CN116017372A

CN116017372A - Communication method and communication device

Info

Publication number: CN116017372A
Application number: CN202111236323.7A
Authority: CN
Inventors: 龙航; 黄莉; 张露元; 刘梦婷
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-10-22
Filing date: 2021-10-22
Publication date: 2023-04-25

Abstract

A communication method and a communication apparatus are provided. The method comprises the following steps: the relay node receives a first signal, wherein the first signal comprises a first modulation symbol from a first source node and a second modulation symbol from a second source node, the first modulation symbol comprises symbols mapped on a first constellation diagram, a plurality of constellation points in the same quadrant in the first constellation diagram, the minimum distance between two adjacent constellation points in the same quadrant is smaller than 2k, k is a constellation mapping normalization factor, the second modulation symbol comprises symbols mapped on a second constellation diagram, the constellation points in each quadrant in the second constellation diagram are not more than one, and the transmitting power of the second modulation symbol is determined according to the transmitting power of the first modulation symbol; the relay node then forwards the first signal. The bit error rate of the first signal received by the relay node is improved by reducing the distance between adjacent constellation points in the same quadrant and redetermining the transmitting power, so that interception of information by the relay node is avoided to a great extent.

Description

Communication method and communication device

Technical Field

The present application relates to the field of communications, and more particularly, to a communication method and a communication apparatus.

Background

With the development of communication technology, a bidirectional relay system that uses two source nodes to exchange information via a relay node is being studied more and more because it can save information transmission time slots and increase communication transmission rate. In the process of communication between source nodes, the relay node may eavesdrop on the transmission information, resulting in information leakage. Therefore, secure communication of the bidirectional relay system becomes a new concern.

At present, a signal sent by a source node is generally designed by utilizing precoding and cooperative interference technology, so that the safe transmission rate in the communication process is improved. However, this method generally assumes that the signal is a gaussian signal, which is difficult to put into practical use in actual communication. Even though few researches consider a specific modulation mode of signals, the phase and power of signals of a common modulation mode are designed according to channel state information, so that signals sent by two source nodes form superposition of signals at a relay node, interception of the relay node is prevented with small probability, and the mode still has the risk of information leakage. Therefore, how to realize practical signal design to avoid information leakage to a great extent is a technical problem to be solved urgently.

Disclosure of Invention

The embodiment of the application provides a communication method and a communication device, which aim to realize that information leakage is avoided to a great extent by a practical signal design.

In a first aspect, the present application provides a communication method, where the method may be performed by a relay node, or may also be performed by a component (such as a chip, a system on a chip, etc.) configured in the relay node, or may also be implemented by a logic module or software capable of implementing all or part of the functions of the relay node, which is not limited in this application.

Illustratively, the method includes: the relay node receives a first signal comprising a first modulation symbol from a first source node and a second modulation symbol from a second source node; the first modulation symbol comprises symbols mapped on a first constellation diagram, a plurality of constellation points are arranged in the same quadrant in the first constellation diagram, the minimum distance between two adjacent constellation points in the same quadrant is smaller than 2k, and k is a constellation mapping normalization factor; the second modulation symbol comprises symbols mapped on a second constellation diagram, wherein no more than one constellation point is arranged in each quadrant in the second constellation diagram, and the transmitting power of the second modulation symbol is determined according to the transmitting power of the first modulation symbol; the relay node forwards the first signal.

Wherein the constellation mapping normalization factor may be determined by: and after the energy sum of all constellation points in the constellation diagram is averaged, the energy sum is squared to obtain a waveform amplitude value, and the inverse of the waveform amplitude value is taken to obtain a constellation mapping normalization factor. Wherein the energy of the constellation point may be determined by: the sum of the squares of the abscissa and the squares of the ordinate of the constellation points in the constellation.

Wherein the transmit power of the second modulation symbol is determined according to the transmit power of the first modulation symbol, further comprising: the transmit power of the second modulation symbol is determined based on the predefined target amplitude ratio and the transmit power of the first modulation symbol. Wherein the value of the target amplitude ratio is smaller than

At the same time, can approach a with larger value ₀ 。a ₀ Is determined by the following formula: />

Wherein a is ₀ The point where the reception performance of the second source node is optimal is satisfied, SNR is a signal-to-noise ratio, and N is a value that ensures that the bit error rate of the signal received at the relay node approaches 0.5.

Based on the technical content, in the first signal received by the relay node, the first modulation symbol in the first signal is a symbol mapped on the first constellation diagram, and the minimum distance between two adjacent constellation points in the same quadrant in the first constellation diagram is smaller than 2k, so that the distance between two adjacent constellation points in the same quadrant is shortened, the symbol error rate of the signal received by the relay node is increased, the bit error rate is indirectly improved, and the probability of eavesdropping on the information of the first modulation symbol by the relay node is reduced. The transmitting power of the second modulation symbol in the first signal is redetermined according to the predefined target amplitude ratio and the transmitting power of the first modulation symbol, so that the determined transmitting power of the second modulation symbol can also reduce the probability of eavesdropping on the information of the second modulation symbol by the relay node to a certain extent. When the first modulation symbol and the second modulation symbol are simultaneously overlapped at the relay node, the probability of information interception by the relay node can be greatly reduced, and information leakage is avoided. The generation method of the modulation symbol is not a theoretical modulation method, and the signal design can be put into practical use.

With reference to the first aspect, in certain possible implementation manners of the first aspect, the method further includes: the relay node sends first channel information to the first source node, wherein the first channel information is used for indicating the amplitude value of the second channel and the noise power at the relay node; or, the first channel information is used to indicate the amplitude ratio of the second channel to the first channel, and the ratio of the square of the amplitude of the first channel to the noise power at the relay node; the first channel is a channel between the first source node and the relay node, and the second channel is a channel between the second source node and the relay node.

The relay node sends the relevant parameters to the first source node, so that the first source node can conveniently and quickly determine a signal-to-noise ratio (SNR) and an amplitude ratio a.

With reference to the first aspect, in certain possible implementation manners of the first aspect, the method further includes: the relay node receives a first request from a first source node, the first request requesting first channel information.

With reference to the first aspect, in certain possible implementation manners of the first aspect, the method further includes: the relay node sends second channel information to a second source node, wherein the second channel information is used for indicating the amplitude value of the first channel and the phase of the first channel; or, the amplitude ratio and the phase difference of the second channel and the first channel; the first channel is a channel between the first source node and the relay node, and the second channel is a channel between the second source node and the relay node.

And the relay node sends the related parameters to the second source node, so that the second source node can conveniently and quickly determine the amplitude ratio a and the phase difference delta theta.

With reference to the first aspect, in certain possible implementation manners of the first aspect, the method further includes: the relay node receives a second request from a second source node, the second request requesting second channel information.

With reference to the first aspect, in some possible implementations of the first aspect, a minimum distance between two adjacent constellation points in the same quadrant is (2-2 c) k,0 < c < 1.

By introducing the parameter c into the first constellation diagram, the distance between two adjacent constellation points in the same quadrant is shortened, so that the symbol error rate of a signal received by the relay node is increased, the bit error rate is indirectly improved, and the probability of eavesdropping on the information of the first modulation symbol by the relay node is reduced.

With reference to the first aspect, in some possible implementations of the first aspect, the parameter c is determined by the parameter N, SNR and the amplitude ratio a; wherein the value of the parameter N makes the difference between the target bit error rate and 0.5 not larger than Q (N)/2, and Q (N) is a right tail function of standard normal distribution; the SNR is the SNR of the first channel and the amplitude ratio a is the ratio of the amplitude of the second channel to the amplitude of the second modulation symbol and the amplitude of the first channel to the amplitude of the first modulation symbol.

It should be appreciated that the target bit error rate is the expected bit error rate of the signal received at the relay node, which when it takes a certain value, can ensure that the difference from 0.5 does not exceed 0.1, and can be considered that the relay node can hardly eavesdrop on any information. While the difference between the desired bit error rate and 0.5 may be represented by Q (N)/2. That is, when Q (N)/2.ltoreq.0.1, that is Q (N). Ltoreq.0.2, almost no information is eavesdropped at the relay node. And Q (N) is the right-tail function of the normal distribution, the inverse function Q of reference Q (N) ^-1 As can be seen from the curve of (N), Q ^-1 (0.2) ≡ 0.8416, i.e., Q (0.8416) ≡0.2. That is, when the parameter N > 0.8416, it can be ensured that the difference between the target bit error rate and 0.5 is not more than 0.1, and the information is hardly intercepted at the relay node.

By associating the determination of the parameter c with the parameter N, the difference between the target bit error rate and 0.5 is not greater than Q (N)/2, so that the bit error rate of the signal received by the relay node tends to 0.5 after the parameter c is introduced, almost no information is intercepted by the relay node, and information leakage is completely avoided.

With reference to the first aspect, in some possible implementations of the first aspect, the determining manner of the parameter c is related to a modulation manner of the first modulation symbol.

With reference to the first aspect, in some possible implementations of the first aspect, the bit sequence corresponding to each constellation point in the first constellation is obtained based on non-gray code encoding.

By adopting non-Gray code coding for the bit sequence corresponding to each constellation point in the first constellation diagram, the probability of bit transmission errors is improved, so that the bit error rate of signals received by the relay node is further improved, and the risk of information leakage is further avoided.

With reference to the first aspect, in some possible implementations of the first aspect, the correspondence between the plurality of constellation points in the first constellation and the bit sequence is determined based on one of a predefined plurality of coding modes; the bit sequence comprises four bits, in each of the multiple coding modes, each constellation point corresponds to the first two bits of the bit sequence on the in-phase component I axis, and each constellation point corresponds to the second two bits of the bit sequence on the quadrature component Q axis; in any two coding modes of the multiple coding modes, the sequences of the bits corresponding to the constellation points on the I axis are different, and/or the sequences of the bits corresponding to the constellation points on the Q axis are different.

By predefining a plurality of coding modes, in actual coding, any coding mode can be adopted to determine the corresponding relation between a plurality of constellation points in the first constellation diagram and the bit sequence, and the flexibility of the coding mode is improved.

With reference to the first aspect, in some possible implementations of the first aspect, the first modulation symbol is modulated based on a quadrature amplitude (quadrature amplitude modulation, QAM) modulation scheme.

With reference to the first aspect, in some possible implementations of the first aspect, the second modulation symbol is modulated based on a quadrature phase shift keying (quadrature phase shift keying, QPSK) modulation scheme or a binary phase shift keying (binary phase shift keying, BPSK) modulation scheme.

With reference to the first aspect, in some possible implementations of the first aspect, the phase of the second modulation symbol is determined by a phase difference between a second channel and a first channel, where the first channel is a channel between the first source node and the relay node, and the second channel is a channel between the second source node and the relay node.

Optionally, the second modulation symbol is based on quadrature phase shift keying modulation mode, and the phase θ of the second modulation symbol _S2 Phase difference from the phase difference delta theta

Is an integer multiple of (a).

Illustratively, the phase θ of the second modulation symbol _S2 And the phase difference delta theta:

l is an integer.

Optionally, the second modulation symbol is based on a binary phase shift keying modulation mode, and the phase θ of the second modulation symbol _S2 Phase difference from the phase difference delta theta

Odd multiples of (2).

l is an integer.

The phase of the second modulation symbol is adjusted according to the channel phase difference, so that the first modulation symbol and the second modulation symbol can be aligned, and the probability of information interception by the relay node can be further reduced. And considering the periodicity of the signals, the phases of the first modulation symbol and the second modulation symbol of each period are aligned, so that the signals of each period received by the relay node can be ensured to reduce the risk of information leakage.

