KR101451984B1 - Method and apparatus for transmitting/receiving a control channel in a broadband wireless commmunication system and method for setting up a control channel candidate - Google Patents

Abstract

A method for transmitting a control channel in a broadband wireless communication system, the method comprising: determining an input value of a hash function by performing an operation according to a subframe number in a terminal identifier; Applying the determined input value to the hash function to determine a vowel-level control channel candidate group; And transmitting the modulated symbol stream through the selected control channel candidate among the control channel candidate groups.

Control channel, hash function, UEID, bit-wise permutation, bit-wise cyclic shift

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method and apparatus for transmitting / receiving a control channel in a broadband wireless communication system, and a method of setting a control channel candidate group for the same. [0002]

The present invention relates to a method and apparatus for transmitting / receiving a control channel in a wireless communication system, and more particularly, to a method and apparatus for transmitting / receiving a downlink control channel in a broadband wireless communication system.

The mobile communication system has evolved into a high-speed and high-quality wireless packet data communication system for providing data service and multimedia service apart from providing initial voice-oriented service. A variety of mobile communication standards such as HSDPA (High Speed Downlink Packet Access), HSUPA (High Speed Uplink Packet Access), 3GPP2 HRPD (High Rate Packet Data) Was developed to support.

Existing third generation wireless packet data communication systems such as HSDPA, HSUPA, and HRPD use technologies such as Adaptive Modulation and Coding (AMC) and Channel Adaptive Scheduling to improve transmission efficiency. With the AMC method, the transmitter can adjust the amount of data to be transmitted according to the channel state. In other words, if the channel state is not good, the amount of data to be transmitted is reduced so that the probability of receiving error is adjusted to a desired level. If the channel state is good, the amount of data to be transmitted is increased so that the probability of receiving error can be effectively transmitted. Using the above-described channel-responsive scheduling resource management method, the transmitter selectively services a user having a good channel state among a plurality of users, thereby increasing the system capacity as compared to providing a channel to a user and providing a service. This increase in capacity is called a so-called multi-user diversity gain. In other words, the ACM method and the channel-responsive scheduling method are based on feedback of partial channel state information from a receiver and apply a proper modulation and coding scheme to a time point determined to be most efficient.

Recently, studies have been actively conducted to convert Code Division Multiple Access (CDMA), which is a multiple access scheme used in second and third generation mobile communication systems, into OFDMA (Orthogonal Frequency Division Multiple Access) in the next generation system. 3GPP and 3GPP2 have begun to standardize on evolutionary systems using OFDMA. It is known that the capacity increase can be expected in the OFDMA system as compared with the CDMA system. One of the various causes of capacity increase in the OFDMA scheme is that frequency domain scheduling can be performed on the frequency axis. As the channel gains the capacity gain by the channel adaptive scheduling method according to the time varying characteristic, the channel gain the capacity gain by using different characteristics according to the frequency.

When the ACM method and the channel responsive scheduling method are implemented, the base station adaptively allocates a given radio resource such as frequency, time, and power according to a channel state of a user. This adaptive allocation state is transmitted to the user through the PDCCH by the base station, and the user recognizes which radio resource is allocated to the user through the PDCCH reception.

The allocation of radio resources includes a downlink resource allocation transmitted from a base station and received by each user terminal, and an uplink resource allocation transmitted by a user terminal and received by a base station. The downlink resource allocation is adaptively performed according to the channel status reported by the user and the information amount of data to be transmitted to the user by the base station. In addition, resources allocated to a user through the PDCCH, data is being transmitted, A transmission scheme such as a scheme announces something. Based on the PDCCH information, the user terminal knows how to allocate the downlink resource to itself and how to receive the signal transmitted through the allocated resource. The uplink resource allocation is adaptively performed based on the channel state reported by the user and the amount of data to be transmitted, and data is transmitted to the allocated resource using a certain transmission scheme in which users are allocated to the user through the PDCCH Tell them to do it. Based on the information of the PDCCH, the user terminal recognizes which transmission scheme should be used if the uplink resource is allocated or allocated to the user.

The downlink control information (DCI) included in the PDCCH for downlink resource allocation is generally as follows.

