method in a base station,

FIG. 5 is a timing diagram illustrating another example of a method for applying a wide cell to a USTS for a W-CDMA system according to the present invention, wherein the mobile station gradually moves away from the base station to reduce the time interval between forward channel reception and reverse channel transmission. This is a timing chart explaining how to adjust this when it is out of the range required by the W-CDMA standard.

FIG. 6 is a timing diagram illustrating another example of a method for applying a wide cell to a USTS for a W-CDMA system according to the present invention, wherein a mobile station is gradually getting closer to the base station, thereby reducing the time interval between forward channel reception and reverse channel transmission. This is a timing chart explaining how to adjust this when it is out of the range required by the W-CDMA standard.

7 is a diagram for explaining a scrambling code offset determination when applying the present invention.

※ Explanation of code for main part of drawing

110,310,410,510,610,710: base station 120,320,420,520,620,720: mobile station

In order to achieve the above object, a wide area cell application method of a backward synchronization transmission method (USTS) for a wideband code division multiple access (W-CDMA) system according to the present invention is a wideband code division multiple access (W-CDMA) system. When applying the reverse synchronous transmission scheme (USTS) to the reverse channel, the time interval between the forward channel reception and the reverse channel transmission in the mobile station, regardless of the cell size, satisfies the range required by the specification of the asynchronous W-CDMA system. CLAIMS 1. A method for operating the USTS in USTS, the method comprising: setting a synchronization reference time value (Tref) for synchronization of a reverse channel; And a result of adding up the value of the synchronization reference time value Tref and an integer multiple of the repetition period value of the channel code, respectively, as the synchronization reference time value Tref, n for synchronization of the reverse channel for each mobile station in the same cell. Wherein, the integer comprises a second step of setting based on the time delay value for the transmission and reception signal between the corresponding mobile station and the base station.

In addition, in order to achieve the above object, in the method for applying a wide cell of the USTS for the W-CDMA system according to the present invention, the method of the present invention, which is applied at the initial call establishment, is a synchronization reference time value for synchronization of a reverse channel. (Tref) is set in units of cells, and the result value obtained by adding the synchronous reference time value Tref and the integer multiple of the repetition period value of the channel code is a synchronization reference for synchronization of the reverse channel with respect to each mobile station in the same cell. A first step of setting each of the time values Tref, n; Obtaining a round trip delay (RTD) value between the mobile station and the base station based on the transmission of the forward channel signal and the reception of the reverse channel signal; A third step of finding a synchronization reference time value (Tref, n) of which the absolute value of the difference value between the round trip delay time values is the minimum among the plurality of synchronization reference time values (Tref, n); And setting the found synchronization reference time value Tref, n as the synchronization reference time value Tref, n for the corresponding reverse channel synchronization, and setting the minimum difference value as time information for adjusting the initial transmission time of the reverse channel signal. T _{INIT_SYNC} ), and the fourth step of providing the mobile station with the corresponding T _{INIT_SYNC} .

Further, in order to achieve the above object, in the wide cell application method of the USTS for the W-CDMA system according to the present invention, when the state is changed from the corresponding cell to the USTS mode by handover from the neighbor cell to the target cell, The control method in the base station sets the synchronization reference time value Tref for synchronization of the reverse channel, and adds the result value obtained by adding the multiple times of the synchronization reference time value Tref and the repetition period value of the channel code to the same value. A first step of respectively setting a synchronization reference time value (Tref, n) for synchronization of a reverse channel for each mobile station in the cell; A second step of receiving time information (Rx-Tx) of a forward channel signal reception time and a reverse channel signal transmission time interval of a corresponding mobile station through reception of a reverse channel before changing to the USTS mode; Expected transmit / receive time interval values obtained by adding each difference value between the reception time point of the reverse channel and the synchronization reference time values adjacent thereto to the reported transmit / receive time interval information (Rx-Tx), and the estimated transmit / receive time interval value A third step of selecting a value close to the preset time information T0 as a basic value between a forward channel signal reception and a reverse channel signal transmission time at the mobile station; And setting the corresponding synchronization reference time value corresponding to the selected value as the synchronization reference time value of the corresponding channel, and setting a difference value between the set synchronization reference time value and the reception time of the reverse channel to the reverse channel signal of the mobile station. It comprises a fourth step of providing as a transmission time adjustment value of the information.

