CN-116488703-B - Unmanned aerial vehicle relay system short packet communication method based on NOMA technology

CN116488703BCN 116488703 BCN116488703 BCN 116488703BCN-116488703-B

Abstract

The disclosure provides an unmanned aerial vehicle relay system short packet communication method based on NOMA technology. The method comprises the steps of establishing a system model of an unmanned aerial vehicle relay system, wherein the system model comprises a control end, an unmanned aerial vehicle and a plurality of target users, performing short packet communication transmission among the control end, the unmanned aerial vehicle and the plurality of target users based on a NOMA technology, and jointly optimizing the total length of a data packet in the short packet communication transmission, the flight position of the unmanned aerial vehicle and the power distribution of the unmanned aerial vehicle based on the system model to obtain the minimized effective packet error rate of the target users. The method provided by the disclosure can effectively reduce the communication time delay of short packet transmission in the unmanned aerial vehicle relay system and the effective packet error rate of the target user.

Inventors

HU HANG
HAN HUIZHU
HUANG YANGCHAO
KANG QIAOYAN
SI JIANGBO
Zhao Senhao
XIE TIECHENG
PAN YU

Assignees

中国人民解放军空军工程大学

Dates

Publication Date: 20260505
Application Date: 20230309

Claims (8)

1. The unmanned aerial vehicle relay system short packet communication method based on NOMA technology is characterized by comprising the following steps: Establishing a system model of an unmanned aerial vehicle relay system, wherein the system model comprises a control end, an unmanned aerial vehicle and a plurality of target users, and the control end, the unmanned aerial vehicle and the plurality of target users carry out short packet communication transmission based on a NOMA technology; Based on the system model, the total length of the data packet, the flight position of the unmanned aerial vehicle and the power distribution of the unmanned aerial vehicle in the short packet communication transmission are jointly optimized to obtain the minimum effective packet error rate of the target user, and the method comprises the following steps of decomposing the joint optimization into three sub problems, namely: a first sub-problem of optimizing the total length of the data packet given the unmanned aerial vehicle flight location and the unmanned aerial vehicle allocated power; a second sub-problem of optimizing the unmanned aerial vehicle flight position given the total length of the data packets and the unmanned aerial vehicle allocated power; a third sub-problem of optimizing the drone power allocation given the total length of the data packets and the drone flight location; analyzing monotonicity and convexity of the objective function in the first sub-problem, the second sub-problem and the third sub-problem, respectively; Solving the minimized effective packet error rate of the target user by utilizing an overall iterative optimization algorithm in combination with an analysis result; wherein the jointly optimized expression comprises: (10) (10a) (10b) (10c) (10d) (10e) (10f) Wherein s.t. represents a constraint, i.e. "constrained to"; the length of a data packet from a control end to the unmanned aerial vehicle is represented; indicating the gain user data packet length; the packet length from the drone to the high channel gain user R1 is represented; The length of a data packet from the unmanned aerial vehicle to the low-channel gain user R2 is represented, M represents the total length of the data packet, Z represents a positive integer set, and P represents the maximum transmitting power of the unmanned aerial vehicle; Representing allocated power at high channel gain user R1; representing allocated power at low channel gain user R2; representing transmitted signals transmitted at high channel gain user R1 An effective packet error rate at the high channel gain user R1; A transmit signal representing the control terminal; representing a transmission signal transmitted by a control end to a high channel gain user R1; representing a transmission signal transmitted by a control end to a low channel gain user R2; Representing the flight position of the unmanned aerial vehicle; Representation of Is set to a threshold value of (2); The function of the object is represented by a function of the object, , ; Information quantity of data packets representing the unmanned aerial vehicle to the low channel gain user R2; Information quantity of data packets from a control end to the unmanned aerial vehicle is represented; the effective packet error rate from the control end to the unmanned aerial vehicle is represented; Representing a transmission signal transmitted by a control terminal to a low channel gain user R2 The effective packet error rate at the low channel gain user R2, min, represents minimization.
2. The short packet communication method of a unmanned aerial vehicle relay system based on NOMA technology according to claim 1, wherein in the step of establishing a system model of the unmanned aerial vehicle relay system, The control end and the target users are positioned on the ground, and the horizontal flying height of the unmanned aerial vehicle from the ground is H; The target users comprise high-channel gain users R1 and low-channel gain users R2, wherein the Gao Xindao gain users R1 are positioned at the maximum position of the channel gain in the coverage area of the unmanned aerial vehicle, and the low-channel gain users R2 are positioned at the minimum position of the channel gain in the coverage area of the unmanned aerial vehicle; the coordinates of the control end are , The Gao Xindao gain user R1 has the following coordinates The coordinates of the low-channel gain user R2 are as follows The information quantity of the data packet from the control end to the unmanned aerial vehicle is that Bit, the information amount of the data packet from the unmanned aerial vehicle to the Gao Xindao gain user R1 is that The information content of the data packet from the unmanned