WO2015053553A1

WO2015053553A1 - Method for transmitting and receiving random access response, and apparatus therefor

Info

Publication number: WO2015053553A1
Application number: PCT/KR2014/009471
Authority: WO
Inventors: 박규진; 최우진
Original assignee: 주식회사 케이티
Priority date: 2013-10-10
Filing date: 2014-10-08
Publication date: 2015-04-16

Abstract

As a method for allocating a PDSCH resource for transmitting an RAR message for an MTC terminal, the present invention provides a method for allocating a semi-static PDSCH resource for transmitting RAR, not a dynamic scheduling through a PDCCH, and an apparatus therefor. Further, the present invention provides a method for performing, by a base station, random access procedures, and an apparatus therefor, the method comprising the steps of: receiving a random access preamble; forming a random access response related to the random access preamble or forming a random access response EPDCCH set on the basis of the format of a random access response message; and transmitting the random access response.

Description

Random access response transmission and reception method and apparatus

The present invention relates to a method and apparatus for transmitting and receiving a random access response in a wireless communication system, and more particularly, when repeatedly transmitting and receiving a random access response to a terminal located in enhanced coverage compared to coverage for a general terminal, A method and apparatus for transmitting and receiving a random access response by determining a resource to which a response is assigned.

The present invention also relates to a method and apparatus for transmitting a random access response in a random access process of a terminal requiring enhanced coverage compared to coverage for a general terminal.

Machine type communication (hereinafter referred to as "MTC" communication) is a form of data communication, in which one or more entities represent machine or machine communication that does not necessarily require human interaction. . MTC communication that does not require human interaction refers to all communication methods in which communication is performed without human intervention in the communication process.

The MTC terminal may be installed in a place where the radio environment is worse than that of the general terminal. In order for an MTC terminal to operate in a place where a radio environment is worse than that of a general terminal, it may be necessary to repeatedly transmit control information and / or data of each physical channel transmitted in one subframe unit in a plurality of subframes.

Meanwhile, since a random access response (hereinafter referred to as "RAR") for a general terminal is not repeatedly transmitted in a plurality of subframes, a resource to which a random access response is allocated is repeatedly transmitted. Can be determined without consideration.

Meanwhile, the terminal may perform a random access procedure as an initial access procedure with the base station. In the random access procedure, a random access response message is repeatedly transmitted for the MTC terminal, and the MTC terminal also receives and combines the repeated random access response. However, this procedure has a problem of causing excessive overhead in the control area or data area.

The present invention provides a method and apparatus for transmitting and receiving a random access response by determining a resource to which a random access response is allocated when repeatedly transmitting a random access response for an MTC terminal in a plurality of subframes in order to overcome the aforementioned problem. The purpose.

Another object of the present invention is to provide a method and apparatus for reducing excessive load due to repetitive transmission even when transmitting a random access response for a coverage limited MTC terminal.

Another object of the present invention is to provide a method and apparatus for providing an appropriate amount of radio resources according to the size of a random access response even when a random access response is transmitted through a fixed PDSCH resource.

According to an embodiment of the present invention, a method for receiving a random access response by a terminal includes: a subframe in which the terminal transmits a random access preamble and a subframe in which the terminal receives a random access response related to the random access preamble. Receiving subframe information indicating a relationship; Transmitting a random access preamble; And receiving a random access response related to the random access preamble through a subframe determined based on the subframe information. The subframe information may also include information indicating a difference between a subframe in which the terminal transmits the random access preamble and a subframe in which the terminal receives the random access response. The subframe information may also include information indicating an index of a subframe in which the terminal receives the random access response. In addition, the subframe information provides a method comprising the information of the radio frame and the information of the subframe in which the terminal receives the random access response. The subframe information may include a plurality of candidate values, and in the step of receiving the random access response, the terminal attempts to receive the random access response using each candidate value. to provide. The random access preamble is repeatedly received through a plurality of subframes, and the number of the plurality of subframes is determined based on at least one of the number of repetitive transmissions of the random access preamble and the format of the random access preamble. It provides a method characterized by. In addition, the random access preamble is repeatedly received over a plurality of subframes, and further comprising the step of receiving information indicating the number of the plurality of subframes.

Another embodiment of the present invention provides a method for receiving a random access response by a terminal, the method comprising: determining a resource block to which a random access response is assigned; Transmitting a random access preamble; And receiving a random access response related to the random access preamble through the determined resource block. Also, in the determining of the resource block to which the random access response is allocated, the number of resource blocks and the location of the resource blocks are provided in advance. Also, in the determining of the resource blocks to which the random access response is allocated, the number of resource blocks is set in advance and the location of the resource blocks is at least one of a downlink bandwidth, an index of a subframe, and an index of a slot. It provides a method characterized in that it is determined based on. Also, in the determining of the resource block to which the random access response is allocated, the information on the resource block to which the random access response is allocated is provided.

Another embodiment of the present invention is a method of transmitting a random access response by a base station, and a relationship between a subframe in which the terminal transmits a random access preamble and a subframe in which the terminal receives a random access response related to the random access preamble. Transmitting subframe information indicating a; Receiving a random access preamble; And transmitting a random access response related to the random access preamble on a subframe determined based on the subframe information. The subframe information may also include information indicating a difference between a subframe in which the terminal transmits the random access preamble and a subframe in which the terminal receives the random access response. The subframe information may also include information indicating an index of a subframe in which the terminal receives the random access response. In addition, the subframe information provides a method comprising the information on the radio frame (radio frame) and the subframe information in which the terminal receives the random access response. In addition, the subframe information provides a method comprising a plurality of candidate values. The random access preamble is repeatedly transmitted through a plurality of subframes, and the method further includes transmitting information indicating the number of the plurality of subframes.

Another embodiment of the present invention provides a method for transmitting a random access response by a base station, comprising: transmitting information on a resource block to which a random access response is allocated to a terminal; Receiving a random access preamble; And transmitting a random access response related to the random access preamble through the resource block.

Another embodiment of the present invention provides a terminal for receiving a random access response, comprising: a transmitter for transmitting a random access preamble; And a receiver configured to receive a random access response related to the random access preamble through a subframe determined based on the subframe information, wherein the receiver includes the random access preamble before the terminal transmits the random access preamble. The terminal provides subframe information indicating a relationship between a subframe transmitting the subframe and the subframe receiving the random access response related to the random access preamble. The subframe information may include information indicating a difference between a subframe in which the terminal transmits the random access preamble and a subframe in which the terminal receives the random access response. The subframe information may include information indicating an index of a subframe in which the terminal receives the random access response. In addition, the subframe information provides a terminal characterized in that the terminal includes the information of the radio frame (radio frame) and the subframe to receive the random access response. The subframe information includes a plurality of candidate values, and the receiver provides a terminal that attempts to receive the random access response using each candidate value. The random access preamble is repeatedly received through a plurality of subframes, and the number of the plurality of subframes is determined based on at least one of the number of repetitive transmissions of the random access preamble and the format of the random access preamble. It provides a terminal characterized by. The random access preamble is repeatedly received through a plurality of subframes, and the receiver provides a terminal for receiving information indicating the number of the plurality of subframes.

Another embodiment of the present invention provides a terminal for receiving a random access response, comprising: a control unit for determining a resource block to which a random access response is allocated; A transmitter for transmitting a random access preamble; And a receiver configured to receive a random access response related to the random access preamble through the determined resource block. In addition, the number of resource blocks is set in advance and the location of the resource block is provided based on at least one of the downlink bandwidth, the index of the subframe, and the index of the slot provides a terminal. In addition, the information on the resource block to which the random access response is allocated provides a terminal, characterized in that received from the base station through the receiving unit.

Another embodiment of the present invention provides a base station for transmitting a random access response, comprising: a receiving unit for receiving a random access preamble; And a transmitter configured to transmit a random access response related to the random access preamble, wherein the transmitter includes a subframe in which the terminal transmits the random access preamble and the terminal access the random access before receiving the random access preamble. Provided is a base station characterized by transmitting subframe information indicating a relationship between subframes receiving a random access response related to a preamble. The subframe information provides a base station including information indicating a difference between a subframe in which the terminal transmits the random access preamble and a subframe in which the terminal receives the random access response. In addition, the subframe information provides a base station characterized in that it includes information indicating the index of the subframe in which the terminal receives the random access response. In addition, the subframe information provides a base station characterized in that the terminal includes the information of the radio frame (radio frame) and the subframe to receive the random access response. In addition, the subframe information provides a base station comprising a plurality of candidate values. The random access preamble is repeatedly transmitted through a plurality of subframes, and the transmitter provides a base station further transmitting information indicating the number of the plurality of subframes.

