KR20140003181A - Method and apparatus for grouping femtocell base stations - Google Patents

Abstract

Provided are a method and an apparatus for determining cooperative units of femtocell base stations and terminal connection. The method whereof calculates an average transmission rate of a terminal by using the information about the communication status of the terminal and determines the cooperative unit and the terminal connection based on the average transmission rate thereof. The determined cooperative unit and terminal connection are transmitted to the femtocell base station and the terminal. The terminal connects to the femtocell base station depending on the cooperative unit. [Reference numerals] (610) Terminal; (620) Femtocell base station; (630) Representative base station; (640) Generating a femtocell access request message; (645,650) Femtocell access request message; (660) Calculating the average transmission rate of the terminal; (670) Determining a cooperative unit and terminal connection; (680) Generating a femtocell access response message; (685,690) Femtocell access response message

Description

METHOD AND APPARATUS FOR GROUP FEMTOCELL BASE STATIONS [0002]

The following embodiments are directed to a method and apparatus for cooperative unit determination of femtocell base stations, and more particularly to a method for determining a cooperative unit for femtocell base stations using cooperative communication in a heterogeneous cellular system, Lt; / RTI >

Terminal access may mean that the terminal connects to a particular base station. One of the techniques of terminal connection is a method in which a terminal makes a wireless connection to a nearest base station having a maximum reception signal among a plurality of base stations.

The UE calculates an average signal-to-interference ratio (SIR) and an expected transmission rate for each of the base stations by using a reference signal from the base stations. The terminal transmits the calculated expected transmission rate to each of the base stations, and the base station determines whether to connect the terminal to the base station in consideration of the total number and load of the terminals connected to the base station.

A heterogeneous cellular network system is a cellular network system including a macrocell and a femtocell. The heterogeneous cellular network system can improve the communication performance of a terminal by installing a femtocell in a shadow area and an indoor area in a macro cell.

In a heterogeneous cellular network system, when base stations in each cell of a system communicate with terminals in its own cell while maintaining a frequency reuse of '1' in the same time and frequency band without regard to other cells, As the UE is located close to the cell boundary, it experiences degradation in performance due to interference from other cells.

Multi-cell Coordinated Multiple Processing (CoMP) is one of techniques for overcoming the above deterioration in performance. The base stations forming the cooperating unit can cooperate to improve the transmission rate of the heterogeneous cellular system.

One embodiment can provide a method and a method for setting up a cooperative unit and a terminal connection of a femtocell base station in consideration of load of a macro cell and position of a terminal.

One embodiment of the present invention can provide a method and a method for setting up a cooperative unit and a terminal connection of a femtocell base station based on an expected average transmission rate of a terminal considering macrocell base station and terminal conditions without cooperation with a macrocell base station.

In one aspect, a method is provided for an electronic device to determine a cooperative unit of femtocell base stations in a femtocell cluster, the method comprising: receiving information on a communication state of the terminal; Determining a cooperative unit based on the average transmission rate, and transmitting information on the determined cooperative unit. The cooperative unit of the femtocell base stations may be provided.

The cooperating unit may be determined for each of a plurality of layers of a subchannel.

The information on the communication state may include at least one of information about a traffic state of a macro cell, signal-to-noise ratio information for each of one or more femtocell base stations close to the terminal, and information about the terminal.

The information on the traffic state of the macrocell may include at least one of the number of antennas of the macrocell base station of the macrocell, the average rate of transmission of the macrocell, and the number of terminals of the macrocell.

The step of calculating the average transmission rate of the UE and the step of determining the cooperating unit may be repeatedly performed.

The result of the calculation of the average transmission rate and the result of the determination of the cooperation unit can be fed back to each other.

The cooperating unit may be calculated based on a greedy algorithm.

The cooperative unit may be determined by maximizing proportional fairness between terminals in the femtocell cluster.

Information on the communication state of the UE can be transmitted from each of the femtocell base stations.

The determined cooperative unit information may be transmitted to each of the femtocell base stations.

The information on the communication state of the terminal may reflect the load of the macro cell and the location of the terminal.