In a second aspect, the present application provides a communication method, where the method may be performed by the first source node, or may also be performed by a component (such as a chip, a system on a chip, etc.) configured in the first source node, or may also be implemented by a logic module or software capable of implementing all or part of the functions of the first source node, where the application is not limited to this.

Illustratively, the method includes: the first source node generates a first modulation symbol, wherein the first modulation symbol comprises symbols mapped on a first constellation diagram, a plurality of constellation points are arranged in the same quadrant in the first constellation diagram, the minimum distance between two adjacent constellation points in the same quadrant is smaller than 2k, and k is a constellation mapping normalization factor; the first source node sends the first modulation symbol to the relay node.

Based on the technical content, the first modulation symbol generated by the first source node is a symbol mapped on the first constellation diagram, the minimum distance between two adjacent constellation points in the same quadrant in the first constellation diagram is smaller than 2k, the distance between two adjacent constellation points in the same quadrant is shortened, the distance between two adjacent constellation points can affect the symbol error rate of the first modulation symbol received at the relay node, the smaller the distance is, the larger the probability of symbol transmission error is, the larger the symbol error rate is, the probability of bit transmission error is increased, and the bit error rate of the signal received at the relay node is increased, so that the risk of information eavesdropping is reduced.

With reference to the second aspect, in certain possible implementations of the second aspect, the method further includes: the first source node receives first channel information indicating an amplitude of the second channel and a noise power at the relay node; or, the first channel information is used to indicate the amplitude ratio of the second channel to the first channel, and the ratio of the square of the amplitude of the first channel to the noise power at the relay node; the first channel is a channel between the first source node and the relay node, and the second channel is a channel between the second source node and the relay node.

With reference to the second aspect, in certain possible implementations of the second aspect, the method further includes: the first source node sends a first request to the relay node, the first request requesting first channel information.

With reference to the second aspect, in some possible implementations of the second aspect, the parameter c is determined by a parameter N, SNR and an amplitude ratio a; wherein the value of the parameter N makes the difference between the target bit error rate and 0.5 not larger than Q (N)/2, and Q (N) is a right tail function of standard normal distribution; the SNR is the SNR of the first channel and the amplitude ratio a is the ratio of the amplitude of the second channel to the amplitude of the second modulation symbol and the amplitude of the first channel to the amplitude of the first modulation symbol.

With reference to the second aspect, in some possible implementations of the second aspect, the determining manner of the parameter c is related to a modulation manner of the first modulation symbol.

With reference to the second aspect, in some possible implementations of the second aspect, the bit sequence corresponding to each constellation point in the first constellation map is obtained based on non-gray code encoding.

With reference to the second aspect, in some possible implementations of the second aspect, the correspondence between the plurality of constellation points in the first constellation and the bit sequence is determined based on one of a predefined plurality of coding modes; the bit sequence comprises four bits, in each of the multiple coding modes, each constellation point corresponds to the first two bits of the bit sequence on the in-phase component I axis, and each constellation point corresponds to the second two bits of the bit sequence on the quadrature component Q axis; in any two coding modes of the multiple coding modes, the sequences of the bits corresponding to the constellation points on the I axis are different, and/or the sequences of the bits corresponding to the constellation points on the Q axis are different.

With reference to the second aspect, in some possible implementations of the second aspect, the first modulation symbol is modulated based on a quadrature amplitude modulation mode.

In a third aspect, the present application provides a communication method, where the method may be performed by the second source node, or may also be performed by a component (such as a chip, a system on a chip, etc.) configured in the second source node, or may also be implemented by a logic module or software capable of implementing all or part of the functions of the second source node, where the application is not limited to this.

Illustratively, the method includes: the second source node generates a second modulation symbol, wherein the second modulation symbol comprises symbols mapped on a second constellation diagram, no more than one constellation point is arranged in each quadrant in the second constellation diagram, and the transmitting power of the second modulation symbol is determined according to the transmitting power of the first modulation symbol; the second source node sends the second modulation symbol to the relay node.

Wherein the transmit power of the second modulation symbol is determined according to the transmit power of the first modulation symbol, further comprising: the transmission power of the second modulation symbol is according to a predefined target amplitude ratio and the first modulation symbolIs provided. Wherein the value of the target amplitude ratio is smaller than

At the same time, can approach a with larger value ₀ 。a ₀ Is determined by the following formula:

Based on the technical content, the second modulation symbol generated by the second source node is a symbol mapped on the second constellation diagram, and the transmitting power of the second modulation symbol is determined according to the predefined target amplitude ratio and the transmitting power of the first modulation symbol, and the predefined target amplitude ratio can ensure the requirement of the anti-eavesdrop performance at the relay node and the receiving performance of the source node, so that the obtained transmitting power of the second modulation symbol can also ensure the requirement of the anti-eavesdrop performance at the relay node and the receiving performance of the source node, thereby being beneficial to reducing the probability of the relay node eavesdrop on the information of the second modulation symbol.

With reference to the third aspect, in some possible implementations of the third aspect, the method further includes: the second source node receives second channel information, wherein the second channel information is used for indicating the amplitude value of the first channel and the phase of the first channel; or, the amplitude ratio and the phase difference of the second channel and the first channel; the first channel is a channel between the first source node and the relay node, and the second channel is a channel between the second source node and the relay node.

With reference to the third aspect, in some possible implementations of the third aspect, the method further includes: the second source node sends a second request to the relay node, the second request requesting second channel information.

With reference to the third aspect, in some possible implementations of the third aspect, the second modulation symbol is modulated based on a quadrature phase shift keying modulation scheme or a binary phase shift keying modulation scheme.

With reference to the third aspect, in some possible implementations of the third aspect, the phase of the second modulation symbol is determined by a phase difference between a second channel and a first channel, where the first channel is a channel between the first source node and the relay node, and the second channel is a channel between the second source node and the relay node.

Is an integer multiple of (a).

l is an integer.

Is an odd multiple of l is an integer.

l is an integer.

In a fourth aspect, the present application provides a communication device comprising means or units for implementing the method of the first to third aspects and any one of the possible implementations of the first to third aspects. It will be understood that each module or unit may implement a corresponding function by executing a computer program.

In a fifth aspect, the present application provides a communication device comprising a processor for performing the communication method of the first to third aspects and any one of the possible implementation manners of the first to third aspects.

The apparatus may also include a memory to store instructions and data. The memory is coupled to the processor, which when executing instructions stored in the memory, can implement the methods described in the above aspects. The apparatus may also include a communication interface for the apparatus to communicate with other devices, which may be, for example, a transceiver, circuit, bus, module, or other type of communication interface.

In a sixth aspect, the present application provides a computer readable storage medium comprising a computer program which, when run on a computer, causes the computer to implement the method of the first to third aspects and any one of the possible implementations of the first to third aspects.

In a seventh aspect, the present application provides a computer program product comprising: a computer program (which may also be referred to as code, or instructions) which, when executed, causes a computer to perform the methods of the first to third aspects and any one of the possible implementations of the first to third aspects.

It should be understood that, the fourth to seventh aspects of the present application correspond to the technical solutions of the first to third aspects of the present application, and the advantages obtained by each aspect and the corresponding possible embodiments are similar, and are not repeated.

Drawings

Fig. 1 is a schematic view of a scenario of a communication method provided in an embodiment of the present application;

fig. 2 is another schematic view of a communication method according to an embodiment of the present application;

fig. 3 is a scene architecture diagram of a communication method provided in an embodiment of the present application;

FIG. 4 is a schematic flow chart of a communication method provided by an embodiment of the present application;

fig. 5 is a 16QAM constellation provided in an embodiment of the present application;

fig. 6 is a 16QAM non-gray code encoding constellation provided in an embodiment of the present application;

fig. 7 is a QPSK constellation provided in an embodiment of the present application;

FIG. 8 is a simulation diagram of Bit Error Rate (BER) at a relay node in a vehicle-to-vehicle (vehicle to vehicle, V2V) scenario provided by an embodiment of the present application;

FIG. 9 is a simulation diagram of BER at a source node in a V2V scenario provided by an embodiment of the present application;

fig. 10 is a simulation diagram of BER at a relay node in a satellite mobile communication scenario provided in an embodiment of the present application;

FIG. 11 is a simulation diagram of BER at a source node in a satellite mobile communication scenario provided by an embodiment of the present application;

Fig. 12 to 14 are schematic block diagrams of a communication apparatus provided in an embodiment of the present application.

Detailed Description

The technical solutions in the present application will be described below with reference to the accompanying drawings.

The technical scheme provided by the application can be applied to various communication systems, such as: fifth generation (5th generation,5G) mobile communication systems or new radio access technologies (new radio access technology, NR). The 5G mobile communication system may include a non-independent Networking (NSA) and/or an independent networking (SA), among others.

The technical solutions provided herein may also be applied to machine-type communication (machine type communication, MTC), inter-machine communication long term evolution technology (long term evolution-machine, LTE-M), device-to-device (D2D) networks, machine-to-machine (machine to machine, M2M) networks, internet of things (internet of things, ioT) networks, or other networks. The IoT network may include, for example, an internet of vehicles. The communication manner in the internet of vehicles system is generally called as a vehicle to other device (V2X, X may represent anything) system, for example, the V2X may include: vehicle-to-vehicle (vehicle to vehicle, V2V) communication, vehicle-to-infrastructure (vehicle to infrastructure, V2I) communication, vehicle-to-pedestrian communication (vehicle to pedestrian, V2P) or vehicle-to-network (vehicle to network, V2N) communication, etc. But also to communication between satellites.

The technical scheme provided by the application can also be applied to future communication systems, such as a sixth generation mobile communication system and the like. The present application is not limited in this regard.

Fig. 1 is a schematic view of a scenario suitable for a communication method provided in an embodiment of the present application. As shown in fig. 1, a V2V communication scenario is illustrated. In this communication scenario, there are included a vehicle 101, a vehicle 102, a vehicle 103, and a vehicle 104, and an air-moving relay 105. When the distance between any two vehicles is far, information exchange can be performed through the air mobile relay. For example, the vehicle 101 and the vehicle 104 can exchange information through the air-moving relay 105, and the vehicle 102 and the vehicle 103 can also exchange information through the air-moving relay 105.

It should be understood that fig. 1 is only an example, showing one air movement relay and four vehicles. But this should not constitute any limitation to the present application. More or fewer vehicles can be included in the V2V scene, and more air mobile relays can be included. The embodiments of the present application are not limited in this regard.

Fig. 2 is another schematic view of a communication method according to an embodiment of the present application. As shown in fig. 2, a satellite mobile communication scenario is illustrated. In this scenario, there are included an earth station 201, an earth station 202, and an artificial earth satellite 203. Since the distance between the earth station 201 and the earth station 202 is long in the space, the earth station 201 and the earth station 202 can exchange information via the artificial map satellite 203.

It should be understood that fig. 2 is also merely an example, showing one artificial earth satellite and two earth stations. But this should not constitute any limitation to the present application. The satellite mobile communication scene can also comprise more earth stations and more artificial earth satellites. The embodiments of the present application are not limited in this regard.

It should be understood that the relay selection in the present application is not limited to the air mobile relay in fig. 1, or the satellite in fig. 2, but may also be a terrestrial relay, and all the third party nodes capable of playing a role in forwarding information may be used as relays. The embodiments of the present application are not limited in this regard.

For the scenario shown in fig. 1 and 2, both may be equivalent to the scenario architecture of fig. 3. The following is a detailed description with reference to fig. 3.

