[go: up one dir, main page]

CN108832974B - Low-complexity demodulation method for multi-input multi-output carrier serial number modulation system - Google Patents

Low-complexity demodulation method for multi-input multi-output carrier serial number modulation system Download PDF

Info

Publication number
CN108832974B
CN108832974B CN201810411788.3A CN201810411788A CN108832974B CN 108832974 B CN108832974 B CN 108832974B CN 201810411788 A CN201810411788 A CN 201810411788A CN 108832974 B CN108832974 B CN 108832974B
Authority
CN
China
Prior art keywords
activation mode
estimation
signal
subframe
subcarrier
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201810411788.3A
Other languages
Chinese (zh)
Other versions
CN108832974A (en
Inventor
陈芳炯
呼增
温淼文
余华
季飞
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
South China University of Technology SCUT
Original Assignee
South China University of Technology SCUT
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by South China University of Technology SCUT filed Critical South China University of Technology SCUT
Priority to CN201810411788.3A priority Critical patent/CN108832974B/en
Publication of CN108832974A publication Critical patent/CN108832974A/en
Application granted granted Critical
Publication of CN108832974B publication Critical patent/CN108832974B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • 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
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • 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
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
    • H04B7/0837—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using pre-detection combining
    • H04B7/0842—Weighted combining
    • H04B7/0848—Joint weighting
    • H04B7/0854—Joint weighting using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion
    • 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
    • H04L27/2626—Arrangements specific to the transmitter only
    • H04L27/2627—Modulators

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Radio Transmission System (AREA)

Abstract

本发明提供用于多输入多输出载波序号调制系统的低复杂度解调方法。本发明通过对信号子帧中每个子载波的每种激活模式使用降维的MMSE估计，得到每种激活模式下的调制符号估计，并根据激活模式组成对应的完整估计矢量。通过使用MAP准则得到出每个子载波的激活模式和调制符号，并按顺序将子载波的估计结果组成完整的信号子帧，经过对信号子帧激活模式检测和错误激活模式的纠正后，对激活模式合法的信号子帧进行解调得到信息比特。本发明机首先使用MMSE准则估计每种激活模式下的调制符号，然后使用MAP准则计算每种激活模式下不同发送矢量的最大后验概率，通过考虑不同发送矢量的先验概率，提升每个子载的估计准确度，改善系统的误比特性能。

Figure 201810411788

The present invention provides a low-complexity demodulation method for a multiple-input multiple-output carrier sequence number modulation system. The present invention obtains the modulation symbol estimation under each activation mode by using dimension-reduced MMSE estimation for each activation mode of each subcarrier in the signal subframe, and forms a corresponding complete estimation vector according to the activation mode. The activation mode and modulation symbol of each sub-carrier are obtained by using the MAP criterion, and the estimation results of the sub-carriers are formed into a complete signal subframe in sequence. Signal subframes with valid patterns are demodulated to obtain information bits. The present invention first uses the MMSE criterion to estimate the modulation symbols in each activation mode, then uses the MAP criterion to calculate the maximum a posteriori probability of different transmission vectors in each activation mode, and improves each sub-carrier by considering the prior probability of different transmission vectors. The estimation accuracy is improved, and the bit error performance of the system is improved.

