CN105007578A - Uplink secure transmission method based on downlink auxiliary feedback in 5G communication system - Google Patents

Abstract

The invention discloses an uplink secure transmission method based on downlink auxiliary feedback in a 5G communication system. In the first stage, a multi-antenna base station end sends both artificial interference and artificial noise signals on a downlink by means of a wave beam formation technology; and a single-antenna user end receives an emission signal from the base station end, and scrambles the received signal to a to-be-sent secret signal so that a mixed emission signal is formed. In the second stage, the user terminal broadcasts the mixed emission signal; and the base station end receives the mixed emission signal. Since the base station end already knows an artificial interference signal emitted by the base station itself, an expected secret signal can be separated from the received signal. A single-antenna passive eavesdropping end receives mixed signals during both transmission stages, and cannot know any prior information about the artificial interference and artificial noise signals, so the possibility of stealing secret information is low. Therefore, the transmission security of a 5G uplink single-input and multi-output system is effectively guaranteed.

Description

Based on the up safe transmission method that downstream feedback is auxiliary in 5G communication system

Technical field

The present invention relates to a kind of safe transmission method of wireless communication system, particularly relate to a kind of safe transmission method for the up single input and multi-output of the 5G under TDD mode (SIMO) wireless communication system.

Background technology

Wireless communication technology, while offering convenience for the daily production of people, life, also inevitably because of the unboundedness of its physical transfer, brings the puzzlement that Content of Communication is easy to stolen to communicating pair.Along with the intensification day by day of wireless communication technology development degree and popularity, the safety problem of communication is also taken seriously further.Adopt which kind of means effectively take precautions against information leakage, guarantee that the safe transmission of information will become a long-term focus Journal of Sex Research problem.

As the key technology of a most prospect in 5G radio communication, extensive multiple-input and multiple-output (MassiveMultiple-Input Multiple-Output, Massive MIMO) technology has been subject to paying close attention to more and more widely from academia and industrial quarters.Under this technical background, 5G system base-station end is configured extensive antenna array, thus the transmission of the safety of physical layer of 5G downlink communication can obtain effective guarantee, and correlative study achievement also emerged in multitude in nearly 5 years.But the transmitting power limited due to user side and transmit antenna number, rare document can provide effective technological means to ensure the fail safe of 5G uplink.

Existing radio physical layer secure transmission technique roughly has cipher key technique and the large class of multi-antenna technology two.Cipher key technique aspect, in being entitled as in the document of " Feedback-basedcollaborative secrecy encoding over binary symmetric channels " that IEEE Transactions on Information Theory delivers in August, 2012, proposing a kind of system safety performance based on key feedback and strengthen strategy.Although this strategy make use of the key that destination feeds back to source, and effectively ensure that the fail safe that source secret signal is transmitted, the communication system of single antenna node composition can only be served, and only limited security performance can be brought to promote for system.In the large class of multi-antenna technology, the anti-eavesdrop technology that man made noise assists is again the branch of an outbalance.In being entitled as in the document of " Secure transmission with artificial noise over fading channels:Achievable rate andoptimal power allocation " that IEEE Transactions on Vehicular Technology delivers in October, 2010, propose a kind of system safety transmission policy injected based on man made noise's optimal power.Although this strategy is on the basis completing optimal power proportioning between secret signal and man made noise's signal, the maximization that can reach safe rate to system can be realized, but the SIMO wireless communication system be made up of single antenna source and multiple antennas destination can not be served.

Summary of the invention

The object of the invention is to for the up single input and multi-output of the 5G under TDD mode (SIMO) wireless communication system, up safe transmission method auxiliary based on downstream feedback in a kind of 5G communication system is proposed, 5G ascending communication system cannot be directly applied for solve existing radio physical layer secure transmission technique, or the problem of limited safe performance gain can only be brought.

