Low-power-consumption equipment access method based on movable clamping antenna

Abstract

The invention provides a low-power-consumption equipment access method based on a movable clamping antenna, and relates to the technical field of wireless communication, and the method comprises the steps: constructing a communication system comprising a base station and K low-power-consumption equipment, uniformly arranging a plurality of transmitting clamping units on a transmitting waveguide of the base station, and uniformly arranging a plurality of receiving clamping units on a receiving waveguide of the base station; based on the communication system, constructing an optimization problem which maximizes the minimum transmission rate of the low-power-consumption equipment; the position configuration of the clamping units is designed by using a two-stage strategy to solve the optimization problem, the two-stage strategy comprises macroscopic position configuration of the clamping units aiming at large-scale path loss and fine adjustment of the macroscopic positions of the clamping units aiming at small-scale phase shift influence, and the clamping units refer to a sending clamping unit and a receiving clamping unit. According to the invention, the flexibility of the clamping antenna in deployment can be improved, and the transmission performance of the time division multiple access system is improved.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a low-power device access method based on a movable clamping antenna. Background Technology

[0002] With the development of low-power technologies such as the Internet of Things (IoT), wireless sensor networks, and backscatter communication, a large number of low-power terminal devices need to access base stations to achieve multiple access communication. As the number of terminals continues to increase, the channel quality differences between different devices gradually widen. Some devices far from the base station may even be unable to complete information transmission due to poor transmission quality, thus limiting the overall system performance. To address this limitation, existing fixed antenna layouts lack flexibility and cannot adaptively improve link quality based on device distribution in low-power wireless communication scenarios, thereby restricting the transmission quality of low-power devices in multiple access scenarios.

[0003] Pinching-Antenna Systems (PASS), proposed in recent years, offer a new possibility for solving the aforementioned problems. This system, by mounting movable pinning units on a dielectric waveguide, allows for flexible adjustment of the pinning unit's position and reconstruction of new line-of-sight transmission links, effectively mitigating the severe path loss problem of traditional antennas in long-distance transmission and significantly improving channel quality. However, in low-power multiple access scenarios, how to leverage the deployment flexibility of pinning antennas and combine it with the distributed characteristics of low-power terminals to design a method that can significantly improve multiple access performance has become a pressing technical challenge. Summary of the Invention

[0004] The main objective of this invention is to propose a low-power device access method based on a movable clamping antenna, which can improve the deployment flexibility of the clamping antenna and enhance the transmission performance of the time division multiple access system.

[0005] This invention is achieved through the following technical solution: A low-power device access method based on a movable clamping antenna includes the following steps: Step S1: Construct a communication system including a base station and K low-power devices, with the base station's transmitting waveguides evenly distributed... Each transmitting clamping unit is evenly arranged on the receiving waveguide. One receiving clamping unit; Step S2: Based on the communication system, model the transmission channel from the transmitting waveguide feed point through the transmitting clamping unit to the low-power device, and the receiving channel from the low-power device through the receiving clamping unit to the receiving waveguide feed point, and then construct an optimization problem that maximizes the minimum transmission rate of the low-power device. Step S3: Use a two-stage strategy to design the position configuration of the clamping unit in order to solve the optimization problem. The two-stage strategy includes macroscopic position configuration of the clamping unit for large-scale path loss and fine-tuning of the macroscopic position of the clamping unit for small-scale phase shift effects. The clamping unit refers to the transmitting clamping unit and the receiving clamping unit.

[0006] Furthermore, in step S1, in the communication system, the K low-power devices are distributed along the xy dimension. In the plane, the position of the k-th low-power device is denoted as , and These are the x-axis and y-axis values ​​for the k-th low-power device, respectively.

