CN114844598A - Multi-diversity OFDM-IM modulation and demodulation method thereof - Google Patents

Multi-diversity OFDM-IM modulation and demodulation method thereof Download PDF

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CN114844598A
CN114844598A CN202210371660.5A CN202210371660A CN114844598A CN 114844598 A CN114844598 A CN 114844598A CN 202210371660 A CN202210371660 A CN 202210371660A CN 114844598 A CN114844598 A CN 114844598A
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侯书丹
呼增
李涛
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Guangzhou Institute of Technology of Xidian University
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
    • H04L1/0045—Arrangements at the receiver end
    • H04L1/0054—Maximum-likelihood or sequential decoding, e.g. Viterbi, Fano, ZJ algorithms
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
    • H04L1/0056—Systems characterized by the type of code used
    • H04L1/0071—Use of interleaving
    • 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
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2649—Demodulators
    • H04L27/265—Fourier transform demodulators, e.g. fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Abstract

The invention discloses a multi-diversity transmitting method based on OFDM-IM, relating to the field of wireless communication. The technical scheme includes that the serial number pattern of OFMD-IM subblocks is designed according to system requirements by grouping subcarriers available to a system at a transmitting end, each subblock is used as a unit for modulation, the serial number pattern in each subblock and a traditional modulation symbol transmitted by an active subcarrier transmit the same information bit, and the subblocks are used as a whole to form multi-diversity transmission. A multi-step demodulation receiver based on single subcarrier calculation is designed at a receiving end, the maximum likelihood calculation of the single subcarrier is realized by utilizing the orthogonality among the subcarriers, and then the estimation of a symbol vector sent by a subblock is realized based on a sequence number modulation pattern, so that the calculation complexity of the receiving end can be further reduced. The invention can obtain better error bit performance under the same transmitting diversity and can improve the reliability of information transmission.

Description

Multi-diversity OFDM-IM modulation and demodulation method thereof
Technical Field
The invention relates to the field of wireless communication, in particular to a multi-diversity transmission method based on OFDM-IM and a demodulation method thereof.
Background
OFDM is one of the key technologies of 5G and next-generation mobile communication technologies, and frequency selective fading caused by multipath transmission can be converted into flat fading through processing of signals in the frequency domain, thereby effectively reducing the computational complexity of signal equalization processing. In 5G and the next generation Mobile Communication network 6G, 3 main application scenarios are defined for the characteristics of different services and the requirements for wireless information transmission, namely Enhanced Mobile Broadband (eMBB), large-scale Machine Type/mass internet of things Communication (mtc) and high-reliability Low-Latency Communication (urrllc). OFDM finds application in multiple wireless transmission technology protocols in the above-described wireless communication scenario.
The carrier serial number modulation OFDM-IM is an improvement of the traditional OFDM, and a mode pattern of a subcarrier serial number domain is designed by introducing a serial number modulation technology, so that the Bit Error Rate (BER) performance, the spectrum efficiency and the energy efficiency of a system are further improved. In a sequence number modulation aided system, information bits are transmitted in two ways, the first being in a sequence number pattern and the second being in a modulation symbol sent over an active subcarrier. Compared with modulation symbols, the serial number pattern of the active subcarriers has better robustness, and the BER performance of the system can be improved by introducing serial number modulation.
Therefore, researchers are dedicated to develop a multi-diversity transmission method based on a serial number modulation technology, and a multi-diversity transmission technical scheme is designed by combining a serial number modulation pattern and a traditional modulation symbol in a carrier serial number modulation OFDM-IM system.
Disclosure of Invention
The invention designs a multi-diversity transmission method and a low-complexity receiver method by taking subblocks as units in OFDM-IM, utilizes the advantage of better robustness of serial number modulation, improves the BER performance of a system, and realizes high-reliability wireless transmission of information and high-efficiency demodulation of a receiving end.
In order to achieve the above object, the present invention provides a multi-diversity transmitting method based on an OFDM-IM system, and the technical solution of the present invention includes the following steps:
Step 1, initializing an OFDM system and converting N B The available subcarriers are divided into G subblocks for transmitting information bits, where each subblock contains N-N subblocks B and/G sub-carriers, each sub-block independently modulating and demodulating and transmitting different information bits.
