CN102291364A - Generation method and device of quasi perfect period 16 QAM sequence - Google Patents

Abstract

The invention discloses a generation method and a device of a quasi perfect period 16 QAM (Quadrature Amplitude Modulation) sequence. The device comprises: a four-phase perfect sequence selecting unit for selecting a four-phase perfect sequence; a cyclical shift register for processing the four-phase perfect sequence with cyclical shifting to obtain a shift equivalent sequence; a first mapper for mapping the shift equivalent sequence to obtain a first sequence; a second mapper for mapping the four-phase perfect sequence to get a third sequence and a fourth sequence; and an interleaver for interleaving the third sequence and the fourth sequence to get the quasi perfect period 16 QAM sequence. Non-zero self-correlation sidelobes of period self-correlation of the quasi perfect period 16 QAM sequence are four or two pure imaginary numbers, and positions where the non-zero self-correlation sidelobes can be predetermined and are variable within certain range.

Description

The generation method and the device of accurate perfect cycle 16QAM sequence

Technical field

The present invention relates to a kind of mobile communication technology field, particularly the generation method and the device of accurate perfect cycle 16QAM sequence.

Background technology

Just towards high transfer rate, high-transmission reliability, spectral efficient, big capacity and the fast development of multimedia service direction, the technical barrier that need capture is very many for the 4th third-generation mobile communication, and one of them is exactly the transmission rate that how to improve system efficiently.In numerous possibilities, utilize M ²-qam constellation comes method of transmitting information to be subjected to people's great attention, studies show that: under same spread spectrum sequence length, and M ²Spread spectrum sequence on the-qam constellation is than traditional high several times of spread spectrum sequence transmission data bit number (M.Anand and P.V.Kumar.Low-correlation sequences overthe QAM constellation, IEEE Trans.on Inf.Theory, vol.54, no.2,2008, pp.791-810).In addition, third generation partner program (3GPP, 3 ^RdGeneration partnership project) (3GPP TS 36.211 v8.2.0 are recommended 16QAM and 64QAM in pp.62-63) as modulation symbol in its standard.On the other hand, sequence with impulse autocorrelation performance communication system synchronously in play an important role, for example, 3GPP is at LTE standard (3GPPT TS 36.211 v8.2.0, pp.57-60) in, the suggestion perfect sequence of the Zadoff-Chu of punching (being called for short the perfect sequence of ZC) (D.C.Chu, Polyphase codes with good periodiccorrelation properties.IEEE Transactions on Information Theory, vol.18, pp.531-532, July 1972) be used as main synchronizing sequence to finish the first synchronous of ofdm system, this shows that the design with sequence of impulse autocorrelation performance has substantial using value in the communications field.

Be provided with the complex-valued sequences that length is M

s＝(s(0)，s(1)，s(2)，…，s(M-1)) (1)

The periodic auto-correlation function of sequence s is defined as

$R_{s,s}\left(u\right)=\underset{k=0}{\overset{M-1}{\mathrm{\Σ}}}s\left(k\right){\left[s(k+u)\right]}^{*}\left(\right|u|\≤M-1)---\left(2\right)$

Wherein, symbol (x) ^*Expression is asked complex conjugate to x, and code element variable k+u presses mould M computing in the formula (2).

As infructescence sPeriodic auto-correlation function satisfy

So, claim sequence sThe perfect periodic sequence that is as the criterion (almost-perfect periodic sequence).

J.Wolfmann has proposed method for designing (J.Wolfmann.Almost-perfect autocorrelation sequences, IEEE Trans.on Inf.Theory, the vol.38 of the accurate perfect sequence of a class binary, no.4,1992, pp.1412-1418), 1 non-zero auto-correlation secondary lobe is only arranged; H.D.L ü ke has proposed a kind of method (H.D.L ü ke.Almost-perfect polyphase sequences with smallphase alphabet that produces the perfect sequence of heterogeneous standard, IEEE Trans.on Inf.Theory, vol.43, no.1,1997, pp.361-363), several non-zero auto-correlation secondary lobes are only arranged.But above-mentioned two kinds of methods all can not produce accurate perfect M ²-QAM sequence.

