| 7.1 | Cross Border Frequency Coordination will abide by the Harmonised Calculation Method for Africa (HCM4A) Agreement. This follows the 3rd CRASA AGM 26 and 28 March 2014, Lesotho Sun Hotel Maseru, Lesotho that agreed that CRASA should implement the Cross Border Frequency Coordination Harmonised Calculation Method for Africa (HCM4A) Agreement. |
| 7.2 | The ECC had noted the need for a greater understanding of the concept and the need for harmonisation in the signing of the HCM4A Agreement by the SADC Member States if the implementation of the Agreement is to be effective. The ECC, therefore, agreed to convene a workshop on HCM4A and requested the CRASA Members to consider signing the agreement. These activities were part of the Frequency Planning Sub Committee (FPSC) Operations Plan 2015/16. |
| 7.3 | At the 5th CRASA AGM, Swakopmund, Namibia – 07-08 April 20169, the subject of Cross Border Frequency Coordination using the HCM4A was discussed in detail, following similar efforts in Europe. The Resolution CRASA/AGM/15.16/07 stipulates, “The AGM urged CRASA Members to prioritise the motivation to their administrations who are yet to indicate their interest to sign the Harmonised Calculation Method for Africa (HCM4A), to do so as soon as possible”. |
| 7.3.1 | Therefore, coordination would follow the HCM4A10 as detailed in Sub-Saharan Africa Assessment Report on Harmonisation of ICT Policies in Sub-Saharan Africa (HIPSSA)11. |
| 7.4 | A harmonised calculation method (HCM4A12) brings these benefits: |
| 7.4.1 | Alignment with International Best Practice |
| 7.4.2 | Optimised spectrum usage; |
| 7.4.3 | Prevention of harmful interferences |
| 7.4.4 | Conferring of adequate protection for stations; |
| 7.4.5 | Defining of technical provisions and administrative procedures; |
| 7.4.6 | Quick assignment of preferential frequencies; |
| 7.4.7 | Transparent decisions through agreed assessment procedures; |
| 7.4.8 | Quick assessment of interference through data exchange. |
| 7.5 | HCM4A involves all four (4) sub-regions of Africa. This means the HCM4A projects include performing a survey and a comparative analysis of existing administrative and technical procedures related to bilateral and multilateral cross-border frequency coordination agreements across the four (4) geographical sub-regions as defined by the African Union (AU), namely: |
| 7.5.1 | Central Africa [Burundi, Central African Republic, Chad, Congo, Democratic Republic of Congo, Equatorial Guinea, Gabon, Sao Tome, and Principe]; |
| 7.5.2 | East Africa [Comoros, Djibouti, Eritrea, Ethiopia, Kenya, Madagascar, Mauritius, Rwanda, Seychelles, Somalia, Sudan, Tanzania, Uganda]; |
| 7.5.3 | Southern Africa [Angola, Botswana, Lesotho, Malawi, Mozambique, Namibia, South Africa, Swaziland, Zambia, Zimbabwe]; |
| 7.5.4 | West Africa [Benin, Burkina-Faso, Cape Verde, Côte d’Ivoire, Gambia, Ghana, Guinea, Guinea-Bissau, Liberia, Mali, Niger, Nigeria, Sierra Leone, Senegal, Togo]. |
| 7.6 | HCM4A also comes with a software tool for the Coordination of the Spectrum Resources in Sub-Saharan Africa in order to13: |
| 7.6.1 | Optimising spectrum usage by accurate interference field strength calculations; |
| 7.6.2 | Establishing general parameters, improvement, and supplementation of technical provisions, individual restrictions; |
| 7.6.3 | Establishing models for computer-aided interference range calculations; |
| 7.6.4 | Harmonising parameters: objectively predictable towards transparent decisions. |
| 7.7 | Use of 2300 - 2400 MHz frequency bands will require coordination with the neighbouring countries within the coordination zones of six (6) kilometres from the neighbouring country. The coordination distance is continuously being reviewed and these may be updated from time to time. |
| 7.8 | The following field strength thresholds have to be assured, with any necessary operator-to-operator coordination to avoid interference: |
7.8.1. TDD to TDD, based on ECC/REC (14)04:
The 2300 - 2400 MHz band may be used for TDD systems without coordination if the mean field strength of each cell produced by the base station does not exceed a value of 30 dBμV/m/5 MHz at a height of 3 metres above ground level at the border line between countries.
