Apparatus and method for resource allocation information transmission in mobile communication system

An apparatus and method for resource allocation information transmission is provided. The method includes determining a search space for use in a second frequency band using resource allocation information of a first process detected in a first frequency band, detecting resource allocation information using the search space in the second frequency band, and when failing to decode received data according to the resource allocation information detected in the second frequency band, re-detecting resource allocation information of the first process in the second frequency band in a first time interval using the search space without detecting the resource allocation information of the first process in the first frequency band.

PRIORITY

The present application claims the benefit under 35 U.S.C. §119(a) of a Korean patent application filed in the Korean Intellectual Property Office on Jun. 10, 2009 and assigned Serial No. 10-2009-0051588, the entire disclosure of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus and a method for transmitting resource allocation information. More particularly, the present invention relates to a carrier aggregation system in which a user equipment can simultaneously transmit and receive data using a plurality Component Carriers (CCs).

2. Description of the Related Art

Recently, research has been conducted on methods for using carrier aggregation that allow one user equipment to simultaneously transmit and receive data using a plurality of carriers in a mobile communication system. Herein, each carrier constituting the plurality of carriers usable by the user equipment is referred to as a Component Carrier (CC). A CC is also called a fundamental unit of an operable frequency band of the system, that is, a Frequency Assignment (FA). In a carrier aggregation system, the user equipment, which transmits and receives data using the multiple carriers at the same time, needs to detect resource allocation information of the carriers together.

However, methods for transmitting and encoding the resource allocation information of the carriers or the CCs are not yet specified. In this regard, there is a requirement for a concrete method for effectively transmitting the resource allocation information of the CC.

Therefore, a need exists for an apparatus and method for transmitting resource allocation information in a mobile communication system.

SUMMARY OF THE INVENTION

An aspect of the present invention is to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide an apparatus and a method for transmitting resource allocation information in a mobile communication system.

Another aspect of the present invention is to provide an apparatus and a method for transmitting resource allocation information of low blind decoding complexity in a mobile communication system.

Yet another aspect of the present invention is to provide an apparatus and a method for allowing Hybrid Automatic Repeat reQuest (HARQ) retransmission of a non-anchor CC alone and simultaneously maintaining low blind decoding complexity.

In accordance with an aspect of the present invention, a method for receiving resource allocation information in a mobile communication system is provided. The method includes determining a search space for use in a second frequency band using resource allocation information of a first process detected in a first frequency band, detecting resource allocation information using the search space in the second frequency band, and when failing to decode received data according to the resource allocation information detected in the second frequency band, re-detecting resource allocation information of the first process in the second frequency in a first time interval using the search space without detecting the resource allocation information of the first process in the first frequency band.

In accordance with another aspect of the present invention, an apparatus for receiving resource allocation information in a mobile communication system is provided. The apparatus includes a controller for determining a search space for use in a second frequency band using resource allocation information of a first process detected in a first frequency band, for detecting resource allocation information using the search space in the second frequency band, and, when failing to decode received data according to the resource allocation information detected in the second frequency band, for re-detecting resource allocation information of the first process in the second frequency in a first time interval using the search space without detecting the resource allocation information of the first process in the first frequency band.

In accordance with yet another aspect of the present invention, a method for transmitting resource allocation information in a mobile communication system is provided. The method includes, when generating resource allocation information for retransmission, generating the resource allocation information such that a resource for the retransmission is not included in a first frequency band and is included only in a second frequency band, determining a transmission resource using the resource allocation information, and transmitting the resource allocation information to a receiver over the transmission resource.

In accordance with still another aspect of the present invention, an apparatus for transmitting resource allocation information in a mobile communication system is provided. The apparatus includes a controller for, when generating resource allocation information for retransmission, generating the resource allocation information such that a resource for the retransmission is not included in a first frequency band and is included only in a second frequency band, and for determining a transmission resource using the resource allocation information, and a transmitter for transmitting the resource allocation information to a receiver over the transmission resource.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments of the present invention provide an apparatus and a method for transmitting resource allocation information in a mobile communication system.

