Engineering Departmental 




Managing the Spectrum and network Resource as per ITU standards – Planning, assigning , monitoring and interference resolution


  KPIs Definitions

1. Stand-alone Dedicated Control Channels (SDCCH) drop rate: SDDCH is a signaling channel that exists between GSM Mobile and GSM Base Station. The SDCCH is used for most short transactions, including initial call setup step, registration and SMS transfer. The SDCCH call drop rate indicates the probability of call drops when the MS occupies the SDCCH. The acceptable threshold for this KPI is below 1.5%.    

 2. Traffic channels – TCH Drop Rate: are the combination of voice and data signals (me slot assignments) that exit within a communication channel. The TCH call drop rate refers to the ratio of call drops to successful TCH seizures after the BSC successfully assigns TCHs to MSs. The acceptable threshold for this KPI is below 2%. 

3. The TCH congestion rate: is the proportion of the number of TCH assignment failures to the number of TCH seizure requests. If the TCH congestion rate is high, the network service quality deteriorates. The acceptable threshold for this KPI is below 1.5%. 

4. The Call Setup Success Rate (CSSR): indicates the probability of successful calls initiated by the MS. The CSSR is an important KPI for evaluating the network performance. If this KPI is too low, the subscribers are not likely to make calls successfully. The acceptable threshold for this KPI is above 95%. 

5. Handover Success Rate (HOSR): is an important function in mobile communication systems. As a means of radio link control, handover enables users to communicate continuously when they traverse different cells. The acceptable threshold for this KPI is above 95%. 

6. Network Availability: This KPI calculation gives percentage values of the site availability on the network. The acceptable threshold for this KPI is above 75%. In the future NATCOM would be uploading all list of all equipment that have been type approved by the commission. The commission would also in the future sign an agreement with the Ghana regulatory authority so the commission would be sending some equipment to their lab for testing  

 Strategic context: Telecommunication sector outlook 

Availability of Services

  • In general, consumers in Sierra Leone have seen investment in Mobile and broadband network and services.
  • FM, VHF, UHF

Competition in mobile telecoms

  • Access to spectrum has been used as a means of promoting competition between the mobile operators.
  • Investment in 3G and 4G networks have resulted in relatively high mobile broadband coverage and a choice of service provider

Supporting the following Aims

  • Provision of services that are affordable and set at competitive prices;
  • Fit for purpose regulations that support policies to:
  • protect the interests of consumers
  • protect further investments
  • creative business model to target the development of the digital economy.
  • Foster competition and a sustainable ICT environment to support a digital economy;
  • Elimination of barriers to competition in network services through:
  • Open standards and inter connectivity
  • Efficient spectrum planning, assignment and monitoring


  1. Abdul Bah, Director of Engineering & Infrastructure
  2. Desmond Macfoy, Deputy Director of Engineering & Infrastructure
  3. Melvin King, Manager, Quality of Service
  4. Thomas Jusu, Spectrum Manager
  5. Marian N. Yarjah, IT Manager