Another embodiment of the present invention provides a base station for transmitting a random access response, comprising: a receiving unit for receiving a random access preamble; And a transmitter for transmitting a random access response related to the random access preamble, wherein the transmitter transmits information about a resource block to which the random access response is allocated to the terminal before receiving the random access preamble. Provided is a base station.

Meanwhile, another embodiment of the present invention provides a method for performing a random access procedure by a base station, and includes configuring a random access response related to the random access preamble based on a step of receiving a random access preamble and a format of a random access response message. It provides a method comprising constructing a random access response EPDCCH set and transmitting a random access response. Also, when the random access response is configured based on the random access response message format, the random access response is transmitted through a search space set for each random access response message format. In addition, the PRB or VRB of the search space set for each random access response message format includes the total number of PRBs constituting the downlink system bandwidth, the slot number, the number of PRBs of the corresponding random access response message format, and the RA-RNTI. Provides a method that is determined by a function. Further, when the random access response is configured based on the random access response message format, the RA-RNTI value of the random access response is determined by one or more of the number of repetitions of the random access preamble and the random access response message format. It provides a way to be. In addition, when configuring the random access response EPDCCH set, the random access response provides a method to be transmitted through the random access response EPDCCH set. The method may further include transmitting the random access response EPDCCH set configuration information when configuring the random access response EPDCCH set. Also, the random access response EPDCCH set configuration information provides a method for transmitting through cell-specific higher layer signaling.

According to another embodiment of the present invention, in a method of performing a random access procedure by a terminal, transmitting a random access preamble and monitoring one or more search spaces set for each random access response message format or configuring a random access response EPDCH set Monitoring a random access response EPDCCH set based on the information; and receiving a random access response related to the random access preamble according to the monitoring result. In addition, the PRB or VRB of the search space set for each random access response message format includes the total number of PRBs constituting the downlink system bandwidth, the slot number, the number of PRBs of the corresponding random access response message format, and the RA-RNTI. Provides a method that is determined by a function. In addition, the RA-RNTI value of the random access response provides a method that is determined by one or more of the number of repetitions of the random access preamble and the random access response message format. In addition, the random access response EPDCCH set configuration information provides a method that is received through cell-specific higher layer signaling. In addition, the monitored random access response EPDCCH set provides a method for distinguishing and setting the random access response EPDCCH format.

According to another embodiment of the present invention, in a base station performing a random access procedure, a random access response related to a random access preamble or a random access response EPDCCH is configured based on a format of a random access response message and a receiver for receiving a random access preamble. Provided is a base station apparatus including a control unit constituting a set and a transmitter for transmitting a random access response. In addition, when the random access response is configured based on the random access response message format, the transmitter provides a base station apparatus for transmitting the random access response through a search space set for each random access response message format. In addition, the PRB or VRB of the search space set for each random access response message format includes the total number of PRBs constituting the downlink system bandwidth, the slot number, the number of PRBs of the corresponding random access response message format, and the RA-RNTI. Provided is a base station apparatus determined by a function. Further, when the random access response is configured based on the random access response message format, the RA-RNTI value of the random access response is determined by one or more of the number of repetitions of the random access preamble and the random access response message format. It provides a base station apparatus. In addition, when configuring the random access response EPDCCH set, the transmitter provides a base station apparatus for transmitting the random access response through the random access response EPDCCH set. In addition, when configuring the random access response EPDCCH set, the transmitter provides a base station apparatus for further transmitting the random access response EPDCCH set configuration information. In addition, the random access response EPDCCH set configuration information provides a base station apparatus for transmitting through cell-specific higher layer signaling.

According to another embodiment of the present invention, in a terminal performing a random access procedure, a transmitter for transmitting a random access preamble and one or more search spaces set for each random access response message format may be monitored or random access response EPDCH set configuration information may be used. It provides a terminal device including a control unit for monitoring a random access response EPDCCH set based on the base station and a receiving unit for receiving a random access response related to the random access preamble according to the monitoring result. In addition, the PRB or VRB of the search space set for each random access response message format includes the total number of PRBs constituting the downlink system bandwidth, the slot number, the number of PRBs in each random access response message format, and the RA-RNTI. Provides a terminal device determined by a function. In addition, the RA-RNTI value of the random access response provides a terminal device that is determined by one or more of the number of repetitions of the random access preamble and the random access response message format. The receiver further provides a terminal device for receiving the random access response EPDCCH set configuration information through cell specific higher layer signaling. In addition, the monitored random access response EPDCCH set provides a terminal device that is set separately for each random access response EPDCCH format.

According to the present invention described above, a method for determining a resource to which a random access response is allocated when repeatedly transmitting a random access response for an MTC terminal in a plurality of subframes can be provided.

In addition, the present invention provides an effect of reducing excessive load due to repetitive transmission even when transmitting a random access response for the coverage limited MTC terminal.

In addition, the present invention provides an effect of providing an appropriate amount of radio resources according to the size of the random access response even when transmitting a random access response through a fixed PDSCH resource.

1 is a diagram illustrating an initial cell access procedure of a terminal.

FIG. 2 is a diagram illustrating a random access procedure in FIG. 1.

3 is a diagram illustrating a process of transmitting a random access preamble and a random access response in the case of a general terminal.

4 is a diagram illustrating a process in which a random access preamble and a random access response are repeatedly transmitted in the case of an MTC terminal.

5 is a flowchart illustrating a method of setting a RAR transmission subframe according to an embodiment.

FIG. 6 is a diagram illustrating an example in which a start subframe of a RAR transmission subframe is set in an FDD system.

FIG. 7 is a diagram illustrating an example in which a start subframe of a RAR transmission subframe is set in a TDD system.

8 is a diagram illustrating another example in which a start subframe of a RAR transmission subframe is set in a TDD system.

9 is a diagram illustrating an example in which a starting subframe of an RAR transmission subframe is selected from a plurality of candidates.

10 is a flowchart illustrating a method of setting RAR transmission resources according to an embodiment.

11 is a diagram illustrating an example of a resource block allocated for RAR transmission.

12 is a diagram illustrating another example of a resource block allocated for RAR transmission.

13 is a flowchart illustrating a method of setting RAR transmission resources according to another embodiment.

14 is a block diagram illustrating a configuration of a terminal according to an embodiment of the present invention.

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

16 is a diagram exemplarily illustrating a repetitive transmission / reception operation of a random access preamble and a random access response of a coverage-expanded MTC terminal of the present invention.

17 is a signal diagram illustrating the operation of a terminal and a base station according to an embodiment of the present invention.

18 is a flowchart illustrating the operation of a base station according to another embodiment of the present invention.

19 is a diagram illustrating a random access response message format of the present invention.

20 is a flowchart illustrating the operation of a terminal according to another embodiment of the present invention.

21 is a signal diagram illustrating the operation of a terminal and a base station according to another embodiment of the present invention.

22 is a flowchart illustrating the operation of a base station according to another embodiment of the present invention.

23 is a flowchart illustrating the operation of a base station according to another embodiment of the present invention.

24 is a diagram illustrating an example of information elements that may be included in EPDCCH configuration information.

25 is a flowchart illustrating the operation of a terminal according to another embodiment of the present invention.

FIG. 26 exemplarily shows the number of EREGs per ECCE.

27 exemplarily shows an EPDCCH format.

28 is a block diagram showing a configuration of a base station according to another embodiment of the present invention.

29 is a block diagram illustrating a configuration of a terminal according to another embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

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

In other words, in the present specification, the MTC terminal may mean a newly defined 3GPP Release-13 low cost (or low complexity) UE category / type for performing LTE-based MTC related operations. Alternatively, in the present specification, the MTC terminal supports enhanced coverage compared to the existing LTE coverage, or supports UE category / type defined in the existing 3GPP Release-12 or lower, or newly defined Release-13 low cost (or lower power consumption). low complexity) can mean 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. The wireless communication system includes a user equipment (UE) and a base station (base station, BS, or eNB). In the present specification, a user terminal is a generic concept meaning a terminal in wireless communication. In addition, user equipment (UE) in WCDMA, LTE, and HSPA, as well as mobile station (MS) in GSM, user terminal (UT), and SS It should be interpreted as a concept that includes a 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, an Sector, a Site, and a BTS. Other terms such as a base transceiver system, an access point, a relay node, a remote radio head (RRH), a radio unit (RU), and a small cell may be called.

That is, in the present specification, a base station or cell covers some areas or functions covered by a base station controller (BSC) in CDMA, a Node-B in WCDMA, an eNB or a sector (site) in LTE / LTE-Advanced, and the like. It should be interpreted as a comprehensive meaning, and it is meant to cover all the 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 have a base station for controlling each cell, the base station may be interpreted in two senses. i) the device providing the megacell, the macrocell, the microcell, the picocell, the femtocell, the small cell in relation to the wireless area, or ii) the wireless area itself. In i) all devices which provide a given wireless area are controlled by the same entity or interact with each other to cooperatively configure the wireless area to direct the base station. The eNB, RRH, antenna, RU, LPN, point, transmit / receive point, transmit point, receive point, and the like, according to the configuration of the radio region, become an embodiment of the base station. In ii), the base station may indicate the radio area itself to receive or transmit a signal from a viewpoint of a user terminal or a neighboring base station.

