KR20160037757A

KR20160037757A - Methods for transmitting downlink data and Apparatuses thereof

Info

Publication number: KR20160037757A
Application number: KR1020150130913A
Authority: KR
Inventors: 강승현; 박규진; 최우진
Original assignee: 주식회사 케이티
Priority date: 2014-09-26
Filing date: 2015-09-16
Publication date: 2016-04-06

Abstract

The present invention relates to a method and apparatus for transmitting and receiving downlink data in a wireless communication system. And more particularly, to a method and apparatus for repeatedly transmitting and receiving downlink data and downlink control information for an MTC terminal located at an improved coverage compared to a general terminal. In particular, the present invention provides a method for receiving downlink data by a MTC (Machine Type Communication) terminal, comprising the steps of: receiving downlink control information (Downlink Control) including resource allocation information of downlink data Information, DCI) in a first time domain, repeatedly receiving, in a second time domain, second downlink control information including resource allocation information of downlink data applied to a UE, and 1) checking downlink data commonly applied to a plurality of terminals based on the downlink control information, and identifying downlink data to be applied for terminal identification based on the second downlink control information .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for transmitting downlink data,

The present invention relates to a method and apparatus for transmitting and receiving downlink data in a wireless communication system. And more particularly, to a method and apparatus for repeatedly transmitting and receiving downlink data and downlink control information for an MTC terminal located at an improved coverage compared to a general terminal.

Machine Type Communication (MTC) or Machine to Machine (M2M) is 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 "MTC" may refer to a form of data communication involving one or more of such 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 The mobile terminal having the MTC function is considered as a type of machine.

The MTC terminal can be installed in a place where the radio wave environment is worse than that of a general terminal. Therefore, the coverage of the MTC terminal should be improved to 20 dB or more in comparison with the coverage of the general terminal.

On the other hand, in the case of the MTC terminal, the bandwidth of radio resources may be limited. That is, the bandwidth of the radio resource for the MTC terminal may be relatively limited as compared with the bandwidth of the general LTE terminal.

Therefore, the MTC terminal may not normally receive the downlink control information of the general LTE terminal.

In the background described above, the present invention proposes a method and apparatus for normally transmitting / receiving control information and data even in an environment where the radio resource bandwidth of the MTC terminal is limited.

According to an aspect of the present invention, there is provided a method of receiving downlink data by a MTC (Machine Type Communication) terminal, the method comprising: The method includes receiving repeatedly downlink control information (DCI) in a first time domain, and receiving second downlink control information including resource allocation information of downlink data applied to a UE in a second time domain A step of repeatedly receiving and downlink data commonly applied to a plurality of terminals based on the first downlink control information, and checking downlink data applied to the terminal based on the second downlink control information The method comprising the steps of:

According to another aspect of the present invention, there is provided a method for transmitting downlink data in a base station, including the steps of: receiving first downlink control information (DCI) including resource allocation information of downlink data commonly applied to a plurality of terminals; Allocating radio resources of second downlink control information including resource allocation information of downlink data to be specifically applied, transmitting first downlink control information in a first time domain, and transmitting second downlink control information In a second time domain.

According to another aspect of the present invention, there is provided a MTC (Machine Type Communication) terminal for receiving downlink data, including first downlink control information including downlink data resource allocation information commonly applied to a plurality of terminals, DCI) in a first time domain and repeatedly receives second downlink control information including resource allocation information of downlink data applied to the UE in a second time domain, And a controller for checking downlink data commonly applied to a plurality of terminals based on the control information and identifying downlink data applied to the terminal based on the second downlink control information.

In addition, the present invention provides a base station for transmitting downlink data, comprising: first downlink control information (DCI) including resource allocation information of downlink data commonly applied to a plurality of terminals; A control unit for allocating radio resources of second downlink control information including resource allocation information of downlink data to be applied, and a controller for transmitting first downlink control information in a first time domain and transmitting second downlink control information in a second time domain, And a transmitter for transmitting in a time domain.

According to the present invention described above, the MTC terminal can normally transmit and receive control information and data even in an environment where the radio resource bandwidth is limited.

1 is a diagram illustrating an example of a PDCCH coding method
2 is a diagram for explaining a method of identifying downlink data using downlink control information.
3 is a diagram illustrating a method of decoding a PDSCH by the MTC terminal.
4 is a diagram for explaining a method of allocating radio resources by classifying time zones of downlink control information and downlink data according to the present invention.
5 is a diagram illustrating an example of downlink control information and downlink data transmitted in a first time domain according to the present invention.
6 is a diagram for explaining the operation of the MTC terminal according to an embodiment of the present invention.
7 is a view for explaining an operation of a base station according to another embodiment of the present invention.
8 is a diagram illustrating a configuration of a user terminal according to another embodiment of the present invention.
9 is a diagram illustrating a configuration of a base station according to another 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 even though 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.