Fig. 3 is a scene structure diagram of a communication method according to an embodiment of the present application. As shown in FIG. 3, S ₁ Is a source node S ₂ R is a relay node, which is another source node. h is a _S1R As the source node S ₁ Channel to R direction of relay node, h _S2R As the source node S ₂ Channel to R direction of relay node, h _RS1 For the relay node R to the source node S ₁ Directional channel, h _RS2 For the relay node R to the source node S ₂ Channel in direction x _S1 As the source node S ₁ Transmitted useful signal x _S2 As the source node S ₂ The transmitted useful signal.

During communication, the source node S ₁ And source node S ₂ Information exchange can be performed through the relay node R, and the relay node R is used as a source node S ₁ And source node S ₂ And the bridge is used for assisting in forwarding signals. The relay node R may be a trusted node, and does not eavesdrop on the received signal; and possibly an untrusted node, may tap the received signal. It should be understood that when the relay node R is an untrusted node, it may be a communication node with a lower security level that can normally operate, and may perform a communication function normally, but may eavesdrop on a received signal, and may not be tampered with maliciously, and is not a malicious active attacker.

It should be appreciated that in the V2V scenario shown in fig. 1, the over-the-air mobile relay 105 may act as the relay node R in fig. 3. For any two vehicles, one of the vehicles may serve as the source node S in FIG. 3 ₁ Another vehicle may serve as the source node S ₂ For example, the vehicle 101 may serve as the source node S ₁ The vehicle 104 may act as a source node S ₂ 。

It should also be appreciated that in the satellite mobile communications scenario illustrated in fig. 2, the artificial earth satellite 203 may act as the relay node R in fig. 3. Either of the earth station 201 and the earth station 202 may serve as the source node S in fig. 3 ₁ Another one can be used as a source node S ₂ For example, the earth station 201 may act as a source node S ₁ The earth station 202 may act as a source node S ₂ 。

Further, as shown in fig. 3, in this scenario architecture, the communication process may be divided into two phases, and the communication process is specifically described below.

In the first stage, the source node sends a signal to the relay node: s is S ₁ And S is ₂ Send a signal to R, S ₁ Transmitting useful signal x _S1 ，S ₂ Transmitting useful signal x _S2 The relay node R receives the signal y _R The method comprises the following steps:

wherein P is _S1 And P _S2 Respectively are source nodes S ₁ Signal transmission power, S ₂ Signal transmission power n of (2) _R Is the noise at R. And, as previously described, h _S1R As the source node S ₁ Channel to R direction of relay node, h _S2R As the source node S ₂ Channel to R direction of relay node, x _S1 As the source node S ₁ Transmitted useful signal x _S2 As the source node S ₂ The transmitted useful signal.

Wherein x is _S1 And x _S2 Respectively satisfy the conditions of

E is the desired value, ->

Is x _S1 Conjugate transpose of->

Is x _S2 Is a conjugate transpose of (a).

Wherein n is _R Also satisfy the condition n _R ～CN(0，σ ² ) CN is complex Gaussian distribution, sigma ² The variance is the noise power at the relay node R.

It should be appreciated that the signal received at the relay node R is a mixed signal comprising the source node S ₁ Transmitted useful signal and source node S ₂ The transmitted useful signal.

It should also be appreciated that the source node S, when not considering information transmission delay ₁ And source node S ₂ Simultaneously transmitting signals to the relay node R to ensure that the relay node R can simultaneously receive S ₁ Transmitted useful signal and S ₂ The transmitted useful signal.

And in the second stage, the relay node forwards signals: receiving signal y at relay node _R After that, the relay node R pairs the signal y _R Amplifying or reducing to obtain the signal x to be forwarded _R The method comprises the following steps:

x _R ＝βy _R

wherein beta is a power limiting coefficient, x _R Needs to meet the condition

E is the desired value, ->

Is x _R P is the conjugate transpose of (2) _R Is the transmit power of the relay node R.

It should be understood that the specific value of the power limiting coefficient β depends on the transmission power P of the relay node R _R Is only required to satisfy the magnitude of the signal y _R The signal x obtained after the adjustment _R Is set to P _R And (3) obtaining the product.

Obtaining a signal x needing to be forwarded at a relay node R _R After that, the signal x can be applied _R Respectively forwarded to source node S ₁ And source node S ₂ Then the source node S ₁ And source node S ₂ The received signals are respectively full ofFoot:

y _S1 ＝h _RS1 x _R +n _S1

and

y _S2 ＝h _RS2 x _R +n _S2

wherein y is _S1 As the source node S ₁ Received signal, y _S2 As the source node S ₂ A received signal. n is n _S1 As the source node S ₁ Noise at n _S2 As the source node S ₂ Noise at the location.

At the source node S ₁ And source node S ₂ Respectively receive the signals y _S1 And y _S2 After that, the source node S ₁ The useful signal x can be processed by self-interference cancellation techniques _S1 Deleting, thereby obtaining the source node S ₂ Transmitted useful signal x _S2 . Accordingly, the source node S ₂ The useful signal x can also be processed by self-interference cancellation techniques _S2 Deleting, thereby obtaining the source node S ₁ Transmitted useful signal x _S1 . It should be noted that the self-interference cancellation technique is the prior art, and will not be described here.

It is known that, since the signal obtained by the source node through the self-interference cancellation technique does not include the useful signal transmitted by itself, the useful signal does not affect the reception performance of the source node no matter what modulation scheme is adopted for the useful signal transmitted by the source node.

It should be understood that fig. 3 is also merely an example, showing one relay node and two source nodes. But this should not constitute any limitation to the present application. More relay nodes can be included in the scene, and more source nodes can be included. The embodiments of the present application are not limited in this regard.

As described above, in order to realize secure communication in the bidirectional relay system, a signal transmitted from a source node is designed based on a gaussian signal to improve a secure transmission rate. Even if the phase and power of the common modulation scheme signal are designed by using the channel state information in a small part of researches, the method can only prevent the relay node from eavesdropping on the information with a small probability. That is, in the current research, it is not possible to reduce the risk of interception of information to a great extent in a practical signal design manner.

In view of this, the present application provides a communication method, in which, before a first source node and a second source node send respective signals, the respective signals are modulated, so as to obtain a first modulation symbol and a second modulation symbol, respectively. The first modulation symbol comprises symbols mapped on a first constellation diagram, a plurality of constellation points in the same quadrant in the first constellation diagram, and the minimum distance between two adjacent constellation points in the same quadrant is smaller than 2k, wherein k is a constellation mapping normalization factor. Since the distance between two adjacent constellation points is shortened, the bit error rate at the relay node can be indirectly improved. The second modulation symbol includes symbols mapped on the second constellation, and the transmission power of the second modulation symbol is redetermined according to the transmission power of the first modulation symbol, so that the probability of interception of information by the relay node can be reduced to a certain extent. Therefore, when the first modulation symbol and the second modulation symbol are received at the relay node, the information interception of the relay node can be prevented to a certain extent by the two modulation symbols, so that the probability of the information interception of the relay node is greatly reduced, and the information leakage is avoided. The generation method of the modulation symbol is not a theoretical modulation method, and the practicability of the signal design is realized.

The communication method provided in the embodiment of the present application will be described in detail below with reference to the accompanying drawings.

Fig. 4 is a schematic flow chart of a communication method suitable for use in embodiments of the present application. Fig. 4 shows a specific flow of the method from the point of view of interaction of the source node and the relay node. The relay node may correspond to the air mobile relay 105 in the V2V scenario shown in fig. 1, or may also correspond to the artificial earth satellite 203 in the satellite mobile communication scenario shown in fig. 2, or may also correspond to R in the scenario architecture shown in fig. 3. The first source node and the second source node may correspond to any two vehicles in the V2V scenario shown in fig. 1For example, the vehicle 101 may be used as a first source node, and the vehicle 104 may be used as a second source node, or may correspond to the earth station 201 and the earth station 202 in the satellite mobile communication scenario shown in fig. 2, for example, the earth station 201 may be used as a first source node, and the earth station 202 may be used as a second source node, or may also correspond to S in the scenario architecture shown in fig. 3 ₁ And S is ₂ For example S ₁ Can be used as a first source node and S ₂ Can act as a second source node.

The method 400 includes steps 410 through 440. The various steps in the method 400 shown in fig. 4 are described in detail below. Wherein steps 410 and 4301 describe actions performed by the first source node, steps 420 and 4302 describe actions performed by the second source node, and steps 430 and 440 describe actions performed by the relay node.

It should be understood that the first source node, the second source node, and the relay node are merely examples of execution bodies, and each step in the above method may be further performed by components (such as circuits, chips, chip systems, etc.) disposed in the first source node, the second source node, and the relay node, respectively, or may be further implemented by logic modules or software capable of implementing all or part of the functions of the first source node, the second source node, and the relay node. The embodiments of the present application are not limited in this regard.

In step 410, a first source node generates a first modulation symbol.

In order to avoid interception of information by the relay node when communication is performed between the first source node and the second source node, the first source node generates a first modulation symbol before sending a signal to the relay node.

The first modulation symbol is modulated based on a QAM modulation scheme. Specifically, the first modulation symbol may be modulated by a 16QAM scheme, modulated by a 64QAM scheme, or modulated by any other QAM scheme.

The first modulation symbol comprises symbols mapped on a first constellation diagram, a plurality of constellation points are arranged in the same quadrant in the first constellation diagram, the minimum distance between two adjacent constellation points in the same quadrant is smaller than 2k, and k is a constellation mapping normalization factor. Specifically, the minimum distance between two adjacent constellation points in the same quadrant is (2-2 c) k, and 0 < c < 1.

Wherein the constellation mapping normalization factor may be determined by: and after the energy sum of all constellation points in the constellation diagram is averaged, the energy sum is squared to obtain a waveform amplitude value, and the inverse of the waveform amplitude value is taken to obtain a constellation mapping normalization factor. For example, for a 16-point constellation, there are 4 constellation points with energy value of 2, 8 constellation points with energy value of 10, and 4 constellation points with energy value of 18, the sum of the capacities of all constellation points is 160, and the equal probability distribution of the 16 constellation points is 1/16, the average energy is 160+.16=10, and the waveform amplitude after the evolution is

Taking the reciprocal thereof, namely the constellation mapping normalization factor is +>

Wherein the energy of the constellation point may be determined by: the sum of the squares of the abscissa and the squares of the ordinate of the constellation points in the constellation.

In particular, the first modulation symbol is a symbol mapped on a first constellation, and the first constellation is in particular a constellation of how many points, depending on which QAM modulation scheme is adopted. For example, when the modulation scheme is a 16QAM modulation scheme, the first constellation is a 16-point constellation. For another example, when the modulation scheme is a 64QAM modulation scheme, the first constellation is a 64-point constellation. Accordingly, when the first constellation is a 16-point constellation, the number of constellation points in each quadrant is 4. And when the first constellation is a 64-point constellation, the number of constellation points in each quadrant is 16.

The eavesdropping degree of the relay node on the information can use the BER of the signal received by the relay node as an index, and the more the BER tends to be 0.5, the lower the risk of information leakage. It should be understood that BER refers to the proportion of the total number of bits transmitted to the number of bits in which an error occurs. For each bit, the value may be 0 or 1. The probability of each bit transmission being correct or incorrect is 1/2. Therefore, the more the BER of the signal received at the relay node approaches 0.5, the less likely the information is leaked.

In order to improve the bit error rate, the minimum distance between two adjacent constellation points in the same quadrant in the first constellation diagram is set to be smaller than 2k, namely the minimum distance is (2-2 c) k,0 < c < 1, and k is a constellation mapping normalization factor. Wherein the value of k depends on the first modulation symbol being determined according to the QAM modulation order, the value of k being different for different QAM modulation orders.

