CN107295623B - The communication means and full duplex relaying system of a kind of full duplex relaying system - Google Patents

Abstract

The present invention discloses a communication method of a full-duplex relay system and a full-duplex relay system. In time slot t=1, a signal source _S sends a signal x( t), R receives and decodes x(t); at time slot t+1, if R decodes successfully, R sends the decoded signal x(t) to D with power P _R , and S uses P _S sends a new signal x(t+1) to R, and R receives and decodes the signal x(t+1) under the loop self-interference of signal x(t); in time slot t+1, if If R fails to decode, _S sends a new signal x(t+1) to R with PS, and _R receives and decodes the signal x(t+1), where PS and _PR are based on information-interference Adaptive power allocation strategy based on coupling characteristics or joint source-relay power allocation strategy determination based on information-interference coupling characteristics. The invention achieves the purpose of improving the system energy efficiency under the condition of meeting the target interruption probability by rationally allocating the transmission power of the information source and the relay.

Description

Communication method of a full-duplex relay system and full-duplex relay system

technical field

The invention belongs to the technical field of wireless communication, and more specifically relates to a communication method of a full-duplex relay system and the full-duplex relay system.

Background technique

Since the cooperative relay technology can effectively expand the coverage of the wireless communication system and enhance the robustness of the system, it has become one of the key technologies of the wireless communication system. Traditionally, relay nodes generally work in half-duplex mode, and must allocate mutually orthogonal channel resources for receiving and sending signals. This seriously damages the spectrum utilization of the wireless communication system. In order to make up for the spectral efficiency loss caused by the traditional half-duplex relay mode, researchers have proposed a full-duplex relay forwarding technology.

By deploying at least two antennas, the full-duplex relay node can receive the new signal sent by the source of the current time slot while forwarding the signal received in the previous time slot. Compared with the traditional half-duplex relay system, theoretically, the full-duplex relay system can almost double the spectral efficiency. However, since the forwarded signal of the full-duplex relay will cause loop self-interference to the target received signal, the coupling characteristics of the information signal and the self-interference signal are caused. On the one hand, if the transmit power of the relay node is too small, the communication quality of the "relay-sink" link will be damaged; on the other hand, if the transmit power of the relay node is too large, it will cause serious loop self-interference, and then Impairs the communication quality of the "source-to-relay" link. Therefore, in order to effectively improve the communication performance of the full-duplex relay system, it is necessary to balance the mutual constraints between the information signal and the interference signal, as well as between the source transmit power and the relay transmit power.

In the current full-duplex relay system, although a lot of work has considered the loop self-interference problem of the full-duplex relay node, there is no such thing as the mutual constraint relationship between the source transmit power and the relay transmit power. The angle optimizes system performance, so better system energy efficiency cannot be obtained.

Contents of the invention

In view of the above defects or improvement needs of the prior art, the object of the present invention is to provide a communication method of a full-duplex relay system and a full-duplex relay system, thereby solving the problem of the existing full-duplex single relay system The technical problem of low energy efficiency of the medium system.

In order to achieve the above object, according to one aspect of the present invention, a communication method for a full-duplex relay system is provided, which is characterized in that it includes:

S1. At time slot t=1, the source _S generates a signal x(t), and sends the signal x(t) to the full-duplex relay node R with power PS, and the full-duplex relay node R performs the signal x(t) The signal x(t) is received and decoded, wherein the power PS is _determined by a preset power allocation strategy;

S2. If the full-duplex relay node R can successfully decode, execute step S3, otherwise execute step S4;

S3. At time slot t+1, the full-duplex relay node R sends a successfully decoded signal x(t) to the sink D with the power P _R , and at the same time, the source S sends the signal x(t) to the sink D with the power P _S The new signal x(t+1) generated by the full-duplex relay node R is sent, and the signal x(t+1) is performed by the full-duplex relay node R under the loop self-interference of the signal x(t). Receive and decode, and then perform step S5, wherein the power P _R is determined by the preset power allocation strategy;

S4. At time slot t+1, the source _S sends the generated new signal x(t+1) to the full-duplex relay node R with the power PS, and the full-duplex relay The node R receives and decodes the signal x(t+1), and then performs step S5;

S5. Judging whether the signal transmission process is completed, if completed, execute step S6; otherwise, return to execute step S2;

S6. Judging whether the relay node R can successfully decode the latest received signal, if the decoding is successful, the relay node R forwards the successfully decoded signal to the destination D with power P _R , and ends the transmission process; otherwise, directly End the transfer process.