User Equipment IDentification (UE ID): The UE ID is information for identifying whether or not a signal to be transmitted to the UE exists. In general, since a CRC (Cyclic Redundancy Check) according to a specific UE ID is inserted in the DL control information, if the terminal successfully restores the DL control information, the corresponding control information is recognized as information for the corresponding terminal.

Downlink Resource Block (DL RB) allocation information: If the UE has successfully recovered the DL control information, the DL RB information indicates to which resource block its actual data is transmitted.

Transport Format (TF): TF indicates the modulation and coding scheme of a signal to be transmitted. If AMC is applied, the terminal must know the TF to perform the demodulation and decoding process.

Hybrid Automatic Repeat Request (HARQ) related information: The HARQ transmits to the transmitter whether or not the receiver has successfully received the transmission packet, and if the transmitter successfully transmits another packet and the receiver fails to receive the transmission packet, Is the operation of retransmitting the previous packet. The HARQ related information refers to HARQ related information such as whether the transmission signal is initial transmission or retransmission, HARQ process number or the like. Based on this information, the terminal combines the current reception packet with the previous reception packet to decode or perform a new decoding operation .

In addition, additional information for multi-antenna transmission, additional information for power control, and additional information indicating whether distributed transmission is included in the PDCCH, that is, DCI.

The information included in the PDCCH for uplink resource allocation is generally as follows.

The UE identifier (UE ID)

Uplink Resource Block (UL RB) allocation information: If the UE successfully restores the control information, it recognizes to which resource block to transmit data through the UL RB information.

Transport Format (TF): The terminal must know the applicable TF to generate a transmission signal according to the demodulation and decoding scheme requested by the base station.

Hybrid Automatic Repeat request (HARQ) related information

In addition to this, the uplink reference signal additional information for supporting the uplink spatial multiple access, the additional information indicating whether the channel is distributed or not, .

As the mobile communication system evolves into the broadband OFDMA scheme, the amount of resources to be allocated increases, but the amount of resources used as a unit of allocation does not increase in proportion thereto. Therefore, Can not be avoided.

The terminal should attempt blind decoding in a possible candidate group in order to find out what has been transmitted to itself among the various downlink control channels. Herein, the blind decoding means that the base station can transmit the PDCCH using one of the control channel candidates defined in the control channel candidate group, meaning that the terminal receives the control channel information with no prior information as to which control channel information is to be transmitted do.

1 is a diagram illustrating a method of setting a control channel candidate group in a conventional broadband wireless communication system.

In FIG. 1, a control channel element (CCE) means a unit of a logical channel constituting a PDCCH. The CCE corresponds one-to-one with a set of REs (Resource Elements), which is a unit of a physical channel. The aggregation level (AL) is defined as the number of CCEs constituting the PDCCH. When the PDCCH is configured with N CCEs, the AL is N. In the example of FIG. 1, the vowel levels are AL = 1 (111), AL = 2 (112), AL = 4 .

In the example of FIG. 1, it is assumed that the PDCCH uses one modulation scheme. In this case, as the vowel level decreases, the number of coded bits that can be transmitted decreases. This means that the channel code rate of the PDCCH is reduced. In other words, the lower the vowel level, the more control information can be transmitted by using a small amount of resources, but the terminal can receive successfully only when it is experiencing a good channel state. The higher the vowel level, the more resources are used, while the terminal experiencing poor channel conditions is also able to receive successfully. In order to utilize efficient resources, it is desirable to configure a control channel by lowering the vowel level for a terminal having a good channel state and to configure a control channel by increasing a vowel level for a terminal having a poor channel state.

The number of information bits constituting the DCI may differ depending on the attribute of the control information. For example, in marking resource block allocation information, many bits may be used to increase the degree of freedom, and the number of bits may be reduced instead of lowering the degree of freedom. The number of information bits constituting the DCI varies depending on whether or not to include various additional information. If DCIs are configured with different numbers of bits, they are distinguished by DCI format. Since the UE can not know in which DCI format the PDCCH is transmitted, this is also subject to blind decoding. It is preferable that the PDCCH of the DCI format using a lot of bits is transmitted by increasing the vowel level compared to the PDCCH of the DCI format using a small number of bits.

