KR20090056102A - Method and apparatus of resource allocation scheme for interleaver in ofdma wireless telecommunication system - Google Patents

Abstract

A method and an apparatus for arranging resources for an interleaver in an orthogonal frequency division multiplexing access are provided to secure the performance of the whole control channel resource regardless of the quantity and the position of the fixed resources by suggesting a fixed position resource processing method preferentially for securing frequency diversity when performing the interleaver. A mini-CCE is comprised according to a bandwidth of a system, the number of antenna ports, and the determined PCFICH and the indexing is performed(701). A position of PHICH of PCFIHC designated in a cell is determined(702). If the index is determined after interleaving, a fixing position control channel is de-interleaved(704). The n mini-CCEs is comprised of the PDCCH as a small index order for the remaining mini-CCE except the i index determined in the PCFICH and PHICH(706). The Interleaver is performed for the input index of all interleavers(707). The mini-CCE arranged in the output of the interleaver is mapped according to the time priority(708).

Description

Resource allocation method and apparatus for interleaver in orthogonal frequency division multiple access system {METHOD AND APPARATUS OF RESOURCE ALLOCATION SCHEME FOR INTERLEAVER IN OFDMA WIRELESS TELECOMMUNICATION SYSTEM}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for resource allocation of physical channels in a communication system using Orthogonal Frequency Division Multiplexing ("OFDM"). In particular, a control channel resource and a frequency diver to be allocated to a specific location The present invention relates to a method for arranging heterogeneous downlink control channel resources to be allocated to an arbitrary location considering a city, a transmission and reception apparatus, and a method.

The OFDM transmission method is a method of transmitting data using a multi-carrier, that is, a multi-carrier, in which a plurality of multi-carriers in which symbol strings are serially input in parallel and each of them are orthogonal to each other In other words, it is a type of multi-carrier modulation that modulates and transmits a plurality of sub-carrier channels.

Such a system using a multicarrier modulation scheme was first applied to military high frequency radios in the late 1950s, and the OFDM scheme of overlapping a plurality of orthogonal subcarriers began to develop in the 1970s, but the implementation of orthogonal modulation between multicarriers was implemented. Since this was a difficult problem, there was a limit to the actual system application. However, in 1971, Weinstein et al. Announced that modulation and demodulation using the OFDM scheme can be efficiently processed using a Discrete Fourier Transform (DFT). Also known is the use of guard intervals and the insertion of cyclic prefixes (CPs) into the guard intervals to further mitigate the adverse effects of the system on multipath and delay spread. Was reduced.

Thanks to these technological advances, OFDM technology is used for digital audio broadcasting (DAB) and digital video broadcasting (DVB), wireless local area network (WLAN), and wireless asynchronous transmission mode (WATM). It is widely applied to digital transmission technology such as wireless asynchronous transfer mode. In other words, the OFDM method is not widely used due to hardware complexity, and recently, various digital signal processing techniques including fast Fourier transform (FFT) and inverse fast Fourier transform (IFFT) have been introduced. It is made possible by the development.

The OFDM scheme is similar to the conventional frequency division multiplexing (FDM) scheme, but has a characteristic of obtaining optimal transmission efficiency in high-speed data transmission by maintaining orthogonality among a plurality of tones. In addition, the OFDM scheme has good frequency usage efficiency and is strong in multi-path fading, so that an optimum transmission efficiency can be obtained in high-speed data transmission.

Another advantage of the OFDM scheme is that the frequency spectrum is superimposed so that it is efficient to use the frequency, is strong in frequency selective fading, is strong in multipath fading, and intersymbol interference (ISI) using a guard interval. It is possible to reduce the effects of symbol interference, to easily design an equalizer structure in hardware, and to be strong in impulsive noise, and thus it is being actively used in a communication system structure.

