CN109041003B - Radio frequency energy source arrangement method based on greedy algorithm - Google Patents

Abstract

A radio frequency energy source arrangement method based on a greedy algorithm selects an arrangement position of an energy source by utilizing the greedy algorithm aiming at the conditions of a given node position, a radio frequency energy source candidate arrangement position and the number of energy sources to be arranged, the algorithm defines an effective energy capture power increment of a certain candidate position as the sum of node effective energy capture power increments after an energy source is arranged at the candidate position, and the energy sources are arranged one by iteratively executing the following operations: among the candidate positions where the energy sources have not been placed, the candidate position having the largest effective energy capture power increment is selected, and one energy source is placed at the candidate position. The method of the invention realizes reasonable selection of the arrangement position of the radio frequency energy source and can achieve larger total effective energy capture power.

Description

Radio frequency energy source arrangement method based on greedy algorithm

Technical Field

The invention relates to a radio frequency energy source arrangement method based on a greedy algorithm, which is suitable for a wireless sensor network with sensor nodes capable of capturing radio frequency energy.

Background

Electromagnetic waves are increasingly receiving attention from both academic and industrial circles as a ubiquitous, environmentally friendly and sustainable energy source. The radio frequency energy capturing wireless sensor network is a novel network for capturing radio frequency energy in an environment and converting the radio frequency energy into electric energy so as to support continuous work of nodes.

However, at present, the rate of capturing the radio frequency energy in the environment by the radio frequency energy capturing sensor node is still very low, which is one of the bottlenecks in the wide application of this kind of new networks. To overcome this weakness, it is a feasible and effective method to deploy a dedicated radio frequency energy source to power the nodes.

Since the radio frequency energy can lose a certain amount of energy in the transmission process, namely the farther the energy source is away from the node, the less radio frequency energy is captured by the node, and the energy capture power of the node depends on the arrangement position of the energy source. In addition, the node often has an energy capture power demand value, for example, the value is the average power consumption of the node, and the excess part of the actual capture power exceeding the demand value does not bring any benefit. Therefore, for the given scene of the node position for capturing the radio frequency energy, the candidate arrangement positions of the radio frequency energy sources and the number of the energy sources to be arranged, a reasonable arrangement position is selected from the candidate arrangement position set, so that the total effective capturing power of the node is larger, and the method is an important problem to be solved by a radio frequency energy capturing network.

Disclosure of Invention

In order to overcome the defect that the total node effective capture power of the conventional radio frequency energy source arrangement method is small, the radio frequency energy source arrangement method based on the greedy algorithm is provided according to the given node position for capturing the radio frequency energy, the radio frequency energy source candidate arrangement position and the number of the energy sources to be arranged, and the energy capture power requirement value of the node is considered, so that the large total node effective capture power is achieved.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a radio frequency energy source arrangement method based on a greedy algorithm comprises the following steps:

step 1, for i ═ 1,2, …, M and j ═ 1,2, …, N, where M is the number of nodes capturing radio frequency energy and N is the number of candidate placement positions of the radio frequency energy source, calculating the power p captured by the ith node from the energy source placed at the jth candidate placement position according to formula (1)_i,j：

Where eta represents the rectification efficiency, G_sRepresenting the antenna transmission gain, G, of the energy source_rRepresents the node antenna reception gain, L_pRepresents polarization loss, λ represents wavelength, d_i,jIs the distance between the ith node and the jth candidate placement location, and P is the energy transmission power of the energy source;

step 2. initialize C ═ C₁,c₂,…,c_NIn which c is_iInitializing for the ith candidate placement position, C for the set of N candidate placement positions

Where C' is a selected set of locations at which energy sources are to be deployed, i.e.

Step 3, setting n to be 0;

step 4. for i ═ 1,2, …, M, order

Wherein

Capturing power for the current effective energy of the ith node;

step 5, for each candidate position C in C \ C_kCalculating the increment of the effective energy capture power after the last energy source is arranged according to the formula (2)

Wherein

Is the energy capture power requirement value of the ith node;

step 6, selecting the candidate position set C \ C' with the maximum

That candidate position c of value_kLet C'. U { C_k}；

Step 7. for i ═ 1,2, …, M, let

Step 8, n ← n +1, if n ═ K, go to step 9, otherwise go to step 5, where K is the number of energy sources to be arranged;

step 9. determining the arrangement position of the energy source according to C', namely for each C_jE.g. C', placing an energy source at the jth candidate position;

and step 10, ending.

The invention has the beneficial effects that: according to the position of a given node for capturing radio frequency energy, the candidate arrangement position of the radio frequency energy source and the number of the energy sources to be arranged, the node is considered to have an energy capturing power demand value, and the larger total effective capturing power of the node is achieved.

