WO2008133415A1 - Méthode de transmission d'un canal de contrôle de liaison descendante dans un système de communication mobile et méthode de mise en correspondance du canal de contrôle avec des ressources physiques en utilisant un entrelaceur de blocs dans un système de communication mobile - Google Patents

Méthode de transmission d'un canal de contrôle de liaison descendante dans un système de communication mobile et méthode de mise en correspondance du canal de contrôle avec des ressources physiques en utilisant un entrelaceur de blocs dans un système de communication mobile Download PDF

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Publication number
WO2008133415A1
WO2008133415A1 PCT/KR2008/002093 KR2008002093W WO2008133415A1 WO 2008133415 A1 WO2008133415 A1 WO 2008133415A1 KR 2008002093 W KR2008002093 W KR 2008002093W WO 2008133415 A1 WO2008133415 A1 WO 2008133415A1
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WO
WIPO (PCT)
Prior art keywords
cce
block interleaver
cell
column
cces
Prior art date
Application number
PCT/KR2008/002093
Other languages
English (en)
Inventor
So Yeon Kim
Young Woo Yun
Ki Jun Kim
Moon Il Lee
Hyun Soo Ko
Jae Hoon Chung
Ji Ae Seok
Seung Hyun Kang
Suk Hyon Yoon
Joon Kui Ahn
Original Assignee
Lg Electronics Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from KR1020070123603A external-priority patent/KR20080096350A/ko
Priority claimed from KR1020070123605A external-priority patent/KR20080096351A/ko
Priority claimed from KR1020080002201A external-priority patent/KR20080096356A/ko
Application filed by Lg Electronics Inc. filed Critical Lg Electronics Inc.
Priority to US12/451,093 priority Critical patent/US8254245B2/en
Priority to BRPI0810979-6A priority patent/BRPI0810979A2/pt
Priority to GB0919205A priority patent/GB2461464B/en
Priority to JP2010506038A priority patent/JP4976543B2/ja
Publication of WO2008133415A1 publication Critical patent/WO2008133415A1/fr
Priority to US13/554,914 priority patent/US8638654B2/en
Priority to US13/928,148 priority patent/US9055580B2/en
Priority to US14/106,239 priority patent/US9049710B2/en
Priority to US14/703,437 priority patent/US9414376B2/en
Priority to US15/207,257 priority patent/US9609645B2/en
Priority to US15/437,659 priority patent/US10142979B2/en
Priority to US16/158,671 priority patent/US10582487B2/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
    • H04L1/0056—Systems characterized by the type of code used
    • H04L1/0071—Use of interleaving
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/1607—Details of the supervisory signal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0053—Allocation of signaling, i.e. of overhead other than pilot signals

Definitions

  • the present disclosure relates to a mobile communication system, and more particularly, to a method for transmitting a downlink control channel in a mobile communication system and a method for mapping the control channel to physical resources using a block interleaver.
  • uplink/downlink data packets are transmitted in units of subframes, each of which is defined as a specific time interval including multiple OFDM symbols.
  • multiple terminals can communicate through one base station and wireless resources are allocated through scheduling of the respective terminals.
  • Uplink/downlink communication of a terminal is performed through the resources allocated in subframes.
  • the control information includes various pieces of information required to transmit and receive uplink/downlink data packets such as wireless resource information, coding methods, and modulation methods used for transmitting and receiving uplink/downlink data packets.
  • Resources are allocated to all or part of multiple OFDM symbols included in one subframe for transmitting such various pieces of control information as well as for transmitting data packets.
  • the control information is transmitted through the allocated resources in the subframe.
  • the base station maps corresponding information bits to wireless resources to transmit the information bits to the terminals.
  • mapping wireless resources to control channels for terminals so that the control channels are uniformly distributed and transmitted over the allocated wireless resources advantageously achieves diversity effects since pieces of control information of a number of terminals can be transmitted together in downlink.
  • a method for mapping the virtual resource units to actual physical resources should be provided to perform actual transmission.
  • the present invention has been made in view of the above circumstances in the background art, and it is an object of the present invention to provide a method for transmitting downlink control channels in a mobile communication system. Another object of the present invention is to provide a method for mapping control channels to physical resources using a block interleaver in a mobile communication system.
  • the above objects can be accomplished by providing a method for transmitting a control channel in a mobile communication system, the method including modulating information bits to generate a plurality of modulated symbols according to a specific modulation scheme, interleaving the plurality of modulated symbols using a block interleaver in units of modulated symbol groups, each including a plurality of continuous modulated symbols, mapping a plurality of modulated symbol groups to resource elements allocated for transmission of at least one control channel in a subframe, and transmitting the at least one control channel, wherein the interleaving includes inputting the plurality of modulated symbol groups row by row to the block interleaver, performing inter-column permutation on the plurality of modulated symbol groups based on a specific permutation pattern, and outputting the plurality of modulated symbol groups column by column from the block interleaver.
  • the size of the block interleaver may be determined according to the number of the plurality of modulated symbol groups transmitted in the subframe.
  • the number of rows of the block interleaver may be determined based on a predetermined number of columns of the block interleaver and the number of the plurality of modulated symbol groups transmitted in the subframe.
  • Each modulated symbol group may be mapped to a resource element group having a plurality of resource elements, the number of resource elements in each resource element group being identical to the number of modulated symbols in each modulated symbol group.
  • the number of modulated symbols in each modulated symbol group and the number of resource elements in each resource element group may be determined according to the number of transmission antennas or spatial multiplexing rate.
  • the plurality of modulated symbol groups may be cyclically shifted using a cell-specific value.
  • the plurality of modulated symbol groups may be mapped to the resource elements excluding resource elements allocated for at least one of a reference signal, an ACK/NACK signal, and a Control Channel Format Indicator (CCFI).
  • CCFI Control Channel Format Indicator
  • the plurality of modulated symbol groups may be mapped to the resource elements according to a time-first mapping scheme.
  • the method may further include at least one of scrambling the information bits for the control channel prior to the modulating, mapping the plurality of modulated symbols to layers, the number of which is equal to or less than the number of transmission antennas of the mobile communication system, and precoding the plurality of modulated symbols for each layer.
  • the control channel may be transmitted using one or more Control Channel Elements (CCEs), each including at least one of the plurality of modulated symbols.
  • CCEs Control Channel Elements
  • FIG. 1 illustrates an example of a procedure in which a transmitting end processes a signal to transmit a specific channel in a mobile communication system.
  • FIGs. 2(a) and 2(b) illustrate two examples of a method for mapping to a physical RE after performing interleaving using a block interleaver according to an embodiment of the invention.
  • FIGs. 3 (a) and 3(b) illustrate detailed examples of a block interleaver applicable to an embodiment of the invention wherein the block interleaver operates with different input and output directions.
  • FIGs. 4(a) and 4(b) illustrate how a permutation operation is performed in the method of interleaving using a block interleaver according to an embodiment of the invention.
  • FIGs. 5(a) and 5(b) illustrate example methods for performing intra-column permutation or intra-row permutation using a block interleaver according to an embodiment of the invention.
  • FIGs. 6(a) and 6(b) illustrate an example method for mapping a symbol sequence output from the block interleaver to physical resource elements according to the embodiment of the invention.
  • FIG. 7 illustrates a mapping relation between virtual and physical resources in an
  • FIGs. 8(a) and 8(b) illustrate example methods for determining a block interleaver size according to an embodiment of the invention.
  • FIG. 9 illustrates an example multiplexing method which can implement interleaving using a block interleaver according to an embodiment of the invention.
  • FIG. 10 illustrates a specification table provided to explain methods of operating a block interleaver according to an embodiment of the invention.
  • FIG. 1 l(a) and 1 l(b) illustrate a shift operation in an interleaving operation method using a block interleaver according to an embodiment of the invention.
  • FIGs. 12(a) and 12(e) illustrate an example method for mapping a control channel interleaved using a block interleaver according to an embodiment of the invention.
  • FIGs. 13(a) to 13(d) illustrate another example method for mapping an interleaved control channel using a block interleaver according to the embodiment of the invention.
  • FIG. 14 illustrates an example where a block interleaver operates according to Mathematical Expression 11.
  • FIG. 15 illustrates an example where a block interleaver operates according to Mathematical Expression 12.
  • FIGs. 16(a) and 16(b) illustrate a method for defining a specific group including all or part of one or more CCEs according to an embodiment of the invention.
  • FIGs. 17(a) and 17(b) illustrate the method for mapping to an OFDM symbol for transmitting a control channel using groups defined according to an embodiment of the invention.
  • FIG. 18 illustrates another method for defining a group including all or part of one or more CCEs according to an embodiment of the invention.
  • FIG. 19 illustrates a method for performing mapping using a group definition method according to an embodiment of the invention.
  • FIG. 20 illustrates an example method for performing mapping using a group definition method according to an embodiment of the invention.
  • FIG. 21 illustrates an example method using the CCE level grouping scheme according to an embodiment of the invention.
  • FIG. 22 illustrates another example method using the CCE level grouping scheme according to an embodiment of the invention.
  • FIG. 23 illustrates an example method for performing mapping using a group definition method according to an embodiment of the invention.
  • FIG. 24 illustrates an example method using the CCE sub-block level grouping scheme according to an embodiment of the invention.
  • FIG. 25 illustrates another example method using the CCE sub-block level grouping scheme according to an embodiment of the invention.
  • FIG. 26 illustrates a method for performing mapping using a group definition method according to an embodiment of the invention.
  • FIG. 27 illustrates an example method for performing mapping using a group definition method according to an embodiment of the invention.
  • FIG. 28 illustrates an example method for performing mapping using a group definition method according to an embodiment of the invention.
  • FIG. 29 illustrates an example configuration of a block interleaver that implements the CCE-to-RE mapping method according to an embodiment of the invention.
  • FIG. 30(a) and 30(b) illustrate example configurations of a block interleaver that implements the CCE-to-RE mapping method according to an embodiment of the invention.
  • FIG. 31 illustrates an example method for performing control channel mapping using a block interleaver according to an embodiment of the invention.
  • FIGs. 32 and 33 illustrate, in a stepwise manner, example operations of a block interleaver constructed according to an embodiment of the invention.
  • FIG. 34 is a flow diagram sequentially illustrating CCE-to-RE mapping processes according to an embodiment of the invention.
  • FIG. 35 illustrates an example method for performing mapping after interleaving is done for each OFDM symbol according to an embodiment of the invention.
  • FIG. 36 illustrates an example method for transmitting different types of control channels according to an embodiment of the invention.
  • FIGs. 37(a) to 37(c) illustrate an example method for allocating mini-CCEs of a PHICH transmitted through each OFDM symbol when interleaving is performed on the PHICH for each OFDM symbol according to an embodiment of the invention.
  • FIG. 38 illustrates an example method for transmitting two or more different types of control channels by performing interleaving on the different types of control channels together for each OFDM symbol according to an embodiment of the invention.
  • FIG. 39 illustrates another example method for transmitting two or more different types of control channels by performing interleaving on the different types of control channels together for each OFDM symbol according to an embodiment of the invention.
  • FIG. 40 illustrates an example method for performing interleaving for each OFDM symbol using a block interleaver according to an embodiment of the invention.
  • FIG. 41 illustrates an example method in which two or more control channels are interleaved together and are then multiplexed and transmitted according to an embodiment of the invention.
  • FIG. 1 illustrates an example procedure in which a transmitting end processes a signal to transmit a specific channel in a mobile communication system.
  • the transmitting end in the mobile communication system performs scrambling 10a and 10b for each codeword generated after the information bit sequence is coded.
  • Scrambling is an operation for mixing bits in a coded information bit sequence using an arbitrary rule (i.e., in an arbitrary order). This operation may be performed using a specific scrambling sequence.
  • Modulation operations 11 (a) and ll(b) are performed for the codewords according to a specific modulation scheme to construct modulated symbols, respectively.
  • modulation scheme examples include BPSK, QPSK, 8PSK, 8QAM, 16QAM, and 64QAM.
  • Modulated symbols generated after modulation can be represented by a complex number such as (x+jy).
  • Layer mapping (12) is performed to map the modulated symbol sequence generated for each codeword to layers.
  • the number of the layers may be less than or equal to the number of transmit antennas of the mobile communication system and can be adaptively set, for example taking into consideration feedback information received from a receiving end, according to communication environments or states.
  • each codeword can be mapped to one or more layers.
  • layer mapping can be performed taking into consideration spatial multiplexing or transmit diversity effects.
  • Precoding (13) can be performed after layer mapping is done. Precoding is an operation for mapping a transmission vector generated for each layer to resources of each transmit antenna. In the multiple antenna system, multiple transmit antennas can be used more effectively through a specific precoding scheme.
  • precoding schemes can be applied taking into consideration spatial multiplexing or transmit diversity effects.
  • a codebook including a plurality of precoding matrix indices can be used to easily select a precoding matrix used for precoding.
  • the modulated symbol sequences output for the transmit antennas through precoding in this manner are mapped to respective resource elements of the transmit antennas 14a and 14b.
  • the present disclosure provides a method for mapping a modulated symbol sequence for a specific channel to physical resources in a mobile communication system.
  • the specific channel may include a variety of transport channels such as a control channel that can be defined in a mobile communication system. More specifically, the present disclosure provides a method for mapping modulated symbols of a control channel to physical resources allocated to one subframe such that resources of one terminal can be uniformly distributed over the transmission band.
