WO2018076773A1 - 基于重叠复用的译码方法、装置及调制解调方法和系统 - Google Patents

基于重叠复用的译码方法、装置及调制解调方法和系统 Download PDF

Info

Publication number
WO2018076773A1
WO2018076773A1 PCT/CN2017/091964 CN2017091964W WO2018076773A1 WO 2018076773 A1 WO2018076773 A1 WO 2018076773A1 CN 2017091964 W CN2017091964 W CN 2017091964W WO 2018076773 A1 WO2018076773 A1 WO 2018076773A1
Authority
WO
WIPO (PCT)
Prior art keywords
decoding
radius
ball
envelope waveform
modulation
Prior art date
Application number
PCT/CN2017/091964
Other languages
English (en)
French (fr)
Inventor
刘若鹏
季春霖
刘子红
张莎莎
Original Assignee
深圳超级数据链技术有限公司
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 深圳超级数据链技术有限公司 filed Critical 深圳超级数据链技术有限公司
Publication of WO2018076773A1 publication Critical patent/WO2018076773A1/zh

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
    • H04L1/0045—Arrangements at the receiver end
    • H04L1/0047—Decoding adapted to other signal detection operation
    • 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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
    • H04L1/0045—Arrangements at the receiver end
    • H04L1/0052—Realisations of complexity reduction techniques, e.g. pipelining or use of look-up tables
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03006—Arrangements for removing intersymbol interference
    • H04L25/03178—Arrangements involving sequence estimation techniques
    • H04L25/03203—Trellis search techniques
    • H04L25/03242—Methods involving sphere decoding
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes

Definitions

  • the present application relates to the field of communications, and in particular, to a decoding method, apparatus, and modulation and demodulation method and system based on overlapping multiplexing.
  • the modulation and demodulation technology based on Overlapped X Division Multiplexing includes various implementation schemes, such as modulation and demodulation based on Overlapped Time Division Multiplexing (OvTDM), based on overlapping frequency division multiplexing.
  • OFDM Overlapped Frequency Division Multiplexing
  • OvCDM Overlapped Code Division Multiplexing
  • OFDM Overlapped Space Division Multiplexing
  • OFSDM Overlapped Space Division Multiplexing
  • X represents an arbitrary domain, such as time T, space S, frequency F, code division C, mixed H, and the like.
  • OvTDM optical network management
  • Time Division Multiplexing is a technique for sharing a plurality of signal symbols occupying a narrow time duration in digital communication for a wide time duration.
  • FIG. 1 it is a schematic diagram of a conventional time division multiplexing technique.
  • the time durations of each multiplexed signal symbol in Figure 1 are T1, T2, T3, T4, ..., respectively, which are generally required to occupy the same time slot width in engineering.
  • ⁇ T is the minimum guard slot, and the actual guard slot width should be a bit more.
  • ⁇ T should be greater than the transition time width of the demultiplexed gate used plus the maximum amount of time jitter of the system. This is the most common time division multiplexing technique. Most of the existing multi-channel digital broadcasting systems and multi-channel digital communication systems use this technology.
  • the most important feature of this technology when applied to digital communication is that the multiplexed signal symbols are completely isolated from each other in time, and there is never mutual interference. There is no restriction on the multiplexed signal symbols, and the symbols of the respective signals.
  • the duration (slot width) can have different widths, and can also be applied to different communication systems, as long as their time slots do not overlap each other, and thus are most widely used. But with this multiplexing, multiplexing itself has no effect on improving the spectral efficiency of the system.
  • the conventional view is that adjacent channels do not overlap in the time domain to avoid interference between adjacent channels, but this technique restricts the improvement of spectral efficiency.
  • View of prior art time division multiplexing technology The point is that each channel does not need to be isolated from each other, and can have strong mutual overlap.
  • the prior art regards the overlap between channels as a new coding constraint relationship, and according to the constraint.
  • the relationship proposes a corresponding modulation and demodulation technique, so it is called Overlapped Time Division Multiplexing (OvTDM), which increases the spectral efficiency proportionally to the number of overlaps K.
  • OFTDM Overlapped Time Division Multiplexing
  • the overlapping time division multiplexing system includes a signal transmitter A01 and a receiver A02.
  • Transmitter A01 includes overlapping time division multiplexing modulation device 101 and transmitting device 102.
  • the overlapping time division multiplexing modulation device 101 is configured to generate a complex modulation envelope waveform carrying an input signal sequence; the transmitting device 102 is configured to transmit the complex modulation envelope waveform to the receiver A02.
  • the receiver A02 includes a receiving device 201 and a sequence detecting device 202.
  • the receiving device 201 is configured to receive a complex modulation envelope waveform transmitted by the transmitting device 102.
  • the sequence detecting device 202 is configured to perform time series data sequence detection on the received complex modulation envelope waveform for decision output.
  • receiver A02 also includes pre-processing means 203 disposed between receiving means 201 and sequence detecting means 202 for assisting in the formation of a sequence of synchronous received digital signals within each frame.
  • the input digital signal sequence forms a plurality of transmission signals in which the plurality of symbols overlap each other in the time domain by the overlapping time division multiplexing modulation means 101, and the transmission signal is transmitted from the transmitting means 102 to the receiver A02.
  • the receiving device 201 of the receiver A02 receives the signal transmitted by the transmitting device 102, and forms a digital signal suitable for the sequence detecting device 202 to detect and receive through the pre-processing device 203.
  • the sequence detecting device 202 performs the data sequence detection in the time domain of the received signal, thereby outputting judgment.
  • the overlapping time division multiplexing modulation device 101 includes a waveform generation module 301, a shift module 302, a multiplication module 303, and a superposition module 304.
  • the waveform generation module 301 is configured to generate an initial envelope waveform of the waveform smoothing in the time domain according to the design parameters.
  • the shifting module 302 is configured to shift the initial envelope waveform by a predetermined shift interval in the time domain according to the number of overlapping multiplexing to obtain a shift envelope waveform of each fixed interval.
  • Modulation module 305 is operative to convert the input digital signal sequence into a sequence of signal symbols represented by positive and negative signs.
  • the multiplication module 303 is configured to multiply the sequence of signal symbols by the shifted envelope waveforms of each fixed interval after the offset to obtain respective modulation envelope waveforms.
  • the superposition module 304 is configured to superimpose each modulation envelope waveform in the time domain to obtain a complex modulation envelope waveform carrying the input signal sequence.
  • FIG. 5 is a block diagram of the pre-processing apparatus 203 of the receiver A02.
  • the pre-processing device 203 includes a synchronizer 501, a channel estimator 502, and a digitizer 503.
  • the synchronizer 501 forms symbol time synchronization in the receiver for the received signal; the channel estimator 502 then estimates the channel parameters; the digitizer 503 digitizes the received signal in each frame to form a suitable sequence detecting device. The sequence detects the received digital signal sequence.
  • FIG. 6 is a block diagram of the sequence detecting device 202 of the receiver A02.
  • the sequence detecting means 202 includes an analyzing unit memory 601, a comparator 602 and a plurality of reserved path memories 603 and an Euclidean distance memory 604 or a weighted Euclidean distance memory (not shown).
  • the analysis unit memory 601 makes a complex convolutional coding model and a trellis diagram of the overlapping time division multiplexing system, and lists all states of the overlapping time division multiplexing system, and stores them; and the comparator 602 according to the analysis unit memory 601
  • the trellis diagram in the search for the path of the minimum Euclidean distance or the weighted minimum Euclidean distance of the received digital signal; and the reserved path memory 603 and the Euclidean distance memory 604 or the weighted Euclidean distance memory are used to store the comparator 602, respectively.
  • the reserved path and Euclidean distance or weighted Euclidean distance of the output need to be prepared for each of the stable states.
  • the length of the reserved path memory 603 may preferably be 4K to 5K.
  • the Euclidean distance memory 604 or the weighted Euclidean distance memory preferably stores only relative distances.
  • the signal transmitter modulates the signal and transmits it to the signal receiver, which receives the modulated signal and demodulates it.
  • the demodulation process includes a decoding step (ie, the sequence detection step performed by the sequence detecting device described above).
  • nodes in the folding tree diagram (Trellis diagram) need to be continuously accessed, and two nodes are set for each node.
  • a memory one for storing the Euclidean distance to the relatively optimal path of the node, and one for storing the relatively optimal path to the node.
  • the number of nodes in the Trellis graph is M K .
  • the decoding complexity increases with the overlap weight index. It is well known that in the OvXDM system, the larger the overlap multiplier K, the higher the spectral efficiency, so it is necessary to increase the overlap multiplier K as much as possible, and for the conventional decoding algorithm, such as Viterbi decoding, when the overlap multiplicity is increased to a certain extent When the value is (K>8), the decoding complexity increases sharply.
  • the existing decoding method is difficult to meet the requirements of real-time decoding.
  • the spectral efficiency and the decoding rate form a contradiction. Therefore, it is necessary to reduce the decoding complexity and improve the decoding efficiency.
  • the present application provides a decoding method, apparatus, and modulation and demodulation method and system based on overlapping multiplexing
  • the conventional decoding method for example, when Viterbi decoding is used, although the decoding performance is good, a large amount of storage resources (path storage and distance storage) are required, and the decoding complexity increases exponentially with the number of overlapping multiplexing K.
  • the problem that the decoding rate and the spectral efficiency are contradictory and cannot be put into practical use can improve the decoding rate under the premise of ensuring spectral efficiency.
  • the present application provides a decoding method based on overlapping multiplexing, including:
  • the ball decoding algorithm is used to decode the digital signal in the corresponding domain to obtain an optimal decoding path for decision output.
  • the method includes: setting a search radius in advance, and continuously searching for the intra-ball point. Search for the radius until you find all the paths within the radius of the ball and at least find a complete path to complete the decoding.
  • the present application further provides a decoding apparatus based on overlapping multiplexing, including:
  • An acquisition module configured to acquire a digital signal carrying input information
  • a decoding module configured to decode the digital signal in a corresponding domain based on a ball decoding algorithm to obtain an optimal decoding path for performing a decision output; specifically, the decoding module is configured to preset a search radius, Search for the inner point of the ball, continuously reduce the search radius until all the paths within the radius of the ball are found, and at least one complete path is found to complete the decoding.
  • the present application further provides a modulation and demodulation method based on overlapping multiplexing, including a modulation step and a demodulation step:
  • the modulation steps include:
  • the initial envelope waveform is shifted by a shift interval in the corresponding domain according to the number of overlapping multiplexing to obtain a shifted envelope waveform of each fixed interval;
  • the demodulation steps include:
  • the ball decoding algorithm is used to decode the digital signal in the corresponding domain to obtain an optimal decoding path for decision output.
  • the method includes: setting a search radius in advance, and continuously searching for the intra-ball point. Search for the radius until you find the most likely transmission sequence.
  • the present application further provides a modulation and demodulation system based on overlapping multiplexing, including a transmitter and a receiver;
  • the transmitter includes a modulating device and a transmitting device, and the modulating device includes:
  • a waveform generation module for generating an initial envelope waveform
  • a shifting module configured to shift the initial envelope waveform by a shift interval in the corresponding domain according to the number of overlapping multiplexing to obtain a shift envelope waveform of each fixed interval
  • a modulation module configured to convert the input signal digital sequence into a sequence of signal symbols represented by positive and negative signs
  • a multiplication module configured to multiply a sequence of signal symbols by a shifted envelope waveform of each fixed interval after the offset to obtain a waveform of each modulation envelope
  • a superimposing module configured to superimpose each modulation envelope waveform on a corresponding domain to obtain a complex modulation envelope waveform carrying an input signal sequence
  • the transmitting device is configured to transmit the complex modulation envelope waveform
