CN1555624A - A full-rate TURBO space-time encoding method and device - Google Patents

Abstract

The present invention provides a full-rate TURBO time-space encoding method and device, which includes: performing TURBO time-space encoding and signal interleaving on the transmitted signal at the transmitting end to form a mixed signal of encoded information and interleaved encoded information; The mixed signal is decoded, and the side information of the corresponding signal needs to be recovered from the received mixed signal during decoding. The present invention has the best performance in the existing space-time coding technology, especially at the receiving end, and can achieve high coding gain and diversity gain at the same time.

Description

A full-rate TURBO space-time coding method and device Technical field

The present invention relates to the technical field of telecommunication, in particular to a full-rate TURBO space-time encoding method and device.

Background technique

It is well known that in a fading channel, the fading of the signal will seriously deteriorate the performance of the system. The most effective means to overcome fading is to use "diversity". Space-time coding technology (as described in [1] to [3]) can obtain diversity gain and overcome the influence of fading.

Recently, the combination of spatio-temporal coding and FEC has attracted people's attention, and the effective combination of the two can make the system obtain the diversity gain and the coding gain at the same time.

In the original concatenated space-time coding (as described in literature [4], [5]), the outer code is a standard TURBO code, and the inner code is a space-time block code, which constitutes a serial or parallel concatenated space-time TURBO code.

In addition, a full-rate coding scheme is proposed in literature [6], [8], that is, the diversity gain is obtained by alternately transmitting the original information and the interleaved information between the two antennas. Large coding gain, but because only part of the signal is sent, no full diversity gain is obtained.

Another full-rate and full-diversity space-time TURBO coding scheme is given in [7]. This scheme achieves full-rate and full-diversity by alternately (Scramble) inputting information bits. The main defect of this scheme is that the anti-burst is poor.

Contents of the invention

The object of the present invention is to provide a full-rate TURBO space-time coding method and device to solve the defects and deficiencies in the prior art. The present invention can improve the performance of the system very well, and can obtain a large coding gain and diversity gain under the condition of reaching the full rate. The present invention has the best performance in the existing space-time coding technology, especially at the receiving end , can achieve high coding gain and diversity gain at the same time. The technical solution of the present invention is: The present invention provides a full-rate TURBO space-time encoding method, which includes: performing TURBO space-time encoding and signal interleaving on the transmitted signal at the transmitting end to form encoded information and interleaved encoding Mixed signals of information;

The received mixed signal is decoded at the receiving end, and the side information of the corresponding signal needs to be recovered from the received mixed signal during decoding.

The TURBO space-time encoding and signal interleaving of the transmitted signal at the transmitting end includes: the transmitting end can perform serial concatenation TURBO space-time encoding on the transmitting signal, wherein:

Can represent the transformation matrix from f ^to ); " can represent the input bit sequence of TURBO space-time coding, > can represent the output bit sequence of TURBO space-time coding;

When i, j, k = 1, 2, the steps of serially concatenated TURBO space-time coding are:

and 7 ⁽²⁾ are transformed into w and ⁽¹²⁾ , and ¹² ) is interleaved and the output bit stream is (O ⁽¹¹⁾ , O ⁽¹²⁾ ) ;

V ^{n) . ¹²⁾ The output bit stream after interleaving and TURBO space-time coding is (d ⁽²¹⁾ ,0 ⁽²²⁾ );

7 ⁽²⁾ transformed into ²¹⁾ and ^ ²²⁾ by TURBO space-time coding, ²¹⁾ and ²² ) output bit stream after interleaving is (d ^{(31) (32)} );

After f ⁽²¹⁾ , ²²⁾ are interleaved and TURBO space-time coded, the output bit stream is (d ⁽⁴¹⁾ , d ⁽⁴²⁾ ). The said TURBO time-space encoding and signal interleaving of the transmitted signal at the transmitting end includes: The transmitting end can perform parallel concatenated TURBO time-space encoding on the transmitting signal, wherein:

can be used to represent the transformation matrix from to >; can represent the input bit sequence of TURBO space-time coding, and can represent the output bit sequence of TURBO space-time coding;

When i, j, k = 1, 2, the steps of parallel cascading TURBO space-time encoding are:

The output bit stream of f( ² ) is ⁽¹¹ ),(5( ¹² ));

/ ^(,) , ⁽²⁾ the output bit stream after TURBO space-time coding is ²¹⁾ , d ⁽²²⁾ );

, /( ² ) the output bit stream after interleaving is (d( ³¹ ), d( ³² ));

, the output bit stream after interleaving and TURBO space-time coding is (d ⁽⁴¹ ) ( ⁴²⁾ ).

The TURBO time-space encoding and signal interleaving of the transmitted signal at the transmitting end includes: the transmitting end can perform TURBO space-time encoding for serial concatenation modulation and expansion of the transmitting signal, wherein:

7 ^) can be used to represent the transformation matrix from > to ^ »; it can represent the input bit sequence of TURBO space-time coding, and can represent the output bit sequence of TURBO space-time coding;

When = 1, 2, the steps of TURBO space-time coding of serial concatenated modulation extension are: ⁽¹⁾ , ⁽²⁾ transformed into, f ⁽¹²⁾ , ⁽ⁿ⁾ > ¹²⁾ and the output bit stream after interleaving is

(„);

F ⁽¹¹⁾ , ¹²⁾ the output bit stream after interleaving and TURBO space-time coding is (<5 ⁽²¹⁾ ,d ⁽²²⁾ ); (", ( ² ) are transformed into f( ²¹ ), V ⁽²²⁾ , f( ²¹ ), ²² ) the output bit stream after interleaving is (d ⁽³¹⁾ ,d ⁽³²⁾ );

VK ²² ) The output bit stream after interleaving and TURBO space-time encoding is (<5( ⁴¹ d ⁽⁴²⁾ ); the output bit stream is mapped to the QPSK signal and the symbols are, S ₁₂ , S ₂₁ and ¾ ₂ ;

S _u , 5 ₁₂ , and the symbols after the modulation and expansion into 16QAM signals through the transformation function /(c, and

S, and can be transmitted on two antennas after channel interleaving.

