KR20130017243A - Apparatus and method for transmitting control channel in wireless communication system - Google Patents

Abstract

PURPOSE: A transmitting apparatus of a control channel in a wireless communication system and a method thereof are provided to obtain a frequency diversity gain by using a resources block hopping in a resource block aggregation unit. CONSTITUTION: A base station transmits the cluster configuration to a terminal(S500). The base station can transmit X-PDCCH in SCR. The base station transmits a SCR activation indicator to the terminal(S505). The SCR activation indicator can be transmitted by upper level signaling such as RRC message. The base station transmits a cluster configuration parameter to the terminal(S510). The base station transmits X-PDCCH to the terminal through SCR of the subframe(S515). The terminal monitors X-PDCCH candidates in SCR of the subframe(S520). [Reference numerals] (AA) Terminal; (BB) Base station; (S500) Cluster configuration; (S505) Subsidiary control region activation indicator; (S510) Cluster configuration parameter; (S515) X-PDCCH(source block hopping on/off); (S520) Monitoring X-PDCCH candidates

Description

Apparatus and method for transmitting control channel in wireless communication system {APPARATUS AND METHOD FOR TRANSMITTING CONTROL CHANNEL IN WIRELESS COMMUNICATION SYSTEM}

The present invention relates to wireless communication, and more particularly, to an apparatus and method for transmitting a control channel in a wireless communication system.

In a wireless communication system, generally, one base station provides a service to a plurality of terminals. The base station schedules data for a plurality of terminals and transmits control information about the data together with the data. In general, a channel carrying control information is called a control channel, and a channel carrying data is called a data channel. The terminal acquires its own control information by monitoring the control channel, and processes its data using the control information. Monitoring means that the terminal attempts to decode the control channel candidates.

According to the prior art, the terminal must receive the control information for the data in order to receive its data. However, in a given bandwidth, control channels of a plurality of terminals are generally multiplexed within one transmission interval. That is, the base station transmits a plurality of control channels for the plurality of terminals to provide services to the plurality of terminals. The terminal finds its own control channel among the plurality of control channels. If the terminal does not correctly detect its control channel from the multiplexed control channels, it is not possible to decode the data channel. In addition, when it is necessary to transmit a control channel to a plurality of terminals in a hot spot or a crowded area, the capacity of the control channel increases.

Although the radio resources for the control channel is limited, the prior art does not disclose a method that can efficiently support the increasing capacity of the control channel.

An object of the present invention is to provide an apparatus and method for transmitting a control channel in a wireless communication system.

Another object of the present invention is to provide an apparatus and method for receiving a control channel in a wireless communication system.

Another technical problem of the present invention is to provide an apparatus and method for transmitting a downlink control channel to a resource block in a data region.

Another technical problem of the present invention is to provide an apparatus and method for transmitting a downlink control channel by resource block hopping in a sub-control region.

Another object of the present invention is to provide an apparatus and method for allocating a cluster of a sub-control area on a resource block basis.

Another technical problem of the present invention is to provide an apparatus and method for transmitting a cluster configuration for a sub-control region and information about a downlink control channel.

According to an aspect of the present invention, a method of transmitting a control channel by a base station in a subframe including a main control region and a data region is provided. The method may include allocating the data area to a sub control area including a cluster including one or more adjacent resource blocks at a specific location, transmitting a cluster number indicator indicating the number of clusters to a terminal. Mapping a physical downlink control channel to resource blocks specified by the number of clusters; and transmitting the mapped physical downlink control channel to the terminal.

According to another aspect of the present invention, there is provided a base station for transmitting a control channel in a subframe including a main control region and a data region. The base station allocates the data area to a sub control area including a cluster composed of one or more adjacent resource blocks at a specific location, and generates a cluster number indicator indicating the number of clusters, and the number of clusters. And a transmitter for mapping a physical downlink control channel to the resource blocks specified by and transmitting the mapped physical downlink control channel to the terminal.

According to another aspect of the present invention, a method for receiving a control channel by a terminal in a subframe including a main control region and a data region is provided. The method includes receiving from the base station a cluster number indicator indicating the number of clusters consisting of one or more contiguous resource blocks of a particular location within the data area, and the resources in the sub-control area specified by the number of clusters. Decoding candidates of the physical downlink control channel mapped to the blocks in a predetermined resource block aggregation unit.

According to another aspect of the present invention, a terminal for receiving a control channel in a subframe including a main control region and a data region is provided. The terminal receives from the base station a cluster number indicator indicating the number of clusters consisting of one or more adjacent resource blocks of a specific position in the data area, and the resource blocks in the sub-control area specified by the number of clusters. A receiver which decodes candidates of the physical downlink control channel mapped to the predetermined resource block aggregation unit, the number of resource blocks in the sub-control region determined by the system bandwidth of the terminal, and the resource block aggregation unit. And a processor for providing information to the receiver.

The control channel is transmitted by hopping in units of resource blocks in the data region to obtain a frequency diversity gain, and the reliability of decoding of the terminal can be increased.

1 shows a wireless communication system to which the present invention is applied.
2 shows a structure of a subframe to which the present invention is applied.
3 is a diagram illustrating embodiments of resource allocation to which the present invention is applied.
4 is a diagram showing another embodiment of resource allocation to which the present invention is applied.
5 is a flowchart illustrating a method of transmitting an extended control channel according to an embodiment of the present invention.
6 is a diagram illustrating an example of a resource block hopping pattern according to an embodiment of the present invention.
7 is a diagram illustrating an example of a resource block hopping pattern according to another example of the present invention.
8 is a diagram illustrating an example of a resource block hopping pattern according to another embodiment of the present invention.
9 is a diagram illustrating an example of a resource block hopping pattern according to another embodiment of the present invention.
10 is a flowchart illustrating an operation of a terminal according to an embodiment of the present invention.
11 is a view illustrating a monitoring method of a terminal according to an embodiment of the present invention.
12 is a diagram illustrating a monitoring method of a terminal according to another example of the present invention.
13 is a flowchart illustrating an operation of a base station according to an embodiment of the present invention.
14 is a block diagram of a base station and a terminal according to an embodiment of the present invention.

Hereinafter, some embodiments will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear.

In describing the components of the present specification, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; may be "connected," "coupled," or "connected. &Quot;

In addition, the present invention will be described with respect to a wireless communication network. The work performed in the wireless communication network may be performed in a process of controlling a network and transmitting data by a system (e.g., a base station) Work can be done at a terminal connected to the network.

According to embodiments of the present invention, 'transmitting a control channel' may be interpreted as meaning that control information is transmitted through a specific channel. Here, the control channel may be, for example, a physical downlink control channel (PDCCH) or a physical uplink control channel (PUCCH).

1 shows a wireless communication system to which the present invention is applied.

Referring to FIG. 1, a wireless communication system 10 is widely deployed to provide various communication services such as voice, packet data, and the like. The wireless communication system 10 includes at least one base station 11 (BS). Each base station 11 provides a communication service for a particular geographic area or frequency area (generally called a cell) 15a, 15b, 15c. The cell may again be divided into multiple regions (referred to as sectors).

A mobile station (MS) 12 may be fixed or mobile and may be a user equipment (UE), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, (personal digital assistant), a wireless modem, a handheld device, and the like. The base station 11 generally refers to a station that communicates with the terminal 12, and includes an evolved-NodeB (eNB), a base transceiver system (BTS), an access point, an femto eNB, and a home. It may be called other terms such as a base station (Home eNB: HeNB), a relay, and the like. The cell should be interpreted in a generic sense to indicate a partial area covered by the base station 11 and is meant to cover various coverage areas such as a megacell, a macro cell, a microcell, a picocell, and a femtocell.