  • the receiver includes receiving means for receiving the complex modulated envelope waveform and the decoding means described above.
  • the digital signal is decoded in the corresponding domain based on the ball decoding algorithm to obtain an optimal decoding path for decision output.
  • the decoding based on the ball decoding algorithm simplifies the decoding process, saves system resources, reduces the decoding complexity, improves the real-time performance of the decoding output and ensures the performance of the system. Therefore, as the number of overlapping multiplexing increases, the decoding complexity is low. At the same time, under the premise of ensuring better decoding performance, the decoding method with larger overlapping multiplexing times can be put into practical use.
  • 1 is a schematic diagram of a conventional time division multiplexing technique
  • 2 is a schematic diagram of the principle of overlapping time division multiplexing
  • FIG. 3 is a schematic structural diagram of an overlapping time division multiplexing system
  • FIG. 4 is a schematic structural diagram of an overlapping time division multiplexing modulation apparatus
  • FIG. 5 is a schematic structural diagram of a receiver preprocessing apparatus
  • FIG. 6 is a schematic structural diagram of a receiver sequence detecting device
  • FIG. 7 is a schematic flowchart of a decoding method based on overlapping multiplexing according to an embodiment of the present application.
  • Figure 8 is a Trellis diagram of OvTDM
  • FIG. 9 is a schematic diagram of a ball decoding algorithm in an embodiment of the present application.
  • FIG. 10 is a schematic diagram of a process of ball decoding in an embodiment of the present application.
  • FIG. 11 is a schematic structural diagram of a decoding apparatus based on overlapping utilization according to an embodiment of the present application.
  • FIG. 12 is a schematic flowchart of a modulation step in a modulation and demodulation method based on overlapping multiplexing according to an embodiment of the present application
  • Figure 13 is a schematic diagram of the principle of K-way waveform multiplexing
  • FIG. 14 is a schematic diagram showing the principle of a symbol superposition process of a K-way waveform
  • FIG. 15 is a schematic structural diagram of a modulation apparatus in a transmitter according to an embodiment of the present application.
  • X represents an arbitrary domain, such as time T, space S, frequency F, and code division. C, mixed H, etc.
  • OvTDM overlapping time division multiplexing
  • the traditional decoding method it is necessary to continuously access the nodes in the folding tree diagram (Trellis diagram), and for each The node sets up two memories, one for storing the Euclidean distance to the relatively optimal path of the node and one for storing the relatively optimal path to the node.
  • the number of nodes in the Trellis graph is M K . Since the decoding process requires each node to be extended, the number of nodes determines the complexity of decoding, resulting in The decoding complexity increases with the overlap weight index.
  • the inventor adopts a ball decoding algorithm, uses a ball decoding algorithm, and pre-sets a search radius to search for a circle within a sphere, continuously reduces the search radius, and finally finds the most likely transmission sequence.
  • the embodiment provides a decoding method based on overlapping multiplexing, including the following steps:
  • Step 1.1 Obtain a digital signal carrying the input information.
  • the receiving end obtains a digital signal carrying the input information according to the complex modulation envelope waveform.
  • the complex modulation envelope waveform is a waveform carrying the original signal obtained during the modulation process, which is transmitted at the modulation end and received by the demodulation terminal.
  • Step 1.2 Based on the ball decoding algorithm, the digital signal is decoded in the corresponding domain to obtain an optimal decoding path.
  • the method includes: setting a search radius in advance, and performing a cyclic search on the intra-ball point, and continuously reducing the search radius until Find the most likely send sequence.
  • the corresponding domain includes a time domain, an air domain, a frequency domain, a code domain, a hybrid domain, and the like, which are determined by a domain used in the overlap multiplexing technique.
  • Step 1.3 Perform a decision output.
  • ML Maximum Likelihood
  • ZF Zero Forcing
  • MMSE Minimum Mean Square Error
  • SD Sphere Decoder
  • ML is the optimal algorithm but the disadvantage is that the complexity is exponentially increasing and cannot be put into practical use
  • the ZF detection algorithm has the lowest complexity, but the bit error rate is high
  • the MMSE algorithm also has a higher bit error rate
  • the ball decoding algorithm is a kind of A detection algorithm whose performance is close to the ML algorithm but has low complexity. Its basic idea is to accept the vector Y as the center of the sphere, pre-set a search radius C, continuously reduce the search radius by cyclic search of the points inside the ball, and finally find the most likely transmission vector.
  • the ball decoding algorithm is introduced below:
  • ball decoding is to reduce the number of grid points searched, and only search for all grid points in a sphere with the receiving vector as the center of the sphere. If there is a grid point in this search ball, it is easy to know that the nearest grid point must be in the ball, then the nodes outside the ball can be searched without further searching. The number of grid points that need to be searched is greatly reduced, the search points are less, and the natural complexity is It also fell. Ball decoding is an ML algorithm, and finally the optimal maximum likelihood solution can be obtained. The complexity of the ball decoding algorithm is related to the signal-to-noise ratio.
  • the ball decoding theory derivation process is as follows:
  • decompositions include Cholesky decomposition and QR decomposition. Of course, in other embodiments, other decomposition methods that can achieve the same purpose can also be employed.
  • d is the initial set ball decoding radius
  • d' is the sub-radius that gradually decreases as the decoding depth deepens
  • b is the intra-ball point.
  • each parent node has two child nodes (the input information is 1 and -1 respectively), and the i-th level of the code tree map has 2 i nodes, and finally A tree of height n contains a total of 2 n+1 -1 nodes.
  • the node at the 0th level is referred to as a root node
  • the node at the nth level is referred to as a leaf node.
  • the node at each level has two child nodes, except for the root node.
  • Each node has a parent node.
  • the complete path from the root node to a leaf node corresponds to a set of decisions.
  • the ball decoding algorithm is to search for a path with the smallest metric from "tree root" to "leaf" in the "tree” of the code tree diagram.
  • OvXDM ball decoding is to find the position closest to the center of the sphere in the n-dimensional hypersphere with radius d centered on the input information, thus realizing decoding.
  • the radius of the ball is set. Starting from the root node, the node is expanded by the radius of the ball, and then the expanded node continues to expand until the child nodes within the radius of the sphere cannot be found.
  • the sibling node does not have a child node within the radius of the sphere, then it is returned to the parent node, and the sibling node of the parent node is expanded until it is rolled back to the root node, and still cannot find at least one root node to the leaf node.
  • Path recalculate the radius of the ball, increase the radius of the ball by an appropriate amount; repeat this until all paths within the radius of the sphere are found, and at least find a complete path from the root node to the leaf node.
  • One of the plurality of paths finally selected is selected as the final decoded output result, as shown in FIG.
  • the transmission information sequence is x
  • the rectangular wave is a multiplexed waveform
  • the corresponding channel matrix can be represented as H, and its size is (L+K-1) ⁇ L.
  • the transmitting end encodes the information sequence, and after the channel is transmitted, after receiving the signal, the receiving end undergoes a series of signal processing, and finally the sequence to be decoded is y and the length is L.
  • the OvXDM ball decoding process is as follows:
  • the node is extended by the origin and finally returns to the origin.
  • the decoding is performed from the back to the front, and each node is extended, and there are two arriving nodes, if one of the nodes is called If it is a child node, then the corresponding other node is called its sibling node, and the corresponding pre-expansion node is its parent node.
  • the sphere decoding radius is too large, the sphere contains too many points, and the search complexity grows exponentially. If the sphere decoding radius is too small, it may not contain any grid points in the sphere, resulting in an increase in the algorithm. Re-searching after a large radius results in a sharp increase in search complexity. Therefore, it is necessary to set the ball decoding radius reasonably.
  • the range of b k is r is an element in the R matrix R M*M .
  • k M+1 at this time and the ball radius does not contain any nodes, it means that the initial selected sphere radius d is too small, then jump to S2 to reset the sphere radius, and the coefficient ⁇ can be modified to appropriately expand the sphere radius, for example The radius of the sphere is expanded to 1.5 times larger than the original. If the ball radius contains a node indicating that a possible decoding node path can be found at this radius, the decoding process ends.
  • k k-1 is executed, that is, the node continues to be expanded, and the radius of the new child node is calculated.
  • d' 2 k represents the radius of the child node, and as the depth of decoding deepens, the radius of the ball becomes smaller and smaller.
  • the embodiment provides a decoding apparatus based on overlapping multiplexing, including an obtaining module 701 and a decoding module 703.
  • the obtaining module 701 is configured to acquire a digital signal carrying input information.
  • the receiving end obtains a digital signal carrying the input information according to the complex modulation envelope waveform.
  • the complex modulation envelope waveform is a waveform carrying the original signal obtained during the modulation process, which is transmitted at the modulation end and received by the demodulation terminal.
  • the decoding module 703 is configured to decode the digital signal in the corresponding domain based on the ball decoding algorithm to obtain an optimal decoding path for decision output.
  • the corresponding domain includes a time domain, an air domain, a frequency domain, a code domain, a hybrid domain, and the like, which are determined by a domain used in the overlap multiplexing technique.
  • ML Maximum Likelihood
  • ZF Zero Forcing
  • MMSE Minimum Mean Square Error
  • SD Sphere Decoder
  • ML is the optimal algorithm but the disadvantage is that the complexity is exponentially increasing and cannot be put into practical use
  • the ZF detection algorithm has the lowest complexity, but the bit error rate is high
  • the MMSE algorithm also has a higher bit error rate
  • the ball decoding algorithm is a kind of A detection algorithm whose performance is close to the ML algorithm but has low complexity. Its basic idea is to accept the vector Y as the center of the sphere, pre-set a search radius C, continuously reduce the search radius by cyclic search of the points inside the ball, and finally find the most likely transmission vector.
  • the ball decoding algorithm is introduced below:
  • ball decoding is to reduce the number of grid points searched, and only search for all grid points in a sphere with the receiving vector as the center of the sphere. If there is a grid point in this search ball, it is easy to know that the nearest grid point must be in the ball, then the nodes outside the ball can be searched without further searching. The number of grid points that need to be searched is greatly reduced, the search points are less, and the natural complexity is It also fell. Ball decoding is an ML algorithm, and finally the optimal maximum likelihood solution can be obtained. The complexity of the ball decoding algorithm is related to the signal-to-noise ratio.
  • the transmitted end sends a data sequence b ⁇ U M*1 into the channel, and U is a finite character set.
  • the ball decoding theory derivation process is as follows:
  • decompositions include Cholesky decomposition and QR decomposition. Of course, in other embodiments, other decomposition methods that can achieve the same purpose can also be employed.
  • d is the initial set ball decoding radius
  • d' is the sub-half that gradually shrinks as the decoding depth deepens.
  • Path, b is the inside of the ball.