  • each RE can be directly defined as a combination of an OFDM symbol in the time domain and a subcarrier in the frequency domain in examples of an OFDM communication system. Mapping to REs can be performed on the basis of a predetermined number of REs.
  • An RB can be defined as a combination of multiple continuous OFDM symbols and multiple continuous subcarriers in examples of an OFDM communication system.
  • the size of an RB can be determined variably according to the type of a cyclic prefix or a system, a frame structure, and the like.
  • a virtual resource block which has the same size as a physical resource block and can be mapped to a physical resource block, can be defined and used as a resource block.
  • a base station can more efficiently schedule communication resources through a logical resource concept of the virtual resource block.
  • a Resource Element Group including a number of REs can be defined.
  • Mapping of REGs can be applied in the same manner as mapping of REs. For example, when multiple antenna transmit diversity such as Space Frequency Block Coding (SFBC) is applied, it is possible to take into consideration mapping to REs corresponding to the same number of consecutive subcarriers as the number of transmit antennas according to a multiple antenna transmission scheme.
  • SFBC Space Frequency Block Coding
  • one RE can be considered one REG including only one subcarrier. Accordingly, mapping according to the above or following embodiments can be applied to REGs, each including multiple REs according to the number of transmit antennas or a spatial multiplexing rate.
  • a modulated symbol sequence mapped to REs is converted into signals in the time domain (for example, OFDM signals), which are then transmitted through respective transmit antennas.
  • interleaving can be performed using a block interleaver before mapping to physical resources.
  • Interleaving can be performed through the block interleaver using random interleaving or a specific permutation pattern interleaving. Due to structural characteristics of the block interleaver, interleaving effects can be obtained using a simple operation according to input and output directions (row-wise or column-wise), in which a symbol sequence is input (written) and output (read) to and from the interleaver, and permutation-related direction.
  • a cyclic shift operation can be additionally performed using cell-specific information such as a cell ID as a shift factor to add cell-specific elements in order to minimize inter-cell interference even when the interleaver is commonly used for multiple cells.
  • FIGs. 2(a) and 2(b) illustrate two examples of a method for mapping to a physical RE after performing interleaving using a block interleaver according to an embodiment of the invention.
  • FIG. 2(a) illustrates an exemplary mapping method of Type 1 that is defined as the case where the direction of input to the block interleaver is a row direction (row- wise).
  • modulated symbols in the modulated symbol sequence produced by performing processing such as coding and modulation on information bits for transmission in a subframe are sequentially input (i.e., written) row-wise (i.e., row by row) to the block interleaver as assumed above.
  • the modulated symbols be grouped into modulated symbol groups and then the modulated symbol sequence be input in units of modulated symbol groups to the interleaver.
  • the modulated symbol sequence is input in units of modulated symbols to the interleaver and the subsequent operations are performed in units of modulated symbols.
  • the block interleaver can perform interleaving such as inter- column interleaving on modulated symbols input row-wise to the block interleaver.
  • the block interleaver can perform intra-column permutation or inter- column permutation.
  • the intra-column permutation or inter-column permutation can be performed using a random pattern or a specific permutation pattern.
  • the permutation pattern can be generated using cell-specific information taking into consideration inter-cell interference.
  • step S32 shift operation can be additionally performed on the modulated symbols on which the intra-column permutation was performed at step S32.
  • cell-specific information can be used as a shift factor for determining a shift offset.
  • step S32 can be performed in the order as shown in FIG. 2(a) and 2(b).
  • the shift operation can be performed on a modulated symbol sequence output (i.e., read) from the block interleaver so that the shifted symbol sequence can be mapped to physical resources.
  • shifting may be performed using a cell-specific value, thereby reducing inter-cell interference.
  • this operation can be removed from the operations of the invention.
  • the block interleaver outputs the modulated symbols after performing random interleaving and shifting thereupon.
  • the block interleaver outputs symbols in a column-wise manner opposite to the manner in which they were input to the block interleaver. Then, at step S34, the output symbol sequence is mapped to physical REs allocated for control channel transmission included in a subframe and the mapped sequence is then transmitted to one or more terminals.
  • interleaving is performed using a block interleaver which is common for multiple cells and cyclic shift is performed on the modulated symbol sequence output from the block interleaver using cell-specific information, thereby reducing system complexity and the amount of signaling information while reducing inter-cell interference.
  • FIG. 2(b) illustrates an exemplary mapping method of Type 2 that is defined as the case where the direction of input to the block interleaver is a column direction (column- wise).
  • the difference between the method of FIG. 2(b) and that of FIG. 2(a) is that the modulated symbol sequence produced by performing processing such as coding and modulation on information bits for transmission in a subframe is sequentially input (i.e., written) to the block interleaver column-wise (column by column) rather than row-wise as assumed above at step S35, permutation is performed row by row at step S36, and the modulated symbols are output (i.e., read) row- wise (i.e., row by row) from the block interleaver at step S38.
  • mapping at steps S34 and S39 in FIGs. 2(a) and 2(b) can be implemented using a frequency (subcarrier)-first mapping scheme or a time (OFDM symbol)-first mapping scheme or a mapping scheme in which the two schemes are applied in units of Physical Resource Blocks (PRBs) in the time/frequency resource regions.
  • PRBs Physical Resource Blocks
  • the size of the block interleaver can be determined using a variety of methods. For example, for ease of use of the block interleaver, either the row or column size of the block interleaver can be fixed and the other can be determined to be variable according to the amount of information. For example, when a block interleaver is used in mapping for control channel transmission, the column size of the block interleaver is fixed and the row size can be varied according to the number of REs or the number of modulated symbols corresponding to a control channel transmitted in a subframe.
  • the degree of freedom of the size of the block interleaver can be increased by additionally performing processes of adding dummy elements to modulated symbols when the symbols are input to the block interleaver and pruning the dummy elements when the modulated symbols are output from the block interleaver.
  • mapping can be performed taking into consideration the number of REs excluding the resources allocated for different channel transmission.
  • mapping can be carried out by performing interleaving on a plurality of channels together.
  • the number of REs which can be used for control channel transmission in OFDM symbols used for downlink control channel transmission through a subframe, may exclude the number of REs used for transmission of a Reference Signal (RS), a Physical Control Format Indication Channel (PCFICH) carrying a Control Channel Format Indicator (CCFI) which is information regarding a control channel transport format, a Paging Indicator Channel (PICH) or a Physical Hybrid- ARQ Indicator Channel (PHICH) carrying downlink (DL) ACK/NACK, and the like in the OFDM symbols.
  • FIGs. 3(a) and 3(b) illustrate detailed examples of a block interleaver applicable to an embodiment of the invention wherein the block interleaver operates with different input and output directions.
  • "R” denotes the number of rows
  • C" denotes the number of columns.
  • FIG. 3(b) illustrates input and output operations of the block interleaver when modulated symbols are input in a column direction (column-wise) to the block interleaver. Since modulated symbols are input column-wise, they will be output row- wise according to the embodiment as shown in FIG. 3 (a). That is, a modulated symbol sequence can be input to the block interleaver sequentially from 1st to Cth columns of the block interleaver or in any order of columns. After interleaving is performed, modulated symbols can be output from the block interleaver sequentially from 1 st to R rows of the block interleaver or in any order.
  • the order of elements before they are input to the block interleaver and the order of elements that are output from the block interleaver can be changed (or can be made different) through the simple method of using different input and output directions of the block interleaver in this manner.
  • Using the block interleaver with different input and output directions in the above manner allows channel elements to be distributed and transmitted uniformly over resources.
  • FIGs. 4(a) and 4(b) illustrate how a permutation operation is performed in the method of interleaving using a block interleaver according to an embodiment of the invention.
  • the inter- column permutation or inter-row permutation operation according to the embodiment can be performed by replacing all modulated symbols in a row or column in the block interleaver with those of another row or column.
  • Inter-row permutation or inter-column permutation is an operation for changing the order of columns or rows to be output from the interleaver before the interleaver outputs the modulated symbols. This operation can change the order of columns or rows to be mapped to physical REs after the interleaver outputs modulated symbols.
  • diversity or randomness can be increased if the inter-column permutation operation is performed when the input direction is a row direction and the output direction is a column direction as shown in FIG. 4(a) and the inter-row permutation operation is performed when the input direction is a column direction and can be increased if the output direction is a row direction as shown in FIG. 4(b).
  • the influence of inter-cell interference can also be reduced by performing an inter-column permutation operation using a specific pattern commonly used for each cell and an operation such as cyclic shift using a cell-specific factor.
  • FIGs. 5(a) and 5(b) illustrate example methods for performing intra-column permutation or intra-row permutation using a block interleaver according to an embodiment of the invention.
  • FIG. 5 (a) illustrates how intra-column permutation is performed using a block interleaver. This method is more effective when the input direction of the block interleaver is a row direction.
  • One specific example of the method of intra-column permutation in the block interleaver is intra-column random reordering. That is, 0 th column random reordering is performed on interleaver elements included in a first column of the block interleaver and 1 st column random reordering is performed on interleaver elements included in a second column of the block interleaver.
  • 2 nd column random reordering is performed on interleaver elements included in a third column of the block interleaver and c-l th column random reordering is performed on interleaver elements included in a Cth column of the block interleaver.
  • the intra-column random reordering operation can be implemented by performing a random reordering process in which row positions of elements of each column are replaced with row positions corresponding to the generated random numbers through random number generation or allocation.
  • the random reordering operation can be implemented as a detailed method in which, when a random pattern for interleaving is obtained, the random pattern is stored as a lookup table in a storage medium and the lookup table is used to smoothly perform random interleaving and de- interleaving.
  • r and c are variables representing row and column indices of an element of the block interleaver to which an interleaver element has been mapped or from which an interleaver element will be pruned before the intra- column reordering operation is performed
  • r' and c' are variables representing row and column indices of an element of the block interleaver to which an interleaver element has been mapped or from which an interleaver element will be pruned after the intra- column reordering operation is performed.
  • Mathematical Expression 1 an operation for generating a unique reordering pattern of each column is defined as a function RR(r, c). Any specific operation method for generating a unique reordering pattern of each column can be represented by the function RR(r, c).
  • Mathematical Expression 2 represents an example of the function RR(r, c).
  • a function CH(r, c) defines hopping of a block interleaver element of a row index r (i.e., a row having index r) in a column index c (i.e., a column having index c) to an element corresponding to a unique value within a range of R elements in a column vector using the two (row and column) indices.
  • a function CO(c) defines addition of a different offset to all elements of each column index c.
  • a variety of operation methods can be represented using the function CH(r, c) and CO(c).
  • Mathematical Expression 3 and Mathematical Expression 4 represent detailed examples of the functions CH(r, c) and CO(c) and the function RR(r, r) specified by these two functions.
  • P represents the difference between an R value finally determined when the number of rows of the block interleaver is determined to be a prime number and an R value determined without taking into consideration the prime number.
  • a random number may be generated within a range having a row size of R so as to satisfy a mapping requirement of the frequency domain that modulated symbols of a specific channel of a terminal be distributed and transmitted over a total system bandwidth and also to satisfy a mapping requirement of the time domain that modulated symbols of a specific channel of a terminal be transmitted uniformly using n OFDM symbols used for transmission.
  • the first OFDM symbol may include a CCE to which none of the modulated symbols of a control channel for a single terminal can be mapped according to a cell-specific shift value since the number of REs available for PDCCH transmission in the first OFDM symbol is small.
  • a random pattern of each column and a random pattern of a previous column can be compared and a random number distance associated with random numbers generated in each column of a block interleaver for the modulated symbols of a specific channel of a terminal can be determined to be less than the number of interleaver elements that can be mapped to the first OFDM symbol.
  • the random number distance can be defined as the difference between the position index of a specific column of a block interleaver for the modulated symbols of a control channel of a specific terminal and the position index of a column subsequent to the specific column.
  • Another specific example of the method of intra-column permutation in the block interleaver is intra-column permutation (column-wise permutation) using a specific permutation pattern.
  • This method can be implemented through a specific permutation pattern based on row and column indices of a resource element group that has been input to the block interleaver.
  • a permutation pattern applied to each column it is preferable that a permutation pattern applied to each column be uniquely constructed for each column. This enables implementation of intra-column (column-wise) permutation patterns with a very low correlation therebetween.
  • the basic operating structure is similar to that of the random interleaving of FIG. 5 with the only difference being that notations "ith-column random reordering" and “ith-row random reordering” can be replaced with “ith-column-wise permutation” and "ith-row-wise permutation”.
  • "i” represents an index of each row or column when interleaving is performed row by row or column by column.
  • the embodiment of the permutation pattern can be represented by the following Table 1.
  • n 2 (sequence length is 72)
  • sequence indices can be sequentially allocated to symbols in the modulated symbol sequence before interleaving in the order in which the symbols are input to the interleaver (i.e., allocated sequentially in the row direction in which the modulated symbols are input to the block interleaver).
  • sequence indices of symbols in a modulated symbol sequence before interleaving can be referred to as input sequence indices. That is, the index of an element of 1st row and 1st column is determined to be 0, the index of an element of 1st row and 2nd column is determined to be 1 , and the index of an element of 1 st row and 3rd column is determined to be 2. After indices of all elements of the 1st row are determined, the next index can be allocated to an element of 2nd row and 1st column. Remaining block interleaver elements can be sequentially analyzed using the same method.
  • sequence indices can be sequentially allocated to symbols in the modulated symbol sequence after interleaving in the order in which the symbols are output from the interleaver (i.e., sequentially allocated in the column direction in which the modulated symbols are output from the block interleaver).
