CN103260164B - A kind of cell frequency distribution method and cell frequency distribution system - Google Patents

Abstract

The present invention provides a cell frequency allocation method and a cell frequency allocation system. The cell frequency allocation method includes: obtaining the cell risk degree of each cell in the frequency planning area, wherein the cell risk degree of the cell is in the frequency planning area The sum of the correlation strengths of the signals of all the other cells in the cell; from the cells in the frequency planning area without frequency allocation, select the cell with the highest risk of the current cell, and calculate the risk of the current cell The frequency is allocated to the largest cell until all the cells in the frequency planning area are allocated frequencies, wherein the frequency allocated to the cell with the highest risk of the current cell has the least interference with the cell to which the frequency has been allocated. The present invention can improve the rationality of frequency allocation.

Description

A cell frequency allocation method and cell frequency allocation system

technical field

The invention relates to the technical field of wireless networks, in particular to a cell frequency allocation method and a cell frequency allocation system.

Background technique

In the prior art, when allocating frequencies to cells in a wireless network, a simulation method is usually used to estimate the degree of interference between the cells, and then allocate frequencies to the cells according to the degree of interference between the cells. Using the simulation method to estimate the degree of interference between cells cannot objectively reflect the actual network conditions, resulting in unreasonable results of cell frequency allocation.

Contents of the invention

In view of this, the present invention provides a cell frequency allocation method and a cell frequency allocation system, which can improve the rationality of frequency allocation.

In order to solve the above problems, the present invention provides a cell frequency allocation method, including:

Acquiring the cell risk degree of each cell in the frequency planning area, where the cell risk degree of the cell is the sum of the correlation strengths of the signals of all other cells in the frequency planning area to the signal of the cell;

From the unallocated cells in the frequency planning area, select the cell with the highest degree of risk in the current cell, and allocate frequencies to the cell with the highest degree of risk in the current cell, until all the cells in the frequency planning area are allocated Until all frequencies are allocated, the frequency allocated to the cell with the highest degree of risk of the current cell has the least interference with the cell to which the frequency has been allocated.

Optionally, the acquiring the cell risk degree of each cell in the frequency planning area includes:

Obtain the signal strength Pi of any cell i in the frequency planning area at each point in its coverage area, and the signal strength of other cells j in the frequency planning area except cell i at this point Pj;

Determine whether the difference between Pi and Pj is less than the predetermined interference threshold lim, if yes, set the degree of influence e(j-i) of the signal of cell j on the signal of cell i at this point to 1, otherwise, set the signal of cell j at this point The degree of influence e(j-i) on the signal of cell i is set to 0;

Obtain the integral of e(j-i) at all points in the coverage area of cell i on its coverage area, as the correlation strength E(j-i) of the signal of cell j to the signal of cell i;

The sum of correlation strengths of signals of all other cells in the frequency planning area with respect to the signal of cell i is obtained as the cell risk degree of cell i.

Optionally, the formula for calculating the correlation strength E(j-i) of the signal of cell j to the signal of cell i is as follows:

E(j-i)=∮e(j-i)dxdy

$\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; lim</span>}<span\; class="notranslate">\; ;</span>\\ \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; lim</span>}<span\; class="notranslate">\; ;</span>\end{array}\right.$

Among them, e(j-i) is the influence degree of the signal of cell j on the signal of cell i at any point in the coverage area of cell i, Pj is the signal strength of cell j at this point, and Pi is the signal strength of cell i at this point , lim is a predetermined interference threshold.

Optionally, the acquiring the cell risk degree of each cell in the frequency planning area includes:

dividing the frequency planning area into a plurality of equal-sized and continuous square grids;

Searching for a first type of grid in the grid corresponding to cell i, wherein the difference between the signal strength of cell i in the first type of grid and the signal strength of cell j in the first type of grid is less than a predetermined interference threshold;

Obtain the total number of the first type grids in the cell i, as the correlation strength E(j-i) of the signal of the cell j to the signal of the cell i;

The sum of correlation strengths of signals of all other cells in the frequency planning area with respect to the signal of cell i is obtained as the cell risk degree of cell i.