A 16QAM constellation is described below with reference to fig. 5.

Fig. 5 is a 16QAM constellation suitable for use in the embodiments provided herein. As shown in fig. 5, the I axis is the same-directional component axis, the Q axis is the orthogonal component axis, and there are four symbols in each quadrant, and each symbol may correspond to four bits. The coordinates of the four constellation points arranged along the I-axis direction from the negative half axis to the positive half axis are as follows: 3+c, -1-c, 1+c and 3-c. The coordinates of the four constellation points arranged along the Q-axis direction from the negative half axis to the positive half axis are also as follows: 3+c, -1-c, 1+c and 3-c. Substituting the constellation mapping normalization factor k, and in the same quadrant, the minimum distance between two adjacent constellation points along the I axis direction or the Q axis direction is (2-2 c) k. Because the value of c is more than 0 and less than 1, the minimum distance between two adjacent constellation points along the I axis direction or the Q axis direction in the same quadrant is more than 0 and less than 2 k.

In contrast, in the 16QAM constellation in the conventional manner, four constellation points arranged along the I/Q axis direction have coordinates sequentially from the negative half axis to the positive half axis on the I/Q axis: -3, -1, 1 and 3. It can be seen that the 16QAM constellation used in the present application introduces a parameter c, where the parameter c may pull up the distance between two adjacent constellation points in the same quadrant, and the distance between two adjacent constellation points may affect the symbol error rate (symbol error ratio, SER) of the signal received at the relay node, where the smaller the distance, the larger the probability of a symbol transmission error, the larger the SER, so that the probability of a bit transmission error is increased, thereby improving the BER of the signal received at the relay node, and reducing the risk of information interception.

It should be understood that, with different QAM modulation schemes, the number of constellation points on the QAM constellation is different, and the values of the coordinates from the negative half axis to the positive half axis of the constellation points arranged along the I/Q axis direction also change.

The specific position of the first modulation symbol on the QAM constellation can be obtained according to the following expression of the useful signal:

x _S1 ＝k×(m+j×n)

wherein x is _S1 For the useful signal to be transmitted by the first source node, m is the real part, corresponding to the I-axis in the QAM constellation, n is the imaginary part, corresponding to the Q-axis in the QAM constellation. When the 16QAM constellation diagram is adopted, the value of m is as follows: -3+c, -1-c, 1+c and 3-c, n being the value: -3+c, -1-c, 1+c and 3-c, 0 < c < 1.k is a constellation mapping normalization factor,

For example, when m is 3-c and n is also 3-c, the useful signal to be transmitted by the first source node, that is, the first modulation symbol generated is the symbol in the upper right corner of the 16QAM constellation in fig. 5.

It should be understood that, by adopting different QAM modulation schemes, the values of the parameters m and n are different, and the expression of the k parameter is also changed.

Further, the parameter c is determined by the parameter N, SNR and the amplitude ratio a.

Wherein the value of the parameter N is such that the difference between the target bit error rate and 0.5 is not greater than Q (N)/2, Q (N) is the right-tail function of the standard normal distribution, and Q (N)/2 is a monotonically decreasing function with respect to N. It should be appreciated that this target bit error rate is the desired bit error rate indicated in the foregoing summary.

Specifically, the target bit error rate is a desired bit error rate of the signal received at the relay node, which can be guaranteed to be 0 when the desired bit error rate takes a certain value.The difference of 5 is not more than 0.1, and the relay node can be considered to hardly eavesdrop on any information. While the difference between the desired bit error rate and 0.5 may be represented by Q (N)/2. That is, when Q (N)/2.ltoreq.0.1, that is Q (N). Ltoreq.0.2, almost no information is eavesdropped at the relay node. And Q (N) is the right-tail function of the normal distribution, the inverse function Q of reference Q (N) ^-1 As can be seen from the curve of (N), Q ^-1 (0.2) ≡ 0.8416, i.e., Q (0.8416) ≡0.2. That is, when the parameter N > 0.8416, it can be ensured that the difference between the target bit error rate and 0.5 is not more than 0.1, and the information is hardly intercepted at the relay node. It should be noted that, the right tail function of the standard normal distribution is the prior art, and will not be described here.

It will be appreciated that a person skilled in the art may choose a suitable value of N according to the actual requirements for anti-eavesdropping performance, as long as N > 0.8416 is guaranteed, and it is achieved that the bit error rate of the signal received at the relay node will tend to be as much as 0.5 as possible, i.e. the relay node will have almost no information to eavesdrop.

The SNR is the SNR of the first channel.

Specifically, the first channel is a channel between the first source node and the relay node, specifically, a channel in which the first source node points to the direction of the relay node. Since the first source node sends the first modulation symbol to the relay node in step 430 described below, the first channel is also referred to herein as the channel in the direction from the first source node to the relay node.

The SNR is calculated as follows:

SNR＝(P _S1 |h _S1R | ² )/σ ²

as previously described, P _S1 Signal transmission power for the first source node, h _S1R Sigma for the channel in the direction from the first source node to the relay node ² Is the noise power at the relay node.

And the amplitude ratio a is the ratio of the amplitude of the second channel to the second modulation symbol and the amplitude of the first channel to the first modulation symbol.

Specifically, the second channel is a channel between the second source node and the relay node. Since the second source node generates the second modulation symbol and transmits the second modulation symbol to the relay node in steps 420 and 430 described below, the second channel is also referred to herein as a channel in the direction from the second source node to the relay node.

The magnitude ratio a is calculated as follows:

as previously described, P _S1 And P _S2 Respectively the signal transmission power of the first source node and the signal transmission power of the second source node, h _S2R H is a channel from the second source node to the relay node _S1R Is the channel in the direction from the first source node to the relay node.

After the parameter N, SNR and the amplitude ratio a are determined in the manner described above, the parameter c can be further determined. In the present application, the determination of the parameter c is related to the modulation scheme of the first modulation symbol.

The method for determining the parameter c is described by taking the modulation scheme based on the first modulation symbol as an example, which is 16QAM, and the specific method for determining the parameter c is related to the SNR under different scenarios, and is described in detail below:

Case (1): in a scene with a small SNR, as in the V2V scene shown in fig. 1, the value of the SNR is generally small. Then, the parameter c can be determined by the following expression:

wherein,,

as can be seen from the foregoing description of the communication procedure in fig. 3, it is assumed that, after the second source node receives the signal forwarded by the relay node, the second modulation symbol in the received signal may be deleted by using the self-interference cancellation technique, so as to obtain the first modulation symbol sent by the first source node. At this time, althoughHowever, the second modulation symbol does not affect the receiving performance of the second source node because it is deleted, but the first modulation symbol affects the receiving performance of the second source node. In order to reduce the influence of the first modulation symbol on the receiving performance of the second source node, it is necessary to make the BER of the first modulation symbol obtained by the second source node as small as possible, i.e., as close to 0 as possible. Therefore, in order to minimize the BER of the first modulation symbol at the second source node and thereby ensure the receiving performance of the second source node, the present application introduces the parameter a ₀ The parameter a ₀ The optimal receiving performance of the second source node can be satisfied. From the above calculated parameter a ₀ As can be seen from the expression of a) ₀ The value of (2) is also affected by the parameter N. Thus, parameter a of the present application ₀ Is the point of optimal receiving performance of the second source node under the requirement of anti-eavesdropping performance.

It should be understood that a ₀ The value of (a) is not limited to the calculation, and may be directly assigned, for example, an empirical value may be obtained, and the value of (a) is satisfied ₀ The endowed value can meet the anti-eavesdrop performance requirement of the relay node and simultaneously ensure that the receiving performance of the second source node is excellent.

Case (2): in a scenario where the SNR is large, such as the satellite mobile communications scenario shown in fig. 2, the SNR is typically large. At this time, the liquid crystal display device,

and infinitely tends to 0. Then, the expression of the parameter c in (1) above can be theoretically simplified as:

then a ₀ The expression of (2) can also be simplified to

At this time, in a communication scene where SNR is large, a ₀ The value of 0.4472 is the second one to meet the requirement of anti-eavesdropping performanceThe source node receives the point of optimal performance.

In the process of

When approaching 0, i.e. assuming +.>

When the probability of error of bit transmission is approximately considered to be 0, the probability of error of bit transmission is just between transmission correctness and transmission error, namely, the probability of error of bit transmission is between transmission error and transmission correctness in a decision domain. In order to increase the probability of bit transmission errors, the transmission of bits needs to cross the decision domain and enter the transmission error result, so that the correction parameter epsilon is introduced, the expression of the corrected c can increase the probability of bit transmission errors, and the BER of the signal received by the relay node is increased. That is, in a scenario where SNR is large, the expression of c is:

/>

In the same way as described above,

it should be noted that, since the simplified expression of c no longer contains the parameter N, in order to ensure that the BER of the signal received at the relay node tends to be 0.5, epsilon may be 0.05.

It should be understood that, in either the case (1) or the case (2), different QAM modulation schemes are adopted, and the expression of the parameter c is also different, and thus the value of the parameter c finally calculated may also be different.

As can be seen from the foregoing description, the present application introduces the parameter c on the QAM constellation diagram to shorten the distance between two adjacent constellation points in the same quadrant, thereby helping to increase the bit error rate of the signal received at the relay node.

In order to further increase the bit error rate of the signal received at the relay node, the bit sequence corresponding to each constellation point in the first constellation is obtained based on non-gray code coding.

Specifically, each constellation point, i.e. each symbol, may correspondingly generate a preset number of bits, which are referred to as a bit sequence. In a conventional coding mode for bit sequences corresponding to constellation points, gray code coding is generally adopted, namely, only one bit has different values between two bit sequences corresponding to two adjacent constellation points, so that the bit transmission is not easy to make mistakes. In order to increase the bit error rate of the signal received at the relay node, the coding mode of the bit sequence corresponding to the constellation point adopts non-Gray code coding, namely, the values of at least two bits are different between two bit sequences corresponding to two adjacent constellation points. For example, for constellation points in 16QAM, in the same quadrant, two bits may have different values between two bit sequences corresponding to two adjacent constellation points. For constellation points in 64QAM, in the same quadrant, three bits can be different in value between two bit sequences corresponding to two adjacent constellation points. Compared with the conventional Gray code mapping, as the bit numbers with different bit values are improved, the probability of bit transmission errors is also improved, so that the bit error rate of signals received by the relay node is increased, and the interception of the signals by the relay node is further reduced. The gray code is a prior art code, and will not be described here.

The non-gray code encoding is described below in conjunction with fig. 6.

Fig. 6 is a 16QAM non-gray code encoded constellation suitable for use in embodiments of the present application. As shown in fig. 6, the I axis is the same directional component axis, the Q axis is the orthogonal component axis, and there are four symbols in each quadrant, and each symbol can correspondingly generate four bits. It can be seen that there is a difference in the values of two bits between two adjacent constellation points in the same quadrant. For example, in the quadrant in the upper right corner, the values of the first two bits are different between bit sequence 0110 and bit sequence 1010, and the values of the second two bits are different between bit sequence 0110 and bit sequence 0101. For another example, in the quadrant in the lower left corner, the values of the first two bits are different between bit sequence 0011 and bit sequence 1111, and the values of the second two bits are different between bit sequence 0011 and bit sequence 0000. Taking the bit sequence 0011 and the bit sequence 0000 as examples, when transmitting the bits, the probability of bit transmission errors is improved due to the difference of the last two bits between the two bit sequences, and accordingly, the BER of the signal received by the relay node is also improved, and the probability of eavesdropping information at the relay node is reduced.

