JP5906128B2 - Transmission device, reception device, transmission program, reception program - Google Patents

Description

  The present invention relates to a transmission apparatus that transmits data using an OFDM (Orthogonal Frequency Division Multiplexing) signal, a reception apparatus that receives data transmitted from the transmission apparatus, a transmission program, and a reception program. .

  In an OFDM transmission system that transmits data using a plurality of OFDM signals in the same frequency band, generally, a transmission path response is estimated using a pilot signal. As a method of arranging a pilot signal in an OFDM symbol, for example, there is a scattered pilot (SP) system as shown in FIG. In the SP method, pilot signals are distributed and arranged on specific subcarriers and symbols. FIG. 21 exemplifies a case where pilot signals are arranged once every 12 carriers and once every 4 symbols. The pilot signal is allocated to each carrier number (3n-2) (n is a positive integer), and the symbol signal shift amount between adjacent pilot carriers is “1”. ing. The SP system is also employed in a transmission system (ARIB STD-B31) for terrestrial digital television broadcasting.

  In an OFDM transmission system, parameter data such as OFDM signal control information may be transmitted using a carrier symbol at a special position. In the transmission system of digital terrestrial television broadcasting, it is called AC (Auxiliary Channel), TMCC (Transmission Multiplexing Configuration Control), using a carrier symbol at a position determined using a random number table, a synchronization signal, a carrier modulation system, Parameter data such as the coding rate of the error correction code is transmitted.

  As described above, in the OFDM transmission system, it is necessary to determine the arrangement of pilot signals in advance. It is also necessary to determine the position of the carrier symbol for transmitting parameter data such as control information of the OFDM signal.

By the way, for example, Alamouti space-time block coding (STBC) is known as block coding of data transmitted by an OFDM signal. The Alamouti space-time block coding matrix is expressed by the following equation (1). In the formula (1), ^* represents a complex conjugate.

  In Equation (1), the row of the matrix A corresponds to the transmission antenna number. Therefore, the matrix A is used when signals are transmitted with two transmission antennas. The column of the matrix A corresponds to the symbol number (time). When transmitting the space-time block-encoded data based on Equation (1) using a plurality of OFDM signals, the transmission / reception apparatus needs to determine the arrangement of pilot signals.

  For example, when data is transmitted by the SP method shown in FIG. 21, the space-time block coded data is allocated to the position represented as “data” in FIG. Therefore, when signals are transmitted by two transmission antennas, data transmitted from the respective antennas are allocated as shown by antenna 1 and antenna 2 in FIG.

  Here, in the space-time block coding of Equation (1), two OFDM symbols are processed as a set. Therefore, in the case of FIG. 22, the symbol numbers (1, 2) are a pair, and (3, 4), (5, 6),. FIG. 22 shows an example of data assigned to carrier number 2 and symbol number (1, 2).

  However, pilot signals are arranged at positions that are paired with the positions indicated by “x” in FIG. Therefore, space-time block encoded data cannot be assigned to the position indicated by “x”. With respect to this point, a method of arranging a pilot signal at a position indicated by “×” in FIG. 22 is known (see, for example, Patent Document 1). In this method, it is possible to improve the estimation accuracy of the channel response obtained by the receiving device as the pilot signal increases, but the ratio of the pilot signal to the total signal increases, so the data including the parameter data is increased. The transmission capacity will be reduced. Similar problems also occur when transmitting spatial frequency block coded data.

Special table 2008-533801 gazette

  Therefore, an object of the present invention made in view of the above-described viewpoint is to transmit block-encoded data and parameter data without causing a reduction in transmission capacity and a reduction in estimation accuracy of a transmission path response, and a configuration. Is provided, a receiving device that receives data transmitted from the transmitting device, a transmission program, and a receiving program.

  In order to solve the above-described problem, a transmitting apparatus according to the present invention is a transmitting apparatus that transmits data using an OFDM signal, and generates a data block including N (N is a positive integer of 2 or more) pieces of data. Based on an encoding unit, a pilot signal generation unit that generates a pilot signal for channel response estimation, a parameter data generation unit that generates parameter data of an OFDM signal, the data block, the pilot signal, and the parameter data An OFDM symbol composing unit that constitutes an OFDM symbol of the OFDM signal, the OFDM symbol composing unit arranging the pilot signal in a predetermined carrier symbol of the OFDM symbol, and the data block of the OFDM symbol Place on the adjacent data carrier symbol and the rest Arranging the parameter data in over data carrier symbols, characterized in that.

  Furthermore, in the transmission apparatus according to the present invention, the block encoding unit generates the data block that is space-time block encoded, and the OFDM symbol configuration unit uses ( The pilot signal is arranged at a rate of once in (N × M + 1) symbols (M is a positive integer).

Furthermore, in the transmission apparatus according to the present invention, when the block encoding unit has K = (N × M + 1) and m is a positive integer, the number of OFDM symbols Ps constituting the OFDM frame is Ps = mK + (N -1), which constitutes an OFDM symbol.

