WO2013170471A1

WO2013170471A1 - Mechanism for controlling communications using resource co-scheduling in inter-cell interference scenario

Info

Publication number: WO2013170471A1
Application number: PCT/CN2012/075671
Authority: WO
Inventors: Lili Zhang; Haiming Wang; Tero Henttonen
Original assignee: Renesas Mobile Corporation
Priority date: 2012-05-17
Filing date: 2012-05-17
Publication date: 2013-11-21

Abstract

There is proposed a mechanism for controlling communications in communication networks using a resource co-scheduling procedure for handling inter-cell interferences. Communication information providing information related to an access to a first cell is provided by a first (pico) cell to UEs of the first cell and to a second (macro) cell. The pico UEs monitor for communications from UEs of the second (macro) cell and measure an interference level caused thereby. In the pico cell, an inter-cell interference matrix is generated from the reported interferences and provided to the second cell. The second cell conducts a co-scheduling of resources on the basis of the information contained in the inter-cell interference matrix.

Description

MECHANISM FOR CONTROLLING COMMUNICATIONS USING RESOURCE CO- SCHEDULING IN INTER-CELL INTERFERENCE SCENARIO

DESCRIPTION

BACKGROUND OF THE INVENTION

Field of the invention

The present invention relates to a mechanism for controlling communications in communication networks using a resource co-scheduling procedure for handling inter-cell interferences. In particular, the present invention is directed to apparatuses, methods and computer program products by means of which the inter-cell interferences caused between cells of communication networks, in particular in a heterogeneous communication network environment, are avoided by using a co-scheduling procedure of resources to be allocated to respective communications in the cells.

Related background Art

Prior art which is related to this technical field can e.g. be found in technical specifications according to 3GPP TR 36.213 (e.g. version 10.5.0), 3GPP TR 36.814 (e.g. version 9.0.0).

The following meanings for the abbreviations used in this specification apply:

BS : base station

CA: carrier aggregation

CPU : central processing unit

DL: downlink

eNB : evolved node B

HetNet: heterogeneous network

ICIC: inter-cell interference coordination ICIM : inter-cell interference matrix

ID: identification

IE : information element

LTE: Long Term Evolution

LTE-A: LTE Advanced

MeNB: macro eNB

MUE: macro UE

PeNB: pico eNB

PRACH : physical random access channel

P B: physical resource block

PUE pico UE

QoS: quality of service

RRM : radio resource management

SFR: soft frequency reuse

SMUE suspected MUE

SPS : semi-persistent scheduling

SRS: sounding reference signal

SUE suspected UE

TDD : time division multiplex

UE: user equipment

UL: uplink

In the last years, an increasing extension of communication networks, e.g. of wire based communication networks, such as the Integrated Services Digital Network (ISDN), DSL, or wireless communication networks, such as the cdma2000 (code division multiple access) system, cellular 3rd generation (3G) communication networks like the Universal Mobile Telecommunications System (UMTS), enhanced communication networks based e.g. on LTE, cellular 2nd generation (2G) communication networks like the Global System for Mobile communications (GSM), the General Packet Radio System (GPRS), the Enhanced Data Rates for Global Evolutions (EDGE), or other wireless communication system, such as the Wireless Local Area Network (WLAN), Bluetooth or Worldwide Interoperability for Microwave Access (WiMAX), took place all over the world. Various organizations, such as the 3rd Generation Partnership Project (3GPP), Telecoms & Internet converged Services & Protocols for Advanced Networks (TISPAN), the International Telecommunication Union (ITU), 3rd Generation Partnership Project 2 (3GPP2), Internet Engineering Task Force (IETF), the IEEE (Institute of Electrical and Electronics Engineers), the WiMAX Forum and the like are working on standards for telecommunication network and access environments.

Key issues for the configuration of communication network are, for example, minimization of interferences or their impact on communications and optimization of resource usage.

In new communication networks, such as those being based on LTE specifications according to release 11, several proposals are examined in order to achieve the above goals. For example, according to one proposal, it is studied how further enhancements to LTE TDD for DL-UL interference management and traffic adaptation can be achieved in order to allow for asymmetric UL-DL allocations. Asymmetric UL-DL allocations refer to, for example, that a DL and UL coverage in a cell, such as a small or pico cell, is unbalanced (e.g. UL coverage is greater). For example, different TDD time configuration modes are applied for different cells, such as a macro cell and a small cell in a HetNet configuration, so as to adapt to various traffic load scenarios. By means of this, improved spectral utilization and power saving is achievable. In order to apply different TDD UL-DL configurations in different cells, e.g. for some multi-ce!i scenarios, it is required to provide a suitable interference control.

However, with flexible TDD time configuration enabled in HetNets, new interference problems may arise. Specifically, interferences in DL->UL or UL->DL direction which are introduced between the macro cell and the small cell, or between adjacent small cells etc., are to be considered. With the usage of current mechanisms, such as ICIC for HetlMet, or enhanced ICIC and multiple carrier based ICIC, the above mentioned interference cases can not be solved properly.

SUMMARY OF THE INVENTION Examples of embodiments of the invention provide an apparatus, method and computer program product by means of which an improved communication control mechanism is achieved. In particular, according to examples of embodiments of the present invention, apparatuses, methods and computer program products are provided by means of which inter-cell

Interferences caused between cells of communication networks, in particular in a heterogeneous communication network environment, are avoided and a resource coordination scheme is implemented which us useful for reducing the interference.

This is achieved by the measures defined in the attached claims.

According to an example of an embodiment of the proposed solution, there is provided, for example, an apparatus comprising at least one processor; and at least one memory including computer program code; wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to perform a communication information providing function configured to provide communication information related to an access to a first cell of a communication network by causing transmission of the communication information to selected communication elements connected to the first cell and to a communication network control element of a second cell of the communication network, an interference report processing function configured to receive and process interference reports from the selected communication elements, wherein the interference reports indicate an interference level information related to a communication conducted on resources indicated in the communication information, an inter-cell interference matrix generation function configured to generate, on the basis of the interference reports, an inter-cell interference matrix indicating information of interferences caused in the first cell by a transmission of the second cell, and an interference feedback function configured to cause transmission of interference feedback information to the communication network control element of the second cell, the interference feedback information comprising an identification of interference sources and the inter-cell interference matrix. Furthermore, according to an example of an embodiment of the proposed solution, there is provided, for example, a method comprising providing communication information related to an access to a first eel! of a communication network by causing transmission of the communication information to selected communication elements connected to the first cell and to a communication network control element of a second cell of the communication network, receiving and processing interference reports from the selected communication elements, wherein the interference reports indicate an interference level information related to a communication conducted on resources indicated in the communication information, generating, on the basis of the interference reports, an inter-cell interference matrix indicating information of interferences caused in the first cell by a transmission of the second cell, and causing transmission of interference feedback information to the communication network control element of the second cell, the interference feedback information comprising an identification of interference sources and the inter-cell interference matrix.

In addition, according to another example of an embodiment of the proposed solution, there is provided, for example an apparatus comprising at least one processor; and at least one memory including computer program code; wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to perform a communication information processing function configured to process communication information received from a communication network control element of a first cell of a communication network and being related to an access to the first cell by at least one communication element of a second cell of the communication network, a transmission monitoring function configured to monitor for transmissions on resources indicated in the communication information, an interference determining function configured to determine an interference level caused by a communication conducted on the resources indicated in the communication information, and to identify an interfering source on the basis of the communication information, and an interference report transmission function configured to cause transmission of an interference report to the communication network control element of the first celi, wherein the interference report indicates the determined interference level and the identified interfering source.

Furthermore, according to another example of an embodiment of the proposed solution, there is provided, for example, a method comprising processing communication information received from a communication network control element of a first cell of a communication network and being related to an access to the first cell by at least one communication element of a second cell of the communication network, monitoring for transmissions on resources indicated in the communication information, determining an interference level caused by a communication conducted on the resources indicated in the communication information, identifying an interfering source on the basis of the communication information, and causing transmission of an interference report to the communication network control element of the first cell, wherein the interference report indicates the determined interference level and the identified interfering source.

In addition, according to another example of an embodiment of the proposed solution, there is provided, for example, an apparatus comprising at least one processor; and at least one memory including computer program code; wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to perform a communication information processing function configured to process communication information related to an access to a first cell of a communication network and provided by a communication network control element of the first cell of the communication network, an access initiating function configured to initiate an access of a selected communication element of the second cell to the first cell by causing transmission of the communication information to the selected communication element, an interference feedback processing function configured to receive and process interference feedback information from the communication network control element of the first cell, the interference feedback information comprising an identification of interference sources and an inter-cell interference matrix indicating information of interferences caused in the first cell by a transmission of the selected communication element, and a co-scheduling processing function configured to conduct a co-scheduling of resources for communication elements communicating in the first and second cells on the basis of the interference feedback information.

Furthermore, according to an example of an embodiment of the proposed solution, there is provided, for example, a method comprising processing communication information related to an access to a first cell of a communication network and provided by a communication network control element of the first cell of the communication network, initiating an access of a selected communication element of the second cell to the first cell by causing transmission of the communication information to the selected communication element, receiving and processing interference feedback information from the communication network control element of the first cell, the interference feedback information comprising an identification of interference sources and an inter-cell interference matrix indicating information of interferences caused in the first cell by a transmission of the selected communication element, and conducting a co-scheduling of resources for communication elements communicating in the first and second cells on the basis of the interference feedback information.

In addition, according to examples of the proposed solution, there is provided, for example, a computer program product for a computer, comprising software code portions for performing the steps of the above defined methods, when said product is run on the computer. The computer program product may comprise a computer-readable medium on which said software code portions are stored. Furthermore, the computer program product may be directly loadable into the internal memory of the computer and/or transmittable via a network by means of at least one of upload, download and push procedures.

