KR20150015651A - Method and base station for controling multi-carrier communication - Google Patents

Abstract

A method for controlling multi-carrier communications and a base station performing the same are provided to select a frequency in consideration of the case in which spurious wave and interference between adjacent cells are severe in an uplink by including: a step of obtaining spurious wave and cell interference information of the adjacent base station through an interface between base stations; and a step of determining a frequency shift based on the spurious wave and the cell interference information.

Description

[0001] METHOD AND BASE STATION FOR CONTROLLING MULTI-CARRIER COMMUNICATION [0002]

The present invention relates to a multicarrier communication control method and a base station performing the same.

Recently, a multi-carrier LTE (Long Term Evolution) service with a frequency band expanded to two has been launched. A terminal capable of using a multicarrier LTE service can select and connect to one of the optimal bandwidths of data traffic of frequencies of two or more bands. As described above, the multi-carrier LTE service is faster than when only one frequency band is used as the frequency band is increased.

On the other hand, interference occurs due to unwanted emissions of systems using adjacent frequencies (eg, Wi-Fi, TDD systems, other systems, etc.).

Conventionally, there is a matter of selecting a carrier according to a load at the time of a multicarrier, but a method for exchanging information for appropriately responding to interference avoidance by spurious waves in the standard is not described.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a multicarrier communication control method for selecting a frequency in consideration of a case where interference between spurious waves and adjacent cells is severe in an uplink, and a base station performing the same.

According to an aspect of the present invention, there is provided a method for controlling a multicarrier communication in a base station, the method including: obtaining spurious and cell interference information of an adjacent base station through an inter-base station interface; And determining a frequency shift based on the cell interference information.

The spurious and cell interference information may include at least one of:

The uplink received signal strength is included,

Before the exchanging step,

Further comprising the step of the base station measuring an uplink received signal strength,

Wherein the determining comprises:

The frequency shift for multicarrier communication can be determined based on the measured received signal strength of the uplink and the received signal strength of the uplink of the neighbor base station.

Wherein the measuring step comprises:

Measuring a received signal strength in an uplink subframe in which resources are not allocated,

Wherein the uplink received signal strength of the neighbor base station is determined by:

And may be a received signal strength measured in an uplink subframe in which the resource is not allocated.

Wherein the acquiring comprises:

Transmitting a load measurement request message to the neighbor base station, and receiving a load measurement response message to which the spurious and cell interference information is added from the neighbor base station.

Wherein the determining comprises:

If the strength of the uplink received signal strength of the neighbor base station is lower than the measured received signal strength of the uplink, it is possible to determine the movement to the frequency of the neighbor base station.

Wherein the determining comprises:

Determining whether the measured signal strength of the uplink is greater than or equal to a predefined threshold; determining whether a difference between the uplink received signal strength of the neighbor base station and the measured uplink received signal strength Determining whether the hysteresis parameter is greater than or equal to the predefined hysteresis parameter, and if the hysteresis parameter is greater than or equal to the predefined hysteresis parameter, determining a shift to the frequency of the neighbor base station.

According to another aspect of the present invention, a base station includes a measurement unit for measuring spurious waves and cell interference information of a first frequency used by the base station, a spurious and a cell interference information of a second frequency used by an adjacent base station through an inter- And a multicarrier control unit for determining a movement between the first frequency and the second frequency based on the spurious wave and the cell interference information.

Wherein the measuring unit comprises:

Measuring an uplink received signal strength of the first frequency,

The base station communication unit includes:

Acquires an uplink received signal strength of the second frequency,

Wherein the multi-

When the strength of the uplink received signal strength of the first frequency to which the user terminal is connected is higher than the strength of the uplink received signal strength of the second frequency, the user terminal is connected to the user terminal at the second frequency through radio resource connection re- Can be requested.

Wherein the measuring unit comprises:

Measuring an uplink received signal strength of the first frequency in an uplink subframe in which resources are not allocated,

The base station communication unit includes:

The uplink received signal strength of the second frequency measured in the uplink subframe in which the resource is not allocated can be obtained.

The base station communication unit includes:

A load measurement request message may be transmitted to the neighbor base station to receive a load measurement response message to which an uplink received signal strength of the second frequency is added.

