WO2013181829A1

WO2013181829A1 - Apparatuses, methods and computer program products related to improvements in carrier loading status reports

Info

Publication number: WO2013181829A1
Application number: PCT/CN2012/076608
Authority: WO
Inventors: Lili Zhang; Haiming Wang; Wei Hong
Original assignee: Renesas Mobile Corporation
Priority date: 2012-06-07
Filing date: 2012-06-07
Publication date: 2013-12-12

Abstract

According to at least an aspect of the present invention, there is provided an apparatus, comprising a controller configured to receive a feedback signal indicative of a communication channel quality from at least one terminal, the at least one terminal communicating on a respective physical channel, the physical channel being a communication channel of the apparatus and of another entity, classify each terminal, based on the respective feedback signal, into one of at least two interference classes, derive, for at least one interference class, an indication of occupation of the respective channel by the terminals of the respective class. Correspondingly, its counterpart is proposed under another aspect, i.e. an apparatus, comprising a controller configured to receive, for at least one interference class, an indication of occupation of a respective physical channel by terminals of the respective class, the indication being associated to a respective physical channel, the physical channel being a communication channel of the apparatus and of another entity, decide on configurations to reduce interference for said physical channel used by the apparatus and the another entity based on the indication of occupation received for at least one interference class. Other aspects of examples of the present invention encompass corresponding methods and related computer program products.

Description

12 076608

APPARATUSES, METHODS AND COMPUTER PROGRAM

PRODUCTS RELATED TO IMPROVEMENTS IN CARRIER LOADING STATUS REPORTS Field of the invention

The present invention relates to apparatuses, methods and computer program products configured to achieve improvements in carrier loading status reports, in particular in heterogeneous networks (aka HetNets), and further particular in those deploying an extension carrier.

Background Mobile communication is constantly making progress. Under one aspect of such progress, heterogeneous networks (HetNets) are being investigated to improve coverage and, in general, performance.

General technical details of such Het et scenarios, e.g. under LTE™ and adopted communication protocols are publicly available. A repeated detailed description of each such property/functionality of the known LTE™ system is considered dispensable as those skilled in the pertinent art of technology will readily understand the description as given herein. Examples of the present invention exploit those basic properties and at least in aspects modify the functionality so as to obtain the advantages of at least some embodiments of the present invention.

Those HetNets comprise network transceiver devices or, more general, network entities providing different, and at (east partially overlapping coverage for communication, and those are simultaneously in operation. A typical example, when applying LTE™ terminology, of such networks entities reside in general in evolved NodeBs (eNB's), such as a macro eNB (of "large" coverage) and pico or femto eNBs or even remote radio heads ( H) (of "small" coverage when compared to the macro eNB's coverage).

Terminals such as user equipments UE are present within the coverage of both entities and may experience interference due to the network entities operating on neighboring or even identical bandwidth partitions or (physical) channels. In this regard, a macro cell or macro eNB which typically transmits using higher transmission power can be regarded as a source of interference, and is thus referred to herein also as "aggressor cell". On the other hand, a pico cell or pico eNB, more particularly the terminals camping in its coverage, experience the interference and are thus "victims". Hence not only those UEs but also those pico/femto eNBs / cells are also referred to herein as "victim cell". Note that a physical channel carries plural logical channels such as one or more payload channels and one or more control channels, in uplink and/or downlink, which are distributed within a channel's physical resources.

A channel's physical resources are defined in time and frequency domain. As an example, it is referred to LTE™, where a smallest unit is named a resource element RE. A RE carries in time domain one (QPSK modulated) symbol and has a corresponding duration, while in frequency domain it covers a bandwidth of one subcarrier. A plurality of 7 symbols in time domain constitute 1 slot of 0.5 ms duration, 2 slots constitute 1 subframe of 1 ms duration, and 20 slots (10 subframes) constitute one radioframe of 10 ms duration. A group of resource elements covering one slot in time domain and 12 subcarriers in frequency/bandwidth domain is referred to as physical resource block P B. A physical channel in general comprises one or more PRBs in bandwidth, but may also be definable as comprising a fraction (non-integer multiple) of one or more PRBs, in an extreme also as being represented by a single subcarrier only.

Further, in e.g. the case of LTE™, a group of 4 symbols is referred to as resource element group, REG. 9 REGs and thus 36 resource elements RE in turn constitute for example a control channel element CCE to which a PDCCH message is mapped. Note that resource elements of REGs and REG's of a CCE do not need to be adjacent to each other in time/frequency domain but can be distributed at distinct physical locations within a time/frequency resource grid of REs; they are thus at least logically linked to each other. In heterogeneous network deployment, a combined usage of enhanced inter-cell interference coordination (elCIC) and cell range expansion (CRE) is effective for improving the system and cell-edge throughput. With elCIC, a macro cell (or macro eNB) utilizes so-called almost blank subframes (ABS) with zero transmission power mainly in physical downlink control channel or physical downlink shared channel (PDCCH/PDSCH) to mitigate the interference to the pico user equipments (UEs) (those UEs camping in the coverage of the pico eNB) with CRE. Furthermore, the Resource Status mechanism enables a pico eNB to provide information in order to "aid the macro eNB designating ABS to evaluate the need for modification of the ABS pattern" , as for example described in 3GPP TS 36.423 (36.423-a20). It means that the macro eNB determines the ABS pattern adjustment based on the DL ABS status information. Moreover, in the recent discussion of 3GPP (3^rd Generation Partnership Project), low power ABS (LP-ABS) (also known as reduced power ABS or non-zero power ABS) is suggested to tradeoff the performance loss of an aggressor cell that is incurred when pure ABS (i.e. zero power ABS (ZP-ABS)) is employed. By using LP-ABS, some subframes in the previous ABS pattern are allowed to transmit data with a low transmission power in PDCCH/PDSCH etc., to serve the aggressor cell center UE with the acceptable performance while less interference to victim cell UEs.

