KR20070093657A - Method and apparatus for allocating resource in orthogonal frequency division multiple access system - Google Patents

Abstract

A method and an apparatus for allocating resources in an OFDMA(Orthogonal Frequency Division Multiple Access) system are provided to solve a problem that a common data control channel should transfer a large amount of information up to a terminal far away from a transmitter. Multiple data control channels are received by using a base station and a particular time-frequency resource. The number of DRCHs(Distributed Resources Channels) and LRCHs(Localized Resources Channels) constituting data channels is checked through the received data control channels. The data control channels are a PDCCH(Primary Data Control Channel) and an SDCCH(Secondary Data Control Channel).

Description

Resource allocation method and apparatus in orthogonal frequency multiple access system {METHOD AND APPARATUS FOR ALLOCATING RESOURCE IN ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS SYSTEM}

1 is a view showing an example of resources in the time and frequency domain in a typical OFDM-based wireless communication system,

2 illustrates an example of allocating resources using a DRCH method in a general OFDMA system.

3 is a diagram illustrating an example of allocating resources using an LRCH method in a general OFDMA system;

4 shows that LRCH (4,0), LRCH (4,1), LRCH (4,2), using the remaining resources after DRCH (16,0) and DRCH (16,8) are allocated first in a typical OFDMA system. A diagram showing an example of resource allocation constituting the LRCH (4,3),

FIG. 5 is a diagram illustrating an example in which a DRCH is configured using the remaining resources after LRCH (4,2) is allocated in a typical OFDMA system.

6 is a diagram illustrating an example of allocating 16 resources in an OFDMA mobile communication system according to an embodiment of the present invention;

7 is a diagram illustrating an example of allocating resources using SDCCH0 when one UE belongs to three CQI groups with 40 DRCHs according to an embodiment of the present invention;

8 is a diagram illustrating an example of allocating resources by using SDCCH1 when eight UEs belonging to three CQI groups are assigned to 40 DRCHs according to an embodiment of the present invention;

9 is a diagram illustrating an example of allocating resources by using SDCCH2 when three UEs belonging to three CQI groups are assigned to 40 DRCHs according to an embodiment of the present invention;

10 is a flowchart illustrating a method for allocating resources to at least one terminal by a base station in an orthogonal frequency division multiple access mobile communication system according to an embodiment of the present invention;

11 is a flowchart illustrating a method for a user equipment to allocate resources from a base station in a mobile communication system using an orthogonal frequency division multiple access scheme according to an embodiment of the present invention;

12 is a block diagram of a base station for allocating time-frequency resources to at least one terminal in an orthogonal frequency division multiplexing mobile communication system according to an embodiment of the present invention;

13 is a block diagram of a terminal for receiving a resource from the base station according to an embodiment of the present invention in an orthogonal frequency division multiplexing mobile communication system.

The present invention relates to a method and apparatus for allocating resources in a wireless communication system, and more particularly, to a method and apparatus for allocating resources in an orthogonal frequency division multiple access mobile communication system.

In general, a wireless communication system is a system developed for a case in which a fixed wired network cannot be connected to a terminal and used. Representative systems of such a wireless communication system include a wireless LAN, Wibro, a mobile ad hoc network, as well as a general mobile communication system providing voice and data services.

Recently, orthogonal frequency division multiplexing (OFDM) schemes have been actively studied and utilized in wireless communication systems, and the OFDM scheme uses multi-carriers. As a method of transmitting data by transmitting a plurality of sub-carriers, that is, a plurality of sub-carriers, that are mutually orthogonal, Multicarrier Modulation (MCM) is a type of multicarrier modulation that is modulated and transmitted.

The wireless communication system using the multi-carrier transmission method was first applied to military radio in the late 1950s, and the OFDM method, which is a representative multi-carrier transmission method overlapping a plurality of orthogonal subcarriers, began to develop in the 1970s. The OFDM method converts symbol strings serially input in parallel and modulates each of them through a plurality of subcarriers having mutual orthogonality. The OFDM method uses digital audio broadcasting (DAB). And digital transmission technologies such as digital television, wireless local area network (WLAN), and wireless asynchronous transfer mode (ATM).

The OFDM scheme is a system suitable for a wireless communication environment in which a linear signal component (LOS) is not guaranteed in a multipath, and is known to provide an efficient platform for high-speed data transmission by using the strong advantage in multipath fading. . That is, the OFDM divides all channels into narrowband subchannels having a plurality of orthogonalities and transmits them, thereby efficiently overcoming selective fading of frequencies.

In addition, the OFDM scheme inserts a cyclic prefix (CP) longer than the delay spread of the channel at the front of the symbol, thereby eliminating inter-symbol interference (ISI). Most effective. Due to these advantages, IEEE802.16a has been standardized, and 802.16a supports Single Carrier System, OFDM, and OFDMA.

Here, the Orthogonal Frequency Division Multiplexing Access (OFDMA) divides a frequency domain into subchannels consisting of a plurality of subcarriers, divides the time domain into a plurality of time slots, and allocates subchannels for each user to allocate both time and frequency domains. It is a multiple access method that can accommodate a large number of users with limited frequency resources by performing resource allocation.

1 is a view showing an example of resources in the time and frequency domain in a typical OFDM-based wireless communication system.