[0007] Furthermore, in step S1, the base station uses two dielectric waveguides at a height d above the ground as the transmitting waveguide and the receiving waveguide, respectively, and the feed points of the transmitting waveguide and the receiving waveguide are respectively denoted as... and The positions of the transmitting clamping unit and the receiving clamping unit are respectively represented as follows: and The interval between two adjacent transmitting clamping units and two adjacent receiving clamping units is greater than the set minimum clamping unit interval. The low-power device receives the downlink signal from the transmitting waveguide and performs modulation and reflection to complete multi-device uplink data transmission based on the time division multiple access protocol. The number of transmitting clamping units and receiving clamping units is the same. .

[0008] Furthermore, in step S2, the transmission channel originating from the transmit waveguide feed point, passing through the transmit clamping unit m, and reaching the low-power device k is represented as follows: The receiving channel from the low-power device k to the receiving clamping unit m is represented as follows: ,in, Transmission path loss per unit distance in space, To transmit the wavelength of the signal carrier in a vacuum, To transmit the wavelength of the signal carrier in the waveguide, It is treated as a 2-norm.

[0009] Furthermore, in step S2, the optimization problem is expressed as: ,in, This represents the lower limit of the transmission rate for all low-power devices. The positions of each transmitting clamping unit on the transmitting waveguide. For the transmission rate of low-power device k, Assign transmission time slots to the k-th backscattering device. For the minimum clamping unit spacing, P represents the noise power of the ambient noise, and P represents the base station's transmit power.

[0010] Furthermore, in step S3, configuring the clamping unit positions to address large-scale path loss specifically involves ensuring that the phases of the received arrival signals from the feed point, after passing through each transmitting clamping unit, are consistent for each low-power device, as expressed in: Then the optimization problem is transformed into a second optimization problem. In this second optimization problem, the first and second constraints are relative to the auxiliary variables. If the problem is non-convex, then performing a first-order Taylor expansion on the non-convex constraints based on the Taylor expansion center transforms the second optimization problem into a convex third optimization problem. Solving this third optimization problem yields the macroscopic positions of each transmitting clamping unit, where... For the introduced auxiliary variables, For low-power devices With the sending clamping unit The center of the first-order Taylor expansion, .

[0011] Furthermore, in step S3, configuring the position of the clamping unit in response to the small-scale phase shift effect specifically involves: based on the macroscopic position of the transmitting clamping unit obtained above, obtaining the position range for fine-tuning the transmitting clamping unit, and selecting from this position space the position that maximizes the third optimization problem as the final position of the transmitting clamping unit.

[0012] Furthermore, in step S3, it is assumed that the current adjustment is in the nth round, and the position of the mth transmitting clamping unit in the (n-1)th round is known. Then, the approximate relationship between the carrier channel phase change of the low-power device k and the position change of the m-th transmitting clamping unit is expressed as: Considering the need to cover all phases during fine-tuning and to satisfy the minimum isolation factor between adjacent transmit clamping units, the position range for fine-tuning the m-th transmit clamping unit is obtained. Based on this location space, a discrete search method is used to obtain a location set with N discrete points, and the location that maximizes the third optimization problem is selected from this location set as the final location of the sending clamping unit.

[0013] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects: This invention first constructs a communication system comprising a base station and K low-power devices, with the base station's transmitting waveguides uniformly arranged... Each transmitting clamping unit is evenly arranged on the receiving waveguide. This paper proposes a receiving clamping unit. Based on the communication system, it models the transmission channel from the transmitting waveguide feed point through the transmitting clamping unit to the low-power device, and the receiving channel from the low-power device through the receiving clamping unit to the receiving waveguide feed point. This leads to an optimization problem that maximizes the minimum transmission rate of the low-power device. Finally, a two-stage strategy is used to design the position configuration of the clamping unit to solve this optimization problem. The two-stage strategy includes macroscopic position configuration of the clamping unit to address large-scale path loss and fine-tuning of the macroscopic position of the clamping unit to address small-scale phase shift effects. This enables flexible control of the transmission channel between the clamping antenna and the terminal device at both large and small scales, overcoming the shortcomings of traditional fixed antenna layouts in terms of scenario adaptability. The "two-stage optimization strategy" separates large-scale path loss from small-scale phase shift effects, simplifying the overall optimization problem and reducing computational complexity. It can improve the minimum transmission rate, system throughput, access fairness, energy efficiency, and spectrum utilization of low-power devices in time-division multiple access scenarios. It can also significantly improve the access performance of weak-channel devices, enhance system robustness, and adapt to dynamic environmental changes. Attached Figure Description

[0014] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] Figure 1 This is a flowchart of the present invention.

