WO2017024456A1 - Procédé et appareil de modulation et de démodulation de code - Google Patents

Procédé et appareil de modulation et de démodulation de code Download PDF

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Publication number
WO2017024456A1
WO2017024456A1 PCT/CN2015/086424 CN2015086424W WO2017024456A1 WO 2017024456 A1 WO2017024456 A1 WO 2017024456A1 CN 2015086424 W CN2015086424 W CN 2015086424W WO 2017024456 A1 WO2017024456 A1 WO 2017024456A1
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Prior art keywords
subcarriers
bit sequence
modulation symbol
bits
group
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PCT/CN2015/086424
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English (en)
Chinese (zh)
Inventor
刘晟
陈特彦
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华为技术有限公司
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Priority to PCT/CN2015/086424 priority Critical patent/WO2017024456A1/fr
Publication of WO2017024456A1 publication Critical patent/WO2017024456A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes

Definitions

  • the present invention relates to the field of communications, and in particular, to a code modulation and demodulation method and apparatus.
  • Dual Carrier Modulation (Dual Carrier Modulation, DCM for short) is a coded modulation technique suitable for Orthogonal Frequency-Division Multiplexing (OFDM) systems.
  • OFDM Orthogonal Frequency-Division Multiplexing
  • a plurality of modulation and coding schemes (English name: Modulation Coding Scheme, MCS for short) are stored in a transmitting end, and each scheme has a different modulation scheme.
  • MCS0 adopts binary phase shift keying modulation.
  • MCS2 uses quadrature phase shift keying (English full name: Quadrature Phase Shift Keying, referred to as: QPSK) modulation mode
  • DCM technology can be replaced by higher order modulation
  • the low-order modulation method replaces the QPSK modulation of the MCS2 with the hexadecimal quadrature amplitude modulation (English name: Quadrature Amplitude Modulation, QAM for short), which can only be mapped compared to each constellation point in the QPSK constellation.
  • Two information bits are added to the subcarriers, and each constellation point in the 16-QAM constellation map can map four information bits to the subcarriers, thereby doubling the bit information that the transmitting end can transmit on the same carrier.
  • the transmitting end obtains the encoded bit sequence after channel coding the information bits, and
  • the coded bit sequence is subjected to interleaving processing and repeated processing to obtain two sets of identical bit sequences, such as bit sequence 1 and bit sequence 2 in FIG. 1, and the bit sequence 1 is mapped to the N sub-band through the 16-QAM constellation diagram 1.
  • the first N/2 subcarriers in the carrier, the bit sequence 2 is transmitted to the last N/2 subcarriers in the N subcarrier through the 16-QAM constellation diagram 2, and then passed the inverse fast Fourier transform (English full name: Inverse Fast Fourier) Transform, abbreviation: IFFT) transforms to the time domain, and finally adds a cyclic prefix (English full name: Cyclic Prefix, referred to as CP) OFDM symbol, such that since the first N/2 subcarriers and the last N subcarriers of the N subcarriers respectively carry the bit sequence, frequency domain diversity is implemented, and the receiving end receives two identical bit sequences before and after, The two bit sequences can be combined to obtain a diversity set in the frequency domain and gain.
  • IFFT inverse Fast Fourier transform
  • CP Cyclic Prefix
  • the DCM technical solution in the prior art only implements the diversity transmission of the bit sequence in the frequency domain to obtain the diversity and gain in the frequency domain.
  • the prior art does not consider how to improve the coding gain of the bit sequence.
  • the coding gain is related to the number of redundant bits in the bit sequence.
  • the embodiments of the present invention provide a code modulation and demodulation method and apparatus, which can improve the coding gain of a bit sequence transmitted by a transmitting end while obtaining diversity and gain.
  • a code modulation method including:
  • the encoded bit sequence includes M bits, N is a positive integer greater than 1, and M is a positive integer greater than N;
  • the first constellation diagram, the second constellation diagram, and the third constellation diagram adopt the same modulation order ⁇ , where the modulation order The number of bits transmitted for a modulation symbol.
  • the first group of subcarriers is the first M 1 / ⁇ subcarriers in the transmission bandwidth
  • the second group of subcarriers is the last M 1 / ⁇ subcarriers in the transmission bandwidth
  • the third group of subcarriers The carrier is the remaining M 2 / ⁇ subcarriers in the transmission bandwidth.
  • the third set of subcarriers is M 2 / c per sub-carriers (2M 1 + M 2) / c sub-carriers in the transmission bandwidth; wherein, c is the greatest common divisor of 2M 1 and M 2;
  • the first group of subcarriers is the first half of the remaining subcarriers in the transmission bandwidth, and the second group of subcarriers is the latter half of the remaining subcarriers.
  • the method further includes:
  • a code modulation method which includes:
  • N information bits are subjected to convolutional coding with a coding rate of 1/2 to obtain an encoded bit sequence;
  • the coded bit sequence includes 2N bits, and N is a positive integer greater than one;
  • the coded bit sequence is A 1 B 1 A 2 B 2 A 3 B 3 . . . A N B N , then determining the bit sequence M 1 bits for repeated transmission and M 2 bits not used for repeated transmission, including:
  • M 1 bits are selected for repeated transmission, and it is determined that the remaining M 2 bits in the encoded bit sequence are not used for repeated transmission.
  • the subcarriers in the transmission bandwidth are divided into four subbands, where each subband includes the same number of Subcarrier
  • the first group of subcarriers is the first one of the four subbands
  • the second group of subcarriers is a third subband of the 4 subbands
  • the third subcarrier is a second subband and a fourth subband of the 4 subbands.
  • one of the two subcarriers in the transmission bandwidth is divided into one sub Transmitting a carrier to the third group of subcarriers;
  • the first half of the remaining subcarriers in the transmission bandwidth are divided into the first group of subcarriers, and the second half of the subcarriers are divided into the second group of subcarriers.
  • a code demodulation method including:
  • an OFDM symbol within a transmission bandwidth where the transmission bandwidth includes a first group of subcarriers, a second group of subcarriers, and a third group of subcarriers;
  • M 1 combined demodulated bit first constellation map and second constellation map of the first modulation symbol and the second modulation symbols according to the third demodulating the modulation symbols to obtain a third constellation bits M 2;
  • a method of code modulation including:
  • the first interleaved coded bit sequence is modulated into a first modulation symbol by using a first constellation, and the first modulation symbol is mapped to a first group of subcarriers in a transmission bandwidth;
  • the second interleaved coded bit sequence is modulated into a third modulation symbol by using the first constellation, and the third modulation symbol is post-mapped to a third group of subcarriers in the transmission bandwidth;
  • the first group of subcarriers is a first half subcarrier of an odd subcarrier in the transmission bandwidth, and the second group of subcarriers is the transmission bandwidth.
  • the third group of subcarriers is a first half of the even subcarriers of the transmission bandwidth
  • the fourth group of subcarriers is a second half of the even subcarriers of the transmission bandwidth.
  • the first interleaved coded bit sequence is modulated into the first modulation symbol by using the first constellation Previously, including:
  • the modulating the first interleaved coded bit sequence into the first modulation symbol by using the first constellation including:
  • the first interleaved coded bit sequence after the bit position is repeatedly switched, and the first interleaved coded bit sequence after the repeated bit position is repeatedly modulated into the second modulation symbol by using a second constellation.
  • the method further includes:
  • a method of code modulation including:
  • N information bits are subjected to convolutional coding with a coding rate of 1/2 to obtain an encoded bit sequence;
  • the coded bit sequence includes 2N bits, and N is a positive integer greater than one;
  • the first interleaved encoded bit sequence is modulated into a first modulation symbol by a first constellation pattern of a hexadecimal quadrature amplitude modulation 16-QAM modulation scheme, and the first modulation symbol is mapped to a first one of transmission bandwidths Group of subcarriers;
  • the first constellation pattern using a 16-QAM modulation scheme modulates the second interleaved coded bit sequence into a third modulation symbol, and maps the third modulation symbol to a third group of the transmission bandwidth Carrier wave
  • the first group of subcarriers is a first half subcarrier of an odd subcarrier in the transmission bandwidth
  • the second group of subcarriers is the transmission bandwidth.
