KR101549503B1 - Apparatus And Method For Controlling Inter-Cell Interference Based on Coordinated Multi-Point in Macro-Femtocell Heterogeneous Network - Google Patents

Abstract

The present invention relates to an apparatus and method for inter-cell interference control based on Coordinated Multi-Point (CoMP) in a heterogeneous network, and an apparatus for inter-cell interference control according to the present invention includes: The present invention is characterized in that scheduling is performed by classifying CCU and CEU for all user terminals and priorities are compared and power control is applied to all macro cells and femtocell user terminals. .

Description

[0001] The present invention relates to an apparatus and a method for inter-cell interference control based on multipoint cooperative communication in a macro-femtocell heterogeneous network,

The present invention relates to an apparatus and method for inter-cell interference control based on Coordinated Multi-Point (CoMP) in heterogeneous networks, and more particularly, to a method and apparatus for inter-cell interference control using a macro- To an apparatus and method for inter-cell interference control based on multipoint cooperative communication in a macro-femtocell heterogeneous network to mitigate inter-cell interference with a multi-point cooperative communication base on which a smart scheme is applied.

Recently, the demand of users who want to receive high quality data service anytime and anywhere due to the spread of smart phones is rapidly increasing. Therefore, there is a need for a technique capable of supporting a high data rate not only at the cell center but also at the cell edge.

Although the cell center can simply increase the data transmission rate by supporting additional antenna ports for each cell, since the cell edge is greatly influenced by the interference from neighboring cells, the data rate is increased beyond a certain limit without intercellular cooperation It is difficult.

Also, in order to provide high-speed data service even in areas where users are concentrated, frequency reuse technology through small cells such as pico-cells or femtocells in the area of macro cells is spreading, .

Point-to-point interference control technology is currently attracting attention as a major issue in the standards and academia. In particular, the 3rd Generation Partnership Project (3GPP) calls this Coordinated Multi-Point (CoMP) Term Evolution-Advanced) Release 11 study item.

On the other hand, when a user terminal receives a signal from a base station of each cell, a general cellular system receives interference from base stations of neighboring cells together, and signals from neighboring base stations act as interference. In case of a heterogeneous net with a small cell, the transmission efficiency is lowered due to a large interference therebetween.

Accordingly, it is required to develop a technique for mitigating inter-cell interference and increase transmission efficiency through CoMP technology and to develop a technology for performance evaluation thereof.

Accordingly, it is an object of the present invention to provide an apparatus and method for inter-cell interference control based on multipoint cooperative communication in a macro-femtocell heterogeneous network for mitigating inter-cell interference and increasing transmission efficiency in a heterogeneous network .

According to an aspect of the present invention, there is provided an apparatus for inter-cell interference control based on multipoint cooperative communication in a macro-femtocell heterogeneous network, comprising: a communication unit for communication with a user terminal and another apparatus existing in a heterogeneous network; The priorities of the user terminals (CCU) located at the cell boundary having the highest priority in the cluster and the priorities of the individual user terminals A priority of a user terminal CEU located at a high cell center is calculated, a calculated priority is compared, and a scheduling is performed to apply a CoMP transmission scheme to the CEU when the priority of the CEU is higher, The scheduler performs scheduling to transmit the CCU with a general transmission scheme when the priority of the CCU is higher than that of the CCU, and the scheduling operation checks and performs all the clusters and all user terminals.

The controller of the apparatus for inter-cell interference control according to the present invention is characterized in that the CCU and the CEU are classified based on the received signal-to-interference-and-noise ratio (SINR).

According to an aspect of the present invention, there is provided an apparatus for inter-cell interference control based on multipoint cooperative communication in a macro-femtocell heterogeneous network, comprising: a communication unit for communication with a user terminal and another apparatus existing in a heterogeneous network; If the path loss value between the macro cell user terminal and the femtocell user terminal is greater than a predetermined threshold value, transmitting at maximum power, and if the path loss value between the macro cell user terminal and the femtocell user terminal is less than the preset threshold value In order to guarantee the minimum SINR of the femtocell user terminal, if it has a path loss value, it is compared with the smallest signal-to-interference-plus-noise ratio (SINR) among the connected femtocell user terminals and the target SINR of the femtocell user terminal, And a control unit for controlling the transmission power.