  Further, in the transmission apparatus according to the present invention, the block encoding unit generates the data block subjected to spatial frequency block encoding, and the OFDM symbol configuration unit applies ( N × M + 1) the pilot signal is arranged at a rate of once per carrier (M is a positive integer).

Furthermore, in the transmission apparatus according to the present invention, the block encoding unit may calculate the number of carriers Pc constituting the OFDM symbol as Pc = mK + (N−, where K = (N × M + 1) and m is a positive integer. 1), which constitutes an OFDM symbol.

  In order to solve the above problem, a receiving apparatus according to the present invention is a receiving apparatus that receives data transmitted from any one of the above-described transmitting apparatuses, and demodulates the received OFDM signal according to the configuration of the OFDM symbol. An OFDM demodulator and a block code decoder for decoding a data block from the demodulated OFDM signal are provided.

  Moreover, in order to solve the said subject, the transmission program which concerns on this invention makes a computer function as one of the said transmission apparatuses.

  Moreover, in order to solve the said subject, the receiving program which concerns on this invention makes a computer function as said receiving apparatus.

  According to the present invention, transmission and reception of block-coded data and parameter data can be performed without causing a decrease in transmission capacity and a decrease in estimation accuracy of a transmission path response. The configuration can be simplified.

It is a figure for demonstrating the outline | summary of the OFDM symbol structure by the transmitter which concerns on 1st Embodiment. In FIG. 1, it is a figure which shows the OFDM symbol structure in the case of Ps = mK. In FIG. 1, it is a figure which shows the OFDM symbol structure in the case of Ps = mK + 1. In FIG. 1, it is a figure which shows the OFDM symbol structure in the case of Ps = mK + 2. In FIG. 1, it is a figure which shows the OFDM symbol structure in the case of Ps = mK + 3. In FIG. 1, it is a figure which shows the OFDM symbol structure in the case of Ps = mK + 4. In 1st Embodiment, it is a block diagram of the OFDM symbol in the case of N = 3, M = 2, and Ps = mK + 2. In 1st Embodiment, it is a block diagram of the OFDM symbol in the case of N = 4, M = 2, Ps = mK + 3, and x = 1. In 1st Embodiment, it is a block diagram of the OFDM symbol in the case of N = 4, M = 2, Ps = mK + 3, and x = 2. It is a flowchart which shows the structure method of the OFDM symbol of 1st Embodiment. It is explanatory drawing of the process by FIG.10 S106. It is explanatory drawing of the process by FIG.10 S106. It is a figure for demonstrating the outline | summary of the OFDM symbol structure by the transmitter which concerns on 2nd Embodiment. In FIG. 13, it is a block diagram of an OFDM symbol when K = 9 and Pc = mK. In FIG. 13, it is a block diagram of an OFDM symbol when K = 9 and Pc = mK + 1. It is a functional block diagram which shows the structure of the principal part of the OFDM modulation part of FIG. It is a functional block diagram which shows the structure of the principal part of the transmitter which concerns on 3rd Embodiment. It is a functional block diagram which shows the structure of the principal part of the OFDM modulation part of FIG. It is a functional block diagram which shows the structure of the principal part of the receiver which concerns on 4th Embodiment. It is a functional block diagram which shows the structure of the principal part of the OFDM demodulation part of FIG. It is a figure which shows arrangement | positioning of the pilot signal in the OFDM symbol of SP system. It is a figure which shows data allocation in the case of transmitting the space-time block coding data with two transmission antennas.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the symbol configuration of the OFDM signal by the transmission apparatus according to the present invention will be described. In the following description, a symbol located at a symbol number or carrier number to which data is assigned is referred to as a data carrier symbol. Further, in the configuration diagram of the OFDM symbol described below, the pilot signal is indicated by hatching, the data is indicated by white, and the data block is indicated by a thick frame.

  In the block encoding, the number of data that forms a set treated as one block is N (N is a positive integer of 2 or more). In the case of N = 2, for example, Alamouti space-time block coding of Equation (1) can be used. In the case of N = 4, for example, space-time block coding by H. Jafarkahni (for example, “A quasi-orthogonal space-time block code”, IEEE Transactions on Communications, vol49, no.1, pp.1-4, Jan 2001, etc.) can be used.

(First embodiment)
First, as a first embodiment, an OFDM symbol configuration when transmitting data block-coded in the time direction by space-time block coding will be described.

