WO2003088503A1

WO2003088503A1 - A method and device for space-time-frequency turbo encoding

Info

Publication number: WO2003088503A1
Application number: PCT/CN2002/000239
Authority: WO
Inventors: Yonghui Li; Yi Li
Original assignee: Linkair Communications, Inc.
Priority date: 2002-04-05
Filing date: 2002-04-05
Publication date: 2003-10-23
Also published as: CN1555605A; AU2002252946A1

Abstract

A method and device for space-time-frequency turbo encoding, wherein: coding input bit in the cascaded space-time trellis by the transmitting terminal; when coding, the inside and outside code in cascade is the space-time trellis code, and combined encoding by way of the frequency domain as a dimension; decoding the receiving signal in the receiving terminal. The present invention extends space-time encoding to the frequency domain, it has the advantage of making more flexible design space for space-time encoding, more advancing systemic spectra efficiency and obtaining more diversity gain and encoding gain.

Description

Time and space frequency TURBO coding method and device

Technical field

The present invention relates to the field of communication technology, and in particular, to a serial and parallel space-time-frequency coding method for a communication system, and in particular to a time-space-frequency TURBO coding method and device. Background technique

In communication systems, the existing anti-fading schemes mainly use diversity technology, especially the space-time coding technology in diversity technology, see references [13], [14]. In the prior art, all are described by space-time coding, and No one is involved in the field of space-time-frequency coding. Summary of the Invention

An object of the present invention is to provide a time-space-frequency TURBO coding method and device. In fact, extending the space-time coding to the frequency domain can provide more flexible design space for space-time coding, greatly improve the spectral efficiency of the system, and obtain greater diversity gain and coding gain.

The technical solution of the present invention is: A spatio-temporal frequency TURBO coding method, which includes: spatio-temporal TRELLIS coding for concatenating input bits at the transmitting end; when coding, the concatenated internal and external codes are both spatio-temporal TRELLIS coding, and the frequency domain is used as One dimension of the coding is jointly coded; the receiving end decodes the received signal.

The spatio-temporal TRELLIS coding for concatenating input bits by the transmitting end refers to the spatio-temporal TRELLIS coding of the concatenating input bits in parallel at the transmitting end, which respectively modulate two spatio-temporal TRELLIS encoded signals before and after interleaving to two On the carrier; at the receiving end, two space-time TRELLIS coded signals before and after interleaving can be recovered respectively, which constitutes space-time frequency TURBO coding.

The spatio-temporal TRELLIS coding for concatenating input bits at the transmitting end refers to the spatio-temporal TRELLIS coding for serial concatenation of the input bits at the transmitting end, where the outer code is the information and check symbol formed after the spatio-temporal TRELLIS encoding After being interleaved, they are respectively subjected to space-time TRELLIS coding, and then modulated and transmitted on two carriers.

The transmitting space-time TRELLIS encoding of the input bits in parallel concatenation may also refer to: The transmitting end may perform time-space TRELLIS encoding of the input bits in parallel concatenation capable of transmitting one information symbol and three check symbols, where: By adopting modulation of two carriers, two space-time TRELLIS coded signals before interleaving and two space-time TRELLIS coded signals after interleaving can be recovered, and then modulated and transmitted on two carriers.

The decoding of the received signal by the receiving end means that: the receiving end can advance the received signal Time-space-frequency LOG-MAP decoding.

For parallel concatenated space-time-frequency TURBO coding, the receiving terminal decoding the received signal means that the receiving terminal can perform symbol-level LOG-MAP decoding on the received signal;

The decoding may be an iterative decoding, and the iterative decoding shall satisfy the following conditions:

Lc (u _k = u (i) 17) = log (p (u _k = u (i) | 7)) = log ^ p (u _k = u (i), a _k , a _{k + l} | 7) ) = l. g (A exp (a _A. (a _k ) + β _Μ (σ _Μ ) + fl 'σ _Μ , y _k )))

― Max-- _.

= h + ( _k (a _k ) + β _Μ (σ _Μ ) + γ (a _k , σ _Μ , y _k ))

k

In the above formula, summing "(0, we get:

― ^ Max _ ―

h = log (/ = -2, (σ,) + β _Μ (σ _{ί + 1} ) + f _k (a _k , σ _Μ , y _k )) ^ (^ =) |?), The side information y _A .l "(0) needs to be used in the iteration, and the prior information can be set to be. Ij

Le (y _k | u (i)) = Lc (u _k = u (i) | Y) ~ Lo (u _k = u (i)).

When deciding, the maximum likelihood decision criterion at the symbol level is used.

The largest is output as a decision symbol at time k;

For the initial state of ^, Α, the tail bit is forced to zero for each RSC encoder. At this time:)

A 1, <y _k = °

^ ^{) = (} ο, _σΑ other values

If there is a parallel path in the decoding, it is sufficient to treat the parallel path as an ordinary branch, but it is necessary to add an item to sum the parallel branches in all relevant formulas for summing states.

For serial space-time-frequency TURBO coding, the receiving terminal decoding the received signal refers to: the receiving terminal can perform bit-level LOG-MAP decoding on the received signal;

The decoding may be an iterative decoding, and the steps of the iterative decoding are:

(1) The signals received by carrier 1 and carrier 2 are respectively filtered by the receiving matched filter, and APP calculations are performed respectively.

p (u _k ; 0) = p (u = u _k I ^) = A∑∑ «, (σ,) β _Μ (σ _{ί + Ι} ) γ [(σ _,, σ _Μ , y _k ), calculated Internal Code Space-time coded codewords 4 ^1);, 4 ²⁾ '' symbol-level posterior probability, and then use the formula

k.

Pi ^ IF) = Π p (b _t I 7), which is converted to a bit-level likelihood ratio to obtain the full posterior probability, respectively.