Figure 201810411788

Description

Low-complexity demodulation method for multi-input multi-output carrier serial number modulation system
Technical Field
The invention relates to a digital wireless communication technology, in particular to a low-complexity demodulation method for a multi-input multi-output carrier serial number modulation system.
Background
Multiple-input Multiple-output (MIMO) is a multi-antenna communication system, and can greatly improve system capacity and bit error performance compared with a conventional single-antenna system. Due to the high throughput of the MIMO system, the channel capacity of the system can be multiplied without increasing the spectrum resources, so that the MIMO technology becomes one of the core technologies of the next generation wireless communication.
Orthogonal frequency division multiplexing-based carrier sequence number modulation (OFDM-IM) is a novel multi-carrier transmission technology, and as an improved technology of the conventional OFDM, the technology conforms to a novel green communication technology. In the OFDM-IM technology, the sub-carriers are not activated to send modulation symbols any more, only part of the sub-carriers are activated to transmit modulation symbols, and meanwhile, the serial numbers of the activated sub-carriers are also used as a new information carrying mode to transmit information bits. Since part of the subcarriers are not activated, the OFDM has a lower Peak to average power ratio (PAPR) and smaller inter-carrier interference (ICI) compared to the conventional OFDM. In the aspect of system energy consumption, because only part of subcarriers are activated to transmit modulation symbols and the serial numbers of the activated subcarriers are also used for bit transmission, the method has higher energy efficiency and meets the requirement of the green and low-carbon development trend of the future communication industry.
The MIMO-OFDM-IM technology is used as the combination of the MIMO technology and the OFDM-IM technology, has the advantages of high frequency spectrum utilization rate, strong fading resistance, high data rate and the like, and is an improvement of the traditional MIMO-OFDM multi-carrier technology. In a MIMO-OFDM-IM system, a Maximum-likelihood (ML) receiver can achieve the best performance, but needs to search for all possible combinations, its computational complexity and modulation symbol constellation order M, the number of transmit antennas NtAnd the number N of subcarriers of each subframe in OFDM-IMsubIn relation to the number of activations K, the computational complexity increases exponentially with the number of modulation transmit antennas, thus severely limiting the use of ML receivers in practical applications. MMSE-LLR based on MMSE criterion, although reducing the demodulation complexity, has a larger performance loss than ML receiver, so in the application where the real-time performance is required, a receiver with lower complexity and less performance loss is required.
Disclosure of Invention
In order to solve the above problems, the present invention provides a low complexity demodulation method for mimo carrier number modulation system.
A low complexity demodulation method for a multiple-input multiple-output carrier serial number modulation system comprises the following steps:
a) implementation of the MAP estimation module based on MMSE criterion assistance: dividing a received signal frame into G signal sub-frames which are mutually independent according to a modulation scheme adopted by a multi-input multi-output carrier serial number modulation system sending end, and estimating and independently demodulating the sub-carriers in each signal sub-frame one by one to obtain a demodulation result of each sub-carrier; performing dimensionality reduction MMSE estimation on each possible activation mode of each subcarrier, obtaining complete transmission vector estimation according to the activation modes, then calculating the maximum posterior probability of the vector estimation of each activation mode by using an MAP criterion, and finally obtaining the estimation of the subcarrier; when the estimation of all subcarriers in the signal subframe is finished, the estimation of each subcarrier is sequentially formed into the estimation of the signal subframe;
b) implementation of the activation mode detection module: detecting the activation mode of the OFDM-IM sub-frame sent by each antenna in the signal sub-frame, and inputting all the legal sub-frames into a next-stage signal sub-frame demodulation module; if an illegal activation mode is detected, recording a corresponding transmitting antenna index, and inputting the transmitting antenna index into an error activation mode correction and error subcarrier estimation module;
c) implementation of the error activated mode correction and error subcarrier estimation module: according to the information input by the activation mode detection module, calculating LLR values of subcarriers of the OFDM-IM sub-frame with errors in the activation mode, calculating the sum of LLR values of all the activation modes, namely the sum of LLR values, and estimating the legal activation mode; estimating all OFDM-IM subframes with errors in the activation modes, using MMSE estimation on subcarriers with errors in the estimated activation modes according to the legal activation modes after re-estimation, and finally forming new signal subframe estimation by using the re-estimated vectors and subcarrier estimation vectors without errors and inputting the new signal subframe estimation to a signal subframe demodulation module;
d) the signal subframe demodulation module is realized as follows: demodulating OFDM-IM subframes corresponding to each transmitting antenna in signal subframes with legal activation modes one by one to obtain mutually independent information bits transmitted by each transmitting antenna, wherein the mutually independent information bits comprise a serial number modulation bit and a modulation symbol bit; and when the demodulation of all the G signal subframes is finished, forming the information bit sequence of the signal frame by the information bit sent by each corresponding sending antenna.
Further, the implementation of the MAP estimation module based on MMSE criterion assistance specifically includes:
s1: the received signal is processed by block de-interleaving to obtain the g-th signal subframe with a signal model of
Figure BDA0001648278710000031
For the index of the sub-frame of the signal,
Figure BDA0001648278710000032
channel matrix for the tth transmit antenna to all receive antennas, NtIn order to determine the number of transmit antennas,
Figure BDA0001648278710000033
is the OFDM-IM subframe transmitted by the t-th transmitting antenna, ugIs a frequency domain additive white noise matrix; independently demodulating the subcarriers in each signal subframe one by one, wherein the signal model of the nth subcarrier is
Figure BDA0001648278710000034
Figure BDA0001648278710000035
For subcarrier number, N, in signal subframessubIs the number of sub-carriers in a signal sub-frame, xg(N) is the nth subcarrier NtA transmitted signal vector composed of symbols transmitted by the antennas,
Figure BDA0001648278710000036
is a channel matrix corresponding to the nth sub-carrier, ug(n) is a noise vector on the nth subcarrier;
s2: the signal vector xg(n) includes mapping to M-order modulationThe activated subcarriers of the symbol set χ and the inactivated subcarriers mapped to the value of 0 are independent from each other and have the same activation probability; obtaining x according to OFDM-IM activation mode scheme selected by the transmitting endg(n) the prior probability of the subcarrier corresponding to the t-th transmitting antenna is