  FIG. 1 is a diagram for explaining an outline of an OFDM symbol configuration by the transmission apparatus according to the first embodiment of the present invention. In FIG. 1, space-time block coding is performed with 2 symbols (N = 2), and data is transmitted by the SP method. In the SP method, pilot signals are distributed and arranged on specific carriers and symbols. FIG. 1 illustrates a case where pilot signals are arranged once every 15 carriers and once every (N × M + 1) symbols. However, M is the number of data blocks (positive integer) continuously arranged in the time direction, and FIG. 1 illustrates the case of M = 2. The pilot signal is arranged in each carrier with the carrier number (3n-2), and the symbol signal shift amount x between adjacent pilot carriers is “1”. Hereinafter, K = N × M + 1 (K = 5 in the case of FIG. 1), and K OFDM symbols are referred to as symbol blocks.

  In FIG. 1, data blocks cannot be allocated to data carrier symbols indicated by “x”. Therefore, in the present embodiment, parameter data is transmitted using data carrier symbols indicated by “x”.

  Hereinafter, a specific arrangement example of carrier symbols for transmitting parameter data according to the present embodiment will be described.

2 to 6 are configuration diagrams of OFDM symbols in which N = 2 and M = 2 and the number of OFDM symbols constituting the OFDM frame is Ps. FIG. 2 shows a case where Ps = mK (m is a positive integer). In this case, parameter data is transmitted at (symbol number 1, carrier number 4), (symbol number 1, carrier number 10),. When increasing the ratio of transmitting parameter data, Ps is decreased. Also, data transmitted with carrier numbers 2, 3, 5, 6,. If the data block is assigned to the carrier numbers 2, 3, 5, 6,..., The transmission capacity increases, but parameter data may be assigned.

  3 to 6 are configuration diagrams of OFDM symbols when Ps ≠ mK. FIG. 3 is an example in which Ps = mK + (N−1), that is, Ps = mK + 1. FIG. 4 is an example in which Ps = mK + 2. FIG. 5 is an example in which Ps = mK + 3. FIG. 6 is an example in which Ps = mK + 4.

2 to 6, the position of the symbol number “x” is different, but the position of “x” is the position of the symbol number 1 and the symbol number Ps in FIGS. 2 to 6. That is, it is located at the start symbol and end symbol of the period of the OFDM signal. Therefore, by assigning parameter data to the start symbol and the end symbol of the OFDM signal, it is possible to set the parameter for each OFDM signal cycle. In particular, the case of FIG. 3 has an advantage that the number of data blocks transmitted on each carrier to which a pilot signal is assigned can be made constant in the number of OFDM symbols Ps constituting the OFDM frame .

  FIG. 7 is a configuration diagram of an OFDM symbol when N = 3, M = 2, and Ps = mK + (N−1), that is, Ps = mK + 2. The pilot signal is arranged once every 21 carriers and once every 7 symbols. The pilot signal is arranged in each carrier with the carrier number (3n-2), and the symbol signal shift amount x between adjacent pilot carriers is “1”.

  8 and 9 are configuration diagrams of OFDM symbols when N = 4 and M = 2 and Ps = mK + (N−1), that is, Ps = mK + 3. 8 and 9 exemplify a case where pilot signals are arranged once every 27 carriers and once every 9 symbols. Also, the pilot signal is arranged in each carrier of the carrier number (3n-2), and the symbol signal shift amount x between adjacent pilot carriers is “1” in the case of FIG. In the case of FIG. 9, it is “2”.

7 to 9, each carrier to which a pilot signal is assigned transmits parameter data with data carrier symbols indicated by “x” to which no data block can be assigned. In the case of FIGS. 7 to 9, each carrier to which a pilot signal is assigned has a total sum of the number of symbols transmitting pilot signals and the number of symbols transmitting parameter data in the number of OFDM symbols Ps constituting the OFDM frame. Will be equal. Therefore, similarly to the case of FIG. 3, there is an advantage that the number of transmitted data blocks can be made constant in the number of OFDM symbols Ps constituting the OFDM frame .

  FIG. 10 is a flowchart showing an OFDM symbol configuration method according to the first embodiment. First, the number N of data constituting the data block is determined (step S101). Next, the number M of data blocks to be continuously arranged in the time direction is determined (step S102). Thereafter, the symbol number Z in which the scattered pilot is arranged for a certain carrier is determined at a cycle of K (K = N × M + 1) (step S103).

  Next, the scattered pilot position determined in step S103 is determined as the scattered pilot position every time x (x <K) in the symbol direction and y-shifted in the carrier direction (step S104). Thereafter, M data blocks are arranged in the symbol direction except for the scattered pilot position (step S105). Then, parameter data is arranged on a carrier symbol to which no data block is assigned (step S106).

  Here, the parameter data arrangement processing in step S106 will be described in more detail with reference to FIGS. FIG. 11 is a diagram for explaining a determination formula in each pilot carrier when parameter data is assigned to the first symbol of pilot carrier numbers 1 to (N−1). FIG. 12 is a diagram for explaining a determination formula in each pilot carrier when parameter data is assigned to the symbols of the tail part from the pilot carrier symbol number Ps to (Ps− (N−2)).

