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WO2009006812A1 - Encoding modulation method,decoding method and apparatus of trellis coded modulation code - Google Patents

Encoding modulation method,decoding method and apparatus of trellis coded modulation code Download PDF

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Publication number
WO2009006812A1
WO2009006812A1 PCT/CN2008/071349 CN2008071349W WO2009006812A1 WO 2009006812 A1 WO2009006812 A1 WO 2009006812A1 CN 2008071349 W CN2008071349 W CN 2008071349W WO 2009006812 A1 WO2009006812 A1 WO 2009006812A1
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Prior art keywords
constellation
bit
constellation map
code
tcm
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PCT/CN2008/071349
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French (fr)
Chinese (zh)
Inventor
Dongmei Fang
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Huawei Technologies Co., Ltd.
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Publication of WO2009006812A1 publication Critical patent/WO2009006812A1/en

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    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03MCODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H03M13/25Error detection or forward error correction by signal space coding, i.e. adding redundancy in the signal constellation, e.g. Trellis Coded Modulation [TCM]
    • H03M13/256Error detection or forward error correction by signal space coding, i.e. adding redundancy in the signal constellation, e.g. Trellis Coded Modulation [TCM] with trellis coding, e.g. with convolutional codes and TCM
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03MCODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H03M13/25Error detection or forward error correction by signal space coding, i.e. adding redundancy in the signal constellation, e.g. Trellis Coded Modulation [TCM]
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03MCODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H03M13/27Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes using interleaving techniques
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03MCODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H03M13/31Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes combining coding for error detection or correction and efficient use of the spectrum

Definitions

  • the invention belongs to the technical field of data coding, and in particular relates to a code modulation and decoding method and device for a trellis coded modulation code. Background technique
  • TCM (Trellis coded modulation) coding or trellis coded modulation technology
  • trellis coded modulation technology is a "signal set space coding" that can encode and modulate without reducing the band utilization and power utilization. Combined, the redundancy of the signal set is used to obtain error correction capability.
  • the number of signal points used in the constellation diagram is greater than the number of points required to encode the same type of modulation. These additional signal points provide redundancy for error correction coding.
  • TCM The basic idea of TCM is to use an extended signal set to provide controllable coding redundancy, and to design convolutional coding and multi-modulation mapping uniformly, that is, to perform hierarchical segmentation mapping on the transmitted signal point set to make the coded signal sequence free.
  • Euclidean distance the squared Euclidean distance is the square of the distance between two signal points, the cylinder is called the Euclidean distance
  • the free Euclidean distance is defined as the bifurcation from the same state at zero time, and the two at the subsequent time have a convergence
  • the TCM signal is generated as follows: At a time n, the original bit block of length k enters the encoder, and one of them enters the convolutional encoder bit ( ⁇ k) through a code rate.
  • the convolutional encoder is expanded into a coded ratio of the encoded bits. Special group, the m coded bits are used to select one of the subsets of the 2 k+m - k modulation signal set, and the remaining pass bits form an uncoded bit group for use in the subset Select one of the 1" signal points as the final transmitted TCM signal.
  • the division principle of the above subset (also called the set division principle) is of great significance in the construction of the TCM scheme.
  • the so-called set segmentation is to divide a signal set into smaller subsets one after another, and to maximize the minimum Euclidean distance in the segmented subset.
  • the minimum Euclidean distance between the signal points should increase step by step.
  • the modulation signal set with 2 " ⁇ signal points is divided into m stages. Let the subset ⁇ after the i-th stage division, the inner minimum Euclidean distance is ⁇ ' ⁇ ( ⁇ 0 ' 1 '"'' m )
  • the number of encoded bits corresponding to the signal points in the same subset is . . . 3 is the same (it can be said that the same signal points corresponding to the bit groups after encoding correspond to the same subset ), and in order to distinguish 2 "signal points in the same subset, the corresponding uncoded bit groups of each signal point must be different.
  • the coding ratio The 1" signal points of the same group belong to the same subset, and the corresponding - uncoded bit groups must be different.
  • all subsets need to conform to the set partitioning principle.
  • FIG. 2 is a schematic diagram of a set division of a 16QAM (quarature amplitude modulation) signal point set.
  • All modulated signals should have the same frequency of occurrence and should have as much regularity and symmetry as possible. This principle indicates that a good TCM code should have a regular structure. This is because the TCM scheme is actually a scheme for optimal segmentation of the signal space, and the modulation signal space is symmetric, so the optimal segmentation scheme should also Regular and symmetrical.
  • the corresponding signal of the branching branch starting from the same state shall belong to the same subset ⁇ after the first level set. Or ⁇ ⁇ , which guarantees that the distance between different branches separated from the same state is greater than or equal to ⁇ ⁇ .
  • the corresponding signal of the branch branch arriving at the same state shall belong to the same subset ⁇ after the first level set. Or ⁇ ⁇ , which guarantees that the distance between different branches reaching the same state is greater than or equal to ⁇ .
  • the parallel path corresponds to the subset after the segmentation. This will ensure that the distance between parallel paths is greater than or equal to ⁇ TM .
  • the code rate and modulation method are: 1/2 16QAM, 3/4 16QAM, 2/3 64QAM, 5/6 64QAM , 3/4 256QAM, 7/8 256QAM.
  • the convolutional encoder used in the TCM code under Wimax SCa is a (2, 1, 7) binary convolutional code generator with a code rate of 1/2 and a beam length of 7. Its structure is shown in Figure 3.
  • the 5/6 64QAM, 7/8 256QAM TCM code needs to be punctured after the convolutional encoder with a code rate of 1/2, that is, a part of the encoded bit is deleted, and the code rate is changed to 3/4.
  • the punch pattern is X1Y1Y2X3, that is, every 3 groups of coded bits are punched, the first group is not punched, the second group is knocked off X, and the third group is knocked off Y.
  • a raw bit field of length 2 uluO enters the TCM encoder, and the TCM encoder part uses a convolutional code of 1/2.
  • the input order of uluO is ul is the first arrival bit, and uO is the backward arrival bit.
  • Ul is a pass-through bit
  • uO is 1/2 convolutional coding for entering the convolutional encoder bit
  • a set of 3-bit constellation index b5b4b3 is obtained, which is mapped to the I path, which is related to the coordinates of the I path, where b4b3 is the encoded bit group.
  • b5 is an uncoded bit group.
  • Another set of original bit information group uluO is input to the encoder to obtain another set of 3-bit constellation index b2blb0, which is mapped to the Q path, which is related to the coordinates of the Q path, where blbO is the encoded bit group and b2 is the uncoded bit. group. Since it produces a 6-bit output every 4 input bits, the encoder should be called an encoder with a code rate of 4/6.
  • signal points are determined in the existing 64QAM constellation map and used as the final transmitted TCM signal.
  • the existing 64QAM constellation map is shown in Figure 5.
  • the signal points of the same group of the I-coded bit group b4b3 and the Q-channel coded bit group blbO are the same subset, for example, the I channel and the Q channel are (110, 001), (010, 001), (110, respectively)
  • the signal points of 101, (010, 101) are the same subset, wherein the bit group b4b3 after the I channel coding is 10, and the bit group blbO is 01 after the Q channel coding, and the I channel and the Q channel are respectively (110,
  • the signal points of 011), (010, 011), (110, 111), (010, 111) are the same subset, wherein the bit group b4b3 after the I channel coding is 10, and the bit group blbO after the Q channel coding is 11, through It is not difficult to find these two subsets that the TCM coded output signal points (the TCM coded output signal points on the parallel path, that is, the signal points in the same subset) on the two parallel
  • the Euclidean distance of the symbols (that is, the signal points in the same subset) is also long and short.
  • the I and Q paths are a subset of the signal points of (110, 001), (010, 001), (110, 101), and (010, 101), respectively, and the Euclidean distance is compared with the I and Q paths respectively (
  • the Euclidean distance of the subset of signal points of 110, 011), (010, 011), (110, 111), (010, 111) is short. 5/6 64QAM TCM encoder structure diagram shown in Figure 6.
  • a raw bit information group u4u3u2ulu0 of length 5 enters the TCM encoder, and the TCM encoder part uses a convolutional code with a code rate of 3/4 (the original 1/2 convolutional code is punctured to make the code rate become 3/4) .
  • the input order of u4u3u2ulu0 is u4, u3, u2, ul, u0.
  • U2ulu0 performs 3/4 convolutional coding, and the output is c3c2clc0.
  • the uncoded bit u4 and the encoded bit c3c2 are combined into a set of 3-bit constellation index b5b4b3, which is mapped to the I path, where b4b3 is the encoded bit group and b5 is the uncoded bit group.
  • U3clc0 is a set of 3-bit constellation index b2blb0, mapped to the Q path, where blbO is the encoded bit group and b2 is the uncoded bit group.
  • the signal point is determined in the existing 64QAM constellation map and used as the final transmitted TCM signal.
  • the existing 64QAM constellation map is shown in Figure 5.
  • a raw bit block u2ulu0 of length 3 enters the TCM encoder, and the TCM encoder section uses a convolutional code of 1/2.
  • the input order of u2ulu0 is: u2, ul, u0.
  • U2ul is a pass-through bit
  • u0 performs 1/2 convolutional coding
  • a set of 4-bit constellation index b7b6b5b4 is obtained, which is mapped to the I path, which is related to the coordinates of the I path, where b5b4 is the encoded bit group, and b7b6 is the uncoded bit group. .
  • a set of original bit information groups u2ulu0 is input to the encoder, and another set of 4-bit constellation index b3b2blb0 is generated, which is mapped to the Q path, which is related to the coordinates of the Q path, where blbO is the encoded bit group, and b3b2 is the uncoded bit. group. Since it produces an 8-bit output for every 6 input bits, the encoder should be called an encoder with a 6/8 bit rate.
  • the signal point is determined in the existing 256QAM constellation map and used as the final transmitted TCM signal.
  • the current 256QAM constellation map is shown in Figure 8.
  • the TCM encoder section uses a convolutional code with a code rate of 3/4 (the original 1/2 convolutional code is punctured to make the code rate 3/4).
  • the input order of u6u5u4u3u2ulu0 is u6, u5, u4, u3, u2, ul, u0.
  • U2ulu0 performs 3/4 convolutional coding, and the output is c3c2clc0.
  • the uncoded bit group u6u5 and the encoded bit group c3c2 are combined into a set of 4-bit constellation index b7b6b5b4, which is mapped to the I path, where b5b4 is the encoded bit group and b7b6 is the uncoded bit group.
  • U4u3clc0 is combined into a set of 4-bit constellation index b3b2blb0, which is mapped to the Q path, where blbO is the encoded bit group and b3b2 is the uncoded bit group.
  • the signal point is determined in the existing 256QAM constellation map and used as the final transmitted TCM signal.
  • the current 256QAM constellation map is shown in Figure 8.
  • the decoding process of the TCM code can be roughly divided into the following two steps: subset decoding; soft decision Viterbi decoding.
  • a soft decision metric is obtained for 2 TM coded bit groups, and the metric value is usually a subset decoded signal point corresponding to each coded bit group (the subset and the received symbol) The Euclidean distance of the signal point with the smallest Euclidean distance or its linear transformation. Substituting the above soft decision metric into the Viterbi decoder for decoding operation, an estimated value (decoding result) of the original bit block can be obtained.
  • a defect of the prior art TCM codes with modulation orders greater than 4 is that their coding and modulation are based on existing
  • the constellation map determines the signal point, determines the final transmitted TCM signal, and the TCM coded output signal points (that is, the signal points in the same subset) on each parallel path are not uniformly mapped on the Q path, which makes the Q path have children.