By virtue of the proposed solutions, it is possible to provide a mechanism for controlling communications using a resource co-scheduling procedure for handling inter-cell interferences. Specifically, it is possible, for example when a flexible TDD configuration is used in communication networks, to conduct a co-scheduling procedure for the communication resources in such a manner that the interference which could be caused by the flexible TDD configuration is reduced or avoided. For example, by employing a suitable grouping of UEs of adjacent or overlapping cells, such as a macro cell and a pico cell, e.g. in inter-cell mapped group and unmapped group, and by applying co-scheduling criteria for scheduling the resources according to examples of embodiments of the invention, inter-cell scheduling coordination is achieved to reduce e.g. the UL->DL interference effectively. Moreover, it is possible to consider the impact of the shifting of an UL uplink interference area, so that an unnecessary scheduling restriction of some innocent UEs of e.g. the macro cell or an incorrect identification of some actually interfering macro UEs is avoided. In addition, by generating and signaling interference related information, such as ICIM piggybacked with the uplink interfering source identification, it is possible to facilitate that an inter-cell group with tolerable interference can be scheduled simultaneously for different DL/UL transmission, so that the spectral utilization efficiency is improved. Furthermore, it is possible to provide a more detailed set of information by means of signaling the ICIM, e.g. by an indication of subframe or frequency subband or carrier level, compared with a local RRM signaling, so that an improved processing and resource scheduling in possible. Moreover, a measurement report overhead for the inter-cell interference detection e.g. from a UE to a elMB can be controlled and kept at a proper level by setting an appropriate interference threshold which represent a trigger event for sending an indication of e.g. the most interference sensitive SUEs. In addition, by providing location information of a UE, the establishment of the groups can be supported, which allows to further decrease the requirement of sending measurement reports, which in turn helps to alleviate the overhead. The above and still further objects, features and advantages of the invention will become more apparent upon referring to the description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a diagram illustrating a communication network structure with a HetNet configuration in which examples of embodiments of the invention are applicable.

Fig. 2 shows a diagram illustrating an enlarged view of the communication network structure shown in Fig, 1 wherein further details are depicted.

Fig. 3 shows a signaling diagram illustrating a signaling exchange between network elements of the communication network structure shown in Figs. 1 and 2 according to examples of embodiments of the invention.

Fig . 4 shows a diagram illustrating an interference determination procedure in network elements of the communication network structure shown in Figs. 1 and 2 according to examples of embodiments of the invention.

Fig. 5 shows a diagram illustrating an ICIM generation in a communication network control element of the communication network structure shown in Figs. 1 and 2 according to examples of embodiments of the invention.

Figs. 6a and 6b show diagrams illustrating a spectral utilization in a communication network structure shown in Figs. 1 and 2 according to a conventional example and according to examples of embodiments of the invention.

Fig. 7 shows a flowchart illustrating an example of a communication control procedure conducted by a communication network control element according to examples of embodiments of the invention.

Fig. 8 shows a flowchart illustrating an example of a communication control procedure conducted by a communication element according to examples of embodiments of the invention. Fig. 9 shows a flowchart illustrating an example of a communication control procedure conducted by a communication network control element according to examples of embodiments of the invention.

Fig. 10 shows a block circuit diagram of a communication network control element including processing portions conducting functions according to examples of embodiments of the invention.

Fig. 11 shows a block circuit diagram of a communication element including processing portions conducting functions according to examples of embodiments of the invention.

Fig. 12 shows a block circuit diagram of a communication network control element including processing portions conducting functions according to examples of embodiments of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

In the following, examples and embodiments of the present invention are described with reference to the drawings. For illustrating the present invention, the examples and embodiments wi!l be described in connection with a cellular communication network based on a 3GPP LTE or LTE-A system wherein a heterogeneous network configuration comprising a macro cell controlled by a communication network control element, such as a MeNB, and one or more small cells, also referred to hereinafter as pico cells, located in the macro cell area and controlled by a communication network control element such as a PeNB is employed. However, it is to be noted that the present invention is not limited to an application using such types of communication systems, but is also applicable in other types of communication systems and the like. For example, the cells may be of the same type, such as two or more overlapping macro or pico cells, respectively. A basic system architecture of a communication network where examples of embodiments of the invention are applicable may comprise a commonly known architecture of one or more communication systems comprising a wired or wireless access network subsystem and a core network. Such an architecture may comprise one or more access network control elements, radio access network elements, access service network gateways or base transceiver stations, such as a base station (BS) or e B, which control a coverage area also referred to as a cell and with which a communication element or terminal device such as a UE or another device having a similar function, such as a modem chipset, a chip, a module etc., which can also be part of a UE or attached as a separate element to a UE, or the like, is capable to communicate via one or more channels for transmitting several types of data. Furthermore, core network elements such as gateway network elements, policy and charging control network elements, mobility management entities and the like may be comprised.

The general functions and interconnections of the described elements, which also depend on the actual network type, are known to those skilled in the art and described in corresponding specifications, so that a detailed description thereof is omitted herein. However, it is to be noted that several additional network elements and signaling links may be employed for a communication to or from a communication element like a UE or a communication network control element like an eNB etc., besides those described in detail herein below.

Furthermore, the described network elements, such as communication elements like UEs, communication network control elements like BSs, eNBs (MeNB, PeNB), and the like, as well as corresponding functions as described herein may be implemented by software, e.g. by a computer program product for a computer, and/or by hardware. In any case, for executing their respective functions and/or algorithms, correspondingly used devices, nodes or network elements may comprise several means and components (not shown) which are required for control, processing and communication/signaling functionality. Such means may comprise, for example, one or more processor units including one or more processing portions for executing instructions, programs and for processing data, memory means for storing instructions, programs and data, for serving as a work area of the processor or processing portion and the like (e.g. ROM, RAM, EEPROM, and the like), input means for inputting data and instructions by software (e.g. floppy disc, CD-ROM, EEPROM, and the like), user interface means for providing monitor and manipulation possibilities to a user (e.g. a screen, a keyboard and the like), interface means for establishing links and/or connections under the control of the processor unit or portion (e.g. wired and wireless interface means, an antenna, etc.) and the like. It is to be noted that in the present specification processing portions should not be only considered to represent physical portions of one or more processors, but may also be considered as a logical division of the referred processing tasks performed by one or more processors.

Fig. 1 shows a diagram illustrating a communication network structure with a HetNet configuration in which examples of embodiments of the invention are applicable. In the described communication network, a HetNet with a deployment of a macro cell 200 controlled by a MeNB 20 and (at least one) small cell such as a pico cefl, a relay cell, a femto cell or local area cell (referred to hereinafter as pico cell) whose DL coverage area is indicated by a dotted circle in Fig. 1 around the controlling network element PeNB 30 is provided. According to examples of embodiments of the invention, the different link directions in the HetNet are configured due to flexible a time configuration mode (flexible TDD configuration mode).

Connected to each of the cells (macro and pico cells), i.e. to the respective communication network control element MeNB 20 and PeNB 30, one or more terminal devices or UEs are shown. The UEs connected to the MeNB 20 are referred to as MUE 40 wherein in the example shown in Fig 1 four MUEs are assumed, (i.e. MUE1 to MUE4). The UEs connected to the PeNB 30 are referred to PUE 10. Regarding the interfering communications in a network configuration as shown in Fig. 1, there are two different cases. In the first case the DL transmission is assumed to occur in the small cell and the UL transmission is assumed to occur in the macro cell. A second case is vice versa. Due to this, inter-cell UL->DL interference problems may arise, wherein in the following the first case is assumed to happen in the network shown in Fig. 1.

In this first case communication, a MUE that is farther away from the pico cell (such as MUE 2 in Fig.1) can cause the same level of UL interference to the pico cell as a MUE close to the pico cell (such as MUE 1 in Fig. l) ,

Basically, in order to ensure that the DL data reception of all the PUEs is satisfied, it is to be avoided that the UL interfering source of this pico ceil is scheduled on the same resource, or that a certain transmission power for some involved resource is exceeded. Hence, the transmission of the interfering source in the aggressor cell and the interfered UE in the victim cell is to be coordinated.

It is to be noted that an aggressor cell may be a macro cell or a pico cell when muftiple pico cells are overlapping to each other. In the following, it is assumed that the macro cell 200 represents the aggressor cell to the victim pico cell, as an example.

As shown in Fig. 1, an UL interference area, where MUEs cause UL interference to the pico cell, can be depicted by an area encircled by a dashed line. The UL interference area can be basically modeled by a geometric area where the difference of the path loss is larger than a predefined threshold, which can be further translated to the distance ratio is larger than a threshold. By known mathematical methods, it is known that the UL interference area can be normally depicted as a circled area as shown in Fig. 1, the center of which is on an extension line from the MeNB 20 to the PeNB 30. It is to be noted that the UL interference area can be much larger than PeNB's coverage area, due to the UL/DL asymmetry. Furthermore, with a new link with different link direction enabled in the pico cell, various reception points may cause the UL interference area being expanded, depending on the location of PUEs relative to the pico elMB. Therefore, it has to be ensured that accomplish an exact identification of interfering sources even in case of a shifting of the UL interference area is ensured which is not possible by using conventional High Interference Indicator (HII) and Overload Indicator (01) exchanged between base stations since some innocent MUEs may be restricted while some actually interfering MUEs may not be identified correctly.

Fig. 2 shows a diagram illustrating an enlarged view of the communication network structure shown in Fig. 1 wherein further details are depicted. Specifically, as can be seen in Fig. 2, there are four PUE 10 located in the pico ceil, i.e. PUEl to PUE 4. Due to their relative close location, PUEl and PUE3 are forming a PUE group 1, while PUE2 and PUE4 are forming a PUE group 2. However, it is also possible to group the PUEs on the basis of another criteria besides the location, for example on the basis of used resources or the like.

Furthermore, as shown in Fig. 2, details of the UL interference scenario for the above mentioned first case are depicted. In detail, the shifting of UL interference areas is shown.

