Communication methods and communication devices

Abstract

A communication method and a communication apparatus are provided. The method includes: a relay node receiving a first signal, the first signal including a first modulation symbol from a first source node and a second modulation symbol from a second source node, wherein the first modulation symbol includes a symbol mapped on a first constellation diagram, the first constellation diagram having multiple constellation points in the same quadrant, and the minimum distance between two adjacent constellation points in the same quadrant being less than 2k, where k is a constellation mapping normalization factor; the second modulation symbol includes a symbol mapped on a second constellation diagram, the second constellation diagram having no more than one constellation point in each quadrant, and the transmission power of the second modulation symbol being determined based on the transmission power of the first modulation symbol; the relay node then forwards the first signal. By reducing the distance between adjacent constellation points in the same quadrant and re-determining the transmission power, the bit error rate of the first signal received by the relay node is improved, thereby greatly reducing the risk of the relay node eavesdropping on information.

Description

Technical Field

[0001] This application relates to the field of communications, and more specifically, to communication methods and communication apparatus. Background Technology

[0002] With the development of communication technology, bidirectional relay systems, which use two source nodes to exchange information via a relay node, are being increasingly studied due to their ability to save information transmission time slots and improve communication transmission rates. However, during communication between source nodes, the relay node may eavesdrop on the transmitted information, leading to information leakage. Therefore, secure communication in bidirectional relay systems has become a new concern.

[0003] Currently, precoding and cooperative jamming techniques are commonly used to design signals transmitted by source nodes to improve secure transmission rates during communication. However, this approach generally assumes the signal is Gaussian, which is difficult to implement practically in real-world communication. Even in studies that consider specific modulation methods, the phase and power of commonly used modulation signals are designed based on channel state information, resulting in signal superposition at the relay node. This provides a small probability of preventing relay eavesdropping, but the risk of information leakage still exists. Therefore, how to achieve practical signal design to significantly reduce information leakage has become a pressing technical problem. Summary of the Invention

[0004] This application provides a communication method and a communication device in order to minimize information leakage through a practical signal design.

[0005] In a first aspect, this application provides a communication method that can be executed by a relay node, or by a component (such as a chip, chip system, etc.) configured in the relay node, or by a logic module or software capable of implementing all or part of the relay node's functions. This application does not limit the scope of the method.

[0006] For example, the method includes: a relay node receiving a first signal, the first signal including a first modulation symbol from a first source node and a second modulation symbol from a second source node; wherein the first modulation symbol includes a symbol mapped on a first constellation diagram, the first constellation diagram having multiple constellation points in the same quadrant, and the minimum distance between two adjacent constellation points in the same quadrant being less than 2k, where k is a constellation mapping normalization factor; the second modulation symbol includes a symbol mapped on a second constellation diagram, the second constellation diagram having no more than one constellation point in each quadrant, and the transmission power of the second modulation symbol being determined based on the transmission power of the first modulation symbol; and the relay node forwarding the first signal.

[0007] The constellation mapping normalization factor can be determined as follows: The average of the sum of the energies of all constellation points in the constellation diagram is taken, and the square root is used to obtain the waveform amplitude value. The reciprocal of this waveform amplitude value yields the constellation mapping normalization factor. The energy of a constellation point can be determined as the sum of the squares of the x-coordinate and y-coordinate of the constellation point in the constellation diagram.

[0008] The transmission power of the second modulation symbol is determined based on the transmission power of the first modulation symbol, further including: the transmission power of the second modulation symbol is determined based on a predefined target amplitude ratio and the transmission power of the first modulation symbol. The target amplitude ratio is less than... At the same time, it can approach a0 with a relatively large value. a0 is determined by the following formula:

[0009]

[0010] Where a0 is the point that satisfies the optimal receiving performance of the second source node, SNR is the signal-to-noise ratio, and N is the value that ensures the bit error rate of the signal received at the relay node approaches 0.5.

[0011] Based on the above technical content, in the first signal received by the relay node, the first modulation symbol is a symbol mapped onto the first constellation diagram. The minimum distance between two adjacent constellation points in the same quadrant of this first constellation diagram is less than 2k, which shortens the distance between adjacent constellation points in the same quadrant, increasing the symbol error rate of the signal received at the relay node and indirectly improving the bit error rate, thereby reducing the probability of the relay node eavesdropping on the information of the first modulation symbol. The transmission power of the second modulation symbol in the first signal is redetermined based on a predefined target amplitude ratio and the transmission power of the first modulation symbol, thus the determined transmission power of the second modulation symbol also reduces the probability of the relay node eavesdropping on the information of the second modulation symbol to a certain extent. When the first and second modulation symbols are simultaneously superimposed at the relay node, the probability of the relay node eavesdropping on information can be greatly reduced, thus helping to avoid information leakage. Furthermore, the generation method of the modulation symbols for both the first and second modulation symbols is feasible, not a theoretical modulation method, realizing the practicality of signal design.

[0012] In conjunction with the first aspect, in some possible implementations of the first aspect, the method further includes: a relay node sending first channel information to a first source node, the first channel information being used to indicate the amplitude of a second channel and the noise power at the relay node; or, the first channel information being 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; wherein 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.

[0013] By sending relevant parameters to the first source node through the relay node, the first source node can conveniently and quickly determine the signal-to-noise ratio (SNR) and amplitude ratio α.

[0014] In conjunction with the first aspect, in some possible implementations of the first aspect, the method further includes: a relay node receiving a first request from a first source node, the first request being for requesting first channel information.

[0015] In conjunction with the first aspect, in some possible implementations of the first aspect, the method further includes: a relay node sending second channel information to a second source node, the second channel information being used to indicate the amplitude and phase of the first channel; or, the amplitude ratio and phase difference between the second channel and the first channel; wherein 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.

[0016] The relay node sends the relevant parameters to the second source node, enabling the second source node to conveniently and quickly determine the amplitude ratio 'a' and the phase difference 'Δθ'.

[0017] In conjunction with the first aspect, in some possible implementations of the first aspect, the method further includes: the relay node receiving a second request from the second source node, the second request being for requesting second channel information.

[0018] In conjunction with the first aspect, in some possible implementations of the first aspect, the minimum distance between two adjacent constellation points in the same quadrant is (2-2c)k, 0 < c < 1.

[0019] By introducing parameter c in the first constellation diagram, the distance between two adjacent constellation points in the same quadrant is shortened, which increases the symbol error rate of the signal received at the relay node and indirectly improves the bit error rate, thereby reducing the probability of the relay node eavesdropping on the information of the first modulation symbol.

[0020] In conjunction with the first aspect, in some possible implementations of the first aspect, parameter c is determined by parameter N, SNR, and amplitude ratio a; wherein the value of parameter N is such that the difference between the target bit error rate and 0.5 is no greater than Q(N) / 2, Q(N) is the right tail function of the standard normal distribution; SNR is the SNR of the first channel, and amplitude ratio a is the ratio of the amplitude of the second channel and the second modulation symbol, and the amplitude of the first channel and the first modulation symbol.

[0021] It should be understood that the target bit error rate (BER) is the expected BER of the signal received at the relay node. When this expected BER reaches a certain value, its difference from 0.5 is guaranteed to be no more than 0.1, meaning the relay node can be considered to have almost no information that can be eavesdropped. The difference between the expected BER and 0.5 can be represented by Q(N) / 2. That is, when Q(N) / 2 ≤ 0.1, or Q(N) ≤ 0.2, almost no information can be eavesdropped at the relay node. Q(N) is the right-tail function of the standard normal distribution, and its inverse function Q is referenced. -1 From the curve of (N), we can see that Q -1 (0.2)≈0.8416, that is, Q(0.8416)≈0.2. In other words, when the parameter N>0.8416, it can be guaranteed that the difference between the target bit error rate and 0.5 does not exceed 0.1, and almost no information can be eavesdropped at the relay node.

[0022] By associating the determination of parameter c with parameter N, and the value of parameter N can be such that the difference between the target bit error rate and 0.5 is no greater than Q(N) / 2, the bit error rate of the signal received at the relay node tends to 0.5 after the introduction of parameter c. The relay node can hardly eavesdrop on any information, thus completely avoiding information leakage.

[0023] In conjunction with the first aspect, in some possible implementations of the first aspect, the method of determining the parameter c is related to the modulation method of the first modulation symbol.

[0024] In conjunction with the first aspect, in some possible implementations of the first aspect, the bit sequence corresponding to each constellation point in the first constellation diagram is obtained based on non-Gray code encoding.

[0025] By using non-Gray code encoding for the bit sequence corresponding to each constellation point in the first constellation diagram, the probability of bit transmission errors is increased, thereby further improving the bit error rate of the signal received at the relay node and further avoiding the risk of information leakage.

[0026] In conjunction with the first aspect, in some possible implementations of the first aspect, the correspondence between multiple constellation points and bit sequences in the first constellation diagram is determined based on one of a predefined multiple encoding schemes; the bit sequence includes four bits, and in each of the multiple encoding schemes, 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; in any two of the multiple encoding schemes, the order of the bits corresponding to the multiple constellation points on the I-axis is different, and / or, the order of the bits corresponding to the multiple constellation points on the Q-axis is different.

[0027] By predefining multiple encoding methods, any encoding method can be used in actual encoding to determine the correspondence between multiple constellation points and bit sequences in the first constellation diagram, thus improving the flexibility of the encoding method.

[0028] In conjunction with the first aspect, in some possible implementations of the first aspect, the first modulation symbol is modulated based on quadrature amplitude modulation (QAM).

[0029] In conjunction with the first aspect, in some possible implementations of the first aspect, the second modulation symbol is modulated based on quadrature phase shift keying (QPSK) modulation or binary phase shift keying (BPSK) modulation.

[0030] In conjunction with the first aspect, in some possible implementations of the first aspect, the phase of the second modulation symbol is determined by the phase difference between the second channel and the first channel, wherein the first channel is the channel between the first source node and the relay node, and the second channel is the channel between the second source node and the relay node.

[0031] Optionally, the second modulation symbol is based on quadrature phase shift keying modulation, and the phase θ of the second modulation symbol S2 Phase difference Δθ Integer multiples of.

[0032] For example, the phase θ of the second modulation symbol S2 The following conditions must be met with the phase difference Δθ: l is an integer.

[0033] Optionally, the second modulation symbol is based on binary phase shift keying modulation, and the phase θ of the second modulation symbol S2 Phase difference Δθ An odd multiple of.

[0034] For example, the phase θ of the second modulation symbol S2 The following conditions must be met with the phase difference Δθ: l is an integer.

[0035] By adjusting the phase of the second modulation symbol according to the channel phase difference, the first and second modulation symbols can be aligned, further reducing the probability of information eavesdropping by the relay node. Furthermore, considering the periodicity of the signal, aligning the phases of the first and second modulation symbols in each cycle ensures that the signal received by the relay node in each cycle reduces the risk of information leakage.

[0036] Secondly, this application provides a communication method that can be executed by a first source node, or by a component (such as a chip, chip system, etc.) configured in the first source node, or by a logic module or software capable of implementing all or part of the functions of the first source node. This application does not limit the scope of the method.

[0037] For example, the method includes: a first source node generating a first modulation symbol, the first modulation symbol including a symbol mapped on a first constellation map, wherein there are multiple constellation points in the same quadrant of the first constellation map, and the minimum distance between two adjacent constellation points in the same quadrant is less than 2k, where k is a constellation mapping normalization factor; and the first source node sending the first modulation symbol to a relay node.

