CN113810325B - Multi-antenna OTFS (optical transmission and frequency shift keying) modulation method and system based on spatial modulation - Google Patents

Multi-antenna OTFS (optical transmission and frequency shift keying) modulation method and system based on spatial modulation Download PDF

Info

Publication number
CN113810325B
CN113810325B CN202110918843.XA CN202110918843A CN113810325B CN 113810325 B CN113810325 B CN 113810325B CN 202110918843 A CN202110918843 A CN 202110918843A CN 113810325 B CN113810325 B CN 113810325B
Authority
CN
China
Prior art keywords
antenna
sequence
otfs
symbol
domain signal
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
CN202110918843.XA
Other languages
Chinese (zh)
Other versions
CN113810325A (en
Inventor
张春琼
冯丹
刘孟孟
白宝明
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.)
Xidian University
Original Assignee
Xidian University
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 Xidian University filed Critical Xidian University
Priority to CN202110918843.XA priority Critical patent/CN113810325B/en
Publication of CN113810325A publication Critical patent/CN113810325A/en
Application granted granted Critical
Publication of CN113810325B publication Critical patent/CN113810325B/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
    • H04L27/2626—Arrangements specific to the transmitter only
    • H04L27/2627—Modulators
    • 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
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/068—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission using space frequency diversity
    • 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
    • H04L27/2655—Synchronisation arrangements
    • 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
    • H04L27/2655—Synchronisation arrangements
    • H04L27/2689—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation
    • H04L27/2691—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation involving interference determination or cancellation
    • 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

Landscapes

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

Abstract

The invention discloses a multi-antenna OTFS (optical transmission system) modulation method and a system based on spatial modulation, wherein the method comprises the following steps: carrying out spatial modulation on an original information sequence to be transmitted to obtain a modulated symbol sequence and a transmitting antenna index sequence; arranging the symbol sequence of each transmitting antenna into a time delay-Doppler domain signal matrix to obtain an OTFS symbol block, and transforming the OTFS symbol block into a time domain signal matrix; performing time domain channel transmission on the time domain signal matrix according to the sending antenna index sequence; performing OTFS demodulation on the time domain signal matrix at a receiving end, and recovering the time domain signal matrix into a symbol matrix on a delay-Doppler domain; and carrying out maximum likelihood detection on the symbol matrix recovered on each time slot by combining the antenna index sequence and the modulated symbol sequence, and recovering the original information sequence. According to the invention, only one sending antenna is activated in each time slot to transmit data information, so that the problems of mutual interference and synchronization among the antennas can be effectively avoided, and the complexity of a multi-antenna system receiver can be reduced.

