KR20150087795A - Method for transmitting and receiving downlink channel for mtc terminal and apparatus thereof - Google Patents

Abstract

The present invention relates to a method of a base station for transmitting a downlink signal for a machine-type communication (MTC) terminal and to an apparatus for the same. More specifically, the present invention relates to: a method for transmitting and receiving PBCH, PRACH, PDSCH, PDCCH or EPDCCH for a lost cost & enhanced coverage MTC terminal; and an apparatus for the same. Particularly, the present invention provides: a method of the base station for transmitting a control channel; and an apparatus for the same. The method includes the steps of: repeatedly transmitting the control channel including control information; and repeatedly transmitting a downlink data channel (PDSCH) based on information about a subframe wherein the control channel, repeatedly transmitted, ends.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method and apparatus for transmitting and receiving a downlink channel for a MTC terminal,

The present invention relates to a method and apparatus for a base station to transmit a downlink signal for a MTC (Machine Type Communication) terminal. And more particularly, to a method and apparatus for transmitting and receiving PBCH, PRACH, PDSCH, PDCCH, or EPDCCH for Low Cost & Enhanced Coverage MTC terminal.

Machine Type Communication (MTC) or machine type communication refers to the communication that takes place between a device and an object with no human intervention or minimal intervention. A "machine" may refer to an entity that does not require direct manipulation or intervention by a person, and an "MTC" may refer to a form of data communication that includes one or more of these "machines". Examples of the "machine" include a smart meter equipped with a mobile communication module, a vending machine, and the like. In recent years, a smart phone Mobile terminals with MTC function are considered as a form of "machine".

The MTC terminal can be installed in a place where the radio wave environment is worse than a general terminal such as a basement. Therefore, the coverage of the MTC terminal needs to be improved to 20 dB or more in comparison with the coverage of the general terminal. That is, the MTC terminal, which can be installed in a place where the propagation environment is bad, needs to improve its coverage or transmission / reception power in order to perform communication with the base station.

Therefore, in order for the MTC mobile station to operate at an improved coverage as compared with a conventional mobile station, it is necessary to repeatedly transmit control information and data information of the physical channel. In addition, it is necessary to define an efficient rule between the terminal and the base station in repetition for information transmission through each physical channel.

In order to solve the above-described problems, the present invention defines a subframe rule for repeated transmission of a physical channel for an MTC terminal.

The present invention also provides a method and apparatus for effectively transmitting and receiving a downlink signal by defining a relationship between transmission and reception for PBCH, PRACH, PDSCH, PDCCH, and EPDCCH as physical channels for the MTC terminal.

In one aspect, the present invention provides a method for transmitting a control channel in a base station, the method comprising: repeatedly transmitting a control channel including control information; And repeatedly transmitting the data channel (PDSCH).

According to another aspect of the present invention, there is provided a method for a terminal to receive a control channel, the method comprising: repeatedly receiving a control channel including control information; Channel (PDSCH) to the mobile station.

According to another aspect of the present invention, there is provided a base station for transmitting a control channel, comprising: a control unit for determining a specific subframe in which repeated transmission of a control channel starts; and a control channel including control information repeatedly transmitted starting from a specific subframe And a transmitter for repeatedly transmitting a downlink data channel (PDSCH) based on information on a subframe in which a control channel repeatedly transmitted ends, wherein the controller determines that a specific subframe includes a subset of at least two subframes And determines a specific subframe as one of the subframes included in the subset.

According to another aspect of the present invention, there is provided a terminal for receiving a control channel, the terminal including: a receiver for repeatedly receiving a control channel including control information; and a control unit for decoding the control channel to obtain control information, (PDSCH) based on information on a sub-frame in which a control channel is terminated.

The present invention provides an effect of enabling a MTC terminal with a wider coverage to efficiently communicate with a base station by defining a subframe rule for repeated transmission of a physical channel for the MTC terminal.

The present invention also provides a method and apparatus for effectively transmitting and receiving a downlink signal by defining a relationship between transmission and reception for PBCH, PRACH, PDSCH, PDCCH, and EPDCCH as physical channels for the MTC terminal .

1 is a diagram illustrating an example of a radio frame structure in the LTE FDD mode.
2 is a diagram for explaining a structure of a PBCH.
FIG. 3 is a diagram for explaining PBCH repeat transmission according to an embodiment of the present invention. Referring to FIG.
4 is a diagram for explaining the structure of the PRACH.
5 is a diagram illustrating an example of a method of blind decoding a PDCCH or an EPDCCH and receiving a PDSCH by the MTC terminal.
6 is a view for explaining an operation of a base station according to an embodiment of the present invention.
7 is a diagram for explaining operations of a terminal according to an embodiment of the present invention.
8 is a diagram illustrating a configuration of a base station according to an embodiment of the present invention.
9 is a diagram illustrating a configuration of a user terminal according to an embodiment of the present invention.

Hereinafter, some embodiments of the present invention 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 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 invention rather unclear.

Herein, the MTC terminal may mean a terminal supporting low cost (or low complexity) or a terminal supporting coverage enhancement. In this specification, the MTC terminal may mean a terminal supporting low cost (or low complexity) and coverage enhancement. Alternatively, the MTC terminal may refer to a terminal defined in a specific category for supporting low cost (or low complexity) and / or coverage enhancement.

The wireless communication system in the present invention is widely deployed to provide various communication services such as voice, packet data and the like. A wireless communication system includes a user equipment (UE) and a base station (BS, or eNB). The user terminal in this specification is a comprehensive concept of a terminal in wireless communication. It is a comprehensive concept which means a mobile station (MS), a user terminal (UT), an SS (User Equipment) (Subscriber Station), a wireless device, and the like.