  • the sequence indices of the symbols in the modulated symbol sequence after interleaving are denoted by numbers in Table 1.
  • the sequence indices of symbols in the modulated symbol sequence after interleaving can be referred to as output sequence indices. That is, the index of an element of 1st row and 1st column is determined to be 0, the index of an element of 2nd row and 1st column is determined to be 1, and the index of an element of 3rd row and 1st column is determined to be 2. After indices of all elements of the 1 st column are determined, the next index can be allocated to an element of 1 st row and 2nd column. Remaining block interleaver elements can be sequentially analyzed using the same method.
  • FIG. 5(b) illustrates how intra-row permutation is performed using a block interleaver. This method is more effective when the input direction of the block interleaver is a column direction.
  • the method of FIG. 5(b) can be considered the same as that of FIG. 5 (a) in terms of the purposes and characteristics of operations of the method. However, the method of FIG. 5(b) is performed in a different random reordering or permutation-related direction from that of FIG. 5 (a).
  • Interleaver elements can be cyclically shifted using cell-specific information such as a cell ID of each cell after the block random interleaving process is completed as described above. For example, an output sequence of the block interleaver for a cell having a shift factor of 0 can be directly mapped to physical REs without shifting and an output sequence of the block interleaver for a cell having a shift factor of 10 can be mapped to physical REs after cyclically shifting elements of the sequence by 10.
  • the cell-specific cyclic shift operation can be performed for the entirety of an output sequence of the block interleaver.
  • an interleaving element corresponding to the sum of a cell-specific value and a sequence position value (for example, a sequence index) indicating a position in the output sequence from the block interleaver can be mapped to an RE corresponding to the sequence index of the output sequence through the cell-specific shift operation.
  • a modulo operation using the size of the entire output sequence may be added such that the sum of the cell- specific value and the sequence index does not exceed the size of the entire output sequence.
  • the cell-specific cyclic shift operation can be performed on the block interleaver.
  • cyclic shifting can be performed on the block interleaver column by column in the same units in which permutation is performed.
  • Mathematical Expression 5 is an example representation of an intra-column random reordering operation to which a cyclic shift operation of interleaver elements using cell-specific information (for example, cell ID) is added.
  • Mathematical Expression 5 an operation for outputting a shift factor value through a cell ID is represented by a function S(Cell_ID).
  • Mathematical Expression 6 represents an example of the function S(CeIl ID).
  • Mathematical Expression 6 represents an example where a different shift factor is generated for each column together with cell-specific information. This example additionally uses a function CO(c) that adds a different offset to all elements of each column index c described above with reference to Mathematical Expression 2.
  • Mathematical Expressions 5 and 6 represent examples where cell-specific shift is performed after interleaving is done through a block interleaver by separately using a function that outputs a shift factor value, a cell-specific value can also be taken into consideration when interleaving is performed in the above Mathematical Expressions 2 to 4.
  • a function RR(r, c, Cell_ID) by additionally taking into consideration a unique factor such as a cell ID in a function for generating a unique reordering pattern of each column.
  • a function CH(r, c, Cell_ID) by additionally taking into consideration a unique factor such as a cell ID in a function for hopping to a unique value in each column or to define and use a function CO(c, CeIl ID) by additionally taking into consideration a unique factor such as a cell ID in a function for adding a different offset to all elements of each column index c.
  • Mathematical Expression 7 represents an example method of representing an algorithm that can implement virtual interleaving for an interleaving operation using the block interleaver described above.
  • R, C, and P may have the same values as those used when the block interleaver is implemented.
  • a function floor() is a truncation function which outputs the maximum of integer values equal to or less than an input value.
  • FIGs. 6(a) and 6(b) illustrate an example method for mapping a symbol sequence output from the block interleaver to physical resource elements according to the embodiment of the invention.
  • FIG. 6(a) represents an example where mapping is performed according to a time (OFDM symbol)-first mapping scheme. That is, in this method, the sequence of output symbols are sequentially mapped to physical resource elements, first on the time axis, by first increasing the OFDM symbol index in the mapping order.
  • FIG. 6(b) represents an example where mapping is performed according to a frequency (subcarrier)-first index mapping scheme. That is, in this method, the sequence of output symbols are sequentially mapped to physical resource elements, first on the frequency axis, by first increasing the subcarrier symbol index in the mapping order.
  • An index written in each block in FIGs. 6(a) and 6(b) is an index of a specific modulated symbol group transmitted through consecutive subcarriers. That is, #0 can represent physical resource elements to which modulated symbols included in a modulated symbol group 0 are mapped.
  • a single modulated symbol group includes four modulated symbols taking into consideration that the total number of transmit antennas is 4. From FIG. 6, it can be seen that modulated symbols are mapped to physical resource elements excluding those for transmitting reference signals RSO, RSl, RS2, and RS3 for the total of four antennas.
  • a control channel is transmitted using n OFDM symbols in a subframe corresponding to a Transmit Time Interval (TTI) in an OFDM communication system.
  • TTI Transmit Time Interval
  • n represents the number of OFDM symbols carrying a control channel.
  • LTE Long-Term Evolution
  • n can be selected from natural numbers equal to or less than 3 (n ⁇ 3).
  • modulated symbols in a modulated symbol sequence of control channel information can be mapped to REs, respectively.
  • the modulated symbol sequence may be a sequence of symbols generated after a sequence of control channel information bits undergoes all or part of channel coding and rate matching, cell-specific scrambling, and modulation as described above.
  • a Control Channel Element which is a virtual resource used for control channel scheduling, can be defined as an element for transmitting a control channel of a single terminal. Since the CCE is a logical resource, control information of a terminal can be actually transmitted through discontinuous physical resources even though the control information of the terminal is transmitted through a set of consecutive CCEs. Relations between logical/physical resources can be predefined in the system.
  • a group of modulated symbols in a CCE mapped to each REG can be defined as a mini-CCE when taking into consideration mapping to an REG including REs corresponding to the same number of consecutive subcarriers as the number of transmit antennas according to a multiple antenna transmission scheme. For example, modulated symbols in one mini-CCE can be mapped to one REG.
  • the sizes of a mini-CCI and an REG can be determined to correspond to each other.
  • Each of the sizes of a mini-CCI and an REG can be defined as including a variable number of modulated symbols.
  • a mini-CCE can be considered a resource unit that includes a number of modulated symbols corresponding to the number of transmit antennas.
  • a mini-CCE and an REG can each be defined as a modulated symbol group including a fixed number of consecutive modulated symbols.
  • a mini-CCE can be considered a resource unit including the same number of modulated symbols as the number of subcarriers included in a unit for application of an SFBC+FSTD technique, which combines Space Frequency Block Coding (SFBC) and Frequency Switched Transmit Diversity (FSTD) techniques, so that the coding technique enabling simultaneous application of the SFBC and FSTD techniques is applied in a fixed format or manner.
  • SFBC+FSTD technique which combines Space Frequency Block Coding (SFBC) and Frequency Switched Transmit Diversity (FSTD) techniques, so that the coding technique enabling simultaneous application of the SFBC and FSTD techniques is applied in a fixed format or manner.
  • the amount of control information that can be transmitted through a CCE can be defined according to a predefined coding rate and modulation method. Pieces of corresponding control information can be transmitted through one or more CCEs so as to provide a terminal with a coding rate achieving a specified reception quality with a modulation method having been defined.
  • control information bits transmitted through a CCE can be defined as 48 bits when it is assumed that a CCE in a system transmission band includes 36 REs, the coding rate is 2/3, and the data modulation scheme is Quadrature Phase Shift Keying (QPSK). Pieces of corresponding control information may be transmitted through CCE aggregation of one or more CCEs so as to provide a terminal with a coding rate achieving a specified reception quality with a modulation method having been defined.
  • QPSK Quadrature Phase Shift Keying
  • Different CCEs can be defined for control information for downlink data and control information for uplink data since the size of control information for downlink data and the size of control information for uplink data may be different.
  • a base station performs scheduling for control channel transmission to multiple terminals through one or more CCEs and then transmits a control channel by mapping the control channel to multiple REs or REGs in the physical domain.
  • CCE to RE mapping a process for mapping CCEs to resources in the physical domain.
  • One CCE-to-RE mapping method that can be considered is distributed mapping.
  • this method it is preferable that a control channel of a specific terminal or CCEs included in the control channel be mapped to physical REs in a distributed manner over n OFDM symbols and a total system band.
  • CCE-to-RE mapping method Another CCE-to-RE mapping method that can be considered is cell-specific mapping.
  • this method it is preferable that CCEs be mapped to physical REs in a cell-specific pattern (i.e., in a unique pattern for each cell). This enables implementation of randomization of inter-cell interference in multi-cell environments.
  • CCEs of each cell are mapped to the same time/frequency resource elements and therefore inter-cell interference of transmission of CCEs may be significantly increased in a specific case of the method of allocation of transmission power of CCEs.
  • CCE aggregation actually refers to an Adaptive Modulation and Coding (AMC) level.
  • Transmission power control can be applied to each individual CCE aggregation level in a situation where limited CCE aggregation is supported in order to effectively maintain overhead of blind decoding of terminals.
  • significant inter-cell interference may occur in a specific CCE-to-RE mapping pattern in the case where the difference of transmission power between REs of the physical domain to which individual CCEs are mapped is very high.
  • cell-specific CCE-to-RE mapping be performed to achieve not only characteristics capable of distributing CCEs of each cell uniformly over the total time/frequency domain but also characteristics capable of minimizing the influence of inter-cell interference through randomization of the inter- cell interference.
  • FIG. 7 illustrates a mapping relation between virtual and physical resources in an OFDM communication system.
  • FIG. 7 illustrates an example where a Resource Element Group (REG) in an OFDM symbol is a group of k subcarriers, i.e., k Resource Elements (REs), where 1 ⁇ k ⁇ maximum number of transmit antennas supported in system.
  • REG Resource Element Group
  • mini-CCEs and REGs can be mapped one to one.
  • mini-CCEs in one CCE be mapped to REGs in a distributed manner through an interleaving operation using a block interleaver 600 according to the invention.
  • a modulated symbol sequence of CCEs output from the block interleaver 600 can be sequentially mapped to physical REs in the frequency or time domain in the order from physical REs of a first OFDM symbol to those of an nth OFDM symbol.
  • a specific rule can also be applied when modulated symbols are sequentially mapped to the frequency or time domain. In this process, it will be more effective to use a block interleaver with different input and output directions as described above.
  • At least one of the modulated symbols of every CCE transmitted in a subframe in a specific bandwidth interval is mapped to physical REs.
  • at least one REG may be mapped within a specific bandwidth interval.
  • mini-CCE 0 of CCE 0 can be mapped to REG 0 and mini-CCE i+1 of CCE 1 can be mapped to REG 1.
  • FIGs. 8(a) and 8(b) illustrate example methods for determining a block interleaver size according to an embodiment of the invention.
  • a block interleaver size according to the embodiment can be defined by the number of rows R and the number of columns C and the R and C values can be determined based on not only an input CCE size but also a detailed operating method of the block interleaver.
  • FIG. 8(a) illustrates an example method for determining a block interleaver size in the case where the direction of input of modulated symbols to the block interleaver is a row direction.
  • the number of columns C of the block interleaver can be determined to be the CCE size (i.e., the number of REs or REGs to which one CCE is mapped).
  • the number of rows R of the block interleaver can be determined to be the maximum number of CCEs that can be transmitted in one subframe.
  • channel in n OFDM symbols can be changed by transmission of another channel, some
  • REG may remain even when a maximum number of CCEs have been mapped to C
  • the maximum number of CCEs plus 1 can be determined to be the number of rows R.
  • K through an OFDM symbol can be defined to be — .
  • R can be set to
  • NCCE + 1 if K is greater than NCCE * C and R can be set to NCC E if K is equal to N CCE * C.
  • the number of rows R of the block interleaver be set to a prime number. If the determined R value is a prime number, it can be directly determined to be the number of rows R of the block interleaver. If the determined R value is not a prime number, the smallest prime number greater than the determined R value can be determined to be the number of rows R of the block interleaver.
  • K is the total number of REs or REGs that can be used for transmission of a control channel in n OFDM symbols used for transmission of downlink control channels through a subframe.
  • mapping can be performed by pruning the same number of elements as the difference between R* C and K.
  • K REs may include N CCE *C REs used for CCE transmission and remaining K-(NCCE*C) RES used for other channel transmission.
  • the frequency domain diversity can be optimized by determining the block interleaver size also taking into consideration K-(N CC E*C) RES, which are not used for transmission of CCEs, among a total of K REs and performing block interleaving according to the determination.
  • the total number of K REs or REGs that can be used for control channel transmission may exclude the number of REs used for transmission of a Reference
  • RS Reference Signal
  • PCFICH Physical Control Format Indication Channel
  • Control Channel Format Indicator which is information regarding a control channel transport format, a Paging Indicator Channel (PICH) or a Physical Hybrid- ARQ
  • PHICH Indicator Channel
  • FIG. 8(b) illustrates an example method for determining a block interleaver size in the case where the direction of input of modulated symbols to the block interleaver is a column direction. Details of the implementation method of FIG. 8(b) are similar to those of FIG. 8 (a) described above with the only difference being that the number of columns C of the block interleaver can be determined to be the maximum number of CCEs that can be transmitted in one subframe and the number of rows R of the block interleaver can be determined to be the CCE size (i.e., the number of REs or REGs included in one CCE).
