KR20120119174A - Apparatus and method for transmitting control information - Google Patents

Abstract

PURPOSE: An apparatus and method for transmitting control information are provided to reduce an error detection probability of control information by using a part of a control information field for error detection. CONSTITUTION: A resource block restricts a pattern allocated to a terminal in a resource allocation control part(1155). The resource allocation control part generates a resource restriction indicator indicating the restriction of the pattern. A down link control information generating part(1160) generates control information including a field consisting of a first bit region and a second bit region directing resources which are allocated to the terminal. The down link control information generating part adds a CRC(Cyclic Redundancy Check) parity bit to the control information. The down link control information generating unit outputs scrambled control information. A transmission part(1165) transmits PDCCH(Physical Downlink Control Channel) or the resource restriction indicator to the terminal by mapping the scrambled control information with a PDCCH. [Reference numerals] (1105) Receiving part; (1110) Decoding part; (1115) Error detection part; (1120) Transmission part; (1155) Resource allocation control part; (1160) DCI generating part; (1165) Transmission part; (1170) Receiving part; (AA) Resource restriction indicator; (BB) PDCCH, data; (CC) Data

Description

Apparatus and method for transmitting control information {APPARATUS AND METHOD FOR TRANSMITTING CONTROL INFORMATION}

The present invention relates to communication, and more particularly, to an apparatus and method for transmitting control information, and an apparatus and method for receiving.

The base station schedules radio resources to efficiently use the limited radio resources. If there is no data packet transmitted to a radio resource allocated to a user, the base station schedules the radio resource that is not in use so that other users can use it, thereby increasing the efficiency of the radio resource. In this way, the radio resources are allocated to a user who does not have a data packet to transmit and receive, but a radio resource is allocated to a user who has a data packet to transmit and receive, but the radio resources are dynamically allocated at regular intervals in frequency or time. This is called dynamic scheduling.

However, in the case of a service such as Voice over Internet Protocol (VoIP), the base station continuously allocates the radio resources allocated to the terminal for a predetermined time without changing the radio resources. This resource allocation method is semi-persistent scheduling (SPS). It is called). According to the radial scheduling, the base station transmits control information indicating that the radial scheduling is activated to the terminal. The terminal may know that the radial scheduling is activated from the control information, and may communicate with the base station based on the radial scheduling. For example, if the ringless scheduling is applied to the terminal, the terminal may transmit or receive data using the previously allocated radio resource even if there is no control information for resource allocation.

If the terminal fails to receive the control information indicating that the ring scheduling is activated, the terminal cannot operate according to the ring scheduling, and can not successfully recover a signal carried on the radio resource allocated continuously. This can lead to serial performance degradation.

An object of the present invention is to provide an apparatus and method for transmitting control information which is robust against errors.

Another technical problem of the present invention is to provide an apparatus and method for receiving error-resistant control information.

Another technical problem of the present invention is to provide an apparatus and method for lowering the error probability of downlink control information (DCI).

Another technical problem of the present invention is to provide an apparatus and method for setting a specific bit of an information field for resource allocation in a DCI to a specific value.

Another technical problem of the present invention is to provide an apparatus and method for transmitting information indicating that resource allocation is limited.

Another technical problem of the present invention is to provide an apparatus and method for generating a DCI indicating activation or release of a ring scheduling.

According to one aspect of the present invention, there is provided an apparatus for transmitting control information. The transmission apparatus may include: a resource allocation control unit configured to limit a pattern to which a resource block is allocated to a terminal, to generate a resource limit indicator indicating the limitation of the pattern, and to indicate a resource allocated to the terminal. Generate control information including a first bit area and a field consisting of a second bit area whose number of bits varies according to the degree to which the pattern is defined, and cyclic redundancy check (CRC) parity in the control information A downlink control information generation unit for adding a parity bit and scrambling a specific radio network temporary identifier (RNTI) to the added CRC parity bit to output scrambled control information; and And a transmitter configured to map the scrambled control information to a PDCCH and transmit the PDCCH or the resource limit indicator to the terminal.

According to another aspect of the present invention, a method of transmitting control information is provided. The transmission method may include: defining a pattern in which a resource block is allocated to a terminal; transmitting a resource limit indicator indicating the limitation of the pattern to the terminal; a first bit area indicating a resource allocated to the terminal; Generating control information including a field consisting of a second bit area whose number of bits varies according to a degree to which the pattern is limited, adding a CRC parity bit to the control information, and adding the CRC parity bit to the added CRC parity bit Scrambling a specific RNTI, and mapping the scrambled control information to a PDCCH and transmitting the same to the terminal.

In services such as ring scheduling, which does not require instantaneous resource allocation and does not require large bandwidths, some of the remaining control information fields for error detection are limited to error detection by limiting resource allocation to the extent that performance is not degraded. Can be used. This can lower the probability of error detection of the control information. False detection probability means the probability of misrecognizing other users' control information as their own.

1 shows a wireless communication system to which the present invention is applied.
2 shows a structure of a radio frame to which the present invention is applied.
3 is an exemplary diagram showing a resource grid for one downlink slot to which the present invention is applied.
4 is an example of a resource allocation method to which the present invention is applied.
5 is another example of a resource allocation method to which the present invention is applied.
6 is another example of a resource allocation method to which the present invention is applied.
7 is a flowchart illustrating a method of transmitting control information according to an embodiment of the present invention.
8 is an exemplary diagram illustrating a second bit area of a resource allocation field according to the present invention.
9 is a flowchart illustrating a method of transmitting control information by a base station according to an embodiment of the present invention.
10 is a flowchart illustrating a method of receiving control information by a terminal according to an embodiment of the present invention.
11 is a block diagram illustrating a base station transmitting control information and a terminal receiving control information according to an embodiment of the present invention.

Hereinafter, some embodiments will be described in detail with reference to 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 the following description of the embodiments 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 disclosure rather unclear.

In addition, the embodiments proposed herein may be applied to a wired communication network as well as a wireless communication network. Work performed in the communication network may be performed in the process of controlling the network and transmitting data in a system (for example, a base station) that manages the communication network, or may be performed in a terminal coupled to the communication network.

1 shows a wireless communication system to which the present invention is applied.