[0038] Based on the above 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 of the first constellation diagram is less than 2k, which shortens the distance between two adjacent constellation points in the same quadrant. The distance between two adjacent constellation points will affect the symbol error rate of the first modulation symbol received at the relay node. The smaller the distance, the greater the probability of symbol transmission error, and the greater the symbol error rate. This increases the probability of bit transmission error, thereby increasing the probability of the bit error rate of the signal received at the relay node. This helps to reduce the risk of information being eavesdropped.

[0039] In conjunction with the second aspect, in some possible implementations of the second aspect, the method further includes: a first source node receiving first channel information, the first channel information being used to indicate the amplitude of a second channel and the noise power at a relay node; or, the first channel information being 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; wherein 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.

[0040] In conjunction with the second aspect, in some possible implementations of the second aspect, the method further includes: the first source node sending a first request to the relay node, the first request being used to request first channel information.

[0041] In conjunction with the first aspect, in some possible implementations of the first aspect, the minimum distance between two adjacent constellation points in the same quadrant is (2-2c)k, 0 < c < 1.

[0042] In conjunction with the second aspect, in some possible implementations of the second aspect, the parameter c is determined by the parameter N, SNR, and amplitude ratio a; wherein the value of parameter N is such that the difference between the target bit error rate and 0.5 is no greater than Q(N) / 2, where Q(N) is the right-tail function of the standard normal distribution; SNR is the SNR of the first channel, and amplitude ratio a is the ratio of the amplitude of the second channel and the second modulation symbol, and the amplitude of the first channel and the first modulation symbol.

[0043] In conjunction with the second aspect, in some possible implementations of the second aspect, the method of determining the parameter c is related to the modulation method of the first modulation symbol.

[0044] In conjunction with the second aspect, in some possible implementations of the second aspect, the bit sequence corresponding to each constellation point in the first constellation diagram is obtained based on non-Gray code encoding.

[0045] In conjunction with the second aspect, in some possible implementations of the second aspect, the correspondence between multiple constellation points and bit sequences in the first constellation diagram is determined based on one of a predefined multiple encoding schemes; the bit sequence includes four bits, and in each of the multiple encoding schemes, 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; in any two of the multiple encoding schemes, the order of the bits corresponding to the multiple constellation points on the I-axis is different, and / or, the order of the bits corresponding to the multiple constellation points on the Q-axis is different.

[0046] In conjunction with the second aspect, in some possible implementations of the second aspect, the first modulation symbol is obtained by modulation based on a quadrature amplitude modulation method.

[0047] Thirdly, this application provides a communication method that can be executed by a second source node, or by a component (such as a chip, chip system, etc.) configured in the second source node, or by a logic module or software capable of implementing all or part of the functions of the second source node. This application does not limit the scope of the method.

[0048] For example, the method includes: a second source node generating a second modulation symbol, the second modulation symbol including symbols mapped on a second constellation diagram, wherein there is no more than one constellation point in each quadrant of the second constellation diagram, and the transmission power of the second modulation symbol is determined based on the transmission power of the first modulation symbol; and the second source node transmitting the second modulation symbol to a relay node.

[0049] The transmission power of the second modulation symbol is determined based on the transmission power of the first modulation symbol, further including: the transmission power of the second modulation symbol is determined based on a predefined target amplitude ratio and the transmission power of the first modulation symbol. The target amplitude ratio is less than... At the same time, it can approach a0 with a relatively large value. a0 is determined by the following formula:

[0050]

[0051] Where a0 is the point that satisfies the optimal receiving performance of the second source node, SNR is the signal-to-noise ratio, and N is the value that ensures the bit error rate of the signal received at the relay node approaches 0.5.

[0052] Based on the above technical content, the second modulation symbol generated by the second source node is a symbol mapped on the second constellation diagram. The transmission power of the second modulation symbol is determined according to the predefined target amplitude ratio and the transmission power of the first modulation symbol. Since the predefined target amplitude ratio can guarantee both the anti-eavesdropping performance requirements at the relay node and the receiving performance at the source node, the transmission power of the obtained second modulation symbol can also guarantee both the anti-eavesdropping performance requirements at the relay node and the receiving performance at the source node. This also helps to reduce the probability of the relay node eavesdropping on the information of the second modulation symbol.

[0053] In conjunction with the third aspect, in some possible implementations of the third aspect, the method further includes: a second source node receiving second channel information, the second channel information being used to indicate the amplitude and phase of the first channel; or, the amplitude ratio and phase difference between the second channel and the first channel; wherein 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.

[0054] In conjunction with the third aspect, in some possible implementations of the third aspect, the method further includes: the second source node sending a second request to the relay node, the second request being used to request second channel information.

[0055] In conjunction with the third aspect, in some possible implementations of the third aspect, the second modulation symbol is modulated based on quadrature phase shift keying modulation or binary phase shift keying modulation.

[0056] In conjunction with the third aspect, in some possible implementations of the third aspect, the phase of the second modulation symbol is determined by the phase difference between the second channel and the first channel, wherein the first channel is the channel between the first source node and the relay node, and the second channel is the channel between the second source node and the relay node.

[0057] Optionally, the second modulation symbol is based on quadrature phase shift keying modulation, and the phase θ of the second modulation symbol S2 Phase difference Δθ Integer multiples of.

[0058] For example, the phase θ of the second modulation symbol S2 The following conditions must be met with the phase difference Δθ: l is an integer.

[0059] Optionally, the second modulation symbol is based on binary phase shift keying modulation, and the phase θ of the second modulation symbol S2 Phase difference Δθ The odd multiple of l, where l is an integer.

[0060] For example, the phase θ of the second modulation symbol S2 The following conditions must be met with the phase difference Δθ: l is an integer.

[0061] Fourthly, this application provides a communication apparatus, including modules or units for implementing the methods of the first to third aspects and any possible implementations of the first to third aspects. It should be understood that each module or unit can implement its corresponding function by executing a computer program.

[0062] Fifthly, this application provides a communication device including a processor, the processor being configured to execute the communication methods described in the first to third aspects and any possible implementation thereof.

[0063] The device may further include a memory for storing instructions and data. The memory is coupled to the processor, which, when executing the instructions stored in the memory, can implement the methods described in the foregoing aspects. The device may also include a communication interface for communicating with other devices; exemplary, the communication interface may be a transceiver, circuit, bus, module, or other type of communication interface.

[0064] In a sixth aspect, this application provides a computer-readable storage medium including a computer program that, when run on a computer, causes the computer to implement the methods of the first to third aspects and any possible implementation of the first to third aspects.

[0065] In a seventh aspect, this application provides a computer program product comprising: a computer program (also referred to as code or instructions) that, when executed, causes a computer to perform the methods of the first to third aspects and any possible implementation thereof.

[0066] It should be understood that the fourth to seventh aspects of this application correspond to the technical solutions of the first to third aspects of this application, and the beneficial effects obtained by each aspect and the corresponding feasible implementation are similar, and will not be repeated here. Attached Figure Description

[0067] Figure 1 This is a schematic diagram of a scenario for the communication method provided in an embodiment of this application;

[0068] Figure 2 This is a schematic diagram of another scenario of the communication method provided in the embodiments of this application;

[0069] Figure 3 This is a scenario architecture diagram of the communication method provided in the embodiments of this application;

[0070] Figure 4 This is a schematic flowchart of the communication method provided in the embodiments of this application;

[0071] Figure 5 This is the 16QAM constellation diagram provided in the embodiments of this application;

[0072] Figure 6 This is a 16QAM non-Gray code encoding constellation diagram provided in the embodiments of this application;

[0073] Figure 7 This is the QPSK constellation diagram provided in the embodiments of this application;

[0074] Figure 8 This is a simulation diagram of the bit error rate (BER) at the relay node in a vehicle-to-vehicle (V2V) scenario provided in the embodiments of this application;

[0075] Figure 9 This application provides a simulation diagram of the BER at the source node in a V2V scenario.

[0076] Figure 10 This is a simulation diagram of the BER at a relay node in a satellite mobile communication scenario provided by an embodiment of this application;

[0077] Figure 11 This is a simulation diagram of the BER at the source node in a satellite mobile communication scenario provided by an embodiment of this application;

[0078] Figures 12 to 14 This is a schematic block diagram of a communication device provided in an embodiment of this application. Detailed Implementation

[0079] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0080] The technical solutions provided in this application can be applied to various communication systems, such as 5th generation (5G) mobile communication systems or new radio access technology (NR). The 5G mobile communication system can include non-standalone (NSA) and / or standalone (SA) networking.

[0081] The technical solutions provided in this application can also be applied to machine-type communication (MTC), long-term evolution-machine (LTE-M) technology, device-to-device (D2D) networks, machine-to-machine (M2M) networks, Internet of Things (IoT) networks, or other networks. IoT networks, for example, can include vehicle-to-everything (V2X) networks. The communication methods in V2X systems are collectively referred to as vehicle-to-X (V2X) systems, where X can represent anything. For example, V2X can include vehicle-to-vehicle (V2V) communication, vehicle-to-infrastructure (V2I) communication, vehicle-to-pedestrian (V2P) communication, or vehicle-to-network (V2N) communication. It can also be applied to communication between satellites.

[0082] The technical solution provided in this application can also be applied to future communication systems, such as sixth-generation mobile communication systems. This application does not limit this application.

[0083] Figure 1 This is a schematic diagram of a scenario applicable to the communication method provided in the embodiments of this application. For example... Figure 1The diagram illustrates a V2V communication scenario. This scenario includes vehicles 101, 102, 103, and 104, as well as an airborne mobile relay 105. When the distance between any two vehicles is relatively large, information can be exchanged via the airborne mobile relay. For example, vehicles 101 and 104 can exchange information via airborne mobile relay 105, as can vehicles 102 and 103.

[0084] It should be understood that Figure 1 This is merely an example illustrating one airborne mobile relay and four vehicles. However, this should not be construed as limiting the scope of this application. This V2V scenario may also include more or fewer vehicles, or more airborne mobile relays. The embodiments in this application do not limit this.

[0085] Figure 2 This is a schematic diagram of another scenario for the communication method provided in the embodiments of this application. For example... Figure 2 The image shows a satellite mobile communication scenario. This scenario includes earth station 201, earth station 202, and an artificial Earth satellite 203. Because the distance between earth station 201 and earth station 202 is very far in space, they can exchange information via the artificial map satellite 203.

[0086] It should be understood that Figure 2 This is merely an example, illustrating one artificial Earth satellite and two earth stations. However, this should not be construed as limiting the scope of this application. The satellite mobile communication scenario may also include more earth stations and more artificial Earth satellites. The embodiments in this application do not limit this.

[0087] It should be understood that the choice of relay in this application is not limited to... Figure 1 In-flight mobile relay, or Figure 2 Artificial Earth satellites can also serve as ground relays, and any third-party node capable of forwarding information can act as a relay. This application does not limit this specific instance.

[0088] for Figure 1 and Figure 2 The scenarios shown can all be equivalent to Figure 3 The scenario architecture. The following is combined with... Figure 3 Please provide a detailed explanation.