Hereinafter, downlink refers to a communication or communication path from the base station 11 to the terminal 12, and uplink refers to a communication or communication path from the terminal 12 to the base station 11. . In the downlink, the transmitter may be part of the base station 11, and the receiver may be part of the terminal 12. In the uplink, the transmitter may be part of the terminal 12, and the receiver may be part of the base station 11. There is no limitation on the multiple access scheme applied to the wireless communication system 10. (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier-FDMA , OFDM-CDMA, and the like. The uplink transmission and the downlink transmission may use a time division duplex (TDD) scheme transmitted using different times or a frequency division duplex (FDD) scheme transmitted using different frequencies.

2 shows a structure of a subframe to which the present invention is applied.

Referring to FIG. 2, a subframe includes two consecutive slots. The preceding 1 to 3 OFDM symbols of the first slot in the subframe are used as a primary control region (PCR) to which the PDCCH is mapped, and the remaining OFDM symbols are the data region or extended PDCCH to which the PDSCH is mapped. (eXtended-PDCCH: X-PDCCH) is used as a secondary control region (SCR) to which it is mapped. In addition to the PDCCH, a control channel such as PCFICH and PHICH may be allocated to the main control region. The number of OFDM symbols to which the main control region is mapped in the subframe can be known through the PCFICH. The UE may read data information transmitted through the PDSCH by decoding the PDCCH or the X-PDCCH.

The main control area is insufficient to support the control information necessary to support technologies such as multi-user MIMO (MU_MIMO), coordinated multiple point (CoMP), carrier aggregation (CA), and the like. The sub control area is a control area provided in the data area due to the lack of such a main control area. In case of time division multiplexing (TDM) scheme, the sub control region is time division multiplexed in the data domain, and in case of frequency division multiplexing (FDM) scheme, the secondary control region is frequency in the data domain. Division multiplexing. Since the X-PDCCH is transmitted in the data region, the UE may demodulate the X-PDCCH based on a channel estimated from a demodulation reference signal (DM-RS), which is a method of receiving a PDCCH and May be different.

The sub control area according to the FDM method has the following characteristics. i) A closed loop demodulation gain may exist due to a UE specific demodulation reference signal. ii) In the case of the linked multi-point method, transmission is possible at the best transmission point. iii) Common Reference Signal (CRS) and PDCCH transmission may be omitted. Because of this, it can be used for an extension carrier. iv) Interference coordination is possible. v) individual power boosting is possible. vi) Since there is no interleaving, the interference randomization effect is reduced compared to the conventional PDCCH. vii) Power consumption and processing delays may occur.

However, when the X-PDCCH is transmitted by frequency hopping, since the interference randomization and frequency diversity effects are obtained, disadvantages such as vi) may be solved.

The main control area is composed of a stream of a plurality of control channel elements (CCEs). Hereinafter, the CCE column is a collection of all CCEs constituting the control region in one subframe. The CCE corresponds to a plurality of resource element groups. For example, the CCE may correspond to nine resource element groups. Resource element groups are used to define the mapping of control channels to resource elements. For example, one resource element group may consist of four available resource elements (resources that can be transmitted for a control channel except for CRS, etc.).

A plurality of PDCCHs may be transmitted in the main control region. Downlink control information (DCI), such as scheduling assignment, is mapped to the PDCCH. The DCI transmits uplink or downlink scheduling information, an uplink power control command, control information for paging, control information for indicating a random access response, and the like.

The PDCCH is transmitted on the aggregation of one or several consecutive control channel elements (CCEs). The format of the PDCCH and the number of bits of the PDCCH are determined according to the number of CCEs constituting the CCE aggregation unit. Hereinafter, the number of CCEs used for PDCCH transmission is called a CCE aggregation level. In addition, the CCE aggregation unit is a CCE unit for searching for a PDCCH. The size of a CCE aggregation unit is defined by the number of adjacent CCEs. For example, the CCE aggregation unit may be an element of {1, 2, 4, 8}.

The following table shows an example of the format of the PDCCH according to the CCE aggregation unit and the number of bits of the PDCCH available.

PDCCH format CCE Aggregation Unit Number of resource element groups Number of PDCCH bits 0 One 9 72 One 2 18 144 2 4 36 288 3 8 72 576

Referring to Table 1, when the PDDCH format is 1, the CCE aggregation unit is 2, the number of resource element groups is 18, and the number of bits transmitted on the coded PDCCH physical link is 144 bits. That is, one CCE aggregation unit is mapped to nine resource element groups, and one resource element group corresponds to 9 bits.

The secondary control region is included in the data region. Resources reserved for the secondary control region may be fixed or may be changed by the base station. In addition, the sub control region may or may not be included in the data region from time to time. For example, when the base station can sufficiently transmit the control information only to the main control area and the sub control area is not necessary, the sub control area may not be included in the data area. In any case, in order for the base station to transmit the X-PDCCH on the secondary control region, the base station must first designate resources of the secondary control region in the data region. And the base station should indicate to the terminal that the scheduling (scheduling) of the X-PDCCH is enabled (enable). Hereinafter, a description will be mainly given of a sub control region according to the FDM scheme, but this may be applied to the sub control region according to the TDM scheme.

The sub control area is composed of at least one cluster. Here, a cluster is a resource zone composed of one or more adjacent resource blocks (RBs) at a specific location. A resource block is defined as a physical quantity, as N ^DL _symb consecutive OFDM symbols in the time domain and as N ^RB _SC consecutive subcarriers in the frequency domain. Therefore, one resource block is composed of N ^DL _symb x N ^RB _SC resource elements. Resource blocks are indexed from 0 to N ^DL _RB -1 in the frequency domain.

3 is a diagram illustrating embodiments of resource allocation to which the present invention is applied.

Referring to FIG. 3, Embodiment 1 is a resource allocation method of type 0 or 1, Embodiment 2 is a resource allocation method of type 2, and Embodiment 3 is a resource allocation method of type 3.

In Embodiment 1, the resource allocation method of type 0 or 1 allocates resources in units of resource block groups (RBGs). A resource block group is a resource unit handled when allocating a resource. The resource block group includes one resource block or two or more contiguous resource blocks, and an amount of resources corresponding to multiples of the resource block group is allocated to the terminal. . For example, suppose p resource blocks are one resource block group, and an N _RB resource block group is allocated to the terminal. In this case, the total amount of resources allocated to the terminal is pN _RB . In a resource allocation method of type 0 or 1, one resource block group includes 1 to 4 resource blocks.

Type 0 or 1 resource allocation schemes support only localized virtual resource block (LVRB) mapping. This means that the resource allocation method of type 0 and 1 transmits using the same frequency band for each slot in one subframe. Meanwhile, the type 0 resource allocation method allocates a resource block group to a terminal using a bitmap format. In addition, in the type 1 resource allocation scheme, the base station allocates a resource block group to the terminal at predetermined intervals or periods.

In Embodiment 2, the type 2 resource allocation scheme allocates resource blocks as contiguous constant length regions. The number of bits required for the Type 2 resource allocation scheme depends on the bandwidth of the system. The maximum value may be 13 bits. Type 2 resource allocation supports both local virtual resource block (LVRB) mapping and distributed virtual resource block (VRB) mapping. That is, in transmitting data, the type 2 resource allocation scheme may use the same frequency for each slot or different frequency bands.