The mobile station, having received the transmission time adjustment value information by the fourth step, changes the timing of the reverse channel signal from the last transmission time of the reverse channel signal before the change to the USTS mode to the USTS mode. It is characterized by adjusting to the time of transmission of the signal.

In addition, in order to achieve the above object, in the wide cell application method of the USTS for the W-CDMA system according to the present invention, the mobile station gradually moves away from the base station so that a transmission / reception time interval at the mobile station is required for the W-CDMA range. In case of departure, the method of adjusting the delay delays the transmission time of the reverse channel by the repetition period value of the channel code at the scheduled time between the base station and the mobile station, and synchronizes the preset reverse channel with respect to the mobile station. The time value Tref, n may be increased by the repetition period value of the channel code.

Further, in order to achieve the above object, in the wide cell application method of the USTS for the W-CDMA system according to the present invention, a method for adjusting the transmission / reception time interval when the mobile station is gradually closer to the corresponding base station is out of the required range. Delays the transmission time of the forward channel by the channel code repetition period value from the reference transmission time at the promised time of the base station and the mobile station, and synchronizes the synchronization reference time value for synchronization of the preset reverse channel with respect to the mobile station. Tref, n) is reduced by the repetition period value of the channel code.

Hereinafter, a wide cell application method of the USTS for a W-CDMA system according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a timing diagram illustrating an example of a method for applying a wide cell to a USTS for a W-CDMA system according to the present invention. FIG. 2 is a timing relationship between a forward channel frame and a reverse channel frame in a base station when the method of the present invention is applied. The figure which shows.

In FIG. 2, τ _{DPCH, 1 to} τ _{DPCH, 3} are forward null frames DPCH1 DL (DPCH2 DL) (DPCH3 DL) for the first to third mobile stations, respectively, from the frame boundary of the forward common channel (P-CCPCH). T0 is a 1024 chip as a nominal transmission / reception time interval at the mobile station, and DPCH1 UL, DPCH2 UL and DPCH3 UL are reverse channel frames of the first to third mobile stations viewed from the base station, respectively. , Tref, 1 is a synchronization reference time value for synchronization of the reverse channel to the first mobile station, Tref, 2 is a synchronization reference time value for synchronization of the reverse channel to the second mobile station, Tref, 3 is a third mobile station In other words, when the first mobile station is described as an example, the base station determines a forward channel frame (DPCH1 DL) for the first mobile station from the P-CCPCH frame boundary, τ _{DPCH, 1.} Send after a delay _, Receive a reverse channel frame DPCH1 UL from the first mobile station at time ₁ + T0 + Tref, 1 '.

Referring to the figure, in the present invention, one Tref value is determined for each cell, but a separate Tref, n value is set for each mobile station, and the value is appropriately determined according to a time delay between the mobile station and the base station. However, the value obtained by dividing Tref, n by 256 is limited to Tref so that orthogonality of reverse channels can be maintained.

That is, in the same drawing, three mobile stations operate with USTS. The first and second mobile stations have different τ _{DPCH, n} but have the same Tref, n value (Tref, 1 = Tref, 2). In this case, the forward channel transmission time and the reverse channel reception time for the two mobile stations are different, but the time interval from the forward channel transmission to the reverse channel reception has the same value. The third mobile station is a case in which the first and second mobile stations and Tref, n have different values (Tref, 3 = Tref + 256 * 2), wherein the time interval between the two channels is different from the above two cases. Have.

In summary, the present invention is based on the above description. Each cell sets one synchronization reference time value Tref for synchronization of a reverse channel, and 256 chips, which is a repetition period of one synchronization reference time value Tref and a channel code. 'Tref + 256 * k' is set as the synchronization reference time value (Tref, n) for synchronization of the reverse channel with respect to each mobile station in the same cell. It sets based on the time delay value for the transmission / reception signal between the corresponding mobile station and the base station.

3 is a timing diagram illustrating another example of a method for applying a wide cell to a USTS for a W-CDMA system according to the present invention, and illustrates an example of applying the present invention to initial call setup.

When the initial call is established in the USTS mode by applying the present invention, the reverse channel transmission time adjustment values T _{INIT_SYNC} and Tref, n are newly determined.