Preferably, the power _PS is determined by a preset power allocation strategy and the power _PR is determined by the preset power allocation strategy, including:

Since the relay R works in full-duplex mode, at time slot t+1, the information signal x(t) forwarded by the relay R to the sink D will be received by the relay from the information signal x(t+1 ) to generate loop self-interference, thereby generating the coupling between the information signal and the self-interference signal, in order to balance the "information signal" and "interference signal", as well as "source-relay" and "relay-sink" The relationship between these two hops of transmission;

Set the transmit power PS of the source _S , and adaptively adjust the transmit power P _R of the full-duplex relay node R, so as to achieve the best energy efficiency EE of the system under the premise of reaching the target outage probability Excellent, where P _R ∈ [0, P _max ], P _max is the maximum transmission power that the full-duplex relay node R can achieve.

Preferably, the calculation method of the transmit power P _R is:

Depend on Obtain the corresponding P _R value when the energy efficiency EE of the system reaches the optimum as the target P _R value.

Preferably, the power _PS is determined by a preset power allocation strategy and the power _PR is determined by the preset power allocation strategy, including:

Since the relay R works in full-duplex mode, at time slot t+1, the information signal x(t) forwarded by the relay R to the sink D will be received by the relay from the information signal x(t+1 ) to generate loop self-interference, thereby generating the coupling between the information signal and the self-interference signal, in order to balance the "information signal" and "interference signal", as well as "source-relay" and "relay-sink" The relationship between these two hops of transmission;

Set the transmit power PS of the source _{S as P S =} αP, and set the transmit power of the full-duplex relay node R as P _R =(1-α)P, where P represents the system The total power consumption in each time slot, α represents the power allocation ratio.

Preferably, the calculation method of the α value is:

Depend on Find the corresponding α value when the energy efficiency EE of the system reaches the optimum as the target α value.

Preferably, the method for obtaining the energy efficiency EE of the system is:

For any time slot t, the probability π ₁ and failure probability π ₀ of the full-duplex relay node R successfully decoding the source signal x(t) are obtained: Wherein, P ₁₀ represents the probability of decoding failure at time slot t+1 when the full-duplex relay node R has loop self-interference, and P ₀₁ represents that the full-duplex relay node R does not have loop self-interference , the probability of successful decoding at time slot t+1;

The overall average outage probability P _out of the system is obtained from π ₀ and π ₁ : P _out = π ₀ + π ₁ (1-P _d ), where P _d indicates that the sink D can successfully decode the Probability of following a signal from node R;

The energy efficiency EE of the system is obtained from the overall average outage probability P _out of the system and the total power consumption P of the system in each time slot: Wherein, _EE represents the amount of data that can be successfully transmitted by consuming a unit of energy, and RT represents the rated data transmission rate of the signal of the source S.

Preferably, when the full-duplex relay node R exists loop self-interference, the probability P ₁₁ of successful decoding and the probability P ₁₀ of decoding failure of the signal x(t+1) at time slot t+1 are respectively :

When the full-duplex relay node R has no loop self-interference, the probability P ₀₁ of successful decoding of the signal x(t+1) at time slot t+1 and the probability P ₀₀ of decoding failure are respectively:

P ₀₁ ＝Pr{log ₂ (1+|g _S,R | ² P _S )≥R _T }

P ₀₀ ＝Pr{log ₂ (1+|g _S,R | ² P _S )<R _T }

Wherein, g _{S, R} is the channel gain from the source S to the full-duplex relay node R, g _{R, R} is the loop self-interference channel gain of the full-duplex relay node R, P _SI =P _R ^1-μ represents the power of the loop self-interference actually received by the full-duplex relay node R, 0<μ<1, and R _T is the rated data transmission rate of the signal of the source S.