Description

Multi-antenna OTFS (optical transmission and frequency shift keying) modulation method and system based on spatial modulation
Technical Field
The invention belongs to the technical field of communication, and particularly relates to a multi-antenna OTFS (optical transmission and frequency conversion) modulation method and system based on spatial modulation.
Background
For next generation wireless systems, such as the latter 5G and 6G, how to obtain high reliability and high throughput data transmission has become a hot issue for the design of multicarrier signal transmission schemes. These schemes are expected to be expected to transmit efficiently in double-dispersion channels in high-speed mobile scenarios such as high-speed rail communication and inter-vehicle communication. Orthogonal Time Frequency Space (OTFS) modulation techniques are just multicarrier transmission schemes proposed for such high doppler channels. Compared with the Orthogonal Frequency Division Multiplexing (OFDM) scheme adopted by 4G and 5G at present, the OTFS adopts the delay-doppler domain to perform signal transmission and signal processing, can capture time shift and doppler shift in an actual physical channel, change a time-varying multipath channel into a time-invariant channel in the delay-doppler domain, can effectively estimate channel state information in the delay-doppler domain, and simplifies the design of a channel equalizer.
Currently, the development of OTFS technology is mainly in 4 directions: the method has the advantages of simplifying the structure of the OTFS system, reducing the detection complexity, researching the performance of the multi-antenna OTFS system and designing a high-efficiency channel estimation algorithm.
Research aiming at the MIMO (multiple input multiple output) -OTFS system mainly comprises the research of students such as M.K. Ramandanan on the vectorized derivation of the input-output relationship of the general MIMO-OTFS system in the article MIMO-OTFS in high-Doppler processing channels and Signal detection and channel estimation and the low complexity detection algorithm based on message passing. For the combination of specific MIMO technology and OTFS technology, there is currently also a study on STC-OTFS system performance in the article "Space-time coded OTFS modulation in high-Doppler channels" by scholars of r.m. A study on Space-Time coded OTFS modulation in high-Doppler channels combines Space-Time code (STC) with OTFS, and a simulation result shows that the STC-OTFS can obtain full diversity gain of Space, Time and frequency, and meanwhile, compared with a single-antenna system, the STC-OTFS has good bit error rate performance. However, the maximum spectral efficiency of the STC-OTFS system with full diversity can only be one symbol transmitted per slot, and the spectral efficiency is low.
Disclosure of Invention
In order to solve the above problems in the prior art, the present invention provides a method and a system for modulating a multi-antenna OTFS based on spatial modulation. The technical problem to be solved by the invention is realized by the following technical scheme:
one aspect of the present invention provides a multi-antenna OTFS modulation method based on spatial modulation, including:
carrying out spatial modulation on an original information sequence to be transmitted to obtain a modulated symbol sequence and a transmitting antenna index sequence;
arranging the symbol sequence of each transmitting antenna into a time delay-Doppler domain signal matrix, obtaining an OTFS symbol block and modulating the OTFS symbol block into a time domain signal matrix;
performing time domain channel transmission on the time domain signal matrix according to the transmitting antenna index sequence;
performing OTFS demodulation on the time domain signal matrix received by each receiving antenna at a receiving end, and recovering the time domain signal matrix into a symbol matrix on a delay-Doppler domain;
and carrying out maximum likelihood detection on the symbol matrix demodulated and recovered on each time slot by combining the antenna index sequence and the demodulated symbol sequence, and recovering the original information sequence.
In an embodiment of the present invention, spatially modulating an original information sequence to be transmitted to obtain a modulated information symbol sequence and a transmit antenna index sequence, includes:
converting an original information sequence to be transmitted into a binary bit sequence, grouping the binary bit sequence according to m bits as a group, and separating each group into m-length binary bit sequencessSignal bit vector sum length mlWhere m is the spectral efficiency of the modulation system and m is the spatial bit vector ofl＝log2Nt，NtM is the total number of transmit antennass＝m-ml；
For each packet length of msCarrying out constellation mapping on the signal bit vector to obtain a symbol after constellation mapping, and further obtaining a symbol sequence to be transmitted;
for each packet length of mlThe space bit vector is subjected to antenna index mapping to obtain a sending antenna index and further obtain a sending antenna index sequence, wherein the sending antenna index sequence is used for determining an activated antenna of each time slot and further determining a symbol sequence on each sending antenna.
In an embodiment of the present invention, arranging the symbol sequence of each transmit antenna into a delay-doppler domain signal matrix, obtaining an OTFS symbol block and transforming the OTFS symbol block into a time domain signal matrix, includes:
setting OTFS (optical transmission system) modulation system parameters: setting the number of the sub-carriers as M and the number of the multi-carrier symbols as N;
arranging the symbol sequence of each transmitting antenna into an MXN time delay-Doppler domain signal matrix to form an OTFS symbol block;
and performing ISFFT (inverse fast Fourier transform) on the OTFS symbol block on each transmitting antenna, and performing Heisenberg transform to obtain an M multiplied by N time domain signal matrix.
In an embodiment of the present invention, performing time domain channel transmission on the time domain signal matrix according to the transmit antenna index sequence includes:
converting the M multiplied by N time domain signal matrix on each transmitting antenna into MN multiplied by 1 time domain signal vectors through parallel-serial conversion;
and acquiring a sending antenna index and activating a corresponding antenna in a time domain channel according to the sending antenna index so as to transmit the time domain signal vector.
In an embodiment of the present invention, performing OTFS demodulation on a time domain signal matrix received on each receiving antenna at a receiving end to recover to a symbol matrix in a delay-doppler domain, includes:
converting the time domain signal vector received on each receiving antenna into an M multiplied by N time domain signal matrix in a serial-to-parallel mode;
and performing Wigner transformation and SFFT transformation on the M multiplied by N time domain signal matrix on each receiving antenna, thereby restoring the received signals of each receiving antenna into an M multiplied by N time delay-Doppler domain symbol matrix.