  • the Euclidean distance of the set is long, the Euclidean distance of some subsets is short, and the shortest is the adjacent constellation. The distance between the points, as shown in FIG.
  • the encoded bit groups of the four signal points marked are the same, and are the signal points in the same subset, and the distance of the Q path of the signal points in the subset is 1 ( The Euclidean distance between adjacent signal points in the constellation map is 1).
  • the distance of the Q path of the signal points in the subset is 7.
  • the subset of the Q-path has a long Euclidean distance, and some of the subsets have a short Euclidean distance, which deteriorates the overall performance of the TCM code.
  • the decoding process is decoded according to the existing constellation diagram.
  • a coding and modulation method for a TCM including:
  • a signal point is determined in the constellation map as a final transmitted TCM signal based on the constellation index.
  • the embodiment of the invention further provides a method for decoding a trellis coded modulation code (TCM), which includes:
  • the example also provides a code modulation device for a TCM, including:
  • a storage module configured to store a quadrature amplitude modulation QAM constellation with a modulation order greater than 4 as a constellation map of the TCM, and map the encoded bit groups on the constellation map I and Q on the I path and Q Repeatedly arranged on the road, respectively, and the uncoded bit groups corresponding to the coded bit groups repeatedly arranged in each cycle are different from each other;
  • a constellation index obtaining module configured to obtain a constellation index including the encoded bit group and the uncoded bit group according to the original bit information group;
  • the TCM signal confirmation module is configured to determine a signal point in the constellation map as a final transmitted TCM signal according to the constellation index.
  • the embodiment of the invention further provides a decoding device for a trellis coded modulation code (TCM), which comprises:
  • a storage module configured to store a quadrature amplitude modulation QAM constellation with a modulation order greater than 4 as a constellation map of the TCM, and map the encoded bit groups on the constellation map I and Q on the I path and Q Repeatedly arranged on the road, respectively, and the uncoded bit groups corresponding to the coded bit groups repeatedly arranged in each cycle are different from each other;
  • Decoding module configured to perform decoding processing on the signal to be decoded according to the constellation map. It can be seen from the specific implementation provided by the above invention that it is precisely because the post-encoding bit group period is repeatedly arranged and the corresponding uncoded bit groups are different from each other, so that the symbols of the parallel path are uniformly mapped on the constellation map, so that the TCM code is Overall performance has improved.
  • DRAWINGS 1 is a schematic diagram of a prior art TCM code modulation structure
  • FIG. 2 is a schematic diagram of a 16QAM set partitioning in the prior art
  • FIG. 3 is a schematic diagram showing the structure of a prior art code rate 1/2 convolutional encoder
  • FIG. 4 is a schematic structural diagram of a prior art 2/3 64QAM TCM encoder
  • FIG. 6 is a schematic structural diagram of a prior art 5/6 64QAM TCM encoder
  • FIG. 7 is a schematic structural diagram of a prior art 3/4 256QAM TCM encoder
  • FIG. 9 is a schematic structural diagram of a prior art 7/8 256QAM TCM encoder
  • 10A is a schematic diagram of a prior art parallel path distance
  • 10B is a schematic diagram of a prior art parallel path distance
  • FIG. 11 is a flowchart of a method according to a first embodiment of the present invention.
  • FIG. 12A is a 64QAM constellation map of a TCM according to a first embodiment of the present invention
  • FIG. 12B is a 64QAM constellation map of a TCM according to a first embodiment of the present invention
  • FIG. 12C is a 64QAM of a TCM according to a first embodiment of the present invention
  • FIG. 13A is a 256QAM constellation map of a TCM according to a first embodiment of the present invention
  • FIG. 13B is a 256QAM constellation map of a TCM according to a first embodiment of the present invention
  • FIG. 14 is a second embodiment of the present invention.
  • 15 is a schematic diagram of comparison of 2/3 64QAM TCM code BER simulation results according to an embodiment of the present invention.
  • 16 is a schematic diagram of comparison of 5/6 64QAM TCM code BER simulation results according to an embodiment of the present invention
  • FIG. 17 is a schematic diagram showing comparison of BER simulation results of 3/4 256QAM TCM codes according to an embodiment of the present invention.
  • FIG. 18 is a comparison of BER simulation results of 7/8 256QAM TCM codes according to an embodiment of the present invention.
  • FIG. 19 is a schematic structural diagram of a device according to a third embodiment of the present invention.
  • FIG. 20 is a schematic structural diagram of a device according to a fourth embodiment of the present invention. detailed description
  • the preferred modulation mapping method of the TCM coding structure of 2/3 64QAM, 5/6 64QAM, 3/4 256QAM, 7/8 256QAM proposed by the embodiment of the present invention is not only a kind of only one kind, but a certain mapping rule is satisfied.
  • a collection of modulation mapping methods. This mapping rule is described below.
  • the number of bits of the encoded bit group of the TCM code is four (the encoded bit group refers to one or more output bits after convolutional coding), and is mapped to the I and Q paths on the constellation, respectively.
  • Each channel maps 2 bits.
  • the modulation order be M
  • the number of bits of the uncoded bit group is (M-4)
  • the number of bits mapped on each path of I/Q is (M-4)/2
  • uncoded bit group refers to Is a pass-through bit, one or more output bits that are not convolutionally encoded).
  • the sequence of coded bit groups mapped on each I/Q of the path needs to satisfy the characteristics of periodic repetition.
  • the corresponding uncoded bit groups need to be different.
  • the order of uncoded bit groups has no special requirements.
  • the encoded bit group sequence mapped in the I path and the Q path needs to satisfy the Gray code mapping rule respectively, that is, only one bit between the two adjacent coded bit groups in the sequence is different.
  • the coding and modulation method of the trellis coded modulation code that satisfies the above mapping rule provided by the embodiment of the present invention includes: Establishing a QAM constellation diagram with a modulation order greater than 4 as a constellation map of the trellis coded modulation code, so that the coded bit groups mapped on the constellation map I and Q are periodically repeated on the I and Q paths, respectively. Arranging, and making uncoded bit groups corresponding to the coded bit groups repeatedly arranged in each cycle different from each other; obtaining a constellation index including the encoded bit group and the uncoded bit group according to the original bit information group; The signal point is determined in the constellation map as the finally transmitted trellis coded modulation code signal.
  • the first embodiment provided by the present invention is a coding and modulation method of a trellis coded modulation code (TCM).
  • TCM trellis coded modulation code
  • Step 101 Establish a constellation map of the 5/6 64QAM TCM as shown in FIG. 12A.
  • the four bits of the encoded bit group in the constellation map are respectively mapped to the combination of b4b3 of the I path and blbO, b4b3 or blbO of the Q path.
  • There are 2 2 4 in total, so the period of the bit sequence repetition after encoding on each road is 4.
  • the two uncoded bits are mapped to b5 of the I path and b2 of the Q path, respectively.
  • the value of b5 needs to be different.
  • the value of b2 needs to be different.
  • the preferred mapping method therein is as follows.
  • I/Q path coordinate value 7A 5A 3A A -A -3A -5A -7A (A is the constellation diagram power normalization factor)
  • I road b5 0 0 0 0 1 1 1 1 (may also be 0 1 1
  • Step 102 Receive a raw bit information group "10011" (corresponding respectively
  • U4u3u2ulu0 Enter the 5/664QAM TCM encoder.
  • the input order of "1001 ⁇ is the first "1" first arrival, the first "0" second arrival, the second "0" third arrival, the second "1” fourth arrival The third "1" finally arrived.
  • Step 103 The TCM encoder encodes the original bit information group "10011" to obtain a constellation index including the encoded bit group and the uncoded bit group.
  • the TCM encoder section uses a convolutional code with a code rate of 3/4 (the original 1/2 convolutional code is punctured to make the code rate 3/4). For "01 ⁇ 3/4 convolutional coding, if the initial value of the six registers of the convolutional encoder is 0, the output is "111 0" (corresponding to c3c2clc0 respectively), and the order is the first “1” first. Output, second "1" second, third "1" third, "0" last.
  • Uncoded bit group "1" (u4) combined with encoded bit group "11" (c3c2) The 3-bit constellation index "ill” (b5b4b3) is mapped to the I path, where the last two “1”s (b4b3) are the encoded bit groups, and the first "1” (b5) is the uncoded bit group.
  • "(u3clc0) is a set of 3-bit constellation index "010" (b2blb0) mapped to the Q path, where the last two bits “10" (blbO) are the encoded bit group, the first "0" (b2) ) is an uncoded bit group.
  • Step 104 According to the obtained I-way constellation index "111" and the Q-way constellation index "010", the constellation map of the 5/664QAM TCM is established in step 101 (as shown in FIG. 12A), and the I-way coordinate is determined to be -7.
  • the Q path coordinates are 3 signal points and the signal point is used as the final transmitted TCM signal.
  • the constellation map of 5/664QAM TCM can also be obtained as shown in FIG. 12B and FIG. 12C, which indicates that the constellation map of 5/664QAMTCM is not unique, but satisfies the foregoing description.
  • 3/4256QAM, 7/8 can also be obtained.
  • the constellation map of 256QAM, and determine the final transmitted TCM signal, will not be described here.
  • the constellation map in the preferred scheme of 256QAM is shown in FIG. 13A, and the constellation map of the same 256QAM is not the only one shown in FIG. 13A, and can also be as shown in FIG. 13B, which satisfies the technical principle described above. set.
  • the technical solution described in the embodiments of the present invention makes signal points in the same subset on the constellation map, especially on the Q road, and the minimum Euclidean distance of the signal points in the same subset is greater than 4 in the prior art.
  • a second embodiment of the present invention provides a trellis coded modulation code (TCM) decoding method, which is exemplified by a 5/6 64QAM TCM code, and includes:
  • Step 201 Establish a constellation map of the 5/6 64QAM TCM. As shown in FIG. 12A, the specific scheme is the same as step 101.
  • the decoding signal is subjected to subsequent decoding processing by using the prior art.
  • decoding processing scheme subset decoding and soft decision Viterbi decoding may be employed.
  • Step 202 Sub-set decoding, in the four signal points of each subset of the 16 subsets of the constellation map of Fig. 12A, find the signal point with the smallest Euclidean distance from the received symbol.
  • the schematic diagram of determining the signal point with the smallest Euclidean distance during decoding is shown in Fig. 14.
  • the circle is the position of the received signal point, and the subset corresponding to the bit group "0000" (b4b3blb0) after encoding is the four signals in Fig. 14. Point, then the upper left signal point is the subset decoding result.
  • Step 203 Soft-decision Viterbi decoding, in the result of the subset decoding, obtains the Euclidean distance of the 16 encoded bit groups as its soft decision metric. By substituting the soft decision metric value into the Viterbi decoder for decoding operation, an estimated value (decoding result) for the original bit block can be obtained.
  • the technical principle of the decoding process of 2/3 64QAM, 3/4 256QAM, 7/8 256QAMTCM code is the same as that of the 5/6 64QAM TCM code described above, and will not be described here.
  • the decoding process is performed according to the constellation diagram provided by the embodiment of the present invention, so that the signal points in the same subset are uniformly mapped on the constellation map, especially on the Q road, and the minimum Euclidean distance of the signal points in the same subset is 4 is larger than the minimum Euclidean distance 1 in the prior art, and the minimum Euclidean distance of the TCM coded output signal point on the parallel path is larger than the minimum Euclidean distance of the prior art, and the decoding error occurs under a certain signal to noise ratio.