In a typical OFDM system, since one modulation symbol (for example, QPSK or 16 QAM, etc.) is generally transmitted through one subcarrier, the subcarriers are basic resources. In FIG. 1, the horizontal axis represents the time axis and the vertical axis represents the frequency axis. In FIG. 1, reference numeral 101 denotes one subcarrier, and reference numeral 102 denotes one OFDM symbol. As shown in FIG. 1, one OFDM symbol is generally composed of a plurality of subcarriers. In addition, in the conventional OFDM system, as shown by reference numeral 103, a plurality of OFDM symbols are bundled into one and configured as a basic transmission unit. Hereinafter, a basic transmission unit composed of the multiple OFDM symbols will be referred to as a transmission time interval (TTI). Therefore, as shown in FIG. 1, one TTI is composed of a plurality of OFDM symbols. When one smallest rectangle shown in FIG. 1 is called a “time-frequency bin”, it can be seen that one TTI includes a plurality of time-frequency bins. On the other hand, in a conventional OFDM system, the one TTI is generally composed of a plurality of physical channels. The physical channel refers to channels for transmitting various kinds of information, such as a paging channel, a packet data channel, a packet data control channel, and a reverse scheduling channel, which are required in a conventional mobile communication system. For example, referring to FIG. 1, some resources, that is, some time-frequency bins, are used for a paging channel, some resources are used as a common control channel for providing system information, and some resources in one TTI. It is used as a packet data channel for transmitting user data, and some resources are also used as a packet data control channel for transmitting control information for demodulation of the packet data channel. Although not mentioned above, it should be noted that other physical channels may exist for other purposes.

As described above, the conventional OFDM-based wireless communication system has two-dimensional resources in the time and frequency domain, and these time-frequency two-dimensional resources may be divided into small chunks and allocated to a plurality of terminals. At this time, since the amount of resources required for different terminals are different from each other, the resources allocated to each terminal, that is, time-frequency bins, should be efficiently promised and indicated between the transmitter / receiver. For example, when 5000 bins exist in one TTI as described above, the transmitter allocates 1 to 100 times to the first receiver and 101 to 600 to the second receiver. Be able to communicate effectively. To this end, when one allocated resource is indicated as described above, a method of individually indicating one subcarrier such as several subcarriers in a few OFDM symbols is very inefficient. This is because, in such a method, too much information is required to inform which terminal is assigned what resource.

In order to solve this problem, LRCH (Localized Resources), which is composed of two-dimensional resources in one TTI, that is, a plurality of time-frequency bins, constitutes a channel by combining adjacent resources among two-dimensional resources in the TTI. The allocated resource may be indicated by using a channel (DRV) method and a distributed resources channel (DRCH) method of configuring a channel by combining resources separated from each other with a specific rule among two-dimensional resources in a TTI.

First, DRCH (N, k) refers to a resource corresponding to the k-th group when the time and frequency resources in the TTI are divided into N groups having a distributed or scattered shape.

FIG. 2 is a diagram illustrating an example of allocating resources using a DRCH method in a general OFDMA system.

 Referring to FIG. 2, eight OFDM symbols exist in one TTI. Each OFDM symbol is indicated from L = 0 to L = 7. The one OFDM symbol consists of 32 subcarriers. 32 subcarriers included in the one OFDM symbol are indicated by n = 0 and n = 31. In FIG. 2, resources corresponding to DRCH (8, 0) where N = 8 and k = 0 are indicated by diagonal lines having the same reference numeral 200. A method of configuring a resource of the DRCH (8, 0) is as follows.

32 subcarriers in each OFDM symbol are divided into N (N = 8 in FIG. 2) groups. The subcarriers included in each group have the same distance in frequency. That is, subcarriers belonging to 'group 0' are n subcarriers corresponding to n = {0, 8, 16, 24}, and subcarriers belonging to 'group 1' are n = {1, 9, 17, 25}. The corresponding subcarriers, subcarriers belonging to 'group 2' are subcarriers corresponding to n = {2, 10, 18, 26}, and subcarriers belonging to 'group 3' are n = {3, 11, 19, 27} subcarriers.

Subcarriers belonging to 'Group 4' are subcarriers corresponding to n = {4, 12, 20, 28}, and subcarriers belonging to 'Group 5' are provided at n = {5, 13, 21, 29}. Corresponding subcarriers, subcarriers belonging to 'group 6' are subcarriers corresponding to n = {6, 14, 22, 30}, and subcarriers belonging to 'group 7' are n = {7, 15, 23 , 31} subcarriers.

As described above, when N = 8, the subcarriers included in each group in each OFDM symbol have the same distance in the frequency domain. Finally, the resources in the frequency and time domain corresponding to DRCH (8, 0) are defined by the sequence S unique to each base station. The sequence S has an element equal to the number of OFDM symbols included in one TTI. That is, since the sequence S designates the position of the DRCH for every symbol, the sequence S has as many elements as the number of symbols, and in the example below, elements such as 0, 3, 1, and the like. Referring to FIG. 2, the sequence S = {0, 3, 1, 7, 2, 6, 4, 5}. The sequence is an index indicating a group in each OFDM symbol.

In other words, in the base station defined as S = {0, 3, 1, 7, 2, 6, 4, 5}, the resource in the frequency and time domain corresponding to DRCH (8, 0) is the first in the corresponding TTI. Group 0 of the OFDM symbol, Group 3 of the second OFDM symbol, Group 1 of the third OFDM symbol, Group 7 of the fourth OFDM symbol 7, Group 2 of the fifth OFDM symbol 2, Group 6 of the sixth OFDM symbol, Seventh OFDM symbol A resource included in DRCH (8, 0) is defined by gathering all of the subcarriers included in group 4 of group 4 and group 5 of eighth OFDM symbol.

