WO2014110745A1

WO2014110745A1 - Apparatuses, methods and computer program products for evaluating channel quality

Info

Publication number: WO2014110745A1
Application number: PCT/CN2013/070558
Authority: WO
Inventors: Chunyan Gao; Jing HAN; Lili Zhang; Wei Hong; Haiming Wang
Original assignee: Broadcom Corp
Current assignee: Broadcom Corp
Priority date: 2013-01-16
Filing date: 2013-01-16
Publication date: 2014-07-24
Anticipated expiration: 2015-07-16

Abstract

Apparatuses, methods and computer program products for evaluating channel quality are provided. The apparatus comprises: a controller, configured to cause reception of data in a radio frame comprising at least a first and a second subframe set, wherein the data comprise reference signals of at least two reference signal types, cause verification of the presence of a first reference signal type per subframe set, and responsive to a failure of the verification, for the subframe set concerned, cause measurement of a reference signal of a second reference signal type in the subframe set in which the first reference signal type is not verified to be present.

Description

APPARATUSES, METHODS AND COMPUTER PROGRAM PRODUCTS FOR EVALUATING CHANNEL QUALITY

Field of the invention

The present invention relates to apparatuses, methods and computer program products configured to achieve enhancements in evaluating channel quality, e.g. in flexible TDD systems. That is, it is related to e.g. CQI enhancements in such flexible TDD systems.

Background

Mobile communication is constantly making progress. A typical scenario or environment in relation to a scenario to which some aspects of the present invention are applicable, is for example a scenario as applied in conjunction with e.g. the LTE™ (Long Term Evolution) or LTE-A™ (LTE- advanced) telecommunication standard. Some aspects at least can also be applicable to other wireless communication scenarios. According to such standard(s), a network transceiver device such as an evolved NodeB, eNB, communicates via control and payload channels with a terminal such as a user equipment UE.

According to one aspect of such progress, a goal is to achieve error free data transmission. To this end, data transmission from a network transceiver device such as an evolved NodeB, eNB, towards a terminal such as a user equipment, UE, is crucial. In order to allow for proper and error free data transmission and reception, an eNB transmits so-called reference signals and/or symbols to the UE. Various different reference signals/ symbols may be in use. The UE being in receipt of and thus aware of the reference signals/symbols, uses these reference symbols to estimate the channel, and is subsequently enabled to properly decode payload transmissions received via that channel. Such reference symbols are assigned to (specific) physical resource elements RE within physical resource blocks PRB. A resource element RE is represented by a certain time interval and a frequency (bandwidth) assigned to it within the frequency-time domain. A plurality (defined number) of resource elements in frequency / bandwidth domain form a physical resource block PRB (in frequency domain), and a plurality of PRBs are present within a channel. A Resource Element RE is the smallest unit of transmission resource in LTE, in both uplink (UL) and downlink (DL). A RE consists of 1 subcarrier in the frequency/bandwidth domain for a duration of 1 symbol, i.e. Orthogonal Frequency Division Multiplexing (OFDM) or Single Carrier - Frequency Division Multiplexing (SC-FDM) symbol in the time domain. A PRB in turn is thus a unit of transmission resources consisting of 12 sub-carriers (REs) in the frequency domain and 1 timeslot (0.5 ms) in the time domain.

According to LTE agreements, a radio frame comprises twenty such time- slots, while each time-slot normally consists of 7 OFDM symbols. Plural PRBs are grouped to a resource block group, RBG. On the other hand, a radio frame of 10ms duration, composed of 20 timeslots, also corresponds to 10 subframes of 1 ms each.

Allowing for asymmetric UL-DL allocations has been announced as one benefit of deploying TDD system. The asymmetric resource allocation in LTE TDD is realized by providing seven different sem i- statically configured uplink-downlink configurations. These allocations can provide (in uplink direction) between 40% and 90% of the DL subframes.

For TDD deployments in general, interference between UL and DL including both basestation-to-basestation and UE-to-UE interference needs to be considered. The DL-UL interference in a TDD network is typically handled by statically provisioning a guard period and adopting the same frame timing and uplink-downlink configuration practically in the entire network. However, in local area (LA) network, it may be of interest to consider different UL/DL allocations in the neighboring cells, since same DL/UL configuration may not match the traffic situation in different LA cells with a small number of users.

The main property as we consider for a LA network scenario is that the typical cell size is small comparing with a macro cell, and the number of UEs connected to each eNB (or access point, AP) in the network is not large. And also, LA network deployment maybe does not consider network planning and optimization. DL-UL interference is one obstacle to deploy flexible TDD LA network. Now, consider a TDD deployment scenario with each cell frame synchronized, but not switch point synchronized. In this case, if each cell chooses one TDD configuration from seven TDD configuration patterns defined, there is no DL-UL interference problem for subframe 0, 1, 2 and 5 since these subframes have fixed link direction in any of TDD configurations defined.

For other subframes, their link direction can change with TDD configuration, and there can be DL-UL interference depending on the TDD configuration adopted in neighboring cells. Then, in this description, the subframes like 0, 1, 2 and 5 which have fixed link direction are called fixed subframe, while other subframes are called flexible subframe for simplicity. It is to be noted that the fixed subframe and flexible subframe can change depending on the TDD configurations allowed to be adopted, e.g, if a network only supports TDD configurations 1 and 2, then subframes 0, 1, 2, 4, 5, 6, 7, 9 are all fixed subframes, while subframes 3 and 8 are flexible subframes which are set as UL in TDD configuration 1 and DL in TDD configuration 2.

Fig. 2 graphically illustrates a radioframe of ten subframes of index 0 to 9, respectively, in terms of the fixed subframes of index 0, 1, 2 and 5 and the potentially flexible remaining subframes of index 3, 4, 6 to 9. Flexible subframes are also denoted/labeled by "F", while the fixed subframes 0, 1, 2, 5 are fixedly allocated downlink (labeled "D") (index 0, 5), uplink (labeled "U") (index 2), or a special subframe (labeled "S") (index 1).