In a carrier aggregation system, a User Equipment (UE) simultaneously transmits and receives data using a plurality of Component Carriers (CCs) and thus needs to detect resource allocation information of the CCs together.

There are various resource allocation information transmitting methods depending on whether the resource allocation information of the CCs are encoded together or per CC and which CC carries the encoded resource allocation information.

The carrier aggregation system is newly adopted by the Institute of Electrical and Electronics Engineers (IEEE) 802.16m and the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE)-Advanced and its standardization is under way. The carrier aggregation system is also called a multi-carrier system, a multi-Frequency Assignment (FA) system, and a frequency overlay system. Herein, the bandwidth of the CC, for example, can be determined as the bandwidth of the IEEE 802.16 and the LTE system.

FIG. 1illustrates a carrier aggregation system according to an exemplary embodiment of the present invention.

Referring toFIG. 1, an eNode B100transmits and receives data using a plurality of CCs. UEs110,120and130can differently set the number and the range of the CCs to transmit and receive, based on their capability.

When carrier aggregation is employed in the mobile communication system, it is necessary to acquire resource allocation information of each CC. Blind decoding is used by the UE to obtain its corresponding resource allocation information in the allocated resource, that is, in the CC. Rather than directly obtaining the resource allocation information from separate control information, blind decoding allows only a particular UE to succeed in decoding according to a preset rule. In general, blind decoding does not include a UE Identifier (ID) in the resource allocation information. The resource allocation information of each UE is transmitted such that it is decoded only by the UE using its ID to decode the information. For instance, the eNode B transmits the resource allocation information by scrambling or masking the UE ID with all or part of the resource allocation information including a Cyclic Redundancy Check (CRC), and the UE can obtain the resource allocation information by descrambling or demasking it using its own ID. Advantageously, blind decoding assists in maintaining a small message size of the resource allocation information by not explicitly sending the UE ID. Blind decoding is expected to be used in both the IEEE 802.16m system and the LTE-Advanced system.

According to an exemplary embodiment of the present invention, a method for encoding the resource allocation information of the CC per CC and transmitting the resource allocation information over different physical channels is provided. For example, in the LTE system, the physical channel carrying the resource allocation information can be referred to as a Physical Downlink Control CHannel (PDCCH). The PDCCH is separately given per CC and the resource allocation information of each CC can be transmitted over each PDCCH. However, using carrier aggregation, it is necessary to obtain the resource allocation information of each CC by detecting each CC. As a result, when the resource allocation information is blind-decoded and transmitted, the complexity is increased.

Alternatively, a concept of an anchor CC is introduced in order to lower the blind decoding complexity. Herein, the UE can select its anchor CC from the plurality of CCs, and preferentially detect the resource allocation information in the anchor CC. In an exemplary implementation, the UE searches the resource allocation information in its selected anchor CC, and searches the resource allocation information of non-anchor CCs only when detecting the resource allocation information.

According to an exemplary embodiment of the present invention, a method for setting the anchor CC and non-anchor CC setting provided. The eNode B selects one or more CCs, from the plurality of the operating CCs, as the CCs for use by the UE. The CCs used by the UEs can differ from each other. For example, when the eNode B operates five CCs {CC1, CC2, CC3, CC4, CC5}, the CCs for use by the first UE can be set to {CC1, CC2, CC3} and the CCs for use by the second UE can be set to {CC3, CC4, CC5}.

The eNode B selects one or more CCs from the CCs for use by the UE as the anchor CC of the corresponding UE. In the above-stated example, the anchor CC of the first UE can be set to CC1 and the anchor CC of the second UE can be set to CC3.

The other CCs excluding the anchor CC among the CCs used by the UE become the non-anchor CCs. In the above example, the non-anchor CCs of the first UE are {CC2, CC3}, and the non-anchor CCs of the second UE are {CC4, CC5}.

The anchor and non-anchor CC setting can be carried out during an initial access of the UE, a handover, an eNode B request, a UE request, a radio resource configuration, and the like.