According to another aspect of the present invention, there is provided an electronic device for determining a cooperative unit of femtocell base stations in a femtocell cluster, comprising: a networking unit for receiving information on a communication state of a terminal and transmitting information on the determined cooperative unit; And a processor for calculating an average transmission rate of the terminal using the information on the average transmission rate and determining the cooperation unit based on the average transmission rate.

There is provided a method and apparatus for setting up a cooperative unit and a terminal connection of a femtocell base station based on an expected average transmission rate of a terminal considering macrocell base station and terminal conditions without cooperation with a macro cell base station.

Effective data off-loading can be provided by determining cooperating units. The established cooperation unit and terminal connection can improve not only the performance of the terminal but also the performance of the heterogeneous cellular network system.

1 illustrates a heterogeneous cellular network system in accordance with one embodiment.
2 shows a femtocell cluster according to an embodiment.
3 shows a cooperative unit according to an example.
4 is a block diagram of a UE according to an embodiment of the present invention.
5 is a block diagram of a femtocell base station according to an embodiment of the present invention.
6 is a signal flow diagram illustrating a method of operating a femtocell cluster according to an embodiment.

In the following, embodiments will be described in detail with reference to the accompanying drawings. Like reference symbols in the drawings denote like elements.

In the following, 'proximity' may mean that two entities are located within a certain distance, which means that the entities are located within a distance suitable for communicating with each other.

A cooperating unit may mean a set of base stations, i.e., base stations, that cooperatively transmit cooperative transmissions. For example, when it is assumed that the channel information fed back from the terminal is perfect, interference may not occur within the cooperation unit. Zero Forcing (ZF) can be used as a cooperative transmission technique.

The terminal connection may mean that the terminal determines which base station or cooperating unit to receive the data. That is, it may mean to determine a base station or cooperating unit with which the terminal communicates. If there are several base stations or cooperating units around the terminal, one of the plurality of base stations or cooperating units may be selected as a base station or cooperating unit to communicate with the terminal. The above selection process may be an operation in which overhead is added to the heterogeneous cellular network system, the base station or the terminal. Thus, once the base station or cooperating unit to communicate is determined, a certain amount of time is generally required until the base station or cooperating unit to communicate is determined again. Accordingly, a method of determining which base station or cooperating unit communicates with a terminal to receive the service can serve as an important factor for determining the transmission capacity of the heterogeneous cellular network system.

In determining cooperating units in a heterogeneous cellular network system, the following issues may be considered.

1) In the heterogeneous cellular network system, the femtocell base stations and the femtocell terminals are irregularly arranged. Therefore, the performance of the heterogeneous cellular network system can be improved by determining the cooperative unit in consideration of the location of the femtocell terminal.

2) The transmission power of the femtocell and the number of terminals are relatively smaller than the transmission power of the macrocell and the number of terminals. Therefore, in determining the cooperative unit, the relative traffic situation between the macrocell and the femtocell needs to be considered.

For efficient data offloading, a cooperative unit needs to be determined in consideration of the load of the macrocell and the terminals, and the terminal connection considering the cooperative unit needs to be established.

1 illustrates a heterogeneous cellular network system in accordance with one embodiment.

The heterogeneous cellular network system 100 may include a macro cell base station 110 and one or more femtocell clusters.

In FIG. 1, a first femtocell cluster 121, a second femtocell cluster 122, a third femtocell cluster 123, and a fourth femtocell cluster 124 are shown as one or more femtocell clusters.

One or more femtocell clusters are distributed in the area 111 of the macrocell of the macrocell base station 110.

The femtocell cluster may be a group of femtocell base stations in which one or more femtocell base stations are clustered. Femtocell clusters can be formed in areas with high demand for wireless data such as offices, apartments, condominiums and airports.

2 shows a femtocell cluster according to an embodiment.

The femtocell cluster 200 may correspond to one of the first femtocell cluster 121, the second femtocell cluster 122, the third femtocell cluster 123 and the fourth femtocell cluster 124 described above with reference to FIG. 1 .