Referring to FIG. 1, eight CCEs 100 to 107 are given. This is for convenience of description, and the number of CCEs is a value that can be changed from time to time. The number of CCEs that affect the number of CCEs is a static value such as a downlink system bandwidth, a number of base station transmit antennas, a number of downlink ACK / NACK channels for supporting uplink HARQ, and a subframe And control region information in which the value changes every time.

In the example of FIG. 1, there are 120 to 127 PDCCH candidates corresponding to AL = 1 (111). Reference numeral 120 denotes a PDCCH configured with one CCE 0 (100), and reference numeral 127 denotes a PDCCH configured with one CCE 7 (107). The PDCCH candidates corresponding to AL = 2 (112) are 128, 129, and so on. Reference numeral 128 indicates that the PDCCH is composed of two CCEs 0 (100) and 1 (101). The PDCCH candidate corresponding to AL = 4 (113) is 132, and the reference numeral 132 is a PDCCH composed of four CCE 0 (100) to CCE 3 (103). There are 134 PDCCH candidates corresponding to AL = 4 (114), and the PDCCH is configured using 8 CCEs including CCE 0 (100) to CCE 7 (107).

In the example of FIG. 1, the method of constructing PDCCH candidates by collection level is based on a tree structure. And a set of PDCCH candidates consisting of a PDCCH candidate set with AL = 2 at AL = 2 and a set of PDCCH candidates with AL = 2 at AL = 4 and a set of PDCCH candidates with AL = 4 at AL = . For example, reference numeral 132 denotes a PDCCH composed of four CCEs CCE 0 to CCE 3, which is a PDCCH candidate 128 in which CCE 0 and CCE 0 are combined and a PDCCH candidate 129 in which CCE 2 and CCE 3 are combined in AL = 2. According to this tree structure, when the total number of CCEs is N_CCE, the number of PDCCHs that can be configured in the collection level AL is floor (N_CCE / AL). Where floor (x) is a discarding function representing the largest integer less than or equal to x.

If the UE needs to decode all PDCCH candidates, blind decoding should be performed on N_CCE + floor (N_CCE / 2) + floor (N_CCE / 4) + floor (N_CCE / 8) PDCCH candidates. The terminal must perform appropriate transmission and reception operations according to the control information informed by the PDCCH. The terminal must receive the PDCCH transmitted to the terminal before performing the operation. The MS must be designed in consideration of the maximum number of decoding attempts in order to avoid missing the PDCCH transmitted to the MS. As described above, the maximum number of attempts to decode PDCCH increases in proportion to N_CCE. For example, if N_CCE = 32, a total of 60 blind decodings should be performed, 32 times at AL = 1, 16 at AL = 2, 8 at AL = 4, 4 at AL = Considering too much blind decoding, the reception complexity of the terminal will increase and the price will increase. For effective blind decoding management, it is necessary to limit the maximum number of blind decoding attempts. This can be achieved by setting a PDCCH candidate group to be decoded for each terminal. The size of the PDCCH candidate group is determined by the maximum number of blind decoding attempts. When the PDCCH candidate group is restricted for each UE, some UEs will share the same PDCCH candidate. If one user occupies a specific PDCCH candidate, another PDCCH candidate using the CCE belonging to this PDCCH candidate can not be used for PDCCH transmission of another user. Therefore, the PDCCH candidate group needs to be defined appropriately for each user.

The present invention provides a method and apparatus for transmitting / receiving a control channel in a broadband wireless communication system and a method for setting a control channel candidate group therefor.

The present invention also provides a method and apparatus for transmitting and receiving a downlink control channel in a broadband wireless communication system and a method for setting a control channel candidate group for each user.

The present invention also provides a method and apparatus for transmitting and receiving a downlink control channel in a broadband wireless communication system, which can reduce the number of decoding attempts of a terminal, and a method for setting a control channel candidate group therefor.

A method of transmitting a control channel in a broadband wireless communication system according to the present invention includes: determining an input value of a hash function by performing an operation according to a subframe number on a terminal identifier; Applying the determined input value to the hash function to determine a vowel-level control channel candidate group; And transmitting the modulated symbol stream through the selected control channel candidate among the control channel candidate groups.

A method of receiving a control channel in a broadband wireless communication system includes: determining an input value of a hash function by performing an operation according to a subframe number on a terminal identifier; Applying the determined input value to the hash function to determine a vowel-level control channel candidate group; And performing decoding for each control information format receivable for the control channel candidate group.