Regarding use of the anchor CC, provided that the UE searches the resource allocation information in the anchor CC and searches the resource allocation information of the other CCs (the non-anchor CCs) only when detecting the resource allocation information in the anchor CC, a method for detecting the resource allocation information when there is no resource allocation information in the anchor CC and the resource allocation information is transmitted only in the non-anchor CC, is required. Furthermore, to search the resource allocation information of the other CCs only when the resource allocation information is detected in the anchor CC as mentioned above, it may be impossible to retransmit Hybrid Auto Repeat reQuest (HARQ) in the non-anchor CC alone. For example, when a transmitter performs an initial HARQ transmission using the anchor CC and the non-anchor CC wherein the transmission in the anchor CC succeeds and the transmission in the non-anchor CC fails, the HARQ retransmission using only the non-anchor CC can take place but may require a complex operation and thus render it infeasible.

Hence, to lower the complexity in the blind decoding as discussed earlier, consideration is given to an exemplary method is provided for limiting a search condition and a search range of the resource allocation information of the non-anchor CC. This method restricts the PDCCH search range in the non-anchor CC according to resource size and location corresponding to the PDCCH detected in the anchor CC. When the LTE system or the IEEE 802.16 system adopts this method, the number of PDCCH decoding times in the anchor CC is limited to 44 and the number of PDCCH decoding times in the non-anchor CC is limited to n (1≦n≦44), thus lowering the overall complexity in the blind decoding.

FIG. 2illustrates a resource allocation transmission process using a dummy PDCCH according to an exemplary embodiment of the present invention.

Referring toFIG. 2, only upon detecting the dummy PDCCH in the anchor CC can the UE obtain the corresponding resource allocation information in the non-anchor CC in step210. This implies that the UE obtains the resource allocation information in the non-anchor CC by adding the dummy PDCCH to the anchor CC.

To perform HARQ retransmission only using the non-anchor CC, an exemplary method in which the eNode B does not include dummy resource allocation information in the anchor CC is explained. In the following description, PDCCH detection and resource allocation information detection are regarded as the same expression. In an exemplary implementation, the eNode B can be the transmitter and the UE can be the receiver. However, depending on the object that transmits data, the UE may be the transmitter and the eNode B can be the receiver.

For the UE to search the resource allocation information of the non-anchor CC, an exemplary time interval setting method for searching the resource allocation information of the non-anchor CC is described.

When detecting the resource allocation information in the anchor CC, the UE searches the resource allocation information in subframes of the non-anchor CC of the same time. Also, if the resource allocation information is not detected in the anchor CC, the UE searches the resource allocation information in the subframes of the non-anchor CC predicted to contain the resource allocation information for the HARQ retransmission.

As for a synchronous HARQ process, the predicted time interval of the resource allocation information for the HARQ retransmission becomes one subframe defined by a HARQ retransmission period. Thus, the UE searches the resource allocation information of the non-anchor CC in the one defined subframe.

FIG. 3illustrates a resource allocation information searching process using synchronous HARQ in the downlink according to an exemplary embodiment of the present invention.

Referring toFIG. 3, it is assumed that the synchronous HARQ is set to conduct the HARQ retransmission after seven subframes. When the UE detects the PDCCH in the anchor CC, that is, when the UE detects the resource allocation information but fails to detect the PDCCH310in the non-anchor CC, the UE detects the PDCCH320in the eighth subframe after the seven subframes in the non-anchor CC.

FIG. 4illustrates a time interval setting method for searching the resource allocation information using asynchronous HARQ in the downlink according to an exemplary embodiment of the present invention.

In an asynchronous HARQ process, when HARQ retransmission is necessary, a subframe time interval for searching the resource allocation information can be determined as follows.

Referring toFIG. 4, when the UE fails to detect data410in a random HARQ process, it sends Negative ACKnowledgement (NACK) feedback. When the number of the current HARQ retransmissions is smaller than the maximum number of the retransmissions, the UE sets a HARQ retransmission prediction subframe interval420after two subframes based on the subframe transmitting the NACK feedback and searches resource allocation information in this interval420.