In an embodiment of the present invention, performing maximum likelihood detection on the symbol matrix demodulated and recovered at each time slot in combination with the antenna index sequence and the demodulated symbol sequence to recover the original information sequence, includes:
performing parallel-serial conversion on the recovered M multiplied by N time delay-Doppler domain signal matrix on each receiving antenna to convert the M multiplied by N time delay-Doppler domain signal matrix into MN multiplied by 1 signal vectors on a time delay-Doppler domain;
and performing joint maximum likelihood detection on the antenna index sequence and the demodulated symbol sequence according to the symbol vector consisting of the symbols received by different receiving antennas on each time slot, recovering the transmission information sequence on each time slot, and further recovering the whole original information sequence.
Another aspect of the present invention provides a multi-antenna OTFS modulation system based on spatial modulation, including:
the spatial modulation module is used for carrying out spatial modulation on an information sequence to be transmitted to obtain a modulated symbol sequence and a transmitting antenna index sequence;
the OTFS modulation module is used for arranging the symbol sequence of each transmitting antenna into a time delay-Doppler domain signal matrix, obtaining an OTFS symbol block and modulating the OTFS symbol block into a time domain signal matrix;
the time domain channel module is used for carrying out time domain channel transmission on the time domain signal matrix according to the sending antenna index sequence;
the OTFS demodulation module is used for performing OTFS demodulation on the time domain signal matrix received on each receiving antenna at the receiving end and recovering the time domain signal matrix into a symbol matrix on a time delay-Doppler domain;
and the signal detection module is used for carrying out maximum likelihood detection on the symbol matrix which is demodulated and recovered on each time slot in combination with the antenna index sequence and the demodulated symbol sequence to recover the original information sequence.
In one embodiment of the present invention, the spatial modulation module includes:
a signal separation unit for converting the original information sequence to be transmitted into binary bit sequence, and grouping the binary bit sequence according to each group of m bits, wherein each group is separated into m bitssOf a signal bit vector and length mlWhere m is the spectral efficiency of the modulation system and m is the spatial bit vector ofl＝log2Nt，NtM is the total number of transmit antennass＝m-ml；
A constellation mapping unit for mapping length m in each packetsCarrying out constellation mapping on the signal bit vector to obtain a symbol after constellation mapping, and further obtaining a symbol sequence to be transmitted;
an antenna index mapping unit for mapping the length of m in each packetlThe space bit vector is subjected to antenna index mapping to obtain a sending antenna index and further obtain a sending antenna index sequence, wherein the sending antenna index sequence is used for determining an activated antenna of each time slot and further determining a symbol sequence on each sending antenna.
In one embodiment of the present invention, the OTFS modulation module includes:
an OTFS symbol block generating unit, configured to arrange the symbol sequence of each transmitting antenna into an mxn time delay-doppler domain signal matrix to form an OTFS symbol block;
an ISFFT transforming unit, which is used for carrying out ISFFT transformation on the OTFS symbol block on each transmitting antenna;
and the Heisenberg transformation unit is used for carrying out Heisenberg transformation on the OTFS symbol block after ISFFT transformation to obtain an M multiplied by N time domain signal matrix.
In one embodiment of the present invention, the time domain channel module includes:
the parallel-serial conversion unit is used for converting the M multiplied by N time domain signal matrix into an MN multiplied by 1 dimensional time domain signal vector;
and the antenna array unit is used for acquiring a sending antenna index and activating a corresponding antenna in a time domain channel according to the sending antenna index so as to transmit the time domain signal vector.
Compared with the prior art, the invention has the beneficial effects that:
1. the multi-antenna OTFS modulation method based on spatial modulation applies the spatial modulation technology to an OTFS modulation system, improves the spectrum efficiency of the system, reduces the bit error rate by utilizing the high spectrum efficiency of the spatial modulation and the diversity gain of the antenna and carrying information through the antenna index, can well resist high Doppler simultaneously, and has good robustness in high-speed movement and high-frequency communication scenes.
2. The multi-antenna OTFS modulation method and the system based on spatial modulation of the invention activate one sending antenna to transmit data information, can effectively avoid the problems of mutual interference and synchronization between the antennas, and can reduce the complexity of a system receiver.
The present invention will be described in further detail with reference to the accompanying drawings and examples.
Drawings
Fig. 1 is a flowchart of a multi-antenna OTFS modulation method based on spatial modulation according to an embodiment of the present invention;
fig. 2 is a schematic process diagram of a multi-antenna OTFS modulation method based on spatial modulation according to an embodiment of the present invention;
fig. 3 is a diagram illustrating spatial mapping of a spatial modulation signal in a multi-antenna OTFS modulation method based on spatial modulation according to an embodiment of the present invention;
fig. 4 is a schematic block diagram of a multi-antenna OTFS modulation system based on spatial modulation according to an embodiment of the present invention;
fig. 5 is a graph comparing simulation results of the method of the embodiment of the present invention and the existing STC-OTFS method.
Detailed Description
To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined object, a method and a system for modulating an OTFS based on spatial modulation according to the present invention are described in detail below with reference to the accompanying drawings and the detailed description.
The foregoing and other technical matters, features and effects of the present invention will be apparent from the following detailed description of the embodiments, which is to be read in connection with the accompanying drawings. The technical means and effects of the present invention adopted to achieve the predetermined purpose can be more deeply and specifically understood through the description of the specific embodiments, however, the attached drawings are provided for reference and description only and are not used for limiting the technical scheme of the present invention.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or device that comprises a list of elements does not include only those elements but may include other elements not expressly listed. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of additional like elements in the article or device in which the element is included.