For reaching above object, the present invention adopts following technical scheme to be achieved:

Based on the up safe transmission method that downstream feedback is auxiliary in 5G communication system, described 5G communication system includes a single-antenna subscriber node Alice, a M root antenna base station Node B ob, and a single antenna passive wiretapping node Eve; Comprise the following steps based on the up safe transmission method that downstream feedback is auxiliary in described 5G communication system:

Step 1, single-antenna subscriber node Alice sends the mixed information including feedback signal transmission requests information and pilot sequence information to base-station node Bob; Base-station node Bob utilizes pilot sequence information to estimate M dimensional vector channel information from single-antenna subscriber node Alice to base-station node Bob;

Step 2, base-station node Bob utilizes the small scale channel information h estimated _aB, the M dimension feedback signal vector designing the safe transmission first stage is wherein β ∈ (0,1) is the power allocation factor between the Human disturbance feedback signal that presets and man made noise's feedback signal, P _bfor the signal transmission power of base-station node Bob, represent the Wave beam forming weighted vector of downstream feedback link maximum ratio transmission, z is the random Gauss AI signal again that distribution meets zero mean unit variance, represent base-station node Bob to single-antenna subscriber node Alice small scale channel null space matrix and Ψ ^hΨ=I, for M-1 ties up random AN signal train vector, each random element of vector obeys average mutually to be independently 0 variance be 1 multiple Gaussian Profile;

Step 3, single-antenna subscriber node Alice and eavesdropping node Eve completes the reception to base-station node Bob feedback signal respectively: the signal that single-antenna subscriber node Alice received in the safe transmission first stage is wherein r represents the distance between single-antenna subscriber node Alice and eavesdropping node Eve, and α represents the path attenuation factor that wireless channel large scale declines, α>=2; n _afor the reception noise at single-antenna subscriber node Alice place; Accordingly, eavesdropping node Eve at the signal that the safe transmission first stage receives is $y_E^1=\sqrt{{\mathrm{\βP}}_B}{r}_{BE}^{-\mathrm{\α}/2}{g}_{EB}^T\frac{h_{AB}^{*}}{\left|\right|h_{AB}\left|\right|}z+\sqrt{\frac{(1-\mathrm{\β})P_B}{M-1}}{r}_{BE}^{-\mathrm{\α}/2}{g}_{EB}^T\mathrm{\Ψ}t+n_E^1,$ Wherein r _bErepresent the distance between base-station node Bob to eavesdropping node Eve, multipath fading channel between representative eavesdropping node Eve to base-station node Bob, for eavesdropping the reception noise at node Eve place;

Step 4, in the second stage of safe transmission, single-antenna subscriber node Alice designs and broadcast singal $a_A=\sqrt{{\mathrm{\ηP}}_A}s+\sqrt{(1-\mathrm{\η})P_A}\frac{\sqrt{{\mathrm{\βP}}_B}{r}^{-\mathrm{\α}/2}\left|\right|h_{AB}\left|\right|z+n_A}{\sqrt{{\mathrm{\βP}}_B{r}^{-\mathrm{\α}}\left|\right|h_{AB}|{|}^2+{\mathrm{\σ}}_A^2}},$ Here η ∈ (0,1) represents the power allocation factor between secret signal s and normalization interference signal, P _arepresent single-antenna subscriber node Alice end signal transmitting power, for random noise n _avariance;

Step 5, base-station node Bob and eavesdropping node Eve completes the reception to single-antenna subscriber node Alice broadcast singal respectively: the vector mixed signal that base-station node Bob receives in safe transmission second stage is $y_B^2=\sqrt{{\mathrm{\ηP}}_A}{r}^{-\mathrm{\α}/2}{h}_{AB}s\sqrt{\left(1-\mathrm{\η}\right)P_A}{r}^{-\mathrm{\α}/2}{h}_{AB}\frac{\sqrt{{\mathrm{\βP}}_B}{r}^{-\mathrm{\α}/2}||h_{AB}||z+n_A}{\sqrt{{\mathrm{\βP}}_B}{r}^{-\mathrm{\α}}{||h_{AB}||}^2+{\mathrm{\σ}}_A^2}+n_B,$ Wherein n _brepresent the reception noise at base-station node Bob place; Correspondingly, the scalar mixing signal that eavesdropping node Eve receives in safe transmission second stage is $y_E^2=\sqrt{{\mathrm{\ηP}}_A}{r}_{AE}^{-\mathrm{\α}/2}{g}_{AE}s+\sqrt{(1-\mathrm{\η})P_A}{r}_{AE}^{-\mathrm{\α}/2}{g}_{AE}\frac{\sqrt{{\mathrm{\βP}}_B}{r}^{-\mathrm{\α}/2}\left|\right|h_{AB}\left|\right|z+n_A}{\sqrt{{\mathrm{\βP}}_B{r}^{-\mathrm{\α}}\left|\right|h_{AB}|{|}^2+{\mathrm{\σ}}_A^2}}+n_E^2,$ Wherein r _aErepresent the distance between single-antenna subscriber node Alice and eavesdropping node Eve, represent the multipath fading channel between single-antenna subscriber node Alice and eavesdropping node Eve, for eavesdropping node Eve is at the reception noise of safe transmission second stage.