Drawings

FIG. 1 is a flow chart of a greedy algorithm based RF energy source arrangement method of the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Referring to fig. 1, a radio frequency energy source arrangement method based on a greedy algorithm includes the following steps:

step 1, for i ═ 1,2, …, M and j ═ 1,2, …, N, where M is the number of nodes capturing radio frequency energy and N is the number of candidate placement positions of the radio frequency energy source, calculating the power p captured by the ith node from the energy source placed at the jth candidate placement position according to formula (1)_i,j：

Where eta represents the rectification efficiency, G_sRepresenting the antenna transmission gain, G, of the energy source_rRepresents the node antenna reception gain, L_pRepresents polarization loss, λ represents wavelength, d_i,jIs the distance between the ith node and the jth candidate placement location, and P is the energy transmission power of the energy source;

step 2. initialize C ═ C₁,c₂,…,c_NIn which c is_iInitializing for the ith candidate placement position, C for the set of N candidate placement positions

Where C' is a selected set of locations at which energy sources are to be deployed, i.e.

Step 3, setting n to be 0;

step 4. for i ═ 1,2, …, M, order

Wherein

Capturing power for the current effective energy of the ith node;

step 5, for each candidate position C in C \ C_kCalculating the increment of the effective energy capture power after the last energy source is arranged according to the formula (2)

Wherein

Is the energy capture power requirement value of the ith node;

step 6, selecting the candidate position set C \ C' with the maximum

That candidate position c of value_kLet C'. U { C_k}；

Step 7. for i ═ 1,2, …, M, let

Step 8, n ← n +1, if n ═ K, go to step 9, otherwise go to step 5, where K is the number of energy sources to be arranged;

step 9. determining the arrangement position of the energy source according to C', namely for each C_jE.g. C', placing an energy source at the jth candidate position;

and step 10, ending.

Specific embodiments of the present invention are described for such scenarios given the node location where the rf energy is captured, the candidate placement locations for the rf energy sources, and the number of energy sources to be placed.

First, according to the physical position of each node and the physical position of each candidate arrangement position, each node and each candidate arrangement position are calculatedA distance between each candidate placement position. Then, for j ═ 1,2, …, N, the power p captured by each node from the energy source disposed at the jth candidate disposition location is calculated_i,j。

Set initialization and parameter initialization are then performed. Let C be { C ═ C₁,c₂,…,c_NIn which c is_iFor the ith candidate placement position, C is a set of N candidate placement positions, and

where C' is a selected set of locations at which energy sources are to be deployed, i.e.

For i ═ 1,2, …, M, order

Wherein

Capturing power for the current effective energy of the ith node.

A candidate location is then iteratively selected to add to the selected location. In each iteration, for each candidate position in C \ C ', the increment of the effective energy capture power when the last energy source is arranged is calculated, the candidate position with the largest increment is selected and added into the selected position C'. And continuously and iteratively increasing the selected energy source deployment positions until the number K of the energy sources needing to be arranged is reached.

After the iteration is over, the arrangement of the energy sources is determined according to C', i.e. for each C_jE C', an energy source is placed at the jth candidate location.

Claims (1)

1. A radio frequency energy source arrangement method based on a greedy genetic algorithm is characterized by comprising the following steps:

step 1, for i ═ 1,2, …, M and j ═ 1,2, …, N, where M is the number of nodes capturing radio frequency energy, N is the number of candidate placement locations of the radio frequency energy source, rootCalculating the power p captured by the ith node from the energy source arranged on the jth candidate arrangement position according to the formula (1)_i,j：

Where eta represents the rectification efficiency, G_sRepresenting the antenna transmission gain, G, of the energy source_rRepresents the node antenna reception gain, L_pRepresents polarization loss, λ represents wavelength, d_i,jIs the distance between the ith node and the jth candidate placement location, and P is the energy transmission power of the energy source;

step 2. initialize C ═ C₁,c₂,…,c_NIn which c is_iInitializing for the ith candidate placement position, C for the set of N candidate placement positions

Where C' is a selected set of locations at which energy sources are to be deployed, i.e.

Step 3, setting n to be 0;

step 4. for i ═ 1,2, …, M, order

Wherein

Capturing power for the current effective energy of the ith node;

step 5, for each candidate position C in the set C \ C_kCalculating the increment of the effective energy capture power after the last energy source is arranged according to the formula (2)

Wherein

Is the energy capture power requirement value of the ith node;

step 6, selecting the C \ C' with the maximum

That candidate position c of value_kLet C'. U { C_k}；

Step 7. for i ═ 1,2, …, M, let

Step 8, n ← n +1, if n ═ K, go to step 9, otherwise go to step 5, where K is the number of energy sources to be arranged;

step 9. determining the arrangement position of the energy source according to C', namely for each C_jE.g. C', placing an energy source at the jth candidate position;

and step 10, ending.

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