JP5511005B2 - Receiving apparatus, receiving method, and program - Google Patents

Description

  The present invention relates to a receiving device, a receiving method, and a program.

  In LTE (Long Term Evolution), which is a communication system standard, OFDMA (Orthogonal Frequency Division Multiplexing Access) is adopted as a Downlink radio communication system.

  FIG. 10 is a block diagram showing a schematic configuration of a conventional communication system.

  First, the transmission side will be described.

  On the transmission side, error correction coding, error detection coding, and size adjustment are performed in the coding unit 101 for each user data. Subsequently, in the modulation unit 102, the encoding unit output data supplied from the encoding unit 101 is allocated to each point on the IQ plane according to various modulation schemes, and precoding such as spatial multiplexing and transmission diversity is performed in a timely manner. And data for each transmission antenna is generated.

  Subsequently, in the mapping unit 103, the modulation unit output data supplied from the modulation unit 102 is mapped to each RE (Resource Element) on the frequency axis for each transmission antenna. After mapping for one OFDM symbol, the IFFT (Inverse Fast Fourier Transform) unit 104 converts the output from the mapping unit 103 into data on the time axis for each transmission antenna, and the carrier wave modulation unit 105 receives the IFFT unit 104 from the IFFT unit 104. Are modulated by carrier waves for each transmission antenna and transmitted as transmission data from each transmission antenna (not shown).

  Here, the mapping unit on the frequency axis is referred to as RE, and the unit time for applying IFFT is referred to as OFDM symbol.

  Next, the receiving side will be described.

  On the receiving side, the carrier demodulation unit 106 extracts data on the time axis from the received data. Data on the time axis is converted into data on the frequency axis in an FFT (Fast Fourier Transform) unit 107, and data mapped to each RE is extracted in the demapping unit 108. The extracted data is demodulated in the demodulation unit 109 according to each modulation method, and finally, the decoding unit 110 performs error correction and error detection.

In LTE, a maximum of four OFDM symbols from the OFDM symbol arranged at the head of one sub-frame is used to display a PCFICH (Physical Control Format Channel Channel), PHICH (Physical HANR Indicator Channel) and PHICH (Physical HARQ Indicator Channel). Channel) is transmitted.
PCFICH is data for notifying the receiving terminal of the number of OFDM symbols to which PDCCH is transmitted. The PHICH is data for notifying the receiving terminal of a HARQ (Hybrid Automatic Repeat Request) Indicator. The PDCCH is data for notifying the receiving terminal of various parameters for receiving PDSCH (Physical Downlink Shared Channel), TPC (Transmit Power Control), and the like.

  Here, Non-Patent Document 1 defines a mapping method for PCFICH, PHICH, and PDCCH.

  As defined in Non-Patent Document 1, PCFICH, PHICH, and PDCCH are mapped in units of REG (Resource Element Group).

  FIG. 11 is a diagram illustrating an outline of mapping of PCFICH, PHICH, and PDCCH. In FIG. 11, hatched squares indicate REs in which RSs (Reference Signals) of the respective transmission antennas are arranged. Here, RS is a pilot signal.

  One REG is composed of 6 REs in the OFDM symbol with RS as shown by A in FIG. 11, and 4 REs in the OFDM symbol without RS as shown in B in FIG. 11. Composed. As shown in FIG. 11, the RS mapping position is 6 RE periods for each transmission antenna. The mapping offset position is determined by the cell ID of the base station. Note that RS is excluded from the mapping in the REG.

  According to Section 6.8.5 of Non-Patent Document 1, the mapping information of PHICH and PCFICH is required for PDCCH mapping. The outline is shown in FIG. PDCCH is mapped for each OFDM symbol in the time direction at a position excluding PCFICH and PHICH with REG as a unit. Further, this mapping is performed in the high frequency direction sequentially from the low frequency side. In addition, the numerical value described in each REG in FIG. 12 is a PDCCH symbol-quadruplet number.

  The PDCCH mapping flow defined in Section 6.8.5 of Non-Patent Document 1 is shown in the flowchart of FIG.

  In step S101, the PDCCH symbol-quadruplet number m ″ is initialized to 0, and the RE number k ′ is initialized to 0.

  In step S102, the OFDM symbol number l 'is initialized to 0. In step S103, it is determined whether or not the array (k ′, l ′) having the RE number k ′ and the OFDM symbol number 1 ′ as elements is equal to the REG index pair. The k ′ of the REG index pair is a multiple of 6 when there is an RS, and is a multiple of 4 when there is no RS.

  If it is determined in step S103 that the array (k ′, l ′) is equal to the REG index pair, the procedure proceeds to step S104, and whether or not PCFICH is mapped to REG (k ′, l ′). Is determined.

  If it is determined in step S104 that PCFICH is not mapped to REG (k ′, l ′), the procedure proceeds to step S105, and whether PHICH is mapped to REG (k ′, l ′). Is determined.

  If it is determined in step S105 that PHICH is not mapped to REG (k ′, l ′), the procedure proceeds to step S106, and PDCCH symbol-quadruplet is mapped to REG (k ′, l ′). The In step S107, the PDCCH symbol-quadruplet number m ″ is incremented by 1, and the procedure proceeds to step S108.

  If it is determined in step S103 that the array (k ′, l ′) is not equal to the REG index pair, it is determined in step S104 that PCFICH is mapped to REG (k ′, l ′). If, and in step S105, it is determined that PHICH is mapped to REG (k ′, l ′), the procedure proceeds to step S108.

  In step S108, the OFDM symbol number l 'is incremented by one.