The factors that hamper high-speed, high-quality data services in wireless communication are largely due to the channel environment. In the wireless communication, the channel environment includes a Doppler according to power change, shadowing, movement of the terminal, and frequent speed change of a received signal caused by fading in addition to additive white Gaussian noise (AWGN). Doppler), interference with other users and multi-path signals are often changed. Therefore, in order to support high-speed and high-quality data services in wireless communication, it is necessary to effectively overcome the above-mentioned obstacles in the channel environment.

In the OFDM scheme, a modulated signal is located in a two-dimensional resource composed of time and frequency. The resources on the time axis are divided into different OFDM symbols and they are orthogonal to each other. The resources on the frequency axis are divided into different tones and they are also orthogonal to each other. That is, in the OFDM scheme, if a specific OFDM symbol is designated on the time axis and a specific tone is designated on the frequency axis, one minimum unit resource may be indicated, which is called a resource element (hereinafter, referred to as a RE). Different REs have orthogonality to each other even though they pass through a frequency selective channel, so that signals transmitted to different REs may be received at a receiving side without causing mutual interference.

A physical channel is a channel of a physical layer that transmits modulation symbols that modulate one or more encoded bit streams. In Orthogonal Frequency Division Multiple Access (OFDMA) systems, a plurality of physical channels are configured and transmitted according to the purpose of the information string to be transmitted or the receiver. The transmitter and the receiver must promise in advance which RE to arrange and transmit one physical channel. The rule is called mapping (hereinafter, referred to as "mapping").

The mapping can be changed according to the operation characteristics of the physical channel. When the transmitter is aware of the state of the receiving channel and the physical channel is mapped using the scheduler to improve the transmission efficiency of the system, the channel state is similar to that of the RE. If one physical channel is placed in a set and the physical channel is mapped for the purpose of lowering the reception error rate while the transmitter does not recognize the state of the receiving channel, one of the REs is expected to be very different. It is desirable to arrange physical channels.

The former method is suitable for transmitting data for a user as long as it is not sensitive to latency. The latter method is mainly used for data or control information for a user as long as it is sensitive to latency, or for data transmitted to multiple users. It is suitable for transmitting control information. The latter scheme uses resources with different channel states to obtain diversity gain. If one of the OFDM symbols is mapped to a subcarrier as far as possible on the frequency axis, frequency diversity gain can be obtained.

1 illustrates a subframe structure in a Long Term Evolution (LTE) system to which the present invention is applied.

One resource block ("RB") 101 is composed of 12 tones arranged on the frequency axis and 14 OFDM symbols 114 arranged on the time axis. RB 1 101 represents a first RB, and FIG. 1 shows a bandwidth consisting of K RBs up to RB K 102. The 14 OFDM symbols on the time axis constitute one subframe 113 and become the basic unit of resource allocation on the time axis. One subframe 113 has a length of 1 ms and consists of two slots 112.

The reference signal (hereinafter referred to as "RS") is a signal promised to the base station transmitting to the terminal so that the terminal can make a channel estimation. The RS0 121, the RS1 122, the RS2 123, and the RS3 124 Denotes RSs transmitted from antenna port 0, antenna port 1, antenna port 2, and antenna port 3, respectively. If the number of antenna ports is 1 or more, this means using a multi-antenna. If only one transmit antenna port is used, only RS0 121 is used for data transmission, RS1 122 is not used for transmission, and RS2 123 and RS3 124 are used for data or control signal symbol transmission. Also, if two transmit antenna ports are defined, RS0 121 and RS1 122 are used for data transmission, and RS2 102 and RS3 103 are used for data or control signal symbol transmission.

The absolute position of the RE where the RS is placed on the frequency axis is set differently for each cell, but the relative spacing between the RSs remains constant. That is, the RS of the same antenna port maintains a 6RE interval, and the interval between RS0 121 and RS1 122 maintains a 3RE interval between the RS2 123 and the RS3 124. The reason why the absolute position of the RS is set differently for each cell is to avoid collision between cells of the RS.

