WO2015168865A1

WO2015168865A1 - Method and apparatus for interference coordination of edge user equipment

Info

Publication number: WO2015168865A1
Application number: PCT/CN2014/076899
Authority: WO
Inventors: Gang Wang; Su YI; Lei Jiang; Zhennian SUN
Original assignee: Nec Corporation
Priority date: 2014-05-06
Filing date: 2014-05-06
Publication date: 2015-11-12

Abstract

Embodiments of the present invention relate to methods and apparatuses for interference coordination of edge user equipment(UE). A method comprises obtaining a dominant interferer identifier of an edge UE in at least one first cell. The method further comprises based, at least in part, on the obtained dominant interferer identifiers, determining a first subset of resource blocks for each of the at least one first cell from a set of available resource blocks,and determining a second subset of resource blocks for each of the at least one first cell from a part of the set of available resource blocks subtracting the first subset corresponding to each of the at least one first cell. The method further comprises informing the first and second subsets to each of the at least one first cell. The first subset contains a first predetermined number of resource blocks to be used by the edge UE of each of the at least one first cell, and the second subset contains a second predetermined number of resource blocks to be blanked by each of the at least one first cell.

Description

METHOD AND APPARATUS FOR INTERFERENCE COORDINATION OF EDGE

USER EQUIPMENT

^D FIELD OF TECHNOLOGY

[0001] Embodiments of the present invention generally relate to communication technology, and more specifically, to a method and apparatus for interference coordination of edge user equipment (UE). ⁰ BACKGROUND

[0002] There have been several proposals to meet the continually increasing traffic demands and high quality expectations from end users for mobile communication services, for example, through a straightforward increasing of the number of macro base stations in a network, or through deploying a heterogeneous network that is overlaid with additional lower-power and5 low-complexity small base stations. Several small base stations may be placed in one macro cell and share a set of resource blocks in the heterogeneous network. These small cells may or may not share the same frequency band with the macro cell. If co-channel deployment is considered, the inference experienced by a small cell mainly comes from the macro cell. In a non-co-channel deployment, small cells may experience interference from other closely-placed0 small cells.

[0003] In both network deployments, the interference problem of UE placed in the edge area of a macro cell or a small cell always exists. Especially, in the heterogeneous network deployment, where small cells are closely placed and a multi-subframe scheduling or similar scheme may be used due to low mobility and slow time varying of small cells, the interference5 level of edge UEs may be increased. Therefore, interference mitigation of edge UEs is an important aspect of mobile communication systems.

[0004] CN Patent Publication No. 201 1 10048784.1 , entitled "RNTP-based method of interference suppression in LTE system," filed on March 1 , 201 1 , discloses that a base station selects subcarriers satisfied a certain condition and allocates the selected subcarriers to an edge0 of the base station with lowest SINR (Signal to Interference plus Noise Ratio), and the base station also informs one neighbor base station that is coordinating with it to disable the selected edge subcarriers. The neighbor base station selects subcarriers for its edge users in a similar manner.

[0005] However, in the solution disclosed by CN Patent Publication No. 201 1 10048784.1 ,5 subcarrier scheduling is coordinated between only two base stations and without being aware of those subcarriers having been scheduled, other base stations adjacent to these two base stations may still schedule the selected edge subcarriers for their edge UEs, which may then resulting in more subcarrier conflicts among edge UEs in a number of adjacent base stations.

SUMMARY

[0006] In order to address at least one of the foregoing and other potential problems, embodiments of the present invention propose a method and apparatus for interference coordination of edge UE.

[0007] In a first aspect, embodiments of the present invention provide a method in a coordinating cell for interference coordination of edge UE. The method comprises obtaining a dominant interferer identifier of an edge UE in at least one first cell. The method further comprises based, at least in part, on the obtained dominant interferer identifiers, determining a first subset of resource blocks for each of the at least one first cell from a set of available resource blocks, and determining a second subset of resource blocks for each of the at least one first cell from a part of the set of available resource blocks subtracting the first subset corresponding to each of the at least one first cell. The method further comprises informing the first and second subsets to each of the at least one first cell. The first subset contains a first predetermined number of resource blocks to be used by the edge UE of each of the at least one first cell, and the second subset contains a second predetermined number of resource blocks to be blanked by each of the at least one first cell.

[0008] In a second aspect, embodiments of the present invention provide a method in a coordinated cell for interference coordination of edge UE. The method comprises a base station of a first cell receiving a first indicator and a second indicator from a second cell, wherein the first indicator indicating a first subset of resource blocks containing a first predetermined number of resource blocks to be used by an edge UE of the first cell, and the second indicator indicating a second subset of resource blocks containing a second predetermined number of resource blocks to be blanked by the first cell. The method also comprises scheduling resource blocks for the edge UE in accordance with the first indicator. The method further comprises blanking at least one resource block in accordance with the second indicator.

[0009] In a third aspect, embodiments of the present invention provide an apparatus in a coordinating cell for interference coordination of edge UE. The apparatus comprises a first obtaining unit configured to obtain a dominant interferer identifier of an edge UE in at least one first cell. The apparatus also comprises a resource block determining unit configured to determine a first subset of resource blocks for each of the at least one first cell from a set of available resource blocks, and determining a second subset of resource blocks for each of the at least one first cell from a part of the set of available resource blocks subtracting the first subset corresponding to each of the at least one first cell, based, at least in part, on the obtained dominant interferer identifiers. The apparatus further comprises a resource block informing unit configured to inform the first and second subsets to each of the at least one first cell. The first subset contains a first predetermined number of resource blocks to be used by the edge UE of each of the at least one first cell, and the second subset contains a second predetermined number of resource blocks to be blanked by each of the at least one first cell.

[0010] In a fourth aspect, embodiments of the present invention provide an apparatus in a coordinated cell for interference coordination of edge UE. The apparatus comprises an indicator receiving unit configured to a first indicator and a second indicator from a second cell, wherein the first indicator indicating a first subset of resource blocks containing a first predetermined number of resource blocks to be used by an edge UE of the first cell, and the second indicator indicating a second subset of resource blocks containing a second predetermined number of resource blocks to be blanked by the first cell. The apparatus also comprises a resource block scheduling unit configured to schedule resource blocks for the edge UE in accordance with the first indicator. The apparatus further comprises a resource block blanking unit configured to blank at least one resource block in accordance with the second indicator.

[0011] Through the following description, it would be appreciated that in accordance with embodiments of the present invention, a cell, such as a macro cell, may assist in interference coordination of edge UE for at least one first cell. The macro cell may determine a first subset contained resource blocks to be used by the edge UE of each of the at least one first cell and a second subset contained resource blocks to be blanked by each of the at least one first cell. The first and second subsets may be informed to each of the at least one first cell. In this way, resource blocks to be used by the edge UEs may be coordinated by the macro cell and interference of the edge UEs may be reduced. In addition, some resource blocks are coordinated to be blanked, which may further improve performance of the edge UE and reduce the interference to other first cell. Other advantages achieved by embodiments of the present invention will become apparent through the following descriptions.

DESCRIPTION OF DRAWINGS

[0012] Through the following detailed description with reference to the accompanying drawings, the above and other objectives, features and advantages of embodiments of the present invention will become more comprehensible. In the drawings, several embodiments of the present invention will be illustrated in an example and non-limiting manner, wherein:

[0013] Figure I illustrates a flowchart of a method for interference coordination of edge UE in accordance with an example embodiment of the present invention;

[0014] Figure 2 illustrates schematically cells participating in the interference coordination in accordance with an example embodiment of the present invention;

[0015] Figure 3 shows a schematic diagram of resource blocks from which the first and second subset of each of the small cells may be determined in accordance with an example embodiment of the present invention;

[0016] Figure 4 illustrates a schematic diagram of transmitting power of resource blocks in accordance with an example embodiment of the present invention;

[0017] Figure 5 illustrates a flowchart of a method for interference coordination of edge UE in accordance with another example embodiment of the present invention;;

[0018] Figure 6 illustrates a block diagram of an apparatus for interference coordination of edge UE in accordance with an example embodiment of the present invention; and

[0019] Figure 7 illustrates a block diagram of an apparatus for interference coordination of edge UE in accordance with another example embodiment of the present invention.

[0020] Throughout the drawings, the same or corresponding reference symbols refer to the same or corresponding parts.

