KR20100027291A - Apparatus and method for frequency plan to setting frequency bandwidth in mobile communication system - Google Patents

Abstract

PURPOSE: A frequency plan apparatus for setting a frequency bandwidth in a mobile communication system and a method thereof are provided to reduce interference according to a frequency schedule of an existing mobile communication system. CONSTITUTION: Bandwidth determining methods of a broadcasting channel and a synchronization channel are selected(305). A frequency bandwidth is set through the selected bandwidth determining method(307). The frequency reuse rate of a frequency bandwidth is determined(309). The location of the frequency bandwidth according to the frequency reuse rate is determined(311).

Description

Frequency planning apparatus and method for setting frequency bandwidth in mobile communication system {APPARATUS AND METHOD FOR FREQUENCY PLAN TO SETTING FREQUENCY BANDWIDTH IN MOBILE COMMUNICATION SYSTEM}

The present invention relates to an apparatus and a method for setting a bandwidth between a base station and a terminal in a mobile communication system. In particular, the bandwidth and broadcast channel and synchronization of the base station in a mobile communication system in which the base stations having different bandwidths and the terminals having different bandwidths are mixed. A frequency planning apparatus and method for efficiently setting a frequency position of a channel.

In a typical CDMA cellular 3GPP system, system information is transmitted to a terminal in a base station using a broadcasting channel (BCH) that broadcasts the entire base station coverage.

The broadcast channel and the synchronization channel (SCH) are a bandwidth and frequency positions of the broadcast channel and the synchronization channel in a mobile communication system in which base stations having different bandwidths and terminals having different bandwidths are mixed. As the important information for determining whether to connect and handover scheme, it is important to design the broadcast channel and the synchronization channel.

In 3GPP LTE, the bandwidth of the terminal is fixed to 20 MHz, and the bandwidth of the base station can be set to various bandwidths of 1.4 to 20 MHz according to the efficiency of the base station in consideration of a system that can coexist in various ways from 1.4 to 20 MHz. .

In this case, the bandwidth of the broadcast channel and the synchronization channel is always set to 1.4 MHz regardless of the bandwidth of the base station, and the frequency position is always set to the center portion of the entire band, so that the measurement of neighboring cells is easy and easy for handover. Provide advantages.

1 is a diagram illustrating a broadcast channel and a synchronization channel designed in general LTE.

Referring to FIG. 1, as described above, the bandwidths of the broadcast channel and the synchronization channel are always set to 1.4 MHz regardless of the bandwidth of the base station, and the frequency position is always set to the center portion of the entire band.

That is, the broadcast channel and the synchronization channel of the base station 101 supporting the bandwidth of 1.4MHZ, the base station 103 supporting the bandwidth of 10MHZ, the base station 105 supporting the bandwidth of 20MHZ are always 1.4MHz and the position of the frequency Is located in the middle of the entire band of the base stations.

When the frequency positions of the broadcast channel and the sync channel are the same as described above, when the broadcast channel and the sync channel are received in one cell, the broadcast channel and the sync channel are received due to the interference of the broadcast channel and the sync channel of another cell. The range is limited, and there is a problem in that resource waste occurs for portions other than the positions of the broadcasting channel and the synchronization channel existing in the intermediate position of the entire frequency band.

In addition, there is a disadvantage that the bandwidth supported by the terminal of the 3GPP LTE system does not support the maximum bandwidth of the fixed base station.

SUMMARY OF THE INVENTION The present invention has been derived to solve the above problems, and an object of the present invention is to provide a bandwidth and a broadcast channel and a synchronization channel of a base station in a mobile communication system in which base stations having different bandwidths and terminals having different bandwidths are mixed. The present invention provides a frequency planning apparatus and method for efficiently setting frequency positions.

Another object of the present invention is to provide an apparatus and method for setting a bandwidth of a base station and a frequency position of a broadcast channel and a synchronization channel orthogonal to an adjacent base station in a mobile communication system in which base stations having different bandwidths and terminals having different bandwidths are mixed. In providing.

