KR101964220B1 - Apparatus and method for allocating resource in overlapped wierless network - Google Patents

Abstract

The present invention determines a number of subbands to be allocated in the first cell based on interference between a first cell managed by the base station and at least one second cell adjacent to the first cell in a wireless communication network And transmitting information on the determined number to a network management apparatus managing a plurality of base stations, receiving information on a start position of a sub-band to start allocation restriction in the first cell from the network management apparatus, Allocates to the at least one terminal in the first cell the remainder excluding the determined number of subbands starting from the subbands according to the information on the start position among all the subbands allocable in one cell, And the information about the position is changed according to the determined number.

Description

[0001] APPARATUS AND METHOD FOR ALLOCATING RESOURCE IN OVERLAPPED WIERLESS NETWORK [0002]

The present invention relates to a resource allocation method and apparatus in a wireless communication system, and more particularly, to a method for performing resource allocation and resource management in consideration of inter-cell interference in an overlapping wireless network environment.

Recently, with the increase of demand for data service in wireless communication network, wireless communication service providers are operating overlapped network structure in a region where traffic demand is concentrated for network capacity increase and traffic load balancing. That is, as shown in FIG. 1, a micro base station such as a micro base station or a pico base station is installed and operated in a cell managed by a conventional macro base station (hereinafter referred to as a macro cell). Accordingly, a superposed network structure in which the macro cell area and the cell managed by the small base station (hereinafter, referred to as a small cell) overlap each other is formed.

On the other hand, when the same frequency is used between adjacent cells in a wireless communication network, an inter-cell interference problem occurs. In order to solve the above problem, an inter-cell interference mitigation technique is used. Inter-cell interference mitigation techniques include inter-cell interference co-ordination (ICIC) through frequency domain inter-cell cooperation, interference control techniques through time domain inter-cell cooperation, and partial frequency reuse techniques FFR, Fractional Frequency Reuse).

Interference control schemes through frequency domain inter-cell co-operation allow a plurality of base stations to coordinate inter-cell transmission power patterns in the frequency domain, and each base station performs scheduling according to the inter-cell transmission power pattern to mitigate inter- Technique.

Interference control scheme through cooperation between time domain cells is a technique in which a plurality of base stations coordinate transmission power or time resources between cells in a time domain and each base station performs scheduling in a coordinated time domain to mitigate inter-cell interference .

The partial frequency reuse technique can improve the performance at the cell boundary by considering the frequency reuse factor and the inter-cell interference. The partial frequency reuse technique divides the entire subcarrier into a plurality of subbands, It is a technique to mitigate co-channel interference using only some subbands.

The 3GPP UTRA / UTRAN Release 10 specification adds elements to support interference control techniques through time domain inter-cell cooperation. In this specification, an ABS (Almost Blank Subframe) is a subframe that performs low power transmission or no transmission in a specific physical channel and performs only a partial operation. Each base station determines the ABS pattern of the macro base station through tuning, and the macro base station whose ABS pattern is determined performs scheduling according to the determined ABS pattern.

Meanwhile, the above-described inter-cell interference problem may occur between cells belonging to the overlapping wireless network environment, which will be described with reference to FIG.

2 is an exemplary diagram for explaining an inter-cell interference problem due to the extension of a small cell in a wireless communication system of a superposed wireless network structure.

As shown in FIG. 2, when a small base station is installed and operated so that a macro cell area and a cell area overlap each other, a cell boundary area 202 is generated around a cell managed by the small base station, that is, a small cell. When a terminal belonging to a peripheral base station (hereinafter referred to as a peripheral base station terminal) is located in the cell boundary region 202, the channel quality of the peripheral base station terminal deteriorates due to interference from the small base station. Also, when a terminal belonging to a small base station (hereinafter referred to as a small base station terminal) is located in the cell economical area 202, the channel quality of the small base station terminal deteriorates due to interference from existing macro base stations.

As the number of small base stations installed and operated in the above environment increases, the cell boundary region 202 is enlarged in the existing macro base station network. Therefore, interference problems caused by the small base station to terminals belonging to the existing macro base station, The interference problem caused from the base station to the small base station terminal is increased.

Although the interference control technique known in the art for solving the inter-cell interference problem in the overlapping wireless network structure as described above can be used, the following problems may occur.

For example, when an interference control scheme is applied to a wireless communication system having a superposed wireless network structure through inter-cell cooperation, deterioration of interference control performance due to incompatibility between the existing macro network and the small base station network occurs, or In order to ensure compatibility, it may be necessary to change or improve existing macro networks and small networks.

Here, the macro network means a communication network composed of a plurality of macrocells constituting a superposed wireless network structure, and the small network means a communication network composed of a plurality of small cells constituting the superposed wireless network structure. The same shall apply hereinafter.

In the case of applying the interference control scheme through the inter-cell cooperation to the wireless communication system of the overlapping wireless network structure, considering the increase of the number of base stations or cells due to the installation of a small base station, Excessive information exchange between small networks and small networks can be induced.

On the other hand, in the case of applying the static partial frequency reuse technique in the wireless communication system of the overlapping wireless network structure, there is a problem that it is difficult to reassign the frequency band adaptively according to the instantaneous user distribution. Even if the frequency band is adaptively allocated as much as possible dynamically using the channel state information of the users and the allocation information of neighboring cells in the partial frequency reuse technique, the macro base station and the small base station or the macro It can cause excessive information exchange between the network and the small network.

The present invention provides a method and apparatus for performing resource allocation in a wireless communication system of a superposed wireless network structure.