  • the probability is less than the probability of decoding errors in the prior art, and the overall performance of the TCM code is improved.
  • the TCM code described in the embodiment of the present invention can be applied to the TCM code under Wimax SCa as an improved solution. It is also applicable to other communication systems that use such TCM codes.
  • BER bit error rate simulation results of 2/3 64QAM, 5/6 64QAM, 3/4 256QAM, 7/8 256QAM TCM codes defined in the prior art and preferred TCM codes described in the embodiments of the present invention
  • the comparison is shown in Fig. 15, Fig. 16, Fig. 17, and Fig. 18.
  • Wimax represents the TCM code defined in the Wimax protocol
  • MY represents the preferred TCM code described in the embodiment of the present invention
  • the channel is the AWGN channel
  • Es/Nt is the ratio of the symbol energy to the noise power in the unit bandwidth, that is, normalized. Signal to noise ratio.
  • the performance of the preferred TCM code described in the embodiments of the present invention is significantly improved by the 256QAM, 7/8 256QAM TCM code.
  • the TCM code designed by the embodiment of the present invention can maintain the definition of the original Wimax protocol.
  • the coding part of the TCM code has the same structure, and only needs to change the constellation map to obtain significant gain, which is compatible with the original protocol.
  • the third embodiment of the present invention is a code modulation device of a TCM, and its structure is as shown in FIG. 19, including:
  • the storage module 301 is configured to store a square QAM constellation diagram with a modulation order greater than 4 as
  • a constellation map of the TCM mapping the encoded bits on the I and Q paths of the constellation map
  • the groups are repeatedly arranged periodically on the I path and the Q path, and the uncoded bit groups corresponding to the coded bit groups repeatedly arranged in each cycle are different from each other;
  • a constellation index obtaining module 302 configured to obtain, according to the original bit information group, a constellation index including the encoded bit group and the uncoded bit group;
  • the TCM signal confirmation module 303 is configured to determine a signal point in the constellation map according to the constellation index as a final transmitted TCM signal.
  • the fourth embodiment of the present invention provides a trellis coded modulation code (TCM) decoding device, and the structure thereof is as shown in FIG. 20, including:
  • the storage module 401 is configured to store a square QAM constellation diagram with a modulation order greater than 4 as a constellation map of the TCM, and the coded bit groups mapped on the constellation map I and Q paths are respectively on the I road and the Q road.
  • the cycle is repeatedly arranged, and the uncoded bit groups corresponding to the coded bit groups repeatedly arranged in each cycle are different from each other;
  • the decoding module 402 is configured to perform decoding processing on the signal to be decoded according to the constellation map. Specifically, in practical applications, the constellation diagram used in this embodiment can be combined with the present invention.

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Abstract

Encoding modulation method, decoding method and apparatus of trellis coded modulation code are disclosed. The encoding method comprises steps of establishing a QAM constellation picture which is TCM constellation map picture with modulation level exceeding 4; making encoded bit groups of the constellation picture with I route and Q route to be arranged periodically and repeatedly in the I route and Q route; making un-encoded bit groups which correspond to encoded bit groups with period repeat arrangement to be different from each other; obtaining constellation index including the encoded and un-encoded bit groups according to the original bit information groups; determining a signal point as finally transmitted TCM signal in the constellation map. The symbols of parallel route are mapped evenly on the Q route of the constellation map because the encoded bit groups are arranged periodically and repeatedly, thus the performance of TCM code is improved.

Description

一种网格编码调制码的编码调制、 译码方法及装置 技术领域  Coded modulation, decoding method and device for trellis coded modulation code
本发明属于数据编码技术领域, 特别涉及一种网格编码调制码的编码调 制、 译码方法及装置。 背景技术  The invention belongs to the technical field of data coding, and in particular relates to a code modulation and decoding method and device for a trellis coded modulation code. Background technique
TCM ( trellis coded modulation网格编码调制 ) 编码, 即网格编码调 制技术, 是一种 "信号集空间编码" , 它能够在不降低频带利用率和功率 利用率的基础上, 将编码与调制相结合, 利用信号集的冗余度来获取纠错 能力。  TCM (Trellis coded modulation) coding, or trellis coded modulation technology, is a "signal set space coding" that can encode and modulate without reducing the band utilization and power utilization. Combined, the redundancy of the signal set is used to obtain error correction capability.
TCM码具有两个基本特征:  The TCM code has two basic characteristics:
1、 星座图中所用的信号点数大于不进行编码同种调制所需的点数, 这些附加的信号点为纠错编码提供冗余度。  1. The number of signal points used in the constellation diagram is greater than the number of points required to encode the same type of modulation. These additional signal points provide redundancy for error correction coding.
2、 采用卷积码在相继的信号点之间引入某种依赖性, 因而只有某些 信号点序列才是允许出现的, 这些允许的信号序列可以模型化为网格结 构, 因而称为网格编码调制。  2. Using a convolutional code to introduce a dependency between successive signal points, so only certain signal point sequences are allowed. These allowed signal sequences can be modeled as a grid structure, hence the name grid. Code modulation.
TCM的基本思想是: 采用扩展信号集来提供可控的编码冗余, 对卷 积编码和多元调制映射进行统一设计, 即对传输信号点集进行集合分割映 射以使编码信号序列之间的自由欧氏距离(平方欧氏距离为两信号点间距 离的平方, 筒称欧氏距离, 自由欧氏距离定义为从零时刻同一状态开始分 叉、 而在后续某时刻某状态有交汇的两个无限长信号点序列之间的最小欧 氏距离。 ) 达到最大。  The basic idea of TCM is to use an extended signal set to provide controllable coding redundancy, and to design convolutional coding and multi-modulation mapping uniformly, that is, to perform hierarchical segmentation mapping on the transmitted signal point set to make the coded signal sequence free. Euclidean distance (the squared Euclidean distance is the square of the distance between two signal points, the cylinder is called the Euclidean distance, the free Euclidean distance is defined as the bifurcation from the same state at zero time, and the two at the subsequent time have a convergence The minimum Euclidean distance between sequences of infinitely long signal points.) Maximizes.
如图 1所示, TCM信号是通过如下方式产生的: 在一时刻 n, —长度 为 k的原始比特信息组进入编码器,其中的 个进入卷积编码器比特( ≤ k ) 通过一个码率为 的卷积编码器扩展成 ^个编码后比特组成的编码后比 特组,这 m个编码后比特用来选择 2k+m-k进制调制信号集的 个子集中的其 中一个子集, 剩下的 个直通比特组成未编码比特组, 用来在该子集中 的 1"个信号点中选择其中一个信号点作为最终发射的 TCM信号。 当 k 时, TCM码的网格图中将会出现 2"条平行转移分支 (转移分支对应的 起始与终止状态为同一个, 通常称为 2^条并行路径) , 这将导致单个错 误事件( Single Error Event )的发生(与多重错误事件 Multiple Error Event 相对应) 。 同一子集里的信号点对应着一束并行路径上的 TCM编码输出 信号点, 也就是说星座映射图上 ^个编码后比特均相同的 2"个信号点对 应着一束 条并行路径上的 TCM编码输出信号点。 As shown in Figure 1, the TCM signal is generated as follows: At a time n, the original bit block of length k enters the encoder, and one of them enters the convolutional encoder bit (≤ k) through a code rate. The convolutional encoder is expanded into a coded ratio of the encoded bits. Special group, the m coded bits are used to select one of the subsets of the 2 k+m - k modulation signal set, and the remaining pass bits form an uncoded bit group for use in the subset Select one of the 1" signal points as the final transmitted TCM signal. When k, 2 "parallel branch branches will appear in the grid map of the TCM code (the start and end states of the branch branch are The same, commonly referred to as 2 ^ parallel paths), which causes a single Error Event to occur (corresponding to the Multiple Error Event). The signal points in the same subset correspond to the TCM coded output signal points on a parallel path, that is, the 2 "signal points on the constellation map that are identical in coding are corresponding to a bundle of parallel paths. The TCM encodes the output signal point.
而上述子集的划分原理 (也叫集分割原理) , 在 TCM方案的构造中 具有十分重要的意义。 所谓集分割就是将一个信号集接连地分割成较小的 子集, 并使分割后的子集内的最小欧氏距离最大化。  The division principle of the above subset (also called the set division principle) is of great significance in the construction of the TCM scheme. The so-called set segmentation is to divide a signal set into smaller subsets one after another, and to maximize the minimum Euclidean distance in the segmented subset.
集分割原理应遵循如下两个原则:  The principle of set partitioning should follow the following two principles:
1、 在同级子集中, 每个子集所包含的信号点数及其欧氏距离分布均 应保持一致;  1. In the same level subset, the number of signal points and the Euclidean distance distribution contained in each subset should be consistent;
2、 随着子集的分割, 在较小的子集中, 信号点之间的最小欧氏距离 应逐级增大。 在设计 TCM方案时, 将具有 2 "^个信号点的调制信号集^ 作 m级分割。设经过第 i级分割后的子集 Ω,内最小欧氏距离为 Δ'· (^ 0'1'"'' m)2. With the division of the subset, in the smaller subset, the minimum Euclidean distance between the signal points should increase step by step. When designing the TCM scheme, the modulation signal set with 2 "^ signal points is divided into m stages. Let the subset Ω after the i-th stage division, the inner minimum Euclidean distance is Δ '· (^ 0 ' 1 '"'' m )
(当 = 时, 第 级子集中仅包含一个信号点, 此时令 Δ=∞ ) , 则有 W i'-^ 。 (When =, the first subset contains only one signal point, and at this time Δ TM = ∞ ), then there is W i'-^ .
级子集划分完成后, 同一子集里面的信号点对应的 ^个编码后比特 组即 . . . 3 是一样的 (也可以说, 个编码后比特组一样的信号点对应于 同一个子集) , 而为了区分开同一子集里面的 2"个信号点, 每个信号点 对应的 - 个未编码比特组须不一样。 对应于星座映射图, 个编码后比 特组均相同的 1"个信号点是属于同一个子集的,其对应的 - 个未编码比 特组必定是不一样的。 星座映射图上, 所有子集需符合集分割原理的。 After the division of the subset of stages is completed, the number of encoded bits corresponding to the signal points in the same subset is . . . 3 is the same (it can be said that the same signal points corresponding to the bit groups after encoding correspond to the same subset ), and in order to distinguish 2 "signal points in the same subset, the corresponding uncoded bit groups of each signal point must be different. Corresponding to the constellation map, the coding ratio The 1" signal points of the same group belong to the same subset, and the corresponding - uncoded bit groups must be different. On the constellation map, all subsets need to conform to the set partitioning principle.
图 2为 16QAM ( quadrature amplitude modulation正交幅度调制 )信 号点集的集合分割示意图。  2 is a schematic diagram of a set division of a 16QAM (quarature amplitude modulation) signal point set.
TCM最优码的网格图应遵循以下基本构造原则:  The grid diagram of the TCM optimal code should follow the following basic construction principles:
1、 所有的调制信号应有相同的出现频率, 并应有尽可能多的规则性和对 称性。 这一原则表明一个好的 TCM码应具有规则的结构, 这是因为 TCM方案 实际上是一种对信号空间作最佳分割的方案, 而调制信号空间是对称的, 所 以最佳分割方案也应具有规则性和对称性。  1. All modulated signals should have the same frequency of occurrence and should have as much regularity and symmetry as possible. This principle indicates that a good TCM code should have a regular structure. This is because the TCM scheme is actually a scheme for optimal segmentation of the signal space, and the modulation signal space is symmetric, so the optimal segmentation scheme should also Regular and symmetrical.