  • the number of rows and the number of columns of the block interleaver are basically defined based on the maximum number of CCEs that can be transmitted within available physical REs in association with CCEs which are basic scheduling units for transmission of control channel information.
  • CCEs which are basic scheduling units for transmission of control channel information.
  • time/frequency domain diversity characteristics can be kept uniform by applying the pruning technique.
  • the number of rows or columns of the block interleaver i.e., the size of the block interleaver
  • the number of rows or columns of the block interleaver can be increased or decreased according to the total number of available physical REs and the number of rows and columns can be changed or fixed with time depending on circumstances or conditions (or requirements).
  • mapping can be implemented after interleaving is performed using the block interleaver described above through a method of multiplexing CCEs for transmitting a control channel.
  • FIG. 9 illustrates an example multiplexing method which can implement interleaving using a block interleaver according to an embodiment of the invention.
  • FIG. 9 illustrates an example where a total of N CCEs (CCE 0, CCE 1, .., CCE N-I) can be transmitted through one subframe and each CCE includes a total of 9 mini-CCEs (mini-CCE 0 - mini-CCE 8).
  • a mini-CCE can be defined as an entity corresponding to a group of modulated symbols that are mapped to an REG according to a multiple antenna transmission technique among modulated symbols transmitted in a CCE as described above. For example, when the number of transmit antennas is 4, a modulated symbol group including a total of 4 modulated symbols can be defined as a mini-CCE. That is, in the following description, we can assume that each mini-CCE is mapped to an REG.
  • a group of mini-CCEs is constructed such that the group of mini-CCEs includes at least one mini-CCE of each of the N CCEs according to this embodiment.
  • the positions of mini-CCEs are mixed through random reordering or permutation based on a specific permutation pattern in a group of mini-CCEs.
  • the length of a random sequence generated through random reordering may be limited to the maximum number of CCEs that can be transmitted in a subframe.
  • CCE generated in a previous group and the position of a mini-CCE of the CCE generated in a current group be less than the number of REGs that can be transmitted in the first OFDM symbol.
  • FIG. 9 illustrates an example where a group is constructed such that it includes at least one of the mini-CCEs of each CCE. That is, a total of 9 groups including a group GO including a mini-CCE 0 of each CCE, a group Gl including a mini-CCE 1 of each CCE, ..., and a group G8 including a mini-CCE 8 of each CCE can be formed in the example of FIG. 9.
  • the positions of REGs in each group such as group GO, group Gl, ..., and group G9 can be randomly reordered.
  • the number of mini-CCEs in each group is equal to the number of rows (# of rows) and the number of groups is equal to the number of columns (# of columns).
  • This method can be commonly applied to every cell such that random reordering is performed for each group and a cell-specific shift of a mapping pattern is performed using cell-specific information such as a cell ID and mapping to physical REGs is then sequentially performed.
  • FIG. 10 illustrates a specification table provided to explain methods of operating a block interleaver according to an embodiment of the invention.
  • FIG. 10 Four types of operations shown in FIG. 10 are defined as block interleaving operations that are performed at a block interleaver to accomplish purposes of CCE-to- RE mapping.
  • the four types can be considered extensions of the two types described above with reference to FIG. 2.
  • an intra-column permutation or intra-row permutation operation and/or an inter-column permutation or inter-row permutation operation is performed
  • it is assumed in the description of FIG. 10 that an intra-column shift or intra-row shift operation and/or an inter-column shift or inter-row shift operation is performed.
  • input (writing) and output (reading) directions of a block interleaver can be set to be different in order to provide a basic diversity gain in the time-frequency domain.
  • a row- wise writing & column- wise reading type (Type 1) and a column- wise writing & row- wise reading type (Type 2) can be defined as two operating types.
  • Combinations of two types of shift and permutation methods can be defined for each of the two types of input/output methods (Type 1 and Type 2). In the following description, it is assumed that these combinations can provide a basic diversity gain in the frequency domain and can increase coverage and support balanced transmission power of control channels in the time domain.
  • Method 1 Two types of methods, i.e., intra-column shift & inter-column permutation (Method A) and intra-column shift & inter-row permutation (Method B) are associated with Type 1.
  • Method C intra-row shift & inter-row permutation
  • Method D intra-row shift & inter-row permutation
  • a different shift offset value or a different permutation pattern may be set for each row or each column so as to obtain effects maximizing diversity and randomization.
  • FIGs. 11 (a) and l l(b) illustrates a shift operation in an interleaving operation method using a block interleaver according to an embodiment of the invention.
  • N row denotes the number of rows and N co i denotes the number of columns.
  • the shift operation can be performed such that modulated symbol sequences of CCEs input to the block interleaver are shifted by a specific offset value in either a row or column direction of a block interleaver. For example, when an intra-column shift shown in FIG. 11 (a) is performed, the row positions of CCEs input to the same column of the block interleaver are changed by the same offset value. In addition, when an intra-row shift shown in FIG. ll(b) is performed, the column positions of CCEs included in the same row of the block interleaver are changed by the same offset value.
  • the intra-row shift operation is performed as shown in FIG. 11 (a) and, when the input direction of the block interleaver is a column direction and the output direction is a row direction, i.e., in the case of Type 2, the intra-column shift operation is performed as shown in FIG. ll(b), thereby improving diversity or randomization characteristics.
  • Time/frequency mapping characteristics can be maintained by shifting within a row or column alone taking into consideration input and output directions, and mapping patterns obtained after mapping is done can also be made various by defining a shift offset value (the extent of shift) for each row and for each column. More specifically, cell-specific information such as a cell ID can be used to generate a shift offset value or a shift pattern based on the shift offset value in the intra- row or intra-column shift operation as described above. If a shift pattern is generated using cell-specific information such as a cell ID, it is possible to generate a different interleaver output (i.e., a unique mapping pattern) for each cell even though an intra- column or intra-row shift operation is performed using the same interleaver structure for different cells as can be seen from FIGs. 1 l(a) and 1 l(b).
  • FIGs. 12(a) and 12(b) illustrate an example method for mapping a control channel interleaved using a block interleaver according to an embodiment of the invention.
  • interleaving is performed using a block interleaver according to Type 1 & Method A (row-wise writing & column-wise reading, intra- column shift, inter-column permutation).
  • FIG. 12(a) illustrates a procedure in which CCEs transmitted in a subframe are input to a block interleaver in a row direction of the block interleaver.
  • FIG. 12(b) illustrates a method for performing an intra-column shift operation among the block interleaving operations using a block interleaver.
  • Mathematical Expression 8 represents an example of the cell-specific intra- column shift.
  • R represents the number of rows of the block interleaver
  • C represents the number of columns
  • (r, c) represents an address of row and column before interleaving
  • (r ⁇ c') represents an address of row and column after interleaving
  • O Sh i f t represents a cell-specific factor used for a cell-specific intra- column shift operation.
  • FIG. 12(c) illustrates a method for performing an inter-column permutation operation among the block interleaving operations using a block interleaver.
  • Mathematical Expression 9 represents an example of the cell-specific inter- column permutation.
  • R represents the number of rows of the block interleaver
  • C represents the number of columns
  • (r, c) represents an address of row and column before interleaving
  • (r', c') represents an address of row and column after interleaving.
  • Op e rm represents a cell-specific factor used for a cell-specific inter- column permutation operation.
  • P represents a natural number relatively prime to C, which is the number of columns, and may have one or more values according to the value of C. If the cell-specific inter-column permutation operation is performed, the order of columns is changed using a unique Oshift value for each cell, so that the positions of columns is unique for each cell after the interleaving operation is performed.
  • FIG. 12(d) illustrates how interleaved modulated symbols of CCEs are output in a column direction from a block interleaver.
  • block interleaver operation is not changed and interleaving results may exhibit identical forms when input and output directions are changed.
  • an intra-column shift operation and an inter-column permutation operation which are operations of the block interleaver, are replaced with an intra-row shift operation and an inter-row permutation operation, respectively.
  • FIG. 12(e) illustrates partial results of mapping of an interleaved sequence of modulated symbols output from a block interleaver to time/frequency resources in a subframe.
  • mapping is performed in units of REGs, each including k REs, in order to support a transmit diversity technique of control channels, modulated symbols of CCEs are interleaved in units of modulated symbol groups, each including k modulated symbols, at the block interleaver and are then mapped to REGs in units of modulated symbol groups.
  • FIGs. 13 (a) to 13(d) illustrate another example method for mapping an interleaved control channel using a block interleaver according to the embodiment of the invention.
  • This embodiment provides a method for performing a permutation operation or a cell-specific inter-column permutation operation at an output procedure rather than separately performing the operations.
  • Embodiments of a CCE-to-RE mapping process at each step and block interleaver operations are described below in detail and specifically with reference to FIGs. 13(a) to 13(d).
  • interleaving is also performed using a block interleaver according to Type 1 & Method A (row-wise writing & column-wise reading, intra- column shift, inter-column permutation).
  • FIGs. 13(a) to 13(c) Operations of FIGs. 13(a) to 13(c) can be seen from the description of operations of FIGs. 12(a) to 12(c).
  • FIG. 13(c) also shows an output process.
  • modulated symbols are output in a column direction, wherein columns can be output in any order of columns rather than being output sequentially starting from the first column.
  • FIG. 13(d) illustrates partial results of mapping of an interleaved sequence of modulated symbols output from a block interleaver to time/frequency resources in a subframe. It can be seen from FIG. 13(d) that mapping results of FIG. 13(d) are identical to those of FIG. 12(e).
  • a Physical Resource Element (PRE) and a Physical Resource Element Group (PREG) can be constructed so as to include k adjacent REs among REs at positions other than positions of REs occupied by a reference signal, a
  • PCFICH PCFICH
  • PHICH PHICH among all REs present in n OFDM symbols and a given system bandwidth.
  • control channel elements are mapped to physical resource elements by performing block interleaving as described above, it is possible to minimize inter-cell interference in multi-cell environments while satisfying mapping requirements in the time/frequency domain described above.
  • Type 1 & Method B row-wise writing & column-wise reading, intra- column shift, inter-row permutation
  • Type 2 & Method C column-wise writing & rowwise reading, intra-row shift, inter-column permutation
  • Type 2 & Method D columnumn-wise writing & row-wise reading, intra-row shift, inter-row permutation
  • Mapping patterns generated through such processes and methods will have unique characteristics for each cell and satisfy time/frequency domain mapping and inter-cell interference randomization characteristics as in the case of Type 1 & Method A described in a section below.
  • a v(cell_ID,cell_ group _ID) function represents an intermediate function that can provide an RE mapping pattern index sequence adapted to each cell or each cell group using a cell ID or a cell group ID.
  • w(c) represents an output function for outputting a column-based shift offset for
  • Mathematical Expression 11 represents an embodiment of inter-row permutation for shifting a CCE group or all groups using a unique fixed offset for each cell.
  • offset(cell_ID) represents a function for generating a unique shift offset for each cell using a cell ID.
  • FIG. 14 illustrates an example where a block interleaver operates according to Mathematical Expression 11.
  • results of the inter-row permutation operation can be achieved by setting the same shift offset value for every column of the block interleaver as described above.
  • Mathematical Expression 12 can be considered an example implementation of inter-row permutation for coordination of inter-cell interference.
  • FIG. 15 illustrates an example where a block interleaver operates according to
  • a cell_ID value of "0" is set for cell A
  • a cell_ID value of "1” is set for cell B
  • a cellJD value of "2" is set for cell C.
  • This function can generate a cell-
  • Mathematical Expression 15 An embodiment in which a unique inter-row permutation operation for each cell is implemented together with an intra-column shift operation in the embodiment of Mathematical Expression 14 is represented by the following Mathematical Expression 15.
  • Mathematical Expression 16 represents an embodiment wherein a random value is generated for each column to apply a variable offset.
  • random _ gen' ⁇ cell _ ID, cell _ group _ ID) represents a function for generating a random value for each column in order to implement an embodiment wherein a shift offset is randomly allocated to an RE mapping pattern for an intra-column shift operation.
  • Mathematical Expression 17 represents an example method of representing an algorithm for implementing virtual interleaving for an interleaving operation using the block interleaver described above.
  • PREG(Z) represents 7-th physical resource element.
  • R represents the number of rows of virtual interleaving
  • C represents the number of columns
  • (r, c) represents an address of row
  • O pe r m represents a cell-specific factor used for a cell-specific inter-column permutation operation
  • O Sh i ft represents an offset value as a cell-specific factor used for a cell-specific intra-column shift operation.
  • P represents a natural number relatively prime to C, which is the number of columns, and may have one or more values according to the value of C.
  • Tables 2 to 5 illustrate some combinations of the values of P and ⁇ that can be used according to the value of C.
  • control channel elements are mapped to physical resource elements through the virtual interleaving procedure as described above, it is possible to satisfy the mapping requirements of time/frequency domain and to minimize inter-cell interference in multi-cell environments.
  • one or more groups each including one or more CCEs, can be defined for more efficient mapping and CCEs can be mapped using the defined groups.
  • FIGs. 16(a) and 16(b) illustrate a method for defining a specific group including all or part of one or more CCEs according to an embodiment of the invention.
  • FIG. 16(a) illustrates an example method in which CCEs constructed to be transmitted in a single subframe are integrated into a single modulated symbol sequence and groups of arbitrary numbers of CCEs or REs are defined in the integrated modulated symbol sequence.