As already indicated in Fig. 1, the dashed encirclement shows the UL interference area to the PeNB 30. Furthermore, as shown by a single- dotted dashed encirclement, an UL interference area to a PUE (PUEl and/or PUE group 1) is indicated. Moreover, as shown by a double-dotted dashed encirclement, an UL interference area to PUE2 (PUE 2 and/or PUE group 2) is shown. In the following, it is assumed that the UL interference area to PUE group 1 is the union of that to both the PeNB 30 and e.g. PUEl, while the UL interference area to PUE group 2 is the union of that to both PeNB 30 and PUE2. As further illustrated in Fig. 2, the MUE1 is in the UL interfering area of PUE group 1, but it is outside of the UL interfering area of PeNB 30. Furthermore, the UE2 is assumed to be in the UL interfering area of PeNB 30 but outside of the UL interfering area of PUE group 2. The MUE3 is assumed to be in the UL interfering area of PeNB 30 but outside of that of PUE group 1. The MUE4 is assumed to be in the UL interfering area of PUE group 2 but outside of that of PeNB 30.

According to a comparative example, in order to identify an interfering MUE, the MeNB selects suspected MUEs (SMUEs) to perform a non-contention based Random Access procedure using PRACH resources and preambles or to send a sounding reference signal (SRS) with SRS patterns known to the MeNB and the PeNB beforehand. The PeNB then detects the preamble/SRS transmissions and forwards the received preambles/SRS pattern to the MeNB, as well as an indication of the received signal strength of the preambles/SRS. The MeNB is able to identify the MUEs by using the received preambles/SRS pattern based on associations established beforehand, and the MeNB is able to identify the interfering MUE(s) based on the received signal strength information provided by the PeNB,

According to examples of embodiments of the invention, a communication control mechanism is provided in which the UL-> DL interference is reduced by using a resource scheduling coordination. Specifically, according to examples of embodiments of the invention, an inter-cell co-scheduling scheme is proposed accompanying the uplink interfering source identification, wherein in addition the spectral utilization can be maximized.

According to examples of embodiments of the invention, the inter-cell coordination of resource scheduling is employed to effectively reduce the UL->DL interference and to maximize the spectral utilization. This can be used in particular in cases where the flexible TDD subframe configuration in the HetNet is employed, since inter-cell UEs or UE groups having a tolerable interference to each other can be scheduled simultaneously on the same resources for different DL/UL transmission. In the following, according to examples of embodiments of the invention, a communication control mechanism is described where an inter-cell co- scheduling scheme is used to reduce the UL->DL interference when the flexible TDD time configuration mode is enabled in the HetNet. In particular, the co-scheduling scheme is implemented on the basis of establishing an inter-cell UE group which is established together with an identification of uplink interfering sources.

According to examples of embodiments of the invention, scheduling information concerning a UE group is piggybacked with the notification of UL interfering sources so as to facilitate the coordination in a control element. According to further examples of embodiments of the invention, the scheduling of the UL interfering source is conditioned on the resulting interference to the established groups in neighboring cells and vice versa.

Thus, according to examples of embodiments of the invention, an efficient inter-cell group establish and coordination scheme is provided that allows a communication network control element, such as an eNB, to perform an effective resource utilization and to deal with the UL-> DL interferences.

That is, according to examples of embodiments of the invention, inter-cell mapped group and inter-cell unmapped groups are set up. Basically, as described with regard to Fig. 2, a UE group is of the feature that UEs belonging to it are more concentrated rather than distributed, alternatively are close to each other in a specific area (such as PUE groups 1 and 2) . On the other hand, the inter-cell mapped group and inter-cell unmapped group which are to be set up are of another feature. Specifically, the inter-cell mapped group denotes UEs or UE groups that are far away from each other and have hence with a tolerable interference (i.e. an interference below or equal to a threshold for a tolerable interference), while Es or UE groups that creates a significant interference to each other (i.e. an interference greater than the threshold for the tolerable interference) are in the inter-cell unmapped group.

According to examples of embodiments of the invention, as a new information element used for indicating the interference situation in the pico cell to the MeNB, an ICIM is generated and transmitted via a suitable interface among the adjacent e Bs. The ICIM includes, for example, the group ID, to be scheduled time/frequency resource, sensed interference level, and the related information of the suspected uplink interfering source.

Furthermore, according to examples of embodiments of the invention, on the basis of the ICIM information, the adjacent eNBs conduct a co- scheduling of resources for interference avoidance. Specifically, the UL interfering source (MUE) is identified exactly and a utilization of the same resource in UE communications which are identified to interfere each other is avoided. Thus, it is possible to implement an interference aware scheduling and to improve the utilization of spectral resource.

According to examples of embodiments of the invention, for performing the co-scheduling, specific co-scheduling criteria are defined. These criteria comprise, according to examples of embodiments of the invention, that UEs belonging to the same inter-cell mapped group may be scheduled in the same resource, for example in terms of the chosen subframe, or carrier or partitioned frequency subbands or PRB, i.e., in the sense of a group scheduling for the same time/frequency resource. On the other hand, the criteria comprise also that UEs belonging to the same inter-cell unmapped group shall be scheduled in separate time/frequency resources so as to reduce interference. When using these criteria in the network structure depicted in Fig. 2, for example, as a result, the MUE1 can utilize the same resources (subframe, frequency band etc.) like that used for the PUE group 2, for example. Furthermore, the MUE4 can utilize the same resources (subframe, frequency band etc.) like that used for the PUE group 1, for example.

The inter-cell UE interference matrix or ICIM is used, according to examples of embodiments of the invention, to indicate interference information indicating that a selected UE in a classified group of a victim cell (such as the pico cell in Figs. 1 and 2, for example PUE 1) suffers from a suspected UL interfering source of an aggressor cell (such as the macro cell in Figs. 1 and 2, for example by one of the MUEs), and to indicate to be scheduled resources of the corresponding group (i.e. resources allocated by e.g. the PeNB to the respective PUE). For example, according to examples of embodiments of the invention, the ICIM contains the group ID, to be scheduled time/ frequency resources, a sensed interference level, and the related information of the suspected UL interfering source. The indicated time resources may be a specific subframe or some sort of subframe pattern allocated to the respective PUE. Furthermore, the indicated frequency resources may be the PRBs, the partitioned subbands, or a carrier allocated to the respective PUE.

It is to be noted that according to examples of embodiments of the invention the ICIM is semi-statically exchanged over an interface between adjacent eNBs, for example a so-called X2 interface, or via an air interface.

Fig. 3 shows a signaling diagram illustrating a signaling exchange between network elements of the communication network structure shown in Figs. 1 and 2 according to examples of embodiments of the invention. Specifically, Fig. 3 shows a procedure used for inter-cell group establishment and co- scheduling.

As indicated above, it is assumed that the macro cell, i.e. MeNB 20 represents the aggressor cell and the pico cell, i.e. PeNB 30 represents the victim cell.

In case a flexible time configuration mode is configured with simultaneous UL/DL transmission in the network shown in Fig. 2, the PeIMB 30 indicates communication information such as preamble/SRS pattern configuration information to the MeNB 20 in step S10 and to selected PUEs in step S15. That is, when the PeNB 30 provides multiple contention free preamble/SRS pattern to MeNB 20, the PeNB 30 informs also the selected PUEs to detect, for example simultaneously with PeNB 30, a corresponding detection of communications based on the indicated information. As a selection criteria for selecting the respective PUEs, according to examples of embodiments of the invention, the PeNB 30 selects only those PUEs for which such detection procedure will be applied which have, for example, a potentially heavy traffic load, and/or PUEs located at the edge of the cell or of a specific group.

In step S20, the MeNB 20 selects MUEs which are suspected to cause interference in the pico cell, also referred to as SUEs or SMUEs. To these SMUEs 40, the MeNB 20 assigns and sends (step S30) communication information (preamble/SRS pattern) from the communication information received from the PeNB 30.

When the SMUE (e.g. UE1) performs the PRACH/channel sounding transmission, it uses the assigned preamble/SRS pattern in a signaling to the PeNB 30 (e.g. for a corresponding access attempt), as indicated in step S40.

The selected PUEs monitor for transmissions by using the preamble/SRS pattern received in step S15 and detect in step S50 a respective signal strength on a specific carrier which is monitored for the corresponding transmission. Based on the detection, the PUEs deduce the interfering SMUE and a sensed interference level.

In step S60, the selected PUEs report the sensed interference level to the PeNB 30 by a corresponding interference report. That is, when the selected PUEs have sensed the interference signal strength, they establish for example an interference level table locally and report it to the PeNB 30.

When receiving the interference reports from the selected PUEs, in step S70, the PeNB 30 establishes or generates the ICIM on the basis thereof,

According to examples of embodiments of the invention, there are different ways for the forming of the ICIM in order to accommodate different coordination techniques. For example, the PUE group member have a common feature concerning a level of interference of some SUEs, i.e. a group with less interference from some SUEs or a group with highest interference sensitivity to these SUEs. Alternatively or additionally, in order to maximize a frequency diversity gain, the group members are allocated in a certain PRB, frequency subband or carrier. Alternatively or additionally, so as to cater for some time pre-scheduled data transmission, e.g., SPS, the group members are allocated a certain subframe pattern. Alternatively or additionally, there are included various interference levels that a group suffers from the SUEs, so as to satisfy a different traffic load and QoS requirement.

In step S80, the PeNB 30 signals the detected uplink interfering sources and piggybacks the information of the ICIM.

In step S90, based on the grouped UE scheduling information contained in the ICIM, the MeNB 20 can take appropriate measures, to accomplish the co-scheduling and reduce the inter-cell UL->DL interference. For example, according to examples of embodiments of the invention, based on ICIM, the

MeNB 20 derives the UL interfering source (the respective SMUE), and the inter-cell mapped group and inter-cell unmapped group, On this basis, in the co-scheduling, the MeNB 20 determined that the MUEs being outside of the UL interference areas are free from the restriction of co-scheduling criteria. On the other hand, for the addressed subframes, carrier, partitioned frequency band and PRBs in the ICIM used by an inter-cell mapped group, the scheduling of the corresponding uplink interfering sources is allowed. On the other hand, for the addressed subframes, carrier, partitioned frequency band and PRBs in the ICIM used by the inter-cell unmapped group, the scheduling of the corresponding uplink interfering source is prohibited.

It is to be noted that the co-scheduling of an UL interfering source with a classified inter-cell group can be priority based according to various interference levels indicated in the ICIM.