  • the third group of subcarriers is a first half of the even subcarriers of the transmission bandwidth
  • the fourth group of subcarriers is a second half of the even subcarriers of the transmission bandwidth.
  • the method before the first interleaved coded bit sequence is modulated into the first modulation symbol by using the first constellation of the hexadecimal quadrature amplitude modulation 16-QAM modulation mode, the method includes:
  • the first constellation in the 16-QAM modulation mode modulates the first interleaved coded bit sequence into a first modulation symbol, including:
  • the repeating the first interleaved coded bit sequence, and modulating the repeated first interleaved coded bit sequence into a second modulation symbol by using a second constellation of the 16-QAM modulation mode including:
  • the first interleaved coded bit sequence after the bit position is repeatedly switched, and the first interleaved coded bit sequence after the repeated bit position is repeatedly modulated into the second modulation symbol by using the second constellation.
  • a method for code demodulation comprising:
  • the parsing the OFDM symbol to obtain the first interleaved coded bit sequence and the second interleaved coded bit sequence includes:
  • the first group of subcarriers is the first half of the subcarriers of the odd subcarriers
  • the second group of subcarriers is the second half of the subcarriers of the odd subcarriers
  • the third group of subcarriers Is the first half of the subcarriers of the even subcarriers in the transmission bandwidth
  • the fourth group of subcarriers is the second half of the subcarriers of the even subcarriers
  • a transmitting end including:
  • a channel coder for channel coding N information bits to obtain an encoded bit sequence;
  • the encoded bit sequence includes M bits, N is a positive integer greater than 1, and M is a positive integer greater than N;
  • a first interleaver configured to interleave the M 1 bits to obtain a first interleaved coded bit sequence
  • a modulating unit configured to modulate the first interleaved coded bit sequence into a first modulation symbol by using a first constellation, and map the first modulation symbol to a first group of subcarriers in a transmission bandwidth;
  • the modulating unit is further configured to: repeat the first interleaved coded bit sequence, modulate the repeated first interleaved coded bit sequence into a second modulation symbol by using a second constellation, and map the second modulation symbol a second set of subcarriers into the transmission bandwidth;
  • a second interleaver configured to interleave the M 2 bits to obtain a second interleaved coded bit sequence
  • the modulating unit is further configured to: modulate the second interleaved coded bit sequence into a third modulation symbol by using a third constellation, and map the third modulation symbol to a third group of the transmission bandwidth Subcarrier.
  • the first constellation diagram, the second constellation diagram, and the third constellation diagram adopt the same modulation order ⁇ , where the modulation order The number of bits transmitted for a modulation symbol.
  • the first group of subcarriers is the first M 1 / ⁇ subcarriers in the transmission bandwidth
  • the second group of subcarriers is the last M 1 / ⁇ subcarriers in the transmission bandwidth
  • the third group of subcarriers The carrier is the remaining M 2 / ⁇ subcarriers in the transmission bandwidth.
  • the method is as follows:
  • the third set of subcarriers is M 2 / c per sub-carriers (2M 1 + M 2) / c sub-carriers in the transmission bandwidth; wherein, c is the greatest common divisor of 2M 1 and M 2;
  • the first group of subcarriers is the first half of the remaining subcarriers in the transmission bandwidth, and the second group of subcarriers is the latter half of the remaining subcarriers.
  • the modulating unit is further configured to: perform the first modulation a symbol, the second modulation symbol and the third modulation symbol are inverse-Fourier Fourier Transform, and a cyclic prefix is added to obtain an orthogonal frequency division multiplexing OFDM symbol;
  • the transmitting end further includes a transmitting unit, configured to send the OFDM symbol.
  • a receiving end including:
  • An acquiring unit configured to acquire an OFDM symbol within a transmission bandwidth sent by the transmitting end, where the transmission bandwidth includes a first group of subcarriers, a second group of subcarriers, and a third group of subcarriers;
  • a parsing unit configured to parse the OFDM symbol to obtain a first modulation symbol on the first group of subcarriers, a second modulation symbol on the second group of subcarriers, and a third on the third group of subcarriers Three modulation symbols;
  • Demodulation means for demodulating joint according to the first constellation map and second constellation map of the first modulation symbol and the second modulation symbol to obtain M 1 bit, according to the third third constellation
  • a decoding unit configured to recombine the M 1 bit and the M 2 bit, and obtain the N information bits by channel decoding.
  • a transmitting end comprising:
  • a channel coder for channel coding a plurality of information bits to obtain an encoded bit sequence
  • a first interleaver configured to perform interleaving processing on the odd bit sequence included in the encoded bit sequence to obtain a first interleaved coded bit sequence
  • a second interleaver configured to perform interleaving processing on the even bit sequence included in the encoded bit sequence to obtain a second interleaved coded bit sequence
  • a modulating unit configured to modulate the first interleaved coded bit sequence into a first modulation symbol by using a first constellation, and map the first modulation symbol to a first group of subcarriers in a transmission bandwidth;
  • the modulating unit is further configured to: repeat the first interleaved coded bit sequence, modulate the repeated first interleaved coded bit sequence into a second modulation symbol by using a second constellation, and map the second modulation symbol a second set of subcarriers into the transmission bandwidth;
  • the modulating unit is further configured to: modulate the second interleaved coded bit sequence into a third modulation symbol by using the first constellation, and map the third modulation symbol to a third of the transmission bandwidth Group of subcarriers;
  • the modulating unit is further configured to: repeat the second interleaved coded bit sequence, modulate the repeated second interleaved coded bit sequence into a fourth modulation symbol by using the second constellation, and perform the fourth modulation The symbol is mapped to a fourth set of subcarriers in the transmission bandwidth.
  • the first group of subcarriers is a first half subcarrier of an odd subcarrier in the transmission bandwidth
  • the second group of subcarriers is the transmission zone The latter half of the subcarriers of the odd subcarriers
  • the third group of subcarriers is a first half of the even subcarriers of the transmission bandwidth
  • the fourth group of subcarriers is a second half of the even subcarriers of the transmission bandwidth.
  • the modulating unit is configured to: modulate the first interleaved coded bit sequence after the bit position is modulated into the first modulation symbol by using a first constellation; and repeat the bit interleave bit sequence after the bit position is repeatedly changed And modulating, by the second constellation diagram, the first interleaved coded bit sequence after the repeated bit position is modulated into the second modulation symbol.
  • the modulating unit is further configured to: perform the first modulation a symbol, the second modulation symbol, the third modulation symbol, and the fourth modulation symbol are inverse fast Fourier transform, and a cyclic prefix is added to obtain an orthogonal frequency division multiplexing OFDM symbol;
  • the transmitting end further includes a sending unit, configured to send the OFDM symbol.
  • a tenth aspect provides a receiving end, which is characterized by comprising:
  • An acquiring unit configured to acquire an OFDM symbol within a transmission bandwidth sent by the transmitting end
  • a parsing unit configured to parse the OFDM symbol to obtain a first interleaved encoded bit sequence and a second interleaved encoded bit sequence
  • a first deinterleaver configured to perform deinterleave processing on the first interleaved coded bit sequence to obtain an odd bit sequence
  • a second deinterleaver configured to perform deinterleave processing on the second interleaved coded bit sequence to obtain an even bit sequence
  • a decoding unit configured to recombine the odd bit sequence and the even bit sequence, and obtain valid information bits by channel decoding.
  • the parsing unit is specifically configured to:
  • the first group of subcarriers is the first half of the subcarriers of the odd subcarriers
  • the second group of subcarriers is the second half of the subcarriers of the odd subcarriers
  • the third group of subcarriers Is the first half of the subcarriers of the even subcarriers in the transmission bandwidth
  • the fourth group of subcarriers is the second half of the subcarriers of the even subcarriers
  • the transmitting end performs channel coding on the N information bits to obtain a coded bit sequence;
  • the M 2 bits are modulated by a third constellation and mapped to a third group of subcarriers in the transmission bandwidth.
  • the present invention is only The partial bits in the encoded bit sequence are repeatedly transmitted. Therefore, the number of bits in the encoded bit sequence obtained by the existing DCM technique is less than M, that is, the present invention can adopt a lower code rate versus N information.
