KR20130107158A - Apparatus and method for transmitting inter-heterogeneous cell interference coordination information - Google Patents

Abstract

PURPOSE: A device for transmitting interference control information among heterogeneous cells and a method thereof are provided to control signal interference among heterogeneous cells by using an inter-cell interference control method based on time division multiplexing (TDM). CONSTITUTION: A reception part (1565) receives an almost blank sub-frame (ABS) pattern, which applies an ABS with reduced transmission power in order to prevent an eNodeB (eNB) from being interfered by a sub-frame where signal transmission of a heterogeneous eNB is scheduled, from the heterogeneous eNB based on TDM. A measurement restriction pattern construction part (1570) constructs a measurement restriction pattern, which restricts sub-frames measured by a terminal, based on the ABS pattern. A transmission part (1575) transmits the ABS pattern and the measurement restriction pattern to the terminal. [Reference numerals] (1505,1565) Reception part; (1510) Measurement operation part; (1515,1540,1575) Transmission part; (1535) ABS pattern construction part; (1570) Measurement restriction pattern construction part; (AA) ABS pattern, power offset; (BB) Measurement restriction pattern, ABS pattern, downlink traffic; (CC) ABS pattern; (DD) Measurement result

Description

Apparatus and method for transmitting interference coordination information between heterogeneous cells {APPARATUS AND METHOD FOR TRANSMITTING INTER-HETEROGENEOUS CELL INTERFERENCE COORDINATION INFORMATION}

The present invention relates to wireless communication, and more particularly, to an apparatus and method for transmitting inter-cell interference coordination information.

As wireless communication technology develops, a heterogeneous network environment is emerging.

The heterogeneous network environment includes a macro cell, a femto cell, a pico cell, and the like. The femto cell and pico cell are systems that cover an area smaller than the radius of the existing mobile communication service as compared to the macro cell.

In such a communication system, a user terminal present in any one of a macrocell, a femtocell, and a picocell may cause inter-cell interference in which signal interference is caused by a signal generated from another cell.

In this case, there is a need for a method and apparatus for receiving a downlink transmission in a region where a terminal has minimal or no inter-cell interference.

The present invention provides an apparatus and method for transmitting interference coordination information between heterogeneous cells.

Another technical problem of the present invention is to provide an apparatus and method for adjusting interference of heterogeneous inter-cell signals using a TDM-based inter-cell interference coordination scheme.

Another technical problem of the present invention is to provide an apparatus and method for providing frame pattern information for coordinating interference between heterogeneous signals.

According to an aspect of the present invention, a method for coordinating inter-cell interference by a base station in a heterogeneous network system includes transmitting power such that a subframe scheduled for transmission of a signal of a heterogeneous base station does not cause interference to the base station based on time division multiplexing. Receiving an ABS pattern, which is a pattern to which an Almost Blank Subframe (ABS) is applied, from the heterogeneous base station; Configuring a measurement limit pattern based on the ABS pattern, the measurement limit pattern being a pattern in which a subframe in which measurement is performed by a terminal is restricted; And transmitting the ABS pattern and the measurement restriction pattern to the terminal.

According to another aspect of the present invention, a base station for coordinating cell-to-cell interference in a heterogeneous network system includes a subframe in which transmission power is attenuated so that a subframe scheduled for signal transmission of the heterogeneous base station does not cause interference to the base station based on time division multiplexing. Receiving unit for receiving from the heterogeneous base station ABS pattern that is applied to the pattern; A measurement restriction pattern configuration unit configured to configure a measurement restriction pattern, which is a pattern in which a subframe in which measurement is performed by a terminal, is restricted based on the ABS pattern; And a transmitter for transmitting the ABS pattern and the measurement restriction pattern to the terminal.

According to another aspect of the present invention, a method for coordinating inter-cell interference by a terminal in a heterogeneous network system includes a sub-transmitted power having attenuated transmit power such that a subframe scheduled for signal transmission of the heterogeneous base station does not interfere with the base station based on time division multiplexing. Receiving from the base station or the heterogeneous base station an ABS pattern which is a pattern to which a frame (ABS) is applied and a measurement restriction pattern which is a pattern in which a subframe in which measurement is performed is restricted; Performing a measurement based on the measurement restriction pattern; And receiving downlink traffic from the heterogeneous base station based on a result of the measurement with the transmission power allocated by the heterogeneous base station based on the ABS pattern.

According to another aspect of the present invention, a terminal for coordinating inter-cell interference in a heterogeneous network system includes a subframe in which transmission power is attenuated so that a subframe scheduled for signal transmission of a heterogeneous base station does not cause interference to the base station based on time division multiplexing. A receiving unit for receiving from the base station or the heterogeneous base station an ABS pattern which is a pattern to which ABS) is applied and a measurement restriction pattern which is a pattern in which a subframe in which measurement is performed is restricted; And a measurement performing unit performing a measurement based on the measurement limit pattern, wherein the receiving unit is downward from the heterogeneous base station based on a result of the measurement with transmission power allocated by the heterogeneous base station based on the ABS pattern. Receive link traffic.

According to the present invention, downlink traffic may be transmitted by allocating transmission power even in a subframe corresponding to the ABS.

According to the present invention, by using an ABS capable of performing downlink transmission with limited power, it is more effective in terms of system efficiency than ABS that does not transmit a signal at all.

According to the present invention, a measurement limit pattern for transmitting ABS pattern information as well as a measurement limit pattern for RRM / RLM measurement or CSI measurement can be configured and transmitted, and the measurement result of the terminal based on the measurement limit pattern and the ABS pattern It can increase the reliability of.

1 is a diagram schematically illustrating a concept of a heterogeneous network including a macro base station, a femto base station, and a pico base station according to the present invention.
2 is a diagram schematically illustrating that a terminal is affected by interference between a macro cell, a femto cell, and a pico cell in downlink.
3 is a flowchart illustrating an operation of transmitting frame pattern information for inter-cell interference coordination in a heterogeneous network system according to the present invention.
4 is a diagram illustrating ABS performing downlink transmission with limited power according to the present invention.
5 and 6 are diagrams showing an example of the configuration of the measurement limit pattern according to the present invention.
7 shows another example of the measurement restriction pattern configuration according to the present invention.
8 shows another example of the measurement restriction pattern configuration according to the present invention.
9 is a view illustrating a power offset value of the ABS according to the present invention.
10 shows an example of a method of transmitting ABS pattern information according to the present invention.
11 shows another example of a method of transmitting ABS pattern information according to the present invention.
12 is a flowchart illustrating an operation of a base station transmitting frame pattern information for inter-cell interference coordination in a heterogeneous network system according to the present invention.
13 is a flowchart illustrating an operation of a terminal receiving frame pattern information for inter-cell interference coordination in a heterogeneous network system according to the present invention.
14 is a flowchart illustrating an operation of a base station transmitting frame pattern information for inter-cell interference coordination in a heterogeneous network system according to the present invention.
15 is a block diagram illustrating an apparatus for transmitting and receiving frame pattern information according to the present invention.

Hereinafter, the contents related to the present invention will be described in detail with reference to exemplary drawings and embodiments, together with the contents of the present invention. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In addition, in describing the embodiments of the present specification, when it is determined that the detailed description of the related well-known configuration or function may obscure the subject matter of the present specification, the detailed description thereof will be omitted.

In addition, the present invention will be described with respect to a wireless communication network. The work performed in the wireless communication network may be performed in a process of controlling a network and transmitting data by a system (e.g., a base station) Work can be done at a terminal connected to the network.

