KR100849329B1 - Method for assigning and signaling resources upon transmission for frequency diversity and therefore apparatus - Google Patents

Abstract

The present invention relates to a resource allocation and signaling method and apparatus in a communication system using a frequency division multiplexing scheme for transmitting data by allocating different frequency resources for each terminal. In a frequency division multiple access communication system, a resource allocation method includes allocating at least one subband among subbands mapped to subcarrier sets in a frequency domain to a terminal, wherein the subbands representing each subband The index is a result of performing bit inversion (BRO) in binary form with an offset indicating the position of the first subcarrier in the corresponding subcarrier set, and transmits resource allocation information indicating the allocated at least one subband to the terminal. And transmitting or receiving data with the terminal through at least one subcarrier set corresponding to the at least one subband indicated by the resource allocation information.

Frequency Division Multiple Access, Frequency Diversity, Resource Allocation, Mapping, Signaling

Description

Transmission resource allocation and signaling method and apparatus for frequency diversity {METHOD FOR ASSIGNING AND SIGNALING RESOURCES UPON TRANSMISSION FOR FREQUENCY DIVERSITY AND THEREFORE APPARATUS}

1 is an illustration of the minimum unit resources that can be allocated when transmitting data using frequency diversity technology.

2 is a diagram illustrating an example of allocating two or more subcarrier sets to one terminal according to the related art.

3 illustrates an example of assigning two or more subcarrier sets to a UE in accordance with a preferred embodiment of the present invention.

4 illustrates a tree signaling structure of resource allocation in accordance with a preferred embodiment of the present invention.

5A and 5B are structural diagrams of a transceiver for downlink transmission according to a preferred embodiment of the present invention.

6A and 6B are structural diagrams of a transceiver for uplink transmission according to a preferred embodiment of the present invention.

7 is a flowchart illustrating the operation of a base station for downlink transmission according to a preferred embodiment of the present invention.

8 is a flowchart illustrating operation of a UE for downlink reception according to a preferred embodiment of the present invention.

9 is a flowchart illustrating operation of a UE for uplink transmission according to a preferred embodiment of the present invention.

10 is a flowchart illustrating the operation of a base station for uplink reception according to a preferred embodiment of the present invention.

11 illustrates an example of resource allocation in an uplink DFDMA system according to an embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system using frequency division multiplexing (FDMA) scheme, and more particularly, to a method and apparatus for allocating resources for transmitting and receiving data using different frequency resources for each terminal. It is about.

In frequency division multiplexing, not only orthogonal frequency division multiplexing (OFDM) scheme that transmits data using a multi-carrier, but also 3rd generation partnership project (3GPP) LTE Single Carrier (SC) frequency modulation scheme (Single Carrier FDMA, hereinafter referred to as "SC-FDMA"), which has been proposed in Long Term Evolution, is included.

The factors that hamper high-speed, high-quality data services in wireless communication are largely due to the channel environment. In the wireless communication, the channel environment includes a Doppler due to power change, shadowing, movement of a terminal, and frequent speed change of a received signal caused by fading in addition to Additive White Gaussian Noise (AWGN). (doppler) effect, interference with other users and multipath signal (frequently changes).

Therefore, in order to support high speed and high quality data services in wireless communication, it is necessary to effectively overcome the above-mentioned obstacles. In a frequency division multiplexing system such as OFDM and SC-FDMA, a frequency diversity technique is one of transmission schemes and techniques used to overcome channel fading. The frequency diversity technique is a technique for uniformly experiencing good and bad channels by transmitting modulation symbols in one data packet over a wide band when good and bad phenomena of channels are repeated in the frequency domain. Among the modulation symbols included in one packet, there are symbols that experience bad channels and symbols that experience good channels, so the receiver can demodulate packets using the symbols that experienced the good channels. The frequency diversity technique is suitable for traffic that is not adaptable to a channel environment of a specific user such as a broadcast channel or a common control channel, or traffic that is sensitive to delay such as real time traffic.

1 is a diagram illustrating an example of a minimum unit resource that can be allocated when data is transmitted using frequency diversity technology.

Referring to FIG. 1, the subcarrier 110 is a basic unit of a frequency domain in an OFDM system, and frequency resources corresponding to a subcarrier may be used in SC-FDMA. In the present specification, in the case of an OFDM system and an SC-FDMA system, a basic unit of a frequency domain that can be used will be collectively referred to as a subcarrier. Subcarriers constituting the minimum unit resource should be evenly located throughout the band to efficiently obtain frequency diversity, but are not limited to a specific pattern. FIG. 1 illustrates a case in which subcarriers within a minimum unit resource are located at equal equidistance for convenience of description. Distributed FDMA (DFDMA), a transmission method using diversity technology in SC-FDMA, obtains a low peak to average power ratio (PAPR) due to a single carrier (SC) characteristic by placing subcarriers in a unit resource at regular intervals. Can be.

로 표시된 서브캐리어들로 구성되는 최소 단위 자원이다. 변수 R(130)은 할당 가능한 서브캐리어 세트의 수로서, 한 서브캐리어 세트(120) 내에서 서브캐리어들 간의 간격과도 같다. 서브캐리어 세트들은 각 서브캐리어 세트 별로 고유한 값인, 초기 서브캐리어의 위치를 나타내는 옵셋에 따라 독립적으로 정의되는데, 서브캐리어 세트(120)는 0이 옵셋을 갖는다. 상기 서브캐리어 세트 별 옵셋 값은 자원 할당 정보로 사용될 수 있다. Subcarrier set 120 is

The minimum unit resource composed of subcarriers indicated by. The variable R 130 is the number of assignable subcarrier sets, which is equal to the spacing between subcarriers within one subcarrier set 120. The subcarrier sets are independently defined according to an offset indicating the position of the initial subcarrier, which is a unique value for each subcarrier set, and the subcarrier set 120 has an offset of zero. The offset value for each subcarrier set may be used as resource allocation information.