Figure BDA0001648278710000041
Wherein N issubThe number of subcarriers in each subframe, K is the number of active subcarriers in each OFDM-IM subframe, then the signal vector xg(n) a priori probability of
Figure BDA0001648278710000042
By taking into account the transmitted vector x per subcarrier during demodulationg(n) the prior probability improves the estimation precision of each subcarrier by the receiving end;
s3: the MMSE dimension reduction activation mode modulation symbol estimation is carried out on xg(n) deleting the channel matrix for each possible activation mode
Figure BDA0001648278710000043
Middle corresponds to xg(n) obtaining a dimension reduction channel matrix in the activation mode according to the columns corresponding to the inactivated subcarriers; calculating to obtain a dimension-reduced channel matrix corresponding to the e-th activation mode
Figure BDA0001648278710000044
MMSE equalization matrix in this mode
Figure BDA0001648278710000045
Wherein
Figure BDA0001648278710000046
Is an identity matrix, a is x in the active modeg(n) the number of inactive subcarriers, e ═ 1,2eFor active mode cableLeading; calculating to obtain MMSE equalization vector of activated subcarriers in the e-th activation mode
Figure BDA0001648278710000047
The result of MMSE modulation symbol estimation of the active subcarriers is
Figure BDA0001648278710000048
The modulation symbol vector is then in this active mode as
Figure BDA0001648278710000049
S4: estimating the symbol of MMSE
Figure BDA00016482787100000410
Forming a complete transmit vector estimate in the e-th active mode
Figure BDA00016482787100000411
Calculating the maximum posterior probability of the transmission vector estimation under all the activation modes, wherein the transmission vector estimation of the nth subcarrier is
Figure BDA0001648278710000051
And calculating to obtain the estimation of all subcarriers in the signal subframe, combining the estimation results into a complete subframe according to the sequence of the subcarriers, and inputting the complete subframe into a next-stage activation mode detection module.
Further, the specific implementation of the activation mode detection module includes:
detecting the activation mode of the OFDM-IM sub-frame correspondingly transmitted by each transmitting antenna in the signal sub-frame, and inputting the activation mode into a signal sub-frame demodulation module if all the activation modes are legal; if the activation mode is illegal, recording the transmitting antenna indexes corresponding to all error OFDM-IM sub-frames, and inputting the transmitting antenna indexes into an error activation mode correction and error sub-carrier estimation module.
Further, the implementation of the module for correcting the active error pattern and estimating the erroneous subcarriers specifically includes: calculating LLR value of subcarrier of OFDM-IM subframe with error in active mode, and according to legal active mode set C ═ C1,c2,...,cMCalculating the LLR value sum of each active mode, and selecting the active mode corresponding to the LLR value sum maximum value as the active mode estimation of the OFDM-IM subframe, namely
Figure BDA0001648278710000052
Wherein
Figure BDA0001648278710000053
For an LLR value for an OFDM-IM subframe in which the active mode is in error and corresponding to a transmit antenna index of t,
Figure BDA0001648278710000054
and is
Figure BDA0001648278710000055
When k isi≠kjWhen the temperature of the water is higher than the set temperature,
Figure BDA0001648278710000056
a subcarrier index for each active mode; after finishing the estimation of all the OFDM-IM subframes with errors in the activation mode, executing dimension-reduced MMSE symbol estimation on subcarriers with errors in the estimation in the signal subframes according to the legal activation mode, and finally forming new signal subframes by the newly obtained estimation and the subcarrier estimation without errors and inputting the new signal subframes into a signal subframe demodulation module.
Further, the implementation of the signal subframe demodulation module specifically includes: demodulating OFDM-IM subframes corresponding to each transmitting antenna of an input signal subframe one by one to obtain a serial number modulation bit and a modulation symbol bit corresponding to each OFDM-IM subframe; and when the demodulation of all the G signal subframes is finished, the information bits corresponding to each transmitting antenna obtained by demodulation form a complete information bit sequence of the MIMO-ODFM-IM signal frame.
Hair brushAnd calculating to obtain the prior probability of each constellation point mapped after the activation of the subcarrier on each antenna and the prior probability of taking a 0 value without activation by combining the mutually independent carrier serial number modulation scheme of each transmitting antenna at the transmitting end, and considering the prior probability of each subcarrier transmitting vector during demodulation to improve the estimation precision of each subcarrier at the receiving end. In each subcarrier estimation, only the channel matrix H is reserved for each active modenActivating the corresponding column of the sub-carrier to obtain a reduced-dimension channel matrix Hn,eCalculating an MMSE equalization matrix in the activation mode, estimating a modulation symbol on an activated subcarrier, putting the estimated modulation symbol at the position of the activated subcarrier according to the activation mode to obtain a transmission vector estimation in the activation mode, and calculating the prior probability of the estimation vector by using the prior probability information of each subcarrier. And calculating the maximum posterior probability value of the estimation result of each activation mode of each subcarrier to obtain the activation mode of the subcarrier and the estimation of the corresponding modulation symbol. And after calculating to obtain the estimation of all subcarriers of the signal subframe, forming complete signal subframe estimation according to the subcarrier sequence numbers. And detecting the validity of the activation mode of each OFDM-IM subframe in the signal subframe, re-estimating the activation mode of the erroneous OFDM-IM subframe, and finally performing dimension reduction MMSE estimation on the subcarrier with the error estimation according to the valid activation mode to obtain the valid signal subframe estimation of the activation mode.
The invention can be used in MIMO-OFDM-IM communication system using MQAM and MPSK modulation mode.
Compared with the prior art, the invention has the following advantages and technical effects: the invention can be used as a low-complexity maximum a posteriori probability (MMSE-MAP) receiver assisted by MMSE (minimum mean Square error) criterion. Compared with the MIMO-OFDM-IM technology, the MMSE-LLR based on the MMSE criterion has the advantage of low computational complexity, but has larger performance loss compared with an ML receiver although the demodulation complexity is reduced, so that the MMSE-LLR based on the MMSE criterion is limited in application occasions with requirements on real-time performance, and the MMSE criterion-assisted low-complexity maximum a posteriori probability (MMSE-MAP) receiver provided by the invention has the advantages of lower complexity and smaller performance loss. The receiver firstly estimates the modulation symbol in each activation mode by using MMSE (minimum mean square error) criterion, then calculates the maximum posterior probability of different transmission vectors in each activation mode by using MAP (maximum MAP) criterion, improves the estimation accuracy of each subcarrier by considering the prior probability of different transmission vectors, and improves the bit error performance of the system.