When the UE succeeds in detecting data using the HARQ process, the resource allocation information search time interval ends in the subframe of success. On the other hand, if no data is detected using the corresponding HARQ process, this implies that the necessary size of the search time interval is greater than a specific value. When a certain time passes after the search, the UE finishes the search.

For example, when HARQ retransmission is possible for a maximum of N subframes after the previous transmission, the search time interval spans the next N subframes after the previous transmission.

FIG. 5illustrates a search time interval setting method for a plurality of HARQ processes according to an exemplary embodiment of the present invention.

Referring toFIG. 5, when the eNode B transmits data using the plurality of HARQ processes, retransmission can occur in each HARQ process and the time interval predicted for retransmission in the non-anchor CC can differ per HARQ process.

While two subframes510and550that include resource allocation information are detected in the anchor CC of the UE, a detection error occurs in subframes515and555, which include resource allocation information in the non-anchor CC, and the resulting NACK feedback is generated in two HARQ processes.

In the non-anchor CC, the resource allocation information search time intervals corresponding to the HARQ processes are set to 6 subframes520and5subframes560respectively, such that three subframes overlap. In this case, the search time interval is set to 8 subframes590which is the union of the two time intervals.

In the search time interval of 8 subframes590, the UE waits to detect the resource allocation information in subframes525and565as the failed resource allocation information of subframes515and555.

Now, a description is made of an exemplary resource allocation information search region setting method in which a UE searches resource allocation information of a non-anchor CC.

FIG. 6illustrates a resource allocation information search region setting method of a UE with one HARQ process according to an exemplary embodiment of the present invention.

Referring toFIG. 6, when detecting resource allocation information in subframe610of the anchor CC but failing to detect resource allocation information in subframe615of the non-anchor CC, the UE generates and sends NACK to the eNode B. After two subframes following NACK transmission, the UE searches in a search time interval620to detect retransmission of the failed resource allocation information of subframe615of the non-anchor CC. When the UE searches the resource allocation information in the non-anchor CC, the search space is the same as in the initial resource allocation information search or the retransmitted resource allocation information search.

FIG. 7illustrates a resource allocation information search region setting method of a UE with a plurality of HARQ processes according to an exemplary embodiment of the present invention.

Referring toFIG. 7, when detecting resource allocation information in subframes710and750of the anchor CC but failing to detect resource allocation information in subframes715and755of the non-anchor CC, the UE sends NACK to the appropriate eNode Bs.

As for the first NACK feedback, after two subframes, the UE searches in a search time interval720to detect retransmission of the failed resource allocation information of subframe715in the non-anchor CC. In the resource allocation information search in the non-anchor CC, the search space is the same as in the initial resource allocation information search or the retransmitted resource allocation information search.

However, regarding the second NACK feedback, after two subframes, the UE searches in a search time interval760to detect the retransmission of the failed resource allocation information of subframe765in the non-anchor CC. In the resource allocation information search in the non-anchor CC, the search space is the same as in the initial resource allocation information search or the retransmitted resource allocation information search.

When the search time intervals overlap each other, the later corresponding search space760is used for the search in the overlapped search time interval. That is, when the search time intervals of the resource allocation information of subframes715and755overlap, the search space760of the resource allocation information of subframe765is applied to the search. Herein, the resource allocation information725indicates ACK feedback of the transmit resource.

FIG. 8illustrates a resource allocation information search region setting method of a UE with a plurality of HARQ processes when new resource allocation information is found according to an exemplary embodiment of the present invention.

Referring toFIG. 8, when detecting resource allocation information in subframes810and850of the anchor CC but failing to detect resource allocation information in subframes815and835of the non-anchor CC, the UE sends NACK to each appropriate eNode B.

