KR20180125118A - Apparatus and method of adaptive CRC attachment in new radio - Google Patents

Abstract

The present invention relates to a CRC attachment method for a new/5G radio access network (new radio, NR), and more particularly, to a CRC attachment method when data of an eMBB terminal is transmitted or retransmitted through a URLLC data channel. The method comprises: allocating resources for eMBB data; allocating some of the allocated resources as resources for URLLC data; and setting the length of CRC for the eMBB data to be the same as the length of CRC for the URLLC data.

Description

[0001] Apparatus and method for adaptive CRC attachment in new radio network [

The present embodiments relate to a CRC attachment method for a next generation / 5G radio access network (hereinafter referred to as " NR [New Radio] ").

One embodiment of the present invention relates to a method of configuring an adaptive CRC in a next generation wireless network, the method comprising: allocating resources for eMBB data; pre-empting a part of resources allocated for eMBB data and allocating resources for URLLC data And setting a CRC for eMBB data and a CRC for URLLC data to the same length.

FIG. 1 shows an example of symbol level alignment among different SCS.
Figure 2 shows the concept of LTE BRP Tx. Architecture (refer to TS 36.212).
Figure 3 shows an example of eMBB and URLLC multiplexing.
Figure 4 shows an example of a generic CRC attach configuration.
Figure 5 shows an example of CBG / CB partitioning of TB.
6 shows an example of eMBB / URLLC data channel segmentation transmission of CBGs using the same CRC.
FIG. 7 shows an example of eMBB / URLLC data channel segmentation transmission of CBGs using different CRCs.
Fig. 8 shows an example of the CRC setting of the CBs in the CBG according to the method 2-1.
9 shows an example of the CRC setting of the CBs in the CBG according to Method 2-2.
10 shows an example of the CRC setting of the CBs in the CBG according to the method 2-3.
11 shows an example of the CRC setting of the retransmission CBG according to measure 3. Fig.
FIG. 12 is a diagram illustrating a configuration of a base station according to another embodiment.
13 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 the present 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, the PDCCH, which is an embodiment of the present invention, may be applied to the PDCCH, and the PDCCH may be applied to the portion described with the EPDCCH.

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.

[5G NR (New Rat)]

3GPP recently approved the study item "Study on New Radio Access Technology" for research on next generation / 5G radio access technology, and based on this, RAN WG1 has frame structure, channel coding and modulation , waveform & multiple access scheme and so on. NR is required not only to improve data transmission rate as compared with LTE, but also to design various QoS requirements that are required according to granular and specific usage scenarios. In particular, enhancement mobile broadband (eMBB), massive MTC (MMTC) and URLLC (Ultra Reliable and Low Latency Communications) are defined as typical usage scenarios of NR. structure design is required. Since each usage scenario has different requirements for data rates, latency, reliability, coverage, etc., it is a method to efficiently satisfy the requirements of each usage scenario through frequency bands constituting an NR system. there is a need for an efficient multiplexing of radio resource units based on subcarrier spacing, subframe, TTI, etc., for example.

One method is to support TDM, FDM or TDM / FDM based multiplexing on one or more NR component carriers (s) for numerology with different subcarrier spacing values, and a scheduling unit in the time domain A discussion was made on how to support more than one time unit in composition. In this regard, NR is a type of time domain structure defined as a subframe. Reference numerology for defining the subframe duration is defined as 14 OFDM symbols of 15 kHz sub-carrier spacing (SCS) based normal CP overhead equivalent to LTE To define a single subframe duration. Thus, subframes in NR have a time duration of 1ms. However, unlike LTE, NR subframes are absolute reference time durations, and slots and mini-slots can be defined as time units that are the basis of actual uplink and downlink data scheduling. In this case, the number of OFDM symbols constituting the slot, y value is defined as y = 7 and 14 for the numerology having the SCS value of up to 60 kHz, and for the numerology having the SCS value larger than 60 kHz, y = Lt; / RTI >

Accordingly, any slot can be composed of 7 or 14 symbols, and all symbols are used for DL transmission according to the transmission direction of the corresponding slot, or all symbols are used for UL transmission, or the DL portion + (gap) + UL portion.