1 = 1

Likelihood ratio

^ ²⁾ ; J) = 0;

(2) Then use the formula: j = ι "·· Α

Pliu _k U) = oo). ) = ln- · ^{) = 1; 0)} j = l, ..., n ₀

p _k ^e (c _k (j) = 0; O)

Compute side information,

;

(3) 1 side information of the calculated inner code 4 ^{1) £} ("); 0), f ^e (u _l u, o) is deinterleaved as the prior information of the outer code ^., ^. (Cr /);), (C) /);), where the superscript "0" indicates a foreign code;

(4) Use the formula: (;) = f ^ (4 to calculate 4 (;). When the posterior likelihood information of the outer code is calculated, 1 ₄ (^; /) is always zero; the obtained ^ _k (u _k ; I), brought into the formula λί (c (y); O) = max l _k (a _k ) + β _Μ (σ _Μ ) + λ, (u _k ; J) + _k (c, (σ,) ; /)]

-max [¾ (^) + β _Μ (σ _Μ ) + _k (u _k ; Ι) + λ _1ζ (c _k (a _k ); /)], we get 1 ^ (φ ·); 0), j = l,-, n ₀ \ Then bring into the formula:

(c (J '); 0) = (c (); O) — ((); J), (c (_ /); O) is calculated, 7 = 1,-, « ₀ ; / I =, convert the likelihood ratio of side information to the posterior probability of the symbol

/ = 1

(E) The _P ^e c _k 0, is first serial-parallel conversion, to obtain _{^{0 fc; O), /)}} e (; O), are obtained after the interleaving, the interleaving information of this were used as inner code coded temporal frequency Prior Information

;

(6) Repeat the 5 steps described above in subsequent iterations;

(7) At the last iteration, output the outer code of l ("0); O), j = l,-, and use the following method to make a decision: _u- gate ₌ (i, when> o

"-o, when _A (> o ° and then return to 1, decode the next frame.

For serial space-time-frequency TURBO coding, the receiving terminal decoding the received signal refers to: the receiving terminal can perform symbol-level LOG-MAP decoding on the received signal;

At this time, all the probability information is expressed by the posterior probability at the symbol level, but the bit-likelihood ratio is not used. The formula is: p _k 0, = ptJ;. P ^u _k I calculates the space-time coded codeword of the inner code ^ '', 4 ²⁾ 'Symbol-level posterior probability side information 0 _A ; O), p ^{) e} (u _k ; 0), The likelihood information needs to be calculated again, but its de-interleaving is used as the prior information of the outer code decoder

A (c: ² ). ; /);

When decoding in outer code:

¾ ₊ ι) = max (, (σ _{/ £} ) + p _k (u _k ; I) + p _k (c _k (a _k ); J) (σ _Α .) = Max (¾ _{+ I} (a _k ) + p _k (u _k ; I) + p _k (c _k (a _k ); I) price,, y _k ) = hp _k (c; I) p _k (u; I)

The calculated posterior probability of the full information is:

Pt ( ^c ; 0) = max [a _k (a _k ) + β _Μ (σ _Μ ) + p _k (u _k ; I) + p _k (c _k (σ,); /)]

° ((σ _¾ ) = 1

One person, n

-: (() = 0) + A + i ( ^σ Μ) + Λ (¾;) + P _k (c _k (σ,); /) pl (c; 0) = pt (c; 0) -p _k (c; I), which is always zero in the iteration of the outer code; p _k ^e {c _k ; O) is serial-parallel converted and interleaved as the prior information of the space-time-frequency encoding of the inner code

, Iterative process after.

A spatio-temporal frequency TURBO encoding device, wherein: a transmitting end includes at least a spatio-temporal TRELLIS encoder and an interleaver, and the spatio-temporal TRELLIS encoder and the interleaver form a cascaded spatio-temporal TRELLIS encoding device; during encoding: input bits are respectively input into the spatio-temporal TRELLIS An encoder and an interleaver, and output after encoding; the receiving end includes at least a time-space-frequency decoding device based on LOG-MAP decoding.

The cascaded spatio-temporal TRELLIS encoding device refers to: a parallel-cascaded spatio-temporal TRELLIS encoding device, which is composed of a spatio-temporal TRELLIS encoder, an interleaver, a modulator, and an antenna; during encoding: input bits are input into the spatio-temporal TRELLIS encoder and Interleaver, the bits of the input space-time TRELLIS encoder are encoded and output to the modulator, and the signal output by the modulator is sent out via the antenna; The bit interleaved into the interleaver needs to be input into another space-time TRELLIS encoder, and after being encoded, it is output to another modulator, and the signal output by the modulator is sent through another antenna.

The cascaded spatio-temporal TRELLIS encoding device refers to: a serially cascaded spatio-temporal TRELLIS encoding device, which is composed of a spatio-temporal TRELLIS encoder, an interleaver, a modulator, and an antenna; during encoding: input bits are first input into the spatio-temporal TRELLIS encoder The outputs of the space-time TRELLIS encoder are the inputs of at least two interleavers, the outputs of the interleaver are the inputs of at least two other space-time TRELLIS encoders, and the outputs of the at least two space-time TRELLIS encoders are at least two Input of two modulators, and the signals output by the at least two modulators are respectively sent through at least two antennas.

The cascaded space-time TRELLIS encoding device refers to: a space-time TRELLIS encoding device capable of transmitting one information symbol and three check symbols in parallel, which is composed of a space-time TRELLIS encoder, interleaver, modulator, and antenna ; When encoding: input bits are input to a space-time TRELLIS encoder and an interleaver respectively, the bits of the input space-time TRELLIS encoder are encoded and output to a modulator, and the signal output by the modulator is sent through an antenna;

After the bits of the input interleaver are interleaved, the second space-time TRELLIS encoder and the second interleaver must be input respectively. The output of the second interleaver is the input of the third space-time TRELLIS encoder. The output and the output of the third space-time TRELLIS encoder are the input of the second modulator, and the signal output by the second modulator is sent by the second antenna.

The decoding device may be a single-rate parallel space-time-frequency TURBO decoder; it is composed of a matched filter, an APP calculator, an interleaver, an deinterleaver, and a discriminating device; when decoding: carrier 1 and carrier 2 receive The signals pass through the receiving matched filters 1, 2 and enter the two APP calculators, and the decoding is completed by iterative decoding based on the LOG-MAP decoding algorithm.

The decoding device may be a serial space-time-frequency TURBO decoder; it is composed of a matched filter, an APP calculator, an interleaver, an de-interleaver, and a discriminating device; at the time of decoding: carrier 1 and carrier 2 receive The signals enter the two APP calculators through the receiving matched filters 1 and 2, respectively. The outputs of the two APP calculators are the inputs of the deinterleavers 1 and 2, respectively, and the outputs of the deinterleavers 1 and 2 are common. Become the input of the third APP calculator, and complete the decoding by iterative decoding based on the LOG-MAP decoding algorithm.