In other words, the MTC terminal may refer to a newly defined 3GPP Release 13 low cost (or low complexity) UE category / type for performing LTE-based MTC-related operations. Alternatively, the MTC terminal may support the enhanced coverage over the existing LTE coverage or the UE category / type defined in the existing 3GPP Release 12 or lower that supports low power consumption, or the newly defined Release 13 low cost (or low complexity ) UE category / type.

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, in the present specification, a base station or a cell has a comprehensive meaning indicating a part or function covered by BSC (Base Station Controller) in CDMA, Node-B 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) the device itself providing a megacell, macrocell, microcell, picocell, femtocell, small cell in relation to the wireless region, or ii) indicating 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 base station, collectively referred to as a megacell, macrocell, microcell, picocell, femtocell, small cell, RRH, antenna, RU, low power node do.

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 transmit and receive 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 multipoint transmission / reception point to a terminal, and an uplink refers to a communication or communication path from a terminal to a multiple 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 PDSCH, and uplink data channel 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.

Machine Type Communication (MTC) is defined as communication between a device and an object without human intervention. From the 3GPP perspective, "machine" means an entity that does not require direct manipulation or intervention by a person, and "MTC" is defined as a form of data communication involving one or more of these machines. A typical example of a machine is a smart meter equipped with a mobile communication module, a vending machine, etc. Recently, however, depending on a user's location or situation, A mobile terminal having an MTC function is considered as a form of a machine.

As the LTE network spreads, mobile operators want to minimize the number of Radio Access Terminals (RATs) to reduce network maintenance costs. However, conventional MTC products based on a GSM / GPRS network are increasing, and MTC using a low data rate can be provided at low cost. Therefore, there is a problem in that two RATs must be operated respectively, since LTE network is used for general data transmission and GSM / GPRS network is used for MTC. Therefore, Of the total revenue.

In order to solve this problem, it is necessary to replace a cheap MTC terminal using a GSM / EGPRS network with an MTC terminal using an LTE network, and various requirements for lowering the price of the LTE MTC terminal are required for the 3GPP RAN WG1 standard conference . In addition, the 3GPP standards conference is preparing a document (TR 36.888) describing various functions that can be provided to satisfy the above requirements.

In order to support the low-cost LTE MTC terminal, the main items related to the change of the physical layer standard currently being discussed in the 3GPP include technologies such as narrow band support, single RF chain, Half duplex FDD and long DRX (Discontinued Reception). However, the above methods, which are considered for lowering the price, can reduce the performance of the MTC terminal as compared with the conventional LTE terminal.

In addition, about 20% of MTC terminals supporting MTC services such as smart metering are installed in a 'Deep indoor' environment such as a basement. Therefore, in order to successfully transmit MTC data, It should be improved by about 20dB compared with the coverage of the terminal. In addition, LTE MTC terminal coverage should be improved by more than 20dB if additional performance degradation due to specification changes is taken into consideration.

Various methods for robust transmission such as PSD boosting or low coding rate and time domain repetition are considered for each physical channel in order to improve the coverage while lowering the price of the LTE MTC terminal.

The requirements of low-cost MTC terminal based on LTE are as follows.

- The data transmission rate shall satisfy the data transmission rate provided by the minimum EGPRS based MTC terminal, that is 118.4kbps downlink and 59.2kbps uplink.

- Frequency efficiency should be improved dramatically compared to GSM / EGPRS MTC terminal.

- The service area provided shall not be less than that provided by the GSM / EGPRS MTC terminal.

- Power consumption should not be higher than GSM / EGPRS MTC terminal.

- Legacy LTE terminals and LTE MTC terminals should be available at the same frequency.

- Reuse existing LTE / SAE networks.

- Optimization is performed not only in FDD mode but also in TDD mode.

- Low-cost LTE MTC terminals should support limited mobility and low power consumption modules.

In order to allocate a Physical Downlink Shared Channel (PDSCH) transmitted from a base station to a mobile station or a Physical Uplink Shared Channel (PUSCH) transmission resource transmitted from a mobile station to a base station, the base station transmits the same subframe to which a PDSCH / PDCCH < / RTI > The PDCCH is a physical channel for transmitting downlink control information (DCI) including allocation information of a PDSCH / PUSCH transmission resource.

The PDCCH uses a control region consisting of a maximum of 4 OFDM symbols from the first OFDM symbol of a subframe. A control region is composed of a plurality of CCEs (Control Channel Elements), and one CCE is a basic unit that can be allocated as a transmission resource of a PDCCH. One CCE is composed of a plurality of resource element groups (REGs).

One DCI can be transmitted using 1, 2, 4 or 8 CCEs, and the number of CCEs used for one DCI transmission is referred to as CCE AL (Aggregation Level). At this time, the base station determines the AL based on the geometry of the terminal.

1 is a diagram illustrating an example of a PDCCH coding method.