Fig. 4 shows a diagram illustrating an interference determination procedure in network elements of the communication network structure shown in Figs. 1 and 2 according to examples of embodiments of the invention. Specifically, Fig , 4 shows an example of interference detection by the PUEs as conducted in step S50 of Fig . 3.

As illustrated in Fig. 4, when the PeNB 30 selects, for example, PUE1, PUE3 and PUE4 as selected PUE for interference detection, the PUEs monitor for communications from the SMUEs using the preamble/SRS patterns indicated in the communication information. As a result of the monitoring, each of the selected PUE lists the sensed interference signal strength that the respective PUE suffers from the SMUEs. For example, as indicated in Fig. 4, PUE1 lists an respective interference signal strength (or another interference level indicator) of 5dB for SMUE1, lOdB for SMUE2, -2dB for SMUE3, and -5dB for SMUE4. The other PUEs, i.e. PUE2 and PUE4, list corresponding values for the SMUEs as depicted in Fig . 4, According to examples of embodiments of the invention, a report containing the listed values is sent to the PeNB 30, wherein the reporting can be triggered, for example, as soon as a corresponding interference strength is detected, or based on a threshold so that the report is sent only when at least one SMUE exceeds a predetermined interference level.

Fig. 5 shows a diagram illustrating an ICIM generation in a communication network control element of the communication network structure shown in Figs. 1 and 2 according to examples of embodiments of the invention . Specifically, Fig . 5 shows an example for an ICIM table generated in the PeNB 30 after collecting the detection reports from the selected PUEs.

As indicated in Fig. 5, according to examples of embodiments of the invention, the PeNB 30 establishes the ICIM table to indicate the classified group ID, such as PUE group 1 and PUE group 2. Furthermore, a respective time resource, such as a scheduled subframe pattern is indicated. Moreover, a frequency subband (here 1 and 2) as well as a corresponding interference level (here "0" for uncritical interference, lowest interference etc, and "1" for highest interference or interference being above a threshold and hence to be considered) that the respective group suffers from a corresponding SMUE (SMUE1 to SMUE4) are indicated. In the example for an ICIM table shown in Fig. 5, it is indicated that for PUE group 1 the highest interference is caused by SMUE2 while the lowest interference is caused by SMUE4. Similarly, for PUE group 2, it is indicated that the highest interference is caused by SMUE3 while the lowest interference is caused by SMUEl.

However, as indicated above, according to further examples of embodiments of the invention, also other contents can be included in the ICIM . For example, instead of an indication of "0" and "1" for an interference level, a more detailed indication for an interference strength can be added. For example, according to further examples of embodiments of the invention, there are more interference levels available, e.g. more bits to represent the interference level, so as to offer for the SMUEs various scheduling priorities, for example in order to satisfy a perceived UE QoS.

For signaling the ICIM to the MeNB 20, according to examples of embodiments of the invention, a new message type or a new IE can be used.

Hence, as a result of the processing in step S90, with reference to the network structure indicated in Fig. 2, on the basis of the ICIM indicated in Fig . 5, for example, provided with the interference feedback information of step S80, the MeNB 20 learns for example that the SMUE2 is prohibited, the SMUE4 is free from interference and allowed for scheduling for the addressed frequency subband #1 and subframe #0, 2, 3 and 7 which are allocated to PUE group 1, for example. Likewise, the MeNB 20 learns that SMUE3 is prohibited, while SMUEl is allowed free from interference for scheduling for the addressed frequency subband#2 and subframe#l, 4 and 5, which are allocated to PUE group 2.

Hence, when implementing the inter-cell group co-scheduling procedure as described above, the PUE group 1 can be scheduled together with MUE4 in the same resource, and the PUE group 2 can be scheduled together with MUE1 in the same resource. On the other hand, the MUEs that are out of the union coverage area of the UL interference area to the PeIMB 30 and the PUE groups 1 and 2 are free of the scheduling resource restriction.

As the UL interference area can be significantly larger than the coverage area of PeIMB 30, due to the UL/DL asymmetry described above, it is possible that without further measures the available spectrum is not optimally used when conducting a separate resource allocation. According to examples of embodiments of the invention, in order to avoid spectral underutilization, the interference related information provided by the ICIM can be used to optimize the resource usage,

Figs. 6a and 6b show a respective SF implementation with a 3-sector configuration (sectors A, B and C) for illustrating a power frequency management of the MelMB and PeNB. Generally, the left-side diagram part illustrates a power frequency management of the MeNB with a respective transmission power and frequency resources Fl to F6 for sectors A to C allocated to cell-edge UEs and to cell center UEs of the macro celt, while the right-side diagram part illustrates a power frequency management of the PeIMB with a respective transmission power and frequency resources Fl to F6 for sectors A to C allocated to pico cell UEs.

In Fig. 6a, the hatched blocks with greater transmission power illustrate frequency subbands F1/F2, F3/F4 and F5/F6, respectively, which are used by cell-edge MUEs, while the white blocks (with possibly lower transmission power requirement) illustrate the respective frequency subband used for cell-center MUEs. In the comparative example is shown in Fig . 6a, the pico cell (right-side diagram) reuses frequency subbands used by the cell center MUEs of the macro cell with a reduced power, while it refrains from using the same frequency resources as cell-edge MUEs of the macro cell. Hence, as can be seen in the right-side diagram of Fig . 6a, resources remain unused. On the other hand, according to examples of embodiments of the invention, as shown in Fig. 6b, the interference information and co-scheduling procedure allows optimized resource utilization. As can be seen in the leftside diagram of Fig. 6b, resources (frequency subbands) for cell-edge MUEs such as SMUE1 (vertically hatched block) and SMUE4 (horizontally hatched block) are identified for the respective sectors A to C. Therefore, by considering the inter-cell grouping, the cell-edge resource Fl that is used for SMUE4 in sector A can be utilized by PUE group 1 (vertically hatched block), and the cell edge resource F2 that is used for SMUE1 in sector A can be utilized by PUE group 2 (horizontally hatched block). Likewise, resource F3/F4 can be respectively utilized by group 1/2 PUEs in sector B. Furthermore, resource F5/F6 can be respectively utilized by group 1/2 PUEs in sector C. Hence, the spectral utilization is substantially improved by the inter-cell co-scheduling based on ICIM.

Fig. 7 shows a flowchart illustrating a processing for conducting a communication control in a communication network structure as shown in Fig. 1 or Fig. 2 according to examples of embodiments of the invention. Specifically, Fig . 7 shows a processing used for interference feedback including interfering source identification and ICIM provisioning. The method in Fig. 7 is executed, according to examples of embodiments of the invention, in a communication network control element like the PeNB 30.

In step S100, communication information related to an access to a first cell, such as to the pico cell controlled by the PeNB 30, are provided, i.e. the communication information are transmitted to selected PUEs and to a communication network control element of a second cell (such as the MeNB). According to examples of embodiments of the invention, the communication information is provided when e.g. a flexible time configuration mode such as a flexible TDD configuration mode is enabled for the communications in network.

According to examples of embodiments of the invention, as the communication information, at least one of information regarding a contention-free preamble and information regarding a S S pattern is provided by the PeNB 30. The selected UEs (i.e. PUEs) are selected, for example, on the basis of predetermined selection criteria comprising for example a factor which is based on an estimation of a traffic load of a respective UE or on a location of the UEs in the pico cell, e.g. with regard to the vicinity of the cell edge to the respective PUE.

In step SI 10, interference reports from the selected PUEs are received and processed. According to examples of embodiments of the invention, the interference reports indicate an interference level information related to a communication conducted on resources indicated in the communication information and comprise an indication of an interference strength sensed by a selected PUE sending the report and an identification of a corresponding interference source (i.e. SMUE),

It is to be noted that the PeNB 30, according to examples of embodiments of the invention, receives and processes an access request based on the provided communication information from a MUE (SMUE) as well, wherein the access requesting MUE can be identified as an interference source by the PeNB 30.

In step S120, on the basis of the interference reports, an ICIM is generated by the PeNB 30. The ICIM indicates information of interferences caused in the pico cell by a transmission of a UE (MUE) of the macro cell. According to examples of embodiments of the invention, the ICIM is generated by using information concerning an interference suffered by the selected PUEs of a classified group (PUE group 1 or 2, for example) caused by a communication of the SMUE, and information concerning resources to be scheduled for the classified PUE group. According to examples of embodiments of the invention, the ICIM is generated by using at least on an identity of the classified PUE group, time resources (subframe and subframe pattern) to be scheduled, frequency resources (a PRB, a partitioned subband, and/or a carrier) to be scheduled, an interference level sensed (e.g. indication that it is above threshold or not, like 0 and 1, or indication of a certain level, etc.) at the selected PUEs, and information indicating a suspected interfering source (which SMUE is received at the indicated level. According to examples of embodiments of the invention, the inter-cell interference matrix is generated in accordance with a preset one of different possible coordination schemes, i.e. the information may be ordered in one of the ways described above.

In step S130, interference feedback information is sent to the MeNB. The interference feedback information comprises an identification of interference sources (as detected by the PeNB, for example, and the ICIM.

Then, the processing is terminated .

It is to be noted that according to examples of embodiments of the invention, the PeNB 30 is further configured to conduct a step of allocating to the PUEs, on the basts of the ICIM processing, resources for a communication and to set a transmission power for the communication on the allocated resources. The resources are allocated to the PUEs such that they correspond to resources allocated to a MUE which is determined to cause an interference equal to or below a tolerable threshold (i.e. no interference or negligible interference) to the PUE.

Fig . 8 shows a flowchart illustrating a processing for conducting a communication control in a communication network structure as shown in Fig. 1 or Fig. 2 according to examples of embodiments of the invention. Specifically, Fig. 8 shows a processing used for interference reporting including interfering source identification. The method in Fig. 8 is executed, according to examples of embodiments of the invention, in a communication element like an UE (PUE) 10.