[0016] Figure 2 This is a schematic diagram of the communication system of the present invention.

[0017] Figure 3 This is a performance simulation comparison chart of the present invention and the traditional method.

[0018] Figure 4 This is another performance simulation comparison chart between the present invention and the traditional method. Detailed Implementation

[0019] The present invention will be further described below through specific embodiments.

[0020] like Figure 1 As shown, the low-power device access method based on a movable clamping antenna includes the following steps: Step S1: Construct a communication system including a base station and K low-power devices, with the base station's transmitting waveguides evenly distributed... Each transmitting clamping unit is evenly arranged on the receiving waveguide. One receiving clamping unit; like Figure 1 In the communication system shown, K low-power devices are distributed along the xy dimension. In the plane, the position of the k-th low-power device is denoted as The unit is meters. and These are the x-axis and y-axis values ​​for the k-th low-power device, respectively.

[0021] The base station uses two dielectric waveguides as the transmitting and receiving waveguides, respectively. The transmitted signal from the transmitting clamp unit on the transmitting waveguide powers the backscattering device and provides the carrier signal for the backscattering device's reflected transmission. The base station's transmit power is... Watt; a receiver clamping unit on the receiving waveguide, used to receive signals reflected by the backscattering device. In this embodiment, the number of transmitting clamping units is the same as the number of receiving clamping units, i.e. .

[0022] Both dielectric waveguides are at a height d above the ground. The positions of the transmitting clamping unit and the receiving clamping unit are respectively represented as... and The unit is meters, and the interval between two adjacent transmitting clamping units and two adjacent receiving clamping units is greater than the set minimum clamping unit interval. ,Right now , The feed points of the transmitting and receiving waveguides are respectively denoted as... and The wavelength of the transmitted signal carrier in a vacuum is meters, with a wavelength of in a dielectric waveguide meters, signal carrier frequency is hertz.

[0023] Low-power devices complete multi-device uplink data transmission based on a time-division multiple access protocol by receiving, modulating, and reflecting downlink signals from the transmitting waveguide. The allocated transmission time slot for the k-th low-power device is denoted as […]. and satisfy ,in The total system transmission time is in seconds. Optionally, this embodiment uses... The low-power devices are specifically backscattering devices.

[0024] Step S2: Based on the communication system, model the transmission channel from the transmitting waveguide feed point through the transmitting clamping unit to the low-power device, and the receiving channel from the low-power device through the receiving clamping unit to the receiving waveguide feed point, and then construct an optimization problem that maximizes the minimum transmission rate of the low-power device. The following description uses the transmitting clamping unit as an example to illustrate the position configuration. The position configuration process for the receiving unit is the same as that for the transmitting clamping unit.

[0025] For the aforementioned communication system, the free-space channel between the transmitting clamping unit and the backscattering device is represented as follows: ,in, For L2 norm processing, , Let c be the transmission path loss per unit distance in space, and c be the speed of light in free space. Let be the base of the natural logarithm of the complex field.

[0026] Considering that all transmitting clamping units are arranged along the same dielectric waveguide, the signal transmitted through the dielectric waveguide and from the clamping unit will have a phase shift due to transmission. Taking into account this phase shift, the transmission channel from the transmitting waveguide feed point, through the transmitting clamping unit m to the low-power device k is represented as follows: ; Similarly, the receive channel from low-power device k to receiver clamping unit m is represented as follows: .

