KR20020068700A - Method for controlling timming for USTS - Google Patents

Abstract

PURPOSE: A method for controlling a timing for a USTS(Uplink Synchronous Transmission System) is provided to enhance a control frequency of a TPC(Transmit Power Command) bit for USTS, enhance a power control performance, and remove an unnecessary TAB(Timing Alignment Bit) transmission by lengthening a transmission period of TAB information and transmitting TAB information. CONSTITUTION: A node B compares a receiving signal timing from a UE(User Equipment) with a desired timing per every 200ms. If the receiving signal timing is quicker than the desired timing, the node B sets a TAB as "0". If the receiving signal timing is slower than the desired timing, the node B sets a TAB as "1". The node B skips every 3 frames, replaces the 14th TPC with a TAB, and transmits the replaced TAB. The UE performs a hard decision as to the TAB, combines 5 information according to "0" or "1", and adjusts a timing by a designated unit.

Description

Timing Control Method for Uplink Synchronous Transmission Method [Method for controlling timming for USTS}

The present invention is to control the timing to obtain an Uplink Synchronous Transmission System (USTS) in a mobile communication system, and in particular, to maintain the timing obtained from initial synchronization in a 3GPP system. The present invention relates to a method for transmitting a timing alignment bit (TAB) by replacing a transmit power command (TPC) for power control.

More specifically, the present invention provides a method for performing a timing update value determination for maintaining a reverse synchronous transmission scheme (USTS), in which the TPC is crossed at least one frame from the base station to the mobile station (UE) by the TAB bit of the DCH associated with the USTS channel. In transmission by replacing, the TAB bit transmission period is longer than the conventional method, thereby increasing the control frequency of the TPC bit for the USTS, thereby improving power control performance and preventing unnecessary TAB transmission.

In order to perform the timing update decision, the TAB bit is transmitted in five periods of 40 ms over three frames and four TABs in four 50 ms periods over four frames, or two TABs in 100 ms periods over nine frames. Is sent.

In general, in the 3GPP system, the Uplink Synchronous Transmission Scheme (USTS) is currently being considered as an additional technology.

USTS is called uplink synchronous transmission technology, and data transmitted from all user equipments (UE) is divided and transmitted with same scrambling code and different orthogonal codes. It is a kind of interference cancellation technique that reduces interference in a cell by allowing B to arrive at the same point in time.

Timing control to obtain USTS consists of two steps: initial synchronization and tracking. Initial synchronization is a process of obtaining rough timing synchronization, and tracking is a process of maintaining timing obtained from initial synchronization. Normally, initial synchronization is performed during the call setup. In some cases, the initial synchronization can be omitted and the tracking process can be performed immediately.

The tracking process for USTS undergoes closed loop timing control, which is similar to a power control loop.

That is, the base station Node B compares the reception signal timing from the mobile station UE with a desired time timing every 200 ms. If the timing of the received signal is fast, the timing alignment bit (TAB) is set to "0".

The TAB transmits by replacing every 14 frames of the 14th TPC (Transmit Power Control). The mobile station UE makes a hard decision on the TAB and combines 10 pieces of information according to " 0 " or " 1 " to adjust time timing by a predetermined unit.

Timing control of the USTS is performed in connection with a dedicated channel (DCH).

1 shows the configuration of a Donwlink DCH channel.

Referring to FIG. 1, the downlink DCH channel is composed of a radio frame having a frame period (T _f ) = 10 ms, has 15 slots (Slot # 0 to Slot # 14), and any one slot T _slot. = 2560 chips, 20 * 2 ^k bits (k = 0..7), with DPDCH (Dedicated Physical Data CHannel) and DPCCH (Dedicated Physical Control CHannel) It is. The first DPDCH carries N _data1 bits of data (Data1), and the next DPCCH carries TPC command N _TPC bits and TFCI N _TFCI bits, and the next DPDCH carries N _data2 bits of data (Data2). In the end, the DPCCH carries a _pilot of N _pilot bits.

Here, the TFCI bit contains information about the channel currently being transmitted. For example, information about the amount of data and the coding method transmitted in the radio frame to be transmitted is transmitted.

In the case of USTS, TPC information and TAB information should be alternately transmitted to the TPC field through the DCH. As described above, the TAB bit transmitted in the 14th slot is skipped every frame and transmitted by overwriting the TPC field.

On the other hand, the TPC is a TPC for power control of the uplink (reverse) channel. This is used to change the power of the uplink. The pilot is used to measure the power of the channel.

However, as described above, in transmitting the TAB information for controlling the timing for obtaining the conventional USTS, the timing update value decision period is modified from 20 ms to 200 ms to determine 10 TABs.

Therefore, the timing update value determination occurs once during 200 ms, and the frequent sending of the TAB even though the timing does not show much change in the 200 ms time eventually affects the performance of punctured TPC because the frequency of control of the TPC bits decreases. Since the decision is performed with 10 units of TAB, a few more transmissions do not significantly affect the decision that occurs once every 200 ms.

Accordingly, in order to solve the above problems, the present invention can increase the control frequency of the TPC bit for the USTS by transmitting the transmission period of the TAB information transmitted to maintain the timing obtained in the initial synchronization longer than the conventional method. We propose a method to increase power control performance and to eliminate unnecessary TAB transmission.