Optionally, the first type of grid does not include the second type of grid, wherein the difference between the minimum signal strength of cell i in its coverage area and the signal strength of cell j in the second type of grid less than the predetermined interference threshold.

The step of allocating frequencies to the cell with the highest risk degree of the current cell includes:

Get all currently available frequencies;

Substituting all the currently available frequencies into an objective function for evaluating the quality of frequency planning, and obtaining a frequency that makes the objective function reach an optimal value;

The frequency at which the objective function reaches an optimal value is used as the frequency of the cell with the highest risk degree of the current cell.

The present invention also provides a cell frequency allocation system, including:

A risk acquisition module, configured to acquire the cell risk of each cell in the frequency planning area, where the cell risk of the cell is the ratio of the signals of all other cells in the frequency planning area to the signal of the cell sum of correlation strengths;

A frequency allocation module, configured to select the cell with the highest risk degree of the current cell from the cells with no frequency assigned in the frequency planning area, and allocate a frequency to the cell with the highest risk degree of the current cell until the frequency is Until all the cells in the planning area are allocated frequencies, the frequency allocated to the cell with the highest risk degree of the current cell has the least interference with the cell to which the frequency has been allocated.

Optionally, the risk acquisition module includes:

A signal strength acquisition module, configured to acquire the signal strength Pi of any cell i in the frequency planning area at each point in its coverage area, and other cells j in the frequency planning area except cell i the signal strength Pj at that point;

The first judging module is used to judge whether the difference between Pi and Pj is less than the predetermined interference threshold lim, if yes, set the degree of influence e(j-i) of the signal of cell j on the signal of cell i at this point to 1, otherwise, set At this point, the influence degree e(j-i) of the signal of cell j on the signal of cell i is set to 0;

The integration module is used to obtain the integral of e(j-i) at all points in the coverage area of cell i on its coverage area, as the correlation strength E(j-i) of the signal of cell j to the signal of cell i.

The first risk calculation module is configured to obtain the sum of correlation strengths of signals of all other cells in the frequency planning area with respect to the signal of cell i, as the cell risk of cell i.

Optionally, the formula for calculating the correlation strength E(j-i) of the signal of cell j to the signal of cell i is as follows:

E(j-i)=∮e(j-i)dxdy

$\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; lim</span>}<span\; class="notranslate">\; ;</span>\\ \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; lim</span>}<span\; class="notranslate">\; ;</span>\end{array}\right.$

Among them, e(j-i) is the influence degree of the signal of cell j on the signal of cell i at any point in the coverage area of cell i, Pj is the signal strength of cell j at this point, and Pi is the signal strength of cell i at this point , lim is a predetermined interference threshold.

Optionally, the risk acquisition module includes:

A division module, configured to divide the frequency planning area into a plurality of equal-sized and continuous square grids;

The second judging module is configured to search for a first type of grid in the grid corresponding to cell i, wherein the signal strength of cell i in the first type of grid is the same as that of cell j in the first type of grid The difference between the signal strengths is less than the predetermined interference threshold;

The grid number acquisition module is used to obtain the total number of the first type of grid in the cell i, as the correlation strength E(j-i) of the signal of the cell j to the signal of the cell i;

The second risk calculation module is configured to acquire the sum of correlation strengths of signals of all other cells in the frequency planning area with respect to the signal of cell i, as the cell risk of cell i.

Optionally, the first type of grid does not include the second type of grid, wherein the difference between the minimum signal strength of cell i in its coverage area and the signal strength of cell j in the second type of grid less than the predetermined interference threshold.

Optionally, the frequency allocation module also includes:

The available frequency obtaining module is used to obtain all currently available frequencies;

An optimization module, configured to substitute all currently available frequencies into an objective function for evaluating the quality of frequency planning, and obtain a frequency that enables the objective function to reach an optimal value;

An execution module, configured to use the frequency at which the objective function reaches an optimal value as the frequency of the cell with the highest risk in the current cell.