Preferably, in step S4, the probability P _d that the sink D can successfully decode the signal from the full-duplex relay node R is: P _d =Pr{log ₂ (1+|gR _{, D} | ² P _R )≥R _T }, where g _R,D is the channel gain from the full-duplex relay node R to the destination D.

Preferably, P ₁₁ , P ₁₀ , P ₀₁ and P ₀₀ are obtained from the signal y _R (t+1) actually received by the full-duplex relay node R at time slot t+1, and P _d is obtained by the The signal y _D (t+1) received by the sink D at the time slot t+1 is obtained, where:

Considering the loop self-interference generated by the forwarded signal x(t) on the signal received by the full-duplex relay node R in time slot t+1, the signal actually received by the full-duplex relay node R y _R (t+1) is:

Wherein, n _R is the additive white Gaussian noise at the full-duplex relay node R, and n _D is the additive white Gaussian noise at the destination D.

According to another aspect of the present invention, a full-duplex relay system is provided, including: a source S, a sink D, and a full-duplex relay node R;

Wherein, the full-duplex relay node R is deployed between the source S and the sink D;

The full-duplex relay system is used to execute any one of the methods provided in the embodiments of the present invention.

Generally speaking, compared with the prior art scheme, the method of the present invention can achieve the following beneficial effects:

(1) The present invention reasonably allocates the transmission power of the source and the relay through the preset power allocation strategy, so as to achieve the purpose of improving the energy efficiency of the system under the condition of satisfying the target outage probability.

(2) The present invention can obtain the successful decoding probability in the "source-relay" steady state of each time slot, further obtain the interruption probability and energy efficiency of the system, and simplify the analysis and derivation process.

(3) An adaptive power allocation method for a full-duplex relay system proposed by the present invention, by adaptively adjusting the transmit power of the relay, reduces the mutual coupling effect between the relay information signal and the self-interference signal to the system Under the premise that the system reaches the target outage probability, unnecessary system energy consumption is reduced, and the energy efficiency of the system is optimized.

(4) The present invention proposes a joint source-relay power allocation method under the condition that the total power consumption of a full-duplex relay system is limited. Make full use of the mutual restriction between the two hop transmissions of "source-relay" and "relay-sink" due to the coupling between the information signal and the self-interference signal, under the premise that the total power consumption of the system is limited , reasonably allocate the transmit power of the source and the relay, and significantly improve the performance of the system.

Description of drawings

FIG. 1 is a schematic diagram of a model of a full-duplex relay system disclosed in an embodiment of the present invention;

FIG. 2 is a schematic flowchart of a communication method of a full-duplex relay system disclosed in an embodiment of the present invention;

3 is a schematic diagram of the relationship between relay transmission power and system outage probability under an adaptive power allocation method based on information-interference coupling characteristics;

4 is a schematic diagram of the relationship between relay transmission power and system energy efficiency under an adaptive power allocation method based on information-interference coupling characteristics;

5 is a schematic diagram of the relationship between the power allocation coefficient and the system outage probability under the joint source-relay power allocation method under the condition that the total power consumption of the system is limited;

6 is a schematic diagram of the relationship between the power allocation coefficient and the system energy efficiency under the joint source-relay power allocation method under the condition that the total power consumption of the system is limited.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

The invention discloses a communication method of a full-duplex relay system and a full-duplex relay system. When power distribution between a signal source and a full-duplex relay node, adaptive power control based on information-interference coupling characteristics is adopted method or a joint source-relay power allocation method under the condition that the total power consumption of the system is limited. In order to improve the communication quality between the source and the sink which are far apart, the present invention can effectively improve the frequency spectrum of the traditional half-duplex relay system by deploying a full-duplex relay node between the source and the sink to assist in forwarding the source signal. efficiency. Since the full-duplex relay node can receive and decode the new signal sent by the source of the current time slot while forwarding the source signal received in the previous time slot, the signal sent by the relay will cause a loop to the received signal Self-interference, which leads to the coupling between the two hop transmissions of "relay-sink" and "source-relay". On the one hand, if the transmission power of the full-duplex relay is too small, the communication quality of the "relay-sink" link will be damaged; on the other hand, if the transmission power of the relay node is too high, it is easy to cause too strong loop self-interference Then damage the communication quality of the "source-relay" link. In view of this, in order to balance the relationship between the two hop transmissions of "source-relay" and "relay-sink", and optimize the system energy efficiency under the premise of ensuring the predetermined communication quality, the present invention proposes a A joint source-relay power allocation method under constrained conditions and an adaptive power control method based on information-interference coupling characteristics. By properly allocating power between sources and relays, the system can significantly improve the energy efficiency of the system while meeting the target outage probability.