In step S200, communication information received from the PeNB 30 (see step S100 in Fig . 7) are processed, which is related to an access to the PeNB 30 by an MUE 40. The communication information is received, for example, when the PUE 10 is a selected PUE, i.e. when it fulfills the selection criteria comprising e.g. a factor based on an estimation of a traffic load and a location of the PUE with regard to a cell edge. Furthermore, according to examples of embodiments of the invention, the communication information comprises at information regarding a contention-free preamble and information regarding a SRS pattern which are used be the MUE for the access attempt. As indicated above, according to examples of embodiments of the invention, the communication information is received when a flexible time (TDD) configuration mode is enabled for communications.

In step S210, the PUE 10 monitors for transmissions on resources indicated in the communication information and using the preamble SRS pattern.

In step S220, when a corresponding communication is received, the PUE 10 determines an interference level caused by the communication of the MUE 40. The interference level indicates, for example, the interference strength sensed for the communication of the MUE as the interference source. Furthermore, the interference level is related to a specific interfering source, i.e. the respective MUE is identified in step S230.

In step S240, an interference report is prepared and transmitted to the PeNB 20 so as to indicate the determined interference level and the identified interfering source. In order to decrease the overhead caused by a too frequent interference report transmission, according to examples of embodiments of the invention, the transmission of the interference report to the PeNB 20 is conducted when it is detected that the determined interference level exceeds a predetermined threshold.

Then, the processing is terminated.

Fig. 9 shows a flowchart illustrating a processing for conducting a communication control in a communication network structure as shown in Fig. 1 or Fig. 2 according to examples of embodiments of the invention. Specifically, Fig. 9 shows a processing used for interference source identification and co-scheduling. The method in Fig. 9 is executed, according to examples of embodiments of the invention, in a communication network control element like the MeNB 20. In step S300, communication information related to an access to a PeNB controlled cell provided by the PeNB 30 (see e.g. step S100 of Fig. 7) are received and processed. As described above, according to examples of embodiments of the invention, the communication information comprises e.g. information regarding a contention-free preamble and information regarding a SRS pattern. Furthermore, according to examples of embodiments of the invention, the communication information is received when a flexible time (TDD) configuration mode is enabled for communications.

In step S310, an access of selected MUEs (SMUEs) to the PeNB 30 is initiated. This is triggered, for example, by transmitting communication information to the selected MUEs. The MUEs are selected when they are assumed by the MeNB 20 to be suspected MUEs probably causing interference in the pico cell. To such SMUEs, the MeNB 20 allocates a specific part of the communication information (preamble, SRS pattern).

In step S320, the interference feedback information from the PeNB 30 are received and processed, including the identification of the interfering sources (the respective SMUE) and the ICIM. In the processing, for example, the MeNB 20 maps the respective preamble/SRS patterns with the SMUEs to which they are sent in order to determine the respective interference level caused. In step S330, on the basis of the information received in the interference feedback, co-scheduling of resources for UEs communicating in the network is conducted. For example, according to examples of embodiments of the invention, the co-scheduling comprises deriving of the identity of the SMUEs being interfering sources, an inter-cel! group establishment by ordering the UEs (MUEs and PUEs) in an inter-cell mapped group comprising UEs or groups of UEs having an interference level to each other which is equal to or smaller than a predetermined tolerable threshold, i.e. an interference level being negligible, and an inter-cell unmapped group comprising UEs or groups of UEs having an interference level to each other being higher than the predetermined tolerable threshold, i.e. an interference level to be considered. Furthermore, in the co-scheduling processing, same resources are scheduled for the inter-cell mapped group in terms of at least one of time and frequency resources, and respective different resources are scheduled for the inter-cell unmapped group in terms of at least one of time and frequency resources. That is, according to examples of embodiments of the invention, the co-scheduling of resources comprises a determination of

UEs (in particular of MUEs) being free from restrictions of co-scheduling since they cause no interference, for example, a co-scheduling of dedicated resources for UEs (MUEs and PUEs) belonging to an inter-cell mapped group, and a prohibition of scheduling of the same resources for UEs belonging to an inter-cell unmapped group (i.e. scheduling of different resources).

According to examples of embodiments of the invention, the co-scheduling comprises a priorization of e.g. MUEs in the scheduling. For example, according to examples of embodiments of the invention, resources are allocated to an MUE in a prioritized manner on the basis of interference ievei information included in the ICIM.

It is to be noted that according to examples of embodiments of the invention, the MeNB 20 is further configured to conduct a step of allocating to the PUEs, to the MUEs, resources for a communication and to set a transmission power for the communication on the allocated resources on the basis of the information provided in the ICIM. For example, the resources alfocated to the MUEs correspond to resources allocated to a PUE which is determined to suffer interference equal to or below a tolerable threshold by a communication of the MUE,

Then, the processing is terminated. In Fig. 10, a block circuit diagram illustrating a circuitry indicating a configuration of a communication network control element, such as the PeNB 30, is shown which is configured to implement the processing for the communication control as described in connection with the examples of embodiments of the invention. That is, a circuitry is shown which comprises at least one processor and at least one memory including computer program code the at least one memory and the computer program code being configured to, with the at least one processor, cause the PeNB 20 to perform functions described below, for example by executing a corresponding algorithm. It is to be noted that the communication network control element or PeNB 20 shown in Fig. 10 may comprise several further elements or functions besides those described herein below, which are omitted for the sake of simplicity as they are not essential for understanding the invention. Furthermore, even though reference is made to an eNB, the communication network control element may be also another device having a similar function, such as a modem chipset, a chip, a module etc., which can also be part of a BS or eNB or attached as a separate element to a BS or eNB, or the like.

The communication network control element or PeNB 30 may comprise a processing function or processor 31, such as a CPU or the like, which executes instructions given by programs or the like related to the control signal transmission control. The processor 31 may comprise one or more processing portions dedicated to specific processing as described below, or the processing may be run in a single processor. Portions for executing such specific processing may be also provided as discrete elements or within one or more further processors or processing portions, such as in one physical processor like a CPU or in several physical entities, for example. Reference signs 32 and 33 denote transceiver or input/output (I/O) units connected to the processor 31. The I/O units 32 may be used for communicating with a communication element like UE (PUE) 10 and the I/O units 33 may be used for communicating with another communication network control element like MeNB 20. The I/O units 32 and 33 may be a combined unit comprising communication equipment towards several network elements, or may comprise a distributed structure with a plurality of different interfaces for different network elements. Reference sign 34 denotes a memory usable, for example, for storing data and programs to be executed by the processor

31 and/or as a working storage of the processor 31.

The processor 31 is configured to execute processing related to the above described mechanism for communication control mechanism. In particular, the processor 31 comprises a sub-portion 311 as a processing portion which is usable for providing communication information to the PUE and MeNB. The portion 311 may be configured to perform a processing according to step SlOO of Fig. 7, for example. Furthermore, the processor 31 comprises a sub-portion 312 usable as a portion for processing received interference reports. The portion 312 may be configured to perform processing according to step SllO according to Fig. 7, for example. In addition, the processor 31 comprises a sub-portion 313 as a processing portion which is usable for generating the ICIM. The portion 313 may be configured to perform processing according to step S130 of Fig. 7, for example. Furthermore, the processor 31 comprises a sub-portion 314 as a processing portion which is usable for generating and sending the interference feedback to the MefMB 20. The portion 314 may be configured to perform processing according to step S140 of Fig, 7, for example. In addition, the processor 31 comprises a sub-portion 315 as a processing portion which is usable for allocating resources to PUEs.

In Fig. 11, a block circuit diagram illustrating a circuitry indicating a configuration of a communication element, such as the UE (PUE) 10, is shown which is configured to implement the communication control as described in connection with the examples of embodiments of the invention. That is, a circuitry is shown which comprises at least one processor and at least one memory including computer program code the at least one memory and the computer program code being configured to, with the at least one processor, cause the PUE 10 to perform functions described below, for example by executing a corresponding algorithm. It is to be noted that the communication element or PUE 10 shown in Fig. 11 may comprise several further elements or functions besides those described herein below, which are omitted for the sake of simplicity as they are not essential for understanding the invention. Furthermore, even though reference is made to an UE, the communication element may be also another terminal device having a similar function, such as a modem chipset, a chip, a module etc., which can also be part of an UE or attached as a separate element to a UE, or the like.

The communication element or PUE 10 may comprise a processing function or processor 11, such as a CPU or the like, which executes instructions given by programs or the like related to the control signal transmission control. The processor 11 may comprise one or more processing portions dedicated to specific processing as described below, or the processing may be run in a single processor. Portions for executing such specific processing may be also provided as discrete elements or within one or more further processors or processing portions, such as in one physical processor like a CPU or in several physical entities, for example. Reference sign 12 denotes transceiver or input/output (I/O) units connected to the processor 11. The I/O unit 12 may be used for communicating with a communication network control element like PeNB 30. The I/O unit 12 may be a combined unit comprising communication equipment towards several network elements, or may comprise a distributed structure with a plurality of different interfaces for different network elements. Reference sign 13 denotes a memory usable, for example, for storing data and programs to be executed by the processor 11 and/or as a working storage of the processor 11.

The processor 11 is configured to execute processing related to the above described communication control mechanism. In particular, the processor 11 comprises a sub-portion 111 as a processing portion which is usable for receiving and processing communication information from the PeNB 30. The portion 111 may be configured to perform a processing of step S200 according to Fig. 8, for example. Furthermore, the processor 11 comprises a sub-portion 112 usable as a portion for monitoring for communications indicated by the communication information. The portion 112 may be configured to perform a processing of step S210 according to Fig. 8, for example. In addition, the processor 11 comprises a sub-portion 113 as a processing portion which is usable for determining an interference caused by the communications and for identifying a respective interfering source. The portion 113 may be configured to perform processings according to steps S220 and S230 of Fig. 8, for example. Moreover, the processor 11 comprises a sub-portion 114 as a processing portion which is usable for sending or signaling the interference report to the PeNB 30. The portion 114 may be configured to perform processing according to step S240 of Fig. 8, for example. In Fig. 12, a biock circuit diagram illustrating a circuitry indicating a configuration of a communication network control element such as the MeNB 20, is shown which is configured to implement the processing for the communication control as described in connection with the examples of embodiments of the invention. That is, a circuitry is shown which comprises at least one processor and at least one memory including computer program code the at least one memory and the computer program code being configured to, with the at least one processor, cause the MeNB 20 to perform functions described below, for example by executing a corresponding algorithm. It is to be noted that the communication network control element or MeNB 20 shown in Fig. 9 may comprise several further elements or functions besides those described herein below, which are omitted for the sake of simplicity as they are not essential for understanding the invention. Furthermore, even though reference is made to an eNB, the communication network control element may be also another device having a similar function, such as a modem chipset, a chip, a module etc., which can also be part of an eNB or attached as a separate element to an eNB, or the like.