The control unit in the apparatus for intercellular interference control according to the present invention increases the transmission power of a femtocell when a femtocell user terminal having an SINR smaller than a target SINR exists as a result of the comparison, And controls the transmission power of the femtocell to be reduced to reduce the influence of the interference on the macro cell user terminal.

In order to guarantee a minimum SINR of the macrocell user terminal, the control unit in the apparatus for intercellular interference control according to the present invention further includes a minimum SINR among the macrocell user terminals connected to the macrocell user terminal, SINR. If the result of the comparison is that there is a macrocell user terminal having an SINR smaller than the target SINR, power control is terminated. In the opposite case, the smallest SINR among the femtocell user terminals is compared with a target SINR of the femtocell user terminal And performs an operation according to the analysis result.

According to another aspect of the present invention, there is provided a method for controlling inter-cell interference based on multipoint cooperative communication in a macro-femtocell heterogeneous network according to the present invention, A process of calculating priority; Calculating a priority of a user terminal (CCU) located in a cell boundary having the highest priority in the cluster and a priority of a user terminal (CEU) located in a cell center having a highest priority in each sector; Scheduling CoMP transmission scheme for the CEU when the priority of the CEU is higher after comparing the calculated priority; And scheduling transmission of the CCU by applying a general transmission scheme to the CCU when the priority of the CCU is higher.

Also, a method for controlling inter-cell interference according to the present invention includes: before a process of calculating a priority for all user terminals existing in one cluster; And separating the CCU and the CEU based on the received signal-to-interference noise ratio (SINR).

In addition, a method for inter-cell interference control according to the present invention is characterized in that a scheduling process is performed for all clusters and all user terminals.

According to an aspect of the present invention, there is provided a method for inter-cell interference control based on multipoint cooperative communication in a macro-femtocell heterogeneous network, comprising the steps of: confirming presence or absence of a macrocell user terminal within a femtocell coverage within a predetermined period; If the path loss value between the macrocell user terminal and the femtocell user terminal is greater than a preset threshold value, transmitting at maximum power; In order to guarantee the minimum SINR of the femtocell user terminal, if the path loss value is less than the preset threshold value, a comparison between the smallest SINR of the femtocell user terminals and the target SINR of the femtocell user terminal And controlling transmission power according to a result of the comparison and analysis.

In the method for controlling inter-cell interference according to the present invention, the step of controlling the transmission power according to the result of the comparison and analysis may include: if the femtocell user terminal having the SINR smaller than the target SINR exists, Increasing power; As a result of the comparison, when the femtocell user terminal having the SINR smaller than the target SINR does not exist, the transmission power of the femtocell is reduced to reduce the influence of the interference on the macrocell user terminal.

Also, a method for controlling inter-cell interference according to the present invention includes comparing a smallest SINR among macro cell user terminals connected to the macro cell user terminal with a target SINR of a macro cell user terminal in order to guarantee a minimum SINR of the macro cell user terminal process; And terminating the power control when a macro cell user terminal having an SINR smaller than the target SINR exists as a result of the comparison; If the result of the comparison is that there is no macrocell user terminal having a SINR smaller than the target SINR, comparing the smallest SINR among the femtocell user terminals with the target SINR of the femtocell user terminal and performing an operation according to the analysis result .

The present invention is advantageous in that the performance of a cellular system can be improved through Coordinated Multi-Point CoMP (CoMP) employing a smart improvement technique, and a gain in spectral efficiency can be obtained.

In addition, when the scheduling and power control techniques according to the present invention are applied through a comparative analysis of the performance gain according to the application of the CoMP technique when the femtocell exists in the macrocell, the performance gain of all user terminals, MUE) can be obtained. That is, when smart scheduling and power control techniques are applied together with CoMP technology, performance can be improved as compared with the prior art.

In addition, a signal-to-interference-plus-noise ratio (SINR) of a user terminal located at the edge of a macro cell is ensured through a scheduling technique. Further, by applying a power control technique There is an advantage that the SINR of the femtocell and the macrocell can be further improved.

Simulation results in heterogeneous network environment show that CoMP technology is applicable to 4G mobile communication environment where small cell exists.