In the conventional method, a round trip delay (RTD) between a mobile station and a base station is obtained by using a time delay of an access channel during initial call setup, and 'Tref-RTD' is determined as T _{INIT_SYNC} . However, in the case of the present invention, since Tref, n may have a plurality of values as described above with reference to FIG. 2, select Tref, n where the absolute value of 'Tref, n-RTD' becomes the smallest and then 'Tref, n-RTD' of T _{INIT_SYNC} is determined. In the figure, the case where Tref, n is Tref (indicated by a dashed line) and Tref + 256 (indicated by a solid line) are compared. In this case, the absolute value of 'Tref, n-RTD' is higher. It is small, indicating that Tref, n is determined to be Tref + 256.

That is, in the present invention, a round trip delay (RTD) value between the mobile station and the base station is obtained based on the transmission of the forward channel signal and the reception of the reverse channel signal between the base station 310 and the mobile station 320. The absolute value of the difference value between the round trip delay time value RTD among the plurality of synchronization reference time values Tref, Tref, 1 .... Tref, n set in the corresponding base station 310 is a synchronization reference time value that is minimum. Find Tref, 1. The found synchronization reference time value Tref, 1 is set as a synchronization reference time value for reverse channel synchronization of the mobile station 320, and the minimum difference value ΔT is time information for adjusting initial transmission time of the reverse channel signal. T _{INIT_SYNC} is provided to the mobile station. The synchronization reference time value Tref, 1 set in the base station 310 finds k, which is the minimum of the absolute value of "Tref ± 256k-RTD," and substitutes k into the formula of "Tref, n = Tref + 256k". Where k is an integer and 256 represents a repetition period value of the channel code.

FIG. 4 is a timing diagram illustrating another example of a method for applying a wide cell to a USTS for a W-CDMA system according to the present invention. FIG. 4 is a timing diagram when a state is changed to a USTS mode from a corresponding target cell by moving from an adjacent cell to a target cell. It is a figure explaining the control method in a base station.

Unlike the initial call setup in FIG. 3, when the USTS mode is changed, the forward and reverse channels are already transmitted. The time interval (Rx-Tx) between the forward channel reception and the reverse channel at the mobile station is T0. Can be different from. Therefore, in consideration of this, it is necessary to newly set the Tc value and Tref, n corresponding to the T _{INIT_SYNC} value at the time of initial call setup.

In the case of the mode change, since the call is already in progress, the round trip time (RTT), which is the time from the base station 410 to transmitting the forward channel after receiving the forward channel, can be known. Since the time interval information (Rx-Tx) between the reception of the forward channel and the transmission of the reverse channel can be measured, the transmission time of the reverse channel is adjusted by calculating Tref, n and Tc at this time in consideration of these values.

At this time, there are two ways to adjust the transmission time. The first is to select the Tref, n value so that the transmission / reception time interval is closest to T0 without adjusting the transmission time of the reverse channel at the mobile station, and then the reverse direction. It is to adjust the transmission time of the channel. The second method is to adjust the delayed transmission time unconditionally so that there is no loss of data symbols. In this case, adjust the Tref, n to the smallest value of the Tref, n values after the reverse channel reception. If the transmission / reception time interval at the mobile station is out of a predetermined range (for example, T0 +/- 128 chip) when the transmission time of the reverse channel is delayed in accordance with the delay time, the transmission / reception time interval at the mobile station is adjusted by adjusting τ _{DPCH, n} . It must be allowed to fall within the defined range. (In this case _, since the value of τ _{DPCH, n} is increased _{, the} value of Tref, n eventually decreases as the value of τ _{DPCH, n} is increased.)

In the example of the figure, the base station 410, through the reception of the reverse channel before the change to the USTS mode, time information on the interval between the forward channel signal reception time and the reverse channel signal transmission time of the mobile station 420 ( Rx-Tx) is reported. In the received transmission / reception time interval information Rx-Tx, a difference value (-DELTA T1, DELTA T2) between the reception time point 411 of the reverse channel and the synchronization reference time values Tref, Tref, 1 adjacent thereto is provided. Calculate the sum of the expected transmit / receive time interval values, that is, (Rx-Tx) + (-ΔT1) and (Rx-Tx) + (ΔT2), and the two expected transmit / receive time interval values (Rx-Tx) + (-Δ T1) and (Rx-Tx) + (ΔT2) are values close to the preset time information T0 as a basic value between the forward channel signal reception and the reverse channel signal transmission time at the mobile station 420, that is, (Rx- Select Tx) + (ΔT2).