The control channel signal is located at the head of one subframe on the time axis. In FIG. 1, reference numeral 111 illustrates an area where a control channel signal can be located. The control channel signal may be transmitted over L OFDM symbols located at the head of the subframe. L may have a value of 1,2 or 3 (111, 115). If the amount of control channels is small enough to transmit a control channel signal with one OFDM symbol, only one leading OFDM symbol is used for transmission of the control channel signal (L = 1) and the remaining 13 OFDM symbols transmit data channel signals. Used for When the control channel signal consumes two OFDM symbols, only the two OFDM symbols at the head are used for control channel signal transmission (L = 2), and the remaining 12 OFDM symbols are used for data channel signal transmission. If the amount of control channel signals is large enough to use all three OFDM symbols, the first three OFDM symbols are used for the control channel signal transmission (L = 3) and the remaining 11 OFDM symbols are data channel signals. Used for transmission

The reason for placing the control channel signal at the head of the subframe is to determine whether to perform the data channel reception operation by first receiving the control channel signal and recognizing whether the data channel signal transmitted to the terminal is transmitted. Therefore, if there is no data channel signal transmitted to the self, it is not necessary to receive the data channel signal, thus saving the power consumed in the data channel signal receiving operation.

The downlink control channel defined in the LTE system includes a Physical Control Format Indicator Channel (PCFICH), a Physical Hybrid ARQ Indicator Channel (PHICH), and a Packet Data Control Channel (PDCCH).

PCFICH is a physical channel for transmitting CCFI (Control Channel Format Indicator) information. CCFI is information consisting of 2 bits to inform L. Since the CCFI must be received first to know and receive the number of symbols allocated to the control channel, the PCFICH is a channel to be first received in a subframe by all terminals except when a fixed downlink resource is allocated. Since the L is not known until the PCFICH is received, the PCFICH must be transmitted in the first OFDM symbol. The PCFICH channel is transmitted to a predetermined fixed position for each cell, and the receiver is also received without the position information.

PHICH is a physical channel for transmitting downlink ACK / NACK signal. The terminal receiving the PHICH is a terminal in progress of data transmission in the uplink. Therefore, the number of PHICHs is proportional to the number of terminals that are performing data transmission in uplink. The PHICH is transmitted in the first OFDM symbol (LPHICH = 1) or over three OFDM symbols (LPHICH = 3). LPHICH is a parameter defined for each cell, and is introduced to adjust the PHICH because it may be difficult to transmit the PHICH with only one OFDM symbol when the cell size is large. Configuration information of PHICH (amount of symbol used, location, etc.) is informed to the UE through PBCH. The PHICH channel is also transmitted to the designated location for each cell.

The PDCCH is a physical channel for transmitting data channel allocation information or power control information. The PDCCH may set a channel coding rate differently according to a channel state of a receiving terminal. Since PDCCH uses Quadrature Phase Shift Keying (QPSK) as a modulation method, it is necessary to change the amount of resources used by one PDCCH to change the channel coding rate. A high channel coding rate is applied to a terminal having a good channel state to reduce the amount of resources used. On the other hand, even if the amount of resources used is increased to the terminal in a bad channel state, the reception is possible by applying a high channel coding rate. The amount of resources consumed by an individual PDCCH is determined in units called control channel elements (hereinafter, referred to as "CCEs"). In addition, the CCE is composed of a plurality of mini-CCE. The mini-CCE of the PDCCH is placed in a control channel resource after going through an interleaver to guarantee diversity.

Mini-CCE is a basic unit of control channel resources constituting CCE, PCFICH and PHICH. PCFICH and PHICH use a certain amount of resources to determine the amount of resources in a set of mini-CCE to facilitate the multiplexing and transmission diversity with the PDCCH. One PCFICH is configured using NPCFICH mini-CCEs and one PHICH is configured using NPHICH mini-CCEs. If NPCFICH = 4 and NPHICH = 3, this means that PCFICH uses 16 REs and PHICH uses 12 REs.

PHICH applies Code Domain Multiplexing (CDM) technique to multiplex multiple ACK / NACK signals. Four PHICH signals are CDMed in one mini-CCE, and are arranged in such a way that they are repeated as many as the number of NPHICHs to be as far apart as possible on the frequency axis in order to obtain frequency diversity gain. Therefore, four or fewer PHICH signals can be configured by using NPHICH mini-CCEs. In order to configure more than four PHICH signals, another NPHICH mini-CCE should be used.