  • each parent node has two child nodes (the input information is 1 and -1 respectively), and the i-th level of the code tree map has 2 i nodes, and finally A tree of height n contains a total of 2 n+1 -1 nodes.
  • the node at the 0th level is referred to as a root node
  • the node at the nth level is referred to as a leaf node.
  • the node at each level has two child nodes, except for the root node.
  • Each node has a parent node.
  • the complete path from the root node to a leaf node corresponds to a set of decisions.
  • the ball decoding algorithm is to search for a path with the smallest metric from "tree root" to "leaf" in the "tree” of the code tree diagram.
  • OvXDM ball decoding is to find the position closest to the center of the sphere in the n-dimensional hypersphere with radius d centered on the input information, thus realizing decoding.
  • the radius of the ball is set. Starting from the root node, the node is expanded by the radius of the ball, and then the expanded node continues to expand until the child nodes within the radius of the sphere cannot be found.
  • the sibling node does not have a child node within the radius of the sphere, then it is returned to the parent node, and the sibling node of the parent node is expanded until it is rolled back to the root node, and still cannot find at least one root node to the leaf node.
  • Path recalculate the radius of the ball, increase the radius of the ball by an appropriate amount; repeat this until all paths within the radius of the sphere are found, and at least find a complete path from the root node to the leaf node.
  • One of the plurality of paths finally selected is selected as the final decoded output result, as shown in FIG.
  • the transmission information sequence is x
  • the rectangular wave is a multiplexed waveform
  • the K-times overlap coding is performed, and the corresponding channel matrix can be represented as H, and its size is (L+K-1) ⁇ L.
  • the transmitting end encodes the information sequence, and after the channel is transmitted, after receiving the signal, the receiving end undergoes a series of signal processing, and finally the sequence to be decoded is y and the length is L.
  • the OvXDM ball decoding process is as follows:
  • the node is extended by the origin and finally returns to the origin.
  • the decoding is performed from the back to the front, and each node is extended, and there are two arriving nodes, if one of the nodes is called If it is a child node, then the corresponding other node is called its sibling node, and the corresponding pre-expansion node is its parent node.
  • the sphere decoding radius is too large, the sphere contains too many points, and the search complexity grows exponentially. If the sphere decoding radius is too small, it may not contain any grid points in the sphere, resulting in an increase in the algorithm. Re-searching after a large radius results in a sharp increase in search complexity. Therefore, it is necessary to set the ball decoding radius reasonably.
  • the range of b k is r is an element in the R matrix R M*M .
  • k M+1 at this time and the ball radius does not contain any nodes, it means that the initial selected sphere radius d is too small, then jump to S2 to reset the sphere radius, and the coefficient ⁇ can be modified to appropriately expand the sphere radius, for example The radius of the sphere is expanded to 1.5 times larger than the original. If the ball radius contains a node indicating that a possible decoding node path can be found at this radius, the decoding process ends.
  • k k-1 is executed, that is, the node continues to be expanded, and the radius of the new child node is calculated.
  • d' 2 k represents the radius of the child node, and as the depth of decoding deepens, the radius of the ball becomes smaller and smaller.
  • the decoding apparatus may further include a pre-processing module 702, configured to perform pre-processing according to the acquired digital signal.
  • the preprocessing includes one or more of synchronization processing, channel estimation equalization processing, digitization processing, and cutting processing.
  • the decoding module 703 is configured to perform decoding according to the preprocessed signal.
  • the pre-processing may be performed in any feasible manner in the prior art, and is not described in this embodiment.
  • This embodiment provides a modulation and demodulation method based on overlapping multiplexing, including a modulation step and a demodulation step.
  • description will be mainly made by modulation and demodulation based on overlapping time division multiplexing.
  • the modulation step includes the following sub-steps:
  • Step 2.1 Generate an initial envelope waveform h(t) in the time domain based on the design parameters.
  • the user can input the design parameters to achieve flexible configuration according to system performance indicators in the actual system.
  • the design parameters include the window length L of the initial envelope waveform, such as when the initial envelope waveform is a Bartlett envelope waveform.
  • the design parameters include the window length L of the initial envelope waveform and the sidelobe attenuation r, such as when the initial envelope waveform is a Chebyshev envelope waveform.
  • the design parameters can be determined according to the characteristics of the corresponding initial envelope waveform.
  • Step 2.2 The initial envelope waveform is shifted according to the predetermined shift interval in the corresponding domain (in the present embodiment, the time domain) according to the number of overlap multiplexing K to obtain the shift envelope waveform h of each fixed interval ( Ti* ⁇ T).
  • the shift interval is a time interval ⁇ T
  • the symbol width of the signal is ⁇ T.
  • Step 2.3 Convert the input signal digital sequence into a sequence of signal symbols represented by positive and negative signs.
  • 0 in the input digital signal sequence is converted to +A
  • 1 is converted to -A
  • A is a non-zero arbitrary number to obtain a sequence of positive and negative symbols.
  • A is 1, the input ⁇ 0, 1 ⁇ bit sequence is converted into a ⁇ +1, -1 ⁇ symbol sequence by BPSK (Binary Phase Shift Keying) modulation.
  • BPSK Binary Phase Shift Keying
  • Step 2.5 superimposing each modulation envelope waveform x i h(ti* ⁇ T) in a corresponding domain (time domain in this embodiment) to obtain a complex modulation envelope waveform carrying the input signal sequence, that is, transmitting signal.
  • the signal sent can be expressed as follows:
  • Step 2.6 The obtained complex modulation envelope waveform is transmitted as a transmission signal.
  • FIG. 13 is a schematic diagram of the principle of K-way waveform multiplexing, which has a parallelogram shape.
  • Each row represents a waveform to be transmitted x i h(ti* ⁇ T) obtained by multiplying a symbol x i to be transmitted with an envelope waveform h (ti* ⁇ T) at a corresponding time.
  • a 0 to a k-1 represent coefficient values of each part obtained by K-segmentation of each window function waveform (envelope waveform), specifically, coefficients regarding amplitude values.
  • FIG. 12 is a schematic diagram showing the principle of the symbol superposition process of the K-way waveform. In the superimposition process of Fig.
  • the third digit on the left side of the first row indicates the first input symbol +1
  • the third digit on the left side of the second row indicates the second input symbol +1
  • the third digit on the left of the third row indicates the third input.
  • Symbol-1 the middle 3 digits of the 1st line represent the 4th input symbol -1
  • the middle 3 digits of the 2nd row represent the 5th input symbol -1
  • the 3rd row of the 3rd row represents the 6th input symbol + 1.
  • the third number on the right side of the first line indicates the seventh input symbol -1
  • the third number on the right side of the second line indicates the eighth input symbol +1. Therefore, after the three waveforms are superimposed, the resulting output symbol is ⁇ +1+2+1-1-3-1-1+1 ⁇ .
  • the demodulating step includes: receiving a complex modulation envelope waveform; acquiring a digital signal carrying the input information according to the complex modulation envelope waveform; and decoding the digital signal in the corresponding domain based on the ball decoding algorithm to obtain the best Decode the path for decision output.
  • the decoding method in the demodulation step uses the decoding method provided in the first embodiment, and details are not described herein.
  • the embodiment based on the multiplexing and multiplexing based modulation and demodulation method provided in the foregoing embodiment 3, the embodiment provides a modulation and demodulation system based on overlapping multiplexing, including a transmitter and a receiver.
  • the transmitter includes a modulation device and a transmitting device.
  • the modulation device includes a waveform generation module 801, a shift module 802, a modulation module 803, a multiplication module 804, and a superposition module 805.
  • the waveform generation module 801 is configured to generate an initial envelope waveform. In the present embodiment, description will be mainly made by modulation and demodulation based on overlapping time division multiplexing. It generates an initial envelope waveform h(t) in the time domain based on the design parameters.
  • the user can input the design parameters to achieve flexible configuration according to system performance indicators in the actual system.
  • the design parameters include the window length L of the initial envelope waveform, such as when the initial envelope waveform is a Bartlett envelope waveform.
  • the design parameters include the window length L of the initial envelope waveform and the sidelobe attenuation r, such as when the initial envelope waveform is a Chebyshev envelope waveform.
  • the design parameters can be determined according to the characteristics of the corresponding initial envelope waveform.
  • the shifting module 802 is configured to shift the initial envelope waveform in a corresponding domain (in the present embodiment, the time domain) according to the number of overlapping multiplexings to obtain a shift envelope waveform h of each fixed interval. Ti* ⁇ T).
  • the shift interval is a time interval ⁇ T
  • the symbol width of the signal is ⁇ T.
  • the modulation module 803 is configured to convert the input signal digital sequence into a sequence of signal symbols represented by positive and negative signs.
  • 0 in the input digital signal sequence is converted to +A
  • 1 is converted to -A
  • A is a non-zero arbitrary number to obtain a sequence of positive and negative symbols.
  • A is 1, the input ⁇ 0, 1 ⁇ bit sequence is converted into a ⁇ +1, -1 ⁇ symbol sequence by BPSK (Binary Phase Shift Keying) modulation.
  • BPSK Binary Phase Shift Keying
  • the multiplication module 804 is configured to multiply the signal symbol sequence x i by the fixed-interval shifted envelope waveform h(ti* ⁇ T) to obtain each modulation envelope waveform x i h(ti* ⁇ T).
  • the superimposing module 805 is configured to superimpose each modulation envelope waveform x i h(ti* ⁇ T) in a corresponding domain (in the present embodiment, a time domain) to obtain a complex modulation envelope waveform carrying the input signal sequence, that is, The signal sent.
  • the signal sent can be expressed as follows:
  • the transmitting device is configured to transmit the complex modulation envelope waveform as a transmission signal.
  • the receiver includes receiving means for receiving the complex modulated envelope waveform and any of the overlapping multiplexing based decoding means provided in the second embodiment, which is not described in this embodiment.
  • the digital signal is decoded in the corresponding domain based on the ball decoding algorithm to obtain an optimal decoding path for decision output.
  • the decoding based on the ball decoding algorithm simplifies the decoding process, saves system resources, reduces the decoding complexity, improves the real-time performance of the decoding output and ensures the performance of the system. Therefore, as the number of overlapping multiplexing increases, the decoding complexity is low. At the same time, under the premise of ensuring better decoding performance, the decoding method with larger overlapping multiplexing times can be put into practical use.
  • the demodulation method and system can be applied to wireless communication systems such as mobile communication, satellite communication, microwave line-of-sight communication, scatter communication, atmospheric optical communication, infrared communication, underwater acoustic communication, etc., and can be applied to large-capacity wireless transmission or Used in small-capacity light radio systems.
  • the program may be stored in a computer readable storage medium, and the storage medium may include: a read only memory. Random access memory, disk or optical disk, etc.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Error Detection And Correction (AREA)