On the other hand, a new carrier type of an "extension carrier" is discussed for carrier aggregation (CA) deployment scenarios. One of the main target scenarios for further enhancement of CA in Rel-11 could be a HetNet deployment scenario with macro cell plus local area (LA) small (such as pico, femto, relay or RRH) cells. One use case of the additional carrier type, i.e. the extension carrier, will be to deploy it in such small cell areas to facilitate inter-cell interference coordination (ICIC) between the macro-cell and small cells by applying "complete" blank subframes even without transmitting a cell-specific reference signal (CRS) and the PDCCH. Such a blank subframe or radio resource features without CRS and PDCCH transmissions are also beneficial in reducing inter-cell interference in dense local area deployments with fractional traffic loads and in achieving energy efficient operation in small cells.

However, it is not agreed on how to judge whether such extension carrier should be activated/deactivated, and what is the appropriate number of the extension carriers is also still not explored, for example. 12 076608

In the time domain based elCIC, it was agreed e.g. in 3GPP TS 36.423 that a new information element IE called "DL ABS Status IE" shall be included in the resource status update message, to reflect a resource usage indication allocated to the UEs protected by ABSs. Based thereon, the macro eNB can determine whether the protected resources are effectively utilized or not, and do the corresponding measurement. However, it is targeted for the time domain ICIC, but not for the frequency domain in regard of a usage of CA and/or extension carriers.

In fact, when the extension carrier is employed to combat the inter- cell interference, there are the following example cases on the carrier allocation and adjustment.

a) Given that any component carrier can be configured as extension carrier. When a carrier is added/reduced, what kind of carrier

(extension carrier or ordinary carrier) should it be activated/deactivated as?

b) Given that there are two component carrier sets, which is respectively extension carrier set and the ordinary carrier set. When a carrier is needed to be activated or deactivated, which carrier set should it be selected from or returned to?

c) If all the carrier resource has been fully utilized and the available protected carrier resources at the aggressor cell and victim cell are heavily loaded, how can the aggressor cell make an appropriate decision for the optimum allocation between extension carrier and ordinary carrier to maximize the performance overall the system?

If we use the carrier loading status to represent the actual carrier utilization by UEs that need protection, DL ABS status as adopted/proposed in 3GPP TS 36.423 in the current specification, known as the P B utilization ratio in the protected resource, is unable to reflect the carrier loading status of an extension carrier, for example.

This is mainly attributed to the fact that cross carrier scheduling is usually employed with multiple component carriers available, and consequently, for the UEs that need protection, PDSCH transmission can be done over any component carrier rather than only in the protected carrier (for which ABS are applied). It is possible that PDCCH transmission of an extension carrier is over burdened, while PDSCH transmission can still be satisfactorily via cross carrier scheduling.

Therefore, it may not make sense to derive the carrier loading status via PRB utilization ratio in the protected carrier.

Since inherent to those mechanisms or solutions there are still issues to be solved, irrespective of the pre-existing proposals outlined above, there is still a need to further improve such systems. Summary

Various aspects of examples of the invention are set out in the claims.

According to an aspect of the present invention, there is provided, e.g. in relation to a so-called victim eNB ,

an apparatus as defined in claim 1,

an apparatus as defined in claim 13, and

a method as defined in claim 23. According to a further aspect of the present invention, there is provided, e.g. in relation to so-called aggressor eNB, an apparatus as defined in claim 33,

an apparatus as defined in claim 46, and

a method as defined in claim 57. Advantageous further developments of each such aspect are set out in respective dependent claims.

According to a further aspect of the present invention, as set out in claims 68 and 69, respectively, there are provided computer program products comprising respective computer-executable components which, when the program is run on a computer, are configured to perform the above method aspects according to the independent as well as respective dependent claims, respectively. That is, such computer program products also encompass computer readable storage media comprising a set of computer-executable instructions which, when the program is run on a device (or on a processor or processing unit thereof which may be part of a controller or control unit or control module), such as a network transceiver device eNB and its processor, cause the device to perform the method aspects. In particular, the above computer program product/products may be embodied as a computer-readable storage medium. Accordingly, under at least some example aspects of this invention, improvements are achieved in that

- there are applied some considerations on the resource status information of a victim cell toward an aggressor cell to select an appropriate carrier pattern and ABS/LP-ABS pattern;

- in this context it is in at least some examples explored the issue of the carrier loading status so as to facilitate an appropriate carrier allocation solution for the interference coordination in the HetNets with the extension carrier;

- some examples are given on how to determine the appropriate allocation of carrier allocation;

- at least in some examples there is a tight coordination of the aggressor cell eNB with the victim cell eNB, so that by virtue thereof the application of LP-ABS is enabled so as to maximize the aggressor cell performance while with the acceptable interference to the victim cell UEs;

- according to at least other examples, the exchange of carrier load status enables to provide for an appropriate number of extension carrier allocation and ABS/LP-ABS pattern, which consequently facilitate the scheduling of both the aggressor cell and victim cell;

- in at least example scenarios/embodiments, a new metrics or quantity is presented to be used for the victim cell's feedback to the aggressor cell so as to facilitate it for the aggressor cell to determine the appropriate carrier allocation, and ABS as well as LP-ABS pattern from the view of overall system performance. Additionally the following advantages can be named as example advantages for at least some example embodiments of the present invention:

- The new metrics "CCE utilization status" (or CCE occupation ratio) is able to reflect the control channel loading status of the extension carrier;

- If the reporting of the CCE utilization status is enabled (e.g. from victim eNB to aggressor eNB), it will support the aggressor cell/eNB to determine an appropriate carrier allocation, which consequently reduces the interference from the aggressor cell and improves the resource utilization overall the system; - In addition, the CCE utilization status feedback is beneficial to determine the optimum configuration of ABS as well as LP-ABS pattern in a system wherein the cross carrier scheduling is employed, which will contribute to an overall throughput improvement while minimizing the interference.