The TURBO time-space coding and signal interleaving of the transmitted signal at the transmitting end includes: the transmitting end can perform TURBO space-time coding for parallel concatenated modulation and expansion of the transmitted signal, wherein:

W can be used to represent the transformation matrix from " to >; it can represent the input bit sequence of TURBO space-time coding, and ) can represent the output bit sequence of TURBO space-time coding;

When i, j, k = 1, 2, the steps of TURBO space-time coding for parallel concatenated modulation extension are:

7 ⁽¹⁾ , ) output bit stream is (<5 ⁽¹¹ ), ό( ¹² ));

, ⁽² ) the output bit stream after TURBO space-time coding is ⁽²¹⁾ , d( ²²⁾ );

, ⁽²⁾ the bit stream output after interleaving is ((5 ^{(31) (32)} );

, ⁽²⁾ The output bit stream after interleaving and TURBO space-time encoding is (d ⁽⁴¹ ).

The symbols after the output bit stream is mapped to the QPSK signal are, S ₁₂ , s ₂₁ and s ₂₂ \

S _n , S _n , 4 and ₂ will be expanded to 16QAM signals by the transformation function / ( ) and the symbols after modulation are and ¾ , that is, ¾ = f(S _u , S _u ) and = f(S _2V S ₂₂ );

S, and can be transmitted on two antennas after channel interleaving.

The decoding of the received mixed signal at the receiving end includes: LOG-MAP decoding that can extend the received mixed signal at the receiving end.

The decoding of the received mixed signal at the receiving end includes:

Extended 2-dimensional LOG-MAP decoding can be performed on the received mixed signal at the receiving end, where: The form of the received signal is: Ri = h _u S ₁ +h ₂₁ -S ₂ = 2h _u -S _n +2h ₂₁ -S ₂₁ +h _n -S _n +h ₂₁ -S ₂₂

R ₂ = h _n -S _x +h ₂₂ -S ₂ = 2h _n -S _u +2h ₂₂ -S _2l +h -S _n +h ₂₂ -S ₂₂ .

The received signal at time k is

， A + hi2， k^S l，k + A 22, 22, A:

k ' r\k ~ k ^s n, k +2k _{21 k} s _{2l k} +h _{u fc} s _{l2 k} + h ₂ , _k s ₂₂ ， _k — k ^s u, k +2h _{2l k} p _{ll k} +h _u ， _k s _{2 k} + h ₂ ， _k p _l2 ， _k , r2k ⁼

, A + hi2, k ^S l, k + A 22, 22, A:

k '

In the formula, Α,, _/£ = ¾, _Λ . is the value of the check sequence of the source ^ at time k, and similarly Α ₂ Λ. = ½, _Α is the value of the check sequence of the interleaved sequence at time k value;

Each received signal is actually the sum of 4 parts, including the information sequence, the interleaved information sequence, the check sequence of the information sequence, and the check sequence of the interleaved information sequence, after they respectively pass through different fading channels synthesized into the received signal.

The decoding of the received mixed signal at the receiving end includes:

Filtering, radio frequency and intermediate frequency demodulation, and despreading can be performed on the received mixed signal at the receiving end, and the APP of the processed baseband signal is calculated; the decoding includes 4 loops, and iterative decoding is performed on these 4 loops; in:

The joint probability density needs to meet the following conditions:

_t ,σ _k ² ,u j)p{u_lk = u(i))p(u_2k = u(j)) f

_t ,σ _k ² ,uj)p{u _lk = u(i))p(u _2k = u(j))

P(y _k I σ,',η,,σ^ ,η^ = (πΝ ₀ Υ ^Μ exp(--^- || y _k ~ E7H _A S, ||"; the posterior probability must meet the following conditions:

("u = u{i),u _2k = u(j) I 7)

Information bits need to meet the following conditions:

P( _u = u(i) I 7)

The interleaved information bits need to meet the following conditions: P(u _2k = u(j) I 7)

Under multipath conditions:

one ²

P(y _k I a _k ^l ,ua _k ² ,Uj ) = {ττΝ ₀ Υ ^Μ exp(- || )

Side information needs to meet the following conditions:

V (FI u(i)) = P(u _u = "(0 IY)-P(u _u = "())

L ^e {YI u{j)) = P{u _2k = u{j) IY)-P{u _lk = u(j)) - During iterative decoding, the sum of every 3 side information will be used as another 1 The prior information of road information, namely: P(u = u _x (i)) = CI ^) + ₃ ("() I y ₂ ) + L^(u(j) I y ₂ )

Similarly, each path of prior information in the other three paths of information bits is equal to the sum of the other three paths of side information. The decoding of the received mixed signal at the receiving end includes:

Filtering, radio frequency and intermediate frequency demodulation, and despreading can be performed on the received mixed signal at the receiving end, and the APP of the processed baseband signal is calculated; the decoding includes 2 loops, and iterative decoding is performed on these 2 loops; Among them: The joint probability density needs to meet the following conditions:

u(i))p(u _u = "(_/)) 2

);

The posterior probability needs to meet the following conditions:

P("u- = uf), u _u = u(j) IY)

Information bits need to meet the following conditions:

P( _lk = u(i) IY) σ _k ^l σ _k ²

The information bits after interleaving need to meet the following conditions:

P( _2k = (j) IY)

"i* σ _t ¹ σ ₄ ²

Under multipath conditions: P(y _k I ,ua _k ² ,Uj ) = (πΝ ₀ )~ ^Μ exp(- || )

Side information needs to meet the following conditions:

L ^e (YI "(0) = P(u _lk = "(!·) IY)-P(u _u = u(i))

L ^e {YI u{j)) = P(u _2k = u(j) IY)-P(u _2k = u(j))

There is one side information output during iterative decoding, and they are respectively used as prior information for the next iterative decoding.

