WO2011135916A1

WO2011135916A1 - Base station, user equipment and method for transmitting physical uplink control information

Info

Publication number: WO2011135916A1
Application number: PCT/JP2011/054680
Authority: WO
Inventors: Zeng YANG; Renmao Liu; Yingyu Zhang; Yongming Liang; Ming Ding
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2010-04-30
Filing date: 2011-02-23
Publication date: 2011-11-03
Also published as: CN102238747A

Abstract

The present invention discloses a method for transmitting physical uplink control information, a base station (BS) and a user equipment (UE), combining channel information feedback based on non-periodic PUSCH and channel information feedback based on periodic PUCCH. The BS activates reception of one or more downlink Secondary Component Carriers (SCCs) by the UE, and notifies the UE of resources for non-periodic transmission of uplink control information. The UE jointly codes Channel State Indicators (CSIs) for downlink Component Carriers (CCs) including a downlink SCC and/or a downlink Primary Component Carrier (PCC) and transmits them to the BS by using the resources. The BS performs a downlink scheduling based on the CSIs. The UE feeds CSIs for the downlink CCs back to the BS periodically, such that the BS can track variation in the CSIs for the downlink CCs. With the present invention, it is possible to address challenges in designs for transmitting physical uplink control information in the LTE R-10 system.

Description

DESCRIPTION

TITLE OF INVENTION

BASE STATION, USER EQUIPMENT AND METHOD FOR TRANSMITTING PHYSICAL UPLINK CONTROL INFORMATION

TECHNICAL FIELD

The present invention relates to the field of mobile communication technology, and more particularly, to a method for transmitting physical uplink control information in a LTE-Advanced system and a 4G system where Carrier Aggregation (CA) technique is applied, as well as corresponding base station (BS) and user equipment (UE) .

BACKGROUND ART

In the wireless communication system based on 3GPP Long Term Evolution (LTE) Release-8 (R-8) , there are three types of physical uplink control channel information: Scheduling Request (SR) , Hybrid Automatic ReQuest Retransmission (HARQ) feedback information

(ACKnowledgement/ Negative ACKnowledgement,ACK/ NACK) and Channel State Indicator (CSI) feedback. The CSI feedback further includes Channel Quality Indicator (CQI) , Precoding Matrix Indicator (PMI) and Rank Indicator (RI) . In the LTE R-8, the HARQ feedback can be transmitted over the Physical Uplink Control CHannel (PUCCH) and the CSI feedback can be transmitted over the PUCCH periodically. Alternatively, when it is required to transmit the CSI feedback and/ or HARQ feedback along with data, the CSI feedback and/ or HARQ feedback can be multiplexed with the data onto the Physical Uplink Shared CHannel (PUSCH) for transmission. Alternatively, when the BS has a special requirement for channel information, the BS may request the UE to transmit the CSI feedback in a non-periodic manner over uplink PUSCH resources allocated by the BS.

The method for multiplexing the data with the physical uplink control information onto the PUSCH for transmission in LTE R-8 (cf. TS 36.212 V8.7.0, "Evolved Universal Terrestrial Radio Access (E-UTRA) ; Multiplexing and channel coding", Section 5.2.2.8) will be detailed below with reference to Fig. 9.

The ACK/ NACK information occupies at most 4 DFT-SOFDM symbols, i.e. , 4 columns. It is to be noted that, since the DFT-SOFDMA information is input in the time domain, the sub-carriers shown in Fig. 9 are not actual frequency domain sub-carriers. Rather, they are virtual sub-carriers, i. e. , the signals input to DFT.

ACK/ NACK Information

-The ACK/ NACK information is mapped onto both sides of a pilot, starting from the lower side. Data at the corresponding locations are punctured as shown in Fig. 9.

-The ACK/ NACK within one sub-frame may occupy at most 4 SC-FDMA symbols.

-In transmission of 2-bit ACK/ NACK information, a (3 , 2) coding scheme similar to PCFICH can be utilized [3GPP R l -082086] .

RI Information

-The RI and the CQI are separately coded.

-A simple (3, 2) coding is used for a 2-bit situation.

-The RI bits are located at the column adjacent to the ACK information, i.e. , one column away from the pilot. The location of the RI is fixed regardless of the presence / absence of the ACK information.

-Rate matching is made for data puncturing.

CQI Information

-The CQI information is placed at the start of the data resources, first the time domain, then followed by the frequency domain.

-A 8-bit CRC is employed.

-The following channel coding schemes are assumed. For "large" CQI information (more than 10- 14 bits) , a convolutional coding plus rate matching scheme of both the PBCH and the PDCCH can be applied. For "small" CQI information, a block coding scheme of the PUCCH can be applied. The same modulation scheme is applied to the CQI / PMI information and the data transmitted over the PUSCH . The offset between the coding rates of the data MCS and the control information (A/ N and CQI) can be configured in a semi-static manner.

The CA technique is introduced into the 3GPP LTE-Advanced system (also referred to as LTE R- 10) . That is, two or more Component Carriers (CCs) can be aggregated to support an uplink/ downlink transmission bandwidth larger than 20MHz.

According to the discussion in 3GPP TSG RAN I Conference #58, two alternative downlink control channel structures for the LTE-Advanced system are retained (cf. Way

Forward on PDCCH for Bandwidth Extension in LTE-A , R l -093699 , RAN I #58 , Alcatel- Lucent et.al. , August 2009) . The first one is an intra-carrier indication structure in which the Downlink Control Information (DCI) in the Physical Downlink Control CHannel (PDCCH) of a component carrier is dedicated for indicating resource allocation information for that carrier. The second one is a inter-carrier indication structure in which the PDCCH DCI of a component carrier can be used for indicating resource allocation information for that and other component carriers. According to the discussion on 3GPP TSG RAN 1 Conference #59 , a Carrier Indicator Field (CIF) with a fixed length of 3 bits can be introduced into the DCI of the second type of downlink control channel structure as mentioned above, for implementing inter-carrier indication (cf. R l - 10xxxx, Draft Report of 3GPP TSG RAN WG 1 #59 vO .2.0, RAN I #59 , 3GPP, November 2009) . That is, the status of one of the CIF bits represents one CC.