When proceeding to the transmit stage of next secret signal, automatically repeat the process in step 1 to step 5.

Based on the up safe transmission method that downstream feedback is auxiliary in 5G communication system, comprise the following steps:

First, in the first stage of safe transmission, multi-antenna base station end utilizes beam-forming technology to send Human disturbance and man made noise's signal on the uplink simultaneously;

Then, single-antenna subscriber end completes the reception transmitted to base station end, and transmits on the signal scrambling received to secret signal pending to form mixing;

Secondly, in the second stage of safe transmission, single-antenna subscriber end is broadcasted this mixing and is transmitted;

Finally, upstream multi-antenna communication base station end completes mixing the reception transmitted, and multi-antenna communication base station utilizes maximum likelihood detection method, from mixing transmits, estimate secret signal exactly.

Compared with safety of physical layer transmission plan existing in prior art, the invention has the advantages that:

1, the present invention is on safe transmission conceptual design, considers simultaneously and has used large scale and the multipath fading information of wireless channel.

2, on security information safe transmission ensures, the present invention has only used the feedback of destination random signal.Compared with existing safe transmission scheme feed back based on key, the present invention, without the need to carrying out necessary key agreement or pre-share operates between receiving-transmitting sides, reduces the resource consumption of system.

3, in the use of feedback signal, scheme designed by the present invention, only in the second stage of secret signal transmission, to the mixed signal including feedback random signal received in the first stage, carries out the energy normalized process of indifference.The present invention, while guarantee system safety performance, does not add other hardware and power loss.

4, the present invention has used the multiple antennas advantage of destination, and compared with the safe transmission scheme fed back based on single antenna destination key of routine, can effectively enhance system security energy.

5, on destination antenna array uses, the present invention's design employs Human disturbance Wave beam forming and man made noise injects this United Technologies, make use of the transmitting degree of freedom of destination fully.

6, two benches through-put power configuration aspect, the present invention is under the poorest safe transmission scene, to maximize the ergodic safe rate of system for target, complete respectively at Human disturbance signal and man made noise's signal, and the optimal power allocation operation between secret signal and normalization mixed signal.Compared with constant power batch operation, two benches optimal power allocation operation of the present invention effectively improves the security performance of system.

Under the present invention considers that wireless communication system is operated in time division duplex (Time Division Duplex, TDD) pattern, system has used the reciprocity of channel in the acquisition of channel information; In addition, in order to weigh between node, relative distance is on the impact of system safety performance, and large scale gain and the small scale gain of wireless fading channel have been taken into account in modeling analysis simultaneously.

In step 1 to 5 of the present invention, each fail safe taking turns Secret Information Transmission all needs the signals transmission in two stages to ensure.

In step 2 of the present invention, the effect of man made noise and Human disturbance is respectively: in the first stage of secret signal safe transmission, and man made noise's signal is used for protecting Human disturbance signal intactly not intercepted by Eve by Bob; In the second stage of safe transmission, do not comprise man made noise's signal due in the signal that Alice received in the first stage, Human disturbance signal is then used for weakening the eavesdropping capability of Eve to secret signal as much as possible by Alice.

Below in conjunction with the drawings and the specific embodiments, the present invention is described in further detail.

Accompanying drawing explanation

Based on the up two benches safe transmission method schematic diagram that downstream feedback is auxiliary in Fig. 1 5G wireless communication system designed by the present invention; Wherein Fig. 1 (A) first stage of transmitting for two benches, also i.e. feedback stage; The second stage that Fig. 1 (B) transmits for two benches is also the forward direction stage of Secret Information Transmission.Single-antenna subscriber A in figure represents single antenna source node Alice, and M antenna base station B represents that M (M >=3) root antenna expects that destination node Bob, single antenna listener-in E represent single antenna passive wiretapping node Eve.