  In step S109, it is determined whether or not the OFDM symbol number l 'is less than the number L, that is, whether or not the maximum OFDM symbol (number L) to which the PDCCH is mapped has been reached.

  If it is determined in step S109 that the OFDM symbol number l ′ is less than the number L, the procedure returns to step S103 because the maximum OFDM symbol (number L) to which the PDCCH is mapped has not been reached. The process is repeated.

  If it is determined in step S109 that the OFDM symbol number l ′ is not less than the number L, since the maximum OFDM symbol (number L) to which the PDCCH is mapped has been reached, the procedure proceeds to step S110, and the RE number k ′. Is incremented by one.

  In step S111, it is determined whether or not the RE number k ′ has reached the maximum RE to which the PDCCH is mapped, and it is determined that the RE number k ′ has not reached the maximum RE to which the PDCCH is mapped. If so, the procedure returns to step S102 and the above-described processing is repeated.

  If it is determined in step S111 that the RE number k ′ has reached the maximum RE to which the PDCCH is mapped, the PDCCH mapping process ends.

  In this way, the PDCCH is mapped using the RE number as a reference.

3GPP TS 36.211, “Physical Channels and Modulation”

  According to the procedure shown in the flowchart of FIG. 12, PDCCH mapping in LTE is performed for each OFDM symbol in the time direction from the low frequency side, and this is sequentially advanced in the frequency direction. The PDCCH mapping needs to be performed while avoiding the REG to which the PCFICH and PHICH are mapped.

  Here, if the mapping procedure shown in the flowchart of FIG. 12 is simply followed in the reverse order to achieve demapping, the PDCCH cannot be demapped unless all OFDM symbols in the time direction are received, and the processing time Overhead increases. Further, a memory for storing RRE (Raw RE) data is also required for a maximum of four OFDM symbols, which increases the circuit scale.

  Therefore, an object of the present invention is to solve the above-described problems, that is, to provide a receiving apparatus, a receiving method, and a program that can reduce the overhead of processing time and can demap PDCCH with a small circuit scale or memory.

  According to the first aspect of the present invention, in accordance with LTE, a PDCCH mapped to OFDM symbol is demapped in a receiving apparatus that receives a signal mapped in units of RE on the frequency axis for each transmission antenna. This PDCCH demapping unit has a PDCCH demapping unit for a REG that is a group of REs and assigned a serial number, and in order of the serial number, the attention REG that is the REG that is noted at that time, PCFICH or Determination means for determining whether or not any PHICH is mapped and the serial number assigned to the target REG corresponds to the current OFDM symbol number input every time one OFDM symbol is received And PCFICH and PHICH are both in the attention REG And PDCCH demapping executing means for demapping the PDCCH of the REG being noticed when the serial number assigned to the noticed REG corresponds to the current OFDM symbol number. A receiving device is provided.

  The PDCCH demapping unit is activated every time one OFDM symbol is received, and the current OFDM symbol number is given as one of parameters when the PDCCH demapping unit is activated.

  According to the second aspect of the present invention, in a reception method for receiving a signal mapped in units of REs on the frequency axis for each transmission antenna in accordance with LTE, a serial number is assigned to a group of REs. A first determination step for determining whether or not at least one of PCFICH and PHICH is mapped to the attention REG which is the REG that is noticed at that time in the order of serial numbers with respect to the REG, and the attention REG Both the PCFICH and PHICH are mapped to the second determination step for determining whether the serial number corresponds to the current OFDM symbol number input every time one OFDM symbol is received, and the REG of interest. And the serial number assigned to the target REG is the current OFDM symbol When corresponding to the number, reception method characterized by performing the PDCCH demapping step demaps the PDCCH of interest REG is provided.

  According to the third aspect of the present invention, in accordance with LTE, a computer of a receiving apparatus that receives a signal mapped in units of REs on the frequency axis for each transmission antenna is assigned a serial number that is a group of REs. A first determination step for determining whether or not at least one of PCFICH and PHICH is mapped to a noticed REG which is a noticed REG at that time in the order of serial numbers, and a noticed REG A second determination step for determining whether the assigned serial number corresponds to the current OFDM symbol number input every time one OFDM symbol is received, and PCFICH and PHICH are both used for the target REG. The serial number assigned to the target REG that is not mapped is the current OFDM s When corresponding to mbol number, and to perform the run and the PDCCH demapping step demaps the PDCCH of interest REG is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the overhead of processing time is small and the receiving apparatus and receiving method which can demap PDCCH with a small circuit scale or memory, and a program can be provided.

It is a block diagram which shows the example of a structure of the demapping circuit provided in a receiver. It is a figure which shows REG arrangement | positioning. It is a figure which shows REG arrangement | positioning. It is a flowchart explaining the process of demapping of PDCCH. It is a figure which shows the mapping image of PCFICH. It is a figure which shows the mapping image of PHICH. It is a figure which shows the mapping image of PHICH. It is a figure explaining the demapping operation | movement using the present OFDM symbol number l' _now . It is a block diagram which shows the structural example of the hardware of a computer. It is a block diagram which shows the schematic structure of the conventional communication system. It is a figure which shows the outline of mapping of PCFICH, PHICH, and PDCCH. It is a figure which shows the mapping information of PHICH and PCFICH required for mapping of PDCCH. It is a flowchart explaining the mapping flow of the conventional PDCCH.