A base station or a cell generally refers to a station that communicates with a user terminal and includes a Node-B, an evolved Node-B (eNB), a sector, a Site, a BTS A base transceiver system, an access point, a relay node, a remote radio head (RRH), a radio unit (RU), and a small cell.

That is, the base station or the cell in this specification is interpreted as a comprehensive meaning indicating a partial region or function covered by BSC (Base Station Controller) in CDMA, NodeB in WCDMA, eNB in LTE or sector (site) And covers various coverage areas such as megacell, macrocell, microcell, picocell, femtocell and relay node, RRH, RU, and small cell communication range.

Since the various cells listed above exist in the base station controlling each cell, the base station can be interpreted into two meanings. i) a device itself providing a megacell, a macrocell, a microcell, a picocell, a femtocell, or a small cell in relation to a wireless region, or ii) the wireless region itself. i indicate to the base station all devices that are controlled by the same entity or that interact to configure the wireless region as a collaboration. An eNB, an RRH, an antenna, an RU, an LPN, a point, a transmission / reception point, a transmission point, a reception point, and the like are exemplary embodiments of a base station according to a configuration method of a radio area. ii) may indicate to the base station the wireless region itself that is to receive or transmit signals from the perspective of the user terminal or from a neighboring base station.

Therefore, a base station is collectively referred to as a megacell, a macrocell, a microcell, a picocell, a femtocell, a small cell, an RRH, an antenna, an RU, a low power node (LPN), a point, an eNB, Quot;

Herein, the user terminal and the base station are used in a broad sense as the two transmitting and receiving subjects used to implement the technical or technical idea described in this specification, and are not limited by a specific term or word. The user terminal and the base station are used in a broad sense as two (uplink or downlink) transmitting and receiving subjects used to implement the technology or technical idea described in the present invention, and are not limited by a specific term or word. Here, an uplink (UL, or uplink) means a method of transmitting / receiving data to / from a base station by a user terminal, and a downlink (DL or downlink) .

There are no restrictions on multiple access schemes applied to wireless communication systems. Various multiple access schemes such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), OFDM-FDMA, OFDM- Can be used. An embodiment of the present invention can be applied to asynchronous wireless communication that evolves into LTE and LTE-Advanced via GSM, WCDMA, and HSPA, and synchronous wireless communication that evolves into CDMA, CDMA-2000, and UMB. The present invention should not be construed as limited to or limited to a specific wireless communication field and should be construed as including all technical fields to which the idea of the present invention can be applied.

A TDD (Time Division Duplex) scheme in which uplink and downlink transmissions are transmitted using different time periods, or an FDD (Frequency Division Duplex) scheme in which they are transmitted using different frequencies can be used.

In systems such as LTE and LTE-Advanced, the uplink and downlink are configured on the basis of one carrier or carrier pair to form a standard. The uplink and the downlink are divided into a Physical Downlink Control Channel (PDCCH), a Physical Control Format Indicator CHannel (PCFICH), a Physical Hybrid ARQ Indicator CHannel, a Physical Uplink Control CHannel (PUCCH), an Enhanced Physical Downlink Control Channel (EPDCCH) Transmits control information through the same control channel, and is configured with data channels such as PDSCH (Physical Downlink Shared CHannel) and PUSCH (Physical Uplink Shared CHannel), and transmits data.

On the other hand, control information can also be transmitted using EPDCCH (enhanced PDCCH or extended PDCCH).

In this specification, a cell refers to a component carrier having a coverage of a signal transmitted from a transmission point or a transmission point or transmission / reception point of a signal transmitted from a transmission / reception point, and a transmission / reception point itself .

The wireless communication system to which the embodiments are applied may be a coordinated multi-point transmission / reception system (CoMP system) or a coordinated multi-point transmission / reception system in which two or more transmission / reception points cooperatively transmit signals. antenna transmission system, or a cooperative multi-cell communication system. A CoMP system may include at least two multipoint transmission / reception points and terminals.

The multi-point transmission / reception point includes a base station or a macro cell (hereinafter referred to as 'eNB'), and at least one mobile station having a high transmission power or a low transmission power in a macro cell area, Lt; / RTI >

Hereinafter, a downlink refers to a communication or communication path from a multiplex transmission / reception point to a terminal, and an uplink refers to a communication or communication path from a terminal to a multiplex transmission / reception point. In the downlink, a transmitter may be a part of a multipoint transmission / reception point, and a receiver may be a part of a terminal. In the uplink, the transmitter may be a part of the terminal, and the receiver may be a part of multiple transmission / reception points.

Hereinafter, a situation in which a signal is transmitted / received through a channel such as PUCCH, PUSCH, PDCCH, EPDCCH, and PDSCH is expressed as 'PUCCH, PUSCH, PDCCH, EPDCCH and PDSCH are transmitted and received'.

In the following description, an indication that a PDCCH is transmitted or received or a signal is transmitted or received via a PDCCH may be used to mean transmitting or receiving an EPDCCH or transmitting or receiving a signal through an EPDCCH.

That is, the physical downlink control channel described below may mean a PDCCH, an EPDCCH, or a PDCCH and an EPDCCH.

Also, for convenience of description, EPDCCH, which is an embodiment of the present invention, may be applied to the portion described with PDCCH, and EPDCCH may be applied to the portion described with EPDCCH according to an embodiment of the present invention.

Meanwhile, the High Layer Signaling described below includes RRC signaling for transmitting RRC information including RRC parameters.