  • FIG. 16(a) illustrates a method in which groups are defined in units of arbitrary numbers of CCEs and modulated symbols in each arbitrary number of CCEs are included in a corresponding group.
  • a total of n groups is defined and Group #1 includes CCE#1, CCE#2, ..., and CCE#L, Group #2 includes CCE#L+1, CCE#L+2, ..., and CCE#M, and Group #n includes CCE#M+1, CCE#M+2, ..., and CCE#N.
  • N is the total number of CCEs transmitted in a corresponding subframe.
  • FIG. 16(b) illustrates a method in which groups are defined such that each group includes one or more CCEs while modulated symbols included in a CCE can be distributed so as to be included in different groups.
  • FIG. 16(b) illustrates a group definition method in which each CCE is divided into one or more CCE segments and a segment(s) of every CCE is included in one group so that modulated symbols included in one CCE are distributed so as to be included in different groups.
  • a total of n groups are defined and each CCE is divided into a number of CCE segments (for example, n CCE segments) corresponding to the number of defined groups.
  • CCE segment #1 (Sl) of each CCE is included in Group #1
  • CCE segment #2 (S2) of each CCE is included in Group #2
  • CCE segment #n (Sn) of each CCE is included in Group #n.
  • the total number of defined groups, the number of CCEs included in one group, or the number of modulated symbols of each CCE included in one group can be determined in various manners. For example, these numbers can be determined in association with the following method for mapping to an OFDM symbol carrying a control channel using groups defined as described below.
  • FIGs. 17(a) and 17(b) illustrate the method for mapping to an OFDM symbol for transmitting a control channel using groups defined according to an embodiment of the invention.
  • FIG. 17(a) illustrates an example where groups are mapped respectively to n OFDM symbols for control channel transmission.
  • the total number of defined groups may be n and the number of modulated symbols included in one group may be determined to be proportional to or correspond to the number of Physical Resource Elements (PREs), which can be used for transmission of control information of CCEs, included in one OFDM symbol.
  • PREs Physical Resource Elements
  • FIG. 17(a) modulated symbols included in Group #1 are mapped to a first OFDM symbol in a subframe corresponding to a Transmit Time Interval (TTI), modulated symbols included in Group #2 are mapped to a second OFDM symbol, and modulated symbols included in Group #n are mapped to an nth OFDM symbol.
  • TTI Transmit Time Interval
  • FIG. 17(b) illustrates an example where one or more (for example, m) subbands, each including one or more subcarriers, are constructed in the frequency axis for a total of n OFDM symbols for control channel transmission.
  • each group is mapped to one of the m subbands.
  • the total number of defined groups may be m and the number of modulated symbols included in one group may be determined to correspond to the number of Physical Resource Elements (PREs), which can be used for transmission of control information of CCEs, included in one subband.
  • PREs Physical Resource Elements
  • modulated symbols included in Group #1 are mapped to a first subband in a subframe corresponding to a Transmit Time Interval (TTI)
  • modulated symbols included in Group #2 are mapped to a second subband
  • modulated symbols included in Group #m are mapped to an mth subband.
  • groups are sequentially mapped to the subbands in the example illustrated in FIG. 17(b)
  • the order of mapped subbands may be changed as needed as in the example of FIG. 17(a).
  • PREs that can be used for transmission of control information of CCEs may be
  • FIG. 18 illustrates another method for defining a group including all or part of one or more CCEs according to an embodiment of the invention.
  • the size of each CCE segment i.e., the number of modulated symbols included in each CCE segment
  • the size of each CCE segment can be determined independently of each other. That is, when each group has a different size, the size of each CCE segment can be determined to be proportional to the size of each group. For example, in the case where a total of 3 groups are defined and the ratio of the sizes of the groups is 1 :1:1.5, the ratio of the sizes of CCE segments included in each CCE may be determined to be the same as 1 :1 :1.5.
  • the ratio of the respective numbers of modulated symbols distributed to the n OFDM symbols may be equal to the ratio of the respective numbers (for example, Ml : M2: M3) of PREs that can be used for CCE transmission of the OFDM symbols.
  • Ml the respective numbers
  • M2: M3 the values of Ml, M2, and M3 are numbers obtained by subtracting the number of PREs used for other control information from M which is the number of PREs included in each of the OFDM symbols.
  • the number of PREs that can be used for CCE transmission may actually vary for each OFDM symbol due to other control information. Accordingly, if modulated symbols of one CCE are mapped to OFDM symbols by distributing the same number of modulated symbols over each OFDM symbol without taking into consideration the respective numbers of REs that can be used for CCE transmission in the OFDM symbols, the number of CCEs that can be transmitted in a subframe may be limited to the number of CCEs that can be transmitted through an OFDM symbol including the largest amount of other control information.
  • Each of the smallest rectangles 40 in the lower portion of FIG. 18 represents a
  • PRE and dark portions 41 represent PREs that are not used for actual CCE-to-RE mapping and, instead, are used for purposes other than CCE transmission.
  • An embodiment of a method in which modulated symbols of a CCE are divided and allocated to the OFDM symbols such that the respective modulated symbols allocated to the OFDM symbols are proportional to the respective numbers of PREs that can be used for CCE transmission in the OFDM symbols (for example, at a ratio of Ml : M2: M3) will now be described with reference to the following Mathematical Expressions. Notations used in the following Mathematical Expressions were selected for the sake of convenience and it will be apparent that it is possible to use any other notations with the same meanings.
  • N ⁇ ,bo . (,) CCEme -Yyrgt*®
  • NTM mm ⁇ NTM(i) ⁇
  • M denotes the number of PREs included in an OFDM symbol and M 1 denotes the number of PREs that can be used for control channel transmission in an ith OFDM symbol.
  • M 1 can be defined as the number of PREs other than all or part of PREs used for transmission of other control information.
  • CCE s iz e denotes the number of modulated symbols included in a CCE.
  • N ⁇ f ° ' is defined as the number of REs mapped to an ith
  • N ⁇ 1 ° ' can be determined to be proportional to a ratio between the number PREs that can be used for control channel transmission in n OFDM symbols and the number PREs that can be used for control channel transmission in the ith OFDM symbol as in the example of Mathematical Expression 18.
  • An operation such as flooring or rounding can be performed in order to obtain
  • adding 0.5 to N ⁇ 1 0 ' may be performed to obtain the same effects as rounding in
  • Ncclb i s defined as the maximum number of CCEs that can transmit
  • NTMTM E is defined as a value having the minimum value of NTMTM E (/) and the
  • NTM E X may be the maximum number of CCEs that can be transmitted in one subframe.
  • the distribution of modulated symbols of a CCE for each OFDM symbol can be adjusted so as to achieve uniform frequency diversity gain for each OFDM symbol even in environments where the number of PREs that can be used for CCE transmission in each OFDM symbol varies.
  • each PRE is defined as a pair of adjacent subcarriers in the case
  • the pair of adjacent subcarriers may include two closest subcarriers among all subcarriers excluding subcarriers to which pieces of information not transmitted through CCEs are mapped.
  • M ' the number of REs in an OFDM symbol
  • N symbo.(o the number of RES of a CCE in ,- . th symbol
  • Mathematical Expression 19 represents an example where calculation is made using PREs, each including two
  • each including two subcarriers, M, A/,-, and CCE s ⁇ ze can be redefined as M', M), and CCE ' S i Ze as illustrated in Mathematical Expression 2.
  • Mathematical Expressions 20 and 21 illustrate example calculations of Mathematical Expression 19 in the case where one CCE includes 36 REs and 48 REs and three OFDM symbols are used for a control channel when the system transmission
  • FIG. 19 illustrates a method for performing mapping using a group definition method according to an embodiment of the invention.
  • the first step (step 1) of the method can be referred to as a CCE grouping step.
  • N CCE CCES each of which includes modulated symbols constructed from a control information bit sequence to be transmitted in each subframe, or partial CCE segments of each CCE can be defined as one or more groups (for example, NQ R groups) for a given purpose.
  • the second step (step 2) can be referred to as a permutation step.
  • permutation can be performed on sequences of REs of all or each of the NQR groups generated through the CCE grouping process of the first step.
  • the final, third step can be referred to as an RE mapping step.
  • a modulated symbol sequence permutated at the above second step can be mapped to one or more PREs defined according to a specific RE mapping method according to a given purpose.
  • the method of mapping modulated symbols in CCEs to PREs in the time-frequency domain in a physical channel is defined as an RE mapping method.
  • An embodiment of the RE mapping method can be provided as follows.
  • a specific RE mapping method for mapping to specific REs to achieve the above purpose for a group(s) or all REs received from the previous step can be defined and performed at the third step.
  • the above steps can be combined to design a CCE-to-RE mapping procedure.
  • the steps of the CCE-to-RE mapping procedure may be designed independently of each other and may also be designed in association with each other or designed as an integrated procedure for the sake of simplifying and optimizing the procedure. Reference will now be made in more detail to various embodiments that can implement the steps described above.
  • FIG. 20 illustrates an example method for performing mapping using a group definition method according to an embodiment of the invention.
  • This embodiment is a detailed embodiment of step 1 of FIG. 19. Descriptions of operations of steps 2 and 3 are omitted since they are identical to those described above with reference to FIG. 19.
  • This embodiment relates to an example where a method for defining groups of modulated symbols of CCEs constructed to be transmitted in a subframe in units of an arbitrary number of CCEs or modulated symbols is applied at step 1 of FIG. 19.
  • CCEs constructed to be transmitted in a subframe are integrated into a modulated symbol sequence at step 1-1 of FIG. 20 and the integrated modulated symbol sequence is divided into one or more groups at step 1-2.
  • a method of defining groups in units of an arbitrary number of CCEs is referred to as CCE level grouping.
  • mapping to PREs defined in a time-frequency domain can be performed at the CCE level.
  • the number of groups NQ R generated by the grouping and the size of each group can be equal or different depending on a given purpose and situation. Reference will now be made to examples of a method for determining the number of groups NQ R generated by grouping and a CCE size of each group when the CCE level grouping scheme is applied.
  • FIG. 21 illustrates an example method using the CCE level grouping scheme according to an embodiment of the invention.
  • the example of FIG. 21 is an embodiment of the CCE level grouping scheme, i.e., an embodiment of steps 1-1 and 1-2 of FIG. 20, wherein grouping is performed for each OFDM symbol in the time domain. That is, in this case, CCEs are integrated at step 1-1 and the integrated modulated symbol sequence is divided into one or more groups at step 1-2.
  • the number of groups (N G R) generated by the grouping can be determined to be the number of OFDM symbols (n) and the CCE size of each group can be determined to be the number of available PREs included in an OFDM symbol corresponding to each group.
  • the size of each group can be equal or different depending on a given purpose and situation.
  • FIG. 22 illustrates another example method using the CCE level grouping scheme according to an embodiment of the invention.
  • FIG. 22 is an embodiment of the CCE level grouping scheme, i.e., an embodiment of steps 1-1 and 1-2 of FIG. 20, wherein grouping is performed for each subband including an arbitrary number of subcarriers in the frequency domain. That is, in this case, the number of groups (NQ R ) generated by grouping of an integrated RE sequence at step 1-1 can be determined to be the number of subbands (m) and the CCE size of each group can be determined to be the number of available PREs included in a subband corresponding to each group.
  • Each subband can be defined as a set of actual consecutive subcarriers or a set of subcarriers distributed in units of one or more subcarriers in a total system transmission band depending on the type of transmission. In this case, it is apparent that the size of each group can also be equal or different depending on a given purpose and situation.
  • FIG. 23 illustrates an example method for performing mapping using a group definition method according to an embodiment of the invention.
  • This embodiment is another detailed embodiment of step 1 of FIG. 19. Descriptions of operations of steps 2 and 3 are omitted since they are identical to those described above with reference to FIG. 19.
  • This embodiment relates to an example where the method for defining groups of modulated symbols of CCEs, such that modulated symbols included in a CCE are distributed so as to be included in different groups described above with reference to FIG. 2(b), is applied at step 1 of FIG. 19.
  • an operation for dividing modulated symbols included in each CCE into a number of CCE segments equal to or greater than the total number of groups is performed in order to distribute and map modulated symbols of CCEs.
  • one or more of the divided CCE segments of each CCE are combined into a group.
  • the method, in which each CCE is divided into one or more CCE segments and CCE segments are combined into a group in this manner, is defined as a CCE sub- block level grouping scheme.
  • the number of groups NQR generated by the grouping and the size of each group can be equal or different depending on a given purpose and situation. Reference will now be made to examples of a method for determining the number of groups NQ R generated by grouping and a CCE segment size of each group when the CCE sub-block level grouping scheme is applied.
  • FIG. 24 illustrates an example method using the CCE sub-block level grouping scheme according to an embodiment of the invention.
  • FIG. 24 is an embodiment of the CCE sub-block level grouping scheme, i.e., an embodiment of steps 1-1 and 1-2 of FIG. 23, wherein grouping is performed for each OFDM symbol in the time domain. That is, in this case, CCEs are divided into segments at step 1-1 and divided CCE segments are combined to generate one or more groups at step 1-2.
  • the number of groups (NQ R ) generated by the grouping can be determined to be the number of OFDM symbols (n) and the CCE segment size of each group can be determined to be the number of available PREs included in an OFDM symbol corresponding to each group.
  • the size of each group can be equal or different depending on a given purpose and situation.
  • FIG. 25 illustrates another example method using the CCE sub-block level grouping scheme according to an embodiment of the invention.