In one possible implementation, the correspondence between the plurality of constellation points in the first constellation and the bit sequence is determined based on one of a predefined plurality of coding modes; the bit sequence comprises four bits, in each of the multiple coding modes, each constellation point corresponds to the first two bits of the bit sequence on the in-phase component I axis, and each constellation point corresponds to the second two bits of the bit sequence on the quadrature component Q axis; in any two coding modes of the multiple coding modes, the sequences of the bits corresponding to the constellation points on the I axis are different, and/or the sequences of the bits corresponding to the constellation points on the Q axis are different.

Specifically, take the example of the 16QAM non-gray code encoded constellation in fig. 6. It can be seen that the coordinates of each constellation point on the I-axis from the negative half axis to the positive half axis are respectively: (-3+c) k, (-1-c) k, (1+c) k and (3-c) k, the two bits corresponding to being in order: 00. 11, 01 and 10. The coordinates of each constellation point from the negative half axis to the positive half axis on the Q axis are respectively as follows: (-3+c) k, (-1-c) k, (1+c) k and (3-c) k, the two bits corresponding to are also in order: 00. 11, 01 and 10. Each constellation point corresponds to the first two bits of the bit sequence on the in-phase component I axis and each constellation point corresponds to the last two bits of the bit sequence on the quadrature component Q axis. For example, the bit sequence of the constellation point in the upper left corner is 0010, where the first two bits "00" correspond to coordinates "-3+c" on the I-axis and the second two bits "10" correspond to coordinates "3-c" on the Q-axis.

And the ordering of bits corresponding to coordinate points on the I-axis and the Q-axis is not limited to one shown in fig. 6. The present application defines a plurality of coding modes in advance, and the correspondence between a plurality of constellation points in the first constellation map and the bit sequence may be any one of the predefined plurality of coding modes. Taking fig. 6 as an example, bits "00" and "11" corresponding to the negative half axis of the constellation point on the I-axis are interchangeable, and bits "01" and "00" corresponding to the positive half axis are interchangeable, so that 4 coding modes can be predefined. The bits of the negative half axis and the positive half axis of the I-axis may also be interchanged, for example, the bit "00" corresponding to the negative half axis and the bit "10" corresponding to the positive half axis of the constellation point may be interchanged, and the bit "11" corresponding to the negative half axis and the bit "01" corresponding to the positive half axis may be interchanged, so that 4 encoding modes may be predefined. That is, 8 coding modes can be predefined for one side of the I-axis. Accordingly, there are 8 predefined coding modes for the Q-axis. Thus, for a 16QAM non-gray code encoded constellation, 64 (8×8) encoding modes can be predefined, and the correspondence between the plurality of constellation points in the 16QAM constellation and the bit sequences is determined by one of the predefined 64 encoding modes. Obviously, in any two-by-two coding mode, the orders of bit sequences corresponding to the coordinates of a plurality of constellation points on the I axis and/or the Q axis are also different.

It should be appreciated that with different QAM modulation schemes, the number of predefined coding schemes will also be different, e.g., for a 64QAM constellation, the number of predefined coding schemes will be greater.

Further, as can be seen from the foregoing description, the calculation of SNR and amplitude ratio a involves parameters such as channel amplitude, noise power, etc., and these parameters can be obtained by:

the first source node sends a first request to the relay node, the first request requesting first channel information. Accordingly, the relay node receives a first request from the first source node.

It should be understood that the manner in which the first source node obtains these parameters is not limited to the manner in which the first request is sent, and may also adopt a relay pre-configuration or a network configuration manner. The relay pre-configuration is that the relay node configures related parameters for the source node in advance, and the network configuration is that the content of the information parameters which are well transmitted in advance are uniformly decided in the wireless network. The specific manner in which the first source node obtains the above parameters is not limited in this application.

After receiving the first request, the relay node may send different first channel information to the first source node according to different conditions, and the following classification description is performed:

Case (1): in a scene where the SNR is small, as in the V2V scene shown in fig. 1,

the relay node transmits first channel information indicating the amplitude |h of the second channel _S2R I and noise power at relay node σ ² 。

Or, the first channel information is used for indicating the amplitude ratio of the second channel to the first channel _S2R /h _S1R I, and the ratio of the square of the first channel amplitude to the noise power at the relay node, h _S1R | ² /σ ² 。

Case (2): in a scenario where the SNR is large, as in the satellite mobile communications scenario shown in figure 2,

the relay node transmits first channel information indicating the amplitude |h of the second channel _S2R |。

Or, the first channel information is used for indicating the amplitude ratio of the second channel to the first channel _S2R /h _S1R |。

The foregoing is either case (1) or case (2), wherein the first channel is a channel between the first source node and the relay node, specifically a channel in a direction from the first source node to the relay node, and the second channel is a channel between the second source node and the relay node, specifically a channel in a direction from the second source node to the relay node.

Whether it is case (1) or case (2), the first source node receives the first channel information accordingly, so that the SNR and the amplitude ratio a can be determined from the parameters indicated by the first channel information.

It will be appreciated that the signal transmission power of the first source node and the signal transmission power of the second source node are known to the source node, since the source node itself is controlled by the source node itself when transmitting signals.

In one possible implementation, the first channel information may further include an ID of the second source node and a time stamp for indicating a time when the relay node acquired the parameter indicated in the first channel information. Specifically, the first source node may send the agreed pilot frequency to the relay node, and the relay node may obtain relevant parameters through channel estimation, so that the acquisition time of the parameters may also be obtained.

In one possible implementation, the first channel information is carried in a Sidelink (SL) message, a Uu port message, or uplink control information (uplink control information, UCI). The Uu port is a generic interface for implementing a User Equipment (UE) and an evolved universal terrestrial radio access network (evolved universal terrestrial radio access network, E-UTRAN).

It should be understood that if there is no base station in the first source node and the relay node, the first channel information is carried in the SL message, and if the first source node is a base station, the first channel information is carried in the Uu port message, or UCI.

In step 420, the second source node generates a second modulation symbol.

In order to avoid interception of information by the relay node when communication is performed between the first source node and the second source node, the second source node also generates a second modulation symbol before sending a signal to the relay node.

The second modulation symbol is modulated based on a QPSK modulation scheme or a BPSK modulation scheme.

The second modulation symbol comprises symbols mapped on a second constellation, wherein no more than one constellation point is in each quadrant in the second constellation, and the transmission power of the second modulation symbol is determined according to the transmission power of the first modulation symbol.

Wherein the transmit power of the second modulation symbol is determined according to the transmit power of the first modulation symbol, further comprising: the transmit power of the second modulation symbol is determined based on the predefined target amplitude ratio and the transmit power of the first modulation symbol. Wherein, the target amplitude ratio is takenA value of less than

At the same time, can approach a with larger value ₀ 。a ₀ Determined by the foregoing formula:

specifically, the second modulation symbol is a symbol mapped on the second constellation diagram, the adjustment manners based on the second modulation symbol are different, and the number of corresponding constellation points in the second constellation diagram is also different. For example, when the modulation scheme is a QPSK modulation scheme, the second constellation is a 4-point constellation. Fig. 7 is a QPSK constellation suitable for use in the embodiments of the present application. As shown in fig. 7, the I axis is the same-directional component axis, and the Q axis is the quadrature component axis, it can be seen that there are 1 symbol in each quadrant, whether the QPSK modulation of the present scheme or the QPSK modulation of the conventional scheme. For another example, when the modulation scheme is a BPSK modulation scheme, the second constellation is a 2-point constellation.

And the specific position of the second modulation symbol on the constellation diagram can be obtained according to the following expression of the useful signal:

wherein x is _S2 For the useful signal to be transmitted by the second source node, p is the real part, corresponding to the I-axis in the constellation diagram, Q is the imaginary part, corresponding to the Q-axis in the constellation diagram. When the QPSK constellation diagram is adopted, the values of p and q are respectively as follows: -1 or 1.

Wherein P is _S ′ ₂ For the transmission power of the second modulation symbol, θ _S2 Is the phase of the second modulation symbol.

It will be appreciated that the values of p and q will also change for different modulation schemes.

The transmission power P _S ′ ₂ Not the second source section indicated aboveDefault signal transmission power P known to the point itself _S2 The transmission power redetermined according to the predefined target amplitude ratio and the transmission power of the first modulation symbol can be determined specifically by the following manner:

the second source node determines the amplitude ratio a as follows:

as previously described, P _S1 Signal transmission power for the first source node, P _S2 Signal transmission power for the second source node, h _S2R H is a channel from the second source node to the relay node _S1R Is the channel in the direction from the first source node to the relay node. P is the same as _S1 And P _S2 Are all default, known signal transmit powers.

In order to ensure that the bit error rate of the signal received at the relay node tends to be 0.5, according to the above-mentioned step 410, the expression of the calculation parameter c can be found that only when the amplitude ratio a is smaller than the value

And the parameter c can be calculated, so that the anti-eavesdropping requirement at the relay node is met. And, in the above analysis, it is pointed out that parameter a ₀ Is the point of optimal receiving performance of the second source node under the requirement of meeting the anti-eavesdrop performance, so that the amplitude ratio a is more approximate to a ₀ The more the reception performance of the second source node can be ensured. And for the first source node, the larger the amplitude value of the amplitude value a is, the better the receiving performance of the first source node is. Namely, the value condition of the amplitude ratio a is: the amplitude ratio a takes on a value smaller than +.>

At the same time, can approach a with larger value ₀ . Therefore, the requirement of anti-eavesdropping performance at the relay node can be guaranteed, and the receiving performance of the source node can be guaranteed. For convenience of distinction and explanation, the above will be followedThe magnitude ratio determined by the value condition is noted as the target magnitude ratio a'.

Therefore, after the second source node determines the amplitude ratio a, the amplitude ratio a is assigned again according to the above-mentioned value condition, so as to obtain the target amplitude ratio a', and then the transmitting power P of the second modulation symbol is determined again _S ′ ₂ . The following are provided:

wherein a' is the target amplitude ratio, P _S ′ ₂ For the transmission power of the second modulation symbol, P _S1 The signal transmission power for the first source node, i.e. the transmission power of the first modulation symbol, is the default transmission power. h is a _S2R H is a channel from the second source node to the relay node _S1R Is the channel in the direction from the first source node to the relay node.

It can be seen that, because the target amplitude ratio a' can ensure the requirement of anti-eavesdropping performance at the relay node, the receiving performance of the source node can also be ensured. The re-determined transmission power P of the second modulation symbol _S ′ ₂ The method can ensure the anti-eavesdropping performance of the relay node and the receiving performance of the source node. That is, the second source node transmits power P by default to the signal _S2 Adjusting to retrieve the transmission power P _S ′ ₂ Therefore, the requirement of anti-eavesdropping performance at the relay node can be ensured, and the receiving performance of the source node can be ensured.

The phase theta of the second modulation symbol _S2 The phase difference Δθ is determined by the phase difference Δθ between the second channel and the first channel in the following manner:

Δθ＝angle(h _S2R /h _S1R )

wherein angle is the radian value used for solving the phase angle of the complex matrix, h _S2R H is a channel from the second source node to the relay node _S1R Is the channel in the direction from the first source node to the relay node.

Further, when the second modulation symbol is based on QPSK modulation, the phase θ of the second modulation symbol _S2 Phase difference from the phase difference delta theta

Is an integer multiple of (a).

l is an integer.

And when the second modulation symbol is based on BPSK modulation, the phase θ of the second modulation symbol _S2 Phase difference from the phase difference delta theta

Odd multiples of (2).

l is an integer.

