CN104022993B - SLM method for lowering peak-to-average power ratio of SFBC MIMO-OFDM system - Google Patents

Abstract

The invention discloses an SLM method for lowering the peak-to-average power ratio of an SFBC MIMO-OFDM system. Information source bits of each antenna pass through a baseband modulation unit and a series-parallel-connection conversion unit, are subjected to different phase rotation, and then are subjected to IFFT modulation to obtain time domain signals, time domain odd-even signals are obtained through the circulation shift property of time domain signals of an FFT, and the time domain odd-even signals are subjected to different lengths of time domain circulation shifts and then subjected to time domain equivalent SFBC encoding to obtain alternative sequence pairs with different PAPRs. On the basis of a traditional SLM algorithm, more alternative sequence sets with different PAPRs can be obtained only through circulation shift and phase rotation of the time domain signals, and the PAPR inhibition performance is improved. Meanwhile, a receiving end recovers the odd-even signals, circulation shift factors and phase rotation factors by comparing the distance between a reverse rotation sequence and a nearest signal constellation point, and sideband secondary information does not need to be transmitted.

Description

A kind of SLM methods of reduction SFBC MIMO-OFDM system peak-to-average power ratios

Technical field

The invention belongs to wireless communication technology field, more particularly to a kind of to reduce SFBC MIMO-OFDM system peak-to-average power The SLM methods of ratio.

Background technology

It is well known that multi-I/O OFDM (abbreviation MIMO-OFDM) system is by using frequency, time And diversity gain is obtained using different antennae, and multipath, noise in radio communication etc. can be effectively resisted, become following shifting One of major candidate of dynamic multimedia communication.

MIMO-OFDM signals are a kind of multicarrier modulated signals, and one of major defect is signal peak power and average work( The ratio (abbreviation PAPR) of rate is higher.A kind of main stream approach of space frequency block coding (SFBC) MIMO-OFDM systems is reduced at present It is selected mapping method method (referred to as SLM methods).Without loss of generality, two transmitting antenna SFBCMIMO- described below Ofdm system.The transmitting terminal principle of traditional SLM methods as shown in figure 1, receiving terminal principle as shown in Fig. 2 every antenna it is original Ofdm signal is multiplied with the rotatable phase sequence that U modulus value is 1, the output signal of U expression identical information is obtained, then by this U signal carries out respectively SFBC and obtains two paths of signals, and this two paths of signals carries out IFFT and modulates accordingly as a sequence pair Time-domain alternative signals, calculate respectively the PAPR of each alternative sequence and select larger one as the PAPR of this sequence pair, A minima is selected in the PAPR of all of sequence pair as the PAPR of whole SFBC MIMO-OFDM systems, this sequence pair As transmission signal.In order to be demodulated in order to correctly dock the collection of letters number in receiving terminal, institute must be sent in transmitting terminal The secondary information of this sideband of the phase factor for using.In SFBC MIMO-OFDM systems, a deficiency of traditional SLM methods is, In order to obtain reasonable PAPR rejections, it usually needs select the minimum sequence pairs of a PAPR from multiple alternative centerings Transmission, and each alternative signal is obtained to being required for being modulated by IFFT, the computation complexity of algorithm is higher.Traditional SLM methods Another deficiency is that, in order that system can recover primary signal in receiving terminal, transmitting terminal needs what transmission was used The secondary information of this sideband of phase factor, the transmission of sideband pair information reduces the spectrum utilization efficiency of system.

The content of the invention

It is an object of the invention to overcome the deficiencies in the prior art, there is provided a kind of IFFT computings in traditional SLM algorithms Under several, the operation such as cyclic shift and phase place of time-domain signal is only needed to can be obtained by multiple sequence sets with different PAPR Close, receiving terminal recovers parity signal and circulation by comparing the distance for reversely rotating sequence and its nearest signal constellation point Translocation factor and phase rotation coefficient, greatly reduce the reduction SFBC MIMO-OFDM system peak-to-average work(of system-computed complexity The SLM methods of rate ratio.

