KR20140136736A - Apparatus and method for transmitting and receiving control channel in wireless communication system based on nct - Google Patents

Abstract

The present invention relates to a transmission apparatus, a transmission method, a reception apparatus, and a reception method of a control channel in a wireless communication system based on NCT.
In this specification, the present invention is characterized in that, in the common search space on the NCT, a control unit is provided to control the monitoring unit to monitor the EPCCH candidate according to an aggregation unit defined in any one of the cases where the receiving unit monitors up to six EPDCCH candidates, And a data processing unit for analyzing the DCI obtained by monitoring the EPDCCH candidate and performing an operation indicated by the DCI.

Description

Technical Field [0001] The present invention relates to a transmission apparatus, a transmission method, a receiving apparatus, and a reception method of a control channel in a wireless communication system based on NCT,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to wireless communication, and more particularly, to a transmission apparatus, a transmission method, a reception apparatus, and a reception method of a control channel in a wireless communication system based on NCT.

Component carriers (CC) used in a conventional multiple component carrier system emphasize the versatility of the physical layer, and control area redundancy and common signal overhead still exist. Therefore, it is emphasized that there is an unnecessary loss in terms of spectral efficiency because resources for data signals are reduced. Accordingly, in order to efficiently operate the multi-carrier system, it is required to introduce a new carrier type (NCT: New Carrier Type) constituting a multi-carrier system. In the NCT, a reference signal (RS) for a downlink control channel or a channel estimation is provided within a range in which there is no degradation or minimization of performance as compared with a legacy carrier type (LCT) Can be removed or reduced. This is to obtain maximum data transmission efficiency. An existing carrier wave is called a backward compatible carrier type (BCCT) by distinguishing it from an NCT.

The NCT may include a non-standalone NCT and a standalone NCT. A non-standalone NCT is an NCT that can not exist in a single cell form and can exist in the form of a secondary serving cell (SCell) when a primary serving cell (PCell) exists. On the other hand, a standalone NCT is an NCT that can exist in a single cell form. For example, a standalone NCT can exist in the form of a main serving cell. In a standalone NCT and a non-standalone NCT, a cell-specific RS (CRS) may not be transmitted. Accordingly, a control channel based on CRS, which is a conventional physical downlink control channel (PDCCH), a physical HARQ indicator channel (PHICH), a physical control format indicator channel : PCFICH) may be removed or replaced with another type of channel.

In the stand-alone NCT, an extended physical downlink control channel (EPDCCH) may be used for the purpose of expanding the capacity of the existing PDCCH. EPDCCH may also be referred to as an enhanced physical downlink control channel, which until now could only be transmitted in a UE specific search space (USS). On the other hand, the PDCCH transmits common downlink control information (DCI) such as system information, paging information, and transmission power control information on a common search space (CSS) as well as a UE specific search space . However, the PDCCH is coherently detected in the CRS and the EPDCCH is coherently detected in the demodulation reference signal (DMRS). In this case, demodulation of the EPDCCH and the PDSCH in the standalone NCT can be performed based on the DMRS.

If there is a common search space or UE specific search space (USS) for the EPDCCH in the NCT, the UE can perform monitoring of the EPDCCH received in the common search space or the UE-specific search space. Monitoring may also be referred to as blind decoding. In order for the UE to perform EPDCCH monitoring, an amount of an enhanced control channel element (ECCE) constituting a common search space or a UE-specific search space, an aggregation level of an ECCE, The number of EPDCCH candidates according to a predetermined rule or a combination thereof must be defined according to a certain rule. This is because the monitoring frequency of the terminal can be determined accordingly.

Therefore, a method for monitoring EPDCCH in a wireless communication system based on NCT, a terminal performing the EPDCCH, a method for transmitting or allocating the EPDCCH, and a base station performing the EPDCCH are required.

SUMMARY OF THE INVENTION The present invention provides a control channel transmission apparatus, a transmission method, a reception apparatus, and a reception method in a wireless communication system based on NCT.

According to an aspect of the present invention, there is provided a terminal for receiving a control channel in a NCT (New Carrier Type) based wireless communication system. The UE includes a receiving unit for monitoring up to six enhanced physical downlink control channel (EPDCCH) candidates in a common search space on the NCT, a case in which the receiving unit is classified according to an EPDCCH allocation rule, a monitoring controller for monitoring the EPCCH candidate according to an aggregation level defined in any one of the cases, and analyzing downlink control information (DCI) obtained by monitoring the EPDCCH candidate, And a data processing unit for performing operations indicated by the DCI.

The EPDCCH allocation rule may include a rule for classifying the cases based on the number of ECCEs (Enhanced Control Channel Elements) in one PRB (physical resource block) pair.

According to another aspect of the present invention, there is provided a method of receiving a control channel by a terminal in a new carrier type (NCT) based wireless communication system. The method includes monitoring a maximum of six enhanced physical downlink control channel (EPDCCH) candidates in a common search space on the NCT, performing a DCI downlink control information, and performing an operation indicated by the DCI.

The number of EPDCCH candidates is determined according to an aggregation level defined in any one of cases classified according to an EPDCCH allocation rule. The EPDCCH allocation rule includes one physical resource block (PRB) And rules for classifying the cases based on the number of ECCEs (enhanced control channel elements) in the pair.

According to another aspect of the present invention, there is provided a base station for transmitting a control channel in a NCT (New Carrier Type) based wireless communication system. The base station generates downlink control information (DCI), adds a CRC (cyclic redundancy check) for error detection to the DCI, masks an identifier to the CRC, and performs channel coding on the DCI An EPDCCH for mapping the modulation symbols to an EPDCCH on a common search space on the NCT based on an aggregation unit according to an EPDCCH allocation rule, a data processing unit for generating encoded data by modulating the coded data, And a transmitter for transmitting the EPDCCH to the UE.

Up to six EPDCCH candidates are mapped on the common search space and the number of EPDCCH candidates is determined according to an aggregation level defined in any one of cases classified according to the EPDCCH allocation rule, The EPDCCH allocation rule may include a rule for classifying the cases based on the number of ECCEs (Enhanced Control Channel Elements) in one PRB (physical resource block) pair.

According to another aspect of the present invention, there is provided a method of transmitting a control channel by a base station in a new carrier type (NCT) based wireless communication system. The method includes generating downlink control information (DCI), adding a cyclic redundancy check (CRC) for error detection to the DCI, masking an identifier in the CRC, , Generating modulation symbols by modulating the encoded data, mapping the modulation symbols to the EPDCCH on the common search space on the NCT based on the aggregation unit according to the EPDCCH allocation rule And transmitting the EPDCCH to a terminal.

Up to six EPDCCH candidates are mapped on the common search space and the number of EPDCCH candidates is determined according to an aggregation level defined in any one of cases classified according to the EPDCCH allocation rule, The EPDCCH allocation rule may include a rule for classifying the cases based on the number of ECCEs (Enhanced Control Channel Elements) in one PRB (physical resource block) pair.

The base station can effectively support the EPDCCH transmission on the NCT, and the terminal can efficiently perform the EPDCCH monitoring.

1A is a block diagram illustrating a wireless communication system.
1B is a diagram showing a transmission structure of PBCH, PSS and SSS on the FDD.
2A-2E illustrate examples of PRB pairs according to one embodiment.
Figure 3 is an illustration of a local transmission.
Figure 4 is an example of a distributed transmission.
5 is a table showing the allocation of EPDCCH candidates monitored by the UE according to an example of the present invention.
FIG. 6 is a table showing assignments of EPDCCH candidates monitored by a UE according to another example of the present invention.
7 is a table showing assignments of EPDCCH candidates monitored by a UE according to another example of the present invention.
8 is a table showing the allocation of EPDCCH candidates monitored by the UE according to another example of the present invention.
9 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention.
10 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention.
11 is a table showing the allocation of EPDCCH candidates monitored by the UE according to another example of the present invention.
12 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention.
FIG. 13 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention.
Figure 14 is a table showing assignments of EPDCCH candidates monitored by a UE according to another example of the present invention.
15 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention.
16 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention.
17 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention.
18 is a table showing assignments of EPDCCH candidates monitored by a UE according to another example of the present invention.
FIG. 19 is an example of comparing the coding rate of the conventional PDCCH, the coding rate of EPDCCH Case 1, and the coding rate of EPDCCH Case 2 with respect to L = 1, 2, 4, 8, 16,
20 is a table showing assignments of EPDCCH candidates monitored by a UE according to another example of the present invention.
FIG. 21 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention.
22 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention.
FIG. 23 is an example of comparing the coding rate of the conventional PDCCH, the coding rate of EPDCCH Case 1, the coding rate of EPDCCH Case 2, and the coding rate of EPDCCH Case 3 with respect to L = 1, 2, 4, 8, 16 and 32.
24A is a table showing assignments of EPDCCH candidates monitored by a UE according to another example of the present invention.
FIG. 24B is a table showing allocation of EPDCCH candidates monitored by the UE according to another example of the present invention. FIG.
FIG. 24C is a table showing assignments of EPDCCH candidates monitored by a UE according to another example of the present invention. FIG.
25 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention.
26 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention.
FIG. 27 is a flowchart illustrating a process in which an EPDCCH is transmitted and received between a terminal and a base station according to an example of the present invention.
28 is a block diagram illustrating a terminal and a base station according to an example of the present invention.

Hereinafter, some embodiments will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference numerals whenever possible, even if 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.

The present invention will be described in the context of a communication network. A task in a communication network may be performed in a process of controlling a network and transmitting data in a system (e.g., a base station) that manages the communication network, Work can be done.