  • the bits are encoded such that more redundant bits are included in the encoded bit sequence, thereby improving the error correction and error detection capabilities of the receiving end, and obtaining coding gain.
  • FIG. 1 is a flowchart of processing information bits by a conventional DCM technology provided by the present invention
  • FIG. 2 is a schematic flowchart of a code modulation method according to an embodiment of the present invention.
  • FIG. 3 is a schematic flowchart diagram of another code modulation method according to an embodiment of the present invention.
  • FIG. 4 is a flowchart of processing an information bit by a transmitting end according to an embodiment of the present invention
  • FIG. 5 is a flowchart of a demodulation method according to an embodiment of the present invention.
  • FIG. 6 is a flowchart of processing an OFDM symbol by a receiving end according to an embodiment of the present invention.
  • FIG. 7 is a schematic flowchart diagram of still another coding and modulation method according to an embodiment of the present invention.
  • FIG. 8 is a schematic flowchart diagram of still another coding and modulation method according to an embodiment of the present invention.
  • FIG. 9 is a flowchart of another method for processing information bits by a transmitting end according to an embodiment of the present invention.
  • FIG. 10 is a flowchart of another demodulation method according to an embodiment of the present invention.
  • FIG. 11 is a flowchart of another method for processing an OFDM symbol by a receiving end according to an embodiment of the present invention.
  • FIG. 12 is a schematic structural diagram of a transmitting end according to an embodiment of the present invention.
  • FIG. 13 is a schematic structural diagram of a receiving end according to an embodiment of the present invention.
  • FIG. 14 is a schematic structural diagram of another transmitting end according to an embodiment of the present invention.
  • FIG. 15 is a schematic structural diagram of another receiving end according to an embodiment of the present invention.
  • the 802.11 standard protocol specifies a plurality of modulation and coding schemes, including MCS0 to MCS5 as shown in Table 1 below.
  • MCS2 adopts a code rate of 1/2, that is, 2N information bits can be output for the input N information bits. And the MCS2 adopts a QPSK modulation method, which can map 2 bits to one modulation symbol and map the modulation symbol to one subcarrier.
  • the existing DCM technology is only used to improve the bit transmission capability in the MCS2 modulation mode, and does not consider how to improve the coding gain of the coded bit sequence transmitted by the transmitting end, the coding gain and the coding.
  • the number of redundant bits in the bit sequence is related to a code modulation and demodulation method and apparatus provided by the embodiments of the present invention, which can improve the coding gain of the bit sequence transmitted by the transmitting end while obtaining diversity and gain.
  • An embodiment of the present invention provides a coding and modulation method, where an execution body of the method is a transmitting end of an OFDM symbol, as shown in FIG. 2, the method includes:
  • the transmitting end performs channel coding on the N information bits to obtain an encoded bit sequence.
  • the encoded bit sequence includes M bits, N is a positive integer greater than 1, and M is a positive integer greater than N.
  • the transmitting end determines the coded bit sequence for the repeated transmission of M 1 and M bit is not used for repeat transmission of two bits.
  • the transmitting end may select M 1 bits in the odd bits A 1 A 2 A 3 ... A N for repeated transmission and determine the remaining in the encoded bit sequence M 2 bits are not used for repeated transmission; alternatively, the transmitting end selects M 1 bits for repeated transmission in even bits B 1 B 2 B 3 . . . B N and determines the remaining M in the encoded bit sequence 2 bits are not used for repeated transmission.
  • the transmitter uses the first interleaver for interleaving bits M 1, to obtain a first interleaved coded bit sequence, using a first constellation and a first interleaving the coded bit sequence modulating a first modulation symbol, and The first modulation symbol is mapped to a first set of subcarriers in a transmission bandwidth.
  • the transmitting end repeats the first interleaved coded bit sequence, modulates the repeated first interleaved coded bit sequence into a second modulation symbol by using a second constellation, and maps the second modulation symbol to a transmission bandwidth.
  • the second set of subcarriers The second set of subcarriers.
  • the transmitting end interleaves the M 2 bits by using a second interleaver to obtain a second interleaved coded bit sequence, and modulates the second interleaved coded bit sequence into a third modulation symbol by using a third constellation, and The third modulation symbol is mapped to a third set of subcarriers in the transmission bandwidth.
  • the interleaving manner used by the first interleaver and the second interleaver may be the same.
  • the first constellation, the second constellation, and the third constellation may belong to different constellations of the same modulation mode.
  • the first constellation diagram, the second constellation diagram, and the third constellation diagram adopt the same modulation order ⁇ , wherein the modulation order is the number of bits transmitted by one modulation symbol.
  • the first group of subcarriers is a pre-M 1 / ⁇ subcarriers in the transmission bandwidth
  • the second group of subcarriers is a post M 1 / in the transmission bandwidth.
  • ⁇ subcarriers, the third group of subcarriers being M 2 / ⁇ subcarriers remaining in the transmission bandwidth.
  • the interval between the first group of subcarriers and the second group of subcarriers is the largest, which is beneficial to the diversity and gain obtained by the receiving end.
  • the third set of subcarriers for each of (2M 1 + M 2) / c subcarriers in M 2 / c sub-carriers in the transmission bandwidth wherein, c is the greatest common divisor of 2M 1 and M 2 ; the first group of subcarriers is the first half of the remaining subcarriers in the transmission bandwidth, and the second group of subcarriers is the latter half of the remaining subcarriers Carrier.
  • the transmission bandwidth transmitted by the transmitting end carries M 1 bits of repeated transmission, and M 2 bits of unrepeated, so that the total number of bits transmitted at the transmitting end is the same, and the input information bits are
  • the existing DCM technology since the existing DCM technology repeatedly transmits all the bits in the encoded bit sequence, and the present invention only repeats the transmission of some bits in the encoded bit sequence, the existing DCM technology is encoded.
  • the number of bits in the encoded bit sequence is less than M, that is, the present invention can encode N information bits with a lower code rate, so that more redundant bits are included in the encoded bit sequence, thereby improving
  • the error correction and error detection capability at the receiving end obtains the coding gain.
  • the present invention reduces the code rate adopted by each modulation and coding scheme in the existing standard, that is, for the original modulation coding.
  • the original code rate n/m adopted by the scheme has a relationship that N/M is less than n/m, and the N/M is the code rate adopted by the transmitting end of the present invention.
  • the total amount of bits that can be transmitted in the transmission bandwidth is 2 Nm/n, and if the total amount of bits transmitted by the present invention is constant, Then, after channel coding the N information bits to obtain M bits, the number M 1 of bits used for repeated transmission is equal to 2Nm/nM, and the number M2 of bits not used for repeated transmission is equal to 2M-2Nm/n, so that The ratio of the number of subcarriers included in the first group of subcarriers to the number of subcarriers included in the second group of subcarriers, and the ratio of the number of subcarriers included in the third group of subcarriers is (2m-Mn)/(Mn -m).
  • step S201 for X 1 x 2 x 3 ... x N , a total of N information bits, the transmitting end encodes the N information bits by using a code rate of 1/2, and the obtained encoded information is obtained.
  • the bit sequence is A 1 B 1 A 2 B 2 A 3 B 3 ... A N B N .
  • the transmitting end determines that the M1 bits used for repeated transmission in the bit sequence and the M 2 bits that are not used for repeated transmission specifically include: in the odd bits A 1 A 2 A 3 ... A N Selecting M 1 bits for repeated transmission, determining that the remaining M 2 bits in the encoded bit sequence are not used for repeated transmission; or selecting M 1 bits in even bits B 1 B 2 B 3 . . . B N For repeated transmissions, it is determined that the remaining M 2 bits in the encoded bit sequence are not used for repeated transmission.
  • the transmitting end selects two odd bits or two even bits for every 6 bits for repetition Transmission, the remaining 4 bits are not used for repeated transmission.
  • Manner 1 The transmitting end selects the first two odd bits in each of the 6 bits of the encoded bit sequence A 1 B 1 A 2 B 2 A 3 B 3 ... A N B N for repeated transmission, that is, for repetition
  • the transmitted bits are A 1 A 2 A 4 A 5 A 7 A 8 ...