The purpose of the present invention is realized by technical scheme once：One kind reduces SFBC MIMO-OFDM system peak-to-averages The SLM methods of power ratio, including transmitting processing procedure and reception processing process two parts, described transmitting processing procedure specifically flows Cheng Wei：

S101：The source bits of every antenna obtain original frequency domain letter after baseband modulation unit and serioparallel exchange unit Number X, original frequency domain signal X carry out carrying out IFFT modulation after different phase places into phase place sequencer, i.e., former Beginning frequency domain signal X and phase rotation coefficient P^vV corresponding time-domain signal x is obtained by IFFT modulating units after multiplication^v, wherein, 1≤v≤V, V represent phase rotation coefficient number；

S102：For time-domain signal x^v, using the time-domain signal cyclic shift property of FFT, i.e. F [x (n), k]=x (n-k)_N <=>F [X (n), k]=X (n) e^-j2πkn/N, the corresponding time domain parity signal of frequency domain sequence of parity is obtained, wherein, ()_NRepresent Mould N is operated, and selects k=N/2 so that the sequence of parity of frequency domain produces different phase place changes：

Learnt by both the above formula, the sequence of parity of frequency-region signal can be distinguished using the cyclic shift of time-domain signal Come, therefore, by time-domain signal x^vCan be respectively in the hope of time domain parity signal with the signal after its cyclic shift：

S103：To obtaining the strange signal of time domainWith time domain idol signalMoved using the time domain cyclic for carrying out different length respectively Carry out time-domain equivalent SFBC coding again behind position, each time-domain cyclic shift and carry out time-domain equivalent SFBC coding obtain one it is alternative Sequence pair, described time-domain equivalent SFBC coded method is：Inverted corresponding to frequency-region signal using the conjugation of the time-domain signal of FFT Conjugation fundamental property, i.e. FFT [x ((N-n) N)^*X]=[(n)]^*, the strange signal of each time domainWith time domain idol signalPoint Be not circulated displacement after carry out again be conjugated reversion obtain corresponding encoded signal, the SFBC coding forms of frequency-region signal are represented For：

If the strange signal of time domainWith time domain idol signalThe cyclic shift factor be respectively： With M represents the number of times of cyclic shift, obtains M kinds by time-domain cyclic shift operation different Time-domain signal sequence：

In above formula, 1≤m, n≤M；Time domain parity signal is entered again after the time-domain cyclic shift respectively through M different length Row time-domain equivalent SFBC is encoded, and M is always obtained²Different alternative sequences pair are planted, because the cyclic shift of time-domain signal is corresponded to The phase place of frequency-region signal, then its frequency-region signal SFBC coding forms be collectively expressed as：

The corresponding time domain parity signal of V time-domain signal after time-domain cyclic shift operation again respectively through carrying out time-domain equivalent SFBC is encoded, and VM is always obtained²Plant alternative sequence pair；

S104：The PAPR of each alternative sequence pair is calculated, a PAPR as whole sequence pair for selecting PAPR maximum, Then PAPR minima is selected in all of sequence pair as the PAPR of system, and selects PAPR minimum a pair of sequences to conduct Transmission sequence, the transmission sequence enters cyclic prefix unit after parallel serial conversion unit and adds Cyclic Prefix, then turns through D/A Change and launched by antenna after unit and radio frequency unit；

Described reception processing process idiographic flow is：

S201：The reception signal of antenna passes sequentially through radio frequency unit, A/D converting units, removes cyclic prefix unit and string simultaneously FFT demodulation is carried out after converting unit and obtains frequency-region signal R=[R_e, R_o], the form for receiving signal is represented：

In formula, H_ieAnd H_ioTransmission channel gain, N are represented respectively_iInterchannel noise is represented, wherein, i=1,2, for adjacent The channel gain of sub-carrier signal, there is H_1e=H_1o=H₁, H_2e=H_2o=H₂, therefore to frequency-region signal R=[R_e, R_o] carry out SFBC Decoding, obtains signal [Y_e, Y_o]：

In formula, α²=| H₁|²+|H₂|², [the Y for solving_e, Y_o] it is by transmitting terminal time domain parity signalHave passed through not Be the equal of that the signal that phase place is obtained has been carried out by frequency-region signal with the signal after the cyclic shift of length；

S202：The frequency domain parity signal that SFBC decodings are obtained is carried out into signal blind Detecting：To the signal [Y for solving_e, Y_o] enter Row reverse phase rotates, and recovers the cyclic shift factor and phase rotation coefficient P^v, recovery is multiplied by by the reverse rotation sequence for obtaining The phase rotation coefficient P for going out^vDetection signal is obtained, the detection signal to obtaining carries out parallel-serial conversion and base band demodulating recovers to obtain Primary signal.