  11 and 12, pilot carrier numbers 0, 1, 2,..., I,... Correspond to carrier numbers (3n-2) in which pilot signals are arranged. Further, x indicates the amount of shift in the symbol direction of the scattered pilot between adjacent carriers to which pilot signals are assigned. Therefore, in the case of FIGS. 1-8, x = 1, and in the case of FIG. 9, x = 2.

  In FIG. 11, parameter data is assigned to Bi symbols from the beginning for pilot carrier number i (0, 1, 2,...). Here, Bi is represented by Bi = (i × x)% K% N. That is, Bi is the remainder obtained by dividing (i × x) by K (K = N × M + 1) (natural number) by N.

  In pilot carrier number 0 (corresponding to carrier number 1), since a pilot signal is arranged at symbol number 1, no parameter data is assigned to the leading symbol.

  For pilot carrier number 1 (corresponding to carrier number 4), parameter data is assigned to B1 symbols from the beginning. Accordingly, in the case of FIGS. 3 to 6, since x = 1, K = 5, and N = 2, the remainder obtained by dividing x by K is “1”, and the remainder obtained by dividing “1” by N is “1”. The parameter data is assigned to the first symbol number 1. In the case of FIG. 7, since x = 1, K = 7, and N = 3, the remainder obtained by dividing x by K is “1”, and the remainder obtained by dividing “1” by N is “1”. Parameter data is assigned to the first symbol number 1. In the case of FIG. 8, since x = 1, K = 9, and N = 4, the remainder obtained by dividing x by K is “1”, and the remainder obtained by dividing “1” by N is “1”. Parameter data is assigned to the first symbol number 1. In the case of FIG. 9, since x = 2, K = 9, and N = 4, the remainder obtained by dividing x by K is “2”, and the remainder obtained by dividing “2” by N is “2”. Parameter data is assigned to the first symbol number 1 and the next symbol number 2.

  For pilot carrier number 2 (corresponding to carrier number 7), parameter data is assigned to B2 symbols from the beginning. Here, B2 is represented by B2 = (2 × x)% K% N. Accordingly, in the case of FIGS. 3 to 6, the remainder obtained by dividing 2x by K is “2”, and the remainder obtained by dividing “2” by N is “0”. It will not be assigned. In the case of FIG. 7, the remainder obtained by dividing 2x by K is “2”, and the remainder obtained by dividing “2” by N is “2”, and the parameter data is assigned to the first symbol number 1 and the next symbol number 2. Will be assigned. In the case of FIG. 8, the remainder obtained by dividing 2x by K is “2”, and the remainder obtained by dividing “2” by N is “2”, and parameter data is assigned to the first symbol number 1 and the next symbol number 2. Will be assigned. In the case of FIG. 9, the remainder obtained by dividing 2x by K is “4”, the remainder obtained by dividing “4” by N is “0”, and no parameter data is assigned to the first symbol number 1. Become.

  Also for other pilot carrier numbers, parameter data is assigned to Bi symbols from the head represented by Bi = (i × x)% K% N.

  In FIG. 12, the rear part of the symbol of pilot carrier number i has Ai = (Ps−i × x)% K symbols from the last symbol number Ps. When Ai = 1, one symbol remains, and this symbol becomes a pilot signal. Therefore, when Ai ≧ 1, parameter data is assigned to (Ai−1)% N symbols from symbol number Ps.

  Therefore, since pilot carrier number 0 is A0 = 1 in the case of FIG. 3 and FIG. 5, parameter data is not assigned to the rear symbol. In the case of FIGS. 4, 6, and 7, A0 = 2, and the remainder obtained by dividing “(2-1)” by N is “1”, and parameter data is assigned to the last symbol number Ps. It will be. In the case of FIG. 8 and FIG. 9, A0 = 3, and the remainder obtained by dividing "(3-1)" by N is "2", so that the last symbol number Ps and the symbol number (Ps- Parameter data is assigned to 1).

  In the case of FIG. 3, since A1 = 0 in the case of FIG. 3, no parameter data is assigned to the rear symbol. In the case of FIGS. 4, 7, and 9, since A1 = 1, parameter data is not assigned to the symbol of the tail portion. In the case of FIG. 6, A1 = 3, and the remainder obtained by dividing “(3-1)” by N is “0”. Therefore, parameter data is not assigned to the rear symbol. In the case of FIGS. 5 and 8, A1 = 2, and the remainder obtained by dividing “(2-1)” by N is “1”, so that the parameter data is assigned to the last symbol number Ps. .

  In the case of FIG. 3, the pilot carrier number 2 is A2 = 4, and the remainder obtained by dividing “(4-1)” by N is “1”, and parameter data is assigned to the last symbol number Ps. It will be. In the case of FIG. 6, A2 = 2, and the remainder obtained by dividing "(2-1)" by N is "1", and parameter data is assigned to the last symbol number Ps. In the case of FIG. 4 and FIG. 7, since A2 = 0, parameter data is not assigned to the rear symbol. In the case of FIGS. 5 and 8, since A2 = 1, parameter data is not assigned to the rear symbol. In the case of FIG. 9, A2 = 8, and the remainder obtained by dividing “(8-1)” by N is “3”, and parameter data is stored in the symbol numbers Ps, (Ps−1), and (Ps−2). Will be assigned.