Referring to FIG. 1, a wireless communication system 10 is widely deployed to provide various communication services such as voice, packet data, and the like. The wireless communication system 10 includes at least one base station 11 (BS). Each base station 11 provides a communication service for a particular geographic area or frequency area (generally called a cell) 15a, 15b, 15c. The cell may again be divided into multiple regions (referred to as sectors).

A mobile station (MS) 12 may be fixed or mobile and may be a user equipment (UE), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, (personal digital assistant), a wireless modem, a handheld device, and the like. The base station 11 generally refers to a fixed station communicating with the terminal 12, and includes an evolved-NodeB (eNB), a base transceiver system (BTS), an access point, and a femto eNB. ), Home eNB (HeNB), relay, etc. may be called other terms. The cell should be interpreted in a generic sense to indicate a partial area covered by the base station 11 and is meant to cover various coverage areas such as a megacell, a macro cell, a microcell, a picocell, and a femtocell.

Hereinafter, downlink refers to a communication or communication path from the base station 11 to the terminal 12, and uplink refers to a communication or communication path from the terminal 12 to the base station 11. . In the downlink, the transmitter may be part of the base station 11, and the receiver may be part of the terminal 12. In the uplink, the transmitter may be part of the terminal 12, and the receiver may be part of the base station 11. There is no limitation on the multiple access scheme applied to the wireless communication system 10. (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier-FDMA , OFDM-CDMA, and the like. The uplink transmission and the downlink transmission may use a time division duplex (TDD) scheme transmitted using different times or a frequency division duplex (FDD) scheme transmitted using different frequencies.

2 shows a structure of a radio frame to which the present invention is applied.

Referring to FIG. 2, a radio frame includes 10 subframes, and one subframe includes two slots. The time taken for one subframe to be transmitted is called a transmission time interval (TTI). For example, one subframe may have a length of 1 ms, and one slot may have a length of 0.5 ms.

One slot includes a plurality of orthogonal frequency division multiplexing (OFDM) symbols in the time domain and includes a plurality of resource blocks (RBs) in the frequency domain. The OFDM symbol is for representing one symbol period, and may be referred to as an SC-FDMA symbol or a symbol period according to a multiple access scheme. The RB includes a plurality of consecutive subcarriers in one slot in a resource allocation unit.

The structure of the radio frame is only an example, and the number of subframes included in the radio frame or the number of slots included in the subframe and the number of OFDM symbols included in the slot may be variously changed.

The preceding two or three OFDM symbols of the first slot in the subframe are control regions to which a Physical Downlink Control Channel (PDCCH) is allocated, and the remaining OFDM symbols are allocated to a Physical Downlink Shared Channel (PDSCH). Data area.

The downlink control channel includes a physical control format indicator channel (PCFICH), a PDCCH, a physical hybrid-ARQ indicator channel (PHICH), and the like. The PCFICH is transmitted in the first OFDM symbol of a subframe and carries information about the number of OFDM symbols (ie, the size of the control region) used for transmission of the PDCCH in the subframe. The PHICH carries an ACK (Acknowledgement) / NACK (Not-Acknowledgement) signal for an uplink HARQ (Hybrid Automatic Repeat Request). That is, the ACK / NACK signal for the uplink data transmitted by the UE is transmitted on the PHICH.

3 is an exemplary diagram showing a resource grid for one downlink slot to which the present invention is applied.

Referring to FIG. 3, each element on the resource grid is called a resource element (RE), and one resource block includes 12 × 7 resource elements. The number N _DL of resource blocks included in the downlink slot depends on the downlink transmission bandwidth set in the cell. The bandwidths considered in LTE are 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, and 20 MHz, which are 6, 15, 25, 50, 75, and 100, respectively. At least one resource block corresponding to each band may be bundled to form a resource block group (RBG). For example, two adjacent resource blocks may constitute one resource block group.

In LTE, the total number of resource blocks for each bandwidth and the number of resource blocks constituting one resource block group are shown in Table 1.

Bandwidth Total number of resource blocks The number of resource blocks belonging to one resource block group Total number of resource block groups 1.4 MHz 6 One 6 3 MHz 15 2 8 5 MHz 25 2 13 10 MHz 50 3 17 15 MHz 75 4 19 20 MHz 100 4 25

Referring to Table 1, the total number of available resource blocks varies according to a given bandwidth. The difference in the total number of resource blocks means that the size of information indicating resource allocation is different. In addition, the number of cases in which resource blocks are allocated may vary depending on the resource allocation method. As an example of a resource allocation scheme, a resource block may be allocated using a bitmap format (type 0). As another example of the resource allocation scheme, resource blocks may be allocated at predetermined intervals or periods (type 1). As another example of a resource allocation scheme, resource blocks may be allocated as contiguous constant length regions (type 2). The resource block allocated to the terminal is indicated by the resource allocation field, and the bit request amount of the resource allocation field varies according to each type of resource allocation scheme and the total number of resource blocks for each bandwidth.

4 is an example of a resource allocation method to which the present invention is applied. This is type 0 resource allocation.

Referring to FIG. 4, the type 0 resource allocation method is a method of allocating the entire resource blocks of the system to the UE in units of clusters grouped into at least one consecutive resource block. At least one resource block is spaced between clusters. This is also known as non-contiguous resource allocation. If there is only one cluster, this is called Contiguous Resource Allocation, and Type 0 includes this case. Downlink type 2 is considered a case of indicating only continuous resource allocation.

In FIG. 4, a total of four clusters are allocated to the terminal. The first cluster includes one resource block, the second cluster includes three resource blocks, the third cluster includes two resource blocks, and the fourth cluster includes one resource block. Depending on how many clusters you allocate, your system's throughput will vary.

Type 0, type 1, and type 2 correspond to downlink resource allocation, and different configurations may be made for uplink resource allocation. Uplink resource allocation may be classified into type 0 and type 1 for uplink.

The uplink type 0 may use the same method as the downlink type 2. The uplink type 1 is a case of using a limited cluster in a manner of applying an enumerated source encoding scheme, and an example of using only two clusters may be an example. Limited discontinuous resource allocation using enumerated source coding is described further below.

On the other hand, in the downlink, the type 0 allocation scheme can represent the maximum possible clusters in a given bitmap representation, but in limited discontinuous resource allocation, the number of clusters smaller or equal to the maximum clusters in the bitmap format is considered.