During the standardization of 3GPP LTE R- 10, there are currently the following conclusions on CA (cf. 3GPP RAN2 , Report of 3GPP TSG RAN WG2 meeting #69 , 3GPP, 2010) :

-A concept of Primary Component Carrier (PCC) is introduced into LTE R- 10;

-The uplink PCC and the downlink PCC are configured by the UE;

-The uplink PCC is used to transmit uplink control information for Layer 1 ;

-The downlink PCC can not be deactivated;

-A well-configured CC which is not PCC can be referred to as Secondary Component Carrier (SCC) ; and

-The explicit Media Access Control (MAC) signaling is used to activate/ deactivate the well-configured downlink CC. During the standardization of 3GPP LTE R-10, there are currently the following conclusions on CSI feedback (cf. Final Report of 3GPP TSG RAN WGl #58bis vl.0.0, 3GPP, 2009):

The periodic CSI report is required to support up to 5 downlink CCs:

-It is mapped onto a UE-specific uplink CC in a semi-static manner;

-It follows the principles for reporting CQI/PMI/RI in accordance with LTE R-8; and

* Approaches for reducing report overhead are considered, such as downlink CC cycling; and

* Approaches for supporting increased CSI payload are considered. During the standardization of 3GPP LTE R-10, there are currently the following conclusions on ACK/NACK feedback (cf. 3GPP RANI, Draft Report of 3GPP TSG RAN WGl #60 vO.1.0, 3GPP, 2010):

The following ACK/NACK multiplexing approaches will be further discussed:

-PUCCH Format lb, with the Spreading Factor (SF) reduced to 2 or 1;

-Channel selection based on PUCCH Format la/ lb;

-PUCCH Format 2; and

-A new PUCCH signal or format (such as based on DFT-S-OFDM) .

A UE-specific uplink CC is semi-statically configured for carrying the PUCCH ACK/ NACK, SR and periodic CSI for the UE.

In addition, there are the following conclusions closely associated with the standardization (cf. 3GPP RAN I , Final Report of 3GPP TSG RAN WG 1 #58bis v l .0.0 , 3GPP, 2009) :

The design of ACK/ NACK feedback is not optimized for the scenario in which multiple downlink CCs are simultaneously scheduled by a large amount of UEs.

The above assumption shows that the UE only uses a single downlink CC in most cases and is only occasionally scheduled to use multiple downlink CCs.

In the LTE R-8, the CSI feedback and the ACK/ NACK feedback may collide with each other, as it is required to transmit the CSI and the ACK/ NACK simultaneously (i. e. , in a single sub-frame) . A solution for this problem in the LTE R-8 is to place the ACK/ NACK in Reference Signal (RS) of the PUCCH Format 2 / 2a/ 2b in which the CSI is transmitted, so as to transmit the ACK/ NACK and the CSI simultaneously. In the LTE R- 10, more CSI feedbacks are required to support multiple downlink CC transmissions, which leads to an increased probability that the CSI and the ACK/ NACK will collide with each other. Further, the existing collision solution schemes are no longer applicable due to the increased ACK/ NACK payload. Therefore, there is a need for designing a new method for transmitting physical uplink control information.

The overhead for CSI feedback can be reduced by periodically cycling the feedback of CSI. However, for a UE primarily using a single downlink CC, it is not desirable for the initial scheduling to feed back the CSIs for a number of downlink SCCs, which are just activated, by applying the periodic cycling approach.

SUMMARY OF INVENTION

In view of the challenges in designing a method for transmitting the physical uplink control information for the LTE R- 10 system, it is an object of the present invention to provide various methods for transmitting physical uplink control information in the LTE Advanced system, as well as respecitve base station (BS) and user equipment (UE) .

According to a solution of the present invention, a method for transmitting physical uplink control information is provided, which comprises the following steps of: activating, by a Base Station (BS) , reception of one or more downlink Secondary Component Carriers (SCCs) by a User Equipment (UE) ; notifying, by the BS, the UE of resources for non-periodic transmission of uplink control information; jointly coding, by the UE, Channel State Indicators (CSIs) for downlink Component Carriers (CCs) including a downlink SCC and/ or a downlink Primary Component Carrier (PCC) and transmitting the coded CSIs to the BS by using the resources; performing, by the BS, a downlink scheduling based on the CSIs; and feeding, by the UE, CSIs for the downlink CCs back to the BS periodically, such that the BS can track variation in the CSIs for the downlink CCs.

According to another solution of the present invention, a Base Station (BS) is provided, which comprises: a transceiver unit for activating reception of one or more downlink Secondary Component Carriers (SCCs) by a User Equipment (UE) and notifying the UE of resources for non-periodic transmission of uplink control information; and a resource allocating and scheduling unit for performing downlink scheduling based on Channel State Indicators (CSIs) for downlink channels fed back from the UE, wherein the transceiver unit is configured for receiving CSIs for downlink Component Carriers (CCs) including a downlink SCC and/ or a downlink Primary Component Carrier (PCC) as transmitted from the UE by using the resources, the resource allocating and scheduling unit is configured for performing the downlink scheduling based on the CSIs, and the transceiver unit is further configured for receiving CSIs for the downlink CCs fed back from the UE periodically, such that the BS can track variation in the CSIs for the downlink CCs.

According to yet another solution of the present invention, a User Equipment (UE) is provided, which comprises: a transceiver unit for receiving a notification of activation to receive one or more downlink Secondary Component Carriers (SCCs) and a notification of resources for non-periodic transmission of uplink control information by the UE; a Channel State Indicator (CSI) acquisition unit for acquiring CSIs for downlink Component Carriers (CCs) including a downlink SCC and/ or a downlink Primary Component Carrier (PCC) ; and a coding unit for jointly coding the CSIs for the downlink CCs including the downlink SCC and/ or the downlink PCC, wherein the transceiver unit is configured for transmitting the jointly coded CSIs to a Base Station (BS) and then feeding the CSIs for the downlink CCs back to the BS periodically, such that the BS can track variation in the CSIs for the downlink CCs.

In this way, flexible and efficient solutions are provided in view of the challenges in designing a method for transmitting the physical uplink control information for the LTE R- 10 system.

BRIEF DESCRIPTION OF DRAWINGS

The above and other objects, features and advantages of the present invention will be more apparent from the following preferred embodiments illustrated with reference to the figures, in which:

Fig. 1 is a schematic block diagram showing a BS and a UE in a communication system according to an embodiment of the present invention;

Fig. 2 is a flowchart showing a method for transmitting physical uplink control information according to an embodiment of the present invention, in which non-periodic PUSCH transmission and periodic PUCCH / PUSCH transmission are combined;

Fig. 3 shows a CSI cycling approach according to an embodiment of the present invention;

Fig. 4 shows another CSI cycling approach according to an embodiment of the present invention;

Fig. 5 shows a grouping scheme for downlink CCs according to an embodiment of the present invention;

Fig. 6 shows another grouping scheme for downlink CCs according to an embodiment of the present invention;

Fig. 7 shows a method for increasing the amount of PDCCH information in LTE R- 10 according to an embodiment of the present invention;

Fig. 8 shows a method for implicitly indicating a CFI of a CRC mask code based on PDCCH for inter-carrier scheduling according to an embodiment of the present invention; and

Fig. 9 is a schematic diagram showing a specific method for multiplexing data with physical uplink control information onto PUSCH for transmission in the LTE R-8.

DESCRIPTION OF EMBODIMENTS

For clear and detailed explanation of the implementation steps of the present invention, some specific examples applicable for a wireless communication system supporting CA technique (particularly the LTE Advanced cellular mobile communication system) are given below. Herein, it is to be noted that the present invention is not limited to the application exemplified in the embodiments. Rather, it is applicable to other related wireless communication systems.