As shown in Figure 1, the system includes a source S, a sink D and a full-duplex relay node R. The relay R is deployed between the source S and the sink D, and the signal sent by the source needs to be transmitted to the sink through the two hops of "source-relay" and "relay-sink", which shortens the single-hop communication link distance , effectively improve the communication quality degradation caused by the long distance between the source S and the relay D or the poor channel conditions, and improve the communication quality and robustness of the system.

Since the relay node R works in the full-duplex state, the relay node R can receive and decode the new signal sent by the source at the current moment while forwarding the signal received in the previous time slot. Therefore, the signal sent by the relay will cause loop self-interference to the signal it receives, causing the coupling of the received signal and the forwarded signal.

At time slot t=1, source _S generates signal x(t) and sends x(t) to relay R with power PS, and R receives and decodes signal x(t);

In the time slot t=t+1, t≥1, the relay R sends the successfully decoded signal x(t) to the sink D with power P _R . At the same time, source _S generates a new signal x(t+1) and sends x(t+1) to relay R with power PS, and R receives and decodes signal x(t+1). Because the relay R works in a full-duplex mode, the signal sent by the relay will cause loop self-interference to the signal it receives, causing coupling between the received signal and the forwarded signal.

As shown in FIG. 2, it is a schematic flowchart of a communication method of a full-duplex relay system disclosed in an embodiment of the present invention. The method shown in FIG. 2 includes:

S1. At time slot t=1, source _S generates signal x(t), and sends signal x(t) to full-duplex relay node R with power PS, and full-duplex relay node R responds to signal x (t) receiving and decoding, wherein the power PS is _determined by a preset power allocation strategy;

S2. If the full-duplex relay node R can successfully decode, execute step S3, otherwise execute step S4;

S3. At time slot t+1, the full-duplex relay node R sends the decoded signal x(t) to the sink D with the power P _R , and at the same time, the source S sends the signal x(t) to the full-duplex relay node R with the power P _S The generated new signal x(t+1) is received and decoded by the full-duplex relay node R under the loop self-interference of the signal x(t), and then step S5 is performed, wherein , the power P _R is determined by the preset power allocation strategy;

In this time slot, the signals y' _R (t+1) and y _D (t+1) received by the sink D and the relay R are respectively:

Among them, g _{S, R} , g _{R, D} are the channel gains from source S to relay R, and from relay R to sink D, respectively, and g _{R, R} are the loop self-interference channel gains of relay node R. n _R , n _D are additive Gaussian white noise at relay R and destination D respectively.

The relay R can use the decoded signal x(t) as prior information to perform loop self-interference cancellation on the signal received by the relay R at time slot t+1. However, due to the near-far effect and the limitation of the actual system, the relay R cannot completely eliminate the loop self-interference, so the power of the actual loop self-interference received by the relay _R is defined as P _SI = PR ^1-μ , 0<μ<1 , where the larger the μ, the smaller the residual self-interference intensity; the smaller the μ, the greater the residual self-interference intensity. Therefore, the signal actually received by relay R is:

Since the relay R successfully decodes the signal x(t) sent by the source S at the time slot t, so at the time slot t+1, when the relay R receives the new signal x(t+1) sent by the source S , will be subject to loop self-interference generated by itself due to forwarding the signal x(t) to the destination D. Therefore, at time slot t+1, when relay R has loop self-interference, the probability P ₁₁ of successful decoding and the probability P ₁₀ of decoding failure are expressed as:

Among them, RT is the rated data transmission rate of the source signal _.