2、始于同一状态的转移分支的对应信号应属于同一个经第一级集分割后 的子集 β。或 βι , 这保证从同一状态分离的不同分支间距离大于或等于 Δι。 2. The corresponding signal of the branching branch starting from the same state shall belong to the same subset β after the first level set. Or β ι , which guarantees that the distance between different branches separated from the same state is greater than or equal to Δ ι.
3、到达同一状态的转移分支的对应信号应属于同一个经第一级集分割后 的子集 β。或 βι , 这保证到达同一状态的不同分支间距离大于或等于^。 3. The corresponding signal of the branch branch arriving at the same state shall belong to the same subset β after the first level set. Or β ι , which guarantees that the distance between different branches reaching the same state is greater than or equal to ^.
4、 并行路径对应于经 ^级集分割后的子集。 这将保证并行路径间的 距离大于或等于 Δ™。 4. The parallel path corresponds to the subset after the segmentation. This will ensure that the distance between parallel paths is greater than or equal to Δ TM .
对于全球微波接入互操作性增强的单载波(Wimax SCa )调制方式下 的 TCM码, 其码率与调制方式有: 1/2 16QAM、 3/4 16QAM、 2/3 64QAM、 5/6 64QAM, 3/4 256QAM, 7/8 256QAM。  For the TCM code in the single-carrier (Wimax SCa) modulation mode with enhanced global microwave access interoperability, the code rate and modulation method are: 1/2 16QAM, 3/4 16QAM, 2/3 64QAM, 5/6 64QAM , 3/4 256QAM, 7/8 256QAM.
Wimax SCa下的 TCM码中所用到的卷积编码器为一个码率为 1/2、约 束长度为 7的 (2,1,7)二进制卷积码发生器。 其结构如图 3所示。  The convolutional encoder used in the TCM code under Wimax SCa is a (2, 1, 7) binary convolutional code generator with a code rate of 1/2 and a beam length of 7. Its structure is shown in Figure 3.
5/6 64QAM、 7/8 256QAM的 TCM码需要在码率为 1/2的卷积编码器 后面进行打孔, 即把一部分编码后比特删除, 使其码率变为 3/4。 其打孔 图样为 X1Y1Y2X3 , 即每 3组编码后比特进行打孔, 第一组无打孔, 第二 组打掉 X, 第三组打掉 Y。  The 5/6 64QAM, 7/8 256QAM TCM code needs to be punctured after the convolutional encoder with a code rate of 1/2, that is, a part of the encoded bit is deleted, and the code rate is changed to 3/4. The punch pattern is X1Y1Y2X3, that is, every 3 groups of coded bits are punched, the first group is not punched, the second group is knocked off X, and the third group is knocked off Y.
其中对于 2/3 64QAM、 5/6 64QAM, 3/4 256QAM, 7/8 256QAM 的 T C M码的编码与调制过程如下所述。 Which for 2/3 64QAM, 5/6 64QAM, 3/4 256QAM, 7/8 256QAM The encoding and modulation process of the TCM code is as follows.
2/3 64QAM TCM编码器结构示意图如图 4所示。  2/3 64QAM TCM encoder structure diagram shown in Figure 4.
一长度为 2的原始比特信息组 uluO进入 TCM编码器, TCM编码器 部分使用码率为 1/2的卷积码。 uluO的输入顺序为 ul为先到达比特, uO 为后到达比特。 ul为直通比特, uO为进入卷积编码器比特进行 1/2卷积编 码, 得到一组 3比特的星座索引 b5b4b3 , 映射到 I路, 与 I路的坐标相关, 其中 b4b3为编码后比特组, b5为未编码比特组。 接着再有一组原始比特 信息组 uluO输入到编码器, 得到另外一组 3比特的星座索引 b2blb0, 映 射到 Q路, 与 Q路的坐标相关, 其中 blbO为编码后比特组, b2为未编码 比特组。 因为它是每 4个输入比特产生 6比特的输出, 所以该编码器应该 被称作码率为 4/6的编码器。  A raw bit field of length 2 uluO enters the TCM encoder, and the TCM encoder part uses a convolutional code of 1/2. The input order of uluO is ul is the first arrival bit, and uO is the backward arrival bit. Ul is a pass-through bit, uO is 1/2 convolutional coding for entering the convolutional encoder bit, and a set of 3-bit constellation index b5b4b3 is obtained, which is mapped to the I path, which is related to the coordinates of the I path, where b4b3 is the encoded bit group. , b5 is an uncoded bit group. Then another set of original bit information group uluO is input to the encoder to obtain another set of 3-bit constellation index b2blb0, which is mapped to the Q path, which is related to the coordinates of the Q path, where blbO is the encoded bit group and b2 is the uncoded bit. group. Since it produces a 6-bit output every 4 input bits, the encoder should be called an encoder with a code rate of 4/6.
根据得到的 I路星座索引 b5b4b3和 Q路星座索引 b2blb0, 在现有 64QAM星座映射图中确定信号点, 并作为最终发射的 TCM信号。 现有 64QAM星座映射图如图 5所示。其中 I路编码后比特组 b4b3相同和 Q路 编码后比特组 blbO相同的构成的信号点为同一子集, 如 I路和 Q路分别 为 (110, 001 ) 、 (010, 001 ) 、 ( 110, 101 ) 、 (010, 101 ) 的信号点 为同一子集, 其中 I路编码后比特组 b4b3为 10, Q路编码后比特组 blbO 为 01 , 又如 I路和 Q路分别为( 110, 011 )、 (010, 011 )、 ( 110, 111 )、 ( 010, 111 )的信号点为同一子集, 其中 I路编码后比特组 b4b3为 10, Q 路编码后比特组 blbO为 11 , 通过这两个子集不难发现, 这两个并行路径 上的 TCM编码输出信号点(并行路径上的 TCM编码输出信号点也即同一 子集里的信号点)在 Q路上的映射并不均匀, 这使得符号(也即同一子集 里的信号点) 的欧氏距离也有长有短。 I路和 Q路分别为 (110, 001 ) 、 ( 010, 001 ) 、 ( 110, 101 ) 、 (010, 101 ) 的信号点的子集, 其欧氏距 离比 I路和 Q路分别为( 110, 011 )、 (010, 011 )、 ( 110, 111 )、 (010, 111 ) 的信号点的子集的欧氏距离短。 5/6 64QAM TCM编码器结构示意图如图 6所示。 Based on the obtained I-way constellation index b5b4b3 and the Q-way constellation index b2blb0, signal points are determined in the existing 64QAM constellation map and used as the final transmitted TCM signal. The existing 64QAM constellation map is shown in Figure 5. The signal points of the same group of the I-coded bit group b4b3 and the Q-channel coded bit group blbO are the same subset, for example, the I channel and the Q channel are (110, 001), (010, 001), (110, respectively) The signal points of 101, (010, 101) are the same subset, wherein the bit group b4b3 after the I channel coding is 10, and the bit group blbO is 01 after the Q channel coding, and the I channel and the Q channel are respectively (110, The signal points of 011), (010, 011), (110, 111), (010, 111) are the same subset, wherein the bit group b4b3 after the I channel coding is 10, and the bit group blbO after the Q channel coding is 11, through It is not difficult to find these two subsets that the TCM coded output signal points (the TCM coded output signal points on the parallel path, that is, the signal points in the same subset) on the two parallel paths are not uniformly mapped on the Q path. The Euclidean distance of the symbols (that is, the signal points in the same subset) is also long and short. The I and Q paths are a subset of the signal points of (110, 001), (010, 001), (110, 101), and (010, 101), respectively, and the Euclidean distance is compared with the I and Q paths respectively ( The Euclidean distance of the subset of signal points of 110, 011), (010, 011), (110, 111), (010, 111) is short. 5/6 64QAM TCM encoder structure diagram shown in Figure 6.
一长度为 5的原始比特信息组 u4u3u2ulu0进入 TCM编码器, TCM 编码器部分使用码率为 3/4的卷积码 (原 1/2卷积码经过打孔使码率变为 3/4)。 u4u3u2ulu0的输入顺序依次为 u4, u3 , u2, ul , u0。 u2ulu0进行 3/4的卷积编码, 输出依次为 c3c2clc0。 未编码比特 u4与编码后比特 c3c2 合为一组 3比特的星座索引 b5b4b3 , 映射到 I路, 其中 b4b3为编码后比 特组, b5为未编码比特组。 u3clc0合为一组 3比特的星座索引 b2blb0, 映射到 Q路, 其中 blbO为编码后比特组, b2为未编码比特组。  A raw bit information group u4u3u2ulu0 of length 5 enters the TCM encoder, and the TCM encoder part uses a convolutional code with a code rate of 3/4 (the original 1/2 convolutional code is punctured to make the code rate become 3/4) . The input order of u4u3u2ulu0 is u4, u3, u2, ul, u0. U2ulu0 performs 3/4 convolutional coding, and the output is c3c2clc0. The uncoded bit u4 and the encoded bit c3c2 are combined into a set of 3-bit constellation index b5b4b3, which is mapped to the I path, where b4b3 is the encoded bit group and b5 is the uncoded bit group. U3clc0 is a set of 3-bit constellation index b2blb0, mapped to the Q path, where blbO is the encoded bit group and b2 is the uncoded bit group.
根据得到的 I路星座索引 b5b4b3和 Q路星座索引 b2blb0, 在现有 64QAM星座映射图中确定信号点, 并作为最终发射的 TCM信号。 现有 64QAM星座映射图如图 5所示。  Based on the obtained I-channel constellation index b5b4b3 and the Q-way constellation index b2blb0, the signal point is determined in the existing 64QAM constellation map and used as the final transmitted TCM signal. The existing 64QAM constellation map is shown in Figure 5.
3/4 256QAM TCM编码器结构示意图如图 7所示。  The structure of the 3/4 256QAM TCM encoder is shown in Figure 7.
一长度为 3的原始比特信息组 u2ulu0进入 TCM编码器, TCM编码 器部分使用码率为 1/2的卷积码。 u2ulu0的输入顺序依次为: u2, ul , u0。 u2ul为直通比特, u0进行 1/2卷积编码, 得到一组 4比特的星座索引 b7b6b5b4, 映射到 I路, 与 I路的坐标相关, 其中 b5b4为编码后比特组, b7b6为未编码比特组。 接着再有一组原始比特信息组 u2ulu0输入到编码 器, 产生另外一组 4比特的星座索引 b3b2blb0, 映射到 Q路, 与 Q路的 坐标相关, 其中 blbO为编码后比特组, b3b2为未编码比特组。 因为它是 每 6个输入比特产生 8比特的输出, 所以该编码器应该被称作码率为 6/8 的编码器。  A raw bit block u2ulu0 of length 3 enters the TCM encoder, and the TCM encoder section uses a convolutional code of 1/2. The input order of u2ulu0 is: u2, ul, u0. U2ul is a pass-through bit, u0 performs 1/2 convolutional coding, and a set of 4-bit constellation index b7b6b5b4 is obtained, which is mapped to the I path, which is related to the coordinates of the I path, where b5b4 is the encoded bit group, and b7b6 is the uncoded bit group. . Then, a set of original bit information groups u2ulu0 is input to the encoder, and another set of 4-bit constellation index b3b2blb0 is generated, which is mapped to the Q path, which is related to the coordinates of the Q path, where blbO is the encoded bit group, and b3b2 is the uncoded bit. group. Since it produces an 8-bit output for every 6 input bits, the encoder should be called an encoder with a 6/8 bit rate.