  • the bits not used for repeated transmission are B 1 B 2 A 3 B 3 B 4 B 5 A 6 B 6 B 7 B 8 A 9 B 9 ....
  • the transmitting end selects the first and last two odd bits in each of the 6 bits of the encoded bit sequence A 1 B 1 A 2 B 2 A 3 B 3 ... A N B N for repeated transmission, that is, for repetition
  • the transmitted bits are A 1 A 3 A 4 A 6 A 7 A 9 ...
  • the bits not used for repeated transmission are B 1 A 2 B 2 B 3 B 4 A 5 B 5 B 6 B 7 A 7 B 8 B 9 ....
  • Manner 3 The transmitting end selects the middle two odd bits in each of the 6 bits of the encoded bit sequence A 1 B 1 A 2 B 2 A 3 B 3 ... A N B N for repeated transmission, that is, for repetition
  • the transmitted bits are A 2 A 3 A 5 A 6 A 8 A 9 ...
  • the bits not used for repeated transmission are A 1 B 1 B 2 B 3 A 4 B 4 B 5 B 6 A 7 B 7 B 8 B 9 ....
  • the transmitting end may also select the first two even bits in every 6 bits of the encoded bit sequence A 1 B 1 A 2 B 2 A 3 B 3 ... A N B N , or The first and last even two bits, or the middle two even bits are used for repeated transmission.
  • a N B N selects the first two bits out of every 6 bits, ie the first odd bit and the first even bit are used for repeated transmission, or The first odd bit or the second even bit is selected for repeated transmission, which is not limited by the present invention.
  • the transmitting end may also select bits for repeated transmission by other means, which is not limited by the present invention.
  • the ratio between the number of subcarriers included in the subcarrier and the number of subcarriers included in the second group of subcarriers, and the number of subcarriers included in the third group of subcarriers is specifically 2 (mn) / (2n - m) .
  • the transmitting end can divide all subcarriers in the transmission bandwidth into 2(mn)+(2n-m) subbands, wherein each subband includes the same number of subcarriers, and the first half subband of the odd subbands in the 2(mn)+(2n-m) subbands Dividing into the first group of subcarriers, dividing the second half of the subbands of the odd subbands in the 2(mn)+(2n-m) subbands into the second group of subcarriers, the 2(mn)+( The remaining subbands of 2n-m) subbands are divided into the third group of subcarriers.
  • the transmitting end divides all subcarriers in the transmission bandwidth into 4 subbands, where each subband includes the same number of subcarriers, for example, in the transmission bandwidth. All subcarriers are f 1 , f 2 , f 3 , ..., f 12 , then the first subband of the 4 subbands is f 1 , f 2 , f 3 , and the second subband is f 4 , f 5 , f 6 , the third sub-band is f 7 , f 8 , f 9 , and the fourth sub-band is f 10 , f 11 , f 12 , and further, the transmitting end of the first sub-band of the four sub-bands As the first group of subcarriers, the third subband is used as the second group of subcarriers, and the second subband and the third subband are used as the third group of subcarriers.
  • the transmitting end divides all subcarriers in the transmission bandwidth into three subbands, wherein each subband includes the same number of subcarriers, for example, in the transmission bandwidth. All subcarriers are f 1 , f 2 , f 3 , ..., f 12 , then the first subband of the 3 subbands is f 1 , f 2 , f 3 , f 4 , and the second subband is f 5 , f 6 , f 7 , f 8 , the third sub-band is f 9 , f 10 , f 11 , f 12 , further, the transmitting end uses the first sub-band of the three sub-bands as the first group
  • the subcarriers have a third subband as the second group of subcarriers and a second subband as the third group of subcarriers.
  • the transmitting end divides all subcarriers in the transmission bandwidth into 8 subbands, where each subband includes the same number of subcarriers
  • the transmitting end may The first subband and the third subband of the 8 subbands are divided into the first group of subcarriers, and the fifth subband and the seventh subband of the 8 subbands are divided into the second group of subcarriers, The second subband of the 8 subbands, the fourth subband, the sixth subband and the eighth subband are divided into the third group of subcarriers.
  • the transmitting end may also be every Nm/(Mn-Nm) in the transmission bandwidth. Dividing one subcarrier into a third group of subcarriers, and dividing a first half of the remaining subcarriers in the transmission bandwidth into the first group of subcarriers, and dividing the second half of the subcarriers into the second group Subcarrier.
  • the transmitting end divides one subcarrier into the third group of subcarriers in every two subcarriers in the transmission bandwidth, for example, If all the subcarriers in the transmission bandwidth are f 1 , f 2 , f 3 , . . . , f 12 , the transmitting end can divide the subcarriers f 2 , f 4 , f 6 , f 8 , f 10 , f 12 into the first subcarriers.
  • the three sets of subcarriers divide the subcarriers f 1 , f 3 , f 5 into a first group of subcarriers, and divide the subcarriers f 7 , f 9 , f 11 into a second group of subcarriers.
  • the transmitting end divides one subcarrier into the third group of subcarriers in every three subcarriers in the transmission bandwidth, for example, the transmission bandwidth. All the subcarriers in the medium are f 1 , f 2 , f 3 , ..., f 12 , then the transmitting end can divide the subcarriers f 3 , f 6 , f 9 , f 12 into a third group of subcarriers, and the subcarriers f 1 , f 2 , f 4 , f 5 are divided into a first group of subcarriers, and subcarriers f 7 , f 8 , f 10 , f 11 are divided into second group subcarriers.
  • the transmitting end divides one subcarrier into the third group of subcarriers in every three subcarriers in the transmission bandwidth, for example, the transmission bandwidth. All the subcarriers in the medium are f 1 , f 2 , f 3 , ..., f 16 , then the transmitting end can divide the subcarriers f 4 , f 8 , f 12 , f 16 into a third group of subcarriers, and the subcarriers f 1 , f 2 , f 3 , f 5 , f 6 , f 7 are divided into first group of subcarriers, and subcarriers f 9 , f 10 , f 11 , f 13 , f 14 , f 15 are divided into second groups Subcarrier.
  • the transmitting end determines the bits for repeated transmission for different original code rates, and the manner of grouping the subcarriers in the transmission bandwidth.
  • the transmission is performed.
  • the code rate N/M of the channel coding may have other values, which are not enumerated here.
  • the transmitting end may further perform an inverse fast Fourier transform on the modulation symbols mapped to the first group of subcarriers, the second group of subcarriers, and the third group of subcarriers, and add a cyclic prefix to obtain
  • the OFDM symbols are orthogonally frequency division multiplexed and transmitted.
  • the existing DCM technology performs channel coding by 3/4 code rate for 6 information bits, and obtains an encoded bit sequence including 8 bits, wherein there are two redundant bits among the 8 bits, and the 8 coded bits are repeatedly transmitted. Therefore, the total amount of bits transmitted by the transmitting end is 16, and after receiving the two sets of coded bit sequences repeatedly transmitted by the transmitting end, the two sets of coded bit sequences can be combined. Obtaining the diversity and gain in the frequency domain;
  • the code modulation method provided by the embodiment of the present invention obtains a coded bit sequence including 12 bits for channel coding by using a 1/2 code rate for six information bits, wherein there are 6 redundant bits in the 12 bits.
  • the remaining bits, and 4 bits of the 12 bits are repeatedly transmitted, and the remaining 8 bits are not used for repeated transmission, so that the receiving end can obtain the diversity in the frequency domain after receiving the repeated transmission of another bit by the transmitting end.
  • Gain in addition, since the redundant bits included in the coded bits are more, thereby improving the error correction and error detection capability of the receiving end, the coding gain is obtained.
  • Embodiment 1 of the present invention describes an existing scheme for improving MCS2 by using DCM technology, and illustrates that the embodiment of the present invention adopts a 1/2 code rate.
  • the technical effect that the embodiment of the present invention can obtain when N/M 1/2, and the 16-QAM modulation mode.
  • MCS2 can obtain 4N after channel coding.