The beneficial effects of the present invention are as follows: The present invention extends space-time coding to the frequency domain, which can provide more flexible design space for space-time coding, greatly improve the spectral efficiency of the system and obtain greater diversity gain and coding gain. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a block diagram of the parallel space-time-frequency coding structure;

Figure 2 is a block diagram of the serial space-time-frequency coding structure;

Figure 3 is a block diagram of a parallel space-time-frequency coding structure that processes one information symbol and three check symbols; Figure 4 is a block diagram of a single-rate parallel space-time-frequency TURBO decoder;

FIG. 5 is a structural block diagram of a serial space-time-frequency decoder;

Figure 6 shows the FER performance curve of serial-parallel spatiotemporal frequency coding at a moving speed of 5km / h; Figure 7 shows the FER performance curve of serial-parallel spatiotemporal frequency coding at a moving speed of 60km / h.

detailed description

I. Serial and parallel space-time-frequency coding structure:

In serial-parallel space-time-frequency coding, the concatenated internal and external codes are all space-time TRELLIS codes. However, at this time, the frequency domain is also considered as a coding dimension to jointly code.

The structure of parallel space-time-frequency coding is shown in Figure 1. In the figure, we can see that by modulating two carriers, we can recover the two space-time-coded signals before and after interleaving separately. Therefore, this actually constitutes Spatio-temporal frequency TURBO coding. In the later decoding algorithm, we can see that the decoding algorithm can be greatly simplified by using the above single-rate coding scheme. In the above scheme, in a single-path channel, when two receiving antennas are used, a coding gain of 1/2 and an 8-diversity gain can be achieved.

Figure 2 shows the serial space-time-frequency encoding structure. In a serial space-time-frequency encoder, the information and check symbols formed after space-time encoding of the outer code are interleaved and then pass through two space-time encoders. Modulate and transmit on each carrier. The two interleavings shown in the figure should be the same, or the information of the outer code and the checksum can be first interleaved, and then separated.

Parallel space-time-frequency coding can have another coding scheme, as shown in Figure 3. At this time, similar to the 1/4 TURBO encoder, it is different from the previous structure. At this time, an information symbol and 3 checksums are passed. Symbols, P strips lower the coding rate, but increase the complexity of decoding.

II. LOG-MAP decoding of symbol-level parallel space-time-frequency TURBO coding:

Above we have given serial and parallel space-time-frequency encoders. Here we give symbol-level LOG-MAP decoding algorithms for the above parallel space-time-frequency encoders:

In [8] [9] [10], a general MAP decoding algorithm based on the SIS0 model for concatenated codes is given. The present invention will draw on the SIS0 model and the MAP decoding algorithm and apply it to space-time Frequency in the LOG-MAP decoding algorithm. In the following derivation, we do not make a detailed derivation of the LOG-MAP decoding algorithm ([15]) common to TURBO codes, but put the main space on the symbol-level LOG-MAP decoding algorithm.

At time k, the posterior probability of the information symbol is:

P (u _k = u {

(1) where pu _k = u (i), o _k , a _m IY) represents the joint probability distribution of u _k , σ,, σ, ₊₁ when the received signal + is known. The following derivation is compared with the ordinary The decoding algorithm of LOG-MAP of TURBO code is the same. We only give the result. For details, please refer to the decoding algorithm of BCJR [1] [2].

In formula (1), applying the Bayes rule, we get:

P (u _k = u (i), a _k , σ _{4 + 1} I Ϋ) = hp (u _k = u (i), a _k , a _{k + 1} , Ϋ) (2) where h satisfies

^ ΣΣΣ ^-= "'), σ„ σ, ₊₁ , 7) = 1 (3) Will we? Divided into f = (―, then

P (u _k = u (i), a _k , σ _Α . ₊₁ , 7) = p (u _k = u (i), a _k , σ _Μ ~, y _k> f _k ⁺ ) ( ₄ )

= P (Y _k ⁺ I u _k = u (i), a _k , a _{k + l} , Y _k ~, y _k ) p (u _k = u (i) _k , a _{k + 1} , y _k \ a _k , Y _k ~) p (a _k , Y _k ) According to the properties of the Markov chain, if σ _ω is known, then ⁺ will not depend on other parameters.

P (Y _k ⁺ I u _k = u (i), a _k , a _M , Y _k ', y _k ) = p (f _k ⁺ \ σ _Μ )

Similarly, P (¾ = u (i) _k , ^ _{k + l} , y _k \ a _k , Y _k ~) = p (u _k = u (i) _k , a _M , y _k \ a _k ),

If we define

rk ',,) = p ( ^u k = "(! ·)''y _k I _k )

a _k (a _k ) = p (a _k , Y ,;) Then, we can write (2) as follows:

P {u _k = "(0, o- _k , σ _Μ I Υ) = ha _k (a _k ) β _ι (a _{k + i} ) γ [(a _k , a _{k + l} , y _k )

At time k, when the input is ^), the state proceeds to _σ έ σ Α _{+ 1} joint probability distribution can be expressed as:

ή, ^σ ι, y _k )

= "( ^? :), ^A k ' ^σ Μ) p ( ^u k =" (01. _k , ₊₁ ) ρ (σ _Μ I σ (5) If we assume that the input is "(0, in the TRELLIS grid On the graph, the state σ _{Α is} shifted to σ _Μ , so that (5) can be expressed as ή (^ k, ^σ ί ₊ ι, y _k ) = p (y _k I "(0, σ _λ .) p (u _k =)) (6) i7 (3 _{/ £} | _w () ,) Represents the conditional probability, which represents the probability at time k, in the state, when the input is _M (0, the received signal is Λ

Because _Λ = # + so P (I u (i), a _k ) = (πΝ ₀ Υ ^Μ exp (-L | k _c - _k S _k ()

N,

M in the above formula is the number of receiving antennas.

If for each fading channel, there are L separable multipaths, the above formula will become:

P (y _k I u (i), a _k ) -H _H ¾ ')

In the above formula, each variable with / represents the corresponding / th path signal, so it is only necessary to add L separable multipath metrics when calculating the metric.

