KR20180046444A - Apparatus and method of slow DCI configuration in a short TTI frame structure - Google Patents

Abstract

In the present invention, by setting an effective period of DCI transmitted through legacy PDCCH in a 3GPP LTE/LTE-A system, a specific operation for DCI/sDCI detection for a short TTI terminal can be defined. A method for setting slow DCI in a short TTI frame structure comprises the steps of: receiving slow DCI having a set effective period through legacy PDCCH; performing a short TTI service based on the slow DCI only within a subframe in which the slow DCI is first received when the effective period of the slow DCI is one subframe; and performing the short TTI service based on an effective range of the slow DCI received through an RRC message when the effective period of the slow DCI is a plurality of subframes.

Description

[0001] The present invention relates to a method of setting a slow DCI in a short TTI frame structure,

The present embodiments relate to a method for setting a valid period of a DCI transmitted over a legacy PDCCH in a 3GPP LTE / LTE-A system.

According to an embodiment of the present invention, there is provided a method of setting a slow DCI in a Short TTI frame structure, the method comprising: receiving a slow DCI having a validity period set via a legacy PDCCH; receiving a slow DCI when the effective DCI period is one subframe; Performing a short TTI service based on a slow DCI only in one subframe; and performing a short TTI service based on an effective range of a slow DCI received through an RRC message when the effective period of the slow DCI is a plurality of subframes The method comprising the steps of:

1 is a diagram illustrating eNB and UE processing delays and HARQ RTT.
2 shows a resource mapping per PRB in one subframe.
3 is a conceptual diagram of a definition of a search space.
4 is a conceptual diagram of a common search space definition.
5 is a conceptual diagram of definition of a UE-specific search space.
FIG. 6 is a conceptual diagram of application of in-subframe level slow-DCI according to Method 1. FIG.
FIG. 7 is a conceptual diagram of application of multi-subframe level slow-DCI according to Option 2.
8 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.
9 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) the device itself providing a megacell, macrocell, microcell, picocell, femtocell, small cell in relation to the wireless region, or ii) indicating the wireless region itself. i indicate to the base station all devices that are controlled by the same entity or that interact to configure the wireless region as a collaboration. An eNB, an RRH, an antenna, an RU, an LPN, a point, a transmission / reception point, a transmission point, a reception point, and the like are exemplary embodiments of a base station according to a configuration method of a radio area. ii) may indicate to the base station the wireless region itself that is to receive or transmit signals from the perspective of the user terminal or from a neighboring base station.

Therefore, a base station is collectively referred to as a base station, collectively referred to as a megacell, macrocell, microcell, picocell, femtocell, small cell, RRH, antenna, RU, low power node do.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[Latency reduction in RAN1]

The Latency reduction Study Item was approved at RAN plenary # 69 meeting [1]. The main purpose of latency reduction is to standardize shorter TTI operations to foster TCP throughput [2]. For this purpose, performance verification for short TTI has already been performed in RAN2 [2].

Potential impacts and studies related to RAN1 are performed in the following ranges [1]:

o TTI lengths between 0.5ms and one OFDM symbol, taking into account the impact on reference signals and physical layer control signaling

o backwards compatibility shall be preserved (thus allowing normal operation of pre-Rel 13 UEs on the same carrier);

Latency reduction can be achieved by the following physical layer techniques:

- short TTI

- reduced processing time in implementation

- new frame structure of TDD

Additional agreements at the 3GPP RAN WG1 # 84 meeting are as follows.

Agreements:

● Following design assumptions are considered:

o No shortened TTI spans over subframe boundary

o At least for SIBs and paging, PDCCH and legacy PDSCH are used for scheduling

● The potential specific impacts for the followings are studied

o UE is expected to receive a SDSCH at least for downlink unicast

   ■ sPDSCH refers PDSCH carrying data in a short TTI

o UE is expected to receive PDSCH for downlink unicast

   ■ FFS whether a UE is expected to receive both PDSCH and PDSCH for downlink unicast simultaneously

o FFS: The number of supported short TTIs

o If the number of supported TTIs is more than one,

Agreements:

● Following design assumptions are used for the study

o From eNB perspective, existing non-sTTI and sTTI can be FDMed in the same subframe in the same carrier

   ■ FFS: Other multiplexing method (s) with existing non-sTTI for UE supporting latency reduction features

Agreements:

● In this study, the following aspects are assumed in RAN1.

o PSS / SSS, PBCH, PCFICH and PRACH, Random access, SIB and Paging procedures are not modified.