The TURBO space-time coding can be recursive space-time convolutional coding.

The present invention also provides a full-rate TURBO space-time encoding device, including a transmitting device and a receiving device, characterized in that: the transmitting device includes at least a TURBO space-time encoder and a signal interleaver, the TURBO space-time encoder encodes the transmitted signal, and the signal is interleaved The device interleaves the transmitted signal to form a mixed signal of encoded information and interleaved encoded information;

The receiving device decodes the received mixed signal, and needs to recover the side information of the corresponding signal from the received mixed signal during decoding.

The transmitting device at least includes a TURBO space-time encoder and a signal interleaver means: The TURBO space-time encoder and the signal interleaver can form a serial cascaded TURBO space-time encoding device.

The transmitting device at least includes a TURBO space-time encoder and a signal interleaver means that: the TURBO space-time encoder and the signal interleaver can form a parallel cascaded TURBO space-time encoding device.

The transmitting device includes: a serial concatenation TURBO space-time coding device, a modulation and expansion device, and a channel interleaver composed of a TURBO space-time encoder and a source interleaver; wherein:

The transmitted signal is transmitted from the corresponding antenna after being encoded by the TURBO space-time encoding device, modulated and expanded by the modulation and expansion device, and interleaved by the channel interleaver through the serial concatenation of the TURBO space-time encoder and the source interleaver.

The transmitting device includes: a parallel cascaded TURBO space-time coding device, a modulation and T spreading device, and a channel interleaver composed of a TURBO space-time encoder and a source interleaver; wherein:

The transmitted signal is encoded by the parallel cascaded TURBO space-time encoding device formed by the TURBO space-time encoder and the source interleaver, modulated and expanded by the modulation and expansion device, and interleaved by the channel interleaver, and then transmitted from the corresponding antenna.

The receiving device at least includes: an extended LOG-MAP decoding device, the extended LOG- The MAP decoding device can decode the received mixed signal.

The extended LOG-MAP decoding device can be an extended 2-dimensional LOG-MAP decoding device, which includes a matched filter, an APP calculator, a deinterleaver, an adder, and an interleaver;

When decoding: Iterative decoding is performed on 4 loops.

The extended LOG-MAP decoding device may be an extended 2-dimensional LOG-MAP decoding device, which includes a matched filter, an APP calculator, a deinterleaver, an adder, and an interleaver;

When decoding: Iterative decoding is performed on 1 loop.

The beneficial effects of the present invention are: the present invention can well improve the performance of the system, and can obtain a large coding gain and diversity gain under the condition of reaching the full rate, and the present invention has the best performance in the existing space-time coding technology Performance, especially at the receiving end, can achieve high coding gain and diversity gain at the same time.

Description of drawings

Fig. 1 is a schematic structural diagram of the 2/8 rate serial concatenated TURBO space-time coding in the specific implementation of the method of the present invention;

Fig. 2 is a schematic structural diagram of 2/8 rate parallel concatenated TURBO space-time coding in the specific implementation of the method of the present invention;

FIG. 3 is a QPSK signal constellation diagram of the method of the present invention;

FIG. 4 is a 16QAM signal constellation diagram of the method of the present invention;

Fig. 5 is a structural block diagram of the TURBO space-time encoding of the serial concatenated modulation expansion of the device of the present invention in a specific implementation;

FIG. 6 is a block diagram of the TURBO space-time coding structure of parallel concatenated modulation expansion in the specific implementation of the device of the present invention;

FIG. 7 is a schematic diagram of channel fading of the two-transmit and two-receive system of the present invention;

FIG. 8 is a schematic structural diagram of the extended 2-dimensional LGO-MAP decoding algorithm 1 of the modulated extended space-time TURBO code in the specific implementation of the device of the present invention;

FIG. 9 is a schematic structural diagram of an extended 2-dimensional LOG-MAP decoding algorithm 2 of modulated and extended space-time TURBO coding in a specific implementation of the device of the present invention;

FIG. 10 is a graph comparing the BER performance of the full-rate extended space-time coding of the present invention with the BER performance of other coding schemes in a fading channel. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a full-rate TURBO space-time encoding method, which includes: performing TURBO space-time encoding and signal interleaving on the transmitted signal at the transmitting end to form a mixed signal of encoded information and interleaved encoded information;

The received mixed signal is decoded at the receiving end, and the side information of the corresponding signal needs to be recovered from the received mixed signal during decoding.

Taking the structural diagram of 2/8 rate serial concatenated TURBO space-time coding as shown in Figure 1 as an example, this coding scheme is described in detail. It has been pointed out in [8] that the performance of recursive space-time convolutional coding is better than that of non-recursive coding, so the space-time encoders in Figure 1 and Figure 2 generally use recursive space-time convolutional coders.

Let Ty{k) denote the transformation matrix from to ( i,j,k = \,2 ).

where ⁽⁴⁾ , = 1,2 and fi, j = 1,2 are the input and output bit sequences of the recursive convolutional encoder. The final 4-column bit stream output by the concatenated encoder is ((^" ), (0 ⁽³¹⁾ ,ό ⁽³²⁾ ), (0 ⁽²¹⁾ ,δ ⁽²²⁾ ) and (<5( ⁴¹ ),d ( ⁴² )), the symbols mapped to QPSK signals are S ₁₂ , S ₂₁ and ₂ .

s _n , s ₁₂ , ¾ and ₂ will be assembled into two symbols by the following transformation function /c,

^ and ^ , namely

(1)

S ₂ = f(S _2l) S ₂₂ ) (2)

^ and ¾ will finally be transmitted on two antennas after channel interleaving. .

The following only discusses the case when /(X, is a linear function of

In the formula, _Pf is called a power normalization factor, which is used to ensure that the signal power remains unchanged before and after conversion. «, is called the pooling coefficient, α…, Α, is called the normalized pooling coefficient.