)이 된다. 여기서, ceiling(x)는 x보다 크거나 같은 최소 정수를 의미한다. The allocation or unassignment of each resource block may be represented by a bitmap. Each bit is mapped to each resource block. For example, if the bit is 0, the corresponding resource block is allocated to the terminal. If the bit is 1, the corresponding resource block is not allocated to the terminal. For example, FIG. 4 illustrates a case where the bitmap is 010011100110100. In the case of indicating resource allocation for a terminal in a bitmap format as in type 0, the required amount of bits is required for the number of resource blocks. In other words, the required amount of bits is, when the number of resource blocks is n, ceiling (

) Here, ceiling (x) means the minimum integer greater than or equal to x.

5 is another example of a resource allocation method to which the present invention is applied. This is a type 1 resource allocation method.

)+ceiling(log2(P))-1이다. 여기서, ceiling(log2(P))는 주기 P를 가지는 자원블록 서브셋(subset)의 크기이고, 1은 오프셋(offset)이다. 이로써 특정한 경우의 자원할당을 나타낼 수 있다. 일반적으로 타입 0와 타입 1이 같이 사용될 경우, 타입 0와 타입 1을 구분하기 위한 구분비트(differentiation bit)가 추가될 수 있다.Referring to FIG. 5, resource blocks are allocated in a periodic form, and resource allocation may be expressed in a form having a period of P and distributed at regular intervals for all resource blocks. For example, FIG. 5 is a case where the period P = 2. The number of bits needed to represent type 1 resource allocation is ceiling (

) + ceiling (log2 (P))-1. Here, ceiling (log2 (P)) is the size of the resource block subset having a period P, and 1 is an offset. This can represent resource allocation in specific cases. In general, when type 0 and type 1 are used together, a division bit for distinguishing type 0 and type 1 may be added.

6 is another example of a resource allocation method to which the present invention is applied. This is a type 2 resource allocation method.

Referring to FIG. 6, the base station may allocate a cluster consisting of at least one consecutive resource block to the terminal. One cluster is represented by an offset and a length at the start of all RBs. For example, the cluster of FIG. 6 includes two resource blocks consecutive from the third resource block since the offset is 2 and the length is 2. Type 2 represents Contiguous Resource Allocation, whereas Type 0 and Type 1 represent Non-contiguous Resource Allocation. Therefore, when the number of resource blocks is large, the number of bits of the resource allocation field required for representing the resource allocation of type 2 is smaller than that of type 0 or type 1. When n resource blocks are allocated by Type 2, the number of cases of all resource allocation is determined by Equation 1.

Therefore, the number of bits of the required resource allocation field is determined by equation (2).

As such, a bit is required to distinguish whether the resource allocation applied to the system is a discontinuous resource allocation or a continuous resource allocation. The surplus bits remaining in DCI format 0 may be used as separator bits. The surplus bits are due to DCI format 0 having the same PDCCH size as DCI format 1A. DCI format 0 and DCI format 1A are designed to have the same size, and considering the use of the internal fields of DCI format 0 and DCI format 1A respectively, DCI format 1A requires more than one bit more than DCI format 0. In DCI format 0, there are always more than one bit of surplus bits left. In the blind decoding process, DCI format 0 and DCI format 1A are treated as the same decoding process, and are blindly decoded assuming a certain size for each band. The DCI format 0 or DCI format 1A is distinguished through a division bit (a division bit for distinguishing DCI format 1A and DCI format 1A) in the PDCCH after a certain size is confirmed.

Hereinafter, the PDCCH and downlink control information to which the present invention is applied will be described. PDCCH includes resource allocation and transmission format of downlink shared channel (DL-SCH), resource allocation information of uplink shared channel (UL-SCH), resource allocation of upper layer control message such as random access response transmitted on PDSCH, It may carry a set of transmit power control commands for individual UEs in a UE group, activation / release of semi-persistent scheduling (SPS), and the like. A plurality of PDCCHs can be transmitted in the control domain, and the UE can monitor a plurality of PDCCHs. The PDCCH is transmitted on an aggregation of one or several consecutive control channel elements (CCEs). CCE is a logical allocation unit used to provide a PDCCH with a coding rate according to a state of a radio channel. The CCE corresponds to a plurality of resource element groups. The format of the PDCCH and the number of bits of the possible PDCCH are determined according to the relationship between the number of CCEs and the coding rate provided by the CCEs.

The control information of the physical layer mapped to the PDCCH is referred to as downlink control information (DCI). That is, DCI is transmitted on the PDCCH. DCI has different uses according to its format, and fields defined in DCI are also different. Table 2 shows DCI according to DCI format.

DCI Format Description 0 used for the scheduling of PUSCH (Uplink grant) in one uplink cell One used for the scheduling of one PDSCH codeword in one cell 1A used for the compact scheduling of one PDSCH codeword in one cell and random access procedure initiated by a PDCCH order 1B used for the compact scheduling of one PDSCH codeword in one cell with precoding information 1C used for very compact scheduling of one PDSCH codeword and notifying MCCH change 1D used for the compact scheduling of one PDSCH codeword in one cell with precoding and power offset information 2 used for scheduling PDSCH to UEs configured in spatial multiplexing mode 2A used for scheduling PDSCH to UEs configured in large delay CDD mode 3 used for the transmission of TPC commands for PUCCH and PUSCH with 2-bit power adjustments 3A used for the transmission of TPC commands for PUCCH and PUSCH with single bit power adjustments 4 used for the scheduling of PUSCH in one UL cell with multi-antenna port transmission mode,

Referring to Table 2, DCI format 0 indicates uplink resource allocation information, DCI formats 1 to 2 indicate downlink resource allocation information, and DCI formats 3 and 3A indicate uplink TPC (transmit) for arbitrary UE groups. power control) command. Each field of the DCI is sequentially mapped to _n information bits a ₀ through a _{n -1} . For example, if DCI is mapped to information bits of a total of 44 bits in length, each DCI field is sequentially mapped to a ₀ to a _{n −1} . DCI formats 0, 1A, 3, and 3A may all have the same payload size.

DCI includes uplink resource allocation information and downlink resource allocation information. The uplink resource allocation information may be referred to as an uplink grant, and the downlink resource allocation information may be referred to as a downlink grant.