To be that the system under different capacity allocation strategy is ergodic reach safe rate and the ergodic simulation curve comparison diagram reaching safe rate of the poorest safe transmission scene system to Fig. 2.

Fig. 3 is in the poorest safe transmission scene, and different capacity distributes the system safety outage probability simulation curve under setting, system safety outage probability high s/n ratio is similar to simulation curve, system safety outage probability high s/n ratio approximation theory curve comparison figure.

Embodiment

Below in conjunction with attached embodiment illustrated in fig. 1, the embodiment of scheme designed by the present invention is described in detail.

Based on the up safe transmission method that downstream feedback is auxiliary in a kind of 5G of the present invention communication system, comprise the following steps:

Step 1, before two benches transmission is opened, single-antenna subscriber node Alice (in figure single-antenna subscriber A) first sends the mixed information including feedback signal transmission requests information and pilot sequence information to base-station node Bob (in figure M antenna base station B).The pilot sequence information that base-station node Bob utilizes pre-share and the mixed information received, estimate the M dimensional vector channel information from Alice to Bob, and perform the preparation of feedback information transmitting;

Step 2, after completing the estimation to minor channel information (channel of Alice to Bob), base-station node Bob completes the transmission operation of feedback signal.Due to system works in TDD mode and communication channel become slowly, base-station node Bob is first according to the reciprocity of channel between Alice and Bob, and estimated small scale channel information h _aB(being included in the M dimensional vector channel information that step 1 estimates), designing safe transmission first stage downstream feedback link maximum ratio transmission Wave beam forming weighted vector is secondly, designing the null space matrix calculating Bob to Alice channel is here Ψ meets Ψ simultaneously ^hΨ=I.Then, safe rate maximizing performance criterion is reached according to system is ergodic, computing draws in the safe transmission first stage, Human disturbance (Artificial Interference, AI) feedback signal and man made noise (Artificial Noise, AN) the power allocation factor β ∈ (0,1) between feedback signal is

$\mathrm{\β}=\frac{-(M-2){\mathrm{\ρ}}_A+\sqrt{(M-1)(M-2){{\mathrm{\ρ}}_A}^2+(M-1)(M-2){\mathrm{\ρ}}_A{\mathrm{\ρ}}_B}}{{\mathrm{\ρ}}_A+(M-1){\mathrm{\ρ}}_B}.$

Wherein, ρ _aand ρ _bbe respectively the transmitting signal to noise ratio of node Alice and Bob.

Finally, base-station node Bob is according to available signal transmission power P _b, design and launch M n dimensional vector n feedback signal wherein z is the random Gauss AI signal again that distribution meets zero mean unit variance, for M-1 ties up random AN signal phasor, and each random element of vector obeys the multiple Gaussian Profile that average is 0, variance is 1 mutually independently;

Step 3, single-antenna subscriber node Alice and eavesdropping node Eve (in figure single antenna listener-in E) complete the reception to safe transmission first stage base station end feedback signal respectively.Via the effect of corresponding slow change wireless channel, the signal that Alice received in the feedback signal transmission stage is

$y_A^1=\sqrt{{\mathrm{\βP}}_B}{r}^{-\mathrm{\α}/2}\left|\right|h_{AB}\left|\right|z+n_A,$

Wherein r represents the distance between Alice and Bob, and α (α>=2) represents wireless channel paths decay factor, n _afor the reception noise at Alice place.Correspondingly, Eve at the signal that the safe transmission first stage receives is

$y_E^1=\sqrt{{\mathrm{\βP}}_B}{r}_{BE}^{-\mathrm{\α}/2}{g}_{EB}^T\frac{h_{AB}^{*}}{\left|\right|h_{AB}\left|\right|}z+\sqrt{\frac{(1-\mathrm{\β})P_B}{M-1}}{r}_{BE}^{-\mathrm{\α}/2}{g}_{EB}^T\mathrm{\Ψ}t+n_E^1,$

Wherein r _bErepresent the distance between Bob to Eve, represent the multipath fading channel vector between Eve to Bob, for the reception noise of Eve first stage in two benches eavesdropping process;