Wherein the multi-

Wherein the received signal strength of the uplink of the first frequency is greater than or equal to a predefined threshold and the difference between the received signal strength of the uplink of the neighbor base station and the received signal strength of the measured uplink is greater than or equal to a predefined hysteresis parameter , It may decide to change the frequency to which the user terminal is connected to the second frequency.

According to an embodiment of the present invention, in a multi-carrier environment, when a received signal strength indicator (RSSI) is high due to an unnecessary uplink frequency and interference between neighboring cells, And determines the frequency shift or handover to the target frequency when the RSSI of the target frequency is lower than the RSSI of the serving frequency. Therefore, even if the uplink bandwidth of a specific frequency is high, the performance of the downlink as well as the uplink can be improved even if the unnecessary waves of other systems or interference of adjacent cells are high.

1 is a block diagram of a multi-carrier communication network according to an embodiment of the present invention.
2 is a block diagram illustrating a configuration of a base station according to an embodiment of the present invention.
3 is a flowchart illustrating a multi-carrier communication control method according to an embodiment of the present invention.
4 is a flowchart illustrating an operation of a base station according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

Also, the terms of " part ", "... module" in the description mean units for processing at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software.

In this specification, a terminal includes a mobile station (MS), a mobile terminal (MT), a subscriber station (SS), a portable subscriber station (PSS), a user equipment , An access terminal (UE), an access terminal (AT), and the like, and may include all or some of functions of a mobile terminal, a subscriber station, a mobile subscriber station, a user equipment,

In this specification, a base station (BS) includes an access point (AP), a radio access station (RAS), a node B, an evolved NodeB (eNodeB) A base station (BTS), a mobile multihop relay (MMR) -BS, or the like, and may perform all or a part of functions of an access point, a radio access station, a Node B, an eNodeB, a base transceiver station, .

Reference will now be made to the embodiments of the present invention with reference to the drawings.

1 is a block diagram of a multi-carrier communication network according to an embodiment of the present invention.

1, a multicarrier communication network is an LTE (Long Term Evolution) network providing a multicarrier service, and includes a plurality of base stations 100 and a user terminal 200 connected to a plurality of base stations 100 . Here, although not shown, some of the cells of the first base station 101 and the second base station 103 are co-located, and the user terminal 200 is connected to the first base station 101 or the second base station 103 And uses the communication service.

At this time, the first base station 101 transmits traffic using a first frequency, and the second base station 103 transmits traffic using a second frequency. The user terminal 200 is a terminal supporting the multicarrier service and can be connected at the first frequency or the second frequency.

The base station 1 101 and the base station 2 103 share the base station information using the base station interface (X2 interface), as defined in the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard.

In this case, the plurality of base stations 100 may use an overload indication for requesting less interference from neighboring base stations using load information for uplink interference control, an uplink indication It can support a high interference indication scheme that indicates that it is highly available.

In addition, the plurality of base stations 100 can know the load information of the counterpart base station by exchanging a load measurement request message (Resource Status Request) and a load measurement response message (Resource Status Response). Accordingly, the plurality of base stations 100 distributes the load based on the number of users connected between frequencies and the amount of radio resources (RBs) used. For example, if the radio resource usage of the first frequency is high and the number of users is large, some users can be handed over at the second frequency.

Also, even when the plurality of base stations 100 do not allocate data on the uplink, if the received signal strength indicator (referred to as 'RSSI' hereinafter) of the uplink is higher than a specific threshold value, Or it can be judged that the unnecessary waves of the adjacent band are in a severe state. Therefore, if the RSSI of another frequency is lower than the RSSI of another frequency, the handover or the frequency shift (Redirection) may be performed at the corresponding frequency. do. At this time, the user terminal 200 requests the frequency change through the RRC Connection Reconfiguration (RRC Connection Reconfiguration) command.

Here, a configuration in which a plurality of base stations 100 control multicarrier communication will be described with reference to FIG.

2 is a block diagram illustrating a configuration of a base station according to an embodiment of the present invention.

2, the base station 100 includes a resource allocation unit 110, a measurement unit 130, a base station communication unit 150, and a multicarrier control unit 170.