Abstract

一种基于重叠复用的译码方法、装置及调制解调方法和系统，基于球译码算法对携带有输入信息的数字信号在相应域内进行译码，得到最佳译码路径，以进行判决输出。基于球译码算法进行译码，简化了译码过程，节省了系统资源，降低了译码复杂度，同时提高译码输出的实时性并保证了系统的性能。从而实现了随着重叠复用次数的增加，译码复杂度较低。同时又能在保证较好的译码性能的前提下，使得重叠复用次数较大的译码方法能够实用化。

Description

基于重叠复用的译码方法、装置及调制解调方法和系统 技术领域
本申请涉及通信领域，具体涉及一种基于重叠复用的译码方法、装置及调制解调方法和系统。
背景技术
基于重叠复用(OvXDM：Overlapped X Division Multiplexing)的调制解调技术包括多种具体实现方案，比如基于重叠时分复用(OvTDM：Overlapped Time Division Multiplexing)的调制解调技术、基于重叠频分复用(OvFDM：Overlapped Frequency Division Multiplexing)的调制解调技术、基于重叠码分复用(OvCDM：Overlapped Code Division Multiplexing)的调制解调技术、基于重叠空分复用(OvSDM：Overlapped Space Division Multiplexing)的调制解调技术、基于重叠混合复用(OvHDM：Overlapped Hybrid Division Multiplexing)的调制解调技术等。
需要说明的是，本申请中提及的OvXDM中，X代表任意域，例如时间T、空间S、频率F、码分C、混合H等。
下面仅以OvTDM为例进行简单说明。
首先，所谓时间分割(以下简称时分)复用(TDM：Time Division Multiplexing)是一种在数字通信中让多个占据较窄时间持续期的信号符号共享一个较宽时间持续期的技术。如图1所示，为常规的时分复用技术的示意图。
图1中各被复用信号符号的时间持续期(工程上称之为时隙宽度)分别为T1，T2，T3，T4，...，在工程上通常让它们占据相同的时隙宽度，ΔT为最小保护时隙，实际保护时隙宽度应该宽裕一些。ΔT应大于所使用解复用门电路的过渡时间宽度加上系统的最大时间抖动量。这是最常见的时分复用技术。现有绝大多数的多路数字广播系统、多路数字通信等系统采用的都是这种技术。
这种技术应用于数字通信时的最大特点是被复用信号符号之间在时间上是完全相互隔离的，决不会存在相互干扰，对被复用的信号符号没有任何限制，各个信号的符号持续期(时隙宽度)可以有不同的宽度，也能适用于不同的通信体制，只要它们的时隙相互不重叠交叉就可以了，因此使用最为广泛。但是这种复用，复用本身对改善系统的频谱效率毫无作用。
所以，传统的观点是相邻信道之间在时域上不重叠，以避免相邻信道之间产生干扰，但这种技术制约了频谱效率的提高。现有技术的时分复用技术的观 点是各信道之间不但不需要相互隔离，而且可以有很强的相互重叠，如图2所示，现有技术将信道之间的重叠视为一种新的编码约束关系，并根据该约束关系提出了相应的调制和解调技术，因此称之为重叠时分复用(OvTDM：Overlapped Time Division Multiplexing)，这种技术使得频谱效率随重叠次数K成比例的增加。
请参考图3，重叠时分复用系统包括信号发射机A01和接收机A02。
发射机A01包括重叠时分复用调制装置101和发射装置102。重叠时分复用调制装置101用于生成携带输入信号序列的复调制包络波形；发射装置102用于将该复调制包络波形发射到接收机A02。
接收机A02包括接收装置201和序列检测装置202。接收装置201用于接收发射装置102发射的复调制包络波形；序列检测装置202用于对接收的复调制包络波形进行时域内的数据序列检测，以进行判决输出。
通常，接收机A02还包括设置在接收装置201和序列检测装置202之间的预处理装置203，用于辅助形成每一帧内的同步接收数字信号序列。
在发射机A01中，输入的数字信号序列通过重叠时分复用调制装置101形成多个符号在时域上相互重叠的发射信号，再由发射装置102将该发射信号发射到接收机A02。接收机A02的接收装置201接收发射装置102发射的信号，经过预处理装置203形成适合序列检测装置202进行检测接收的数字信号，序列检测装置202对接收信号进行时域内的数据序列检测，从而输出判决。
请参考图4，重叠时分复用调制装置101(OvTDM调制装置)包括波形生成模块301、移位模块302、乘法模块303和叠加模块304。
波形生成模块301用于根据设计参数生成在时域内波形平滑的初始包络波形。
移位模块302用于根据重叠复用次数将初始包络波形在时域内按预定的移位间隔进行移位，以得到各固定间隔的移位包络波形。
调制模块305用于将输入的数字信号序列转换成正负符号表示的信号符号序列。
乘法模块303用于将所述信号符号序列与偏移后各固定间隔的移位包络波形相乘，以得到各调制包络波形。
叠加模块304用于将各调制包络波形在时域上进行叠加，以得到携带输入信号序列的复调制包络波形。
请参考图5，为接收机A02的预处理装置203的框图。
预处理装置203包括同步器501、信道估计器502和数字化处理器503。其中同步器501对接收信号在接收机内形成符号时间同步；接着信道估计器502对信道参数进行估计；数字化处理器503对每一帧内的接收信号进行数字化处理，从而形成适合序列检测装置进行序列检测接收的数字信号序列。
请参考图6，为接收机A02的序列检测装置202的框图。
序列检测装置202包括分析单元存储器601、比较器602及多个保留路径存储器603和欧氏距离存储器604或加权欧氏距离存储器(图中未示出)。在检测过程中，分析单元存储器601做出重叠时分复用系统的复数卷积编码模型及格状图，并列出重叠时分复用系统的全部状态，并存储；而比较器602根据分析单元存储器601中的格状图，搜索出与接收数字信号最小欧氏距离或加权最小欧氏距离的路径；而保留路径存储器603和欧氏距离存储器604或加权欧氏距离存储器则分别用于存储比较器602输出的保留路径和欧氏距离或加权欧氏距离。其中，保留路径存储器603和欧氏距离存储器604或加权欧氏距离存储器需要为每一个稳定状态各准备一个。保留路径存储器603长度可以优选为4K～5K。欧氏距离存储器604或加权欧氏距离存储器优选为只存储相对距离。
在OvXDM系统中，信号发射机对信号调制后发射给信号接收机，信号接收机接收到调制信号后对其进行解调。解调过程中包括译码步骤(即上述序列检测装置执行的序列检测步骤)，在传统译码中，需要不断的访问折叠树图(Trellis图)中的节点，并为每一个节点设置两个存储器，一个用于存储达到该节点的相对最佳路径的欧氏距离，一个用于存储到达该节点的相对最佳路径。对于一个重叠重数为K的M维调制的系统，Trellis图中的节点数为MK，由于译码过程中，需要对每个节点进行扩展，因此节点数决定了译码的复杂度，造成译码复杂度随重叠重数指数增加。众所周知，OvXDM系统中，重叠重数K越大频谱效率越高，因此需要尽可能的增加重叠重数K，而对于传统的译码算法，如维特比译码，当重叠重数增大到一定值(K>8)时，译码复杂度急剧增加，现有译码方法难以满足实时译码的需求，频谱效率与译码速率就形成了一对矛盾。因此，需要降低译码复杂度，提升译码效率。
发明内容
本申请提供一种基于重叠复用的译码方法、装置及调制解调方法和系统， 解决了传统译码方法中，例如采用维特比译码时，虽然译码性能较好，但是需要大量的存储资源(路径存储和距离存储)，译码复杂度随重叠复用次数K呈指数增加，提高译码速率和频谱效率相矛盾，无法实用化的问题，能够在保证频谱效率的前提下，提高译码速率。
根据本申请的第一方面，本申请提供了一种基于重叠复用的译码方法，包括：
获取携带有输入信息的数字信号；
基于球译码算法对所述数字信号在相应域内进行译码，得到最佳译码路径，以进行判决输出；具体包括：预先设定一个搜索半径，对球内格点循环搜索，不断减小搜索半径，直至找完球半径内的所有路径，并至少找到了一条完整路径，完成译码。
根据本申请的第二方面，本申请还提供了一种基于重叠复用的译码装置，包括：
获取模块，用于获取携带有输入信息的数字信号；
译码模块，用于基于球译码算法对所述数字信号在相应域内进行译码，得到最佳译码路径，以进行判决输出；具体为：译码模块用于预先设定一个搜索半径，对球内格点循环搜索，不断减小搜索半径，直至找完球半径内的所有路径，并至少找到了一条完整路径，完成译码。
根据本申请的第三方面，本申请还提供了一种基于重叠复用的调制解调方法，包括调制步骤和解调步骤：
调制步骤包括：
生成初始包络波形；
根据重叠复用次数将初始包络波形在相应域内按移位间隔进行移位，以得到各固定间隔的移位包络波形；
将输入的信号数字序列转换成正负符号表示的信号符号序列；
将信号符号序列与偏移后各固定间隔的移位包络波形相乘，以得到各调制包络波形；
将各调制包络波形在相应域上进行叠加，以得到携带所述信号数字序列的复调制包络波形；
将所述复调制包络波形发射出去；
解调步骤包括：
接收所述复调制包络波形；
根据所述复调制包络波形获取携带有输入信息的数字信号；
基于球译码算法对所述数字信号在相应域内进行译码，得到最佳译码路径，以进行判决输出；具体包括：预先设定一个搜索半径，对球内格点循环搜索，不断减小搜索半径，直至找到最具可能性的发送序列。
根据本申请的第四方面，本申请还提供了一种基于重叠复用的调制解调系统，包括发射机和接收机；
所述发射机包括调制装置和发射装置，所述调制装置包括：
波形生成模块，用于生成初始包络波形；
移位模块，用于根据重叠复用次数将初始包络波形在相应域内按移位间隔进行移位，以得到各固定间隔的移位包络波形；
调制模块，用于将输入的信号数字序列转换成正负符号表示的信号符号序列；
乘法模块，用于将信号符号序列与偏移后各固定间隔的移位包络波形相乘，以得到各调制包络波形；
叠加模块，用于将各调制包络波形在相应域上进行叠加，以得到携带输入信号序列的复调制包络波形；
所述发射装置用于将所述复调制包络波形发射出去；
所述接收机包括用于接收所述复调制包络波形的接收装置和上述的译码装置。
本申请提供的基于重叠复用的译码方法、装置及调制解调方法和系统中，基于球译码算法对数字信号在相应域内进行译码，得到最佳译码路径，以进行判决输出。基于球译码算法进行译码，简化了译码过程，节省了系统资源，降低了译码复杂度，同时提高译码输出的实时性并保证了系统的性能。从而实现了随着重叠复用次数的增加，译码复杂度较低。同时又能在保证较好的译码性能的前提下，使得重叠复用次数较大的译码方法能够实用化。
附图说明
图1为常规的时分复用技术的示意图；
图2为重叠时分复用原理示意图；
图3为一种重叠时分复用系统的结构示意图；
图4为一种重叠时分复用调制装置的结构示意图；
图5为一种接收机预处理装置的结构示意图；
图6为一种接收机序列检测装置的结构示意图；
图7为本申请一种实施例中基于重叠复用的译码方法的流程示意图；
图8为OvTDM的Trellis图；
图9为本申请一种实施例中球译码算法的示意图；
图10为本申请一种实施例中球译码的过程示意图；
图11为本申请一种实施例中基于重叠利用的译码装置的结构示意图；
图12为本申请一种实施例中基于重叠复用的调制解调方法中调制步骤的流程示意图；
图13为K路波形复用的原理示意图；
图14为K路波形的符号叠加过程原理示意图；
图15为本申请一种实施例发射机中调制装置的结构示意图。
具体实施方式
首先，需要说明的是，本申请提供的基于重叠复用(OvXDM)的译码方法、装置及调制解调方法和系统中，X代表任意域，例如时间T、空间S、频率F、码分C、混合H等。为了便于说明，本申请实施例主要以重叠时分复用(OvTDM)为例进行说明。本领域技术人员人应当知晓，本申请要求保护的基于重叠复用的译码方法、装置及调制解调方法和系统同样可以应用于其他域的重叠复用技术中。
在对重叠复用调制解调技术研究中，本领域技术人员皆采用传统的译码方法，在传统译码方法中，需要不断的访问折叠树图(Trellis图)中的节点，并为每一个节点设置两个存储器，一个用于存储达到该节点的相对最佳路径的欧氏距离，一个用于存储到达该节点的相对最佳路径。对于一个重叠重数为K的M维调制的系统，Trellis图中的节点数为MK，由于译码过程中，需要对每个节点进行扩展，因此节点数决定了译码的复杂度，造成译码复杂度随重叠重数指数增加。众所周知，OvXDM系统中，重叠重数K越大频谱效率越高，因此需要尽可能的增加重叠重数K，而对于传统的译码算法，如维特比译码，当重叠重数增大到一定值(K>8)时，译码复杂度急剧增加，现有译码方法难以满足实时译码的需求，频谱效率与译码速率就形成了一对矛盾。
然而，虽然目前的译码方法中存在上述问题，但是由于这些方法已广为使 用，本领域技术人员已全面接受使用这种方法，而不再花费成本去寻找更优的译码方法。