Drawings
Fig. 1 is a flow chart of a low complexity demodulation method for mimo carrier number modulation system according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a signal frame structure of a MIMO-OFDM-IM system in an example of the present invention.
Figure 3 is a graph comparing the performance of an MMSE-MAP receiver and an MMSE-LLR receiver in different MIMO configurations in an embodiment of the present invention.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, but the invention is not limited thereto, and it should be noted that those skilled in the art can implement the embodiments without specific details below.
The flow and implementation modules of the low-complexity demodulation method for the mimo carrier serial number modulation system in this example are shown in fig. 1, and the specific implementation steps are as follows.
According to the modulation mode of the carrier sequence number of each transmitting antenna at the transmitting end, a received signal frame can be divided into G signal subframes which are independent from each other, and a frame structure diagram of the received signal frame is shown in fig. 2. Taking out the g sub-frame receiving matrix of the currently demodulated signal, the signal model of the n sub-carrier is
Figure BDA0001648278710000071
Wherein G1, 2, the index of the sub-frame number of the G signal, N1, 2, NsubFor subcarrier number, y, in signal sub-framesg(n) is a received signal vector, xg(N) is represented by NtA signal vector consisting of modulation symbols of the nth subcarrier of each antenna,
Figure BDA0001648278710000072
channel matrix u corresponding to the nth sub-carrierg(n) is a noise vector on the nth subcarrier.
And independently demodulating each subcarrier in the g-th signal subframe one by one, and combining estimation results of all subcarriers into a complete signal subframe estimation after obtaining the estimation of all subcarriers in the signal subframe through demodulation.
For the nth subcarrier estimation, search calculation xg(n) all possible activation modes. For the e-th activation mode, the channel matrix is deleted
Figure BDA0001648278710000081
Middle corresponds to xgThe columns of the inactivated subcarriers in (n) are obtained to obtain the corresponding dimension-reduced channel matrix
Figure BDA0001648278710000082
Index the active mode. Computing MMSE equalization matrix in current active mode
Figure BDA0001648278710000083
Wherein
Figure BDA0001648278710000084
Is an identity matrix, a is x in the active modeg(n) number of inactive subcarriers. Calculating MMSE equalization receiving vector of active subcarrier in the active mode
Figure BDA0001648278710000085
The result of MMSE estimation of the active subcarriers is
Figure BDA0001648278710000086
In this active mode the active symbol vector is
Figure BDA0001648278710000087
According to the e-th activation mode, using
Figure BDA0001648278710000088
The middle symbol estimation result obtains the complete transmission vector estimation
Figure BDA0001648278710000089
Calculating xe(n) prior probability
Figure BDA00016482787100000810
Wherein
Figure BDA00016482787100000811
Prior probability of nth sub-carrier corresponding to t antenna
Figure BDA00016482787100000812
Calculating the maximum posterior probability of the transmission vector estimation under all the active modes according to the MAP criterion, and then estimating the nth subcarrier as
Figure BDA0001648278710000091
And after the estimation of all the subcarriers is obtained through calculation, the estimation of all the subcarriers in the signal subframe is combined together to obtain the estimation of the signal subframe.
Performing active mode detection on each estimated signal subframe, wherein the signal subframe comprises NtAnd the OFDM-IM subframes which are independent from each other sequentially check whether the activation mode of the OFDM-IM subframe transmitted by each transmitting antenna is legal or not, and record the transmitting antenna index corresponding to the error of the activation mode. If no error exists, the data is directly input into the signal subframe demodulation module to obtain the information bit sequence of each signal subframe.
When an erroneous active mode is found, calculating LLR values of subcarriers of an OFDM-IM subframe of an antenna index of which the active mode is erroneous
Figure BDA0001648278710000092
Where t is the transmit antenna index corresponding to the OFDM-IM subframe in which the active mode is in error,
Figure BDA0001648278710000093
cg(n)t,tfor MMSE equalization vector zg(n) covariance matrix
Figure BDA0001648278710000094
Diagonal element of
Figure BDA0001648278710000095
cov(xg(n)) is a covariance matrix of the transmit vector with diagonal elements divided by the t-th element of 0 and signal variance as the remainder
Figure BDA0001648278710000096
According to legal activation mode set C ═ { C ═ C1,c2,...,cMCalculating the LLR value sum of each mode, wherein
Figure BDA0001648278710000097
For each sub-carrier index of the active mode,
Figure BDA0001648278710000098
and is
Figure BDA0001648278710000099
When k isi≠kjThen (c) is performed. Selecting the activation mode corresponding to the LLR value and the median maximum value in the calculation result as the activation mode estimation of the OFDM-IM subframe, namely
Figure BDA00016482787100000910
After finishing the estimation of all the OFDM-IM subframes with errors in the active modeAnd carrying out dimension-reduced MMSE estimation on the subcarriers with errors estimated in the signal subframes according to a legal activation mode after new estimation, taking the MMSE estimation as the estimation of the subcarriers, and finally forming new signal subframes by the result of the new estimation and the estimation result of the subcarriers without errors and inputting the new signal subframes into a signal subframe demodulation module.
And each OFDM-IM subframe of the demodulated signal subframe is independently demodulated to obtain the serial number modulation bit and the modulation symbol bit of the OFDM-IM subframe corresponding to each transmitting antenna.
And after the demodulation of the G signal subframes is finished, recombining the demodulated bit sequences to obtain the complete information bit sequence of the MIMO-ODFM-IM signal frame.
Figure 3 is a graph comparing the performance of an MMSE-MAP receiver and an MMSE-LLR receiver in different MIMO configurations in an embodiment of the present invention. The MMSE-based MMSE-LLR reduces the demodulation complexity, but has larger performance loss compared with an ML receiver, so the MMSE-based MMSE-LLR is limited in application occasions with requirements on real-time performance, and the MMSE-based aided low-complexity maximum a posteriori probability (MMSE-MAP) receiver provided by the invention not only has lower complexity, but also has smaller performance loss.
The above description is an embodiment of the present invention, and is only used to help understand the method and its core idea of the present invention; the embodiments of the present invention are not limited to the above-described embodiments, and all changes, modifications, substitutions, combinations, and simplifications made in the detailed description and the application range are equivalent substitutions and are included in the protection scope of the present invention.