As described above, the subcarrier set is the minimum unit that is the most basic resource allocation, and two or more subcarrier sets may be allocated to the terminal according to the amount of transmission data or the channel condition of the terminal. Since it is not efficient to signal each offset value for any subcarrier sets independently, it is preferable to allocate subcarrier sets having consecutive offset values to the terminal in order to reduce signaling overhead. .

2 illustrates an example of allocating two or more subcarrier sets to one terminal according to the related art.

Referring to FIG. 2, the displayed resource 210 represents subcarrier sets allocated to a user equipment (hereinafter, referred to as a “UE”) # 1. Variable R 220 refers to the spacing between subcarriers within one subcarrier set. Offset values of the subcarrier sets 210 assigned to the UE # 1 are 0 and 1.

As such, when subcarrier sets of consecutive offset values are allocated to one UE, the performance gains due to frequency diversity are limited because the subcarriers used by the UE have less spreading effect in the frequency domain. In particular, in DFDMA transmission, since the subcarriers allocated to a UE are not positioned at regular intervals, the single carrier characteristic disappears, causing a problem of increasing PAPR.

The present invention provides a method and apparatus for allocating frequency resources to maximize frequency diversity gain and signaling the allocated resources in a system based on a frequency division multiplexing (FDMA) scheme.

According to a preferred embodiment of the present invention, in a frequency division multiple access communication system,

Allocating at least one subband of the subbands mapped to the subcarrier sets in the frequency domain to the terminal, and the subband index representing each subband, the position of the first subcarrier of the corresponding subcarrier set Bit offset (BRO) is performed in binary form.

Transmitting resource allocation information indicating the allocated at least one subband to the terminal;

And transmitting or receiving data with the terminal through at least one subcarrier set corresponding to the at least one subband indicated by the resource allocation information.

In a preferred embodiment of the present invention, in a method for receiving frequency resources in a frequency division multiple access communication system,

Receiving resource allocation information indicating at least one subband allocated to the terminal among the subbands mapped to the subcarrier sets in the frequency domain from the base station, and the subband index indicating each subband is a corresponding subband. The offset indicating the position of the first subcarrier in the carrier set is the result of performing bit inverse (BRO) in binary form.

And transmitting or receiving data with the base station through at least one subcarrier set corresponding to the allocated at least one subband.

In a preferred embodiment of the present invention, in a base station apparatus for allocating frequency resources in a frequency division multiple access communication system,

A scheduler for allocating at least one subband of the subbands mapped to the subcarrier sets in the frequency domain to the terminal, wherein the subband index representing each subband is the position of the first subcarrier in the corresponding subcarrier set. Bit offset (BRO) is performed in binary form with an offset indicating.

A control channel transmitter for transmitting resource allocation information indicating the allocated at least one subband to the terminal;

And a data transceiver for transmitting or receiving data to and from the terminal through at least one subcarrier set corresponding to the at least one subband indicated by the resource allocation information.

In a preferred embodiment of the present invention, in a terminal device allocated frequency resources in a frequency division multiple access communication system,

A control channel receiver for receiving resource allocation information indicating at least one subband allocated to a terminal among subbands mapped to subcarrier sets in a frequency domain from a base station, and a subband index indicating each subband correspond to each other. Bit offset (BRO) in binary form with an offset indicating the position of the first subcarrier in the subcarrier set

And a data transceiver for transmitting or receiving data to and from the base station through at least one subcarrier set corresponding to the allocated at least one subband.

The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that those skilled in the art may better understand it from the following detailed description of the invention. In addition to these features and advantages, further features and advantages of the present invention which form the subject of the claims of the present invention will be better understood from the following detailed description of the invention.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art will recognize that the disclosed concept and specific embodiments of the invention described below may be changed or modified to achieve the technical problem to be achieved by the present invention. Those skilled in the art will also recognize that concepts and structures equivalent to the concepts and structures disclosed herein do not depart from the spirit and scope of the broadest form of the invention. It should be noted that reference numerals and like elements among the drawings are denoted by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

An important aspect of the present invention is a resource that can be implemented with simple signaling while sufficiently obtaining frequency diversity gain when allocating two or more subcarrier sets to one UE for transmitting data using frequency diversity technology. I would suggest an assignment. The proposed method can be applied without exception in transmission using diversity technology in frequency division multiplexing such as OFDM or SC-FDMA.

The present invention uses a subband index representing the subbands after reconstructing the minimum unit resources (ie, subcarrier sets) in the actual frequency domain into subbands that are logical unit resources corresponding one-to-one to corresponding offsets. Resource allocation. The mapping rule for mapping the offset of the subcarrier set and the subband index is presented in the following embodiments.

<< first embodiment >>

The first embodiment describes the mapping rule for the case where the maximum number of assignable subcarrier sets R is a power of two.

는 0 또는 1 중 하나의 값을 가진다. The offset of the subcarrier set in the frequency domain is defined as a variable x having an integer value between 0 and R-1, and the index of the corresponding subband is defined as a variable y in the same range. The variable x can be expressed as the sum of the squares of 2 as shown in Equation 1 below, and the corresponding variable y is obtained from Equation 3 using the coefficients of Equation 1. In this case, Q of Equation 1 is obtained from R according to Equation 2, and each coefficient corresponding to x used in Equations 1 and 3

Has a value of either 0 or 1.

As indicated above, it can be seen that the subband index corresponding to the offset (x) of the subcarrier set is the bit reverse-order (hereinafter referred to as BRO) in binary form.

Hereinafter, an example of defining a new subband index corresponding to an offset of a subcarrier set using Equations 1 to 3 when R = 16 and Q = 4 will be described.

,

,

,

이므로, 대응되는 서브밴드 인덱스는 하기 <수학식 5>와 같이 '10'이 된다.If x is '5', Equation 1 is expressed as Equation 4, and the coefficient values are

,

,

,

Therefore, the corresponding subband index is '10' as shown in Equation 5 below.

