The number of 4G mobile customers is catching up with those on older 3G plans, but 4G coverage indoors has been found wanting in some places still.
In a 4G speed test conducted at several commercial buildings last week, The Straits Times found that connection problems and surfing slowdowns still dog some telcos' networks although 4G services have been in use for nearly three years.
Some 3.5 million - and counting - mobile users are on 4G plans here. Many of the 4.3 million users still on 3G plans are expected to switch to 4G. The numbers include postpaid and prepaid users.
We conducted the 4G speed test at seven popular shopping centres: Clementi Mall, ION Orchard, nex, Paragon, Plaza Singapura, Raffles City and Westgate.
Our tests captured download and upload speeds over the three telcos' networks using the Ookla Speed-test app on the Samsung Note Edge, and standardised the speed tests on NewMedia servers. We also recorded the time taken to download a 150MB file from Dropbox and a 140MB app from Google Play store.
The tests were done during lunchtime, when crowds normally gather, mainly on the ground floor and basement one level of the malls.
We also checked at random for blind spots, where no data connection can be established at all.
Connections were spotty on the second floor of nex in Serangoon, outside the Watsons and Courts stores.
StarHub's and M1's networks had only intermittent access to WhatsApp, Facebook and Twitter.
Ms Christine Lai, 55, a sales and marketing executive who often visits nex, said there are connection problems on certain floors. "I still get distorted ringtones or no dial tone on my Singtel and StarHub lines," she said, adding that "nex is possibly the worst venue in Singapore to get mobile connections".
Generally, surfing speeds across the three mobile networks at the locations ranged from as low as 3Mbps to as high as 149.3Mbps.
The fastest and slowest download speeds were encountered at Raffles City. StarHub had readings of 3Mbps on the ground floor, while M1 clocked 3.6Mbps at the basement one level.
At such low speeds, we were unable to complete downloading the 150MB file from Dropbox over StarHub's network. It took about four minutes to download the same file over M1's network.
The 150MB file also could not be downloaded over StarHub's network at nex, Paragon and ION Orchard, although StarHub's network registered surfing speeds ranging from 15Mbps to 32Mbps.
Even more puzzling is that the 140MB app from Google Play store took under two minutes to download over StarHub at the same spots where we were unable to transfer the Dropbox file.
The highest speed of 149.3Mbps was registered by M1 on the ground floor of Raffles City.
Singtel outperformed its rivals at several locations and had the most consistent performance. It clocked a blazing 149Mbps at the basement one level of Plaza Singapura.
Even so, high download speeds do not necessarily translate into faster file downloads.
For instance, at basement one of Plaza Singapura, where Singtel registered 149Mbps, it took 53 seconds to download the Dropbox file. The file took just as long to download at Paragon's basement one, where Singtel registered only one-third of the surfing speed - 56Mbps.
Mr Mike Ang, president of the Association of Telecommunications Industry of Singapore, said actual user experience is affected by many factors. "The design of the mobile network, the type of Internet traffic carried and the speed of the backhaul link connecting mobile base stations to the Internet play a part," he said. A congested network could result in a long download time.
StarHub said its mobile equipment at the test locations offers peak 4G speeds of 75Mbps. It is still upgrading its network to the peak theoretical speed of 300Mbps.
Among the first buildings to get this boost are Marina Bay Sands and Suntec City Mall, where typical surfing speeds are 230Mbps, StarHub said. Some 40 high-traffic commercial buildings and malls, including VivoCity, nex, ION Orchard and Tampines 1, are being targeted for a 4G speed boost by the end of next year.
Of the poor Dropbox experience, StarHub's spokesman said: "We have since optimised the Internet routes to Dropbox servers... for our customers to enjoy a more consistent experience, just like we did for popular content sites Amazon, Apple, Facebook, Google, Microsoft, Twitter and YouTube."
Meanwhile, M1 said it had found a defective indoor antenna, which affected surfing speeds at the basement one level of Raffles City.
"Pending building owner permission, we expect to replace the defective equipment within a week," said an M1 spokesman.
He added that the telco will send another team to check for connection problems at nex.
Over the next two years, M1 will install new in-building technologies dubbed 4G small cells in busy buildings such as nex and Clementi Mall, as well as at MRT station platforms in Orchard Road, Raffles Place and Jurong East, to remedy the speed gaps. The telco has already installed 4G small cells at Paragon.
Singtel said the indoor mobile system at nex is shared with StarHub and M1. But it is in discussion with the mall's owner to complete network upgrade plans to improve mobile data connections there within the next two months.
Singtel added that services such as Dropbox connect to servers overseas, and "extend beyond the local mobile network". So, download speeds may not be consistent.
Last month, the Infocomm Development Authority (IDA) released findings showing 4G mobile users had been getting data download speeds of between 5.1 Mbps and 42.4 Mbps from all three telcos.
IDA, which collected data from 4,000 mobile users via a mobile app, said these speeds were "good enough" for social networking, video streaming and online gaming. Some blind spots - which IDA would not name - were also reported in Tampines.
Additional reporting by Sherwin Loh