The eNB performs downlink transmission to the UEs. The eNB includes a physical downlink shared channel (PDSCH) as a main physical channel for unicast transmission, downlink control information such as scheduling required for reception of a PDSCH, A physical downlink control channel (PDCCH) for transmitting scheduling grant information for transmission in a Physical Uplink Shared Channel (PUSCH). Hereinafter, the transmission / reception of a signal through each channel will be described in a form in which the corresponding channel is transmitted / received.

1 is a diagram illustrating an example of a radio frame structure in the LTE FDD mode.

Referring to FIG. 1, time-frequency resources of the LTE FDD mode are divided into 10-ms radio frames. A 10ms radio frame is divided into 10 1ms long subframes, and a subframe is divided into two 0.5ms slots.

One slot is composed of seven or six symbols on the time axis. In the case of the normal cyclic prefix, seven symbols are included. In the case of the extended cyclic prefix, six symbols .

The transmission of the OFDM symbol is performed on a symbol basis, but the OFDM symbol is affected by the previous symbol while being transmitted through the multipath channel. In order to prevent such OFDM symbol interference, a guard interval longer than the maximum delay spread of the channel is inserted in the beginning of each symbol. The OFDM symbol period is the sum of the effective symbol interval and the guard interval, in which the actual data is transmitted. At the receiving end, the guard interval is removed, and data for the valid symbol interval is taken and demodulated. In the guard interval, to prevent destruction of orthogonality that may occur due to the delay of the subcarrier, the signal of the last interval is copied and inserted into the effective symbol interval, which is called a cyclic prefix (CP).

The length of the normal CP of LTE is about 5 μs, and the length of the extended CP is about 17 μs. An extended CP can be used in a suburban area where the cell radius is large and the delay spread is long. The extended CP is longer than the normal CP, so the number of symbols is reduced from 7 to 6.

One slot is composed of a plurality of resource blocks (RBs) in the frequency domain, and one slot may include a minimum of 6 to a maximum of 110 RBs.

A PBCH (Physical Broadcasting CHannel)

In general, in a mobile communication system, basic system information is transmitted using a broadcast channel. In LTE, broadcasting system information includes a master information block (MIB) and a system information block (SIB). The MIB is transmitted using a PBCH and the SIB is transmitted using a downlink shared channel.

The PBCH maps to 72 subcarriers in the center in the frequency band of the OFDM signal

The UE can detect the PBCH by checking only the 72 subcarriers located at the center even if the UE initially knows no information about the system bandwidth.

2 is a diagram for explaining a structure of a PBCH.

Referring to FIG. 2, the existing PBCH is located only in the second slot of the first subframe. That is, only slot number 1 is allocated. The PBCH is composed of 4 OFDM symbols, and 6 resource blocks are allocated on the PBCH frequency axis up and down around DC (frequency 0) at all times.

Since the size of the MIB is 14 bits and it is repeated every 40 ms, the data rate of the PBCH is 350 bps. A 16-bit CRC is added to the MIB, and after coding, it is divided into four subsets, each of which is transmitted using four different radio frames in a 40 ms transmission period. If the SIR (Signal to Interference Ratio) characteristic of the wireless channel is good, the terminal can detect the MIB even if only a part of the four radio frames is demodulated, so that it is not necessary to receive the remaining radio frames. If the SIR characteristics are not good, the MIB is detected by soft combining the radio frames after receiving the additional radio frames.

The base station of the present invention can repeatedly transmit the PBCH for the MTC terminal. For example, when a specific cycle (for example, 40 ms) cycle (The repetition burst within the 40ms PBCH cycle) in one of the following ways.

For example, the base station can repeat transmission (Repetition in SF # 0) in subframe # 0 (SF # 0).

Alternatively, the base station may repeat transmission (Repetition in SF # 0) in each sub-frame # 0 of odd frames and / or repetition in SF # 5 in each sub-frame # 5.

Alternatively, the base station may repeat transmission (Repetition in SF # 0) and / or repetition in one other subframe in subframe # 0 (SF # 0) of all frames.

Alternatively, the base station may repeat transmission (Repetition in SF # 0) in subframe # 0 (SF # 0) of all frames and / or repetition in 3 other subframes in three different subframes.

On the other hand, certain resource elements (REs) may be excluded from the PBCH repetitive transmission.

On the other hand, user data and MIB repeat transmission may not be transmitted in the same PRBs. In other words, PDSCH and PBCH iterative transmissions can be transmitted in the same PRBs without multiplexing. The PBCH does not transmit user data to the PRBs repetitively transmitting.

On the other hand, in a 40ms cycle, the transmission configuration (transmission of 40ms cycles) is always repeated in all 40ms cycles or dynamically on / off repetitions every 40x ms cycles (x is a natural number greater than 1) on a per 40 x ms cycle basis, or repetition based on pattern (s) across a given number of cycles based on the pattern at a given number of cycles.

FIG. 3 is a diagram for explaining PBCH repeat transmission according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 3, the base station 300 may perform a setting for repeatedly transmitting the PBCH based on at least one of the methods described above (S310). The base station can repeatedly allocate the PBCH transmission resources for transmitting the PBCH to the specific subframe as described above to set up the repeated transmission.

The method of repeatedly allocating transmission resources to each subframe may be assigned to a specific subframe of a specific frame or to a specific subframe of an odd or even frame as described above. In addition, it is possible to allocate each transmission resource according to each iteration method described above to set iterative transmission.

Meanwhile, when the setup for repeatedly transmitting the PBCH is completed, the base station can perform the set PBCH iterative transmission (S320). That is, the base station can repeatedly transmit the PBCH for the MTC terminal 310. The PBCH information to be transmitted repeatedly may be the same or may be different from each other, but it is possible to acquire the PBCH information when performing soft combining on the repeated PBCH information.