Some embodiments of the present invention can be applied to/embodied in relation to e.g. LTE™ radio access, or LTE™ -A radio access, in particular in e.g. modems and/or wireless devices and/or units and/or modules and/or chipsets thereof, in particular those related to/inserted in or insertable to network transceiver devices or network entities such as evolved Node B's, eNB's, whether macro eNBs or pico/femto eNBs, or RRHs or the like. Other standards (such as those defined in projects / by bodies named 2G, 3G, 4G, 3GPP, HSDPA, WCDMA, cdma2000, GSM, UMTS, IMS, 3GPP2, IEEE, IETF) may employ different names for those entities, but example embodiments may be equally applicable to those, e.g. NodeBs in UMTS or base stations BS in GSM, as long as those may be deployed in e.g. at least a similar HetNet scenario employing extension carriers and/or carrier aggregation.

Some aspects of the invention would be reflected by corresponding adaptations to standards such as at least LTE™ -A Rel. 11 and following, to an evolved UTRAN (Universal Telecommunication Radio Access Network), to an interface known as X2 interface between network entities, i.e. e.g. macro and pico/femto eNBs, to implementation of those eNBs, e.g. in terms of control/processing mechanisms adopted by those entities and services/features provided by those.

Brief description of drawings For a more complete understanding of some example embodiments of the present invention, reference is now made to the following descriptions taken in connection with the accompanying drawings in which:

Fig. 1 illustrates one example scenario and entities involved according to at least an example embodiment; and Fig. 2 illustrates one example of a flowchart according to at least an example embodiment of a processing as performed at a victim eNB;

Fig. 3 illustrates one example of a flowchart according to at least an example embodiment of a processing as performed at an aggressor eNB.

Description of example embodiments

Example aspects and/or at least some example embodiments of the invention will be described herein below.

Generally, some example embodiments of the invention are implemented in a framework of e.g. a telecommunication system which is suitable to use carrier aggregation, CA, and/or at least to make use of extension carriers and more particularly, at least some example embodiments of the invention affect network entities eNB (pico/femto as well as macro) operated within such a framework, e.g. in a HetNet environment.

As a mere example only, the description refers to such modules, units or apparatuses related to network entities, eNBs, which conform to the LTE™ standard and are arranged / configured for communication in e.g. kind of a carrier aggregation scenario, in which at least an extension carrier is enabled for use together with/in parallel to an "ordinary" channel. However, this does not preclude the use of other network entities comprising wireless communication modules/units achieving similar functionalities, or the use of other communication standards such as LTE™ -A and beyond, as long as extension carrier deployment is applied/applicable. Also, the bandwidth of wireless communication is not crucial for some example embodiments of the invention.

Transmissions are effected within (physical) resources such as resource elements RE of (one or more) physical resource blocks PRB. Signals (transmitted from the eNB and received at the UE) used for measurement / evaluation of the CoMP scenario are referred to as reference (signals or) symbols RS. Such reference symbols are assigned to (specific) physical resource elements RE within physical resource blocks PRB. Likewise, control elements are assigned to specific resources such as CCEs. An interrelation between REs, PRBs and the like was already defined above; hence a repeated definition is dispensed at this point.

Fig. 1 illustrates one example scenario and entities involved according to at least an example embodiment.

An eNB 1 is referred to as victim eNB and comprises at least a control unit 11 which controls, among other parts of the eNB such as a memory (not shown) storing data such as measurement data, processing data etc. as well as control code portions, a receiver/ transmitter unit 12 of the eNB. The Rx/Tx unit 12 is configured to provide one or more distinct carriers or channels, e.g. as extension carrier and/or in carrier aggregation CA. The channels are wirelessly transmitted via an antenna Ant_l (or multiple antennas) of the eNB which is configured for transmission to and reception from one or more terminals such as user equipments UE.

Similarly, an eNB 3 is referred to as aggressor eNB and comprises at least a control unit 31 which controls, among other parts of the eNB such as a memory (not shown) storing data such as measurement data, processing data etc. as well as control code portions, a receiver/ transmitter unit 32 of the eNB. The Rx/Tx unit 32 is configured to provide one or more distinct carriers or channels, e.g. as extension carrier and/or in carrier aggregation CA. The channels are wirelessly transmitted via an antenna Ant_3 (or multiple antennas) of the eNB which is configured for transmission to and reception from one or more terminals such as user equipments UE.

Similarly, a user equipment UE 2 is referred to as "victim" UE and comprises at least a control unit 21 which controls, among other parts of the UE such as a memory (not shown) storing data such as measurement data, processing data etc. as well as control code portions, a receiver/ transmitter unit 22 of the UE. The Rx/Tx unit 22 is configured to provide/communicate via one or more distinct carriers or channels, e.g. extension carrier and/or in carrier aggregation CA. The channels are wirelessly transmitted/received via an antenna Ant_2 (or multiple antennas) of the UE which is configured for transmission to and reception from one or more network entities, e.g. eNBl and/or eNB3.

Note that separate antennas may be provided at those devise/entities for reception and transmission, or that more than one antenna e.g. for multipoint transmission may be present. Plural UEs may be present in the coverage of the aggressor and victim eNBs, though only one is illustrated, Each of those UEs receives data in downlink DL (denoted by 5b) from the eNBs such as control data via a control channel, such as PDCCH, or other (control) data, for example via PDSCH. The UEs conduct measurements based on reference signals to evaluate signal quality and return measurement results in uplink UL (denoted by 5a) towards a network entity, e.g. an eNB. For example, a UE reports quantities/values such as S P, RSRQ, RSSI, channel quality indication (CQI), ... to a eNB, e.g. eNB 1 as shown in Fig. 1.

In the illustrated example scenario, eNBl and eNB3 are connected for signaling exchange via an interface denoted by numeral 4 such as X2 interface. That interface need not to be a wireless interface but can be a wired interface or over the air (OTA) interface. At least eNBl (victim) signals/reports via this interface, at least according to an example embodiment, a carrier load status represented e.g. by a CCE occupation ratio to the eNB 3 (aggressor). eNB 3 may signal via the X2 interface 4 a processing result to the eNB 1 such as a carrier pattern to be applied for the transmission of the UEs, e.g. UE 2 and others (not shown), in terms of applying ABS, LP-ABS, or the like, which eNB 1 then informs to the UEs. For the purposes of the present description of at least some example embodiments, it is assumed/defined that "clear channel / clear carrier" represents a carrier/channel that is configured as ordinary carrier at victim cell eNBl, while the same carrier/channel is configured as extension carrier at aggressor cell eNB 3, and eNB 3 denotes the aggressor cell eNB and eNB 1 denotes the victim cell eNB. Note that extension carrier is just for illustration. Alternatively it can be any PDCCH protected carrier (which is protected in that it shall be kept "clear" of interference).