Calculated, (4)

It can be constant, or it can be different due to different signal points in the constellation diagram, so that phase rotation can be generated. In the following, we only discuss the case where α, is a constant.

At this time, it can be expressed as

where = [β] is called the coefficient matrix _t. For example, α = ^,β = then f _(x , _y)

At this time, the QPSK signal, ¾, S _2l and ₂ will be transformed into a rectangular 16QAM signal by /x

2S, +S. 22

The signal constellation diagrams of QPSK symbols , , s _2l and ₂ and the transformed 16QAM signal constellation diagrams are shown in Fig. 3 and Fig. 4 .

Therefore, this scheme is actually a modulation-extended space-time coding scheme, which can use the expanded modulation factor in exchange for diversity or coding gain.

As shown in Figure 2, the parallel concatenated modulation spread space-time coding is composed of a parallel concatenated convolutional encoder, a source symbol interleaver, a signal transform and mapper, and a channel interleave.

The basic idea of space-time-frequency dimension design and a serial-parallel cascading coding scheme designed using this idea are discussed above. Reasonable use of space-time-frequency dimensions can meet different needs, and achieve diversity gain, coding gain and increase capacity to the greatest extent.

For the space-time-frequency TURBO coding of modulation expansion, since each received signal actually contains two unknown signals and corresponding checksums at the same time, the traditional LOG-MAP algorithm cannot complete the decoding of this coding structure system. This section will promote the traditional LOG-MAP algorithm and obtain an extended LOG-LOG decoding method, which can effectively solve this problem, so this section first gives the MAP decoding method of the above-mentioned extended space-time frequency Turbo coding . When the encoding method described above is used, the form of the received signal is:

?] = h _n . S _r + h ₂₁ S ₂ = 2h S _n + 2 "h ^Γ _2l S ⁼ ₂₁ + h _u . S ₁₂ + h _2l . S ₂ (7)

(8) ^R 2 = i · ^S l + i · ^S 2 -

(8)

The received signal at time k is

+ 2h₂、_ks ,_k + h_u,_ks_n,_k + _{2l k}s_{22 k} — 2h_u,_ks_u,_k + 2h_2ltkp_nk + h_nks_nJi + h _kp_ilk (9)

+ 2h ₂ 、 _k s , _k + h _u , _k s _n , _k + _{2l k} s _{22 k} — 2h _u , _k s _u , _k + 2h _2ltk p _nk + h _nk s _nJi + h _k p _ilk (9)

r2k ⁼ 2h _l2 , _k s _u , _k + 2h _22k s _2lk + h _uk s _nk + h _22k s _22k

(10) In the formula, ^=¾ ₄ is the value of the check sequence of the source at time k, and similarly P _1U ^^ is the value of the check sequence of the interleaved sequence at time k.

It can be seen from (9) and (10) that each received signal is actually a sum of four parts, including the information sequence, the interleaved information sequence, the check sequence of the information sequence, and the check sequence of the interleaved information sequence. After passing through different fading channels, they are synthesized into received signals.

(9), ₄ in (10), as shown in FIG. 7, represents the channel fading between the first transmitting antenna and the first transmitting antenna,

Fig. 8 shows a decoding block diagram of 2-transmit-2-receive, parallel concatenated modulation and extended space-time coding. The two received signals first pass through two received matched filters to complete the functions of radio frequency and intermediate frequency demodulation and despreading. The processed baseband signal is fed into two APP (posterior probability) calculators. It can be seen from FIG. 8 that this decoding includes 4 loops, and iterative decoding is performed on these loops. A more detailed decoding algorithm is given below.

In order to use the MAP algorithm, it can be assumed that is independent, in order to be consistent with the derivation of the traditional LOG-MAP decoding idea, let:

^S U,k " ^U , ^S V2,k ~ ^U 2k (11)

Now require:

P(¾

(12)

To adopt the LOG-MAP decoding method, define:

= ^p i ^u ik

a _k (σ^ ,σ, ² ) = P(a _k ^l ,σ^,Υ') (14)

, 从状态 σ_¾'到 + ， 并且输入为 u{j) , 从状态 ²到 ₄₊₁ ²， 输出为 时的联合概率密度。 (15)

, from state σ _¾ ' to + , and the input is u{j) , from state ² to ₄₊₁ ² , the joint probability density when the output is .

After simplification, we can get,

ΥΪ ¹ > ^σ Μ ^σ Μ ,y _k ) = p(y _k I ^{σ w} « > ^σ ¾ ² ' ^u j )P( ^u = ^u f))pu _lk = )) (17)

Independence is used in the above formula. where p, y _k I || ² ) (18)

2s, _u . +5.

In the above formula, s _t = 1 - ' °\2k , if _Λ = _ι , H _k = (h _k A ₂₁₄ ), and if; _t = r ₂ ,

² Puk +Pm)

In the formula, M represents the number of receiving antennas.

The above formula is derived assuming that there is no parallel path, and the algorithm when there is parallel path is the same as the previous processing method.

Similarly, the iterative formula of can be obtained,

β/ ( ', σ _/£ ² ) σ _Μ ² ,y _k ) (20)

Using the above formula, the posterior probability expression can be obtained,

P(u _k = u(i),u _2k = u(j) IY)

( ²¹ )

so as to obtain

P(u, _k =u(i)\Y)

( ²²⁾ and

P( _2k = u(j) IY)

^{= Λ} ΣΣΣ%( ^σ ^ ² (σ ^ ₊ /,σ , _σ , ₊ Λ)Α- _{+1 +} ^ ₊₁ ² ) ⁽²³⁾ When calculating h, as long as the probability of the above two formulas for all input sums is guaranteed is 1, the corresponding h can be obtained.

Under multipath conditions, the formula for calculating ; ) can be modified as: p{y _k I y _ki - _s H _kl s _kl \\ ) (24)

In the above formula, the subscript / represents the /th path signal and fading, L is the number of multipaths, M is the number of receiving antennas, and ^ represents the channel matrix of the /th path at time 1.