In the femtocell cluster 200, there may be one or more femtocell base stations and one or more terminals. The terminals may be femtocell terminals communicating with the femtocell base stations.

i may be an index of a femtocell cluster within the heterogeneous cellular network system 100. [ That is, i may indicate the femtocell cluster 200 among the one or more femtocell clusters of the heterogeneous cellular network system 100.

In Figure 2, the i-th femtocell cluster 5 in the femtocell base station (210-1, 210-2, 210-3, 210-4 and 210-5) and eight terminals (220-1, 220-2, 220-3, 220-4, 220-5, 220-6, 220-7, and 220-8).

The area 201 of the femtocell cluster 200 is configured such that the terminal communicates with at least one of the femtocell base stations 210-1, 210-2, 210-3, 210-4, and 210-5 in the femtocell cluster 200 Can be shown.

2, the two UEs 220-7 and 220-8 communicate with the femtocell base stations 210-1, 210-2, 210-3, 210-4 and 210-5 in the femtocell cluster 200 It was shown to be in an area that could not be done. Thus, the two terminals 220-7 and 220-8 can communicate with the macro cell base station 110. [

X _i ^f may be a set of locations of femtocell base stations. x ^f _{i , j} may be the location of the j th femtocell base station of the i th femtocell cluster. The positions of the five femtocell base stations 210-1, 210-2, 210-3, 210-4 and 210-5 in FIG. 2 are denoted as x ^f _{i , 0} , x ^f _{i , 1} , x ^f _{i ,} , x ^f _{i , 3,} and x ^f _{i , 4} .

U _i may be a set of locations of terminals located in the vicinity of the i-th femtocell cluster. and u _j may be the location of the jth UE among the UEs located in the vicinity of the i th femtocell cluster. Here, in the vicinity of the i-th femtocell cluster terminal may be in either the inside of the i region 201 of the second femtocell cluster, the area 201 and the adjacent terminals. Figure 7 position of the terminals (220-1, 220-2, 220-3, 220-4, 220-5, 220-6, 220-7 and 220-8) are in the second u _0, u _1, respectively, u ₂ , u ₃ , u ₄ , u ₅ , u _6, and u ₇ .

3 shows a cooperative unit according to an example.

A subchannel that can be used in the heterogeneous cellular network system 100 may be divided into a plurality of layers. In Fig. 3, the subchannel is divided into three layers: a first layer, a second layer, and a third layer.

k is an integer equal to or greater than 1 and can represent the index of the layer.

는 i 번째 펨토셀 클러스터의 k 번째 레이어를 위해 결정된 협력 단위에 대한 파티션 집합일 수 있다.

의 원소는 k 번째 레이어를 위한 특정한 협력 단위를 이루는 펨토셀 기지국들의 위치들의 집합일 수 있다.

May be a partition set for the cooperative unit determined for the kth layer of the ith femtocell cluster.

May be a set of locations of femtocell base stations that form a particular cooperative unit for the kth layer.

는 i 번째 펨토셀 클러스터의 k 번째 레이어를 위해 결정된 단말 접속에 대한 파티션 집합일 수 있다.

의 원소는 k 번째 레이어를 위한 특정한 협력 단위에 접속하는 단말들의 위치들의 집합일 수 있다. 즉, 협력 단위에 기반하여 단말 접속이 결정될 수 있다.

May be a partition set for the terminal connection determined for the k- th layer of the i- th femtocell cluster.

May be a set of locations of terminals that connect to a specific cooperative unit for the kth layer. That is, the terminal connection can be determined based on the cooperation unit.

및

의 묶음 또는 집합은

로 표시될 수 있다. 즉,

는 하기의 수학식 1에 따라 정의될 수 있다.

And

A bundle or set of

. ≪ / RTI > In other words,

Can be defined according to the following equation (1).

의 원소들 중 마지막 원소인 집합은 매크로셀 기지국으로 접속하는 단말들의 위치들의 집합일 수 있다.