According to one embodiment of the present invention, 'transmitting a control channel' can be interpreted as meaning that control information is transmitted through a specific channel. Here, the control channel includes, for example, a Physical Downlink Control Channel (PDCCH), an Extended PDCCH (Extended-PDCCH), or a Physical Uplink Control Channel (PUCCH) .

1 is a block diagram illustrating a wireless communication system. This may be a network structure of an Evolved-Universal Mobile Telecommunications System (E-UMTS). The E-UMTS system may be called LTE (Long Term Evolution) or LTE-A (advanced) system. Wireless communication systems are widely deployed to provide various communication services such as voice, packet data, and the like.

On the other hand, there is no limitation on a multiple access technique applied to a wireless communication system. (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.

Here, TDD (Time Division Duplex) scheme in which uplink and downlink transmission are transmitted using different time periods or FDD (Frequency Division Duplex) scheme in which they are transmitted using different frequencies may be used .

Referring to FIG. 1, an E-UTRAN includes at least one base station (BS) 20 that provides a control plane and a user plane to a UE. A user equipment (UE) 10 may be fixed or mobile and may be a mobile station, an AMS (advanced MS), a user terminal (UT), a subscriber station (SS) It can be called a term.

The base station 20 generally refers to a point of communication with the terminal 10 and includes an evolved-NodeB (eNodeB), a base transceiver system (BTS), an access point, a femto-eNB, a pico-eNB, a home eNB, a relay, and so forth. The base station 20 may provide at least one cell to the terminal. The cell may mean a geographical area where the base station 20 provides communication services, or may refer to a specific frequency band. A cell may denote a downlink frequency resource and an uplink frequency resource. Or a cell may mean a combination of a downlink frequency resource and an optional uplink frequency resource. Also, in general, when a carrier aggregation (CA) is not considered, uplink and downlink frequency resources always exist in one cell.

An interface for transmitting user traffic or control traffic may be used between the base stations 20. The source BS 21 refers to a base station for which a radio bearer is currently set with the UE 10 and a target BS 22 transmits a radio bearer to the source BS 21, Means a base station to perform a handover in order to set up a radio bearer.

The base stations 20 can be connected to each other via the X2 interface, which is used to exchange messages between the base stations 20. [ The base station 20 is connected to an Evolved Packet System (EPS), more specifically a Mobility Management Entity (MME) / S-GW (Serving Gateway) 30 via an S1 interface. S1 interface supports many-to-many-relations between the base station 20 and the MME / S-GW 30. The PDN-GW 40 is used to provide packet data service to the MME / S-GW 30. The PDN-GW 40 is changed depending on the purpose of communication or the service, and the PDN-GW 40 supporting the specific service can be found using APN (Access Point Name) information.

Hereinafter, a new carrier type (NCT) applied to this specification will be described in detail. When the terminal assembles a carrier wave, for example, it can aggregate an existing carrier type (set as a main serving cell) and an NCT (NCT in this case is non-stand-alone). The NCT may not transmit signals such as PBCH, PDCCH, PHICH, and PCFICH, for example. The NCT may not support transmission modes (TM) 1 to 8. That is, TM9 or TM10 can be supported in NCT. In the NCT, a PDSCH transmission method having up to 8 layers can be supported, and DCI formats 1A and 2C / 2D can be used for PDSCH transmission on the NCT. The DCI formats 1A and / or 2C / 2D may be indicated via ePDCCH (enhanced PDCCH) on the NCT and may be indicated via cross-carrier scheduling from the LCT. Since the TM9 or TM10 may be supported in the NCT, a CSI reference signal RS for supporting channel state information (CSI) feedback may be supported on the NCT.

Specifically, an NCT may include a non-standalone NCT, a standalone NCT, and an NCT with a dormant mode.

First, a non-standalone NCT is an NCT that can not exist in a single cell form and can exist in the form of a secondary serving cell if there is a main serving cell. For example, when a legacy carrier type (LCT) is set as the main serving cell in a terminal in which CA is set, non-standalone NCT secondary serving cells can be clustered together.

A non-standalone NCT can be divided into a synchronized NCT and an asynchronized NCT.

A synchronous NCT refers to an NCT operating with reference to the synchronization of another carrier (e.g., a legacy carrier). In other words, the synchronous NCT may be synchronized with other carriers in terms of time and frequency to indicate a case where a separate synchronization procedure is not required in the terminal. The synchronous NCT may not transmit PSS, SSS and CRS (and TRS, as described below). This allows overhead reduction of the common RS and PSS / SSS. In the synchronous NCT, there may be advantages such as interference mitigation, energy saving, and imporved spectral efficacy for the adjacent cell due to the reduction of the overhead, and due to the reduction of the public RSs A network provider can more flexibly utilize frequency bandwidth.

The asynchronous NCT means an NCT that can operate independently by acquiring independent synchronization regardless of other carriers (for example, a main serving cell in the form of a legacy carrier). For the asynchronous NCT, the PSS and the SSS transmit the same as the legacy carrier type, but the CRS transmission frequency and transmission bandwidth may be small. For example, in an asynchronous NCT, a CRS may be transmitted with a period of time, in which case the CRS may be referred to as a reduced CRS (reduced CRS) or a TRS (Tracking RS) since it can only be used for synchronization purposes. Specifically, for example, the TRS can be transmitted on the basis of the CRS antenna port 0 with a 5 ms period on the time axis. Also, the TRS can be transmitted in the entire system bandwidth on the frequency axis, or only in some system bandwidths.

Second, the standalone NCT is an NCT that can exist in a single cell form. For example, a standalone NCT can exist in the form of a main serving cell. Standalone NCTs Like the non-standalone NCTs, the CRS can be removed, but the TRS mentioned above can be transmitted. Accordingly, the existing PDCCH, PHICH, and PCFICH, which are CRS-based control channels, can be removed or replaced with other types of channels. Demodulation of EPDCCH and PDSCH in a standalone NCT can be performed based on DMRS.

Third, the dormant NCT means an NCT that can enter the on and off states as the case may be. For example, the dormant NCT may be operated in the on (active), off (dormant) mode depending on the traffic state. That is, the base station can turn off power to the dormant NCT cell according to the traffic requirements of the terminal, thereby saving energy and reducing cell interference. When the dormant NCT is in the sleep mode, the base station can transmit only the cell identification signal of a longer period (for example, PSS / SSS) to the UE without transmitting the CRS to transmit the minimum signal to the UE. In this case, the cell identification signal may be called a DS (Discovery Signal).

According to the present specification, an NCT supporting a common search space (CSS) based on DMRS can be provided. In particular, the NCT supporting the common search space may be a standalone NCT or a non-standalone NCT. Here, a specific control channel is mapped to a common search space based on the DMRS, and this particular control channel can be referred to as EPDCCH. For example, the EPDCCH may be transmitted on a public search space of a standalone NCT or a non-standalone NCT.

In the following embodiments, control is carried out to carry common downlink control information (DCI) such as system information, paging information, random access information, MBMS control information, and transmission power control information in a common search space based on the DMRS. Channel is called a common EPDCCH, and a control channel for carrying downlink control information in a UE-specific search space is called a UE-specific EPDCCH. The simple EPDCCH includes both the common EPDCCH and the UE-specific EPDCCH.

1B is a diagram showing a transmission structure of PBCH, PSS and SSS in the FDD.

Referring to FIG. 1B, the UE-specific EPDCCH is not transmitted to the 6PRB pair in the center where the PBCH and the PSS / SSS are transmitted. The PBCH is transmitted on the first four OFDM symbols in the second slot of FDD and TDD subframe # 0. In the FDD, the PSS and the SSS are transmitted on the last two OFDM symbols of the first slot in subframes # 0 and # 5. On the other hand, in TDD, unlike FDD, SSS is transmitted on the last OFDM symbol of subframes # 0 and # 5, and PSS is transmitted on the third OFDM symbol of subframes # 1 and # 6.

A method for monitoring an EPDCCH according to an embodiment of the present invention and a terminal, a method for transmitting or allocating an EPDCCH, and a base station can be equally applied to a common EPDCCH and a UE-specific EPDCCH.

The EPDCCH assignment is now described.

Each terminal may be configured with K EPDCCH sets (e.g., 1? K? 2), and one EPDCCH set p is defined as a group including N _RB ^Xp PRB pairs. The EPDCCH set may also be referred to as the EPDCCH PRB set.

One pair of PRBs may be defined as two slots in the time axis and a resource region corresponding to one RB in the frequency axis. Or one PRB pair may mean an area corresponding to 12 resource elements (REs) having a bandwidth of, for example, 180 KHz and a 15 KHz subcarrier spacing in a normal subframe. The PRB pairs may be overlapped, partially overlapped, or may not overlap at all between different EPDCCH sets.

The EPDCCH is transmitted using one or more enhanced control channel elements (ECCEs). Here, ECCE is a basic unit through which EPDCCH is transmitted. For example, EPDCCH can be mapped to one ECCE, two ECCEs, four ECCEs, eight ECCEs, 16 ECCEs, and 32 ECCEs. The downlink control information (DCI) is transmitted in a manner of aggregating one ECCE or a plurality of ECCEs.

An ECCE may include a plurality of Enhanced Resource Element Groups (EREGs). For example, an ECCE may include four EREGs or eight EREGs. Here, one EREG is a group composed of at least one resource element (RE).