As described above, according to the present invention, first, no separate signaling is required to define a PDCCH candidate group for each user. Therefore, signaling overhead does not occur.

Second, the PDCCH candidate group changes for each subframe. Therefore, even if a different user shares the same PDCCH candidate group in one subframe and a CCE of the PDCCH candidate is preempted by another user, a problem can be solved in the next subframe even if a specific user can not be scheduled.

Third, the required computation amount of the hash function defining the PDCCH candidate group is very small. In the process of determining X, a simple structure such as bit-wise permutation or cyclic shift is adopted, and the intrinsic function is also defined as a linear function, so that the complexity is very low.

Fourth, the hash function proposed in the present invention is characterized in that the PDCCH candidate group is randomly determined if the UEID is randomly determined. The PDCCH candidate group should be randomly determined in order that the PDCCH candidate group collision between different users has a certain statistical characteristic. In the present invention, since the PDCCH candidate group is determined by operating the bit string of the UE ID, the random characteristic of the UE ID assures the random characteristic of the PDCCH candidate group.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

The present invention provides a method of setting a PDCCH candidate group suitable for each user for efficient blind decoding management. To this end, the PDCCH candidates collide with each other for each user, so that a user preempts a specific PDCCH, thereby reducing the probability of a situation in which another user can not be scheduled. If such a situation occurs, So that the problem does not persist. In this case, the method of externally notifying the PDCCH candidates for each user is not preferable in terms of increasing signaling overhead. Therefore, the present invention proposes a method of setting a PDCCH candidate group using a hash function so that a PDCCH candidate group can be implicitly set. Herein, the implicit method means to set up the PDCCH candidate group so that the BS and the UE can share the PDCCH candidate group according to a certain rule without any signaling, and the external method means that the BS and the UE share PDCCH candidates through separate signaling The PDCCH candidate group is set.

The present invention proposes a hash function for setting a PDCCH candidate group for each terminal. In the method of setting the PDCCH using the hash function, the PDCCH candidate group is designated using the UE ID, which is a unique value for each terminal. Here, the hash function is defined by the vowel level, and a plurality of PDCCH candidates within the vowel level are determined based on the output of the hash function. That is, the present invention proposes a hash function for defining the PDCCH candidate group according to the UE ID and the subframe number for efficient blind decoding management. Some users may share the same PDCCH candidate. We use the subframe number as the input of the hash function to design the hash function so that the PDCCH candidate can be determined differently for each subframe so that this situation does not persist. That is, the input of the hash function is the UE ID, the subframe number, the vowel level, and the number of the PDCCH candidates according to the vowel level.

The hash function proposed by the present invention has the form of Equation (1).

Y = {a * X (UEID, suframe_number) + c} mod m

Where X is a variable determined by the UE ID and the subframe number. The number of cases of X that can be formed by a combination of the UE ID and the subframe number is much larger than the number of PDCCH candidates. The hash function is a function that determines PDCCH candidates using a very large range of inputs. In Equation (1), m represents the number of PDCCH candidates at the corresponding vowel level. When the collection level is AL and the number of CCEs is N_CCE, the number of PDCCH candidates is floor (N_CCE / AL). mod refers to a modular operation where x mod y represents the remainder of dividing x by y. And a and c are the parameters of the hash function, which can be defined differently by the vowel level.

The output Y of the hash function in Equation (1) refers to the number of the first PDCCH candidate selected at the corresponding vowel level. If a plurality of PDCCH candidates are defined at the corresponding vowel level, the remaining PDCCH candidates can be determined using the output Y. [

Equation (2) below shows how N_AL PDCCH candidates are determined in the vowel level AL using Y obtained from Equation (1).