● Following aspects are further studied in the next RAN1 meeting

o Note: The study is not limited to them.

o Design of sPUSCH DM-RS

   ■ Alt.1: DM-RS symbol shared by multiple short-TTIs within the same subframe

   ■ Alt.2: DM-RS contained in each sPUSCH

o HARQ for SPUSCH

   ■ Whether / how to realize asynchronous and / or synchronous HARQ

o sTTI operation for Pcell and / or SCells by (e) CA in addition to non (e) CA case

Additional agreements at the 3GPP RAN WG1 # 84bis meeting are as follows.

Working Assumption:

- 1-OFDM-symbol sTTI length will not be further studied

Agreement:

● s PDCCH (short PDCCH) needs to be short for TTI.

   - Each short TTI on DL may contain sPDCCH decoding candidates

Working Assumption:

● CRS-based sPDCCH is recommended to be supported

   - FFS whether CRS-based sPDCCH can be transmitted in the legacy PDCCH region

● DMRS-based sPDCCH is recommended to be supported

● Design of both CRS-based sPDCCH and DMRS-based sPDCCH will be studied further.

Conclusions:

● A maximum number of BDs will be defined for sPDCCH in USS

   - In case 2-level DCI is adopted, any DCI for sTTI scheduling carried on PDCCH may be taken into account in the maximum total number of BDs

● FFS whether the maximum number is dependent on the sTTI length

● FFS whether the maximum number of blind decodes for (E) PDCCH is reduced in subframes in which the UE is expected to perform blind decodes for sPDCCH

● FFS whether a UE may be expected to monitor both EPDCCH and sPDCCH in the same subframe

● FFS whether the maximum number of BDs on PDCCH is changed from the legacy number

●  if DCI on PDCCH is for sTTI scheduling

Conclusion for study till RAN1 # 85:

● Two-level DCI can be studied for sTTI scheduling, where:

   - DCI for sTTI scheduling can be divided into two types:

      ● &Quot; Slow DCI ": DCI content is applied to more than 1 < RTI ID = 0.0 >

           ● FFS whether "Slow DCI" is UE-specific or common for multiple UEs

      ● &Quot; Fast DCI ": DCI content is applied to a specific < RTI ID = 0.0 >

      ● For a sPDSCH in a given sTTI, the scheduling information is obtained from either:

           ● a combination of slow DCI and fast DCI, or

           ● fast DCI only, overriding the slow DCI for that sTTI

- Compare with single-level DCI carried on one sPDCCH or one legacy PDCCH.

- DCI also includes some resource allocation information for the sPDCCH.

● Methods for reducing the overhead of single-level DCI can also be studied

     - Single-level DCI multi-sTTI scheduling for a variable number of sTTIs may be included

Aim to reduce the number of schemes under consideration at RAN1 # 85.

Agreements:

● Both CRS based and DMRS based TMs are recommended for DL sTTI transmission

 - No change for CRS definition

      ● FFS: Supporting more than 2 layers for sPDSCHs

 - Further study is needed about DMRS design (s) for sPDSCH demodulation

      ● For a certain TTI length, increased PRB bundling sizes may be necessary to achieve sufficient channel estimation accuracy.

      ● FFS: the number of DMRS antenna ports that can be supported for a given short-TTI length.

      ● For a certain TTI length, the new DMRS design (s) may be needed

Agreements:

● A UE is expected to handle the following cases in the same carrier in a subframe

- Receiving legacy TTI non-unicast PDSCH (except FFS for SC-PTM) and short TTI unicast PDSCH

- Receiving legacy TTI non-unicast PDSCH (except FFS for SC-PTM) and legacy TTI unicast PDSCH (s)

● FFS between:

- Alt 1: A UE is not expected to receive legacy TTI unicast PDSCH and short TTI unicast PDSCH simultaneously on one carrier

- TTI unicast PDSCH and short TTI Unicast PDSCH simultaneously on one carrier, then it may skip the decoding of one of them (FFS rules for determining which one)

- Sub 3: A UE is expected to receive legacy TTI unicast PDSCH and short TTI unicast PDSCH simultaneously on one carrier