The present invention has the following beneficial effects:

By obtaining the risk degree of the cell, the influence ability of the cell on the network is quantitatively analyzed. The risk degree of the cell can fully reflect the influence of factors such as topography and landform, and reflect the actual network status, so that the result of frequency allocation is more reasonable.

Description of drawings

FIG. 1 is a schematic flow chart of a cell frequency allocation method according to an embodiment of the present invention;

FIG. 2 is a schematic flow diagram of a method for obtaining a cell risk degree according to an embodiment of the present invention;

FIG. 3 is another schematic flowchart of a method for obtaining a cell risk degree according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a cell frequency allocation system according to an embodiment of the present invention.

detailed description

Before describing the embodiments of the present invention, concepts involved in the embodiments of the present invention will be briefly described first.

The cell risk degree, also called the cell complexity, is used to characterize the influence degree of the signal of the cell on the signal of surrounding cells. The greater the cell risk of a cell, the more cells that may interfere with it, and the greater the impact of the frequency allocation scheme of this cell on the quality of the frequency allocation result. The opposite is the opposite.

In the embodiment of the present invention, before allocating frequencies to the cells in the frequency planning area, the cell risk degree of each cell in the frequency planning area is first obtained, and when allocating frequencies, the cell with the highest current cell risk degree is first selected, and Allocate the frequency for the cell with the highest degree of risk in the current cell, and then select the cell with the highest degree of risk in the current cell again from the cells with no frequency assigned, and allocate the frequency for the cell with the highest degree of risk in the current cell, and make the frequency for the cell with the highest degree of risk in the current cell The frequency allocated by the cell with the highest degree of interference has the smallest interference with the cell that has allocated the frequency. And so on, until all the cells in the frequency planning area have been allocated frequencies.

Since the greater the risk of the cell, the greater the impact of its frequency allocation plan on the quality of the frequency allocation results, therefore, the frequency is first allocated to the cell with the highest risk of the current cell, and the frequency allocated to other cells is guaranteed to be consistent with the risk of the current cell. The interference between the cells with the largest degree is the smallest, so that the frequency allocation is more reasonable.

As shown in Figure 1, it is a schematic flow chart of a cell frequency allocation method according to an embodiment of the present invention. The cell allocation method is applied in a wireless network and includes the following steps:

Step 101, obtain the cell risk degree of each cell in the frequency planning area, wherein the cell risk degree of the cell is the sum of the correlation strengths of the signals of all other cells in the frequency planning area to the signal of the cell ;

Step 102, selecting the cell with the highest risk degree of the current cell from the cells without frequency allocation in the frequency planning area;

Step 103, allocating a frequency to the cell with the highest degree of risk in the current cell, wherein the frequency allocated to the cell with the highest degree of risk in the current cell has the least interference with the cell to which the frequency has been allocated;

If the cell that currently needs to be allocated a frequency is the first cell that is allocated a frequency, that is, the cell is the most dangerous cell among all the cells in the frequency planning area, any frequency can be selected for the cell for allocation.

Step 104, judging whether there are still cells with no frequency assigned, if yes, then end, otherwise, return to step 102.

Usually, the automatic frequency allocation method is related to three parts: interference model, objective function and algorithm, among which the objective function is used to evaluate the frequency allocation quality of the wireless network.

For the most dangerous cell among the unallocated frequency cells, all available frequencies can be substituted into the objective function to obtain the frequency that makes the objective function reach the optimal value, which is the ideal frequency of the most dangerous cell.

Through the above method, the frequency can be allocated to the most dangerous cell so as to minimize interference with other allocated frequency cells.

For different frequency allocation methods, the objective functions are also different, which will be described with examples below.