As for the first NACK feedback, after two subframes, the UE searches in a search time interval820to detect the retransmission of the failed resource allocation information of subframe815of the non-anchor CC. In the resource allocation information search in the non-anchor CC, the search space is the same as in the initial resource allocation information search or the retransmitted resource allocation information search.

However, as for the second NACK feedback, after two subframes, the UE searches in a search time interval860to detect retransmission of the failed resource allocation information of subframe835of the non-anchor CC. In the resource allocation information search in the non-anchor CC, the search space is the same as in the initial resource allocation information search or the retransmitted resource allocation information search.

When the search time intervals overlap each other, a later corresponding search space is used for the search in the overlapped search time interval. That is, when the search time intervals of the resource allocation information865overlap, the search space corresponding to the resource allocation information865is applied to the search.

When the UE additionally detects new resource allocation information in subframe870of the anchor CC, only during the corresponding subframe time interval, the search space of the non-anchor CC for the resource allocation information of subframe870of the anchor CC is applied to the detection of resource allocation information of subframe875in the non-anchor CC.

FIG. 9illustrates a resource allocation information searching process using synchronous HARQ in an uplink according to an exemplary embodiment of the present invention.

Referring toFIG. 9, based on the synchronous manner, when the NACK feedback occurs, the eNode B and the UE are aware of when the retransmitted resource allocation information or the retransmit data is generated in the non-anchor CC.

The subframe time interval carrying ACK/NACK information is the subframe region defined to deliver the resource allocation information. In this subframe interval, the resource allocation information is searched in the anchor CC and the non-anchor CC as well.

The resource allocation information of subframe915is detected in the anchor CC of the downlink910of the UE, and the resource allocation information of subframe920is detected in the non-anchor CC.

Next, while data of subframes955and965is transmitted from the UE to the eNode B in the non-anchor CC of the uplink950, the data reception in the non-anchor CC fails and the NACK feedback of subframe930is generated. In this case, the eNode B can successfully receive the retransmitted data of subframe970of the non-anchor CC though there is no data transmission of the anchor CC in the uplink950.

FIG. 10illustrates a resource allocation information detecting process of a UE according to an exemplary embodiment of the present invention.

Referring toFIG. 10, it is determined if the anchor and non-anchor CCs are set by signaling with the eNode B in step1010. If it is determined in step1010that the anchor and non-anchor CCs are set, the UE detects the resource allocation information in the anchor CC in step1020. On the other hand, if it is determined in step1010that the anchor and non-anchor CCs are not set, the UE sets the anchor and non-anchor CCs by signaling with the eNode B in step1015and detects the resource allocation information in the determined anchor CC in step1020. The signaling follows a procedure defined by the standard.

In step1025, the UE determines if it is to detect resource allocation information in the non-anchor CC. If the UE determines in step1025that it is to detect resource allocation information in the non-anchor CC, the UE detects resource allocation information of the non-anchor CC in step1030and transmits and receives data according to the detected resource allocation information in step1040.

On the other hand, if the UE determines in step1025that it is not to detect resource allocation information in the non-anchor CC, the UE transmits and receives data according to the detected resource allocation information in step1040. The resource allocation information in step1040indicates the previously detected resource allocation information.

When detecting the resource allocation information in the anchor CC, the UE determines the resource allocation information search region of the non-anchor CC according to the resource size and location of the detected resource allocation information.

The search region of the anchor CC is expressed as a function SA(k,m,UEID) and the search region of the non-anchor CC can be expressed as a function SN(k,m,UEID,SD).

In the above functions, k denotes the subframe number, m denotes the CC number, UEID denotes the ID of the UE, and SD denotes the resource size and location of the resource allocation information detected in the anchor CC.

That is, the search region of the anchor CC is determined by the subframe number, the CC number, and the UE ID. The search region of the non-anchor CC is determined by the subframe number, the UE ID, and the resource location and size of the information detected in the anchor CC.

When detecting no resource allocation information in the anchor CC, the UE searches the resource allocation information in the non-anchor CC using the search region used in the past.