Claims (5)

1.用于多输入多输出载波序号调制系统的低复杂度解调方法，其特征在于，包括如下步骤：1. the low-complexity demodulation method that is used for the multiple-input multiple-output carrier sequence number modulation system, is characterized in that, comprises the steps: a)基于MMSE准则辅助的MAP估计模块的实现：根据多输入多输出载波序号调制系统发送端采用的调制方案，将接收到的信号帧分为G个相互独立的信号子帧，对每个信号子帧中子载波逐个估计独立解调得到每个子载波的解调结果；对每个子载波的每种可能的激活模式进行降维MMSE估计，按照激活模式得到完整的发送矢量估计，然后使用MAP准则计算每个激活模式的矢量估计的最大后验概率，最终得到此子载波的估计；当信号子帧中的所有子载波估计结束，将各个子载波的估计按顺序组成信号子帧的估计；a) Implementation of the MAP estimation module assisted by the MMSE criterion: According to the modulation scheme adopted by the transmitter of the MIMO carrier sequence number modulation system, the received signal frame is divided into G independent signal subframes. The subcarriers in the subframe are estimated and demodulated independently to obtain the demodulation result of each subcarrier; the dimensionality reduction MMSE estimation is performed for each possible activation mode of each subcarrier, and the complete transmission vector estimate is obtained according to the activation mode, and then the MAP criterion is used. Calculate the maximum a posteriori probability of the vector estimation of each activation mode, and finally obtain the estimation of this subcarrier; when the estimation of all subcarriers in the signal subframe ends, the estimation of each subcarrier is composed of the estimation of the signal subframe in order; b)激活模式检测模块的实现：检测信号子帧中对应每个天线发送的OFDM-IM子帧的激活模式，全部合法则输入到下一级信号子帧解调模块；如果检测到有不合法的激活模式，记录对应的发送天线索引，输入到错误激活模式纠正和出错子载波估计模块；b) Implementation of the active mode detection module: detect the active mode of the OFDM-IM subframe sent by each antenna in the signal subframe, and input all legal subframes to the next-level signal subframe demodulation module; if any illegal subframes are detected The activation mode of , record the corresponding transmit antenna index, input to the error activation mode correction and error subcarrier estimation module; c)错误激活模式纠正和出错子载波估计模块的实现：根据激活模式检测模块输入的信息，计算激活模式出错的OFDM-IM子帧子载波的LLR值，计算所有激活模式的LLR值的和即LLR值和，估计出合法的激活模式；估计所有激活模式出错的OFDM-IM子帧，对估计激活模式出错的子载波按照重新估计后合法的激活模式使用MMSE估计，最后将重新估计的矢量和没有出错的子载波估计矢量组成新的信号子帧估计，输入到信号子帧解调模块；c) Implementation of error activation mode correction and erroneous subcarrier estimation module: According to the information input by the activation mode detection module, calculate the LLR value of the OFDM-IM subframe subcarrier in the activation mode error, and calculate the sum of the LLR values of all activated modes. Sum the LLR values to estimate the legal activation mode; estimate all OFDM-IM subframes with errors in the activation mode, use MMSE estimation for the subcarriers whose activation mode is wrong according to the re-estimated legal activation mode, and finally sum the re-estimated vectors The error-free subcarrier estimation vector forms a new signal subframe estimation, which is input to the signal subframe demodulation module; d)信号子帧解调模块的实现：逐个解调激活模式合法的信号子帧中每个发送天线对应的OFDM-IM子帧，得到每个发送天线发送的相互独立的信息比特，包括序号调制比特和调制符号比特；当G个信号子帧全部解调结束后，将对应每个发送天线发送的信息比特组成信号帧的信息比特序列。d) Implementation of the signal subframe demodulation module: demodulate the OFDM-IM subframes corresponding to each transmitting antenna in the valid signal subframes in the active mode one by one, and obtain mutually independent information bits sent by each transmitting antenna, including serial number modulation Bits and modulation symbol bits; when all the G signal subframes are demodulated, the information bits corresponding to each transmitting antenna are formed into the information bit sequence of the signal frame. 2.根据权利要求1所述的用于多输入多输出载波序号调制系统的低复杂度解调方法，其特征在于所述基于MMSE准则辅助的MAP估计模块的实现具体包括：2. The low-complexity demodulation method for a MIMO carrier sequence number modulation system according to claim 1, wherein the implementation of the MAP estimation module assisted by the MMSE criterion specifically includes: S1：接收到的信号经过块解交织处理后，得到第g个信号子帧，其信号模型为
Figure FDA0003192428460000021
G为信号子帧索引，
Figure FDA0003192428460000022
为第t个发送天线到所有接收天线的信道矩阵，Nt为发送天线的个数，
Figure FDA0003192428460000023
是第t个发送天线发送的OFDM-IM子帧，ug是频域加性白噪声矩阵；对每个信号子帧中的子载波逐个独立解调处理，第n个子载波的信号模型为
Figure FDA0003192428460000024
Nsub为信号子帧中的子载波序号，Nsub为信号子帧中的子载波个数，xg(n)为第n个子载波Nt个天线发送的符号组成的发送信号矢量，
Figure FDA0003192428460000025
为第n个子载波对应的信道矩阵，ug(n)为第n个子载波上的噪声矢量；S1: After the received signal is processed by block deinterleaving, the g-th signal subframe is obtained, and its signal model is
