KR101248217B1 - Method and apparatus for setting system time in mobile communication system - Google Patents

Abstract

The present invention relates to a system time setting method and apparatus for reducing synchronization acquisition time in a mobile communication system supporting a hybrid terminal. The method of the present invention provides a method for detecting a preamble by receiving a control packet signal from a base station. And a second process of storing the position information of the detected preamble, outputting the information of the preamble by checking whether it is a correct preamble based on the position information of the previously detected and stored preamble, and whether to obtain initial synchronization. According to the third step of determining whether or not to use the information of the output preamble according to. The apparatus of the present invention, in the initial synchronization acquisition process, receives a control packet signal from a base station and detects a preamble, stores the position information of the detected preamble, and stores the position information of the preamble previously detected and stored based on the position information of the preamble. And a post-processing unit for outputting the information of the preamble by checking whether it is a correct preamble, and a multiplexer for determining whether to use the information of the output preamble according to whether initial synchronization is obtained.

EV-DO, hybrid terminal, control packet

Description

METHOD AND APPARATUS FOR SETTING SYSTEM TIME IN MOBILE COMMUNICATION SYSTEM}

1 is a block diagram showing an apparatus for a system time setting method in a terminal of an EV-DO system;

2 is a diagram illustrating a best case of system time setting in a terminal of an EV-DO system.

3 is a diagram illustrating a worst case system time setting in a terminal of an EV-DO system;

4 is a block diagram illustrating a system time setting apparatus in an EV-DO system according to an exemplary embodiment of the present invention.

5 is a block diagram showing in detail the post-processing unit of FIG.

6 is a flowchart illustrating a system time setting method according to an exemplary embodiment of the present invention.

The present invention relates to a method and apparatus for synchronizing acquisition in a mobile communication system, and more particularly, to a method and apparatus for setting system time that can reduce synchronization acquisition time in a mobile communication system supporting a hybrid terminal.

In general, a terminal in a mobile communication system sets a system time by receiving a control channel packet during system initial operation to obtain synchronization and base station information.

Next, a system time setting method in a general mobile communication system will be described.

1 is a block diagram illustrating an apparatus for a system time setting method in a terminal 100 of an EV-DO system.
Referring to FIG. 1, the terminal 100 basically includes a plurality of fingers 101, a combiner 103, a Walsh decoder 105, an accumulator 107, and a detector ( 109.
Referring to the general system time setting method, the control channel packet coming through the fingers 101 is combined by the combiner 103. The combined data is decoded by the Walsh decoder 105, and the accumulator 107 accumulates the decoded data by a length that a preamble can have. The detector 109 then compares the accumulated data with a predetermined threshold value and detects the preamble according to the result value. That is, if the accumulated data is larger than a predetermined threshold value, it is determined that the preamble is detected. In FIG. 1, the PRM_ON indicates a time point at which a preamble is detected.

 Two control rates of 76.8 kbps and 38.4 kbps are used for the control channel used in the EV-DO (Evolution Data Only) system. In this case, there is a false alarm in which the system time is set incorrectly at 38.4 kbps where the control channel packet repeats at the starting point of the slot at 38.4 kbps. In a real wireless environment, false alarms occur in more various situations.

When such a false alarm occurs, the wrong system time is set in the part of setting the system time in the sync state, and the operation returns to the initial state or the ac state from the beginning. You may have a problem that needs to be started.

So, in order to solve this problem, in detecting the preamble for the control channel in the sync state, the next preamble is detected without setting the system time at the time of detecting the preamble first generated by software. After that, if the time difference from the previous one becomes 256 slots, the system determines that the preamble is detected at the normal position. If there is no 256 slot difference, wait for the next preamble to be detected and wait for the 256 slot difference.

The method is described with reference to FIGS. 2 and 3 below.

2 is a diagram illustrating a best case system time setting. Referring to FIG. 2, when a preamble of a control channel is first detected in software at 201, the detection time point 201 is stored and the detection time is waited for comparison. As shown in FIG. 2, when the next detection time 203 is found to be different from the first time when the preamble is detected 201 and 256 slots, the system time is set.

However, if there is no 256 slot difference, wait for the next preamble to be detected. When designing the preamble detector, it is considered that the probability of false alarms occurring twice in succession rarely occurs. The worst case when doing this is to wait for 256 x 3 slots as shown in FIG.

In this case, if the preamble is detected at 303 after one slot has passed after the first preamble is detected at 301, the preamble detector detects the preamble again since 250 slots are exceeded. The preamble is then detected at point 305 and at the next point 307 which takes as much as 256 x 3 slots. If you calculate this as time, it is approximately 1.28 seconds.

In this method, if the UE sets the system time at the moment when the false alarm for the preamble described above occurs, the UE may have an incorrect system time and eventually start again from the initial state.
In this case, the maximum time for receiving the sync message proposed in the standard may be exceeded 5 seconds, and the time to wait for the idle state to make a call by powering on the terminal. This lengthens and causes inconvenience to the user. In this way, a problem occurs in a hybrid terminal that simultaneously supports CDMA2000 1x (hereinafter, referred to as '1x') and EVDO even if it satisfies the 5 second sync message reception time given in the standard.

That is, in the case of the hybrid terminal, when the power-on of the first terminal is powered on, the system time setting for 1x is attempted, and after this is completed, the hybrid terminal of the EVDO system is in a sleep period in the idle state of 1x. Attempt to acquire. At this time, if the sleep period set in 1x is set to 1.28 seconds, which is the minimum unit, when the worst case occurs as shown in FIG. 3, the system time cannot be set in consideration of the operation time of another task. . That is, the system time setting of the EVDO may be continuously delayed because the EVDO needs to wait for the system acquisition until the next 1x sleep period.

Accordingly, an object of the present invention is to provide a system time setting method and apparatus for minimizing initial setting time in a mobile communication system supporting a composite terminal.

Another object of the present invention is to provide a system time setting method and apparatus which can reduce initial setting time without increasing complexity in a mobile communication system supporting a composite terminal.

The present invention for achieving the above object is a method for setting the system time in a terminal of a mobile communication system supporting a hybrid terminal, in the case of initial synchronization acquisition process by receiving a control packet signal from the base station to preamble A first process of detecting and storing the position information of the detected preamble, and checking whether the detected preamble is a correct preamble based on the position information of the previously detected and stored preamble, And a third process of determining whether or not to use the information about the output preamble according to whether initial synchronization is obtained.

The second process includes storing the position information of the detected preamble, and a preamble having a predetermined difference value from the position information of the detected preamble among the previously detected and stored position information of the preamble. And a step of outputting information on the detected preamble if the preamble having the detected position information and the predetermined difference value is present.

If there is no preamble having the position information of the detected preamble and the predetermined difference value, after storing the position information of the detected preamble instead of the position information of the previously detected and stored preamble Characterized in that the first process.

The position information of the detected or previously detected and stored preamble may be a half slot number corresponding to a position where the detected or previously detected and stored preamble is detected.

According to an aspect of the present invention, there is provided an apparatus for setting a system time in a terminal of a mobile communication system supporting a hybrid terminal. Store location information of the detected preamble, determine whether the detected preamble is a correct preamble based on previously detected and stored location information, and output information on the detected preamble; And a processing unit and a multiplexer for determining whether to use the information about the output preamble according to initial synchronization acquisition.

The post-processing unit may include a storage unit which stores the position information of the detected preamble, and a preamble having a predetermined difference value from the position information of the detected preamble among the position information of previously detected and stored preambles. And a comparator for outputting information on the detected preamble if there is a preamble having the detected position information of the preamble and the predetermined difference value.

If there is no preamble having the position information of the detected preamble and the predetermined difference value, the storage unit replaces the position information of the previously detected and stored preamble and replaces the position information of the detected preamble. Characterized in that the storage.