The number of EREGs to be included in the ECCE is determined based on a subframe type (for example, a normal subframe or a special subframe) according to the TDD (Time Division Duplex) DL-UL setting and a CP type You can depend on it. For example, in a normal CP (cyclic prefix) and a normal subframe, or in a normal CP and special subframe settings 3, 4, and 8, the ECCE includes four EREGs, An ECCE may contain eight EREGs in 2, 6, 7, 8, or extended CP and normal subframes, or an extended CP and special subframe settings 1, 2, 3, 5, . In the TDD system, each subframe may be composed of a downlink subframe, an uplink subframe, and a special subframe. A subframe other than a special subframe is called a normal subframe by distinguishing it from a special subframe. For example, a normal subframe includes a downlink subframe in a TDD system, an uplink subframe, and a subframe in an FDD system.

The special subframe includes three fields such as DwPTS, GP, and UpPTS. Depending on the length of each field, the TDD configuration of a particular subframe may be defined as a maximum of nine according to the CP type as shown in Table 1. [

TDD configuration of special subframe Normal CP Extended CP DwPTS UpPTS DwPTS UpPTS In the uplink, the normal CP In the uplink, the extended CP In the uplink, the normal CP In the uplink, the extended CP 0 6592Ts 2192Ts 2560Ts 7680Ts 2192Ts 2560Ts One 19760Ts 20480Ts 2 21952Ts 23040Ts 3 24144Ts 25600Ts 4 26336Ts 7680Ts 4384Ts 5120Ts 5 6592Ts 4384Ts 5120Ts 20480Ts 6 19760Ts 23040Ts 7 21952Ts 12800Ts 8 24144Ts - - - 9 13168Ts - - -

Referring to Table 1, the TDD configuration of the special subframe may be different depending on whether the CP type is a normal CP or an extended CP. Here, Ts is a unit time indicating the size of the field on the time axis of the frame, and may be, for example, Ts = 1 / (15000 * 2048) sec.

2A-2E illustrate examples of PRB pairs according to one embodiment.

Referring to FIGS. 2A to 2E, sixteen EREGs are included in one PRB pair. In other words, all EREGs belonging to one PRB pair can be represented by indices 0 to 15, and 0, 1, 2, ..., 15 denoted in each resource element in the drawing represent the index of EREG to which each resource element belongs. In the first OFDM symbol (l = 0) of the time axis, the indexes 0, 1, 2, ..., 15 of the EREG can be assigned to each resource element sequentially from the first, that is, the lower frequency subcarrier at the top of the frequency axis.

On the other hand, the resource element indicated by R is used for transmission of the DM-RS. The arrangement and number of DM-RSs may be different in each embodiment. For example, since 24 resource elements are used for the DM-RS in FIG. 2A, 16 EREGs are generated from 144 resource elements excluding 24 resource elements. In this case, one EREG may contain nine resource elements. However, in addition to the DM-RS, one CSI-RS or CRS or an existing control region (i.e., one or more OFDM symbols of a subframe in which the existing PDCCH is transmitted) may be arranged in one PRB pair. In this case, the number of available resource elements (available REs) is reduced, and the number of resource elements included in one EREG can be reduced. Also, since the number of resource elements available varies depending on the CP type, the number of resource elements included in one EREG can also be changed. Also, since the number of available resource elements varies depending on the type of subframe, the number of resource elements included in one EREG can also be changed.

In an example, FIG. 2A shows that sixteen EREGs are formed from the remaining 144 resource elements excluding the 24 resource elements for the DM-RS in the PRB pair composed of the normal sub-frame and the normal CP.

In another example, FIG. 2B shows that sixteen EREGs are formed from the remaining 128 resource elements excluding the 16 resource elements for the DM-RS among the total 144 resource elements in the PRB pair composed of the normal sub-frame and the extended CP. In this case, 1 EREG contains 8 resource elements.

In another example, FIG. 2C shows a case where in a PRB pair composed of special subframes 1 (9 OFDM symbols), 2 (10 OFDM symbols), 6 (9 OFDM symbols) In the configurations 1 and 6 (Embodiment A), 16 EREGs are formed from the remaining 84 resource elements excluding the 24 resource elements for the DM-RS among 108 resource elements available in the downlink, and special subframe configurations 2 and 7 (Embodiment B) shows that sixteen EREGs are formed from the remaining 96 resource elements excluding the 24 resource elements for the DM-RS among the 120 available resource elements in the downlink.

In another example, FIG. 2D shows that in a PRB pair composed of special subframe configurations 3 (11 OFDM symbols), 4 (12 OFDM symbols), 8 (11 OFDM symbols) In the configurations 3 and 8 (Embodiment A), 16 EREGs are formed from the remaining 108 resource elements excluding the 24 resource elements for the DM-RS among 132 resource elements available in the downlink, and a special subframe configuration 4 In the example B), 16 EREGs are formed from the remaining 120 resource elements excluding the 24 resource elements for the DM-RS among the 144 available resource elements in the downlink, and in the special subframe structure 9 (not shown) Indicates that 16 EREGs are formed from 60 resource elements except for 12 DM-RS resource elements out of 72 available resource elements.

As another example, FIG. 2E shows a configuration of a special subframe consisting of 8 OFDM symbols, 2 OFDM symbols, 3 OFDM symbols, 5 OFDM symbols, 6 OFDM symbols, In the PRB pair, sixteen EREGs are formed from the remaining 88 resource elements excluding the eight resource elements for the DM-RS among the 96 available resource elements in the downlink in the special subframe configurations 1 and 5 (Embodiment A) And 16 EREGs are formed from the remaining 100 resource elements excluding the 8 resource elements for the DM-RS among the 108 resource elements available in the downlink in the special subframe configurations 2 and 6 (Embodiment B) And in the special subframe structure 3 (not shown), 16 EREGs are formed from the remaining 112 resource elements excluding the DM-RS resource elements out of 120 available resource elements in the downlink.

Thus, although the number of resource elements included in the EREG may depend on the type of the reference signal, the CP type, and the subframe type, the number 16 of EREG included in one PRB pair may be fixed.

As described above, one ECCE can be defined as a group of EREGs. That is, one ECCE may include one or more EREGs. For example, as shown in Table 2, the number of EREGs included in each ECCE can be defined.

Normal CP Expanded CP The normal subframe Special subframe configurations 3,4,8 Special subframe configuration 1,2,6,7,9 The normal subframe Special subframe structure 1,2,3,5,6 4 8

Referring to Table 2, N _ECCE ^{EREG, which} is the number of EREGs constituting one ECCE, is defined according to the type and CP type of each subframe. For example, in a PRB pair consisting of a normal CP and a normal subframe or a normal CP and a special subframe configuration 3, 4, and 8, N _ECCE ^EREG is 4, and an extended CP and a normal subframe or a normal CP and a special subframe configuration 1 , 2, 6, 7, 9, or 8, where N _ECCE ^EREG is 8 in the PRB pair consisting of extended CPs and special subframe configurations 1, On the other hand, the number of ^ECCEs N _RB ^ECCE per PRB pair can be determined through N _ECCE ^EREG . Where N _RB ^ECCE = 16 / N _ECCE ^EREG . N _{ECCE When} ^EREG = 4, the number of ^ECCEs included in one PRB pair is N _RB ^ECCE = ^16/4 = 4. When N _ECCE ^EREG = 8, the number of ^ECCEs included in one PRB pair is N _RB ^ECCE = ^16/8 = 2.

The index (i.e., position) of the EREGs belonging to the ECCE can be defined by a certain rule, which can be referred to as an ECCE-to-EREG mapping. There are two types of ECCE-to-EREG mapping: localized transmission and distributed transmission. An EREG group constituting one ECCE in the local transmission is selected in the EREG in one PRB pair.

For example, suppose that one ECCE includes four EREGs, and one EPDCCH set is configured to include four PRB pairs.

3, ECCE # 0 = {EREG 0, EREG 4, EREG 8, EREG 12}, ECCE # 1 = {EREG 1, EREG 5, EREG 9, EREG 3} in PRB pair # 0, , ECCE # 2 = {EREG 2, EREG 6, EREG 10, EREG 14}, ECCE # 3 = {EREG 3, EREG 7, EREG 11, EREG 15}. This also applies to PRB pairs # 1, # 2 and # 3. Or one ECCE is configured to include eight EREGs, ECCE # 0 = {EREG 0, EREG 2, EREG 4, EREG 6, EREG 8, EREG 10, EREG 12, EREG 14} EREG 1, EREG 3, EREG 5, EREG 7, EREG 9, EREG 11, EREG 13, EREG 15}.

On the other hand, according to the distributed transmission, as shown in FIG. 4, an EREG group constituting one ECCE is selected from EREGs of different PRB pairs. For example, ECCE # 0 = EREG 0 of {PRB pair # 0, EREG 4 of PRB pair # 1, EREG 8 of PRB pair # 2, EREG 12 of PRB pair # 3). This applies equally to other ECCEs.

EPDCCH based on local transmission may be referred to as local EPDCCH, and EPDCCH based on distributed transmission may be referred to as distributed EPDCCH. The distributed EPDCCH can obtain a diversity gain, and the local EPDCCH can be used for control information transmission through preferred precoding for a specific terminal with frequency selective characteristics.

The base station can transmit a plurality of EPDCCHs in one subframe. The terminal monitors at least one common EPDCCH in the common search space for each subframe, or at least one terminal-specific EPDCCH in the UE- Can be monitored. Here, monitoring means that the UE attempts to decode the EPDCCH according to the EPDCCH format. Monitoring may also be referred to as blind decoding.