The present invention provides a method and apparatus for performing resource management in a wireless communication system of a superposed wireless network structure.

The present invention provides a method for mitigating interference between a macro network and a small network in a wireless communication system of a superposed wireless network structure.

The present invention provides a method and apparatus for performing resource allocation and resource management so as to mitigate interference between a macro network and a small network in a wireless communication system of a superposed wireless network structure.

The present invention provides a method and an apparatus for mitigating interference from a newly added small base station to a base station installed and operating in a wireless communication system of a superposed wireless network structure.

The present invention provides a method and apparatus for mitigating interference from a base station installed and operating in a wireless communication system of a superposed wireless network structure to a newly installed small base station.

In providing the above measures, the present invention provides a method for controlling an aggressor base station in a time domain in which an aggressor base station allocates constraints for interference mitigation to a victim base station, A method and apparatus for determining the ratio of frequency domain radio resources is provided.

The present invention provides a method and apparatus for reducing the amount and frequency of information exchanges between network entities constituting a wireless communication network in providing the above measures.

The present invention provides a method and apparatus for adaptively applying an interference mitigation technique to reflect the degree of interference in providing the above measures.

A method according to an embodiment of the present invention comprises: CLAIMS 1. A method for allocating resources in a wireless communication network, the method comprising: allocating resources in a first cell based on interference between a first cell managed by the base station and at least one second cell adjacent to the first cell; A step of transmitting information on the determined number to a network management apparatus which manages a plurality of base stations; and a step of transmitting, from the network management apparatus, The method comprising the steps of: receiving, from all sub-bands allocable in the first cell, information excluding the determined number of sub-bands starting from a sub-band according to information on the start position, To at least one terminal, and the information on the start position is changed according to the determined number .

According to another embodiment of the present invention, there is provided a method comprising: A method for transmitting information for resource allocation in a wireless communication network, the method comprising: transmitting, from a first one of a plurality of base stations, a first cell managed by the first base station and at least one The method comprising the steps of: receiving information on the number of subbands to be allocated in the first cell based on interference between the first and second cells; And transmitting information on a start position of the determined subband to the first base station. The method of claim 1, further comprising: determining a start position of the first sub- The rest of the subbands are allocated to at least one terminal in the first cell starting from the subbands according to the information, The information is characterized in that depending on the determined number.

An apparatus according to an embodiment of the present invention includes: CLAIMS 1. A base station in a wireless communication network, the base station comprising: a transmitter, a receiver, and a unit for limiting an assignment in the first cell based on interference between a first cell managed by the base station and at least one second cell adjacent to the first cell, A control unit for controlling the transmitting unit to transmit the information on the determined number to a network management apparatus for managing a plurality of base stations from the network management apparatus through the receiving unit, The mobile station apparatus comprising: a mobile station for receiving information on a start position of a sub-band to be started in a first cell, And a resource allocation unit for allocating the start position to at least one terminal in the first cell, The number of features in the dependent.

According to another embodiment of the present invention, there is provided an apparatus comprising: A network management apparatus in a wireless communication network, the apparatus comprising: a first base station, the first base station being controlled by the first base station and the second cell adjacent to the first cell, A control unit for determining a start position of a subband to start allocation restriction in the first cell based on the received information; And a transmitter for transmitting information on a start position of a determined sub-band to the first base station, wherein the sub-band is a sub-band based on information on the start position among all sub-bands allocable in the first cell, The remaining information is allocated to at least one terminal in the first cell, and information on the starting position is allocated to the terminal according to the determined number Referred to as load characteristics.

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According to the present invention, inter-cell interference can be mitigated in an overlapping wireless network environment.

According to the present invention, there is an advantage that resource allocation and resource management can be efficiently performed in consideration of inter-cell interference in an overlapping wireless network environment.

Also, according to the present invention, there is an advantage that a small base station installed in a coverage area of an existing wireless network can interfere with the existing network or interference between the existing network and the small base station can be mitigated.

In addition, according to the present invention, it is possible to reduce the interfacing burden by reducing the frequency and amount of information exchange between entities in an overlapping wireless network environment.

In addition, according to the present invention, an interference-based base station is located around the interference-based base station and determines interference ratio-restricted radio resource ratio adaptively based on the distribution of other base station terminals affected by the interference by the interference- Thereby increasing the radio resource efficiency of the network.