DL-UL interference in flexible subframes will degrade the SINR significantly. For data transmission in a flexible subframe, link adaptation and HARQ can help to adapt to the interference level, but for control signaling to be transmitted in the flexible subframe(s), it is more sensitive to the interference due to lack of HARQ, and it will further reduce the throughput.

In terms of control signaling, a PDSCH (Physical Downlink Shared Channel) and PDCCH (Physical Downlink Control Channel) or enhanced PDCCH, ePDCCH, for example, carry control information in downlink from an eNB to a terminal such as a UE. A feedback in uplink from the UE to the eNB consists of e.g. a rank indicator (Rl), a pre-coding matrix index (PMI) and a channel quality indicator (CQI) and hybrid automatic repeat requests HARQ. Such feedback is e.g. carried in a physical uplink control channel, PUCCH. Hence, the UE estimates the channel based on the received reference signals such as CSI-RS, selects rank and PMI and calculates the post-processing (after receiver) SINR (signal to interference plus noise ratio) and derives the CQI based on that. For TDD deployments in LTE Rel'11 or an earlier release, a same frame timing and same uplink-downlink configuration are deployed practically in the entire network. This is to avoid interference between UL and DL including both basestation-to-basestation and UE-to-UE interference. However, in local area (LA) network, it may be of interest to consider different UL/DL allocations in the neighboring cells, since same DL/UL configuration may not match the traffic situation in different LA cells with a small number of users; and, it is also desirable to make the DL-UL configuration more dynamic to adapt to the traffic status in each cell.

Due to such motivation, the Chinese Academy for Telecommunication and Technology, CATT, proposed a new working item, Wl, for Rel'12 on enhancements to Interference Management and Traffic Adaptation, elMTA, which is to find a solution to enable TDD UL-DL reconfiguration to adapt to the traffic variation, then improve the resource efficiency, power saving or traffic delay. Four different time scales for TDD DL-UL reconfiguration are under discussion, and different time scales provide different gain in terms of traffic adaptation. Though potential gain from the TDD DL-UL reconfiguration can be expected, it also brings some problems to be solved. Those include Signaling mechanism(s) for TDD UL-DL reconfiguration; HARQ timing in case of DL-UL reconfiguration; DL-UL interference handling.

One objective of the elMTA Wl is mentioned to reside in an agreement on the supported time scale together with the necessary signaling mechanism(s) for TDD UL-DL reconfiguration and a specification of the necessary (if any) enhancements for TDD UL-DL reconfiguration with the agreed time scale and signaling mechanism (s), e.g. a HARQ/scheduling timeline, RLM/RRM measurements, and/or CSI reporting. Then some enhancements will be unavoidable to make the system with flexible TDD reconfiguration work, and the enhancement will need to be standardized to make common understanding between eNB and UEs.

Cell synchronization is required by TDD network, however due to the introduction of DL-UL reconfiguration in each cell independently, there is now the TDD deployment scenario where each cell is frame synchronized, but not switch point synchronized. Due to backward compatible issue, we assume that in each cell, the adopted TDD DL UL configuration can only be selected from the seven TDD configuration patterns specified in LTE standards. Then in subframe 0, 1, 2, 5, there is only DL-DL or UL-UL interference, since these subframes have fixed link direction in any TDD configurations defined. For other subframes, their link direction depends on DL-UL configuration adopted, then there can be DL-UL interference depending on the TDD configuration adopted in neighboring cells. Then, as mentioned before, the subframes like 0, 1, 2 and 5 which have fixed link direction are called fixed subframe, while other subframes are called flexible subframe for simplicity. Due to different interference type in fixed subframe and flexible subframes, the SINR in fixed subframe and flexible subframe can be different.

DL-UL interference in flexible subframes will degrade the UL SINR significantly, while for DL flexible subframe, the interference there can be less than a fixed DL subframe. Then for data transmission in flexible subframe, if the link adaptation is still based on the same CQI report/SRS for fixed DL/UL subframes, it will not be accurate and then degrade the resource efficiency.

Currently in LTE R10, each UE can be configured zero or two CSI measurement subsets. That is to say, a UE can be configured to report a unified CQI or report separate CQIs for the configured two subframe subsets.

It is e.g. proposed in TS36.331 (which includes also the definitions of parameters mentioned below) in this regard that the corresponding configuration signaling is as follows:

CQI ReportConfig no

cqi ReportAperiodic MO iii ReportAperiodic

OPTIONAL Need ON

nom PDSCH II EPRE Offset INT EG I 1 §

However, the present inventors realized that although CSI reports for 2 subframe sets are possible, e.g. one for fixed subframe set, and another for flexible subframe set, how to generate the 2 CSI reports still needs to be studied. Currently, there are 2 methods for CQI measurement: one based on CRS measurement; another one based on CSI-RS measurement. And it is specified e.g. in TS 36.213 that "for a UE in transmission mode 9 when parameter pmi-RI-Report is configured by higher layers, the UE shall derive the channel measurements for computing the CQI value reported in uplink subframe n based on only the Channel-State Information (CSI) reference signals. For a UE in transmission mode 9 when the parameter pmi-RI-Report is not configured by higher layers or in other transmission modes, the UE shall derive the channel measurements for computing CQI based on CRS".

Since in Rel'11 legacy carrier, the CRS is available in each subframe, then it is possible to measure CQI for fixed subframe and flexible subframe separately. However, for UEs configured to measure CQI based on CSI-RS, there can be problems. Since for CSI-RS, it is periodically transmitted and the minimum period is 5ms, and according to current specifications, there is "zero or one configuration for which the UE shall assume non-zero transmission power for the CSI-RS", and non-zero CSI-RS is transmitted only in one subframe in each period, and the subframe is determined based on the offset indicated via higher layer signaling as shown in the table below. This means that once there is a non-zero CSI-RS configured in subframe 0, then it will always in subframe 0 with periodicity. In such case, the CSI-RS can only be used to measure the CQI for the fixed subframe, e.g. subframe 0, 1, 5 where there is always DL-DL interference.

As for CQI for flexible subframe, however, no CSI-RS is available for measurement, thus causing problems.