The physical channel is mapped to the mini-CCE of the assigned control channel and performs interleaving to obtain a frequency diversity gain. Interleaving is performed for the mini-CCE of the control channel. The output of the interleaver of the control channel prevents inter-cell interference caused by using the same interleaver between cells, while mini-CCEs of the control channel allocated across one or more symbols are far from the frequency axis. You should be able to gain diversity gain apart. In addition, mini-CCEs constituting the same channel should be equally distributed among symbols for each channel.

The present invention provides a method and apparatus for simultaneously satisfying the arrangement of fixed position resources and unfixed position resources in guaranteeing frequency diversity and inter-symbol dispersion effect by applying an interleaver of a control channel.

According to an embodiment of the present invention, a method of transmitting control information in a communication system using an orthogonal frequency division multiple access method includes interleaving a mini-CCE index in units of total mini-CCEs, and interleaving the mini-CCEs. Assigning a corresponding fixed position control channel to a mini-CCE index preset to assign a fixed position control channel to a specific mini-CCE, and sequentially assigning a non-fixed control channel to the remaining mini-CCE indexes; And mapping the position control channel and the non-fixed control channel to the allocated mini-CCE.

In addition, a method of transmitting control information in a communication system using an orthogonal frequency division multiple access scheme according to another embodiment of the present invention, in consideration of interleaving performed in units of all mini-CCEs, includes a specific mini among all mini-CCEs. Performing a pre-interleaving on the fixed position control channel so that the fixed position control channel is allocated; and totally mini-CCE interleaving the pre-interleaved fixed position control channel and the non-fixed position control channel. Allocating interleaved control channels to a corresponding mini-CCE, and mapping and transmitting the fixed position control channel and the non-fixed control channel to the allocated mini-CCE.

When the effect obtained by the typical thing of the invention disclosed below is demonstrated briefly, it is as follows.

According to the present invention, when a base station performs interleaver in transmitting control information for transmission and reception to a terminal in a wireless communication system, the present invention proposes a method of first processing a fixed location resource to ensure frequency diversity, thereby providing an amount and location of a fixed resource. Regardless, the performance of the entire control channel resource can be guaranteed.

In addition, in the configuration of the downlink control channel, the mini-CCE of the PDCCH channel, which is a control channel allocated to an unfixed position, may ensure equal distribution among symbols for each PDCCH.

Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle of the embodiment of the present invention. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to intention or custom of a user or an operator. Therefore, the definition should be made based on the contents throughout the specification.

In the following description, the LTE system is described as an example, but the present invention can be applied to other wireless communication systems to which base station scheduling is applied without any addition or subtraction.

Among the downlink control channels, the PCFICH and the PHICH, which are fixed location channels, should be arranged at a predetermined location that guarantees frequency diversity for each cell during mini-CCE mapping. Since the PDCCH performs an interleaver during mini-CCE mapping, which is a physical resource, the PDCCH is a fixed location channel, and may be disposed over one or several OFDM symbols according to a system configuration environment. Between the mini-CCEs constituting the PDCCH disposed in each OFDM symbol, frequency diversity must be guaranteed after the interleaver is performed, and the mini-CCEs must be uniformly distributed for each symbol. In addition, similar performance must be guaranteed between each PDCCH. PHICH among fixed location resources is a channel whose amount may change over time. Therefore, the index of the mini-CCE changes according to the amount and location of the fixed location channel resources, and the length of the interleaver changes. In this case, since the interleaver result of the PDCCH changes, it is difficult to guarantee the performance. Therefore, to solve this problem, the present invention proposes a method of guaranteeing the performance of both the fixed position channel and the non-fixed position channel by adding a simple preprocess before the interleaver.

2 is a diagram illustrating a configuration of a control channel in mini-CCE units according to an embodiment of the present invention.