[0027] Therefore, after modulation and reflection by the backscattering device, the signal relative to the receiver feed point... In other words, the received signal from the backscattering device is represented as Therefore, the transmission rate of the backscattering device k is... Where s is the data carried by the dielectric waveguide transmission carrier. Data modulated by a backscattering device.

[0028] By jointly optimizing the positions of the clamping units on the transmitting and receiving waveguides along the x-axis, and combining this with a time-division multiple access protocol, a solution is achieved for the problem of maximizing the minimum transmission rate of backscattering devices. The positions of each transmitting clamping unit on the transmitting waveguide are denoted as follows: Therefore, the optimization problem can be expressed as: ,in, This represents the lower limit of the transmission rate for all low-power devices. The noise power is the ambient noise in the signal received by the receiving antenna.

[0029] Step S3: Use a two-stage strategy to design the position configuration of the clamping unit in order to solve the optimization problem. The two-stage strategy includes macroscopic position configuration of the clamping unit for large-scale path loss and fine-tuning of the macroscopic position of the clamping unit for small-scale phase shift influence. The clamping unit refers to the transmitting clamping unit and the receiving clamping unit. In the optimization problem described above, the first constraint The optimization target is guaranteed to be the lower limit of the transmission rate of all devices. The latter two constraints restrict the position of the transmitting clamping unit. Since adjusting the position of each transmitting clamping unit will simultaneously cause both large-scale path loss and small-scale phase shift to the transmission channel, and the transmission rate function is a nonlinear combination of the channel gain between each transmitting clamping unit and the backscattering device, the first constraint in the above optimization problem is a strongly nonconvex constraint, which is difficult to solve analytically directly. Therefore, a two-stage strategy is adopted for the solution.

[0030] This step decouples the channel between the base station and the backscattering device, dividing it into a large-scale path loss component and a small-scale phase shift effect component. The large-scale path loss is primarily determined by the transmission distance between the clamping unit and the terminal, reflecting the signal strength attenuation with distance; the small-scale phase shift effect is manifested as the phase change introduced by wireless and dielectric waveguide transmission.

[0031] Minor adjustments to the position of the clamping unit cause periodic, small-scale phase changes, but their amplitude is much smaller than the transmission distance between the clamping unit and the low-power device. Based on this characteristic, this embodiment proposes a two-stage optimization strategy: the first stage configures the macroscopic position of the clamping unit to address large-scale path loss; the second stage addresses the impact of small-scale phase shift by fine-tuning the clamping unit position to achieve a refined configuration. The two stages of optimization are independent but work together to effectively improve the overall system performance.

[0032] When dealing with large-scale path loss, we first disregard the effects of small-scale losses, assuming perfect elimination of small-scale losses. In this case, the specific configuration of the clamping unit positions is as follows: For each low-power device, the received signals from the feed point, after passing through each transmitting clamping unit, are in phase, denoted as: Then the transmission channel from the feed point through the clamping unit to the device can be re-represented as Then the transmission rate of the backscattering device k is updated to The first constraint of the optimization problem is addressed in conjunction with this transmission rate. To facilitate the use of convex optimization techniques to handle this first constraint, auxiliary variables are introduced. It satisfies the constraints Based on this auxiliary variable, the first constraint can be relaxed: ,in, Then the above optimization problem is transformed into a second optimization problem. In this second optimization problem, the first and second constraints are relative to the auxiliary variables. For non-convex constraints, a continuous convex approximation technique is used. Specifically, based on local points... Performing a first-order Taylor expansion on the non-convex constraint yields an approximate convex constraint form: , .

[0033] Based on this convex constraint form, the aforementioned second optimization problem can be transformed into a convex third optimization problem. Solving this third optimization problem yields the macroscopic position (approximate position) of each transmitting clamping unit, where... For low-power devices With the sending clamping unit The expansion center of the first-order Taylor expansion.