The communication network control element or MeNB 20 may comprise a processing function or processor 21, such as a CPU or the like, which executes instructions given by programs or the like related to the control signal transmission control. The processor 21 may comprise one or more processing portions dedicated to specific processing as described below, or the processing may be run in a single processor. Portions for executing such specific processing may be also provided as discrete elements or within one or more further processors or processing portions, such as in one physical processor like a CPU or in several physical entities, for example. Reference signs 22 and 23 denote transceiver or input/output (I/O) units connected to the processor 21. The I/O unit 22 may be used for communicating with a communication element like UE 40, and the I/O unit 23 may be used for communicating with a communication network control element like PeNB 30. The I/O units 22 and 23 may be a combined unit comprising communication equipment towards several network elements, or may comprise a distributed structure with a plurality of different interfaces for different network elements. Reference sign 24 denotes a memory usable, for example, for storing data and programs to be executed by the processor 21 and/or as a working storage of the processor 21.

The processor 21 is configured to execute processing related to the above described mechanism for controlling a discovery of small cells. In particular, the processor 21 comprises a sub-portion 211 as a processing portion which is usable for receiving and processing the communication information sent for example by the PeIMB 30. The portion 211 may be configured to perform a processing of step S300 of Fig. 9, for example. Furthermore, the processor 21 comprises a sub-portion 212 usable as a portion for initiating an access procedure to the PeNB 30 by SMUEs. The portion 212 may be configured to perform processing according to step S310 of Fig. 9, for example. Moreover, the processor 21 comprises a sub-portion 213 usable as a portion for receiving and processing an interference feedback from the PeNB 30. The portion 213 may be configured to perform processing according to step S320 of Fig. 9, for example. In addition, the processor 21 comprises a sub-portion 214 usable as a portion for conducting a co- scheduling processing. The portion 214 may be configured to perform processing according to step S330 of Fig. 9, for example. In addition, the processor 21 comprises a sub-portion 215 as a processing portion which is usable for allocating resources to MUEs.

Even though in the above described examples of embodiments of the invention a communication network configuration is described where a pico cell is located in a macro celi, causing the interferences in UL and DL directions discussed above, it is to be noted that examples of embodiments of the invention are also applicable in a network configuration where plural cells of the same category, such as plural small or pico cells, are considered to be aggressor and victim cell. Furthermore, also a scenario with one or more macro cells and one or more pico cells can apply the above described communication control mechanism.

Furthermore, while in the above described examples of embodiments of the invention scenarios are considered where the UL communication occurs in the macro cell while the DL communication occurs in the pico cell, examples of embodiments of the invention are also applicable in scenarios where the UL communication occurs in the pico cell while the DL communication occurs in the macro cell.

According to further examples of embodiments of the invention, there is provided an apparatus comprising communication information providing means for providing communication information related to an access to a first cell of a communication network by causing transmission of the communication information to selected communication elements connected to the first cell and to a communication network control element of a second cell of the communication network, interference report processing means for receiving and processing interference reports from the selected communication elements, wherein the interference reports indicate an interference level information related to a communication conducted on resources indicated in the communication information, inter-cell interference matrix generation means for generating, on the basis of the interference reports, an inter-cell interference matrix indicating information of interferences caused in the first cell by a transmission of the second cell, and interference feedback means for causing transmission of interference feedback information to the communication network control element of the second cell, the interference feedback information comprising an identification of interference sources and the inter-cell interference matrix.

In addition, according to further examples of embodiments of the invention, there is provided an apparatus comprising communication information processing means for processing communication information received from a communication network control element of a first cell of a communication network and being related to an access to the first cell by at least one communication element of a second cell of the communication network, transmission monitoring means for monitoring for transmissions on resources indicated in the communication information, interference determining means for determining an interference level caused by a communication conducted on the resources indicated in the communication information, and for identifying an interfering source on the basis of the communication information, and interference report transmission means for causing transmission of an interference report to the communication network control element of the first cell, wherein the interference report indicates the determined interference level and the identified interfering source,

Moreover, according to further examples of embodiments of the invention, there is provided an apparatus comprising communication information processing means for processing communication information related to an access to a first cell of a communication network and provided by a communication network control element of the first cell of the communication network, access initiating means for initiating an access of a selected communication element of the second cell to the first cell by causing transmission of the communication information to the selected communication element, interference feedback processing means for receiving and processing interference feedback information from the communication network control element of the first cell, the interference feedback information comprising an identification of interference sources and an inter-cell interference matrix indicating information of interferences caused in the first cell by a transmission of the selected communication element, and co-scheduling processing means for conducting a co- scheduling of resources for communication elements communicating in the first and second cells on the basis of the interference feedback information.

For the purpose of the present invention as described herein above, it should be noted that

- an access technology via which signaling is transferred to and from a network element may be any technology by means of which a network element or sensor node can access another network element or node (e.g. via a base station or generally an access node). Any present or future technology, such as WLAN (Wireless Local Access Network), WiMAX (Worldwide Interoperability for Microwave Access), LTE, LTE-A, Bluetooth, Infrared, and the like may be used; although the above technologies are mostly wireless access technologies, e.g. in different radio spectra, access technology in the sense of the present invention implies also wired technologies, e.g . IP based access technologies like cable networks or fixed lines but also circuit switched access technologies; access technologies may be distinguishable in at least two categories or access domains such as packet switched and circuit switched, but the existence of more than two access domains does not impede the invention being applied thereto, - usable communication networks and transmission nodes may be or comprise any device, apparatus, unit or means by which a station, entity or other user equipment may connect to and/or utilize services offered by the access network; such services include, among others, data and/or (audio-) visual communication, data download etc.;

- a user equipment or communication network element may be any device, apparatus, unit or means which is usable as a user communication device and by which a system user or subscriber may experience services from an access network, such as a mobile phone, a wireless mobile terminal, a personal digital assistant PDA, a smart phone, a personal computer (PC), a laptop computer, a desktop computer or a device having a corresponding functionality, such as a modem chipset, a chip, a module etc., which can also be part of a UE or attached as a separate element to a UE, or the like, wherein corresponding devices or terminals may be, for example, an LTE, an LTE-A, a TETRA (Terrestrial Trunked Radio), an UMTS, a GSM/EDGE etc. smart mobile terminal or the like;

- method steps likely to be implemented as software code portions and being run using a processor at a network element or terminal (as examples of devices, apparatuses and/or modules thereof, or as examples of entities including apparatuses and/or modules for it), are software code independent and can be specified using any known or future developed programming language as long as the functionality defined by the method steps is preserved;

- generally, any method step is suitable to be implemented as software or by hardware without changing the idea of the invention in terms of the functionality implemented;

- method steps and/or devices, apparatuses, units or means likely to be implemented as hardware components at a terminal or network element, or any module(s) thereof, are hardware independent and can be implemented using any known or future developed hardware technology or any hybrids of these, such as a microprocessor or CPU (Central Processing Unit), MOS (Metal Oxide Semiconductor), CMOS (Complementary MOS), BiMOS (Bipolar MOS), BiCMOS (Bipolar CMOS), ECL (Emitter Coupled Logic), TTL (Transistor-Transistor Logic), etc., using for example ASIC (Application Specific IC (Integrated Circuit)) components, FPGA (Field-programmable Gate Arrays) components, CPLD (Complex Programmable Logic Device) components or DSP (Digital Signal Processor) components; in addition, any method steps and/or devices, units or means likely to be implemented as software components may for example be based on any security architecture capable e.g. of authentication, authorization, keying and/or traffic protection;

- devices, apparatuses, units or means can be implemented as individual devices, apparatuses, units or means, but this does not exclude that they are implemented in a distributed fashion throughout the system, as long as the functionality of the device, apparatus, unit or means is preserved; for example, for executing operations and functions according to examples of embodiments of the invention, one or more processors may be used or shared in the processing, or one or more processing sections or processing portions may be used and shared in the processing, wherein one physical processor or more than one physical processor may be used for implementing one or more processing portions dedicated to specific processing as described,

- an apparatus may be represented by a semiconductor chip, a chipset, or a

(hardware) module comprising such chip or chipset; this, however, does not exclude the possibility that a functionality of an apparatus or module, instead of being hardware implemented, be implemented as software in a (software) module such as a computer program or a computer program product comprising executable software code portions for execution/being run on a processor;

- a device may be regarded as an apparatus or as an assembly of more than one apparatus, whether functionally in cooperation with each other or functionally independently of each other but in a same device housing, for example.

Furthermore, as used in this application, the terms , device' or , circuitry' refer to all of the following : (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) combinations of circuits and software (and/or firmware), such as (as applicable) : (i) a combination of processor(s) or (ii) portions of processor(s)/software (including digital signal processor(s)), software, and memory(or memories) working together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) circuits, such as a microprocessor (or plural microprocessors) or a portion of a microprocessor (or plural microprocessors), that requires/require software or firmware for operation, even if the software or firmware is not physically present. This definition of 'circuitry' applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term "circuitry" would also cover an implementation of merely a processor (or multiple processors) or portion of a processor and its

(or their) accompanying software and/or firmware. The term "circuitry" would also cover, for example and if applicable to the particular claim element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in server, a cellular network device, or other network device

As described above, there is provided a mechanism for controlling communications in communication networks using a resource co-scheduling procedure for handling inter-cell interferences. Communication information providing information related to an access to a first ceil is provided by a first

(pico) cell to UEs of the first cell and to a second (macro) cell. The pico UEs monitor for communications from UEs of the second (macro) cell and measure an interference level caused thereby. In the pico cell, an inter-cell interference matrix is generated from the reported interferences and provided to the second cell. The second cell conducts a co-scheduling of resources on the basis of the information contained in the inter-cell interference matrix.