2 shows a mini-CCE structure when four antennas are used and L = 3 and LPHICH = 3. In the case of L is 1, 2 and LPHIHC is 1, the same method can be applied. In the present patent, the present invention is described through the above example and can be applied regardless of the antenna configuration. The RB # 0 202 is composed of 12 REs as described above, and the mini-CCEs 201 and 214 are composed of four REs except RS among successive REs in the frequency axis. Thus, symbol # 0 and symbol # 1 (212) are composed of mini-CCE 201 with 6 RE intervals including 2 RSs, and symbol # 2 (212) is mini-CCE (214 with 4 consecutive RE intervals. ) Is configured. The index of the mini-CCE for the interleaver starts at a low frequency for all control symbols, starts with index 0 of the mini-CCE 201 of symbol # 0, and increases in symbol order as shown in FIG. The index of the mini-CCE 213 of symbol # 2 is increased to two. The incremented index in symbol order is assigned # 3 to the fifth RE of the lower frequency symbol # 2, followed by a return to symbol # 0 and incremented as before. The position of the RS of FIG. 2 is circulated along the frequency axis according to the base station and the present invention is equally applicable to such a cycle.

The size of the interleaver is applied differently according to the number of mini-CCEs of the symbols allocated to the control channel. When the index is configured using all mini-CCEs as shown in FIG. 2, the size of the total interleaver is the sum of the number of mini-CCEs of each OFDM symbol. However, among the control channels of the LTE system, there is a channel to be transmitted to a designated location without applying the interleaver effect, and PCFICH and PHICH correspond to this. In this case, the size of the interleaver is also changed, and FIG. 3 shows an example. 3 is an example of the case where the PCFICH must be located in the mini-CCE # 0 201 of FIG. 2 and the PHICH channel must be located in the mini-CCE # 1 in comparison with FIG. In this case, as in 311, the index of the mini-CCE is indexed except for 301 and 302, which does not need the interleaver, and thus the size of the interleaver is reduced.

4 illustrates a resource structure and an interleaver result to which the present invention is applied.

The control channel transmitted by one base station may be classified into a fixed position control channel 401 which is positioned in advance in frequency and time and an unfixed control channel 402 which is not predetermined. In the LTE system, PCFICH and PHICH of 411 and 412 correspond to a fixed position control channel, and PDCCH of 413 and 414 of FIG. 4 correspond to an unfixed control channel. The fixed control channel should be mapped to a predetermined position of the control symbol as indicated by reference numeral 421, 422 and 432, and the non-fixed control channel performs the interleaver 423 and the time and total control region as indicated by reference numeral 424. It should be distributed over frequency (431, 433, 434). This is to allow the power used for the PDCCHs to be distributed over the entire bandwidth. Distribution on the frequency axis can also achieve diversity gain. 5 shows an example in which two PDCCHs 501 and 502 are distributed. One PDCCH consists of nine mini-CCEs in the example. In the case of PDCCH 1 501, it can be seen that nine mini-CCEs are uniformly distributed among symbols in consideration of fixed allocation resources (521). On the other hand, in the case of PDCCH 2 502, it can be seen that there is no mini-CCE allocated after the interleaver in symbol # 0, and too many mini-CCEs are allocated to symbol # 2. This is because the size of the interleaver described above is affected by the fixed control channel. 2 and 3, when the size of the interleaver changes, the interval between the indices is different. In the case of Figure 2, the interval between mini-CCE index 2 and 4 is one mini-CCE and the interval between 2 and 7 is three mini-CCE. On the other hand, in FIG. 3, the spacing between 2 and 4 is still one mini-CCE, but the spacing between 2 311 and 7 312 is two mini-CCEs. This difference is greater if there are contiguous fixed allocation channels. When indexing is performed by the fixed allocation channel like this, even though the output of the interleaver guarantees frequency diversity, it is difficult to guarantee frequency diversity because the difference between the index interval and the mini-CCE interval is different. Will change with each other.