1) mod N_CCE}, for k = 0, ..., ((Y + k *? + 1) AL- ., N_AL - 1

Here, S [k] is a set of CCE numbers constituting the (k + 1) th PDCCH candidate, and the number of elements is AL. The first PDCCH candidate (k = 0) is composed of AL CCEs whose CCE numbers are (Y * AL) to ((Y + 1) * AL-1). That is, Y indicates a method of configuring the first PDCCH candidate. In the process of describing the operation of Equation (2), the mod operation is omitted for the sake of convenience. The second PDCCH candidate is a PDCCH candidate that is separated by? (> 0) based on the first PDCCH candidate. If Δ = 1, the second PDCCH candidate (k = 1) consists of a CCE with a CCE number of ((Y + 1) * AL) to ((Y + 2) * AL-1) These are the next CCEs. If the value of? Is set to a large value, it is separated between the PDCCH candidates. When a PDCCH candidate is consecutively set to the user A on the basis of the characteristic of a vowel structure having a tree structure, some PDCCH candidates may share a CCE belonging to one PDCCH candidate assigned to another user B at a higher vowel level. In this case, if user B preempts the PDCCH candidate of the upper vowel level, the user A can not find a usable PDCCH. To avoid this, it may be necessary to set? Large. For example, in FIG. 1, user A is supposed to use two PDCCH candidates 120 and 121 at AL = 1, and user B is supposed to use 128 PDCCH candidates at AL = 2. When user B preempts 128, CCE 0 (100) and CCE 1 (101) belonging to it are resources that can not be used by other users. However, the user A can not be scheduled because he or she has only been allocated 120 and 121 using them. However, if the PDCCH candidates 120 and 122 are allocated to the user A without allocating successive PDCCH candidates 120 and 121, the user B preempts 128 and the PDCCH candidate 120 can not be used, but the PDCCH candidate 120 can be used.

The hash function proposed in the present invention is composed of two processes. The first step is to determine the variable X by using the UEID and the subframe number. The second step is to determine Y by using the determined Y = f (X) = {a * X + It is the process of obtaining. Here, f (X) corresponding to the second process is called a built-in function to distinguish it from the entire hash function.

In the present invention, two embodiments are proposed as the first process for determining X. The first embodiment utilizes bit-wise permutation and the second embodiment utilizes a bit-wise cyclic shift.

FIG. 2 is a diagram illustrating a method of setting a control channel candidate group in a broadband wireless communication system according to a first embodiment of the present invention. In the first embodiment, bit-wise permutation is used to determine the variable X, Is used.

The permutation pattern generator 204 determines a permutation pattern 206 according to the subframe number 202 in response to a command from the controller 216. [ Where the permutation pattern may be computed by a particular function or may be loaded in a value stored in memory (not shown). By using this permutation pattern, the permutation apparatus 210 performs bit-wise permutation of the UE ID 208 to obtain a variable X 212. Meanwhile, the controller 216 receives the number 214 of the PDCCH candidates or receives parameters for determining the number, and transmits a parameter 218 such as a, c, Δ, and m values to the built-in function 220. The built-in function 220 obtains Y 222 using the variable X 212 and the parameter 218. Here, the output Y of the hash function refers to the number of the first PDCCH candidate selected at the corresponding vowel level. The Hash function 200 in FIG. 2 refers to this overall operation.

FIG. 3 is a diagram illustrating a bit-wise permutation operation 210 of a UE ID 208 in a method of setting a control channel candidate group according to the first embodiment of the present invention.

In FIG. 3, it is assumed that the UEID is composed of a0 to a15 16 bits (300). It is bit-wise permutation to shuffle these 16-bit positions. Reference numeral 302 denotes a result of UEID being mixed through bit-wise permutation. The Permutation pattern 206 indicates how to mix the bits of the UE ID. The feature of the hash function of the first embodiment is that the permutation pattern varies depending on the subframe number. That is, as a result of mixing UEID 16 bits 300, the UE ID 302 mixed is different for each subframe. If the built-in function 22 is applied to the variable X 212 obtained by bit-wise permutation of the UE ID 208, a different Y value can be obtained for each subframe.

FIG. 4 illustrates a method of setting a control channel candidate group in a broadband wireless communication system according to a second embodiment of the present invention. In the second embodiment, a bit-wise cyclic shift shift. Using the UE ID 208 and the subframe number 202, the cyclic shift apparatus 400 bit-wise cyclic shifts the UE ID to obtain a variable X 402. 4, the controller 216 receives the number 214 of PDCCH candidates or receives parameters for determining the number, and transmits a parameter 218 such as a, c, Δ, and m values to the built-in function 220 do. The operation of the cyclic shift device 400 will now be described with reference to Equation (3).

