JP2010062864A - Transmitter and receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmitter which is superior in power efficiency and can comparatively easily process encoding and decoding of a signal point at high speed. <P>SOLUTION: The transmitter includes: a first encoder which when a plurality of hexagons having sizes multiplied by serial natural number are drawn at the same center on an I/Q plane and a ratio of the plural hexagons is m in size, encodes data to a signal point with a power of 2 wherein 6×m signal points are arranged at apexes and on sides of the respective hexagons; and a transmitting section for transmitting transmission data based on the encoded signal points. In the transmitter, the first encoder is provided with an area calculator (901) which divides the signal points into a plurality of areas and calculates an area to which the signal points of the data among the plurality of areas belong, a range calculator (902) which calculates a hexagon to which the signal points of the data among the plurality of hexagons belong, and a position calculator (903) which calculates a position to which the signal points of the data on the hexagons belong. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a transmission device and a reception device.

  The QAM modulation scheme is a data communication scheme that represents transmission data using two-dimensional orthogonal coordinates (I / Q plane) with respect to the amplitude and phase of a carrier wave.

  Japanese Laid-Open Patent Publication No. 9-307529 discloses a spread spectrum multiplex communication method in which a plurality of data sequences are spread with a spreading code that can be distinguished from each other, and then multiplexed and transmitted. There is described a spread spectrum multiplex communication method characterized in that a phase-phase modulation method (PSK) is used and a phase plane code point arrangement after multiplexing has a hexagonal fine structure.

  In Japanese Patent Publication No. 2001-523070, a method for efficient use of improved data transmission and multi-level modulation methods that represent signals to be transmitted using orthogonal basis functions is disclosed. A method is described, characterized in that signal points having a defined signal energy are selected according to a set and / or selected probability in order to optimize the signal energy and / or data rate.

JP-A-9-307529 Special table 2001-523070 gazette

  An object of the present invention is to provide a transmission device and a reception device that have high power efficiency and can perform signal point encoding and decoding processing relatively easily and at high speed.

  The transmitting apparatus of the present invention draws a plurality of hexagons having the same center on the I / Q plane and each of which is a continuous natural number multiple, and the ratio of the sizes of the plurality of hexagons is m. A first encoder that encodes data into power-of-two signal points that sometimes arrange 6 × m signal points on the vertices and sides of each hexagon, and transmission data based on the encoded signal points The first encoder divides the signal point into a plurality of areas, and calculates an area to which the data signal point of the plurality of areas belongs, A range calculator that calculates a hexagon to which a signal point of the data belongs among a plurality of hexagons, and a position calculator that calculates a position to which the signal point of the data on the hexagon belongs.

  The receiving apparatus of the present invention includes a receiving unit that receives signals at signal points on the I / Q plane, and a plurality of natural numbers that have the same center on the I / Q plane and that are continuous in size. A hexagon is drawn, and 6 × m signal points are arranged on the vertices and sides of each hexagon when the ratio of the sizes of the plurality of hexagons is m. A first decoder that decodes the signal of the received signal point into data, wherein the first decoder divides the signal point into a plurality of areas, and the received signal point in the plurality of areas. An area calculator that calculates the area to which the signal belongs, a range calculator that calculates a hexagon to which the signal at the received signal point belongs among the plurality of hexagons, and a signal at the received signal point on the hexagon Position Cali to calculate the position to which And having a Regulator.

  By using hexagonal signal points, power efficiency is improved compared to square signal points. Further, since encoding and decoding can be performed by calculation without using a conversion table, signal point encoding and decoding processing can be performed relatively easily and at high speed.

(Reference technology)
FIG. 1 is a functional block diagram showing a configuration example of a communication system having a transmission device and a reception device in QAM (Quadrature amplitude modulation) modulation. The QAM modulation scheme is a data communication scheme that represents transmission data using two-dimensional orthogonal coordinates (I / Q plane) with respect to the amplitude and phase of a carrier wave.

  The transmission apparatus includes a serial / parallel buffer 101, a QAM encoder 102, transmission filters 103 and 104, multipliers 105 and 106, a sine / cosine table 107, an adder 108, a D / A converter 109, a post filter 110, a line driver 111, and A transmission bitmap 112 is included. The receiving apparatus includes a pre-filter 114, an A / D converter 115, an equalizer (equalizer) 116, multipliers 117 and 118, a sine / cosine table 119, reception filters 120 and 121, equalizers 122 and 123, a QAM decoder 124, and a parallel. A serial buffer 125 and a reception bitmap 126 are included. Here, a transmitting apparatus and a receiving apparatus of a transceiver facing each other via a metallic line 113 are shown.