Thus, bearing this assumption in mind and in view of the example scenario / architecture described in Fig. 1, it will be understood that in terms of a general level of at least some example aspects of the invention, the victim cell (eNB 1) reports carrier loading status including the information of CCE occupation of the clear carrier to the aggressor cell (eNB3). Reporting is performed according to predefined rules. The aggressor cell (eNB 3) integrates these addressed factors along with the local information available to it and determines whether to activate/deactivate the extension carrier or whether to switch between extension carrier and ordinary carrier. Optionally or additionally, it determines as well the ratio of ABSs/LP-ABSs to be used (for / by the UEs in the coverage of the victim cell eNBl, to which this information is sent). One or more of those determinations or actions can be beneficial, for example, to maximize the system performance in terms of overall throughput and QoS level, in order to mention at least some of advantages that can be obtained by virtue of one or another example embodiment of the invention.

Thus, the victim eNB (eNB 1) differentiates or classifies its served UE as the strongly interfered UE and moderately interfered UE as well as the weakly interfered UE by the aggressor eNB 3 according to certain rules, e.g., based on one or more feedback signals such as the RSRP or RSRQ received in feedback by each pico UE. In principle, those weakly interfered UEs are instructed, by the victim eNB (eNB 1) (based on corresponding signal received from the aggressor eNB 3) to transmit in non-ABS of ordinary carrier (i.e. clear channel), the medium interfered UEs to transmit in LP-ABS of clear carrier, the strongly interfered UEs shall transmit in ABS of clear carrier. Under at least one example aspect of the invention, a new metric or quantity is proposed to be defined, namely a metric named e.g. "CCE ratio" or "CCE occupation ratio", which indicates the percentage of control channel resource blocks of clear channel (as used by plural UEs having a respective common interference classification):

For example:

CCE occupation 1 is equal to the CCE number of strongly interfered UEs / all the available CCE number in the clear carrier;

CCE occupation 2 is equal to the CCE number of medium interfered UEs / all the available CCE number in the clear carrier.

More than two classifications are possible, at least one should be provided, e.g. "interfered" vs. "weak"/non-interfered, while within "interfered" various levels of interference strength or class can be defined (in the example above 2: strong and medium). For example those could be "extremely strong", "very strong", "strong", "medium high", "medium", "medium low" as compared to weak/ non-interfered ones, or a subset thereof or even more.

All the available CCE number can be of two options:

a) The available CCE number in all the subframes within a predefined time, e.g., within one or more radio frames;

b) The available CCE number in the subframes excluding those subframes with CRS configuration, optionally also within a predetermined time.

When there are multiple "clear carriers" or "clear channels" (to be kept "clear" from interference from a coexisting extension channel/carrier at another eNB (the aggressor)), the defined metric may be an average percentage value of all the clear carriers, or a separate indication for each unique clear channel.

From a procedural aspect, according to example embodiments, the following procedure could be adopted, while of course modifications are possible.

The eNB 1 (victim) classifies the terminals UE in its coverage based on their reported feedback signals, e.g. RSRP, RSSI, RSRQ or the like. Then, at some time, the victim eNB 1 is triggered to report CCE occupation of the classified UEs. The victim eNB 1 knows about the UEs served and the control channel elements CCE allocated to a respective UE. Hence, based on the CCEs per UE and the interference classification determined for each UE, the eNB 1 can determine the CCE occupation ratio for each class of interference.

Based on this indication of classification(s) which is signalled to the aggressor, eNB 3, that macro eNB determines which measures to initiate to reduce interference on the carrier (which is an ordinary carrier at the victim but an extension carrier at the aggressor), e.g. whether to activate/deactivate the extension carrier or to switch the carrier between ordinary and extension carrier. Reporting from victim to aggressor can be triggered by the eNB 1 periodically or aperiodically based on some predefined events, e.g. upon the CCE occupationl and/or 2 is higher or lower than some predetermined thresholds. Note that measures (to be) initiated are for example represented by certain configurations, e.g. carrier configurations and/or power (zero power/low power) configurations of (sub-) frames. The aggressor eNB 3, based thereon, shall make a decision on whether to enable/disable the extension carrier to maximize the system throughput, for example.

Various criteria may be applicable for such decision, at least some examples are given below:

- When the sum of CCE occupation 1 + CCE occupation ratio 2 exceeds a predetermined threshold η , aggressor eNB 3 shall consider to add the extension carrier, since the control channel resource is over burdened, and vice versa. The adding operation may reside in activating a new carrier or to change a carrier configuration; for example: in a scenario in which the eNB3 is utilizing component carrier (CC) 1 and 2 as the normal carrier(s), and CC3 as the extension carrier; after receiving the CCE overburden indication, it will activate a new carrier CC4 as extension carrier or change e.g. one of the normal carriers CC1 or CC2 to become an extension carrier;

- The aggressor eNB 3 shall initiate to adjust the allocation of ABS/LP-ABS to be applied by the victim UEs, e.g. via signaling to the victim eNB, e.g. adjust allocation of ABS/LP-ABS proportional to the CCE occupation 1 and/or 2 respectively:

For example, according to an example related to such aspect:

When CCE occupation 1 (strong interference) exceeds a predefined threshold ¾ , eNB 3 shall consider to add more ABS in the clear carrier, and vice versa;

When CCE occupation 2 (medium interference) exceeds a predefined threshold eNB 3 shall consider to add more LP-ABS in the clear carrier, and vice versa.

There may be multiple interference levels (r)2a, r|2b, ...) which consequently result in multiple amounts of ABS subframes to be used and the corresponding ABS patterns; likewise there may be multiple interference levels (n.3a, p3b, ...), which consequently result in multiple LP-ABS power levels (power level 3a, 3b, ...) and the corresponding LP-ABS patterns.