In other words, the offset '5' (= 0101) of the subcarrier corresponds to the subband index '10' (= 1010), where '1010' is a BRO result of '0101'.

As shown above, the overall result of reconstructing the offset (x) of the subcarrier set to the corresponding subband index (y) by using Equations 1 to 3 is shown in Table 1 below. . According to <Table 1>, the UE-specific offset used as signaling information of resource allocation in the existing technology may be replaced with a subband index. For example, if the index signaled to the UE is '1', the frequency resource actually allocated to the UE becomes a subcarrier set having an offset of 8.

Index (y) 0 One 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Offset (x) 0 8 4 12 2 10 6 14 One 9 5 13 3 11 7 5

3 shows an example of allocating two or more subcarrier sets to a UE according to the first embodiment of the present invention. By looking at the example of Figure 3, it is confirmed that the resource allocation method of the present invention efficiently obtains the frequency diversity gain.

로 표시된 서브캐리어들은 옵셋이 0인 서브캐리어 세트이고,

로 표현된 서브캐리어들은 옵셋이 8인 서브캐리어 세트이다. Referring to FIG. 3, a case of allocating two subcarrier sets to UE # 1 310 will be described. The offset (x) 311 and the subband index (y) 312 are the same as in Table 1, respectively, and R 313 is the number of assignable subcarrier sets, which is 16 here. When allocating subbands with subband indexes 0 and 1 to UE # 1 310, subcarrier sets with offsets 0 and 8 should be allocated in the real frequency domain. Resource 314 represents subcarrier sets 0, 8 assigned to UE # 1. Of the total subcarriers assigned to UE # 1 310,

Subcarriers denoted as 0 are subcarrier sets with an offset of 0,

The subcarriers represented by are subcarrier sets having an offset of 8.

A case where four subcarrier sets are allocated to UE # 2 320 will be described. Referring to Table 1, the subband indexes allocated to UE # 2 are 0,1,2,3, which is equivalent to the allocation of subcarrier sets of offsets 0,8,4,12 in the actual frequency domain. . Resource 321 represents four subcarrier sets 0, 8, 4, 12 assigned to UE # 2.

As can be seen from the above, when allocating frequency resources using the subband index as proposed in the present invention, even if two or more subcarrier sets are simultaneously allocated to one UE, all allocated subcarriers are uniformly located in all bands. Compared to the case shown in FIG. 2, a larger frequency diversity gain can be obtained.

As a modified embodiment, the case where R is one less than the square of two will be described. When R is one less than the power of two, the same as in the case of R being the power of two, the equations (1) through (5) mentioned above are used to calculate the offset (x) of the subcarrier set. It can be reconstructed with the corresponding subband index y, where the offset x of the subcarrier set is used only in the range of 0 to R-2. Then, using the above Equations 1 to 5, the overall result of reconstructing the offset (x) of the subcarrier set into the corresponding subband index (y) is shown in Tables 2 and 3 below. Same as>

Table 2 below shows offsets of the subcarrier set and corresponding subband indices when R is 3.

Index (y) 0 One 2 Offset (x) 0 2 One

Table 3 below shows the offsets of the subcarrier set and the corresponding subband indices when R is 7.

Index (y) 0 One 2 3 4 5 6 Offset (x) 0 4 2 6 One 5 3

<< 2nd Example >>

는 <수학식 8>과 같이 정의된다.

는 x를 M으로 나눈 나머지로 정의되므로, 0과 M-1 사이의 정수 값을 가진다. x에 대응하는 서브밴드 인덱스 y는 <수학식 9>과 같이 구해진다. <수학식 7> 및 <수학식 9> 에서 사용된 계수

는 0 또는 1 중 하나의 값을 가진다. In the second embodiment, an embodiment in which an offset of a subcarrier set is associated with a subband index when the number R of the maximum assignable subcarrier sets is not a power of two is described. When R is expressed as a product of an odd numbered portion and a portion corresponding to the square of 2, the variable x, which is an offset of subcarrier sets in the actual frequency domain, is expressed as shown in Equation 7 below. The variable Q and used in Equation 7

Is defined as in Equation 8.

Since x is defined as the remainder of x divided by M, it has an integer value between 0 and M-1. The subband index y corresponding to x is obtained as shown in Equation (9). Coefficients used in Equations 7 and 9

Has a value of either 0 or 1.

Where M is odd.

Hereinafter, an example of defining a new subband index corresponding to an offset of a subcarrier set using Equations 6 to 9 when R = 24 will be described.

When R = 24, when M = 3 and Q = 3 in Equation 6, and the offset (x) of the subcarrier set is '13', the corresponding subband index y is expressed by Equation 10. It becomes '9' together.

The entire result of reconstructing the offset (x) of the subcarrier set to the corresponding subband index (y) by using Equations 6 to 9 is shown in Table 4 below.

index (y) offset (x) 0 0 One 12 2 6 3 18 4 3 5 15 6 9 7 21 8 One 9 13 10 7 11 19 12 4 13 16 14 10 15 22 16 2 17 14 18 8 19 20 20 5 21 17 22 11 23 23

By using a mapping rule for reconstructing the offset of the subcarrier set into the subband index as described above, the maximum frequency diversity gain can be obtained when allocating consecutive subband indices. Hereinafter, an operation of signaling resource allocation using 1-D (1-Dimensional: 1D) signaling or tree structure signaling while using the above-described mapping rule will be described. Since R, the total number of allocable minimum unit resources, is a value determined in one cell, it may be broadcast or predetermined. Note that the present invention is not limited to the signaling method of R.

In a modified embodiment of the present invention, in the mapping relationship between the offset of the subcarrier set and the subband index, the offsets of the subcarrier sets are cyclically shifted by applying different cyclic shift values for each cell. This is to prevent the frequency resources actually used in the multiple cells from colliding with each other using the same order of subcarrier sets.