  • the transmitting end performs convolutional coding of N information bits with a coding rate of 1/2 to obtain an encoded bit sequence.
  • the encoded bit sequence includes 2N bits, and N is a positive integer greater than 1.
  • the transmitting end determines 2N/3 bits in the encoded bit sequence for repeated transmission and 4N/3 bits not used for repeated transmission.
  • step S302 the transmitting end determines 2N/3 bits in the odd or even bits of the encoded bit sequence for repeated transmission, and determines that the remaining 4N/3 bits are not used for repeated transmission.
  • the transmitting end interleaves the 2N/3 bits by using a first interleaver to obtain a first interleaved coded bit sequence, and composing the first interlace by using a first constellation diagram of a 16-QAM modulation mode.
  • the code bit sequence is modulated into a first modulation symbol and the first modulation symbol is mapped to a first set of subcarriers in the transmission bandwidth.
  • the transmitting end repeats the first interleaved coded bit sequence, and modulates the repeated first interleaved coded bit sequence into a second modulation symbol by using a second constellation of the 16-QAM modulation mode, and the second modulation symbol is used. Maps to a second set of subcarriers in the transmission bandwidth.
  • the transmitting end interleaves the 4N/3 bits by using a second interleaver to obtain a second interleaved coded bit sequence, and modulates the second interleaved coded bit sequence into a third constellation diagram of a 16-QAM modulation mode. a third modulation symbol and mapping the third modulation symbol to a third set of subcarriers in the transmission bandwidth.
  • the total amount of bits transmitted by the transmitting end is also 8N/3, so that when the input information bits are all N and the total output information bits are 8N/3,
  • the invention adopts a lower code rate, so that the number of bits included in the encoded bit sequence of the embodiment of the present invention is larger than the existing DCM technology, and therefore, the embodiment of the present invention improves the coding gain.
  • each of the constellation points in the 16-QAM modulation scheme can be mapped to a modulation symbol on one subcarrier, and the number of bits transmitted is four.
  • the transmitting end transmits the first interleaved coded bit sequence to the first modulation symbol before using the first constellation of the 16-QAM modulation mode.
  • All subcarriers in the bandwidth are divided into 4 subbands, each subband includes the same number of subcarriers, and the first group of subcarriers is the first subband of the 4 subbands, and the second group of subcarriers is The third sub-band of the 4 sub-bands is the second sub-band and the fourth sub-band of the 4 sub-bands.
  • the transmitting end may further perform the transmission before the N/3 bits are modulated into the first modulation symbol by using the first constellation of the 16-QAM modulation mode. Dividing one subcarrier into the third group of subcarriers in each of the two subcarriers in the bandwidth, and dividing the first half of the remaining subcarriers in the transmission bandwidth into the first group of subcarriers, and the second half of the subcarriers Divided into the second group of subcarriers.
  • FIG. 4 is a flowchart of processing information bits according to an embodiment of the present invention, as shown in FIG. 4 . As shown, each of the method steps shown in FIG. 3 is visually displayed in FIG. 4. Compared with FIG. 4 and FIG. 1, a code modulation method and an existing DCM technology provided by the embodiments of the present invention can be more directly embodied. The difference.
  • the transmitting end encodes N information bits through a channel to obtain an encoded bit sequence including 2N bits, and the transmitting end encodes the encoded bit sequence by bit grouping. Divided into a first bit sequence comprising 2N/3 bits, and a second bit sequence comprising 4N/3 bits, wherein the 2N/3 bits are used for repeated transmission, and the 4N/3 bits are not used for repeated transmission .
  • the transmitting end may select one of every 3 bits of the encoded bit sequence for repeated transmission, the remaining two are not used for repeated transmission, or may select two for every 6 bits of the encoded bit sequence for repetition. For the transmission, the remaining 4 are not used for the repeated transmission, which is not limited by the embodiment of the present invention.
  • the transmitting end may be in the encoded bit sequence A 1 B 1 A 2 B 2 A 3 B 3 ...
  • the first two odd bits are selected for every 6 bits of A N B N , or two odd bits at the beginning and the end, or two odd bits are used for repeated transmission, and the remaining bits are not used for repeated transmission.
  • the transmitting end performs interleaving processing on the first bit sequence by using the first interleaver, and repeats the first bit sequence after the interleaving process to obtain two sets of identical third bit sequences and fourth bit sequences, which will The second bit sequence is interleaved by the second interleaver to obtain a fifth bit sequence.
  • the transmitting end determines a first group of subcarriers including N/12 subcarriers in the transmission bandwidth, a second group of subcarriers including N/12 subcarriers, and a third group of subcarriers including N/6 subcarriers .
  • the following example illustrates how the transmitting end divides the first group of subcarriers, the second group of subcarriers, and the third group of subcarriers.
  • the transmitting end divides all subcarriers in the transmission bandwidth into 4 subbands, and the transmitting end divides all subcarriers in the transmission bandwidth into 4 subbands, where each subband includes the same number of subcarriers. For example, if all subcarriers in the transmission bandwidth are f 1 , f 2 , f 3 , . . .
  • the first subband of the 4 subbands is f 1 , f 2 , f 3 , and the second sub
  • the band is f 4 , f 5 , f 6
  • the third sub-band is f 7 , f 8 , f 9
  • the fourth sub-band is f 10 , f 11 , f 12
  • the transmitting end is the 4 sub-bands
  • the first subband in the group serves as the first group of subcarriers, the third subband as the second group of subcarriers, and the second subband and the third subband as the third group of subcarriers.
  • the transmitting end divides one subcarrier into the third group of subcarriers in every two subcarriers in the transmission bandwidth, for example, all subcarriers in the transmission bandwidth are f 1 , f 2 , f 3 ,... , f 12
  • the transmitter may divide the subcarriers f 2 , f 4 , f 6 , f 8 , f 10 , f 12 into a third group of subcarriers, and divide the subcarriers f 1 , f 3 , f 5 into The first set of subcarriers divides the subcarriers f 7 , f 9 , f 11 into a second set of subcarriers.
  • the transmitting end modulates the third bit sequence into a first modulation symbol by using a first constellation of 16-QAM, and maps the first modulation symbol to the first group of subcarriers, and adopts a 16-QAM
  • the second constellation map modulates the fourth bit sequence into a second modulation symbol, and maps the second modulation symbol to the second group of subcarriers, and modulates the fifth bit sequence into a third constellation by using a third constellation of 16-QAM Transmitting a third modulation symbol to the first group of subcarriers, performing an inverse fast Fourier transform on the first modulation symbol, the second modulation symbol, and adding a cyclic prefix , an OFDM symbol is obtained, and the OFDM symbol is transmitted.
  • the receiving end can parse the third bit sequence, the fourth bit sequence and the fifth bit sequence, and combine the third bit sequence and the fourth bit sequence to obtain
  • the diversity and gain are combined, and since the 1/2 code rate is compared with the 3/4 code rate, more redundant bits are included in the coded bit sequence, thereby improving the error correction and error detection capability of the receiving end, and obtaining the coding gain.
  • An embodiment of the present invention provides a coding and demodulation method, where an execution body of the method is a receiving end of an OFDM symbol, which is used to modulate the code modulation method provided by Embodiment 1 of the present invention.
  • the OFDM symbol is demodulated, as shown in FIG. 5, and includes:
  • the receiving end acquires an OFDM symbol within a transmission bandwidth sent by the transmitting end, where the transmission bandwidth includes a first group of subcarriers, a second group of subcarriers, and a third group of subcarriers.
  • the receiving end parses the OFDM symbol to obtain a first modulation symbol on the first group of subcarriers, a second modulation symbol on the second group of subcarriers, and a third modulation symbol on the third group of subcarriers.
  • the terminal receives the first modulation symbol and the second modulation symbols joint demodulation according to the first constellation map and second constellation map to obtain M 1 bit, according to a third de-third modulation symbol of the constellation M 2 bits are obtained.
  • the receiving end reassembles the M 1 bit and the M 2 bit, and obtains the N information bits by channel decoding.
  • the existing DCM technique repeats all the bits in the encoded bit sequence, and the present invention only encodes Some bits in the bit sequence are repeatedly transmitted. Therefore, the number of bits in the encoded bit sequence obtained by the existing DCM technique is less than M, that is, the present invention can perform N information bits with a lower code rate.