Example one
Referring to fig. 1, fig. 1 is a flowchart of a multi-antenna OTFS modulation method based on spatial modulation according to an embodiment of the present invention. The multi-antenna OTFS modulation method comprises the following steps:
s1: and carrying out spatial modulation on an original information sequence to be transmitted to obtain a modulated symbol sequence and a transmitting antenna index sequence.
Specifically, step S1 includes:
s11: converting an original information sequence to be transmitted into a binary bit sequence, grouping the binary bit sequence according to m bits as a group, and separating each group into m bits in lengthsOf a signal bit vector and length mlWhere m is the spectral efficiency of the modulation system and m is the spatial bit vector ofl＝log2Nt，NtM is the total number of transmit antennass＝m-ml；
S12: for each packet with length msCarrying out constellation mapping on the signal bit vector to obtain a symbol after constellation mapping, and further obtaining a symbol sequence to be transmitted;
s13: for each packet length of mlThe space bit vector is subjected to antenna index mapping to obtain a sending antenna index and further obtain a sending antenna index sequence, wherein the sending antenna index sequence is used for determining an activated antenna of each time slot and further determining a symbol sequence on each sending antenna.
S2: arranging the symbol sequence of each transmitting antenna into a time delay-Doppler domain signal matrix, obtaining an OTFS symbol block and modulating the OTFS symbol block into a time domain signal matrix.
Specifically, step S2 includes:
s21: setting OTFS modulation system parameters: setting the number of subcarriers as M, the number of multicarrier symbols as N, and an OTFS symbol block as an M multiplied by N matrix formed by MN symbol sequences;
s22: arranging the symbol sequence of each transmitting antenna into an MXN time delay-Doppler domain signal matrix to form an OTFS symbol block;
s23: and performing ISFFT (inverse fast Fourier transform) on the OTFS symbol block on each transmitting antenna, and performing Heisenberg transform to obtain an M multiplied by N time domain signal matrix.
S3: and carrying out time domain channel transmission on the time domain signal matrix according to the transmitting antenna index sequence.
Specifically, an M × N time domain signal matrix on each transmit antenna is converted into an MN × 1 time domain signal vector by parallel-to-serial conversion; and activating the corresponding antenna in the time domain channel according to the sending antenna index so as to transmit the time domain signal vector.
S4: and performing OTFS demodulation on the time domain signal matrix received by each receiving antenna at a receiving end, and recovering the time domain signal matrix into a symbol matrix on a delay-Doppler domain.
Specifically, a time domain signal vector received on each receiving antenna is converted into an M × N time domain signal matrix by serial-to-parallel conversion; and then carrying out Wigner transformation and SFFT transformation on the M multiplied by N time domain signal matrix on each receiving antenna, thereby restoring the received signals of each receiving antenna into an M multiplied by N time delay-Doppler domain symbol matrix.
S5: and carrying out maximum likelihood detection on the symbol matrix demodulated and recovered on each time slot by combining the antenna index sequence and the demodulated symbol sequence, and recovering the original information sequence.
Specifically, parallel-serial conversion is carried out on an MXN time delay-Doppler domain signal matrix recovered on each receiving antenna, and the MXN time delay-Doppler domain signal matrix is converted into an MN X1 signal vector on a time delay-Doppler domain; and then carrying out joint maximum likelihood detection on the antenna index sequence and the demodulated symbol sequence according to the symbol vector consisting of the symbols received by different receiving antennas on each time slot, recovering the transmission information sequence on each time slot, and further recovering the whole information sequence.
In this embodiment, the receiving end performs maximum likelihood detection on the symbol matrix recovered from demodulation in each timeslot by using an optimal detection algorithm, i.e., maximum likelihood sequence detection, in combination with the antenna index sequence and the modulated symbol sequence, and then performs antenna demapping and signal demapping to obtain the entire transmitted information sequence.
The multi-antenna OTFS modulation method based on spatial modulation in the embodiment applies the spatial modulation technology to an OTFS modulation system, improves the spectrum efficiency of the system by utilizing the high spectrum efficiency of the spatial modulation and the diversity gain of the antenna and carrying information through the antenna index, reduces the bit error rate, can well resist high Doppler simultaneously, and has good robustness in high-speed movement and high-frequency communication scenes.
Example two
On the basis of the above embodiments, the present embodiment provides another multi-antenna OTFS modulation method based on spatial modulation. Referring to fig. 2, the method for modulating the multi-antenna OTFS of the present embodiment includes:
(1) number of spatial bits required for spatial allocation to transmit antennas: setting the total number of transmitting antennas NtPower of 2, for the total number of transmit antennas NtCarrying out logarithm operation to obtain the space bit number ml＝log2Nt(ii) a Setting the activation probability of each transmit antenna to be equal, one space bit vector and one antenna index form a one-to-one mapping.
In this embodiment, the total number of transmission antennas N is settIs 2, the number of spatial bits is ml＝log2Nt1. I.e., spatial bit 0 corresponds to antenna index 1 and spatial bit 1 corresponds to antenna index 2.
(2) Allocating the required signal bit number to the signal space mapping: setting the spectrum efficiency to be realized by the system as m to 3, and calculating the bit number m required by signal space mapping by using a spectrum efficiency formulas＝m-ml＝2。
(3) Setting parameters of an OTFS modulation module: setting the number of subcarriers modulated by the OTFS to be M-2, and representing a time delay dimension; the number of the multicarrier symbols is N-2, and the Doppler dimension is represented; an OTFS symbol block is formed by a 2 × 2 matrix containing M × N ═ 4 modulation symbols.
(4) Grouping information sequences to be transmitted:
specifically, an original information sequence to be transmitted is represented by a binary bit sequence, and then every m bit sequences in the binary bit sequence are separated, that is, each group comprises m bit sequences, and each group is separated into m bit sequencessSignal bit vector sum of length mlSpace ratio ofA bit vector.
In this embodiment, every 3 bits in the binary bit vector are divided into a group, and the group of bits is separated into a signal bit vector with a length of 2 and a spatial bit vector with a length of 1, as shown in fig. 2.