According to a first aspect of the present invention for achieving the above objects, the frequency planning apparatus for setting the frequency bandwidth in the mobile communication system to set the transmission band of the base station of each cell using the capacity of the channel required in each cell And a frequency band controller configured to set the position of the frequency band used in each cell, that is, the frequency position of the synchronization channel and the broadcasting channel, by using the position of the frequency band used in the adjacent cell.

According to a second aspect of the present invention for achieving the above objects, the frequency planning method for setting the frequency bandwidth in the mobile communication system to identify the capacity of the channel required in each cell and the position of the frequency band used in the adjacent cell And a transmission band of the base station of each cell using the capacity of the channel required by each cell, and a frequency used by each cell by using the location of the frequency band used by the adjacent cell. And setting the position of the band, that is, the frequency position of the synchronization channel and the broadcast channel.

As described above, the present invention checks the position of a frequency used in an adjacent cell and performs a frequency plan for setting a position of a broadcast channel and a synchronization channel at a position orthogonal to the identified position, thereby making a frequency plan of an existing mobile communication system. Can reduce interference and prevent resource waste due to the location of the existing fixed frequency band.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when 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.

In the following description, a frequency planning apparatus and method for efficiently setting a bandwidth of a base station and frequency positions of a broadcasting channel and a synchronization channel in a mobile communication system in which base stations having different bandwidths and terminals having different bandwidths are mixed will be described.

As described above, in order to perform the frequency plan according to the present invention, it is assumed that the mobile communication system satisfies the following conditions.

1, regardless of bandwidth, the terminal should receive the SCH and BCH of the base station and access the base station to receive the service. That is, all terminals should be able to receive SCHs and BCHs transmitted by various base stations having different bandwidths regardless of their bandwidths.

2, flexible use between partial bands within the entire operator's frequency band. In the case of a cell having a small bandwidth of the base station, the cell boundary performance should be improved by adjusting the frequency reuse factor of the system by adjusting the frequency position of the use band between cells. In addition, in the case of a broadband base station, a narrow band terminal should be able to distribute the load evenly in the entire frequency band of the base station.

3, the frequency positions of the SCH and the BCH should be orthogonal between cells to reduce inter-cell interference and expand the reception range. SCH and BCH are important factors for determining cell coverage and are also important factors for measuring neighboring cells. The reception range of the SCH and the BCH can be extended to extend cell coverage and facilitate neighbor cell measurement for handover.

2 is a block diagram showing a configuration of a base station for setting a transmission and reception bandwidth in a mobile communication system according to an embodiment of the present invention.

Referring to FIG. 2, the base station may include an encoder and a modulator 200, an IF processor 202, an RF processor 204, and a frequency band controller 206.

The code and modulator 200 codes and modulates the bit string to be transmitted to each terminal provided in a corresponding manner.

The frequency band controller 206 determines a bandwidth and a frequency position of a synchronization channel (SCH) and a broadcast channel (BCH). Here, the frequency band controller 206 determines the band of the broadcast channel and the synchronization channel in consideration of the capacity of the channel required in each cell and the position of the frequency band used in the adjacent cell, and uses the capacity of the channel. It is used to set the base station transmission bandwidth of each cell. In addition, the frequency band controller 206 sets the position of the frequency band used in each cell, that is, the frequency position of the sync channel and the broadcast channel, using the position of the frequency band used in the adjacent cell. At this time, the frequency band controller is set to be orthogonal to the frequency band used in the adjacent cells when positioning the frequency band to increase the frequency reuse to reduce interference.

The base station classifies signals of the code and modulator 200, that is, signals to be transmitted to each terminal. That is, the base station classifies the signal to be transmitted according to the frequency band and the frequency position determined by the frequency band controller 206.

The IF processor 202 may include a DAC and an IF filter. The signal to be transmitted is input to the DAC, converted into an analog signal, and then passed to the IF filter.