1 is a diagram showing a wireless communication system of a superposition wireless network structure,
2 is an exemplary diagram for explaining a problem of intercell interference due to the extension of a small cell in a wireless communication system of a superposition wireless network structure
FIG. 3 is a schematic diagram of a multiple communication network structure according to an embodiment of the present invention. FIG.
FIG. 4 illustrates a subband allocation operation for a small base station to control interference to a neighbor base station according to an embodiment of the present invention;
FIG. 5 is a flowchart illustrating a procedure for determining a number of allocated subbands by a small base station according to an embodiment of the present invention;
FIG. 6 is a flowchart illustrating an interference control process performed in a small network management apparatus according to an embodiment of the present invention. FIG.
FIG. 7 is a flowchart for explaining a procedure for estimating the number of peripheral base station terminals subject to interference control and determining a neighboring base station list according to an exemplary embodiment of the present invention;
8 is a signal flow diagram illustrating an information exchange procedure between communication network elements for interference control according to an embodiment of the present invention;
FIG. 9 is a signal flow diagram illustrating a process of exchanging information between a small-sized network management apparatus and a small-sized base station for the allocation constrained sub-band position adjustment according to an embodiment of the present invention;
10 is a block diagram illustrating an internal configuration of a small base station according to an embodiment of the present invention.
11 is a block diagram illustrating an internal configuration of a small-sized network management apparatus according to an embodiment of the present invention.
12 is a block diagram illustrating an internal configuration of a macro base station according to an embodiment of the present invention;
13 is a block diagram illustrating an internal configuration of a macro network management apparatus according to an embodiment of the present invention.
FIG. 14 is a flowchart illustrating an interference control procedure of a macro base station using an interference control technique through time domain inter-cell cooperation according to an embodiment of the present invention;
FIG. 15 is a flowchart for explaining a process of determining a number of allocation constraint frames using a cooperative interference control scheme in a macro-base station according to an embodiment of the present invention; FIG.
16 is a flowchart for explaining a method for estimating the number of interference-protected terminals based on a reference signal strength using an interference control technique through time-domain inter-cell cooperation according to an embodiment of the present invention;
FIG. 17 is a flowchart for explaining a method of estimating the number of interference-protected terminals based on a reference signal quality using an interference control technique through time-domain inter-cell cooperation according to an embodiment of the present invention; FIG.
FIG. 18 is a diagram for explaining an information exchange process for inter-network interference control function when an interference control scheme is applied through cooperation between time domain cells according to an embodiment of the present invention; FIG.
FIG. 19 is a block diagram illustrating an internal configuration of a macro base station using an interference control technique through time domain inter-cell cooperation according to an embodiment of the present invention;
20 is a flowchart for explaining a process of determining an allocated constrained radio resource ratio of an interference-causing base station in a wireless communication system of a superposed wireless network structure according to an embodiment of the present invention.

Hereinafter, the operation principle of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and these may be changed according to the intention of the user, the operator, or the like. Therefore, the definition should be based on the contents throughout this specification.
FIG. 3 is a schematic diagram of a multiple communication network structure according to an embodiment of the present invention. 3 (a) and 3 (b), the multiple communication network includes a core network 320 and a radio access network 310. The wireless access network 310 includes at least one macro base station 312 and at least one small base station 314. The at least one macro base station 312 and the at least one small base station 314 are installed / operated in overlapping coverage areas.
The core network 320 includes a communication network management apparatus (Element Management System) 326. The communication network management apparatus 326 includes a system for monitoring and controlling communication network equipment including base station equipment. A macro network management device 322 for managing a macro base station in the network and a small network management device 324 for managing a small base station in the network are separately provided or a single communication network Management device 326 may be present.
Each macro base station and each small base station has an interface with a communication equipment management system that manages the base station. When the macro base station communication equipment management system and the small base station communication equipment management system exist as separate entities, they have an interface between the entities. In the following description, it is assumed that a function included in the core network among the inter-cell interference mitigation functions proposed in the embodiment of the present invention exists in the network equipment management system. However, the functions included in the core network may be a separate network entity or another It is also possible to exist in the network entity.

4 is a diagram illustrating a subband allocation operation for a small base station to control interference with a neighbor base station according to an embodiment of the present invention.

Referring to FIG. 4, in step 401, the small base station confirms whether the information related to the allocation constrained subband for each small base station, for example, the allocation constrained subband position information for each small base station, is received from the small network management apparatus. The information is information used for determining the allocation constraint subband for which the small base station is to prohibit the resource allocation, and the small network management apparatus generates and transmits the generated information to the small base station in accordance with the established procedure. The process of the small network management apparatus to generate allocation constrained subband position information for each base station will be described later with reference to the related drawings.

If it is determined in step 401 that the allocation constrained subband position information for each small base station has been received, the small base station proceeds to step 403 and allocates its own allocation After updating the start position of the constrained subband, the flow advances to step S405.

If it is determined in step 401 that the allocation constrained subband position information for each small base station is not received, the small base station maintains its allocated constrained subband start position to the previous value, and then proceeds to step 405 do. If the previous value does not exist, a predefined initial value may be used.

In step 405, the small base station determines the number of allocated constrained subbands, and then proceeds to step 407. The allocation constrained subbands are determined according to a predetermined procedure of the small base station, and the process of determining the allocation constrained subbands will be described later with reference to the related drawings.

In step 407, the small base station determines the assigned constrained subband based on the allocated constrained subband start position updated or held in steps 401 and 403 and the allocated constrained subband number determined in step 405, (409).

In step 409, the small base station performs resource allocation to the terminal that is provided with the service to itself. At this time, the small base station does not allocate downlink resources to the terminal in the allocation constrained subband, but allocates downlink resources to the terminal in the remaining subbands.

In the case of using the resource allocation method according to an embodiment of the present invention as described with reference to FIG. 4, that is, when the small base station limits the resource allocation for data transmission in the allocation constrained subband, The interference from the small base station to the terminal performing communication with the neighbor base station of the small base station (i.e., the neighbor base station terminal) is eliminated, and thus the channel quality for the terminal performing communication with the neighbor base station in the sub- . At this time, the greater the degree of proximity of the terminal that performs communication with the neighbor base station of the small base station to the small base station, the greater the effect of channel quality improvement in the sub-band.

Meanwhile, the UE according to an embodiment of the present invention measures the channel quality for each subband and reports the channel quality for each subband to the serving BS. The serving BS reflects the channel quality of each subband reported from the MSs and performs subband scheduling for each subband. Therefore, as the terminal performing communication with the neighbor base station is close to the small base station, the neighbor base station has a high priority in the resource allocation determination process for the sub-band, a relatively large number of radio resources are allocated, A high transmission rate improvement effect is obtained.