The MTC terminal 310 receives the PBCH repeatedly transmitted according to the repetition setting described above, and performs PBCH decoding by combining the repeatedly transmitted PBCH (S330). Accordingly, the MTC mobile station can soft-combine a plurality of PBCHs repeatedly received, perform decoding, and acquire the corresponding information.

Hereinafter, the PRACH transmission / reception will be described in the case of the MTC terminal.

Physical Random Access Channel (PRACH)

4 is a diagram for explaining the structure of the PRACH.

Referring to FIG. 4, the PRACH is a channel for transmitting a random access preamble transmitted from a mobile station to a base station in a random access procedure. PRACH is multiplexed with PUSCH and PUCCH on time and frequency. The PRACH time-frequency resources are allocated in the PUSCH region and are repeated periodically.

The PRACH preamble consists of OFDM symbols and is constructed by adding the end part of the preamble sequence to the preamble before the CP.

On the other hand, under the assumption that the timing advance is 0, the UE matches the start point of the random access preamble with the start point of the uplink subframe. Taking transmission delay into account, GT (Guard Time) is required, so the preamble length is shorter than the PRACH slot length.

Four types of PRACH preamble formats are defined for the FDD mode, and each format is defined according to the sequence and the length of the CP.

In the case of the MTC terminal, the random access procedure with the base station can be performed using the PRACH described above. However, since the MTC terminal needs to expand its coverage as described above, it is necessary to repeatedly transmit the PRACH. Therefore, it is necessary to use existing PRACH formats or to define a new PRACH format when transmitting the PRACH repeatedly.

The MTC terminals of the present invention and existing terminals can share the same time / frequency resources. In this case, the MTC terminals can multiplex with existing terminals using a Code Division Multiple (CDM) scheme. At this time, repetition level (s) can be multiplexed within the shared time / frequency resources.

Additional time / frequency resource region (s) may be defined for the MTC terminals. At least CDM can be allowed in the new area.

On the other hand, frequency hopping can be allowed in repetitive transmission of PRACH.

Or a specific repetition level may be defined and set for repeated transmissions to MTC terminals.

That is, the MTC terminal can transmit the PRACH repeatedly at a specific number of times. If the MTC terminal repeatedly transmits the PRACH at a specific number of times but fails to receive the random access response (RAR) for the PRACH, it can change the repetition level and retransmit it. Alternatively, the transmission power may be ramped up and retransmitted. The transmit power may be increased stepwise or may be increased analogously. For example, if the MTC terminal increases the number of repetitions in the order of once, twice, and three, but can not receive the RAR, the PRACH can be retransmitted by improving the transmission power to a certain level. In this case, the repetition times may be sequentially increased in the order of once, twice, and three times in accordance with the repetition level.

Or a repetition level determined according to the number of repetitions may be set, and the PRACH may be transmitted with a different repetition number by changing each repetition level.

For example, the specified maximum numbers of levels of PRACH repetition levels may be three. In other words, the PRACH repetition level may be one of, for example, 1, 2, or 3. A specified maximum value of PRACH repetition levels of 3 does not include a " zero coverage extension ".

The number of repetitions per level may be a value that can be set. In this case, the setting value of one repetition transmission can be defined as 1 attempt (1 attempt = configured number of repetitions). The number of repetitions for each level can be fixed or changed at each setting. At this time, the repetition level and the number of PRACH repeat transmissions can form a functional relationship. If the repetition level is 1 and the PRACH is repeated n times, the number of PRACH repeated transmissions of the repetition level m may be m * n. For example, repetition level 1 repetitively transmits PRACH 5, repetition level 2 repetitively transmits PRACH 10, and repetition level 3 repetitively transmits PRACH 15.

In addition, power ramping may be supported in repetitive PRACH transmissions.

If the terminal does not receive a random access response (RAR) after one attempt (set value of one repetition transmission), it can move to the next level (e.g., the number of repetitive transmissions from 5 to 10, or 10 to 15). How many attempts are allowed at the top level can be set by the base station. If the terminal does not receive a random access response (RAR) after one attempt (one set of repetition transmissions), then power ramping when moving to the next level (for example, the number of repetitive transmissions from 5 to 10, or 10 to 15) May be preceded, followed, or concurrent.

In the embodiment, when the PRACH repeated transmission and the power ramping are concurrently performed, if the UE fails to perform the step of receiving the RAR from the base station after repeatedly transmitting the PRACH preamble, the repetitive transmission of the PRACH preamble is moved to the next level Power ramping may also be performed.

The initial level for the contention based random access procedure may be (1) started at the lowest level, or may be defined based on measurement or other scheme, or (2) RRC connected mode (dedicated RRC signaling).

In short, the MTC terminal repeatedly transmits the PRACH according to the preset repetition times. Thereafter, when the random access fails, the PRACH transmission level can be changed at the next repetition level, and the PRACH can be repeatedly transmitted at the repetition times defined in the next repetition level.

Alternatively, if the random access fails, the MTC terminal may change the transmission power to the next level and transmit the PRACH repeatedly with the repetition times defined by the next transmission power.

Alternatively, the MTC terminal may repeatedly transmit the PRACH while sequentially changing the repetition level to the set maximum level when the random access fails, and may transmit the PRACH at the next transmission power when the transmission fails even at the maximum repetition level. That is, it is possible to sequentially change the repetition level and perform repetitive transmission by ramping up the transmission power when the repetition transmission fails even at the maximum repetition level. In this case, the repetition level may be changed back to the first repetition level to perform repetitive transmission, and transmission may be performed at the repetition level.

PDCCH / PDSCH

The PDCCH is a channel for transmitting DCI (Downlink Control Information). DCI includes resource allocation information and other control information for a terminal or a terminal group. In general, a plurality of PDCCHs can be transmitted in one subframe.