When there are parallel paths, all calculation processes are the same, only the parallel paths need to be treated as ordinary paths, and when calculating α, Α, it is also necessary to sum the parallel paths. So α, Α should correspond to each path. For systems with parallel paths, it is not recommended to use the method described above. In [10], Bruce E.Wahlen gave a Pragmatic Trellis code designed for parallel paths, which can be concatenated for space-time coding system.

In this way, the full information of is obtained respectively, and the side information of is given as follows:

L ^e (YI "(0) = P(u _ik = u(i) IY)― P(u _lk = u{i)) (25)

L ^e (YI u(j)) = P{u _2k = u(j) IY) - P{ _u = u(j)) (26)

On each receiving antenna, the information bits and the side information of the interleaved information bits can be obtained separately. In this way, when there are two receiving antennas, in fact, the side information of 4 related information bits can be obtained. Therefore, if iterative Decoding can achieve a coding efficiency of 1/4 code rate.

The system block diagram of iterative decoding is shown in Figures 8 and 9:

For a two-transmit and two-receive system, for the first receiving antenna, according to the above formula, the side information of the information bit _¾ and the interleaved information bit ^ can be obtained respectively ( | _M (0) , L\{y, \u{j )) Similarly, for the first receiving antenna, according to the above formula, the side information ^(^"(o), ο^">) of the information bits ^ and the interleaved information bits can be obtained respectively. In this way, four side information about the information bits are actually obtained, which are denoted as L ^e _k ( _yi I "(0) after interleaving is L {y _x I u(i)).

Therefore, during iterative decoding, this is equivalent to the iterative decoding of multiple TURBO codes. During iterative decoding, the sum of every three side information will be used as the prior information of another channel of information. For example, as shown in Figure 8, the prior information of _Ulk in the first receiving antenna will be equal to (u(j) |^), L ^e ₃ (u(i)\y ₂ ) during iterative decoding, «)| ₂ ) and.

Namely: P(u _u = u _x (0) = (u(j) \ _yi ) + L (u(i) \y ₂ ) + L^ (u(j) \ y ₂ ) (27) Similarly, Each path of prior information in the other three paths of information bits is equal to the sum of the other three paths of side information.

The decoding algorithm 1 given above essentially performs iterative decoding on two receiving antennas. In fact, the two receiving antennas may not be used for iterative decoding, but combined when calculating the metric to obtain diversity gain, which we call decoding scheme 2. Fig. 9 shows the decoding block diagram of the decoding algorithm 2. At this time, the decoder only includes two loops, and the iterative decoding is only performed in these two channels of information.

(28) At this time, the signals of the two receiving antennas are only combined in diversity when calculating _Λ |σΛ",.,σΛ". At this time, the calculation of the metric should be the sum of the metrics of the two receiving antennas, and it will change when calculating ^ :

(28)

The conditional probability ( I ) in the above formula should ~ be exactly:

P(y _k I σΛ",.,σΛ" Λ,· - II ) ( ²⁹ )

In addition, the calculation of other probabilities is the same as that in decoding algorithm 1.

Therefore, there is only one APP calculator at this time, and only two side information outputs, which are respectively used as prior information for the next iterative decoding.

The analysis of the simulation results is given below, as shown in Figure 10, when the extended LOG-MAP decoding algorithm is used, the mapping function / ( ^^^x + ^y , _α „·. β _η =2 ·.1, the The scheme is compared with the performance of the full-rate space-time TURBO coding scheme proposed in [6], [8] and the scheme proposed by Tarokh in [2]. In the simulation, this scheme adopts 4 states, and each channel model is single-path fading Channel, channel estimation uses continuous pilot assisted channel estimation, moving speed 60km/h, internal interleaving uses 512bit random interleaver, channel interleaving uses 9800bit random interleaver, spreading gain 32, adopts continuous pilot channel estimation, The iteration is 6. In the simulation results given below, it is assumed that the total transmit power of the two transmit antennas is the same as the total transmit power of a single antenna without transmit diversity.

The present invention can improve the performance of the system very well, and can obtain a large coding gain and diversity gain under the condition of reaching the full rate. The present invention has the best performance in the existing space-time coding technology, especially at the receiving end , can simultaneously achieve high coding gain and diversity gain. The cited references of the present invention are as follows: [I] . S. M. Alamouti, " A simple transmit diversity technique for wireless [2] . V. Tarokh, H. Jafarkhani, and A. R. Calderbank, "Space time block coding for wireless communications: Performance results, " IEEE JSAC, voll.17 , pp.451-460, Mar.1999.

[3] V. Tarokh, H. Jafarkhani, and A. R. Calderbank, "Space-time block coding for wireless communications: Theory of generalized orthogonal designs," IEEE Trans. On Information Theory, vol.45, pp.1456-1467, July . 1999.

[4] G. Bauch, "Concatenation of space-time block codes and turbo TCM," IEEE International Conference on Communications (ICC'99), pp.1202-1206, June 1999.

[5] KR Narayanan, "Turbo decoding of concatenated space-time codes," 37 ^th

Annual Allerton Conference on Communication, Control and Computing, Sept, 1999.

[6] Hsuan-Jung Su and Evaggelos Geraniotis, "Space-Time Turbo Codes with Full Antenna Diversity", IEEE Tans, on Commun, vol.49, NO.1, Jan 2001.

[7] Y.Liu _? MP Fitz and 0· Y, Takeshi ta, "QPSK space-time turbo codes," IEEE International Conference on Communications (ICC'OO) , June 2000.

[8] D. Cui and AM Haimovich, "A new bandwidth efficient antenna diversity scheme using turbo codes," ^34th Annual Conference on Information Sciences and Systems (CISS'00), vol.1, pp. TA— 6.24-29, Mar. 2000, Princeton, NL

[9] Robert J. McElience, David J. C. Mackay and Jung-Fu, "Turbo Decoding as an Instance of Pearl's "Belief Propagation" Algorithm", IEEE JSAC,

Vol.16, No.2, Feb 1998.