Preferred embodiments of the present invention will be detailed with reference to the drawings. In the following description, details and functions unnecessary to the present invention are omitted so as not to obscure the concept of the invention.

In the following, a method which combines non-periodic PUSCH transmission with periodic PUCCH/PUSCH transmission is applied for transmission of CSI feedback from UE to BS. The transmission of CSI feedback based on non-periodic

PUSCH mainly applies to a scenario in which, for a UE, when just activating a number of downlink CCs, it is required to acquire the CSIs for these CCs for downlink scheduling for these downlink CCs, and to a scenario in which another BS requires to acquire detailed CSIs for downlink CCs of a UE.

The transmission of CSI feedback based on periodic PUCCH/PUSCH mainly applies to acquisition of CSIs of downlink CCs other than the above scenarios.

The First Embodiment

In this embodiment, it is scheduled such that the DCI of PDCCH for non-periodic PUSCH transmission is transmitted in the downlink PCC only. The transmission of uplink CSI feedback includes transmission based on non-periodic PUSCH and transmission based on periodic PUCCH/PUSCH, each of which is carried out in the uplink PCC.

Fig. 1 is a schematic block diagram of a BS and a UE in a communication system according to an embodiment of the present invention. It can be appreciated by those who skilled in the art that the system shown in Fig. 1 may comprise more UEs which are omitted herein since they have substantially the same structure as that of the UE as shown in Fig. 1 .

In addition, for clear and concise explanation of the solution of the present invention, only components of the BS and the UE which are relevant to the present invention are illustrated in Fig. 1 , while other conventional components are omitted. In the following, the description of these conventional components are also omitted to avoid any affects caused by unnecessary contents.

As shown in Fig. 1 , the BS 100 according to the embodiment of the present invention comprises a transceiver unit 104 , a control unit 101 , a resource allocating and scheduling unit 102 and a memory unit 103.

The transceiver unit 104 of the BS 100 is configured to transmit/ receive information to/ from the UE 200, under control of the control unit 101 . For example, the transceiver unit 104 may transmit to the UE 200 information such as data and control signaling and receive from the UE data or feedback information such as CSI. The memory unit 103 is configured for storing data or other information, such as configuration information, scrambling sequences and the like.

The resource allocating and scheduling unit 102 is configured to perform resource allocation and scheduling under control of the control unit 101 , such as allocation, configuration, reconfiguration and release operations for PUCCH resources (including information such as resource indications, various time offsets and the like) .

On the other hand, the UE 200 according to the present invention comprises a transceiver unit 205, a CSI acquisition unit 201 , a coding unit 202 , a timer 203 and a control unit 204.

Next, the operation processes of the above devices will be detailed with reference to Fig. 2. Fig. 2 shows a method for transmitting physical uplink control information, in which non-periodic PUSCH transmission and periodic PUCCH / PUSCH transmission are combined.

At step 101 , the BS activates reception of a number of downlink SCCs by the UE.

In the LTE R- 10 system incorporating the CA technique, except for downlink PCC, the reception of the SCCs by the UE is always activated by the BS. Particularly, the BS transmits an activation signaling to the UE, in which signaling there is one bit for each of the SCCs, indicating to the UE whether to start receiving downlink transmission signals of that SCC or not. Upon reception of this activation signaling, the UE determines, based on the status of a bit in the activation signaling which corresponds to a particular SCC, whether to start receiving downlink signals of that SCC or not. Although it is not necessary to activate the downlink PCC, in the context of the present invention, the activated (downlink) CCs generally refer to the downlink PCC and the activated downlink SCCs collectively.

Under control of the control unit 10 1 , the transceiver unit 104 of the BS 100 notifies the UE 200 to start receiving signals of some inactive downlink SCCs via the downlink PCC or another activated SCC, by using Layer 1 activation signaling carried in a PDCCH, Layer 2 activation signaling carried in a MAC Control Element (CE) or Layer 3 activation signaling (also referred to as Radio Resource Control (RRC) signaling) carried in a Physical Downlink Shared CHannel (PDSCH) . Herein, upon reception of such signaling, the UE acknowledges to the BS the correct reception of the activation signaling, which means that the reception for these inactive SCCs has been activated.

At step 102 , the BS notifies the UE of resources for transmission of uplink control information.

After activating the UE 200 to receive the inactive SCCs, the resource allocating and scheduling unit 102 of the BS 100 needs to acquire CSIs for these inactive SCCs, so as to perform downlink scheduling for these inactive SCCs. In order to acquire these CSIs as soon as possible, transmission based on non-periodic PUSCH can be used. The BS can notify the UE of uplink resources for these non-periodic PUSCHs in a variety of ways. For example, the transceiver unit 104 of the BS 100 can embed indication information for these resources into the activation signaling as describe above, so as to notify the UE of the resources for transmitting uplink CSIs at the same time as activation of the SCCs. Alternatively, after confirming the correct reception of the activation signaling by the UE, the transceiver unit 104 of the BS 100 can notify the UE via the PCC or activated SCC by using an additional Layer 1 , Layer 2 or Layer 3 signaling. Herein, an example of the additional Layer 1 signaling is Uplink (UL) Grant control information as defined for PDCCH DCI in the LTE R-8, with the CQI request bit of the DCI being set to 1.

At step 103 , the UE jointly codes the CSIs of a number of downlink CCs and then transmits them to the BS.

The CSI acquisition unit 20 1 of the UE 200 acquires the resources for the non-periodic PUSCH transmission based on the received signaling. Then, depending on the agreement with the BS 100, the coding unit 202 of the UE 200 can coding, jointly or separately, the CSIs of a number of downlink CCs, and then add CRC or respective CRCs. Subsequently , it transmits them to the BS 100 via the transceiver unit 205. Herein, the CSIs for the number of downlink CCs can be the CSIs of all currently activated CCs including the PCC or can include only the CSIs of the SCCs newly activated in the last activation signaling. In the latter case, the CSI feedback based on non-periodic PUSCH for the SCCs or the PCC already activated before the arrival of the last activation signaling needs to be resumed after the completion of the CSI feedback for the newly activated SCCs.

At step 104, the BS performs downlink scheduling and the UE feeds back the CSIs periodically.

Upon reception of the CSIs fed back from the UE 200, the resource allocating and scheduling unit 102 of the BS 100 can perform downlink scheduling on the newly activated SCCs. In order for the resource allocating and scheduling unit 102 of the BS to keep track of the variation in the CSIs on the downlink CCs for the UE and to make correct scheduling decisions accordingly, the UE 200 needs to feed the CSIs of the downlink CCs back to the BS 100 periodically.