Therefore, in the present invention, when there are both the fixed position control channel and the non-fixed control channel, the interleaver size is fixed with all possible resources, that is, the total number of mini-CCEs, without changing the interleaver size, thereby satisfying the interleaver result of the non-fixed control channel. We propose a scheme, a receiver and a transmitter structure that can pre-process the position control channel and map it to the designated position irrespective of the interleaver result. This makes the interleaver result of the non-fixed position control channel large in dispersion effect in time and frequency without being affected by the position and amount of the fixed position control channel. Hereinafter, specific embodiments of the structure proposed by the present invention will be described.

(1) First embodiment

6 illustrates a process of the first embodiment proposed in the present invention. The preprocessing method proposed in the first embodiment is a method of performing an inverse interleaver on a position of a fixed position control channel and inserting it into an input of an interleaver. Since the proposed scheme uses a fixed interleaver size, the size of the interleaver is the sum of the mini-CCEs of the control symbols, and the control control channel structure 601 is used to index all the mini-CCEs with time priority.

As described above, the fixed position control channel is divided into a PCFICH 611 and a PHICH 612. The remaining mini-CCEs are allocated to the PDCCH 613. In the fixed position control channel, the mapping position after the interleaver is already determined. In FIG. 6, the first mini-CCE 614 of the PCFICH should be located at index 0 and the first mini-CCE of the PHICH should be located at the fourth index. Reference numeral 612 denotes a block for deriving an input value using an output position value. This process can be obtained through the reverse interleaving process. Through this process, the position of the first mini-CCE of the PCFICH is changed to the interleaver input order for the fourth time, and the position of the first mini-CCE of the PHICH is changed to the input of the 0th interleaver. After changing the position of the fixed position control channel in this way, the remaining consecutive n mini-CCEs are bundled in order to configure a PDCCH (622). It is applied regardless of the number of mini-CCEs constituting the PDCCH. The rearranged mini-CCE becomes the input 631 of the interleaver. After that, the interleaver 632 is performed on all mini-CCEs. At this time, the base station maps the mini-CCE of the control symbol in the indexing order by using the order of the output 633. Therefore, the position of the positioned mini-CCE can be arranged to the desired point after the interleaver. As shown in FIG. 6, when the output order is 4, 20, 1, 9, 0, 18, ..., the base station selects the mini-CCE channel, which is the fourth interleaver input, according to the indexing order, and the 0-th mini-CCE. In operation 642, the mini-CCE channel, which was the 20th interleaver input, is mapped to the first mini-CCE, and the mini-CCE, which is the 0th interleaver input, is mapped to the second mini-CCE 644. In this mapping, the mini-CCE, which was a fixed position control channel, is placed at a designated position (642, 643). Since the indexing of the mini-CCE is not changed and fixed, the interleaver has the greatest dispersion effect. This can be applied regardless of the type of interleaver.

7 is a flowchart illustrating a transmitter structure proposed in the first embodiment. First, in order to configure the control channel, the mini-CCE is configured according to the bandwidth of the system, the number of antenna ports used, and the determined PCFICH size in step 701 and indexing is performed as described above. In step 702, the position of the PHICH of the PCFIHC assigned to the cell is determined. If the position is determined, i`, which is the position index value after the interleaver, is derived. If the index value after the interleaver is determined, the reverse interleaver is performed on the fixed position control channel in step 704. When the index i having performed the deinterleaver is calculated, all mini-CCEs are listed in the order of the i-index as in step 705. In step 706, n mini-CCEs are configured as PDCCHs in small index order for the remaining mini-CCEs except for i-indexes defined in PCFICH and PHICH. In step 707, the interleaver is performed on the input indexes of all the interleavers. In step 708, the mini-CCE disposed at the output of the interleaver is mapped to the control channel in time priority order. In step 709, the control channel is transmitted to the terminal.

(2) Second embodiment

8 shows a process of a second embodiment proposed in the present invention. The preprocessing method proposed in the second embodiment removes the index corresponding to the address of the fixed position control channel before the interleaver based on the precomputed interleaver result, thereby avoiding the influence of the position and the amount of the fixed position resource. We propose a transmission and reception scheme.