The aggressor eNB 3 may signal the carrier pattern through adding an additional bit in EARFCN to indicate whether it is used as extension carrier or not; the eNB 3 may also signal the new carrier pattern, ABS subframe pattern as well as the LP-ABS subframe pattern through different carrier bitmap or subframe bitmap. Other examples than the above may be chosen for the information transfer in this regard. For the remaining subframes of the extension carrier that are not allocated as ABS or LP-ABS, eNB 3 may utilize those via cross-carrier scheduling or enabling e-PDCCH for the normal data transmission;

The eNB 1, upon receiving the notification, may adopt the new carrier pattern, ABS/LP-ABS pattern, e.g. after another predefined timer negotiated between aggressor eNB 3 and victim eNB 1. The eNB 1 may adopt the marked extension carrier of eNB 3 as the ordinary carrier to get a more clear (less interfered) carrier when it acquires new carrier pattern.

In summary, according to some example aspects of the invention as indicated above, it is proposed to determine, based on a CCE utilization status (CCE occupation ratio), to determine the allocation of ordinary carrier and extension carrier among all the available carrier, as well as to determine a ABS/LP-ABS pattern, and further to exchange this information, e.g. semi-statically, to facilitate an optimum resource utilization. Aspects of the present invention were described herein above on a rather general level. Merely for the purpose of giving a more concrete example, going into some technical implementation details, in terms of the example aspect of transmitting the CCE occupation ratio from the victim eNB to the aggressor eNB, some examples of the present invention encompass to enable

- to add that new IE in the ABS status according to TS36.423 (example 1)

- to add that new IE in the load information (example 2),

- to add the new information element IE into a newly defined message (example 3)

Those examples are shown herein below including the message fields and the new fields and a brief description thereof. Example 1 :

Already in TS 36.423, the ABS Status IE is used to aid the eNB designating ABS to evaluate the need for modification of the ABS pattern, so the proposed new information element CCE occupation ratio is proposed to be added in the ABS status message, as for example shown below.

IE/Group Name Presence Range IE type and Semantics description reference

DL ABS status M INTEGER (0..100) Percentage of ABS resource allocated for UEs protected by ABS from strong inter- cell interference. The denominator of the percentage calculation is indicated in the Usable ABS Information.

CCE occupation 1 o INTEGER f0..100) Percentaae of CCE

resource utilized bv stronqlv interfered UEs in the CRE zone. The denominator of the Dercentaae calculation mav be either the available CCE number of all the subframes or that in the subframes excluding CRS configurated.

CCE occuoation 2 0 INTEGER (0..100) Percentaae of CCE

resource utilized bv medium interfered UEs in the CRE zone. The denominator of the percentaae calculation mav be either the available CCE number of all the subframes or that in the subframes excluding CRS configurated.

Example 2:

The proposed new information element CCE occupation ratio proposed to be added in the load information message, as example shown below.

Example 3:

The proposed new information element CCE occupation ratio is proposed to be added in a new information message, as for example shown below.

Various aspects of the present invention have been described herein above, on a general as well as on a specific implementation oriented level.

Now, a brief description of a processing from the victim elMBs perspective will be given with reference to the flowchart of Fig. 2.

The victim eNB, numeral 1 in Fig. 1, comprises an apparatus which comprises a control unit or controller, numeral 11 in Fig. 1, which is configured to perform such processing, e.g. based on code portions stored in a memory, when executed in a processor of the control unit. The process starts in a step S20. In this regard, then, the victim eNB and/or the apparatus thereof in step S21 receives a feedback (FB) signal indicative of a communication channel quality from at least one terminal, the at least one terminal communicating on a respective physical channel, the physical channel being a communication channel of the apparatus and of another entity.

In a step S22, at last one, or even each, terminal is classified, based on the respective feedback signal, into one of at least two interference classes.

In a step S23 it is derived, for at least one interference class, an indication of occupation of the respective channel by the terminals of the respective class. Such deriving of the indication of occupation of the respective channel by the terminals of the respective class can be accomplished as a ratio of control channel resources of the respective channel used by the terminals of the respective class, divided the entirety of available control channel resources, for example. For such deriving, the entirety of available control channel resources can be set /defined as the overall number of control channel elements for all subframes of a channel within a predefined time, or as the overall number of control channel elements for all subframes of a channel within a predefined time reduced by the number of control channel elements of cell specifically configured subframes. Optionally, it is possible to calculate, for at least one interference class, an average indication of occupation based on the indication of occupation of all respective channels of the respective class, and to report the average.

In a step S24, it is reported the at least one indication of occupation of the respective channel by the terminals of the respective class to a network entity. The reporting can be accomplished by transmitting the report via an X2 interface I/F to the network entity. The reporting of the at least one indication of occupation can happen periodically, or aperiodically, e.g. triggered based on the occurrence of a specific event, wherein the triggering for the reporting for the specific event can be that at least one of the at least one indication of occupation exceeds a respective threshold .

The processing ends in a step S25, or returns to step S21, e.g . after a specific period or upon a triggering event.

Now, a brief description of a processing from the aggressor e Bs perspective will be given with reference to the flowchart of Fig. 3.

The aggressor eNB, numeral 3 in Fig. 1, comprises an apparatus which comprises a control unit, numeral 31 in Fig. 1, which is configured to perform such processing, e.g. based on code portions stored in a memory, when executed in a processor of the control unit. The process starts in a step S30.

In this regard, then, in a step S31, the aggressor eNB and/or the apparatus, i.e. a control unit or controller thereof receives, for at least one interference class, an indication of occupation of a respective physical channel by (one or more) terminals of the respective class. The indication is associated to a respective physical channel, the physical channel being a communication channel of the apparatus and of another entity (i.e. the victim eNB) . The at least one indication of occupation of the respective channel by terminals of the respective class is received from a network entity, e.g. received as report via an X2 interface from the network entity. In a step S32, it is decided on measures to initiate in order to reduce interference for said physical channel used by the apparatus and the another entity, The deciding is based on the indication of occupation received for at least one interference class.