In more general terms, the above-described content is expressed in a frequency and time domain corresponding to DRCH (8, k) in a base station defined as S = {0, 3, 1, 7, 2, 6, 4, 5}. The resource is equal to ((0 + k)% N, (3 + k)% N, (1 + k)% N, (7 + k)% N, (2 + k)% N, in each OFDM symbol in the TTI). Subcarriers corresponding to the group represented by (6 + k)% N, (4 + k)% N and (5 + k)% N} are obtained. In the above, '%' represents a modulo operation.

Accordingly, the resources in the frequency and time domain corresponding to the DRCH (8, 4) 202 in FIG. 2 are equal to {4% 8, 7% 8, 5% 8, 11% 8, 6 in each OFDM symbol in the TTI. % 8, 10% 8, 8% 8, 9% 8}, that is, the subcarriers included in the group corresponding to {4, 7, 5, 3, 6, 2, 0, 1} are gathered together. .

Another resource allocation unit definition method, LRCH (N, k), refers to a resource corresponding to the k-th group when the time and frequency resources in the TTI are divided into N groups having a localized shape.

3 illustrates an example of allocating resources using the LRCH method in a general OFDMA system.

Referring to FIG. 3, eight OFDM symbols exist in one TTI, and each OFDM symbol may be indicated from L = 0 to L = 7. The one OFDM symbol consists of 32 subcarriers. 32 subcarriers included in the one OFDM symbol are indicated by n = 0 and n = 31.

In FIG. 3, a resource corresponding to LRCH (4, 0) where N = 4 and k = 0 is indicated as 300. 64 subcarriers corresponding to n = 0 to 7 included in eight OFDM symbols in the one TTI constitute an LRCH (4, 0) 300. 64 subcarriers corresponding to n = 8 to 15 included in eight OFDM symbols in the one TTI constitute an LRCH (4, 1) 302. 64 subcarriers corresponding to n = 16 to 23 included in eight OFDM symbols in the one TTI constitute LRCH (4, 2). 64 subcarriers corresponding to n = 24 to 31 included in eight OFDM symbols in the one TTI configure LRCH (4, 3).

The resource indication method using the DRCH and the LRCH may be simultaneously applied to the same time-frequency resource. For example, first, time-frequency resources can be divided into a certain number of DRCHs, and then the remaining resources can be divided into LRCHs. On the contrary, time-frequency resources can be divided into LRCHs and the remaining resources are divided into DRCHs. You can also assign.

4 and 5 are diagrams showing an example of using the DRCH and LRCH at the same time for the same time-frequency resources.

FIG. 4 illustrates that LRCH (4,0) 404 and LRCH (4,1) are allocated by using the remaining resources after DRCH (16,0) 400 and DRCH (16,8) 402 are allocated in a typical OFDMA system. 406, LRCH (4,2) 408, and LRCH (4,3) 410 are examples of resource allocation.

FIG. 5 is a diagram illustrating an example in which the DRCHs 502, 504, and 506 are configured by using the remaining resources after the LRCH (4, 2) 50 is allocated in a typical OFDMA system.

In the above-described OFDM mobile communication system, DRCH and LRCH data channels configured as shown in FIGS. 4 and 5 may be allocated to terminals through a specific data control channel received by all terminals.

For example, the resources allocated to all terminals may be indicated by using a method of repeating the identifier of each terminal and the identifier of DRCH or LRCH resources allocated to the terminal in a common data control channel. This method requires n bits to indicate a specific DRCH and LRCH, and the number of UEs when the size of MCS (Modulation and Coding Scheme) for receiving a data channel is m bits. As many bits must be transmitted through a common data control channel. For example, if the number of terminals is 40, n is 8, and m is 4, a total of 40X (8 + 4), that is, 480 bits of information is transmitted through a common control channel in order to transmit resource allocation information for 40 terminals. shall. However, since a common data control channel must be received from a terminal far from the transmitter, there is a problem in carrying a large amount of information.

The present invention provides a method and apparatus for allocating resources to a plurality of terminals in an orthogonal frequency division multiple access mobile communication system.

A method for a terminal of an orthogonal frequency multiple access type mobile communication system according to the present invention for allocating resources from a base station includes: receiving a plurality of data control channels transmitted using the base station and a specific time-frequency resource; And checking the number of DRCH and LRCH constituting the data channels through the received plurality of data control channels.

A method for allocating resources to at least one terminal by a base station of a mobile communication system of an orthogonal frequency multiple access method according to the present invention includes the data control channel including resource information allocated to a terminal according to a predetermined rule with the terminal. And a step of transmitting the configured data control channel using a specific time-frequency resource.

A method for a terminal of an orthogonal frequency multiple access type mobile communication system according to the present invention for allocating a resource from a base station includes: receiving a main data control channel using the base station and a predetermined time-frequency resource; Acquiring a resource amount of at least one secondary data control channel through a primary data control channel, and corresponding to the terminal in order from a predetermined specific location with the base station using the obtained secondary data control channel; Receiving each of the sub data control channel transmitted by using the resources of the amount of resources, and the process of checking the number of DRCH and LRCH constituting the data channel to the received sub data control channel.