In Embodiment 3, the type 3 resource allocation scheme increases the granularity in resource block allocation than the type 0, 1 and 2 resource allocation schemes. This is because type 3 allocates resources in resource block units according to a specific allocation pattern, unlike types 0 and 1 that allocate resources in resource block group units. Type 3 resource allocation uses at least one cluster as a cell specific sub-control area. The base station transmits a configuration (hereinafter, simply referred to as a 'cluster configuration') related to the number and location of clusters included in the secondary control region to the terminal through signaling of a higher layer. For example, the signaling of the higher layer may include a radio resource control (RRC) message. On the other hand, the cluster configuration is cell specific, and is commonly applied to all terminals receiving the same.

Among the resource blocks corresponding to the system band, the position of the cluster used as the sub control region is determined depending on the number of clusters. For example, when the total number of resource blocks allocated to the secondary control region is N, the cluster configuration may be determined as shown in the following table.

Bit information Number of clusters Cluster location 00 One RB # 0 ~ RB # (N-1) 01 2 RB # 0 ~ RB # (N / 2-1), RB # [N ^BW _RB- (N / 2-1)] ~ RB # (N ^BW _RB -1) 10 4

~RB#[

-(N/4-1)],
RB#

~RB#[

-(N/4-1)],
RB#[(N^BW _RB-1)-(N/4-1)]~RB#(N^BW _RB-1)RB # 0 ~ RB # (N / 4-1),
RB #

~ RB # [

-(N / 4-1)],
RB #

~ RB # [

-(N / 4-1)],
RB # [(N ^BW _RB -1)-(N / 4-1)] to RB # (N ^BW _RB -1) 11 8 RB # 0 ~ RB # (N / 8-1),
RB #

~ RB # [

-(N / 8-1)],
RB #

~ RB # [

-(N / 8-1)],
RB #

~ RB # [

-(N / 8-1)],
RB #

~ RB # [

-(N / 8-1)],
RB #

~ RB # [

-(N / 8-1)],
RB #

~ RB # [

-(N / 8-1)],
RB # [(N ^BW _RB -1)-(N / 8-1)] to RB # (N ^BW _RB -1)

Referring to Table 2, the sub control region may include 1, 2, 4, or 8 clusters. In addition, the positions of the clusters are individually defined for each cluster number. For example, if there is only one cluster, the position of the cluster is the resource block (RB) indexes # 0 to #N. Alternatively, for example, if the number of clusters is 4, N ^BW _RB = 64, N = 16, as shown in FIG. 4, cluster 0 is RB # 0 to RB # 3, and cluster 1 is RB # 13 to RB #. 16, cluster 2 is RB # 29 to RB # 32, and cluster 3 is RB # 60 to RB # 63.

~RB#[

-(N/8-1)], 클러스터 2는 RB#

~RB#[

-(N/8-1)], 클러스터 3은 RB#

~RB#[

-(N/8-1)], 클러스터 4는 RB#

~RB#[

-(N/8-1)], 클러스터 5는 RB#

~RB#[

-(N/8-1)], 클러스터 6은 RB#

~RB#[

-(N/8-1)], 클러스터 7은 RB#[(N^BW _RB-1)-(N/8-1)]~RB#(N^BW _RB-1)이다. 표 2에서 클러스터의 수가 다르면 클러스터의 위치도 달라지나, 모든 클러스터내의 총 자원블록의 합은 N으로 일정하다. If the number of clusters is 8, cluster 0 is RB # 0 ~ RB # (N / 8-1), cluster 1 is RB #

~ RB # [

-(N / 8-1)], cluster 2 is RB #

~ RB # [

-(N / 8-1)], cluster 3 is RB #

~ RB # [

-(N / 8-1)], cluster 4 is RB #

~ RB # [

-(N / 8-1)], cluster 5 is RB #

~ RB # [

-(N / 8-1)], cluster 6 is RB #

~ RB # [

-(N / 8-1)] and cluster 7 are RB # [(N ^BW _RB- 1)-(N / 8-1)] to RB # (N ^BW _RB- 1). In Table 2, if the number of clusters is different, the positions of the clusters are different, but the sum of total resource blocks in all clusters is constant N.

The cluster configuration shown in Table 2 may be known in advance between the terminal and the base station, or the base station may inform the terminal as an upper layer message such as an RRC message.

Meanwhile, the total number N of resource blocks allocated to the sub control region may be determined according to a system bandwidth. The following table is an example of N given according to the system bandwidth.

System Bandwidth (BW) N Nc Supported Resource Block Aggregation Units (AL) 1.4 MHz 6 1,2 One 3 MHz 12 1,2,4 1,2 others 16 1,2,4,8 1,2,4,8

Referring to Table 3, a possible value of N may be determined to be 6, 12, or 16 according to the system bandwidth, and accordingly, also supported resource block (RB) aggregation unit AL may be determined. Resource block aggregation unit means the number of resource blocks constituting one X-PDCCH. And Nc may be determined by any one of 1, 2, 4, 8. For example, Nc corresponding to BW = 1.4 MHz is any one of 1, 2, Nc corresponding to BW = 3 MHz is any one of 1, 2, 4, and Nc corresponding to other BW is 1, 2, It is either 4 or 8. AL may also have a value of 1, 2, 4, or 8 depending on the system bandwidth. Since the system bandwidth is already known between the terminal and the base station, even if the base station does not separately signal the N value to the terminal, the terminal may find N based on the system bandwidth and Table 3 above. Of course, the system bandwidth is not necessarily fixed at 1.4 MHz and 3 MHz as shown in Table 3, and may be adjusted according to the situation, and N and AL may be adjusted accordingly. Here, AL refers to the number of resource blocks forming one X-PDCCH and can be adjusted by the base station according to the channel environment.

Here, the possible values of N are illustrated as 6, 12, and 16, but may also be given as 2, 4, 8, and 16. However, since AL must cover all 8, it is effective that N is basically composed of 16, and may be configured with a larger value such as N = 32. However, if the system bandwidth is narrow, it may be configured with a smaller value such as N = 6, 12. For example, possible N per system bandwidth may be given as shown in the following table.

System Bandwidth (BW) Total number of system resource blocks N (in RB pair) 1.4 6 2 3 15 4 or 8 5 25 4 or 8 or 16 10 50 4 or 8 or 16 15 75 4 or 8 or 16 or 32 20 100 4 or 8 or 16 or 32

Hereinafter, a method of transmitting an X-PDCCH by a base station on a secondary control region and a method of receiving an X-PDCCH by a terminal will be described.

5 is a flowchart illustrating a method of transmitting an extended control channel according to an embodiment of the present invention.

Referring to Figure 5, the base station transmits the cluster configuration to the terminal (S500). The cluster configuration may be transmitted to the terminal by higher layer signaling such as an RRC message. For example, the base station may include a cluster configuration in an RRC connection establishment message or an RRC connection reconfiguration message and transmit it to the terminal. However, if the cluster configuration between the terminal and the base station is pre-provisioned, the base station does not need to separately transmit the cluster configuration to the terminal. In this case, step S500 can be omitted. As an example, the cluster configuration may be defined as shown in Table 2 above. If a cluster configuration is defined, there may be a secondary control area in the data area. Furthermore, the base station can transmit the X-PDCCH in the secondary control region.

