WO2016089268A1

WO2016089268A1 - Reduced channel state information reporting in a multi-carrier wireless communication system

Info

Publication number: WO2016089268A1
Application number: PCT/SE2014/051461
Authority: WO
Inventors: Sairamesh Nammi
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2014-12-05
Filing date: 2014-12-05
Publication date: 2016-06-09
Anticipated expiration: 2017-06-05

Abstract

Method for operating a wireless device, the wireless device being connected to a first-and a second cell with HSDPA operation, the wireless device being further configured with a first-and a second CQI reporting period associated with the respective first-and second cell, wherein the method comprises determining, based on the first-and the second CQI reporting periods, whether to send composite CQI feedback or non-composite CQI feedback and based on the determining sending CQI feedback accordingly.

Description

REDUCED CHANNEL STATE INFORMATION REPORTING IN A MULTI- CARRIER WIRELESS COMMUNICATION SYSTEM

Technical field

The present disclosure relates generally to a network node and a wireless device of a radio network and methods therein, for flexible channel quality indicator (CQI) reporting in a wireless communication system with HSDPA operation.

Background

In uplink HSPA all wireless devices are transmitting using same spreading codes and wireless devices are separated by non-orthogonal scrambling codes. This results in that wireless devices in uplink HSPA transmissions need to share an interference limited resource. Reducing the interference in uplink frequencies is thereby critical to ensure high SIR (Signal-to-lnterference Ratio) levels on uplink transmission channel and to maintain a stable system operation.

The HS-DPCCH transmissions from all UEs contribute to the interference level and the Rise over Thermal (RoT) in uplink. However, there are scenarios where the HS-DPCCH transmissions could be reduced for lowering the RoT and enabling higher system throughput capacity or increasing coverage.

Configuring the reporting period of HS-DPCCH is a tricky problem. If the reporting period is small, the accuracy of the CQI is good, i.e. the base station has updated information of the radio channel conditions. The drawback is that it requires more signaling from UE. This can cause a reduced system throughput for uplink, i.e. uplink capacity.

On the other hand, if the reporting period is large, the accuracy of the CQI will be worse and the downlink throughput may be reduced for some channels. In WO 2014/148964 A1 , a technique to reduce channel state information is described.

The solutions covered in WO 2014/148964 A1 assume that the UE is configured with only one carrier downlink transmission from a single cell. But when the UE is configured with multiple carriers (i.e. a UE can simultaneously send and/or receive data from two cells on different carriers), the configuration of reporting period is even more complex since there is only one HS-DPCCH feedback channel.

If the reporting period is very small, the quality of the CQI is very good, i.e., the base station is keep tracking of the channel. The drawback is that it may require high signaling overhead from UE or wireless device. This can cause a reduced system throughput for uplink, i.e. uplink capacity.

On the other hand if the reporting period is statically set to a high value, the downlink throughput may be reduced for some channels since the scheduling may be based on outdated CQI.

In some scenarios, it may be beneficial to switch off the reporting when there is no downlink data to schedule. This scenario is described in WO 2014/148964 A1 .

However, the solutions covered in WO 2014/148964 A1 assume that the wireless device is configured in a mode where downlink transmission is done from a single Node B. However, when the wireless device is configured in a multipoint wireless communication system (wireless device can simultaneously receive data from two Node Bs and/or cells), the 3GPP standard recommends using a single HS- DPCCH. In these cases, the configuration of reporting period is more complex because if we switch off the CQI reporting period of one Node B, it might impact (decrease in throughput) the performance on the other Node B.

Summary

It is an objective of the aspects described herein, to provide a flexible approach on how to report CQI feedback.

In particular, in connection with HSDPA operation of a wireless device connected to several cells in a wireless communication system, it may not be beneficial to report CQI feedback for a cell in which there is no data activity. Instead, if there is no activity in one of the cells, the wireless device can adaptively exclude the CQI reporting for such a cell and consequently focus on reporting CQI only for a cell in which there is activity and thereby reduce the signaling overhead of HS-DPCCH. The reduced signaling in UL will decrease the UL interference. When interference is reduced it may be possible to add more traffic with maintained SINR.

Some of the disclosed solutions described herein will enable an improvement of the CQI detection capability in the NodeB or network node. The objective described above, is achieved by the methods, devices and arrangements described herein.

According to one aspect, a method for operating a wireless device, the wireless device being connected to a first- and a second cell with HSDPA operation, the wireless device being further configured with a first- and a second CQI reporting period associated with the respective first- and second cell, wherein the method comprises determining (S1 ), based on the first- and the second CQI reporting periods, whether to send composite CQI feedback or non-composite CQI feedback and sending (S2) CQI feedback according to said determination.

According to a second aspect, there is disclosed a wireless device connectable to a first- and a second cell with HSDPA operation, the wireless device is further adapted to being configured with a first- and a second CQI reporting period associated with the respective first- and second cell, the wireless device being additionally adapted to determine, based on the first- and the second CQI reporting periods, whether to send composite CQI feedback or non-composite CQI feedback and send CQI feedback according to said determination.

According to a third aspect, further disclosed is a method for operating a network node of a wireless communication network, the network node is controlling at least a first cell, wherein the first cell is connected to a wireless device in HSDPA operation with the cell, wherein the HSDPA operation is in connection with at least a second cell, wherein the method comprises receiving CQI feedback,

determining, based on composition conditions, whether the CQI feedback is composite or non-composite CQI feedback

According to a fourth aspect, it is disclosed, a network node adapted to operate in a wireless communication network; the network node being adaptable to control at least a first cell, wherein the first cell is connected to a wireless device in HSDPA operation wherein the HSDPA operation is connected with at least a second cell wherein the network node being further adaptable to receive CQI feedback and determine, based on composition conditions, whether the CQI feedback is composite or non-composite CQI feedback.

According to a fifth aspect, there is disclosed a first computer program comprising instructions which, when executed on a processing circuitry, cause the processing circuitry to carry out and/or control any methods, performed in or by the wireless device, disclosed herein. According to a sixth aspect, there is disclosed a second computer program comprising instructions which, when executed on a processing circuitry, cause the processing circuitry to carry out and/or control any methods, performed in or by the network node, disclosed herein.

According to a seventh aspect, there is disclosed a carrier containing the first computer program, wherein the carrier is one of an electronic signal, optical signal, radio signal, computer or processing circuitry readable storage medium.

According to an eighth aspect, there is disclosed a carrier containing the second computer program, wherein the carrier is one of an electronic signal, optical signal, radio signal, computer or processing circuitry readable storage medium. The above network node, wireless device and methods therein may be

implemented and configured according to different optional embodiments to accomplish further features and benefits, to be described below. Brief description of drawings

The solution will now be described in more detail by means of exemplary embodiments and with reference to the accompanying drawings, in which:

Fig. 1 Schematic illustration of an example of a wireless communication system (100) serving a wireless device (200) in HSDPA operation.

Fig. 2a Illustrates a message sequence chart for data transmission with one cell involved in HSDPA operation in a wireless communication system.

Fig. 2b Illustrates a message sequence chart for data transmission with two cells involved in HSDPA operation in a wireless communication system. Fig. 3a Illustration of an example of the HS-DPCCH structure for non- composite CQI feedback for HSDPA operation in a wireless communication system.

Fig. 3b Illustration of an example of the HS-DPCCH structure for composite CQI feedback for HSDPA operation in a wireless communication system. Fig 4 Illustration of an example of the HS-DPCCH structure for composite

CSI feedback.