  Hereinafter, a receiving apparatus according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a block diagram illustrating an example of a configuration of a demapping circuit provided in a receiving device such as a mobile phone. The demapping circuit includes a PCFICH demapping unit 11, a PHICH demapping unit 12, and a PDCCH demapping unit 13. The PCFICH demapping unit 11 outputs the REG number of the REG to which the PCFICH is mapped. The PHICH demapping unit 12 outputs the REG number of the REG to which the PHICH symbol-quadruplet is mapped. The PDCCH demapping unit 13 outputs the REG number of the REG to which the PDCCH is mapped.

  The PCFICH demapping unit 11 and the PHICH demapping unit 12 output parameters for PDCCH demapping to the PDCCH demapping unit 13.

The PDCCH demapping unit 13 includes a memory 21, an internal parameter storage unit 22, a REG counter 23, a comparator 24, a counter 25, a REG pair unit 26, and a control unit 27. The PDCCH demapping unit 13 is activated every time one OFDM symbol is received, and a current OFDM symbol number l ′ _now is given as one of parameters at the time of activation.

  The memory 21 stores various parameters output from the PCFICH demapping unit 11 and the PHICH demapping unit 12.

ＰＨＩＣＨ ｓｙｍｂｏｌ−ｑｕａｄｒｕｐｌｅｔ番号

およびＰＨＩＣＨ ｍａｐｐｉｎｇ ｕｎｉｔ番号

を記憶する。ＰＣＦＩＣＨ ｓｙｍｂｏｌ−ｑｕａｄｒｕｐｌｅｔ番号［数１］、ＰＨＩＣＨ ｓｙｍｂｏｌ−ｑｕａｄｒｕｐｌｅｔ番号［数２］、およびＰＨＩＣＨ ｍａｐｐｉｎｇ ｕｎｉｔ番号［数３］の詳細は後述する。 Also, the internal parameter storage unit 22 is a PCFICH symbol-quadruplet number.

PHICH symbol-quadruplet number

And PHICH mapping unit number

Remember. The details of the PCFICH symbol-quadruplet number [Equation 1], the PHICH symbol-quadruplet number [Equation 2], and the PHICH mapping unit number [Equation 3] will be described later.

The REG counter 23 counts the REG of each CH. The comparator 24 determines REG. That is, the comparator 24 maps neither the PCFICH nor the PHICH to the attention REG which is the REG noted at that time in the order of the serial number l ′ with respect to the REG with the serial number l ′. In addition, it is determined whether or not the serial number l ′ assigned to the target REG corresponds to the current OFDM symbol number l ′ _now that is input every time one OFDM symbol is received. The counter 25 counts the PDCCH number and the OFDM symbol number l ′. The REG pair unit 26, when neither PCFICH nor PHICH is mapped to the target REG, and the serial number l ′ assigned to the target REG corresponds to the current OFDM symbol number, is the PDCCH of the target REG Demap. The control unit 27 controls the entire PDCCH demapping unit 13.

  The PCFICH demapping unit 11 performs PCFICH demapping. At this time, the PCFICH demapping unit 11 searches and outputs a PCFICH symbol-quadruplet number [Equation 1] corresponding to the smallest REG number to which the PCFICH is mapped for PDCCH demapping. The PCFICH symbol-quadruplet number [Equation 1] is stored in the memory 21 in the PDCCH demapping unit 13.

  The PHICH demapping unit 12 performs PHICH demapping. Further, at this time, the PHICH demapping unit 12 performs the PHICH symbol-quadruplet number [Equation 2] and the PHICH mapping unit number [Equation 3] corresponding to the smallest REG number to which the PHICH is mapped for PDCCH demapping. Is searched and output. The PHICH symbol-quadruplet number [Equation 2] and the PHICH mapping unit number [Equation 3] are stored in the memory 21 in the PDCCH demapping unit 13.

ＰＨＩＣＨ ｓｙｍｂｏｌ−ｑｕａｄｒｕｐｌｅｔ番号

およびＰＨＩＣＨ ｍａｐｐｉｎｇ ｕｎｉｔ番号

を、それぞれ、ＰＣＦＩＣＨ ｓｙｍｂｏｌ−ｑｕａｄｒｕｐｌｅｔ番号［数１］、ＰＨＩＣＨ ｓｙｍｂｏｌ−ｑｕａｄｒｕｐｌｅｔ番号［数２］、およびＰＨＩＣＨ ｍａｐｐｉｎｇ ｕｎｉｔ番号［数３］に初期化する。また、内部パラメータ記憶部２２は、図４のフローチャートを参照して説明するＰＣＦＩＣＨ関連の更新の手続き（ステップＳ２４）およびＰＨＩＣＨ関連の更新の手続き（ステップＳ２６）において、各パラメータを更新する。 The internal parameter storage unit 22 uses the PCFICH symbol-quadruplet number as a parameter in the initialization procedure (step S13) described with reference to the flowchart of FIG.

PHICH symbol-quadruplet number

And PHICH mapping unit number

Are initialized to a PCFICH symbol-quadruplet number [Equation 1], a PHICH symbol-quadruplet number [Equation 2], and a PHICH mapping unit number [Equation 3], respectively. The internal parameter storage unit 22 updates each parameter in the PCFICH-related update procedure (step S24) and the PHICH-related update procedure (step S26) described with reference to the flowchart of FIG.

  The REG counter 23 counts REG numbers for PCFICH, PHICH, and PDCCH. The REG counter 23 is initialized with the internal parameters after the initialization in the initialization procedure (step S13) described with reference to the flowchart of FIG.