1 is a diagram illustrating a heterogeneous network to which an embodiment of the present invention is applied.
2 is a diagram illustrating a typical cellular system.
3 is a diagram illustrating a CoMP CB structure according to an embodiment of the present invention.
4 is a diagram illustrating a structure of an inter-cell interference control apparatus for scheduling and power control according to a smart improvement technique according to an embodiment of the present invention.
5 is a flowchart illustrating a scheduling process according to the CoMP CS scheme according to an embodiment of the present invention.
6 is a flowchart illustrating a process for power control using a smart improvement technique according to an embodiment of the present invention.
7 is a structural diagram of a dual strip model to which the present invention is applied.
8 is a graph illustrating an SINR CDF graph for a MUE located in a macro cell when power control is applied to a CoMP-CS according to an embodiment of the present invention.
9 is a graph illustrating an SINR CDF graph for a FUE located in a femtocell when power control is applied to a CoMP-CS according to an exemplary embodiment of the present invention.
10 is a graph illustrating an SINR CDF graph for all user terminals located in a macro cell when power control is applied to a CoMP-CS according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the accompanying drawings, detailed description of well-known functions or constructions that may obscure the subject matter of the present invention will be omitted. This is to omit the unnecessary description so as to convey the key of the present invention more clearly without fading. It should be noted that the same constituent elements are denoted by the same reference numerals as possible throughout the drawings.

1 is a diagram illustrating a heterogeneous network to which an embodiment of the present invention is applied.

Referring to FIG. 1, a heterogeneous network (HetNet), which is one of LTE-Advanced networks, is based on LTE-Advanced Release 11 scenario 4.

As shown in FIG. 1, one macro cell is divided into three sectors, and three sectors adjacent to each other form a cell site as shown in (a).

At this time, one base station (eNB) and several user terminals (MUE) exist in the macro cell. Also, a femtocell exists in each macro cell, and one base station (FeNB) and a user terminal (FUE) exist in the femtocell. It is assumed that femtocells are randomly distributed within macrocells, and macrocell user terminals are randomly distributed uniformly within macrocells.

When communication is performed in such a network environment, in a general cellular system, as shown in FIG. 2, when user terminals receive a signal from each base station (eNB), they also receive interference signals from neighboring base stations.

번째 셀 내에 위치한 사용자

의 수신 신호

는 다음의 <수학식 1>과 같다.At this time

User located in the ith cell

The received signal

Is expressed by Equation (1).

는 서빙셀 기지국,

은 인접 셀 기지국을 의미하며,

은 서빙셀 내에 위치한 펨토셀 기지국을 의미한다.In Equation (1), when H _ij is a channel from an ith cell to a jth cell, W _j is a precoding matrix for a UE in a jth cell, X _ij is an i th cell j denotes a signal transmitted to a user terminal in a j-th cell. N ₀ means white noise. Also,

A serving cell base station,

Denotes a neighbor cell base station,

Denotes a femtocell base station located in a serving cell.

은 각 셀에 위치한 사용자를 의미한다. 상기 <수학식 1>에서 보는 바와 같이, 인접 셀 및 펨토셀에서 오는 신호가 간섭으로 작용함에 따라 ICI(Inter-Cell Interference)가 발생하며, 채널 용량이 제한적이다. 이에 대한 SINR(Signal to Interference plus Noise Ratio) 식은 하기 <수학식 2>와 같다.Also,

Means a user located in each cell. As shown in Equation (1), inter-cell interference (ICI) occurs due to interference of signals from neighbor cells and femtocells, and the channel capacity is limited. The SINR (Signal to Interference plus Noise Ratio) equation is shown in Equation (2) below.

In Equation (2), P _i denotes the transmission power of the i-th cell BS and N denotes the total noise power.

In the present invention, a method for controlling interference through cooperative communication between various base stations based on CoMP communication technology is proposed in order to solve the inter cell interference problem that occurs as described above.

First, all cells participating in cooperation operate as one cell in order to control inter-cell interference based on CoMP communication technology, and only antennas are distributed so that all data and channel information are processed in one device.

Therefore, it is possible to maximize the radio resource efficiency by increasing the capacity by considering the signal from the user's own base station as well as from the neighbor base station, and in particular, the transmission rate of the user terminal located at the edge of the cell can be increased.

The CoMP technique can be roughly divided into a JP (Joint Processing) scheme and a CB (Coordinated Beamforming) scheme.

First, let's look at the CoMP JP method.

에 대한 SINR 식은 하기 <수학식 3>과 같다.For CoMP JP method users

SINR < / RTI >

As shown in Equation (3), signals from other cells are also used as useful signals instead of interference signals. As a result, it can be confirmed that only the femtocell signal and noise exist as an obstructing signal. However, it has a disadvantage of wasting a plurality of resource blocks (RBs) in order to transmit the same signal.