X = cyclic_shift (UEID, shift (subframe_number))

Here, the cyclic_shift function represents a function that bit-wise cyclic shifts UEID by shift. An embodiment of a bit-wise cyclic shift operation is shown in Fig. The result of performing a bit-wise cyclic shift of the UE ID of 16 bits (300) by shift = 4 is (510). In Equation (3), the shift value is determined by the subframe number. How to determine the shift value using the subframe number, i.e., the shift () function, is determined by the controller 216 of FIG. The controller 216 receives the number 214 of PDCCH candidates or receives the parameters for determining the number of the PDCCH candidates 214 and determines a shift () function to be used in the cyclic shift device 400. The built-in function 220 obtains Y 404 using the variable X 402 that is bit-wise cyclic shifted UEID 208. As in the first embodiment, the intrinsic function 220 obtains Y 404 using the parameters 218 determined by the controller 216.

One example of the function shift () used in Equation (3) is shift (x) = q * x. Here, q is a constant determined by the number of bits of the UE ID and the value of m in Equation (1), and an integer that is larger than log2 (m) and is not divided by the prime number of the bit number of the UE ID is selected as the q value. Assuming that the UEID is composed of 16 bits, the following value can be selected as q according to the range of m.

m? 4 ===> q = 3

4 <m? 16 ===> q = 5

16 <m? 64 ===> q = 7

64 <m? 128 ===> q = 9

The shift () function using the above-mentioned q value may be used by defining another function as one embodiment.

Bit-wise cyclic shift is a special example of bit-wise permutation. Therefore, the second embodiment is a special example of the first embodiment.

6 is a flowchart illustrating a method of transmitting a control channel by a base station in a wireless communication system according to the present invention.

The base station firstly determines the priority of the user to be scheduled in step 600. [ In step 602, the DCI and the DCI format of the user to be scheduled in priority order are determined. In step 604, the base station calculates the number of usable CCEs in the corresponding subframe. The number of available CCEs includes a static value such as a downlink system bandwidth, a number of base station transmit antennas, a number of downlink ACK / NACK channels for supporting uplink HARQ, and a control value for each subframe, which is a time unit in which scheduling is performed. (control region) information. In step 606, the number m of PDCCH candidates is determined for each collection level. This value is used in the controller 216 to calculate the parameter of the built-in function 220 or in the built-in function 220 of Equation (1). In step 608, a PDCCH candidate group is determined by applying the hash function proposed in the present invention. Step 608 includes steps 610 and 612. In step 610, the first step of the hash function for calculating the input X of the built-in function 220 by applying cyclic shift or permutation according to the subframe number to the UE ID bit string. The method for obtaining X from the UE ID in step 610 applies permutation according to the first embodiment and cyclic shift according to the second embodiment. In step 612, the built-in function f (x) is performed to obtain Y according to the vowel level. Y is determined, a PDCCH candidate is determined according to Equation (2). In step 614, a PDCCH candidate not occupied by a user having a higher priority is selected. The selected PDCCH candidate is determined to be the PDCCH of the corresponding user, and in step 616, the DCI is mapped to the DCI format and channel-encoded and modulated to the selected PDCCH. In step 618, steps 604 to 616 are repeated for the next priority user to be scheduled to complete the PDCCH of all users to be scheduled. In step 620, the data is multiplexed with the DL data signal and then transmitted.

7 is a flowchart illustrating a method for a terminal to receive a control channel in a wireless communication system according to the present invention.

