KR101206916B1 - Method for sharing radio resources between femtocells and macrocells in mobile wireless access systems - Google Patents

Abstract

Disclosed is a method for sharing resources between a femtocell and a macrocell in a mobile radio access system for efficiently sharing resources of a femtocell and a macrocell in a mobile radio access system supporting a femtocell.
In the disclosed mobile radio access system, the resource sharing method of a femtocell and a macrocell determines interference of a femtocell due to the transmission of a femtocell based on information of a neighbor cell reported by a macrocell user and frequency partition (FP) allocation information. An interference determination step; Resource segmentation determination step of determining radio resource segmentation for each FP by using extracted resource usage allowance index information, macro cell service yield and average femtocell obtainable average capacity: and extracted resource usage allowance index information and radio resource segmentation information for each FP Transmitting a resource to the femto base station to share resources of the femtocell and the macrocell.

Description

Resource sharing between femtocell and macrocell in mobile radio access system {METHOD FOR SHARING RADIO RESOURCES BETWEEN FEMTOCELLS AND MACROCELLS IN MOBILE WIRELESS ACCESS SYSTEMS}

The present invention relates to a resource sharing method of a femtocell and a macrocell in a mobile radio access system for efficiently sharing resources of a femtocell and a macrocell in a mobile radio access system supporting a femtocell.

The IEEE 802.16 Working Group 16 and the 3rd Generation Partnership Project (3GPP), the standards bodies that define the next-generation air interface standards, are mobile radios that support femtocells to increase system efficiency and improve quality of service (QoS) in indoor environments. Standardization work is underway for access systems. A femto basestation is a low power, low cost mobile communication base station connected to an IP network via a broadband wired link.

That is, a femto base station is built in a home or small office (SOHO) by a user to provide the same service as a macro base station. Femtocells are classified into an open access femtocell, a closed access femtocell, and a hybrid access femtocell according to a user access control scheme. An open access femto base station provides a service connection of all user terminals passing nearby, similar to the existing macro base station.

On the other hand, the closed access femto base station permits access only to user terminals (hereinafter referred to as "member users") that are already registered and allowed to connect. Hybrid access femto base stations provide limited quality of service connectivity when not a member user. An open access femtocell and a hybrid access femtocell can overcome the interference problem through handover when the interference between cells is large. However, closed access femtocells can cause severe interference to macrocell users (non-member users) who are nearby and are not allowed to access other femtocell users.

Meanwhile, a conventional macrocell network (macrocell system) operates a fractional frequency reuse method (hereinafter referred to as 'FFR') in order to overcome the inter-cell interference problem. The FFR technique is a technique of applying a frequency reuse rate differently according to a user position in order to increase the data rate of a user terminal which is located at a cell boundary and receives a lot of interference from an adjacent cell.

That is, the entire frequency domain is divided into a plurality of frequency partitions (hereinafter referred to as FPs), and the transmission power of each FP is differentiated so that a user terminal located at a cell boundary allocates a high power FP to the cell. A centrally located user terminal is a technique for allocating a low power FP. Implementing femtocells in FFR-based macrocell networks can increase the spatial reuse rate of radio resources. This is because by allocating differential transmit power to each FP, more frequency reuse space is generated, allowing the femtocell to reuse the radio resources used by the macrocell with less interference.

As is known, a femtocell system has an advantage of improving the shadow area by using a femto base station instead of an existing repeater by overlapping tens to hundreds of femtocells in a macro cell, and reducing the load of the macro base station. However, the femtocell overlapping within the macro cell causes the following additional interference when the femtocell and the macro cell operate at the same frequency as compared to the existing macro cell network.

Macro-to-femto interference (hereinafter referred to as 'MFI'): Interference affecting femtocells due to macrocell transmission

2. Femto-to-macro interference (hereinafter referred to as 'FMI'): Interference affecting macrocell transmission due to femtocell transmission

3.Femto-to-femto interference (hereinafter referred to as 'FFI'): Inter-femtocell interference

The MFI is caused by the difference between the transmission area of the femtocell (10-50m) and the transmission area of the macrocell (500-1000m), and the path loss and transmission loss (due to the distance between the corresponding femtocell users from the neighboring macro base station) It is mainly affected by penetration loss.

FMI, as mentioned above, is an interference experienced by nearby non-member macrocell users due to closed access femtocell transmission. FMI can be mitigated by limiting the use of radio resources of interfering related femtocells, but this requires additional signaling procedures for determining the interfering related femtocells and limiting the use of radio resources.