Simple cell division of macro and micro cells is difficult to meet the growing demand for data services. Therefore, data services for indoor and outdoor small areas can be operated using pico cells, femto cells, and wireless relays. Although the use of small cells is not particularly limited, pico cells can generally be used in communication shadow areas that are not covered by macro cells alone, or in areas with high data service requirements, so-called hot zones. A femto eNB is generally used in an indoor office or home. In addition, the wireless relay can compensate for the coverage of the macrocell. By configuring a heterogeneous network, not only the shadow area of the data service can be eliminated, but also the data transmission speed can be increased.

1 is a diagram schematically illustrating a concept of a heterogeneous network including a macro base station, a femto base station, and a pico base station according to the present invention. Although FIG. 1 illustrates a heterogeneous network composed of a macro base station, a femto base station, and a pico base station for convenience of description, the heterogeneous network may include a relay or another type of base station.

Referring to FIG. 1, a macro base station 110, a femto base station 120, and a pico base station 130 are operated together in a heterogeneous network. The macro base station 110, the femto base station 120, and the pico base station 130 provide their own cell coverage of the macro cell, femto cell, and pico cell to the terminal, respectively.

The femto base station 120 is a low power wireless access point, for example, a base station for a small mobile communication used in a room such as a home or an office. The femto base station 120 can access the mobile communication core network using a home or office DSL or cable broadband. The femto base station 120 may support a self-organization function. Self-organization functions are classified into self-configuration, self-optimization, and self-monitoring.

The femtocell can distinguish registered users from unregistered users and allow access only to registered users. (CSG), and the open user group (hereinafter referred to as "OSG ") is a group that allows access to only a registered user, and a cell that allows access only to registered users is called a closed group . It is also possible to operate these two methods in combination.

The femto base station 120 is called a Home NodeB (HNB) or Home eNodeB (HeNB) in 3GPP. The femto base station 120 aims to provide specialized services only to members belonging to the CSG. In terms of providing a service, when the femto base station 120 provides a service only to the CSG group, the cell provided by the femto base station 120 is referred to as a CSG cell.

Each CSG has a unique identifier, which is referred to as a CSG identity. A terminal can have a list of CSGs belonging to itself as a member. Such a CSG list is also called a whitelist. It is possible to confirm which CSG the CSG cell supports by reading the CSG ID included in the system information. The terminal that has read the CSG ID is regarded as a cell that can access the cell only when it is a member of the corresponding CSG cell, that is, when the CSG corresponding to the CSG ID is included in its own CSG whitelist.

The femto base station 120 does not always need to allow access to the CSG terminal. In addition, depending on the configuration of the femto base station 120, it is possible to allow the connection of the terminal other than the CSG member. Which terminal is allowed to access is changed according to the configuration setting of the femto base station 120, where the configuration setting means the setting of the operation mode of the femto base station 120. The operation mode of the femto base station 120 is classified into three types according to which UE provides a service.

1) Closed access mode: A mode that provides services only to specific CSG members. The femto base station 120 provides a CSG cell.

2) Open access mode: A mode that provides services without restriction of a specific CSG member, like a normal BS. The femto base station 120 provides a general cell that is not a CSG cell.

3) Hybrid access mode: A mode in which a CSG service can be provided to a specific CSG member and a service is provided to a non-CSG member in the same manner as a general cell. The CSG member UE is recognized as a CSG cell, and the non-CSG member UE is recognized as a general cell. Such a cell is called a hybrid cell.

In a heterogeneous network in which a femtocell is operated together with a macro cell, when a femtocell is in an open access mode, a user can access a desired cell among a macro cell and a femtocell to use a data service.

When the femto cell is in, for example, a closed mode, the end user using the macro cell will not be able to use the femto cell even if the macro cell is interfering with the femto cell transmitting a strong signal.

The macro base stations or between the macro base station and the pico base station are connected to each other via an X2 interface. The X2 interface maintains the operation of seamless and lossless handover between base stations and supports management of radio resources. Therefore, the X2 interface plays a large role in inter-cell interference coordination (ICIC) between macro base stations.

2 is a diagram schematically illustrating that a terminal is affected by interference between a macro cell, a femto cell, and a pico cell in downlink.

Referring to FIG. 2, the terminal 250 may access a femto base station 230 and use a femto cell. However, if the femto base station 230 is in the CSG mode, and the terminal 260 near the femto base station 230 is not a registered user terminal of the CSG, the terminal 260 cannot access a femto cell with strong signal strength. There is no choice but to access the macro base station 210 having a relatively weak signal strength compared to the signal strength of the femto cell. Therefore, in this case, the terminal 260 may receive an interference signal from the femto cell.

In addition, the terminal 240 may access the pico base station 220 to use the pico cell. However, at this time, the terminal 240 may receive interference by the signal of the macro base station 210.

As such, inter-cell interference is a macro cell or a pico cell that is more affected by the interference or has to be protected from the interference. On the other hand, an aggressor cell that affects or is less affected by the Victim cell by the interference is a femto cell.

Inter-Cell Interfernce Coordination (ICIC) is a method of reducing inter-cell interference. In general, inter-cell interference coordination is a method for supporting reliable communication to a user when a user belonging to a big team cell is near an aggregator cell. In order to coordinate inter-cell interference, for example, a scheduler may be imposed on the use of certain time and / or frequency resources. It may also impose a constraint on the scheduler how much power to use for a particular time and / or frequency resource.

3 is a flowchart illustrating an operation of transmitting frame pattern information for inter-cell interference coordination in a heterogeneous network system according to the present invention.

For example, the first base station may be a macro base station, the second base station may be a pico base station, and may transmit a frame pattern to the terminal for coordination of inter-cell interference between the macro cell of the macro base station and the pico cell of the pico base station.

As another example, the operation between the first base station and the second base station may be applied between the femto base station and the macro base station, and may be equally applied between the macro base station and the micro base station, and between the femto base station and the pico base station.

Referring to FIG. 3, the first base station configures an ABS (Almost Blank Subframe) pattern for interference coordination between different types of cells (eg, macro cell and pico cell) (S300). The first base station configures the ABS pattern to minimize or not give interference to the second base station.

Here, ABS refers to a subframe in which transmission power is attenuated (or no signal is transmitted) in order to minimize interference, and ABS pattern refers to a pattern in which ABS is applied in a radio frame for coordination of interference and has a specific period. As a pattern, for example, the ABS pattern may be configured in units of 40 ms.

ABS is a time division multiplexing (TDM) based inter-cell interference coordination scheme in which heterogeneous cells share time resources such as subframes. The interference can be adjusted by variably configuring the frame pattern structure itself within any periodic interval composed of multiple subframes.

As an example of the ABS according to the present invention, the ABS may transmit control information such as a physical downlink control channel (PDCCH) with limited power (or attenuated power), and control information necessary for the terminal for backwards compatibility And a subframe capable of transmitting data information, signaling, and system information. As such, subframes capable of downlink transmission with some limited power include non-zero ABS, non-zero power ABS, and non-zero based ABS. based ABS) or low power ABS, but may be expressed in various ways, hereinafter, such a subframe is called ABS.

As another example of ABS according to the present invention, ABS is defined as a subframe that transmits no transmission power such as control information, data information, signaling (signals transmitted for channel measurement and synchronization, etc.) transmitted through the subframe. You may.

 4 is a diagram illustrating ABS performing downlink transmission with limited power according to the present invention.

Referring to FIG. 4, ABS1 405 and ABS2 410, which are ABS performing downlink transmission with limited power, are transmitted with reduced transmit power P ₁ 455. At this time, since P ₁ 455 is a transmission power smaller than the transmission power P ₀ 450 of the normal subframe 415 which is a subframe other than ABS, but is not ₀ , the base station determines ABS1 405 and ABS 410. PDSCH (Physical Downlink Shared Channel) can be allocated and used. In addition, PDCCH, Physical Hybrid ARQ Indicator Channel (PHICH), Physical Control Format Indicator Channel (PCFICH), Demodulation Reference Signal (DM-RS), or Channel Status Information-Reference Signal (CSI-RS) are also referred to as P ₁ (455). Low power can be transmitted.