Table 3 shows DCI of format 0 which is uplink resource allocation information (or uplink grant).

Referring to Table 3, a flag is an indicator for distinguishing DCI 0 from DCI 1A as 1-bit information. The hopping flag is 1-bit information and indicates whether frequency hopping is applied or not when the terminal performs uplink transmission. For example, if the hopping flag is 1, frequency hopping is applied during uplink transmission, and if hopping flag is 0, frequency hopping is not applied during uplink transmission.

7 is a flowchart illustrating a method of transmitting control information robust to an error according to an embodiment of the present invention.

Referring to FIG. 7, the base station sets a restriction on resource allocation (S700). Restriction of resource allocation may mean limiting a pattern of resource blocks allocated to the terminal. Alternatively, limiting resource allocation may mean reducing the degree of freedom to which resource blocks are allocated. Alternatively, limiting resource allocation may mean reducing the number of resource blocks allocated to the terminal. Alternatively, limiting resource allocation may mean increasing the number of resource blocks included in the resource block group. Restriction of resource allocation may be set in a communication environment in which a large number of terminals exist while mainly requiring less resources (or bandwidth), such as a voice call. In this case, the cluster length does not have to be large in consecutive resource allocation.

As an example, in a resource allocation such as type 2, the base station may set the maximum length of the cluster not to exceed k. Where k ≦ N _RB . N _RB is the maximum number of resource blocks allocable to the terminal according to the system bandwidth. Alternatively, the base station may set the maximum length of the cluster not to exceed N _RB / 2. DCI supported with continuous resource allocation may be Format 0 or Format 1A.

According to the continuous resource allocation, a cluster consisting of at least one resource block is allocated to the terminal. One cluster may be represented by an offset and a length, and the offset and the length may have a variable value. The number of all cases of clusters that can be represented by various offsets and lengths can be obtained by Equation 1 above.

For example, in case of allocating 100 resource blocks to the terminal by continuous resource allocation, the number of all cases of the cluster that can be represented becomes 5050 according to Equation 1. However, if the base station limits the cluster length to 1, each of the 100 resource blocks becomes one cluster. At this time, each cluster may be specified by the size of the offset. That is, the number of all cases of the cluster that can be represented is 100. If an index is assigned to each cluster, the index has a value from 0 to 99. 100 indexes may be represented by 7 bits. If the base station limits the length of the cluster to 2, the number of all cases of the cluster that can be represented is 199, which is 0 to 198. These indices can be represented by 8 bits.

As another example, in a resource allocation such as type 0, the base station may limit the maximum number of clusters not to exceed m. For example, when 100 resource blocks are allocated in units of 25 resource block groups (RBGs) in a 20 MHz band, a 25-bit resource allocation field is required. At this time, up to 13 clusters may be allocated. If the maximum number of assignable clusters is reduced to six, the number of bits required is 23 in total as shown in Equation 3 below.

Here, a discontinuous resource allocation algorithm using uplink enumerated source coding may be applied to express resource allocation by type 0.

The base station transmits a resource restriction indicator (RRI) for setting the resource allocation to the terminal (S705). The resource limit indicator may be a physical layer signal or a medium access control (MAC) message or a radio resource control (RRC) message transmitted on the PDCCH. The resource limit indicator may indicate the maximum length of the cluster. Alternatively, the resource limit indicator may simply be information indicating that the length of the cluster is limited or not limited. In this case, the terminal may recognize that the maximum length of the cluster is limited to a predetermined length or less according to a predefined restriction configuration. Alternatively, the resource limit indicator may be information indicating that the number of resource blocks or the number of resource block groups is limited. Alternatively, the resource limit indicator may be information indicating that the maximum number of clusters is limited.

If the length of the cluster is basically limited to a predetermined length by the communication protocol, the procedure of steps S700 and S705 may be omitted.

The base station divides the resource allocation field into a first bit region and a second bit region, sets the first bit region to an index value of a specific resource allocation, and sets the second bit region of the resource allocation field to a specific value irrelevant to resource allocation. Set to (S710). While the first bit region represents resource allocation, the second bit region does not represent resource allocation and is used for a purpose different from resource allocation. For example, the second bit region may lower the false detection probability of the PDCCH like the cyclic redundancy check (CRC) parity bit. In this aspect, the second bit region may be called a virtual CRC.

The number of bits in the second bit area may vary depending on the degree of limitation of resource allocation.

For example, in the resource allocation of type 0, if the cluster length is limited to 2, as described above, the index is 199 in total and can be represented by 8 bits. If the resource allocation field is 8 bits or more, the base station sets 8 bits, which is the least significant bit, as the first bit area, and divides the most significant bit (MSB) bit area exceeding the 8 bits into the second bit area. Can be. If the resource allocation field is 13 bits, 8 bits are the first bit area and the remaining 5 bits are the second bit area. Of course, the first bit region may include the MSB and the second bit region may include the LSB.

The first bit region and the second bit region may occupy a predetermined bit permutation. For example, the information bits of the resource allocation field are a ₀ , a ₁ , ..., a ₁₂ . Where a ₀ is MSB and a ₁₂ is LSB. The first bit area may be a ₅ , a ₆ ,..., A ₁₂ , and the second bit area may be a ₀ , a ₁ , ..., a ₄ . Or according to permutation, the first bit region is a ₁ , a ₃ , a ₅ , a ₇ , a ₉ , a ₁₀ , a ₁₁ , a ₁₂ , and the second bit region is a ₀ , a ₂ , a ₄ , a ₆ , a can be ₈ .

All bits of the second bit area may be predefined or fixed to the same value, for example, 0 or 1. For example, when the second bit area is 5 bits, the second bit area may be preconfigured as '00000' or '11111'. Alternatively, the second bit area may be preset to a specific value, for example, '10101'. The specific value preset in the second bit area may be pre-defined between the terminal and the base station. That is, when the terminal receives the resource limit indicator, it is possible to know what value the second bit area is set in advance.

The base station attaches the CRC parity bit obtained from the DCI including the resource allocation field divided into the first bit region and the second bit region to the DCI (S715). The CRC parity bit is calculated by substituting the information bits constituting the DCI into cyclic generator polynomials. Here, the specific value preset in the second bit area is reflected in the calculation of the CRC parity bit.