의 원소들 중 마지막 원소를 제외한 나머지 원소는 각각

의 원소들 중 같은 순서의 원소에 대응할 수 있다. 예컨대,

의 원소들 중 n 번째 집합에 대응하는 단말들은,

의 원소들 중 n 번째 원소가 나타내는 협력 그룹에 접속할 수 있다. n은 1 이상 N 이하의 정수일 수 있다. N은

의 원소들의 개수일 수 있다.

May be a set of positions of terminals connected to a macro cell base station.

The remaining elements except for the last element are

Of the elements in the same order. for example,

The terminals corresponding to the n < th >

To the cooperative group indicated by the n- th element among the elements of < RTI ID = 0.0 > n may be an integer of 1 or more and N or less. N is

Lt; / RTI >

The terminals corresponding to the first set may mean terminals having one of the positions included in the first set. The cooperative group represented by the first set may refer to a group of femtocell base stations constituting the cooperative unit, having a position of one of the positions included in the first set.

및

에서 나타난 것과 같이, 하나 이상의 펨토셀 기지국들 및 하나 이상의 단말들은 복수 개의 레이어들에 대해 다양한 협력 단위 및 단말 접속 형태를 구성할 수 있다. 따라서, 어느 한 레이어에서 협력 단위들 간의 경계에 위치한 경계 단말은 다른 레이어에서는 하나의 협력 단위의 내부에 위치한 내부 단말일 수 있다. 따라서, 단말들 각각의 성능이 향상될 수 있다.
3,

And

, One or more femtocell base stations and one or more terminals may configure various cooperation units and terminal connection forms for a plurality of layers. Accordingly, a border terminal located at a boundary between cooperating units in one layer may be an internal terminal located inside one cooperating unit in another layer. Therefore, the performance of each of the terminals can be improved.

4 is a block diagram of a UE according to an embodiment of the present invention.

The terminal 400 may include a processing unit 410, a storage unit 420, and a networking unit 430. The terminal 400 may be a macro cell terminal or a femtocell terminal. That is, the terminal 400 can access the macro cell base station 110 or the femtocell base station for communication.

The processing unit 410 may be a general processor, a communication processor, or a system chip. The processing unit 410 may process a task necessary for the operation of the terminal 400. [

The networking unit 430 may be a network chip or an antenna. The networking unit 430 may be an antenna for wireless communication. The networking unit 430 can process a job required for data transmission / reception of the terminal 400, and can transmit or receive a signal for data transmission / reception. The processing unit 410 can transmit and receive data necessary for the operation of the terminal 400 by controlling the networking unit 430. [

The processing unit 410 may perform the following operations.

The processing unit 410 can estimate information on the traffic status of the macro cell that the terminal 400 currently accesses. Here, the information on the traffic state of the macrocell may include at least one of the number of antennas of the macrocell base station 110 of the macrocell, the average rate of transmission of the macrocell, and the number of terminals of the macrocell.

The processing unit 410 may store information on the traffic state of the estimated macrocell in the storage unit 420.

The processing unit 410 may search for one or more adjacent femtocell base stations. The processing unit 410 can search for one or more femtocell base stations close to the terminal 400 by using a reference signal of the femtocell base station in each femtocell cluster. The processing unit 410 may generate a list of one or more discovered femtocell base stations. The processing unit 410 may store the generated list in the storage unit 420.

The processing unit 410 may measure a signal-to-noise ratio (SNR) between each of the one or more femtocell base stations and the terminal 400 searched using the reference signal. The processing unit 410 may store the measured SNR in the storage unit 420.

The processing unit 410 may generate information on the terminal 400. [ The information about the terminal 400 may include at least one of the number of antennas of the terminal 400 and the minimum rate of the terminal 400.

The processing unit 410 may generate a femtocell connection request message. The femtocell access request message is a message for requesting connection to the femtocell, and may include information on the communication state of the terminal 400. [ The femtocell access request message may include one or more of the following information: 1) information on the traffic state of the macrocell, 2) SNR information on each of one or more femtocell base stations adjacent thereto, and 3) information on the terminal. That is, the information on the communication state of the terminal 400 may reflect the load of the macrocell and the location of the terminal 400. [

The processing unit 410 may control the networking unit 430 to transmit the femtocell access request message to the femtocell base station. The networking unit 420 may transmit the femtocell access request message to the femtocell base station.