  The REG counter 23 is controlled by the control unit 27 to update the PCFICH related update in the PCFICH related update procedure (step S24) and the PHICH related update procedure (step S26) described with reference to the flowchart of FIG. And PHICH related updates. A REG counter 23 that counts the REG number for PDCCH is provided for the OFDM symbol, and is controlled by the control unit 27 to increment the REG number by 1 in a timely manner.

  That is, the REG counter 23 counts REG numbers for each of PCFICH, PHICH, and PDCCH, and each count value of the REG counter 23 indicates each REG number.

  The comparator 24 receives the REG count value for PDCCH from the REG counter 23, and determines whether or not the REG indicated by the REG number is a PDCCH REG. This determination is performed in the procedure of step S22 described with reference to the flowchart of FIG. If it is determined that it is REG, the comparator 24 subsequently receives the REG count value for PCFICH from the REG counter 23, and whether the REG count value for PCFICH is the same as the REG count value for PDCCH. The result is returned to the control unit 27.

  Next, the comparator 24 receives the REG count value for PHICH from the REG counter 23, and similarly determines whether the REG count value for PHICH is the same as the REG count value for PDCCH, and the result is It returns to the control unit 27. If the REG count value for PDCCH is not equal to the REG count value for PCFICH and not equal to the REG count value for PHICH, the REG indicated by the REG count value for PDCCH is the REG to which the PDCCH is mapped. Therefore, the fact is output to the REG pair unit 26.

  The counter 25 counts the PDCCH symbol-quadruplet number m ″ and the OFDM symbol number l ′, and initializes the PDCCH symbol-quadruplet number m ″ and the OFDM symbol number l ′ in accordance with the control of the control unit 27 as appropriate. Or increment by one.

The OFDM symbol number l ′ by the counter 25 is compared with the current OFDM symbol number l ′ _now in the comparator 24. When these values match, the comparator 24 outputs the fact to the REG pair unit 26. The current OFDM symbol number l ′ _now is input to the PDCCH demapping unit 13 every time one OFDM symbol is received, and is supplied to the comparator 24 via the control unit 27.

  The control unit 27 controls the internal parameter storage unit 22, the REG counter 23, the comparator 24, and the counter 25 according to the procedure described with reference to the flowchart of FIG.

  Other parameters are input from the outside.

  Here, if the mapping procedure shown in the flowchart of FIG. 13 is simply followed in the reverse order to realize the demapping, the demapping is performed based on the RE number (k ′ in FIG. 13). In this case, all the RE numbers at the head of the REGs to which PCFICH and PHICH are mapped must be held in the memory. This leads to an increase in circuit scale. Therefore, in the present embodiment, the REG number of the serial number attached to the REG is used instead of the RE number for PDCCH demapping.

  The arrangement of the REG is common to each 1 RB (Resource Block). Therefore, demapping of PDCCH is performed in units of 1 RB. 2 and 3 are diagrams showing all possible REG arrangements. FIG. 2 is a diagram illustrating a REG arrangement when the number of transmission antennas is 1 or 2. FIG. 3 is a diagram illustrating a REG arrangement when the number of transmission antennas is four. Each square in FIGS. 2 and 3 represents one REG. 2 and 3, the horizontal direction indicates the time direction, and the vertical direction indicates the frequency direction.

  REGs within 1 RB are arranged in three parts, an upper stage, a middle stage, and a lower stage in OFDM symbol without RS. Therefore, the 1-RB demapping process is based on three stages. 2 and FIG. 3, the numerical value in each REG cell (square) indicates the PDCCH symbol-quadruplet number in one RB. Here, for simplicity, FIG. 2 and FIG. 3 do not consider PCFICH or PHICH. However, since PDCCH actually needs to be mapped avoiding REG to which PCFICH or PHICH is mapped, PDCCH The symbol-quadruplet number may not be the numerical value shown in FIG. 2 and FIG.

  Next, PDCCH demapping processing will be described with reference to the flowchart of FIG. In step S11, the PCFICH demapping unit 11 demappings the PCFICH. PCFICH is mapped to OFDM symbol # 0. FIG. 5 is a diagram illustrating a mapping image of PCFICH. Each square in FIG. 5 represents one REG, and each hatched square represents a REG to which PCFICH is demapped. In FIG. 5, the numbers attached to the squares indicate PCFICH symbol-quadruplet numbers.

は、システム帯域幅により６，１５，２５，５０，７５，１００の６通りとなる。１つのＲＢ分のＳＣ（Ｓｕｂ−ｃａｒｒｉｅｒ）数

は、定数であり、１２となる。また、

は、床関数である。

・・・式（１） Here, according to Non-Patent Document 1, an algorithm for calculating a PCFICH mapping pattern is represented by Expression (1). k is a mapping pattern. Number of RBs for one OFDM symbol

Are 6, 15, 25, 50, 75, 100 depending on the system bandwidth. Number of SC (Sub-carrier) for one RB

Is a constant and is 12. Also,

Is a floor function.

... Formula (1)

の剰余とする。また、

は、式（２）で計算される。

・・・式（２）

は、基地局毎に振られた番号（Ｐｈｙｓｉｃａｌ−ｌａｙｅｒ ｃｅｌｌ ｉｄｅｎｔｉｔｙ）であり、０〜５０３の値域をとる。 However, in Formula (1), k is

The remainder. Also,

Is calculated by equation (2).

... Formula (2)

Is a number assigned to each base station (Physical-layer cell identity) and takes a value range of 0 to 503.

つまり６の倍数であることが分かる。ＰＣＦＩＣＨがマッピングされるＯＦＤＭ ｓｙｍｂｏｌ＃０はＲＳ有りのため、ＲＥＧサイズも同様に６となる。したがって、ＰＣＦＩＣＨがマッピングされるＲＥＧ番号は、式（３）により算出できる。ここで、

は［数１２］を［数１５］で除算することにより計算される。

・・・式（３） Looking at the above formula, [Equation 12] is

That is, it is understood that it is a multiple of 6. Since OFDM symbol # 0 to which PCFICH is mapped has an RS, the REG size is 6 as well. Therefore, the REG number to which the PCFICH is mapped can be calculated by Expression (3). here,

Is calculated by dividing [Equation 12] by [Equation 15].

... Formula (3)

の剰余とする。また、

についても同様に、［数１８］の剰余とする。これは、たとえば、式（３）の右辺第２項の加算結果が［数１８］以上になる場合に、加算結果から［数１８］を減算するなどで求められる。ＰＤＣＣＨのデマッピングのために、［数１９］が最小となるＰＣＦＩＣＨ ｓｙｍｂｏｌ−ｑｕａｄｒｕｐｌｅｔ番号を求めて［数１］とする。ここで、ｉはＰＣＦＩＣＨ ｓｙｍｂｏｌ−ｑｕａｄｒｕｐｌｅｔ番号として、０〜３の値をとる。 However, [Equation 16] is

The remainder. Also,

Similarly, the remainder of [Equation 18] is used. This can be obtained, for example, by subtracting [Equation 18] from the addition result when the addition result of the second term on the right side of Equation (3) is equal to or greater than [Equation 18]. For the PDCCH demapping, a PCFICH symbol-quadruplet number that minimizes [Equation 19] is obtained and is set as [Equation 1]. Here, i takes a value of 0 to 3 as a PCFICH symbol-quadruplet number.

  Next, in step S12, the PHICH demapping unit 12 demaps the PHICH.

  PHICH is normally mapped to OFDM symbol # 0, but in the case of Extended PHICH duration, it is mapped to a plurality of OFDM symbols.

  FIG. 6 is a diagram illustrating a normal PHICH mapping image. FIG. 7 is a diagram illustrating a mapping image of PHICH in the case of Extended PHICH duration. The right side of FIG. 7 shows a mapping image of PHICH in the case of Extended PHICH duration and MBSFN subframe. In the case of Extended PHICH duration and MBSFN subframe, mapping is performed alternately every 2REG on 2OFDM symbol, but in FIG. 7, it is expressed as being alternately mapped per 1REG.

  Each of the squares in FIGS. 6 and 7 represents one REG, and the hatched square represents a REG to which PHICH is mapped. In FIG. 6 and FIG. 7, the numbers attached to the squares indicate PHICH symbol-quadruplet numbers.

・・・式（４）
ＰＨＩＣＨ ｓｙｍｂｏｌ−ｑｕａｄｒｕｐｌｅｔ番号ｉは、０〜２の値をとる。ＰＨＩＣＨ ｍａｐｐｉｎｇ ｕｎｉｔ番号ｍ’は、Ｎｏｒｍａｌ ＣＰ時において、ＰＨＩＣＨ ｇｒｏｕｐ番号（０〜２５）、ＥｘｔｅｎｄｅｄＣＰ時において、ＰＨＩＣＨ ｇｒｏｕｐ番号（０〜５０）を２で割って小数点以下を切り捨てた値をとる。 Here, according to Non-Patent Document 1, an algorithm for calculating a PHICH mapping pattern is as follows. First, the OFDM symbol number li ′ to which the PHICH is mapped is determined by Expression (4).

... Formula (4)
The PHICH symbol-quadruplet number i takes a value of 0-2. The PHICH mapping unit number m ′ is a value obtained by dividing the PHICH group number (0 to 25) at the time of Normal CP and by dividing the PHICH group number (0 to 50) by 2 at the time of Extended CP.

  PHICH is mapped to 2OFDM symbol in the case of Extended PHICH duration and MBSFN subframe, and to 3OFDM symbol in the case of simply Extended PHICH duration. In the case of Normal PHICH duration, PHICH is mapped to OFDM symbol # 0.

  Subsequently, the REG number to which the PHICH in each OFDM symbol is mapped is determined as follows.

・・・式（５） In the case of Extended PHICH duration and MBSFN subframe, the REG number to which the PHICH is mapped is determined by Equation (5).

... Formula (5)

・・・式（６） In other cases, the REG number to which the PHICH is mapped is determined by Equation (6).

... Formula (6)

で表される。ＯＦＤＭ ｓｙｍｂｏｌ番号ｌ_ｉ’のＲＥＧ数

は、ＯＦＤＭ ｓｙｍｂｏｌ＃０の場合、ＰＣＦＩＣＨがマッピングされたＲＥＧを除いたＲＥＧ数となる。 Here, the REG number to which the i-th PHICH symbol-quadruplet is mapped is

It is represented by REG number of OFDM symbol number l _i '

Is the number of REGs excluding the REG to which PCFICH is mapped in the case of OFDM symbol # 0.

  At the time of PHICH demapping, the PHICH symbol-quadruplet number i and the PHICH mapping unit number m ′ where [Equation 23] is minimized are searched and stored in [Equation 2] and [Equation 3], respectively. Here, in the case of Extended PHICH duration, the PHICH is mapped to a plurality of OFDM symbols. In this case, it is held in the memory 21 for each OFDM symbol.

  In step S13, the internal parameter storage unit 22, the REG counter 23, and the counter 25 indicate the PDCCH symbol-quadruplet number and REG number, the minimum REG number to which PCFICH is mapped, and the minimum REG number to which PHICH is mapped. Initialize each.

  That is, the REG counter 23 initializes the PDCCH symbol quadruplet number by setting m ″ to 0.

・・・式（７） In addition, the internal parameter storage unit 22 initializes the PCFICH symbol quadruplet number as shown in Expression (7).

... Formula (7)

・・・式（８） Further, the REG counter 23 initializes the PCFICH REG number as shown in Expression (8).

... Formula (8)

・・・式（９） Furthermore, the variable i is incremented by 1 from 0, and while the variable i is less than the number of OFDM symbols L to which the PDCCH is mapped, the internal parameter storage unit 22 performs the following operation using the equations (9) and (10): A PHICH symbol quadruplet number, a PHICH mapping unit number, and a PHICH REG number are initialized.

... Formula (9)

  Note that the variable i is incremented from 0 to less than the OFDM symbol number L to which the PDCCH is mapped, but the initialization by the expression (9) of the PHICH symbol quadruplet number, the PHICH mapping unit number, and the PHICH REG number is This is performed when i is less than the number L ′ of OFDM symbols to which PHICH is mapped.

・・・式（１０） When the variable i is incremented by 1 and becomes less than the number of OFDM symbols L to which the PDCCH is mapped, or when the variable i is less than the number of OFDM symbols L to which the PHICH is mapped, As shown in (10), the internal parameter storage unit 22 is initialized with a large value that does not actually exist in the OFDM symbol to which PHICH is not mapped.

... Formula (10)

には実在しない大きな値として３０１などを代入してもよいが、そもそもＰＣＦＩＣＨの判定をｌ’＝０のときにのみ行なうようにしてもよい。 In addition,

For example, 301 may be substituted as a large value that does not exist, but PCFICH determination may be performed only when l ′ = 0.

  Here, a REG included in one RB will be described.

  The number of REGs included in one RB is determined by whether or not an RS is mapped to the OFDM symbol, and is 2 when there is an RS and 3 when there is no RS. Here, in order to simplify the processing, it is assumed that the number of REGs included in one RB is all three.

  Hereinafter, the REG having a low frequency is referred to as a lower stage, a middle stage, and an upper stage. The presence or absence of RS depends on the OFDM symbol, the number of TxAnts, and the CP length. When the number of REGs is 2, it means that there is no middle stage, and it is determined that it is not “REG” in the subsequent process, and the procedure from step S23 to step S30 is skipped.

  Note that only when the extended CP is narrow band (the number of RBs is 10 or less) and the CFI is 3, the number of REGs of OFDM symbol # 3 is 2, and there is no middle stage. At this time, it is necessary to map the PDCCH to the upper REG of the OFDM symbol # 3 before the upper REG of the OFDM symbol # 1 and # 2 in the case of the OFDM symbol # 2 when the number of TxAnts is four. Because there is, it needs attention.

  In step S14 and step S15, the procedures of steps S21 to S32 described below are repeated for the lower stage, the middle stage, and the upper stage in one RB.

  In step S21, the counter 25 sets the OFDM symbol number li 'to 0. In step S22, the comparator 24 receives the REG count value for PDCCH from the REG counter 23, determines whether or not it is a PDCCH REG, and if it is determined to be REG, the procedure proceeds to step S23.

  If it is determined in step S22 that it is REG, the procedure proceeds to step S23.

  In step S23, the comparator 24 receives the REG count value for PCFICH from the REG counter 23, and determines whether the REG count value for PCFICH is the same as the REG count value for PDCCH. It is determined whether PCFICH is mapped to REG indicated by the REG count value.

  If it is determined in step S23 that the PCFICH is mapped to the REG indicated by the PDCCH REG count value, the procedure proceeds to step S24, and the PCFICH related update is performed in the REG counter 23.

も

の剰余とする。

・・・式（１１）

・・・式（１２） That is, when the REG to which the PCFICH is mapped is reached, the mapping of the PDCCH to the REG is skipped. At this time, the REG to which the PCFICH is mapped is updated to the next PCFICH symbol-quadruplet number. The PCFICH symbol quadruplet number is updated by the calculation shown in Expression (11), and the PCFICH REG number is updated by the calculation shown in Expression (12). Since the number of PCFICH symbol-quadruplets is 4, the operation is mod 4. Also

Also

The remainder.

... Formula (11)

... Formula (12)

  After step S24, the procedure proceeds to step S30.

  If it is determined in step S23 that the PCFICH is not mapped to the REG indicated by the PDCCH REG count value, the procedure proceeds to step S25. In step S25, the comparator 24 receives the REG count value for PHICH from the REG counter 23, and determines whether the REG count value for PHICH is the same as the REG count value for PDCCH. It is determined whether PHICH is mapped to the REG indicated by the REG count value.

  If it is determined in step S25 that PHICH is mapped to REG indicated by the REG count value for PDCCH, the procedure proceeds to step S26, and PHICH related updating is performed in REG counter 23.

  That is, when the REG to which the PHICH is mapped is reached, the mapping of the PDCCH to the REG is skipped. At this time, the REG to which the PHICH is mapped is updated to the next PHICH symbol-quadruplet number. Since the PHICH symbol-quadruplet number is 3, the operation is mod 3. Here, for simplicity of explanation, the description is made without considering the MBSFN case.

・・・式（１３）

・・・式（１４） More specifically, when the condition represented by Expression (13) is satisfied, the PHICH symbol-quadruplet number is updated by the operation represented by Expression (14).