The structure of the control channel used in the second embodiment is the same as that of the first embodiment and is the same as that of the reference numeral 801. In the present embodiment, the input index 811 and the output index 813 are first calculated using the interleaver controller 812. However, interleaving did not actually occur, it is the process of calculating the index. The position of the fixed position control channel is already determined as in the first embodiment, and its position indices are also known (821, 824). Then, the index of the fixed position control channel is removed from the output index 813 of the pre-calculated interleaver (826, 827, 825). Except for the index thus removed, the remaining indexes 830 are rearranged in order. The PDCCH 828 is arranged for the n mini-CCEs in order of the remaining indexes (829). After the interleaver, the fixed position index is removed from the index, so it is randomly removed and desired performance can be obtained even if the remaining resources are arranged consecutively. The arranged PDCCH is interleaved as follows in the actual mapping process. As shown in FIG. 8, when the remaining indexes 830 are in the order of 20, 1, 9, 18, ..., the base station calculates the address of the mini-CCE and arranges the mini-CCE. That is, the first index is 20, and therefore, the first mini-CCE of the PDCCH is placed in the 20th mini-CCE of the original control symbol. Then, since the second index is 1, the mini-CCE of the second PDCCH is placed at the first mini-CCE position 834 of the entire control symbol. The fixed position control channel maps to a predetermined position. When mapping the entire mini-CCE, the same effect as in the first embodiment can be obtained, and the dispersion effect of the mini-CCE in the PDCCH has the same performance as in the first embodiment.

9 is a diagram illustrating a transmission process of control channel resource allocation according to the second embodiment of the present invention.

In step 901, the mini-CCE is configured according to the bandwidth of the system, the number of antenna ports used, and the value of the determined PCFICH, and time-indexing is performed as described above. In step 902, the designated positions of the mini-CCEs of the PCFICH and the PHICH are determined. Then, in step 903, the index of the interleaver output is derived and stored using the size of the interleaver. Thereafter, the index corresponding to the location of the mini-CCE of the PCFICH and the PHICH is removed from the interleaver output index stored in step 904. In step 905, n mini-CCEs are sequentially tied to the remaining indexes removed in step 904 to form a PDCCH channel. In step 906, the interleaver output index is used as an address to perform interleaving of the mini-CCE of the PDCCH and map to the control symbol. In step 907, the PCFICH and the PHICH, which are fixed position control channels, are mapped and transmitted to the terminal.

FIG. 10 illustrates a process of receiving control channel resource allocation according to the first and second embodiments of the present invention.

The present invention is a reception operation of a terminal that operates in the same manner in the first and second embodiments, which means that the present invention can be applied to the terminal without additional operations or devices. In step 1001, the terminal receiving the control channel reads the PCFICH and PHICH information at a predetermined position in step 1002. In step 1003, all mini-CCEs are deinterleaved using an interleaver of the same size used for all transmissions. In step 1004, the PCFICH and the PHICH are excluded from the output of the reverse interleaver. In step 1005, the fixed position control channel is removed and the remaining mini-CCEs are read n by n to receive the PDCCH.

11 illustrates a structure of a base station transmitter to which the invention is applied according to an embodiment of the present invention.

The controller 1112 determines a mapping rule for each control channel based on cell information, the number of PHICHs, and the like, and the multiplexer 1113 performs resource mapping of the control channel and RS accordingly. The interleaver preprocessor 1109 receives the PHICH modulation signal and the PCFICH signal 1102 from the PHICH signal generator 1103 and performs preprocessing as in the embodiment. The signal processed by the interleaver preprocessor 1109 is transferred from the PDCCH signal generator 1108 to the interleaver 1110 along with the PDCCH modulated signal. The PDCCH signal generator 1108 is composed of PDCCH signal generators 1117 and 1118 for generating PDCCH signals transmitted to different terminals. The number of CCEs occupied by one PDCCH is determined by the controller 1112. The operation of the interleaver preprocessor 1109 and the interleaver 1110 is determined by the controller 1112 using the interleaver controller 1111, the PHICH signal generator 1103 receives four PHICH signals from the individual PHICH signal generator 115. Gather to create CDM 1106. Reference numeral 1104 and reference numeral 1107 denote signal generators for generating eight PHICH signals, such as PHICH 0-7 and PHICH 8-15, respectively.