FFI is affected by femtocell build density. That is, when a large number of femtocells operate around each femtocell user, they experience high mutual interference. An existing inter-cell interference control scheme can be applied for FFI mitigation.

1 is a diagram schematically illustrating an interference problem occurring in a two-tier network in which a femtocell is constructed.

When a femtocell uses the same frequency band as that used by a macro cell, interference between the macro cell and the femtocell can reduce not only the data rate but also the overall system capacity.

Accordingly, the present invention has been proposed to solve various problems occurring in resource sharing in a mobile radio access system supporting the femtocell as described above.

An object of the present invention is to provide a resource sharing method of femtocells and macrocells in a mobile radio access system for efficiently sharing resources of femtocells and macrocells.

Another problem to be solved by the present invention is the resource sharing of femtocells and macrocells in an efficient mobile radio access system that can increase the overall system capacity while mitigating interference occurring between macrocells and femtocells in a mobile radio access system supporting femtocells. To provide a way.

According to the present invention for solving the above problems, the method for sharing resources of a femtocell and a macrocell in a mobile radio access system,

An interference determination step of determining interference on the macrocell transmission due to the transmission of the femtocell based on the information of the neighbor cell reported by the macrocell user and the frequency partition (FP) allocation information;

An information extraction step of extracting resource usage allowance index information for each frequency partition of the femtocell;

A resource partitioning determination step of determining a radio resource partition for each FP by using the extracted resource usage allowance indicator information, macrocell service yield, and the attainable average capacity of each femtocell:

And transmitting the extracted resource use allowance index information and the radio resource division information for each FP to the femto base station, and sharing the resources of the femtocell and the macrocell.

According to the present invention, it is possible to provide stable services to femtocell users while ensuring wireless transmission for macrocell users in a mobile radio access system supporting femtocells, and using optimal radio resources for sharing radio resources between macrocells and femtocells. Providing a solution has the advantage of increasing the overall system capacity.

1 is an exemplary view schematically showing an interference problem occurring in a mobile communication system in which an existing femtocell is constructed.
2 is a flowchart illustrating a resource sharing method between a femtocell and a macrocell in a mobile radio access system according to the present invention.
3 is a diagram illustrating an operation of a partial frequency reuse scheme in a macro cell network.
4 illustrates an example of radio resource use of a femtocell under a partial frequency reuse environment in accordance with an embodiment of the present invention.
5 is a diagram illustrating a frequency band division structure according to an embodiment of the present invention.
6 is a schematic operation of the macro cell user protection scheme 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, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

FIG. 3 is a diagram illustrating an operation of a partial frequency reuse scheme in a macro cell network. In FIG. 3, a frequency band is divided into four FPs having the same number of subchannels. FP0 has frequency reuse of 1 and is set to the same transmit power in all macrocells. The other three FPs are allocated transmit power at the ratio of 3-α-β: α: β. In this case, three adjacent cells exclusively set the high power FP as shown in FIG. 3 to minimize the inter-cell interference at the cell boundary. The base stations that manage each cell assign the user located at the cell center to the low power FP and the user located at the cell boundary to the high power FP.

When the femtocell is constructed in the FFR environment as shown in FIG. 3, an example of the use of radio resources of the femtocell is shown in FIG. 4. In FIG. 4, it is assumed that a femtocell and a macrocell share all radio resources. Each femtocell according to the present invention determines the use FP according to the following two policies.

1. Does not interfere with wireless transmissions for nearby overlaid macrocell users.

2. Does not interfere with wireless transmissions for neighboring macrocell users in the vicinity.

For example, in FIG. 4, femtocells 2 and 3 (f2 and f3) may use FPs other than FP2 according to the radio resource usage policy 1 of the femtocell proposed in the present invention. However, since FP1 has a large MFI from an overlapping macrocell, FP2 and FP3 may be used by femtocells 2,3 (f2, f3). The femtocells 4, 5, and 6 (f4, f5, f6) are far from the macro base stations around and experience negligible MFI in all FPs, but resource usage is limited according to the radio resource usage policy of the femtocell according to the present invention. That is, femtocell 4 (f4) can not use the FP1 because the FMI can be added to the surrounding macrocell 1 user, and at the same time, FP2 cannot be used to prevent FMI because the macrocell 2 user is using the FP2. Note that femtocell 1 (f1) located at the center of the cell cannot share radio resources with the macrocell at all due to the high MFI. Accordingly, in order to provide a stable service to a femtocell, a femtocell dedicated band is required even if the femtocell uses the radio resources used in the macrocell as an opportunity.