Referring to FIG. 1, a base station generates a 16-bit CRC by performing cyclic redundancy check encoding on a DCI in order to transmit a DCI. Then, the base station masks the generated CRC to the RNTI and attaches the RNTI to the DCI (S100_). At this time, the RNTI used for CRC masking is a type of data or a logical channel logical channel), the values of Table 1 or Table 2 can be used.

<RNTI values> Value (hexa-decimal) RNTI 0000 N / A 0001-003C RA-RNTI, C-RNTI, Semi-Persistent Scheduling C-RNTI, Temporary C-RNTI, TPC-PUCCH-RNTI and TPC-
(see note) 003D-FFF3 C-RNTI, Semi-Persistent Scheduling C-RNTI, Temporary C-RNTI, TPC-PUCCH-RNTI and TPC-PUSCH-RNTI FFF4-FFFC Reserved for future use FFFD M-RNTI FFFE P-RNTI FFFF SI-RNTI

<RNTI usage> RNTI Usage Transport Channel Logical Channel P-RNTI Paging and System Information change notification PCH PCCH SI-RNTI Broadcast of System Information DL-SCH BCCH M-RNTI MCCH Information change notification N / A N / A RA-RNTI Random Access Response DL-SCH N / A Temporary C-RNTI Contention Resolution
(when no valid C-RNTI is available) DL-SCH CCCH Temporary C-RNTI Msg3 transmission UL-SCH CCCH, DCCH, DTCH C-RNTI Dynamically scheduled unicast transmission UL-SCH DCCH, DTCH C-RNTI Dynamically scheduled unicast transmission DL-SCH CCCH, DCCH, DTCH C-RNTI Triggering of PDCCH ordered random access N / A N / A Semi-Persistent Scheduling C-RNTI Semi-Persistently Scheduled unicast transmission
(activation, reactivation and retransmission) DL-SCH, UL-SCH DCCH, DTCH Semi-Persistent Scheduling C-RNTI Semi-Persistently Scheduled unicast transmission
(deactivation) N / A N / A TPC-PUCCH-RNTI Physical layer Uplink power control N / A N / A TPC-PUSCH-RNTI Physical layer Uplink power control N / A N / A

The base station encodes the DCI to which the CRC is attached using channel coding (S110). In step S120, the BS performs rate matching on the codeword configured with the channel coding encoding in consideration of the number of REs (Resource Elements) constituting the CCE of the AL and QPSK modulation.

On the other hand, the UE can not know which CCE is used by the base station among a plurality of CCEs constituting a control region of a subframe transmitted to the UE. Accordingly, the UE configures the PDCCH used by the BS in consideration of an arbitrary CCE position and an arbitrary AL, and blindly decodes the received value on an arbitrary PDCCH. If the UE performs channel decoding on the received value, de-masking the received value using the RNTI value, and then checks the CRC, it is determined to be a DCI allocated to the UE.

At this time, when each UE performs PDCCH blind decoding, it is practically impossible to find all available CCE combinations for each AL and blind decode all the CCEs constituting the above-mentioned control areas. In order to solve such a problem, conventionally, PDCCH blind decoding is performed only for a predefined CCE combination by defining CCEs to be used for PDCCH blind decoding for each terminal in advance for each AL. As described above, a combination of predefined CCEs for PDCCH blind decoding is called a PDCCH SS (Search Space).

PDCCH SS consists of M ^(L) PDCCH candidates as shown in Table 3 for ALL. PDCCH candidate index m = 0, 1, ..., M ^(L) -1, and one PDCCH candidate is composed of L CCEs corresponding to L consecutive CCE indexes.

PDCCH candidates are monitored by an UE. Search space

Number of PDCCH candidates
M ^(L) Type Aggregation level L Size CCEs ] UE-specific

One

6 6 2 12 6 4 8 2 8 16 2

Common

4 16 4 8 16 2

The PDCCH SS is divided into a CSS (Common SS) and a USS (UE-specific SS). The CSS is always composed of CCE index 0 to L * M ^(L) -1 regardless of the RNTI value of the UE. The DCI transmitted by the CSS contains resource allocation information for common control messages such as SIB, RAR, and paging messages.

USS is composed of L * M ^(L) CCEs at different positions in every subframe using Equation (1) according to the RNTI value of the UE and a subframe number or a slot number. do.

In Equation (1), N _{CCE, k} denotes the total number of CCEs in the control region of the subframe k. L represents the above-described Aggregation Level. i is defined as 0, ..., L-1, m '= m for CSS and m = 0, ..., M ^(L) -1. M ^(L) denotes the number of PDCCH candidates for monitoring in a given search space.

The DCI transmitted to the USS contains resource allocation information for UE-specific data or a UE-specific control message

The base station can transmit DCI (Downlink Control Information) using EPDCCH as another method of transmitting allocation information of PDSCH / PUSCH transmission resources to the UE. The EPDCCH uses some 2, 4, or 8 PRB pairs (PRB-pair) among the transmission resources of the conventional PDSCH and is called an EPDCCH-PRB-set. The allocation information for the PRB pair included in the EPDCC-PRB-set is transmitted to each terminal through higher layer signaling. A plurality of EPDCCH-PRB-sets may be used in the same subframe.