  The serial / parallel buffer 101 stores serial transmission data for one symbol, and outputs it to the QAM encoder 102 in parallel for transmission bits according to the transmission bit map 112. The transmission bit map 112 stores the number of transmission bits of a carrier (carrier wave) determined in advance by training. The QAM encoder 102 encodes the input bit string into an I / Q signal according to the transmission bitmap 112 and outputs the I / Q signal to the transmission filters 103 and 104. The transmission filter 103 limits the band of the I signal. The transmission filter 104 limits the band of the Q signal. The sine / cosine table 107 outputs the cosine wave signal of the carrier signal to the multiplier 105, and outputs the sine wave signal of the carrier signal to the multiplier 106. Multiplier 105 multiplies the output signal of transmission filter 103 and the cosine wave signal and outputs the result. Multiplier 106 multiplies the output signal of transmission filter 104 and the sine wave signal and outputs the result. The adder 108 adds the output signals of the multipliers 105 and 106 and outputs a QAM signal. The D / A converter 109 converts the output signal of the adder 108 from digital to analog. The post filter 110 performs a filtering process on the output signal of the D / A converter 109 and outputs the result. The line driver 111 transmits the output signal of the post filter 110 to the receiving device via the metallic line 113.

  The prefilter 114 receives data via the metallic line 113 and performs a filtering process. The A / D converter 115 converts the output signal of the prefilter 114 from analog to digital. The equalizer 116 equalizes the output signal of the A / D converter 115 and takes distortion. The sine / cosine table 119 outputs the cosine wave signal of the carrier signal to the multiplier 117, and outputs the sine wave signal of the carrier signal to the multiplier 118. Multiplier 117 multiplies the output signal of equalizer 116 by the cosine wave signal and outputs an I signal. Multiplier 118 multiplies the output signal of equalizer 116 by the sine wave signal and outputs a Q signal. The reception filter 120 performs a filtering process on the I signal. The equalizer 122 equalizes the output signal of the reception filter 120. The reception filter 121 performs a filtering process on the Q signal. The equalizer 123 equalizes the output signal of the reception filter 121. The QAM decoder 124 receives the I signal and the Q signal output from the equalizers 122 and 123 and decodes them to the original data according to the reception bitmap 126. The reception bit map 126 stores the number of transmission bits of the carrier (carrier wave) determined in advance by the same training as the transmission bit map 112. The parallel / serial buffer 125 stores the output signal of the QAM decoder 124 in parallel according to the reception bitmap 126 and outputs serial reception data.

  FIG. 2 is a functional block diagram illustrating a configuration example of a communication system having a transmission device and a reception device in DMT (discrete multi-tone) modulation (G.992.1). DMT modulation is a modulation method that combines QAM modulation and fast Fourier transform, and can perform data communication at high speed. The transmission apparatus includes a serial / parallel buffer 201, an encoder 202, an inverse fast Fourier transformer 203, a parallel / serial buffer 204, a D / A converter 205, and a transmission bitmap 206. The receiving apparatus includes an A / D converter 208, a time domain equalizer 209, a serial / parallel buffer 210, a fast Fourier transformer 211, a frequency domain equalizer 212, a decoder 213, a parallel / serial buffer 214, and a reception bitmap 215. Here, a transmitter and a receiver of a transceiver are shown in the direction from the station side facing the subscriber via the metallic line 207 to the subscriber side (downward direction).

  The serial / parallel buffer 201 stores transmission data for one symbol, divides the transmission data into the number of transmission bits per carrier determined in advance by training and stored in the transmission bit map 206, and outputs the divided data to the encoder 202. The encoder 202 encodes the input bit string of each carrier into signal point data (I signal and Q signal) for QAM modulation for each carrier according to the transmission bitmap 206, and performs inverse fast Fourier transform. Output to the converter 203. The inverse fast Fourier transformer 203 performs the inverse fast Fourier transform, thereby performing orthogonal amplitude transformation for each signal point, and outputs the result to the parallel / serial buffer 204. Here, the parallel / serial buffer 204 adds a total of 32 samples of 480 to 511 samples of the output signal of the inverse fast Fourier transformer 203 to the head of the DMT symbol as a cyclic prefix. This is a guard interval signal period for making the receiving apparatus side invisible the influence of the disturbance of the signal waveform at the DMT symbol boundary. The parallel / serial buffer 204 sequentially outputs 512 + 32 pieces of sample data to the D / A converter 205 sequentially. The D / A converter 205 converts the input digital data into an analog signal at a sampling frequency of 2.208 MHz, and transmits it to the receiving device (subscriber) side via the metallic line 207.

  On the receiving device side, the A / D converter 208 receives a signal from the transmitting device via the metallic line 207, converts the input analog signal into a 2.208 MHz digital signal, and outputs the digital signal to the time domain equalizer 209. The time domain equalizer 209 performs digital signal processing on the input data so that the intersymbol interference (ISI) falls within the 32-sample cyclic prefix, and outputs the processing effect data to the serial / parallel buffer 210. The serial / parallel buffer 210 stores data for 1 DMT symbol, then removes samples for the cyclic prefix and outputs 512 sample data to the fast Fourier transformer 211. The fast Fourier transformer 211 performs fast Fourier transform, generates (demodulates) 256 signal points, and outputs the signal points to the frequency domain equalizer 212. The frequency domain equalizer 212 performs inter-channel interference compensation processing on the demodulated 256 signal point data, and outputs the result to the decoder 213. The decoder 213 decodes the signal point data of each carrier according to the reception bitmap 215 that holds the same value as the transmission bitmap 206, and outputs the data obtained by the decoding to the parallel / serial buffer 214. The parallel / serial buffer 214 stores data according to the reception bitmap 215 and outputs the reception data in bit serial.