Each PDCCH is transmitted using one or a plurality of CCEs (Control Channel Elements). One CCE is composed of 9 REGs, and four QPSK symbols are mapped to one REG. Since the RE allocated to the reference symbol is not included in the REG, the total number of REGs depends on whether or not a cell-specific RS (Reference Signal) exists.

There are four types of PDCCH formats, and the number of CCEs required for each format is different.

The number of CCEs used for transmission of a particular PDCCH is determined by the eNodeB according to the channel conditions. For example, in the case of a terminal near an eNodeB, only one CCE is sufficient because the characteristics of the downlink channel are good. However, when the terminal has poor channel characteristics at the cell boundary, eight CCEs are required. In addition, the power level of the PDCCH is also adjusted according to the channel characteristics.

The content of the control channel message included in the DCI is related to the operation mode of the system. For example, when the system does not support MIMO or the terminal is set to a transmission mode that does not include MIMO, it is not necessary to transmit parameters required only for MIMO transmission. The number of bits required for resource allocation depends on the bandwidth of the system, and the resulting message size also depends on the system bandwidth.

A 16-bit CRC is added to the PDCCH, and the UE can detect whether there is an error in the PDCCH using the CRC. In addition, the UE needs to check whether the received PDCCH corresponds to one of a plurality of UEs, which can be implemented by adding a discriminator to the payload of the PDCCH. There is a method of scrambling the CRC with the terminal distinguisher in order to determine whether the terminal is the terminal corresponding to itself. This method has an advantage that it is unnecessary to add a distinguisher to the payload

The EPDCCH is a channel for transmitting control information transmitted through the PDCCH in the data area. Therefore, the control channel transmitted in the data area may be called EPDCCH (Extended PDCCH or Enhanced PDCCH), but is not limited thereto.

In the case of the EPDCCH newly introduced in the 3GPP LTE / LTE-A release 11 and its follow-up systems, unlike the legacy PDCCH, it is transmitted through the PDSCH region and a terminal set to receive DCI (Downlink Control Information) through the corresponding EPDCCH (K = 1 or 2) of EPDCCH sets each consisting of M PRBs (a group of M PRBs) (M = 2, 4, or 8) . Also, each EPDCCH set set for an arbitrary terminal may have a different K value.

Depending on the EPDCCH transmission type, the EPDCCH set may be a localized type or a distributed type, where M is 1 or 2n (n = 1, 2, 3, 4, 5). ≪ / RTI > While M can be 2, 4, 8, 16 in the decentralized form, but is not limited thereto.

K sets of EPDCCHs can be allocated for one terminal. Since each set of EPDCCHs is a distributed type or a centralized type, the number of distributed types of EPDCCH and KD distributed for one terminal is KL Type EPDCCH can be allocated. That is, KL + KD = K can be obtained. For example, if K is 2, KL can be one of 0, 1, 2, and KD can be one of 2,1, 0.

An EREG (Enhanced REG) / ECCE (Enhanced CCE) may be introduced into the EPDCCH corresponding to the concept of REG and CCE of the conventional PDCCH for EPDCCH transmission resource mapping for an arbitrary terminal.

According to the newly introduced EREG / ECCE, not only a frame structure type, a subframe configuration, a CP (Cyclic Prefix) length but also a legacy PDCCH control are set for one PRB pair constituting each EPDCCH set A total of 16 EREGs from EREG # 0 to EREG # 15 are configured in the corresponding PRB pair irrespective of whether or not the reference signal (for example, CRS, CSI-RS, PRS, etc.) can do.

Specifically, for a normal CP for one PRB pair constituting an arbitrary EPDCCH set, 16 numbers are allocated to 144 REs excluding 24 REs for a DM-RS among a total of 12 x 14 = 168 REs EREG indexing can be done from 0 to 15 in frequency first and then time manner. Likewise, in the case of the extended CP, for the 128 REs except for the 16 REs for the DM-RS out of the 12 x 12 = 144 REs constituting one PRB pair, 16 numbers are allocated in the frequency first and then time manner, the EREG can be indexed from 0 to 15.

In the case of the MTC terminal according to the present invention, control information can be received through the EPDCCH. Therefore, hereinafter, the PDCCH and the EPDCCH, which are channels for transmitting control information, and the timing of the PDSCH indicated by the control information included in the corresponding channel, do. Hereinafter, the downlink control channel is referred to as (E) PDCCH in a sense including both PDCCH and EPDCCH. Therefore, (E) PDCCH may mean PDCCH or EPDCCH.

In the present invention, when the (E) PDCCH is repeatedly received for the MTC terminal, the PDCCH timing is suggested regarding the relation of the (E) PDCCH timing with respect to the PDSCH timing with respect to when the PDSCH is indicated. The timing information must be known to the MTC terminal, may not be set by the upper layer parameter that is deduced for this purpose only, and (E) may not be indicated by the PDCCH.

Generally, in the case of the existing PDSCH, the PDCCH is transmitted after the PDCCH is transmitted. The PDCCH includes scheduling information for the PDSCH and provides information for the UE to receive data information using the PDSCH.

However, the (E) PDCCH for the MTC terminal of the present invention is repeatedly transmitted. Therefore, the PDSCH may not be transmitted before the end of the repeated transmission of the (E) PDCCH. That is, PDCCH can be repeatedly transmitted after (E) PDCCH repeated transmission.

At this time, the base station needs to share information on the starting sub-frame repeatedly transmitted by the PDSCH with the MTC terminal. This is because the MTC terminal can perform accurate decoding by knowing at what point the repetition of the (E) PDCCH ends and at which point the PDSCH is transmitted.