And 2, selecting K subcarriers from N subcarriers of each subblock for sending modulation symbols, wherein the available sequence number mode patterns have C (N, K) in total, and C (-) represents a combination number function. The input m information bits are divided into G groups, where each group p is m/G information bits. Selecting M in sequence number modulation IM ＝2 P A sequence number pattern for each sub-block, using a sequence number of M-M IM Is used for the modulation of conventional modulation symbols.
Step 3, selecting an active subcarrier sequence number mode pattern through sequence number modulation based on p information bits input by the G (G is more than or equal to 1 and less than or equal to G) th sub-block
Figure BDA0003588946480000011
And obtaining a sending modulation symbol s through modulation symbol mapping.
Step 4, mapping the modulation symbol s obtained by the g sub-block to a serial number mode pattern
Figure BDA0003588946480000021
Obtaining the sending symbol vector of the sub-block at the corresponding position of the determined activated sub-carrier
Figure BDA0003588946480000022
Wherein the symbol x n ＝s，
Figure BDA0003588946480000023
x n ＝0，
Figure BDA0003588946480000024
n＝1，2，...，N，g＝1，2，...，G。
Step 5, connecting the symbol vectors of the G sub-blocks according to the sequence to obtain a complete OFDM-IM block symbol vector, and performing block interleaving with the depth of alpha on the frequency domain symbol vector to obtain a final OFDM-IM block frequency domain symbol vector x F 。
Step 6, the frequency domain symbol vector x F Obtaining a time domain signal vector x through inverse Fourier transform T Adding the cyclic prefix CP to obtain the final transmitted signal vectorAmount of the compound (A).
Step 7, the time domain signal is sent to a receiving end through a frequency selective fading channel to obtain a time domain receiving signal vector y T . Remove y T After the cyclic prefix CP, a frequency domain received signal vector is obtained through Fourier transform, and after block de-interleaving, a frequency domain received signal vector y for restoring the original sequence is obtained F Can be expressed as
y F ＝γdiag(h)x F +w，
Wherein
Figure BDA0003588946480000025
For the power distribution factor, y, of the transmitting end at constant power F Is a frequency domain received signal vector, h is a frequency domain channel response vector, w is a mean of 0 and a variance of N 0 Gaussian white noise vector.
And 8, dividing the frequency domain received signal vector into G sub-blocks according to the grouping mode of the sub-blocks at the transmitting end, and independently demodulating and calculating each sub-block. The G (G is more than or equal to 1 and less than or equal to G) th sub-block received signal model is
Figure BDA0003588946480000026
Step 9, transmitting symbol vector set constructed by taking sub-block as unit
Figure BDA00035889464800000212
In the set, there is 2 p A vector of symbols, one for each sequence number modulation pattern. Calculating the estimation of the sub-block based on the maximum likelihood criterion calculated in the sub-block unit based on the received signal model in step 8
Figure BDA0003588946480000027
Step 10, transmitting symbol vector set based on sub-block
Figure BDA00035889464800000213
Constructing a subset of symbol sets corresponding to each subcarrier
Figure BDA00035889464800000214
Wherein N is 1, 2. Symbol subset corresponding to nth subcarrier in maximum likelihood criterion calculation based on single subcarrier
Figure BDA00035889464800000215
The metric value of each symbol in the set is
p n (s n )＝|y n -γh n s n | 2
Wherein y is n Is a frequency domain received signal of the nth subcarrier,
Figure BDA00035889464800000216
the symbols in the modulated symbol subset for the nth subcarrier.
Step 11, based on the metric value of each symbol in the modulation symbol subset corresponding to each subcarrier obtained in step 10, the estimation of the g-th sub-block is
Figure BDA0003588946480000028
Maximum likelihood receiver based on single subcarrier calculation has a computational complexity of floating point calculation
Figure BDA0003588946480000029
Wherein
Figure BDA00035889464800000210
Is the average of the number of symbols of the modulation symbol subset of the subcarriers.
