CN105744516A - Communication system and method for improving security performance of physical layer by energy station - Google Patents

Abstract

The invention relates to a communication system and method for improving the security performance of a physical layer by an energy station. The communication system comprises a source node, a legitimate receiving node, an eavesdropping receiving node and the energy station; the energy station is equipped with N antennas, the source node is equipped with M antennas, and the legitimate receiving node and the eavesdropping receiving node are equipped with a single antenna respectively; the energy station and the source node constitute a wireless energy transmission subsystem; the source node and the legitimate receiving node constitute a wireless signal transmission subsystem; the energy station, the legitimate receiving node and the eavesdropping receiving node constitute a wireless interference signal transmission subsystem; and the energy station is provided with a beamformer w. The invention further relates to a method for improving the security performance of the physical layer by the energy station. The energy station can not only serve as a terminal to provide energy for the source node, but also can serve as an interference source and transmit a wireless interference signal, and the wireless interference signal generates relatively large interference to the eavesdropping receiving node, so the security performance of the physical layer is greatly improved.

Description

A kind of communication system utilizing energy station to promote safety of physical layer performance and method

Technical field

The present invention relates to the communications field, be specifically related to a kind of communication system utilizing energy station to promote safety of physical layer performance and method.

Background technology

Along with developing rapidly of wireless communication technology, various Wireless Telecom Equipments sharply increase, and thing followed secure wireless communication sex chromosome mosaicism is also on the rise.Traditional secure wireless communication mechanism is mainly the associated encryption technology based on cryptography, but along with the rapid lifting of Computing ability, the secrecy basis of this technology becomes no longer firm, and safety of physical layer technology is arisen at the historic moment.

Radio communication safety of physical layer technology, from information-theoretical angle, utilizes uniqueness and the reciprocity of physical channel, realizes information encryption, identification validated user etc., it is intended to realize unconditional security.Chinese invention patent publication number (CN103986545A) discloses a kind of safe transmission method of physical layer for SIMO wireless communication system, first expectation recipient's back emitted random reference signal, then launch party uses the reference signal received to launch after symbol to be transmitted carries out scramble, and finally expectation recipient utilizes known reference signal to be demodulated obtaining the information of launch party's transmission to received signal.It is worthy of note, this patent of invention only discloses launch party perfect can receive the situation of the expectation reverse random reference signal of recipient, it does not have consider the scene of limited channel status information feedback.

On the other hand, along with continuing to bring out of emerging wireless traffic, the cruising time of mobile communication equipment is increasingly becoming the key factor affecting Consumer's Experience.Under the background that wireless energy transmission technology is constantly ripe, research worker proposes and disposes fixing supply station in a communication network, utilizes wireless energy transmission technology to provide energy for the mobile equipment in network.Currently, although the novel wireless communication network architecture introducing supply station has caused international extensive concern, but correlational study work is still in the starting stage, it is limited only to provide energy into mobile equipment to the application of supply station, not yet fully excavates the potential of supply station.

Summary of the invention

Present invention aims to the deficiencies in the prior art, it is provided that a kind of communication system utilizing energy station to promote safety of physical layer performance and method.

For solving above-mentioned technical problem, technical scheme provided by the present invention is:

A kind of communication system utilizing energy station to promote safety of physical layer performance, described communication system includes source node, legitimate receipt node, eavesdropping receiving node and energy station；Described energy station is configured with N root antenna, and source node is configured with M root antenna, legitimate receipt node and eavesdropping receiving node configuration single antenna；Described energy station and source node constitute wireless energy transfer subsystem；Described source node, legitimate receipt node and eavesdropping receiving node constitute transmission of wireless signals subsystem；Described energy station, legitimate receipt node and eavesdropping receiving node constitute wireless interference signal transmission subsystem；Described energy station design has beamformer w.