A method for allocating resources to at least one terminal by a base station of a mobile communication system of an orthogonal frequency multiple access method according to the present invention comprises allocating resources to respective sub data control channels in order according to a predetermined rule with the terminal. Specifying a quantity of resources allocated for transmitting each of the at least one secondary data control channel to a primary data control channel, and using different secondary data control channels according to a forward reception capability of the terminal. And transmitting the primary data control channel and the secondary data control channel including the resource information allocated to the terminal.

According to the present invention, a base station apparatus for allocating resources to at least one terminal by a base station of a mobile communication system of an orthogonal frequency multiple access method determines downlink resource allocation information and controls data according to the resource information allocated to the terminal. A downlink scheduler constituting a channel, a symbol generator for generating data symbols of the terminal based on the control information output from the downlink scheduler, a serial / parallel converter for converting the generated data symbols into a parallel signal, A mapper for mapping the parallel-converted signal to a frequency resource allocated to each terminal, an inverse fast Fourier transformer for converting and outputting a signal mapped to the subcarrier into a signal in a time domain, and a signal converted to the time domain And a guard interval inserter for inserting the interval.

According to the present invention, a terminal apparatus for receiving resource allocation from a base station of a mobile communication system of an orthogonal frequency multiple access method includes a guard interval remover for removing a guard interval from a signal received from the base station, and a signal from which the guard interval is removed. A parallel / serial converter converting the parallel signal into a parallel signal, a fast Fourier transformer converting the signal converted into the serial signal into a signal in the frequency domain, a control channel decoder for demodulating control information by receiving control signals from the fast Fourier transformer; And a demapper that receives a signal output from the fast Fourier transformer and extracts data transmitted to a frequency resource corresponding to the terminal based on control information demodulated by the control channel decoder.

DETAILED DESCRIPTION Hereinafter, detailed descriptions of preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the same components in the figures represent the same numerals wherever possible. Specific details are set forth in the following description, which is provided to aid a more general understanding of the invention. 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.

To this end, in a system of orthogonal frequency division multiple access according to an embodiment of the present invention, each base station fixes a number of DRCHs and LRCHs constituting a data channel for a specific period and transmits a common channel (for example, broadcasting). It transmits to all terminals in the base station through a channel (Broadcast Channel).

As such, when the base station configures the DRCH first as shown in FIG. 4 without fixing the number of DRCHs and LRCHs during a specific period, the base station allocates any DRCH resources to all terminals allocating the LRCH in the base station every TTI. The data control channel should be informed whether or not to configure the LRCH.

That is, all resources allocated to the DRCH among time-frequency resources should be indicated one by one in the same manner as in the bitmap. In order to transmit this information, n bits are required to indicate the DRCH, and when the number of allocated DRCHs is m, m X n bits are required and all terminals allocated to the LRCH must be received, and thus, the data must be transmitted with high power. In the present invention, the number of DRCHs and LRCHs is fixedly used during a specific period, thereby reducing the number of information that the base station needs to transmit through the data control channel for every TTI.

In the scheme proposed by the present invention, the UE can receive data transmitted to itself by receiving the common channel transmitted periodically and knowing the number of DRCH and LRCH constituting the data channel transmitted by the base station during a specific period. have.

According to an embodiment of the present invention, the base station may transmit a data control channel for notifying how many time-frequency resources are allocated to which UE during the corresponding TTI. It is obvious that the information can be transmitted through a channel having a similar function in addition to the data control channel.

Meanwhile, in the method proposed in the present invention, in order to reduce the power required to transmit a data control channel, data control is performed by minimizing information that a terminal located far from a base station needs to receive and transmitting the information through a data control channel having a different transmission power. We propose a method for efficient channel transmission.

To this end, the present invention will be described a method of configuring the data control channel using the PDCCH and SDCCH as an embodiment of the method for efficiently configuring the data control channel in the mobile communication system. As described above, in the embodiment of the present invention, a primary data control channel (hereinafter referred to as "PDCCH") and a plurality of secondary data control channels (hereinafter referred to as "SDCCH") are defined.

In an embodiment of the present invention, the primary data control channel is a channel that should be received by all terminals newly allocated to the corresponding TTI in the base station, and should be transmitted at high power to ensure successful reception even to terminals far from the base station. It is transmitted using a fixed time-frequency resource.

Therefore, in order to lower the power required for transmission of the main data control channel, only minimum information should be transmitted. In an embodiment of the present invention, the base station allocates resources to each SDCCH in order using a specific rule, and uses a method of designating and transmitting only the amount of resources allocated to transmitting each of the plurality of SDCCHs in the PDCCH.

For example, assuming that the number of SDCCHs is three and the time-frequency resources used to transmit each SDCCH1, SDCCH2, and SDCCH3 are sequentially allocated from DRCH (160, 0), each SDCCH is a DRCH (160, 0) to DRCH (160 , n ₁ -1), DRCH (160, n ₁ ) to DRCH (160, n ₁ + n ₂ -1), DRCH (160, n ₁ + n ₂ ) to DRCH (160, n ₁ + n ₂ + n When transmitted using ₃ -1), only values of n ₁ , n ₂ , and n ₃ may be included in the PDCCH and transmitted.