S4. At time slot t+1, the source _S sends the generated new signal x(t+1) to the full-duplex relay node R with the power PS, and the full-duplex relay node R responds to the signal x(t+ 1) receiving and decoding, and then performing step S5;

At time slot t+1, since relay R cannot successfully decode the signal x(t) sent by source S at time slot t, relay R only tries to receive and decode the new signal x(t+1) sent by source S ). Therefore, when the relay R has no loop self-interference, the probability P ₀₁ of successfully decoding the signal x(t+1) and the probability P ₀₀ of decoding failure can be expressed as:

P ₀₁ ＝Pr{log ₂ (1+|g _S,R | ² P _S )≥R _T }

P ₀₀ ＝Pr{log ₂ (1+|g _S,R | ² P _S )<R _T }

S5. Judging whether the signal transmission process is completed, if completed, execute step S6; otherwise, return to execute step S2;

S6. Judging whether the relay node R can successfully decode the latest received signal, if the decoding is successful, the relay node R forwards the successfully decoded signal to the destination D with power P _R , and ends the transmission process; otherwise, directly End the transfer process.

Wherein, because the distance between the source S and the sink D is relatively long or the channel quality is poor, the direct link between the "source-sink" is not considered in the present invention. Therefore, sink D is only interfered by additive white Gaussian noise when receiving the signal from relay R. Therefore, the probability P _d that the sink D can successfully decode the signal from the relay R is: P _d =Pr{log ₂ (1+|g _{R, D} | ² P _R )≥R _T }.

Preferably, the present invention provides two sources and relay power allocation methods, respectively:

Adaptive power allocation method based on information-interference coupling characteristics: Since the relay R works in full-duplex mode, at time slot t+1, the information signal x(t) forwarded by the relay to the destination D will receive from The information signal x(t+1) of the information source generates loop self-interference, thereby generating coupling between the information signal and the self-interference signal. On the one hand, if a higher relay transmission power is used, although the communication quality of the "relay-sink" link can be improved, the higher relay transmission power will bring more serious loop self-sufficiency to the relay R. interference. On the other hand, if a lower relay transmit power is used, although the loop self-interference effect of relay R can be reduced, the communication quality of the "relay-sink" link cannot be guaranteed. Therefore, after setting the transmission power PS of the source _S , an appropriate relay transmission power can be selected through the adaptive power control of the full-duplex relay to improve the overall performance of the system, wherein the set value of the transmission power _PS can be Determine according to actual needs.

The power of the transmitted signal of the relay R is denoted as P _R , and there exists P _R ∈ [0, P _max ], and P _max is the maximum transmission power that the relay R can achieve. By adaptively controlling the transmission power of the relay, the system reduces unnecessary system energy consumption and optimizes the energy efficiency of the system under the premise of reaching the target outage probability. The target outage probability can be determined according to actual needs.

Preferably, it can be done by Obtain the corresponding P _R value when the energy efficiency EE of the system reaches the optimum as the target P _R value.

Joint source-relay power allocation method under the condition of limited total system power consumption: Due to the coupling characteristics between the information signal and the self-interference signal, it will lead to the "source-relay" and "relay-sink" two The mutual restriction between hop transmission, so the setting of full-duplex relay R transmit power is very important. In order to balance the relationship between "information signal" and "interference signal", as well as the two-hop transmission of "source-relay" and "relay-sink", the patent proposes a full-duplex relay system Joint source-relay power allocation method under the condition of total power consumption constraint. The total power consumption of each time slot of the system is denoted as P, the power of the signal transmitted by the source S is denoted as P _S , and P _S =αP, then the transmit power of the relay R can be expressed as P _R =(1-α)P .

Then, by selecting an appropriate α value to configure the transmit power of the source and the relay, and then balancing the relationship between the two hop transmissions of "source-relay" and "relay-sink", the system can achieve Under the premise of target outage probability, unnecessary system energy consumption is reduced and energy efficiency of the system is optimized.

Preferably, it can be done by Find the corresponding α value when the energy efficiency EE of the system reaches the optimum as the target α value.