The base station transmits a secondary control region activation indicator (SCR activation indicator) to the terminal (S505). The secondary control region activation indicator indicates whether the secondary control region is activated (or present) or deactivated (or nonexistent) in the data area. The activation of the secondary control region is a state in which scheduling of the X-PDCCH is enabled. As an example, the sub control region activation indicator indicates 1 bit as '1' to activate the sub control region and '0' to deactivate the sub control region. Activation of the secondary control region means that resources for the secondary control region are allocated in the data region. On the other hand, deactivation of the secondary control region means that resources for the secondary control region are not allocated in the data region. The secondary control region activation indicator may be transmitted by higher layer signaling such as an RRC message.

The secondary control region activation indicator has the following characteristics. First, the secondary control region is used as a means for overcoming a situation in which the primary control region bears the PDCCH. Therefore, it is not necessary to activate the secondary control region in a situation sufficient to transmit the PDCCH to the primary control region. That is, the secondary control region activation indicator is used to adaptively activate the secondary control region according to the situation. The terminal needs to monitor the secondary control region only when the secondary control region is activated. As a result, the UE monitors the sub-control area uniformly to prevent the battery from being consumed.

Second, the terminal may be classified into a terminal having a capability of monitoring the secondary control region (hereinafter referred to as an 'evolved terminal') and a terminal which does not (hereinafter referred to as a 'legacy terminal'). The evolved terminal may receive the X-PDCCH by monitoring the secondary control region, but the legacy terminal may not recognize the secondary control region in the data region and may not receive the X-PDCCH. In the communication environment, both the evolved terminal and the legacy terminal exist, and the base station must support all of them, so that the evolved terminal can inform whether the secondary control region is monitored through the secondary control region activation indicator. In this sense, activation of the secondary control region may be terminal-specifically indicated. That is, the secondary control region activation indicator may be transmitted only to the evolved terminal.

Here, the sub-control region activation indicator has been described as separate signaling from the cluster configuration, but this is only an example, and the cluster configuration and the sub-control region activation indicator may be included in one signaling and transmitted to the terminal at the same time. Alternatively, the cluster configuration and the secondary control region activation indicator may be transmitted to the terminal at the same time as different signaling.

In a state where both the base station and the terminal know both the cluster configuration, the base station transmits a cluster configuraiton parameter to the terminal (S510). In this case, the base station may transmit the cluster configuration parameter only to the terminal (or evolved terminal) capable of scheduling the X-PDCCH. The cluster configuration parameter is information required for cluster configuration and includes a cluster number indicator. The cluster number indicator is information indicating the number of clusters. According to Table 2, there are four types of clusters: 1, 2, 4, and 8. Therefore, the number of bits needed to represent the number of clusters is two. For example, in Table 2, if the cluster number indicator is 00, the number of clusters is 1, if 01, the number of clusters is 2, if 10, the number of clusters is 4, and if 11, the number of clusters is 8.

From the number of clusters by the cluster number indicator and the cluster configuration, the terminal may determine the position and size of the sub-control region designated by the base station. For example, if the number of clusters in Table 2 is 2, the UE has a cluster 0 of RB # 0 to RB # (N / 2-1) and RB # [(N ^BW _RB -1)-(N / 2-1)] to RB # (N ^BW _RB -1). The position and size of the sub control area determined by the cluster number indicator are determined cell-specific.

The base station transmits the X-PDCCH to the terminal through the sub-control region of the subframe (S515). The X-PDCCH is designed based on resource block units, not interleaving. The sub control region includes resource blocks distributed over two slots in a subframe. Resource blocks in the secondary control region used by the X-PDCCH are designated by a specific pattern. The X-PDCCH may use at least one resource block in each of two slots in a subframe. For example, the X-PDCCH may use resource block 1 in slot 1 and resource block 2 in slot 2. Here, the resource blocks 1 and 2 correspond to different frequency bands, and constitute a pair of RB pairs. As such, the mapping of the X-PDCCH to resource blocks of different frequency bands in each slot is referred to as resource block hopping. Resource block hopping provides a frequency diversity gain. A method of configuring a pair of resource blocks will be described later.

As an example, resource block hopping may be optionally supported. For example, when the terminal communicates in a poor channel environment, resource block hopping may be set to 'on'. On the other hand, when the channel environment is good and frequency diversity gain is unnecessary, resource block hopping may be set to 'off'. On / off of such resource block hopping may be provided by an RB hopping flag. For example, the resource block hopping flag is 1 bit and '1' may mean 'on' of resource block hopping and '0' may mean 'off' of resource block hopping. The RB flag may be included in higher layer signaling, for example, an RRC message or a MAC message, transmitted by the base station to the terminal.

The UE monitors X-PDCCH candidates in the sub-control region of the subframe (S520). Monitoring is performed in all non-discondinuous reception (non-DRX) subframes. Here, monitoring refers to an operation of decoding each of the X-PDCCHs according to all DCI formats, and may be referred to as blind decoding or blind detection. The pair of RBs is a minimum RB unit for the UE to monitor X-PDCCH candidates.

Hereinafter, a resource block hopping pattern and a method of monitoring UE X-PDCCH candidates are described in detail.

6 is a diagram illustrating an example of a resource block hopping pattern according to an embodiment of the present invention.

Referring to FIG. 6, a subframe includes slot 0 and slot 1 on a time axis, and the first 1 to 3 OFDM symbols of slot 0 constitute a main control region. The remaining OFDM symbols in slot 0 and all the OFDM symbols in slot 1 constitute a data region or a sub control region. Physical resource blocks constituting the secondary control region are indexed by m or m '. For example, resource blocks included in slot 0 are identified by index m, and indexes of resource blocks are sequentially m = 0, 1, 2, and 3 along the frequency axis. Resource blocks included in slot 1 are identified by index m ', and indexes of resource blocks are sequentially m' = 0, 1, 2, and 3 along the frequency axis. The total number of resource blocks allocated to the secondary control region is 4 and the number of clusters is 2. That is, one cluster includes two resource blocks.

Resource block hopping is a pattern in which a pair of resource blocks are symmetric about the frequency axis. For example, the X-PDCCH is mapped to a resource block (m = 0) in slot 0 and mapped to a resource block (m '= 3) that is symmetric with respect to the center frequency of the entire system band in slot 1. Resource block (m = 0) and resource block (m '= 3) constitute a pair of resource blocks. Alternatively, the X-PDCCH is mapped to a resource block (m = 3) in slot 0, and is mapped to a resource block (m '= 0) symmetric with respect to the center frequency of the entire system band in slot 1. Resource block (m = 3) and resource block (m '= 0) constitute a pair of resource blocks. As such, the pair of resource blocks is determined according to an accurate symmetric pattern. According to the symmetric pattern, the resource block hopping can be simplified because the position of the pair of resource blocks to be hopped is fixed.