CSI reference signal subframe configuration

(Table 6.10.5.3-1 , from TS 36.211)

It should be noted that in Rel'11, New Carrier Type, NCT, the CRS is also configurable to be periodic, which means that the CRS is not available in some subframes. In such a case, UEs configured to measure CQI based on CRS has similar problem as mentioned above. While, although 2 subframe measurement subsets are supported and CQI report for 2 sets are enabled, however, as discussed in the above, how to derive the CQI for the 2 subsets still needs to be studied. And for UEs configured to conduct measurements based on CSI-RS/CRS, there is a problem since CSI-RS/CRS may not be available in both fixed and flexible subframes. In such a case, how UE should measure CQI should be specified and there should be a common understanding between eNB and UE. Hence, there is still a need to further improve such systems. Su m m arv

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

According to an aspect of the present invention (e.g. related to a terminal such as a user equipment, UE), there is provided

an apparatus as defined in claim 1 , and

an apparatus of functionality as defined in claim 26, and

a method as defined in claim 52.

According to an aspect of the present invention (e.g. related to a network transceiver device such as an evolved Node_B, eNB), there is provided an apparatus as defined in claim 18, and

an apparatus of functionality as defined in claim 43, and

a method as defined in claim 68.

Advantageous further developments are set out in respective dependent claims.

According to a further aspect of the present invention, as set out in claims 76 and 77, 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, 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, or any other suitable (hardware or software implemented) means for controlling), such as a terminal UE and its processor, or a network transceiver device eNB and its processor, cause the device to perform the respective method aspects. In particular, the above mentioned computer program product/products may be embodied as a computer-readable storage medium.

Accordingly, under at least some aspects of this invention, improvements are achieved in that, for example,

- solutions are provided to enable CQI measurement for 2 subframe sets;

- CSI (CQI) enhancement in the TDD DL-UL reconfiguration scenarios is provided which solves the problem caused by DL-UL interference;

- at least certain example embodiments enable to provide a CQI report for both fixed and flexible subframes;

- a CQI measurement problem is solved for flexible subframes, in case there is no CSI-RS, while a UE is required to measure CQI based on CSI- RS;

- enhancement in terms of CQI measurement is enabled for 2 CSI subframe sets;

- an associated signaling overhead is minimized. Some embodiments of the present invention can be applied to/embodied in relation to wireless communication systems and scenarios (e.g. in relation to LTE radio access or LTE-A radio access or other future 3GPP releases), in particular in modems and/or wireless devices and/or modules and/or chipsets thereof, in particular those related to/inserted in or insertable to devices such as terminals such as user equipments or "smartphones" or the like, as well as those related to/inserted in or insertable to network transceiver devices such as a Node B or evolved Node_B eNB.

Brief description of drawings For a more complete understanding of 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 of a network transceiver device eNB and a terminal UE and some signaling exchanged between, as well as an outline of their internal construction, according to at least some examples of aspects of the invention;

Fig. 2 illustrates a radioframe in terms of fixed subframes and flexible subframes;

Fig. 3 illustrates a radioframe in terms of control signaling present in plural subframe sets of a radioframe according to at least an example implementation of a first aspect of the invention;

Fig. 4 illustrates one example of the basic flowchart for a processing as carried out on a side of a terminal device such as a UE under at least an example implementation of the first aspect of the invention; Fig. 5 illustrates a radioframe in terms of control signaling present in plural subframe sets of a radioframe according to at least an example of implementation of a second aspect of the invention; Fig. 6 illustrates a schematic processing related to an example of implementation of the second aspect of the invention; and Fig. 7 illustrates one example of the basic flowchart for a processing as carried out on a side of a network transceiver device such as a eNB under at least an example implementation of the second aspect of the invention.

Description of example embodiments

Some exemplary aspects and/or embodiments of the invention will be described herein below.

Generally, the invention is implemented in a framework of e.g. a telecommunication system operating for example according to the LTE and/or LTE-A standard, or subsequent versions thereof, and more particularly, the at least individual aspects of the invention affect a terminal (user equipment UE) and/or a network transceiver device (evolved Node B) eNB operated within such a framework.

It is to be noted that as a mere example only, the description refers to such modules or devices or apparatuses related to user equipments, UEs, which conform to the LTE / LTE-A standard and are arranged / configured for communication with correspondingly configured network transceiver devices such as evolved NodeB's, eNBs, as the wireless communication modules or devices or apparatuses. Also, a network transceiver device may be represented by a access point AP.

However, this does not preclude the use of other wireless communication modules achieving similar functionalities, or the use of other communication standards such as LTE-A and beyond, as long as reference signals and correspondingly related signaling is applied/applicable. Also, the bandwidth of wireless communication is not crucial for the present invention.

General technical details of such 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 under one or more aspects of the present invention.

Fig. 1 illustrates one example of a network transceiver device such as an eNB and a terminal UE and some signaling exchanged between, as well as an outline of their internal construction.

Fig. 1 illustrates one example of a typical scenario to which some aspects of the invention are applicable and applied. As shown in Fig. 1, a network transceiver device such as a eNB, denoted by A, applies reference signal transmission for downlink transmission of (control) data to a terminal, e.g. a user equipment UE denoted by B. The (control) data carried in downlink comprise at least DL control channels (denoted by reference sign C1 ) such as the PDSCH and the PDCCH or the ePDCCH. At least the PDCCH/ePDCCH as one of the DL control channels carries also control information, e.g. known as downlink control information, DCI. Downlink Control Information is used to describe control signaling messages transmitted on the (enhanced) Physical Downlink Control Channel (PDCCH/ePDCCH), including for example downlink resource assignments (for the Physical Downlink Shared Channel (PDSCH)) and uplink transmission grants (for the Physical Uplink Shared Channel (PUSCH)). The terminal B feeds back feedback control signals in uplink, UL, to the eNB A. The uplink feedback comprises at least an uplink control channel (denoted by reference sign C2) such as the PUCCH. Data and/or signals carried on the PUCCH comprise, for example, at least CSI/CQI information and HARQ related information (ACKs/NACKs). The uplink feedback of the terminal UE B (such as a channel state indicator CSI and/or a channel quality indicator CQI) is at least partly derived based on evaluation of DMRS and/or other reference signals transmitted by the network transceiver device eNB A in downlink.