The blind decoding demasking a cyclic redundancy check (CRC) of the received EPDCCH (referred to as an EPDCCH candidate) by an identifier related to the common control information, checks the CRC error, It is a method to check whether or not it is a channel. The reason for performing blind decoding is that the UE does not know in advance where the EPDCCH is transmitted in the common search space or in the UE-specific search space and in which aggregation unit or DCI format.

To reduce the burden of blind decoding, a search space (SS) can be used. The search space is a monitoring set of the ECCE for EPDCCH. The search space is divided into a common search space and a terminal-specific search space. The terminal monitors the EPDCCH within the search space. The common search space is a space for searching an EPDCCH having common downlink control information such as system information, paging information, and transmission power control information. The UE-specific search space is a space for searching an EPDCCH having dedicated downlink control information for each UE.

The starting point of the search space may be defined differently from the common search space and the terminal specific search space. For example, although the starting point of the common search space is fixed regardless of the sub-frame, the starting point of the UE-specific search space may be a terminal identifier (for example, a cell-radio network temporary identifier (C-RNTI) Or a slot number in a radio frame. When the starting point of the UE-specific search space is within the common search space, the UE-specific search space and the common search space may overlap.

In order for the UE to monitor the EPDCCH in the common search space and / or the UE-specific search space, the amount of the ECCE constituting the common search space or the UE-specific search space, the aggregation level of the ECCE, The number of EPDCCH candidates according to a predetermined rule or a combination thereof must be defined according to a certain rule. The definitions of these rules are called EPDCCH assignment rules in this specification. The EPDCCH allocation rule is a communication protocol in which the BS and the MS promise to each other. That is, a procedure for the base station to transmit the EPDCCH to the UE, the number of monitoring times of the UE, and the like are determined according to the EPDCCH allocation rule.

In defining the EPDCCH allocation rule, there may be considered factors such as the number of resource elements n _EPDCCH available in the EPDCCH within one PRB pair, the DCI format, and the coding rate for the common DCI.

First, the number of resource elements available to the EPDCCH may be different according to the frame configuration such as the type of the subframe, the type of the CP, the distribution of the reference signal, and the existing control region. For example, the number of available resource elements (or ECCE) n _EPDCCH may be derived from the CP type in the normal subframe as shown in Table 3 below.

Normal subframe, normal CP Normal subframe, extended CP (12 * 14) -24 = 144 REs (12 * 12) -16 = 128 REs Four ECCEs per PRB pair
(4 EREGs per ECCE) Two ECCEs per PRB pair
(8 EREGs per ECCE)

In the configuration of the special subframe using the normal CP, the number of available resource elements n _EPDCCH in one PRB pair can be derived as shown in Table 4 below.

Normal CP, Special subframe composition One 2 3 4 6 7 8 9 DwPTS length (OFDM symbol number) 9 10 11 12 9 10 11 6 DM RS for RE
REs excluded 84 96 108 120 84 96 108 60

Referring to Table 4, the DwPTS length (the number of OFDM symbols) is determined according to the special subframe configurations 1 to 9, and the number of resource elements REs available in the EPDCCH is classified accordingly. In the case of the special subframe configuration, n _EPDCCH changes depending on the length of the DwPTS.

In the configuration of the special subframe using the extended CP, the number of available resource elements n _EPDCCH in one PRB pair can be derived as shown in Table 5 below.

Extended CP, special sub-frame configuration One 2 3 5 6 DwPTS length (OFDM symbol number) 8 9 10 8 9 DM RS for RE
REs excluded 88 100 112 88 100

Referring to Table 5, the DwPTS length (the number of OFDM symbols) and the number of resource elements (REs) available in the EPDCCH are classified according to the special subframe configurations 1 to 6.

As described above, the difference in the number of resource elements available to the EPDCCH according to the frame configuration may result in a difference in size and number of EPDCCHs. However, from the viewpoint of link adaptation, the link performance experienced by one EPDCCH needs to be uniform regardless of the frame configuration. Therefore, the EPDCCH allocation rule should be defined such that the link performance of the EPDCCH is not affected by the difference of each frame configuration.

Next, in defining the EPDCCH allocation rule, there is a DCI format as another factor to be considered. The DCI includes uplink scheduling information (referred to as an uplink grant) or downlink scheduling information (referred to as a downlink grant), an uplink power control command, control information for paging, Control information for indicating a random access response (RACH response), and the like. The DCI can be transmitted with a certain format, and can be used according to each DCI format. For example, the usage of the DCI format can be divided as shown in Table 6 below.

DCI format Explanation 0 Used for scheduling of PUSCH (uplink grant) One Used for scheduling one PDSCH codeword in one cell 1A Used for simple scheduling of one PDSCH codeword in one cell and in a random access procedure initiated by a PDCCH command. 1B Used for simple scheduling of one PDSCH codeword in one cell using precoding information 1C Used for brief scheduling of one PDSCH codeword and notification of MCCH changes 1D Used for simple scheduling of one PDSCH codeword in one cell, including precoding and power offset information. 2 Used for PDSCH scheduling for terminals configured in spatial multiplexing mode. 2A Used for PDSCH scheduling of UEs configured in CDD mode with large delay. 2C Used in transmission mode 9 (multi-layer transmission) 2D Used to support CoMP transmission 3 Used for transmission of TPC commands for PUCCH and PUSCH with 2-bit power adjustment 3A Used for transmission of TPC commands for PUCCH and PUSCH with single bit power adjustment.

Referring to Table 6, DCI format 0 is an uplink grant, and includes format 1 for scheduling one PDSCH codeword, format 1A for compact scheduling of one PDSCH codeword, very simple scheduling of DL-SCH A format 2 for PDSCH scheduling in a closed-loop spatial multiplexing mode, a format 2A for PDSCH scheduling in an open-loop spatial multiplexing mode, a format 2 for an uplink channel And formats 3 and 3A for transmission of TPC (Transmission Power Control) commands.

Each field of the DCI is sequentially mapped to _n information bits a ₀ through a _{n -1} . For example, if the DCI is mapped to a total of 43 bits of information bits, each DCI field is sequentially mapped to a ₀ to a ₄₂ . DCI formats 0, 1A, 3, and 3A all have the same payload size, while the remaining DCI formats have payload sizes mutually.

To map a large DCI format to an EPDCCH, a relatively large number of ECCEs or resource elements are required. On the other hand, mapping a small DCI format to EPDCCH requires relatively few ECCEs or resource elements. However, in terms of link adaptation, the link performance experienced by each EPDCCH needs to be uniform regardless of the DCI format. Therefore, the EPDCCH allocation rule should be defined in consideration of the DCI format.

Finally, another factor to consider in defining the EPDCCH assignment rule is the coding rate. Based on the number of different resource elements available for each ECCE with different public DCI formats, the coding rate can be evaluated, for example, as shown in Table 7 below.

DCI format 1.4MHz 5MHz 10MHz 20MHz 0 / 1A / 3 / 3A s = 37,
r = 0.71 / 0.62 / 0.51 s = 41,
r = 0.79 / 0.68 / 0.57 s = 43,
r = 0.83 / 0.72 / 0.60 s = 45,
r = 0.87 / 0.75 / 0.63 1C s = 24,
r = 0.46 / 0.40 / 0.33 s = 28,
r = 0.54 / 0.47 / 0.38 s = 29, r = 0.56 / 0.48 / 0.40 s = 31, r = 0.60 / 0.52 / 0.43

Referring to Table 7, S is the coding rate for S, assuming that DCI is the size (i.e., number of bits) and r is the number of REs per ECCE is 26/30/36. In view of Table 4, the link performance for the EPDCCH transmission can be deduced when the aggregation level = 1 (that is, when one ECCE constituting one EPDCCH is one).

Hereinafter, an EPDCCH in consideration of at least one of factors affecting the EPDCCH allocation rule, that is, the number n _EPDCCH of the resource elements available in the EPDCCH in one PRB pair or the coding rate for ECCE, DCI format, and common DCI, An allocation rule is started. In addition, although the EPDCCH allocation rule described below is described based on the common search space, it goes without saying that this EPDCCH allocation rule can be applied to the UE-specific search space as well. There are various embodiments of the EPDCCH allocation rule, and this is disclosed below.

1. EPDCCH allocation rule considering number of ECCEs

The EPDCCH allocation rule according to the present embodiment differs from the EPDCCH allocation rule when the number of ECCEs in one PRB pair is different. That is, an EPDCCH allocation rule is defined based on the number of ECCEs per PRB pair.

For example, when the number of ECCEs in a PRB pair is 4 (hereinafter, case 1) and 2 (case 2 below), there are different EPDCCH allocation rules. Case 1 includes i) a normal CP and a normal subframe, or ii) a case of a normal CP and a special subframe configuration 3, 4, 8. These are cases in which the number of ECCEs = 4 in one PRB pair is satisfied.

And Case 2 includes i) normal CP and special subframes 1,2,6,7,9, or ii) extended CP and normal subframes, or iii) extended CP and special subframe configurations 1,2,3 , 5, and 6, respectively. These are cases in which the number of ECCEs = 2 in one PRB pair is satisfied.

On the other hand, in designing the EPDCCH allocation rule, at least one of the following design conditions may be applied.