Therefore, the PDSCH repetition start subframe of the present invention can start at a subframe n + k (a natural number where k> 0) if the subframe n is the last subframe of the (E) PDCCH repetition transmission.

At this time, the k value may have a fixed value irrespective of the number of (E) PDCCH repetitive transmissions, and may have a correlation with the number of (E) PDCCH repetitive transmissions. For example, the larger the number of (E) PDCCH repetition transmissions, the greater the value of k. (E) The larger the number of iterative transmissions of the PDCCH (E), the longer the time to decode the PDCCH through soft combining or chase combining, so that the value of k can be increased.

(E) If the number of repetitive transmissions of the PDCCH is sufficiently large, it is possible to decode the (E) PDCCH before the subframe n repeatedly transmitting the last (E) PDCCH. Lt; / RTI >

If the subframe n is the last subframe of the PDCCH repetitive transmission, the base station performs the repeated transmission of the (E) PDCCH and transmits PDSCH in the subframe n + k (k> 0) ≪ / RTI > The above-described k value may have a fixed value irrespective of the number of (E) PDCCH repetitive transmissions, and may have a correlation with the number of (E) PDCCH repetitive transmissions.

5 is a diagram illustrating an example of a method of blind decoding a PDCCH or an EPDCCH and receiving a PDSCH by the MTC terminal.

In the example of FIG. 5, the BS repeatedly transmits one DCI through four subframes SF # 0 (Subframe Number # 0) to SF # 3 in consideration of the channel condition of the MTC terminal. In addition, the base station repeatedly transmits the same data through four subframes SF # 3 to SF # 6 in consideration of the channel condition of the MTC terminal. When the CRC check is successful as a result of soft combining the received values of the DCI transmitted in SF # 0 to SF # 3 and blind decoding the MTC UE, the MTC UE confirms the scheduling information of the PDSCH included in the DCI . The MTC terminal soft-combines the reception values of the data transmitted in SF # 3 to SF # 6 to perform decoding.

In the case of repetition of the corresponding channel in the PDCCH or EPDCCH transmission for the MTC terminal, in order to successfully decode in the corresponding MTC terminal, definitions of the PDCCH and the PDCCH start subframe including the repetition count and repetition are defined need.

The MTC terminal according to an embodiment of the present invention may support (E) PDCCH scheduling PDSCH into a UE-specific search space. (E) PDCCH repeat transmission with multiple levels can also be supported. From the UE perspective, the possible starting subframes of the (E) PDCCH iterative transmission may be limited to a subset of subframes. That is, it constitutes a subset of specific subframes, and (E) PDCCH iterative transmission in one of these specific subframes can be started.

The method of constructing a subset of particular subframes may vary.

For example, a fixed subset may be configured according to the DCI format of the (E) PDCCH. That is, a separate subset may be configured according to the DCI format of the downlink scheduling and the DCI format of the uplink grant. At this time, the same subset can be configured according to the DCI formats (DCI formats 1, 1a, 1b, 2, and 3) of the downlink scheduling, or different subsets can be configured. Similarly, the same subset can be configured according to the DCI (DCI format 0, 4) of the uplink grant, or different subsets can be configured.

As another example, a subset may be configured according to the number of repetitive transmissions of the (E) PDCCH (repetition transmission level). That is, the larger the number of repetitive transmissions (repetition transmission level) of the (E) PDCCH, the smaller the number of subframes constituting the subset. On the contrary, as the number of repetitive transmissions (repetition transmission level) of the (E) PDCCH is smaller, the number of subframes constituting the subset can be increased. The number of subframes constituting the subset can be made larger in proportion to the number of repetitive transmissions of the (E) PDCCH as opposed to the above.

Repetitive transmission of PUCCH on periodic CSI is not supported. The PUCCH phase periodic CSI may not be repeatedly transmitted. ACK / NACK on PUCCH is supported and ACK / NACK setting can be considered. Dedicated SR is supported but does not define a new format for PUCCH iterative transmission to SR.

PDSCH repeat transmission with multiple subframes may be supported. Multiple repeat transmission levels can be specified in the time domain.

Hereinafter, operations of the base station and the terminal according to the present invention will be described in more detail with reference to the drawings.

6 is a view for explaining an operation of a base station according to an embodiment of the present invention.

A base station according to an embodiment of the present invention is a method for a base station to transmit a control channel, the method comprising: repeatedly transmitting a control channel including control information; and repeating the transmission of the control channel based on information on a sub- And repeatedly transmitting a downlink data channel (PDSCH).

Referring to FIG. 6, the BS repeatedly transmits a control channel including control information to the MTC terminal (S610). The control information may include downlink scheduling information or uplink grant information. Further, the control channel including the control information includes the above-described PDCCH or EPDCCH. Therefore, the control channel may be a channel transmitted to the mobile station, including control information regardless of the transmission mode.

Meanwhile, the base station may repeatedly transmit the downlink data channel (PDSCH) based on the information on the subframe in which the control channel to be transmitted ends (S620).

The downlink control channel may be transmitted after a subframe in which the repeatedly transmitted control channel ends is completed. That is, when the subframe in which the control channel ends is n, the downlink control channel can be transmitted starting from n + k (a natural number with k> 0) subframe. In other words, the downlink control channel can be repeatedly transmitted after a certain subframe after the end of the subframe in which the control channel is repeatedly transmitted. In the present invention, the downlink data channel refers to a channel for transmitting data information and may mean, for example, a PDSCH.

On the other hand, the k value may be a value fixedly set regardless of the number of repetitive transmissions of the control channel. That is, the value of k may be a value fixed to a value that is set irrespective of the base station and the MTC terminal. Alternatively, the base station may inform the MTC terminal of information on the k value by upper layer signaling.