By estimating sub-blocks
Figure BDA00035889464800000211
The transmitted information bits are obtained by demodulation.
Further, the system signal-to-noise ratio is defined as ρ ═ E b /N 0 In which E b ＝(N B +N CP ) Where/m is the average energy per bit,N CP is the length of the cyclic prefix.
Further, the received signal vector of the g sub-block in step 8 is
Figure BDA0003588946480000031
Further, the modulation symbol subset in step 10
Figure BDA0003588946480000035
To in a set of modulation symbols
Figure BDA0003588946480000036
The set of all transmitted modulation symbols for the sub-carrier includes non-null constellation modulation symbols and '0' symbols.
Drawings
FIG. 1 is a schematic diagram of a transmit end implementation of the present invention;
fig. 2 is a BER performance comparison simulation diagram of a multi-diversity OFDM-IM, a conventional OFDM repeated transmission scheme, an OFDM without transmission diversity gain, and an OFDM-IM scheme when a modulation symbol adopts a 4QAM constellation, based on OFDM-IM subblock parameters N being 4 and K being 2, wherein a subblock-based maximum likelihood receiver of the multi-diversity OFDM-IM is identified as a subblock receiver, and a receiver calculated based on multi-step demodulation of a maximum likelihood criterion of a single subcarrier is identified as a subcarrier receiver.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.
The invention aims to solve the requirement of high-reliability wireless transmission of information in a next generation mobile communication network, combines the advantage of high robustness of a sequence number pattern, designs a multi-diversity transmission method for realizing the information by taking each subblock as a unit, and improves the reliability of the information according to the requirement of a system.
The modulation method of the multi-diversity OFDM-IM is designed on the basis of the subcarrier of one OFDM symbol period.
As shown in fig. 1, one OFDM N of the block B The sub-carriers are divided into G sub-blocks independent of each other, each sub-block performing the same modulation and demodulation method independent of each other, wherein each sub-block includes N-N B G sub-carriers.
The m input information bits transmitted per OFDM symbol are divided into G groups, each group of p-m/G information bits being used for multi-diversity modulation of the subblocks.
Multiple diversity modulation is performed in units of each sub-block, where each sub-block has K active sub-carriers for transmitting modulation symbols. According to the sequence number modulation principle, C (N, K) sequence number mode patterns can be used for sequence number modulation, and M is selected according to system requirements IM ＝2 p C (N, K) sequence number pattern is used for sequence number modulation.
The traditional modulation symbol mapping adopts M-M IM The constellation diagram of order, through the sequence number pattern taking subblock as unit and the traditional constellation diagram, forms the multi-diversity transmission. In the multi-diversity OFDM-IM modulation, the sequence number pattern and the conventional modulation symbol transmit the same p information bits, and it can be known that the sequence number modulation pattern and the modulation symbol in the conventional constellation have a corresponding relationship at this time.
When active subcarrier transmission
Figure BDA0003588946480000032
When the constellation diagram symbol is used, the subcarrier N of each subblock is 4, the number of active subcarriers is 2, the sequence number pattern that each subblock can use for sequence number modulation has C (4, 2) 6, 4 of them are used for sequence number modulation, which can be expressed as
Figure BDA0003588946480000033
The sequence number pattern resulting from the modulation corresponds to a 4QAM modulation symbol given the input information bits.
Transmitting symbol vector set constructed by using sub-block as unit
Figure BDA0003588946480000037
Set of
Figure BDA0003588946480000038
Has a total of 2 p A vector of symbols, one for each sequence number modulation pattern.
For the sequence number modulation process of the G (G is more than or equal to 1 and less than or equal to G) sub-block, based on the input p information bits, selecting an active sub-carrier sequence number mode pattern by sequence number modulation
Figure BDA0003588946480000034
And determining the serial number of the activated sub-carrier used for sending the modulation symbol in the g sub-block, and mapping by a constellation diagram to obtain a sending modulation symbol s.