In technique scheme, energy station can not only provide energy as terminal for source node, can be used as an interference source simultaneously, by launching wireless interference signal so that eavesdropping receiving node is produced interference by wireless interference signal.Energy station design beamformer w, its objective is to minimize the interfering energy of legitimate receipt node so that wireless interference signal maximizes the interfering energy eavesdropping receiving node, thus promoting the safety of physical layer performance of whole communication system simultaneously.

As improvement, described energy station is based on the channel condition information acquisition degree to two interference channels in wireless interference signal transmission subsystem, and energy station designs corresponding beamformer w.

Described communication system carries out energy transmission and information transmission, wherein 0 < θ < 1 respectively in a time slot T according to time distribution factor θ；In front θ T time, energy station transmits wireless energy to source node；In rear (1-θ) T time, source node is to legitimate receipt node-node transmission wireless signal, and described wireless signal is eavesdropped by eavesdropping receiving node, and energy station launches wireless interference signal to legitimate receipt node and eavesdropping receiving node simultaneously.

As improvement, described energy station designs corresponding beamformer w and comprises the steps:

1) energy station is by intercepting legitimate receipt node and the pilot tone of eavesdropping receiving node, estimates the channel condition information of two interference channels；

2) if energy station can estimate the channel condition information between energy station with corresponding legitimate receipt node and eavesdropping receiving node, then energy station design beamformer w₁, use zero-forcing technique to eliminate the wireless interference signal impact on legal receiving node, maximize the wireless interference signal to eavesdropping receiving node simultaneously；Otherwise proceed to step 3)；

3) if energy station can estimate the channel condition information of energy station and corresponding legitimate receipt node, but it is unable to estimate the channel condition information between energy station and eavesdropping receiving node, then energy station design beamformer w₂, use zero-forcing technique to eliminate the wireless interference signal to legal receiving node；Otherwise proceed to step 4)；

4) if energy station can estimate the channel condition information between portion of energy station and legitimate receipt node, but the channel condition information between energy station and eavesdropping receiving node cannot be obtained；

Then energy station design beamformer w₃, legitimate receipt node by the code book vector feedback the strongest with actual interference channel orthogonality to energy station, energy station directly with this vector as beamformer w₃；

Or, energy station design beamformer w₄Legitimate receipt node by the code book vector feedback that mates most with actual interference channel to energy station, this code book vector mated most is considered as the best channel conditions information between itself and legitimate receipt node and estimates by energy station, and uses zero-forcing technique to eliminate the wireless interference signal to legal receiving node.

Described step 2) in beamformer w₁Its object function and constraints can be expressed as:

$w_1=\arg \underset{w_1}{max}{\left|h_{JE}^T{w}_1\right|}^2$

$\begin{array}{ccc}s.t.& h_{JD}^T{w}_1=0,& ||w_1||=1\end{array}$

Wherein, w₁Represent beamformer, h_JDAnd h_JERepresenting the channel condition information of energy station and legitimate receipt node and energy station and eavesdropping receiving node respectively, T represents transposition operative symbol；

Obtained beamformer w₁For:

$w_1=\frac{{\&Pi;}_{h_{JD}}{h^{\&prime;}}_{JE}}{\sqrt{h_{JE}^T{\&Pi;}_{h_{JD}}{h^{\&prime;}}_{JE}}}$

Wherein, ' represent conjugate operation symbol,Represent h_JDThe orthocomplement, orthogonal complement of column space, I_NRepresent N rank unit matrix.

Described step 3) in beamformer w₂ForAny one in the N-1 of singular value decomposition left singular vector, wherein N is the number of antennas of energy station.

Described step 4) in beamformer w₃For:

$w_3={\hat{h}}_{opt}=\arg \underset{{\hat{h}}_i\&Element;C}{\min }{\left|{\tilde{h}}^T{\hat{h}}_i\right|}^2$

Wherein,Represent the direction vector of energy station and the response of legitimate receipt inter-nodal channel,Representing code book vector, C represents code book set,Represent the code book vector that orthogonality is the strongest.