The RF processor 204 converts the baseband signal provided from the IF processor 202 into an RF band signal and transmits the RF band signal through an antenna.

The foregoing has described a frequency planning apparatus for efficiently setting a bandwidth of a base station and frequency positions of a broadcast channel and a synchronization channel in a mobile communication system in which base stations having different bandwidths and terminals having different bandwidths are mixed. A frequency planning method for efficiently setting the bandwidth of a base station and the frequency position of a broadcast channel and a synchronization channel in a mobile communication system in which base stations having different bandwidths and terminals having different bandwidths are mixed using the apparatus according to the present invention. something to do.

3 is a flowchart illustrating a process of setting a frequency bandwidth in a base station according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the base station determines bandwidth and frequency positions of a synchronization channel (SCH) and a broadcast channel (BCH), which are important factors for determining whether a terminal accesses a base station and a handover method. Follow the process.

In order to perform the above process, the base station first checks the channel information in step 301 to identify the location of the frequency band used in the adjacent cell, and then proceeds to step 303 to use the adjacent channel using the checked information. Check the frequency band.

In step 305, the base station selects a band determination method for the broadcast channel and the synchronization channel.

Here, the band determination method of the broadcast channel and the synchronization channel is selected in consideration of the capacity of the channel required in each cell and the position of the frequency band used in the adjacent cell, the capacity of the channel is the transmission bandwidth of the base station of each cell Used to set In addition, the position of the frequency band used in the adjacent cell is used to set the position of the frequency band used in each cell, that is, the frequency position of the synchronization channel and the broadcast channel. Here, the position of the frequency band is set to be orthogonal to the frequency band used in adjacent cells to increase the frequency reuse to reduce interference.

The band determination method of the broadcast channel and the synchronization channel may be classified according to a frequency band supported by the coexisting terminal. For example, assuming that the co-existing terminals support 5 MHz, 10 MHz, and 20 MHz, the method for determining the bandwidth of the broadcast channel and the synchronization channel is based on a bandwidth of 5 MHz, a method based on a bandwidth of 10 MHz, and It can be classified into a method based on a bandwidth of 20 MHz.

Thereafter, the base station proceeds to step 307 to set the frequency bandwidth in the band determination method selected in step 305.

In step 309, the base station determines the frequency reuse rate of the frequency band. In step 311, the base station determines the location of the frequency band according to the frequency reuse rate.

Here, the base station must satisfy the following conditions in order to set the frequency bandwidth.

First, the bandwidth of the sync channel and the broadcast channel of each cell should be set to the minimum bandwidth of the base station or the terminal so that the transmission resources of the sync channel and the broadcast channel become the minimum bandwidth of the base station or the terminal.

Secondly, the frequency positions of the sync channel and the broadcast channel are present in the base station bandwidth of the cell, respectively, and should be present in the frequency interval obtained by dividing the corresponding base station bandwidth by the minimum bandwidth unit.

Third, the frequency positions of the sync channel and the broadcast channel are determined according to the positions of the sync channel and the broadcast channel of the adjacent cell. (Receive ranges of the sync channel and the broadcast channel by setting orthogonal to the sync channel and the broadcast channel of the adjacent cells. Expand.)

Fourth, the sync channel and the broadcast channel may exist simultaneously in one or more frequency sections and may exist simultaneously in all frequency sections. (The number of frequency sections in which the sync channel and the broadcast channel exist is determined according to the bandwidth of a dominant terminal among coexisting terminals.)

If the base station selects a method for determining the band of the broadcast channel and the synchronization channel based on the bandwidth of 5MHz in step 305, assuming that there is a base station supporting the bandwidth of 5MHz, 10MHz, 20MHz, The base station is configured to configure the bandwidth of 10MHz to the bandwidth of two 5MHz, and the bandwidth of 20MHz to the bandwidth of four 5MHz based on the 5MHz bandwidth. In this case, the frequency reuse rate corresponding to the area of the broadcasting channel and the synchronization channel of the base station having the bandwidth of 20 MHz and the data area is 1, and the area of the broadcasting channel and the synchronization channel of the base station having the bandwidth of 10 MHz and the data area. The corresponding frequency reuse rate is 2, and the frequency reuse rate corresponding to the area of the broadcasting channel and the synchronization channel and the data area of the base station having the bandwidth of 5 MHz is 4.