[0089] Figure 3 This is a scenario architecture diagram of the communication method provided in the embodiments of this application. For example... Figure 3 As shown, S1 is a source node, S2 is another source node, and R is a relay node. S1R h is the channel from source node S1 to relay node R. S2Rh is the channel from source node S2 to relay node R. RS1 For the channel from relay node R to source node S1, h RS2 For the channel from relay node R to source node S2, x S1 The useful signal sent by source node S1, x S2 Useful signals sent by source node S2.

[0090] During communication, source node S1 and source node S2 can exchange information through relay node R. Relay node R acts as a bridge between source node S1 and source node S2, assisting in signal forwarding. Relay node R may be a trusted node that will not eavesdrop on received signals; or it may be an untrusted node that will eavesdrop on received signals. It should be understood that when relay node R is an untrusted node, it may be a communication node with a lower security level that can function normally. It can perform communication functions normally, but it will eavesdrop on received signals without maliciously tampering with them, and is not a malicious active attacker.

[0091] It should be understood that Figure 1 In the V2V scenario shown, the airborne mobile relay 105 can be used as... Figure 3 The relay node R in the system. For any two vehicles, one of them can serve as a relay node R. Figure 3 In the example, vehicle 101 can be source node S1 and vehicle 104 can be source node S2.

[0092] It should also be understood that Figure 2 In the satellite mobile communication scenario shown, artificial Earth satellite 203 can be used as... Figure 3 Relay node R in the system. Either Earth Station 201 or Earth Station 202 can serve as a relay node R. Figure 3 In the example, one can be the source node S1 and the other can be the source node S2. For example, Earth Station 201 can be the source node S1 and Earth Station 202 can be the source node S2.

[0093] Furthermore, such as Figure 3 As shown, in this scenario architecture, the communication process can be divided into two stages, and the following is a detailed explanation of the communication process.

[0094] In the first phase, the source node sends signals to the relay node: S1 and S2 send signals to R, and S1 sends a useful signal x. S1 S2 sends a useful signal x S2 Then the relay node R receives the signal y R for:

[0095]

[0096] Among them, P S1 and P S2 These represent the signal transmission power of source node S1 and the signal transmission power of S2, respectively, n R This represents the noise at point R. Furthermore, as mentioned earlier, h... S1R h is the channel from source node S1 to relay node R. S2R For the channel from source node S2 to relay node R, x S1 The useful signal sent by source node S1, x S2 Useful signals sent by source node S2.

[0097] Where, x S1 and x S2 Each condition is satisfied E is the expected value. For x S1 The conjugate transpose of . For x S2 The conjugate transpose of .

[0098] Where, n R Condition n must also be satisfied R ~CN(0,σ) 2 CN follows a complex Gaussian distribution, σ 2 The variance is the noise power at relay node R.

[0099] It should be understood that the signal received at relay node R is a mixed signal, which includes the useful signal sent by source node S1 and the useful signal sent by source node S2.

[0100] It should also be understood that, without considering information transmission delay, source node S1 and source node S2 simultaneously send signals to relay node R to ensure that relay node R can simultaneously receive the useful signals sent by S1 and S2.

[0101] The second stage involves the relay node forwarding the signal: upon receiving signal y... R Afterwards, relay node R transmits signal y. R To obtain the signal x that needs to be forwarded, magnify or reduce the signal size. R for:

[0102] x R =βy R

[0103] Where β is the power limiting factor, x R Conditions need to be met E is the expected value. For x R The conjugate transpose of P R This represents the transmission power of relay node R.

[0104] It should be understood that the specific value of the power limiting factor β depends on the transmit power P of the relay node R. R The size only needs to satisfy the signal y R The signal x obtained after adjustment R The transmission power is P R That's all.

[0105] The signal x that needs to be forwarded is obtained at relay node R. R Then, the signal x can be... R If the signals are forwarded to source node S1 and source node S2 respectively, then the signals received by source node S1 and source node S2 will satisfy the following conditions:

[0106] y S1 =h RS1 x R +n S1

[0107] and

[0108] y S2 =h RS2 x R +n S2

[0109] Among them, y S1 The signal received by source node S1, y S2 This refers to the signal received by source node S2. S1 For the noise at source node S1, n S2 This represents the noise at the source node S2.

[0110] Signal y is received at source node S1 and source node S2 respectively. S1 and y S2 Then, source node S1 can use self-interference cancellation technology to convert the useful signal x S1 By deleting the signal, the useful signal x sent by the source node S2 can be obtained. S2 Correspondingly, source node S2 can also use self-interference cancellation technology to filter out the useful signal x. S2 By deleting the signal, the useful signal x sent by the source node S1 can be obtained. S1 It should be noted that self-interference cancellation technology is existing technology and will not be discussed further here.

[0111] As can be seen, since the signal obtained by the source node through self-interference cancellation technology does not contain the useful signal it transmits, the useful signal will not affect the receiving performance of the source node regardless of the modulation method used for the useful signal transmitted by the source node.

[0112] It should be understood that Figure 3This is merely an example, showing one relay node and two source nodes. However, this should not be construed as limiting the scope of this application. More relay nodes and more source nodes may be included in this scenario. The embodiments of this application do not limit this.

[0113] As mentioned earlier, current methods for achieving secure communication in bidirectional relay systems design the source node's transmitted signal based on Gaussian signals to improve the secure transmission rate. However, Gaussian signals are difficult to implement practically. Even though some studies utilize channel state information to design the phase and power of commonly used modulation schemes, this only provides a low probability of preventing relay nodes from eavesdropping. In other words, current research cannot achieve a practical signal design approach that significantly reduces the risk of information eavesdropping.

[0114] In view of this, this application provides a communication method in which each source node modulates its own signal before transmitting it, thereby obtaining a first modulation symbol and a second modulation symbol respectively. The first modulation symbol includes a symbol mapped onto a first constellation diagram, where multiple constellation points exist in the same quadrant of the first constellation diagram, and the minimum distance between two adjacent constellation points in the same quadrant is less than 2k, where k is a constellation mapping normalization factor. Because the distance between two adjacent constellation points is reduced, the bit error rate at the relay node can be indirectly improved. The second modulation symbol includes a symbol mapped onto a second constellation diagram, and the transmission power of the second modulation symbol is re-determined based on the transmission power of the first modulation symbol, thereby also reducing the probability of the relay node eavesdropping on information to a certain extent. Therefore, when the first and second modulation symbols are received at the relay node, both modulation symbols can prevent the relay node from eavesdropping on information to a certain extent, thereby greatly reducing the probability of the relay node eavesdropping on information and avoiding information leakage. Furthermore, the generation methods of the modulation symbols are all feasible and not theoretical modulation methods, thus realizing the practicality of signal design.

[0115] The communication method provided in the embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0116] Figure 4 This is a schematic flowchart applicable to the communication method provided in the embodiments of this application. Figure 4 The specific process of this method is illustrated from the perspective of the interaction between the source node and the relay node. Here, the relay node can correspond to... Figure 1 The airborne mobile relay 105 in the V2V scenario shown, or, it can also correspond to... Figure 2 The satellite mobile communication scenario shown includes artificial Earth satellite 203, or it could also correspond to... Figure 3 R in the scenario architecture shown. The first source node and the second source node can correspond to Figure 1 In the V2V scenario shown, any two vehicles, such as vehicle 101 as the first source node and vehicle 104 as the second source node, or, can correspond to... Figure 2 In the satellite mobile communication scenario shown, earth station 201 and earth station 202 can be configured such that earth station 201 acts as the first source node and earth station 202 acts as the second source node. Alternatively, they can also correspond to... Figure 3 In the scenario architecture shown, S1 and S2 can be used as the first source node and S2 can be used as the second source node.

[0117] The method 400 includes steps 410 to 440. These are described in detail below. Figure 4 The steps in method 400 are shown. Steps 410 and 4301 describe the actions performed by the first source node, steps 420 and 4302 describe the actions performed by the second source node, and steps 430 and 440 describe the actions performed by the relay node.

[0118] It should be understood that the first source node, the second source node, and the relay node are merely examples of the execution entities. The various steps in the above method can also be executed by components (such as circuits, chips, chip systems, etc.) deployed in the first source node, the second source node, and the relay node, or 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. This application does not limit this approach.

[0119] In step 410, the first source node generates the first modulation symbol.

[0120] When communicating between the first source node and the second source node, in order to prevent the relay node from eavesdropping on the information, the first source node will generate the first modulation symbol before sending the signal to the relay node.

[0121] The first modulation symbol is obtained based on QAM modulation. Specifically, the first modulation symbol can be obtained based on 16QAM modulation, 64QAM modulation, or any other QAM modulation method.

[0122] The first modulation symbol includes symbols mapped onto a first constellation diagram, in which there are multiple constellation points in the same quadrant, and the minimum distance between two adjacent constellation points in the same quadrant is less than 2k, where k is the constellation mapping normalization factor. Specifically, the minimum distance between two adjacent constellation points in the same quadrant is (2-2c)k, where 0 < c < 1.

[0123] The constellation mapping normalization factor can be determined as follows: The average of the sum of the energies of all constellation points in the constellation diagram is taken, and then the square root is used to obtain the waveform amplitude value. The reciprocal of this amplitude value gives the constellation mapping normalization factor. For example, in a 16-point constellation diagram, there are 4 constellation points with an energy value of 2, 8 constellation points with an energy value of 10, and 4 constellation points with an energy value of 18. The sum of the energies of all constellation points is 160. Since these 16 constellation points are equally distributed (1 / 16), the average energy is 160 ÷ 16 = 10. The waveform amplitude after taking the square root is... Taking its reciprocal, the constellation mapping normalization factor is:

[0124] The energy of a constellation point can be determined by the sum of the squares of the horizontal and vertical coordinates of the constellation point in the constellation diagram.

[0125] Specifically, the first modulation symbol is the symbol mapped onto the first constellation diagram. The exact number of points in the first constellation diagram depends on the QAM modulation scheme used. For example, in 16QAM modulation, the first constellation diagram is a 16-point diagram. Similarly, in 64QAM modulation, the first constellation diagram is a 64-point diagram. Correspondingly, when the first constellation diagram is 16 points, there are 4 points in each quadrant. And when the first constellation diagram is 64 points, there are 16 points in each quadrant.

[0126] The degree to which a relay node can eavesdrop on information can be measured by the bit error rate (BER) of the signal received at the relay node. The closer the BER is to 0.5, the lower the risk of information leakage. It should be understood that BER refers to the proportion of erroneous bits out of the total number of transmitted bits. Each bit can take the value 0 or 1. The probability of each bit being transmitted correctly or incorrectly is 1 / 2. Therefore, the closer the BER of the signal received at the relay node is to 0.5, the less likely the information is to be leaked.

[0127] To improve the bit error rate, this application sets the minimum distance between two adjacent constellation points in the same quadrant of the first constellation diagram to be less than 2k, that is, the minimum distance is (2-2c)k, 0 < c < 1, where k is the constellation mapping normalization factor. The value of k depends on the fact that the first modulation symbol is determined based on the QAM modulation order; different QAM modulation orders result in different values ​​for k.

[0128] The following is combined Figure 5 Let's take the 16QAM constellation chart as an example for explanation.