Figure FDA0003192428460000021
G is the signal subframe index,
Figure FDA0003192428460000022
is the channel matrix from the t-th transmit antenna to all receive antennas, N t is the number of transmit antennas,
Figure FDA0003192428460000023
is the OFDM-IM subframe sent by the t-th transmitting antenna, and ug is the frequency-domain additive white noise matrix; the sub-carriers in each signal sub-frame are independently demodulated one by one, and the signal model of the n-th sub-carrier is
Figure FDA0003192428460000024
N sub is the subcarrier sequence number in the signal subframe, N sub is the number of subcarriers in the signal subframe, x g (n) is the transmitted signal vector composed of symbols sent by the nth subcarrier N t antennas,
Figure FDA0003192428460000025
is the channel matrix corresponding to the nth subcarrier, and ug (n) is the noise vector on the nth subcarrier; S2：所述信号矢量xg(n)中包括映射到M阶调制符号集合χ的激活子载波和映射为0值的未激活子载波，每个发送天线的子载波之间相互独立且具有相同的激活概率；根据发送端选取的OFDM-IM激活模式方案，得到xg(n)中第t个发送天线对应的子载波的先验概率为S2: The signal vector x g (n) includes the activated sub-carriers mapped to the M-order modulation symbol set x and the inactivated sub-carriers mapped to a value of 0, and the sub-carriers of each transmit antenna are independent of each other and have the same According to the OFDM-IM activation mode scheme selected by the transmitting end, the prior probability of the subcarrier corresponding to the t-th transmitting antenna in x g (n) is obtained as
Figure FDA0003192428460000031
Figure FDA0003192428460000031
 其中Nsub为每个子帧中子载波的个数，K为每个OFDM-IM子帧中激活子载波个数，则信号矢量xg(n)的先验概率为where N sub is the number of subcarriers in each subframe, and K is the number of activated subcarriers in each OFDM-IM subframe, then the prior probability of the signal vector x g (n) is
Figure FDA0003192428460000032
Figure FDA0003192428460000032
 通过在解调时考虑每个子载波的发送矢量xg(n)的先验概率，提高接收端对每个子载波的估计精度；By considering the prior probability of the transmission vector x g (n) of each sub-carrier during demodulation, the estimation accuracy of each sub-carrier at the receiving end is improved; S3：所述MMSE降维激活模式调制符号估计，对xg(n)中每一种可能的激活模式，删除信道矩阵
Figure FDA0003192428460000033
中对应xg(n)中未激活子载波对应的列，得到此激活模式下的降维信道矩阵；计算得到第e种激活模式对应的降维的信道矩阵
Figure FDA0003192428460000034
此模式下的MMSE均衡矩阵
Figure FDA0003192428460000035
其中INt-a为单位矩阵，a为此激活模式下xg(n)中未激活子载波的个数，e＝1,2,K,Ce为激活模式索引；计算得到第e种激活模式下激活子载波的MMSE均衡矢量S3: The MMSE dimension reduction activation mode modulation symbol estimation, for each possible activation mode in x g (n), delete the channel matrix
Figure FDA0003192428460000033
Corresponding to the column corresponding to the unactivated subcarriers in x g (n), the dimension-reduced channel matrix under this activation mode is obtained; the dimension-reduced channel matrix corresponding to the e-th activation mode is obtained by calculation
Figure FDA0003192428460000034
MMSE equalization matrix in this mode
Figure FDA0003192428460000035
where I Nt-a is the identity matrix, a is the number of unactivated subcarriers in x g (n) in the activation mode, e=1, 2, K, C e are the activation mode indices; the e-th activation is obtained by calculation MMSE equalization vector for active subcarriers in mode
Figure FDA0003192428460000036
Figure FDA0003192428460000036
 激活子载波的MMSE调制符号估计结果为The estimated result of the MMSE modulation symbol of the activated subcarrier is
Figure FDA0003192428460000037
Figure FDA0003192428460000037
 则此激活模式下调制符号矢量为
Figure FDA0003192428460000041
Then the modulation symbol vector in this active mode is
Figure FDA0003192428460000041
 S4：将MMSE的符号估计结果
Figure FDA0003192428460000042
按照第e种激活模式组成此种激活模式下完整的发送矢量估计
Figure FDA0003192428460000043
计算所有激活模式下发送矢量估计的最大后验概率，第n个子载波的发送矢量估计为S4: The symbol estimation result of MMSE
Figure FDA0003192428460000042
According to the e-th activation mode, the complete transmission vector estimate in this activation mode is composed
Figure FDA0003192428460000043
Calculate the maximum a posteriori probability of the transmit vector estimate in all active modes, and the transmit vector estimate for the nth subcarrier is
Figure FDA0003192428460000044
Figure FDA0003192428460000044