Using the LOG-MAP decoding algorithm, we define:

Yk (σ ₄ , σ _Α . ₊₁ , y _k ) = \ og (y _k (a _k , σ _Μ , y _k )) can be obtained

l ^Q g (∑ exp (¾ (<y _k ) + f _k (σ _,, σ _Μ , y _k ))

t

«Ax ( _k (a _k ) + f _k (a _k , a _{k + 1} , y _k )) Similarly,

(cr _k ) = l. g (∑ exp (¾ ₊₁ (a _k ) + f _k {a _k , a _{k + l} , y _k ))

«Max (^ ₊₁ (a _k ) + _k (c _k , σ _Μ , y _k )) Because ₊₁ (σ), (σ _έ ) increases gradually during the iteration process, in order to prevent ά _Μ ( σ _Μ), overflow, they must be normalized, the so-called process is just minus the maximum normalized:

k '(σ _λ .) = a _k (a _k )-max a _k (a _k )

°

') = (σ,)-max β, (σ,) and' (σ and A '() are used in subsequent iterations and calculations, it has been proven that (σ _Α ) and ¾ () add or subtract a factor, not It will have any effect on the calculation of the posterior probability, and this factor will eventually be eliminated. Because the state σ ₄ + 1 at time k + 1 is the transition state when the input is "(0, so in the sum of (1), we only need to sum the state ^, at this time ( 1) The expression of the formula becomes logarithmic operation:

Lc (u _k = u (i) I Ϋ) = log (p (u _k = u (i) | 7)) = log ^ p (u _k = u (i), a _k , a _{k + l} 1 7 ))

= l ° g (^ ∑ ex (¾ (σ _Α .) + ¾ ₊₁ (σ, ₊₁ ) + γ [p _k , a _{k + l} , y _k ))) (η)

― Max — a _.

= h + ( _k (σ _{/ £} ) + β _Μ (a _{k + l} ) + f _k (σ _{/ £} , σ _Μ , y _k )) In the above formula, we can sum up "(0, we can find

-^-, max _ — _.

Λ = log (/ z) = -2 ^ (a _k (a _k ) + β _Μ (σ _{Α + 1} ) + γ (σ _,, σ _Μ , y _k ))

'· ^G k

At this time, we can perform iterative decoding. In formula (7), the full information Lc {u _k = u (i) I Ϋ) is obtained. The side information Le (y _k \ u (i )), We assume that the prior information is Lo (u _k = u (i))

Le (y _k | u (i)) = Lc (u _k = u (i) | Y) ~ Lo (u _k = u (i))

When making a decision, we use the maximum likelihood decision criterion at the symbol level, that is, take the largest posterior probability p {u _k =} |) "(0 as the decision symbol output at time k.

The initial state is similar to the traditional TURBO code. Because we use recursive convolutional codes, the traditional method of adding zero tail bits cannot guarantee that the state of the system returns to zero. In the TURBO code, if no TRELLIS state is terminated, the system performance will be greatly deteriorated [3], [4], [5]. In order to simplify the design of the system, we only interleave the information bits when interleaving. Each RSC encoder has its own tail bit. Although this will bring a loss of performance [6] [7], it will simplify the system. design. In our scheme, the state of each RSC is terminated, and the forced state return method is adopted, because we know the state at the end of each RSC encoder, so we can force the state to zero by adding a tail bit. The algorithm used in the present invention is not optimal. The state of the optimal TURBO code terminates, and tail bits [1] [3] need to be added before interleaving. This can ensure that TURBO has the maximum free distance, because at this time, the equivalent Therefore, we know the TRELLIS trellis of the entire TURBO code, which is the termination of the state of the entire trur code of the TURBO code. This slightly complex state return algorithm for TURBO codes needs to be designed together with the interleaver to ensure optimal performance. For specific algorithms, please refer to the above references.

In the present invention, we use the method of Case, at this time

One. _k = 0

^{Ω <3} ( ^σί ') ^{= {} 0, σ _{/ £} are other values

1, σ ₄ = 0

^^^ ^, ^^ are other values

Figure 4 shows the decoding structure of single-rate parallel spatiotemporal frequency. In the case of a parallel path in the decoder, we only need to treat the parallel path as a common branch. At this time, in all the above formulas for summing states, You should also add a sum of parallel branches. At this time, all other formulas can be applied to the case with parallel paths without any changes.

III. LOG-MAP decoding of symbol-level serial space-time-frequency TURBO coding:

Above, we introduced the parallel space-time-frequency LOG-MAP decoding algorithm. Here we introduce the serial space-time-frequency TURBO coding LOG-MAP decoding algorithm. The decoding process of serial spatiotemporal TURBO coding is slightly more complicated than the decoding of parallel spatiotemporal TURBO coding, because during the decoding process, the likelihood ratio of the bits and the posterior probability of the symbol need to be repeated. Conversions between calculations. However, the performance of serial space-time-frequency coding is better than parallel space-time-frequency coding. This can be seen from the simulations given below.

The symbol-level serial concatenated TURBO code decoding algorithm has been introduced in [11] [12] [13]. Since the spatio-temporal TURBO coding is symbol-based coding, the traditional concept is that its decoding can use the symbol-based LOG-MAP decoding algorithm.

Here, to break the framework of traditional concepts, a bit-level serial concatenated time-frequency TURBO code decoding algorithm is first given. This decoding algorithm is more complicated than the symbol-level decoding algorithm. This algorithm is introduced. The intention is to explain that the spatio-temporal frequency coding can use either a symbol-level LOG-MAP decoding algorithm or a bit-level LOG-MAP decoding algorithm. And based on this decoding algorithm, a symbol-level decoding algorithm can be easily derived. The symbol-level LOG-MAP decoding algorithm will be given below based on this algorithm.

In this decoding algorithm, we will use the bit-level likelihood ratio calculation, and also calculate the symbol-level posterior probability, so the posterior probability of a given symbol is given below to find the bit-level likelihood. The process of likelihood ratio, and the likelihood ratio of a known bit level, the process of calculating the posterior probability of a symbol.

Given the posterior probability of the symbol, find the bit-level likelihood ratio:

Assume that the symbol set is S-, ^, ..., ^}, and each symbol is composed of k. It consists of bits, denoted as {&, ^, ...,:. }. Also set the posterior probability of N symbols in symbol level S as P = (p _i , p ₂ ,-, p _N ) = (p (s _l \ Y), p (s ₂ \ Y),-, p (s _N \ Y)}, the following gives the / bit in the symbol Likelihood ratio l,, λ _ P, = Y) _ good (9)

'"^ = 017)" Σp ( _Si \ Y) In the above formula, e {b / = 1} represents the set of all symbols whose symbol / bit is 1. Knowing the back-face f rate of the symbol, find the bit-level likelihood ratio:

The definition of the symbol set and its elements is the same as that of the face. Suppose we know the likelihood of the posterior probability of the / bit, first find

1 + β ^λ '

1

p (b _l = 0 \ Y) =

\ + ε ^λ ·

We can write the above two formulas as a general formula expressed by b _t , p (b, IY) = ⁶

1 + β ^λ '

If the symbol is composed of k _Q bits, it is denoted as {b, ...,} '' J: p (s _i \ Y) = flp (b _l \ Y) (10)

1 = 1

(9), (10) Both formulas give the signed posterior probability calculation algorithm of bit-level likelihood ratio and the posterior probability of symbol by bit likelihood ratio algorithm, which will be used in the subsequent calculations. Used.