  • the coding makes more redundant bits included in the encoded bit sequence, thereby improving the error correction and error detection capability of the receiving end and obtaining the coding gain.
  • FIG. 6 is a flowchart of processing a OFDM symbol by a receiving end according to an embodiment of the present invention.
  • the receiving end removes a CP from each received OFDM symbol, and then passes the fast Fuli.
  • the leaf transform (English full name: Fast Fourier Transformation, FFT for short) transforms the signal into the frequency domain, and then extracts the first group of subcarriers after channel equalization, the second group of subcarriers and the third group of subcarriers First to third modulation symbols, combined with the first constellation diagram and the second constellation diagram, jointly demodulating the first modulation symbol and the second modulation symbol, and then passing through the first deinterleaver; using the third constellation pair
  • the third modulation symbol is demodulated and then passed through a second deinterleaver, wherein the first deinterleaver and the second deinterleaver respectively respectively interleave M 1 bits with the transmitting end and the pair A second interleaver in which M 2 bits are interleaved corresponds to each other.
  • An embodiment of the present invention provides a method for coding modulation.
  • the execution body of the method is a transmitting end of an OFDM symbol. As shown in FIG. 7, the method includes:
  • the transmitting end performs channel coding on multiple information bits to obtain an encoded bit sequence.
  • the transmitting end performs interleaving processing on the odd bit sequence included in the encoded bit sequence according to the first interleaver to obtain a first interleaved encoded bit sequence.
  • the transmitting end performs interleaving processing on the even bit sequence included in the encoded bit sequence according to the second interleaver to obtain a second interleaved encoded bit sequence.
  • the transmitting end modulates the first interleaved coded bit sequence into a first group of subcarriers in a transmission bandwidth by using a first constellation.
  • the transmitting end repeats the first interleaved coded bit sequence, and the repeated first interleaved coded bit sequence is modulated by the second constellation and then mapped to the second group of subcarriers in the transmission bandwidth.
  • the transmitting end modulates the second interleaved coded bit sequence into a third group of subcarriers in the transmission bandwidth by using a first constellation.
  • the transmitting end repeats the second interleaved coded bit sequence, and the repeated second interleaved coded bit sequence is modulated by the second constellation and then mapped to the fourth group of subcarriers in the transmission bandwidth.
  • the first interleaver is different from the second interleaver, so that the transmitting end divides the encoded bit sequence into an odd bit sequence and an even bit sequence according to an arrangement order.
  • interleaving the odd bit sequence and the even bit sequence respectively by using different interleavers and the present invention can pass the adjacent two bits in the encoded bit sequence by using the same interleaver for interleaving the encoded bit sequence.
  • the constellation map is mapped to two subcarriers that are further apart, so that the distribution of the encoded bit sequence in the transmission bandwidth is more dispersed, which is advantageous for the receiving end to obtain diversity and gain.
  • the transmitting end swaps the first n bits and the last m bits in the first interleaved coded bit sequence.
  • n and m are both positive integers greater than 1
  • n + m N
  • N is the number of bits included in the first interleaved coded bit sequence
  • the transmitting end uses the first constellation diagram to change the bit position
  • the first interleaved coded bit sequence is modulated into the first modulation symbol, and the first interleaved coded bit sequence after the bit position is repeatedly switched, and the first interlace code after the repeated bit position is repeated by using the second constellation picture
  • the bit sequence is modulated into the second modulation symbol, wherein the first interleaver and the second interleaver may be identical.
  • the first interleaved coded bit sequence is A 0 A 1 A 2 A 3 . . . A 47
  • the second interleaved coded bit sequence is B 0 B 1 B 2 B 3 . . . B 47
  • the transmitting end will The first 24 bits in the first interleaved coded bit sequence A 0 A 1 A 2 ... A 23 and the last 24 bits A 24 A 25 A 26 ... A 47 swap position, the first interleaved coded bit sequence after the swap position That is, A 24 A 25 A 26 ... A 47 A 0 A 1 A 2 ...
  • the transmitting end maps the first interleaved coded bit sequence after the swap position to the first constellation map a first set of subcarriers, repeating the first interleaved coded bit sequence after the swap position, and mapping the repeated first interleaved coded bit sequence to the second set of subcarriers by using the second constellation
  • the second interleaved coded bit sequence B 0 B 1 B 2 B 3 . . . B 47 is mapped to the third group of subcarriers by the third constellation, and the second interleaved coded bit sequence is repeated, and the fourth constellation is adopted.
  • the repeated second interleaved coded bit sequence is mapped to the fourth set of subcarriers.
  • the values of n and m may not be half of the number of bits included in the first interleaved coded bit sequence, for example, When the number of bits N included in the first interleaved coded bit sequence is an odd number, n may be equal to (2N-1)/2, and m may be equal to (2N+1)/2, which is not limited in the present invention.
  • the location of the first interleaved bit sequence is changed with the transmitting end, and the second interleaving bit sequence is unchanged, and the transmitting end may also perform position switching on the second interleaved bit sequence, and the first interleaved bit sequence is unchanged, and is no longer Narration.
  • the first subcarrier is a first half subcarrier of an odd subcarrier in the transmission bandwidth
  • the second subcarrier is a second half subcarrier of an odd subcarrier in the transmission bandwidth
  • the third subcarrier is The first half of the even subcarriers in the transmission bandwidth
  • the fourth subcarrier is the second half of the even subcarriers in the transmission bandwidth.
  • the transmission bandwidth of the transmitting end includes 48 subcarriers as f 1 , f 2 , f 3 , . . . , f 48 , and the transmitting end allocates subcarriers f 1 , f 3 , f 5 , . . . , f 47 to the first interleaved bit. a sequence in which the first half of the subcarriers f 1 , f 3 , f 5 , ..., f 47 , i.e., f 1 , f 3 , f 5 , ..., f 23 are used to transmit the first modulation symbol, One half of the subcarriers f 25 , f 27 , f 29 , .
  • the subcarriers f 2 , f 4 , f 6 , . . . , f 48 are allocated to the second interleaved bit sequence wherein the subcarrier f 2, f 4, f 6 , ..., f 48 of the first half of the subcarrier f 2, f 4, f 6 , ..., f 24, for transmitting the third modulation symbol, the sub-half Carriers f 26 , f 28 , f 30 , ..., f 48 are used to transmit the fourth modulation symbol.
  • the transmitting end performs inverse fast Fourier transform on the first modulation symbol, the second modulation symbol, the third modulation symbol, and the fourth modulation symbol, and adds a cyclic prefix to obtain an orthogonal frequency division multiplexing OFDM symbol. And transmitting the OFDM symbol.
  • the transmitting end performs convolutional coding with a coding rate of 1/2 for N information bits to obtain an encoded bit sequence.
  • the coded bit sequence includes 2N bits, and N is a positive integer greater than 1.
  • the transmitting end encodes the odd bit included in the encoded bit sequence according to the first interleaver. Performing interleaving processing on the sequence to obtain a first interleaved encoded bit sequence;
  • the transmitting end performs interleaving processing on the even bit sequence included in the encoded bit sequence according to the second interleaver to obtain a second interleaved encoded bit sequence.
  • the transmitting end modulates the first interleaved coded bit sequence into a first modulation symbol by using a first constellation of a 16-QAM modulation mode, and maps the first modulation symbol to a first group of subcarriers in a transmission bandwidth.
  • the transmitting end repeats the first interleaved coded bit sequence, and modulates the repeated first interleaved coded bit sequence into a second modulation symbol by using a second constellation of the 16-QAM modulation mode, and maps the second modulation symbol. a second set of subcarriers into the transmission bandwidth;
  • the transmitting end modulates the second interleaved coded bit sequence into a third modulation symbol by using the first constellation in a 16-QAM modulation mode, and maps the third modulation symbol to a third group in the transmission bandwidth.
  • the transmitting end repeats the second interleaved coded bit sequence, and the second constellation of the 16-QAM modulation mode modulates the repeated second interleaved coded bit sequence into a fourth modulation symbol, and the fourth modulation symbol is modulated. Mapping to a fourth set of subcarriers in the transmission bandwidth.