Such power reduction is set to semi-static, and all ABS 455 and 410 may be set to have the same power reduction level. Or, it may be set to dynamic as needed. In addition, in the ABS 405 and 410, a cell specific reference signal (CRS) is transmitted to the power P ₀ 450 as in the normal subframe 415. In addition, a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a physical broadcast channel (PBCH), a system information block 1 (SIB1), a paging, or a positioning reference signal (PRS) are also transmitted without power attenuation.

If the base station is unable to perform downlink scheduling or downlink transmission at the timing (or subframe) of the ABS location, it may affect system performance in part. ABS is more advantageous in terms of system efficiency than ABS, which transmits no signal at all.

Referring back to FIG. 3, according to the ABS pattern configured by the first base station in step S300, the first base station can transmit traffic in the normal subframe but uses limited transmit power in the ABS (or no traffic at all). Set the position or timing of the normal subframe and the ABS, respectively.

Following step S300, the first base station transmits the configured ABS pattern to the second base station (S305). For example, the macro base station may transmit the above-described ABS pattern to the pico base station through the X2 interface.

The second base station configures a measurement restriction pattern (measurement restriction pattern, or "measurement pattern") for the measurement to be performed by the terminal based on the received ABS pattern (S310).

Here, the measurement limit pattern refers to pattern information on the position and timing of the measurable subframe designated by the base station for the measurement of the terminal. A location where the interference can be minimized by transmitting a measurement restriction pattern that can avoid a situation in which the measurement result may be severely affected by the interference from the first base station (for example, the macro base station or the femto base station). Alternatively, the terminal may proceed with the measurement at the timing. This can increase the reliability of the measurement results of the terminal.

The measurement restriction pattern includes a measurement restriction pattern for RRM (Radio Resource Management) / RLM (Radio Link Monitoring) measurement and a measurement restriction pattern for CSI (Channel State Information) measurement.

1) Measurement limit pattern for RRM / RLM measurements.

The measurement limit pattern for the RRM / RLM measurement must be configured in consideration of the ABS pattern. That is, the second base station configures the RRM / RLM measurement restriction pattern in consideration of the ABS pattern of the first base station.

In this case, the RRM is a radio resource so that the UE monitors the network connection state to provide measurement, cell search, cell research, or handover in order to provide mobility and the like. Says to manage it. RLM refers to the management of the connection state that the UE monitors the synchronization or out-of-sync state with the cell and reports to the upper layer.

2) Measurement limit pattern for CSI measurement.

Unlike the measurement restriction pattern for RRM / RLM measurement, the measurement restriction pattern for CSI measurement is not limited to the ABS pattern so that channel state (channel state or channel status) can be evaluated at various positions as necessary. In addition, two subframe sets are defined in the measurement restriction pattern for CSI measurement and may be transmitted to the terminal.

Here, the CSI measurement refers to a measurement for the UE to determine the channel state in the current cell and report it to the base station, and can check the channel state through a cell specific reference signal (CRS). In addition, the CSI measurement refers to a measurement for reporting information about a channel quality indicator (CQI), a precoding matrix index (PMI), and a rank indicator (RI). Here, the CQI refers to an indicator that the terminal checks the channel state, determines a possible modulation and coding rate, and transmits the same to the base station, and the base station modulates and codes the downlink through a value reported in the form of a CQI. The rate can be determined. PMI is an index for determining antenna mapping for a layer (stream of individual data). The UE checks a downlink channel quality for each antenna and then checks a precoding matrix. A matrix is set up and a related index, PMI, is reported to the base station. The RI designates the number of layers and is an indicator for streams of different signals in downlink.

5 and 6 are diagrams showing an example of the configuration of the measurement limit pattern according to the present invention. As an example, the measurement restriction pattern between the macro base station and the pico base station and the measurement restriction pattern between the macro base station and the femto base station will be described.

Referring to FIG. 5, when the macro base station 505 interferes with the pico base station 500, the pico base station 500 may configure a measurement limit pattern based on the ABS pattern of the macro base station 505. At this time, the measurement limit pattern is not necessarily the same as the ABS pattern. Since the subframe # 3 550 and the subframe # 6 555 of the macro base station 505 are ABS, the UE measures the measurement 520 for the serving cell or the neighbor cell in the pico base station. 6 can be performed. Alternatively, the operation may be performed simultaneously in subframe # 3 and subframe # 6. In addition, the measurement subframe (s) for the serving cell and the measurement subframe (s) for the neighbor cell may not be the same.

In addition, when the femto base station 510 interferes with the macro base station 505, the macro base station 505 is the ABS (560, 565, 570) of the femto base station 510 and the ABS (550, The measurement limit pattern may be configured so that the 555 does not overlap. Since the subframes # 2 560, subframes # 5 565, and subframes # 8 570 of the femto base station are ABS, the UE measures the serving cell or neighbor cell 525 in the macro base station by subframe #. 2, subframe # 5 or subframe # 8. Alternatively, the operation may be performed simultaneously in subframe # 2, subframe # 5, and subframe # 6. In addition, the measurement subframe (s) for the serving cell and the measurement subframe (s) for the neighbor cell may not be the same.

Referring to FIG. 6, even in a subframe corresponding to the ABS of the macro base station 600, the terminal may perform measurement 620 of a serving cell or a neighbor cell in the macro base station. That is, the UE not only subframe # 2, subframe # 5, or subframe # 8 corresponding to the ABS 660, 670, 680 of the femto base station 605, but also the subframe # 3 corresponding to the ABS of the macro base station 600 (650). Or subframe # 6 655 may perform measurement 620 for the serving cell or neighbor cell in the macro base station. In addition, the measurement subframe (s) for the serving cell and the measurement subframe (s) for the neighbor cell may not be the same.

7 shows another example of the measurement restriction pattern configuration according to the present invention. The configuration of the measurement limit pattern for CSI measurement, and the measurement limit pattern for CSI measurement is defined by two subframe sets (first measurement limit pattern 710, second measurement limit pattern 715). If only one measurement restriction pattern for CSI measurement is considered, it is difficult to obtain accurate CSI information due to circumstances such as additional interference in the surroundings (for example, influence from another macro base station other than the macro base station). have. Therefore, an additional measurement restriction pattern is constructed to further improve the accuracy of the CSI measurement. The measurement restriction pattern for the CSI measurement may be configured in various ways due to the influence on interference from neighboring base station (s), the need for CQI reporting for the full band or subband, and the like.

Referring to FIG. 7, an ABS pattern 720 or a measurement limit pattern 725 is configured in units of two radio frames 700.

First, in the DL transmission 705 of the macro base station, the ABS pattern may be configured as “0111010001 0101011101” and represented as a bitmap, and “1” denotes a subframe position using the ABS 720. On the contrary, the ABS pattern may be configured as “10001011101 010100010”, and “0” may mean a subframe position using the ABS 720.

Subsequently, the first measurement restriction pattern 710 of the measurement restriction pattern for CSI measurement may be configured as “0101001001 0001000100” and represented as a bitmap, and “1” indicates a subframe 725 in which CSI measurement may be performed. ). On the contrary, the first measurement restriction pattern 710 may be configured as “1010110110 1110111011”, and “0” may mean a subframe 725 in which CSI measurement may be performed.

Also, the second measurement limit pattern 715 may be configured as “0010010000 0100001001” and represented as a bitmap, and “1” means a subframe 725 in which CSI measurement may be performed. On the contrary, it may be configured as “1101101111 1011110110” and “0” may mean a subframe 725 in which CSI measurement may be performed.