On the other hand, when the base station selects a method for determining the band of the broadcast channel and the synchronization channel based on the bandwidth of 10MHz in step 305, assuming that there is a base station supporting the bandwidth of 5MHz, 10MHz, 20MHz, For efficient connection of terminals supporting 10MHz band, when the base station bandwidth is 10MHz or 20MHz, the region of the sync channel and broadcast channel is allocated by 10MHz, and the frequency positions of the sync channel and broadcast channel are orthogonal in two adjacent cells. To reduce the occurrence of interference.

At this time, the frequency reuse rate of the data area of the base station having a bandwidth of 20 MHz is 1, the frequency reuse rate of the broadcast channel and the synchronization channel area is 2. In addition, the frequency reuse rate of the data area of the base station having a bandwidth of 10 MHz becomes 2, and the frequency reuse rate of the synchronization channel and broadcast channel areas becomes 4.

In addition, when the base station selects a method of determining the band of the broadcast channel and the synchronization channel based on the bandwidth of 20MHz in step 305, assuming that there is a base station supporting the bandwidth of 5MHz, 10MHz, 20MHz, For efficient connection of a terminal supporting a 20 MHz band, when the base station bandwidth is 20 MHz, an area of the sync channel and a broadcast channel is allocated, and interference is generated by orthogonally setting the frequency positions of the sync channel and the broadcast channel in adjacent cells. To reduce

At this time, the frequency reuse rate of the data area of the base station having a bandwidth of 20 MHz becomes 1, and the frequency reuse rate of the broadcast channel and sync channel area becomes 4. In addition, the frequency reuse rate of the data area of the base station having a bandwidth of 10 MHz becomes 2, the frequency reuse rate of the sync channel and the broadcast channel area becomes 4, the data area of the base station having a bandwidth of 5 MHz and the synchronization channel and The frequency reuse rate of the broadcast channel region is four.

As described above, the method of determining the positions of the frequency band, the broadcast channel, and the synchronization channel will be described in detail with reference to FIGS. 4 to 7.

The base station then terminates this algorithm.

4 is a diagram illustrating a process of determining a band of a broadcast channel and a synchronization channel based on a bandwidth of 5 MHz in a base station according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the base station selects a method for determining the band of the broadcast channel and the synchronization channel based on a bandwidth of 5 MHz, and assumes that a base station supporting a bandwidth of 5 MHz, 10 MHz, and 20 MHz exists. to be.

Accordingly, the base station configures a bandwidth of 10 MHz as two 5 MHz bandwidths and a bandwidth of 20 MHz as four 5 MHz bandwidths based on the 5 MHz bandwidth. In this case, the frequency reuse rate corresponding to the area of the broadcasting channel and the synchronization channel of the base station having the bandwidth of 20 MHz and the data area is 1, and the area of the broadcasting channel and the synchronization channel of the base station having the bandwidth of 10 MHz and the data area. The corresponding frequency reuse rate is 2 (every 10 MHz), and the frequency reuse rate corresponding to the broadcast channel and synchronization channel and data areas of the base station having the bandwidth of 5 MHz is 4 (every 10 MHz).

5 is a diagram illustrating an example of setting a frequency band in a base station according to the present invention.

Referring to FIG. 5, when the bandwidth supported by the base station is 5/10/20 MHz, the frequency band positions of the 5 MHz base station can be determined by four types according to the cell plan, and the frequency band positions of the 10 MHz base station. Can be set to two types.