Consider any time slot t, define the success probability of relay decoding source signal x(t) as π ₁ , and the failure probability as π ₀ , then:

Then the overall average outage probability P _out of the system can be expressed as

P _out ＝π ₀ +π ₁ (1-P _d )

The energy efficiency EE of the system is defined as the amount of data that can be successfully transmitted by consuming a unit of energy, that is,

For the above two power setting methods, select the appropriate relay transmission power P _R or power distribution coefficient α, so that the system energy efficiency EE can reach the optimum, that is, under the condition that the total power consumption of the system is limited, the communication between the source and the relay The power distribution among them optimizes the energy efficiency of the system.

As shown in FIG. 3 , it is the relationship between relay transmission power and system outage probability under the adaptive power allocation method based on information-interference coupling characteristics. The transmit power of the signal source is 35dB. It can be seen from the figure that under the premise of a certain transmit power of the If the power is too small, the link quality of the "relay-sink" will be affected, and when the transmit power of the relay is too large, the transmit power of the relay forwarded signal will cause strong self-interference. Under the same source and relay transmission power, as the value of μ increases, the system outage probability shows a downward trend. This is because the larger the value of μ, the smaller the residual loop self-interference of the relay, so the system outage probability decreases . In addition, as the value of μ increases, the optimal relay transmission power shows an increasing trend, because the larger the value of μ, the smaller the residual self-interference of the relay forwarding signal to itself, that is, the "source-relay" The smaller the coupling between the two hops of the "relay-sink", the greater the gain of the "relay-sink" link by appropriately increasing the transmit power of the relay will be greater than the link in the "source-relay" Therefore, the optimal transmit power will show an upward trend as the value of μ increases.

As shown in FIG. 4 , it is the relationship between relay transmission power and system energy efficiency under the adaptive power allocation method based on information-interference coupling characteristics. The transmit power of the signal source is 35dB. It can be seen from the figure that, under the premise of a certain transmit power of the signal source, the energy efficiency of the system increases first and then decreases when the transmit power of the relay is continuously increased. The reason is the same as that in Figure 3. However, it can be seen from the figure that the optimal transmission power in Figure 4 will be significantly smaller than that in Figure 3. This is because when the system energy efficiency reaches the maximum, if the relay transmission power continues to increase, the system needs to increase a large amount of power consumption to bring a little probability of interruption Decline. In addition, as the value of μ increases, the energy efficiency of the system shows an upward trend.

As shown in Figure 5, it is the relationship between the power allocation coefficient and the system outage probability under the joint source-relay power allocation method under the condition that the total system power consumption is limited. It can be seen from the figure that under the condition that the total power consumption of the system is limited, the system will have an optimal power allocation coefficient to minimize the probability of system interruption. If the power allocation coefficient α is too large or too small, the probability of system interruption will increase. . This is because when α is too large, the transmission power allocated by the system to the relay is too small, which affects the communication quality of the "relay-sink" link. This is because when α is too small, the transmission power allocated by the system to the source is too small, which affects the communication quality of the "source-relay" link. The total power consumption of the system will also affect the setting of the power allocation coefficient α. When the total transmission power of the system increases, the optimal power allocation coefficient α will decrease accordingly, because increasing the transmission power of the relay will give the system "relay The improvement of the communication quality of the "-sink" link is far greater than the impact of the increase of relay self-interference on the communication quality of the "source-relay" link.

As shown in Figure 6, it is the relationship between the power allocation coefficient and the system capability efficiency under the joint source-relay power allocation method under the condition that the total system power consumption is limited. It can be seen from the figure that under the condition that the total power consumption of the system is limited, the system will have an optimal power allocation coefficient to maximize the system energy efficiency. When the power allocation coefficient α is too large or too small, the system energy efficiency will be reduced. Under the premise that the total power consumption of the system is constant, the system interruption probability is inversely proportional to the energy efficiency. It can also be seen from the figure that when the system power distribution coefficient is constant and the total power consumption of the system increases, the energy efficiency of the system does not necessarily increase.