FIG. 3 is a diagram showing signal point arrangement on the I / Q plane in 16QAM modulation. QAM modulation is a method of expressing signal points by assigning data to each of the I and Q signals and treating them as orthogonal coordinates. For example, data v = {v _b−1 , v _b−2 ,. . . , V ₁ , v ₀ }, the signal point (X, Y) on the I / Q plane is represented by X = {v _b−1 , v _b−3 ,. . . , V ₃ , v ₁ , 1}, Y = {v _b-2 , v _b-4 ,. . . , V ₂ , v ₀ , 1} are signed binary values represented by bit strings.

  Therefore, as shown in the example of FIG. 3, the signal points are arranged in a square on the I / Q plane. Since the value of the I signal and the value of the Q signal are data to be transmitted as they are, the modulation and demodulation processes are simple.

  FIG. 4 is a block diagram illustrating a configuration example of the QAM decoder 124. The QAM decoder 124 inputs data of the I signal and Q signal output from the equalizers 122 and 123. The I signal data and the Q signal data are alternately rearranged bit by bit by the conversion buffer 401. The rearranged data is output as received data.

  FIG. 6 is a diagram for explaining power efficiency in QAM modulation. The sending power is set as the upper limit in the laws and regulations of various countries and various standards. This is a circle of a certain size on the I / Q plane. The QAM modulation method, which is frequently applied to applications that perform high-speed data transmission such as DMT modulation, generates a power region 601 in which signal points are not arranged in terms of power efficiency. Therefore, there is a problem that it is not necessarily an optimal modulation system for the purpose of performing data transmission at high speed.

  FIG. 13 is a diagram illustrating an example of signal point arrangement in a modulation scheme of signal point arrangement aiming at power efficiency. As a transmission method that is efficient in terms of power, as a method of arranging many signal points within a certain power and increasing data transmission efficiency, the signal points are drawn so that the signal points draw a hexagon on the I / Q plane. Hexagonal arrangement. In such signal point arrangement, since the number of signal points may take a value other than a power of 2, a method of allocating data by re-encoding data by the Huffman method or the like can be considered.

  FIG. 7 is a functional block diagram showing a configuration example of a QAM modulation scheme communication system having a transmission apparatus and a reception apparatus for performing the signal point arrangement of FIG. The communication system of FIG. 7 is different from the communication system of FIG. 1 in that a signal point encoder 702, a transmission coordinate conversion table 712, a signal point are used instead of the QAM encoder 102, the transmission bitmap 112, the QAM decoder 124, and the reception bitmap 126. A decoder 724 and a reception coordinate conversion table 726 are included.

  FIG. 5 is a block diagram illustrating a configuration example of the signal point decoder 724 and the reception coordinate conversion table 726 of FIG. The signal point decoder 501 corresponds to the signal point decoder 724 in FIG. 7, and the reception coordinate conversion table 502 corresponds to the reception coordinate conversion table 726 in FIG. The signal point decoder 501 receives the I signal data and the Q signal data, compares the values of the I signal and the Q signal with the I signal and the Q signal in the reception coordinate conversion table 502, and if they match, receives the corresponding bit string. Output as data.

  In the decoding process, in order for the signal point decoder 502 to decode the data corresponding to the signal point, the coordinates on the I / Q plane of the signal point are converted into a received coordinate conversion table indicating the correspondence between the signal point and the data. Processing is performed in comparison with 502. In particular, in an application that performs high-speed data transmission, when data transmission is performed using a large number of signal points, the number of rows 503 in the reception coordinate conversion table 502 that associates data with signal point coordinates becomes enormous. . Further, since the reception coordinate conversion table 502 is required for the number of combinations of signal points, when a combination of signal points suitable for the signal-to-noise ratio of the transmission path is used, a corresponding number of reception coordinate conversions for a number 504 are performed. Table 502 needs to be prepared.

  For this reason, not only the circuit scale increases due to the reception coordinate conversion table 502, but also the number of processings for comparing the signal point coordinates with the table increases in the decoding process, which takes processing time. Also, in the modulation scheme in which the signal points are arranged in a hexagonal shape for the purpose of power optimization, the number of bits transmitted in one symbol by re-encoding in order to cope with the case where the signal points are not a power of 2. Changes.

  The signal point encoder 702 in FIG. 7 performs a process of converting the input bit string into the signal point coordinates of the transmission data according to the transmission coordinate conversion table 712 in the reverse procedure of the signal point decoder 501 shown in FIG. Do.