Described step 4) in beamformer w₄For:

$w_4={\hat{h}}_{opt}=\arg \underset{{\hat{h}}_i\&Element;C}{max}{\left|{\tilde{h}}^T{{\hat{h}}^{\&prime;}}_i\right|}^2$

Wherein,Represent the direction vector of energy station and the response of legitimate receipt inter-nodal channel,Representing code book vector, C represents code book set,Represent the code book vector mated most.

The present invention also provides for a kind of method utilizing energy station to promote safety of physical layer performance based on above-mentioned communication system, comprises the steps:

(1) energy station transmits wireless energy to source node in front θ T time；

(2) energy station is by intercepting legitimate receipt node and the pilot tone of eavesdropping receiving node, estimates the channel condition information of two interference channels；

(3) energy station obtains the corresponding beamformer w of Program design based on the channel condition information of two interference channels；

(4) in rear (1-θ) T time, source node is to legitimate receipt node-node transmission wireless signal, described wireless signal is eavesdropped by eavesdropping receiving node, and energy station adopts beamformer w to legitimate receipt node and to eavesdrop receiving node transmission wireless interference signal simultaneously.

Compared with the existing technology, beneficial effects of the present invention is embodied in:

(1) present invention considers a kind of communication system utilizing energy station to promote safety of physical layer performance, original tapping channel classical model introduces wireless energy transmission technology, energy is provided to the device end in system by energy station, establish the model that a kind of range of application is wider, more practical, avoid conventional model and be merely able to be applicable to the constraint of low power consumption wireless device terminal, be effectively improved the flying power of device end.

(2) present invention consider energy station for terminal provide energy it is also possible to launch interference signal as interference source.Based on the channel condition information acquisition degree to two interference channels, energy station adjustment also obtains corresponding optimum beam figuration device w.By designing so that legal receiving node is produced less impact by interference signal while eavesdropping receiving node is produced larger interference, thus the secret and safe performance of whole communication system is substantially improved.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of the communication system of the present invention；

Fig. 2 is that the present invention utilizes energy station to promote the flow chart of safety of physical layer performance；

Fig. 3 is the flow chart that energy station of the present invention designs corresponding beamformer w；

Fig. 4 be the present invention under beamformer four kinds different, the graph of relation that the secrecy Outage probability of distributed antenna after optimization changes with main channel average signal-to-noise ratio.

Detailed description of the invention

Below in conjunction with embodiment and accompanying drawing, the present invention is further described.

As it is shown in figure 1, utilize energy station to promote the communication system of safety of physical layer performance, described communication system includes source node, legitimate receipt node, eavesdropping receiving node and energy station；Described energy station is configured with N root antenna, and source node is configured with M root antenna, legitimate receipt node and eavesdropping receiving node configuration single antenna；Described energy station and source node constitute wireless energy transfer subsystem；Described source node, legitimate receipt node and eavesdropping receiving node constitute transmission of wireless signals subsystem；Described energy station, legitimate receipt node and eavesdropping receiving node constitute wireless interference signal transmission subsystem；Described energy station design beamformer w.

Described energy station is based on the channel condition information acquisition degree to two interference channels in wireless interference signal transmission subsystem, and energy station designs corresponding beamformer w.

Described communication system carries out energy transmission and information transmission, wherein 0 < θ < 1 respectively in a time slot T according to time distribution factor θ；In front θ T time, energy station transmits wireless energy to source node；In rear (1-θ) T time, source node is to legitimate receipt node-node transmission wireless signal, and described wireless signal is eavesdropped by eavesdropping receiving node, and energy station launches wireless interference signal to legitimate receipt node and eavesdropping receiving node simultaneously.

