Cellular network problems: The Facts
Recent media reports lambasted Vodacom, MTN and Cell C for poor network quality which results in dropped calls, busy network signals and delayed SMS delivery. The three cellular operators have been summoned by the Independent Communications Authority of South Africa (ICASA) because of the large number of complaints from consumers.
According to ICASA the situation is of concern to the regulator which is why they called on the cellular operators to explain the situation. “The mere fact that we called a meeting with them shows how concerned we are,” ICASA spokesperson Sekgoela Sekgoela is quoted as saying by The Times.
This raises the question as to exactly how bad the situation is and who is to blame for the network problems. To answer the question accurately two of the best metrics to use are ‘percentage of dropped calls’ and ‘setup success rate’.
MTN South Africa made detailed statistics available about their network stability and availability, and it proves to be higher than international standards.
According to Tim Lowry, MTN SA’s Managing Director, their network has a dropped call rate of around 1%, much lower than the international benchmark of 2%. Sameer Dave, Chief Technical Officer at MTN SA, added that the provider’s Call Setup Success Rate (CSSR) is in the region of 99.5%, again higher than international benchmarks.
Vodacom’s 2008 Annual Report indicates a CSSR of 99.8%, a call retention rate of 99.3% and call success rate of 99.1%. This translates into a dropped call rate of less than 1%.
Cell C said that their call setup success rate is 98.5% while their drop call rate is less than 1%. These figures are also in range of acceptable international standards.
SMS Delivery
When it comes to timely SMS delivery Lowry showed that over 99% of SMSs are typically delivered in less than 9 seconds. The undelivered SMSs, which are attempted to be sent for up to 6 days, can be because of a variety of factors outside of MTN’s control like the recipients handset is switched off.
Cell C said that SMSs which are not delivered are usually due to the mobile (recipient) not being reachable at the time the SMS is sent, either due to momentary loss of/low coverage that the customer (receiver) may not be aware of. “Our network system will automatically re-try until successfully sent (transmitted), as this is due to recipient network quality,” said Cell C.
Vodacom added that the capability of the cellphone being used (2G, 2.5G or 3G) can also influence the delivery of a SMS. “A 2G cellphone under normal network conditions does not allow a data session and a voice call or SMS at the same time. This could cause delayed SMSs and calls going to voice mail,” said Vodacom.
Telkom the main culprit?
MTN’s Lowry highlighted that some elements of MTN’s network quality remain beyond MTN’s control. These elements, which include electricity supplied by Eskom and transmission links from Telkom, account for around 90% of all MTN’s network faults.
The biggest point of failure in MTN’s network is links and transmission provided by Telkom, which up to recently had a monopoly on providing leased lines in South Africa. Lowry highlighted that 53.11% of all faults on the MTN network can be attributed to Telkom. Outstanding Telkom links amounting more than 5000 in MTN’s case further delay network deployments which make it difficult for the cellular provider to address network capacity issues.
Dave pointed out that MTN is looking at various ways to mitigate the risks which are beyond their control and this includes investing in their own transmission network.
Vodacom also confirmed that the vast majority of the network problems are due to transmission links currently supplied by Telkom. Vodacom is also investing heavily in its own transmission network, but according to Vodacom spokesperson Dot Field it will take time to replace legacy infrastructure and Vodacom is still to a large degree reliant on Telkom for their transmission capacity.
Cell C said that at present Telkom is the supplier of transmission throughout its network. “For all of our core transmission and major traffic routes we have redundant transmission paths and as such face very few problems from associated failures.”
“For our transmission to individual sites there is less opportunity for redundancy and subsequently there are times when these links may fail whether due to storms affecting the microwave, theft of physical cable, damage to cable due to construction works or failure of individual components within the Telkom network,” said Cell C.
“From a Cell C perspective we are impacted by these failures as we may lose coverage from an affected site for the duration of the outage. However these are monitored 24/7 by both Cell C and Telkom management centres to ensure that any problems are identified quickly and rectified with an accompanying service level agreement between the two companies.”
Publicly available network statistics
Lowry said that MTN proposed that all major licensed telecoms providers – Vodacom, MTN, Cell C, Telkom and Neotel – regularly publish information on their key network performance parameters in a consistent manner. This must include key network parameters, accurate customer base figures and network performance statistics.
MTN proposed that a committee, chaired by ICASA, is established which will determine the information to be published and how this is measured and defined. Lowry added that there should be a strong focus on the accuracy and consistency of these results. The MTN SA MD added that ICASA and all the major operators accepted this proposal.
Cellphone network problems – give your views
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