DESCRIPTION OF EXAMPLE EMBODIMENTS

[0021] Principles of the present invention will now be described with reference to various example embodiments illustrated in the drawings. It should be appreciated that depiction of these embodiments is only to enable those skilled in the art to better understand and further implement the present invention, not intended for limiting the scope of the present invention in any manner.

[0022] Usually in mobile communication systems, macro cells or small cells may schedule resource blocks or subcarriers from a set of available resources alone in terms of best performance for UEs in their coverage area, or as disclosed by CN Patent Publication No. 201 1 10048784.1 , two neighbor base stations can schedule subcarriers for their own edge UEs by informing the other base station not to use the same subcarriers for the edge UE. However, in the current dense network deployment, especially in the heterogeneous network deployment, a number of macro cells or small cells are closely placed and may interfere edge UEs of each other. Interference coordination should be performed among those cells.

[0023] Therefore, embodiments of the present invention propose methods and apparatuses for interference coordination of edge UE. The interference coordination may be assisted by a macro cell or a small cell. The assisting cell may suggest a subset of resource blocks to the coordinated cells, which may be determined, from an overall view of the assisting cell, as a better subset of resource blocks to be used by the edge UEs of the coordinated cells. Also, the assisting cell may also suggest a subset of resource blocks to be blanked by the coordinated cells in order to reducing interference to adjacent cells.

[0024] In a case where a macro cell uses different resource blocks from that of small cells within it, the interference coordination may be conducted among a plurality of small cells or among a plurality of macro cells. Otherwise, in a case where a macro cell and small cells schedule the same resource blocks, the interference coordination may be conducted among a plurality of macro cells and small cells. As used herein, the term "small cell" refers to a cell supported by a low-powered base station such as a picocell or a femtocell.

[0025] In embodiments described in details below, a macro-cell assisted interference coordination for a plurality of small cells is presented by way of example. It should be noted that, in some other embodiments, a macro cell may assist interference coordination for a plurality of macro cells or both macro cells and small cells including the assisting macro cell itself. It should also be noted that, in some other embodiments, a small cell may assist interference coordination for a plurality of macro cells, small cells or both macro and small cells. The scope of the present invention is not limited in this regard.

[0026] Reference is first made to Figure 1 which shows a flowchart of a method 100 for interference coordination of edge UE in accordance with an example embodiment of the present invention.

[0027] At step S I 01 , a macro cell obtains a dominant interferer identifier of an edge UE in at least one small cell. The dominant interferer of the edge UE is considered as the dominant interferer of this small cell in this invention. In one example embodiment, each of the at least one small cell may have at least two active UEs. The reason is that if one UE is active in a small cell, the small cell may traditionally schedule as many as available resource blocks to this UE to meet its throughput or data rate requirement, even if this UE is an edge UE. As such, a small cell with two or more active UE may be considered to participate in interference coordination. In another example, the small cell may have one active UE.

[0028] In accordance with one embodiment of the present invention, the edge UE of each of the at least one small cell may have a signal quality lower than other UEs in the small cell and the signal quality may be lower than a first predetermined threshold. Since usually UEs in the edge area of a small cell may be interfered by other adjacent cells, the present invention intends to improve the performance of edge UEs by the interference coordination. A UE with lowest signal quality may need to reduce interference and improve performance more than other UEs in the small cell. That is, one small cell may indicate one UE with worst performance as its edge UE. In addition, from an overall view, the signal quality of the UE may also be lower than a first predetermined threshold. For example, if there are five small cells within a macro cell, and only signal qualities of three of the five edge UEs in respective small cells are lower than the first predetermined threshold, then the three small cells serving these three edge UEs may participate into the interference coordination. In other embodiments, all small cells within the macro cell may participate into the interference coordination and their edge UEs are those whose signal qualities are lowest in respective small cells. The small cells may report the information of their edge UE, for example, identifiers of the edge UE to the macro cell such that the macro cell may identify those edge UE. Considering the mobility of UEs, the edge UE in each small cell may change.

[0029] In some example embodiments, the signal quality may be measured by RSRQ (Reference Signal Received Quality). In other example embodiments, the signal quality may be measured by RSRP (Reference Signal Received Power).

[0030] In accordance with one embodiment of the present invention, the dominant interferer identifier of the edge UE in each of the at least one small cell identifies another small cell having interference level higher than a second predetermined threshold to the edge UE in each of the at least one small cell. In one example, the dominant interferer of each small cell may have the highest interference level to the edge UE in each small cell. The edge UE of a small cell may be interfered by several network, entities. Usually the edge UE is located in the edge area of its serving small cell and may be more adjacent to another small cell in the heterogeneous network deployment. The other small cell may be the interferer that having the highest interference level to this edge UE and may then be the dominant interferer of this small cell. In accordance with other embodiments, the dominant interferer of an edge UE may be a macro cell.

[0031] In one example, the dominant interferer identifier may be a cell identifier of the other small cell. In other examples, the dominant interferer identifier may be any other identifier that can identify the dominant interferer.

[0032] In this step, the dominant interferer identifiers may be received from the at least one small cell in one embodiment. In this embodiment, the dominant interferer identifiers may be transmitted over backhaul links between the at least one small cell and the macro cell.

[0033] The method 100 then proceeds to step S I 02, where the macro cell determines a first subset of resource blocks for each of the at least one small cell from a set of available resource blocks, and determines a second subset of resource blocks for each of the at least one small cell from a part of the set of available resource blocks subtracting the first subset corresponding to each of the at least one small cell.

[0034] In this step, the first subset may contain a first predetermined number of resource blocks to be used by the edge UE of each of the at least one small cell, and the second subset may contain a second predetermined number of resource blocks to be blanked by each of the at least one small cell.

[0035] Usually small cells within a macro cell may share a set of available resource blocks. As such, the macro cell may determine the first subsets of resource blocks to be used by the edge UEs of the participating small cells so as to reduce interference between those edge UEs. In addition, in order to further mitigate interference, the macro cell may also determine the second subsets of resource blocks to be blanked by the participating small cells. That is, the macro cell suggests to the participating small cells not to schedule the resource blocks contained in the second subsets for their edge UEs or other UEs.

[0036] In some embodiments, the first predetermined number may be determined by the macro cell and may not be the same for all participating small cells. For example, the first predetermined number may be defined as:

R, = [B / N, ] (1) where R, represents the first predetermined number corresponding to the th small cell among the participating small cells; B represents the number of available resource blocks; N, represents the number of UEs served by the /th small cell; and [ ] represents determining a smaller integer that is closely to B/N, . In some other embodiments, each of the at least one small cell may determine the first predetermined number based on their scheduling requirement and then inform it to the macro cell. The first predetermined number may be determined in any other manner, and the scope of the present invention is not limited in this regard. Similarly, the second predetermined number may either be determined by the macro cell or by the small cell.

[0037] The determining of the first and second subsets will be discussed in more details below.

[0038] The method 100 then proceeds to step SI 03, where the macro cell informs the first and second subsets to each of the at least one small cell. In accordance with some embodiments of the present invention, the macro cell may send to each of the at least one small cell a first bitmap indicating resource blocks contained in the first subset and a second bitmap indicating resource blocks contained in the second subset.

[0039] The available resource blocks for small cells within the macro cell may be numbered and the order may be aware by those small cells. As such, a bitmap in a form such as

"00011 100 000" may be used to inform the resource blocks contained in each subset, wherein the number of bits in the bitmap may be the quantity of available resource blocks. For example, assuming there are 50 available resource blocks, a 50-bit bitmap of "00 1 11 1000" may be used to indicate one first subset, wherein a bit "1" may indicate a resource block to be used by the edge UE and the position of the bit "1" in the bitmap may indicate the specific resource block in the set of available resource blocks. In another example, a bit "0" may be used to indicate the resource block to be used while a bit "1" may indicate other resource block not to be used. In other examples, a 50-bit bitmap of "00 0000001 1" may be used to indicate one second subset, wherein a bit "1" may indicate a resource block to be blanked by the corresponding small cell and the position of the bit "1" may indicate the specific resource block in the set of available resource blocks. In another example, a bit "0" may be used to indicate the resource block to be blanked while a bit "1" may indicate other resource block not to be blanked.

[0040] It should be noted that in other embodiments of the present invention, the macro cell may inform the first and second subsets to each of the at least one small cell through other manners. For example, each of the available resource blocks may be identified by an identifier and then the macro cell may inform the identifiers of resource blocks contained in the first and second subsets respectively to each of the at least one small cell. The scope of the present invention is not limited in this regard.