The eNB A comprises an apparatus 1, which in turn comprises at least a controller (or control module) 11 which is configured to control, among other parts of the eNB (not shown/discussed herein) a receiver/ transmitter (or transceiver module) 12 of the eNB, at least in terms of e.g. downlink signal transmission. The receiver/transmitter Rx/Tx 12, under control of the controller 11 , is caused to transmit in the PDSCH and/or PDCCH in DL to the terminal UE B. The receiver/transmitter Rx/Tx 12, under control of the controller 11 , is caused to receive the PUCCH in UL from the terminal UE B. As shown, the receiver/transmitter 12 is bi- directionally connected to the controller 11, which in turn is bi- directionally connected to a memory MEM 13. The memory stores various data, such as control code or the like used by the controller, data contained in feedback signals received in UL, data to be included in downlink control channels transmitted in DL, etc.

As further shown in Fig. 1, a terminal device such as a UE, denoted by B, is enabled to cope with signal transmission in downlink transmission of (control) data to a terminal, e.g. from a eNB denoted by A. The (control) data received in downlink comprise at least DL control channels such as the PDSCH and the PDCCH/ePDCCH. At least one of the DL control channels carries also control information, e.g. known as downlink control information, DCI. The terminal B causes to feed back feedback control signals in uplink, UL, to the eNB A. The uplink feedback comprises at least an uplink control channel such as the PUCCH. Data and/or signals carried on the PUCCH comprise, for example, at least CSI/CQI information and HARQ related information (ACKs/NACKs). The uplink feedback of the terminal UE B is at least partly derived based on evaluation of reference signals such as DMRS signals or other reference signals transmitted by the network transceiver device eNB A in downlink.

The UE B comprises an apparatus 2, which in turn comprises at least a controller (or control module) 21 which is configured to control, among other parts of the UE (not shown/discussed herein) a receiver/ transmitter (or transceiver module) 22 of the UE, at least in terms of reference signal reception and also configured to control related measurements and to cause adequate processing of the measurement results. The receiver/transmitter Rx/Tx 22, under control of the controller 21, is caused to receive the PDSCH and/or PDCCH/ePDCCH in DL from the eNB. The receiver/transmitter Rx/Tx 22, under control of the controller 21, is caused to transmit the PUCCH in UL to the eNB. As shown further, the receiver/transmitter 12 is bi-directionally connected to the controller 21, which in turn is bi-directionally connected to a memory MEM 23. The memory stores various data, such as control code or the like used by the controller, data caused to be included in feedback signals transmitted in UL, data included in downlink control channels received in DL, and/or other data, e.g. configuration data, measurement data obtained by a measurement module ((not shown), which could be associated to e.g. the control module 21 or the Rx/Tx module 22, (or be regarded as a separate module of the UE B)).

While herein before a focus was laid on aspects of the structural composition of entities to which some aspects of the present invention are applicable, herein below functional aspects will be explained. As derivable form the following, various functional behaviors and/or details of at least some examples of aspects of the invention will be described herein below. Under a first example aspect of the invention, a focus is laid on certain UE behaviors in relation to CQI measurement.

Namely, a terminal such as a UE is considered as comprising an apparatus, wherein that apparatus (e.g. a module or chipset or application specific integrated circuit, ASIC) comprises a controller. The controller is configured to cause reception (at a receiver) of data in a radio frame. Such radio frame comprises at least a first and a second subframe set, wherein the data comprise reference signals of at least two reference signal types. The controller further is configured to cause verification of the presence of a first reference signal type per subframe set, and responsive to a failure of the verification, for the subframe set concerned, causes measurement of a reference signal of a second reference signal type in said subframe set in which the first reference signal type is not verified to be present. The controller is further configured to process the measurement to derive a quality indication (CQI) for the data received.

That is, for a UE which is configured to measure CQI based on CSI-RS, and at the same time is configured 2 CSI subframe sets, in case CSI-RS is not available in at least one CSI subframe set, the UE will measure CQI in that CSI subframe set based on CRS or DMRS in configured ePDCCH resource (common search space or/and UE-specific search space).

Whether to measure CRS or DMRS of a downlink control channel resource such as the ePDCCH can be predefined. Alternatively, it can be derived implicitly, e.g. in case (distributed) ePDCCH is configured in that CSI subframe set and/or there is no CRS in that CSI subframe set, measurement of CQI is based on (distributed) ePDCCH DMRS, otherwise measurement is based on CRS. Alternatively, it is implicitly determined based on subframe type which reference signal of second reference signal type is to be used for measurement, e.g. for flexible subframe, always measure DMRS of ePDCCH.

Further alternatively, whether to measure CRS or DMRS of ePDCCH can be configured via higher layer signaling, e.g. when the terminal UE is configured for 2 CSI subframe sets and also configured to measure CQI based on CSI-RS, the network transceiver device eNB sends "signaling pmi-RI- Report" for the 2 sets separately. Then, if CSI-RS (as a first reference signal type) is not available in the subframe set concerned, the UE decides the behavior based on the pmi-RI-report for the corresponding set, e.g. if parameter "pmi Rl report" is set, measurement of CQI is based on ePDCCH DMRS; otherwise, measurement of CQI is based on CRS for the subframe set concerned. Note that transmission of CRS is not restricted to the ePDCCH region, but that CRS may equally be transmitted in the PDCCH or other downlink channel.

Thus, as set out herein before, a reference signal of a first reference signal type is e.g. a channel state indicator reference signal, CSI-RS, while a reference signal of a second reference signal type is e.g. one of a common reference signal, CRS, or a demodulation reference signal, DMRS.