In an embodiment of the present invention, the UE receives a PDCCH transmitted using a predetermined time-frequency resource, obtains an amount of resources of each SDCCH transmitted through the PDCCH, and the corresponding amount in order from a specific location in a predetermined order with a base station. Using as many resources, each transmitted SDCCH can be successfully received.

Table 1 below shows the structure of the PDCCH according to an embodiment of the present invention.

Field Bits SDCCH0NumDRCH160 4 SDCCH1NumDRCH160 4 SDCCH2NumDRCH160 4

In Table 1, it is assumed that three SDCCHs exist and resources for transmitting respective SDCCHs are sequentially allocated from DRCHs 160 and 0. The SDCCH0NumDRCH160 field transmitted through the PDCCH below is a field indicating the number of DRCH (160, x) allocated to SDCCH 0, the SDCCH1NumDRCH160 field is a field indicating the number of DRCH (160, x) allocated to SDCCH 1, and an SDCCH2NumDRCH160 field. Is a field indicating the number of DRCH (160, x) allocated to SDCCH 2.

According to the scheme proposed by the present invention, the base station defines a plurality of data control channels and transmits resource information allocated to the corresponding terminal by using different data control channels according to the forward reception capability of the terminal.

For example, if the UE reports the forward reception performance using a channel quality indicator (CQI) and three SDCCHs, that is, SDCCH1, SDCCH2, and SDCCH3 are used in the TTI, the base station reports CQI0 to CQI4. The terminal reporting SDCCH No. 1 and CQI5 to CQI9 may allocate time-frequency resources using SDCCH No. 2 and the terminal reporting CQI10 to CQI14.

In the scheme proposed by the present invention, the terminal selects a data control channel that may include resource allocation information for the terminal from among the plurality of data control channels according to the reported forward reception performance.

In the scheme proposed by the present invention, in order to minimize the amount of information transmitted by using each data control channel, the base station can allocate all resources divided into several parts instead of writing down all the DRCH or LRCH identifiers allocated to a specific UE. List them in a row, and indicate the number of cases (Permutation Index, hereinafter referred to as PI) among the actual allocated shapes, and resource allocation information that indicates which part is allocated to the terminal within the allocated shape. (Hereinafter referred to as RAM).

Table 2 below shows the number of cases when 16 DRCHs are divided according to a defined chunk when there are 16 DRCHs in the embodiment of the present invention.

For example, if you have 16 DRCHs and divide them into a single chunk, the number will be one as shown in the first and second columns of <Table 2> below. The number of cases where the 16 DRCHs are divided into two chunks is 14 as shown in the third and fourth columns of Table 2, and the number of cases where the chunk is divided into three chunks is 105. Thus, the number of bits required to express the combination varies depending on how many 16 resources are divided. For example, four bits are required to represent all 16 resource dividing cases in two, and seven bits are needed to express all three dividing cases with 16 resources.

CI M = 1 CI M = 2 CI M = 3 0 16 0 (1, 15) 0 (1, 1, 14) One (2, 14) One (1, 2, 13) 2 (3, 13) 2 (1, 3, 12) 3 (4, 12) 3 (1, 4, 11) 4 (5, 11) 4 (1, 5, 10) 5 (6, 10) 5 (1, 6, 9) 6 (7, 9) 6 (1, 7, 8) 7 (8, 8) 7 (1, 8, 7) 8 (9, 6) 8 (1, 9, 6) 9 (10, 6) 9 (1, 10, 5) 10 (11, 5) 10 (1, 11, 4) 11 (12, 4) 11 (1, 12, 3) 12 (13, 3) 12 (1, 13, 2) 13 (14, 2) 13 (1, 14, 2) 14 (15, 1) 14 (2, 1, 13) 15 (2, 2, 12) ... ...

In another method proposed by the present invention, in addition to the method of using the number of the above case, the base station may indicate resources by using a tree structure for allocable DRCH or LRCH resources.

6 illustrates an example of allocating 16 resources in an OFDMA mobile communication system according to an embodiment of the present invention. In this figure, the base station allocates resource 0 of resource 16 to terminal 1 and resources 14 and 15 602 and 604 to terminal 2 among 16 resources.

In order to deliver the above-described resource allocation to the terminal, the base station transmits the fact that 16 resources are divided into three according to the method proposed by the present invention through a data control channel, and is capable of dividing 16 resources into three. Transmitting RAM "101" indicating that the first and third resources among the three resource chunks and CI 14 corresponding to the actual divided shapes (2, 1, 13) among 105 cases are transmitted to the terminal. It transmits information of the allocated resources to the terminals receiving the data control channel.

In the scheme proposed by the present invention, a data control channel proposes a method including only allocation information of resources allocable to a data channel by a base station. For example, if the minimum amount of resources allocated by the base station to the data channel is DRCH (40, x), and five DRCH (160, 0) to DRCH (160, 4) is used to transmit the PDCCH and a plurality of SDCCH, It cannot be used for data channels. Therefore, the SDCCH transmits allocation information for 38 resources from DRCH (40, 2) to DRCH (40, 39) except for the resources used to transmit the PDCCH and SDCCH.

Table 3 below is a table showing an embodiment of the structure of the SDCCH proposed in the present invention. The following SDCCH assumes that LRCH and 40 DRCH are used for a UE having a similar forward channel situation. In the SDCCH structure of the following embodiment, LRCH allocation information is first expressed and then DRCH allocation information is included.