The signal blind Detecting of described step S202 includes recovering the cyclic shift factor and recovery phase rotation coefficient two Point, the method for the described recovery cyclic shift factor is：

To the signal [Y for solving_e, Y_o] reverse phase rotation is carried out, due to the time domain parity signal of transmitting terminalRespectively From having used the VM cyclic shift factor, therefore, parity signal Y_eAnd Y_oIt is respectively necessary for VM complex multiplication and realizes that reverse phase is revolved Turn：

In formula, 1≤v≤V, 1≤m≤M, 1≤vm≤VM,By upper Formula, parity signal respectively obtains VM reverse rotation sequence, and these reversely rotate in sequence and there will necessarily be a sequence, its institute There is frequency to have rotated in the constellation point of modulated signal, because noise is present, frequency may deviate from original constellation point, but All frequency its nearest neighbours constellation points from probability are minimum apart from sum, therefore, first reverse rotation sequenceWithIt is judged to from its nearest constellation point Y^Q(n), then all frequencies are calculated to constellation point Y^QThe distance of (n) it VM distance value has been respectively obtained with, the strange signal of time domain and time domain idol signal, a most narrow spacing has been selected respectively from all distances From the corresponding cyclic shift factorWithTransmitting terminal time domain parity signal the mostWithThe cyclic shift factor, be designated as u′_eWith u '_o：

In above formula, Y^Q(n) ∈ Q, Q for transmitting terminal selected modulation mode signal constellation (in digital modulation) figure, the cyclic shift for recovering because Sub- u '_eWith u '_oCorresponding reverse rotation signalWithRespectively as the strange signal for recovering to obtain and even signal；

Described recovery phase rotation coefficient P^vMethod be：Due to original frequency domain signal X be multiplied by every time phase place because Sub- P^vAfter carry out IFFT modulation time-domain signal x^vSequence of parityWithThe cyclic shift factor for usingWithDifference, because This, by the cyclic shift factor u ' for obtaining_eWith u '_oThe vector at place is judging to obtain the phase rotation coefficient that transmitting terminal is used P^v。

The invention has the beneficial effects as follows：Primary signal carries out respectively IFFT modulation when obtaining after different phase places Domain signal, then obtains the corresponding time-domain signal sequence of frequency domain sequence of parity using the property of IFFT, and sequence of parity carries out difference Carry out after the cyclic shift of length time-domain equivalent SFBC coding obtain multiple alternative sequences pair with different PAPR, finally from The sequence pair for selecting PAPR performances best in all of alternative sequence is transmitted.Therefore, in the IFFT computings of traditional SLM algorithms Under number, the operation such as cyclic shift and phase place of time-domain signal is only needed to can be obtained by multiple sequences with different PAPR Set, greatly reduces system-computed complexity；Receiving terminal reversely rotates sequence with its nearest signal constellation point by comparing Distance realizes the blind Detecting for receiving signal recovering parity signal and the cyclic shift factor and phase rotation coefficient, passes The SLM methods of system are compared, and computation complexity is substantially reduced, and need not transmit sideband pair information.

Description of the drawings

Fig. 1 is the transmitting terminal block diagram of traditional SLM algorithms；

Fig. 2 is the receiving terminal block diagram of traditional SLM algorithms；

Fig. 3 is the transmitting process flowchart of the improvement SLM algorithms of the present invention；

Fig. 4 is the flow chart of time-domain cyclic shift and time-domain equivalent SFBC coding in present invention transmitting processing procedure；

Fig. 5 is the equivalent SFBC coding principles figure of the present invention；

Fig. 6 is the reception processing process flow diagram flow chart of the improvement SLM algorithms of the present invention；

Fig. 7 is the flow chart of signal blind Detecting during reception processing of the invention.

Specific embodiment

Further illustrate technical scheme below in conjunction with the accompanying drawings, but the content protected of the present invention be not limited to It is lower described.