One reference signal of a second reference signal type is conveyed in a downlink control channel resource, e.g. exemplified by a resource of an enhanced downlink control channel, ePDCCH. More specifically, according to at least an implementation example, the reference signal of the second reference signal type is conveyed in a common search space or a terminal specific search space within said downlink control channel resource or said enhanced downlink control channel resource. The controller is further configured to cause selection of a reference signal of a second reference signal type for measurement, wherein the selection is based on a predefined criterion, giving preference to one of reference signals of the second reference signal type. Alternatively, the selection is based on a derived criterion wherein the derived criterion causes selection of that reference signal of the second reference signal type for measurement, which is detected to be present in the subframe set concerned. Alternatively, the derived criterion causes selection of a reference signal of the second reference signal type for measurement, dependent on a property of the downlink control channel resource. Further, the derived criterion causes selection of a reference signal of the second reference signal type for measurement dependent on a subframe type of subframes constituting a subframe set.

Also, according to an example implementation, the selection is based on a criterion received from another entity, in that the controller is further configured to cause reception of a respective reporting indication from another entity, wherein a respective reporting indication is applied as criterion to one of the subframe sets. Namely, if the reporting indication is set to a specific value for the subframe set for which verification of the presence of a first reference signal type failed, a specific reference signal of a second reference signal type for measurement is selected, whereas if not set, another one thereof is selected. According to some of the above aspects, the apparatus comprises a terminal device, e.g. a UE, or part of a terminal device, e.g. a modem, and wherein the apparatus conforms to operate according to the LTE™ or LTE-A™ standards, as e.g. illustrated in Fig. 1 as UE denoted by numeral B. Fig. 3 illustrates a radioframe in terms of control signaling present in plural subframe sets of a radioframe according to at least an example implementation of the above explained first aspect of the invention;

It is assumed for the example explained that one UE is configured to use transmission mode 9 in DL, and CSI-RS configuration for this UE is in subframe 0 as shown in Figure 3, and at the same time the following is configured for CQI report: pm i RI Report is configured; two subframe sets c_CSI0 = subframes (0,1,5,6) (illustrated in black) and c_CSI1 = (4,9)

(illustrated in hatching) are configured.

The reference signal of first type, CSI-RS, is present only in one of the subframe sets, i.e. in c_CSI0- As shown, (dashed vertical line) it is present in subframe zero only. DL subframes not allocated to one of the two subframe sets could be allocated to a third subframe set, or could be allocated to one of the two subframe sets in another subframe set configuration. In such case, according to TS 36.213, the UE is required to measure CQI based on CSI-RS. However, there is no CSI-RS available in subframe 4 or 9. Then, in such a case, according to the above first aspect, the UE will measure CQI for subframe set c_CSI1based on CRS or DMRS. In one example embodiment, UE will measure CRS or DMRS in such case based on predefinition; for example, it can be predefined if there has no CSI-RS when UE is required to measure CQI based on CSI-RS, UE will measure CRS. Or it can be predefined that in such case, UE measure DMRS in flexible subframe.

In another example embodiment, UE will measure CRS or DMRS based on whether distributed ePDCCH is configured in subframe set c_CSI1 , i.e, subframe 4 or 9. If distributed ePDCCH is configured, the UE measures CQI based on DMRS in distributed ePDCCH, otherwise it measures CQI based on CRS.

In another example embodiment, UE will measure CRS or DMRS based on whether CRS is available in subframe set c_CSI1, i.e. in subframe 4 or 9 . If

CRS is available, UE measures CQI based on CRS, otherwise it measures CQI based on DMRS in ePDCCH.

Further, in another example embodiment, the eNB will configure pmi RI Report separately for the 2 CSI subframe sets and the UE will correspodnigly receive those settings and apply them at the UE side. For example, assume that "pmi_RI_Report" is setup for C_csl0 but not setup for c_CSI1 , then the UE will measure CQI based on CSI-RS for subframe set _cs/0, while it measures CQI based on CRS for subframe set _CSI1. Fig. 4 illustrates one example of the basic flowchart for a processing as carried out on a side of a terminal device such as a UE, e.g. a controller or means for controlling thereof, under at least an example implementation of the first aspect of the invention. The flowchart insofar represents a method carried out by the terminal device based on the functionality imparted to the apparatus.

The process starts in a stage S40. In a stage S41, the controller, causes to receive data in a radio frame comprising at least a first and a second subframe set, wherein the data comprise reference signals of at least two reference signal types. In a stage S42, the controller causes to verify the presence of a first reference signal type per subframe set. Responsive to a failure of the verification, for the subframe set concerned, in a stage S43, the controller causes to measure a reference signal of a second reference signal type in said subframe set in which the first reference signal type is not verified to be present. Else, i.e. if verification did not fail, the reference signal of the first type is measured. In any case, i.e. independent of which type of reference signal was used for measurement, the controller is further processes the measurement to derive a quality indication (CQI) for the data received, stage S44. The process/flow then ends in stage S45, i.e. other processing not particularly related to this aspect of the invention is nevertheless continued.

Other details are of course as the same for the method as outlined before with regard to the apparatus, e.g. in terms of the reference signal types and the selection of one of reference signals of the second type. A repeated description here is thus considered dispensable.

Under a second example aspect of the invention, a focus is laid on certain eNB behaviors in relation to enable CQI measurement by a UE. Namely, a network transceiver device such as a eNB or AP is considered as comprising an apparatus, wherein that apparatus (e.g. a module or chipset or application specific integrated circuit, ASIC) comprises a controller. The controller is configured to cause transmission of data in a radio frame comprising at least a first and a second subframe set, wherein the data comprise reference signals of at least two reference signal types The controller is further configured to cause to configure transmission of data in terms of a periodic presence of the first reference signal type in each subframe set and cause to transmit corresponding configuration data to another entity, e.g. the terminal UE.

In this regard, distinct configuration data are caused to be transmitted to be applied per subframe set. Or, single configuration data are caused to be transmitted, useable to derive respective distinct configurations to be applied per subframe set, by applying a rule thereto.

