Specific embodiment
The present invention is described in further detail below by specific embodiment combination accompanying drawing.
In to overlapping time-division multiplex technology research, inventor has found that the growth of transimission power is main with being re-used
The frequency spectrum of signal (modulating window function) is relevant, not as contemplated by theory to multiplexed signals frequency spectrum
Shape, bandwidth have no requirement.Although there are many window functions in the prior art, can freely adopt in theory
With various window functions to transmission symbol be modulated, but due to rectangular window compared to other window functions produce,
Design and application it is upper be easier, cost it is lower, therefore preferentially use rectangular window when signal modulation is carried out at present,
And the spectral bandwidth of square wave is wider, multiplexing waveform systematic function is very poor, causes required transimission power and mistake
Code check is all very high.
Based on above-mentioned discovery, in embodiments of the present invention, in application overlapped time division multiplexing technology using one kind
Window function better than square wave is modulated to the digital signal sequences being input into.
Fig. 3 is refer to, overlapped time division multiplexing system includes signal transmitter A01 and receiver A02.
Emitter A01 includes overlapped time division multiplexing modulating device 101 and emitter 102.Overlap the time-division multiple
It is used to generate the multiple modulation envelope waveform for carrying output signal sequence with modulating device 101;Emitter 102
For the multiple modulation envelope waveform to be transmitted into receiver A02.
Receiver A02 includes reception device 201 and sequence detecting apparatus 202.Reception device 201 is used to connect
The multiple modulation envelope waveform of the transmitting-receiving transmitting of injection device 102;Sequence detecting apparatus 202 are used for the polyphony to receiving
Envelope waveform processed carries out the data sequence detection in time domain, to make decisions output.
Preferably, receiver A02 also includes being arranged between reception device 201 and sequence detecting apparatus 202
Pretreatment unit 203, receive digital signal sequences for aiding in forming the synchronous of each frame in.
In emitter A01, the digital signal sequences of input pass through the shape of overlapped time division multiplexing modulating device 101
Into the overlapped transmission signal in time domain of multiple symbols, then the transmission signal is sent out by emitter 102
It is mapped to receiver A02.The signal of the transmitting of 201 receiving and transmitting unit of reception device 102 of receiver A02,
Forming suitable sequence detecting apparatus 202 by pretreatment unit 203 detect the data signal of reception, sequence
The docking collection of letters number of row detection means 202 carries out the data sequence detection in time domain, so as to export judgement.
Fig. 4 is refer to, overlapped time division multiplexing modulating device 101 (OvTDM modulating devices) is given birth to including waveform
Into module 301, shift module 302, multiplier module 303 and laminating module 304.
Waveform generating module 301 is used for according to the design parameter generation initial Envelop waves that waveform is smoothed in time domain
Shape.
Shift module 302 is used to that initial envelope waveform to be pressed into predetermined shifting in time domain according to overlapping multiplexing number of times
Bit interval is shifted, to obtain the skew envelope waveform of each moment sending signal.
Modulation module 305 is used to for the digital signal sequences of input to be converted into sign symbol sequence.
Multiplier module 303 is used for each moment sending signal after the sign symbol sequence after conversion and skew
Skew envelope waveform is multiplied, to obtain the modulation envelope waveform at each moment.
Laminating module 304 is used to be overlapped the modulation envelope waveform at each moment in time domain, to obtain
Carry the multiple modulation envelope waveform of output signal sequence.
With reference to overlapped time division multiplexing modulator approach, overlapped time division multiplexing modulating device 101 is done further
Illustrate, overlapped time division multiplexing modulator approach includes below step:
(1) waveform generating module 301 generates the smooth initial Envelop waves of waveform in time domain according to design parameter
Shape h (t).
When initial envelope waveform is generated, can be by user input design parameter, to realize in real system
It is middle according to system performance index flexible configuration.
In certain embodiments, when the side lobe attenuation of initial envelope waveform has determined, design parameter includes
The window length L of initial envelope waveform, such as when initial envelope waveform is Bart's Lay spy's envelope waveform.
In certain embodiments, design parameter includes the window length L and side lobe attenuation r of initial envelope waveform, example
Such as when initial envelope waveform is Chebyshev's envelope waveform.