Design condition Contents One Based on distributed transmission 2 The maximum number of EPDCCH candidates is 6 3 The aggregation unit in the PRB pair having two ECCEs may be smaller than the aggregation unit in the PRB pair having four ECCEs, or conversely, the aggregation unit in the PRB pair having four ECCEs may be smaller in the PRB pair having two ECCEs May be larger than the aggregation unit of 4 The number of PRB pairs included in the EPDCCH set may not support 2. 5 Aggregation units can be supported up to 16, 32

Referring to Table 8, design condition 1 indicates that the EPDCCH allocation is according to the distributed transmission. In the design condition 2, the number of maximum EPDCCH candidates (i.e., the number of monitoring times) is limited to six, but this is merely an example, and may be limited to other values. Design condition 3 is included because PRB pairs with two ECCEs are likely to support a low coding rate. That is, a PRB pair having two ECCEs can support a lower aggregation unit than an aggregation unit of PRB pairs having four ECCEs. Conversely, the aggregation unit in the PRB pair having four ECCEs can be larger than the aggregation unit in the PRB pair having two ECCEs. The reason that the design condition 4 is included is that if the number of PRB pairs included in the EPDCCH set N _RB ^Xp is 2, only a small number of EPDCCH candidates can be supported and it may be difficult to support some aggregation units to be. Rather, N _RB ^Xp = 16 may be supported for the EPDCCH of the common search space. The reason that the design condition 5 is included is to improve the link performance of the EPDCCH in the common search space. That is, up to 16, 32 can be supported in addition to aggregation unit 4 or 8. The aggregation unit represents the number of ECCEs constituting one EPDCCH. For example, if the aggregation unit is 4, 4 ECCEs are gathered to form one EPDCCH.

(1) First embodiment: defined only when the aggregation unit (L) is 4 and 8

5 is a table showing the allocation of EPDCCH candidates monitored by the UE according to an example of the present invention.

Referring to FIG. 5, the number of EPDCCH candidates (i.e., EPDCCH blind decoding) is calculated when N _RB ^Xp = 2 in case 1 (i.e., 4ECECs per PRB pair is included) The number of EPDCCH blind decodings is 1 when the aggregation unit L is 2 and the aggregation unit L = 8. This is because design condition 2 is applied when the number of EPDCCH candidates for L = 4 and L = 8 in each N _RB ^Xp is 6 or less.

On the other hand, the number of EPDCCH candidates (i.e., the number of EPDCCH blind decodings) at the time of aggregation unit (L) = 4 when Case 2 (i.e., 2 ECCEs per PRB pair is included) is N _RB ^Xp = 1, and the number of EPDCCH candidates (i.e., the number of EPDCCH blind decodings) when the aggregation unit (L) = 8 is zero. This is because design condition 2 is applied when the number of EPDCCH candidates for L = 4 and L = 8 in each N _RB ^Xp is 6 or less.

(2) Second embodiment: Design condition 3 is applied to the EPDCCH allocation rule. If the aggregation unit (L) in Case 1 is larger than Case 2

FIG. 6 is a table showing assignments of EPDCCH candidates monitored by a UE according to another example of the present invention.

Referring to FIG. 6, the aggregation units (L) defined in Case 1 are 8 and 16, and the aggregation units (L) defined in Case 2 are 4 and 8, which is 1/2 of Case 1. However, the number of EPDCCH candidates (ie, the number of EPDCCH blind decodings) is the same for each L when Case 1 and Case 2 are N _RB ^Xp = 2, 4, and 8.

7 is a table showing assignments of EPDCCH candidates monitored by a UE according to another example of the present invention. This is the case where the aggregation unit (L) = 32 is added to the EPDCCH allocation rule of Case 1 in FIG.

8 is a table showing the allocation of EPDCCH candidates monitored by the UE according to another example of the present invention. This is the case where the aggregation unit (L) = 32 is added to the EPDCCH allocation rule of Case 1 in FIG. 6 and the aggregation unit (L) = 16 is added to the EPDCCH allocation rule of Case 2.

Based on the EPDCCH assignment rules according to FIGS. 5-8, there may be more combinations of Case 1 and Case 2, and these combinations are also included in the embodiments of the present disclosure.

(3) Third embodiment: When design condition 3 is applied to the EPDCCH allocation rule and a smaller aggregation unit is applied to Case 2 than Case 1

9 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention. This is the case where the smaller aggregation unit L = 2 is applied to Case 2.

Referring to FIG. 9, Case 1 is the same as Case 1 of FIG. 6, and Case 2 is changed. That is, in Case 2, the smaller aggregation unit L = 2 is applied. Case 2 is able to support more EPDCCH candidates through a smaller L with a somewhat lower coding rate because the EREG or resource elements included in the ECCE are relatively large compared to Case 1. In particular, the number of EPDCCH candidates at a small N _RB ^Xp value (i.e., N _RB ^Xp = 2 or N _RB ^Xp = 4) may increase.

As a result, the blocking probability for the EPDCCH of the common search space can be reduced, and more EPDCCHs can be allocated in Case 2 in comparison with the EPDCCH allocation rules of FIG. 5 to FIG.

10 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention. This is a case where the aggregation unit (L) = 16 is additionally defined in the EPDCCH allocation rule of Case 1 and Case 2 in FIG.

11 is a table showing the allocation of EPDCCH candidates monitored by the UE according to another example of the present invention. This is the case where Case 1 of FIG. 9 is used as is, and the aggregation units (L) = 1 and 16 are additionally defined in the EPDCCH allocation rule of Case 2.

12 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention. This is a combination of Case 1 of FIG. 10 and Case 2 of FIG.

FIG. 13 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention. This is a case where L = 2 is additionally defined in the EPDCCH allocation rule of Case 1 in FIG. Case 2 is the same as FIG.

Based on the EPDCCH assignment rules according to FIGS. 9-13, there may be more combinations of Case 1 and Case 2, and these combinations are also included in the embodiments of the present disclosure.

(4) Fourth Embodiment: Number of PRB pairs in EPDCCH set N _RB If extended support is available up to ^Xp = 16 (useful when the system bandwidth is large)

Figure 14 is a table showing assignments of EPDCCH candidates monitored by a UE according to another example of the present invention. This is the case where L = 4, 8 is defined in the EPDCCH allocation rule of Case 1, and L = 2, 4, 8 is defined in the EPDCCH allocation rule of Case 2.

15 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention. This is the case where L defined in Case 1 is larger than L defined in Case 2 based on Design Condition 3. That is, L = 8, 16 defined in Case 1, and L = 4, 8 defined in Case 2.

16 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention. This is the case where L defined in Case 1 and L defined in Case 2 are the same. That is, L = 4, 8, and 16 are defined in Case 1 and Case 2.

17 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention. L = L = 8, 16, 32 defined in Case 1 and L = 4, 8, 16 defined in Case 2 are different from L defined in Case 1 and L defined in Case 2.

18 is a table showing assignments of EPDCCH candidates monitored by a UE according to another example of the present invention. L = L = 8, 16, 32 defined in Case 1 and L = 4, 8, 16 defined in Case 2 are different from L defined in Case 1 and L defined in Case 2. 17, the number of EPDCCH candidates is different for each L at N _RB ^Xp = 16. For example, the number of EPDCCH candidates in FIG. 17 is 3, 2, 1 when L = 8,16,32 (or L = 4,8,16 in Case 2) in Case 1, whereas the number of EPDCCH candidates in FIG. The number is 2, 2, 2. Also in this case, the total sum of the number of EPDCCH candidates (i.e., the total number of times the terminal must monitor the EPDCCH) is 6 or less according to the design condition 2.

Based on the EPDCCH assignment rules according to FIGS. 14-18, there may be more combinations of Case 1 and Case 2, and these combinations are also included in the embodiments of the present disclosure.

In the first to fourth embodiments, in determining or analyzing which EPDCCH allocation rule is optimal, the coding rate is compared with the DCI format 1C mapped to the EPDCCH of the common search space as an example. In the 1.4 MHz system band, the payload of DCI format 1C is 24 bits. 19, the coding rate of the conventional PDCCH, the coding rate of EPDCCH Case 1, and the coding rate of EPDCCH Case 2 for L = 1, 2, 4, 8, 16 and 32 are shown in FIG.

Here, a representative value of each case is assumed as the number of resource elements to be a reference of the coding rate. For example, it is assumed that 36 resource elements per CCE in the legacy case of the conventional PDCCH, 26 resource elements per ECCE in case 1, and 36 resource elements per ECCE in case 2 are included. Based on the comparative analysis shown in FIG. 19, the optimal L can be selected for each case.

Referring to FIG. 19, in case of L = 4, four ECCEs constitute one EPDCCH and there are 26 resource elements (REs) per ECCE. Therefore, one EPDCCH includes 4 * 26 = 104 resources Elements exist. When modulation level is QPSK (quadrature phase shift keying), 2 bits are transmitted per one resource element, so a total of 208 bits can be transmitted through 104 resource elements. If a 24-bit DCI format 1C is mapped to one EPDCCH to which a total of 208 bits can be transmitted, the coding rate becomes 24/208 = 0.115. That is, when L = 4, the coding rate is 0.115, which is relatively high. On the other hand, when L = 8, the coding rate is as low as 0.0575. When L = 16, 32, the coding rate is lower. Therefore, in Case 1, the EPDCCH allocation rule can be defined to define only L = 8, 16, 32. On the other hand, in Case 2, the coding rate is not defined when L = 1, 2. When L = 4, the coding rate is 0.0825, which is equal to the coding rate when L = 4 in the CCE of the conventional PDCCH, thus ensuring link performance. When L = 8, 16, the coding rate is lower. Therefore, in Case 2, the EPDCCH assignment rule can be defined to define L = 4, 8, and 16. Based on the analysis according to FIG. 19, deriving the optimal EPDCCH allocation rule is as shown in FIG.

20 is a table showing assignments of EPDCCH candidates monitored by a UE according to another example of the present invention.