  • the transmitting end passes the N information bits through a convolutional encoder with a code rate of 1/2, and obtains the encoded bit sequence A 1 B 1 A. 2 B 2 A 3 B 3 ... A N B N , and divide the encoded bit sequence into two groups by parity bits, that is, divide the odd bit sequence A 1 A 2 A 3 ... A N of the encoded bit sequence into one Group, even bit sequence B 1 B 2 B 3 ...
  • the two sets of bit sequences are respectively interleaved by a first interleaver and a second interleaver, wherein the first interleaver and the The second interleaver may be two different interleavers to obtain a first interleaved coded bit sequence and a second interleaved coded bit sequence.
  • the first interleaver and the second interleaver may also use the same interlace.
  • the transmitting end transposes the bit position of the interleaving result of the odd bit sequence and the one of the even bit sequences to obtain the first interleaved coded bit sequence and the second interleaved coded bit sequence.
  • the transmitting end modulates the first interleaved coded bit sequence and the second interleaved coded bit sequence by using an existing DCM, that is, each group of sequences is repeatedly obtained to obtain two sets of the same sequence, and the two groups are The bit sequences are respectively modulated according to the same modulation mode, such as two different constellations of 16-QAM, to obtain the first to fourth modulation symbols, and map the first modulation symbols to the first half of the odd subcarriers in the transmission bandwidth.
  • the same modulation mode such as two different constellations of 16-QAM
  • the transmitting end transforms the first to fourth modulation symbols into the time domain by IFFT, and adds the CP to form an OFDM symbol.
  • the code rate adopted by MCS1 is 1/2
  • the modulation scheme adopted is QPSK.
  • the transmitting end will be modulated into a 16-QAM modulation symbol every 4 bits, and the adjacent 2 16-QAM symbols will be mapped to the adjacent 2 available subcarriers.
  • the 12 bits are modulated into three modulation symbols and mapped to three adjacent subcarriers, that is, A 0 A 8 A 16 A 24 , A 32 A 40 B 0 B 8 and B 16 B 24 B 32 B 40 will be mapped onto 3 adjacent subcarriers.
  • there are 2 pairs of adjacent coded bits for every 2 adjacent subcarriers on the 3 adjacent subcarriers namely A 0 B 0 , A 8 B 8 , A 32 B 32 and A 40 B 40 .
  • the odd bit sequence and the even bit sequence in the encoded bit sequence A 0 B 0 A 1 B 1 ... A 47 B 47 are respectively interleaved by the code modulation method provided by the present invention, and a set of interleaved bit sequences are respectively performed.
  • the first half of the bit sequence obtained by swapping the bit positions is:
  • the 12 bits are modulated into 3 modulation symbols and mapped to 3 adjacent subcarriers, namely A 0 A 12 A 24 A 36 , B 6 B 18 B 30 B 42 and A 13 A 1 A 37 A 25 will be mapped onto 3 adjacent subcarriers.
  • the modulation and coding scheme adopted by the embodiment of the present invention can obtain sufficient interleaving of the encoded bit sequence, which is advantageous for obtaining the diversity and gain of the receiving end.
  • An embodiment of the present invention provides a method for encoding and demodulating, where an execution body of the method is a receiving end of an OFDM symbol, and is used for demodulating an OFDM symbol modulated by the coding and modulation method provided by Embodiment 4 of the present invention, as shown in the figure. 10, including:
  • the receiving end acquires an OFDM symbol in a transmission bandwidth sent by the transmitting end.
  • S1002 The receiving end parses the OFDM symbol to obtain a first interleaved coded bit sequence and a second interleaved coded bit sequence.
  • the receiving end performs deinterleaving processing on the first interleaved coded bit sequence according to the first deinterleaver to obtain an odd bit sequence.
  • the receiving end performs deinterleaving processing on the second interleaved coded bit sequence according to the second deinterleaver to obtain an even bit sequence.
  • the first deinterleaver and the second deinterleaver respectively correspond to a first interleaver that interleaves the odd bit sequence at the transmitting end and a second interleaver that interleaves the even bit sequence, and the transmitting end pair
  • first interleaver that interleaves the odd bit sequence at the transmitting end
  • second interleaver that interleaves the even bit sequence
  • the receiving end reassembles the odd bit sequence and the even bit sequence, and obtain valid information bits by channel decoding.
  • the transmitting end divides the coded bit sequence into an odd bit sequence and an even bit sequence according to the arrangement order, and respectively interleaves the odd bit sequence and the even bit sequence by using different interleavers. Or, the same interleaver is used for interleaving, and the position of one of the interleaving results is changed, and the same interleaver is used for interleaving.
  • the receiving end may be at a farther interval. Sub-load The two adjacent bits in the encoded bit sequence are acquired on the wave, which improves the diversity and gain.
  • FIG. 11 is a flowchart of processing a OFDM symbol by a receiving end according to an embodiment of the present invention.
  • the receiving end After receiving the OFDM symbol sent by the transmitting end, the receiving end first removes the CP, and then transforms the signal into the frequency domain by using an FFT. After channel equalization, corresponding first to fourth modulation symbols are extracted according to the parity subcarrier, and for the first modulation symbol and the second modulation symbol, the transmitting end is combined with the first constellation and the second constellation to perform demodulation.
  • the first interleaved bit sequence in combination with the first constellation diagram and the second constellation diagram, jointly demodulates the third modulation symbol and the fourth modulation symbol to obtain a second interleaved bit sequence, and passes the first deinterleaver and the first
  • the second deinterleaver deinterleaves the first interleaved bit sequence and the second interleaved bit sequence to obtain the odd bit sequence and the even bit sequence, and obtains the encoded bit sequence by recombination, and finally, the recombined
  • the encoded bit sequence is decoded by the decoder to obtain valid information bits transmitted by the transmitting end.
  • the present invention provides a transmitting end 12 for implementing the modulation method provided by Embodiment 1 and Embodiment 2 of the present invention. As shown in FIG. 12, the transmitting end 12 includes:
  • the channel encoder 121 is configured to perform channel coding on the N information bits to obtain an encoded bit sequence; the coded bit sequence includes M bits, N is a positive integer greater than 1, and M is a positive integer greater than N;
  • a first interleaver 123 configured to interleave the M 1 bits to obtain a first interleaved coded bit sequence
  • the modulating unit 124 is configured to modulate the first interleaved coded bit sequence into a first modulation symbol by using a first constellation, and map the first modulation symbol to a first group of subcarriers in a transmission bandwidth;
  • the modulating unit 124 is further configured to: repeat the first interleaved coded bit sequence, modulate the repeated first interleaved coded bit sequence into a second modulation symbol by using a second constellation, and map the second modulation symbol to a transmission bandwidth a second set of subcarriers;
  • a second interleaver 125 configured to interleave the M 2 bits to obtain a second interleaved coded bit sequence
  • the modulating unit 124 is further configured to modulate the second interleaved coded bit sequence into a third modulation symbol by using a third constellation, and map the third modulation symbol to a third group of subcarriers in the transmission bandwidth.
  • the first constellation diagram, the second constellation diagram, and the third constellation diagram adopt the same modulation order ⁇ , where the modulation order is the number of bits transmitted by one modulation symbol.
  • the first group of subcarriers is the first M 1 / ⁇ subcarriers in the transmission bandwidth
  • the second group of subcarriers is the last M 1 / ⁇ subcarriers in the transmission bandwidth
  • the third group of subcarriers is the transmission bandwidth. The remaining M 2 / ⁇ subcarriers.
  • the third set of subcarriers that M 2 / c per sub-carriers (2M 1 + M 2) / c sub-carriers in the transmission bandwidth; wherein, c is the greatest common divisor of 2M 1 and M 2 ;
  • the first group of subcarriers is the first half of the remaining subcarriers in the transmission bandwidth, and the second group of subcarriers is the latter half of the remaining subcarriers.
  • the bit grouping unit is specifically used for:
  • M 1 bits are selected for repeated transmission, and it is determined that the remaining M 2 bits in the encoded bit sequence are not used for repeated transmission.