Field Bits Numlrch 3 {NumLRCH occurrences MACID 10 LRCHResourceAllocationMaP 8 MCSLevelInd 4 AISN One Supplemental One } NumDRCHBlock 6 PermultationIndex Variable DRCHResourceAllocationMap NumDRCHBlock  {Number of '1's in DRCHResourceAllocationMap occurences MACID 10 MCSLevelInd 4 AISN One Supplemental One LRCHIncluded One LRCHResourceAllocationMap 0 or 8 }

In the <Table 3>, the NumLRCH field is a field indicating the number of UEs to which only LRCHs included in the SDCCHs are allocated, and information on the UEs allocated by the value of this field is included in the SDCCHs. The MACID field is a field indicating an identifier of a terminal to which a resource has been allocated. The LRCHResourceAllocationMap field is an 8-bit bitmap field indicating an LRCH allocated to a corresponding terminal among 8 LRCHs. Indicates whether or not it has been allocated. The MCSLecelInd field is a field indicating demodulation encoding information (MCS) of a packet transmitted through a resource allocated to a corresponding UE. The AISN field represents order information indicating whether a packet transmitted to the allocated resource is the same packet as a packet previously retransmitted. The Supplemental field is a field indicating whether a newly allocated resource is allocated in addition to a previously allocated resource or whether a new amount of resource is allocated by ignoring a previously allocated resource.

After the LRCH resource allocation information, the DRCH resource allocation information is included in the SDCCH and transmitted. The NumDRCHBlock field is a field indicating how many 40 DRCHs are allocated by the SDCCH. The PermutationIndex field is a field indicating that the number of 40 DRCHs divided by NumDRCHBlocks corresponds to the shape of an actually allocated DRCH. The length of the PermutationIndex field depends on the value of the NumDRCHBlock field. The DRCHResourceAllocationMap field is a bitmap indicating which part of the NCHDRCHBlock divided DRCHs is actually allocated to the UE. The DRCHResourceAllocationMap field includes bits as many as the value of the NumDRCHBlock field and indicates whether the nth DRCH part of the DRCH divided by the nth bit is allocated. Indicates. Thereafter, the SDCCH includes the reception terminal information in the SDCCH by the number '1' included in the DRCHResourceAllocationMap field. The MACID, MCSLevelInd, AISN, and Supplemental fields indicating the reception information of the UE are fields having the same meaning as previously used when allocating the LRCH. The LRCHIncluded field is a field indicating whether a terminal allocated with DRCH is also allocated LRCH at the same time. When the terminal has a value of '1', the LRCHResourceAllocationMap field is included.

In the scheme proposed by the present invention, in order to minimize the number of bits transmitted in each data control channel, a UE that transmits a CQI corresponding to the corresponding data control channel may receive all data control channels corresponding to a lower CQI than the CQI. Assume that there is. In addition, in the scheme proposed by the present invention, the base station configures a data control channel corresponding to the lowest CQI level, and the data control channels corresponding to the next CQI level are assigned to the remaining resources except the resources allocated by the lower level data control channel. We propose a scheme to deliver only allocation information for

By using this method it is possible to minimize the number of bits transmitted on each data control channel.

7 to 9 illustrate an example of allocating resources using SDCCH0, SDCCH1, and SDCCH2 when 40, 1, 8, and 3 UEs belong to three CQI groups according to an embodiment of the present invention. The figure shows.

7 is a diagram illustrating an example of allocating resources by using SDCCH0 when there is only one UE belonging to the first CQI group according to an embodiment of the present invention. The first blocks 700 illustrate 40 DRCH resources. Among them, blocks 702 are occupied by retransmission to previously allocated resources and thus cannot be allocated in this TTI, and blocks 704 are regions that can be allocated in this TTI.

The second blocks 706 of FIG. 7 represent resources actually allocated to one terminal, and are areas in which reference numeral 708 is assigned to each terminal. Therefore, SDCCH0 divides 40 resources into three parts and allocates one of them to the UE. The number of bits required for this is assuming that the SDCCH structure shown in Table 3 above includes 3 bits of NumLRCH, 6 bits of NumDRCHBlock, 10 bits of PermutationIndex (number of cases where 40 DRCHs are divided into 3, number of bits required to represent 741), DRCHResourceAllocationMap 3 bits (a field indicating whether the terminals are allocated to each of the three parts. In this example, the value has a value of '010' and the nth bit indicates whether the nth resource is allocated to the terminal through SDCCH0.) MACID 10 bits, MCSLevelInd 4 bits, AISN 1 bit, Supplemental 1 bit, and LRCHIncluded 1 bit will require a total of 39 bits.

8 is a diagram illustrating an example of allocating resources by using SDCCH1 when there are eight UEs belonging to a second CQI group according to an embodiment of the present invention. The first blocks 800 illustrate 40 DRCH resources. Among these, a block like reference number 802 is occupied by retransmission to a previously allocated resource and indicates an area that cannot be allocated in this TTI, and blocks like reference number 804 are areas that are already allocated in SDCCH0 and cannot be used in SDCCH1, A block like reference number 806 indicates an area that can be allocated using SDCCH1 in this TTI.

