CNA Explains: How radio frequency bands are regulated – and why it matters for telcos

“You can think of spectrum as a fixed-size waterpipe … The more people who demand water, the bigger the demand on the pipe, the less the allocation on the pipe per user,” she explained.

“Mobile network operators want as much spectrum as possible in order to cater to all these mobile users surfing the internet, accessing e-government services or making phone calls.”

While only four telco companies are licensed to use the spectrum for mobile services, people can still use other operators like Circles.Life and MyRepublic.

These operators lease network capacity from Singtel, StarHub and M1 or have been launched as sub-brands of these companies.

How might radio frequency bands be used outside authorised allocations? 

In some cases, the use of frequencies outside these allocations may occur due to technical issues such as equipment misconfiguration, Ms Hemrajani told CNA.

There may also be arrangements between operators to share spectrum, although such agreements typically require regulatory approval.

A more serious scenario would be when unassigned frequency bands are used by an “illegal spectrum squatter”.

This can happen when “one operator is desperate in need of spectrum to cater to its subscribers and hence temporarily ‘borrowed’ spectrum from another operator that it had noticed was not being used at that location or time”, Ms Hemrajani explained.

Unauthorised use of spectrum – whether intentional or inadvertent – can lead to interference between networks. This may affect service quality, including slower data speeds or reduced coverage.

Ms Hemrajani, who said she has investigated such cases, pointed to a case she worked on in Hong Kong, where a store’s shoplifting detection system illegally used a narrow part of the spectrum assigned to a mobile phone operator.

“(We) had to advise them to stop so that the mobile network operator’s network quality would not suffer,” she said.