The EPDCCH-PRB-set is composed of a plurality of ECCEs (Enhanced Control Channel Elements), and is a basic unit that one ECCE can allocate as a transmission resource of the EPDCCH.

The EPDCCH also forms an SS composed of a plurality of ECCEs according to the AL, like the PDCCH, and the UE performs blind decoding on the SS. At this time, only the USS exists in the SS of the EPDCCH.

As described above, in the past, the UE was able to receive the DCI using the PDCCH transmitted in the entire system bandwidth. However, as in the case of the low-cost MTC terminal, the RF bandwidth that the UE can transmit / receive is 1.4MHz (Or limited to 6PRB-pair), it can no longer receive the PDCCH. Therefore, as shown in FIG. 2, the DCI must be received using the EPDCCH existing in the 6PRB. However, there is a problem that resource allocation information for a common control message such as SIB, RAR, and paging message, which is transmitted only on the conventional PDCCH, can not be received any more.

Conventionally, the UE can successfully perform blind decoding on the reception value of the PDCCH transmitted in one subframe. However, in the case of the coverage extended MTC terminal, blind decoding can be successfully performed even if L = 8 or 16, none.

Therefore, the base station must repetitively transmit the EPDCCH to a plurality of subframes as shown in FIG.

Referring to FIG. 3, a UE receives an EPDCCH repeatedly transmitted in a plurality of subframes, blind decoding can be successfully performed only when an EPDCCH repeatedly transmitted DCI is combined with an EPDCCH received value for decoding, and repeatedly transmitted PDSCH resource allocation information. The UE can also confirm the PDSCH by combining and decoding a plurality of subframes.

As described above, in the case of the MTC terminal, a limited system bandwidth is used and it is impossible to receive data transmitted using the PDCCH full band like a common control message by performing repetitive transmission. Therefore, in the present invention, a method of setting transmission resources so that the MTC terminal can receive downlink control information and downlink data including radio resource allocation information even in a limited bandwidth will be described according to an embodiment. Hereinafter, the common control message will be referred to as downlink data commonly applied to a plurality of terminals, and the UE-specific control message will be referred to as downlink data applied to a UE. The DCI including the resource allocation information for the common control message is described as first downlink control information, the DCI including the resource allocation information for the UE-specific message is described as the second downlink control information, do. However, the above-described terms may be used in combination if necessary. Meanwhile, the first downlink control information and the second downlink control information in the present specification are arbitrarily classified to facilitate understanding, and may mean conventional downlink control information. However, as described above, the downlink control information may be divided into the first time zone and the second time zone depending on whether the control message is commonly applied to a plurality of UEs or applied to a specific UE. That is, the first downlink control information and the second downlink control information are conceptual definitions including some downlink control information according to the type of conventional downlink control information. Therefore, it is not limited to the word.

How to allocate resources in the time domain

4 is a diagram for explaining a method of allocating radio resources by classifying time zones of downlink control information and downlink data according to the present invention.

In the present invention, a TDM (Time Domain Multiplexing) scheme in which a time domain is periodically transmitted according to a type of data to be transmitted by a base station may be applied.

4, a PDSCH for a downlink data (common control message, for example) transmitted in common to a plurality of UEs, and a transmission resource for transmitting an EPDCCH in which first downlink control information is transmitted, (PDSCH) for a UE-specific data or a UE-specific control message to be transmitted to a specific UE, and a time domain 410 for transmitting an EPDCCH in which second downlink control information is transmitted. Resources can be allocated. For example, in the first time domain 400, the first downlink control information including the common control message and the resource allocation information for the common control message may be transmitted. Also, in the second time zone 410, the second downlink control information including resource allocation information for the UE-specific control message and the UE-specific control message may be transmitted.

However, the present invention does not limit the transmission of the EPDCCH and the PDCCH in which the UE identification data and the second downlink control information transmitted to the individual terminal are transmitted in the first time domain 400. [

Meanwhile, among the first time zone 400 and the second time zone 410, the first time zone 400 may be periodically configured at a time when the BS and the UE have agreed to each other in advance. For example, the SFN (System Frame Number) at which the first time domain starts can be defined as SFN mod P == S. Here, P and S are the values that the BS and the UE have agreed with each other, P is a period of a frame in which the first time domain exists, and S is the first time region among the SFN value ranges 0 to 1023 This is the SFN value of the first frame. Also, the start point and the period of the first time domain can be extended on a subframe basis.

For example, for the coverage extended MTC terminal in the first time zone 400, the first downlink control information transmitted to the first time zone 400 includes information for checking the coverage extension level supported by the base station can do. As another example, the coverage extension level for repeated transmission of the first downlink control information may be determined by repeatedly transmitting the EPDCCH considering the coverage extension level that the subscriber station and the base station preliminarily promise (or the maximum coverage extension level) (For example, a common control message, a SIB, etc.) transmitted through the PDSCH transmission resource allocated to the base station.