Further, please refer to fig. 3, fig. 3 is a diagram illustrating spatial mapping of a spatial modulation signal in a multi-antenna OTFS modulation method based on spatial modulation according to an embodiment of the present invention. Specifically, fig. 3 shows an example of spatial modulation, which is to firstly group binary bit sequences into m-3 groups to obtain respective groups, and then separate binary bit vectors in each group into m-length groupslAntenna index bit sum m of 1sFor 2 signal vector bits, as shown in the shaded portion, in the first time slot, 011 is separated into 0 and 11 to represent an antenna index bit and a signal vector bit, respectively, and then the antenna index bit 0 is mapped to an antenna index 1 and the signal vector bit 11 is mapped to a complex number-1-j according to a mapping table. When the first transmitting antenna is activated in the 1 st time slot, the transmitting vector V of the first time slot1Indicating that the first antenna transmits a signal-1-j and the second antenna transmits a value of 0. In the figure x1And x2Representing the sequence of transmitted symbols on the first antenna and the second antenna.
(5) And mapping the grouped signal bit vector and the space bit vector respectively.
Specifically, a signal bit vector with the length of 2 and a space bit vector with the length of 1 are mapped respectively, the signal bit vector is mapped into a QPSK (Quadrature Phase Shift Keying) constellation point by a constellation mapping method, and a symbol sequence after constellation mapping is obtained; for each packet length of mlAnd performing antenna index mapping on the space bit vector of 1 to obtain a transmission antenna index sequence, wherein the transmission antenna index sequence is used for determining an activated antenna of each time slot and further determining a symbol sequence on each transmission antenna.
(6) Constructing an OTFS symbol block: arranging the symbol sequence of each transmitting antenna after constellation mapping into a 2 x 2 time delay-Doppler domain signal matrix, namely an OTFS symbol block.
(7) OTFS modulation: and performing ISFFT (inverse fast Fourier transform) on the OTFS symbol block, and performing Heisenberg transform on the OTFS symbol block to obtain a 2 x 2 time domain signal matrix.
(8) Channel transmission: converting the 2 × 2 time domain signal matrix into a 4 × 1 time domain signal vector through parallel-to-serial conversion, then determining a transmitting antenna corresponding to each information symbol according to the transmitting antenna index in step (5), and activating the transmitting antenna to transmit the time domain signal, where the space bit vector information is included in the index of the transmitting antenna.
(9) Receiving time domain signal vector by receiving antenna: the receiving end converts the time domain received signal vector into a 2 x 2 time domain received signal matrix through serial-to-parallel conversion.
(10) OTFS demodulation: and firstly carrying out Wigner transformation on the 2 x 2 time domain received signal matrix, and then carrying out SFFT transformation to obtain the 2 x 2 received signal matrix on the delay-Doppler domain.
(11) Maximum likelihood detection in the delay-doppler domain: the receiving end adopts the optimal detection algorithm, namely maximum likelihood sequence detection, and carries out the joint maximum likelihood detection of the antenna index sequence and the demodulated symbol sequence according to the symbol vector consisting of the symbols received by different receiving antennas on each time slot, thereby recovering the transmission information sequence on each time slot and further recovering the whole original information sequence.
EXAMPLE III
On the basis of the above embodiments, the present embodiment provides a multi-antenna OTFS modulation system based on spatial modulation. Referring to fig. 4, fig. 4 is a schematic block diagram of a multi-antenna OTFS modulation system based on spatial modulation according to an embodiment of the present invention. The signal modulation system includes:
the spatial modulation module 1 is configured to perform spatial modulation on an information sequence to be transmitted to obtain a modulated symbol sequence and a transmit antenna index sequence;
the OTFS modulation module 2 is used for arranging the symbol sequence of each transmitting antenna into a time delay-Doppler domain signal matrix, obtaining an OTFS symbol block and modulating the OTFS symbol block into a time domain signal matrix;
a time domain channel module 3, configured to perform time domain channel transmission on the time domain signal matrix according to the transmit antenna index sequence;
the OTFS demodulation module 4 is used for carrying out OTFS demodulation on the time domain signal matrix received on each receiving antenna at the receiving end and recovering the time domain signal matrix as a symbol matrix on a time delay-Doppler domain;
and the signal detection module 5 is configured to perform maximum likelihood detection on the symbol matrix demodulated and recovered in each time slot in combination with the antenna index sequence and the modulated symbol sequence, and recover the original information sequence.
Further, the spatial modulation module 1 of the present embodiment includes:
a signal separation unit for converting the original information sequence to be transmitted into a binary bit sequence and grouping the binary bit sequence according to a group of m bits, each group being separated into m bits in lengthsOf a signal bit vector and length mlWhere m is the spectral efficiency of the modulation system and m is the spatial bit vector ofl＝log2Nt，NtM is the total number of transmit antennass＝m-ml；
A constellation mapping unit for mapping length m in each packetsPerforming constellation mapping on the signal bit vector to obtain a symbol sequence after constellation mapping;
an antenna index mapping unit for mapping the length of m in each packetlThe space bit vector of (a) is subjected to antenna index mapping to obtain a transmitting antenna index sequence, wherein the transmitting antenna index sequence is used for determining an activated antenna of each time slot, and further determining a symbol sequence on each transmitting antenna.
Further, the OTFS modulation module 2 includes an OTFS symbol block generating unit, an ISFFT transforming unit, and a Heisenberg transforming unit, where the OTFS symbol block generating unit is configured to arrange the symbol sequence of each transmitting antenna into an mxn time delay-doppler domain signal matrix to form an OTFS symbol block; the ISFFT conversion unit is used for carrying out ISFFT conversion on the OTFS symbol block on each transmitting antenna; and the Heisenberg transformation unit is used for performing Heisenberg transformation on the OTFS symbol block after ISFFT transformation to obtain an M multiplied by N time domain signal matrix.