Although the present invention has been described herein before with reference to particular embodiments thereof, the present invention is not limited thereto and various modifications can be made thereto.

Claims

WHAT IS CLAIMED IS:

1. An apparatus comprising

at (east one processor; and

at least one memory including computer program code;

wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to perform

a communication information providing function configured to provide communication information related to an access to a first cell of a communication network by causing transmission of the communication information to selected communication elements connected to the first cell and to a communication network control element of a second cell of the communication network,

an interference report processing function configured to receive and process interference reports from the selected communication elements, wherein the interference reports indicate an interference level information related to a communication conducted on resources indicated in the communication information,

an inter-cell interference matrix generation function configured to generate, on the basis of the interference reports, an inter-cell interference matrix indicating information of interferences caused in the first cell by a transmission of the second cell, and

an interference feedback function configured to cause transmission of interference feedback information to the communication network control element of the second cell, the interference feedback information comprising an identification of interference sources and the inter-cell interference matrix.

2. The apparatus according to claim 1, wherein the at least one memory and the computer program code are further configured, with the at least one processor, to cause the apparatus at least to perform

an access transmission processing function configured to receive and process an access request based on the provided communication information, wherein the processing comprises identifying a communication element as an interference source.

3. The apparatus according to claim 1 or 2, wherein the communication information providing function is further configured to provide, as the communication information, at least one of information regarding a contention-free preamble and information regarding a sounding reference signal pattern.

4. The apparatus according to any of claims 1 to 3, wherein the communication information providing function is further configured to select the selected communication elements connected to the first cell on the basis of predetermined selection criteria comprising at least one of a factor based on an estimation of a traffic load of communication elements and a location of communication elements with regard to an edge of the first cell.

5. The apparatus according to any of claims 1 to 4, wherein the interference level information related to the communication conducted on resources indicated in the communication information comprises an indication of an interference strength sensed by a selected communication element and an identification of an interference source.

6. The apparatus according to any of claims 1 to 5, wherein the inter-cell interference matrix generation function is further configured to generate the inter-cell interference matrix by introducing information concerning interference suffered by the selected communication elements of a classified group of communication elements in the first cell caused by a communication of communication elements connected to the second cell and information concerning resources to be scheduled for the classified group of communication elements.

7. The apparatus according to claim 6, wherein the inter-cell interference matrix generation function is further configured to generate the inter-cell interference matrix by introducing at least one of the following information:

- an identity of the classified group,

- time resources to be scheduled, comprising at least one of a specific subframe and a subframe pattern, - frequency resources to be scheduled, comprising at least one of a physical resource block, a partitioned subband, and a carrier,

- an interference level sensed at the selected communication elements, and

- an information indicating a suspected interfering source.

8. The apparatus according to any of claims 1 to 6, wherein the inter-cell interference matrix generation function is further configured to generate the inter-cell interference matrix in accordance with a preset coordination scheme.

9. The apparatus according to any of claims 1 to 8, wherein the at least one memory and the computer program code are further configured, with the at least one processor, to cause the apparatus at least to perform

a resource allocation function configured to allocate, to a communication element connected to the first cell, resources for a communication and to set a transmission power for the communication on the allocated resources on the basis of the information provided in the inter- cell interference matrix, wherein the resources allocated to the communication element connected to the first cell correspond to resources allocated to a communication element connected to the second cell, which is determined to cause interference equal to or below a tolerable threshold to the communication element connected to the first celt according to the inter-cell interference matrix.

10. The apparatus according to any of claims 1 to 9, wherein the communication information providing function is configured to provide the communication information when a flexible time configuration mode is enabled for communications in the first and second cell.

11. The apparatus according to any of claims 1 to 10, wherein

the apparatus is comprised in a communication network control element of the first cell, in particular a base station or an evolved node B of Long Term Evolution or Long Term Evolution Advanced communication network using a small area cell, wherein the communication network control element of the second cell is a base station or an evolved node B of a Long Term Evolution or Long Term Evolution Advanced communication network using a macro cell or another small area cell, and the communication element is a terminal device or user equipment connectable to at least the communication network control element of the first cell.

12. An apparatus comprising

at least one processor; and

at least one memory including computer program code;

a communication information processing function configured to process communication information received from a communication network control element of a first cell of a communication network and being related to an access to the first cell by at least one communication element of a second cell of the communication network,

a transmission monitoring function configured to monitor for transmissions on resources indicated in the communication information, an interference determining function configured to determine an interference level caused by a communication conducted on the resources indicated in the communication information, and to identify an interfering source on the basis of the communication information, and

an interference report transmission function configured to cause transmission of an interference report to the communication network control element of the first cell, wherein the interference report indicates the determined interference level and the identified interfering source.

13. The apparatus according to claim 12, wherein the communication information comprises at least one of information regarding a contention- free preamble and information regarding a sounding reference signal pattern.

14. The apparatus according to claim 12 or 13, wherein the communication information is received when selection criteria are fulfilled, wherein the selection criteria comprise at least one of a factor based on an estimation of a traffic load of communication elements and a location of communication elements with regard to an edge of the first cell.

15. The apparatus according to any of claims 12 to 14, wherein the interference level indicates an interference strength sensed for at least one communication of an interference source and a relation to an identification of the respective interference source.

16. The apparatus according to any of claims 12 to 15, wherein the interference report transmission function is further configured to cause the transmission of the interference report to the communication network control element of the first cell when the determined interference level exceeds a predetermined threshold.

17. The apparatus according to any of claims 12 to 16, wherein the communication information is received when a flexible time configuration mode is enabled for communications in the first and second cell.

18. The apparatus according to any of claims 12 to 17, wherein

the apparatus is comprised in a communication element of the first cell, in particular terminal device or user equipment connectabie to at least the communication network control element of the first cell, wherein the communication network control element of the first cell is in particular a base station or an evolved node B of Long Term Evolution or Long Term Evolution Advanced communication network using a small area cell, and wherein the communication network control element of the second cell is a base station or an evolved node B of a Long Term Evolution or Long Term Evolution Advanced communication network using a macro cell or another small area cell.

19. An apparatus comprising

at least one processor; and

at least one memory including computer program code;

wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to perform a communication information processing function configured to process communication information related to an access to a first cell of a communication network and provided by a communication network control element of the first cell of the communication network,

an access initiating function configured to initiate an access of a selected communication element of the second cell to the first cell by causing transmission of the communication information to the selected communication element,

an interference feedback processing function configured to receive and process interference feedback information from the communication network control element of the first cell, the interference feedback information comprising an identification of interference sources and an inter-cell interference matrix indicating information of interferences caused in the first cell by a transmission of the selected communication element, and

a co-scheduling processing function configured to conduct a co- scheduling of resources for communication elements communicating in the first and second cells on the basis of the interference feedback information.

20. The apparatus according to claim 19, wherein the at least one memory and the computer program code are further configured, with the at least one processor, to cause the apparatus at least to perform

a communication element selection function configured to select the selected communication element to which the communication information for initiating an access to the first cell is transmitted among communication elements being connected to a second cell which are suspected to represent an interfering source for the first cell, and

an assigning function configured to assign a specific part of the communication information to each selected communication element.

21. The apparatus according to claim 19 or 20, wherein the communication information comprises at least one of information regarding a contention- free preamble and information regarding a sounding reference signal pattern.

22. The apparatus according to any of claims 19 to 21, wherein the inter- cell interference matrix comprises information concerning interference suffered by communication elements of a classified group of communication elements in the first ceil caused by a communication of the selected communication element connected to the first cell and information concerning resources to be scheduled for the classified group of communication elements.

23. The apparatus according to claim 22, wherein the inter-cell interference matrix comprises at least one of the following information :

- an identity of the classified group,

- time resources to be scheduled, comprising at least one of a specific subframe and a subframe pattern,

- frequency resources to be scheduled, comprising at least one of a physical resource block, a partitioned subband, and a carrier,

- an interference level sensed at the communication elements of the first cell, and

- an information indicating the selected communication element being a suspected interfering source.

24. The apparatus according to any of claims 19 to 23, wherein the inter- celi interference matrix is formed in accordance with a preset coordination scheme.

25. The apparatus according to any of claims 19 to 24, wherein the co- scheduling processing function is further configured, for conducting the co- scheduling of resources for communications in the first and second ceils on the basis of the interference feedback information, to derive from the inter- cell interference matrix

- the identity of the selected communication element being the interfering source,

- an inter-cell mapped group comprising communication elements or groups of communication elements of the first and second cell having an interference level to each other which is equal to or smaller than a predetermined tolerable threshold, and - an inter-celi unmapped group comprising communication elements or groups of communication elements of the first and second cell having an interference level to each other being higher than the predetermined tolerable threshold,

wherein the co-scheduling processing function is further configured to schedule same resources for the inter-cell mapped group in terms of at least one of time and frequency resources, and

to schedule different resources for the inter-cell unmapped group in terms of at least one of time and frequency resources.

26. The apparatus according to claim 25, wherein the co-scheduling processing function is further configured, for conducting the co-scheduling of resources for communications in the first and second cells on the basis of the interference feedback information,

to determine communication elements of the second cell being free from restrictions of co-scheduling,

to conduct co-scheduling of dedicated resources for communication elements belonging to an inter-cell mapped group, and

to prohibit scheduling of same resources for communication elements belonging to an inter-cell unmapped group.

27. The apparatus according to claim 25 or 26, wherein the co-scheduling processing function is further configured, for conducting the co-scheduling of resources for communications in the first and second cells on the basis of the interference feedback information,

to prioritize an allocation of resources to one or more of the communication elements on the basis of interference level information included in the inter-cell interference matrix.