5 is a diagram illustrating a frequency band division structure according to an embodiment of the present invention. In a mobile radio access system supporting a femtocell, one macrocell and femtocells constructed in the geographic service area of the macrocell are called macro-privileged groups (MPGs) for each FP as shown in FIG. 5. Radio resources are used according to a radio resource partitioning structure composed of a " FDG " and a femto-dedicated group. The MPG is a radio resource interval that can be freely used by the macrocell, and the femtocell can use radio resources in the MPG in an opportunity (in accordance with wireless resource usage policies 1 and 2) without disturbing the macrocell user. On the other hand, the FDG is a radio resource interval used exclusively for the femtocell in the overlapping macrocell region, and the corresponding overlapping macrocell cannot use the radio resource in the FDG. Therefore, each femtocell can freely use the radio resources in the FDG in consideration of the radio resource usage policy 2 only.

로 표현한다. 여기서, K는 주파수 대역내의 총 FP수이고,

는 FP k에서 MPG를 위해 할당된 무선 자원의 비율을 나타낸다. 즉, FP당 F개의 서브채널로 구성된다면,

서브채널이 MPG에 속하고,

서브채널이 FDG에 속한다. 이때,

는 "floor" 연산자를 의미한다.The radio resource division structure for each macro cell region includes a radio resource division vector,

. Where K is the total number of FP in the frequency band,

Denotes the ratio of radio resources allocated for MPG at FP k. In other words, if it consists of F subchannels per FP,

The subchannel belongs to the MPG,

The subchannel belongs to the FDG. At this time,

Means the "floor" operator.

In the present invention, in order to maximize the spatial frequency efficiency while ensuring wireless transmission for the macro cell user, the optimal radio resource partition vector is determined through the optimization problem of Equation 1 below. The optimization problem according to the present invention aims at maximizing the total sum of cell yields of macrocells and femtocells in one macro cell region, and has a constraint on maintaining fairness between macrocell user rates and femtocell user rates.

subject to

에 대해서 예상되는 매크로셀 수율로서,

, η은 매크로셀과 펨토셀간 fairness 파라미터, T_f,i(α)는 펨토셀 i에서의 예상되는 셀 수율을 나타낸다.Where N _f is the total number of femtocells within the macrocell region, U _{m, k} is the number of macrocell users assigned to FP k, U _f is the number of users connected to one pimtocell, and T _{m, k} is expected at FP k The macrocell throughput, T _m (α)

Expected macrocell yield for

is the fairness parameter between the macrocell and the femtocell, and T _{f, i} (α) represents the expected cell yield in femtocell i.

Here, T _{m, k} is calculated using service information for each user managed by the macro base station, and T _{f, i} (α) is determined according to Equation 2 below.

delete

는 펨토셀 i의 FP k의 MPG에서의 예상 셀 용량,

는 펨토셀 i의 FP k의 FDG에서의 예상 셀 용량을 나타낸다.Here, ω _{i, k} is the resource availability indicator according to femto-to-overlaid macrocell interference, hereinafter referred to as 'RAIO' for femtocell i due to FMI to overlapping macrocells. Φ _{i, k} is the resource availability indicator according to femto-to-neighbor macrocell interference (hereinafter referred to as 'RAIM') for FP k in femtocell i due to FMI to neighboring macrocells. ),

Is the expected cell capacity at FP k MPG of femtocell i,

Denotes the expected cell capacity at FDG of FP k of femtocell i.

는 FP k의 MPG/FDG에서 측정된 평균 신호 대 간섭 및 잡음비(signal to interference plus noise, SINR)를 이용하여

와 같이 계산될 수 있다. At this time,

Using the average signal to interference plus noise (SINR) measured at MPG / FDG of FP k,

It can be calculated as

Here, W represents a frequency band for one subchannel, and Γ represents a signal-to-interference and noise ratio (SINR gap parameter).