Further, the time domain channel module 3 of this embodiment includes a parallel-to-serial conversion unit and an antenna array unit, where the parallel-to-serial conversion unit is configured to convert the M × N time domain signal matrix into an MN × 1 time domain signal vector; the antenna array unit is used for acquiring a sending antenna index and activating a corresponding antenna in a time domain channel according to the sending antenna index so as to transmit the time domain signal vector.
The OTFS modulation module 4 of this embodiment includes a serial-to-parallel conversion unit, a Wigner conversion unit, and an SFFT conversion unit, where the serial-to-parallel conversion unit is configured to convert a received MN × 1 time domain signal vector into an M × N time domain signal matrix, where M is the number of subcarriers and N is the number of multicarrier symbols; the Wigner transformation unit is used for transforming the M multiplied by N time domain signal matrix into a signal matrix on a time-frequency domain; the SFFT unit is used for transforming the signal matrix on the time-frequency domain into a symbol matrix on the time delay-Doppler domain.
Further, the signal detection module 5 includes a signal conversion unit and a maximum likelihood detection unit, where the signal conversion unit is configured to perform parallel-to-serial conversion on the mxn delay-doppler domain signal matrix recovered on each receiving antenna, and convert the M × N delay-doppler domain signal matrix into an MN × 1 signal vector in the delay-doppler domain; the maximum likelihood detection unit is used for carrying out the joint maximum likelihood detection of the antenna index sequence and the modulated symbol sequence according to the symbol vector consisting of the symbols received by different receiving antennas on each time slot, recovering the transmission information sequence on each time slot and further recovering the whole original information sequence.
The multi-antenna OTFS modulation system based on spatial modulation applies the spatial modulation technology to the OTFS modulation system, utilizes the high spectral efficiency of the spatial modulation and the diversity gain of the antenna, and carries information through the antenna index, so that the spectral efficiency of the system is improved, the bit error rate is reduced, high Doppler can be resisted well, and the multi-antenna OTFS modulation system has good robustness in high-speed movement and high-frequency communication scenes. The system adopts the mode of activating one sending antenna to transmit data information, can effectively avoid the problems of mutual interference and synchronization between the antennas, and can reduce the detection complexity of the system.
The technical effects of the signal modulation method and system based on SM-OTFS in the embodiment of the invention are explained by combining simulation experiments as follows:
1. simulation conditions and contents:
in the embodiment of the present invention, Visual Studio2013 refers to the simulation parameters in table 1, and performs comparison simulation of the bit error rate of transmission under a windows10 system on the existing STC-OTFS method and the method of the embodiment of the present invention, where a mapping relationship between a signal bit vector and a modulation constellation point is shown in table 2, a mapping relationship between a space bit vector and an antenna index is shown in table 3, and the result is shown in fig. 5:
TABLE 1 simulation parameter Table
Parameter(s) Numerical value
Carrier frequency (GHz) 4
Subcarrier spacing (kHz) 3.75
Number of subcarriers M 2
Number of multicarrier symbols N 2
Multiple antenna configuration 2T4R
Constellation modulation QPSK、8PSK
Channel estimation Ideal for
The number of paths P is 2, (τ)i,υi) (0,0)，(1,1)
Maximum speed (km/h) 506.2
Receiver with a plurality of receivers Maximum likelihood sequence detection
TABLE 2 mapping table of signal bit vectors and modulation constellation points
Binary signal bit vector QPSK modulation symbol
00 +1+j
01 -1+j
10 +1-j
11 -1-j
Table 3 mapping table of space bit vector and transmit antenna index
Binary space bit vector Antenna index
0 1
1 2
2. And (3) simulation result analysis:
referring to fig. 5, fig. 5 is a graph comparing simulation results of the method of the present invention and the existing STC-OTFS method, wherein the horizontal axis represents the signal-to-noise ratio of the transmission channel, and the vertical axis represents the bit error rate of each transmission. An "SM-OTFS-QPSK" line represents a bit error rate curve of the SM-OTFS method according to the embodiment of the present invention under QPSK modulation, an "STC-OTFS-8 PSK" line represents a bit error rate curve of the existing STC-OTFS method under 8PSK modulation, and an "SM-OTFS-8 PSK" line represents a bit error rate curve of the SM-OTFS method according to the embodiment of the present invention under 8PSK modulation.
As can be seen from fig. 5, under a 2 × 4 antenna configuration, the SM-OTFS method according to the embodiment of the present invention has a spectral efficiency of 3 bits per timeslot for QPSK modulation and 8PSK modulation. At a bit error rate of 10-4Compared with the existing transmission scheme STC-OTFS-8PSK, the SM-OTFS method of the embodiment of the invention can obtain the performance gain close to 9dB in a QPSK modulation communication system. Description on the same dayCompared with the existing STC-OTFS method, the SM-OTFS method provided by the embodiment of the invention can reduce the bit error rate under the condition of line configuration and the same spectral efficiency, and is mainly realized by using lower-order constellation mapping, and in addition, the method provided by the embodiment of the invention can effectively avoid multi-antenna interference and obtain better bit error rate performance by only activating one antenna in each time slot.
In addition, under the same antenna configuration of 2 × 4, the SM-OTFS method and the existing STC-OTFS method in the embodiment of the present invention both use 8PSK constellation mapping, so that the spectral efficiency of the SM-OTFS-8PSK in the embodiment of the present invention is 4 bits per slot, and the spectral efficiency of the existing STC-OTFS-8PSK transmission method is 3 bits per slot. As can be seen from fig. 5, the SM-OTFS-8PSK in the embodiment of the present invention has a higher spectral efficiency than the STC-OTFS-8PSK in the conventional transmission method, and the bit error rate performance of the SM-OTFS-8PSK is better than the bit error rate performance of the STC-OTFS-8 PSK.
To sum up, the embodiment of the present invention applies a spatial modulation technique to an OTFS modulation system based on spatial modulation of multiple antennas OTFS, and utilizes high spectral efficiency of spatial modulation and diversity gain of antennas to carry information through antenna indexes, thereby improving spectral efficiency of the system, reducing bit error rate, and simultaneously being capable of well resisting high doppler, and having good robustness in high-speed mobile and high-frequency communication scenarios. The signal modulation method and the system can effectively avoid the problems of mutual interference and synchronization between the antennas by activating one transmitting antenna to transmit data information, and can reduce the detection complexity of the system.
The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.