本申请中，发明人通过采用不同的技术构思，采用球译码算法，通过预先设定一个搜索半径，对球内格点循环搜索，不断减小搜索半径，最终找到最具可能性的发送序列，从而解决上述技术问题。
下面通过具体实施方式结合附图对本申请作进一步详细说明。
实施例一
请参考图7，本实施例提供了一种基于重叠复用的译码方法，包括下面步骤：
步骤1.1：获取携带有输入信息的数字信号。接收端根据复调制包络波形得到携带有输入信息的数字信号。复调制包络波形为调制过程中得到的携带有原始信号的波形，其在调制端被发射出来，由解调端接收。
步骤1.2：基于球译码算法对数字信号在相应域内进行译码，得到最佳译码路径；具体包括：预先设定一个搜索半径，对球内格点循环搜索，不断减小搜索半径，直至找到最具可能性的发送序列。其中，相应域包括时域、空域、频域、码域、混合域等，其由重叠复用技术中采用的域确定。
步骤1.3：进行判决输出。
在重叠复用调制解调技术中，常用的检测算法有：最大似然算法(ML，Maximum Likelihood)、迫零检测算法(ZF，Zero Forcing)、最小均方误差算法(MMSE，Minimum Mean Square Error)、球型译码算法(SD，Sphere Decoder)等。ML为最优算法但缺点是复杂度呈指数增长无法实用化；ZF检测算法具有最低的复杂度，但是误码率较高；MMSE算法也有较高的误码率；球译码算法是一种性能接近于ML算法但复杂度低的检测算法。它的基本思想是以接受矢量Y为球心，预先设定一个搜索半径C，通过对球内点的循环搜索不断减小搜索半径，最终找到最具可能性的发送向量。
下面对球译码算法进行介绍：
球译码的思想是减少搜索的格点数，仅搜索在以接收矢量为球心的一个球体内的所有格点。如果在这个搜索球内存在格点，易知最近格点必然在该球内，那么球外的节点都可以不用再搜索，需要搜索的格点数大大减少了，搜索的点少了，自然复杂度也就下降了。球译码是一种ML算法，最终可以得到最优的最大似然解，球译码算法复杂度与信噪比有关系。
假设发送端发送数据序列b∈UM*1进入信道，U为一有限字符集。接收到的 信号y可表示为y＝Hb，其中y∈UM*1是接收向量，H∈UN*M是信道矩阵，矩阵的列数为M行数为N；H在接收端是已知的，球译码的目的就是在接收端找到一组码序列
Figure PCTCN2017091964-appb-000001
使其满足
Figure PCTCN2017091964-appb-000002
且满足||y-Hb||2≤d2，d为球译码半径。
球译码理论推导过程如下：
(1)对信道矩阵H进行分解
常用的分解包括Cholesky(乔里斯基)分解和QR分解。当然，在其他实施例中，也可以采用其他可以达到同样目的分解方法。
Cholesky分解是将H分解为H＝LTL，其中L是M位的非奇异上三角矩阵；QR分解是将H分解为H＝QR，Q是酉矩阵，R是上三角矩阵。
本实施例中，采用QR分解法，将H分解为H＝QR，如果H的大小表示为N×M(N≥M)，那么经过QR分解后，R是M×M上三角矩阵，Q＝[Q1 Q2]是N×N的正交矩阵，矩阵Q1和Q2分别代表Q的前M列和后N-M列，因此H也可以写成：
Figure PCTCN2017091964-appb-000003
(2)寻找球体内格点
将(1)中经过QR分解的H矩阵带入关系式||y-Hb||2≤d2中得到
Figure PCTCN2017091964-appb-000004
令
Figure PCTCN2017091964-appb-000005
则推导出
Figure PCTCN2017091964-appb-000006
由
Figure PCTCN2017091964-appb-000007
推导出，
Figure PCTCN2017091964-appb-000008
推广到K时，
Figure PCTCN2017091964-appb-000009
Figure PCTCN2017091964-appb-000010
其中d为初始设定的球译码半径，d'为随着译码深度的加深逐渐缩小的子半径，b为球内格点。经过反复的寻找球内格点，确定最终的译码路径。
由OvXDM的码树图(如图8所示)可知，每一个父节点有两个子节点(分别对应输入信息为1和-1)，码树图的第i级一共有2i个节点，最终高度为n的树中总共含有2n+1-1个节点。在图8中，第0级的节点被称为根节点，第n级的节点被称为叶子节点，除第n级的叶子节点外，每一级的节点都有两个子节点，除根节点外，每个节点都有一个父节点。从根节点到某个叶子节点的完整路径，都对应着一组判决结果。球译码算法也就是在码树图这个“树”中，搜索一条度量最小的从“树根”到“叶子”的路径。
OvXDM球译码的思想就是以输入信息为中心，在半径为d的n维超球内寻找最接近球心的位置，从而实现译码。首先根据信噪比设定球半径，从根节点出发，通过球半径对节点进行扩展，然后对扩展后的节点继续扩展，直至无法找到球半径内的子节点，此时对其相应的兄节点进行扩展，如果兄节点也没有在球半径内的子节点，则退回至父节点，对父节点的兄弟节点进行扩展，直到回退到根节点，仍然无法找到至少一条根节点到叶子节点的完整路径，重新计算球半径，将球半径适量的增大；如此反复进行，直至找完球半径内的所有路径，并至少找到了一条根节点到叶子节点的完整路径，此时结束译码，从最终筛选出的多条路径中选出距离最小的一条路径作为最终的译码输出结果，如附图9所示。
本实施中假设发送信息序列为x，信息长度L＝10，重叠次数K＝5，以矩形波为复用波形，其复用波形系数表示为h＝[1,1,1,1,1]，对其进行K次重叠编码， 对应的信道矩阵可表示为H，其大小为(L+K-1)×L。发送端对信息序列进行编码，经过信道传输，接收端收到信号后，经过一系列信号处理，最终得到待译码的序列为y，长度为L。
如图10所示，OvXDM的球译码过程如下：
S1：对信道矩阵H进行QR分解
对信道矩阵H进行QR分解，表示为H＝QR，如果H的大小表示为N×M(N≥M)，那么经过QR分解后，R是M×M上三角矩阵，Q＝[Q1 Q2]是N×N的正交矩阵，矩阵Q1和Q2分别代表Q的前M列和后N-M列，因此H也可以写成
Figure PCTCN2017091964-appb-000011
本实施例中N＝L+K-1＝14，M＝L＝10。
S2：设定初始球译码半径d，令k＝M。
根据公式d2＝αNδ2设定球半径大小，球半径的大小与数据长度N和噪声方差δ2有关，α为半径系数，可根据实际情况对球半径大小适当调整，是经验值。
由OvXDM的Trellis图可知，节点由原点扩展最后还会回归到原点，本实施例中，采用从后向前的顺序译码，每一个节点经过扩展，有两个到达节点，如果称其中一个节点为子节点的话，那么对应的另一个节点称为其兄节点，对应的扩展前的节点为其父节点。
需要说明的是，球译码半径太大，球体内包含的点太多，搜索复杂度成指数形式增长；球译码半径太小，就可能在球体内不包含任何格点，导致算法在增大半径之后进行重新搜索，导致搜索复杂度急剧上升。所以，需要合理地设置球译码半径。
S3：计算zk|k+1和dk'2，确定bk的范围
由上述球译码理论推导过程可知，
Figure PCTCN2017091964-appb-000012
Figure PCTCN2017091964-appb-000013
k为节点索引，由于从后向前译码，k＝1时，表示最后一个译码节点。k＝M时，zM＝Q1 *y，其中Q1是S1中QR分解得到的，y是待译码序列；d'2 k＝d2，d为S2中设置的初始球半径，当k≠M时，随着译码深度的加深，球半径逐渐缩小，将d'称为子半径。
bk的范围为
Figure PCTCN2017091964-appb-000014
r为R矩阵RM*M中的元素。
S4：选取一个bk，如果为空，跳至S5；否则，跳至S6。
在球半径内选取一个节点bk，对其进行扩展，如果扩展后的节点不在球半径内，那么退回到该节点的父节点，进行步骤S5；如果扩展后的节点在该球半径内，那么继续对该节点进行扩展，进行步骤S6。
S5：k＝k+1返回父节点，如果k＝M+1，且{bk}为空，跳至S2；如果{bk}不为空，结束；否则跳至S4。
如果此时k＝M+1且球半径内不包含任何节点，说明初始选择的球半径d过小，那么跳至S2重新设定球半径，可修改系数α适当的将球半径扩大，比如将球半径扩展为原先的1.5倍大。如果球半径内包含节点，说明此半径下可找到可能的译码节点路径，则译码过程结束。
如果此时k≠M+1，说明回退节点还没有到达最后一个符号，则可以继续对该节点的兄节点进行扩展判定，跳至S4。
S6：如果k＝1，跳至S7，否则k＝k-1，计算子节点的半径。
如果此时k＝1，说明在此初始球半径d范围内，已经找到一条完整的M个节点的路径，则跳至S7。
如果k≠1，执行k＝k-1，即继续对此节点进行扩展，计算新的子节点的半径。
Figure PCTCN2017091964-appb-000015
其中d'2 k表示子节点半径，随着译码深度的加深，球半径越来越小。
S7：保存该球半径中的全部节点{bk}，跳至S4。
S8：译码输出。如此反复进行，当球半径内的所有节点都到达数据序列的最后一个符号，从筛选出的多条路径中找出距离最小的一组作为译码的最终输出结果。
实施例二
请参考图11，本实施例提供了一种基于重叠复用的译码装置，包括获取模块701和译码模块703。
获取模块701用于获取携带有输入信息的数字信号。接收端根据复调制包络波形得到携带有输入信息的数字信号。复调制包络波形为调制过程中得到的携带有原始信号的波形，其在调制端被发射出来，由解调端接收。
译码模块703用于基于球译码算法对数字信号在相应域内进行译码，得到最佳译码路径，以进行判决输出。其中，相应域包括时域、空域、频域、码域、混合域等，其由重叠复用技术中采用的域确定。
在重叠复用调制解调技术中，常用的检测算法有：最大似然算法(ML，Maximum Likelihood)、迫零检测算法(ZF，Zero Forcing)、最小均方误差算法(MMSE，Minimum Mean Square Error)、球型译码算法(SD，Sphere Decoder)等。ML为最优算法但缺点是复杂度呈指数增长无法实用化；ZF检测算法具有最低的复杂度，但是误码率较高；MMSE算法也有较高的误码率；球译码算法是一种性能接近于ML算法但复杂度低的检测算法。它的基本思想是以接受矢量Y为球心，预先设定一个搜索半径C，通过对球内点的循环搜索不断减小搜索半径，最终找到最具可能性的发送向量。
下面对球译码算法进行介绍：
球译码的思想是减少搜索的格点数，仅搜索在以接收矢量为球心的一个球体内的所有格点。如果在这个搜索球内存在格点，易知最近格点必然在该球内，那么球外的节点都可以不用再搜索，需要搜索的格点数大大减少了，搜索的点少了，自然复杂度也就下降了。球译码是一种ML算法，最终可以得到最优的最大似然解，球译码算法复杂度与信噪比有关系。
假设发送端发送数据序列b∈UM*1进入信道，U为一有限字符集。接收到的信号y可表示为y＝Hb，其中y∈UM*1是接收向量，H∈UN*M是信道矩阵，H在接收端是已知的，球译码的目的就是在接收端找到一组码序列
Figure PCTCN2017091964-appb-000016
使其满足
Figure PCTCN2017091964-appb-000017
且满足||y-Hb||2≤d2，d为球译码半径。
球译码理论推导过程如下：
(1)对信道矩阵H进行分解
常用的分解包括Cholesky(乔里斯基)分解和QR分解。当然，在其他实施例中，也可以采用其他可以达到同样目的分解方法。
Cholesky分解是将H分解为H＝LTL，其中L是M位的非奇异上三角矩阵；QR分解是将H分解为H＝QR，Q是酉矩阵，R是上三角矩阵。
本实施例中，采用QR分解法，将H分解为H＝QR，如果H的大小表示为N×M(N≥M)，那么经过QR分解后，R是M×M上三角矩阵，Q＝[Q1 Q2]是N×N 的正交矩阵，矩阵Q1和Q2分别代表Q的前M列和后N-M列，因此H也可以写成：
Figure PCTCN2017091964-appb-000018
(2)寻找球体内格点
将(1)中经过QR分解的H矩阵带入关系式||y-Hb||2≤d2中得到
Figure PCTCN2017091964-appb-000019
令
Figure PCTCN2017091964-appb-000020
则推导出
Figure PCTCN2017091964-appb-000021
由
Figure PCTCN2017091964-appb-000022
推导出，
Figure PCTCN2017091964-appb-000023
推广到K时，
Figure PCTCN2017091964-appb-000024
Figure PCTCN2017091964-appb-000025
其中d为初始设定的球译码半径，d'为随着译码深度的加深逐渐缩小的子半 径，b为球内格点。k为节点索引，由于从后向前译码，k＝1时，表示最后一个译码节点。经过反复的寻找球内格点，确定最终的译码路径。