The base station may be configured based on the ABS pattern received from the macro base station measurement limit pattern, but may be configured based on the ABS pattern of the macro base station, but is not necessarily limited to the ABS pattern. The subframe # 6 750 of the first radio frame of the first measurement limit pattern 710 of FIG. 7 does not correspond to the ABS pattern but constitutes a measurement limit pattern.

8 shows another example of the measurement restriction pattern configuration according to the present invention. It is a figure explaining the timing in case ABS and measurement restriction pattern exist in a base station. The first base station and the second base station may each be a macro base station, a pico base station, or a femto base station.

Referring to FIG. 8, in the first base station 800, subframe # 2 and subframe # 5 of radio frame 1 are ABS 850, and subframe # 0, subframe # 3, and subframe # of radio frame 2. 8 degrees ABS 850.

Further, in the second base station 805, subframes # 1, subframe # 4, and subframe # 7 of radio frame 1 are ABS 855, and subframes # 1, subframe # 4, and subframe of radio frame 2. # 7 is ABS 855.

If the first base station 800 can know about the ABS pattern 855 of the second base station, the first base station 800 considers the ABS pattern 855 of the second base station to determine the measurement limit pattern 860. Configure. As a result, the first base station 800 subframe # 1 and subframe # 4 of the radio frame 1 corresponding to a part of the ABS pattern 855 of the second base station, subframe # 1 and subframe # of the radio frame 2 4 is configured as the measurement limit pattern 860.

Based on the measurement restriction pattern 860, the terminal may perform a measurement 865 for a serving cell or neighbor cell in the first base station.

Referring back to FIG. 3, following step S310, the second base station transmits the measurement limit pattern configured through RRC dedicated signaling to the terminal, and the first base station transmits the ABS pattern and the power offset value Δ of the ABS. _ABS ) is transmitted to the UE through the system information 350 or the RRC dedicated signaling 355 (S315). The transmission of the measurement limit pattern and the transmission of the ABS pattern (and the ABS power offset value) may be performed simultaneously, the transmission of the measurement limit pattern may be performed first, and the transmission of the ABS pattern (and the ABS power offset value) may be performed first. May be For example, when the terminal in the macro cell area receives the ABS pattern and the power offset value of the macro base station, the terminal may decode or demodulate using the power offset at a position corresponding to the ABS.

As another example, in a situation where the UE is located in the pico cell region and receives downlink from the pico cell, when the interference from the macro base station is severe outside the pico cell region (for example, the CRE extended region), the pico cell is determined from the macro base station. ABS pattern information can be checked and used. In this case, the ABS pattern information and the macro may include the ABS power offset value used for the ABS. In consideration of the ABS pattern information and the ABS power offset value, a pico base station corresponding to a pico cell may perform downlink scheduling to a terminal located in a pico cell in a corresponding subframe in consideration of ABS pattern information to a terminal located in the pico cell. Can be. In this case, the macro may be used to determine the amount or power value of the downlink resource to be allocated to the corresponding subframe in consideration of the ABS power offset value used for the ABS. In other words, the picocell can know about the amount of power used by the macro base station through the ABS offset value used for the ABS in the macro. Through this, the pico base station can more accurately grasp the amount of power to be allocated to the location corresponding to the ABS pattern of the macro base station of the pico cell or the downlink resource to be scheduled. The pico base station may perform downlink scheduling using the ABS pattern or the ABS power offset value. At this time, the pico base station may transmit the ABS power offset, or attenuated power value of the macro base station to the terminal. The terminal located in the pico cell may receive the ABS power offset or attenuated power value of the macro base station and decode or demodulate the content allocated to the downlink allocated by the pico base station.

On the other hand, from the viewpoint of the macro terminal located in the macro base station, a subframe allocated and used for downlink data transmission in the macro base station may be classified into two types.

First, normal subframe, second, ABS subframe.

In FIG. 9, a normal subframe is a general subframe, and the amount or size of power used corresponds to P _{PDSCH - normal} 956. The ABS subframe is a special subframe that defines a specific subframe in the form of TDM so that the power transmission is completely limited or only a part of the subframe unlike the general subframe. The amount of power allocated to the subframe of the _ABS corresponds to P _{PDSCH _ ABS} 957.

In order to receive downlink data scheduled by the macro base station from the terminal located in the macro base station, the macro base station should know that the downlink data can be scheduled through different power amounts through two different types of subframes. do.

In other words, the macro base station should inform the macro terminal of the location, timing, and amount of transmission power corresponding to the normal subframe. In addition, the macro base station should inform the macro terminal of the position or pattern information or timing information corresponding to the ABS subframe and the amount of transmission power. In this case, when the position corresponding to the ABS subframe is determined, since the rest corresponds to the normal subframe, it is not necessary to separately inform the position of the normal subframe.

When the UE transmits downlink scheduled data through an ABS subframe in addition to the normal subframe, the UE may decode or demodulate the downlink data by using information about an accurate position or timing and an allocated power amount.

If the amount of power allocated to the ABS or the amount of data (PDSCH, etc.) can be adjusted dynamically, information on the ABS subframe may be transmitted using PDCCH or MAC CE (Control Element) in addition to the ABS pattern.

The measurement restriction pattern may be included in RRC signaling and transmitted to the terminal as shown in Table 1 below.

-ASN1START RadioResourceConfigDedicated :: = SEQUENCE { [[AbsPatternPCell-r10 MeasSubframePatternPCell-r10 OPTIONAL-Need ON [[measSubframePatternPCell-r10 MeasSubframePatternPCell-r10 OPTIONAL-Need ON ]] } MeasSubframePatternPCell-r10 :: = CHOICE { release NULL, setup MeasSubframePattern-r10 }

RadioResourceConfigDedicated is RRC dedicated signaling, and MeasSubframePatternPCell-r10 is a measurement restriction pattern for the main serving cell.

9 is a view for explaining the power offset value Δ _ABS of the ABS according to the present invention.

Referring to FIG. 9, the ABS according to the present invention is a subframe capable of downlink transmission with some limited power, and since the transmission power is attenuated but not 0, the ABS power offset in relation to the power allocation of the UE. ABS pattern information for applying an offset value and the ABS power offset value is required. Alternatively, power value information allocated to the ABS may be requested instead of the ABS power offset value.

Power allocation in the normal subframes 900, 910 and ABS 905, 915 is represented using P _CRS 950, P _PDSCH 955, Δ _normal (960, 970) and Δ _ABS (965, 975). Here, P _CRS means transmission power for CRS transmission. P _PDSCH means transmission power for PDSCH transmission, and P _PDSCH includes transmission power for PDSCH transmission in a normal subframe (P _{PDSCH _ normal} , 956) and transmission power for PDSCH transmission in _ABS (P _{PDSCH _ ABS} , 957). Δ _{n orm al} (960,970) is the difference between P _CRS 950 and P _{PDSCH _ normal} (956), and Δ _ABS (965,975) is the difference between P _CRS 950 and P _{PDSCH _ ABS} (957). Means.

In case of a UE corresponding to a transmission mode 1 to 6, the CRS is determined as a phase reference to demodulate the PDSCH and demodulated. In addition, the terminal corresponding to the transmission mode 7 demodulates through the DM-RS.

In this case, the power state between the CRS and the PDSCH can be known in the case of the normal subframe, but the power level (P _{PDSCH _ ABS} ) of the _ABS cannot be known and thus the PDSCH cannot be demodulated. That is, demodulation of the PDSCH in the subframe for the ABS is impossible unless accurate information related to the position and timing is provided for the ABS pattern of the base station.

As such, unlike normal subframes, in ABS, transmission power is allocated by using a unique power offset Δ _ABS , so that the UE transmits ABS power offset Δ _ABS information and ABS power offset Δ _{ABS for} downlink transmission. In order to apply, it is required to receive the ABS pattern information of the first base station in advance.