As above, a reference signal of a first reference signal type is a channel state indicator reference signal, CSI-RS, and a reference signal of a second reference signal type is one of a common reference signal, CRS, or a demodulation reference signal, DMRS in configured ePDCCH resource. A reference signal of a second reference signal type is transmitted in a downlink control channel resource, e.g. an ePDCCH. The reference signal of the second reference signal type is transmitted in a common search space or a terminal specific search space within said downlink control channel resource.

In some embodiments of the above aspect of the invention, the apparatus comprises a network transceiver device, e.g. a eNB or access point AP, or in some embodiments of the invention, the apparatus comprises part of the network transceiver device, e.g. a modem, and wherein the apparatus conforms to operate according to the LTE™ or LTE-A™ standards, as e.g. illustrated in Fig. 1 as eNB denoted by numeral A.

Namely, as set out above, for a UE which is configured to measure CQI based on CSI-RS, and at the same time is configured 2 CSI subframe sets, then the eNBs are configured to apply non-zero CSI-RS for the 2 sets separately. One alternative is to use 2 (distinct) CSI-RS configuration signalings (sent to the UEs). Another alternative is to predefine an implicit rule, thus enabling a receiving UE to derive the distinct CSI-RS configurations for both subframe sets based on a single CSI-RS configuration signaling. Fig. 5 illustrates a radioframe in terms of control signaling present in plural subframe sets of a radioframe according to at least an example of implementation of a second aspect of the invention.

It is assumed for the example explained that one UE is configured to use transmission mode 9 in DL, and at the same time, pm i RI Report is configured and two subframe sets c_CSI0 = subframes (0,5) and ^ccsi_,i= (3,4,8,9) are configured. In such case, according to at least an example of the second aspect of the invention, the eNB configures non-zero CSI-RS for the two subframe sets

C_CSI0 and c_cs separately. For example, I_csl__RS.set0 =5 for C_CSI0 and I_CSI __RS__setl = 19 for c_CSI1. Then there will be CSI-RS in subframe 0 with period of 10ms, and also CSI-RS in subframe 4 with period of 20ms as shown in Figure 5. In such case, the CQI measurement for both CSI subframe sets is enabled to be based on CSI-RS as a reference signal of a first type. Namely, as shown, the eNB applies a configuration (and optionally informs the UE about this) such that CSI-RS is present in a first subframe set, as shown by a dashed vertical line, as well as in a second subframe set, as shown by a solid vertical line, with respective different periodicity in the illustrated example scenario.

Fig. 6 illustrates a schematic processing related to an example of implementation of the second aspect of the invention.

In another embodiment, the eNB can configure only one /_CSi _RS > but let the UEs to derive the CSI-RS configuration for the two CSI subframe sets implicitly as shown in Figure 6.

For example, the eNB configures /_CSi _Rs =5 and then based on Table 6.10.5.3-1 from TS 36.211 (cf. page 9 above), r_CSI._RS = 10 and A_csi._rs = 0, now there can be for example a predefined rule as follows:

Example Rule:

TcSI-RS-setO — 2 X r_csI__RS

TcSI-RS-setl — 2 X r_csI__RS

Δ CSI-RS-setO ^' CSI-RS and ^CSI-RS-setl— ^CSI-RS + ^CSI-RS Then based on this rule, the CSI-RS configuration for the 2 CSI subframe sets can be derived to be:

CSI-RS with period 20ms in subframe 0 for c_CSI0 and CSI-RS with period of 20ms in subframe 10 for c_CSI1.

Another example of a predefined rule can be as follows:

^CSI-RS-setO ⁼ AcSI-RS ^anCl

Acsi-Rs-sea = 1 ^st su bf ram e i n c_cs ;

Then with this rule, the CSI-RS configuration for the 2 CSI subframe sets can be derived to be: CSI-RS with period 10ms in subframe 0 for c_CSI0 and CSI-RS with period of 1 ms in subframe 4 for c_CSI1.

Fig. 7 illustrates one example of the basic flowchart for a processing as carried out on a side of a network transceiver device such as a eNB, e.g. a controller or means for controlling thereof, under at least an example implementation of the second aspect of the invention. The flowchart insofar represents a method carried out by the network transceiver device based on the functionality imparted to the apparatus.

The process starts in a stage S70. In a stage S71, the controller, causes to transmit data in a radio frame comprising at least a first and a second subframe set, wherein the data comprise reference signals of at least two reference signal types. As shown in a stage S72, the controller further causes configuring transmission of data in terms of a periodic presence of the first reference signal type in each subframe set, and further causes transmitting of corresponding configuration data to another entity in a stage S73. The process/flow then ends in stage S74, i.e. other processing not particularly related to this aspect of the invention is nevertheless continued.

Other details are of course as the same for the method as outlined before with regard to the apparatus, e.g. in terms of the reference signal types and the distinct configuration data that are caused to be transmitted to be applied per subframe set and/or which are useable at a receiving side to derive, by applying one or more rules thereto, the configuration of the subframe sets in terms of reference signals used therein as applied by the network transceiver device, such as an eNB. A repeated description here is thus considered dispensable.

It should be noted that though hereinbefore a focus was laid on solving the problem of CQI measurement in case of CSI-RS is not available in at least one CSI subframe set, the proposed solutions can also be extended to solve the problem where UE is configured to measure CQI based on CRS, but CRS is not available in at least one CSI subframe set.