  Also for other pilot carrier numbers, parameter data is assigned to (Ai-1)% N symbols from symbol number Ps.

  According to the present embodiment, each data block can be continuously arranged in the time direction for each carrier. In addition, parameter data is arranged for symbols to which no data is assigned. Therefore, the transmission device can transmit block-coded data and parameter data without causing a reduction in transmission capacity, and the reception device can receive without reducing the estimation accuracy of the transmission path response. Data can be demodulated. The parameter data is arranged in data carrier symbols that make assignment of data blocks difficult, and the carrier position and symbol position used for parameter data transmission are determined based on a certain rule. Therefore, since it is not necessary for the transmitting device and the receiving device to hold the random number table and determine the arrangement of the parameter data, the configuration can be simplified.

(Second Embodiment)
Next, as a second embodiment, a description will be given of an OFDM symbol configuration in the case of transmitting data that has been subjected to space frequency block coding (SFBC). In SFBC, a data block is configured by combining data carrier symbols in the carrier direction.

  FIG. 13 is a diagram for explaining the outline of the OFDM symbol configuration by the transmission apparatus according to the second embodiment of the present invention. In FIG. 13, spatial frequency block coding is performed with 2 symbols (N = 2), and data is transmitted by the SP method. In FIG. 13, the pilot signal is arranged once per (N × M + 1) carrier and once every three symbols. However, in the case of SFBC, M is the number of data blocks continuously arranged in the carrier direction, and FIG. 13 illustrates a case where M = 4. The pilot signal is arranged in each carrier with the carrier number (3n-2), and the symbol signal shift amount x between adjacent pilot carriers is “1”.

  In FIG. 13, a data block cannot be allocated to a data carrier symbol indicated by “x”. Therefore, in the present embodiment, parameter data is transmitted using data carrier symbols indicated by “x”.

  Hereinafter, a specific arrangement example of carrier symbols for transmitting parameter data according to the present embodiment will be described.

14 and 15 are configuration diagrams of OFDM symbols when the number of carriers constituting the OFDM symbol is Pc. Here, K = N × M + 1, and K carriers are called carrier blocks. In FIG. 14, K = 2 × 4 + 1 = 9 (number) carriers constitute one carrier block, and Pc is an integral multiple of K (mK). In this case, parameter data is transmitted at (symbol number 2, carrier number 1), (symbol number 2, carrier number Pc),.

  In FIG. 15, K = 2 × 4 + 1 = 9 (number of) carriers constitute one carrier block, and Pc is (integer multiple + 1) of K. In this case, parameter data is transmitted at (symbol number 2, carrier number 1), (symbol number 3, carrier number Pc),.

  In FIG. 14 and FIG. 15, “x” is located at carrier number 1 and carrier number Pc, and is located at the start carrier and end carrier of the period of the OFDM signal. Therefore, by assigning parameter data to the left end carrier and the right end carrier of the OFDM signal, it is possible to set parameters in units of the period of the OFDM signal. In particular, the case of FIG. 15 has an advantage that the number of data blocks transmitted in each OFDM symbol can be made constant.

  FIG. 16 is a flowchart showing an OFDM symbol configuration method according to the second embodiment. First, the number N of data constituting the data block is determined (step S161). Next, the number M of data blocks to be continuously arranged in the carrier direction is determined (step S162). Thereafter, the carrier number Z in which the scattered pilot is arranged for a certain symbol is determined at a K (K = N × M + 1) cycle (step S163).

  Next, the scattered pilot position determined every time the scattered pilot determined in step S163 is shifted by x in the symbol direction and y (y <K) in the carrier direction is determined as the scattered pilot position (step S164). Thereafter, M data blocks are arranged in the carrier direction except for the scattered pilot position (step S165). Then, parameter data is arranged on a carrier symbol to which no data block is assigned (step S166).

  According to the present embodiment, each data block can be continuously arranged in the carrier direction for each symbol. In addition, parameter data is arranged for symbols to which no data is assigned. Therefore, the same effect as in the first embodiment can be obtained.

  Next, an embodiment of a transmitting apparatus that transmits the OFDM symbol described in the above-described embodiment and a receiving apparatus that receives data transmitted from the transmitting apparatus will be described. In the following embodiments, a transmission device with two transmission antennas and a reception device with two reception antennas will be described. However, the number of transmission / reception antennas is not limited to this. . These transmitters and receivers are determined in combination according to SISO (Single Input Single Output), SIMO (Single Input Multiple Output), MISO (Multiple Input Single Output), and MIMO transmission form. Generally, there are one, two, and four transmission antennas and reception antennas. For example, when space-time block coding or space-frequency block coding is performed using an Alamouti code, the number of transmission antennas is generally a transmission apparatus with two transmission antennas. In addition, when space-time block coding or space-frequency block coding is performed using STBC codes by H. Jafarkahni, in general, the number of transmission antennas is four.