Taking QPSK modulation in fig. 7 as an example, whether for the present scheme or the conventional scheme, the distance of the constellation point to the origin represents the transmit power of the signal, and the angle by which the constellation point is rotated represents the phase of the signal. It can be seen that under the conventional scheme, the transmitting power of the constellation point is

The transmission power of the second modulation symbol in this scheme is larger than that of the modulation symbols of the conventional scheme, i.e. the above-indicated +.>

And, the phase of the second modulation symbol in this scheme is also rotated further counterclockwise than the modulation symbol phase of the conventional scheme. That is, the second modulation symbol generated by the present application, whether phase or transmit power, is compared to The conventional scheme is improved. Moreover, based on the foregoing description, the re-determined transmitting power of the second modulation symbol in the scheme can ensure the requirement of anti-eavesdropping performance at the relay node, and also can ensure the receiving performance of the source node, and the re-determined phase can also reduce the eavesdropping probability of the relay node on the information. It should be understood that the conventional scheme in fig. 7, that is, the modulation symbol is obtained according to the QPSK modulation in the prior art, and the description of the QPSK modulation in the conventional scheme is not repeated herein.

Further, as can be seen from the foregoing description, the calculation of the amplitude ratio a involves parameters, such as channel amplitude, and the acquisition of these parameters can be obtained by:

the second source node sends a second request to the relay node, the second request requesting second channel information. Accordingly, the relay node receives a second request from a second source node.

Likewise, the manner in which the second source node obtains these parameters is not limited to the manner in which the second request is sent, and may also adopt a relay pre-configuration or a network configuration manner. The relay pre-configuration is that the relay node configures related parameters for the source node in advance, and the network configuration is that the content of the information parameters which are well transmitted in advance are uniformly decided in the wireless network. The manner in which the second source node obtains the above parameters is not limited in this application.

After receiving the second request, the relay node sends second channel information to the second source node, where the second channel information is used to indicate the amplitude |h of the first channel _S1R Phase angle of the first channel (h) _S1R ) The method comprises the steps of carrying out a first treatment on the surface of the Or, the amplitude ratio of the second channel to the first channel |h _S2R /h _S1R I and phase difference angle (h _S2R /h _S1R )；

The first channel is a channel between the first source node and the relay node, specifically a channel from the first source node to the relay node, and the second channel is a channel between the second source node and the relay node, specifically a channel from the second source node to the relay node.

Accordingly, the first source node receives the second channel information, so that the amplitude ratio a and the phase difference Δθ can be determined according to the parameters indicated by the second channel information.

In one possible implementation, the second channel information may further include an ID of the first source node and a time stamp for indicating a time when the relay node acquired the parameter indicated in the second channel information. Specifically, the second source node may send the agreed pilot frequency to the relay node, and the relay node may obtain relevant parameters through channel estimation, so that the acquisition time of the parameters may also be obtained.

In one possible implementation, the second channel information is carried in a side-uplink SL radio resource control RRC reconfiguration message, in a SL capability transfer message, in a SL medium access control MAC control element CE, or in a side-uplink control information SCI.

In step 430, the relay node receives a first signal.

In particular, the first signal comprises a first modulation symbol from a first source node and a second modulation symbol from a second source node. And after the relay node receives the first signal, step 430 includes step 4301, where the first source node sends a first modulation symbol to the relay node, and step 4302, where the second source node sends a second modulation symbol to the relay node, as corresponding to steps 410 and 420 above. In one possible design, a source node with a better channel link may be the first source node, the first modulation symbol may be generated in the manner of step 410, a source node with a worse channel link may be the second source node, and the second modulation symbol may be generated in the manner of step 420.

It should be understood that, based on the foregoing description of fig. 3, the first signal received by the relay node includes the first modulation symbol and the second modulation symbol, but the first modulation symbol and the second modulation symbol are obtained by the first source node and the second source node performing the above steps 410 and 420 to process the signal to be transmitted, and the relay node cannot parse the first modulation symbol and the second modulation symbol. In other words, the first signal received by the relay node is a mixed signal of the first modulation symbol and the second modulation symbol.

Specifically, the first modulation symbol is modulated based on a QAM modulation mode, and a parameter c is introduced into the QAM constellation diagram, and the parameter c draws the distance between two adjacent constellation points in the same quadrant, so that the symbol error rate of the signal received at the relay node is increased, and the bit error rate is indirectly increased, so that the bit error rate of the signal received at the relay node is increased. The determination of the parameter c is in turn related to the parameter N, which enables the bit error rate of the signal received at the relay node to be as close to 0.5 as possible, i.e. the introduction of the parameter c ensures that almost no information is eavesdropped at the relay node. And the bit sequence corresponding to the constellation point in the QAM constellation diagram is also obtained based on the non-Gray code, so that the bit error rate at the relay node is further improved. The transmitting power of the second modulation symbol is redetermined according to the predefined target amplitude ratio and the transmitting power of the first modulation symbol, the predefined target amplitude ratio can ensure the requirement of anti-eavesdropping performance at the relay node, and the redetermined phase of the second modulation symbol can further reduce the probability of information eavesdropping of the relay node. Thus, when the first modulation symbol and the second modulation symbol act on the relay node at the same time, the relay node hardly eavesdrops on any information. And the first source node adopts a first constellation diagram to map the first modulation symbol, the second source node adopts a second constellation diagram to map the second modulation symbol, and the amplitudes of all symbols in the second constellation diagram are consistent, so that after the first modulation symbol and the second modulation symbol are overlapped at the relay node, the interference amplitude of the second modulation symbol on the first modulation symbol is consistent, and the consistent eavesdropping prevention effect can be achieved.

The BER simulation results under different scenarios are described below in conjunction with fig. 8 to 11:

case (1): in a scene where the SNR is small, a V2V scene as shown in fig. 1.

Fig. 8 is a simulation diagram suitable for providing BER at a relay node in a V2V scenario in an embodiment of the present application. As shown in fig. 8, the curve a represents the simulation curve of the present scheme, the curve B represents the simulation curve of the gaussian scheme, rber1_s1 represents the BER of the first bit and the third bit at the relay node corresponding to the first modulation symbol transmitted by the first source node, rber2_s1 represents the BER of the second bit and the fourth bit at the relay node corresponding to the first modulation symbol transmitted by the first source node, and rber_s2 represents the BER of the second modulation symbol transmitted by the second source node at the relay node.

As can be seen from fig. 8, in the case of the parameter n=2.5, snr=25 dB, when the amplitude ratio a is in the range of 0.35 to 0.6, for the curve a of the present scheme, whether the rber1_s1 curve, the rber2_s1 curve, or the rber_s2 curve substantially coincides, and the BER at the relay node approaches substantially 0.5, interception of the signal by the relay node can be substantially completely avoided. And for the curve B of the Gaussian scheme, whether the curve B is the RBER1_S1 curve, the RBER2_S1 curve or the RBER_S2 curve, the BER of the curve B at the relay node is greatly smaller than 0.5 but larger than 0.1, and the interception of signals by the relay node can be avoided only by a small amount. Thus, the solution of the present application is significantly better than the gaussian solution adopted by the prior art. When the scheme is adopted, when the value of a is in the range of 0.35-0.6, the interception of the relay node to the signal can be basically completely avoided.

Fig. 9 is a simulation diagram suitable for providing BER at a source node in a V2V scenario in accordance with an embodiment of the present application. As shown in fig. 9, the curve a represents the simulation curve of the present scheme, the curve B represents the simulation curve of the gaussian scheme, the BER 1S 2 represents the BER of the first bit and the third bit at the second source node corresponding to the first modulation symbol transmitted by the first source node, the BER 2S 2 represents the BER of the second bit and the fourth bit at the second source node corresponding to the first modulation symbol transmitted by the first source node, and the ber_s1 represents the BER of the second modulation symbol transmitted by the second source node at the first source node.

As can be seen from fig. 9, in the case of the parameter n=2.5 and snr=25 dB, similarly, when the amplitude ratio a is in the range of 0.35 to 0.6, the curve a of the present scheme and the curve B of the gaussian scheme substantially coincide, and the BER at the source node approaches substantially 0 in this range, regardless of whether the curve is the curve BER1_s2, the curve BER2_s2, or the curve ber_s1. Therefore, when the value of a is in the range of 0.35-0.6, the scheme can also well ensure the receiving performance of the source node.

Case (2): in a scenario where SNR is large, a satellite mobile communication scenario is illustrated in fig. 2.

Fig. 10 is a simulation diagram of BER at a relay node in a scenario for providing satellite mobile communications according to an embodiment of the present application. As shown in fig. 10, similarly, the a curve represents the simulation curve of the present scheme, the B curve represents the simulation curve of the gaussian scheme, rber1_s1 represents the BER of the first bit and the third bit corresponding to the first modulation symbol transmitted by the first source node at the relay node, rber2_s1 represents the BER of the second bit and the fourth bit corresponding to the first modulation symbol transmitted by the first source node at the relay node, and rber_s2 represents the BER of the second modulation symbol transmitted by the second source node at the relay node.

As can be seen from fig. 10, in the case of the compensation parameter epsilon=0.05 and snr=50 dB, when the amplitude ratio a is in the range of 0.05 to 0.95, the curves a for this scheme, whether the rber1_s1 curve, the rber2_s1 curve, or the rber_s2 curve, are substantially coincident, and the BER at the relay node is substantially approaching 0.5, eavesdropping of the signal by the relay node can be substantially completely avoided. And for the curve B of the Gaussian scheme, whether the curve B is the RBER1_S1 curve, the RBER2_S1 curve or the RBER_S2 curve, the BER of the curve B at the relay node is greatly smaller than 0.5 but larger than 0.1, and the interception of signals by the relay node can be avoided only by a small amount. Therefore, the scheme of the application is obviously superior to the Gaussian scheme adopted by the prior art, and when the scheme of the application is adopted, when the value of a is in the range of 0.05-0.95, the interception of signals by the relay node can be basically and completely avoided.

Fig. 11 is a simulation diagram of BER at a source node in a scenario for providing satellite mobile communications in accordance with an embodiment of the present application. As shown in fig. 11, similarly, the a curve represents the simulation curve of the present scheme, the B curve represents the simulation curve of the gaussian scheme, BER 1S 2 represents the BER of the first bit and the third bit at the second source node corresponding to the first modulation symbol transmitted by the first source node, BER 2S 2 represents the BER of the second bit and the fourth bit at the second source node corresponding to the first modulation symbol transmitted by the first source node, and ber_s1 represents the BER of the second modulation symbol transmitted by the second source node at the first source node.

As can be seen from fig. 11, in the case where the compensation parameter epsilon=0.05 and snr=50 dB, similarly, when the amplitude ratio a is in the range of 0.05 to 0.95, the curve a of the present scheme and the curve B of the gaussian scheme substantially coincide, and the BER at the source node substantially approaches 0 in the range, regardless of whether the curve is the curve BER1_s2, the curve BER2_s2, or the curve ber_s1. Therefore, when the value of a is in the range of 0.05-0.95, the receiving performance of the source node can be well ensured.

In step 440, the relay node forwards the first signal.

The description of step 440 may be understood with reference to the foregoing description of the second stage of the communication process of fig. 3, and will not be repeated here.