[0034] The above provides an approximate location of the transmitting clamping units, but the assumption that "the phase of the signals transmitted by each clamping unit arrives at each device is consistent" is too idealistic. To mitigate the impact of inconsistent arrival signal phases on the transmission rate, based on the macroscopic location of the transmitting clamping units, fine-tuning of the transmitting clamping unit position configuration is needed to account for small-scale phase shift effects.

[0035] To reduce the complexity of the fine-tuning design of the clamping unit positions, it is necessary to determine the minimum fine-tuning range of each transmitting clamping unit to reduce computational overhead. In this embodiment, an iterative method is adopted to configure the position of each transmitting clamping unit through a discrete search approach. Specifically, based on the macroscopic position of the transmitting clamping unit obtained above, the position range for fine-tuning the transmitting clamping unit is obtained, and the position that maximizes the third optimization problem is selected from this position space as the final position of the transmitting clamping unit.

[0036] Assume we are currently performing the nth round of fine-tuning, and the position of the mth transmitting clamping unit in the (n-1)th round is known. Then, the approximate relationship between the carrier channel phase change of the low-power device k and the position change of the m-th transmitting clamping unit is expressed as: , This is the position of the sending clamping unit after this round of fine-tuning.

[0037] By taking values This ensures that all phase conditions are covered when fine-tuning the position of the transmitting clamping unit, i.e. Combining the above approximate formula, we can derive the position range for fine-tuning the clamping unit relative to the target backscattering device k, under the condition of covering the entire phase change range. .

[0038] Considering the need to cover all phases during fine-tuning and to satisfy the minimum isolation factor between adjacent transmit clamping units, the position range for fine-tuning the m-th transmit clamping unit can be obtained. Based on this location space, a discrete search method is used to obtain a location set with N discrete points, and the location that maximizes the third optimization problem is selected from this location set as the final location of the sending clamping unit.

[0039] When the gain improvement in the current iteration is lower than a preset threshold Or reach the set maximum number of iterations. At this point, the iteration process terminates, thus determining the final result of fine-tuning the position configuration of the transmitting clamping unit to address the effects of small-scale phase shifts.

[0040] The parameter configurations in this embodiment are shown in Table 1.

[0041] Table 1 Figure 3 and Figure 4 In traditional methods, only the beamforming parameters are optimized, while the antenna array elements (PAs) are uniformly arranged at the feed point with half-wavelength spacing. Antenna fixing methods involve PAs being uniformly distributed along the waveguide, with their positions pre-arranged at equal intervals within a given range. It does not participate in dynamic position optimization.

[0042] from Figure 3 and Figure 4 As can be seen, the minimum transmission rate of the present invention (the proposed method) is the largest compared to the two comparative methods, when the number of clamping units or the number of devices are used as a lateral reference, that is, the present invention has superior performance.

[0043] In this invention, the terms "first," "second," and "third," etc., are used only to distinguish similar objects and are not necessarily used to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. The use of terms such as "upper," "lower," "left," "right," "front," and "rear" to indicate orientation or positional relationships is based on the orientation or positional relationships shown in the accompanying drawings and is only for the convenience of describing the invention, not to indicate or imply that the device referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the scope of protection of this invention. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0044] Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0045] The above are merely specific embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be considered as infringing upon the protection scope of the present invention.

Claims

1. A low-power device access method based on a movable clamping antenna, characterized in that: Includes the following steps: Step S1: Construct a communication system including a base station and K low-power devices, with the base station's transmitting waveguides evenly distributed... Each transmitting clamping unit is evenly arranged on the receiving waveguide. One receiving clamping unit; Step S2: Based on the communication system, model the transmission channel from the transmitting waveguide feed point through the transmitting clamping unit to the low-power device, and the receiving channel from the low-power device through the receiving clamping unit to the receiving waveguide feed point, and then construct an optimization problem that maximizes the minimum transmission rate of the low-power device. Step S3: Use a two-stage strategy to design the position configuration of the clamping unit in order to solve the optimization problem. The two-stage strategy includes macroscopic position configuration of the clamping unit for large-scale path loss and fine-tuning of the macroscopic position of the clamping unit for small-scale phase shift effects. The clamping unit refers to the transmitting clamping unit and the receiving clamping unit.