Certainly, when initial envelope waveform is other forms, can be according to the characteristics of corresponding initial envelope waveform
Determine design parameter.
(2) initial envelope waveform is pressed predetermined by shift module 302 according to overlapping multiplexing number of times K in time domain
Shift intervals are shifted, to obtain the skew envelope waveform h (t-i* △ T) of each moment sending signal.
Wherein, shift intervals are for time interval △ T, time interval △ T:△ T=L/K.
In addition, in addition it is also necessary to ensure inverses of the △ T not less than systematic sampling rate.
The value of i is relevant with incoming symbol length N, and i takes 0 to N-1 integer.For example, working as N=8
When, i takes 0 to 7 integer.
(3) digital signal sequences of input are converted into sign symbol sequence by modulation module 305.
Specifically, 0 in the digital signal sequences of input is converted to+A by modulation module 305,1 is converted to-A,
To obtain sign symbol sequence.For example, taking A=1, { 0, the 1 } bit sequence that will be input into is by BPSK (Binary
Phase Shift Keying, phase-shift keying) modulation conversion is into {+1, -1 } symbol sebolic addressing.
(4) multiplier module 303 is by the sign symbol sequence x after conversioniWith each moment sending signal after skew
Skew envelope waveform h (t-i* △ T) be multiplied, to obtain the modulation envelope waveform x at each momenti h(t-i*△T)。
(5) laminating module 304 is by the modulation envelope waveform x at each momentiH (t-i* △ T) is folded in time domain
Plus, to obtain carrying the multiple modulation envelope waveform of output signal sequence, that is, the signal for sending.
The signal of transmission can be expressed as below:
Because the time domain waveform of initial envelope waveform is smoother, frequency domain bandwidth is narrower, and the waveform after superposition is relatively put down
Slide and be limited in narrower bandwidth, therefore improve the availability of frequency spectrum and transmission rate of system, reduce system
The bit error rate.
Fig. 5 is refer to, specifically, overlapped time division multiplexing modulating device 101 can be realized by following hardware cell.
Overlapped time division multiplexing modulating device 101 includes digital waveform generator 401, shift register 402, modulator
403rd, multiplier 404 and adder 405.
First cophase wave of initial envelope waveform is formed by digital waveform generator 401 in a digital manner first
Shape, the initial envelope waveform is smoothed in time domain;Again by shift register 402 by digital waveform generator 401
The phase wiggles of the first initial envelope waveform for producing are shifted, to produce each moment sending signal
Skew envelope waveform;Then, the digital signal sequences of input are converted into sign symbol sequence by modulator 403,
Multiplier 404 is then by the skew envelope of each moment sending signal after the sign symbol sequence after conversion and skew
Waveform is multiplied, to obtain the modulation envelope waveform at each moment;It is last by adder 405 by each moment
Modulation envelope waveform is overlapped in time domain, to obtain carrying the multiple modulation envelope waveform of output signal sequence,
Form transmission signal.
Fig. 6 is refer to, is the block diagram of the pretreatment unit 203 of receiver A02 in the embodiment of the present invention.
Pretreatment unit 203 includes synchronizer 501, channel estimator 502 and digital processor 503.Its
The docking collection of letters number of middle synchronizer 501 forms a symbol time synchronization in receiver;Then channel estimator 502
Channel parameter is estimated;Digital processor 503 is digitized place to the reception signal of each frame in
Reason, so that forming suitable sequence detecting apparatus carries out the digital signal sequences of Sequence Detection reception.
Fig. 7 is refer to, is the block diagram of the sequence detecting apparatus 202 of receiver A02 in the embodiment of the present invention.