As such, the first base station informs the terminal of the ABS power offset value and the ABS pattern information. In addition, the first base station transmits the ABS pattern information to the second base station that is the neighboring base station so that the terminal can know the exact power offset value.

Here, the description of transmitting the PDSCH through the ABS is just an example, and PDCCH, PHICH, PCFICH, DM-RS, or CSI-RS may also be low power transmitted through the ABS.

A terminal receiving a service from the macro base station in the macro cell region (hereinafter referred to as a "macro terminal") may not know which subframe is ABS even if it receives the measurement restriction pattern without receiving the ABS pattern itself. Although the pattern information on the measurement limit pattern and the position or timing of the ABS is not necessarily the same, or the measurement limit pattern does not overlap with the ABS pattern at all, the measurement limit pattern may be performed even if necessary in the subframe corresponding to the pattern in the ABS. This is because it can be set. In particular, the measurement limit pattern for RRM / RLM measurement is configured in the ABS pattern interval of the base station affected by the interference, while the measurement limit pattern for CSI measurement needs to be considered in consideration of the influence of neighboring base stations and the like. Accordingly, the measurement restriction pattern can be configured flexibly.

Meanwhile, not only the first base station but also the second base station may transmit ABS pattern information of the first base station to the terminal. Since the first base station transmits the ABS pattern to the second base station, since the second base station knows the ABS pattern of the first base station, the second base station may also transmit the ABS pattern information of the first base station to the terminal.

The second base station may transmit traffic through scheduling in a subframe corresponding to the ABS pattern having minimal interference by using the ABS pattern information and the ABS power offset value, and allocate transmission power.

The UE may decode or demodulate the downlink traffic such as PDSCH using the ABS pattern and the power offset value.

Meanwhile, according to the present invention, the first base station may transmit the ABS pattern information and the power offset value of the ABS using the system information 350 or the RRC dedicated signaling 355. It is also possible for the second base station to transmit ABS pattern information of the first base station to the terminal using the system information 350 or the RRC dedicated signaling 355 (not shown).

1) ABS pattern information and power offset value transmission of ABS through system information 350

When the UE needs to know which subframe is ABS, when the UE needs to know the limitation information in a specific cell in advance, when the UE is in the idle mode, the base station informs the ABS pattern information to the UE.

The base station adds an ABS pattern to the system information 350 and transmits it to the terminal through a broadcast control channel (BCCH). At this time, the ABS pattern is static or semi-static.

The system information 350 may further include an ABS power offset value Δ _ABS as well as an ABS pattern. Alternatively, the system information 350 may include an ABS transmission power value itself.

The ABS pattern included in the system information 350 and transmitted may be 4 radio frame lengths (40 ms and 40 subframes). The ABS pattern may be configured in the form of a bitmap, and a portion corresponding to "0" may be ABS, or conversely, a portion corresponding to "1" may be ABS. The following table shows an example of the ABS pattern according to the present invention.

Wireless frame 1 Wireless frame 2 Wireless frame 3 Wireless frame 4 0010010010 0101010101 1001001001 1110001110

This is the case where the ABS pattern is configured so that the portion corresponding to "1" means ABS.

The terminal may selectively apply the ABS pattern as needed.

In addition, the UE may apply an ABS pattern as a subframe corresponding to “0” means ABS.

The following table shows an example of the system information 350 includes the ABS pattern and the ABS power offset value. The system information 350 is a system information block 2.

SystemInformationBlockType2 :: = SEQUENCE { AbsPatternInfo :: = sequence { AbsPowerOffset x; -x db AbsPattern CHOICE { AbsPatternFDD BIT STRING (SIZE 40), AbsPatternTDD CHOICE { AbsframeConfig1-5 BIT STRING (SIZE (20)), AbsframeConfig0 BIT STRING (SIZE (70)), AbsframeConfig6 BIT STRING (SIZE (60)), ... }, ... } } }

Here, "AbsPattern" is ABS pattern information and may be configured as a bitmap. "AbsPowerOffset" is an ABS power offset value and may be in dB.

2) ABS pattern information and ABS power offset value transmission through RRC dedicated signaling

The base station may transmit the ABS pattern to the terminal through the RRC dedicated signaling (355). In this case, the ABS pattern is not static, and may vary according to a certain part or situation, and may not be used in a special case. Therefore, the base station may transmit an ABS pattern at the time of radio resource configuration or measurement configuration as necessary.

ABS pattern information can be transmitted similarly to the method of setting the measurement limit pattern for RRM / RLM measurement and CSI measurement.

The RRC dedicated signaling 355 may further include ABS power offset value Δ _ABS . The RRC dedicated signaling 355 may include the ABS transmit power value itself.

Table 4 below relates to transmission of ABS pattern information related to radio resource configuration.

-ASN1START RadioResourceConfigDedicated :: = SEQUENCE { [[AbsPatternPCell-r10 MeasSubframePatternPCell-r10 OPTIONAL-Need ON [[measSubframePatternPCell-r10 MeasSubframePatternPCell-r10 OPTIONAL --NeedON]] AbsPatternInfo :: = sequence { AbsPowerOffset x; -x db AbsPattern CHOICE { AbsPatternFDD BIT STRING (SIZE 40), AbsPatternTDD CHOICE { AbsframeConfig1-5 BIT STRING (SIZE (20)), AbsframeConfig0 BIT STRING (SIZE (70)), AbsframeConfig6 BIT STRING (SIZE (60)), ... }, ... } } MeasSubframePatternPCell-r10 :: = CHOICE { release NULL, setup MeasSubframePattern-r10 } }

Here, "AbsPattern" is ABS pattern information and may be configured as a bitmap. "AbsPowerOffset" is an ABS power offset value and may be in dB. MeasSubframePattern-r10 and AbsPattern-r11 may be used together.

For example, when transmitting ABS pattern information (or ABS power offset value) using the RRC dedicated signaling 355, a measurement limit pattern for CSI measurement may be used.

10 shows an example of a method of transmitting ABS pattern information according to the present invention. Pattern information about ABS can be confirmed from measurement limit pattern information.

Referring to FIG. 10, the base station 1000 corresponds to subframe # 1, subframe # 4, subframe # 7, and subframe # 1, subframe # 4, and subframe # 7 of radio frame 2. It is set to perform downlink transmission with the ABS pattern 1015.

The base station 1000 may transmit information about a measurement allowance subframe (or a measurement limit subframe) to the terminal through the first measurement limit pattern 1005 and the second measurement limit pattern 1010. In this case, the measurement limit patterns 1005 and 1010 may be measurement limit patterns for CSI measurement or measurement limit patterns for RRM / RLM measurement.

In particular, the first measurement limit pattern 1005 may be set to be the same as the ABS pattern 1015 of the base station. In this case, when the terminal receives the information on the first measurement restriction pattern 1005, the terminal 1015 may also check the information about the ABS pattern 1015. As such, when it is determined that the ABS pattern 1015 and the first measurement restriction pattern 1005 always coincide with each other, the terminal may determine to match the ABS pattern unconditionally when receiving the measurement restriction pattern and process the ABS pattern.

If it is determined that the first measurement restriction pattern does not always coincide with the ABS pattern, then an indicator (or flag) indicating whether the first measurement restriction pattern is the same as or different from the ABS pattern is RRC-only signaling or the first. It may be included in the measurement restriction pattern information and transmitted to the terminal. This indicator is called a "pattern identification indicator". For example, when the pattern equality indicator is 1, it indicates that the measurement restriction pattern transmitted by the base station is identical to the ABS pattern of the base station. When the pattern equality indicator is 0, the measurement restriction pattern and the base station transmitted by the base station are indicated. ABS pattern is not the same. The pattern equality indicator may be transmitted or indicated together when informing of the measurement restriction pattern, or may be transmitted or indicated independently of the measurement restriction pattern.