[0129] Figure 5 This applies to the 16QAM constellation diagram provided in the embodiments of this application. For example... Figure 5 As shown, the I-axis is the unidirectional component axis, and the Q-axis is the orthogonal component axis. Each quadrant contains four symbols, each corresponding to four bits. The coordinates of the four constellation points along the I-axis from the negative to the positive half-axis are -3+c, -1-c, 1+c, and 3-c, respectively. Similarly, the coordinates of the four constellation points along the Q-axis from the negative to the positive half-axis are also -3+c, -1-c, 1+c, and 3-c, respectively. Substituting the constellation mapping normalization factor k, the minimum distance between two adjacent constellation points along either the I-axis or Q-axis in the same quadrant is (2-2c)k. Since c takes values ​​of 0 < c < 1, the minimum distance between two adjacent constellation points along either the I-axis or Q-axis in the same quadrant is greater than 0 and less than 2k.

[0130] In contrast, in a conventional 16QAM constellation diagram, the coordinates of the four constellation points arranged along the I / Q axis from the negative to the positive half-axis are -3, -1, 1, and 3, respectively. It can be seen that the 16QAM constellation diagram used in this application introduces a parameter c. This parameter c can shorten the distance between two adjacent constellation points in the same quadrant. The distance between two adjacent constellation points affects the symbol error ratio (SER) of the signal received at the relay node. The smaller the distance, the greater the probability of symbol transmission errors, and the larger the SER, which in turn increases the probability of bit transmission errors. This improves the BER of the signal received at the relay node, thereby reducing the risk of information eavesdropping.

[0131] It should be understood that with different QAM modulation methods, the number of constellation points on the QAM constellation diagram will vary, and the coordinate values ​​of the constellation points arranged along the I / Q axis will also change from the negative half axis to the positive half axis.

[0132] The specific position of the first modulation symbol on the QAM constellation diagram can be obtained from the following expression for the useful signal:

[0133] x S1 = k×(m+j×n)

[0134] Where, x S1 Let m be the useful signal to be transmitted by the first source node, where m is the real part, corresponding to the I-axis in the QAM constellation diagram, and n is the imaginary part, corresponding to the Q-axis in the QAM constellation diagram. When using a 16QAM constellation diagram, m takes the value of any one of -3+c, -1-c, 1+c, and 3-c, and n takes the value of any one of -3+c, -1-c, 1+c, and 3-c, where 0 < c < 1. k is the constellation mapping normalization factor.

[0135] 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: Figure 5 The symbol in the upper right corner of the 16QAM constellation diagram.

[0136] It should be understood that the range of values ​​for the parameters m and n will differ depending on the QAM modulation method used, and the expression for the parameter k will also change.

[0137] Furthermore, parameter c is determined by parameters N, SNR, and amplitude ratio a.

[0138] The parameter N is set such that the difference between the target bit error rate and 0.5 is no greater than Q(N) / 2, where Q(N) is the right-tail function of the standard normal distribution, and Q(N) / 2 is a monotonically decreasing function of N. It should be understood that this target bit error rate is the expected bit error rate described in the foregoing invention.

[0139] Specifically, the target bit error rate (BER) is the expected BER of the signal received at the relay node. When this expected BER reaches a certain value, its difference from 0.5 is guaranteed to be no more than 0.1, meaning the relay node can be considered to have virtually no information eavesdropped on. The difference between the expected BER and 0.5 can be represented by Q(N) / 2. That is, when Q(N) / 2 ≤ 0.1, or Q(N) ≤ 0.2, almost no information can be eavesdropped on at the relay node. Q(N) is the right-tail function of the standard normal distribution, and its inverse function Q is referenced. -1 From the curve of (N), we can see that Q -1 (0.2)≈0.8416, that is, Q(0.8416)≈0.2. In other words, when parameter N>0.8416, the difference between the target bit error rate and 0.5 can be guaranteed to be no more than 0.1, meaning that almost no information can be eavesdropped at the relay node. It should be noted that the right-tail function of the standard normal distribution is existing technology and will not be discussed further here.

[0140] It should be understood that those skilled in the art can select an appropriate value of N based on the actual requirements for anti-eavesdropping performance. As long as N > 0.8416, the bit error rate of the signal received at the relay node can be made as close to 0.5 as possible, that is, the relay node can hardly eavesdrop on any information.

[0141] This SNR is the SNR of the first channel.

[0142] Specifically, the first channel is the channel between the first source node and the relay node, specifically the channel from the first source node to the relay node. Since the first source node sends the first modulation symbol to the relay node in step 430 below, the first channel here also specifically refers to the channel from the first source node to the relay node.

[0143] The SNR is calculated as follows:

[0144] SNR=(P S1 |h S1R | 2 ) / σ 2

[0145] As mentioned earlier, P S1 h represents the signal transmission power of the first source node. S1R For the channel from the first source node to the relay node, σ 2 This represents the noise power at the relay node.

[0146] The amplitude ratio 'a' is the ratio of the amplitude of the second channel and the second modulation symbol to the amplitude of the first channel and the first modulation symbol.

[0147] Specifically, the second channel is the channel between the second source node and the relay node. Since the second source node generates a second modulation symbol and sends it to the relay node in steps 420 and 430 below, the second channel here also specifically refers to the channel from the second source node to the relay node.

[0148] The amplitude ratio 'a' is calculated as follows:

[0149]

[0150] As mentioned earlier, P S1 and P S2 These represent the signal transmission power of the first source node and the signal transmission power of the second source node, respectively. S2R h is the channel from the second source node to the relay node. S1R This is the channel from the first source node to the relay node.

[0151] After determining parameters N, SNR, and amplitude ratio a according to the above method, parameter c can be further determined. In this application, the method for determining parameter c is related to the modulation method of the first modulation symbol.

[0152] This application takes the 16QAM modulation scheme on which the first modulation symbol is based as an example to illustrate the method for determining parameter c. The specific method for determining parameter c is related to the SNR value in different scenarios, which will be explained in detail below:

[0153] Case (1): In scenarios with a small SNR, such as Figure 1 In the V2V scenario shown, the SNR value is typically small. Therefore, the parameter c can be determined by the following expression:

[0154]

[0155] in,

[0156] According to the aforementioned Figure 3 As described in the communication process, assuming that after receiving the signal forwarded by the relay node, the second source node can use self-interference cancellation technology to delete the second modulation symbol from the received signal, thereby obtaining the first modulation symbol sent by the first source node. At this time, although the deletion of the second modulation symbol does not affect the receiving performance of the second source node, the first modulation symbol will. To reduce the impact of the first modulation symbol on the receiving performance of the second source node, the BER of the first modulation symbol obtained by the second source node needs to be as small as possible, i.e., as close to 0 as possible. Therefore, to minimize the BER of the first modulation symbol at the second source node and thus ensure the receiving performance of the second source node, this application introduces a parameter a0, which satisfies the optimal receiving performance of the second source node. From the above expression for calculating parameter a0, it can be seen that the value of a0 is also affected by the parameter N. Therefore, the parameter a0 in this application is the point that satisfies the requirements for anti-eavesdropping performance, resulting in the optimal receiving performance of the second source node.

[0157] It should be understood that the value of a0 is not limited to the above calculation method. It can also be obtained by direct assignment, such as taking an empirical value. As long as the value assigned to a0 can meet the anti-eavesdropping performance requirements at the relay node and ensure that the receiving performance of the second source node is relatively good.

[0158] Case (2): In scenarios with a large SNR, such as Figure 2 In the satellite mobile communication scenario shown, the SNR is typically high. At this time, It approaches 0 indefinitely. Therefore, the expression for parameter c in (1) above can theoretically be simplified to:

[0159]

[0160] Then, the expression for a0 can also be simplified to At this point, in a communication scenario with a large SNR, the value of a0 is 0.4472, which is the optimal point for the receiving performance of the second source node under the requirement of anti-eavesdropping performance.

[0161] It should be noted that, in When it approaches 0, that is, assuming that... When approximated as 0, the probability of bit transmission error lies precisely between correct and incorrect transmission; that is, it falls within the decision domain, between transmission error and correct transmission. To increase the probability of bit transmission error, the bit transmission needs to cross the decision domain and enter the transmission error outcome. Therefore, this application introduces a correction parameter ε so that the modified expression for c can increase the probability of bit transmission error, thereby improving the BER of the signal received at the relay node. That is, in scenarios with a large SNR, the expression for c is:

[0162]

[0163] Similarly,

[0164] It should be noted that since the simplified expression for c no longer contains the parameter N, and in order to ensure that the BER of the signal received at the relay node tends to 0.5, ε can be set to 0.05.

[0165] It should be understood that, regardless of whether it is case (1) or case (2) above, the expression of the above parameter c will be different for different QAM modulation methods, and the final value of parameter c may also be different.

[0166] As described above, this application introduces parameter c into 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.

[0167] In order to further improve the bit error rate of the signal received at the relay node, the bit sequence corresponding to each constellation point in the first constellation diagram is obtained based on non-Gray code encoding.

[0168] Specifically, each constellation point, or each symbol, can generate a preset number of bits, called a bit sequence. Conventional encoding methods for the bit sequences corresponding to constellation points typically use Gray code, meaning that only one bit differs between the bit sequences corresponding to two adjacent constellation points, thus minimizing the risk of errors during bit transmission. However, to increase the bit error rate of the signal received at the relay node, this application employs non-Gray code encoding for the bit sequences corresponding to constellation points. This means that at least two bits differ between the bit sequences corresponding to two adjacent constellation points. For example, for constellation points in 16QAM, within the same quadrant, two bits may differ between the bit sequences corresponding to two adjacent constellation points. For constellation points in 64QAM, three bits may differ between the bit sequences corresponding to two adjacent constellation points within the same quadrant. Compared to conventional Gray code mapping, the increased number of different bit values ​​increases the probability of bit transmission errors, thereby increasing the bit error rate of the signal received at the relay node and further reducing the risk of eavesdropping on the signal by the relay node. It should be noted that Gray code encoding is an existing technology and will not be discussed further here.

[0169] The following combination Figure 6 Explanation of non-Gray code encoding.

[0170] Figure 6 This is the 16QAM non-Gray code encoded constellation diagram applicable to the embodiments of this application. For example... Figure 6 As shown, the I-axis is the unidirectional component axis, and the Q-axis is the orthogonal component axis. Each quadrant contains four symbols, and each symbol can generate four bits. It can be seen that for any two adjacent constellation points within the same quadrant, two bits differ in value. For example, in the upper right quadrant, the first two bits of bit sequence 0110 and bit sequence 1010 differ, while the last two bits of bit sequence 0110 and bit sequence 0101 differ. Similarly, in the lower left quadrant, the first two bits of bit sequence 0011 and bit sequence 1111 differ, while the last two bits of bit sequence 0011 and bit sequence 0000 differ. Taking bit sequences 0011 and 0000 as examples, the probability of bit transmission errors increases due to the difference in the last two bits between these two bit sequences. Consequently, the BER of the signal received at the relay node increases, and the probability of eavesdropping at the relay node decreases.

[0171] In one possible implementation, the correspondence between multiple constellation points and bit sequences in the first constellation diagram is determined based on one of a predefined multiple encoding schemes; the bit sequence includes four bits, and in each of the multiple encoding schemes, 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; in any two of the multiple encoding schemes, the order of the bits corresponding to the multiple constellation points on the I-axis is different, and / or, the order of the bits corresponding to the multiple constellation points on the Q-axis is different.