● FFS UE behaviors in case of being scheduled with legacy TTI unicast PDSCH and short TTI unicast PDSCH simultaneously with legacy TTI non-unicast PDSCH (except FFS for SC-PTM) on the same carrier

● A UE can be dynamically (with a subframe to subframe granularity) scheduled with legacy TTI unicast PDSCH and / or (on on outcome of FFS above) short TTI PDSCH unicast

Agreements:

● A UE can be dynamically (with a subframe to subframe granularity) scheduled with PUSCH and / or sPUSCH

- A UE is not expected to transmit PUSCH and short TTI sPUSCH are same on the same REs, i.e. by superposition

- FFS whether a UE may transmit PUSCH and short TTI sPUSCH in the same subframe on one carrier by puncturing PUSCH

- FFS whether a UE may transmit PUSCH and short TTI sPUSCH in different PRBs on the same symbol (s)

- Dropping / prioritization rules (if any) are FFS

Agreements:

● It is recommended to support PHICH-less asynchronous UL HARQ for PUSCH scheduled in a short TTI (i.e. for SPUSCH)

● If DL data transmission is scheduled in a short TTI, the processing time for the HARQ feedback by UE and the processing time for preparing a potential retransmission by eNB are assumed to be reduced

- FFS: the extent of processing time reduction

● If UL data transmission is scheduled in a short TTI, the processing time for preparing UL data transmission on UL is delayed by a UE and the processing time for scheduling a potential retransmission by eNB is assumed to be reduced

- FFS: the extent of processing time reduction

● Study whether it is beneficial to limit TA value supported in conjunction with latency reduction

- Note that this would restrict the deployment scenarios for latency reduction.

● FFS processing time reductions can also be applied to legacy TTI transmissions for UEs that support short TTI

Basically, in the average down-link latency calculation, the latency is calculated according to the following procedure [3].

Figure 1: Assuming the 3GPP TR 36.912, the LTE U-plane one-way latency for a scheduled UE consists of fixed node processing delays and 1 TTI duration for transmission. processing times can be scaled by the same factor of TTI reduction keeping the same number of HARQ processes, the one way latency can be calculated as

D = 1.5 TTI + 1 TTI + 1.5 TTI UE + n * 8 TTI (HARQ retransmissions)

    = (4 + n * 8) TTI.

Considering a typical case where there would be 0 or 1 retransmission, and assuming error probability of the first transmission to be p, the delay is given by

D = (4 + p * 8) TTI.

So, for 0% BLER, D = 4 * TTI,

And for 10% BLER, D = 4.8 * TTI.

Average UE  initiated UL transmission latency calculation

Assume UE is in connected / synchronized mode and wants to do UL transmission, e.g., send to TCP ACK. The following table shows the steps and their corresponding contribution to the UL transmission latency. To be consistent in comparison of DL and UL, we add the eNB processing delay in the UL after the UL data is received by the eNB (step 7).

In the table above, steps 1 and 4 and half of the step 5 are assumed to be due to SR, and the rest is assumed to be shown in Table 4

Resource mapping of short TTI  [3]

In Figure 2 the resource map above is the legacy resource mapping per PRB in one subframe, considering 2 Antenna ports and 2 OFDM symbols control field. In Figure 2 the resource map below is the short TTI resource mapping, considering 2 OFDM symbols used for the control field in order to ensure the backward compatibility. The loss rates (L _legacy , eg 5% - 50%) of the PHY layer are short TTI duration are assumed.

TBS Calculation of short TTI

According to the present invention, the PDSCH is calculated as follows:

For different short TTI duration, The TBS of short TTI PDSCH is calculated as the following table:

The work scope of the recently shortened TTI Work item and the 3GPP RAN WG1 # 86 meeting were further agreed upon as follows.