Claims (10)

1. A multi-antenna OTFS modulation method based on spatial modulation is characterized by comprising the following steps:
carrying out spatial modulation on an original information sequence to be transmitted to obtain a modulated symbol sequence and a transmitting antenna index sequence;
arranging the symbol sequence of each transmitting antenna into a time delay-Doppler domain signal matrix, obtaining an OTFS symbol block and modulating the OTFS symbol block into a time domain signal matrix;
performing time domain channel transmission on the time domain signal matrix according to the sending antenna index sequence;
performing OTFS demodulation on a time domain signal matrix received on each receiving antenna at a receiving end, and recovering the time domain signal matrix into a symbol matrix on a delay-Doppler domain;
and carrying out maximum likelihood joint detection on the symbol matrix demodulated and recovered on each time slot by combining the antenna index sequence and the demodulated symbol sequence, and recovering the original information sequence.
2. The multi-antenna OTFS modulation method based on spatial modulation according to claim 1, wherein the method for spatially modulating the original information sequence to be transmitted to obtain the modulated information symbol sequence and the transmitted antenna index sequence comprises:
converting an original information sequence to be transmitted into a binary bit sequence, grouping the binary bit sequence according to m bits as a group, and separating each group into m-length binary bit sequencessSignal bit vector sum length mlWhere m is the spectral efficiency of the modulation system and m is the spatial bit vector ofl＝log2Nt，NtM is the total number of transmit antennass＝m-ml；
For each packet length of msThe signal bit vector is subjected to constellation mapping to obtain a symbol after constellation mapping, and then a symbol sequence to be transmitted is obtained;
for each packet length of mlThe space bit vector is subjected to antenna index mapping to obtain a sending antenna index, and then an antenna index sequence is obtained, wherein the sending antenna index sequence is used for determining an activated antenna of each time slot, and further determining a symbol sequence on each sending antenna.
3. The method of claim 1, wherein the arranging the symbol sequence of each transmitting antenna into a delay-doppler domain signal matrix, obtaining the OTFS symbol block and transforming the OTFS symbol block into a time domain signal matrix comprises:
setting OTFS modulation system parameters: setting the number of subcarriers as M and the number of multicarrier symbols as N;
arranging the symbol sequence of each transmitting antenna into an MXN time delay-Doppler domain signal matrix to form an OTFS symbol block;
and performing ISFFT (inverse fast Fourier transform) on the OTFS symbol block on each transmitting antenna, and performing Heisenberg transform to obtain an M multiplied by N time domain signal matrix.
4. The method of claim 3, wherein the time-domain channel transmission of the time-domain signal matrix according to the transmit antenna index sequence comprises:
converting the M multiplied by N time domain signal matrix on each transmitting antenna into MN multiplied by 1 time domain signal vectors through parallel-serial conversion;
and acquiring a sending antenna index and activating a corresponding antenna in a time domain channel according to the sending antenna index so as to transmit the time domain signal vector.
5. The multi-antenna OTFS modulation method based on spatial modulation of claim 3, wherein the OTFS demodulation is performed on the time domain signal matrix received on each receiving antenna at the receiving end to recover the symbol matrix on the time delay-Doppler domain, and the method comprises:
converting the time domain signal vector received on each receiving antenna into an M multiplied by N time domain signal matrix in a serial-parallel mode;
and performing Wigner transformation and SFFT transformation on the M multiplied by N time domain signal matrix on each receiving antenna, thereby restoring the received signals of each receiving antenna into an M multiplied by N time delay-Doppler domain symbol matrix.
6. The method of claim 5, wherein the maximum likelihood detection is performed on the symbol matrix recovered by demodulation in each time slot in combination with the antenna index sequence and the demodulated symbol sequence to recover the original information sequence, and the method comprises:
performing parallel-serial conversion on the recovered M multiplied by N time delay-Doppler domain signal matrix on each receiving antenna to convert the M multiplied by N time delay-Doppler domain signal matrix into MN multiplied by 1 signal vectors on a time delay-Doppler domain;
and performing joint maximum likelihood detection on the antenna index sequence and the demodulated symbol sequence according to the symbol vector consisting of the symbols received by different receiving antennas on each time slot, recovering the transmission information sequence on each time slot, and further recovering the whole original information sequence.
7. A multi-antenna OTFS modulation system based on spatial modulation, comprising:
the spatial modulation module is used for carrying out spatial modulation on an information sequence to be transmitted to obtain a modulated symbol sequence and a transmitting antenna index sequence;
the OTFS modulation module is used for arranging the symbol sequence of each transmitting antenna into a time delay-Doppler domain signal matrix, obtaining an OTFS symbol block and modulating the OTFS symbol block into a time domain signal matrix;
a time domain channel module, configured to perform time domain channel transmission on the time domain signal matrix according to the transmit antenna index sequence;
the OTFS demodulation module is used for performing OTFS demodulation on the time domain signal matrix received on each receiving antenna at the receiving end and recovering the time domain signal matrix into a symbol matrix on a time delay-Doppler domain;
and the signal detection module is used for carrying out maximum likelihood detection on the symbol matrix demodulated and recovered on each time slot in combination with the antenna index sequence and the demodulated symbol sequence to recover the original information sequence.
8. The spatial modulation based multi-antenna OTFS modulation system according to claim 7, wherein the spatial modulation module comprises:
a signal separation unit for converting the original information sequence to be transmitted into binary bit sequence, and grouping the binary bit sequence according to each group of m bits, wherein each group is separated into m bitssSignal bit vector sum length mlWhere m is the spectral efficiency of the modulation system and m is the spatial bit vector ofl＝log2Nt，NtM is the total number of transmit antennass＝m-ml；
A constellation mapping unit for mapping the length m of each packetsCarrying out constellation mapping on the signal bit vector to obtain a symbol after constellation mapping, and further obtaining a symbol sequence to be transmitted;
an antenna index mapping unit for mapping the length of m in each packetlThe space bit vector is subjected to antenna index mapping to obtain a sending antenna index and further obtain a sending antenna index sequence, wherein the sending antenna index sequence is used for determining an activated antenna of each time slot and further determining a symbol sequence on each sending antenna.
9. The spatial modulation based multi-antenna OTFS modulation system according to claim 7, wherein the OTFS modulation module comprises:
an OTFS symbol block generating unit, configured to arrange the symbol sequence of each transmit antenna into an mxn time delay-doppler domain signal matrix to form an OTFS symbol block, where the OTFS modulation system parameters are: the number of subcarriers is M, and the number of multicarrier symbols is N;
an ISFFT transforming unit, which is used for carrying out ISFFT transformation on the OTFS symbol block on each transmitting antenna;
and the Heisenberg transformation unit is used for carrying out Heisenberg transformation on the OTFS symbol block after ISFFT transformation to obtain an M multiplied by N time domain signal matrix.
10. The spatial modulation based multi-antenna OTFS modulation system according to claim 9, wherein the time domain channel module comprises:
the parallel-serial conversion unit is used for converting the M multiplied by N time domain signal matrix into an MN multiplied by 1 dimensional time domain signal vector;
and the antenna array unit is used for acquiring a sending antenna index and activating a corresponding antenna in a time domain channel according to the sending antenna index so as to transmit the time domain signal vector.
CN202110918843.XA 2021-08-11 2021-08-11 Multi-antenna OTFS (optical transmission and frequency shift keying) modulation method and system based on spatial modulation Active CN113810325B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110918843.XA CN113810325B (en) 2021-08-11 2021-08-11 Multi-antenna OTFS (optical transmission and frequency shift keying) modulation method and system based on spatial modulation