In the LTE R-8, the periodic CSI feedback is achieved with periodic PUCCH . In this case, the PUCCH resources used by the CSI feedback (including information on resource block indication, cyclic shift sequence indication, period, various time offsets and the like) is pre-configured by the resource allocating and scheduling unit 102 of the BS 100 to the UE 200 via RRC signaling by using the transceiver unit 104. However, in the LTE R- 10 where multiple downlink CCs are introduced, it is required to increase the PUCCH resources allocated to the UE, so as to periodically feed back the CSI of each of the downlink CCs on the uplink PCC. Since each downlink CC can be considered as one UE in the LTE R-8, N units of periodic PUCCH resources as defined in the LTE R-8 can be additionally allocated to a UE which has N downlink SCCs activated. In order to feed back the CSIs of different downlink CCs in a periodic cycling manner, for the additionally allocated N units of LTE R-8 PUCCH resources and the PUCCH resources of the corresponding original downlink PCC, the configuration of periods and time offsets should satisfy the requirement of cycling approach as shown in Fig. 3 or Fig. 4 (as an example, a UE has two downlink CCs) . It is to be noted that the cycling approach as shown in Fig. 3 and Fig. 4 is exemplary only. Any cycling approach is applicable as long as the CSIs of different CCs can be transmitted at different times and the BS can accurately track the CSIs of the downlink CCs. For different CCs, the resource blocks occupied by the PUCCH resources and the cyclic shift sequences can be different from each other.

As an example, a UE can have two downlink CCs, one of which is the PCC, as illustrated in Fig. 3. The PCC has a resource block A as its corresponding PUCCH resource, a cyclic shift sequence B and a period of 10ms in which the time offset of the feedback point is 1 ms. After newly activating a SCC, the BS allocates resources to the SCC. At this time, it is required to select PUCCH resources having the same period as the PUCCH resource corresponding to the PCC (i.e. , 10ms) but different time offsets (e.g. , 6ms as shown in Fig. 3) from a PUCCH resource pool reserved by the BS . The resource blocks and/ or the cyclic shift sequences corresponding to the selected PUCCH resources may be different from those of the PUCCH resources corresponding to the PCC. The additional PUCCH resources can be allocated in one of the following manners. They can be pre-configured to the UE by the BS via RRC signaling, just as the PUCCH resources corresponding to the downlink PCC are allocated. They can be embedded into the above-mentioned activation signaling and notified to the UE at activation of new SCC, or can be notified to the UE independently of the activation signaling. As an alternative, they can be notified to the UE via an additional Layer 1 , Layer 2 or Layer 3 signaling after the BS has confirmed a successful activation.

In addition to considering each downlink SCC as an independent UE for allocation of PUCCH resources as defined in the LTE R-8 , it is possible to reserve, via RRC signaling for example, a part of shared PUCCH resources exclusively for a UE with multiple downlink CCs activated in the LTE R- 10, so as to transmit the CSI feedback. Since there is generally a small number of UEs with multiple downlink CCs activated simultaneously, there will not be a large amount of PUCCH resource shared by these UEs, and most of the resource indication information has been configured to the UEs during resource reservation, the number of additional bits required for allocating the PUCCH resources is relatively small. As a result, the signaling overhead for transmitting these bits in connection with the above-mentioned RRC signaling, activation signaling and additional resource allocation signaling is also small.

An example for this is the Semi-Persistent Scheduling (SPS) resource allocation in the LTE R-8. As in the SPS resource allocation, when configuring SCCs for the UE (the BS needs to pre-configure associated parameters for the UE before activating a SCC, which is generally done via RRC signaling when the UE enters the system) , the BS semi-statically allocates to the UE a number of (e.g. , 4) PUCCH resources which are reserved by the BS exclusively for the UEs employing the CA technique. When activating the SCC, the BS can indicate which of the previously allocated 4 PUCCH resources is actually to be used for feeding back the CSI of the SCC, by using a 2-bit signaling. These two bits can be transmitted by means of activation signaling or any of the above signaling. The advantage of this resource allocation approach consists in that it is able to obtain statistical multiplexing gain of reserved resources.

In the LTE R- 10, for a UE with multiple downlink CCs activated, the above CSI feedback based on the periodic cycling may increase the density of CSI feedbacks in the time domain, thereby leading to an increased probability of collision between CSI feedback and HARQ feedback. In order to reduce the probability of such collision, periodic PUSCH can be used to transmit periodic CSI feedback. According to the CSI feedback approach based on periodic PUSCH, the resource allocating and scheduling unit 102 of the BS 100 allocates periodic PUSCH resources to each UE 200 with multiple downlink CCs activated. In each period, the coding unit 202 of the UE 200 codes, jointly or separately, the CSIs of all activated downlink CCs, add CRC or respective CRCs, and then transmit them to the BS 100 via PUSCH resources using the transceiver unit 205. As illustrated in Fig. 5, taking into account the fact that the downlink CCs with different center frequencies and/ or in different transmission modes may have different CSI feedback periods, the activated downlink CCs can be divided into several groups, based on frequency bands, transmission modes or other factors, with each group performing its periodic PUSCH transmission at a unique period. The resource allocation parameters, such as grouping scheme, period, time offset, resource block as well as modulation and coding scheme, can be configured by the resource allocating and scheduling unit 102 by embedding them into the above-mentioned activation signaling at activation of the downlink SCCs. Alternatively, such parameters can be configured/ reconfigured by using an additional Layer 1 , Layer 2 or Layer 3 signaling. In order to save the control overhead, it is required to assign the size of the periodic PUSCH resource (the number of the occupied resource blocks) according to the number of CCs already activated for the UE (if there is only one period) , or according to the number of CCs already activated in each group as described above (if there are more than one period) . The resource allocation can be configured by the resource allocating and scheduling unit 102 by embedding it into the above-mentioned activation signaling at activation of the downlink SCCs. Alternatively, it can be configured/ reconfigured by using an additional Layer 1 , Layer 2 or Layer 3 signaling. Furthermore, a resource allocation scheme similar to the above-mentioned scheme based on periodic PUCCH is also applicable to the resource allocation based on periodic PUSCH . That is, the resource allocation based on periodic PUSCH can be implemented by means of shared resource reservation plus additional signaling configuration.

At step 105, the BS deactivates the reception of multiple downlink SCCs by the UE, or the UE automatically deactivates the reception of downlink SCCs for which no scheduling is carried out for a long time.

When the downlink transmission of the UE 200 no longer requires a plurality of CCs, the control unit 101 of the BS 100 can instruct the transceiver unit 104 to deactivate the reception of some or all of the SCCs, except for the downlink PCC . Alternatively, by using the timer 203 , the control unit 204 of the UE 200 can instruct the transceiver unit 205 to automatically deactivate SCCs for which no scheduling is carried out for a long time . At deactivation of the SCCs, it is required to release the periodic PUCCH / PUSCH resources previously allocated to these SCCs for transmission of periodic CSI feedback, in order to improve transmission efficiency of the system. In general, the release of the resources can be achieved by default. That is, when the reception of a particular SCC is deactivated, its corresponding periodic PUCCH / PUSCH resources can be automatically reclaimed by the BS . However, for the periodic PUSCH CSI feedback as described above, when a part of feedback resources changes, some resource configuration parameters, such as grouping scheme, period, time offset, resource block as well as modulation and coding scheme, are required to be reconfigured. Then, when there is a deactivation signaling, the resource release signaling can be embedded into the deactivation signaling by the resource allocating and scheduling unit 102 for transmission, or can be transmitted by using an additional Layer 1 , Layer 2 or Layer 3 signaling. On the other hand, when there is no deactivation signaling, the additional Layer 1 , Layer 2 or Layer 3 signaling needs to be defined for reconfiguration of the feedback parameters.