Next, the CoMP CB scheme will be described.

In the case of the CoMP CB scheme, as shown in FIG. 3, SINR of a user terminal is measured through a received signal of a user terminal in each cell, and beamforming that maximizes the SINR is applied. This minimizes interference from neighboring cells and maximizes received signal strength.

The beamforming equation for this is shown in Equation (4).

In the present invention, the performance evaluation is preferably performed using the CoMP CB scheme having the best performance over the complexity and the feedback overhead.

Now, an apparatus for controlling inter-cell interference in order to increase the transmission efficiency by applying a scheduling and power control scheme as a method for improving the performance of the CoMP communication according to the present invention will be described with reference to FIG.

4 is a diagram illustrating a structure of an inter-cell interference control apparatus for scheduling and power control according to a smart improvement technique according to an embodiment of the present invention. The apparatus for controlling inter-cell interference according to the present invention may be one of devices capable of communicating with a user terminal, such as a base station of a heterogeneous network. The inter-cell interference control apparatus according to the present invention includes a control unit 400, a communication unit 402, , And a storage unit (404).

First, the communication unit 402 performs communication with a user terminal and another apparatus existing in the heterogeneous network.

The storage unit 404 stores data necessary for inter-cell interference control.

The controller 400 performs scheduling control and power control for each user terminal.

First, a control unit 400 for performing scheduling, which is one of the methods for improving CoMP performance, will be described. In the embodiment of the present invention, the spectrum efficiency of the entire user, especially the user edge located at the edge of the cell can be improved, and the CS (Coordinated Scheduling) technique is applied to the user terminal as a scheduling technique in order to provide high quality service to the user terminal .

This CS scheme is a scheme in which all UEs existing in one cell are classified by CCU and CEU and compared with each other in order of priority.

의 우선순위

와 각 섹터 별로 우선순위가 가장 높은 CCU인

,

,

에 대한 우선순위

,

,

를 계산하고, 계산된 우선순위를 비교한다. 비교 결과 만약, 사용자

의 우선순위가 더 높은 경우,

에 대해 CoMP 전송 방식을 적용하도록 스케줄링 하고, 사용자

,

,

의 우선순위가 더 높은 경우

,

,

에 대해 일반적인 전송 방식을 적용하여 전송하도록 스케줄링 한다. 이와 같은 스케줄링 과정은 모든 클러스터 및 모든 사용자 단말에 대해 체크하여 수행한다.The controller 400 distinguishes between a user terminal (CCU) located at the cell center and a user terminal (CEU) located at the cell boundary based on the received SINR. Thereafter, the controller 400 selects the user terminal RB (r) and the cluster (c), and calculates the priority for all the user terminals in the selected cluster (cluster). Thereafter, the control unit 400 determines whether the CEU having the highest priority in the cluster cell

Priority of

And the highest priority CCU for each sector

,

,

Priority for

,

,

And compares the calculated priorities. As a result of comparison,

Is higher,

The CoMP transmission scheme is applied to the user,

,

,

If your priority is higher

,

,

To be transmitted according to a general transmission scheme. Such a scheduling process is performed by checking all the clusters and all the user terminals.

Next, power control of the controller 400, which is one of the ways to improve the CoMP performance, will be described. In the conventional CoMP communication scheme, it is possible to mitigate the interference from the adjacent cell, but it is affected by the interference from the femtocell. In order to solve this problem, in the present invention, power control is applied to all user terminals of a macrocell and a femtocell, thereby increasing spectral efficiency as interference from a femtocell is reduced. Finally, a reliable service is provided to a user terminal .

The control unit 400 periodically checks whether there is a macro cell user terminal within the femtocell coverage.

As a result, if the path loss value between the macro cell user and the femtocell is larger than the threshold value, the controller 400 transmits the femtocell at the maximum power. However, if the path loss value is less than a predetermined level, the controller 400 compares the smallest SINR among the femtocell user terminals connected to the user terminal with the target SINR of the femtocell user terminal in order to guarantee the minimum SINR of the femtocell user terminal.

If the femtocell user terminal having the SINR smaller than the target SINR exists, the control unit 400 increases the transmission power of the femtocell and vice versa. Thereby reducing the influence of the interference on the macro cell user terminal.