5 is a block diagram of a femtocell base station according to an embodiment of the present invention.

Each of the one or more base stations described above with reference to FIG. 2 may be a femtocell base station 500.

The femtocell base station 500 may include a processing unit 510, a wireless networking unit 520, and a wired networking unit 530.

The processing unit 510 may be a general purpose processor, a communications processor, a system chip, or a server. The processing unit 510 may process a task required for the operation of the femtocell base station 500. [

The wireless networking unit 520 may be a network chip or an antenna. The wireless networking unit 520 may be an antenna for wireless communication. The wireless networking unit 520 can process a job required for data transmission / reception by the femtocell base station 500 and can transmit or receive a signal for data transmission / reception. The processing unit 510 can transmit and receive data necessary for operation of the femtocell base station 500 by controlling the wireless networking unit 520.

The wireless networking unit 520 may receive the femtocell connection request message from the terminal 400. [

The processor 510 may analyze the information in the femtocell connection request message, for example, the traffic status of the macrocell, using the femtocell connection request message.

The processor 510 may estimate the average transmission rate of each of the one or more terminals connected to the femtocell cluster based on the information in the femtocell connection request message. The processing unit 510 may determine a cooperative unit of the femtocell cluster based on the average transmission rates of one or more UEs. A method for determining a cooperation unit will be described in detail below with reference to FIG.

The wired networking unit 530 can transmit and receive data to / from the gateway through a local backbone network. Through the gateway, one or more femtocell base stations may be interconnected.

6 is a signal flow diagram illustrating a method of operating a femtocell cluster according to an embodiment.

The terminal 610 may be one of the eight terminals 220-1, 220-2, 220-3, 220-4, 220-5, 220-6, 220-7, and 220-8 described above with reference to FIG. One or more can be supported. The terminal 610 may be the terminal 400 described above with reference to FIG. The processing unit, the storage unit and the networking unit of the terminal 610 may be the processing unit 410, the storage unit 420, and the networking unit 430, respectively, of the terminal 400.

The femtocell base station 620 may correspond to one or more of the five femtocell base stations 210-1, 210-2, 210-3, 210-4, and 210-5 described above with reference to FIG. The femtocell base station 620 may be the femtocell base station 500 described above with reference to FIG. The processing unit, the wireless networking unit, and the wired networking unit of the femtocell base station 620 may be the processing unit 510, the wireless networking unit 520, and the wired networking unit 530 of the femtocell base station 500, respectively.

The representative base station 630 determines cooperating units among the five femtocell base stations 210-1, 210-2, 210-3, 210-4 and 210-5 in the femtocell cluster 200 described with reference to FIG. The femtocell base station may be a femtocell base station. The representative base station 630 may be the femtocell base station 500 described above with reference to FIG. The control unit, the wireless networking unit and the wired networking unit of the representative base station 630 may be the control unit 510, the wireless networking unit 520 and the wired networking unit 530 of the femtocell base station 500, respectively.

The representative base station 630 may correspond to an electronic device, a computer system, or a server that determines cooperating units in the femtocell cluster 200. That is, the function of the representative base station 630 may be an electronic device for determining a cooperating unit that does not perform the function of a typical femtocell base station.

The femtocell base station 620 may be plural. The plurality of femtocell base stations may be interconnected with one gateway through a local backbone network. The representative base station 630 may be a base station selected to determine a cooperative unit among interconnected femtocell base stations.

In step 640, the processing unit of the terminal 610 may generate a femtocell connection request message.

The networking unit of the terminal 610 may transmit the femtocell connection request message to the wireless networking unit of the femtocell base station 620 or the wireless networking unit of the representative base station 630 in step 645. [

The wireless networking unit of the femtocell base station 620 or the wireless networking unit of the representative base station 630 may receive information on the communication state of the terminal 610 through the femtocell access request message.