根据得到的 I路星座索引 b7b6b5b4和 Q路星座索引 b3b2blb0, 在现 有 256QAM星座映射图中确定信号点, 并作为最终发射的 TCM信号。 现 有 256QAM星座映射图如图 8所示。  Based on the obtained I-channel constellation index b7b6b5b4 and the Q-way constellation index b3b2blb0, the signal point is determined in the existing 256QAM constellation map and used as the final transmitted TCM signal. The current 256QAM constellation map is shown in Figure 8.
7/8 256QAM TCM编码器结构示意图如图 9所示。  The structure of the 7/8 256QAM TCM encoder is shown in Figure 9.
一长度为 7的原始比特信息组 u6u5u4u3u2ulu0进入 TCM编码器, TCM编码器部分使用码率为 3/4的卷积码 (原 1/2卷积码经过打孔使码率变 为 3/4)。 u6u5u4u3u2ulu0的输入顺序依次为 u6 , u5 , u4 , u3 , u2 , ul , u0。u2ulu0进行 3/4的卷积编码,输出依次为 c3c2clc0。未编码比特组 u6u5 与编码后比特组 c3c2合为一组 4比特的星座索引 b7b6b5b4 , 映射到 I路, 其中 b5b4为编码后比特组, b7b6为未编码比特组。 u4u3clc0合为一组 4 比特的星座索引 b3b2blb0,映射到 Q路,其中 blbO为编码后比特组, b3b2 为未编码比特组。 A raw bit information group u6u5u4u3u2ulu0 of length 7 enters the TCM encoder. The TCM encoder section uses a convolutional code with a code rate of 3/4 (the original 1/2 convolutional code is punctured to make the code rate 3/4). The input order of u6u5u4u3u2ulu0 is u6, u5, u4, u3, u2, ul, u0. U2ulu0 performs 3/4 convolutional coding, and the output is c3c2clc0. The uncoded bit group u6u5 and the encoded bit group c3c2 are combined into a set of 4-bit constellation index b7b6b5b4, which is mapped to the I path, where b5b4 is the encoded bit group and b7b6 is the uncoded bit group. U4u3clc0 is combined into a set of 4-bit constellation index b3b2blb0, which is mapped to the Q path, where blbO is the encoded bit group and b3b2 is the uncoded bit group.
根据得到的 I路星座索引 b7b6b5b4和 Q路星座索引 b3b2blb0, 在现 有 256QAM星座映射图中确定信号点, 并作为最终发射的 TCM信号。 现 有 256QAM星座映射图如图 8所示。  Based on the obtained I-channel constellation index b7b6b5b4 and the Q-way constellation index b3b2blb0, the signal point is determined in the existing 256QAM constellation map and used as the final transmitted TCM signal. The current 256QAM constellation map is shown in Figure 8.
TCM码的译码过程大致可分为以下两个步骤: 子集译码 (sub set decoding); 软判决 Viterbi译码。  The decoding process of the TCM code can be roughly divided into the following two steps: subset decoding; soft decision Viterbi decoding.
1. 子集译码  Subset decoding
在星座映射图 2™个子集的每个子集的 2"个信号点中, 找出与接收信 号符号欧氏距离最小的信号点。 Among the 2 " signal points of each subset of the constellation map of Fig. 2, the signal point with the smallest Euclidean distance from the received signal symbol is found.
2. 软判决 Viterbi译码  2. Soft decision Viterbi decoding
在子集译码的结果中, 得到关于 2™个编码后比特组的软判决度量值, 度量值通常为每个编码后比特组所对应的子集译码信号点(该子集中与接 收符号欧氏距离最小的信号点)的欧氏距离或其线性变换。 将上述软判决 度量值代入 Viterbi译码器中进行译码操作, 即可得到对原始比特信息组 的估计值 (译码结果) 。 In the result of the subset decoding, a soft decision metric is obtained for 2 TM coded bit groups, and the metric value is usually a subset decoded signal point corresponding to each coded bit group (the subset and the received symbol) The Euclidean distance of the signal point with the smallest Euclidean distance or its linear transformation. Substituting the above soft decision metric into the Viterbi decoder for decoding operation, an estimated value (decoding result) of the original bit block can be obtained.
现有技术的调制阶数大于 4的 TCM码(如 2/3 64QAM、 5/6 64QAM、 3/4 256QAM、 7/8 256QAM 的 TCM码)一个的缺陷为它们的编码与调制根据现 有的星座图确定信号点, 确定最终发射的 TCM信号, 各并行路径上的 TCM编 码输出信号点 (也即同一子集里的信号点)在 Q路上的映射并不均匀, 这使 得 Q路上有的子集的欧氏距离长, 有的子集的欧氏距离短, 最短为相邻星座 点之间的距离, 如图 10A所示, 标注的四个信号点的编码后比特组均相同, 为同一个子集里的信号点, 其子集内信号点的 Q路的距离为 1 ( 支设星座映射 图中相邻信号点之间的欧氏距离为 1 ) 。 如图 10B所示星座映射图中另外一个 子集, 其子集内信号点的 Q路的距离为 7。 由图 10A和图 10B的对比可看出, 明 显 Q路上有的子集的欧氏距离长, 有的子集的欧氏距离短, 会使 TCM码的整 体性能变差。 译码过程根据现有的星座图进行译码, 对于并行路径上的 TCM 编码输出信号点的欧氏距离短的情况, 其译码出错的可能性大, 而且这也不 符合前面所描述的 TCM最优码构造原则中的调制信号应有尽可能多的规则性 和对称性。 发明内容 A defect of the prior art TCM codes with modulation orders greater than 4 (such as 2/3 64QAM, 5/6 64QAM, 3/4 256QAM, 7/8 256QAM TCM codes) is that their coding and modulation are based on existing The constellation map determines the signal point, determines the final transmitted TCM signal, and the TCM coded output signal points (that is, the signal points in the same subset) on each parallel path are not uniformly mapped on the Q path, which makes the Q path have children. The Euclidean distance of the set is long, the Euclidean distance of some subsets is short, and the shortest is the adjacent constellation. The distance between the points, as shown in FIG. 10A, the encoded bit groups of the four signal points marked are the same, and are the signal points in the same subset, and the distance of the Q path of the signal points in the subset is 1 ( The Euclidean distance between adjacent signal points in the constellation map is 1). As shown in another subset of the constellation map shown in FIG. 10B, the distance of the Q path of the signal points in the subset is 7. As can be seen from the comparison of Fig. 10A and Fig. 10B, it is apparent that the subset of the Q-path has a long Euclidean distance, and some of the subsets have a short Euclidean distance, which deteriorates the overall performance of the TCM code. The decoding process is decoded according to the existing constellation diagram. If the Euclidean distance of the TCM encoded output signal point on the parallel path is short, the decoding error is high, and this does not conform to the TCM described above. The modulation signal in the optimal code construction principle should have as much regularity and symmetry as possible. Summary of the invention
为了解决 Q路上有的子集的欧氏距离长, 有的子集的欧氏距离短, 最 短为相邻星座点之间的距离, 使得 TCM码的整体性能变差的问题, 本发 明实施例提供了一种 TCM的编码调制方法, 包括:  In order to solve the problem that the Euclidean distance of the subset on the Q-path is long, the Euclidean distance of some subsets is short, and the shortest distance is the distance between adjacent constellation points, so that the overall performance of the TCM code is deteriorated, the embodiment of the present invention A coding and modulation method for a TCM is provided, including:
建立调制阶数大于 4的正交幅度调制 QAM星座图作为 TCM的星座 映射图, 使映射在所述星座映射图 I路和 Q路上的编码后比特组在所述 I 路和 Q路上分别周期重复排列,且使与每一次周期重复排列的编码后比特 组对应的未编码比特组彼此不同;  Establishing a quadrature amplitude modulation QAM constellation with a modulation order greater than 4 as a constellation map of the TCM, so that the coded bit groups mapped on the constellation map I and Q are periodically repeated on the I and Q paths, respectively. Arranging, and making uncoded bit groups corresponding to the coded bit groups repeatedly arranged in each cycle different from each other;
根据原始比特信息组得到包括编码后比特组和未编码比特组的星座 索引;  Obtaining a constellation index including the encoded bit group and the uncoded bit group according to the original bit information group;
根据所述星座索引在所述星座映射图中确定信号点作为最终发射的 TCM信号。  A signal point is determined in the constellation map as a final transmitted TCM signal based on the constellation index.
本发明实施例还提供了一种网格编码调制码(TCM )的译码方法, 包 括:  The embodiment of the invention further provides a method for decoding a trellis coded modulation code (TCM), which includes:
建立调制阶数大于 4的正交幅度调制 QAM星座图作为 TCM的星座 映射图, 使映射在所述星座映射图 I路和 Q路上的编码后比特组在所述 I 路和 Q路上分别周期重复排列,且使与每一次周期重复排列的编码后比特 组对应的未编码比特组彼此不同; Establishing a quadrature amplitude modulation QAM constellation with a modulation order greater than 4 as a constellation map of the TCM, so that the coded bit groups mapped on the constellation map I and Q are in the I The path and the Q path are repeatedly arranged in a cycle, and the uncoded bit groups corresponding to the coded bit groups repeatedly arranged in each cycle are different from each other;
根据所述星座映射图对待译码信号进行译码处理。  Decoding the signal to be decoded according to the constellation map.
为了解决 Q路上有的子集的欧氏距离长, 有的子集的欧氏距离短, 最 短为相邻星座点之间的距离, 使得 TCM码的整体性能变差的问题, 同时 本发明实施例还提供一种 TCM的编码调制装置, 包括:  In order to solve the problem that the Euclidean distance of the subset on the Q-path is long, the Euclidean distance of some subsets is short, and the shortest distance is the distance between adjacent constellation points, so that the overall performance of the TCM code is deteriorated, and the present invention is implemented. The example also provides a code modulation device for a TCM, including:
存储模块: 用于存储调制阶数大于 4的正交幅度调制 QAM星座图作 为 TCM的星座映射图, 映射在所述星座映射图 I路和 Q路上的编码后比 特组在所述 I路和 Q路上分别周期重复排列, 与每一次周期重复排列的编 码后比特组对应的未编码比特组彼此不同;  a storage module: configured to store a quadrature amplitude modulation QAM constellation with a modulation order greater than 4 as a constellation map of the TCM, and map the encoded bit groups on the constellation map I and Q on the I path and Q Repeatedly arranged on the road, respectively, and the uncoded bit groups corresponding to the coded bit groups repeatedly arranged in each cycle are different from each other;
星座索引获取模块:用于根据原始比特信息组得到包括编码后比特组 和未编码比特组的星座索引;  a constellation index obtaining module: configured to obtain a constellation index including the encoded bit group and the uncoded bit group according to the original bit information group;
TCM信号确认模块: 用于根据所述星座索引在所述星座映射图中确 定信号点作为最终发射的 TCM信号。  The TCM signal confirmation module is configured to determine a signal point in the constellation map as a final transmitted TCM signal according to the constellation index.