For example, the UE can select one of the HARQ processes predicted to deliver the retransmission in the current subframe of the non-anchor CC, and define the resource allocation information search region used in the previous transmission of the selected HARQ process as the search region of the current subframe.

More specifically, the resource allocation information search region of the non-anchor CC is expressed as SN(k,m,UEID,SD_mem), where k denotes the subframe number, UEID denotes the ID of the UE, and SD_mem is defined as follows. That is, when the resource allocation information search region in the non-anchor CC is set to SN(k,m,UEID,SD), the decoding of the received data fails, and the NACK is fed back, SD_mem after two subframes based on the NACK feedback subframe can be set to SD.

FIG. 11illustrates a resource allocation information detecting process of a UE according to an exemplary embodiment of the present invention.

Referring toFIG. 11, the UE initializes variables (N, k) used in the algorithm in step1110. The UE receives the next subframe; that is the subframe to process in step1115. Herein, N denotes the number of pending resource allocation information or data to retransmit, and k denotes the subframe number.

The UE determines the PDCCH search space of the anchor CC in step1120and searches the PDCCH, that is, the resource allocation information in the determined search space in step1125.

In step1130, the UE determines if the PDCCH is detected. Upon detecting the PDCCH, that is, upon detecting the resource allocation information in step1130, the UE receives data in the anchor CC using the resource allocation information in step1140.

Next, the UE sets the resource of the detected PDCCH, that is, the size and the location of the detected resource allocation information to S1in step1145, and sets S1to a search space standard S of the current non-anchor CC (S=S1) in step1150. This represents that the standard S of the search space of the current non-anchor CC is set to S1.

On the other hand, when the PDCCH is not detected in step1130and if it is determined that there exists pending retransmission resource allocation information to receive in the non-anchor CC in step1135, the UE updates the standard of the search space (S=S2) in step1155. S denotes the standard of the search space to use in the current non-anchor CC, and S2denotes the standard of the search space used in the initial transmission of the resource allocation information to retransmit in the non-anchor CC. Namely, the standard of the search space to currently use is set to the standard of the search space previously used.

The UE determines the PDCCH search space in the non-anchor CC using the search space standard S (S,UEID,k) in step1160, and searches the PDCCH of the non-anchor CC, that is, the resource allocation information in the determined search space in step1165. The search space standard setting and the search space setting conform to the procedures defined by the standard.

In step1170, the UE determines if the PDCCH is detected in the non-anchor CC. If it is determined that the UE detects the PDCCH, that is, the resource allocation information in the non-anchor CC in step1170, the UE receives data from the non-anchor CC according to the resource allocation information in step1175.

In step1180, the UE determines if it fails to receive the data of step1175. If it is determined in step1180that there was a failure in reception of the data, the UE updates the standard of the search space (S2=S) to use in the non-anchor CC after M (=6) subframes, that is, stores the standard S of the current search space to S2in step1190.

In step1197, the UE determines if the data that failed to be received is the initial transmission. If the UE determines in step1197that the data that failed to be received in step1175is the initial transmission, the UE increases the number of the pending resource allocation information or data to retransmit, which is to be taken into account after M (=6) subframes, by one in step1199.

If the UE determines in step1180that there is not a data reception failure of step1175is successfully received in step1180, the UE determines in step1185if the successfully received data is a retransmission. If the UE determines in step1185that the successfully received data is retransmitted, the UE decreases the number of the pending resource allocation information or data to retransmit by one in step1195.

Next, the UE receives a next frame in step1115and then repeats the subsequent steps.

In summary, when receiving the resource allocation information in the anchor CC, the UE obtains parameters for determining the search space to use in the non-anchor CC from the resource allocation information, and determines the search space to use in the non-anchor CC using the determined parameters.

Using the determined search space, the UE searches the resource allocation information in the non-anchor CC. Upon detecting the resource allocation information, the UE receives data in the non-anchor CC according to the detected resource allocation information.

When the UE fails to receive the data, the NACK feedback is generated, which is not illustrated. After the NACK feedback, the UE determines whether the data is retransmitted in the corresponding subframe, determined using the search space used when the data reception fails in the non-anchor CC.