Further, although the first and second aspects have been described herein above as being rather independent from each other, they may interact with each other. For example, assume a network transceiver device eNB transmitting data in radio frames comprising at least a first and a second subframe set, wherein the data comprise reference signals of at least two reference signal types. Assume a terminal UE receiving those and configured to operate as outlined in relation to the first aspect. I.e. the terminal UE and/or an apparatus thereof and its controller, cause verification of the presence of a first reference signal type per subframe set, and responsive to a failure of the verification, for the subframe set concerned, cause measurement of a reference signal of a second reference signal type in said subframe set in which the first reference signal type is not verified to be present. The measurement and a resulting channel quality indication CQI is then sent in uplink to the eNB. The eNB, is e.g. triggered to use the second aspect when it is found that the accuracy of the received CQI is not satisfying, e.g, due to a configured ePDCCH resource being not wide enough. And it can also be triggered back so as to not apply the second aspect (and insofor rather apply the first aspect) when the ePDCCH is reconfigured with more physical resource blocks PRBs. Optionally other trigger conditions may additionally or alternatively be applied. That is, upon being triggered to apply the second aspect, the eNB configures transmission of data in terms of a periodic presence of the first reference signal type in each subframe set and causes to transmit corresponding configuration data to another entity, i.e. to the UE. The UE may then be triggered by e.g. receipt of such configuration data (or by applying a rule to derive the configuration data) to suspend its operation insofar as it is related to the first aspect of the invention. Other trigger conditions, e.g. as outlined in example above, may lead to the eNB and UE switching back to the initial settings, i.e. UE operating in line with the first aspect of the invention and the eNB not applying the second aspect of the invention. It is still to be noted that some embodiments of the invention may be implemented in software, hardware, application logic or a combination thereof, i.e. 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 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 at least some acronyms:

CA Carrier Aggregation

CATT Chinese Academy for Technology and Telecommunications

CC Component Carrier

CRS Common Reference Signal / Cell-specific reference signal

CSI Channel State I nformation

CSI-RS CSI Reference Signal

CQI Channel Quality Indicator

DL Downlink

elMTA enhancements to Interference Management and Traffic

Adaptation

eNB Enhanced Node B

HARQ Hybrid Automatic Repeat reQuest

LA Local Area

LTE Long Term Evolution

MAC Medium Access Control

NCT New Carrier Type

PHY PHYsical layer

ePDCCH enhanced PDCCH

PDCCH Physical Downlink Control CHannel PUCCH Physical Uplink Control CHannel

PUSCH Physical Uplink Shared CHannel

RA Random Access

Rl Rank 1 ndication

RLM Radio Link Management

RNTI Radio Network Temporary Identifier

RRC Radio Resource Control

RRM Radio Resource Management

SI System Information

SINR Signal to Interference plus Noise Ratio

SPS Semi-Persistent Scheduling

SRS Sounding Reference Signal

TDD Time Division Duplex

TPC Transmit Power Control

UL Uplink

UE User Equipment

Wl Working Item

Accordingly, as has been described herein above, in terms of enhancements in evaluating channel quality, an example aspect of the present invention encompases an apparatus, comprising a controller, configured to cause reception of data in a radio frame comprising at least a first and a second subframe set, wherein the data comprise reference signals of at least two reference signal types, cause verification of the presence of a first reference signal type per subframe set, and responsive to a failure of the verification, for the subframe set concerned, cause measurement of a reference signal of a second reference signal type in said subframe set in which the first reference signal type is not verified to be present. Another example aspect encompasses an apparatus, comprising a controller, configured to cause transmission of data in a radio frame comprising at least a first and a second subframe set, wherein the data comprise reference signals of at least two reference signal types, wherein the controller is further configured to cause to configure transmission of data in terms of a periodic presence of the first reference signal type in each subframe set and cause to transmit corresponding configuration data to another entity. Further, respective methods and computer program products are addressed.

Claims

WHAT I S CLAI MED I S:

1. An apparatus, comprising:

a controller, configured to

cause reception of data in a radio frame comprising at least a first and a second subframe set, wherein the data comprise reference signals of at least two reference signal types,

cause verification of the presence of a first reference signal type per subframe set, and

responsive to a failure of the verification, for the subframe set concerned,

cause measurement of a reference signal of a second reference signal type in said subframe set in which the first reference signal type is not verified to be present.

2. An apparatus according to claim 1, wherein the controller is further configured to process the measurement to derive a quality indication (CQI) for the data received.

3. An apparatus according to claim 1, wherein

a reference signal of a first reference signal type is a channel state indicator reference signal, CSI-RS.

4. An apparatus according to claim 1, wherein

a reference signal of a second reference signal type is one of a common reference signal, CRS, or a demodulation reference signal, DMRS.

5. An apparatus according to claim 1 or 4, wherein

a reference signal of a second reference signal type is conveyed in a downlink control channel resource or an enhanced downlink control channel , ePDCCH, resource.

6. An apparatus according to claim 5, wherein

the reference signal of the second reference signal type is conveyed in a common search space or a terminal specific search space within said downlink control channel resource or said enhanced downlink control channel, ePDCCH, resource.

7. An apparatus according to any of claims 4 to 6, wherein

the controller is further configured to

cause selection of a reference signal of a second reference signal type for measurement.

8. An apparatus according to claim 7, wherein

the selection is based on a predefined criterion, giving preference to one of reference signals of the second reference signal type.

9. An apparatus according to claim 7, wherein

the selection is based on a derived criterion.

10. An apparatus according to claim 9, wherein

the derived criterion causes selection of that reference signal of the second reference signal type for measurement, which is detected to be present in the subframe set concerned.

11. An apparatus according to claim 9, wherein

the derived criterion causes selection of a reference signal of the second reference signal type for measurement, dependent on a property of the downlink control channel resource.

12. An apparatus according to claim 9, wherein the derived criterion causes selection of a reference signal of the second reference signal type for measurement dependent on a subframe type of subframes constituting a subframe set.

13. An apparatus according to claim 7, wherein

the selection is based on a criterion received from another entity.

14. An apparatus according to claim 13, wherein the controller is further configured to

cause reception of a respective reporting indication from another entity, wherein a respective reporting indication is applied as criterion to one of the subframe sets.

15. An apparatus according to claim 14, wherein,

if the reporting indication is set to a specific value for the subframe set for which verification of the presence of a first reference signal type failed, a specific reference signal of a second reference signal type for measurement is selected, whereas if not set, another one thereof is selected.

16. An apparatus according to any of claims 1 to 15, wherein

the apparatus comprises a user equipment.

17. An apparatus according to any of claims 1 to 16, wherein

the apparatus conforms to operate according to the LTE™ or LTE-A™ standards.

18. An apparatus, comprising:

a controller, configured to

cause transmission of data in a radio frame comprising at least a first and a second subframe set, wherein the data comprise reference signals of at least two reference signal types, wherein the controller is further configured to

cause to configure transmission of data in terms of a periodic presence of the first reference signal type in each subframe set and cause to transmit corresponding configuration data to another entity.