Objective function example one:

$\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span>$

in,

N is the number of all cells in the frequency planning area;

i ∈ [1, N], j ∈ [1, N];

A(j-i): If cell j and cell i are adjacent cells, it is 1; if cell j and cell i are not adjacent cells, it is 0;

F(j-i): If the allocated frequencies of cell j and cell i are the same, it is 1; if they are different, it is 0;

The objective function counts the co-frequency phenomena in adjacent cells in the planning area, and reflects the quality of frequency allocation accordingly.

Objective function example two:

$\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span>$

in,

N is the number of all cells in the frequency planning area;

i ∈ [1, N], j ∈ [1, N]

The value of X(j-i) comes from the inter-cell interference table, which is created before frequency planning starts. This table is the extreme statistics of network interference, which describes the area and traffic situation of each cell that will be affected by all potential interference.

Example of inter-cell interference table

source cell interfering cell co-channel interference Adjacent channel interference 1 2 500 20 1 3 100 2 … … … … 2 1 … … … … … …

As shown in the above table, when cell 1 and cell 2 have the same frequency, cell 1 will receive the same frequency interference from cell 2, and the interference amount is 500; Interference, the amount of interference is 20.

Of course, in the embodiment of the present invention, other objective functions for evaluating the frequency allocation quality of the wireless network may also be used, and no further examples are given here.

The method for obtaining the cell risk degree of the cell will be described in detail below.

To determine the cell risk degree of a cell, it is first necessary to determine a network frequency planning characteristic data module (also called a network interference model).

(1) Network frequency planning characteristic data model (network interference model)

Assuming that there are N cells in the frequency planning area, cell i is any cell in the frequency planning area, and cell j is other cells in the frequency planning area except cell i, where i∈[1,N], j∈ [1,N].

The coverage area of cell i is Si. For a certain point (i.e. signal sampling point) in the coverage area Si, suppose the signal strength of cell i’s signal at this point is Pi(dBm), and the signal strength of cell j’s signal at this point is The intensity is Pj (dBm), and at this point the influence degree of the signal of cell j on the signal of cell i is e(j-i), because the influence of the signal of cell j on the signal of cell i acts on the entire coverage area of cell i Si, so the overall influence degree E(j-i) of the signal of cell j on the signal of cell i is equal to the integral of e(j-i) in the coverage area Si, that is:

E(j-i)=∮e(j-i)dxdy

The calculation method of e(j-i) for the influence degree of the signal of cell j on the signal of cell i at a certain point in the coverage area Si is described below:

Order: e(j-i)=f(j-i)

and,

Wherein, lim is a preset interference threshold, which can be set as required.

It can be seen from the above calculation method that E(j-i) reflects the size of the area where Pi-Pj<lim(dB) in the main coverage area Si of cell i.

In the embodiment of the present invention, the overall influence degree E(j-i) of the signal of cell j on the signal of cell i may also be referred to as the "correlation strength" of the signal of cell j to the signal of cell i.

According to the above calculation method, the "correlation strength" corresponding to each cell in the frequency planning area can be calculated in sequence, and a matrix used to characterize the correlation strength of the cell can be obtained, which is the above-mentioned network frequency planning characteristic data model.

(2) The risk degree of the community i

The cell risk degree of cell i is the sum of the correlation strength (correlation strength) of the signals of all other cells in the frequency planning area to the signal of cell i;

Let the risk degree of cell i be Di, then:

${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span>$

Among them, i∈[1,N], j∈[1,N], i≠j.

Based on the above description, as shown in FIG. 2, the method for obtaining the cell risk degree in the embodiment of the present invention may include the following steps:

Step 201, obtain the signal strength Pi of any cell i in the frequency planning area at each point in its coverage area, and the signal strength Pi of other cells j in the frequency planning area except cell i at this point The signal strength of Pj;

Step 202, judging whether the difference between Pi and Pj is less than the predetermined interference threshold lim, if yes, execute step 203, otherwise, execute step 204;

Step 203, set the degree of influence e(j-i) of the signal of cell j on the signal of cell i to 1 at this point;