The base station 410 sets the synchronization reference time value Tref, 1 corresponding to the selected value Rx-Tx + (ΔT2) to the synchronization reference time value Tref, n of the channel for the corresponding mobile station 420. In addition, the difference value DELTA T2 between the set synchronization reference time value Tref, 1 and the reception time point 411 of the reverse channel is provided as the transmission time adjustment value information Tc of the reverse channel signal of the mobile station 420.

The mobile station 420, having received the transmission time adjustment value information Tc, adjusts the time point 422 adjusted by the provided adjustment value Tc to the USTS mode at the last transmission time point 421 of the reverse channel signal before the change to the USTS mode. If it is changed, adjust the transmission time of the corresponding reverse channel signal.

FIG. 5 is a timing diagram illustrating another example of a method for applying a wide cell to a USTS for a W-CDMA system according to the present invention, wherein the mobile station gradually moves away from the base station to reduce the time interval between forward channel reception and reverse channel transmission. This is a timing chart illustrating how to adjust the W-CDMA when it is out of the range required by the standard.

When the mobile station (UE) 520 near the base station 510 gradually moves away from the base station as shown in (a) to (b), initially adjust the β value as β1 → β2 to compensate for the large time delay. As a result, the transmission time at the mobile station 420 becomes faster, and thus the transmission / reception time interval Rx-Tx at the mobile station 420 becomes narrower. When this value is out of the predetermined T0 ± 128 chip range, as shown in (b), the transmission time 521 of the previous reverse channel is delayed by 256 chips, and the new transmission time 522 is set as well. Increasing by, the transmission / reception interval Rx-Txnew at the mobile station 520 falls within the range of T0 ± 128 chips as shown in FIG.

At this time, the offset of the common scrambling code of the reverse channel is also increased by 256, but for the mobile station 520, the original scrambling code may continue to be generated even during 256 chip intervals in which data symbols are not transmitted due to the delay. You do not need to make special adjustments to the scrambling code.

In addition, in the example of FIG. 5, adjusting the reverse channel transmission time point from 521 to 522 is performed at the time point promised between the mobile station 420 and the base station 510, and the transmission and reception time points are assigned to the mobile station 520. The base station 510 adjusts the transmission time, and if the transmission time of the reverse channel is adjusted through such a process, the transmission / reception time interval in the mobile station 520 can be maintained within a predetermined range.

FIG. 6 is a timing diagram illustrating another example of a method for applying a wide cell to a USTS for a W-CDMA system according to the present invention, wherein a mobile station is gradually getting closer to the base station, thereby reducing the time interval between forward channel reception and reverse channel transmission. This is a timing chart illustrating how to adjust the W-CDMA when it is out of the range required by the standard.

When the mobile station 620 far away from the base station 610 moves closer toward the base station 610 as shown in (a) to (b), at first, β value is converted into β1 → β2 to compensate for the decrease in time delay. As a result, the transmission time at the mobile station 620 is gradually delayed, and thus the transmission / reception time interval Rx-Tx at the mobile station 620 is gradually increased. If this value is out of the defined range, the transmission time 611 of the forward channel is delayed by 256 chips to be set as a new transmission time 612, resulting in increasing τ _{DPCH, n} by 256 chips and Tref, n value of 256 chips. Reduced by. At this time, the transmission time of the reverse channel is not changed, but when the forward channel is received, the reverse channel is transmitted as fast as 256 chips.

In this case, the offset value of the common scrambling code does not change. The reason is that the common scrambling code of the reverse channel is maintained at a predetermined time point from the reference time (P-CCPCH) of the base station, and the arrival time of the base station of the reverse channel has not changed with respect to the reference time (P-CCPCH) of the base station. That is, the scrambling code offset of each mobile station with respect to the common scrambling code is affected by Tref, n and τ _{DPCH, n} . As τ _{DPCH, n} increases, the scrambling code offset increases, and when Tref, n decreases, the scrambling code offset decreases. In this case, τ _{DPCH, n} increased by 256 and Tref, n decreased by 256. The offset is not changed.