The second blocks 808 of FIG. 8 represent resources allocated to eight terminals. Blocks 806 are areas allocated to eight terminals, respectively. Therefore, SDCCH1 divides 40 resources into 15 parts and allocates 8 of them to the UEs. The number of bits required for this is assuming that the SDCCH structure in Table 3 shows the number of cases where 36 DRCHs are divided by 15 except for 3 bits NumLRCH, 6 bits NumDRCHBlock, and 32 bits PermutationIndex (4 resources allocated in SDCCH0). 2319959400 The number of bits required to indicate 2319959400, DRCHResourceAllocationMap 15 bits (field indicating whether or not allocated to the terminal for each of the 15 parts in the embodiment of the present invention has a value of '010110101011010', n-th bit is n-th resource is SDCCH1 It indicates whether it is assigned to the terminal through)), the number of terminals is 8 X {MACID 10 bits, MCSLevelInd 4 bits, AISN 1 bit, Supplemental 1 bit, LRCHIncluded 1 bit} and a total of 192 bits are required.

FIG. 9 is a diagram illustrating an example of allocating resources using SDCCH2 when three UEs belong to a third CQI group. According to an embodiment of the present invention, the first blocks 900 represent 40 DRCH resources. Among these, the block 902 indicates an area occupied by retransmission to a previously allocated resource and cannot be allocated in this TTI, and the block 904 is an area which is already allocated in SDCCH0 and cannot be used in SDCCH2. A block 906 is an area which is already allocated in SDCCH1 and cannot be used in SDCCH2, and a block 908 indicates an area that can be allocated using SDCCH2 in this TTI. The second blocks 910 of FIG. 9 represent resources allocated to three terminals, and a block 912 is assigned to three terminals, respectively.

Therefore, SDCCH2 divides 40 resources into six parts and allocates three of them to the UEs. The number of bits required for this is assuming that the SDCCH structure of Table 3 shows that NDRLRCH 3 bits, NumDRCHBlock 6 bits, and PermutationIndex 17 bits (27 DRCHs except for 13 resources allocated by SDCCH0 and SDCCH1 are divided into 6). Number, the number of bits required to indicate 65780), DRCHResourceAllocationMap 6 bits (field indicating whether or not allocated to the terminal for each of the six parts in this example has a value of '010110', where nth bit is the nth resource is SDCCH2 It indicates whether it is allocated to the terminal through), the number of terminals 3 X {MACID 10 bits, MCSLevelInd 4 bits, AISN 1 bit, Supplemental 1 bit, LRCHIncluded 1 bit} is required a total of 83 bits.

10 is a flowchart illustrating a method for allocating resources to at least one terminal by a base station in an orthogonal frequency division multiple access mobile communication system according to an embodiment of the present invention.

In step 1000, the base station defines different sub data control channels (SDCCH) according to the forward reception capability of the terminal, and in step 1010, the base station uses resources corresponding to the sub data control channel (SDCCH) according to a predetermined rule with the terminal. In step 1020, the amount of resources allocated to the secondary data control channel for transmitting at least one secondary data control channel (SDCCH) to the primary data control channel (PDCCH) is specified.

In step 1030, the primary data control channel (PDCCH) and the secondary data control channel including the resource information allocated to the UE are transmitted.

11 is a flowchart illustrating a method for a user equipment to allocate resources from a base station in a mobile communication system using an orthogonal frequency division multiple access according to an embodiment of the present invention.

In step 1100, the UE receives a main data control channel using a predetermined time-frequency resource with the base station, and in step 1110, acquires a resource amount of a sub data control channel through the main data control channel. In step 1120, the UE receives each sub data control channel using the amount of resources corresponding to the UE in a predetermined order with the base station. In step 1130, the UE checks the number of DRCHs and LRCHs constituting the data channel. Receive data from

12 is a block diagram of a base station 1200 for allocating time-frequency resources to at least one terminal in an orthogonal frequency division multiplexing mobile communication system according to an embodiment of the present invention. 12 illustrates the entire structure of a base station 1200 which is a transmitting end in a downlink (forward link). The downlink scheduler 1202 determines downlink resource allocation information and controls information on symbol generation and demodulation of a data channel such as an error coding and modulation method for each terminal, in addition to the resource information allocated to each terminal. It also contains information. The downlink scheduler 1202 may configure a data control channel using the method proposed by the present invention according to resource information allocated to each terminal. The symbol generator 512 for the control channel, the data symbol generator 1206 for the terminal 1, and the data symbol generators 1208 for the terminal N are control information output from the downlink scheduler 1202 as a symbol generator of the data channel. Based on the generated data symbols for each terminal. The symbol generator 512, the data symbol generator 1206 for terminal 1, and the data symbol generator 1208 for terminal N may include blocks such as error correction coding, rate matching, interleaver, symbol modulator, and the like. Since the present invention is not related to the main contents, detailed description thereof will be omitted.

Data symbols generated by the symbol generator 512, the data symbol generator 1206 for the terminal 1, and the data symbol generator 1208 for the terminal N are input to the serial / parallel converter 1210, converted into parallel signals, and then mapped to a mapper. It is input to (Mapper) 1212. The mapper 1212 serves to map data symbols to actual frequency resources allocated to each terminal. The data symbols of all terminals mapped to subcarriers which are actual frequency resources in the mapper 1212 are converted into signals in the time domain in an Inverse Fast Fourier Transfer (hereinafter referred to as "IFFT") 1214. The parallel signal converted into the time domain in the IFFT 1214 is converted into OFDM samples which are serial signals by the parallel / serial converter 1216 and input to the guard interval inserter 1218. The guard interval inserter 1218 is in the form of a cyclic prefix that repeats some of the OFDM samples. The signal with the guard interval inserted by the guard interval inserter 519 is transmitted to the radio channel through the antenna 1220.