Sequence detecting apparatus 202 include that analytic unit memory 601, comparator 602 and multiple surviving paths are deposited
Reservoir 603 and Euclidean distance memory 604 or weighted euclidean distance memory (not shown).In detection
During, the complex convolution encoding model that analytic unit memory 601 makes overlapped time division multiplexing system is passed
Shape figure, and whole states of overlapped time division multiplexing system are listed, and store;And comparator 602 is according to analysis
Trellis structure in cell memory 601, searches out and receives data signal minimum Eustachian distance or weighting minimum
The path of Euclidean distance;And surviving path memory 603 and Euclidean distance memory 604 or weighted Euclidean away from
Then be respectively used to store from memory the surviving path and Euclidean distance or weighted Euclidean of the output of comparator 602 away from
From.Wherein, surviving path memory 603 and Euclidean distance memory 604 or weighted euclidean distance memory
Need respectively to prepare one for each stable state.The length of surviving path memory 603 can be preferably 4K~
5K.Euclidean distance memory 604 or weighted euclidean distance memory are preferably only storage relative distance.
In the present embodiment, initial envelope waveform is kayser (Kaiser) envelope waveform or its bag for developing window function
Network waveform.
Then with initial envelope waveform as kayser, (Kaiser) envelope waveform is described further to the application below.
Wherein, overlapping multiplexing number of times K=3, incoming symbol length N=8, incoming symbol xi={+1+1-1-1-1+1-1
+ 1 } illustrate that the signal of OvTDM sends and receives process as a example by.Wherein, incoming symbol length refers to send
The length of one frame signal.
Fig. 5 is refer to, signal generation process includes below step:
(1) kayser (Kaiser) envelope waveform h (t) of sending signal is generated according to design parameter first.
In the present embodiment in design parameter, window length L=63, beta are respectively 0.5,2,5, its time domain waveform
With frequency-domain waveform as shown in Figure 8.As can be seen from Figure 8, with the increase of beta, time domain waveform rises
Point gradually levels off to 0, and waveform is increasingly smoothed;Frequency-domain waveform side lobe attenuation is faster, therefore is folded in later step
Plus after performance it is more excellent.Respectively illustrated in Fig. 8 beta for 0.5,2,5 when, kayser (Kaiser) window
Time domain waveform and frequency-domain waveform.
Specifically, for kayser (Kaiser) window function, it can be represented by formula below:
Wherein, I0(β) be the first kind deformation zero Bessel function, β is the form parameter of window function, its by
Following formula determines:
α is the difference (dB) between the main lobe value and side lobe levels of kayser (Kaiser) window function, changes β's
Value, can carry out unrestricted choice to producing valve width and side lobe attenuation.β value is bigger, the secondary lobe of window function frequency spectrum
Value is just smaller, and its main lobe width is wider.It should be noted that the n only representation formulas in above-mentioned formula
In function variable.
(2) kayser (Kaiser) envelope waveform h (t) designed by (1) is pressed into predetermined displacement in time domain
Interval is shifted, wherein, shift intervals are time interval △ T (△ T=L/K=21).After displacement, shape
Skew envelope waveform h (t-i* △ T) into each moment sending signal is (because N=8, therefore i are integer and take
Be worth for 0~7), the skew envelope waveform figure of each moment sending signal is as shown in Figure 9 after displacement.
(3) digital signal sequences of input are converted into sign symbol sequence.
Specifically, 0 in the digital signal sequences of input can be converted into+A, 1 is converted to-A, to obtain
Sign symbol sequence.For example, take A=1, { 0, the 1 } bit sequence that will be input into by BPSK modulation conversions into
{+1, -1 } symbol sebolic addressing.
(4) by sign symbol sequence xi(x in the present embodimenti={+1+1-1-1-1+1-1+1 }) and (2)
The skew envelope waveform h (t-i* △ T) of each moment sending signal of generation is multiplied, and obtains the modulation at each moment
Envelope waveform xih(t-i*△T);Shown in waveform such as Figure 10 (Figure 10 A~Figure 10 C) after formation, wherein three
Different dotted lines represents three oscillograms after being multiplied.
(5) the modulation envelope waveform x at each moment for being formed (4)iH (t-i* △ T) is carried out in time domain
Superposition, to obtain carrying the multiple modulation envelope waveform of output signal sequence, that is, the signal for sending.Transmission signal
Oscillogram is as shown in the solid line waveform in Figure 10.
The signal of transmission can be expressed as:
Specifically, output signal sequence is determined by following mode:
When modulation envelope waveform is multiplied by plus sign with the moment envelope waveform to be obtained, the modulation envelope ripple is made
The operation values of shape are+1, when modulation envelope waveform is multiplied by minus symbol with the moment envelope waveform to be obtained, order
The operation values of the modulation envelope waveform are -1.For each shift intervals, the tune in the shift intervals will be located at
The operation values superposition of envelope waveform processed, draws the output signal of the shift intervals, so as to form output signal sequence
Row.