The determined corresponding subframe can vary according to the synchronous HARQ or the asynchronous HARQ as stated earlier.

FIG. 12illustrates a search space setting method with a plurality of HARQ processes according to an exemplary embodiment of the present invention.

Referring toFIG. 12, it is determined in step1210if the resource allocation information search time intervals of the non-anchor CC overlap each other. When there is a plurality of HARQ processes and the resource allocation information search time intervals of the non-anchor CC overlap each other, the search time corresponding to the later HARQ process is applied to the overlapping resource allocation information search time intervals in the non-anchor CC in step1220.

That is, when the subframe intervals waiting for retransmission in the non-anchor CC overlap each other, the search space used in the recent HARQ process is applied to the overlapping subframe intervals.

On the other hand, if it is determined in step1210that the resource allocation information search time intervals of the non-anchor CC do not overlap each other, it is determined in step1230if a PDCCH of the newly detected anchor CC is present. When a PDCCH of the newly detected anchor CC is present, that is, when new resource allocation information is detected in the anchor CC in step1230, the search space determined from the newly detected anchor CC is applied to the overlapping resource allocation information search time intervals of the non-anchor CC corresponding to the newly detected anchor CC in step1240.

That is, in step1240, the search space determined from the newly detected anchor CC is applied to the subframe overlapping the non-anchor CC corresponding to the newly detected anchor CC.

FIG. 13is a block diagram of a UE according to an exemplary embodiment of the present invention.

Referring toFIG. 13, the UE includes a transceiver duplexer1310, a receiver1315, a transmitter1320, a resource extractor and allocator1330, a resource allocation information detector1340, a demodulator and decoder1345, a modulator and encoder1350, a carrier aggregation setter1360, and a data buffer1365.

Based on the duplexing scheme, the transceiver duplexer1310forwards a receive signal from an antenna to the receiver1315, and transmits a signal output from the transmitter1320over the antenna.

The receiver1315converts a Radio Frequency (RF) signal output from the transceiver duplexer1310to an analog signal, converts the analog signal to sample data, and outputs the sample data to the resource extractor and allocator1330.

The transmitter1320converts the output data from the resource extractor and allocator1330to an analog signal, converts the analog signal to an RF signal, and outputs the RF signal to the transceiver duplexer1310.

The resource extractor and allocator1330extracts the corresponding resource from the sample data output from the receiver1315according to its anchor CC and non-anchor CC, and outputs the extracted resource to the demodulator and decoder1345. Alternatively, the resource extractor and allocator1330includes the data output from the modulator and encoder1350with its anchor CC and non-anchor CC and outputs the data to the transmitter1330.

The demodulator and decoder1345demodulates and decodes the output data from the resource extractor and allocator1330according to a defined demodulation and decoding scheme, and outputs the data to the data buffer1365by subframes.

The modulator and encoder1350modulates and encodes the output data from the data buffer1365according to a defined modulation and encoding scheme, and outputs the data to the resource extractor and allocator1330.

The data buffer1365stores the subframes output from the demodulator and decoder1345and outputs the stored data to the upper layer. The data buffer1365also stores data received from the upper layer and outputs the stored data to the modulator and encoder1350.

The resource allocation information detector1340searches the resource allocation information in the anchor CC per subframe received, searches the resource allocation information of the non-anchor CC in the defined time interval, and outputs the results to the resource extractor and allocator1330. The time interval and the search region for the resource allocation information search of the non-anchor CC are determined by the resource allocation information detector1340according to the data transmission and reception result. The resource allocation information detected in the anchor and non-anchor CCs is forwarded to the resource extractor and allocator1330, and the data transmission and reception is performed using the corresponding resource.

The carrier aggregation setter1360determines the anchor and non-anchor CCs by signaling with the eNode B.

Herein, a controller, which is not illustrated, can function as the resource allocation information detector1340and the carrier aggregation setter1360.