aerial vehicle to the low-channel gain user R2 is as follows The number of bits that can be used to determine, ; The expression of the total length M of the data packet in the short packet communication transmission comprises: (1) wherein M represents the total length of the data packet; b represents the bandwidth of the system model; the length of a data packet from a control end to the unmanned aerial vehicle is represented; the packet length from the drone to the high channel gain user R1 is represented; the packet length from the drone to the low channel gain user R2; The transmission channel of the short packet communication transmission is subject to free space path loss, the channel gain of the transmission channel The expression of (2) includes: (2) Wherein, the H represents the horizontal flight altitude of the unmanned aerial vehicle; Representing the abscissa; A transmit signal representing the control terminal; Representing the channel gain from the control end to the unmanned aerial vehicle; Representing the channel gain of the drone to the high channel gain user R1, Representing the channel gain of the drone to the low channel gain user R2, and ; LoS links are arranged among the control end, the unmanned aerial vehicle and the target users, and the packet error rate of the LoS links The expression of (2) includes: (3) Wherein, the A right tail function representing a standard normal distribution; Representing the signal-to-noise ratio; representing the length of the data packet; information quantity representing data packet; , Representing the dispersion of the transmission channel, Any one of the LoS links satisfies 。
3. The unmanned aerial vehicle relay system short packet communication method based on the NOMA technology according to claim 2, wherein, The Gao Xindao gains the received signal at the user R1 The expression of (2) includes: (4) Wherein, the Representing a transmission signal transmitted by a control end to a high channel gain user R1; representing a transmission signal transmitted by a control end to a low channel gain user R2; Representing allocated power at high channel gain user R1; representing allocated power at low channel gain user R2; representing normalized noise power at high channel gain user R1; The control end transmits a transmitting signal to the low channel gain user R2 Signal to interference plus noise ratio at Gao Xindao gain user R1 The expression of (2) includes: (5) The control end transmits a transmitting signal to the Gao Xindao gain user R1 The expression of the effective packet error rate at Gao Xindao gain user R1 includes: (6) Wherein, the Representing transmitted signals transmitted at high channel gain user R1 An effective packet error rate at the high channel gain user R1; Representation and representation The corresponding effective error probability; Representing a transmission signal transmitted by a control terminal to a high channel gain user R1 The effective error probability corresponding to the effective packet error rate at the Gao Xindao gain user R1; Representation of The corresponding effective error probability; Representing the signal to noise ratio at the high channel gain user R1.
4. The unmanned aerial vehicle relay system short packet communication method based on the NOMA technology according to claim 3, wherein, The received signal at the low channel gain user R2 The expression of (2) includes: (7) Wherein, the Representing normalized noise power at low channel gain user R2; The control end transmits a transmitting signal to the low channel gain user R2 Signal to interference plus noise ratio at the low channel gain user R2 The expression of (2) includes: (8) The control end transmits signals to the low channel gain user R2 The expression of the effective packet error rate at the low channel gain user R2 includes: (9) Wherein, the Representing transmitted signals transmitted at low channel gain user R2 An effective packet error rate at the low channel gain user R2; Representing the signal-to-noise ratio at the low channel gain user R2; the packet length from the drone to the low channel gain user R2; The amount of information of the data packet representing the low channel gain user R2.
5. The NOMA technology-based unmanned aerial vehicle relay system short packet communication method according to claim 1, wherein the expression of the first sub-problem includes: (11) (11a) (10b) (10f) wherein the objective function Comprising two concave functions.
6. The NOMA technology-based unmanned aerial vehicle relay system short packet communication method according to claim 1, wherein the expression of the second sub-problem includes: (12) (10c) (10d) wherein the objective function Comprising two concave functions.
7. The NOMA technology-based unmanned aerial vehicle relay system short packet communication method according to claim 1, wherein the expression of the third sub-problem includes: (13) (10d) (10e) (10f) wherein the objective function Comprising two concave functions.
8. The unmanned aerial vehicle relay system short packet communication method based on the NOMA technology of claim 5, wherein, The integral iterative optimization algorithm comprises an alternate direction multiplier algorithm and an optimal solution algorithm; The expression of the optimal solution of the first sub-problem includes: (14) Wherein, the ; An optimal solution of an objective function representing the first sub-problem; Representing a infinitesimal; carrying out iterative solution on the first sub-problem by using the alternating direction multiplier algorithm to obtain the optimal total length of the data packet when the target user has the minimized effective packet error rate; Carrying out iterative solution on the second sub-problem by utilizing the optimal solution algorithm to obtain an optimal unmanned aerial vehicle flight position when the target user has the minimized effective packet error rate; and carrying out iterative solution on the third sub-problem by using the optimal solution algorithm to obtain optimal unmanned aerial vehicle power distribution when the target user has the minimized effective packet error rate.