As another example, the second measurement limit pattern may be set equal to the ABS pattern of the base station. In addition, an indicator indicating whether the second measurement limit pattern information is the same as the ABS pattern information may be further transmitted to the terminal.

Table 5 below shows the transmission of ABS pattern information (or ABS power offset value) using a measurement limit pattern for CSI measurement.

csi-SubframePatternConfig-r10 CHOICE { release NULL, setup SEQUENCE { AbsFlag-r11 ENUMERATED {setup} OPTIONAL-- Cond csi-MeasSubframeSet1-r10 MeasSubframePattern-r10, csi-MeasSubframeSet2-r10 MeasSubframePattern-r10 } }

Here, csi-SubframePatternConfig-r10 is a measurement limit pattern for CSI measurement, AbsFlag is a pattern equality indicator, csi-MeasSubframeSet1-r10 is a first measurement limit pattern, and csi-MeasSubframeSet2-r10 is a second measurement limit pattern. .

 As another example according to the present invention, when transmitting ABS pattern information (or ABS power offset value) using the RRC dedicated signaling 355, a new measurement restriction pattern may be used.

11 shows another example of a method of transmitting ABS pattern information according to the present invention. The case where ABS pattern information is transmitted using a new measurement restriction pattern.

Referring to FIG. 11, when the first measurement limit pattern 1110 and the second measurement limit pattern 1115 do not coincide with the ABS pattern 1120 of the base station, the base station 1100 may determine a new measurement limit pattern for ABS. The ABS measurement restriction pattern information 1120 is transmitted to the terminal using the measurement restriction pattern 1105.

If transmission of two measurement restriction patterns is required, such as in the case of measurement restriction pattern for CSI measurement, and the existing measurement restriction patterns 1110 and 1115 cannot be used to inform the ABS pattern, a new measurement restriction pattern ( 1105) is further configured and transmitted to the terminal.

For example, the measurement limit pattern 1105 for the ABS may be a measurement limit pattern for CSI measurement or a measurement limit pattern for RRM / RLM measurement. Or, it may be a new type of measurement restriction pattern for ABS.

By configuring the measurement restriction pattern 1105 for the ABS in addition to the existing measurement restriction patterns 1110 and 1115, the UE changes the channel state for the subframe corresponding to the ABS as the PDSCH can be scheduled. It will be possible to check. For example, the CQI report on the ABS section may be separately detected. Depending on the channel state, it may be a state in which the setting needs to be changed, and the measurement of the ABS may provide basic information for the operation.

Upon receiving the ABS pattern information 1120 through the measurement limit pattern 1105 for the ABS, the terminal may decode the received PDSCH based on this, but does not actually perform the measurement.

Table 6 below shows the transmission of ABS pattern information (or ABS power offset value) using the new measurement limit pattern.

Abs-SubframePatternConfig-r10 CHOICE { release NULL, setup SEQUENCE { Abs-MeasSubframeSet1-r10 MeasSubframePattern-r11, } }

Here, Abs-SubframePatternConfig-r10 is a measurement limit pattern for ABS.

Referring back to FIG. 3, following step S315, the UE performs the measurement (S320), the UE transmits the measurement result to the second base station (S325), and the terminal demodulates and based on the ABS pattern and the ABS power offset. As the decoding is possible, the second base station transmits downlink traffic to the terminal based on the measurement result (S330).

12 is a flowchart illustrating an operation of a base station transmitting frame pattern information for inter-cell interference coordination in a heterogeneous network system according to the present invention. The base station is the second base station of FIG. 3, and may be a macro base station, a femto base station, or a pico base station.

Referring to FIG. 12, the base station receives an ABS pattern for coordinating interference between different types of cells (eg, macro cell and pico cell) from an adjacent base station (S1200). The ABS pattern is configured to minimize or not give interference at all, and ABS is a coordination method of inter-cell interference based on TDM in which heterogeneous cells share time resources such as subframes. In this case, the ABS is a subframe capable of transmitting control information such as a PDCCH with limited power (or attenuated power), also referred to as non-zero power ABS.

For example, the ABS pattern may be received through the X2 interface.

The base station configures a measurement limit pattern for measurement to be performed by the terminal based on the received ABS pattern (S1205). A measurement limit pattern is constructed to avoid situations where measurement results can be severely affected by interference from neighboring base stations.

The measurement limit pattern includes a measurement limit pattern for RLM / RRM measurement and a measurement limit pattern for CSI measurement. The measurement limit pattern for RRM / RLM measurement must be configured in consideration of ABS pattern, while measurement limit for CSI measurement is required. The pattern is not limited to ABS patterns so that channel conditions can be evaluated at various locations as needed. In addition, two subframe sets may be defined and transmitted to the UE as a measurement restriction pattern for CSI measurement.

The base station transmits the measurement restriction pattern configured through the RRC dedicated signaling to the terminal, and transmits the ABS pattern to the terminal through the system information or the RRC dedicated signaling (S1210). The transmission of the measurement restriction pattern and the transmission of the ABS pattern may be performed simultaneously, the transmission of the measurement restriction pattern may be performed first, or the transmission of the ABS pattern may be performed first.

Since the base station knows the ABS pattern since the base station receives the ABS pattern from the neighboring base station, the base station can transmit the ABS pattern information of the neighboring base station to the terminal.

The base station may transmit the ABS pattern information using system information or RRC dedicated signaling. For example, the base station may add an ABS pattern to the system information and transmit it to the terminal through BCCH. As another example, ABS pattern information may be transmitted through RRC dedicated signaling. ABS pattern information can be transmitted similarly to the method of setting the measurement limit pattern for RRM / RLM measurement and CSI measurement.

In order to transmit ABS pattern information, a measurement limit pattern for CSI measurement may be used. If it is determined that the first measurement restriction pattern does not always coincide with the ABS pattern, an indicator indicating whether the first measurement restriction pattern is the same as or different from the ABS pattern may be transmitted together. Alternatively, a measurement limit pattern for ABS, which is a new measurement limit pattern, may be used.

The base station transmits downlink traffic to the terminal based on the measurement result performed by the terminal (S1215).

13 is a flowchart illustrating an operation of a terminal receiving frame pattern information for inter-cell interference coordination in a heterogeneous network system according to the present invention.

Referring to FIG. 13, the terminal receives the measurement restriction pattern from the base station through the RRC dedicated signaling, and receives the ABS pattern and the power offset value Δ _{ABS of the ABS} from the heterogeneous base station through the system information or the RRC dedicated signaling (S1300). ). The reception of the measurement restriction pattern and the reception of the ABS pattern (and the ABS power offset value) may be performed simultaneously, the reception of the measurement restriction pattern may be performed first, and the reception of the ABS pattern (and the ABS power offset value) may be performed first. May be

The terminal may receive the ABS pattern information and the power offset value of the ABS from the heterogeneous base station through system information or RRC dedicated signaling. The system information or the RRC dedicated signaling may include not only an ABS pattern but also an ABS power offset value or an ABS transmit power value itself.

When using the RRC-only signaling, ABS pattern information may be received similarly to a method of configuring and receiving a measurement limit pattern for RRM / RLM measurement and CSI measurement.

The ABS pattern can be received using the measurement limit pattern for CSI measurement, and if the first measurement limit pattern is determined not to always match the ABS pattern, it indicates whether the first measurement limit pattern is the same as or different from the ABS pattern. The indicator (pattern identification indicator) can be received together. Alternatively, the ABS pattern may be received using the measurement limit pattern for the ABS, which is a new measurement limit pattern.

The terminal performs the measurement using the received measurement restriction pattern, transmits the measurement result to the base station, and receives the downlink traffic based on this (S1305).