Mapping modulation symbol s obtained from g-th sub-block to sequence number pattern
Figure BDA0003588946480000041
Is obtained at the position corresponding to the activated subcarrier
Transmitted symbol vector of sub-block
Figure BDA0003588946480000042
Wherein the symbol x n ＝s，
Figure BDA0003588946480000043
x n ＝0，
Figure BDA0003588946480000044
n＝1，2，...，N，g＝1，2，...，G。
The obtained transmitting symbol vectors of the G sub-blocks are sequentially combined into a complete OFDM-IM block transmitting symbol vector, the frequency domain symbol vector is subjected to block interleaving with the depth of alpha, and a final OFDM-IM block frequency domain symbol vector x is obtained F 。
Vector of frequency domain symbols x F Obtaining a time domain signal vector x through inverse Fourier transform T And adding a Cyclic Prefix (CP) to obtain a final sending signal vector.
The time domain signal is transmitted to a receiving end through a frequency selective Rayleigh fading channel, and the obtained time domain receiving signal vector is y T . Remove y T After the cyclic prefix CP, the frequency domain receiving is obtained through Fourier transformationThe signal vector is subjected to block de-interleaving to obtain a frequency domain received signal vector y which restores the original sequence F The signal model is
y F ＝γdiag(h)x F +w，
Wherein
Figure BDA0003588946480000045
For the power distribution factor, y, of the transmitting end at constant power F Is a frequency domain received signal vector, h is a frequency domain channel response vector, w is a mean of 0 and a variance of N 0 Gaussian white noise vector. The system signal-to-noise ratio is defined as ρ ═ E b /N 0 In which E b ＝(N B +N CP ) M is the average energy in bits, N CP Is the length of the cyclic prefix.
And according to the grouping mode of the sub-blocks at the transmitting end, dividing the frequency domain received signal vector into G sub-blocks, and independently demodulating and calculating each sub-block.
The G (G is more than or equal to 1 and less than or equal to G) th sub-block received signal model is
Figure BDA0003588946480000046
Wherein
Figure BDA0003588946480000047
For the frequency domain received signal model of the first sub-block, h g ＝[h 1 ，h 2 ，...，h N ] T For frequency domain channel response information, w g ＝[w 1 ，w 2 ，...，w N ] T Is a frequency domain gaussian white noise vector.
Sub-block based transmit symbol vector set
Figure BDA00035889464800000413
And received signal model
Figure BDA0003588946480000048
The estimation calculated by the maximum likelihood criterion of the sub-block calculation is
Figure BDA0003588946480000049
The method considers the orthogonality among subcarriers and the characteristic of each subcarrier transmitting symbol after being modulated by sequence number, and is based on the transmitting symbol vector set of the subblocks
Figure BDA00035889464800000414
Constructing a subset of symbol sets corresponding to each subcarrier
Figure BDA00035889464800000415
Wherein N is 1, 2. Symbol subset corresponding to nth subcarrier in maximum likelihood calculation based on single subcarrier
Figure BDA00035889464800000416
The metric value of each symbol in the set is
p n (s n )＝|y n -γh n s n | 2 ，
Wherein y is n Is a frequency domain received signal of the nth subcarrier,
Figure BDA00035889464800000417
the symbols in the modulated symbol subset for the nth subcarrier. Modulation symbol subset
Figure BDA00035889464800000418
To in a set of modulation symbols
Figure BDA00035889464800000419
The nth subcarrier of the set of modulation symbols comprises constellation modulation symbols and '0' symbols.
Based on the calculated metric value of each symbol in the modulation symbol subset of each subcarrier, the estimation of the g-th sub-block is
Figure BDA00035889464800000410
The maximum likelihood receiver based on single subcarrier calculation calculates the floating point calculation complexity of each subblock estimation as
Figure BDA00035889464800000411
Wherein
Figure BDA00035889464800000412
Is the average of the number of symbols of the modulation symbol subset of the subcarriers.
By estimating sub-blocks
Figure BDA0003588946480000051
The transmitted information bits are obtained by demodulation.
The invention can be further illustrated by case simulation:
according to the invention, simulation result data and a simulation graph are obtained through MATLAB platform simulation.