Meanwhile, the data transmitted in the first time zone 400 may include various information.

For example, the first downlink control information transmitted in the first time domain 400 or the downlink data (e.g., SIB) commonly applied to a plurality of terminals may be the time (E.g., information on the size of the time domain) of the region. Or the time information of the first time zone 400 may be a value that the terminal and the base station have agreed to in advance. In this way, the size of the first time zone 400 is limited and the MTC terminal operates only at the corresponding time, thereby unnecessary power consumption can be prevented.

As another example, the first downlink control information transmitted to the first time domain 400 or the downlink data commonly applied to a plurality of terminals may include information on a starting point at which the second time domain 410 starts, Area 410 of the second area. In this manner, the size of the second time zone is limited and the MTC terminal operates only at the corresponding time, thereby unnecessary power consumption can be prevented.

5 is a diagram illustrating an example of downlink control information and downlink data transmitted in a first time domain according to the present invention.

Referring to FIG. 5, in the first time zone 400, a plurality of common control messages may be transmitted. For example, SIB and RAR may be transmitted, respectively. In addition, a DCI including information for allocating radio resources of the SIB and a DCI including information for allocating radio resources of the RAR can be respectively included. In addition, downlink data that can be commonly applied to a plurality of terminals, such as a paging message, may be transmitted in the first time zone 400. [

As described above, in the first time domain 400 and the second time domain 410 defined in the time axis, the MTC terminal performs blind decoding of the first downlink control information and the second downlink control information, respectively. If the blind decoding is successful, the MTC terminal obtains the resource allocation information of the PDSCH or the PUSCH from the corresponding downlink control information and receives the PDSCH or the PUSCH with the corresponding transmission resource.

Also, the second time zone 410 is also applied to the uplink transmission channel, so that the low-rate MTC terminal or the MTC terminal with the coverage extension can be restricted to perform the uplink transmission only during the time period of the second time zone.

Hereinafter, resource allocation in the frequency domain for the first time domain and the second time domain will be described.

How to allocate resources in the frequency domain

The MTC terminal can operate at a system bandwidth greater than 1.4 MHz even if the RF bandwidth that can be transmitted and received by the terminal is restricted to 1.4 MHz (or 6 PRB-pair).

Table 4 shows the number of PRB pairs available for each system bandwidth.

BW 1.4MHz 3MHz 5MHz 10MHz 15MHz 20MHz

6 15 25 50 75 100

The PRB-pair allocated to the conventional EPDCCH is configured considering the number of PRB-pairs corresponding to the total system bandwidth. More specifically, it is assumed that all possible combinations of the number of PRB-pairs to be used in the EPDCCH with respect to the number PRB-pair number information PRD-Pairs-r11 used in the EPDCCH and the number of PRB- And informs the UE of resourceBlockAssignment-r11, which is the index information selected by the base station for using the EPDCCH, by upper layer signaling.

However, in the case of the MTC terminal, since the maximum frequency resource that can be received per subframe is limited to 6 PRB-pairs, it is difficult to use the method of allocating frequency resources of the EPDCCH in the conventional method.

In order to solve such a problem, in the present invention, the range of the PRB index is defined as follows in the PRB-pair indication method which is conventionally used so that the frequency resource used for the EPDCCH can always be selected only within 6PRBs consecutively do.

Where x is 0 -6 value, and the x value represents the smallest PRB pair index among six PRB pair indexes that the MTC terminal can use.

Next, a method for determining the x value and the PRB index used in the EPDCCH will be described.

In the case of the first time domain 400, since the MTC terminal can not receive another higher layer signaling, the base station and the MTC terminal use the promised PRB index.

For example, x is Floor (

/ 2) -3 or Ceil (

/ 2) -3 can be used. Accordingly, the MTC terminal determines that the PRB index of the frequency resource used in the first time domain 400 is Floor (

/ 2) -3 to Floor (

/ 2) +2 6 PRB pair or Ceil (

/ 2) -3 to Ceil (

/ 2) + 2 PRB pair, the transmission resource of the predefined frequency domain can be used.

The number of PRB pair sets used in EPDCCH

(E.g., 2 or 4) predefined by the terminal and the base station.

In addition, a combinatorial index r value may be a predefined value (for example, 0) defined by the MTC terminal and the base station in order to construct a PRB pair set used as an EPDCCH from among the six PRB indexes described above.

The joint index uses a PRB-pair indication method for a conventional EPDCCH (see TS 36.213 9.1.4.4 PRB-pair indication for EPDCCH section). However, in the present invention,

Value is fixed to 6, which is the maximum number of PRBs that can be used by the MTC terminal. The BS determines the PRB index

The PRB pair index used for the EPDCCH transmission is added by adding the x value which is the smallest PRB pair index among the six PRB pair indexes available to the MTC terminal. Alternatively, regardless of the value of the coupling index r, the values of x to x +

A PRB-pair corresponding to the PRB index up to -1 may be used as the PRB pair set.