Summary of the invention

The generation method that the purpose of this invention is to provide a kind of simple, easy realization, non-zero auto-correlation secondary lobe position can pre-determine and change, auto-correlation real part have the perfect cycle 16QAM sequence of standard of impulse characteristic within the specific limits.

The generating apparatus that another object of the present invention provides a kind of simple, easy realization, non-zero auto-correlation secondary lobe position can pre-determine and change, auto-correlation real part have the perfect cycle 16QAM sequence of standard of impulse characteristic within the specific limits.

According to a first aspect of the invention, provide a kind of generation method of accurate perfect cycle 16QAM sequence, having comprised:

Select one four mutually perfect sequence;

Described four mutually perfect sequences are carried out cyclic shift handle, obtain the displacement equivalent sequence;

Described displacement equivalent sequence is shone upon processing, obtain first sequence;

Described four mutually perfect sequences are shone upon processing, obtain second sequence;

Respectively described first sequence and described second sequence are carried out the arithmetic processing, obtain the 3rd sequence and the 4th sequence;

Described the 3rd sequence and the 4th sequence are carried out interleaving treatment, obtain accurate perfect cycle 16QAM sequence.

According to a second aspect of the invention, provide a kind of generating apparatus of accurate perfect cycle 16QAM sequence, having comprised:

Four mutually perfect sequence selection unit are used to select one four mutually perfect sequence;

Circulating register carries out cyclic shift to described four mutually perfect sequences and handles, and obtains the displacement equivalent sequence;

First mapper shines upon processing to described displacement equivalent sequence, obtains first sequence;

Second mapper shines upon processing to described four mutually perfect sequences, obtains second sequence;

The arithmetic processing unit carries out the arithmetic processing to described first sequence and described second sequence respectively, obtains the 3rd sequence and the 4th sequence;

Interleaver carries out interleaving treatment with described the 3rd sequence and the 4th sequence, obtains accurate perfect cycle 16QAM sequence.

Compared with prior art, the present invention can provide a kind of the synchronous of communication system of realizing, has the accurate perfect cycle 16QAM sequence of accurate perfect cycle autocorrelation performance, and its cycle auto-correlation real part has the impulse characteristic.

The present invention is described in detail below in conjunction with accompanying drawing.

Description of drawings

Fig. 1 is the schematic diagram of the generating apparatus of accurate perfect cycle 16QAM sequence of the present invention;

Fig. 2 is the schematic diagram of instantiation of the generating apparatus of accurate perfect cycle 16QAM sequence of the present invention;

Fig. 3 is the schematic diagram that shows the generation method of accurate perfect cycle 16QAM sequence of the present invention;

Fig. 4 is mapping principle figure of the present invention;

Fig. 5 is that the length of generation of the present invention is the cycle auto-correlation mould figure of 32 accurate perfect cycle 16QAM sequence, demonstrates cycle autocorrelation function and has accurate perfect characteristic;

Fig. 6 is that length of the present invention is the cycle auto-correlation real part figure of 32 accurate perfect cycle 16QAM sequence, demonstrates cycle autocorrelation function real part and has the impulse characteristic.

Embodiment

Fig. 1 has shown the basic structure of the generating apparatus of the accurate perfect cycle 16QAM sequence of inventing, and as shown in Figure 1, the generating apparatus of accurate perfect cycle 16QAM sequence of the present invention comprises:

Four mutually perfect sequence selection unit are used to select one four mutually perfect sequence;

Circulating register carries out cyclic shift to described four mutually perfect sequences and handles, and obtains the displacement equivalent sequence;

First mapper shines upon processing to the displacement equivalent sequence, obtains first sequence;

Second mapper shines upon processing to four mutually perfect sequences, obtains second sequence;

The arithmetic processing unit carries out the arithmetic processing to described first sequence and described second sequence respectively, obtains the 3rd sequence and the 4th sequence;

Interleaver carries out interleaving treatment with described the 3rd sequence and the 4th sequence, obtains accurate perfect cycle 16QAM sequence.