1 is a diagram showing the configuration of a Donwlink DCH channel

2 is a diagram illustrating the transmission of TAB information in a 40 ms transmission period for maintaining timing obtained in initial synchronization;

3 is a diagram illustrating sending TAB information in a 50 ms transmission period to maintain timing obtained in initial synchronization;

4 is a diagram illustrating sending TAB information in a 100 ms transmission cycle to maintain timing obtained in initial synchronization;

The present invention relates to a method of transmitting a timing alignment bit (TAB) by replacing a transmit power command (TPC) for power control of a dedicated channel (DCH) in order to maintain timing obtained from initial synchronization in a 3GPP system. A method comprising: transmitting a TPC by replacing at least one frame with a TAB bit in a downlink DCH channel; Determining a timing update value using the transmitted TAB bit, TAB transmission method of the dedicated channel for the reverse synchronous transmission method.

In the present invention, the transmission of the TAB bit is characterized in that the timing update value is determined by transmitting four TABs at 40 ms intervals over three frames and four TABs at 50 ms cycles over four frames or 100 ms cycles over nine frames.

Other objects and features of the present invention will become apparent from the detailed description of the embodiments with reference to the accompanying drawings.

Hereinafter, TAB (Timing Power Command) is replaced by replacing a transmit power command (TPC) for controlling timing to obtain an Uplink Synchronous Transmission System (USTS) according to the present invention with reference to the accompanying drawings. A method of transmitting an alignment bit will be described.

First, a general description of the present invention will be given.

According to the conventional proposal, the TAB bit is transmitted once every 20 ms and the timing update in the mobile station (UE) occurs once every 200 ms. Therefore, a decision must be made for timing update with 10 TAB bits. In the present invention, the TAB bit transmission frequency is newly performed at 40 ms, 50 ms and 100 ms.

Even when timing determination is performed by the new method described above, the TAB is punctured and transmitted to the TPC. However, the TAB is not changed but once every 40 ms or every 4 frames every 3 frames other than 20 ms transmitted every 1 frame. In other words, 100ms every other 50ms or 9 frames.

In the case of 40ms, the timing update value is decided with 5 TABs, and in the case of 50ms, the timing update value is determined with 4 TAB fields, and in the case of 100ms, the timing update value is finalized with 2 TAB fields.

Figure 2 shows the transmission of the TAB information in 40ms transmission period for maintaining the timing obtained in the initial synchronization.

As shown in the figure, the timing update value is determined using five TAB information by sending TAB information five times in a 40 ms period for 200 ms.

More specifically, the base station Node B compares the received signal timing from the mobile station UE to the desired time timing every 200 ms. If the received signal timing is fast, the timing alignment bit (TAB) is set to "0", and if it is slow, it is set to "1".

The TAB transmits every 3 frames by replacing the 14th TPC (Transmit Power Control). The mobile station UE makes a hard decision on the TAB and combines five pieces of information according to " 0 " or " 1 " to adjust time timing by a predetermined unit.

For example, if four of the TAB values determined above are "1" and one is "0", the final decision is made to "1" and the timing update is adjusted accordingly. In this case, since the reception timing is slow, the reception timing is fixed. Increment by the table specified.

Figure 3 shows the transmission of the TAB information in 50ms transmission period for maintaining the timing obtained in the initial synchronization.

As shown in the figure, the TAB information is sent four times in 50 ms periods for 200 ms to determine the timing update value using four TAB information.

That is, the TAB transmits every four frames by replacing the fourteenth TPC (Transmit Power Control). The mobile station UE makes a hard decision on the TAB and combines four pieces of information according to " 0 " or " 1 " to adjust time timing by a predetermined unit.

The method of determining the timing update value according to the above is basically the same as the process described with reference to FIG. 2.

4 shows transmission of TAB information in a 100 ms transmission period for maintaining timing obtained from initial synchronization.

As shown in the figure, the TAB information is sent twice in 100 ms periods for 200 ms to determine the timing update value using the two TAB information.

That is, the TAB transmits every 9 frames by replacing the 14th TPC (Transmit Power Control). The mobile station UE makes a hard decision on the TAB and combines two pieces of information according to " 0 " or " 1 " to adjust time timing by a predetermined unit.

The method of determining the timing update value according to the above is basically the same as the process described with reference to FIG. 2.

As described above, the present invention uses the TAB bits of the DCH associated with the USTS channel from the base station to the mobile station (UE) in order to perform timing update value determination to maintain the backward synchronous transmission scheme (USTS). By transmitting 5 frames across 40ms, 4 frames over 50ms or 2 frames over 100ms, the control frequency of the TPC bits for USTS can be increased to improve power control performance and prevent unnecessary TAB transmission. The present invention relates to a TAB transmission method of a dedicated channel for a reverse synchronous transmission scheme.

Although the preferred embodiment of the present invention has been described above, the present invention may use various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments.

Therefore, the above description does not limit the scope of the present invention as defined by the limitations of the following claims.

According to the present invention, the transmission period of the TAB bit associated with the USTS is longer than the conventional method, thereby improving power control performance to increase the control frequency of the TPC bit for the USTS, and eliminating unnecessary TAB transmission.

Claims (2)

Transmitting a TPC by replacing at least one frame with a TAB bit on a downlink DCH channel; And determining a timing update value by using the transmitted TAB bit. The method of claim 1, wherein the transmitting of the TAB bits comprises transmitting five TAB bits at 40 ms intervals over three frames and two TAB bits at four ms or four frames at 100 ms intervals over nine frames over four frames. Timing control method.