Vodacom and MTN have disputed findings by University of the Western Cape researcher Carlos Rey-Moreno, which said the operators didn’t fully utilise their spectrum along the N2 in the Eastern Cape.
Rey-Moreno conducted a drive test in 2017 using GSMTrack, plotting the signal level measured in two radio frequency spectrum bands along an 80.7km stretch of road.
The results of the test were presented to ICASA as part of Rey-Monero’s request for resources for community networks.
He also provided information on a community-run network named Zenzeleni, which they helped deploy in Mankosi in the Eastern Cape.
Local calls are free and calls to other networks cost half of what they would on those networks. Data prices are much lower than market prices.
Unoccupied spectrum, such as TV white spaces and the spectrum mobile networks don’t use in the Eastern Cape, could be used to benefit community-run networks, he said.
900MHz spectrum is of particular interest, as it can be used provide a wide coverage area.
Graphs from Rey-Moreno’s tests show that 1.4MHz of bandwidth assigned to Cell C between 949.3MHz and 950.7MHz has a low signal strength of between -90dBm and -80dBm.
Vodacom, MTN, and signals in Cell C’s other bandwidth assignment measured higher strengths of -60dBm to -10dBm. However, significant chunks registered at around -80dBm.
Vodacom and MTN said they are using the 900MHz band extensively, however.
“We use our full 900MHz spectrum ubiquitously, barring a few spots on the road such as where the road cuts through low or unpopulated, and mountainous areas,” said Vodacom.
In certain mountainous areas, terrain blocks the signal from servicing sites in the area.
“We provide 2G and 3G voice and data services on the 900MHz band on this stretch of road, as would commonly be the case throughout SA.”
MTN said it has refarmed the 900MHz frequency in this area to deploy 3G services (UMTS 900). This is in addition to the 2G/GSM layer in the area.
“Given traffic demand, site densification of layers will likely occur,” said MTN.
On the 1,800MHz test, Vodacom said it generally uses spectrum in this band to provide 4G voice and data services.
Prioritisation is given to populated areas, including small villages and towns.
“Vodacom still continues to deploy 4G on the 1,800MHz band to all sites,” it said.
This means as expansions take place, temporarily-unused spectrum becomes occupied.
“Bringing 4G to everywhere on the national roads forms part of this plan.”
In certain cases, Vodacom is still using the 1,800MHz band to provide 2G services where demand for such capacity exists.
“Due to its limited propagation characteristics, there may still be small gaps between base stations, especially along vast stretches of road where it may look like 1,800MHz spectrum is not fully used, but this is only a function of the frequency’s propagation.”
MTN echoed Vodacom’s explanation, saying it uses 1,800MHz spectrum as a capacity layer.
“In this environment, it is expected that coverage holes can be experienced due to the terrain. This we manage and circumvent as the need arises.”
Share the spectrum
On whether it would be open to sharing spectrum, Vodacom said it is always willing to engage any party that can help spread connectivity.
However, it pays for spectrum licences issued by ICASA for national use – and their use is governed by ICASA.
“Vodacom’s intention remains to use its full 1,800MHz spectrum on all its existing sites. We continue to grow our broadband coverage, especially in rural and deep rural areas, where we need access to all our spectrum bands.”
Any potential sharing of spectrum resources would severely constrain its rollout programme and subsequent network coverage, said Vodacom.
MTN said networks deployed in bands earmarked for mobile services can’t be done in isolation of a plan for the larger area.
“Interference and optimisation are a significant factor to manage,” said MTN.
It said it is investigating low-cost mobile network solutions to serve low-density communities, where traditional models are too costly.
Cell C and Telkom
Cell C and Telkom did not comment about their spectrum usage in the area tested.
Telkom does not have a spectrum assignment in the 900MHz band.