In step 650, the networking unit of the femtocell base station 620 may transmit the information in the femtocell access request message or the femtocell access request message to the networking unit of the representative base station 630.

The networking unit of the representative base station 630 may receive information on the communication state of the terminal 610 through the femtocell access request message.

Information on the communication state of the terminal can be transmitted from each of a plurality of femtocell base stations in the femtocell cluster.

In step 660, the processing unit of the representative base station 630 may calculate the average transmission rate of the terminal 610 using the information on the communication state of the terminal 610. [

The processing unit of the representative base station 630 may calculate an average transmission rate of each of the UEs based on Equation (2).

는 단말 r의 평균 전송률일 수 있다.

는 펨토셀 클러스터 내에서 사용되는 협력 단위 및 단말 접속 V _i 하에서의 단말 u의 평균 전송률일 수 있다. 단말 u는 i 번째 펨토셀 클러스터의 단말들의 집합 U의 단말들 중 하나의 단말일 수 있다.here,

May be the average transmission rate of the terminal r .

May be the average transmission rate of the terminal u under the cooperative unit and the terminal connection V _i used in the femtocell cluster. The terminal u may be one of the terminals of the set U of the terminals of the i-th femtocell cluster.

The processing unit of the representative base station 630 may calculate or define V _i based on Equation (3) below.

V _i may be the current cooperative unit and terminal connection used in the i th femtocell cluster. V _i may be cooperative units and terminal connections determined for a plurality of layers of the i-th femtocell cluster. K may be the number of the plurality of layers. K may be an integer of 2 or more.

Here, the i- th femtocell cluster may be a femtocell cluster including one or more femtocell clusters in the heterogeneous cellular network system 100, including the terminal 610, the femtocell base station 620, or the representative base station 630.

The processing unit of the representative base station 630 may calculate C ^m and C ^f _u , _k based on the following Equation (4) and Equation (5).

Here, N _T may be the number of antennas of the macro cell base station 110. N ^m _{e ( i )} may be an estimated number of terminals connected to the macrocell associated with the ith femtocell cluster. s ( u , k ) may be the index of the cooperative unit corresponding to the terminal u in the kth layer. k may be an integer of 1 or more and K or less. Here, the cooperative unit to which the terminal u corresponds may refer to a cooperative unit including the femtocell base station to which the terminal u is connected.

는 i 번째 펨토셀 클러스터의 k 번째 레이어에서 l 번째 협력 단위를 구성하는 펨토셀 기지국들의 위치들의 집합일 수 있다.

May be a set of locations of the femtocell base stations constituting the lth cooperative unit in the kth layer of the ith femtocell cluster.

는 i 번째 펨토셀 클러스터의 k 번째 레이어에서 l 번째 협력 단위에 접속한 단말들의 위치들의 집합일 수 있다.

May be a set of positions of terminals connected to the lth cooperative unit in the kth layer of the i th femtocell cluster.

는 단말 u가 매크로셀 기지국(110)에 접속하였을 때의 평균 SNR일 수 있다.

는 단말 u가 펨토셀 기지국에 접속하였을 때의 k 번째 레이어에서의 평균 SNR일 수 있다.

May be the average SNR when the terminal u is connected to the macro cell base station 110. [

May be the average SNR at the kth layer when terminal u is connected to the femtocell base station.

및

를 계산할 수 있다.The processing unit of the representative base station 630 may be configured to perform the following processing based on Equation (6) and Equation (7)

And

Can be calculated.

는 단말 u 및 펨토셀 기지국 x 간의 평균 채널 이득일 수 있다. P _f 는 펨토셀의 평균 전송 전력일 수 있다. P _m 은 매크로셀의 평균 전송 전력일 수 있다. N ₀은 잡음의 평균 전력일 수 있다. X ^m은 근접한 매크로셀 기지국들의 위치들의 집합일 수 있다. X ^f 는 근접한 펨토셀 기지국들의 위치들의 집합일 수 있다.here,

May be an average channel gain between the terminal u and the femtocell base station x . P _f may be the average transmit power of the femtocell. P _m can be an average transmission power of the macro cell. N ₀ may be the average power of the noise. X ^m may be a set of locations of neighboring macro cell base stations. X ^f may be a set of locations of adjacent femtocell base stations.