As an example, when subbands 0, 1, 2, and 3 in cell A sequentially correspond to subcarrier sets 0, 2, 1, and 3, in cell B, subbands 0, 1, 2, and 3 The subcarrier sets 2, 1, 3, and 0 correspond sequentially. Cell A then has a cyclic shift of 0 and cell B has a cyclic shift of 1. In this case, when one subband is allocated to corresponding UEs in each of the two cells, cell A allocates subband 0 (subcarrier set 0) to the UE in cell A, and cell B assigns subband 0 (subcarrier set 2). ) Is assigned to a terminal in cell B. Therefore, the inter-cell interference due to the collision of frequency resources in the physical layer is reduced.

In addition, the cyclic shift value of each cell may change at a predetermined time period. Specifically, in each cell, offsets of subcarrier sets are cyclically shifted by m for every N OFDM symbols. Where m is a cyclic shift value different for each cell.

In another modified embodiment, when a frequency resource available in one cell is divided into subband groups each consisting of a plurality of subbands, offsets of the subcarrier sets are generated for each subband group. Here, the subband group is a collection of subbands having similar frequency characteristics. For example, the base station performs scheduling on a subband group basis and allocates at least one subband arbitrarily selected within the selected subband group to the terminal.

For example, when subband group 1 includes subbands 0, 1, 2 and 3, the subbands in subband group 1 have corresponding subcarrier sets 0, 2, 1 and 3. In addition, when subband group 2 includes subbands 0, 1, 2, and 3 in the same cell, the subbands of subband group 1 have corresponding subcarrier sets 0, 2, 1, and 3. FIG. Since the subband groups are managed in the same cell, they have the same cyclic shift value for the subcarrier sets. However, cyclic shift is performed for each subband group.

In another modified embodiment, when the frequency resources available in one cell are divided into subband groups each consisting of several subbands, the offsets of the subcarrier sets are totally included in all the subband groups. Generated corresponding to the subbands. For example, when subband group 1 includes subbands 0, 1, 2, and 3 and subband group 2 includes subbands 4, 5, 6, and 7, the subbands of the subband groups are ordered. Corresponding to subcarrier sets 0, 4, 2, 6, 1, 5, 3, 7. Even in this case, the cyclic shift is performed by applying different cyclic shift values for each cell in each subband group. That is, the subcarrier sets {0, 4, 2, 6} and the subcarrier sets {1, 5, 3, 7} are cyclically shifted, respectively.

<< third embodiment >>

The third embodiment is for 1D signaling of resource allocation information. Since 1D signaling transmits resource allocation information of UEs located in one cell together, it is used in a signaling channel structure of MAP type in which each UE can demodulate not only its own resource allocation information but also resource allocation information of other UEs in a cell. It is possible. That is, if each UE knows all the resource allocation information of the other UEs, and resource allocation is performed in the order of successive subband indexes, each UE refers to the resource allocation information for all UEs and the actual frequency allocated to itself. Check the resource.

Resource allocation information transmitted for each UE when using the 1D signaling method includes a first (or last) subband index of the allocated resource. For example, in a case where R = 16 allocates four minimum unit resources to four UEs A, B, C, and D, each resource allocation information signaled to each UE includes a corresponding first subband index. do. That is, resource allocation information of UE A is '0', resource allocation information of UE B is '4', resource allocation information of UE C is '8', and resource allocation information of UE D is '12'.

In this case, UE C recognizes that resources allocated to UE C are subbands between subband indexes 8 to 11 with reference to resource allocation information of UE B and UE D. Referring to <Table 1> above, Note that the offsets of the assigned subcarrier sets in the frequency domain are 1, 9, 5, 13.

Even when the resource allocation information includes the last subband index, each UE recognizes the frequency resource allocated to itself by referring to its own resource allocation information and resource allocation information of other UEs. The amount of signaling required for such 1D signaling is log ₂ (16) = 4 bits for each UE. At this time, the mapping between the subband index and the offset of the subcarrier set is performed according to Equations 1 to 3 or Equations 6 to 9 previously proposed.

<< fourth embodiment >>

The fourth embodiment relates to tree structure signaling of resource allocation information. The minimum unit resources are expressed in a tree structure, and a node corresponding to the allocated resource is signaled to the terminal.

4 is a diagram illustrating a tree signaling structure of resource allocation according to an embodiment of the present invention.

Referring to FIG. 4, a tree structure in which R is 16 is shown, which has five layers 410, 411, 412, 413, 414, each of which includes at least one node 420. . Each node 420 is composed of an offset of R and a set of subcarriers, and is connected to a branch with one upper node and two lower nodes. In the above-described tree structure, the resources of each node of the remaining stages 411 to 414 except for the lowest stage 410 include resources of nodes (lower nodes) located in the lower stage.

Nodes 0 through 16 of the lowest stage 410 correspond to 16 minimum unit resources, i.e., subcarrier sets. The subcarrier sets of the lowest stage 410 are listed in the order of the corresponding subband index, and the offset of the subcarrier set corresponding to each subband index is expressed as one of nodes 0 to 15 together with R = 16. Since each of the nodes 16 to 23 of the second lower stage 411 means two subcarrier sets, R = 8. Since subcarrier sets 0 and 8 at R = 16 in the lowest stage 410 are the same as subcarrier set 0 when R = 8 in the second lower stage 411, node 16 is equal to node 0 and node. It means to allocate 1's resources together.

Similarly, each of nodes 24 to 27 of the third lower stage 412 means four subcarrier sets, and node 24 means a resource whose offset of the subcarrier set is 0 when R = 4, so that R = 16. When the offset of the subcarrier sets is equal to a resource of 0, 8, 4, 12. Each of nodes 28 and 29 of the third lower stage 413 represents eight subcarrier sets, and node 30 of the highest stage 414 represents 16 subcarrier sets, that is, all frequency resources.