20, L defined in Case 1 is different from L defined in Case 2, L = 8, 16, and 32 defined in Case 1 as shown in FIG. 17, and L = 4, 8, and 16, respectively. However, as compared with FIG. 17, in FIG. 20, N _RB ^Xp = 2, 4, 8, 16 are extendedly supported.

In Case 1, the number of REs available for one ECCE in one PRB pair is less than Case 2. Therefore, a higher L should be supported to guarantee link performance of one EPDCCH transmission. That is, in Case 1, L = 8 is defined.

Case 2 has a margin in terms of coding rate, so it can be supported from L = 4. In addition, in order to support a sufficiently low coding rate for the EPDCCH of the common search space and to support a sufficient number of EPDCCH candidates, the EPDCCH allocation rule of FIG. 20 is additionally defined as N _RB ^Xp = 16 compared with the coding rate for the conventional PDCCH will be. Of course, embodiments in which N _RB ^Xp = 16 are excluded in the EPDCCH allocation rule of FIG. 20 may be considered in some cases.

Further, in Fig. 20 when the N _RB ^Xp = 2 is because it supports the so-limiting EPDCCH candidates, in EPDCCH assignment rules according to one embodiment of the case where N _RB ^Xp = 2 may be excluded, which is shown in Figure 21 .

The EPDCCH allocation rules according to FIGS. 20 and 21 can be applied to all system bands, but not when N _RB ^Xp > N _RB ^DL .

On the other hand, in cases 1 and 2 in FIG. 20 or 21, since only the limited number of EPDCCH candidates is defined in the case of N _RB ^DL = 6 (i.e., the system band = 1.5 MHz) The number of EPDCCHs that can be used may be limited. This can delay transmission and reception of the information on the entire system. Therefore, the EPDCCH allocation rule according to the present embodiment can be defined as cases 3 and 4 except for the case of N _RB ^DL = 6. The EPDCCH allocation rule according to cases 3 and 4 is as shown in FIG.

22 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention.

Referring to FIG. 22, there is an advantage in that the number of EPDCCH candidates can be supported for N _RB ^DL = 6 although L = 2 and 4 require relaxation of the requirements of the EPDCCH link performance. However, cases 3 and 4 relax the requirements of the EPDCCH link performance and can be used only when it is higher than the existing PDCCH coding rate criterion.

2. EPDCCH allocation rule considering number of ECCEs and coding rate

The EPDCCH allocation rule according to this embodiment differs from the EPDCCH allocation rule in consideration of the number of ECCEs and the coding rate in one PRB pair. That is, the EPDCCH allocation rule is defined in consideration of the increase / decrease of the coding rate considering the number of ECCEs per one PRB pair and the overhead of other reference signals. According to this, various combinations of ECCE number and coding rate are classified as Case 1, Case 2 or Case 3. And the EPDCCH allocation rules of Case 1, Case 2, and Case 3 may be different from each other.

In defining the conditions included in the cases 1, 2 and 3, the DCI formats 1C / 3 / 3A carrying the common control information may not be distinguished (the fifth embodiment), and the coding rate of the DCI format 1C The DCI format 1C and the DCI format 3 / 3A can be distinguished from each other in consideration of the margin (sixth embodiment).

According to the fifth embodiment, the conditions included in cases 1, 2, and 3 can be defined as shown in Table 9 below.

PRB Number of ECCEs per pair Coding rate related conditions Case 1 4 (i. _e ., all DCI formats on the CSS) in the case of a normal subframe, a normal CP, n _EPDCCH < 104 (or 100, 96, ...), DCI format 1C / or
(ii) In the case of the special subframe configurations 3, 4 and 8, the normal CP, n _EPDCCH <104 (or 100, 96, ...), DCI format 1C / 1A / _0/3 / All DCI formats) Case 2 2 (i) normal subframe, extended CP, DCI format 1C / 1A / 0/3 / 3A (in other words, all DCI formats on CSS), or
(ii) Special subframe configuration 1, 2, 6, 7, 9, Normal CP, DCI format 1C / 1A / 0/3 / 3A (ie all DCI formats on the CSS)
(iii) Special subframe configuration 1, 2, 3, 5, 6, extended CP, DCI format 1C / 1A / 0/3 / 3A (ie all DCI formats on CSS) Case 3 4 or 2 The case where four ECCEs are included in one PRB pair, except for cases corresponding to Case 1

Referring to Table 9, the condition of n _EPDCCH <104 is a threshold, and the _cases are classified based on the threshold value. Particularly, in the present embodiment, the reason why the threshold value is defined as 104 is that the number is a multiple of less than 108. If the threshold value is 108, as shown in Table 4, the normal CP / special subframe configurations 3 and 8 always correspond to Case 1, meaning that there is no meaning to distinguish cases. Therefore, we use 104, which is a multiple of 4, to divide the cases. It should be a multiple of 4 in order to provide a uniform number of REs for each CCE since there are four ECCEs in one PRB pair.

According to the sixth embodiment, the conditions included in the cases 1, 2 and 3 can be defined as shown in Table 10 below.

PRB Number of ECCEs per pair Coding rate related conditions Case 1 4 (i) normal subframe, normal CP, n _EPDCCH <104, DCI format 1A / _0/3 / 3A, or
(ii) Normal subframe, Normal CP, n _EPDCCH <100 (or 96, 92, 88, ...), DCI format 1C (the threshold value above is four times less than 104), or
(iii) Special subframe configuration 3, 4, 8, Normal CP, n _EPDCCH <104, DCI format 1A / _0/3 / 3A, or
(iv) Special subframe configuration 3, 4, 8, Normal CP, n _EPDCCH <100 (or 96, 92, 88, ...), DCI format 1C Case 2 2 (i) normal subframe, extended CP, DCI format 1C / 1A / 0/3 / 3A, or
(ii) Special subframe configuration 1, 2, 6, 7, 9, Normal CP, DCI format 1C / 1A / 0/3 / 3A, or
(iii) Special subframe configuration 1, 2, 3, 5, 6, extended CP, DCI format 1C / 1A / 0/3 / 3A Case 3 4 or 2 The case where four ECCEs are included in one PRB pair, except for cases corresponding to Case 1

Referring to Table 10, the sixth embodiment (Table 10) is different from the fifth embodiment (Table 9) in that only the condition corresponding to Case 1 is distinguished between DCI format 1C and 1A / 0/3 / 3A And the conditions corresponding to Case 2 and the conditions corresponding to Case 3 are the same as those of the fifth embodiment.

In the fifth and sixth embodiments, in order to derive the optimum EPDCCH allocation rule, the coding rate is compared with the DCI format 1C mapped to the EPDCCH of the common search space as an example. In the 1.4 MHz system band, the payload of DCI format 1C is 24 bits. Comparing the coding rate of the conventional PDCCH for L = 1, 2, 4, 8, 16, 32, the coding rate of EPDCCH Case 1, the coding rate of EPDCCH Case 2 and the coding rate of EPDCCH Case 3, same.

Here, the number of resource elements as a reference of the coding rate is assumed to be a typical value of each case. For example, 36 resource elements per CCE in the legacy case, 26 resource elements per ECCE in Case 1, 36 resource elements per ECCE in Case 2, 30 resource elements per ECCE in Case 3, Are included. Based on the comparative analysis as shown in FIG. 23, L can be selected for each case.

Referring to FIG. 23, in Case 1, the coding rate is as high as 0.115 when L = 4, whereas the coding rate is as low as 0.0575 when L = 8. When L = 16, 32, the coding rate is lower. Therefore, in Case 1, the EPDCCH allocation rule can be defined to define only L = 8, 16, 32. On the other hand, in Case 2, the coding rate is not defined when L = 1, 2. When L = 4, the coding rate is 0.0825, which is equal to the coding rate when L = 4 in the CCE of the conventional PDCCH, thus ensuring link performance. When L = 8, 16, the coding rate is lower. Therefore, in Case 2, the EPDCCH assignment rule can be defined to define L = 4, 8, and 16. On the other hand, in Case 3, the coding rate is not defined when L = 1, 2. The coding rate at L = 4 is 0.1, which is slightly higher than the coding rate at L = 4 in the CCE of the conventional PDCCH. When L = 8, 16, the coding rate is lower. Therefore, in Case 3, the EPDCCH allocation rule can be defined to define L = 4, 8, 16 or L = 8, 16, 32. Based on the analysis according to FIG. 23, the optimal EPDCCH allocation rule is derived as shown in FIG. 24A or 24B.

24A is a table showing assignments of EPDCCH candidates monitored by a UE according to another example of the present invention.

Referring to FIG. 24A, L = 8, 16, and 32 defined in Case 1, and L = 4, 8, and 16 defined in Case 2 and Case 3. And extended to N _RB ^Xp = 2, 4, 8, 16.

 In Case 1, the number of REs available for one ECCE in one PRB pair is less than Case 2 and Case 3. Therefore, a higher L should be supported to guarantee link performance of one EPDCCH transmission. That is, in Case 1, L = 8 is defined.

Case 2 and Case 3 have a margin in terms of coding rate, so they can be supported from L = 4. Also, in order to support a sufficiently low coding rate for the EPDCCH of the common search space and to support a sufficient number of EPDCCH candidates with respect to the coding rate for the conventional PDCCH, the EPDCCH allocation rule of FIG. 24A is additionally defined as N _RB ^Xp = 16 will be. Of course, embodiments in which N _RB ^Xp = 16 are excluded in the EPDCCH allocation rule of FIG. 24A may be considered in some cases.

FIG. 24B is a table showing allocation of EPDCCH candidates monitored by the UE according to another example of the present invention. FIG.