  FIG. 8 is a functional block diagram showing a configuration example of a DMT modulation scheme communication system having a transmission apparatus and a reception apparatus for performing the signal point arrangement of FIG. The communication system in FIG. 8 is different from the communication system in FIG. 2 in that a signal point encoder 802, a transmission signal point set map 806, and a signal point decoding are used instead of the encoder 202, the transmission bitmap 206, the decoder 213, and the reception bitmap 215. And a received signal point set map 815. The DMT modulation communication system shown in FIG. 8 is a communication system in which the signal point arrangement method with improved power efficiency shown in FIG. 13 is applied to a system that multiplexes carrier frequencies using the fast Fourier transformer shown in FIG. is there.

  The serial / parallel buffer 201 stores transmission data for one symbol, and divides it into the number of bits corresponding to the signal point arrangement for each carrier, which is determined in advance by training and stored in the transmission signal point set map 806. To the signal point encoder 802.

  However, in the constellation method with improved power efficiency shown in FIG. 13, the number of signal points may not be a power of 2. In such a carrier, the number of bits transmitted by the signal point encoder 802 is dynamically changed. It is necessary to let

  Also, the number of bits corresponding to the transmission data for one symbol changes dynamically depending on the contents of the transmission data, so that the buffer can be made larger, or the buffer underflow or overflow can be absorbed. It is necessary to incorporate a control circuit in consideration of the above.

  The signal point encoder 802 transmits the input bit string of each carrier for each carrier according to the transmission signal point set map 806 of each carrier in the reverse procedure of the signal point decoder 501 shown in FIG. Data is converted into signal point coordinates and output to the inverse fast Fourier transformer 203.

  Thereafter, the path and operation from the inverse fast Fourier transformer 203 of the transmission device to the frequency domain equalizer 212 of the reception device are the same as those in the DMT modulation described in FIG. Data that has been subjected to inter-channel interference compensation processing by frequency domain equalizer 212 is input to signal point decoder 813.

  The signal point decoder 813 decodes the signal point data of each carrier for each carrier according to the method shown in FIG. 5 according to the reception signal point set map 815 that holds the same value as the transmission signal point set map 806. Data obtained by decoding is stored in the parallel / serial buffer 214.

  However, in the signal point arrangement method with improved power efficiency shown in FIG. 13, the number of signal points may not be a power of 2. Depending on the position of the received signal point and the content of data to be transmitted in such a carrier. Therefore, it is necessary to dynamically change the number of bits stored in the parallel / serial buffer 214.

  Therefore, since the number of bits for one symbol input to the parallel / serial buffer 214 changes dynamically depending on the contents of the transmission data, a buffer of a larger size or a buffer size can be used to absorb the change. It becomes necessary to incorporate a control circuit in consideration of underflow and overflow. Therefore, the parallel / serial buffer 214 in FIG. 8 has a complicated circuit configuration that operates at a higher speed than the parallel / serial buffer 214 in FIG.

  Therefore, when the signal point arrangement method with improved power efficiency shown in FIG. 13 is applied to a system in which a plurality of carriers are multiplexed and transmitted in order to increase the data transmission speed, the circuit configuration of the system tends to be complicated. is there.

  In the following, it has a signal point arrangement that is improved in terms of power efficiency compared to the above-mentioned modulation method, and the signal point can be encoded and decoded relatively easily and at a high speed. An embodiment of a data communication method applicable to an application to be performed will be described.

(First embodiment)
14 to 17 are diagrams for explaining a signal point arrangement method of the communication system according to the first embodiment of the present invention. In the signal point arrangement method of this embodiment, first, on the I / Q plane, hexagons having the same center and a continuous natural number of multiples such as 1, 2,..., N are drawn. 6 × n signal points are arranged at equal intervals on the vertices and sides of the hexagon. For example, there are 6 signal points on the hexagon 1402 and 12 signal points on the hexagon 1403. Therefore, although the arrangement is close to a hexagonal fine arrangement, the signal point 1401 at the center position is not used in this embodiment.

  In the signal point arrangement method of the present embodiment, the signal points in FIG. 14 are divided into six signal point areas 1501 to 1506 shown in FIG. These signal point areas 1501 to 1506 include the same number of signal points, and are divided into areas so that the signal point areas draw a triangle. Here, the signal point areas 1501 and 1502, 1503 and 1504, or 1505 and 1506 are treated as a set. That is, two signal point areas sandwiching the center form a set.

  Then, two signal points are selected from these sets so that the number of signal points used for transmission is a power of two. For example, two points are selected from the set of signal point areas 1501 and 1502, two points from the set of signal point areas 1503 and 1504, and two points from the set of signal point areas 1505 and 1506. Subsequently, the signal point areas 1501 and 1502 are selected in order. In the set of signal point areas 1501 and 1502, for example, one point from the signal point area 1501 and one point from the signal point area 1502 are allocated in an equal order. In this rule, for example, signal points may be selected one by one in the order of signal point areas 1502, 1501, 1503, 1504, 1506, and 1505.