FIG. 5 is a flowchart illustrating a procedure for determining a number of allocated subbands by a small base station according to an exemplary embodiment of the present invention. Referring to FIG.

In steps 501a to 503c, the small base station obtains the number of active terminals in the peripheral base station, obtains the number of active terminals belonging to the small base station, The number of interference control target terminals of the neighboring base stations located in the neighboring base stations is estimated.

At step 503, the small base station transmits at least one of the number of active terminals in the peripheral base station, the number of active terminals belonging to itself, and the number of interference control target terminals of the peripheral base station obtained in steps 501a to 501c To determine the number of assigned constraint subbands.

For example, the small base station increases the number of allocated subbands as the number of neighboring base station interference control terminals increases, and decreases the number of allocated subbands as the number of active terminals belonging to the neighbor base station or the number of active terminals belonging to the neighboring base station decreases. Equation (1) shows an example in which the small base station determines the number of allocated subbands according to an embodiment of the present invention.

The definition of the related parameters in Equation (1) is as follows.

N _SB : Assignment constraint subband number

G: set of neighboring base stations affected by interference of small base station

N _aggressor : Number of active terminals in a small base station

N _victim [i]: Number of active terminals in neighbor base station i

N _protected [i]: Number of terminals to be protected in peripheral base station i

N _subband : Number of subbands used by small base stations

Equation (1) is an example of determining the number of allocated constraint subbands according to an embodiment of the present invention, but the present invention is not limited thereto. That is, Equation (1) is determined by the ratio of the number of active subscribers in the neighbor base station to the number of active subscribers in the small base station, It is possible to change within the basic idea of becoming. For example, the predefined upper limit or lower limit value, quantization, etc. can be applied. Meanwhile, the number of active terminals of the base station is determined by a traffic load state of the base station including physical resource block usage Can be replaced with other values representing < RTI ID = 0.0 >

The small base station updates the moving average value of the number of active terminals from the number of active terminals in the small base station obtained through the above process. Here, the moving average value can use various averages including simple moving average and exponential moving average. The small base station transmits the moving average value of the number of active terminals to the small network management apparatus according to a set procedure. This will be described later with reference to related drawings.

FIG. 6 is a flowchart illustrating an interference control process performed in a small network management apparatus according to an embodiment of the present invention. Referring to FIG.

In step 601a, the small network management apparatus obtains and manages information on the number of active state terminals per macro base station from the macro network management apparatus.

In step 601b, the small network management apparatus obtains and manages information including a list of peripheral base stations of the small base station and a moving average value of the number of active terminals from each small base station to be managed.

In step 603, the small network management apparatus calculates, based on the information obtained in steps 601a and 601b, the average number of active terminals in the peripheral base station included in the peripheral base station list of the small base station Generates information on the value list, and delivers the generated information to the small base station.

The operation described with reference to FIG. 6 is based on an environment in which a macro network management apparatus 322 for managing a macro base station and a small network management apparatus 324 exist separately, as described with reference to FIG. 3 (b) Respectively. As described with reference to FIG. 3 (a), in the case of a single communication network management apparatus, information exchange operation between the macro network management apparatus and the small network management apparatus can be omitted.

7 is a flowchart illustrating a procedure for estimating the number of peripheral base station terminals subject to interference control and determining a neighboring base station list according to an exemplary embodiment of the present invention.

When a small base station generates an outbound handover event from the small base station to the neighbor base station or an inbound handover event from the neighbor base station to the small base station, And the number of handover events for each base station. This will be described in more detail as follows.

In step 701, the small base station determines whether a handover event has occurred. If a handover event has occurred, the small base station proceeds to step 703, otherwise proceeds to step 711.

In step 703, the small base station determines whether the current handover event is an inbound handover event or an outbound handover event. If the handover event is an inbound handover event, the small base station proceeds to step 705a, The process proceeds to step 7050b.

In step 705a, the small base station determines whether the source base station is included in the base station list, and if the source base station is not included in the base station list, proceeds to step 707 to add the source base station to the base station list, ).

In step 705b, the small base station determines whether the target base station is included in the base station list, and if the target base station is not included in the base station list, proceeds to step 707 to add the target base station to the base station list, The process proceeds to step S709.

In step 709, the small base station increases the number of handover event occurrences by one, and then proceeds to step 711. [

In step 711, the small base station determines whether the handover event statistical period has expired, and if not expired, performs steps 701 to 709, and if it has expired, proceeds to step 713 .

In step 713, the small base station generates and stores handover event statistical information during a predefined time period, i.e., a handover event statistical period. Also, the small base station generates the neighbor base station list based on the handover event statistics. That is, the small base station determines the base station list included in the handover event statistical information as the neighbor base station of the small base station. The list of peripheral base stations of the small base station is a list of neighbor base stations for the interference control technique proposed in the present invention, and is information distinguished from the neighbor base list for the handover or self organizing network (SON) function.

8 is a signal flow diagram illustrating an information exchange procedure between communication network elements for interference control according to an embodiment of the present invention.

The macro base station transmits the number of active state terminals to the macro network management apparatus when the predefined condition is satisfied (step 801). The predefined condition may be, for example, when the macro network management apparatus managing the macro base station requests the macro base station to report the number of active state terminals, when a predefined time comes, when a predefined event occurs Lt; / RTI &gt; If a predefined event occurs, for example, the rate of change of the number of active terminals may be outside the predefined range.

The macro network management device collects and manages the number of active terminals transmitted by the macro base station to be managed.