[0041] As discussed in the above, a first subset and a second subset may be determined by the macro cell for each of the participating small cell and then may be informed to a corresponding small cell. The determining of the first subset and the second subset is now described in the following.

[0042] As for each of the at least one small cell, it is expected to have resource blocks in the first subset causing a high level of channel quality for the edge UE. However, as the limited available resource blocks, some small cells have to compromise for other small cells. It is expected in the present invention to conduct interference coordination among the participating small cells and to lower down the interference level of the edge UEs. [0043] In accordance with some embodiments, when determining the first and second subsets for each of the at least one small cell, the following Steps 1-3 may be performed:

[0044] Step 1. Ranking the at least one small cell by a predetermined rule.

[0045] In the interference coordination, the macro cell may determine the first and second subsets for the at least one small cell one by one.

[0046] In accordance with some embodiments of the present invention, the predetermined rule may be based, at least in part, on a random order, or an order based on frequency of each of the at least one small cell being a dominant interfere of other small cells or on a total throughput of each of the at least one small cell. For example, if a small cell among the participating small cells is the dominant interferer of five other small cells, which is higher than other small cells, then this small cell may be ranked at the topmost. In another example, the participating small cells may be ranked by magnitudes of their total throughput in ascending order. In yet another example, the participating small cells may be ranked randomly. In other examples, the at least one small cell may be ranked by considering both the frequency and the total throughput of each small cell. It should be noted that the at least one small cell may be ranked according to any other rule. For example, the at least one small cell may be ranked based on signal qualities or throughputs of their edge UEs.

[0047] As illustrated in Figure 2, three small cells, Small cell 1 , Small cell 2 and Small cell 3, are participated in the interference coordination. Small cell 1 is the dominant interferer of Small cell 3, and Small cell 3 is the dominant interferer of Small cell 2. When determining the first and second subsets for these three small cells, they may be ranked by a random order such as Small cell 1 ->Small cell 2 -» Small cell 3.

[0048] Step 2. Selecting the first predetermined number of resource blocks from the set of available resource blocks as the first subset for the small cell ranked the topmost, and selecting the second predetermined number of resource blocks from a part of the set of available resource blocks subtracting the first subset corresponding to the small cell ranked the topmost as the second subset for the small cell ranked the topmost.

[0049] For the small cell ranked the topmost, its first and second subsets are determined firstly. Therefore, in some embodiments, the macro cell may select the first predetermined number of resource blocks randomly from the set of available resource blocks and select the second predetermined number of resource blocks randomly from a part of the set of available resource blocks subtracting the selected first subset.

[0050] In other embodiments, the macro cell may also obtain channel state information of the edge UE of this small cell. As a result, when determining the first subset for the small cell ranked the topmost, the macro cell may select resource blocks causing a channel quality of the edge UE larger than a third predetermined threshold from selectable resource blocks based on the channel state information of the edge UE. Since the available resource blocks are not selected for other small cells when determining the first and second subsets for the small cell ranked the topmost, the macro cell may select better resource blocks for the edge UE in this small cell as the first subset, such that this edge UE may have better performance. In one example, resources blocks causing best channel quality of the edge UE may be selected. When determining the second subset for the small cell ranked the topmost, the macro cell may select resource blocks randomly from the rest selectable resource blocks, as those resource blocks are not used by the edge UE.

[0051] Also referring to Figure 2, the macro cell may first determine the first and second subsets for the topmost Small cell 1. The macro cell may select the first predetermined number of best resource blocks from the available resource blocks as the first subset, and then select the second predetermined number of resource blocks randomly from the remaining available resource blocks as the second subset.

[0052] Step 3. Determining the first and second subsets for other small cells in the ranked order, and for each of the other small cells, the following Steps 3.1 -3.3 may be performed.

[0053] In order to reduce interference and improve performance for the edge UEs, when determining the first and second subsets for each of the other small cells, certain rules should be complied. Detailed description is as Steps 3.1-3.3.

[0054] Step 3.1. Determining an interfering small cell resource block set and an interfered small cell resource block set corresponding to each of the other small cells from the determined small cell resource block sets, in accordance with the obtained dominant interferer identifiers.

[0055] In this case, the obtained dominant interferer identifiers may be used to determine the interfering relationship between those small cells. The interfering small cell resource block set may contain resource blocks in a first subset corresponding to another small cell that is the dominant interferer of the small cell in question, because the other small cell has high interference level to this small cell in question. The interfered small cell resource block set may contain resource blocks in first subset(s) corresponding to other small cell(s) whose dominant interferer(s) is this small cell in question, because this small cell in question has high interference level to the other small cell(s).

[0056] As discussed below, it will be noted that, if a small cell is not the dominant interferer of other small cells whose first subset has been determined, and if any of the small cells whose first subset has been determined is not the dominant interferer of this small cell, then the macro cell may select the first and second subsets for this small cell in a way similar to the small cell ranked the topmost.

[0057] For example, based on the ranked order, the first and second subsets of Small cell 2 may be determined after Small cell 1. According to the dominant interferer identifiers of these three cells, Small cell 1 (the first subset of which is determined) is not the dominant interferer of Small cell 2 and Small cell 2 is not the dominant interferer of Small cell 1. As such, the macro cell may select the first and second subsets for Small cell 2 in a way similar to Small cell 1. For example, for Small cell 2, beset resource blocks may be selected from the set of available resource blocks as the first subset and resource blocks may be selected from the remaining available resource blocks randomly as the second subset.

[0058] Step 3.1.1. Searching, from the small cells the first subsets of which have been determined, whether there is a small cell identified by the dominant interferer identifier of each of the other small cells.

[0059] For example, also referring to Figure 2, the first and second subsets of Small cell 3 may be determined after Small cell 1 and Small cell 2. For Small cell 3, the macro cell finds that the dominant interferer identifier of Small cell 3 indicates, from Small cell 1 and Small cell 2 (the first subset of which has been determined), that Small cell 1 is its dominant interferer.

[0060] Step 3.1.2. Determining the first subset of the searched small cell as the interfering small cell resource block set, or determining the interfering small cell resource block set as a null set if no small cell is searched.

[0061] As discussed above, a small cell may have one dominant interferer, and the interfering small cell resource block set may contain a first subset of another small cell that has interference to this small cell in question.

[0062] Also, as illustrated in Figure 2, since Small cell 1 is the dominant interferer of Small cell 3, the macro cell may determine the first subset of Small cell 1 , denoted as Ωι, as the interfering small cell resource block set of Small cell 3.

[0063] Step 3.1.3. Searching, from the small cells the first subsets of which have been determined, whether there are small cells the dominant interferer identifiers of which identify each of the other small cells.

[0064] For example, also referring to Figure 2, the macro cell finds that the dominant interferer identifier of Small cell 2 (the first subset of which has been determined) identifies Small cell 3 as its dominant interferer.

[0065] Step 3.1.4. Determining a union set of the first subsets of the searched small cells as the interfered small cell resource block set, or determined the interfered small cell resource block set as a null set if no small cell is searched.

[0066] As a small cell may be the dominant interferer of one or more other small cells, the interfered small cell resource block set may contain one or more first subsets of the other small cells interfered by this small cell in question.

[0067] As illustrated in Figure 2, the macro cell may determine the first subset of Small cell 2, denoted as Ω₂, as the interfered small cell resource block set of Small cell 3.

[0068] Step 3.2. Determining the first subset for each of the other small cells, in accordance with a comparison of the first predetermined number with the quantities of resource blocks in the interfering and interfered small cell resource block sets.

[0069] The detailed description of the comparison is presented in (al)-(a4).

[0070] (al ) If the first predetermined number is less than or equal to the quantity of resource blocks in a third subset, the macro cell may select the first predetermined number of resource blocks from the third subset as the first subset of each of the other small cells, wherein the third subset is a part of the set of available resource blocks subtracting the interfering and interfered small cell resource block sets.

[0071] In this case, since resource blocks in the third subset are neither selected by the dominant interferer of the small cell in question, nor selected by any of small cells interfering the edge UE of this small cell in question, those resource blocks may be used by the edge UE of this small cell for the purpose of interference mitigation.

[0072] In other words,, assuming the set of available resource blocks is Ω, and the interfering and interfered small cell resource block sets Ωι, Ω₂ and Ω are shown in Figure 3. If the first predetermined number -¾ corresponding to Small cell 3 meets ≤|Ω|-|Ω_[ υ Ω₂ | , the third subset may be represented as Ω, υΩ₂ . The macro cell may select resource blocks from Ω, υΩ₂ for Small cell 3 as its first subset.