The interleaved signal is multiplexed with the RS 1113 in the RS generator 1101, and the signal mapped with the control channel and the RS is multiplexed on the time axis with the signal 1114 with the PDSCH and RS multiplexed on the time axis. Transmitted via 1116.

12 is a diagram illustrating a structure of a terminal receiver to which the invention is applied according to an embodiment of the present invention.

The received signal is converted into a baseband signal via the reception processing device 1201, demultiplexed 1202 on the time axis, and separated into an RS of the PDSCH signal and the PDSCH region, and an RS of the control channel signal and the control channel region. The control channel signal and the RS signal of the control channel region separate the RS, PCFICH, and PHICH in the demultiplexer 1203. The separated RSs 1204 are first passed to the channel estimator 1210 to be used to estimate the channel, and the channel estimates are forwarded to the PCFICH receiver 1205, the PHICH receiver 1206, and the PDCCH receiver 1212, respectively, to the PDSCH signal and the like. It is used to receive a PCFICH signal, a PHICH signal, and a PDCCH signal. When the demultiplexed PCFICH and PHICH channels are reconstructed using the estimated channel, the controller 1209 instructs the interleaver controller 1208 using this information to perform the deinterleaver 1207 and then the PDCCH demapper 1211. After extracting the signal using the PDCCH receiver 1212 to receive.

The PDSCH demapper 1214 extracts the PDSCH signal and delivers the PDSCH signal to the PDSCH receiver 1213. The PDSCH receiver 1213 uses the allocation information of the data channel restored through the PDCCH receiver 1212 to determine the controller 1209. Restore the data channel under control.

1 is a diagram illustrating a subframe structure of an LTE system to which the present invention is applied

2 is a diagram illustrating a control channel structure and an index of a mini-CCE to which the present invention is applied.

3 is a diagram illustrating an example of indexing of mini-CCEs of a control channel to which the present invention is applied.

4 illustrates an interleaver method of a control channel to which the present invention is applied.

5 shows an example of the result of an interleaver to which the present invention is applied.

6 illustrates an interleaver method according to a first embodiment of the present invention.

7 is a flowchart illustrating the operation of a base station according to the first embodiment of the present invention.

8 illustrates an interleaver method according to a second embodiment of the present invention.

9 is a flowchart illustrating the operation of a base station according to a second embodiment of the present invention.

10 is a flowchart illustrating a terminal operation according to an embodiment of the present invention.

11 is a block diagram showing the structure of a base station apparatus according to an embodiment of the present invention;

12 is a block diagram illustrating a structure of a terminal device according to an embodiment of the present invention.

Claims (2)

In a method for transmitting control information in a communication system using an orthogonal frequency division multiple access method, Interleaving the mini-CCE indexes in units of all mini-CCEs, Among the interleaved mini-CCE indexes, a fixed position control channel is allocated to a mini-CCE index which is preset so that a fixed position control channel is allocated to a specific mini-CCE, and a non-fixed control channel is sequentially assigned to the remaining mini-CCE indexes. Process, And mapping the fixed position control channel and the non-fixed control channel to the allocated mini-CCE and transmitting the same. A method of transmitting control information in a communication system using an orthogonal frequency division multiple access scheme, Performing pre-interleaving on the fixed position control channel such that a fixed position control channel is allocated to a specific mini-CCE among all the mini-CCEs in consideration of interleaving performed in all mini-CCE units; Interleaving the pre-interleaved fixed position control channel and the non-fixed position control channel in total mini-CCE units; Allocating the interleaved control channels to a corresponding mini-CCE; And mapping the fixed position control channel and the non-fixed control channel to the allocated mini-CCE and transmitting the same.

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