19. An apparatus according to claim 18, wherein

distinct configuration data are caused to be transmitted to be applied per subframe set.

20. An apparatus according to claim 18, wherein

single configuration data are caused to be transmitted, useable to derive respective distinct configurations to be applied per subframe set, by applying a rule thereto.

21. An apparatus according to claim 18, wherein

a reference signal of a first reference signal type is a channel state indicator reference signal, CSI-RS, and a reference signal of a second reference signal type is one of a common reference signal, CRS, or a demodulation reference signal, DMRS.

22. An apparatus according to claim 18 or 21 , wherein

a reference signal of a second reference signal type is transmitted in a downlink control channel resource or an enhanced downlink control channel , ePDCCH, resource.

23. An apparatus according to claim 22, wherein

the reference signal of the second reference signal type is transmitted in a common search space or a terminal specific search space within said downlink control channel resource or said enhanced downlink control channel , ePDCCH, resource.

24. An apparatus according to any of claims 18 to 23, wherein the apparatus comprises a network transceiver device.

25. An apparatus according to any of claims 18 to 24, wherein

26. An apparatus, comprising:

a means for controlling, configured to

responsive to a failure of the verification, for the subframe set concerned,

27. An apparatus according to claim 26, wherein the means for controlling is further configured to process the measurement to derive a quality indication (CQI) for the data received.

28. An apparatus according to claim 26, wherein

29. An apparatus according to claim 26, wherein

30. An apparatus according to claim 26 or 29, wherein a reference signal of a second reference signal type is conveyed in a downlink control channel resource or an enhanced downlink control channel , ePDCCH, resource.

31. An apparatus according to claim 30, wherein

the reference signal of the second reference signal type is conveyed in a common search space or a terminal specific search space within said downlink control channel resource or said enhanced downlink control channel , ePDCCH, resource.

32. An apparatus according to any of claims 29 to 31 , wherein

the means for controlling is further configured to

33. An apparatus according to claim 32, wherein

34. An apparatus according to claim 32, wherein

the selection is based on a derived criterion.

35. An apparatus according to claim 34, wherein

36. An apparatus according to claim 34, wherein

37. An apparatus according to claim 34, wherein

the derived criterion causes selection of a reference signal of the second reference signal type for measurement dependent on a subframe type of subframes constituting a subframe set.

38. An apparatus according to claim 32, wherein

the selection is based on a criterion received from another entity.

39. An apparatus according to claim 38, wherein the means for controlling is further configured to

40. An apparatus according to claim 39, wherein,

41. An apparatus according to any of claims 26 to 40, wherein

the apparatus comprises a user equipment.

42. An apparatus according to any of claims 26 to 41 , wherein

43. An apparatus, comprising:

a means for controlling, configured to cause transmission of data in a radio frame comprising at least a first and a second subframe set, wherein the data comprise reference signals of at least two reference signal types, wherein

the means for controlling is further configured to

44. An apparatus according to claim 43, wherein

45. An apparatus according to claim 43, wherein

46. An apparatus according to claim 43, wherein

47. An apparatus according to claim 43 or 46, wherein

48. An apparatus according to claim 47, wherein

49. An apparatus according to any of claims 43 to 48, wherein

the apparatus comprises a network transceiver device.

50. An apparatus according to any of claims 43 to 49, wherein

51. A method, comprising:

receiving of data in a radio frame comprising at least a first and a second subframe set, wherein the data comprise reference signals of at least two reference signal types,

verifying the presence of a first reference signal type per subframe set, and

responsive to a failure of the verification, for the subframe set concerned,

measuring a reference signal of a second reference signal type in said subframe set in which the first reference signal type is not verified to be present.

52. A method according to claim 51, further comprising

processing the measurement to derive a quality indication (CQI) for the data received.

53. A method according to claim 51, wherein

54. A method according to claim 51, wherein a reference signal of a second reference signal type is one of a common reference signal, CRS, or a demodulation reference signal, DMRS.

55. A method according to claim 51 or 54, wherein

56. A method according to claim 55, wherein

57. A method according to any of claims 54 to 56, further comprising

selecting a reference signal of a second reference signal type for measurement.

58. A method according to claim 57, wherein

59. A method according to claim 57, wherein

the selection is based on a derived criterion.

60. A method according to claim 59, wherein

61. A method according to claim 59, wherein the derived criterion causes selection of a reference signal of the second reference signal type for measurement, dependent on a property of the downlink control channel resource.

62. A method according to claim 59, wherein

63. A method according to claim 57, wherein

the selection is based on a criterion received from another entity.

64. A method according to claim 63, further comprising

receiving a respective reporting indication from another entity, wherein a respective reporting indication is applied as criterion to one of the subframe sets.

65. A method according to claim 64, wherein,

66. A method according to any of claims 51 to 65, wherein

the method is carried out in a user equipment.

67. A method according to any of claims 51 to 66, wherein

the method conforms to the LTE™ or LTE-A™ standards.

68. A method, comprising: transmitting data in a radio frame comprising at least a first and a second subframe set, wherein the data comprise reference signals of at least two reference signal types, wherein

configuring transmission of data in terms of a periodic presence of the first reference signal type in each subframe set and transmitting corresponding configuration data to another entity.

69. A method according to claim 68, wherein

70. A method according to claim 68, wherein

71. A method according to claim 68, wherein

72. A method according to claim 68 or 71, wherein

73. A method according to claim 72, wherein

74. A method according to any of claims 68 to 73, wherein

the method is carried out in a network transceiver device.

75. A method according to any of claims 68 to 74, wherein

the method conforms to the LTE™ or LTE-A™ standards.

76. A computer program product comprising respective computer- executable components which, when the program is run on a computer, are configured to perform the above method aspects according to any of claims 51 to 67.

77. A computer program product comprising respective computer- executable components which, when the program is run on a computer, are configured to perform the above method aspects according to any of claims 68 to 75.