1. Simulation conditions are as follows:
setting the number of OFDM subcarriers to be N in simulation B Each OFDM-IM sub-block has N-4 sub-carriers, where K-2 are active sub-carriers for transmitting 4QAM constellation modulation symbols. The wireless channel is a frequency selective Rayleigh fading channel, the maximum time delay of the channel is 10 sampling time slots, the length of a cyclic prefix CP is 16-over-sampling periods, a receiver algorithm adopts a maximum likelihood receiver based on subblock calculation and a multi-step calculation receiver based on single subcarrier maximum likelihood calculation, the maximum likelihood receiver based on subblock calculation in the multi-diversity OFDM-IM in the figure represents a subblock receiver, and the multi-step calculation receiver based on large likelihood calculation is represented as a subcarrier receiver.
2. Emulated content
The simulation contents are that the multi-diversity OFDM-IM method of the invention is directly compared with the traditional OFDM-based method for repeatedly transmitting modulation symbols to obtain multi-transmission diversity gain, and the comparison between the multi-diversity method and the traditional OFDM and OFDM-IM methods without transmission diversity can be obtained.
The abscissa in FIG. 2 is the signal-to-noise ratio, singlyThe bit is dB and the ordinate is the system BER performance. As can be seen from fig. 2, the 3-fold diversity schemes all obtain BER performance significantly better than the conventional non-diversity scheme, verifying that the present invention can achieve 3-fold transmit diversity gain. The receiver based on the multi-step calculation of the maximum likelihood calculation of the single subcarrier adopts the maximum likelihood criterion in the calculation of each subcarrier, and the multi-step calculation method utilizes the orthogonality among the subcarriers, so that the receiver based on the maximum likelihood calculation of the sub-blocks can effectively reduce the calculation complexity and simultaneously obtain the same system BER performance. In comparison of the conventional OFDM scheme with 3-times transmit diversity and the present invention, it can be observed that the present invention can obtain a better BER performance when the BER is 10 because the sequence number pattern has a better robustness -5 A gain of about 0.9dB can be obtained compared to the conventional OFDM multi-diversity scheme. Simulation results prove that the invention can obtain multiple transmit diversity gains and can obtain a scheme which is superior to the scheme of obtaining the transmit diversity gain by transmitting the modulation symbols for multiple times by the traditional OFMD.

Claims (8)

1. A multi-diversity gain transmission method and a low-complexity demodulation algorithm are applied to an OFDM-IM (Orthogonal frequency division multiplexing with index modulation) system, and are characterized in that:
s1, processing frequency domain signals by taking an OFDM symbol period block as a basic unit;
n for each OFMD symbol period B Dividing frequency domain subcarrier into G OFDM-IM subblocks, each subblock containing N-N B the/G sub-carriers perform modulation and demodulation signal processing by taking sub-blocks as units, and the signal processing among the sub-blocks is independent;
s2, in the signal modulation of each sub-block, the information bits are transmitted by the active sub-carrier sequence number pattern and the modulation symbol sent by the active sub-carrier, that is, the information transmission includes two modes, i.e., the sequence number pattern and the conventional modulation symbol;
in the modulation of the sending end of each sub-block, the serial number pattern and the traditional modulation symbol send the same signal bit, and the multi-diversity sending of information bits is realized by taking the sub-blocks as a whole in a plurality of information transmission modes;
s3, dividing m information bits input by each OFDM-IM block into G groups, wherein p is m/G information bits sent by each sub-block, and mapping the sequence number pattern of the active sub-carrier of the sub-block by the active sub-carrier sequence number pattern
Figure FDA0003588946470000013
Obtaining a transmitted modulation symbol s through constellation mapping;
forming the obtained sequence number pattern and modulation symbol into transmission symbol vector of sub-block
Figure FDA0003588946470000011
Wherein
Figure FDA0003588946470000014
The determined K activated subcarriers all send modulation symbols s;