에 대한 선형식이 된다. 따라서, 매크로 사용자와 펨토셀 사용자간 공평성 유지를 위한 제약 조건을 만족시키면서 전체 시스템 용량을 최대화할 수 있는 최적의 α^ㆍ를 용이하게 구할 수 있다.
본 발명에서는 펨토셀 전송으로부터 매크로셀 사용자를 보호하기 위해 FP기반의 FMI억제 절차를 수행한다. 즉, 도 2에 도시된 바와 같이, 매크로 기지국(또는, 자원 관리 객체)은 핸드오버를 위해 사용되고 있는 매크로셀 사용자의 이웃 셀 정보(neighbor cell information)과 FP 할당 정보를 이용하여 영역 내에 위치하는 펨토셀의 FMI 여부를 결정한다(S10 ~ S30).
즉, 매크로셀 사용자가 보고하는 이웃 셀의 정보와 주파수 파티션(FP) 할당 정보를 기반으로 펨토셀의 전송으로 인해 매크로셀 전송에 미치는 간섭을 결정하게 된다. 여기서 이동 무선 접속시스템에서 각 매크로셀/펨토셀은 사용자가 셀을 감지할 수 있도록 셀 고유 식별자를 포함하는 프리앰블을 주기적으로 전송하게 된다. 따라서 매크로셀 사용자는 각 셀로부터 송신된 프리앰블 신호의 수신 전력을 측정할 수 있다. 이때, 한 펨토셀로부터의 수신 신호 전력(received signal strength)이 미리 정한 임계치(시스템 설정 값으로 주어짐) 이상이 되면 그 펨토셀의 전송으로 인해 매크로셀 사용자가 간섭을 겪을 수 있게 된다. 상기 임계치는 매크로 기지국으로부터의 수신 신호전력/펨토셀로부터의 수신신호 전력과 같이 수신 신호 전력비로 결정하거나, 펠토셀로부터의 수신 신호 전력 > -50dBm과 같이 절대 수신 전력으로 결정할 수 있다. 따라서 수신 신호 전력과 임계치의 비교를 통해 간섭을 결정할 수 있게 된다.
다음으로, 펨토셀의 주파수 파티션별 자원사용 허용지표 정보를 추출한다(S40). 여기서 자원사용 허용지표는 펨토셀이 각 FP를 사용할 수 있는지에 대한 지표로서, 주지한 ω_i,k=1이면 펨토셀 i가 FP k를 사용 가능하다는 것이고, ω_i,k=0이면 펨토셀 i가 FP k를 사용할 수 없다는 것을 나타낸다. 예를 들어, 자신에게 연결된 매크로셀 사용자가 현재 FP k로 할당되어 있고 펨토셀 i를 포함하는 이웃셀 정보를 보고하였다면, 자원 사용 허용 지표를 ω_i,k=0으로 설정하고, 펨토 기지국 i에 FP k를 사용하지 못하도록 자원 사용 제한 요구 메시지를 송신하게 된다. 따라서 이러한 자원 사용 제한 요구 메시지에 포함된 자원사용 허용지표 정보를 추출하게 되는 것이다.
그리고 상기 추출한 자원사용 허용지표 정보, 매크로 셀 서비스 수율 및 각 펨토셀의 획득 가능한 평균 용량을 이용하여 각 FP별 무선 자원 분할을 결정하게 된다(S50).
즉, 주지한 [수학식1]에서 목표는 매크로셀과 매크로셀 영역내에 위치한 펨토셀들의 수율의 총 합(공간적 주파수 효율)을 최대로 하는 것이다. 단, 매크로셀 사용자 전송률과 펨토셀 사용자 전송률이 일정 비율(η) 내에서 유지되도록 무선 자원 분할 벡터를 결정한다(수학식 1의 제약 조건).
모든 주파수 대역을 매크로셀과 함께 사용하는 경우, 매크로 기지국으로부터 가까이에 위치한 펨토셀은 높은 MFI로 인해 펨토셀 수율이 현저히 떨어지게 되고, 이를 해결하기 위해 주파수 대역의 일부를 FDG로 할당하는 데, FDG의 할당 기준은 상기 [수학식 1]의 제약 조건을 만족해야한다. [수학식1]에서 각 부분을 구체적으로 설명하면, 매크로셀은 MPG 무선자원만을 사용하므로 α_k에 비례하여 셀 수율이 결정되고, 펨토셀은 FDG무선자원과 MPG무선자원을 모두 사용하므로 펨토셀 수율은 [수학식2]와 같이 FDG에서의 셀 수율(수학식2의 첫 번째 부분)과 MPG에서의 셀 수율(수학식2의 두 번째 부분)의 합으로 표현할 수 있다. 여기서 MPG무선자원은 매크로셀 사용자 보호 동작에 따라 사용 제약이 따르므로,