本发明实施例还提供了一种网格编码调制码(TCM )的译码装置, 包 括:  The embodiment of the invention further provides a decoding device for a trellis coded modulation code (TCM), which comprises:
存储模块: 用于存储调制阶数大于 4的正交幅度调制 QAM星座图作 为 TCM的星座映射图, 映射在所述星座映射图 I路和 Q路上的编码后比 特组在所述 I路和 Q路上分别周期重复排列, 与每一次周期重复排列的编 码后比特组对应的未编码比特组彼此不同;  a storage module: configured to store a quadrature amplitude modulation QAM constellation with a modulation order greater than 4 as a constellation map of the TCM, and map the encoded bit groups on the constellation map I and Q on the I path and Q Repeatedly arranged on the road, respectively, and the uncoded bit groups corresponding to the coded bit groups repeatedly arranged in each cycle are different from each other;
译码模块: 用于根据所述星座映射图对待译码信号进行译码处理。 由上述本发明提供的具体实施方案可以看出, 正是由于编码后比特组周 期重复排列且对应的未编码比特组彼此不同, 使得并行路径的符号在星座映 射图上映射均匀, 使得 TCM码的整体性能得到提升。 附图说明 图 1为现有技术 TCM编码调制结构示意图; Decoding module: configured to perform decoding processing on the signal to be decoded according to the constellation map. It can be seen from the specific implementation provided by the above invention that it is precisely because the post-encoding bit group period is repeatedly arranged and the corresponding uncoded bit groups are different from each other, so that the symbols of the parallel path are uniformly mapped on the constellation map, so that the TCM code is Overall performance has improved. DRAWINGS 1 is a schematic diagram of a prior art TCM code modulation structure;
图 2为现有技术 16QAM集分割示意图;  2 is a schematic diagram of a 16QAM set partitioning in the prior art;
图 3为现有技术码率为 1/2卷积编码器结构示意图;  3 is a schematic diagram showing the structure of a prior art code rate 1/2 convolutional encoder;
图 4为现有技术 2/3 64QAM TCM编码器结构示意图;  4 is a schematic structural diagram of a prior art 2/3 64QAM TCM encoder;
图 5为现有技术 TCM的 64QAM星座映射图;  5 is a 64QAM constellation map of a prior art TCM;
图 6为现有技术 5/6 64QAM TCM编码器结构示意图;  6 is a schematic structural diagram of a prior art 5/6 64QAM TCM encoder;
图 7为现有技术 3/4 256QAM TCM编码器结构示意图;  7 is a schematic structural diagram of a prior art 3/4 256QAM TCM encoder;
图 8为现有技术 TCM的 256QAM星座映射图;  8 is a 256QAM constellation map of a prior art TCM;
图 9为现有技术 7/8 256QAM TCM编码器结构示意图;  9 is a schematic structural diagram of a prior art 7/8 256QAM TCM encoder;
图 10A现有技术并行路径距离示意图;  10A is a schematic diagram of a prior art parallel path distance;
图 10B现有技术并行路径距离示意图;  10B is a schematic diagram of a prior art parallel path distance;
图 11为本发明第一实施例提供的方法流程图;  FIG. 11 is a flowchart of a method according to a first embodiment of the present invention;
图 12A为本发明第一实施例提供的 TCM的 64QAM星座映射图; 图 12B为本发明第一实施例提供的 TCM的 64QAM星座映射图; 图 12C为本发明第一实施例提供的 TCM的 64QAM星座映射图; 图 13A为本发明第一实施例提供的 TCM的 256QAM星座映射图; 图 13B为本发明第一实施例提供的 TCM的 256QAM星座映射图; 图 14为本发明第二实施例提供的译码时确定欧氏距离最小的信号点 的示意图;  12A is a 64QAM constellation map of a TCM according to a first embodiment of the present invention; FIG. 12B is a 64QAM constellation map of a TCM according to a first embodiment of the present invention; FIG. 12C is a 64QAM of a TCM according to a first embodiment of the present invention; FIG. 13A is a 256QAM constellation map of a TCM according to a first embodiment of the present invention; FIG. 13B is a 256QAM constellation map of a TCM according to a first embodiment of the present invention; FIG. 14 is a second embodiment of the present invention. A schematic diagram of determining a signal point with the smallest Euclidean distance during decoding;
图 15为本发明实施例提供的 2/3 64QAM TCM码 BER仿真结果比较 示意图;  15 is a schematic diagram of comparison of 2/3 64QAM TCM code BER simulation results according to an embodiment of the present invention;
图 16为本发明实施例提供的 5/6 64QAM TCM码 BER仿真结果比较 示意图;  16 is a schematic diagram of comparison of 5/6 64QAM TCM code BER simulation results according to an embodiment of the present invention;
图 17为本发明实施例提供的 3/4 256QAM TCM码 BER仿真结果比较 示意图;  FIG. 17 is a schematic diagram showing comparison of BER simulation results of 3/4 256QAM TCM codes according to an embodiment of the present invention; FIG.
图 18为本发明实施例提供的 7/8 256QAM TCM码 BER仿真结果比较 示意图; FIG. 18 is a comparison of BER simulation results of 7/8 256QAM TCM codes according to an embodiment of the present invention. Schematic diagram
图 19为本发明第三实施例提供的装置结构示意图;  FIG. 19 is a schematic structural diagram of a device according to a third embodiment of the present invention; FIG.
图 20为本发明第四实施例提供的装置结构示意图。 具体实施方式  FIG. 20 is a schematic structural diagram of a device according to a fourth embodiment of the present invention. detailed description
本发明实施例提出的 2/3 64QAM、 5/6 64QAM, 3/4 256QAM, 7/8 256QAM 的 TCM编码结构的优选的调制映射方式并非只有唯——种, 而 是满足某种映射规则的调制映射方式的集合。 下面对这种映射规则进行描 述。  The preferred modulation mapping method of the TCM coding structure of 2/3 64QAM, 5/6 64QAM, 3/4 256QAM, 7/8 256QAM proposed by the embodiment of the present invention is not only a kind of only one kind, but a certain mapping rule is satisfied. A collection of modulation mapping methods. This mapping rule is described below.
现有技术中 2/3 64QAM、 5/6 64QAM、 3/4 256QAM, 7/8 256QAM 的 2/3 64QAM, 5/6 64QAM, 3/4 256QAM, 7/8 256QAM in the prior art
TCM码的编码后比特组的比特数都是 4个 (编码后比特组指的是经过卷 积编码后的一个或多个输出比特) , 分别映射到星座图上的 I路与 Q路, 每一路分别映射 2个比特。 设调制阶数为 M, 则未编码比特组的比特数为 (M-4)个, 分别映射在 I/Q每一路上的比特数为(M-4)/2个 (未编码比特组 指的是直通比特, 不经过卷积编码的一个或多个输出比特) 。 The number of bits of the encoded bit group of the TCM code is four (the encoded bit group refers to one or more output bits after convolutional coding), and is mapped to the I and Q paths on the constellation, respectively. Each channel maps 2 bits. Let the modulation order be M, then the number of bits of the uncoded bit group is (M-4), and the number of bits mapped on each path of I/Q is (M-4)/2 (uncoded bit group refers to Is a pass-through bit, one or more output bits that are not convolutionally encoded).
对于映射在 I/Q每一路上的编码后比特组的序列需满足周期重复的特 性。 而对于重复的编码后比特组, 所对应的未编码比特组需不一样。 未编 码比特组的顺序无特殊要求。  The sequence of coded bit groups mapped on each I/Q of the path needs to satisfy the characteristics of periodic repetition. For repeated coded bit groups, the corresponding uncoded bit groups need to be different. The order of uncoded bit groups has no special requirements.
这一规则保证了并行路径上的 TCM编码输出信号点在 I路与 Q路上 的映射是均匀对称的, 而且符合并行路径上 TCM编码输出信号点之间的 欧氏距离最大化的原则。  This rule ensures that the TCM coded output signal points on the parallel path are uniformly symmetrical on the I and Q paths, and conforms to the principle of maximizing the Euclidean distance between the TCM coded output signal points on the parallel path.
映射在 I路与 Q路的编码后比特组序列需要分别满足格雷码映射的规 贝' J , 即序列中的任意两个相邻编码后比特组之间, 只有一个比特是不相同 的。  The encoded bit group sequence mapped in the I path and the Q path needs to satisfy the Gray code mapping rule respectively, that is, only one bit between the two adjacent coded bit groups in the sequence is different.
本发明实施例提供的满足上述映射规则的网格编码调制码的编码调 制方法包括: 建立调制阶数大于 4的 QAM星座图作为网格编码调制码的星座映射 图, 使映射在所述星座映射图 I路和 Q路上的编码后比特组在所述 I路和 Q路上分别周期重复排列, 且使与每一次周期重复排列的编码后比特组对 应的未编码比特组彼此不同; 根据原始比特信息组得到包括编码后比特组 和未编码比特组的星座索引; 根据所述星座索引在所述星座映射图中确定 信号点作为最终发射的网格编码调制码信号。 The coding and modulation method of the trellis coded modulation code that satisfies the above mapping rule provided by the embodiment of the present invention includes: Establishing a QAM constellation diagram with a modulation order greater than 4 as a constellation map of the trellis coded modulation code, so that the coded bit groups mapped on the constellation map I and Q are periodically repeated on the I and Q paths, respectively. Arranging, and making uncoded bit groups corresponding to the coded bit groups repeatedly arranged in each cycle different from each other; obtaining a constellation index including the encoded bit group and the uncoded bit group according to the original bit information group; The signal point is determined in the constellation map as the finally transmitted trellis coded modulation code signal.
本发明实施例提供的满足上述映射规则的网格编码调制码的译码方 法包括:  The decoding method of the trellis coded modulation code that satisfies the above mapping rule provided by the embodiment of the present invention includes:
建立调制阶数大于 4的 QAM星座图作为网格编码调制码的星座映射 图, 使映射在所述星座映射图 I路和 Q路上的编码后比特组在所述 I路和 Q路上分别周期重复排列, 且使与每一次周期重复排列的编码后比特组对 应的未编码比特组彼此不同; 根据所述星座映射图对待译码信号进行译码 处理。  Establishing a QAM constellation diagram with a modulation order greater than 4 as a constellation map of the trellis coded modulation code, so that the coded bit groups mapped on the constellation map I and Q are periodically repeated on the I and Q paths, respectively. Arranging, and making the uncoded bit groups corresponding to the coded bit groups repeatedly arranged in each cycle different from each other; performing decoding processing on the signals to be decoded according to the constellation map.
本发明提供的第一实施例是一种网格编码调制码(TCM )的编码调制 方法, 方法流程如图 11所示, 包括:  The first embodiment provided by the present invention is a coding and modulation method of a trellis coded modulation code (TCM). The method flow is as shown in FIG. 11, and includes:
步骤 101 : 建立 5/6 64QAM TCM的星座映射图如图 12A所示, 星座映 射图中的编码后比特组的 4个比特分别映射到 I路的 b4b3与 Q路的 blbO, b4b3或 blbO的组合一共有 22=4种, 所以每一路上编码后比特序列重复的 周期为 4。 2个未编码比特分别映射到 I路的 b5和 Q路的 b2。 对于重复的 b4b3 , b5的值需不一样。 同理, 对于重复的 blbO, b2的值也需不一样。 其中的优选的映射方式如下所描述。 Step 101: Establish a constellation map of the 5/6 64QAM TCM as shown in FIG. 12A. The four bits of the encoded bit group in the constellation map are respectively mapped to the combination of b4b3 of the I path and blbO, b4b3 or blbO of the Q path. There are 2 2 = 4 in total, so the period of the bit sequence repetition after encoding on each road is 4. The two uncoded bits are mapped to b5 of the I path and b2 of the Q path, respectively. For repeated b4b3, the value of b5 needs to be different. For the same reason, for repeated blbO, the value of b2 needs to be different. The preferred mapping method therein is as follows.