Fig. 5a An example of how the CQI can be concatenated prior to encode composite CQI feedback.

Fig. 5b An example the how the CQI may be concatenated with non-existing CQI from a serving cell in which the wireless device has detected low activity.

Fig. 5c An example the how the CQI may be concatenated with non-existing CQI from a non-serving cell in which the wireless device has detected low activity

Fig. 6 Illustration different CQI reporting periods related to inactivity on HS- PDSCH. Fig. 7 Illustration of the timing between the uplink channels and the downlink channels in HSDPA operation.

Fig. 8 Another illustration of how the CQI reporting periods for the different cells influence the CQI reporting time instances on the HS-DPCCH in HSDPA operation

Fig. 9 A method in a wireless device. Fig. 10 A method in a network node. Fig. 1 1/13 An example of a wireless device.

Fig. 12/14 An example of a network node.

Detailed description

In the following, different aspects will be described in more detail with references to certain embodiments and to accompanying drawings. For purposes of explanation and not limitation, specific details are set forth, such as particular scenarios and techniques, in order to provide a thorough understanding of the different embodiments. However, other embodiments that depart from these specific details may also exist.

In the context of this disclosure some basic concepts are defined

A wireless device may be connected and/or connectable to one or more cells. This may mean that the wireless device may send- and/or transmit- as well as receive data to and/or from the cell and/or network node. A wireless device may be connected to one or more cells with HSDPA operation. This may be regarded as if the wireless device may send- and/or transmit- as well as receive data to and/or from at least two cells and/or network nodes simultaneously on the same frequency carrier.

In HSDPA operation a wireiess device can be connected to more than one cell. capabilities, be configured to operate, simultaneously, in multiple radio frequencies ao.c|/o„r.carriers,v In the context of this disclosure, a wireless device may be connected to a first- and a second cell with HSDPA operation, In this case a first cell may be defined as the serving HS-DSCH cell, The serving HS-DSCH cell is associated with the UTRAN access point and/or NodeB and/or network node, and may perform transmission and reception of the serving HS-DSCH radio link for a given wireless device. The serving HS-DSCH cell may be part of the current active set of the wireless device.

In this context, a second cell may be defined as an assisting secondary serving HS-DSCH Cell. The assisting secondary serving HS-DSCH Cell is a cell which in addition to the serving HS-DSCH cell, is operating on another frequency and/or within another carrier. The first- and the second cells may operate on different carriers and/or frequencies.

In muiti carrier HSDPA operation there may be a common channel and/or carrier for control Information. The common channel and/or carrier Is common for cells and/or HSDPA radio links In mu!ticanrier operation. Control Information in this context may e.g. be e.g. carrier specific channel state Information such as e.g. CQI and HARQ-ACK. In one example, the common control channel can be used for sending CQI feedback for each cell and/or HSDPA radio link In muiti carrier HSDPA operation. The common channel and/or carrier may be used for transmission of e.g.

composite and/or non-composite CQI feedback from a wireless device to a network node. The common channel and/or carrier may be e.g. an HS-DPCCH. It can be anticipated that the common channel is configured to operate In any of the cells and/or carriers in the HSDPA operation or In other cell. One specific form of muiti carrier operation may be carrier aggregation,

A CQI reporting period may be associated with one cell only. A CQI reporting period being associated with one cell may mean that the CQI reporting period is valid and/or relevant for reporting CQI feedback for that cell although the UE or wireless device, may be connected to more than one cell in HSDPA operation. A wireless device being connected to a cell in HSDPA operation can be defined as if the wireless device may receive user data and/or control data over an HS- PDSCH channel in a cell provided by a network node in a 3GPP WCDMA UTRAN. A wireless device being connected to a cell in HSDPA operation may be

connected to the cell via an HSDPA radio link. A wireless device may be

connected to more than one cell in HSDPA operation. In this case there may be more than one HSDPA radio links for the wireless device, in particular there may be one HSDPA radio link per cell. It may be possible to monitor and/or supervise an HSDPA radio link and feedback CQI values for the HSDPA radio link. CQI values may be a value between 0 and 31 that may represent the measured and/or estimated, SINR which the wireless device has experienced. The CQI value may be represented by five bits and the five bits may be encoded into 20 bits. These 20 bits may be transmitted in two slots in a HS-DPCCH subframe as CQI feedback. The subframe- and slot-structure of an HS-DPCCH channel is illustrated in figure 2. A CQI reporting time instance may be defined as position in a feedback channel. The feedback channel may be HS-DPCCH. The feedback channel may be defined per cell and/or per HSDPA radio link. In case of HSDPA operation the HS-DPCCH may be a common feedback channel for all cells in HSDPA operation with the wireless device. The position in the feedback channel may be expressed as a slot and/or slots in a subframe or TTI on feedback channel.

A wireless device may be said to being configured with a CQI reporting period, which may mean that the wireless device is informed by a network node and/or a cell provided by a network node, about a time interval. The time interval may be used to control the time between the starting point of two consecutive CQI reporting time instances associated with one cell. The CQI reporting period and/or the time interval may be expressed in terms of subframes and/or slots and/or TTI's of the feedback channel. A time interval and/or CQI reporting period is periodic in the sense that when the time interval and/or period has elapsed, a new period and/or time interval is started. If the wireless device is connected to several cells with HSDPA operation, a configuration of CQI reporting period may be done for each cell involved in the HSDPA operation.

CQI feedback may be composite- and/or non-composite CQI feedback. Composite CQI feedback may comprise a jointly encoded CQI feedback, wherein each CQI feedback value may be related to different cells and/or HSDPA radio links in e.g. HSDPA operation. Composite CQI feedback may be sent from the wireless device when a wireless device has determined that the CQI reporting time instance for a first cell coincide with a CQI reporting time instance for a second HSDPA radio link.

In figure 8 there is illustrated an example of composite CQI feedback. Based on the cell specific parameters the wireless device may determine that composite CQI feedback (CQI_C) may be sent in HS-DPCCH subframe 1 and subframe 5. The wireless device may also determine, based on cell specific parameters, that non- composite CSI feedback related to CQI (CQM ), shall be sent and/or transmitted in HS-DPCCH subframes 2, 3 and 4. CPICH1 and CPICH2 in figure 8 may be two different pilot signals CPICH1 and CPICH2. CPICH1 belong to a first cell whereas CPICH2 belongs to a second cell. There is also a wireless device is connected to the first- and second cells. The cells provide HSDPA operation for the wireless device. The wireless device is configured with a first- and a second CQI reporting period (1001 , 1002) and the first- and the second CQI reporting periods (1001 , 1002) are applied in the respective first- and second cells.

The association between the CQI reporting periods and the cells may be defined as if the CQI reporting period may determine the cycle and/or frequency for sending CQI feedback in/for a cell and/or an HSDPA radiolink. The first time slot and/or subframe and/or TTI in which the first CQI feedback is available, may be the first CQI reporting time instance after the encoded CQI feedback is available.

Applying a CQI reporting period may be defined as sending and/or transmitting CQI feedback with a determined periodicity and/or cycle with a known starting- and/or reference subframe and/or TTI and/or time instance. and/or slot in which is applied in the respective cell. The wireless device may measure and/or estimate a SINR on the CPICH (CPICH1 and CPICH2) for each cell involved in the HSDPA operation. The wireless device may thereafter encode and transmit the

corresponding CQI feedback in a certain CQI reporting time instance.

Composite CQI feedback or composite feedback may comprise a jointly encoded CQI feedback, wherein each CQI feedback may be related to different HSDPA radio links and/or cells in e.g. HSDPA operation.

Composite CQI feedback may be sent from the wireless device when a wireless device has determined that the CQI reporting time instance for a first HSDPA radio link and/or first cell coincide with a CQI reporting time instance for a second HSDPA radio link and/or second cell. In figure 8 there is illustrated an example of composite CQI feedback. Based on the CQI reporting periods 1001 , 1002, the wireless device may determine that composite CQI feedback (CQI_C) may be sent in HS-DPCCH subframe 1 and subframe 5. The wireless device may also determine, based on cell specific parameters, that non-composite CSI feedback related to CQI (CQM ), shall be sent and/or transmitted in HS-DPCCH subframes 3. If the wireless device determines that CQI feedback for different cells and/or HSDPA radio links, shall be sent in the same TTI and/or subframe and/or time slots, on the common HS- DPCCH, the CQI reporting time instances are said to coincide.

In a wireless communication system 100, CQI feedback may be blindly decoded.

The blind part in the decoding is caused by not knowing whether the CQI feedback is composite or non-composite. Consequently, blindly decoding CQI feedback may comprise decoding of CQI feedback and obtain at least one bit representation and/or CQI value, reflecting the requested CQI for one or both HSDPA radio links and/or cells. The value obtained after the decoding can be compared with previous values of the output from blindly decoding CQI feedback.

In figure 1 , it is illustrated a wireless communication system 100, wherein the wireless communication system 100 may comprise network nodes 101 , 102, 121 . The network nodes 101 , 102 may be NodeBs according to 3GPP. The NodeBs in

3GPP may provide one or more cells (B1 , B2, B3, C1 , C2, C3).

The cells (B1 , B2, B3, C1 , C2, C3) may provide one or more HSDPA radio links.

In figure 1 , there is also illustrated a wireless device 200 which is connected to two cells (B1 , C1 ) and/or network nodes (101 , 102) for HSDPA operation. Each cell (B1 , C1 ) that is connected to the wireless device in HSDPA operation, provides an

HSDPA radio link (401 , 402).

According to CQI feedback reduction technique, a network node 101 , 102, 121 , may configure a wireless device in HSDPA operation, with several reporting periods, for example a low value for sending frequent CQI feedback and a high value for sending non-frequent CQI feedback at low activity. In an example, illustrated in figure 6, a wireless device 200, may transmit and/or send CQI feedback according to a CQI reporting period with a low value, i.e. for frequent CQI feedback. The wireless device may decode the downlink control channel (HS-SCCH) and based on that decoding the wireless device may determine that no data has been scheduled for the wireless device in the downlink direction during a number of (N) consecutive and/or successive TTI's and/or subframes. The wireless device may, if the number of consecutive TTI's is greater than a threshold value (ThV), assume that there is no more data to be scheduled in the downlink direction on that carrier and/or cell and therefore another, non- frequent- or low activity CQI reporting period is applied. Applying a CQI reporting period may be defined as sending and/or transmitting and/or reporting CQI feedback with a determined periodicity and/or cycle with a known starting- and/or reference subframe and/or TTI and/or time instance. A wireless device (200) may be adapted to have timing relation, in particular a well-defined and/or synchronized timing relation, between the HS-DPCCH subframes and the CPICH in order to be able to transmit and/or send CQI feedback in the proper time slot and/or TTI or subframe after having measured and/or estimated the SINR and/or CQI on the CPICH. The TTI and/or subframe and/or timeslot in which the wireless device sends and/or reports and/or transmits the CQI feedback, may be called a CQI reporting time instance. The wireless device may also be adapted to determine the timing relation between the different CPICH in different cells and the HS-DPCCH. The wireless device may also be adapted to determine the timing relation between the HS-PDSCH and the HS-DPCCH. The wireless device may also be adapted to determine the timing relation between the HS-PDSCH for all HSDPA radio links in HSDPA operation with the wireless device. Consequently, a wireless device which applies a non-frequent CQI reporting period, may whenever it decodes the HS- SCCH and determines that there is scheduled data to come on the HS-PDSCH, it will apply the frequent CQI reporting period, starting from the TTI and/or subframe in which it detected that scheduled data is coming on a HSDPA radio link, or from some reference TTI or subframe.

A wireless device (200) may be adapted to have timing relation, in particular a well-defined and/or synchronized timing relation, between the HS-DPCCH subframes and the CPICH in order to be able to send CQI feedback in the proper time slot. The sending may be done after having estimated SINR based on measurements on the CPICH. The wireless device may also be adapted to know the timing relation between the different CPICH in different cells and the HS- DPCCH. The wireless device may also be adapted to know the timing relation between several HS-PDSCH and/or the HS-DPCCH.

It is disclosed in a first aspect, a method for operating a wireless device, the wireless device being connected to a first- and a second cell with HSDPA operation, the method optionally comprising configuring the wireless device with and/or the wireless device being further configured with a first- and a second CQI reporting period associated with the respective first- and second cell, wherein the method may optionally comprise: determining (S1 ), based on the first- and the second CQI reporting periods, whether to send composite CQI feedback or non- composite CQI feedback; sending (S2) CQI feedback according to said

determination

In a variant of the method, it is determined that composite CQI feedback is sent if a first CQI reporting time instance is equal to a second CQI reporting time instance.

In another variant of the method, it is determined that non-composite CQI feedback is sent if the first CQI reporting time instance is not equal to the second CQI reporting time instance

The method is also disclosed wherein the first- and the second CQI reporting periods are based on HS-DSCH activity associated with the wireless device, in the respective first- and second cells. In a second aspect, a wireless device is disclosed, the wireless device being connectable to a first- and a second cell with HSDPA operation, the wireless device is further optionally adapted to being configured with a first- and a second CQI reporting period associated with the respective first- and second cell, the wireless device being additionally adapted to determine, based on the first- and the second CQI reporting periods, whether to send composite CQI feedback or non-composite CQI feedback and send CQI feedback according to said

determination

A variant of the wireless device is presented wherein the wireless device is further adapted to determine that composite CQI feedback is sent if a first CQI reporting time instance is equal to a second CQI reporting time instance and to determine that non-composite CQI feedback is sent if the first CQI reporting time instance is not equal to the second CQI reporting time instance.

According to some variants the first- and the second CQI reporting periods are based on HS-DSCH activity associated with the wireless device in the respective first- and second cells as disclosed herein.

In a third aspect a method for operating a network node of a wireless

communication network, is disclosed. The network node is controlling at least a first cell, wherein the first cell is connected to a wireless device in HSDPA operation with the cell, wherein the HSDPA operation is in connection with at least a second cell, wherein the method comprises receiving CQI feedback and determining, based on composition conditions, whether the CQI feedback is composite or non-composite CQI feedback.

In some variants, the composition conditions may be based on blind decoding of the CQI feedback.

In one example, it is disclosed that blind decoding is performed by applying a first- and/or a second decoding method, each method generating a first- and second decoded value.

It is also disclosed that the first decoding method is associated with the non- composite CQI feedback and the second decoding method is associated with the composite CQI feedback.

In one variant, the composition condition includes determining whether the first- and/or second decoded values is/are within an expected range and/or greater than an expected value. It may be considered that the expected value and/or the expected range is based on previously decoded CQI feedback.

In another variant, the composition condition may be based on a relation between a first- and a second CQI reporting period associated with the respective first- and second cells.

As an example, the second CQI reporting period, associated with the second cell, may be obtained from and/or via either of:

- a wireless device, which is involved in the HSDPA operation

- a second network node, which is involved in the HSDPA operation - a third network node (RNC)

- the network node

In a variant, the first- and the second CQI reporting periods may be based on HS- DSCH activity associated the respective first- and second cells.

In a fourth aspect, a network node adapted to operate in a wireless communication network is considered. The network node being adaptable to control at least a first cell, wherein the first cell is connected to a wireless device in HSDPA operation wherein the HSDPA operation is connected with at least a second cell wherein the network node being further adaptable to receive CQI feedback and determine, based on composition conditions, whether the CQI feedback is composite or non- composite CQI feedback.

Also there is disclosed a wireless device adapted for being connected to a first- and a second cell with an HSDPA operation, the wireless device is further adapted to being configured with a first- and a second CQI reporting period associated with the respective first- and second cell. The wireless device comprises a determining module, adapted and/or configured to determine, based on the first- and the second CQI reporting periods, whether to send composite CQI feedback or non- composite CQI feedback and a sending module, adapted and/or configured to send CQI feedback according to said determination.

Moreover, there may be considered a network node adapted to operate in a wireless communication network, the network node being adaptable to control at least a first cell, wherein the first cell is connected to a wireless device in HSDPA operation wherein the HSDPA operation is connected with at least a second cell, wherein the network node further comprises a receiving module, adapted and/or configured to receive CQI feedback and a determining module, adapted and/or configured to determine, based on composition conditions, whether the CQI feedback is composite or non-composite CQI feedback.

Generally, there may also be considered a computer program (225; 235) comprising instructions which, when executed on a processing circuitry (210), cause the processing circuitry (210) to carry out and/or control the method according to any one of claims 1 -4. In another aspect, one may consider a computer program (125; 135) comprising instructions which, when executed on a processing circuitry (1 10), cause the processing circuitry (1 10) to carry out and/or control the method according to any one of claims 9-19.

Additionally disclosed is a carrier (120; 130) containing the computer program of claim 33, wherein the carrier is one of an electronic signal, optical signal, radio signal, computer or processing circuitry readable storage medium.

In another variant there is disclosed a carrier (140; 150) containing the computer program of claim 34, wherein the carrier is one of an electronic signal, optical signal, radio signal, computer or processing circuitry readable storage medium. According to embodiments described herein, in figure 9, there is disclosed a method for operating a wireless device 200, the wireless device being connected to a first- and a second cell with HSDPA operation as illustrated in figure 1 , and the wireless device 200 being further configured with a first- and a second CQI reporting period (1001 , 1002) associated with the respective first- and second cell (B1 , C1 ). This can be illustrated by figure 8, in which a first cell (B1 ) has CPICH1 and CQI reporting period 1001 of 4 ms and the second cell (c1 ) has CPICH2 and CQI reporting period 1002 of 8 ms. The method comprises; determining (S1 ), based on the first- and the second CQI reporting periods, whether to send composite CQI feedback or non-composite CQI feedback; sending (S2) CQI feedback according to said determination.

The determining step S1 can be further described as the wireless device determining whether to send composite CQI feedback (CQI_C) if the CQI reporting periods 1001 , 1002, cause the CQI reporting time instances 2001 and 2002, to coincide. On the other hand, it is determined to send non-composite feedback if the CQI reporting periods 1001 , 1002 do not cause the CQI reporting time instances 2001 , 2002 to coincide.

Based on the determination in S1 the wireless device sends CQI feedback.

The determination can also be performed based on CQI reporting time instances for the different cells and/or HSDPA radio links. In such a case, it may be determined that non-composite CQI feedback is sent if the first CQI reporting time instance is not equal to, or does not coincide with, the second CQI reporting time instance.

In another embodiment, the first- and the second CQI reporting periods are based on HS-DSCH activity associated with the wireless device, in the respective first- and second cells. This means that the CQI reporting period, and consequently the CQI reporting time instance, for a cell and/or HSDPA radio link, may vary with the activity on the HS-PDSCH. Since there are one HS-PDSCH and/or HSDPA radio link per cell in HSDPA operation with the wireless device, the CQI reporting period may vary between cells and consequently, the CQI reporting time instances per cell and/or HSDPA radio link may vary and consequently the determination of whether to send composite- or non-composite CQI feedback.

One of the advantages with the embodiments above, is that HS-DPCCH

transmissions, such as transmitting CQI feedback, is reduced which means that the Rise over Termal (RoT) in uplink is lowered. If RoT is lowered, it means that it may be possible to enable higher system throughput capacity or increasing coverage.

In other embodiments, illustrated in figure 10, there is disclosed methods for operating a network node of a wireless communication network, the network node is controlling at least a first cell, wherein the first cell is connected to a wireless device in HSDPA operation with the cell, wherein the HSDPA operation is in connection with at least a second cell, wherein the method comprises receiving (S1 1 ) CQI feedback and determining (S12), based on composition conditions, whether the CQI feedback is composite or non-composite CQI feedback.

In a scenario like this the network node, e.g. a NodeB, does not know if the wireless device has encoded CQI feedback as composite- or non-composite feedback.

Disclosed herein are two alternative methods for determining whether the CQI feedback is composite or non-composite.

A first alternative method may be briefly described as to blindly decode and test the output against an expected value.

E.g. the method may comprise a determining based on blind decoding of the CQI feedback, wherein the blind decoding is performed by applying a first- and/or a second decoding method. Additionally, the first decoding method may be associated with the non-composite CQI feedback and the second decoding method may be associated with the composite CQI feedback.

Additionally and/or alternatively the decoded CQI feedback is tested against a condition, wherein the condition may be to check if the decoded CQI feedback is: - within- or outside an expected range

- greater than, equal to or less than, an expected value A range may be e.g. a weighted average of e.g. the latest received CQI values with a confidence interval wherein the range may be set out by the values representing the limits for the confidence interval.

The range or values that may be used for a test to determine if the blind decoding was performed with a correct decoder, it may also be obtained by some statistical prediction algorithm which is based on a sequence of previously decoded CQI feedback values.

If in the method, the decoded CQI feedback is determined to assume a value outside the expected range of a test and/or below/under a target value, the decoding is repeated with another decoding method, e.g. as exemplified above. In a more specific example if the decoded CQI feedback is blindly decoded, using the first decoding method associated with the non-composite decoding, and the obtained value does not fall within the expected range of valid values, the blind decoding is repeated with the second decoding method, associated with

composite CQI feedback to obtain the decoded CQI feedback value (e.g. CQI: Ό- 31 ').

Another alternative to determine, in a network node, if the CQI feedback is composite or non-composite, may be to determine, based on first- and/or second CQI reporting periods associated with the respective first- and second cells. In such a case the composition condition is based on a relation between the CQI reporting periods and/or CQI reporting time instances.

In this example it is assumed that the network node controlling the cell has obtained the CQI reporting periods and/or CQI reporting time instances for the cells involved in HSDPA operation with the UE. This can be achieved via signalling (e.g. RRC signalling) from the wireless device to the first network node and/or signalling from another network node (e.g. NodeB) which may be serving the other cell in the HSDPA operation operation and/or from or via an RNC connected to the network nodes (NodeB's) involved in the HSDPA operation. If these CQI reporting periods and/or CQI reporting time instances, are known in the cell controlled by the first network node, it is possible to determine if the wireless device have sent composite- or non-composite CQI feedback in certain HS-DPCCH subframes and/or timeslot or timeslots.

FIG. 1 1 is a schematic diagram illustrating an example of a wireless device.

In this particular example, at least some of the steps, functions, procedures, modules and/or blocks described herein are implemented in a computer program 225; 235, which is loaded into the memory 220 for execution by processing circuitry including one or more processors 210. The processor(s) 210 and memory 220 are interconnected to each other to enable normal software execution. An optional input/output device may also be interconnected to the processor(s) and/or the memory to enable input and/or output of relevant data such as input parameter(s) and/or resulting output parameter(s).

The term 'processor' should be interpreted in a general sense as any system or device capable of executing program code or computer program instructions to perform a particular processing, determining or computing task.

The processing circuitry including one or more processors is thus configured to perform, when executing the computer program, well-defined processing tasks such as those described herein.

The processing circuitry does not have to be dedicated to only execute the above- described steps, functions, procedure and/or blocks, but may also execute other tasks.

According to another example, there is provided a computer program 225; 235 comprising instructions, which when executed by at least one processor 210, cause, the at least one processor 210 to: - determine (S1 ), based on the first- and the second CQI reporting periods, whether to send composite CQI feedback or non-composite CQI feedback

- send (S2) CQI feedback according to said determination In yet another example, the proposed technology also provides a carrier 220; 230 comprising the computer program 225; 235, wherein the carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium.

FIG. 12 is a schematic diagram illustrating an example of a network node.

In this particular example, at least some of the steps, functions, procedures, modules and/or blocks described herein are implemented in a computer program 125; 135, which is loaded into the memory 120 for execution by processing circuitry including one or more processors 1 10. The processor(s) 1 10 and memory 120 are interconnected to each other to enable normal software execution. An optional input/output device may also be interconnected to the processor(s) and/or the memory to enable input and/or output of relevant data such as input parameter(s) and/or resulting output parameter(s).

The processing circuitry does not have to be dedicated to only execute the above- described steps, functions, procedure and/or blocks, but may also execute other tasks. According to another example, there is provided a computer program 125; 135 comprising instructions, which when executed by at least one processor 1 10, cause the at least one processor 1 10 to:

- receive CQI feedback - determine, based on composition conditions, whether the CQI feedback is composite or non-composite CQI feedback

In yet another example, the proposed technology also provides a carrier 120; 130 comprising the computer program 125; 135, wherein the carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium.

By way of example, the software or computer program 125; 135; 225; 235 may be realized as a computer program product, which is normally carried or stored on a computer-readable medium 120; 130; 220; 230, in particular a non-volatile medium. The computer-readable medium may include one or more removable or nonremovable memory devices including, but not limited to a Read-Only Memory

(ROM), a Random Access Memory (RAM), a Compact Disc (CD), a Digital Versatile Disc (DVD), a Blu-ray disc, a Universal Serial Bus (USB) memory, a Hard Disk Drive (HDD) storage device, a flash memory, a magnetic tape, or any other conventional memory device. The computer program may thus be loaded into the operating memory of a computer or equivalent processing device for execution by the processing circuitry thereof.

The flow diagram or diagrams presented herein may also be regarded as a computer flow diagram or diagrams, when performed by one or more processors. A corresponding communication station may therefore be defined as a group of function modules, where each step performed by the processor corresponds to a function module. In this case, the function modules are implemented as a computer program running on the processor. Hence, the communication station may alternatively be defined as a group of function modules, where the function modules are implemented as a computer program running on at least one processor.

The computer program residing in memory may thus be organized as appropriate function modules configured to perform, when executed by the processor, at least part of the steps and/or tasks described herein. Figure 13 is a schematic block diagram illustrating an example of a wireless device comprising a group of function modules.

As one example there is provided a wireless device 200, which comprises a determining module 250 and a sending module 260. The determining module 250 is adapted and/or configured to determine, based on the first- and the second CQI reporting periods, whether to send composite CQI feedback or non-composite CQI feedback.

The sending module 260 is adapted and/or configured to send CQI feedback according to said determination Figure 14 is a schematic block diagram illustrating an example of a network node comprising a group of function modules.

As one example there is provided a network node 101 ; 102, which comprises a receiving module 140 and a determining module 160.

The receiving module 140 is adapted and/or configured to receive CQI feedback. The determining module 160 is adapted and/or configured to determine, based on composition conditions, whether the CQI feedback is composite or non-composite CQI feedback.

The embodiments described above are merely given as examples, and it should be understood that the proposed technology is not limited thereto. It will be understood by those skilled in the art that various modifications, combinations and changes may be made to the embodiments without departing from the present scope as defined by the appended claims. In particular, different part solutions in the different embodiments can be combined in other configurations, where technically possible. Transmissions on HS-DPCCH (the common CQI feedback channel) from all wireless devices, contribute to the interference level and the Rise over Thermal (RoT) in uplink . However, there are scenarios where the HS-DPCCH transmissions could be reduced for lowering the RoT and enabling higher system throughput capacity or increasing coverage.

In one HS-DPCCH sub-frame, the Channel-Quality Indicator (CQI) may be transmitted in the 2nd and 3rd slots CQI may be an indicator for HSDPA down-link channel quality. The more frequent the CQI feedback is transmitted, the more reliable input for scheduling decisions in the network. This to maintain a good DL throughput. The CQI may be signaled from a wireless device to a Node B and/or network node on one or several uplink HS-DPCCH physical channels. The HS- DPCCH may reside other channel state information which may depend on configured downlink transmission mode.

Figure 2a shows the messages exchanged between Node-B and a wireless device when the wireless device is configured with only one carrier for HSDPA operation. From the common pilot channels (P-CPICH and S-CPICHs when needed), the wireless device estimates the channel, computes the channel quality information and pre-codes channel indicator. This information along with hybrid ARQ

ACK/NAK may be reported to Node-B using dedicated physical control channel (HS-DPCCH). The structure of an HS-DPCCH for a single carrier is shown in Figure 3 when the wireless device is configured in non MIMO mode. It can be seen from the figure that in the first slot HARQ ACK is transmitted (1 Obits) and in the 2nd and 3rd slots CQI information is transmitted (20 bits). Note that CQI of 5 bits is block encoded (Reed Muller code) to form 20 bits.

Once the Node-B receives the encoded CQI of 20 bits, it allocates the required channelization codes, modulation and coding to the wireless device after scheduling. This information is conveyed to wireless device by shared control channel (HS-SCCH). Once the wireless device detects the HS-SCCH, downlink transmission starts through data traffic channel using Physical Downlink Shared Channel (HS-PDSCH).

Figure 2b shows the message sequence chart for data transmission in a multipoint and /or multi carrier communication system. Note that Node B (101 ) indicates the primary Node B or serving cell and the Node B (102) indicates secondary Node B or the assisted Node B. The pilot channel CPICH (P-CPICH) is sent from each Node B. Note that these pilot signals differ by different scrambling codes. From the individual pilot signals, UE estimates the SINR and the channel quality information are sent through a common feedback channel HS-DPCCH. The HS- DPCCH structure is shown in Figure 3b.