2. The low-power device access method based on a movable clamping antenna according to claim 1, characterized in that: In step S1, in the communication system, K low-power devices are distributed along the xy dimension. In the plane, the position of the k-th low-power device is denoted as , and These are the x-axis and y-axis values ​​for the k-th low-power device, respectively.

3. The low-power device access method based on a movable clamping antenna according to claim 2, characterized in that: In step S1, the base station uses two dielectric waveguides at a height d above the ground as the transmitting waveguide and the receiving waveguide, respectively. The feed points of the transmitting waveguide and the receiving waveguide are respectively denoted as... and The positions of the transmitting clamping unit and the receiving clamping unit are respectively represented as follows: and The interval between two adjacent transmitting clamping units and two adjacent receiving clamping units is greater than the set minimum clamping unit interval. The low-power device receives the downlink signal from the transmitting waveguide and performs modulation and reflection to complete multi-device uplink data transmission based on the time division multiple access protocol. The number of transmitting clamping units and receiving clamping units is the same. .

4. The low-power device access method based on a movable clamping antenna according to claim 3, characterized in that: In step S2, the transmission channel starting from the transmit waveguide feed point, passing through the transmit clamping unit m to the low-power device k is represented as follows: The receiving channel from the low-power device k to the receiving clamping unit m is represented as follows: ,in, Transmission path loss per unit distance in space, To transmit the wavelength of the signal carrier in a vacuum, To transmit the wavelength of the signal carrier in the waveguide, It is treated as a 2-norm.

5. A low-power device access method based on a movable clamping antenna according to claim 4, characterized in that: In step S2, the optimization problem is expressed as: ,in, This represents the lower limit of the transmission rate for all low-power devices. The positions of each transmitting clamping unit on the transmitting waveguide. For the transmission rate of low-power device k, Assign transmission time slots to the k-th backscattering device. For the minimum clamping unit spacing, P represents the noise power of the ambient noise, and P represents the base station's transmit power.

6. A low-power device access method based on a movable clamping antenna according to claim 5, characterized in that: In step S3, configuring the clamping unit positions to address large-scale path loss specifically involves ensuring that the received arrival signals from the feed point, after passing through each transmitting clamping unit, are in phase for each low-power device, as expressed in: Then the optimization problem is transformed into a second optimization problem. In this second optimization problem, the first and second constraints are relative to the auxiliary variables. If the problem is non-convex, then performing a first-order Taylor expansion on the non-convex constraints based on the Taylor expansion center transforms the second optimization problem into a convex third optimization problem. Solving this third optimization problem yields the macroscopic positions of each transmitting clamping unit, where... For the introduced auxiliary variables, For low-power devices With the sending clamping unit The center of the first-order Taylor expansion, .

7. A low-power device access method based on a movable clamping antenna according to claim 6, characterized in that: In step S3, the specific method for configuring the position of the clamping unit in response to the small-scale phase shift effect is as follows: based on the macroscopic position of the transmitting clamping unit obtained above, the position range for fine-tuning the transmitting clamping unit is obtained, and the position that maximizes the third optimization problem is selected from this position space as the final position of the transmitting clamping unit.

8. A low-power device access method based on a movable clamping antenna according to claim 7, characterized in that: In step S3, it is assumed that the current step is the nth round of fine-tuning, and the position of the mth transmitting clamping unit in the (n-1)th round is known. Then, the approximate relationship between the carrier channel phase change of the low-power device k and the position change of the m-th transmitting clamping unit is expressed as: Considering the need to cover all phases during fine-tuning and to satisfy the minimum isolation factor between adjacent transmit clamping units, the position range for fine-tuning the m-th transmit clamping unit is obtained. Based on this location space, a discrete search method is used to obtain a location set with N discrete points, and the location that maximizes the third optimization problem is selected from this location set as the final location of the sending clamping unit.

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