[0172] Specifically, with Figure 6 Taking the 16QAM non-Gray code constellation diagram as an example, 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 (-3+c)k, (-1-c)k, (1+c)k, and (3-c)k, respectively, corresponding to the two bits 00, 11, 01, and 10. The coordinates of each constellation point on the Q-axis from the negative half-axis to the positive half-axis are also (-3+c)k, (-1-c)k, (1+c)k, and (3-c)k, respectively, corresponding to the two bits 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 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 the coordinate "-3+c" on the I-axis, and the last two bits "10" correspond to the coordinate "3-c" on the Q-axis.

[0173] The sorting method of the bits corresponding to the coordinate points on the I-axis and Q-axis is not limited to... Figure 6 One of the methods shown is described above. This application predefines multiple encoding methods, and the correspondence between multiple constellation points and bit sequences in the first constellation diagram can be any one of these predefinitive encoding methods. Figure 6For example, the bits "00" and "11" corresponding to constellation points on the negative half of the I-axis can be interchanged, and the bits "01" and "00" corresponding to them on the positive half-axis can be interchanged. Thus, four encoding schemes can be predefined. Similarly, the bits on the negative and positive half-axes of the I-axis can also be interchanged. For instance, the bits "00" corresponding to a constellation point on the negative half-axis and "10" corresponding to it on the positive half-axis can be interchanged, and the bits "11" corresponding to it on the negative half-axis and "01" corresponding to it on the positive half-axis can be interchanged. This again predefines four encoding schemes. In other words, for one side of the I-axis, eight encoding schemes can be predefined. Correspondingly, there are also eight predefined encoding schemes for the Q-axis. Therefore, for a 16QAM non-Gray code encoded constellation diagram, 64 (8×8) encoding schemes can be predefined, and the correspondence between multiple constellation points and bit sequences in the 16QAM constellation diagram is determined by one of these 64 predefined encoding schemes. Obviously, in any pairwise encoding method, the order of the bit sequences corresponding to the coordinates of multiple constellation points on the I-axis and / or Q-axis will also be different.

[0174] It should be understood that the number of predefined coding schemes will vary depending on the QAM modulation method used. For example, the number of predefined coding schemes will be greater for a 64QAM constellation.

[0175] Furthermore, as explained above, the calculation of SNR and amplitude ratio α involves several parameters, such as channel amplitude and noise power, which can be obtained as follows:

[0176] The first source node sends a first request to the relay node, which requests first channel information. Correspondingly, the relay node receives the first request from the first source node.

[0177] It should be understood that the first source node can obtain these parameters not only through the method of sending the first request described above, but also through relay pre-configuration or network configuration. Relay pre-configuration refers to the relay node pre-configuring relevant parameters for the source node, while network configuration refers to the pre-determining of the content of the transmitted information parameters in the wireless network. This application does not limit the specific method by which the first source node obtains the above parameters.

[0178] After receiving the first request, the relay node can send different first channel information to the first source node depending on the situation. The following is a classification explanation:

[0179] Case (1): In scenarios with a small SNR, such as Figure 1 In the V2V scenario shown,

[0180] The relay node transmits first channel information, which indicates the amplitude |h| of the second channel. S2R | and the noise power σ at the relay node 2 .

[0181] Alternatively, the first channel information can be used to indicate the amplitude ratio |h| of the second channel to the first channel. S2R / h S1R | and the ratio of the square of the first channel amplitude to the noise power at the relay node |h S1R | 2 / σ 2 .

[0182] Case (2): In scenarios with a large SNR, such as Figure 2 In the satellite mobile communication scenario shown,

[0183] The relay node transmits first channel information, which indicates the amplitude |h| of the second channel. S2R |

[0184] Alternatively, the first channel information can be used to indicate the amplitude ratio |h| of the second channel to the first channel. S2R / h S1R |

[0185] In both cases (1) and (2), the first channel is the channel between the first source node and the relay node, specifically the channel from the first source node to the relay node, and the second channel is the channel between the second source node and the relay node, specifically the channel from the second source node to the relay node.

[0186] In both case (1) and case (2), the first source node receives the first channel information and thus determines the SNR and amplitude ratio a based on the parameters indicated by the first channel information.

[0187] It should be understood that since the signal transmission power of the source node is controlled by the source node itself when it transmits a signal, 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.

[0188] In one possible implementation, the first channel information may further include the ID of the second source node and a timestamp, the timestamp indicating the time when the relay node acquired the parameters indicated in the first channel information. Specifically, the first source node may send a pre-agreed pilot signal to the relay node, which can then obtain the relevant parameters through channel estimation, and thus also obtain the acquisition time of these parameters.

[0189] In one possible implementation, the first channel information is carried in a sidelink (SL) message, a Uu interface message, or uplink control information (UCI). Here, the Uu interface refers to the common interface used to implement communication between user equipment (UE) and the evolved universal terrestrial radio access network (E-UTRAN).

[0190] It should be understood that if there is no base station in the first source node and relay node, the first channel information is carried in the SL message; if the first source node is a base station, the first channel information is carried in the Uu interface message or the UCI.

[0191] In step 420, the second source node generates the second modulation symbol.

[0192] When communicating between the first source node and the second source node, in order to prevent the relay node from eavesdropping on the information, the second source node will also generate a second modulation symbol before sending a signal to the relay node.

[0193] The second modulation symbol is obtained by modulation based on QPSK or BPSK modulation.

[0194] The second modulation symbol includes a symbol mapped onto a second constellation diagram, wherein there is no more than one constellation point in each quadrant of the second constellation diagram, and the transmission power of the second modulation symbol is determined based on the transmission power of the first modulation symbol.

[0195] The transmission power of the second modulation symbol is determined based on the transmission power of the first modulation symbol, further including: the transmission power of the second modulation symbol is determined based on a predefined target amplitude ratio and the transmission power of the first modulation symbol. The target amplitude ratio is less than... At the same time, it can approach a0 with a relatively large value. a0 is determined by the aforementioned formula:

[0196]

[0197] Specifically, the second modulation symbol is the symbol mapped onto the second constellation diagram. The number of constellation points in the second constellation diagram varies depending on the modulation scheme on which the second modulation symbol is based. For example, when the modulation scheme is QPSK, the second constellation diagram is a 4-point constellation diagram. Figure 7 This refers to the QPSK constellation diagram provided in the embodiments of this application. For example... Figure 7As shown, the I-axis is the same-direction component axis, and the Q-axis is the quadrature component axis. It can be seen that, whether it is the QPSK modulation of this scheme or the conventional QPSK modulation scheme, there is one symbol in each quadrant. For example, when the modulation method is BPSK modulation, the second constellation diagram is also a 2-point constellation diagram.

[0198] The specific position of the second modulation symbol on the constellation diagram can be obtained from the following expression for the useful signal:

[0199]

[0200] Where, x S2 The useful signal to be transmitted by the second source node is represented by p, which is the real part and corresponds to the I-axis in the constellation diagram, and q, which is the imaginary part and corresponds to the Q-axis in the constellation diagram. When using a QPSK constellation diagram, the values ​​of p and q are -1 or 1, respectively.

[0201] Among them, P S θ'2 represents the transmit power of the second modulation symbol. S2 The phase of the second modulation symbol.

[0202] It should be understood that the values ​​of p and q will change accordingly depending on the modulation method.

[0203] The transmission power P S ′2 is not the known, default signal transmission power P of the second source node as mentioned above. S2 Instead, the transmit power is re-determined based on a predefined target amplitude ratio and the transmit power of the first modulation symbol, which can be obtained in the following way:

[0204] The second source node first determines the amplitude ratio 'a', as follows:

[0205]

[0206] As mentioned earlier, P S1 P represents the signal transmission power of the first source node. S2 h represents the signal transmission power of the second source node. S2R h is the channel from the second source node to the relay node. S1R This refers to the channel from the first source node to the relay node. It should be noted that P... S1 and P S2 All are default, known signal transmission power.

[0207] To ensure that the bit error rate of the signal received at the relay node approaches 0.5, according to the expression for calculating parameter c in step 410 above, it can be found that only when the amplitude ratio a is less than... Only then can parameter c be calculated to meet the anti-eavesdropping requirements at the relay node. Furthermore, as pointed out in the preceding analysis, parameter a0 is the point where the second source node's receiving performance is optimal under the anti-eavesdropping performance requirements. Therefore, the closer the amplitude ratio a is to a0, the better the receiving performance of the second source node is guaranteed. Also, for the first source node, the larger the value of the amplitude ratio a, the better the receiving performance of the first source node. That is, the condition for the amplitude ratio a is: the value of the amplitude ratio a is less than... At the same time, it can also approach a0 with a relatively large value. In this way, it can guarantee both the anti-eavesdropping performance requirements at the relay node and the reception performance of the source node. For ease of distinction and explanation, the amplitude ratio determined according to the above value conditions will be denoted as the target amplitude ratio a′.

[0208] Therefore, after determining the amplitude ratio 'a' at the second source node, the amplitude ratio 'a' is reassigned according to the above-mentioned value conditions to obtain the target amplitude ratio 'a', and then the transmit power P of the second modulation symbol is re-determined. S '2. As follows:

[0209]

[0210] Where a′ is the target amplitude ratio, P S ′2 represents the transmit power of the second modulation symbol, P S1 This is the signal transmission power of the first source node, which is also the transmission power of the first modulation symbol. This transmission power is the default transmission power. S2R h is the channel from the second source node to the relay node. S1R This is the channel from the first source node to the relay node.

[0211] It can be seen that, since the target amplitude ratio a′ can guarantee both the anti-eavesdropping performance requirements at the relay node and the receiving performance at the source node, the redefined transmit power P of the second modulation symbol... S This configuration '2' ensures both the anti-eavesdropping performance requirements at the relay node and the reception performance at the source node. In other words, the second source node transmits the signal at the default power P. S2 Adjustments are made to regain the transmit power P. S ′2, thus ensuring both the anti-eavesdropping performance requirements at the relay node and the receiving performance of the source node.

[0212] The phase θ of the second modulation symbol S2 The phase difference Δθ between the second channel and the first channel is determined as follows:

[0213] Δθ=angle(h S2R / h S1R )

[0214] Where angle is the radian value used to calculate the phase angle of a complex matrix, and h S2R h is the channel from the second source node to the relay node. S1R This is the channel from the first source node to the relay node.

[0215] Furthermore, when the second modulation symbol is based on QPSK modulation, the phase θ of the second modulation symbol S2 Phase difference Δθ Integer multiples of.

[0216] For example, the phase θ of the second modulation symbol S2 The following conditions must be met with the phase difference Δθ:

[0217] l is an integer.

[0218] When the second modulation symbol is based on BPSK modulation, the phase θ of the second modulation symbol S2 Phase difference Δθ An odd multiple of.

[0219] For example, the phase θ of the second modulation symbol S2 The following conditions must be met with the phase difference Δθ: l is an integer.