由OvXDM的码树图(如图8所示)可知，每一个父节点有两个子节点(分别对应输入信息为1和-1)，码树图的第i级一共有2i个节点，最终高度为n的树中总共含有2n+1-1个节点。在图8中，第0级的节点被称为根节点，第n级的节点被称为叶子节点，除第n级的叶子节点外，每一级的节点都有两个子节点，除根节点外，每个节点都有一个父节点。从根节点到某个叶子节点的完整路径，都对应着一组判决结果。球译码算法也就是在码树图这个“树”中，搜索一条度量最小的从“树根”到“叶子”的路径。
OvXDM球译码的思想就是以输入信息为中心，在半径为d的n维超球内寻找最接近球心的位置，从而实现译码。首先根据信噪比设定球半径，从根节点出发，通过球半径对节点进行扩展，然后对扩展后的节点继续扩展，直至无法找到球半径内的子节点，此时对其相应的兄节点进行扩展，如果兄节点也没有在球半径内的子节点，则退回至父节点，对父节点的兄弟节点进行扩展，直到回退到根节点，仍然无法找到至少一条根节点到叶子节点的完整路径，重新计算球半径，将球半径适量的增大；如此反复进行，直至找完球半径内的所有路径，并至少找到了一条根节点到叶子节点的完整路径，此时结束译码，从最终筛选出的多条路径中选出距离最小的一条路径作为最终的译码输出结果，如附图9所示。
本实施中假设发送信息序列为x，信息长度L＝10，重叠次数K＝5，以矩形波为复用波形，其复用波形系数表示为h＝[1,1,1,1,1]，对其进行K次重叠编码，对应的信道矩阵可表示为H，其大小为(L+K-1)×L。发送端对信息序列进行编码，经过信道传输，接收端收到信号后，经过一系列信号处理，最终得到待译码的序列为y，长度为L。
如图10所示，OvXDM的球译码过程如下：
S1：对信道矩阵H进行QR分解
对信道矩阵H进行QR分解，表示为H＝QR，如果H的大小表示为N×M(N≥M)，那么经过QR分解后，R是M×M上三角矩阵，Q＝[Q1 Q2]是N×N的正交矩阵，矩阵Q1和Q2分别代表Q的前M列和后N-M列，因此H也可以写成
Figure PCTCN2017091964-appb-000026
本实施例中N＝L+K-1＝14，M＝L＝10。
S2：设定初始球译码半径d，令k＝M。
根据公式d2＝αNδ2设定球半径大小，球半径的大小与数据长度N和噪声方差δ2有关，α为半径系数，可根据实际情况对球半径大小适当调整，是经验值。
由OvXDM的Trellis图可知，节点由原点扩展最后还会回归到原点，本实施例中，采用从后向前的顺序译码，每一个节点经过扩展，有两个到达节点，如果称其中一个节点为子节点的话，那么对应的另一个节点称为其兄节点，对应的扩展前的节点为其父节点。
需要说明的是，球译码半径太大，球体内包含的点太多，搜索复杂度成指数形式增长；球译码半径太小，就可能在球体内不包含任何格点，导致算法在增大半径之后进行重新搜索，导致搜索复杂度急剧上升。所以，需要合理地设置球译码半径。
S3：计算zk|k+1和dk'2，确定bk的范围
由上述球译码理论推导过程可知，
Figure PCTCN2017091964-appb-000027
Figure PCTCN2017091964-appb-000028
k＝M时，zM＝Q1 *y，其中Q1是S1中QR分解得到的，y是待译码序列；d'2 k＝d2，d为S2中设置的初始球半径，当K≠M时，随着译码深度的加深，球半径逐渐缩小，将d'称为子半径。
bk的范围为
Figure PCTCN2017091964-appb-000029
r为R矩阵RM*M中的元素。
S4：选取一个bk，如果为空，跳至S5；否则，跳至S6。
在球半径内选取一个节点bk，对其进行扩展，如果扩展后的节点不在球半径内，那么退回到该节点的父节点，进行步骤S5；如果扩展后的节点在该球半径内，那么继续对该节点进行扩展，进行步骤S6。
S5：k＝k+1返回父节点，如果k＝M+1，且{bk}为空，跳至S2；如果{bk}不为空，结束；否则跳至S4。
如果此时k＝M+1且球半径内不包含任何节点，说明初始选择的球半径d过小，那么跳至S2重新设定球半径，可修改系数α适当的将球半径扩大，比如将球半径扩展为原先的1.5倍大。如果球半径内包含节点，说明此半径下可找到可能的译码节点路径，则译码过程结束。
如果此时k≠M+1，说明回退节点还没有到达最后一个符号，则可以继续对该节点的兄节点进行扩展判定，跳至S4。
S6：如果k＝1，跳至S7，否则k＝k-1，计算子节点的半径。
如果此时k＝1，说明在此初始球半径d范围内，已经找到一条完整的M个节点的路径，则跳至S7。
如果k≠1，执行k＝k-1，即继续对此节点进行扩展，计算新的子节点的半径。
Figure PCTCN2017091964-appb-000030
其中d'2 k表示子节点半径，随着译码深度的加深，球半径越来越小。
S7：保存该球半径中的全部节点{bk}，跳至S4。
S8：译码输出。如此反复进行，当球半径内的所有节点都到达输入信息的最后一个符号，从筛选出的多条路径中找出距离最小的一组作为译码的最终输出结果。
当然，本实施例提供的译码装置还可以包括预处理模块702，用于根据获取的数字信号进行预处理。预处理包括同步处理、信道估计均衡处理、数字化处理、切割处理中的一种或多种。译码模块703用于根据预处理后的信号进行译码。
具体的，预处理可以采用现有技术中的任意一种可行的方式，本实施例不再对其进行赘述。
实施例三
本实施例提供了一种基于重叠复用的调制解调方法，包括调制步骤和解调步骤。本实施例中，主要以基于重叠时分复用的调制解调进行说明。
如图12所示，调制步骤包括下面子步骤：
步骤2.1：根据设计参数生成在时域内的初始包络波形h(t)。
在生成初始包络波形时，可以通过用户输入设计参数，以实现在实际系统中根据系统性能指标灵活配置。
在某些实施例中，当初始包络波形的旁瓣衰减已经确定时，设计参数包括初始包络波形的窗长度L，例如当初始包络波形为巴特莱特包络波形时。
在某些实施例中，设计参数包括初始包络波形的窗长度L和旁瓣衰减r，例如当初始包络波形为切比雪夫包络波形时。
当然，当初始包络波形为其他形式时，可以根据相应初始包络波形的特点确定设计参数。
步骤2.2：根据重叠复用次数K将初始包络波形在相应域(本实施例中为时域)内按预定的移位间隔进行移位，以得到各固定间隔的移位包络波形h(t-i*△T)。
其中，移位间隔为时间间隔△T，时间间隔△T为：△T＝L/K。此时，信号的符号宽度即为△T。
另外，还需要保证△T不小于系统采样率的倒数。
i的取值与输入符号长度N有关，且i取0到N-1的整数。例如，当N＝8时，i取0至7的整数。
步骤2.3：将输入的信号数字序列转换成正负符号表示的信号符号序列。
具体的，将输入的数字信号序列中的0转换为+A，1转换为-A，A取值为非0任意数，以得到正负符号序列。例如，取A为1时，将输入的{0,1}比特序列经过BPSK(Binary Phase Shift Keying，移相键控)调制转换成{+1、-1}符号序列。
步骤2.4：将转换后的信号符号序列xi(本实施例中xi＝{+1+1-1-1-1+1-1+1})与各固定间隔的移位包络波形h(t-i*△T)相乘，以得到各调制包络波形xi h(t-i*△T)。
步骤2.5：将各调制包络波形xi h(t-i*△T)在相应域(本实施例中为时域)上进行叠加，以得到携带输入信号序列的复调制包络波形，即发送的信号。
发送的信号可以如下表示：
Figure PCTCN2017091964-appb-000031
步骤2.6：将得到的复调制包络波形作为发送信号发射出去。
故，本实施例中，A取值为1时，叠加后的输出符号(输出的信号符号序列)即为：s(t)＝{+1+2+1-1-3-1-1+1}。
请参考图13，为K路波形复用的原理示意图，其呈平行四边形形状。其中，每一行表示一个所要发送的符号xi与相应时刻的包络波形h(t-i*△T)相乘后得到的待发送信号波形xih(t-i*△T)。a0～ak-1表示对每个窗函数波形(包络波形)进行K次分段得到的每部分的系数值，具体为关于幅度值的系数。
由于将输入的数字信号序列转换成正负符号序列时，将输入的数字信号序 列中的0,1转换为±A，A取值为非0任意数以得到正负符号序列。例如，A取值为1时，将输入的{0,1}比特序列经过BPSK调制转换成{+1、-1}符号序列，以得到正负符号序列。所以图12所示即为K路波形的符号叠加过程原理示意图。图14叠加过程中，第1行左边3个数表示第1个输入符号+1，第2行左边3个数表示第2个输入符号+1，第3行左边3个数表示第3个输入符号-1，第1行中间3个数表示第4个输入符号-1，第2行中间3个数表示第5个输入符号-1，第3行中间3个数表示第6个输入符号+1，第1行右边3个数表示第7个输入符号-1，第2行右边3个数表示第8个输入符号+1。因此，三个波形叠加后，得到的输出符号为{+1+2+1-1-3-1-1+1}。
当然，如果输入符号的长度为其他数值时，可以按照图13和图14所示的方式进行叠加，以得到输出符号。
本实施例中，解调步骤包括：接收复调制包络波形；根据复调制包络波形获取携带有输入信息的数字信号；基于球译码算法对数字信号在相应域内进行译码，得到最佳译码路径，以进行判决输出。
解调步骤中的译码方法采用上述实施例一提供的译码方法，此处不再对其进行赘述。
实施例四
请参考图3，基于上述实施例三提供的基于重叠复用的调制解调方法，本实施例相应提供了一种基于重叠复用的调制解调系统，包括发射机和接收机。
发射机包括调制装置和发射装置，请结合参考图15，调制装置包括波形生成模块801、移位模块802、调制模块803、乘法模块804和叠加模块805。
波形生成模块801用于生成初始包络波形。本实施例中，主要以基于重叠时分复用的调制解调进行说明。其根据设计参数生成在时域内的初始包络波形h(t)。
在生成初始包络波形时，可以通过用户输入设计参数，以实现在实际系统中根据系统性能指标灵活配置。
在某些实施例中，当初始包络波形的旁瓣衰减已经确定时，设计参数包括初始包络波形的窗长度L，例如当初始包络波形为巴特莱特包络波形时。
在某些实施例中，设计参数包括初始包络波形的窗长度L和旁瓣衰减r，例如当初始包络波形为切比雪夫包络波形时。
当然，当初始包络波形为其他形式时，可以根据相应初始包络波形的特点确定设计参数。
移位模块802用于根据重叠复用次数将初始包络波形在相应域(本实施例中为时域)内按移位间隔进行移位，以得到各固定间隔的移位包络波形h(t-i*△T)。
其中，移位间隔为时间间隔△T，时间间隔△T为：△T＝L/K。此时，信号的符号宽度即为△T。
另外，还需要保证△T不小于系统采样率的倒数。
i的取值与输入符号长度N有关，且i取0到N-1的整数。例如，当N＝8时，i取0至7的整数。
调制模块803用于将输入的信号数字序列转换成正负符号表示的信号符号序列。
具体的，将输入的数字信号序列中的0转换为+A，1转换为-A，A取值为非0任意数，以得到正负符号序列。例如，取A为1时，将输入的{0,1}比特序列经过BPSK(Binary Phase Shift Keying，移相键控)调制转换成{+1、-1}符号序列。
乘法模块804用于将信号符号序列xi与各固定间隔的移位包络波形h(t-i*△T)相乘，以得到各调制包络波形xi h(t-i*△T)。
叠加模块805用于将各调制包络波形xi h(t-i*△T)在相应域(本实施例中为时域)上进行叠加，以得到携带输入信号序列的复调制包络波形，即发送的信号。
发送的信号可以如下表示：
Figure PCTCN2017091964-appb-000032
发射装置用于将复调制包络波形作为发送信号发射出去。
接收机包括用于接收复调制包络波形的接收装置和上述实施例二提供的任意一种基于重叠复用的译码装置，本实施不再对其进行赘述。
本申请实施例提供的基于重叠复用的译码方法、装置及调制解调方法和系统，基于球译码算法对数字信号在相应域内进行译码，得到最佳译码路径，以进行判决输出。基于球译码算法进行译码，简化了译码过程，节省了系统资源，降低了译码复杂度，同时提高译码输出的实时性并保证了系统的性能。从而实现了随着重叠复用次数的增加，译码复杂度较低。同时又能在保证较好的译码性能的前提下，使得重叠复用次数较大的译码方法能够实用化。
需要说明的是，本申请实施例提供的基于重叠复用的译码方法、装置及调 制解调方法和系统可以应用到移动通信、卫星通信、微波视距通信、散射通信、大气层光通信、红外通信、水声通信等无线通信系统中，既可以应用于大容量无线传输，也可以应用于小容量的轻型无线电系统。
本领域技术人员可以理解，上述实施方式中各种方法的全部或部分步骤可以通过程序来控制相关硬件完成，该程序可以存储于一计算机可读存储介质中，存储介质可以包括：只读存储器、随机存取存储器、磁盘或光盘等。
以上内容是结合具体的实施方式对本申请所作的进一步详细说明，不能认定本申请的具体实施只局限于这些说明。对于本申请所属技术领域的普通技术人员来说，在不脱离本申请发明构思的前提下，还可以做出若干简单推演或替换。