The resource allocation unit 110 allocates and manages resources in the uplink. And can perform resource deallocation and resource reallocation according to the frequency shift.

The measurement unit 130 measures the RSSI of the uplink of the base station 100. At this time, the RSSI is measured in a subframe in which the UL grant is not allocated, i.e., the UL resource is not allocated. And the measured RSSI is the total size of all received signals, including interference plus thermal noise in addition to the signal.

In addition, the measuring unit 130 may periodically measure the RSSI of the uplink.

The base station communication unit 150 establishes an interface (X2 interface) between the adjacent base station and the base station. (Physical Resource Block (PRB) Usage) and the RSSI information measured by the measurement unit 130 through the inter-base station interface. Unlike the conventional sharing of load information, RSSIs measured in a subframe in which uplink resources are not allocated are additionally shared.

The multicarrier control unit 170 controls the frequency change based on the load distribution considering the load information of the neighbor base stations acquired through the base station communication unit 150.

At this time, the multicarrier control unit 170 calculates the uplink frequency based on the RSSI of the uplink measured by the measurement unit 130 and the RSSI of the uplink of the neighbor base station acquired through the base station communication unit 405 Change it. That is, if the RSSI value of the uplink of the first frequency connected to the current user terminal 200 is equal to or greater than a specific threshold value and the RSSI value of the uplink of the first frequency is the RSSI value of the uplink of the second frequency The mobile station 200 changes the uplink frequency of the user terminal 200 from the first frequency to the second frequency.

Thus, by determining the frequency change based on the RSSI of the uplink, it is possible to avoid the interference of the uplink spurious and adjacent cells in the multicarrier environment.

Hereinafter, the process of controlling the multicast communication by the base station 100 will be described, and the same reference numerals will be used in conjunction with the configurations of FIG. 1 and FIG.

3 is a flowchart illustrating a multi-carrier communication control method according to an embodiment of the present invention.

Referring to FIG. 3, the first and second base stations 101 and 103 measure the uplink received signal strength, which is a resource unallocated state, respectively (S101 and 103). Here, it is assumed that the first base station 101 is a serving base station to which the user terminal 200 is currently connected, and the second base station 103 is a target base station.

The base station communication unit 150 of the first base station 101 transmits a load status request message to the second base station 103 in step S105. And receives a load status response message including the received signal strength R2 of the second base station 103 (S107). Here, steps S105 and S107 may be performed periodically.

The received signal strength R1 of the first base station 101 is included in a load status response message in response to a load status request message transmitted from the second base station 103, (103), and this step is omitted.

The multicarrier controller 170 of the base station 1 101 determines whether the frequency is changed based on the received signal strength R1 measured in step S101 and the received signal strength R2 obtained in step S107. Here, step S109 will be described in detail with reference to FIG.

At this time, when the frequency change is determined (S111), the user terminal 200 is requested to change the frequency of the second base station 103 through the RRC Connection Reconfiguration command (S113). Then, the user terminal 200 changes the uplink frequency to the frequency of the second base station 103 (S115).

4 is a flowchart illustrating an operation of a base station according to an embodiment of the present invention. Specifically, step S109 of FIG. 3 is shown in detail.

Referring to FIG. 4, the multicarrier controller 170 determines whether the received signal strength R 1 measured by the measuring unit 130 is equal to or greater than a specific threshold (S 201).

At this time, if it is less than the specific threshold, step S101 of FIG. 3 is started again.

However, if it is above a certain threshold value, it can be judged that the interference of the adjacent base station is large or the unnecessary wave of the adjacent band is a severe frequency.

Accordingly, the multicarrier controller 170 determines whether the difference value between the received signal strength R1 and the received signal strength R2 of the adjacent base station, that is, the second base station 103 is equal to or greater than a predefined hysteresis parameter (S203). Here, the hysteresis is one of the basic elements of the handover parameter that triggers the handover.

At this time, if it is less than the hysteresis parameter, step S101 of FIG. 3 is started again.

However, if the hysteresis parameter is abnormal, it is determined whether the frequency change condition is satisfied (S205). At this time, the frequency change condition can be set to take into account the uplink load and speed of the target frequency. In addition, it may include a load distribution condition for minimizing the existing inter-cell interference.