Description

Unmanned aerial vehicle relay system short packet communication method based on NOMA technology Technical Field The disclosure relates to the technical field of unmanned aerial vehicle communication, in particular to an unmanned aerial vehicle relay system short packet communication method based on NOMA technology. Background Unmanned AERIAL VEHICLE, UAV communication is receiving attention due to its high channel gain and flexible deployment. The unmanned aerial vehicle flight height is higher, can realize the stadia communication to can effectively reduce shadow effect and signal fading. If there is no direct communication link between the two ground nodes, a communication scheme using the drone as a mobile relay may be employed. Ultra-Reliable and Low-latency communication (URLLC) is one of the three major leg applications of 5G mobile communication networks. In URLLC, the fragrance formula at infinite packet length is no longer used because the packet error rate (Packet Error Rate, PER) at the receiver cannot be ignored. Thus, low latency transmission of the drone communication system may be ensured by short packet communication within a limited packet. The Non-orthogonal multiple access (NOMA) technology can ensure fairness among users and flexibility of scheduling, thereby improving spectrum efficiency of a system and increasing the number of connections of devices. To analyze the performance of NOMA, successive interference cancellation (Successive Interference Cancellation, SIC) is often used to fully cancel co-channel interference and to enable efficient decoding of the desired signal. The advantages of NOMA technology are widely used in various wireless communications, such as Physical Layer Security (PLS), full duplex transmission and broadcast channels, etc. However, in short packet communications, NOMA has a role in reducing transmission delay, and the effect of limited packet length on NOMA performance characteristics has been studied less. Accordingly, there is a need to provide a new solution to ameliorate one or more of the problems presented in the above solutions. It should be noted that the information disclosed in the above background section is only for enhancing understanding of the background of the present disclosure and thus may include information that does not constitute prior art known to those of ordinary skill in the art. Disclosure of Invention The embodiment of the disclosure aims to provide a short packet communication method of an unmanned aerial vehicle relay system based on NOMA technology, which can effectively reduce communication delay of short packet transmission in the unmanned aerial vehicle relay system and effective packet error rate of a target user. The method comprises the following steps: Establishing a system model of an unmanned aerial vehicle relay system, wherein the system model comprises a control end, an unmanned aerial vehicle and a plurality of target users, and the control end, the unmanned aerial vehicle and the plurality of target users carry out short packet communication transmission based on a NOMA technology; Based on the system model, the total length of the data packet, the flight position of the unmanned aerial vehicle and the power distribution of the unmanned aerial vehicle in the short packet communication transmission are jointly optimized, and the minimum effective packet error rate of the target user is obtained. In an exemplary embodiment of the present disclosure, in the step of modeling the system of the unmanned aerial vehicle relay system, The control end and the target users are positioned on the ground, and the horizontal flying height of the unmanned aerial vehicle from the ground is H; The target users comprise high-channel gain users R1 and low-channel gain users R2, wherein the Gao Xindao gain users R1 are positioned at the maximum position of the channel gain in the coverage area of the unmanned aerial vehicle, and the low-channel gain users R2 are positioned at the minimum position of the channel gain in the coverage area of the unmanned aerial vehicle; The coordinates of the control end are (D 0,0),D0 =0), the coordinates of the Gao Xindao gain user R1 are (D 1, 0), the coordinates of the low-channel gain user R2 are (D 2, 0), the information amount of the data packet from the control end to the unmanned aerial vehicle is L 0 bits, the information amount of the data packet from the unmanned aerial vehicle to the Gao Xindao gain user R1 is L 1 bits, the information amount of the data packet from the unmanned aerial vehicle to the low-channel gain user R2 is L 2 bits, and L 0＝L1+L2; the expression of the total length M of the data packet in the short packet communication transmission comprises: m1+m2+m0≤B·Tmax=M (1) Wherein M represents the total length of the data packet, T max represents the transmission time of the whole short packet communication, B represents the bandwidth of a system model, M 0 represents the data pa