In this case, the base station properly arranges each type of cells to set the frequency band between adjacent cells orthogonally, and includes a synchronization channel and a broadcast channel in all frequency sections of 5 MHz units within the base station bandwidth to support a 5 MHz band. The terminal may access all frequency intervals within the base station bandwidth and may distribute the load between the frequency intervals by adjusting the amount of the terminal accessed by the base station in each frequency interval.

6 is a diagram illustrating a process of determining the bands of the broadcast channel and the synchronization channel based on a bandwidth of 10MHz in a base station according to an embodiment of the present invention.

Referring to FIG. 6, the base station selects a method of determining a band of the broadcast channel and a synchronization channel based on a bandwidth of 10 MHz, and assumes that a base station supporting a bandwidth of 5 MHz, 10 MHz, and 20 MHz exists. to be.

Accordingly, the base station allocates an area of the synchronization channel and the broadcast channel by 10 MHz when the base station bandwidth is 10 MHz or 20 MHz for efficient access of a terminal supporting a band of 10 MHz, and the synchronization channel and the broadcast channel in two adjacent cells. Set the frequency position of orthogonally to reduce interference.

In this case, the frequency reuse rate of the data area of the base station having a bandwidth of 20 MHz is 1, and the frequency reuse rate of the broadcast channel and the synchronization channel area is 2 (5 MHz unit based on 10 MHz). In addition, the frequency reuse rate of the data area of the base station having a bandwidth of 10 MHz becomes 2 (10 MHz units), and the frequency reuse rate of the sync channel and broadcast channel areas becomes 4 (5 MHz units).

7 is a diagram illustrating a process of determining a band of the broadcast channel and the synchronization channel based on a bandwidth of 20 MHz in a base station according to an embodiment of the present invention.

Referring to FIG. 7, the base station selects a method of determining a band of the broadcast channel and a synchronization channel based on a bandwidth of 20 MHz, and assumes that a base station supporting a bandwidth of 5 MHz, 10 MHz, and 20 MHz exists. to be.

Accordingly, the base station allocates an area of the synchronization channel and the broadcast channel when the base station bandwidth is 20 MHz for efficient access of the terminal supporting the 20 MHz band supporting the 20 MHz band, and the synchronization channel and the broadcast in the adjacent cells. Set the frequency position of the channel to be orthogonal to reduce the occurrence of interference.

In this case, the frequency reuse rate of the data area of the base station having a bandwidth of 20 MHz is 1, and the frequency reuse rate of the broadcast channel and the synchronization channel area is 4 (5 MHz unit). In addition, the frequency reuse rate of the data area of the base station having a bandwidth of 10 MHz becomes 2 (5 MHz units based on 10 MHz), and the frequency reuse rate of the synchronization channel and broadcast channel areas becomes 4, and the base station has a bandwidth of 5 MHz. The frequency reuse rate of the data region and the sync channel and broadcast channel region is 4 (5 MHz unit).

When the band is determined as shown in FIGS. 6 and 7, cells of each type are arranged as shown in FIG. 5 so that frequency bands between adjacent cells are orthogonal to extend the reception range of the synchronization channel and the broadcast channel. have.

8 is a flowchart illustrating an operation process of a portable terminal performing a handover process using an allocated frequency bandwidth according to an exemplary embodiment of the present invention.

The operation of the portable terminal will be described with reference to a method for measuring a neighbor cell according to a feature in which the allocated frequency bandwidth is different for each cell and the positions of the synchronization channel and the broadcasting channel are different according to the present invention.

Referring to FIG. 8, it will be described on the assumption that the portable terminal satisfies a condition for performing a handover process.

After checking the bandwidth of the entire base station in step 801, the portable terminal proceeds to step 803 to compare the bandwidth of the portable terminal with the bandwidth of the base station.

The process of comparing the bandwidth of the portable terminal with the bandwidth of the base station is a criterion for selecting a method of measuring an adjacent cell. Accordingly, the portable terminal performs a method of measuring a broadcast channel and a synchronization channel outside the bandwidth of the portable terminal or a method of measuring a broadcast channel and a synchronization channel of an adjacent cell according to the result of the process.