[0073] (a2) If the first predetermined number is less than or equal to the quantity of resource blocks in a fourth subset, the macro cell may select resource blocks from the third subset and then select the remaining resource blocks from a part of the fourth subset subtracting the third subset, as the first subset of each of the other small cells, wherein the fourth subset is a part of the set of available resource blocks subtracting the interfering small cell resource block set.

[0074] In this case, resource blocks in the fourth subset are those not selected by the dominant interferer of this small cell. The third subset may be contained in the fourth subset. For the purpose of interference mitigation of the edge UE in this small cell, if there is no enough resource blocks in the third subset, more resource blocks may be selected in the other part of the fourth subset. It should be noted that if the first predetermined number is less than or equal to the quantity of resource blocks in the third subset, which means that it is also less than the quantity of resource blocks in the fourth subset, then in an example the first predetermined number of resource blocks may be only selected from the third subset, or in other examples, some of resource blocks may be selected from the third subset and more resource blocks may be selected from the other part of the fourth subset.

[0075] The total number of selected resource blocks should be the first predetermined number corresponding to this small cell.

[0076] As one example, as illustrated in Figure 3, if the first predetermined number corresponding to Small cell 3 is ^ and ^, < |Ω| -|Ω, |„ the fourth subset may be represented as

Ω_ι . The macro cell may select resource blocks from the third subset Ω, υΩ₂ and then select more resource blocks from the other part Ω, η Ω- of the fourth subset. Totally ■¾ resource blocks are selected.

[0077] (a3) If the first predetermined number is less than or equal to the quantity of resource blocks in a fifth subset, the macro cell may select resource blocks from the fourth subset and then select the remaining resource blocks from a part of the fifth subset subtracting the fourth subset, as the first subset of each of the other small cells, wherein the fifth subset is a part of the set of available resource blocks subtracting an intersection set of the interfering and interfered small cell resource block sets.

[0078] In this case, resource blocks in the fifth subset are either selected by the dominant interferer of the small cell in question or by any of small cells whose dominant interferer is this small cell in question. The fourth subset may be contained in the fifth subset. As a result, for the purpose of mitigating interference for the edge UE in this small cell by doing the best, if not enough resource blocks are in the fourth subset, more resource blocks may be selected in the other part of the fifth subset.

[0079] It should be noted that if the first predetermined number is less than or equal to the quantity of resource blocks in the third or fourth subset, which means that it is also less than the quantity of resource blocks in the fifth subset, then in an example the first predetermined number of resource blocks may be only selected from the third or fourth subset, or in other examples, some of resource blocks may be selected from the third or fourth subset and more resource blocks may be selected from the other part of the fifth subset.

[0080] The total number of selected resource blocks should be the first predetermined number corresponding to this small cell. [0081] As one example, as illustrated in Figure 3, if the first predetermined number ¾ corresponding to Small cell 3 meets -ΐΩ, η Ω-Ι, the fifth subset may be represented as ^ π Ω, . The macro cell may select resource blocks from the fourth subset Ω, and then select more resource blocks from the other part Ω, Ω₂ οΓ the fifth subset. Totally resource blocks are selected.

[0082] (a4) The macro cell may select resource blocks from the fifth subset and then selecting the remaining resource blocks from a part of the set of available resource blocks subtracting the fifth subset, as the first subset of each of the other small cells.

[0083] As one example, as illustrated in Figure 3, if the first predetermined number does not meet any of conditions in (al)-(a3), then the macro cell may select first select resource blocks in the fifth subset Ω, η Ω₂ , and select more resource blocks from the other part Ω, η Ω₂ of the set Ω. Totally R₃ resource blocks are selected. In other examples, resource blocks are first selected from the third subset, and then from the part of the fourth subset subtracting the third subset, and then from the part the fifth subset subtracting the fourth subset and finally from the set Ω subtracting the fifth subset, until resource blocks are selected.

[0084] It is noted that in some cases Ω, η Ω₂ may be a null set, and then the fifth subset may be equal to the set of available resource blocks. In general the first predetermined number may be at least less than or equal to the quantity of available resource blocks.

[0085] In (al)-(a4), the comparison result of the first predetermined number and the quantities of resource blocks in the interfering and interfered small cell resource block sets are considered, and corresponding first subset may be determined. It should be noted that if the first predetermined number meets two or more of (al )-(a4), the first subset may be determined by any one of them. In other embodiments, (al)-(a4) are performed as their priority order listed in above, and if the first predetermined number meets any one of (al)-(a4), the first subset may be determined in this step. For example, by performing the comparison in the order of (al) to (a4) and if |Ω| -|Ω, ^ I^ < |Ω| -|Ω, | , then all resource blocks in the third subset

Ω, υΩ₂ may be selected and the remaining resource blocks are selected from the other part

Ω, Ω₂ of the fourth subset.

[0086] Step 3.3. Determining the second subset for each of the other small cells, in accordance with a comparison of the second predetermined number with the quantities of resource blocks in the interfering and interfered small cell resource block sets. [0087] As discussed blow, it should be noted that, the second subset of this small cell in question may be determined in a reverse priority order as when determining its first subset as it is expected to choose blocks that have been selected in the first subsets of other small cells to be blanked.

[0088] (bl) If the second predetermined is less than or equal to the quantity of resource blocks in an intersection set of the interfering and interfered small cell resource block sets, selecting the second predetermined number of resource blocks from the intersection set as the second subset for each of the other small cells.

[0089] In this case, since resource blocks in the intersection set are selected by both of the dominant interferer of this small cell and by any of other small cells whose dominant interferer is this small cell, those resource blocks may not working well for this small cell and thus may be blanked.

[0090] By way of example, as shown in Figure 3, if the second predetermined number E₃ corresponding to Small cell 3 meets E₃≤ |Ω, n Ω₂1 , the macro cell may select E₃ resource blocks from the intersection set Ω, η Ω₂ for Small cell 3 as its second subset.

[0091] (b2) If the second predetermined is less than or equal to the quantity of resource blocks in the interfering small cell resource block set, selecting resource blocks from the intersection set and then selecting the remaining resource blocks from a part of the interfering small cell resource block set subtracting the intersection set, as the second subset for each of the other small cells.

[0092] It is noted that the intersection set in (bl) may be contained in the interfering small cell resource block set. In this case, if there is no enough resource blocks in the intersection set, more resource blocks may be selected from the interfering small cell resource block set.

[0093] It should also be noted that if the second predetermined number is less than or equal to the quantity of resource blocks in the intersection set, which means that it is also less than the quantity of resource blocks in the interfering small cell resource block set, then in an example, the second predetermined number of resource blocks may be only selected from the intersection set, or in other examples, some of resource blocks may be selected from the intersection set and more resource blocks may be selected from the other part of the interfering small cell resource block set.

[0094] By way of example, as shown in Figure 3, if the second predetermined number E₃ corresponding to Small cell 3 meets E₃≤ |Ω[ | _} the macro cell may first select resource blocks in the intersection set Ω₁ η Ω₂ and then select more resource blocks from the other part Q, n Q₂ of the interfering small cell resource block set. Totally £₃ resource blocks are selected.

[0095] (b3) If the second predetermined number is less than or equal to the quantity of resource blocks in a union set of the interfering and interfered small cell resource block sets, selecting resource blocks from the interfering small cell resource block set and then selecting resource blocks from a part of the union set subtracting the interfering small cell resource block set, as the second subset for each of the other small cells.

[0096] It is noted that the interfering small cell resource block set may be contained in the union set. In this case, if there is no enough resource blocks in the interfering small cell resource block set, more resource blocks may be selected from the part of the union set subtracting the interfering small cell resource block set. If the intersection set of the interfering and interfered small cell resource block sets is a null set, it means that more resource blocks may be selected from the interfered small cell resource block sets.

[0097] It should also be noted that if the second predetermined number is less than or equal to the quantity of resource blocks in the intersection set or in the interfering small cell resource block set, which means that it is also less than the quantity of resource blocks in the union set, then in an example, the second predetermined number of resource blocks may be only selected from the intersection set or the interfering small cell resource block set, or in other examples, some of resource blocks may be selected from the intersection set or the interfering small cell resource block set and more resource blocks may be selected from the other part of the union set.

[0098] By way of example, as shown in Figure 3, if the second predetermined number

E₃ corresponding to Small cell 3 meets £₃ < [Ω, u H₂ | , the macro cell may first select resource blocks in the interfering small cell resource block set Ω_[ and then select more resource blocks from the other part Ω, η Ω₂ of the union set. Totally E₃ resource blocks are selected.