For Frame structure type 1: [RAN1, RAN2, RAN4]

      ● Specify support for a transmission duration based on 2-symbol sTTI and 1-slot sTTI for sPDSCH / sPDCCH

      ● 2-symbol sTTI, 4-symbol sTTI, and 1-slot sTTI for sPTICH / sPTCH

o Down-selection is not precluded

 ● Study any impact on CSI feedback and processing time, and if necessary, specify necessary modifications (not before RAN1 # 86bis)

Agreement:

 ● For FS1, 2 & 3, a minimum timing n + 3 is supported for UL grant to UL data and DL data to DL HARQ for UEs capable of operating with reduced processing time with only the following conditions:

     ● A maximum TA is reduced to x ms, where x < = 0.33ms (exact value FFS);

     ● At least when scheduled by PDCCH

 ● For FS2, new DL HARQ and UL scheduling timing relations will be defined

     ● Details FFS

 ● FFS:

     ● Possible minimum timing of n + 2 TTI

         ● FFS max TA in this case

         ● FFS what other restrictions (if any) on when reduced processing times of n + 2 could be applied

     ● Possibility of scheduling by EPDCCH.

Agreement:

 ● Reduced processing time (s) are RRC configured for the UE

 ● Working assumption: A mechanism for dynamic fallback to legacy processing timings (n + 4) is supported

- Details FFS

Working assumption can be revised if it is not found to be feasible

In the 3GPP RAN1 # 85 meeting related to the DL-RS, the following matters were decided.

Agreement:

 ● For sPDSCH based on a CRS based transmission scheme the maximum number of supported layers is 4

 ● For sPDSCH based on a DM-RS based transmission scheme,

- the maximum number of supported layers is 2

- the maximum number of supported layers is 4

- the maximum number of supported layers is 8

 ● FFS for PDSCH based on a DM-RS based transmission scheme it is recommended to increase PRB bundling size compared to PDSCH for at least sTTI lengths shorter than 1-slot

As described above, the study on the physical layer for the short TTI is ongoing, and a detailed discussion on the control channel design is underway. Specifically, there is no specific terminal operation for transmission and detection for detection of sPDCCH and legacy PDCCH.

In the present invention, a specific procedure for acquiring a short DCI of a terminal considering a valid period of a DCI transmitted through a legacy PDCCH is presented.

Basically, for PDCCH detection, blind decoding is performed based on a given hashing function based on the following aggregation level, PDCCH candidate.

The search space definition and blind decoding procedure using the hashing function given below are as follows.

One) Search space definition

◆ Search Space (Cont'd)

● The variable Y _k

       √ For the COMMON search space

       √ For the UE-specific search space

◆ Size of search space

    ● CCE units

    ● The size depends on the type and the aggregation level of the search space

    ● 4 kinds of size: 6, 8, 12, 16 [CCEs]

Number of PDCCH candidates M ^(L)

    ● The set of PDCCH candidates are defined in terms of search spaces

● Mainly connected to the aggregation level

2) Relationship between Y _k and search space

■ Offset of starting-point of search space

■ Offset ( Y _k ) has UE-specific value within UE-specific search space

■ Offset ( Y _k ) is fixed by zero in common search space

Example: Common Search Space

√ Aggregation level ( L ): 4, N _CCE = 35

    √ Size of Search space: 16 CCEs

√ Number of candidates ( M ^(L) ): 4

√ Y _k = 0 ( Y _k does not get affected by n _RNTI )

Example: UE -specific Search Space

√ Aggregation level ( L ): 4, N _CCE = 35

    √ Size of Search space: 8 CCEs

√ Number of candidates ( M ^(L) ): 2

Finally, based on the defined search space, the terminal determines the maximum number of blind decoding as follows to find its PDCC. That is, for the aggregation levels 1, 2, 4, and 8, the PDCCH candidates are UESS = 16 and CSS = 6. Therefore, since there are two PDCCH formats to be found in each transmission mode, DCI format 1A + α ', the total number of blind decoding is 44 (based on Legacy PDCCH).

In this proposal, the concrete operation of the sTTI service terminal according to the coverage of the DCI obtained from the legacy PDCCH is presented by the sTTI terminal.

Solution 1. sTTI  Legacy of terminal PDCCH First received  It is only valid within one legacy subframe (= 1 ms).

In this proposal, we propose a concrete method of setting the effective period of the slow DCI. That is, when the sTTI is configured in the legacy subframe, only the slow DCI received through the in-subframe legacy PDCCH is valid. That is, the UE receives the sTTI service-related scheduling or control information through the legacy PDCCH every subframe.

As a result, the sTTI service is performed within the existing 1ms-based dynamic scheduling frame through the corresponding method.