[10] Bruce E. Wahlen and Calvin Y. Mai, "Turbo Coding Applied to Pragmatic Trellis-coded", IEEE Communication Letters, VOL.4, NO.2, Feb 2000.

[II] D, J. C. MacKay, "A free energy minimization framework for inference problems in modulo 2 arithmetic, " in Fast Software Encryption, B. Preneel, Ed.

Berlin, Germany: Springer-Verlag Lecture Notes in Computer Science, vol.1008, 1995, pp.179-195.

[12] D. J. C. MacKay and R. M. Neal, "Near Shannon limit performance of low density parity check codes, " Electron. Lett. , vol.32pp.1645-1646, Aug.1996.

[13] . E. Telatar, "Capacity of Multi-antenna Gaussian Channels", IEEE Trans.

Commun, vol.42, No.2/3/4, pp.1617-1627, November-December 1999.

[14]. C. Chuah, JM Kahn and D. Tse _? "Capacity of Multi-Antenna Array Systems in Indoor Wireless Environment", accepted for publication in Globecom, Sydney, 1998，

Claims (1)

Rights request 1. A full-rate TURBO space-time encoding method, which includes: performing TURBO space-time encoding and signal interleaving on the transmitted signal at the transmitting end to form a mixed signal of encoded information and interleaved encoded information; The received mixed signal is decoded at the receiving end, and the side information of the corresponding signal needs to be recovered from the received mixed signal during decoding. 2. The method according to claim 1, wherein said performing TURBO space-time encoding and signal interleaving on the transmitting signal at the transmitting end comprises: the transmitting end can perform serial concatenation TURBO space-time encoding on the transmitting signal, wherein: 2. (A) can be used to represent the transformation matrix from to ^ "; it can represent the input bit sequence of TURBO space-time coding, and can represent the output bit sequence of TURBO space-time coding; When = 1,2, the steps of serial concatenation TURBO space-time encoding are: / ^(,) and) are transformed into and ²⁾ , f ⁽ⁿ⁾ and ¹²⁾ are interleaved and the output bit stream is (0 ^(,1 ,0 ⁽¹²⁾ ); The output bit stream of V ^(W , ²⁾ after interleaving and TURBO space-time coding is ((5 ⁽²¹ ^ ⁽²²⁾ ); lK ⁽²⁾ is transformed into ²¹⁾ and ^{22 )} by TURBO space-time coding,. ²²⁾ The output bit stream after interleaving is (d ⁽³¹⁾ , d ⁽³²⁾ ); The output bit stream of V ^{{2l 22} ) after interleaving and TURBO space-time encoding is (d( ⁴¹⁾ ,d ⁽⁴²⁾ ). 3. The method according to claim 1, characterized in that, performing TURBO space-time coding and signal interleaving on the transmitted signal at the transmitting end comprises: the transmitting end can perform parallel concatenated TURBO space-time coding on the transmitting signal, wherein: 2) can be used to represent the transformation matrix from to ); It can represent the input bit sequence of TURBO space-time coding, and can represent the output bit sequence of TURBO space-time coding; When i, j, k = 1, 2, the steps of parallel cascading TURBO space-time coding are: ), /( ² ) the output bit stream is (d ⁽¹¹ ), d( ¹² )) ; , 7 ⁽²⁾ the output bit stream after TURBO space-time coding is (<5 ⁽²¹⁾ , 0 ⁽²²⁾ ); , ⁽²⁾ The output bit stream after interleaving is (d ⁽³¹⁾ , d ⁽³²⁾ ); , 7 ⁽²⁾ The output bit stream after interleaving and TURBO space-time coding is (<5 ^{(41) (42)} ). 4. The method according to claim 1, characterized in that, performing TURBO space-time coding and signal interleaving on the transmitted signal at the transmitting end comprises: performing TURBO space-time coding for serial concatenated modulation and expansion of the transmitting signal at the transmitting end ,in: ⁷ ) can be used to represent the transformation moment from ⁽ "to)! When ,A: = 1,2, the steps of TURBO space-time coding for serial concatenated modulation extension are: , / ⁽²⁾ transformed into "), ⁽¹²⁾ , f ⁽ⁿ⁾ , ^(,2) the output bit stream after interleaving is „ ); f ⁽ⁿ⁾ , ¹²⁾ the output bit stream after interleaving and TURBO space-time encoding is (0 ⁽²¹ ), d ⁽²²⁾ ); /( ² ) is transformed into ^ ²¹ ), V ²²⁾ , V ^{) 22} ) The output bit stream after interleaving is (<5 ⁽³¹⁾ ,d ⁽³²⁾ ); ' The output bit stream of V ^{(21 22)} after interleaving and TURBO space-time encoding is (d ^{(41) (42)} ); the output bit stream is mapped to QPSK signals and the symbols are _l2 , S _2l and S ₂₂ ; S _n , S _l2 , and ₂ will be the sum of symbols after modulation and expansion into 16QAM signals through the transformation function /(x, ie =/( ₁₁ ,4) and ₎ ¾=/( ₁ , ₂ ); s _x and can be transmitted on two antennas after channel interleaving. 5. The method according to claim 1, characterized in that, performing TURBO space-time coding and signal interleaving on the transmitting signal at the transmitting end comprises: performing TURBO space-time coding for parallel concatenated modulation and expansion of the transmitting signal at the transmitting end, in: 7. ) can be used to represent the transformation matrix from to ^ ^; can represent the input bit sequence of TURBO space-time coding, and ^ can represent the output bit sequence of TURBO space-time coding; When = 1,2, the steps of TURBO space-time coding for parallel concatenated modulation expansion are: / ^(,) , : The bit stream output by r( ² ) is (d" ¹ ),^ ¹ ); , ⁽²⁾ the bit stream output after TURBO space-time coding is (<5( ^21)(22) ); 7 ⁽¹⁾ , / ⁽²⁾ the output bit stream after interleaving is (0 ⁽³¹⁾ ,0 ⁽³²⁾ ); The output bit stream of J ⁽¹⁾ , / ⁽²⁾ after interleaving and TURBO space-time coding is (0 ⁽⁴¹⁾ ,d ⁽⁴²⁾ ). The symbols after the output bit stream is mapped to the QPSK signal are, S _n , S _2l and ¾ ₂ ; S _n , S _u , ^ and ^ will be extended to the 16QAM signal through the transformation function/modulation and the symbols are S and, namely ^ =/(U ₁₂ ) and =/( ₂₁ , ₂ ); 5. and can be transmitted on two antennas after channel interleaving. 6. The method according to claim 1, wherein said decoding the received mixed signal at the receiving end comprises: LOG-MAP decoding capable of extending the received mixed signal at the receiving end. 7. The method according to claim 2, wherein said decoding the received mixed signal at the receiving end comprises: At the receiving end, the received mixed signal can be extended to 2-dimensional LOG-MAP decoding, where: The form of the received signal is: R _l = _n -^. +h _2l -S ₂ = 2h _u -S _u +2h -S _2l +h _u -S +h ₂₁ -S ₂₂ R ₂ = h _n -S! +h ₂₁ -S ₂ = 2h ₁₂ - S _n +2h ₂₂ -S _2l +h _u -S _l2 +h ₂₂ •5' ₂₂ . The received signal at time k is T 2k