[0099] (b4) Selecting resource blocks from the union set and then selecting a part of the remaining resource blocks from the set of available resource blocks subtracting the union set, as the second subset for each of the other small cells.

[00100] As one example, as illustrated in Figure 3, if the second predetermined number does not meet any of conditions in (b l)-(b3), then the macro cell may first select resource blocks in the union set Ω^ Ω₂ and then select more resource blocks from the other part Ω, ^ Ω. οί the set Ω. Totally £₃ resource blocks are selected. In other examples, resource blocks are first selected from the intersection set, and then from the part of the interfering small cell resource block set subtracting the intersection set, and then from the part the union set subtracting interfering small cell resource block set, and finally from the set Ω subtracting the union set, until E resource blocks are selected.

[00101] In (bl)-(b4), resource blocks in the first subset of each of the other small cells are not selected when selecting resource blocks for the second subset of each of the other small cell.

[00102] In (b l)-(b4), the comparison result of the second predetermined and the quantities of resource blocks in the interfering and interfered small cell resource block sets are considered, and corresponding second subset may be determined. It should be noted that if the second predetermined number meets two or more of (bl)-(b4), the second subset may be determined by any one of them. In other embodiments, (bl)-(b4) are performed as their priority order listed in above, and if the second predetermined number meets any one of (bl)-(b4), the second subset may be determined in this step. For example, by performing the comparison in the order of (bl) to (b4) and if |Ω, ΓΊ Ω₂1 < E₃≤ |Ω, | , then all resource blocks in the intersection subset Ω, n Ω. may be selected and the remaining resource blocks are selected from the other part Ω, η Ω₂ of the interfering small cell resource block set.

[00103] According to the above discussion in (al)-(a4) and (bl)-(b4), it may also be understand that if a small cell is not a dominant interferer of other small cells whose first subset has been determined, and if any of the small cells whose first subset has been determined is not the dominant interferer of this small cell, then the interfering and interfered small cell resource block sets corresponding to this small cell may be determined as null sets. Under this condition, even if the first and second subsets of this small cell are determined according to actions discussed in (al)-(a4) and (bl)-(b4), it may be appeared that the first and second subsets of this small cell is determined in a way similar to the small cell ranked the topmost.

[00104] In accordance to further embodiments of the present invention, the macro cell may further obtain channel state information of the edge UE of the at least one small cell. As a result, when determining the first subset for each of the at least one small cell, selecting the resource blocks causing a channel quality of the edge UE larger than a third predetermined threshold from selectable resource blocks based on the channel state information of the edge UE. Correspondingly, resource blocks in the first set may be better for the edge UE.

[00105] In one embodiment, edge UEs may transmit the channel state information (CSI) to the macro cell via a dual connectivity. The edge UE may periodically report the CSI, and the report period may be longer than normal CSI feedback period. [00106] In another embodiment, each small cell may receive the CSI from the edge UE and then may transmit it to the macro cell. In this embodiment, the CSI may be transmitted over backhaul links between the small cell and the macro cell. The macro cell may obtain the CSI through any other method, and the scope of the present invention is not limited in this regard.

[00107] In accordance with further embodiments of the present invention, the macro cell may determine the first and second subsets for each of the at least one small cell periodically and then inform the determined first and second subsets to the corresponding small cell. The period of the channel state information reporting can be designed to match the period of the interference coordination conducted by the macro cell. In some embodiments, every time the macro cell determines the first and second subsets for each of the at least one small cell, it may rank the at least one small cell by a different rule.

[00108] In accordance with further embodiments of the present invention, a transmitting power of resource blocks in the first subset to be used by the edge UE may be increased to improve the performance of the edge UE. At the same time, resource blocks in the second subset may be blank by the small cell, in order to maintain the total transmitting power of the small cell and also to reduce interference to other cells. In one embodiment, the macro cell may inform each of the at least one small cell to increase the transmitting power corresponding to the resource blocks in the first subset by a first power adjustment. The first power adjustment may be based, at least in part, on the total transmitting power of each of the at least one small cell, the first and second predetermined numbers. Usually the total transmitting power of a small cell should be maintained, therefore, there may be a tradeoff between the second predetermined number and the first power adjustment. Usually, the first power adjustment may be expected to be as high as possible, while the second predetennined number (the number of resource blocks to be blanked) may be expected to be as low as possible. The relationship of the second predetermined number and the first power adjustment may be defined as:

AP

B_ B_

lolal (2)

Where B represents the number of available resource blocks; N, represents the number of UEs served by the fth small cell; [ ] represents determining a smaller integer that is closely to B/N, ; and [B/N_t ] represents the first predetermined number. AP represents the first power adjustment; E_l represents the second predetermined number of the fth small cell; P_AVG represents the average transmitting power of UEs in the th small cell; and P_lolnl represents the total transmitting power of the /th small cell.

[00109] In some examples the reasonable power adjustment for a small cell may be at most 3 dB and in some examples, the reasonable second predetermined number may be less than 8. However, the second predetermined number and the first power adjustment may be of any other magnitude, and the scope of the present invention is not limited in this regard. In Figure 4, the power PEU of resource blocks in the first subset to be used by the edge UE are shown. The power PEU is larger than the average power P_AVG of other resource blocks of the same small cell by a first power adjustment ΔΡ. Also as illustrated in Figure 4, resource blocks in the second subsets are blanked by Small cells 1 -3. That is, those resource blocks in the second subset may not be used by the corresponding small cells.

[00110] Usually the macro cell plays a role as a coordinator and suggests the first and second subsets to small cells participating in the interference coordination. The small cells may or may not schedule resource blocks as suggested by the macro cell. Reference now made to Figure 5, where a method 500 for interference coordination of edge UE performed in the small cell side is illustrated in accordance to some example embodiments of the present invention.

[00111] At step S501, a small cell receives a first indicator and a second indicator from a macro cell, wherein the first indicator indicating a first subset of resource blocks containing a first predetermined number of resource blocks to be used by an edge UE of the small cell, and the second indicator indicating a second subset of resource blocks containing a second predetermined number of resource blocks to be blanked by the small cell.

[00112] As discussed above, the first and second indicators may be bitmaps or other identifier identifying respective resource blocks.

[00113] The method 500 then proceeds to step S502, where the small cell schedules resource blocks for the edge UE in accordance with the first indicator.

[00114] In some embodiments, the small cell may schedule all resource blocks indicated by the first indicator to the edge UE. In some other embodiments, due to other reasons, for example, the small cell may prefer to schedule one or more of the resources blocks indicated by the first indicator to other UEs rather than the edge UE, the remaining resource blocks indicated by the first indicator may be scheduled to the edge UE. In other embodiments, the small cell may decide not to schedule any resource block indicated by the first indicator to the edge UE but schedule other resource blocks to the edge UE.

[00115] The method 500 then proceeds to step S502, where the small cell blanks at least one resource block in accordance with the second indicator.

[00116] In some embodiments, the small cell may blank all resource blocks indicated by the second indicator. In some other embodiments, due to other reasons, for example, the small cell may prefer to schedule one or more of the resources blocks indicated by the second indicator to other UE rather than blanking them, the remaining resource blocks indicated by the second indicator may be blanked. In other embodiments, the small cell may decide not to blank any resource block indicated by the second indicator, or may blank at least one of other resource blocks rather than those indicated by the second indicator.

[00117] As discussed in above, while blanking some resource blocks, in order to maintain the total transmitting power of the small cell and also to improve the performance of the edge UE, the transmitting power of resource blocks in the first subset to be used by the edge UE may be increased. In accordance with some embodiments, the small cell may increase a transmitting power corresponding to resource blocks scheduled for the edge UE by a first power adjustment.

[00118] In some example embodiments, the first power adjustment may be informed by the macro cell. In some other example embodiments, the first power adjustment may be determined by the small cell. The determining manner of the first power adjustment may be similar as discussed above. It should be noted that, if the small cell decide not to schedule resource blocks to the edge UE and blank resource blocks as suggested by the macro cell, when determining the first power adjustment, the first predetermined number may be the number of resource blocks actually scheduled to the edge UE, and the second predetermined number may be the number of resource blocks actually blanked by the small cell.

[00119] As discussed in above, when participating into the interference coordination of edge UE that is conducted by the macro cell, the small cell may also report information of the edge UE to the macro cell via a backhaul link with the macro cell. The information may comprise at least one of an identifier, channel state information and dominant interferer identifier of the edge UE.