  • the example of FIG. 25 is an embodiment of the CCE sub-block level grouping scheme, i.e., an embodiment of steps 1-1 and 1-2 of FIG. 23, wherein grouping is performed for each subband including an arbitrary number of subcarriers in the frequency domain. That is, in this case, the number of groups (N GR ) generated by grouping divided CCE segments at step 1-1 can be determined to be the number of subbands (m) and the CCE size of each group can be determined to be the number of available PREs included in a subband corresponding to each group.
  • N GR the number of groups generated by grouping divided CCE segments at step 1-1
  • m the number of subbands
  • the CCE size of each group can be determined to be the number of available PREs included in a subband corresponding to each group.
  • Each subband can be defined as a set of actual consecutive subcarriers or a set of subcarriers distributed in units of one or more subcarriers in a total system transmission band depending on the type of transmission. In this case, it is apparent that the size of each group can also be equal or different depending on a given purpose and situation.
  • the CCE level grouping scheme can be applied in conjunction with the CCE sub-block grouping scheme.
  • groups may be defined for some CCEs by dividing each CCE into CCE segments according to the CCE sub-block level grouping scheme and groups may be defined for some CCEs without dividing each CCE into CCE segments according to the CCE level grouping scheme.
  • the positions of modulated symbols of one or more groups generated through the process of step 1 are changed in the permutation process of step 2 in the method of FIG. 20.
  • a single permutation pattern can be applied or an independent permutation pattern can be applied for each individual RE group when the permutation is performed individually for each of the groups generated at step 1.
  • all groups may be integrated and the permutation method of step 2 may be performed as a single process on the integrated groups.
  • the same RE mapping method as described above is applied to all cells, the same RE mapping method is provided for each cell. In this situation, the influence of inter-cell interference may be significant if the same RE mapping method is applied to each cell when power control of the control channel is applied and frequency-domain load of the control channel is great compared to a system transmission band in a given cell.
  • cell-specific permutation method include a method for adjusting interference between cells by coordinating the
  • RE mapping method of each cell a method for randomizing inter-cell interference by statistically multiplexing resources, which are commonly used by each cell in a specific
  • FIG. 26 illustrates a method for performing mapping using a group definition method according to an embodiment of the invention.
  • This embodiment is a detailed embodiment of step 2 of FIG. 19. Descriptions of operations of steps 1 and 3 are omitted since they are identical to those described above with reference to FIG. 19.
  • This embodiment provides an RE mapping index permutation method as a method for performing the permutation process.
  • the RE mapping index permutation method is a permutation method in which a sequence of modulated symbols of each arbitrary group or all groups defined at step 1 is reordered through cyclic shift using a predetermined shift offset.
  • a sequence of modulated symbols of each arbitrary group or all groups is reordered through cyclic shift using a cell-specific shift offset in order to achieve coordination or randomization of inter-cell interference in multi-cell environments.
  • a cell-specific RE mapping index offset of each cell can be generated using a unique index of each cell such as a cell ID or a cell group ID.
  • the implementation of RE mapping index permutation through shift with a specific uniform-interval offset extracted by a cell ID or a combination of a cell ID and a cell group ID may be considered implementation for coordination of typical inter- cell interference.
  • the method of performing permutation using a different random value for each subframe in the time domain and a random permutation pattern generated by a cell ID or a combination of a cell ID and a cell group ID can be considered a method implemented for randomization of statistical inter-cell interference.
  • FIG. 27 illustrates an example method for performing mapping using a group definition method according to an embodiment of the invention.
  • This embodiment is a detailed embodiment of step 2 of FIG. 19. Descriptions of operations of steps 1 and 3 are omitted since they are identical to those described above with reference to FIG. 19.
  • This embodiment provides inter-CCE permutation as a method for performing the permutation process.
  • the inter-CCE permutation method is a permutation method in which a sequence of modulated symbols of each arbitrary CCE or CCE segment group or a sequence of modulated symbols of all CCEs is reordered using a specific pattern. That is, using this permutation method, it is possible to perform mapping to PREs according to a specific RE mapping method while multiplexing multiple CCEs, thereby spreading interference.
  • the order of modulated symbols in a modulated symbol sequence of each arbitrary CCE or CCE segment group or a sequence of modulated symbols of all CCEs can be changed using a cell-specific permutation pattern in order to spread the influence of inter-cell interference over multiple CCEs in multi-cell environments as described above.
  • a cell-specific permutation pattern of each cell can be generated using a unique index of each cell such as a cell ID or a cell group ID.
  • this RE mapping index permutation method can be basically considered an intra-column shift operation in the block interleaver.
  • FIG. 29 illustrates an example configuration of a block interleaver that implements the CCE-to-RE mapping method according to an embodiment of the invention.
  • each of the n block interleavers may be equal to N ⁇ s bol(l) x NTMc E (/) .
  • N ⁇ * o ⁇ o of each of the NTM E ⁇ i) CCEs to be mapped to an ith OFDM symbol is input to the block interleaver in a row direction of the block interleaver.
  • REs can be sequentially output in a column direction so that the output REs are mapped to PREs of a corresponding physical resource domain according to the RE mapping method and are then transmitted through the mapped PREs.
  • CCE(O) is input to the first row of the block interleaver of the ith OFDM symbol. Then, CCE(O) is input to the second row, CCE(I) is input to the third row, and CCE( NTM * (/)-l)is input to the JVTM * (/)th row.
  • FIG. 30 illustrates an example configuration of a block interleaver that implements the CCE-to-RE mapping method according to an embodiment of the invention.
  • a group can be constructed from CCEs for each OFDM symbol.
  • the number of PREs remaining for each OFDM symbol may exceed the number of REs of the CCE.
  • the excess PREs can be allocated for transmission of an additional CCE.
  • Mathematical Expression 22 represents a method applied when the number of PREs remaining for each OFDM symbol exceeds the number of REs in a CCE.
  • NTMTM E is defined as a minimum value of N ⁇ E (i) for each
  • PREs which are not used for transmitting modulated symbols of CCEs for each OFDM symbol.
  • the number of PREs which are not used for CCE transmission for each OFDM symbol can be defined as Q(i) and Mathematical Expressions 18 and 19 can be referred to for other notations.
  • l and *W are defined when the sum of ⁇ v) of the n OFDM symbols is greater than CCE s ⁇ ze .
  • l is the number of CCEs that can be transmitted in addition to NS CCEs in the subframe.
  • k(i) is the number of rows in an interleaver of an ith OFDM symbol, which are used for transmitting ⁇ more CCEs other than N ⁇ E CCEs, other than N ⁇ l rows m the interleaver of the ith OFDM symbol.
  • the number of used PREs may be insufficient for M 1 .
  • Q (i) is defined to use all PREs remaining in this case.
  • Q (i) represents a smaller number of PREs than
  • FIG. 30(a) illustrates an example configuration of an interleaver of an ith
  • FIG. 30(b) illustrates an example configuration of respective interleavers of n OFDM symbols
  • tJ v/ 9 / , and '*' can reduce the number of PREs that are not used for CCE transmission in each OFDM symbol.
  • mapping to PREs may not performed for columns in a k(i)th row whose column indices are greater than the length of Q (i) when Q (i) is greater than 0.
  • the same number of k rows as the maximum of k(i) of n OFDM symbols used for CCE transmission can be added to NTM E rows to transmit / more CCEs.
  • the input and output of the interleaver can be estimated based on indices of the interleaver. Therefore, when k rows are added for one OFDM symbol so that the number of modulated symbols in the CCE exceeds M 1 , mapping to PREs may not be performed by carrying out puncturing based on the indices.
  • Mathematical Expression 23 represents an example of generalization of a function v(cell __ ID, cell _ group _ /D) that represents coordination and randomization for allocating a cell-specific RE mapping scheme and a general function w(c) for various types of implementation of inter-CCE permutation.
  • v(cell _ ID, cell _ group _ ID) is a generalized representation of a function that intermediates an intra-column shift operation that can generate a unique RE mapping scheme for each cell or each cell group based on cell_ID and cell_group_ID.
  • w(c) is a generalized representation of a function for generating various offsets that can be used for inter-CCE permutation.
  • FIG. 31 illustrates an example method for performing control channel mapping using a block interleaver according to an embodiment of the invention.
  • Frequency diversity can be obtained in units of resource blocks, each including an arbitrary number of PREs, in the time-frequency domain in distributed time- frequency resource conditions of an OFDM communication system.
  • resource blocks can be considered units of OFDM symbols and can also be considered subband units, each including a predetermined number of subcarriers as described above.
  • NTM is the number of CCEs per resource block and N m is the total number of resource blocks used for control channels in the system.
  • N% is the number of resource blocks used for a group of N° C r E CCEs.
  • N m (and N R G B r as needed) can be applied as values in an OFDM symbol.
  • N ant subcarriers are defined as one RE when N ant transmit antennas are used for SFBC employing a multiple antenna transmit diversity scheme.
  • mapping is performed in an RE-level distributed transmission mode in a resource block level when N ant transmit antennas are used, the value of NTM is equal to N anh
  • N% is defined as the product of N° C r E and N ⁇ E which is the number of REs per
  • CCE, and iV ra is defined as the product of N ⁇ and N Gr , thereby implementing mapping of the transmission mode.
  • FIGs. 32 and 33 illustrate, in a stepwise manner, example operations of a block interleaver constructed according to an embodiment of the invention.
  • FIG. 32 illustrates an input process and an intra-column shift operation of the block interleaver
  • FIG. 33 illustrates an inter-column permutation operation, an inter-row permutation operation, and an output process of the block interleaver.
  • step 1 CCEs used for a total control channel are sequentially input to the block interleaver in a row direction and, at step 2, an intra-column shift operation is performed in units of N% rows in order to distribute modulated symbols in each CCE over N% resource blocks in a corresponding group for each CCE.
  • a shift offset of each column can be determined as expressed in the following Mathematical Expression 24. [MATHEMATICAL EXPRESSION 24]
  • k is an integer value that defines a column- based shift offset.
  • inter-column permutation is performed in order to distribute CCEs in a resource block.
  • a permutation pattern used in this process may use a previously suggested scheme or a scheme defined to be optimized for the number of columns "JV""'.
  • randomization of inter-cell interference can be implemented as an operation for shifting by a fixed value uniquely generated for each cell through a cell ID or a combination of a cell ID and a cell group ID.
  • randomization of inter-cell interference can be implemented as an operation of shifting uniquely in each row by applying values generated by a random generation function obtained from a cell ID and a cell group ID to each subframe unit in the time domain or each row unit corresponding to a resource block in the frequency domain or both the units in the time-frequency domain.
  • step 4 it is possible to implement a function to locate resource blocks so as to achieve frequency diversity in a total system transmission band and a function to apply coordination of inter-cell interference by assigning a cell-specific offset to each cell.
  • M is a value representing the distance between
  • modulated symbols are sequentially read and output from the block interleaver in a row direction and modulated symbols corresponding respectively to elements of each row are mapped to REs of each resource block.
  • FIG. 34 is a flow diagram sequentially illustrating CCE-to-RE mapping processes according to an embodiment of the invention.
  • FIG. 34 illustrates CCEs and changes in the positions of modulated symbols in the CCEs when an interleaving operation has been performed at each step in the case where a block interleaving operation is implemented in a cell A according to the 5 steps described above with reference to FIGs. 31 to 33.
  • FIG. 34 illustrates CCEs and changes in the positions of modulated symbols in the CCEs when an interleaving operation has been performed using a different shift offset and permutation pattern different from those of the cell A in the case where a block interleaving operation is implemented in another cell (i.e., cell B) according to the 5 steps described above with reference to FIGs. 31 to 33.
  • EMBODIMENT 7 when an arbitrary one of a variety of downlink control channels is transmitted through one or more OFDM symbols, interleaving can be performed on modulated symbols or mini-CCEs included in a CCE of the arbitrary control channel transmitted through each OFDM symbol.
  • modulated symbols or mini-CCEs of CCEs are divided into n groups so that the modulated symbols or mini-CCEs can be transmitted through n OFDM symbols and interleaving is performed on modulated symbols or mini-CCEs of CCEs transmitted through the same OFDM symbol, taking into consideration the respective OFDM symbols to which the groups are mapped.
  • FIG. 35 illustrates an example method for performing mapping after interleaving is done for each OFDM symbol according to an embodiment of the invention.
  • FIG. 35 illustrates an example procedure in which CCEs, which are unit elements of a control channel, are combined to perform interleaving and are then mapped to one or more OFDM symbols.
  • interleaving is performed on mini-CCEs in CCEs transmitted through the same OFDM symbols.
  • a control channel includes one or more CCEs, and each CCE is divided into one or more sub-blocks at step S200.
  • this process serves to distribute and transmit each CCE over the OFDM symbols carrying the control channel, thereby increasing diversity gain and making power of each symbol as uniform as possible.
  • each of the CCEs CCE 1 (21), CCE 2 (22), and
  • CCE 3 (23) is divided into three sub-blocks in the case where the number of OFDM symbols carrying a control channel is 3.
  • the size of each CCE sub-block size i.e., the number of mini-CCEs included in each sub-block, is determined according to a ratio of the number of physical resource element groups that can be used for transmission of a specific control channel(s) or all control channels among remaining resource elements, other than resource elements used for a specific signal or channel such as a reference signal, to the total number of resource elements that can be used for each OFDM symbol.