Therefore, megacells, macrocells, microcells, picocells, femtocells, small cells, RRHs, antennas, RUs, low power nodes (LPNs), points, eNBs, transmit / receive points, transmit points, and receive points are collectively referred to as base stations. do.

In the present specification, the user terminal and the base station are two transmitting and receiving entities used to implement the technology or technical idea described in this specification in a comprehensive sense and are not limited by the terms or words specifically referred to. The user terminal and the base station are two types of uplink or downlink transmitting / receiving subjects used to implement the technology or the technical idea described in the present invention, and are used in a generic sense and are not limited by the terms or words specifically referred to. Here, the uplink (Uplink, UL, or uplink) refers to a method for transmitting and receiving data to the base station by the user terminal, the downlink (Downlink, DL, or downlink) means to transmit and receive data to the user terminal by the base station It means the way.

There is no limitation on the multiple access scheme applied to the wireless communication system. Various multiple access techniques 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-TDMA, OFDM-CDMA Can be used. One embodiment of the present invention can be applied to resource allocation in the fields of asynchronous wireless communication evolving to LTE and LTE-Advanced through GSM, WCDMA, HSPA, and synchronous wireless communication evolving to CDMA, CDMA-2000 and UMB. The present invention should not be construed as being limited or limited to a specific wireless communication field, but should be construed as including all technical fields to which the spirit of the present invention can be applied.

The uplink transmission and the downlink transmission may use a time division duplex (TDD) scheme that is transmitted using different times, or may use a frequency division duplex (FDD) scheme that is transmitted using different frequencies.

In addition, in a system such as LTE / LTE-Advanced, a standard is configured by configuring uplink and downlink based on one carrier or a pair of carriers. The uplink and the downlink include a Physical Downlink Control CHannel (PDCCH), a Physical Control Format Indicator CHannel (PCFICH), a Physical Hybrid ARQ Indicator CHannel (PHICH), a Physical Uplink Control CHannel (PUCCH), an Enhanced Physical Downlink Control CHannel (EPDCCH), and the like. Control information is transmitted through the same control channel, and data is configured by a data channel such as a physical downlink shared channel (PDSCH) and a physical uplink shared channel (PUSCH).

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

In the present specification, a cell means a component carrier having a coverage of a signal transmitted from a transmission / reception point or a signal transmitted from a transmission point or a transmission / reception point, and the transmission / reception point itself. Can be.

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

The multiple transmit / receive point is at least one having a base station or a macro cell (hereinafter referred to as an eNB) and a high transmission power or a low transmission power in a macro cell region, which is wired controlled by an optical cable or an optical fiber to the eNB. May be RRH.

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

Hereinafter, a situation in which a signal is transmitted and received through a channel such as a PUCCH, a PUSCH, a PDCCH, an EPDCCH, and a PDSCH may be expressed in the form of 'sending and receiving a PUCCH, a PUSCH, a PDCCH, an EPDCCH, and a PDSCH.'

In addition, hereinafter, a description of transmitting or receiving a PDCCH or transmitting or receiving a signal through the PDCCH may be used as a meaning including transmitting or receiving an EPDCCH or transmitting or receiving a signal through the EPDCCH.

That is, the physical downlink control channel described below may mean PDCCH or EPDCCH, and may also be used to include both PDCCH and EPDCCH.

In addition, for convenience of description, the EPDCCH, which is an embodiment of the present invention, may be applied to the portion described as the PDCCH, and the EPDCCH may be applied to the portion described as the EPDCCH as an embodiment of the present invention.

Meanwhile, high layer signaling described below includes RRC signaling for transmitting RRC information including an RRC parameter.

The eNB performs downlink transmission to the terminals. The eNB includes downlink control information and an uplink data channel (eg, a physical downlink shared channel (PDSCH), which is a primary physical channel for unicast transmission, and scheduling required to receive the PDSCH. For example, a physical downlink control channel (PDCCH) for transmitting scheduling grant information for transmission on a physical uplink shared channel (PUSCH) may be transmitted. Hereinafter, the transmission and reception of signals through each channel will be described in the form of transmission and reception of the corresponding channel.

1 is a diagram illustrating an initial cell access procedure of a terminal.

Referring to FIG. 1, in an initial cell access process of a terminal, the terminal 10 receives a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), which are synchronization signals transmitted from the base station 20 (S102). In the LTE Frequency Division Duplex (FDD), the PSS may be transmitted in the last symbol (#n) of the first slot of subframe # 0 and subframe # 5 in one radio frame (eg, 10 ms), The SSS may be transmitted in the previous symbol (# n-1) of the last symbol (#n) of the first slot of # 0 and subframe # 5. In LTE TDD, PSS / SSS may be transmitted to a location different from FDD. When the terminal 10 detects the PSS and the SSS, the terminal 10 may acquire cell ID and downlink synchronization information, and a cell-specific reference signal (CRS) based on the information obtained based on the PSS / SSS. ) Can perform additional synchronization and existing control channel decoding.

The terminal 10 receives a signal from the base station 20 through the PBCH based on the CRS (S104), and extracts a MIB (Master Information Block) transmitted through the PBCH (S106). The MIB may include information indicating a cell bandwidth, information indicating a PHICH configuration, and information indicating a system frame number. The terminal 10 can know the resource to which the PDCCH is allocated based on the information included in the MIB.

The terminal 10 receives a signal from the base station 20 through the PDCCH based on the CRS (S108), and extracts downlink control information (DCI) transmitted through the PDCCH (S110). DCI may be control information for a PDSCH through which a System Information Block (SIB) is transmitted, and may be delivered through a common search space.

The terminal 10 receives a signal from the base station through the PDSCH based on the DM-RS (Demodulation Reference) based on the DCI (S112), and extracts the SIB transmitted through the PDSCH (S114).

Thereafter, the terminal 10 and the base station 20 perform a random access procedure (S116), and the terminal 10 may be in an RRC connected state in an RRC idle state. .

FIG. 2 illustrates an operation S116 for performing the random access procedure of FIG. 1 in more detail.

According to a random access procedure defined in a conventional LTE or LTE-Advanced system, a random access response for random access preamble transmission of an arbitrary LTE or LTE-Advanced terminal A dynamic scheduling method may be applied to RAR) message transmission.

Referring to FIG. 2, the base station 20 transmits PRACH configuration information to the terminal 10 (S202). PRACH configuration information may be included in SIB2. The PRACH configuration information may include parameters preambleInitialReceivedTargetPower and powerRampingStep used when determining the transmit power of the PRACH. Detailed description of the parameters preambleInitialReceivedTargetPower and powerRampingStep will be described later.

The terminal 10 determines the transmission power of the PRACH and transmits a random access preamble to the base station 20 through the PRACH (S204). The random access preamble may inform the base station 20 that there is a random access attempt, and perform the function of allowing the base station 20 to estimate a delay between the terminal 10 and the base station 20. The random access preamble may be transmitted on the PRACH.

Upon receiving the random access preamble, the base station 20 transmits scheduling information on a random access response (RAR) to the terminal 10 through the PDCCH or the EPDCCH (S206). In this case, the random access response may be scheduled on a downlink shared channel (DL-SCH) designated by PDCCH or EPDCCH. Downlink control information (DCI) including scheduling information about the RAR may be scrambled to the RA-RNTI and transmitted through a PDCCH or an EPDCCH common search space (CSS).

The base station 20 transmits the RAR to the terminal 10 through the PDSCH, and the terminal 10 receiving the scheduling information for the RAR receives the RAR by using the same (S208).

Hereinafter, meaning that the random access response information transmitted by the base station is transmitted, the random access response message transmission and the random access response transmission may be used in the same meaning.

In more detail, the random access procedure will be described below.

The random access response to the random access preamble transmission of the terminal is transmitted through the downlink data channel, that is, the PDSCH. For example, the scheduling information for the corresponding random access response is configured in DCI format 1A or DCI format 1C, and is scrambled by a cyclic redundancy check (CRC) by a random access RNTI (RA-RNTI) to control a region. The PDCCH is transmitted through the Common Search Space (CSS). That is, in order to receive the random access response, which is a response message for the random access preamble transmission, the terminal must first decode the PDCCH including scheduling information about the random access response in CSS. In addition, at any base station, after receiving the random access preamble, it is possible to freely schedule the random access response within a certain time window.

Referring to FIG. 3, the terminal 10 transmits a random access preamble on a PRACH in uplink subframe #n. Upon receiving the random access preamble, the base station 20 transmits the RAR through the PDSCH in downlink subframe # (n + k). In this case, the UE 10 transmits a random access preamble in one uplink subframe (subframe #n), and the base station 20 performs RAR in one downlink subframe (subframe # (n + k)). Send it. When the UE 10 fails to transmit the random access preamble (or when the UE 10 fails to receive the RAR), the UE 10 transmits the random access preamble through the PRACH in the next PRACH transmission subframe.

[LTE-based low-cost MTC]

As LTE networks proliferate, mobile operators want to minimize the number of Radio Access Terminals (RATs) to reduce network maintenance costs. However, MTC products based on conventional GSM / GPRS networks are increasing, and MTCs using low data rates can be provided at low cost. Therefore, since the mobile operators use the LTE network for general data transmission and the GSM / GPRS network for the MTC, there is a problem of operating two RATs, which are inefficient use of the frequency band. It becomes burden on profit.

In order to solve this problem, cheap MTC terminal using GSM / EGPRS network should be replaced with MTC terminal using LTE network. To this end, various requirements for lowering the price of LTE MTC terminal are required for the 3GPP RAN WG1 standard meeting. Is discussed. In addition, the standard meeting is preparing a document describing various functions that can be provided to satisfy the requirements.

In order to support the low-cost LTE MTC terminal, the main items related to the physical layer specification change currently being discussed in 3GPP may include technologies such as narrowband support / single RF chain / half duplex FDD / Long DRX (Discontinued Reception). However, the above methods, which are considered to lower the price, may reduce the performance of the MTC terminal compared to the conventional LTE terminal.

In addition, since about 20% of MTC terminals supporting MTC services such as smart metering are installed in a 'deep indoor' environment such as a basement, for successful MTC data transmission, the coverage of the LTE MTC terminal is conventional LTE terminal. It should be improved by about 20dB compared to the coverage of. In addition, if the performance reduction due to the specification change is further considered, the coverage of the LTE MTC terminal should be improved by 20 dB or more.

In order to improve coverage while lowering the LTE MTC terminal price, a robust boost such as power spectral density (PSD) boosting or low coding rate and time domain repetition is performed. Various methods for transmission are considered for each physical channel.

The requirements of the LTE-based low-cost MTC terminal is as follows.

-The data transmission rate must satisfy the data transmission rate provided by the MGP terminal based on the enhanced GPRS (EGPRS) minimum, that is, downlink 118.4kbps, uplink 59.2kbps.

-Frequency efficiency must be significantly improved compared to GSM / EGPRS MTC terminal.

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

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

General LTE terminal and LTE MTC terminal should be available in the same frequency.

Reuse existing LTE / SAE networks.

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

Low-cost LTE MTC terminal must support limited mobility and low power consumption module.

In the present invention, a low-cost MTC terminal requiring coverage improvement due to poor radio channel transmission / reception performance compared to a general LTE / LTE-Advanced terminal will be referred to as a coverage limited MTC terminal.

To support extended coverage for coverage limited MTC terminal, the base station repeatedly transmits PDCCH or EPDCCH and PDSCH transmissions made in one downlink subframe unit through a plurality of downlink subframes, and the corresponding MTC terminal also It is necessary to perform decoding by combining PDCCH or EPDCCH and PDSCH received through the plurality of downlink subframes.

Accordingly, not only a random access response for an MTC terminal performing a random access procedure, but also a PDCCH including scheduling information about the random access response is repetitively transmitted through a plurality of downlink subframes. This may cause excessive overhead on PDCCH CSS.

The present invention proposes a PDSCH resource allocation scheme for RAR message transmission for MTC terminal. In particular, it proposes a semi-static PDSCH resource allocation scheme for RAR transmission, rather than dynamic scheduling via PDCCH.

The present invention proposes a PDSCH resource allocation scheme for RAR transmission for an MTC terminal. Specifically, a method for allocating a RAR transmission downlink subframe, a method for determining the number of RAR repetitions according thereto, and a method for allocating a PRB (Physical Resource Block) for RAR transmission in each downlink subframe will be proposed.

In order to improve the random access preamble reception performance of the coverage limited MTC terminal in an arbitrary LTE / LTE-Advanced base station, a new random access preamble format for the MTC terminal is newly defined or an existing random access preamble format is repetitively transmitted. May be considered.

For example, in case of a coverage limited MTC terminal, M uplink subframes (UL) are repeated by repeating M preambles generated based on a random access preamble format for an existing general LTE / LTE-A terminal as shown in FIG. 4 times. A scheme of transmitting in subframe # (n-M + 1) to UL subframe #n may be considered. In this case, the base station may repeat the RAR to the coverage limited MTC terminal L times and transmit in L downlink subframes (DL subframe # (n + k) to DL subframe # (n + k + L-1)). .

For another example, for a coverage limited MTC terminal, the length of a preamble format defined over M uplink subframes, that is, the sum of the CP length and the sequence length of the preamble format, that is, the value of T _CP + T _SEQ , or A method of transmitting a preamble generated based on a new random access preamble format having increased sequence length, length of T _SEQ ) may be considered.

In addition, the application of the semi-static scheduling method, rather than the existing dynamic scheduling method, for the allocation of the RAR message transmission resource for the corresponding coverage limited MTC terminal is considered.

As described above, in order to apply semi-static scheduling to a corresponding RAR, a definition of one or more downlink subframes in which the corresponding RAR is transmitted and a method of allocating PRBs for RAR transmission in the corresponding downlink subframe are required.

The present invention proposes a method for allocating a DL subframe allocation method for RAR, a method for determining the number of RAR repetitions associated therewith, and a method for allocating resource blocks (Resource Block (s)) in the corresponding DL subframe.

[Starting DL Subframes and Number of Iterations for RAR]

Referring to FIG. 5, the base station 20 transmits subframe information indicating a relationship between a subframe in which a random access preamble is transmitted and a subframe in which a random access response is transmitted, to the terminal 10 (S510). The terminal 10 transmits a random access preamble to the base station 20 (S520), and receives a random access response to the random access preamble through a downlink subframe determined based on the subframe information from the base station 20 ( S530).

In one example, the subframe information may be information indicating a subframe difference of a downlink subframe in which transmission of a random access response is started from an uplink subframe in which transmission of the random access preamble is terminated. That is, when transmission of the random access preamble is terminated in uplink subframe #n, transmission of a random access response may be started in downlink subframe # (n + k), and the subframe information is k May contain a value. The corresponding k value may be defined as any positive integer.

For example, the value of k may be 4 for an FDD system. FIG. 6 is a diagram illustrating an example in which a start subframe of a RAR transmission subframe is set in an FDD system. Referring to FIG. 6, a random access response is generated in a downlink subframe (subframe # (n + 4)) four subframes after the uplink subframe (subframe #n) where transmission of the repeated random access preamble is terminated. The transmission can be started.

For another example, in the case of a TDD system, the value of k may be a value set based on a UL-DL configuration and a subframe number of an uplink subframe in which transmission of a repeated random access preamble is terminated. FIG. 7 is a diagram illustrating an example in which a start subframe of a RAR transmission subframe is set in a TDD system. In the example of FIG. 7, the UL-DL configuration is 1 and the subframe number of the uplink subframe where transmission of the repeated random access preamble is terminated is 3. In this case, in this case, the value of k may be determined to be 6, and the transmission of the repeated random access response may begin from subframe 9.

In step S510, subframe information including information indicating a value of k may be transferred from the base station 20 to the terminal 10 through higher layer signaling (for example, RRC). Alternatively, the value of k may be a value previously set between the base station 20 and the terminal 10.

Meanwhile, the subframe information may be information indicating an index of the start subframe of the RAR transmission subframe. In the TDD system, the index #p of the starting subframe of the RAR transmission subframe is based on the UL frame subframe number #n of the uplink subframe where the transmission of the repeated random access preamble is terminated. Can be determined. 8 is a diagram illustrating another example in which a start subframe of a RAR transmission subframe is set in a TDD system. In the example of FIG. 8, when the transmission of the repeated random access preamble is an uplink subframe (subframe #n), the index of the downlink subframe at which transmission of the random access response is started may be determined to be #p. . In this case, when the radio frame at which the transmission of the repeated random access preamble is terminated is #M, the radio frame at which the transmission of the repeated random access response is started may be # (M + 1), which is the next radio frame. That is, when transmission of the repeated random access preamble ends in radio frame #M and subframe #n, transmission of the repeated random access response may start in radio frame # (M + 1) and subframe #p. In this case, the value of #p may be set to the same value regardless of the UL-DL configuration or to a different value for each UL-DL configuration. On the other hand, the transmission of the repeated random access response may begin in radio frame # (M + N), where N is a positive integer. Although the present embodiment has been described above with reference to the TDD system, it is also possible to apply the FDD system.

In step S510, subframe information including information indicating a value of p and / or a value of N may be transferred from the base station 20 to the terminal 10 through higher layer signaling (eg, RRC). Alternatively, the value of p and / or the value of N may be a value previously set between the base station 20 and the terminal 10.

Meanwhile, the above-described k value or p value may not have a single value but may have a plurality of values within a predetermined range.

For example, the value of k may have any positive integer value that satisfies k1 ≦ k ≦ k2. When the terminal 10 terminates the transmission of the random access preamble repeated in the uplink subframe #n, the terminal 10 is within the downlink subframe # (n + k1) to subframe # (n + k2) It can be expected that RAR transmission starts from one of the subframes included. That is, in case of FDD, the UE 10 can expect to start RAR transmission from one of k2-k1 + 1 subframes, and in case of TDD, from one of k2-k1 + 1 or less subframes. You can expect the RAR transmission to begin. The terminal 10 may perform RAR detection for each candidate of each RAR transmission start subframe.

9 is a diagram illustrating an example in which a starting subframe of an RAR transmission subframe is selected from a plurality of candidates. In the example of FIG. 9, k has a range of 4 ≦ k ≦ 6. UE 10 attempts to detect RAR in L subframes from subframe # (n + 4), attempts to detect RAR in L subframes from subframe # (n + 5), and subframe # (n From +6), RAR detection can be attempted in L subframes.

In the above-described embodiments, the terminal 10 receives subframe information including information indicating k, p, and / or N from the base station 20 through higher layer signaling, so that the RAR transmission subframe is quasi- It is described to be statically scheduled. However, in other embodiments, k, p, and / or N may have values previously promised at terminal 10 and base station 20.

Meanwhile, the L value, which is the number of times the random access response is repeated, may be defined as a function of the M value or the random access preamble format, the number of repetitions of the random access preamble format. For example, the L value, which is the number of times the random access response is repeated, may be set to be proportional to the M value, which is the number of repetitions of the random access preamble format. For another example, the L value, which is the number of times the random access response is repeated, may be set to be proportional to the length of the random access preamble format (that is, the value of T _CP + T _SEQ of the preamble format).

Alternatively, the base station 20 may set the L value, which is the number of times the random access response is repeated, and transmit the set L value to the MTC terminals in the cell through cell-specific RRC signaling. That is, the base station 20 may include the L value in the system information for the MTC terminal to broadcast to the MTC terminals in the cell.

Resource block allocation for RAR

Referring to FIG. 10, the terminal 10 determines a physical resource block (PRB) to which a random access response is allocated (S1010). The terminal 10 transmits the random access preamble to the base station 20 (S1020) and receives a random access response to the random access preamble through the PRB determined in step S1010 (S1030).

In one example, the PRB for RAR transmission may be allocated in a localized manner.

11 is a diagram illustrating an example of a resource block allocated for RAR transmission. Referring to FIG. 11, the number of PRBs (R _PRBs ) allocated for RAR transmission in one downlink subframe and the position (frequency position, or PRB index) of a corresponding PRB may be a fixed value. In one example, the value of R _PRB may be a natural number of 6 or less, and the location of the PRB may be the center frequency of the system band.

12 is a diagram illustrating another example of a resource block allocated for RAR transmission. Referring to FIG. 12, the number of PRBs allocated for RAR transmission (R _PRB ) is fixed, but the location of the PRB allocated for RAR transmission for each downlink subframe may be frequency hopping. When frequency hopping is applied to the RAR transmission, the location of the PRB allocated for the RAR transmission in each downlink subframe includes the bandwidth (number of PRBs, N _PRB ) of the corresponding system and the subframe index or slot number during the RAR transmission. Can be determined as a function of

In the embodiment of FIG. 10, the PRB allocated for RAR transmission is determined in advance or according to a preset rule. However, in another embodiment, the PRB allocated for RAR transmission may be set in the base station 20 and broadcast to MTC terminals in the cell through cell-specific RRC signaling.

Referring to FIG. 13, the terminal 10 receives information about a physical resource block (PRB) to which a random access response is allocated from the base station 20 (S1310). The terminal 10 transmits the random access preamble to the base station 20 (S1320) and receives a random access response to the random access preamble through the PRB determined in step S1310 (S1330).

In this case, the PRB allocation information for the corresponding RAR may be set in a bitmap manner for the PRB constituting the entire system bandwidth by reusing the existing PRB allocation signaling format for setting the EPDCCH set. In such a case, the corresponding PRB allocation may be allocated in a localized or distributed manner.

Or, when PRB information is allocated through cell-specific RRC signaling, together with the value of the number of PRBs allocated for RAR transmission (R _PRB ) and the R _PRB allocation information in a downlink subframe in which the first RAR transmission is made. , The value of the hopping size (H _PRB ) of the corresponding RAR may be signaled.

Referring to FIG. 14, the terminal 1400 includes a controller 1410, a transmitter 1420, and a receiver 1430.

The controller 1410 is a PDSCH resource allocation method for transmitting an RAR message for an MTC terminal required to perform the above-described embodiments. The control unit 1410 is not a dynamic scheduling through a PDCCH, but a quasi-static (for RAR) transmission. semi-static) Controls the operation of the UE according to the allocation of PDSCH resources.

The transmitter 1420 transmits uplink control information, data, and a message to a base station through a corresponding channel.

The receiver 1430 receives downlink control information, data, and a message from a base station through a corresponding channel.

In one embodiment, a subframe in which a random access response is transmitted may be set.

The receiver 1430, before transmitting the random access preamble, receives subframe information indicating a relationship between a subframe in which the terminal transmits the random access preamble and a subframe in which the terminal receives a random access response related to the random access preamble. Can be received.

The transmitter 1420 may transmit a random access preamble, and the receiver 1430 may receive a random access response related to the random access preamble through a subframe determined based on the subframe information.

The subframe information may include information indicating a difference between a subframe in which the terminal transmits a random access preamble and a subframe in which the terminal receives a random access response.

Alternatively, the subframe information may include information indicating the index of the subframe in which the terminal receives the random access response.

Alternatively, the subframe information may include information of a radio frame and information of a subframe in which the terminal receives a random access response.

In this case, the subframe information may include a plurality of candidate values, and the receiver 1430 may attempt to receive a random access response using each candidate value.

The random access preamble may be repeatedly received through a plurality of subframes. The number of the plurality of subframes may be determined based on at least one of the number of repetitive transmissions of the random access preamble and the format of the random access preamble. Alternatively, the receiver 1430 may receive information indicating the number of the plurality of subframes.

In another embodiment, a resource block to which a random access response is sent may be set.

The controller 1410 may determine a resource block to which a random access response is allocated.

The transmitter 1420 may transmit a random access preamble, and the receiver 1430 may receive a random access response related to the random access preamble through the determined resource block.

In one example, the number of resource blocks is pre-installed, and the location of the resource blocks may be determined based on at least one of a downlink bandwidth, an index of a subframe, and an index of a slot.

Alternatively, the receiver 1430 may receive information about a resource block to which a random access response is allocated.

Referring to FIG. 15, the base station 1500 includes a controller 1510, a transmitter 1520, and a receiver 1530.

The control unit 1510 is a PDSCH resource allocation method for transmitting an RAR message for an MTC terminal required to carry out the above-described present invention. The control unit 1510 is a quasi-static for RAR transmission, not dynamic scheduling through PDCCH. semi-static) Controls the operation of the overall base station according to the allocation of PDSCH resources.

The transmitter 1520 and the receiver 1530 are used to transmit and receive signals, messages, and data necessary for carrying out the present invention.

Before receiving the random access preamble, the transmitter 1520 receives subframe information indicating a relationship between a subframe in which the terminal transmits the random access preamble and a subframe in which the terminal receives a random access response related to the random access preamble. Can transmit

The receiver 1530 may receive a random access preamble.

After the random access preamble is received, the transmitter 1520 may transmit a random access response related to the random access preamble in a subframe determined based on the subframe information.

In this case, the subframe information may include a plurality of candidate values.

The random access preamble may be repeatedly transmitted through a plurality of subframes. The transmitter 1520 may transmit information indicating the number of the plurality of subframes.

Meanwhile, the terminal and the base station according to another embodiment of the present invention may perform the random access method described below. Embodiments of the present invention described above and embodiments of the present invention described below may be performed separately, or may be performed in combination.

LTE 단말을 위한 PDCCH search space 설정 식Formula for setting PDCCH search space for LTE terminal

In case of a UE configured to receive DCI through PDCCH in an existing 3GPP LTE / LTE-Advanced system, a set of PDCCH candidates defined to be monitored for receiving downlink control information in any downlink subframe k Search space for the corresponding terminal,

This is made up. At this time,

Aggregation level, L (where,

Any PDCCH candidate m with) is determined by Equation 1 below.

[Equation 1]

here

Has a value of and cross-carrier scheduling is set,

Has If cross carrier scheduling is not set,

Has the value of. (only,

Means a CIF (Carrier Indicator Field) value included in the DCI)

Has the value of,

Represents an aggregation level, the number of PDCCH candidates defined for the UE to monitor for L,

Denotes the number of control channel elements (CCEs) constituting a PDCCH control region in a corresponding DL subframe k.

In addition, in Equation 1 described above

The value is determined by Equation 2 below.

[Equation 2]

Where each

(

Has a slot number).

Meanwhile, as described above, the random access response to the random access preamble transmission of the terminal is transmitted through the downlink data channel, that is, the PDSCH. For example, the scheduling information for the corresponding random access response is configured in DCI format 1A or DCI format 1C, and is scrambled by a cyclic redundancy check (CRC) by a random access RNTI (RA-RNTI) to control a region. The PDCCH is transmitted through the Common Search Space (CSS). That is, in order to receive the random access response, which is a response message for the random access preamble transmission, the terminal must first decode the PDCCH including scheduling information about the random access response in CSS. In addition, at any base station, after receiving the random access preamble, it is possible to freely schedule the random access response within a certain time window.

For this reason, in the case of a random access response message, semi-static scheduling is defined to transmit a random access response through a fixed PDSCH resource without applying a conventional dynamic scheduling method through a conventional PDCCH. A solution is required. However, when semi-static scheduling is applied to the random access response, it may be difficult to allocate an appropriate amount of Physical Resource Block (PRB) according to the size of the random access response message.

In order to solve this problem, the present invention proposes a PDSCH resource allocation method and apparatus for transmitting a random access response message for an MTC terminal. In particular, when a semi-static scheduling method is applied without transmitting scheduling information through the PDCCH as a resource allocation method for transmitting a random access response, the number of PRBs to be allocated is dynamically changed according to the size of the random access response message. We propose a method and a device for adjusting dynamically.

That is, the present invention proposes a PDSCH resource allocation method and apparatus for transmitting a random access response for an MTC terminal. Specifically, a method of applying semi-static scheduling for fixing a random PDSCH resource for a random access response without transmitting PDSCH resource allocation information for transmitting a random access response message through a PDCCH is proposed. do. In addition, a method and apparatus for varying the number of allocated PRBs or the amount of resources according to the message size of the random access response will be proposed. To this end, the present invention proposes a blind detection based random access response message reception method according to the first embodiment and a random access response transmission / reception scheme through the EPDCCH according to the second embodiment.

Referring to FIG. 16, in order to improve random access preamble reception performance of a coverage limited MTC terminal in a base station, a method of newly defining a random access preamble format for an MTC terminal or repeatedly transmitting an existing random access preamble may be considered. Can be.

For example, in case of the coverage limited MTC terminal, the preamble generated based on the random access preamble format for the conventional general LTE / LTE-Advanced terminal may be repeatedly transmitted M times.

As another example, in the case of a coverage limited MTC terminal, a length of a preamble format defined over M uplink subframes (ie, a sum of CP length and sequence length of a preamble format, that is, a value of T _CP + T _SEQ or a sequence length) , A method of transmitting a preamble generated based on a new random access preamble format having an increased length of T _SEQ ) may be considered.

In addition, the base station may be considered to apply a semi-static scheduling method, rather than the conventional dynamic scheduling method, to allocate the RAR message transmission resource for the corresponding coverage limited MTC terminal.

As described above, in order to apply semi-static scheduling to the random access response, a PRB in which the corresponding random access response is transmitted in a DL subframe (s) in which the random access response is transmitted is specifically applied. A method of allocating (s) is required.

The terminal of the present invention described below means an MTC terminal or a coverage restriction terminal.

A base station according to an embodiment of the present invention receives a random access preamble from a terminal. The base station may configure a random access response related to the random access preamble based on the random access response message format, or configure a random access response EPDCCH set. Thereafter, the base station transmits a random access response to the terminal. For example, the random access response transmitted by the base station may be transmitted through a search space determined according to a random access response message format, and the search space may be formed in the data area. As another example, the random access response transmitted by the base station may be transmitted through the random access response EPDCCH set, and the EPDCCH set may be formed in the data region.

Specifically, the following two embodiments will be described as a method for allocating a PRB according to the size of a random access response message without transmitting scheduling information through the PDCCH.

First embodiment. Blind detection based RAR message reception for MTC UEs

In a method for performing a random access procedure, a base station according to an embodiment of the present invention comprises: receiving a random access preamble, configuring a random access response related to the random access preamble based on a random access response message format, and randomizing And sending the access response.

Referring to FIG. 17, the terminal 10 for random access attempt transmits a random access preamble to the base station 20 (S1710).

The base station 20 may receive the random access preamble and configure a random access response related to the received random access preamble based on the random access format (S1720).

Thereafter, the base station 20 may transmit a random access response configured according to a specific random access format (S1730). For example, the random access response may be transmitted through a search space set for each random access response message format.

As described above, in the first embodiment of the present invention, the random access response may be transmitted to the data region without scheduling the random access response through the PDCCH. In this case, the terminal can receive the random access response by decoding the search space that can be set according to the random access format by using the blind decoding method.

Referring to FIG. 18, the base station receives a random access preamble transmitted from the terminal (S1810).

For example, as described above, the UE may repeatedly transmit a random access preamble a predetermined number of times or transmit a preamble generated based on the new random access preamble format described above. The base station may receive the preamble generated based on the repeated or new random access preamble format.

The base station may configure a random access response related to the random access preamble based on a random access response message format (S1820).

For example, the random access response may be configured according to a random access response message format set differently according to the message size of the random access response to be transmitted by the base station. The base station may configure the random access response message through a suitable random access response message format among a plurality of random access response message formats.

Meanwhile, when configuring a CRC for a random access response message for an MTC terminal, the base station may configure a corresponding CRC by scrambling RA-RNTI or scrambles a part of the MSB or LSB of the RA-RNTI.

In this case, the RA-RNTI value of the random access response may be determined by one or more of the number of repetitions of the random access preamble and the random access response message format.

For example, the corresponding RA-RNTI may be defined by a higher layer in the same manner as the conventional method regardless of the random access response message format. That is, it may be defined based on a subframe number or slot number associated with the reception of the random access preamble.

As another example, the RA-RNTI may have a different value depending on the number of repetitions of the random access preamble or the random access response message format.

In addition, turbo coding, which is a channel coding scheme for the existing DL-SCH, may be equally applied as a channel coding scheme for a random access response message of the MTC terminal. Alternatively, the random access response message of the MTC terminal may apply a tail biting convolutional coding method which is an existing DCI channel coding method.

The base station may transmit the random access response configured in the above-described manner through the data region (S1830). That is, the random access response may be transmitted through the PDSCH, and may be transmitted through a search space that is not scheduled by the PDCCH but may be set based on a random access response message format.

19, in a first embodiment of the present invention, a plurality of random access response message formats may be defined for transmission of a random access response message for an MTC terminal.

For example, each random access response message format may include different numbers of PRB allocation information as shown in the table of FIG. 19. In detail, the random access response message format 0 may allocate the number of N ₀ PRBs, and the number of MCSs and the number of random access response candidates may correspond to each other.

19 exemplarily illustrates a random access response message format, and does not limit the number of specific random access response message formats and the number of PRBs values for each random access response message. . In addition, a fixed MCS may be used regardless of each random access response message format, or a different MCS may be defined for each random access response message format.

When transmitting a random access response message for the MTC terminal, the base station may configure and transmit the corresponding random access response through a suitable random access response message format among the plurality of random access response message formats defined above.

Hereinafter, the operation of the terminal in performing the random access procedure according to the first embodiment will be described with reference to the drawings.

In a method for performing a random access procedure by a terminal according to another embodiment of the present invention, transmitting a random access preamble and monitoring one or more search spaces set for each random access response message format or configuring a random access response EPDCH set Monitoring the random access response EPDCCH set based on the information and receiving a random access response related to the random access preamble according to the monitoring result.

Referring to FIG. 20, the terminal may transmit a random access preamble to perform a random access procedure (S2010). The terminal may repeatedly transmit the random access preamble or transmit the random access preamble over a plurality of subframes in order to satisfy the requirements of the aforementioned MTC terminal.

The terminal may monitor one or more search spaces set for each random access response message format (S2020).

For example, the UEs that transmit the random access preamble are random for the corresponding UE in a search space including random access response message candidates based on each random access response message format in the PDSCH region. Blind decoding may be performed on the access response message.

The terminal may receive a random access response to the random access preamble transmitted through the blind decoding as described above (S2030).

In order to receive a random access response to a random access preamble transmission, the terminal may transmit a random access response message in a PDSCH region of one or a plurality of downlink subframes (DL subframe (s)) that are expected to transmit a random access response for the corresponding terminal. A random access response may be received by performing blind decoding on a search space defined for each format.