Also, a mini-slot composed of a smaller number of symbols than a corresponding slot is defined in an arbitrary numerology (or SCS), and a short-time time-domain scheduling interval is set for uplink / downlink data transmission or reception, A long-time time-domain scheduling interval for uplink / downlink data transmission and reception can be configured. In particular, in the case of transmission and reception of latency critical data such as URLLC, scheduling is performed in units of 0.5 ms (7 symbols) or 1 ms (14 symbols) based on a numerology-based frame structure having a small SCS value, such as 15 kHz , it is difficult to satisfy the latency requirement. Therefore, it is possible to define a mini-slot composed of a smaller number of OFDM symbols than the corresponding slot and to schedule the latency critical data such as the URLLC based on the defined mini-slot.

Alternatively, as described above, by supporting the numerology having different SCS values in one NR Carrier by multiplexing the TDM and / or FDM scheme, it is possible to reduce the number of slots based on the slot (or mini-slot) length defined for each numerology Scheduling of data according to latency requirement is also considered. For example, as shown in FIG. 1, when the SCS is 60 kHz, the symbol length is reduced to about 1/4 of that of the SCS 15 kHz. Therefore, when one slot is composed of 7 OFDM symbols, While the slot length based on 60 kHz is reduced to about 0.125 ms.

In this way, the NR is discussing how to satisfy the requirements of URLLC and eMBB by defining different SCSs or different TTI lengths.

[ NR PDSCH / PUSCH  TB, CB, CBG  Configuration]

In the case of the existing LTE system, when the data channel is allocated (PDSCH / PUSCH), the processing is performed in TB units as a whole. That is, the best gNB determines the TB size considering the channel state (CQI) of the UE.

For the next determined TB, segmentation takes place considering the maximum input size of the encoder. In case of LTE, the maximum input size for the data channel is configured as shown in FIG. 2 at 6144 bits. Therefore, TB is divided into several CBs considering this CB size.

Number of Input bits or the size of transport blockA:

Number of Input bits or the size of the transport block

)B: The size of the entire transport block (

)

L: CRC length (e.g., in DL-SCH, CRC-length is 24)

)Z: The maximum code block size (

)

In addition, retransmission also causes all of the CBs to retransmit the entire TB if a nack occurs. However, at present, NR is currently under discussion as follows.

At the 3GPP RAN1 # 88 meeting, the following matters related to the code block were determined.

Working assumption:

CBG-based transmission with single/multi-bit HARQ-ACK feedback is supported in Rel-15, which shall have the following characteristics:

CBG-based transmission with single / multi-bit HARQ-ACK feedback is supported in Rel-15, which shall have the following characteristics:

o Only allow CBG based (re) -transmission for the same TB of a HARQ process

In this case, the UE reports a single HARQ ACK bits for the TB

o CBG can include one CB

o CBG granularity is configurable

That is, the entire procedure design is considered to enable not only HARQ ack / nack transmission in TB units but also A / N transmission in a specific code block group unit. In this way, it can be predicted that, when an error occurs in some CBs of the TB, retransmission can be performed except for a portion in which no error occurs. In other words, it can be seen that efficiency can be increased by eliminating the redundancy of retransmission.

A transport block, a CB (code block) and a CBG (code block group) of the above-mentioned data channels have a separate CRC to check for data errors. The CRC attachment procedure of TB and CB in existing LTE is as follows.

Basically, in LTE, the TB size is segmented based on the maximum input size 6144 of the turbo encoder. Also, when the TB is divided into several CBs based on this, the CBs are additionally attached with CRCs. The detailed procedures and CRC types used in TB and CB are as follows.

Function

Function

  ◆ Transport-block CRC attachment

- CRC attachment to the data and control streams from MAC layer

- CRC size is fixed 24 in PDSCH

  ◆ Code-block segmentation

- If CRC-attached TBS > 6144, code-block segmentation is enabled.