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110918843.XA CN113810325B (en) 2021-08-11 2021-08-11 Multi-antenna OTFS (optical transmission and frequency shift keying) modulation method and system based on spatial modulation

Publications (2)

Publication Number Publication Date
CN113810325A CN113810325A (en) 2021-12-17
CN113810325B true CN113810325B (en) 2022-07-12

Family

ID=78893464

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110918843.XA Active CN113810325B (en) 2021-08-11 2021-08-11 Multi-antenna OTFS (optical transmission and frequency shift keying) modulation method and system based on spatial modulation

Country Status (1)

Country Link
CN (1) CN113810325B (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114553268B (en) * 2022-02-23 2022-12-27 广东工业大学 MIMO-based incoherent LoRa communication system
CN114745246B (en) * 2022-04-06 2023-11-17 山东大学 Working method of orthogonal time-frequency space modulation system based on orthogonal space modulation
CN114944896B (en) * 2022-04-08 2023-10-24 江苏科技大学 Index modulation OTFS communication system and method based on Y-type network
CN115051894B (en) * 2022-06-10 2024-02-06 西安电子科技大学 OTFS system symbol detection method based on serial interference elimination
CN115174335A (en) * 2022-07-19 2022-10-11 西安电子科技大学 OTFS (optical transport File System) secure transmission method based on interleaving and replacing mechanism
CN115442189B (en) * 2022-08-23 2024-05-14 成都中科微信息技术研究院有限公司 Multi-antenna channel estimation method, medium and device suitable for time-frequency space domain
CN116192575B (en) * 2022-12-28 2023-09-29 中山大学 Time domain sparse block LMMSE channel equalization method and system for OTFS-MIMO diversity multiplexing

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112202479A (en) * 2020-08-19 2021-01-08 北京邮电大学 Low-complexity signal detection method for MIMO-orthogonal time-frequency space system

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011158496A1 (en) * 2010-06-17 2011-12-22 パナソニック株式会社 Pre-coding method and transmitter
WO2019113046A1 (en) * 2017-12-04 2019-06-13 Cohere Technologies, Inc. Implementation of orthogonal time frequency space modulation for wireless communications
CN111884975B (en) * 2020-07-17 2021-05-18 北京理工大学 Index modulation and demodulation method and system based on time delay-Doppler domain
CN112929316B (en) * 2021-01-25 2022-08-12 南京邮电大学 Interleaved time-frequency multi-access modulation and demodulation method and device based on OTFS modulation

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112202479A (en) * 2020-08-19 2021-01-08 北京邮电大学 Low-complexity signal detection method for MIMO-orthogonal time-frequency space system

Also Published As

Publication number Publication date
CN113810325A (en) 2021-12-17

Similar Documents

Publication Publication Date Title
CN113810325B (en) Multi-antenna OTFS (optical transmission and frequency shift keying) modulation method and system based on spatial modulation
CN106357311B (en) Detection method of MIMO-OFDM system based on carrier index modulation
CN100553186C (en) OFDM channel estimating and multiple transmit antennas are followed the tracks of
CN101496332B (en) The method and apparatus of multicarrier MIMO channel performance is improved with Hadamard transform
CN106453190A (en) Multi-user sub-carrier index modulation orthogonal frequency-division multiplexing (SIM-OFDM) transmission method
CN106161328B (en) The detection method of MIMO-OFDM system based on carrier index modulation
CN101127532B (en) Restraint method and system for mutual interference of orthogonal frequency division multiplexing communication carrier frequency
CN1325198A (en) Multi-input multi-output orthogonal frequency-division multiplexing system
CN111431617B (en) Asymmetric amplitude limiting light OFDM-IM modulation method for wireless optical communication
CN105591717A (en) Low-complexity detection method for MIMO-OFDM system with subcarrier index modulation
CN110830089B (en) Space frequency index modulation transmission method
CN104618082A (en) Multi-antenna SIM-OFDM multi-carrier type wireless transmission method
CN109347526B (en) IM-OFDM signal processing method for Internet of vehicles
CN108234102A (en) A kind of SM-GFDM systems with low complex degree detection algorithm
CN101141167B (en) Single carrier frequency domain equalization method and system in DFT-CDMA system
CN107302419A (en) A kind of low complex degree detection method for MIMO ofdm systems
CN102651727B (en) Incoherence detection method used in spatial modulation-orthogonal frequency division multiplexing (SM-OFDM) system of a plurality of antennas
CN112636832B (en) Efficient visible light communication system working method based on carrier index modulation
CN101771644A (en) Joint detection and soft decision decoding-based signal receiving method
CN107979558A (en) A kind of iteration detection method of the double fluid CE-OFDM systems based on width phase demodulator
CN112866167A (en) Generalized zero padding three-mode OFDM index modulation algorithm and system
CN101783722B (en) Transmission method and device for virtual MIMO
CN1838655A (en) MIMO-OFDM receiver
CN102694587B (en) Non-coherent detection method used in SM-OFDM (spatially-multiplexed-orthogonal frequency-division multiplexing) system
CN108234368A (en) A kind of high spectrum effect safety truncates OFDM transfer method

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