KR20170083707A - Apparatus and method of control channel transmission for NB-IoT - Google Patents

Abstract

The present embodiments provide an ECCE-EREG mapping rule based on an operation mode in which the number of EREG or NB-REG constituting one ECCE or NB-CCE constituting a transmission unit of the NB-PDCCH is varied according to the operation mode of the NB-IoT terminal Thereby maximizing multiplexing capability for a plurality of NB-IoT terminals and minimizing unnecessary resource allocation in transmission of one NB-PDCCH even in one PRB.

Description

[0001] Apparatus and method for control channel transmission for NB-IoT terminal [

The present invention proposes a method for transmitting and receiving a downlink control channel for a NarrowBand Internet of Things (NB-IoT) terminal in a 3GPP LTE / LTE-A system.

In one embodiment, an ECCE-EREG mapping rule based on an operation mode in which the number of EREG or NB-REG constituting one ECCE or NB-CCE constituting a transmission unit of the NB-PDCCH is varied according to an operation mode of the NB- .

Another embodiment is a method for transmitting an NB-PDCCH configured with a small number of REs, and can be defined to support a 1 / N-based aggregation level less than 1 for an NB-IoT terminal.

1 shows an EREG indexing for a PRB pair (when CRS port 0 is set)
2 shows an EREG indexing for a PRB pair (when CRS port 0,1 is set)
3 illustrates EREG indexing for a PRB pair (when CRS ports 0, 1, 2, and 3 are set)
4 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.
5 is a diagram illustrating a configuration of a user terminal according to another embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

According to a Resource Element (RE) allocation method for transmission and reception of EPDCCH (Enhanced Physical Downlink Control Channel) defined in the 3GPP LTE / LTE-A rel-11 system, a total of 16 EREGs (Enhanced Resource-Element Groups) have been configured. RSs corresponding to the antenna port p = {107,108,109,110} for the normal CP and the antenna port p = {107,108} for the extended CP, as shown in FIGS. 1 to 3, EREG-RE mapping is performed in increasing order in frequency-first manner for all REs except for REs used for RRE.

However, in Fig. 1 to Fig. 3, the hatched grating portion indicates RE used for DM RS, and the filled portion indicates REs to which CRS is transmitted.

In addition, a specific description of the EPDCCH transmission / reception method based on the EREG structure described above is attached to the respective contents of TS 36.211 and TS 36.213 through Attachment 1 and Attachment 2.

[NB-IoT]

1.1 4 Objective

1.1.1 4.1 Objective of SI or Core part WI or Testing part WI

The objective is to provide a wireless access for the cellular internet of things, based on a non-backward-compatible variant of E-UTRA, that addresses improved indoor coverage, , ultra low device cost, low device power consumption and (optimized) network architecture.

NB-IOT should support 3 different modes of operation:

One. 'Stand-alone operation' is used for example in the spectrum currently being used by GERAN systems as a replacement for one or more GSM carriers

2. 'Guard band operation' using the unused resource blocks within a LTE carrier's guard-band

3. 'In-band operation' utilizing resource blocks within a normal LTE carrier

In particular, the following will be supported:

● 180 kHz UE RF bandwidth for both downlink and uplink

● OFDMA on the downlink

     o Two numerology options will be considered for inclusion: 15 kHz sub-carrier spacing (with normal or extended CP) and 3.75 kHz sub-carrier spacing. Technical analysis will either perform a down-selection or inclusion of both based on the feasibility of meeting relevant requirements while achieving commonality (to be finalized by RAN # 70)

FDMA with GMSK modulation (as described in 3GPP TR 45.820 section 7.3), and SC-FDMA (including single-tone transmission as a special case of SC-FDMA)

     o Technical analysis will either perform a down-selection or decide on inclusion of both

● A single synchronization signal design for different modes of operation, including techniques to handle overlapping legacy LTE signals

● MAC, RLC, PDCP and RRC procedures based on existing LTE procedures and protocols

      ● Any enhancements to S1 interface to CN and related radio protocols to support the work.

In the present invention, for the sake of convenience of description, "NB-" is prefixed to distinguish the downlink control channel or terminology for the NB-IoT having the same function as the existing LTE-related downlink control channel or terminology, The meaning can be mixed.

As described above, since the NB-IoT UE is implemented based on the UE RF bandwidth of 180 kH, only the reception of the frequency resource corresponding to one PRB pair is possible. In addition, when the NB-IoT terminal is introduced, reduction of the DCI overhead is required compared with the existing LTE terminal because support for the massive number of low throughput devices is required. In this case, the NB-PDCCH PDCCH) or the NB-CCE or E-CCE size which is the transmission unit of the EPDCCH.

The present invention proposes a method for transmitting NB-PDCCH, which is a downlink control channel for an NB-IoT terminal.

In the existing EPDCCH, up to two EPDCCH sets composed of 2, 4, and 8 PRB pairs can be configured in the base station through RRC signaling, and can be set for each UE. However, since the reception bandwidth is limited to 1 PRB pair in the case of the NB-IoT terminal, it is impossible to apply the PRB pair allocation method for the existing EPDCCH set configuration. In addition, when the NB-IoT terminal is introduced, since it is required to support massive number of low throughput devices, it is possible to maximize the multiplexing capability for a plurality of NB-IoT terminals even within 1 PRB, It is necessary to redefine the NB-CCE (NB Control Channel Element), which is an NB-PDCCH transmission unit.

For convenience of description, the present invention will be described on the basis of the case where the NB-PDCCH reuses the structure of the EPDCCH EREG.

The first embodiment is an ECCE-EREG mapping method based on Operation mode.