As another example, the k value may be a value determined according to the number of repetitive transmissions of the control channel. That is, the k value may be dynamically determined depending on the repetition number of times or repetition level of the control channel being repeated. For example, the value of k may be increased as the number of repeated transmissions of the control channel increases. Or the k value may be reduced as the number of repeated transmissions of the control channel increases. That is, the value k can be increased or decreased according to the number of repetitive transmissions of the control channel. The k value may be increased or decreased corresponding to the number of repetitive transmissions, or one k value may correspond to the repetition number of transmissions.

In another embodiment, the control channel of the present invention starts repetitive transmission in a particular subframe, wherein a particular subframe constitutes a subset of at least two subframes, and a particular subframe comprises a subset of subframes Frame. ≪ / RTI > That is, a subframe in which repetitive transmission of a control channel starts is composed of a subset, which is a group of at least two subframes, and a subframe in which repeated transmission of a control channel is started may be determined to be one of subframes included in the subset.

The subset may be configured as a separate subset according to the DCI format of the downlink scheduling and the DCI format of the UL grant.

In addition, the number of subframes constituting the save set can be determined based on the number of repetitive transmissions of the control channel. For example, if the number of repeated transmissions of the control channel increases, the number of subframes constituting the subset may be determined to decrease. As another example, if the number of repetitive transmissions of the control channel decreases, the number of subframes constituting the subset may be determined to increase.

In addition, the base station can perform various repetitive transmission methods described with reference to FIGS. 1 to 5 described above.

7 is a diagram for explaining operations of a terminal according to an embodiment of the present invention.

A method for receiving a control channel in a terminal according to an embodiment of the present invention includes the steps of repeatedly receiving a control channel including control information and repeatedly receiving a control channel based on information on a sub- And repeatedly receiving a Link Data Channel (PDSCH).

Referring to FIG. 7, the MTC terminal of the present invention may include a step of repeatedly receiving a control channel including control information (S710). The control information may include downlink scheduling information or uplink grant information. Further, the control channel including the control information includes the above-described PDCCH or EPDCCH. Therefore, the control channel may refer to a channel received by the terminal including control information irrespective of the transmission mode.

In addition, the MTC terminal of the present invention may include repeatedly receiving a downlink data channel (PDSCH) based on information on a sub-frame in which a control channel repeatedly transmitted ends.

The downlink control channel may be received after the end of the subframe in which the repeatedly transmitted control channel ends. That is, if the subframe in which the control channel ends is n, the downlink control channel can be received and started in the (n + k) th subframe (n + k). In other words, the downlink control channel can be repeatedly received after a certain subframe after the end of the subframe in which the control channel is repeatedly received. In the present invention, the downlink data channel refers to a channel for transmitting data information and may mean, for example, a PDSCH.

On the other hand, the k value may be a value fixedly set regardless of the number of repetitive transmissions of the control channel. That is, the value of k may be a value fixed to a value that is set irrespective of the base station and the MTC terminal. Alternatively, the base station may inform the MTC terminal of information on the k value by upper layer signaling.

As another example, the k value may be a value determined according to the number of repetitive transmissions of the control channel. That is, the k value may be dynamically determined depending on the repetition number of times or repetition level of the control channel being repeated. For example, the value of k may be increased as the number of repeated transmissions of the control channel increases. Or the k value may be reduced as the number of repeated transmissions of the control channel increases. That is, the value k can be increased or decreased according to the number of repetitive transmissions of the control channel. The k value may be increased or decreased corresponding to the number of repetitive transmissions, or one k value may correspond to the repetition number of transmissions.

In another embodiment, the control channel of the present invention starts repetitive transmission in a particular subframe, wherein a particular subframe constitutes a subset of at least two subframes, and a particular subframe comprises a subset of subframes Frame. ≪ / RTI > That is, a subframe in which repetitive transmission of a control channel starts is composed of a subset, which is a group of at least two subframes, and a subframe in which repeated transmission of a control channel is started may be determined to be one of subframes included in the subset.

The subset may be configured as a separate subset according to the DCI format of the downlink scheduling and the DCI format of the UL grant.

In addition, the number of subframes constituting the save set can be determined based on the number of repetitive transmissions of the control channel. For example, if the number of repeated transmissions of the control channel increases, the number of subframes constituting the subset may be determined to decrease. As another example, if the number of repetitive transmissions of the control channel decreases, the number of subframes constituting the subset may be determined to increase.

In addition, the MTC terminal can perform various iterative reception methods described with reference to FIGS. 1 to 5 described above.

8 is a diagram illustrating a configuration of a base station according to an embodiment of the present invention.

The base station 800 according to an exemplary embodiment of the present invention repeatedly transmits a control channel including control information including a control information to a specific subframe starting from a control unit 810 for determining a specific subframe in which repeated transmission of a control channel is started , And a transmitter 820 for repeatedly transmitting a downlink data channel (PDSCH) based on information on a sub-frame over which a control channel repeatedly transmitted ends. The controller 810 controls the sub- A specific subframe can be determined as one of the subframes included in the subset.

8, a base station 800 according to an exemplary embodiment of the present invention includes a controller 810, a transmitter 820, and a receiver 830.

The control unit 810 controls the overall operation of the base station for repeated transmission of the control channel and downlink data channel repetition transmission, which are necessary for carrying out the present invention. In addition, the controller 810 may determine a particular subframe in which repeated transmission of the control channel starts. In addition, when a particular subframe forms a subset of at least two subframes, the controller 810 may determine a specific subframe among the subframes included in the subset.

The transmitter 820 may repeatedly transmit a control channel including control information starting from a specific subframe and repeatedly transmit the downlink data channel based on information on a subframe in which a repeatedly transmitted control channel ends.