가 곱해지고, FDG무선자원은 중첩 매크로셀은 사용하지 않으므로 중첩 매크로셀만 고려하면 사용제약이 없다. 그러나 자원 분할이 매크로셀 단위로 결정되므로 중첩 매크로셀에서 FDG인 무선 자원도 이웃 매크로셀에서는 MPG로 사용할 수 있고, 펨토 기지국이 중첩 매크로셀 경계에 위치한다면 FDG에서도 이웃 매크로셀에서 사용자를 보호하기 위해 사용 제약이 따른다, 따라서 FDG에서의 부분 셀 수율 계산시

가 곱해진다. 따라서 이러한 조건을 기반으로 각 FP별 무선 자원 분할을 결정하게 된다.
그리고 상기 추출한 자원사용 허용지표 정보 및 FP별 무선 자원 분할 정보를 펨토 기지국에 전송하여, 펨토셀은 사용 허용 지표 정보에 따라 무선 자원 사용이 제한된다(S60 ~ S70).
즉, 추출한 자원사용 허용지표 정보 및 FP별 무선 자원 분할 정보를 펨토 기지국에 전송하여, 펨토셀과 매크로셀의 자원을 공유하게 된다. 예컨대, 도 5에 보는 바와 같이, 동일한 주파수 대역을 매크로셀과 펨토셀이 공유하는 데, α_k로 명시된 주파수 부분은 매크로셀과 해당 매크로셀 영역내의 펨토셀들이 같이 사용하고, 1-α_k로 명시된 주파수 부분은 펨토셀들만 사용하도록 자원을 공유하게 된다.The femtocell resource usage allowance indicators ω _{i, k} and φ _{i, k} are determined through the macrocell user protection scheme described below, and other values are calculated through the scheduling result and the user channel state.

Is a linear equation for. Therefore, while satisfying the constraints for maintaining fairness between the macro user and the femtocell user, it is possible to easily obtain the optimum α ^· that can maximize the total system capacity.
In the present invention, FP-based FMI suppression procedure is performed to protect macrocell users from femtocell transmission. That is, as shown in Figure 2, the macro base station (or resource management object) is a femtocell located in the area using the neighbor cell information (Neighbor cell information) and FP allocation information of the macro cell user that is being used for handover Determine whether or not the FMI (S10 ~ S30).
That is, interference of the femtocell due to the transmission of the femtocell is determined based on the information of the neighbor cell reported by the macrocell user and the frequency partition (FP) allocation information. In the mobile radio access system, each macrocell / femtocell periodically transmits a preamble including a cell unique identifier so that a user can detect the cell. Therefore, the macro cell user can measure the received power of the preamble signal transmitted from each cell. At this time, when the received signal power from a femtocell is greater than a predetermined threshold (given as a system setting value), the macrocell user may experience interference due to the transmission of the femtocell. The threshold may be determined by the received signal power ratio, such as the received signal power from the macro base station / the received signal power from the femtocell, or may be determined as the absolute received power, such as received signal power from the Feltocell> -50 dBm. Therefore, interference can be determined by comparing the received signal power with a threshold.
Next, resource usage allowance index information for each frequency partition of the femtocell is extracted (S40). Here, the resource usage allowance index indicates whether a femtocell can use each FP. If ω _{i, k} = 1, femtocell i can use FP k, and if ω _{i, k} = 0, femtocell i is FP. Indicates that k cannot be used. For example, if a macro cell user connected to the user is currently assigned neighbor cell information including femtocell i and is assigned to FP k, the resource usage indicator is set to ω _{i, k} = 0, and the FP is transmitted to the femto base station i. A resource usage limit request message is sent to prevent the use of k. Therefore, the resource usage allowance indicator information included in the resource usage restriction request message is extracted.
Then, the radio resource division for each FP is determined using the extracted resource usage allowance index information, the macro cell service yield, and the attainable average capacity of each femtocell (S50).
That is, in Equation 1, the goal is to maximize the total sum of the yields (spatial frequency efficiency) of the macrocells and femtocells located in the macrocell region. However, the radio resource partition vector is determined such that the macro cell user rate and the femtocell user rate are maintained within a predetermined ratio η (constraints of Equation 1).
When all frequency bands are used in conjunction with macrocells, femtocells located close to the macro base station significantly reduce the femtocell yield due to high MFI, and to solve this problem, a portion of the frequency band is allocated to the FDG. Must satisfy the constraint of Equation 1 above. In detail describing each part in [Equation 1], since the macrocell uses only the MPG radio resources, the cell yield is determined in proportion to α _k , and since the femtocell uses both the FDG radio resources and the MPG radio resources, the femtocell yield is As shown in [Equation 2], it can be expressed as the sum of the cell yield in FDG (first part of Equation 2) and the cell yield in MPG (second part of Equation 2). In this case, MPG wireless resources are restricted in use according to the macro cell user protection operation.