Space-time-frequency TURBO-encoded bit-level LOG-MAP decoding algorithm:

In this decoding algorithm, we know the symbol-level posterior probability at the receiving end, and in the calculation and iteration of the outer code, we use the bit-likelihood ratio.

First, for the convenience of the following derivation, we first define some symbolic representations. If there is no special description, the meaning of these symbols is the meaning introduced below:

u: input information bits (w (l), M (2), ..., u (k ₀ )

c: code words (c (l), c (2), ..., c (i.))

/: Represents the input information of the decoder

0: indicates the output information of the decoder (including full information and side information)

u (j): input information bit u: jth bit

c (j): represents the j-th bit of the codeword c after encoding Likelihood ratio representing posterior probability

P _k ^A Q: represents the full posterior probability

(): Indicates full likelihood ratio information

Similar to the above derivation, at time k, the posterior probability of the information symbol is:

(11) in the above formula belongs to the symbol set ^

We can expand the expression of the summation symbol on the right side of the equation into the expression of _Μ , γ [, that is: ^ ("So:

Ρί (

_k , σ _Μ , y _k ) ( ₁₂ ) In the above formula, β _Μ , has the same meaning and expression as above. The key lies in the calculation of ^.

In the bit-level LOG-MAP decoding algorithm, both the bit-level likelihood ratio and the symbol-level posterior probability calculated by the above formula are used in the iteration, and then the symbol-level posterior given above is used. The conversion formula (9) from the test probability to the bit-level likelihood ratio is converted.

On top, we get

Price ' ^σ Μ,) = Pu (Λ I "= ⁱ , ^σ *, ^σ Μ) p _k ( ^u ^ ^u k \ k, ^σ Μ) Pk ( ^σ λ- ₊ ι \ k) ( ¹³ ) If we assume When the input symbol is ^, on the TRELLIS trellis, transition from the state σ _λ to ₊₁ . In this way, the above formula can be expressed as

r _k ^l ^ _k , a _{k + l} , y _k ) = p _k (y _k \ u _k , a _k ) p _k (u = u _k ) (14) ρ ( _Λ 1 ^,) in the above formula represents Conditional probability, which represents the probability that the received signal is Λ at time k and in the state cr _t when the input is ^

Because (Λ I = exp (-|| j || ² ) (15), M is the number of receiving antennas.

At the same time, and /? 々 iteration expression is as follows

« _{Ί +} ι) * max (, (σ,) + f _k (σ _,, σ _ω , y _k )) (16) _k (σ ₄ ) «Band (¾ ₊₁ (σ _Α ) +, ( _Α , σ _M , y _k )) (17) Using the formula (12), we can find the full posterior probability of the symbol ^ (; O ), Then the side information can be obtained as:

pt (u _k ; 0) = pt (u _k ; 0) _-Pk (u _k ; I) (17-2) Then using [9], we can find the likelihood ratio of the side information

For each carrier, we can calculate (^ (); 0). If we set the likelihood ratios of the side information calculated by the two carriers as:

And 4 ^{2) e} ("■); 0)

If the mnemonic code is output to the inner code space-time encoder 1, and the codewords of the inner code space-time encoder 1 are respectively denoted as _c °, c ^{) 0} , then ( ^{1) e} (u _k U); o), ^{2 ) e} («, ω; o)) are ^ calculated by the inner code decoders 1, 2 respectively. , ^). Probability information.

In the entire decoding process of the outer code, the likelihood ratio is used for calculation. Therefore, the expression of the posterior probability likelihood ratio derived from the likelihood ratio is given below.

At this time, except that the calculation of ^ (, σ _{ί + 1} , _Λ ) needs to be converted from the symbol-level conditional probability representation to the bit-level likelihood ratio representation, other calculations are basically the same as the previous ones.

In the previous, it has been given

ϊ [(o- _k ,, y _k ) = p _k (y _k \ u _k , a _k ) p (u _k = u) = p _k (y _k | c _k ) _Pk (u; I)

() In the above formula indicates that the state is 0 " _t , and the output when the input is ^.

P ( ^c k)

In the above formula, ^ (, ₊₁ , ^) = (»;) ( ²⁰ ) Use the conversion relationship between the posterior probability of the symbol and the likelihood ratio (9) to bring the posterior probability expressed by the likelihood ratio into In (20), we can get

(u (j); 0) = max [a _k (a _k ) + (σ, ₊₁ ) + γ [(a _k , a, y _k )] =,,) + D ( ^σ "ι) + 4 ½; Ή * (c _k (a _k ); /)] I, _η [) + d ( ^σ " ι) + · (¾; ^/ ) + Κ ( σ _Α ); /)]

j =,-, (2D In the above formula,

Similarly, we get

A _k (c (j); 0) = max [a _k (a _k ) + ¾ ₊₁ (σ _{/ £ + 1} ) + ^ ( _Μ ,; /) + λ _{! (} (C _k (a _k ); /)]

Person-: c _A (J) ( _A ) -l

-Max, _n [¾ (σ ^) + β _Μ (σ _{Α + 1} ) + ^ (Μ ^; /) + ^ ( _k (a _k ); /)] j '= l, ···, ". (24) The iterative expression of A in the formula becomes:

a _{k + l} (σ _Μ ) = max (a, (a _k ) + _k (u _k ; I) + X _k (c _k (a _k ); I) k (^ k) = max (¾ ₊₁ ( a _k ) + _k (u _k ; I) + X _k (c _k (a _k ); /) At the same time, the side information calculation process in the iteration process is as follows:

(uU); 0) = X ^A _k (uU); 0) _-k (u _k (7); /) j = l,-, k ₀ (25) λ (c (j); O) = ^A _k (c (j); O)-X _k (c _k (;);) j = h-, n ₀ (26) Let us explain the process of serial space-time-frequency decoding with reference to FIG. 5. The LOG-MAP decoding process of serial space-time-frequency TURBO coding is:

(1) The signals received by carrier 1 and carrier 2 enter the two APP calculation modules through the receiving matched filters 1, 2 respectively, and use formula (12) to calculate the codewords _c ', _{c of the} inner code space-time encoders 1 and 2. The symbol-level posterior-risk ratio is then converted to the bit-level likelihood ratio using the formula (10) to obtain the likelihood ratio of the full posterior probability ("■); 0), _ / = 1, respectively. · 'Α, at initial iteration, let = 0,

Q.