Referring to FIG. 24B, Case 1 and Case 2 are the same in FIG. 24A, but Case 3 is changed. Case 3 can be supported as L = 8, 16, 32 because of margin in terms of coding rate.

FIG. 24C is a table showing assignments of EPDCCH candidates monitored by a UE according to another example of the present invention. FIG.

Referring to FIG. 24C, Case 1 and Case 2 are the same in FIG. 24A, but NRBXp = 2 in Case 3 is excluded.

In addition, in the case of N _RB ^Xp = 2 supporting the EPDCCH candidates which are too limited in FIG. 24A, it is also possible to consider an embodiment in which all of the EPDCCH allocation rules of Cases 1, 2 and 3 are excluded, as shown in FIG.

The EPDCCH allocation rule according to FIGS. 24A to 24C and FIG. 25 can be applied to all system bands, but it can not be supported when N _RB ^Xp > N _RB ^DL .

On the other hand, in Figure 24a to Figure 24c or Figure 25 of the Case 1, 2, 3, N RB DL = 6 , since (i. E., The system bandwidth = 1.5MHz, 6PRB) and the tens of thousands of the so-limiting EPDCCH candidate defined when: , The number of EPDCCHs capable of simultaneously transmitting the common control information can be limited. This can delay transmission and reception of the information on the entire system. Therefore, the EPDCCH allocation rule according to the present embodiment can be defined as cases 3 and 4 except for the case of N _RB ^DL = 6. The EPDCCH allocation rule according to cases 4 and 5 is shown in FIG. Here, there are 4 ECCEs per PRB.

26 is a table showing allocation of EPDCCH candidates monitored by a UE according to another example of the present invention.

Referring to FIG. 26, there is an advantage that the number of EPDCCH candidates can be supported for N _RB ^DL = 6 although L = 2 and 4 require relaxation of requirements of the EPDCCH link performance. However, Case 4, 5 is a relaxation of the requirements of EPDCCH link performance and can be used only when it is higher than the existing PDCCH coding rate criterion.

3. EPDCCH allocation rule when at least one PRB pair among pairs of PRBs for transmission of common EPDCCH is set in a central 6PRB pair to which signals such as PBCH and PSS / SSS are transmitted

In the NCT-based communication system, the EPDCCH set can be set in the central 6PRB pair where the PBCH or the PSS / SSS is transmitted. Therefore, in this case, the EPDCCH allocation rule must be defined.

If the EPDCCH in the public search space is transmitted on an antenna port such as PBCH and / or at least one of the PSS / SSS (in particular PBCH), then the REs used for the PBCH or PSS / SSS are not used as REs available to the EPDCCH I suppose. REs for the existing CRS, zero-power CSI-RS, NZP (non-zero power) -CSI-RS, and legacy control regions are not used for EPDCCH, and additionally, PBCH and / / SSS can be considered.

PBCH, and PSS / SSS, the number of EREGs included in each ECCE can be defined as shown in Table 11.

Normal CP Expanded CP The normal subframe Special subframe configurations 3,4,8 Special subframe configuration 1,2,6,7,9 The normal subframe Special subframe structure 1,2,3,5,6 8

Referring to Table 11, N _ECCE ^EREG , which is the number of EREGs constituting one ECCE, is defined according to the type and CP type of each subframe. In any case, N _ECCE ^EREG is 8 in the PRB pair.

Conditions included in cases 1, 2, and 3 can be defined as shown in Table 12 below.

PRB Number of ECCEs per pair Coding rate related conditions Case 1 2 (i) in the case of normal subframe, extended CP, DCI format 1C / 1A / 1B / 1D / 1 / 2A / 2B / 2C / 2D / 4/0/3 / 3A
(ii) Normal subframe, Normal CP, DCI format 1C / 1A / 1B / 1D / 1 / 2A / 2B / 2C / 2D / 4/0/3 / 3A
(iii) Special subframe configuration 1, 2, 3, 4, 6, 7, 8, 9, Normal CP, DCI format 1C / 1A / 1B / 1D / 1 / 2A / 2B / 2C / 2D / 3 / 3A, or
(iv) Special subframe configuration 1, 2, 3, 5, 6, extended CP, DCI format 1C / 1A / 1B / 1D / 1 / 2A / 2B / 2C / 2D / 4/0/3 / 3A

Or the number of EREGs included in each ECCE can be defined as shown in Table 13. [

Normal CP Expanded CP The normal subframe Special subframe configurations 3,4,8 Special subframe configuration 1,2,6,7,9 The normal subframe Special subframe structure 1,2,3,5,6 8 4 8

Referring to Table 13, in the PRB pair consisting of the normal CP and a normal sub-frame N _ECCE and ^EREG is 8, and the normal CP and the special sub-frame configuration of 3,4,8 PRB pairs N _ECCE ^EREG is 4, and the rest of the case N _ECCE ^EREG is 8.

The EPDCCH allocation rule considering the PBCH and / or the PSS / SSS is defined by considering the increase / decrease of the coding rate considering the number of ECCEs per one PRB pair and the overhead of other reference signals. According to this, various combinations of ECCE number and coding rate are classified as Case 1, Case 2 or Case 3. And the EPDCCH allocation rules of Case 1, Case 2, and Case 3 may be different from each other.

Conditions included in cases 1, 2, and 3 can be defined as shown in Table 14 below.

PRB Number of ECCEs per pair Coding rate related conditions Case 1 2 (i) Special subframe configuration 3, 4, 8, Normal CP, DCI format 2 / 2A / 2B / 2C / 2D is monitored, or
(ii) Special subframe configurations 3, 4, 8, Normal CP, nEPDCCH <104 (or 100, 96, ...), DCI format 1C / 1A / 1B / 1D / 1 / 2A / 2B / 2C / 2D / 4/0/3 / 3A Case 2 2 (i) in the case of normal subframe, extended CP, DCI format 1C / 1A / 1B / 1D / 1 / 2A / 2B / 2C / 2D / 4/0/3 / 3A
(ii) Normal subframe, Normal CP, DCI format 1C / 1A / 1B / 1D / 1 / 2A / 2B / 2C / 2D / 4/0/3 / 3A
(iii) Special subframe configuration In case of 1, 2, 6, 7, 9, Normal CP, DCI format 1C / 1A / 1B / 1D / 1 / 2A / 2B / 2C / 2D / 4/0 / or
(iv) Special subframe configuration 1, 2, 3, 5, 6, extended CP, DCI format 1C / 1A / 1B / 1D / 1 / 2A / 2B / 2C / 2D / 4/0/3 / 3A Case 3 4 or 2 The case where four ECCEs are included in one PRB pair, except for cases corresponding to Case 1

Here, at least one of the PRB pairs set for the CSS EPDCCH may be set to the middle 6 PRB pairs (i.e., the PRB pair to which the PBCH and the PSS / SSS are transmitted). In this case, the number of EREGs included in each ECCE can be determined as follows. As an example, the number of EREGs included in each ECCE is the same regardless of the subframe type or CP type, and the EPDCCH allocation rule corresponding to Case 2 proposed in the present invention is applied. For example, as shown in Table 11, one ECCE may include 8EREG. As another example, according to Table 13, in case of the normal CP and the normal subframe, the EPDCCH allocation rule corresponding to Case 2 is applied.

Now, the process of transmitting and receiving EPDCCH between the UE and the BS using the EPDCCH allocation rule will be described in detail.

FIG. 27 is a flowchart illustrating a process in which an EPDCCH is transmitted and received between a terminal and a base station according to an example of the present invention.

Referring to FIG. 27, the BS adds a cyclic redundancy check (CRC) for error detection to the DCI to be transmitted to the UE (S2700). In step S2705, the base station masks an identifier (referred to as a Radio Network Temporary Identifier (RNTI)) according to the owner or use of the PDCCH in the CRC. Masking is also referred to as scrambling. If the C-RNTI is used, the EPDCCH carries control information for the corresponding specific UE, and if another RNTI is used, the EPDCCH carries the common control information received by all UEs in the cell.

For example, in the case of a UE-specific EPDCCH, the BS may mask the unique identifier of the UE, for example, C-RNTI (Cell-RNTI), to the CRC.

In another example, if the EPDCCH for a paging message transmitted over a paging channel (PCH), the base station may mask the paging identifier, e.g., P-RNTI (Paging-RNTI), to the CRC.

As another example, the base station may mask the system identifier, e.g., SI-RNTI (System Information-RNTI), to the CRC if it is an EPDCCH for system information transmitted over the DL-SCH.

As another example, if the EPDCCH is an EPDCCH for indicating a random access response, which is a response to the transmission of the UE's random access preamble, the base station may mask the Random Access-RNTI (R-RNTI) to the CRC.

The base station then performs channel coding on the control information to which the CRC is added to generate coded data (S2710).

The base station performs rate matching according to the ECCE aggregation unit (S2715). The data rate may be referred to as a coding rate according to the present embodiment.

The base station modulates the encoded data to generate modulation symbols (S2720). The number of modulation symbols constituting one ECCE can be determined according to ECCE aggregation units (one of 1, 2, 4, and 8) according to various EPDCCH allocation rules disclosed in this specification.

The base station maps the modulation symbols to the resource element of the EREG (S2725). Step S2725 may be referred to as ECCE to RE mapping.

The base station transmits the EPDCCH configured with the resource elements to which the modulation symbols are mapped to the terminal (S2730).