If the predefined condition is satisfied, the small base station transmits the moving average value of the neighbor base station list and the active terminal number in the small base station to the small network management apparatus (step 805). The list of neighbor base stations may be obtained, for example, as described with reference to FIG.

The predefined condition may be a case where a small network management apparatus managing the small base station requests reporting of the information to the small base station, a predefined time comes, or a predefined event occurs. For example, if the predefined event occurs, the moving average value change rate of the active terminal number or the predefined rate of the configuration base station change rate in the neighbor base station list may be out of the predefined range.

The small network management apparatus collects and manages a moving average value of the number of active terminals received from the managed small base station and a neighbor base station list.

The small network management apparatus retrieves the number of users of the base station included in the list of neighbor base stations of the small base station in the database of the number of active users per base station and transmits information on the number of active terminals per the base station to the small base station ))do. The database can be managed in the form of a table.

The information exchange process described with reference to FIG. 8 is an information exchange process in the case where the small network management apparatus and the macro network management apparatus exist independently as described with reference to FIG. 3 (b).

In the case of one communication network management apparatus as described with reference to FIG. 3 (a), the process of exchanging information between the small network management apparatus and the macro network management apparatus may be omitted.

FIG. 9 is a signal flow diagram illustrating a process of exchanging information between a small-sized network management device and a small-sized base station for the allocation constrained subband position adjustment according to an embodiment of the present invention.

The small base station transmits information on the allocation constrained bandwidth number to the small network management apparatus (step 901). The allocation constrained subband number may be obtained through the process described with reference to FIG.

The small network management device collects and stores information on the number of allocated constraint subbands transmitted from the small base station to be managed. The small network management apparatus adjusts the allocation constraint band position of each small base station in consideration of the number of allocation constraint subbands per small base station. The small network management apparatus transmits information on the allocation constrained subband position for each small base station to the corresponding small base station (step 903).

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

10, a small base station according to an embodiment of the present invention includes an allocation constrained subband decision unit 1010, a handover event statistics processing unit 1020, a peripheral base station management unit 1030, an active terminal statistics processing unit 1040 An interference control unit 1050, a small network management apparatus interface 1060, a resource allocation unit 1070, a physical layer processing unit 1080 and an RF (Radio Frequency) processing unit 1090.

The allocation constrained subband decision unit 1010 receives the information on the allocation constrained subband number and the allocation constrained subband position from the interference controller 1050. When the resource allocation unit 1070 allocates the radio resource to the terminal Determines a subband to limit resource allocation, and transmits information on the determined subband to resource allocator 1070. [

The handover event statistics processor 1020 processes handover event information generated during a predetermined time interval. That is, the handover event statistics processor 1020 generates statistical information on the number of handover occurrences of the base station and the base station in which the handover event has occurred, and transmits the generated statistical information to the interference controller 1050.

The neighboring base station management unit 1030 receives the statistical information related to the handover event from the interference control unit 1050 and updates the peripheral base station list. More specifically, the neighbor base station management unit 1030 removes a base station from which a handover event has not occurred during a predefined time interval from the previous neighbor base station list, from the neighbor base station list, The base station that generated the event is added to the neighbor base station list. Also, the neighbor base station management unit 1030 transmits the updated neighbor base station list to the interference control unit 1050. [

The active terminal statistics processor 1040 performs statistical processing on the number of active terminals in the small base station for a predetermined time interval and transmits the result of the performance to the interference controller 1050.

The interference controller 1050 receives statistical information related to the handover event from the handover event statistics processor 1020 and stores the statistical information.

When the predefined condition is satisfied, the interference controller 1050 delivers the handover event statistical information to the small network management device interface 1060.

The interference controller 1050 transmits the statistical information related to the handover event to the peripheral base station controller 1030 and receives and stores the peripheral base station list from the peripheral base station controller 1030. [

The interference controller 1050 receives the information on the number of active terminals from the active terminal statistics processor 1040, updates the moving average value of the number of active terminals, and transmits the updated result to the small network management device interface 1060. [ .

The interference controller 1050 transmits the list of peripheral base stations to the small network management device interface 1060 and receives information on the number of active terminals of the peripheral base station from the small network management device interface 1060 and stores the information.

The interference controller 1050 generates and stores information on the number of allocated constraint subbands on the basis of the number of terminals to be protected, the number of active terminals in the neighbor base station, and the number of active terminals in the small base station, To the department.

The small network management apparatus interface 1060 provides a communication function with the small network management apparatus.

The resource allocation unit 1070 receives allocation constrained subband information from the allocation constrained subband decision unit 1010, performs allocation of radio resources to the terminals for the remaining subbands excluding the corresponding subband, Layer 1080 of FIG.

The physical layer processing unit 1080 processes signals of the physical layer, and the RF processing unit 1190 processes signals of the RF band.

11 is a block diagram illustrating an internal configuration of a small network management apparatus according to an embodiment of the present invention.

11, a small network management apparatus according to an embodiment of the present invention includes a macro base station active terminal number management unit 1110, a small base station active terminal number management unit 1120, an assignment constrained subband adjustment unit 1130, An interference control unit 1140, a small base station interface 1150, and a macro network management device interface 1160.

The macro base station active state number management unit 1110 manages the number of active state terminals of the macro base stations in the network transmitted from the macro network management apparatus through the macro network management apparatus interface 1160.

The small base station active terminal number management unit 1120 manages the number of active terminals per small base station transmitted through the small base station interface 1150 transmitted from each small base station.