Since the total number of nodes is 31 through the stages 410 to 414 of the tree structure, each node may be represented and signaled by 5 bits as shown in Table 5 below. When all resources are allocated equally to UEs A, B, C, and D, the resource allocation information of UE C includes '11010' representing node 26, and the resource allocation information includes subband indexes 8-11, That is, it means subcarrier sets having offsets of 1, 9, 5, and 13.

Bits resources bits resources bits resources bits resources 00000 node 0 01000 node 8 10000 node 16 11000 node 24 00001 node 1 01001 node 9 10001 node 17 11001 node 25 00010 node 2 01010 node 10 10010 node 18 11010 node 26 00011 node 3 01011 node 11 10011 node 19 11011 node 27 00100 node 4 01100 node 12 10100 node 20 11100 node 28 00101 node 5 01101 node 13 10101 node 21 11101 node 29 00110 node 6 01110 node 14 10110 node 22 11110 node 30 00111 node 7 01111 node 15 10111 node 23 11111 reserved

In the above example, although the number of signaling bits required for resource allocation information is 5 bits, unlike 1D signaling in which each UE must also interpret resource allocation information of other UEs, its own resource allocation information can recognize an allocated resource only. Can be. In addition, since each node of the tree structure represents resources of a continuous index, maximum frequency diversity gain can be obtained even if any node is allocated. At this time, the mapping between the subband index and the offset of the subcarrier set is performed according to Equations 1 to 3 above.

(여기서 M은 홀수)이다.The mapping rule and signaling proposed by the present invention can be used without being limited to the minimum number of unit resources allocated to a UE or a resource allocation algorithm. If one UE wants to allocate subcarriers at regular intervals, the constraints described below may be added. An example of such a case is an LTE uplink DFDMA system, which is based on allocating subcarriers at regular intervals to each UE for low PAPR. In the following, we will look at the constraints to apply the present invention in DFDMA. The following description applies in common to both the case where R is a power of two and the case of non-power of two. In other words,

Where M is odd.

)의 제약들은 다음과 같다.1.When R is the power of 2

) Are as follows.

■ Constraints 1.1: Number of minimum unit resources that can be allocated (N):

Constraint 1.2: index of the first minimum unit resource (k):

, 여기서 M은 1을 제외한 홀수)의 제약들은 다음과 같다.2. When R is not a power of two (

, Where M is an odd number except 1)

■ Constraints 2.1: Number of minimum unit resources that can be allocated (N):

Restriction 2.2: Index of first minimum unit resource (k):

In the following, an example of resource allocation in a DFDMA system when R = 12 and Q = 2 will be described. When R = 12, the mapping relationship between the offset (x) and the subband index (y) of the subcarrier set obtained using Equations 6 to 9 is shown in Table 6 below.

index (y) offset (x) 0 0 One 6 2 3 3 9 4 One 5 7 6 4 7 10 8 2 9 8 10 5 11 11

According to the constraint 2.1, the number of minimum unit resources allocable is 0,1,2,4,12. In allocating the entire resource to six UEs A to F, UE A is allocated four minimum unit resources, UEs B, C, and D each have two minimum unit resources, and UEs E and F Is allocated one minimum unit resource each. According to the constraint 2.2, subband indexes 0, 4 and 8 may be used as the first minimum unit resource of UE A, and subband indexes 0, 2 and 4 may be used as the first minimum unit resource of the UE of UEs B, C and D. , 6, 8, 10 are possible, and the first minimum unit resources of UEs E and F are all subband indexes 0, 1, 2, 3, 4, 5, 6, 7, 9, 10, and 11. . Accordingly, while satisfying the above constraints, the resources allocated to each UE may be variously allocated so as not to overlap.

When the subband index of the first minimum unit resource is signaled for each user using 1D signaling of the MAP scheme, UE A receives the subband index 0, UE B receives the subband index 4, and UE C the subband. Index 6, UE D is assigned subband index 8, and UEs E, F are assigned subband indexes 10 and 11, respectively. According to the mapping relationship of Table 4, the offsets of subcarrier sets used by UE A are 0, 3, 6, and 9, UE B uses subcarrier sets 1 and 7, and UE C uses subcarriers. Sets 4 and 10, UE D will use subcarrier sets 2 and 8, UE E will use subcarrier set 5, and UE F will use subcarrier set 11.

FIG. 11 illustrates subcarrier sets allocated to respective users in a frequency domain in an uplink DFDMA system according to an exemplary embodiment of the present invention. As illustrated, resources 1110 to 1160 include UEs A, B, Subcarrier sets allocated for C, D, E, F. It can be seen that the spacing of subcarriers assigned to each user is constant.

Since the scheduling for resource allocation in a cellular system is an operation occurring at the base station, the base station knows the scheduled resource allocation information. The above-described signaling means an operation of transmitting resource allocation information to the UE by the base station regardless of the uplink / downlink.

In the case of downlink transmission, the base station transmits data through resources allocated to each UE, and the UE demodulates data received from the base station through resources allocated to the base station using resource allocation information from the base station.

5A and 5B are structural diagrams of a transceiver for downlink transmission according to a preferred embodiment of the present invention, which shows the structure of a base station and a UE when OFDM is used in downlink.

Referring to FIG. 5A, the base station transmitter 510 shows a transmission structure of a base station in downlink. A downlink scheduler 511 determines downlink resource allocation information for downlink, wherein the UE's modulation and coding scheme (MCS) method as well as the resource allocation information indicating the resources allocated to each UE are determined. Control information including format information about a data channel such as the above is generated.

The data symbol generator for UE # 1 512, the data symbol generator 513 for UE # 2, and the data symbol generator 514 for UE # N are the forward schedulers ( Data symbols for each UE are generated based on the control information from 511. The data symbol generators 512 to 514 may include an error correction encoder, a rate matcher, an interleaver, a symbol modulator, and the like, and thus the description and description thereof will be omitted.