  • the modulating unit 124 is further configured to: perform inverse fast Fourier transform on the first modulation symbol, the second modulation symbol, and the third modulation symbol, and add a cyclic prefix to obtain an orthogonal frequency division multiplexing OFDM symbol. ;
  • the transmitting end also includes a transmitting unit 126 for transmitting the OFDM symbol.
  • the implementation of the present invention provides a receiving end 13 for implementing the demodulation method provided in Embodiment 3 of the present invention. As shown in FIG. 13, the receiving end 13 includes:
  • the acquiring unit 131 is configured to acquire an OFDM symbol within a transmission bandwidth sent by the transmitting end, where the transmission bandwidth includes a first group of subcarriers, a second group of subcarriers, and a third group of subcarriers;
  • the parsing unit 132 is configured to parse the OFDM symbol to obtain a first modulation symbol on the first group of subcarriers, a second modulation symbol on the second group of subcarriers, and a third modulation symbol on the third group of subcarriers ;
  • the decoding unit 134 is configured to recombine the M 1 bits and the M 2 bits, and obtain the N information bits by channel decoding.
  • the implementation of the present invention provides a transmitting end 14 for implementing the modulation method provided by Embodiment 4 and Embodiment 5 of the present invention.
  • the receiving end 14 includes:
  • a channel encoder 141 configured to perform channel coding on multiple information bits to obtain an encoded bit sequence
  • a first interleaver 142 configured to perform interleaving processing on the odd bit sequence included in the encoded bit sequence to obtain a first interleaved coded bit sequence
  • a second interleaver 143 configured to perform interleaving processing on the even bit sequence included in the encoded bit sequence to obtain a second interleaved encoded bit sequence
  • the modulating unit 144 is configured to modulate the first interleaved coded bit sequence into a first modulation symbol by using a first constellation, and map the first modulation symbol to a first group of subcarriers in a transmission bandwidth;
  • the modulating unit 144 is further configured to: repeat the first interleaved coded bit sequence, modulate the repeated first interleaved coded bit sequence into a second modulation symbol by using a second constellation, and map the second modulation symbol to the transmission a second set of subcarriers in the bandwidth;
  • the modulating unit 144 is further configured to: modulate the second interleaved coded bit sequence into a third modulation symbol by using the first constellation, and map the third modulation symbol to a third group of subcarriers in the transmission bandwidth;
  • the modulating unit 144 is further configured to: repeat the second interleaved coded bit sequence, modulate the repeated second interleaved coded bit sequence into a fourth modulation symbol by using the second constellation, and map the fourth modulation symbol to the The fourth set of subcarriers in the transmission bandwidth.
  • the first group of subcarriers is a first half of the subcarriers of the odd subcarriers in the transmission bandwidth
  • the second group of subcarriers is a second half of the subcarriers of the odd subcarriers in the transmission bandwidth
  • the third group of subcarriers is the first half of the even subcarriers in the transmission bandwidth
  • the fourth group of subcarriers is the latter half of the even subcarriers in the transmission bandwidth.
  • the modulating unit 144 is configured to: modulate the first interleaved coded bit sequence after the bit position is modulated into the first modulation symbol by using a first constellation; and repeat the bit interleave bit sequence after the bit position is repeated, The second constellation will repeat the first interlace after the bit position is changed The coded bit sequence is modulated into the second modulation symbol.
  • the modulating unit 144 is further configured to: perform inverse fast Fourier transform on the first modulation symbol, the second modulation symbol, the third modulation symbol, and the fourth modulation symbol, and add a cyclic prefix to obtain an orthogonal Frequency division multiplexing OFDM symbols;
  • the transmitting end further includes a sending unit 145, configured to send the OFDM symbol.
  • the present invention provides a receiving end 15 for implementing the demodulation method provided in Embodiment 6 of the present invention. As shown in FIG. 15, the receiving end 15 includes:
  • the obtaining unit 151 is configured to acquire an OFDM symbol within a transmission bandwidth sent by the transmitting end.
  • the parsing unit 152 is configured to parse the OFDM symbol to obtain a first interleaved encoded bit sequence and a second interleaved encoded bit sequence;
  • a first deinterleaver 153 configured to perform deinterleave processing on the first interleaved coded bit sequence to obtain an odd bit sequence
  • a second deinterleaver 154 configured to perform deinterleave processing on the second interleaved coded bit sequence to obtain an even bit sequence
  • the decoding unit 155 is configured to recombine the odd bit sequence and the even bit sequence, and obtain valid information bits by channel decoding.
  • the parsing unit 155 is specifically configured to:
  • the first group of subcarriers is the first half of the subcarriers of the odd subcarriers in the transmission bandwidth
  • the second group of subcarriers is the second half of the subcarriers of the odd subcarriers, where the third group of subcarriers is in the transmission bandwidth.
  • the first half of the subcarriers of the even subcarriers, the fourth group of subcarriers being the second half of the even subcarriers
  • the disclosed system, apparatus, and method may be implemented in other manners.
  • the device embodiments described above are merely illustrative.
  • the division of the unit is only a logical function division.
  • there may be another division manner for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored or not executed.
  • the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.
  • the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.
  • each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.
  • the above integrated unit can be implemented in the form of hardware or in the form of hardware plus software functional units.
  • the above-described integrated unit implemented in the form of a software functional unit can be stored in a computer readable storage medium.
  • the software functional units described above are stored in a storage medium and include instructions for causing a computer device (which may be a personal computer, server, or network device, etc.) to perform portions of the steps of the methods described in various embodiments of the present invention.
  • the foregoing storage medium includes: a USB flash drive, Mobile hard disk, read-only memory (English full name: Read-Only Memory, referred to as: ROM), random access memory (English full name: Random Access Memory, referred to as: RAM), disk or optical disk, and other media that can store program code .

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Error Detection And Correction (AREA)
  • Detection And Prevention Of Errors In Transmission (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

La présente invention se rapporte au domaine des communications. L'invention concerne un procédé et un appareil de modulation et de démodulation de code, qui peut améliorer le gain de codage d'une séquence de bits envoyée par une extrémité d'émission lors de l'obtention du gain de combinaison de diversité. Le procédé consiste à : mettre en œuvre un codage de canal sur N bits d'information, de sorte à obtenir une séquence de bits codée; déterminer M1 bits utilisés pour la retransmission et M2 bits non utilisés pour la retransmission dans la séquence de bits codée; mettre en correspondance une première séquence de bits codée de manière entrelacée qui est obtenue par entrelacement des M1 bits, avec un premier ensemble de sous-porteuses dans une largeur de bande de transmission au moyen d'un premier diagramme de constellation; répéter la première séquence de bits codée de manière entrelacée, et mettre en correspondance la première séquence de bits codée de manière entrelacée répétée avec un deuxième ensemble de sous-porteuses dans la largeur de bande de transmission à l'aide d'un deuxième diagramme de constellation; et mettre en correspondance une seconde séquence de bits codée de manière entrelacée qui est obtenue par entrelacement des M2 bits, avec un troisième ensemble de sous-porteuses dans la largeur de bande de transmission à l'aide d'un troisième diagramme de constellation.
PCT/CN2015/086424 2015-08-07 2015-08-07 Procédé et appareil de modulation et de démodulation de code WO2017024456A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1836391A (zh) * 2003-07-14 2006-09-20 松下电器产业株式会社 多载波发送设备、多载波接收设备和多载波通讯方法
CN101278487A (zh) * 2005-07-27 2008-10-01 伟俄内克斯研究公司 跳频多载波***中音调感测和零化
CN102007747A (zh) * 2008-04-18 2011-04-06 皇家飞利浦电子股份有限公司 改进的双载波调制预编码

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1836391A (zh) * 2003-07-14 2006-09-20 松下电器产业株式会社 多载波发送设备、多载波接收设备和多载波通讯方法
CN101278487A (zh) * 2005-07-27 2008-10-01 伟俄内克斯研究公司 跳频多载波***中音调感测和零化
CN102007747A (zh) * 2008-04-18 2011-04-06 皇家飞利浦电子股份有限公司 改进的双载波调制预编码

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