In step 700, each user terminal determines a DCI format that can be received. The receivable DCI format is preset through upper signaling. In step 702, the number of available CCEs is calculated. 6, the number of available CCEs includes a static value such as a downlink system bandwidth, a number of base station transmit antennas, a number of downlink ACK / NACK channels to support uplink HARQ, And the control region information in which the value is changed for each subframe in which the data is transmitted. Therefore, the terminal must receive and recognize all of the values. In step 704, the PDCCH candidate number m is determined for each vowel level. This value is used in the controller 216 to calculate the parameter of the built-in function 220 or in the built-in function 220 of Equation (1). In step 706, a PDCCH candidate group is determined by applying the hash function proposed in the present invention. In step 706, steps 708 and 710 are performed. In step 708, the first step of the hash function for calculating the input X of the built-in function 220 by applying cyclic shift or permutation according to the subframe number to the UE ID bit string. In step 708, a method for obtaining X from the UE ID is to apply permutation according to the first embodiment and apply cyclic shift according to the second embodiment. In step 710, the built-in function f (x) is performed to obtain Y according to the vowel level. Y is determined, a PDCCH candidate is determined according to Equation (2). In step 712, demodulation is performed for each PDCCH candidate obtained in step 706, and then channel decoding is performed for each DCI format that can be received. In step 714, CRC check is performed to determine whether or not the decoding is successful. If decoding fails, step 712 is repeated for another PDCCH candidate obtained in step 706. If all of the PDCCH candidates are decoded but the decoding fails, it is determined that there is no PDCCH transmitted to the corresponding user. If the PDCCH decoding succeeds in step 714, a transmission / reception operation is performed according to the DCI information transmitted through the PDCCH.

FIG. 8 is a block diagram illustrating a configuration of a base station for transmitting a control channel in a broadband wireless communication system according to the present invention.

In FIG. 8, the BS scheduler 800 determines which user is to be allocated a downlink resource or an uplink resource by transmitting a PDCCH to a user, and prioritizes the downlink resource or the uplink resource. The base station scheduler 800 performs this operation based on the channel status reported by each user. The controller 802 controls the operation of each of the other devices based on the scheduler 800 decision. The determination of the scheduler 800 may be updated according to the determination of the controller 802. [ The process proposed by the present invention is performed in an apparatus 804 for performing a PDCCH hash function. The apparatus receives an instruction from the controller 802, such as a parameter of a built-in function, the number of available CCEs, the number of available PDCCH candidates, and a method of determining X, to determine a PDCCH candidate and returns the value to the controller 802 . The determination of the scheduler 800 is converted to DCI through the controller 802. The DCI signal generator 806 receives the DCI from the controller 802 and generates a DCI signal. This signal is transmitted on the PDCCH selected by the controller 802 among the PDCCH candidate groups determined by the PDCCH hash function unit 804. [ This process is performed in the CCE mapping apparatus 808. Meanwhile, the downlink data signal is multiplexed (814) with the PDCCH signal through the channel encoding and modulation process 812. The downlink signal is transmitted through a transmission process 816.

9 is a block diagram illustrating a configuration of a terminal for receiving a control channel in a broadband wireless communication system according to the present invention.

9, the received signal is converted into a baseband signal through a receiving process 900 and is separated into a data signal and a control signal through a demultiplexer 902. [ The control signals are demultiplexed by the CCE de-mapping device 904 for each PDCCH candidate. The process proposed by the present invention is performed in an apparatus 904 that performs a PDCCH hash function. The device 904 receives PDCCH candidates from the controller 908 in response to an instruction such as a built-in function parameter, the number of available CCEs, the number of available PDCCH candidates, and a method for determining X, . The controller 908 informs the CCE de-mapping device 904 of the PDCCH candidates. Then, the channel decoder / demodulator 906 performs demodulation and decoding for each PDCCH candidate to notify the controller 908 of decoding success. If decoding has failed for a particular PDCCH candidate, the controller 908 causes the other PDCCH candidates to perform processing through the CCE de-mapping 904 and the channel decoder / demodulator 906 (906). Meanwhile, the controller 908 determines whether there is a downlink data signal transmitted to the corresponding user through successful decoding of the PDCCH, and demodulates and decodes the data signal extracted from the demultiplexer 902.

1 is a diagram illustrating a method of setting a control channel candidate group in a conventional broadband wireless communication system,

2 is a diagram illustrating a method of setting a control channel candidate group in a broadband wireless communication system according to a first embodiment of the present invention;

3 is a diagram illustrating an operation for performing bit-wise permutation of a UE ID in a method of setting a control channel candidate group according to a first embodiment of the present invention;

4 is a diagram illustrating a method of setting a control channel candidate group in a broadband wireless communication system according to a second embodiment of the present invention;

5 is a diagram illustrating a bit-wise cyclic shift operation in a method of setting a control channel candidate group according to a second embodiment of the present invention.

