Hong Kong’s CSL announced today it has upgraded parts of its 4G network to LTE-Advanced using carrier aggregation across two 20MHz bands to offer theoretical peak download speeds of 300Mb/s.

CSL has 20MHz of spectrum in each of the 1.8 and 2.6GHz bands and aggregates the two blocks to boost the speed of its 4G network from 150 to 300Mb/s in parts of Hong Kong. From 22 December coverage will include New Territories districts (from Shatin to Sheung Shui) as well as the MTR’s new West Island Line (three stations) beginning on 28 December.

Customers need compatible Cat 6 devices to benefit from the upgrade.

CSL, which was acquired from Telstra by Hong Kong Telecom (HKT) in May, first announced plans for dual-band LTE-A in Barcelona at the Mobile World Congress in February and claimed to be the first to offer the high-speed mobile service.

But in September SingTel launched what it said was the world’s first commercial LTE-A network supporting theoretical peak download speeds of up to 300Mb/s.

In June South Korea’s SK Telecom announced that its new LTE-A service supports speeds of up to 225Mb/s using carrier aggregation. SK’s rival LG Uplus has also trialled tri-band LTE carrier aggregration using kit from Huawei, which it claims can offer peak speeds of 300Mb/s. It planned to launch commercial services later this year.

In May Telstra demonstrated network speeds of 450Mb/s also using LTE-A carrier aggregation technology.

CSL is the territory’s largest mobile operator with 4.6 million connections and almost a 37 per cent market share after the merger (PCCW Mobile users have been migrated to the CSL brand). Almost a third of its subscribers are 4G.