The CSI feedback from the UE 100 to the BS 200 can be transmitted by a scheme in which transmission based on non-periodic PUSCH and transmission based on periodic PUCCH/ PUSCH are combined, or by a scheme based on non-periodic PUSCH transmission only. In the following, a part of the former scheme which is already described in the first embodiment is omitted and, for the latter scheme, the focus is placed on the CSI feedback based on non-periodic PUSCH scheduled at Layer 1 . That is, the resources for the CSI feedback based on non-periodic PUSCH are indicated by an uplink allocation defined in the LTE R-8 PDCCH DCI, in which the CQI request bit is set to 1 . If the CSI feedback is carried out only based on non-periodic PUSCH, the resources for periodic PUCCH are no longer used. If the CSI feedback is carried out based on non-periodic PUSCH, each time the BS needs the CSI feedback of a particular downlink CC, it can schedule one PUSCH for the UE which then codes, jointly or separately, the CSIs of the CCs for which the CSI feedbacks are required and collectively uploads them to the BS over the PUSCH resource. As for the CSIs of which CCs need to be transmitted in this scheduling, the details will be given in the embodiment below.

The Second Embodiment

In this embodiment, it is scheduled such that the PDCCH for the CSI feedback transmission based on non-periodic PUSCH can be transmitted in all activated downlink CCs (the set of downlink PCC and activated downlink SCCs) . Similarly, the uplink CSI feedback based on non-periodic PUSCH can be transmitted over the uplink PCC.

The advantage of allowing the PDCCH for the CSI feedback transmission based on non-periodic PUSCH to be scheduled such that it can be transmitted in all the activated downlink CCs is to make the transmission of a scheduling request more flexible. When a particular downlink CC is just activated, or when the BS needs to acquire the detailed CSI of the downlink CC for some reason, the resource allocating and scheduling unit 102 of the BS 100 can transmit an uplink allocation in the control area of the downlink CC through the transceiver unit 104, with the CQI request bit being set to 1 . If the downlink CC does not need a CIF, the uplink allocation will instruct the UE to transmit the CSI of the downlink CC over the uplink PCC according to the uplink allocation. If the downlink CC needs a CIF, the CIF can be set to 0 and then the uplink allocation can again instruct the UE to transmit the CSI of the downlink CC over the uplink PCC according to the uplink allocation. If the downlink CC (Downlink CC 1 ) is not contained in the CCs within the detection control (PDCCH monitoring) area of the UE, the above-mentioned uplink allocation with the CQI request bit set to 1 is required to be placed into the control area of another downlink CC (Downlink CC2) which uses a CIF (such that the UE in the control area of the CC2 can perform detection) and has its CIF set to be the CIF value corresponding to the CC 1 . In this way, the uplink allocation will instruct the UE to transmit the CSI of the downlink CC 1 over the uplink PCC according to the uplink allocation.

As described above, each uplink scheduling with its CQI request bit set to 1 can be scheduled to transmit the non-periodic CSI feedback for only one downlink CC. In order to enable an uplink scheduling to schedule the non-periodic CSI feedbacks for a plurality of downlink CCs, the CIF and/ or some data fields in the above uplink allocation need to be redefined to indicate a group of downlink CCs currently requiring to transmit non-periodic CSI feedbacks. As shown in Fig. 6, for example, a UE activates 5 CCs including the PCC in the downlink. The CIF is currently defined to have a fixed length of 3 bits and thus have 8 statuses. Other than the 5 statuses for indicating each downlink CC, there are 3 statuses for indicating 3 groups as shown in Fig. 6, respectively. Group 1 and Group 2 each correspond to a frequency band in which a number of downlink CCs generally have similar requirements on CSI transmission. Group 3 corresponds to all the downlink CCs. As such, after the transceiver unit 205 of the UE detects an uplink scheduling with its CQI request bit set to 1 , it is determined, based on the CIF status of the uplink scheduling, to transmit the non-periodic feedback of the downlink CC, or the group of downlink CCs, corresponding to the status over the uplink PCC. While the grouping based on frequency band is illustrated by way of example, any other factors, such as transmission mode, can be used as the principle of grouping.

The Third Embodiment

In this embodiment, it is scheduled such that the PDCCH for the CSI feedback transmission based on non-periodic PUSCH can be transmitted in all activated downlink CCs. Further, the uplink CSI feedback based on non-periodic PUSCH can be transmitted in all uplink CCs.

The advantage of allowing the uplink CSI feedback based on non-periodic PUSCH to be transmitted in all uplink CCs consists in that the collision between the CSI feedback and the HARQ feedback can be avoided by scheduling the CSI feedback to be transmitted in uplink SCCs. Since the PUCCH HARQ feedback is required to be transmitted in the uplink PCC, as described in the background section, there is a relatively high probability of such collision if the CSI feedback is also limited to be transmitted in the uplink PCC . In this embodiment, the CIF in the uplink allocation is used to indicate which uplink CC is associated with the uplink allocation. Thus, it is impossible to use the CIF to indicate which downlink CC, or group of downlink CCs, is associated with the non-periodic CSI feedback corresponding to the uplink allocation, as in the second embodiment.

However, there are two exceptions. First, when the non-periodic CSI feedback for a particular downlink CC is limited to be transmitted in an uplink CC paired (according to the LTE R-8 rule or any other predetermined rule) with the downlink CC, the CIF in the uplink allocation is only required to indicate which uplink CC is associated with the uplink allocation. In this case, the non-periodic CSI feedback corresponding to the uplink allocation is associated with the downlink CC paired with the uplink CC . Second, when the uplink allocation for a particular downlink CC is limited to be associated with the uplink CC paired (according to the LTE R-8 rule or any other predetermined rule) with the downlink CC, the CIF in the uplink allocation can be used to indicate which downlink CC is associated with the non-periodic CSI feedback corresponding to the uplink allocation.

Apart from the above exceptions, some data fields in the uplink allocation are required to be redefined, so as to flexibly indicate which downlink CC, or group of downlink CCs, is associated with the non-periodic CSI feedback corresponding to the uplink allocation. As an example, it can be specified that only part of statuses of the Modulation and Coding Scheme and Redundancy Version field in uplink allocation control information can be used to represent the modulation, coding scheme and redundancy version actually used by the non-periodic CSI feedback, while the remaining part of statuses are used to indicate which downlink CC, or group of downlink CCs, is associated with the non-periodic CSI feedback corresponding to the uplink allocation. There are other data fields to be redefined, such as the Cyclic shift for DM RS field. If there are too many constraints on such redefinition, additional bits can be added for indicating the above information. Further, the following approaches can be applied if the size of the uplink allocation control information cannot be changed.