[00120] Figure 6 shows a block diagram of an apparatus 600 for interference coordination of edge UE in accordance with one example embodiment of the present invention is shown. As shown, the apparatus 600 comprises a first obtaining unit 601 configured to obtain a dominant interferer identifier of an edge UE in at least one first cell. The apparatus 600 also comprises a resource block determining unit 602 configured to determine a first subset of resource blocks for each of the at least one first cell from a set of available resource blocks, and determining a second subset of resource blocks for each of the at least one first cell from a part of the set of available resource blocks subtracting the first subset corresponding to each of the at least one first cell, based, at least in part, on the obtained dominant interferer identifiers, wherein the first subset contains a first predetermined number of resource blocks to be used by the edge UE of each of the at least one first cell, and the second subset contains a second predetermined number of resource blocks to be blanked by each of the at least one first cell. The apparatus 600 further comprises a resource block informing unit 603 configured to inform the first and second subsets to each of the at least one first cell.

[00121] In some example embodiments, each of the at least one first cell has at least two active UEs. In some example embodiments, the edge UE of each of the at least one first cell has a signal quality lower than other UEs in the first cell and the signal quality is lower than a first predetermined threshold. In some other example embodiments, the dominant interferer identifier of the edge UE in each of the at least one first cell identifies another first cell having an interference level higher than a second predetermined threshold to the edge UE in each of the at least one first cell.

[00122] In some example embodiments, the resource block determining unit 602 may comprise a ranking subunit configured to rank the at least one first cell by a predetermined rule; a first determining subunit configured to select the first predetermined number of resource blocks from the set of available resource blocks as the first subset for the first cell ranked the topmost, and selecting the second predetermined number of resource blocks from a part of the set of available resource blocks subtracting the first subset corresponding to the first cell ranked the topmost as the second subset for the first cell ranked the topmost; and a second determining subunit configured to determine the first and second subsets for other first cells in the ranked order, and for each of the other first cells, the second determining subunit is configured to: determine an interfering first cell resource block set and an interfered first cell resource block set corresponding to each of the other first cells from the determined first subsets, in accordance with the obtained dominant interferer identifiers, determine the first subset for each of the other first cells, in accordance with a comparison of the first predetermined number with the quantities of resource blocks in the interfering and interfered first cell resource block sets, and determine the second subset for each of the other first cells, in accordance with a comparison of the second predetermined number with the quantities of resource blocks in the interfering and interfered first cell resource block sets.

[00123] In some example embodiments, the predetermined rule may be based, at least in part, on a random order, or an order based on frequency of each of the at least one first cell being a dominant interfere of other first cells or on a total throughput of each of the at least one first cell.

[00124] In some example embodiments, the second determining subunit may be further configured to search, from the first cells the first subsets of which have been determined, whether there is a first cell identified by the dominant interferer identifier of each of the other first cells; determine the first subset of the searched first cell as the interfering first cell resource block set, or determining the interfering first cell resource block set as a null set if no first cell is searched; search, from the first cells the first subsets of which have been determined, whether there are first cells the dominant interferer identifiers of which identify each of the other first cells; and determine a union set of the first subsets of the searched first cells as the interfered first cell resource block set, or determined the interfered first cell resource block set as a null set if no first cell is searched.

[00125] In some example embodiments, the second determining subunit may be further configured to at least one of: if the first predetermined number is less than or equal to the quantity of resource blocks in a third subset, selecting the first predetermined number of resource blocks from the third subset as the first subset of each of the other first cells, wherein the third subset is the part of the set of available resource blocks subtracting the interfering and interfered first cell resource block sets; if the first predetermined number is less than or equal to the quantity of resource blocks in a fourth subset, selecting resource blocks from the third subset and then selecting the remaining resource blocks from the part of the fourth subset subtracting the third subset, as the first subset of each of the other first cells, wherein the fourth subset is the part of the set of available resource blocks subtracting the interfering first cell resource block set; if the first predetermined number is less than or equal to the quantity of resource blocks in a fifth subset, selecting resource blocks from the fourth subset and then selecting the remaining resource blocks from the part of the fifth subset subtracting the fourth subset, as the first subset of each of the other first cells, wherein the fifth subset is the part of the set of available resource blocks subtracting an intersection set of the interfering and interfered first cell resource block sets; selecting resource blocks from the fifth subset and then selecting the remaining resource blocks from the part of the set of available resource blocks subtracting the fifth subset, as the first subset of each of the other first cells.

[00126] In some example embodiments, the second determining subunit may be further configured to at least one of: if the second predetermined is less than or equal to the quantity of resource blocks in an intersection set of the interfering and interfered first cell resource block sets, selecting the second predetermined number of resource blocks from the intersection set as the second subset for each of the other first cells; if the second predetermined is less than or equal to the quantity of resource blocks in the interfering first cell resource block set, selecting resource blocks from the intersection set and then selecting the remaining resource blocks from the part of the interfering first cell resource block set subtracting the intersection set, as the second subset for each of the other first cells; if the second predetermined number is less than or equal to the quantity of resource blocks in a union set of the interfering and interfered first cell resource block sets, selecting resource blocks from the interfering first cell resource block set and then selecting the remaining resource blocks from a part of the union set subtracting the interfering first cell resource block set, as the second subset for each of the other first cells; selecting resource blocks from the union set and then selecting the remaining resource blocks from the part of the set of available resource blocks subtracting the union set, as the second subset for each of the other first cells, wherein resource blocks in the first subset of each of the other first cells are not selected when selecting resource blocks for the second subset of each of the other first cells.

[00127] In some example embodiments, the apparatus 600 may further comprise a second obtaining unit configured to obtain channel state information of the edge UE of the at least one first cell, wherein when determining the first subset for each of the at least one first cell, the first determining subunit or the second determining subunit is further configured to select resource blocks causing a channel quality of the edge UE larger than a third predetermined threshold from selectable resource blocks based on the channel state information of the edge UE.

[00128] In some example embodiments, the apparatus 600 may further comprise a power adjustment informing unit configured to inform each of the at least one first cell to increase a transmitting power corresponding to resource blocks in the first subset by a first power adjustment, wherein the first power adjustment is based, at least in part, on the total transmitting power of each of the at least one first cell, the first and second predetermined numbers.

[00129] In some example embodiments, the resource block informing unit 603 may be further configured to send to each of the at least one first cell a first bitmap indicating resource blocks contained in the first subset and a second bitmap indicating resource blocks contained in the second subset.

[00130] In some example embodiments, the resource block determining unit 602 may be further configured to determining periodically the first and second subsets for each of the at least one first cell, wherein the determined first and second subsets are informed to each of the at least one first cell by the resource block informing unit.

[00131] In some example embodiments, the apparatus 600 may be embodied in a base station of a macro cell or a small cell, and the first cell may be a macro cell or a small cell.

[00132] Figure 7 shows a block diagram of an apparatus 700 for interference coordination of edge UEs in accordance with another example embodiment of the present invention is shown. As shown, the apparatus 700 comprises an indicator receiving unit 701 configured to a first indicator and a second indicator from a second cell, wherein the first indicator indicating a first subset of resource blocks containing a first predetermined number of resource blocks to be used by an edge UE of the first cell, and the second indicator indicating a second subset of resource blocks containing a second predetermined number of resource blocks to be blanked by the first cell. The apparatus 700 also comprises a resource block scheduling unit 702 configured to schedule resource blocks for the edge UE in accordance with the first indicator. The apparatus 700 further comprises a resource block blanking unit 703 configured to blank at least one resource block in accordance with the second indicator.

[00133] In some example embodiments, the edge UE of the first cell has a signal quality lower than other UEs in the first cell and the signal quality is lower than a first predetermined threshold.

[00134] In some example embodiments, the apparatus 700 may further comprise a power increasing unit configured to increase the transmitting power corresponding to resource blocks scheduled for the edge UE by a first power adjustment.

[00135] In some example embodiments, the apparatus 700 may further comprise an information report unit configured to report information of the edge UE to the second cell, wherein the information comprising at least one of an identifier, channel state information and dominant interferer identifier of the edge UE, wherein the dominant interferer identifier identifies a cell having an interference level higher than a second predetermined threshold to the edge UE.

[00136] In some example embodiments, the apparatus 700 may be embodied in a base station of a small cell or a macro cell, and the second cell may be a small cell or a macro cell.