- Code-block segmentation process is described in TS 36.212 subclause 5.1.2

- Code-block size should not exceed the maximum code block size, '6144'

- The size of all the segmented code-blocks depends on the block size K in TS 36.212 Table 5.1.3-3

  ◆ Code-block CRC attachment

- CRC attachment to segmented code blocks

- CRC size is fixed 24 in PDSCH

CRC type

CRC type

_{◆ Transport-block CRC: g CRC24A} (D) = [D 24 + D 23 + D 18 + D 17 + D 14 + D 11 + D 10 + D 7 + D 6 + D 5 + D 4 + D 3 + D + 1]

    → refer TS 36.212 subclause 5.1.1

◆ Code-block CRC calculation: g CRC24B (D) = [D 24 + D 23 + D 6 + D 5 + D + 1]

→ refer TS 36.212 subclause 5.1.1

The present invention proposes a CRC attachment method in the case where data of an eMBB terminal is transmitted or retransmitted through a URLLC data channel in a NR.

Basically, this proposal assumes that eMBB data is transmitted simultaneously with URLLC. For example, as shown in FIG. 3, the URLLC and the eMBB can be multiplexed on the same resource, and details thereof are currently being discussed.

In the situation where such eMBB and URLLC data are multiplexed, a concrete method of applying pre-emption to URLLC is basically under discussion. Basically, it punctures the eMBB data of the area overlapped with the URLLC data and transmits the puncturing indication information to the eMBB terminal. At this time, since the error probability increases in the PDSCH of the eMBB terminal, retransmission may occur frequently. This is because the probability of frequent inconsistency of the channel status information is increased.

- CSI estimation of eMBB terminal: feedback to gNB after deriving CSI using channel estimation reference signal such as CSI-RS

- Issue point: Data loss due to URLLC (eg puncturing loss) is not reflected in CSI derivation through reference signal like CSI-RS.

In this situation, the standardization meeting was agreed upon to provide URLLC indication information to eMBB terminals. Therefore, the eMBB terminal should receive the URLLC indication information so that it can know in a certain way whether the URLLC data is multiplexed on its own data channel. Basically the URLLC preemption method assumes puncturing.

In this proposal eMBB  Part of the data With URLLC  Assuming a situation that can be sent, The CBG (Code block group)  single Of URLLC PDSCH / PUSCH  Lt; RTI ID = 0.0 > URLLC PDSCH / PUSCH  To be transmitted through Capital  have. The same principle applies to the basic transmission and retransmission processes.

In the proposals below, a transport block (TB) can be replaced with a TB because it can consist of a single CBG or CBs.

Measure 1. All or part of the same TB CBG (code-block group) / CB ( clode -block < / RTI > are transmitted to the data channels of different service purposes The CRC  All have the same length.

In this proposal, it is assumed that TBs are divided and transmitted to different physical channels basically. For example, some CBGs are transmitted on the eMBB data channel (PDSCH / PUSCH) due to the specific configuration of data to the eMBB terminal, and the rest are transmitted on the URLLC data channel (URLLC PDSCH / PUSCH).

Generally, the CRC is added before the input of the channel encoding in order to check the integrity of the information block as shown in FIG.

In this case, the CRC attached to the existing TB is a general configuration method using a predetermined value or a generated function expression. Next, the CBG should be supplemented with additional CRCs, with an additional CRC for each CB. In this proposal, a single TB is divided into several CBGs, and even if a part of CBGs or CBs are divided into data channels for different service purposes, there is no change in CRC. For example, as shown in FIG. 5, it is assumed that the TB for the eMBB service is divided into four CBGs.

If each CBG includes four CBs in total, the entire TB is divided into CBGs / CBs as shown in FIG. Here, even if a separate CRC is defined for the URLLC data channel, the TB uses the CRC generated based on the eMBB. Therefore, as shown in FIG. 6, the CRC sets used for generating eMBB data are used as they are.

Method 2. All or part of the same TB CBG (code-block group) / CB (code-block) are transmitted to data channels of different service purposes CRC  All have different lengths.