In step 670, the processing unit of the representative base station 630 may determine a cooperative unit and a terminal connection of the femtocell base stations in the femtocell cluster based on the calculated average transmission rate.

If the femtocell clusters are distributed with an interval of more than a specific value, the processing unit of the representative base station 630 maximizes the network utility of each of the one or more femtocell clusters based on Equation (8) using the calculated average transmission rate .

Here, V ⁺ _i may be a cooperative unit and a terminal connection that maximizes the network utility.

를 계산할 수 있다.The processing unit of the representative base station 630 may be configured to determine

Can be calculated.

That is, the processing of the representative base station 630 may determine a cooperation unit of the i-th femtocell i th femtocell cluster by based on the average transmission rate of the UE maximizes the proportional fairness among the terminals in the i-th femtocell cluster in the cluster, the femtocell base station .

In the above-described step 660, the average transmission rate of the UE can be calculated according to the result of the existing cooperating unit and the UE connection. Further, in the above-described step 670, the cooperating unit and the terminal connection can be calculated using the average transmission rate of the terminal calculated in step 660. [ Thus, steps 660 and 670 can be performed repeatedly, and the results of the calculation of the average transmission rate of the terminal and the results of the determination of cooperating units can be fed back to each other. With the above feedback, the processing unit of the representative base station 630 can determine the most effective cooperative unit and terminal connection for heterogeneous cellular network system 100 and / or femtocell cluster data offloading.

In step 680, the processing unit of the representative base station 630 may generate a femtocell connection response message including information on the determined cooperating unit and the terminal connection.

In step 685, the wireless networking unit of the representative base station 630 may transmit a femtocell connection response message to the wireless networking unit of the femtocell base station 620 or the networking unit of the terminal 610.

The wireless networking unit of the representative base station 630 may transmit information on the cooperative unit and the terminal connection determined through the femtocell connection response message to the wireless networking unit of the femtocell base station 620 or the networking unit of the terminal 610. [

Information on the determined cooperating unit and terminal connection can be transmitted to each of a plurality of femtocell base stations in the femtocell cluster.

In step 690, the networking unit of the femtocell base station 620 may transmit the information in the femtocell access response message or the femtocell access request message to the networking unit of the terminal 400. [

The UE 400 can access the femtocell base station of one or more femtocell base stations in the femtocell cluster using the information on the determined cooperative unit and the terminal connection.

The processing unit of the representative base station 630 can determine the cooperation unit and the terminal connection by using the following initialization step and the first to eighth steps.

일 수 있다.The input of the algorithm may be X ^f _i , U _i , K and N ^G. The output of the algorithm is

Lt; / RTI >

Initialization step

k = 1, 2, ... , K may be initialized according to Equation (10) below.

Step 2

If the value of k is 1, the setting according to Equation (11) below can be performed. If the value of k is not 1, the setting according to Equation (12) below can be performed.

Step 2

The setting according to Equation (13) below can be performed.

에 대해 하기의 수학식 14 및 수학식 15에 따른 설정이 수행될 수 있으며,

로부터 최근접 펨토셀 기지국들인

가 결정될 수 있다.all

The setting according to the following equations (14) and (15) may be performed,

Lt; RTI ID = 0.0 > femtocell &

Can be determined.

Further, the setting according to the following equations (16) to (20) can be performed.

Step 3

가 선택될 수 있다.

는 하기의 수학식 21에 따라 설정될 수 있다.The terminal having the maximum matrix value

Can be selected.

Can be set according to the following equation (21).

Next, the setting according to the following equations (22), (23) and (24) can be performed.

Step 4

The second step and the third step may be repeated while the following expression (25) holds.

If Equation (26) is satisfied, the fifth step may proceed.