As in figure 2 it is shown, the method utilizing energy station to promote safety of physical layer performance, comprise the steps:

(1) energy station transmits wireless energy to source node in front θ T time；

(2) energy station is by intercepting legitimate receipt node and the pilot tone of eavesdropping receiving node, estimates the channel condition information of two interference channels；

(3) energy station obtains the corresponding beamformer w of Program design based on the channel condition information of two interference channels；

(4) in rear (1-θ) T time, source node is to legitimate receipt node-node transmission wireless signal, described wireless signal is eavesdropped by eavesdropping receiving node, and energy station adopts beamformer w to legitimate receipt node and to eavesdrop receiving node transmission wireless interference signal simultaneously.

Comprise the steps: as it is shown on figure 3, described energy station designs corresponding beamformer w

1) energy station is by intercepting legitimate receipt node and the pilot tone of eavesdropping receiving node, estimates the channel condition information of two interference channels；

2) if energy station can estimate the channel condition information between energy station with corresponding legitimate receipt node and eavesdropping receiving node, then energy station design beamformer w₁, using zero-forcing technique to eliminate the wireless interference signal impact on legal receiving node, maximize the wireless interference signal to eavesdropping receiving node simultaneously, its object function and constraints can be expressed as:

$w_1=\arg \underset{w_1}{max}{\left|h_{JE}^T{w}_1\right|}^2$

$\begin{array}{ccc}s.t.& h_{JD}^T{w}_1=0,& ||w_1||=1\end{array}$

Wherein, w₁Represent beamformer, h_JDAnd h_JERepresenting the channel condition information of energy station and legitimate receipt node and energy station and eavesdropping receiving node respectively, T represents transposition operative symbol；

Obtained beamformer w₁For:

$w_1=\frac{{\&Pi;}_{h_{JD}}{h^{\&prime;}}_{JE}}{\sqrt{h_{JE}^T{\&Pi;}_{h_{JD}}{h^{\&prime;}}_{JE}}}$

Wherein, ' represent conjugate operation symbol,Represent h_JDThe orthocomplement, orthogonal complement of column space, I_NRepresent N rank unit matrix.

Otherwise proceed to step 3)；

3) if energy station can estimate the channel condition information of energy station and corresponding legitimate receipt node, but it is unable to estimate the channel condition information between energy station and eavesdropping receiving node, then energy station design beamformer w₂, use zero-forcing technique to eliminate the wireless interference signal to legal receiving node, described beamformer w₂ForAny one in the N-1 of singular value decomposition left singular vector, wherein N is the number of antennas of energy station；

Otherwise proceed to step 4)；

4) if energy station can estimate the channel condition information between portion of energy station and legitimate receipt node, but the channel condition information between energy station and eavesdropping receiving node cannot be obtained；

Then energy station design beamformer w₃, legitimate receipt node by the code book vector feedback the strongest with actual interference channel orthogonality to energy station, energy station directly with this vector as beamformer w₃, described beamformer w₃For:

$w_3={\hat{h}}_{opt}=\arg \underset{{\hat{h}}_i\&Element;C}{\min }{\left|{\tilde{h}}^T{\hat{h}}_i\right|}^2$

Wherein,Represent the direction vector of energy station and the response of legitimate receipt inter-nodal channel,Representing code book vector, C represents code book set,Represent the code book vector that orthogonality is the strongest.

Or, energy station design beamformer w₄Legitimate receipt node by the code book vector feedback that mates most with actual interference channel to energy station, this code book vector mated most is considered as the best channel conditions information between itself and legitimate receipt node and estimates by energy station, and use zero-forcing technique to eliminate the wireless interference signal to legal receiving node, described beamformer w₄For:

$w_4={\hat{h}}_{opt}=\arg \underset{{\hat{h}}_i\&Element;C}{max}{\left|{\tilde{h}}^T{{\hat{h}}^{\&prime;}}_i\right|}^2$

Wherein,Represent the direction vector of energy station and the response of legitimate receipt inter-nodal channel,Representing code book vector, C represents code book set,Represent the code book vector mated most.