 计算得到信号子帧中所有子载波的估计，将估计结果按子载波顺序组合成完整的子帧，输入下一级激活模式检测模块。The estimation of all sub-carriers in the signal sub-frame is obtained by calculation, the estimation results are combined into a complete sub-frame according to the sub-carrier order, and input to the next-level activation mode detection module. 3.根据权利要求1所述的用于多输入多输出载波序号调制系统的低复杂度解调方法，其特征在于所述的激活模式检测模块的具体实现包括：3. The low-complexity demodulation method for a MIMO carrier sequence number modulation system according to claim 1, wherein the specific implementation of the activation mode detection module comprises: 检测信号子帧中每个发送天线对应发送的OFDM-IM子帧的激活模式，如果全部合法，则输入到信号子帧解调模块；如果出现激活模式不合法情况，记录所有出错OFDM-IM子帧对应的发送天线索引，输入到错误激活模式纠正和出错子载波估计模块。Detect the activation mode of the OFDM-IM subframe sent by each transmitting antenna in the signal subframe. If all of them are legal, they are input to the signal subframe demodulation module; if the activation mode is illegal, record all error OFDM-IM subframes. The transmit antenna index corresponding to the frame is input to the error activation mode correction and error subcarrier estimation module. 4.根据权利要求1所述的用于多输入多输出载波序号调制系统的低复杂度解调方法，其特征在于所述的错误激活模式纠正和出错子载波估计模块的实现具体包括：计算激活模式出错的OFDM-IM子帧的子载波的LLR值，按照合法激活模式集合C＝{c1,c2,K,cM}计算每一种激活模式的LLR值和，选择LLR值和中最大值对应的激活模式为此OFDM-IM子帧的激活模式估计，即
Figure FDA0003192428460000045
其中
Figure FDA0003192428460000051
为激活模式出错且对应发送天线索引为t的OFDM-IM子帧的LLR值，
Figure FDA0003192428460000052
且
Figure FDA0003192428460000053
当ki≠kj时，
Figure FDA0003192428460000054
为每个激活模式的子载波索引；完成所有激活模式出错的OFDM-IM子帧的估计后，对信号子帧中估计出错的子载波按照合法的激活模式执行降维的MMSE符号估计，最后将重新得到的估计和没有出错的子载波估计组成新的信号子帧，输入到信号子帧解调模块。4. the low-complexity demodulation method that is used for MIMO carrier sequence number modulation system according to claim 1, it is characterized in that the realization of described error activation mode correction and error subcarrier estimation module specifically comprises: calculating activation For the LLR value of the subcarrier of the OFDM-IM subframe with the wrong mode, calculate the LLR value sum of each activation mode according to the legal activation mode set C={c 1 , c 2 , K, c M }, and select the LLR value and the middle The activation mode corresponding to the maximum value is the activation mode estimation of this OFDM-IM subframe, that is,
Figure FDA0003192428460000045
in
Figure FDA0003192428460000051
is the LLR value of the OFDM-IM subframe with an error in the activation mode and the corresponding transmit antenna index t,
Figure FDA0003192428460000052
and
Figure FDA0003192428460000053
When k i ≠ k j ,
Figure FDA0003192428460000054
is the subcarrier index of each activation mode; after completing the estimation of all OFDM-IM subframes with errors in the activation mode, perform dimensionality reduction MMSE symbol estimation for the subcarriers with errors in the estimated subframes in the signal subframe according to the legal activation mode, and finally The re-obtained estimation and the error-free subcarrier estimation form a new signal subframe, which is input to the signal subframe demodulation module. 5.根据权利要求1所述的用于多输入多输出载波序号调制系统的低复杂度解调方法，其特征在于所述的信号子帧解调模块的实现具体包括：对输入的信号子帧的每个发送天线对应的OFDM-IM子帧逐个解调，得到每个OFDM-IM子帧对应的序号调制比特和调制符号比特；当G个信号子帧全部解调结束后，将解调得到每个发送天线对应的信息比特组成完整的MIMO-ODFM-IM信号帧的信息比特序列。5. The low-complexity demodulation method for a multiple-input multiple-output carrier sequence number modulation system according to claim 1, wherein the realization of the signal subframe demodulation module specifically comprises: to the input signal subframe The OFDM-IM subframes corresponding to each transmitting antenna are demodulated one by one, and the serial number modulation bits and modulation symbol bits corresponding to each OFDM-IM subframe are obtained; when all the G signal subframes are demodulated, the demodulation obtained The information bits corresponding to each transmit antenna form the information bit sequence of a complete MIMO-ODFM-IM signal frame.
CN201810411788.3A 2018-05-02 2018-05-02 Low-complexity demodulation method for multi-input multi-output carrier serial number modulation system Active CN108832974B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201810411788.3A CN108832974B (en) 2018-05-02 2018-05-02 Low-complexity demodulation method for multi-input multi-output carrier serial number modulation system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201810411788.3A CN108832974B (en) 2018-05-02 2018-05-02 Low-complexity demodulation method for multi-input multi-output carrier serial number modulation system