(Third embodiment)
FIG. 17 is a functional block diagram showing the configuration of the main part of the transmitting apparatus according to the third embodiment of the present invention. Transmitting apparatus 100 according to the present embodiment transmits a plurality of OFDM signals in the same frequency band from two transmission antennas 110-1 and 110-2, and includes error correction encoding section 120, carrier modulation section 130, A block encoding unit 140, an OFDM modulation unit 150, and RF (Radio Frequency) units 160-1 and 160-2 are provided.

  The transmission signal (bit stream) input to the transmission apparatus 100 is error correction encoded by the error correction encoding unit 120 and input to the carrier modulation unit 130. For example, the error correction encoding unit 120 uses a BCH (Bose Chaudhuri Hocquenghem) code as an outer code and an LDPC (Low Density Parity Check) code as an inner code, and performs error correction encoding on the transmission signal.

  Carrier modulation section 130 maps the error correction encoded transmission signal to the IQ plane according to a predetermined modulation scheme for each carrier (subcarrier), and outputs the result to block encoding section 140.

  The block encoding unit 140 uses the Alamouti code, for example, to perform space-time block encoding for each carrier or spatial frequency block encoding for each symbol, and outputs the signal to the OFDM modulation unit 150. To do.

  The OFDM modulation unit 150 generates an OFDM signal from the data block input from the block coding 140 and outputs the OFDM signal to the RF units 160-1 and 160-2.

  FIG. 18 is a functional block diagram illustrating a configuration of a main part of the OFDM modulation unit 150. The OFDM modulation unit 150 includes a pilot signal generation unit 151, a parameter data generation unit 152, an OFDM symbol configuration unit 153, an IFFT (Inverse Fast Fourier Transform) units 154-1 and 154-2, and a GI (Guard Interval) addition unit 155-1. , 155-2, two orthogonal modulation units 156-1 and 156-2, and D / A (Digital / Analog) conversion units 157-1 and 157-2. The IFFT units 154-1 and 154-2, the GI addition units 155-1 and 155-2, the orthogonal modulation units 156-1 and 156-2, and the D / A conversion units 157-1 and 157-2 are two transmissions. It corresponds to the antennas 110-1 and 110-2.

  Pilot signal generation section 151 generates a pilot signal having a predetermined amplitude and phase, and outputs the pilot signal to OFDM symbol configuration section 153.

  The parameter data generation unit 152 generates parameter data (eg, AC, TMCC, etc.) such as OFDM signal control information, and outputs the parameter data to the OFDM symbol configuration unit 153.

  The OFDM symbol configuration section 153 generates a pilot signal for the data block input from the block encoding section 140 of FIG. 17 according to any of the OFDM symbol configurations described in the first embodiment and the second embodiment. The pilot signal input from unit 151 and the parameter data input from parameter data generation unit 152 are inserted to generate two systems of OFDM symbols corresponding to two transmission antennas 110-1 and 110-2. In this embodiment, since two transmission antennas 110-1 and 110-2 are used, when the input data block is, for example, a space-time block coded data block, two data blocks are transmitted. Distribution is performed for each antenna, and in each OFDM symbol configuration, it is arranged at the same consecutive symbol numbers with the same carrier number. Also, in the case of being subjected to spatial frequency block coding, two data blocks are distributed for each transmission antenna and arranged in the same carrier number with the same symbol number in each OFDM symbol configuration. The OFDM symbol configuration unit 153 outputs the generated two systems of OFDM symbols to the IFFT units 154-1 and 154-2.

  IFFT sections 154-1 and 154-2 perform an IFFT (Inverse Fast Fourier Transform) process on the OFDM symbols input from OFDM symbol configuration section 153 to generate time-domain effective symbol signals, and add GI To the units 155-1 and 155-2.

  GI adding sections 155-1 and 155-2 insert the guard intervals obtained by copying the latter half of the effective symbol signals at the heads of the effective symbol signals input from IFFT sections 154-1 and 154-2, respectively, and perform orthogonal processing. It outputs to the modulation | alteration part 156-1 and 156-2. The guard interval is inserted in order to reduce intersymbol interference when receiving an OFDM signal, and is set so that the delay time of the multipath delay wave does not exceed the guard interval length.

  Quadrature modulation sections 156-1 and 156-2 perform orthogonal modulation processing on the baseband signals input from GI addition sections 155-1 and 155-2, respectively, to generate OFDM signals, and perform D / A conversion To the units 157-1 and 157-2.