⁼ 2/i _12> } _C S _k + 22, k Pll,k ^12, k ^S 12, k + 22, k P \2, lc , In the formula, ^ = ¾ ^ is the value of the check sequence of the source at time k, and similarly Aw = ¾, _t is the value of the check sequence of the interleaved sequence at time k; Each received signal is actually the sum of 4 parts, including the information sequence, the interleaved information sequence, the check sequence of the information sequence, and the check sequence of the interleaved information sequence, which are synthesized after passing through different fading channels to receive the signal. 8. The method according to claim 3, wherein said decoding the received mixed signal at the receiving end comprises: At the receiving end, the received mixed signal can be extended to 2-dimensional LOG-MAP decoding, where: 'The form of the received signal is: R ₁ = h _n -Si +h ₂₁ -S ₂ = 2h _n -S _u +2h _2l -S ₂₁ +h _u -S _l2 + h _2l -S ₂₂ R ₂ = h _u . +h ₂₂ -S ₂ = 2h _n -S +2h ₂₂ -S _2l +h ₁₂ -S _u +h ₂₂ -S ₂₂ . The received signal at time k is ^^u,k ^s \\ +2h _{21 k} p _uk ^- _{U) k} s _c +h _{2l c} p _{l2} k} ; r2k ~

2, fc ^S , k + 22, k ^S 22, k ― 2¾ ₁₂₍ k ^S U _t k ⁺ k ' In the formula ' _Al , ₄ = _¾ , _/£ is the value of the verification sequence of the source at time k, similarly Aw = ½ is the value of the calibration sequence of the sequence after ¾ ₁ interleaving at time ^k ; Each received signal is actually a sum of four parts, including an information sequence, an interleaved information sequence, a check sequence of the information sequence, and a check sequence of the interleaved information sequence, which are synthesized after passing through different fading channels respectively to receive the signal. 9. The method according to claim 4, wherein said decoding the received mixed signal at the receiving end comprises: At the receiving end, the received mixed signal can be extended to 2-dimensional LOG-MAP decoding, where: The form of the received signal is: · Ri = h _n -S! + ^2i = 2Λ„ -S _n +2h _2l -S _2l +h _n -S _u +h _2l -S ₂₂ R ₂ = h ₁₂ •S ₁ +h ₂₂ -S ₂ = 2h _l2 -S _n +2h ₂₂ -S ₂₁ +h _l2 -S ₁₂ +h ₂₂ -S ₂₂ . The received signal at time k is

+ _k S , _k + h _{2 k} S ₂₂ , _k

r2k ~ 2Λ ₁₂₎ fc^n, k ^^22,k ^S 2\,k ⁺ ^12, A ^12, k ⁺ ^22, A ⁵ 22, A: ― 2/? _{12) k} S _{Ut k} + 2? 2 _2j hPu, k +, 2> k ^S , k + ₂₂ , _k P \ ₂ , _k , In the formula, A _W =2 _A is the value of the check sequence 2 of the source 4 at time k, similarly Aw = ¾ is the value of the check sequence of the interleaved sequence at time ^k ; Each received signal is actually the sum of 4 parts, including the information sequence, the interleaved information sequence, the check sequence of the information sequence, and the check sequence of the interleaved information sequence, which are synthesized after passing through different fading channels to receive the signal. 10. The method according to claim 5, wherein said decoding the received mixed signal at the receiving end comprises: Extended 2-dimensional LOG-MAP decoding can be performed on the received mixed signal at the receiving end, where: The format of the received signal is: i?, = h _u S _i + h ₂₁ -S 2 = 2h _u -S _n +2h ₂₁ S ₂₁ +h _ll -S ₁₂ + k ₂₁ S ₂₂ R ₂ = S ₁ +h ₂₂ - S ₂ = 2h _l2 -S _n +2h ₂₂ -S ₂₁ +h _n -S _n +h ₂₂ S ₂₁ ., The received signal at time k is

a^ ¹ _k s _k + 2h ₂₁ , _k p _u , _k -^-h _lk s _{l2 k} + h ₂ , _k p ₂ , _k , r2k ⁼ 2/¾ _12l k ^S l\,k + 2h ₂₂ ， _k S ₂ , _k ch _{l2i k} S _k + Λ ₂ 2, k ^S 22,k -