Synchronisation, including the field strength levels, should be achieved by the operators if TDD is in operation across both sides of a border.
When TDD systems are synchronised across the border, the 2300-2400 MHz band may be used without coordination with a neighbouring country if the mean field strength of each cell produced by the base station does not exceed a value of 65 dBμV/m/5MHz at a height of 3 metres above ground level at the border line between countries and a value of 49 dBμV/m/5MHz at a height of 3 m above ground level at a distance of 6 km inside the neighbouring country.
When preferential and non-preferential spectrum blocks are defined in the 2300-2400 MHz band and are distributed between neighbouring countries, coordination is not required if the mean field strength of each cell produced by the base station does not exceed the specified limits and any coordination adheres to the specified requirements (as provided for in Appendix C):
| • | for the preferential blocks, a value of 65 dBμV/m/5 MHz at a height of 3 metres above ground level at the border line between two (2) countries and a value of 49 dBμV/m/5 MHz at a height of 3 m above ground level at a distance of 6 km inside the neighbouring country; |
| • | for non-preferential blocks, a value of 30 dBμV/m/5 MHz at a height of 3 m above ground level at the borderline between two countries. |
The “mean field strength of each cell” refers to a frequency block of 5 MHz14.
For field strength predictions the calculations should be made according to Appendix B. In cases of other frequency block sizes, 10 x log10 (frequency block size / 5 MHz) should be added to the field strength values.
If South Africa and its neighbouring administrations, namely Botswana (Republic of), Eswatini (Kingdom of), Lesotho (Kingdom of), Namibia (Republic of) Mozambique (Republic of) and Zimbabwe (Republic of), wish to agree on frequency coordination based on preferential frequencies, whilst ensuring equitable treatment of different operators within a country, the Authority will add these into the mutual agreements.
As per ECC/REC (11) 05 of the 26th May 2011, the cross-border operation between TDD and TDD systems and between TDD and FDD systems, stations of IMT systems may be operated without coordination if the mean field strength produced by the cell (all transmitters within the sector) does not exceed the value of 21 dBμV/m/5 MHz at 10% time, 50% of locations at 3 metres above ground level at the border line.
ECC/REC (14)04 and ECC/REC (11)05 may offer guidance for additional scenarios (NB! The general FDD case is only included in the original ECC/REC (11)05 dated 26 May 2011, and not in the latest version published on 03 February 2017 15).
| 7.9 | Technical analysis may be conducted by the Authority before an assignment is issued according to Appendix B based on an extract from ECC/REC (14)04. |
| 7.10 | Specific information regarding coordination may be found in Appendix B based on an extract from ECC/REC (14)04. |
| 7.11 | In the event of any interference, the Authority will require affected parties to carry out coordination. In the event that the interference continues to be unresolved after 24 hours, the affected parties may refer the matter to the Authority for a resolution. The Authority will decide the necessary modifications and schedule of modifications to resolve the dispute. The Frequency Coordination Process will guide the Authority as shown in Appendix D. |
| 7.12 | Assignment holders must take full advantage of interference mitigation techniques such as antenna discrimination, tilt, polarisation, frequency discrimination, shielding / blocking (introduce diffraction loss), site selection, and/or power control to facilitate the coordination of systems. |
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| 9 | https%3A%2F%2Fextranet.crasa.org%2Fzip-agm.php%3Fid%3D332&usg=AOvVaw1bVAuEnE8a2iJnP20F_b_2 |
| 10 | https://www.itu.int/en/ITU-D/Projects/ITU-EC-ACP/PRIDA/PublishingImages/Pages/default/HCM4A_2022_%20Main%20text_and%20annex%2012%20_EN_v.0.pdf |
| 11 | https://www.itu.int/en/ITU-D/Projects/ITU-EC-ACP/HIPSSA/Documents/FINAL%20DOCUMENTS/FINAL%20DOCS%20ENGLISH/hcm4a_agreement.pdf.pdf |
| 12 | Cross-Border Frequency Coordination: Harmonised Calculation Method for Africa (HCM4A) |
| 13 | PowerPoint Presentation (itu.int) https://www.itu.int/en/ITU-D/Regional-Presence/AsiaPacific/Documents/Events/2017/May%20BKK/Presentations/HCM%20and%20HCM4A%20BKK%202017050 4%20IB.pdf |
| 15 | https://docdb.cept.org/document/501 |