Fig. 2 has shown instantiation of generating apparatus of the accurate perfect cycle 16QAM sequence of invention, and in this instantiation, device of the present invention also comprises:

Be used to preserve four mutually perfect sequence libraries of four mutually perfect sequences of different length.

16QAM sequence length and displacement are provided with the unit, are used for; 1) 16QAM sequence length 2N is set, so that four mutually perfect sequence selection unit select its sequence length to equal one the four mutually perfect sequence of N from described four mutually perfect sequence libraries, wherein N is the positive integer more than or equal to 2; 2) displacement τ is set, handles so that circulating register carries out cyclic shift τ position to described four mutually perfect sequences, wherein-N+1≤τ≤N-1 and τ ≠ 0.

As shown in Figure 2, arithmetic processing unit of the present invention can comprise:

First multiplier takes advantage of two with first sequence;

Second multiplier takes advantage of two with second sequence;

First adder carries out addition to first sequence of taking advantage of two with second sequence of not taking advantage of two and handles;

Second adder subtracts each other processing to first sequence of not taking advantage of two with second sequence of taking advantage of two;

The 3rd multiplier with taking advantage of two first sequence and not taking advantage of two the second addition of series result to multiply by 1+i, obtains the 3rd sequence;

The 4th multiplier with not taking advantage of two first sequence and the result that subtracts each other who takes advantage of two second sequence to multiply by 1-i, obtains the 4th sequence.

Arithmetic processing unit of the present invention also comprises the memory of storing constant 2, is used for respectively providing to first multiplier and second multiplier taking advantage of two constant.

Arithmetic processing unit of the present invention also comprises the memory of storage constant 1+i and 1-i, is used for providing the constant of being taken advantage of to the 3rd multiplier and the 4th multiplier respectively.

Fig. 4 shows the mapping principle of mapper of the present invention, and promptly first mapper and second mapper are carried out following mapping processing:

Be input as a=0,1,2,3, be output as i ^a,

Wherein a is the code element in four mutually perfect sequences or the displacement equivalent sequence,

First mapper is finished respectively the code element of displacement equivalent sequence and the conversion of the code element of four mutually perfect sequences with second mapper, wherein, code element " 0 " is mapped as " 1 ", code element " 1 " is mapped as " i ", code element " 2 " mapping " 1 ", code element " 3 " is mapped as " i ".

Fig. 3 has shown the generation method of accurate perfect cycle 16QAM sequence of the present invention, comprising:

Select one four mutually perfect sequence;

Described four mutually perfect sequences are carried out cyclic shift handle, obtain the displacement equivalent sequence;

Described displacement equivalent sequence is shone upon processing, obtain first sequence;

Described four mutually perfect sequences are shone upon processing, obtain second sequence;

Respectively described first sequence and described second sequence are carried out the arithmetic processing, obtain the 3rd sequence and the 4th sequence;

Described the 3rd sequence and the 4th sequence are carried out interleaving treatment, obtain accurate perfect cycle 16QAM sequence.

The mapping relations that above-mentioned mapping is handled are: be input as a=0, and 1,2,3, be output as i ^a, wherein a is the code element in four mutually perfect sequences or the displacement equivalent sequence,

First sequence and second sequence are carried out arithmetic to be handled and comprises: described first sequence and described second sequence are taken advantage of two respectively; First sequence of taking advantage of two is carried out multiply by 1+i after addition is handled with second sequence of not taking advantage of two, obtain the 3rd sequence; After taking advantage of two first sequence and second sequence of taking advantage of two to subtract each other processing, not multiply by 1-i, obtain the 4th sequence.

Select one four mutually perfect sequence to comprise: 16QAM sequence length 2N is set; From four mutually perfect sequence libraries, select its sequence length to equal the four mutually perfect sequences of N, wherein N is the positive integer more than or equal to 2.

Four mutually perfect sequences are carried out the cyclic shift processing to be comprised: displacement τ is set; Described four mutually perfect sequences are carried out cyclic shift τ position handle, wherein-N+1≤τ≤N-1 and τ ≠ 0.