  The D / A conversion units 157-1 and 157-2 convert the OFDM signals input from the orthogonal modulation units 156-1 and 156-2 into analog signals, respectively, and the RF units 160-1 and 160- in FIG. Output to 2.

  In FIG. 17, RF sections 160-1 and 160-2 respectively convert the OFDM signals input from OFDM modulation section 150 into predetermined radio frequency bands, and radiate from corresponding transmitting antennas 110-1 and 110-2. Let

  According to transmitting apparatus 100 according to the present embodiment, in OFDM symbol configuration section 153 of OFDM modulation section 150, a data block is a symbol according to any of the OFDM symbol configurations described in the first embodiment or the second embodiment. Parameter data is arranged in symbols arranged continuously in the direction or carrier direction, and data blocks cannot be arranged continuously. Therefore, block-encoded data and parameter data can be transmitted without causing a reduction in transmission capacity. The parameter data is arranged in data carrier symbols that make assignment of data blocks difficult, and the carrier position and symbol position used for parameter data transmission are determined based on a certain rule. Therefore, it is not necessary to hold the random number table and determine the arrangement of the parameter data, so that the configuration can be simplified.

  In addition, the transmission apparatus 100 mentioned above can also be functioned using a computer. In this case, the computer stores a transmission program that describes the processing contents for realizing each function of the transmission device in the storage unit of the computer, and reads and executes the transmission program by the CPU of the computer. A transmission device can be realized.

(Fourth embodiment)
FIG. 19 is a functional block diagram showing the configuration of the main part of the receiving apparatus according to the fourth embodiment of the present invention. Receiving apparatus 200 according to the present embodiment receives OFDM signals using two receiving antennas 210-1 and 210-2, and includes RF units 220-1 and 220-2, OFDM demodulating unit 230, and a block. A code decoding unit 240, a carrier demodulation unit 250, and an error correction code decoding unit 260 are provided.

  The RF units 220-1 and 220-2 convert OFDM signals in a predetermined radio frequency band into OFDM signals of a specified frequency and a specified level from the received signals received by the corresponding receiving antennas 210-1 and 210-2. To the OFDM demodulator 230.

  FIG. 20 is a functional block diagram illustrating a configuration of a main part of the OFDM demodulator 230. The OFDM demodulator 230 includes A / D converters 231-1 and 231-2, orthogonal demodulators 232-1 and 232-2, and a GI remover 233 corresponding to the two RF units 220-1 and 220-2. 1, 233-2, FFT units 234-1, 234-2, pilot signal extraction units 235-1, 235-2, transmission path response estimation units 236-1, 236-2, parameter data extraction units 237-1, 237 -2.

  The A / D conversion units 231-1 and 231-2 convert the analog signals input from the RF units 220-1 and 220-2 into digital signals, respectively, and corresponding orthogonal demodulation units 232-1 and 232-2. Output to.

  The quadrature demodulation units 232-1 and 232-2 respectively perform quadrature demodulation on the signals input from the A / D conversion units 231-1 and 231-2 to generate baseband signals, and corresponding GI removal units 233-1. , 233-2.

  The GI removal units 233-1 and 233-2 remove the guard interval from the baseband signals input from the quadrature demodulation units 231-1 and 232-2, respectively, extract effective symbol signals, and corresponding FFTs. Output to the units 234-1 and 234-2.

  The FFT units 234-1 and 234-2 perform FFT processing on the effective symbol signals input from the GI removal units 233-1 and 233-2, respectively, to generate frequency domain complex baseband signals. These complex baseband signals are output to the corresponding pilot signal extraction units 235-1 and 235-2 and parameter data extraction units 237-1 and 237-2, and also output to the block code decoding unit 240 of FIG. The

  The pilot signal extraction units 235-1 and 235-2 extract pilot signals from the complex baseband signals input from the FFT units 234-1 and 234-2, respectively, according to a predetermined OFDM symbol configuration, and correspond to them. It outputs to the transmission path response estimation part 236-1, 236-2.

  Transmission path response estimation sections 236-1 and 236-2 each estimate the transmission path response using the pilot signals extracted by pilot signal extraction sections 235-1 and 235-2, and extract the corresponding parameter data. Output to the units 237-1 and 237-2 and also to the block code decoding unit 240 of FIG.

  The parameter data extraction units 237-1 and 237-2 are input from the transmission path response estimation units 236-1 and 236-2 from the complex baseband signals input from the corresponding FFT units 234-1 and 234-2. Parameter data is extracted based on the estimation result of the transmission path response, and is output to the block code decoding unit 240 of FIG. The parameter data may be output to the demodulation unit 250 and the error correction code decoding unit 260 in FIG.

  In FIG. 19, the block code decoding unit 240 decodes the block code based on the complex baseband signal, the transmission path response estimation result, and the parameter data input from the OFDM demodulation unit 230, and the decoded result is transmitted to the carrier demodulation unit 250. Output to. The output decoding result varies depending on the combination of the block code and the error correction code, and is a complex baseband signal, LLR (Log Likelihood Ratio), or the like.