Step 5

에 대해서, 하기의 수학식 27 및 수학식 28에 따른 설정이 수행될 수 있다.all

The setting according to Equation (27) and Equation (28) below can be performed.

Step 6

The setting according to Equation (29) below can be performed.

Step 7

The setting according to the following equation (30) can be performed.

Step 8

이면, 하기의 수학식 31, 수학식 32 및 수학식 33에 따른 설정이 수행되고 제5 단계가 반복될 수 있다. k = 1, m _curr > m _prev and

, The setting according to Equations (31), (32) and (33) below may be performed and the fifth step may be repeated.

이면, 하기의 수학식 34 및 수학식 35에 따른 설정이 수행되고 제5 단계가 반복될 수 있다. k > 1

, The setting according to the following equations (34) and (35) may be performed and the fifth step may be repeated.

및 k < K인 경우, 또는 k > 1,

및 k < K인 경우에는 하기의 수학식 36에 따른 설정이 수행되고 제1 단계가 반복될 수 있다. k = 1,

And k < K , or k > 1,

And if k < K , the setting according to the following equation (36) may be performed and the first step may be repeated.

Otherwise, the steps may end.

The apparatus described above may be implemented as a hardware component, a software component, and / or a combination of hardware components and software components. For example, the apparatus and components described in the embodiments may be implemented within a computer system, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA) A programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For ease of understanding, the processing apparatus may be described as being used singly, but those skilled in the art will recognize that the processing apparatus may have a plurality of processing elements and / As shown in FIG. For example, the processing unit may comprise a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of the foregoing, and may be configured to configure the processing device to operate as desired or to process it collectively or collectively Device can be commanded. The software and / or data may be in the form of any type of machine, component, physical device, virtual equipment, computer storage media, or device , Or may be permanently or temporarily embodied in a transmitted signal wave. The software may be distributed over a networked computer system and stored or executed in a distributed manner. The software and data may be stored on one or more computer readable recording media.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions to be recorded on the medium may be those specially designed and configured for the embodiments or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

 While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI &gt; or equivalents, even if it is replaced or replaced.

100: Heterogeneous cellular network system
110: macro cell base station
610:
620: femtocell base station
630:

Claims (10)

A method for determining, by an electronic device, a cooperative unit of femtocell base stations in a femtocell cluster,
Receiving information on a communication state of a terminal;
Calculating an average data rate of the terminal using the information on the communication state;
Determining the cooperative unit based on the average rate; And
Transmitting information on the determined cooperative unit
And determining a cooperative unit of femtocell base stations. The method of claim 1,
Wherein the cooperative unit is determined for each of a plurality of layers of a subchannel. The method of claim 1,
The information on the communication state may include at least one of information on the traffic state of the macrocell, signal-to-noise ratio information for each of one or more femtocell base stations adjacent to the terminal, and information on the terminal. How to determine the unit. The method of claim 3,
Wherein the information on the traffic state of the macrocell includes at least one of the number of antennas of the macrocell base station of the macrocell, the average rate of transmission of the macrocell, and the number of terminals of the macrocell. How to. The method of claim 1,
Calculating the average data rate of the terminal and determining the cooperative unit are repeatedly performed;
And the result of the calculation of the average rate and the result of the determination of the cooperative unit are fed back to each other. The method of claim 1,
Wherein the cooperating unit is calculated based on a greedy algorithm. The method of claim 1,
Wherein the cooperative unit is determined by maximizing proportional fairness among terminals in the femtocell cluster. The method of claim 1,
Information about the communication state of the terminal is transmitted from each of the femtocell base stations,
And the information about the determined cooperative unit is transmitted to each of the femtocell base stations. The method of claim 1,
Wherein the information on the communication state of the terminal reflects the load of the macrocell and the location of the terminal. An electronic device for determining a cooperative unit of femtocell base stations in a femtocell cluster, comprising:
A networking unit which receives information on a communication state of a terminal and transmits information on the determined cooperative unit; And
A processor that calculates an average data rate of the terminal using the information on the communication state, and determines the cooperative unit based on the average data rate
.

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