In sum, the core of the generation of accurate perfect cycle 16QAM sequence of the present invention is, by four mutually perfect sequences and cyclic shift equivalent sequence thereof are shone upon, arithmetic and interweave and obtain accurate perfect cycle 16QAM sequence.

The characteristics of accurate perfect cycle 16QAM sequence of the present invention are: the cycle all is 2N, its cycle auto-correlation is perfectly accurate, non-zero auto-correlation secondary lobe occurs that the position can pre-determine and changes within the specific limits, and the non-zero side lobe levels is a pure imaginary number, and the auto-correlation real part has the impulse characteristic.

As everyone knows, the method that has many generation four mutually perfect sequences, for example, Chu method (D.Chu.Polyphasecodes with good periodic correlation properties, IEEE Trans.On Inf.Theory, vol.18, No.4,1972, pp.531-532), Frank method (R.Frank.Phase shift pulse codes withgood periodic correlation properties, IRE Trans.on Inf.Theory, vol.IT-8,1962, pp.381-382) with Zeng method (F.X.Zeng.New perfect polyphase sequences and mutuallyorthogonal ZCZ polyphase sequence sets.IEICE Trans Fundamentals, vol.E92-A, No.7, July 2009, pp.1731-1736).To any one four mutually perfect sequence, the inventive method produces an accurate perfect cycle 16QAM sequence.Therefore, can draw to draw a conclusion.

(1) required for the present invention four mutually perfect sequences have abundant source, and the length of the accurate perfect cycle 16QAM sequence of generation is the twice of selected four mutually perfect sequence lengths;

(2) quantity of the accurate perfect cycle 16QAM sequence of the inventive method generation is identical with the quantity of the four mutually perfect sequences of selecting for use.

Prove that below the cycle 16QAM sequence that the present invention obtains is perfectly accurate.

If v=(v (0), v (1), v (2) ..., v (N-1)) and be that the length of selecting is the four mutually perfect sequences of N, (0＜τ＜N-1) (consider autocorrelative symmetry, only consider that the positive displacement amount is enough) obtains sequence to selected displacement τ vShift sequence L ^τ v=(v (τ), v (τ+1), v (τ+2) ..., v (N-1), v (0), v (1) ..., v (τ-1)).

Press the mapping ruler of Fig. 4, promptly

0→1

1→i

2→-1

3→-i

So, when mapper was input as a (a=0,1,2,3), mapper output can be expressed as with relationship

i ^a (4)

So, multiplier 4 output sequences of Fig. 2 are

b＝(b(0)，b(1)，…，b(N-1))

(5)

b(t)＝(1-i)(i ^v(t+τ)-2i ^v(t))?(0≤t≤N-1)

Multiplier 3 output sequences of Fig. 2 are

a＝(a(0)，a(1)，…，a(N-1))

(6)

a(t)＝(1+i)(i ^v(t)+2i ^v(t+τ))(0≤t≤N-1)

After the process interleaver interweaves, so, can generate the 16QAM sequence

d＝{d(k)|0≤k≤2N-1}＝(a(0)，b(0)，a(1)，b(1)，…，a(t)，b(t)，…，a(N-1)，b(N-1))(0≤t≤N-1)

(7)

Perhaps

d＝{d(k)|0≤k≤2N-1}＝(b(0)，a(0)，b(1)，a(1)，…，b(t)，a(t)，…，b(N-1)，a(N-1))(0≤t≤N-1)

(8)

Proof (7) or (8) is perfectly accurate below.With formula (7) is example, considers in two kinds of situation.

(1) as u=2r (during 0≤r≤N-1)

The cycle auto-correlation of 16QAM sequence is:

Wherein, having used quadriphase sequence v in the formula (9) is the characteristic of perfect sequence, promptly

$R_{v,v}\left(u\right)=\left\{\begin{array}{cc}N& u=0\\ 0& u\≠0\end{array}\right.\left(\right|u|\≤N-1)---\left(10\right)$

(2) as u=2r+1 (during 0≤r≤N-1)

The auto-correlation of 16QAM sequence is:

Formula (9) and formula (11) show the non-zero auto-correlation secondary lobe of 16QAM sequence (7) or (8) or are four or are two pure imaginary number values, belong to accurate perfect sequence, especially, when displacement τ=N/2, non-zero auto-correlation secondary lobe only has 2 pure imaginary numbers in u=N ± 1, be respectively-6Ni and 6Ni.Simultaneously, show that also the auto-correlation real part has the impulse characteristic.

