WO1999000920A1

WO1999000920A1 - Method for searching for useable transmission frequencies for television and radio broadcasting systems

Info

Publication number: WO1999000920A1
Application number: PCT/EP1998/002895
Authority: WO
Inventors: Jochen Scheinert
Original assignee: Deutsche Telekom Ag
Priority date: 1997-06-27
Filing date: 1998-05-16
Publication date: 1999-01-07
Also published as: DE19727301A1; CZ297539B6; HUP0002200A3; DE59812517D1; EP0992136B1; PL337525A1; ATE288157T1; CZ474599A3; EP0992136A1; HUP0002200A2; DE19727301C2

Abstract

The invention relates to a method for determining additional frequencies for radio broadcasting networks or similar. Using a constantly updated database of co-ordinated transmitters and a topology database, the inventive method optimises the quality of frequency planning, the necessary measurements, coverage plots etc.. The desired parameters for the new transmitter are inputted and every frequency in the chosen frequency range which fulfils the respective conditions for successful co-ordination is automatically determined by an information processing tool or an information processing device connected to the aforementioned databases. The method helps determine for example all the effects on the co-ordinated VHF broadcasting network, and tests the suitability of each frequency in an e.g. 100 kHz grid in the entire VHF band or in a partial range, according to the predetermined criteria. The method thus provides all the frequencies which can be co-ordinated in accordance with the predetermined conditions. The useable field strengths are determined and provided at the same time. The frequency planners then only need to test the frequencies given and optionally make a decision. The inventive method uses a more accurate allowance for the topography (diffraction models) in addition to the statistical propagation model, in order to increase accuracy.

Description

DESCRIPTION

METHOD FOR SEARCHING USEFUL TRANSMITTER FREQUENCIES FOR TV AND BROADCASTERS

The invention relates to a method for searching usable transmission frequencies for TV and radio stations according to the preamble of claim 1.

The procedures for national coordination and international coordination of radio stations are based on nationally and / or internationally agreed regulations of a technical nature, such as the International Telecommunication Union (ITU). The spectrum for broadcasting services in Central Europe is already very densely populated and therefore coverage up to the minimum useful field strength is usually not possible. The coverage area of a transmitter is predominantly limited or disrupted by the interference influences of other transmitters on the same or adjacent frequency. Based on this fact, planning additional frequencies is usually a redistribution of coverage. Since the interference range of a transmitter is greater than its coverage range, part of the supply potential of the frequency range is lost in this process. Scheduling additional transmitters is only possible if the associated impairment of existing, coordinated transmitters can be accepted.

Due to the dense occupancy, the search for additional frequencies, for example in the FM frequency band 87.5 to 108.0 MHz, is increasing. So far, the selection of the frequencies in question has been made according to the lowest usable field strength (field strength range). This method can hardly be used successfully today. Therefore, extensive measurements, Coordination calculations and preparation of pension plans required. An effective information processing method for automated frequency search is not yet known.

The invention is therefore based on the object of providing a method for searching usable transmission frequencies for TV and FM radio stations or the like, which theoretically determines all frequencies, for example in the FM band or a sub-range thereof, which could successfully pass through the coordination , whereby all effects, for example on the coordinated VHF transmitter network, are determined and the suitability of each frequency in a frequency grid in the respective frequency band or in a sub-range is to be examined according to the respectively specified criteria in order to obtain as a result all frequencies which correspond to the given conditions could be coordinated, so that after checking the frequencies determined, a clear decision is finally possible by the frequency planner.

The achievement of the object is characterized in the characterizing part of patent claim 1.

Further solution features or refinements of the method according to the invention are characterized in claims 2 to 12.

The method determines all effects on the coordinated VHF transmitter network or TV transmitter network and examines the suitability of each frequency according to predefined criteria, for example in a 100 kHz grid in the entire VHF band or in a sub-area. The result is all frequencies that could be coordinated according to the given conditions. At the same time, the usable field strength is determined and specified. For The frequency planner then has the task of finally checking the frequencies determined and deciding which one is used. The statement becomes more precise the more the effort for checking the coordination conditions is increased and the more precise the calculation methods are. Therefore, for example, in addition to the statistical propagation model, the more precise consideration of the topography (diffraction models) is also included.