Step 204, the degree of influence e(j-i) of the signal of cell j on the signal of cell i at this point is set to 0;

Step 205, obtaining the integral of e(j-i) on all points in the coverage area of cell i on its coverage area, as the correlation strength E(j-i) of the signal of cell j to the signal of cell i;

The calculation formula of the correlation strength E(j-i) of the signal of the cell j to the signal of the cell i is as follows:

E(j-i)=∮e(j-i)dxdy

$\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; lim</span>}<span\; class="notranslate">\; ;</span>\\ \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; lim</span>}<span\; class="notranslate">\; ;</span>\end{array}\right.$

Among them, e(j-i) is the influence degree of the signal of cell j on the signal of cell i at any point in the coverage area of cell i, Pj is the signal strength of cell j at this point, and Pi is the signal strength of cell i at this point , lim is a predetermined interference threshold.

Step 206, acquiring the sum of correlation strengths of signals of all other cells in the frequency planning area with respect to the signal of cell i, as the cell risk degree of cell i.

In addition, in order to reduce the amount of calculation, the continuous point calculation process of the integral in the above cell risk degree acquisition method can be transformed into a discrete point calculation process, which will be described in detail below.

Specifically, the entire frequency planning area may be gridded, that is, the frequency planning area is divided into a plurality of equal-sized and continuous square grids, and then the first type of grid in the grid corresponding to cell i is searched, wherein, The difference between the signal strength of cell i in the first type grid and the signal strength of cell j in the first type grid is less than a predetermined interference threshold, and then, obtain the total The number is taken as the correlation strength E(j-i) of the signal of cell j to the signal of cell i.

According to the above calculation method, the "cell correlation strength" corresponding to each cell in the frequency planning area can be calculated sequentially, and a matrix used to characterize the cell correlation strength is obtained, which is the above-mentioned network frequency planning characteristic data model.

In the above embodiment, the setting of the side length d of the square grid may comprehensively consider the amount of calculation and the accuracy of the calculation result, for example, d=10m to 50m may be set.

Based on the above description, as shown in FIG. 3 , the cell risk degree acquisition method in the embodiment of the present invention may include the following steps:

Step 301, dividing the frequency planning area into a plurality of equal-sized and continuous square grids;

Step 302, searching for a first type of grid in the grid corresponding to cell i, wherein the difference between the signal strength of cell i in the first type of grid and the signal strength of cell j in the first type of grid is The difference is less than the predetermined interference threshold;

Step 303, obtaining the total number of the first type grids in the cell i, as the correlation strength E(j-i) of the signal of the cell j to the signal of the cell i;

Step 304, acquiring the sum of correlation strengths of signals of all other cells in the frequency planning area with respect to the signal of cell i, as the cell risk degree of cell i.

In addition, theoretically speaking, as the distance increases, the signal strength of the cell will only decay to infinitesimal, but will not disappear. However, in the process of actually calculating the correlation strength of the signal of cell j to the signal of cell i, if in the coverage area Si of cell i, the signal strength of cell j is smaller than the minimum signal of cell i in its coverage area by lim (dB) of the grid, it does not need to participate in the calculation, thus, can further reduce the amount of calculation.

That is to say, the above-mentioned first type of grid does not include the second type of grid, wherein the minimum signal strength of cell i in its coverage area is different from the signal strength of cell j in the second type of grid The difference is less than the predetermined interference threshold.

In the above embodiment, by obtaining the risk degree of the cell, the influence ability of the cell on the network is quantitatively analyzed. The risk degree of the cell can fully reflect the influence of factors such as topography and landform, and reflect the actual network status, so that the result of frequency allocation more reasonable.

As shown in Figure 4, it is a schematic structural diagram of a cell frequency allocation system according to an embodiment of the present invention, and the cell frequency allocation system includes:

The risk acquisition module 401 is configured to acquire the cell risk of each cell in the frequency planning area, wherein the cell risk of the cell is the signal of all other cells in the frequency planning area to the signal of the cell The sum of the correlation strengths of ;

The frequency allocation module 402 is configured to select the cell with the highest risk degree of the current cell from the cells with no frequency assigned in the frequency planning area, and allocate a frequency to the cell with the highest risk degree of the current cell until the Until all the cells in the frequency planning area are allocated frequencies, the frequency allocated to the cell with the highest risk degree of the current cell has the least interference with the cell with the allocated frequency.

