MyBroadband recently conducted drive tests in Cape Town to measure the quality of South Africa’s mobile data networks.
The results showed that MTN has the best mobile data network in Cape Town by a significant margin, and it posted the best average download and upload speeds, and latencies in the city.
MTN’s latency results were consistent in every suburb where we conducted tests and it achieved an average latency of 22 milliseconds.
It only deviated significantly from that average in Fish Hoek and Hout Bay, where it saw mean latencies of 26ms and 24ms respectively.
MTN told MyBroadband it was able to achieve this consistent, low latency thanks to the investment and upgrading of its network. The company has spent around R37 billion improving its network over the last three and a half years, it said.
“In 2018, MTN continued its active upgrading of its network through the largest network rollout ever seen in South Africa.”
An overview of the mobile network tests is shown below.
256-QAM and 4×4 MIMO
Speaking about its network upgrades, MTN said it invested in the latest cutting edge infrastructure and technologies.
This includes “Three Carrier Aggregation (3CA) or Three Carrier Combining (3CC), deployment of new radio hardware, and advanced antenna technologies such as 4×4 MIMO and 256-QAM in select areas, including Cape Town”, MTN told MyBroadband.
256-QAM is quadrature amplitude modulation which uses 256 symbols. Chipmaker Qualcomm explained that 256-QAM is a way to reduce congestion on a network by improving the efficiency with which data is transferred.
Using the analogy of a congested highway, Qualcomm likened 256-QAM to reducing the number of trucks clogging up the roads by packing 33% more data into every “truck.”
Carrier aggregation is a method for networks to combine network channels in different frequencies into a single channel with greater bandwidth. This is like widening the highway to allow more trucks on it at any given time, Qualcomm said.
MIMO is short for Multiple Input Multiple Output. This is an antenna design feature which Qualcomm explained was like building a multi-layered highway when you can’t widen it anymore.
The Samsung Galaxy S9 devices MyBroadband used to conduct the drive tests in Cape Town support all these features, and MTN’s network was therefore able to make use of carrier aggregation, 256-QAM, and 4×4 MIMO to improve its data network performance.
In addition to these technologies, MTN said it has rolled out several other improvements to its network.
“The 3CC/3CA technology has LTE900, which gives our network better speeds and better indoor coverage for LTE,” MTN said.
LTE900 refers to the frequency band in which the network is able to operate. In this case, 900MHz, which is much lower than the frequencies networks usually operate their LTE networks in. The bands you usually find LTE in are 1,800MHz, 1,900/2,100MHz, and 2,600MHz.
Operating in a lower frequency band offers better indoor signal penetration, as well as a wider coverage area.
There is a trade-off to rolling out coverage on lower frequencies, however. Networks cells can only support a set number of subscribers, which means that operators have to “densify” their coverage with smaller cells that run on higher frequencies in areas of higher population density.
They therefore usually need a combination of lower and higher frequencies to strike a balance between coverage, indoor penetration, and overall network capacity.
According to MTN, running on LTE900 results in a better experience on voice over LTE calls, improved drop call rates, and greater voice quality.
MTN said it has also implemented a “strict regime” of peering with content providers and web hosting platforms.
MTN said that all of this, combined with end-to-end latency optimisation, has given its network the latency result in Cape Town that MyBroadband measured.