The allocation constraint subband adjuster 1130 receives information on the allocation constraint subbands of each small base station from the interference controller 1140, determines allocation constrained subbands for each small base station, and obtains information on the determined position And transmits it to the interference controller 1140.

The interference controller 1140 receives information on the number of sub-bands allocated to the small base station from each small base station through the small base station interface 1150 and stores the received information, and transmits the information to the allocation constrained sub-band adjuster 1130, Information on the allocation constrained subband position for each small base station from the allocation constrained subband adjuster 1130 and delivers the information to the corresponding small base station through the small base station interface 1150.

The small base station interface 1150 is responsible for communication with the small base station.

The macro network management device interface 1160 is responsible for communication with the macro network management device.

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

The macro base station according to an embodiment of the present invention includes an active state number management unit 1210 and a macro network management device interface 1220.

The active terminal number management unit 1210 manages the number of active terminals in the macro base station and transmits information on the number of active terminals in the macro base station to the macro network management apparatus through the macro network management apparatus interface 1220. [

The macro network management device interface 1220 performs communication with the macro network management device.

13 is a block diagram illustrating an internal configuration of a macro network management apparatus according to an embodiment of the present invention.

The macro network management apparatus according to an embodiment of the present invention includes an active state terminal number management unit 1310, a macro base station interface 1320, and a small network management apparatus interface 1330 for each macro base station.

The active state terminal number management unit 1310 according to the macro base station receives and manages information on the number of active state terminals delivered by the macro base station 1320 via the macro base station interface 1320, To the small network management apparatus via the network management apparatus interface 1330.

The macro base station interface 1320 performs communication with the macro base station.

The small network management apparatus interface 1330 performs communication with the small network management apparatus.

FIG. 14 is a flowchart illustrating an interference control procedure of a macro base station using an interference control technique through cooperation between time domain cells according to an embodiment of the present invention. Referring to FIG.

In step 1401, the macro base station receives the assignment restriction unit frame pattern list from the communication network equipment management apparatus, and proceeds to step 1503. The allocation constraint portion frame pattern indicates a subframe in which an interference-causing base station performs an allocation constraint for the purpose of mitigating interference to a neighboring interference base station. For example, the subframe for performing the allocation constraint may be indicated using a bitmap pattern. The available allocation constraint frame pattern can be determined according to specification limits or performance limitations. On the other hand, the allocation constraint frame pattern list is a set of allocation constraint frame patterns usable by the interference-causing base station. A corresponding relation between the number of allocation constraint frames and the allocation constraint subframe pattern included in the allocation constraint subframe pattern list is set so that the allocation constraint subframe pattern corresponding thereto is determined when the allocation constraint subframe number is determined.

In step 1403, the macro base station determines the number of frames in the allocation constraint part through the set process, and then proceeds to step 1505. The process of determining the number of frames of the allocation constraint portion will be described later with reference to FIG.

In step 1405, the macro base station determines an allocation constraint portion frame pattern based on the allocation constraint portion frame number and the allocation constraint portion frame pattern list, and then proceeds to Step 1505.

In step 1407, the macro base station notifies the interfering base station, i.e., the small base station, of the determined allocation constraint subframe pattern.

In step 1409, the macro base station performs radio resource allocation for the UE in the normal subframe without performing allocation of radio resources for the UE in the allocation constraint frame according to the allocation constraint frame pattern.

The operation of the small base station according to the operation of the macro base station as described with reference to FIG. 14 is as follows. In a small base station that has received an allocation constraint frame pattern from a macro base station, resources are allocated mainly to a cell edge terminal in an allocation constraint frame of a macro base station, and resources are allocated mainly to a cell center terminal in a normal subframe of a macro base station, The influence of the interference to the terminal belonging to itself is relaxed.

The allocation constraint frame number determination process may be performed by the communication network management apparatus.

FIG. 15 is a flowchart illustrating a process of determining a number of allocation constraint frames using a cooperative interference control scheme in a macro-base station according to an exemplary embodiment of the present invention.

In steps 1501a to 1501c, the macro base station acquires the number of active terminals in the sub-small base station of the macro base station transmitted by the network management apparatus, acquires the number of active terminals in the macro base station, And estimates the number of interference-protected terminals from the macro base station.

In step 1503, the macro base station counts the number of active terminals in the small base station, the number of active terminals in the macro base station, and the number of interference protection target terminals according to the cell area expansion of the small base station, obtained in steps 1501a to 1501c The number of frames of the allocation constraint section is determined.

Equation (2) shows an example in which the macro base station determines the frame number of the allocation constraint portion according to an embodiment of the present invention.

NABS: Assignment Constraint Number of Frames

G: sub-small base station set of macro base station

Naggressor: Number of active terminals in the macro base station

Nvictim [i]: Number of active terminals in macro base station sub-base station i

Nprotected [i]: number of protected target terminals in macro base station sub-base station i

Npattern: allocation constraint frame pattern cycle (unit: subframe)

Equation (2) is an example of determining the frame number of the allocation constraint unit according to an embodiment of the present invention, but the present invention is not limited thereto. For example, restriction to a predefined upper or lower limit value, quantization, etc. may be applied.

In the above-described embodiments, in an environment in which a macro base station and an authorized subscriber group (CSG) base station are overlapped and installed, in order to mitigate the interference of the CSG base station to surrounding macro base station terminals, In the case of applying the control technique, it can be extended to determine the number of frames in the allocation constraint section. In this environment, the CSG base station is an interference-causing base station, the macro base station is an interference base station, and the macro base station terminal in the vicinity of the CSG base station is an interference base station reporting target terminal . At this time, the number of allocation constraint frames may be determined by the CSG base station or by an upper network entity.