A + ₂₂ ， _k P ₂ ， _k , In the formula, Aw=2, _t is the value of the check sequence 2 of the source at time k, and similarly _Pxu =^ is the value of the check sequence of the interleaved sequence at time k; Each received signal is actually the sum of 4 parts, including the information sequence, the interleaved information sequence, the check sequence of the information sequence, and the check sequence of the interleaved information sequence, which are synthesized after passing through different fading channels to receive the signal. 11. The method according to claim 5, wherein said decoding the received mixed signal at the receiving end comprises: Filtering, radio frequency and intermediate frequency demodulation, and despreading can be performed on the received mixed signal at the receiving end, and the APP of the processed baseband signal is calculated; the decoding includes 4 loops, and iterative decoding is performed on these 4 loops; in: The joint probability density needs to meet the following conditions: rl{cr _k ^l ,a _k÷l ^l ,a _k ² ,a _{k +} ² ,y _k ) = p(y _k \ σ _k ^l ,ua _k ² ,uj)p{u _xk = u{i)) p(u _2k = "(_/ )) P(y _k I || ² ); The posterior probability needs to meet the following conditions: P{u _xk = u(i),u _2k = u(j) I 7) Information bits need to meet the following conditions: P( _lk = u{i) IY) = ^A ∑∑∑«Α( ^σ -ι ¹ ' ^σ ί ² )χ| ( ^σ λ ¹ ' ^σ '¾ ₊ ^(Τ λ- ² ' ^σ λ ₊ ι ² ' _ί ) ? _{Α +} ι(σ _{ί +} ^σ Α ₊ ι ² ) The information bits after interleaving must meet the following conditions: P(u _2k = u(j) IY) σ ί ^σ k Under multipath conditions: p(y _k I || )

Side information needs to meet the following conditions: L ^e {YI "(!·)) = P{u _lk = u(i) IY)~P(u _lk = "(/)) L ^e (YI u{j)) = P{u _2k = u{j) IY)-P(u _2k = u(j)) During iterative decoding, the sum of each 3 side information will be used as the prior information of another 1 channel information, namely: p(u _lk = u, (0) = Jr «JI )+ ("(ζ ) I y ₂ )+L7 (u(j) I y ₂ ) Similarly, each path of prior information in the other three paths of information bits is equal to the sum of the other three paths of side information. 12. The method according to claim 5, wherein said decoding the received mixed signal ' at the receiving end comprises: Filtering, radio frequency and intermediate frequency demodulation, and despreading can be performed on the received mixed signal at the receiving end, and the APP of the processed baseband signal is calculated; the decoding includes 2 loops, and iterative decoding is performed on these 2 loops; in: The joint probability density needs to meet the following conditions: r!(o- _k ^l

σ _k ² ,uj)p{u _xk = u(i))p(u _2k = "( )) p(y _k I );

The posterior probability needs to meet the following conditions: P(u _lk = (i),u _2k = u(j) I 7) Information bits need to meet the following conditions: P{ _xk = u{i) IY) The information bits after interleaving need to meet the following conditions: P(u _2k = (j) IY) Under multipath conditions: p{y _k I ,u _t ,a _k ² , _Uj ) = (πΝ ₀ )~ ^{Μ ex} P(~ II )

Side information needs to meet the following conditions: L ^e (YI "(0) = P( _Uc = u(i) IY)-P{u _xk = ιι(0) L ^e (YI u(j)) = P(u _2k = u(j) IY)-P(u _2k = u(j)) There are two side information outputs during iterative decoding, which are respectively used as prior information for the next iterative decoding. 13. The method according to any one of claims 1 to 12, characterized in that, the TURBO space-time coding can be recursive space-time convolutional coding. 14. A full-rate TURBO space-time encoding device, including a transmitting device and a receiving device, characterized in that: the transmitting device includes at least a TURBO space-time encoder and a signal interleaver, the TURBO space-time encoder encodes the transmitted signal, and the signal interleaver encodes the transmitted signal The signal is interleaved to form a mixed signal of encoded information and interleaved encoded information; The receiving device decodes the received mixed signal, and needs to recover the side information of the corresponding signal from the received mixed signal during decoding. 15. The device according to claim 14, characterized in that, the transmitting device at least includes a TURBO space-time encoder and a signal interleaver means: the TURBO space-time encoder and the signal interleaver can form a serial cascaded TURBO space-time code device. 16. The device according to claim 14, characterized in that, the transmitting device at least includes a TURBO space-time encoder and a signal interleaver means: the TURBO space-time encoder and the signal interleaver can form a parallel concatenated TURBO space-time encoding device . 17. The device according to claim 14, characterized in that, the transmitting device comprises: a TURBO time-space encoding device in serial concatenation composed of a TURBO time-space encoder and a source interleaver, Modulation and extension device, channel interleaver; where: The transmitted signal is transmitted from the corresponding antenna after being encoded by the TURBO space-time encoding device, modulated and expanded by the modulation and expansion device, and interleaved by the channel interleaver through the serial concatenation of the TURBO space-time encoder and the source interleaver. 18. The device according to claim 14, characterized in that, the transmitting device comprises: a parallel concatenated TURBO time-space encoding device composed of a TURBO time-space encoder and a source interleaver, a modulation and expansion device, and a channel interleaver; in: The transmitted signal is encoded by the parallel cascaded TURBO space-time encoding device formed by the TURBO space-time encoder and the source interleaver, modulated and expanded by the modulation and expansion device, and interleaved by the channel interleaver, and then transmitted from the corresponding antenna. 19. The device according to any one of claims 14 to 18, wherein the receiving device at least includes: an extended LOG-MAP decoding device, and the extended LOG-MAP decoding device can receive The mixed signal is decoded. 20. The device according to claim 19, wherein the extended LOG-MAP decoding device can be an extended 2-dimensional LOG-MAP decoding device, which includes a matched filter, an APP calculator, a solution interleaver, adder, interleaver; When decoding: Iterative decoding is performed on 4 loops. 21. The device according to claim 19, wherein the extended LOG-MAP decoding device can be an extended 2-dimensional LOG-MAP decoding device, which includes a matched filter, an APP calculator, a solution interleaver, adder, interleaver; When decoding: Iterative decoding is performed on 2 loops.