The present method is carried out with the aid of an information processing system, the following data and information processing modules being required:

1. Data

Current file of the coordinated characteristic features of the radio or TV stations of the respective radio service in the planning area and up to 800 km in the neighborhood. This database should be back-dated, i.e. it must be possible to simulate the transmitter network to a state at a previous time when a particular transmitter was scheduled,

current topographical file of the planning area and up to approx. 800 km in the neighborhood,

if available, file with the interference contours and test points, as well as reception locations of the transmitters of the respective radio service in the planning area and up to 800 km in the neighborhood. 2. Information processing modules

Module (s) for calculating the distances, protective distances and decouplings based on the applicable recommendations of the International Telecommunication Union (ITU) and national agreements.

Module (s) for calculating field strengths and interference factors based on the applicable recommendations of the International Telecommunication Union (ITU), such as ITU-R PN.370 and national agreements.

Module (s) for calculating the field strengths and interference factors on the basis of agreed diffraction models using a topographical database for field strength calculation on the basis of the applicable guidelines and agreements.

Module for calculating the usable field strength according to the agreed multiplication method, power sum method or other recommended method.

Module for the calculation according to the method of single disturbance analysis.

The following entries must also be made:

Parameters of the desired transmitter (characteristic features),

Start and end frequency of the frequency range to be examined, minimum interference factor up to the affected transmitter should be taken into account,

Test points that are to be examined on and within the respective supply contour of the transmitters concerned (fixed points, grid and the like),

Receiving locations that are to be examined in the coverage area of the transmitters concerned (fixed points, grid and the like),

permissible influences on affected transmitters (increase in the usable field strength at test points of disturbed transmitters, falling below the protective distance at receiving locations, etc.),

Permissible change to the desired characteristic features of the transmitter (additional maximum diagram indentation according to "criterion of usable field strength", additional maximum diagram indentation according to "criterion single interference analysis" or the like).

The invention will be explained in more detail with reference to an operation sequence shown in the flow chart according to FIG. 1.

The flowchart according to FIG. 1 shows the basic method steps for the frequency search for TV and radio stations or the like. First, a compatibility check with the existing transmitter network is carried out. The calculation is carried out, for example, in 100 kHz steps (FM) in the selected frequency range, starting from the start frequency to the end frequency. So the parameters and the frequency range of the desired transmitter are defined. First, the usable field strength for the respective frequency at the location of the new transmitter is determined and saved. This value is used for Evaluation of the "potential quality of supply / possibility with this frequency".

Then all transmitter locations in the same and neighboring channels (e.g. FM range -400 to +400 kHz to the respective frequency) are determined at which the interference factor exceeds the specified limit, such as 34 dB. These stations are sorted according to the interference factor. Starting with the transmitter with the highest interference factor, the change in the usable field strength at the location, on the supply contour is calculated either from the existing file or in each case by calculation and at predetermined or determined (scheme / grid) test points. If the value for the permissible increase is exceeded, the interference factor is reduced until the permissible increase is observed.

The reduction in the interference factor is saved as the required additional diagram indentation, marked with "criterion usable field strength". Since the change in the usable field strength is considered at the time of the respective transmitter being included in the plan (birth value), only backdating brings an exact result. However, you can use a threshold value for the current network. Subsequently, at predetermined reception locations, which can either be stored in a file or calculated according to a scheme / grid, in the coverage area of the transmitter concerned, it is examined whether there is a fall below the protective distance. According to today's rules (e.g. BAPT 313 RL 02), only those locations are permitted where the useful field strength is reached and which have not been affected so far, i.e. the protective distances of interfering signals and criteria for reflections are observed. If the safety distance is undershot, the interference factor is reduced until there is no longer a shortfall. The reduction in the interference factor is saved as the required additional diagram indentation, marked with "Criterion for individual interference analysis". These examinations can be carried out using a diffraction model or other known forecasting methods.