The feedback signaling may consist of Hybrid-ARQ Acknowledgement (HARQ- ACK) and Channel-Quality Indication (CQI) for each link. Each HS-DPCCH sub frame of length 2 ms (3^*2560 chips) consists of 3 slots, each of length 2560 chips. The CQI of the primary link (CQI1 ) and CQI of the secondary link (CQI2) may be jointly encoded using a (20, 10) block code and these 20 bits may be transmitted in the 2nd and 3rd slots. An example of the joint encoding operation of CQI1 and CQI2 is shown in Figure 5a, where the 5 bits of individual CQI of the primary cell is concatenated with the 5 bits of CQI of the secondary link. Then these 10 bits may be passed through the block encoder to form the 20 coded bits. Once each Node B receives the composite CQI information, each Node B schedulers may decode the 10 bits and extract the corresponding CQI for the HSDPA radio link related to the CQI. This CQI information may be used in deciding the modulation information, transport block size, and the number of codes etc. for the next downlink transmission. This information may be sent through the HS-SCCH from each cell. The actual data transmission on HS-PDSCH may start once HS-SCCH is sent (after e.g. 2 slots and/or time slots).

As described in WO 2014/148964 A1 , a wireless device may be configured with two reporting periods, an activity- and a low activity reporting period. For example an RNC (121 ) may configure a wireless device with a short reporting period for frequent reporting at activity (normal or primary) and a high value for non-frequent reporting period at low activity.

A wireless device may report the CQI with an activity reporting period, as long as there may be data to be scheduled on the HS-PDSCH. However, if there is no data to transmit for N successive TTI's and or subframes, then the wireless device may assume that there is no data more to be scheduled in the downlink direction on that carrier and therefore the wireless device may start reporting less

frequently. The different activity states are illustrated in Figure 6. Note that the wireless device may decode the downlink control channel (HS-SCCH) to identify whether it is scheduled or not. The value of N may be configurable by an RNC and/or a NodeB.

When the wireless device is reporting CQI using a low activity reporting period representing, and the wireless device receives and/or decodes HS-SCCH correctly, it may start using and/or applying the activity reporting period starting from that TTI or subframe, of starting the high frequency reporting period at some reference TTI or subframe.

There are a couple of methods to that may be applied in a multicarrier

environment when the wireless device is configured in multipoint transmission.

Use single point solution to indicate the CQI of the other Node B

According to this method, whenever a wireless device may not receive data for a period of N TTIs (or equivalent msec or subframes), the wireless device may move to the low activity reporting cycle for that Node B. However, for the composite CQI feedback, which may be jointly coded as in Figure 3b, instead of 10 bits, only 5 bits are used (before concatenation) as shown in Figure 5b and 5c . In Figure 5b the serving Node B is moved to low activity reporting cycle, while in Figure 5c the assisting Node B is moved to the low activity reporting cycle. When the two Node B's, one is with activity reporting cycle and another one is with low activity reporting cycle, need to report CQI at the same TTI according to its own cycle, i.e., reporting time overlaps for the two Node Bs, then the composite CQI feedback should be constructed as in Figure 5a. As shown in Figure 5b, only the CQI bits correspond to the assisting Node B are encoded to form (20,5) block encoder, thereby improving the Hamming distance of the code, thereby improving the reliability of CQI detection at the receiver.

Similarly in Figure 5c, only the CQI corresponds to the serving Node B are encoded using (20,5) block encode. Whenever the wireless device receives data on the corresponding Node B it will move to activity reporting cycle and the composite CQI report is according to Figure 5a.

According to another method, whenever the wireless device may not receive data for a period of N TTIs (or equivalent msec), it will move to the low activity reporting cycle for that Node B. However for the composite CQI report which is jointly coded as in Figure 5a, instead of 10 bits which are composed of 5+5 bits (that is the CQI is repeated) as shown in Figure 5a, when there is no data on the serving Node B (since it is already moved to the secondary reporting cycle). The main advantage of this method is an additional coding gain provided by the repeated code which in turn improves the reliability of the CQI detection.

In another method, the wireless device may choose to move to the low activity or secondary reporting cycle when there is no data (no HS-SCCH detection) from either of the Node Bs. In another alternative method, the wireless device may chooses to move to the secondary or low activity reporting cycle and may use the composite CQI reporting of (20, 10) when there is no data (no HS-SCCH detection) from any one of the Node Bs.

A CQI reporting period may be defined as a time interval between the starting point of two consecutive CQI reporting time instances associated with one cell.

A CQI reporting time instance may be defined as position in a feedback channel. The feedback channel may be HS-DPCCH. The feedback channel may be per cell. In case of HSDPA operation the HS-DPCCH may be a common feedback channel for all cells in HSDPA operation with the wireless device. The position in the feedback channel may be expressed as a slot and/or slots in a subframe or TTI on feedback channel.

A wireless device may be said to being configured with a CQI reporting period, which may mean that the wireless device is informed by a network node and/or a cell provided by a network node, about a time interval. The time interval may be used to control the time between the starting point of two consecutive CQI reporting time instances associated with one cell. The CQI reporting period and/or the time interval may be expressed in terms of subframes and/or slots and/or TTI's of the feedback channel. If the wireless device is connected to several cells with HSDPA operation, a configuration of CQI reporting period may be done for each cell involved in the HSDPA operation.

A wireless device (200) may be adapted to have timing relation, in particular a well-defined and/or synchronized timing relation, between the HS-DPCCH subframes and the CPICH in order to be able to send CQI feedback in the proper time slot after having measured on the CPICH. The wireless device may also be adapted to know the timing relation between the different CPICH in different cells and the HS-DPCCH. The wireless device may also be adapted to know the timing relation between the HS-PDSCH and/or the HS-DPCCH. CQI feedback may be composite- and/or non-composite CQI feedback. Composite CQI feedback may comprise a jointly encoded CQI feedback, wherein each CQI feedback value may be related to different cells and/or HSDPA radio links in e.g. HSDPA operation. Composite CQI feedback may be sent from the wireless device when a wireless device has determined that the CQI reporting time instance for a first cell coincide with a CQI reporting time instance for a second HSDPA radio link. A first CQI reporting time instance may be determined based on a first CQI reporting period and/or a reference TTI or subframe. A second CQI reporting time instance may be determined based on a second CQI reporting period and/or a reference subframe. If the CQI reporting time instances coincide, they may be said to be equal.

In figure 8 there is illustrated an example of composite CSI feedback. Based on the cell specific parameters the wireless device may determine that composite CSI feedback related to CQI (CQI_C) may be sent in HS-DPCCH subframe 1 and subframe 5. The wireless device may also determine, based on cell specific parameters, that non-composite CSI feedback related to CQI (CQM ), shall be sent and/or transmitted in HS-DPCCH subframes 2, 3 and 4. A CSI feedback may be blindly decoded. The blind part in the decoding is caused by not knowing whether the CSI feedback is composite or non-composite.

Consequently, blindly decoding CSI feedback may comprise decoding of CSI feedback and obtain at least one bit representation and/or CSI value, reflecting the requested CSI for one or both HSDPA radio links and/or cells and/or network nodes. The value obtained after the decoding can be compared with previous values of the output from blindly decoding CSI feedback. CQI may be sent periodically or aperiodically.

Figure 1 is a general illustration of a wireless device (200) in HSDPA operation in a wireless communication network (100). The network nodes (101 , 102) may control a number of cells (B1 -B3, and C1 -C3) which in turn may be connected and/or connectable to the wireless device via radio links. The network nodes (101 , 102) may be NodeB's in a 3GPP UTRAN (Universal Terrestrial Radio Access Network).

