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RRC 04/05 ITU Information meeting September 18-19 2003 Computer methods for planning Ken Hunt Rapporteur for Chapter 10.

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Presentation on theme: "RRC 04/05 ITU Information meeting September 18-19 2003 Computer methods for planning Ken Hunt Rapporteur for Chapter 10."— Presentation transcript:

1 RRC 04/05 ITU Information meeting September Computer methods for planning Ken Hunt Rapporteur for Chapter 10

2 RRC 04/05 ITU Information meeting September The purpose of Chapter 10 is to assist the RRC by describing how basic elements of planning methods might be implemented. It is not the purpose of Chapter 10 to describe the implementation of any specific planning method. The planning method or methods to be used for the RRC and the intersessional work will need to be defined by the first session of the RRC. Basic purpose of Chapter 10

3 RRC 04/05 ITU Information meeting September Chapter 10 starts with higher level elements likely to be needed in planning methods. It then works its way downwards towards the basic components of such methods. It is assumed that most readers will not need to look at the detail of the basic components, that is items after §§ This presentation starts with the lowest level to show how the components may be assembled into higher level elements. Construction of Chapter 10

4 RRC 04/05 ITU Information meeting September The computer methods described in Chapter 10 are intended for application to any service or combination of services. The detail of how the methods are applied may differ to some extent, but there are no fundamental differences. Service types

5 RRC 04/05 ITU Information meeting September The propagation prediction method(s) will need to be defined by the first session of the RRC. The implementation descriptions in Chapter 10 do not depend on any particular propagation prediction method. For non-terrestrial services, some form of near free-space model will need to be defined by the RRC. For terrestrial services, it is likely that many different propagation zone types will need to be considered. Field strength at a destination 1

6 RRC 04/05 ITU Information meeting September Possible propagation zone types in and near Africa

7 RRC 04/05 ITU Information meeting September The proportion of a propagation path in each zone type will need to be found. Note if the signal source is a transmitter or a reference network. Take account of the frequency, the effective antenna height and the required percentage of time. Using the agreed propagation prediction model, find the field strength for an effective radiated power (erp)of 1 kW. Take account of the erps in the horizontal and vertical planes in the direction of propagation. Field strength at a destination 2

8 RRC 04/05 ITU Information meeting September The result of the calculation is two field strength values, one for each plane of polarisation. In the case where the signal source has only horizontal or vertical polarisation, the field strength in the other plane of polarisation may be set to a low value. Field strengths at a destination 3

9 RRC 04/05 ITU Information meeting September In the case of a fixed receiving antenna, its directivity and polarisation discrimination should be taken into account. In the case where the reception mode is portable or mobile, the receiving antenna is likely to have neither directivity nor polarisation discrimination. Receiving antenna discrimination

10 RRC 04/05 ITU Information meeting September For any given pair of transmission and reception service types there will be a set of protection ratio values. The protection ratio to be applied in any given circumstances will also depend on the frequency separation between the centre frequencies. Protection ratio consideration

11 RRC 04/05 ITU Information meeting September In the case of multiple wanted signals, for example in a single frequency network, it is necessary to calculate the sum of the signals received. This is likely to be done by means of one of the statistical methods so that the impact on the distribution of field strength with location may also be taken in to account. Similarly, it is likely that in the case of multiple interfering signals, a statistical method will be used to determine the sum and standard deviation. The combined effect of multiple wanted and interfering signals may also be calculated using a statistical method to give a combined location correction factor. Signal summation

12 RRC 04/05 ITU Information meeting September The wanted field strength at a receiving location may be calculated from: –the co-ordinates of the receiving and transmitting locations; –the characteristics of the receiving antenna; –the field strength calculated as previously described. Wanted field strength at a receiving location

13 RRC 04/05 ITU Information meeting September The nuisance field strength at a receiving location may be calculated from: –the co-ordinates of the receiving and transmitting locations; –the characteristics of the receiving antenna and the relative bearings of the wanted and interfering signals; –the field strength calculated as previously described; –the relevant protection ratio. Nuisance field strength at a receiving location

14 RRC 04/05 ITU Information meeting September The protection margin at a receiving location is: –the wanted field strength minus –the nuisance field strength minus –the combined location correction factor. where these three elements are calculated as previously described. The protection margin concept may be applied to any combination of wanted and interfering services. Protection margin

15 RRC 04/05 ITU Information meeting September In many cases, it will be necessary to calculate the distance from a signal source at which a given field strength is reached. This may be done in an iterative process in order to take account of any combination of propagation zone types along the propagation path. The basic element is the calculation of a field strength for a given destination, as previously described. Distance for a given field strength

16 RRC 04/05 ITU Information meeting September The size of a coverage area along any given radial may be calculated by iteration, taking account of: –the distance at which a given field strength can be achieved; –the protection margin at that location; –any adjustment of the distance in order to achieve a protection margin of zero. The size of a service area may be determined from the size of the coverage area taking account of any relevant national boundaries (subject to any decisions in this regard by the RRC). Size of coverage area

17 RRC 04/05 ITU Information meeting September Digital broadcasting requirements are likely to have some definition of their boundaries by means of test points. Potential incompatibilities between pairs of requirements may be determined by: –examining if there is any potential coverage overlap; –examining if there is potential harmful interference. An initial assumption is that they have overlapping channels. Incompatibilities between digital broadcasting requirements

18 RRC 04/05 ITU Information meeting September Overlapping coverage 1

19 RRC 04/05 ITU Information meeting September Overlapping coverage 2

20 RRC 04/05 ITU Information meeting September Interference source is a transmitter Interference calculation 1

21 RRC 04/05 ITU Information meeting September Interference source is a set of reference networks Interference calculations 2

22 RRC 04/05 ITU Information meeting September If the interference source is a transmitter: –calculations must be made from the transmitter to every test point of the requirement. If the interference source is a reference network: –Calculations must be made from every test point of the requirement to every test point of the other requirement. In general, nothing is known of the details of each propagation path and these must be determined individually. The overall result is a list of potential incompatibilities. Interference calculations 3

23 RRC 04/05 ITU Information meeting September Any potential incompatibility between a digital broadcasting requirement and an other service requirement may assessed by: –calculating the potential interference on the assumption that the digital broadcasting requirement is assigned to each channel successively. The result is an identification of the channels available to each digital broadcasting requirement. Incompatibilities between digital broadcasting requirements and other service requirements

24 RRC 04/05 ITU Information meeting September Any of the results of the incompatibility calculations may be modified by means of declarations from the administrations concerned. All of the calculations details will need to be decided by the RRC. The basic components described in Chapter 10 may be used to build complex methods intended to meet the needs of the RRC. Administrative declarations and RRC decisions


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