  Next, the selection order of signal points to be used in one signal point area will be described with reference to FIG. Since each signal point area is symmetrical, the arrangement method in the other signal point areas may be performed by rotating the arrangement method of one signal point area. Here, in one signal point area 1601, Only the signal point selection order will be described.

  First, since a signal point on the hexagon on the side closer to the center is selected, the signal point first selected is the signal point 1611. It is not a signal point 1604. The signal point 1605 is selected as a signal point used for transmission after all the signal points 1606, 1607, 1608, 1609, and 1610 are selected as signal points used for transmission.

  The signal points 1606, 1607, 1608, 1609 and 1610 are placed on the same hexagon, but these are selected as signal points to be used for transmission from the signal point closer to the center 1602 of the side. Either of signal points 1608 and 1609 may be first. For example, the order of signal points 1608, 1609, 1607, 1610, 1606 may be used. Also, the order of signal points 1609, 1608, 1610, 1607, 1606 may be used. Since the signal point 1606 is farthest from the center 1602 of the side among the five signal points, it is always the last.

  In this way, when the number of signal points used for transmission is selected to a power of 2, the arrangement of signal points used for transmission is as shown in FIG. That is, the signal point 1701 at the center position and the signal point 1702 near the outermost vertex are missing from the hexagonal signal points arranged in a hexagonal manner. When the signal is actually transmitted, the signal is transmitted in a state in which the size is normalized in accordance with the upper limit power 1703 defined by standards, laws and regulations.

  When a large number of bits are transmitted by one carrier, the distance between signal points is wider than the method such as QAM modulation in FIG. 3 at the same transmission speed. That is, noise resistance is increased. In other words, there is a possibility that higher-speed transmission can be realized under the same noise environment.

  FIG. 18 is a diagram for explaining the power efficiency of the signal point arrangement method according to the present embodiment. Signal point arrangement (FIGS. 14 to 17) 1802 at the time of 6-bit transmission according to this embodiment and 64QAM (QAM modulation). The signal point arrangement (FIG. 3) 1801 at the time of 6-bit transmission) is shown. In this embodiment, the signal point arrangement 1802 is indicated by a white circle (◯), and the 64QAM signal point arrangement 1801 is indicated by a black circle (●). In this state, if the symbol rate is the same, the transmission rate is the same between the signal arrangement 1801 of 64QAM and the signal arrangement 1802 of the present embodiment. The shortest distance 1803 between signal points in the QAM modulation signal point arrangement 1801 is relatively short. On the other hand, in the signal point arrangement 1802 of this embodiment, since the signal points are arranged up to the unused area 601 (FIG. 6) in QAM modulation, the shortest distance 1804 between the signal points can be made longer.

  FIG. 11 is a functional block diagram illustrating a configuration example of a communication system including the transmission device and the reception device according to the present embodiment. The communication system of FIG. 11 can be realized by replacing the QAM encoder 102 and the QAM decoder 124 with a new encoder 1102 and a new decoder 1124 in the communication system of FIG. Hereinafter, differences between the communication system of FIG. 11 and the communication system of FIG. 1 will be described.

  9A and 9B are diagrams illustrating a configuration example of the new encoder 1102 in FIG. As shown in FIG. 15, the area calculator 901 calculates an area number area # indicating which of the areas obtained by dividing the I / Q plane into 6 from the input transmission data, and the I / Q Output to the position calculator 904. This area number area # is the remainder of dividing the input data by 6. The area calculator 901 calculates a quotient k obtained by dividing the input data by 6 and outputs the quotient k to the range calculator 902.

  As shown in FIG. 17, the range calculator 902 calculates a range number range # indicating the size of a hexagon drawn on the I / Q plane on which the signal point to be found is placed, from the input data, Output to the Q position calculator 904. The range number range # is the smallest integer r that satisfies k ≦ r (r−1) / 2, where k is the input of the range calculator 902. The range calculator 902 calculates a value of m that satisfies m = k−r (r−1) / 2, and outputs the value to the position calculator 903 together with the range number range #.

  The position calculator 903 calculates a position number position # which is a value calculated based on the apex position as to which position on the hexagon drawn on the I / Q plane the signal point should be from the input data. To do. The quotient c obtained by dividing the range number range # by 2 is the position of the signal point in the vicinity of the center of the hexagonal side with respect to the vertex of the hexagon. Further, the position calculator 903 sets a value obtained by multiplying a quotient obtained by dividing a value obtained by adding 1 to the input value m from the range calculator 902 by 2 by a sign s obtained based on the table of FIG. Calculate position # = c + d. Then, the position calculator 903 outputs the calculated position number position # to the I / Q position calculator 904.

  The I / Q position calculator 904 calculates signal point coordinates based on the input numbers area #, range #, and position #, and outputs an I signal value and a Q signal value, respectively. The calculation obtains a temporary I signal value I and a Q signal value Q as in the following equation, and calculates the I signal value and the I signal value by rotating to the coordinates of the corresponding region according to the area number area #. The Q signal value can be obtained.

I = range #-(position # ÷ 2)
Q = √3 ÷ 2 × position #

  FIG. 10 is a diagram illustrating a configuration example of the new decoder 1124 in FIG. 11, and shows a decoder corresponding to the encoder 1102 in FIG. The discrete calculator 1001 receives the I signal value and the Q signal value, multiplies the I signal value by 2, multiplyes the Q signal value by √3, and takes an integer value to quantize the data. The quantized data is output to the area calculator 1002.

  The area calculator 1002 calculates the area number area # based on the sign of the I signal value and the Q signal value and the absolute value, and outputs the area number area # to the value decoder 1005. The area calculator 1002 performs appropriate rotation processing on the I signal value and the Q signal value from the area number area #, and outputs the result to the range calculator 1003.

  The range calculator 1003 calculates the range number range # indicating the size of the hexagon drawn on the I / Q plane on which the received signal point is located from the I signal value and the Q signal value, and the position on the side of the hexagon. d. The range calculator 1003 outputs the range number range # to the value decoder 1005, and outputs the range number range # and the position d to the position calculator 1004.

  The position calculator 1004 calculates the position number position # indicating the number of data on the side from the position d on the side, and outputs the position number position # to the value decoder 1005.

  The value decoder 1005 performs a calculation for decoding the data from the input numbers area #, range #, and position #. Specifically, data data is calculated by the following equation.

    data = 6 × (position # + range # × (range # + 1) ÷ 2) + area #

  As described above, in the transmission apparatus according to the present embodiment, the new encoder (first encoder) 1102 has a plurality of hexagons having the same center on the I / Q plane and a natural number that is a multiple of each size. , And when the ratio of the sizes of the plurality of hexagons is m, data is encoded into 6 × m signal points that are arranged on the vertices and sides of each hexagon. . The transmission unit includes a D / A converter 109, a post filter 110, and a line driver 111, and transmits transmission data based on the encoded signal points.

  The new encoder 1102 divides the signal points into a plurality of areas, calculates an area to which the data signal points of the plurality of areas belong, and a signal of the data of the plurality of hexagons A range calculator 902 that calculates a hexagon to which the point belongs, and a position calculator 903 that calculates a position to which the signal point of the data on the hexagon belongs.

  The area calculator 901 divides the signal point into six triangular areas, and the two triangular areas facing each other at the center of the hexagon determine the signal power of the power of 2 by selecting the same number of signal points. The triangular area to which the signal points of the data belong is calculated.

  The range calculator 902 selects the signal points in order from the signal point located on the inner hexagon of the plurality of hexagons to the signal point located on the outer hexagon. A power point is determined, and a hexagon to which the data signal point belongs is calculated.

  The position calculator 903 determines the signal point of the power of 2 by selecting signal points in order from the signal point closest to the center of the hexagonal side to the signal point on the vertex of the hexagon. The position to which the data signal point belongs is calculated.

  In the receiving apparatus of this embodiment, the receiving unit includes the prefilter 114, the A / D converter 115, and the equalizer 116, and receives signals at signal points on the I / Q plane. The new decoder 1124 draws a plurality of hexagons having the same center on the I / Q plane, each of which has a continuous natural number multiple, and the ratio of the sizes of the plurality of hexagons is m. 6 × m signal points are decoded into data from signals of the received signal points among signal points of powers of 2 arranged on the vertices and sides of each hexagon. The new decoder 1124 divides the signal points into a plurality of areas, calculates an area to which the signal of the received signal point belongs among the plurality of areas, and the reception of the plurality of hexagons. A range calculator 1003 for calculating a hexagon to which the signal of the signal point belongs, and a position calculator 1004 for calculating a position to which the signal of the received signal point on the hexagon belongs.

  According to the present embodiment, by using hexagonal signal points, power efficiency is improved compared to square signal points. Further, since encoding and decoding can be performed by calculation without using a conversion table, signal point encoding and decoding processing can be performed relatively easily and at high speed.

(Second Embodiment)
FIG. 12 is a functional block diagram illustrating a configuration example of a communication system including a transmission device and a reception device according to the second embodiment of the present invention. The communication system of FIG. 12 can be realized by replacing the encoder 202 and the decoder 213 with a new encoder 1202 and a new decoder 1213 in the communication system of FIG. The new encoder 1202 and the new decoder 1213 perform the same processing as the new encoder 1102 and the new decoder 1124 in FIG.

  A new encoder (first encoder) 1202 encodes data into signal points for each carrier. The inverse fast Fourier transformer 203 performs inverse fast Fourier transform on the signal points for each carrier encoded by the new encoder 1202. The transmission unit includes a D / A converter 205 and transmits transmission data based on the signal points subjected to the inverse fast Fourier transform.

  The receiving unit includes an A / D converter 208 and a time domain equalizer 209, and receives signals at signal points for each carrier. The fast Fourier transformer 211 performs fast Fourier transform on signal points for each carrier. The new decoder (first encoder) 1213 decodes the signal of the signal point for each carrier subjected to the fast Fourier transform into data.

(Third embodiment)
FIG. 19 is a functional block diagram illustrating a configuration example of a communication system including a transmission device and a reception device according to the third embodiment of the present invention. The communication system of FIG. 19 is obtained by adding a new encoder 1102, a new decoder 1124, and selectors 1901, 1902 to the communication system of FIG. The new encoder 1102 is the same as the new encoder 1102 of FIG. 11, and the new decoder 1124 is the same as the new decoder 1124 of FIG. Hereinafter, differences of the present embodiment from the communication system of FIG. 1 will be described.

  A new encoder (first encoder) 1102 receives data from the serial / parallel buffer 101, encodes input data according to the transmission bitmap 112, and outputs an I signal and a Q signal to the selector 1901. Specifically, as shown in FIGS. 14 to 17, the new encoder 1102 draws a plurality of hexagons having the same center on the I / Q plane, each of which is a natural number of multiples that are continuous. When the ratio of the sizes of a plurality of hexagons is m, the data is encoded to a power of 2 that places 6 × m signal points on the vertices and sides of each hexagon.

  A QAM encoder (second encoder) 102 receives data from the serial / parallel buffer 101, encodes input data according to the transmission bitmap 112, and outputs an I signal and a Q signal to the selector 1901. Specifically, as shown in FIG. 3, the QAM encoder 102 encodes data into signal points of powers of 2 that are arranged in a square grid with equal vertical and horizontal intervals on the I / Q plane.

  The selector 1901 selects either the new encoder 1124 or the QAM encoder 102 based on the number of signal points in the transmission bitmap 112 and outputs the I signal and the Q signal to the transmission filters 103 and 104. For example, the selector 1901 selects the QAM encoder 102 when the number of signal points is small, and selects the new encoder 1102 when the number of signal points is large.

  The QAM decoder 124 receives the I signal and the Q signal from the equalizers 122 and 123, decodes the I signal and the Q signal into data according to the reception bitmap 126, and outputs the data to the selector 1902. Specifically, as shown in FIG. 3, the QAM decoder 124 decodes signal powers of powers of 2 arranged in a square lattice with equal vertical and horizontal intervals on the I / Q plane into data. The selector 1902 selects either the new decoder 1124 or the QAM decoder 124 based on the number of signal points in the reception bitmap 126 and outputs the data to the parallel / serial buffer 125.

  The present embodiment can also be applied to the communication system of FIG. That is, a new encoder 1202, a new decoder 1213, and selectors 1901, 1902 can be added to the communication system of FIG. The new encoder 1202 is the same as the new encoder 1202 of FIG. 12, and the new decoder 1213 is the same as the new decoder 1213 of FIG. The selector 1901 selects either the new encoder 1202 or the QAM encoder 202 based on the number of signal points in the transmission bitmap 206 and outputs the I signal and Q signal for each carrier to the inverse fast Fourier transformer 203. For example, the selector 1901 selects the QAM encoder 202 when the number of signal points is small, and selects the new encoder 1202 when the number of signal points is large.

  The decoder 213 receives the I signal and the Q signal from the equalizer 212, decodes the I signal and the Q signal for each carrier into data according to the reception bitmap 215, and outputs the data to the selector 1902. Specifically, as shown in FIG. 3, the decoder 213 decodes data signals of powers of 2 arranged in square grids having equal vertical and horizontal intervals on the I / Q plane. The selector 1902 selects either the new decoder 1213 or the decoder 213 based on the number of signal points in the reception bitmap 215 and outputs the data to the parallel / serial buffer 214.

  As described above, according to the first to third embodiments, unlike the signal point arrangement method of FIG. 5, the relationship between data and signal point coordinates can be obtained by relatively simple arithmetic processing. Therefore, even when a large number of signal points are arranged particularly in the decoder of the receiving apparatus, a circuit that can be processed at high speed with a simple configuration can be created.

  In addition, signal points can be arranged at locations close to hexagonal fineness with good power efficiency by simple arithmetic processing. Thereby, in a high-speed communication system, communication with higher speed and stronger noise resistance can be realized.

  In the second embodiment, for a high-speed communication system using a plurality of carriers, a signal point encoding and decoding process is realized by a simple calculation, thereby realizing a transmission with higher speed and stronger noise tolerance. be able to.

  In the third embodiment, even in a high noise environment where a large number of signal points cannot be arranged, an inefficient point in the case where the number of signal points is small can be avoided, and a high-speed communication system can be realized without reducing efficiency. . Also, in a high-speed communication system that uses multiple carriers, even if there are carriers in a high noise environment, transmission can be performed with more optimal power efficiency, and transmission with higher speed and higher noise tolerance can be realized. be able to.