[0220] by Figure 7 Taking QPSK modulation as an example, whether for this scheme or the conventional scheme, the distance from the constellation point to the origin represents the signal's transmit power, and the angle of rotation of the constellation point represents the signal's phase. It can be seen that, under the conventional scheme, the transmit power of the constellation point is... In this scheme, the transmission power of the second modulation symbol is greater than that of the modulation symbol in the conventional scheme, as mentioned above. Furthermore, the phase of the second modulation symbol in this scheme is rotated counterclockwise compared to the phase of the modulation symbol in the conventional scheme. That is, the second modulation symbol generated in this application is improved in both phase and transmission power compared to the conventional scheme. Moreover, as can be seen from the foregoing description, the transmission power of the second modulation symbol redefined in this scheme can guarantee both the anti-eavesdropping performance requirements at the relay node and the receiving performance at the source node, and the redefined phase also reduces the probability of the relay node eavesdropping on information. It should be understood that... Figure 7 The conventional scheme is to obtain the modulation symbol according to the existing QPSK modulation. The conventional QPSK modulation scheme will not be described in detail here.

[0221] Furthermore, as explained above, the calculation of the amplitude ratio 'a' involves several parameters, such as the channel amplitude, which can be obtained as follows:

[0222] The second source node sends a second request to the relay node, which requests second channel information. Correspondingly, the relay node receives the second request from the second source node.

[0223] Similarly, the second source node can obtain these parameters not only through the method of sending a second request, but also through relay pre-configuration or network configuration. Relay pre-configuration involves the relay node pre-configuring relevant parameters for the source node, while network configuration involves pre-determining the content of the transmitted information parameters in a wireless network. This application does not limit the method by which the second source node obtains the above parameters.

[0224] After receiving the second request, the relay node sends second channel information to the second source node. This second channel information is used to indicate the amplitude |h of the first channel. S1R | and the phase angle (h) of the first channel S1R ); or, the amplitude ratio of the second channel to the first channel |h S2R / h S1R | and phase difference angle(h) S2R / h S1R );

[0225] The first channel is the channel between the first source node and the relay node, specifically the channel from the first source node to the relay node. The second channel is the channel between the second source node and the relay node, specifically the channel from the second source node to the relay node.

[0226] Accordingly, the first source node receives the second channel information, and thus determines the amplitude ratio a and the phase difference Δθ based on the parameters indicated by the second channel information.

[0227] In one possible implementation, the second channel information may further include the ID of the first source node and a timestamp, the timestamp indicating the time when the relay node acquired the parameters indicated in the second channel information. Specifically, the second source node may send a pre-agreed pilot signal to the relay node, which can then obtain the relevant parameters through channel estimation, and thus also obtain the acquisition time of these parameters.

[0228] In one possible implementation, the second channel information is carried in the sidelink SL radio resource control (RRC) reconfiguration message, the SL capability transmission message, the SL medium access control (MAC) control element (CE), or the sidelink control information (SCI).

[0229] In step 430, the relay node receives the first signal.

[0230] Specifically, the first signal includes a first modulation symbol from a first source node and a second modulation symbol from a second source node. After receiving the first signal, the relay node, corresponding to steps 410 and 420 above, performs the following steps: Step 430 includes step 4301, where the first source node sends the first modulation symbol to the relay node, and step 4302, where the second source node sends the second modulation symbol to the relay node. In one possible design, the source node with a better channel link can act as the first source node and generate the first modulation symbol using the method described in step 410; the source node with a poorer channel link can act as the second source node and generate the second modulation symbol using the method described in step 420.

[0231] It should be understood that, based on the foregoing... Figure 3 As described above, although the first signal received by the relay node includes a first modulation symbol and a second modulation symbol, the first and second modulation symbols are obtained by the first and second source nodes respectively through processing the signal to be transmitted by executing steps 410 and 420 above. The relay node cannot parse the first and second modulation symbols. In other words, the first signal received by the relay node is a mixed signal of the first and second modulation symbols.

[0232] Specifically, since the first modulation symbol is obtained based on QAM modulation, a parameter 'c' is introduced into the QAM constellation diagram. This parameter 'c' shortens the distance between two adjacent constellation points in the same quadrant, increasing the symbol error rate (BER) of the signal received at the relay node, and indirectly increasing the bit error rate (BER), thus increasing the BER of the signal received at the relay node. The determination of this parameter 'c' is related to parameter 'N', which ensures that the BER of the signal received at the relay node is as close to 0.5 as possible. In other words, the introduction of parameter 'c' guarantees that almost no information can be eavesdropped at the relay node. Furthermore, the bit sequence corresponding to the constellation points in the QAM constellation diagram is also obtained based on non-Gray code, further improving the BER at the relay node. The transmission power of the second modulation symbol is also redetermined based on a predefined target amplitude ratio and the transmission power of the first modulation symbol. The predefined target amplitude ratio ensures the anti-eavesdropping performance requirements at the relay node, and the redetermined phase of the second modulation symbol further reduces the probability of information eavesdropping at the relay node. Therefore, when the first and second modulation symbols act simultaneously on the relay node, the relay node can barely eavesdrop on any information. Furthermore, the first source node uses a first constellation diagram to map the first modulation symbol, and the second source node uses a second constellation diagram to map the second modulation symbol. Since the amplitudes of all symbols in the second constellation diagram are consistent, the superposition of the first and second modulation symbols at the relay node ensures that the interference amplitude caused by the second modulation symbol on the first modulation symbol is consistent, thus achieving a uniform anti-eavesdropping effect.

[0233] The following combination Figures 8 to 11 The BER simulation results under different scenarios are explained below:

[0234] Case (1): In scenarios with a small SNR, such as Figure 1 The V2V scenario shown.

[0235] Figure 8 This is a simulation diagram of the BER (Bit Rate) at relay nodes in the V2V scenario provided in the embodiments of this application. For example... Figure 8 As shown, curve A represents the simulation curve of this scheme, curve B represents the simulation curve of the Gaussian scheme, RBER1_S1 represents the BER of the first and third bits corresponding to the first modulation symbol sent by the first source node at the relay node, RBER2_S1 represents the BER of the second and fourth bits corresponding to the first modulation symbol sent by the first source node at the relay node, and RBER_S2 represents the BER of the second modulation symbol sent by the second source node at the relay node.

[0236] Depend on Figure 8 As can be seen, with parameters N=2.5 and SNR=25dB, when the amplitude ratio 'a' is within the range of 0.35 to 0.6, for curve A of this scheme, whether it is the RBER1_S1 curve, RBER2_S1 curve, or RBER_S2 curve, they basically overlap, and the BER at the relay node is close to 0.5, which can almost completely prevent relay nodes from eavesdropping on the signal. However, for curve B of the Gaussian scheme, whether it is the RBER1_S1 curve, RBER2_S1 curve, or RBER_S2 curve, the BER at the relay node is significantly less than 0.5, but greater than 0.1, which can only slightly prevent relay nodes from eavesdropping on the signal. Therefore, the scheme of this application is significantly superior to the Gaussian scheme used in the prior art. Furthermore, when using this scheme, when the value of 'a' is within the range of 0.35 to 0.6, it can almost completely prevent relay nodes from eavesdropping on the signal.

[0237] Figure 9 This is a simulation diagram applicable to the BER at the source node in the V2V scenario provided in the embodiments of this application. For example... Figure 9 As shown, curve A represents the simulation curve of this scheme, curve B represents the simulation curve of the Gaussian scheme, BER1_S2 represents the BER of the first bit and the third bit corresponding to the first modulation symbol sent by the first source node at the second source node, BER2_S2 represents the BER of the second bit and the fourth bit corresponding to the first modulation symbol sent by the first source node at the second source node, and BER_S1 represents the BER of the second modulation symbol sent by the second source node at the first source node.

[0238] Depend on Figure 9 As can be seen, with parameter N = 2.5 and SNR = 25dB, similarly, when the amplitude ratio 'a' is in the range of 0.35 to 0.6, curve A of this scheme and curve B of the Gaussian scheme basically coincide. Whether it's the BER1_S2 curve, BER2_S2 curve, or BER_S1 curve, they also basically coincide within this range, and the BER at the source node is close to 0. Therefore, when the value of 'a' is in the range of 0.35 to 0.6, this scheme can also effectively guarantee the receiving performance of the source node.

[0239] Case (2): In scenarios with a large SNR, such as Figure 2 The image shows a satellite mobile communication scenario.

[0240] Figure 10 This is a simulation diagram of the BER (Breakpoint) at a relay node in a satellite mobile communication scenario provided in the embodiments of this application. For example... Figure 10 As shown, curve A represents the simulation curve of this scheme, curve B represents the simulation curve of the Gaussian scheme, RBER1_S1 represents the BER of the first and third bits corresponding to the first modulation symbol sent by the first source node at the relay node, RBER2_S1 represents the BER of the second and fourth bits corresponding to the first modulation symbol sent by the first source node at the relay node, and RBER_S2 represents the BER of the second modulation symbol sent by the second source node at the relay node.

[0241] Depend on Figure 10 As can be seen, with compensation parameter ε = 0.05 and SNR = 50dB, when the amplitude ratio 'a' is within the range of 0.05 to 0.95, for curve A of this scheme, whether it is the RBER1_S1 curve, RBER2_S1 curve, or RBER_S2 curve, they basically overlap, and the BER at the relay node is close to 0.5, which can almost completely prevent relay nodes from eavesdropping on the signal. However, for curve B of the Gaussian scheme, whether it is the RBER1_S1 curve, RBER2_S1 curve, or RBER_S2 curve, the BER at the relay node is significantly less than 0.5, but greater than 0.1, which can only slightly prevent relay nodes from eavesdropping on the signal. Therefore, the scheme of this application is significantly superior to the Gaussian scheme used in the prior art. Furthermore, when using the scheme of this application, when the value of 'a' is within the range of 0.05 to 0.95, it can almost completely prevent relay nodes from eavesdropping on the signal.

[0242] Figure 11 This is a simulation diagram of the BER at the source node in the satellite mobile communication scenario provided in the embodiments of this application. For example... Figure 11As shown, curve A represents the simulation curve of this scheme, curve B represents the simulation curve of the Gaussian scheme, BER1_S2 represents the BER of the first bit and the third bit corresponding to the first modulation symbol sent by the first source node at the second source node, BER2_S2 represents the BER of the second bit and the fourth bit corresponding to the first modulation symbol sent by the first source node at the second source node, and BER_S1 represents the BER of the second modulation symbol sent by the second source node at the first source node.

[0243] Depend on Figure 11 As can be seen, with compensation parameter ε = 0.05 and SNR = 50dB, similarly, when the amplitude ratio 'a' is in the range of 0.05 to 0.95, curve A of this scheme and curve B of the Gaussian scheme basically coincide. Whether it's the BER1_S2 curve, BER2_S2 curve, or BER_S1 curve, they also basically coincide within this range, and the BER at the source node is basically close to 0. Therefore, when the value of 'a' is in the range of 0.05 to 0.95, this application can also effectively guarantee the receiving performance of the source node.

[0244] In step 440, the relay node forwards the first signal.

[0245] For an explanation of step 440, please refer to the aforementioned explanation. Figure 3 The second phase of the communication process will be introduced and understood here, and will not be repeated here.