(2) Then use (18), (19) to calculate the side information 4 ^{1) 2} (); O), d); O). (3) The 2 side information of the inner code calculated in step 2 4 ^{1) £} (J '); O),

Deinterleaving is used as the outer code ^. ^^. A priori information ^ (^. (;), C ⁰ u); D, where The superscript "0" indicates a foreign code.

(4) Use formula (23) to calculate (; /). When calculating the posterior likelihood information of the outer code, A _k (u _k; I) is always zero; 4 (; /), (u _k ; I), brought into (24) to get λ]); 0), j = l,-, n ₀ ', and then brought into (26), calculated to get Ι Φ ·); 0), = l , —, W. ; Use [10] to convert the likelihood ratio of side information to the posterior probability of the symbol (; O)

(5) ^ _Ct ; O) is first serial-to-parallel converted to get, respectively, obtained through the interleaver 1, 2, ^ ^{) 2} (; O), ( _¾ ; O), and use the interleaved information as internal Prior information of code space-time frequency encoders 1, 2;

(VI) in a subsequent iteration, repeating ^2--5 steps.

(7) At the last iteration, output the outer code of j = l ", k ₀ , and use the following method to make a decision k

Then return to 1, and decode the next frame.

The symbol-level LOG-MAP decoding algorithm is derived from the bit-level LOG-MAP decoding algorithm: A bit-level and symbol-level mixed LOG-MAP decoding algorithm is given above. In this section, this algorithm is derived Symbol-level LOG-MAP decoding algorithm. At this time, all the probability information is expressed by the posterior probability at the symbol level, but no bit-level likelihood ratio is used.

Use (17-2) to calculate the side information ₄ of the posterior probability of the code character number level of the inner code spatio-temporal encoders 1 and 2; 0), p ^{) e} (u _k -0).然信息。 Natural information. Instead, the inverse interleaving is used as the prior information of the outer code decoder, _Pk (c ^{) 0-} ).

In the outer code decoder,

¾ · ₊ ι) = max (a _k (σ,) + p _k {u _k ; I) + p _k (c _k (a _k ); /)

.

(σ _Α .) = max (¾ ₊₁ (a _k ) + _Pk (u _k ; J) + p _k (c _k (a _k ); /)

Price (σ, y _k ) = hp _k (c; I) p _k (u; I)

The calculated posterior probability of the full information is (in the iteration of the outer code, ρ ^, 'Γ) is always zero)

Pt ( ^c ; O) = m ^ c [a _k (a _k ) + ¾ ₊₁ (σ _Μ ) + p _k (u _k ; I) + p _k (c _k (a _k ); /)]

-max [a _k (σ,) + β _Μ (σ, ₊₁ ) + p _k (u _k ; I) + p _k (c, (σ,); I) σ * ¾ · Ο) (σ · * :) = ⁰ pt (c; 0) = pt (c; 0) -p _k (c; l)

^ (; O) serial-to-parallel conversion and interleaving are used as a priori information of the inner code space-time frequency encoders 1, 2

; I), the subsequent iteration process is the same as in section 3.

IV. Simulation results and conclusion analysis:

The simulation results when using the parallel and serial space-time-frequency coding and decoding algorithms described above are given below. The main simulation parameters are listed in Table 1. In the following simulation results, the total power and space-time-frequency coding have been considered. The power without space-time frequency coding is the same.

The following two figures respectively show the performance comparison between parallel space-time-frequency coding and serial space-time-frequency coding and traditional space-time block coding [13] [14] (extended to two frequencies for coding).

In Figure 6, the FER performance curve of serial-parallel space-time-frequency coding at 5km / h is given. From the figure, it can be seen that at high SNR, the performance of serial space-time-frequency coding is optimal. Under the FER condition of 10E-4, the serial space-time frequency coding is about 0.5dB better than parallel, and the performance is about 4dB better than the traditional space-time block coding, and this gap will grow as the signal-to-noise ratio increases. Bigger. At 10E-5 FER, the serial space-time frequency coding is about 1.5dB better than parallel.

In Figure 7, the FER performance of serial-parallel space-time-frequency coding at a moving speed of 60 km / h is given. Curve. It can be seen from the figure that at high SNR, the serial space-time-frequency coding performance is still optimal. 5dB。 Under 10E-4 FER conditions, serial space-time frequency coding is better than parallel about 0.5dB, better than the traditional space-time block coding performance is about 1.5dB. 5dB。 10E-5 FER, serial space-time frequency coding is better than parallel about IdB, better than the traditional space-time block coding about 2.5dB.

In the previous analysis, we can know that serial time-space-frequency decoding is slightly more complicated than parallel decoding, but it is much more complicated than traditional space-time block coding. The simulation results show that the serial space-time-frequency gain is the largest, so the performance improvement comes at the cost of increased decoding complexity.

The present invention extends space-time coding to the frequency domain, which can provide more flexible design space for space-time coding, greatly improve the frequency speech efficiency of the system, and obtain greater diversity gain and coding gain.

The above specific implementations are only used to illustrate the present invention, but not intended to limit the present invention. The references involved in the present invention are as follows:

[l] .LRBa l, J.Cocke, F.Jelinek, and J.Raviv, "Optimal decoding of linear codes for minimizing symbol error rate," IEEE Transactions on Information Theory, pp.284- 287, Mar.l974.

[2] .P. Robertson and T. Worz, "Bandwidth-efficient turbo trellis-coded modulation using punctured component codes," IEEE Journal on Selected Areas in Communications, vol.16, pp.206-218, Feb.l998.

[3]. Johan Hokfelt, Ove Edfors, and Torleiv Maseng, "On the Theory and Performance of Trellis Termination Methods for Turbo Codes", IEEE JSAC, vol.19, No.5, May 2001.

[4] .AS Barbulescu and SSPietrobon, "Termination for turbo encoders," in 17 ^th Biennial Symp. Communications, Kingston, ON, Canada, May 1994, PP. 389-392.

[5] .M. Hattori, J.Murayama, and RJ.McElice, "Pseudo-random and self-terniinating and interleavers for turbo codes," in Information Theory Workshop, San Diego, CA, Feb. 1998.pp. 9- 10.

[6] .Jung.P., And NABHAN.M, "Dependence of the error performance of turbo codes on the interleaver structure in short frame transmission systems,", Electron. Lett., 1994, 30, pp.287-288.

[7] Jung.p, and NABHAN.M, "Performance evaluation of turbo codes for short frame transmission systems," Electron 丄 ett., 1994, 30, pp.l 11-113.