16 is a flowchart for explaining a method of estimating the number of interference-protected terminals based on a reference signal strength using an interference control technique through time-domain inter-cell cooperation according to an embodiment of the present invention.

In step 1601, the macro base station resets the reference signal received power (RSRP) measurement report condition for the small base station to the terminal in the macro base station so as to relax the measurement report condition.

In step 1603, the macro base station receives the measurement report from the terminal that satisfies the above conditions. In step 1605, the macro base station counts the number of the terminals whose measured values for the small base station in the measurement report are equal to or greater than the pre- And counts the number of the corresponding interference protection target terminals. The interference-protected terminal is a terminal expected to be handed over to a small-sized base station according to cell area expansion of a small-sized base station.

FIG. 17 is a flowchart illustrating a method of estimating the number of interference-protected terminals based on a reference signal quality using a cooperative interference control technique over a time-domain inter-cell cooperation according to an exemplary embodiment of the present invention.

In step 1701, the macro base station sets a subframe in which resource allocation is to be restricted, and then, in step 1703, the macro base station measures a reference signal quality (RSRQ) Set reporting conditions.

In step 1705, the macro base station receives the measurement report from the terminal that satisfies the measurement report condition. In step 1707, the macro base station transmits the measurement report for the small base station in the measurement report to the protection target terminal And counts the number of the corresponding protection target terminals.

FIG. 18 is a diagram for explaining an information exchange process for inter-network interference control function when applying an interference control scheme through cooperation between time domain cells according to an embodiment of the present invention.

The macro network management device transmits the assignment restriction section frame pattern list to the macro base station (step 1801). The subordinate small base station of the macro base station transmits the number of active state terminals belonging to the macro base station (step 1803). The macro base station transmits the allocation constraint portion frame pattern to the sub-small base station of the macro base station (Step 1805).

FIG. 19 is a block diagram illustrating an internal configuration of a macro base station that uses an interference control technique through time domain inter-cell cooperation according to an embodiment of the present invention.

19, a macro base station according to an embodiment of the present invention includes an allocation constraint portion frame pattern determiner 1910, a terminal measurement report manager 1930, an active terminal statistics processor 1920, an interference mitigation function controller A macro network management device interface 1950, a resource allocation unit 1960, a physical layer processing unit 1970, and an RF processing unit 1980.

The allocation constraint unit frame pattern determiner 1910 receives the allocation constraint frame number from the interference coordinator 1940 and determines the allocation constraint frame pattern and supplies the information to the resource allocation unit 1960 and the interference control unit 1940 .

The terminal measurement report management unit 1930 manages the reference signal strength and the reference signal quality received from the terminal.

The active terminal statistics processor 1920 processes the statistics of the number of active terminals in the small base station for a predetermined time interval, and transmits the statistics to the interference controller 1940.

The interference control unit 1940 determines and stores an allocation constraint subband number based on the number of other base station terminals to be protected, the number of active state terminals of the neighbor base stations, and the number of active state terminals of the macro base station, Unit 1910 of FIG.

The macro network management device interface 1950 is responsible for communication with the macro network management device.

The resource allocation unit 1960 receives the allocation constraint portion frame pattern from the allocation constraint portion frame pattern determiner 1910 and performs allocation of radio resources to the UE for the remaining subframes excluding the allocation constraint frame, Layer processing unit 1970 as shown in FIG.

The physical layer processing unit 1980 processes signals of the physical layer, and the RF processing unit 1990 processes signals of the RF band.

20 is a flowchart for explaining an allocation constrained radio resource ratio determination process of an interference-causing base station in a wireless communication system of a superposed wireless network structure according to an embodiment of the present invention.

The allocation constrained radio resource ratio determination process shown in FIG. 20 can be performed by any entity belonging to the base station or the core network, and can be applied to the embodiments of the present invention as described above with reference to the related drawings.

In steps 2001a to 2001c, the network performs acquisition of the number of active terminals in the interfered base station, acquisition of the number of active terminals in the interference-induced base station and acquisition or estimation of the number of interference-covered base stations in the interfered base station .

In step 2003, the network determines at least one of the number of active terminals in the interfering base station, the number of active terminals in the interference-causing base station, and the number of protected terminals in the interfering base station obtained or estimated in steps 2001a to 2001c Based on one, the allocation constrained radio resource ratio is determined. As described above, the network increases the allocation constrained radio resource ratio as the number of interference target terminals in the interfering base station increases, and decreases the allocation constrained radio resource ratio as the number of active terminals in the interference-causing base station or the number of active terminals in the interference base station increases . Equation (3) shows an example in which the network determines the allocation constrained radio resource ratio from the information set.

ρ: Assignment constraint radio resource ratio

G: neighboring interference of base station

N _aggressor : number of active terminals in the interference-induced base station

N _{victim [i]} : Number of active terminals in the interfering base station i

N _{protected [i]} : Number of protected terminals in the interfering base station i

Equation (3) indicates that the allocation constrained resource ratio is determined by the ratio of the number of active terminals in the interference-triggered base station to the number of terminals in the interference-based interference protection target for the number of active terminals in the interferenceed base station It is possible. For example, restriction to an upper limit value or a lower limit value previously defined in the allocation constrained resource ratio calculated in Equation (3), quantization and the like can be applied. The number of active terminals of the BS can be replaced with other values representing the traffic load status of the BS including the physical resource block usage (PRB usage).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the invention as defined by the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.