Specific embodiment: comprise a source node in this system, one legitimate receipt node, one eavesdropping receiving node and an energy station that interference can be launched, the energy utilization efficiency of source node is 80%, time distribution factor is 0.5, the multiple antennas number of energy station is 4, and the multiple antennas number of source node is 2.

For the performance change of proof system, the present embodiment adopts secrecy Outage probability of distributed antenna parameter to be analyzed.Fig. 4 is in the present embodiment under four kinds of different beams figuration devices, the graph of relation that secrecy Outage probability of distributed antenna changes with main channel average signal-to-noise ratio.It can be seen that along with the increase of main channel average signal-to-noise ratio, the outage probability of system constantly reduces, namely the performance of system constantly promotes.Find by contrasting, beamformer w₁Performance to be far superior to other three kinds of beamformer, this is because at beamformer w₁Middle energy station, by intercepting legitimate receipt node and the pilot tone of eavesdropping receiving node, can estimate the channel response of two channels, thus taking full advantage of the benefit of multiple antennas.And beamformer w₂After interference impact on legal receiving node is completely eliminated, performance suboptimum.In the contrast of most latter two beamformer, beamformer w₃Performance be better than beamformer w₄, this is because beamformer w₃Directly have chosen the beamformer w that the interference of legal receiving node is minimum₃, and beamformer w₄Although employing zero-forcing technique, but the code book vector fed back has certain error with actual channel.

The foregoing is only the preferred embodiment of the present invention, not in order to limit the present invention, all within the spirit and principles in the present invention, any amendment of making, equivalent replacement, improvement etc., should be included within protection scope of the present invention.

Claims (9)

1. one kind utilizes the communication system that energy station promotes safety of physical layer performance, it is characterised in that described communication system includes source node, legitimate receipt node, eavesdropping receiving node and energy station；Described energy station is configured with N root antenna, and source node is configured with M root antenna, legitimate receipt node and eavesdropping receiving node configuration single antenna；Described energy station and source node constitute wireless energy transfer subsystem；Described source node, legitimate receipt node and eavesdropping receiving node constitute transmission of wireless signals subsystem；Described energy station, legitimate receipt node and eavesdropping receiving node constitute wireless interference signal transmission subsystem；Described energy station design beamformer w.

2. the communication system utilizing energy station to promote safety of physical layer performance according to claim 1, it is characterized in that, described energy station is based on the channel condition information acquisition degree to two interference channels in wireless interference signal transmission subsystem, and energy station designs corresponding beamformer w.

3. the communication system utilizing energy station to promote safety of physical layer performance according to claim 1 and 2, it is characterized in that, described communication system carries out energy transmission and information transmission, wherein 0 < θ < 1 respectively in a time slot T according to time distribution factor θ；In front θ T time, energy station transmits wireless energy to source node；In rear (1-θ) T time, source node is to legitimate receipt node-node transmission wireless signal, and described wireless signal is eavesdropped by eavesdropping receiving node, and energy station launches wireless interference signal to legitimate receipt node and eavesdropping receiving node simultaneously.

4. the communication system utilizing energy station to promote safety of physical layer performance according to claim 2, it is characterised in that described energy station designs corresponding beamformer w and comprises the steps:

1) energy station is by intercepting legitimate receipt node and the pilot tone of eavesdropping receiving node, estimates the channel condition information of two interference channels；

2) if energy station can estimate the channel condition information between energy station with corresponding legitimate receipt node and eavesdropping receiving node, then energy station design beamformer w₁, use zero-forcing technique to eliminate the wireless interference signal impact on legal receiving node, maximize the wireless interference signal to eavesdropping receiving node simultaneously；Otherwise proceed to step 3)；