The X-PDCCH may be mapped to an RB in resource block aggregation units 1 and 2, for example. UE1 and UE2 have a resource block aggregation unit of 1 and UE3 has a resource block aggregation unit of 2. The X-PDCCH for UE1 is mapped to a resource block (m = 0) and a resource block (m '= 3) by a symmetric pattern. The X-PDCCH for UE2 is mapped to a resource block (m = 3) and a resource block (m '= 0) by a symmetric pattern. The X-PDCCH for UE3 is mapped to a resource block (m = 1), a resource block (m '= 2) and a resource block (m = 2) and a resource block (m' = 1) by a symmetric pattern. Accordingly, UE1 and UE2 monitor the sub control region in resource block aggregation unit 1, and UE3 monitors the sub control region in resource block aggregation unit 2. The order of resource blocks to be monitored is the same as the symmetric pattern. That is, each UE has a resource block (m = 0), a resource block (m '= 3), a resource block (m = 1), a resource block (m' = 2), a resource block (m = 2), a resource block ( m- = 1), resource block (m = 3), and resource block (m '= 0) in order to monitor the X-PDCCH candidates. Of course, this is an example and the order of the resource blocks monitored by the terminal may be equally applicable to any form of maintaining a symmetrical pattern.

The symmetric pattern is not possible to be two clusters as shown in Figure 6, it is also applicable to the case of four, eight or more clusters. However, when the number of clusters increases, the frequency diversity gain for the X-PDCCH mapped to a specific resource block pair may be smaller than when the number of clusters is two. That is, when the number of clusters is not large, a larger frequency diversity gain can be obtained.

7 is a diagram illustrating an example of a resource block hopping pattern according to another example of the present invention.

Referring to FIG. 7, the total number of resource blocks allocated to the sub control area is 4 and the number of clusters is 4. That is, one cluster includes one resource block. The base station transmits the X-PDCCH to the terminal on the subframe based on resource block hopping. Resource block hopping is performed in units of a pair of resource blocks (m, m '), and a pair of resource blocks (m, m') may be associated by the following equation.

Referring to Equation 1, m 'is the index of the resource block of the slot 1, m is the index of the resource block of the slot 0. N is a value representing the resource allocated to the secondary control region in resource block units. If the index of the RB in slot 0 is determined to be m, the index of the RB in slot 1 paired with it is determined to be m 'by Equation 1 above.

For example, the X-PDCCH is mapped to a resource block (m = 0) in slot 0 and mapped to a resource block (m '= 2) that is symmetric with respect to the center frequency of the entire system band in slot 1. That is, a resource block (m = 0) and a resource block (m '= 2) constitute a pair of resource blocks. Alternatively, the X-PDCCH is mapped to a resource block (m = 2) in slot 0 and mapped to a resource block (m '= 0) that is symmetric with respect to the center frequency of the entire system band in slot 1. That is, the resource block m = 2 and the resource block m '= 0 constitute a pair of resource blocks. According to the pattern according to Equation 1, resource block hopping can be simplified because the location of a pair of resource blocks to be hopped is fixed, although not completely symmetrical as shown in FIG. 6.

The X-PDCCH may be mapped to a resource block in resource block aggregation units 1 or 2. For example, suppose three UEs monitor X-PDCCH candidates. UE1 and UE2 have a resource block aggregation unit of 1 and UE3 has a resource block aggregation unit of 2. UE1 and UE2 recognize a pair of resource blocks as one X-PDCCH and perform monitoring, that is, decoding. On the other hand, UE3 recognizes two pairs of resource blocks as one X-PDCCH and performs monitoring. In fact, each UE performs blind decoding because it does not know exactly which index of the resource block the X-PDCCH for itself is mapped to.

When performing monitoring, the search order proceeds according to resource block aggregation units supported by the UE. Since both the UE and the base station know that resource block hopping is a fixed pattern, the UE can obtain X-PDCCH for itself by monitoring X-PDCCH candidates corresponding to the secondary control region.

8 is a diagram illustrating an example of a resource block hopping pattern according to another embodiment of the present invention.

Referring to FIG. 8, the total number of resource blocks allocated to the secondary control region is four and the number of clusters is four. That is, one cluster includes one resource block.

VRB_m is an index indicated in a resource block virtual or logical domain allocated to a secondary control region. The candidates of VRB_m for the X-PDCCH may be defined as shown in the following table according to the resource block aggregation unit.

Resource Block Aggregation Unit VRB_m candidate for X-PDCCH 2 {0}, {1}, {2}, {3}, {4}, {5} 4 {0, 1}, {2, 3} 8 {0, 1, 2, 3}, {4, 5, 6, 7}

Referring to Table 5, the base station transmits the X-PDCCH to a specific terminal according to the resource block aggregation unit set through the VRB_m index. In practice, however, the physical domain transmits data using the PRB_m index calculated by Equation 2. For example, when the resource block aggregation unit AL is 2, the VRB_m candidate indexes may be {0}, {1}, {2}, {3}, {4}, and {5}. Assume that VRB_m = 0 is allocated to UE1 and VRB_m = 1 is allocated to UE0. Substituting this in Equation 2, X-PDCCH for UE1 is mapped to PRB_m = 2 and X-PDCCH for UE0 is mapped to PRB_m = 3 as shown in FIG.

When viewed in units of resource block pairs, resource blocks located in the same frequency band in slot 0 and slot 1 form one resource block pair and are identified by the PRB_m index. Accordingly, resource block hopping has a pattern of hopping in units of RB pairs, unlike in FIGS. 6 and 7.

The resource block hopping pattern as described above may obtain a frequency diversity gain when the resource block aggregation unit is 2 or more. Resource block aggregation unit is 1 can be considered that the terminal is in a good channel environment. Therefore, even if the resource block hopping flag is on, the resource block hopping pattern shown in FIG. 8 may not be applied. In other words, when the resource block aggregation unit is 1, frequency scheduling gain can be obtained within a predetermined sub-control region, and in other resource block aggregation units, frequency diversity gain can be obtained by using resource block hopping. have.

9 is a diagram illustrating an example of a resource block hopping pattern according to another embodiment of the present invention.

Referring to FIG. 9, the total number of RBs allocated to the secondary control region is 8 (m = 0 to 7 in slot 0 and m ′ = 0 to 7 in slot 1), and the number of clusters is 4. That is, one cluster includes two resource blocks. The base station transmits the X-PDCCH to the terminal on the subframe based on resource block hopping. Resource block hopping is performed in units of a pair of resource blocks (m, m '), and a pair of resource blocks (m, m') may be coupled by the following equation.

Referring to Equation 3, m 'is the index of the resource block of the slot 1, m is the index of the resource block of the slot 0. If the index of the resource block in slot 0 is determined to be m, the index of the resource block in slot 1 paired with it is determined to be m 'by the above equation (3). Equation 3 uses a resource block as a basic unit. N is a value representing the resource allocated to the secondary control region in resource block units. s _offset is an offset value for adjusting the frequency of resource block m and the frequency of resource block m 'to be spaced apart by a predetermined interval. That is, the width of resource block hopping may be adjusted by s _offset . The base station may explicitly inform the terminal of the resource block hopping pattern using the cell specific parameter s _offset . The UE may monitor the X-PDCCH candidates in the sub-control region based on the resource block hopping pattern determined through Equation 3 and obtain an X-PDCCH for the UE.

As an example, s _offset may be defined as shown in the table below.

s _offset Offset indicator 1/2 000 -1/2 001 1/4 010 -1/4 011 1/8 100 -1/8 101 1/16 110 -1/16 111

Referring to Table 6, s _offset may be specified as any value in Table 6, which is informed by the base station to the terminal by a 3-bit offset indicator. For example, suppose that the base station transmits an offset indicator = 010 to the terminal. At this time, s _offset = 1/4. If N = 8 and the number of clusters = 4, then m '= (m + 2) mod N. Thus, resource block pairs (m, m ') = {(0,2), (1,3), (2,4), (3,5), (4,6), (5,7), (6 , 0), (7, 1)} can obtain the resource block hopping pattern as shown in FIG. The offset indicator may be included in higher layer signaling, for example, an RRC message, and transmitted from the base station to the terminal. Of course, the s _offset is not limited to only eight values defined in Table 6, but may be defined in various ways such as four, sixteen, thirty-two, and so forth. In addition, the base station may inform the _{k offset (= N · s offset} ) than the s _offset to the terminal.