Is multiplied and FDG radio resources do not use overlapping macrocells, so there is no restriction in considering only overlapping macrocells. However, since resource division is determined in units of macrocells, radio resources, which are FDGs in overlapping macrocells, can also be used as MPGs in neighboring macrocells. Use constraints, so when calculating partial cell yield in FDG

Is multiplied. Therefore, the radio resource division for each FP is determined based on these conditions.
Then, the extracted resource use allowance index information and FP radio resource partitioning information are transmitted to the femto base station, and the femtocell is limited to use of radio resources according to the use allowance index information (S60 to S70).
That is, the extracted resource use allowance indicator information and the radio resource division information for each FP are transmitted to the femto base station to share the resources of the femtocell and the macrocell. For example, as shown in FIG. 5, the same frequency band is shared between the macrocell and the femtocell, wherein the frequency portion designated by α _k is used by the macrocell and the femtocells in the corresponding macrocell region together, and is designated by 1-α _k . The part will share resources to use only femtocells.

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In more detail, each macrocell user reports information of a neighbor cell whose received signal is above a certain threshold, which means that the macrocell user may experience high FMI from the neighbor cell (femtocell). That is, when the femtocell included in the neighbor cell information uses the FP assigned to the macro cell user, the macro cell user may experience high FMI. Therefore, the macro base station configures a resource use allowance index matrix K × N _f using neighboring cell information and FP allocation information of the user, and transmits resource use allowance index information to each femto base station.

6 shows an embodiment of a macro cell user protection operation according to the present invention.

In FIG. 6, femtocell 1 (f1) is included in the neighbor cell list of macrocell users 1-1 (mMS1-1), 1-3 (mMS1-3), and 1-4 (mMS1-4). MPG radio resources of FP0 and FP1 allocated to -1 (mMS1-1), 1-3 (mMS1-3), and 1-4 (mMS1-4) cannot be used.

Since femtocell 3 (f3) is included in the neighbor cell list of macrocell users 1-2 (mMS1-2), MPG radio resources of FP1 allocated to macrocell users 1-2 (mMS1-2) cannot be used. Here, femtocell 3 (f3) is located within the service area of macrocell 1 and shares frequency resources with macrocell 1, but may interfere with radio transmission for neighboring macrocell users. That is, all radio resources of FP2 that are included in the neighbor cell list of macrocell user 2-1 (mMS2-1) and assigned to macrocell user 2-1 (mMS2-1) cannot be used. In this case, the reason for limiting all radio resources in the corresponding FP, not the MPG radio resource limitation, is that MPG / FDG radio resource division may be different because the radio resource division vector is determined for each macrocell region independently. The macro cell 2 base station performs a signaling procedure that requires a corresponding FP usage restriction for the femto base station to which the FMI is expected as an overlapping macro base station.

The macro base station manages a resource use allowance indicator matrix (?) Composed of RAIO and a resource use allowance indicator matrix (Φ) composed of RAIM. The matrix Ω to prevent FMI into its cell is constructed as follows.

Here, ω _{k, i} has a value of 0 when femtocell i is included in the neighbor cell list of any macro cell user assigned to FP k, and has a value of 1 otherwise. Therefore, if ω _{k, i} is 0, femtocell i cannot use MPG resources in FP k, and if ω _{k, i} is 1, femtocell i can use MPG resources in FP k. The macro base station updates Ω according to the neighbor cell information and the FP allocation information of the lower user.

The matrix Φ to adjacent macrocells is then constructed as follows.