Publications (2)

Publication Number Publication Date
CN108832974A CN108832974A (en) 2018-11-16
CN108832974B true CN108832974B (en) 2021-09-21

Family

ID=64147924

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201810411788.3A Active CN108832974B (en) 2018-05-02 2018-05-02 Low-complexity demodulation method for multi-input multi-output carrier serial number modulation system

Country Status (1)

Country Link
CN (1) CN108832974B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114301545B (en) * 2021-12-03 2024-04-19 网络通信与安全紫金山实验室 Signal detection method, device, electronic device and storage medium

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101057469A (en) * 2004-09-17 2007-10-17 诺基亚公司 Iterative and Turbo-based method and apparatus for equalization of spread-spectrum downlink channels
CN105591717A (en) * 2015-12-31 2016-05-18 电子科技大学 Low-complexity detection method for MIMO-OFDM system with subcarrier index modulation
CN106453190A (en) * 2016-10-10 2017-02-22 东南大学 Multi-user sub-carrier index modulation orthogonal frequency-division multiplexing (SIM-OFDM) transmission method
CN107302419A (en) * 2017-06-16 2017-10-27 电子科技大学 A kind of low complex degree detection method for MIMO ofdm systems
EP3280164A2 (en) * 2016-07-14 2018-02-07 Icomera AB Distributed wireless communication system for moving vehicles

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104618082B (en) * 2015-01-30 2018-04-06 电子科技大学 A kind of multiple antennas SIM OFDM multi-carrier wireless transmission methods

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101057469A (en) * 2004-09-17 2007-10-17 诺基亚公司 Iterative and Turbo-based method and apparatus for equalization of spread-spectrum downlink channels
CN105591717A (en) * 2015-12-31 2016-05-18 电子科技大学 Low-complexity detection method for MIMO-OFDM system with subcarrier index modulation
EP3280164A2 (en) * 2016-07-14 2018-02-07 Icomera AB Distributed wireless communication system for moving vehicles
CN106453190A (en) * 2016-10-10 2017-02-22 东南大学 Multi-user sub-carrier index modulation orthogonal frequency-division multiplexing (SIM-OFDM) transmission method
CN107302419A (en) * 2017-06-16 2017-10-27 电子科技大学 A kind of low complex degree detection method for MIMO ofdm systems

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
Low-Complexity LLR Calculation for OFDM With Index Modulation;Zeng Hu等;《IEEE WIRELESS COMMUNICATIONS LETTERS》;20180206;全文 *
Low-Complexity Near-Optimal Detector for Multiple-Input Multiple-Output OFDM with Index Modulation;Beixiong Zheng等;《2017 IEEE International Conference on Communications (ICC)》;20170731;全文 *
Multiple-Input Multiple-Output OFDM With Index Modulation: Low-Complexity Detector Design;Beixiong Zheng等;《EEE TRANSACTIONS ON SIGNAL PROCESSING》;20170223;全文 *

Also Published As

Publication number Publication date
CN108832974A (en) 2018-11-16

Similar Documents

Publication Publication Date Title
CN106357311B (en) A detection method for MIMO-OFDM system based on carrier index modulation
CN101056302B (en) Channel and Carrier Frequency Offset Estimation Method Based on UKF in OFDM System
CN102882575B (en) For determining the method and apparatus of channel condition information
US8411802B2 (en) Iterative estimator and method of channel and noise variance for multiple input multiple output orthogonal frequency division multiplexing system
CN105591717B (en) The low complex degree detection method of MIMO-OFDM system for carrier index modulation
Tomasoni et al. Efficient OFDM channel estimation via an information criterion
CN107624235B (en) Apparatus and method for estimating downlink channel in wireless communication system
CN104320369B (en) A kind of alternative manner based on channel estimation errors and data detection error
JP2009060616A (en) Low complexity signal detection method and detection apparatus for use in MIMO system
Khan et al. Data aided channel estimation for MIMO-OFDM wireless systems using reliable carriers
CN106533590A (en) Uplink channel quality measurement method based on receiver EVM
EP2559214B1 (en) Channel estimation for equalizer using serial localization with indecision
CN114268352B (en) Detection method of NR uplink control channel format 1
Liu et al. Robust semi-blind estimation of channel and CFO for GFDM systems
CN108832974B (en) Low-complexity demodulation method for multi-input multi-output carrier serial number modulation system
CN109617851B (en) A channel estimation method and device based on DFT smoothing filtering
CN108768475B (en) Low-complexity ML receiver method for MIMO-OFDM-IM
CN109167748B (en) Partial maximum likelihood detection method based on energy sorting
CN104717045B (en) A kind of arrangement of pilot tone determines method and base station
CN106856462B (en) Detection method under spatial modulation multidiameter fading channel
CN101599928A (en) Interference Elimination Method and Related Equipment
CN104780130A (en) Improved pilot-frequency-based SIM-OFDM channel estimation method
CN105337685A (en) Turbo detection method and device
RU2405254C2 (en) Evaluation method of data transmission channel in wireless communication system (versions)
Yang et al. On the Design of Superimposed Pilots in MIMO-OFDM with Index Modulation

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant