KR100713372B1 - Synchronization acquisition device and method in mobile communication system - Google Patents

Abstract

An apparatus and method are disclosed for capturing initial synchronization when a terminal of a mobile communication system is powered on. The terminal of the present invention can provide its own location information to the base station controller (BSC). The terminal also stores information of neighboring base stations in its own memory. When the power is turned on, the position of the terminal is determined, and the controller of the terminal accesses the memory to find the PN offset of the base station transceiver (BTS) closest to the position of the terminal to perform synchronization acquisition using this information. The neighbor base station information may be stored in a database provided in a base station controller (BSC). In this case, the PN offset of the closest base station transceiver (BTS) may be transmitted through another network network (eg, FM network) other than the CDMA network. It is provided from the base station controller (BSC) to the terminal.

Initial Sync Acquisition, PN Sequence, Nearby Base Station Information, Near Base Station

Description

Acquisition device and method of initial synchronization in mobile communication system {SYNCHRONIZATION ACQUISITION DEVICE AND METHOD IN MOBILE COMMUNICATION SYSTEM}             

1 is a block diagram of a mobile communication system including an initial synchronization capture device according to a first embodiment of the present invention.

2 is a process flow diagram of an initial synchronization acquisition operation according to the first embodiment of the present invention.

3 is a block diagram of a mobile communication system including an initial synchronization capture device according to a second embodiment of the present invention;

4 is a process flow diagram of an initial synchronization acquisition operation according to the second embodiment of the present invention.

The present invention relates to a mobile communication system, and more particularly, to an apparatus and method for capturing initial synchronization when a terminal is powered on.

In general, a code division multiple access (CDMA) mobile communication system includes a base station consisting of a base transceiver station (BTS) and a base station controller (BSC) and a terminal (mobile station). Is done. Each base station has a different pilot pseudo noise (PN) sequence offset to distinguish the forward CDMA channel. The offset refers to the chip unit distance from the pilot PN sequence having offset 0, and the pilot channel of each base station transmits a 32768 chip period PN sequence having a unique offset index value between 0 and 511. In this case, the offset index multiplied by 64 becomes the offset of the base station.

Meanwhile, in the existing IS-95, in order to demodulate a received signal, it is necessary to acquire a frequency and a phase of a carrier and a synchronization for a PN sequence. If the initial frequency error is relatively small, the synchronization process first acquires PN synchronization and then proceeds in order of obtaining carrier frequency and phase synchronization. Typically, the PN synchronization process is divided into PN Acquisition and PN Tracking. In the CDMA demodulator, a searcher is responsible for PN acquisition and a demodulating finger is responsible for PN tracking. PN acquisition is to match roughly the timing between the PN sequence of the spread spectrum signal received and the locally generated PN sequence. At this time, the test is performed in full acquisition mode to synchronize the synchronization within one chip.

However, if the acquisition is not successful even after the elapse of 15 seconds (T _20m ), since the terminal transitions to the initial state and starts again from the initial process, the time required for initial synchronization acquisition becomes longer. There is this. In addition, there is a disadvantage that the processing load of the terminal is increased by such unnecessary processing. In the initial synchronization acquisition process, more efficient synchronization acquisition may be performed by providing base station (BTS) information around the current terminal to the terminal.

Accordingly, an object of the present invention is to provide an apparatus and method for enabling faster initial synchronization acquisition in a CDMA mobile communication system.

Another object of the present invention is to provide an apparatus and method for shortening the time required for a terminal of a CDMA mobile communication system to capture initial synchronization.

It is another object of the present invention to provide an apparatus and method for enabling efficient demodulation of a received signal by reducing the time required for initial synchronization acquisition in a CDMA mobile communication system.

Another object of the present invention is to provide an apparatus and method for removing unnecessary processing load in a terminal of a CDMA mobile communication system.

The terminal of the present invention to achieve these objects can provide its location information to the base station controller (BSC). The terminal also stores information of neighboring base stations in its own memory. When the power is turned on, the position of the terminal is determined, and the controller of the terminal accesses the memory to find the PN offset of the base station transceiver (BTS) closest to the position of the terminal to perform synchronization acquisition using this information. The neighbor base station information may be stored in a database provided in a base station controller (BSC). In this case, the PN offset of the closest base station transceiver (BTS) may be transmitted through another network network (eg, FM network) other than the CDMA network. It is provided from the base station controller (BSC) to the terminal.

According to the first aspect of the present invention, an initial synchronization capturing apparatus of a mobile communication system includes a memory storing position information of neighboring base stations, and a position of the nearest neighbor base station using current position information when the power is turned on. And a controller for acquiring synchronization by obtaining a PN offset of the found neighbor base station.

An initial synchronization capturing apparatus of a mobile communication system according to a second aspect of the present invention includes a terminal for providing its current location information and a database storing location information of neighboring base stations, and when the power is turned on. A base station that finds the nearest neighbor base stations from the database using the current location information provided by the base station and transmits the PN offsets of the base stations to the terminal, the terminal using the transmitted PN offset to capture synchronization. It features.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Terms to be described later are defined in consideration of functions in the present invention, which may vary according to the intention or custom of the user or chip designer, and the definitions should be made based on the contents throughout the present specification.

First, the present invention basically assumes that the terminal can provide its own location information to the base station controller (BSC). Here, the terminal can check its own location information because it has a GPS (Global Positioning System) receiver. The present invention proposes a method according to two embodiments in order to use information of neighboring base stations for initial synchronization acquisition. According to the first embodiment of the present invention, the terminal stores the information of the neighbor base station in its own memory. When the power is turned on, the position of the terminal is determined, and the controller of the terminal, that is, the central processing unit (CPU), accesses its own memory to find the PN offset of the base station transceiver (BTS) closest to the position of the terminal and uses this information. Will perform sync capture. For operation according to the second embodiment of the present invention, it is assumed that a terminal can demodulate data transmitted by a base station controller (BSC) through another network network (for example, an FM network) other than a CDMA network. A configuration of an initial synchronization capturing apparatus according to a first embodiment of the present invention is shown in FIG. 1, and a processing flow of an operation performed at this time is shown in FIG. 2. The configuration of the initial synchronization capturing apparatus according to the second embodiment of the present invention is shown in FIG. 3, and the processing flow of the operation performed at this time is shown in FIG. 4. The configuration and operation of the initial synchronization capturing apparatus according to each embodiment will be apparent from the following description.

In the present invention, for initial synchronization acquisition, the basic concept is that the terminal uses the current location information of the terminal. Here, the current location information of the terminal may be the exact location of the terminal or may be a location parameter for extracting the exact location, although not the exact location. The current location information of the terminal is possible by the GPS receiver provided inside the terminal. In the present invention, the location information of the BTS is stored in a memory in the terminal itself (the first embodiment), and the location information of the BTS is transferred to a network other than the CDMA network in the BSC. The basic concept is a method in which information is transmitted to a terminal and used for initial synchronization acquisition (second embodiment). In the present invention, the conventional UE performs a PN acquisition process using information of neighbor base stations sent from the base station before the call drop to re-acquisition the PN during a call drop. In the initial terminal synchronization acquisition, the synchronization acquisition time can be shortened by providing information of neighboring base stations of the terminal.

1 is a block diagram of a mobile communication system including an initial synchronization capturing apparatus according to a first embodiment of the present invention.

Referring to FIG. 1, location information and PN offsets of neighboring base stations BTS1 to BTSn are stored in a memory provided in the terminal 100. The location information is obtained by the GPS receiver. The terminal 100 can provide its current location information when the power is turned on.

2 is a diagram illustrating a processing flow of an initial synchronization acquisition operation according to the first embodiment of the present invention.

Referring to FIG. 2, when the terminal is powered on (POWER-ON) (step 200), before entering the initial synchronization capturing mode, there is a memory in which accurate location information and PN offset of BTSs are stored inside the terminal. The CPU of the terminal finds the closest BTS using a search algorithm that finds the BTS closest to the position of the BTS using the current terminal position (steps 210 and 220). The terminal acquires the PN offset of the BTS (step 230), and uses the acquired PN offset in the initial synchronization acquisition mode (step 240). This makes capturing sync faster and easier with traditional full sync capture mode. Here, the algorithm for selecting the BTS closest to the location of the current terminal is an algorithm for finding the distance between the terminal and the BTS and finding up to three BTSs that are the smallest distances. This is because a maximum of three BTSs to be selected are needed when the terminal is in three cell handoff areas.

3 is a block diagram of a mobile communication system including an initial synchronization capture device according to a second embodiment of the present invention.