The data symbols generated by the data symbol generators 512 to 514 are inputted to a serial to parallel converter (S / P) 515 and converted into parallel signals, and then mapped to a mapper 516. Is entered. The mapper 516 serves to map the parallel-converted data symbols to frequency resources allocated for each UE, and the mapped frequency resources are a subband index indicated by resource allocation information from the downlink scheduler 511 or The actual subcarriers are determined by the offset of the subcarrier sets. In addition, the mapper 516 maps the control information from the downlink scheduler 511 to a control channel resource, which is the same as the frequency resources allocated to each UE according to the signaling scheme used, or It can be a resource common to all UEs.

Data symbols and control information of all UEs mapped to subcarriers that are actual frequency resources in the mapper 516 are time-domain in an Inverse Fast Fourier Transfer block (hereinafter referred to as "IFFT") 517. To a signal.

The time domain signal is converted into OFDM samples which are serial signals in a parallel to serial converter (P / S) 518 and input to a guard interval inserter 519. do. The guard interval inserter 519 inserts guard interval samples into the OFDM samples. In general, the guard interval samples have a cyclic prefix (CP) which repeats some of the OFDM samples. do. The OFDM transmission symbol, which is the output of guard interval inserter 519, is transmitted over a radio channel through transmit antenna (s) 520.

Referring to FIG. 5B, the UE receiver 530 illustrates a reception structure of the UE in downlink. Signals received through the receive antenna (s) 531 are removed with guard interval samples from a guard interval remover 532 and input to a S / P converter 533 as parallel signals. Is converted. The parallel signal, which is an output of the S / P converter 533, is converted into a frequency domain signal by a fast Fourier transfer block 534 (FFT) 534.

Control signals mapped to control channel resources among the frequency domain signals output from the FFT 534 are input to a control channel decoder 535 and restored as control information. The demapper 536 receives the frequency domain signal, which is the output of the FFT 534, as an input, and then allocates the frequency domain signal to the corresponding UE using resource allocation information in the control information recovered by the control channel decoder 535. The data signal transmitted through the frequency resource is extracted from the frequency domain signal. The resource allocation information is determined according to the mapping relationship between the offset of the subband index and the subcarrier set, and the mapping relationship is defined according to the equations proposed in one of the above-described embodiments of the present invention.

The data signal for the corresponding UE separated at the demapper 536 is converted to a serial signal at the parallel / serial converter (P / S) 537 and then decoded at the data channel decoder 538 to be recovered as data symbols. Control information from the control channel decoder 535 is used in the recovery of the data symbols.

In case of uplink transmission, the UE receives resource allocation information from the base station and then transmits data to the base station through the resource indicated by the resource allocation information.

6A and 6B are structural diagrams of a transceiver for uplink transmission according to a preferred embodiment of the present invention, and show structures of a base station and a UE when SC-FDMA is used in uplink. In the SC-FDMA system, data symbols are generated in the time domain, converted into frequency domain signals through the FFT 614, mapped to frequency resources, and then converted into time domain signals through the IFFT 616.

Referring to FIG. 6A, the UE transmitter 610 shows a transmission structure of a UE in downlink. The control channel decoder 611 decodes the control information received through the downlink in the previous slot, and outputs resource allocation information indicating the frequency resource allocated to the corresponding UE and format information necessary for generating data. The data symbol generator 612 generates data symbols based on the format information and outputs the data symbols to the S / P converter 613. The data symbols are converted into parallel signals in serial / parallel converter (S / P) 613 and then converted into frequency domain signals in FFT 614. In this case, the size of the FFT 614 is equal to the number of data symbols generated by the data symbol generator 612.

The frequency domain signal, which is the output of the FFT 614, is mapped to input taps of the IFFT 616 corresponding to subcarriers of the frequency resource assigned to the UE by the mapper 615, which frequency resource is mapped to a control channel decoder ( In 611, it is indicated by the resource allocation information recovered. The IFFT 616 converts the signal input from the mapper 615 into a time domain signal, where the size of the IFFT 616 is equal to the total number of subcarriers including the guard period GI.

The time domain signal is converted into OFDM samples which are serial signals by a parallel / serial converter (P / S) 617 and input to a guard interval inserter (618). The guard interval inserter 618 inserts guard interval samples into the OFDM samples. In general, guard interval samples are in the form of a CP that repeats some of the OFDM samples. The OFDM transmit symbol, which is the output of guard interval inserter 618, is transmitted over a radio channel through transmit antenna (s) 619.

Referring to FIG. 6B, the base station receiver 630 shows a reception structure of a base station in downlink. Signals received through the receive antenna (s) 631 are removed from the guard interval remover 632, and are input to a serial / parallel converter (S / P) 633 and converted into parallel signals. The parallel signal, which is the output of the serial / parallel converter (S / P) 633, is converted into a frequency domain signal at the FFT 634 and output.

The frequency domain signal, which is the output of the FFT 634, is input to the demapper 635 and separated into received signals for each UE. In performing the demapping operation, the demapper 635 uses UE-specific resource allocation information determined by the uplink scheduler 636. Received signals divided for each UE in the demapper 635 are input to the data channel receivers 640, 650, and 660 for each UE. The data channel receivers 640, 650, and 660 have the same structure, and typically, the data channel receiver 640 includes an IFFT 641, a parallel / serial converter (P / S) 642, and a data symbol demodulator (Data). symbol decoder 643.

The IFFT 641 receives a received signal through a frequency resource corresponding to UE1 as an input and converts it into a time domain signal, and the serial / parallel converter 642 converts the time domain signal into a serial signal. The serial signal, which is the output of the serial / parallel converter 642, is restored to the transmission data via a data symbol demodulator 643. The data channel receivers 640, 650, and 660 perform similar operations on received signals of frequency resources corresponding to UE # 1, UE # 2, and UE # N, respectively.