[8]. J. Hagenauer, P. Robertson, and L. Papke, "Iterative (Turbo) decoding of systematic convolutional codes with the MAP and SOVA algorithms," in Proceedings of the ITG Conference, VDE— Verlag, Oct. 1994.

[9]. S. Benedetto, G. Montorsi, D. Divsalar, and F. Pollara, "A soft-input soft-output maximum a posteriori (MAP) to decode parallel and serial concatenated codes," in The Telecommunications and Data Acquisition Progress Report 42-127, pp.1-20, Jet Propulsion Laboratory, Nov. 1996. [10]. S. Benedetto, G. Montorsi, D. Divsalar, and F. Pollara, "A soft-input soft -output APP module for iterative decoding of concatenated codes," IEEE Communications Letters, vol.1, pp.22 -24 ₃ Jan. 1997.

[11]. S. Benedetto, D. Divsalar, G. Montorsi, and F. Pollara, "Serial concatenated trellis coded modulation with iterative decoding: Design and Performance," in IEEE Communications Theory Mini Conference, pp.38-43, 1997 .

• [12] .S _. Benedetto _? D. Divsalar, G. Montorsi, and F. Pollara, "Serial concatenated trellis coded modulation with iterative decoding: Design and Performance," in International Symposium on Information Theory, (Ulm, Germany.) , IEEE, Juiie-July _? 1997.

[13] .V.Tarokh ₅ N.Seshadri ₃ ARCalderbank ₅ "Space-Time Codes for High Data Rate Wireless Communication: Performance Criterion and Code Construction", IEEE Trans. Inforai.Theory _? Vol.44, No. 2 _? March 1998 .

[14]. S. Alamouti, "A simple transmit diversity technique for wireless communications / 'IEEE JSAC, vol 14, No, 8,1451-1458, OcU998.

[15]. J. Hagenauer ₃ Elke Offer, and Lutz Papke, "Iterative Decoding of Binary Block and Convolutional Codes", IEEE Trans on Information Theory, Vol, 42, No. 2 March 1996.

Claims

Rights request

1. A spatio-temporal frequency TURBO coding method, comprising: a spatio-temporal TRELLIS coding for concatenating input bits at a transmitting end; when coding, the concatenated internal and external codes are both spatio-temporal TRELLIS coding, and the frequency domain is used as a dimension of the coding Joint coding

The receiving end decodes the received signal.

2. The method according to claim 1, wherein the spatio-temporal TRELLIS coding for concatenating input bits by the transmitting end refers to the spatio-temporal TRELLIS coding for concatenating input bits in parallel by the transmitting end, respectively, Spatio-temporal TRELLIS coded signals before and after interleaving are respectively modulated onto two carriers;

At the receiving end, two space-time TRELLIS coded signals before and after interleaving can be recovered respectively, which constitutes space-time frequency TURBO coding.

3. The method according to claim 1, wherein the spatio-temporal TRELLIS coding for concatenating input bits by the transmitting end refers to the spatio-temporal TRELLIS coding for serial concatenation of input bits at the transmitting end, wherein :

The information and check symbols formed by space-time TRELLIS encoding of the outer code are interleaved, and then are separately space-time TRELLIS encoded, and then modulated and transmitted on two carriers.

4. The method according to claim 1, wherein the time-space TRELLIS coding of the transmitter by performing parallel concatenation on the input bits further comprises: the transmitter can perform one information symbol and three on the input bits. Spatio-temporal TRELLIS coding of parallel concatenation of several check symbols, where:

By using the modulation of two carriers, the two space-time TRELLIS coded signals before interleaving and the two space-time TRELLIS coded signals after interleaving can be recovered, and then modulated and transmitted on the two carriers.

5. The method according to claim 1, wherein the decoding of the received signal by the receiving end means: the receiving end can perform LOG-MAP decoding of the received signal in space-time frequency.

6. The method according to claim 2 or 4, wherein the decoding of the received signal by the receiving end refers to: the receiving end can perform symbol-level parallel space-time-frequency TURBO encoding of the received signal to the LOG- MAP decoding

The decoding may be an iterative decoding, and the iterative decoding shall satisfy the following conditions: Lc (u _k = u (i) I 7) = logCp (= u (i) 17)) = log (∑ (u _A = u (i), a _k , a _{k + 1} \ Ϋ))

= log (A∑ exp (a _A. (a _k ) + β _Μ (σ, ₊₁ ) + γ ((σ _{Ι (} , a _{k + l} , y _k ))) max

= ^h + (σ _{/ £} ) + β _{! (+ 1} (σ _Μ ) + γ [(a _k , σ _Μ , y _k )) In the above formula, summing "ω, we get:

--, max one _.

h = iog (A) = ~ J

) + k (, ^Σ Μ, y _k )) can be iteratively decoded at this time, the side information e (| | M (Z ·)) needs to be used to calculate the full letter iteration, and the prior information can be set as

Le (y _k I u (i)) = Lc (u _k = u (i) | Y) ~ Lo u _k = u (i))

When deciding, the maximum likelihood decision criterion at the symbol level is adopted, that is, the maximum posterior probability 7 (^ = ') |) is taken as the decision symbol at time k;

For the initial state of;, ¾, ^, the scheme of forcing zeroing by adding tail bits to each RSC encoder is adopted at this time:

1, G _K = 0

α ° ^{) = (} ο, for other values

_ 1, a _k = 0

β ^Λσ =, ^ are other values

7. The method according to claim 3, wherein the decoding of the received signal by the receiving end means: the receiving end can perform a bit-level serial space-time-frequency TURBO encoding of the received signal on the LOG-MAP Decoding

(1) The signals received by carrier 1 and carrier 1 are respectively filtered by the receiving matched filter, and APP calculations are performed respectively.