In an exemplary implementation, the controller can process all or part of the functions of the resource allocation information detector1340and the carrier aggregation setter1360.

FIG. 14illustrates operations of an eNode B according to an exemplary embodiment of the present invention.

Referring toFIG. 14, the eNode B determines in step1410if the anchor and non-anchor CCs are set by signaling with the UE. When it is determined in step1410that the anchor and non-anchor CCs are set, the eNode B generates the resource allocation information for the corresponding UE in step1420and determines the transmit resource for carrying the resource allocation information in step1425. The signaling conforms to the procedure defined by the standard.

The eNode B transmits the resource allocation information to the corresponding UE in step1430and transmits and receives data to and from the corresponding UE according to the resource allocation information in step1440.

When it is determined that the anchor and non-anchor CCs are not defined in step1410, the eNode B sets the anchor and non-anchor CCs by signaling with the UE in step1415.

Next, the eNode B generates the resource allocation information for the corresponding UE in step1420and determines the transmit resource for carrying the resource allocation information in step1425.

The eNode B transmits the resource allocation information to the corresponding UE in step1430and transmits and receives data to and from the corresponding UE according to the resource allocation information in step1440.

During generation of the resource allocation information for retransmission, the eNode B generates the resource allocation information such that the resource for the retransmission is included only for the non-anchor CC, not for the anchor CC. The eNode B identically defines the search space of the non-anchor CC in the retransmission as in the non-anchor CC band of the initial transmission.

FIG. 15is a block diagram of an eNode B according to an exemplary embodiment of the present invention.

Referring toFIG. 15, the eNode B includes a transceiver duplexer1510, a receiver1515, a transmitter1520, a resource extractor and allocator1525, a demodulator and decoder1530, a modulator and encoder1535, a carrier aggregation setter1540, a data buffer1550, and resource allocation information generator1560.

Based on the duplexing scheme, the transceiver duplexer1510forwards a received signal from an antenna to the receiver1515, and transmits a signal output from the transmitter1520over the antenna.

The receiver1515converts an RF signal output from the transceiver duplexer1510to an analog signal, converts the analog signal to sample data, and outputs the sample data to the resource extractor and allocator1525.

The transmitter1520converts output data from the resource extractor and allocator1525to an analog signal, converts the analog signal to an RF signal, and then outputs the RF signal to the transceiver duplexer1510.

The resource extractor and allocator1525extracts the corresponding resource from the sample data output from the receiver1515according to its anchor CC and non-anchor CC, and outputs the extracted resource to the demodulator and decoder1530. Alternatively, the resource extractor and allocator1525includes the output data from the modulator and encoder1535to the resource information, that is, to its anchor CC and non-anchor CC and outputs the data to the transmitter1520.

The demodulator and decoder1530demodulates and decodes the resource output from the resource extractor and allocator1525according to a defined demodulation and decoding scheme, and outputs the data to the data buffer1550by subframes.

The modulator and encoder1535modulates and encodes the output data from the data buffer1550according to a defined modulation and encoding scheme, and outputs the data to the resource extractor and allocator1525.

The data buffer1550stores the subframes output from the demodulator and decoder1530and outputs the stored data to the upper layer. The data buffer1550stores data received from the upper layer and outputs the stored data to the modulator and encoder1530.

The resource allocation information generator1560determines the transmission resource for transmitting to and receiving from each UE, per subframe, and generates the resource allocation information for the UE. The generated resource allocation information is forwarded to the resource extractor and allocator1525and transmitted to and received from the UEs over the corresponding resources.

The carrier aggregation setter1540determines the anchor and non-anchor CCs by signaling with the UE.

Herein, a controller, which is not illustrated, can function as the carrier aggregation setter1540and the resource allocation information generator1560.

In an exemplary implementation, the controller can process all or part of the functions of the carrier aggregation setter1540and the resource allocation information generator1560.

By addressing the high reception complexity and the HARQ retransmission constraints, the HARQ retransmission can be accomplished with the low reception complexity and the non-anchor CC alone.