At this time, if the frequency change condition is not satisfied, the step S101 of FIG. 3 starts again.

However, when the frequency change condition is satisfied, it is determined to change to the target frequency, that is, the frequency of the second base station 103 (S207).

In this way, when the RSSI (R1) of its own frequency does not allocate data on the uplink, the multicarrier control unit 170 sets the RSSI (R2) of the target frequency, that is, (R2) is lower than R1, a frequency shift trigger or a handover trigger (RRC Connection Reconfiguration) trigger is determined in R2.

The embodiments of the present invention described above are not implemented only by the apparatus and method, but may be implemented through a program for realizing the function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (11)

A method for a base station to control multicarrier communication,
Obtaining unnecessary wave and cell interference information of an adjacent base station through an inter-base station interface, and
Determining a frequency shift based on the spurious wave and the cell interference information
Wherein the multicarrier communication control method comprises: The method according to claim 1,
The spurious and cell interference information may include at least one of:
The uplink received signal strength is included,
Before the exchanging step,
Further comprising the step of the base station measuring an uplink received signal strength,
Wherein the determining comprises:
And determines a frequency shift for multicarrier communication based on the measured received signal strength of the uplink and the received signal strength of the uplink of the neighbor base station. 3. The method of claim 2,
Wherein the measuring step comprises:
Measuring a received signal strength in an uplink subframe in which resources are not allocated,
Wherein the uplink received signal strength of the neighbor base station is determined by:
And the received signal strength is measured in an uplink sub-frame to which the resource is not allocated. 3. The method of claim 2,
Wherein the acquiring comprises:
Transmitting a load measurement request message to the neighbor base station, and
Receiving a load measurement response message to which the spurious and cell interference information is added from the neighbor base station
Wherein the multicarrier communication control method comprises: 3. The method of claim 2,
Wherein the determining comprises:
And determines to move to a frequency of the neighbor base station if the received signal strength of the uplink of the neighbor base station is lower than the measured received signal strength of the uplink. 6. The method of claim 5,
Wherein the determining comprises:
Determining whether the measured uplink received signal strength is greater than or equal to a predefined threshold;
Determining whether the difference value between the uplink received signal strength of the neighbor base station and the measured uplink received signal strength is greater than or equal to a predefined hysteresis parameter,
Determining a shift to a frequency of the neighbor base station if the hysteresis parameter is equal to or greater than the predefined hysteresis parameter
Wherein the multicarrier communication control method comprises: A measurement unit for measuring spurious waves and cell interference information of a first frequency used by the measurement unit,
A base station communication unit for obtaining spurious waves and cell interference information of a second frequency used by an adjacent base station through an inter-base station interface, and
A multi-carrier control unit for determining movement between the first frequency and the second frequency based on the spurious wave and the cell interference information,
/ RTI > 8. The method of claim 7,
Wherein the measuring unit comprises:
Measuring an uplink received signal strength of the first frequency,
The base station communication unit includes:
Acquires an uplink received signal strength of the second frequency,
Wherein the multi-
When the strength of the uplink received signal strength of the first frequency to which the user terminal is connected is higher than the strength of the uplink received signal strength of the second frequency, the user terminal is connected to the user terminal at the second frequency through radio resource connection re- Requesting base station. 9. The method of claim 8,
Wherein the measuring unit comprises:
Measuring an uplink received signal strength of the first frequency in an uplink subframe in which resources are not allocated,
The base station communication unit includes:
And acquires an uplink received signal strength of the second frequency measured in an uplink subframe in which the resource is not allocated. 9. The method of claim 8,
The base station communication unit includes:
And transmits a load measurement request message to the neighbor base station to receive a load measurement response message to which an uplink received signal strength of the second frequency is added. 11. The method of claim 10,
Wherein the multi-
Wherein the received signal strength of the uplink of the first frequency is greater than or equal to a predefined threshold and the difference between the received signal strength of the uplink of the neighbor base station and the received signal strength of the measured uplink is greater than or equal to a predefined hysteresis parameter , Determines to change the frequency to which the user terminal is connected to the second frequency.

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