In the example of FIG. 6, the forward channel transmission time adjustment is performed at a time point promised between the mobile station and the base station, and the reception and transmission time points are adjusted by the mobile station and the base station, respectively. By adjusting, the transmission / reception time interval at the mobile station can be kept within a predetermined range.

7 is a diagram for explaining a scrambling code offset determination when applying the present invention.

In the application of the present invention, the scrambling code offset of each mobile station should be determined in consideration of the reference time (P-CCPCH) at the base station 710 and Tref, n, τ _{DPCH, n} . In the figure, the scrambling code reference time at the base station is set to T0 + Tref from the P-CCPCH frame boundary 711 as shown in (c) and two cases are set to the P-CCPCH frame boundary 711 as shown in (d). (d) is showing. (a) shows a forward channel frame, and (b) shows a reverse channel frame received at the base station 710.

In the case of (c), the scrambling code offset is calculated by the expression 'τ _{DPCH, n} + [Tref, n / 256] x 256' and is determined by the values of the variables τ _{DPCH, n} and Tref, n. Since the value of τ _{DPCH, n} is basically a value known to the mobile station by system information, it is only necessary to know how far Tref, n is 256 chip units from Tref. In the above formula, [] means the largest value among integers less than or equal to the number in [].

In the case of (d), the scrambling code offset is calculated by the formula of 'T0 + Tref + τ _{DPCH, n} + [Tref, n / 256] x 256'. In this case, in order to determine the offset of the scrambling code, In comparison with the case, additional Tref value information should be known at the mobile station.

Therefore, in the case of applying the present invention, when the mobile station operating in the USTS mode first establishes a call, the soft handoff (to decode the reverse channel in a new cell), the case of performing a mode change to the USTS mode, and the like, In consideration of the reference time at the base station of the common scrambling code, scrambling code offset information for each mobile station or information for obtaining the value should be transmitted to the mobile station and the base station.

As described in detail above, according to the method for applying a wide cell to the USTS for the W-CDMA system according to the present invention, the USTS technology can be applied regardless of the cell size, and the USTS technology can be applied to a large cell. The effects of solving the problem of power control delay which may occur during the connection or combining of forward channels during soft handover are created.

Claims (9)