As another example, s _offset may be limited in range depending on N and the number of clusters. For example, the range of s _offset may be limited by the following equation.

Referring to Equation 4, Nc is the number of clusters. s _start is a minimum value of s _offset and may be s _start ≦ s _offset ≦ 1. However, the range of s _offset may have a full range as 1 / N≤s _offset ≤1. The minimum width of resource block hopping is determined by s _start . By the s _offset limited by Equation 4, the resource block hopping pattern may be defined more flexibly than by the s _offset values defined in Table 6.

Hereinafter, a method in which a UE monitors X-PDCCH candidates in a secondary control region is described in detail.

10 is a flowchart illustrating an operation of a terminal according to an embodiment of the present invention.

Referring to FIG. 10, the terminal receives a cluster configuration from a base station (S1000). The cluster configuration may be transmitted to the terminal by higher layer signaling such as an RRC message. For example, the base station may include the cluster configuration in the RRC connection configuration message or the RRC connection reconfiguration message to transmit to the terminal. However, if the cluster configuration between the terminal and the base station is pre-provisioned, the base station does not need to separately transmit the cluster configuration to the terminal. In this case, step S1000 may be omitted. As an example, the cluster configuration may be defined as shown in Table 2 above.

The terminal receives a secondary control region activation indicator (SCR activation indicator) from the base station (S1005). The secondary control region activation indicator indicates 'activation' or 'deactivation'. In case of 'activation', the terminal monitors X-PDCCH candidates in the secondary control region. Do not perform monitoring of PDCCH candidates.

The terminal receives the cluster configuration parameters from the base station in a state of knowing the cluster configuration (S1010). The terminal may be an evolved terminal capable of scheduling the X-PDCCH. The cluster configuration parameter is information required for cluster configuration and includes a cluster number indicator.

The terminal receives the resource block hopping flag from the base station (S1015). If the resource block hopping flag is 'on', the UE monitors X-PDCCH candidates based on the resource block hopping pattern in the secondary control region. If the resource block hopping flag is 'off', the UE monitors the X-PDCCH candidates without resource block hopping in the secondary control region. The RB flag may be included in higher layer signaling, for example, an RRC message or a MAC message, transmitted by the base station to the terminal.

The UE monitors the X-PDCCH candidates in the sub control region of the subframe (S1020). The X-PDCCH is mapped to one, two, four or eight resource blocks in the sub control region according to the resource block aggregation unit. Here, the supported resource block aggregation units may vary according to system bandwidth as shown in Table 3. When the resource block aggregation unit is determined, the number of X-PDCCH candidates is also determined accordingly.

Table 7 is a table defining the number of X-PDCCH candidates set for each aggregation unit of a resource block according to an embodiment. This is the case when N = 16.

Resource Block Aggregation Unit Λ Number of X-PDCCH candidates M (Λ) One 6 2 6 4 2 8 2

Referring to Table 7, when the resource block aggregation unit Λ = 1, the number M (1) = 6 of X-PDCCH candidates. Accordingly, the UE monitors one pair of resource blocks for six RB pairs in each of two slots in the subframe. The monitoring is performed for each pair of resource blocks because the resource block aggregation unit Λ = 1. Since a pair of resource blocks are associated with a predefined resource block hopping pattern, the terminal performs monitoring based on a predefined resource block hopping pattern. The resource block aggregation unit Λ is an element that is UE-specifically determined. Therefore, the number of X-PDCCH candidates may be individually defined for each UE.

Table 8 is a table defining the number of X-PDCCH candidates set for each aggregation unit of a resource block according to another embodiment. This is the case when N = 32.

Resource Block Aggregation Unit Λ Number of X-PDCCH candidates M (Λ) One 12 2 12 4 4 8 4

Referring to Table 8, when the resource block aggregation unit Λ = 2, the number of X-PDCCH candidates M (2) = 12. Accordingly, the UE monitors a total of 12 RB pairs in each of two slots in a subframe by one pair of RB pairs.

As such, when the UE monitors X-PDCCH candidates for each resource block aggregation unit, a logical resource block (VRB) to which the X-PDCCH is mapped is determined by the following equation.

Referring to Equation 5, n _VRB ^{X - PDCCH} is a logical resource block index indicating a resource block mapped to the X-PDCCH in the logical domain, Λ is a resource block aggregation unit, k is a logical resource that the terminal starts monitoring As a block index, k = 0, 1, ..., M (Λ) -1. And i is the number of logical resource blocks to which one X-PDCCH is mapped, a parameter dependent on the resource block aggregation unit, i = 0, 1, ..., Λ-1.

11 is a view illustrating a monitoring method of a terminal according to an embodiment of the present invention. This is the case when the resource block aggregation unit is two.

Referring to FIG. 11, when the resource block aggregation unit Λ is 2 and the number of resource blocks N = 16 allocated to the sub-control area, when Λ = 2 is substituted in Table 7, M (2) = 6 and k = 0, 1, 2, 3, 4, 5 and i = 0, 1. Substituting this in Equation 5, an index of a logical resource block to be monitored by the UE is obtained.

First, when k = 0 and i = 0, n _VRB ^{X - PDCCH} = (2 占 0 + 0) mod 16 = 0. When k = 0 and i = 1, n _VRB ^X-PDCCH = (2 · 0 + 1) mod 16 = 1. That is, the terminal monitors the resource blocks having logical resource block indexes 0 and 1 starting with the resource block having logical resource block index 0 and as the resource block aggregation unit 2. At this time, resource block paired by resource block hopping is also monitored. For example, logical resource block index 0 in slot 0 and logical resource block index 0 in slot 1 are resource blocks paired (0,0), logical resource block index 1 in slot 0 and logical resource block index 1 in slot 1 When these resource blocks form a pair (1, 1), the terminal may monitor in the order of 0 (slot 0)-> 0 (slot 1)-> 1 (slot 0)-> 1 (slot 1). .

Next, when k = 1 and i = 0, n _VRB ^{X - PDCCH} = (2 占 +0) mod 16 = 2. When k = 1 and i = 1, n _VRB ^{X - PDCCH} = (2 占 +1) mod 16 = 3. That is, the terminal monitors the resource blocks having logical resource block indexes 2 and 3 starting with the resource block having logical resource block index 2 and as the resource block aggregation unit 2.

In this manner, when all of k = 5 and i = 1 are substituted into Equation 5, the UE monitors resource blocks up to n _VRB ^{X − PDCCH} = 11 as resource block aggregation unit 2.

n _VRB ^{X - PDCCH} may be mapped to a physical resource block index m by a certain rule or randomly. However, it is assumed that the terminal and the base station know all of the mapping relationship between the logical resource block index and the physical resource block index. For example, n _VRB ^{X - PDCCH} = f (m) and n ' _VRB ^{X - PDCCH} = f' (m '). That is, n _VRB ^{X - PDCCH} can be determined as a function of f () with m as a parameter, and n ' _VRB ^{X - PDCCH} can be determined as a function of f' () with m 'as a parameter. Accordingly, the UE monitors the X-PDCCH candidates after receiving the resource blocks by the physical resource block index, sorting them again according to the logical resource block index. However, in the present invention, it is assumed that the logical resource block index and the physical resource block index are the same. It is a ^{_{PDCCH = m, n 'VRB X}} -PDCCH = m' - for example, ^X n _VRB. However, this is for convenience of description only and does not limit the technical spirit of the invention.