The sTTI has a different sTTI length, number, etc., which are configured within 1 ms depending on its configuration. For example, DL sTTI has only 2-symbol / 7-symbol. Since the 7-symbol sTTI has 2 sTTIs in 1 ms, the UE can effectively use the legacy PDCCH only for scheduling of 2 sTTIs. If '2-symbol sTTI', 7 sTTI is assumed to be configured at 1 ms, and DCI obtained through legacy PDCCH can be commonly used for 7 sTTI.

Solution 2. sTTI  Legacy of terminal PDCCH After first receiving  ' N _X 'Subframe  It is available for a while.

Solution 2-1. Legacy PDCCH  The validity period is Layer With signaling To the terminal  send.

In this proposal, we propose a concrete method of setting the effective period of slow DCI to 1 subframe or more. That is, when the sTTI is configured, the slow DCI obtained through the legacy PDCCH is valid for multiple subframes (> 1 subframe). That is, the UE updates the slow DCI in a predetermined period.

At this time, the BS may set the following information for receiving the Legacy PDCCH to the MS as higher signaling.

- Transmission position of Legacy PDCCH capable of receiving slow DCI

- Slow DCI transmission cycle / update cycle

Specifically, the effective range of the slow DCI, the transmission period, and the location information may be described in the RRC message.

Method 3. The base station periodically sTTI  Including triggering information DCI  And transmits it to the corresponding legacy PDCCH  Only the detected terminal sTTI  Service can be performed.

In this proposal, a concrete method of sending information about slow DCI transmission is presented.

That is, configuration information on how long to transmit the slow DCI acquired by the UE. This is directly related to setting the PDCCH monitoring parameter for sTTI transmission in other words. The UE periodically monitors the slow DCI transmitted in the legacy PDCCH, and the corresponding configuration information can be transmitted to the sTTI UE through upper layer signaling.

For example, upper layer signaling can be configured as an RRC message and can be defined as sPDCCH-config or sTTI-config.

For example, the setting information for the transmission period of the slow DCI can be defined as follows.

- Slow DCI transmission period

- Slow DCI transmission subframe

- Slow DCI transmission sub-frame offset etc.

The transmission position of the Legacy PDCCH can be transmitted by setting a value of offset based on a specific subframe. For example, if 'start position information = 0' and 'offset = 3', the UE performs a legacy PDCCH detection operation to obtain a slow DCI in a fourth subframe.

The update period refers to the effective time or period of the slow DCI. For example, if the slow DCI update period of the UE is set to 10 ms even if the slow DCI is transmitted in 5 ms units, the UE detects the legacy PDCCH in 10 ms units and acquires the slow DCI.

In the present invention, a specific operation for DCI / sDCI detection for a short TTI terminal can be defined by setting the valid period of the DCI transmitted through the legacy PDCCH in the 3GPP LTE / LTE-A system.

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

Referring to FIG. 8, a base station 1000 according to another embodiment includes a control unit 1010, a transmission unit 1020, and a reception unit 1030.

The controller 1010 controls the overall operation of the base station 1000 according to the setting of the effective period of the slow DCI in the short TTI frame structure according to the present invention described above.

The transmitting unit 1020 and the receiving unit 1030 are used to transmit and receive signals, messages, and data necessary for carrying out the present invention to and from the terminal.

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

9, a user terminal 1100 according to another embodiment of the present invention 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 controls the overall operation of the user terminal 1100 according to the setting of the effective period of the slow DCI in the short TTI frame structure according to the present invention described above.

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.

Appendix

[One] Ericsson, Huawei, "New SI proposal Study on Latency reduction techniques for LTE ", RP-150465, Shanghai, China, March 9-12, 2015.

[2] R2-155008, "TR 36.881 v0.4.0 on Study Latency reduction techniques for LTE ", Ericsson (Rapporteur)

[3] R1-160927, "TR 36.881-v0.5.0 on Study Latency reduction techniques for LTE ", Ericsson (Rapporteur)

[4] 3GPP TS 36.331 v13.0.0 R1-160927, "Radio Resource Control (RRC)"

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)

A method for setting a slow DCI in a short TTI frame structure,
receiving a slow DCI having a validity period set via a legacy PDCCH;
Performing a short TTI service based on the slow DCI only in a subframe in which the slow DCI is first received if the effective period of the slow DCI is one subframe; And
And performing the short TTI service based on the effective range of the slow DCI received through the RRC message when the effective period of the slow DCI is a plurality of subframes.

Images