The base station adds the CRC parity bit to the DCI such that the MSB of the CRC parity bit is located after the LSB of the DCI. The addition of the CRC parity bit may be added before the MSB and may be added before the LSB or after the MSB as defined by LSB, MSB.

The base station scrambling a specific radio network temporary identifier (RNTI) to the CRC parity bit (S720), mapping the DCI to which the specific RNTI is added the scrambled CRC parity bit to the PDCCH, and the PDCCH to the terminal Transfer to (S725). Here, scrambling may be referred to as masking.

Upon receiving the PDCCH, the UE performs blind decoding on the PDCCH using a specific RNTI (S730). Here, blind decoding may be referred to as descrambling. Blind decoding defines a decoding start point in a region of a given PDCCH, performs decoding on all possible DCI formats in a given transmission mode, and decodes a user from specific RNTI information scrambled with CRC parity bits. That's the way. For example, blind decoding includes performing a XOR operation on a specific RNTI in the CRC parity bit of the DCI received by the UE.

By blind decoding, the UE acquires the DCI and the CRC parity bits, and performs error detection of the DCI based on the CRC parity bits and the second bit region (S735). For example, assume that a specific value preset in the second bit area is '00000'. However, due to the deterioration of the channel state, the value of the second bit area actually received by the terminal may be different from the preset specific value. However, since the CRC parity bit is calculated by reflecting a specific value preset in the second bit region, the terminal adjusts the value of the second bit region to '00000' regardless of the value of the second bit region actually received. In addition, error detection of DCI is performed. As a result, the second bit area is in an integrity state, and the probability of error detection of the DCI depends on whether or not an error occurs in the remaining field parts except the second bit area. That is, the probability of error detection of the DCI may be lowered by the size of the second bit region. The larger the size of the second bit region, the lower the probability of error detection of the DCI.

If there is no DCI error, the terminal interprets the meaning of the value of the first bit region according to the resource allocation type, and transmits uplink data to the base station using the resource indicated by the value of the first bit region, or downlink data Receive from the base station (S740).

In FIG. 7, an example in which the second bit region of the resource allocation field is used as a virtual CRC is illustrated, but this is only an example and a part of other fields included in the DCI may be used as the virtual CRC. For example, in setting the MCS field for determining the modulation and coding level, if the restriction is made so as not to use Quadrature Amplitude Modulation (QAM), the MSB of the MCS field may be adopted as the second bit region. At this time, the MSB of the MCS field may be set to a specific value (for example, 0) to facilitate error detection.

According to the present invention, in a service such as ring scheduling, which does not require instantaneous resource allocation and does not require a large bandwidth, control information remaining by limiting resource allocation within a limit that does not cause performance deterioration It can be used for error detection of DCI. This improves the error detection performance of the DCI and lowers the probability of error detection of the actual DCI.

According to the ring-less scheduling (hereinafter referred to as SPS), the UE may continuously use resources allocated to one PDCCH transmission without transmitting additional PDCCHs. That is, scheduling through one activation signaling continues until release signaling. The activation and release signaling of the SPS is performed in the form of PDCCH, which is arranged as follows. First, the CRC parity bit is scrambled with the SPS C-RNTI. The SPS C-RNTI is information for identifying a terminal scheduled for a certain period of time by constant control information (including resource allocation) by the SPS. Scrambling means that the XOR operation is performed between the CRC parity bit and the SPS C-RNTI. Second, the New Data Indicator (NDI) bit is set to 0 for DCI format 2 / 2A / 2B.

If blind decoding of the PDCCH for SPS activation is not successful or an error of DCI occurs, the UE cannot recognize the scheduled resources in a ring. This is because the PDCCH is not continuously transmitted. Nevertheless, if unscheduled scheduled resources are continuously allocated to the terminal, it may cause a waste of radio resources. In addition, when the error detection performance using the CRC parity bit is not sufficient, a case of misunderstanding the PDCCH for SPS activation / release of the other terminal as its own.

Therefore, it is necessary to lower the probability of error detection of the PDCCH with respect to the ring scheduling. To this end, the method for transmitting control information according to FIG. 7 may be applied to an SPS.

For example, if it is determined that the SPS can be applied to the terminal, the base station may limit resource allocation as shown in S700 and may set a DCI for activating the SPS based on S710. That is, the base station may set the DCI for activating the SPS by setting some fields of the DCI to a specific value. The DCI for activating the SPS is set differently depending on the format. This is illustrated in the following table.

DCI Field DCI format 0 DCI format 1 / 1A DCI format 2 / 2A / 2B TPC command for scheduled PUSCH set to '00' N / A N / A Cyclic shift DM RS set to '000' N / A N / A Modulation and coding scheme and redundancy version MSB is set to '0' N / A N / A HARQ process number N / A FDD: set to '000'
TDD: set to '0000' FDD: set to '000'
TDD: set to '0000' Modulation and coding scheme N / A MSB is set to '0' For the enabled transport block: MSB is set to '0' Redundancy version N / A set to '00' For the enabled transport block: set to '00' Resource block assignment set 2nd bit region to '0 ... 0' set 2nd bit region to '0 ... 0' set 2nd bit region to '0 ... 0'

Referring to Table 4, it can be seen that a value of a specific field is set to a specific value according to the DCI format. For example, in DCI format 0, the 2-bit field for the TPC command is set to '00', and the 3-bit field for the cyclic shift DM RS is set to '000', and the modulation and coding scheme and iteration version (Modulation and coding). The MSB is set to zero in a 5-bit field for scheme and redundancy version.

In addition, in the resource allocation field for resource block assignment, the second bit area is set to a constant value, for example, zero. This is illustrated in FIG. 8 as an example. Here, one example of the second bit area may be some bits (eg, five as shown in FIG. 8) of the MSB. Another example of the second bit region may be some bits of the LSB. Another example of the second bit region may be bits of a random position. As such, when the second bit area is used as a bit string for efficient error detection, the MSB part may not be set to 0 in the 5-bit field for the modulation and coding scheme and the repetitive version, and QAM modulation may be used.

When each field receives the DCI format 0/1 / 1A / 2 / 2A / 2B set as shown in Table 4 above, the UE may recognize that the received DCI is a DCI for activating the SPS. Accordingly, the terminal activates the SPS and performs error detection of the DCI using the second bit region.