Preferably, the above risk acquisition module 401 may include the following functional modules:

A signal strength acquisition module, configured to acquire the signal strength Pi of any cell i in the frequency planning area at each point in its coverage area, and other cells j in the frequency planning area except cell i the signal strength Pj at that point;

The first judging module is used to judge whether the difference between Pi and Pj is less than the predetermined interference threshold lim, if yes, set the degree of influence e(j-i) of the signal of cell j on the signal of cell i at this point to 1, otherwise, set At this point, the influence degree e(j-i) of the signal of cell j on the signal of cell i is set to 0;

The integration module is used to obtain the integral of e(j-i) at all points in the coverage area of cell i on its coverage area, as the correlation strength E(j-i) of the signal of cell j to the signal of cell i.

The first risk calculation module is configured to obtain the sum of correlation strengths of signals of all other cells in the frequency planning area with respect to the signal of cell i, as the cell risk of cell i.

The calculation formula of the correlation strength E(j-i) of the signal of the cell j to the signal of the cell i is as follows:

E(j-i)=∮e(j-i)dxdy

$\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; l</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ;</span>\\ \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; P</span>}\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; lim</span>}<span\; class="notranslate">\; ;</span>\end{array}\right.$

Among them, e(j-i) is the influence degree of the signal of cell j on the signal of cell i at any point in the coverage area of cell i, Pj is the signal strength of cell j at this point, and Pi is the signal strength of cell i at this point , lim is a predetermined interference threshold.

Preferably, the above risk acquisition module 401 may also include the following functional modules:

A division module, configured to divide the frequency planning area into a plurality of equal-sized and continuous square grids;

A second judging module, configured to search for a first type of grid in the grid corresponding to cell i, wherein the signal strength of cell i in the first type of grid is the same as that of cell j in the first type of grid The difference between the signal strengths is less than the predetermined interference threshold;

The grid number acquisition module is used to obtain the total number of the first type of grid in the cell i, as the correlation strength E(j-i) of the signal of the cell j to the signal of the cell i;

The second risk calculation module is configured to acquire the sum of correlation strengths of signals of all other cells in the frequency planning area with respect to the signal of cell i, as the cell risk of cell i.

In addition, in order to reduce the amount of calculation, the first type of grid may not include the second type of grid, wherein the minimum signal strength of cell i in its coverage area is the same as that of cell j in the second type of grid The difference between the signal strengths is smaller than the predetermined interference threshold.

In order to minimize the interference between the frequency assigned to the cell with the highest degree of risk in the current cell and the cell with the assigned frequency, the frequency allocation module in the embodiment of the present invention further includes:

The available frequency obtaining module is used to obtain all currently available frequencies;

An optimization module, configured to substitute all currently available frequencies into an objective function for evaluating the quality of frequency planning, and obtain a frequency that enables the objective function to reach an optimal value;

An executing module, configured to use the frequency at which the objective function reaches an optimal value as the frequency of the cell with the highest risk in the current cell.

In the above embodiment, by obtaining the risk degree of the cell, the influence ability of the cell on the network is quantitatively analyzed. The risk degree of the cell can fully reflect the influence of factors such as topography and landform, and reflect the actual network status, so that the result of frequency allocation more reasonable.

The wireless network involved in the embodiment of the present invention may be a wireless network such as GSM and TD.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications should also be It is regarded as the protection scope of the present invention.