Now the next disturbed transmitter is examined until all determined affected transmitters have been calculated. Once all the transmitters concerned have been calculated, the channel is considered as:

Category 1,

"suitable for usable field strength and suitable for

Single disturbance analysis ", or

Category 2

"suitable according to usable field strength and not suitable according to single interference analysis", or

Category 3,

"not suitable according to usable field strength and suitable according to single interference analysis" or

Category 4,

"not suitable according to usable field strength and not suitable according to single interference analysis", saved as result.

After the end of the calculation for all channels in the specified frequency range, the channels of all categories are sorted according to the value of the usable field strength at the "Location" test point. Once all channels have been calculated, the frequencies determined as suitable and the respective usable field strength with the respective possible transmission parameters and further calculation results are output.

The results are then evaluated. Ideally, the frequency with the lowest usable field strength is suitable. First the category 1 result list is checked. If there are suggestions in this frequency, they will first be checked further for their suitability; if necessary, the characteristic features still have to be changed. If the output is positive, the frequency search is completed, which is represented by the "yes" in the flow diagram according to FIG. 1.

If no channel was found in this category ("no" in the flow chart according to FIG. 1), the calculation can either be repeated with other specifications or categories 2 and 3 can be checked for suitable channels, the characteristic features of which are then likely to be changed have to.

If no suitable frequency is determined, then certainly none can be coordinated with the characteristic features, including tolerances, and in compliance with the coordination conditions. Unless you can give special reasons or make arrangements with the coordination partners.

After changing the input values (data, inputs, different diagram, higher diagram indentation, different location, etc.), a new calculation can be carried out until a suitable frequency is determined.

To reduce the computing effort, it is still possible to use different calculation depths. To do this different sequence controls may be possible. For example, only a change in the usable field strength at the location test point can be calculated first. For the frequencies determined, the calculation is then carried out at test points on and within the interference contour or in a grid, as will be described later. The single-fault test is carried out at the same time or subsequently at reception points in the coverage area. It is also still possible to generally reduce the depth of calculation for less powerful computers, but then the effort for the subsequent check is greater.

The selection of the test points is described below. The change in the usable field strength is calculated in test points. In the FM range, for example, an increase in the usable field strength by a maximum of 0.5 dB is permitted since the time the transmitter was included in the plan. This calculation rule requires a sender database that can be back-dated for comparison calculations. If this is not possible, you have to work with a lower threshold value (e.g. 0.1 or 0.2 dB) and check it later. A special test point is always the location; for this, the calculation is made without taking into account the directivity of the receiving antenna for stereo reception with FM, analog with TV. At this test point, a rough statement about the compatibility of the planning is already possible. The receiving antenna must be taken into account at all other test points. In the VHF range, test points are only permitted on or within the interference contour, i.e. the useful field strength must be> the usable field strength.

An optimal variant is to consider the following test points: Location (without directional reception antenna),

Interference contour in 10 "steps (azimuth, starting at north over east with directional reception antenna), interference contour at the point closest to the interferer (directional reception antenna), at the shortest distance (e.g. 100 m) behind the location of the user transmitter, with the receiving antenna aligned with the interfering transmitter, at the shortest distance (for example 100 m) behind the interferer, with the receiving antenna aligned with the useful transmitter if the interferer lies within the interference contour.

In addition, further test points can be defined within the interference contour according to the system to be specified. The number of specified test points determines the computing effort or the computer runtime.

This is followed by the selection of the receiving locations. Compliance with the required safety distance is checked at reception points. This requires calculations of the field strength according to the guidelines of the International Telecommunication Union (ITU) or according to the diffraction model. However, the entire calculation for a receiving location is only carried out with one of the two models. A place of receipt is only permitted if it is considered to be supplied according to the applicable guidelines. Due to the influences of the topographical conditions, it is not possible to specify a fixed scheme for the receiving locations, which only contains meaningful receiving locations, as with the statistical methods specified above. On the one hand, unacceptable reception locations can occur and, on the other hand, unacceptable reception locations can be recorded. However, a compromise can be found to limit the computational effort, however, follow-up examinations may then be necessary. Variant for determining the receiving locations:

All test points on the interference contour are used simultaneously as receiving locations (with directional receiving antenna),

all points on the minimum useful field strength contour in 10 ^° steps (with directional reception antenna),

all points at a distance of 1 km on the radius of every 10 ° between the interference contour and the minimum useful field strength contour (with directional reception antenna),

Minimum useful field strength contour at the point with the smallest distance to the interferer (with directional reception antenna),

at the shortest distance (for example 100 meters) behind the interferer, with the receiving antenna aligned to the useful transmitter, if the interferer lies within the minimum field strength contour.

In addition, according to the system to be specified, further receiving locations can be defined inside and outside the minimum useful field strength contour. The number of specified receiving locations determines the computing effort or the computer runtime.

The raster process already mentioned will now be described below. An ideal variant, both for test points and for receiving locations, is the specification of a grid that extends beyond the range of the minimum useful field strength according to the rules of the International Telecommunication Union (ITU) or according to the diffraction model. The density of the grid should be close to that Database resolution for topographical data can be adjusted. For each point of the grid, the change in the usable field strength is calculated and the compliance with the protective distance is checked (single-fault test).

When calculating the change in the usable field strength, those points are excluded at which the previous usable field strength is smaller than the useful field strength, which makes the calculation of the interference contour (with a sufficiently dense grid) unnecessary.

The compliance with the safety distance is checked according to the criteria described under the selection of the receiving locations.

The computational effort for such a raster analysis is maximum, but a very precise result can be achieved. It should also be mentioned that the specifications / settings for calculation on the right in the flowchart, for example the minimum interference factor, permissible influences on the transmitters concerned, permissible changes to the parameters, etc. should represent. The reference calculations in the dashed box in the flowchart contain a file with already calculated values at test points, reception locations, on the interference contour, etc. for comparison and evaluation of the influences or changes.

Claims

P AT E NT AN SPÜCHE

1. A method for searching usable transmission frequencies for TV and radio stations or the like, taking into account national and international technical guidelines, characterized in that

that a current file of the coordinated characteristic features of the transmitters, which can be back-dated, a current topographical file and a file with the interference contours and test points as well as reception locations of the transmitters in the planning area and in the neighborhood are created in a memory,

that information modules for the calculation of distances, field strengths, protective distances, decouplings and interference factors are created on the basis of international guidelines,

that modules for calculating the distances, field strengths, protective distances, decouplings and interference values are generated on the basis of agreed diffraction models using the topographical database for field strength calculation,

that a module for the calculation of the usable field strength, a module for the calculation of the usable field strength and a module for the calculation according to the method of single-site consideration is generated,

that parameters which contain the characteristic features of the desired transmitter are entered into an information processing device or calculation tool. that in addition the start and end frequency of the frequency range to be examined, the minimum interference factor up to the affected transmitter should be taken into account, test points that should be examined on and within the respective coverage contour of the affected transmitter, receiving locations that are examined in the coverage area of the affected transmitter permissible influences on affected transmitters and the permissible changes to the desired characteristic features of the transmitter are to be entered into the information processing device or the calculation tool which carries out the calculation in steps in the selected frequency range, starting from the start frequency to the end frequency,

that the usable field strength for the respective frequency at the location of the new transmitter is first determined and stored,

that all transmitter locations in the same and neighboring channels are then determined and stored, at which the interference factor exceeds the intended limit,

that these determined transmitters are sorted in the memory according to the level of the interference factor,

that the change in the usable field strength at the location, on the supply contour and at predetermined test points is then calculated at predetermined receiving locations that are stored in a file or according to a scheme / grid, taking into account that the permissible protective distance is fallen short of. that if the safety distance is undershot, the interference factor is reduced until there is no longer a shortfall,

that the reduction in the interference factor is saved as the required additional diagram indentation,

that the next disturbed transmitter is then examined until all determined affected transmitters have been calculated,

that afterwards all channels concerned are stored as one of a certain defined number of categories according to the criterion "compliance with the maximum additional diagram indentation" and

that after the end of the calculation for all channels in the specified frequency range, the channels of all categories are sorted according to the value of the usable field strength at the test point, i.e. the location, and the frequencies determined as suitable and the respective usable field strength with the respective possible transmission parameters and others Calculation results are output for evaluation.