Using the ABS pattern information and the ABS power offset value, the base station can transmit traffic through scheduling and allocate transmission power. In this regard, the terminal may receive and decode the traffic transmitted by the base station using the ABS pattern information and the ABS power offset value. For example, the UE may receive a PDCCH or PDSCH through a subframe corresponding to the ABS.

14 is a flowchart illustrating an operation of a base station transmitting frame pattern information for inter-cell interference coordination in a heterogeneous network system according to the present invention. The base station is the first base station of FIG. 3 and may be a macro base station, a femto base station, or a pico base station.

Referring to Figure 14, the base station configures an ABS pattern for interference coordination between different types of cells (S1400). The base station configures the ABS pattern to minimize or not give interference to other neighboring base stations.

As an example of ABS according to the present invention, the ABS can transmit control information such as PDCCH with limited power (or attenuated power), and provides control information, data information, signaling, and system information necessary for the terminal for backward compatibility. It is a subframe that can be transmitted.

The base station transmits the configured ABS pattern to another neighboring base station (S1405). For example, the base station may transmit the above-described ABS pattern to another neighboring base station through the X2 interface.

The base station transmits the ABS pattern and the power offset value Δ _{ABS of the ABS} to the terminal through system information or RRC dedicated signaling (S1410).

Using the ABS pattern information and the ABS power offset value, the base station may transmit traffic through scheduling in a subframe corresponding to the ABS pattern, and allocate transmission power. Even if the UE receives the measurement restriction pattern, it does not know which subframe is ABS unless it receives the ABS pattern itself.

For example, the ABS pattern information and the power offset value of the ABS may be transmitted through the system information, and the base station may add the ABS pattern to the system information and transmit the ABS pattern information to the terminal through the BCCH. The system information may further include an ABS power offset value Δ _ABS as well as an ABS pattern. Alternatively, the system information 350 may include an ABS transmission power value itself.

As another example, the ABS pattern information and the ABS power offset value may be transmitted through the RRC dedicated signaling, and at this time, when transmitting the ABS pattern information (or the ABS power offset value) using the RRC dedicated signaling, measurement limitation for measuring the CSI Patterns can be used. In particular, the first measurement limit pattern may be set equal to the ABS pattern of the base station. Alternatively, an indicator (pattern identification indicator) indicating whether the first measurement restriction pattern is the same as or different from the ABS pattern may be included in the RRC dedicated signaling or the first measurement restriction pattern information and transmitted to the terminal. The pattern equality indicator may be transmitted or indicated together when informing of the measurement restriction pattern, or may be transmitted or indicated independently of the measurement restriction pattern. Alternatively, when transmitting ABS pattern information (or ABS power offset value) using RRC dedicated signaling, the base station may configure and transmit a new measurement limit pattern, and the new measurement limit pattern is a measurement limit pattern for CSI measurement, It may be a measurement limit pattern for RRM / RLM measurement or may be a new type of measurement limit pattern.

15 is a block diagram illustrating an apparatus for transmitting and receiving frame pattern information according to the present invention.

Referring to FIG. 15, the terminal 1500 includes a receiver 1505 and a measurement performer 1510 includes a transmitter 1515.

The receiver 1505 receives the measurement limit pattern from the second base station 1560 through RRC dedicated signaling, and receives the ABS pattern and the power offset value Δ _{ABS of the ABS} through system information or RRC dedicated signaling. From). The reception of the measurement restriction pattern and the reception of the ABS pattern (and the ABS power offset value) may be performed simultaneously, the reception of the measurement restriction pattern may be performed first, and the reception of the ABS pattern (and the ABS power offset value) may be performed first. May be It is also possible to receive the ABS pattern of the first base station from the second base station.

The receiver 1505 may receive the ABS pattern information and the power offset value of the ABS by using system information or RRC dedicated signaling. The system information or the RRC dedicated signaling may include not only an ABS pattern but also an ABS power offset value or an ABS transmit power value itself.

When using the RRC dedicated signaling, the receiver 1505 may receive ABS pattern information similar to a method of configuring and receiving a measurement limit pattern for RRM / RLM measurement and CSI measurement.

The receiver 1505 may receive the ABS pattern using the measurement restriction pattern for CSI measurement, and if it is determined that the first measurement restriction pattern does not always match the ABS pattern, whether the first measurement restriction pattern is the same as the ABS pattern. Alternatively, an indicator indicating whether the pattern is different may be received together. Alternatively, the receiver 1505 may receive an ABS pattern using a measurement limit pattern for ABS, which is a new measurement limit pattern.

The measurement performing unit 1510 performs the measurement by using the received measurement restriction pattern.

The transmitter 1515 transmits the measured result to the second base station 1560.

The receiver 1505 receives downlink traffic based on the measurement result, and in particular, may receive a PDCCH or PDSCH through a subframe corresponding to the ABS using the ABS pattern information and the ABS power offset value. Using the ABS pattern information and the ABS power offset value, the second base station 1560 may transmit traffic through scheduling and allocate transmission power. The receiver 1505 may receive the traffic from the second base station 1560 using the ABS pattern information and the ABS power offset value, and may decode the traffic.

Referring to FIG. 15, the first base station 1530 includes an ABS pattern configuration unit 1535 and a transmission unit 1540.

The ABS pattern configuring unit 1535 configures an ABS pattern for interference coordination between different types of cells. The ABS pattern configuration unit 1535 configures an ABS pattern so as to minimize or not give interference to the second base station 1560 at all. The ABS is a subframe capable of transmitting control information such as PDCCH with limited power (or attenuated power) and transmitting control information, data information, signaling, and system information necessary for the terminal 1500 for backward compatibility. .

The transmitter 1540 transmits the configured ABS pattern to the second base station 1560. For example, the transmitter 1540 may transmit the above-described ABS pattern to the second base station 1560 through the X2 interface.

The transmitter 1540 transmits the ABS pattern and the power offset value Δ _{ABS of the ABS} to the terminal 1500 through system information or RRC dedicated signaling.

The transmitter 1540 may transmit a low power signal in a subframe corresponding to the ABS based on the ABS pattern and the power offset value of the ABS. The transmitter 1540 may transmit traffic through scheduling in a subframe corresponding to an ABS pattern that receives minimal interference from the first base station 1530 by using ABS pattern information and the ABS power offset value, and allocates transmission power. can do. Even if the UE 1500 receives the measurement restriction pattern, the UE 1500 does not know which subframe is ABS unless the ABS pattern itself is received. For example, the ABS pattern information and the power offset value of the ABS may be transmitted through the system information, and the transmitter 1540 may add the ABS pattern to the system information and transmit the ABS pattern information to the terminal 1500 through BCCH. The system information may further include an ABS power offset value Δ _ABS as well as an ABS pattern. Alternatively, the system information may include the ABS transmission power value itself.

The transmitter 1540 may transmit the ABS pattern information and the ABS power offset value through RRC dedicated signaling, and may use a measurement limit pattern for CSI measurement. In particular, the first measurement limit pattern may be set in the same manner as the ABS pattern of the first base station 1530. Alternatively, an indicator (pattern identification indicator) indicating whether the first measurement restriction pattern is the same as or different from the ABS pattern may be included in the RRC-only signaling or the first measurement restriction pattern information and transmitted to the terminal 1500. The pattern equality indicator may be transmitted or indicated together when informing of the measurement restriction pattern, or may be transmitted or indicated independently of the measurement restriction pattern. Alternatively, when transmitting ABS pattern information (or ABS power offset value) using RRC dedicated signaling, the transmitter 1540 may configure and transmit a new measurement limit pattern, and the new measurement limit pattern may be measured for CSI measurement. It may be a limiting pattern, a measurement limiting pattern for RRM / RLM measurement, or a new type of measurement limiting pattern.