In the case of the second time zone 410, since the MTC UE can use the common control message received first in the first time zone 400, the common control message includes the second time zone 410, A minimum value x of six PRB indexes, a combination index r value corresponding to a PRB index to be used for an EPDCCH among six PRB pairs and a number of PRB pair sets used for an EPDCCH

May be included.

The above-mentioned x value may be a value generated by a function of SFN so that its value changes in the time domain, a value generated by a function of the subframe number, or a value generated by a function using both the SFN and the subframe number .

Alternatively, a function of the terminal's unique identification number (e.g., C-RNTI value) may be used to use the terminal specific x value. Alternatively, a function of a unique identification number (e.g., CellID or PCI value) of the base station may be used to use a cell specific x value.

The combinatorial index r value may be a value generated by a function of the SFN so that its value changes in the time domain, a value generated by a function of the subframe number, or a combination of the SFN and the subframe number It can be a value generated by a function. A function of the terminal's unique identification number (e.g., C-RNTI value) may be used to use the terminal specific r value. Alternatively, a function of a unique identification number (e.g., CellID or PCI value) of the base station may be used to use a cell specific r value.

As described above, if the RF bandwidth that can be transmitted and received by the terminal is limited to 1.4 MHz (or limited to 6 PRB-pairs), such as a low-cost MTC terminal, PDSCH for the PDSCH transmission resource of the common control message and DCI including the resource allocation information for the PDSCH transmission resource of the common control message.

Hereinafter, transmission resources of the MTC terminal set in the time domain and the frequency domain of the present invention will be described with reference to the operations of the MTC terminal and the base station.

6 is a diagram for explaining the operation of the MTC terminal according to an embodiment of the present invention.

A method of receiving downlink data according to an exemplary embodiment of the present invention includes receiving first downlink control information (Downlink Control Information) including resource allocation information of downlink data commonly applied to a plurality of terminals, DCI) in a first time domain and repeatedly receiving second downlink control information including resource allocation information of downlink data applied in a UE in a second time domain, Confirming downlink data commonly applied to a plurality of terminals based on the link control information, and identifying downlink data applied to the terminal based on the second downlink control information.

Referring to FIG. 6, the MTC terminal of the present invention repeats first downlink control information (DCI) including resource allocation information of downlink data commonly applied to a plurality of terminals in a first time domain (S600). As described with reference to FIGS. 1 to 5, the first downlink control information including downlink data and resource allocation information commonly applied to a plurality of terminals is divided into a first time domain It can be repeatedly received. For example, a DCI including a common control message and resource allocation information for a common control message may be received in a first time domain.

Also, downlink data or first downlink control information commonly applied to a plurality of terminals may include at least one of information on a first time domain, information on a starting point of a second time domain, and information on a time domain of a second time domain . For example, the downlink data or the first downlink control information received in the first time domain may include information on the size of the first time domain. Or the downlink data or the first downlink control information received in the first time domain includes at least one of the start point information of the second time domain and the size information of the second time domain which are configured after the first time domain .

Meanwhile, the first downlink control information is allocated to a frequency-axis radio resource determined based on a predetermined physical resource block (PRB) index value, a preset number of sets of physical resource block pairs, and a preset combination index value .

In addition, downlink data commonly applied to a plurality of UEs may include radio resource allocation information on a frequency-axis resource to which second downlink control information is allocated. For example, the downlink data or the first downlink control information received in the first time domain may be a physical resource block index value or a set of physical resource block pairs associated with a frequency domain resource to which the second downlink control information is allocated, A binding index value, and the like.

In step S602, the MTC terminal repeatedly receives second downlink control information including resource allocation information of downlink data to be applied to a UE in a second time domain. For example, the MTC terminal may receive the second downlink control information including the downlink data and the resource allocation information for the corresponding data in a second time domain different from the first time domain. The MTC terminal may receive the terminal specific data or the second downlink control information repeatedly in the second time domain by acquiring the starting point or the section information of the second time domain based on the information received in the first time domain.

Also, the MTC terminal confirms the downlink data commonly applied to the plurality of terminals based on the first downlink control information, and confirms the downlink data applied to the terminal based on the second downlink control information (S604). For example, the common control message may be identified in the first time domain, and the UE-specific control message may be identified in the second time domain. Also, the MTC terminal can confirm the first downlink control information based on a preset PRB index, the number of PRB pairs, a combined index value, and the like. Also, the MTC terminal can confirm the second downlink control information on the frequency axis based on the information received in the first time domain.

In addition, the MTC terminal of the present invention can perform all of the operations of the present invention described with reference to FIG. 1 to FIG.