13 is a block diagram of a terminal 1300 for receiving resources from the base station 1200 according to an embodiment of the present invention in an orthogonal frequency division multiplexing mobile communication system.

The antenna 1302 receives a signal transmitted from the base station 1200 to the wireless channel, the guard interval remover 1304 removes the guard interval signal inserted in the base station 1200, the protection The serial signal from which the interval signal is removed is output to the serial / parallel converter 1306. A serial / parallel converter 1306 converts the input serial signal in parallel and outputs it to a fast Fourier transformer (FFT) 1308, and the FFT 1308 converts the signal in the time domain into a signal in the frequency domain. do. Control signals among the signals output from the FFT 1308 are input to the control channel decoder 1310, and the control channel decoder 1310 demodulates control information based on the input control signals. The control channel decoder 1310 demodulates the control channel according to the procedure of receiving and interpreting the data control channel as described above. The demapper 1312 receives the output signal of the FFT 1308 and extracts data transmitted through the frequency resource corresponding to the terminal using the control information demodulated by the control channel decoder 1310. The received signal for the corresponding terminal 1300 separated from the demapper 1312 is input to the parallel / serial converter 1314, and the parallel / serial converter 1314 converts the input signal into a serial signal and then data. Output to channel decoder 1316. The data channel decoder 1316 demodulates the signal converted into the serial signal using the control information of the control channel decoder 1310.

In a system using a multiple access scheme based on the frequency division multiplexing scheme, time-frequency resources in a forward direction can be efficiently allocated to a plurality of terminals.

Claims (10)

A method for a terminal of a mobile communication system of an orthogonal frequency multiple access scheme to receive a resource from a base station, Receiving a plurality of data control channels transmitted using the base station and a specific time-frequency resource; And checking the number of DRCH and LRCH constituting the data channels through the received data control channels. According to claim 1, The data control channel, A resource allocation method in an orthogonal frequency multiple access mobile communication system, characterized in that the primary data control channel (PDCCH) and the secondary data control channel (SDCCH). A method for allocating resources to at least one terminal by a base station of a mobile communication system of an orthogonal frequency multiple access method, Configuring the data control channel including resource information allocated to the terminal according to a predetermined rule with the terminal; And a method of transmitting the configured data control channel using a specific time-frequency resource. The method of claim 3, wherein The data control channel, A resource allocation method in an orthogonal frequency multiple access mobile communication system, characterized in that the primary data control channel (PDCCH) and the secondary data control channel (SDCCH). A method for a terminal of a mobile communication system of an orthogonal frequency multiple access scheme to receive a resource from a base station, Receiving a main data control channel using the base station and a predetermined time-frequency resource; Acquiring a resource amount of at least one sub data control channel through the received primary data control channel; Receiving each sub data control channel transmitted by using the resource corresponding to the amount of resources corresponding to the terminal in order from the predetermined specific location with the base station by using the acquired sub data control channel; And checking the number of DRCHs and LRCHs constituting a data channel with the received secondary data control channel. A method for allocating resources to at least one terminal by a base station of a mobile communication system of an orthogonal frequency multiple access method, Defining different sub data control channels according to the forward reception capability of the terminal; Allocating resources using a corresponding sub data control channel according to a predetermined rule with the terminal; Designating an amount of resources allocated to a secondary data control channel for transmitting the at least one secondary data control channel to a primary data control channel; And transmitting the primary data control channel and the secondary data control channel including the resource information allocated to the terminal. The method of claim 6, The process of the base station using different sub data control channels according to the forward reception performance of the terminal, And receiving a channel quality indicator (CQI) reported by the terminal and checking a forward reception performance of the terminal. The method of claim 6, Resource information allocated to the terminal, A resource allocation method in an orthogonal frequency multiplexing mobile communication system, characterized in that the number of cases and resource allocation information. A base station apparatus for allocating resources to at least one terminal by a base station of an orthogonal frequency multiple access mobile communication system, A downlink scheduler for determining downlink resource allocation information and configuring a data control channel according to the resource information allocated to the terminal; A symbol generator for generating a data symbol of the terminal based on the control information output from the downlink scheduler; A serial / parallel converter for converting the generated data symbols into parallel signals; A mapper for mapping the parallel-converted signal to a frequency resource allocated to each terminal; An inverse fast Fourier transformer for converting the signal mapped to the subcarrier into a signal in a time domain and outputting the converted signal; And a guard interval inserter for inserting a guard interval into the signal transformed into the time domain. A terminal apparatus for receiving resource allocation from a base station of a mobile communication system of an orthogonal frequency multiple access method, A guard interval remover for removing the guard interval from the signal received from the base station; A parallel / serial converter converting the signal from which the guard interval is removed into a parallel signal; A fast Fourier transformer for converting the signal converted into the serial signal into a signal in a frequency domain; A control channel decoder for demodulating control information by receiving control signals from the fast Fourier transformer; Orthogonal frequency multiplexing comprising receiving a signal output from the fast Fourier transformer and extracting data transmitted to a frequency resource corresponding to the terminal based on control information demodulated by the control channel decoder Resource allocation device in a partitioned mobile communication system.

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