7 is a flowchart illustrating the operation of a base station for downlink transmission according to a preferred embodiment of the present invention.

Referring to FIG. 7, in step 720, the base station performs downlink scheduling based on channel information of each UE. The scheduling generates resource allocation information and format information necessary for data generation (including modulation and error encoding) for each UE. In operation 730, UE-specific data symbols are generated based on the format information. In operation 740, the data symbols are mapped to resources, that is, subcarriers, in an actual frequency domain based on the resource allocation information. The frequency mapped signal is converted into a time domain signal in step 750 and transmitted over a wireless channel.

8 is a flowchart illustrating an operation of a UE for downlink reception according to a preferred embodiment of the present invention.

Referring to FIG. 8, in step 820, the UE recovers control information for downlink by separating a control channel signal transmitted through a predetermined control channel resource from a downlink received signal. Based on the control information, in step 830, the UE determines whether there is a resource allocated to the UE and whether data is transmitted. If there is an allocated resource and data is transmitted through the allocated resource, the flow proceeds to step 840 where the UE separates and receives only the received signal of the UE through the allocated resource, and receives the received signal in step 850. Recover data symbols based on. If the allocated resource does not exist or data is not transmitted in step 830, the operation ends.

9 is a flowchart illustrating the operation of a UE for uplink transmission according to a preferred embodiment of the present invention.

Referring to FIG. 9, in step 920, the UE demodulates a control channel signal received through downlink to obtain control information for uplink. Then, in step 930, the UE transmits uplink to the UE based on the control information. It is determined whether frequency resources are allocated. If there is a frequency resource allocated to the UE, the UE proceeds to step 940 and the UE generates data symbols for uplink transmission, and in step 950 maps the data symbols to subcarriers of the allocated frequency resource to the base station. send. Meanwhile, if it is determined in step 930 that there is no frequency resource allocated to the UE, the operation ends.

10 is a flowchart illustrating the operation of a base station for uplink reception according to a preferred embodiment of the present invention.

Referring to FIG. 10, the base station receives an uplink signal in step 1020, and separates a received signal for each UE from the uplink signal based on uplink resource allocation information determined in step 1030. In step 1040, the base station recovers data symbols from the UE-specific signals.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

In the present invention operating as described in detail above, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

According to the present invention, even when allocating two or more subcarrier sets to one UE, it is possible to simply signal resource allocation information without sufficiently increasing the signaling overhead while sufficiently obtaining a frequency diversity gain and obtaining a single carrier effect, thereby allocating resource allocation. There is an advantage that can be performed effectively.

Claims (32)

A method of allocating frequency resources in a frequency division multiple access communication system, Allocating at least one subband of the subbands mapped to the subcarrier sets in the frequency domain to the terminal, and the subband index representing each subband, the position of the first subcarrier of the corresponding subcarrier set Bit offset (BRO) is performed in binary form. Transmitting resource allocation information indicating the allocated at least one subband to the terminal; And transmitting or receiving data with the terminal through at least one subcarrier set corresponding to the at least one subband indicated by the resource allocation information. The method of claim 1, further comprising allocating subbands having consecutive subband indices among the subbands to the terminal. The method of claim 1, wherein the resource allocation information, Nodes in the lowest stage represent the subband indices, respectively, nodes in the uppermost stage represent the entire subbands, and nodes in at least one intermediate stage are connected to one upper node and two lower nodes, respectively, to the lower node. And a node indicative of the allocated at least one subband in a tree structure representing subband indices. The method of claim 1, wherein the resource allocation information, And a first or last subband index of each resource allocated to the communicating terminals in the cell. 2. The method of claim 1, wherein when the number R of assignable subcarrier sets is a square number of 2, the subcarrier sets are mapped to the subbands according to the following equation.

Where x is an offset of the subcarrier set and y _x is a subband index corresponding to offset x of the subcarrier set. 2. The method of claim 1, wherein when the number R of assignable subcarrier sets is not a power of two, the subcarrier sets are mapped to the subbands according to the following equation.

, Where M is odd

Where x is an offset of the subcarrier set and y _x is a subband index corresponding to offset x of the subcarrier set. 2. The method of claim 1, wherein when the number R of assignable subcarrier sets is one less than the square of two, the subcarrier sets are mapped to the subbands according to the following equation. .

Where x is an offset of the subcarrier set, y _x is a subband index corresponding to offset x of the subcarrier set, and offset (x) of the subcarrier set has a range from 0 to (R-2). A method for receiving frequency resources in a frequency division multiple access communication system, Receiving resource allocation information indicating at least one subband allocated to the terminal among the subbands mapped to the subcarrier sets in the frequency domain from the base station, and the subband index indicating each subband is a corresponding subband. The offset indicating the position of the first subcarrier in the carrier set is the result of performing a bit inversion (BRO) in binary form. And transmitting or receiving data with the base station through at least one subcarrier set corresponding to the allocated at least one subband. The method of claim 8, wherein the resource allocation information indicates subbands having consecutive subband indices among the subbands. The method of claim 8, wherein the resource allocation information, Nodes in the lowest stage represent the subband indices, respectively, nodes in the uppermost stage represent the entire subbands, and nodes in at least one intermediate stage are connected to one upper node and two lower nodes, respectively, to the lower node. And a node indicative of the allocated at least one subband in a tree structure representing subband indices. The method of claim 8, wherein the resource allocation information, And a first or last subband index of each resource allocated to the communicating terminals in the cell. 9. The method of claim 8, wherein when the number R of assignable subcarrier sets is a square number of 2, the subcarrier sets are mapped to the subbands according to the following equation.

Where x is an offset of the subcarrier set and y _x is a subband index corresponding to offset x of the subcarrier set. 10. The method of claim 8, wherein when the number R of assignable subcarrier sets is not a power of two, the subcarrier sets are mapped to the subbands according to the following equation.