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

A method of transmitting downlink data according to another exemplary embodiment of the present invention includes transmitting first downlink control information (DCI) including resource allocation information of downlink data commonly applied to a plurality of UEs, And allocating radio resources of second downlink control information including resource allocation information of downlink data to be applied to a UE, transmitting first downlink control information in a first time domain, And transmitting link control information in a second time domain.

Referring to FIG. 7, a BS includes first downlink control information (DCI) including resource allocation information of downlink data commonly applied to a plurality of UEs, and downlink control information And allocating radio resources of second downlink control information including allocation information (S700). For example, the base station may transmit the first downlink control information and the second downlink control information in a time domain. That is, downlink data commonly applied to a plurality of terminals, such as the first downlink control information and the common control message, may be allocated to the first time domain. In the second time domain, downlink data to be applied to a specific UE such as second downlink control information and a UE-specific control message may be allocated.

Meanwhile, the base station may allocate the first downlink control information and the second downlink control information by dividing them into frequency axes. The first downlink control information may be allocated on the frequency axis based on the MTC terminal and a preset PRB index value, the number of PRB pair sets, and a combined index value.

In addition, the base station includes transmitting the first downlink control information in a first time domain (S702). For example, the base station transmits the first downlink control information in the first time domain. Also, the base station may transmit downlink data scheduled by the first downlink control information in a first time domain. In one example, the downlink data may be a common control message. On the other hand, downlink data or first downlink control information commonly applied to a plurality of terminals includes at least one of period information of a first time period, starting point information of a second time period, and period information of a second time period . In addition, the downlink data commonly applied to a plurality of UEs may include radio resource allocation information on frequency-axis resources to which the second downlink control information is allocated.

In addition, the base station includes transmitting the second downlink control information in a second time domain (S704). The base station can transmit the second downlink control information according to the start point and the interval information of the second time domain included in the information of the first time domain. Also, the base station can transmit downlink data specific to the UE in the second time domain. Meanwhile, the base station may receive the PUSCH of the MTC terminal in the second time domain.

In addition, the base station of the present invention can perform all the base station operations required to perform each of the embodiments described with reference to FIG. 1 to FIG.

8 is a diagram illustrating a configuration of a user terminal according to another embodiment of the present invention.

Referring to FIG. 8, the MTC terminal 800 according to another embodiment of the present invention includes first downlink control information (DCI) including resource allocation information of downlink data commonly applied to a plurality of terminals A receiver 830 for repeatedly receiving the second downlink control information including the resource allocation information of downlink data applied to the UE in a first time domain in a second time domain, And a control unit 810 for identifying downlink data commonly applied to a plurality of terminals based on the control information and for identifying downlink data to be used for terminal identification based on the second downlink control information.

The receiver 830 receives downlink data commonly applied to a plurality of terminals in a first time domain, and receives downlink data applied to a terminal in a second domain. Also, downlink data or first downlink control information commonly applied to a plurality of terminals may include at least one of information on a first time domain, information on a starting point of a second time domain, and information on a time domain of a second time domain . Alternatively, downlink data commonly applied to a plurality of UEs may include radio resource allocation information on a frequency axis resource to which second downlink control information is allocated.

In addition, the receiver 830 receives downlink control information, data, and messages from the base station through the corresponding channel.

In addition, the control unit 810 controls the first downlink (UL) resource in a frequency-axis radio resource determined based on a predetermined physical resource block (PRB) index value, a preset number of physical resource block pair sets, The control information can be confirmed. In addition, the control unit 810 controls the overall MTC terminal 800 to identify the downlink data and the downlink control information transmitted by dividing the time interval according to the type of the downlink data required to perform the present invention, .

Meanwhile, the transmitter 820 transmits uplink control information, data, and a message to the base station through the corresponding channel. For example, the transmitter 820 may transmit the uplink data to the base station according to the second downlink control information in the second time domain.

9 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.

9, the base station 900 according to another exemplary embodiment may include first downlink control information (DCI) including resource allocation information of downlink data commonly applied to a plurality of terminals, A control unit 910 for allocating radio resources of second downlink control information including specific allocation of downlink data resource allocation information, and a control unit 910 for transmitting the first downlink control information in a first time domain, And a transmitter 920 for transmitting control information in a second time domain.

The transmitter 920 may transmit downlink data commonly applied to a plurality of terminals in a first time domain and may transmit downlink data applied to a terminal in a second domain. The downlink data or the first downlink control information, which is commonly applied to a plurality of terminals, includes at least one of period information of a first time period, starting point information of a second time period, and period information of a second time period . In addition, downlink data commonly applied to a plurality of UEs may include radio resource allocation information on a frequency-axis resource to which second downlink control information is allocated.

The control unit 910 assigns the first downlink control information to the frequency-axis radio resource determined based on a predetermined physical resource block (PRB) index value, a preset number of physical resource block pair sets, Can be assigned. In addition, the controller 910 can control the overall operation of the base station 900, which is necessary for distinguishing the time domain according to the downlink data type of the present invention and for dividing and transmitting frequency resources.