Claims (10)

  1. 一种基于重叠复用的译码方法，其特征在于，包括：
    获取携带有输入信息的数字信号；
    基于球译码算法对所述数字信号在相应域内进行译码，得到最佳译码路径，以进行判决输出；具体包括：预先设定一个搜索半径，对球内格点循环搜索，不断减小搜索半径，直至找完球半径内的所有路径，并至少找到了一条完整路径，完成译码。
  2. 如权利要求1所述的方法，其特征在于，基于球译码算法对所述数字信号在相应域内进行译码，得到最佳译码路径，以进行判决输出，包括：
    找到一组码序列
    Figure PCTCN2017091964-appb-100001
    作为判决输出，使其满足
    Figure PCTCN2017091964-appb-100002
    且满足||y-Hb||2≤d2；
    其中，b为所述输入信息，且b∈UM*1，U为一有限字符集，y为所述数字信号，且y可以表示为y＝Hb，y∈UM*1是接收向量，H∈UN*M是信道矩阵，d为球译码半径，其中M，N分别为信道矩阵的列数和行数。
  3. 如权利要求2所述的方法，其特征在于，基于球译码算法对所述数字信号在相应域内进行译码，得到最佳译码路径，以进行判决输出，包括：
    对信道矩阵进行分解；
    将分解后的信道矩阵代入||y-Hb||2≤d2，并逐渐缩小球译码半径，经过反复寻找球内格点，确定最佳译码路径，以进行判决输出。
  4. 如权利要求3所述的方法，其特征在于，对信道矩阵进行分解包括对信道矩阵进行乔里斯基分解或QR分解；基于球译码算法对所述数字信号在相应域内进行译码包括根据公式d2＝αNδ2设定球译码半径大小，数据长度等于N，δ2为噪声方差，α为半径系数。
  5. 一种基于重叠复用的译码装置，其特征在于，包括：
    获取模块，用于获取携带有输入信息的数字信号；
    译码模块，用于基于球译码算法对所述数字信号在相应域内进行译码，得到最佳译码路径，以进行判决输出；具体为：译码模块用于预先设定一个搜索半径，对球内格点循环搜索，不断减小搜索半径，直至找完球半径内的所有路径，并至少找到了一条完整路径，完成译码。
  6. 如权利要求5所述的装置，其特征在于，译码模块用于基于球译码算法对所述数字信号在相应域内进行译码，得到最佳译码路径，以进行判决输出时：
    译码模块用于找到一组码序列
    Figure PCTCN2017091964-appb-100003
    作为判决输出，使其满足
    Figure PCTCN2017091964-appb-100004
    且满足||y-Hb||2≤d2；
    其中，b为所述输入信息，且b∈UM*1，U为一有限字符集，y为所述数字信号，且y可以表示为y＝Hb，y∈UM*1是接收向量，H∈UN*M是信道矩阵，d为球译码半径，其中M，N分别为信道矩阵的列数和行数。
  7. 如权利要求6所述的装置，其特征在于，译码模块用于基于球译码算法对所述数字信号在相应域内进行译码，得到最佳译码路径，以进行判决输出时：
    译码模块用于对信道矩阵进行分解，将分解后的信道矩阵代入||y-Hb||2≤d2，并逐渐缩小球译码半径，经过反复寻找球内格点，确定最佳译码路径，以进行判决输出。
  8. 如权利要求7所述的装置，其特征在于，译码模块用于对信道矩阵进行乔里斯基分解或QR分解；并根据公式d2＝αNδ2设定球译码半径大小，数据长度等于N，δ2为噪声方差，α为半径系数。
  9. 一种基于重叠复用的调制解调方法，其特征在于，包括调制步骤和解调步骤：
    调制步骤包括：
    生成初始包络波形；
    根据重叠复用次数将初始包络波形在相应域内按移位间隔进行移位，以得到各固定间隔的移位包络波形；
    将输入的信号数字序列转换成正负符号表示的信号符号序列；
    将信号符号序列与偏移后各固定间隔的移位包络波形相乘，以得到各调制包络波形；
    将各调制包络波形在相应域上进行叠加，以得到携带所述信号数字序列的复调制包络波形；
    将所述复调制包络波形发射出去；
    解调步骤包括：
    接收所述复调制包络波形；
    根据所述复调制包络波形获取携带有输入信息的数字信号；
    基于球译码算法对所述数字信号在相应域内进行译码，得到最佳译码路径，以进行判决输出；具体包括：预先设定一个搜索半径，对球内格点循环搜索，不断减小搜索半径，直至找完球半径内的所有路径，并至少找到了一条完整路径，完成译码。
  10. 一种基于重叠复用的调制解调系统，其特征在于，包括发射机和接收机；
    所述发射机包括调制装置和发射装置，所述调制装置包括：
    波形生成模块，用于生成初始包络波形；
    移位模块，用于根据重叠复用次数将初始包络波形在相应域内按移位间隔进行移位，以得到各固定间隔的移位包络波形；
    调制模块，用于将输入的信号数字序列转换成正负符号表示的信号符号序列；
    乘法模块，用于将信号符号序列与偏移后各固定间隔的移位包络波形相乘，以得到各调制包络波形；
    叠加模块，用于将各调制包络波形在相应域上进行叠加，以得到携带输入信号序列的复调制包络波形；
    所述发射装置用于将所述复调制包络波形发射出去；
    所述接收机包括用于接收所述复调制包络波形的接收装置和如权利要求4-8任一项所述的译码装置。
PCT/CN2017/091964 2016-10-25 2017-07-06 基于重叠复用的译码方法、装置及调制解调方法和系统 WO2018076773A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201610934481.2 2016-10-25
CN201610934481.2A CN107979440B (zh) 2016-10-25 2016-10-25 基于重叠复用的译码方法、装置及调制解调方法和系统

Publications (1)

Publication Number Publication Date
WO2018076773A1 true WO2018076773A1 (zh) 2018-05-03

Family

ID=62004857

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2017/091964 WO2018076773A1 (zh) 2016-10-25 2017-07-06 基于重叠复用的译码方法、装置及调制解调方法和系统

Country Status (2)

Country Link
CN (1) CN107979440B (zh)
WO (1) WO2018076773A1 (zh)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111817834A (zh) * 2020-05-14 2020-10-23 北京中电飞华通信有限公司 无线通信系统及其时域、频域资源复用方法
CN114268527A (zh) * 2021-12-30 2022-04-01 天津光电通信技术有限公司 一种基于大数判决的数字通信方法及系统
CN114500205A (zh) * 2022-01-25 2022-05-13 新诺北斗航科信息技术（厦门）股份有限公司 Ais信号的译码方法、译码装置及存储介质

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111526105B (zh) * 2020-04-19 2021-07-27 华中科技大学 高频谱效率频分复用系统的子载波干扰补偿方法及装置
CN113438191B (zh) * 2021-06-23 2023-06-30 安徽师范大学 一种sm-scma系统上行链路的零码字辅助球形译码方法、系统

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008006246A1 (fr) * 2006-07-06 2008-01-17 Daoben Li Procédé et système de multiplexage temporel
CN101388672A (zh) * 2008-10-22 2009-03-18 山东大学 一种针对重叠编码复用的改进球形译码算法
CN101557364A (zh) * 2009-05-12 2009-10-14 山东大学 Turbo-OvCDM系统的联合迭代信道估计和译码方法
CN101562464A (zh) * 2009-05-18 2009-10-21 北京天碁科技有限公司 一种基于深度优先搜索的球形译码检测方法
CN101860497A (zh) * 2010-05-24 2010-10-13 北京科技大学 一种利用改进球译码算法实现fbmc系统的均衡的方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008006246A1 (fr) * 2006-07-06 2008-01-17 Daoben Li Procédé et système de multiplexage temporel
CN101388672A (zh) * 2008-10-22 2009-03-18 山东大学 一种针对重叠编码复用的改进球形译码算法
CN101557364A (zh) * 2009-05-12 2009-10-14 山东大学 Turbo-OvCDM系统的联合迭代信道估计和译码方法
CN101562464A (zh) * 2009-05-18 2009-10-21 北京天碁科技有限公司 一种基于深度优先搜索的球形译码检测方法
CN101860497A (zh) * 2010-05-24 2010-10-13 北京科技大学 一种利用改进球译码算法实现fbmc系统的均衡的方法

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111817834A (zh) * 2020-05-14 2020-10-23 北京中电飞华通信有限公司 无线通信系统及其时域、频域资源复用方法
CN111817834B (zh) * 2020-05-14 2023-06-09 北京中电飞华通信有限公司 无线通信系统及其时域、频域资源复用方法
CN114268527A (zh) * 2021-12-30 2022-04-01 天津光电通信技术有限公司 一种基于大数判决的数字通信方法及系统
CN114500205A (zh) * 2022-01-25 2022-05-13 新诺北斗航科信息技术（厦门）股份有限公司 Ais信号的译码方法、译码装置及存储介质
CN114500205B (zh) * 2022-01-25 2023-08-15 新诺北斗航科信息技术（厦门）股份有限公司 Ais信号的译码方法、译码装置及存储介质

Also Published As

Publication number Publication date
CN107979440B (zh) 2021-10-26
CN107979440A (zh) 2018-05-01

Similar Documents

Publication Publication Date Title
WO2018076773A1 (zh) 基于重叠复用的译码方法、装置及调制解调方法和系统
WO2018068540A1 (zh) 基于重叠复用的调制解调方法和装置
CN106899376B (zh) 物理层网络编码连续相位调制信号的非相干检测方法
WO2017174003A1 (zh) 定时同步方法和装置
US10771303B2 (en) Overlapped multiplexing-based decoding method and device, and modulation and demodulation method and system
CN107124194B (zh) 海上数字中频发射设备
Necker et al. Totally blind channel estimation for OFDM over fast varying mobile channels
CN107612860B (zh) 适用于802.11ac接收机的同步与下采样估计方法
US20190229838A1 (en) Fast decoding method and device suitable for ovxdm system, and ovxdm system
CN107276703B (zh) 一种采用压缩感知技术的正交空间调制系统检测方法
WO2018019109A1 (zh) 基于重叠复用的译码方法、装置和系统
US10419261B2 (en) Decoding method and apparatus, and system therefor
WO2018014733A1 (zh) 一种适用于OvXDM系统译码方法、装置及OvXDM系统
CN107645359B (zh) 一种OvXDM系统的快速译码方法、装置及OvXDM系统
Zhang et al. Decoding overlapped time division multiplexing system with Fano algorithm
Tibenderana et al. Low-complexity high-performance GFSK receiver with carrier frequency offset correction
WO2018019110A1 (zh) 基于OvXDM系统的均衡译码方法、装置和系统
CN104113499B (zh) 一种基于概率排序的低复杂度存储空间约束检测方法
CN107645363B (zh) 一种适用于OvXDM系统的快速译码方法、装置及OvXDM系统
CN116708093A (zh) 多输入多输出系统的检测方法和装置、设备、介质
CN106911423A (zh) 译码方法、装置及其系统
CN116708094A (zh) 多输入多输出系统的检测方法和装置、设备、介质
KR101498267B1 (ko) 미모 시스템의 신호 복구를 위한 스피어 디코딩 방법 및 그 시스템
CN115243316A (zh) 一种LoRa网络数据聚合的实现方法与装置
Hussain et al. Wavelet shift keying based digital transmission

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17864122

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC (EPO FORM 1205A DATED 27.09.2019)

122 Ep: pct application non-entry in european phase

Ref document number: 17864122

Country of ref document: EP

Kind code of ref document: A1