I/Q路坐标值 7A 5A 3A A -A -3A -5A -7A ( A为星座 图功率归一化因子)  I/Q path coordinate value 7A 5A 3A A -A -3A -5A -7A (A is the constellation diagram power normalization factor)
I路 b4b3 10 00 01 11 10 00 01 11  I road b4b3 10 00 01 11 10 00 01 11
I路 b5 0 0 0 0 1 1 1 1 (也可以是 0 1 1 I road b5 0 0 0 0 1 1 1 1 (may also be 0 1 1
0 1 0 0 1 , 无特殊顺序要求) Q路 blbO 01 00 10 11 01 00 10 11 0 1 0 0 1 , no special order required) Q road blbO 01 00 10 11 01 00 10 11
Q路 b2 0 0 0 0 1 1 1 1 (也可以是 00 111100, 无特殊顺序要求)  Q road b2 0 0 0 0 1 1 1 1 (can also be 00 111100, no special order required)
步骤 102: 接收一原始比特信息组 "10011" (分别对应  Step 102: Receive a raw bit information group "10011" (corresponding respectively
u4u3u2ulu0 )进入 5/664QAM TCM编码器。 "1001 Γ 的输入顺序为 第一个 "1" 第一个到达, 第一个 "0" 第二个到达, 第二个 "0" 第三个 到达, 第二个 "1" 第四个到达, 第三个 "1" 最后到达。 U4u3u2ulu0) Enter the 5/664QAM TCM encoder. The input order of "1001 Γ is the first "1" first arrival, the first "0" second arrival, the second "0" third arrival, the second "1" fourth arrival The third "1" finally arrived.
步骤 103: TCM编码器对原始比特信息组 "10011" 编码后得到包 括编码后比特组和未编码比特组的星座索引。 TCM编码器部分使用码率 为 3/4的卷积码 (原 1/2卷积码经过打孔使码率变为 3/4)。 对 "01 Γ 进行 3/4的卷积编码, 如卷积编码器 6个寄存器初始值均为 0, 则输出为 "111 0" (分别对应于 c3c2clc0) , 顺序为第一个 "1" 先输出, 第二个 "1" 第二, 第三个 "1" 第三, "0" 最后。 未编码比特组 "1" (u4) 与编码 后比特组 " 11" (c3c2)合为一组 3比特的星座索引 "i l l" ( b5b4b3 ) , 映射到 I路, 其中后两个 "1" (b4b3 )为编码后比特组, 第一个 "1" ( b5 ) 为未编码比特组。 "010" (u3clc0)合为一组 3比特的星座索引 "010" ( b2blb0 ) , 映射到 Q路, 其中后面两个比特 "10" (blbO) 为编码后 比特组, 第一个 "0" (b2) 为未编码比特组。  Step 103: The TCM encoder encodes the original bit information group "10011" to obtain a constellation index including the encoded bit group and the uncoded bit group. The TCM encoder section uses a convolutional code with a code rate of 3/4 (the original 1/2 convolutional code is punctured to make the code rate 3/4). For "01 卷 3/4 convolutional coding, if the initial value of the six registers of the convolutional encoder is 0, the output is "111 0" (corresponding to c3c2clc0 respectively), and the order is the first "1" first. Output, second "1" second, third "1" third, "0" last. Uncoded bit group "1" (u4) combined with encoded bit group "11" (c3c2) The 3-bit constellation index "ill" (b5b4b3) is mapped to the I path, where the last two "1"s (b4b3) are the encoded bit groups, and the first "1" (b5) is the uncoded bit group. "(u3clc0) is a set of 3-bit constellation index "010" (b2blb0) mapped to the Q path, where the last two bits "10" (blbO) are the encoded bit group, the first "0" (b2) ) is an uncoded bit group.
步骤 104:根据得到的 I路星座索引 "111"和 Q路星座索引 "010" , 在步骤 101建立 5/664QAM TCM的星座映射图 (如图 12A所示) 中确定 I路坐标为 -7、 Q路坐标为 3信号点, 并将该信号点作为最终发射的 TCM 信号。  Step 104: According to the obtained I-way constellation index "111" and the Q-way constellation index "010", the constellation map of the 5/664QAM TCM is established in step 101 (as shown in FIG. 12A), and the I-way coordinate is determined to be -7. The Q path coordinates are 3 signal points and the signal point is used as the final transmitted TCM signal.
根据上面所描述的技术原理, 同样还可以得到 5/664QAM TCM的星 座映射图如图 12B和图 12C所示, 这说明 5/664QAMTCM的星座映射图 并非唯——种, 而是满足前面所描述的技术原理的集合。  According to the technical principle described above, the constellation map of 5/664QAM TCM can also be obtained as shown in FIG. 12B and FIG. 12C, which indicates that the constellation map of 5/664QAMTCM is not unique, but satisfies the foregoing description. A collection of technical principles.
根据上面所描述的技术原理, 同样还可以得到 3/4256QAM、 7/8 256QAM的星座映射图, 并确定最终发射的 TCM信号, 这里就不再赘述 了。 256QAM的优选方案中的星座映射图如图 13A所示, 同样 256QAM 的星座映射图也不是图 13A所示的唯——种, 还可以如图 13B所示, 是 满足前面所描述的技术原理的集合。 According to the technical principle described above, 3/4256QAM, 7/8 can also be obtained. The constellation map of 256QAM, and determine the final transmitted TCM signal, will not be described here. The constellation map in the preferred scheme of 256QAM is shown in FIG. 13A, and the constellation map of the same 256QAM is not the only one shown in FIG. 13A, and can also be as shown in FIG. 13B, which satisfies the technical principle described above. set.
本发明实施例中所描述的技术方案使得同一子集内的信号点在星座 映射图上, 特别是 Q路上映射均匀, 同一子集内的信号点的最小欧氏距离 为 4大于现有技术中的最小欧氏距离 1 , TCM码的整体性能得到提升。  The technical solution described in the embodiments of the present invention makes signal points in the same subset on the constellation map, especially on the Q road, and the minimum Euclidean distance of the signal points in the same subset is greater than 4 in the prior art. The minimum Euclidean distance of 1, the overall performance of the TCM code is improved.
本发明提供的第二实施例是一种网格编码调制码( TCM )的译码方法, 以 5/6 64QAM TCM码为例, 包括:  A second embodiment of the present invention provides a trellis coded modulation code (TCM) decoding method, which is exemplified by a 5/6 64QAM TCM code, and includes:
步骤 201 : 建立 5/6 64QAM TCM的星座映射图, 如图 12A所示, 具 体方案与步骤 101相同。  Step 201: Establish a constellation map of the 5/6 64QAM TCM. As shown in FIG. 12A, the specific scheme is the same as step 101.
根据步骤 201建立星座映射图后, 根据该星座图, 利用现有技术对待 译码信号进行后续译码处理, 作为优选的译码处理方案可采用子集译码和 软判决 Viterbi译码。  After the constellation map is established according to step 201, according to the constellation diagram, the decoding signal is subjected to subsequent decoding processing by using the prior art. As a preferred decoding processing scheme, subset decoding and soft decision Viterbi decoding may be employed.
步骤 202: 子集译码, 在图 12A的星座映射图 16个子集的每个子集 的 4个信号点中, 找出与接收符号欧氏距离最小的信号点。 译码时确定欧 氏距离最小的信号点的示意图如图 14所示, 圓圏为接收信号点位置, 编 码后比特组 "0000" (b4b3blb0)所对应的子集为图 14中的四个信号点, 则 左上信号点为子集译码结果。  Step 202: Sub-set decoding, in the four signal points of each subset of the 16 subsets of the constellation map of Fig. 12A, find the signal point with the smallest Euclidean distance from the received symbol. The schematic diagram of determining the signal point with the smallest Euclidean distance during decoding is shown in Fig. 14. The circle is the position of the received signal point, and the subset corresponding to the bit group "0000" (b4b3blb0) after encoding is the four signals in Fig. 14. Point, then the upper left signal point is the subset decoding result.
步骤 203: 软判决 Viterbi译码, 在子集译码的结果中, 得到关于 16 个编码后比特组的欧氏距离作为其软判决度量值。 将上述软判决度量值代 入 Viterbi译码器中进行译码操作, 即可得到对原始比特信息组的估计值 (译码结果) 。  Step 203: Soft-decision Viterbi decoding, in the result of the subset decoding, obtains the Euclidean distance of the 16 encoded bit groups as its soft decision metric. By substituting the soft decision metric value into the Viterbi decoder for decoding operation, an estimated value (decoding result) for the original bit block can be obtained.
2/3 64QAM、 3/4 256QAM、 7/8 256QAMTCM码的译码过程的技术原 理和上面所描述的 5/6 64QAM TCM码的译码过程相同, 这里就不再赘述 了。 译码过程根据本发明实施例提供的星座图进行译码, 使得同一子集内 的信号点在星座映射图上, 特别是 Q路上映射均匀, 同一子集内的信号点 的最小欧氏距离为 4大于现有技术中的最小欧氏距离 1 , 并行路径上的 TCM编码输出信号点的最小欧氏距离大于现有技术的最小欧氏距离, 在 一定的信噪比下, 其译码出错的概率小于现有技术的译码出错的概率, TCM码的整体性能得到提升。 The technical principle of the decoding process of 2/3 64QAM, 3/4 256QAM, 7/8 256QAMTCM code is the same as that of the 5/6 64QAM TCM code described above, and will not be described here. The decoding process is performed according to the constellation diagram provided by the embodiment of the present invention, so that the signal points in the same subset are uniformly mapped on the constellation map, especially on the Q road, and the minimum Euclidean distance of the signal points in the same subset is 4 is larger than the minimum Euclidean distance 1 in the prior art, and the minimum Euclidean distance of the TCM coded output signal point on the parallel path is larger than the minimum Euclidean distance of the prior art, and the decoding error occurs under a certain signal to noise ratio. The probability is less than the probability of decoding errors in the prior art, and the overall performance of the TCM code is improved.
本发明实施例中所描述的 TCM码可适用于 Wimax SCa下的 TCM码, 作为其改良的方案。 也可适用于其它使用了这种 TCM码的通信系统。  The TCM code described in the embodiment of the present invention can be applied to the TCM code under Wimax SCa as an improved solution. It is also applicable to other communication systems that use such TCM codes.
现有技术中定义的 2/3 64QAM、 5/6 64QAM、 3/4 256QAM, 7/8 256QAM TCM码与本发明实施例所描述的优选 TCM码的 BER ( bit error rate 误比特率)仿真结果的比较如图 15、 图 16、 图 17、 图 18所示。 其中 Wimax表示 Wimax协议中定义的 TCM码, MY表示本发明实施例所描述 的优选 TCM码, 信道为 AWGN信道, Es/Nt为码元能量与单位带宽内噪 声功率之比, 亦即归一化信噪比。  BER (bit error rate) simulation results of 2/3 64QAM, 5/6 64QAM, 3/4 256QAM, 7/8 256QAM TCM codes defined in the prior art and preferred TCM codes described in the embodiments of the present invention The comparison is shown in Fig. 15, Fig. 16, Fig. 17, and Fig. 18. Where Wimax represents the TCM code defined in the Wimax protocol, MY represents the preferred TCM code described in the embodiment of the present invention, the channel is the AWGN channel, and Es/Nt is the ratio of the symbol energy to the noise power in the unit bandwidth, that is, normalized. Signal to noise ratio.
可见, 相比较于原 Wimax协议中定义的 2/3 64QAM、 5/6 64QAM、 3/4 It can be seen that compared to the 2/3 64QAM, 5/6 64QAM, 3/4 defined in the original Wimax protocol.