In HSDPA operation the wireless device may be connected to the network nodes (101 , 102) via at least two cells (B1 -B3, and C1 -C3) each cell may be controlling an HSDPA radio link (401 , 402) which are operating on the same frequency. The HSDPA radio links may carry user data and signaling data between the wireless device and the network nodes. It may also carry information on feedback regarding channel quality, which may be called CQI feedback.

Figure 2 shows the message sequence chart for data transmission in an HSDPA scenario. The P-Node B (101 ) in the figure may be the called the primary Node B and may be controlling the serving HS-DSCH cell (B1 ) and the S-Node B (102) may indicate the secondary Node B and may be controlling the assisting serving HS-DSCH cell (C1 ). The pilot channel CPICH (P-CPICH) is sent from each Node B (101 , 102). These pilot signals may differ only by different scrambling codes. From the individual pilot channels, the wireless device (200) may estimate SINR (Signal to Interference and Noise Ratio) and based on that estimate, the wireless device (200) may send the channel quality information (CQI feedback) through a common feedback channel, the HS-DPCCH.

The HS-DPCCH structure is shown in Figure 3 and the HS-DPCCH structure for composite CQI (CQI_C) is shown in Figure 4. In case of HSDPA operation with e.g. two cells, the HS-DPCCH may be a common feedback channel for both cells. Therefore, both cells in HSDPA operation have a common view of the uplink timing. This means that both cells have a common view of the absolute time instance in terms of uplink

synchronization of subframes. The CQI reporting time instance on the HS-DPCCH may be determined in relation to when a measurement has been performed on the CPICH in a cell.

The feedback signaling may consist of Hybrid-ARQ Acknowledgement (HARQ- ACK) and/or Channel-Quality Indication (CQI) for each HSDPA radio link. The feddback signalling may be based on the HS-PDSCH data transmitted in the same downlink (DL) subframe, on each HSDPA radio link, from the network node (101 , 102) towards the wireless device (200). The HS-DPCCH feedback is sent in the uplink (UL), meaning that it is sent from the wireless device (200) to the network nodes (101 , 102) and/or cells (B1 -B3, C1 -C3), and each UL sub frame may be of length 2 ms and may consist of 3 slots or timeslots. The HARQ-ACK for the first HSDPA radio link (401 ) and the second HSDPA radio link (402) may be

jointly/compositely encoded into a composite HARQ-ACK of 10 bits (HARQ- ACK_C) and are transmitted in the first slot of the first HS-DPCCH sub-frame (600).

Similarly, the CQI of the first HSDPA radio link (401 ) and the CQI of the second HSDPA radio link (402) are jointly encoded into a composite CQI (CQI_C) of 20 bits by using a (20, 10) block code. These 20 bits are transmitted in the 2nd and 3rd slots. An example of the concatenation of the two CQIs representing the first HSDPA radio link (CQI1 ) and the second HSDPA radio link (CQI2), is shown in figure 5. The concatenation may be performed by concatenating the 5 bits representing CQI1 with the five bits representing CQI2, into a 10 bit sequence prior to passing the 10 bits through the block encoder to form the 20 encoded bits, i.e. a (20, 10) block code.

In HSDPA operation, there may only be one HSDPA radio link and consequently no concatenation of CQIs is required and this may be one scenario when non- composite CQI feedback is sent. In this case only 5 bits, representing the CQI, are passed through the block encoder to form the 20 bits that will fit into 2^nd and 3^rd slots of the subframe and therefore a (20,5) block encoding may be said to have been used when encoding non-composite CQI feedback. In general, this gives a more robust encoding of the CQI in the sense that less power is required to transmit the information at the same likelihood of decoding the value correctly at the receiver.

According to a CSI reduction technique, the RNC (121 ) may, configure the wireless device (200) with two different CQI reporting periods. For example the RNC (121 ) may configure a low value for frequent- or normal activity CQI reporting and a high value for non-frequent CQI reporting, wherein the non-frequent CQI reporting may aim at reducing the UL interference at low activity on the HS- PDSCH, i.e. at low user data activity on the downlink.

When the wireless device (200) is configured for CSI reduction, the wireless device (200) sends CQI feedback with a normal reporting period. However, if no data is scheduled and/or transmitted on the HS-PDSCH during a number of, N, successive subframes, the wireless device (200) may assume that there is no data to be scheduled in the downlink direction on that HSDPA radio link carrier and the wireless device (200) transits to a state with a less frequent CQI feedback transmissions. This transition may mean that the wireless device applies a CQI reporting period for low activity based on the activity on the HS-PDSCH and/or based on the normal activity CQI reporting period and/or another value signaled to the wireless device from a network node and/or a NodeB. When the wireless device, applies another CQI reporting period in one of the HSDPA radio links and/or one of the cells, the wireless device may be said to be configured with a CQI reporting period. This state may be called a low activity state. This is illustrated in figure 9. Note that the UE decodes the downlink control channel (HS-SCCH) to identify whether any data is scheduled or not. The value of N may be configured by the RNC (121 ) and/or a network node (101 , 102) during the data call setup in order for the network and the wireless device to know the conditions and/or rules for state transitions from inactivity to activity. An alternative to the rules is that the wireless device signals to the NodeB at or in relation to state transitions to and/or from low activity.

When the wireless device (200) is in low activity state, i.e. reporting CQI with non- frequent CQI reporting period, the wireless device may, whenever it receives and/or decodes the HS-SCCH correctly, it may move to the frequent CQI reporting period, wherein the reporting period may start at that first subframe or at a later subframe with some offset (K) from the first subframe.

In HSDPA operation on the other hand, there may be two HSDPA radio links in two different cells and consequently one CQI from each cell may be reported and or fed back to the corresponding cell (B1 -B3, C1 -C2) and/or network node (101 , 102). Consequently, if the above described CSI reduction technique is applied in HSDPA operation, there is a possibility there are different CQI reporting periods in the two different cells. The difference in reporting periods may cause the time instance and/or subframe and/or time slots to not coincide.

This may be the case if no data is scheduled in one of the cells while data is scheduled in the other. Since the feedback channel is common and it is HSDPA operation, the wireless device (200) shall provide CQI on the common feedback channel (HS-DPCCH) according to the requested feedback. In this scenario, there is an advantage to only send CQI feedback for the cell and/or HSDPA radio link with activity but not include any CQI for the HSDPA radio link and/or cell with no activity. This has the advantage of increasing the robustness of the sent CQI feedback.

In HSDPA operation there may be several HSDPA radio links and/or cells, associated with one wireless device. Each HSDPA radio link and/or cell in HSDPA operation may be associated with a CQI feedback. A reporting time instance for CQI may be configured per cell and/or HSDPA radio link.

CQI may be defined as the bit representation and/or the value of e.g. the

estimated and/or measured SINR measurement. CQI feedback, on the other hand, may be defined as the output from an encoding procedure in which a certain number of information bits, k, is encoded into n bits wherein the n bits may be generated by encoding of a CQI value and/or bit representation of the CQI. The CQI feedback may be defined as the content fitting into a certain position on a feedback channel.

Sending- or reporting- or transmitting CQI feedback from the wireless device may be defined as transmitting encoded bits on the HS-DPCCH reflecting channel quality for an HSDPA radio link or cell in HSDPA operation with the wireless device.

As an example, the CQI feedback may be encoded into 20 bits and sent in slot 2 and 3 in an HS-DPCCH subframe.