Claims (10)

1. A method for assigning cell frequencies, comprising:

acquiring a cell risk of each cell in a frequency planning region, wherein the cell risk of each cell is the sum of the correlation strengths of signals of all other cells in the frequency planning region to the signals of the cells, and acquiring the integral of E (j-i) on the coverage area of the cell i at all points in the coverage area of the cell i according to the influence degree E (j-i) of the signal of the cell j on the signal of the cell i, and the integral is used as the correlation strength E (j-i) of the signal of the cell j on the signal of the cell i;

selecting a cell with the highest risk of a current cell from cells without frequencies allocated in the frequency planning region, and allocating a frequency to the cell with the highest risk of the current cell until frequencies are allocated to all the cells in the frequency planning region, wherein interference between the frequency allocated to the cell with the highest risk of the current cell and the cell with the allocated frequency is the minimum, and the method comprises the following steps: acquiring all current available frequencies; substituting all the current available frequencies into an objective function for evaluating frequency planning quality to obtain the frequency for enabling the objective function to reach an optimal value; taking the frequency of the cell which makes the objective function reach the optimal value as the frequency of the cell with the maximum risk degree of the current cell, wherein the objective function isN is the total number of cells in the frequency plan area, i ∈ [1, N]，j∈[1，N]The value of X (j-i) comes from the inter-cell interference table, which is created before the start of the frequency planning, which is an extreme statistic of the network interference, describing the area of the area and the traffic volume each cell will be affected by all potential interference.

2. The cell frequency allocation method of claim 1, wherein said obtaining the cell risk of each cell in the frequency plan region comprises:

acquiring the signal intensity Pi of any cell i in the frequency planning region at each point in the coverage area of the cell i and the signal intensity Pj of other cells j except the cell i in the frequency planning region at the point;

judging whether the difference between Pi and Pj is smaller than a preset interference threshold lim, if so, setting the influence degree e (j-i) of the signal of the cell j on the signal of the cell i at the point to be 1, otherwise, setting the influence degree e (j-i) of the signal of the cell j on the signal of the cell i at the point to be 0;

acquiring the integral of E (j-i) on the coverage area of the cell i at all points in the coverage area of the cell i as the correlation strength E (j-i) of the signal of the cell j to the signal of the cell i;

and acquiring the sum of the correlation strengths of the signals of all other cells in the frequency planning region to the signal of the cell i as the cell risk of the cell i.

3. The cell frequency allocation method according to claim 2, wherein the correlation strength E (j-i) of the signal of cell j to the signal of cell i is calculated as follows:

E(j-i)＝∮e(j-i)dxdy

$e(j-i)=f(j-i)=\left\{\begin{array}{c}1,Pi-Pj<\lim ;\\ 0,Pi-Pj\&GreaterEqual;\lim ;\end{array}\right.$

wherein e (j-i) is the influence degree of the signal of the cell j on any point of the signal of the cell i in the coverage area of the cell i, Pj is the signal strength of the cell j at any point, Pi is the signal strength of the cell i at any point, and lim is the predetermined interference threshold.

4. The cell frequency allocation method of claim 1, wherein said obtaining the cell risk of each cell in the frequency plan region comprises:

dividing the frequency planning region into a plurality of square grids which are equal in size and continuous;

searching a first type grid in grids corresponding to a cell i, wherein the difference between the signal intensity of the cell i in the first type grid and the signal intensity of the cell j in the first type grid is smaller than a preset interference threshold;

acquiring the total number of the first type grids in the cell i as the correlation strength E (j-i) of the signal of the cell j to the signal of the cell i;

and acquiring the sum of the correlation strengths of the signals of all other cells in the frequency planning region to the signal of the cell i as the cell risk of the cell i.

5. The cell frequency allocation method of claim 4, wherein a second type of mesh is not included in said first type of mesh, wherein a difference between a minimum signal strength of cell i in its coverage area and a signal strength of cell j in said second type of mesh is less than a predetermined interference threshold.