In addition, the transmitting unit 920 and the receiving unit 930 are used to transmit and receive signals, messages, and data necessary for performing the above-described present invention to and from 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

A method of receiving downlink data by a MTC (Machine Type Communication)
The method comprising: repeatedly receiving first downlink control information (DCI) including resource allocation information of downlink data commonly applied to a plurality of UEs in a first time domain;
Receiving second downlink control information including resource allocation information of downlink data applied to a UE repeatedly in a second time domain; And
Identifying downlink data commonly applied to the plurality of terminals based on the first downlink control information and identifying downlink data applied to the terminal based on the second downlink control information, Methods of inclusion.

The method according to claim 1,
Wherein downlink data commonly applied to the plurality of terminals is received in the first time domain,
Wherein the downlink data applied to the UE is received in the second region.

The method according to claim 1,
Wherein the downlink data or the first downlink control information, which is commonly applied to the plurality of terminals,
Wherein the information includes at least one of the first time domain information, the second time domain start information, and the second time domain information.

The method according to claim 1,
Wherein the first downlink control information comprises:
A predetermined physical resource block (PRB) index value, a predetermined number of physical resource block pair sets, and a predetermined combined index value.

The method according to claim 1,
The downlink data, which is commonly applied to the plurality of terminals,
And radio resource allocation information on a frequency-axis resource to which the second downlink control information is allocated.

A method for transmitting downlink data in a base station,
A first downlink control information (DCI) including resource allocation information of downlink data commonly applied to a plurality of terminals, and a second downlink control information including downlink control information Allocating radio resources of the link control information;
Transmitting the first downlink control information in a first time domain; And
And transmitting the second downlink control information in a second time domain.

The method according to claim 6,
Wherein downlink data commonly applied to the plurality of terminals is transmitted in the first time domain,
Wherein the downlink data applied to the UE is transmitted in the second region.

The method according to claim 6,
Wherein the downlink data or the first downlink control information, which is commonly applied to the plurality of terminals,
Wherein the information includes at least one of the first time domain information, the second time domain start information, and the second time domain information.

The method according to claim 6,
Wherein the first downlink control information comprises:
A predetermined physical resource block (PRB) index value, a predetermined number of physical resource block pair sets, and a predetermined combined index value.

The method according to claim 6,
The downlink data, which is commonly applied to the plurality of terminals,
And radio resource allocation information on a frequency-axis resource to which the second downlink control information is allocated.

1. An MTC (Machine Type Communication) terminal for receiving downlink data,
The method includes receiving first downlink control information (DCI) including resource allocation information of downlink data commonly applied to a plurality of UEs in a first time domain,
A receiver for repeatedly receiving second downlink control information including resource allocation information of downlink data applied in a terminal in a second time domain; And
A controller for checking downlink data commonly applied to the plurality of terminals based on the first downlink control information and for identifying downlink data applied to the terminal based on the second downlink control information, Included terminal.

12. The method of claim 11,
The receiver may further comprise:
Receiving downlink data commonly applied to the plurality of terminals in the first time domain,
And the downlink data to be applied to the terminal is received in the second region.

12. The method of claim 11,
Wherein the downlink data or the first downlink control information, which is commonly applied to the plurality of terminals,
Wherein the information includes at least one of the first time domain information, the second time domain information, and the second time domain information.

12. The method of claim 11,
Wherein the first downlink control information comprises:
Wherein the frequency resource allocation unit is allocated to a frequency-axis radio resource determined based on a preset physical resource block (PRB) index value, a preset number of physical resource block pair sets, and a preset combination index value.

12. The method of claim 11,
The downlink data, which is commonly applied to the plurality of terminals,
And radio resource allocation information on a frequency axis resource to which the second downlink control information is allocated.

A base station for transmitting downlink data,
A first downlink control information (DCI) including resource allocation information of downlink data commonly applied to a plurality of terminals, and a second downlink control information including downlink control information A control unit for allocating radio resources of the link control information; And
And a transmitter for transmitting the first downlink control information in a first time domain and transmitting the second downlink control information in a second time domain.

17. The method of claim 16,
The transmitter may further comprise:
Wherein downlink data commonly applied to the plurality of terminals is transmitted in the first time domain, and downlink data applied to the terminal is transmitted in the second domain.

17. The method of claim 16,
Wherein the downlink data or the first downlink control information, which is commonly applied to the plurality of terminals,
Wherein the information includes at least one of period information of the first time period, starting point information of the second time period, and period information of the second time period.

17. The method of claim 16,
Wherein the first downlink control information comprises:
Wherein the base station is allocated to a frequency-axis radio resource determined based on a preset physical resource block (PRB) index value, a preset number of sets of physical resource blocks, and a preset combination index value.

17. The method of claim 16,
The downlink data, which is commonly applied to the plurality of terminals,
Wherein the second downlink control information includes radio resource allocation information on a frequency-axis resource to which the second downlink control information is allocated.