A kind of SLM methods of reduction SFBC MIMO-OFDM system peak-to-average power ratios, including transmitting processing procedure and reception Processing procedure two parts, as shown in figure 3, described transmitting processing procedure idiographic flow is：

S101：The source bits of every antenna obtain original frequency domain letter after baseband modulation unit and serioparallel exchange unit Number X, original frequency domain signal X carry out carrying out IFFT modulation after different phase places into phase place sequencer, i.e., former Beginning frequency domain signal X and phase rotation coefficient P^vV corresponding time-domain signal x is obtained by IFFT modulating units after multiplication^v, wherein, 1≤v≤V, V represent phase rotation coefficient number；

S102：For time-domain signal x^v, using the time-domain signal cyclic shift property of FFT, i.e. F [x (n), k]=x (n-k)_N <=>F [X (n), k]=X (n) e^-j2πkn/N, the corresponding time domain parity signal of frequency domain sequence of parity is obtained, wherein, ()_NRepresent Mould N is operated, and selects k=N/2 so that the sequence of parity of frequency domain produces different phase place changes：

Learnt by both the above formula, the sequence of parity of frequency-region signal can be distinguished using the cyclic shift of time-domain signal Come, therefore, by time-domain signal x^vCan be respectively in the hope of time domain parity signal with the signal after its cyclic shift：

S103：To obtaining the strange signal of time domainWith time domain idol signalMoved using the time domain cyclic for carrying out different length respectively Carry out time-domain equivalent SFBC coding again behind position, each time-domain cyclic shift and carry out time-domain equivalent SFBC coding obtain one it is alternative Sequence pair, as shown in figure 4, described time-domain equivalent SFBC coded method is as shown in figure 5, the conjugation of the time-domain signal using FFT Invert the fundamental property of the conjugation corresponding to frequency-region signal, i.e. FFT [x ((N-n) N)^*X]=[(n)]^*, the strange signal of each time domainWith time domain idol signalBe circulated respectively displacement after carry out again be conjugated reversion obtain corresponding encoded signal, frequency-region signal SFBC coding forms be expressed as：

If the strange signal of time domainWith time domain idol signalThe cyclic shift factor be respectively：With M represents the number of times of cyclic shift, by time-domain cyclic shift operation obtain M kinds it is different when Domain signal sequence：

In above formula, 1≤m, n≤M；Time domain parity signal is entered again after the time-domain cyclic shift respectively through M different length Row time-domain equivalent SFBC is encoded, and M is always obtained²Different alternative sequences pair are planted, because the cyclic shift of time-domain signal is corresponded to The phase place of frequency-region signal, then its frequency-region signal SFBC coding forms be collectively expressed as：

The corresponding time domain parity signal of V time-domain signal after time-domain cyclic shift operation again respectively through carrying out time-domain equivalent SFBC is encoded, and VM is always obtained²Plant alternative sequence pair；

S104：The PAPR of each alternative sequence pair is calculated, a PAPR as whole sequence pair for selecting PAPR maximum, Then PAPR minima is selected in all of sequence pair as the PAPR of system, and selects PAPR minimum a pair of sequences to conduct Transmission sequence, is designated as [x '₁, x '₂,], the transmission sequence enters cyclic prefix unit after parallel serial conversion unit and adds before circulation Sew, then launched by antenna after D/A converting units and radio frequency unit；

As shown in fig. 6, described reception processing process idiographic flow is：

S201：The reception signal of antenna passes sequentially through radio frequency unit, A/D converting units, removes cyclic prefix unit and string simultaneously FFT demodulation is carried out after converting unit and obtains frequency-region signal R=[R_e, R_o], the form for receiving signal is represented：

In formula, H_ieAnd H_ioTransmission channel gain, N are represented respectively_iInterchannel noise is represented, wherein, i=1,2, for adjacent The channel gain of sub-carrier signal, there is H_1e=H_1o=H₁, H_2e=H_2o=H₂, therefore to frequency-region signal R=[R_e, R_o] carry out SFBC Decoding, obtains signal [Y_e, Y_o]：

In formula, α²=| H₁|²+|H₂|², [the Y for solving_e, Y_o] it is by transmitting terminal time domain parity signalHave passed through not Be the equal of that the signal that phase place is obtained has been carried out by frequency-region signal with the signal after the cyclic shift of length；

S202：The frequency domain parity signal that SFBC decodings are obtained is carried out into signal blind Detecting：To the signal [Y for solving_e, Y_o] enter Row reverse phase rotates, and recovers the cyclic shift factor and phase rotation coefficient P^v, recovery is multiplied by by the reverse rotation sequence for obtaining The phase rotation coefficient P for going out^vDetection signal is obtained, the detection signal to obtaining carries out parallel-serial conversion and base band demodulating recovers to obtain Primary signal.

As shown in fig. 7, the signal blind Detecting of described step S202 includes recovering the cyclic shift factor and recovery phase place rotation Transposon two parts, the method for the described recovery cyclic shift factor is：

To the signal [Y for solving_e, Y_o] reverse phase rotation is carried out, due to the time domain parity signal of transmitting terminalRespectively From having used the VM cyclic shift factor, therefore, parity signal Y_eAnd Y_oIt is respectively necessary for VM complex multiplication and realizes that reverse phase is revolved Turn：

In formula, 1≤v≤V, 1≤m≤M, 1≤vm≤VM,Pass through Above formula, parity signal respectively obtains VM reverse rotation sequence, and these reversely rotate in sequence and there will necessarily be a sequence, it All frequencies have been had rotated in the constellation point of modulated signal, and because noise is present, frequency may deviate from original constellation point, But all frequency its nearest neighbours constellation points from probability are minimum apart from sum, therefore, first reverse rotation sequenceWithIt is judged to from its nearest constellation point Y^Q(n), then all frequencies are calculated to constellation point Y^QThe distance of (n) it VM distance value has been respectively obtained with, the strange signal of time domain and time domain idol signal, a most narrow spacing has been selected respectively from all distances From the corresponding cyclic shift factorWithTransmitting terminal time domain parity signal the mostWithThe cyclic shift factor, be designated as u′_eWith u '_o：

In above formula, Y^Q(n) ∈ Q, Q for transmitting terminal selected modulation mode signal constellation (in digital modulation) figure, the cyclic shift for recovering because Sub- u '_eWith u '_oCorresponding reverse rotation signalWithRespectively as the strange signal for recovering to obtain and even signal；

Described recovery phase rotation coefficient P^vMethod be：Due to original frequency domain signal X be multiplied by every time phase place because Sub- P^vAfter carry out IFFT modulation time-domain signal x^vSequence of parityWithThe cyclic shift factor for usingWithDifference, because This, by the cyclic shift factor u ' for obtaining_eWith u '_oThe vector at place is judging to obtain the phase rotation coefficient that transmitting terminal is used P^v, for example, if, then judge phase rotation coefficient that X uses for P¹。

When the sub-carrier number of OFDM is N, when over-sampling rate is L, complex multiplication number of times that an IFFT computing needs and multiple Number addition number of times is respectively LN/2log₂LN and LNlog₂LN.When the number of the alternative sequence pair for producing is VM²When, can by Fig. 1 Know, traditional SLM algorithms need 2VM²Frequency domain sequence modulation after the IFFT computings of secondary LN points encode SFBC obtains VM²It is individual Time domain alternative sequence pair, required complex multiplication number of times and complex addition number of times is respectively VM²LN/2log₂LN and 2VM²LN log₂LN.Algorithm proposed by the present invention, equally produces VM²Individual alternative sequence pair, original frequency domain signal needs only to V LN point IFFT computings obtain time-domain signal, and required complex multiplication number of times and complex addition number of times is respectively VLN/2log₂LN and VLN log₂LN, operates in cyclic shift, conjugation reversion and time domain phase place that different length is carried out to time domain parity signal etc. To multiple alternative sequences pair, the complex multiplication number of times and complex addition number of times of needs are respectively 2VMLN and 2VM²LN, therefore, this The algorithm of invention complex multiplication altogether and complex addition number of times are respectively VLN (1/2 log₂) and VLN (log LN+2M₂LN+ 2M²)。

In order to weigh the reduction performance of computation complexity, generally using computation complexity reduces than (computational Complexity reduction ratio, CCRR), it is defined as：

In formula, CSB-SLM represents the algorithm of the present invention, and C-SLM represents traditional algorithm.Following table gives works as sub-carrier number N=256, over-sampling rate L=4, C-SLM algorithms and CSB-SLM algorithms are all K=VM when the number of the alternative sequence pair for producing² When, required complex multiplication and plural number adds number of times and CCRR functional values.

The computation complexity of the transmitting terminal of table 1

As shown in Table 1, when identical alternative sequence number is produced, CSB-SLM algorithms can be greatly lowered C-SLM algorithms Computation complexity, when alternative sequence number is 12, the complex multiplication and complex addition number of times of CSB-SLM needs is relative to C-SLM Algorithm, CCRR has respectively reached 77.5% and 77.5%.It should be noted that with the increase of alternative sequence number, it is of the invention Algorithm reduces the ability of complexity and also will be further increased, therefore, CSB-SLM algorithms are carried herein to be had in terms of complexity is reduced Larger advantage.

When the time domain alternative sequence number that transmitting terminal is produced is VM²When, traditional SLM algorithms transmitting terminal needs transmission to be used Phase rotation coefficient P this sideband pair information, log is needed altogether₂VM²Bit, algorithm proposed by the present invention, if translocation factor U With phase rotation coefficient P equally as sideband pair information transfer, log is needed also exist for₂VM²Bit.For traditional SLM algorithms, receive The FFT computings of LN point of signal demand obtain frequency-region signal, then according to the side information for receiving, frequency-region signal is direct Be multiplied by corresponding phase rotation coefficient to recover to obtain primary signal, accordingly, it would be desirable to complex multiplication number of times and complex addition number of times Respectively LN/2log₂LN+2N and LN log₂LN.SLM algorithms proposed by the present invention, receive signal and need also exist for LN point FFT computings obtain frequency-region signal and decode it to obtain frequency domain sequence of parity, if U and P, it is known that if the direct basis of sequence of parityWithObtain reversely rotating signal, Ran Houzai It is multiplied by phase rotation coefficient and obtains primary signal, at this moment, the complexity of receiving terminal is suitable with tradition SLM algorithms；If U and P are unknown, 2MV N points complex multiplication is then needed to realize reversely rotating sequence with the Distance Judgment of corresponding modulated signal constellation point to recover Translocation factor is recycled, therefore, the complex multiplication number of times that SLM algorithms receiving terminal proposed by the present invention needs altogether adds with plural number to be sent out Number of times is respectively LN/2log₂LN+2MVN (L+1) and LNlog₂LN+2MVN。

Claims (2)

1. a kind of SLM methods of reduction SFBC MIMO-OFDM system peak-to-average power ratios, including transmitting processing procedure and receiving area Reason process two parts, it is characterised in that：Described transmitting processing procedure idiographic flow is：

S101：The source bits of every antenna obtain original frequency domain signal X after baseband modulation unit and serioparallel exchange unit, Original frequency domain signal X carries out carrying out IFFT modulation after different phase places into phase place sequencer, i.e., original frequency Domain signal X and phase rotation coefficient P^vV corresponding time-domain signal x is obtained by IFFT modulating units after multiplication^v, wherein, 1≤v ≤ V, V represent phase rotation coefficient number；

S102：For time-domain signal x^v, using the time-domain signal cyclic shift property of FFT, i.e. F [x (n), k]=x (n-k)_N<=> F [X (n), k]=X (n) e^-j2πkn/N, the corresponding time domain parity signal of frequency domain sequence of parity is obtained, wherein, ()_NRepresent mould N Operation, selects k=N/2 so that the sequence of parity of frequency domain produces different phase place changes：

Learnt by both the above formula, the sequence of parity of frequency-region signal can be distinguished using the cyclic shift of time-domain signal Come, therefore, by time-domain signal x^vCan be respectively in the hope of time domain parity signal with the signal after its cyclic shift：

$x_e^v=(x^v+F\&lsqb;x^v,N/2\&rsqb;)/2$

$x_o^v=(x^v-F\&lsqb;x^v,N/2\&rsqb;)/2;$

S103：To obtaining the strange signal of time domainWith time domain idol signalUsing after the time-domain cyclic shift for carrying out different length respectively Carry out time-domain equivalent SFBC coding again, each time-domain cyclic shift simultaneously carries out time-domain equivalent SFBC coding and obtains an alternative sequence Right, described time-domain equivalent SFBC coded method is：Using conjugation reversion being total to corresponding to frequency-region signal of the time-domain signal of FFT The fundamental property of yoke, i.e. FFT [x ((N-n)_N)^*X]=[(n)]^*, the strange signal of each time domainWith time domain idol signalCarry out respectively Carry out conjugation reversion after cyclic shift again and obtain corresponding encoded signal, the SFBC coding forms of frequency-region signal are expressed as：

$\left[\begin{array}{cc}{X}_e^v\left(n\right)& -{\&lsqb;X_o^v\left(n\right)\&rsqb;}^{*}\\ X_o^v\left(n\right)& {\&lsqb;X_e^v\left(n\right)\&rsqb;}^{*}\end{array}\right]$

If the strange signal of time domainWith time domain idol signalThe cyclic shift factor be respectively：WithM represents the number of times of cyclic shift, by time-domain cyclic shift operation obtain M kinds it is different when Domain signal sequence：

$x_e^{vm}=circshift\{x_e^v,\&lsqb;0,u_e^{vm}\&rsqb;\}$

$x_o^{vn}=circshift\{x_o^v,\&lsqb;0,u_o^{vn}\&rsqb;\}$

In above formula, 1≤m≤M, 1≤n≤M；Time domain parity signal respectively through after the time-domain cyclic shift of M different length again Time-domain equivalent SFBC coding is carried out, M is always obtained²Different alternative sequences pair are planted, due to the cyclic shift correspondence of time-domain signal In the phase place of frequency-region signal, then its frequency-region signal SFBC coding forms are collectively expressed as：

$\left[\begin{array}{cc}{e}^{j2{\mathrm{\&pi;u}}_e^{vm}(n-1)/N}{X}_e^{vm}\left(n\right)& -{\&lsqb;e^{j2{\mathrm{\&pi;u}}_o^{vn}(n-1)/N}{X}_o^{vn}\left(n\right)\&rsqb;}^{*}\\ e^{j2{\mathrm{\&pi;u}}_0^{vn}(n-1)/N}{X}_o^{vn}\left(n\right)& {\&lsqb;e^{j2{\mathrm{\&pi;u}}_e^{vm}(n-1)/N}{X}_o^{vm}\left(n\right)\&rsqb;}^{*}\end{array}\right]$

The corresponding time domain parity signal of V time-domain signal after time-domain cyclic shift operation again respectively through carrying out time-domain equivalent SFBC Coding, is always obtained VM²Plant alternative sequence pair；

S104：The PAPR of each alternative sequence pair is calculated, a PAPR as whole sequence pair for selecting PAPR maximum, then PAPR minima is selected in all of sequence pair as the PAPR of system, and selects PAPR minimum a pair of sequences to as transmission Sequence, the transmission sequence enters cyclic prefix unit after parallel serial conversion unit and adds Cyclic Prefix, then single through D/A conversions Launched by antenna after unit and radio frequency unit；

Described reception processing process idiographic flow is：

S201：The reception signal of antenna passes sequentially through radio frequency unit, A/D converting units, removes cyclic prefix unit and serioparallel exchange FFT demodulation is carried out after unit and obtains frequency-region signal R=[R_e, R_o], the form for receiving signal is represented：

$R_e=H_{1e}{e}^{j2{\mathrm{\&pi;u}}_e^{vm}/N}{X}_e^{vm}+H_{2e}{e}^{j2{\mathrm{\&pi;u}}_o^{vn}/N}{X}_o^{vn}+N_1$

$R_o=H_{1o}{\&lsqb;-e^{j2{\mathrm{\&pi;u}}_o^{vn}/N}{X}_o^{vn}\&rsqb;}^{*}+H_{2o}{\&lsqb;e^{j2{\mathrm{\&pi;u}}_e^{vm}/N}{X}_e^{vm}\&rsqb;}^{*}+N_2$

In formula, H_ieAnd H_ioTransmission channel gain, N are represented respectively_iInterchannel noise is represented, wherein, i=1,2, for adjacent son is carried The channel gain of ripple signal, there is H_1e=H_1o=H₁, H_2e=H_2o=H₂, therefore to frequency-region signal R=[R_e, R_o] carry out SFBC solutions Code, obtains signal [Y_e, Y_o]：