... Formula (13)

... Formula (14)

がＰＨＩＣＨ ｍａｐｐｉｎｇ ｕｎｉｔ数

に達していたら、ＰＨＩＣＨ ｓｙｍｂｏｌ−ｑｕａｄｒｕｐｌｅｔ番号

が更新されて、式（１５）に示されるように、ＰＨＩＣＨ ｍａｐｐｉｎｇ ｕｎｉｔ番号

が０に初期化される。

・・・式（１５） That is, the PHICH mapping unit number that satisfies the condition expressed by the equation (13)

Is the number of PHICH mapping units

If you have reached PHICH symbol-quadruplet number

Is updated and the PHICH mapping unit number as shown in Equation (15)

Is initialized to 0.

... Formula (15)

が１だけインクリメントされる。

・・・式（１６） When the condition shown in Expression (13) does not hold, as shown in Expression (16), PHICH mapping unit number

Is incremented by one.

... Formula (16)

が更新される。

・・・式（１７） After the update shown in Equation (13) to Equation (16), the REG number to which PHICH is mapped as shown in Equation (17)

Is updated.

... Formula (17)

を参照せずに、

を１だけインクリメントすることで算出できる。なお、ＭＢＳＦＮのケースでは２ＲＥＧ単位にＯＦＤＭ ｓｙｍｂｏｌが代わるため、３だけインクリメントされることになる。また、ＰＨＩＣＨ ｓｙｍｂｏｌ−ｑｕａｄｒｕｐｌｅｔ番号

の更新時にも２ＲＥＧ単位の考慮が必要となる。 Here, when the case of MBSFN is not considered, since PHICH symbol-quadruplet is continuously mapped in units of PHICH mapping unit, updating of REG to which PHICH is mapped is performed.

Without referring to

Can be calculated by incrementing by one. In the case of MBSFN, since OFDM symbol is replaced in units of 2REG, it is incremented by 3. In addition, PHICH symbol-quadruplet number

Even when updating, it is necessary to consider 2REG units.

  After step S26, the procedure proceeds to step S30.

In step S25, it is determined that PHICH is not mapped to the REG indicated by the REG count value for PDCCH. In step S27, the procedure is performed only when the OFDM symbol number l ′ matches the current ODFM symbol number l ′ _now. Proceed to step S28. In step S28, the REG pair unit 26 performs PDCCH demapping. That is, the REG pair unit 26 demaps the REG of the PDCCH symbol-quadruplet number indicated by the REG count value for PDCCH. Here, nRS indicates the number of RSs in the REG and is 0 or 2.

After step S28, or if the OFDM symbol number l ′ does not match the current ODFM symbol number l ′ _{now in} step S27, the procedure proceeds to step S29. In step S29, the internal parameter storage unit 22 increments the PDCCH symbol-quadruplet number m ″ by 1. In step S30, the REG counter 23 increments the REG number for each OFDM symbol by 1.

  In step S31, the REG counter 23 increments the OFDM symbol number l 'by 1. In step S31, the comparator 24 determines whether or not the OFDM symbol number l ′ has reached the number L of OFDM symbols to which the PDCCH is mapped. If it is determined in step S31 that the OFDM symbol number l 'has not reached the number L of OFDM symbols to which the PDCCH is mapped, the procedure returns to step S22 and the above-described processing is repeated.

  In step S14 and step S15, when the processing described above is repeated for the lower stage, the middle stage, and the upper stage in one RB, the procedure proceeds to step S16, and the control unit 27 sets nREG [0] for one OFDM symbol. If it is determined whether or not nREG [0] is equal to twice the number of RBs [Equation 7] for one OFDM symbol, it is determined whether or not the number of RBs [Equation 7] is equal to twice. Returning to S14, the above-described processing is repeated.

  If it is determined in step S16 that nREG [0] is equal to twice the number of RBs for one OFDM symbol [Equation 7], the PDCCH demapping process ends.

  In this way, in the PDCCH demapping, a REG is assigned a number instead of an RE number. When the PDCCH is demapped, the REG numbers to which the PCFICH and PHICH are mapped are calculated while being calculated in ascending order, so that the “RE number at the beginning of the REG to which the PCFICH and PHICH are mapped is changed. It is possible to eliminate the need for a “memory for holding all”. That is, in LTE, PDCCH demapping can be performed in a small circuit.

Also, a parameter called l' _now indicating the current OFDM symbol number is added to the PDCCH demapping, and demapping is executed only when the OFDM symbol number l 'matches the current OFDM symbol number l' _now .

  PDCCH demapping is performed by skipping a REG to which PCFICH or OHICH is mapped. In order to find a REG to which PCFICH or OHICH is mapped, it is necessary to search a series of REGs in order. On the other hand, PDCCH demapping does not need to consider the order of REG. Therefore, a search for all REGs is performed for each OFDM symbol, and PDCCH demapping is performed only for the REGs of the current OFDM symbol.

8, 'a diagram for explaining the de-mapping operation using the _now, the current OFDM symbol number l' current OFDM symbol number l in the case of performing demapping without considering _now, the OFDM symbol number l ' An example of operation timing comparison with the case where demapping is executed only when the current OFDM symbol number l ′ _now matches is shown.

When demapping is executed without considering the current OFDM symbol number l ′ _now , that is, when processing is performed for each series of REGs, the REG search may be performed once. However, the process can be started only after all those REGs have been received. On the other hand, when processing is performed for each OFDM symbol, it is necessary to perform REG search (the processing shown in FIG. 4) each time. However, every time an RRE for one OFDM symbol is received, PDCCH data is received. Since mapping can be performed, processing overhead and memory for storing RRE data can be reduced.