  • mini-CCEs included in the first sub-block of each CCE are transmitted through the first OFDM symbol 27
  • mini-CCEs included in the second sub- block of each CCE are transmitted through the second OFDM symbol 28
  • mini- CCEs included in the third sub-block of each CCE are transmitted through the third OFDM symbol 29.
  • OFDM symbol can be represented by the following Mathematical Expression 29. [MATHEMATICAL EXPRESSION 29]
  • k is a variable indicating the number of resource elements used in one mini-CCE. This variable is used when a multiple antenna transmit diversity scheme is applied as described above.
  • the number N ⁇ G of available resource element groups can be determined excluding the number of resource element groups used for transmission of all or part of channels such as a PCFICH, a PHICH, and a
  • Mathematical Expression 30 represents an example method for determining the number of mini-CCEs M t included in each sub-block when each CCE is divided into sub-blocks.
  • Mathematical Expression 30 represents a method for determining the number of mini-CCEs M ; included in each sub-block by multiplying the total number of mini-
  • the number of mini-CCEs M, included in each sub-block is determined using the method of Mathematical Expression 30, it is possible to more efficiently perform the method for performing interleaving for each mini-CCE transmitted through the OFDM symbols according to this embodiment since the size of each sub-block is determined using the ratio of the number of available resource element groups for each OFDM symbol.
  • an interleaving set is constructed from each CCE by combining sub-blocks of each OFDM symbol.
  • the interleaving set is a unit for interleaving.
  • An interleaving set 24 associated with the first OFDM symbol, an interleaving set 25 associated with the second OFDM symbol, and an interleaving set 26 associated with the third OFDM symbol are illustrated in FIG. 35.
  • interleaving is performed on each interleaving set. That is, interleaving is performed for each OFDM symbol.
  • interleaving may be performed using a cell-specific pattern or a cell-common pattern in multi-cell environments.
  • a random pattern can be used to reduce inter-cell interference or a specific permutation pattern or an arbitrary permutation pattern can be used to reduce inter-cell interference. It is also possible to use a method of performing shifting using a cell-specific value based on cell-specific information such as a cell ID.
  • a block interleaver can be used to perform interleaving at step S220. Interleaving can be performed for each row or column of the block interleaver. A random pattern or a specific permutation pattern can be used as the interleaving pattern as described above. Details of the configuration and operation of the block interleaver will be described below with reference to FIG. 35.
  • mini-CCEs interleaved for each of the first, second, and third OFDM symbols 27, 28, and 29 are mapped to resource element groups in the corresponding OFDM symbol and are then transmitted through the mapped resource element groups at step S230.
  • the number of mini-CCEs allocated to each individual OFDM symbol of each control channel can be set to be different according to an index of each CCE or control channel so as to support as many control channels or as many as CCEs required to transmit control channels in a subframe as possible.
  • the number of mini-CCEs can be set to be different according to whether the index of the control channel or CCE is even or odd.
  • the number of mini-CCEs for indices set in a specific period among total indices can be set to be different from the number of mini-CCEs for remaining indices.
  • some indices can be specified and the number of mini-CCEs in an OFDM symbol for the specified indices can be set to be different from that of remaining indices.
  • Mathematical Expression 31 represents an example method for determining the number iVTM n ' ⁇ CCE of mini-CCEs, which are transmitted through each ith OFDM symbol, in a jth CCE among all CCEs of control channels in a subframe.
  • N ⁇ in ,-cc E M ⁇ + [(y + L//2j)%2] - [ ⁇ (/ + l) - 2 3 -" ⁇ %2]
  • Mathematical Expression 30 can be used as the number of mini-CCEs M 1 included in each sub-block in Mathematical Expression 31.
  • an index j identifying each CCE ranges from 0 to the minimum of the respective numbers of CCEs that can be transmitted through the OFDM symbols.
  • the ratio of the respective numbers of mini-CCEs of OFDM symbols will be determined to be 1 :3:5 for each CCE.
  • a fixed ratio is not applied as the value of M t and, instead, the respective numbers of mini-CCEs transmitted for the OFDM symbols can be controlled flexibly within a predetermined range of the ratio, thereby supporting a larger number of control channels or a larger number of CCEs required to transmit control channels than when a fixed ratio is applied.
  • Mathematical Expression 33 represents another example method for determining the number NTM n ' ⁇ CCB of mini-CCEs, which are transmitted through each ith OFDM symbol, in a jth CCE among all CCEs of control channels in a subframe.
  • NTM n/ - CC£ M ; . + i ,
  • the number of available resource element groups of a control channel of interest can be calculated excluding resource element groups carrying a different type of control channel from the control channel of interest as described above. In this case, if the number of OFDM symbols carrying a different type of control channel or the number of resource element groups for each OFDM symbol is changed, then the number of available resource element groups for the control channel of interest can also be changed. Accordingly, the method can also be applied to this case.
  • the example of Table 6 can be considered an example that can be applied when a different type of control channel is transmitted through a first OFDM symbol and the example of Table 7 can be considered an example that can be applied when a different type of control channel is transmitted through all the three OFDM symbols allocated for control channel transmission.
  • the example of Table 8 can be considered an example that can be applied when a different type of control channel is transmitted through first and second OFDM symbols.
  • FIG. 36 illustrates an example method for transmitting different types of control channels according to an embodiment of the invention.
  • This embodiment provides a method in which, when different types of control channels are transmitted, interleaving is performed on mini-CCEs included in CCEs of one or more types of control channels instead of individually performing interleaving for each of the types of control channels.
  • downlink control channels include not only a PDCCH transmitting control information of downlink transmission data but also various types of control channels such as a PCFICH, a PHICH, and a PICH and a reference signal.
  • FIG. 36 illustrates an example in which a PCFICH 30, a PHICH 31, and a PDCCH 32 are transmitted as downlink control channels.
  • the PCFICH 30 should generally be separately taken into consideration since the position of the PCFICH 30 transmitted in the OFDM symbol is predetermined, it is possible to take into consideration the PHICH 31 and the PDCCH 32 together so that both the PHICH 31 and the PDCCH 32 can be mapped to resource element groups of OFDM symbols and then be transmitted through the mapped resource element groups.
  • interleaving can be performed taking into consideration the PHICH 31 and the PDCCH 32 together so that both the PHICH 31 and the PDCCH 32 can be mapped to resource element groups of OFDM symbols and then be transmitted through the mapped resource element groups. It will also be possible to apply the method in which interleaving is performed on each mini-CCE transmitted for each OFDM symbol as described above with reference to FIG. 35.
  • an interleaving set for performing interleaving taking into consideration all CCEs of the PHICH 31 and the PDCCH 32 can be determined at step 300 and interleaving can be performed to transmit them through one or more OFDM symbols at step S310.
  • To determine the interleaving set at step S300 it is possible to apply a method identical or similar to the method described above with reference to FIG. 35.
  • the PHICH can be defined separately from the PDCCH. For example, even when a total of three OFDM symbols is used for PDCCH transmission, the PHICH can use only one OFDM symbol. That is, the PHICH can be transmitted selectively using at least one of the
  • the OFDM symbol transmitting the PHICH can be defined as a PHICH duration, which can be divided into a normal mode and an extended mode.
  • a PHICH duration which can be divided into a normal mode and an extended mode.
  • the use of the OFDM symbols for transmitting the PHICH can be defined such that the PHICH is transmitted using the first of the OFDM symbols carrying control channels in the case of the normal mode and the PHICH is transmitted using all the OFDM symbols carrying control channels in the case of the extended mode.
  • FIG. 37(a) illustrates an example method for allocating mini-CCEs of PHICHs transmitted through each OFDM symbol when the PHICH duration is "1." In the case where the PHICH duration is "1," the PHICH is transmitted only through the first
  • K PHICHs are all interleaved together during the interleaving of the first OFDM symbol without performing separate allocation.
  • FIG. 37(b) illustrates an example method for allocating mini-CCEs of PHICHs transmitted through each OFDM symbol when the PHICH duration is "2."
  • the PHICH duration is "2”
  • the PHICH is transmitted through the first and second OFDM symbols and therefore it is difficult to transmit one PHICH using two OFDM symbols uniformly in the case where one PHICH consists of three mini-CCEs as in this embodiment.
  • a different rate of use of each OFDM symbol can be applied to each PHICH so that it is possible to transmit each PHICH using two OFDM symbols uniformly when a total of K PHICHs are taken into consideration.
  • two mini-CCEs of PHICH #0 can be transmitted through the first OFDM symbol and the remaining one mini-CCE can be transmitted through the second OFDM symbol.
  • one mini-CCE can be transmitted through the first OFDM symbol and the remaining two mini-CCEs can be transmitted through the second OFDM symbol, unlike the case of PHICH #0. Repeating this pattern will allow each PHICH to be transmitted using two OFDM symbols uniformly when a total of K PHICHs are taken into consideration.
  • FIG. 37(c) illustrates an example method for allocating mini-CCEs of PHICHs transmitted through each OFDM symbol when the PHICH duration is "3."
  • each PHICH consists of mini-CCEs
  • mini-CCEs of each PCFICH can be transmitted through each OFDM symbol.
  • the following Mathematical Expression 34 represents an example method for determining the number iV,TM n 'J ⁇ H of mini-CCEs transmitted through an ith OFDM symbol in a kth PHICH.
  • Mathematical Expression 34 represents an example method for determining the number iV,TM n 'J ⁇ H of mini-CCEs transmitted through an ith OFDM symbol in a kth PHICH. [MATHEMATICAL EXPRESSION 34] x rmin ⁇ -CC£ mmi-CCE
  • N PHICH represents a PHICH duration
  • FIG. 38 differs from that of FIG. 35 in that two different types of control channels, a PDCCH and a PHICH for ACK/ ⁇ ACK transmission, are taken into consideration together.
  • FIG. 38 illustrates an example where the PHICH is transmitted through only the first OFDM symbol while the PDCCH is transmitted through three OFDM symbols.
  • mini-CCEs in CCEs of the PHICH and the PDCCH that has been determined to be transmitted through the first OFDM symbol are input together to an interleaver 50 of the first OFDM symbol so that the mini-CCEs in the PHICH and the PDCCH are interleaved together at the interleaver 50.
  • FIG. 39 illustrates another example method for transmitting two or more different types of control channels by performing interleaving on the different types of control channels together for each OFDM symbol according to an embodiment of the invention.
  • the method of FIG. 39 is similar to that of the embodiment of FIG. 35, the method of FIG. 38 differs from that of FIG. 35 in that two different types of control channels, a PDCCH and a PHICH, are taken into consideration together. Specifically,
  • FIG. 39 illustrates an example where the PHICH is transmitted through three OFDM symbols while the PDCCH is also transmitted through the three OFDM symbols.
  • mini-CCEs in CCEs of the PDCCH and mini-CCEs in the PHICH that has been determined to be transmitted through the first OFDM symbol are input together to an interleaver 60 of the first OFDM symbol so that the mini-CCEs in the PHICH and the PDCCH are interleaved together at the interleaver 60.
  • mini-CCEs in CCEs of the PDCCH and mini-CCEs in the PHICH determined to be transmitted through the second OFDM symbol are input together to an interleaver 61 of the second OFDM symbol so that the mini-CCEs in the PHICH and the PDCCH are interleaved together at the interleaver 61.
  • mini-CCEs in CCEs of the PDCCH and mini-CCEs in the PHICH determined to be transmitted through the third OFDM symbol are input together to an interleaver 62 of the third OFDM symbol so that the mini-CCEs in the PHICH and the PDCCH are interleaved together at the interleaver 62.
  • resource element groups transmitting different types of control channels that are interleaved together are taken into consideration as opposed to being excluded when the number of available resource element groups is determined in each OFDM symbol.
  • the resource element groups may be multiplexed in a sequential manner and may also be distributed and multiplexed for the sake of optimizing frequency domain diversity.
  • a block interleaver is used to perform interleaving on each OFDM symbol according to the invention.
  • a block interleaver that operates with different input and output directions.
  • the order of elements before they are input to the block interleaver and the order of elements that are output from the block interleaver can be changed (or can be made different) through the simple method of using different input and output directions, thereby allowing channel elements to be distributed and transmitted uniformly over resources.
  • a block interleaver which performs row-wise writing (or row-directional input) and column-wise reading (or column-directional output), permutes row positions of elements in each column and outputs the elements.
  • a block interleaver which performs column- wise writing (or column-directional input) and column-wise reading (or row-directional output), permutes column positions of elements in each row and outputs the elements.
  • permutation can be performed through reordering according to a specific random pattern and can also be performed according to a specific pattern.
  • a rule may be generated and applied based on a corresponding column or row index and a rule may also be generated and applied regardless of a column or row index.
  • cell-specific information such as a cell ID.
  • the configuration of the interleaver of each of the OFDM symbols is defined by the number of rows and the number of columns, the number of rows and the number of columns of each symbol interleaver can be set to be equal and can also be set to be different for given purposes.
  • the number of columns of the block interleaver of each OFDM symbol can be defined in association with the number of mini-CCEs, allocated to the OFDM symbol, of all control channels or CCEs.
  • the number of columns can also be defined using a given rule for a given purpose.
  • a basic row size can be set based on the total number of mini-CCEs input to the block interleaver and a different row size from the basic row size can be set based on a preset rule of reordering or permutation of each column.
  • the method for performing intra-column permutation and the method for setting the number of rows and the number of columns taking into consideration characteristics and requirements of a specific channel can be used for each type of control channel by setting a specific value and pattern based on the purposes described above.