Based on the scheme, the first modulation symbol sent by the first source node to the relay node is modulated based on a QAM modulation mode, a parameter c is introduced into the QAM constellation diagram, and the distance between two adjacent constellation points in the same quadrant is shortened by using the parameter c, so that the minimum distance between the two adjacent constellation points in the same quadrant is smaller than 2k, and the bit error rate of a signal received by the relay node is increased to a certain extent. The determination of the parameter c is influenced by the parameter N, which is a parameter that enables the bit error rate of the signal received at the relay node to approach 0.5 as much as possible, so the parameter c is introduced in order to ensure that almost no information is eavesdropped at the relay node. And the bit sequence of the constellation points in the QAM constellation diagram is obtained based on non-Gray codes, so that the bit error rate at the relay node is further improved. The transmitting power of the second modulation symbol is redetermined according to the predefined target amplitude ratio and the transmitting power of the first modulation symbol, the predefined target amplitude ratio can ensure the requirement of anti-eavesdropping performance at the relay node, and the redetermined phase of the second modulation symbol can further reduce the probability of information eavesdropping of the relay node. Therefore, when the first modulation symbol and the second modulation symbol act on the relay node at the same time, the relay node can hardly eavesdrop any information from the received mixed signal, and the effect of completely avoiding the eavesdrop of the relay node on the information is achieved. In addition, the scheme for designing the signal for the source node is completely realized, and the practicability of the signal design is realized.

The method provided in the embodiment of the present application is described in detail above with reference to fig. 4 to 11. The following describes in detail the apparatus provided in the embodiments of the present application with reference to fig. 12 to 14.

Fig. 12 is a schematic block diagram of a communication device provided in an embodiment of the present application. The communication apparatus 1200 may correspond to a relay node in a method embodiment, for example, the communication apparatus 1200 may be a relay node, a component (such as a circuit, a chip, a system on a chip, etc.) in a relay node, or a logic module or software capable of implementing all or part of the functions of the relay node. The relay node may be, for example, the airborne mobile relay 105 in fig. 1, or the satellite 203 in fig. 2. The embodiments of the present application are not limited in this regard.

As shown in fig. 12, the communication apparatus 1200 may include: a receiving unit 1210 and a processing unit 1220. The units in the apparatus 1200 may be used to implement the corresponding flow performed by the relay node in the method 400 shown in fig. 4. For example, the receiving unit 1210 may be used for performing step 430 in the method 400, and the processing unit 1220 may be used for performing step 440 in the method 400.

In particular, the receiving unit 1210 may be configured to receive a first signal, where the first signal includes a first modulation symbol from a first source node and a second modulation symbol from a second source node; the first modulation symbol comprises symbols mapped on a first constellation diagram, the number of constellation points in the same quadrant in the first constellation diagram is multiple, the minimum distance between two adjacent constellation points in the same quadrant is smaller than 2k, and k is a constellation mapping normalization factor; the second modulation symbol comprises symbols mapped on a second constellation, wherein no more than one constellation point is in each quadrant in the second constellation, and the transmission power of the second modulation symbol is determined according to the transmission power of the first modulation symbol. The processing unit 1220 may be configured to forward the first signal.

Optionally, the processing unit 1220 may be further configured to send first channel information to the first source node, where the first channel information is used to indicate an amplitude of the second channel and a noise power at the relay node; or, the first channel information is used to indicate the amplitude ratio of the second channel to the first channel, and the ratio of the square of the amplitude of the first channel to the noise power at the relay node; the first channel is a channel between the first source node and the relay node, and the second channel is a channel between the second source node and the relay node.

Optionally, the receiving unit 1210 may be further configured to receive a first request from a first source node, where the first request is used to request first channel information.

Optionally, the processing unit 1220 may be further configured to send second channel information to the second source node, where the second channel information is used to indicate the amplitude of the first channel and the phase of the first channel; or, the amplitude ratio and the phase difference of the second channel and the first channel; the first channel is a channel between the first source node and the relay node, and the second channel is a channel between the second source node and the relay node.

Optionally, the receiving unit 1210 may be further configured to receive a second request from a second source node, where the second request is used to request second channel information.

Optionally, the minimum distance between two adjacent constellation points in the same quadrant is (2-2 c) k,0 < c < 1.

Optionally, the parameter c is determined by the parameter N, SNR and the amplitude ratio a; wherein the value of the parameter N makes the difference between the target bit error rate and 0.5 not larger than Q (N)/2, and Q (N) is a right tail function of standard normal distribution; the SNR is the SNR of the first channel, and the amplitude ratio a is the ratio of the amplitude of the second channel to the amplitude of the second modulation symbol and the amplitude of the first channel to the amplitude of the first modulation symbol.

Optionally, the determining manner of the parameter c is related to the modulation manner of the first modulation symbol.

Optionally, the bit sequence corresponding to each constellation point in the first constellation map is obtained based on non-gray code encoding.

Optionally, the correspondence between the plurality of constellation points in the first constellation and the bit sequence is determined based on one of a predefined plurality of coding modes; the bit sequence comprises four bits, in each of the multiple coding modes, each constellation point corresponds to the first two bits of the bit sequence on the in-phase component I axis, and each constellation point corresponds to the second two bits of the bit sequence on the quadrature component Q axis; in any two coding modes of the multiple coding modes, the sequences of the bits corresponding to the constellation points on the I axis are different, and/or the sequences of the bits corresponding to the constellation points on the Q axis are different.

Optionally, the first modulation symbol is modulated based on a quadrature amplitude modulation scheme.

Optionally, the second modulation symbol is modulated based on a quadrature phase shift keying modulation scheme or a binary phase shift keying modulation scheme.

Optionally, the phase of the second modulation symbol is determined by a phase difference between a second channel and a first channel, the first channel is a channel between the first source node and the relay node, and the second channel is a channel between the second source node and the relay node.

Is an integer multiple of (a).

Odd multiples of (2).

It should be understood that the division of the units in the embodiments of the present application is illustrative, and is merely a logic function division, and there may be another division manner in actual implementation. In addition, each functional unit in the embodiments of the present application may be integrated in one processor, or may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

Fig. 13 is another schematic block diagram of a communication device provided by an embodiment of the present application. The communications apparatus 1300 can correspond to a first source node or a second source node in a method embodiment, for example, the communications apparatus 1300 can be the first source node or the second source node, a component (such as a circuit, a chip, a system on a chip, etc.) in the first source node or the second source node, or a logic module or software capable of implementing all or part of the functions of the first source node or the second source node. The first source node may be, for example, any of the vehicles in fig. 1, such as vehicle 101, or any of the earth stations in fig. 2, such as earth station 201. The second source node may be any of the other vehicles of fig. 1 other than the vehicle that is the first source node, such as vehicle 104, or earth station 202 of fig. 2. The embodiments of the present application are not limited in this regard.

As shown in fig. 13, the communication apparatus 1300 may include: a generating unit 1310 and a transceiving unit 1320.

In one possible design, the elements in apparatus 1300 may be used to implement the corresponding flow performed by the first source node in method 400 shown in fig. 4. For example, the generating unit 1310 may be used to perform step 410 in the method 400, and the transceiving unit 1320 may be used to perform step 4301 and step 440 in the method 400.

For example, when the apparatus 1300 is used for implementing the function of the first source node in the method provided by the embodiment of the present application, the generating unit 1310 may be configured to generate a first modulation symbol, where the first modulation symbol includes a symbol mapped on a first constellation, the number of constellation points in the same quadrant in the first constellation is multiple, and a minimum distance between two adjacent constellation points in the same quadrant is less than 2k, where k is a constellation mapping normalization factor. The transceiving unit 1320 may be configured to send the first modulation symbol to a relay node.

Optionally, the transceiver unit 1320 is further configured to receive first channel information, where the first channel information is used to indicate an amplitude of the second channel and a noise power at the relay node; or, the first channel information is used to indicate the amplitude ratio of the second channel to the first channel, and the ratio of the square of the amplitude of the first channel to the noise power at the relay node; the first channel is a channel between the first source node and the relay node, and the second channel is a channel between the second source node and the relay node.

Optionally, the transceiving unit 1320 is further configured to send a first request to the relay node, the first request being for requesting the first channel information.

Optionally, parameter c is determined by parameter N, SNR and amplitude ratio a; wherein the value of the parameter N makes the difference between the target bit error rate and 0.5 not larger than Q (N)/2, and Q (N) is a right tail function of standard normal distribution; the SNR is the SNR of the first channel and the amplitude ratio a is the ratio of the amplitude of the second channel to the amplitude of the second modulation symbol and the amplitude of the first channel to the amplitude of the first modulation symbol.

Optionally, the correspondence between the plurality of constellation points in the first constellation and the bit sequence is determined based on one of a predefined plurality of coding modes; the bit sequence comprises four bits, in each of a plurality of coding modes, each constellation point corresponds to the first two bits of the bit sequence on an in-phase component I axis, and each constellation point corresponds to the second two bits of the bit sequence on a quadrature component Q axis; in any two coding modes of the multiple coding modes, the sequences of the bits corresponding to the constellation points on the I axis are different, and/or the sequences of the bits corresponding to the constellation points on the Q axis are different.

In another possible design, the elements in the apparatus 1300 may be used to implement the corresponding flow performed by the second source node in the method 400 shown in fig. 4. For example, the generating unit 1310 may be used to perform step 420 in the method 400, and the transceiving unit 1320 may be used to perform step 4302 and step 440 in the method 400.

Illustratively, when the apparatus 1300 is configured to implement the function of the second source node in the method provided by the embodiments of the present application, the generating unit 1310 may be configured to generate a second modulation symbol, where the second modulation symbol includes symbols mapped on a second constellation, where there is no more than one constellation point in each quadrant in the second constellation, and the transmit power of the second modulation symbol is determined according to the transmit power of the first modulation symbol. The transceiving unit 1320 may be configured to transmit the second modulation symbol to the relay node.

Optionally, the transceiver unit 1320 may be further configured to receive second channel information, where the second channel information is used to indicate an amplitude of the first channel and a phase of the first channel; or, the amplitude ratio and the phase difference of the second channel and the first channel; the first channel is a channel between the first source node and the relay node, and the second channel is a channel between the second source node and the relay node.

Optionally, the transceiver unit 1320 may be further configured to send a second request to the relay node, where the second request is used to request the second channel information.

Optionally, the second modulation symbol is based on quadrature phase shift keying modulation mode, and the phase θ of the second modulation symbol _S2 And the phase difference delta theta by an integer multiple of pi/2.

Optionally, the second modulation symbol is based onBinary phase shift keying modulation mode, phase theta of second modulation symbol _S2 And a phase difference delta theta by an odd multiple of pi/4.

Fig. 14 is another schematic block diagram of a communication device provided by an embodiment of the present application. The communication device 1400 may be a system-on-a-chip. In the embodiment of the application, the chip system may be formed by a chip, and may also include a chip and other discrete devices.

As shown in fig. 14, the apparatus 1400 may include at least one processor 1410.

In one possible design, at least one processor 1410 may be used to implement the functions of a relay node in the methods provided by embodiments of the present application.

Illustratively, when the apparatus 1400 is configured to implement the functionality of a relay node in the methods provided by embodiments of the present application, the processor 1410 may be configured to receive a first signal that includes a first modulation symbol from a first source node and a second modulation symbol from a second source node; the first modulation symbol comprises symbols mapped on a first constellation diagram, the number of constellation points in the same quadrant in the first constellation diagram is multiple, the minimum distance between two adjacent constellation points in the same quadrant is smaller than 2k, and k is a constellation mapping normalization factor; the second modulation symbol comprises symbols mapped on a second constellation, wherein no more than one constellation point is arranged in each quadrant in the second constellation, and the transmitting power of the second modulation symbol is determined according to the transmitting power of the first modulation symbol; the first signal is forwarded. Reference is made specifically to the detailed description in the method examples, and details are not described here.