In addition, the controller 400 compares the smallest SINR among the macro cell user terminals connected to the macro cell user terminal with the target SINR of the macro cell user terminal in order to guarantee the minimum SINR of the macro cell user terminal. If the result of the comparison is that there is a macrocell user terminal having a SINR smaller than the target SINR, the operation ends according to the analysis result by comparing and analyzing the smallest SINR among the femtocell user terminals and the target SINR of the femtocell user terminal do.

Now, a process of performing scheduling and power control in an apparatus for inter-cell interference control configured as shown in FIG. 4 according to the present invention will be described with reference to the flowcharts of FIGS. 5 and 6. FIG.

First, a scheduling process according to the CoMP CS scheme according to an embodiment of the present invention will be described with reference to FIG. 5 is a flowchart illustrating a scheduling process according to the CoMP CS scheme according to an embodiment of the present invention.

5, a cell center user (hereinafter, referred to as a CCU) located at a cell center and a cell edge user (CEU) located at a cell boundary based on the received SINR, ; Hereinafter referred to as CEU).

And selects the user terminal RB (r) and the cluster (c) (S502 to S503).

And calculates a priority for all user terminals in the selected cluster (S503)

의 우선순위

와 각 섹터 별로 우선순위가 가장 높은 CCU인

,

,

에 대한 우선순위

,

,

를 계산하고, 계산된 우선순위를 비교한다.(S504 ~ S505)Thereafter, the highest priority CEU in the cluster cell

Priority of

And the highest priority CCU for each sector

,

,

Priority for

,

,

And compares the calculated priorities (S504 to S505).

의 우선순위가 더 높은 경우,

에 대해 CoMP 전송 방식을 적용하도록 스케줄링 한다.(S506)If the user

Is higher,

(S506)

,

,

의 우선순위가 더 높은 경우

,

,

에 대해 일반적인 전송 방식을 적용하여 전송하도록 스케줄링 한다.(S507)user

,

,

If your priority is higher

,

,

(S507). [0064]

The above steps S503 to S507 are performed to check all the clusters and all the user terminals (S508, S509, S510, S512)

Referring now to FIG. 6, a process for power control according to an embodiment of the present invention will be described with reference to a smart improvement technique. 6 is a flowchart illustrating a process for power control using a smart improvement technique according to an embodiment of the present invention.

Referring to FIG. 6, the femtocell periodically checks whether a macrocell user terminal exists within a femtocell coverage period (S600)

는 매크로셀 사용자 단말의 상향링크 전송 전력,

는 매크로셀 사용자 단말에 대한 펨토셀에서의 수신 전력이며,

는 매크로셀 사용자와 펨토셀 사이의 거리를 결정하기 위한 문턱값으로써 dB 단위로 표현된다.Thereafter, if the path loss value between the macrocell user and the femtocell is greater than the threshold value, the femtocell transmits at maximum power (S602). In this case,

Is the uplink transmission power of the macrocell user terminal,

Is the received power in the femtocell for the macrocell user terminal,

Is a threshold for determining the distance between the macrocell user and the femtocell, expressed in units of dB.

와 펨토셀 사용자 단말의

과 비교 분석한다.(S603 ~ S604) S604단계에서

은 펨토셀 사용자 단말의 최소 SINR이다.

은 각각 펨토셀 사용자 단말의 목표 SINR이다.However, if the femtocell has a path loss value less than a predetermined level, the femtocell is the smallest SINR among the femtocell user terminals connected to the femtocell user terminal in order to guarantee the minimum SINR of the femtocell user terminal

And the femtocell user terminal

(S603 to S604). In step S604,

Is the minimum SINR of the femtocell user terminal.

Is the target SINR of the femtocell user terminal, respectively.

와

는 각각 펨토셀의 최대 및 최소 송신 전력이며,

는 측정 SINR과 목표 SINR에 따라 펨토셀 송신 전력의 크기를 조절할 수 있는 파라미터이다.In step S604, if the femtocell user terminal having the SINR smaller than the target SINR exists, the transmission power of the femtocell is increased (S605). If the femtocell user terminal has the SINR smaller than the target SINR, the transmission power of the femtocell is decreased Thereby reducing the influence of the interference on the macro cell user terminal (S606). In this case, in steps S605 and S606

Wow

Are the maximum and minimum transmission power of the femtocell, respectively,

Is a parameter capable of adjusting the size of the femtocell transmission power according to the measured SINR and the target SINR.