The position information of the detected or previously detected and stored preamble may be a half slot number corresponding to a position where the detected or previously detected and stored preamble is detected.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a detailed description of preferred embodiments of the present invention will be given with reference to the accompanying drawings. It should be noted that the same configurations of the drawings denote the same reference numerals as possible whenever possible. Specific details are set forth in the following description, which is provided to provide a more thorough understanding of the present invention. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The present invention proposes a method and apparatus for reducing the system time setting in a mobile communication system supporting a hybrid terminal. When a preamble is detected during an initial synchronization acquisition operation, the result is not immediately outputted to the final output. The half slot number is stored, and then the preamble is detected by checking whether the half slot number of the detected preamble is a predetermined value. In this description, since the EV-DO system is used, it should be noted that the slot difference is 256 slots. In the present invention, it is assumed that a false alarm does not occur at the same location within 256 slots. Hereinafter, a system setting apparatus and a method of the present invention will be described with reference to the accompanying drawings.

4 is a block diagram illustrating a system time setting apparatus 400 in an EV-DO system according to a preferred embodiment of the present invention. The system time setting device 400 of the present invention is the same as that of FIG.

Referring to FIG. 4, when the terminal enters an initial synchronization acquisition state, the detector 409 detects a preamble by checking whether the terminal is in a predetermined pattern from the data received from the accumulator 409. The post-processor 411 stores the half slot number corresponding to the detected preamble without setting the system time as soon as the detector 409 detects the preamble. In this case, the buffer size of the post-processing unit 411 is set such that only about 256 slots before the current preamble can be stored. However, the size of the buffer is not limited.

In addition, when the post processor 411 receives the preamble detected by the detector 409, the post processor 411 compares the half slot number of the preamble stored previously to determine whether the same value exists. If a half slot number having the same half slot number of the detected preamble is found in a pre-stored value, it is determined that the preamble is detected at the correct position and the preamble detection result is output.

The multiplexer (MUX) 413 operates selectively depending on whether the initial synchronization acquisition process of the present invention is performed. That is, in the initial synchronization acquisition process, the multiplexer enable signal MUX_EN is set to '1', and if the system time is set after the initial synchronization acquisition process, MUX_EN is set to '0' to perform the conventional method. The reason for using the multiplexer 413 is that this process is unnecessary in subsequent operations when acquiring synchronization. In addition, by using the multiplexer, the initial synchronization acquisition process can be selectively selected according to the channel environment.

5 is a block diagram illustrating the post-processing unit 411 of FIG. 4 in detail.
Referring to FIG. 5, the post processor 411 compares a half slot storage unit 501 which stores a detection position of a preamble with a currently received half slot number and a previously stored half slot number. Comparator for outputting the preamble for configuration.

The half slot storage unit 501 powers on an initial terminal and enters a synchronization acquisition process. At this time, when the preamble is detected from the detector 409, the half slot number of the detected point is stored in the buffer. The storing process only performs writing a half slot number into the set buffer. Here, the buffer has a size capable of storing half slot numbers for all preambles generated within 256 x 2 = 512 slots. The buffer is implemented by updating the currently stored half slot number to a new half slot number after storing the half slot number of the corresponding size. If the saving or updating of the half slot number for a particular block is made, the process proceeds to storing or updating the half slot number for the next block of the buffer.

After the half slot number for the detected preamble is stored, the comparator 503 receives and compares the stored value with the previously stored half slot number. As a result of the comparison, if the same value means that the preamble is detected at the same position within the 256 slots, it can be determined that the preamble is detected at the correct position.

Therefore, if there is no identical value as a result of the comparison, the next preamble is detected. If there is an identical value, the preamble for setting the system time at the current position is output.

6 is a flowchart illustrating a system time setting method according to an exemplary embodiment of the present invention.
Referring to FIG. 6, the detector 409 of the terminal determines whether the initial synchronization acquisition process is performed in step 601. In the case of the synchronization acquisition process, the flow proceeds to step 603 to set MUX_EN to '1' in order to use the system setting method of the present invention. However, if it is not a synchronization acquisition process, it is determined as a data reception process and MUX_EN is set to '0' as in step 613.

Accordingly, in the case of the synchronization acquisition process, the UE detects the preamble in step 605. If the preamble is detected, the half slot storage unit stores the half slot number at the moment detected in step 607. The comparator 503 then checks whether there is an identical value among the stored half slot numbers in step 609. If there is no identical half slot number, steps 605 to 609 are repeated. However, if there is the same half slot number, it is determined that the preamble is detected at the correct position and the system time is set as the preamble of the current half slot number as in step 611. Thereafter, the terminal sets the MUX_EN '0' as in step 613 to inform the data receiving process after setting the system time so that the post processor 411 does not operate.