When the physical resource block index m = n _VRB ^{X - PDCCH in} slot 0, the resource block index m 'in slot 1 is determined by Equation 1 or Equation 3 above. For example, when m 'is determined by Equation 1, (m, m') = {(0, 8), (1, 9), (2, 10), (3, 11), (4, 12), (5, 13), (6, 14), (7, 15), (8, 4), (9, 5), (10, 6), (11, 7) }to be. That is, when resource blocks (m, m ') form one resource block pair, the terminal performs blind decoding in the order of m->m'. That is, in FIG. 11, blind decoding is performed in the order of BD1->BD2->BD3->BD4->BD5-> BD6. Here, BD1, BD2, ... represent the order of blind decoding.

12 is a diagram illustrating a monitoring method of a terminal according to another example of the present invention. This is the case where the resource block aggregation unit is one.

Referring to FIG. 12, when the resource block aggregation unit Λ is 1 and the number of resource blocks N = 16 allocated to the sub-control area is substituted for Λ = 1 in Table 7, M (1) = 6 and k = 0, 1, 2, 3, 4, 5 and i = 0. Substituting this in Equation 5 provides a logical resource block index to be monitored by the terminal.

First, when k = 0 and i = 0, n _VRB ^{X - PDCCH} = (1 · 0 + 0) mod 16 = 0. That is, the terminal monitors only the resource blocks having the logical resource block index k = 0 as the resource block aggregation unit 1 starting from the resource block having the logical resource block index k = 0.

When k = 1 and i = 0, n _VRB ^{X - PDCCH} = (1 · 1 + 0) mod 16 = 1. That is, the terminal monitors only the resource block of the logical resource block index 1 as the resource block aggregation unit 1 starting from the resource block of the logical resource block index 1. At this time, resource block paired by resource block hopping is also monitored. For example, logical resource block index 0 in slot 0 and logical resource block index 0 in slot 1 form a resource block pair (0,0), and logical resource block index 1 in slot 0 and logical resource block index 1 in slot 1 If the resource block pair (1,1) is formed, the terminal may perform monitoring in the order of 0 (slot 0)-> 0 (slot 1)-> 1 (slot 0)-> 1 (slot 1).

Next, when k = 2 and i = 0, n _VRB ^{X − PDCCH} = (1 · 2 + 0) mod 16 = 2. The terminal monitors only the resource blocks having the logical resource block index k = 2 as the resource block aggregation unit 1, starting from the resource block having the logical resource block index k = 2.

When k = 3 and i = 0, n _VRB ^{X - PDCCH} = (1 占 +0) mod 16 = 3. The terminal monitors only the resource blocks having the logical resource block index k = 3 as the resource block aggregation unit 1, starting from the resource block having the logical resource block index k = 3.

In this way, if all of the equation 5 is substituted until k = 5, i = 0, the UE monitors the resource blocks up to n _VRB ^{X - PDCCH} = 5 as the resource block aggregation unit 1. n _VRB ^X-PDCCH is a logical index of a resource block, and may be mapped to a physical index m by a certain rule or randomly. However, it is assumed that the terminal and the base station know all of the mapping relationship between the logical resource block index and the physical index of the resource block. For example, n _VRB ^{X - PDCCH} = f (m) and n ' _VRB ^{X - PDCCH} = f' (m '). In other words n _VRB ^{X - PDCCH} is determined by the function of f () with m as parameters, and n ' _VRB ^{X - PDCCH} Can be determined as a function of f '() with m' as a parameter. Accordingly, the UE monitors the X-PDCCH candidates after receiving the physical resource blocks and sorting them again according to logical indexes. However, in the present invention, it is assumed that the logical index and the physical index of the resource block are the same. For example, n _VRB ^{X - PDCCH} = m and n ' _VRB ^{X - PDCCH} = m'. However, this is for convenience of description only and does not limit the technical spirit of the invention.

When the physical resource block index m = n _VRB ^{X - PDCCH in} slot 0, the physical resource block index m 'in slot 1 is determined by Equation 1 or Equation 3 above. For example, when m 'is determined by Equation 1, (m, m') = {(0, 8), (1, 9), (2, 10), (3, 11), (4, 12), (5, 13)}. That is, when resource blocks (m, m ') form one resource block pair, the terminal performs blind decoding in the order of m->m'. That is, in FIG. 12, blind decoding is performed in the order of BD1->BD2->BD3->BD4->BD5-> BD6.

13 is a flowchart illustrating an operation of a base station according to an embodiment of the present invention.

Referring to Figure 13, the base station transmits the cluster configuration to the terminal (S1300). The cluster configuration may be transmitted to the terminal by higher layer signaling such as an RRC message. For example, the base station may include the cluster configuration in the RRC connection configuration message or the RRC connection reconfiguration message to transmit to the terminal. However, if the cluster configuration between the terminal and the base station is pre-provisioned, the base station does not need to separately transmit the cluster configuration to the terminal. In this case, step S1300 may be omitted. As an example, the cluster configuration may be defined as shown in Table 2 above.

The base station transmits the secondary control region activation indicator to the terminal (S1305). The secondary control region activation indicator indicates 'activation' or 'deactivation'. In case of 'activation', the terminal monitors X-PDCCH candidates in the secondary control region. Do not perform monitoring of PDCCH candidates.

The base station transmits the cluster configuration parameter to the terminal (S1310). The terminal may be an evolved terminal capable of scheduling the X-PDCCH. The cluster configuration parameter is information required for cluster configuration and includes a cluster number indicator.

The base station transmits the resource block hopping flag to the terminal (S1315). If the resource block hopping flag is 'on', the UE monitors X-PDCCH candidates based on the resource block hopping pattern in the secondary control region. If the resource block hopping flag is 'off', the UE monitors the X-PDCCH candidates without resource block hopping in the secondary control region. The RB flag may be included in higher layer signaling, for example, an RRC message or a MAC message, transmitted by the base station to the terminal.

The base station maps the X-PDCCH for the terminal to the resource block in the secondary control region based on the resource block hopping of a specific pattern (S1320). The process of mapping the X-PDCCH to the resource block includes, for example, mapping to at least one resource block pair by resource block hopping as described with reference to FIGS. 6 to 9, 11, and 12. Here, the number of resource block pairs is equal to the resource block aggregation unit. The base station transmits the mapped X-PDCCH to the terminal (S1325).

14 is a block diagram of a base station and a terminal according to an embodiment of the present invention.

Referring to FIG. 14, the terminal 1400 includes a receiver 1405 and a terminal processor 1410. The base station 1450 includes a base station processor 1455 and a transmitter 1460.

The base station processor 1455 generates a cluster configuration, a secondary control region activation indicator, a cluster configuration parameter, and a resource block hopping flag.

The cluster configuration may be transmitted to the terminal 1400 by higher layer signaling such as an RRC message. For example, the base station may include the cluster configuration in the RRC connection configuration message or the RRC connection reconfiguration message to transmit to the terminal 1400. However, if the cluster configuration is previously prescribed between the terminal 1400 and the base station, the base station does not need to separately transmit the cluster configuration to the terminal 1400. As an example, the cluster configuration may be defined as shown in Table 2 above.