와 매크로셀 사용자 단말의

과 비교한다.(S608) 이때, S608단계에서

는 펨토셀 반경 이내에 존재하는 매크로셀 사용자 단말의 최소 SINR이고,

은 매크로셀 사용자 단말의 목표 SINR이다.In order to guarantee the minimum SINR of the macrocell user terminal, the smallest SINR among the macrocell user terminals connected to the macrocell user terminal

And the macro cell user terminal

(S608). At this time, in step S608

Is the minimum SINR of the user terminal of the macrocell existing within the radius of the femtocell,

Is the target SINR of the macrocell user terminal.

와 펨토셀 사용자 단말의

과 비교 분석하여 분석 결과에 따른 동작을 수행한다.If it is determined in step S608 that there is a macro cell user terminal having an SINR smaller than the target SINR, the process ends in step S604, and if it is the smallest SINR among the femtocell user terminals

And the femtocell user terminal

And performs the operation according to the analysis result.

As described above, according to the present invention, the performance change according to the CoMP technique applied in the macro-femtocell heterogeneous network and the performance gain when the scheduling and power control according to the present invention are applied to CoMP are shown in graphs of FIGS. 8 to 10 You will be able to see.

At this time, the simulation environment conforms to the 3GPP LTE-A standard. A system level simulator is constructed based on the parameters for macrocells and femtocells as shown in Table 1, Table 2, and Table 3 below. Further, a simulation is performed on the assumption that one femtocell exists in each macro cell.

는 아파트 외벽 통과시의 투과 손실로, 10 dB 또는 20 dB로 정의한다.

는 아파트를 분리하는 벽 통과시의 투과 손실이며, 그 값은 5 dB로 정의한다.

는 아파트 내부의 거리로서, 내벽으로 인한 투과 손실 계산 시에 사용되는 값이다.Also, a dual strip model is used as shown in FIG. 7, and the path loss model of Table 4 is applied. At this time,

Is defined as 10 dB or 20 dB in terms of transmission loss when passing through the exterior wall of the apartment.

Is the transmission loss when passing through a wall separating an apartment, and its value is defined as 5 dB.

Is a distance inside the apartment and is a value used in calculation of the transmission loss due to the inner wall.

In addition, the simulation procedure is as follows. First, a heterogeneous network system structure is constructed according to parameters, and a position of a base station and a user terminal is set, and then CoMP and smart improvement techniques are selected. Thereafter, the receiver receives the signal transmitted from the base station and passed through the channel, thereby measuring the received power and the interference power. The SINR is calculated using this value, and its performance is analyzed through a CDF (Cumulative Distribution Function) graph.

Parameter Value Cellular Layout Hexagonal grid,
7 cell sites, 3 sectors per site Cell Coverage Radius 189m (ISD = 500m) Carrier Frequency 2 GHz Channel Bandwidth 10 MHz Shadowing standard deviation 8 dB Auto-correlation
distance of Shadowing 50 m Shadowing correlation Between cells Between sectors 1.0 Antenna pattern (horizontal) eNB: 3 sectorized
UE: Omni BS antenna gain
after cable loss 14 dBi BS noise figure 5 dB Number of eNB antenna 1 Tx UE Antenna gain 0 dBi UE Noise Figure 7 dB Number of UE antennas 1 Rx Total BS TX power 46 dBm UE distribution dropped with uniform density within the indoors / outdoors macro coverage area Minimum distance
between eNB and UE > = 35 m

Parameter Value Carrier Frequency 2 GHz Channel Bandwidth 10 MHz Cell Coverage 10 m Min separation UE to femto 3 m Number of Tx antennas at femto One Femto antenna pattern omni Femto antenna gain 5 dBi FeNB Min / Max Tx power -10/20 dBm Maximum number of FUE per femto One

Parameter Value K (number of cells per column) 4 N (number of cells per row) 10 M (number of blocks per sector) One L (number of floors per block) 6 R (deployment ratio) 0.1 P (activation ratio) One Probability of macro UE being indoors 35%

Cases Path Loss (dB) UE to Macro eNB UE is outside

,

in m

,

in m UE is inside an apt

,

in m UE to Femto eNB Dual-strip model: UE is inside the same apt stripe as femto

and

are in m

is the number of penetrated floors

This is a great place to stay.
In case of a single-floor apt, the last term is not needed Dual-strip model: UE is outside the apt stripe

and

are in m

This is a great place to stay.