Referring to FIG. 3, location information and PN offsets of neighboring base stations BTS1 to BTSn are stored in a database provided in the BSC 120 of the base station. The terminal 100 may provide its current location information to the BSC 120 through the BTS 110 when the power is turned on.

4 is a diagram illustrating a processing flow of an initial synchronization capturing operation according to a second embodiment of the present invention.

4, when the power is turned on (step 300), the terminal 100 can know its current location information (step 310), and transmits the location information to the BSC 120 through the BTS 110 (step 320). ). Then, since the BSC 120 has accurate location information of each BTS as a database, the BSC 120 transmits the PN offsets of the BTSs closest to the current location of the terminal 100 to the terminal (step 330). The terminal performs a synchronization acquisition process using the transmitted PN offset (step 340). Since the information of the neighbor base stations transmitted from the BSC 120 to the terminal 100 cannot use the CDMA network, the BSC 120 and the terminal 100 transmit and receive signals through other networks (for example, the FM network). Should be performed.

For reference, the conventional method acquires synchronization by sequentially performing all tests for the 32786 chip cycle, but the initial synchronization acquisition operation according to an embodiment of the present invention uses the information of neighboring base stations to reduce the time required for acquisition. You can save.

As described above, the present invention can greatly reduce the time required for the existing full synchronization acquisition operation by obtaining the information of the neighboring base stations from the base station using the location information of the terminal and using the information for initial synchronization acquisition. In addition, unnecessary processing load of the terminal can be reduced accordingly.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described. However, various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

Claims (16)

In the initial synchronization capture device of the terminal in a mobile communication system, A memory that stores location information of neighboring base stations and PN offset values of each base station; A Global Positioning System (GPS) receiver that calculates its current position from the satellite, And a controller for searching for a location of the nearest neighbor base station using the current location information and a search algorithm when the power is turned on, and acquiring a PN offset of the searched neighbor base station to capture synchronization. Initial sync capture device. The apparatus of claim 1, wherein the number of neighbor base stations searched is maximum 3. The apparatus of claim 1, wherein the location information of the neighboring base station is location information of a base station transceiver (BTS). In the initial synchronization capture device of the mobile communication system, A terminal providing its current location information, It has a database that stores the location information of the neighboring base station, when the power is turned on using the current location information provided from the terminal to find the nearest neighbor base station from the database and transmits the PN offset of the base stations to the terminal Includes a base station, And the terminal captures sync using the transmitted PN offset. The initial synchronization capture device of claim 4, wherein the location information of the neighboring base station is location information of a base station transceiver (BTS). 5. The initial synchronization acquisition device as claimed in claim 4, wherein the number of neighbor base stations found is at most three. The initial synchronization capture device of claim 4, wherein the found PN offsets of neighboring base stations are provided from the base station controller to the terminal through a network other than a CDMA network. 8. The initial synchronization capture device as claimed in claim 7, wherein the found PN offsets of neighboring base stations are provided from the base station controller to the terminal through an FM network. In the initial synchronization capture method of a terminal including a Global Positioning System (GPS) receiver in a mobile communication system, Calculating current location information by using the GPS receiver when the power is turned on; Searching for the location of the nearest base station using the current location information; And acquiring synchronization by acquiring a PN offset of the found neighbor base station. 10. The method of claim 9, wherein the number of neighbor base stations searched is maximum 3. The method of claim 9, wherein the location information of the neighboring base station is location information of a base station transceiver (BTS). In the initial synchronization capture method of the mobile communication system, When the power is turned on, the terminal including the Global Positioning System (GPS) receiver provides its current location information to the base station, Finding nearest neighbor base stations from a database storing location information of neighboring base stations using the current location information provided from the terminal in the base station; Transmitting, by the base station, PN offsets of the found neighbor base stations to the terminal; And acquiring, by the terminal, synchronization using the transmitted PN offset. The method of claim 12, wherein the location information of the neighboring base station is location information of a base station transceiver (BTS). 13. The method of claim 12, wherein the number of neighbor base stations found is at most three. The method of claim 12, wherein the found PN offsets of neighbor base stations are provided from the base station controller to the terminal through a network other than a CDMA network. 16. The method of claim 15, wherein the found PN offsets of neighboring base stations are provided from the base station controller to the terminal via an FM network.

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