KR20030026756A - Method for selecting sub-channel in physical layer of umts user equipment - Google Patents

Abstract

PURPOSE: A sub channel selecting method in physical layer of UMTS(Universal Mobile Telecommunication System) terminal is provided to minimize an interval between a previous preamble and a following next preamble when there is no acknowledgement from a UTRAN(UMTS Terrestrial Radio Access Network). CONSTITUTION: A process is to bring an ASC(Access Service Class) from an MAC(Media Access Control)(200). Just before a selection of a new sub channel, the sub channel number "m" of a selected preamble is stored(202). Thereafter, "new" as a sub channel number for transmitting newly is determined(204). A selection process of an access slot is performed by comparing a value added a minimum access slot(3AS) to "m" with a maximum access slot(12AS)(206,208). In case that the compared value is same or larger than the maximum access slot, a (m+3)=M mod 12 value is determined(210). Among valid sub channels, the existence of a sub channel having M-m numbers is confirmed(214). If the sub channel exists, the sub channel number is compared sequentially from M to m(218). Thereafter, the first founded sub channel number is allocated as "new"(222). An access slot is selected by considering a present SFN(System Frame Number) from the allocated "new"(226).

Description

U.M.T.S. Subchannel selection method in the physical layer of the terminal {METHOD FOR SELECTING SUB-CHANNEL IN PHYSICAL LAYER OF UMTS USER EQUIPMENT}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless terminal device of a U.S. t.

Typically, in the physical random access procedure mentioned in 3rd Generation Partnership Project (3GPP) TS25.214 (Technical Standard 25.214), the physical layer, which is Layer 1 of the UE, is a physical layer random access. After collecting various necessary parameters from radio resource control (RRC) and MAC (Media Access Control), which are upper layers, for transmission of a physical random access channel (PRACH), A sub-channel group and a preamble signature are selected for preamble transmission from a PRACH unit belonging to an access service class (ASC) received from a MAC. .

Here, the physical layer starts a PRACH random access procedure by a primitive called PHY access REQ, and the signature to be used as the corresponding preamble signature is randomly transmitted every time the preamble is transmitted during the corresponding preamble ramping cycle. One of the valid signatures of the corresponding PRACH portion is selected, but the selection for the subchannel is to use the first selected until the preamble ramping cycle ends. This is because the minimum distance between the preamble and the next preamble following it, τ _{pp, min} , must satisfy at least three hundred million access slots (AS). TS25.211 V3.3.0 V3.3.0 Considering the contents of valid uplink access slots for the various PRACH subchannels shown in Table 7 of Chapter 6.1.1, the time interval between the preamble and the following preamble must be at least 12AS. . The access slot is a unit obtained by dividing the 20 ms section into 15 pieces that coincide with the boundary of the system information message of 20 ms units transmitted by the base station in all directions. Thus, there are 15 access slots in one frame of 20 ms.

In more detail, during the corresponding preamble ramping cycle, a synchronization acquisition indication channel (UMRAN) from a Universal Mobile Telecommunications System Terrestrial Radio Access Network (RAN) (UTRAN) is used. When there is no response through a channel (hereinafter, 'AICH'), the preamble signature attempts random selection from valid signatures each time the preamble is retransmitted, while the preamble is transmitted at the time of transmitting the preamble. In the case of access slot selection, although there may be valid subchannel groups in a specific ASC provided from the MAC, there is no change in the subchannel number. In the preamble ramping cycle, the UE transmits a preamble for access to the UTRAN. If the UE does not receive the acknowledgment of the preamble in the first attempt, the next preamble increases and transmits a predetermined amount of power. If the acknowledgment is not received, the power of the next preamble is increased and transmitted. As such, it means a chunk having the maximum number of transmissions of the preamble that can be transmitted while increasing the power of the preamble without receiving acknowledgment from the base station UTRAN. In terms of time (x-axis) versus power (y-axis), the stairs appear as a triangular graph from the side.

For example, if 1 and 5 are received from the base station as a subchannel group, access slots between successive preambles are 1, 13, 10, 7, 4 if only a subchannel of 1 is used during the preamble ramping cycle. Can be. If the SFN at the time of the first preamble transmission is 0, the UE will transmit the first preamble in AS 1, and if the second A is not received, the subsequent second preamble is fixed to the sub-channel as 1 before 12AS. Is transmitted from the 13th AS.