  • Mathematical Expression 35 represents an example method for determining the number Cj of columns of an interleaver of each OFDM symbol when interleaving is applied only to a PDCCH and the following Mathematical Expression 36 represents an example method for determining the number Cj of columns of an interleaver of each OFDM symbol when a PDCCH and a PHICH are interleaved together.
  • Mathematical Expression 36 represents the number of mini-CCEs of a kth PHICH transmitted through the ith OFDM symbol.
  • Mathematical Expression 37 represents an example method for determining the number R 1 of rows of an interleaver of each OFDM symbol when interleaving is applied only to a PDCCH and the following Mathematical Expression 38 represents an example method for determining the number Rj of rows of an interleaver of each OFDM symbol when a PDCCH and a PHICH are interleaved together.
  • Mathematical Expression 38 represents an example method for determining the number Rj of rows of an interleaver of each OFDM symbol when a PDCCH and a PHICH are interleaved together.
  • Mathematical Expression 38 represents the number of mini-CCEs of a PHICH transmitted through the ith OFDM symbol.
  • N ⁇ lc ⁇ H C f can be determined as in the following Mathematical Expression 39.
  • SF in Mathematical Expression 39 represents a spreading factor
  • RPF represents the number of repetitions of the PHICH
  • N UL VRB represents the number of uplink
  • resource blocks allocated to a system bandwidth.
  • the value of N 1 UL VRB can vary according to the system bandwidth.
  • the positions of resources through which a downlink PHICH is transmitted can be determined according to downlink resource blocks through which each terminal transmits data. For example, in the case where the system bandwidth is 5MHz, the number of uplink resource blocks is 25 and the maximum value "25" can be set as N UL r ⁇ g since the downlink PHICH needs to indicate any resource block through
  • N UL _ VRB can varv accO rding to the system bandwidth
  • the number of mini-CCEs of a PHICH transmitted through the ith OFDM symbol can be determined using N UL vm as a variable as in Mathematical Expression 39.
  • interleaving can be implemented using a method in which specific control channels are fixed to specific positions (or specific row/column indices) in the interleaver or a method in which, when a symbol sequence is input to the interleaver, the order of symbols of the input symbol sequence is changed according to an arbitrary method in order to accomplish the purposes described above.
  • FIG. 40 illustrates an example method for performing interleaving for each OFDM symbol using a block interleaver according to an embodiment of the invention.
  • a column reordering or permutation pattern for an individual block interleaver to be applied to each OFDM symbol can be defined by dividing a block interleaver 70 that is virtually provided for all OFDM symbols into groups of columns to apply an individual block interleaver to each OFDM symbol.
  • the column reordering or permutation pattern can be defined as a random pattern as described above and can also be defined as a pattern according to a specific rule.
  • Mathematical Expression 40 represents an example method for defining the number C of columns when respective block interleavers of OFDM symbols are regarded as one block interleaver 70.
  • the number of columns C can be represented by the sum of the respective numbers of columns of OFDM symbols calculated through Mathematical Expression 35 or 36.
  • the numbers of columns of respective block interleavers 71, 72, and 73 of the OFDM symbols can be defined as Cl, C2, and C3.
  • the respective numbers of columns of the block interleavers of the OFDM symbols can be set according to a ratio of the numbers of physical mini-CCEs that can be used to transmit control channels for the OFDM symbols.
  • the respective numbers of columns of the block interleavers can be set to other values for other purposes. For example, "C" of the virtual block interleaver in FIG.
  • the numbers of rows of the block interleavers applied respectively to the OFDM symbols can be defined to be different when an arbitrary one of different types of control channels is mapped only to a specific OFDM symbol and can be alternatively defined to be equal by applying pruning.
  • mini-CCEs not used in individual OFDM symbols can be incorporated into corresponding block interleavers so that they are interleaved by the block interleavers, and the values of Rl, R2, and R3 can be determined taking into consideration the interleaving of such mini-CCEs.
  • FIG. 41 illustrates an example method in which two or more control channels are interleaved together and are then multiplexed and transmitted according to an embodiment of the invention.
  • FIG. 41 illustrates an example where two control channels, a PDCCH and a PHICH, are interleaved together.
  • divided interleavers can be constructed according to the same method as described above with reference to FIG. 40.
  • mini-CCEs of a PHICH can be defined according to the characteristics of the block interleaver in order to optimize frequency diversity.
  • First symbol mini-CCEs 80, 83, and 86, second mini-CCEs 81, 84, and 87, and third mini-CCEs 82, 85, and 88 of the PHICHs are sequentially input (or written) to a first row 89 of a block interleaver.
  • the three mini-CCEs of each PHICH can be interleaved in different block interleavers. Accordingly, the method can obtain effects of uniform distribution and multiplexing over a specific or entire range of column indices.
  • Mathematical Expression 41 represents an example method for column-wise permutation or reordering of a block interleaver of an ith OFDM symbol in an interleaving operation of a block interleaver constructed using the above method.
  • P R"- R'
  • Mathematical Expression 41 represents an example where three block interleavers, which are constructed with respective sizes of R"xCl, R"xC2, and R"xC3, are applied to three OFDM symbols, respectively, as shown in FIG. 40.
  • the same number of rows R ⁇ ⁇ is applied to each block interleaver.
  • Cl, C2, and C3 may be equal to or different from each other when a block interleaver is individually applied to each OFDM symbol.
  • Some of the variables may have a different value and the value of each variable may match the number of columns of the interleaver of each individual OFDM symbol and may also be defined based on a specific pattern or a random value.
  • a value used in association with each column of an OFDM symbol interleaver in Mathematical Expression 41 represents a column index that is increased by 1 every column. However, a value not associated with the column index can also be applied to each column.
  • the number R of rows of the block interleaver be set to a prime number.
  • the determined value (R ⁇ ) of R is a prime number, it can be immediately determined to be the number of rows R (R") of the block interleaver.
  • different offsets can be allocated to column indices of respective block interleavers of OFDM symbols so that mini-CCEs of CCEs are input in a distributed manner to the block interleavers of the OFDM symbols and mini-CCEs are also distributed over all OFDM symbols when interleaving is performed for each OFDM symbol in order to reliably provide frequency domain diversity to CCEs.
  • Mathematical Expression 42 represents an example method for allocating different offsets to column indices of respective block interleavers of OFDM symbols.
  • an interleaver can be commonly used for multiple cells while mapping can be performed taking into consideration cell-specific information, for example a cell identifier (ID), in order to minimize inter-cell interference in multi-cell environments.
  • ID cell identifier
  • interleaver elements can be output from the interleaver after the elements are cyclically shifted using cell-specific information such as a cell ID for each cell after a block interleaving process is completed.
  • cell-specific information such as a cell ID for each cell
  • the interleaver elements cyclically shifted using cell-specific information such as a cell ID for each cell can also be mapped to physical resources.
  • an output sequence of an interleaver can be directly mapped to physical resource elements without shifting a random pattern generated using the interleaver and, for a cell having a shift factor of "10", the output sequence of the interleaver can be mapped to physical resource elements after cyclically shifting elements in a random pattern in the interleaver output sequence by 10. That is, a cyclic shift method is applied such that elements interleaved on a column basis are mapped to physical resources after a cyclic shift is applied to an interleaving pattern of all elements of the interleaver using information such as a cell ID for each cell, unlike the previously described method.
  • the invention may also provide a method in which, before all mini-CCEs of CCEs used for control channel transmission are input to the interleaver, the mini-CCEs are divided according to OFDM symbols used for control channel transmission and interleaving common to a corresponding cell is performed on mini-CCEs that are to be mapped to resource element groups of each OFDM symbol.
  • a mini-CCE sequence input to the block interleaver may be constructed in a format in which various control channels are multiplexed.
  • Mathematical Expression 43 represents an example method of representing an algorithm that can implement virtual interleaving for an interleaving operation using the block interleaver described above.
  • ⁇ j represents an output position index of a mini-CCE corresponding to an input position index j at an ith OFDM symbol interleaver.
  • This value may represent a position index in a block interleaver allocated for virtual interleaving.
  • values calculated using the same method as those used when an individual block interleaver of each ith OFDM symbol is implemented can be used.
  • base station may perform various operations for communication with terminals in a network including a number of network nodes.
  • base station may be replaced with another term such as “fixed station”, “Node B”, “eNode B (eNB)", or “access point”.
  • terminal may also be replaced with another term such as "user equipment (UE)", “mobile station (MS)”, or “mobile subscriber station (MSS)”.
  • UE user equipment
  • MS mobile station
  • MSS mobile subscriber station

Abstract

L'invention porte sur une méthode de transmission d'un canal de contrôle de liaison descendante dans un système de communication mobile et sur une méthode de mise en correspondance du canal de contrôle avec des ressources physiques utilisant un entrelaceur de blocs. Pour transmettre le canal de contrôle de liaison descendante dans le système de communication mobile, on module des bits d'information pour produire un ou des symboles de modulation selon un schéma de modulation spécifique, les symboles de modulation étant entrelacés à l'aide d'un entrelaceur de blocs, et les symboles modulés entrelacés étant mis en correspondance avec des éléments de ressources attribués pour la transmission d'au moins un canal de contrôle dans une sous-trame, ce qui permet de transmettre le ou lesdits canaux de contrôle.
PCT/KR2008/002093 2007-04-27 2008-04-14 Méthode de transmission d'un canal de contrôle de liaison descendante dans un système de communication mobile et méthode de mise en correspondance du canal de contrôle avec des ressources physiques en utilisant un entrelaceur de blocs dans un système de communication mobile WO2008133415A1 (fr)

Priority Applications (11)

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US12/451,093 US8254245B2 (en) 2007-04-27 2008-04-14 Method for transmitting downlink control channel in a mobile communications system and a method for mapping the control channel to physical resource using block interleaver in a mobile communications system
BRPI0810979-6A BRPI0810979A2 (pt) 2007-04-27 2008-04-14 Método para transmissão de canal de controle em sistema de comunicação móvel
GB0919205A GB2461464B (en) 2007-04-27 2008-04-14 Transmitting a downlink control channel in a mobile communication system and mapping the control channel to a physical resource using a block interleaver
JP2010506038A JP4976543B2 (ja) 2007-04-27 2008-04-14 移動通信システムにおいて下り制御チャネルを伝送する方法並びにブロックインターリーバを用いて制御チャネルを物理リソースにマッピングする方法
US13/554,914 US8638654B2 (en) 2007-04-27 2012-07-20 Method for transmitting downlink control channel in a mobile communication system and a method for mapping the control channel to physical resource using block interleaver in a mobile communication system
US13/928,148 US9055580B2 (en) 2007-04-27 2013-06-26 Method for transmitting downlink control channel in a mobile communications system and a method for mapping the control channel to physical resource using block interleaver in a mobile communications system
US14/106,239 US9049710B2 (en) 2007-04-27 2013-12-13 Method for transmitting downlink control channel in a mobile communications system and a method for mapping the control channel to physical resource using block interleaver in a mobile communications system
US14/703,437 US9414376B2 (en) 2007-04-27 2015-05-04 Method for transmitting downlink control channel in a mobile communications system and a method for mapping the control channel to physical resource using block interleaver in a mobile communications system
US15/207,257 US9609645B2 (en) 2007-04-27 2016-07-11 Method for transmitting downlink control channel in a mobile communications system and a method for mapping the control channel to physical resource using block interleaver in a mobile communications system
US15/437,659 US10142979B2 (en) 2007-04-27 2017-02-21 Method for transmitting downlink control channel in a mobile communication system and a method for mapping the control channel to physical resource using block interleaver in a mobile communications system
US16/158,671 US10582487B2 (en) 2007-04-27 2018-10-12 Method for transmitting downlink control channel in a mobile communication system and a method for mapping the control channel to physical resource using block interleaver in a mobile communications system

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US91462207P 2007-04-27 2007-04-27
US60/914,622 2007-04-27
US94511107P 2007-06-20 2007-06-20
US60/945,111 2007-06-20
US95586907P 2007-08-14 2007-08-14
US60/955,869 2007-08-14
US98315607P 2007-10-26 2007-10-26
US60/983,156 2007-10-26
US98360007P 2007-10-30 2007-10-30
US60/983,600 2007-10-30
KR1020070123605A KR20080096351A (ko) 2007-04-27 2007-11-30 통신 시스템에서의 제어 채널을 전송하는 방법
KR1020070123603A KR20080096350A (ko) 2007-04-27 2007-11-30 다수 셀 환경에서 통신 시스템에서의 하향링크 제어 채널을전송하는 방법 및 통신 시스템에서, 블록 인터리버를이용하여 가상자원을 물리자원으로 매핑하는 방법
KR10-2007-0123605 2007-11-30
KR10-2007-0123603 2007-11-30
KR1020080002201A KR20080096356A (ko) 2007-04-27 2008-01-08 다수 셀 환경의 무선 통신 시스템에서 하향링크 제어채널을전송하는 방법
KR10-2008-0002201 2008-01-08
KR1020080006927A KR20080096358A (ko) 2007-04-27 2008-01-23 직교주파수분할다중화 통신 시스템에서 하향링크제어채널을 전송하는 방법
KR10-2008-0006927 2008-01-23

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US13/554,914 Continuation US8638654B2 (en) 2007-04-27 2012-07-20 Method for transmitting downlink control channel in a mobile communication system and a method for mapping the control channel to physical resource using block interleaver in a mobile communication system

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