Claims (16)

A method for a base station to allocate resources in a wireless communication network,
Determining a number of subbands to be allocated in the first cell based on interference between a first cell managed by the base station and at least one second cell adjacent to the first cell;
Transmitting information on the determined number to a network management apparatus managing a plurality of base stations;
Receiving information on a start position of a subband to start allocation restriction in the first cell from the network management apparatus;
Allocating to the at least one terminal in the first cell the remainder of the total number of subbands allocable in the first cell excluding the determined number of subbands starting from the subbands according to the information on the start position, / RTI &gt;
Wherein the information about the start position is changed according to the determined number. The method according to claim 1,
The number of subbands for which the allocation is to be restricted in the first cell,
The number of active terminals in the at least one second cell received from the network management apparatus and the number of active terminals in the first cell and the number of active terminals in the at least one second cell, The number of resources, and the number of resources. 3. The method of claim 2,
Wherein the step of determining the number of subbands to be allocated in the first cell comprises:
Wherein the number of subbands to which the allocation is to be restricted is set to the number of active terminals in the first cell and the number of active terminals in the at least one second cell, Based on a ratio of the number of UEs. The method according to claim 1,
Wherein the at least one second cell represents a cell of at least one base station included in a list of peripheral base stations managed by the base station and the peripheral base station list includes at least one of a source base station according to a handover performed in association with the first cell, And the base station includes information on at least one of the base stations. A method for transmitting information for resource allocation in a wireless communication network,
A first cell of a plurality of base stations, from a first base station to a second cell which is determined based on interference between a first cell managed by the first base station and at least one second cell adjacent to the first cell, A step of receiving information on the number of inversions,
Determining a start position of a subband in which allocation is to be restricted in the first cell based on the received information;
And transmitting information on a starting position of the determined subband to the first base station,
Wherein a remaining number of subbands excluding the determined number of subbands starting from a subbands according to information on the start position among all the subbands allocable in the first cell is allocated to at least one UE in the first cell,
Wherein the information on the start position is changed according to the determined number. 6. The method of claim 5,
The number of subbands for which the allocation is to be restricted in the first cell,
The number of active terminals in the at least one second cell transmitted by the network management apparatus and the number of active terminals in the first cell and the number of active terminals in the at least one second cell, The method comprising the steps of: (a) receiving information about at least one of a plurality of resources from a plurality of sources; The method according to claim 6,
Wherein the number of subbands for which the assignment in the first cell is to be restricted is determined based on the number of active terminals in the first cell and the number of active terminals in the at least one second cell, And the number of interference-free control target terminals. 6. The method of claim 5,
Wherein the at least one second cell indicates a cell of at least one base station included in a list of peripheral base stations managed by the first base station, And information about at least one of a target base station and a target base station. A base station in a wireless communication network,
A transmitting unit,
A receiving unit,
Determining a number of subbands to be restricted in the first cell based on interference between a first cell managed by the base station and at least one second cell adjacent to the first cell, A control unit for controlling the transmitting unit to transmit to a network management apparatus managing a plurality of base stations,
When information on a start position of a subband to be allocated in the first cell is received from the network management apparatus through the receiver, information on the start position among all subbands allocable in the first cell And allocating the remainder, excluding the determined number of subbands, to at least one terminal in the first cell,
Wherein the information about the starting position is dependent on the determined number. 10. The method of claim 9,
The number of subbands for which the allocation is to be restricted in the first cell,
The number of active terminals in the at least one second cell received from the network management apparatus and the number of active terminals in the first cell and the number of active terminals in the at least one second cell, And the base station is determined based on information on at least one of the plurality of base stations. 11. The method of claim 10,
Wherein the controller is operable to determine a number of subbands to limit the assignment to the number of active terminals in the first cell and the number of active terminals in the at least one second cell, Based on a ratio of the number of interference-control target terminals. 10. The method of claim 9,
Wherein the at least one second cell represents a cell of at least one base station included in a list of peripheral base stations managed by the base station and the peripheral base station list includes at least one of a source base station according to a handover performed in association with the first cell, The base station comprising information about at least one of the base stations. A network management apparatus in a wireless communication network,
A first cell of a plurality of base stations, from a first base station to a second cell which is determined based on interference between a first cell managed by the first base station and at least one second cell adjacent to the first cell, A receiver for receiving information on the number of inverses;
A control unit for determining a start position of a subband to start allocation restriction in the first cell based on the received information;
And a transmitter for transmitting information on a start position of the determined subband to the first base station,
Wherein a remaining number of subbands excluding the determined number of subbands starting from a subbands according to information on the start position among all the subbands allocable in the first cell is allocated to at least one UE in the first cell,
Wherein the information on the start position is changed according to the determined number. 14. The method of claim 13,
The number of subbands for which the allocation is to be restricted in the first cell,
The number of active terminals in the at least one second cell transmitted by the network management apparatus and the number of active terminals in the first cell and the number of active terminals in the at least one second cell, The number of the network management apparatuses is determined based on at least one of the numbers. 15. The method of claim 14,
Wherein the number of subbands for which the assignment in the first cell is to be restricted is determined based on the number of active terminals in the first cell and the number of active terminals in the at least one second cell, And a ratio of the number of interference-free control target terminals. 14. The method of claim 13,
Wherein the at least one second cell represents a cell of a base station included in a list of peripheral base stations managed by the first base station and the list of peripheral base stations includes a source base station and a target base station Wherein the network management information includes at least one of the following:

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