Therefore, when the preceding preamble is transmitted in the selected subchannel and there is no response from the base station, the access slot of the subsequent preamble is exactly 12AS different from the preceding preamble. That is _, a subsequent access slot that satisfies a distance greater than τ _{pp, min} (3 to 4 AS = 15360 or 20480 chips) representing the minimum distance between the preceding preamble and the next preamble following it is N times 12AS. (N = 1 to 4 or 5). This means that if subchannel number 0 is selected and the current System Frame Number ('SFN') is 8M (M = 0 ... 511), 7680 or 12800 chips for the first preamble transmission. If there is no acknowledgment from the UTRAN afterwards, the next frame, i.e. SFN mod 8 = 1, can be transmitted after 15360 or 20480 chips after the first preamble is transmitted, i.e. within the current frame. The next preamble is transmitted only in an access slot corresponding to an integer multiple of 12AS (61440 chip) corresponding to a frame.

This means that the preamble cannot be selected for a time interval of 3 to 11 AS. Accordingly, there is a limited problem in performing a quick random access procedure in PRACH transmission.

Accordingly, an object of the present invention is to physically layer a UMTS terminal to minimize the interval between the preceding preamble and the next preamble following it, L _pp when the UMTS terminal does not receive a response from the UTRAN in attempting random access. It provides a method for selecting a sub-channel in the.

Another object of the present invention is to shorten the time taken for the UMTS terminal to random access to obtain a faster RRC connection (Radio Resource Control Connection) and uplink (Random Access Channel, hereinafter called 'RACH') UL) to improve the overall speed of data transmission, thereby providing a method for reducing power waste of the terminal.

In order to achieve the above object, the present invention provides a method for selecting a subchannel in a physical layer of a UMTS terminal, and since a subchannel group exists in a specific ASC received from a MAC, a new signature is selected when a subsequent preamble is transmitted. Likewise, after transmitting the preceding preamble among the valid subchannel groups, the subchannel selects the subchannel so that the distance with the preceding preamble can be minimized while satisfying τ _pp > = τ _{pp, min} . The signature attempts random selection but the subchannel selection satisfies τ _pp > = τ _{pp, min} and gives priority to the direction in which the distance (L _pp, L _{pp, min} = 3AS) is the minimum. It is characterized by.

1 is a diagram considering a system frame number for determining an access slot number in a UMTS terminal according to an embodiment of the present invention;

2 is a control flowchart illustrating a method of selecting a subchannel in a physical layer of a UMTS terminal according to an embodiment of the present invention;

3 is a diagram illustrating a method for selecting a subchannel in a physical layer of a UMTS terminal according to an embodiment of the present invention with a code.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram considering a system frame number for determining an access slot number in a UMTS terminal according to an embodiment of the present invention, Figure 2 is a method for selecting a sub-channel in the physical layer of a UMTS terminal according to an embodiment of the present invention 3 is a diagram illustrating a method for selecting a subchannel in a physical layer of a UMTS terminal according to an embodiment of the present invention. Hereinafter, an operation for performing a method of selecting a subchannel in the physical layer of a UMTS terminal according to the present invention will be described in detail with reference to FIGS. 1 to 3.

According to the present invention, in the method of selecting a subchannel in the physical layer of a UMTS terminal, as shown in FIG. 1, when a current access slot is newly determined for preamble transmission, a subchannel applied to a preamble transmitted immediately before The preceding free of the subchannel numbers included in the valid subchannels of the ASC while satisfying more than distance 3AS (this is the case where AICH Transmission Timing is '0' and 4AS is 1) from the number. A method of selecting a subchannel having a number closest in time to an AS at the time of transmitting an emblem. The access slot number of the preamble to be newly transmitted is determined from the selected subchannel number. When determining the access slot number, the SFN applied at the time of transmission of the new preamble is considered. At this time, as shown in Fig. 1, a subchannel number is used. This is based on Table 7 of TS 25.214 V3.3.0.

Next, a control flowchart showing a method of selecting a subchannel in a physical layer of a UMTS terminal according to an embodiment of the present invention will be described in detail with reference to FIG. 2. As shown in FIG. 2, the ASC is obtained from the MAC (step 200). Subchannel number “m” for the selected preamble is stored immediately before selecting a new subchannel (step 202). In operation 204, a new subchannel number "new" is determined. Then, in step 206 and 208, the process of selecting an access slot by dividing a value obtained by adding the minimum access slot (3AS) to the maximum access slot (12AS) and distinguishing the case where the maximum access slot is greater than or equal to and smaller than the maximum access slot is performed. Proceeding (steps 206 and 208).