As shown in Fig. 7, the DCI in the PDCCH of the LTE R- 10 includes uplink allocation control information which consists of three parts, uplink allocation control information in LTE R-8 , CIF (whose presence depends on whether the associated downlink CC uses an inter-carrier scheduling) and Cyclic Redundancy Check (CRC) . In the LTE R-8, the above CRC is scrambled with the ID, such as Cell Radio Network Temporary ID (C-RNTI) , of the UE. According to the present invention, a number (e.g. , X) of masking sequences can be further added to the scrambling sequence (such as C-RNTI) for the CRC in the LTE R- 10. The resource allocating and scheduling unit 102 of the BS 100 can select one out of the X masking sequences stored in the memory unit 103 as desired. The selected masking sequence is XOR-ed with the original scrambling sequence and then used for scrambling the CRC. The transceiver unit 205 of the UE 200 can detect the masking sequence selected by the BS during a blind PDCCH detection process. In this way, additional log2 (X) bits of information can be obtained. Of course, this effect comes at the expense of a decreased number of allocable UE IDs and an increased probability of collision between UE IDs. However, it can still be considered as an effective way of reducing control overhead if there is a moderate number of masking sequences to be used. As an example, if there are 4 masking sequences to be used, equivalently, an uplink allocation can have 2 additional bits which, along with the fixed 3 bits of the CIF, can provide 32 (2⁵) statuses for indicating the above information, including information on which uplink CC is associated with the uplink allocation and information on which downlink CC, or group of downlink CCs, is associated with the non-periodic CSI feedback corresponding to the uplink allocation. In the above description, the grouping of CCs in the second embodiment can be applied. The redefinition of data fields in this embodiment is also applicable to other embodiments.

The Fourth Embodiment

In the LTE R- 10 system, in order to keep consistence between the inter-carrier scheduling and the intra-carrier scheduling in terms of probability of erroneous detection for Control Format Indicator (CFI) on Physical Control Format Indicator CHannel (PCFICH) , there is a need for a method of reducing the probability of erroneous detection for CFI in the inter-carrier scheduling. "Views on Solution to PCFICH Detection Error, R l -094237, RAN I #58bis, NTT DOCOMO, October, 2009" presents a method for implicitly indicating CFI based on CRC mask of PDCCH in the inter-carrier scheduling mode. Particularly, a mask associated with the control format of the carrier carrying the PDSCH is added to the CRC of the DCI format corresponding to the PDCCH used for inter-carrier scheduling, as illustrated in Fig. 8. Thus, the transceiver unit 205 of the UE 200 can obtain the control format information of the carrier carrying the PDSCH in an implicit way by checking different CRC masks at blind PDCCH detection. A problem with this method consists in that, when compared with a similar method in LTE R-8 (uplink antenna selection, in which 2 CRC masks are required) , the allocable UE IDs are reduced since more (3) CRC masks are to be introduced. As a result, there are more CRC checks than LTE R-8 for each UE, which may leads to an increased probability of PDCCH false alarm.

In this regard, the standardization of LTE R- 10 tends to solve this problem by one of two approaches including RRC signaling indication and DCI signaling indication based on jointly coded CFI and CIF. The latter is described in PCFICH for "Cross-Carrier Assignment, R l - 102288, RAN I #60bis, NTT DOCOMO, 2010". However, the two approaches have their respective defects. The former approach has limitation in scheduling and may cause waste of resources in practice, while the latter is not applicable to the situation of a large number of activated downlink CCs.

As shown in Table 1 and Table 2 , only the approach of DCI signaling indication based on jointly coded CFI and CIF is employed. Herein, CC0 does not indicate CFI information since it indicates the current CC, i.e. , the inter-carrier scheduling CC. It can be seen that, when the number of activated CCs is larger than 3 , not all combinations of CFI and CIF can be reflected in the CIF by means of joint coding due to the limitation on the number of bits of CIF (fixed 3 bits ). A problem with this consists in that the CFI value of a CC which cannot be indicated in the CIF can only use a fixed value or can only be obtained by means of RRC signaling configuration.

Table 1 - Interference Coordination Indication Coding Table

Number of Activated CCs

CIF

2 3 4 5

000 CCO, - CCO, - CCO, - CCO, -

001 CCl, CFI=1 CCl, CFI=1 CCl, CFI=1 CCl, CFI=1

010 CCl, CFI=2 CCl, CFI=2 CCl, CFI=2 CCl, CFI=2

011 CCl, CFI=3 CCl, CFI=3 CCl, CFI=3 CCl, CFI=3

100 - CC2, CFI=1 CC2, CFI=1 CC2, CFI=3

101 - CC2, CFI=2 CC2, CFI=2 -

110 - CC2, CFI=3 CC2, CFI=3 CC4, CFI = N

111 - - CC3, CFI=N CC3, CFI=N

Table 2 - Another Joint Coding Approach of CIF and CFI

In this embodiment, a simple method of CFI indication for inter-carrier scheduling is provided by a combination of DCI signaling indication based on jointly coded CFI and CIF and implicit indication of CRC masks, which can overcome the defects of the conventional DCI signaling indication based on jointly coded CFI and CIF.

The resource allocating and scheduling unit 102 of the BS 100 can allocate a number (X) of CRC masking sequences to a UE which supports simultaneous activation of multiple downlink CCs. When scheduling the downlink allocation DCI in an inter-carrier manner, the BS can select a CIF value and a CRC masking sequence based on the status of jointly coded CIF and CFI to be transmitted. Then, the selected CIF value can be added to the downlink allocation and the selected CRC masking sequence can be used to scramble the CRC corresponding to the DCI, which CRC is in turn used to scramble the ID of the UE. The transceiver unit 205 of the UE 200 with a plurality of activated downlink CCs can detect whether these CRC masks are present or not during its blind detection process, in addition to detecting the ID of a UE. When the UE detects a PDCCH based on a combination of the ID of a UE and a CRC masking sequence as mentioned above, the CIF in the DCI corresponding to the PDCCH is extracted and then used, along with the detected CRC masking sequence, to determine the status of the jointly coded CIF and CFI to be transmitted by the BS. Equivalently, the CRC masking sequence can carry log2(X) bits of information. These bits can be used, in connection with the fixed 3 bits of CIF, to solve the above-mentioned problem of not all combinations of CFI and CIF being reflected in the CIF by means of joint coding due to insufficient CIF bits.