[0246] Based on the above scheme, the first modulation symbol sent from the first source node to the relay node is obtained by QAM modulation. A parameter 'c' is introduced into the QAM constellation diagram, which shortens the distance between adjacent constellation points in the same quadrant, making the minimum distance between two adjacent constellation points in the same quadrant less than 2k, thereby increasing the bit error rate (BER) of the signal received at the relay node to a certain extent. The determination of parameter 'c' is influenced by parameter 'N', which is a parameter that makes the BER of the signal received at the relay node as close as possible to 0.5. Therefore, the introduction of parameter 'c' is to ensure that almost no information can be eavesdropped at the relay node. Furthermore, the bit sequence of the constellation points in the QAM constellation diagram is obtained based on non-Gray code, further improving the BER at the relay node. The transmission power of the second modulation symbol is also redetermined based on a predefined target amplitude ratio and the transmission power of the first modulation symbol. The predefined target amplitude ratio ensures the anti-eavesdropping performance requirements at the relay node, and the redetermined phase of the second modulation symbol further reduces the probability of information eavesdropping by the relay node. Therefore, when the first modulation symbol and the second modulation symbol are applied simultaneously to the relay node, the relay node can barely eavesdrop on any information from the received mixed signal, thus completely preventing the relay node from eavesdropping on the information. Furthermore, the signal design scheme for the source node in this application is entirely feasible and also realizes the practical application of signal design.

[0247] The above, combined with Figures 4 to 11 The methods provided in the embodiments of this application are described in detail below. Hereinafter, in conjunction with... Figures 12 to 14 The apparatus provided in the embodiments of this application will be described in detail.

[0248] Figure 12 This is a schematic block diagram of a communication device provided in an embodiment of this application. The communication device 1200 can correspond to a relay node in the method embodiment. For example, the communication device 1200 can be a relay node, a component within the relay node (such as a circuit, chip, chip system, etc.), or a logic module or software capable of implementing all or part of the relay node's functions. The relay node can, for example, be... Figure 1 The airborne mobile relay 105, or Figure 2 The artificial Earth satellite 203 is mentioned. This application does not limit the scope of the embodiments.

[0249] like Figure 12 As shown, the communication device 1200 may include a receiving unit 1210 and a processing unit 1220. Each unit in the device 1200 can be used to implement... Figure 4The corresponding process executed by the relay node in method 400 is shown. For example, receiving unit 1210 can be used to execute step 430 in method 400, and processing unit 1220 can be used to execute step 440 in method 400.

[0250] Specifically, the receiving unit 1210 can be used to receive a first signal, which includes a first modulation symbol from a first source node and a second modulation symbol from a second source node; wherein, the first modulation symbol includes a symbol mapped on a first constellation diagram, in which there are multiple constellation points in the same quadrant of the first constellation diagram, and the minimum distance between two adjacent constellation points in the same quadrant is less than 2k, where k is a constellation mapping normalization factor; the second modulation symbol includes a symbol mapped on a second constellation diagram, in which there is no more than one constellation point in each quadrant of the second constellation diagram, and the transmission power of the second modulation symbol is determined based on the transmission power of the first modulation symbol. The processing unit 1220 can be used to forward the first signal.

[0251] Optionally, the processing unit 1220 can also be used to send first channel information to the first source node, the first channel information being used to indicate the amplitude of the second channel and the noise power at the relay node; or, the first channel information being 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; wherein, the first channel is the channel between the first source node and the relay node, and the second channel is the channel between the second source node and the relay node.

[0252] Optionally, the receiving unit 1210 can also be used to receive a first request from the first source node, the first request being used to request first channel information.

[0253] Optionally, the processing unit 1220 can also be used to send second channel information to the second source node, the second channel information being used to indicate the amplitude and phase of the first channel; or, the amplitude ratio and phase difference between the second channel and the first channel; wherein, the first channel is the channel between the first source node and the relay node, and the second channel is the channel between the second source node and the relay node.

[0254] Optionally, the receiving unit 1210 can also be used to receive a second request from the second source node, the second request being used to request second channel information.

[0255] Optionally, the minimum distance between two adjacent constellation points in the same quadrant is (2-2c)k, where 0 < c < 1.

[0256] Optionally, the parameter c is determined by the parameter N, SNR, and 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 no greater than Q(N) / 2, where Q(N) is the right tail function of the 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 and the second modulation symbol, and the amplitude of the first channel and the first modulation symbol.

[0257] Optionally, the method of determining the parameter c is related to the modulation method of the first modulation symbol.

[0258] Optionally, the bit sequence corresponding to each constellation point in the first constellation diagram is obtained based on non-Gray code encoding.

[0259] Optionally, the correspondence between multiple constellation points and bit sequences in the first constellation diagram is determined based on one of a predefined multiple encoding methods; the bit sequence includes four bits, and in each of the multiple encoding methods, 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; in any two of the multiple encoding methods, the order of the bits corresponding to multiple constellation points on the I-axis is different, and / or, the order of the bits corresponding to multiple constellation points on the Q-axis is different.

[0260] Optionally, the first modulation symbol is obtained by modulation based on quadrature amplitude modulation.

[0261] Optionally, the second modulation symbol is obtained by modulation based on quadrature phase shift keying modulation or binary phase shift keying modulation.

[0262] Optionally, the phase of the second modulation symbol is determined by the phase difference between the second channel and the first channel, wherein the first channel is the channel between the first source node and the relay node, and the second channel is the channel between the second source node and the relay node.

[0263] Optionally, the second modulation symbol is based on quadrature phase shift keying modulation, and the phase θ of the second modulation symbol S2 Phase difference Δθ Integer multiples of.

[0264] Optionally, the second modulation symbol is based on binary phase shift keying modulation, and the phase θ of the second modulation symbol S2 Phase difference Δθ An odd multiple of.

[0265] It should be understood that the division of units in the embodiments of this application is illustrative and only represents a logical functional division. In actual implementation, there may be other division methods. Furthermore, the functional units in the various embodiments of this application can be integrated into a single processor, exist as separate physical units, or be integrated into one unit by two or more units. The integrated units described above can be implemented in hardware or as software functional units.

[0266] Figure 13 This is another schematic block diagram of the communication device provided in the embodiments of this application. The communication device 1300 can correspond to the first source node or the second source node in the method embodiments. For example, the communication device 1300 can be the first source node or the second source node, or it can be a component (such as a circuit, chip, chip system, etc.) in the first source node or the second source node, or it can be 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 can, for example, be... Figure 1 Any vehicle in the list, such as vehicle 101, or Figure 2 Any earth station in the network, such as earth station 201. The second source node can be... Figure 1 Any vehicle other than the vehicle that serves as the first source node, such as vehicle 104, or Figure 2 Earth station 202 in the example. This application does not limit this aspect.

[0267] like Figure 13 As shown, the communication device 1300 may include a generation unit 1310 and a transceiver unit 1320.

[0268] In one possible design, the units in the device 1300 can be used to implement Figure 4 The corresponding process executed by the first source node in the method 400 shown. For example, the generation unit 1310 can be used to execute step 410 in method 400, and the transceiver unit 1320 can be used to execute steps 4301 and 440 in method 400.

[0269] For example, when the device 1300 is used to implement the function of the first source node in the method provided in the embodiments of this application, the generation unit 1310 can be used to generate a first modulation symbol, which includes a symbol mapped on a first constellation diagram. The first constellation diagram contains multiple constellation points in the same quadrant, and the minimum distance between two adjacent constellation points in the same quadrant is less than 2k, where k is a constellation mapping normalization factor. The transceiver unit 1320 can be used to send the first modulation symbol to a relay node.

[0270] Optionally, the transceiver unit 1320 is further configured to receive first channel information, which is used to indicate the amplitude 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; wherein, the first channel is the channel between the first source node and the relay node, and the second channel is the channel between the second source node and the relay node.

[0271] Optionally, the transceiver unit 1320 is further configured to send a first request to the relay node, the first request being used to request first channel information.

[0272] Optionally, the minimum distance between two adjacent constellation points in the same quadrant is (2-2c)k, where 0 < c < 1.

[0273] Optionally, parameter c is determined by parameter N, SNR, and amplitude ratio a; wherein, the value of parameter N is such that the difference between the target bit error rate and 0.5 is no greater than Q(N) / 2, where Q(N) is the right tail function of the standard normal distribution; SNR is the SNR of the first channel, and amplitude ratio a is the ratio of the amplitude of the second channel and the second modulation symbol, and the amplitude of the first channel and the first modulation symbol.

[0274] Optionally, the method of determining the parameter c is related to the modulation method of the first modulation symbol.

[0275] Optionally, the bit sequence corresponding to each constellation point in the first constellation diagram is obtained based on non-Gray code encoding.

[0276] Optionally, the correspondence between multiple constellation points and bit sequences in the first constellation diagram is determined based on one of a predefined multiple encoding methods; the bit sequence includes four bits, and in each of the multiple encoding methods, 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; in any two of the multiple encoding methods, the order of the bits corresponding to multiple constellation points on the I-axis is different, and / or, the order of the bits corresponding to multiple constellation points on the Q-axis is different.

[0277] Optionally, the first modulation symbol is obtained by modulation based on quadrature amplitude modulation.

[0278] In another possible design, the units in the device 1300 can be used to implement Figure 4 The corresponding process executed by the second source node in the method 400 shown. For example, the generation unit 1310 can be used to execute step 420 in method 400, and the transceiver unit 1320 can be used to execute steps 4302 and 440 in method 400.

[0279] For example, when the device 1300 is used to implement the function of the second source node in the method provided in the embodiments of this application, the generation unit 1310 can be used to generate a second modulation symbol, which includes symbols mapped on a second constellation diagram, wherein there is no more than one constellation point in each quadrant of the second constellation diagram, and the transmission power of the second modulation symbol is determined according to the transmission power of the first modulation symbol. The transceiver unit 1320 can be used to send the second modulation symbol to the relay node.

[0280] Optionally, the transceiver unit 1320 can also be used to receive second channel information, which is used to indicate the amplitude and phase of the first channel; or the amplitude ratio and phase difference between the second channel and the first channel; wherein the first channel is the channel between the first source node and the relay node, and the second channel is the channel between the second source node and the relay node.

[0281] Optionally, the transceiver unit 1320 can also be used to send a second request to the relay node, the second request being used to request the second channel information.

[0282] Optionally, the second modulation symbol is obtained by modulation based on quadrature phase shift keying modulation or binary phase shift keying modulation.

[0283] Optionally, the phase of the second modulation symbol is determined by the phase difference between the second channel and the first channel, wherein the first channel is the channel between the first source node and the relay node, and the second channel is the channel between the second source node and the relay node.

[0284] Optionally, the second modulation symbol is based on quadrature phase shift keying modulation, and the phase θ of the second modulation symbol S2 Phase difference Δθ Integer multiples of.

[0285] Optionally, the second modulation symbol is based on binary phase shift keying modulation, and the phase θ of the second modulation symbol S2 Phase difference Δθ An odd multiple of.

[0286] It should be understood that the division of units in the embodiments of this application is illustrative and only represents a logical functional division. In actual implementation, there may be other division methods. Furthermore, the functional units in the various embodiments of this application can be integrated into a single processor, exist as separate physical units, or be integrated into one unit by two or more units. The integrated units described above can be implemented in hardware or as software functional units.

[0287] Figure 14This is another schematic block diagram of the communication device provided in this application embodiment. The communication device 1400 can be a chip system. In this application embodiment, the chip system can be composed of chips, or it can include chips and other discrete devices.

[0288] like Figure 14 As shown, the device 1400 may include at least one processor 1410.

[0289] In one possible design, at least one processor 1410 may be used to implement the function of a relay node in the method provided in the embodiments of this application.