The secondary control region activation indicator indicates 'activation' or 'deactivation'. When the secondary control region activation indicator indicates 'activation', the terminal 1400 monitors X-PDCCH candidates in the secondary control region, and when the secondary control region indicates 'deactivation', the terminal 1400 indicates X- in the secondary control region. Do not perform monitoring of PDCCH candidates.

The cluster configuration parameter is information required for cluster configuration and includes a cluster number indicator.

Resource block hopping flag indicates on / off of resource block hopping. For example, the resource block hopping flag is 1 bit and '1' may mean 'on' of resource block hopping and '0' may mean 'off' of resource block hopping. The RB flag may be included in higher layer signaling, for example, an RRC message or a MAC message, transmitted by the base station to the terminal 1400. If the resource block hopping flag is 'on', the UE 1400 monitors X-PDCCH candidates based on the resource block hopping pattern in the secondary control region. If the resource block hopping flag is 'off', the UE 1400 monitors X-PDCCH candidates without resource block hopping in the secondary control region. The RB flag may be included in higher layer signaling, for example, an RRC message or a MAC message, transmitted by the base station to the terminal 1400.

The transmitter 1460 transmits the cluster configuration, the secondary control region activation indicator, the cluster configuration parameter, and the resource block hopping flag to the terminal 1400. In addition, the transmitter 1460 configures a physical layer channel and transmits it to the terminal 1400. For example, the physical layer channel includes a PDCCH mapped to the primary control region, an X-PDCCH mapped to the secondary control region, and a PDSCH mapped to the data region. In particular, the transmitter 1460 maps the X-PDCCH for the UE 1400 to the resource block in the sub-control area based on the resource block hopping of a specific pattern. The process of the transmitter 1460 mapping the X-PDCCH to the resource block is performed by mapping the at least one resource block pair by resource block hopping as described with reference to FIGS. 6 to 9, 11, and 12, for example. The process of becoming. Here, the number of resource block pairs is equal to the resource block aggregation unit. The transmitter 1460 transmits the mapped X-PDCCH to the terminal 1400.

The terminal 1400 includes a receiver 1405 and a terminal processor 1410.

The receiver 1405 receives the cluster configuration, the secondary control region activation indicator, the cluster configuration parameter, and the resource block hopping flag from the base station 1450. The terminal processor 1410 specifies resource blocks allocated to the secondary control region based on the cluster configuration and the cluster configuration parameter. The terminal processor 1410 checks whether the X-PDCCH is transmitted based on the indication of the secondary control region activation indicator. In addition, the terminal processor 1410 controls the receiver 1405 to receive the X-PDCCH in a specific resource block hopping pattern based on the indication of the resource block hopping flag.

In addition, the reception unit 1405 receives a physical layer channel including a PDCCH mapped to the primary control region, an X-PDCCH mapped to the secondary control region, and a PDSCH mapped to the data region, from the base station 1450. At this time, the receiving unit 1405 may monitor the X-PDCCH candidates in the sub-control region with a specific resource block hopping pattern under the control of the terminal processor 1410. For example, the terminal processor 1410 provides the receiver 1405 with information about the number N of resource blocks allocated to the sub control region from the system bandwidth and the resource block aggregation unit Λ. The receiver 1405 determines the blind decoding order by substituting N, Λ, k, and i into Equation 5, and monitors the X-PDCCH candidates according to the determined blind decoding order.

All of the above functions may be performed by a processor such as a microprocessor, a controller, a microcontroller, an application specific integrated circuit (ASIC), or the like according to software or program code coded to perform the function. The design, development and implementation of the code will be apparent to those skilled in the art based on the description of the present invention.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention. You will understand. Therefore, it is intended that the present invention covers all embodiments falling within the scope of the following claims, rather than being limited to the above-described embodiments.

Claims (17)

A method of transmitting a control channel by a base station in a subframe including a main control region and a data region,
Allocating the data area to a sub-control area including a cluster consisting of one or more adjacent resource blocks at a specific location;
Transmitting a cluster number indicator indicating the number of clusters to a terminal;
Mapping a physical downlink control channel to resource blocks specified by the number of clusters; And
And transmitting the mapped physical downlink control channel to the terminal. The method of claim 1,
And transmitting a cluster configuration, which is information about resource blocks specified by the number of clusters and the number of clusters, to the terminal. The method of claim 1,
And the physical downlink control channel is mapped to resource blocks specified by the number of clusters by resource block hopping. The method of claim 3, wherein
And transmitting the resource block hopping indicator indicating on / off of the resource block hopping to the terminal. The method of claim 3, wherein the resource block hopping,
And mapping the physical downlink control channel to resource blocks of different frequency bands in each of two slots constituting the subframe on a time axis. A base station transmitting a control channel in a subframe including a main control region and a data region,
A processor for allocating the data area to a sub-control area including a cluster composed of one or more adjacent resource blocks at a specific location, and generating a cluster number indicator indicating the number of clusters; And
And a transmitter for mapping a physical downlink control channel to resource blocks specified by the number of clusters, and transmitting the mapped physical downlink control channel to the terminal. The method of claim 6, wherein the processor generates a cluster configuration that is information about resource blocks specified by the number of clusters and the number of clusters,
The transmitter is characterized in that for transmitting the cluster configuration to the terminal. The method of claim 6, wherein the transmission unit,
And mapping the physical downlink control channel to resource blocks specified by the number of clusters by resource block hopping. The method of claim 8, wherein the processor generates a resource block hopping indicator indicating on / off of the resource block hopping,
The transmitter, the base station, characterized in that for transmitting the resource block hopping indicator to the terminal. 9. The method of claim 8, wherein the frequency hopping is
And the physical downlink control channel is mapped to resource blocks of different frequency bands in each of two slots constituting the subframe on a time axis. In a method of receiving a control channel by a terminal in a subframe including a main control region and a data region,
Receiving from the base station a cluster number indicator indicating the number of clusters consisting of one or more adjacent resource blocks of a specific location in the data area; And
And decoding the candidates of the physical downlink control channel mapped to the resource blocks in the sub-control region specified by the number of clusters by a predetermined resource block aggregation unit. The method of claim 11,
The number of resource blocks in the sub-control area is determined by the system bandwidth for the terminal, the method of receiving a control channel. The method of claim 11,
And candidates of the physical downlink control channel are mapped to resource blocks in the sub-control area by resource block hopping. The method of claim 13, wherein the resource block hopping,
And mapping the physical downlink control channel to resource blocks of different frequency bands in each of two slots constituting the subframe on a time axis. A terminal for receiving a control channel in a subframe including a main control region and a data region,
Receiving a cluster number indicator indicating a number of clusters composed of one or more adjacent resource blocks of a specific position in the data area from a base station and mapping the resource blocks in a sub-control area specified by the number of clusters; A receiver which decodes candidates of a physical downlink control channel by a predetermined resource block aggregation unit; And
And a processor for providing the receiver with information about the number of resource blocks in the sub-control region determined by the system bandwidth of the terminal and the resource block aggregation unit. The method of claim 15,
The receiving unit, characterized in that for decoding the candidates of the physical downlink control channel by resource block hopping. The method of claim 16, wherein the resource block hopping,
And the physical downlink control channel is mapped to resource blocks of different frequency bands in each of two slots constituting the subframe on a time axis.

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