6. A cell frequency allocation system, comprising:

a risk degree obtaining module, configured to obtain a cell risk degree of each cell in a frequency planning region, where the cell risk degree of each cell is a sum of correlation strengths of signals of all other cells in the frequency planning region to the signals of the cells, and obtain, according to a degree E (j-i) of an influence of a signal of a cell j on a signal of a cell i, an integral of E (j-i) at all points in a coverage area of the cell i over the coverage area thereof, as a correlation strength E (j-i) of the signal of the cell j on the signal of the cell i;

a frequency allocation module for allocating a small number of unassigned frequencies from the frequency plan regionSelecting a cell with the highest risk of a current cell from the cells, and allocating frequencies to the cell with the highest risk of the current cell until all the cells in the frequency planning region are allocated with frequencies, wherein the interference between the frequency allocated to the cell with the highest risk of the current cell and the cell with the allocated frequency is the minimum; the method comprises the following steps: the available frequency acquisition module is used for acquiring all current available frequencies; the optimization module is used for substituting all the current available frequencies into an objective function for evaluating frequency planning quality to obtain the frequency for enabling the objective function to reach an optimal value; an executing module, configured to use the frequency that the objective function reaches an optimal value as the frequency of the cell with the highest risk of the current cell, where the objective function isN is the total number of cells in the frequency plan area, i ∈ [1, N]，j∈[1，N]The value of X (j-i) comes from the inter-cell interference table, which is created before the start of the frequency planning, which is an extreme statistic of the network interference, describing the area of the area and the traffic volume each cell will be affected by all potential interference.

7. The cell frequency allocation system of claim 6, wherein the risk level acquisition module comprises:

a signal strength obtaining module, configured to obtain a signal strength Pi of any cell i in the frequency planning region at each point in a coverage area of the cell i, and a signal strength Pj of other cells j except the cell i in the frequency planning region at the point;

a first judging module, configured to judge whether a difference between Pi and Pj is smaller than a predetermined interference threshold lim, if so, set an influence degree e (j-i) of a signal of a cell j at the point on a signal of a cell i to 1, otherwise, set an influence degree e (j-i) of the signal of the cell j at the point on the signal of the cell i to 0;

an integration module, configured to obtain an integration of E (j-i) at all points in a coverage area of the cell i over the coverage area thereof, as a correlation strength E (j-i) of a signal of the cell j to a signal of the cell i;

and the first risk calculation module is used for acquiring the sum of the correlation strengths of the signals of all other cells in the frequency planning region to the signal of the cell i as the cell risk of the cell i.

8. The cell frequency allocation system according to claim 7, wherein the correlation strength E (j-i) of the signal of cell j to the signal of cell i is calculated as follows:

E(j-i)＝∮e(j-i)dxdy

$e(j-i)=f(j-i)=\left\{\begin{array}{c}1,Pi-Pj<\lim ;\\ 0,Pi-Pj\&GreaterEqual;\lim ;\end{array}\right.$

wherein e (j-i) is the influence degree of the signal of the cell j on any point of the signal of the cell i in the coverage area of the cell i, Pj is the signal strength of the cell j at any point, Pi is the signal strength of the cell i at any point, and lim is the predetermined interference threshold.

9. The cell frequency allocation system of claim 6, wherein the risk level acquisition module comprises:

the dividing module is used for dividing the frequency planning region into a plurality of continuous square grids with equal size;

a second judging module, configured to search a first type grid in grids corresponding to a cell i, where a difference between a signal strength of the cell i in the first type grid and a signal strength of the cell j in the first type grid is smaller than a predetermined interference threshold;

a grid number obtaining module, configured to obtain the total number of the first type grids in the cell i as a correlation strength E (j-i) of a signal of the cell j to a signal of the cell i;

and the second risk degree calculation module is used for acquiring the sum of the correlation strengths of the signals of all other cells in the frequency planning region to the signal of the cell i as the cell risk degree of the cell i.

10. The cell frequency allocation system of claim 9 wherein no mesh of a second type is included in said mesh of a first type, wherein the difference between the minimum signal strength of cell i in its coverage area and the signal strength of cell j in said mesh of a second type is less than a predetermined interference threshold.