In step 805, the portable terminal checks the result of the process of step 803.

If the bandwidth of the portable terminal is not equal to the bandwidth of the base station in step 805, that is, if the bandwidth supported by the portable terminal to perform the handover process is smaller than the bandwidth of the base station, the portable terminal proceeds to step 813. Proceed to the process of measuring the broadcast channel and the synchronization channel out of the bandwidth supported by the portable terminal (inter-frequency scan).

On the other hand, if the bandwidth of the portable terminal is the same as the bandwidth of the base station in step 805, the portable terminal proceeds to step 807 by using a signal in a frequency band given to the adjacent cell always regardless of the bandwidth of the portable terminal Measure adjacent cells.

In step 809, the portable terminal determines whether a handover process is necessary using the measured information.

If the handover process is not necessary, the portable terminal performs the process of step 801 again.

On the other hand, if the handover process is needed, the portable terminal proceeds to step 811 to perform the handover process and ends the present algorithm.

Since the frequency plan of the mobile communication system according to the present invention as described above is not fixed to the standard, the portable terminal does not grasp and operate all the frequency plan information of the system in advance, but accesses the base station to the frequency plan information of the system. In addition, bandwidth and frequency position information of the data region and the SCH / BCH region should be identified.

In the method of confirming the frequency plan information in the portable terminal, the portable terminal receives the synchronization channel, establishes synchronization with the base station, and then receives the broadcast channel message to obtain the frequency plan information. In this case, the frequency planning information included in the BCH is used by the size of the entire frequency band (operator specific information) used by the operator, the size and frequency location of the frequency band used by the base station (cell specific information), and used by the corresponding base station within the system-wide frequency. Relative position of frequency, SCH / BCH frequency position (cell specific information) transmitted by corresponding base station, relative SCH / BCH frequency position within base station bandwidth

(Eg, information indicating whether SCH / BCH exists for partial bands in a base station bandwidth (0101 for a 20 MHz type 2 base station: 01 for a 10 MHz type 2 base station: 01)).

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible 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 the equivalents of the claims.

1 is a diagram illustrating a broadcast channel and a synchronization channel designed in general LTE,

2 is a block diagram showing a configuration of a base station for setting a transmission and reception bandwidth in a mobile communication system according to an embodiment of the present invention;

3 is a flowchart illustrating a process of setting a frequency bandwidth in a base station according to an embodiment of the present invention;

4 is a diagram illustrating a process of determining a band of a broadcast channel and a synchronization channel based on a bandwidth of 5 MHz in a base station according to an embodiment of the present invention;

5 is a diagram illustrating an example of setting a frequency band in a base station according to the present invention;

6 is a diagram illustrating a process of determining a band of a broadcast channel and a synchronization channel based on a bandwidth of 10 MHz in a base station according to an embodiment of the present invention;

7 is a diagram illustrating a process of determining a band of a broadcast channel and a synchronization channel based on a bandwidth of 20 MHz in a base station according to an embodiment of the present invention;

8 is a flowchart illustrating an operation process of a portable terminal performing a handover process using an allocated frequency bandwidth according to an exemplary embodiment of the present invention.

Claims (2)

In the frequency planning apparatus for setting the frequency bandwidth in the mobile communication system, The transmission band of the base station of each cell is set using the capacity of the channel required in each cell, and the position of the frequency band used in each cell, that is, a synchronization channel and And a frequency band controller for setting the frequency position of the broadcast channel. In the frequency planning method for setting the frequency bandwidth in the mobile communication system, Determining the capacity of the channel required in each cell and the position of the frequency band used in the adjacent cell; Setting a transmission band of a base station of each cell by using a capacity of a channel required for each cell; And setting a position of a frequency band used in each cell, that is, a frequency position of a sync channel and a broadcast channel, by using the position of the frequency band used by the adjacent cell.

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