[00137] For the sake of clarity, some optional components of the apparatuses 600 and 700 are not shown in Figures 6 and 7. However, it should be appreciated that the features related to the coordinating cell as described above with reference to Figures 1-5 are all applicable to the apparatus 600 and those related to the coordinated cell as described above with reference to Figures 1 -5 are all applicable to the apparatus 700. Moreover, the components of the apparatuses 600 and 700 may be a hardware module or a software unit module. For example, in some embodiments, the apparatuses 600 and 700 may be implemented partially or completely with software and/or firmware, for example, implemented as a computer program product embodied in a computer readable medium. Alternatively or additionally, the apparatuses 600 and 700 may be implemented partially or completely based on hardware, for example, as an integrated circuit (IC), an application-specific integrated circuit (ASIC), a system on chip (SOC), a field programmable gate array (FPGA), and so forth. The scope of the present invention is not limited in this regard. [00138] Generally speaking, various example embodiments of the present invention may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of the example embodiments of the present invention are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it will be appreciated that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[00139] Additionally, various blocks shown in the flowcharts may be viewed as method steps, and/or as operations that result from operation of computer program code, and/or as a plurality of coupled logic circuit elements constructed to carry out the associated function(s). For example, embodiments of the present invention include a computer program product comprising a computer program tangibly embodied on a machine readable medium, the computer program containing program codes configured to carry out the methods as described above.

[00140] In the context of the disclosure, a machine readable medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine readable medium may be a machine readable signal medium or a machine readable storage medium. A machine readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the machine readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[00141] Computer program code for carrying out methods of the present invention may be written in any combination of one or more programming languages. These computer program codes may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor of the computer or other programmable data processing apparatus, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a computer, partly on the computer, as a stand-alone software package, partly on the computer and partly on a remote computer or entirely on the remote computer or server.

[00142] Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of any invention or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination.

[00143] Various modifications, adaptations to the foregoing example embodiments of this invention may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. Any and all modifications will still fall within the scope of the non-limiting and example embodiments of this invention. Furthermore, other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these embodiments of the invention pertain having the benefit of the teachings presented in the foregoing descriptions and the drawings.

[00144] It will be appreciated that the embodiments of the invention are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are used herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

WHAT IS CLAIMED IS:

1. A method for interference coordination of edge user equipment UE, comprising: obtaining a dominant interferer identifier of an edge UE in at least one first cell;

based, at least in part, on the obtained dominant interferer identifiers, determining a first subset of resource blocks for each of the at least one first cell from a set of available resource blocks, and determining a second subset of resource blocks for each of the at least one first cell from a part of the set of available resource blocks subtracting the first subset corresponding to each of the at least one first cell; and

informing the first and second subsets to each of the at least one first cell,

wherein the first subset contains a first predetermined number of resource blocks to be used by the edge UE of each of the at least one first cell, and the second subset contains a second predetermined number of resource blocks to be blanked by each of the at least one first cell.

2. The method according to Claim 1, wherein each of the at least one first cell has at least two active UEs.

3. The method according to Claim 1, wherein the edge UE of each of the at least one first cell has a signal quality lower than other UEs in the first cell and the signal quality is lower than a first predetermined threshold.

4. The method according to Claim 1, wherein the dominant interferer identifier of the edge UE in each of the at least one first cell identifies another first cell having an interference level higher than a second predetermined threshold to the edge UE in each of the at least one first cell.

5. The method according to Claim 1, wherein determining the first and second subsets of resource blocks for each of the at least one first cell comprising:

ranking the at least one first cell by a predetermined rule;

selecting the first predetermined number of resource blocks from the set of available resource blocks as the first subset for the first cell ranked the topmost, and selecting the second predetermined number of resource blocks from a part of the set of available resource blocks subtracting the first subset corresponding to the first cell ranked the topmost as the second subset for the first cell ranked the topmost; and

determining the first and second subsets for other first cells in the ranked order, and for each of the other first cells:

determining an interfering first cell resource block set and an interfered first cell resource block set corresponding to each of the other first cells from the determined first subsets, in accordance with the obtained dominant interferer identifiers,

determining the first subset for each of the other first cells, in accordance with a comparison of the first predetermined number with the quantities of resource blocks in the interfering and interfered first cell resource block sets, and

determining the second subset for each of the other first cells, in accordance with a comparison of the second predetermined number with the quantities of resource blocks in the interfering and interfered first cell resource block sets.

6. The method according to Claim 5, wherein the predetermined rule is based, at least in part, on a random order, or an order based on frequency of each of the at least one first cell being a dominant interfere of other first cells or on a total throughput of each of the at least one first cell.

7. The method according to Claim 5, wherein determining an interfering first cell resource block set and an interfered first cell resource block set corresponding to each of the other first cells from the determined first subsets, in accordance with the obtained dominant interferer identifiers, comprising:

searching, from the first cells the first subsets of which have been determined, whether there is a first cell identified by the dominant interferer identifier of each of the other first cells; determining the first subset of the searched first cell as the interfering first cell resource block set, or determining the interfering first cell resource block set as a null set if no first cell is searched;

searching, from the first cells the first subsets of which have been determined, whether there are first cells the dominant interferer identifiers of which identify each of the other first cells; and determining a union set of the first subsets of the searched first cells as the interfered first cell resource block set, or determined the interfered first cell resource block set as a null set if no first cell is searched.

8. The method according to Claim 5, wherein determining the first subset for each of the other first cells, in accordance with a comparison of the first predetermined number with the quantities of resource blocks in the interfering and interfered first cell resource block sets comprising at least one of:

if the first predetermined number is less than or equal to the quantity of resource blocks in a third subset, selecting the first predetermined number of resource blocks from the third subset as the first subset of each of the other first cells, wherein the third subset is a part of the set of available resource blocks subtracting the interfering and interfered first cell resource block sets;

if the first predetermined number is less than or equal to the quantity of resource blocks in a fourth subset, selecting resource blocks from the third subset and then selecting the remaining resource blocks from a part of the fourth subset subtracting the third subset, as the first subset of each of the other first cells, wherein the fourth subset is a part of the set of available resource blocks subtracting the interfering first cell resource block set;

if the first predetermined number is less than or equal to the quantity of resource blocks in a fifth subset, selecting resource blocks from the fourth subset and then selecting the remaining resource blocks from a part of the fifth subset subtracting the fourth subset, as the first subset of each of the other first cells, wherein the fifth subset is a part of the set of available resource blocks subtracting an intersection set of the interfering and interfered first cell resource block sets; and

selecting resource blocks from the fifth subset and then selecting the remaining resource blocks from a part of the set of available resource blocks subtracting the fifth subset, as the first subset of each of the other first cells.

9. The method according to Claim 5, wherein determining the second subset for each of the other first cells, in accordance with a comparison of the second predetermined number with the quantities of resource blocks in the interfering and interfered first cell resource block sets comprising at least one of: if the second predetermined is less than or equal to the quantity of resource blocks in an intersection set of the interfering and interfered first cell resource block sets, selecting the second predetermined number of resource blocks from the intersection set as the second subset for each of the other first cells;

if the second predetermined is less than or equal to the quantity of resource blocks in the interfering first cell resource block set, selecting resource blocks from the intersection set and then selecting the remaining resource blocks from a part of the interfering first cell resource block set subtracting the intersection set, as the second subset for each of the other first cells; if the second predetermined number is less than or equal to the quantity of resource blocks in a union set of the interfering and interfered first cell resource block sets, selecting resource blocks from the interfering first cell resource block set and then selecting the remaining resource blocks from a part of the union set subtracting the interfering first cell resource block set, as the second subset for each of the other first cells; and

selecting resource blocks from the union set and then selecting the remaining resource blocks from a part of the set of available resource blocks subtracting the union set, as the second subset for each of the other first cells,

wherein resource blocks in the first subset of each of the other first cells are not selected when selecting resource blocks for the second subset of each of the other first cells.

10. The method according to any of Claims 5 to 9, further comprising:

obtaining channel state information of the edge UE of the at least one first cell via a dual connectivity with the edge UE,

wherein when determining the first subset for each of the at least one first cell, resource blocks causing a channel quality of the edge UE larger than a third predetermined threshold from selectable resource blocks are selected based on the channel state information of the edge UE.

11. The method according to Claim 1, further comprising:

informing each of the at least one first cell to increase a transmitting power corresponding to resource blocks in the first subset by a first power adjustment,

wherein the first power adjustment is based, at least in part, on the total transmitting power of each of the at least one first cell, the first and second predetermined numbers.