In uplink HSPA all wireless device are transmitting using same spreading codes and wireless device are separated by non-orthogonal scrambling codes. This results that wireless device in uplink HSPA transmissions need to share an interference limited resource. Reducing the interference in uplink frequencies is thereby critical to ensure high SIR levels on uplink transmission channel and to maintain a stable system operation.

In one HS-DPCCH sub-frame, the Channel-Quality Indicator (CQI) is transmitted in the 2nd and 3rd slots, and is the key indicator for HSDPA down-link channel quality and its frequent reporting is essential to maintain a good DL throughput. The CQI is signaled from UE to Node B on one or several uplink HS-DPCCH physical channels, together with other channel state information, depending on configured downlink transmission mode. In this disclosure, HSDPA operation may include any kind of operation for which there is an HS-PDSCH channel configured for the wireless device. Some examples of HSDPA operation may be e.g. HSDPA multipoint operation, HSDPA multicarrier operation, HSDPA MIMO operation, MP-multiflow operation, MF- or multipoint HSDPA operation.

Claims

1 . A method for operating a wireless device, the wireless device being connected to a first- and a second cell with HSDPA operation, the wireless device being further configured with a first- and a second CQI reporting period associated with the respective first- and second cell, wherein the method comprises:

- determining (S1 ), based on the first- and the second CQI reporting periods, whether to send composite CQI feedback or non-composite CQI feedback

- sending (S2) CQI feedback according to said determination

2. A method according to claim 1 , wherein it is determined that composite CQI feedback is sent if a first CQI reporting time instance is equal to a second CQI reporting time instance.

3. A method according to claim 1 , wherein it is determined that non- composite CQI feedback is sent if the first CQI reporting time instance is not equal to the second CQI reporting time instance

4. A method according to claims 1 -3, wherein the first- and the second CQI reporting periods are based on HS-DSCH activity associated with the wireless device, in the respective first- and second cells.

5. A wireless device connectable to a first- and a second cell with HSDPA operation, the wireless device is further adapted to being configured with a first- and a second CQI reporting period associated with the respective first- and second cell, the wireless device being additionally adapted to:

- determine, based on the first- and the second CQI reporting periods, whether to send composite CQI feedback or non-composite CQI feedback

- send CQI feedback according to said determination

6. A wireless device according to claim 5, wherein the wireless device is further adapted to determine that composite CQI feedback is sent if a first CQI reporting time instance is equal to a second CQI reporting time instance.

7. A wireless device according to claim 5, wherein the wireless device is further adapted to determine that non-composite CQI feedback is sent if the first CQI reporting time instance is not equal to the second CQI reporting time instance.

8. A wireless device according to claims 5-7, wherein the first- and the second CQI reporting periods are based on HS-DSCH activity associated with the wireless device in the respective first- and second cells.

9. A method for operating a network node of a wireless communication network, the network node is controlling at least a first cell, wherein the first cell is connected to a wireless device in HSDPA operation with the cell, wherein the HSDPA operation is in connection with at least a second cell, wherein the method comprises:

- receiving CQI feedback

- determining, based on composition conditions, whether the CQI feedback is composite or non-composite CQI feedback

10. A method according to claim 9, wherein the composition conditions is based on blind decoding of the CQI feedback.

1 1 . A method according to claim 10, wherein the blind decoding is

performed by applying a first- and/or a second decoding method, each method generating a first- and second decoded value

12. A method according to claim 1 1 , wherein the first decoding method is associated with the non-composite CQI feedback and the second decoding method is associated with the composite CQI feedback

13. A method according to any of claims 10-12, wherein the composition condition includes determining whether the first- and/or second decoded values is/are:

- within an expected range and/or greater than an expected value

14. A method according to claim 13, wherein the expected value and/or the expected range is based on previously decoded CQI feedback.

15. A method according to any of claims 9-14, wherein the composition condition is based on a relation between a first- and a second CQI reporting period associated with the respective first- and second cells.

16. A method according to claim 15, wherein the second CQI reporting period, associated with the second cell, is obtained from and/or via either of:

- a wireless device, which is involved in the HSDPA operation - a second network node, which is involved in the HSDPA operation

- a third network node (RNC)

- the network node

17. A method according to claims 15-16, wherein the first- and the second CQI reporting periods are based on HS-DSCH activity associated the respective first- and second cells.

18. A network node adapted to operate in a wireless communication network; the network node being adaptable to control at least a first cell, wherein the first cell is connected to a wireless device in HSDPA operation wherein the HSDPA operation is connected with at least a second cell wherein the network node being further adaptable to:

- receive CQI feedback

- determine, based on composition conditions, whether the CQI feedback is composite or non-composite CQI feedback

19. A network node according to claim 18, wherein the composition condition is based on blind decoding of the CQI feedback.

20. A network node according to claim 19, wherein the blind decoding is performed by applying a first- and/or a second decoding method, each method generating a first- and second decoded value

21 . A network node according to claim 20, wherein the first decoding method is associated with the non-composite CQI feedback and the second decoding method is associated with the composite CQI feedback

22. A network node according to any of claims 19-21 , wherein the composition condition includes determining whether the first- and/or second decoded values is/are: - within an expected range and/or

- greater than an expected value

23. A network node according to claim 22, wherein the expected value and/or the expected range is/are based on previously decoded CQI feedback.

24. A network node according to any of claims 18-23, wherein the composition condition is based on a relation between a first- and a second CQI reporting period associated with the respective first- and second cells.

25. A network node according to claim 24, wherein the network node is adaptable to obtain a reporting period associated with the second cell, wherein the reporting period is obtained from and/or via either of: - a wireless device, which is involved in the HSDPA operation

- a second network node, which is involved in the HSDPA operation

- a third network node (RNC) the network node

26. A network node according to claims 24-25, wherein the first- and the second CQI reporting periods are based on HS-DSCH activity associated the respective first- and second cells.

27. A wireless device adapted for being connected to a first- and a second cell with an HSDPA operation, the wireless device is further adapted to being configured with a first- and a second CQI reporting period associated with the respective first- and second cell. The wireless device comprises:

- a determining module (250), adapted and/or configured to determine, based on the first- and the second CQI reporting periods, whether to send composite CQI feedback or non-composite CQI feedback

- a sending module (260), adapted and/or configured to send CQI feedback according to said determination

28. A network node adapted to operate in a wireless communication network, the network node being adaptable to control at least a first cell, wherein the first cell is connected to a wireless device in HSDPA operation wherein the HSDPA operation is connected with at least a second cell, wherein the network node further comprises:

- a receiving module (140), adapted and/or configured to receive CQI feedback

- a determining module (160), adapted and/or configured to determine, based on composition conditions, whether the CQI feedback is composite or non-composite

CQI feedback

29. A computer program (225; 235) comprising instructions which, when executed on a processing circuitry (210), cause the processing circuitry (210) to carry out and/or control the method according to any one of claims 1 -4.

30. A computer program (125; 135) comprising instructions which, when executed on a processing circuitry (1 10), cause the processing circuitry (1 10) to carry out and/or control the method according to any one of claims 9-17.

31 . A carrier (220; 230) containing the computer program of claim 29, wherein the carrier is one of an electronic signal, optical signal, radio signal, computer or processing circuitry readable storage medium.

32. A carrier (120; 130) containing the computer program of claim 30, wherein the carrier is one of an electronic signal, optical signal, radio signal, computer or processing circuitry readable storage medium.