Taking the two CRC masks in Table 3 as an example, the transceiver unit 205 of the UE 200 can equivalently obtain 1 bit information in addition to the DCI during its blind detection. Along with the 3-bit information of CIF, this 1 bit information can provide 16 statuses, which are sufficient for satisfying the requirement of joint coding of CIF and CFI . Next, a method according to this embodiment will be further explained with reference to a simple joint coding approach shown in Table 4. For example, the BS has now activated 4 CCs including the PCC, and needs to transmit a DCI over CCO to indicate a downlink allocation for CC2. If the CFI of CC2 is currently 2 , the joint coding status of CIF and CFI can be determined as 101 / 1 by looking up Table 4. That is, the CIF has a value of 101 , and the CRC masking sequence 1 is to be used. In this case, the BS writes 101 into the CIF field of the downlink allocation and calculates the CRC for the entire DCI. The calculated CRC is then XOR-ed with the CRC masking sequence 1 , arid further XOR-ed with the ID of the UE corresponding to the DCI, and finally placed onto the PDCCH for transmission. The UE blindly detects the PDCCH in the CCO using various combinations of its device ID and possible CRC masking sequences. In the case of a successful detection, the UE can detect the PDCCH and extract the CIF value from the DCI in the PDCCH. From the extracted CIF value and the CRC masking sequence by which the PDCCH is detected, it can be determined with reference to Table 4 that the downlink allocation corresponds to the CC2 and the CFI value of the CC2 is 2.

Of course, Table 4 can be further optimized. For example, taking into account that the UE will generally first detect masking sequence 1 during its blind detection, some joint codes having higher possibility to occur in the joint status of CIF and CFI can be arranged in the first half of Table 4 where the masking sequence 1 is to be used. The configuration /reconfiguration of Table 4 can be carried out by means of RRC signaling. Table 5 gives another possible joint coding approach.

Table 3 - Masking Sequences in Use

Sequence Number Masking Sequence

1 <0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0>

2 <0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1>

Table 4 - CFI Indication Approach for Inter-Carrier Scheduling by Combination of DCI Signaling Indication

Based on Jointly Coded CFI and CIF and Implicit Indication of CRC Masks

CIF/Masking Number of Activated CCs

Sequence

2 3 4 5

000/ 1 CCO, - CCO, - CCO, - CCO, -

001/1 CCl, CFI=1 CCl, CFI=1 CCl, CFI=1 CCl, CFI=1

010/1 CCl, CFI=2 CCl, CFI=2 CCl, CFI=2 CCl, CFI=2

011/1 CCl, CFI=3 CCl, CFI=3 CCl, CFI=3 CCl, CFI=3

100/1 - CC2, CFI=1 CC2, CFI=1 CC2, CFI=1

101/1 - CC2, CFI = 2 CC2, CFI=2 CC2, CFI=2

110/1 - CC2, CFI=3 CC2, CFI=3 CC2, CFI=3

111/1 - - CC3, CFI=1 CC3, CFI=1

-Borderline-

000/2 - - CC3, CFI=2 CC3, CFI=2

001/2 - - CC3, CFI=3 CC3, CFI=3

010/2 - - - CC4, CFI=1

011/2 - - - CC4, CFI=2

100/2 - - - CC4, CFI=3

101/2 - - - -

110/2 - - - -

111/2 - - - -

Table 5 - Another Possible Approach for Joint Coding

Similar to the joint coding approaches as shown in Tables 4 and 5, for each inter-carrier scheduled CC, mapping between the CC serial numbers and the actual physical CCs may change. Such a change can be made by means of RRC signaling.

Further, if the joint coding approach is designed as illustrated in Table 6, the mapping between the CC serial numbers and the actual physical CCs can remain consistent for different inter-carrier scheduled CCs, without any additional configuration. Another advantage of Table 6 is that different UEs may have the same mapping between the CC serial numbers and the actual physical CCs, without any additional configuration.

Table 6 - A Further Possible Approach for Joint Coding

The Fifth Embodiment

In the uplink PCC, if HARQ feedbacks corresponding to a plurality of downlink CCs are transmitted simultaneously with CSI feedbacks based on periodic or non-periodic PUSCH , it is required to transmit the HARQ feedbacks over the PUSCH due to limited uplink peak-to-average ratio.

Herein, the HARQ feedbacks corresponding to a plurality of downlink CCs refer to ACK/ NACK which occupies a plurality of bits and can be transmitted over the PUCCH when no CSI feedback is transmitted at the same time. An example is that the HARQ feedbacks can be transmitted in PUCCH Format 2 as defined in LTE R-8. In the case of a small number (for example, 2) of activated CCs, the number of corresponding HARQ bits is relatively small (for example, 5) , and they can be transmitted in one PUCCH Format 2. On the other hand, in the case of a larger number (for example, more than 3) of activated CCs, the number of corresponding HARQ bits is relatively large (for example, 10) , and they can be transmitted in two PUCCH

Format 2 corresponding to resources allocated in one Physical Resource Block (PRB) .

In this embodiment, when HARQ feedback and CSI feedback are transmitted simultaneously, the HARQ feedback is transmitted over the PUSCH instead of PUCCH .

When HARQ feedback and CSI feedback are transmitted together over the PUSCH, they can be coded jointly or separately. The coding scheme can be implemented with convolutional code or block code (e . g. , Reed Muller code in LTE R-8) , depending on the amount of feedback. The coded bits can be subjected to symbol mapping, and then, as shown in Fig. 9 , placed into the PUSCH resource in the same manner as defined in LTE R-8. For details of the mapping scheme, reference can be made to those in LTE R-8 as introduced in "BACKGROUND ART" . Locations for CSI and HARQ feedbacks shown in Fig. 9 may change depending on different design requirements. However, it is necessary to ensure that the respective symbols corresponding to the CSI feedback and the HARQ feedback do not overlap with each other, in order to avoid any loss due to dropping or puncturing.

Parameter configuration, signaling and the like in the above embodiments are UE specific unless indicated otherwise.

A number of examples have been illustrated for the respective steps in the above description. While the inventor has tried to list the examples in association with each other, it does not imply that it is necessary for the listed examples to have such correspondence as suggested by reference numerals. A number of solutions can be achieved by selecting examples having no correspondence in terms of reference numerals in different steps, as long as the conditions underlying the selected examples do not conflict with each other. Such solutions are encompassed by the scope of the present invention.

It is to be noted that, in the above description, the solutions of the present invention has been illustrated by way of example only. However, it does not mean that the present invention is limited to the above steps and element structures. Rather, it is possible to change and modify the steps and element structures depending on actual requirements. Thus, some of these steps and elements are not essential to the implementation of the general concept of the present invention. Therefore, the essential technical features of the present invention are not limited to the above particular examples, but to the minimum requirement for implementing the general concept of the present invention only.

The present invention has been described above with reference to the preferred embodiments thereof. It should be understood that various modifications, alternations and additions can be made by those who skilled in the art without departing from the spirits and scope of the present invention. Therefore, the scope of the present invention is not limited to the above particular embodiments but only defined by the claims as attached.

Claims

Claim 1

A method for transmitting physical uplink control information, comprising the following steps of:

-activating, by a Base Station (BS) , reception of one or more downlink Secondary Component Carriers (SCCs) by a User Equipment (UE) ;

-notifying, by the BS, the UE of resources based on non-periodic Physical Uplink Shared CHannel (PUSCH) for transmission of uplink control information;

-jointly coding, by the UE, Channel State Indicators (CSIs) for downlink Component Carriers (CCs) including a downlink SCC and/ or a downlink Primary Component Carrier (PCC) and transmitting the coded CSIs to the BS by using the resources;

-performing, by the BS, a downlink scheduling based on the CSIs; and

-feeding, by the UE, CSIs for the downlink CCs back to the BS periodically, such that the BS can track variation in the CSIs for the downlink CCs.