This deciding encompasses to decide on measures to reduce interference in that it initiates at least one of the following : deactivating the physical channel, switching a role of the physical channel, activating a new physical channel, modifying a channel configuration.

Further, such deciding on the measures to reduce interference is based on respective limit values that are defined such that there is defined at feast one limit value per indication of occupation, and/or per sum of plural indications of occupation, to determine that at least one of the respective limit values is reached or exceed. Responsive thereto, triggering of an initiation of at least one of the measures or configurations to reduce interference, for example, is performed. Finally, in a step S33, the another entity is informed of the respective measures initiated, so as to accordingly adapt its own behavior.

Under further individual example aspects, in this regard, in an apparatus, e.g. of the aggressor eNB, the configuration is one of a normal carrier and extension carrier configuration based on the sum of plural indications of occupation, or an almost blank subframes ABS or low power almost blank subframes LP-ABS configuration based on per indication of occupation by different classified UE, respectively. The controller of such apparatus is further configured to cause to inform the another entity of the respective configuration decisions initiated. For example, the controller is further configured to cause to inform the another entity of the carrier configuration decisions through adding an additional bit in an Evolved Universal Terrestrial Radio Access ,E-UTRA, Absolute Radio Frequency Channel Number , EARFCN, to indicate whether a component carrier is used as extension carrier or not at the entity. For example, the controller is further or alternatively configured to cause to inform the another entity of the carrier configuration decisions through a carrier bitmap. The controller is further configured to cause to instruct an operation administration and maintenance entity, OA , to establish the mapping between the component carriers and the specified bit in the bitmap.

Still further, in regard to such apparatus, the controller is further configured to cause to inform the another entity of the LP-ABS configuration decisions through the respective subframe bitmap differentiating between a ABS bitmap and optionally a specific power level indication based on the ABS bitmap. For example, the apparatus comprises an evolved NodeB or base station, wherein the apparatus is configured for use in an LTE™ or LTE™-A system, or other system. The processing ends in a step S34, or returns to step S31, e.g. after a specific period or upon a triggering event that made the victim el\IB send another indication of occupation report.

It is still to be noted that some embodiments of the invention may be implemented in software, hardware, application logic or a combination of software, hardware and application logic. The software, application logic and/or hardware generally reside on control modules or modems, in general circuitry. In an example embodiment, the application logic, software or an instruction set is maintained on any one of various conventional computer-readable media. In the context of this document, a "computer-readable medium" may be any media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer or smart phone, or user equipment.

As used in this application, the term 'circuitry' refers to all of the following :

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) to combinations of circuits and software (and/or firmware), such as (as applicable):

(i) to a combination of processor(s) or

(ii) to portions of processor(s)/software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or user equipment or any other terminal, or network entity such as a server, to perform various functions) and

(c) to circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that 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 (terminal) or a similar integrated circuit in server, a cellular network device, or other network device.

That is, it can be implemented as/in chipsets to such devices, and/or modems or apparatuses or units thereof. If desired, the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the above-described functions may be optional or may be combined. Although various aspects of the invention are set out in the independent claims, other aspects of the invention comprise other combinations of features from the described embodiments and/or the dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the claims. It is also noted herein that while the above describes example embodiments of the invention, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications which may be made without departing from the scope of the present invention as defined in the appended claims.

List of acronyms:

DL Downlink

UL Uplink

eNB Enhanced Node B.

UE User Equipment

Tx Transmit

Rx Receive

LTE™ Long Term Evolution

PDCCH Physical Downlink Control Channel

PDSCH Physical Downlink Shared Channel

ICIC Inter-Cell Interference Coordination

elCIC Enhanced Inter-Cell Interference Coordination

CRE Cell Range Expansion

ABS Almost Blank Subframe

LP-ABS Low Power Almost Blank Subframe

ZP-ABS Zero Power Almost Blank Subframe

CCE Control Channel Element

RRH Remote Radio Head

CRS Cell-specific Reference Signal

EARFCN E-UTRA Absolute Radio Frequency Channel Number

E-UTRA Evolved Universal Terrestrial Radio Access

CA Carrier Aggregation

LA Local Area

IE Information Element

CC Component Carrier PRB Physical Resource Block

RSRP Reference Signal Received Power

RSRQ Reference Signal Received Quality

RSSI Received Signal Strength Indicator

3GPP 3^rd Generation Partnership Project

OAM Operation Administration and Maintenance

2G/3G/4G 2^nd/3^rd/4^th Generation

HSDPA High Speed Digital Packet Access

WCDMA Wideband Code Divisional Multiple Access

cdma2000 Code Divisional Multiple Access 2000

GSM Global System of Mobile Communication /

Groupe Special Mobile

UMTS Universal Mobile Telecommunication System

IMS IP Multimedia Subsystem

IP Internet Protocol

IEEE Institute of Electrical and Electronics Engineers

IETF Internet Engineering Task Force

Claims

WHAT IS CLAIMED IS:

1. An apparatus, comprising:

a controller configured to

receive a feedback signal indicative of a communication channel quality from at least one terminal, the at least one terminal communicating on a respective physical channel, the physical channel being a communication channel of the apparatus and of another entity,

classify each terminal, based on the respective feedback signal, into one of at least two interference classes,

derive, for at least one interference class, an indication of occupation of the respective channel by the terminals of the respective class.

2. An apparatus according to claim 1, wherein

the controller is further configured to

cause transmission of a report of the at least one indication of occupation of the respective channel by the terminals of the respective class in the communication channel to a network entity.

3. An apparatus according to claim 2, wherein

the controller is further configured to

cause transmission of the report via an inter network entity interface to the network entity.

4. An apparatus according to claim 2 or 3, wherein

the controller is further configured to

cause transmission of the report of the at least one indication of occupation periodically.

5. An apparatus according to claim 2 or 3, wherein

the controller is further configured to

cause transmission of the report of the at least one indication of occupation aperiodically based on the occurrence of a specific event.

6. An apparatus according to claim 5, wherein

the controller is further configured to

trigger the reporting for the specific event that at least one of the at least one indication of occupation exceeds a respective threshold.