For example, a Physical Resource Block (PRB) or Virtual Resource Block (VRB) index (or indices) constituting a search space for each RAR message format (v) defined to be monitored by the UE. ) Is the number of total PRBs (N _PRBs ), slot number, slot number, constituting the downlink system bandwidth, respectively.

), The number of PRBs (N _v ) constituting the RAR message format ( _v ), and a function such as RA-RNTI. That is, a PRB or VRB of a search space set for each random access response message format according to another embodiment of the present invention includes the total number of PRBs, slot numbers, and corresponding random access response message formats forming the downlink system bandwidth. It can be determined by the number of PRBs and a function of RA-RNTI.

As an example of this, the existing PDCCH search space expression described above may be reused. In this case, the PRB or VRB index (indices) of the PDSCH region constituting a search space for an arbitrary random access message response format (v) may be represented by Equation 1 described above.

N _PRB instead, N _v instead of L, and m '= m = 0,... It can be defined by applying M (v) -1. In this case, in Equation 2 to define the corresponding Y _k

Apply to

The RA-RNTI can be applied to the value.

As described above, according to the first embodiment of the present invention, when the terminal and the base station perform a random access procedure, the base station may transmit a random access response through a search space that can be defined for each random access response message format. . Accordingly, the terminal may receive the random access response by monitoring the corresponding PRB or VRB according to the PRB or VRB index of the search space which may be set based on the random access response message format.

According to the present invention, it is possible to prevent waste of PDCCH resources due to repetitive transmission. In addition, since the random access response is transmitted through the data area set according to the random access response message format rather than scheduled by the PDCCH, it is possible to reduce the consumption of radio resources due to repetitive transmission.

Second embodiment: Method for transmitting and receiving random access response through EPDCCH.

The base station according to another embodiment of the present invention may transmit on the EPDCCH in transmitting a random access response.

In a method for performing a random access procedure by a base station according to another embodiment of the present invention, the method may include receiving a random access preamble, configuring a random access response EPDCCH set, and transmitting a random access response. have.

Referring to FIG. 21, the terminal 10 may transmit a random access preamble to the base station 20 (S2110). The terminal 10 may repeatedly transmit the random access preamble or adjust and transmit the length of the random access preamble.

The base station 20 may configure a random access response EPDCCH set to transmit the random access response (S2120). That is, the base station 20 may configure a random access response EPDCCH set (RAR EPDCCH set) for transmitting a random access response message to the terminal 10.

The base station 20 may transmit a random access response by using the configured random access EPDCCH set (S2130).

A detailed operation of the base station will be described with reference to FIG. 22.

Referring to FIG. 22, the base station may receive a random access preamble from the terminal (S2210). The base station may receive a random access preamble repeatedly transmitted by the terminal, or may receive a random access preamble transmitted through a plurality of subframes.

The base station may configure a random access response EPDCCH set related to the received random access preamble (S2220). For example, the base station may configure an arbitrary EPDCCH set as a random access response EPDCCH set. The configured random access response EPDCCH set is configured for random access response transmission. The base station may configure the random access response EPDCCH set based on the configuration information for configuring the random access response EPDCCH set.

The base station may transmit a random access response (S2230). For example, the random access response may be transmitted through the configured random access response EPDCCH set.

Referring to FIG. 23, when the base station configures a random access response EPDCCH set, the base station may further include transmitting random access response EPDCCH set configuration information (S2330). For example, the base station may receive a random access preamble from the terminal (S2310), and configure a random access response EPDCCH set for the received random access preamble (S2320).

The base station may transmit configuration information used to configure the random access response EPDCCH set to the terminal (S2330).

For example, the configuration information may be transmitted to the terminal through cell-specific higher layer signaling. Specifically, it may be transmitted through cell-specific RRC signaling.

Or, the base station may implicitly configure a random access response EPDCCH set (RAR EPDCCH set).

When cell-specific RRC signaling for random access response EPDCCH set configuration is applied, corresponding cell-specific RRC signaling is unnecessary configuration information among existing EPDCCH set configuration RRC parameters for LTE / LTE-Advanced UE (for example, , pucch-ResourceStartOffset-r11, etc.) may contain only some information. Alternatively, some settings (for example, transmissionType, dmrs-ScramblingSequenceInt, resourceBlockAssignment, etc.) may be fixed and only some information except for them may be included.

Parameters included in the configuration information will be described in detail with reference to FIG. 24.

The base station may transmit a random access response through the configured EPDCCH set (S2340).

The base station may transmit the configuration information used to configure the random access response EPDCCH set to the terminal. The base station may transmit configuration information to the terminal through cell-specific higher layer signaling. Specifically, it may be transmitted through cell-specific RRC signaling.

For example, cell-specific RRC signaling includes only some information except for unnecessary configuration information (eg, pucch-ResourceStartOffset-r11, etc.) among existing EPDCCH set configuration RRC parameters for LTE / LTE-Advanced UE. can do. Alternatively, some settings (for example, transmissionType, dmrs-ScramblingSequenceInt, resourceBlockAssignment, etc.) may be fixed and only some information except for them may be included.

As illustrated in FIG. 24, the EPDCCH set configuration RRC parameter may include an information element related to the EPDCCH configuration.

In transmitting the random access response EPDCCH set configuration information to the terminal, the base station transmits some of the information of FIG. 24 or transmits some of the information of FIG. 24 and includes only the information except the fixed information. Can be.

The information element for EPDCCH configuration of FIG. 24 includes information on a subframe and resource block for EPDCCH monitoring configured by a base station for a serving cell.

Each information element in FIG. 24 includes the information in Table 1.

TABLE 1

As another example, the base station may implicitly configure the random access response EPDCCH set. That is, configuration information for configuring the corresponding random access response EPDCCH set may have a fixed value or may be determined as a function using a slot number and a RA-RNTI.

The operation of the terminal according to the second embodiment will be described with reference to FIG. 25.

The UE may transmit a random access preamble to perform a random access procedure (S2510). As described above, the UE may repeatedly transmit the random access preamble or configure and transmit the random access preamble through a plurality of subframes.

The UE may monitor the corresponding random access response EPDCCH set in order to receive the random access response to the random access preamble transmission (S2520). The UE may receive configuration information on the random access response EPDCCH set from the base station through higher layer signaling to monitor the random access response EPDCCH set.

The UE may receive a random access response through the random access response EPDCCH set monitoring (S2530).

A detailed method related to EPDCCH set monitoring for the UE to receive a random access response will be described by way of example with reference to FIGS. 26 and 27.

The UE may monitor a specific random access response EPDCCH set to receive a random access response. The random access response EPDCCH set monitored by the UE may be confirmed based on the above-described configuration information or information implicitly given.

For example, the UE may monitor and receive the random access response based on the random access response EPDCCH format and the number of random access response EPDCCH candidates according to each random access response EPDCCH format.

FIG. 26 exemplarily shows the number of EREGs per ECCE, and FIG. 27 exemplarily shows an EPDCCH format.

Referring to FIGS. 26 and 27, the number of random access response EPDCCH candidates to be monitored for each random access response EPDCCH format transmitted through the random access response EPDCCH set and the number of RAR EPDCCH candidates for each random access response EPDCCH format are known. The EPDCCH format defined for the LTE / LTE-Advanced UE and the number of EPDCCH candidates to be monitored by the UE for each EPDCCH format may be the same.

For example, FIG. 27 shows the number of ECCEs for one EPDCCH set for each EPDCCH format. That is, in the case of Case A when the EPDCCH format is 0, the number of ECCEs for one EPDCCH may be set to 2 regardless of localized or distributed transmission. In addition, in case B, the number of ECCEs for one EPDCCH may be set to 1 regardless of localized or distributed transmission.

Meanwhile, FIG. 26 is a diagram illustrating the number of EREGs per ECCE. Accordingly, the number of EREGs per ECCE may be determined according to the cyclic prefix and the type of subframe as shown in the table of FIG. 26.

As such, the UE may monitor the random access response EPDCCH set based on the EPDCCH format and the number of candidates for each EPDCCH format.

In the above, the case where it is the same as the EPDCCH format and the number of candidates per format of the existing LET / LTE-Advanced UE has been described as an example. However, the random access response EPDCCH format and the number of candidates per format may be separately set for the terminal of the present invention. .

Accordingly, the present invention does not specifically limit the number of random access response EPDCCH formats and the number of random access response EPDCCH candidates.

Unlike the method of performing the monitoring by receiving the configuration information of the random access response EPDCCH set described above, the UE may configure the random access response EPDCCH set to be monitored by using an implicit method.

For example, the UE may implicitly obtain and monitor configuration information of a random access response EPDCCH set to be monitored. That is, monitoring may be performed using preset or fixed random access response EPDCCH set configuration information, or monitoring may be performed based on a function using a slot number and a RA-RNTI for transmitting a random access preamble. have.