As in an example, establish N=16, generation length is 32 accurate perfect cycle 16QAM sequence.Separate: get length and be 16 four mutually perfect sequences

v＝(0?0?0?0?1?0?3?2?2?0?2?0?3?0?1?2)

According to Fig. 1, the accurate perfect cycle 16QAM sequence of generation is

$\underset{\‾}{d}=(\left(\begin{array}{c}-1\\ 3\end{array}\right),\left(\begin{array}{c}-1\\ 3\end{array}\right),\left(\begin{array}{c}-1\\ -1\end{array}\right),\left(\begin{array}{c}-3\\ 3\end{array}\right),\left(\begin{array}{c}3\\ 3\end{array}\right),\left(\begin{array}{c}-1\\ 1\end{array}\right),\left(\begin{array}{c}3\\ 3\end{array}\right),\left(\begin{array}{c}-1\\ 1\end{array}\right),\left(\begin{array}{c}1\\ 3\end{array}\right),\left(\begin{array}{c}-1\\ -3\end{array}\right),\left(\begin{array}{c}3\\ 3\end{array}\right),\left(\begin{array}{c}-1\\ 1\end{array}\right),\left(\begin{array}{c}-1\\ 1\end{array}\right),\left(\begin{array}{c}3\\ 3\end{array}\right),\left(\begin{array}{c}1\\ 1\end{array}\right),\left(\begin{array}{c}3\\ -3\end{array}\right),$ (12)

$\left(\begin{array}{c}1\\ -3\end{array}\right),\left(\begin{array}{c}1\\ -3\end{array}\right),\left(\begin{array}{c}-1\\ -1\end{array}\right),\left(\begin{array}{c}-3\\ 3\end{array}\right),\left(\begin{array}{c}-3\\ -3\end{array}\right),\left(\begin{array}{c}1\\ -1\end{array}\right),\left(\begin{array}{c}3\\ 3\end{array}\right),\left(\begin{array}{c}1\\ -1\end{array}\right),\left(\begin{array}{c}-1\\ -3\end{array}\right),\left(\begin{array}{c}1\\ 3\end{array}\right),\left(\begin{array}{c}3\\ 3\end{array}\right),\left(\begin{array}{c}-1\\ 1\end{array}\right),\left(\begin{array}{c}1\\ -1\end{array}\right),\left(\begin{array}{c}-3\\ -3\end{array}\right),\left(\begin{array}{c}1\\ 1\end{array}\right),\left(\begin{array}{c}3\\ -3\end{array}\right))$

Wherein,

Some a+bi in the expression 16QAM constellation.

Get displacement τ=6, so, by formula (11), accurate perfect cycle 16QAM sequence will be respectively on displacement is 11,13,19 and 21 position, occur pure imaginary number-32i ,-128i, 128i and 32i.Computer as calculated, the auto-correlation of accurate perfect cycle 16QAM sequence (12) is

R _d，d(τ，0:31)＝(320，0，0，0，0，0，0，0，0，0，0，-32i，0，-128i，0，0，0，0，0，128i，0，32i，0，0，0，0，0，0，0，0，0，0)

Fig. 5 has provided the mould figure of the periodic auto-correlation function of accurate perfect cycle 16QAM sequence in the above-mentioned example.

Fig. 6 has provided the real part figure of the periodic auto-correlation function of accurate perfect cycle 16QAM sequence in the above-mentioned example.

Although above the present invention is had been described in detail, the invention is not restricted to this, those skilled in the art of the present technique can carry out various modifications according to principle of the present invention.Therefore, all modifications of doing according to the principle of the invention all should be understood to fall into protection scope of the present invention.