$\left\{\begin{array}{c}{Y}_e={\mathrm{\&alpha;}}^{-2}(R_e{\left(H_1\right)}^{*}+{\left(R_o\right)}^{*}{H}_2)\\ Y_o={\mathrm{\&alpha;}}^{-2}(R_e{\left(H_2\right)}^{*}-{\left(R_o\right)}^{*}{H}_1)\end{array}\right.$

In formula, α²=| H₁|²+|H₂|², [the Y for solving_e, Y_o] it is by transmitting terminal time domain parity signalHave passed through different length Cyclic shift after signal, be the equal of that the signal that phase place is obtained has been carried out by frequency-region signal；

S202：The frequency domain parity signal that SFBC decodings are obtained is carried out into signal blind Detecting：To the signal [Y for solving_e, Y_o] carry out instead To phase place, recover the cyclic shift factor and phase rotation coefficient P^v, it is multiplied by what is recovered by the reverse rotation sequence for obtaining Phase rotation coefficient P^vDetection signal is obtained, the detection signal to obtaining carries out parallel-serial conversion and base band demodulating recovers to obtain original Signal.

2. SLM methods of reduction SFBC MIMO-OFDM system peak-to-average power ratios according to claim 1, its feature exists In：The signal blind Detecting of described step S202 includes recovering the cyclic shift factor and recovery phase rotation coefficient two parts, institute The method of the recovery cyclic shift factor stated is：

To the signal [Y for solving_e, Y_o] reverse phase rotation is carried out, due to the time domain parity signal of transmitting terminalEach use VM cyclic shift factor, therefore, parity signal Y_eAnd Y_oIt is respectively necessary for VM complex multiplication and realizes that reverse phase rotates：

$Y_e^{vm}\left(n\right)=y_e\left(n\right)e^{j2{\mathrm{\&pi;u}}_e^{vm}(n-1)/N}$

$Y_o^{vm}\left(n\right)=Y_o\left(n\right)e^{j2{\mathrm{\&pi;u}}_o^{vm}(n-1)/N}$

In formula, 1≤v≤V, 1≤m≤M, 1≤vm≤VM,It is logical Above formula is crossed, parity signal respectively obtains VM reverse rotation sequence, and these reversely rotate in sequence and there will necessarily be a sequence, it All frequencies had rotated in the constellation point of modulated signal, because noise is present, frequency may deviate from original constellation Point, but all frequency its nearest neighbours constellation points from probability is minimum apart from sum, therefore, first reverse rotation sequenceWithIt is judged to from its nearest constellation point Y^Q(n), then all frequencies are calculated to constellation point Y^QThe distance of (n) it VM distance value has been respectively obtained with, the strange signal of time domain and time domain idol signal, a most narrow spacing has been selected respectively from all distances From the corresponding cyclic shift factorWithTransmitting terminal time domain parity signal the mostWithThe cyclic shift factor, be designated as u′_eWith u '_o：

$u_e^{\&prime;}=\arg \underset{1\&le;vm\&le;VM}{min}\underset{n=1}{\overset{N}{\&Sigma;}}|Y_e^{vm}\left(n\right)-Y^Q\left(n\right){|}^2$

$u_o^{\&prime;}=\arg \underset{1\&le;vm\&le;VM}{min}\underset{n=1}{\overset{N}{\&Sigma;}}|Y_o^{vm}\left(n\right)-Y^Q\left(n\right){|}^2$

In above formula, Y^Q(n) ∈ Q, Q for transmitting terminal selected modulation mode signal constellation (in digital modulation) figure, the cyclic shift factor u ' for recovering_e With u '_oCorresponding reverse rotation signalWithRespectively as the strange signal for recovering to obtain and even signal；

Described recovery phase rotation coefficient P^vMethod be：Because original frequency domain signal X is multiplied by every time phase rotation coefficient P^vAfterwards Carry out IFFT modulation time-domain signal x^vSequence of parityWithThe cyclic shift factor for usingWithDifference, therefore, pass through The cyclic shift factor u ' for obtaining_eWith u '_oThe vector at place is judging to obtain the phase rotation coefficient P that transmitting terminal is used^v。