Frequently Asked Questions

Quality of Service (QoS)

  1. What are the guiding documents on Quality of Service?

    Answer: The following are the principal guiding documents for Quality of Service regulation;
    • QoS Regulation 2012. This regulation can be accessed via the link below: http://www.ncc.gov.ng/licensing-regulatory/legal/regulations
    • The Nigerian Communications Act 2003. The Act can be accessed via the link below: http://www.ncc.gov.ng/documents/128-nigerian-communications- act-2003/file

  2. What is Quality of Service

    Answer: Quality of service (QoS) is the collective effect of service performance which determines the degree of satisfaction of a user of the service indicating the performance of a network and of the degree to which the network conforms to the stipulated norms.

  3. Why are QoS standards important?

    Answer: The QoS standards ensure that consumers continue to have access to high quality telecommunications service by setting basic minimum quality levels for all operators. These standards define the lower and upper bounds of acceptability of such issues as Call Setup Success Rate, Call Drop Rate, Handover Success Rate, call completion rates, etc. and commercial consumer issues such as access to customer care centres, billing integrity and other characteristics that can be measured and improved.

  4. Why does QoS matters?

    Answer: Quality of service is a major factor in ensuring optimum consumer/provider relations because by demanding a certain ‘quality of service ‘the consumer is empowered to:
    • Select the service provider that best satisfies their specific needs
    • Obtain optimum value for money
    • Judge the level of service with which they are provided
    • Evaluate service level Agreements correctly
    • Make informed decisions.

  5. What levels of service should the consumer expect?

    Answer: The consumer is entitled to expect the following levels of service or quality of service provision:
    • Value for money
    • Ease of use of the service or product
    • Professionalism, on the part of the service provider, in the provision of the service.
    • Flexibility in the use of the service on the part of the consumer for instance, the ease with which the consumer is able to switch from one operator to another, from one resource to another, etc.
    • The product or service should perform according to expectations and as specified.
    • The consumers are well informed and make an informed choice

  6. What are the QoS metrics being used by NCC to assess the performance of operators?

    Answer: NCC currently uses 13 QoS metrics and are clearly defined in the NCC website.
    1. The technical parameters for 2G are enumerated below:
      1. Call Setup Success Rate (Number of the unblocked call attempts divided by the total number of call attempts. Or (1 - Blocking Probability) x 100%.
      2. Drop Call Rate (The Dropped Call Rate (sometimes called Call Drop Rate) is the number of dropped calls divided by the total number of call attempts. Or (1 - Call Completion Ratio) x 100%)
      3. Traffic Channel Congestion Rate (This is the percentage congestion of the TCH measured at the busy hour)
      4. Stand-Alone Dedicated Channel Congestion (Dropped SDCCH Connections of the Total Number of SDCCH Connections without TCH Congestion)
      5. Handover Success Rate (This is the ratio of the number of successfully completed handovers to the total number of initiated handovers. This ratio can be expressed as a percentage)
      6. Call Completion Rate (The ratio of successfully completed calls to the total number of attempted calls (ITU-T E600/2.13). That is, the ratio of the number of completed call attempts to the total number of call attempts, at a given point of a network)
      7. Route Congestion (This is the percentage congestion of the Circuits measured at busy hour).
      8. Route Availability (Amount of time the routes were in/out of service during a given period excluding planned outage
      9. Cell Availability (Amount of time cells were in/out of service during a given period excluding planned outage)
      10. Call Setup Time (Time interval between the end of dialing by the user and the reception by him of the appropriate ring back tone or recorded announcement, or the abandonment of the call without a tone.
      11. Mean Opinion Score (is the speech quality perceived by Caller or Called party in accordance with ITU-T P.862.
      12. Answer Seizure Ratio (ASR) (is the ratio of the number of successful calls over the total number of outgoing calls from a carrier’s network (i.e. On a route or a Destination Point Code (DPC) basis, and during a specified time interval, the ratio of the number of seizures that result in an answer signal to the total number of seizures: ITU-T E600/2.14).
      13. Post Dialing Delay (In GSM network, is the average time between pressing send button (after pressing correct digits) and getting a ring back tone. This is also called “Call Setup Time” or time to connect a call)
    2. The technical parameters for 3G are enumerated below:
      1. Call Setup Success Rate (PS)
      2. Call Setup Success Rate (CS)
      3. RRC connection establishment success rate (PS)
      4. RRC connection establishment success rate (CS)
      5. RAB Establishment Success Rate
      6. HSUPA Setup Success Ratio [%] for Streaming(S), Interactive(I) and Background(B) Services
      7. HSDPA Setup Success Ratio [%] for Streaming(S), Interactive(I) and Background(B)
      8. Iub Congestion ix. RRC Congestion
      9. Circuit Switched RAB Congestion
      10. Paging Success Rate
      11. CS RAB Abnormal Release Rate
      12. PS RAB Abnormal Release Rate
      13. Soft Handover Success Rate
      14. Inter RAT Handover Success Rate for CS Domain
      15. Cell Availability (or Node-B Accumulated downtime (not available for service)
      16. Average Downlink Throughput per User
      17. CS Call setup time (CST) for on-net calls