Therefore, in the present embodiment, the output symbol (output signal sequence) after superposition is:S (t)={+1+2+1
-1-3-1-1+1}。
Figure 11 is refer to, is the principle schematic of K roads waveform multiplexing, its parallelogram shape.Wherein,
A symbol x to be sent is represented per a lineiObtained after being multiplied with the envelope waveform h (t-i* △ T) at corresponding moment
Signal waveform x to be sentih(t-i*△T)。a0~ak-1Expression is carried out to each window function waveform (envelope waveform)
The coefficient value for being segmented the every part for obtaining K times, the specially coefficient on range value.
During due to the digital signal sequences of input being converted into sign symbol sequence, the data signal sequence that will be input into
In row 0 is converted to+1,1 is converted to -1, to obtain sign symbol sequence.For example, { 0,1 } that will be input into
Bit sequence by BPSK modulation conversions into {+1, -1 } symbol sebolic addressing, to obtain sign symbol sequence.So
The symbol additive process principle schematic of K roads waveform is shown in Figure 12.In Figure 12 additive processes, the 1st
The number of the row left side 3 represents the 1st incoming symbol+1, and the number of the 2nd row left side 3 represents the 2nd incoming symbol
+ 1, the number of the 3rd row left side 3 represents that 3 numbers represent the 4th in the middle of the 3rd incoming symbol -1st, the 1st row
3 numbers represent that 3 numbers are represented in the middle of the 5th incoming symbol -1st, the 3rd row in the middle of incoming symbol -1, the 2nd row
6th incoming symbol+1,3 numbers of the 1st row the right represent the 7th incoming symbol -1st, the 2nd row the right 3
Number represents the 8th incoming symbol+1.Therefore, after three addition of waveforms, the output symbol for obtaining is {+1+2
+1-1-3-1-1+1}。
Certainly, if the length of incoming symbol is other numerical value, can be according to shown in Figure 11 and Figure 12
Mode is overlapped, to obtain output symbol.
, in beta=0.5, by 0.94, the waveform after superposition is for its time domain for kayser (Kaiser) window
Square wave is compared to smooth, and frequency domain side lobe decay compares square wave soon, frequency domain bandwidth is narrower so that after superposition
Waveform frequency spectrum efficiency it is higher, the transimission power needed for sending signal is relatively low.And kayser (Kaiser) window beta
Numerical value can be designed according to system performance index with oneself, with the increase of beta, the waveform after superposition can be more
Come more smooth, the power needed for transmission signal is more and more lower in systems in practice, and coding/decoding capability can be increasingly
By force, design flexible compared with square wave.
Fig. 6 and Fig. 7 is refer to, signal receives process includes below step:
(1) the docking collection of letters number first is synchronized, including the synchronization of carrier synchronization, frame synchronization, symbol time etc..
(2) according to sampling theorem, the reception signal to each frame in is digitized treatment.
(3) waveform for receiving is cut according to waveform transmission time interval.
(4) the data sequence detection in time-domain is carried out to the signal for receiving, to make decisions output, that is, is pressed
Row decoding is entered to the waveform after cutting according to certain decoding algorithm.
By after the pre-treatment step of above-mentioned (1)~(2), the reception symbol sebolic addressing obtained after waveform cutting is:
S (t)={+1+2+1-1-3-1-1+1 }, to symbol sebolic addressing according to the tree graph and figure of Fig. 7 Input output Relationships
8 node state transfer relationship figures, carry out between symbol before and after compare, obtain node transfer path.