2. The method according to claim 1, characterized in

that the current file of the coordinating characteristic features of the broadcasting stations of a broadcasting service in the planning area and in the neighborhood by simulating the transmitter network to a state at a previous time Scheduling a specific transmitter is software-backdated.

3. The method according to any one of claims 1 or 2, characterized in

that the module for the calculation of the usable field strength works according to the simplified multiplication method, the module for the calculation of the usable field strength according to the power-sum method and the module for the calculation according to the method of single interference analysis.

4. The method according to any one of claims 1 to 3, characterized in

that the determined transmitters are sorted according to the level of the interference factor,

that starting with the transmitter with the highest interference value, the change in the usable field strength at the location, on the supply contour is calculated on the basis of an existing file or on the basis of calculations at predetermined test points,

that if the permissible increase is exceeded, the interference factor is reduced until the permissible increase is maintained,

that the reduction of the interference factor is saved as a required additional diagram indentation, marked with "criterion usable field strength" and

that the change in the usable field strength is related to the time of the introduction of the respective transmitter in the plan.

5. The method according to claim 4, characterized in

that instead of backdating, a certain threshold value for the current network is introduced as a reference.

6. The method according to any one of claims 4 or 5, characterized in that

that with the help of a file or according to a scheme or grid in the coverage area of the transmitter in question, the calculation tool is used to check whether there is a fall below the protective distance and in this case the interference factor is reduced until there is no longer a drop.

7. The method according to claim 1, characterized in

that the result list of category 1 is checked first,

that in the presence of frequency suggestions, these are checked, if necessary by changing the characteristic features and

that the frequency search is ended when the output is positive.

8. The method according to claim 7, characterized in

that if no channel was found in the first category, either calculate with other specifications are repeated or categories 2 and 3 are checked for suitable channels,

that if a suitable frequency is not determined, a

Change the input values for new

Arithmetic operations take place until a suitable frequency is determined.

9. The method according to any one of claims 1 to 8, characterized in

that the change in usable field strength is calculated at test points,

that an increase in the usable field strength in the FM range by a maximum of 0.5 dB has been permitted since the time the transmitter was included in the plan, and

that this calculation rule accesses a sender database that can be back-dated for comparative calculations.

10. The method according to any one of claims 1 to 9, characterized in

that in the FM range test points are only permitted on or within the interference contour, the test points being the location, the interference contour in 10 "steps, the interference contour at the point with the smallest distance from the interferer, the shortest distance behind the location of the user transmitter, with the receiving antenna aligned with the interfering transmitter and at the shortest distance behind the interferer, with the receiving antenna aligned with the user transmitter, if the interferer lies within the interference contour as Input variables can be entered into the information processing device or the calculation tool.

11. The method according to any one of claims 1 to 10, characterized in

that compliance with the required protective distance is checked at all receiving locations,

that the field strength calculations are carried out either according to international guidelines or according to the diffraction model and

that all test points on the interference contour are used simultaneously as reception locations to determine the reception locations,

that all points on the minimum useful field strength contour in 10 "steps, all points at a certain distance (for example 1 km) on the radius of every 10 ° between the interference contour and the minimum useful field strength contour, the minimum useful field strength contour at the point the smallest distance to the interferer and in the shortest distance behind the interferer, with the receiving antenna aligned to the useful transmitter, if the interferer lies within the minimum useful field strength contour.

12. The method according to any one of claims 1 to 11, characterized in

that the density of the grid (test points / receiving locations) is adapted to the resolution of the topographical database. that for each point of this grid, a calculation of the change in the usable field strength and a check of compliance with the protective distance is carried out and

that when calculating the change in the usable field strength, those points are excluded at which the previous usable field strength is smaller than the useful field strength.