In another possible design, at least one processor 1410 may be used to implement the functions of the first source node or the second source node in the method provided in the embodiments of the present application.

Illustratively, when the apparatus 1400 is configured to implement the function of the first source node or the second source node in the method provided by the embodiments of the present application, the processor 1410 may be configured to generate a first modulation symbol, where the first modulation symbol includes a symbol mapped on a first constellation, the number of constellation points in the same quadrant in the first constellation is multiple, and a minimum distance between two adjacent constellation points in the same quadrant is less than 2k, where k is a constellation mapping normalization factor; transmitting the first modulation symbol to a relay node; alternatively, the method may include generating a second modulation symbol, the second modulation symbol including symbols mapped on a second constellation, the second constellation having no more than one constellation point within each quadrant, the transmit power of the second modulation symbol being determined from the transmit power of the first modulation symbol; the second modulation symbol is transmitted to the relay node. Reference is made specifically to the detailed description in the method examples, and details are not described here.

The apparatus 1400 may also include at least one memory 1420 to store program instructions and/or data. Memory 1420 is coupled to processor 1410. The coupling in the embodiments of the present application is an indirect coupling or communication connection between devices, units, or modules, which may be in electrical, mechanical, or other forms for information interaction between the devices, units, or modules. The processor 1410 may operate in conjunction with the memory 1420. Processor 1410 may execute program instructions stored in memory 1420. At least one of the at least one memory may be included in the processor.

The apparatus 1400 may also include a communication interface 1430 for communicating with other devices over a transmission medium so that the apparatus 1400 may communicate with other devices. Illustratively, when the apparatus 1400 is configured to implement the function of the relay node in the method provided in the embodiment of the present application, the other device may be a first source node or a second source node; the apparatus 1400 may be configured to implement the function of the first source node or the second source node in the method provided by the embodiment of the present application, where the other device may be a relay node. The communication interface 1430 may be, for example, a transceiver, an interface, a bus, circuitry, or a device capable of implementing a transceiver function. The processor 1410 may utilize the communication interface 1430 to receive and transmit data and/or information and may be used to implement methods performed by the relay node, the first source node, or the second source node in the corresponding embodiment of fig. 4.

The specific connection medium between the processor 1410, the memory 1420, and the communication interface 1430 is not limited in the embodiments of the application. The present embodiment is illustrated in fig. 14 as being coupled between processor 1410, memory 1420, and communication interface 1430 via bus 1440. The bus 1440 is shown in bold lines in fig. 14, and the manner in which the other components are connected is merely illustrative and not limiting. The bus may be classified as an address bus, a data bus, a control bus, etc. For ease of illustration, only one thick line is shown in fig. 14, but not only one bus or one type of bus.

It should be appreciated that the processor in this application may be an integrated circuit chip with signal processing capabilities. In implementation, the steps of the above method embodiments may be implemented by integrated logic circuits of hardware in a processor or instructions in software form. The processor may be a general purpose processor, a digital signal processor (digital signal processor, DSP), an application specific integrated circuit (application specific integrated circuit, ASIC), a field programmable gate array (field programmable gate array, FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware components. The disclosed methods, steps, and logic blocks in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present application may be embodied directly in hardware, in a decoded processor, or in a combination of hardware and software modules in a decoded processor. The software modules may be located in a random access memory, flash memory, read only memory, programmable read only memory, or electrically erasable programmable memory, registers, etc. as well known in the art. The storage medium is located in a memory, and the processor reads the information in the memory and, in combination with its hardware, performs the steps of the above method.

It should also be appreciated that the memory in embodiments of the present application may be either volatile memory or nonvolatile memory, or may include both volatile and nonvolatile memory. The nonvolatile memory may be a read-only memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an electrically Erasable EPROM (EEPROM), or a flash memory. The volatile memory may be random access memory (random access memory, RAM) which acts as an external cache. By way of example, and not limitation, many forms of RAM are available, such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous DRAM (SLDRAM), and direct memory bus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to comprise, without being limited to, these and any other suitable types of memory.

The present application also provides a computer program product comprising: a computer program (which may also be referred to as code, or instructions), when executed, causes a computer to perform the method performed by the first source node, the method performed by the second source node, or the method performed by the relay node in the embodiment shown in fig. 4.

The present application also provides a computer-readable storage medium storing a computer program (which may also be referred to as code, or instructions). The computer program, when executed, causes the computer to perform the method performed by the first source node, the method performed by the second source node, or the method performed by the relay node in the embodiment shown in fig. 4.

The terms "unit," "module," and the like as used in this specification may be used to refer to a computer-related entity, either hardware, firmware, a combination of hardware and software, or software in execution.

Those of ordinary skill in the art will appreciate that the various illustrative logical blocks (illustrative logical block) and steps (steps) described in connection with the embodiments disclosed herein can be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application. In the several embodiments provided in this application, it should be understood that the disclosed apparatus, device, and method may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit.

In the above-described embodiments, the functions of the respective functional units may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions (programs). When the computer program instructions (program) are loaded and executed on a computer, the processes or functions according to the embodiments of the present application are fully or partially produced. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by a wired (e.g., coaxial cable, fiber optic, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a digital video disc (digital video disc, DVD)), or a semiconductor medium (e.g., a Solid State Disk (SSD)), or the like.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of the embodiments of the present application. And the aforementioned storage medium includes: a usb disk, a removable hard disk, a ROM, a RAM, a magnetic disk, or an optical disk, etc.

The foregoing is merely specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes or substitutions are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method of communication, comprising:

the relay node receives a first signal, wherein the first signal comprises a first modulation symbol from a first source node and a second modulation symbol from a second source node; the first modulation symbol comprises symbols mapped on a first constellation diagram, the number of constellation points in the same quadrant in the first constellation diagram is multiple, the minimum distance between two adjacent constellation points in the same quadrant is smaller than 2k, and k is a constellation mapping normalization factor; the second modulation symbols comprise symbols mapped on a second constellation diagram, wherein no more than one constellation point is arranged in each quadrant in the second constellation diagram, and the transmitting power of the second modulation symbols is determined according to the transmitting power of the first modulation symbols;

the relay node forwards the first signal.

2. The method of claim 1, wherein the method further comprises:

the relay node sends first channel information to the first source node, wherein the first channel information is used for indicating the amplitude value of a second channel and the noise power of the relay node; or, the first channel information is used for indicating the amplitude ratio of the second channel to the first channel and the ratio of the square of the amplitude of the first channel to the noise power at the relay node;

The first channel is a channel between the first source node and the relay node, and the second channel is a channel between the second source node and the relay node.

3. The method of claim 2, wherein the method further comprises:

the relay node receives a first request from the first source node, the first request requesting the first channel information.

4. A method according to any one of claims 1 to 3, wherein the method further comprises:

the relay node sends second channel information to the second source node, wherein the second channel information is used for indicating the amplitude value of a first channel and the phase of the first channel; or, the amplitude ratio and the phase difference of the second channel and the first channel;

5. The method of claim 4, wherein the method further comprises:

the relay node receives a second request from the second source node, the second request being for requesting the second channel information.

6. A method of communication, comprising:

the method comprises the steps that a first source node generates a first modulation symbol, wherein the first modulation symbol comprises symbols mapped on a first constellation diagram, a plurality of constellation points are arranged in the same quadrant in the first constellation diagram, the minimum distance between two adjacent constellation points in the same quadrant is smaller than 2k, and k is a constellation mapping normalization factor;

the first source node sends the first modulation symbol to a relay node.

7. The method of claim 6, wherein the method further comprises:

the first source node receives first channel information, wherein the first channel information is used for indicating the amplitude value of a second channel and the noise power of the relay node; or, the first channel information is used for indicating the amplitude ratio of the second channel to the first channel and the ratio of the square of the amplitude of the first channel to the noise power at the relay node;

8. The method of claim 7, wherein the method further comprises:

The first source node sends a first request to a relay node, wherein the first request is used for requesting the first channel information.

9. A method of communication, comprising:

the second source node generates a second modulation symbol, wherein the second modulation symbol comprises symbols mapped on a second constellation diagram, no more than one constellation point in each quadrant in the second constellation diagram, and the transmitting power of the second modulation symbol is determined according to the transmitting power of the first modulation symbol;

the second source node sends the second modulation symbol to a relay node.

10. The method of claim 9, wherein the method further comprises:

the second source node receives second channel information, wherein the second channel information is used for indicating the amplitude value of a first channel and the phase of the first channel; or, the amplitude ratio and the phase difference of the second channel and the first channel;

the first channel is a channel between a first source node and the relay node, and the second channel is a channel between the second source node and the relay node.

11. The method of claim 10, wherein the method further comprises:

the second source node sends a second request to the relay node, wherein the second request is used for requesting the second channel information.

12. A method according to any one of claims 1 to 11, wherein the minimum distance between two adjacent constellation points in the same quadrant is (2-2 c) k,0 < c < 1.

13. The method of claim 12, wherein the parameter c is determined by the parameter N, the signal-to-noise ratio SNR, and the amplitude ratio a; wherein the value of the parameter N ensures that the difference value between the target bit error rate and 0.5 is not more than Q (N)/2, and Q (N) is a right tail function of standard normal distribution; the SNR is the SNR of a first channel, and the amplitude ratio a is the ratio of the amplitude of a second channel to the amplitude of the second modulation symbol and the amplitude of the first channel to the amplitude of the first modulation symbol.

14. A method according to claim 12 or 13, characterized in that the manner of determining the parameter c is related to the modulation manner of the first modulation symbol.

15. A method according to any one of claims 1 to 14, wherein the bit sequence corresponding to each constellation point in the first constellation is derived based on non-gray code encoding.

16. The method of claim 15, wherein correspondence of a plurality of constellation points in the first constellation to a bit sequence is determined based on one of a predefined plurality of coding modes;

The bit sequence comprises four bits, in each of the multiple coding modes, each constellation point corresponds to the first two bits of the bit sequence on the in-phase component I axis, and each constellation point corresponds to the second two bits of the bit sequence on the quadrature component Q axis;

in any two coding modes of the multiple coding modes, the corresponding bit sequences of the constellation points on the I axis are different, and/or the corresponding bit sequences of the constellation points on the Q axis are different.

17. The method according to any one of claims 1 to 16, wherein the first modulation symbol is modulated based on a quadrature amplitude modulation scheme.

18. The method according to any one of claims 1 to 5, 9 to 11, wherein the second modulation symbol is modulated based on a quadrature phase shift keying modulation scheme or a binary phase shift keying modulation scheme.

19. The method of any of claims 1-5, 9-11, 18, wherein a phase of the second modulation symbol is determined by a phase difference of a second channel and a first channel, the first channel being a channel between the first source node and the relay node, the second channel being a channel between the second source node and the relay node.

20. The method of claim 19, wherein the second modulation symbol is based on a quadrature phase shift keying modulation scheme, a phase θ of the second modulation symbol _S2 Phase difference from the phase difference delta theta

Integer multiples of (2); or alternatively, the first and second heat exchangers may be,

the second modulation symbol is based on a binary phase shift keying modulation mode, and the phase theta of the second modulation symbol _S2 Phase difference from the phase difference

Odd multiples of (2).

21. A communication device comprising means for performing the method of any of claims 1 to 20.

22. A communication device comprising a processor for executing program code for implementing the method of any of claims 1 to 20.

23. A computer readable storage medium having stored thereon a computer program, which when executed by a processor causes a computer to perform the method of any of claims 1 to 20.

24. A computer program product comprising a computer program which, when run, causes a computer to perform the method of any one of claims 1 to 20.