In Figure 13, upward branch is+1 input, and downward branch is -1 input.The tree after the 3rd
Figure reforms into repetition, because the branch that every node from labeled as a gives off has same output,
The conclusion is equally applicable to node b, c, d.They nothing more than being several possibility as shown in figure 14, from
It can be seen that (through input+1) node a and (through input -1) node b can only be transferred to from node a in Figure 14, together
When b can only arrive (input+1) c and (input -1) d, c and can only arrive (input+1) a and (being input into -1) b, d can only arrive (defeated
Enter+1) c and (input -1) d.The reason for producing this phenomenon is very simple, because only that adjacent K is (specific to this example
It is that 3) individual symbol can just be formed and interfered.So when K data are input to channel, for coming earliest
1 data has moved out a shift unit of rightmost.Therefore the output of channel is except depending on current moment
The input of data, further depends on the input of preceding K-1 data.
Such as blackening shown in thick line in Figure 13, first due to s (t) accords with for node state transfer in present case
Number be+1, so node transfer path is:+1->a->a->b->d->d->c->b->C, according to this turn
The symbol sebolic addressing that shifting relation can obtain input is {+1+1-1-1-1+1-1+1 }.
In the present embodiment, because kayser (Kaiser) envelope waveform is smoother in time domain, and side lobe attenuation compared with
Hurry up, therefore required transimission power is relatively low, precision is higher when being cut to waveform, the symbol sequence for receiving
The row degree of accuracy is more preferable.
Figure 15 is refer to, is the time domain and frequency-domain waveform figure of square wave.When initial envelope waveform selects square wave
During envelope waveform, then the oscillogram after each signal generated according to above-mentioned signal generation process and superposition is such as
Shown in Figure 16, wherein three different dotted lines represent three oscillograms, solid line represents the oscillogram after superposition.
As can be seen from Figure 16, square wave in time domain by 1, and broader bandwidth, on frequency domain
Side lobe attenuation is slow, therefore waveform after time domain superposition is unsmooth, and frequency domain bandwidth is wider, useful signal and nothing
Effect signal is difficult to differentiate between so that transimission power required during sending and receiving signal increases, and receives letter
The accuracy rate of waveform cutting and coding/decoding capability reduction during number.In systems in practice transmission rate it is identical and
In the case of spectrum efficiency identical, required transimission power and the bit error rate are all very high during using square wave.
But kayser (Kaiser) window used in the present embodiment waveform after time domain superposition is smooth compared with square wave,
Side lobe attenuation is very fast, frequency domain bandwidth is narrower, improves the accuracy rate and encoding-decoding process of waveform cutting process
Error correcting capability, reduces the transimission power of signal so that in the timing of spectrum efficiency one, use relatively low transmission
Power can just reach transmission rate very high.The numerical value of kayser (Kaiser) window beta can be with oneself according to being again
System performance indications design, with the increase of beta, the waveform after superposition can be smoothed increasingly, in real system
Power needed for middle transmission signal is more and more lower, and coding/decoding capability can be increasingly stronger, designs flexible compared with square wave.
In addition, in other embodiments, initial envelope waveform is also an option that various with kayser (Kaiser) window
Function develop function envelope waveform, including the company of kayser (Kaiser) pulse-shaping multiply, all-order derivative,
The envelope waveform of the functions such as all-order derivative sum, these envelope waveforms are same in time domain to have what waveform was smoothed
Feature, thus it is close with using kayser (Kaiser) envelope waveform using can be reached after these envelope waveforms
As effect.
The present invention provide overlapped time division multiplexing modulator approach, apparatus and system due to initial envelope waveform when
Smoothed in domain so that the waveform after superposition is smoothed, so that the transimission power of system linearly slowly increases,
Connect and improve the availability of frequency spectrum and transmission rate.The overlapped time division multiplexing modulator approach, apparatus and system can be with
It is applied to mobile communication, satellite communication, microwave horizon communication, scatter communication, atmosphere optic communication, infrared
In the wireless communication systems such as communication, underwater sound communication, Large Copacity was both can apply to and had been wirelessly transferred, it is also possible to should
For the light-duty radio system of low capacity.
It will be understood by those skilled in the art that all or part of step of various methods can in above-mentioned implementation method
To instruct related hardware to complete by program, the program can be stored in a computer-readable recording medium,
Storage medium can include:Read-only storage, random access memory, disk or CD etc..
Use above specific case is illustrated to the present invention, is only intended to help and understands the present invention, not
It is used to limit the present invention.For those skilled in the art, according to thought of the invention,
Some simple deductions, deformation can also be made or replaced.