Here, φ _{i, k} has a value of 0 when femtocell i is included in a neighbor cell list of any macrocell user assigned to FP k in neighboring macrocells, and has a value of 1 otherwise. Therefore, if φ _{i, k} is 0, femtocell i cannot use not only MPG but also FDG resources in FP k. The macro base station updates the matrix? According to the FP usage restriction request received from neighboring macrocells.

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 invention as defined in the appended claims and their equivalents. Of course, such modifications are within the scope of the claims.

Claims (11)

In a method for sharing resources of a femtocell and a macrocell in a mobile radio access system,
An interference determination step of determining interference on the macrocell transmission due to the transmission of the femtocell based on the information of the neighbor cell reported by the macrocell user and the frequency partition (FP) allocation information;
An information extraction step of extracting resource usage allowance index information for each frequency partition of the femtocell;
A resource partitioning determination step of determining a radio resource partition for each FP by using the extracted resource usage allowance indicator information, macrocell service yield, and the attainable average capacity of each femtocell:
Transmitting the extracted resource use allowance indicator information and radio resource division information for each FP to a femto base station, and sharing a resource between the femtocell and the macrocell, and including a resource sharing step of the femtocell and the macrocell in the mobile radio access system. Resource sharing method.
The method of claim 1, wherein the resource sharing step,
A method of sharing resources between a femtocell and a macrocell in a mobile radio access system, wherein the radio resources are divided into a macro priority group (MPG) and a femto dedicated group (FDG) for each frequency partition.
The method of claim 2, wherein the resource sharing step,
A method for sharing resources of a femtocell and a macrocell in a mobile radio access system, wherein the resources of the femtocell and the macrocell are shared using a partial frequency reuse (FFR) operation of the macrocell system.
The method according to claim 1, wherein the resource partition determination step,
Resource usage allowance index information considering femto-to-macro interference (FMI) between the overlapping macrocell and the neighboring macrocell;
An average service yield per frequency partition (FP) of the macro cell user;
A femtocell in a mobile radio access system, characterized by determining radio resource division for each FP to maximize the overall frequency efficiency in a macro cell region using an average capacity per subchannel that can be obtained for each frequency partition (FP) of each femtocell. And macrocell resource sharing method.
The method of claim 1, wherein the resource sharing step,
Femto-to-macro interference (FMI) is suppressed by restricting the use of radio resources in the frequency partition (FP) allocated to the macro cell user for the femtocell included in the information of the neighbor cell reported by the macro cell user. A method for sharing resources between femtocells and macrocells in a mobile radio access system.
The method according to claim 2 or 5, wherein the femtocell opportunistically uses radio resources in the macro priority group within a range that does not disturb the overlapping macrocell user and the neighboring macrocell user, and does not disturb the neighboring macrocell user. A method for sharing resources between a femtocell and a macrocell in a mobile radio access system, wherein the radio resources in the femto dedicated group are freely used within a range.
The method according to claim 1, wherein the information extraction step,
Extracting resource usage allowance index for suppressing femto-to-macro interference (FMI) to overlapping macrocells and resource usage allowance index for suppressing femto-to-macro interference (FMI) to neighboring macrocells A method for sharing resources between femtocells and macrocells in a mobile radio access system.
The method according to claim 1, wherein the information extraction step,
A first resource usage allowance indicator matrix for suppressing femto-to-macro interference to cell users and a second resource use allowance indicator matrix for suppressing femto-to-macro interference to adjacent macrocell users. A method of sharing resources between a femtocell and a macrocell in a mobile radio access system, characterized in that for managing.
The method of claim 8, wherein the resource sharing step,
Whenever the first and second resource usage allowance indicator matrices are updated, the resource sharing method of the femtocell and the macrocell in the mobile radio access system is performed. .
The method of claim 9, wherein the resource sharing step,
The Femto-to-macro interference (FMI) matrix is constructed to the cell user using the neighbor cell information and the FP allocation information for the lower user, and the neighbor macrocell user is requested according to the FP usage restriction request received from the neighboring macrocells. A method for resource sharing between a femtocell and a macrocell in a mobile radio access system, characterized by updating a femto-to-macro interference (FMI) matrix.
The method of claim 9, wherein the resource sharing step,
If the femtocell included in the neighbor cell information of the downstream user is not a femtocell in the base station area, the message including the femtocell identifier and the FP information assigned to the user below is transmitted to the medium managing the femtocell and the FMI ( A method of sharing resources between a femtocell and a macrocell in a mobile radio access system, characterized by suppressing femto-to-macro interference.

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