7. An apparatus according to claim 1, wherein

the controller is further configured

to derive the indication of occupation of the respective channel by the terminals of the respective class

as a ratio of control channel resources of the respective channel used by the terminals of the respective class, divided the entirety of available control channel resources in the communication channel.

8. An apparatus according to claim 7, wherein

the controller is further configured

to set the entirety of available control channel resources as the overall number of control channel elements for all subframes of a channel within a predefined time.

9. An apparatus according to claim 7, wherein

the controller is further configured

to set the entirety of available control channel resources as the overall number of control channel elements for all subframes of a channel within a predefined time reduced by the number of control channel elements of cell specifically configured subframes.

10. An apparatus according to claim 1, wherein

the controller is further configured

to calculate, for at least one interference class, an average indication of occupation based on the indication of occupation of all respective channels of the respective class, and to report the average.

11. An apparatus according to any of the preceding claims, wherein the apparatus comprises an evolved NodeB or base station.

12. An apparatus according to any of the preceding claims, wherein the apparatus is configured for use in an LTE™ or LTE™-A system.

13. An apparatus, comprising:

a controller means comprising

means for receiving a feedback signal indicative of a communication channel quality from at least one terminal, the at least one terminal communicating on a respective physical channel, the physical channel being a communication channel of the apparatus and of another entity,

means for classifying each terminal, based on the respective feedback signal, into one of at least two interference classes,

means for deriving, for at least one interference class, an indication of occupation of the respective channel by the terminals of the respective class.

14. An apparatus according to claim 13, wherein

the controller means further comprises means for causing transmission of a report of the at least one indication of occupation of the respective channel by the terminals of the respective class in the communication channel to a network entity.

15, An apparatus according to claim 14, wherein

the controller means further comprises

means for causing transmission of the report via an inter network entity interface to the network entity.

16. An apparatus according to claim 14 or 15, wherein

the controller means further comprises

means for causing transmission of the report of the at least one indication of occupation periodically.

17. An apparatus according to claim 14 or 15, wherein

the controller means further comprises

means for causing transmission of the report of the at least one indication of occupation aperiodically based on the occurrence of a specific event.

18. An apparatus according to claim 17, wherein

the controller means further comprises

means for triggering the reporting for the specific event that at least one of the at least one indication of occupation exceeds a respective threshold.

19. An apparatus according to claim 13, wherein

the controller means further comprises

means for deriving the indication of occupation of the respective channel by the terminals of the respective class as a ratio of control channel resources of the respective channel used by the terminals of the respective class, divided the entirety of available control channel resources in the communication channel.

20, An apparatus according to claim 19, wherein

the controller means further comprises

means for setting the entirety of available control channel resources as the overall number of control channel elements for all subframes of a channel within a predefined time.

21. An apparatus according to claim 19, wherein

the controller means further comprises

means for setting the entirety of available control channel resources as the overall number of control channel elements for all subframes of a channel within a predefined time reduced by the number of control channel elements of cell specifically configured subframes.

22. An apparatus according to claim 13, wherein

the controller means further comprises

means for calculating, for at least one interference class, an average indication of occupation based on the indication of occupation of all respective channels of the respective class, and to report the average.

23. A method, comprising:

receiving a feedback signal indicative of a communication channel quality from at least one terminal, the at least one terminal communicating on a respective physical channel, the physical channel being a communication channel of the apparatus and of another entity,

classifying each terminal, based on the respective feedback signal, into one of at least two interference classes,

deriving, for at least one interference class, an indication of occupation of the respective channel by the terminals of the respective class.

24. A method according to claim 23, further comprising

causing transmission of a report of the at least one indication of occupation of the respective channel by the terminals of the respective class in the communication channel to a network entity.

25. A method according to claim 24, further comprising

causing transmission of the report via an inter network entity interface to the network entity.

26. A method according to claim 24 or 25, further comprising

causing transmission of the report of the at least one indication of occupation periodically.

27. A method according to claim 24 or 25, further comprising

causing transmission of the report of the at least one indication of occupation aperiodically based on the occurrence of a specific event.

28. A method according to claim 27, further comprising

triggering the reporting for the specific event that at least one of the at least one indication of occupation exceeds a respective threshold .

29. A method according to claim 23, further comprising

deriving the indication of occupation of the respective channel by the terminals of the respective class

30. A method according to claim 29, further comprising

setting the entirety of available control channel resources as the overall number of control channel elements for all subframes of a channel within a predefined time.

31. A method according to claim 29, further comprising

setting the entirety of available control channel resources as the overall number of control channel elements for all subframes of a channel within a predefined time reduced by the number of control channel elements of cell specifically configured subframes.

32. A method according to claim 23, further comprising

calculating, for at least one interference class, an average indication of occupation based on the indication of occupation of all respective channels of the respective class, and to report the average.

33. An apparatus, comprising :

a controller configured to

receive, for at least one interference class, an indication of occupation of a respective physical channel by terminals of the respective class, the indication being associated to a respective physical channel, the physical channel being a communication channel of the apparatus and of another entity,

decide on configurations to reduce interference for said physical channel used by the apparatus and the another entity based on the indication of occupation received for at least one interference class.

34. An apparatus according to claim 33, wherein

the controller is further configured to

receive the at least one indication of occupation of the respective channel by terminals of the respective class from a network entity.

35. An apparatus according to claim 34, wherein

the controller is further configured to

receive the report via an inter network entity interface from the network entity.

36. An apparatus according to claim 33, wherein

the controller is further configured to

decide on configurations to reduce interference in that it initiates at least one of the following :

deactivating the physical channel,

switching a role of the physical channel,

activating a new physical channel,

modifying a channel configuration.

37. An apparatus according to claim 36, wherein

the controller is further configured to

decide on the configurations to reduce interference

based on respective limit values that are defined such that

there is defined at least one limit value per

indication of occupation, and/or

per sum of plural indications of occupation, to determine that at least one of the respective limit values is reached or exceed, and

responsive thereto,

to trigger initiation of at least one of the configurations to reduce interference.