The number of REs available for the NB-IoT terminal in one subframe is changed according to the operation mode of the NB-IoT terminal. In the in-band operation mode, 1 to 3 symbols or 2 to 4 symbols preceding the downlink subframe for the normal LTE / LTE-A terminal are used for transmission of the downlink control channel (PDCCH, PCFICH, PHICH) Since various RSs such as CRS, CSI-RS and PRS can be transmitted through the corresponding downlink subframe, the number of REs that can be used for NB-IoT within a single PRB pair is limited. On the other hand, in the guard-band operation mode and the stand-alone operation mode, since the REs of the first OFDM symbol of all downlink subframes can be used for the NB-IoT terminal, the number of available REs More.

Therefore, we propose an ECCE-EREG mapping rule based on operation mode that changes the number of EREG or NB-REG constituting one ECCE or NB-CCE that is the transmission unit of NB-PDCCH according to operation mode.

According to the existing ECCE-EREG mapping method, the number of EREGs constituting one ECCE is determined by CP length and subframe type as shown in Table 1 below.

In the present invention, the number of the NB-CCEs or the number of the NB-REGs or the EREGs constituting the ECCEs may be determined according to the operation mode. For example, as shown in Table 2 below, the number of NB-REGs or EREGs constituting one NB-CCE or ECCE may be different according to the operation mode in addition to the CP length and subframe type.

However, the number of NB-CCEs or EREGs constituting the corresponding NB-CCE or ECCE in Table 2 below is only one example, and NB-REG or EREG number constituting one NB-CCE or ECCE regardless of its concrete value all cases in which the operation mode is determined as one parameter can be included in the scope of the present invention.

The second embodiment defines a 1 / N aggregation level.

As a method for transmitting NB-PDCCH composed of few REs, it can be defined to support a 1 / N-based aggregation level less than 1 for NB-IoT terminal. For example, according to the existing EPDCCH or PDCCH transmission method, the aggregation level 1 in which the corresponding EPDCCH or PDCCH is transmitted through one ECCE or CCE is the minimum transmission unit. In the case of the NB-IoT terminal, 1/2 ECCE or 1/4 It can be defined to support aggregation level 1/2 or 1/4 for ECCE based transmission.

For example, when the NB-PDCCH based on the aggregation level 1/2 is transmitted to the ECCE consisting of EREG # 0, # 4, # 8, and # 12, EREG # 0,4 or EREG # 8,12 Or EREG # 0,8 or EREG # 4,12, respectively.

Or a 1/4 aggregation level is supported, the NB-PDCCH can be defined to be transmitted through one EREG such as # 0 or # 4 or # 8 or # 12, respectively. However, the NB-CCE or ECCE segmentation method according to the aggregation level smaller than 1 is one embodiment, but not limited thereto, and all cases in which any 1 / N-based aggregation level smaller than 1 are supported, May be included in the category.

In addition, the aggregation level of the NB-PDCCHs to be monitored by each NB-IoT UE may be differently defined according to the operation mode.

For example, in the case of the existing EPDCCH, the number of EPDCCH candidates for each aggregation level and aggregation level defined for monitoring by the UE according to the number of set EPDCCH sets and the size of each EPDCCH set, that is, the number of PRBs constituting the corresponding EPDDCCH set It was decided. However, if the size of the EPDCCH or the NB-PDCCH set is determined in units of sub-carrier groups smaller than 1 PRB or the number of PRBs constituting the EPDCCH or NB-PDCCH set is determined to be 1 in the case of the NB-IoT UE, In addition to the size of the PDCCH set and the number of NB-PDCCH sets, the aggregation level to be monitored by the corresponding NB-IoT terminal and the number of NB-PDCCH candidates for each aggregation level may be determined according to the operation mode.

Or the aggregation level to be monitored by the corresponding NB-IoT UE according to one or more of the size of the NB-PDCCH set, the number of the NB-PDCCH set, the operation mode and the coverage level of the NB- The number of NB-PDCCH candidates can be determined.

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

Referring to FIG. 4, a base station 1000 according to another embodiment includes a control unit 1010, a transmission unit 1020, and a reception unit 1030.

The control unit 1010 may be configured to perform an ECCE-based ECCE or NB-CCE based on an operation mode in which the number of EREGs or NB-REGs constituting a transmission unit of the NB-PDCCH is changed according to an operation mode necessary for performing the above- And controls the overall operation of the base station according to the EREG mapping rule.

* Messages, and data to and from the terminal.

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

5, the user terminal 1100 according to another embodiment includes a receiving unit 1110, a control unit 1120, and a transmitting unit 1130.

The receiving unit 1110 receives downlink control information, data, and messages from the base station through the corresponding channel.

In addition, the controller 1120 may determine whether the ECCE of the NB-PDCCH or the ECCE of the operation mode based on the number of the EREG or the NB-REG constituting the NB-CCE according to the operation mode necessary for performing the above- Controls the overall operation of the terminal according to the -EREG mapping rule.

The transmitter 1130 transmits uplink control information, data, and a message to the base station through the corresponding channel.

The standard content or standard documents referred to in the above-mentioned embodiments constitute a part of this specification, for the sake of simplicity of description of the specification. Therefore, it is to be understood that the content of the above standard content and some of the standard documents is added to or contained in the scope of the present invention, as falling within the scope of the present invention. Includes the specification contents section 5.5 of 36.211 v.10.4.0 for the reference signal for uplink demodulation.

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

Claims (1)

Confirming an operation mode of the NB-IoT terminal; And
Setting one ECCE as a transmission unit of the NB-PDCCH and an EREG or NB-REG constituting the NB-CCE differently according to the operation mode;
And transmitting the control channel to the NB-IoT terminal.

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