Step 4, Alice design also broadcast packet contains the mixed signal of secret signal (being contemplated for Bob to receive), to open the second stage of two benches safe transmission.In mixed-signal designs, first Alice to make the normalized on energy at the signal that the first stage receives to it.Secondly, reach safe rate maximizing performance criterion according to system is ergodic equally, the power allocation factor η ∈ (0,1) between design secret signal and normalized signal is,

$\mathrm{\η}=\frac{B-\sqrt{B^2-4(M-1){\left(\mathrm{\β}\right)}^2(M-2){(1-\mathrm{\β})}^2{{\mathrm{\ρ}}_A}^2}}{2(M-1){\left(\mathrm{\β}\right)}^2{\mathrm{\ρ}}_A}$

Here, B=((M-1) (β) ²+ (M-2) (1-β) ²) ρ _a+ (M-1) (β) ²ρ _b.Finally, single-antenna subscriber node Alice is according to self available signal transmission power P _a, design and broadcast mixed signal

$a_A=\sqrt{{\mathrm{\ηP}}_A}s+\sqrt{(1-\mathrm{\η})P_A}\frac{\sqrt{{\mathrm{\βP}}_B}{r}^{-\mathrm{\α}/2}\left|\right|h_{AB}\left|\right|z+n_A}{\sqrt{{\mathrm{\βP}}_B{r}^{-\mathrm{\α}}\left|\right|h_{AB}|{|}^2+{\mathrm{\σ}}_A^2}},$

Wherein s represents secret signal, for random noise n _avariance;

Step 5, secret signal expects that receiving terminal Bob and eavesdropping node Eve completes the reception of the mixed signal to Alice broadcast respectively.Through the impact of respective wireless fading channel, the vector signal that Bob receives in safe transmission second stage is

$y_B^2=\sqrt{{\mathrm{\ηP}}_A}{r}^{-\mathrm{\α}/2}{h}_{AB}s\sqrt{\left(1-\mathrm{\η}\right)P_A}{r}^{-\mathrm{\α}/2}{h}_{AB}\frac{\sqrt{{\mathrm{\βP}}_B}{r}^{-\mathrm{\α}/2}||h_{AB}||z+n_A}{\sqrt{{\mathrm{\βP}}_B}{r}^{-\mathrm{\α}}{||h_{AB}||}^2+{\mathrm{\σ}}_A^2}+n_B,$

Wherein n _brepresent the reception noise at Bob place.Further, due to known self send out AI signal z, Bob eliminates z and also makes maximum-ratio combing to above-mentioned vector signal and receive operation, obtains Received signal strength

$y_B=\sqrt{{\mathrm{\ηP}}_A}{r}^{-\mathrm{\α}/2}\left|\right|h_{AB}\left|\right|s+\sqrt{\left(1-\mathrm{\η}\right)P_A}{r}^{-\mathrm{\α}/2}\left|\right|h_{AB}\left|\right|\frac{n_A}{\sqrt{{\mathrm{\βP}}_B}{r}^{-\mathrm{\α}}{||h_{AB}||}^2+{\mathrm{\σ}}_A^2}+\frac{h_{AB}^H}{\left|\right|h_{AB}\left|\right|}+n_B.$

Correspondingly, the signal that Eve receives in safe transmission second stage is

$y_E^2=\sqrt{{\mathrm{\ηP}}_A}{r}_{AE}^{-\mathrm{\α}/2}{g}_{AE}s+\sqrt{(1-\mathrm{\η})P_A}{r}_{AE}^{-\mathrm{\α}/2}{g}_{AE}\frac{\sqrt{{\mathrm{\βP}}_B}{r}^{-\mathrm{\α}/2}\left|\right|h_{AB}\left|\right|z+n_A}{\sqrt{{\mathrm{\βP}}_B{r}^{-\mathrm{\α}}\left|\right|h_{AB}|{|}^2+{\mathrm{\σ}}_A^2}}+n_E^2,$

Wherein r _aErepresent the distance between Alice and Eve, represent the multipath fading channel between Alice and Eve, for the reception noise of the second stage that Eve eavesdrops at two benches;

Step 6, when proceeding to the transmit stage of next secret signal, system repeats the two benches secure transfer process in above-mentioned steps 1 to step 5 automatically.