  7. How do NCC measure the performance of operators?

    Answer: The following are the methods used by the NCC to measure the performance of operators.
    • Monthly visitation to operators Network Operating Centers (NOC) to collect raw data of the Key performance Indicators for the purpose of analysis.
    • Drive test in some major cities.
    • Automatic collation of QoS data from operators systems and automatic Subscriber perceived QoS measurements.

  8. Why is it that some subscribers experience unacceptable QoS in some locations in a month, but the QoS performance result published on the NCC website shows that the operators met their QoS KPI targets for the month?

    Answer: The QoS KPI performance report is reported as an average at the national and state levels respectively. Hence an area may be having a challenge with QoS but when the QoS performance in the area is averaged with other areas in the state or at the national level, the averaged result is usually better than unacceptable QoS experienced in any one of the component locations. However, NCC engages operators to ensure the QoS performance challenges in any of the identified locations are resolved.

  9. What are In-Building Solutions (IBS)?

    Answer: IBS are a system of distributed antennas and base station equipment meant to provide telecommunications coverage in enclosed locations like high rise buildings, large buildings, hotels, shopping malls, offices etc. IBS are needed in these buildings as the telecommunications signal from external sites deployed by operators are absorbed by the building walls and fading degradation of the signal with increasing distance from the telecommunications site.

  10. Why is it that sometimes when calls are made to people whose lines are switched on, a message saying the subscriber is unavailable is received?

    Answer: This is due to any or a combination of the following reasons:
    1. The subscriber is in an area with minimal network coverage due to:
      1. The called subscriber being in an location with little or no network coverage like high rise or large buildings or shopping malls without In-building solutions
      2. The called subscriber may be on the highway with no network coverage
      3. The called subscriber may be at the outskirt of town with no network coverage
      4. The shutdown of the operator site serving the area by a landlord, site shutdown due to theft of operator site generator, theft of batteries, theft of diesel, security issues in accessing the site, or community issues preventing an operator from servicing the impacted site, or site shutdown by agencies of government, etc.
      5. Cut in the fibre optic cable that conveys all the calls made in a group of sites across the country due to construction activities, vandalisation, etc.
    2. The subscriber handset may be of sub-standard
    3. Planning and optimization errors from operators

  11. Why does a subscriber experience dropped calls?

    Answer: The following are some of the reasons subscribers experience dropped calls.
    1. Inability of operator to deploy required new sites due to difficulties in acquiring new site locations to deploy their equipment
    2. Sub-optimal definition of neighboring cells by operators
    3. Inability of operator to cover the site operational expenses for a site to be deployed in the location
    4. Inadequate network capacity