[0290] For example, when the device 1400 is used to implement the function of a relay node in the method provided in the embodiments of this application, the processor 1410 can be used to receive a first signal, which includes a first modulation symbol from a first source node and a second modulation symbol from a second source node; wherein, the first modulation symbol includes a symbol mapped on a first constellation diagram, in which there are multiple constellation points in the same quadrant of the first constellation diagram, and the minimum distance between two adjacent constellation points in the same quadrant is less than 2k, where k is a constellation mapping normalization factor; the second modulation symbol includes a symbol mapped on a second constellation diagram, in which there is no more than one constellation point in each quadrant of the second constellation diagram, and the transmission power of the second modulation symbol is determined according to the transmission power of the first modulation symbol; and the first signal is forwarded. See the detailed description in the method examples for further details, which will not be repeated here.

[0291] 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 this application.

[0292] For example, when the device 1400 is used to implement the function of the first source node or the second source node in the method provided in the embodiments of this application, the processor 1410 can be used to generate a first modulation symbol, which includes a symbol mapped on a first constellation map. The first constellation map contains multiple constellation points in the same quadrant, and the minimum distance between two adjacent constellation points in the same quadrant is less than 2k, where k is a constellation mapping normalization factor; and transmit the first modulation symbol to a relay node. Alternatively, it can be used to generate a second modulation symbol, which includes a symbol mapped on a second constellation map. The second constellation map contains no more than one constellation point in each quadrant, and the transmission power of the second modulation symbol is determined based on the transmission power of the first modulation symbol; and transmit the second modulation symbol to a relay node. See the detailed description in the method examples for further details, which will not be repeated here.

[0293] The device 1400 may further include at least one memory 1420 for storing program instructions and / or data. The memory 1420 is coupled to the processor 1410. The coupling in this embodiment is an indirect coupling or communication connection between devices, units, or modules, and may be electrical, mechanical, or other forms, for information exchange between devices, units, or modules. The processor 1410 may operate in conjunction with the memory 1420. The processor 1410 may execute program instructions stored in the memory 1420. At least one of the at least one memory may be included in the processor.

[0294] The device 1400 may further include a communication interface 1430 for communicating with other devices via a transmission medium, thereby enabling the device 1400 to communicate with other devices. For example, when the device 1400 is used to implement the function of a relay node in the method provided in this application embodiment, the other device may be a first source node or a second source node; when the device 1400 is used to implement the function of a first source node or a second source node in the method provided in this application embodiment, the other device may be a relay node. The communication interface 1430 may be, for example, a transceiver, an interface, a bus, a circuit, or a device capable of transmitting and receiving functions. The processor 1410 may utilize the communication interface 1430 to transmit and receive data and / or information, and to implement... Figure 4 The method executed by the relay node, the first source node, or the second source node in the corresponding embodiment.

[0295] This application embodiment does not limit the specific connection medium between the processor 1410, memory 1420, and communication interface 1430. This application embodiment... Figure 14 The processor 1410, memory 1420, and communication interface 1430 are connected via bus 1440. Bus 1440... Figure 14 The connections between other components are shown in thick lines only and are not intended to be limiting. This bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, Figure 14 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0296] It should be understood that the processor in this application can be an integrated circuit chip with signal processing capabilities. In implementation, the steps of the above method embodiments can be completed by the integrated logic circuits in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in memory, and the processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the above method.

[0297] It should also be understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0298] This application also provides a computer program product comprising: a computer program (also referred to as code or instructions), which, when executed, causes a computer to perform... Figure 4 The methods executed by the first source node, the second source node, or the relay node in the illustrated embodiments.

[0299] This application also provides a computer-readable storage medium storing a computer program (also referred to as code or instructions). When the computer program is executed, it causes the computer to perform... Figure 4 The methods executed by the first source node, the second source node, or the relay node in the illustrated embodiments.

[0300] The terms “unit”, “module”, etc., used in this specification may be used to refer to computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution.

[0301] Those skilled in the art will recognize that the various illustrative logical blocks and steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application. In the several embodiments provided in this application, it should be understood that the disclosed apparatus, devices, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for example, the division of units is merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the shown or discussed mutual couplings or direct couplings or communication connections may be through some interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0302] The unit described as a separate component may or may not be physically separate. The component shown as a unit may or may not be a physical unit; that is, it may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0303] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0304] In the above embodiments, the functions of each functional unit can be implemented entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. This computer program product includes one or more computer instructions (programs). When the computer program instructions (programs) are loaded and executed on a computer, all or part of the flow or function described in the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital video discs (DVDs)), or semiconductor media (e.g., solid-state disks (SSDs)).

[0305] If this function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0306] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication method, characterized in that, include: The relay node receives a first signal, the first signal including a first modulation symbol from a first source node and a second modulation symbol from a second source node; wherein, The first modulation symbol includes a symbol mapped on the first constellation diagram. There are multiple constellation points in the same quadrant of the first constellation diagram, and the minimum distance between two adjacent constellation points in the same quadrant is (2-2c)k, where k is the constellation mapping normalization factor, 0 < c < 1. The second modulation symbol includes a symbol mapped on a second constellation diagram, wherein there is no more than one constellation point in each quadrant of the second constellation diagram, and the transmission power of the second modulation symbol is determined based on the transmission power of the first modulation symbol; The relay node forwards the first signal.

2. The method as described in claim 1, characterized in that, The method further includes: The relay node sends first channel information to the first source node. The first channel information is used to indicate the amplitude 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. Wherein, the first channel is the channel between the first source node and the relay node, and the second channel is the channel between the second source node and the relay node.

3. The method as described in claim 2, characterized in that, The method further includes: The relay node receives a first request from the first source node, the first request being used to request the first channel information.

4. The method according to any one of claims 1 to 3, characterized in that, The method further includes: The relay node sends second channel information to the second source node. The second channel information is used to indicate the amplitude and phase of the first channel; or, the amplitude ratio and phase difference between the second channel and the first channel. Wherein, the first channel is the channel between the first source node and the relay node, and the second channel is the channel between the second source node and the relay node.

5. The method as described in claim 4, characterized in that, The method further includes: The relay node receives a second request from the second source node, the second request being used to request the second channel information.

6. A communication method, characterized in that, include: The first source node generates the first modulation symbol, which includes a symbol mapped on the first constellation diagram. There are multiple constellation points in the same quadrant of the first constellation diagram, and the minimum distance between two adjacent constellation points in the same quadrant is (2-2c)k, where k is the constellation mapping normalization factor, 0 < c < 1. The first source node sends the first modulation symbol to the relay node.

7. The method as described in claim 6, characterized in that, The method further includes: The first source node receives first channel information, which is used to indicate the amplitude 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. Wherein, the first channel is the channel between the first source node and the relay node, and the second channel is the channel between the second source node and the relay node.

8. The method as described in claim 7, characterized in that, The method further includes: The first source node sends a first request to the relay node, the first request being used to request the first channel information.

9. A communication method, characterized in that, include: The second source node generates a second modulation symbol, which includes a symbol mapped on a second constellation diagram. In the second constellation diagram, there is no more than one constellation point in each quadrant. The transmission power of the second modulation symbol is determined based on the transmission power of the first modulation symbol. The second source node sends the second modulation symbol to the relay node.

10. The method as described in claim 9, characterized in that, The method further includes: The second source node receives second channel information, which is used to indicate the amplitude and phase of the first channel; or, the amplitude ratio and phase difference between the second channel and the first channel. Wherein, the first channel is the channel between the first source node and the relay node, and the second channel is the channel between the second source node and the relay node.

11. The method as described in claim 10, characterized in that, The method further includes: The second source node sends a second request to the relay node, the second request being used to request the second channel information.

12. The method according to any one of claims 1 to 3, 5 to 8, characterized in that, 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 is such that the difference between the target bit error rate and 0.5 is no greater than Q(N) / 2, and Q(N) is the right-tail function of the 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 and the second modulation symbol, and the amplitude of the first channel and the first modulation symbol.

13. The method as described in claim 12, characterized in that, The method for determining parameter c is related to the modulation method of the first modulation symbol.

14. The method according to any one of claims 1 to 3, 5 to 8, and 13, characterized in that, The bit sequence corresponding to each constellation point in the first constellation diagram is obtained based on non-Gray code encoding.

15. The method as described in claim 14, characterized in that, The correspondence between multiple constellation points and bit sequences in the first constellation diagram is determined based on one of a variety of predefined encoding methods; The bit sequence includes four bits. In each of the multiple encoding methods, 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. In any two of the multiple encoding methods, the order of the bits corresponding to multiple constellation points on the I-axis is different, and / or the order of the bits corresponding to multiple constellation points on the Q-axis is different.

16. The method according to any one of claims 1 to 3, 5 to 11, 13, and 15, characterized in that, The first modulation symbol is obtained by modulation based on quadrature amplitude modulation.

17. The method according to any one of claims 1 to 3, 5, 9 to 11, characterized in that, The second modulation symbol is obtained by modulation based on quadrature phase shift keying modulation or binary phase shift keying modulation.

18. The method according to any one of claims 1 to 3, 5, and 9 to 11, characterized in that, The phase of the second modulation symbol is determined by the phase difference between the second channel and the first channel, where the first channel is the channel between the first source node and the relay node, and the second channel is the channel between the second source node and the relay node.

19. The method as described in claim 18, characterized in that, The second modulation symbol is based on quadrature phase shift keying modulation, and the phase θ of the second modulation symbol S2 The phase difference between the phase difference Δθ and the phase difference Integer multiples of; or, The second modulation symbol is based on binary phase shift keying modulation, and the phase θ of the second modulation symbol S2 The phase difference between the phase difference and the phase difference An odd multiple of.

20. A communication device, characterized in that, include: A receiving unit is configured to receive a first signal, the first signal including a first modulation symbol from a first source node and a second modulation symbol from a second source node; wherein, the first modulation symbol includes a symbol mapped on a first constellation diagram, the first constellation diagram having multiple constellation points in the same quadrant, and the minimum distance between two adjacent constellation points in the same quadrant being (2-2c)k, where k is a constellation mapping normalization factor, 0 < c < 1; the second modulation symbol includes a symbol mapped on a second constellation diagram, the second constellation diagram having no more than one constellation point in each quadrant, and the transmission power of the second modulation symbol being determined based on the transmission power of the first modulation symbol; A processing unit is used to forward the first signal.

21. A communication device, characterized in that, include: The generation unit is used to generate a first modulation symbol, which includes a symbol mapped on a first constellation diagram. There are multiple constellation points in the same quadrant of the first constellation diagram, and the minimum distance between two adjacent constellation points in the same quadrant is (2-2c)k, where k is the constellation mapping normalization factor, 0 < c < 1. Transceiver unit, used to send the first modulation symbol to the relay node; or, The generation unit is used to generate a second modulation symbol, which includes a symbol mapped on a second constellation diagram. The second constellation diagram contains no more than one constellation point in each quadrant. The transmission power of the second modulation symbol is determined based on the transmission power of the first modulation symbol. The transceiver unit is used to send the second modulation symbol to the relay node.

22. A communication device, characterized in that, Includes a processor for executing program code to implement the method as described in any one of claims 1 to 19.

23. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it causes the computer to perform the method as described in any one of claims 1 to 19.

24. A computer program product, characterized in that, Includes a computer program that, when run, causes a computer to perform the method as described in any one of claims 1 to 19.

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