_{Pt (u k; 0) =} p (u = u k I Ϋ Χ Ν) = AΣΣ) β Μ (σ, +1) γ [(σ,, σ Α + Ι,), the calculated code. Spatio-temporally coded codeword ^ ^);, the last rate of _c symbol level, and then use the formula (10):

P (s _i \ Y) = f [P (b ₍ IY), convert it to the bit-level likelihood ratio 'to get the full post ¾ ^

1 = 1

Likelihood ratio iT (W); O), W)); O), _ / = ι, · '· Α' At the initial iteration, let; ^) (; /) = ο, O (2) "/) = 0;

(2) Then use the formula:

Calculate side information O '); O), ^{2) e} (% (y); C);

(3) The two side information of the calculated inner code are 0 _£ /); O), ^ (u _k U); 0) deinterleaving as the outer code ^). , ^). A priori information, _k (c ^ ° (j); I), where the superscript "0" indicates a foreign code;

(4) Utilization formula: ( _{c / t} ; J) = _c ·) When calculating the posterior likelihood information of the outer code, it is always zero; l _t (; /), (u _k ; I), Brought into the formula λ ^Λ Μ]; 0) = max [ _k (a _k ) + β _Μ (σ _Μ ) + _k (u _k ; I) + _k (c _k (σ,); /)]

―,

σ _Α : ¾〇) (σ _λ .) = n0 [^ () +) + + X _k (c _k (a _k ); /)], we get ^ ( _C (); O), 7 = 1,- , « ₀ ; then bring into the formula:

(c (j); 0) = λ \ (c (j); 0) _-k (c _k (j); I), we can get ¾ (φ ·); 0), j = l,-, n ₀ ; use to convert the likelihood ratio of side information to the posterior probability of the symbol

(5) First perform serial-to-parallel conversion on ( _C ; O) to obtain 0 _A ; O) ,;) ^e (; O), respectively, to obtain the interleaved information as the a priori of the space-time-frequency coding of the inner code through interleaving. letter

;

(6) Repeat the 5 steps described above in subsequent iterations;

(7) At the last iteration, output the outer code of o /); O), j = i,-, k ₀ , use the following method to make a decision:

Then return to 1, and decode the next frame.

8. The method according to claim 3, wherein the decoding of the received signal by the receiving end means that the receiving end can perform symbol-level serial space-time frequency TURB0 on the received signal. Encoded LOG-MAP decoding;

At this time, all the probability information is expressed by the posterior probability at the symbol level, but the bit-likelihood ratio is not used. Using the formula: = _Λ (^; /), the inner code space-time is calculated.

, P ^{) e} {u, -0), no need to calculate the likelihood information at this time, but use the de-interleaving as the prior information of the outer code decoder

Λ (). ;),

When decoding in outer code:

¾ ₊ 1 (σ _{Α + Ι} ) = max (a _k (a _k ) + p _k (u _k ; I) + p _k (c _k (a _k ); /)

.

k () = ma (¾ ₊₁ (a _k ) + p _k (u _k ; J) + p _k (c _{/ c} (a _k ); I) price, ^σ Μ, Λ) ^{= h} Pk i ^c ') Pk ( ^M ;)

The calculated posterior probability of the full information is:

Pt (c; 0) = max [a _k (a _k ) + β _Μ (σ _Μ ) + p _k (u _k ; I) + p _k (c _k (a _k ); /)]-· ¾ ^χ , _n [) + ¾ ₊ i (<^ M) + Pk ( ^U k ') + Pk ( ^C k (^ k); I) pl (c; 0) = p (c; 0)-p _k (c; I), where in the iteration of the outer code ^; /) is always zero; Pt ( _k ; O) is serial-parallel converted and interleaved as the prior information P? (U _k -I),

, Iterative process after.

9. A spatio-temporal frequency TURB0 encoding device, wherein: the transmitting end includes at least a spatio-temporal TRELLIS encoder and an interleaver, and the spatio-temporal TRELLIS encoder and the interleaver form a cascaded spatio-temporal TRELLIS encoding device; during encoding: input bits are input respectively Space-time TRELLIS encoder and interleaver, and output after encoding;

The receiving end includes at least a time-space-frequency decoding device based on LOG-MAP decoding.

10. The device according to claim 9, wherein the cascaded time TRELLIS encoding device is: a time-space TRELLIS encoding device cascaded in parallel, which is composed of a time TRELLIS encoder, an interleaver, and a modulation. Antenna and antenna;

During encoding: The input bits are input into the space-time TRELLIS encoder and interleaver respectively. The bits of the input space-time TRELLIS encoder are encoded and output to the modulator, and the signal output by the modulator is sent by the antenna. After the bits of the input interleaver are interleaved, another input is required. The space-time TRELLIS encoder is encoded and output to another modulator, and the signal output by the modulator is sent through another antenna.

11. The device according to claim 9, characterized in that, when The TRELLIS coding device refers to: a serially cascaded space-time TRELLIS coding device, which is composed of a space-time TRELLIS encoder, an interleaver, a modulator, and an antenna;

When encoding: the input bits are first input to the space-time TRELLIS encoder, and the output of the space-time TRELLIS encoder is the input of at least two interleavers, and the output of the interleaver is the input of at least two other space-time TRELLIS encoders, the at least two The output of each space-time TRELLIS encoder is the input of at least two modulators, and the signals output by the at least two modulators are respectively sent through at least two antennas.

12. The device according to claim 9, wherein the cascaded spatio-temporal TRELLIS coding device refers to: a spatio-temporal TRELLIS coding device capable of transmitting a parallel cascade of one information symbol and three calibration symbols. , Which is composed of space-time TRELLIS encoder, interleaver, modulator, and antenna;

During encoding: The input bits are input to a space-time TRELLIS encoder and an interleaver respectively. The bits of the input space-time TRELLIS encoder are encoded and output to a modulator, and the signal output by the modulator is sent through an antenna;

After the bits of the input interleaver are interleaved, the second space-time TRELLIS encoder and the second interleaver must be input respectively. The output of the second interleaver is the input of the three space-time TRELLIS encoders, and the output of the second space-time TRELLIS encoder is The output and the output of the third space-time TRELLIS encoder are the input of the second modulator, and the signal output by the second modulator is sent by the second antenna.

13. The device according to claim 10 or 12, characterized in that the decoding device is a single-rate parallel space-time-frequency TURBO decoder; and it comprises a matched filter, an APP calculator, an interleaver, and deinterleaving. Device and discrimination device structure;

During decoding: The signals received by carrier 1 and carrier 2 respectively pass through the receiving matched filters 1 and 2 and enter the two APP calculators. The decoding is completed by iterative decoding based on the LOG-MAP decoding algorithm.

14. The device according to claim 11, wherein the decoding device is a serial space-time-frequency TURBO decoder; it is determined by a matched filter, an APP calculator, an interleaver, a deinterleaver, Device composition

During decoding: The signals received by carrier 1 and carrier 2 respectively pass through the receiving matched filters 1 and 2 and enter the two APP calculators. The outputs of the two APP calculators are the inputs of deinterleavers 1 and 2, respectively. The outputs of the de-interlacers 1 and 2 together become the input of the third APP calculator, and the decoding is completed by iterative decoding based on the LOG-MAP decoding algorithm.