3) if energy station can estimate the channel condition information of energy station and corresponding legitimate receipt node, but it is unable to estimate the channel condition information between energy station and eavesdropping receiving node, then energy station design beamformer w₂, use zero-forcing technique to eliminate the wireless interference signal to legal receiving node；Otherwise proceed to step 4)；

4) if energy station can estimate the channel condition information between portion of energy station and legitimate receipt node, but the channel condition information between energy station and eavesdropping receiving node cannot be obtained；

Then energy station design beamformer w₃, legitimate receipt node by the code book vector feedback the strongest with actual interference channel orthogonality to energy station, energy station directly with this vector as beamformer w₃；

Or, energy station design beamformer w₄Legitimate receipt node by the code book vector feedback that mates most with actual interference channel to energy station, this code book vector mated most is considered as the best channel conditions information between itself and legitimate receipt node and estimates by energy station, and uses zero-forcing technique to eliminate the wireless interference signal to legal receiving node.

5. according to claim 4 utilize energy station promote safety of physical layer performance communication system, it is characterised in that described step 2) in beamformer w₁Its object function and constraints can be expressed as:

$w_1=\arg \underset{w_1}{max}{\left|h_{JE}^T{w}_1\right|}^2$

$\begin{array}{ccc}s.t.& h_{JD}^T{w}_1=0,& ||w_1||=1\end{array}$

Wherein, w₁Represent beamformer, h_JDAnd h_JERepresenting the channel condition information of energy station and legitimate receipt node and energy station and eavesdropping receiving node respectively, T represents transposition operative symbol；

Obtained beamformer w₁For:

$w_1=\frac{{\&Pi;}_{h_{JD}}{h^{\&prime;}}_{JE}}{\sqrt{h_{JE}^T{\&Pi;}_{h_{JD}}{h^{\&prime;}}_{JE}}}$

Wherein, ' represent conjugate operation symbol,Represent h_JDThe orthocomplement, orthogonal complement of column space, I_NRepresent N rank unit matrix.

6. according to claim 4 utilize energy station promote safety of physical layer performance communication system, it is characterised in that described step 3) in beamformer w₂ForAny one in the N-1 of singular value decomposition left singular vector, wherein N is the number of antennas of energy station.

7. according to claim 4 utilize energy station promote safety of physical layer performance communication system, it is characterised in that described step 4) in beamformer w₃For:

$w_3={\hat{h}}_{opt}=\arg \underset{{\hat{h}}_i\&Element;C}{min}{\left|{\tilde{h}}^T{\hat{h}}_i\right|}^2$

Wherein,Represent the direction vector of energy station and the response of legitimate receipt inter-nodal channel,Representing code book vector, C represents code book set,Represent the code book vector that orthogonality is the strongest.

8. according to claim 4 utilize energy station promote safety of physical layer performance communication system, it is characterised in that described step 4) in beamformer w₄For:

$w_4={\hat{h}}_{opt}=\arg \underset{{\hat{h}}_i\&Element;C}{max}{\left|{\tilde{h}}^T{{\hat{h}}^{\&prime;}}_i\right|}^2$

Wherein,Represent the direction vector of energy station and the response of legitimate receipt inter-nodal channel,Representing code book vector, C represents code book set,Represent the code book vector mated most.

9. the method utilizing energy station lifting safety of physical layer performance based on the arbitrary described communication system of claim 1～8, it is characterised in that comprise the steps:

(1) energy station transmits wireless energy to source node in front θ T time；

(2) energy station is by intercepting legitimate receipt node and the pilot tone of eavesdropping receiving node, estimates the channel condition information of two interference channels；

(3) energy station obtains the corresponding beamformer w of Program design based on the channel condition information of two interference channels；

(4) in rear (1-θ) T time, source node is to legitimate receipt node-node transmission wireless signal, described wireless signal is eavesdropped by eavesdropping receiving node, and energy station adopts beamformer w to legitimate receipt node and to eavesdrop receiving node transmission wireless interference signal simultaneously.