Claims (10)

1. the generation method of an accurate perfect cycle 16QAM sequence comprises:

Select one four mutually perfect sequence;

Described four mutually perfect sequences are carried out cyclic shift handle, obtain the displacement equivalent sequence;

Described displacement equivalent sequence is shone upon processing, obtain first sequence;

Described four mutually perfect sequences are shone upon processing, obtain second sequence;

Respectively described first sequence and described second sequence are carried out the arithmetic processing, obtain the 3rd sequence and the 4th sequence;

Described the 3rd sequence and the 4th sequence are carried out interleaving treatment, obtain accurate perfect cycle 16QAM sequence.

2. method according to claim 1, the mapping relations that wherein said mapping is handled are:

Be input as a=0,1,2,3, be output as i ^a,

Wherein a is the code element in four mutually perfect sequences or the displacement equivalent sequence,

3. method according to claim 1 and 2, wherein, described first sequence and described second sequence are carried out arithmetic handle and comprise:

Described first sequence and described second sequence are taken advantage of two respectively;

First sequence of taking advantage of two is carried out multiply by 1+i after addition is handled with second sequence of not taking advantage of two, obtain the 3rd sequence;

After taking advantage of two first sequence and second sequence of taking advantage of two to subtract each other processing, not multiply by 1-i, obtain the 4th sequence.

4. method according to claim 3, wherein, one four mutually perfect sequence of described selection comprises:

16QAM sequence length 2N is set;

From four mutually perfect sequence libraries, select its sequence length to equal the four mutually perfect sequences of N, wherein N is the positive integer more than or equal to 2.

5. method according to claim 3, wherein, described four mutually perfect sequences are carried out the cyclic shift processing comprise:

Displacement τ is set;

Described four mutually perfect sequences are carried out cyclic shift τ position handle, wherein-N+1≤τ≤N-1 and τ ≠ 0.

6. the generating apparatus of an accurate perfect cycle 16QAM sequence comprises:

Four mutually perfect sequence selection unit are used to select one four mutually perfect sequence;

Circulating register carries out cyclic shift to described four mutually perfect sequences and handles, and obtains the displacement equivalent sequence;

First mapper shines upon processing to described displacement equivalent sequence, obtains first sequence;

Second mapper shines upon processing to described four mutually perfect sequences, obtains second sequence;

The arithmetic processing unit carries out the arithmetic processing to described first sequence and described second sequence respectively, obtains the 3rd sequence and the 4th sequence;

Interleaver carries out interleaving treatment with described the 3rd sequence and the 4th sequence, obtains accurate perfect cycle 16QAM sequence.

7. device according to claim 6, wherein said first mapper and second mapper are carried out following mapping and are handled:

Be input as a=0,1,2,3, be output as i ^a,

Wherein a is the code element in four mutually perfect sequences or the displacement equivalent sequence,

8. according to claim 6 or 7 described devices, wherein, described arithmetic processing unit comprises:

First multiplier takes advantage of two with described first sequence;

Second multiplier takes advantage of two with described second sequence;

First adder carries out addition to first sequence of taking advantage of two with second sequence of not taking advantage of two and handles;

Second adder subtracts each other processing to first sequence of not taking advantage of two with second sequence of taking advantage of two;

The 3rd multiplier taking advantage of two first sequence and not taking advantage of two the second addition of series result to multiply by 1+i, obtains the 3rd sequence;

The 4th multiplier not taking advantage of two first sequence and the result that subtracts each other who takes advantage of two second sequence to multiply by 1-i, obtains the 4th sequence.

9. device according to claim 6 also comprises, four mutually perfect sequence libraries, the four mutually perfect sequences that are used to preserve different length.

10. device according to claim 9 comprises that also 16QAM sequence length and displacement are provided with the unit, are used for;

16QAM sequence length 2N is set, so that four mutually perfect sequence selection unit select its sequence length to equal one the four mutually perfect sequence of N from described four mutually perfect sequence libraries, wherein N is the positive integer more than or equal to 2;

Displacement τ is set, handles so that circulating register carries out cyclic shift τ position to described four mutually perfect sequences, wherein-N+1≤τ≤N-1 and τ ≠ 0.

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