28. The apparatus according to any of claims 19 to 27, wherein the at least one memory and the computer program code are further configured, with the at least one processor, to cause the apparatus at least to perform

a resource allocation function configured to allocate, to a communication element connected to the second cell, resources for a communication and to set a transmission power for the communication on the allocated resources on the basis of the information provided in the inter- cell interference matrix, wherein the resources allocated to the communication element connected to the second cell correspond to resources allocated to a communication element connected to the first cell, which is determined to suffer interference equal to or below a tolerable threshold by a communication of the communication element connected to the second cell according to the inter-cell interference matrix,

29. The apparatus according to any of claims 19 to 28, wherein the communication information is received when a flexible time configuration mode is enabled for communications in the first and second cell.

30. The apparatus according to any of claims 19 to 29, wherein

the apparatus is comprised in a communication network control element of the second cell, in particular a base station or an evolved node B of Long Term Evolution or Long Term Evolution Advanced communication network using a macro cell or a small area cell, wherein the communication network control element of the first cell is a base station or an evolved node B of a Long Term Evolution or Long Term Evolution Advanced communication network using another small area cell, and the communication element is a terminal device or user equipment connectable to at least the communication network control element of the second cell.

31. A method comprising

providing communication information related to an access to a first cell of a communication network by causing transmission of the communication information to selected communication elements connected to the first cell and to a communication network control element of a second cell of the communication network,

receiving and processing interference reports from the selected communication elements, wherein the interference reports indicate an interference level information related to a communication conducted on resources indicated in the communication information,

generating, on the basis of the interference reports, an inter-cell interference matrix indicating information of interferences caused in the first cell by a transmission of the second cell, and causing transmission of interference feedback information to the communication network control element of the second cell, the interference feedback information comprising an identification of interference sources and the inter-cell interference matrix.

32. The method according to claim 31, further comprising

receiving and processing an access request based on the provided communication information, wherein the processing comprises identifying a communication element as an interference source.

33. The method according to claim 31 or 32, further comprising providing, as the communication information, at least one of information regarding a contention -free preamble and information regarding a sounding reference signal pattern.

34. The method according to any of claims 31 to 33, further comprising selecting the selected communication elements connected to the first cell on the basis of predetermined selection criteria comprising at least one of a factor based on an estimation of a traffic load of communication elements and a location of communication elements with regard to an edge of the first ceil.

35. The method according to any of claims 31 to 34, wherein the interference level information related to the communication conducted on resources indicated in the communication information comprises an indication of an interference strength sensed by a selected communication element and an identification of an interference source.

36. The method according to any of claims 31 to 35, further comprising generating the inter-ceii interference matrix by introducing information concerning interference suffered by the selected communication elements of a classified group of communication elements in the first cell caused by a communication of communication elements connected to the second cell and information concerning resources to be scheduled for the classified group of communication elements.

37. The method according to claim 36, further comprising generating the inter-cell interference matrix by introducing at least one of the following information :

- an identity of the classified group,

- an interference level sensed at the selected communication elements, and

- an information indicating a suspected interfering source.

38. The method according to any of claims 31 to 36, further comprising generating the inter-cell interference matrix in accordance with a preset coordination scheme.

39. The method according to any of claims 31 to 38, further comprising

allocating, to a communication element connected to the first cell, resources for a communication and to set a transmission power for the communication on the allocated resources on the basis of the information provided in the inter-cell interference matrix, wherein the resources allocated to the communication element connected to the first cell correspond to resources allocated to a communication element connected to the second cell, which is determined to cause interference equal to or below a tolerable threshold to the communication element connected to the first cell according to the inter-cell interference matrix.

40. The method according to any of claims 31 to 39, wherein the communication information is provided when a flexible time configuration mode is enabled for communications in the first and second cell.

41. The method according to any of claims 31 to 40, wherein

the method is implemented in a communication network control element of the first cell, in particular a base station or an evolved node B of Long Term Evolution or Long Term Evolution Advanced communication network using a small area cell, wherein the communication network control element of the second cell is a base station or an evolved node B of a Long Term Evolution or Long Term Evolution Advanced communication network using a macro cell or another small area cell, and the communication element is a terminal device or user equipment connectable to at least the communication network control element of the first cell.

42. A method comprising

processing communication information received from a communication network control element of a first cell of a communication network and being related to an access to the first cell by at least one communication element of a second cell of the communication network, monitoring for transmissions on resources indicated in the communication information,

determining an interference level caused by a communication conducted on the resources indicated in the communication information, identifying an interfering source on the basis of the communication information, and

causing transmission of an interference report to the communication network control element of the first cell, wherein the interference report indicates the determined interference level and the identified interfering source.

43. The method according to claim 42, wherein the communication information comprises at least one of information regarding a contention- free preamble and information regarding a sounding reference signal pattern .

44. The method according to claim 42 or 43, wherein the communication information is received when selection criteria are fulfilled, wherein the selection criteria comprise at least one of a factor based on an estimation of a traffic load of communication elements and a location of communication elements with regard to an edge of the first cell.

45. The method according to any of claims 42 to 44, wherein the interference level indicates an interference strength sensed for at least one communication of an interference source and a relation to an identification of the respective interference source.

46. The method according to any of claims 42 to 45, further comprising causing the transmission of the interference report to the communication network control element of the first cell when the determined interference level exceeds a predetermined threshold.

47. The method according to any of claims 42 to 46, wherein the communication information is received when a flexible time configuration mode is enabled for communications in the first and second cell.

48. The method according to any of claims 42 to 47, wherein

the method is implemented in a communication element of the first cell, in particular terminal device or user equipment connectable to at least the communication network control element of the first cell, wherein the communication network control element of the first cell is in particular a base station or an evolved node B of Long Term Evolution or Long Term Evolution Advanced communication network using a small area cell, and wherein the communication network control element of the second cell is a base station or an evolved node B of a Long Term Evolution or Long Term Evolution Advanced communication network using a macro cell or another small area cell.

49. A method comprising

processing communication information related to an access to a first cell of a communication network and provided by a communication network control element of the first cell of the communication network,

initiating an access of a selected communication element of the second cell to the first cell by causing transmission of the communication information to the selected communication element,

receiving and processing interference feedback information from the communication network control element of the first cell, the interference feedback information comprising an identification of interference sources and an inter-cell interference matrix indicating information of interferences caused in the first cell by a transmission of the selected communication element, and

conducting a co-scheduling of resources for communication elements communicating in the first and second cells on the basis of the interference feedback information.

50. The method according to claim 49, further comprising

selecting the selected communication element to which the communication information for initiating an access to the first cell is transmitted among communication elements being connected to a second cell which are suspected to represent an interfering source for the first cell, and

assigning a specific part of the communication information to each selected communication element.

51. The method according to claim 49 or 50, wherein the communication information comprises at least one of information regarding a contention- free preamble and information regarding a sounding reference signal pattern.

52. The method according to any of claims 49 to 51, wherein the inter-cell interference matrix comprises information concerning interference suffered by communication elements of a classified group of communication elements in the first cell caused by a communication of the selected communication element connected to the first cell and information concerning resources to be scheduled for the classified group of communication elements.

53. The method according to claim 52, wherein the inter-cell interference matrix comprises at least one of the following information:

- an identity of the classified group,

- frequency resources to be scheduled, comprising at least one of a physical resource block, a partitioned subband, and a carrier, - an interference level sensed at the communication elements of the first cell, and

54. The method according to any of claims 49 to 53, wherein the inter-cell interference matrix is formed in accordance with a preset coordination scheme.

55. The method according to any of claims 49 to 54, further comprising, for conducting the co-scheduling of resources for communications in the first and second cells on the basis of the interference feedback information, deriving from the inter-cell interference matrix

- an inter-cell mapped group comprising communication elements or groups of communication elements of the first and second cell having an interference level to each other which is equal to or smaller than a predetermined tolerable threshold, and

- an inter-cell unmapped group comprising communication elements or groups of communication elements of the first and second cell having an interference level to each other being higher than the predetermined tolerable threshold,

scheduling same resources for the inter-cell mapped group in terms of at least one of time and frequency resources, and

scheduling different resources for the inter-cell unmapped group in terms of at least one of time and frequency resources.

56. The method according to claim 55, further comprising, for conducting the co-scheduling of resources for communications in the first and second cells on the basis of the interference feedback information,

determining communication elements of the second cell being free from restrictions of co-scheduling,

conducting co-scheduling of dedicated resources for communication elements belonging to an inter-cell mapped group, and prohibiting scheduling of same resources for communication elements belonging to an inter-cell unmapped group.

57. The method according to claim 55 or 56, further comprising, for conducting the co-scheduling of resources for communications in the first and second cells on the basis of the interference feedback information,

prioritizing an allocation of resources to one or more of the communication elements on the basis of interference level information included in the inter-cell interference matrix.

58. The method according to any of claims 49 to 57, further comprising

allocating, to a communication element connected to the second cell, resources for a communication and to set a transmission power for the communication on the allocated resources on the basis of the information provided in the inter-cell interference matrix, wherein the resources allocated to the communication element connected to the second cell correspond to resources allocated to a communication element connected to the first cell, which is determined to suffer interference equal to or below a tolerable threshold by a communication of the communication element connected to the second cell according to the inter-cell interference matrix,

59. The method according to any of claims 49 to 58, wherein the communication information is received when a flexible time configuration mode is enabled for communications in the first and second cell.

60. The method according to any of claims 49 to 59, wherein

the method is implemented in a communication network control element of the second cell, in particular a base station or an evolved node B of Long Term Evolution or Long Term Evolution Advanced communication network using a macro cell or a small area cell, wherein the communication network control element of the first cell is a base station or an evolved node B of a Long Term Evolution or Long Term Evolution Advanced communication network using another small area ceil, and the communication element is a terminal device or user equipment connectable to at least the communication network control element of the second cell.

61. A computer program product for a computer, comprising software code portions for performing the steps of any of claims 31 to 60, when said product is run on the computer.

62. The computer program product according to claim 61, further comprising a computer-readable medium on which said software code portions are stored.

63. The computer program product according to claim 61, wherein the computer program product is directly loadable into the internal memory of the computer and/or transmittable via a network by means of at least one of upload, download and push procedures.