Meanwhile, the DCI for releasing the SPS is also set differently depending on the format. This is illustrated in the following table.

DCI Field DCI format 0 DCI format 1A TPC command for scheduled PUSCH set to '00' N / A Cyclic shift DM RS set to '000' N / A Modulation and coding scheme and redundancy version set to '11111' N / A Resource block assignment and hopping resource allocation set to all '1's N / A HARQ process number N / A FDD: set to '000'
TDD: set to '0000' Modulation and coding scheme N / A set to '11111' Redundancy version N / A set to '00' Resource block assignment N / A set to all '1's

Referring to Table 5, it can be seen that the value of a specific field is set to a specific value according to the DCI format. For example, in DCI format 0, the 2-bit field for the TPC command is set to '00', and the 3-bit field for the cyclic shift DM RS is set to '000', and the modulation and coding scheme and iteration version (Modulation and coding). The 5-bit fields for the scheme and redundancy version are all set to one. The resource allocation fields for resource block assignment and hopping resource allocation are also set to one. That is, both the first bit area and the second bit area of the resource allocation field are set to one. The same applies to the resource block assignment of DCI format 1.

When each field receives the DCI format 0 or 1A set as shown in Table 5, the UE may recognize that the received DCI is a DCI for releasing the SPS. Accordingly, the terminal releases the activated SPS and performs error detection of the DCI using the second bit region.

9 is a flowchart illustrating a method of transmitting control information robust to an error by a base station according to an embodiment of the present invention.

9, the base station sets the limit of resource allocation (S900). Restriction of resource allocation may mean that the pattern of resource blocks allocated to the terminal is limited. Alternatively, limiting resource allocation may mean reducing the degree of freedom to which resource blocks are allocated. Alternatively, limiting resource allocation may mean reducing the number of resource blocks allocated to the terminal. Alternatively, limiting resource allocation may mean increasing the number of resource blocks included in the resource block group. Restriction of resource allocation may be set in a communication environment in which a large number of terminals exist while mainly requiring less resources (or bandwidth), such as a voice call. In this case, the cluster length does not have to be large in consecutive resource allocation.

As an example, in a resource allocation such as type 2, the base station may set the maximum length of the cluster not to exceed k.

As another example, in a resource allocation such as type 0, the base station may limit the maximum number of clusters not to exceed m. In addition, type 0 and type 1 may be limited to using only type 0. In this case, a division bit for dividing type 0 and type 1 may be used as a bit for error detection of DCI.

The base station transmits a resource limit indicator for setting the resource allocation limit to the terminal (S905). The resource limit indicator may be a physical layer signal or a MAC message or an RRC message transmitted on the PDCCH. The resource limit indicator may indicate the maximum length of the cluster. Alternatively, the resource limit indicator may simply be information indicating that the length of the cluster is limited or not limited. In this case, the terminal may recognize that the maximum length of the cluster is limited to a predetermined length or less according to a predefined limitation. Alternatively, the resource limit indicator may be information indicating that the number of resource blocks or the number of resource block groups is limited. Alternatively, the resource limit indicator may be information indicating that the maximum number of clusters is limited. If the length of the cluster is basically limited to a predetermined length by a communication protocol, the procedure of steps S900 and S905 may be omitted.

The base station divides the resource allocation field into a first bit region and a second bit region, sets the first bit region to an index value of a specific resource allocation, and sets the second bit region of the resource allocation field to a specific value irrelevant to resource allocation. Set to (S910). While the first bit region represents resource allocation, the second bit region does not represent resource allocation and is used for a purpose different from resource allocation. As an example, the first bit region may not exist. In this case, the resource allocation field may consist of only the second bit area. This may be applied to the case of DCI releasing SPS as shown in Table 5 above.

All bits of the second bit area may be predefined or fixed to the same value, for example, 0 or 1. For example, when the second bit area is 5 bits, the second bit area may be preset to '00000' or '11111'. Alternatively, the second bit area may be preset to a specific value, for example, '10101'. The specific value preset in the second bit area may be pre-defined between the terminal and the base station. That is, when the terminal receives the resource limit indicator, it is possible to know what value the second bit area is set in advance.

(1≤s_k≤N, s_k<s_{k +1})에 대해서 다음과 같은 값을 계산할 수 있다.The first bit area is set to an index value of a specific resource allocation. In the case of type 0, a limited number of clusters that are discontinuously allocated may be represented by an enumeration source coding scheme. The enumerated source encoding method has the advantage of reducing complexity and ensuring implementation stability in terms of the extension of the implemented system. M clusters arranged in ascending size at a given resource block index 1 ~ N

For (1≤s _k ≤ N, s _k <s _{k +1} ), the following values can be calculated.

이고,

는 _xC_y를 의미한다. 여기서,

의 범위를 가진다. 자원블록이 1~N까지의 인덱싱 형식(N^UL _RB는 상향링크의 자원블록의 개수)을 갖는 조건하에서 각 클러스터의 시작값은 자원블록의 인덱스값을 그대로 사용하고, 각 클러스터의 끝값은 자원블록의 인덱스값+1의 형태로 지정하여 열거원천형태로 부호화한다. here,

ego,

Means _x C _y . here,

Has a range of. Under the condition that resource blocks have an indexing form of 1 to N (N ^UL _RB is the number of uplink resource blocks), the start value of each cluster uses the index value of the resource block as it is, and the end value of each cluster is the resource block. The code is specified in the form of an index value of +1 and encoded in an enumerated source form.

The base station adds the CRC parity bit obtained from the DCI including the resource allocation field divided into the first bit region and the second bit region to the DCI (S915). The CRC parity bit is calculated by substituting the cyclically generated polynomial of the information bits constituting the DCI. Here, the specific value preset in the second bit area is reflected in the calculation of the CRC parity bit. The base station adds the CRC parity bit to the DCI such that the MSB of the CRC parity bit is located after the LSB of the DCI. In a system to which the SPS is applied, the DCI including the resource allocation field may be as shown in Table 4 or Table 5.

The base station scrambles the specific RNTI in the CRC parity bit (S920), maps the DCI added the CRC parity bit scrambled by the specific RNTI to the PDCCH, and transmits the mapped PDCCH to the terminal (S925). Here, scrambling may be called masking.

Thereafter, the base station transmits and receives data to and from the terminal using an uplink resource or a downlink resource designated by the first bit region (S930).