  In the above description, the PCFICH symbol-quadruplet number corresponding to the smallest REG number to which PCFICH is mapped is searched, and in the PDCCH demapping, a method for generating and using the PCFICH demapping pattern sequentially is described. However, in the first place, four PCFICH demapping patterns may be held and used sequentially, or the four patterns may be rearranged and used.

  Further, a PHICH symbol-quadruplet number and a PHICH mapping unit number corresponding to the smallest REG number to which PHICH is mapped are searched, and in PDCCH demapping, first, the PHICH symbol-quadruplet number and the PHICH mapping unitIC are initialized from the initial number. The minimum REG number to which the PHICH is mapped is searched for at the time of PHICH demapping, and may be retained and used for demapping of the PDCCH.

  The series of processes described above can be executed by hardware or can be executed by software. When a series of processing is executed by software, a program constituting the software executes various functions by installing a computer incorporated in dedicated hardware or various programs. For example, it is installed from a program recording medium in a general-purpose personal computer or the like.

  FIG. 9 is a block diagram illustrating a hardware configuration example of a computer that executes the above-described series of processing by a program.

  In the computer, a CPU (Central Processing Unit) 51, a ROM (Read Only Memory) 52, and a RAM (Random Access Memory) 53 are connected to each other by a bus 54.

  An input / output interface 55 is further connected to the bus 54. The input / output interface 55 includes an input unit 56 composed of a keyboard, mouse, microphone, etc., an output unit 57 composed of a display, a speaker, etc., a storage unit 58 composed of a hard disk and a non-volatile memory, and a communication unit 59 composed of a network interface. A drive 60 for driving a removable medium 61 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory is connected.

  In the computer configured as described above, the CPU 51 loads the program stored in the storage unit 58 to the RAM 53 via the input / output interface 55 and the bus 54 and executes the program, for example. Is performed.

  The program executed by the computer (CPU 51) is, for example, a magnetic disk (including a flexible disk), an optical disk (CD-ROM (Compact Disc-Read Only Memory), DVD (Digital Versatile Disc), etc.), a magneto-optical disk, or a semiconductor. It is recorded on a removable medium 61, which is a package medium composed of a memory or the like, or is provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital satellite broadcasting.

  The program can be installed in the computer by installing the removable medium 61 in the drive 60 and storing it in the storage unit 58 via the input / output interface 55. Further, the program can be installed in a computer by being received by the communication unit 59 via a wired or wireless transmission medium and stored in the storage unit 58. In addition, the program can be installed in the computer in advance by storing the program in the ROM 52 or the storage unit 58 in advance.

  The program executed by the computer may be a program that is processed in time series in the order described in this specification, or in parallel or at a necessary timing such as when a call is made. It may be a program for processing.

  The embodiments of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

11 PCFICH demapping unit 12 PHICH demapping unit 13 PDCCH demapping unit 21 Memory 22 Internal parameter storage unit 23 REG counter 24 Comparator 25 Counter 26 REG pair unit 27 Control unit

Claims (4)

In a receiving apparatus that receives a signal mapped in units of RE (Resource Element) on the frequency axis for each transmission antenna in accordance with LTE (Long Term Evolution),
A PDCCH demapping unit for demapping a PDCCH (Physical Downlink Control Channel) mapped to an OFDM (Orthogonal Frequency Division Multiplexing) symbol;
The PDCCH demapping unit is
With respect to a REG (Resource Element Group) that is a group of REs and is assigned a serial number, a PCFICH (Physical Control Indicator Channel) or PHICH is added to the attention REG that is the REG noted at that time in the order of the serial numbers. None of (Physical HARQ (Hybrid Automatic Repeat Request) Indicator Channel) is mapped, and the serial number assigned to the attention REG is the current OFDM input every time one OFDM symbol is received. determining means for determining whether or not the symbol number corresponds;
When neither PCFICH nor PHICH is mapped to the attention REG, and the serial number assigned to the attention REG corresponds to the current OFDM symbol number, the PDCCH of the attention REG is de-mapped. And a PDCCH demapping executing means. The receiving device according to claim 1,
The PDCCH demapping unit is activated every time one OFDM symbol is received,
The present OFDM symbol number is given as one of parameters when the PDCCH demapping unit is activated. In a reception method for receiving a signal mapped in units of RE on the frequency axis for each transmission antenna in accordance with LTE,
For REGs that are groups of REs and are assigned serial numbers, in the order of the serial numbers,
A first determination step of determining whether or not at least one of PCFICH and PHICH is mapped to the attention REG that is the REG that has attracted attention at that time;
A second determination step for determining whether the serial number assigned to the attention REG corresponds to a current OFDM symbol number input every time one OFDM symbol is received;
When neither PCFICH nor PHICH is mapped to the target REG, and the serial number assigned to the target REG corresponds to the current OFDM symbol number, the PDCCH for demapping the PDCCH of the target REG And a demapping step. In accordance with LTE, a computer of a receiving apparatus that receives a signal mapped in units of RE on the frequency axis for each transmission antenna,
For REGs that are groups of REs and are assigned serial numbers, in the order of the serial numbers,
A first determination step of determining whether or not at least one of PCFICH and PHICH is mapped to the attention REG that is the REG that has attracted attention at that time;
A second determination step for determining whether the serial number assigned to the attention REG corresponds to a current OFDM symbol number input every time one OFDM symbol is received;
When neither PCFICH nor PHICH is mapped to the target REG, and the serial number assigned to the target REG corresponds to the current OFDM symbol number, the PDCCH for demapping the PDCCH of the target REG Demapping step and a program that performs processing.

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