It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (5)

1. A communication method of a full-duplex relay system, characterized in that, comprising: S1. At time slot t=1, the source _S generates a signal x(t), and sends the signal x(t) to the full-duplex relay node R with power PS, and the full-duplex relay node R performs the signal x(t) The signal x(t) is received and decoded, wherein the power PS is _determined by a preset power allocation strategy; S2. If the full-duplex relay node R can successfully decode, execute step S3, otherwise execute step S4; S3. At time slot t+1, the full-duplex relay node R sends a successfully decoded signal x(t) to the sink D with the power P _R , and at the same time, the source S sends the signal x(t) to the sink D with the power P _S The new signal x(t+1) generated by the full-duplex relay node R is sent, and the signal x(t+1) is performed by the full-duplex relay node R under the loop self-interference of the signal x(t). Receive and decode, and then perform step S5, wherein the power P _R is determined by the preset power allocation strategy; S4. At time slot t+1, the source _S sends the generated new signal x(t+1) to the full-duplex relay node R with the power PS, and the full-duplex relay The node R receives and decodes the signal x(t+1), and then performs step S5; S5. Determine whether the source signal transmission process is completed, if completed, execute step S6; otherwise, return to execute step S2; S6. Judging whether the relay node R can successfully decode the latest received signal, if the decoding is successful, the relay node R forwards the successfully decoded signal to the destination D with power P _R , and ends the transmission process; otherwise, directly end the transfer process; _Wherein , the power PS is determined by a preset power allocation strategy and the power _PR is determined by the preset power allocation strategy, including: Set the transmit power P _S of the source S, and by Obtain the P _R value corresponding to when the energy efficiency EE of the system reaches the optimum as the target P _R value, P _max is the maximum transmission power that the full-duplex relay node R can achieve; or, the information source S The transmission power P _S of the full-duplex relay node R is set as P _S =αP, and the transmission power of the full-duplex relay node R is set as P _R =(1-α)P, where P represents the total Power consumption, α represents the power distribution ratio, and the calculation method of α value is: by Find the corresponding α value when the energy efficiency EE of the system reaches the optimum as the target α value; Wherein, the method for obtaining the energy efficiency EE of the system is: For any time slot t, the probability π ₁ and failure probability π ₀ of the full-duplex relay node R successfully decoding the source signal x(t) are obtained: Wherein, P ₁₀ represents the probability of decoding failure at time slot t+1 when the full-duplex relay node R has loop self-interference, and P ₀₁ represents that the full-duplex relay node R does not have loop self-interference , the probability of successful decoding at time slot t+1; The overall average outage probability P _out of the system is obtained from π ₀ and π ₁ : P _out = π ₀ + π ₁ (1-P _d ), where P _d indicates that the sink D can successfully decode the Probability of following a signal from node R; The energy efficiency EE of the system is obtained from the overall average outage probability P _out of the system and the total power consumption P of the system in each time slot: Wherein, _EE represents the amount of data that can be successfully transmitted by consuming a unit of energy, and RT represents the rated data transmission rate of the signal of the source S. 2. The method according to claim 1, wherein the full-duplex relay