  The above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

It is a functional block diagram which shows the structural example of the communication system which has a transmitter and receiver in QAM modulation. It is a functional block diagram which shows the structural example of the communication system which has the transmitter and receiver in DMT modulation. It is a figure which shows signal point arrangement | positioning on the I / Q plane in 16QAM modulation. It is a block diagram which shows the structural example of a QAM decoder. It is a block diagram which shows the structural example of the signal point decoder of FIG. 7, and a receiving coordinate conversion table | surface. It is a figure explaining the power efficiency in QAM modulation. It is a functional block diagram which shows the structural example of the QAM modulation system communication system which has a transmitter and receiver for performing the signal point arrangement | positioning of FIG. It is a functional block diagram which shows the structural example of the DMT modulation system communication system which has a transmitter and receiver for performing the signal point arrangement | positioning of FIG. 9A and 9B are diagrams showing a configuration example of the new encoder of FIG. It is a figure which shows the structural example of the new decoder of FIG. It is a functional block diagram which shows the structural example of the communication system which has a transmitter and receiver by the 1st Embodiment of this invention. It is a functional block diagram which shows the structural example of the communication system which has a transmitter and receiver by the 2nd Embodiment of this invention. It is a figure which shows the example of the signal point arrangement | positioning in the modulation system of the signal point arrangement | positioning aiming at power efficiency improvement. It is a figure for demonstrating the signal point arrangement | positioning method of the communication system by the 1st Embodiment of this invention. It is a figure for demonstrating the signal point arrangement | positioning method of the communication system by the 1st Embodiment of this invention. It is a figure for demonstrating the signal point arrangement | positioning method of the communication system by the 1st Embodiment of this invention. It is a figure for demonstrating the signal point arrangement | positioning method of the communication system by the 1st Embodiment of this invention. It is a figure for demonstrating the power efficiency of the signal point arrangement | positioning method by the 1st Embodiment of this invention. It is a functional block diagram which shows the structural example of the communication system which has a transmitter and receiver by the 3rd Embodiment of this invention.

Explanation of symbols

101 Serial / Parallel Buffer 102 QAM Encoder 103, 104 Transmission Filter 105, 106 Multiplier 107 Sine / Cosine Table 108 Adder 109 D / A Converter 110 Post Filter 111 Line Driver 112 Transmission Bitmap 113 Metallic Line 114 Prefilter 115 A / D converter 116, 122, 123 Equalizer 117, 118 Multiplier 119 Sine / cosine table 120, 121 Reception filter 124 QAM decoder 125 Parallel / serial buffer 126 Reception bitmap 1102 New encoder 1124 New decoder 901 Area calculator 902 Range calculator 903 Position calculator 904 I / Q position calculator

Claims (7)

On the I / Q plane, draw a plurality of hexagons having the same center and a natural number of multiples of each size, and the ratio of the sizes of the hexagons is 6 × m. A first encoder that encodes data into power-of-two signal points that place signal points on the vertices and sides of each hexagon;
A transmission unit for transmitting transmission data based on the encoded signal points,
The first encoder is
An area calculator that divides the signal points into a plurality of areas and calculates an area to which the data signal points of the plurality of areas belong;
A range calculator for calculating a hexagon to which a signal point of the data of the plurality of hexagons belongs;
And a position calculator for calculating a position to which a signal point of the data on the hexagon belongs.   The area calculator divides the signal point into six triangular areas, and two triangular areas facing each other at the center of the hexagon determine the signal power of the power of 2 by selecting the same number of signal points. 2. The transmission apparatus according to claim 1, wherein a triangular area to which the data signal point belongs is calculated.   The range calculator selects the signal points in order from a signal point located on an inner hexagon of the plurality of hexagons to a signal point located on an outer hexagon. 3. The transmitting apparatus according to claim 1, wherein a signal point of a power is determined and a hexagon to which the data signal point belongs is calculated.   The position calculator determines a signal point of the power of 2 by selecting a signal point in order from the signal point closest to the center of the hexagonal side to the signal point on the vertex of the hexagon, The transmission apparatus according to claim 1, wherein a position to which the data signal point belongs is calculated. The first encoder encodes the data into signal points for each carrier;
And an inverse fast Fourier transformer that performs inverse fast Fourier transform on the signal points of each carrier encoded by the first encoder,
The transmission device according to any one of claims 1 to 4, wherein the transmission unit transmits transmission data based on the signal points subjected to the inverse fast Fourier transform. A second encoder that encodes data into power-of-two signal points arranged in a square grid of equal vertical and horizontal spacing on the I / Q plane;
The transmission apparatus according to claim 1, further comprising: a selector that selects one of the first encoder and the second encoder. A receiving unit that receives signals at signal points on the I / Q plane;
On the I / Q plane, draw a plurality of hexagons having the same center and a natural number of multiples of each size, and the ratio of the sizes of the hexagons is 6 × m. A first decoder that decodes the received signal point signal to data among signal powers of powers of 2 placed on the vertices and sides of each hexagon;
The first decoder comprises:
An area calculator that divides the signal points into a plurality of areas and calculates an area to which the signal of the received signal points belongs among the plurality of areas;
A range calculator for calculating a hexagon to which a signal of the received signal point belongs among the plurality of hexagons;
And a position calculator for calculating a position to which a signal of the received signal point on the hexagon belongs.

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