Table 1 shows the macrocell simulation parameters based on the 3GPP LTE-A 10MHz bandwidth for the simulation, Table 2 shows the femtocell simulation parameters for the simulation, Shows the femtocell modeling parameters for the simulation, and Table 4 shows the path loss model for the simulation.

CDF graphs according to SINR when scheduling and power control are applied to multi-point collaborative communication based on the macro-femtocell heterogeneous network environment according to the present invention are shown in FIGS. 8 to 10. This allows you to see the performance gains of MUE and FUE.

8 to 10 show CDF graphs according to SINR when power control is applied to CoMP-CS. FIG. 8 shows an SINR for a MUE located in a macro cell when cooperation between macro cells is performed, and FIG. 9 shows an SINR for a FUE located in a femtocell. 10 shows the SINR for all user terminals located in the macrocell.

As shown in the performance result graph shown in FIGS. 8 to 10, it can be seen that both the MUE and the FUE as well as the performance of the entire user terminals are improved through the power control. In addition, it shows the greatest performance gain in combination with CoMP-CS and power control, and it has a great influence on the performance gain of MUE.

In addition, the outage probability for the MUE and FUE can be expressed as shown in Table 5 below.

Non-CoMP-Non-PC Non-CoMP-PC CoMP-CS-PC MUE (SINR 6dB standard) 76.2% 72.5% 54.2% FUE (based on SINR 24dB) 36.7% 30.8% 28.9%

Table 5 above compares the Outage Probability for the SINR performance. The outage probability was measured based on 6 dB for MUE and 24 dB for FUE. In the case of MUE, Non-CoMP-Non-CoMP-PC is 3.7% higher than that of Non-CoMP-Non-PC when only power control is applied. When CoMP-CS- 22% higher than CoMP-Non-PC. Non-CoMP-Non-PC is improved by 5.9% compared to non-CoMP-Non-PC when FEA is applied to non-CoMP-PC combined with power control. It is 7.8% higher than PC.

It can be seen that the performance gain of the macro-femtocell network is high when the CoMP and the power control are used for all user terminals, and the performance gain of the MUE is greatly increased.

The method for inter-cell interference control based on multi-point cooperative communication in a macro-femtocell heterogeneous network according to the present invention can be implemented in the form of software readable by various computer means and recorded in a computer-readable recording medium. Here, the recording medium may include program commands, data files, data structures, and the like, alone or in combination. Program instructions to be recorded on a recording medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. For example, the recording medium may be an optical recording medium such as a magnetic medium such as a hard disk, a floppy disk and a magnetic tape, a compact disk read only memory (CD-ROM), a digital video disk (DVD) Includes a hardware device that is specially configured to store and execute program instructions such as a magneto-optical medium such as a floppy disk and a ROM, a random access memory (RAM), a flash memory, do. Examples of program instructions may include machine language code such as those generated by a compiler, as well as high-level language code that may be executed by a computer using an interpreter or the like. Such hardware devices may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be apparent to those skilled in the art. Furthermore, although specific terms are used in this specification and the drawings, they are used in a generic sense only to facilitate the description of the invention and to facilitate understanding of the invention, and are not intended to limit the scope of the invention.

Further, a computer program (also known as a program, software, software application, script or code) that is embedded in the apparatus according to the present invention and which implements the method according to the present invention includes a compiled or interpreted language, a priori or procedural language , And may be deployed in any form including standalone programs or modules, components, subroutines, or other units suitable for use in a computer environment. A computer program does not necessarily correspond to a file in the file system. The program may be stored in a single file provided to the requested program, or in multiple interactive files (e.g., a file storing one or more modules, subprograms, or portions of code) (E.g., one or more scripts stored in a markup language document). A computer program may be deployed to run on multiple computers or on one computer, located on a single site or distributed across multiple sites and interconnected by a communications network.

Further, in describing a method for inter-cell interference control based on multipoint cooperative communication in a macro-femtocell heterogeneous network according to the present invention, operations are depicted in the drawings in a particular order, It should be understood that such operations should be performed in a specific order or in a sequential order, or that all illustrated operations should be performed. In certain cases, multitasking and parallel processing may be advantageous. Also, the separation of the various system components of the above-described embodiments should not be understood as requiring such separation in all embodiments, and the described program components and systems will generally be integrated together into a single software product or packaged into multiple software products It should be understood.