In addition, the transmitting unit 820 and the receiving unit 830 are used for transmitting / receiving signals, messages, and data necessary for performing the above-described present invention to / from the terminal. In addition, the base station 800 includes a configuration capable of performing the above-described base station operations of Figs. 1 to 6, respectively.

9 is a diagram illustrating a configuration of a user terminal according to an embodiment of the present invention.

The terminal 900 according to an exemplary embodiment of the present invention includes a receiver 930 for repeatedly receiving a control channel including control information and a control unit 910 for decoding the control channel to obtain control information, 930 may repeatedly receive the downlink data channel based on the information on the subframe where the control channel repeatedly transmitted ends.

9, a user terminal 900 according to an exemplary embodiment of the present invention includes a receiver 930, a controller 910, and a transmitter 9200.

The receiving unit 930 receives downlink control information, data, and a message from the base station through the corresponding channel. The receiving unit 930 may repeatedly receive the control channel including the control information, and repeatedly receive the downlink data channel based on the information on the sub-frame in which the control channel repeatedly transmitted ends.

In addition, the controller 910 can control the overall operation of the terminal related to the repetitive transmission of the control channel and the downlink data channel, which are necessary to perform the above-described present invention.

The transmitter 920 transmits uplink control information, data, and a message to the base station through the corresponding channel.

Each of the other terminal configurations can perform all the operations of the terminal of the present invention described with reference to Figs. 1 to 7.

The present invention provides an effect of enabling a MTC terminal with a wider coverage to efficiently communicate with a base station by defining a subframe rule for repeated transmission of a physical channel for the MTC terminal.

The present invention also provides a method and apparatus for effectively transmitting and receiving a downlink signal by defining a relationship between transmission and reception for PBCH, PRACH, PDSCH, PDCCH, and EPDCCH as physical channels for the MTC terminal .

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

Claims (23)

A method for a base station to transmit a control channel,
Repeatedly transmitting a control channel including control information; And
And repeatedly transmitting the downlink data channel based on the information on the sub-frame over which the repeatedly transmitted control channel ends. The method according to claim 1,
Wherein the control channel comprises:
RTI ID = 0.0 > PDCCH < / RTI > and EPDCCH. The method according to claim 1,
The downlink data channel includes:
Wherein the transmission starts in n + k subframes (k is a natural number) when the subframe in which the repeatedly transmitted control channel ends is n. The method of claim 3,
The k-
Wherein the control channel is set to a fixed value regardless of the number of repetitive transmissions of the control channel. The method of claim 3,
The k-
And a value determined according to the number of repetitive transmissions of the control channel. 6. The method of claim 5,
The k-
And increases as the number of repeated transmissions of the control channel increases. 6. The method of claim 5,
The k-
And decreasing as the number of repeated transmissions of the control channel increases. The method according to claim 1,
Wherein the control channel comprises:
Wherein the repetitive transmission starts in a specific subframe, the specific subframe comprises a subset of at least two subframes, and the specific subframe is one of subframes included in the subset. 9. The method of claim 8,
The subset includes:
And the DCI format of the downlink scheduling and the DCI format of the uplink grant. 9. The method of claim 8,
Wherein the number of subframes constituting the subset is determined based on the number of repeated transmissions of the control channel. 11. The method of claim 10,
Wherein when the number of repeated transmissions of the control channel increases, the number of subframes constituting the subset is determined to decrease. 11. The method of claim 10,
Wherein the number of subframes constituting the subset is determined to increase when the number of repeated transmissions of the control channel decreases. A method for a terminal to receive a control channel,
Repeatedly receiving a control channel including control information; And
And repeatedly receiving a downlink data channel based on information on the sub-frame over which the repeatedly transmitted control channel ends. 14. The method of claim 13,
Wherein the control channel comprises:
RTI ID = 0.0 > PDCCH < / RTI > and EPDCCH. 14. The method of claim 13,
The downlink data channel includes:
Wherein the transmission starts in n + k subframes (k is a natural number) when the subframe in which the repeatedly transmitted control channel ends is n. 16. The method of claim 15,
The k-
Wherein the control channel is fixed regardless of the number of repetitive transmissions of the control channel or is determined according to the number of repetitive transmissions of the control channel. 14. The method of claim 13,
Wherein the control channel comprises:
Wherein the repetitive transmission starts in a specific subframe, the specific subframe comprises a subset of at least two subframes, and the specific subframe is one of subframes included in the subset. 18. The method of claim 17,
The subset includes:
And the DCI format of the downlink scheduling and the DCI format of the uplink grant. 18. The method of claim 17,
Wherein the number of subframes constituting the subset is determined based on the number of repeated transmissions of the control channel. 18. The method of claim 17,
Wherein when the number of repeated transmissions of the control channel increases, the number of subframes constituting the subset is determined to decrease. 18. The method of claim 17,
Wherein the number of subframes constituting the subset is determined to increase when the number of repeated transmissions of the control channel decreases. A base station for transmitting a control channel,
A control unit for determining a specific subframe in which repeated transmission of the control channel starts; And
And a transmitter for repeatedly transmitting the control channel including the control information starting from the specific subframe and repeatedly transmitting the downlink data channel based on the information on the subframe in which the repeatedly transmitted control channel ends, ,
Wherein the controller determines the specific subframe among the subframes included in the subset when the specific subframe comprises a subset of at least two subframes. A terminal for receiving a control channel,
A receiver repeatedly receiving a control channel including control information; And
And a control unit for decoding the control channel to obtain the control information,
Wherein the receiver repeatedly receives a downlink data channel based on information on a sub-frame over which the repeatedly transmitted control channel ends.

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