In above-mentioned steps 5, Bob utilizes maximum likelihood detection method, can from y _bin estimate secret signal s exactly.And on the other hand, because Eve cannot know any prior information about scalar AI signal and vector AN signal, thus cannot from two benches Received signal strength with obtain about the accurate estimation of secret signal s, thus the effective guarantee fail safe of secret signal transmission.

To set M=4, Fig. 2 and Fig. 3 respectively depict ergodic under the input of multiple gaussian signal and different parameters and scene suppose of system and reaches safe rate and security interrupt probability performance curve, further from the angle of system safety performance emulation, illustrate the present invention quantitatively and ensureing the effect in 5G up single input and multi-output (SIMO) system wireless safe transmission.

To be that the system under different capacity allocation strategy is ergodic reach safe rate and the ergodic simulation curve comparison diagram reaching safe rate of the poorest safe transmission scene system to Fig. 2.In figure and aR _sergodic under optimal power allocation and constant power distribute of representative system reaches safe rate respectively; with represent in the poorest safe transmission scene respectively, ergodic under optimal power allocation of system reaches safe rate, ergodic under constant power distributes reach the high s/n ratio approximation of safe rate and constant power distribute under ergodicly reach safe rate; ρ _aand ρ _bbe respectively the transmitting signal to noise ratio of node Alice and Bob.

Fig. 3 is in the poorest safe transmission scene, and different capacity distributes the system safety outage probability simulation curve under setting, system safety outage probability high s/n ratio is similar to simulation curve, system safety outage probability high s/n ratio approximation theory curve comparison figure.In figure represent in the poorest safe transmission scene respectively, the system safety outage probability under given power division, the system safety outage probability high s/n ratio under given power division be similar to, system safety outage probability under optimal power allocation; represent the targeted security speed preset.

Claims (6)

1. in a 5G communication system based on the up safe transmission method that downstream feedback is auxiliary, it is characterized in that, described 5G communication system includes a single-antenna subscriber node Alice, a M root antenna base station Node B ob, and a single antenna passive wiretapping node Eve; Comprise the following steps based on the up safe transmission method that downstream feedback is auxiliary in described 5G communication system:

Step 1, single-antenna subscriber node Alice sends the mixed information including feedback signal transmission requests information and pilot sequence information to base-station node Bob; Base-station node Bob utilizes pilot sequence information to estimate M dimensional vector channel information from single-antenna subscriber node Alice to base-station node Bob;

Step 2, base-station node Bob utilizes the small scale channel information h estimated _aB, the M dimension feedback signal vector designing the safe transmission first stage is wherein β ∈ (0,1) is the power allocation factor between the Human disturbance feedback signal that presets and man made noise's feedback signal, P _bfor the signal transmission power of base-station node Bob, represent the Wave beam forming weighted vector of downstream feedback link maximum ratio transmission, z is the random Gauss AI signal again that distribution meets zero mean unit variance, represent base-station node Bob to single-antenna subscriber node Alice small scale channel null space matrix and Ψ ^hΨ=I, for M-1 ties up random AN signal train vector, each random element of vector obeys average mutually to be independently 0 variance be 1 multiple Gaussian Profile;

Step 3, single-antenna subscriber node Alice and eavesdropping node Eve completes the reception to base-station node Bob feedback signal respectively: the signal that single-antenna subscriber node Alice received in the safe transmission first stage is wherein r represents the distance between single-antenna subscriber node Alice and eavesdropping node Eve, and α represents the path attenuation factor that wireless channel large scale declines, α>=2; n _afor the reception noise at single-antenna subscriber node Alice place; Accordingly, eavesdropping node Eve at the signal that the safe transmission first stage receives is $y_E^1=\sqrt{{\mathrm{\βP}}_B}{r}_{BE}^{-\mathrm{\α}/2}{g}_{EB}^T\frac{h_{AB}^{*}}{\left|\right|h_{AB}\left|\right|}z+\sqrt{\frac{(1-\mathrm{\β})P_B}{M-1}}{r}_{BE}^{-\mathrm{\α}/2}{g}_{EB}^T\mathrm{\Ψ}t+n_E^1,$ Wherein r _bErepresent the distance between base-station node Bob to eavesdropping node Eve, multipath fading channel between representative eavesdropping node Eve to base-station node Bob, for eavesdropping the reception noise at node Eve place;