The terminal monitors the EPDCCH (S2735). The UE performs EPDCCH monitoring based on the number of N _RB ^Xp aggregation units and EPDCCH candidates defined in the various EPDCCH allocation rules disclosed in the present specification. Specifically, the process of monitoring the EPDCCH by the UE includes a process of demapping the resource element to the modulation symbol for the EPDCCH, a demodulation process of extracting the modulation symbol from the encoded data, a decoding process of decoding the encoded data, A process of decoding the CRC added to the DCI, and an error detection process of detecting an error.

28 is a block diagram illustrating a terminal and a base station according to an example of the present invention.

28, the terminal 2800 includes a receiving unit 2805, a terminal processor 2810, and a transmitting unit 2815. The terminal processor 2810 may further include a monitoring control unit 2811 and a data processing unit 2812.

The reception unit 2805 receives the EPDCCH and monitors the EPDCCH received under the control of the monitoring control unit 2811. The process of monitoring the EPDCCH by the receiver 2805 may include demapping the resource element to the modulation symbol for the EPDCCH based on a predetermined EPDCCH allocation rule, a demodulation process for extracting the modulation symbol from the encoded data, A decoding process of decoding the data to extract the DCI, a process of demarking the CRC added to the DCI, and an error detection process of detecting an error.

The receiving unit 2805 performs EPDCCH monitoring based on a predetermined EPDCCH allocation rule between the UE 2800 and the BS 2850. Here, the predetermined EPDCCH allocation rule between the UE 2800 and the base station 2850 may be applied to at least one of all the EPDCCH allocation rules disclosed in this specification.

For example, assuming that the EPDCCH is transmitted according to the EPDCCH allocation rule according to FIG. 7, the receiving unit 2805 selects Case 1 or 2 according to the number of ECCEs in one PRB pair, To monitor the EPDCCH candidate. Case 1 and N _RB ^Xp = 4, the receiving unit 2805 monitors two EPDCCH candidates with L = 8 and monitors one EPDCCH candidate with L = 16. That is, the receiving unit 2805 performs EPDCCH monitoring based on the number of N _RB ^Xp aggregation units and the number of EPDCCH candidates defined in the various EPDCCH allocation rules disclosed in this specification.

The monitoring control unit 2811 controls the receiving unit 2805 to monitor the EPDCCH candidate according to each aggregation unit L and sends the DCI obtained as a result of decoding of the EPDCCH in the receiving unit 2805 to the data processing unit 2812. [

The data processing unit 2812 analyzes the DCI obtained from the monitoring control unit 2811 and controls the terminal 2800 to perform a control operation indicated by the DCI. The transmission unit 2815 transmits the uplink data generated in the data processing unit 2812 to the base station 2870.

The base station 2850 includes a transmitter 2855, a receiver 2860, and a base station processor 2870. The base station processor 2870 includes an EPDCCH configuration section 2871 and a data processing section 2872.

The data processing unit 2872 generates a DCI to be sent to the terminal 2800, and adds a CRC for error detection to the DCI. The data processing unit 2872 masks an identifier such as an RNTI according to the owner or use of the PDCCH in the CRC.

For example, if the UE-specific EPDCCH is used, the data processing unit 2872 may mask the UE's unique identifier, for example, C-RNTI (Cell-RNTI), to the CRC.

In another example, if the EPDCCH for a paging message transmitted via a paging channel (PCH), the data processing unit 2872 can mask the paging identifier, e.g., P-RNTI (Paging-RNTI), to the CRC.

As another example, if the EPDCCH for system information transmitted over the DL-SCH, the data processing unit 2872 can mask the system identifier, for example, a System Information-RNTI (SI-RNTI) .

As another example, if the EPDCCH is an EPDCCH for indicating a random access response that is a response to the transmission of the UE's random access preamble, the data processing unit 2872 can mask the Random Access-RNTI (R-RNTI) to the CRC.

The data processing unit 2872 then performs channel coding on the control information to which the CRC is added to generate encoded data.

The EPDCCH constructing unit 2871 performs rate matching for each ECCE aggregation unit according to the EPDCCH allocation rule. The data rate may be referred to as a coding rate according to the present embodiment.

The EPDCCH generator 2871 modulates the encoded data to generate modulation symbols. The number of modulation symbols constituting one ECCE can be determined according to ECCE aggregation units (one of 1, 2, 4, and 8) according to various EPDCCH allocation rules disclosed in this specification.

The transmitting unit 2855 maps the modulation symbols to the resource elements of the EREG and transmits the EPDCCH composed of the resource elements to which the modulation symbols are mapped to the terminal 2800.

All of the functions described above may be performed by a processor such as a microprocessor, a controller, a microcontroller, an application specific integrated circuit (ASIC), etc. according to software or program code or the like coded to perform the function. The design, development and implementation of the above 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 (16)

A terminal for receiving a control channel in a new carrier type (NCT) based wireless communication system,
A receiver for monitoring up to six enhanced physical downlink control channel (EPDCCH) candidates in a common search space on the NCT;
A monitoring controller for controlling the reception unit to monitor the EPCCH candidate according to an aggregation level defined in any one of cases classified according to an EPDCCH allocation rule; And
A data processor for analyzing downlink control information (DCI) obtained by monitoring the EPDCCH candidate and performing an operation indicated by the DCI,
Wherein the EPDCCH allocation rule includes rules for classifying the cases based on the number of ECCEs (Enhanced Control Channel Elements) in one PRB (physical resource block) pair. The method according to claim 1,
Wherein the EPDCCH allocation rule includes a rule for classifying the cases based on at least one of a format of the DCI and a coding rate of the DCI. The method according to claim 1,
Wherein the EPDCCH allocation rule includes a rule for classifying the cases based on the number of available ECCEs per PRB pair as an additional basis. The method according to claim 1,
Wherein the number of PRB pairs included in one EPDCCH set and the number of EPDCCH candidates according to a combination of the aggregation units are individually defined for each of the cases. A method of receiving a control channel by a terminal in a new carrier type (NCT) based wireless communication system,
Monitoring up to six enhanced physical downlink control channel (EPDCCH) candidates in a common search space on the NCT;
Analyzing downlink control information (DCI) obtained by monitoring the EPDCCH candidate; And
And performing an operation indicated by the DCI,
The number of EPDCCH candidates is determined according to an aggregation level defined in any one of cases classified according to an EPDCCH allocation rule,
Wherein the EPDCCH allocation rule includes a rule for classifying the cases based on the number of ECCEs (Enhanced Control Channel Elements) in one PRB (physical resource block) pair. 6. The method of claim 5,
Wherein the EPDCCH allocation rule includes a rule for classifying the cases based on at least one of a format of the DCI and a coding rate of the DCI. 6. The method of claim 5,
Wherein the EPDCCH allocation rule includes a rule for classifying the cases based on the number of available ECCEs per PRB pair as an additional criterion. 6. The method of claim 5,
Wherein the number of PRB pairs included in one EPDCCH set and the number of EPDCCH candidates according to a combination of the aggregation units are individually defined for each of the cases. A base station for transmitting a control channel in an NCT (New Carrier Type) based wireless communication system,
The method includes generating downlink control information (DCI), adding a cyclic redundancy check (CRC) for error detection to the DCI, masking an identifier on the CRC, and performing channel coding on the DCI, A data processor for generating the data;
An EPDCCH constructor configured to generate modulation symbols by modulating the coded data and map the modulation symbols to an EPDCCH on a common search space on the NCT based on an aggregation unit according to an EPDCCH allocation rule; And
And a transmitting unit for transmitting the EPDCCH to the UE,
Up to six EPDCCH candidates are mapped on the common search space,
The number of EPDCCH candidates is determined according to an aggregation level defined in any one of cases classified according to the EPDCCH allocation rule,
Wherein the EPDCCH allocation rule comprises a rule for classifying the cases based on the number of ECCEs (Enhanced Control Channel Elements) in a pair of physical resource blocks (PRBs). 10. The method of claim 9,
Wherein the EPDCCH allocation rule includes rules for classifying the cases based on at least one of a format of the DCI and a coding rate of the DCI. 10. The method of claim 9,
Wherein the EPDCCH allocation rule includes rules for classifying the cases based on at least one of a format of the DCI and a coding rate of the DCI. 10. The method of claim 9,
Wherein the number of PRB pairs included in one EPDCCH set and the number of EPDCCH candidates according to a combination of the aggregation units are individually defined for each of the cases. A method of transmitting a control channel by a base station in a new carrier type (NCT) based wireless communication system,
Generating downlink control information (DCI);
Adding a cyclic redundancy check (CRC) for error detection to the DCI;
Masking an identifier in the CRC and performing channel coding on the DCI to generate encoded data;
Modulating the encoded data to generate modulation symbols;
Mapping the modulation symbols to an EPDCCH on a common search space on the NCT based on an aggregation unit according to an EPDCCH allocation rule; And
And transmitting the EPDCCH to a terminal,
Up to six EPDCCH candidates are mapped on the common search space,
The number of EPDCCH candidates is determined according to an aggregation level defined in any one of cases classified according to the EPDCCH allocation rule,
Wherein the EPDCCH allocation rule includes a rule for classifying the cases based on the number of ECCEs (Enhanced Control Channel Elements) in one PRB (physical resource block) pair. . 14. The method of claim 13,
Wherein the EPDCCH allocation rule includes a rule for classifying the cases based on at least one of a format of the DCI and a coding rate of the DCI. 14. The method of claim 13,
Wherein the EPDCCH allocation rule includes a rule for classifying the cases based on at least one of a format of the DCI and a coding rate of the DCI. 14. The method of claim 13,
Wherein the number of PRB pairs included in one EPDCCH set and the number of EPDCCH candidates according to a combination of the aggregation units are individually defined for each of the cases.

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