The next generation mobile communication core technology obtained through the present invention is expected to contribute not only to enhancement of mobile communication performance but also to export of terminal parts and network construction. Specifically, it will contribute to securing superiority in standardization competition and leading the next generation mobile communication market. It will improve technology self-reliance and price competitiveness of domestic mobile communication industry through transfer of intellectual property rights such as patents related to next generation mobile communication, In addition to reducing the cost of mobile communication industry due to cross-licensing, it is anticipated to reduce the royalty payment and import substitution effect by securing core technology of next generation mobile communication.

In addition, successful application of the results obtained through the present invention to B4G and 5G systems will be a preemptive technology in cellular environments. This technology guarantees the cell boundary performance of B4G and 5G mobile communication systems, which can enhance mobility. In addition, large-capacity high-speed data transmission can improve spectrum efficiency, expand service areas, and reduce network construction costs. In this way, the key technologies of this study are expected to bring about academic ripple effect and secure prior art for national research and development.

400: control unit 402: communication unit 404:

Claims (11)

delete delete A communication unit for communication with a user terminal and another device existing in the heterogeneous network;
If the path loss value between the macro cell user terminal and the femtocell user terminal is greater than a predetermined threshold value, transmitting at maximum power, and if the path loss value between the macro cell user terminal and the femtocell user terminal is less than the preset threshold value In order to guarantee the minimum SINR of the femtocell user terminal, if it has a path loss value, it is compared with the smallest signal-to-interference-plus-noise ratio (SINR) among the connected femtocell user terminals and the target SINR of the femtocell user terminal, Therefore, the control unit controls the transmission power;
Wherein the inter-cell interference control is based on multipoint cooperative communication in a macro-femtocell heterogeneous network. The apparatus of claim 3,
As a result of the comparison, if the femtocell user terminal having the SINR smaller than the target SINR exists, the transmission power of the femtocell is increased, and in the opposite case, the transmission power of the femtocell is decreased to reduce the influence of interference Wherein the inter-cell interference control is based on multipoint cooperative communication in a macro-femtocell heterogeneous network. The apparatus of claim 3,
In order to guarantee the minimum SINR of the macro cell user terminal, the macro cell user terminal compares the smallest SINR among the macro cell user terminals connected to the macro cell user terminal with the target SINR of the macro cell user terminal, And if the femtocell user terminal is present, the power control is terminated. In the opposite case, the smallest SINR of the femtocell user terminal is compared with the target SINR of the femtocell user terminal, and the operation is performed according to the analysis result. For inter-cell interference control on a multipoint cooperative communication basis. delete delete delete Checking whether there is a macro cell user terminal within a femtocell coverage every predetermined period;
If the path loss value between the macrocell user terminal and the femtocell user terminal is greater than a preset threshold value, transmitting at maximum power;
In order to guarantee the minimum SINR of the femtocell user terminal, if the path loss value is less than the preset threshold value, a comparison between the smallest SINR of the femtocell user terminals and the target SINR of the femtocell user terminal And controlling transmission power according to a result of the comparison and analysis;
Wherein the inter-cell interference control is based on a multipoint cooperative communication in a macro-femtocell heterogeneous network. The method as claimed in claim 9, wherein the step of controlling the transmission power according to the result of the comparison and /
If the femtocell user terminal having the SINR smaller than the target SINR exists, increasing the transmission power of the femtocell;
If the femtocell user terminal having the SINR smaller than the target SINR does not exist, reducing the transmission power of the femtocell to reduce the influence of the interference on the macrocell user terminal;
Wherein the inter-cell interference control is based on a multipoint cooperative communication in a macro-femtocell heterogeneous network. 10. The method of claim 9,
Comparing the smallest SINR among the macro cell user terminals connected to the macro cell user terminal with the target SINR of the macro cell user terminal in order to guarantee the minimum SINR of the macro cell user terminal;
And terminating the power control when a macro cell user terminal having an SINR smaller than the target SINR exists as a result of the comparison;
Comparing the smallest SINR among the femtocell user terminals with a target SINR of the femtocell user terminal and performing an operation according to an analysis result if a macrocell user terminal having an SINR smaller than the target SINR does not exist;
The method comprising the steps of: receiving a macro-femtocell heterogeneous network;

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