Step 4, in the second stage of safe transmission, single-antenna subscriber node Alice designs and broadcast singal

$a_A=\sqrt{{\mathrm{\ηP}}_A}s+\sqrt{(1-\mathrm{\η})P_A}\frac{\sqrt{{\mathrm{\βP}}_B}{r}^{-\mathrm{\α}/2}\left|\right|h_{AB}\left|\right|z+n_A}{\sqrt{{\mathrm{\βP}}_B{r}^{-\mathrm{\α}}\left|\right|h_{AB}|{|}^2+{\mathrm{\σ}}_A^2}},$ Here η ∈ (0,1) represents the power allocation factor between secret signal s and normalization interference signal, P _arepresent single-antenna subscriber node Alice end signal transmitting power, for random noise n _avariance;

Step 5, base-station node Bob and eavesdropping node Eve completes the reception to single-antenna subscriber node Alice broadcast singal respectively: the vector mixed signal that base-station node Bob receives in safe transmission second stage is

$y_B^2=\sqrt{{\mathrm{\ηP}}_A}{r}^{-\mathrm{\α}/2}{h}_{AB}s+\sqrt{(1-\mathrm{\η})P_A}{r}^{-\mathrm{\α}/2}{h}_{AB}\frac{\sqrt{{\mathrm{\βP}}_B}{r}^{-\mathrm{\α}/2}\left|\right|h_{AB}\left|\right|z+n_A}{\sqrt{{\mathrm{\βP}}_B}{r}^{-\mathrm{\α}}\left|\right|h_{AB}|{|}^2+{\mathrm{\σ}}_A^2}+n_B,$ Wherein n _brepresent the reception noise at base-station node Bob place; Correspondingly, the scalar mixing signal that eavesdropping node Eve receives in safe transmission second stage is

$y_E^2=\sqrt{{\mathrm{\ηP}}_A}{r}_{AE}^{-\mathrm{\α}/2}{g}_{AE}s+\sqrt{(1-\mathrm{\η})P_A}{r}_{AE}^{-\mathrm{\α}/2}{g}_{AE}\frac{\sqrt{{\mathrm{\βP}}_B}{r}^{-\mathrm{\α}/2}\left|\right|h_{AB}\left|\right|z+n_A}{\sqrt{{\mathrm{\βP}}_B{r}^{-\mathrm{\α}}\left|\right|h_{AB}|{|}^2+{\mathrm{\σ}}_A^2}}+n_E^2,$ Wherein r _aErepresent the distance between single-antenna subscriber node Alice and eavesdropping node Eve, represent the multipath fading channel between single-antenna subscriber node Alice and eavesdropping node Eve, for eavesdropping node Eve is at the reception noise of safe transmission second stage.

2. in a kind of 5G communication system according to claim 1 based on the up safe transmission method that downstream feedback is auxiliary, it is characterized in that, when proceeding to the transmit stage of next secret signal, automatically repeating the process in step 1 to step 5.

3. in a kind of 5G communication system according to claim 1 based on the up safe transmission method that downstream feedback is auxiliary, it is characterized in that, M >=3.

4. in a kind of 5G communication system according to claim 1 based on the up safe transmission method that downstream feedback is auxiliary, it is characterized in that, in step 5, base-station node Bob utilizes maximum likelihood detection method, from y _bin estimate secret signal s exactly.

5. in 5G communication system based on the up safe transmission method that downstream feedback is auxiliary, it is characterized in that, comprise the following steps:

First, in the first stage of safe transmission, multi-antenna base station end utilizes beam-forming technology to send Human disturbance and man made noise's signal on the uplink simultaneously;

Then, single-antenna subscriber end completes the reception transmitted to base station end, and transmits on the signal scrambling received to secret signal pending to form mixing;

Secondly, in the second stage of safe transmission, single-antenna subscriber end is broadcasted this mixing and is transmitted;

Finally, upstream multi-antenna communication base station end completes mixing the reception transmitted.

6. in a kind of 5G communication system according to claim 5 based on the up safe transmission method that downstream feedback is auxiliary, it is characterized in that, multi-antenna communication base station utilizes maximum likelihood detection method, from mixing transmits, estimate secret signal exactly.