Referring to FIG. 15, the second base station 1560 includes a receiving unit 1565, a measurement limit pattern configuring unit 1570, and a transmitting unit 1575.

The receiver 1565 receives an ABS pattern from the first base station 1530 for coordinating interference between different kinds of cells (eg, macro cell and pico cell). In this case, the ABS is a subframe capable of transmitting control information such as a PDCCH with limited power (or attenuated power), also referred to as non-zero power ABS. For example, the ABS pattern may be received through the X2 interface.

The measurement restriction pattern configuration unit 1570 configures a measurement restriction pattern for measurement to be performed by the terminal 1500 based on the received ABS pattern. The measurement restriction pattern is configured to avoid a situation in which the measurement result may be severely affected by the interference from the first base station 1530. In this case, the measurement limit pattern includes a measurement limit pattern for RLM / RRM measurement and a measurement limit pattern for CSI measurement. The measurement limit pattern for RRM / RLM measurement is necessarily configured in consideration of an ABS pattern, The measurement limit pattern is not limited to the ABS pattern so that channel conditions can be evaluated at various locations as needed. In addition, two subframe sets may be defined and transmitted to the UE 1500 in the measurement restriction pattern for CSI measurement.

The transmitter 1575 transmits the measurement restriction pattern configured through the RRC dedicated signaling to the terminal 1500.

The transmitter 1575 transmits the ABS pattern of the first base station 1530 to the terminal 1500 through system information or RRC dedicated signaling. The transmission of the measurement restriction pattern and the transmission of the ABS pattern of the first base station 1530 may be performed simultaneously, the transmission of the measurement restriction pattern may be performed first, and the transmission of the ABS pattern of the first base station 1530 may be performed first. May be

The transmitter 1575 may transmit ABS pattern information of the first base station 1530 by using system information or RRC dedicated signaling. For example, the transmitter 1575 may add the ABS pattern of the first base station 1530 to the system information and transmit the ABS pattern to the terminal 1500 through the BCCH. As another example, the transmitter 1575 may transmit ABS pattern information of the first base station 1530 through RRC dedicated signaling, and similarly to a method of setting measurement limit patterns for RRM / RLM measurement and CSI measurement. ABS pattern information can be transmitted.

The transmitter 1575 may use a measurement limit pattern for measuring CSI to transmit ABS pattern information of the first base station 1530. If it is determined that the first measurement restriction pattern does not always match the ABS pattern, the transmission unit 1575 transmits an indicator (pattern identification indicator) indicating whether the first measurement restriction pattern is the same as or different from the ABS pattern. Can be. Alternatively, the transmission unit 1575 may use a measurement limit pattern for ABS, which is a new measurement limit pattern.

The transmitter 1575 transmits downlink traffic to the terminal 1500 based on the measurement result performed by the terminal 1500.

In the above-described exemplary system, the methods are described on the basis of a flowchart as a series of steps or blocks, but the present invention is not limited to the order of the steps, and some steps may occur in different orders or simultaneously . It will also be understood by those skilled in the art that the steps shown in the flowchart are not exclusive and that other steps may be included or that one or more steps in the flowchart may be deleted without affecting the scope of the invention.

The above-described embodiments include examples of various aspects. While it is not possible to describe every possible combination for expressing various aspects, one of ordinary skill in the art will recognize that other combinations are possible. Accordingly, it is intended that the invention include all alternatives, modifications and variations that fall within the scope of the following claims.

Claims (15)

In a method for coordinating intercell interference by a base station in a heterogeneous network system,
Based on time division multiplexing, the ABS pattern, which is a pattern to which an Almost Blank Subframe (hereinafter referred to as ABS) is applied, is applied to prevent a subframe scheduled for transmission of a heterogeneous eNB from causing interference with the base station. Receiving from a heterogeneous base station;
Configuring a measurement limit pattern based on the ABS pattern, the measurement limit pattern being a pattern in which a subframe in which measurement is performed by a terminal is restricted; And
And transmitting the ABS pattern and the measurement restriction pattern to the terminal. The method of claim 1,
The ABS pattern and the measurement limit pattern is included in a system information block is transmitted to the terminal, characterized in that for transmitting to the terminal. 3. The method of claim 2,
And the system information further comprises a power offset value used to allocate transmit power in a subframe corresponding to the ABS. The method of claim 1,
The ABS pattern and the measurement limit pattern are inter-cell interference coordination method, characterized in that transmitted to the terminal through RRC dedicated signaling (Radio Resource Control Dedicated Signaling). The method of claim 1,
The measurement restriction pattern is a measurement restriction pattern for measuring channel state information (CSI),
At least one of the measurement restriction patterns for the CSI measurement is set to the same pattern as the ABS pattern. The method of claim 1,
The measurement limit pattern is a measurement limit pattern for CSI measurement,
And transmitting to the terminal an indicator indicating whether the measurement limit pattern for the CSI measurement and the ABS pattern are set to the same. The method of claim 1,
The ABS pattern is represented by a bitmap,
The inter-cell interference coordination method, characterized in that the subframe position corresponding to the ABS is represented by 1. A base station for coordinating intercell interference in a heterogeneous network system,
A receiver configured to receive an ABS pattern from the heterogeneous base station, which is a pattern to which a subframe in which transmission power is attenuated is applied so that a subframe scheduled for signal transmission of the heterogeneous base station does not interfere with the base station based on time division multiplexing;
A measurement restriction pattern configuration unit configured to configure a measurement restriction pattern, which is a pattern in which a subframe in which measurement is performed by a terminal, is restricted based on the ABS pattern; And
A base station comprising a transmitter for transmitting the ABS pattern and the measurement restriction pattern to the terminal. The method of claim 8,
Wherein the transmission unit comprises:
And the ABS pattern and the measurement limit pattern are included in a system information block and transmitted to the terminal. The method of claim 9,
The system information,
And a power offset value used for allocating transmit power in the subframe corresponding to the ABS. The method of claim 8,
Wherein the transmission unit comprises:
The base station, characterized in that for transmitting the ABS pattern and the measurement restriction pattern to the terminal through the RRC dedicated signaling. The method of claim 8,
The measurement limit pattern is a measurement limit pattern for CSI measurement,
The measurement limit pattern configuration portion,
The base station, characterized in that at least one of the measurement restriction pattern for measuring the CSI is set to the same pattern as the ABS pattern. The method of claim 8,
The measurement limit pattern is a measurement limit pattern for CSI measurement,
Wherein the transmission unit comprises:
The base station, characterized in that for transmitting the indicator indicating whether the measurement restriction pattern for the CSI and the ABS pattern is set to the same. In a method for coordinating intercell interference by a terminal in a heterogeneous network system,
Based on time division multiplexing, the ABS pattern, which is a pattern to which the transmission power attenuated subframe (ABS) is applied, and the subframe on which measurement is limited, so that the subframe scheduled for signal transmission of the heterogeneous base station does not interfere with the base station. Receiving a measurement measurement pattern from the base station or the heterogeneous base station;
Performing a measurement based on the measurement restriction pattern; And
And receiving downlink traffic from the heterogeneous base station based on a result of the measurement at the transmission power allocated by the heterogeneous base station based on the ABS pattern. A terminal for coordinating interference between cells in a heterogeneous network system,
Based on time division multiplexing, the ABS pattern, which is a pattern to which the transmission power attenuated subframe (ABS) is applied, and the subframe on which measurement is limited, so that the subframe scheduled for signal transmission of the heterogeneous base station does not interfere with the base station. A receiving unit for receiving a measurement measurement pattern from the base station or the heterogeneous base station; And
It includes a measurement performing unit for performing the measurement based on the measurement restriction pattern,
The receiver may further comprise:
And receiving downlink traffic from the heterogeneous base station based on a result of the measurement at the transmission power allocated by the heterogeneous base station based on the ABS pattern.

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