First, in the process of selecting the access slot, comparing the value obtained by adding the minimum access slot (3AS) to the maximum access slot (12AS) and explaining the case of being equal to or greater than the maximum access slot, (m + 3) = M mod A value 12 is determined 210 (step 210), and it is checked whether a sub channel having a number of M to m exists in the valid sub-channels (step 214). If there is a subchannel having a number of M to m among the valid subchannels in step 214, the subchannel numbers included in the valid subchannels are sequentially compared from M to m (218), and the first in the comparison is performed. The sub channel number to be found is set to "new" (step 222). In step 226, the access slot is selected in consideration of the current SFN from new set above.

On the other hand, in the process of selecting the access slot, the value of adding the minimum access slot (3AS) to the maximum access slot (12AS) compared to the smaller than the maximum access slot, and determines the value of (m + 3) = M (Step 212). In operation 216, the existence of the subchannels having M to 11 numbers is determined in the valid subchannels, and when the existence of the subchannels is confirmed, the subchannel numbers included in the valid subchannels are sequentially compared with each other starting with M (220). step). The first sub-channel number found in the comparison is selected as "new" (step 224), and an access slot is selected in consideration of the current SFN from the new set above (step 228).

FIG. 3 is a code illustrating a method of selecting a subchannel in a physical layer of a UMTS terminal according to an embodiment of the present invention as shown in the control flow diagram of FIG. 2, according to an AICH transmission timing. This code shows an algorithm for selecting the closest subchannel in time, that is, the next subchannel to be applied this time, compared to the available subchannels among the subchannels satisfying the condition of skipping.

As described above, in the subchannel selection method mentioned in the conventional TS 25.214, the distance between the preamble and the preamble is 12AS. However, the present invention can shorten the time it takes to perform the random access procedure by allowing a valid sub-channel allocated by the ASC currently assigned to it to select the nearest access slot satisfying 3AS or more. As a result, it is possible not only to prevent unnecessary power consumption of the terminal, but also to quickly obtain a response of the base station for PRACH transmission.

Claims (4)

In the method of selecting a sub-channel in the physical layer of the U.S.M.S terminal, Checking whether sub-channel groups exist in a specific access service layer received from a MAC layer of a data link layer of the terminal; If the subchannel groups are valid, the preceding preamble is transmitted among valid subchannel groups in the same way as newly selecting a signature when the subsequent preamble is transmitted among the subchannel groups, and then the minimum access slot is satisfied while the preceding preamble is satisfied. A method of selecting a subchannel in the physical layer of a U.S.MS terminal, characterized in that the subchannel is selected to minimize the distance to the preamble. The signature of claim 1, wherein the signature for attempting random selection is: The method for selecting a subchannel in the physical layer of the U.S.MS terminal, characterized in that the selection of the subchannel satisfies the minimum access slot or more and gives priority to the direction in which the distance is minimum. . In the method of selecting a sub-channel in the physical layer of the U.S.M.S terminal, Bringing a specific access service layer from a MAC layer of a data link layer of the terminal; Checking whether subchannel groups exist in the specific access service layer; If the sub channel groups exist, storing a sub channel number for the selected preamble immediately before selecting a new sub channel; Determining a subchannel number for the newly transmitted preamble; Comparing a maximum access slot with a minimum access slot plus a subchannel number for the selected preamble immediately before selecting the new subchannel; If the subchannel number plus the minimum access slot is equal to or greater than the maximum access slot, a subchannel having a number of M to m satisfying (m + 3) = M mod 12 exists in valid subchannels. To make sure that If the subchannel exists, sequentially comparing the subchannel numbers included in the valid subchannels from M to m; Setting a first subchannel number found in the comparison to a subchannel number for a newly transmitted preamble; And selecting an access slot in consideration of the current system frame number from the subchannel number for the newly transmitted preamble. In the method of selecting a sub-channel in the physical layer of the U.S.M.S terminal, Bringing a specific access service layer from a MAC layer of a data link layer of the terminal; Checking whether subchannel groups exist in the specific access service layer; If the sub channel groups exist, storing a sub channel number for the selected preamble immediately before selecting a new sub channel; Determining a subchannel number for the newly transmitted preamble; Comparing a maximum access slot with a minimum access slot plus a subchannel number for the selected preamble immediately before selecting the new subchannel; A process of confirming whether a subchannel having a number of M to 11 satisfying (m + 3) = M exists in valid subchannels when the value of adding the minimum access slot to the subchannel number is smaller than the maximum access slot. and, If the subchannel exists, comparing the subchannel numbers included in the valid subchannels sequentially from M; Setting a first subchannel number found in the comparison to a subchannel number for a newly transmitted preamble; And selecting an access slot in consideration of the current system frame number from the subchannel number for the newly transmitted preamble.