256QAM、 7/8 256QAM TCM码, 本发明实施例所描述的优选 TCM码的性 能有显著改善。 在 BER=10-6处, 有 5dB~9dB的增益。 可见, 在相同的信噪 比下, 本发明实施例所描述的技术方案与现有技术相比, TCM码的整体性 能得到提升。 The performance of the preferred TCM code described in the embodiments of the present invention is significantly improved by the 256QAM, 7/8 256QAM TCM code. At BER = 10- 6, there is a gain of 5dB ~ 9dB. It can be seen that, under the same signal-to-noise ratio, the technical solution described in the embodiments of the present invention improves the overall performance of the TCM code compared with the prior art.
而且本发明实施例所设计的 TCM码可以维持原 Wimax协议定义的 Moreover, the TCM code designed by the embodiment of the present invention can maintain the definition of the original Wimax protocol.
TCM码的编码部分结构不变, 只需要改变星座映射图即可获得明显增益, 与原协议的兼容性好。 The coding part of the TCM code has the same structure, and only needs to change the constellation map to obtain significant gain, which is compatible with the original protocol.
本发明提供的第三实施例是一种 TCM的编码调制装置, 其结构如图 19所示, 包括:  The third embodiment of the present invention is a code modulation device of a TCM, and its structure is as shown in FIG. 19, including:
存储模块 301 : 用于存储调制阶数大于 4的正方形 QAM星座图作为 The storage module 301 is configured to store a square QAM constellation diagram with a modulation order greater than 4 as
TCM的星座映射图, 映射在所述星座映射图 I路和 Q路上的编码后比特 组在所述 I路和 Q路上分别周期重复排列, 与每一次周期重复排列的编码 后比特组对应的未编码比特组彼此不同; a constellation map of the TCM, mapping the encoded bits on the I and Q paths of the constellation map The groups are repeatedly arranged periodically on the I path and the Q path, and the uncoded bit groups corresponding to the coded bit groups repeatedly arranged in each cycle are different from each other;
星座索引获取模块 302: 用于根据原始比特信息组得到包括编码后比 特组和未编码比特组的星座索引;  a constellation index obtaining module 302: configured to obtain, according to the original bit information group, a constellation index including the encoded bit group and the uncoded bit group;
TCM信号确认模块 303:用于根据所述星座索引在所述星座映射图中 确定信号点作为最终发射的 TCM信号。  The TCM signal confirmation module 303 is configured to determine a signal point in the constellation map according to the constellation index as a final transmitted TCM signal.
本发明提供的第四实施例是一种网格编码调制码( TCM )的译码装置, 其结构如图 20所示, 包括:  The fourth embodiment of the present invention provides a trellis coded modulation code (TCM) decoding device, and the structure thereof is as shown in FIG. 20, including:
存储模块 401 : 用于存储调制阶数大于 4的正方形 QAM星座图作为 TCM的星座映射图, 映射在所述星座映射图 I路和 Q路上的编码后比特 组在所述 I路和 Q路上分别周期重复排列, 与每一次周期重复排列的编码 后比特组对应的未编码比特组彼此不同;  The storage module 401 is configured to store a square QAM constellation diagram with a modulation order greater than 4 as a constellation map of the TCM, and the coded bit groups mapped on the constellation map I and Q paths are respectively on the I road and the Q road. The cycle is repeatedly arranged, and the uncoded bit groups corresponding to the coded bit groups repeatedly arranged in each cycle are different from each other;
译码模块 402:用于根据所述星座映射图对待译码信号进行译码处理。 具体地说, 在实际应用中, 本实施例中所采用的星座图可以与本发明  The decoding module 402 is configured to perform decoding processing on the signal to be decoded according to the constellation map. Specifically, in practical applications, the constellation diagram used in this embodiment can be combined with the present invention.
发明的精神和范围。 这样, 倘若本发明的这些修改和变型属于本发明权利要 求及其等同技术的范围之内, 则本发明也意图包含这些改动和变型在内。 The spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of the inventions

Claims

权 利 要 求 Rights request
1、 一种网格编码调制码的编码调制方法, 其特征在于, 包括: 建立调制阶数大于 4的正交幅度调制 QAM星座图作为网格编码调制 码的星座映射图,使映射在所述星座映射图 I路和 Q路上的编码后比特组 在所述 I路和 Q路上分别周期重复排列, 且使与每一次周期重复排列的编 码后比特组对应的未编码比特组彼此不同; A coding and modulation method for a trellis coded modulation code, comprising: establishing a quadrature amplitude modulation QAM constellation diagram with a modulation order greater than 4 as a constellation map of a trellis coded modulation code, so that the mapping is performed in the The coded bit groups on the I-channel and the Q-channel of the constellation map are repeatedly arranged periodically on the I-channel and the Q-channel, respectively, and the uncoded bit groups corresponding to the coded bit groups repeatedly arranged in each cycle are different from each other;
根据原始比特信息组得到包括编码后比特组和未编码比特组的星座 索引;  Obtaining a constellation index including the encoded bit group and the uncoded bit group according to the original bit information group;
根据所述星座索引在所述星座映射图中确定信号点作为最终发射的 网格编码调制码信号。  A signal point is determined in the constellation map as the final transmitted trellis coded modulation code signal based on the constellation index.
2、 如权利要求 1所述的方法, 其特征在于, 在所述星座映射图 I路 或 Q路上任意两个相邻编码后比特组之间, 只有一个比特不同。  2. The method according to claim 1, wherein only one bit is different between any two adjacent coded bit groups on the constellation map I or Q path.
3、 如权利要求 2所述的方法, 其特征在于, 所述星座映射图包括网 格编码调制码的 64QAM星座映射图。  3. The method of claim 2, wherein the constellation map comprises a 64QAM constellation map of a grid coded modulation code.
4、如权利要求 3所述的方法,其特征在于,采用码率为 2/3的 64QAM 网格编码调制码编码器对原始比特信息组进行处理, 得到包括所述编码后 比特组和未编码比特组的星座索引, 或  The method according to claim 3, wherein the original bit information block is processed by a 64QAM trellis coded modulation code encoder having a code rate of 2/3, and the encoded bit group and the uncoded are obtained. The constellation index of the bit group, or
采用码率为 5/6的 64QAM 网格编码调制码编码器对原始比特信息组 进行处理, 得到包括编码后比特组和未编码比特组的星座索引。  The original bit information block is processed by a 64QAM trellis coded modulation code encoder with a code rate of 5/6 to obtain a constellation index including the encoded bit group and the uncoded bit group.
5、 如权利要求 2所述的方法, 其特征在于, 所述星座映射图包括网 格编码调制码的 256QAM星座映射图。  5. The method of claim 2, wherein the constellation map comprises a 256QAM constellation map of a grid coded modulation code.
6、如权利要求 5所述的方法,其特征在于,采用码率为 3/4的 256QAM 网格编码调制码编码器对原始比特信息组进行处理, 得到包括所述编码后 比特组和未编码比特组的星座索引, 或  The method according to claim 5, wherein the original bit block is processed by a 256QAM trellis coded modulation code encoder having a code rate of 3/4, and the bit group and the uncoded group are obtained. The constellation index of the bit group, or
采用码率为 7/8的 256QAM 网格编码调制码编码器对原始比特信息 组进行处理, 得到包括所述编码后比特组和未编码比特组的星座索引。  The original bit information group is processed by a 256QAM trellis coded modulation code encoder having a code rate of 7/8 to obtain a constellation index including the coded bit group and the uncoded bit group.
7、 一种网格编码调制码的译码方法, 其特征在于, 包括: 建立调制阶数大于 4的正交幅度调制 QAM星座图作为网格编码调制 码的星座映射图,使映射在所述星座映射图 I路和 Q路上的编码后比特组 在所述 I路和 Q路上分别周期重复排列, 且使与每一次周期重复排列的编 码后比特组对应的未编码比特组彼此不同; 7. A method for decoding a trellis coded modulation code, comprising: Establishing a quadrature amplitude modulation QAM constellation with a modulation order greater than 4 as a constellation map of the trellis coded modulation code, so that the coded bit groups mapped on the constellation map I and Q are in the I path and Q Repeatedly arranging the cycles on the way, respectively, and making the uncoded bit groups corresponding to the coded bit groups repeatedly arranged in each cycle different from each other;
根据所述星座映射图对待译码信号进行译码处理。  Decoding the signal to be decoded according to the constellation map.
8、 如权利要求 7所述的方法, 其特征在于, 在星座映射图 I路或 Q 路上任意两个相邻编码后比特组之间, 只有一个比特不同。  8. The method according to claim 7, wherein only one bit is different between any two adjacent coded bit groups on the constellation map I or Q path.
9、 如权利要求 8所述的方法, 其特征在于, 所述网格编码调制码的 星座映射图包括网格编码调制码的 64QAM星座映射图。  9. The method of claim 8, wherein the constellation map of the trellis coded modulation code comprises a 64QAM constellation map of trellis coded modulation codes.
10、 如权利要求 8所述的方法, 其特征在于, 所述网格编码调制码的 星座映射图包括网格编码调制码的 256QAM星座映射图。  10. The method according to claim 8, wherein the constellation map of the trellis coded modulation code comprises a 256QAM constellation map of trellis coded modulation codes.
11、 一种网格编码调制码的编码调制装置, 其特征在于, 包括: 存储模块: 用于存储调制阶数大于 4的正交幅度调制 QAM星座图作 为网格编码调制码的星座映射图, 映射在所述星座映射图 I路和 Q路上的 编码后比特组在所述 I路和 Q路上分别周期重复排列, 与每一次周期重复 星座索引获取模块:用于根据原始比特信息组得到包括编码后比特组 和未编码比特组的星座索引;  A coded modulation device for a trellis coded modulation code, comprising: a storage module: configured to store a quadrature amplitude modulation QAM constellation diagram with a modulation order greater than 4 as a constellation map of a trellis coded modulation code, The coded bit groups mapped on the constellation map I and Q paths are repeatedly arranged periodically on the I path and the Q path, and the constellation index acquisition module is repeated with each cycle: used to obtain the coding according to the original bit information group. Constellation index of the latter bit group and the uncoded bit group;
网格编码调制码信号确认模块:用于根据所述星座索引在所述星座映 射图中确定信号点作为最终发射的网格编码调制码信号。  A trellis coded modulation code signal confirmation module is configured to determine a signal point in the constellation map according to the constellation index as a trellis coded modulation code signal for final transmission.
12、 一种网格编码调制码的译码装置, 其特征在于, 包括: 存储模块: 用于存储调制阶数大于 4的正交幅度调制 QAM星座图作 为网格编码调制码的星座映射图, 映射在所述星座映射图 I路和 Q路上的 编码后比特组在所述 I路和 Q路上分别周期重复排列, 与每一次周期重复 译码模块: 用于根据所述星座映射图对待译码信号进行译码处理。  12. A trellis coded modulation code decoding apparatus, comprising: a storage module: configured to store a quadrature amplitude modulation QAM constellation diagram with a modulation order greater than 4 as a constellation map of a trellis coded modulation code, The coded bit groups mapped on the I and Q paths of the constellation map are repeatedly arranged periodically on the I and Q paths, and the decoding module is repeated with each period: used to decode according to the constellation map The signal is decoded.
PCT/CN2008/071349 2007-07-10 2008-06-18 Encoding modulation method,decoding method and apparatus of trellis coded modulation code WO2009006812A1 (en)

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