As described above, in the random access procedure of the present invention, the UE and the base station may configure a random access response using an EPDCCH set, and transmit and receive a random access response through the configured EPDCCH set.

Through this, it is possible to prevent radio resource waste of the control area due to repeated transmission of the random access response of the base station, and efficient use of radio resources may be possible.

In addition, the two random access response transmission / reception methods proposed by the present invention are not limited to the number of random access response repetitions (RAR repetition) and timing relation between random access preamble transmission and RAR reception for the UE. Can be applied. That is, regardless of a method of defining a downlink subframe for transmitting a random access response, all may be applied.

The configuration of a base station and a terminal in which both of the above-described present invention can be performed will be described below by way of example.

Referring to FIG. 28, a base station 2800 performing a random access procedure according to another embodiment of the present invention may include a receiver 2830 that receives a random access preamble and a random access preamble based on a random access response message format. It may include a control unit 2810 for configuring a related random access response or a random access response EPDCCH set and a transmitter 2820 for transmitting a random access response.

When the random access response is configured based on the random access response message format, which is the case of the first embodiment described above, the transmitter 2820 may transmit the random access response through a search space set for each random access response message format.

The control unit 2800 controls the PRB or VRB of the search space set for each random access response message format, the total number of PRBs constituting the downlink system bandwidth, the slot number, the number of PRBs of the corresponding random access response message format, and the RA-RNTI. Can be determined by the function of.

In addition, when the random access response is configured based on the random access response message format, the RA-RNTI value of the random access response may be determined by one or more of the number of repetitions of the random access preamble and the random access response message format.

Meanwhile, when configuring the random access response EPDCCH set according to the second embodiment, the transmitter 2820 may transmit the random access response through the random access response EPDCCH set.

In addition, when configuring a random access response EPDCCH set, the transmitter 2820 may further transmit the random access response EPDCCH set configuration information. The random access response EPDCCH set configuration information may be transmitted through cell specific higher layer signaling. Or it may be implicitly confirmed to the terminal.

In addition, the controller 2810 controls the overall operation of the base station according to the PDSCH resource allocation for the random access response transmission for the MTC terminal required to perform the above-described present invention.

The transmitter 2820 and the receiver 2830 are used to transmit and receive signals, messages, and data necessary for carrying out the above-described present invention.

Referring to FIG. 29, a terminal 2900 for performing a random access procedure according to another embodiment of the present invention may include at least one search space configured for a transmitter 2920 for transmitting a random access preamble and a random access response message format. Or a controller 2930 for monitoring the random access response EPDCCH set based on the random access response EPDCH set configuration information, and a receiver 2930 for receiving a random access response related to the random access preamble according to the monitoring result. .

The PRB or VRB of the search space set for each random access response message format, which is the case of the first embodiment described above, includes the total number of PRBs constituting the downlink system bandwidth, the slot number, and the number of PRBs in each random access response message format. And a function of RA-RNTI. In addition, the RA-RNTI value of the random access response may be determined by one or more of the number of repetitions of the random access preamble and the random access response message format.

Meanwhile, in the case of the second embodiment, the receiver 2930 may further receive the random access response EPDCCH set configuration information through cell-specific higher layer signaling.

In addition, the monitored random access response EPDCCH set may be set separately for each random access response EPDCCH format.

In addition, the control unit 2910 controls the overall operation of the terminal receiving the random access response transmitted according to the PDSCH resource allocation for the random access response transmission for the MTC terminal required to perform the present invention described above.

The transmitter 2920 and the receiver 2930 are used to transmit and receive signals, messages, and data necessary for carrying out the above-described present invention.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

CROSS-REFERENCE TO RELATED APPLICATIONCROSS-REFERENCE TO RELATED APPLICATION

This patent application is filed with Korea Patent Application No. 10-2013-0120267 filed on October 10, 2013 and Korea Patent Application No. 10-2013-0132334 filed on November 1, 2013, and July 2014 119 (a) (35 USC §) to US Patent Application No. 10-2014-0084249 filed with Korea on 07 and Patent Application No. 10-2014-0099563 filed with Korea on August 04, 2014 (35 USC § Priority is claimed under 119 (a)), the contents of which are hereby incorporated by reference in their entirety. In addition, if this patent application claims priority for the same reason for countries other than the United States, all its contents are incorporated into this patent application by reference.

Claims

As a method for receiving a random access response by the terminal,

Receiving subframe information indicating a relationship between a subframe in which the terminal transmits a random access preamble and a subframe in which the terminal receives a random access response related to the random access preamble;

Transmitting the random access preamble;

Receiving a random access response related to the random access preamble on a subframe determined based on the subframe information.
The method of claim 1,

The subframe information includes information indicating a difference between a subframe in which the terminal transmits the random access preamble and a subframe in which the terminal receives the random access response.
The method of claim 1,

The subframe information includes information indicating an index of a subframe in which the terminal receives the random access response.
As a method for receiving a random access response by the terminal,

Determining a resource block to which a random access response is assigned;

Transmitting a random access preamble; And

Receiving a random access response related to the random access preamble via the determined resource block.
A method for transmitting a random access response by a base station,

Transmitting subframe information indicating a relationship between a subframe in which the terminal transmits a random access preamble and a subframe in which the terminal receives a random access response related to the random access preamble;

Receiving a random access preamble;

Transmitting a random access response related to the random access preamble on a subframe determined based on the subframe information.
The method of claim 5,

The subframe information includes information indicating a difference between a subframe in which the terminal transmits the random access preamble and a subframe in which the terminal receives the random access response.
The method of claim 5,

The subframe information includes information indicating an index of a subframe in which the terminal receives the random access response.
A method for transmitting a random access response by a base station,

Transmitting information on a resource block to which a random access response is allocated to the terminal;

Receiving a random access preamble;

Transmitting a random access response related to the random access preamble on the resource block.
A terminal for receiving a random access response,

A transmitter for transmitting a random access preamble; And

A receiver configured to receive a random access response related to the random access preamble through a subframe determined based on subframe information,

The receiving unit indicates a relationship between a subframe in which the terminal transmits the random access preamble and a subframe in which the terminal receives the random access response related to the random access preamble before transmitting the random access preamble. And receiving the subframe information.
A terminal for receiving a random access response,

A controller for determining a resource block to which a random access response is allocated;

A transmitter for transmitting a random access preamble; And

And a receiver configured to receive a random access response related to the random access preamble through the determined resource block.
A base station for transmitting a random access response,

A receiver for receiving a random access preamble; And

A transmitter for transmitting a random access response related to the random access preamble,

The transmitter is a subframe indicating a relationship between a subframe in which the terminal transmits the random access preamble and a subframe in which the terminal receives a random access response related to the random access preamble before receiving the random access preamble. A base station for transmitting frame information.
A base station for transmitting a random access response,

A receiver for receiving a random access preamble; And

A transmitter for transmitting a random access response related to the random access preamble,

The transmitter, before receiving the random access preamble, the base station, characterized in that for transmitting to the terminal information on the resource block to which the random access response is assigned.
In the method for the base station performs a random access procedure,

Receiving a random access preamble;

Configuring a random access response related to the random access preamble or configuring a random access response EPDCCH set based on a random access response message format; And

Sending the random access response.
The method of claim 13,

When the random access response is configured based on the random access response message format, the random access response is transmitted through a search space set for each random access response message format.
The method of claim 13,

When the random access response is configured based on the random access response message format, the RA-RNTI value of the random access response is determined by one or more of the number of repetitions of the random access preamble and the random access response message format. .
In a method for performing a random access procedure by the terminal,

Transmitting a random access preamble;

Monitoring at least one search space set for each random access response message format or monitoring the random access response EPDCCH set based on random access response EPDCH set configuration information; And

Receiving a random access response related to the random access preamble according to the monitoring result.
The method of claim 16,

The PRB or VRB of the search space set for each random access response message format is a function of the total number of PRBs constituting the downlink system bandwidth, the slot number, the number of PRBs of the corresponding random access response message format, and the RA-RNTI. How is determined.
The method of claim 16,

The RA-RNTI value of the random access response is determined by one or more of the number of repetitions of the random access preamble and the random access response message format.
In the base station performing a random access procedure,

A receiver for receiving a random access preamble;

A controller configured to configure a random access response related to the random access preamble or a random access response EPDCCH set based on a random access response message format; And

A base station comprising a transmitter for transmitting the random access response.
In a terminal performing a random access procedure,

A transmitter for transmitting a random access preamble;

A controller for monitoring one or more search spaces set for each random access response message format or monitoring the random access response EPDCCH set based on random access response EPDCH set configuration information; And

And a receiver configured to receive a random access response related to the random access preamble according to the monitoring result.