, Where M is odd

Where x is an offset of the subcarrier set and y _x is a subband index corresponding to offset x of the subcarrier set. 9. The method of claim 8, wherein when the number R of assignable subcarrier sets is one less than the square of two, the subcarrier sets are mapped to the subbands according to the following equation. .

Where x is an offset of the subcarrier set, y _x is a subband index corresponding to offset x of the subcarrier set, and offset (x) of the subcarrier set has a range from 0 to (R-2). A base station apparatus for allocating frequency resources in a frequency division multiple access communication system, A scheduler for allocating at least one subband of the subbands mapped to the subcarrier sets in the frequency domain to the terminal, wherein the subband index representing each subband is the position of the first subcarrier in the corresponding subcarrier set. Bit offset (BRO) is performed in binary form with an offset indicating. A control channel transmitter for transmitting resource allocation information indicating the allocated at least one subband to the terminal; And a data transceiver for transmitting or receiving data to and from the terminal through at least one subcarrier set corresponding to the at least one subband indicated by the resource allocation information. The method of claim 15, wherein the scheduler, And assigning subbands having consecutive subband indices among the subbands to the terminal. The method of claim 15, wherein the resource allocation information, Nodes in the lowest stage represent the subband indices, respectively, nodes in the uppermost stage represent the entire subbands, and nodes in at least one intermediate stage are connected to one upper node and two lower nodes, respectively, to the lower node. And a node indicative of the assigned at least one subband in a tree structure representing the subband indices of the subbands. The method of claim 15, wherein the resource allocation information, A base station apparatus, characterized in that it comprises the first or last subband index of each of the resources allocated to the communicating terminals in the cell. 16. The base station apparatus according to claim 15, wherein when the number R of assignable subcarrier sets is a square number of 2, the subcarrier sets are mapped to the subbands according to the following equation.

Where x is an offset of the subcarrier set and y _x is a subband index corresponding to offset x of the subcarrier set. 16. The base station apparatus according to claim 15, wherein when the number R of assignable subcarrier sets is not a power of two, the subcarrier sets are mapped to the subbands according to the following equation.

, Where M is odd

Where x is an offset of the subcarrier set and y _x is a subband index corresponding to offset x of the subcarrier set. 16. The base station apparatus according to claim 15, wherein when the number R of assignable subcarrier sets is one less than the square of two, the subcarrier sets are mapped to the subbands according to the following equation.

Where x is an offset of the subcarrier set, y _x is a subband index corresponding to offset x of the subcarrier set, and offset (x) of the subcarrier set has a range from 0 to (R-2). In a terminal device allocated frequency resources in a frequency division multiple access communication system, A control channel receiver for receiving resource allocation information indicating at least one subband allocated to a terminal among subbands mapped to subcarrier sets in a frequency domain from a base station, and a subband index indicating each subband correspond to each other. Bit offset (BRO) in binary form with an offset indicating the position of the first subcarrier in the subcarrier set And a data transceiver for transmitting or receiving data to and from the base station through at least one subcarrier set corresponding to the allocated at least one subband. The terminal apparatus of claim 22, wherein the resource allocation information indicates subbands having consecutive subband indices among the subbands. The method of claim 22, wherein the resource allocation information, Nodes in the lowest stage represent the subband indices, respectively, nodes in the uppermost stage represent the entire subbands, and nodes in at least one intermediate stage are connected to one upper node and two lower nodes, respectively, to the lower node. And a node representing the allocated at least one subband in a tree structure representing the subband indices. The method of claim 22, wherein the resource allocation information, And a first or last subband index of each resource allocated to the communicating terminals in the cell. 23. The terminal apparatus according to claim 22, wherein when the number R of assignable subcarrier sets is a square number of 2, the subcarrier sets are mapped to the subbands according to the following equation.

Where x is an offset of the subcarrier set and y _x is a subband index corresponding to offset x of the subcarrier set. 23. The terminal apparatus according to claim 22, wherein when the number R of assignable subcarrier sets is not a square number of 2, the subcarrier sets are mapped to the subbands according to the following equation.

, Where M is odd

Where x is an offset of the subcarrier set and y _x is a subband index corresponding to offset x of the subcarrier set. 23. The terminal apparatus according to claim 22, wherein when the number R of assignable subcarrier sets is one less than the square of two, the subcarrier sets are mapped to the subbands according to the following equation.

Where x is an offset of the subcarrier set, y _x is a subband index corresponding to offset x of the subcarrier set, and offset (x) of the subcarrier set has a range from 0 to (R-2). A method for allocating frequency resources in a frequency division multiple access communication system, Mapping to subbands corresponding to subcarrier sets in the frequency domain, and the subband index representing each subband is a bit inversion in binary form of an offset indicating a position of the first subcarrier in the corresponding subcarrier set. (BRO), and the offsets of the subcarrier sets are cyclically shifted using different cyclic shift values for each cell. Allocating at least one of the subbands to the terminal; Transmitting resource allocation information indicating the allocated at least one subband to the terminal; And transmitting or receiving data with the terminal through at least one subcarrier set corresponding to the at least one subband indicated by the resource allocation information. 30. The method of claim 29, wherein when the number R of assignable subcarrier sets is a square number of two or less than one than the square number of two, the subcarrier sets are mapped to the subbands according to the following equation. Resource allocation method.

Where x is the offset of the subcarrier set, y _x is the subband index corresponding to the offset x of the subcarrier set, and x is in the range of 0 to (R-2) when R is one less than the power of two. Having The method of claim 29, wherein the cyclic shift value, A resource allocation method characterized by having a value that changes for each predetermined number of OFDM symbols. 30. The method of claim 29, further comprising cyclically shifting offsets of subcarrier sets corresponding to the subbands in the subband group consisting of a predetermined number of subbands using the cyclic shift value. Resource allocation method.

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