7 is a view showing the worst case in the system setting method of the present invention.
Referring to FIG. 7, the worst case is that the preamble is not detected at the normal position in the S1 section, which is the first 256 slots, and only a false alarm occurs at the point 701, and the preamble is detected at the normal position 703 in the next S2 section. It became. In this case, false alarms are generated and a preamble is detected at the normal position 707 of the S3 section.

Since the false alarm will not occur in 256 slots as in the assumption of the present invention, the half-number is stored at the three preamble detection positions 701, 703, and 705, and the preamble is detected at the last normal position 707. If the previous half slot number is compared with the current value, the same value will come out. Therefore, the system time is set at the current preamble detection position 707. In this case the maximum time required is 256 x 2 = 512 slots.

In the worst case of the prior art, it takes 256 x 3 = 768 slots to set the system time in the synchronization acquisition process. On the contrary, when applying the system time setting method of the present invention, since only a maximum of 512 slots need to be waited, a time gain of about 426 ms can be obtained in the process of receiving a control channel packet.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but is capable of various modifications within the scope of the invention. Therefore, the scope of the present invention should not be limited by the described embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

As described above, the system time setting method of the present invention can reduce the synchronization acquisition time as compared to the prior art, thereby reducing the entry time into the idle state due to other modes as in the composite terminal. In addition, since the present invention only needs to perform a simple operation of storing and comparing the detection of the preamble generated in hardware, it can be easily implemented in software.

Claims (10)

In the method of setting the system time in a terminal of a mobile communication system supporting a hybrid terminal, A first step of detecting a preamble by receiving a control packet signal from a base station in an initial synchronization acquisition step; A second storing the position information of the detected preamble, checking whether the detected preamble is a correct preamble based on the position information of the previously detected and stored preamble, and outputting information on the detected preamble Process, And a third process of determining whether to use information on the output preamble according to whether initial synchronization is acquired. The method of claim 1, wherein the second process comprises: Storing location information of the detected preamble; Checking whether there is a preamble having a predetermined difference value from the position information of the detected preamble among the position information of the previously detected and stored preamble, And if there is a preamble having the detected position information of the preamble and the predetermined difference value, the process of outputting information on the detected preamble. The method of claim 2, wherein the second process comprises: If there is no preamble having the position information of the detected preamble and the predetermined difference value, the position information of the detected preamble is stored instead of the position information of the previously detected and stored preamble. And further comprising performing the first process. 3. The method of claim 2, And the position information of the detected or previously detected and stored preamble is a half slot number corresponding to the detected position of the detected or previously detected and stored preamble. 3. The method of claim 2, And the difference value is 256 slots. An apparatus for setting a system time in a terminal of a mobile communication system supporting a hybrid terminal, A detector for detecting a preamble by receiving a control packet signal from a base station in an initial synchronization acquisition process; A post-processing unit which stores the position information of the detected preamble, and checks whether the detected preamble is a correct preamble based on the position information of the previously detected and stored preamble and outputs information on the detected preamble Wow, And a multiplexer for determining whether to use information on the output preamble according to whether initial synchronization is obtained. The method of claim 6, wherein the post-processing unit, A storage unit which stores location information of the detected preamble, Check whether there is a preamble having a predetermined difference value from the position information of the detected preamble among the position information of the previously detected and stored preamble, and determine the position information of the detected preamble and the predetermined And a comparator for outputting information on the detected preamble if a preamble having a difference value exists. The method of claim 7, wherein the storage unit, If there is no preamble having the position information of the detected preamble and the predetermined difference value, the position information of the detected preamble is stored in place of the position information of the previously detected and stored preamble. System time setting device characterized by. 8. The method of claim 7, And the position information of the detected or previously detected and stored preamble is a half slot number corresponding to the detected position of the detected or previously detected and stored preamble. 8. The method of claim 7, And the difference value is 256 slots.

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