38. An apparatus according to claim 37, wherein

the configuration is one of a

normal carrier and extension carrier configuration based on the sum of plural indications of occupation, or

an almost blank subframes ABS or low power almost blank subframes LP-ABS configuration based on per indication of occupation by different classified UE, respectively.

39. An apparatus according to claim 36, wherein

the controller is further configured to

cause to inform the another entity of the respective configuration decisions initiated.

40. An apparatus according to claim 39, wherein

the controller is further configured to cause to inform the another entity of the carrier configuration decisions

through adding an additional bit in an Evolved Universal

Terrestrial Radio Access ,Ε-UTRA, Absolute Radio Frequency Channel

Number , EARFCN, to indicate whether a component carrier is used as extension carrier or not at the entity.

41. An apparatus according to claim 39, wherein

the controller is further configured to cause to inform the another entity of the carrier configuration decisions through a carrier bitmap.

42. An apparatus according to claim 41, wherein

the controller is further configured to cause to instruct an operation administration and maintenance entity, OA , to establish the mapping between the component carriers and the specified bit in the bitmap.

43. An apparatus according to claim 41, wherein

the controller is further configured to

cause to inform the another entity of the LP-ABS configuration decisions through the respective subframe bitmap differentiating between a ABS bitmap and optionally a specific power level indication based on the ABS bitmap.

44. An apparatus according to any of the preceding claims 33 - 43, wherein the apparatus comprises an evolved NodeB or base station.

45. An apparatus according to any of the preceding claims 33 - 44, wherein the apparatus is configured for use in an LTE™ or LTE™-A system .

46. An apparatus, comprising:

a controller means comprising

means for receiving, for at least one interference class, an indication of occupation of a respective physical channel by terminals of the respective class, the indication being associated to a respective physical channel, the physical channel being a communication channel of the apparatus and of another entity,

means for deciding on configurations to reduce interference for said physical channel used by the apparatus and the another entity based on the indication of occupation received for at least one interference class.

47. An apparatus according to claim 46, wherein

the controller means further comprises

means for receiving the at least one indication of occupation of the respective channel by terminals of the respective class from a network entity.

48. An apparatus according to claim 47, wherein

the controller means further comprises

means for receiving the report via an inter network entity interface from the network entity.

49. An apparatus according to claim 46, wherein

the controller means further comprises

means for deciding on configurations to reduce interference in that it initiates at least one of the following:

deactivating the physical channel,

switching a role of the physical channel,

activating a new physical channel,

modifying a channel configuration.

50. An apparatus according to claim 49, wherein

the controller means further comprises

means for deciding on the configurations to reduce interference based on respective limit values that are defined

such that

there is defined at least one limit value per

indication of occupation, and/or

means for triggering, responsive thereto, initiation of at least one of the configurations to reduce interference.

51. An apparatus according to claim 50, wherein

the configuration is one of a

52. An apparatus according to claim 49, wherein the controller means further comprises

means for causing to inform the another entity of the respective configuration decisions initiated.

53. An apparatus according to claim 52, wherein the controller means further comprises

means for causing to inform the another entity of the carrier configuration decisions

through adding an additional bit in an Evolved Universal Terrestrial Radio Access ,E-UTRA, Absolute Radio Frequency Channel Number , EARFCN, to indicate whether a component carrier is used as extension carrier or not at the entity.

54. An apparatus according to claim 52, wherein the controller means further comprises

means for causing to inform the another entity of the carrier configuration decisions through a carrier bitmap.

55. An apparatus according to claim 54, wherein the controller means further comprises

means for causing to instruct an operation administration and maintenance entity, OAM, to establish the mapping between the component carriers and the specified bit in the bitmap.

56. An apparatus according to claim 54, wherein the controller means further comprises

means for causing to inform the another entity of the LP-ABS configuration decisions through the respective subframe bitmap differentiating between a ABS bitmap and optionally a specific power level indication based on the ABS bitmap.

57. A method, comprising:

receiving, for at least one interference class, an indication of occupation of a respective physical channel by terminals of the respective class,

the indication being associated to a respective physical channel, the physical channel being a communication channel of the apparatus and of another entity,

deciding on configurations to reduce interference for said physical channel used by the apparatus and the another entity based on the indication of occupation received for at least one interference class.

58. A method according to claim 57, further comprising

receiving the at least one indication of occupation of the respective channel by terminals of the respective class from a network entity.

59. A method according to claim 58, further comprising

receiving the report via an inter network entity interface from the network entity.

60. A method according to claim 57, further comprising

deciding on configurations to reduce interference in that it initiates at least one of the following:

deactivating the physical channel,

switching a role of the physical channel,

activating a new physical channel,

modifying a channel configuration.

61. A method according to claim 60, further comprising

deciding on the configurations to reduce interference

based on respective limit values that are defined such that

there is defined at least one limit value per

indication of occupation, and/or

responsive thereto,

triggering initiation of at least one of the configurations to reduce interference.

62. A method according to claim 61, wherein the configuration is one of a

63. A method according to claim 60, further comprising

causing to inform the another entity of the respective configuration decisions initiated.

64. A method according to claim 63, further comprising

causing to inform the another entity of the carrier configuration decisions

through adding an additional bit in an Evolved Universal

Terrestrial Radio Access ,E-UTRA, Absolute Radio Frequency Channel Number , EARFCN, to indicate whether a component carrier is used as extension carrier or not at the entity.

65. A method according to claim 63, further comprising

causing to inform the another entity of the carrier configuration decisions through a carrier bitmap.

66. A method according to claim 65, further comprising

causing to instruct an operation administration and maintenance entity, OAM, to establish the mapping between the component carriers and the specified bit in the bitmap.

67. A method according to claim 65, further comprising

causing to inform the another entity of the LP-ABS configuration decisions through the respective subframe bitmap differentiating between a ABS bitmap and optionally a specific power level indication based on the ABS bitmap.

68. A computer program product comprising computer-executable components which, when the program is run on a computer, are configured to perform the method aspect as defined in claims 23 to 32.

69. A computer program product comprising computer-executable components which, when the program is run on a computer, are configured to perform the method aspect as defined in claims 57 to 67.