s4, connecting the transmitting symbol vectors of the G sub-blocks according to the sequence to obtain the complete transmitting symbol vector of the OFDM-IM block, and interleaving the frequency domain symbol vector with the depth of alpha to obtain the final frequency domain symbol vector x of the OFDM-IM block F ；
Transmitting a frequency domain symbol vector x F Obtaining a time domain sending signal vector x after inverse Fourier transform T Adding Cyclic Prefix (CP) to obtain a final sending symbol vector;
s5, after transmission in frequency selective fading channel, obtaining time domain received signal vector y at receiving end T ；
Firstly, removing a Cyclic Prefix (CP) from a time domain received signal vector, and then obtaining a frequency domain received signal y of an OFDM-IM block through Fourier transform;
according to the sub-block division mode of signal modulation, the frequency domain received signal vector is divided into G sub-blocks, and the frequency domain received signal vector of the G (G is more than or equal to 1 and less than or equal to G) sub-block is
Figure FDA0003588946470000012
S6, carrying out demodulation calculation by taking each sub-block as a unit, calculating to obtain the estimation of the transmitted symbol vector of each sub-block by using the maximum likelihood criterion, and demodulating to obtain the transmitted information bit;
S7, decomposing the maximum likelihood criterion receiver based on sub-block calculation into two steps of receivers based on single sub-carrier calculation of maximum likelihood criterion by utilizing orthogonality among sub-carriers, obtaining estimation of each sub-block through sub-block overall judgment based on calculation results of each sub-carrier, and demodulating to obtain information bits sent by the sub-blocks.
2. The multi-diversity OFDM-IM modulation method of claim 1, wherein in step S2, the whole sub-block is used as a modulation unit, and a sequence number pattern set having the same order as the constellation is designed to implement multi-diversity transmission:
when M-order constellation is used for modulation symbols, M is used IM The M number pattern is used for number modulation, and forms multiple transmission diversity with the modulation symbols transmitted by the K number of active subcarriers.
3. The multi-diversity OFDM-IM modulation method according to claim 1, wherein the sequence number pattern obtained from the input p information bits in step S3 corresponds to the modulation symbol and has a total of 2 p Individual sub-block transmit vectors forming a set of transmit symbol vectors
Figure FDA0003588946470000024
4. The multi-diversity OFDM-IM modulation method of claim 1, wherein the frequency domain received signal vector of the g-th sub-block in step S5 is
Figure FDA0003588946470000021
Wherein G is 1, 2., G,
Figure FDA0003588946470000025
for the power distribution factor, y, of the transmitting end at constant power F Is a frequency domain received signal vector, h is a frequency domain channel response vector, w is a mean of 0 and a variance of N 0 White gaussian noise vector.
5. The multi-diversity OFDM-IM modulation method of claim 1, wherein the subblock transmission symbol vector calculated by the maximum likelihood criterion in the subblock unit in step S6 is estimated as
Figure FDA0003588946470000022
And the information bits are obtained by demodulating the transmitted symbol estimation of the sub-block.
6. The multi-diversity OFDM-IM modulation method of claim 1 wherein step S7 is performed by transmitting a set of symbol vectors based on a calculation of a single subcarrier
Figure FDA0003588946470000027
Obtaining a subset of modulation symbols for each subcarrier
Figure FDA0003588946470000026
Computing metric values for each symbol in a subset of modulated symbols based on maximum likelihood criterion
p n (s n )＝|y n -γh n s n | 2
Wherein y is n Is a frequency domain received signal of the nth subcarrier,
Figure FDA0003588946470000028
is a symbol in the nth subcarrier subset.
7. The multi-diversity OFDM-IM modulation method of claim 1, wherein the step S7 comprises calculating sub-block estimates based on the modulation symbol metric values in the modulation symbol subsets corresponding to each sub-carrier obtained in step S6
Figure FDA0003588946470000023
8. The per-subcarrier modulation symbol subset of claim 6
Figure FDA0003588946470000029
The symbols in (1) include a constellation symbol and a '0' symbol.
CN202210371660.5A 2022-04-11 2022-04-11 Multi-diversity OFDM-IM modulation and demodulation method thereof Pending CN114844598A (en)

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Application publication date: 20220802