12. The method according to Claim 1, wherein informing the first and second subsets to each of the at least one first cell comprising:

sending to each of the at least one first cell a first bitmap indicating resource blocks contained in the first subset and a second bitmap indicating resource blocks contained in the second subset.

13. The method according to Claim 1, further comprising:

determining periodically the first and second subsets for each of the at least one first cell and then informing the determined first and second subsets to each of the at least one first cell.

14. A method for interference coordination of edge user equipment UE, comprising: a base station of a first cell receiving a first indicator and a second indicator from a second cell, wherein the first indicator indicating a first subset of resource blocks containing a first predetermined number of resource blocks to be used by an edge UE of the first cell, and the second indicator indicating a second subset of resource blocks containing a second predetermined number of resource blocks to be blanked by the first cell;

scheduling resource blocks for the edge UE in accordance with the first indicator; and blanking at least one resource block in accordance with the second indicator.

15. The method according to Claim 14, wherein the edge UE of the first cell has a signal quality lower than other UEs in the first cell and the signal quality is lower than a first predetermined threshold.

16. The method according to Claim 14, further comprising:

increasing a transmitting power corresponding to resource blocks scheduled for the edge UE by a first power adjustment.

17. The method according to any of Claims 14 to 16, further comprising:

reporting information of the edge UE to the second cell via a backhaul link,

wherein the information comprising at least one of an identifier, channel state information and dominant interferer identifier of the edge UE, and wherein the dominant interferer identifier identifies a cell having an interference level higher than a second predetermined threshold to the edge UE.

18. An apparatus for interference coordination of edge user equipment UE, comprising: a first obtaining unit configured to obtain a dominant interferer identifier of an edge UE in at least one first cell;

a resource block determining unit configured to determine a first subset of resource blocks for each of the at least one first cell from a set of available resource blocks, and determining a second subset of resource blocks for each of the at least one first cell from a part of the set of available resource blocks subtracting the first subset corresponding to each of the at least one first cell, based, at least in part, on the obtained dominant interferer identifiers; and a resource block informing unit configured to inform the first and second subsets to each of the at least one first cell,

19. The apparatus according to Claim 18, wherein each of the at least one first cell has at least two active UEs.

20. The apparatus according to Claim 18, wherein the edge UE of each of the at least one first cell has a signal quality lower than other UEs in the first cell and the signal quality is lower than a first predetermined threshold.

21. The apparatus according to Claim 18, wherein the dominant interferer identifier of the edge UE in each of the at least one first cell identifies another first cell having an interference level higher than a second predetermined threshold to the edge UE in each of the at least one first cell.

22. The apparatus according to Claim 18, wherein the resource block determining unit comprising:

a ranking subunit configured to rank the at least one first cell by a predetermined rule; a first determining subunit configured to select the first predetermined number of resource blocks from the set of available resource blocks as the first subset for the first cell ranked the topmost, and selecting the second predetermined number of resource blocks from a part of the set of available resource blocks subtracting the first subset corresponding to the first cell ranked the topmost as the second subset for the first cell ranked the topmost; and

a second determining subunit configured to determine the first and second subsets for other first cells in the ranked order, and for each of the other first cells, the second determining subunit is further configured to:

determine an interfering first cell resource block set and an interfered first cell resource block set corresponding to each of the other first cells from the determined first subsets, in accordance with the obtained dominant interferer identifiers,

determine the first subset for each of the other first cells, in accordance with a comparison of the first predetermined number with the quantities of resource blocks in the interfering and interfered first cell resource block sets, and

determine the second subset for each of the other first cells, in accordance with a comparison of the second predetermined number with the quantities of resource blocks in the interfering and interfered first cell resource block sets.

23. The apparatus according to Claim 22, wherein the predetermined rule is based, at least in part, on a random order, or an order based on frequency of each of the at least one first cell being a dominant interfere of other first cells or on a total throughput of each of the at least one first cell.

24. The apparatus according to Claim 22, wherein the second determining subunit is further configured to:

search, from the first cells the first subsets of which have been determined, whether there is a first cell identified by the dominant interferer identifier of each of the other first cells; determine the first subset of the searched first cell as the interfering first cell resource block set, or determining the interfering first cell resource block set as a null set if no first cell is searched;

search, from the first cells the first subsets of which have been determined, whether there are first cells the dominant interferer identifiers of which identify each of the other first cells; and determine a union set of the first subsets of the searched first cells as the interfered first cell resource block set, or determined the interfered first cell resource block set as a null set if no first cell is searched.

25. The apparatus according to Claim 22, wherein the second determining subunit is further configured to at least one of:

if the first predetermined number is less than or equal to the quantity of resource blocks in a fifth subset, selecting resource blocks from the fourth subset and then selecting the remaining resource blocks from the part of the fifth subset subtracting the fourth subset, as the first subset of each of the other first cells, wherein the fifth subset is the part of the set of available resource blocks subtracting an intersection set of the interfering and interfered first cell resource block sets; and

26. The apparatus according to Claim 22, wherein the second determining subunit is further configured to at least one of:

if the second predetermined is less than or equal to the quantity of resource blocks in an intersection set of the interfering and interfered first cell resource block sets, selecting the second predetermined number of resource blocks from the intersection set as the second subset for each of the other first cells; if the second predetermined is less than or equal to the quantity of resource blocks in the interfering first cell resource block set, selecting resource blocks from the intersection set and then selecting the remaining resource blocks from a part of the interfering first cell resource block set subtracting the intersection set, as the second subset for each of the other first cells; if the second predetermined number is less than or equal to the quantity of resource blocks in a union set of the interfering and interfered first cell resource block sets, selecting resource blocks from the interfering first cell resource block set and then selecting the remaining resource blocks from a part of the union set subtracting the interfering first cell resource block set, as the second subset for each of the other first cells; and

27. The apparatus according to any of Claims 22 to 26, further comprising:

a second obtaining unit configured to obtain channel state information of the edge UE of the at least one first cell via a dual connectivity with the edge UE,

wherein when determining the first subset for each of the at least one first cell, the first determining subunit or the second determining subunit is further configured to select resource blocks causing a channel quality of the edge UE larger than a third predetermined threshold from selectable resource blocks based on the channel state information of the edge UE.

28. The apparatus according to Claim 18, further comprising:

a power adjustment informing unit configured to inform each of the at least one first cell to increase a transmitting power corresponding to resource blocks in the first subset by a first power adjustment,

29. The apparatus according to Claim 18, wherein the resource block informing unit is further configured to send to each of the at least one first cell a first bitmap indicating resource blocks contained in the first subset and a second bitmap indicating resource blocks contained in the second subset.

30. The apparatus according to Claim 18, wherein the resource block determining unit is further configured to determining periodically the first and second subsets for each of the at least one first cell, and wherein the determined first and second subsets are informed to each of the at least one first cell by the resource block informing unit.

31. The apparatus according to Claim 18, wherein the apparatus is embodied in a base station of a macro cell or a small cell, and the first cell is a macro cell or a small cell.

32. An apparatus for interference coordination of edge user equipment UE, comprising: an indicator receiving unit configured to a first indicator and a second indicator from a second cell, wherein the first indicator indicating a first subset of resource blocks containing a first predetermined number of resource blocks to be used by an edge UE of the first cell, and the second indicator indicating a second subset of resource blocks containing a second predetermined number of resource blocks to be blanked by the first cell;

a resource block scheduling unit configured to schedule resource blocks for the edge UE in accordance with the first indicator; and

a resource block blanking unit configured to blank at least one resource block in accordance with the second indicator.

33. The apparatus according to Claim 32, wherein the edge UE of the first cell has a signal quality lower than other UEs in the first cell and the signal quality is lower than a first predetermined threshold.

34. The apparatus according to Claim 32, further comprising:

a power increasing unit configured to increase a transmitting power corresponding to resource blocks scheduled for the edge UE by a first power adjustment.

35. The apparatus according to any of Claims 32 to 34, further comprising:

an information report unit configured to report information of the edge UE to the second cell via a backhaul link, wherein the information comprising at least one of an identifier, channel state information and dominant interferer identifier of the edge UE, and

wherein the dominant interferer identifier identifies a cell having an interference level higher than a second predetermined threshold to the edge UE.

36. The apparatus according to Claim 32, wherein the apparatus is embodied in a base station of a small cell or a macro cell, and the second cell is a small cell or a macro cell.