In this proposal, unlike the above-mentioned 'scheme 1', when CBG / CBs are divided and transmitted to different transmission channels, all CRCs to be added are generated and attached.

For example, it is assumed that some CBGs are transmitted on the eMBB data channel (PDSCH / PUSCH) and the rest are transmitted on the URLLC data channel (URLLC PDSCH / PUSCH) due to the specific setting of data to the eMBB terminal as in the case of the method 1. In this case, it is a common setting method to use a predetermined value of the CRC attached to the existing TB, but it can be seen that another CRC is attached to the CBG which is divided and transmitted by the URLLC PDSCH as shown in FIG.

In other words, 'CRC type-B' is used for CBG # 1-3 transmitted to existing eMBB data channels, and a new CRC type-b is used for CBG # 4 transmitted through URLLC data channel.

Option 2 -One. Transmitted to the data channel for the purpose of another service CBG has  Changed length CRC  And CB has the same length as before CRC  Attaches.

In this proposal, in the above-mentioned measure 2, the CRC addition setting related to the hierarchy of the CBG / CB is described. In this proposal, as shown in FIG. 7, a Type-b CRC different from the existing CBGs is added to the CBG # 4 transmitted through the URLLC data channel. In this proposal, a different CRC is attached only to the CBG transmitted through the other service channel, and the existing CRC is attached to the CBs within the CBG. Therefore, as in CBG # 4 of FIG. 8, CB # 13-16 of CBG # 4 uses the same CRC as the conventional one.

Option 2 -2. Transmitted to the data channel for the purpose of another service CBG has  Of the same length as before CRC  And CB has the changed length CRC  Attaches.

In this proposal, the same CRC is attached to the CBG transmitted through the other service channel, and a different CRC is newly attached to the CBs within the CBG. Therefore, it can be seen that the CRC of CBG # 4 in FIG. 9 is the same as that of CBG # 4, and that CB # 13-16 of CBG # 4 uses CRC different from the existing CRC.

Option 2 -3. Transmitted to the data channel for the purpose of another service CBG and  CB has all the changed lengths CRC  Attaches.

In this proposal, a different CRC is newly attached to both the CBG transmitted through the other service channel and the CBs within the CBG. Therefore, it can be seen that CB # 4-16 in FIG. 10 and CB # 13-16 in CBG # 4 use different CRCs.

Solution 3. eMBB  When transmitting data, some CBG URLLC  If it is retransmitted through CBG / CBs Of URLLC  Follow the CRC add process.

In this proposal, it is assumed that a part of eMBB data is retransmitted through URLLC. Through this, it is possible to keep the delay to a minimum through immediate retransmission of eMBB data and instant retransmission to CB or CBG which can cause detection error without Ack / Nack feedback of eMBB data through setting of specific resource .

At this time, it is assumed that the URLLC data channel is basically set to resources smaller in size than the eMBB. In the URLLC, in order to improve the data detection accuracy to the maximum, an environment in which more information data is transmitted is advantageous. Therefore, it is advantageous for CRC size itself to designate a CRC for URLLC that is smaller than the existing data size for URLLC. Therefore, according to the proposal, the CB / CBGs that perform retransmission due to errors in the eMBB data follow the CRC attachment procedure defined in URLLC. That is, a CRC different from the existing CRC may be newly added to the CBG / CBs retransmitted through the URLLC data channel, or a CRC defined in the procedure transmitted through the URLLC data channel may be substituted.

FIG. 12 is a diagram illustrating a configuration of a base station according to another embodiment.

Referring to FIG. 12, 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 adaptive CRC setting method in the next generation wireless network 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.

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

13, a 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.

Also, the controller 1120 controls the overall operation of the user terminal 1100 according to the adaptive CRC setting method in the next generation wireless network 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 portions of the standard documents are added to or contained in the scope of the present invention.

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)

In an adaptive CRC setting method in a next generation wireless network,
allocating resources for eMBB data;
Assigning a part of resources allocated for the eMBB data as a resource for URLLC data; And
Setting a CRC for the eMBB data and a CRC for the URLLC data to the same length.

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