Claim 2

The method for transmitting physical uplink control information according to claim 1 , further comprising a step of:

-scheduling, by the BS, additional resources based on non-periodic PUSCH to the UE for transmitting CSI feedback, if necessary.

Claim 3

The method for transmitting physical uplink control information according to claim 1 , further comprising steps of:

-deactivating, by the BS, the reception of the downlink SCCs by the UE; or

-automatically deactivating, by the UE, the reception of a downlink CC for which no scheduling is carried out for a predetermined period.

Claim 4

The method for transmitting physical uplink control information according to claim 1 , wherein

the step of the BS activating the reception of one or more downlink SCCs by the UE is performed by means of Layer 1 and/ or Layer 2 and/ or Layer 3 signaling.

Claim 5

the step of the BS notifying the UE of the resources for transmission of uplink control information is performed by means of activation signaling or Layer 1 and/ or Layer 2 and/ or Layer 3 signaling independent of the activation signaling. Claim 6

the CSIs for the downlink CCs including the downlink SCCs and/ or the downlink PCC are the CSIs for the downlink CCs including the downlink PCC and/ or all currently activated downlink SCCs, or the CSIs for the downlink CCs including only the downlink SCCs newly activated in the last activation signaling.

Claim 7

The method for transmitting physical uplink control information according to claim 1 , wherein the step of the UE feeding the CSIs for the downlink CCs back to the BS periodically comprises:

-feeding, by the UE, back the CSI for each downlink SCC periodically, wherein the resources for feeding back the CSI for each downlink SCC are periodic Physical Uplink Control

CHannel (PUCCH) resources which are additionally configured by the BS for the UE and defined as the same as in

LTE R-8.

Claim 8 The method for transmitting physical uplink control information according to claim 7, wherein the resources for feeding back the CSI for each downlink SCC are notified by means of activation signaling or Layer 1 and/ or Layer 2 and/ or Layer 3 signaling independent of the activation signaling.

Claim 9

-feeding, by the UE, back the CSIs for all downlink CCs periodically by using periodic PUSCH resources which are additionally configured by the BS for the UE.

Claim 10

The method for transmitting physical uplink control information according to claim 9, wherein

the activated downlink SCCs are divided into a number of groups each performing periodic PUSCH transmission at a unique period.

Claim 1 1

The method for transmitting physical uplink control information according to any one of claims 1 - 10, wherein the PDCCH for transmission of CSI feedback based on non-periodic PUSCH is scheduled to be transmitted in all activated downlink CCs, and

the CSI feedback based on non-periodic PUSCH is scheduled to be transmitted in the uplink PCC.

Claim 12

The method for transmitting physical uplink control information according to claim 1 1 , wherein

a Carrier Indicator Field (CIF) in the PDCCH is used to indicate for which downlink CC the CSI feedback is required to be transmitted in the uplink PCC.

Claim 13

The method for transmitting physical uplink control information according to claim 1 1 or 12 , wherein

the CIF and/ or some other data fields in the PDCCH are defined to indicate a group of downlink CCs for which the CSI feedbacks are currently required to be transmitted based on non-periodic PUSCH.

Claim 14

The method for transmitting physical uplink control information according to any one of claims 1 - 10, wherein

the PDCCH for transmission of CSI feedback based on non-periodic PUSCH is scheduled to be transmitted in all the activated downlink CCs, and

an uplink CSI feedback based on non-periodic PUSCH is scheduled to be transmitted in all uplink CCs.

Claim 15

The method for transmitting physical uplink control information according to claim 14, wherein

Claim 16

The method for transmitting physical uplink control information according to any one of claims 1 - 15 , wherein

the physical uplink control information comprises Channel Quality Indicator (CQI) , Precoding Matrix Indicator (PMI) and Rank Indicator (RI) .

Claim 17

The method for transmitting physical uplink control information according to any one of claims 1 , 7 and 8 , wherein the resources for periodic CSI feedback comprises resource block indication, cyclic shift sequence indication, period and time offset.

Claim 18

A Base Station (BS) comprising:

-a transceiver unit for activating reception of one or more downlink Secondary Component Carriers (SCCs) by a User Equipment (UE) and notifying the UE of resources for non-periodic transmission of uplink control information; and -a resource allocating and scheduling unit for performing downlink scheduling based on Channel State Indicators (CSIs) for downlink channels fed back from the UE,

wherein the transceiver unit is configured for receiving CSIs for downlink Component Carriers (CCs) including a downlink SCC and/ or a downlink Primary Component Carrier (PCC) as transmitted from the UE by using the resources,

the resource allocating and scheduling unit is configured for performing the downlink scheduling based on the CSIs, and the transceiver unit is further configured for receiving CSIs for the downlink CCs fed back from the UE periodically, such that the BS can track variation in the CSIs for the downlink CCs.

Claim 19

The BS according to claim 18, wherein

the transceiver unit is configured to deactivate the reception of the downlink SCCs by the UE. Claim 20

The BS according to claim 18 , wherein

activating the reception of one or more downlink SCCs by the UE is performed by means of Layer 1 and/ or Layer 2 and/ or Layer 3 signaling.

Claim 2 1

The BS according to claim 18, wherein

notifying the UE of the resources for transmission of uplink control information is performed by means of activation signaling or Layer 1 and / or Layer 2 and / or Layer 3 signaling independent of the activation signaling.

Claim 22

A User Equipment (UE) comprising:

-a transceiver unit for receiving a notification of activation to receive one or more downlink Secondary Component Carriers (SCCs) and a notification of resources for non-periodic transmission of uplink control information by the UE;

-a Channel State Indicator (CSI) acquisition unit for acquiring CSIs for downlink Component Carriers (CCs) including a downlink SCC and/ or a downlink Primary Component Carrier (PCC) ; and -a coding unit for jointly coding the CSIs for the downlink CCs including the downlink SCC and/ or the downlink PCC, wherein the transceiver unit is configured for transmitting the jointly coded CSIs to a Base Station (BS) and then feeding the CSIs for the downlink CCs back to the BS periodically, such that the BS can track variation in the CSIs for the downlink CCs.

Claim 23

The UE according to claim 22, wherein

the UE is configured to automatically deactivate the reception of a downlink CC for which no scheduling is carried out for a predetermined period.

Claim 24

The UE according to claim 23, wherein

the UE is configured to feed back the CSI for each downlink SCC periodically, wherein the resources for feeding back the CSI for each downlink SCC are periodic Physical Uplink Control CHannel (PUCCH) resources which are additionally configured by the BS for the UE and defined as the same as in LTE R-8.

Claim 25

The UE according to claim 22 , wherein the UE is configured to feed back the CSIs for all downlink CCs periodically by using periodic PUSCH resources which are additionally configured by the BS for the UE.