6 is a flowchart illustrating a method of transmitting a control channel by a base station in a wireless communication system according to the present invention.

FIG. 7 is a flowchart illustrating a method for a terminal to receive a control channel in a wireless communication system according to the present invention;

8 is a block diagram illustrating a configuration of a base station for transmitting a control channel in a broadband wireless communication system according to the present invention.

9 is a block diagram illustrating a configuration of a terminal for receiving a control channel in a broadband wireless communication system according to the present invention.

Claims (12)

delete A method for transmitting a control channel in a broadband wireless communication system, Determining an input value of a hash function by performing an operation according to a subframe number on a terminal identifier; Applying the determined input value to the hash function to determine a vowel-level control channel candidate group; And And transmitting a modulated symbol stream through the selected control channel candidate among the control channel candidate groups, Wherein the operation is to replace a bit string of the terminal identifier according to the sub frame number and the bit string of the terminal identifier is changed according to the sub frame number by the substitution . A method for transmitting a control channel in a broadband wireless communication system, Determining an input value of a hash function by performing an operation according to a subframe number on a terminal identifier; Applying the determined input value to the hash function to determine a vowel-level control channel candidate group; And And transmitting a modulated symbol stream through the selected control channel candidate among the control channel candidate groups, Wherein the operation is a cyclic transition of a bit string of the terminal identifier according to the subframe number, and the bit stream of the terminal identifier is varied according to the subframe number by the cyclic transition. How to. delete A method for receiving a control channel in a broadband wireless communication system, Determining an input value of a hash function by performing an operation according to a subframe number on a terminal identifier; Applying the determined input value to the hash function to determine a vowel-level control channel candidate group; And And performing decoding for each control information format receivable for the control channel candidate group, Wherein the operation replaces a bit string of the terminal identifier according to the sub frame number and the bit string of the terminal identifier is changed according to the sub frame number. . A method for receiving a control channel in a broadband wireless communication system, Determining an input value of a hash function by performing an operation according to a subframe number on a terminal identifier; Applying the determined input value to the hash function to determine a vowel-level control channel candidate group; And And performing decoding for each control information format receivable for the control channel candidate group, Wherein the operation is a cyclic transition of a bit string of the terminal identifier according to the sub frame number and the bit string of the terminal identifier is varied according to the sub frame number by the cyclic transition, How to. delete An apparatus for transmitting a control channel in a broadband wireless communication system, A control unit for determining an input value of a hash function by performing an operation according to a subframe number in a terminal identifier and determining a candidate group for each collection level by applying the determined input value to the hash function; And a transmitting / receiving unit for transmitting the modulated symbol stream through the selected control channel candidate among the control channel candidate groups, Wherein the operation is to replace a bit string of the terminal identifier according to the sub frame number and the bit string of the terminal identifier is changed according to the sub frame number. . An apparatus for transmitting a control channel in a broadband wireless communication system, A control unit for determining an input value of a hash function by performing an operation according to a subframe number in a terminal identifier and determining a candidate group for each collection level by applying the determined input value to the hash function; And a transmitting / receiving unit for transmitting the modulated symbol stream through the selected control channel candidate among the control channel candidate groups, Wherein the operation is a cyclic transition of a bit string of the terminal identifier according to the subframe number, and the bit stream of the terminal identifier is varied according to the subframe number by the cyclic transition. . delete An apparatus for receiving a control channel in a broadband wireless communication system, A control unit for determining an input value of a hash function by performing an operation according to a subframe number in a terminal identifier and determining a candidate group for each collection level by applying the determined input value to the hash function; And a decoding unit for performing decoding on the control channel candidate groups according to control information formats receivable, Wherein the operation is to replace the bit stream of the terminal identifier according to the sub frame number and the bit stream of the terminal identifier is changed according to the sub frame number. . An apparatus for receiving a control channel in a broadband wireless communication system, A control unit for determining an input value of a hash function by performing an operation according to a subframe number in a terminal identifier and determining a candidate group for each collection level by applying the determined input value to the hash function; And a decoding unit for performing decoding on the control channel candidate groups according to control information formats receivable, Wherein the operation is a cyclic transition of a bit string of the terminal identifier according to the sub frame number and the bit string of the terminal identifier is varied according to the sub frame number by the cyclic transition, .

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