node R can successfully decode the signal x(t+1) at time slot t+1 when there is loop self-interference The probability P ₁₁ and the probability P ₁₀ of decoding failure are respectively <mrow><msub><mi>P</mi><mn>11</mn></msub><mo>=</mo><mi>Pr</mi><mo>{</mo><msub><mi>log</mi><mn>2</mn></msub><mrow><mo>(</mo><mn>1</mn><mo>+</mo><mfrac><mrow><msup><mrow><mo>|</mo><msub><mi>g</mi><mrow><mi>S</mi><mo>,</mo><mi>R</mi></mrow></msub><mo>|</mo></mrow><mn>2</mn></msup><msub><mi>P</mi><mi>S</mi></msub></mrow><mrow><msup><mrow><mo>|</mo><msub><mi>g</mi><mrow><mi>R</mi><mo>,</mo><mi>R</mi></mrow></msub><mo>|</mo></mrow><mn>2</mn></msup><msub><mi>P</mi><mrow><mi>S</mi><mi>I</mi></mrow></msub><mo>+</mo><mn>1</mn></mrow></mfrac><mo>)</mo></mrow><mo>&amp;GreaterEqual;</mo><msub><mi>R</mi><mi>T</mi></msub><mo>}</mo></mrow> <mrow><msub><mi>P</mi><mn>10</mn></msub><mo>=</mo><mn>1</mn><mo>-</mo><msub><mi>P</mi><mn>11</mn></msub><mo>=</mo><mn>1</mn><mo>-</mo><mi>Pr</mi><mo>{</mo><msub><mi>log</mi><mn>2</mn></msub><mrow><mo>(</mo><mn>1</mn><mo>+</mo><mfrac><mrow><msup><mrow><mo>|</mo><msub><mi>g</mi><mrow><mi>S</mi><mo>,</mo><mi>R</mi></mrow></msub><mo>|</mo></mrow><mn>2</mn></msup><msub><mi>P</mi><mi>S</mi></msub></mrow><mrow><msup><mrow><mo>|</mo><msub><mi>g</mi><mrow><mi>R</mi><mo>,</mo><mi>R</mi></mrow></msub><mo>|</mo></mrow><mn>2</mn></msup><msub><mi>P</mi><mrow><mi>S</mi><mi>I</mi></mrow></msub><mo>+</mo><mn>1</mn></mrow></mfrac><mo>)</mo></mrow><mo>&amp;GreaterEqual;</mo><msub><mi>R</mi><mi>T</mi></msub><mo>}</mo></mrow> When the full-duplex relay node R has no loop self-interference, the probability P ₀₁ of successful decoding of the signal x(t+1) at time slot t+1 and the probability P ₀₀ of decoding failure are respectively: P ₀₁ ＝Pr{log ₂ (1+|g _S,R | ² P _S )≥R _T } P ₀₀ ＝Pr{log ₂ (1+|g _S,R | ² P _S )<R _T } Wherein, g _{S, R} is the channel gain from the source S to the full-duplex relay node R, g _{R, R} is the loop self-interference channel gain of the full-duplex relay node R, P _SI =P _R ^1-μ represents the power of the loop self-interference actually received by the full-duplex relay node R, 0<μ<1, and R _T is the rated data transmission rate of the signal of the source S. 3. The method according to claim 2, characterized in that, the probability P _d of the signal sink D being able to successfully decode the signal from the full-duplex relay node R is: P _d =Pr{log ₂ (1+ |g _R,D | ² P _R )≥R _T }, where g _R,D is the channel gain from the full-duplex relay node R to the destination D. 4. The method according to claim 3, characterized in that P ₁₁ , P ₁₀ , P ₀₁ and P ₀₀ are signals y _R (t +1) Obtained, P _d is obtained by obtaining the signal y _D (t+1) received by the sink D at time slot t+1, wherein: <mrow><msub><mi>y</mi><mi>D</mi></msub><mrow><mo>(</mo><mi>t</mi><mo>+</mo><mn>1</mn><mo>)</mo></mrow><mo>=</mo><msub><mi>g</mi><mrow><mi>R</mi><mo>,</mo><mi>D</mi></mrow></msub><msqrt><msub><mi>P</mi><mi>R</mi></msub></msqrt><mi>x</mi><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow><mo>+</mo><msub><mi>n</mi><mi>D</mi></msub><mrow><mo>(</mo><mi>t</mi><mo>+</mo><mn>1</mn><mo>)</mo></mrow><mo>;</mo></mrow> Considering the loop self-interference generated by the forwarded signal x(t) on the destination received signal x(t+1) of the full-duplex relay node R in time slot t+1, therefore, the full-duplex relay The signal y _R (t+1) actually received by node R is: Wherein, n _R is the additive white Gaussian noise at the full-duplex relay node R, and n _D is the additive white Gaussian noise at the destination D. 5. A full-duplex relay system, comprising: a source S, a sink D and a full-duplex relay node R; Wherein, the full-duplex relay node R is deployed between the source S and the sink D; The full-duplex relay system is used to implement the method according to any one of claims 1-4.