When applying the backward synchronous transmission scheme (USTS) to a wideband code division multiple access (W-CDMA) system, the time interval between the forward channel reception and the reverse channel transmission in the mobile station is asynchronous W-CDMA system regardless of the cell size. In the method for operating the reverse channel to the USTS while satisfying the range required by the standard of, Setting a synchronization reference time value (Tref) for synchronization of a reverse channel; And The result value obtained by adding up the synchronous reference time value Tref and the integer multiple of the repetition period value of the channel code is respectively set to the synchronous reference time value Tref, n for synchronization of the reverse channel for each mobile station in the same cell. Wherein, the integer comprises a second step of setting based on the time delay value for the transmission and reception signal between the mobile station and the base station, the reverse synchronous transmission for wideband code division multiple access (W-CDMA) system Wide cell application method of the scheme (USTS). When applying the backward synchronous transmission scheme (USTS) to a wideband code division multiple access (W-CDMA) system, the time interval between the forward channel reception and the reverse channel transmission in the mobile station is asynchronous W-CDMA system regardless of the cell size. In the control method in the base station at the time of initial call setup to operate the reverse channels to the USTS while satisfying the range required by the specification of A synchronization reference time value (Tref) for synchronizing the reverse channel is set, and a result value obtained by adding up an integer multiple of the synchronization reference time value (Tref) and the repetition period value of the channel code is reversed for each mobile station in the same cell. A first step of respectively setting a synchronization reference time value (Tref, n) for synchronization of the channel; Obtaining a round trip delay (RTD) value between the mobile station and the base station based on the transmission of the forward channel signal and the reception of the reverse channel signal; A third step of finding a synchronization reference time value (Tref, n) of which the absolute value of the difference value between the round trip delay time values is the minimum among the plurality of synchronization reference time values (Tref, n); And The found synchronization reference time value Tref, n is set to the synchronization reference time value Tref, n for the corresponding reverse channel synchronization, and the minimum difference value is time information T for initial transmission time adjustment of the reverse channel signal. _And a fourth step of providing the corresponding mobile station to _{INIT_SYNC} ). The method of claim 1, wherein the wideband cell transmission method of the uplink synchronous transmission method (USTS) for the wideband code division multiple access (W-CDMA) system. The method of claim 2, In the fourth step, the set synchronization reference time value Tref, n finds k, which is the minimum of the absolute value of "Tref ± 256k-RTD", and converts k to the expression of "Tref, n = Tref + 256k". A value obtained by substitution, where k is an integer and 256 is a repetition period value of the channel code, and the wide cell code application method of the backward synchronization transmission method (USTS) for the wideband code division multiple access (W-CDMA) system . When applying the backward synchronous transmission scheme (USTS) to a wideband code division multiple access (W-CDMA) system, the time interval between the forward channel reception and the reverse channel transmission in the mobile station is asynchronous W-CDMA system regardless of the cell size. In the control method at the base station when the reverse channel to operate in the USTS while satisfying the range required by the standard of the USTS, the handover from the neighbor cell to the target cell to change the state from the corresponding target cell to the USTS mode, A synchronization reference time value (Tref) for synchronizing the reverse channel is set, and a result value obtained by adding an integer multiple of the synchronization reference time value (Tref) and the repetition period value of the channel code is reversed for each mobile station in the same cell. A first step of respectively setting a synchronization reference time value (Tref, n) for synchronization of the channel; A second step of receiving time information (Rx-Tx) of a forward channel signal reception time and a reverse channel signal transmission time interval of a corresponding mobile station through reception of a reverse channel before changing to the USTS mode; Expected transmit / receive time interval values obtained by adding each difference value between the reception time point of the reverse channel and the synchronization reference time values adjacent thereto to the reported transmit / receive time interval information (Rx-Tx), and the estimated transmit / receive time interval value Selecting a value close to the preset time information T0 as a basic value between a forward channel signal reception and a reverse channel signal transmission time at the mobile station; And The synchronization reference time value corresponding to the selected value is set as the synchronization reference time value of the corresponding channel, and the difference value between the set synchronization reference time value and the reception time of the reverse channel is set to the reverse channel signal of the mobile station. And a fourth step of providing the transmission time adjustment value information. 2. A method of applying a wideband cell of a backward synchronization transmission method (USTS) for a wideband code division multiple access (W-CDMA) system. The method of claim 4, wherein The mobile station, having received the transmission time adjustment value information, adjusts the time when the transmission / reception of the reverse channel signal is changed from the last transmission time of the reverse channel signal before the change to the USTS mode by the provided adjustment value to the USTS mode. And further comprising a fifth step of applying a wideband cell to a backward synchronous transmission scheme (USTS) for a wideband code division multiple access (W-CDMA) system. When applying the backward synchronous transmission scheme (USTS) to a wideband code division multiple access (W-CDMA) system, the time interval between the forward channel reception and the reverse channel transmission in the mobile station is asynchronous W-CDMA system regardless of the cell size. In the method of adjusting the reverse channel to the USTS while satisfying the range required by the standard of the mobile station, when the mobile station gradually away from the base station and the transmission and reception time interval is out of the request range, At the scheduled time of the base station and the mobile station, the delay time of the reverse channel transmission is delayed by the repetition period value of the channel code, and the synchronization reference time value (Tref, n) for synchronization of the reverse channel preset for the mobile station is And a repeating period value of the channel code is increased. The method of applying a wideband cell of a backward synchronous transmission method (USTS) for a wideband code division multiple access (W-CDMA) system. The method of claim 6, And wherein said mobile station generates a scrambling code continuously during said delay period as well. When applying the backward synchronous transmission scheme (USTS) to a wideband code division multiple access (W-CDMA) system, the time interval between the forward channel reception and the reverse channel transmission in the mobile station is asynchronous W-CDMA system regardless of the cell size. In the method of adjusting the reverse channel to the USTS while satisfying the range required by the standard of the mobile station, the mobile station is gradually closer to the base station, if the transmission and reception time interval is out of the required range, At the promised time of the base station and the mobile station, the transmission time of the forward channel is delayed by the channel code repetition period value from the reference transmission time, and the synchronization reference time value (Tref) and n) decreases by the repetition period value of the channel code. The method according to any one of claims 1, 4, 6 and 8, And a repeating period value of the channel code is 256 chips. 5. The method of claim 1, wherein the repetition period value of the channel code is 256 chips.