10 is a flowchart illustrating a method of receiving control information robust to an error by a terminal according to an embodiment of the present invention.

Referring to FIG. 10, the terminal receives a resource allocation indicator from the base station (S1000). The resource limit indicator may be a physical layer signal or a MAC message or an RRC message transmitted on the PDCCH. The resource limit indicator may indicate the maximum length of the cluster. Alternatively, the resource limit indicator may simply be information indicating that the length of the cluster is limited or not limited. In this case, the terminal may recognize that the maximum length of the cluster is limited to a predetermined length or less according to a predefined limitation. Alternatively, the resource limit indicator may be information indicating that the number of resource blocks or the number of resource block groups is limited. Alternatively, the resource limit indicator may be information indicating that the maximum number of clusters is limited. If the length of the cluster is basically limited to a predetermined length by a communication protocol, the step S1000 may be omitted.

The terminal receives the PDCCH including the DCI from the base station (S1005). The DCI may include a resource allocation field, and the resource allocation field may include a first bit area and a second bit area. In a system to which the SPS is applied, the DCI including the resource allocation field may be as shown in Table 4 or Table 5.

Upon receiving the PDCCH, the UE performs blind decoding on the PDCCH using a specific RNTI (S1010). For example, when the PDCCH is a PDCCH for activating or releasing the SPS, the UE may succeed in blind decoding by descrambling (or XORing) the SPS C-RNTI in the CRC parity bit. In this case, the terminal may acquire the DCI, and may recognize the activation or release of the SPS from the field information of the acquired DCI.

The terminal acquires the DCI and the CRC parity bits by blind decoding, and performs error detection of the DCI based on the CRC parity bits and the second bit region (S1015). For example, assume that a specific value preset in the second bit area is '00000'. However, due to the deterioration of the channel state, the value of the second bit area actually received by the terminal may be different from the preset specific value. However, since the CRC parity bit is calculated by reflecting a specific value preset in the second bit region, the terminal adjusts the value of the second bit region to '00000' regardless of the value of the second bit region actually received. In addition, error detection of DCI is performed. As a result, the second bit area is in an integrity state, and the probability of error detection of the DCI depends on whether or not an error occurs in the remaining field parts except the second bit area. That is, the probability of error detection of the DCI may be lowered by the size of the second bit region. The larger the size of the second bit region, the lower the probability of error detection of the DCI.

If there is no DCI error, the terminal interprets the meaning of the value of the first bit area according to the resource allocation type. For example, in the case of type 0, the first bit region may be encoded by an enumeration source encoding scheme. Accordingly, the terminal may perform enumeration source decoding using the following algorithm.

The terminal transmits uplink data to the base station using the resources indicated by the value of the first bit region or receives downlink data from the base station (S1020).

FIG. 11 is a block diagram illustrating a base station transmitting control information robust to errors and a terminal receiving control information robust to errors according to an embodiment of the present invention.

Referring to FIG. 11, the terminal 1100 includes a receiver 1105, a decoder 1110, an error detector 1115, and a transmitter 1120.

The receiver 1105 receives the resource limit indicator, the PDCCH or data from the base station 1150. PDCCH is a channel carrying DCI. The DCI may have various formats as shown in Table 2, and may include various information fields as shown in Table 3. In particular, the DCI includes a resource allocation field, and when the base station 1150 sets resource limitation, the resource allocation field may be divided into a first bit area and a second bit area. The first bit area indicates a resource allocated to the terminal 1100, and the second bit area is set to a specific value, for example, '0 ... 0' to increase the error detection performance of the DCI. The receiver 1105 transmits data from the base station 1150 using downlink resources indicated by the value of the first bit region.

The decoding unit 1110 performs blind decoding to search for a PDCCH for the terminal 1100. For example, the decoding unit 1110 includes performing a XOR operation on a specific RNTI to the CRC parity bit of the DCI received by the terminal 1100. Here, the specific RNTI includes the SPS C-RNTI.

The error detector 1115 obtains DCI and CRC parity bits by blind decoding on the PDCCH, and performs error detection of DCI based on the CRC parity bits and the second bit region. For example, assume that the second bit area is 5 bits and the preset specific value is '00000'. However, due to the deterioration of the channel state, the value of the second bit area actually received by the terminal 1100 may be different from a predetermined value. However, since the CRC parity bit is calculated by reflecting a specific value preset in the second bit area, the error detector 1115 may set the value of the second bit area to '00000' regardless of the value of the second bit area. After adjusting, the error detection of DCI is performed. As a result, the second bit region is in an integrity state, and the probability of detecting the DCI depends on whether or not an error occurs in the remaining field parts except the second bit region. That is, the probability of error detection of the DCI may be lowered by the size of the second bit region. The larger the size of the second bit region, the higher the probability of error detection of the DCI. In addition, even if the terminal 1100 is a PDCCH for another terminal, the probability of error detection for detecting a case in which blind decoding is succeeded by error may be increased.

If there is no DCI error, the error detector 1115 interprets the meaning of the value of the first bit area according to the resource allocation type. For example, if the resource allocation type is type 0, the error detection unit 1115 decodes the first bit area by the enumeration source decoding method as shown in Equation 4 to recognize the allocated resource.

The transmitter 1120 transmits uplink data to the base station using the resource indicated by the value of the first bit region.

The base station 1150 includes a resource allocation control unit 1155, a DCI generation unit 1160, a transmission unit 1165, and a reception unit 1170.

The resource allocation control unit 1155 defines an uplink resource or a downlink resource itself for the terminal 1100, or defines an allocated pattern. The resource allocation control unit 1155 may set a limit of resource allocation in a communication environment in which a large number of terminals exist while requiring a small resource (or bandwidth), such as a voice call.

As an example, the resource allocation controller 1155 may reduce a pattern of resource blocks allocated to the terminal 1100. For example, in a resource allocation such as type 2, the resource allocation control unit 1155 may set the maximum length of the cluster not to exceed k.

As another example, the resource allocation controller 1155 may reduce the number of resource blocks allocated to the terminal 1100. For example, in a resource allocation such as type 0, the resource allocation control unit 1155 may limit the maximum number of clusters not to exceed m.