  Carrier demodulation section 250 demodulates each subcarrier using the decoding result input from block code decoding section 240, and outputs IQ data, LLR, and the like to error correction code decoding section 260.

  Error correction code decoding section 260 decodes the error correction code using values such as IQ data and LLR input from carrier demodulation section 250, and outputs a bit stream.

  According to receiving apparatus 200 according to the present embodiment, a signal transmitted according to the OFDM symbol of either the first embodiment or the second embodiment is received from the transmitting apparatus according to the third embodiment and decoded. Therefore, it is possible to perform highly accurate decoding without degrading the estimation accuracy of the transmission path response, and it is not necessary to hold the random number table, so that the configuration can be simplified.

  Note that the above-described receiving apparatus 200 can also function using a computer. In this case, the computer stores the reception program describing the processing contents for realizing each function of the reception device in the storage unit of the computer, and reads and executes the reception program by the CPU of the computer, A receiving device can be realized.

  Although the above-described embodiment has been described as a representative example, it will be apparent to those skilled in the art that many changes and substitutions can be made within the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims. For example, in the above embodiment, the pilot signal arrangement method is the scattered pilot (SP) method, but the present invention can also be effectively applied to a continuous pilot method or a pilot symbol method.

  According to the present invention, block-encoded data and parameter data using a plurality of OFDM signals in the same frequency band, with a simple configuration, without causing a reduction in transmission capacity and a reduction in estimation accuracy of a transmission path response. Therefore, it is useful for a transmission apparatus and a reception apparatus in an OFDM transmission system.

DESCRIPTION OF SYMBOLS 100 Transmitting device 110-1 to 110-4 Transmitting antenna 120 Error correction encoding unit 130 Carrier modulation unit 140 Block encoding unit 150 OFDM modulation unit 151 Pilot signal generation unit 152 Parameter data generation unit 153 OFDM symbol configuration unit 154-1 154-2 IFFT unit 155-1, 155-2 GI addition unit 156-1, 156-2 Quadrature modulation unit 157-1, 157-2 D / A conversion unit 160-1, 160-2 RF unit 200 Receiver 210 -1,210-2 Reception antennas 220-1,220-2 RF unit 230 OFDM demodulation unit 231-1, 231-2 A / D conversion unit 232-1, 232-2 Orthogonal demodulation unit 233-1, 233-2 GI removal unit 234-1, 234-2 FFT unit 235-1, 235-2 Pilot signal extraction 236-1,236-2 channel response estimation unit 237-1,237-2 parameter data extraction unit 240 block code decoding unit 250 carrier demodulation block 260 an error correction code decoding section

Claims (8)

A transmission device that transmits data using an OFDM signal,
A block encoding unit that generates a data block including N (N is a positive integer of 2 or more) pieces of data;
A pilot signal generator for generating a pilot signal for channel response estimation;
A parameter data generator for generating parameter data of the OFDM signal;
An OFDM symbol configuration unit that configures an OFDM symbol of the OFDM signal based on the data block, the pilot signal, and the parameter data, and
The OFDM symbol component is
The pilot signal is arranged in a predetermined symbol of the OFDM symbol, the data block is arranged in a data carrier symbol adjacent to the OFDM symbol, and the parameter data is arranged in a remaining data carrier symbol. Transmitter device. The block encoding unit generates the data block that is space-time block encoded,
The OFDM symbol configuration section arranges the pilot signal at a rate of once per (N × M + 1) symbols (M is a positive integer) in each pilot carrier according to a scattered pilot scheme. Item 2. The transmission device according to Item 1. The block encoding unit constitutes an OFDM symbol in which the number of OFDM symbols Ps constituting an OFDM frame is Ps = mK + (N−1), where K = (N × M + 1) and m is a positive integer. The transmission device according to claim 2, wherein: The block encoding unit generates the data block subjected to spatial frequency block encoding,
The OFDM symbol configuration section arranges the pilot signal at a rate of once per (N × M + 1) carriers (M is a positive integer) in each pilot symbol by a scattered pilot scheme. Item 2. The transmission device according to Item 1. The block encoding unit configures an OFDM symbol such that Pc = mK + (N−1), where K = (N × M + 1), where m is a positive integer, the number of carriers Pc forming the OFDM symbol. The transmission apparatus according to claim 4, wherein: A reception device that receives data transmitted from the transmission device according to any one of claims 1 to 5,
An OFDM demodulator for demodulating a received OFDM signal according to the structure of the OFDM symbol;
And a block code decoding unit that decodes a data block from the demodulated OFDM signal.   A transmission program for causing a computer to function as the transmission device according to any one of claims 1 to 5.   A receiving program for causing a computer to function as the receiving device according to claim 6.

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