As another example, the resource allocation control unit 1155 may reduce the degree of freedom in which the resource block is allocated. As another example, the resource allocation control unit 1155 may increase the number of resource blocks included in the resource block group.

The resource allocation control unit 1155 may generate a separate resource limit indicator when setting the resource allocation. For example, the resource limit indicator may be a physical layer signal or a MAC message or an RRC message transmitted on the PDCCH. The resource limit indicator may indicate the maximum length of the cluster. Alternatively, the resource limit indicator may simply be information indicating that the length of the cluster is limited or not limited. Alternatively, the resource limit indicator may be information indicating that the maximum number of clusters is limited.

The DCI generation unit 1160 generates a DCI for the terminal 1100. At this time, the DCI generation unit 1160 divides the resource allocation field of the DCI into a first bit region and a second bit region, sets the first bit region as an index value of a specific resource allocation, and sets the second bit of the resource allocation field. Set the zone to a specific value independent of resource allocation. Alternatively, the first bit area may not exist. In this case, the resource allocation field may consist of only the second bit area. This may be applied to the case of DCI releasing SPS as shown in Table 5 above.

The DCI generator 1160 may predefine or fix all bits of the second bit area to the same value, for example, 0 or 1. For example, when the second bit area is 5 bits, the DCI generation unit 1160 may preset the second bit area to '00000' or '11111'. Alternatively, the DCI generator 1160 may preset the second bit area to a specific value, for example, '10101'. The specific value preset in the second bit area may be pre-defined between the terminal 1100 and the base station 1150.

(1≤s_k≤N, s_k<s_{k +1})에 대해서 DCI 생성부(1160)는 다음과 같은 값을 계산할 수 있다.The DCI generation unit 1160 may set the first bit area as an index value of a specific resource allocation. In this case, when the resource allocation type is type 0, the DCI generation unit 1160 may express a limited number of clusters that are discontinuously allocated in an enumerated source encoding scheme. M clusters arranged in ascending size at a given resource block index 1 ~ N

For _{(1≤s k ≤N, s k <} s k +1) DCI generating unit 1160 can calculate the following values:

이고,

는 _xC_y를 의미한다. 여기서,

의 범위를 가진다. 자원블록이 1~N까지의 인덱싱 형식(N^UL _RB는 상향링크의 자원블록의 개수)을 갖는 조건하에서, DCI 생성부(1160)는 각 클러스터의 시작값을 자원블록의 인덱스값으로 쓰고, 각 클러스터의 끝값은 자원블록의 인덱스값+1로 씀으로써 타입0 자원할당을 표현한다. here,

ego,

Means _x C _y . here,

Has a range of. Under the condition that the resource block has an indexing format of 1 to N (N ^UL _RB is the number of uplink resource blocks), the DCI generator 1160 writes the start value of each cluster as an index value of the resource block, The end value of the cluster represents the type 0 resource allocation by writing the index value of the resource block + 1.

The DCI generation unit 1160 adds the CRC parity bit obtained from the DCI including the resource allocation field divided into the first bit region and the second bit region to the DCI. The DCI generator 1160 calculates CRC parity bits by substituting information bits constituting the DCI into a cyclically generated polynomial. Here, the DCI generation unit 1160 reflects a specific value preset in the second bit area in the calculation of the CRC parity bit. The DCI generation unit 1160 adds the CRC parity bit to the DCI such that the MSB of the CRC parity bit is located after the LSB of the DCI. In a system to which the SPS is applied, the DCI including the resource allocation field may be as shown in Table 4 or Table 5.

The DCI generation unit 1160 scrambles the specific RNTI to the CRC parity bit, and maps the DCI to which the specific RNTI is added the scrambled CRC parity bit to the PDCCH.

The transmitter 1165 transmits the PDCCH to which the DCI is mapped to the terminal 1100. In addition, the transmission unit 1165 transmits the resource limit indicator generated by the resource allocation control unit 1155 to the terminal 1100. In addition, the transmitter 1165 transmits downlink data to the terminal 1100 using a resource indicated by the value of the first bit region. The receiver 1170 receives data from the terminal 1100 using an uplink resource designated by the first bit area.

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 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 falling within the scope of the same shall be construed as falling within the scope of the present invention.

Claims (9)

In the transmission device of the control information,
A resource allocation control unit for limiting a pattern to which a resource block is allocated to the terminal and generating a resource limit indicator indicating the limitation of the pattern;
Generating control information including a first bit area indicating a resource allocated to the terminal and a field consisting of a second bit area whose number of bits varies according to a degree to which the pattern is limited, and circulating the control information A cyclic redundancy check (CRC) parity bit is added and a scrambled control information is scrambled by scrambling a specific radio network temporary identifier (RNTI) to the added CRC parity bit. Downlink control information generation unit for outputting; And
And a transmitter for mapping the scrambled control information to a PDCCH and transmitting the PDCCH or the resource limit indicator to the terminal. The method of claim 1,
The resource allocation controller generates the resource limit indicator as any one of a physical layer signaling, a medium access control (MAC) message, and a radio resource control (RRC) message. Transmission of information. The method of claim 1,
And the downlink control information generation unit sets the second bit region to a fixed specific value. The method of claim 1,
The downlink control information generation unit scrambles the C-RNTI (Cell-RNTI) in the CRC parity bit that indicates that the control information is related to activation or deactivation of semi-persistent scheduling (SPS). And an apparatus for transmitting control information. In the transmission method of control information,
Defining a pattern in which an RB is allocated to a terminal;
Transmitting a resource limit indicator indicating the limitation of the pattern to the terminal;
Generating control information including a first bit area indicating a resource allocated to the terminal and a field including a second bit area whose number of bits varies according to a degree to which the pattern is limited;
Adding a CRC parity bit to the control information;
Scrambling a specific RNTI to the added CRC parity bit; And
And mapping the scrambled control information to a PDCCH and transmitting the scrambled control information to the terminal. The method of claim 5, wherein
The resource limit indicator is any one of physical layer signaling, MAC message and RRC message, transmission method of the control information. The method according to claim 6,
And the second bit area is set to a fixed specific value. The method according to claim 6,
And the specific RNTI is a C-RNTI indicating that the control information relates to activation or deactivation of an SPS. The method according to claim 6,
And the first bit region is encoded based on enumerative source coding representing discontinuous resource allocation by type 0.

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